KR20000049044A - Elastic necked-bonded materials and methods of forming the same - Google Patents

Abstract

PURPOSE: A method of forming elasticized materials, more particularly, elastic neck-bonded laminates, and methods of making the same, are provided. CONSTITUTION: A method of forming a stretchable composite comprises: applying a polymeric precursor(26) to a first neckable material; neck-stretching the neckable material(12) to form a necked material; then treating the polymeric precursor(26) to form a polymeric tie layer(27) wherein the polymeric tie layer bonds to the necked material; and bonding an elastic sheet(32) to the polymeric tie layer wherein the neckable material recovers when stretched in the necked direction.

Description

Elastic Necked-Bonded Materials and Methods of Forming the Same

For example, polymeric nonwoven webs produced by nonwoven extrusion methods such as meltblowing methods and spunbonding methods are inexpensive with the product and its components so that the product is considered to be discarded after only one or several uses. Can be prepared. Examples of such products include diapers, tissues, wipes, clothing, mattress pads and feminine hygiene products. There is a continuing need for improved materials that are elastic, resilient, and flexible while still having a satisfactory touch. The problem with fulfilling these demands is that commercially viable elastic materials often feel rubbery.

Unpleasant tactile properties of elastic materials can be avoided by making laminates comprising elastic sheets and one or more inelastic sheets with a soft feel. However, nonwoven webs made from inelastic polymers with improved qualities such as, for example, polypropylene, are generally considered to be inelastic. Lack of elasticity generally limits these nonwovens to applications where elasticity is not required. Nevertheless, laminates of elastic and inelastic materials have been produced by adhering the inelastic material to the elastic material in such a way that the laminate can be stretched and recovered while still retaining the desirable qualities of the inelastic material. Elastic laminates comprising an elastic sheet and a soft inelastic material are typically included into the product such that the soft material comes into contact with human skin or forms the outermost portion of the product.

In one of the laminates described above, the inelastic material is connected to the elastic material while the elastic material is in the stretched state so that when the elastic material is relaxed, the inelastic materials are gathered between the points where they are bonded to the elastic material. . The resulting composite elastic material can be easily stretched to the extent that the nonelastic material gathered between the bonding points can stretch the elastic material. Examples of this type of composite material are disclosed, for example, in US Pat. No. 4,720,415 to Vander Wielen et al.

Other elastic laminates known in the art include those conventionally referred to as "neck bonded" materials. Neck bonded materials are generally made by joining an elastic member to an inelastic member while the inelastic member is narrowed or necked. Neck bonded laminates provide a stretchable material in the necked direction, which is also most commonly a transverse machine direction. Examples of neck bonded laminates are described in Morman's batch-assigned US Pat. Nos. 5,226,992 and 5,336,545. In addition, “reversibly necked material” includes materials that are stretchable to approximately pre-necked dimensions and that recover to substantially necked dimensions without the aid of additional material upon removal of the stretching force. The material is typically made by necking the material and treating the necked material, eg, heating and cooling the material to give the material a memory of the necked dimensions. Reversibly necked materials and methods for their preparation are disclosed in Mormon's batch assigned US Pat. No. 4,965,122.

Because of the nature of the elastic laminate manufacturing method as described above, there are a variety of elastic materials having the necessary properties for use in forming the elastic laminate structure. Similarly, there are various neckable materials suitable for use in forming the elastic laminate structure as well. However, due to the variety of elastic and neckable materials potentially used to make elastic laminates, there are certain combinations of elastic and neckable materials that have good physical properties but do not adhere well to other layers of the laminate. Accordingly, there is a need for neck bonded laminates having improved integrity, as well as desirable tackiness and elasticity, and methods for their preparation.

[Justice]

As used herein, the term “spunbonded fiber” refers to, for example, US Pat. No. 4,340,563 to Appel et al. And US Pat. No. 3,692,618 to Dorschner et al., US Pat. U.S. Patents 3,802,817, U.S. Pat. Refers to a small diameter fiber made by extruding molten thermoplastic material as a filament from a plurality of fine, generally circular capillaries of the spinneret such that the diameter of the extruded molten filament is then drastically reduced as described in patent 5,382,400. . The spunbond fibers are then generally cooled and solidified so that they are not tacky when they are deposited on the collecting surface. Spunbond fibers are generally continuous and have an average diameter (from at least 10 samples) of greater than 7 microns, more specifically about 10 to 40 microns.

As used herein, the term “meltblown fibers” means that the filaments of the molten thermoplastic material as molten yarn or filaments, through a plurality of fine, generally circular die capillaries, can be filaments up to the microfiber diameter thereof. Fibers produced by extruding into a stream of hot, converging high velocity gas (eg air), generally tapering to reduce the pressure. The meltblown fibers are then cooled and carried by the high velocity gas stream to be deposited on a collecting surface to form a web of randomly dispersed meltblown fibers. This method is disclosed, for example, in US Pat. No. 3,849,241 to Butin et al.

"Multilayer laminate" as used herein refers to a laminate having two or more layers, one of which is a nonwoven web. For example, some of the layers may be spunbond and some meltblown, such as, for example, spunbond / meltblown / spunbond (SMS) laminates and Brock, US Pat. No. 4,041,203, Collier. US Pat. No. 5,169,706, et al. US Pat. No. 5,145,727, Perkins et al. US Pat. No. 5,178,931, Perkins et al. Can be. The laminate is prepared by first depositing a spunbond fiber layer, followed by a meltblown fiber layer and finally another spunbond fiber layer, followed by bonding to form a laminate on a moving forming belt. Alternatively, the fibrous layers can be made separately, collected in rolls, and combined in separate bonding steps. The fabric is generally about 0.1 to about 12 ounces / yard ² (about 3.4 to about 400 g / m ² ), more specifically about 0.75 to about 3 ounces / yard ² (about 25 to about 100 g / m ² ) Has a basis weight of. Multilayer laminates may also have many different numbers of meltblown layers or multiple spunbond layers in many different forms and may include other materials such as fabric layers, films, or co-molded materials.

As used herein, the term "machine direction" or MD refers to the direction in which the neckable material is made. The term "lateral machine direction" or CD refers to a direction generally perpendicular to the MD.

The term "microfiber" as used herein refers to a small diameter fiber having an average diameter of about 100 microns or less, for example having an average diameter of about 0.5 microns to about 50 microns, or more specifically The fibers can have an average diameter of about 2 microns to about 40 microns.

As used herein, the term “ultrasonic coupling” refers to a method performed by passing a fabric between a sonic horn and an anvil roll, as illustrated, for example, in US Pat. No. 4,374,888 to Bornslaeger.

As used herein, “thermal point bonding” includes passing a web of fabric or fiber to be bonded between a heated bonding assembly, such as a heated calendar roll and a heated anvil roll. Calendar rolls, although not always, are generally patterned in such a way that the entire fabric is not bonded through their entire surface, and the Anvil rolls are generally smooth. As a result, various patterns of calendar rolls have been developed for functional as well as aesthetic reasons. One example of a pattern is a Hansen Pennings or "HP" pattern with about 30% bond area having about 200 bonds / square inch, as described in Hansen and Pennings, US Patent No. 3,855,046. to be. The new HP pattern roll has a square dot or pin bonding area where each pin has a lateral dimension of 0.038 inches (0.965 mm), a spacing between pins of 0.070 inches (1.778 mm) and a depth of engagement of 0.023 inches (0.584 mm). . The resulting pattern has a binding area of about 29.5%. Other representative dot bonding patterns are enlarged Hansen Pennings or “EHP” bonding patterns, which, when new, have a lateral dimension of 0.037 inches (0.94 mm), a pin spacing of 0.097 inches (2.464 mm) and 0.039 inches (0.991 mm) Create a 15% bond area with square fins with a depth of. Another representative dot bonding pattern, denoted as "714", is a rectangular pin with each side having a lateral dimension of 0.023 inches, spacing between pins of 0.062 inches (1.575 mm) and a depth of engagement of 0.033 inches (0.838 mm) when new. Has a bonding area. The resulting pattern has about 15% bonded area. Another common pattern is the C-Star pattern with about 16.9% binding area when new. The C-Star pattern has a "corduroy" design with transverse bars or shooting stars. Other common patterns include diamond patterns with about 16% bonded area with repeated and slightly offset diamonds and wire weave patterns with about 19% bonded area, which look similar to window screens. Typically, the bonding area% is less than 50% of the laminate area and preferably varies from about 10% to about 30% of the laminate area.

As used herein, the term "elastic" means that when a biasing force is applied, it is stretchable to an elongated and biased length that is at least about 160% of the unbiased relaxed length, and at least 55% of its elongation upon removal of the stretching force Refers to any material that is to be recovered. A hypothetical example is a one inch size sample of material that can be stretched to 1.60 inches or more and will recover to a length of 1.27 inches or less when stretched to 1.60 inches and released. Many elastic materials can be stretched at least 60%, for example 100% or more, of their relaxed length, many of which are substantially at their original relaxed length, eg their original, upon removal of the stretching force. The recovery is within 105% of the relaxed length.

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

As used herein, the term "recover" refers to the contraction of the stretched material at the end of the bias force after stretching of the material by application of the bias force. For example, if a material with an unbiased relaxed length of 1 inch is 60% stretched to a length of 1.6 inches by stretching, the material is 60% (0.6 inch) stretched and is 160% of the relaxed length. Have an elongated length. If this illustrated stretched material was retracted, i.e., recovered to a length of 1.2 inches after removal of the biasing and stretching forces, the material recovered about 66% (0.4 inches) of 0.6 inch elongation. Recovery can be expressed as [(maximum stretch length-final sample length) / (maximum stretch length-initial sample length)] × 100.

As used herein, the term "necking" or "neck stretching" interchangeably reduces the width of the nonwoven fabric by adjusting it to a desired amount in a direction perpendicular to the stretching direction, for example machine direction. Refers to the method of stretching the nonwoven fabric. Controlled elongation and necking can occur at low temperatures, at room temperature or higher, and are limited to the increase in overall dimensions in the direction of elongation to the elongation needed to break the woven fabric. When relaxed, the web shrinks toward its original dimension. This method is described in, for example, United States Patent Nos. 4,443,513, such as Meitner, United States Patent Nos. 4,965,122, Morman et al. Patent No. 5,244,482.

As used herein, the term "neckable material" refers to any material that can be necked, i.e., a material that can be shrunk beyond one dimension by a method such as, for example, stretching.

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

As used herein, the term “reversibly necked material” is stretched to its original pre-necked dimension in the necked direction and, upon removal of the stretching force, to substantially necked dimensions without assistance such as by an elastomeric sheet. Say stuff that can go back. Typically reversibly necked materials include necked materials that have been heated and cooled while under tension. Heating and cooling of the material while necking serves to impart memory of the necked state of the material.

As used herein, the term "neckdown" refers to the ratio determined by dividing the difference between the necked and unnecked dimensions of the neckable material and then dividing the difference by the unnecked dimension of the neckable material. Say. This ratio is then multiplied by 100.

As used herein, the term "sheet" means a film, foam or nonwoven web.

As used herein, the term "layer" refers to a polymeric material that may be continuous, for example a film, or may be a repeating or random pattern of discontinuous regions, for example, when supported on a support.

As used herein, the term "elastic neck bonded laminate" refers to a material having an elastic layer connected to the necked material. The elastic material may be connected to the necked material with intermittent points or regions or provide a complete coverage of the necked material. The elastic neck bonded laminate is elastic in a direction generally parallel to the neckdown direction of the necked material and may include one or more layers. For example, the elastic neck bonded laminate may have necked material connected to both sides thereof to form three layers of composite elastic neck bonded material having a structure of necked material / elastic material / necked material. Additional layers of elastic and / or necked material may be added. In addition, many combinations of layers of elastic materials can also be used.

As used herein, the term "polymer precursor" refers to a material that can be treated to form a polymer layer by polymerizing, curing, crosslinking, bonding, drying, or evaporating a solvent. However, the term "polymer precursor" does not exclude materials containing polymers. For example, often latex formulations contain polymers, but the applied latex formulations do not form a solid material until dry.

As used herein, the term "elastomer precursor" refers to a material that is not an elastomer upon application but can be treated to form an elastic layer by polymerizing, curing, crosslinking, bonding, drying, or evaporating the solvent. However, the term "elastomer precursor" does not exclude materials containing elastomers. For example, often latex formulations contain elastomers, but the applied latex formulations do not form an elastic material until dry.

[Summary of invention]

Applying a polymer precursor to the neckable material, necking the neckable material, and then treating the polymer precursor to form a tie layer directly attached to the necked material, and attaching the elastic sheet to the tie layer The above requirements are met by the elastic neck bonded laminate produced by the attaching step and the problems experienced by one of ordinary skill in the art have been overcome. The polymer precursor may comprise a thermoset material treated by heating or a latex treated by drying. In a further aspect, the polymer precursor may be applied to the neckable material in an amount sufficient to form a tie layer of about 1 to about 100 g / m ² . In addition, the polymer precursor may be applied to the neckable material before or during the necking. Preferably, the polymer precursor comprises an elastomeric precursor that, when treated, forms an elastomeric layer. In addition, the elastic sheet may be in contact with the polymer precursor prior to processing to form the tie layer. For example, the molten elastomer can be extruded directly on the precursor to form the elastic sheet and tie layer. Alternatively, the elastic sheets may be brought into contact with the tie layer and connected to them by heating and / or pressing.

In a further aspect of the invention, an elastic neck bonded laminate is applied to a polymer precursor to the necked material, followed by treating the polymer precursor to form a tie layer directly attached to the necked material, and the elastic sheet It can be prepared by the step of bonding to the tie layer. The polymer precursor may comprise a thermoset material treated by heating or a latex treated by drying. Preferably, the polymer precursor comprises an elastomeric precursor that forms an elastomeric polymer when processed. In addition, the polymer precursor may be applied in a sufficient amount to the neckable material to form an elastic tie layer of about 1 to about 100 g / m ² . In a further aspect, the elastic sheet may be in contact with the polymer precursor prior to processing to form the tie layer. For example, the molten elastomer can be extruded directly on the precursor to form the elastic sheet and tie layer. Alternatively, the elastic sheets may be brought into contact with the tie layer and connected to them by heating and / or pressing.

The present invention relates to a method for producing an elasticizing material. More specifically, the present invention relates to elastic neck-bonded laminates, and methods of making the same.

1 is a schematic of an exemplary method of making an elastic neck bonded composite material having a polymeric tie layer.

2 is a plan view of the neckable material under tension.

3 is a top view of the neckable material before tensioning and necking.

3A is a top view of the necked material.

3B is a plan view of the composite elastic neck bonded material while partially stretched.

4 is a schematic of an exemplary method of making an elastic neck bonded composite material having a polymer tie layer.

5 is a schematic of an exemplary method of making an elastic neck bonded composite material having a polymeric tie layer.

6 is a schematic of an exemplary method of making an elastic neck bonded composite material having a polymer tie layer.

7 is a plan view of a necked material having discrete patterned tie layers.

In one aspect of the invention, referring to FIG. 1, the neckable material 12 is released from the feed roll 14 and in the direction indicated by the associated arrow as the feed roll 14 rotates in the direction of the associated arrow. Move. One of ordinary skill in the art will appreciate that the neckable material 12 can be prepared by known nonwoven extrusion methods, such as meltblowing methods or spunbonding methods, without first being stored on a feed roll. . Polymer precursor 26 may be applied to the neckable material 12 before necking. The neckable material 12 is then necked to the desired width and the polymer precursor 26 is treated to form the polymer tie layer 27. An elastic material 32 is then connected to the tie layer 27 and the necked material 13 to form an elastic neck bonded laminate 44.

The polymer precursor has a tie layer 27 having an adhesion amount of about 1 to about 100 g / m ² , preferably about 2 to about 50 g / m ² , and even more preferably about 2 to about 20 g / m ² . It may be applied in an amount sufficient to provide. Preferred polymeric materials and their corresponding precursors are discussed in more detail herein below. The polymer precursor 26 may be applied to the neckable material 12 by one of a number of techniques known in the art for printing, coating or spraying a material on a sheet or fabric like surface. The polymer precursors 26 are wire woven coating bars, calendering, extrusion, spraying, direct gravure printing, knife-over-roll coating, floating-knife coating, reverse roll coating, rotating screen coating, transfer coating and flexo printing. It can be applied by a variety of methods, including but not limited to. In addition, the polymer precursor may be applied in one or successive applications. The polymer precursor can be applied directly or indirectly. For example, the precursor can be applied by coating the elastic sheet in a desired pattern and then compressing the elastic sheet and the necked material together.

Preferred methods of applying certain polymer precursors are dependent on factors known to those of ordinary skill in the art, such as the flow properties of the precursor, the desired thickness and gauge resistance of the coating, the linear velocity and surface properties of the material being coated. Will change. Flexo or direct gravure printing is preferred, since it is desirable to have a discontinuous layer of precursor applied to the neckable material, for example a patterned layer. In gravure, flexo and screen printing devices, the printed composition is transferred to a printing transfer surface containing the printed pattern and then the printing composition is transferred directly from the transfer surface to the support.

Referring to the embodiment of FIG. 1, the neckable material 12 is passed through a nip 18 of an S-roll type drive roll arrangement 16 produced by stacked drive rolls 20 and 22. The polymer precursor 26 is applied to the coating assembly 24, for example a material 12 neckable with a gravure print coater. Individual rolls of coating assembly 24 rotate to guide precursor 26 onto neckable material 12. The coater 24 is lightly compressed by pressing the polymer precursor 26 against the neckable material 12 in the final nip of the coating assembly 24 produced together with the roll 22 of the drive roll assembly 16. Is removed from.

Penetration of the polymer precursor typically occurs without the need for additional means to squeeze or drive the precursor into the neckable material. For example, although polyolefin nonwoven webs are predominantly hydrophobic, many latex formulations include surfactants that make the latex miscible with the nonwoven material and are therefore easily absorbed or absorbed into the web. However, if further penetration is desired, additional press roll arrangements may be provided to obtain the desired penetration. In addition, the composition of the precursor may be treated or the composition of the precursor may be varied, for example by corona treatment, to achieve the desired miscibility between the materials.

For porous neckable materials such as nonwoven webs, the depth at which precursor 26 penetrates the neckable material 12 affects the elasticity of the resulting neck bonded laminate. In general, the elasticity of the formed laminate decreases as the penetration of the precursor 26 increases. In addition, since the treated polymer precursor 26 will act as a tie layer, it is desirable to have a substantial portion of the polymer precursor located at or near the surface of the neckable material. In addition, the strike-through of the resulting polymers and precursors can degrade the soft hand of the neckable material. Therefore, the nip pressure must be tightly controlled during the unprocessed precursor forming the polymer tie layer. In most cases, a gap must be maintained between the rolls to ensure that the precursor does not significantly penetrate into the neckable material. However, penetration of the precursor near the surface is desirable when the tie layer is not sufficiently bonded to the necked material because the tie layer formed when processed will produce a material embedded in the neckable material. For example, in the case of a nonwoven material, a tie layer will surround the fibers in the web, thus providing a mechanical attachment to the web. Thus, it is preferable in this case that the precursor penetrates by at least 1 fiber thickness, preferably 2 to about 5 fiber thicknesses.

Penetration of the precursor into the neckable material may be limited or controlled by various means. For example, the neckable material can be treated immediately after addition to the neckable material to limit the extent to which the viscous precursor can be drawn into the neckable material. The neckable material may also include a barrier to further penetration of the precursor. For example, the neckable material may comprise a multilayer laminate, for example, SMS, having a meltblown layer therein that prevents unwanted penetration and osmotic penetration of the precursor. Meltblown nonwovens having a fiber diameter of less than 10 microns typically have very small pore structures that often prevent penetration of precursors. Alternatively, larger fiber diameter nonwovens with larger pore sizes may be treated with a release agent, such as fluorocarbons, or may include a repellent, which prevents penetration of the precursor into the fabric. See, US Pat. No. 5,441,056 to Weber et al., Which is incorporated herein by reference. In this regard, the neckable material produces layers of spunbond fibers in which one or more banks have been treated with a release agent or otherwise incorporated with a release agent, and at least a layer of untreated fibers on the release agent treated fiber with the last bank previously placed. It can be prepared using a plurality of spunbond banks to produce the. The multiple layers of spunbond fibers are then joined to form a cohesive web that can be necked. Thus, when the precursor is added to the neckable material, it will only penetrate the fibers without the release agent located on the top surface of the neckable material.

From the drive roll assembly 16, the neckable material 12 undergoes neck extension while being pulled by the press nip formed by the engagement roll arrangement 36. Since the peripheral linear velocity of the roll of the drive roll assembly 16 is adjusted to be less than the peripheral linear velocity of the engagement roll assembly 36, the neckable material 12 is between the drive roll assembly 16 and the engagement roll assembly 36. Receive seal from By adjusting the speed difference between the roll assemblies 16 and 36 and the distance between them, the neckable material 12 is tensioned to neck in the desired amount to form the necked material 13.

The neckable material 12 is necked before it reaches the processing apparatus 30, but the necked material 13 may be further necked upon heating. The distance between the drive roll assemblies 16 and 36 that causes the neckable material 12 to neck must be sufficient to achieve the desired neckdown. Referring to FIG. 2, the neckable material 12 is neck stretched between the first and second roll assemblies 16 and 36. However, the neckdown percentage increases as the neckable material moves from the first roll assembly 16 toward the second roll assembly 36. The neckable material 12 is necked while approaching the equilibrium, so that no further necking occurs in this regard without additional tension or heating. Preferably, the drive roll assemblies are spaced apart a sufficient distance to substantially approach the equilibrium. In addition, the precursor (not shown) is also treated at a point along the distance between the first and second roll assemblies 16 and 36 such that a tie layer is formed only after the neckable material has been necked in the desired amount. desirable.

The relationship between the original dimension of the neckable material 12 and its dimensions after tensioning and necking determines the approximate limit of elongation of the elastic neck bonded material 44. Since the necked material 13 is elongated in the transverse machine direction and can be returned to its pre-necked dimensions, the elastic neck bonded material 44 elongates generally in the same direction as the neckable material 12 is necked. It becomes possible.

For example, referring to Figures 3, 3A and 3B, where it is desirable to produce an elastic elastic neck bonded composite material up to 150% elongation, it is necessary, having a width "A", for example 250 cm, However, the width of the neckable material shown schematically in the dimensions of FIG. 3 is tensioned by force F and they are necked down to a "width B" of about 100 cm. The elastic precursor (not shown) is then treated to form an elastic tie layer (not shown). In addition, an elastic sheet having a width of approximately 100 cm is connected to the necked material and tie layer. The resulting composite elastic neck bonded material, which is not necessarily but schematically represented in the dimensions of FIG. 3B, has a width "B" of about 100 cm and an original 250 cm width "A" of neckable material for elongation of about 150%. Stretchable to (or as discussed above, the material is stretchable to 250% of its unbiased relaxed width). The elastic limitation of the continuous elastic tie layer and / or elastic sheet only needs to be as large as the desired maximum elongation of the composite elastic neck bonded material. However, it is typically desirable to use elastic materials that allow the necked material to easily stretch beyond its pre-necked dimensions.

The necked material 13 is liberated in a tensioned necked state while the polymer precursor 26 is being processed to form a layer 27 in intimate contact with the necked material 13. In this regard, because of the ability to penetrate into the neckable material 12 upon application of the precursor 26, treatment of the precursor 26 directly binds to the material and / or is at or near the surface of the necked material 13. It is important to note that it solidifies the fibers approximately to form a polymeric material that is attached to the necked material.

Treatment of the precursor 26 will vary with respect to the specific precursor and the mechanism by which the polymer tie layer 27 is produced. For example, the reaction may be triggered by various means such as infrared rays, ultrasonic waves, ultraviolet rays, X-rays, electron beams, or the like to generate a thermosetting material. It is contemplated that polymer precursors using these and / or other initiators used to produce miscible polymeric materials are suitable for use with the present invention. Nevertheless, the most common polymer precursors on the market typically include thermoset and latex formulations that are activated by heating or dried by heating or microwaves. Thus, although certain embodiments discussed herein relate to the use of thermal curing and / or latex formulations, the present invention is not limited to the use of such materials or methods of using them.

With reference to the particular embodiment illustrated in FIG. 1, precursor 26, such as a latex or thermoset formulation, may be treated by heating the applied precursor 26 in a treatment device 30, such as an oven. . If the treatment of the precursor 26 comprises heating, it heats the necked material, as described in Mormon's US Pat. No. 4,965,122, the entire contents of which are incorporated herein by reference to " reversibly necking. It can be noted that the "contained material" can be performed at the same time. In addition, the heating device may have multiple temperature control zones (not shown) such that the necking process is substantially completed in a predetermined amount prior to significant processing of the precursor.

Still referring to FIG. 1, the elastic sheet 32 is released from the feed roll 34 and fed into the nip 38 of the bond roll assembly 36 together with the necked material 13 and tie layer 27. The elastic sheet 32 is fed into the bond roll assembly with the necked material 13 such that the elastic sheet 32 is in intimate contact with the tie layer 27. The peripheral linear velocity of the elastic sheet supply roll 34 can be changed as needed. For example, the linear velocity of the feed roll 34 may be substantially the same as the linear velocity of the engagement roll assembly 36 such that elongation of the elastic sheet 32 does not occur.

The bond roll assembly 36 may be a patterned calendar roll 40 disposed with the smooth anvil roll 42. Alternatively, a smooth calendar roll can be used. It is further desirable to heat the laminated materials to a temperature sufficient to attach the tie layer 27 and elastic sheet 32 while in direct physical contact. The specific temperature and pressure required will vary depending on the particular elastic material selected. One or both of the calendar roll 40 and the anvil roll 42 may be heated, and the pressure between these two rolls may be adjusted by known methods to provide the desired temperature and bonding pressure. Various combination patterns may be used including, but not limited to, the above-mentioned patterns with respect to the dot pattern of the sinusoid and the dot combination. The bonding surface area on the composite elastic neck bonded material 44 can approach nearly 100% and can provide good elasticity to the elastic laminate material. Other methods can be used to connect the materials, such as, for example, ultrasonic welding, laser beams, high energy electron beams, and / or other methods known in the art.

The tie layer 27 attaches directly to the necked material 13, thus providing improved integrity for the formed neck bonded laminate. The integrity is further improved due to the ability to achieve better adhesion between the tie layer 27 and the elastic layer 32 when compared to the adhesion between the neckable material 13 and the elastic sheet 32. Can be. However, if the tie layer itself is elastic and does not significantly penetrate the neckable material, the elongation and recovery properties of the resulting neck bonded laminate are not significantly degraded. In addition, the use of elastic tie layers, due to the nature of the neck bonded material, will reduce the fracture of the bond area and / or the generation of high stress points within the laminate.

Although the use of an elastomeric precursor and an elastic tie layer is preferred, an inelastic polymer may be used as the tie layer. The polymer precursors may be produced on the necked or neckable material in a manner that does not significantly degrade the elasticity of the resulting laminate. For example, referring to FIG. 7, tie layer 27 may be created as a continuous section on necked material 13 or as closely spaced columnar points extending in a direction substantially perpendicular to the necked direction. have. Thus, when the neck stretched material is stretched in the machine direction, the tie layer extends substantially parallel to the machine direction. For example, referring to FIG. 7, tie layer 27 may include pillars of spaced polymer extending in the machine direction of necked material 13. This pattern still allows the fabric to stretch and recover in the necked direction. Preferably the pattern comprises less than about 70% of the surface area of a single side of the treated fabric.

Conventional drive means and other conventional apparatuses that can be used with the apparatus of FIG. 1 are known and are not illustrated in the schematic diagram of FIG. 1 for the sake of simplicity. In addition, it will be apparent to one skilled in the art that certain procedures may be varied in many respects without departing from the spirit and scope of the invention. For example, the neckable material may be fully necked and processed to remain in its necked state (eg, reversibly necked) before being wound onto the feed roll 14. As a further example, after treatment of the precursor and formation of the tie layer, an elastic sheet can be formed directly on the coated side of the neckable material, for example by extruding a molten elastomer film thereon (the entire contents of which are set forth herein). See U.S. Patent No. 5,514,470 to Haffner et al., Which is incorporated herein by reference .. The method of the present invention, in conjunction with other methods known in the art for producing stretchable materials in both transverse and machine directions. It can be further appreciated that it may be used (see Norman U.S. Patent No. 5,116,662, which is incorporated herein by reference in its entirety) For example, the peripheral linear velocity of the roll 34 may be determined by the roll assembly 36. It can be adjusted below the linear velocity of to stretch the elastic layer 32. This allows the resulting laminate to stretch in both the MD and CD directions.

Also, those skilled in the art will appreciate the neckable material 12, such as for example, a tenter frame or other direction expander arrangements that extend the neckable material 12 in other directions, such as, for example, the transverse machine direction. Other methods of tensioning may be used to bond the elastomeric material to the necked material so that the resulting composite elastic neck bonded material 44 is elastic in a direction generally perpendicular to the necking direction, for example in the machine direction. It can be seen that. The inelastic material may also be gathered before necking. In this case, the tensile force does not narrow the fabric to the gathered dimensions, but the fabric is narrower than the original pre-gathering dimensions of the fabric. "Necking" is intended to include a narrowing of the tension and the dimensions before gathering.

The neckable material 12 may be a knitted, coarse woven or nonwoven material such as a spunbond web, meltblown web, a eutectic web or a bonded carded web. If the neckable material is a nonwoven web, it may comprise microfibers. The neckable material can be any porous material that can be necked. The neckable material 12 can be made from fiber forming polymers such as polyesters, polyamides, and polyolefins. Examples of the polyolefin include at least one of polypropylene, polyethylene, ethylene copolymer, propylene copolymer, and butene copolymer. Examples of useful polypropylenes include polypropylene available under the trade name Exxon 3445 from Exxon Chemical Company and polypropylene available under the trade name DX 5A09 from Shell Chemical Company. have. The polyamides that can be used in the practice of the present invention can be any polyamide known to those skilled in the art, including copolymers and mixtures thereof. Specifically useful polyamides commercially available are nylon-6, nylon 6,6, nylon-11 and nylon-12. These polyamides are Emerson Industries (Grilon® & Grilamid® Nylon), Sumter, South Carolina, USA, and Atochem Inc., Glen Rock, NJ, USA. Available from numerous sources, such as the Atochem Inc. Polymers Division (Rilsan® Nylon).

In one embodiment of the invention, the neckable material 12 itself may comprise, for example, one or more spunbonded web layers connected to one or more meltblown webs, bonded carded webs, or other suitable layers of material. It can include a multilayer laminate having. For example, the neckable material 12 may comprise a first spunbonded polypropylene layer having a basis weight of about 3.5 to about 270 g / m ² , a meltble having a basis weight of about 3.5 to about 135 g / m ² . It may be a multilayer material having a new polypropylene layer and a second spunbonded polypropylene layer having a basis weight of about 3.5 to about 270 g / m ² . Alternatively, the neckable material 12 may be, for example, a spunbonded web having a basis weight of about 3.5 to about 340 g / m ² or a meltblown having a basis weight of about 3.5 to about 270 g / m ² . It may be a single layer of the same material as the web.

The neckable material 12 may also be a composite material consisting of a mixture of two or more different fibers or a mixture of fibers and particulates. The mixture adds fibers and / or particulates to the gas stream where the meltblown or spunbond fibers are carried so that intimate entanglement of the meltblown or spunbond fibers and other materials occurs prior to collection of the fibers on the collecting device. It can be made to form a coherent web of randomly dispersed fibers and other materials. Examples of such materials include, but are not limited to wood pulp, staple fibers and particulates, such as hydrocolloid (hydrogel) particulates, often referred to as superabsorbent materials.

If the neckable material 12 is a nonwoven web of fibers, the fibers must form a cohesive web structure that can withstand tension and the resulting necking. The coherent web structure can be formed by bonding or entanglement of the individual fibers inherent in the meltblown process. For materials that do not inherently form a coherent web, methods such as hydraulic entanglement, point bonding, aeration bonding, or needle punching may be used to impart certain integrity. Alternatively or additionally, a binder can be used to achieve the desired binding.

The precursor includes any material that can be applied to the neckable material and then treated to cause drying, polymerization, crosslinking, and the like to form a polymer sheet or layer. Preferably, the precursor, once processed, forms an elastomer. In this regard a wide variety of polymers and / or elastomers, for example polyurethanes, silicone rubbers, poly (isobutylene-isoprene), poly (styrene-butadiene), poly (acrylonitrile-butadiene), polychloroprene, poly Isoprene, polysulfide, poly (ethylene-propylene-diene), chlorosulfonated polyethylene, polysiloxane, poly (fluorinated hydrocarbon), poly (acrylate-butadiene), poly (styrene-ethylene / butylene-styrene) Known in the art. In one aspect of the invention, the elastomeric precursor may, according to the term inherent meaning, comprise a thermoset material that crosslinks upon heating. However, elastomeric precursors are also materials which fall within the broader meaning of thermoset materials, for example further polymerization, by means other than heating, such as UV rays, infrared rays, ultrasonic waves as well as other methods known in the art, Materials that cause crosslinking or curing may also be included.

Latex formulations, including those for thermoplastic elastomers, may also be used in the present invention. In the case of latex formulations, the tie layer is formed only when the emulsion is processed, typically consisting of dripping or evaporating water. In addition, elastomeric precursors, such as latex foam rubbers, which can form open and closed cell elastic foams can also be used in the present invention. By way of example, some polyurethanes release CO ₂ gas upon reaction in which they act to form closed cell foam elastomers.

Typically, precursors are formulated to reduce cost—and to improve the method, so that certain formulations will vary with regard to the application and drying, polymerization, curing and / or crosslinking modes of the precursors. Formulations for calendering poly (styrene-butadiene) and polychloroprene are described in Encyclopedia of Polymer Science and Engineering, vol. 6, pages 636-638 (1986). In addition, numerous suitable elastomeric precursors are commercially available, for example thermoplastics consisting of styrene-isoprene-styrene block copolymers, manufactured by DEXCO (a partnership of Dow Chemical and Exxon). DPX-546.00, a latex formulation; B.F. Acrylic latex HYSTRETCH V-29 available from B.F. Goodrich Co .; LSR 590, a two part crosslinkable material available from Dow Corning; And K. Jay, Seabrook, New Hampshire, United States. And Q-THANE QW24, a polyurethane emulsion made by K.J. Quinn & Co.

Additionally, the elastomeric precursor is a thermoplastic polymer endblock containing styrene-based components such as the general formula AB-A 'where A and A' are each poly (vinyl arene), and B is an elastomeric polymer midblock such as conjugated diene. Or latex with an elastomer prepared from a block copolymer having a lower alkylene polymer). Elastomer precursors can be prepared, for example, from latex formulations comprising (polystyrene / poly (ethylene-butylene) / polystyrene) block copolymers available under the trade name KRATON from Shell Chemical Company.

The tie layer 27 is itself tacky or alternatively a tarnish layer 27 which provides an improved bond between the elastomeric sheet 32 and the tie layer 27 by adding a miscible tackifying resin to the precursor formulation. Can be provided. Regarding tackifying resins and tackified elastomer compositions, attention can be paid to resins and compositions as described in US Pat. No. 4,789,699 to Keiffer et al., The entire contents of which are incorporated herein by reference. Any tackifying resin may be used that is miscible with the precursor, neckable material and capable of withstanding processing conditions (eg, temperature). If blending materials are used, for example polyolefins or extender oils, the tackifying resins must also be miscible with these blending materials. REGALREZ and ARKON P series tackifiers are examples of hydrogenated hydrocarbon resins. ZONATAK 501 is an example of a terpene hydrocarbon. REGALREZ hydrocarbon resins are available from Hercules Incorporated. ARKON P series resins are available from Arakawa Chemical (U.S.A.) Incorporated. Of course, the present invention is not limited to the use of the above-described tackifying resins, and other tackifying resins which are miscible with other components and can withstand processing conditions may also be used.

The elastic sheet that comes into contact with the precursor or tie layer may be made from a variety of elastomeric materials, preferably materials that allow the elastic material to be produced in sheet form. Suitable materials commercially available include poly (styrene / ethylene-butylene / styrene) block copolymers available under the name KRATON G from Shell Chemical Company; Polyurethane elastomer materials such as B.F. Available under the trade name ESTANE from Goodrich & Co .; Polyamide elastomeric materials, such as those available under the trade name PEBAX from Rislan Co .; And polyester elastomeric materials such as E.I. Examples of those available under the trade name HYTREL from DuPont De Nemours & Co. include, but are not limited to these. In addition, the elastic layer may be a multilayer material in which it may comprise two or more individual coherent webs or films. In addition, one of the layers in the elastic sheet or multilayer elastic material may contain a mixture of elastic and inelastic fibers or particulates.

The elastic sheet preferably has a basis weight of less than about 30 g / m ² , for example from about 8.5 to about 25 g / m ² . The low basis weight sheet is useful for economic reasons, in particular for use in disposable products. However, depending on the desired use of the elastic composite, an elastic sheet having a higher basis weight of about 30 to about 340 g / m ² may also be used.

As noted above with respect to the tie layer, a tackifier may likewise be added to the elastic sheet to improve the ability to attach the tie layer to its neckable material. However, when a significant amount of tackifier is used in the elastic sheet, the second neckable material (before the elastic neck bonded laminate is wound on the winding rolls to prevent the adhesive elastic sheet from adhering to the back side of the adjacent material on the roll ( Or additional sheet material, such as necked material depending on the entanglement position. Alternatively, dusting of the elastic sheet can be used to prevent unwanted adhesion from occurring when the elastic neck bonded composite material is wound in roll form.

In a further aspect of the invention, an elastic neck bonded composite is formed when the elastomeric precursor 26 is processed while in contact with both the necked material 13 and the ballistic sheet 32. Referring to FIG. 4, schematically illustrated is an exemplary method of applying an elastomeric precursor 26 to a necked material 13 to form a composite elastic neck bonded material 62. Necked material 13, which may be, for example, a reversibly necked material, is released from feed roll 14 and moves in the direction indicated by the associated arrow as feed roll 14 rotates in the direction of the associated arrow. The elastic sheet 32 is unwound from the second supply roll 34 at the same time. The necked material 13 and elastic sheet 32 pass through the nip 54 of the roll assembly 52. However, before entering the nip 54 of the roll assembly 52, an elastomeric precursor 26 is applied to the necked material 13 by a coating assembly 24, such as a bank of spray heads. The coating assembly may be positioned relative to the nip 54 such that the elastomeric precursor 26 is applied to both the necked material 13 and the elastic sheet 32. The necked material 13, elastic sheet 32 and elastomeric precursor 26 together pass through the S-roll assembly 52 formed by the rolls 58 and 59 with the aid of the guide roll 56. .

S-roll assembly 52 may include a series of heated rolls 58 and 59 that process the elastomeric precursor 26, for example, to dry or polymerize the precursor 26. Treatment of the precursor 26 forms a polymer tie layer directly bonded to the necked material 13 and the elastic sheet 32, the plurality of layers collectively comprising an elastic neck bonded laminate 62. One of ordinary skill in the art may require a longer treatment than some formulations are provided by heated calendar rolls 58 and 59, in which case additional heated rolls, infrared heaters, microwaves, for example It will be appreciated that other conventional inline heating techniques by heaters, heating lamps, ovens, and other heating devices known in the art may be used.

As a further example, a bond roll batch (not shown) may be included in the process after treatment of the elastomeric precursor 26. The bond roll arrangement may comprise smooth calender rolls and smooth anvil rolls or may include, for example, patterned calender rolls, eg pin embossing rolls, arranged with the smooth anvil rolls discussed above. Both the calendar roll and the smooth anvil roll can be heated, and the pressure between these two rolls can be controlled by known means to provide a temperature sufficient to heat the tie layer and / or elastic sheet to create an adhesion. Can be. The necessary temperature and / or pressure applied to attach the respective layers will vary depending on the material selected. Typically, sufficient heat and pressure are applied directly to sufficiently heat one of these materials above its T _g to cause its softening.

Conventional drive means and other conventional apparatuses that can be used with the apparatus of FIG. 4 are known in the art and are not illustrated in the schematic diagram of FIG. 4 for the sake of simplicity. In addition, one of ordinary skill in the art appreciates that certain methods may be varied in many respects without departing from the spirit and scope of the invention. For example, the neckable material and elastic sheet can be formed by known extrusion methods as discussed above without first being stored on feed rolls 14 and 34. In addition, the precursor may be applied to the necked material 13 or the elastic layer 32 alone, since the multiple layers are in physical contact prior to processing the elastomeric precursor.

In a further aspect of the invention, referring to FIG. 5 of the drawings, an exemplary method of manufacturing an elastic neck bonded material comprising a plurality of inelastic neckable materials is schematically illustrated. First and second neckable materials 12A and 12B are released from feed rolls 14A and 14B. The first and second neckable materials 12A and 12B then move in the direction indicated by the arrow associated with it, as the feed rolls 14A and 14B rotate in the direction of the arrow associated therewith. The neckable material may be formed by a nonwoven extrusion method, such as a spunbonding or meltblowing method, so that it can be fed directly into the process line without first being stored on a feed roll. It is noted that for the purposes of the present invention the first and second neckable materials need not be the same or even similar materials. The elastic sheet 32 is simultaneously released from the supply roll 34 and moves in the direction indicated by the arrow associated with it. The elastic sheet 32 is placed side by side between the first and second neckable materials 12A and 12B when the material is fed into the nip 74 of the roll assembly 72.

Before the first and second neckable materials 12A and 12B come into contact with the resilient sheet 32 or enter the nip 74 of the roll assembly 72, each of the neckable materials 12A and 12B is each a respective one. Pass under the coating assemblies 24A and 24B. A stream of precursors 26A and 26B oriented from the bank of the spray head across the width of the neckable materials 12A and 12B covers the face of the neckable materials 12A and 12B facing the elastic sheet 32. . Elastomer precursors 26A and 26B are applied immediately before nip 74, which is the point where the neckable material 12A and 12B and the elastic sheet 32 come into contact with each other. This allows both the neckable materials 12A and 12B and both sides of the elastic sheet 32 to be coated with the elastomeric precursor 26. However, precursor 26 may alternatively be applied by other coating methods.

The neckable material 12A and 12B and the elastic sheet 32 lying side by side are directed to and pass through the drive roll assembly 80. Since the peripheral linear velocity of the roll of the S-roll assembly 90 is adjusted higher than the drive roll 80, the continuous material is tensioned between the roll assemblies 80 and 90. By adjusting the difference in the peripheral linear velocity of the roll, multiple layers of material are stretched and necked to a predetermined amount to form the necked multilayer material 88. If additional necking or multistage necking is desired, additional roll assemblies may be added to the process. However, each component is necked before entering the processing apparatus, and the necked multilayer material 88 may be further necked upon heating. The necked material 12A and 12B and the elastic sheet 32 remain in this continuously tensioned and necked state during the formation of the tie layer.

The multilayered necked material 88 is heated by moving through the heated S-roll assembly 90 to form a tie layer, which is in intimate contact with the elastic sheet and each necked material. In the specific embodiment of FIG. 5, the multilayer material 88 is heated while moving around the heated rolls 92 and 94 forming the stacked S-roll assembly 90 to heat both sides of the fabric. Due to the ability of the neckable materials 12A and 12B to penetrate into the surface upon application of the precursor 26, treatment of the precursor 26 is physically around the fiber at or near the surface of the neckable materials 12A and 12B. Forming a tie layer directly bonds to the material and / or mechanically attaches to form a tie layer attached to the necked material. In addition, the heating provided by the processing apparatus 30 can also sufficiently heat the elastic sheet 32 to reset the thermoplastic elastic sheet 32 to the necked dimensions. If desired, additional heating and / or bonding may be provided by the heated rolls 40 and 42. The elastic neck bonded composite is then wound onto a winding roll 46.

Conventional drive means and other conventional apparatuses that can be used with the apparatus of FIG. 5 are known in the art and have not been illustrated in the schematic diagram of FIG. 5 for simplicity. In addition, one of ordinary skill in the art appreciates that certain methods may be varied in many respects without departing from the spirit and scope of the invention. For example, the precursor can be applied to the neckable layers 12A and 12B by covering both sides of the elastic sheet 32 with the precursor 26. As a further example, it is noted that some elastomeric precursors will react at room temperature given sufficient time, and thus heating of the necked continuous layer with the formulation may be omitted. The layers remain in direct contact by the pressure applied on the rolls while being wound on the feed roll 46 to form an elastic neck bonded laminate while the precursor 26 is cured on the roll 46. Let's go.

In a further aspect of the present invention, referring to FIG. 6, a molten elastomer may be applied onto the elastic tie layer and the necked material to form an elastic neck bonded material. The neckable material 12 is released from the supply roll 14 and moves in the direction indicated by the arrow associated with it. The peripheral linear velocity of the feed roll 14 is selected to be less than the linear velocity of the calendar roll assembly 24, and then the neckable material is tensioned a predetermined amount between the supply roll 14 and the drive roll assembly 24. The neckable material may be heated by the heating device 102 while necking. The precursor 26 is then printed onto the material 13 necked by the roll assembly 24. Just before entering the nip 108 formed by the rolls 112 and 114 of the S-roll assembly 110, the molten elastomer 104 is extruded onto the elastomeric precursor 26 and the necked material 13. For example, about 400 ° F. molten polyurethane can be extruded through the one or more die tips 106 onto the precursor 26 forming the elastic sheet 32. Heating from the molten elastomer 104 serves to process the precursor 26, for example to dry the latex, to form the tie layer 27. The second roll 114 of the S-roll assembly 110 may be quenched to rapidly cool the molten elastomer to form the elastic sheet 32 and elastic neck bonded laminate.

Conventional drive means and other conventional apparatuses that can be used with the apparatus of FIG. 6 are known in the art and are not illustrated in the schematic diagram of FIG. 6 for the sake of simplicity. In addition, as noted above, one of ordinary skill in the art appreciates that certain methods may be varied in many respects without departing from the spirit and scope of the invention. By way of example, the elastomeric precursor may be applied before or during the necking of the neckable material 12 and prior to heating.

Example 1

The spunbond material was pre-necked 52 inches wide from 132 inches wide material, and post cure on the rolls and treatment of the rolls allowed the material to equally relax to 72 inches wide. B.F. Acrylic latex, HYCAR 26804, purchased from Goodrich was diluted to about 35% of the solids weight and the pH was adjusted to about 8.5 with ammonia. Acrylic latex was sprayed onto the necked spunbond material using PAASHE Airbrush Set VL-SET with No. 5 needles and No. 5 heads. Acrylic latex was sprayed through peg boards with 1/4 inch diameter holes in each 1 square inch cell. The spunbond material had a basis weight of 45.08 g / m ² before application of the acrylic latex and a basis weight of 47,55 g / m ² after application of the latex and drying in an oven at 108 ° C. for at least 2 minutes. The spunbond material and the applied acrylic latex are B.F. The elastic thermoplastic polyurethane purchased from Goodrich, placed side by side with the elastic film of ESTANE 58661, was placed in a t-shirt press at 130 ° C. for 20 seconds. The resulting elastic neck bonded composite material had good adhesion and good elasticity between the respective layers.

While the invention has been described in detail with respect to specific embodiments thereof, it will be apparent to one skilled in the art that various changes, modifications, and other changes to the invention can be made without departing from the spirit and scope of the invention. . Therefore, the claims are intended to cover all such alterations, modifications and other variations as covered by the appended claims.

Claims (39)

Applying a polymer precursor to the first neckable material, Neck stretching the neckable material to form a necked material, and then Treating the polymer precursor to form a polymer tie layer adhered to the necked material, and Adhering an elastic sheet to the polymeric tie layer to recover when the neckable material is stretched in the necked direction Method of producing a stretchable composite comprising a. The method of claim 1, wherein the polymer precursor is applied in a discontinuous pattern to the neckable material prior to neck stretching the neckable material. The method of claim 2, wherein the polymer precursor consists of a latex. The method of claim 3, wherein treating the polymer precursor comprises drying the latex. The method of claim 2 wherein said polymer layer consists of a thermoset polymer. The method of claim 5, wherein treating the polymer precursor comprises heating. The method of claim 1 wherein the precursor is an elastomeric precursor and the elastomeric precursor is applied to the neckable material prior to neck stretching the neckable material. 8. The method of claim 7, wherein said elastomeric precursor consists of a latex. The method of claim 8, wherein treating the elastomeric precursor comprises drying the latex. 8. The method of claim 7, wherein said elastomer layer consists of a thermoset polymer. The method of claim 10, wherein treating the elastomeric precursor comprises heating. 12. The method of claim 11, further comprising cooling said necked material in a necked state, wherein a reversibly necked material is formed from said neckable material. 8. The method of claim 7, wherein said elastic layer is formed by applying a molten elastomer onto said elastomeric precursor. 8. The method of claim 7, wherein applying the elastomeric precursor comprises applying about 1 g / m ² to about 50 g / m ² of the elastomeric precursor to the neckable material. 8. The method of claim 7, wherein applying the elastomeric precursor comprises applying less than about 20 g / m ² of the elastomeric precursor to the neckable material. 8. The method of claim 7, wherein after treating the elastomeric precursor, an elastic sheet is brought into contact with and adhered to the elastomeric tie layer. 8. The method of claim 7, wherein the elastic sheet is contacted with the elastomeric precursor prior to the treatment to form an elastomeric tie layer. The method of claim 1, wherein the polymer precursor is applied to the neckable material after neck stretching the neckable material. The method of claim 13, wherein the polymer precursor comprises a latex. The method of claim 14, wherein treating the polymer precursor comprises drying the latex. The method of claim 13, wherein the polymer layer comprises a thermoset polymer. The method of claim 16, wherein treating the polymer precursor comprises heating. The method of claim 1, wherein the polymer precursor comprises an elastomeric precursor, and wherein the elastomeric precursor is applied to the neckable material after neck stretching the neckable material. The method of claim 23, wherein the elastomeric precursor consists of a latex. 25. The method of claim 24, wherein treating the elastomeric precursor comprises drying the latex. The method of claim 23, wherein the elastomeric precursor comprises a thermoset polymer. 27. The method of claim 26, wherein treating the elastomeric precursor comprises heating. 28. The method of claim 27, further comprising cooling the necked material in a necked state, wherein a reversibly necked material is formed from the neckable material. The method of claim 23, wherein the elastic layer is formed by applying a molten elastomer onto the elastomer precursor. 24. The method of claim 23, wherein applying the elastomeric precursor comprises applying about 1 g / m ² to about 50 g / m ² of the elastomeric precursor to the neckable material. The method of claim 23, wherein applying the elastomeric precursor comprises applying less than about 20 g / m ² of the elastomeric precursor to the neckable material. 31. The method of claim 30, wherein the elastomeric precursor is treated and then an elastic sheet is contacted with and adhered to the elastomeric tie layer. 33. The method of claim 30, wherein the elastic sheet is contacted with the elastomeric precursor prior to the treatment to form an elastomeric tie layer. An elastic neck bonded composite prepared by the method of claim 1. Porous necked material, An elastic tie layer in intimate contact with the necked material, the elastic layer being mechanically attached to the necked material by surrounding portions of the porous material, and An elastic sheet bonded to the elastic tie layer Elastic neck bonded material comprising a. 36. The neck bonded composite of claim 35 wherein said porous material is a nonwoven material. 36. The neck bonded composite of claim 35 wherein said elastic layer comprises an elastic thermoset polymer. 36. The neck bonded composite of claim 35 wherein said elastic tie layer is less than about 20 g / m ² . 36. The neck bonded composite of claim 35 wherein said elastic tie layer is between 1 g / m ² and 50 g / m ² .