Nonwovens produced from multicomponent fibers

ES 2 403 114 T3

DESCRIPTION

Nonwoven materials produced from multicomponent fibers.

Field of the invention

The invention pertains to microdenier fibers and nonwoven cloths prepared therefrom. Fibers and fibrous articles have applications in toilet flushable personal hygiene products and medical products.

Background of the invention

Melt fibers and webs and other melt-spun fibrous articles have been prepared from thermoplastic polymers, such as poly (propylene), polyamides, and polyesters. A common application of these fibers and fibrous articles is nonwoven cloths and, in particular, in personal hygiene products such as wipes, feminine hygiene products, baby diapers, adult incontinence pants, hospital / surgical supplies and others. disposable medical supplies, protective cloths and capes, geotextiles, industrial wipes and filter media. Unfortunately, personal hygiene products made from conventional thermoplastic polymers are difficult to dispose of and are often landfilled. A promising alternative method of disposal is to make these products or their components flushable, that is, compatible with public sanitation systems. The use of water-dispersible or water-soluble materials also improves the recyclability and recovery of personal hygiene products. The different thermoplastic polymers currently used in personal hygiene products are not inherently soluble or dispersible in water and, therefore, do not generate articles that disintegrate easily and can be disposed of through the sanitation system or recycled. In a simple way.

The desire for toilet flushable personal hygiene products has resulted in the need for fibers, nonwovens, and other fibrous articles with varying degrees of response. Various approaches to address these needs have been described, for example, in US Patent Nos. 6,548,592; 6,552,162; 5,281,306; 5,292,581; 5,935,880; and 5,509,913; United States Patent Application No. Serial 09 / 775,312; and 09 / 752,017; and PCT International Publication No. WO 01/66666 A2. However, these approaches have a number of disadvantages and do not provide a fibrous article, such as a fiber or nonwoven cloth, that possesses a satisfactory balance of performance properties, such as tensile strength, absorption, flexibility and cloth integrity. in both wet and dry conditions.

For example, typical nonwoven technology is based on the multidirectional deposition of fibers that are treated with a resin bonding adhesive to form a network that has strong integrity and other desirable properties. The resulting assemblies, however, generally have a poor response to water and are not suitable for flushable applications. The presence of a binder can also result in undesirable properties in the final product, such as lower sheet wettability, higher toughness, adhesion, and higher production costs. It is also difficult to generate a binder that exhibits proper wet strength during use and that disperses rapidly after removal. Thus, nonwoven assemblies using these binders can either slowly disintegrate under ambient conditions or have less than adequate wet strength properties in the presence of body fluids. To address this problem, ion- and pH-sensitive water-dispersible binders, such as lattice structures containing acrylic or methacrylic acid with or without added salts, are currently known and described, for example, in US Pat. 6,548,592 B1. However, ionic concentrations and pH levels of residential septic and public sanitation systems can vary widely with geographic location and may not be sufficient for the binder to become soluble and disperse. In this case, fibrous items do not disintegrate after disposal and can clog drains or sewer sides.

Multi-component fibers containing a water dispersible component and a non-water dispersible thermoplastic component have been described, for example, in US Patent Nos. 5,916,678; 5,405,698; 4,966,808; 5,525,282; 5,366,804; 5,486,418.

United States Patent No. 5,916,678 discloses multicomponent fibers that include bicomponent fibers that have at least one component that allows the fibers to bond to themselves and other types of fibers and wherein the same component is also biodegradable in an aqueous medium.

For example, these multicomponent fibers can be a bicomponent fiber having a conformed or screened reverse cross-section such as, for example, an island-in-the-sea, core and shell, side-by-side or segmented pie configuration. . The segmented fiber can be subjected to water or a dilute alkaline solution in which the non-water dispersible component is dissolved to leave behind the water dispersible component as separate and independent fibers of extremely small fineness. However, polymers that have good dispersibility in water often impart tackiness to the resulting multicomponent fibers, causing the fibers to stick, block, or melt during winding.

ES 2 403 114 T3 or storage after several days, especially in hot or humid conditions. To prevent melting, a fatty acid or oil-based finish is often applied to the surface of the fiber. In addition, large amounts of pigments or fillers are sometimes added to the water-dispersible polymers to prevent melting of the fibers as discussed above, for example, in US Pat. 6,171,685. Such oil finishes, pigments, and fillers require additional processing steps and can impart unwanted properties to the final fiber. Many water-dispersible polymers also require alkaline solutions for their removal, which causes degradation of other polymeric components of the fiber such as, for example, reduction in inherent viscosity, toughness, and melt strength. Furthermore, some water dispersible polymers cannot withstand exposure to water during hydroentangling and thus are not suitable for the manufacture of nonwoven nets and cloths.

Alternatively, the water dispersible component can serve as a bonding agent for thermoplastic fibers in nonwoven webs. Upon exposure to water, the fiber-to-fiber bonds fall apart so that the nonwoven web loses its integrity and breaks into individual fibers. The thermoplastic fiber components of these non-woven nets, however, are not dispersible in water and remain present in the aqueous medium and thus must be removed over time from municipal wastewater treatment plants. Hydroentangling can be used to produce disintegrable nonwovens with or without very low levels (<5% by weight) of binder added to hold the fibers together. Although these cloths can disintegrate upon disposal, they often use fibers that are not water soluble or water dispersible and can result in entanglement and clogging of sewer systems. It is necessary that any added water dispersible binders are minimally affected by hydroentangling and do not form gelatinous build-ups or cross-linking, and thus contribute to cloth handling or sewer-related problems.

A few water-dispersible or water-soluble polymers are available, but are not generally applicable to melt blown fiber forming or general melt spinning operations. Polymers, such as polyvinyl alcohol, polyvinyl pyrrolidone, and poly (acrylic acid) cannot be melt processed as a result of thermal decomposition that occurs at temperatures below the point where the proper mass viscosity is achieved. fused. The high molecular weight polyethylene oxide has appropriate thermal stability, but would provide a high viscosity solution at the polymer interface resulting in a slow disintegration rate. Water dispersible sulfopolyesters have been described, for example, in US Patent Nos. 6,171,685; 5,543,488; 5,853,701; 4,304,901; 6,211,309; 5,570,605; 6,428,900 and 3,779,993.

WO discloses a multicomponent fiber having a shaped cross section, said multicomponent fiber comprising at least one water dispersible sulfopolyester; and a plurality of domains comprising one or more non-water dispersible polymers immiscible with said sulfopolyester.

However, typical sulfonyl esters are low molecular weight thermoplastics that are brittle and lack the flexibility to withstand a winding operation to result in a roll of material that does not fracture or crumble. Sulfopolyesters can also exhibit blocking or melting during processing to form a film or fibers, which may require the use of oil finishes or avoiding large amounts of pigments or fillers. Low molecular weight polyethylene oxide (more commonly known as polyethylene glycol) is a weak / brittle polymer that also does not have the physical properties required for fiber applications. Forming fibers from known water soluble polymers by dissolution techniques is an alternative, but the added complexity of removing solvent, especially water, raises manufacturing costs.

Accordingly, there is a need for a water-dispersible fiber and fibrous articles prepared therefrom that exhibit appropriate tensile strength, absorption, flexibility, and cloth integrity in the presence of moisture, especially after exposure to human body fluids. . In addition, there is a need for a fibrous article that does not require a binder and that will disperse completely or dissolve in municipal or residential sanitation systems. Potential uses include, but are not limited to, melt webs, spunbonded cloths, hydroentangled cloths, dry-warped nonwovens, bicomponent fiber components, adhesive promotion layers, binders for cellulosic materials, materials odorless nonwovens and films, dissolvable binder fibers, protective layers and vehicles for releasing or dissolving active ingredients in water. It is also necessary that the multicomponent fiber having a water dispersible component does not exhibit excessive blockage or melting of filaments during spinning operations, is easily removed with hot water at a neutral or slightly acidic pH, and is suitable for hydroprocessing processes. -interlacing for the manufacture of non-woven cloths. These multicomponent fibers can be used to produce microfibers that can be used to produce various articles. Other melt-spun and extrudable fibrous materials are also possible.

Summary of the invention

The present invention provides a non-dispersible polymer microfiber, a non-woven article comprising the non-dispersible polymer microfiber, and a process for producing the non-woven article, as defined in the

ES 2 403 114 T3 claims. Flexible, water-dispersible fibers can be prepared from sulfopolyesters. Described herein is a water dispersible fiber comprising:

(A) a sulfopolyester having a glass transition temperature (Tg) of at least 25 ° C, the sulfopolyester comprising (i) residues of one or more dicarboxylic acids;

(ii) from about 4 to about 40 mole%, based on total repeat units, of residues of at least one sulfomonomer having 2 functional groups and one or more sulfonate groups attached to an aromatic or cycloaliphatic ring in which the functional groups are hydroxyl, carboxyl, or a combination thereof;

(iii) one or more diol residues in which at least 25% by mole, based on the total diol residues, is a poly (ethylene glycol) having the structure

H- (OCH2-CH2) n-OH where n is an integer within the range of 2 to about 500; and (iv) from 0 to about 25% by mole, based on total repeating units, of residues of a branching monomer having 3 or more functional groups in which the functional groups are hydroxyl, carboxyl, or a combination thereof. ;

(B) optionally, a water dispersible polymer mixed with the sulfopolyester; and (C) a non-dispersible polymer blended with the sulfopolyester wherein the blend is an immiscible blend;

wherein the fiber contains less than 10% by weight of a pigment or filler, based on the total weight of the fiber.

The fibers described herein can be one-component fibers that disperse rapidly or dissolve in water and can be produced by melt blowing or melt spinning. The fibers are prepared from the sulfopolyester with a non-water dispersible polymer. The fibers can include a water dispersible polymer mixed with the sulfopolyester. The fiber includes a non-water dispersible polymer blended with the sulfopolyester, where the blend is an immiscible blend. Fibrous articles comprising the water dispersible fibers are also described. Thus, the fibers can be used to prepare various fibrous articles, such as yarns, melt blown nets, spunbonded nets, and nonwoven cloths which are, in turn, water dispersible or flushable. Short fibers can also be mixed with natural or synthetic fibers in paper, non-woven webs and textile yarns.

Another aspect described herein is a water dispersible fiber comprising:

(A) a sulfopolyester having a glass transition temperature (Tg) of at least 25 ° C, the sulfopolyester comprising:

(i) from about 50 to about 96 mole% of one or more isophthalic acid or terephthalic acid residues, based on total acid residues;

(ii) from about 4 to about 30% by mole, based on total acid residues, of a residue of sodium sulfoisophthalic acid;

(iii) one or more diol residues in which at least 25% by mole, based on total diol residues, is a poly (ethylene glycol) having a structure

H- (OCH2-CH2) n-OH where n is an integer within the range of 2 to about 500; and (iv) from 0 to about 20% by mole, based on total repeating units, of residues of a branching monomer having 3 or more functional groups in which the functional groups are hydroxyl, carboxyl, or a combination thereof. ;

(B) optionally, a water dispersible polymer mixed with the sulfopolyester; and (C) a non-dispersible polymer mixed with the sulfopolyester to form a blend wherein the blend is an immiscible blend;

wherein the fiber contains less than 10% by weight of a pigment or filler, based on the total weight of the fiber.

ES 2 403 114 T3

Fibrous and water dispersible articles include personal hygiene items such as, for example, wipes, gauze, tissues, diapers, toilet training pants, sanitary napkins, bandages, surgical and wound healing dressings. In addition to being water dispersible, fibrous articles are flushable, that is, compatible with and suitable for disposal through municipal and residential sanitation systems.

Also described herein is a multicomponent fiber comprising a water dispersible sulfopolyester and one or more non-water dispersible polymers. The fiber has a geometry subjected to technical study such that the non-water dispersible polymers are present in the form of segments substantially isolated from each other by the intervening sulfopolyester, which acts as a binder or encapsulating matrix for the non-water dispersible segments. Thus, another aspect described herein is a multicomponent fiber having a shaped cross section, comprising:

(A) a water dispersible sulfopolyester having a glass transition temperature (Tg) of at least 57 ° C, the sulfopolyester comprising:

(i) residues of one or more dicarboxylic acids;

(ii) from about 4 to about 40 mole%, based on total repeat units, of residues of at least one sulfomonomer having 2 functional groups and one or more sulfonate groups attached to an aromatic or cycloaliphatic ring in which the functional groups are hydroxyl, carboxyl, or a combination thereof;

(iii) one or more diol residues in which at least 25% by mole, based on total diol residues, is a poly (ethylene glycol) having a structure

H- (OCH2-CH2) n-OH where n is an integer within the range of 2 to about 500; and (iv) from 0 to about 25% by mole, based on total repeating units, of residues of a branching monomer having 3 or more functional groups in which the functional groups are hydroxyl, carboxyl, or a combination thereof. ;

(B) a plurality of segments comprising one or more non-water dispersible polymers immiscible with the sulfopolyester, wherein the segments are substantially isolated from one another by the sulfopolyester intervening between the segments;

wherein the fiber contains less than 10% by weight of a pigment or filler, based on the total weight of the fiber.

Sulfopolyester has a glass transition temperature of at least 57 ° C which greatly reduces fiber blocking and melting during winding and long-term storage.

The sulfopolyester can be removed by contacting the multicomponent fiber with water to leave behind the non-water dispersible segments in the form of microdenier fibers. Described herein is a process for microdenier fibers comprising:

(A) spinning a water dispersible sulfopolyester having a glass transition temperature (Tg) of at least 57 ° C and one or more non-water dispersible polymers immiscible with the sulfopolyester to give multicomponent fibers, the sulfopolyester comprising:

(i) from about 50 to about 96 mole% of one or more isophthalic acid or terephthalic acid residues, based on total acid residues;

(ii) from about 4 to about 30%, based on total acid residues, of a sodium sulfoisophthalic acid residue;

(iii) one or more diol residues in which at least 25% by mole, based on the total diol residues, is a poly (ethylene glycol) having a structure

H- (OCH2-CH2) n-OH where n is an integer within the range of 2 to about 500; and (iv) from 0 to about 20% by mole, based on total repeat units, of residues of a branching monomer having 3 or more functional groups in which the functional groups are hydroxyl, carboxyl, or a combination thereof. ;

ES 2 403 114 T3 in which the fibers have a plurality of segments comprising the non-water dispersible polymers in which the segments are substantially isolated from each other by the sulfopolyester intervening between the segments and the fibers contain less than 10% by weight of a pigment or filler, based on the total weight of the fibers; and (B) contacting the multicomponent fibers with water to remove the sulfopolyester thereby forming microdenier fibers.

Non-water dispersible polymers can be susceptible to biodegradation as determined by DIN Standard 54900 and / or susceptible to biodegradation as determined by ASTM D6340-98 Standard Method. Multicomponent fibers can also be used to prepare a fibrous article such as a yarn, cloth, melt blown web, spunbonded web, or nonwoven cloth and which may comprise one or more layers of fibers. The fibrous article having multicomponent fibers, in turn, is contacted with water to produce fibrous articles containing microdenier fibers.

Another aspect described herein is a process for a microdenier fiber network, comprising:

(A) spinning a water dispersible sulfopolyester having a glass transition temperature (Tg) of at least 57 ° C and one or more non-water dispersible polymers immiscible with the sulfopolyester to give multicomponent fibers, the sulfopolyester comprising:

(i) from about 50 to about 96 mole% of one or more isophthalic acid or terephthalic acid residues, based on total acid residues;

(ii) from about 4 to about 30%, based on total acid residues, of a sodium sulfoisophthalic acid residue;

(iii) one or more diol residues in which at least 25% by mole, based on the total diol residues, is a poly (ethylene glycol) having a structure

H- (OCH2-CH2) n-OH where n is an integer within the range of 2 to about 500; and (iv) from 0 to about 20% by mole, based on total repeat units, of residues of a branching monomer having 3 or more functional groups in which the functional groups are hydroxyl, carboxyl, or a combination thereof. ;

wherein the fibers have a plurality of segments comprising the non-water dispersible polymers and the segments are substantially isolated from each other by the sulfopolyester intervening between the segments and the fibers contain less than 10% by weight of a pigment or substance filler, based on the total weight of said fibers; and (B) overlapping and collecting the multicomponent fibers from Step A to form a nonwoven web; and (C) contacting the nonwoven web with water to remove the sulfopolyester thereby forming a microdenier fiber web.

Also described herein is a process for preparing a water dispersible nonwoven cloth comprising:

(A) heating a water dispersible polymer composition to a temperature above its pour point, wherein the polymer composition comprises (i) a sulfopolyester having a glass transition temperature (Tg) of at least 25 ° C, comprising the sulfopolyester:

(a) residues of one or more dicarboxylic acids;

(b) from about 4 to about 40 mole%, based on total repeat units, of residues of at least one sulfomonomer having 2 functional groups and one or more metal sulfonate groups attached to an aromatic or cycloaliphatic ring in where the functional groups are hydroxyl, carboxyl, or a combination thereof;

(c) one or more diol residues in which at least 20% by mole, based on the total diol residues, is a poly (ethylene glycol) having the structure

H- (OCH2-CH2) n-OH where n is an integer within the range of 2 to about 500;

ES 2 403 114 T3 (d) from 0 to about 25% by mole, based on total repeat units, of residues of a branching monomer having 3 or more functional groups in which the functional groups are hydroxyl, carboxyl or one of its combinations;

(ii) optionally, a water dispersible polymer mixed with the sulfopolyester; and (iii) optionally, a non-water dispersible polymer mixed with the sulfopolyester to form a blend provided that the blend is an immiscible blend;

wherein the polymer composition contains less than 10% by weight of a pigment or filler, based on the total weight of the polymer composition;

(B) melt spinning filaments; and (C) overlapping and collecting the filaments from Step B to form a nonwoven web.

In another aspect of the present invention, there is provided a multicomponent fiber, having a shaped cross section, comprising:

(A) at least one water dispersible sulfopolyester; and (B) a plurality of microfiber domains comprising one or more non-water dispersible polymers immiscible with the sulfopolyester, wherein the domains are substantially isolated from each other by means of the sulfopolyester intervening between the domains;

wherein the fiber has a denier in spun form of less than about 6 denier per filament;

wherein the water dispersible sulfopolyesters exhibit a melt viscosity of less than about 12,000 poise measured at 240 ° C at a stress rate of 1 rad / s, and wherein the sulfopolyester comprises less than about 25 mole% of residues of at least one sulfomonomer, based on total moles of diacid or diol residues.

Another aspect described in the present invention is a multicomponent extruded fraction having a shaped cross section, comprising:

(A) at least one water dispersible sulfopolyester; and (B) a plurality of domains comprising one or more non-water dispersible polymers immiscible with the sulfopolyester, wherein the domains are substantially isolated from one another by the sulfopolyester intervening between the domains, wherein the fraction subjected to extrusion is capable of melt extraction at a speed of at least about 2000 m / min.

Another aspect described herein is a process for preparing a multicomponent fiber having a shaped cross section comprising spinning at least one water-dispersible sulfopolyester and one or more non-water-dispersible polymers immiscible with the sulfopolyester, wherein the multicomponent fiber has a plurality of domains comprising non-water dispersible polymers and the domains are substantially isolated from one another by the intervening sulfopolyester; wherein the multicomponent fiber has a denier in spun form of less than about 6 denier per filament; wherein the dispersible sulfopolyester exhibits a melt viscosity of less than about 12,000 poise measured at 240 ° C at a stress rate of 1 rad / s, and wherein the sulfopolyester comprises less than about 25 mole% residue of at least one sulfomonomer, based on total moles of diacid or diol residues.

Another aspect described herein is a process for preparing a multicomponent fiber having a shaped cross section which comprises extruding at least one water dispersible sulfopolyester and one or more non-water dispersible polymers immiscible with the sulfopolyester to produce a fraction subjected to multicomponent extrusion, wherein the multicomponent extruded fraction has a plurality of domains comprising said non-water dispersible polymers and said domains are substantially isolated from each other by said sulfopolyester intervening between said domains; and melt extracting the multicomponent extruded fraction at a speed of at least about 2000 m / min to produce the multicomponent fiber.

Another aspect described herein is a process for producing microdenier fibers comprising:

(A) spinning at least one water-dispersible sulfopolyester and one or more non-water-dispersible polymers immiscible with the water-dispersible sulfopolyester to give multicomponent fibers, wherein the multicomponent fibers have a plurality of domains comprising the non-water dispersible polymers in which the domains are substantially isolated from each other by the sulfopolyester intervening between said

ES 2 403 114 T3 domains; wherein the multicomponent fiber has a denier in spun form of less than about 6 denier per filament; wherein said water dispersible sulfopolyester exhibits a melt viscosity of less than about 12,000 poise measured at 240 ° C at a stress rate of 1 rad / s, and wherein the sulfopolyester comprises less than about 25 mole% of residues of at least one sulfomonomer, based on total moles of diacid or diol residues; and (B) contacting the multicomponent fibers with water to remove said water dispersible sulfopolyester thereby forming microdenier fibers of the non-water dispersible polymer (s).

Another aspect described herein is a process for producing microdenier fibers comprising:

(A) extruding at least one water-dispersible sulfopolyester and one or more non-water-dispersible polymers immiscible with the water-dispersible sulfopolyester to produce multicomponent extruded fractions, wherein the multicomponent extruded fractions have a plurality of domains comprising the non-water dispersible polymers wherein the domains are substantially isolated from one another by the intervening sulfopolyester;

(B) melt extracting the multicomponent extruded fractions at a speed of at least about 2000 m / min to form multicomponent fibers; and (C) contacting the multicomponent fibers with water to remove said water dispersible sulfopolyester thereby forming microdenier fibers of the non-water dispersible polymer (s).

Another aspect described herein is a process for preparing a network of microdenier fibers comprising:

(A) spinning at least one water-dispersible sulfopolyester and one or more non-water-dispersible polymers immiscible with the sulfopolyester to give multicomponent fibers, multicomponent fibers have a plurality of domains comprising non-water dispersible polymers in the that the domains are substantially isolated from one another by the water dispersible sulfopolyester intervening between the domains; wherein the multicomponent fiber has a denier in spun form of less than about 6 denier per filament; wherein the water dispersible sulfopolyester exhibits a melt viscosity of less than about 12,000 poise measured at 240 ° C at a stress rate of 1 rad / s, and wherein the sulfopolyester comprises less than about 25 mole% of residues of at least one sulfomonomer, based on total moles of diacid or diol residues;

(B) collecting the multicomponent fibers from Step (A) to form a nonwoven web; and (C) contacting the nonwoven web with water to remove the sulfopolyester thereby forming a network of microdenier fibers.

In another aspect, a process for preparing the microdenier fiber network is described herein, comprising:

(A) extruding at least one water-dispersible sulfopolyester and one or more non-water-dispersible polymers immiscible with the sulfopolyester to produce a multicomponent extruded fraction, the multicomponent extruded fraction having a plurality of domains comprising non-water dispersible polymers in which the domains are substantially isolated from each other by the sulfopolyester intervening between the domains;

(B) melt extracting the multicomponent extruded fractions at a speed of at least about 2000 m / min to form multicomponent fibers; and (C) collecting the multicomponent fibers from Step (B) to form a non-woven network; and (D) contacting the nonwoven web with water to remove said sulfopolyester thereby forming a microdenier fiber web.

In another embodiment, a process for producing a non-water dispersible polymer microfiber is described herein, the process comprising:

a) cutting a multicomponent fiber into chopped multicomponent fibers;

b) contacting the fiber-containing raw material with water to produce a fiber blend suspension; wherein the fiber-containing raw material comprises staple multicomponent fibers;

c) heating the fiber blend suspension to produce a hot fiber blend suspension;

d) optionally mixing the fiber blend suspension in a shear zone;

ES 2 403 114 T3

e) removing at least a portion of the sulfopolyester from the multicomponent fiber to produce a slurry mixture comprising a dispersion of the sulfopolyester and the non-water dispersible polymer microfibers; Y

f) separating the non-water dispersible polymer microfibers from the slurry mixture.

According to the invention, there is provided the non-water-dispersible polymer microfiber comprising at least one non-water-dispersible polymer in which the non-water-dispersible polymer has an equivalent diameter of less than 5 microns and a length of less than 3.5 millimeters.

In another embodiment of the present invention, a process for producing a nonwoven article from a non-water dispersible polymer is provided, the process comprising:

a) providing a non-water dispersible polymer microfiber produced from a multicomponent fiber; Y

b) producing a nonwoven article using a wet warp process or a dry warp process.

Detailed description

Water dispersible fibers and fibrous articles are described herein, which exhibit tensile strength, absorption, flexibility, and cloth integrity in the presence of moisture, especially upon exposure to human body fluids. Fibrous fibers and articles do not require the presence of oil, wax or fatty acid finishes or the use of large amounts (typically 10% by weight or more) of pigments or fillers to avoid blocking or melting of the fibers during processing. indicted. Furthermore, the fibrous articles prepared from the inventors' fibers do not require a binder and are easily dispersed or dissolved in domestic or public sanitation systems.

In a general embodiment, a water dispersible fiber is provided comprising a sulfopolyester having a glass transition temperature (Tg) of at least 25 ° C, wherein the sulfopolyester comprises:

(A) residues of one or more dicarboxylic acids;

(B) from about 4 to about 40 mole%, based on total repeat units, of residues of at least one sulfomonomer having 2 functional groups and one or more sulfonate groups attached to an aromatic or cycloaliphatic ring, wherein functional groups are hydroxyl, carboxyl, or a combination thereof;

(C) one or more diol residues in which at least 25% by mole, based on the total diol residues, is a poly (ethylene glycol) having a structure

H- (OCH2-CH2) n-OH where n is an integer within the range of 2 to about 500; and (iv) from 0 to 25% by mole, based on total repeat units, of residues of a branching monomer having 3 or more functional groups in which the functional groups are hydroxyl, carboxyl, or a combination thereof. Optionally, the fiber may include a water dispersible polymer mixed with the sulfopolyester and optionally a non-water dispersible polymer mixed with the sulfopolyester provided that the mixture is an immiscible blend. The fiber contains less than 10% by weight of a pigment or filler, based on the total weight of the fiber. Also described herein are fibrous articles comprising these fibers and may include personal hygiene products such as wipes, gauze, tissues, diapers, adult incontinence briefs, toilet training briefs, sanitary napkins, bandages, and dressings. surgical Fibrous articles can have one or more layers of absorbent fibers.

The fibers can be unicomponent, bicomponent or multicomponent fibers. For example, fibers can be prepared by melt spinning a single sulfopolyester or a blend of sulfopolyesters and include short, monofilament, and multifilament fibers with a shaped cross section. In addition, multicomponent fibers are provided, as described, for example, in US Pat. 5,916,678, which can be prepared by means of extrusion of the sulfopolyester and one or more non-water dispersible polymers, which are immiscible with the sulfopolyester, separately through a die having such a shaped or studied cross-sectional geometry such as an island-in-the-sea, core-deck, side-by-side, or segmented pie configuration. Subsequently, the sulfopolyester can be removed by dissolving the interfacial layers or pie segments and leaving the small filaments or microdenier fibers of the non-water dispersible polymer (s). These non-water dispersible polymer fibers have a much smaller fiber size than multi-component fiber prior to removal of the sulfopolyester. For example, the sulfopolyester and non-water dispersible polymers can be fed into a polymer delivery system in which the polymers are introduced into a segmented die plate. Polymers

ES 2 403 114 T3 follow separate paths to the fiber string and combine in the string hole comprising either two concentric circular holes thereby providing a core-sheath type fiber or a circular string hole divided along length of the diameter in multiple parts to provide a side-by-side type fiber. Alternatively, the water-dispersible and immiscible sulfopolyester and the non-water-dispersible polymers can be separately introduced into a spinneret having a plurality of radial passages to produce a multicomponent fiber having a segmented pie cross section. Typically, the sulfopolyester will form a shell component of a core and shell configuration. In fiber cross sections having a plurality of segments, the non-water dispersible segments are typically substantially isolated from one another by means of the sulfopolyester. Alternatively, the multicomponent fibers can be formed by melting the sulfopolyester and the non-water dispersible polymers in separate extrusion devices and directing the polymer flows into a spinneret with a plurality of distribution flow paths in shaped into small fine tubes or segments to provide a fiber having an islands-in-the-sea shaped cross-section. An example is described in US Patent No. 5,366,804. In the present invention, typically, the sulfopolyester will form the sea component and the non-water dispersible polymer will form the island component.

Unless otherwise indicated, it is to be understood that all numbers expressing amounts of ingredients, properties such as molecular weight, reaction conditions and the like, used in the specification and in the claims are in all cases modified by the term about. Accordingly, unless otherwise indicated, the numerical parameters explained in the following specification and in the appended claims are approximations that may vary depending on the desired properties that are intended to be obtained by means of the present invention. At the very end, each numerical parameter should be interpreted in light of the number of significant digits presented and applying ordinary rounding techniques. Furthermore, the ranges presented in the present disclosure and claims are intended to specifically include the entire range and not just the extreme (s). For example, a displayed range from 0 to 10 is intended to report all numbers between 0 and 10 such as, for example 1, 2, 3, 4, etc., all fractional numbers between 0 and 10, for example 1 , 5, 2,3, 4,57, 6,1113, etc, and the extremes 0 and

10. Also, a range associated with chemical substituent groups such as, for example, C1 to C5 hydrocarbons is intended to specifically include and disclose C1 and C5 hydrocarbons as well as C2, C3 and C4 hydrocarbons.

Although the numerical ranges and parameters that explain the broad scope of the invention are approximations, the numerical values ​​explained in the specific examples are presented as precisely as possible. However, any numerical value inherently contains errors that necessarily come from the standard deviation found in their respective test measurements.

The unicomponent fibers and the fibrous articles of the unicomponent fibers are water dispersible and typically disperse to complete form at room temperature. Elevated water temperatures can be used to accelerate its dispersibility or the removal rate of the multi-component or nonwoven fiber. The term "water dispersible," as used herein with respect to unicomponent fibers and fibrous articles made from unicomponent fibers, is intended to be synonymous with the terms "water-dissipable, capable of disintegration in water, capable of water soluble, water soluble, water removable, water soluble and water dispersible and the meaning in which the fiber or fibrous article is dispersed or dissolved is intended, in it or through it, by the action of water. The terms dispersed, dispersible, dissipated, or dissipable mean that, using a sufficient amount of deionized water (for example 100: 1 water: fiber by weight) to form a loose suspension or suspension of fibers or fibrous article, at a temperature of about 60 ° C, and within a period of up to 5 days, the fiber or fibrous article dissolves, disintegrates or separates into a plurality of non-uniform pieces or particles distributed more or less throughout the entire medium, such that no recognizable filaments are recovered from the medium after removal of the water, for example, by means of filtration or evaporation. Thus, water dispersible, as used herein, is not intended to include the simple disintegration of an interlaced or bonded, but otherwise water-insoluble or non-dispersible fiber assembly, wherein the assembly of Fibers are simply separated in water to produce a suspension of fibers in water that can be recovered by removal of the water. In the context of the present invention, all of these terms refer to the activity of water or the mixture of water and water-miscible co-solvent on the sulfopolyesters described herein. Examples of such water-miscible co-solvents include alcohols, ketones, glycol ethers, esters, and the like. This terminology is intended to include conditions under which the sulfopolyester dissolves to form a true solution as well as under which the sulfopolyester is dispersed in the aqueous medium. Often times, due to the statistical nature of sulfopolyester compositions, it is possible to have a soluble fraction and a dispersed fraction when placing a single sulfopolyester sample in an aqueous medium.

Similarly, the term "water dispersible," as used herein in reference to the sulfopolyester as a component of the multicomponent fiber or fibrous article, is also intended to be synonymous with the terms "water dissipable, capable of disintegration in water." , capable of dissolving in water, soluble in water, capable of being removed with water, water-soluble and water-dispersible and is intended to mean that the sulfopolyester component is sufficiently removed from the multicomponent fiber

ES 2 403 114 T3 and is dispersed or dissolved by the action of water to allow the release and separation of the non-water dispersible fibers present therein. The terms dispersed, dispersible, dissipated or dissipable mean that, using a sufficient amount of deionized water (for example 100: 1 water: fiber by weight) to form a loose suspension or suspension of fibers or fibrous article, at a temperature of about 60 ° C, and in a period of time of up to 5 days, the sulfopolyester dissolves, disintegrates or separates from the multicomponent fiber, leaving behind a plurality of microdenier fibers from the non-water dispersible segments.

The term "segment or domain or zone" when used to describe the conformed cross section of the multicomponent fiber refers to the area within the cross section comprising the non-water dispersible polymers in which these domains or segments are substantially isolated from one another. by means of the water dispersible sulfopolyester intervening between the segments or domains. The term "substantially isolated", as used herein, is intended to mean that the segments or domains are separated from each other to allow the segment domains to form individual fibers upon removal of the sulfopolyester. The segments or domains or areas may be of a similar size and shape or different size and shape. Again, the segments or domains or zones can take any configuration. These segments or domains or zones are substantially continuous along the length of the multicomponent extruded fiber or fraction. The term "substantially continuous" means continuous along at least 10 cm in length of the multicomponent fiber. These segments, domains or zones of the multicomponent fiber produce non-water dispersible polymer microfibers when the water dispersible sulfopolyester is removed.

As stated in the present disclosure, the shaped cross section of the multicomponent fiber can be, for example, core and shell shape, islands in the sea, segmented pie, hollow segmented pie, off-center segmented pie, etc.

The water dispersible fiber is prepared from polyesters, or more specifically sulfopolyesters, comprising dicarboxyic acid monomer residues, sulfomonomer residues, diol monomer residues and repeating units. The sulfomonomer can be a dicarboxylic acid, a diol, or a hydroxycarboxylic acid. Thus, the term "monomer residue", as used herein, means a residue of a dicarboxylic acid, a diol, or a hydroxycarboxylic acid. A repeating unit, as used herein, means an organic structure having 2 monomer residues linked through a carbonyloxy group. The sulfopolyesters described herein contain substantially equal molar ratios of acid residues (100 mol%) and diol residues (100 mol%), which react in substantially equal proportions such that the total moles of the repeating units are equal to 100% by mole. Thus, the mole percentages provided in the present disclosure may be based on the total moles of acid residues, the total moles of diol residues, or the total moles of repeating units. For example, a sulfopolyester containing 30% by mole of a sulfomonomer, which can be a dicarboxylic acid, a diol, or a hydroxycarboxylic acid, based on total repeating units, means that the sulfopolyester contains 30% by mole of sulfomonomer in a 100% total by mole of repeating units. Thus, there are 30 moles of sulfomonomer residues between every 100 moles of repeating units. Similarly, a sulfopolyester containing 30 mol% of a dicarboxylic acid sulfomonomer, based on total acid residues, means that the sulfopolyester contains 30 mol% sulfomonomer in a total of 100 mol% acid residues. . Thus, in the latter case, there are 30 moles of sulfomonomer residues between every 100 moles of acid residues.

The sulfopolyesters described herein have an inherent viscosity, hereinafter abbreviated Ih. V, of at least 0.1 dL / g, preferably about 0.2 to 0.3 dL / g, and most preferably greater than about 0.3 dL / g, measured at 60/40 parts by weight of phenol / tetrachloroethane solvent solution at 25 ° C and at a concentration of about 0.5 g of sulfopolyester in 100 ml of solvent. The term polyester, as used herein, encompasses both homopolyesters and copolyesters and means a synthetic polymer prepared by polycondensing difunctional carboxylic acids with a difunctional hydroxyl compound. As used herein, the term "sulfopolyester" means a polyester comprising a sulfomonomer. Typically, the difunctional carboxylic acid is a dicarboxylic acid and the difunctional hydroxyl compound is a dihydric alcohol such as, for example, glycols and diols. Alternatively, the difunctional carboxylic acid can be a hydroxy carboxylic acid such as, for example, p-hydroxybenzoic acid and the difunctional hydroxyl compound can be an aromatic nucleus bearing 2 hydroxy substituents such as, for example, hydroquinone. The term "residue", as used herein, means any organic structure incorporated into the polymer through a polycondensation reaction involving the corresponding monomer. Thus, the dicarboxylic acid residue can be derived from a dicarboxylic acid monomer or its associated acid halides, esters, salts, anhydrides, or mixtures thereof. As used herein, therefore, the term "dicarboxylic acid" is intended to include dicarboxylic acids and any derivatives of dicarboxylic acid, including their associated acid halides, esters, half-esters, salts, half-salts, anhydrides, anhydrides. mixtures or mixtures thereof, useful in the polycondensation process with a diol to prepare a high molecular weight polyester.

The sulfopolyester described herein includes one or more dicarboxylic acid residues. Depending on the type and concentration of the sulfomonomer, the dicarboxylic acid residue may comprise of

ES 2 403 114 T3 about 60 to about 100 mole% of the acid residues. Other examples of dicarboxylic acid residue concentration ranges are from about 60 mole% to about 95 mole% and from about 70 mole% to about 95 mole%. Examples of dicarboxylic acids that can be used include aliphatic dicarboxylic acids, alicylic dicarboxylic acids, aromatic dicarboxylic acids, or mixtures of two or more of these acids. Thus, suitable dicarboxylic acids include, but are not limited to, succinic; glutaric, adipic; azelaic; sebaceous; fumaric; maleic; itaconic; 1,3-cyclohexanedicarboxylic;

1,4-cyclohexanedicarboxylic; diglycolic; 2,5-norbornanedicarboxylic; phthalic; terephthalic; 1,4-naphthalene dicarboxylic; 2,5naphthalenedicarboxylic; diphenic; 4,4'-oxydibenzoic; 4,4'-sulfonyldibenzoic; and isophthalic. Preferred dicarboxylic acid residues are isophthalic, terephthalic and 1,4-cyclohexanedicarboxylic acids, or diesters, dimethyl terephthalate, dimethyl isophthalate and dimethyl 1,4-cyclohexanedicarboxylate are used, with isophthalic and terephthalic acid residues being especially preferred. Although the dicarboxylic acid methyl ester is the most preferred embodiment, the inclusion of higher order alkyl esters, such as ethyl, propyl, isopropyl, butyl, and the like, is also accepted. Furthermore, aromatic esters, in particular phenyl, can also be used.

The sulfopolyester includes about 4 to about 40% by mole, based on total repeating units, of residues of at least one sulfomonomer having 2 functional groups and one or more sulfonate groups attached to the aromatic or cycloaliphatic ring in which the groups functional are hydroxyl, carboxyl, or a combination thereof. Additional examples of concentration ranges for sulfomonomer residues are from about 4 to about 35% by mole, from about 8 to about 30% by mole, and from about 8 to about 25% by mole, based on total repeat units. . The sulfomonomer can be a dicarboxylic acid or one of its esters that contains a sulfonate group, a diol that contains a sulfonate group, or a hydroxy acid that contains a sulfonate group. The term "sulfonate" refers to a salt of a sulfonic acid having the structure -SO3M, where M is the cation of the sulfonate salt. The cation of the sulfonate salt can be a metal ion such as Li⁺, Na⁺, K⁺, Mg⁺⁺, Ca⁺⁺, Neither⁺⁺, Faith⁺⁺ and the like. Alternatively, the cation of the sulfonate salt can be non-metallic such as a nitrogenous base as described, for example, in US Patent No. 4,304,901. Nitrogen base cations are derived from nitrogen-containing bases, which can be aliphatic, cycloaliphatic, or aromatic compounds. Examples of such nitrogen-containing bases include ammonia, dimethylethanolamine, diethanolamine, triethanolamine, pyridine, morpholine, and piperidine. Typically, because monomers containing nitrogen-based sulfonate salts are not stable under the conditions required to prepare melt polymers, the method of preparing sulfopolyesters containing nitrogen-based sulfonate salt groups is to disperse , dissipate or dissolve the polymer containing the required amount of sulfonate group in the form of its alkali metal in water, and subsequently exchanging the alkali metal cation for a nitrogen-based cation.

When a monovalent alkali metal ion is used as the cation of the sulfonate salt, the resulting sulfopolyester is fully dispersible in water, the dispersion rate depending on the content of sulfomonomer in the polymer, the temperature of the water, the surface area / thickness of the sulfopolyester and the like. When a divalent metal ion is used, the resulting sulfopolyesters do not disperse easily in cold water but are more easily dispersed in hot water. The use of more than one counter ion in the individual polymer composition is possible and may provide a means to tailor or fine tune the water response of the resulting article of manufacture. Examples of sulfomonomer residues include monomer residues in which the sulfonate salt group is attached to an aromatic acid nucleus, such as, for example, benzene; naphthalene; diphenyl; oxydiphenyl; sulfonyldiphenyl; and methylenediphenyl or cycloaliphatic rings, such as, for example, cyclohexyl, cyclopentyl; cyclobutyl; cycloheptyl and cyclooctyl. Other examples of sulfomonomer residues that can be used in the present invention are the metal sulfonate salts of sulfphthalic acid, sulfoterephthalic acid, sulfoisophthalic acid, or combinations thereof. Other examples of sulfomonomers that can be used are 5-sodium sulfoisophthalic acid and its esters. If the sulfomonomer residue is 5-sodium sulfoisophthalic acid, typical sulfomonomer concentration ranges are from about 4 to about 35% by mole, from about 8 to about 30% by mole, and from about 8 to about 25% by mole, based on total moles of acid residues.

The sulfomonomers used in the preparation of the sulfopolyesters are known compounds and can be prepared using methods well known in the art. For example, sulfomonomers in which the sulfonate group is attached to an aromatic ring can be prepared by sulfonation of the aromatic compound with fuming sulfuric acid to obtain the corresponding sulfonic acid and followed by reaction with a metal or base oxide, for example, sodium acetate, to prepare the sulfonate salt. Procedures for the preparation of various sulfomonomers are described, for example, in US Patent Nos. 3,779,993, 3,018,272 and 3,528,947.

It is also possible to prepare the polyester using, for example, a sulfonate salt, and ion exchange methods to replace sodium with a different ion, such as zinc, when the polymer is in dispersed form. Generally, this type of ion exchange process is superior for preparing the polymer with divalent salts as the sodium salts are usually more soluble in the polymeric reactant melt phase.

The sulfopolyester includes one or more diol residues which can include aliphatic, cycloaliphatic, and aralkyl glycols. Cycloaliphatic diols, for example 1,3- and 1,4-cyclohexanedimethanol, may be present as their

ES 2 403 114 T3 pure cis and trans isomers or in the form of a mixture of cis and trans isomers. As used herein, the term "diol" is synonymous with the term "glycol" and means any dihydric alcohol. Examples of diols include, but are not limited to, ethylene glycol; diethylene glycol; triethylene glycol; polyethylene glycols; 1,3-propanediol; 2,4-dimethyl-2-ethylhexan-1,3diol; 2,2-dimethyl-1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol; 2-ethyl-2-isobutyl-1,3-propanediol; 1-3-butanediol; 1,4-butanediol; 1,5-pentanediol; 1,6-hexanediol; 2,2,4-trimethyl-1,6-hexanediol; thiodiethanol; 1,2-cyclohexanedimethanol; 1,3-cyclohexanedimethanol; 1,4-cyclohexanedimethanol; 2,2,4,4-tetramethyl-1,3-cyclobutanediol; p-xylylene diol or combinations of one or more of these glycols.

The diol residues can include from about 25% to about 100% by mole based on the total diol residues, of a poly (ethylene glycol) residue having the structure

H- (OCH2-CH2) n-OH where n is an integer within the range of 2 to 500. Non-limiting examples of low molecular weight polyethylene glycols, for example where n is 2 to 6, are diethylene glycol, triethylene glycol and tetraethylene glycol. Of these low molecular weight glycols, diethylene and triethylene glycol are the most preferred. High molecular weight polyethylene glycols (abbreviated herein as PEG), in which n is from 7 to about 500, include the commercially available products known under the designation CARBOWAX®, a product of the Dow Chemical Company (formerly Union Carbide) . Typically, PEGs are used in combination with other diols such as, for example, diethylene glycol or ethylene glycol. Based on the values ​​of n, which range from greater than 6 to 500, the molecular weight can range from greater than 300 to about 22,000 g / mol. Molecular weight and mole% are inversely proportional to each other; specifically, as the molecular weight increases, the mole% decreases in order to achieve the desired degree of hydrophilic nature. For example, it is illustrative of this concept to consider that PEGs having a molecular weight of 1000 may constitute up to 10 mole% of the total diol, while PEGs having a molecular weight of 10,000 will typically be incorporated at a level of less than 1% in moles of the total diol.

Certain dimer, trimer, and tetramer diols can be formed due to side reactions that can be controlled by varying process conditions. For example, varying amounts of diethylene glycols, triethylene glycols, and tetraethylene glycols can be formed from ethylene glycol from an acid-catalyzed dehydration reaction that occurs simply when the polycondensation reaction is carried out under acidic conditions. Buffers, as is well known to those skilled in the art, can be added to the reaction mixture to retard these side reactions. However, additional breadth of composition is possible, if the buffer is omitted and the dimerization, trimerization, and tetramerization reactions are allowed to proceed.

The sulfopolyester described herein can include from 0 to about 25% by mole, based on total repeat units, of residues of a branching monomer having 3 or more functional groups in which the functional groups are hydroxyl, carboxyl or one of its combinations. Non-limiting examples of branching monomers are 1,1,1-trimethylolpropane, 1,1,1-trimethylolethane, glycerin, pentaerythritol, erythritol, threitol, dipentaerythritol, sorbitol, trimellitic anhydride, pyromellitic dianhydride, dimethylolpropionic acid, or combinations thereof. Additional examples of branching monomer concentration ranges are 0 to about 20 mole% and 0 to about 10 mole%. The presence of a branching monomer can result in a number of possible advantages for the sulfopolyester including, but not limited to, the ability to tailor rheological, solubility, and tensile properties. For example, at a constant molecular weight, a branched sulfopolyester, compared to a linear analog, will also have a higher concentration of end groups which can facilitate post-polymerization crosslinking reactions. At high concentrations of branching agent, however, the sulfopolyester is likely to undergo gel formation.

The sulfopolyester used for the fiber described herein has a glass transition temperature, abbreviated herein as Tg, of at least 25 ° C, measured on the dry polymer using standard techniques, such as Differential Scanning Calorimetry (DSC ), well known to those of skill in the art. The Tg measurements of the sulfopolyesters are carried out using a dry polymer, that is, a polymer sample in which water is absorbed or adventitious is removed by heating the polymer to a temperature of about 200 ° C and allowing it to return the sample to room temperature. Typically, the sulfopolyester is dried in the DSC apparatus by carrying out a first thermal sweep in which the sample is heated to a temperature above the vaporization temperature of water, the sample is kept at this temperature until the completion of the test. vaporization of the water absorbed into the polymer (as indicated by a large and broad endotherm), cool the sample to room temperature and then carry out a second thermal scan to obtain the Tg measurement. Additional examples of glass transition temperatures exhibited by the sulfopolyester are at least 30 ° C, at least 35 ° C, at least 40 ° C, at least 50 ° C, at least 60 ° C, at least 80 ° C and at least minus 90 ° C. Although other Tg values ​​are possible, typical glass transition temperatures for dry sulfopolyesters are about 30 ° C, about 48 ° C, about 55 ° C, about 65 ° C, about 70 ° C, about 75 ° C, about 85 ° C and about 90 ° C.

ES 2 403 114 T3

Our novel fibers may consist essentially of, or consist of, the sulfopolyesters described above. In another embodiment, however, the sulfopolyesters can be a single polyester or they can be blended with one or more complementary polymers to modify the properties of the resulting fiber. The complementary polymer may or may not be water dispersible, depending on the application and may be miscible or immiscible with the sulfopolyester. If the complementary polymer is non-dispersible in water, it is preferable that the mixture with the sulfopolyester is immiscible. The term "immiscible", as used herein, is intended to mean that the mixture has a single, heterogeneous amorphous phase as indicated by an individual Tg value and depending on the composition. For example, a first polymer that is miscible with the second polymer can be used to plasticize the second polymer as illustrated, for example, in US Pat. 6,211,309. In contrast, the term "immiscible", as used herein, indicates a mixture that shows at least 2 phases, randomly mixed, and exhibits more than one Tg. Some polymers can be immiscible and still compatible with the sulfopolyester. A further overview of miscible and immiscible polymer blends and the different analytical techniques for their characterization can be found in Polymer Blends Volumes 1 and 2, Edited by DR Paul. and CB Bucknall, 2000, John Wiley & Sons, Inc.

Non-limiting examples of water dispersible polymers that can be blended with the sulfopolyester are poly (methacrylic acid), polyvinylpyrrolidone, copolymers of poly (ethylene acrylic acid), poly (vinyl methyl ether), poly (vinyl alcohol), poly (oxide ethylene), hydroxypropyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, ethyl hydroxyethyl cellulose, isopropyl cellulose, methyl ester starch, polyacrylamides, poly (N-vinyl caprolactam), polyethyl oxazoline, poly (2-isopropyl-2-oxazoline), poly (vinyl methyl oxazoline), water dispersible sulfopolyesters, poly (methyl vinyl oxazolidinone), poly (2,4-dimethyl-6-triazinylethylene) and oxide copolymers ethylene-propylene oxide. Examples of non-water dispersible polymers that can be blended with the sulfopolyester include, but are not limited to, polyolefins, such as homo- and copolymers of polyethylene and polypropylene; poly (ethylene terephthalate); poly (butylene terephthalate); and polyamides, such as nylon-6; polylactides; caprolactone, Eastar Bio® (poly (tetramethylene coterephthalate adipate), a product of Eastman Chemical Company); polycarbonate; polyurethane and poly (vinyl chloride).

Mixtures of more than one sulfopolyester can be used to tailor the end-use properties of the resulting fiber or fibrous article, eg, a cloth or net. Blends of one or more sulfopolyesters will have Tg values ​​of at least 25 ° C for water dispersible unicomponent fibers and at least 57 ° C for multicomponent fibers. In this way, the mixture can also be used to modify the processing characteristics of a sulfopolyester in order to facilitate the manufacture of a nonwoven material.

The sulfopolyester and complementary polymer can be mixed in continuous, semi-continuous or batch processes. Small-scale batches can be readily prepared in high intensity mixing devices well known to those skilled in the art, such as a Banbury mixing device, prior to melt spinning of the fibers. The components can also be mixed in solution in an appropriate solvent. The melt mixing method includes mixing the sulfopolyester and a complementary polymer at a temperature sufficient to melt the polymers. The mixture may be cooled and pelleted for later use or the melt may be melt spun directly from this melt mixture to form the fiber shape. The term "melt" as used herein includes, but is not limited to, simply softening the polyester. Generally, for melt mixing methods known in the polymer art see Mixing and Compounding of Polymers (I. Manas Zloczower & Z. Tadmor editors, Carl Hanser Verlag Publisher, 1994, New York, NY).

The inventors' disclosure also provides a water dispersible fiber comprising a sulfopolyester having a glass transition temperature (Tg) of at least 25 ° C, wherein the sulfopolyester comprises:

(A) from about 50 to about 96% by mole of one or more isophthalic acid or terephthalic acid residues, based on the total acid residues;

(B) from about 4 to about 30% by mole, based on total acid residues, of a sodium isophthalic acid residue;

(C) one or more diol residues in which at least 25% by mole, based on the total diol residues, is poly (ethylene glycol) having a structure

H- (OCH2-CH2) n-OH where n is an integer within the range of 2 to 500; (iv) 0 to about 20 mole%, based on total repeat units, of branching monomer residues having 3 or more functional groups in which the functional groups are hydroxyl, carboxyl, or a combination thereof. As described above, optionally, the fiber may include a first water-dispersible polymer in admixture with the sulfopolyester; and optionally a non-water dispersible polymer blended with the sulfopolyester so that the blend is an immiscible blend. Our fiber contains less than 10% by weight of a

ES 2 403 114 T3 pigment or filler, based on total fiber weight. The first water dispersible polymer is as described above. The sulfopolyester should have a glass transition temperature (Tg) of at least 25 ° C, but may have, for example, a Tg of about 35 ° C, about 48 ° C, about 55 ° C, about 65 ° C, about 70 ° C, about 75 ° C, about 85 ° C, and about 90 ° C. The sulfopolyester may contain other concentrations of isophthalic acid residues, for example, from about 60 to about 95% by mole, and from about 75 to about 95% by mole. Additional examples of concentration ranges for isophthalic acid residues are from 70 to about 85% by mole, from about 85 to about 95% by mole, and from about 90 to about 95% by mole. The sulfopolyester can also comprise from about 25 to about 95 mole% of the diethylene glycol residues. Additional examples of diethylene glycol residue concentration ranges include from about 50 to about 95% by mole, from about 70 to about 95% by mole, and from about 75 to about 95% by mole. The sulfopolyester can also include ethylene glycol and / or 1,4-cyclohexanedimethanol residues, abbreviated herein as CHDM. Typical concentration ranges for CHDM residues are from about 10 to about 75% by mole, from about 25 to about 65% by mole, and from about 40 to about 60% by mole. Typical concentration ranges for ethylene glycol residues are from about 10 to about 75% by mole, from about 25 to about 65% by mole, and from about 40 to about 60% by mole. In another embodiment, the sulfopolyester comprises from about 75 to about 96 mole% of the isophthalic acid residues and from about 25 to about 95 mole% of the diethylene glycol residues.

The sulfopolyesters described herein are readily prepared from the appropriate dicarboxylic acids, esters, anhydrides, or salts, sulfomonomer, and the appropriate diol or diol mixtures using typical polycondensation reaction conditions. They can be prepared by means of continuous, semi-continuous or batch modes of operation and can use a variety of types of reactors. Examples of suitable reactor types include, but are not limited to, stirred tank, continuous stirred tank, slurry, tubular, liquid film, drop film, or extrusion reactors. The term "continuous" as used herein means a process in which reactants are introduced and products are withdrawn simultaneously in an uninterrupted manner. By continuous it is meant that the process is of substantially or completely continuous operation and is in contrast to the batch process. Continuous does not in any way mean that it prohibits normal interruptions in process continuity due to, for example, start-up, reactor maintenance, or scheduled shutdown periods. The term "batch process" as used herein means a process in which all reactants are added to the reactor and subsequently processed according to the predetermined course of the reaction during which no material is fed to or removed from the reactor. . The term "semi-continuous" means a process in which some of the reactants are introduced at the beginning of the process and the remaining reactants are fed continuously as the reaction proceeds. Alternatively, the semi-batch process may also include a process similar to the batch process in which all reactants are added at the beginning of the process except that one or more products are removed continuously as the reaction proceeds. Advantageously, the process is operated as a continuous process for economic reasons and to produce superior coloration of the polymer as the appearance of the sulfopolyester deteriorates if it is allowed to reside in a reactor at elevated temperature for a long time.

The sulfopolyesters described herein are prepared by procedures known to those of skill in the art. Most often, the sulfomonomer is added directly to the reaction mixture from which the polymer is prepared, although other processes are known and may also be employed, for example, as described in US Pat. Nos. 3,018,272, 3,075,952 and 3,033,822. The reaction of the sulfomonomer, diol component, and dicarboxylic acid component can be carried out using conventional polyester polymerization conditions. For example, when sulfopolyesters are prepared by means of an ester exchange reaction, that is, from the ester form of the dicarboxylic acid components, the reaction process may comprise two stages. In the first stage, the diol component and the dicarboxylic acid component, such as, for example, dimethyl isophthalate, are reacted at elevated temperatures, typically, from about 150 ° C to about 250 ° C for about 0.5 at about 8 hours at pressures ranging from about 0.0 kPa gage pressure to about 414 kPa gage pressure (60 psig). Preferably, the temperature for the ester exchange reaction ranges from about 180 ° C to about 230 ° C for about 1 to about 4 hours, while the preferred pressure ranges from about 103 kPa gage pressure (15 psig) to about 276 kPa gage pressure (40 psig). Subsequently, the reaction product is heated to elevated temperatures and reduced pressure to form the sulfopolyester with the removal of the diol, which is easily volatilized under these conditions and is removed from the system. This second stage, or polycondensation stage, is continued under high vacuum conditions and at a temperature generally ranging from about 230 ° C to about 350 ° C, preferably from about 250 ° C to about 310 ° C and most preferably from about 260 ° C to about 290 ° C for about 0.1 to about 6 hours, or preferably, for about 0.2 to about 2 hours, until a polymer is obtained that

ES 2 403 114 T3 has the desired degree of polymerization, determined by inherent viscosity. The polycondensation step can be carried out under reduced pressure ranging from about 53 kPa (400 torr) to about 0.013 kPa (0.1 torr). Agitation or appropriate conditions are used in both stages to ensure proper heat transfer and surface renewal of the reaction mixture. The reactions of both stages are facilitated by means of appropriate catalysts such as, for example, titanium compounds, alkali metal hydroxides and alcoholates, organic carboxylic acid salts, alkyl titanium compounds, metal oxides and the like. A three-step manufacturing process, similar to that described in US Patent No. 5,290,631, in particular when a mixed monomer feed of acids and esters is used.

To ensure that the reaction of the diol component and the dicarboxylic acid component by means of an ester exchange reaction mechanism is carried out completely, it is preferable to employ from about 1.05 to about 2.5 moles of the component. diol relative to one mole of dicarboxylic acid component. However, those skilled in the art will understand that the ratio of the diol component to the dicarboxylic acid component is generally determined by the design of the reactor in which the reaction process takes place.

In the preparation of the sulfopolyester by means of direct esterification, that is, from the acid form of the dicarboxylic acid component, sulfopolyesters are produced by reacting the dicarboxylic acid or the mixture of dicarboxylic acids with the diol component or the mixture of diol components. The reaction is carried out at a pressure of from about 7 kPa gage pressure (1 psig) to about 1379 kPa gage pressure (200 psig), preferably less than 689 kPa (100 psig) to generate a linear or branched sulfopolyester product. low molecular weight having an average degree of polymerization of from about 1.4 to about 10. Typically, the temperatures employed during the direct esterification reaction range from about 180 ° C to about 280 ° C, more preferably they range from about 220 ° C to about 270 ° C. Subsequently, this low molecular weight polymer can be polymerized by means of a polycondensation reaction.

The multicomponent and water dispersible fibers and fibrous articles of the present disclosure may also contain other conventional additives and ingredients that do not adversely affect their end use. For example, additives such as fillers, surface friction modifiers, light and heat stabilizers, extrusion aids, antistatic agents, colorants, dyes, pigments, fluorescent brighteners, antimicrobials, anti-counterfeiting markers, hydrophobic improvers and hydrophiles, viscosity modifiers, slip agents, reinforcing agents, adhesion promoters, and the like.

The fibers and fibrous articles of the invention do not require the presence of additives such as, for example, pigments, fillers, oils, waxes or fatty acid finishes, to avoid blocking or melting of the fibers during processing. The terms "blocking" or "melting", as used herein, are understood to mean that the fibers or fibrous articles adhere together or melt to form a dough so that the fiber cannot or cannot be processed. use for your intended purpose. Blocking or melting can occur during processing of the fiber or fibrous article or during storage for a period of days or weeks and is exaggerated in hot and humid conditions.

In one embodiment of the invention, the fibers and fibrous articles will contain less than 10% by weight of said anti-blocking additives, based on the total weight of the fiber or fibrous article. For example, fibers and fibrous articles may contain less than 10% by weight of a pigment or filler. In other examples, the fibers and fibrous articles may contain less than 9% by weight, less than 5% by weight, less than 3% by weight, less than 1% by weight, and 0% by weight of a pigment or filler. , based on the total weight of the fiber. Colorants, sometimes referred to as organic coloring agents, can be added to impart a desired neutral hue and / or shine to the sulfopolyester. When colored fibers are desired, pigments or dyes may be included in the sulfopolyester reaction mixture during the reaction of the diol monomer and the dicarboxylic acid monomer or they may be melt blended with the preformed sulfopolyester. A preferred method of including colorants is to use a colorant having thermally stable colored organic compounds, which has reaction groups such that the colorant is copolymerized and incorporated into the sulfopolyester to enhance its hue. For example, colorants such as dyes possessing reactive carboxyl and / or hydroxyl groups, including, but not limited to, red and blue substituted anthraquinones, can be copolymerized in the polymer chain. When dyes are used as colorants, they can be added to the copolyester reaction process after the ester exchange or direct esterification reaction.

For the purposes of the present disclosure, the term fiber refers to a high aspect ratio polymeric body capable of being formed into two- or three-dimensional articles such as woven or non-woven cloth. In the context of the present invention, the term fiber is synonymous with fibers and is intended to refer to one or more fibers. The fibers described herein can be unicomponent, bicomponent, or multicomponent fibers. The term "unicomponent fiber," as used herein, is intended to refer to fiber prepared by melt spinning a single sulfopolyester, mixtures of one or more sulfopolyesters, or mixtures of one or more sulfopolyesters with one. or more additional polymers and includes short, monofilament and multifilament fibers. It is intended that

ES 2 403 114 T3 unicomponent is synonymous with the term multicomponent and includes bicomponent or multicomponent fibers, and refers to fibers that have been formed from at least two polymers extruded from the same extrusion device in the form of a mixture. The unicomponent or bicomponent fibers do not have the different polymer components arranged in different zones located relatively constantly throughout a cross-sectional area of ​​the fiber, and the different polymers are not normally continuous throughout the entire length of the fiber. fiber length, but normally form fibrils or protofibrils that start and end randomly. Thus, the term unicomponent is not intended to exclude fibers formed from a polymer or mixtures of one or more polymers to which are added small amounts of additives for coloring, anti-static properties, lubrication, hydrophilic nature, etc.

Rather, the term "multicomponent fiber," as used herein, is intended to refer to a fiber prepared by melting two or more fiber-forming polymers in separate extrusion devices and directing the polymer streams. multiple resultants within a spinneret with a plurality of distribution flow paths but spun together to form a fiber. Multicomponent fibers are sometimes also referred to as conjugate or bicomponent fibers. The polymers are arranged in distinct zones or segments located substantially constantly across the cross-section of the conjugate fibers and extending continuously along the length of the conjugate fibers. The configuration of said multicomponent fiber can be, for example, a shell / core configuration in which one polymer is surrounded by another or it can be a side-by-side configuration, a pie configuration or an island configuration in the sea. For example, a multicomponent fiber can be prepared by extruding the sulfopolyester and one or more non-water dispersible polymers separately, through a spinneret having a shaped or studied cross-sectional geometry such as, for example, a configuration of islands in the sea or segmented pie. Typically, multicomponent fibers are short, monofilament or multifilament fibers that have a rounded or shaped cross section. Most forms of fibers are suitable for heat setting. Fiber can include various antioxidants, pigments, and additives as described herein.

Generally, monofilament fibers range in size from about 15 to about 8000 denier per filament (abbreviated herein as d / f). Typically, the inventors' novel fibers will have d / f values ​​in the range of about 40 to about 5000. Monofilaments can be in the form of unicomponent or multicomponent fibers. Preferably, the monofilament fibers range in size from about 1.5 microns for melt blown webs, from about 0.5 to about 50 d / f for short fibers, and up to about 5000 d / f for monofilament fibers. Multifilament fibers in the form of crimped or non-crimped yarns and tow can also be used. Fibers used in melt blown web and melt spun cloth can be produced in microdenier sizes. The term microdenier, as used herein, is intended to refer to a d / f value of 1 d / f or less. For example, microdenier fibers will typically have d / f values ​​of 1 or less, 0.5 or less, or 0.1 or less. Nanofibers can also be produced by electrostatic spinning.

As discussed above, sulfopolyesters are also advantageous for the preparation of bicomponent and multicomponent fibers having a shaped cross section. The inventors have found that sulfopolyesters or mixtures of sulfopolyesters having a glass transition temperature (Tg) of at least 57 ° C are particularly useful for multicomponent fibers in order to avoid fiber blocking and melting during spinning and catching. Described herein is a multicomponent fiber having a shaped cross section comprising:

(A) a water dispersible sulfopolyester having a glass transition temperature (Tg) of at least 57 ° C, the sulfopolyester comprising:

(i) residues of one or more dicarboxylic acids;

(ii) from about 4 to about 40 mole%, based on total repeat units, of residues of at least one sulfomonomer having 2 functional groups and one or more sulfonate groups attached to an aromatic or cycloaliphatic ring in which the functional groups are hydroxyl, carboxyl groups or a combination thereof;

(iii) one or more diol residues in which at least 25% by mole, based on total diol residues, is a poly (ethylene glycol) having a structure

H- (OCH2-CH2) n-OH where n is an integer within the range of 2 to 500;

(iv) from 0 to about 25% by mole, based on total repeat units, of residues of a branching monomer having 3 or more functional groups in which the functional groups are hydroxyl, carboxyl, or a combination thereof; Y

ES 2 403 114 T3 (B) a plurality of segments comprising one or more non-water dispersible polymers immiscible with the sulfopolyester, wherein the segments are substantially isolated from each other by means of the sulfopolyester intervening between the segments;

wherein the fiber is island-in-the-sea or segmented pie cross-section and contains less than 10% by weight of a pigment or filler, based on the total weight of the fiber.

The dicarboxylic acids, diols, sulfopolyester, sulfomonomers, and branching monomer residues are as previously described. For multicomponent fibers, it is advantageous for the sulfopolyester to have a Tg of at least 57 ° C. Other examples of glass transition temperatures that the sulfopolyester or sulfopolyester blend of our multicomponent fiber may exhibit are at least 60 ° C, at least 65 ° C, at least 70 ° C, at least 75 ° C, at least 80 ° C, at least 85 ° C and at least 90 ° C. Furthermore, to obtain a sulfopolyester with a Tg of at least 57 ° C, mixtures of one or more sulfopolyesters in varying proportions can be used to obtain a mixture of sulfopolyesters having the desired Tg. The Tg of the sulfopolyester blend can be calculated using a weighted average of the Tg values ​​of the sulfopolyester components. For example, a sulfopolyester having a Tg of 48 ° C in a weight: weight ratio of 25:75 can be mixed with another sulfopolyester having a Tg of 65 ° C to give a blend of sulfopolyesters having a Tg of about 61 ° C.

In another embodiment, the water dispersible sulfopolyester component of the multicomponent fiber exhibits properties that allow for at least one of the following:

(A) that the multicomponent fibers are spun to a desired low denier value, (B) that the sulfopolyester of these multicomponent fibers is resistant to withdrawal during hydro-entanglement of a web formed from fibers but is removed effectively at elevated temperatures after hydroentangling, and (C) that the multicomponent fibers are suitable for heat setting to result in a strong and stable cloth. Surprising and unexpected results were obtained in promoting these objectives using a sulfopolyester having certain melt viscosity and sulfomonomer residue level.

Thus, in the present embodiment, a multicomponent fiber is provided having a shaped cross section comprising:

(A) at least one water dispersible sulfopolyester; and (B) a plurality of domains comprising one or more non-water dispersible polymers immiscible with the sulfopolyester, wherein said domains are substantially isolated from each other by means of the intervening sulfopolyester, wherein the fiber has a denier in spun form of less than about 6 denier per filament;

wherein the water dispersible sulfopolyesters exhibit a melt viscosity of less than about 12,000 poise measured at 240 ° C at a stress rate of 1 rad / s, and wherein the sulfopolyester comprises less than about 25 mole% of residues of at least one sulfomonomer, based on the total moles of diacid or diol residues.

Generally, the sulfopolyester used in the present multicomponent fibers has a melt viscosity of less than about 12,000 poise. Preferably, the melt viscosity of the sulfopolyester is less than 10,000 poise, more preferably less than 6,000 and most preferably less than 4,000 poise measured at 240 ° C and 1 rad / s shear rate. In another aspect, the sulfopolyester exhibits a melt viscosity of between about 1000-12000 poise, more preferably between 2000-6000 poise and most preferably between 2500-4000 poise measured at 240 ° C and 1 rad / s rate of flow. shear. Before determining the viscosity, the samples are dried at 60 ° C in a vacuum oven for 2 days. Melt viscosity is measured on a rheometer using a 25mm diameter parallel plate geometry with a 1mm spatial fit. A dynamic frequency scan is operated at a strain rate of 1 to 400 rad / s and 10% strain amplitude. Subsequently, the viscosity is measured at 240 ° C and a stress rate of 1 rad / s.

Generally, the level of sulfomonomer residues of the sulfopolyester polymers for use in accordance with the present aspect is less than about 25% by moles, and preferably, less than 20% by moles, presented as a percentage of the total diacid and diol residues of the sulfopolyester. More preferably, this level is between about 4 and about 20% by mole, even more preferably between about 5 and about 12% by mole, and most preferably between about 7 and about 10% by mole. Preferably, the sulfomonomers for use in the invention have 2 functional groups and one or more sulfonate groups attached to an aromatic or cycloaliphatic ring.

ES 2 403 114 T3 in which the functional groups are hydroxyl, carboxyl or a combination thereof. The sodium sulpho-isophthalic acid monomer is particularly preferred.

In addition to the sulfomonomer described above, preferably the sulfopolyester comprises residues of one or more dicarboxylic acids, one or more diol residues in which at least 25% by mole, based on the total diol residues, is poly (ethylene glycol) having the structure

H- (OCH2-CH2) n-OH where n is an integer in the range of 2 to 500, and 0 to 20% by mole, based on total repeat units, of residues of a branching monomer having 3 or more functional groups in which the functional groups are hydroxyl, carboxyl, or a combination thereof.

In a particularly preferred embodiment, the sulfopolyester comprises from about 80-96 mole% dicarboxylic acid residues, from about 4 to about 20 mole% sulfomonomer residues, and 100 mole% diol residues (the% being 200% in total moles, that is, 100% in moles of diacid and 100% in moles of diol). More specifically, the dicarboxylic part of the sulfopolyester comprises between about 60-80 mole% terephthalic acid, about 0-30 mole% isophthalic acids, and about 4-20 mole% 5-sodium sulfoisophthalic acid (5-SSIPA ). The diol part comprises from about 0-50% by mole of diethylene glycol and from about 50-100% by mole of ethylene glycol. An exemplary formulation according to the present embodiment is explained below.

<td></td><td>Approximate Mole% (based on total moles of diol and diacid residues)</td>

<td>Terephthalic acid</td><td> 71</td>

<td>Isophthalic Acid</td><td> 20</td>

<td>5-SSIPA</td><td> 9</td>

<td>Diethylene glycol</td><td> 35</td>

<td>Ethylene glycol</td><td> 65</td>

The non-water dispersible component of the multicomponent fiber may comprise any of the non-water dispersible polymers described herein. Fiber spinning can also occur according to any method described herein. However, the improved rheological properties of multicomponent fibers in accordance with the present aspect of the invention provide for improved extraction rates. When the sulfopolyester and the non-water dispersible polymer are extruded to produce extruded multicomponent fractions, the extruded multicomponent fraction is suitable for melt extraction to produce the multicomponent fiber, using any of the methods described in herein, at a speed of at least about 2000 m / min, more preferably at least about 3000 m / min, even more preferably at least about 4000 m / min, and most preferably at least about 4500 m / min. Without wishing to be bound by theory, extraction of the multicomponent fractions subjected to extraction at these rates results in at least oriented crystallinity of the non-water dispersible component of the multicomponent fiber. This oriented crystallinity can increase the dimensional stability of nonwovens prepared from multicomponent fibers during subsequent processing.

Another advantage of the extruded multicomponent fraction is that it can be melt extracted to give a multicomponent fiber having a denier in spun form of less than 6 denier per filament. Other multi-component fiber size ranges include a denier in spun form of less than 5 denier per filament and less than 2.5 denier per filament.

Thus, in another embodiment, an extruded multicomponent fraction having a shaped cross section, comprising:

(A) at least one water dispersible sulfopolyester; and (B) a plurality of domains comprising one or more non-water dispersible polymers immiscible with the sulfopolyester, wherein the domains are substantially isolated from each other by means of the intervening sulfopolyester, wherein the fraction subjected Extrusion is suitable to be extracted in melt at a speed of at least approximately 2000 m / min.

The multicomponent fiber comprises a plurality of segments or domains of one or more non-water dispersible polymers immiscible with the sulfopolyester in which the segments or domains are substantially

ES 2 403 114 T3 isolated from each other by means of the sulfopolyester intervening between the segments or domains. The term "substantially isolated", as used herein, is intended to mean that the segments or domains are separated from each other to allow the segment domains to form individual fibers upon removal of the sulfopolyester. For example, the segments or domains may be touching each other, eg, in a segmented pie configuration but may separate by impact or when the sulfopolyester is removed.

The weight ratio of the sulfopolyester to the non-water dispersible polymer component in the multicomponent fiber is generally within the range of about 60:40 to about 2:98 or, in another example, within the range of about 50: 50 to approximately 5:95. Typically, the sulfopolyester comprises 50% by weight or less of the total weight of the multicomponent fiber.

The segments or domains of the multicomponent fiber may comprise one or more non-water dispersible polymers. Examples of non-water dispersible polymers that can be used in multicomponent fiber segments include, but are not limited to, polyolefins, polyesters, polyamides, polylactides, polycaprolactone, polycarbonate, polyurethane, cellulose ester, and polyvinyl chloride. . For example, the non-water dispersible polymer can be a polyester such as polyethylene terephthalate, poly (butylene terephthalate), poly (cyclohexylene cyclohexanedicarboxylate), poly (cyclohexene terephthalate), poly (trimethylene terephthalate) and Similar. In another example, the non-water dispersible polymer may be suitable for bio-disintegration as determined by DIN Standard 54900 and / or biodegradable as determined by ASTM D6340-98 Standard Method. Examples of biodegradable polyesters and polymer blends are described in US Patent Nos. 5,599,858; 5,580,911; 5,446,079 and 5,559,171. The term biodegradable, as used herein in reference to the non-water dispersible polymers used in the present invention, is understood to mean that the polymers degrade under environmental influences such as, for example, in the composting environment, in an appropriate and demonstrable span of time as defined, for example, by ASTM D6340-98 Standard Method, entitled Standard Test Methods for Determining Aerobic Biodegradation or Radiolabeled Plastic Materials in an Aqueous or Compost Environment. The non-water dispersible polymers used in the present invention may also be suitable for biodisintegration, which means that the polymers are easily fragmented in a composting environment as defined, for example, by DIN Standard 54900. For example, the molecular weight of the polymer in the environment is initially reduced by the action of heat, water, air, microbes, and other factors. This reduction in molecular weight results in a loss of physical properties (toughness) and often fiber breakage. Once the molecular weight of the polymer is low enough, then the monomers and oligomers are assimilated by the microbes. In an aerobic environment, these monomers and oligomers are ultimately oxidized to CO2, H2O, and new cellular biomass. In an aerobic environment, the monomers or oligomers are ultimately converted into CO2, H2, acetate, methane, and cellular biomass.

For example, the non-water dispersible polymer can be an aliphatic-aromatic polyester, abbreviated herein as AAPE. The term "aliphatic-aromatic polyester" as used herein means a polyester comprising a mixture of residues of cycloaliphatic or aliphatic diols or dicarboxylic acids and aromatic diols or dicarboxylic acids. The term "non-aromatic," as used herein, with respect to the dicarboxylic acid and diol monomers used in the present invention, means that the carboxyl or hydroxyl groups of the monomer are not connected through the aromatic nucleus. For example, adipic acid does not contain an aromatic nucleus in its main chain, that is, the chain of carbon atoms connecting the carboxylic acid groups is therefore non-aromatic. In contrast, the term aromatic means that the diol or dicarboxylic acid contains an aromatic nucleus in the main chain such as, for example, terephthalic acid or 2,6-naphthalene dicarboxylic acid. Non-aromatic is therefore intended to include both aliphatic and cycloaliphatic structures such as, for example, diols and dicarboxylic acids, which contain as a backbone a straight or branched chain or a cyclic configuration of the constituent carbon atoms which may be saturated or paraffinic in nature, unsaturated, that is, containing non-aromatic carbon-carbon double bonds, or acetylenic, that is, containing carbon-carbon triple bonds. Thus, in the context of the description and claims of the present invention, non-aromatic is intended to include straight and branched chain structures (referred to herein as aliphatic and cyclic structures (referred to herein as alicyclic). or cycloaliphatic). However, the term "non-aromatic" is not intended to exclude any aromatic substituents that may be attached to the backbone of an aliphatic or cycloaliphatic dicarboxylic acid or diol. In the present invention, typically, the difunctional carboxylic acid is a dicarboxylic acid such as, for example, adipic acid, or an aromatic dicarboxylic acid such as, for example, terephthalic acid. The difunctional hydroxyl compound can be a cycloaliphatic diol such as, for example, 1,4-cyclohexanedimethanol, a linear or branched aliphatic diol such as, for example, 1,4-butanediol, or an aromatic diol such as, for example, hydroquinone.

The AAPE may be a linear or branched random copolyester and / or an extended chain copolyester comprising diol residues comprising the residues of one or more linear or branched, substituted or unsubstituted diols, selected from aliphatic diols containing from 2 to 8 carbon atoms, polyalkylene ether glycols containing from 2 to 8 carbon atoms, and cycloaliphatic diols containing from about 4 to about 12 carbon atoms. Typically, substituted diols will comprise from 1 to about 4 substituents that are independently selected from halo, C6-C10 aryl, and alkoxy.

ES 2 403 114 T3

C1-C4. Examples of diols that can be used include, but are not limited to, ethylene glycol, diethylene glycol, propylene glycol,

1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, polyethylene glycol, diethylene glycol, 2,2, 4-trimethyl-1,6-hexanediol, thiodiethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, triethylene glycol, and tetraethylene glycol with preferred diols comprising one or more diols selected from 1,4-butanediol; 1,3-propanediol; ethylene glycol; 1,6-hexanediol; diethylene glycol; or 1,4-cyclohexanedimethanol. The AAPE also comprises diacid residues containing from about 35 to about 99 mole%, based on the total moles of diacid residues, of the residues of one or more selected non-aromatic, linear or branched, substituted or unsubstituted dicarboxylic acids. between aliphatic dicarboxylic acids containing from 2 to about 12 carbon atoms and cycloaliphatic acids containing from about 5 to about 10 carbon atoms. Typically, substituted non-aromatic dicarboxylic acids will contain from 1 to about 4 substituents selected from halo, C6-C10 aryl, and C1-C4 alkoxy. Non-limiting examples of non-aromatic diacids include malonic, succinic, glutaric, adipic, pimelic, azelaic, sebacic, fumaric, 2,2-dimethyl glutaric, suberic, 1,3-cyclopentanedicarboxylic, 1,4-cyclohexanedicarboxylic, 1,3-cyclohexanedicarboxylic, diglycolic , itaconic, maleic and

2,5-norbornan-dicarboxylic. In addition to the non-aromatic dicarboxylic acids, AAPE comprises from about 1 to about 65 mole%, based on the total moles of diacid residues, of the residues of one or more substituted or unsubstituted aromatic dicarboxylic acids containing from 6 to about 10 carbon atoms. In the case where substituted aromatic dicarboxylic acids are used, they will typically contain 1 to about 4 substituents selected from halo, C6-C10 aryl, and C1C4 alkoxy. Non-limiting examples of aromatic dicarboxylic acids that can be used in EPAs used in the present invention are terephthalic acid, isophthalic acid, salts of 5-sulfoisophthalic acid and 2,6-naphthalene dicarboxylic acid. More preferably, the non-aromatic dicarboxylic acid will comprise adipic acid, the aromatic dicarboxylic acid will comprise terephthalic acid, and the diol will comprise 1,4-butanediol.

Other possible compositions for the EPAs used in the invention are those prepared from the following diols and dicarboxylic acids (or their polyester-forming equivalents such as diesters) in the following molar percentages, based on 100 mole% of a diacid component and 100% by mole of a diol component:

(1) glutaric acid (from about 30 to about 75%); terephthalic acid (from about 25 to about 70%); 1,4-butanediol (from about 90 to 100%); and a modifying diol (0 to about 10%);

(2) succinic acid (from about 30 to about 95%); terephthalic acid (from about 5 to about 70%); 1,4-butanediol (from about 90 to about 100%); and a modifying diol (0 to about 10%); and (3) adipic acid (from about 30 to about 75%); terephthalic acid (from about 25 to about 70%); 1,4-butanediol (from about 90 to 100%); and a modifying diol (0 to about 10%).

Preferably the modifying diol is selected from 1,4-cyclohexanedimethanol, triethylene glycol, polyethylene glycol and neopentyl glycol. The most preferred EPAEs are straight or branched chain extended copolyesters comprising from about 50 to about 60% by mole of adipic acid residues, from about 40 to about 50% by moles of terephthalic acid residues, and at least 95% in moles of 1,4-butanediol residues. Even more preferably, the adipic acid residues comprise from about 55 to about 60% by mole, the terephthalic acid residues comprise from about 40 to about 45% by mole, and the diol residues comprise about 95% of 1,4 residues. -butanediol. Such compositions are commercially available under the EASTAR BIO® copolyester trade name from Eastman Chemical Company, Kingsport, TN and under the ECOFLEX® trade name from BASF Corporation.

Additionally, specific examples of preferred AAPEs include a poly (tetramethylene co-terephthalate glutarate) containing (a) 50 mole% glutaric acid residues, 50 mole% terephthalic acid residues and 100 mole% 1,4-butanediol residues, (b) 60 mol% glutaric acid residues, 40 mol% terephthalic acid residues, 100 mol% 1,4-butanediol residues or (c) 40 mol% moles of glutaric acid residues, 60 mol% terephthalic acid residues and 100 mol% 1,4-butanediol residues; a poly (tetramethylene co-terephthalate succinate) containing (a) 85 mol% succinic acid residues, 15 mol% terephthalic acid residues and 100 mol% 1,4-butanediol residues or (b ) 70 mol% of succinic acid residues, 30 mol% of terephthalic acid residues, and 100 mol% of 1,4-butanediol residues; a poly (ethylene co-terephthalate succinate) containing 70 mol% succinic acid residues, 30 mol% terephthalic acid residues and 100 mol% ethylene glycol residues; and poly (tetramethylene co-terephthalate adipate) containing (a) 85 mol% adipic acid residues, 15 mol% terephthalic acid residues and 100 mol% 1,4-butanediol residues; or (b) 55 mol% adipic acid residues, 45 mol% terephthalic acid residues, and 100 mol% 1,4-butanediol residues.

ES 2 403 114 T3

Preferably, the AAPE comprises from about 10 to about 1,000 repeat units, and preferably, from about 15 to about 600 repeat units. The AAPE can have an inherent viscosity of from about 0.4 to about 2.0 dL / g or more preferably from

0.7 to about 1.6 dL / g, measured at a temperature of 25 ° C, using a concentration of 0.5 grams of polyester in 100 ml of a 60/40 by weight solution of phenol / tetrachloroethane.

Optionally, the AAPE may contain the residues of a branching agent. The mole percent ranges of the branching agent are from about 0 to about 2 mole%, preferably from about 0.1 to about 1 mole%, and most preferably from about 0.1 to about 0.5%. in moles, based on the total moles of diol or diacid residues (depending on whether the branching agent contains carboxyl or hydroxyl groups). Preferably, the branching agent has an average molecular weight of from about 50 to about 5000, more preferably from about 92 to about 3000, and a functionality of from about 3 to about 6. The branching agent, for example, can be the esterified residue of a polyol having 3 to 6 hydroxyl groups, a poly (carboxylic acid) having 3 or 4 carboxyl groups (or equivalent ester-forming groups), or a hydroxy acid. having a total of 3 to 6 hydroxyl and carboxyl groups. In addition, AAPE can be branched through the addition of a peroxide during reactive extrusion.

Each segment of the non-water dispersible polymer can be different from others in fineness and can be arranged with any shaped or studied cross-sectional geometry known to those skilled in the art. For example, a sulfopolyester and a non-water dispersible polymer can be used to prepare a bi-component fiber having a geometry under technical study such as, for example, side-by-side configurations, islands in the sea, segmented pie , other separable configurations, shell / core or other configurations known to those skilled in the art. Other multi-component configurations are also possible. Subsequent removal from one side, the sea, or another part of the cake can result in very fine fibers. The process of preparing bicomponent fibers is also well known to those skilled in the art. In a bicomponent fiber, the sulfopolyester fibers may be present in amounts of from about 10 to about 90% by weight and will generally be used in the sheath portion or sheath / core fibers. Typically, when a water insoluble or non-water dispersible polymer is used, the resulting bicomponent or multicomponent fiber is not completely water dispersible. Side-by-side combinations with significant differences in thermal shrinkage can be used to develop a spiral curl. If crimping is desired, a sawtooth crimp or stuffing box is generally appropriate for many applications. If the second component is in the core of the shell / core configuration, that core can be optionally stabilized.

Sulfopolyesters are particularly useful for fibers that have an island-in-the-sea or segmented pie cross-section as they only require dispersion of a neutral or slightly acidic substance (i.e. soft water), compared to solutions containing caustic soda. which sometimes require the removal of other water dispersible polymers from the multicomponent fibers. The term "soft water" as used in the present disclosure means that the water has up to 5 grains per gallon (3.79 liters) of CaCO3 (1 grain of CaCO3 per gallon is equivalent to 17.1 ppm). Thus, another aspect described herein is a multicomponent fiber, comprising:

(A) a water dispersible sulfopolyester having a glass transition temperature (Tg) of at least 57 ° C, the sulfopolyester comprising:

(i) from about 50 to about 96% by mole of one or more isophthalic acid or terephthalic acid residues, based on the total acid residues;

(ii) from about 4 to about 30 mole%, based on total acid residues, of a sodium sulfoisophthalic acid residue;

(iii) one or more diol residues in which at least 25% by mole, based on the total diol residues, is a poly (ethylene glycol) having the structure

H- (OCH2-CH2) n-OH where n is an integer within the range of 2 to about 500;

(iv) from 0 to about 20% by mole, based on total repeat units, of residues of a branching monomer having 3 or more functional groups in which the functional groups are hydroxyl, carboxyl, or a combination thereof; and (B) a plurality of segments comprising one or more non-water dispersible polymers immiscible with the sulfopolyester, wherein the segments are substantially isolated from one another by means of the sulfopolyester intervening between the segments;

ES 2 403 114 T3 in which the fiber has an island-in-the-sea or segmented pie cross-section and contains less than 10% by weight of a pigment or filler, based on the total weight of the fiber.

Dicarboxylic acids, diols, sulfopolyester, sulfomonomers, branching monomer residues, and non-water dispersible polymers are as previously described. For multicomponent fibers, it is advantageous for the sulfopolyester to have a Tg of at least 57 ° C. The sulfopolyester can be a single sulfopolyester or a blend of one or more sulfopolyester polymers. Other examples of glass transition temperatures that can be exhibited by sulfopolyester or sulfopolyester blends are at least 65 ° C, at least 70 ° C, at least 75 ° C, at least 85 ° C, and at least 90 ° C. For example, the sulfopolyester may comprise from about 75 to about 96% by mole of one or more isophthalic acid or terephthalic acid residues and from about 25 to about 95% by mole of a diethylene glycol residue. As described above examples of non-water dispersible polymers are polyolefins, polyesters, polyamides, polylactides, polycaprolactones, polycarbonates, polyurethanes, cellulose esters and polyvinyl chlorides. In addition, the water dispersible polymer can be biodegradable or capable of disintegration. For example, the non-water dispersible polymer can be an aliphatic-aromatic polyester as described above.

The multicomponent fiber can be prepared by any number of methods known to the person skilled in the art. The present disclosure thus provides a process for a multicomponent fiber having a shaped cross section comprising; spinning a water dispersible sulfopolyester having a glass transition temperature (Tg) of at least 57 ° C and one or more non-water dispersible polymers immiscible with the sulfopolyester into a fiber, the sulfopolyester comprising:

(i) residues of one or more dicarboxylic acids;

(ii) from about 4 to about 40 mole%, based on total repeat units, of residues of at least one sulfomonomer having 2 functional groups and one or more sulfonate groups attached to an aromatic or cycloaliphatic ring in which functional groups are hydroxyl, carboxyl, or a combination thereof;

(iii) one or more diol residues in which at least 25% by mole, based on total diol residues, is a poly (ethylene glycol) having a structure

H- (OCH2-CH2) n-OH where n is an integer within the range of 2 to about 500; and (iv) from 0 to about 25% by mole, based on total repeat units, of residues of a branching monomer having 3 or more functional groups in which the functional groups are hydroxyl, carboxyl, or a combination thereof. ; and wherein the fiber has a plurality of segments comprising the non-water dispersible polymers and the segments are substantially isolated from one another by means of the sulfopolyester intervening between the segments and the fiber contains less than 10% by weight of a pigment or filler, based on the total weight of the fiber. For example, the multi-component fiber can be prepared by melting the sulfopolyester and one or more non-water dispersible polymers in separate extrusion devices and directing the individual polymer streams into an extrusion die or die with a plurality of distribution flow paths, such that the non-water dispersible polymer component forms small segments or fine strands which are substantially isolated from one another by means of the intervening sulfopolyester. The cross section of said fiber can be, for example, a segmented pie configuration or an island configuration in the sea. In another example, the sulfopolyester and one or more non-water-dispersible polymers are fed separately into the holes in the spinneret and subsequently extruded in a shell-core form in which the non-water-dispersible polymer forms a shell that it is substantially enclosed by the sulfopolyester shell polymer. In the case of such concentric fibers, the hole supplying the core polymer is located in the center of the spinning hole outlet and the conditions of the core polymer fluid are strictly controlled in order to maintain the concentric nature of both. components when spinning occurs. The modifications in the hole of the spinneret allow to obtain different forms of core and / or cover within the cross section of the fiber. In another example, the multicomponent fiber having a side-to-side cross-section or configuration can be produced by co-extruding the water-dispersible sulfopolyester and the non-water-dispersible polymer through the holes separately and causing the separate polymer streams converge at substantially the same rate to coalesce side by side as a combined stream below the face of the spinneret; or (2) feeding the two polymeric streams separately through the holes, which converge on the surface of the spinneret, at substantially the same speed to join side by side as a combined stream on the surface of the spinneret. In both cases, the speed of each polymer stream, at the junction point, is determined by measuring the pumping speed, the number of orifices, and the orifice size.

Dicarboxylic acids, diols, sulfopolyester, sulfomonomers, branching monomer residues, and non-water dispersible polymers are as previously described. The sulfopolyester has a transition temperature

ES 2 403 114 T3 vitreous of at least 57 ° C. Other examples of glass transition temperatures that the sulfopolyester or mixture of sulfopolyesters may exhibit are at least 65 ° C, at least 70 ° C, at least 75 ° C, at least 85 ° C, and at least 90 ° C. In one example, the sulfopolyester may comprise from about 50 to about 96 mole% of one or more isophthalic acid or terephthalic acid residues, based on total acid residues; and from about 4 to about 30 mole%, based on total residues, of a sodium isophthalic acid residue; and from 0 to about 20% by mole, based on total repeating units, of residues of a branching monomer having 3 or more functional groups in which the functional groups are hydroxyl, carboxyl, or a combination thereof. In another example, the sulfopolyester may comprise from about 75 to about 96 mole% of one or more isophthalic acid or terephthalic acid residues and from about 25 to about 95 mole% of an ethylene glycol residue. As discussed above, examples of non-water dispersible polymers are polyolefins, polyesters, polyamides, polylactides, polycaprolactone, polycarbonate, polyurethane, and polyvinyl chloride. Furthermore, the non-water dispersible polymer may be biodegradable or susceptible to bio-disintegration. For example, the non-water dispersible polymer can be an aliphatic-aromatic polyester as described above. Examples of shaped cross sections include, but are not limited to, island-in-the-sea, side-by-side, shell-core, or segmented cake configurations.

In another embodiment, a process is provided for preparing a multicomponent fiber having a shaped cross section comprising: spinning at least one water-dispersible sulfopolyester and one or more non-water-dispersible polymers immiscible with the sulfopolyester to produce a multicomponent fiber, wherein the multicomponent fiber has a plurality of domains comprising the non-water-dispersible polymers and domains are substantially isolated from each other by means of the sulfopolyester intervening between the domains; wherein the water dispersible sulfopolyester exhibits a melt viscosity of less than about 12,000 poise measured at 240 ° C at a stress rate of 1 rad / s, and wherein the sulfopolyester comprises less than about 25 mole% of residues of at least one sulfomonomer, based on the total moles of diacid or diol residues; and wherein the multicomponent fiber has a denier value in spun form of less than about 6 denier per filament.

The sulfopolyester used in the present multicomponent fibers and the water dispersible polymers have been discussed previously in the present disclosure.

In another embodiment, a process is provided for preparing a multicomponent fiber having a cross section comprising:

(A) extruding at least one water-dispersible sulfopolyester and one or more non-water-dispersible polymers immiscible with said sulfopolyester to produce an extruded multi-component fraction, wherein the extruded multi-component fraction has a plurality of domains that comprise the non-water dispersible polymers and the domains are found substantially isolated from each other by means of sulfopolyester intervening between the domains; and (B) melt extracting the extruded multicomponent fraction at a speed of at least about 2000 m / min to produce the multicomponent fiber.

It is also a feature of the present embodiment that the process includes the step of melt extracting the extruded multicomponent fraction at a speed of at least about 2000 m / min, more preferably, at least about 3000 m / min, and most preferably at least 4500 m / min.

Typically, upon exit from the spinneret, the fibers are inactivated with a cross flow of air once the fibers solidify. Various finishes and sizes can be applied to the fiber at this stage. Typically, the fibers are subsequently drawn and wound onto a take-up reel. Other additives can be incorporated into the finish in effective amounts such as emulsifiers, antistatics, antimicrobials, antifoams, lubricants, heat stabilizers, UV stabilizers, and the like.

Optionally, the extracted fibers can be textured and wound to form a bulky continuous filament. This one-step technique is known as draw-spin texturing in the art. Other embodiments include flat filament yarns (not textured), or a staple fiber, either crimped or not crimped.

Subsequently, the sulfopolyester can be removed by dissolving the interfacial layers or pie segments and leaving the smaller filaments or microdenier fibers of the non-water dispersible polymer (s). Thus, the invention provides microdenier fibers comprising:

(A) spinning a water dispersible sulfopolyester having a glass transition temperature (Tg) of at least 57 ° C and one or more non-water dispersible polymers immiscible with the sulfopolyester to give multicomponent fibers, the sulfopolyester comprising:

(i) from about 50 to about 96% by mole of one or more isophthalic acid or terephthalic acid residues, based on the total acid residues;

ES 2 403 114 T3 (ii) from about 4 to about 30% by mole, based on total acid residues, of a sodium isophthalic acid residue;

(iii) one or more diol residues in which at least 25% by mole, based on the total diol residues, is a poly (ethylene glycol) having the structure

H- (OCH2-CH2) n-OH where n is an integer within the range of 2 to about 500; and (iv) from 0 to about 20% by mole, based on total repeating units, of residues of a branching monomer having 3 or more functional groups in which the functional groups are hydroxyl, carboxyl, or a combination thereof. ;

wherein the fibers have a plurality of segments comprising the non-water dispersible polymers wherein the segments are substantially isolated from each other by means of the sulfopolyester intervening between the segments and the fibers contain less than about 10% by weight of a pigment or filler, based on the total weight of the fibers;

^Y (B) contacting the multicomponent fibers with water to remove the sulfopolyester, thereby forming the microdenier fibers.

Typically, the multicomponent fiber is contacted with water at a temperature of from about 25 ° C to about 100 ° C, preferably from about 50 ° C to about 80 ° C, for a period of time from about 10 to about 600 seconds. , in which the sulfopolyester dissipates or dissolves. Upon removal of the sulfopolyester, typically the remaining non-water dispersible polymer microfibers will have an average fineness of 1 d / f or less, typically 0.5 d / f or less, or more typically 0.1 d / f or less. . Typical applications for these non-water dispersible microfibers include nonwoven cloths, such as, for example, artificial leathers, chamois, wipes, and filter media. Filter media produced from these microfibers can be used to filter air or liquids. Liquid filtration media include, but are not limited to, water, body fluids, solvents, and hydrocarbons.

In another embodiment of the present invention, there is provided a process for preparing microdenier fibers comprising spinning at least one water dispersible sulfopolyester and one or more non-water dispersible polymers immiscible with the water dispersible sulfopolyester to give multicomponent fibers. , wherein said multicomponent fibers have a plurality of domains comprising said non-water dispersible polymers wherein the domains are substantially isolated from one another by means of the sulfopolyester intervening between the domains; wherein the fibers have a denier in spun form of less than about 6 denier per filament; wherein the water dispersible sulfopolyester exhibits a melt viscosity of less than about 12,000 poise measured at 240 ° C at a stress rate of 1 rad / s, and wherein the sulfopolyester comprises less than about 25 mole% of the residues of at least one sufomonomer, based on the total moles of diacid or diol residues; and contacting the multicomponent fibers with water to remove the water dispersible sulfopolyester, thereby forming microdenier fibers.

In another embodiment of the invention, a process for preparing microdenier fibers is provided comprising:

(A) extruding at least one water dispersible sulfopolyester and one or more non-water dispersible polymers immiscible with said water dispersible sulfopolyester to produce extruded multicomponent fractions, wherein said extruded multicomponent fractions have a plurality of domains comprising said non-water dispersible polymers wherein said domains are substantially isolated from one another by means of said intervening sulfopolyester;

(B) melt extracting said extruded multicomponent fractions at a speed of at least about 2000 m / min to form multicomponent fibers; and (C) contacting said multicomponent fibers with water to remove said water dispersible sulfopolyester, thereby forming microdenier fibers.

It is preferable that melt extraction of the extruded multicomponent fractions at a speed of at least about 2000 m / min, more preferably at least about 3000 m / min, and most preferably at least 4500 m / min. min.

Such sulfomonomers and sulfopolyesters suitable for use in accordance with the invention have been described above.

Because the sulfopolyesters preferred for use in accordance with the present aspect of the invention are generally resistant to removal during subsequent hydro-crosslinking processes, it is preferable that the

ES 2 403 114 T3 water used to remove the sulfopolyester from multicomponent fibers is above room temperature, more preferably that the water is at least about 45 ° C, even more preferably at least 60 ° C and most preferably at least 80 ° C.

In another embodiment of the present invention, another process is provided for producing non-water dispersible polymer microfibers. The process comprises:

a) cutting a multicomponent fiber to produce chopped multicomponent fibers;

b) contacting the fiber-containing raw material with water to produce a fiber blend suspension; wherein the raw material containing said fibers comprises staple multicomponent fibers;

c) heating said fiber blend slurry to produce a hot fiber blend slurry;

d) optionally mixing said fiber blend suspension in a shear zone;

e) removing at least part of the sulfopolyester from said multicomponent fiber to produce a slurry mixture comprising a dispersion of sulfopolyester and the non-water dispersible polymer microfibers; Y

f) separating non-water dispersible polymer microfibers from said slurry mixture.

The multicomponent fiber can be cut to any length that can be used to produce nonwovens. In one embodiment of the invention, the multicomponent fiber is cut into lengths from about 1mm to about 3.5mm. In another aspect of the invention, the multicomponent fiber can be cut into a mixture of different lengths.

The fiber-containing raw material can comprise any other type of fiber that is useful in the production of nonwovens. In one embodiment, the fiber-containing raw material further comprises a fiber selected from the group consisting of cellulosic fiber pulp, glass fiber, polyester fibers, nylon fibers, polyolefin fibers, rayon fibers and ester fibers of cellulose.

The fiber-containing raw material is mixed with water to produce a fiber blend suspension. Preferably, in order to facilitate the removal of the water dispersible sulfopolyester, the water used can be soft water or deionized water. Soft water has been previously defined in the present description. In one embodiment of the present invention, at least one water softening agent can be used to facilitate removal of the water dispersible sulfopolyester from the multicomponent fiber. Any water softening agent known in the art can be used. In one embodiment, the water softening agent is a chelating agent or a calcium ion binding agent. Applicable chelating agents or calcium binding agents are compounds containing a plurality of carboxylic acid groups per molecule in which the carboxylic groups of the molecular structure of the chelating agent are separated by 2 to 16 atoms. Sodium ethylene diamine tetraacetic acid (EDTA) is an example of the most common chelating agent, containing four carboxylic acid moieties per molecular structure with a 3-atom spacing between adjacent carboxylic acid groups. The sodium salt of polyacrylic acid is an example of a calcium binding agent that contains carboxylic acid groups separated by two atoms between carboxylic groups. The sodium salts of maleic acid or succinic acid are examples of the more basic chelating agent compounds. Other examples of applicable chelating agents include compounds that have in common the presence of multiple carboxylic acid groups in the molecular structure in which the carboxylic acid groups are separated by the required distance (2 to 6 atomic units) which results in favorable steric interaction performance with di- or multi-valent cations such as calcium, which causes the chelating agent to preferentially bind di- or multi-valent cations. Such compounds include, but are not limited to, diethylenetriaminepentaacetic acid; diethyleneamino-N, N, N ', N', N-pentacetic acid; penthetic acid; N, N-bis (2- (bis (carboxymethyl) amino) ethyl) -glycine; diethylenetriamine pentaacetic acid; [[(carboxymethyl) imino] bis (ethylene nitrile)] -tetraacetic acid; edetic acid; ethylenedinitrilotetraacetic acid; EDTA, free base; EDTA, free acid; ethylenediaminoN, N, N'N, '-tetraacetic acid; hampreno; verseno; N, N'-1,2-ethane diylbis (N- (carboxymethyl) glycine); Ethylenediaminetetraacetic acid; N, N-bis (carboxymethyl) glycine; triglycolamic acid; trilone A; alpha, alpha ', alpha-trimethylaminotriccarboxylic acid; tri (carboxymethyl) amine; aminotriacetic acid; hampshire acid NTA; nitrile-2,2 ', 2-triacetic acid; titriplex i: nitriloacetic acid and its mixtures.

The amount of water softening agent needed depends on the hardness of the water used in terms of Ca⁺⁺ and other multivalent ions.

The fiber blend suspension is heated to produce a hot fiber blend suspension. The temperature is that which is sufficient to remove a part of the sulfopolyester from the multi-component fiber. In one embodiment of the invention, the fiber blend suspension is heated to a temperature ranging from about 50 ° C to about 100 ° C. Other temperature ranges are from about 70 ° C to about 100 ° C, from about 80 ° C to about 100 ° C, and from about 90 ° C to about 100 ° C.

ES 2 403 114 T3

Optionally, the fiber blend suspension is mixed in a shear zone. The amount of mixing is sufficient to disperse and remove a portion of the water-dispersible sulfopolyester from the multicomponent fiber and separate the non-water-dispersible polymer microfibers. In one embodiment of the invention, 90% of the sulfopolyester is removed. In another embodiment, 95% of the sulfopolyester is removed, and in another embodiment 98% or more of the sulfopolyester is removed. The shear zone can comprise any type of equipment that can provide the necessary shear action to disperse and remove a portion of the water-dispersible sulfopolyester from the multicomponent fiber and separate the non-water-dispersible polymer microfibers. Examples of such equipment include, but are not limited to, pulp treatment devices and refiners.

The water dispersible sulfopolyester of the multicomponent fiber, upon contact with water and heating, is dispersed and separated from the non-water dispersible polymer fiber to produce a slurry mixture comprising the dispersion of a sulfopolyester and the non-water dispersible polymer fibers. The non-water dispersible polymer microfibers can be subsequently separated from the sulfopolyester dispersion by any means known in the art. For examples, the slurry mixture can be conducted through separation equipment, such as, for example, screens and filters. Optionally, the non-water-dispersible polymer microfibers can be washed once or several times in order to remove more water-dispersible sulfopolyester.

Removal of the water dispersible sulfopolyester can be determined by physical observation of the slurry mixture. The water used to wash non-water-dispersible polymer microfibers is clear if the water-dispersible sulfopolyester has been largely removed. If the water-dispersible sulfopolyester is still being removed, the water used to wash the non-water-dispersible polymer microfibers may be milky. Also, if the water-dispersible sulfopolyester remains on the non-water-dispersible polymer microfibers, the microfibers can be quite tacky to the touch.

The water dispersible sulfopolyester can be recovered from the sulfopolyester dispersion by any method known in the art.

In accordance with the present invention, there is provided a non-water-dispersible polymer microfiber comprising at least one non-water-dispersible polymer wherein the non-water-dispersible polymer microfiber has an equivalent diameter of less than 5 microns and a length less than 3.5 millimeters. The non-water dispersible polymer microfiber is produced by the previously described processes for producing microfibers. In another aspect of the invention, the non-water dispersible polymer microfiber has an equivalent diameter of less than 3 microns and a length of less than 3.5 millimeters. In other embodiments of the invention, the non-water dispersible polymer microfiber has an equivalent diameter of less than 3 microns. The domains or segments of the multicomponent fiber, once separated, give rise to non-water dispersible polymer microfibers.

Described herein is a fibrous article comprising the water dispersible fiber, multicomponent fiber, microdenier fibers or non-water dispersible polymer microfibers described above. The term "fibrous article" is understood to mean any article having or resembling fibers. Non-limiting examples of fibrous articles include multifilament fibers, yarns, cords, tapes, cloths, wet warped nets, dry warped nets, melt blown nets, spunbonded nets, thermally bonded nets, hydro-entangled nets, nets. nonwovens and cloths and their combinations; goods having one or more layers of fibers, such as, for example, multilayer nonwovens, laminates, and composites such as fibers, gauze, bandages, diapers, toilet training pants, tampons, surgical dressings, and masks, sanitary napkins; and the like. A nonwoven article comprising the non-water dispersible polymer microfibers described hereinbefore is in accordance with the invention. In addition, non-water dispersible microfibers can be used in filter media for air filtration, liquid filtration, filtration for food preparation, filtration for medical applications, and paper and paper product manufacturing processes. Additionally, fibrous articles can include replacement inserts for various cleaning and personal hygiene products. The fibrous article of the present invention can be bonded, laminated or bonded to, or can be used in conjunction with other materials which may or may not be water dispersible. The fibrous article, for example a nonwoven cloth layer, can be attached to a flexible plastic film or liner of a non-water dispersible material, such as polyethylene. For example, such an assembly could be used as a component of a disposable diaper. In addition, the fibrous article may be the result of overblowing fibers onto another substrate to form highly assorted combinations of screened, meltblown, spunbonded film or membrane structures.

Fibrous articles include nonwoven cloths and nets. Nonwoven cloth is defined as cloth made directly from nets without weaving or knitting operations. The Textile Institute defines nonwovens as textile structures made directly from fiber rather than yarn. Typically, these drapes are made from continuous filaments or webs of fibers or batts of fibrous material strengthened by bonding using various techniques, including, but not limited to, adhesive bonding, mechanical stitching by needle insertion, or fluid jet interlocking, thermal bonding and stitch bonding. For example, the multicomponent fiber used in the present invention can be shaped into a cloth by any cloth-forming process. The resulting cloth or web can be converted into a network of microdenier fibers by exerting sufficient force to cause the fibers of

ES 2 403 114 T3 multicomponent are separated or by means of contact of the network with water to remove the sulfopolyester leaving behind the rest of the microdenier fibers.

Thus, the invention employs a process for the preparation of a network of microdenier fibers, comprising:

(A) spinning a water dispersible sulfopolyester having a glass transition temperature (Tg) of at least 57 ° C and one or more non-water dispersible polymers immiscible with the sulfopolyester to give multicomponent fibers, the sulfopolyester comprising:

(i) from about 50 to about 96% by mole of one or more isophthalic acid or terephthalic acid residues, based on the total acid residues;

(ii) from about 4 to about 30% by mole, based on the total acid residues of a sodium sulfoisophthalic acid residue;

(iii) one or more diol residues in which at least 25% by mole, based on the total diol residues, is a poly (ethylene glycol) having the structure

H- (OCH2-CH2) n-OH where n is an integer within the range of 2 to about 500; and (iv) from 0 to about 20% by mole, based on total repeating units, of residues of a branching monomer having 3 or more functional groups in which the functional groups are hydroxyl, carboxyl, or a combination thereof. .

wherein the fibers have a plurality of segments comprising the non-water dispersible polymers wherein the segments are substantially isolated from one another by means of the sulfopolyester intervening between the segments and the fiber contains less than 10% by weight of a pigment or filler, based on the total weight of the fiber;

(B) overlapping and collecting the multicomponent fibers from Step A to form a nonwoven web; and (C) contacting the nonwoven web with water to remove the sulfopolyester thereby forming a network of microdenier fibers.

In another embodiment used in the invention, a process is provided for a network of microdenier fibers comprising:

(A) spinning at least one water-dispersible sulfopolyester and one or more non-water-dispersible polymers immiscible with said sulfopolyester to give rise to multicomponent fibers, said multicomponent fibers having a plurality of domains comprising said non-water-dispersible polymers in those in which said domains are substantially isolated from each other by means of said sulfopolyester intervening between said domains; wherein said fiber has a denier in spun form of less than about 6 denier per filament; wherein said water dispersible sulfopolyester exhibits a melt viscosity of less than about 12,000 poise, measured at 240 ° C at a stress rate of 1 rad / s, and wherein said sulfopolyester comprises less than about 25% in moles of residues of at least one sulfomonoer, based on the total moles of diacid or diol residues;

(B) collecting said multicomponent fibers from Step A) to form a nonwoven web; and (C) contacting said nonwoven web with water to remove said sulfopolyester thereby forming a network of microdenier fibers.

In another embodiment used in the invention, a process is provided for a network of microdenier fibers comprising:

(A) extruding at least one water-dispersible sulfopolyester and one or more non-water-dispersible polymers immiscible with said water-dispersible sulfopolyester to give extruded multicomponent fractions, said extruded multicomponent fractions presenting a plurality of domains comprising said non-water dispersible polymers wherein said domains are substantially isolated from one another by means of said water dispersible sulfopolyester intervening between said domains;

(B) melt extracting said extruded multicomponent fractions at a speed of at least about 2000 m / min to produce multicomponent fibers;

(C) collecting said multicomponent fibers from Step (B) to form a nonwoven web; Y

ES 2 403 114 T3 (D) contacting said nonwoven web with water to remove said sulfopolyester thereby forming a network of microdenier fibers.

Preferably, the process also comprises before Step (C) the step of hydro-entangling the multicomponent fibers of the non-woven network. It is also preferable that the hydro-entangling step results in a loss of less than about 20% by weight of the sulfopolyester present in the multicomponent fibers, more preferably this loss is less than 15% by weight, and most preferably it is less than 10% by weight. As for furthering the goal of reducing sulfopolyester loss during hydro-crosslinking, preferably the water used during the present process has a temperature of less than about 45 ° C, more preferably less than about 35 ° C, and most preferred less than about 30 ° C. It is preferable that the water used during hydroentangling is as close to room temperature as possible, in order to minimize the loss of the sulfopolyester from the multicomponent fibers. Rather, preferably, removal of the sulfopolyester polymer during Step (C) is carried out using water having a temperature of at least about 45 ° C, more preferably at least about 60 ° C, and most preferably of at least about 80 ° C.

After hydroentangling and prior to Step (C), the nonwoven web may undergo a heat setting step which comprises heating the nonwoven web to a temperature of at least about 100 ° C, and more preferably at least about 120 ° C. The heat setting step relaxes the internal tensions of the fibers and helps to generate a dimensionally stable cloth product. It is preferable that when the heat-set material is reheated to the temperature to which it was heated during the heat-setting step, it exhibits a surface area shrinkage of less than about 5% of its original surface area. More preferably, the shrinkage is less than about 2% of the original surface area, and most preferably the shrinkage is less than about 1%.

The sulfopolyester used in the multicomponent fiber can be any of those previously described herein, however, it is preferable that the sulfopolyester has a melt viscosity of less than about 6000 poise measured at 240 ° C at a strain rate. of 1 rad / s and comprising less than about 12 mole%, based on total repeat units, of residues of at least one sulfomonomer. These types of sulfopolyesters have been previously described herein.

Furthermore, a method is described herein which preferably comprises the step of extracting the multicomponent fiber at a fiber speed of at least 2000 m / min, more preferably at least about 3000 m / min, even more preferably of at least about 4000 m / min, and most preferably at least about 5000 m / min.

In another embodiment of the present invention, nonwoven articles comprising non-water dispersible polymer microfibers can be produced. The nonwoven article comprises non-water dispersible polymer microfibers and is produced by means of a process selected from the group consisting of a dry warp process and a wet warp process. Multicomponent fibers and processes for producing non-water dispersible polymer microfibers have been previously described in the specification.

In one embodiment of the invention, at least 1% of the non-water dispersible polymer microfiber is present in the nonwoven article. Other amounts of non-water dispersible polymer microfiber present in the nonwoven article are at least 10%, at least 25% and at least 50%.

In another aspect of the invention, the nonwoven article may further comprise at least one other fiber. The other fiber can be whatever is known in the art depending on the type of nonwoven article to be produced. In one embodiment of the invention, the other fiber can be selected from the group consisting of cellulosic fiber pulp, glass fiber, poly (ester fibers), nylon fibers, poly (olefin fibers), rayon fibers, cellulose ester fibers and mixtures thereof.

The nonwoven article can also comprise at least one additive. Additives include, but are not limited to, starches, fillers, and binders. Other additives are discussed in other sections of this description.

In general, the manufacturing processes to produce these non-woven articles from non-water dispersible microfibers produced from multicomponent fibers can be divided into the following groups: dry warped nets, wet woven nets and combinations of these processes between them or with other nonwoven processes.

Generally, dry-warped nonwovens are manufactured with short fiber processing machinery that is designed to handle fibers in a dry state. These include processes such as carding, streamlining, and other air warp paths. Also included in this category are non-woven articles made from tow-shaped filaments, and cloths made up of short fibers and filaments of stitching or yarns, that is, non-woven materials joined by stitching. Carding is the process of de-entangling, cleaning, and intermixing fibers to prepare a web for further processing into a nonwoven article. The process predominantly aligns the fibers that are held together in a network form by means of mechanical interlacing and

ES 2 403 114 T3 fiber against fiber friction. Generally, cards are configured with one or more main rollers, stationary rollers or stops, one or more combing rollers, or various combinations of these main components. An example of a card is a roller card. The carding action is the combination or processing of the non-water dispersible polymer microfibers between the points of the card, in a series of inter-processing card rollers. Other types of cards include wool, cotton, or random cards. Garnett machines can also be used to align these fibers.

Non-water dispersible polymer microfibers can also be aligned in the dry warp process by means of air warp. These fibers are directed by an air stream over a collector which can be a flat conveyor belt or a drum.

Extrusion formed webs can also be produced from the multicomponent fibers used in the present invention. Examples include spinning and melt blowing. Extrusion technology is used to produce spunbond, meltblown, and porous film nonwoven articles. These nonwovens are manufactured with machinery associated with polymer extrusion methods such as melt spinning, film casting, and extrusion coating. Subsequently, the nonwoven article is contacted with water to remove the water dispersible sulfopolyester, thereby producing an article comprising non-water dispersible polymer microfibers.

In the spunbonding process, the water-dispersible sulfopolyester and the non-water-dispersible polymer are directly transformed into a cloth by means of extrusion of the multicomponent filaments, orienting them in the form of bundles or clusters, stratifying them on a sieve. of transport and causing the framework of the same. The lattice can be carried out by means of thermal fusion, mechanical entanglement, hydro-entanglement, chemical binders, or combinations of these processes.

Melt blown cloths are also prepared directly from the water dispersible sulfopolyester and the non-water dispersible polymer. The polymers are melted and extruded. As soon as the melt passes through the extrusion hole, it is blown with high temperature air. The air stream attenuates and solidifies the molten polymers. Subsequently, the multicomponent fibers can be separated from the air stream in the form of a net and can be compressed between hot rollers.

Combined melt bonding and spun bonding processes can also be used to produce nonwovens.

Wet warp processes involve the use of papermaking technology to generate nonwoven articles. These nonwovens are manufactured with machinery associated with the formation of pulp fibers, such as hammer mills and paper formation machinery. For example, pumping a suspension over continuous sieves that are designed to handle short fibers in a fluid.

In one embodiment of the wet warp process, non-water dispersible polymer microfibers are suspended in water, transported to a forming unit where the water is drained through a forming screen, and the fibers are deposited onto the sieve wire.

In another embodiment of the wet warp process, the microfibers of the non-water dispersible polymer are dewatered on a screen or wire mesh that is rotated at the beginning of the hydraulic molds with respect to the dewatering modules (suction boxes, metallized papers and curvatures) at high speeds of up to 1500 meters per minute. Subsequently, the sheet is deposited on this wire and dehydration proceeds until obtaining a solids content of approximately 20-30%. The film can then be compressed and dried.

In another embodiment of the wet warp process, a process is provided comprising:

a) optionally, washing non-water dispersible polymer microfibers with water;

b) adding water to the non-water dispersible polymer microfibers, to produce a non-water dispersible polymer microfiber suspension;

c) optionally adding other fibers and / or additives to the non-water dispersible polymer microfibers or suspension; Y

d) transferring the suspension containing non-water dispersible polymer microfibers to a zone of wet warped nonwoven to produce a nonwoven article.

In Step a), the number of washes depends on the particular use chosen for the non-water dispersible polymer microfibers. In Step b), sufficient water is added to the microfibers to allow them to be driven into the area of ​​the wet-warped nonwoven.

The wet warp nonwoven zone comprises any equipment known in the art for producing wet warp nonwovens. In one embodiment of the invention, the zone of nonwoven material

Wet-warped ES 2 403 114 T3 comprises at least one screen or metal mesh for removing water from the non-water dispersible polymer microfiber suspension.

In another embodiment of the invention, the non-water dispersible polymer microfiber suspension is mixed prior to being transferred to the wet warped nonwoven zone.

Wet bonding processes can also be used to produce nonwovens. These can be divided into chemical and physical processes. Chemical bonding refers to the use of water-based or solvent-based polymers to bond fibers and / or fibrous networks. These binders can be applied by saturation, impregnation, spraying, printing, or foam application. Physical bonding processes include thermal processes such as calendering and hot air bonding, and mechanical processes such as needle insertion and hydroentangling. The processes of inserting needles or puncture of needles cause the interweaving of the fibers by means of the physical movement of some fibers from a position close to the horizontal to a position close to the vertical. Needle puncture can be carried out by means of punching device. Generally, the punching device contains a web feed mechanism, a needle beam comprising a needle panel housing the needles, a spacer plate, a bed plate, and a cloth pick-up mechanism.

Seam bonding is a mechanical bonding method that uses knitting elements, with or without yarn, to cause weaving of fiber networks. Examples of joining by seam joining machines include, but are not limited to, Maliwatt, Arachne, Malivlies, and Arabeva.

The nonwoven article can be held together by means of 1) mechanical fiber cohesion and weaving into a net or mat; 2) various fiber fusion techniques, including the use of binder fibers, that utilize the thermoplastic properties of certain polymers and polymer blends; 3) using a binding resin such as starch, casein, a cellulose derivative or a synthetic resin, such as acrylic or urethane latex; 4) adhesive binders in powder form; or 5) their combinations. Often the fibers are deposited randomly, although orientation in one direction is possible, followed by bonding using one of the methods described above.

The fibrous articles of the invention may furthermore also comprise one or more layers of water dispersible fibers, multicomponent fibers or microdenier fibers. The fiber layers can be one or more nonwoven layers, a loosely bonded layer of overlapping fibers, or a combination thereof. In addition, fibrous articles can include personal hygiene products such as, but not limited to, infant hygiene products, such as baby diapers; toilet training pants for children; adult hygiene products, such as adult diapers and adult incontinence pads; feminine hygiene products, such as sanitary napkins, panty liners and tampons; wipes; fiber-containing cleaning products; medical and surgical hygiene products, such as medical wipes, tissues, gauze, exam table covers, surgical masks, gowns, bandages and wound dressings; cloths; elastomeric yarns, wipes, tapes, other protective barriers and packaging material. Fibrous articles can be used to absorb liquids or can be pre-wetted with various liquid compositions and can be used to deliver these compositions to a surface. Non-limiting examples of liquid compositions include detergents; wetting agents; cleaning agents; products for skin hygiene, such as cosmetic products, ointments, medicines, emollients and fragrances. Fibrous articles can also include various powders and particulate materials to enhance absorbency or as delivery vehicles. Examples of powders and particulate materials include, but are not limited to, talc, starches, various water-swellable, water-dispersible or water-absorbent polymers, such as super-absorbent polymers, sulfopolyesters and polyvinyl alcohols, silica , pigments and microcapsules. Additives may also be present, but are not required, as necessary for specific applications. Examples of additives include, but are not limited to, oxidative stabilizers, UV absorbers, colorants, pigments, opacifiers (delusters), optical brighteners, fillers, nucleating agents, plasticizers, viscosity modifiers, surface modifiers, anti-microbials, disinfectants, cold flow inhibitors, branching agents and catalysts.

In addition to being water dispersible, the fibrous articles described above may be flushable. The term "flushable" as used herein means capable of being flushed out of a conventional bathroom, and disposed of through the residential or municipal sanitation or sewage treatment system, without causing a clogged or blocked toilet or sewage system.

The fibrous article further comprises a water dispersible film comprising a second water dispersible polymer. The second water dispersible polymer may be the same or different from the previously described water dispersible polymers used in the fibers and fibrous articles of the present invention. In one embodiment, for example, the second water-dispersible polymer may be an additional sulfopolyester which, in turn, comprises:

(A) from about 50 to about 96% by mole of one or more isophthalic acid or terephthalic acid residues, based on the total acid residues;

ES 2 403 114 T3 (B) from about 4 to about 30% by mole, based on total acid residues, of a sodium isophthalic acid residue;

(C) one or more diol residues in which at least 15% by mole, based on the total diol residues, is a poly (ethylene glycol) having a structure

H- (OCH2-CH2) n-OH where n is an integer within the range of 2 to about 500;

(D) from 0 to about 20% by mole, based on total repeat units, of residues of a branching monomer having 3 or more functional groups in which the functional groups are hydroxyl, carboxyl, or a combination thereof. The additional sulfopolyester can be mixed with one or more complementary polymers, as described above, in order to modify the properties of the resulting fibrous article. The complementary polymer may or may not be water dispersible depending on the application. The complementary polymer can be miscible or immiscible with the additional sulfopolyester.

The additional sulfopolyester may contain other concentrations of isophthalic acid residues, for example, from about 60 to about 95% by mole and from about 75 to about 95% by mole. Additional examples of isophthalic acid residue concentration ranges are from about 70 to about 85% by mole, from about 85 to about 95% by mole, and from about 90 to about 95% by mole. The additional sulfopolyester can also comprise from about 25 to about 95 mole% of the diethylene glycol residues. Additional examples of diethylene glycol residue concentration ranges include from about 50 to about 95% by mole, from about 70 to about 95% by mole, and from about 75 to about 95% by mole. The additional sulfopolyester can also include ethylene glycol and / or 1,4-cyclohexanedimethanol residues. CHDM residue concentration ranges are from about 10 to about 75% by mole, from about 25 to about 65% by mole, and from about 40 to about 60% by mole. Typical concentration ranges for ethylene glycol residues are from about 10 to about 75% by mole, from about 25 to about 65% by mole, and from about 40 to about 60% by mole. In another embodiment, the additional sulfopolyester comprises from about 75 to about 96 mole% isophthalic acid residues and from about 25 to about 95 mole% diethylene glycol residues.

The sulfopolyester film component of the fiber article can be produced in the form of a monolayer or multilayer film. The multilayer film can be produced by conventional molding techniques. Multilayer films can be produced by means of conventional laminating methods or the like. The film can be of any appropriate thickness, but typically the total thickness will be between about 2 and about 50 thousandths of an inch (0.127 cm).

The film-containing fibrous articles can include one or more layers of water dispersible fibers as described above. The fiber layers may be one or more nonwoven layers, a loosely bonded layer of overlapping fibers, or a combination thereof. In addition, fibrous film-containing articles may include personal hygiene and sanitary products such as those described above.

As described above, fibrous articles can also include various powders and particles to enhance absorbency or as delivery vehicles. Thus, in one embodiment, our fibrous article comprises a powder comprising a third water dispersible polymer which may be the same or different from the water dispersible polymer components previously described herein. Other examples of powders and particulate materials include, but are not limited to, talc, starches, various water-swellable or water-dispersible polymers, and water absorbents, such as polyacrylonitriles, sulfopolyesters and polyvinyl alcohols, silica, pigments and microcapsules.

The inventors' novel and fibrous articles have many possible uses in addition to the applications described above. A new application involves melt blowing a nonwoven film or cloth onto smooth, curved or shaped surfaces to provide a protective layer. Such a layer could provide surface protection to durable equipment during transportation. At the point of destination, before putting the equipment into service, the outer layers of sulfopolyester could be washed. Another embodiment of this generally applicable concept could involve personal protective articles to provide temporary barrier layers for some limited use or reusable garments or covers. For the military application case, it is possible to spray activated carbon and chemical absorbers on the attenuation filament pattern just before the collector, in order to allow the fixation of the melt blown matrix to these bodies on the exposed surface. Chemical absorbers can even be modified in the forward operations area as the hazard arises by melt blowing onto another layer.

An inherent advantage of sulfopolyesters is the simple ability to remove or recover polymer from aqueous dispersions through flocculation or precipitation through the addition of ionic moieties (ie salts). Other methods can also be used, such as pH adjustment, addition of substances that are not

ES 2 403 114 T3 solvents, freezing and the like. Thus, potentially fibrous articles, such as protective clothing for external use, can be safely handled after successful use of the protective barrier and even if the polymer becomes hazardous waste, with much smaller volumes for their disposal using accepted protocols, such as incineration.

Undissolved or dried sulfopolyesters are known to form strong adhesive bonds with a wide range of substrates including, but not limited to, shredded fiber pulp, cotton, acrylic materials, rayon, lyocell, PLA (polylactides), cellulose acetate, Cellulose propionate and acetate, poly (ethylene terephthalate), poly (butylene terephthalate), poly (trimethylene terephthalate), poly (cyclohexylene terephthalate), copolyesters, polyamides (nylons), stainless steel, aluminum, treated polyolefins, PAN (polyacrylonitriles) and polycarbonates. Thus, the inventors' nonwoven cloths can be used as laminating adhesives or binders that can be bonded by known techniques, such as thermal, radio frequency (RF), microwave and ultrasound methods. The adaptation of sulfopolyesters to allow RF activation is described in a number of recent patents. Thus, the new nonwoven cloths can exhibit dual or uniform multifunctionality in addition to adhesive properties. For example, a disposable baby diaper could be obtained in which the nonwoven material of the present invention serves on the one hand as a water-responsive adhesive as well as a fluid management component of the final assembly.

A process for water dispersible fibers is also described herein comprising:

(A) heating a water dispersible polymer composition to a temperature above its dew point, wherein the polymer composition comprises:

(i) residues of one or more dicarboxylic acids;

(ii) from about 4 to about 40 mole%, based on total repeat units, of residues of at least one sulfomonomer having 2 functional groups and one or more metal sulfonate groups attached to an aromatic or cycloaliphatic ring in where the functional groups are hydroxyl, carboxyl, or a combination thereof; and (iii) one or more diol residues in which at least 20% by mole, based on the total diol residues, is a poly (ethylene glycol) having the structure

H- (OCH2-CH2) n-OH where n is an integer within the range of 2 to about 500; (iv) from 0 to about 25% by mole, based on total repeat units, of residues of a branching monomer having 3 or more functional groups in which the functional groups are hydroxyl, carboxyl, or a combination thereof; wherein the polymer composition contains less than 10% by weight of a pigment or filler, based on the total weight of the polymer composition; and (II) melt spinning filaments. As discussed above, the water dispersible polymer can optionally be mixed with the sulfopolyester. Also, optionally, a non-water dispersible polymer can be blended with the sulfopolyester to form a blend that is immiscible. The term dew point, as used herein, means the temperature at which the viscosity of the polymer composition allows extrusion or other forms of processing through the extrusion die or die. The dicarboxylic acid residue can comprise from about 60 to about 100 mole% of the acid residues depending on the type and concentration of the sulfomonomer. Other examples of dicarboxylic acid residue concentration ranges are from about 60 mole% to about 95 mole% and from about 70 mole% to about 95 mole%. Preferred dicarboxylic acid residues are isophthalic, terephthalic and 1,4-cyclohexane-dicarboxylic acids or if diesters are used, dimethyl terephthalate, dimethyl isophthalate and dimethyl 1,4-cyclohexanedicarboxylate, the isophthalic and terephthalic acid residues being especially preferred.

The sulfomonomer can be a dicarboxylic acid or one of its esters that contains a sulfonate group, a diol that contains a sulfonate group, or a hydroxy acid that contains a sulfonate group. Additional examples of concentration ranges for sulfomonomer residues are from about 4 to about 25% by mole, from about 4 to about 20% by mole, from about 4 to about 15% by mole, and from about 4 to about 10%. in moles, based on total repeating units. The cation of the sulfonate salt can be a metal ion such as Li⁺, Na⁺, K⁺, Mg⁺⁺, Ca⁺⁺, Neither⁺⁺, Faith⁺⁺ and similar. Alternatively, the cation of the sulfonate salt can be non-metallic such as a nitrogenous base as previously described. Examples of sulfomonomer residues that can be used in the process of the present invention are the metal sulfonate salt of sulfphthalic acid, sulfoterephthalic acid, sulfoisophthalic acid, or a combination thereof. Another example of the sulfomonomer that can be used is 5-sodium sulfoisophthalic acid or its esters. If the sulfomonomer residue is 5-sodium sulfoisophthalic acid, typical sulfomonomer concentration ranges are from about 4 to about 35% by mole, from about 8 to about 30% by mole, and from about 10 to about 25% by mole, based in total acid residues.

ES 2 403 114 T3

The sulfopolyester includes one or more diol residues which may include aliphatic, cycloaliphatic, or aralkyl glycols. Cycloaliphatic diols, for example 1,3- and 1,4-cyclohexanedimethanol, can be present in the form of their pure cis or trans isomers or as a mixture of cis and trans isomers. Non-limiting examples of low molecular weight polyethylene glycols, that is, in which n is 2 to 6, are diethylene glycol, triethylene glycol, and tetraethylene glycol. Of these low molecular weight glycols, diethylene and triethylene glycol are the most preferred. Optionally, the sulfopolyester can include a branching monomer. Examples of branching monomers are those described above. Other examples of branching monomer concentration ranges are 0 to about 20 mole% and 0 to about 10 mole%. The sulfopolyester from our new process has a Tg of at least 25 ° C. Other examples of glass transition temperatures exhibited by sulfopolyester are at least 30 ° C, at least 35 ° C, at least 40 ° C, at least 50 ° C, at least 60 ° C, at least 65 ° C, at least 80 ° C and at least 90 ° C. Although other Tg values ​​are possible, the glass transition temperatures of the dry sulfopolyesters used in the invention are about 30 ° C, about 48 ° C, about 55 ° C, about 65 ° C, about 70 ° C, about 75 ° C. ° C, about 85 ° C and about 90 ° C.

The water dispersible fibers are prepared by means of a melt blown process. The polymer is melted in an extrusion device and passed through a die. The extruded fraction leaving the die is rapidly quenched to ultra-fine diameters by hot air at high speed. The orientation, cooling rate, glass transition temperature (Tg) and crystallization rate of the fiber are important because they affect the viscosity and processing properties of the polymer during attenuation. The filament is collected on a renewable surface, such as a moving belt, cylindrical drum, rotating mandrel, and the like. Pellet pre-drying (if necessary), extruder zone temperature, melting temperature, screw design, production rate, air temperature, air flow (speed) , the air gap of the nozzle and drop, the orifice size of the nose tip, the temperature of the nozzle, the distance from the nozzle to the manifold (DCP), the inactivation environment, collector speed and post-treatments are all factors that influence product characteristics such as filament diameters, basis weight, web thickness, pore size, softness, and shrinkage. A high air speed can also be used to move the filaments quite randomly so that the result is a broad interlacing. If a moving tape is passed under the nozzle, a nonwoven cloth can be produced by the combination of overlap deposition, mechanical cohesion and thermal bonding of the filaments. Overblowing carried out on another substrate, such as a spunbonded or liner layer, is also possible. If the filaments are captured by a rotating mandrel, a cylindrical product is formed. A water dispersible fiber reservoir can also be prepared by the spunbond process.

Furthermore, a process for a water dispersible nonwoven cloth is described herein comprising:

(A) heating a water dispersible polymer composition to a temperature above its pour point, wherein the polymer composition comprises (i) residues of one or more dicarboxylic acids;

(ii) from about 4 to about 40 mole%, based on total repeat units, of residues of at least one sulfomonomer having 2 functional groups and one or more metal sulfonate groups attached to an aromatic or cycloaliphatic ring in where the functional groups are hydroxyl, carboxyl, or a combination thereof;

(iii) one or more diol residues in which at least 20% by mole, based on the total diol residues, is a poly (ethylene glycol) having the structure

H- (OCH2-CH2) n-OH where n is an integer within the range of 2 to about 500;

(iv) from 0 to about 25% by mole, based on total repeat units, of residues of a branching monomer having 3 or more functional groups in which the functional groups are hydroxyl, carboxyl, or a combination thereof; wherein the sulfopolyester has a glass transition temperature (Tg) of at least 25 ° C; wherein the polymer composition contains less than 10% by weight of a pigment or filler, based on the total weight of the polymer composition;

(B) melt spinning the filaments; and (C) overlapping a collect the filaments of Step (B) to form a nonwoven cloth. As discussed above, the water dispersible polymer can optionally be mixed with the sulfopolyester. In addition, a non-water dispersible polymer can optionally be blended with the sulfopolyester to form a blend that is immiscible. The dicarboxylic acid, the sulfomonomer, and the branching monomer residues are as described above. The sulfopolyester has a Tg of at least 25 ° C. Other examples

ES 2 403 114 T3 glass transition temperatures exhibited by sulfopolyester are at least 30 ° C, at least 35 ° C, at least 40 ° C, at least 50 ° C, at least 60 ° C, at least 65 ° C , at least 80 ° C and at least 90 ° C. Although other Tg values ​​are possible, typical glass transition temperatures of the sulfopolyesters of the invention are about 30 ° C, about 48 ° C, about 55 ° C, about 65 ° C, about 70 ° C, about 75 ° C. C, about 85 ° C and about 90 ° C. The invention is further illustrated by means of the following examples.

Examples

All pellets were pre-dried under vacuum at room temperature for at least 12 hours. The dispersion times shown in Table 3 are for either complete dispersion or dissolution of the nonwoven samples. The abbreviation CE used in Tables 2 and 3 means comparative example.

Example 1 (Reference Example)

A sulfopolyester containing 76 mol% isophthalic acid, 24 mol% sodium sulfoisophthalic acid, 76 mol% diethylene glycol and 24 mol% 1,4-cyclohexanedimethanol with an Ih.V of 0, was melt blown. 29 and Tg of 48 ° C, through a 6-inch (15.24 cm) nozzle (30 holes / inch (2.54 cm) in the nose piece) onto a cylindrical manifold using the conditions given shown in Table 1. No intermediate film-forming paper was required. A flexible, manageable and soft net was obtained that did not cause blockage during the rolling operation of the roll. Table 2 provides the physical properties. A small piece (1 x 3) (2.54 cm x 7.62 cm) of nonwoven cloth was easily dispersed in water both at room temperature (RT) and at a temperature of 50 ° C with light agitation as shown the data in Table 3.

Table 1 - Melt Blowing Conditions

<td>Operation Condition</td><td>Typical Value</td>

<td colspan="2">Nozzle Configuration</td>

<td>Nozzle tip hole diameter</td><td>0.0185 inch (0.04699 cm)</td>

<td>Number of holes</td><td> 120</td>

<td>Air space</td><td>0.060 inch (0.1524 cm)</td>

<td>Drop</td><td>0.060 inch (0.1524 cm)</td>

<td colspan="2">Extrusion Device Barrel Temperatures (° F)</td>

<td>Zone 1</td><td>350 (176.7 ° C)</td>

<td>Zone 2</td><td>510 (265.5 ° C)</td>

<td>Zone 3</td><td>510 (265.5 ° C)</td>

<td colspan="2">Nozzle Temperatures (° F)</td>

<td>Zone 4</td><td>510 (265.5 ° C)</td>

<td>Zone 5</td><td>510 (265.5 ° C)</td>

<td>Zone 6</td><td>510 (265.5 ° C)</td>

<td>Zone 7</td><td>510 (265.5 ° C)</td>

<td>Zone 8</td><td>510 (265.5 ° C)</td>

<td colspan="2">Air temperatures (° F)</td>

<td>Oven outlet 1</td><td>350 (176.7 ° C)</td>

<td>Oven outlet 2</td><td>700 (371.1 ° C)</td>

<td>Oven outlet 3</td><td>700 (371.1 ° C)</td>

<td>Nozzle</td><td>530-546 (276.7-285.5 ° C)</td>

<td colspan="2">Extrusion Conditions</td>

<td>Air pressure</td><td>3.0 psi (20.68 kPa)</td>

<td>Molten Mass Pressure After Pumping</td><td>99-113 psi (682.6-779.1 kPa)</td>

ES 2 403 114 T3

<td colspan="2">Funding Conditions</td>

<td>Performance</td><td>0.3 g / hole / min 0.5 g / hole / min</td>

<td>Base Weight</td><td>36 g / m²</td>

<td>Collector Speed</td><td>20 ft / min (609.6 cm / min)</td>

<td>Collector Distance</td><td>12 inches (30.5 cm)</td>

Table 2 - Physical Properties of Non-Woven Materials

<td rowspan="2">Example</td><td colspan="3">Filament Diameter (pm)</td><td rowspan="2">IhV (before after)</td><td rowspan="2">Tg / Tm (° C) (sufopolymer / PP)</td>

<td>Minimum</td><td>Maximum</td><td>Half</td>

<td> 1</td><td> 5</td><td> 18</td><td> 8,7</td><td> 0,29/0,26</td><td>39 / not applicable</td>

<td> 2</td><td> 3</td><td> 11</td><td> 7,7</td><td> 0,40/0,34</td><td>36 / not applicable</td>

<td>CE 1</td><td> 2</td><td> 20</td><td> 8</td><td>Not measured</td><td> 36/163</td>

<td>CE 2</td><td> 4</td><td> 10</td><td> 7</td><td>Not measured</td><td> 36/164</td>

<td>CE 3</td><td> 4</td><td> 11</td><td> 6</td><td>Not measured</td><td> 35/161</td>

Table 3 - Dispersion Ability of Non-Woven Materials

<td>Example</td><td>Water temperature (° C)</td><td>Initial Disintegration (minutes)</td><td>Significant Disintegration (minutes)</td><td>Complete Dispersion (minutes)</td>

<td rowspan="2"> 1</td><td> 23</td><td> &lt; 0,25</td><td> 1</td><td> 2</td>

<td> 50</td><td> &lt; 0,17</td><td> 0,5</td><td> 1</td>

<td rowspan="3"> 2</td><td> 23</td><td> 8</td><td> 14</td><td> 19</td>

<td> 50</td><td> &lt; 0,5</td><td> 5</td><td> 8</td>

<td> 80</td><td> &lt; 0,5</td><td> 2</td><td> 5</td>

<td rowspan="2">CE 1</td><td> 23</td><td> 0,5</td><td> &gt; 15</td><td>No PP dispersion</td>

<td> 50</td><td> 0,5</td><td> &gt; 15</td><td>No PP dispersion</td>

<td rowspan="2">CE 2</td><td> 23</td><td> 0,5</td><td> &gt; 15</td><td>No PP dispersion</td>

<td> 50</td><td> 0,5</td><td> &gt; 15</td><td>No PP dispersion</td>

<td rowspan="2">CE 3</td><td> 23</td><td> &lt; 0,5</td><td> 6</td><td>No PP dispersion</td>

<td> 50</td><td> &lt; 0,5</td><td> 4</td><td>No PP dispersion</td>

Example 2 (Reference Example)

A sulfopolyester containing 89 mol% isophthalic acid, 11 mol% sodium sulfoisophthalic acid, 72 mol% diethylene glycol and 28 mol% ethylene glycol with an Ih.V of 0.4 and Tg of 35 ° C, through a 6-inch (15.24 cm) nozzle using conditions similar to those in Table 1. A flexible, manageable and soft web was obtained that did not cause blockage during the roll winding operation. Table 2 provides the physical properties. A small piece (1 x 2) (2.54 cm x 5.08 cm) of nonwoven cloth was easily and completely dispersed in water at 50 ° C and 80 ° C; At RT (23 ° C), the cloth required a longer period of time for complete dispersion as shown by the data in Table 3.

It was found that the compositions of Examples 1 and 2 can be overblown onto other nonwoven substrates. It is also possible to condense and roll shaped and shaped shapes that are used in place of conventional collectors for networks. In this way, it is possible to obtain circular discontinuous fiber or plug shapes of the nets.

ES 2 403 114 T3

Comparative Examples 1-3

Pellets of a sulfopolyester containing 89 mol% isophthalic acid, 11 mol% sodium isophthalic acid, 72 mol% diethylene glycol and 28 mol% ethylene glycol were combined with an Ih.V of 0.4 and Tg of 35 ° C with polypropylene pellets (Basell PF 008) in two-component proportions (in% by weight) of:

PP: 25 sulfopolyester (Example 3)

PP: 50 sulfopolyester (Example 4)

PP: 75 sulfopolyester (Example 5)

The PP had an MFR (melt flow rate) of 800. The melt blowing operation was carried out in a line equipped with a 24-inch wide nozzle to produce manageable, soft, flexible and non-flexible nets. caused blocking with the physical properties given in Table 2. Small pieces (1 x 4) (2.54 cm x 10.16 cm) of nonwoven cloth as presented in Table 3 disintegrated easily. However, none of the fibers were completely dispersible due to the insoluble polypropylene component.

Example 3 (Reference Example)

A circular piece (4 (10.16 cm) diameter) of nonwoven material produced in Example 2 was used as an adhesive layer between two sheets of cotton cloth. A Hannifin melt press was used to melt the two sheets of cotton together by applying a pressure of 35 psig (241.3 kPa) at 200 ° C for 3 seconds. The resulting assembly exhibited exceptionally strong bond strength. Cotton substrate shredded prior to bond or adhesive failure. Similar results were also obtained with other cellulosic materials and with PET polyester substrates. Strong bonds were also produced by ultrasonic bonding techniques.

Comparative Example 4

A PP (Exxon 3356G) was melt blown with 1200 MFR using a 24 (60.96 cm) nozzle to give a flexible non-woven cloth that did not cause blocking and easily unrolled from the roll. Small pieces (1 x 4) (2.54 x 10.16 cm) did not show any response (i.e. no disintegration or loss in base weight) to water when immersed in water at Rt or 50 ° C for 15 minutes.

Example 4 (Reference Example)

Sulfopolyester unicomponent fibers containing 82 mol% isophthalic acid, 18 mol% sodium sulfoisophthalic acid, 54 mol% diethylene glycol and 46 mol% 1,4-cyclohexanedimethanol with a Tg of 55 ° C were melt spun. , at melting temperatures of 245 ° C (473 ° F) on a laboratory short fiber spinning line. The denier in spun form was approximately 8 d / f. Some blockage was found in the collection tubes, but the filament-10 strand dissolved easily in 10-19 seconds in demineralized, non-stirred water at 82 ° C and a pH between 5 and 6.

Example 5 (Reference Example)

Unicomponent fibers obtained from a mixture (75:25) of a sulfopolyester containing 82 mol% isophthalic acid, 18 mol% sodium sulfoisophthalic acid, 54 mol% diethylene glycol, and 46 mol% diethylene glycol were melt spun. moles of 1,4-cyclohexanedimethanol (Tg 55 ° C) and a sulfopolyester containing 91 mole% isophthalic acid, 9 mole% sodium isophthalic acid, 25 mole% diethylene glycol and 75 mole% isophthalic acid.

1,4-cyclohexanedimethanol (Tg of 65 ° C), respectively, on a laboratory short fiber spinning line. The mixture had a Tg of 57 ° C, calculated by taking a weighted average of the Tg values ​​of the component sulfopolyesters. The 10-filament strands did not show any blockage in the collection tubes, but dissolved easily in 20-43 seconds in demineralized, non-stirred water at 82 ° C and a pH between 5 and 6.

Example 6 (Reference Example)

The blend described in Example 5 was subjected to co-spinning with PET to produce bicomponent fibers from islands in the sea. A configuration was obtained in which the sulfopolyester sea is 20% by weight of the fiber containing 80% by weight of PET islands. The stretch of the spun yarn was 190% immediately after spinning. No blockage was found as the yarn was satisfactorily unwound from the bobbins and processed one week after spinning. In a subsequent operation, the sea was dissolved by passing the yarn through a soft water bath at 88 ° C leaving only fine PET filaments.

Example 7 (Reference Example)

This example illustrates the possible application of the microdenier and multicomponent fibers of the present invention to the preparation of specialty papers. The mixture described in Example 5 was subjected to co-spinning with PET to

ES 2 403 114 T3 produce bicomponent fibers from islands in the sea. The fiber contains about 35% by weight of sulfopolyester sea component and about 65% by weight of PET islands. The non-crimped fiber is cut to lengths of 1/8 inch (0.3175 cm). In simulated papermaking, these short bicomponent fibers are added to the refining operation. The sulfopolyester sea in the stirred aqueous suspension is removed, thereby releasing the microdenier PET fibers into the mixture. At comparable weights, microdenier (island) PET fibers are more effective in increasing the tensile strength of paper than the addition of coarse PET fibers.

Comparative Example 8

Bicomponent fibers having 108 islands in the sea structure were prepared in a spunbond line using a 24 (60.96 cm) wide bicomponent spinneret from Hills Inc., Melbourne, FL, having a total of 2222 nozzle holes in nozzle plate. Two extrusion devices were connected to melt pumps which, in turn, were connected to the inlets for both components of the fiber spinning die. The primary extruder (A) was connected to the Eastman F61HC PET polyester flow measuring inlet to form the island domains in the cross-sectional structure of the island-type fiber in the sea. The extrusion zones were set to melt the PET entering the die at a temperature of 285 ° C. Secondary extruder (B) processed Eastman AQ 55S sulfopolyester polymer from Eastman Chemical Company, Kingsport, TN which had an inherent viscosity of approximately 0.35 and a melt viscosity of approximately 15,000 poise, measured at 240 ° C and a sheer rate of 1 rad / s and 9,700 poise measured at 240 ° C and a sheer rate of 100 rad / s on a Rheometric Dynamic Analyzer RDAII rheometer (Rheometrics Inc. Piscataway, New Jersey). Before carrying out the melt viscosity measurement, the sample was dried for two days in a vacuum oven at 60 ° C. Viscosity testing was carried out using a 25mm diameter parallel plate geometry at a 1mm spatial setting. A dynamic frequency sweep was operated in a strain rate range of 1 to 400 rad / s and 10% strain amplitude. Subsequently, the viscosity was measured at 240 ° C and a stress rate of 1 rad / s. The present procedure was followed to determine the viscosity of the sulfopolyester materials used in subsequent examples. The secondary extruder was set to melt and feed the AQ 55S polymer at a melt temperature of 255 ° C at the die die. The two polymers were shaped to give extruded bicomponent fractions by means of extrusion at a production rate of 0.6 g / hole / min. The volume ratio of PET to AQ 55S in the extruded bicomponent fractions was adjusted to generate 60/40 and 70/30 ratios.

A suction device was used to melt the extruded bicomponent fractions to produce the bicomponent fibers. The flow of air through the suction chamber pulled the resulting fibers downward. The amount of air flowing down through the suction device assembly was controlled by the pressure of the air entering the suction device. In the present example, the maximum air pressure used in the suction device to melt the extruded bicomponent fractions was 25 psi. Above this value, the air flow through the suction device caused the extruded fractions to break apart during this melt extraction spinning process as the melt extraction rate imposed on the bicomponent fractions extruded was greater than the inherent ductility of the extruded bicomponent fractions. The bicomponent fibers were warped to produce a nonwoven web having a cloth weight of 95 grams per square meter (gsm). The evaluation of the bicomponent fibers of the present nonwoven network by means of optical microscopy showed that PET was present in the form of islands in the center of the fiber structure, but that the islands of PET that were around the The periphery of the bicomponent fiber practically coalesced together to form a nearly continuous ring of PET polymer around the circumference of the fibers, which is undesirable. Microscopy found that the diameter of the bicomponent fibers in the nonwoven web was generally 15-19 microns, corresponding to a mean spun denier value of the fiber of approximately 2.5 denier per filament ( dpf). This represents a melt drawn fiber velocity of approximately 2,160 meters per minute. The denier value in spun form is defined as the fiber denier (weight in grams of 9000 meter fiber length) obtained through the melt extrusion and melt extraction steps. The variation in diameter of the bicomponent fiber indicated lack of uniformity in the spinning-extraction of the fibers.

The non-woven net samples were conditioned in a forced air oven for five minutes at 120 ° C. The heat-treated web exhibited significant shrinkage, with the nonwoven web area decreasing by only about 12% of the initial web area prior to heating. Without wishing to be bound by any theory, due to the high molecular weight and melt viscosity of the AQ 55S sulfopolyester used in the fiber, it was not possible to melt extract the extruded bicomponent fractions to the extent required to cause crystallization. induced by stress of the PET segments of the fibers. Above all, the AQ 55S sulfopolyester exhibiting this specific inherent viscosity and melt viscosity was not acceptable as it was not possible to uniformly melt the extruded bicomponent fractions with the desired fine denier value.

ES 2 403 114 T3

Example 8 (Reference Example)

A sulfopolyester polymer was produced with the same chemical composition as the commercial Eastman AQ55S polymer, however, the molecular weight was controlled to a lower value characterized by an inherent viscosity of approximately 0.25. The melt viscosity of the present polymer was 3300 poise measured at 240 ° C and a shear rate of 1 rad / s.

Example 9 (Reference Example)

Extruded bicomponent fractions having a 16-piece segmented pie structure were prepared using a bicomponent spinneret die from Hills Inc., Melbourne, FL, which had a total of 222 die holes in a 24 die plate. inches (60.96 cm) wide on a spunbond kit. Two extrusion devices were used to melt and feed the two polymers to this die die. The primary extruder (A) was connected to the inlet, where the Eastman F61HC PET polyester is melted to form the domains or segment cuts of the segmented pie cross-sectional structure. The extrusion zones were adjusted to melt the PET entering the die die at a temperature of 285 ° C. The secondary extruder (B) melted and fed the polyester polymer of Example 8. The secondary extruder was set to extrude the sulfopolyester polymer at a melt temperature of 255 ° C into the die die. Except for the spinneret used and the melt viscosity of the sulfopolyester polymer, the procedure employed in the present example was the same as in Comparative Example 8. The melt yield per orifice was 0.6 g / min. . The volume ratio of PET to sulfopolyester in the extruded bicomponent fractions was adjusted to 70/30, representing a weight ratio of about 70/30.

The extruded bicomponent fractions were melt extracted using the same aspiration device used in Comparative Example 8 to produce the bicomponent fibers. Initially, the air inlet to the suction device was set to 25 psi (172.4 kPa) and the fibers had a denier value in spun form of approximately 2.0, with the bicomponent fibers showing a uniform diameter profile of approximately 14-15 microns. The air entering the suction device was increased to a maximum available pressure of 45 psi (310.3 kPa) without rupturing of the melt extruded fractions during melt extraction. Using air at 45 psi (310.3 kPa), the extruded bicomponent fractions were melt extracted to obtain a denier value of the fiber in spun form of approximately 1.2, exhibiting the fibers of bicomponent with a diameter of 11-12 microns when viewed under a microscope. The speed during the melt extraction process was calculated to be about 4500 m / min. Without wishing to be bound by theory, at melt extraction rates approaching this speed, it is believed that stress-induced crystallization of PET during the melt extraction process begins to appear. As discussed above, it is desirable to form some oriented crystallinity in the PET fiber segments during the melt fiber extraction process so that the nonwoven web is more dimensionally stable during further processing.

The biocomponent fibers were warped using a suction device air pressure of 45 psi (310.3 kPa) to produce a nonwoven web weighing 140 grams per square meter (gsm). Shrinkage of the nonwoven web was measured by conditioning the material in a forced air oven for five minutes at 120 ° C. This example represents a significant reduction in shrinkage compared to the fibers and cloth of Comparative Example 8.

This non-woven net having a cloth weight of 140 gsm was immersed for five minutes in a deionized water bath at various temperatures. The immersed nonwoven net was dried, and the percentage weight loss due to immersion in deionized water at various temperatures was measured as shown in Table 4.

Table 4

<td>Immersion Temperature</td><td>25 ° C</td><td>33 ° C</td><td>40 ° C</td><td>72 ° C</td>

<td>Nonwoven Net Weight Loss (%)</td><td> 3,3</td><td> 21,7</td><td> 31,4</td><td> 31,7</td>

The sulfopolyester dissipated very easily in deionized water at a temperature of about 25 ° C. The removal of the sulfopolyester from the bicomponent fibers in the nonwoven web is indicated by the weight loss in%. Extensive or complete removal of the sulfopolyester from the bicomponent fibers was observed at temperatures of 33 ° C or above. If hydroentangling is used to produce a nonwoven network of these bicomponent fibers comprising the present sulfopolyester polymer of Example 8, one would expect that the sulfopolyester polymer would be largely or completely removed by means of the water jets of hydroentangled, if the water temperature is above room temperature. If removal of very little of the sulfopolyester polymer from these bicomponent fibers is desired during the hydroentangling step, a lower water temperature, less than about 25 ° C, should be used.

ES 2 403 114 T3

Example 10 (Reference Example)

A sulfopolyester polymer was prepared with the following diacid and diol composition: diacid composition (71 mol% terephthalic acid, 20 mol% isophthalic acid and 9 mol% 5- (sodium sulfo) isophthalic acid) and a diol composition (60% by mole of ethylene glycol and 40% by mole of diethylene glycol). The sulfopolyester was prepared by means of polyesterification at elevated temperature under vacuum. The esterification conditions were controlled to produce a sulfopolyester having an inherent viscosity of about 0.31. The melt viscosity of this sulfopolyester was measured and found within the range of about 3000-4000 poise at 240 ° C and 1 rad / s shear rate.

Example 11 (Reference Example)

The sulfopolyester polymer of Example 10 was spun into bicomponent tart fibers and a nonwoven web according to the same procedure as described in Example 9. The primary extruder (A) fed the melt of Eastman F61HC PET polyester to form large segment cuts in the segmented pie structure. The extrusion zones were adjusted to melt the PET penetrating the die die at a temperature of 285 ° C. The secondary extruder (B) processed the sulfopolyester polymer of Example 10 which was fed at a melt temperature of 255 ° C into the die die. The melt production rate per hole was 0.6 g / min. The volume ratio of PET to sulfopolyester in the extruded bicomponent fractions was adjusted to 70/30 which represents the weight ratio of about 70/30. The cross-section of the extruded bicomponent fractions showed PET wedge-shaped domains, with the sulfopolyester polymer acting to separate these domains.

The extruded bicomponent fractions were melt extracted using the same suction device assembly as used in Comparative Example 8 to produce the bicomponent fiber. The maximum available air pressure in the suction device, with no breakage of the bicomponent fibers during extraction, was 45 psi (310.3 kPa). Using air at a pressure of 45 psi (310.3 kPa) the extruded bicomponent fractions were extracted to give bicomponent fibers, with a denier value in spun form of approximately 1.2, exhibiting the bicomponent fibers a diameter of approximately 11-12 microns when viewed under the microscope. The speed during the melt extraction process was calculated to be about 4500 m / min.

The bicomponent fibers were warped into nonwoven webs having weights of 140 gsm and 110 gsm. The shrinkage of the nets was measured by conditioning the material in a forced air oven for five minutes at 120 ° C. The area of ​​the non-woven nets after shrinkage was 29% of the starting areas of the nets.

Microscopic examination of the cross-section of the melt-drawn fibers and of the fibers taken from the nonwoven web showed a very well segmented pie structure, in which the individual segments were clearly defined and exhibited similar size and shape. . The PET segments were completely separated from each other so as to form eight pie-cut PET monocomponent fibers after removal of the sulfopolyester from the bicomponent fiber.

The nonwoven net, which had a cloth weight of 110 gsm, was immersed for eight minutes in a static deionized water bath at various temperatures. The immersed nonwoven net was dried and the percentage weight loss due to immersion in deionized water at various temperatures was measured as shown in Table 5.

Table 5

<td>Immersion Temperature</td><td>36 ° C</td><td>41 ° C</td><td>46 ° C</td><td>51 ° C</td><td>56 ° C</td><td>72 ° C</td>

<td>Nonwoven Net Weight Loss (%)</td><td> 1,1</td><td> 2,2</td><td> 14,4</td><td> 25,9</td><td> 28,5</td><td> 30,5</td>

The sulfopolyester polymer dissipated very easily in deionized water at temperatures above about 46 ° C, the removal of the sulfopolyester polymer from the fibers being very extensive or complete at temperatures above 51 ° C, as shown by means of weight loss. A weight loss of approximately 30% represented a complete removal of the sulfopolyester from the bicomponent fibers of the nonwoven web. If hydroentangling is used to process this nonwoven network of bicomponent fibers comprising this sulfopolyester, it would be expected that the polymer would not be extensively removed by hydroentangling water jets at temperatures below 40 °. C.

Example 12 (Reference Example)

The nonwoven nets of Example 11 having basis weights of 140 gsm and 110 gsm were hydroentangled using a hydroentangling apparatus manufactured by Fleissner, GmbH, Egelsbach, Germany. The machine had five total hydro-entangling stations, in which three groups of jets were in contact with the upper side of the nonwoven web and two groups of jets were in contact with the side.

ES 2 403 114 T3 opposite of the non-woven net. The water jets comprised a series of fine holes approximately 100 microns in diameter machined into two two foot wide jet bands. The water pressure of the jets was adjusted to 60 bar (Jet Band No. 1), 190 bar (Jet Band No. 2 and 3) and 230 bar (Jet Band No. 4 and 5). During the hydroentangling process, the water temperature of the jets was found to be within the range of about 40-45 ° C. The nonwoven cloth leaving the hydroentangling unit was tightly bound. The continuous fibers were knotted together to produce a hydroentangled nonwoven cloth with high tear resistance when stretched in both directions.

The hydroentangled nonwoven fabric was then attached to a draw frame comprising a rectangular frame with a series of pins around its periphery. The cloth was attached to the pins to prevent shrinkage of the cloth on heating. The rack with the cloth sample was placed in a forced air oven for three minutes at 130 ° C to cause the cloth to heat set while its shrinkage was restricted. After heat setting, the conditioned cloth was cut to give a test sample of measured size, and the sample was conditioned at 130 ° C without any restriction by the draw frame. The dimensions of the hydroentangled nonwoven cloth were measured after the present conditioning and only minimal shrinkage was observed (&lt;0.5% reduction in dimensions). It was evident that the heat setting of the hydroentangled nonwoven was sufficient to produce a dimensionally stable nonwoven.

The hydro-entangled nonwoven cloth, after undergoing heat setting as described above, was washed with deionized water at 90 ° C to remove the sulfopolyester polymer and leave the remaining one-component PET fiber segments on the hydro-entangled cloth. After repeated washes, the dry cloth exhibited a weight loss of approximately 26%. Washing of the nonwoven net prior to hydroentangling demonstrated a 31.3% weight loss. Therefore, the hydroentangling process removed some of the sulfopolyester from the nonwoven web, but this amount was relatively small. In order to lighten the amount of sulfopolyester removed during hydroentangling, the water temperature of the hydroentangling jets should be lowered below 40 ° C.

The sulfopolyester of Example 10 was found to provide segmented pie fibers with good segment distribution in which the non-water dispersible polymer segments formed individual fibers of similar size and shape upon removal of the sulfopolyester polymer. The rheology of the sulfopolyester was appropriate to allow melt extraction of extruded bicomponent fractions at high speeds in order to achieve fine denier bicomponent fibers with denier value in spun form as low as about 1.0. These bicomponent fibers can be warped into a nonwoven web, which could be hydroentangled without experiencing significant loss of the sulfopolyester polymer in order to produce the nonwoven cloth. The nonwoven cloth produced by hydroentangling the nonwoven web exhibited high strength and could be heat set at temperatures of about 120 ° C or more, to produce a nonwoven cloth with excellent dimensional stability. The sulfopolyester polymer was removed from the hydroentangled nonwoven in a washing step. This resulted in a strong nonwoven product with a lighter cloth weight, much greater flexibility, and smoother handling. The one-component PET fibers of the present wedge-shaped nonwoven product were formed and exhibited a mean denier value of about 0.1.

Example 13 (Reference Example)

A sulfopolyester polymer was prepared with the following diacid and diol composition: diacid composition (69% by moles of terephthalic acid, 22.5% of isophthalic acid, and 8.5% by moles of 5- (sodium sulfo) isophthalic acid ) and a diol composition (65% by mole of ethylene glycol and 35% by mole of diethylene glycol). The sulfopolyester was prepared by means of high temperature polyesterification under vacuum. The esterification conditions were controlled to produce a sulfopolyester having an inherent viscosity of about 0.33. The melt viscosity of the present sulfopolyester was measured to be within the range of about 3000-4000 poise at 240 ° C and 1 rad / s shear rate.

Example 14 (Reference Example)

The sulfopolyester polymer of Example 13 was spun to give a cross-sectional pattern of islands in the sea with 16 islands in a spunbonded line. The primary extrusion device (A) fed the Eastman F61HC PET polyester melt to form the islands of the island structure in the sea. The extrusion zones were adjusted to melt the PET entering the die die at a temperature of approximately 290 ° C. The secondary extruder (B) processed the sulfopolyester polymer of Example 13 which was fed at a melt temperature of about 260 ° C into the die die. The volume ratio of PET to sulfopolyester in the extruded bicomponent fractions was adjusted to 70/30, representing a weight ratio of about 70/30. The melt production rate through the die was 0.6 g / hole / minute. The cross-section of the extruded bicomponent fractions showed round-shaped island PET domains, with the sulfopolyester polymer acting to separate these domains.

The extruded bicomponent fractions were melt extracted using a suction device assembly. The maximum available air pressure in the suction device, without producing

ES 2 403 114 T3 breakage of the bicomponent fibers during melt extraction was 50 psi (344.7 kPa). Using air at a pressure of 50 psi (344.7 kPa) the extruded bicomponent fractions were extracted to give bicomponent fibers, with a denier value in spun form of about 1.4, exhibiting the bicomponent fibers a diameter of approximately 12 microns when viewed under the microscope. The speed during the extraction process was calculated to be approximately 3900 m / min.

Example 15 (Reference Example)

The sulfopolyester polymer of Example 13 was spun to form island cross-section bicomponent fibers in the sea with 64 island fibers using a bicomponent extrusion line. The primary extrusion device (A) fed the Eastman F61HC PET polyester melt to form to form the islands of the island fiber cross-sectional structure in the sea. The secondary device fed the melt of the sulfopolyester polymer to form the sea of ​​the bicomponent fiber of islands in the sea. The inherent viscosity of the polyester was 0.61 dL / g, while the melt viscosity of the dry sulfopolyester was approximately 7000 poise measured at 240 ° C and a stress rate of 1 rad / s using the measurement procedure of melt viscosity described above. These bicomponent fibers from islands in the sea were prepared using a spinneret with 198 holes and a throughput rate of 0.85 g / minute / hole. The polymer ratio between island polyester and sea sulfopolyester was 65% to 35%. These bicomponent fibers were spun using an extrusion temperature of 280 ° C for the polyester component and 260 ° C for the sulfopolyester component. The bicomponent fiber contains a multiplicity of filaments (198 filaments) and was melt spun at a speed of approximately 530 meters / minute, forming filaments with a nominal denier value per filament of approximately 14. A finishing solution of 24% by weight of Goulston Technologies PT 769 finish to bicomponent fiber using a contact roll applicator. Subsequently, the bicomponent fiber filaments were subjected to in-line extraction using a set of two traction rollers, heated to 90 ° C and 130 ° C, respectively, operating the final extraction roller at a speed of approximately 1750 meters / minute, to generate a filament draw ratio of approximately 3.3X, forming the bicomponent strands drawn from islands in the sea with a nominal denier value per strand of about 4.5 or an average diameter of about 25 microns. These filaments comprised islands of polyester microfibers having a mean diameter of approximately 2.5 microns.

Example 16 (Reference Example)

The offshore island-type bicomponent fibers of Example 15 were cut to yield short-length fibers 3.2 millimeters and 6.4 millimeters in length, thereby producing short-length bicomponent fibers with configurations of cross section of 64 islands in the sea. These short bicomponent fibers formed islands of polyester in a sea of ​​water dispersible sulfopolyester polymer. The island and sea cross-sectional distribution was essentially uniform along the length of these short bicomponent fibers.

Example 17 (Reference Example)

The offshore island-type extracted bicomponent fibers of Example 15 were immersed in soft water for approximately 24 hours and subsequently cut to yield fibers of 3.2 millimeter length and 6.4 millimeter cut lengths. The water dispersible sulfopolyester was at least partially emulsified prior to cutting to give short length fibers. Therefore, the partial separation of the islands from the sea component was carried out, thereby producing bicomponent fibers, of the type of islands in the sea, of short length and partially emulsified.

Example 18

The short length, island-in-the-sea type bicomponent fibers of Example 16 were washed using soft water at 80 ° C to remove the water dispersible sulfopolyester sea component, thereby releasing the polyester microfibers that made up the island component of bicomponent fibers. The washed polyester microfibers were rinsed with soft water at 25 ° C to remove essentially most of the sea component. Optical microscopic observation of the washed polyester microfibers showed a mean diameter of approximately 2.5 microns and lengths of 3.2 and 6.4 millimeters.

Example 19

The short length, partially emulsified, island-in-the-sea type bicomponent fibers of Example 17 were washed using soft water at 80 ° C to remove the water dispersible sulfopolyester sea component, thereby releasing the polyester microfibers. which constituted the island component of the fibers. The washed polyester microfibers were rinsed with 25 ° C water to remove essentially most of the sea component. Light microscopic observation of the washed polyester microfibers showed polyester microfibers with a mean diameter of approximately 2.5 microns and lengths of 3.2 and 6.4 millimeters.

ES 2 403 114 T3

Comparative Example 20

Hand-made and wet-warped sheets were prepared using the following procedure. They were placed

7.5 g of Albacel Southern Bleached Softwood Kraft (SBSK) from International Paper, Memphis, Tennessee, USA, and 188 g of room temperature water in a 1000 ml pulping device and subjected to extraction of pulp for 30 seconds at 7000 rpm to produce a pulp mix. This pulp was transferred to an 8 liter metal beaker together with 7312 g of water at room temperature to obtain a consistency of 0.1% (7500 g of water and 7.5 g of fibrous matter) in order to prepare a pulp suspension. This pulp suspension was stirred using a paddle mixing device for 60 seconds. The procedure for the preparation of the hand-made sheet from this pulp suspension was as shown below. The pulp suspension was poured into a 25 cm x 30 cm hand-made sheet mold while stirring. The conical seat controlled valve was pulled, and the pulp fibers were allowed to drain over a sieve to form a hand-made sheet. 750 grams per square meter (gsm) blotting paper was placed on top of the hand-formed and hand-made sheet, and the blotting paper was pressed against the hand-made sheet. The sieve frame was washed and inverted onto a clean release liner and allowed to stand for 10 minutes. The screen was separated vertically upward from the hand-formed and hand-made sheet. Two sheets of 750 gsm blotting paper were placed on top of the hand-formed and hand-made sheet. The hand-made sheet was dried along with the three blotting papers using a Norwood Drying Device at about 88 ° C for 15 minutes. A blotter was removed leaving a blotter on each side of the hand-made sheet. The hand-made sheet was dried using a Williams Drying Device at 65 ° C for 15 minutes. Subsequently, the hand-made sheet was dried for 12 to 24 hours using a 40 kg drying press. The blotting paper was removed to obtain the hand-made dry sheet sample. The hand-made sheet was cut to dimensions 21.6 cm by 27.9 cm for testing.

Comparative Example 21

Hand-made and wet-warped sheets were prepared using the following procedure. They were placed

7.5 g of Albacel Southern Bleached Softwood Kraft (SBSK) from International Paper, Memphis, Tennessee, USA, 0.3 g of cationic, quaternary and pre-gelatinized potato starch Solivitose N from Avebe, Foxhol, The Netherlands and 188 g of room temperature water in a 1000 ml pulping device and pulped for 30 seconds at 7000 rpm to produce a mixture in the form of pulp. This pulped mixture was transferred to an 8 liter metal beaker along with 7312 g of room temperature water to obtain a consistency of approximately 0.1% (7500 g of water and 7.5 g of fibrous matter). ) in order to prepare a pulp suspension. This pulp suspension was stirred using a paddle mixing device for 60 seconds. The rest of the procedure for the preparation of the sheet made by hand from this pulp suspension was the same as in Example 20.

Example 22

Hand-made and wet-warped sheets were prepared using the following procedure. 6.0 g of Albacel Southern Bleached Softwood Kraft (SBSK) from International Paper, Memphis, Tennessee, USA, 0.3 g of cationic, quaternary and pre-gelatinized potato starch Solivitose N from Avebe, Foxhol, were placed. Netherlands, 1.5 grams of the 3.2 millimeter cut-length island-in-sea fibers from Example 16 and 188 g of room temperature water in a 1000 ml pulping device and pulping for 30 seconds at 7000 rpm to produce a mixed suspension of fibers. This mixed fiber suspension was heated at 82 ° C for 10 seconds to emulsify and remove the water dispersible sulfopolyester component in the island-in-the-sea type fibers and release the polyester microfibers. The mixed fiber suspension was then filtered to produce a sulfopolyester dispersion comprising the sulfopolyester and a microfiber-containing blend containing pulp fibers and polyester microfibers. Subsequently, the microfiber-containing mixture was washed using 500 g of room temperature water to further remove the water-dispersible sulfopolyester from the microfiber-containing mixture. The mixture containing microfibers was transferred into an 8 liter metal beaker with 7312 grams of water at room temperature to obtain a consistency of approximately 0.1% (7500 g of water and 7.5 g of fibrous material). in order to produce a suspension containing microfibers. The suspension containing microfibers was agitated using a high speed paddle mixing device for 60 seconds. The remainder of the procedure for producing the hand-made sheet from this microfiber-containing suspension is the same as in Example 20.

Comparative Example 23

Hand-made and wet-warped sheets were prepared using the following procedure. They were placed

7.5g MicroStrand 475-106 micro fiberglass available from Johns Manville, Denver, Colorado, USA, 0.3g Solivitose N pre-gelatinized quaternary cationic potato starch from Avebe, Foxhol, Countries Basses and 188 g of room temperature water into a 1000 ml pulping device and pulped for 30 seconds at 7000 rpm to produce a fiberglass mixture. The fiberglass mixture was transferred into an 8 liter metal beaker with 7312 grams of water at room temperature to obtain a consistency of approximately 0.1% (7500 g of water and 7.5 g of fibrous material ) with the purpose of

ES 2 403 114 T3 produce a glass fiber suspension. The fiberglass suspension was agitated using a high speed paddle mixing device for 60 seconds. The remainder of the procedure for producing the hand-made sheet from this fiberglass suspension is the same as in Example 20.

Example 24

Hand-made and wet-warped sheets were prepared using the following procedure. They were placed

3.8 g of MicroStrand 475-106 micro fiberglass available from Johns Manville, Denver, Colorado, USA, 3.8 g of Example 16 fibers, islands in the sea type and cut-off length of 3.2 millimeters, 0.3 g of cationic, quaternary and pre-gelatinized potato starch Solivitose N from Avebe, Foxhol, Netherlands and 188 g of room temperature water in a 1000 ml pulping device and pulping for 30 seconds at 7000 rpm to produce a mixed suspension of fibers. This mixed fiber suspension was heated at 82 ° C for 10 seconds to emulsify and remove the water dispersible sulfopolyester component in the island-in-the-sea bicomponent fibers and release the polyester microfibers. The mixed fiber suspension was then filtered to produce a sulfopolyester dispersion comprising the sulfopolyester and a microfiber-containing blend containing glass microfibers and polyester microfibers. Subsequently, the microfiber-containing mixture was washed using 500 g of room temperature water to further remove the sulfopolyester from the microfiber-containing mixture. The mixture containing microfibers was transferred into an 8 liter metal beaker with 7312 grams of water at room temperature to obtain a consistency of approximately 0.1% (7500 g of water and 7.5 g of fibrous material). in order to produce a suspension containing microfibers. The suspension containing microfibers was agitated using a high speed paddle mixing device for 60 seconds. The remainder of the procedure for producing the hand-made sheet from this microfiber-containing suspension is the same as in Example 20.

Example 25

Hand-made and wet-warped sheets were prepared using the following procedure. They were placed

7.5 g of the fibers of Example 16, of the islands in the sea type and 3.2 millimeter cut length, 0.3 g of cationic, quaternary and pre-gelatinized potato starch Solivitose N from Avebe, Foxhol, Netherlands and 188 g of room temperature water into a 1000 ml pulping device and pulped for 30 seconds at 7000 rpm to produce a mixed suspension of fibers. This mixed fiber suspension was heated at 82 ° C for 10 seconds to emulsify and remove the water dispersible sulfopolyester component on the island-in-the-sea type fibers and release the polyester microfibers. The mixed fiber suspension was then filtered to produce a dispersion of sulfopolyester and polyester microfibers. The sulfopolyester dispersion consisted of water dispersible sulfopolyester. The polyester microfibers were washed using 500 g of room temperature water to further remove the sulfopolyester from the polyester microfibers. These polyester fibers were transferred to an 8 liter metal beaker together with 7312 grams of water at room temperature to obtain a consistency of approximately 0.1% (7500 g of water and 7.5 g of fibrous material) with the in order to produce a microfiber suspension. This microfiber suspension was agitated using a high speed paddle mixing device for 60 seconds. The remainder of the procedure for producing the hand-made sheet from this microfiber suspension is the same as in Example 20.

The hand-made sheet samples of Examples 20-25 were tested and the properties are shown in the following table.

ES 2 403 114 T3

<td>Voltage x stretching</td><td>h-</td><td></td><td> 20</td><td>CO</td><td>OR</td><td> 44</td>

<td>Stretch to Break (%)</td><td>h-</td><td>h-</td><td>OR</td><td>IT</td><td>h-</td><td>IT</td>

<td>Tensile Strength (kg / 15 mm)</td><td>or</td><td>IT</td><td> 2,2</td><td> 0,2</td><td></td><td>o'e</td>

<td>Porosity Greiner (s / 100 cc)</td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Density (g / cc)</td><td> 0,22</td><td> 0,22</td><td> 0,33</td><td> 0,15</td><td> 0,22</td><td> 0,26</td>

<td>Thickness of Sheet Made to Hand (mm)</td><td> 0,45</td><td> 0,44</td><td> 0,30</td><td> 0,68</td><td> 0,45</td><td> 0,38</td>

<td>Base Weight (gsm)</td><td> 94</td><td>CO</td><td>CO</td><td> 103</td><td> 104</td><td> 80</td>

<td>Composition</td><td>100% SBSK</td><td>SBSK + 4% off starch</td><td>80% SBSK + starch + 20% microfibers 3.2mm polyester from Example 19</td><td>100% Glass Microstrand 475-106 + starch</td><td>50% Glass Microstrand 475-106 + 50% off microfibers 3.2mm polyester from Example 19 + Starch</td><td>100% polyester microfibers 3.2mm from Example 19</td>

<td>Example Number</td><td> 20</td><td>CXI</td><td> 22</td><td> 23</td><td> 24</td><td> 25</td>

ES 2 403 114 T3

The basis weight of the hand-made sheet was determined by weighing the hand-made sheet and calculating the weight in grams per square meter (gsm). The thickness of the hand-made sheet was measured using an Ono Sokki EG-233 thickness gauge and was reported as thickness in millimeters. Density was calculated as weight in grams per cubic centimeter. Porosity was measured using a Greiner Porosity Gauge with a 1.9 x 1.9 cm square opening head and a 100 cc capacity. Porosity is presented as the mean time in seconds (4 replicates) for 100 cc of water to pass through the sample. Tensile properties were measured using an Instron Model TM for six 30mm x 105mm test bars. An average of six measurements is presented for each sample. It can be seen from these test data that a significant improvement in the tensile properties of the wet-warped fibrous structures is obtained by the addition of the polyester microfibers of the present invention.

Example 26 (Reference Example)

The sulfopolyester polymer of Example 13 was spun into bicomponent fibers, cross-sectional islands in the sea with 37 island fibers using a bicomponent extrusion line. The primary extrusion device fed Eastman F61HC polyester to form the islands of the cross-sectional structure of islands in the sea. The secondary extrusion device fed the water dispersible sulfopolyester polymer to form the sea of ​​the island type bicomponent fiber in the sea. The inherent viscosity of the polyester was 0.61 dL / g while the melt viscosity of the dry sulfopolyester was approximately 7000 poise measured at 240 ° C and a stress rate of 1 rad / s using the viscosity measurement procedure. previously described melt. These island-type bicomponent fibers were prepared in the sea using a 72 hole spinneret and a throughput rate of 1.15 g / minute / hole. The polymer ratio between island polyester and marine sulfopolyester was 2 to 1. These bicomponent fibers were spun at an extrusion temperature of 280 ° C for the polyester component and 255 ° C for the sulfopolyester component. dispersible in water. This bicomponent fiber contained a multiplicity of filaments (198 filaments) and was melt spun at a speed of approximately 530 meters / minute to form filaments with a nominal denier value per filament of 19.5. A finishing solution of 24% by weight of finishing PT 769 from Golston Technologies was applied to the bicomponent fiber using a contact roll applicator. Subsequently, the bicomponent fiber filaments were subjected to in-line extraction using a set of two traction rolls, heated to 95 ° C and 130 ° C, respectively, operating the final extraction roll at a speed of approximately 1750 meters / minute, to generate a filament draw ratio of approximately 3.3X, the bicomponent strands being drawn from islands in the sea with a nominal denier value per strand of about 5.9 or an average diameter of about 29 microns. These filaments comprised islands of polyester microfibers having a mean diameter of approximately 3.9 microns.

Example 27 (Reference Example)

The offshore island-type bicomponent fibers of Example 26 were cut to yield short-length bicomponent fibers of 3.2 millimeters and 6.4 millimeters in chopped length, thereby producing short-length fibers with configurations. cross section of 37 islands in the sea. These fibers comprised islands of polyester and a sea of ​​water dispersible sulfopolyester polymers. The island and sea cross-sectional distribution was essentially uniform along the length of these bicomponent fibers.

Example 28

The island-type short fibers were washed in the sea of ​​Example 27 using soft water at 80 ° C to remove the water dispersible sulfopolyester sea component, thereby releasing the polyester microfibers that constituted the island component of the fibers. bicomponent. The washed polyester microfibers were rinsed using soft water at 25 ° C to remove essentially most of the sea component. Light microscopic observation of the washed polyester microfibers showed a mean diameter of approximately 3.9 microns and lengths of 3.2 and 6.4 millimeters.

Example 29 (Reference Example)

The sulfopolyester polymer of Example 13 was spun to form island-type cross-section bicomponent fibers in the sea with 37-island fibers using a bicomponent extrusion line. The primary extrusion device fed the polyester to form the islands of the island-like cross-sectional structure in the sea. The secondary feeder fed the water dispersible sulfopolyester polymer to form the sea of ​​the bicomponent fiber of islands in the sea. The inherent viscosity of the polyester was 0.52 dL / g, while the melt viscosity of the dry water-dispersible sulfopolyester was approximately 3,500 poise measured at 240 ° C and a stress rate of 1 rad / s using the procedure melt viscosity measurement previously described. These island-type bicomponent fibers were prepared in the sea using two rows with 175 holes each and a production rate of 1.0 g / minute / hole. The polymer ratio between island polyester and marine sulfopolyester was 70% to 30%. These bicomponent fibers were spun using an extrusion temperature of 280 ° C for the polyester component and 255 ° C for the sulfopolyester component. The bicomponent fibers had a multiplicity of filaments (350 filaments) and were melt spun at a speed of approximately 1000 meters / minute using the pick-up roll heated to 100 ° C,

ES 2 403 114 T3 forming filaments with a nominal denier value per filament of approximately 9 and an average fiber diameter of approximately 36 microns. A finishing solution of 24% by weight of finishing PT 769 was applied to the bicomponent fiber using a contact roll applicator. The bicomponent fiber filaments were combined and then 3.0x were extracted in an extraction line at an extraction roller speed of 100 m / minute and a temperature of 38 ° C, forming island-type extracted bicomponent filaments in the sea with an average denier value per filament of approximately 3 and an average diameter of approximately 20 microns. These bicomponent fibers extracted as islands in the sea were cut into short length fibers approximately 6.4 millimeters in length. These short, island-in-the-sea, bicomponent fibers were made up of polyester microfiber islands with a mean diameter of approximately 2.8 microns.

Example 30 (Reference Example)

The short-length, island-type, bicomponent fibers in the sea of ​​Example 29 were washed using soft water at 80 ° C to remove the water-dispersible sulfopolyester sea component, thereby releasing the polyester microfibers that made up the water. island component of fibers. The washed polyester microfibers were rinsed with soft water at 25 ° C to remove essentially most of the sea component. Light microscopic observation of the washed polyester microfibers showed a mean diameter of approximately 2.8 microns and lengths of approximately 6.4 millimeters.

Example 31

Hand-made stock sheets of wet-warped microfibers were prepared using the following procedure. 56.3 grams of island-type bicomponent fibers of 3.2 millimeter cut length were introduced into the sea from Example 16, 2.3 grams of pregelatinized, quaternary, cationic potato starch Solivitose N from Avebe, Foxhol, Netherlands, and 1410 grams of room temperature water, in a 2-liter beaker to produce a fiber suspension. The suspension was stirred. A quarter amount of this fiber suspension, approximately 352 ml, was introduced into a 1000 ml pulping device and pulped for 30 seconds at 7000 rpm. This fiber suspension was heated to 82 ° C for 10 seconds to emulsify and remove the water dispersible sulfopolyester component from the island-type bicomponent fibers in the sea and release the polyester microfibers. The mixed fiber suspension was then filtered to produce a dispersion of sulfopolyester and polyester microfibers. These polyester microfibers were washed using 500 grams of room temperature water to further remove the sulfopolyester from the polyester microfibers. Sufficient room temperature water was added to produce 352 ml of microfiber suspension. This microfiber suspension was subjected to re-pulp extraction for 30 seconds at 7000 rpm. These microfibers were transferred into an 8 liter metal beaker. The remaining three-quarters of the fiber suspension were similarly pulped, washed, rinsed, re-pulped, and transferred to the 8-liter metal beaker. Next, 6090 grams of water was added at room temperature to obtain a consistency of about 0.49% (7500 grams of water and 36.6 grams of polyester microfibers) to produce a microfiber suspension. The microfiber suspension was agitated using a high speed paddle mixing device for 60 seconds. The remainder of the procedure for preparing the hand-made sheet from this microfiber suspension was the same as in Example 20. The hand-made microfiber stockpile sheet with basis weight of about 490 gsm consisted of microfibers. of polyester with an average diameter of approximately

2.5 microns and an average length of approximately 3.2 millimeters.

Example 32

Hand-made and wet-warped sheets were prepared using the following procedure. They were placed

7.5 g of reserve sheet, made by hand and of polyester microfibers of Example 31, 0.3 g of cationic, quaternary and pre-gelatinized potato starch Solivitose N from Avebe, Foxhol, The Netherlands and 188 g of water at temperature ambient in a 1000 ml pulping device and pulped for 30 seconds at 7000 rpm. The microfibers were transferred into an 8 liter metal beaker along with 7312 g of room temperature water to obtain a consistency of approximately 0.1% (7500 grams of water and 7.5 grams of fibrous material) with the in order to produce a microfiber suspension. The microfiber suspension was agitated using a high speed paddle mixing device for 60 seconds. The rest of the procedure for the preparation of the hand-made sheet from this microfiber suspension was the same as that of Example 20. 100 gsm of hand-made and wet-warped sheet of polyester microfibers were obtained, with a diameter medium about 2.5 microns.

Example 33 (Reference Example)

The two-component, island-in-the-sea, 6.4 millimeter cut-length fibers from Example 29 were washed using soft water at 80 ° C to remove the water-dispersible sulfopolyester sea component, thereby releasing the Polyester microfibers that constituted the island component of the bicomponent fibers. The washed polyester microfibers were rinsed with soft water at 25 ° C to remove essentially most of the

ES 2 403 114 T3 sea component. Light microscopic observation of the washed polyester microfibers showed a mean diameter of approximately 2.5 microns and lengths of 6.4 millimeters.

Example 34

The short-length, island-in-the-sea type bicomponent fibers of Example 16, Example 27 and Example 29 were washed separately using soft water at 80 ° C containing approximately 1% by weight, based on the weight of the bicomponent fibers of ethylenediaminetetraacetic acid sodium salt (Na4EDTA) from Sigma-Aldrich Company, Atlanta, Georgia, to remove the dispersible sulfopolyester sea component, thus releasing the polyester microfibers that constituted the island components of the bicomponent fibers. The addition of at least one water softening agent, such as Na4EDTA, contributes to the removal of the water dispersible sulfopolyester polymer from the bicomponent island-type fibers in the sea. The washed polyester microfibers were rinsed using soft water at 25 ° C to remove essentially most of the sea component. Optical observation of the washed polyester microfibers showed excellent release and separation of the polyester microfibers. The use of a water softening agent, such as Na4EDTA, avoids any ion exchange of Ca⁺⁺ in the sulfopolyester that may adversely affect the ability of the sulfopolyester to undergo dispersion in water. Typical soft water may contain a concentration of Ca ions⁺⁺ up to 15 ppm. It is desirable that the soft water used in the process described herein has an essentially zero concentration of Ca⁺⁺ and other multi-valent ions or, alternatively, use a sufficient amount of water softening agent, such as Na4EDTA, in order to bind those Ca ions⁺⁺ and the other multi-valent ions. These polyester microfibers can be used in the preparation of wet warped sheets using the procedures of the examples previously described.

Example 35

The short length, island-in-the-sea, bicomponent fibers of Example 16 and Example 27 were processed separately using the following procedure. 17 grams of cationic, quaternary, pre-gelatinized potato starch Solivitose N from Avebe, Foxhol, The Netherlands, was added to the distilled water. After the starch was completely dissolved or hydrolyzed, then 429 grams of the short length, island-in-the-sea bicomponent fibers were slowly added to the distilled water to produce a fiber suspension. A Williams Rotary Continuous Feed Refiner (5 inches (12.7 cm) diameter) was fired to refine or blend the fiber suspension to provide sufficient shear action to separate the water dispersible sulfopolyester from the microfibers. Of polyester. The contents of the reserve container were poured into a 24 liter stainless steel container, and the lid was closed. The stainless steel container was placed in an oven and heated until the fiber suspension began to boil at approximately 97 ° C in order to remove the sulfopolyester component from the island-type fibers in the sea and release the microfibers from polyester. Once the fiber suspension reached the boil, it was stirred with a manual stirring paddle. The contents of the stainless steel container were poured into a 27 inch (68.6 cm) x 15 inch (38.1 cm) x 6 inch (15.24 cm) deep False Bottom Knuche with a No. mall 30 to produce a dispersion of sulfopolyester and polyester microfibers. The sulfopolyester dispersion comprised water and a water dispersible sulfopolyester. The polyester microfibers were rinsed in the Knuche for 15 seconds with 10 liters of soft 17 ° C water, and squeezed to remove excess water.

20 grams of polyester microfiber (dry fiber base) was added to 2000 ml of water at 70 ° C and stirred using a 2 liter hydro-pulping device, with 3/4 horsepower and 3000 rpm. , manufactured by Hermann Manufacturing Company for 3 minutes (9,000 revolutions) to prepare a fiber suspension of 1% consistency. Hand-made sheets were prepared using the procedure previously described in Example 20.

Optical and scanning electron microscope observation of these hand-made sheets showed excellent separation and formation of polyester microfibers.