KR100609375B1 - Breathable Composite Elastic Material Having a Cellular Elastomeric Film Layer and Method of Making Same - Google Patents

Abstract

Materials and methods are provided for providing a stack of two or more layers to provide breathable and moisture barrier properties without significantly reducing elastic properties. The first material comprises a woven or nonwoven web and the second material comprises a cellular elastomeric film or fiber. These materials can be integrated into a stack by forming the first material on the second material or by combining the two materials through chemical or physical means such as the use of an adhesive. The second material can be prepared by mixing the cell opener and the elastomeric resin and extruding the mixture under suitable conditions such that the cell opener decomposes or reacts to release the gas that forms the cell in the elastomeric film. This material is useful for personal care products where desirable properties such as comfort, body shaping, consistency, dryness, such as diapers, feminine hygiene products, child care products, incontinence products, and health care products.

Elastic, Breathable, Water Resistant, Cellular Elastomer, Cell Opener

Description

Breathable Composite Elastic Material Having a Cellular Elastomeric Film Layer and Method of Making Same             

[Cross Reference of Related Application]

This application claims priority to co-pending US provisional patent application Ser. No. 60 / 113,908, filed Dec. 28, 1998 and commonly assigned to the assignee of the present invention, the disclosures of which are incorporated herein by reference. The entirety of which is incorporated herein by reference.

The present invention relates to a breathable elastomeric film comprising at least one layer of woven or nonwoven material and at least one layer of elastomeric film or fibrous material in which cells are opened and / or closed therein by cell openers; A laminated material is related.

Materials having the desired degree of breathability and moisture barrier properties are useful in personal care products that aim to contain fluids in the product structure while allowing for the exchange of outside air, such as diapers, incontinence products, and feminine hygiene products. The traditional method of providing such materials is to introduce an outer cover having a microporous structure that can maintain liquid barrier properties. These materials typically include laminates or composites of film layers and elastic layers (usually made of nonwoven materials). Traditionally, film layers have been made of polyolefin or polyurethane materials. However, such materials have been limited because they do not provide the proper elastic and breathable properties needed for personal care products. Recently, extensible polyolefins have been developed but these materials have limited elasticity.

Aperturing polyolefins or similar materials can be accomplished by mechanical or other force application techniques. Mechanical perforation tends to make holes with rugged edges, while blowing agents tend to make smoother holes. Smoother holes have less stress points on the film, making them stronger and more resistant to tearing than edged holes. Mechanical perforation of the polyolefin is possible because the film formed therefrom has sufficient stiffness to prevent substantial deformation of the sheet as pins or other puncturing forces pass through it. In the case of materials such as elastomers, which form sheets with greater flexibility than polyolefins, the material is excessively deformed during drilling to produce holes or materials with moderate mechanical properties with poor quality and definition. Mechanical perforation has become a problem.

Breathability can also be obtained by forming holes or cells in the film. One way to achieve this is to introduce particles of a material such as calcium carbonate into the extrusion mix. The extruded film forms or encapsulates cells or pockets around the particles. Once the film is stretched, the pockets are stretched to form pores and / or microtherms, through which air can pass. The problem with this technique is that the hole definition can be poor because the stress is introduced into the pore area, and if the shape of the particles is irregular the shape of the formed pores can be irregular and the strength can be reduced by tearing. This technique may be unavailable to form pores in materials such as certain elastomers. Even if the pores are formed regularly in this material, if the bias force or stress is removed, the pores will probably crash or close due to shrinkage of the polymer.

Elastomers are preferred materials for use in personal care products because of their stretching and recovery properties as compared to polyolefins with improved shaping, conformability, and potentially improved functionality. However, the introduction of holes or openings in the form of voids or hot poles in the elastomer has been a problem because it is difficult to retain the porous structure due to the relaxation of the elastomer. It would be desirable to have a process that would provide a predictable thermode definition without forming the thermode in the elastomer and significantly increasing the manufacturing cost. It would also be desirable for such a drilling process to allow adjustment of the size of the hole, the distribution of the hole and other related properties as a function of stretching or stretching.

It is therefore an object of the present invention to provide a cellular elastomeric composite material that provides a moderate degree of breathability, fluid barrier properties and elasticity, suitable for use in personal care products.

It is another object of the present invention to provide a method of forming a cellular elastomeric film composite having predictable pore definition, pore distribution and acceptable mechanical properties.

It is a further object of the present invention to add a cell opener to at least one layer of woven or nonwoven material, and an elastomer and to extrude the mixture so that the cell opener forms open and / or closed cells in the film produced from the elastomer. It is to provide a composite laminate material comprising a layer of cellular elastomeric film or fibrous material having the resulting voids.

It is another object of the present invention to provide a material having a breathable film layer suitable for use as a stretchable top sheet for use in the management of body fluids such as menstruation, blood, urine and flowable bowel movements.

Summary of the Invention

The present invention provides materials and methods for forming a stack of two or more layers that provide breathability and moisture barrier properties without significantly reducing elastic properties. The first material comprises a woven or nonwoven web and the second material comprises an elastomeric film or fiber. Such materials may be integrated into the stack by forming the first material on the second material or by combining the two materials through chemical or physical means such as the use of an adhesive. The second material can be prepared by mixing the cell opener with the elastomeric resin and extruding the mixture under suitable conditions to cause the cell opener to decompose to release gasses that form open and / or closed cells in the elastomeric film. have. This material is useful for personal hygiene products such as diapers, feminine hygiene products, child hygiene products, incontinence products and health care products where such properties are desirable for properties such as comfort, body shaping, consistency, dryness and the like.

According to the method of the invention, the elastomeric material is mixed with the cell opener. The mixture is extruded through a film extrusion die to form a sheet. Alternatively, the filament-forming die may be used to form the filament. During the extrusion process, the cell opener decomposes or otherwise reacts physically or chemically to release the expanded volume of gas or other material from the form before the original extrusion. The gas forms openings or cells in the softened elastomeric material. The extruded elastomeric material thus has a plurality of open and / or closed cells formed therein, and in the case of open or partially open cells, can carry air or fluid therethrough. The elastomeric material formed may be laminated to other woven or nonwoven surfaces by known methods to produce a laminate material having desirable breathable and elastic properties.

Lamination of the present invention is intended for personal hygiene products such as, but not limited to, bandages, wound dressings, diapers, training pants, protective swim underwear for children, incontinence, panty shields or linings, or sweating shields. Can be used for formation. Lamination can also be used to form disposable protective apparels, such as but not limited to surgical gowns or industrial workwear.

[Justice]

As used herein, the term "nonwoven" fabric or web refers to a web having the structure of individual fibers or yarns interlaid in a form other than a regularly repeated pattern, such as in a reticular or knitted fabric. Nonwoven fabrics or webs may be used, for example, such as meltblown, spunbond, hydroentanglement, air-laid, bonded carded webs and other processes. It has been formed by various processes.

As used herein, the term "spunbond fiber" is a small diameter fiber of polymeric material, which may or may not be molecularly oriented. Spunbond fibers are obtained by extruding molten thermoplastic material as filaments from a plurality of fine, typically circular capillaries of spinneret having a diameter of the filament being extruded, and then, for example, US Pat. No. 4,340,563 to Appel et al. And US Pat. Nos. 3,692,618 to Dorschner et al., US Pat. Nos. 3,802,817 to Matsuki et al., US Pat. It can be formed by rapid reduction as described in US Pat. No. 3,542,615 to Hobo, Dobo et al. And US Pat. No. 5,382,400 to Pike et al. Spunbond fibers are generally non-sticky and generally continuous when deposited onto a collecting surface. Spunbond fibers are usually at least about 10 microns in diameter. However, microfiber spunbonds have been filed on Nov. 26, 1996, and are now filed on April 30, 1998, co-pending US patent application Ser. No. 08 / 756,426 and Pike et al. It may be obtained by a variety of methods, including but not limited to the method described in Patent No. 5,759,926.

As disclosed herein, the term “meltblown fibers” is intended to extrude molten thermoplastic or thermosetting (ie, crosslinkable samples or post-crosslinkable polymers) through a number of fine, usually circular die capillaries. Refers to fibers of polymeric material, which are generally formed by passing an elastic material as molten yarn or filament and passing it through a high speed, usually hot, gas (eg air) stream that thins the filaments of the molten thermoplastic and reduces its diameter do. The meltblown fibers can then be carried in a high velocity gas stream and deposited on a collecting surface to form a web of randomly dispersed meltblown fibers, which can include microfiber webs. Such a process is disclosed, for example, in US Pat. No. 3,849,241 to Butin et al. Meltblown fibers can be continuous or discontinuous and are generally sticky when deposited on a collecting surface.

As used herein, the term "conjugate fibers" refers to fibers formed from two or more polymers that are extruded from separate extruders but spun together to form one fiber. Conjugate fibers are also sometimes referred to as multicomponent or bicomponent fibers. Although the conjugate fibers may be monocomponent fibers, the polymers are usually different from one another. The polymer is arranged in separate zones located substantially continuously beyond the cross section of the conjugate fiber and extends continuously along the length of the conjugate fiber. The structure of such conjugate fibers can be, for example, a sheath / core arrangement in which one polymer is surrounded by another, or a side by side arrangement or " island-in- the-sea) "array. Conjugate fibers are taught in US Pat. No. 5,108,820 to Kaneko et al., US Pat. No. 5,336,552 to Strack et al. And US Pat. No. 5,382,400 to Pike et al. For bicomponent fibers, the polymer may be present at 75/25, 50/50, 25/75 or any other desired ratio.

As used herein, the term "polymer" generally includes but is not limited to homopolymers, copolymers (e.g., blocks, grafts, random and alternating copolymers, terpolymers, etc.), and combinations and variations thereof. It is not limited. In addition, unless specifically limited otherwise, the term "polymer" includes all possible steric structures of the molecule. These structures include but are not limited to isotactic, syndiotactic, and any symmetry.

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

As used herein, the term "extensible" means stretchable or stretchable in more than one direction.

As used herein, the term "recovery" means that the stretched material contracts when the biasing force is applied to increase the material and then the biasing force is removed. For example, if a relaxed and unbiased length (L ₀ ) of 1 inch (2.54 cm) is stretched to a length of 1.5 inches (3.81 cm), the material will have an elongation of 150% (L * 100 / L ₀ = 1.5 * 100/1), where elongation is defined as elongated (L) divided by unbiased length (L ₀ ). If the stretched material in this example is retracted, ie 1.1 inches (2.79 cm) after releasing the bias and stretching forces, the material has recovered 80% (0.3 inches, 1.02 cm) of its elongation.

As used herein, the term "elastic" can be stretched to a bias length that is at least 200% of the relaxed and unbiased length by applying a biasing force, i.e. extendable, at least 75% of the elongation upon releasing the stretching force. Means a material that shrinks. A hypothetical example would be a sample of material that is originally 1 inch (2.54 cm) in length that is stretched at least 2.0 inches (5.08 cm) and contracted to at least 1.75 inches (4.45 cm) without removing the biasing force. Not shrink to 1 inch (2.54 cm) in length.

As used herein, the term "inelastic" or "inelastic" refers to any material that does not fall within the definition of "elastic".

As used herein, the term "personal hygiene" means a product or product, or component of a product or product, that absorbs fluids or semi-fluids, such as body secretions, but where breathability and air exchange are important. Such products include, but are not limited to, diapers, training pants, absorbent articles, adult incontinence products, feminine hygiene products, bandages, dressings, and similar performance products.

As used herein, terms including "aperture", "cell", "pore", hole and "micropore" and forms thereof Used interchangeably, it generally refers to an opening at least partially inside the structure, such as, but not limited to, a sheet of material. The opening may extend from the surface inward or from one surface to the other surface completely (ie an open cell), or the opening may be completely inside the structure (ie a closed cell that is not open to the exterior surface). . The path or shape of the thermode may be a straight, curved shape, curved, generally circular, oblong, spherical, interwined, interconnected or any other shape or relationship of shapes. See FIG. 1.

As used herein, the term "layer" generally refers to a single piece or sheet of material, although the same term refers to multiple sheets or plies of material that together form one or more "layers" of this specification. It should also be thought of as meaning.

As used herein, the term "stretch bonded" refers to an elastic member that is joined to another member while the elastic member is stretched to at least about 25% of its relaxation length.

As used herein, the term "stretch bonded laminates" refers to a composite material having two or more layers, one of which is a gatherable layer and the other is an elastic layer. it means. When the elastic layer is in the stretched condition, the layers are joined together to pleat the crimpable layer by relaxing the layers. Such multiple composite elastic materials can be stretched to such an extent that the nonelastic material pleated between the bonding locations causes the elastic material to stretch. One type of stretch bonded laminate is disclosed, for example, in US Pat. No. 4,720,415 to Vander Wielen et al., Which uses multiple layers of the same elastomer produced from multiple banks of extruders. . Other composite elastomeric materials include U.S. Patent 4,789,699 to Kieffer, U.S. Patent 4,781,966 to Taylor, U.S. Patent 4,657,802 and 4,652,487 to Morman, and U.S. Patent 4,655,760 to Morman. It is disclosed in the call.

As used herein, the term "neck bonded" refers to an elastic member that is coupled to an inelastic member while the inelastic material extends in one direction and necked in a perpendicular direction.

As used herein, the term "neck bonded lamination" refers to a composite material having two or more layers, one layer being a necked inelastic layer and the other layer being an elastic layer. The layers are joined together when the inelastic layer is necked. Examples of neck-bonded laminates are those as disclosed in US Pat. Nos. 5,226,992, 4,981,747, 4,965,122, and 5,336,545 to Mormon.

As used herein, "air-permeable (breathable)" term is a minimum water vapor transmission rate (WVTR) is the point on the permeable material of about 300 g / m ^2/24 sigan water vapor. The WVTR of the fabric, in one aspect, provides an indication of how comfortable the fabric is when it is worn. WVTR is measured as described in the following Examples the results were reported as g / m ^2/24 hours. However, often applications of breathable barriers has a preferably higher WVTR measurements, air-permeable barrier of the present invention is 500 g / m ^2/24 sigan, 800 g / m ^2/24 sigan, 1500 g / m ^2/24 time-out, and even it may have a WVTR measurements exceeding 20,000 g / m ^2/24 hours.

Detailed Description of the Preferred Embodiments

The present invention provides a breathable elastomeric laminate material comprising at least one layer of woven or nonwoven material and at least one layer of cellular elastomeric film or cellular fibrous material. If desired, an additional extensible layer may be attached to the stack, for example, as a second extensible fibrous woven or nonwoven facing layer on the surface of the elastic film layer opposite the extendable facing layer. The film layer was processed to form a hot electrode or cell using a novel method as described below.

The film layer is composed of elastic resin. Useful elastomeric resins are thermoplastic polymer endblocks containing styrene moieties such as general formula ABA 'or AB, where A and A' are each poly (vinyl arene), and B is an elastic, such as conjugated diene or lower alkene polymer. Polymers or rubber polymer midblocks), including but not limited to block copolymers. Block copolymers of the ABA 'type may have the same or different thermoplastic block polymers as the A and A' blocks, and the present block copolymers are intended to include linear, branched and radial block copolymers. In this respect, 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 radially spread out of X in such a way that A is 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 and is often not limited to 4 or 5 but only. Thus, in the present invention, the expression "block copolymer" and in particular the expressions ABA 'and AB block copolymer are intended to include all block copolymers having rubber blocks and thermoplastic blocks that can be extruded as described above and are block There is no limit to the number of. The polymer may for example be formed from an elastomeric polystyrene / poly (ethylene-butylene) / polystyrene block copolymer. Commercial examples of such elastomeric copolymers are those known under the trademark KRATON material, for example, available from Shell Chemical Company, Houston, Texas. Trademark Creighton block copolymers are available in several different formulations, some of which are identified in US Pat. Nos. 4,663,220 and 5,304,599. In addition, unsaturated polymers such as, but not limited to, styrene-butadiene-styrene (SBS), styrene-isoprene-styrene (SIS), and the like may also be used.

Polymers composed of elastomeric A-B-A-B tetrablock copolymers may also be used as elastic layers 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 hydrogenated to a poly (ethylene-propylene) monomer unit. Examples of such tetrablock copolymers are SEPSEP elastomeric block copolymers available under the trade names styrene-poly (ethylene-propylene) -styrene-poly (ethylene-propylene) or Creighton.

Other exemplary elastomeric materials that may be used are, for example, those available under the trademark ESTANE from BFGoodrich & Co. or Morton Thiocol Corp. Polyurethanes (such as-(AB) _-n , where A is a hard block and B is a rubber block) such as those available under the trademark MORTHANE from Morton Thiokol Corp. For example Delaware Wilmington. Available under the trademark HYTREL from EI du Pont de Nemours & Company and formerly from Akzo Plastics, Arnhem, The Netherlands and now the Netherlands Polyetherester elastomeric materials such as those available under the trademark ARNITEL, available from DSM, Sittard.

The thermoplastic copolyetherester elastomer includes a ester in the copolyether of the following general formula.

Wherein "G" is selected from the group consisting of poly (oxyethylene) -alpha, omega-diol, poly (oxypropylene) -alpha, omega-diol, poly (oxytetra-methylene) -alpha, omega-diol, "a" and "b" are positive integers including 2, 4 and 6, and "m" and "n" are positive integers including 1-20. Such materials generally have a break point elongation of about 600% to 750% as measured according to ASTM D-638 and a melting point of about 350 ° F to about 400 ° F (176 to 205 ° C) as measured according to ASTM D-2117. Has Another suitable material is a polyetherester block amide copolymer having the formula

Wherein n is a positive integer, PA represents a polyamide polymer segment and PE represents a polyether polymer segment. In particular, the polyether block amide copolymers have a melting point of about 150 ° C. to about 170 ° C. as measured according to ASTM D-789; A melt index of about 6 g / 10 minutes to about 25 g / 10 minutes as measured according to ASTM D-1238, Condition Q (235 ° C./1 Kg load); Flexural elastic modules from about 20 MPa to about 200 MPa as measured according to ASTM D-790; Break tensile strength of about 29 MPa to about 33 MPa as measured according to ASTM D-638; And an ultimate wave disadvantage elongation of from about 500% to about 700% as measured according to ASTM D-638. Specific embodiments of the polyether block amide copolymers have a melting point of about 152 ° C. as measured according to ASTM D-789; A melt index of about 7 g / 10 minutes as measured according to ASTM D-1238, Condition Q (235 ° C./1 Kg load); Flexural elastic module of about 29.50 MPa as measured according to ASTM D-790; Tensile strength at break of about 29 MPa as measured according to ASTM D-639; And an elongation at break of about 650% as measured according to ASTM D-638. Such materials are available in various grades under the trade name PREBAX from ELF Atochem Inc. of Philadelphia, Pennsylvania. Examples of the use of such polymers can be found in US Pat. Nos. 4,724,184, 4,820,572 and 4,923,742, assigned to the same person as the assignee of the present invention as a patent of Killian et al.

Elastomers also include copolymers of ethylene and one or more vinyl monomers (eg vinyl acetate, unsaturated aliphatic monocarboxylic acids and esters of such monocarboxylic acids). Elastomer copolymers and the formation of elastomeric nonwoven webs from such elastomeric copolymers are disclosed, for example, in US Pat. No. 4,803,117.

The nonwoven layer is preferably formed by a spunbond or meltblown process, but includes water flow agglomeration, airlaid, bonded carded webs, flocced structures, needlepunched webs, spunlaces and the like. Other processes are possible, including but not limited to. Spunbond materials include polyolefins selected from the group consisting of polypropylene, polyethylene, and copolymers of propylene and ethylene suitable for spunbond processing. Preferred polypropylene is the trademark Exxon PD 3445 polypropylene (hereinafter sometimes referred to as "PP") available from Exxon Chemical Company, Houston, Texas. The trademarked Exon PD 3445 is typically available for meltblown applications such as the trademarked Monttell PF 015 polypropylene (sometimes referred to herein as Trademark Monte PD 015), which is available from Montel Chemical, Wilmington, Delaware. It has also been found that the combination of low viscosity polypropylene used with the trademark Exon PD 3445 in the range of about 50-100%, more preferably about 66%, provides an acceptable mix. It was found that 100% exon PD 3445 yielded higher quality results than using a blend of polypropylene resins with a narrow molecular weight distribution and low melt viscosity. For example, the melt flow rate (at 230 ° C.) is greater than about 35 g / 10 minutes. However, it should be understood that such combinations may be used for specific purposes. When copolymers of propylene and ethylene are used, the ethylene content is present with at least about 93% propylene at concentrations of up to about 7%. It will be appreciated that bicomponent, multicomponent and multiconstituent fibers may be used in the present invention. The nonfilm layer may also be a woven or knitted material. Other suitable elastomers can also be used to make thermoplastic elastomer filaments. These include, but are not limited to, elastomeric (single-site or metallocene catalyzed) polypropylene, polyethylene and other alpha-olefin homopolymers and copolymers (density less than about 0.89 g / cc); Ethylene vinyl acetate copolymers; And substantially amorphous copolymers and terpolymers of ethylene-propylene, butene-propylene and ethylene-propylene-butene.

Single-site catalyzed elastomers (eg, constrained geometry or metallocene-catalyzed elastomers) are relatively new and are currently preferred. The single-site process for preparing polyolefins uses a single-site catalyst that is activated (ie, ionized) by a co-catalyst.

Polymers produced using single-site catalysts have a narrow molecular weight distribution. "Narrow molecular weight distribution polymer" refers to a polymer exhibiting a molecular weight distribution of less than about 3.5. As is known in the art, the molecular weight distribution of a polymer is the ratio of the weight average molecular weight of the polymer to the number average molecular weight of the polymer. Methods for determining the molecular weight distribution are described in Encyclopedia of Polymer Science and Engineering, Volume 3, pages 299-300 (1985). Polydispersity (M _w / M _n ) of less than 3.5 and even less than 2 is possible for single-site produced polymers. These polymers have a narrow short chain branching distribution as compared to polymers similar to that produced by Ziegler-Natta.

When using stereo selective metallocene catalysts, it is also possible to control the isotacticity of the polymer very closely using a single-site catalyst system. Indeed, polymers with isotactic degrees of greater than 99% have been produced. It is also possible to produce highly syndiotactic polypropylene using this system.

Commercial production of single-site catalyzed polymers is somewhat limited but growing. Such polymers are purchased from Exxon Chemical Company, Baytown, Texas, under the registered trademark of EXXPOLL for polypropylene-based polymers and under the registered trademark of EXACT for polyethylene-based polymers. It is possible. Dow Chemical Company, Midland, Mich., Has a polymer commercially available under the trademark ENGAGE. These materials are thought to be produced using non-stereo selective single-site catalysts. Exxon refers to their single-site catalyst technology as a metallocene catalyst, while Dow refers to their technology as a "rigid geometric" catalyst under the trade name Trademark, INSIGHT, with a traditional Ziegler-Natta catalyst with multiple reaction sites. Separate. Other manufacturers such as Fina Oil, BASF, Amoco, Hoechst and Mobil are active in this field and the availability of polymers produced according to this technology is: It is expected to grow substantially in 10 years.

Regarding single-site catalyzed elastomers, US Pat. No. 5,204,429 to Kaminsky et al. Discloses cycloolefins and linear olefins using aluminoxanes and catalysts, which are stereorigid chiral metallocene transition metal compounds. From a process for producing an elastomeric copolymer. The polymerization is carried out in an inert solvent such as aliphatic or cycloaliphatic hydrocarbons (eg toluene). The reaction can also take place in the gas phase using the monomer to be polymerized as a solvent. Lai et al., US Pat. Nos. 5,278,272 and 5,272,236, assigned to Dow Chemical and entitled "Substantially Linear Elastic Olefin Polymers," describe polymers with specific elastic properties. Dow also commercially produces a series of elastomeric polyolefins under the trade name ENGAGE.

In a preferred embodiment, the cellular film or fibrous woven or nonwoven material of the present invention is produced from a polymeric resin. Typically, the resin is provided in particle form, ie as a powder, granules or pellets. Other properties can be controlled by mixing other materials with the resin, for example, by mixing a tackifier to increase the bonding capacity of the extruded film, or by mixing other components to provide processability or by suitable chemical or physical The reagents can be mixed to provide blowing by in situ chemical reactions during decomposition, evaporation or processing. The resin may also contain other additives that can alter thermal and other material properties.

The cell opener (also referred to as foaming agent) may be any material that produces a gas that, in the broadest sense, is preferably (but not forcibly) inert when exposed to a film forming process (eg extrusion). have. The gas forms openings in the film. The cell opener may be azodicarbonamides such as Celogen AZN 130 from Uniroyal Chemical Company, Inc., Connecticut, Middlebury. The trademark Celogen product line is a group of chemicals. For further explanation of this material, reference may be made to "Celogen Blowing Agent," R.L.Heck, III and W.J.Peascoe, Encyclopedia of Polymer Science and Engineering, Vol. 2, 2nd Ed., P.434 et al. The cell opener may be a fluorocarbon. Additional types of cell openers are low boiling solvents (eg methylene chloride) and water, which produce steam at temperatures in a die extruder. Trademark cellogens are typically provided as dispersions or powders. The cell opener may be provided as a solid, gas, liquid, gel, foam, semi-solid, slurry or other form, depending on the specific properties of the specific cell opener and the material properties desired as the end object.

In other embodiments, the cell opener may be selected or modified to produce an active gas (or fluid, solid, particulate or other material) that may be trapped in the cell within the elastomeric material during mixing and / or extrusion. The elastomeric film material may be selected to cause the gas to be released into the environment over which the gas is active and may act on the substrate or other material over a delayed period of time. High concentrations of carbon dioxide have been shown to have an inhibitory effect on the formation of yeast filaments causing diaper rash. Other yeasts, molds, bacteria or undesirable microorganisms can be prevented by releasing suitable inhibitory substances in gaseous or vapor form from the cells of the film laminated to the stretchable material.

Returning to the general discussion of the cell opener, the polymer resin and the cell opener are mixed and heated to form a molten resin and conveyed to the extruder die inlet port by an extruder screw. The die is typically heated and the molten resin mixture is extruded or spun into film sheets or into filaments, fibers or strands by extrusion methods known in the art. Extruded films can be produced through a number of processes, such as casting, blowing, and the like. The cell opener is preferably decomposed in response to elevated temperatures such as those experienced before, during and / or after the resin exits the film extrusion die head. Specific cell openers may include, but are not limited to, pH, pressure, light (e.g., ultraviolet, infrared), microwave energy, vibrational energy, other types of electronic energy, nuclear energy (e.g., explosions), etc. It is possible to release gases under other process conditions. The gas is at least partially trapped in the molten material as it is released or produced. When the gas is completely trapped by the film, an unopened cell is formed on the outer surface of the material.

In a broad aspect of the invention, the cell opener may undergo certain types of changes, one of which is decomposition. Changes can be phase transitions, decomposition, degradation, other chemical reactions, physical changes (eg, volume increase caused by reduced pressure or elevated temperature), energy changes, and the like. In a sense, the polymer phase transition corresponds to the phase transition of the cell opener selected for the particular situation. It will be appreciated that these and other structural, chemical and physical changes are known to those skilled in the art and need not be described in detail herein.

1 is a schematic of various types of cells and openings that may be formed in an elastomeric material 5 laminated to a facing material layer 10. If the gas forms a cell 12 or 14 extending toward each of the surfaces 16 or 18, an opening 20 or 22 is formed in the surface of the film. The opening 24 extends from one surface 4 through the elastomeric material 5 to the other surface 6. In addition, the cells may be discontinuous, such as in cells 26 or interconnected cells 28 that are entirely within the polymeric material 5. Other more complex shapes and geometries are possible and are considered to be within the scope of the present invention.

It is a feature of the present invention that by manipulating the cell opener it is possible to control the quantity and quality of the formed thermode. Most advantageously, the size and distribution of the thermode may be adjusted by selection of cell openers and concentrations to provide optimal breathability of the film layer for a given composite material. Other properties that can be controlled include, but are not limited to, the opening or closing of the thermode, interconnectivity, shape, density, and the like. Breathability is enhanced by thermodes extending completely through the layer and exposed to the surfaces on both sides.

It is also contemplated by the present invention that the polymer resin and cell opener mixtures are formed into filaments by extrusion, meltblowing or otherwise, in which gas forms pores or microcellular thermodes in the filaments.

The thermode formed in the elastomeric film by this process has a smoother shape than that formed by conventional mechanical drilling because puncturing or rupturing of the film usually does not occur. However, smooth bubbles are formed in the molten or partially solidified film structure. Such smooth hot poles have few stress points and are more resistant to tearing, resulting in materials having a stronger and higher linear elastic range due to greater structural and polymer elasticity. Additional advantages of the film layer materials produced by the present invention include low density, cost savings, improved breathability and higher WVTR and greater MD and CD extensibility. An additional advantage of pore cellular materials or composites thereof is that they can otherwise introduce increased opacity to transparent materials. The advantage for this material is improved taste and discretion. More particularly, the appearance of stains such as those associated with feminine hygiene products and infant, infant and adult hygiene products can be substantially reduced.

In addition, the perforated film layer can be produced at a faster rate than by vacuum or pin perforation because no additional step of mechanical perforation is required in the present invention. When used as side panels in training pants and related articles, when the pants are removed, the material exhibits a reduced snap back of the elastomer during tearing of the side panels after use.

Alternatively, openings in the material can be formed by reaction of a suitable reagent that releases small molecules during in-situ formation. These small molecules must be stripped from the material during which they form porous passages. One example is the reaction product of isocyanates with polyols and water, which produces carbon dioxide as described in more detail below. Hollow cellular fiber elastomers can be used as further cost savings or improvements with performance and breathability similar to current elastomers.

In another embodiment of the present invention, the inner surface of the formed cell or opening may be coated with a material. Such materials, such as, but not limited to, pH indicators, dyes, liquid crystals, etc., provide color or other changes in response to temperature, acidity / alkalinity, gas evolution, or other changes that occur during normal use of the product. It may be an indicator substance. Such materials are useful in determining when they get wet or dirty without irritating or smelling them, without overexposing, especially in diapers. In another embodiment, for a closed cellular elastomeric material, a drug, pharmaceutical, medicament or other material provided in solid, semi-solid, liquid, particulate or other form is encapsulated in a cell in the elastomeric material and released over time can do. Such materials can be used in bandages or other wound dressings, transdermal delivery tools, and the like.

The cellular material of the present invention may be laminated by techniques known to those skilled in the art or otherwise coupled to one or more additional layers of the same material as said material.

For purposes of illustration (but not limitation), a process such as shown schematically in FIG. 2 is for the formation of a neck bonded laminate that incorporates the elastomeric material of the present invention. In this process the first neckable material 102 is released from the feed roll 104. The neckable material 102 then moves in the direction indicated by the associated arrow as the feed roll 104 rotates in the direction of the associated arrow. The neckable material 102 then passes through the fins 106 of the S-roll arrangement 108 formed by the stack rollers 110 and 112. The neckable material 102 may be formed by a nonwoven extrusion process, such as, for example, a spunbonding or meltblowing process, which then removes the fin 106 of the S-roll arrangement 108 without first being stored on a feed roll. Pass directly through.

The neckable material 102 then passes through the fin 106 of the S-roll arrangement 108 in the reverse S-wrap path represented by the direction of rotation arrow associated with the stack rolls 110 and 112. Since the peripheral linear velocity of the rollers of the S-roll arrangement 108 is adjusted to be lower than the peripheral linear speeds of the rollers of the bonder rollers 144 and 145, the neckable material 102 is tensioned to neck the desired amount and to elastic As the sheet 132 is formed directly on the inelastic material, it remains in this tensioned and necked state.

As the necked material 102 passes past the conventional meltblown process arrangement 122, an elastic sheet 132 of the meltblown fibers 120 is formed directly on the necked material 102. The meltblown fibers 120 may include meltblown microfibers. Orienting the stream of elastomeric meltblown fibers 120 at high speed onto the necked material 102 from the meltblown processing apparatus 122 while the fibers are soft to deposit the deposited elastomer of the meltblown fibers 132. Bonding and / or entanglement occurs between the sheet and the necked material 102.

In general, when the fibers have a high initial speed, for example from about 300 feet (9144 cm) / second to about 1000 feet (30,480 cm) / second, the meltblown fibers 120 are suited to the necked material. Combined. Additionally, the vertical distance from the forming nozzle 124 of the meltblowing process apparatus to the necked material can range from about 4 to about 18 inches (10.16-45.72 cm). For example, the vertical distance can be set to about 12 inches (30.48 cm). The elastic sheet 132 may also be formed by other known extrusion processes.

In a preferred embodiment, the film extrusion device 133 produces a sheet of cellular elastomeric film 134. Initially, the polymer mixture is heated into the molten resin mixture while mixing the elastomer with the cell opener and introducing into the screw conveyor 135. The mixture is conveyed to a film extrusion die 136 where it is extruded into a film sheet 134. The elastomeric film 134 is then passed between the fin arrays 137 comprising rollers 138 and 139. Elastomer film 134 is passed through rollers 140, 141 and 142 (or other numbers or arrangements). Passing the elastomeric film 134 to the elastic sheet 132 by passing two sheets through the array 143 including bonding rollers 144 and 145 (either or both of which may be heated or nothing heated). )). The laminated material 146 is relaxed and then wound around the take-up roll 147 for storage or further processing.

In another embodiment of the neck bonded lamination process of the present invention, the second neckable material 150 is unrolled from the feed roll 152 as in FIG. The neckable material 150 is then moved in the direction indicated by the arrow associated therewith and the feed roll 152 is rotated in the direction of the arrow associated therewith. The neckable material 150 is then passed through the fins 154 of the S-roll arrangement 156 formed by the stack rollers 158 and 160. Alternatively, the neckable material 150 may be formed by a known nonwoven extrusion process, such as, for example, known spunbonding or known meltblowing processes, which are then not stored on feed roll 152 first. Without passing directly through the fin 154 of the S-roll arrangement 156.

The neckable material 150 passes through the fin 154 of the S-roll arrangement 156 in the reverse S-wrap path indicated by the rotational arrows associated with the stack rollers 158 and 160. Since the peripheral linear velocity of the rollers of the S-roll array 156 is adjusted to be smaller than the peripheral linear velocity of the rollers of the bond roll array 143, the neckable material 150 is tensioned to neck the desired amount, and the elastic sheet ( 132, and thus remain tensioned and necked upon being covered on the necked material 102 and the elastomeric sheet 134. Four layers pass through the jaws of the bonder roller arrangement 143 to produce the composite elastic necked bonded material 170, which is relaxed and wound on the wind-up roll 172. The bonder roll arrangement 143 may be a patterned calender roller arranged with a smooth anvil roller. Alternatively, a smooth calender roller can be used. One or both of the calender roller and the anvil roller can be heated and the pressure between these two rollers can be adjusted in a known manner to provide the desired temperature and bonding pressure. For example, other methods such as adhesives, ultrasonic welding, laser beams, and / or high energy electron beams can be used to bond the layers. The bond surface area on the composite elastic necked bonded laminate can approach about 100% and also provide a material with predictable elongation properties.

The elastomeric film of the present invention may also be used in the process of forming a composite elastic material containing at least one anisotropic elastic fibrous web and at least one crimpable layer bonded at spaced locations. Such materials are disclosed in US Pat. No. 5,385,775 to Wright. Wright's patent simply states that an elastomeric filament layer 200 is extruded from a polymer resin conveyed through a extruder 203 to a continuous filament extrusion die 202, and is an endless belt typically driven by rollers 206 and 208. A process as shown in FIG. 4 is disclosed that is deposited on the phosphorus porous collection surface 204. Elastomeric filament 200 is deposited in a substantially parallel alignment on the belt 204 surface, and the belt rotates in the direction of the arrow. The cell opener can be added to the extrusion mix and then shipped to the extrusion die 202 in accordance with the present invention. Elastomer filament 200 will contain a cell when extruded. Meltblown fibers 210 are formed by meltblown die apparatus 212 and deposited on elastomeric filaments 200. 닢 array comprising rollers 214 and 216 under pressure (and temperature, if desired) to cause permanent autogenous bonding between elastomeric filament 200 and elastomeric meltblown fiber 210. The two layers can be calendared by passing the layers through. Details regarding this process are disclosed in US Pat. No. 5,385,775 to Wright. One or more layers of the bonded laminate product 220 of this process may, in turn, be laminated to one or more layers of the elastomeric material of the present invention to form a composite structure. The resulting laminated composite material exhibits desirable elastic properties as well as breathability and barrier properties of materials known in the art using polyolefins, but with stretch properties of elastomeric materials.

Conventional drive means and other conventional devices usable with the device are well known to those skilled in the art and are not illustrated for clarity.

The cellular elastomeric film or fibrous nonwoven or woven material may be stretchable in the transverse or machine direction and then laminated to a second material such as a film, foam, fabric, nonwoven, or the like. After lamination, the elastic material will shrink to allow the material to corrugate and form a microscopic or macroscopic structure. The extent to which this occurs is a direct function of the material properties of each layer and bonding pattern.

The cell opener may alternatively be a mixture of the aforementioned components such as the reaction of isocyanates and polyols with water. Hereinafter, a method and apparatus for producing a material incorporating such a reagent will be described.

5 shows an apparatus 300 for forming a composite material using a cell opener comprising a mixture of isocyanates and polyols. Hopper 110 receives and secures isocyanate 112. Isocyanate 112 may be, but is not limited to, aliphatic, cyclic saturated, prepolymers, diphenylmethane-4,4'-diisocyanate (MPI) and toluene diisocyanate (TDI), mixtures of these materials, and the like. Aliphatic isocyanates are preferred because they are less susceptible to discoloration. Hopper 114 receives and secures polyol 116. The polyol 116 may be, but is not limited to, polyether, polyester, mixtures thereof, and the like. The adhesion of the film formed therefrom is adjustable by adjusting the monool, diol or triol component of the polyol 116. Catalyst 118 may also be added to the hopper 114, which may be tin, tin stannous octarate, Dabco 33LV (available from Air Products Co., Wayne, Pennsylvania). , One of the NIAX family materials (available from Union Carbide, New York, NY), and mixtures thereof. The hopper 114 includes, but is not limited to, brighteners, crosslinkers (including but not limited to diethanolamine, triethanolamine, glycerin, etc.), ultraviolet light sensitizers, opacifiers, mixtures thereof, and the like. One or more additives 120 may be optionally added. Water 122 is also added. The material in the hoppers 110 and 114 flows through the conduits 124 and 126 and the valves 128 and 130, respectively, into the mixing head 132 (eg, impingement mixing head). Mixing head 132 feeds the mixture into foam 140 containing microcells (not shown) and into the pore forming wire 142 (infinite loops and moving onto two rollers 144 and 146). The mixed product is dispensed into a die head dispenser 134 that is extruded. Isocyanate 112 reacts with polyol 116 and water 122 to form polyurethane / polyurea; The byproduct of this reaction is carbon dioxide gas, which is produced in the foam to form a cellular structure.

Foam 140 is hot air cured (if necessary) by hot air source 150, which is a forced air dryer, microwave, infrared heat, convection, oven, other heat source, UV light or known to those skilled in the art. Other curing processes. This cured foam 140 is now a film 140. The niprolls 152 A and B, 154 A and B and 156 A and B combine to stretch the film 140 to minimize necking while maintaining film width. The niprole can be adjusted at different speeds to control the stretching properties. It will be appreciated that fewer or more pairs of niprols can be used to impart the desired stretching properties while minimizing necking.

Feed roll 160 supplies the non-extending facing 162 as described above, and feed roll 164 supplies the second non-extending facing 166. As the facings 162 and 166 are released, the sprayers 168 and 170 spray the adhesive 171 onto each facing to facilitate lamination to the film 140. Any commonly used adhesive can be used. An example of an adhesive is Findley 2525A, available from AtoFindley, Inc., Wowawatosa, Wisconsin, which is a urethane type adhesive. The film 140 is then sandwiched between the facings 162 and 166 and three layers are passed through one or more sets of niprols 172A and B (two or more sets of niprols may be used) to pass the laminated material 180. Form, and it is relaxed and wound or moved onto take-up roll 182 for post-formation processing or processing. It will be appreciated that one facing layer may be laminated to a film or multiple facing and film layers may be laminated together to form a thicker material.

In general, the present invention provides a composition comprising (a) providing an elastomeric material; (b) providing a cell opener; (c) mixing the polymeric material and the cell opener to form a mixture; And (d) extruding the mixture into a sheet through an extrusion die such that a thermode is formed at least partially in the sheet from decomposition of the cell opener to a gas, forming a cell during film lamination and elastomering. There is also provided a method of controlling the pore size distribution in a material.

The composite materials of the present invention can be used as ingredients in personal care products such as, but not limited to, diapers, training pants, absorbent underwear, adult incontinence products, feminine hygiene products, and similar performance products. The material may also be used in composites as stretchable top sheets (eg diapers, feminine hygiene products, etc.) for use in the management of viscous fluids, wherein the bilayer composite consists of a top film layer and a bottom layer, the top layer of which Thus consisting of at least 10% of the perforated elastic thermoplastic material. As the stretchable top sheet material or migration delay material, the area containing the cells may range from about 10% to about 50% of the total material. The thermode diameter may range from about 400 microns to about 3000 microns. The materials of the present invention can be used in fabrics, fibers or ribbon materials with laminated spunbond layers to produce headbands, waistbands, automotive knit fabrics, carpet backings, and the like. The perforated film layer itself can be used as an elastic foam in diaper waistbands or other compressible structures.

The materials of the present invention can be used as or in the outer cover or side panels of diapers, training pants and baby protective swim underwear. The material contains a specific luster that is reminiscent of the high quality elastic materials used in the field of adult swimwear. The high recoverability imparted to the elastic material helps to prevent urine or urine from leaking from such products into the surrounding pool environment. The material may also provide the appearance and feel of the actual swimsuit over a material that resembles a colored brief or diaper to look aesthetically beautiful.

Alternatively, the stretchable cellular material or composite of the present invention can be used as a topsheet material in personal care products to achieve improved fit and body fit to allow a direct path to fluid flow. In addition, the thermode can be tailored to change the shape and / or size of the thermode upon interaction with compressive or tensile forces such as imposed by the legs and body during normal wear. This change in size may facilitate the absorption or intake of mens liquids of varying elasticity and viscosity and reduce the chance of fluid rewet. For example, it is well known that large or hot pores not only increase the intake rate but also allow the passage of highly elastic or highly viscous components. However, large thermodes also allow reloading of low elastic fluids. Thus, the cellular elastic film can allow the inhalation of a range of mens fluids in both forms and reduce reloading. Alternatively, the cellular material of the present invention in film or fiber form can be used as a single material for use as spunbond facing in diapers and other personal care products to enhance both breathability and consistency.

Cellular materials and composites thereof of the present invention can be used in the field of health care and wound care, where properties such as stretch and breathability are important in wound covering, but allow interaction and exchange with air and the environment. These cellular materials and their composites are also valuable in apparel and apparel, where comfort, breathability and fit are all important. Specific features of the cellular material may be specified based on the end use field.

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

[Test process]

Air permeability

This test is used to determine the air-flow rate through known dry sample areas. The larger the resulting value, the more open the material, thus allowing more air to pass through it. The flow of air through the test specimen is measured by various orifices. The air permeability of the test specimen is measured from the decrease in pressure through this orifice and is digitally displayed in the selected unit of measure for direct reading. The air permeability tester used was the trade name Textest FX 3300, available from Schmid Corporation, Spartanburg, South Carolina. The test was performed in a standard laboratory atmosphere of 23 ± 1 ° C. (73.4 ± 1.8 ° F.) and 50% ± 2% relative humidity. The test specimens were used as such or cut to a size such that the specimens could extend beyond the clamping area.

Tension set

In this intermittent stress-extension experiment, the sample was repeated by stretching to a predetermined length, relaxing and then stretching back to the next greater length. The residual strain is then measured at a given time after the stress is removed. The set of tensions is a measure of the irreversibility of deformation.

Water Vapor Transport Rate (WVTR) -Celgard® Test

This test is used to determine the steady state vapor transfer rate ("WVTR") through various materials, including nonwovens, porous films, solid film materials, and the like. The material to be measured is sealed on top of one cup of water and placed in a temperature-controlled environment. The evaporation of water in the cup creates a vapor pressure inside the cup that is relatively higher than the vapor pressure of the environment outside the cup. This difference in vapor pressure causes steam inside the cup to flow through the test material out of the cup. The speed of this flow depends on the permeability of the test material sealed on top of the cup. The difference in cup weight at start and end is used to determine the rate of water vapor delivery. WVTR for the sample material was calculated according to the following method. Circular samples with a diameter of 3 inches (7.62 cm) were cut from each test material and control (2500 pieces of Celgard, purchased from Hoescht Celanese Corporation, Somerville, NJ). Celgard 2500 film is a porous polypropylene film. The test dish was a # 60-1 Vapormeter pan distributed by the Swing-Albert Instrument Company, Philadelphia, Pennsylvania. 100 ml of water were poured into each steaming pan and individual samples of test and control materials were placed over the open top of each pan. Tighten the screw-on flange to form a seal along the edge of the pan and expose the relevant test or control material to the surrounding atmosphere over a 6.5 cm diameter circle and have an exposure area of about 33.17 cm ² . The loaded steamometer cup was weighed and the weight recorded as the "total" weight. For example, a fan may be forced, such as a Blue M Power-O-Matic 60 oven, distributed by Blue M Electric Company of Blue Island, Illinois. Placed in an air oven. After 24 hours the pan was removed and reweighed (“after” weight).

The standardized WVTR for the tested sample was calculated as follows. Calculate the weight loss for each cup. The sample base velocity is calculated as follows.

Weight Loss Specimen Cup (g) x 7571 ÷ Test Time = Sample Base Rate (g / m ² / day).

Sample WVTR was calculated as follows.

(Sample Base Speed) x (5000 ÷ Average CellGuard® Base Speed)

= WVTR (standardized).

Rate of vapor transfer through nonwoven and plastic films using guard film and vapor pressure sensor-INDA Standard Test Method No. IST-70.4-99

At higher water vapor delivery rates, test procedures standardized by the Association of the Nonwoven Fabrics Industry (INDA), IST-70.4-99 (known to those skilled in the art) (incorporated herein by reference) further increase the delivery rate. It can be measured accurately. The INDA procedure provides a method of measuring the WVTR, which is the permeability of the film to water vapor, and the water vapor transmission coefficient for homogeneous materials.

INDA test methods are well known and will not be detailed herein. However, the test process is summarized as follows. The drying chamber is separated from the wet chamber where the temperature and humidity are known by the permanent guard film and the blocking material to be tested. The purpose of the guard film is to statically cool the air in the air gap while defining a constant air gap and characterizing the air gap. The drying chamber, guard film and wet chamber constitute the diffusion cell, in which the test film is sealed. The sample holder is known as Permatran-W model 100K manufactured by Mocon / Modern Controls, Inc., Minneapolis, Minnesota. The first test was made with the WVTR of the air gap between the guard film and the evaporator assembly to ensure 100% relative humidity. Water vapor diffuses through the air gap and guard film and then mixes with a dry gas stream proportional to the water vapor concentration. Send electrical signals to a computer for processing. The computer calculates the delivery rate of the air gap and the guard film and stores the value for further use.

The transfer rate of the guard film and the air gap is stored in the computer as CalC. The barrier is then sealed in the test cell. Again, water vapor diffuses through the air gap into the guard film and the test barrier and then mixes with the dry gas stream passing through the test barrier. Again, the mixture is conveyed to a vapor sensor. The computer then calculates the delivery rate of the combination of air gap, guard film and test film. This information is then used to calculate the rate of water transfer through the material tested according to the following equation.

TR ^-1 _{test barrier} = TR ^-1 _{test barrier, guard film, air gap} -TR ^-1 _{guard film, air gap}

Calculation:

WVTR: The calculation of WVTR uses the following equation.

WVTR = Fρ _sat (T) RH / Ap _sat (T) (1-RH)

In the formula,

F = flow (cc / min),

ρ _sat (T) = density of water in saturated air at temperature T,

RH = relative humidity at a specific location in the cell,

A = cross-sectional area of the cell, and

p _sat (T) = saturated vapor pressure of water vapor at temperature T.

Permeability: Use the following relationship to calculate the permeability (if necessary) of the sample:

Metric Perms = (WVTR) / P _w = g / m ² / day / mmHg

In the formula,

WVTR = sample vapor transfer rate, g / m ² days, and

P _w = water vapor partial pressure gradient across the test specimen, mmHg.

The water vapor permeability coefficient (if necessary) is calculated using the following relationship.

Permeability = Metric Pump x t

In the formula,

t = average thickness of the sample, cm. It should be noted that the permeability calculations are only meaningful if the material is determined to be homogeneous.

Stress-height

Stress-tension aspects of these polymers were obtained at both room temperature and body temperature using an Instron 1200 or Syntech 1 / S testing frame. A dog sample of about 30 mils thick and 0.5 inch (1.27 cm) in center bone width was clamped with a grip-to-grip distance of 2 inches (5.08 cm). Pulled in a cross-head configuration of 2 inches / minute (5.08 cm / minute). The sample failed to take at room temperature. In measurement at body temperature, the sample did not fail due to the height limitation of the surrounding chamber. Stress data were obtained by normalizing the load to the cross-sectional area. Elongation was calculated from knowledge of the length change and the original length of the sample. Modulus, a measure of the stiffness of the sample, was calculated from stress and elongation by applying the rubber elasticity theory as known to those skilled in the art.

The invention is illustrated in the drawings, in which like reference numerals designate the same or similar parts throughout the figures.

1 is a cross-sectional view of a portion of an elastomeric film laminated to a facing according to the present invention, showing various types of cells and thermodes that may be formed.

2 is a schematic diagram of a method of forming a composite material containing one facing and one elastomeric film layer.

3 is a schematic diagram of a method of forming a composite material containing two facings and one elastomeric film layer.

4 is a schematic view of a method of forming a composite elastic material containing one or more anisotropic elastic fibrous webs and one or more gatherable layers connected at spaced locations.

5 is a schematic diagram of a method of forming a composite elastomeric material using the reaction of a mixture of isocyanates and polyols with water as a cell opener.

Common film punching process using cell opener

Cellular film samples of the trademarked Kraton polymer (or other material) with or without additives comprising a cell opener, have a compression ratio of 5: 1 and a length: diameter (“L / D”) of 32: 1. Prepared on a Haake Rheocord 9000, 3/4 "screw extruder. The tip of the screw was fitted to the mixing components to produce a homogeneous mix. The screw had three heating zones: feed zone (50% of screw length), compression zone (30% of screw length), and metering zone (20% of screw length) The film die was also heated 0.5% of cell opener cellogen (Celogen) In a typical run comprising Creton polymer containing AZN 130, the feed zone temperature was set at 200 ° C., the compression zone was set at 210 ° C., the metering zone was set at 260 ° C. and the die temperature was 230 ° C. The microcellular film was 20 to 30 rpm. Extruded at a back pressure of 1900-2000 psi.These conditions may vary depending on the polymer used Other conditions may also be selected depending on the degree of opening and cell size requirements For example, increasing the speed of take-up rolls This reduces the thickness of the film and increases the average pore diameter Generally, pelletized polymers are blended with cell openers and other additives (if any) in dry or slurry form and introduced into the hopper of the extruder, with screw zones and dies The cast film with the desired properties was obtained by adjusting the temperature and RPM of the extruded film exiting the extruder die onto a cold roll and finally through a wind-up roll, adjusting the speed of this roll to the desired opening. A film with a closed cell, cell size and thickness was obtained.

The film material may then be laminated to one or more layers using conventional lamination techniques known to those skilled in the art.

Example 1

1671 g Kraton® 6912, SEPSEP Tetrablock Kraton® Copolymer                 

8.35 g (0.5%) Celogen® AZN 130

The extruder temperature was set as follows.

Setting temperature (℃) 200 210 260 230 Actual temperature (℃) 209 197 232 250

Extruder pressure was 1900-2000 psi. Screw speed was set to 20 rpm.

Example 2

390 g of Creighton (Kraton-registered trademark) 6588

Example 3

94% Estane® thermoplastic polyurethane 58245 (polyurethane from B.F.Goodrich)

5% EVA

1% Cellogen (registered trademark)

Example 4

99.5% Estane® 58245

0.5% Cellogen (registered trademark)

Example 5

100% Estane® 58245

Example number Sample description Air permeability 38 cm ² head cfm WVTR g / m ^2/24 sigan Break Elongation Load (Machine Direction) Gram Elongation at Break (Machine Direction)% One Kraton® 6712 + 0.5% Cellogen (Celogen®) 27 2361 519 607 2 Kraton (registered trademark) 6588 (control) no data 34 564 663 3 Estane® 58245 + 1% Celogen® + 5% EVA 14 2506 1985 308 4 Estane® 58245 + 0.5% Celogen® One 1175 5000 579 5 Celogen (registered trademark) 58245 (control) One 1117 5001 392

Example number Tensile% set at 25% elongation (machine direction) Tensile Set at 50% Elongation (Machine Direction) Tensile% set at 100% elongation (machine direction) Tensile Set at 200% Elongation (Machine Direction) Tensile set at 300% elongation (machine direction) One 2 4 7 11 16 2 no data no data no data no data no data 3 2 4 7 7 6 4 2 5 11 8 6

Tables 1 and 2 show the average test results of several samples of a given composition and process. In general, the test results indicate that the produced elastomeric film material maintains predictable air permeability, water / moisture barrier (WVTR), break elongation load and break elongation values compared to control samples. For example, WVTR was increased by adding Celogen compared to the control sample (Example 2) in Example 1.

Example 6-Film Lamination

Sample Description: SEBS saturated Kraton G polymer

0.15% Cellogen AZ130 Cell Opener

0.4 osy spunbond facings were used on both sides of the film.

The thickness of the film was 1-4 mm.

The extruder temperature was set to

Temperature (℃) 121 215.6 221.1

The die temperature was 210 ° C.

Sample number Test INDA IST 70.4-99 (g / m ^2/24 hours) Average 1300

Example 7-Lamination

Sample Description: SEBS Saturated Creighton G Polymer

0.06% Cellogen AZ130 Cell Opener

0.4 osy spunbond facings were used on both sides of the film.

The film was stretched to 3.6x and the thickness was 1-4 mm.

The extruder temperature was set as follows.

Temperature (℃) 121 215.6 221.1

Die temperature was 218.3 ° C.

Mean INDA IST 70.4-99 test was 133 g / m ^2/24 hours.

Example 8

Sample Description: SEBS Saturated Creighton G Polymer

0.06% Cellogen AZ130 Cell Opener

0.4 osy spunbond facings were used on both sides of the film.

The film was stretched to 3.8x and the thickness was 1-4 mm.

The extruder temperature was set as follows.

Temperature (℃) 121 215.6 221.1

Die temperature was 218.3 ° C. The take up rate was higher than in Example 7.

Mean INDA IST 70.4-99 test was 139 g / m ^2/24 hours.

As can be seen in the examples, WVTR breathability increased with increasing concentration of cellogen.

The present invention provides materials that maintain the predictable mechanical properties of previously known polymers with a decrease in density and an increase in WVTR. Olefin elastomers are generally inherently breathable to any appreciable degree. Polar elastomers have some degree of breathability. The present invention has shown that the addition of cell openers increases the breathability of elastomers. Thus, these examples show that elastomeric film materials can be grown commercially and are preferred over conventional perforated film materials such as polyolefins and also have the elastic advantages described above.

Although only a few exemplary embodiments of the invention have been described in detail above, those skilled in the art will readily appreciate that various modifications may be made among the exemplary embodiments without substantially departing from the novel teachings and advantages of the invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the following claims. It should further be understood that any patent, application or document cited herein is also incorporated by reference in its entirety.

Claims (59)

delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete A breathable cellular elastomeric filament material having a cell formed therein by a cell opener, not having a polystyrene homopolymer, at least a portion of the cell being closed, breathable, and having an elongation at break of 300 to 600 percent. The filament material of claim 33, wherein the filament material is of general formula ABA 'or AB, wherein A and A' are each thermoplastic polymer endblocks containing a styrene moiety, and B is elastic such as a conjugated diene or a lower alkene elastomer. Or a rubber copolymer midblock) and a breathable cellular elastomeric filament material comprising a material selected from the group consisting of ABAB tetrablock copolymers. 34. The breathable cellular elastomeric filament material of claim 33, further comprising at least one layer of extensible material laminated to the filament material to form a composite material, wherein the breathable cellular elastomeric filament material is formed by a cell opener and has at least one thermode defined therein. . 36. The breathable cellular elastomeric filament material of claim 35, wherein the cell opener is a material capable of forming an opening in the filament material. 36. The gas open according to claim 33 or 35, wherein the cell opener is azodicarbonamide, water, low boiling point solvent, fluorocarbon, mixture of isocyanate and polyol, mixture of isocyanate and polyol and gas liberated by reaction of water, or A breathable cellular elastomeric filament material that is a mixture thereof. 36. The breathable cellular elastomeric filament material of claim 35, wherein the cell is open, partially open, or closed to the surface of the filament material. 36. The method of claim 35, wherein the air-permeable cellular elastomer filament material and the composite material has an average water vapor transmission rate of from 300 to 20,000 g / m ^2/24 hours. The method of claim 35, wherein said composite material having a 300 to 20,000 g / m average water vapor transmission rate of ^2/24 hours as measured by INDA (Association of the Nonwoven Fabrics Industry) test procedure IST-70.4-99 ventilation Cellular elastomer filament material. 34. The method of claim 33, wherein the material has a cell formed therein by a cell opener, at least one of the cells is closed, the closed cell containing a solid, liquid or gas capable of releasing over time Breathable cellular elastomer filament material. 34. The breathable cellular of claim 33 wherein the material is a filament material having a cell formed therein by a cell opener, wherein the filament material is at least partially air permeable, capable of permeating water vapor therethrough, and extensible. Elastomeric filament material. 42. The breathable cellular elastomeric filament material of claim 41, wherein the solid, liquid, or gas is released in response to an external stimulus. 44. The breathable cellular elastomeric filament material of claim 43, wherein the external stimulus is increased temperature from a user. 44. The breathable cellular elastomer filament material of claim 43, wherein said solid, liquid, or gas is active. 44. The breathable cellular elastomeric filament material of claim 43, wherein said solid, liquid, or gas is capable of inhibiting yeast filament formation. 34. The breathable cellular elastomeric filament material of claim 33, further comprising at least one layer of extensible material laminated to the elastomeric material, wherein the elastomeric material is formed by a cell opener and has at least one thermode defined therein. . 36. The breathable elastomeric filament material of claim 35, wherein said filament material is formed by extrusion. 34. The method of claim 33, further comprising at least one layer comprising an extensible material laminated to the elastomer to form a laminate, wherein the elastic filament material has a thermode formed therein by a cell opener, wherein the laminate is A breathable cellular elastomeric filament material formed from personal care products. The method of claim 49, wherein the laminate is INDA (Association of the Nonwoven Fabrics Industry) the air-permeable cell having a 300 to 20,000 g / m average water vapor transmission rate of ^2/24 hours when measured by the test procedure IST-70.4-99 Elastomeric filament materials. 50. The breathable cellular elastomeric filament material of claim 49, wherein said laminate is a bandage, wound dressing, diaper, incontinence garment, panty shield or lining, sweating shield, surgical gown, or industrial workwear. Having a cell formed therein by the cell opener, which is at least partially air permeable, through which water vapor can permeate, is extensible, a) providing a spunbond material layer; b) does not have a polystyrene homopolymer, A thermode formed therein by mixing a polymer material and a cell opener to form a thermode therein, and extruding the mixture through a die, where the thermode includes the cell, at least a portion of the cell being closed Providing an elastic film layer having a; c) stretching the film of step b); And d) laminating the stretched film of step b) and the spunbond It is incorporated into the laminated material produced by a method comprising a, A breathable cellular elastomeric material that is breathable, has an elongation at break of 300 to 600 percent, and is retractable at least 75% of the elongation. Has a cell formed therein by the cell opener, does not have a polystyrene homopolymer, is at least partially air permeable and can permeate water vapor therethrough, a) providing an isocyanate material; b) providing a polyol material; c) providing a catalytic material; d) providing an effective amount of water; e) mixing the polyol material, catalyst material and water to form a mixture; f) mixing the mixture of step e) with said isocyanate material to form a second mixture; g) dispensing said second mixture on a surface through a die head to form a cellular foam, at least a portion of said foam having a closed cell; h) stretching the foam of step g); And i) stacking said stretched foam of step h) on at least one layer of non-extensible material to form a breathable elastic material It is incorporated into the laminated material produced by a method comprising a, A breathable cellular elastomeric material that is breathable, has an elongation at break of 300 to 600 percent, and is retractable at least 75% of the elongation. 54. The breathable cellular elastomeric material according to claim 53, wherein said method further comprises curing said foam. 54. The breathable cellular elastomeric material of claim 53, wherein the method further comprises adjusting polyol functionality to control the desired level of adhesion. Having a cell formed therein by the cell opener, which is at least partially air permeable, through which water vapor can permeate, is extensible, a) providing an elastomeric material having no polystyrene homopolymer; b) providing a cell opener material capable of releasing gas; c) mixing the polymeric material and the cell opener material to form a mixture; And d) extruding the mixture through an extrusion die such that the cell opener material produces gas such that at least part of the thermode is formed in the extruded material (at least a portion of the thermode is a closed cell) Having a thermode formed therein by a method comprising a Breathable Cellular Elastomer Filament Material. a) a layer of elastomeric filament material that does not have a polystyrene homopolymer and has a cell formed therein by a cell opener, at least a portion of the cell is closed, breathable, and has an elongation at break of 300% to 600% ; And b) at least one layer of spunbond material laminated to said elastomeric filament material Laminated material comprising a. a) a layer of elastomeric filament material that does not have a polystyrene homopolymer and has a cell formed therein by a cell opener, at least a portion of the cell is closed, breathable, and has an elongation at break of 300% to 600% ; And b) at least one layer of spunbond material laminated to said elastomeric filament material Personal hygiene article comprising a. a) a layer of elastomeric filament material that does not have a polystyrene homopolymer and has a cell formed therein by a cell opener, at least a portion of the cell is closed, breathable, and has an elongation at break of 300% to 600% ; And b) at least one layer of spunbond material laminated to said elastomeric filament material Elastic topsheet for use in articles worn to manage the fluid comprising a.

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