KR20010089718A - Heat Shrinkable Elastomeric Laminate Material - Google Patents

Abstract

The present invention provides a stretchable laminate made of an elastic sheet layer bonded and pre-stretched to one or more extensible layers. In a first aspect, the elastic layer is attached to the stretchable layer at a selected location and then heated. The potential extensibility of the pre-stretched elastic layer and the extensibility of the stretchable layer produce the desired extensibility useful as side panels and side tabs of waistbands, diapers, and training pants. Because of this improved extensibility, training pants and diapers made from these materials can fit a wider range of body sizes. In a second aspect, the film is predrawn in the transverse and longitudinal directions and then laminated to the stretchable layer to produce two-way stretch. The elastic layer can have an opening. Opening formation allows the manufacture of breathable laminates while maintaining improved stretchability.

Description

Heat Shrinkable Elastomeric Laminate Material

The goal of diaper manufacturers is to have a diaper of one size that is suitable for multiple users so as to reduce the number of different diapers needed, thereby reducing storage space and inventory requirements in the store. In response to these needs, the sides (also known as ears or tabs) of the diaper are designed to be stretched as much as possible while maintaining strength and tear resistance. New materials and processing methods have been developed to meet these needs. In general, improving elasticity degrades material properties and reduces strength. There is a continuing need to improve the elasticity of tabs while maintaining strength.

Elastic materials are desired for personal care and other garment products to provide the wearer with the desired compliance. Film extrusion and meltblowing are two ways to easily produce low cost elastic sheet materials.

Conventional nonwovens such as conventional spunbond fabrics are not particularly elastic. Conventional spunbond fabrics and laminates of elastic films or elastic meltblown fabrics have slight elasticity. Stretchable fabrics, such as stretchable nonwovens, such as stretchable necked spunbond fabrics, stretch in their stretch direction, but have low recovery rates. Laminates of stretchable fabrics and elastic films or elastic meltblown fabrics are stretchable as well as recoverable. However, there are inherent limitations to the maximum stretching and recovery that can be obtained with stretchable fabrics and elastic films or elastic meltblown fabrics. It is desirable to use stretchable materials and laminates of elastic films or elastic meltblown fabrics to impart better stretchability and recovery properties.

Some elastic film materials have a certain amount of "potential" stretch inherent therein. In order to "activate" extensibility, the film is often heated to shrink. When pulled, the activated film stretches and recovers. Thus forming a laminate of an elastic film and an inextensible fabric yields a material with limited stretchability. However, heating this material causes shrinkage to yield a fabric that can be stretched to its original unheated size. Despite this stretching, improvements are still needed. It is desirable to improve the stretch properties of the elastic film to non-stretch fabric laminate without substantially altering the composition of the material or the overall manufacturing technique.

Summary of the Invention

Generally speaking, in the first aspect, the present invention provides an elastic sheet layer provided in a pre-stretched state in the transverse direction (CD). One or more CD stretchable layers and elastic sheets are laminated to each other. The multilayer material is then preferably heated to shrink the elastic sheet in the CD direction to cause CD gathering of the CD stretchable layer. This material has good CD direction stretchability based on both the latent energy of the film and the stretchability of the stretchable layer.

In a second embodiment, the predrawn film is predrawn to fix in both the CD direction and the longitudinal direction (“MD”). One or more extensible layers and elastic sheets extending in either the CD direction or the MD direction, or both the CD and MD direction, are laminated to each other as done in the first embodiment. The laminate is heated to cause film layer shrinkage and gathering of the stretchable layer in both the CD and MD directions. Materials made in this way will be extensible in both the CD and MD directions. The material has good stretchability in the direction (s) in which the stretchable layer is stretched, based on both the stretchability of the stretchable layer and the potential energy of the film.

In a third aspect, the elastic sheet layer is provided predrawn only in the MD direction. One or more MD stretchable layers and elastic sheets are laminated to each other. The multilayer material is then preferably heated to shrink the elastic sheet in the MD direction and cause MD gathering of the MD stretchable layer. This material has good MD direction stretchability based on both the stretchable layer and the potential energy of the film.

In a fourth aspect, openings are formed in an elastic sheet layer, such as an elastic film, in a multilayer material. This opening formation creates a multilayer material that is breathable while maintaining improved stretchability.

Accordingly, it is an object of the present invention to provide a fabric having improved stretchability and plastability.

It is another object of the present invention to provide a material suitable for use as side panels for diapers, training pants and incontinence protection products.

It is another object of the present invention to provide a heat shrinkable laminate material comprising a heat shrinkable elastic film and at least one extensible layer.

It is another object of the present invention to provide a material suitable for use as a tab of a diaper or similar product.

It is a further object of the present invention to provide a fabric having the desired extensibility, which can function as a liner, and which also allows fluids and semi-fluids such as to pass urine.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of the invention in conjunction with the appended claims.

The present invention is directed to a nonwoven laminate material having improved elongation and recovery while maintaining strength. More specifically, the present invention provides laminates of elastic sheets and stretchable sheets. The laminate can be heated to cause shrinkage and optionally form openings.

Justice

As used herein, the term "nonwoven" fabric or web refers to a web having a structure in which individual fibers or yarns are entangled but not in a regularly repeating pattern as in reticular or knitted fabrics. Nonwovens or webs may be fabricated in various ways, such as, for example, meltblowing, spunbond, hydroentangling, air-laid and bonded carded webs. It has been produced by the method.

As used herein, the term “spunbond fiber” is described, for example, in US Pat. No. 4,340,563 (Appel et al.), 3,692,618 (Dorschner et al.), 3,802,817 (Matsuki et al.), Molten thermoplastic materials as described in 3,338,992 and 3,341,394 (Kinney), 3,502,763 (Hartman), 3,542,615 (Dobo et al.) And 5,382,400 (Pike et al.) Refers to small diameter fibers formed by extruding as filaments from a plurality of fine, usually circular, capillary spinnerets and then rapidly reducing the diameter of the extruded filaments. Spunbond fibers are generally non-sticky when they are deposited on the collecting surface and are usually continuous. Spunbond fibers usually have a diameter of about 10 microns or more. However, microfiber spunbonds are commonly assigned U. S. Patent Application Serial No. 08 / 756,426 (filed Nov. 26, 1996, filed April 30, 1998, Mormon et al.) And U.S. Patent No. 5,759,926 (Pike et. It can be accomplished by a variety of methods, including but not limited to those described in al.).

As used herein, the term “meltblown fibers” refers to a high speed of convergent fastening which generally thins the filaments of the molten thermoplastic material and reduces their diameter through a plurality of fine, usually circular die capillaries. By ordinary, it is meant a fiber of polymeric material formed by extruding as molten yarn or filaments into a hot gas (eg air) stream. The meltblown fibers can then be carried by the high velocity gas stream and deposited on the collecting surface to form a web of meltblown fibers that are irregularly dispersed. Such a method is described, for example, in US Pat. No. 3,849,241 to Butin et al. Meltblown fibers can be continuous or discontinuous and are generally tacky when deposited on the collecting surface. Meltblown fibers may comprise microfiber webs.

As used herein, the term “polymer” generally includes, but is not limited to, homopolymers, copolymers (eg, blocks, grafts, random and cross copolymers), terpolymers, and the like, and blends and modifications thereof. Do not. In addition, unless otherwise defined, the term "polymer" includes all possible spatial arrangements of the molecule. Such arrangements include, but are not limited to, isotactic, syndiotactic, and random symmetry.

As used herein, the term "longitudinal" or MD means the length of the fabric in the direction in which the fabric is made. The term "lateral" or CD means the width of the fabric, ie, generally the direction perpendicular to the MD.

As used herein, the term "cross-direction" means the transverse to the direction in which the material is drawn.

As used herein, the term "extensible" means that it can be stretched or stretched in more than one direction.

As used herein, the term "recovery" refers to the contraction of the stretched material when the bias force is terminated after stretching the material by applying a biasing force. For example, if a 50% stretch of a 2.54 cm (1 inch) relaxed and unbiased length of material is stretched to a length of 3.81 cm (1.5 inches), the material will have a stretched length that is 150% of its relaxation length. will be. If the illustrated stretched material shrinks, i.e., recovers to a length of 2.79 cm (1.1 inches) after removing the bias and drawing force, the material will recover to 80% (1.02 cm (0.4 inches)) of its elongated length. will be.

The term "elastic", as used herein, has an elongated biased length that is elongated, ie elongated to apply a biasing force, which is 150% or more greater than the relaxed non-biased length, and at least 50% of its elongated length when removing elongating force. Omrad as says the material. One hypothetical example is a sample of 2.54 cm (1 inch) material that can stretch beyond 3.81 cm (1.50 inch) and have a length less than 3.18 cm (1.25 inch) when the biasing force is removed.

As used herein, the term “inelastic or nonelastic” refers to any material that is not within the definition of “elastic”.

As used herein, the term "neckable material" refers to any material that can be necked.

As used herein, the term "necked material" refers to any material that has been at least one dimension narrowed by, for example, stretching or gathering.

As used herein, the term "necking" refers to, for example, making the speed of the second niproll assembly faster than the speed of the first niproll assembly, passing one end of the material through the first niproll assembly, and then the second Any of several processes known to those skilled in the art of passing the nip roll assembly. The difference in speed draws the material longitudinally between the nip roll assemblies so that the material is necked in.

As used herein, the term "personal protective product" refers to diapers, training pants, absorbent panties, adult incontinence products, feminine hygiene products and similar functional products.

Detailed Description of the Preferred Embodiments

In general, the present invention provides an elastic fibrous nonwoven laminate comprising an elastic film layer and one or more first extensible fibrous nonwoven web facing layers. If desired, additional stretchable layers may be attached to the laminate, for example, as a second stretchable fibrous nonwoven surface layer on the surface of the elastic substrate layer facing the first stretchable surface layer. For clarity, the term "layer" generally refers to a single piece or sheet of material, but should also be interpreted to mean multiple sheets or piles of material that together form one or more "layers" described herein.

The stretchable nonwoven layer is preferably formed of a spunbond. The spunbond material consists of polyolefins selected from the group consisting of polypropylene, polyethylene and copolymers of propylene and ethylene suitable for spunbond processing. Preferred polypropylenes are available as Exxon® PD 3445 polypropylene (hereinafter sometimes referred to as "PP"), available from Exxon Chemical Company, Houston, Texas. In addition, Exxon® PD 3445 is a low viscosity polypropylene typically used for meltblowing applications, such as Montell® PF 015 polypropylene commercially available from Montel Chemical, Wilmington, Delaware, USA. Sometimes referred to as "Montell® PD 015" and Exxon® PD 3445 present in the range of approximately 50 to 100%, more preferably approximately 66%, to provide an acceptable mixture. Revealed. 100% Exxon® PD3445 provided higher quality than using a blend of narrow molecular weight distribution polypropylene resin with low melt viscosity, for example MF (at 230 ° C.) at about 35 g / 10 Found greater than minutes. However, it should be understood that the blend may be used for a specific purpose. When a copolymer of propylene and ethylene is used, the ethylene content is present at a concentration of about 7% or less and propylene is present at a concentration of about 93% or more. It should be understood that bicomponent, multicomponent and multicomponent fibers may be used with the present invention.

Spunbond fibers are made according to one of the methods described above.

The elastic sheet is an elastic polyester, an elastic polyurethane, an elastic polyamide, an elastic polyolefin, a metallocene catalyzed polyolefin, and an elastic ABA 'block copolymer, wherein A and A' are the same or different thermoplastic polymers, and B is elastic Preferably an elastomeric polymer selected from the group consisting of polymer blocks). Preferred polymers are KRATON® G-2755 compounds, which are blends of elastomers, polyolefins and tackifying resins. Any tackifying resin can be used provided it is compatible with the elastomer and can withstand high processing (eg extrusion) temperatures. If blending materials are used, for example polyolefins or thick oils, the tackifying resins must also be compatible with these blending materials. In the case of the KRATON® elastomer, the REGALREZ and ARKON P series tackifiers are examples of hydrogenated hydrocarbon resins. ZONATAK (trade name) 501 light is an example of a terpene hydrocarbon. REGALREZ (trade name) hydrocarbon resin is commercially available from Hercules Incorporated. ARKON® P Series resins are available from Araca and Chemicals, Inc., USA. Of course, the present invention is not limited to using these three tackifying resins, and other tackifying resins may also be used as long as they are compatible with other components of the composition and can withstand high processing temperatures.

Polyolefins can also be blended with an elastomer to improve the processability of the composition. The polyolefin should be extrudable in blended form with the elastomer, if so blended and subjected to elevated pressure and elevated temperature conditions suitably combined. Examples of useful blended polyolefin materials are polyethylene, polypropylene and polybutene, including ethylene copolymers, propylene copolymers and butene copolymers. Particularly useful polyethylenes can be obtained from Equista Chemicals, Cincinnati, Ohio, under the trade name PETROTHENE® NA601 (also referred to herein as PE NA601 or polyethylene NA601). Two or more polyolefins may be used.

The pressure sensitive elastomeric adhesive formulation may include, for example, about 20 to about 99 weight percent elastomer, about 5 to about 40 percent polyolefin, and about 5 to about 40 percent resin tackifier. For example, the composition KRATON® G-2755 comprises about 61 to about 65% KRATON® G-1659, about 17 to about 23% polyethylene NA-601 (Equista, Cincinnati, Ohio). Commercially available from Chemicals), and from about 15 to about 20% REGALREZ® 1126. Other beneficial additives may be flow modifiers to penetrate the polymer melt into the fiber structure, and surface tension modifiers to reduce the elastomer melt and fiber structure surface tension differences. Flow modifiers can be added to the elastomer to reduce the elastomer melt viscosity. Flow modifiers for KRATON® elastomers include low molecular weight polyolefins.

The elastic sheet can be formed, for example, from (polystyrene / poly (ethylenebutylene) / polystyrene) block copolymers available from Shell Chemical Company under the trade name KRATON®G. Such block copolymers can be, for example, KRATON® G-1659. Other exemplary elastic materials that can be used to form the elastic sheet include polyurethane elastic materials, such as B.F. Polyurethanes available under the tradename ESTANE® from Goodrich Co., Ltd., elastomeric materials such as Atochem, Polymers (RILSAN®), Glen Rock, NJ, under the tradename PEBAX® Ether-block-amides, and polyester elastic materials, such as those commercially available from E.I.Dupont Dnemour & Company, under the tradename HYTREL®. Formation of elastic sheets from polyester elastic materials is disclosed, for example, in US Pat. No. 4,741,949 (Morman et al.) And US Pat. No. 4,707,398 (Boggs). Sheets made from the thermoplastic elastomeric compositions disclosed in U.S. Patent No. 5,182,069, available from EXXON Chemical Company as EXX-601, are also available in the present invention. This material is provided in a pre-stretched state in the transverse direction.

Films are discussed herein as preferred materials; However, heat shrinkable elastic foams, such as meltblown fibrous webs and heat shrinkable woven or knitted elastic sheets, ie any heat shrinkable elastic sheets, may also be used and contemplated within the scope of the present invention.

Elastic thermoplastic polymers useful in the practice of the present invention are block copolymers such as polyurethanes, copolyether esters, polyamide polyether block copolymers, ethylene vinyl acetate (EVA), block copolymers having the formula ABA 'or AB, such as Copoly (styrene / ethylene-butylene), styrene-poly (ethylene-propylene) -styrene, styrene-poly (ethylene-butylene) -styrene, polystyrene / poly (ethylene-butylene) / polystyrene, poly (styrene / Ethylene-butylene / styrene) and the like.

Useful elastomers include the formula ABA 'or AB, where A and A' are thermoplastic polymer endblocks, each having a styrene moiety, such as poly (vinyl arene), and B is an elastomeric intermediate block, such as conjugated diene or lower alkene polymers. Is a block copolymer). Block copolymers of type AB-A 'may have the same or different thermoplastic block polymers for A and A' blocks, and the block copolymers of the present invention are intended to include linear, branched and radial block copolymers. . In this regard, the radial block copolymer may be referred to as (AB) _m -X, where X is a multifunctional atom or molecule, and each (AB) _m is radiated from X so that A becomes an endblock. In radial block copolymers, X can be an organic or inorganic polyfunctional atom or molecule, and m is an integer having the same value as the functional group originally present in X. It is usually 3 or more, often 4 or 5, but is not limited thereto. As such, the expression “block copolymer” and “ABA” and “AB” block copolymer in the present invention may be extruded as described above (eg by melt blowing), and the number of blocks is not limited to rubber blocks. And all block copolymers having thermoplastic blocks. The elastic nonwoven web can be formed, for example, from an elastic (polystyrene / poly (ethylene-butylene) / polystyrene) block copolymer. Commercially available examples of such elastomeric copolymers are those known as KRATON® materials available from Shell Chemical Company, Houston, Texas. KRATON® block copolymers are available in several different combinations, many of which are identified in US Pat. Nos. 4,663,220 and 5,304,599.

Polymers consisting of elastic A-B-A-B tetrablock copolymers can also be used in the practice of the present invention. Such polymers are discussed in US Pat. No. 5,332,613 to Taylor et al. In such polymers, A is a thermoplastic polymer block and B is an isoprene monomer unit substantially hydrogenated to a poly (ethylene-propylene) monomer unit. Examples of such tetrablock copolymers are SEPSEP elastomeric block copolymers or styrene-poly (ethylene-propylene) -styrene-poly (available under the trade name KRATON G-1730 from Shell Chemical Company, Houston, TX, USA). Ethylene-propylene).

Another suitable material is a polyester block amide copolymer having the formula:

Wherein n is a positive integer, PA represents a polyamide polymer fragment and PE represents a polyether polymer fragment. In particular, the polyether block amide copolymers have a melting point of about 150 ° C. to about 170 ° C. measured according to ASTM D-789; Melt index from about 6 g / 10 min to about 25 g / 10 min measured according to ASTM D-1238, Condition Q (235 ° C./1 kg load); from about 20 Mpa to about 200 measured according to ASTM D-790 Flexural modulus of Mpa; Tensile strength at break of about 29 Mpa to about 33 Mpa measured according to ASTM D-638; And an ultimate elongation at break of about 500% to about 700% measured according to ASTM D-638. Certain embodiments of the polyether block amide copolymers have a melting point of about 152 ° C. measured according to ASTM D-789; A melt index of about 7 g / 10 minutes measured according to ASTM D-1238, Condition Q (235 ° C./1 kg load); Flexural modulus of about 29.50 Mpa, measured according to ASTM D-790; Tensile strength at break of about 29 Mpa measured according to ASTM D-639; And an elongation at break of about 650% measured according to ASTM D-638. Such materials are available in various grades under the trade name PEBAX®. Examples of the use of such polymers can be found in US Pat. Nos. 4,724,184, 4,820,572 and 4,923,742 (Killian et al., Assigned to the same assignee as the present invention).

Elastomeric polymers also include copolymers of ethylene with one or more vinyl monomers such as vinyl acetate, unsaturated aliphatic monocarboxylic acids and esters of such monocarboxylic acids. The formation of elastic copolymers and elastic nonwoven webs from these elastic copolymers is disclosed, for example, in US Pat. No. 4,803,117.

Thermoplastic copolyester elastomers include copolyetheresters having the formula:

Wherein "G" is selected from the group consisting of poly (oxyethylene) -α, ω-diol, poly (oxypropylene) -α, ω-diol, poly (oxytetramethylene) -α, ω-diol, "a" and "b" are positive integers including 2, 4 and 6, and "m" and "n" are positive integers including 1-20. The materials generally have an elongation at break of about 600 to 750% measured according to ASTM D-638 and a melting point of about 176 to 205 ° C. (about 350 ° F. to about 400 ° F.) measured according to ASTM D-2117.

Commercially available examples of such copolyester materials include those known as ARNITEL®, previously available from Akcho Plastics, Arnhem, The Netherlands, and now from DSM, Siartt, The Netherlands, or Leemington, Delaware, USA. .children. And those known as HYTREL® available from DuPont Dnemour.

The elastic sheet may be formed by any of various methods known to those skilled in the art, such as, but not limited to, extrusion. The elastic sheet may be formed prior to lamination and deployment from the feed roll, or just prior to lamination (ie, the same processing step). In a first aspect, the elastic sheet is provided preliminarily and fixed in the CD direction. A preferred material, EXX-601, is provided as a roll of predrawn material.

Elastic sheets and stretchable layers, in particular necked nonwoven layers, can be any of several adhesion techniques known to those skilled in the art, such as calendering, adhesives (blending among components, on the surface of the components, between components, the matrix of each sheet). Disperse, etc.), acoustic and ultrasonic bonding techniques, entanglement, squelch adhesion, in-air adhesion, etc., but may be glued together at spaced apart locations.

The laminate is then heated to cause shrinkage of the elastic sheet to gather the stretchable nonwoven layer. The heating is from about 1 to about 6 minutes, more preferably from about 1 to about 68 degrees Celsius, more preferably from about 54 degrees Celsius to about 66 degrees Celsius, even more preferably from about 60 degrees Celsius to about 66 degrees Celsius. About 4 minutes, even more preferably about 1 to about 3 minutes. In a preferred embodiment the laminate is heated at 66 ° C. for 1 to 2 minutes. After cooling, the material is wound on a winding roll. Alternatively further processing or manufacturing steps may be performed simultaneously. In the manufacturing process, the heating step is performed after the laminate is cut and attached to the diaper or other desired product to heat the entire diaper, for example in an oven.

The first layer can also be a laminate of thermoplastic elastomers and adhesives that can potentially be made shrinkable. The adhesive may be deposited on the elastomer and coextruded with the elastomer or laminated by other methods known to those skilled in the art.

The material of the first aspect is the sum of the stretchability achieved in the laminate as a result of elongation of the necked in facing and heat shrinkage of the elastic sheet. That is, the amount of actual stretchability of the laminate material of the present invention is that of the laminate with the non-stretchable facing bonded to the heat shrinkable elastic sheet, or the stretchable facing, for example the neck-in facing facing bonded to the heat non-shrinkable elastic sheet. Can be much higher than This is particularly important for many purpose applications, such as stretchable waistbands and side panels of training pants, and much higher CD stretching than can be achieved with stretchability present in the prior art, eg, necked-in nonwoven materials. Requires a material having

In the second aspect, the method of the first aspect is used, but the elastic sheet is pre-stretched and fixed in both the CD and MD directions. This imparts bidirectional extensibility to the CD and MD directions to the laminate material. The laminate is heated as previously discussed.

In a third aspect, the elastic sheet layer is provided in a pre-stretched state only in the MD direction. One or more MD stretchable layers and elastic sheets are laminated to each other. The multilayer material is then preferably heated to shrink the elastic sheet in the MD direction and cause MD gathering of the MD stretchable layer. This material has good MD direction stretchability based on both the stretchable layer and the potential energy of the film.

In a fourth aspect of the invention, openings are formed in an elastic sheet layer of a multilayer material, for example an elastic film. Opening formation of the elastic film is achieved when the holes are perforated through the elastic film at spaced apart positions during the bonding step, for example, squelch bonding or ultrasonic bonding, and the facings are bonded to each other through the perforated holes of the film. do. Other opening forming techniques include hydraulic needling, pin drilling, and the like, as is known to those skilled in the art. The multilayer material produced according to the fourth aspect has the desired breathability and the desired water vapor permeability while maintaining improved stretchability. The multilayered material thus prepared can be used as side panels of personal care products, such as waistbands, and training pants and incontinence protection products.

While discussing a stretchable monolayer laminated to a pre-stretched and fixed elastic sheet layer, various aspects of the present invention provide that a pre-stretched and fixed elastic sheet layer can be incorporated to be laminated between two stretchable layers. Or one or more elastic sheet layers should be considered. In this embodiment, the multilayer “sandwich” of the elastic sheet layer and the extensible layer is stacked on each other.

The invention will be further described with reference to the following examples, which are described for purposes of illustration only. Parts and percentages shown in the examples are by weight unless otherwise specified.

Examination process

Tensile and Elongation Test

The present method for tensile strength and stretching measures the% stretching and breaking load at break of the laminate and finds the load at various tension points on the curve. This is achieved when the laminate is subjected to a continuously increasing load in a single direction at a constant rate. This test is performed on a Sintech 2 / S tester available from Syntec Corporation of Carrie Sheldon Doctor 1001, 27513, North America. The test criteria are as follows.

1. The specimen size is 2.54 cm (1 inch) wide by 15.24 cm (6 inches) long and the length is the direction to be tested for tensile strength and stretching.

2. Place each specimen longitudinally on a jaw surface of 7.62 cm (3 inches) wide and 2.54 cm (1 inch) with a jaw span of 7.62 cm (3 inches) or separation.

3. The crosshead speed is set at 30.48 cm (12.0 inches) per minute.

4. Tensile strength is to be calculated as grams per 2.54 cm (inch) of specimen width.

5. Draw in%.

6. The% tensile strength at break is 1%.

7. Break drop elongation is 0.05 cm (0.02 inch) (break drop elongation is defined as the point at which the tension has a 1% drop while the elongation goes through 0.05 cm (0.02 inch) or less).

Water vapor transmission rate (WVTR)

WVTR of the sample material was calculated according to ASTM standard E96-80. Circular samples measuring 3 inches (7.62 cm) in diameter were cut from each test material and control material, a Celgard® 2500 film piece from Hoechst Celanese Corporation, Somerville, NJ. Celgard® 2500 film is a microporous polypropylene film. Three samples were prepared for each material. The test cup is the No. 68-1 Vapometer cup from Twin-Albert Instrument Company, Philadelphia, Pennsylvania. 100 ml of water were poured into each steam pressure cup and individual samples of each test material and control material were placed over the open top of each pan. The vapor pressure cup was mechanically sealed along the edge of the cup to expose the relevant test material or control material to the ambient atmosphere on a 6.8 cm diameter circle with an exposed area of approximately 33.17 cm 2. The cup was placed in a convection oven at 37.7 ° C. (100 ° F.) for 24 hours. This oven is a constant temperature oven in which external air is circulated to prevent the accumulation of water vapor inside. After 24 hours, the pan was removed from the oven and weighed again. Preliminary test WVTR values were calculated as in the following equation (1).

(1) Test WVTR = (g weight lost over 24 hours) x (315.5 g / m 2/24 hours)

The relative humidity in the oven was not particularly adjusted. Under defined set conditions of 37.7 ° C. (100 ° F.) and ambient relative humidity, the WVTR for the Celgard® 2500 control was set at 5000 g / m 2/24 hours. Therefore, a control sample was performed with each test, and the preliminary test value was corrected according to the set conditions using the following equation (2).

(2) Standard WVTR = (Test WVTR / Control WVTR) x (5000 g / m 2/24 hours)

Example 1: Comparative Example

Lamination of Film to Conventional Spunbond:

Lamination-Exxon (R) Film EXX-601 (68.6 cm (27 inches) wide, 0.00508 cm (2 mils) thick) with conventional (non-extensible) 13.6 gsm (0.4 osy) polypropylene spunbond fabric 73.7 cm (29 Inch) width, the film was laminated so as to ultrasonically bond between two layers of spunbond fabric by ultrasonically drilling holes through the film and ultrasonically bonding the facings to each other. The width of the film at the time of lamination winding was 26 to 26.25 inches (66.04 to 66.68 cm) (66 inches to 66.58 cm (unrolled film)). Line speed was 1,219 cm / min (40 ft / min). The material was smooth on the winding rolls.

Manual test

Heat Shrink-Three test pieces 3.8 cm (1.5 inches) wide in the MD direction and 140 mm long in the CD direction were cut from a larger piece of laminate. Two marks 100 mm apart in the CD direction were placed on all samples. The sample was then heated in a 66.6 ° C. hot air circulation oven for 1.5 minutes. Next, when the distance between two marks on each test piece was measured, it was 55.0 mm, 55.0 mm, and 56.0 mm, respectively, and was an average of 55.3 mm. Subsequently, the sample was manually stretched until the tensile strength of the sample showed that the test piece was completely stretched, and the distance between the marks was measured again, and the average was 131.7 mm at 132.0 mm, 133.0 mm, and 130.0 mm, respectively. The sample was allowed to relax for 2 minutes, and then the distance between each mark was measured again, and the average was 72.0 mm, 72.0 mm, and 70.0 mm, respectively.

Theoretical stretching was 100 / 55.3 = 1.81 or 81%. The actual elongation measured manually was 131.7 / 55.3 = 2.38 or 138%.

Machine test

Samples of laminate, 45.7 cm (18 inches) with MD and 55.9 cm (22 inches) with CD, were heat activated at 66 ° C. for 3 minutes. After heat activation, the samples were measured 43.2 cm (17 inches) in MD and 34.3 cm (13.5 inches) in CD. Theoretical stretching of the heat activated laminate to CD was 22 / 13.5 = 1.63 or 63%.

Five test pieces were cut from the heat activated laminate. Each specimen was cut 2.55 cm (1 inch) wide with MD and 15.3 cm (6 inch) long with CD, the length being in the direction of stretching measurement. Each specimen was tested with the tensile and stretching tester described above. g Tensile strength and% elongation were measured for each test piece at various strain points on the curve, and the tensile failure at break (% drop = 1%) and% elongation at break (elongation at break elongation = 0.05 cm (0.02 inch)) were obtained for each test piece. It measured about the test piece. The average tensile strength and% elongation of the five specimens are shown in Table 1 below. The average elongation at break was 121%.

Breaking % Elongation 0 25 50 75 100 119 121 Tensile Strength (g / 2.54 ㎝) 0 481 705 1165 1699 1917 1909

Example 2 Lamination of Film to Necked Spunbond

Lamination-Exxon® film EXX-601 (68.6 cm (27 inches) wide, 0.00508 cm (2 mil) thick) stretched necked 22.04 gsm (0.65 osy) polypropylene spunbond fabric 71.1 cm (28 inches) The film was laminated so as to ultrasonically bond between two layers of spunbond fabric by ultrasonically drilling holes through the film and ultrasonically bonding the facings to each other. The film width at the time of laminate winding was 68.6 cm (27 inches). The pattern roll was at ambient temperature (about 21.1 ° C. (70 ° F.)). Line speed was 1,219 cm / min (40 ft / min). The material was smooth on the winding rolls. The standard WVTR of the material on the take-up roll was 938. The heat shrinked material with two facings had a useful basis weight of about 13.56 gsm (0.4 osy) to about 271.2 gsm (8 osy). The laminate of Example 2 had a basis weight of 149.2 gsm (4.40 osy).

Manual test

Heating—four test specimens, about 5.1 cm (2 inches) in the MD direction and about 140 mm in the CD direction, were cut from the larger pieces of the laminate of Example 2. Two marks 100 mm apart in the CD direction were placed on all samples. The sample was then heated in a hot air circulation oven at 65.6 ° C. for 1.5 minutes. Subsequently, the distance between the two marks on each test piece was measured again, and the average was 55.5 mm, 56.0 mm, 56.0 mm, 53.0 mm, and 57.0 mm, respectively. The sample was then drawn manually until the tension of the sample indicated that the test piece was fully stretched and the distance between the marks was measured again, with an average of 175.5 mm at 175.0 mm, 175.0 mm, 177.0 mm and 175.0 mm, respectively. The sample was allowed to relax for 2 minutes, and then again the distance between each mark was measured. The average was 92.0 mm with 90 mm, 94 mm, 89 mm and 96 mm, respectively.

Theoretical stretching based on necked spunbond with itself about 82% stretching is 182 / 55.5 = 3.28 or 228% theoretical stretching. The actual draw measured manually was 175.5 / 55.5 = 3.16 or 216% actual draw.

The difference between the actual stretch of 216% of the stretchable necked spunbond laminate of Example 2 measured manually and the% stretch 82% of the stretchable necked spunbond facing itself is 163% (([216-82] / 82) X100 = about 163%), indicating that the stretchability is substantially improved by using an elastic heat shrinkable layer.

The actual stretch difference between the stretchable necked spunbond laminate of Example 2 and the conventional non-stretch spunbond laminate of Example 1 is 56.5% (([216-138] / 138) × 100 = about 56.5%), which is stretchable. The use of necked spunbond indicates substantial stretchability.

Machine test

Samples of laminate, 45.72 cm (18 inches) with MD and 55.88 cm (22 inches) with CD, were heat activated at 65.56 ° C. for 3 minutes. After heat activation, the samples were measured 43.2 cm (17 inches) with MD and 39.4 cm (15.5 inches) with CD. The standard WVTR of this heat activated material was 827. Theoretical CD stretching based on necked spunbond with itself about 82% stretching was 40 / 15.5 = 2.58 or 158%.

Five test pieces were cut from the heat activated laminate. Each test piece was cut 2.55 cm (1 inch) wide with MD and 15.24 cm (6 inch) long with CD, and the length was in the direction of stretching measurement. Each specimen was tested with a tensile and extension tester. g Tensile strength and% elongation were measured for each specimen at various strain points on the curve, with breaking elongation at break (% drop = 1%) and% elongation at break (fall drop elongation = 0.05 cm (0.02 inch)). The average tensile strength and% elongation of the five test pieces are shown in Table 2. The average elongation at break at 1% was 188%.

Breaking % Elongation 0 25 50 75 100 125 150 175 184 188 Tensile Strength (g / 2.54 ㎝) 0 539 759 895 1117 1485 1916 2210 2289 2261

The difference between the% elongation at break of the necked spunbond laminate and the% elongation of the stretchable necked spunbond facing itself is 129% (([188-82] / 82) × 100 = about 129%), which is elastic By using the heat shrinkable layer, the stretchability is substantially improved.

The difference in average elongation at break at Example 2 between the stretchable necked spunbond laminate of Example 2 and the conventional non-extending spunbond laminate of Example 1 (comparative) was 55.4% (([188-121] / 121) × 100 = About 55.4%), indicating that the stretchability is substantially improved by using stretchable necked spunbond.

While the present invention has been described in detail with respect to particular embodiments thereof, it will be apparent to those skilled in the art that changes, modifications and other changes to the present embodiments may be made without departing from the novel teachings and advantages of the present invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined by the appended claims.

It should also be noted that all patents, applications or publications cited herein are incorporated by reference in their entirety.

Claims (27)

a) at least one first layer of extensible material; b) at least one second layer of elastic material; c) at least one second layer is laminated to at least a portion of the at least one first layer, the laminate being heat shrinked in the same axial direction as the direction in which the at least one first layer is stretched. The elastic laminate material of claim 1, wherein the elastic material is a film. The elastic laminate material of claim 1, wherein the extensible material is a nonwoven material. 4. The elastic laminate material of claim 3, wherein the nonwoven material is a spunbond material. The elastic laminate material of claim 1, wherein the at least one first layer is neck-in in the transverse direction. The elastic laminate material of claim 1, wherein the at least one first layer extends in the transverse and longitudinal directions. The elastic laminate material of claim 1, wherein the laminates have openings at spaced apart locations. 8. The elastic laminate material of claim 7, wherein the opening is achieved by a method selected from the group consisting of pin drilling, hydraulic needling, and ultrasonic bonding. The elastic laminate material of claim 1, wherein the at least one second layer is pre-stretched. a) at least one first layer of extensible material; b) at least one second layer of extensible material; c) one or more layers of elastic material; d) an elastic laminate material, wherein the elastic layer is laminated at least in part between the first layer and the second layer, and the laminate is heat shrinked in the same axis direction as the direction in which the first and second layers extend. The elastic laminate material of claim 10, wherein the coaxial elongation as measured by manual testing is about 25% to about 350% higher than the stretchable material. The elastic laminate material of claim 10, wherein the coaxial elongation as measured by manual testing is about 50% to about 300% higher than the stretchable material. The elastic laminate material of claim 10, wherein the coaxial elongation as measured by manual testing is about 100% to about 250% higher than the stretchable material. a) at least one elastic first layer comprising an opening; And b) one or more stretchable nonwoven second layers that are substantially inelastic; At least one elastic first layer is laminated to at least a portion of the at least one second layer, and the laminate is heat shrinked in the direction of the same axis as the direction in which the at least one second layer is stretched. The breathable elastic laminate material of claim 14, wherein the at least one first layer is at least one film layer. 15. The breathable elastic laminate material of claim 14, wherein the at least one first layer is a web selected from the group consisting of spunbond and meltblown materials. 15. The breathable elastic laminate material of claim 14, wherein the at least one first layer consists of a thermoplastic elastomer that can be made potentially shrinkable. 15. The breathable elastic laminate material of claim 14, wherein the at least one second layer is a web formed by a spunbond method. 15. The method of claim 14, wherein the one or more first layers a) a laminate of thermoplastic elastomers, which can potentially be made shrinkable, and b) breathable elastic laminate material comprising an adhesive. 20. The breathable elastic laminate material of claim 19, wherein the elastic body is shrunk by heating. 20. The breathable elastic laminate material of claim 19, wherein the adhesive is coextruded with the thermoplastic elastomer. 15. The breathable elastic laminate material of claim 14, wherein the basis weight is from about 13.56 gsm (0.4 osy) to about 203.4 gsm (6 osy). a) at least one elastic first layer comprising an opening; And b) at least two substantially inelastic stretchable nonwoven second layers defined as top and bottom layers, wherein an elastic layer is laminated at least in part between the top and bottom layers, the laminate being top and bottom layers The breathable elastic laminate material which is heat-shrunk in the direction of the same axis as this extending direction. The breathable elastic laminate material of claim 23, having a basis weight of about 13.56 gsm (0.4 osy) to about 271.2 gsm (8 osy). a) providing at least one first polymer; b) forming at least one first polymer into a first nonwoven web; c) stretching the first nonwoven web to neck the first nonwoven web in a transverse direction; d) providing a second polymer; e) forming a second polymer into a second nonwoven web; f) stretching the second web to neck the second nonwoven web in a transverse direction; g) providing one or more layers of elastic material that are heat shrink in the transverse direction; h) adhering at least one layer of elastic material between the stretched first web and the stretched second web at a selected location to form a laminate; And i) heating the laminate of step h) to shrink the elastic material. The method of claim 25 further comprising forming an opening at least partially through the laminate. The method of claim 25, wherein the heating step is performed at about 65.5 ° C. (150 ° F.) for about 1.5 minutes.