DE3689058T2 - Non-woven elastic pleated. - Google Patents

Description

The present invention relates to a method of forming a nonwoven elastic composite fabric bonded to a nonwoven gathered fabric and to a method of forming a nonwoven gathered fabric which exhibits elastic properties when separated from the nonwoven elastic fabric after gathering has been effected by contracting the elastic fabric.

In the field of cloth manufacturing, there has been a desire to provide a cloth covering which is (1) fully elastic over its entire surface -- to provide a tight yet comfortable fit, (2) water repellent -- to retain liquid materials within the confines of the cloth, (3) breathable -- to permit vapor exchange through the cloth material, (4) soft -- for improved comfort, and (5) inexpensive to manufacture -- so that the cloth can be economically marketed to the consumer.

Unfortunately, the known nonwoven composite materials that have been marketed to date lack one or more of these features. Furthermore, these elastic nonwoven composite materials have not been manufactured using economical processes.

For example, U.S. Patent 2,957,512 to Wade discloses a process for making an elastic composite sheet material in which a crimped or ribbed, flexible sheet material is bonded to, for example, elastic meltblown material. At column 5, lines 39-48, it is stated that a fibrous web of elastomeric material can be stretched and bonded to the ribbed web at spaced apart points or areas, and the composite assumes the structure illustrated in Figure 7 after the fibrous elastomeric web is allowed to relax.

Yet another method of forming an elastic composite fabric is disclosed in U.S. Patent 3,316,136 to Pufahl. The preferred method of making this fabric involves Utilizing an adhesive which is first applied to an elastic substrate in a predetermined pattern and the elastic substrate is subsequently stretched to an elongated state. While the elastic substrate is in the stretched, elongated state, an overlying fabric is brought into contact therewith and held in a pressure bond with the elastic substrate for a period of time sufficient to ensure adhesion of the two layers. After the applied adhesive dries, the tension on the elastic substrate is released causing the overlying fabric to gather in the areas designated by the adhesive.

U.S. Patent 3,485 to Evans discloses in Example 56 the manufacture of an elongatable nonwoven structure having a multi-step pattern structure having unidirectional elasticity from an initial sheet material. The structure is composed of two webs of polyester staple fibers having a web of spandex yarn therebetween. The webs are joined together by the use of hydraulic water jets which entangle the fibers of one web with the fibers of an adjacent web. During the entangling step, the spandex yarn is stretched 200%.

U.S. Patent 3,673,026 to Braun discloses a method of making a laminated fabric and particularly discloses a method of making a nonwoven, laminated fabric with controlled rise. In this method, separate webs of nonwoven material, e.g., crimped fabric or synthetic fleece, are elastically stretched to different lengths and laminated by bonding them together while in their different stretched states. The bonded webs are then relaxed so as to produce different degrees of shrinkage in each web with resultant separation of the webs into unbonded regions and controlled rise in the laminate. The differential stretching is stated to include the state where only one web actually tissue is stretched and the other tissue is held tension-free or almost tension-free.

U.S. Patent 3,687,797 to Wideman discloses a method for manufacturing a resilient cellulosic cushioning product obtained by laminating a cellulosic cushioning backing fabric to a pre-stretched polyurethane foam fabric. The method involves applying adhesive in a desired pattern to one of the fabrics, and then laminating the cushioning fabric to the pre-stretched polyurethane foam fabric. During lamination of the cushioning fabric to the polyurethane foam fabric, the foam fabric is held in a stretched state. After lamination of both fabrics, the tension on the pre-stretched polyurethane foam fabric is released to cause shrinkage of the foam fabric. The adhesive holds the cushioning product and the foam together, while allowing expansion in the areas between the adhesive areas. After the shrinkage can be further relaxed by moistening, the stresses still remain in the product.

U.S. Patent 3,842,832 to Wideman is directed to a disposable product such as a bandage and to a method of making the product. The product is made by passing a lengthwise oriented nonwoven material over a roller to thereby apply an adhesive to a surface of the nonwoven material. At the same time, a polyurethane fabric is heated and stretched lengthwise and adhered to the nonwoven material. Thereafter, a second nonwoven material is adhered to the other side of the polyurethane fabric to form a laminate consisting of a stretched polyurethane inner core and outer layers of unstretched nonwoven fabric which are adhered to the core by the adhesive. Next, the laminate is passed through a moistening device which results in a loosening of the bond between the outer layers of nonwoven fabric and the adhesive bonding the outer layers to the core layer of stretched polyurethane. This allows the stretched polyurethane layer to substantially to return to their original length, causing the outer non-woven layers to become deformed or curled, forming wrinkles.

U.S. Patent 4,104,170 to Nedza discloses a liquid filter with an improved stretched polypropylene element. Manufacture of the polypropylene element is accomplished by forming a spunbonded backing from a continuous polypropylene fiber that adheres to itself when laid down in a random pattern. Thereafter, a top layer of short polypropylene fibers is applied to the backing, e.g., by melt blowing the top layer onto a stretched layer of the backing.

A method of making an elastic fabric structure including fibers of a synthetic, organic, relatively elastomeric polymer and fibers of a synthetic, organic, elongate but relatively inelastic polymer is disclosed in U.S. Patent 4,209,563 to Sisson. The method comprises the steps of feeding the relatively elastic fibers and elongate but relatively inelastic fibers to a well-distributed random array on a porous mold surface of an unbonded fabric having random fiber intersects. Thereafter, at least some of the fiber intersections are bonded to form a continuous, consolidated web of fabric which is stretched to elongate some of the fibers in at least one direction and then relaxed so that the contraction of the fabric by the relatively elastomeric fibers provides for the stitching and bundling of the stretchable, relatively inelastic fibers. The feeding of the fibers to the porous mold surface is positively controlled and this positive control is contrasted in column 7, lines 19-33 of the patent with the use of air currents to feed the fibers. It is also stated in column 9, lines 44 et seq. of the patent that embossed patterns or smooth, heated nip rolls can be used to bond the fibers to form the continuous web.

U.S. Patent 4,296,163 to Emi et al. discloses a fiber composite having a fused construction of (A) a film-like mesh structure consisting of fibers of a synthetic elastomeric polymer, the individual fibers of which are randomly interconnected in irregular relationship to form a number of meshes of different sizes and shapes, the mesh structure having a recovery ratio of at least 70% in two randomly selected directions perpendicular to each other in the plane of the mesh structure after 10% elongation, and (B) a nonwoven, woven or film-like fiber structure consisting of short or long fibers, the fiber structure having a recovery ratio of less than 50% in at least one randomly selected direction after 10% elongation. It is stated that the elastic composite is suitable for use as various clothing-based and industrial materials such as filter cloths, absorbents and thermal insulation materials. Methods of forming the composite are described in column 6, lines 64 ff. and these methods include spinning together, see column 9, lines 15-41.

U.S. Patent 4,323,534 to DesMarais includes an extrusion process for a thermoplastic resin composition for fabric fibers having exceptional strength and good elasticity. In column 8, under the subheading "Fiber Formation," the melt blowing of a blended resin comprising 79.13% KRATON® G-1652, 19.78% stearic acid, 0.9g% titanium dioxide, and 0.1% Irganox® 1010 antioxidant is disclosed. It is stated that individual fibers were extruded from the melt blowing die.

U.S. Patent 4,355,425 to Jones discloses a pantyhose with a built-in elastic system to minimize puckering and provide a comfortable, conforming fit, and a method of assembling the pantyhose. A material made from meltblown KRATON® rubber is stated to be well suited as a pantyhose fabric material. It is further stated that a method of making meltblown KRATON® fabrics is disclosed and is shown schematically in Figure 8 of the patent.

The process that KRATON® G-1652 appears to use is discussed beginning at column 4, line 67 of the patent.

U.S. Patent 4,379,192 to Wahlquist discusses a method of forming an impermeable absorbent barrier web embodying film and fiber webs where one or more melt blowing nozzles melt blow discontinuous small diameter fibers directly onto a pre-consolidated web of continuous fibers. Column 3, lines 35-40 of the patent states that by forming the microfiber web directly onto the pre-consolidated continuous fiber web, primary bonds are created between the microfibers and the continuous fibers which bond the microfiber web to the continuous fiber web.

U.S. Patent 4,426,420 to Likhyani discloses hydraulically entangled spunlace fabrics composed of at least two types of staple fibers and methods of making them which include heat treating elastomeric fibers which behave as ordinary staple fibers until they are heat treated to impart improved stretch and resilience properties to the fabric. The method includes the steps of drawing a possibly elastomeric fiber and allowing it to relax between the drawing and winding steps.

U.S. Patent 4,446,189 to Romanek discloses a nonwoven fabric laminate which includes at least one layer of nonwoven fabric attached by needle punching to an elastic layer such that the nonwoven fabric layer is permanently stretched when the elastic layer is stretched within its elastic limits. When the elastic layer is allowed to relax and return substantially to its pre-stretched state, the nonwoven fabric layer is stated to exhibit increased rise as a result of its simultaneous relaxation. It is also stated that the nonwoven fabric laminate can be used to form garments having increased freedom of movement.

The abstract of Japanese document number 47-43150 discloses a process for producing a non-woven fabric having high strength, the process being carried out by (a) uniaxially stretching a sheet or film made from a mixture of incompatible polymers, (b) laminating this sheet or film with a layer of foamed polymer, (c) stretching the laminate at right angles to the substrate orientation and then (d) stretching in the substrate orientation. Preferred polymers are stated to include polyamides, linear polyesters and polyolefins. Preferably, the top layer is a polypropylene foam.

A Shell Chemical Company brochure entitled "KRATON® Thermoplastic Rubber" discusses KRATON® thermoplastic materials in general. This brochure is coded "SC: 198-83 printed in U.S.A. 7/83 SM".

The object underlying the present invention is to provide a new method for producing a nonwoven elastic composite fabric bonded to a fibrous nonwoven gathered fabric and a new method for producing a gathered nonwoven fabric, the resulting materials being elastic and having excellent softness and breathability as well as excellent water repellency properties.

According to the present invention, this object is achieved by

(1) a method of producing a nonwoven elastic composite fabric comprising a nonwoven elastic fabric bonded to a fibrous nonwoven gathered fabric, which comprises the following step:

(a) providing a non-woven elastic fabric, characterized in that it further comprises the following steps:

(b) stretching the nonwoven elastic fabric from at least about 125% of the relaxed length of the nonwoven elastic fabric to about 700% of the relaxed length of the nonwoven elastic fabric;

(c) forming a fibrous nonwoven gatherable fabric directly on a surface of the stretched nonwoven elastic fabric and bonding the stretched fibrous nonwoven gatherable fabric to the stretched nonwoven elastic fabric to form a nonwoven elastic composite fabric; and

(d) relaxing the non-woven elastic composite fabric to gather the fibrous non-woven gatherable fabric, and

(2) a process for producing a gathered non-woven fabric having elastic properties, comprising the following step:

(a) Providing an expandable and contractible mold surface

characterized in that it further comprises the following stages:

(b) stretching the mold surface from at least about 125% to about 700% of its unstretched length;

(c) forming a fibrous nonwoven gatherable fabric directly on the stretched mold surface to releasably bond the fibrous nonwoven gatherable fabric to the stretched mold surface;

(d) gathering the forming surface to gather the fibrous, non-woven, gatherable fabric; and

(e) separating the gathered fibrous non-woven gatherable fabric from the gathered forming surface.

Preferred embodiments of the present invention are presented in the dependent claims.

DEFINITIONS

The terms "elastic" and "elastomeric" are used interchangeably herein and mean any material which, upon application of a prestressing force, is elongatable to an elongated, prestressed length of at least 125%, i.e., about one and one-quarter of its relaxed, non-prestressed length, and which, upon release of the stretching and elongating force, recovers at least about 40% of its elongation. A hypothetical example which would meet this definition of an elastomeric material would be a 2.54 cm (one (1) inch) sample of a material which can be elongated to at least 3.18 cm (1.25 inches) and which, after being elongated to 3.18 cm (1.25 inches) and relaxed, recovered a length of no more than 2.92 cm (1.15 inches). Many elastic materials can be stretched much more than 25% of their relaxed length and many of them recover substantially to their original relaxed length upon release of the stretching, elongating force and this last class of materials is generally preferred for the purposes of the present invention.

When used herein, the term "recover" refers to a contraction of a stretched material upon termination of a prestressing force, following stretching of the material by application of the prestressing force. For example, if a material having a relaxed, non-prestressed length of 2.54 cm (one (1) inch) were to be elongated by 50% by stretching to a length of 3.81 cm (one and one-half (1.5) inches), the material would have a stretched length that would be 150% of its relaxed length. If this exemplary stretched material were to contract to a length of 2.79 cm (one-tenth (1.1) inch) after releasing the prestressing and stretching force, that is, the material would have recovered 80% (1.02 cm (0.4 inches)) of its elongation.

When used herein, the terms "non-elastic" or "non-elastomeric" refer to and include any material not encompassed by the terms "elastic" or "elastomeric".

When used herein, the term "meltblown microfibers" refers to small diameter fibers having an average diameter of no greater than about 100 microns, preferably a diameter of about 0.5 microns to about 50 mm, more preferably an average diameter of about 4 microns to about 40 microns, and which have been prepared by extruding a molten thermoplastic material through a plurality of fine, usually circular, die capillaries as molten yarns or filaments into a high velocity gas (e.g., air) stream which stretches the filaments of molten thermoplastic material while reducing their diameter to the range specified above. Thereafter, the meltblown microfibers are entrained by the high velocity gas stream and deposited on a collecting surface to form a web of random meltblown microfibers. Such a process is disclosed, for example, in U.S. Patent 3,849,241 to Butin, and the disclosure of that patent is hereby incorporated by reference.

When used herein, the term "co-spun microfibers" refers to small diameter fibers having a diameter no greater than about 100 microns, preferably having a diameter of from about 10 microns to about 50 microns, more preferably having a diameter of from about 12 microns to about 30 microns, and which are made by extruding a molten thermoplastic material as filaments through a plurality of fine, usually circular, capillaries of a spinneret having a diameter of the extruded filaments which is then rapidly reduced, for example, by draw-out or other well-known co-spinning mechanisms.

The manufacture of spun-together nonwoven fabrics is illustrated in U.S. Patent 4,340,563 to Appel and the disclosure of that patent is hereby incorporated by reference.

When used herein, the term "nonwoven fabric" includes any web of material that has been formed without using a textile weaving process that creates a structure of individual fibers interwoven with one another in a specifiable, repeating manner. Specific examples of nonwoven fabrics include, without limitation, a meltblown nonwoven fabric, a spunbond nonwoven fabric, an apertured film, a microporous fabric, or a carded staple fiber fabric. These nonwoven fabrics have an average basis weight of no more than about 300 gsm. Preferably, the nonwoven fabrics have an average basis weight of from about 5 gsm to about 100 gsm. More preferably, the nonwoven fabrics have an average basis weight of from about 10 gsm to about 75 gsm.

When used herein, the term "consisting essentially of" does not exclude the presence of additional materials that do not appreciably affect the elastomeric properties and characteristics of a given composition. Exemplary materials of this type include pigments, antioxidants, stabilizers, surfactants, waxes, flow enhancers, swept solvents, particulate material, and materials added to increase the processability of the composition.

When used herein, the term "styrene moiety" means a monomeric unit represented by the formula:

is pictured.

Unless specifically stated and defined or otherwise limited, the terms "polymer" or "polymer resin" as used herein typically include, for example, homopolymers, copolymers such as, for example, block, graft, random and alternating copolymers and terpolymers, and blends and variations thereof. Unless specifically limited otherwise, the terms "polymer" or "polymer resin" are intended to encompass all possible geometric configurations of the material. These configurations include, for example, isotactic, syndiotactic and random symmetries.

An important feature of the process of the present invention is that the fibrous nonwoven gatherable fabric is formed directly on a surface of the nonwoven elastic fabric while the nonwoven elastic fabric is maintained in a stretched, non-biased and elongated state.

The nonwoven elastic fabric may be formed, for example, by a meltblowing process or any other process for forming a nonwoven elastic fabric. For example, the nonwoven elastic fabric may be a web of elastic foraminous film as opposed to a meltblown fibrous nonwoven elastic fabric. The formed nonwoven elastic fabric has a normal, relaxed, unstretched, non-prestressed length. Thereafter, the nonwoven elastic fabric is elongated by being stretched.

In a subsequent process step, the fibrous nonwoven gatherable web is formed directly on the surface of the nonwoven web, for example, by either a meltblowing or spinning process or any other process for forming a fibrous nonwoven gatherable web, while maintaining the nonwoven elastic web in its elongated, stretched and prestressed length.

Since the fibrous nonwoven gatherable fabric is formed directly on the surface of the nonwoven elastic fabric while the nonwoven elastic fabric is kept in its stretched pre-tensioned length, the nonwoven elastic fabric is elongated, stretched and pre-tensioned in this process step and the fibrous nonwoven gatherable fabric is in an unshirred but gatherable state.

In one embodiment of the present invention, the bonding of the fibrous nonwoven gatherable fabric to the nonwoven elastic fabric is accomplished by heat bonding to fuse the two fabrics together. The heat bonding may be performed within the temperature range of about 50°C below the melting temperature of at least one of the materials used to form at least one of the two fabrics to about the melting temperature of at least one of the materials used to form at least one of the two fabrics. At high throughput rates, the heat bonding may be performed above the melting temperature of one or more of the materials used to form the fabrics. The heat bonding may also be performed under suitable conventional conditions under pressure. If desired, conventional sonic bonding techniques may replace the heat bonding steps.

In another embodiment of the present invention, the bonding of the fibrous nonwoven gatherable fabric to the stretched nonwoven elastic fabric is achieved solely by interlocking the individual fibers of the fibrous nonwoven gatherable fabric with the nonwoven elastic fabric during formation of the fibrous gatherable fabric on the surface of the elastic fabric. If the nonwoven elastic fabric is a fibrous nonwoven elastic fabric formed, for example, by melt blowing, the interlocking of the individual fibers of the fibrous nonwoven gatherable fabric with the fibrous nonwoven elastic fabric is achieved by interlocking the individual fibers of the fibrous gatherable fabric with the individual fibers of the fibrous elastic fabric. If the nonwoven elastic fabric is a film with holes, the bonding of the fibrous nonwoven fabric to the film is achieved by hooking the individual fibers of the fibrous gatherable fabric within the holes of the film.

In yet another embodiment discussed below, the bonding of the two fabrics together is further accomplished by forming the non-woven elastic fabric from an adhesive elastic material.

In all embodiments of the present method, the bonding of the two webs together can be further enhanced by applying pressure to the two webs after the gatherable web has been formed on the surface of the elastic web. Also, in each embodiment, the bonding of the two webs can be further enhanced by applying an adhesive material to the upper surface of the nonwoven elastic web prior to forming the fibrous nonwoven gatherable web thereon.

After the bonding of the two fabrics together to form an elastic composite fabric has been completed, the pre-tensioning force is removed from the non-woven elastic composite fabric and the elastic composite fabric is allowed to relax to its normal, relaxed, non-pre-tensioned length. Since the fibrous non-woven gatherable fabric is bonded to the non-woven elastic fabric while the non-woven elastic fabric is stretched, relaxing the non-woven elastic composite fabric results in the gatherable fabric being carried along with the contracting non-woven elastic fabric and thus being gathered.

After gathering the fibrous non-woven gatherable fabric by reducing the pre-tensioning force on the non-woven elastic composite fabric, the non-woven elastic composite fabric can be rolled up into rolls for storage and shipping. The elastic composite fabric can then be used to form a wide range of products, such as a covering layer for a cloth.

Optionally, the gathered nonwoven fabric may be separated from the nonwoven elastic fabric after it has been gathered by the retracting forces of the nonwoven elastic fabric. In this embodiment, the gathered nonwoven fabric may be used alone or in conjunction with a variety of other fabrics or film materials to form numerous different products. Interestingly, the separated gathered nonwoven fabric retains a substantial degree of its gathered structure and also exhibits elastic properties. The gathered nonwoven fabric may be formed in a gatherable state directly on the surface of the elastic nonwoven fabric, as discussed above, with the elastic nonwoven fabric in a stretched state.

When formed on the surface of the nonwoven elastic fabric, the fibrous nonwoven gatherable fabric is detachably bonded to the nonwoven elastic fabric while the nonwoven elastic fabric is held in its stretched, extended, pre-tensioned length. This results in the formation of a nonwoven elastic composite fabric including the nonwoven elastic fabric and the fibrous nonwoven gatherable fabric, the fibrous nonwoven gatherable fabric being detachably bonded to the nonwoven elastic fabric. Since the fibrous nonwoven gatherable fabric is formed directly on the surface of the nonwoven elastic fabric while the nonwoven elastic fabric is kept in its stretched, elongated, prestressed length, the nonwoven elastic fabric is stretched, elongated and prestressed at this stage of the process and the fibrous nonwoven gatherable fabric is in an unshirred but gatherable state.

The separable connection of the fibrous nonwoven gatherable fabric to the stretched, extended nonwoven elastic fabric is achieved by interlocking the individual fibers of the fibrous nonwoven gatherable fabric with the nonwoven elastic fabric during the formation of the fibrous nonwoven gatherable fabric on the surface of the nonwoven elastic fabric. If the nonwoven elastic fabric is a fibrous nonwoven elastic fabric formed, for example, by melt blowing, the separable connection of the fibrous nonwoven gatherable fabric to the fibrous nonwoven elastic fabric is achieved by interlocking the individual fibers of the fibrous gatherable fabric with the individual fibers of the fibrous nonwoven elastic fabric. If the non-woven elastic fabric is a perforated film, the separable connection of the fibrous non-woven fabric to the non-woven elastic fabric is achieved by hooking the individual fibers of the fibrous gatherable fabric within the holes of the perforated film.

After the two fabrics are separably joined together to form the composite elastic fabric, the prestressing force is released from the composite elastic nonwoven fabric and the composite elastic fabric is allowed to contract to its normal contracted prestressed length, which is attributable to the contraction of the stretched nonwoven elastic fabric. Since the fibrous nonwoven gatherable fabric is separably joined to the nonwoven elastic fabric while the nonwoven elastic fabric is stretched and extended, the contraction of the nonwoven elastic fabric results in the gatherable fabric being carried along with the contracting nonwoven elastic fabric and thus being gathered on the surface of the composite elastic nonwoven fabric.

After gathering of the fibrous non-woven gatherable fabric has taken place by reducing the pre-tensioning force on the non-woven elastic composite fabric, the gathered fibrous nonwoven fabric is separated from the nonwoven elastic fabric and the gathered fabric can be rolled up for storage, for example. After separating the fibrous nonwoven gathered fabric from the nonwoven elastic fabric, the nonwoven elastic fabric can be reused as a molding surface.

After its separation from the nonwoven elastic fabric, the fibrous nonwoven gathered fabric retains a gathered configuration and upon application of a stretching and pre-tensioning force in the direction in which the fibrous nonwoven gatherable fabric was gathered, the gathered fabric stretches to the extent that the gathering allows. Importantly, after the stretching and pre-tensioning force is released, the stretched fibrous nonwoven gathered fabric essentially returns to the gathered configuration and length it had after its separation from the nonwoven elastic fabric. That is, the fibrous nonwoven gathered fabric exhibits elastic characteristics and properties. The fact that the gathered fabric retains a gathered configuration after being separated from the nonwoven elastic fabric is surprising. However, it is even more surprising that the separated fibrous nonwoven gathered fabric, after being stretched to an elongated length, exhibits elastic properties such as recovery to at least about 40% of its elongation. That is, the separated fibrous nonwoven fabric exhibits elastic or elastomeric properties as defined herein. In fact, the fibrous nonwoven gathered fabric has been found to exhibit these elastic properties even when the fibrous nonwoven gathered fabric was formed from a nonelastic material such as polypropylene.

Preferably, the fibrous nonwoven gatherable web includes at least one meltblown fibrous nonwoven web. Alternative processes which may be used in forming the fibrous nonwoven gatherable web include spinning or any other Methods for forming a fibrous nonwoven gatherable fabric. The gatherable fibrous nonwoven fabric may be formed entirely from a non-elastic material or from a blend of one or more non-elastic materials. However, the gathered fibrous nonwoven fabric may be formed from blends of one or more non-elastic materials with one or more elastic materials or from one or more elastic materials. Non-elastic materials for forming the fibrous nonwoven gatherable fabric include non-elastic polyester materials, non-elastic polyolefin materials, or blends of one or more non-elastic polyester materials with one or more non-elastic polyolefin materials. An exemplary non-elastic polyester material is polyethylene terephthalate. An exemplary non-elastic polyolefin is a non-elastic polypropylene which can be obtained under the trade designation PF 301.

Alternatively, the need for the elastic nonwoven fabric can be eliminated by directly forming the gathered nonwoven fabric in a gatherable state on a stretchable and contractable surface such as, for example, a stretchable and retractable mesh film as in the second method of the present invention.

In a particular embodiment of the process of the present invention, an adhesive fibrous nonwoven elastic web is formed, for example, by melt blowing microfibers of an adhesive elastic material such as, for example, an AB-A' block copolymer or blends of such ABA' block copolymers with poly(alpha-methylstyrene), wherein A and A' are each thermoplastic polystyrene or polystyrene homolog endblocks and B is an elastic polyisoprene midblock. In some embodiments, A may be the same thermoplastic polystyrene or polystyrene homolog endblock as A'. The adhesive fibrous nonwoven elastic web is then elongated by being rolled onto an elongated, stretched length, and a fibrous nonwoven gatherable fabric is formed, for example, by meltblowing or spinning the fibrous nonwoven gatherable fabric directly onto a surface of the adhesive fibrous nonwoven elastic fabric while the fibrous nonwoven elastic fabric is maintained at its stretched length. As a result of the fact that the fibrous nonwoven elastic fabric is adhesive, the fibrous nonwoven gatherable fabric is simultaneously formed on the surface of the adhesive fibrous nonwoven elastic fabric and bonded to the surface thereof. This embodiment results in the formation of a nonwoven elastic composite web having an unshirred fibrous gatherable web adhesively bonded to the adhesive fibrous nonwoven elastic web, the bonding of the two webs together being achieved by the adhesive bond which occurs on the surface of the fibrous nonwoven elastic web during formation of the fibrous nonwoven gatherable web. The adhesive bonding of the two webs together can be enhanced by applying pressure to the nonwoven elastic composite web by passing the nonwoven elastic composite web through the nip between rollers which may be unheated after the composite web has been formed but before allowing the fibrous adhesive nonwoven elastic web to recover. The adhesive bond can be further enhanced by applying an adhesive material to the surface of the adhesive fibrous nonwoven elastic material prior to formation of the gatherable web thereon.

The nonwoven elastic fabric is then allowed to relax to its normal, relaxed, non-prestressed length. Since the fibrous nonwoven gatherable fabric was bonded to the adhesive fibrous nonwoven elastic fabric while the adhesive fibrous nonwoven elastic fabric was in a stretched state, relaxing the composite nonwoven elastic fabric and hence the adhesive fibrous non-woven elastic fabric results in the gatherable fabric being carried along with the contracting fibrous non-woven elastic fabric and thus being gathered.

After gathering of the fibrous nonwoven gatherable fabric has occurred, the nonwoven elastic fabric can be rolled into rolls for storage and shipping. To avoid sticking of the exposed side of the adhesive fibrous nonwoven elastic fabric after rolling of the nonwoven elastic composite fabric, it is preferred that a second fibrous nonwoven elastic fabric be applied to the exposed surface of the fibrous nonwoven elastic fabric prior to the gathering step. Optionally, meat wrapping paper can be applied to the exposed adhesive surface of the adhesive fibrous nonwoven elastic fabric either prior to or after gathering of the gatherable fabric and later removed prior to use of the nonwoven elastic composite fabric.

Exemplary elastomeric materials for use in forming the fibrous nonwoven elastic web include polyester elastomeric materials, polyurethane elastomeric materials, and polyamide elastomeric materials. Other elastomeric materials for use in forming the fibrous nonwoven elastic web include (a) A-B-A' block copolymers, wherein A and A' are each a thermoplastic polymer endblock including a styrene moiety and wherein A may be the same thermoplastic polymer endblock as A', such as a poly(vinylarene), and wherein B is a polymer elastomer midblock such as a conjugated diene or a lower alkene, or (b) blends of one or more polyolefins or poly(alpha-methylstyrene) with AB-A' block copolymers, wherein A and A' are each a thermoplastic polymer endblock including a styrene moiety, wherein A may be the same thermoplastic polymer endblock as A', such as such as a poly(vinylarene) and wherein B is a polymer elastomer midblock such as a conjugated diene or a lower alkene. The A and A' end blocks can be selected from the group including polystyrene and polystyrene homologues, and the B midblock can be selected from the group including polyisoprene, polybutadiene, or poly(ethylene-butylene). When A and A' are selected from the group including polystyrene or polystyrene homologues, and B is poly(ethylene-butylene), materials that can be blended with these block copolymers are polymers including copolymers of ethylene, propylene, butene, other lower alkenes, or one or more of these materials. When A and A' are selected from the group including polystyrene or polystyrene homologues, and B is a polyisoprene midblock, poly(alpha-methylstyrene) is a material for blending with this type of block copolymer.

Preferably, the gatherable fabric includes at least one fibrous nonwoven fabric including non-elastic fibers that may be formed by meltblowing, co-spinning or any other process for forming a fibrous nonwoven gatherable fabric. Preferred materials for forming the gatherable fabric include polyester materials, polyolefin materials, or blends of one or more polyester materials with one or more polyolefin materials. An exemplary polyester material is polyethylene terephthalate. An exemplary polyolefin material is polypropylene.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic view illustrating a way of performing the method of one of the embodiments of the present invention.

Fig. 2 is a schematic view illustrating a way of performing the method of another embodiment of the present invention.

Fig. 3 is a schematic view showing a way of carrying out the method of an embodiment of the present Invention illustrates where the gathered fabric is separated from the elastic fabric.

Fig. 4 is a schematic view illustrating another way of performing the method of another embodiment of the present invention where the gathered fabric is separated from the elastic fabric.

Figure 5 is a top plan view of a non-biased and retracted, stretchable and retractable forming film which can be used as a forming film in the process illustrated in Figure 4.

Figure 6 is a top plan view of the stretchable and retractable forming film of Figure 5 in the pre-stressed, elongated configuration.

Fig. 7 is a schematic view of yet another way of performing the method of yet another embodiment of the present invention where the two gathered fabrics are separated from the elastic fabric.

Turning now to the figures, wherein like reference numerals indicate like structures, and particularly to Fig. 1, it can be seen that meltblown microfibers 10 formed by a conventional meltblowing nozzle 12 are collected on a porous collecting film 14 which moves over the rollers 18 and 20 as indicated by the arrows 16 in Fig. 1. The material used to form the meltblown microfibers 10 is an elastomeric material for reasons which will become apparent hereinafter. The porous collecting film 14 is driven by the rotating rollers 18 and 20 which in turn are driven by a conventional drive device (not shown). For the sake of clarity, a conventional vacuum chamber disposed between the rollers 18 and 20 and beneath the lower surface of the upper portion of the film 14 is also not shown. The vacuum chamber supports the retention of the microfibers 10 on the upper surface of the film 14. As the meltblown microfibers 10 are deposited on the moving collecting film 14, they become entangled and adhere to one another to form a continuous fibrous nonwoven elastic web 22. The entangled continuous nonwoven elastic web 22 is guided through the porous collecting film 14 to the nip or squeezing gap 24 between the rotating roller 20 and a rotating nip roller 26. The nip or squeezing gap 24 between the two rollers 20 and 26 is adjusted so that the rollers 20 and 26 tightly grip the fibrous nonwoven elastic web 22 without adversely affecting the web 22. The rotational speed of the rollers 20 and 26 is adjusted so that the peripheral surface speed of the rollers 20 and 26 is substantially the same as the speed of the moving porous capture film 14. If the meltblown microfibers 10, after being deposited on the surface of the porous film 14, are insufficiently cohesive to form a cohesive web 22 capable of performing the stretching and relaxing steps discussed below without being adversely affected (e.g., if the web separates after a stretching force is applied, it loses its integrity), the cohesion of the microfibers to one another can be improved, for example, by heat bonding the microfibers 10 to one another by maintaining the roller 26 at a suitable elevated temperature, which will vary depending on the degree of cohesion desired and the cohesive properties of the material used to form the microfibers 10. Typical heat bonding temperatures range from about 50°C below the melting temperature of at least one of the materials used to form the web 22 to about the melting temperature of at least one of the materials used to form the web 22. However, at high throughput rates, temperatures exceeding the melting temperature of the material may be used. After passing through the nip 24, the fibrous nonwoven elastic web 22 is forced by the action of the rollers 20 and 26 to a second nip or nip 28 which is located between a rotating roller 30 and a second rotating nip roller 32. is formed, conveyed and passed through. The rotation of the rollers 30 and 32 is adjusted so that the surface peripheral speed of the rollers 30 and 32 is greater than the surface peripheral speed of the rollers 20 and 26. The nip 28 between the two rollers 30 and 32 is adjusted so that the rollers 30 and 32 firmly grasp the fibrous nonwoven elastic fabric 22 without adversely affecting the fabric 22. As a result of the increase in the surface peripheral speed of the rollers 30 and 32 with respect to the surface peripheral speed of the rollers 20 and 26, a longitudinal or machine direction (MD) prestressing force is applied to the fibrous nonwoven elastic fabric 22 and the fabric 22 is stretched in the longitudinal or machine direction (MD) to an elongated, stretched, prestressed length. The degree of stretch of the fibrous nonwoven elastic fabric 22 occurring in the area 34 between the rollers 20 and 26 and the rollers 30 and 32 can be varied by, for example, varying the peripheral surface speed of the rollers 30 and 32 with respect to the peripheral surface speed of the rollers 20 and 26. For example, if the peripheral surface speed of the rollers 30 and 32 is twice that of the rollers 20 and 26, the fibrous nonwoven elastic fabric 22 will be stretched to a stretched length of substantially twice, i.e., about 200%, its original relaxed, unstretched, non-prestressed length. The fibrous nonwoven web 22 is stretched to a stretched length of at least 125% of its original relaxed, non-biased length, preferably from at least about 150% of the relaxed, non-biased length of the fibrous nonwoven web 22 to about 700% or more of the relaxed, non-biased length of the fibrous nonwoven web 22.

After the fibrous non-woven elastic web 22 has been stretched by the combined actions of the rollers 20 and 26 and 30 and 32, the web 22 is directed to a second porous collecting belt 36 which moves as indicated by the arrows 38 in Fig. 1. The second porous collecting belt 36 moves around the rotating roller 30 in conjunction with a rotating roller 40 and is driven thereby. The moving rollers 30 and 40 are in turn driven by a conventional drive device (not shown), which may be the same arrangement that drives the rotating rollers 18 and 20. For the sake of clarity, a conventional vacuum chamber disposed between the rollers 30 and 40 and beneath the lower surface of the upper portion of the belt 36 is also not shown. The vacuum chamber assists in retaining the web 22 on the upper surface of the belt 36. The stretched, fibrous, nonwoven, elastic web 22 is guided by the second porous collecting belt 36 to a nip or nip 42 formed between the rotating roller 40 and a third rotating nip roller 44. The rotation of the rotating roller 40 and the nip roller 44 is adjusted so that the surface peripheral speed of the two rollers 40 and 44 is substantially equal to the surface peripheral speed of the rollers 30 and 32. Since the surface peripheral speed of the rollers 40 and 44 is maintained at substantially the same surface peripheral speed as that of the rollers 30 and 32 and since the nip gap 42 is adjusted so that the rollers 40 and 44 firmly receive the fibrous nonwoven elastic fabric 22 without adversely affecting the fabric 22, the stretched state of the fibrous nonwoven elastic fabric 22 is maintained while the fibrous nonwoven elastic fabric 22 is entrained by the second porous collecting belt 36.

As the stretched fibrous nonwoven elastic web 22 is carried along by the second porous collecting belt 36, meltblown microfibers 46 formed by a conventional meltblowing nozzle 48 are meltblown directly onto the upper surface of the stretched nonwoven elastic web 22 to form a continuous fibrous nonwoven gatherable web 50 located on the upper surface of the stretched fibrous nonwoven elastic web 22. Care should be taken in adjusting the distance between the nozzle tip the meltblowing nozzle 48 and the elastic web 22 and the speed at which the elastic web 22 passes under the nozzle tip of the meltblowing nozzle 48, since it has been found that the hot air leaving the nozzle tip melts the elastic web 22 if these adjustments, which vary with the material or blend of materials from which the elastic web is formed, are not properly made. When the meltblown microfibers 46 are collected on the upper surface of the fibrous nonwoven elastic web 22, they entangle and adhere to one another to form the continuous fibrous nonwoven gatherable web 50. Depending on the distance between the nozzle tip of the meltblowing nozzle 48 and the top surface of the stretched fibrous nonwoven elastic web 22, the meltblown microfibers 46 may also mechanically entangle with the fibers of the elastic web 22. As the distance between the nozzle tip of the meltblowing nozzle 48 and the top surface of the stretched fibrous nonwoven elastic web 22 is increased, the mechanical entanglement of the fibers of the web 50 with the fibers of the web 22 generally decreases. To ensure the mechanical entanglement of the fibers of the web 50 with the fibers of the web 22, the distance between the nozzle tip of the meltblowing nozzle 48 and the top surface of the web 22 should be no greater than about 63.5 cm (25 inches). Preferably, the distance between the nozzle tip of the meltblowing nozzle 48 and the upper surface of the web 22 should range from about 15.24 cm (6 inches) to about 40.64 cm (16 inches). Depending on the materials used to form the webs 22 and 50 and the distance between the nozzle tip of the meltblowing nozzle 48 and the upper surface of the web 22, some adhesion of the fibers of the gatherable web 50 to the fibers of the elastic web 22 may also occur. The materials suitable for use in forming the fibrous nonwoven elastic web 22 are preferably selected after the selection of the material or materials used in forming the fibrous nonwoven gatherable web 50. In particular, the material used to form of the fibrous nonwoven gatherable fabric may be a material that forms a web 50 that is gatherable by the constrictive force of the fibrous nonwoven elastic web 22. Since the constrictive force of the web 22 varies with the material selected to form the web 22, the material selected to form the web 22 must be selected so that the constrictive force of the web 22 is capable of gathering the web 50. Exemplary materials for use in forming the webs 22 and 50 are disclosed below.

Depending on the characteristics desired in the final product, the materials used to form the fibers that make up the two webs 22 and 50, and the processing steps/conditions used, the two contiguous webs 22 and 50 can be joined together in a variety of ways. For example, if a relatively weak bond between the two webs 22 and 50 is desired, the two webs 22 and 50 can be joined together only by the entanglement of the individual meltblown fibers of the fibrous nonwoven gatherable web 50 with the individual meltblown fibers of the fibrous nonwoven elastic web 22, which occurs on the stretched surface of the web 22 during formation of the web 50. In this embodiment, the two webs 22 and 50 are separable from one another upon application of a relatively small force, such as a light pulling or rubbing force exerted by a person's fingers. In the event that a stronger bonding of the two contiguous fabrics 22 and 50 together is desired, the bonding of the fibrous nonwoven gatherable fabric 50 to the fibrous nonwoven elastic fabric 22 can be accomplished by heat bonding the two fabrics 22 and 50 together while still maintaining the fibrous nonwoven elastic fabric 22 at its stretched length. Heat bonding can be accomplished, for example, by passing the two fabrics 22 and 50 between rollers 40 and 44, with rollers 40 and 44 being configured to apply appropriate heat bonding temperatures and pressures to the two fabrics 22 and 50. For example, bonding the fibrous nonwoven gatherable web 50 to the fibrous nonwoven elastic web 22 may be accomplished by heat bonding the two webs 22 and 50 together using the rollers 40 and 44 within the temperature range of about 50°C below the melting point of at least one of the materials used to form the webs 22 and 50 to about the melting temperature of at least one of the materials used to form the webs 22 and 50. However, at high throughput rates, heat bonding may be accomplished above the melting temperature of one or more of the materials used to form the webs 22 and 50 because the webs 22 and 50 are exposed to the high temperatures for a short time. Heat bonding the two webs 22 and 50 together under pressure may be accomplished at conventional, suitable bonding pressures by adjusting the nip 42. Other conventional alternatives for heat bonding the two webs 22 and 50 together may replace the heat bonding steps. For example, a conventional sonic bonding assembly (not shown) may replace the hot bonding assembly 40 and 44. It should be noted that bonding of the two webs 22 and 50 together is usually only somewhat enhanced by passing the webs 22 and 50 through the nip 42, since each such pass results in the application of pressure to the two webs 22 and 50 and thus increased entanglement of the individual fibers of the two webs 22 and 50.

After the fibrous nonwoven elastic web 22 has been joined to the fibrous nonwoven gatherable web 50 to form a nonwoven elastic composite web 52 (separable or non-separable depending on the final product desired), the prestressing force on the fibrous nonwoven elastic web 22 is released, for example, by passing the nonwoven elastic composite web 52, which includes both the fibrous nonwoven elastic web 22 and the fibrous nonwoven gatherable web 50, through the nip or nip 54 formed by a pair of rotating nip rolls 56 and 58. The nip is adjusted so that the rollers 56 and 58 firmly grasp the composite fabric 52 without adversely affecting the composite fabric 52. The rotation of the nip roller pair 56 and 58 is adjusted so that the surface peripheral speed of the nip rollers 56 and 58 allows the nonwoven elastic composite fabric 52 to relax and contract to its relaxed, non-prestressed length as a result of its elastic properties. The relaxing and contracting of the nonwoven elastic composite fabric 52 to its relaxed, non-prestressed length results in the fibrous nonwoven gatherable fabric 50 joined to the fibrous nonwoven elastic fabric 22 being entrained along the upper surface of the gathering fibrous nonwoven elastic fabric 22, that is, being contracted and thus gathered thereon.

After relaxing and contracting the nonwoven, elastic composite fabric 52, the composite fabric 52 can be rolled up onto a supply roll for storage and shipping. The nonwoven, elastic composite fabric 52 can then be used in the manufacture of a wide variety of articles, such as, for example, a facestock material for a cloth or other garment.

If the gathered nonwoven fabric 50 is to be separated from the elastic nonwoven fabric 22, the separation of the two fabrics 22 and 50 from one another in this embodiment is optionally accomplished by passing the fibrous nonwoven gathered fabric 50 through the nip 62 between two rotating nip rolls 64 and 66 and passing the nonwoven elastic fabric 22 through the nip 68 between two rotating nip rolls 70 and 72. The nip rolls 62 and 68 are adjusted so that the rolls 64 and 66 encompass the fabric 50 without adversely affecting the fabric 50 and the rolls 70 and 72 encompass the fabric 22 without adversely affecting the fabric 22. After the two fabrics 22 and 50 have been separated, the two fabrics 22 and 50 are placed on the template roll 74 , respectively. In rolling up the fibrous nonwoven gathered web 50, care should be taken not to store the web 50 under high tension or to pre-tension it in an unshirred state, since if the web 50 is stored in a rolled, tensioned, unshirred state, it is likely that the web 50 will lose its ability to retain its gathers. The loss of gathers in the web 50 results in a loss of the elastic properties of the web 50. Accordingly, to maintain the gathered state of the web 50 while the web 50 is stored, the rotation of the feed roll 76 should be adjusted so that the peripheral surface speed of the roll 76 is generally equal to or only slightly greater than the peripheral surface speed of the rollers 64 and 66.

After being separated from the nonwoven elastic fabric 22, the gathered fibrous nonwoven fabric 50 exhibits a creped or gathered appearance. Accordingly, upon application of a stretching force in the machine direction (i.e., a direction substantially perpendicular to the gather lines), the fabric 50 is stretched to the length that allows gathering, i.e., until the fabric 50 assumes a generally planar configuration as opposed to a gathered configuration, and surprisingly, upon release of the stretching force on the gather, the gathered fabric 50 exhibits elastic properties as defined herein. The gathered fabric 50 exhibits elastic properties even when the fabric 50 is formed from a nonelastic material, such as polypropylene obtained from Himont Corporation under the trade designation PF 301.

The fibrous nonwoven elastic fabric portion 22 of the nonwoven elastic composite fabric 52 may be formed from any elastomeric material that can be formed into a fibrous nonwoven elastic fabric 22. Exemplary elastomeric materials for use in forming the fibrous nonwoven elastic fabric 22 include polyester elastomeric materials such as, for example, elastic polymer materials available under the trade name Hytrel® from EI DuPont DeNemours & Co., polyurethane elastomer materials such as polyurethane elastomer materials available under the trade name Estane® from BF Goodrich & Co., and polyamide elastomer materials such as polyamide elastomer materials available under the trade name Pebax® from Rilsan Company. Other elastomeric materials for use in forming the fibrous nonwoven elastic web 22 include (a) elastomeric AB-A' block copolymers, wherein A and A' are each a thermoplastic polymer endblock including a styrene portion, and wherein A is the same thermoplastic polymer endblock as A', for example a poly(vinylarene), and wherein B is an elastomeric polymer midblock such as a conjugated diene or a lower alkene, and (b) blends of one or more polyolefins or poly(alpha-methylstyrene) with elastomeric AB-A' block copolymer materials, wherein A and A' are each thermoplastic polymer endblocks including a styrene portion, and wherein A may be the same thermoplastic polymer endblock as A', such as a poly(vinylarene), and wherein B is an elastomeric polymer midblock such as a conjugated diene or a lower alkene. The A and A' materials can be selected from the group of materials including polystyrene or polystyrene homologues and the B materials can be selected from the group of materials including polyisoprene, polybutadiene and poly(ethylene-butylene). Materials of this general type are disclosed in U.S. Patents 4,323,534 to Des Marais and 4,355,425 to Jones and the aforementioned Shell brochure. Commercially available elastomeric AB-A' block copolymers having a saturated or substantially saturated poly(ethylene-butylene) center block "B" represented by the formula:

where x, y and n are positive integers, and polystyrene end blocks A and A', which are represented by the formula:

where n is a positive integer which may be the same or different for A and A' are sometimes referred to as S-EB-S block copolymers and are available from Shell Chemical Company under the trade designation KRATON® G, for example KRATON® G 1650, KRATON® G 1652 and KRATON® GX 1657. Other elastomeric resins which may be used are AB-A' block copolymers, where A and A' are polystyrene endblocks as defined above and "B" is a polybutadiene midblock represented by the following formula:

where n is a positive integer. This material is sometimes referred to as an SBS block copolymer and is available under the trade designation KRATON® D, for example KRATON® D 1101, KRATON® D 1102 and KRATON® D 1116 from Shell Chemical Company. Another SBS block copolymer material can be obtained under the trade designation Solprene 418 from Phillips Petroleum Company. Still other elastomeric resins which can be used as AB-A' block copolymers are where A and A' are polystyrene endblocks as defined above and B is a polyisoprene midblock wherein the midblock is represented by the formula:

where n is a positive integer. These block copolymers are sometimes referred to as S-I-S block copolymers and are available from Shell Chemical Company under the trade name KRATON® D, for example KRATON® D 1101, KRATON® D 1102 and KRATON® D 1116.

A summary of the typical properties of the above-identified KRATON® D and KRATON® G resins at 23ºC (740 Fahrenheit) is shown below in Tables I and II. TABLE I KRATON® D PROPERTY Tensile strength Modulus Elongation Elongation at break Hardness, Shore A Specific gravity Brookfield viscosity (toluene solution) Melt viscosity, melt index, condition G, g/10 min Processing oil content, wt.% Styrene/&sup6; Rubber Ratio Physical Form Porous Pellet TABLE II KRATON® G Tensile Strength Modulus Elongation Elongation at Break Hardness, Shore A Specific Gravity Brookfield Viscosity (Toluene Solution) Melt Viscosity, Melt Index, Condition G, g/10 min Plasticizer Oil Content, wt. % Styrene/6 Rubber Ratio Physical Form Friable Pellet ¹ ASTM Method D412 Tensile Test, Jaw Separation Speed 25.4 cm (10 in.)/min ² Typical Properties Determined on a Film Cast from a Toluene Solution ³ Neat Polymer Concentration, 25 wt. % ⊚ Neat Polymer Concentration, 20 wt. % ⊚ Property Determined by Extrapolating Results Measured on Oil-Extended Films Cast from a Toluene Solution to Zero Oil Content ⊚ Ratio of Sum of Molecular Weights of Endblocks (A + A') to Molecular Weight of B Midblock For example, with respect to KRATON® G-1650, the molecular weight of the endblocks (A + A') is 28% of the molecular weight of the ABA' block copolymer

Melt blowing of the S-EB-S KRATON® G block copolymer in neat, i.e. undiluted form has proven difficult except at elevated temperatures and low flow rates, such as from at least 287.8°C (550 degrees Fahrenheit) to about 329.4°C (625 degrees Fahrenheit) or more and less than at least about 0.14 g per die capillary per minute. To avoid these elevated temperature and low flow conditions, it has been found that blending certain materials with several of the different types of KRATON® G materials provides a satisfactorily melt blowable material. For example, blends of certain polyolefin materials with the S-EB-S block copolymer have resulted in a melt blowable material. Particularly when a polyolefin is to be blended with the KRATON® GS-EB-S block copolymers, the polyolefin is preferably a polymer, including copolymers, of ethylene, propylene, butene, other lower alkenes, or mixtures of one or more of these materials. A particularly preferred polyolefin for blending with the KRATON® GS-EB-S block copolymers is polyethylene, and a preferred polyethylene can be obtained from USI Chemicals Company under the trade designation Petrothene® Na601 (also referred to herein as PE Na601 or Na601).

Information received from U.S.I. Chemicals Company states that Na601 is a low molecular weight, low density polyethylene for use in the hot melt adhesives and coatings industries. U.S.I. further stated that Na601 has the following nominal values: (1) a Brookfield viscosity of 8500 mPa·s (cP) at 150ºC and 3300 at 190ºC when measured according to ASTM D 3236, (2) a density of 0.903 g/cm³ when measured according to ASTM D 1505, (3) an equivalent melt index of 2000 g/10 min when measured according to ASTM D 1238, (4) a ring and ball softening point of 102ºC when measured according to ASTM E 28; (5) a tensile strength of 5.7 kN/m² (850 pounds per square inch) when measured according to ASTM D 638; (6) an elongation of 90% when measured according to ASTM D 638; (7) a shear modulus TF (45000) of -34ºC; and (8) an indentation hardness of 3.6 (tenths of a mm) at 25ºC (77 degrees Fahrenheit).

The Na601 is believed to have a number average molecular weight (Mn) of about 4600, a weight average molecular weight (Mw) of about 22400, and a Z average molecular weight (Mz) of about 83300. The polydispersity of the Na601 (Mw/Mn) is about 4.87.

where Mn is given by the formula:

Mw = Sum [(n) (MW)]/Sum (n)

and Mw is calculated by the formula:

Mw = Sum [(n) (MW)²]/Sum [(n) (MW)]

and MZ is calculated by the formula:

Mz = Sum [(n) (MW)3]/Mz - Sum [(n) (MW)2]

is calculated, in which

MW = the different molecular weights of the individual molecules in a sample and

n = the number of molecules in the given sample that have a given molecular weight MW.

Blending polyolefins with the S-I-S and S-B-S block copolymers followed by melt blowing the blend has to date proved unsatisfactory in that the blends appear to be incompatible. However, a good material for blending with the S-I-S block copolymers is poly(alphamethylstyrene) and a preferred poly(alpha-methylstyrene) can be obtained from Amoco under the trade designation 18-210.

Preferably, the fibrous nonwoven gatherable web 50 portion of the nonwoven elastic web 52 made by the method of the present invention may be formed from any gatherable material that can be formed into a fibrous nonwoven gatherable web 50. For example, the fibrous nonwoven gatherable web 50 could be formed from a blend of a nonelastic material with an elastic material, one or more nonelastic materials, or a blend of one or more elastic materials with two or more nonelastic materials. Preferably, the fibrous nonwoven gatherable web 50 is formed from a fiber-forming, meltblown or cospun nonelastic gatherable material. Exemplary fiber-forming materials for use in forming the fibrous nonwoven gatherable web are polyester materials, polyolefin materials, or blends of one or more polyester materials with one or more polyolefin materials. An exemplary fiber-forming polyester material is polyethylene terephthalate. An exemplary fiber-forming polyolefin material is polypropylene. Preferred polypropylene materials can be obtained from the Himont Company under the trade designation PC 973 and PF 301.

Typical properties of Himont PC-973 polypropylene quoted by Himont are a density of about 0.900 g/cm3 measured according to ASTDM D 792, a melt flow rate of 35 g/10 min obtained according to ASTM D 1238, Condition L, a tensile strength of about 29.6 kN/m2 (4300 pounds per square inch (psi)) measured according to ASTM D 638; a flexural modulus of about 1.25 MN/m² (182,000 psi) measured in accordance with ASTM D 790, B and a Rockwell hardness, R scale, of 93 measured in accordance with ASTM D 785 A. The PC-973 is believed to have a number average molecular weight (Mn) of about 40,100, a weight average molecular weight (Mw) of about 172,000 and a Z average molecular weight of about 674,000. The polydispersity (Mw/Mn) of the PC-973 is about 4.29.

If the gatherable fabric 50 is to be separated from the elastic fabric 22 after it has been gathered, it is preferred that the gathered fabric 50 be capable of substantially returning to its gathered state after it has been separated from the elastic fabric 22. It is presently believed that in most embodiments, the gathered state (i.e., configuration) exhibited by the fibrous nonwoven gatherable fabric 50 after it has been separated from the fabric 22 is slightly longer in the direction of gathering (i.e., machine direction) as compared to the length of the same fabric length 50 when the fabric 50 is releasably joined to the elastic fabric 22. In other words, the fabric 50 stretches slightly in the direction of gathering after it has been separated from the fabric 22. Accordingly, the gathered, relaxed, non-prestressed Length of the severed fabric 50 slightly greater than or equal to the gathered, relaxed, non-prestressed length of the same fabric dimension 50 while connected to the elastic fabric 22.

In a particular embodiment of the present invention, the nonwoven elastic composite fabric 52 is comprised of a fibrous nonwoven elastic fabric 22 bonded to a gatherable fibrous nonwoven fabric 50. The nonwoven elastic composite fabric 52 of this embodiment differs from the nonwoven elastic composite fabric 52 of the previously described embodiments in that the bonding of the two fabrics 22 and 50 of the nonwoven elastic composite fabric 52 is accomplished without the application of heat and/or pressure during the bonding step, yet is stronger than the bond achieved by interlocking the fibers of the nonwoven gatherable fabric 50 with the fibers of the nonwoven elastic fabric 22 during formation of the fabric 50 on the fabric 22. In this particular embodiment, the fibrous nonwoven elastic web 22 is formed from an adhesive elastomeric material such that the fibrous nonwoven elastic web 22 is adhesive after formation. The adhesive fibrous nonwoven elastic web 22 is formed by melt blowing the web 22 onto the porous collection belt 14. Optionally, an adhesive nonwoven elastic foraminous film (not shown) may replace the adhesive fibrous nonwoven elastic web 22. Thereafter, the adhesive fibrous nonwoven elastic web 22 is stretched to a stretched length of at least one and one-quarter, that is, at least about 125% of its relaxed, unbiased length by the combined action of the rollers 20 and 26 and 30 and 32, preferably to a length of from about 150% of the relaxed, unbiased length to about 700% or more of the relaxed, unbiased length of the adhesive fibrous nonwoven web 22.

After the adhesive, fibrous, non-woven, elastic fabric 22 has been stretched, it is passed through the second porous Catch belt 36 to the nip or nip 42 between the rotating roller 40 and the rotating nip roller 44. As the web 22 is carried along by the second porous catch belt 36, the fibrous nonwoven gatherable web 50 is formed directly on the upper surface of the adhesive web 22 by either a conventional meltblowing or spunbonding process or by any other conventional process which can be used to form a fibrous nonwoven gatherable web 50, such as, for example, a conventional carding apparatus for forming a carded web. As was the case with the previously discussed embodiments, the adhesive fibrous nonwoven elastic web 22 is maintained in its stretched, pre-tensioned length during formation of the fibrous nonwoven gatherable web 50 by appropriately adjusting the peripheral surface speed of the rollers 40 and 44 with respect to the peripheral speed of the rollers 30 and 32. As a result of the fact that the fibrous nonwoven elastic web 22 is adhesive after its formation, an improved bond (as compared to bonding the two webs together by hooking alone) of the adhesive fibrous nonwoven elastic web 22 to the fibrous nonwoven gatherable web 50 is achieved by adhesion of the two webs 20 and 50 to each other during formation of the fibrous nonwoven gatherable web 50 on the upper surface of the fibrous nonwoven elastic web 22. This results in the simultaneous formation and bonding of the fibrous nonwoven gatherable web 50 to the fibrous nonwoven elastic web 22. While any adhesive elastomeric material may be used in forming the adhesive fibrous nonwoven elastic web 22 of this embodiment, a preferred adhesive elastomeric material is an AB-A' elastomeric block copolymer, wherein A and A' are each thermoplastic polystyrene end blocks and wherein B is a polyisoprene midblock. Triblock copolymer materials of this type are sometimes called SIS block copolymers and may be sold under the trade designation KRATON® D, for example, KRATON® D 1107, KRATON® D 1111, KRATON® D 1112 and KRATON® D 1117 can be obtained from Shell Chemical Company. Alternatively, a blend of a SIS block copolymer and poly(alpha-methylstyrene) can be used and

The materials that can be used to form the fibrous nonwoven gatherable fabric 50 of this embodiment can include any of the materials listed above with respect to the fibrous nonwoven gatherable fabric 50. That is, the fibrous nonwoven gatherable material can be formed from any gatherable material that can be formed into a fibrous nonwoven gatherable fabric 50. For example, the fibrous nonwoven gatherable fabric 50 could be formed from a blend of non-elastic materials with an elastic material, one or more non-elastic materials, or a blend of one or more elastic materials with two or more non-elastic materials. Preferably, the fibrous nonwoven gatherable web 50 is formed from a fiber-forming, meltblown or spunbondable, nonelastic gatherable material. However, the fibrous nonwoven gatherable web 50 may be formed by applying a carded web to the surface of the fibrous nonwoven elastic web 22 or by any other method that may be used to form a fibrous nonwoven gatherable web 50 on the surface of the web 22. Exemplary fiber-forming materials for use in forming the fibrous nonwoven gatherable web 50 are polyester materials, polyolefin materials, or blends of one or more polyester materials with one or more polyolefin materials. An exemplary fiber-forming polyester material is polyethylene terephthalate. An exemplary fiber-forming polyolefin material is polypropylene. Preferred polypropylene materials can be obtained from Himont Company under the trade designations PC 973 and PF 301.

In some situations, it may be desirable to incorporate individual particles of one or more solid materials into one or both of the fabrics 22 and 50 during formation of the fabrics 22 and 50 For example, it may be desirable to incorporate one or more fibers, such as cotton fibers, wood pulp fibers, polyester fibers, or other particulate material, into one or both of the webs 22 and 50 during their formation. This can be accomplished by using conventional co-forming equipment in conjunction with the meltblowing or co-spinning equipment 12 and/or 48. Such co-forming equipment is well known to those skilled in the art and is generally illustrated by the apparatus disclosed in U.S. Patent 4,100,432 to Anderson.

After the fibrous nonwoven gatherable web 50 has been formed on the upper surface of the fibrous nonwoven adhesive elastic web 22 and simultaneously bonded thereto, the composite nonwoven elastic web 52 is passed through the rollers 40 and 44, which for the reasons stated above do not need to be heated nor apply any excessive pressure to the composite elastic web 52. Thereafter, the stretching and prestressing force on the adhesive nonwoven elastic web 22 is released to relax and contract the nonwoven elastic web 52. Since the fibrous nonwoven gatherable fabric 50 is bonded to the surface of the adhesive fibrous nonwoven elastic fabric 22 while the adhesive fibrous nonwoven elastic fabric 22 is stretched, the relaxation and contraction of the nonwoven adhesive composite fabric results in the fibrous nonwoven gatherable fabric 50 being entrained, contracted and thereby gathered into a soft woven or matted fabric 50 bonded to the surface of the elastic fabric 22.

EXAMPLE I

A fibrous, nonwoven, elastic fabric previously formed by melt blowing a blend of 60 wt.% of an A- B-A' block copolymer having polystyrene A and A' end blocks and a poly(ethylene-butylene) "B" middle block (obtained from Shell Chemical Company under the trade designation KRATON® GX 1657) and 40 wt.% of a polyethylene (obtained from USI Chemical Company under the trade designation PE Na601) was provided in rolled form. Preliminary meltblowing of the fibrous nonwoven elastic web was accomplished by extruding the material mixture through a meltblowing die having thirty extrusion capillaries per linear inch of die tip. The capillaries each had a diameter of about 0.037 cm (0.0145 inches) and a length of about 0.287 cm (0.113 inches). The mixture was extruded through the capillaries at a rate of about 0.52 g per capillary per minute at a temperature of about 313°C (595 degrees Fahrenheit).

The extrusion pressure applied to the mixture was measured in the capillaries to be 503 N/m² (73 pounds per square inch). The nozzle tip location was adjusted to be located about 0.229 cm (0.090 inches) inward from the plane of the outer surface of the air plates forming the forming air gaps on each side of the capillaries. The air plates were adjusted so that the two forming air gaps, one on each side of the extrusion capillaries, formed air gaps of about 0.170 cm (0.067 inches). The forming air for meltblowing the mixture was supplied to the air gaps at a temperature of about 316°C (600 degrees Fahrenheit) and at a pressure of about 27.6 N/m² (4 pounds per square inch). The meltblown fibers thus formed were blown onto a forming belt which was approximately 38 cm (15 inches) from the die tip.

Later, the fibrous nonwoven elastic fabric thus formed was unrolled and stretched in the machine direction (MD) by applying a pulling, i.e., prestressing force, and a fibrous nonwoven gatherable fabric was formed on the surface of the elastic fabric by melt blowing polypropylene (obtained from Himont Company under the trade name PC 973) as microfibers on the upper surface of the fibrous nonwoven elastic fabric while the fibrous nonwoven elastic fabric was kept at its stretched length.

Meltblowing of the fibrous nonwoven gatherable polypropylene web was accomplished by extruding the polypropylene through a meltblowing die having thirty extrusion capillaries per linear inch of die tip. The capillaries each had a diameter of about 0.037 cm (0.0145 inches) and a length of about 0.287 cm (0.113 inches). The polypropylene was extruded through the capillaries at a rate of about 0.38 g per capillary per minute at a temperature of about 310ºC (590 degrees Fahrenheit). The extrusion pressure exerted on the polypropylene was measured in the capillaries to be 200 N/m² (29 pounds per square inch). The die tip location was adjusted to be approximately flush with the plane of the outer surface of the air plates forming the forming air gaps on each side of the capillaries. The air plates were adjusted so that the two forming air gaps on each side of the extrusion capillaries formed air gaps of approximately 0.038 cm (0.015 inches). The forming air for melt blowing the polypropylene was supplied to the air gaps at a temperature of approximately 316°C (600 degrees Fahrenheit) and at a pressure of approximately 27.6 N/m² (4 pounds per square inch). The melt blown microfibers thus formed were melt blown directly onto the upper surface of the fibrous nonwoven elastic web which was positioned approximately sixteen inches from the die tip. Due to these processing conditions, the viscosity of the polypropylene was about 2 Pas (20 poise) and polypropylene microfibers were formed on the surface of the fibrous nonwoven elastic fabric with a very small diameter.

Next, the pulling prestressing force was reduced to allow the fibrous nonwoven elastic web to contract and gather the meltblown polypropylene web in the machine direction. The nonwoven elastic composite web that was formed had a bond between the layers that appeared to result from the entanglement of the individual fibers of the two webs with each other, since the webs were not otherwise bonded by either adhesives or heat bonding.

Samples of the fibrous nonwoven elastic fabric itself and samples of the nonwoven elastic composite fabric were then stretched by an Instron Model 1122 extensometer which elongated each sample 100%, which is twice its unstretched length, and then the sample was allowed to return to an unstretched state. This procedure was then repeated three times and then each sample was elongated to break. Each sample was 5.08 cm (two (2) inches) wide and 12.7 cm (five (5) inches) long and the initial jaw spacing on the tester was set at 2.54 cm (one (1) inch). The samples were loaded lengthwise into the tester and elongated at a rate of 12.7 cm (five (5) inches) per minute. The machine direction data were obtained from samples having a machine direction length of five (5) inches (12.7 cm) and a cross direction width of two (2) inches (5.08 cm). The cross or cross machine direction measurements were obtained from samples having a cross machine direction length of five (5) inches (12.7 cm) and a machine direction width of two (2) inches (5.08 cm). The data obtained for the fibrous nonwoven elastic fabric are tabulated below in Table 111 and the data obtained for the composite elastic fabric are tabulated below in Table IV. TABLE III - FIBROUS NONWOVEN ELASTIC FABRIC Measurement Machine Direction Stretched Elongation Number Maximum TEA* cm/kg (inch-pounds) Maximum Load kg (lbs) Maximum Elongation cm (inches) Avg. Std. Dev. Average Std. Deviation to Break Transverse Measurements Stretched Elongation Factor Maximum TEA* cm/kg (inch-pounds) Maximum Load kg (pounds) Maximum Elongation cm (inches) Avg. Std. Dev. Average Std. Deviation to Break TABLE IV - NONWOVEN ELASTIC COMPOSITE FABRICS Machine Direction Measurement Stretched Elongation Number Maximum TEA* cm/kg (inch-pounds) Maximum Load kg (pounds) Maximum Elongation cm (inches) Avg. Std. Dev. Snatch Std. Dev. Transverse Measurement Stretched Elongation Factor Maximum TEA* cm/kg (inch-pounds) Maximum Load kg (pounds) Maximum Elongation cm (inches) Average Std. Def. to Break

Tables III and IV disclose the total energy absorbed in cm/kg (inch-pounds) and the peak (maximum) load in kg (pounds) experienced during each repetition and the magnitude of each peak (maximum) elongation in cm (inches) when the specimens were stretched during each repetition of the 100% elongation procedure and when the sample is elongated to break. It can be seen that the energy experienced to stretch the sample 100% in the machine direction at the peak load during such stretching is approximately the same for the fibrous nonwoven elastic fabric and the nonwoven elastic composite fabric. This is expected since the meltblown polypropylene fabric is gathered in the machine direction and generally requires little energy to be stretched in the machine direction. When stretched to break, the peak load for the nonwoven elastic composite fabric increased over 70%, indicating that the meltblown polypropylene fabric contributed to the strength of the nonwoven elastic composite fabric.

In the cross machine direction (TD), where the meltblown polypropylene is not gathered, the peak load for the initial elongation of the nonwoven elastic composite fabric is over 60% greater than the peak load for the fibrous nonwoven elastic composite fabric. This indicates that the meltblown polypropylene fabric contributes to the strength of the nonwoven elastic composite fabric even at low elongations. In addition, the peak total energy absorbed by the nonwoven elastic composite fabric represents a 50% increase over that of the fibrous nonwoven elastic composite fabric at the first elongation and then actually decreases at subsequent elongations. This indicates that the meltblown polypropylene fabric was significantly broken (torn) during the first elongation and no longer contributes to the total energy of the composite fabric.

It was observed that the "breathability" of the nonwoven elastic composite fabric was still good compared to the "breathability" of the fibrous nonwoven elastic fabric. In addition, because of the thin web of meltblown polypropylene microfibers applied to the surface of the fibrous nonwoven elastic fabric, the composite fabric was more water repellent due to the water repellent properties of polypropylene. Furthermore, applying the thin web of meltblown microfibers to the surface of the meltblown nonwoven elastic fabric changed the rubbery feel of the fibrous nonwoven elastic fabric into a soft, comfortable feel.

EXAMPLE II

A fibrous nonwoven web previously formed by melt blowing a blend of 60 wt.% of an A-B-A' block copolymer having polystyrene "A" and "A'" end blocks and a poly(ethylene-butylene) "B" midblock (obtained from Shell Chemical Company under the trade designation KRATON® GX 1657) and 40 wt.% of a polyethylene (obtained from U.S.I. under the trade designation PE Na 601) was provided in rolled form.

The preliminary melt blowing of the fibrous nonwoven elastic web was accomplished by extruding the material mixture through a melt blowing die having thirty extrusion capillaries at 2.54 cm (inch) of the die tip. The capillaries were about 0.0368 cm (0.0145 inches) in diameter and about 0.287 cm (0.113 inches) long. The mixture was extruded through the capillaries at a rate of about 0.50 grams per capillary per minute at a temperature of about 570 degrees Fahrenheit. The extrusion pressure exerted on the mixture was measured in the capillaries to be 0.99 kN/m² (144 pounds per square inch). However, it is currently believed that this measurement was in error due to a defective pressure sensor. The nozzle tip location was adjusted to be located about 0.279 cm (0.110 inches) inward from the plane of the outer surface of the air plates forming the forming air gaps on each side of the capillaries. The air plates were adjusted so that the two forming air gaps, one on each side of the extrusion capillaries, formed gaps of about 0.279 cm (0.110 inches). The forming air for meltblowing the mixture was supplied to the air gaps at a temperature of about 323°C (614 degrees Fahrenheit) and at a pressure of about 27.6 N/m² (4 pounds per square inch). The meltblown microfibers were formed on a forming belt which is believed to have been approximately 40.64 cm (16 inches) from the nozzle tip. However, no measurement of this distance was actually made.

Later, the fibrous nonwoven elastic fabric thus formed was unrolled and stretched in the machine direction (MD) by applying a pulling, i.e., prestressing force, and a fibrous nonwoven gatherable fabric was formed on the surface of the elastic fabric by melt blowing polypropylene (obtained from Himont Company under the trade name PF 301) as microfibers on the upper surface of the fibrous nonwoven elastic fabric while the fibrous nonwoven elastic fabric was kept at its stretched length.

Meltblowing of the fibrous nonwoven gatherable polypropylene web was accomplished by extruding the polypropylene through a meltblowing die having thirty extrusion capillaries at 2.54 cm (inches) from the die tip. The capillaries each had a diameter of about 0.0368 cm (0.0145 inches) and a length of about 0.287 cm (0.113 inches). The polypropylene was extruded through the capillaries at a rate of about 0.75 grams per capillary per minute at a temperature of about 310°C (590 degrees Fahrenheit). The extrusion pressure exerted on the polypropylene blend was measured in the capillaries to be about 1.28 kN/m² (186 pounds per square inch). The nozzle tip location was adjusted so that it was located about 0.025 cm (0.010 inches) inward from the plane of the outer surface of the air plates forming the forming air gaps on each side of the capillaries. The air plates were adjusted so that the two forming air gaps, one on each side of the extrusion capillaries, formed air gaps of about 0.046 cm (0.018 inches). The forming air for melt blowing the polypropylene was supplied to the air gaps at a temperature of about 316°C (600 degrees Fahrenheit) and at a pressure of about 14 N/m² (2 pounds per square inch). The distance between the nozzle tip and the surface of the fibrous nonwoven elastic The length of the fabric on which the gatherable polypropylene fabric was formed was about 25.4 cm (10 inches). Because of these process conditions, the viscosity of the polypropylene was about 12.4 Pas (124 poise) and larger diameter meltblown microfibers were formed on the surface of the stretched fibrous nonwoven elastic fabric.

Next, the pulling, prestressing force was reduced to allow the fibrous nonwoven elastic web to contract and gather the meltblown polypropylene web in the machine direction. The nonwoven elastic composite web that was formed had a bond between the layers that appeared to result from the entanglement of the individual fibers of the two webs with each other, since the webs were not otherwise bonded by either adhesives or heat bonding.

Samples of this fibrous nonwoven elastic fabric itself and samples of the nonwoven elastic composite fabric were then stretched by an Instron Model 1122 extensometer which elongated each sample 100%, which is twice its unstretched length, and then the sample was allowed to return to an unstretched state. This procedure was then repeated 3 times and then each sample was elongated to break. Each sample was 5.1 cm (two inches) wide and 12.7 cm (5 inches) long and the initial jaw spacing on the tester was set at 2.54 cm (1 inch). The samples were placed lengthwise into the tester and elongated at a rate of 12.7 cm (5 inches) per minute. The machine direction data was obtained from samples having a machine direction length of 12.7 cm (5 inches) and a cross direction width of 5.1 cm (2 inches). The measurements in the cross or machine direction were obtained from samples having a cross direction length of 12.7 cm (5 inches) and a machine direction width of 5.1 cm (2 inches). The data obtained for the nonwoven elastic composite fabric formed in Example 2 are tabulated below in Table V.

Table V below illustrates that the 100% machine direction stretches required little energy or stress, while the total energy absorbed increased by about 7 times and the peak stress increased by about 3 times when the composite was stretched to break in the machine direction. In the cross direction, where the meltblown was not gathered, the initial 100% stretch absorbed about 3.5 times as much energy as the total energy absorbed to break and about 4 to 5 times as much energy as any of the subsequent 100% stretches. Further, the peak stress for the first cross direction stretch was about 40% higher than the peak stress for any of the subsequent cross direction stretches, including stretching to break. TABLE V - NONWOVEN ELASTIC COMPOSITE FABRICS Machine Direction Measurement Stretched Elongation Number Maximum TEA* cm/kg (inch-lbs.) Maximum Stress kg (lbs.) Maximum Elongation cm (inches) Avg Std. Dev. Std. Dev. Avg. until tearing Measurement in transverse direction Stretched Elongation factor Maximum TEA* cm/kg (inch-pounds) Maximum load kg (pounds) Maximum elongation cm (inches) Average Std. deflection to break

NOTES ON TABLES III, IV AND V

* = total energy absorbed

** = Average

*** = standard deviation

**** = Average of two measurements. From the third measurement, values of 13.294 (2.376) for the highest TEA, 0.559 (1.232) for the maximum load, and 14.247 (5.609) for the maximum strain were obtained. These values are believed to be incorrect because they differ so much from the values obtained from the other two measurements.

Unless otherwise specifically stated, the data reported in Tables III, IV and V (above) represent an average value obtained by taking five individual measurements for each machine direction measurement and three individual measurements for each transverse direction measurement.

The basis weight of the meltblown fibrous nonwoven elastic web used for Example I was 67.3 g/m² and the basis weight of the meltblown gatherable polypropylene web formed on the surface of the fibrous nonwoven elastic web of Example I was measured to be 12.2 g/m². The degree of relaxation or contraction of the nonwoven elastic web of Example I was about 54%.

This degree of relaxation of the composite was determined by taking a sample of the composite with a relaxed length of about 10.16 cm (4.0 inches) in the machine direction and stretching the sample in the machine direction until resistance to stretching the sample was noted by the gathered polypropylene, that is, just until the gathers in the polypropylene fabric were removed. At this point, the sample had been stretched from 10.16 cm (4.0 inches) to about 22.23 cm (8.75 inches) in the machine direction.

The basis weight of the fibrous nonwoven elastic fabric used in Example II was about 66.2 g/m² and the basis weight of the fibrous nonwoven gatherable polypropylene fabric meltblown onto the surface of the elastic fabric in Example II was measured to be about 21.4 g/m². The degree of relaxation or contraction of the nonwoven elastic composite fabric of Example II was determined to be about 42%. This degree of relaxation was determined by taking a sample of the composite having a relaxed length of about 30.48 cm (12 inches) in the machine direction and stretching the sample in the machine direction until resistance to stretching the sample by the gathered polypropylene was noted, that is, just until the gathers in the polypropylene fabric were removed. At this point, the sample had been stretched from 30.48 cm (12 inches) to approximately 52.58 cm (20.7 inches).

Upon observation of the relaxed, gathered composite nonwoven elastic web, it was observed that the meltblown polypropylene web exhibited a crinkled, gathered appearance with the lines of gathering or gathering generally transverse to the direction in which the fibrous nonwoven elastic web was stretched during formation of the meltblown polypropylene web on the surface of the fibrous nonwoven elastic web (i.e., cross machine direction). Interestingly, it was also observed that the fibrous nonwoven elastic web of the contracted and relaxed nonwoven elastic composite web exhibited gather lines which were generally parallel to the direction of stretching of the fibrous nonwoven elastic web during formation of the meltblown polypropylene contained on its surface (i.e., the gather lines of the fibrous nonwoven elastic web were generally parallel to the machine direction). Accordingly, the two web composites contained webs with intersecting gather lines which generally crossed at right angles. The formation of the gather lines in the fibrous nonwoven elastic web gatherable polypropylene fabric would be expected with respect to the gathering of that fabric in the machine direction. However, the formation of the gather or gather lines in the fibrous nonwoven elastic fabric and in particular the formation of gather or gather lines in the fibrous nonwoven elastic fabric which generally intersect at right angles with the gather or gather lines of the fibrous nonwoven gatherable polypropylene fabrics was unexpected.

A portion of the nonwoven elastic composite fabric having an approximate machine direction (MD) length of about 14.9 cm (5 and 7/8 inches) and an approximate cross direction (TD) dimension of about 11.4 cm (44 inches) was cut from the nonwoven elastic composite fabric and the shirred fibrous nonwoven meltblown polypropylene fabric was separated from the fibrous nonwoven elastic fabric. After the shirred fibrous nonwoven meltblown polypropylene fabric was separated from the fibrous nonwoven elastic fabric, the shirred fibrous nonwoven meltblown polypropylene fabric was observed to assume a relaxed machine direction dimension of about 17.78 cm (7 inches) and to maintain its cross direction dimension of about 11.43 cm (44 inches). Significantly, the fibrous nonwoven gathered fabric substantially retained its shirred or gathered structure in the machine direction. Moreover, the severed gathered polypropylene fabric was capable of being stretched in the machine direction after application of a stretching and prestressing force in the machine direction and returned to its substantially relaxed and unstretched and unstretched gathered dimension of 17.78 by 11.43 cm (7 inches by 44 inches) upon release of the stretching and prestressing force, i.e., contracted. For example, after stretching the sample of the shirred fibrous nonwoven polypropylene fabric from 17.78 by 11.43 cm (7 inches by 44 inches) in the machine direction (MD) to an extent where the gathers had been substantially smoothed out, the sample was measured and found to have a machine direction (MD) length of of about 24.13 cm (9½ inches) and a cross direction dimension (TD) of about 11.43 cm (4½ inches). When the stretching, prestressing force was released from the sample, it returned to a machine direction (MD) dimension of just over seven inches and a cross direction (TD) dimension of about 11.43 cm (4½ inches) within one minute. After repeating the stretching process, the sample assumed a machine direction (MD) dimension of 24.13 cm (9½ inches) and a cross direction (TD) dimension of about 11.43 cm (4½ inches). After terminating the second elongation and stretching force, the polypropylene fabric assumed a machine direction (MD) dimension of 17.94 cm (7 1/16 inches) and a cross direction (TD) dimension of about 11.43 cm (4½ inches) within one minute. This result was unexpected since polypropylene PF 301 was not expected to have elastic properties.

Other variations of the present process and the product formed by the process are possible. For example, two or more fibrous nonwoven gatherable webs 50 may be joined one on top of the other in a layered arrangement to provide additional thickness to the fibrous nonwoven gatherable web 50. Additionally, a fibrous nonwoven gatherable web 50 may be joined, either separably or in other ways discussed herein, to both surfaces of the fibrous nonwoven elastic web 22 to form a nonwoven elastic composite web having the following three sequences: fibrous nonwoven gatherable web/fibrous nonwoven elastic web/fibrous nonwoven gatherable web.

The three-web sequence wherein the fibrous nonwoven elastic web is disposed between two fibrous nonwoven gatherable webs is particularly preferred where the fibrous nonwoven elastic web 22 is formed from an adhesive elastomeric material as described above, since disposing the adhesive elastic web 22 between the two webs prevents the adhesive web 22 from coming loose when the web 52 is rolled up for storage on other parts. of the web 52. The three-web material can be formed by the process schematically illustrated in Fig. 3. This process is identical to the process schematically illustrated in Fig. 1 until the two-ply nonwoven elastic composite web 52 exits the rollers 40 and 42. Instead of passing to the nip or nip 54 between the rollers 56 and 58, the composite web thereafter passes through the nip or nip 78 between a rotating roller 80 and a rotating nip roller 82. The composite web 52 is then carried by a third porous catch belt 84 to the nip or nip 86 between a rotating nip roller 88 and a rotating roller 74. The porous collecting belt 68 moves over and is moved by the rollers 80 and 84 in the direction indicated by the arrows 92 in Fig. 3. The rotation of the rollers 80, 82, 88 and 90 is adjusted so that the peripheral surface speed of the rollers 80, 82, 88 and 90 is the same as the peripheral surface speed of the rollers 40 and 40. Accordingly, the fibrous nonwoven elastic web 22 is maintained at its stretched, pre-tensioned length as it is carried by the porous collecting belt 84.

While the nonwoven elastic composite web 52 is carried along by the porous collecting belt 84, a conventional meltblowing nozzle 94 (a conventional spinning nozzle or carding device may be used if desired) forms a second nonwoven gatherable web 96 on the other surface of the stretched fibrous nonwoven elastic web 22 by meltblowing microfibers 98 directly onto the stretched upper surface of the nonwoven elastic web 22. The materials that may be used to form the second gatherable web 96 may include any of the materials previously identified as being useful in forming the first fibrous nonwoven gatherable web 50. Particulate materials may also be incorporated into the web 96 as noted above with respect to webs 22 and 50. Then the second, fibrous, non-woven, gatherable web 96 may be heat bonded to the fibrous nonwoven elastic web 22 by the action of rollers 88 and 90 which are substantially equivalent to rollers 40 and 44. Heat bonding of the second fibrous nonwoven gatherable web 96 to the fibrous nonwoven elastic web 22 may be carried out within the same temperature ranges and within the same pressure ranges as set forth above with respect to heat bonding of the first fibrous nonwoven gatherable web 50 to the fibrous nonwoven elastic web 22. If desired, conventional sonic bonding techniques (not shown) may be substituted for the heat bonding step. Alternatively, if the fibrous nonwoven elastic web 22 is adhesive as described above, heat bonding the fibrous nonwoven gatherable web 96 to the fibrous nonwoven elastic web is not required because the second fibrous nonwoven gatherable web 96 is simultaneously formed on and bonded to the surface of the fibrous nonwoven elastic web 22.

If the separation of the gatherable fabric 96 from the elastic fabric 22 is accomplished in a later step, in another embodiment, the second fibrous nonwoven gatherable fabric 96 may be releasably bonded to the surface of the fabric 22 by interlocking the individual fibers of the fabric 96 with the individual fibers of the fabric 22 during formation of the fabric 96 on the surface of the fabric 98. In this embodiment, the fibrous nonwoven gatherable fabric 96 is simultaneously formed on and bonded to the fibrous nonwoven elastic fabric.

In any of these embodiments, improved bonding of the webs 50 and 96 to the web 22 can be accomplished by applying a coating of an adhesive material to the surface of the elastic web 22 prior to formation of the webs 50 and 96 on the stretched surface of the web 22. Applying such an adhesive coating to the surface of the web 22 can be easily accomplished in a conventional manner by the nip rollers 32 and 82. For example, the adhesive material can be applied to the surface of the rollers 32 and 82 in a conventional manner so that the rollers 32 and 82 transfer the adhesive to the surface of the web 22 as the web 22 passes through the nips 28 and 78. Alternatively, the adhesive can be applied to the surface of the web 22 in an array of dots and

After the bonding of the gatherable fabric 96 to the elastic fabric 22 has been accomplished, the prestressing force on the fabric 22 is released by passing the three-fabric composite 100 through the nip or nip 102 between two rotating nip rolls 104 and 106. The rotation of the rolls 104 and 106 is adjusted so that the peripheral surface speed of the rolls 104 and 106 allows the composite fabric 100 to relax and, as a result of its elastic properties, to contract to its relaxed, non-prestressed length. Relaxing and contracting the fabric 100 to its relaxed, non-prestressed length results in both fibrous nonwoven gatherable fabrics 50 and 96 being gathered by the relaxing and contracting of the fibrous nonwoven elastic fabric 22. Finally, the composite fabric 100 can be rolled up as illustrated at 108. Since the adhesive elastic fabric 22 is disposed between the fabrics 50 and 96, it does not stick to other parts of the composite fabric 100 during storage. This material can be used to form a variety of products, such as, for example, cloth products.

It should be noted that the three-web composite 100 discussed above with respect to an adhesive nonwoven elastic web 22 may be formed without using an adhesive material to form the web 22. In this case, the other methods of bonding the web 96 to the web 22, for example, fiber entangling, heat bonding, or sonic bonding, may be used.

Another variation of the present invention includes, as illustrated in the figures, gathering one or more of the gatherable fabrics 50 and 96 in the cross machine direction (TD) as opposed to the machine direction (MD). If gathering of the gatherable fabrics 50 and/or 96 in the cross machine direction (TD) is desired, additional arrangements for stretching and contracting the elastic fabric 22 in the cross direction are utilized. For example, FIG. 4 illustrates another embodiment of the present invention which avoids the requirement of forming the gatherable nonwoven elastic fabric 50 of the embodiment of FIG. 1 on the stretched, elongated surface of the nonwoven elastic fabric 22. In the embodiment of Fig. 4, the gathered nonwoven elastic fabric 50 is formed directly on the surface of a porous forming belt 110 which is itself extendible and contractible in the machine direction of travel as indicated by arrow 112. For example, the extendible and contractible porous containment belt 110 may be formed from a continuous weave of the nonwoven elastic fabric 22. Alternatively, the extendible and contractible porous containment belt 110 may be formed from a wire mesh belt 114, generally illustrated in Fig. 5. The wire mesh belt 114 may be formed from a plurality of substantially parallel springs 116 wound and extending in the machine direction, the springs 116 being connected to one another in the cross machine direction (TD) by a plurality of thin, generally parallel wires 118 extending in the cross machine direction (TD). The transverse wires 118 may be arranged very closely together so that when the wire cloth belt 114 is in a non-prestressed, retracted or contracted configuration, the transverse wires 118 are in contact with each other. Upon application of a pulling or prestressing force in the machine direction, the coiled springs 116 expand, that is, stretch in the machine direction and the thin transverse wires 118 separate from each other to form the porous collecting surface 110. This prestressed, stretched, extended arrangement is generally illustrated in Fig. 6.

Optionally, the wire mesh belt 114 may be formed of a plurality of substantially parallel springs wound and extending in the cross machine direction (TD), the springs being connected to one another in the machine direction (MD) by a plurality of thin, generally parallel wires extending in the machine direction (MD). This arrangement is illustrated by Figures 5 and 6 after rotating 90° and results in an arrangement by which the gatherable fabric 96 can be gathered in the cross machine direction (TD) as opposed to the machine direction (MD) as illustrated in the figures. If gathering of the gatherable fabric 96 in the cross direction is desired, additional conventional arrangements (not shown) for stretching and contracting the belt 114 in the cross direction replace the arrangement for stretching and contracting the belt 114 in the machine direction (MD) illustrated in the figures.

Returning to Fig. 4, it will be seen that movement of the extensible and retractable porous collection belt 110 in the machine direction 112 is accomplished by driving the belt 110 through rollers 120 and 122, which in turn are driven by a conventional drive mechanism (not shown). Also, for clarity, a conventional vacuum chamber disposed between the rollers 120 and 122 and beneath the lower bottom surface of the upper portion of the belt 110 is not shown. The vacuum chamber assists in retaining the web 22 on the upper surface of the belt 110. The extensible and retractable porous collection belt 110 passes through the nip 124 between a pair of rotating nip rollers 126 and 128. The nip 124 is adjusted so that the rollers 126 and 128 firmly grip the extendible and retractable or contractible porous collecting belt 110 without adversely affecting the belt 110. The rotation of the rollers 126 and 128 is adjusted so that the surface peripheral speed of the rollers 126 and 128 is substantially the same as the Surface peripheral speed of the rollers 120 and 122. The extendible and retractable or contractible porous collecting belt 110 also passes through the nip 130 between another pair of rotating nip rollers 132 and 134, the nip 130 being adjusted so that the rollers 132 and 134 tightly grip the porous collecting belt 110 without adversely affecting the porous collecting belt. The rotation of the rollers 132 and 134 is adjusted so that the peripheral surface speed of the rollers 132 and 134 is greater than the peripheral surface speed of the rollers 120 and 122. As a result of increasing the peripheral surface speed of the rollers 132 and 134 relative to the peripheral surface speed of the rollers 120 and 122, a longitudinal or machine direction (MD) biasing and stretching force is applied to the stretchable and contractible porous collecting belt 110 and the belt 110 is stretched in the area 136 to an elongated, prestressed length in the longitudinal direction. The degree of stretching of the porous collecting belt 110 occurring in the area 136 between the rollers 126 and 128 and the rollers 132 and 134 can be varied, for example, by varying the peripheral surface speed of the rollers 132 and 134 with respect to the peripheral surface speed of the rollers 126 and 128. For example, if the peripheral surface speed of the rollers 132 and 134 is about twice that of the rollers 126 and 128, the stretchable and retractable porous collecting belt 110 will be stretched to an extended, prestressed length of substantially about twice, i.e., about 200%, its retracted, unprestressed length. The stretchable and retractable porous collection belt 110 is stretched in the area 136 to a length that is at least about 125% of its contracted, non-biased and non-stretched length, to about 700 or more% of the retracted, non-biased and non-stretched length of the porous collection belt 110. In particular, it is preferred that the belt 110 be stretched in the area 136 to a stretched length of at least about 150% of its retracted, non-biased and non-stretched length.

While the stretchable and retractable porous collection belt 110 is in the stretched configuration in the surface 136, meltblown microfibers 138 formed by a conventional meltblowing nozzle 140 are meltblown onto the stretched surface of the porous collection belt 110. When the meltblown microfibers 138 are applied to the stretched porous collection belt 110, they entangle and hang together to form a continuous, fibrous, nonwoven, gatherable web 96. The entangled, continuous, fibrous, nonwoven, gatherable web 96 is guided by the porous collecting belt 110 through the nip 130 and on to a nip formed between the rotating roller 120 and a rotating nip roller 144. The surface peripheral speed of the rotating nip roll 144 is adjusted to be substantially the same as the surface peripheral speed of the rotating roll 120 and the rolls 122 and 126 and 128. Because the surface peripheral speed of the rolls 144 and 120 is substantially the same as the surface peripheral speed of the rolls 122 and 126 and 128, the stretching force is removed from the external porous collecting belt 110 and the belt 110 is retracted, i.e., allowed to contract to its contracted, non-prestressed length as a result of its contractile properties. Relaxing and contracting the porous collection belt 110 to its contracted, non-biased length results in the fibrous, non-woven, gatherable web 96 being formed on the surface of the belt 110 while the belt 110 was maintained in its stretched configuration, being entrained and drawn back onto and thus gathered onto the upper surface of the receding porous collection belt 110. Gathering of the fibrous, non-woven, gatherable web 96 accordingly occurs in the area 146 between the roller pairs 132 and 134 and 120 and 144.

After retracting and contracting the porous collection belt 110, the fibrous, non-woven, gatherable fabric 96 can be rolled up on a supply roll 148 for storage and shipping. For the reasons previously stated, the rotational speed of the supply roll 148 should be controlled so that the gathered fibrous nonwoven web 96 is stored in a substantially unstretched condition. This can be accomplished by adjusting the rotational speed of the roll 148 so that the peripheral surface speed of the roll 148 is substantially equal to or only slightly greater than the peripheral surface speed of the rolls 120 and 144.

In the event that a three-layer composite fabric is formed as illustrated in Figure 3, it may be desirable to separate the two outer gathered nonwoven fabrics from the elastic nonwoven fabric. If so, the fibrous nonwoven gathered fabrics 50 and 96 are separated from the fibrous nonwoven elastic fabric 22 by passing the fabric 50 through the nip 150 between two rotating nip rolls 152 and 154 and passing the fabric 96 through the nip 156 between two rotating nip rolls 158 and 160. The fabrics 50 and 96 are then rolled up for storage and later used on their respective supply rolls 162 and 164. For the reasons previously stated, care should be taken when winding the gathered nonwoven fabrics 50 and 96 to ensure that the fabrics 50 and 96 are supported on the rollers 162 and 164 in an unstretched or substantially unstretched manner. This can be accomplished by rotating the rollers 162 and 164 such that the peripheral surface speed of the roller 162 is equal to or only slightly greater than the peripheral surface speed of the rollers 152 and 154, and such that the peripheral surface speed of the roller 164 is equal to or only slightly greater than the peripheral surface speed of the rollers 158 and 160. After the separation of the fabrics 50 and 96, the fibrous, non-woven, elastic fabric 22 passes through the nip 166 between the two rotating nip rolls 168 and 170 and is wound onto a feed roll 172.

While in the specific examples discussed herein it has been generally stated that the fibrous nonwoven gatherable webs 50 and 96 were formed using a conventional meltblowing nozzle and meltblowing process, conventional spinning nozzles and spinning processes can be substituted for the meltblowing nozzles and processes, and it is intended that the scope of the invention include materials formed by replacing the meltblowing nozzles and processes 48 and 94 with spinning nozzles and processes or any other devices and processes for forming a nonwoven gatherable web. In the event that either or both of the meltblowing nozzles or processes 48 and 94 have been replaced with co-spinning nozzles and processes, the bonding of the gatherable web(s) 50 and, if applicable, 96 to the fibrous nonwoven elastic web 22 as noted above should be accomplished by inter-web adhesion (if an adhesive elastomeric material is used to form the web 22), by heat bonding or sonic bonding, and/or by applying an adhesive to the surface(s) of the web 22 prior to formation of the web(s) 50 and 96 thereon. These bonding processes should be used with co-spun gatherable webs because the fibers of co-spun gatherable webs do not readily entangle with the fibers of the web 22. If the joining of one or more of the fabrics 50 and 96 to the fabric 22 is to be accomplished by heat bonding (whether the fabrics 50 and 96 are spun together, meltblown, or formed by other methods), care should be taken to allow the fabric 22 to relax and contract substantially to an unstretched, non-prestressed state or configuration as soon as practical after the heat bonding step has taken place, since it is believed that the nonwoven elastic fabric 22 will lose its elasticity if held above its softening point for a significant period of time. This loss of elasticity may result from the cooling of the elastic fabric 22 "setting" while in the stretched configuration. if it is held in the expanded configuration for a considerable period of time after heat bonding.

Claims (33)

1. A process for producing a non-woven elastic composite fabric comprising a non-woven elastic fabric bonded to a fibrous non-woven gathered fabric, comprising the step of: (a) Providing a non-woven elastic fabric, characterized in that it further comprises the following steps: (b) stretching the nonwoven elastic fabric from at least about 125% of the relaxed length of the nonwoven elastic fabric to about 700% of the relaxed length of the nonwoven elastic fabric; (c) forming a fibrous nonwoven gatherable fabric directly on a surface of the stretched nonwoven elastic fabric and bonding the stretched fibrous nonwoven gatherable fabric to the stretched nonwoven elastic fabric to form a nonwoven elastic composite fabric; and (d) relaxing the non-woven elastic composite fabric to gather the fibrous non-woven gatherable fabric. 2. A method according to claim 1, characterized in that the non-woven elastic fabric is an adhesive non-woven elastic fabric and the non-woven elastic composite fabric is produced by forming a fibrous, non-woven gatherable fabric is formed directly on a surface of the stretched non-woven elastic fabric and simultaneously bonding the non-woven elastic fabric to the surface of the stretched non-woven elastic fabric, wherein the bonding of the sticky non-woven elastic fabric to the fibrous non-woven gatherable fabric is achieved by adhesion of the two fabrics to each other during the formation of the fibrous non-woven gatherable fabric on the surface of the stretched fibrous non-woven elastic fabric. 3. A method according to claim 1, characterized in that the non-woven elastic composite fabric is formed by forming a fibrous non-woven gatherable fabric directly on a surface of the stretched non-woven elastic fabric and simultaneously bonding the fibrous non-woven gatherable fabric to the surface of the stretched non-woven elastic fabric, wherein the bonding of the non-woven elastic fabric to the fibrous non-woven gatherable fabric is achieved by hooking the individual fibers of the fibrous non-woven gatherable fabric to the non-woven elastic fabric during the production of the fibrous non-woven gatherable fabric on the surface of the stretched non-woven elastic fabric. 4. The method of claim 1, 2, or 3, characterized in that the step of providing the nonwoven elastic web comprises forming a fibrous nonwoven elastic web from meltblown microfibers. 5. A method according to claim 1, 2 or 3, characterized in that the step of providing the non-woven elastic fabric comprises providing a foraminous elastic film. 6. The method of claim 1, characterized in that the step of forming the fibrous nonwoven gatherable web comprises forming a fibrous nonwoven gatherable web on meltblown microfibers. 7. The method of claim 1 or 2 and 4, characterized in that the step of forming the fibrous nonwoven gatherable fabric comprises forming a fibrous nonwoven gatherable fabric from spun-together microfibers. 8. The method of claim 1, characterized in that the step of forming the fibrous nonwoven gatherable web comprises forming a carded web. 9. A method according to claim 1, characterized in that the step of bonding the fibrous non-woven gatherable fabric to the non-woven elastic fabric is achieved by heat bonding. 10. The method of claim 9, characterized in that the step of heat-bonding the fibrous nonwoven gatherable fabric to the nonwoven elastic fabric is accomplished by heat-bonding within a temperature range of about 50°C below a melting temperature of a material used to form one of the fabrics to about the melting temperature of a material used to form one of the fabrics. 11. Method according to claim 3 and 4, characterized in that the bonding is achieved solely by interlocking the individual fibers of the fibrous, non-woven, gatherable fabric with the individual fibers of the fibrous, non-woven, elastic fabric made of meltblown microfibers. 12. Method according to claim 3 and 5, characterized in that the bonding is achieved solely by hooking the individual fibers of the fibrous, non-woven, gatherable fabric with the holes in the holey, non-woven, elastic film. 13. A method according to any one of claims 1 to 12, characterized in that the non-woven elastic fabric comprises elastomeric fibers formed from a material selected from the group consisting essentially of A-B-A' block copolymers, wherein A and A' are each a thermoplastic polymer endblock comprising a styrene portion, and wherein A may be the same thermoplastic endblock as A' and wherein B is an elastomeric polymer midblock selected from the group consisting of poly(ethylenebutylene), polyisoprene or polybutadiene. 14. A method according to any one of claims 1 to 12, characterized in that the non-woven elastic fabric comprises elastomeric fibers formed from a material selected from the group consisting essentially of blends of one or more polyolefins with S-EB-S block copolymers, wherein "S" is selected from the group consisting of polystyrene and polystyrene homologous compounds and "EB" is poly(ethylene butylene). 15. A method according to any one of claims 1 to 12, characterized in that the non-woven elastic fabric comprises elastomeric fibers formed from a material consisting essentially of blends of poly(alpha-methylstyrene) with S-I-S block copolymers, wherein "S" is selected from the group consisting of polystyrene and polystyrene homologous compounds and "I" is polyisoprene. 16. The method according to claim 14, characterized in that the polyolefin is selected from the group consisting of at least one polymer, including copolymers, selected from the group consisting of ethylene, propylene and butene. 17. Process according to claim 16, characterized in that the polyolefin is polyethylene. 18. The method of claim 6, characterized in that the fibrous nonwoven gatherable fabric comprises inelastic meltblown microfibers. 19. The method of claim 7, characterized in that the fibrous, non-woven, gatherable fabric comprises inelastic, spun-together microfibers. 20. The method of claim 18 or 19, characterized in that the fibrous, non-woven, gatherable fabric comprises inelastic microfibers selected from the group consisting of polyester microfibers, polyolefin microfibers or mixtures of one or more polyester microfibers with one or more polyolefin microfibers. 21. The method according to claim 20, characterized in that the polyester microfibers comprise polyethylene terephthalate microfibers. 22. The method of claim 20, characterized in that the polyolefin microfibers comprising the fibrous, nonwoven, gatherable fabric comprise polypropylene microfibers. 23. The method of claim 2, characterized in that the tacky fibrous nonwoven elastic fabric comprises tacky meltblown elastomeric microfibers formed from a material selected from the group consisting essentially of (a) ABA' block copolymers, wherein "A" and "A'" are thermoplastic polymer endblocks selected from the group consisting of polystyrene or polystyrene homologous compounds, and B is an elastomeric polymer center block consisting of polyisoprene. 24. The method according to claim 23, characterized in that A and A' are selected from the group consisting of polystyrene. 25. The method of claim 23, characterized in that the step of forming the fibrous nonwoven gatherable web comprises forming a fibrous nonwoven gatherable web of meltblown microfibers on the surface of the fibrous nonwoven gatherable web. 26. A process for producing a gathered non-woven fabric having elastic properties, comprising the following step: (a) Providing an expandable and contractible mold surface characterized in that it further comprises the following stages: (b) stretching the mold surface from at least about 125% to about 700% of its unstretched length; (c) forming a fibrous nonwoven gatherable web directly on the stretched mold surface to releasably bond the fibrous nonwoven gatherable web to the stretched mold surface; (d) gathering the forming surface to gather the fibrous, non-woven, gatherable fabric; and (e) separating the gathered fibrous nonwoven gatherable fabric from the gathered forming surface. 27. A method according to claim 26, characterized in that the stretchable and contractible molding surface is a non-woven elastic fabric having a relaxed, irregular and contracted length and a stretched, regular and elongated length; and the fibrous nonwoven gatherable fabric is formed directly on a surface of the nonwoven elastic fabric mold surface to releasably bond the fibrous nonwoven gatherable fabric to the surface of the nonwoven elastic fabric mold surface while maintaining the nonwoven elastic fabric mold surface in its stretched length, wherein the releasably bonding of the fibrous nonwoven gatherable fabric to the nonwoven elastic fabric mold surface is achieved by interlocking the individual fibers of the nonwoven gatherable fabric with the individual fibers of the fibrous nonwoven elastic fabric mold surface during the formation of the fibrous nonwoven gatherable fabric on the surface of the nonwoven elastic fabric mold surface. 28. The method of claim 27, characterized in that the step of providing the molding surface from the nonwoven elastic fabric comprises forming a nonwoven elastic fabric from meltblown microfibers. 29. The method of claim 26, characterized in that the step of forming the fibrous nonwoven gatherable web comprises forming a fibrous nonwoven gatherable web from spun-together microfibers. 30. The method of claim 26, characterized in that the step of forming the fibrous nonwoven gatherable web comprises forming a fibrous nonwoven gatherable web from spun-together microfibers. 31. A method according to any one of claims 26 to 30, characterized in that the gathered fibrous non-woven fabric comprises inelastic microfibers. 32. The method of claim 31, characterized in that the gathered nonwoven elastic fabric comprises inelastic, meltblown microfibers selected from the group consisting of inelastic polyester microfibers, inelastic polyolefin microfibers, or blends of one or more inelastic polyester microfibers with one or more inelastic polyolefin microfibers. 33. A method according to claim 31, characterized in that the gathered, non-woven, elastic fabric consists essentially of inelastic spun-together microfibers.