Loop material for loop and hook type fastener used in a disposable article or garment

[0001] The present invention relates to a loop material for the hook and loop (Velcro) fastener used in a disposable article or outfit.

Background of the invention [0002] The applications of hook and loop fasteners in consumer and industrial applications are widely known. Examples of such applications include disposable hygienic absorbent products such as diapers, disposable costumes such as surgical gowns, and the like.

[0003] In general, the hook and loop fasteners comprise a hook component and a loop component. The hook component includes many hook-shaped members anchored to the base material. The loop component includes a plurality of upright loop members protruding outwardly from the backing material. The hook-shaped members are designed to engage loop members to provide a strong mechanical connection between them. Hook members and loop members can usually be repeatedly engaged and uncoupled.

[0004] However, when the hook-and-loop fastener is to be used in a disposable hygienic absorbent product or disposable outfit, a low-cost loop element that works to sufficiently provide a releasable mechanical closure with a limited number of uses is desirable. There is no need for the loop element of the disposable product to have a long-term ability to repeatedly connect and disconnect with the hook element, since such products have only a short life span. However, the loop component used in conjunction with the hook component should provide a relatively high peel strength and relatively high shear strength, i.e. it should provide a secure closure during a limited number of use cycles.

[0005] US 2003/0077430 relates to a nonwoven laminate material for mechanical closing systems that comprise at least one layer of continuous filament polyolefin nonwoven fabric, and a second layer that is bonded to the first layer. The second layer includes a sheet of crimped primary fibers.

[0006] US 2005/0208259 relates to a loop material for mechanical closing systems, said loop material comprising a layer of fibers lying on a flexible backing in the form of a sheet. The fibers are placed in discontinuous regions of attachment of the ground.

[0007] US 5 326 612 A1 relates to an outer component for a hook and loop fastener. Said outer component comprises a nonwoven web attached to the substrate, said nonwoven having a surface mass between 6 and 42 g / m² and said nonwoven web may comprise a carded or spunbond type.

[0008] US 6 770 065 B1 relates to an outer material for a hook and loop fastener, said outer material is made of a nonwoven having a surface mass comprised between 20 and 80 g / m2, said nonwoven contains fibers having a degree of fineness of 4 to 15 denier.

[0009] JP 2002/315607 relates to an outer material for a hook and loop fastener, said outer material comprises a sheet of base material made of thermoplastic resin and nonwoven, both of which are partly ultrasonically welded.

[0010] US 2006/0019572 relates to an outer material for a hook and loop fastener, said loop material comprising a binder-free nonwoven material having a bottom layer and a top layer, said nonwoven fabric can further be connected by means of a hot calendering roll island thereby forming a bonded area and non-bonded area.

[0011] There are many loop materials available. Typical loop materials include knitted fabrics or nonwovens laminated to a thin layer for support. These loop materials are typically processed on diaper lines, by unwinding material from a roll, applying adhesive to the back, on the side of a thin layer of loop material, feeding the material onto a perforated metal cylinder that holds the material in place by vacuum suction, cutting the material into belts while it is held by a cylinder and by applying straps to diaper pants material, which is fed in parallel through the diaper production line.

[0012] Polypropylene is preferred for the production of nonwoven materials for diaper applications because of their relatively low cost, softness, availability and ease of processing. For nonwoven loop materials, it would be desirable to eliminate the use of a thin layer support layer to further reduce costs and improve the softness and elasticity of the loop material.

[0013] However, several problems have been encountered that limit the use of nonwovens for use as loop fastening materials. They will be discussed in turn.

[0014] Typical nonwoven materials are too air permeable. Such high-permeability materials cannot be effectively held in place during belt cutting operations on typical existing vacuum cylinders of the diaper production line. In order to use such high-permeability materials, extensive modification of vacuum cylinders and related devices was required.

[0015] Typical polypropylene-based nonwovens are susceptible to compression. When the nonwoven loop materials are wound into rolls and stored for some time, the areas of the loops can be permanently compressed. When the roll of nonwoven loop material is unrolled, processed in the diaper line, the pieces are cut and attached to the bottom layer of the diaper, the loop may be so flat that it is not useful as an effective fastening material.

[0016] The non-woven fibers and filaments must be joined together to secure the structure together, as well as leave areas of unbound fibers or loops available for attachment with a suitable hook. If an insufficient percentage of the nonwoven flat area is bonded, the nonwoven fibers can easily be pulled out of the structure after retracting the hook when opening the fastener. If too high a percentage of the flat nonwoven area is bonded, there is not enough loop fiber for hook coupling and the hook capacity is too low. In addition, the combined design has a large impact on the hook coupling ease and thus the attachment effect.

[0017] There is a need for a low cost nonwoven for use as a loop fastening material for use in hygienic applications such as diapers that overcome these problems.

Summary of the Invention [0018] The hook and loop fastener material is a composite nonwoven fabric according to the appended claim 1.

Description of the drawings [0019] To illustrate the invention, the Figure shows an embodiment that is currently preferred; it being understood that the invention is not limited to the exact systems and tools shown.

Fig. 1 is a cross-sectional view of the nonwoven composite according to the present invention.

Fig. 2 is a top plan view of one embodiment of a nonwoven composite made in accordance with the present invention.

Fig. 3 is a top plan view of one embodiment of a nonwoven composite made in accordance with the present invention.

Fig. 4 is a top view of the "islands".

Fig. 5 is a schematic illustration of the method for producing the present invention.

Fig. 6 is an illustration related to the example below.

Description of the invention [0020] Referring to Figure, in which similar numbers mean similar elements, Fig. 1 shows an embodiment of a nonwoven composite 10. The nonwoven composite 10 includes a loop layer 12, a backing layer 14, and a plurality of bonded areas 16. Each of these items will be discussed in detail below.

[0021] The nonwoven composite 10 is to be a loop component of the hook and loop fastener (not shown) for a disposable article / outfit. The disposable article / outfit includes disposable hygiene absorbent products (such as diapers) and disposable clothing (such as surgical gowns). Disposable, generally, refers to single use.

[0022] In the nonwoven composite 10, the loop layer 12 and the backing layer 14 are in contact with the face surfaces and are joined together by an interconnected area 16. The nonwoven composite 10 may comprise at least two different nonwoven materials. The loop layer 12 forms a "hill" in non-bonded areas so that the nonwoven loop layer is open and adapted for hook coupling. The loop layer 12 in the combined areas is flat, whereby the loop layer is closed and not adapted for hook coupling. The total air permeability of the nonwoven composite 10 should not exceed 1500 l / m²/ S. In one embodiment, the permeability should not exceed 1300 l / m²/ S. In another embodiment, the permeability should be 800 l / m²/ S. The upper limits of permeability are the threshold at which the nonwoven composite works well in the diaper manufacturing process (as discussed above), and the lower limits represent the threshold at which the nonwoven composite has sufficient flexibility (i.e., it does not give a stiff feeling like foil). Permeability is measured using an air permeability tester III, model FX 3300 from Textest AG from Zurick in Switzerland.

[0023] The loop layer 12 is adapted to, inter alia, engage the hooks (not shown) of the hook and loop fastener. The loop layer 12 is a carded web made of thermoplastic crimped base fibers. Primary fibers have dTEX in the range of 1.5 to 6.0. The area weight of the carded nonwoven is in the range of 10 to 35 g / m2². Alternatively, the surface mass can be in the range of 18 to 27 g / m2². Before incorporation of the nonwoven web 10 into the composite, the carded nonwoven web is unbound. The term thermoplastic, as understood herein, refers to any thermoplastic material. Thermoplastic materials include, but are not limited to, polyolefins, polyesters, nylons, and combinations thereof. Polyolefins include, but are not limited to: polyethylene, polypropylene, polybutene, polymethylpentene, their copolymers and blends thereof. Polyesters include, but are not limited to: PET, PBT, their copolymers and blends thereof. In one embodiment, the thermoplastic material is polypropylene.

[0024] The backing layer 14 is adapted to, inter alia, hold the fibers of the loop layer 12 in place, providing a surface such that the loop layer 12 can be attached to the article / outfit (not shown), and to facilitate folding of the article / outfit. The backing layer is a spunmelt nonwoven made of thermoplastic fibers. A spunmelt nonwoven fabric, as used herein, refers to a nonwoven fabric made using a spunmelt process. A spunmelt process is a combination of spunbond (S) and meltblown (M) processes. The spunmelt nonwoven may have an SM or SMS or SMMS structure or the like. The surface weight of the spunmelt nonwoven may be in the range of 5 to 30 g / m2². Alternatively, the surface mass can be in the range of 11 to 17 g / m2². The spunmelt fabric can be adapted to reduce air permeability. Reduced air permeability is useful in the manufacture of an article / outfit when the nonwoven composite is attached to the article / outfit. The backing layer 14, when manufactured, can be calendered before the nonwoven composite 10 is assembled. After this calendering, one side is "smooth", that is, there are no recesses from the pattern roller. The smooth side may be the exposed side of the nonwoven composite 10 and may be printed. Thermoplastic, as used herein, refers to any thermoplastic material. Thermoplastic materials include, but are not limited to, polyolefins, polyesters, nylons, and combinations thereof. Polyolefins include, but are not limited to: polyethylene, polypropylene, polybutene, polymethylpentene, their copolymers and blends thereof. Polyesters include, but are not limited to: PET, PBT, their copolymers and blends thereof. In one embodiment, the thermoplastic material is polypropylene.

[0025] Bonded areas 16, as used herein, refers to areas in which the loop layer and the backing layer are connected to each other and where the nonwoven composite is substantially impermeable. "Essentially impermeable" refers to the permeability to non-bonded areas in which air can pass through the nonwoven composite. In combined areas, air cannot pass (or no more than 5% of the air that passes through the unsaturated area), while in non-bonded areas, air can pass through the nonwoven composite. Bonded areas 16 may contain about 35 to 55% of the surface area of ​​the loop material. Bonded areas 16 may contain 40-50% of the surface area of ​​the loop material. The associated areas 16 may be lines or waves (continuous or discontinuous) as illustrated, for example in Figs. 2 and 3; but they are not "islands" 19, as illustrated, for example in Fig. 4. In one embodiment, the combined areas are positioned transversely to the machine direction. Hooks (not shown) will not engage the nonwoven composite in bonded areas, but the hooks will engage the composite nonwoven in non-bonded areas. As shown in Fig. 1, the combined height of the loop layer 12 and the backing layer 14 in the combined areas is less than the height of the backing layer 14 in the non-bonded areas.

[0026] When the bonded areas 16 are lines or waves, the length of the loop is the distance between the bonded areas. The length of the loops in the loop material may be equal to or substantially equal to. In the machine direction, the length of the loops can be 1-4 mm or 23 mm. The height of the loop is the distance between the backing layer 14 and the uppermost portion of the loop layer 12. The height of the loop is substantially equal between the non-bonded areas.

[0027] The nonwoven composite 10 is produced as follows: see Fig. 5: the first spunmelt band 20 is formed by extruding thermoplastic resin fibers. This band is then merged by calendering. Second band 22 is produced by scraping crimped base fibers to produce a band that is not integrated. The two bands are then superimposed (i.e., the faces facing each other). The resulting web consisting of two superimposed bands is passed through a hot calender 24 (roll 26 being, for example, a pattern roller, and roll 28 being, for example, a smooth roll) to achieve the following results: consolidation of the card web by bonding the crimped primary fiber into multiple zones connecting both networks along multiple binding zones. In the calendering process, the webs will be fused at or near the melting point of the thermoplastic polymer from which the nonwoven fabric is made. It is important that the process takes place at a temperature and pressure sufficient for proper combined networks. Then, the nonwoven composite is rolled up 30.

Example

Comparison of the results of the 180 degree peel test [0028] The results of the 180 degree peel test are compared for nonwoven composites that were produced with a relatively low percentage of bonded area and bonding pattern according to the present invention. The peel test was performed using a tensile test machine, Model No. MTC Alliance RT / 5 from MTS Systems Corporation of Eden Prairie, MN.

[0029] The reference rolls of each of the nonwoven composites were produced using the combined standards described below, and then cut into rolls and wound with the same voltage level. One of the rolls was then stored for at least two weeks. Samples were then taken from similar locations in each of the rollers and tested with a 180 degree peel test, see Fig. 6.

[0030] The 180 ° peel test requires that the hook element is attached to the loop element of the hook and loop fastening system, and then the tearing of the attachment of the hook element from the loop element at an angle of 180 °. The maximum load needed to disconnect both components is recorded in Newtons.

Test Roll 1 cut out [0031]

SMS basic layer: 14 g / m2²

Top layer of carded fiber: 23 g / m2² combined area: 17.4%

Pattern: Islands (See Fig. 4)

180 degree peel removal test using the Aplix 94x hook prototype (13 mm tape width with mushroom-shaped hooks with a density of 385 hooks / cm²)

Samples taken from the roll 21 days after cutting the reference roll

Test Roll 2 cut out [0032]

SMS basic layer: 14 g / m2²

Top layer of carded fiber: 23 g / m2²

Combined area: 42%

Pattern: Horizontal discontinuous waves (See Fig. 3)

180 Gradual peel test using the Aplix 94x hook prototype (13 mm strip width with mushroom-shaped hooks with a density of 385 hooks / cm²)

Samples taken from the roll 21 days after cutting the reference roll

Trial Roll Cut Out 1

<td>Place of sample</td><td>Roll model</td><td>AND</td><td>B</td><td>C</td><td>D</td>

<td>180 ° test peeling, N *</td><td> 5,6</td><td> 3,5</td><td> 3,0</td><td> 4,4</td><td> 2,8</td>

Trial Roll Cut Out 2

<td>Place of sample</td><td>Roll model</td><td>AND</td><td>B</td><td>C</td><td>D</td>

<td>180 ° Test on tearing off, N *</td><td> 5,3</td><td> 5,3</td><td> 5,0</td><td> 5,3</td><td> 4,9</td>

* average of ten data points

Aplix Inc., United States of America Dounor Sas, France

Proxy:

EP 2 137 346 B1

Z-15948/17