Hot melt adhesive composition based on a random copolymer of isotactic polypropylene

ES 2 388 971 T3

DESCRIPTION

Hot melt adhesive composition based on an isotactic polypropylene random copolymer and a secondary polymer

Field of the invention

[0001] This invention relates to novel stereospecific, predominantly semi-crystalline, isotactic random copolymers of polypropylene (RCP) hot melt adhesive compositions. More particularly, this invention relates to adhesive compositions that find utility in carton / carton sealing and in the manufacture of disposable nonwoven articles, such as diapers and feminine hygiene products. The adhesive compositions are particularly useful as an elastic fastener and as a construction adhesive in the assembly of disposable nonwovens.

Background of the invention

[0002] Hot melt adhesives typically exist as solid masses at room temperature and can be turned into a flowable liquid by the application of heat. These adhesives are particularly useful in the manufacture of a variety of disposable goods, where the bonding of various substrates is often necessary. Specific applications include disposable diapers, hospital padding, feminine sanitary napkins, briefs, surgical drapes, and adult incontinence diapers, collectively known as disposable nonwovens. Other diversified applications have involved paper products, packaging materials, ribbons and labels. In most of these applications, the hot melt adhesive is heated to its molten state and then applied to a substrate. A second substrate is immediately contacted and compressed against the first. The adhesive solidifies on cooling to form a strong bond. The main advantage of hot melt adhesives is the absence of a liquid vehicle, such as water or solvent-based adhesives, thus eliminating the costly process associated with solvent removal.

[0003] For many applications, hot melt adhesives are often extruded directly onto a substrate as a thin film using piston or gear pump equipment. In this case, the substrate is brought into intimate contact with the hot die under pressure. The temperature of the die must be kept well above the melting point of the adhesive, which is typically between 150 and 200 ° C. For some applications, particularly to make nonwovens, the bonding of delicate and heat sensitive substrates, such as fine gauge polyethylene films, is often involved. Direct contact between the film and the die, in these cases, should be avoided to prevent the film from burning or distorting. Various application methods have been developed through which a hot melt adhesive can be spray coated with the aid of compressed air onto a remote substrate. These non-contact coating techniques include spiral spraying and various forms of melt blowing methods. Therefore, direct contact between the coating head and the substrate is eliminated. All of the coating techniques in this document described above are well known to those skilled in the art and commercial equipment is readily available.

[0004] Spray coating techniques, however, place strict requirements on hot melt adhesives. The viscosity of the adhesives must be low enough, usually in the range of 2000 to 30,000 mPa.s (2,000 to 30,000 cP), preferably in the range of 2,000 to 15,000 mPa.s (2,000 to 15,000 cP) at the temperature of application. Many other physical factors, especially the rheological properties of the adhesive, come into play in determining the dispersibility of a hot melt. Most commercial hot melt products do not by themselves lead to spray applications. There are no theoretical models or accepted guidelines for predicting sprayability, and sprayability must be determined empirically with application equipment.

[0005] Syndiotactic polypropylene polymers (SPP) are known in the art. SPP polymers are stereospecific high molecular weight homopolymers of propylene or copolymers of propylene with other α-olefin monomers, such as ethylene, butene-1, or hexene-1. Syndiotactic polymers should not be confused with conventional crystalline polypropylenes and essentially amorphous atactic poly-α-olefins (APAO). These polymers differ from each other both in structure and in properties. Those skilled in the art are well aware that conventional crystalline polypropylenes have an isotactic molecular chain configuration. The isotactic configuration can be described as having methyl groups attached to the tertiary carbon atoms of successive monomer units on the same side of the hypothetical plane drawn through the main polymer chain. This type of stereochemical structure can be graphically illustrated using Fisher's projection formula as follows:

ES 2 388 971 T3

<img file="ES2388971T3_D0001.tif" />

[0006] Due to their high chain regularity, conventional isotactic polypropylenes (IPPs) are highly crystalline, with a crystallinity typically greater than 50% and a heat of fusion greater than 70 J / g. They are usually rigid materials that have a high density and a high melting point. Due to the absence of flexibility, an IPP polymer can only be used as a modifier in small amounts, typically about 2% to 5% by weight, in hot melt adhesive formulations. A typical conventional IPP typically has a melt index that is inversely related to weight average molecular weight, in the range of 0.5 to 200 g / 10 min as measured according to the ASTM D-1235 test method.

[0007] Another component known for use in a hot melt adhesive composition combination comprises an APAO polymer. APAO polymers are a family of essentially amorphous low molecular weight propylene homopolymers or copolymers of propylene with ethylene or butene or hexene. In contrast to the regular structures in IPP or SPP, APAOs have atactic molecular chains with methyl groups in successive monomer units, sterically randomly distributed on both sides of the hypothetical plane along the polymer chain. The stereo-configuration of the atactic APAO molecular chain can be graphically illustrated using the following Fisher projection formula:

<img file="ES2388971T3_D0002.tif" />

[0008] The stereo-chain structure of SPP is unequivocally different from that of IPP and APAO. In contrast to the isotactic chain configuration of IPP and the atactic chain configuration of APAO, the stereochemistry of SPP can be described as having tertiary methyl groups from the successive monomer units along the chain, arranged alternately on either side of the plane. hypothetical. The stereo configuration of SPP can be represented below:

<img file="ES2388971T3_D0003.tif" />

[0009] The stereoconfiguration of polypropylene can also be characterized quantitatively by C-13 NMR. In NMR nomenclature, a meso dyad of successive methyl groups on the same side of the plane, as in the case of IPP, is represented by the letter m. A racemic dyad of successive methyl groups on opposite sides of the plane, as in the case of SPP, is represented by the letter r. The percentage of mor defines the degree of polymeric tacticity, the sum of myr being equal to 100%. Thus, a perfect isotactic polypropylene will have 100% dyad m, while a perfect syndiotactic polypropylene will have 100% dyad r. This unique stereochemical structure of SPP results in an unusual and desirable combination of physical and mechanical properties, such as low density, low melting point, flexibility, and toughness. SPP polymers typically have an r-value equal to or greater than 70%, while the r-values ​​of conventional IPPs, by comparison, are generally in a smaller percentage range.

[0010] In addition to the difference in stereochemistry, SPPs are also easily distinguishable from IPPs and APAOs by their unique physical properties. Typical SPPs will have a melting point between 130 and 160 ° C, while crystalline IPPs typically have a melting point of about 176 ° C. APAOs, on the other hand, are usually predominantly amorphous, without a well-defined melting point, although some grades of commercial products can exhibit a very low degree of crystallinity. Another profound difference between SPP, IPP and APAO lies in their densities. The density of SPP is typically between 0.86 to 0.90 g / cm³, which is between those of IPP and APAO. IPPs have the highest density, ranging from 0.90 to 0.95 g / cm³ and the APAO, the smallest variation, from 0.85 to 0.87 g / cm³.

Due to their high melting point, high degree of crystallinity, and the absence of desirable physical and mechanical attributes, such as flexibility and toughness, conventional IPPs have not been used alone as the polymer base for adhesive applications. hot melt. An IPP-based hot melt adhesive would be too

ES 2 388 971 T3 brittle to offer acceptable bond strength, and would further require a high application temperature that works well beyond the melting point of the polymer.

[0012] Hot melt adhesives containing APAO, APAO / polyethylene (PE) blends, APAO / polybutene (PB) blends, or APAO / IPP blends are known in the art. These adhesives typically consist of an APAO or a combination of APAO mentioned earlier herein and a hydrocarbon-type adhesive. It is well known that APAO-based adhesives generally have poor cohesive strength, poor heat resistance, low bond strength at elevated temperature, and low shear values. APAOs have not found much use in disposable nonwoven applications, where a combination of high bond strength at a very low coating weight and easy processability by spray techniques is required. APAO-based adhesives typically lack such capabilities. Although various attempts have been made to address these problems by combining APAO with PE, PB, and conventional IPP, very often such modifications not only failed to rectify the problems, but also led to adverse side effects.

[0013] For example, Trotter et al. in US Patent No. 4,022,728, discloses a hot melt pressure sensitive composition comprising a mixture of the APAOs, a low molecular weight substantially amorphous elastomer, a liquid adherent, and a conventional crystalline polypropylene (IPP) in a amount up to 2% by weight. The composition is claimed to provide good adhesive properties at low temperatures.

[0014] Meyer et al. US Patent No. 4,120,916 discloses hot melt adhesive compositions comprising a combination of low molecular weight polyethylene, conventional polymer containing low molecular weight propylene and APAO. These adhesive compositions are said to offer a short open time and to be useful for bonding a paraffin modified corrugated board.

Lakshmanan et al., In US Patent No. 4,761,450, disclose a polymer blend useful as a hot melt adhesive comprising a low density ethylene polymer, a copolymer of butene-1 with ethylene or propylene , a hydrocarbon adherent and a low molecular weight polymer consisting of a liquid low molecular weight polybutylene, an amorphous polypropylene, and a mixture thereof.

[0016] Lakshmanan et al., In US Patent No. 5,478,891, also disclose combination compositions containing (a) a high molecular weight copolymer of ethylene with an α-olefin having at least 4 carbons and (b) an amorphous polypropylene or amorphous polyolefin. The components of the blends are described as having a molecular weight range between 300 and 6000. The polymer blends are claimed to be useful for hot melt adhesives, coatings, sealants, asphalt modifiers, and plastic additives.

[0017] Ryan discloses in US Patent No. 5,745,573 an APAO-based hot melt adhesive composition useful for bonding plastic containers and metallized foil. The adhesive composition contains a combination of APAO, a solid benzoate plasticizer, and a hydrocarbon tackifier.

[0018] Sustic, in US Patent No. 5,723,546, discloses a polymer blend consisting of a flexible, predominantly atactic polyolefin polymer with an average molecular weight and an APAO with a low average molecular weight. The combination is said to be useful for hot melt adhesives.

[0019] The combination of APAO with PE, PB or the conventional IPP leads to various drawbacks. Prior art adhesives containing APAO / PE or APAO / PB combinations, such as, for example, those described earlier herein in US Patents 4,120,916, 4,761,450 and 5,478,891, tend to have bad compatibility. These adhesives can undergo phase separation during the application process where the hot melt adhesives have to be held in the molten state at a high temperature for an extended period of time, sometimes for hours or even days. Charring, spalling, and gelling can develop quite rapidly in phase-separated hot melt adhesives, thus causing application equipment to become blocked or clogged. The incompatibility of such polymer blends also confers brittleness, optional haze, little or no open time, and low bond strength. Although conventional APAO and IPP-based hot melts do not have the compatibility issues, they still suffer from all of the other drawbacks described earlier in this document. Furthermore, due to the high crystallinity and high melting point of conventional IPP polymers, hot melt adhesives based on APAO / IPP combinations tend to be hard and brittle, unless the amount of IPP polymer is kept at a very low level. such as, for example, at about or below 2% by weight, as disclosed in prior art US Patent No. 4,022,728. As a result, these adhesives will have poor tensile strength, poor bond strength, and poor impact strength. Another detrimental effect of IPP is the increase in coating temperature. The adhesive must be heated above the melting point of IPP (which ranges from 180 to 200 ° C) to reach a liquid state. The combination of atactic high and low molecular weight polyolefin is an approach that is described in US Patent No. 5,723,546 and, although it offers some improvement in the tensile properties of APAO, it has not yet been able to provide sufficient strength. tensile and high properties

ES 2 388 971 T3 temperature to overcome the deficiencies of hot melts based only on APAO.

[0020] In prior art US Patent No. 5,317,070, Brant et al. disclosed a bonded SPP-based hot melt adhesive having a polymer chain of at least 80% racemic dyads and having a melting point of approximately 100 to 180 ° C. The adhesive is claimed to have good open times between application of the adhesive and formation of the joint. This type of bonded SPP normally lacks flexibility and toughness and therefore will also have poor bond strength and poor impact resistance. Additionally, SPP has an inherent shrinkage problem when it transforms from a liquid to a solid crystalline state. Shrinkage often causes stress build-up at the adhesive / substrate interfaces and consequently catastrophic bond failure.

[0021] Therefore, it would be advantageous to provide a hot melt adhesive that overcomes the drawbacks of prior art adhesives mentioned hereinabove.

[0022] With the advancement in recent years of catalyst technology in the manufacture of polyolefins, especially with recently developed single-site catalyst systems, such as metallocenes, entirely new types of Random Propylene Copolymers (RCP ) of low crystallinity, low melting point and flexible. The technique of single site metallocene catalysts is the subject of numerous publications such as, for example, US Patent Nos. 5,387,568, 5,393,851, 5,416,228, 5,476,914 to Ewen et al. and US Patent No. 5,789,502 to Shamshoun et al. Compared to conventional IPPs, RCP copolymers typically have better flexibility, better impact resistance, lower density, a much lower melting point, and lower crystallinity; These are the characteristics that favor the applications of hot melt adhesives. It was discovered in the present invention that RCP copolymers based on propylene and α-olefins can be advantageously used to overcome the drawbacks of IPP, SPP and APAO in hot melt adhesives to provide well balanced properties of cohesive strength and adhesive strength. Most importantly, the present invention provides a hot melt composition that can be easily processed with a variety of hot melt coating equipment.

[0023] WO01 / 46277, WO01 / 53408, WO9404625, WO0181493, US2002 / 007033 and WO03 / 033612 are additional examples of prior art that disclose an adhesive made from various polymer combinations, with many of the problems highlighted above, which are overcome by the present invention.

Summary of the invention

[0024] The present invention relates to a hot melt adhesive composition comprising a combination of the following components:

(a) 4% to 50% by weight of a random PCR copolymer of propylene and at least one aolefin comonomer having the following molecular structure:

R-CH = CH2 wherein R is hydrogen or a C2 to C10 alkyl group, and said α-olefin comprises 1.5% by weight to 20% by weight of said isotactic random PCR copolymer; wherein said isotactic random PCR copolymer has a density of 0.88 g / cm³ at 0.905 g / cm³ as measured by ASTM Method D-1505, and a melt index between 5 g / 10 min and 200 g / 10 min as measured by ASTM Method D-1238, and a melting point equal to or less than 145 ° C as measured by the DSC method;

(b) 20% to 65% by weight of an adherent;

(c) 15% to 60% by weight of a substantially amorphous atactic poly-α-olefin (APAO) polymer having a degree of crystallinity less than 30% as determined by differential scanning calorimetry (DSC) versus to a highly crystalline polypropylene pattern;

(d) 0% to 40% by weight of a plasticizer;

(e) 0% to 40% by weight of a wax;

(f) 0% to 3% by weight of a stabilizer;

(g) 0% to 60% by weight of a filler; and (h) 2% to 40% by weight of a secondary polymer in addition to said RCP copolymer, said APAO polymer and said adherent; wherein said secondary polymer is selected from the group consisting of: ethylene acrylate, ethylene methacrylate, ethylene methyl acrylate, ethylene methyl methacrylate, an ethylene-styrene interpolymer, an ethylene acrylic acid, ethylene vinyl acetate, ethylene vinyl acetate carbon monoxide, ethylene acrylate carbon monoxide N-butyl, polybutene-1 polymers, high and low density polyethylene, combinations of polyethylene, chemically modified polyethylene, copolymers of ethylene and C1 to C10 mono or di-unsaturated monomers, ethylene / octene copolymers, ethylene / hexane copolymers, ethylene / butene copolymers, polyamides, polybutadiene rubber, polyesters, polyethylene terephthalate, polybutylene terephthalate, thermoplastic polycarbonates, syndiotactic polypropylene, polyacrylocrylamides such as acrylonitrile polymers, and other thermoplastic polypropylene polypropylene acrylocylamides butadiene or styrene, polymethyl pentene, polyphenylene sulfide, aromatic polyurethanes; styrene-acrylonitrile, acrylonitrile-butadiene-styrene rubbers, acrylonitrile-butadiene styrene elastomers; block copolymers AB, ABA, A- (BA) n

ES 2 388 971 T3

B, (AB) nY wherein block A comprises a polyvinyl aromatic block, such as polystyrene, block B comprises a rubber midblock which may be polyisoprene and optionally hydrogenated, such as polybutadiene, Y comprises a multivalent compound and n is an integer of at least 3, polyvinyl alcohols and copolymers thereof, polyvinyl acetate and random copolymers thereof, and polyvinyl aromatic rubber block copolymers; the components make a total of 100% by weight of the composition.

[0025] The hot melt composition is based on a low melting point isotactic polypropylene (RCP) random copolymer, comprising a propylene random copolymer and an α-olefin having the formula RCH = CH2 in which R is hydrogen or a C2 to C10 alkyl group, preferably ethylene. The polymers useful for the present invention will contain at least 1.5% by weight of said α-olefin comonomer, and having a melting point of 145 ° C or less, as measured by the DSC method, an index of melt from 5 to 200 g / 10 min by ASTM Method D-1238, and a solid density of 0.880 to 0.905 g / cc by ASTM Method D-1505.

[0026] The adhesive comprises, in addition to the RCP copolymer, a tackifying resin, an optional plasticizer, APAO, an optional wax and a secondary polymer as the main ingredients. The composition of the present invention takes advantage of the desirable properties of RCP and has overcome the drawbacks of combination adhesives of prior art APAO and bonded SPP. The composition of the present invention provides well balanced tensile strength, toughness, flexibility and adhesion properties. It shows full compatibility, excellent thermal stability, adjustable open time, improved cohesive strength, low dispersity, low shrinkage after solidification, low or no adhesion when solidified, and good processability with conventional coating equipment. In particular, the present invention leads to an adhesive composition that is quite suitable for a variety of spray coating application techniques such as, for example, spiral spray, melt blowing, control coating, control wave and similar, while prior art APAO and SPP based adhesives lack such extensive processability.

[0027] The above advantages are a result of the semi-crystalline structure of the RCP random copolymer. This type of stereochemical structure can be described as having the methyl groups attached to the carbon atoms of successive monomer units on the same side of a hypothetical plane drawn along the main polymer chain with the α-olefin, randomly located at along the chain. Such a structure can be graphically illustrated as follows:

<img file="ES2388971T3_D0004.tif" />

[0028] The addition of an α-olefin, preferably ethylene, in a random pattern reduces the crystallinity of the polymer and thus lowers the melting point as well as slows down the rate of crystallization. As already indicated earlier in this document, the crystallization rate of a polymer is a critical factor that affects the open time of the hot melt adhesive. In contrast to conventional isotactic polypropylene (IPP), which essentially gives no open time due to their rapid crystallization rate, RCPs can be formulated to have workable open times, thereby overcoming the primary impediment of IPPs to hot melt adhesives. The open time of the RCP-based hot melt can be adjusted throughout the formulation to meet the requirements of various bonding applications. As such, an RCP copolymer can be used on its own in a lotion resistant disposable diaper, in desired carton / box applications, or it can be combined with other polymers, such as APAO, for elastic fixation or assembly construction. of hygienic non-woven articles.

[0029] Although any RCP polymer of the type described above can be used in the composition of the present invention, it has been found that a subset of metallocene-catalyzed random copolymers, to be referred to as mRCP, are more useful and therefore , most preferred. Compared to regular PCR polymers, mRCPs offer additional benefits of narrow molecular weight distribution, narrow compositional distribution, and even comonomer distribution along their molecular chain. At the same level of α-olefin comonomer content, mRCPs exhibit lower density, lower melting point, and lower crystallinity than their regular RCP counterparts. These unique characteristics can greatly improve polymer handling during blending, on the one hand, and enhance the performance of hot melt adhesives on the other. RCPm copolymers are especially desirable for hygienic nonwoven applications, where low application temperature is a critical requirement to prevent the substrate from burning or distorting, and where a wide range of application through various non-contact coating techniques is also required. essential. In this sense, RCPm polymers are capable of providing adhesive compositions that have a low softening point and low melt viscosity, thus enabling

ES 2 388 971 T3 a low coating temperature. Furthermore, due to their low density and low crystallinity, mRCP polymers typically exhibit compatibility with other formulation ingredients allowing the use of a wide range of raw materials in various proportions.

[0030] One of the salient characteristics of the hot melt adhesive composition of the present invention is its ability to provide a strong bond to a variety of polar and non-polar substrates, at a very low coating weight. The adhesive works well on both porous and film substrates. At an equal coating weight, the present adhesive will produce a much higher release adhesion value than prior art adhesives. The ability to produce high peel strength at a low coating weight enables the end user to use less adhesive, which is obviously a great cost benefit.

[0031] An object of the present invention is to provide an adhesive that is very little or not adherent at room temperature. This feature is particularly advantageous for use on porous substrates where adhesive penetration and subsequent blocking are of great concern. Blocking is especially disastrous in the manufacture of laminated articles. Rolled items are typically intermittent products that will become final products in a later process. The roll lock makes it difficult, and sometimes almost impossible, to unwind the roll in the subsequent converting process. The non-stick characteristic of the present adhesive in combination with the low coating weight ability will eliminate the blocking problem.

[0032] Another object of the present invention relates to a sprayable hot-melt adhesive for the construction of disposable non-woven articles for joining films of polyethylene, polypropylene, non-woven fabrics and the like to each other and to others. The adhesive provides excellent peel strength and bond durability in such an application.

[0033] Another object of the present invention is to provide a sprayable hot melt for an elastic fixation application in the manufacture of baby diapers, adult incontinence diapers and the like, to bond the elastic strips between a polyethylene film and a non-woven fabric. woven, or between two nonwoven fabrics. This type of adhesive can be formulated to do double duty, both for elastic bonding and for construction.

[0034] Another object of the present invention is to provide a hot melt adhesive that has good bond strength retention when contacted with an emollient, such as mineral oil.

[0035] Another object of the present invention is to provide a hot melt adhesive for sealing cartons and boxes, to provide a strong bond. Due to its toughness and flexibility, the RCP / aPaO-based hot melt is advantageous for low temperature applications. The adhesive of the present invention would offer fiber tear bond at room temperature.

[0036] The hot melt adhesive composition of the present invention comprises as components thereof a mixture of the following ingredients:

to. An isotactic polypropylene random copolymer (RCP) in the amount of 4% to 50% by weight, preferably in the amount of 5% to 40% by weight, and more preferably in the amount of 5% to 25% by weight, said RCP having 80% -98% by weight of propylene and 2% -20% by weight of an α-olefin having the formula R-CH = CH2, in which R is hydrogen or a C2 to C10 alkyl group ; said RCP having a preferred proportion of 94% -97% of propylene and of 3% -6% of α-olefin, the preferred α-olefin being ethylene; said RCP having a density of 0.88 g / cm³ at 0.905 g / cm³ (from 0.88 g / cc to 0.905 g / cc) and a melting index between 5 and 200 g / 10 min and a melting point equal to or less than 145 ° C;

b. A compatible binder in the amount of 20% by weight to 65% by weight, preferably in the amount of 25% by weight to 60% by weight, and most preferably in an amount of 30% to 60% by weight;

c. 5% to 60% by weight, preferably 15% to 40% by weight and most preferably 20% to 40% by weight of atactic poly-α-olefin (APAO), said APAO having a density of 0 , 85 g / cm³ at 0.89 g / cm³(from 0.85 g / cc to 0.89 g / cc) and a glass transition temperature (Tg) of -5 to -40 ° C and a weight average molecular weight (Mw) of 4,000 g / mol to 150,000 g / mol;

d. Optionally, 0% to 40% by weight, preferably about 5% to 30% by weight, and most preferably 10% to 25% by weight of a plasticizer;

and. Optionally, 0% to 3% by weight of a stabilizer or antioxidant; and

F. Optionally, 0% to 40% by weight, preferably 0% to 30% by weight, and most preferably 0% to 20% by weight of a wax; adding the components of the composition up to 100% by weight. The adhesive composition may contain other components, such as a filler and / or a colorant and / or a fluorescent agent and / or a surfactant and / or other polymer that can modify the adhesive properties of the above basic adhesive composition, as described. want. The RCP, APAO, and a compatible binder, along with some or all of the optional ingredients (d) through (f) listed above, will be further combined with one or more secondary polymers. The secondary polymer functions to modify the physical properties and / or specific characteristics of the RCP-based adhesive composition, as desired. For example, the addition of one or more secondary polymers could be used to increase or decrease (i) the elasticity of the

ES 2 388 971 T3 adhesive composition; (ii) adhesion of the adhesive composition; (iii) the low temperature resistance of the adhesive composition; (iv) the high temperature resistance of the adhesive composition; (v) the resistance to permanent deformation of the adhesive composition; (vi) the cohesive strength of the adhesive composition; and / or (vii) the pressure sensitivity characteristics of the adhesive composition. Thus, the adhesive composition further includes:

g. 2% to 40% by weight, preferably 2% to 30% by weight, and more preferably 2% to 20% by weight of a specified secondary polymer from the list described below. As noted above, a single secondary polymer can be incorporated into the adhesive composition to modify a specific property of the adhesive composition, or a combination of secondary polymer can be incorporated to modify several different properties, as desired.

Brief description of the drawings

[0037]

Figure 1a schematically illustrates an undesired poor spiral spray pattern for the adhesive of the present invention;

Figure 1b schematically illustrates a desired perfect spiral spray pattern for the adhesive of the present invention;

Figure 2 illustrates a schematic perspective view of a corrugated cardboard box having the adhesive of the present invention applied to the top flaps thereof; and

Figure 3 illustrates the corrugated cardboard box of Figure 2 sealed by the adhesive of the present invention.

Detailed description of the invention

[0038] According to the present invention, a hot melt adhesive composition is produced, which comprises as the main polymer component an isotactic polypropylene random copolymer (RCP), which comprises a propylene random copolymer and an α-olefin having the formula R-CH = CH2, wherein R is hydrogen or a C2 to C10 alkyl group, preferably ethylene. The RCP is present in the adhesive composition in the amount of about 4% to 50% by weight, preferably in the amount of 5% to 40% by weight, and more preferably in an amount of 5% to 25% by weight. weight. The hot melt adhesive composition of the present invention also includes 20% to 65% by weight, preferably 25% to 60% by weight, and most preferably 30% to 60% by weight of tackifier, 0% to 40% by weight, preferably 5% to 30% by weight and most preferably 10% to 25% by weight of plasticizer, approximately 0% to 40% by weight, preferably 0% to 30% by weight and most preferably 0% to 20% by weight of wax, 0% to 3% by weight stabilizer or antioxidant, 15% to 60% by weight, preferably 15% to 40% by weight, and most preferably 20% to 40% by weight of poly-a- atactic olefin (APAO) and 2% to 40% by weight, preferably 2% to 30% by weight, and most preferably 2% to 20% by weight of a secondary polymer. Optional components such as filler, colorant, blowing agent, fluorescent agent, surfactant, and the like can be added to the basic composition to further modify its properties, as desired.

[0039] The hot melt composition of the present invention includes an RCP copolymer. The technique of making RCP copolymers using Ziegler-Natta catalysts has been disclosed in US Patents 4,330,645 and 5,618,895, and using metallocene catalysts in US Patents 5,476,914 to Ewen et al and 5,789 .502 to Shamshoun et al, the full disclosures of which are hereby incorporated herein by reference. Suitable RCP polymers can be prepared by copolymerizing propylene with another different α-olefin monomer containing 2 to 10 carbon atoms including, but not limited to, ethylene, butene-1, pentene-1, hexane-1,4 methyl pentene-1 and octane-1. Copolymers prepared using the metallocene catalyst are preferred. The most preferred RCO polymers are those RCPm containing ethylene or butene-1 or hexane-1 as the comonomer having a comonomer content ranging from about 2% by weight to about 20% by weight.

The RCP copolymers useful in the present invention preferably have a melting point equal to or less than 145 ° C, more preferably less than 125 ° C, and most preferably less than 120 ° C. RCP copolymers generally have a density in a range of about 0.88 g / cm³ at about 0.905 g / cm³ and preferably 0.88 g / cm³ at 0.89 g / cm³ (0.88 g / cc to 0.89 g / cc) at room temperature as measured by ASTM Test Method D-1505. The polymer also has a melt index (MFR), which is inversely related to the weight average molecular weight Mw, between 5200 g / 10 min and preferably between 7-100 g / 10 min, as measured by the ASTM Test Method D-1238. Examples of copolymers of this type are available under the trade designations EOD01-03, EOD01-04, EOD01-05, EOD01-06 and EOD01-14 from ATOFINA Petrochemicals, Inc., Houston, TX.

[0041] The following Table 1 is a list and comparison of the physical properties of some of the RCPm copolymers useful in the present adhesive composition:

ES 2 388 971 T3

TABLE 1

<td>Shows</td><td>EOD00-14</td><td>EOD01-03</td><td>EOD01-04</td><td>EOD01-05</td><td>EOD01-06</td>

<td></td><td></td><td></td><td></td><td></td><td></td>

<td>Polymer type</td><td>Mrcp</td><td>Mrcp</td><td>Mrcp</td><td>Mrcp</td><td>Mrcp</td>

<td>MFR g / 10 min</td><td> 12,3</td><td> 6,1</td><td> 6,7</td><td> 7,4</td><td> 8,0</td>

<td>X-sol,%</td><td> 0,5, 0,64*</td><td> 1,1, 1,16*</td><td> 1,5, 1,76*</td><td> 2,1, 2,6*</td><td> 4,7, 5,6*</td>

<td>Ethylene by NMR, wt% (mol%)</td><td> 1,5 (2,3)</td><td> 2,3 (3,4)</td><td> 3,2 (4,8)</td><td> 4,7 (7,0)</td><td> 6,5 (9,4)</td>

<td></td><td></td><td></td><td></td><td></td><td></td>

<td>Melting Point ° C (DSC)</td><td> 139,7</td><td> 132,7</td><td> 128,0</td><td> 119,4</td><td> 111,4</td>

<td>GPC</td><td></td><td></td><td></td><td></td><td></td>

<td>Mn x 10³</td><td> 59</td><td> 78</td><td> 81</td><td> 72</td><td> 65</td>

<td>Pm x 10³</td><td> 173</td><td> 234</td><td> 239</td><td> 229</td><td> 212</td>

<td>Pm / Mn</td><td> 2,9</td><td> 3,0</td><td> 3,0</td><td> 3,2</td><td> 3,3</td>

[0042] The APAO component useful in the present invention consists of several different categories of atactic, low molecular weight, low melt viscosity, and substantially amorphous propylene-based polymers. The term "substantially amorphous" is defined herein as having a degree of crystallinity of less than 30% as determined by differential scanning calorimetry (DSC) against a highly crystalline polypropylene standard. These polymers can be homopolymers of propylene or copolymers of propylene with one or more α-olefin comonomers such as, for example, ethylene, butene-1, hexane-1 and octene-

1. The weight average molecular weight of APAO polymers within the scope of the present invention is in the range of about 4,000 to about 150,000 g / mole, preferably about 10,000 to about 100,000 g / mole. Such polymers advantageously have a softening point between about 80 and 170 ° C and a glass transition temperature of about -5 to -40 ° C. Although any APAo polymer that is in the range of physical properties herein described above can be used, the most preferred APAO is selected from the group consisting of propylene homopolymer, propylene-ethylene copolymer, propylene-butene-1 copolymer, and propylene-ethylene-butene-1 terpolymer. APAO polymers of the types described above are commercially available from Eastman Chemical Company, Kingsport, TN, under the trade name Eastoflex, from Huntsman Corporation, Houston, TX, under the trade name Rextac or from Degussa Corporation, Passipanny, NJ, under the trade name Vestoplast. As indicated, 15% to 60% by weight of APAO can be combined in the adhesive composition, preferably 15% to 40% by weight, and most preferably 20% to 40% by weight.

[0043] Tackifier or tackifying resins used in the hot melt adhesives of the present invention are those that enhance adhesive properties and improve specific adhesion. As used herein, the term "tackifying resin" includes:

(a) Aliphatic and cycloaliphatic petroleum hydrocarbon resins having Ring and Ball softening points of 10 ° C to 160 ° C, as determined by ASTM method E28-58T, resulting in the latest resins from the polymerization of monomers consisting primarily of aliphatic and / or cycloaliphatic olefins and diolefins; Also included are hydrogenated aliphatic and cycloaliphatic petroleum hydrocarbon resins; examples of such commercially available resins based on such a C5 olefin fraction are the tackifying resin Piccotac 95 sold by Eastman Chemical Company, and Escoreze 1310LC sold by ExxonMobil Chemical Company;

(b) Aromatic petroleum hydrocarbon resins and hydrogenated derivatives thereof;

(c) Aliphatic / aromatic petroleum derived hydrocarbon resins and hydrogenated or acid functionalized derivatives thereof;

(d) Aromatically modified cycloaliphatic resins and hydrogenated derivatives thereof;

(e) Polyterpene resins having a softening point of 10 ° C to 140 ° C, the latter generally being the result of the polymerization of terpene hydrocarbons, such as monoterpene known as pinene, in the presence of Friedel catalysts. Crafts, at moderately low temperatures; hydrogenated polyterpene resins are also included;

(f) Copolymers and terpolymers of natural terpenes, for example styrene / terpene, α-methyl styrene / terpene and vinyl toluene / terpene;

(g) natural and modified rosin such as, for example, rosin gum, wood rosin, tallow oil rosin, distilled rosin, hydrogenated rosin, dimerized rosin and polymerized rosin;

(h) Glycerol and pentaerythritol esters of natural and modified rosin such as, for example, pale wood rosin glycerol ester, hydrogenated rosin glycerol ester, polymerized rosin glycerol ester, pentaerythritol ester of pale wood rosin, hydrogenated rosin pentaerythritol ester, tallow oil rosin pentaerythritol ester, and modified pentaerythritol ester with

ES 2 388 971 T3 rosin phenolic;

(i) phenolic modified terpene resins such as, for example, the resin product resulting from the condensation in an acidic medium of a terpene and a phenol;

[0044] Mixtures of two or more of the tackifying resins described above may be required for some formulations. Although a range of 20% to 65% by weight of tackifying resin can be used, the preferred amount is 25% to 60% by weight and the most preferred amounts range from 30% to 60% by weight. Tackifying resins that are useful for the present invention may perhaps include polar tackifying resins, however the choice of available polar tackifying resins is limited in view of the fact that many of the polar resins appear only partially compatible with RCPm copolymers of metallocene catalyzed polypropylene and APAO polymers.

[0045] As indicated above, tackifying resins that are useful within the scope of the present invention comprise from 20% to 65% by weight. Preferably, the tackifying resins can be selected from any of the non-polar types, which are commercially available. Preferred resins are aliphatic petroleum hydrocarbon resins examples of which are based on C5 olefins such as Piccotac 9095 (formerly Hercotac 1148) available from Eastman Chemical Company, Kingsport, TN. Most preferred are non-polar products based on hydrogenated DCPD or aromatically modified derivatives thereof, with softening points above 70 ° C. Examples of such resins are Escoreze 5400 and Escoreze 5600, available from ExxonMobil Chemical Company.

[0046] A plasticizer may be present in the composition of the present invention in amounts of 0% to 40% by weight, preferably 5% to 30%, and more preferably 10% to 25% by weight, to provide control. desired viscosity and confer flexibility. A suitable plasticizer can be selected from the group that includes normal plasticizing oils, such as mineral oil, but also olefin oligomers and low molecular weight polymers, as well as vegetable and animal oils and derivatives of such oils. The petroleum-derived oils that can be used are relatively high-boiling materials containing only a minor proportion of aromatic hydrocarbons. In this regard, the aromatic hydrocarbons should preferably be less than 30% and more particularly less than 15% of the oil, as measured by the aromatic carbon atom fraction. More preferably, the oil can be essentially non-aromatic. The oligomers can be polypropylenes, polybutenes, hydrogenated polyisoprenes, hydrogenated polybutadienes, or the like having an average molecular weight between about 350 and about 10,000. Suitable vegetable and animal oils include glycerol esters of normal fatty acids and the polymerization products thereof. Other useful plasticizers can be found in the conventional dibenzoate, phosphate, phthalate ester families, as well as mono- or polyglycol esters. Examples of such plasticizers include, but are not limited to, dipropylene glycol benzoate, pentaerythritol tetrabenzoate, 2-ethylhexyl diphenyl phosphate, polyethylene glycol 400-di-2-ethylhexoate; butyl benzyl phthalate, dibutyl phthalate, and dioctylphthalate. The plasticizers that find utility in the present invention can be any number of different plasticizers, although the inventors have found that mineral oil and liquid polybutenes having a molecular weight of less than 5,000 are particularly advantageous. As will be appreciated, plasticizers have typically been used to reduce the viscosity of the overall adhesive composition without substantially lowering the adhesive strength and / or service temperature of the adhesive as well as to extend the open time and improve the flexibility of the adhesive.

[0047] Waxes can be used to reduce the melt viscosity of the hot melt adhesive composition. Although varying amounts of 0% to 40% by weight can be used in the composition of the present invention, preferred amounts are between 0% and 30% by weight and more preferably between 0% and 20% by weight. . These waxes can also affect the setting time and softening point of the adhesive. Useful waxes include:

1. a low molecular weight, that is, a number average molecular weight (Mn) equal to 500-6000, polyethylene having a hardness value as determined by ASTM method D-1321 of about 0.1 to 120, having an ASTM softening point of about 65 ° C to 140 ° C;

2. Petroleum waxes, such as paraffin wax, having a melting point of approximately 50 ° C to 80 ° C and microcrystalline wax having a melting point of approximately 55 ° C to 100 ° C, the latter melting points being determined by ASTM method D127-60;

3. synthetic waxes made by polymerization of carbon monoxide and hydrogen, such as Fischer-Tropsch wax; and

Four. polyolefin waxes. As used herein the term "polyoefin wax" refers to those polymeric or long chain entities comprised of olefin monomer units. These types of materials are commercially available from Eastman Chemical Co. under the trade name Epolene. Preferred materials for use in the composition of the present invention have a Ring and Ball softening point of from about 100 ° C to 170 ° C. As should be understood, each of these wax diluents is solid at room temperature.

[0048] Other substances including hydrogenated fish and vegetable animal fats and oils, such as

ES 2 388 971 T3 tallow, lard, soybean oil, cottonseed oil, castor oil, menhaden oil, cod liver oil and the like, and which are solid at room temperature thanks to the fact that they are hydrogenated, They have also been found to be useful with respect to their performance as an equivalent of the wax diluent. These hydrogenated materials are often referred to in the adhesive industry as animal or vegetable waxes.

[0049] The present invention may include a stabilizer in an amount of 0% to 3% by weight. Preferably 0.1% to 1% of a stabilizer is incorporated into the composition. Stabilizers that are useful in the hot melt adhesive compositions of the present invention are incorporated to help protect the polymers listed above, and thus the entire adhesive system, from the defects of thermal and oxidative degradation that normally occurs during the manufacture and application of the adhesive as well as in the ordinary exposure of the final product to the ambient environment. Among the applicable stabilizers are high molecular weight hindered phenols and multifunctional phenols, such as sulfur and phosphorous containing phenols. Hindered phenols are well known to those skilled in the art and can be characterized as phenolic compounds that also contain sterically bulky radicals in close proximity to the phenolic hydroxyl group thereof. In particular, tertiary butyl groups are generally substituted on the benzene ring in at least one of the ortho positions to the phenolic hydroxyl group. The presence of these bulky sterically substituted radicals in the vicinity of the hydroxyl group serves to retard its stretching frequency and, consequently, its reactivity: this steric hindrance therefore provides the phenolic compound with its stabilizing properties. Representative hindered phenols include:

1,3,5-trimethyl-2,4,6-tris (3-5-di-tert-butyl-4-hydroxybenzyl) benzene; pentaerythritol tetrakis-3 (3,5-di-tert-butyl-4-hydroxyphenyl) propionate; n-octadecyl-3 (3,5-di-tert-butyl-4-hydroxyphenyl) propionate;

4,4'-methylenebis (4-methyl-6-tert-butylphenol);

2,6- di-tert-butylphenol;

6- (4-hydroxyphenoxy) -2,4-bis (n-octylthio) -1,3,5-triazine;

2.3.6- tris (4-hydroxy-3,5-di-tert-butyl-phenoxy) -1,3,5-triazine; di-n-octadecyl-3,5-di-tert-butyl-4-hydroxybenzylphosphonate;

2- (n-octylthio) ethyl-3,5-di-tert-butyl-4-hydroxybenzoate; and sorbitol hexa-3 (3,5-di-tert-butyl-4-hydroxyphenyl) propionate.

[0050] Pentaerythritol tetrakis-3 (3,5-di-tert-butyl-4-hydroxyphenol) propionate is especially preferred as a stabilizer.

[0051] The performance of these stabilizers can be further enhanced by using, in conjunction with them;

(1) synergists such as, for example, phosphite thiodipropionate esters; and (2) chelating agents and metal deactivators such as, for example, ethylenediaminetetraacetic acid, salts thereof, and disalicylalpropylene diimine.

The secondary polymer is present in the composition of the present invention in amounts of 2% to 40% by weight, preferably 2% to 30% by weight, and more preferably 2% to 20% by weight. Any individual secondary polymer can be used, or mixtures of two or more secondary polymers can be incorporated into the adhesive composition, depending on the desired formulation.

[0053] Said secondary polymer h) is selected from the group consisting of: ethylene acrylate, ethylene methacrylate, methyl ethylene acrylate, methyl ethylene methacrylate, an ethylene-styrene interpolymer, an ethylene acrylic acid, ethylene vinyl acetate, ethylene vinyl acetate carbon monoxide, ethylene N acrylate carbon monoxide -butyl, polybutene-1 polymers, high and low density polyethylene, combinations of polyethylene, chemically modified polyethylene, ethylene copolymers and C1 to C10 mono- or diunsaturated monomers, ethylene / octene copolymers, ethylene / hexane copolymers, ethylene / butene copolymers, polyamides, polybutadiene rubber, polyesters, polyethylene terephthalate, polybutylene terephthalate, thermoplastic polycarbonates, syndiotactic polypropylenes such as acrylonitrile polypropylene, polyacrylamides such as acrylonitrile polypropylenes, and other thermoplastic polypropylene copolymers or styrene, polymethylpentene, polyphenylene sulfide, aromatic polyurethanes; styrene-acrylonitrile, acrylonitrile-butadiene-styrene, styrene-butadiene rubbers, acrylonitrile-butadiene-styrene elastomers; AB, ABA, A- (BA) nB, (AB) nY block copolymers in which block A comprises an aromatic polyvinyl block, such as polystyrene, block B comprises a rubber midblock which may be polyisoprene and optionally hydrogenated, such as polybutadiene, Y comprises a multivalent compound and n is an integer of at least 3, polyvinyl alcohols and copolymers thereof, polyvinyl acetate and random copolymers thereof and polyvinyl aromatic-rubber block copolymers;

Examples of the latter block copolymers include styrene-butadiene, styrene-butadiene-styrene, styrene-isoprene-styrene, styrene-ethylene-butylene-styrene, and styrene-ethylene-propylene-styrene.

[0055] Although the total styrene content of the polymers can be as high as 51% by weight of the polymer, and since the polymers can have more than two A blocks for optimal performance, the total A block

ES 2 388 971 T3 should preferably be less than or equal to about 45% by weight of the polymers and, more preferably, it is less than or equal to 35% by weight of the polymer. In an SBS (styrene-butadienestyrene) copolymer, the preferred molecular weight is about 50,000 to 120,000, and the preferred styrene content is about 20 to 45% by weight. In a SIS (styrene-isoprene-styrene) copolymer, the preferred molecular weight is about 100,000 to 200,000, and the preferred styrene content is about 14-35% by weight. Hydrogenation of the butadiene midblocks produces rubber midblocks that are typically converted to ethylene-butylene midblocks.

Such block copolymers are available from Kraton Polymers, Enichem, Fina, and Dexco. Tapered block or multiblock copolymers (type A- (BA) nB) are available from Firestone.

[0057] Other secondary polymers that could be used are syndiotactic polypropylene (SPP) polymers. SPP polymers are essentially high molecular weight, stereospecific propylene homopolymers or copolymers of propylene with other α-olefin monomers such as ethylene, butene-1, or hexene-1. APAO polymers are a family of amorphous low molecular weight homopolymers of propylene or copolymers of propylene with ethylene or butene or hexene, as previously described herein.

The secondary polymer functions to modify the functions of the specific polymer to modify the specific physical properties and / or characteristics of the PCR-based adhesive composition, as desired. For example, the addition of one or more secondary polymers could be used to increase or decrease (i) the elasticity of the adhesive composition; (ii) adhesion of the adhesive composition; (iii) the low temperature resistance of the adhesive composition; (iv) the high temperature resistance of the adhesive composition; (v) the resistance to permanent deformation of the adhesive composition; (vi) the cohesive strength of the adhesive composition; and / or (vii) the pressure sensitivity characteristics of the adhesive composition. The relative change (increase or decrease) of the above characteristics is measured relative to the adhesive composition without the addition of the secondary polymer. Thus, for example Kraton G1652 or Kraton G1657, both of which are styrene / ethylene-butylene / styrene block copolymers (SEBS), can be added to provide increased elongation characteristics to the RCP polymer to increase the elasticity of the composition. of adhesive. The increased elasticity results in better sprayability characteristics for the adhesive composition. In another example, Eastoflex 1003 or Eastoflex 1060, both ethylene-based APAOs, can be added to provide increased addition characteristics for the composition, if desired.

[0059] As used herein, the term elasticity is the ability of a material to regain its original shape partially or completely after the deformation force has been removed.

As used herein, the term "adhesion" means the state in which two surfaces are held together by interfacial forces, which can be a combination of valence forces or the interlocking action or both.

[0061] As used herein, the term "low temperature resistance" means the relative ability of an adhesive to retain its bond strength and structural integrity at relatively low temperatures (ie, below room temperature).

As used herein, the term "high temperature resistance" means the relative ability of an adhesive to retain its bond strength and structural integrity at elevated temperatures (eg, at body temperature or under storage conditions).

[0063] As used herein, the term "permanent set resistance" means the ability of an adhesive to hold its elastic strips stretched in place, without significant slippage. Additional definition can be found in Examples 1-4 contained herein.

[0064] As used herein, the term "cohesive strength" means the degree of internal strength of a material to resist deformation. There are several ways to determine cohesive strength, such as the tensile test method using an Instron type tensile tester.

[0065] As used herein, the term pressure sensitivity means the ability of an adhesive to form a bond to a substrate using only pressure.

[0066] It should be understood that other optional additives may be incorporated into the adhesive composition of the present invention to further modify the particular physical properties. These can include, for example, materials such as inert colorants (for example titanium dioxide), fluorescent agents, 0% to 60% by weight of fillers, surfactants and / or blowing agents. Typical fillers include talc, calcium carbonate, clay, silica, mica, wollastonite, feldspar, aluminum silicate, alumina, hydrated alumina, glass microspheres, ceramic microspheres, thermoplastic microspheres, barite, and wood flour. Surfactants are particularly important in adhesives for use on hygienic disposable nonwovens because they can reduce

ES 2 388 971 T3 drastically the surface tension, for example, of the adhesive applied to the core of the diaper, thus allowing faster transport and subsequent absorption of urine by the core.

[0067] A surfactant may be present in the composition of the present invention in amounts of from about 0.1% to about 30% by weight, and preferably from about 1% to about 10% to make the adhesive more hydrophilic. The surfactant preferably has a hydrophilic-lipophilic balance (HLB) number of less than 15. The HLB of a surfactant is an expression of its hydrophilicolipophilic balance, that is, the balance of the size and strength of the hydrophilic (water attracted or polar groups) and lipophilic (oil attracted or nonpolar groups) groups of the surfactant. All surfactants consist of a molecule that combines both hydrophilic and lipophilic groups.

[0068] The surfactant must be reasonably compatible with the other raw materials used in the hot melt adhesive so that it does not adversely affect the performance of the adhesive. On the other hand, the surfactant must be an efflorescence to the surface of the adhesive, to make the adhesive more hydrophilic. In this way, a delicate balance of compatibility must be maintained. The surfactant also should not contain any water or other solvents that make it processable in hot melt mixing equipment and non-toxic to the end user. The surfactant also should not be sufficiently stable and non-volatile to allow processing in hot melt fabrication and application equipment with no effect on the adhesive.

[0069] As used herein the term surfactant or surface active agent refers to any compound that reduces surface tension when dissolved in water or aqueous solutions, or that reduces the interfacial tension between two liquids, or between a liquid and a solid. Examples of suitable surfactants include, but are not limited to, the following:

(1) Fatty acid esters such as glycerol esters, PEG esters and sorbitan esters, including ethylene glycol distearate, ethylene glycol monostearate, glycerol mono- and / or dioleate, PEG dioleate, PEG monolaurate, sorbitan monolaurate , sorbitan trioleate, etc. These surfactants are available from ICI, Thone-Poulenc, and other sources.

(2) Nonionic ethoxylates such as alkylphenol ethoxylates, alcohol ethoxylates, alkylamine ethoxylates, etc., including octylphenol ethoxylate, nonylphenol ethoxylate, alkylamine ethoxylates, etc. These surfactants are available from Rhone-Poulenc, Union Carbide, and other sources.

(3) Nonionic surfactants such as 2,4,7,9-tetramethyl-5-decine-4,7-diol available from Air Products.

(4) Ethylene oxide / propylene oxide copolymers which are available from Union Carbide, BASF, etc. It should be noted that these and other surfactants can be mixed if necessary to produce the best combination of hydrophilic performance properties.

[0070] Atmer 688, a combination of nonionic surfactant and Alkamuls GMS / C, a glycerol monostearate, both manufactured by ICI Americas, Inc. have been found to be the preferred surfactants for use in the present adhesive composition.

[0071] The hot melt adhesive composition of the present invention can be formulated using any of the mixing techniques known in the art. A representative example of the prior art mixing procedure involves placing all components, except polymer RCP, in a jacketed mixing vessel equipped with a rotor, and subsequently raising the temperature of the mixture to a range of 160 ° C to 200 ° C. ° C to melt the contents. It should be understood that the precise temperature to be used in this step will depend on the melting points of the particular ingredients. The rCp copolymer and / or other polymers (eg APAO) are subsequently introduced into the vessel with stirring and mixing is allowed to continue until a consistent and uniform mixture is formed. The contents of the container are protected with inert gas, such as carbon dioxide or nitrogen throughout the mixing process.

The resulting hot melt adhesives can then be applied to substrates using a variety of application techniques. Examples include hot melt glue gun, hot melt slotted die coating, hot melt wheel coating, hot melt roll coating, melt blow coating, spiral spray coating, and the like. In a preferred embodiment, the hot melt adhesive is sprayed onto a substrate using spiral spraying, which is a preferred technique for producing a filamentous spiral pattern for elastic fixation and construction in the manufacture of a diaper. In one example, a meltblown coater is equipped with a disc as a coating die having a nozzle tip in the center. The tip is surrounded by a series of angled holes for hot air jets to pass through. The hot melt adhesive is pumped out of the nozzle in the form of a fine filament. The filament is then rotated by high speed hot air jets emerging from the holes, thereby producing a helical pattern from a single strip of adhesive. It is not the intention of this invention to provide a complete description of spraying techniques and details can be found in the literature.

[0073] The adhesive composition of the present invention can be used in a number of applications such as, for example, in disposable nonwoven hygienic articles, paper converting, flexible packaging, machining

ES 2 388 971 T3 for wood, carton and box sealing, labeling and other assembly applications. Particularly preferred applications include disposable diapers and feminine sanitary napkin construction, elastic fastening for adult incontinence diapers and diapers, diaper and napkin core stabilization, diaper backsheet lamination, industrial filter material conversion, surgical gowns and assembly of surgical drapes, etc.

Tests and materials

[0074] Brookfield viscosity was tested according to ASTM Method D-3236 at 163 ° C (325 ° F).

[0075] Ring and Ball softening point was determined with an automated Herzog unit according to ASTM method E-28.

[0076] Peel strength was measured in a 180 ° geometry with a tensile tester (Instron Model 55R1122) in a controlled atmosphere environment (20 ° C and 50% relative humidity). Before testing, the samples were conditioned in the controlled environment for approximately 12 hours to ensure reproducibility and precision of the data. The test was carried out at a crosshead speed of 0.3 m / min (12 / min). The average peel value of six replicas, normalized to the unit g / cm (g / in.), Was presented as the peel strength.

[0077] The test for resistance to permanent deformation was carried out with the rolled test specimens of the Examples herein described later. The test specimen, cut to approximately 300mm in length, was fully stretched and its ends securely attached to a piece of rigid corrugated cardboard. A length of 300mm was marked and the elastic strips were cut at the marks. The test sample was then placed in a circulating air oven at 37.8 ° C (100 ° F). Under these conditions, the elastic strips that are stretched can be retracted a certain distance. The distance between the extremes was measured after four hours. The ratio of the final length to the initial length, defined as permanent set retention and expressed as a percentage (%) is a measure of the ability of the adhesive to contain the elastic strips.

Spreadability was measured empirically on a Meltex CT225 hot melt coater (Nordson). Coating conditions varied depending on the adhesive sample.

[0079] EOD01-06 is a propylene-ethylene RCPm type copolymer prepared using a single site metallocene catalyst system such as that disclosed in US Patent 5,476,914. The copolymer contains approximately 6% by weight of ethylene and is commercially available from AtoFina Petrochemicals, Inc., Houston, TX. It has a density of 0.89 g / cm³ (0.89 g / cc) and a DSC melting point of 111.4 ° C, and has a melt index of approximately 8 g / 10 min. as determined using ASTM Method D-1238.

[0080] END00-14 is a propylene-ethylene RCPm type copolymer prepared using a single site metallocene catalyst system such as that disclosed in US Patent 5,476,914. The copolymer contains approximately 2% ethylene by weight and is commercially available from AtoFina Petrochemicals, Inc., Houston, TX. It has a density of 0.90 g / cm³ and a DSC melting point of 139.7 ° C, and has a melting index of approximately 14 g / 10 min. as determined using ASTM Method D-1238.

[0081] EOD02-07, obtained from AtoFina Petrochemicals, is a propylene-ethylene RCPm copolymer having approximately 6% by weight of ethylene. It has a melting point of approximately 112 ° C, a density of 0.89 g / cm³ (0.89 g / cc) and a melt flow rate of approximately 50 g / 10 min.

[0082] EOO02-08, obtained from AtoFina Petrochemicals, is a propylene-ethylene RCPm copolymer having approximately 6% by weight of ethylene. It has a melting point of approximately 112 ° C, a density of 0.89 g / cm³ (0.89 g / cc) and a melt index of approximately 100 g / 10 min.

[0083] Rextac RT2330, available from Huntsman Corporation, is an APAO-type atactic propylene-ethylene copolymer having a Brookfield viscosity of approximately 3,000 mPa.s (3,000 cP) at 190 ° C, a Tg of approximately -29 ° C and a softening point of about 141 ° C.

[0084] Eastoflex P1010, obtained from Eastman Chemical Company, Kingsport, TN, is an atactic APAO homopolypropylene having a Brookfield viscosity of about 1,000 mPa.s (1,000 cP) at 190 ° C, a Tg of about -10 ° C. and a softening point of about 150 ° C.

[0085] Eastoflex D-178, also obtained from Eastman Chemical Company, is an APAO type atactic propylene-ethylene copolymer having a Brookfield viscosity of about 3,000 mPa.s (3,000 cP) at 190 ° C, a Tg of -27 ° C and a softening point of approximately 130 ° C.

[0086] Eastoflex E-1200, also obtained from Eastman Chemical Company, is an APAO-type atactic propylene-ethylene copolymer having a Brookfield viscosity of approximately 12,000 mPa.s (12,000 cP) at 190 ° C,

ES 2 388 971 T3 has a Tg of about -28 ° C and a softening point of about 135 ° C.

[0087] Escorez 5380, available from ExxonMobil Chemical Company, Houston, TX, is a very light colored hydrogenated cycloaliphatic hydrocarbon binder having an R and B softening point of approximately 80 ° C.

Hercotac 1148 is a C5 aliphatic hydrocarbon resin having a Ring and Ball softening point of 100 ° C. It is available from Eastman Chemical Company.

Nyplast 222B is a mineral oil plasticizer purchased from Nynas Canada, Inc., Mississauga, Ontario, Canada.

[0090] Wingtack 10 is a liquid aliphatic C5 hydrocarbon resin having a Brookfield viscosity of approximately 20,000-40,000 mPa.s (20,000-40,000 cP) at 25 ° C and a Ring and Ball softening point of approximately 10 ° C. It is available from Goodyear Chemicals, Akron, OH.

[0091] Marcus 300, available from Marcus Oil &amp; Chemicals, Inc., is a synthetic polyethylene wax having a melting point of approximately 116 ° C (240 ° F).

Irganox 1010 is an antioxidant-type hindered phenol obtained from Ciba-Specialty Chemicals, Tarryton, NY.

[0093] Uvitex OB, also obtained from Ciba Specialty Chemicals, is a fluorescent agent.

Lycra 740 is an elastic strip having a basis weight of 740 denier. It is available from DuPont.

[0095] Control A is a styrene-isoprene-styrene block copolymer (SIS) based on a hot melt adhesive having a Brookfield viscosity of 5600 mPa.s at 177 ° C (5600 cP at 350 ° F) and a point of Ring and Ball softening of approximately 104 ° C (220 ° F). It is available from Bostik Findley, Inc., Wauwatosa, WI.

SMS is a melt-blown melt-spun nonwoven composition obtained from Kimberly-Clark Corporation, Neenah, WI.

[0097] The invention is further illustrated by the examples set forth below.

Reference Examples 1-4

[0098] Hot melt adhesive examples 1-4 shown in Table 2 were prepared with the ingredients and mixing procedures described earlier herein. A total of 2000 grams each was prepared and mixing was performed at 177-191 ° C (350 - 375 ° F) in a carbon dioxide atmosphere in a laboratory-type mixer consisting of a motor driven propellant, a jacket heater, a temperature control unit, and a container that is approximately 1 gallon (3.8 liters) in size. Appropriate amounts of each component, calculated according to the proportions shown in the table, except for the mRCP copolymer were added to the container. The temperature of the container was then raised to melt the contents. After the ingredients in the container were completely melted, the motor was started to initiate stirring. Subsequently, the mRCP copolymer component was introduced and thoroughly mixed therein. Adhesive Examples 1-4 are especially useful as a spring-set adhesive for spring-set applications.

[0099] The Brookfield Viscosity, Ring and Ball Softening Point and Permanent Set Retention tests were performed in Examples 1-4 according to the procedures of this document described above. Adhesion at room temperature was judged by the adhesiveness of the adhesive to human fingers. The test specimens for the Set Retention Test were formed using a spiral spray technique on a Meltex CT225 hot melt coater that was equipped with a 0.46 mm (0.018) spiral spray nozzle. To prepare the test sample, three elastic strips (Lycra 740), which were stretched at 300% elongation, were laminated between a 25.4 µm (1.0 mils) thick layer of polyethylene film, and one layer of spun polypropylene nonwoven fabric, or between two identical SMS nonwoven fabrics. The sprayability was evaluated during the coating process by observing the shape of the spiral pattern. The sprayability was judged acceptable if a good spiral pattern as depicted in Figure 1b was observed; otherwise it was judged unacceptable (Figure 1a): The adhesives were sprayed in a spiral with a coating weight of 12 g / m² with an open time of 0.25 seconds and a compression at 1 bar in the pressure rollers and the application temperature was set at 163 ° C (325 ° F). The adhesives of Examples 1-4 were found to have almost no room temperature adhesion, low melt viscosity, good spreadability, and good set retention properties.

ES 2 388 971 T3

TABLE 2

<td colspan="5">REFERENCE EXAMPLES 1 - 4 (ELASTIC FASTENING)</td>

<td></td><td>EX 1 (% p.)</td><td>EX 2 (% p.)</td><td>EX 3 (% p.)</td><td>EX 4 (% p.)</td>

<td>EOD01-06</td><td> 8,0</td><td> 8,0</td><td> 10,0</td><td> —</td>

<td>EOD02-07</td><td> —</td><td> —</td><td> —</td><td> 10,0</td>

<td>Eastoflex P1010</td><td> 30,0</td><td> 35,5</td><td> —</td><td> —</td>

<td>Eastoflex D178</td><td> —</td><td> —</td><td> —</td><td> 20,0</td>

<td>Rexflex RT 2330</td><td> —</td><td> —</td><td> 30,0</td><td></td>

<td>Wingtack 10</td><td> 10,0</td><td> —</td><td> —</td><td> —</td>

<td>Hercotac 1148</td><td> 46,5</td><td> 46,0</td><td> 47,0</td><td> 59,5</td>

<td>Nyplast 222B</td><td> 5,0</td><td> 10,0</td><td> 12,5</td><td> 10,0</td>

<td>Irganox 1010</td><td> 0,5</td><td> 0,5</td><td> 0,5</td><td> 0,5</td>

<td></td><td></td><td></td><td></td><td></td>

<td>Viscosity mPa.s (cP), 163 ° C (325 ° F)</td><td> 2880</td><td> 3090</td><td> 6250</td><td> 2090</td>

<td>Softening Point (° F) (° C)</td><td> 275 (135)</td><td> 282 (139)</td><td> 249 (120,6)</td><td> 240 (115,6)</td>

<td>'Retention of permanent deformation (%)</td><td></td><td></td><td></td><td></td>

<td>Poly / Lycra / NW</td><td> 94</td><td> 96</td><td> 91</td><td> 83</td>

<td>SMS / SMS</td><td> 87</td><td> 94</td><td> 85</td><td> 71</td>

Reference Examples 5-7

[0100] Reference Examples 5-7 were formulated using the same procedure as described herein above with the ingredients shown in Table 3. These formulations are particularly suitable as laminating adhesives for a variety of flexible packaging applications and as construction adhesives for disposable nonwoven applications. When used as such, peel strength is the most important measure of adhesive performance. The peel strength of Examples 5-7 was measured and the results are also presented in Table 3. Test samples for peel strength measurement were prepared by laminating the same polyethylene film and polypropylene spunbonded fabric as in Examples 1-4 with a spiral spray coating technique on a CT225 hot melt coater equipped with three ITW controlled fiberizing nozzles. The adhesive was applied in the amount of 4 g / m² at an application temperature of 149 ° C (300 ° F) and an open time of 0.5 seconds. The adhesives of Examples 5-7 were found to have little or no low room temperature adhesion, low melt viscosity, good spreadability, and good film / nonwoven bonding.

TABLE 3

<td colspan="4">Reference EXAMPLES 5 - 7 (CONSTRUCTION)</td>

<td></td><td>EX 5 (% p.)</td><td>EX 6 (% p.)</td><td>EX 7 (% p.)</td>

<td>EOD01-06</td><td> 10,0</td><td> —</td><td> —</td>

<td>EOD02-08</td><td> —</td><td> 15,0</td><td> 10,0</td>

<td>Eastoflex-1200</td><td> 6,0</td><td> —</td><td> 20,0</td>

<td>Eastoflex D178</td><td> 9,0</td><td> 30,0</td><td> 10,0</td>

<td>Hercotac 1148</td><td> 44,5</td><td> 34,5</td><td> 39,5</td>

<td>Nyplast 222B</td><td> 30,0</td><td> 20,0</td><td> 20,0</td>

<td>Irganox 1010</td><td> 0,5</td><td> 0,5</td><td> 0,5</td>

<td></td><td></td><td></td><td></td>

<td>Viscosity mPa.s (cP), 163 ° C (325 ° F)</td><td> 3750</td><td> 3490</td><td> 3180</td>

<td>Softening Point ° C (° F)</td><td> 103 (218)</td><td> 113 (235)</td><td> 114 (237)</td>

<td>Coating T ° C (° F)</td><td> 149 (300)</td><td> 149 (300)</td><td> 149 (300)</td>

<td>¹Peel strength (g)</td><td> 432</td><td> 371</td><td> 373</td>

Reference Examples 8-9

[0101] The hot melt adhesives of Examples 8-9 were prepared using the same procedure as

ES 2 388 971 T3 described in this document above with the ingredients shown in Table 4. In examples 8 and 9 the adhesive contains a wax (Marcus 300) that replaces the APAO ingredient in the previous formulations illustrated in this document. Thus, the adhesives of Examples 8 and 9 do not contain APAO. A total of 250 grams each was prepared and mixing was done at 177 ° C (350 ° F) in a CO2 atmosphere. They are particularly useful for carton and box sealing applications. To illustrate the use of such an application, reference is made to Figures 2 and 3 herein, where single adhesive beads of approximately 2mm in diameter, illustrated as 21a and 21b in Figure 2, are applied by hand through from the upper surface of the upper flaps 22a and 22b of a corrugated cardboard box 20 as shown in the figure. Immediately after application of the adhesive, the upper flaps 22a and 22b of the box 20 are folded over and brought into contact with the lower flaps 23a and 23b to seal the box 20. The flaps 22a, 22b, 23a and 23b remain then press together for approximately 2 minutes to seal box 20 as shown in Figure 3. The adhesive produced a fiber tear bond in approximately 20 minutes after application of the adhesive.

TABLE 4

<td colspan="3">REFERENCE EXAMPLES 8 - 9</td>

<td></td><td>EX 8</td><td>EX 9</td>

<td>EOD00-14</td><td> 15,0</td><td> —</td>

<td>EOD02-08</td><td> —</td><td> 30,0</td>

<td>Marcus 300</td><td> 18,0</td><td> 5,0</td>

<td>Escorez 5380</td><td> 56,0</td><td> 49,0</td>

<td>Nyplast 222B</td><td> 10,0</td><td> 15,0</td>

<td>Irganox 1010</td><td> 1,0</td><td> 1,0</td>

<td>Viscosity at 163 ° C (325 ° F) mPa.s (CP)</td><td> 3550</td><td> 7150</td>

<td>Softening Point ° C (° F)</td><td> 123(253)</td><td> 107(225)</td>

Reference Examples 10-11

[0102] Examples 10-11 were formulated using the same procedure as described previously herein with the ingredients listed in Table 5. These formulations are particularly suitable as lotion resistant adhesives for disposable nonwoven applications.

[0103] Manufacturers of feminine hygiene tampons, diapers, and other absorbent articles may from time to time apply an emollient coating to the skin-contacting surface of the topsheet of a disposable diaper or an emollient coating over the skin-contacting surface of the topsheet of a feminine hygiene tampon. This emollient is intended to help prevent skin rashes that can develop while using such items. Petrolatum is particularly preferred because of its relatively low cost and excellent properties. The caregiver also often rubs mineral oil and other oil-based ointments or lotions on children's skin to treat and / or prevent rashes.

[0104] Emollients are believed to alter the bonding of adhesives by two mechanisms. First, they migrate to the interface of the adhesive substrate and thus disrupt the bond. Second, the emollient absorbs into and plasticizes the adhesive which reduces the cohesive strength of the adhesive. Thus, the above hot melt adhesive compositions, upon exposure thereto, experience adhesive bond failure. As a result, the elastic leg bands of a disposable diaper can actually loosen from the diaper resulting in complete failure and degradation of the inner leg cuff. Also, construction adhesives can fail resulting in unwanted delamination of the absorbent article. Therefore, an adhesive that is capable of withstanding exposure to emollients while still providing sufficient bond strength would be highly desirable.

[0105] To determine efficacy against emollients, the permanent deformation resistance test was performed using the adhesives formulated according to Table 5.

[0106] The adhesives were coated on an SMS substrate with a coating weight of 15 g / m² using the spiral spray coating method described earlier herein. Three elastic Lycra strips, stretched 300%, were laminated between the two identical SMS substrates. Immediately after combining the non-woven substrates and Lycra strips to form a laminate, however, an emollient was applied in-line at a coating weight of 5 g / m² and, subsequently, the laminate was tested for elastic permanent set performance. The results are presented in Table 5 below.

ES 2 388 971 T3

TABLE 5

<td colspan="4">Reference EXAMPLES 10 - 11 (LOTION RESISTANT FORMULATION)</td>

<td></td><td>EX 10 (% p.)</td><td>EX 11 (% p.)</td><td>Control A</td>

<td></td><td></td><td></td><td></td>

<td>EOD02-07</td><td> 25</td><td> —</td><td></td>

<td>EOD02-08</td><td> —</td><td> 25</td><td></td>

<td>Hercotac 1148</td><td> 54,5</td><td> 54,5</td><td></td>

<td>Nyplast 222B</td><td> 20</td><td> 20</td><td></td>

<td>Irganox 1010</td><td> 0,5</td><td> 0,5</td><td></td>

<td>Uvitex OB</td><td> 0,01</td><td> 0,01</td><td></td>

<td></td><td></td><td></td><td></td>

<td>Viscosity (cP) 163 ° C (325 ° F)</td><td> 9050</td><td> 5560</td><td></td>

<td>Softening point mPa.s ° C (° F)</td><td> 108 (226)</td><td> 110 (230)</td><td></td>

<td></td><td></td><td></td><td></td>

<td>Coating T ° C (° F)</td><td> 191 (375)</td><td> 177 (350)</td><td> 177 (350)</td>

<td>'Permanent deformation (%)</td><td> 84</td><td> 85</td><td>Delaminated</td>

[0107] As can be seen, the adhesives performed exceptionally well as an elastic setting adhesive while also providing very good permanent set performance after exposure to the emollient. In comparison, the commercial styrenic block copolymer-based hot melt adhesive in Table 5 as Control A was delaminated under the same conditions.

Examples 12-30

[0108] Examples 12-30 were formulated using the same procedure as described herein above with the ingredients listed in Table 6. The comparative formulations of Examples 12 and 13 did not contain a secondary polymer while the formulations of the Examples 14 to 30 all contained one or more secondary polymers. Comparative Examples 12 and 13 had relatively low tensile strength and elongation, while the compositions containing the secondary polymers all had much higher tensile strength and / or elongation.

ES 2 388 971 T3

TABLE 6

<td></td><td>Ex. 12 *</td><td>Ex. 13 *</td><td>Ex. 14</td><td>Ex. fifteen</td><td>Ex. 16</td><td>Ex. 17</td><td>Ex. 18</td><td>Ex. 19</td><td>Ex. twenty</td><td>Ex. twenty-one</td><td>Ex. 22</td><td>Ex. 2. 3</td><td>Ex. 24</td><td>Ex. 25</td><td>Ex. 26</td><td>Ex. 27</td><td>Ex. 28</td><td>Ex. 29</td><td>Ex. 30</td>

<td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Nypast222B</td><td> 8,3</td><td> 10</td><td> 12</td><td> 12</td><td> 17</td><td> 16,5</td><td> 5</td><td> 5</td><td> 5</td><td> 10</td><td> 16</td><td> 14</td><td> 14</td><td> 10</td><td> 10</td><td> 4</td><td> 8</td><td> 8</td><td> 8</td>

<td>Hercotac1148</td><td> 45 5</td><td> 45,5</td><td> 58</td><td> 58</td><td> 61</td><td> 58</td><td> 55</td><td> 50</td><td> 50</td><td> 60</td><td> 55</td><td> 57,5</td><td> 57,5</td><td> 59,5</td><td> 59,5</td><td> 57,5</td><td> 58,5</td><td> 59,5</td><td> 59,5</td>

<td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Huntsman</td><td> 28,7</td><td> 27</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>RT2535</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Huntsman</td><td> 5</td><td> 5</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>RT2304</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Eastoflex 1003</td><td></td><td></td><td></td><td></td><td></td><td></td><td> 5</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td> 10</td><td> 10</td><td></td><td></td>

<td>Eastofiex1060</td><td></td><td></td><td> 9,5</td><td> 9,5</td><td></td><td> 5</td><td> 10,5</td><td></td><td> 20,5</td><td></td><td></td><td></td><td></td><td> 10</td><td> 10</td><td></td><td></td><td> 10</td><td></td>

<td>Vestoplast704</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td> 20,5</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Vestoplast 508</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td> 19</td>

<td>EOD-01-06</td><td> 12</td><td> 12</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td> 8</td><td> 8</td><td> 8</td><td> 8</td><td></td><td></td><td></td><td></td>

<td>EOD-02-07</td><td></td><td></td><td> 16</td><td> 16</td><td> 16</td><td> 15</td><td> 8</td><td> 8</td><td> 8</td><td></td><td> 8</td><td></td><td></td><td></td><td></td><td> 8</td><td> 8</td><td></td><td></td>

<td>EOD-02-15</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td> 4</td><td> 8</td>

<td>Kraton 1657</td><td></td><td></td><td> 4</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Kraton 1652</td><td></td><td></td><td></td><td> 4</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Tuftec SBBS-</td><td></td><td></td><td></td><td></td><td> 5,5</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>JT84P</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Elvax 150</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td> 16</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Kraton D1112</td><td></td><td></td><td></td><td></td><td></td><td> 5</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Engage 8407</td><td></td><td></td><td></td><td></td><td></td><td></td><td> 16</td><td> 16</td><td></td><td> 29,5</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Engage 8401</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td> 20,5</td><td></td><td></td><td></td><td></td><td></td><td></td><td> 13</td><td></td>

<td>Lotryl 35BA320</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td> 5</td><td></td><td> 12</td><td></td><td></td><td></td><td></td>

<td>Lotryl 28BA175</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td> 20</td><td> 15</td><td> 12</td><td></td><td> 15</td><td></td><td></td><td></td>

<td>Lotryl 7BA-01</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td> 5</td><td> 5</td><td></td><td></td>

<td>Irganox 1010</td><td> 0,5</td><td> 0,5</td><td> 0,5</td><td> 0,5</td><td> 0,5</td><td> 0,5</td><td> 0,5</td><td> 0,5</td><td> 0,5</td><td> 0,5</td><td> 0,5</td><td> 0,5</td><td> 0,5</td><td> 0,5</td><td> 0,5</td><td> 0,5</td><td> 0,5</td><td> 0,5</td><td> 0,5</td>

<td>Epolene C18</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td> 5</td>

<td>Orevac 9305</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td> 10</td><td></td><td></td>

<td>ExxelorVA1840</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td> 5</td><td></td>

<td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Viscosity</td><td> 11700</td><td> 10100</td><td> 7250</td><td> 6875</td><td></td><td> 4240</td><td> 10600</td><td> 12300</td><td> 8550</td><td> 11020</td><td> 11270</td><td> 5275</td><td> 4215</td><td> 5250</td><td> 4875</td><td> 6800</td><td> 5450</td><td> 19,45</td><td> 4550</td>

<td>Brookfield at 325</td><td>(cP)</td><td></td><td>(cP)</td><td>(cP)</td><td></td><td>(cP)</td><td>(cP)</td><td>(cP)</td><td>(cP)</td><td></td><td></td><td>(cP)</td><td>(cP)</td><td>(cP)</td><td>(cP)</td><td></td><td></td><td> 0</td><td></td>

<td>° F (163 ° C)</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>(mPa.s)</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Point of</td><td></td><td></td><td> (225</td><td> (227</td><td></td><td></td><td> (234</td><td> (228</td><td></td><td></td><td> (214</td><td> (234</td><td> (230</td><td> (239</td><td> (235</td><td></td><td></td><td></td><td></td>

<td>Soften.</td><td></td><td></td><td>° F)</td><td>° F)</td><td></td><td></td><td>° F)</td><td>° F)</td><td></td><td></td><td>° F)</td><td>° F)</td><td>° F&gt;</td><td>° F)</td><td>° F)</td><td></td><td></td><td></td><td></td>

<td>Herzog</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Tensile Strength (psi)</td><td> 84</td><td> 80</td><td> 138</td><td> 150</td><td></td><td> 102</td><td> 110</td><td> 150</td><td></td><td> 83</td><td> 154^Λ</td><td> 165</td><td> 165</td><td> 109^J</td><td> 94 '</td><td> 231</td><td> 177</td><td> 118</td><td> 170</td>

<td>Elongation</td><td> 94%</td><td> 88%</td><td> &gt;100</td><td> &gt;100</td><td></td><td> &gt;100</td><td> &gt;100</td><td> &gt;100</td><td></td><td> &gt;100</td><td> 900</td><td> &gt;100</td><td> &gt;100</td><td> &gt;100</td><td> &gt;100</td><td> &gt;100</td><td> 785</td><td> &gt;100</td><td> &gt;100</td>

<td> (%)</td><td></td><td></td><td> 0 %</td><td> 0 %</td><td></td><td> 0 %</td><td> 0</td><td> 0 %</td><td></td><td> 0 %</td><td> %</td><td> 0 %</td><td> 0</td><td> 0</td><td> 0</td><td> 0 %</td><td> %</td><td> 0 %</td><td> 0 %</td>

<td></td><td></td><td></td><td></td><td></td><td></td><td></td><td> %</td><td></td><td></td><td></td><td></td><td></td><td> %</td><td> %</td><td> %</td><td></td><td></td><td></td><td></td>

* Comparative example of an adhesive without a secondary polymer.

[0109] Nyplast 222B is a 47% naphthenic, 48% paraffinic and 5% aromatic mineral oil from Nynas USA.

[0110] Hercotac 1148 is a C5 / C9 hydrocarbon resin with a 94 ° C Softening Point from Eastman Chemical Products.

[0111] Epolene C 18 is a maleic anhydride treated polyethylene wax from Eastman Chemical Products.

[0112] Vestoplast 508 is a butene-rich APAO from Degussa Corp. with a target viscosity of 8000 mPa.s (80 Poise) at 190 ° C.

[0113] Eastoflex 1003 is a high methylene APAO from Eastman Chemical Products with a target viscosity of 2500 mPa.s (2.5 Poise) at 190 ° C.

[0114] Eastoflex 1060 is Eastman's average ethylene content APAO with a target viscosity of 6000 mPa.s (60 Poise) at 190 ° C.

[0115] Lotryl 7BA01 is an ethylene butyl acrylate copolymer containing 7% butyl acrylate and a melt index of 1 from Atofina Chemicals Inc.

ES 2 388 971 T3

[0116] Lotryl 28BA175 is an ethylene butyl acrylate copolymer containing 28% butyl acrylate and a melt index of 175 from Atofina Chemicals Inc ..

[0117] Lotryl 35BA320 is an ethylene butyl acrylate copolymer containing 35% butyl acrylate and a melt index of 320. It is available from Atofina Chemicals Inc.

[0118] Lotryl 28BA175 is an ethylene butyl acrylate copolymer containing 28% butyl acrylate and a melt index of 175. It is available from Atofina Chemicals Inc.

[0119] Orevac 9305 is an ethylene vinyl acetate / maleic anhydride terpolymer available from Atofina Chemicals Inc.

[0120] EOD-01-06 is a metallocene catalyzed RCP polymer with a melt index of 7 and a DSC softening point of 112 ° C available from Atofina Chemicals Inc.

[0121] EOD-02-07 is an mRCP copolymer with a melt index of 50 and a DSC softening point of 112 ° C from Atofina Chemicals Inc.

[0122] Engage 8407 is an ethylene / octene copolymer with a melt index of 30 with a density of 0.875 g / cm³ (0.875 g / cc). It is available from DuPont Dow Elastomers.

[0123] Engage 8401 is an ethylene / octene copolymer with a melt index of 30 with a density of 0.885 g / cm³ (0.885 g / cc). It is available from DuPont Dow Elastomers.

[0124] Exxelor VA1840 (MAH functionalized elastomeric copolymer) has an EPR backbone with medium maleic anhydride content from ExxonMobil. It is semi-crystalline and has an MFR of 27 (g / 10 min, 230 ° C / 10 kg).

[0125] Huntsman RT 2535 is a high ethylene APAO from Huntsman Chemical Co. It has a viscosity range at 190 ° C of 2800 to 4200 mPa.s (28.00 to 42.00 Poise) with a range of Softening Point of 260 to 276 ° F (127 to 136 ° C).

[0126] Huntsman RT 2304 is an APAO from Huntsman Chemical Co. with a medium ethylene content. The viscosity range at 190 ° C is 3500 to 5500 mPa.s (3.5 to 5.5 Poise).

[0127] Vestoplast 704 is a propene rich APAO from Degussa Corp. with a target viscosity of 3500 mPa.s (35 Poise) at 190 ° C.

[0128] Kraton G1657 is a styrene / ethylene-butylene / styrene block copolymer (SEBS) from Kraton Polymers with a 13/87% styrene / rubber ratio. Contains 30% diblocks by weight.

[0129] Kraton G1652 is a styrene / ethylene-butylene / styrene block copolymer (SEBS) available from Kraton Polymers with a 30/70% styrene / rubber ratio.

[0130] Tuftec SBBS-JT84P is a styrene / ethylene-butylene / styrene block copolymer containing 29% styrene from Asahi Rubber Co in Japan.

[0131] Elvax 150 is an ethylene / vinyl acetate (EVA) copolymer containing 33% vinyl acetate and having a melt index of 43. It is available from Dupont Chemical Co.

[0132] Kraton D1112P is a linear styrene / isoprene / styrene block copolymer available from Kraton Polymers. It has a styrene / rubber ratio of 15/85% and contains 38% diblocks.