MXPA98009729A

MXPA98009729A - Laminar composite ventilable structure and absorbent articles that use the mi

Info

Publication number: MXPA98009729A
Application number: MXPA/A/1998/009729A
Authority: MX
Inventors: Liu Carroll Nora; Sung Lim Hyun; Joseph Ostpchenko George; R Vaidya Shailaj
Original assignee: Liu Carroll Nora; Curro John Joseph; Ei Du Pont De Nemours And Company; Lavon Gary Dean; Sung Lim Hyun; Mc Kenna J Michael; Ostapchenko George Joseph; Sparks Richard L; The Procter & Gamble Company; Vaidya Shailaja R
Priority date: 1996-05-29
Filing date: 1998-11-19
Publication date: 1999-09-20

Abstract

A ventilatable composite sheet material, a method for making such a sheet material, and an absorbent article using the sheet material that is provided. The composite sheet material is comprised of a thermoplastic film directly adhered to a fibrous substrate. The thermoplastic film comprises at least 50% by weight of a polymer material of the block group of the copolyether ester, copolyether amides, polyurethanes. The substrate comprises a fibrous network of at least 50% by weight of synthetic polymer polyolefin fibers. The composite sheet exhibits a peel strength of at least 0.1 N / cm, a dynamic fluid transmission less than 0.75 g / m2 when subjected to an impact energy of approximately 2400 Joules / m2, and having a vapor transmission rate wet, according to the desiccant method, at least about 1500 g / m2 / 24 hr. The absorbent article comprises: (a) a topsheet, (b) a backsheet, and (c) an absorbent center positioned between the topsheet and the backsheet, wherein the backsheet comprises the non-porous composite sheet material. , impervious to the moist vapor permeable fluid described above. The composite sheet material is oriented such that the sheet layer of the composite sheet material is oriented towards the absorbent center. The absorbent article may comprise a disposable diaper

Description

LAMINAR COMPOSITE VENTILABLE STRUCTURE AND ABSORBENT ITEMS USING THE SAME Field of the Invention This invention relates to a composite structure substantially impervious to liquid, permeable to wet steam useful in clothing, surgical wipes, sterile blankets, packaging materials, protective covers, construction materials and personal care absorbent articles such as diapers and towels. sanitary More particularly, the invention focuses on a wet vapor permeable film and fibrous substrate that combines to form a composite sheet that is durable, strong and flexible, which acts as a barrier to liquids, bacteria and odors, but also highly permeable to wet steam. The invention is also directed to an absorbent article having a backsheet made of the aforementioned composite sheet of the invention.

REF; 28722 Background of the Invention The sheet materials used in making medical drapes, medical nightgowns and absorbent articles, such as diapers and sanitary napkins, should be comfortable and substantially impervious to liquid. The manufacturing and use requirements for these products often demand that the sheet material also be strong and durable.

Infants and other incontinent individuals who use absorbent articles to receive and contain urine and other exudates from the body. The function of the absorbent articles is to contain the discharged materials and isolate these materials from the body of the user and from the clothing and bedding of the users. Suitable absorbent articles having many different basic designs are known in the art. It is also known that the exterior of the absorbent articles can be covered with a flexible sheet, insensitive to steam and fluid to prevent any absorbed fluid from passing through the article and soiling adjacent articles such as clothes, used clothes on a bed, and the similar ones. These external covers, generally referred to herein as backing sheets, are often constructed of films insensitive to vapor and fluid such as polyethylene.

While plastic films do an admirable job of containing liquids, they are not pleasant to the touch and they do not facilitate the passage of wet steam, which makes garments made of plastic films that are not comfortable and irritating to the skin. Plastic films have been made more acceptable for clothing and personal care applications by creating micropores in films to make ventilated microporous films. In microporous films, moisture is transported through the films by means of small holes or holes in the film. A remarkable compound of the microporous film is made of polytetrafluoroethylene which is bonded to a textile material with an adhesive, as set forth in British Patent Application No. 2,024,100. Microporous films adhesively bonded to textile substrates have been used in a variety of garment products, including absorbent articles, as set forth in PCT Patent Publication Nos. WO 95/16562 and WO 96/39031.

Laminates of a microporous film and a fibrous textile substrate have several disadvantages, including that their manufacture requires a separate step of adhesive bonding after the film is made, and that such films allow some filtration of the fluids when used as the film. backing sheet in an absorbent article. For example, when such laminates of microporous films are used as a backing sheet of a disposable diaper, the backing sheet can allow the transmission of some urine through the pores of the backing sheet when a child wearing the diaper is feel. It is special and frequently that the filtration of the liquid occurs through the laminates of the microporous film when the microporous laminate is exposed to a fluid with a low surface tension, as for example when the urine in a diaper is exposed to reagents inside the diaper same.

When fluids flow through the pores of a microporous film, bacteria, viruses, and other microbes can pass through the film along with the fluids. In the same way, the passage of fluids through laminates made with microporous films, if the fluids are liquid or gaseous, also increase the odors emanating from such laminates. Microbial adsorbents have been added to some microporous films with the intention of capturing the microbes that pass through such films, as set forth in Patent Publication No. WO 96/39031. However, it is difficult to distribute microbial adsorbents throughout a microporous film so that all the microbes that percolate through the holes in the film are adsorbed. In the same way, microbial adsorbents frequently prevent the passage of odors through the pores in a microporous film.

Wet vapor permeable films comprise blocks of polyether copolymers, such as the films set forth in U.S. Patent No. 4,493,870, have an advantage in personal care and medical clothing applications because such films are not porous and therefore are substantially impermeable. to the fluids, but these allow the passage of wet steam. U.S. Patent No. 4,725,481 suggests that such films may be attached to a textile fabric by adhesive bonding or fusion bonding. However, the cost to make such films and then bond the films to the fibrous textile substrates has been greatly related to the microporous film laminates. In addition, wet vapor permeable films are known as the films set forth in U.S. Patent Nos. 4,725,481 and 5,445,874 do not actually adhere to various common nonwoven substrates materials, such as polyolefin-based nonwovens without the application of a separate adhesive. .

PCT Patent Publication No. WO 95/16746 (assigned to E. I. duPont de Nemours & Company (hereinafter "DuPont")) exhibits a composition of a copolymer with poleter block combined with an expensive monopolymer thermoplastic homopolymer in order to make a total film that is less expensive, better heat sealable and better self-adhering and other materials. However, the PCT Patent Publication No. WO 95/16746 does not disclose strong and durable composite sheets of thin films that have been extruded directly onto fibrous substrates, nor does this disclose a method for making such composite sheets.

There is a need for a sheet material that acts as a barrier against fluids, but which is also highly permeable to wet steam. There is also a need for a sheet material that easily transmits the wet vapor, but which significantly impedes the passage of bacteria and odors associated with the fluids. There is a further need for a fluid impermeable, moisture vapor permeable laminate material that is also durable, strong and flexible enough to be used in absorbent articles, and can be produced in a commercial manner, for example without the use of bonding adhesives. the layers of the composite sheet in a separate step. Finally, there is a need for an absorbent article that incorporates back sheet, folds in the leg holes, waist protectors, or other features.

Brief description of the invention The invention provides a wet vapor permeable composite sheet material substantially impervious to liquid comprising a fibrous substrate and a wet vapor permeable thermoplastic sheet layer. The fibrous substrate is comprised of at least 50% by weight of thermoplastic polymer fibers. The wet vapor permeable thermoplastic sheet layer is directly bonded by melting to one side of said fibrous substrate. The composite sheet exhibits a resistance to loss of the outer layer of at least 0.1 N / cm, a dynamic transmission of the fluid of less than about 0.75 g / m2 when subjected to an impact energy of approximately 2400 joules / m2, and a wet steam transmission rate of at least 1500 g / m2 / 24hr.

Preferably the sheet layer of the composite sheet has an average thickness of less than 50 microns is comprised of at least 50% by weight of polymer selected from the group of copolyether ester blocks, copolyether block amides, polyurethanes and combinations thereof. It is further preferred that the sheet layer be melt-bonded to the substrate in the absence of an adhesive between the sheet layer and the substrate. The most preferred composite sheet has a resistance to loss of the outer layer of at least 0.15 N / cm, a film thickness of at least 30 microns, and the rate of wet steam transmission, according to the desiccant method, of at least 2500 g / m2 / 24hr, and a dynamic fluid transmission of at least about 0.5 g / m2 when subjected to an impact energy of approximately 2400 joules / m2. The sheet is also substantially free of micropores such that substantially no liquid passes through the sheet when tested according to the liquid moisture filtration test, and the sheet acts as a sweeping passage for microbes when tested in accordance to ISO 11607 standard for sterile packaging materials. The composite sheet must have a tensile strength in the machine direction and a tensile strength in the transverse direction of at least 1 N / cm, and an elongation in the machine direction and an elongation in the transverse direction of at least 30% According to an alternative embodiment of the invention the laminar layer can be joined between two fibrous substrates. According to another alternative embodiment of the invention, the sheet layer of the composite sheet may comprise a moisture permeable film having multiple layers, each sheet layer being comprised of a composition of different wet vapor permeable thermoplastic polymers. One of the layers of the multiple sheet layer may comprise a substantially hydrophilic sheet layer and one of the thin layers comprises a substantially hydrophobic sheet layer. According to another embodiment of the invention, the composite sheet can also include an additional layer of construction and various constitution of the sheet layer and the fibrous layer, such as, for example, a microporous film.

According to the preferred embodiment of the invention, the laminar layer of the composite sheet comprises at least 50% by weight of a Fraction A consisting essentially of a polymer of the block group of copolyether ester, block of copolieter amides, polyurethanes and combinations of these, at least 5% by weight of a Fraction B consisting essentially of a polymer from the group of homopolymers of an alpha-olefin, copolymers or terpolymers containing an alpha-olefin and one or more other monomers, and a block of copolymers of a vinylarene and a conjugated diene, at least 0.1% by weight of a Fraction C consisting essentially of a compatibilizer of Fractions A and B. Fraction C of the film preferably consists essentially of homopolymers, copolymers and terpolymers with main chains which are compatible with Fraction B, the main chains are grafted with a monomer having a functional group that is compatible with a main chain identical to Fraction B, such main chains are grafted with monomers selected from the acidic and alpha- and beta-ethylenically unsaturated carbon anhydrides, and derivatives thereof.

The invention also provides a method for making the ventilatable composite sheet material described above. The thermoplastic polymer selected from the group of copolyester block esters, copolyester block amides, polyurethanes, and combinations thereof are initially mixed. Then, the mixture is melted and mixed simultaneously, and then the melt is extruded through a die in the form of a thin film. The molten mixture is coated directly on a moving fibrous substrate and then forced to be in intimate contact with the substrate as the substrate passes over a suction inlet under vacuum. The composite sheet is finally collected on a pickup roller.

Finally, the invention provides an absorbent article comprising (a) a topsheet; (b) a backing sheet; and (c) an absorbent center positioned between the topsheet and the backsheet; wherein the backsheet comprises the non-porous composite material substantially fluid impermeable permeable to the wet vapor described above. Preferably, the composite sheet material is oriented such that the sheet layer of the composite sheet material is oriented towards said absorbent center. When the sheet layer of the composite sheet comprises a multiple layer film with a substantially hydrophilic elastomer sheet layer and a substantially hydrophobic elastomer film, the substantially hydrophilic elastomer film is preferably placed between the substantially hydrophobic elastomer film and the fibrous substrate. . Alternatively, the sheet layer may further comprise a third substantially hydrophobic elastomer film placed between the hydrophilic elastomer film and the fibrous substrate. The absorbent article may comprise a disposable diaper.

Brief description of the Drawings The accompanying drawings, which are incorporated and constitute a part of this specification, illustrate the presently preferred embodiments of the invention and together with the description, serve to explain the principles of the invention.

Figure 1 is a cross-sectional view of the structure of the composite sheet of the invention.

Figure 2 is a cross-sectional view of a structure of the sheet according to an alternative embodiment of the invention.

Figure 3 is a schematic representation of a process by means of which the structure of the composite sheet of the invention is made.

Figure 4 is a projected view of a disposable diaper embodiment of the present invention having cut portions removed to reveal the underlying structure, as seen inside the diaper.

Figure 5 is an enlarged projected view of the disposable diaper of the present invention in its flat, non-contracted condition showing various panels or areas of the diaper.

Figure 6 is a projected view of another embodiment of a backsheet of the present invention.

Figure 7 is a simplified illustration of an apparatus used to measure the dynamic transmission of fluid from a sheet material.

Detailed description of the invention The reference will now be made in detail by the current preferred embodiments of the invention, examples of which are illustrated below.

The liquid impermeable composite laminate structure permeable to the wet vapor of the invention is shown in Figure 1. The composite sheet 10 is comprised of a fibrous substrate 14 in which a vapor permeable film substantially liquid impervious 12 adheres directly . Such a composite sheet is sometimes referred to as sheet structures. The moisture-permeable film is substantially free of minute holes or pores, although it still has a relatively large rate of wet steam transmission. As used herein, "minute orifices" means small holes inadvertently formed inside the film during the manufacture or processing of the film, while "pores" means small holes within the film that are conventionally formed within the film in order to make to air porous film, wet steam or liquids. In a preferred embodiment of the invention, the substantially liquid-impermeable, wet-vapor permeable film is a copolymer with a block of polyether such as copolymers comprising blocks of copolyester esters, blocks of copolyether amides, polyurethanes or combinations thereof. The fibrous substrate 14 is preferably comprised of synthetic polymer fibers in a form so that the wet vapor permeable film can be adhered directly. The substrate 14 can be a woven or non-woven structure, but for reasons of cost, nonwoven textile structures are preferred for more applications. In an alternative embodiment of the invention shown in Figure 2, the composite sheet structure may be comprised of a moisture permeable sheet layer 12 with two fibrous substrates 14 and 16, each comprised of synthetic polymer fibers, directly adhered on opposite sides of the laminar layer.

According to another embodiment of the invention, a thin layer of a polymer block selected from a group comprising polyethers, polyamides and polyurethanes or combinations thereof could be used in conjunction with a microporous film to form a structure of the film. Such a structure must overcome several disadvantages associated with microporous films, ie bacteria and liquid filtration and high moisture impact values, without sacrificing the relatively large values of MVTR, frequently > 4,000 g / m / 24hr, obtained with some microporous films. The wet vapor permeable films of the composite sheet of the present invention can be made compatible with polyolefin nonwovens and can also be made compatible with microporous film compositions, such as those of polyolefin composition. The wet vapor permeable sheet layer of the composite sheet of the present invention and a microporous film can be bonded by means of adhesive lamination or potentially by direct extrusion coating. The wet vapor permeable film could be combined with a fibrous substrate in a manner consistent with the present invention. This fibrous substrate and the film substantially impermeable to the wet vapor permeable liquid and the microporous film can be bonded, in a manner consistent with the present invention, with a nonwoven sheet bonded to the first side of the vapor permeable sheet layer, substantially impervious to the liquid and a microporous film laminated to the opposite side of the laminar layer.

Alternatively, the current process by which microporosity is incorporated into microporous films of the polyolefin type, such as Exxon Exxaire (Catalog No. XBF-100W), could be used to impart microporosity to a layer of the moisture permeable film within the composite sheet of the present invention, for example, by incorporating a material such as calcium carbonate into the sheet layer. This could result in a wet vapor-permeable laminar layer comprising essentially the block polymer copolyether esters, copolyether block amides, polyurethanes or combinations thereof, with micropores incorporated within them. This laminar layer could then be formed into a laminar structure with thin layers of a non-porous film permeable to wet steam on one or both sides of the microporous film. Additionally, a fibrous substrate could be attached to such a sheet structure of the film in a manner consistent with the present invention.

A particularly preferred nonwoven material for substrates 14 and 16 is a fibrous nonwoven polyolefin network. Suitable polyolefin materials include polyethylene spunbonded networks, cotton or linen fabrics, films with interlaced yarn, carded webs, networks with accelerated spinning and woven or nonwoven webs comprised of blends of polyolefin fibers or polyolefin fibers and other fibers. The networks of the polyolefin fibers can be made with a variety of desirable properties, including good vapor permeability, flexibility, softness and strength. When the sheet 10 is used in an absorbent article, the substrate 14 and 16 should preferably have a tensile strength of at least 1 N / cm and an elongation of at least 30% in both directions the direction of the machine and the transverse direction . The direction of the machine along the direction within the plane of the sheet, for example, the direction in which the sheet was produced. The transverse direction is the direction within the plane of the sheet that is perpendicular to the direction of the machine. More preferably, the fibrous substrates have a tensile strength of at least 1.5 N / cm and an elongation of at least 50% in both directions of the machine and the transverse direction. Preferably, the fibrous substrate also has a porous structure that improves moisture permeability through the composite sheet and the physical bond between the film and the substrate layers of the composite sheet.

One material of the polyolefin sheet that has been advantageously used for the fibrous layers in the invention is the polypropylene sheet material bonded by TYPAR® spinning. He TYPAR® is a registered trademark of DuPont. Another fibrous sheet material that has been advantageously used in the composite sheet of the invention is a commercially bonded thermally bonded polypropylene nonwoven material available from Fiber eb of Simpsonville, South Carolina, under the trade designation of HEC. Substrates 14 and 16 can alternatively be comprised of networks of other synthetic polymer materials such as polyesters or polyamides, bicomponent fibers made of a polyolefin and one or more polymers, or blends of polyolefin fibers and fibers comprised of other synthetic or other materials natural fibers such as cotton or cellulose fibers.

The sheet layer 12 of the structure of the composite sheet 10 is a vapor permeable film substantially liquid impervious. Preferably the sheet layer is extruded directly onto the fibrous substrate 14 and by means of this it adheres to the substrate 14 without the application of an additional adhesive. The sheet layer 12 comprises a thermoplastic polymer material which can be extruded as a continuous, non-porous film, substantially impervious to liquid, permeable to moist vapor. Preferably the layer 12 is comprised primarily of a block of polyether copolymer, such as a polyether ester copolymer, a polyether amide copolymer, a polyurethane copolymer, or combinations thereof. Preferably the copolymer copolymer ester blocks of the sheet layer 12 are segmented elastomers having soft segments of polyether and hard segments of polyester, as set forth in US Patent No. 4,739,012 (assigned to DuPont). Copolymers with polyether ester blocks are sold by DuPont under the tradename Hytrel®. Hytrel® is a registered trademark of DuPont. Copolymers of copolyether amide available for the laminar layer 12 are copolyamides available under the name of Pebax® by Atochem Inc. of Glen Rock, New Jersey, E. U. A. Pebax® is a registered trademark of Elf Atochem, S.A. de Paris, France. Polyurethanes suitable for use in the sheet layer 12 are thermoplastic urethanes available under the name of Estane® from B. F. Goodrich Company of Cleveland Ohio, E. U. A.

The mixing of the thermoplastic polymer or blends of the polymers comprising the laminar layer of the laminar structure of the invention can be carried out according to the methods and techniques known in the art, for example, by physically mixing by rolling followed by extrusion and mixed in a screw extruder equipped with an initial mixer such as those available from Davis-Standard Corp. (Pawcatuck, Rhode Island USA) or an extruder composed of two screws such as those available from Warner-Pfliederer (Ramsey, New Jersey, USA) and Bersdorf Corporation (Charlotte, North Carolina, USA). Alternatively, the loss in weight or volumetric feeders such as those available from K-Tron America (Pitman, New Jersey, E.U.A.) can be used to control the composition that is fed to the extruders.

The composite sheet 10 is preferably prepared by an extrusion coating process. In the extrusion coating process, an extrusion with first uniform fusing is coated on the fibrous substrate material. The molten polymer and the substrate are placed in intimate contact while the polymer cools and binds with the substrate. Such contact and bonding can be improved by passing the layers through a compression formed between two rollers. Alternatively, the molten polymer can be pulled into contact with the fibrous substrate by passing the coated substrate over a suction inlet such that the vacuum pulls the molten polymer into contact with the substrate while it cools and the polymer binds with the substrate. The bond can also be improved by holding the surface of the substrate that is in contact with the film with the treatment surface, such as corona treatment, as is known in the art and described in the Modern Plastics Encyclopedia Handbook, p. 236 (1994), which is incorporated herein by reference.A preferred means for applying the sheet layer 12 to the substrate 14 is illustrated in Figure 3. As can be seen in Figure 3, the thermoplastic polymer is fed in pellet form, along with any additive, into the inlet 26 of the receiver extruder. of the extruder 24. The polymer is melted and mixed in a screw extruder 20a at a screw speed in the range of 10 to 200 rpm, depending on the dimensions of the extruder and the properties of the polymer, and the molten mixture is discharged from the extruder under pressure through the heated line 28 to a die in the form of a flat film 38. The polymer is discharged at a temperature above the melting temperature of the mixture, and preferably at a temperature in the range of 180 ° to 240 ° C. The extrusion melt polymer 40 is discharged from the die in the form of a flat film 38 overlying the fibrous substrate 14.

Preferably, the substrate passes under the die at a speed that is coordinated with the speed of the extruder in order to obtain a desired film thickness. The coated substrate enters a compression formed between the rollers 34 and 36, such rollers are maintained at a selected temperature to obtain a composite sheet with a resistance to loss of the outer layer and vapor permeability. The temperature of rollers 34 and 36 is within the range of 10 ° to 120 ° C. As will be discussed below, it has been found that the high temperatures in the rolls produce a composite sheet with a high resistance to the loss of the outer layer, while it has been found that low temperatures in the rolls produce composite sheets with a greater permeability to humid steam. Preferably, the roller 34 is a smooth rubber roller with a slightly tacky surface coating while the roller 36 is a metal roller. A textured engraved roll can be used in place of the metal roll by the roll 36 if a composite sheet with a more textured laminar layer (and larger surface area) is desired. By passing the coated substrate through the compression formed between the cooled rolls 34 and 36 the molten polymer is quenched while at the same time compressing the molten polymer 40 in and against the fibrous substrate 14. The compression pressure must be high enough. that the resistance to the loss of the outer layer between the film and the substrate is achieved, but not so high that tiny holes are formed inside the film. The cooled polymer forms the sheet layer 12 of the composite sheet 10, such composite sheet is collected on a pickup roller 44. If a trilaminate product similar to that shown in Figure 2 is desired, an additional substrate material can be placed on the another side of the melt of the extruded polymer 40 while the polymer passes between the rolls 34 and 36.

Alternatively, a vacuum process may be applied in order to compress the melt of the polymer 40 against the substrate material. The vacuum process is similar to conventional extrusion coating except that the vacuum is used to join the two substrates in place of the compression rolls. The film is sucked into the fibrous substrate by applying a vacuum force against the underside of the substrate. The vacuum process optimizes adhesion while also producing products with good flexibility and manageability.

According to another. embodiment of the invention, the sheet layer 12 may be a multiple laminar layer structure permeable to moist vapor, substantially impervious to liquid. Such a film can be co-extruded with layers comprised of at least one or more of the above-described materials of preferred thermoplastic films described herein. Such moisture permeable multi-layer films are set forth in U.S. Patent No. 4,725,481 (assigned by DuPont), which is incorporated herein by reference. Multilayer films are especially useful in the composite sheet of the invention where it is desired for the sheet layer 12 to have different properties on its different sides. For example, a composite sheet could be made with a bi-component sheet layer 12 having one side made of a wet vapor permeable polymer material that either thermally bonded to the fibrous substrate 14 and an opposite side comprised of another wet vapor permeable polymer that is a good to materials in which the composite sheet is applied. It is anticipated that a wet vapor permeable film of three or more co-extruded layers could be used for the sheet layer of the composite sheet of the invention in order to obtain a desired group of physical and aesthetic properties of the sheet.

The composite sheet 10 is especially useful as a component in disposable absorbent articles. As used herein, the term "absorbent article" refers to apparatuses which absorb and contain exudates from the body, and, more specifically, refer to apparatuses which are placed against or in close proximity to the wearer's body to absorb and contain several exudates discharged from the body. Absorbent articles include disposable diapers, incontinence briefs, intimate incontinence garments, incontinence towels, feminine hygiene utensils, training pants, garments that are released when pulled, and the like. The term "disposable" is used herein to describe absorbent articles (e.g., they are intended to be disposed of after a single use and, preferably, to be recycled, composted or otherwise disposed in a manner compatible with the environment). The composite sheet 10 has physical properties that make the sheet especially useful as the external "backing sheet" of a disposable absorbent article, such properties include vapor permeability, its substantial liquid impermeability, and its strength and durability of materials of the composite sheet. The ability of the composite sheet 10 to easily transmit the wet vapor means that the sanitary products incorporating the composite sheet 10 as the backing material of the products are more comfortable for the user. The impermeability of the composite sheet 10 to the fluids allows the sheet to fully contain body fluids even when the sheet is "subjected to a dynamic impact of the type experienced when a baby or other person uses an absorbent article feels very strong. The durability of the composite sheet 10 allows the sheet to remain intact even after it has been stretched, rolled and pulled in the process of manufacturing an absorbent article.

It is believed that at the wet vapor transmission rate ("MVTR") of a composite sheet material used as a backing sheet of an absorbent article is important to reduce the humidity and temperature within the absorbent article, thereby reducing the incidence of heat rash and other skin problems associated with such environmental conditions. For example, in order to reduce the rash that induces moisture and heat buildup within a disposable absorbent article, it has been found that at least a portion of the article backing sheet, and preferably the total backing sheet, should have a wet steam transmission rate of at least 1500 g / m2 / 24hr., as measured by the MVTR measured method of the desiccant in the previous examples. The material of the composite sheet of the present invention is capable of delivering an MVTR, as measured by the desiccant method, of at least about 1500 g / m2 / 24hr, and the composite sheets according to the invention can supply an MVTR greater than 4000 g / m2 / 24 hr.

In the composite sheet of the invention, wet steam transmission was improved because the moisture permeable sheet layer 12 was directly extruded onto the nonwoven substrate 14. This direct extrusion improves moisture transmission for several reasons. First, direct extrusion makes it possible to form the composite sheets with very thin layered layers, often with an average thickness of less than 30 microns. These thin films are highly permeable to wet steam but these are still substantially impervious to liquids. Second, because the sheet layer of the composite sheet 10 is extruded directly onto the substrate 14 without the use of an adhesive, there is no adhesive layer to prevent vapor transmission through the composite sheet. Finally, the sheet layer 12 is extruded onto the substrate 14 and passes through such a compression that the film is processed into the pores and contours of the substrate. This process originates a laminar layer 12 having a substrate on the surface 14 that is highly textured so as to have a large surface area.

A cross section of a sample of the composite sheet material of the present invention, made as described in Example 8, was photographed at a magnification level of 500X using a search electron microscope (SEM). An SEM photomicrograph of a section of the sample that was 484 microns long in the direction of bond between the sheet layer 12 and the substrate 14 was elongated and carefully measured using micrometer calibrators. The interface of the film had a total length of 871 microns, of which 411 microns of the interface were directly adhered to the fibers of the substrate within the substrate. It is believed that the large surface area on both sides of the sheet layer 12 further improves the flow of wet vapor through the composite sheet 10.

The composite sheet of the present invention exhibits the most important property that is substantially impervious to liquids under conditions that are normally associated with the use of absorbent articles and clothing for protection. The liquid impermeability of composite sheet 10 has been characterized according to several tests, which include a liquid filtration test, a dynamic barrier test, and a microbial barrier test.

The liquid filtration test visually demonstrates the substantial liquid impermeability of the composite sheet 10. As described in the previous example, this test determines whether a solution of food dye, isopropyl alcohol and water passes through a laminar material . As can be seen in Examples 8-17 below, the ink in an alcohol solution did not pass through the composite sheet 10 of the present invention. On the other hand, when the same test is performed on a sheet comprised of a microporous sheet laminated to a non-woven substrate, filtration of the ink solution was apparent (Comparative Example 1).

The dynamic fluid impact test demonstrates the ability of the composite sheet 10 to resist transmission of the liquid when used as a backing sheet in an absorbent article. The dynamic fluid impact test described in the examples below was designed to simulate the energy per unit area that a baby imparts to a diaper backsheet when abruptly going from a standing to sitting position. The materials of the sheet suitable for the diaper backsheet should exhibit substantially zero dynamic fluid transmission (eg, 2 less than 1 g / m) when subjected to an impact energy of about 1000 joules / m 2, as this is the case for the composite sheet 14 of the invention. More preferably, the backing sheets of the diapers exhibit a substantially zero dynamic fluid transmission when subjected to an impact energy of 2400 joules / m or greater. As reported in the Examples 8-17 below, these examples of the composite sheet of the invention passed less than 0.4 g / m 2 of water when subjected to a 2 impact energy of approximately 2400 joules / m.

The ability of the composite sheet 10 to act as a barrier to liquids also prevents the passage of more odors, bacteria or other microbes through the sheet. When a microporous film was tested according to a bacteria flow test used for the evaluation of sterile porous packaging materials (ASTM F 1608-95) (Comparative Example 1), the material did not pass this test because passing bacteria were found through the sheet. On the other hand, the composite sheet 10 of the invention, being air impermeable in the air porosity test with duration of one hour (See Gurley Hill data in examples 8,9,12,13,16, and 17), meets the requirements as a microbial barrier for sterile packaging materials, as set forth in ISO Standard 11607, section 4.2.3.3.

The strength and duration of the composite sheet 10 makes this sheet especially suitable for absorbent articles. This strength and durability allows the composite sheet 10 to remain intact even after it is stretched, rolled, compressed and pulled during the process of manufacturing an absorbent article. It is also important that the composite sheet is completely strong and durable to remain intact when stretched, pulled and wetted during the use of an article made using the composite sheet 10 as a backing sheet. The strength and duration of the composite sheet 10 have been characterized in terms of (1) tensile strength, (2) the degree to which the sheet will stretch before the break (known as "elongation"), and (3) ) the amount of force required to lose the outer layer of the wet vapor permeable film of the fibrous substrate of the composite sheet (known as "peel strength").

The tensile strength is determined by measuring the tensile force required to break a sample of the sheet material. The elongation is a measure of the amount that a sample of sheet material will stretch under tension before the sheet breaks. The elongation is the length just before the break expressed as a percentage of the length of the original sample. Preferably, a composite sheet material that has been used as the backsheet in an absorbent article has a tensile strength of at least 1 N / cm and an elongation of at least 30% in both directions of the machine and the transverse direction. More preferably, if the composite sheet of the invention is used as the backing sheet in an absorbent article, it must have a tensile strength of more than 1.5 N / cm and an elongation of at least 50% in both directions of the machine and the transversal. In the composite sheet of the present invention, the tension and elongation properties of the composite sheet are largely dependent on the tensile and elongation properties of the fibrous substrate. A material with the preferred tensile strength and elongation remains intact when wound around rollers at high speeds during the manufacture of absorbent articles.

Elongation also makes the article more comfortable to the users because the articles have to be more comfortable for the body shape of the users because a laminar material with this elongation generally has some elasticity. As can be seen in Examples 8-17 below, the composite sheet 10 of the invention has a tensile strength of approximately 11 N / cm in the machine direction and 2 N / cm in the transverse direction, and an elongation from 59% to 87% in the machine direction and 67% to 108% in the cross direction. The polyether block copolymer film of the invention provides a degree of elasticity to a composite sheet material which makes the sheet especially useful in an absorbent article.

The peel strength is a measure of the force required to remove (remove the top sheet) the moisture permeable film from the fibrous substrate of a composite sheet. When the composite sheet 10 is used as a backsheet in a disposable absorbent article, such as a diaper, it is important that the composite sheet has a peel strength of at least 0.15 N / cm, and more preferably at least 0.20 N / cm. cm, so that the sheet does not peel off during the manufacture of the article or during use. It is especially difficult to achieve peel strength when an adhesive is not used to fix the vapor permeable film to the fibrous substrate. Even more difficult to achieve a good peel strength when the wet vapor permeable film is chemically incompatible with the fibrous substrate, as is the case when a moisture permeable film comprises only a copolymer with a polyether ester block coating a substrate based on polyolefins. "Compatibility" of the thermoplastic materials is a recognized term in the art which generally refers to the degree to which the thermoplastic materials are miscible and / or interact with each other. Similarly, "incompatible" materials, as used herein, mean polymer materials that are substantially immiscible or do not interact with each other. Incompatible materials do not wet others well, or adhere well to others, even when heated.

Applicants have discovered that it is possible to greatly improve the peel strength between a moisture permeable film and a fibrous substrate by optimizing the physical bond between the film and the substrate and / or by making the film and substrate more chemically compatible. As is evident in Examples 8-17 below, the composite sheet of the invention generally has a peel strength from 0.3 N / cm to 0.6 N / cm, and a peel strength as large as a total bond strength greater than 0.75 N / cm, which is a degree of bonding above which the substrate will break before delamination occurs.

It has been found that the physical bonding of the wet vapor permeable film and the fibrous substrate can be greatly improved by selecting the materials and binding conditions that promote the physical bonding of the film with the fibers of the fibrous substrate. It has been especially surprising to discover that a good resistance to peeling between the film and the substrate can be achieved by improving the physical bond between the film and the substrate layers, even when the layers are not chemically compatible and the polymer melt of the permeable film Steam is a poor wetting agent of the fibrous substrate.

It has been found that the use of highly fibrous substrate materials, such as a carded network, improves the physical bond between the film and the substrate layers of the composite sheet 10. It has also been found that the use of a polymer for the layer laminate that is sufficiently fluid in its molten state to intertwine with the fibers of the substrate, but not so fluid to run through the fibrous substrate, also improves the resistance to peel off the composite sheet.

It has also been found that extrusion coating and bonding conditions have a great impact on the peel strength between the wet vapor permeable film and the fibrous substrate of the composite sheet. The specific conditions that have been discovered have a significant impact on the peel strength include the temperature of the melt 40 as it leaves the die 38, the spacing between the die and the compression, the compression pressure, the temperature of the compression rolls 34 and 36, and the thickness of the film that is placed below the substrate. It has been found that a melting temperature of the polymer in the range of 180 ° to 240 ° C promotes the excellent bonding of a polyether ester-based moisture-permeable film with a non-woven polyolefin fibrous substrate. These relatively high polymer melting temperatures are thought to lower the viscosity of the polymer film in compression such that most of the polymer penetrates into the fibrous substrate while the composite sheet passes through compression. By minimizing the spacing between the die and the compression it has also been found that it improves the bond in the composite sheet. It is postulated that the decrease between the spacing between the die and the compression helps to maintain the elevated temperature of the polymer laminar layer while the laminar layer goes into compression in order to improve the physical bond between the film and the substrate layers. in compression for the reasons already discussed above. As can be seen in Examples 18-35, a spacing between the die and the compression of about 9 cm can be used to produce a composite sheet with good peel strength, depending on other processing conditions applied.

The binding conditions in the compression itself must also be controlled in order to improve the physical bond between the moisture permeable film and the fibrous substrate. As can be seen in Examples 25 and 31, when other bonding conditions are maintained, an increase in pressure applied to the pressure improves the peel strength of the composite sheet. Keeping the compression rollers at a temperature higher than room temperature in the range of 40 ° to 110 ° C has also been found to improve the physical bonding between the layers of the composite sheet material. As can be seen in Examples 28, 29 and 30, increasing the temperature of rollers 34 and 36 (Figure 3) improves the peel strength of the composite sheet when other bonding conditions are held constant. Applicants believe that the high temperature of the compression rollers help to keep the vapor permeable laminar layer fully fluid while the substantial pressure applied in the compression will cause the polymer of the film to penetrate more effectively into the empty spaces in the substrate. fibrous and transforms more effectively entangled with the substrate.

The physical attachment of the moisture-permeable sheet layer 12 to the fibrous substrate 14 has been foto improve with the thickness of the film. Applicants believe that these improvements are a result of the improved ability of the film thickener to retain heat during the bonding process which serves to decrease the viscosity of the material of the moisture permeable polymer film entering the compression. As discussed above, it is believed that a lower viscosity and a more fluid film easily penetrates the substrate to entangle with the substrate fibers before it solidifies. However, the film thickener tends to have low rates of wet steam transmission and is also more expensive to produce. Thus, the peel strength that can be acquired by making the laminar layer permeable to moisture 12 thick must be balanced against possible losses in wet steam transmission and the expensive addition of the film thickener. It is believed that at a given film thickness, the use of a fibrous substrate material based on lower weight should also help to increase the peel strength.

The chemical interaction between the moisture permeable laminar layer 12 and the fibrous substrate 14 seems to impact both physical and chemical bonds between the layers of the composite sheet. If the polymers of the sheet layer 12 and the substrate 14 are chemically compatible, the polymer of the sheet layer will wet the polymer of the fibers to a greater degree, which, in fact, improves the physical bond between the layers of the composite sheet . Making the polymers of the moisture permeable laminar layer and the more compatible fibrous substrate also increase the level of chemical attraction between the layers of the composite sheet.

The chemical interaction of the wet vapor permeable film and the fibrous substrate is improved by selecting the materials of the film and the substrate materials that are compatible with one another. Moisture-permeable films of copolymers with preferred polyether blocks are compatible with ester-based fibrous substrates, such as polyester webs, and thus adhere well to polyesters. However, such polyether-based block copolymer films are not chemically compatible with the less expensive and stronger polyolefin networks that are more suitable for use in disposable absorbent articles. It has been unexpectedly discovered that the addition of a relatively small amount of certain thermoplastic polymeric materials to polyether block copolymers can dramatically improve the bond between a copolymer film with polyether block and otherwise incompatible with the substrate, such as a polyolefin-based network, without ly impacting the permeability of the liquid, the ability to transmit wet steam, or the strength and duration of the film. It has been discovered that a thermoplastic polymer can be mixed with a copolymer with polyether block to make it possible to improve the extrudate of the polyether copolymer directly on fibrous substrates not ordinarily compatible with the copolymer with copolyether block and to obtain excellent bond between the film and the substrate layers without the application of an adhesive or an additional bonding agent.

An apparatus suitable for the combination of the polyether polymer (referred to above as "Fraction A") and a thermoplastic (referred to earlier as "Fraction B") which is compatible with the substrate 14, is illustrated in Figure 3. Fraction A and 1 Fraction B are mixed by physically joining beads of Fraction A and Fraction B and then pouring the mixture into the inlet 26 of the extruder 24. The balls are fed into the hot screw extruder 20 from these melt and Then they mix. Fractions A and B are ordinarily not compatible with each other such that Fraction B will not self-distribute well through Fraction A as required for good uniform properties of transmission of the wet vapor of the laminar layer 12 and good uniform adhesion between the layer 12 and the layer of the fibrous substrate 14.

However, it has been found that the addition of a small amount of certain compatibilizers can greatly improve the mixing of Fractions A and B.

Preferably, the compatibilizer is a thermoplastic material that serves to improve the processing and uniformity of the mixture of Fractions A and B. The compatibilizer has a character that makes it simultaneously soluble or reactive with Fraction B and interactive with Fraction A, by means of this, to produce a dispersion of globules of Fraction B which adhere to the matrix Fraction A. The compatibilizer (hereinafter "Fraction C") is chosen according to the nature of Fraction B. Fraction C it must have a backbone that is compatible with, and is preferably identical to, Fraction B and a functional group that is compatible with or interacts with Fraction A. The addition of Fraction C changes the morphology of the composition of the mixture as that Fraction B is uniformly distributed in Fraction A in the form of globules that are chemically and / or physically bound to the Fraction A matrix.

Fraction A consists of at least 50% by weight of a block of copolyether ester, a block of copolyamide, a polyurethane, or combinations thereof. Copolymers with preferred copolyether ester blocks for Fraction a are segmented elastomers having soft polyether segments and hard polyester segments, as set forth in US Patent No. 4,739,012 (assigned to DuPont), such as polyether block copolymers ester sold by DuPont under the name Hytrel®. Suitable copolyether amide copolymers under the name Pebax® from Atochem Inc. of Glen Rock, New Jersey. Polyurethanes suitable for use in Fraction A include thermoplastic urethanes available under the name Estane® from B. F. Goodrich Company of Cleveland Ohio. The amount of Fraction A in the polymer blend will vary depending on the polymer composition of Fraction A, 1 type of polymer comprising Fraction B, the desired level of wet vapor permeability, the desired level of bond between the film and the substrate layers, and the roughness of the desired film. Fraction A is typically present in the laminar layer of the composite sheet structure of the invention in an amount in the range from 50% to 95% by weight, and more preferably from 70% to 85% by weight.

Fraction B is typically present in the laminar layer of the composite sheet structure of the present invention in an amount in the range of 5% to 50% by weight, and more preferably between 15% and 30% by weight. Fraction B is preferably a homopolymer of an alpha olefin, a copolymer or a terpolymer containing an alpha olefin and one or more monomers, or blocks of copolymers of vinylarene and a conjugated diene. Fraction B may also contain a mixture of these mono-co- and terpolymers. The selection of the compounds of Fraction B is dependent on the composition of the fibrous material in the substrate 14. For example, if the substrate material is mainly polyethylene, the composition of Fraction B should contain an amount of sufficient polyethylene to make to the film and the most compatible substrate layers.

When Fraction B is a homopolymer, the homopolymer preferably contains the repeating unit - (R-CH-CH2) - wherein R is hydrogen or an alkali radical having between 1 and 8 carbon atoms. Preferred copolymers according to the invention are low density polyethylene (PE-LD), linear low density polyethylene (PE-LLD), high density polyethylene (HDPE), very low density polyethylene (VLDPE) and polypropylene.

Where Fraction B is a co-or terpolymer, this preferably contains the repeating unit of - (R-CH-CH2) - above, with at least one other monethylenically unsaturated monomer (aliphatic or aromatic), the following of these may be cited by Example medium: vinyl acetate, styrene, and (meta) chiral derivatives. This other monomer may represent up to 35% by weight of the olefinic copolymer, and more preferably from 1% to 10% by weight. Preferred copolymers to be used as Fraction B are copolymers of ethylene and propylene, copolymers of ethylene vinyl acetate, copolymers of ethylene and acrylic derivatives (for example, copolymers of ethylene, carbon monoxide and n-butyl acrylate, commonly known as EnBACO), the copolymers of ethylenically unsaturated carboxylic acid monomers (for example acrylic acid, methacrylic acid, crotonic acid, etc.) or the neutralized metal salts thereof (as found in partially neutralized ethylene / carboxylic acid copolymers which they are commonly referred to in the art as ionomers). Fraction B may also comprise terpolymers based on olefins, methyl acrylate and ethyl acrylate or even blends of straight or low density polyolefins. Where Fraction B is a block copolymer of a vinylarene and a conjugated diene, this may have the ABA general structure where the two terminal polymer blocks A comprise blocks of vinylarene thermoplastic polymers such as polystyrene, such block B is a block of polymer of selectively hydrogenated conjugated dienes such as isoprene or butadiene. The proportion of the thermoplastic end blocks with the block of central elastomeric polymers and the relative molecular weights of each of these blocks is balanced to obtain a rubber having an optimum combination of properties such that it behaves like a vulcanized rubber without requiring the current vulcanization step. Such compounds are commonly referred to as block copolymers S-EB-S and are available from the Shell Chemical Company under the name Kraton®. Kraton® is a registered trademark of Shell Oil Company. Optionally, these block copolymers can be grafted with maleic anhydride as well as chiral forms which contain 0.1% to 10% by weight, preferably 0.2% to 5% maleic anhydride (see US Patent 4, 578, 429).

The compatibilizer of Fraction C is typically in the laminar layer of the composite sheet structure of the invention in an amount in the range from 0.1% to 15% by weight, and more preferably between 1% and 8% by weight. Preferred linear chains for Fraction C include low density polyethylene (PE-LD), linear low density polyethylene (PE-LLD), high density polyethylene (HDPE), very low density polyethylene (VLDPE) and polypropylene. The reactive group of Fraction C may be a grafted monomer that is grafted to a backbone, and this is or contains at least one alpha- or beta-ethylenically unsaturated carbonic acid or anhydride, or derivatives thereof.

Examples of such carboxylic acids and anhydrides, which may be mono-, di- or polycarboxylic, are acrylic acids, methacrylic acid, maleic acid, fumaric acid, itaconic hydrate, maleic anhydride and maleic anhydride substitutes (e.g., dimethylmaleic anhydride) . Examples of unsaturated acid derivatives are salts, amides, imines and esters (for example, mono- and disodium maleate, acrylamide, maleimide and diethyl fumarate). Maleic anhydride is a preferred grafted monomer for the reactive group of Fraction C. The grafting of the polymers can be carried out in the molten state, in solution or in suspension. The viscosity of the molten grafted polymer is not restricted, however, the highest permissible effectiveness is found if the melting point, measured at 2.16 kg and 190 ° C, is between 1 and 15 g / 10 min. Such grafted polymers can be prepared as is known in the art.

In addition to the above fractions, the laminar layer in the laminar structures according to the invention may contain conventional additives, such as pigments and fillers (eg, Ti02, calcium carbonate, silicas, clays, talc) and stabilizers, such as anti-oxidants. and ultraviolet light absorbers. These additives are used for a variety of purposes, including reducing the cost of the laminar layer of the composite sheet structure, and altering the morphology of the laminar layer of the laminar structure. However, such additives have been discovered to reduce the transmission of wet vapor through the laminar structure. It is important to maintain the amount of additive in the film at a level that does not cause the transmission speed of the wet vapor of the sheet to fall outside the range required for a particular application. The sheet layer may be comprised between 0.01% and 30% additive material, and more preferably between 0.5% and 7% of an inert filler material.

A preferred embodiment of an absorbent article incorporating the composite sheet of the present invention is diaper 50, shown in Figure 4. As used herein, the term "diaper" refers to an absorbent article generally worn by infants and incontinent persons that are used approximately below the user's torso. Figure 4 is a projected view of the diaper 50 of the present invention in its state without contractions, flat (e.g., with elastics that induce contraction upon detachment) with portions of the structure being cut to clearly show the construction of the diaper 50 As shown in Figure 4, the diaper 50 preferably comprises a containment assembly 70 comprising a top sheet 49; a backing sheet 47 attached to the topsheet; and an absorbent center 75 positioned between the topsheet 49 and the backsheet 47. The absorbent center 75 has a pair of opposed longitudinal ends, an inner surface and an outer surface. The diaper preferably further comprises elastic fractions of the legs 72; elastic fractions of the waist 74; and the fixing system 76 preferably comprises a pair of securing members 77 and a trapping member 78.

The diaper 50 is shown in Figure 4 with the portion of the diaper 50 with surfaces, the interior surfaces 73, the viewing surface. The diaper 50 shown in Figure 4 has an internal surface 73 (the surface of 'seen in Figure 4), an outer surface 71 opposite the inner surface 73, a back or backrest region 45, a front region of the waist 46 opposite the backside region 45, a region of the crotch 48 placed between the region of the rear 45 and the rear front region 46, and a perimeter which is defined by the outer perimeter or ends of the diaper 46 in which the longitudinal or lateral ends are designated 50 and the ends endings are designated 52. The inner surface 73 of the diaper 50 comprises the portion of the diaper 50 which is positioned adjacent to the wearer's body during use (eg, the inner surface 73 is generally formed by at least a portion of the top sheet 49 and other components attached to the topsheet 49). The outer surface 71 comprises the portion of the diaper 50 which is positioned away from the wearer's body (for example, the outer surface 71 is generally formed by at least a portion of the backing sheet 47 and other components attached to the backing sheet 47). As used herein, the term "attached" encompasses the configurations by means of which one element is directly secured to the other element by fixing the element directly to the other element, and the configurations by means of these the element is indirectly secured to the other element. when fixing the element to the intermediate member (s) in which it is in fact fixed to the other element. The back region of the waist 45 and the front region of the waist 46 extended from the end ends 52 of the periphery to the crotch region 48.

The diaper 50 also has two centerlines, a longitudinal center line 100 and a transverse center line 110. The term "longitudinal", as used herein, refers to a line, axis, or direction in the plane of the diaper 50 that is generally aligned with (e.g., approximately parallel to) a vertical plane which bisects a user seated in the left and right half when the diaper 50 is used. The terms "transverse" and "lateral", used herein, are interchangeable and refer to a line, axis or direction which remain within the plane of the diaper which is generally perpendicular to the longitudinal direction (which divides the product into front and rear body halves).

Figure 5 shows a simplified projected view of the diaper 50 of Figure 4 depicts several panels and their positions relative to one another. The term "panel" is used herein to denote an area or element of the diaper. (While a panel is typically an area or distinctive element, a panel can match (correspond functionally) something with an adjacent panel). The diaper 50 has a crotch region 48 comprising a main panel 80 and a pair of leg panels 82; a front region of the waist 46 comprising a central panel comprising a middle panel 86 and a panel of the waist band 88, and side panels 90; and a rear region of the waist 45 comprising a central panel comprising a middle panel 86 'and a panel of the waist band 88', and side panels 90 '. The main panel 80 is the portion of the diaper 50 from which the other panels emanate. The absorbent center is generally positioned within the main panel 80 since the exudates are typically discharged in this region of the diaper although the absorbent center will probably also extend within the middle panels 86 and 86 '. A leg panel 82 generally extends longitudinally outward from and along each end 81 of main panel 80. Each leg panel 82 generally forms at least a portion of the elastic fractions of the leg. In the front region of the waist 46, the middle panel 86 of the central panel extends laterally outwardly from and along the lateral end 85 of the main panel 80. The waist band panel 88 generally extends longitudinally outwardly. of the middle panel 86. the side panels 90 each generally extending outwardly from and along the center panel. In the back region of the waist 44, the middle panel 86 'of the central panel generally extends longitudinally outwardly from and along the lateral end 85 of the main panel 80. The waistband panel 88' generally extends longitudinally outwardly from and along the panel 86 ' The side panels 90 'of each generally extend laterally outwardly and along the central panel.

Referring again to Figure 4, the assembly of the container 70 of the diaper 50 is shown as comprising the main body (frame) of the diaper 50. The assembly of the container 70 preferably comprises a topsheet 49, a backsheet 47 and a center absorbent 75 having a pair of longitudinal opposite ends, an inner surface, an outer surface. The inner surface of the absorbent center is generally oriented towards the user's body while the outer surface is oriented away from the user's body. When the absorbent article comprises a fastener and a liner, (e.g., assembly of the container 70 comprises one or more layers of material to define the fastener while the liner comprises an absorbent composition such as the topsheet, a backing sheet, and an absorbent center). For the unitary absorbent articles, the container 70 assembly preferably comprises the topsheet 49, the backsheet 47 and the absorbent center 75 of the diaper with other features added to form the composite structure of the diaper.

Figure 4 shows a preferred embodiment of the containment assembly 70 in which the topsheet 49 and the backsheet 47 have generally length and width dimensions greater than those of the absorbent center 75. The topsheet 49 and the backsheet 47 extends beyond the ends of the absorbent center 75 thereby forming the periphery of the diaper 50. While the topsheet 49, the backsheet 47, and the absorbent center 75 may be assembled in a variety of well-known configurations In the art, exemplary containment mounting configurations are generally described in US Pat. No. 3,860,003 entitled "Contractible Side Portions for Disposable Diaper" which was published by Kenneth B. Buell on January 14, 1975; U.S. Patent No. 5,151,092 entitled "Absorbent Article With Dynamic Elastic Waist Feature Having A Predisposed Resilient Flexural Hinge" which was published by Kenneth B. Buell et al., On September 29, 1992; and U.S. Patent No. 5, 385,500 entitled "Absorbent Articles Providing Sustained Dynamic Fit" which was published by LaVon et al., on October 25, 1994, each of which is incorporated herein by reference.

In the embodiment shown in Figure 4, the backsheet 47 preferably comprises a continuous sheet or layer in which the front region of the waist 46, the back region of the waist 45, and the region of between the leg 48 are defined. As used herein, the term "layer" does not necessarily limit the element to a single layer of material where a layer can currently comprise laminations or combinations of network sheets of required types of materials. The backing sheet 47 has an inner surface and an opposite outer surface. The internal surface is that proportion of the backing sheet 47 which is positioned adjacent to the absorbent center. The outer surface of the backsheet 47 corresponds to the outer surface 71 of the diaper 50. Since the backsheet 47 preferably defines the front region of the waist 46, and back of the waist 45, and the region of the between the leg 48, the backing sheet 47 also has corresponding regions and panels as previously defined. (For simplicity, these regions and panels are denoted in the drawings by the same numerical reference so that the same diaper regions and panels correspond as shown in Figure 5).

In the modality shown in Figure 4, the The absorbent center is placed in the main panel 80, since the exudates are typically discharged in this region and extend within the middle panels 86, 86 '. In the embodiment shown in Figure 4, the absorbent center does not extend within the leg panels 82, the waistband panels 88 and 88 ', or the side panels 90 and 90'. In other embodiments, the absorbent center may extend within all or some of the leg panels 82, the waistband panels 88 and 88 'and the side panels 90 and 90'.

The backsheet 47 of the present invention is that portion of the diaper 50 which is generally positioned away from the wearer's skin and which prevents the exudates absorbed and contained in the absorbent center 75 from the wetting articles that are in contact with it. the diaper 50 such as sheets and underwear. Thus, the backing sheet 47 is substantially insensitive to fluids (eg, urine). In addition to being insensitive to fluids, backing sheet 47 is also permeable to wet steam. For disposable diapers, it has been discovered that wet vapor permeability is critical for the special development in hot and humid conditions. When an absorbent article is placed on a wearer, the skin is covered by the materials that make up the absorbent article. This concealment of the skin, especially in hot and humid conditions, prevents evaporation and causes cooling of the covered area. The resulting perspiration increases the relative humidity of the air within the absorbent article and less user comfort negative benefits perceived by the articles that provide absorbent protection. In order to reduce moisture and heat build-up within the disposable honeycomb, it has been found that at least a portion of the backing sheet 47, and more preferably the entire backing sheet 47, must have a wet steam transmission rate. of at least 1500 g / m2 / 24 hr., and preferably at least 2500 g / m / 24 hr. , and even more preferably at least about 4000 g / m2 / 24 hr. As discussed above, the composite sheet 10 of the present invention has an ideal wet vapor transmission rate for use as a backsheet in a disposable absorbent article, such as the disposable diaper 50 of Figure 4. For such application , the composite sheet 10 is used with the laminar layer 12 that forms the inner portion that faces the center of the backing sheet and the substrate 14 that forms the garment-facing portion of the backing sheet.

The backsheet 47 comprised of the backsheet 10 is preferably placed adjacent to the outer surface of the absorbent center 75 and is preferably attached thereto by any suitable joining means known in the art for attaching such materials. For example, the backsheet 47 can be secured to the absorbent center 75 by a continuous uniform layer of adhesive, a molded layer of adhesive, or an array of lines, spirals, or separate spots of adhesive. An example of a suitable joining means comprises an open molded network of adhesive filaments is disclosed in US Patent No. 4,573,986 entitled "Disposable Waste-Containment Garment", which was published by Minetola et. in March 4, 1986. Other suitable bonding means comprise several spiral filament filament lines within a spiral pattern illustrated by the apparatus and method shown in US Patent No. 3,911,173 published by Sprague, Jr. on October 7, 1975; US Patent No. 4,785,996 published by Ziecker, et al, on November 22, 1978; and U.S. Patent No. 4,842,666 published by Werenicz on June 27, 1989. Each of these patents is incorporated herein by reference. Alternatively, the joining means may comprise hot junctions, pressure joints, ultrasonic joints, dynamic mechanical joints, and any other suitable joining means or combinations of these joining means as are known in the art.

In terms of the methods of joining the sheet material or other compounds of an absorbent article, and more particularly to joining the wet vapor-permeable sheet layer, impervious to the liquid of the composite sheet to other components, it has been observed that only certain methods of union will form unions of sufficient strength so that forces active agents found in normal use particularly after the sheet layer has been subjected to fluid contact and has absorbed the fluid. Without wishing that this bond is presently believed in theory that the sheet layers of interest in accordance with the present invention provide the desired superior development properties in terms of moisture vapor transmission due to their high comparative moisture contents under conditions in use. Comparatively this great moisture content, however, it is believed that currently it has negative implications on the bond strength of the bond between certain conventional hot melt adhesives and the sheet layer.

One method in which he has successfully tested is the use of a polyurethane-based adhesive in accordance with the conventional application techniques of the adhesive and equipment generally known in the art, as described above. Another method, which is currently preferred, is the use of multi-layer, co-extruded sheet layers described above with reference to the aforementioned and incorporated in U.S. Patent No. 4,725,481 by Ostapchenko. By using this multiple sheet layer method, the multiple sheet layer structure (in a bi-layer extrusion) is extruded onto the fibrous substrate material with the comparatively more hydrophobic elastomer layer facing outward from the substrate and the elastomer layer comparatively more hydrophilic oriented towards the substrate. Typically, for a given thickness of the hydrophobic elastomer layer it exhibits a lower MVTR development than the hydrophilic elastomer layer due to its comparatively low moisture contents under conditions of use. However, when employed in a comparatively thin layer, the effect of the hydrophobic sheet layer with low moisture content does not significantly decrease the MVTR development of the total composite sheet. Due to the low moisture content of the hydrophobic elastomeric layer, bonding techniques and conventional hot melt adhesives can be used to form bonds of adequate strength between the composite sheet and other components of the absorbent article even when the film has been wetted. Accordingly, by using a coextruded, multi-layered, co-extruded laminar layer a composite sheet can be provided which exhibits both desired development properties for the composite sheet of the present invention and can be attached to other components of absorbent articles by means of union with conventional adhesives. (See Examples 36-39 below).

Totally and unexpectedly, additional development benefits have been discovered through the use of multi-layer films used in the construction of absorbent articles such as diaper 50. More particularly, the use of a multiple layer film comprises a three layer structure with a layer The hydrophobic elastomer surrounded on both surfaces by a hydrophilic elastomer layer is believed to provide better tactile qualities when extruded onto the fibrous substrate to form a composite sheet. Again without wishing to be theoretically related, it is believed that the comparatively low moisture content of the hydrophobic sheet layers cause a drier tactile impression when the fibrous substrate layer is comparatively thin. As a multiple layer (tri-layer) embodiment of a composite sheet material would therefore provide improved bonds with adhesive techniques and improved tactile printing of the sides of the fibrous substrate layer. Optionally, as discussed, truly dual side configurations could be constructed analogously to Figure 2 where the multi-layer / tri-layer sheet structure is oriented on both sides of the substrate layer. Optionally, as discussed above, truly lateral dual configurations could be constructed analogously to Figure 2 where the multi-layer / tri-layer sheet structure is oriented on both sides of the fibrous substrate material to provide improved tactile printing on both sides. As an embodiment it is believed to be particularly desirable for such applications as leg cuffs, waistbands, side panels, and other aspects for absorbent articles such as diapers where a wearer may be in contact with both surfaces of the composite sheet material.

Also contemplated are embodiments of the present invention from the absorbent center not attached to the backsheet 47, and / or to the topsheet 49 in order to provide greater extensibility in the front region of the waist 46 and the back region of the waist Four. Five.

The absorbent center 75 may be any absorbent member which is generally compressible, conformable, non-irritating to the wearer's skin, and capable of absorbing and retaining fluids such as urine and other exudates from the body. As shown in Figure 4, the absorbent center 75 has one side facing the garment, one side facing the body, a pair of side ends, and a pair of ends at the waist. The absorbent center 75 can be manufactured in a wide variety of sizes and shapes (eg, rectangular, hourglass, T-shape, asymmetric, etc.) and from a wide variety of fluid-absorbing materials commonly used in disposable diapers and others. absorbent articles such as mixed wool pulp generally referred to as aerated felt. Examples of other suitable absorbent materials include bundles of twisted cellulose; molten polymers that include two forms; chemically rigid, cross-linked or modified cellulosic fibers; fabrics that include woven fabrics and woven laminates; absorbent foams; absorbent sponges; superabsorbent polymers; absorbent gelatinizing materials; or any equivalent material or combinations of materials.

The configuration and construction of absorbent center 75 may vary (e.g., the absorbent center may have micrometric gauge road zones, a hydrophilic gradient, a superabsorbent gradient, or low average density, and acquisition zones on a low average weight basis; or may comprise one or more structures). In addition, the size and absorbent capacity of the absorbent center 75 can be varied to suit the users ranging from children to adults. However, the total absorbent capacity of the absorbent center 75 must be compatible with the designed load and the intended user of the diaper 50.

A type of diaper. 50 has an asymmetric absorbent center, T-shaped 75 having ears in the front region of the waist but a rectangular shape in the rear region of the waist. Exemplary absorbent structures for use as an absorbent center 75 of the present invention which has achieved wide acceptance and commercial access are described in US Patent No. 4,610,678 entitled "Higt-Density Absorbent Structures" published by Weisman et al. on September 9, 1986; U.S. Patent No. 4,673,402 entitled "Absorbent Articles With Dual-Layered Cores" published by Weisman et al. on June 16, 1987; U.S. Patent No. 4,888,231 entitled "Absorbent Core Having A Dusting Layer" published by Angstadt on December 19, 1989; and U.S. Patent No. 4834,735, entitled "High Density Absorbing Members Having Loose Density and Lower Basis Weigth Acquisition Zones", published by Alemany et al. in May 30, 1989. The absorbent center may further comprise the dual center system containing an acquisition / distribution center of chemically rigid fibers positioned over an absorbent storage center as detailed in US Patent No. 5,234,423, entitled "Absorbent Article. With Elastic Waist Feature and Enhaced Absorbency "published by Alemany et al., On August 10, 1993; and in U.S. Patent No. 5,147,345, entitled "High Efficiency Absorbent Articles for Incontinence Management", published by Young, LaVon and Taylor on September 15, 1992. All of these patents are incorporated herein by reference.

The topsheet 49 is preferably positioned adjacent to the inner surface of the absorbent center 75 and is preferably attached to it and the backsheet 47 by attachment means (not shown) such as those described above with respect to bonding. the backsheet 49 to the absorbent center 47. In a preferred embodiment of the present invention, the topsheet 49, and the backsheet 47 are bonded directly to each other at the periphery of the diaper and directly attached together directly attached to the diaper. Absorbent center 75 by any suitable means.

The topsheet 49 is preferably docile, of soft feel and non-irritating to the wearer's skin. In addition, the topsheet 49 is preferably sensitive to fluids (eg, urine) allowing it to easily penetrate through its thickness. A topsheet 49 can be manufactured from a wide range of materials such as nonwoven woven materials; polymeric materials such as an open formed thermoplastic film, open plastic films, and hydroformed thermoplastic films; porous foams; cross-linked foams; crosslinked thermoplastic films; and cotton fabrics. Suitable woven and nonwoven materials may comprise natural fibers (e.g., wood or cotton fibers), synthetic fibers (e.g., polymeric fibers such as polyester, polypropylene or polyethylene fibers) or a combination of natural and synthetic fibers. The topsheet 49 is preferably made of hydrophobic material to isolate the wearer's skin from the fluids which have passed through the topsheet 49 and are contained in the absorbent center 75 (eg, to prevent it from getting wet again). If the topsheet 49 is made of a hydrophobic material, at least the uppermost surface of the topsheet 49 is treated to be hydrophilic so that the fluids are transferred through the topsheet more rapidly. This decreases the likelihood that the body exudates will flow out of the topsheet 49 instead of exiting through the topsheet 49 and being absorbed by the absorbent center 75. The topsheet 49 may be hydrophilically represented by treating this with a reagent Suitable methods for treating the topsheet 49 with a reagent include spraying the material of the topsheet 49 with the reagent and immersing the material in the reagent. A more detailed discussion of such treatment and hydrophilicity is contained in U.S. Patent No. 4,988,344 entitled "Absorbent Articles with Multiple Layer Absorbent Layers" published by Reising, et al on January 29, 1991 and U.S. Patent No. 4,988,345 entitled "Absorbents with Rapids Acquiring Absorbents Cores "published by Reising on January 29, 1991, each of which is incorporated herein by reference. As mentioned in the foregoing background, each hydrophilic material tends to reduce the surface tension of the bodily fluids discharged from the absorbent article, which increases the likelihood of leakage of the liquid there are pores or tiny holes in the backing sheet of the article. .

A preferred alternative of the topsheet comprise grooved films are preferred for the topsheet because these are sensitive to body exudates and yet non-absorbent and have a reduced tendency to allow fluids to return and wet the wearer's skin again. Thus, the surface of the formed film which is in contact with the body remains dry, thereby reducing the soiling of the body and creating a more comfortable feeling for the user. Suitable formed films are described in U.S. Patent No. 3,929,135, entitled "Absorptive Structures Having Tapered Capillaries", which was published by Thompson on December 30, 1975; U.S. Patent No. 4,324,246 entitled "Disposable Absorbent Article Having A Stain Resistant Topsheet", which was published by Mullane, et al. on April 13, 1982; U.S. Patent No. 4,342,314 entitled "Resilient Plástic Web Exhibiting Fiber-Lke Properties", which was published by Randel et al., on August 3, 1982; U.S. Patent No. 4,463,045 entitled "Macroscopically Expanded Three-Dimensional Plastics Web Ex ibinting Non-Glossy Visible Surface and Cloth-Like Tactile Impression", which was published by Ahr et al. on July 31, 1984; and U.S. Patent No. 5,006,394"Multilayer Polymeric Film" published by Baird on April 9, 1991. Each of the patents is incorporated herein by reference.

It may be desirable to provide the disposable absorbent article of the present invention with extensibility or resiliency in all or a proportion of the side panels 90. (As used herein, the term "extensible" refers to materials that are capable of extending at least in one direction to a certain degree without undue rupture The terms "elasticity" and "elastically extensible" refer to extensible materials that have the ability to return to their original dimensions approximately after the force that has spread the material has been removed. As used herein, any material or element described as "extensible" may also be elastically extensible unless otherwise provided). Extendable side panels 90 provide a more comfortable contour shape by making the diaper fit to the wearer and holding this fit throughout the time of use that happens when the diaper has been loaded with exudates since the side panels allow the sides of the diaper expand and contract. The extendable side panels 90 further provide greater effectiveness of application of the diaper 50 since even if the wearer of the diaper pulls a side panel 90 further than others during the application (asymmetrically), the diaper 50 will "self-adjust" during use. While the extendable side panels 90 can be constructed in various configurations, examples of diapers with extendable side panels are disclosed in US Patent No. 4,857,067, entitled "Disposable Diaper Having Shirred Ears" published by Wood, et al. on August 15, 1989; U.S. Patent No. 4,381,781 published by Sciaraffa, et al., July 3, 1990; and U.S. Patent No. 5,151,092 published by Buell et al. on September 29, 1992; each of which are incorporated here as a reference.

Extendable side panels or any other elements of the diaper 50 in which extensibility or elasticity such as belt bands are desirable may comprise materials that have been "pre-stretched" or "mechanically pre-stretched" (eg, subject to some degree of mechanical stretching of localized pattern to permanently lengthen the material), or networks as elastic structures, as described in US Pat. No. 5,518,801 published by Chappell et al. on May 21, 1996. The materials may be pre-stretched using deep etching techniques as is known in the art. Alternatively, the materials may be pre-stretched by directing the material through the incremental mechanical stretching system as described in U.S. Patent No. 5,330,458 published by Buell et al., On July 19, 1994. The materials are then allowed to return to its conditions substantially without tension, thus, forming a stretched material with zero stretch that is extensible, at least up to the point of initial stretch. Examples of zero stretch materials are disclosed in US Patent No. 2,075,189 published by Galligan on March 30, 1937; U.S. Patent No. 3,025,199 published by Harwood on March 13, 1962; U.S. Patents Nos. 4,107,364 and 4,209,563 published by Sisson on August 15, 1978 and June 24, 1980, respectively; U.S. Patent No. 4,834,741 published by Sabee on May 30, 1989; and U.S. Patent No. 5,151,092 published by Bull et al., on September 29, 1992. All of the patents referred to above are incorporated by reference.

The diaper 50 preferably further comprises fractions of the elastic legs 72 to provide improved containment of fluids and other exudates from the body. Each fraction of the elastic leg 72 may comprise several different embodiments to reduce the leakage of body exudates in the leg combs 82 (the fraction of the elastic leg may be and is sometimes also referred to as leg bands)., lateral wings, barrier folds, or elastic folds). U.S. Patent No. 3,860,003 discloses a disposable diaper which provides an opening in the contractible leg having a latral wing and one or more elastic members to provide a double in the collapsible leg (joint doubles). U.S. Patent No. 4,909,803 entitled "Disposable Absorbent Article Having Elastized Flaps" published by Aziz et al., On March 20, 1990, describes a disposable diaper having "resilient" elastic wings (folds as a barrier) to improve the containment of the regions of the legs. U.S. Patent No. 4,695,278 entitled "Absorbent Article Having Dual Cuffs" published by Lawson on September 22, 1987; and U.S. Patent No. 4,795,454 entitled "Absorbent Article Having Leakage-Resistant Dual Cuffs" published by Dragoo on January 3, 1989, discloses disposable diapers having double folds that include a tie doubles and a barrier doubles. U.S. Patent No. 4,704,115 entitled "Disposable Waist Containment Garment" published by Buell on November 3, 1987, discloses a disposable diaper or incontinence garments having safety channels for leakage at the ends configured to contain free fluids within the article of clothing. Each of these patents are incorporated herein by reference.

While each fraction of the elastic leg 72 can be configured so as to be similar to any of the leg bands, side wings, barrier folds or elastic folds described above, it is preferred that each fraction of the elastic leg 72 comprises at least an internal barrier fold comprising a wing as a barrier and a spacing element as described in U.S. Patent No. 4,909,803 referred to above. In a preferred embodiment, the fraction of the additional elastic leg 72 comprises an elastic binder fold 63 with one or more elastic threads 65, placed outside the barrier fold as described in US Patent No. 4,695,278 referred to above.

The diaper 50 further preferably comprises an elastic fraction of the waist 74 that provides better fit and containment. The elastic fraction of the waist 74 is that portion or area of the diaper 50 which is elastically expanded and contracted for a dynamic adjustment to the wearer's waist. The elastic fraction of the waist 74 preferably extends longitudinally outwardly from at least a portion of the waist ends of the absorbent center 75 and generally at least a portion is formed at the trailing end of the diaper 50. Diapers are generally constructed in order to that they have two elastic bands of the waist, one placed in the rear region of the waist and one placed in the front region of the waist, although the diapers can be constructed with an elastic band for the waist. In addition, while the elastic fraction of the waist 74 or any of its constituent elements may comprise a separate element fixed to the diaper 50, the elastic fraction of the waist 74 may be constructed as an extension of other diaper elements such as the backing sheet. 47 or the upper sheet 49, preferably both backing sheets 47 and the upper sheet 49. Modalities are also contemplated where the elastic fraction of the waist 74 comprises openings, as described above, to provide it to be ventilatable in the waist regions. . The elastic fractions of the waist 74 may be constructed in several different configurations including those described in US Pat. No. 4,515,595 entitled "Disposable Diapers with Elastically Contractible Waistbands" published by Kievit et al., May 7, 1985 and the Patent. North American No. 5,151,092 published by Buell referred to above; each of which is incorporated herein by reference.

The diaper 50 also comprises a fastening system 76 which forms a closed side which maintains the back region 45 the front region of the waist 46 in a lapped configuration such that the lateral tensions are maintained around the circumference of the diaper to maintain the diaper in the user. Exemplary fastening systems are disclosed in Patent No. 3,848,549 published by Buell on November 19, 1974; U.S. Patent No. 4,662,875 published by Hirotsu and Robertson on May 5, 1987; U.S. Patent No. 4,869,724 published by Scripps on September 26, 1989; U.S. Patent No. 4,846,815 published by Scripps on July 11, 1989; U.S. Patent No. 4,894,060 published by Nestegard on January 16, 1990; U.S. Patent No. 4,946,527 published by Battrell on August 7, 1990; and U.S. Patent No. 5,326,612 entitled "Nonwoven Female Component for Refastenable Fastening Device and Method of Making the Same" published by David J. K. Goulait on July 5, 1994. Each of these patents is incorporated herein by reference.

Figure 6 shows a projected view of an alternative embodiment of the diaper backsheet of the present invention, with the portion of the backsheet positioned adjacent the absorbent center facing the observer. As shown in Figure 6, the backing sheet 247 comprises two layers 250 and 252. The layers 250 and 252 can be secured together by any suitable joining means as described above. In this embodiment, layer 250 forms the outer surface of the diaper and layer 252 is placed adjacent to the absorbent center. Since the layer 250 the portion of the backing sheet 247 will be in contact with the wearer's skin, the layer 250 is preferably smooth and comprises a nonwoven web. In addition to being soft, layer 250 is preferably permeable to wet steam. Layer 250 preferably exhibits a wet steam transmission rate of at least 2000 g / m2 / 24 hr., More preferably at least about 2500 g / m2 / 24 hr. Since layer 250 does not need to prevent leakage of absorbed exudates and contents within the absorbent center, the selection of materials that provide the desired softness and ventilation is widely extensive. Suitable materials include, but are not limited to, nonwoven webs such as interlaced spinning networks, fused networks, carded networks and the like. The non-woven webs for the layer 250 can comprise synthetic fibers, natural fibers, multi-component fibers such as bi-component fibers, or mixtures and mixtures thereof.

The layer 252 is the portion of the backsheet 247 which will prevent the exudates absorbed and contained in the absorbent center from the body exudate absorption articles which are in contact with the diaper. In order to protect the user from unwanted leaks of absorbed exudates and contents within the absorbent center layer 252, it must have larger width and length dimensions than those of the absorbent centers. If layer 252 is not large enough, exudates absorbed and retained in the center can find their way through the outer layer 250 during normal conditions of use. In the embodiment shown in Figure 7, the absorbent center is preferably positioned in the main panel 80 and extends within the middle panels 86 and 86 '. Accordingly, the layer 252 placed within the center is placed in the main panel 80 and extends within the middle panels 86 and 86 '. Layer 252 has dimensions of length and width at least as large as those of the absorbent center and preferably larger than those of the absorbent center. If desired, the layer 252 may extend beyond the main panel 80 and the middle panels 86 and 86 'to the leg panels 82, the waist band panels 88 and 88', and the side panels 90 and 90 '. In addition, the layer 252 may extend laterally and longitudinally outward of the main panel 80 to form the periphery portions of the disposable diaper.

While the layer 250 provides a substantial amount of wet vapor permeability, the layer 252 must also be permeable to wet steam in order to provide additional comfort for the user. In the embodiment of the invention shown in Figure 6, the layer 252 is comprised of the composite sheet 10 described above.

While a currently preferred embodiment of an absorbent article such as a diaper 50 according to the present invention uses a composite sheet 10 according to the present invention for substantially the total extension of the backing sheet 47, it is understood that the absorbent articles do not they are in no way limited to such modality. For example, a backsheet could be constructed of multiple backsheet elements having similar or diverse properties and constructions as described above with respect to Figure 6. One of the experiments would be to form a backsheet with a surface externally oriented of a composite or unitary nonwoven layer as a substrate with the sheet layer comprising only the region of the backing sheet where fluid insensitivity is desired, such as, for example, the region corresponding to region 252 depicted in Figure 6.

In addition, it may also be desirable for certain applications to return the orientation of layers 250 and 252 of Figure 6 in order to place the sheet layer on the clothing facing or outer side of the backing sheet and the fibrous substrate layer on the outside. the side facing the absorbent center of the backing sheet. It may likewise be desirable to use the composite sheet 10 in the double-sided embodiment of Figure 2 where both sides of the backing sheet would face the fibrous layer. All of these variations are contemplated to be within the scope of the present invention. In addition, depending on the specific application, the properties provided by the composite sheet of the present invention can also be used for better advantages in other regions of both sides of the absorbent article the central portion of the back sheet which covers the structure of the absorbent center . For example, the desirable properties of liquid insensitivity, wet vapor sensitivity of the composite sheet also provide desirable attributes to the peripheral portions of the absorbent article which extends laterally outward from the marginal ends of the absorbent center such as the side panels 90. , 90 'represented in Figure 5. Other "peripheral portions" of the absorbent article for which such attributes may be desirable are in the vicinity of the leg panels 82 which include but are not limited to several bands, folds and wings.

Otherwise, while much of the foregoing discussion focuses on the absorbent article in the diaper form 50, it is understood that the materials and principles of the present invention are equally applicable to other absorbent articles such as incontinence briefs, underwear for incontinence, fasteners and lining for diapers, feminine hygiene products (sanitary napkins, pantiliners, etc.), underpants trainers, clothes with detachment accessories, and the like where the materials of the present invention can be used advantageously. As a means of illustration, a backsheet of a sanitary napkin according to the present invention could be formed of a composite sheet of the present invention, as could the peripheral portions of a sanitary napkin such as wings or side wings.

After the manufacture of the composite sheet 10, and before or after incorporation of the sheet into the absorbent article, it may be desirable to secure the sheet to a mechanical post-forming process such as tensioning, tensioning / activation by rolling with corrugated rolls. , in another way. A representative process is described in detail in U.S. Patent No. 5,518,801 by Chappell et al., The disclosure of which is incorporated herein by reference.

The following non-limiting examples are intended to illustrate the products and process of the invention and do not limit the present invention in any way.

EXAMPLES In the above description and in the non-limiting examples that follow, the following methods were employed to determine various characteristics and properties reported. ASTM refers to the American Society for Testing and Materials, TAPPI refers to the Technical Association of the Pulp and Paper Industry, and ISO refers to the International Organization for Standardization.

Base Weight was determined by ASTM D-3776, which is incorporated herein by reference, and reported in g / m2.

The Thickness of the Composite Sheet was determined by the method ASTM D1777-64, which is incorporated herein by reference, and reported in microns.

The Thickness of the Film was reported in microns, and was determined as follows: Thickness (weight sample of l (base weight of (sample area) of the composite sheet) substrate) film (area of the sample) (density of the film material) Strength to the Stress was determined by ASTM 1682, section 19, which is incorporated herein by reference, with the following modifications. In the test, a 2.54cm by 20.32cm (1 inch by 8 inches) sample was held on opposite sides of the sample. the tweezers were set 12.7 cm (5 inches) apart from each other in the sample. The sample was pulled at a rate of 5.08 cm / min (2 inches per minute) until the sample broke. The breaking force was recorded in Newtones / cm as the tensile strength.

The Elongation to the Breaking of the sheet is a measure of the amount that a sheet is stretched before it fails (breaking) in a tensile stress test. A 1.0 inch (2.54 cm) wide sample was mounted on the tweezers - set 5.0 fleas (12.7 cm) apart - at a constant velocity of 2.0 inches / min (5.08 cm / min) to failure. The measurements were given in stretch percentage before failure. The test generally follows ASTM D-1682-64.

The peel strength of the top layer was measured according to a test that generally follows the method of ASTM D 2724-87, which is incorporated herein by reference. The test was developed under two different conditions, both using a constant speed of the tension test machine by extension such as the Instron test table.

According to what is defined as Test Condition A, which was used in Examples 1-17 and in the discussion portion of the specification, a sample of 2.54 cm (1.0 inches) by 20.32 cm (8.0 inches) the top sheet was removed approximately 3.18 cm (1.25 inches) by inserting a peak into the cross section of the sample to initiate a separation and then manually removing the sheet. Sample surfaces without foil were mounted on the tester pliers which were set at 2.54 cm (1.0 inches) apart. The tester was started and run at a cross-directional speed of 5.08 cm / min. (2.0 inches / min.). The computer initiated the collection of readings after the loose part was removed by approximately 1.27cm (0.5 inches) of movement in the transverse direction. The sample was delayed by approximately 15.24 cm (6 inches) during which approximately 3000 readings were taken and the average. The resistance to average delamination was given in N / cm. A suitable method to start the loss of the top sheet is to immerse the end of a sample in isopropyl alcohol to swell the sample, which is being peeled manually, and then removing and discharging the portion of the sample brought into contact with the alcohol before measuring the resistance to separation of the top layer.

In accordance here is defined as Test Condition B which is used in Examples 18-34, the method for Test Condition A is used except that the samples are 15 cm (6 inches) long, a speed was used in the transverse direction of 10 inches / min., the detachment was initiated manually instead of with a peak, and the resistance to delamination was recorded from the average indicated on the registration letter.

The Humid Steam Transmission Speed (MVTR) was determined by one of the two methods. The first method used follows ASTM E96-B, which is incorporated herein by reference, and is reported in g / m2 / 24 hr.

The second method is referred to as a desiccant method for measuring the wet steam transmission rate as set forth above. Briefly summarizing this method, a known amount of desiccant (CaCl2) is placed inside a "bowl" with tabs similar to a container. The sample material is placed on top of the container and secured by a ring and a retaining gasket. The assembly was then weighed and recorded as the initial weight. The assembly was placed at a constant temperature of (40 ° C) and humidity of the chamber (75% RH) for five (5) hours. The assembly was then removed from the chamber, sealed to prevent more moisture from entering, and allowed to equilibrate for at least 30 minutes at room temperature where the balance was placed. The amount of moisture absorbed by CaCl2 was determined gravimetrically and was used to estimate the wet vapor transmission rate (MVTR) of the sample by weighing the assembly and recording the final weight. The moisture vapor transmission rate (MVTR) was calculated and expressed in g / m2 / 24 hr. using the formula below. A reference sample, of the established permeability, was used as a positive control for each batch of samples. Samples were tested in triplicate. The MVTR reported is the average of the triplicate analyzes, rounded to the nearest 100. Significant differences in the MVTR values found for different samples can be estimated based on the standard deviation of the triplicate assays for each sample. The Analytical Balances suitable for the development of the measurements include an AE240 Tester or equivalent (300 g capacity) or a Sartorius 2254S0002 or equivalent (1000 g capacity). A suitable sample to ensure assembly comprises a bowl and retaining ring manufactured by Delrin® (which are available from McMaster-Carr Catalog # 8572K34) with a gasket made by GC Septum Material (Alltech catalog # 6528). The desiccant comprises CaCl2 for U-tubes, available from Wako Pure Chemical Industries, Ltd., Richmond VA. Product # 030-00525. The plastic-fed cover comprises Saran's Cover, available from the Dow Chemical Company, or equivalent.

CaCl2 can be used directly from a sealed bottle as long as the size of the clods does not pass through a No. 10 screen.

Usually two-thirds of the top of the bottle does not have to be sifted. However, the third part that contains fines must be removed by sieving. CaCl2 can be used by a closed container without drying. This can be dried at 200 ° C for 4 hours if required.

The Exxon Exxaire microporous material, Catalog # XBF-100W, is used as a Standard Reference Material. The triplicate samples should be prepared and analyzed together with each group of test samples as described below.

Representative samples must be obtained from the materials to be tested. Ideally, these samples should be taken from different areas of the material in order to represent any present variation. Three samples of each material are needed for this analysis.

Samples should be cut into rectangular pieces approximately 1.5"x 2.5". If the samples are not uniform, clearly mark the area which ventilation will be evaluated. If the samples are not bidirectional, clearly mark the side that was exposed to high humidity. For examples used in diapers and articles for feminine hygiene, this is usually the side that is in contact with the skin.

To start a test session, (1) weight . 0 ± 0.02 in grams of CaCl2 and placed in the MVTR bowl. Gently tap the bowl 10 times on the top tab to distribute and lightly pack the CaCl2. The CaCl2 should be at a level and approximately 1 cm from the top of the bowl. Then (2) place the sample, with the high humidity side facing up (if required), over the hole in the top of the bowl. Be sure that the sample is superimposed on the hole in order to obtain a good seal. Next, (3) place the sealing material and retaining ring on top of the bowl, aligning the holes with the screws and making sure that the samples have not moved. Tightening the screws to secure the retaining ring and seal the sample on top of the bowl. Care must be taken not to over tighten the screws so that this causes the distortion of some samples. If the distortion of the samples occurs, the screws are released and tightened again. Then (4) weigh the MVTR bowl assembled in step 3. This weight is recorded as the initial weight.

After weighing the assembly, (5) place the sample in the CT / CH chamber for 5.0 hours (at the nearest minute). When the time has passed, (6) Remove the sample from the CT / CH chamber, tightly cover it with a plastic cover secured by a rubber band. The time of removal of the sample is recorded within the nearest minute. The samples are allowed to equilibrate for at least 30 minutes at room temperature where the balance is made. After balancing, (7) remove the Saran's cover and weigh the bowl. This weight is recorded as the final weight.

Then the MVTR is calculated in units of gH20 / 24 hr / m2 using the formula: (initial weight-final weight) x24 MVTR = area of the sample in meters x 5.0 (time in the camera) where: 24.0 is used to convert the date to the base time; the area of the sample is equal to the area of the mouth of the bowl; Y . 0 is the duration of the test in hours.

The average MVTR is calculated for each group of samples in triplicate and the standard reference. Rounding the average MVTR for the standard reference to the nearest 100. If the MVTR for the standard reference is in the range of 4000 to 4600 it is in the range of acceptable quality control and the results for this day can be reported. Rounding the average MVTR for each group of samples to the nearest 100. This value is reported as the MVTR for the material sample. Steps 1 through 7 are repeated for the triplicate analyzes of each sample and the standard reference. Typically, multiple samples are processed in parallel.

The Dynamic Transmission of the Fluid was measured with the apparatus 100 shown in Figure 7. According to this test, an absorption material 102 was weighed by approximately 0.0001 grams was placed directly on the top of the impact energy absorption pad 103. The absorption material 102 may comprise a filter paper No. 2 available from Whatman Laboratory Division, Distributed by VWR Scientific of Cleveland, OH. The absorption material must be capable of absorbing and retaining simulated urine which passes through the laminar material being tested. The impact energy absorbing pad 103 is a rubber foam with a transverse link filled with black carbon. The impact pad of 5 inches by 5 square inches have a density of 0.1132 g / cm3 and a thickness of 0.3125 inches. The impact pad 103 has a Durometer Value of A / 30/15 according to ASTM 2240-91. A circular absorbent center material 104 measuring 0.0635 meters (2.5 inches) in diameter was weighed. The absorbent center material may comprise interlaced wood pulp cellulosic fibers, individualized as described in US Patent No. 5, 137,537 published by Heron et al. on August 11, 1992. The absorbent center material must be capable of ensuring a sufficient amount of simulated urine, for example, at least both ten times its dry weight. The absorbent center has a basis weight of approximately 228 g / m2. The absorbent center material is then loaded with simulated urine for approximately ten times its dry weight. The simulated urine is an aqueous composition, maintained at 37 ° C, and comprised of the following compounds dissolved in distilled water: 2.0 g / L of KCl; 2.0 g / L Na2S04; 0.85 g / L (NH4) H2P04; 0.15 g / L of (NH4) 2H2P04; 0.19 g / L CaCl2; and 0.23 g / L MgCl2.

A section of the material of the backing sheet 105 to be tested is placed face down with the outside surface on the top of a clean, dry table. The loaded center material 104 is placed directly in the center of the material of the backing sheet 105. The backing / center sheet arrangement is then secured to the impact portion 107 of the impact arm 108 with a rubber band 109. arrangements of the backing sheet / center is positioned such that the center 104 is adjacent to the bottom surface 110 of the impact portion 107. The impact arm 108 is raised to a desired impact angle to provide the desired impact energy. The impact arm 108 is dropped and the impact arm 108 is then raised immediately (approximately 1 second after impact) and the filter paper 102 is removed and placed on a digital scale. The mass of the moist filter paper is then registered at the three minute mark. The dynamic fluid transmission value (DFTV) is calculated and expressed in g / m2 using the following formula: filter paper mass - wet filter paper mass (grams) dry (grams) DFTV = impact area (m2) The area of impact, expressed in m2, is the area of the surface of the lower part 110 of the impact portion 107. The impact area is 0.00317 m2. The material of the absorbent center 104 should have an area slightly larger than the impact area of the surface 110.

Gurvey Hill Porosity is a measure of the barrier strength of the laminar material for gaseous materials. In particular, this is a measure of how long it takes a gas volume to pass through an area of material where a certain pressure gradient exists. The Gurley-Hill porosity was measured according to TAPPI T-460 om-88 using a Lorentzen & Wettre Model 121D. This test measures the time in which 100 cubic centimeters of air is pushed through a one-inch diameter sample under pressure of approximately 4.9 inches of water. The result is expressed in seconds and usually referred to as Gurley Seconds.

Sterile Microbial Barrier Packaging is measured in accordance with ISO 11607 which states under section 4.2.3.2 that a material that is impervious to air for one hour (according to an air porosity test) satisfies the requirements as a microbial barrier standard. With respect to porous materials, section 4.2.3.3 of ISO 11607 states that there is no universal method applicable to demonstrate the properties of microbial barrier in porous materials is typically directed for difficult samples with a spore aerosol of bacteria or particularly under a group of test conditions which specify the flow velocity through the material, the microbial challenge for the sample, and the duration of the test. One of the recognized tests is ASTM F 1608-95.

Liquid Filtration is detected using a solution of 70 parts of isopropyl alcohol, 30 parts of water and 1 part of color for red dye foods. According to this test, a sheet of white absorbent blotting material measuring approximately 89 cm by 61 cm (35 inches by 24 inches) is placed on a flat surface and covered with a test sample of the same dimensions with the side of the up sample substrate. A 250 ml portion of the solution is poured onto the surface of the test sample and covered with a measuring template of approximately 46% by 46 cm (18 inches by 18 inches). A 4.5 kg (10 lb) weight is placed on top of the template for 10 minutes after which the weight, template and test sample are removed from the white blotter. The paper is then inspected for ink stains to determine if filtration occurred.

EXAMPLE 1 A composition was prepared by dry blending 86% by weight of a thermoplastic copolyether ester elastomer (Hytrel® 4778 obtained by DuPont) with 4% by weight of a UV stabilizer concentrate (Hytrel® 20UV, obtained by DuPont), 4% by weight of a heat stabilizer concentrate (Hytrel® 30HS obtained by DuPont), and 6% by weight of a polyolefin copolymer modified with maleic anhydride (Fusabond® 373 obtained by DuPont Canada). Fusabond® is a registered trademark of DuPont Canada. The composition was fed to a melt extrusion coating line that includes a single screw extruder with an initial mixing receptacle. The screw extruder was made by Egan Division of Davis Standard Corporation. The heating zones of the extruder heat the polymer to a temperature above its melting point. The molten polymer mixture was fed to a die in the form of a film with a width of approximately 90 cm which was maintained at approximately 220 ° C. The polymer was laminated on a non-woven polypropylene fabric with corona treatment (Typar® thermally bonded polypropylene obtained by DuPont) at a line speed of 18.3 m / min. The molten polymer and the non-woven fabric were passed through the pair of compression rollers (a roller with rubber surface against the non-woven fabric and a roll with steel surface against the molten polymer). The resulting laminate had a coating thickness of approximately 25 microns and the peel strength values of the upper surface of 0.063 N / cm in the machine direction (MD) and 0.032 N / cm in the transverse direction (CD) and an MVTR value of 700 g / m2 / 24 hr., (for example ASTM E96-B).

EXAMPLE 2 The Typar® non-woven fabric of Example 1 was placed with a non-woven polyester fabric (compatible with ester copolymer polymer) (obtained by Freudenberg, Germany) and the resulting laminate had peel strength values of 0.88 N / cm ( MD) and 1.06 N / cm (CD) and an MVTR value of 750 g / m2 / 24 hr (by the method ASTM E96-B).

EXAMPLE 3 A composition was prepared by dry blending 70% by weight of a thermoplastic copolyether ester elastomer (Hytrel® 8206 obtained by DuPont) with 4% by weight of a UV stabilizer concentrate (Hytrel® 20UV, obtained by DuPont), 4% by weight of a heat stabilizer concentrate (Hytrel® 30HS obtained by DuPont), 8% by weight of a polyolefin copolymer modified with maleic anhydride (Fusabond® 373) and 14% by weight of a polypropylene polymer resin (PF331 obtained by Montell Polyolefins, Wilmington, Delaware). The mixture was extruded under the same conditions as described in Example 1 and the melt was laminated on the same Typar® nonwoven fabric described in comparative example 2. The resulting laminate had a coating thickness of approximately 25 microns and a value of peel strength of 0.26 N / cm (MD) and 0.18 g / cm (CD) and an MVTR of 800 g / m2 / 24 hr (by the method ASTM E96-B).

EXAMPLE 4 One composition was prepared by dry blending of 80% by weight of a thermoplastic copolyether ester elastomer (Hytrel® 8206) with 9.3% by weight of polypropylene resin (PF331 obtained by Montell Polyolefins, Wilmington, Delaware), 4.7% by weight of PELLD (Novapol 8111) obtained by Novacor Chemicals Inc., Leominster, Massachusetts), 4.7% by weight of an HDPE containing 30% by weight of CaC03 with a particle size of 1 micron (Zemid ™ 610 obtained by DuPont Canada, Missassauga, Ontario ) and 1.3% by weight of a polyolefin copolymer modified with maleic anhydride (Fusabond® MD353D). The Zemid ™ is a registered trademark of DuPont Canada. The mixture was extruded under the same conditions as described in example 1 at a line speed of 14 m / min. and the melt was laminated to the non-woven HDPE fabric by a corona treatment, joined by fabric made by Corovin GmbH, of Peine, Germany. The resulting laminate had a coating thickness of approximately 31 microns, a peel strength of 0.64 N / cm, a tensile strength of 9.1 N / cm (MD) and 3.6 N / cm (CD), and an MVTR of 907 g / m2 / 24 hr. , (by the method ASTM E96-B).

EXAMPLE 5 Example 4 was repeated at a line speed of 23 m / min., Resulting in a laminate having a coating thickness of approximately 20 microns and peel strength 0.18 N / cm and an MVTR of 1011 g / m2 / 24 hr ( by the method ASTM E96-B).

EXAMPLE 6 One composition was prepared by dry blending of 50% by weight of a thermoplastic copolyether ester elastomer (Hytrel® 8206) with 33% by weight of copolyether ester thermoplastic elastomer (Hytrel® G3548W obtained by DuPont), 8.0% by weight polypropylene (PF331), 2.6% by weight of PE-LLD (Novapol 8111), 5.4% by weight of an HDPE containing 30% by weight of CaC03 with particle size of 1 micron (Zemid ™ 610) and 1.0% by weight of a modified polyolefin copolymer with maleic anhydride (Fusabond® MD353D). The mixture was extruded under the same conditions as described in Example 1 at a line speed of approximately 24 m / min. and the melt was laminated to the non-woven HDPE fabric used in Example 4. The resulting laminate had a coating thickness of approximately 20 microns and the peel strength values of 0.09 N / cm and an MVTR of 1159 g / m2 / 24 hr. , (by the method ASTM E96-B).

EXAMPLE 7 A composition was prepared by dry blending 50% by weight of a thermoplastic ester copolyester elastomer (Hytrel® 8206) with 31% by weight of another thermoplastic ester copolyester elastomer (Hytrel® 8171 obtained by DuPont), 8.9% by weight of polypropylene (Fine 3365 obtained by Fina Oil and Chemical of Dallas, Texas), 2.9% by weight of PELLD (Novapol 8111), 6.1% by weight of CaC03 with particle size of 1 micron (Zemid ™ 610), and 1.1% by weight of a polyolefin copolymer modified with maleic anhydride (Fusabond ® MD353D). The mixture was extruded onto a non-woven, polyethylene, corona treated, spunbonded fabric made by Polybond of Waynesboro, Virginia and adhered to the non-woven by means of a vacuum process. The resulting laminate had a coating thickness of approximately 15 microns and a peel strength of 0.05 N / cm and an MVTR of 1409 g / m2 / 24 hr (by the ASTM E96-B method).

EXAMPLES 8-17 The film compositions described below were prepared by dry blending two thermoplastic ester copolyether elastomers, an anhydride modified polypropylene or an anhydride-modified ethylene vinyl acetate, and titanium dioxide. The individual compounds in the portions of the film were as follows: The Hytrel® 8206 thermoplastic ester copolyester elastomer sold by DuPont, and having a melting point of 200 ° C, a softening temperature of 151 ° C, and a final hardness of 45D.

The Hytrel® 8171 thermoplastic ester copolyester elastomer sold by DuPont, and having a melting point of 150 ° C, a softening temperature of 76 ° C, and a final hardness of 32D. * The Bynel® 50E561 polypropylene modified with anhydride sold by DuPont, and having a melting point of 141 ° C, a softening temperature of 109 ° C.

The Bynel® 50E555 polypropylene modified with anhydride sold by DuPont, and having a melting point of 166 ° C, a softening temperature of 144 ° C.

The Bynel® 3860 ethylene modified vinyl acetate with anhydride sold by DuPont, and having a melting point of 74 ° C, a softening temperature of 48 ° C.

The TiQ2 Concentrate was a concentrate of 50% by weight of pigment particles of titanium dioxide in high density polyethylene.

The compositions of the film used in examples 8-17 had the following compositions: Composition of A B c D E film Hytrel® 8206 49% 49% 40% 41% 34% Hytrel® 8171 32% 32% 40% 43% 50% Hytrel® 50E561 13% - - - __ Hytrel® 50E555 - 13% 14% - - Hytrel® 3861 - - - 10% 10% Concentrate 6% 6% 6% 6% 6% Ti02 Each of the compositions was fed to a melt extrusion coating line that includes a screw extruder with a fixed mixing receiver. The screw extruder was made by Egan Division of Davis-Standard Corporation. The compositions were fed to the extruder where the temperature was increased to about 263 ° C and a pressure of 3827 kPa. The melts were fed to a die in the form of a film with a width of approximately 80 cm which was maintained at approximately 220 ° C.

The compositions of the molten polymer were laminated onto carded polypropylene fiber sheets, with fiber lengths in the range between 2.5 and 7.5 cm which had been thermally bonded and placed in the air. The polypropylene fiber layer had a basis weight of 0.0305 Kg / m2 (0.9oz / yd2), a tensile strength of 8.3 N / cm (4.73 lb / inch) in the machine direction and 1.5 N / cm (0.861b / inch) in the transverse direction, and an elongation of 73% in the machine direction and 95% in the transverse direction. The polypropylene fiber sheet was spaced 24.1 cm (9.5 inches) from the die opening and the sheet moved at a line speed of 32 m / min. during the lamination. The molten polymer and the polypropylene fiber sheet were passed through a pair of compression rolls (a roll with metal surface against the fibrous sheet material and a roll with rubber surface against the molten polymer). The metal roll was maintained at approximately 43.3 ° C (110 ° F) by cooling water. The air cylinders were used at a pressure of 414 kPa (60 psi) to press the rolls together. The resulting composite sheets had the properties set forth in Table 1 below.

Table 1 Example 8 9 1 0 1 1 1 2 1 3 1 4 1 5 1 6 1 7 Composition ae AABECCDDEE film Thickness 20 25 20 25 20 25 20 25 20 25 film (my crones) Thickness 165 165 173 170 170 160 155 155 150 160 composite (mm) MVTR (method 3418 3051 3486 3536 3651 3346 4246 3489 3444 3255 Desiccant) (g / m "/ day) Impact 0.36 0.31 0.28 0.37 0.16 0.04 0.12 0 0 0 Dynamic (g / ml 2400J / m) Resistance to desprinting in all All to (N / cm) MD 0.41 0.73 0.34 0.59 0.47 0.38 0.47 * 0.27 * CD 0.33 0.53 0.36 0.39 0.29 0.43 0.57 0.37 0.41 0.66 Resistance to tension (N / cm) MD 11.7 13.7 11.4 11.7 13.1 14.4 10.2 9.8 10.5 11.7 CD 2.5 2.3 2.3 2.5 1.8 2.1 1.8 2.1 1.8 1.9 (%) Elongation MD 61 66 88 80 67 60 60 80 65 66 CD 103 106 104 81 106 67 108 96 107 109 Filtration by nin-ninety-ninety-ninety-nin- nin-nin orifices guna guna guna guna guna guna guna guna guna guna tiny porosity at > > - - > > - - > > Air Gurley 3600 3600 3600 3600 3600 3600 Hill (se) 'Resistance to detachment had a total union > 0.75 N / cm EXAMPLES 18-31 Examples 18-31 were directed to determine the effect of various process conditions on the properties of the composite sheet. Examples 18-30 do not attempt to optimize the properties of the final products. One composition was prepared by dry blending 50% by weight of (Hytrel® 8206) with 33% by weight of Hytrel® 8171, 4% by weight of another thermoplastic ester copolyester elastomer.

(Hytrel® 4056 sold by DuPont, has a melting point of 150 ° C, a softening temperature of 108 ° C, and a final hardness of 40D) containing 50% by weight of titanium dioxide Ti-Pure® R960 and 13% by weight of Bynel® 50E561. Titanium dioxide Ti-Pure® R960 is a registered trademark of DuPont. The composition was fed to a melt extrusion coating line that includes a single screw extruder that ran at 20 rpm. with a helical screw configuration. The zones of the extruder were heated to a temperature set forth in Table 2. The molten polymer mixture was fed to a die in the form of a film with a width of about 35 cm which was maintained at the same temperature as the extruder. The mixture was extruded under the conditions set forth in Table 2, below, on a moving fibrous sheet. The composition of the film joined the fiber sheet in one compression, as shown in Figure 3, this was spaced approximately 9 cm (3.5 inches) from the opening of the die.

The fibrous sheet was a carded nonwoven ("C") or a spunbonded nonwoven ("S"). The carded sheet was made of carded polypropylene fiber, with fiber lengths generally in the range between 2.5 and 7.5 cm which had been thermally bonded and placed in the air. The polypropylene fiber sheet had a basis weight of 0.0305 kg / m2 (0.9oz / yd2), a tensile strength of 8.3 N / cm (4.73 lb / inch) in the machine direction and 1.5 N / cm (0.861b / inch) in the transverse direction, and an elongation of 73% in the machine direction and 95% in the transverse direction. The spin-bonded sheet was made of spin-linked polypropylene with a basis weight of 0.0288 kg / m2 (0.85 oz / yd2), a tensile strength of 11.4 N / cm (6.5 lb / inch) in the machine direction and 2.5 N / cm (1.41b / inch) in the transverse direction, and an elongation of 92% in the machine direction and 93% in the transverse direction. In the Examples in Tables 2 and 3 the "corona treatment" was indicated, before the fibrous sheet and the wet vapor permeable film were bonded, the fibrous sheet was passed at a sheet speed of 15 m / min. through a Corona Surface Treatment Machine Model RX-8 manufactured by ENI Power Systems, Inc., this was set at a frequency of 25 kHz, and a power of 500-600 Watts.

The processing parameters were controlled to determine how much the impacted individual processing conditions changed in the properties of peel strength, moisture vapor transmission, and dynamic barrier of the sheet.

Examples 18-21 together show how increasing the temperature of rolls 34 and 36 improves the peel strength of the composite sheet.

Examples 18, 22 and 23 together show how increasing the temperature of the die 38 during which the composition of the film was extruded improves the peel strength of the composite sheet.

Examples 24-26 together show how increasing the thickness of the film by decreasing the line speed improves the peel strength of the composite sheet.

Examples 25 and 27 together demonstrate how the use of more fibrous carded sheet material improves the peel strength of the composite sheet.

Examples 28, 29 and 30 show how increasing the temperature of the compression rollers 34 and 36 (Figure 3) improves the peel strength of the sheet, but also reduces the transmission of wet steam through the composite sheet. Measurements of Differential Scanning Calorimetry of the heat of fusion suggest that at lower temperatures in the rolls of Example 28, the morphology of the film is more amorphous, when compared to a morphology of more crystalline film generated at high temperatures of the rolls of the film. Example 30. Thus, it seems that a morphology of the more amorphous film is generated with lower temperatures resulting in a higher rate of wet steam transmission.

Examples 25 and 31 show how increasing the pressure applied against the compression rollers 34 and 36 improves the peel strength of the sheet. In Example 31, a pressure of 138 kPa (20 psi) was used in the pneumatic system to press the roller 34 against the roller 36. In Example 25, all the process conditions were the same as in Example 31 except that the pressure was 550 kPa (80 psi), so it was also applied in Examples 18-30, such that the compression force in Example 25 was significantly greater than the compression force in Example 31. The increased compression force caused an increase in the resistance to detachment.

Table 2 E ng 18 19 20 21 22 23 24 Temperature of 40 15 76 115 42 42 40 Roai lio in the compression ion (° C) Temperature of 220 220 220 220 240 260 220 Extrusion die (° C) Line speed 13 13 13 13 13 13 18 (m / min.) Composition of the C substrate Corona treatment YES YES YES YES YES YES YES NO Thickness of the 22 22 22 ~ 22 26 ~ 22 16 Film (microns) Resistance to 0.06 0.04 0.25 All 0.27 All 0.01 detachment (N / cm) Dynamic Impact 0.0 0.0 0.0 87 * 0.01 1.34 * 0.07 (g / m ¿1 2400 J / m¿) MVTR (g / m2 / 24h) 2700 260Q 240Q 260Q 24Qo 23OQ 3IOQ Table 2 (continued; Example 25 26 27 28 29 30 31 Temperature of the 40 40 40 10 40 60 40 roller in the (pre-compression (° C) ion 138 kPa) Temperature of 220 220 220 220 220 220 220 Extrusion Die (° Cj Line Speed 13 10 13 13 13 13 13 (m / min.) Composition of the substrate Treatment Corona NO NO NO YES YES NO Thickness of the 23 29 21 22 30 28 Film (micron) Resistance to 0.07 0.23 0.03 0 # 0.23 0.61 0.04 detachment (N / cm) MVTR (g / u '/ 24 hr) 2600 2400 2800 2800 2700 2500 2800 Dynamic Impact 0.0 0.13 0.1 0.03 0.28 0.08 (g / m ¿I 2400 J / m) I do not know why / 1 Os eg sharp 'Tiny holes present due to excessive union # Had adhesion to the small roller, could have reduced the detachment EXAMPLES 32-34 A composition of the film was prepared by dry mixing 57.5% by weight of a thermoplastic copolyether ester elastomer (Hytrel® 8206) with 38% by weight of another thermoplastic ester copolyether elastomer (Hytrel® 8171), and 4.5% by weight of another thermoplastic ester copolyester elastomer (Hytrel® 4056) containing 50% by weight Ti-Pure® R960 titanium dioxide. The composition was fed to a melt extrusion coating line that includes a single screw extruder that ran at 20 rpm. with a helical screw configuration. The zones of the extruder were heated to a fixed temperature of 220 ° C. The mixture of molten polymers was fed to a die in the form of a film with a width of 35 cm which was maintained at 220 ° C. The mixture was extruded under conditions set forth in Table 3, below, on a moving fibrous sheet. The composition of the film attached to the fiber sheet in one compression, as shown in Figure 3, was spaced approximately 9 cm (3.5 inches) from the die opening.

The fibrous sheet was a carded nonwoven ("C") made of the carded polypropylene fiber, with fiber lengths generally in the range between 2.5 and 7.5 cm that had been thermally bonded and placed in the air. The polypropylene fiber sheet had a basis weight of 0.0305 kg / m2 (0.9 oz / yd2), a tensile strength of 8.3 N / cm (4.73 lb / inch) in the machine direction and 1.5 N / cm ( 0.861b / inch) in the transverse direction, and an elongation of 73% in the machine direction and 95% in the transverse direction. The processing conditions were optimized such that the peel strengths were obtained from 0.08 to 0.29 N / cm without the addition of a polyolefin or a compatibilizer to the polyether ester polymer of the moisture permeable sheet material.

Table 3 Example 32 33 34 Temperature of 40 40 40 roll in compression (° C) Temperature of 220 220 220 Extrusion die (° C) Speed of 13 13 13 Line (m / min.) Composition of the substrate Treatment SI SI SI Corona Thickness of the 31 24 25 Film (my orones) Resistance to 0.29 0.08 0.10 detachment (N / cm) MVTR 3600 3600 3500 (g / m '/ 24 hr) Dynamic Impact 0. or 0. or 0. o (g / m I 2400 J / m ") EXAMPLE 35 A composition was prepared as in Examples 19-31. The composition was fed to a melt extrusion coating line that includes a single screw extruder that ran at 20 rpm. with a helical screw configuration. The zones of the extruder were heated to a fixed temperature of 220 ° C. The mixture of molten polymers was fed to a die in the form of a film with a width of 35 cm which was maintained at 220 ° C. The mixture was extruded under immediately exposed conditions, between two moving fibrous sheets. The composition of the film attached to the fiber sheet in a compression, as shown in Figure 3. However, a fibrous sheet was fed into the compression in each of the rolls 34 and 36, and both fibrous sheets They joined the movie in compression. The compression opening was spaced approximately 9 cm (3.5 inches) from the die opening.

Each of the fibrous sheets was a carded nonwoven ("C") made of the carded polypropylene fiber, with fiber lengths generally in the range between 2.5 and 7.5 cm that had been thermally bonded and placed in the air. The polypropylene fiber sheet had a basis weight of 0.0305 kg / m2 (0.9 oz / yd2), a tensile strength of 8.3 N / cm (4731b / inch) in the machine direction and 1.5 N / cm ( 0.86 lb / inch) in the transverse direction, and an elongation of 73% in the machine direction and 95% in the transverse direction. The composite sheet formed was similar to that shown in Figure 2. The processing conditions and product properties are listed in Table 4 below.

Table 4 example 35 Temperature of roll 70 in compression (° C) Die temperature and 220 Extruson (° C) Line speed 13 (m / min.) Composition of substrate C (both sides) Corona treatment SI Thickness of Film 24 (microns) Resistance to 0.11 (side A) detachment (N / cm) 0.16 (side B) MVTR 2300 (g / nX / 24 hr) Dynamic Impact (g / m28 0.10 2400 J / mX EXAMPLES 36-39 A first polymer composition was prepared as in Examples 19-31. This first polymer composition was fed to a 38 mm diameter extruder at a temperature of 220 ° C which was run at 20 r.p.m. The output of this 38 mm extruder was connected to a melt combination block. A second polymer composition comprised of 100% Hytrel® 4778 (melting point 208 ° C, softening temperature 175 ° C, and ultimate hardness 47 D) was fed to a 25 mm extruder was also connected to the same combination block of cast. This 25 mm diameter extruder was also operated at a temperature of 220 ° C. In Examples 36-39, the 25 mm extruder speed was varied from 20 r.p.m. at 1.5 r.p.m. to generate films where the thickness of the layer of the second polymer composition varied. the coextruded layers were combined in the melt combination block. The die had a width of the die block of 35 cm that was heated to approximately 220 ° C.

A bonded two-component film was formed and exited the die. The layer of the first polymer composition maintained a nominal thickness of approximately 22 microns in each of Examples 36-39. The thickness of the layers of the second polymer composition was between 4 and 0.2 microns. This film was joined with a hot melt adhesive in a spiral spray pattern to a 30.5 (1.2 mil) polyethylene film (by Tredegar Film Products) of the type used in the backing sheet of the absorbent articles. The hot melt adhesive was a SIS linear adhesive (Findley H2031) of the type currently used in diaper manufacturing.

To measure the "build-up resistance" of the resulting bond between the polyethylene film and the second polymer composition, 1-inch-wide strips of the two materials were prepared and surface-bonded to one another over an area by measuring a square inch, leaving a pair of opposite unattached wings on at least one end of the strips lengthwise to traverse the garment along the test unit. The adhesive used was a linear adhesive SI commercially available from Findley Adhesives under the designation H2031, was applied at an addition level of 0.009 grams / square inch in a spiral spray pattern. The three samples were prepared for each test sequence, with the reported results comprising an average of the results for the three samples. An Instron model test table with a 5-pound load cell, a garment length of 2 inches, and a cross-directional speed of 20 inches per minute was used, in a manner generally consistent with the Elongation test. Breakdown described above. The opposite non-union wings of the two materials were clamped in the respective clamps of the test apparatus, with the second polymer composition in the uppermost clamp. Specimens were evaluated at the point of failure when the delamination of the bound adhesive or the substrates themselves occurred.

Two-component / polyethylene film constructions were prepared according to the following conditions to obtain the following properties: Table 5 Example 3 6 37 3 8 39 Speed of 2 0 1 0 5 1. 5 Extruder (rpm) (extruder 25mm) Thickness of 1.7 0.7 0.2 second laminar layer (micron) MVTR of 2700 2800 2900 2900 two-component film (g / m Day) Resistance to 2.47 1.71 1.70 1.43 construction-Dry detachment (N / cm) Resistance to 1.78 1.93 1.73 1.63 construction-wet detachment * (N / cm) * The wet state means that the test is soaked in distilled water for 30 minutes.

COMPARATIVE EXAMPLE 1 A sample of Exxon Exxaon XFB-100W microporous film, available from Exxon Chemical Company of Buffalo Grove, Illinois, USA, tested the wet steam transmission rate, the dynamic fluid transmission, the microbial barrier for sterile packaging, and the filtration of liquid. The measured properties were the following: MVTR (g / m2 / 24 hr) 4000 Dynamic Impact (g / m2 § 0.97 2400 J / m2) Microbial barrier The passage of Bacillus subtilis bacteria was recorded in six of the six samples tested after 15 minutes of exposure. (vacuum of 38.6 cm Hg; flow rate of 2.8 L / min.) Apparent dry moisture filtration in the blotting paper that indicates the passage of liquid.

It will be apparent to a person skilled in the art that modifications and variations may be made in the ventilatable composite sheet material of this invention. The invention in its broader aspects, therefore, is not limited to the specific details or illustrative examples described above. Thus, it is intended that the entire subject contained in the aforementioned description, drawings and examples be construed as illustrative and not in essence limiting.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Having described the invention as above, the content of the following is claimed as property.

Claims

1. A composite laminar material, permeable to moist vapor, substantially impermeable to liquid, characterized in that it comprises a fibrous substrate and a thermoplastic laminar layer permeable to wet vapor; said fibrous substrate comprises a synthetic fiber, said synthetic fiber is comprised of at least 50% by weight of polyolefin polymer, said substrate having opposite the first and second planar sides; said wet vapor permeable laminar layer is directly melt bonded to the first side of said substrate; said composite sheet exhibits a peel strength of at least 0.1 N / cm, a dynamic fluid transmission of at least about 0.75 g / m2 when subjected to an impact energy of approximately 2400 joules / m2, and having a transmission speed of the wet steam, according to the desiccant method, of at least 1500 g / m2 / 24 hr.

2. The composite sheet of claim 1, characterized in that the sheet layer has an average thickness of less than about 50 microns.

3. The composite sheet of claim 2, characterized in that the sheet layer is comprised at least about 50% by weight of the polymer selected from the group of the copolyether ester block, block of copolyether amides, polyurethanes and combinations thereof.

4. The composite sheet of the claim 3, characterized in that said laminar layer is melt-bonded to the substrate in the absence of an adhesive between the laminar layer and the substrate.

5. The composite sheet of the claim 4, characterized in that said laminar layer has a peel strength of at least about 0.15 N / cm.

6. The composite sheet of claim 5, characterized in that said sheet layer has a peel strength per unit thickness of the sheet layer of the sheet material at least about 0.003 N / cm-micron.

7. The composite sheet of claim 5, characterized in that the sheet layer of said composite sheet has a thickness of at least 30 microns and the composite sheet has a wet steam transmission rate, according to the desiccant method, of at least 2500 g / m / 24 hr.

8. The composite sheet of claim 7, characterized in that the sheet layer of said composite sheet has a thickness between about 10 microns and about 25 microns, and the basis weight of said fibrous substrate is between about 13.5 and about 40 g / m2.

9. The composite sheet of claim 2, characterized in that the sheet layer has opposite the first and second sides, said first side is directly bonded by fusion to the first side of the substrate, and wherein said first of said first sheet layer has a surface area per unit. of area that is greater than the surface area per unit area of said second side of the sheet layer.

10. The composite sheet of claim 1, characterized in that said laminate has a dynamic fluid transmission of less than about 0.5 g / m2 when subjected to an impact energy of approximately 2400 joules / m2.

11. The composite sheet of claim 10, characterized in that the composite sheet is substantially free of micropores, and substantially no liquid passes through the sheet when tested according to the liquid filtration test.

12. The composite sheet of claim 10, characterized in that the composite sheet prevents the passage of microbes when this is tested according to the ISO 11607 standard for sterile packaging materials.

13. The composite sheet of claim 3, characterized in that said composite sheet has a tensile strength in the machine direction and a tensile strength in the direction of at least 1 N / cm, and an elongation in the machine direction and an elongation in the transverse direction of at least about 30%.

14. The composite sheet of claim 13, characterized in that said fibrous substrate consists essentially of polyolefin polymer fibers.

15. The composite sheet of claim 3, characterized in that said sheet layer comprises a vapor permeable film having multiple layers, each of these multiple layers being comprised of a wet vapor permeable thermoplastic polymer composition.

16. The composite sheet of claim 15, characterized in that one of said laminar layers comprises a substantially hydrophilic laminar layer and one of said layers comprises a substantially hydrophobic laminar layer.

17. The composite sheet of claim 1, characterized in that said composite sheet further includes an additional layer of various construction and composition of said sheet layer and said fibrous substrate.

18. The composite sheet of claim 17, characterized in that said additional layer comprises a microporous film.

19. The composite sheet of claim 1, characterized in that said sheet layer is comprised at least of about 50% by weight of a Fraction A consisting essentially of polymer of the block group of copolyether ester, block of copolyether amides, polyurethanes and combinations thereof , at least 5% by weight of a Fraction B consisting essentially of a polymer from the group of homopolymers of an alpha olefin, copolymers or terpolymers containing an alpha olefin and one or more other monomers, and a block of copolymers of a vinylarene and a conjugated diene, and at least 0.1% by weight of a Fraction C consisting essentially of a compatibilizer for Fractions A and B.

20. The material of the composite sheet of claim 19, characterized in that said Fraction C of the film consists essentially of homopolymers, copolymers and terpolymers with backbones that are compatible with Fraction B, said backbones are grafted with a monomer having a functional group that is compatible with Fraction A.

21. The material of the composite sheet of claim 20, characterized in that said Fraction C of the film is a polymer with a main chain identical to Fraction B, said main chain is grafted with a monomer selected from the group of alpha- and beta-ethylenically unsaturated carbonic acids and anhydrides, and derivatives thereof.

22. The material of the composite sheet of claim 21, characterized in that the sheet layer comprises, by weight, from 50% to 95% of the Fraction A of the film, from 5% to 40% of the Fraction B of the film, and from 0.1% to 15% of Fraction C of the film.

23. The material of the composite sheet of claim 22, characterized in that Fraction A of the film is a block of ester copolyether, Fraction B of the film is polypropylene, Fraction C of the film is a grafted polymer having a main chain of polypropylene which is grafted with maleic anhydride, and the substrate is a carded fibrous network comprised of at least 75% by weight of polypropylene.

24. A method for making a wet vapor permeable composite sheet material substantially liquid impervious, characterized in that it comprises of a fibrous substrate and a thermoplastic polymer film bonded directly to the fibrous substrate, the fibrous substrate consists of at least 50% fiber by weight of polyolefin polymer, comprising the steps of: mixing the thermoplastic polymer selected from the group of copolyether ester block, copolyether block amides, polyurethanes and combinations thereof; melting and simultaneously mixing the thermoplastic polymer mixture at a temperature higher than the melting temperature of the thermoplastic polymer; extruding the molten and mixed stream of the polymer through a die in the form of a flat film such as a molten film; forcing the molten polymer film into intimate contact with the fibrous substrate while the polymer mixture is quenched to form a composite sheet exhibiting a film thickness of at least 50 microns, a peel strength of at least 0.1 N / cm, a dynamic fluid transmission of less than about 0.75 g / m2 when subjected to an impact energy of approximately 2400 joules / m2, and a wet vapor transmission rate, according to the desiccant method, of at least 1500 g / m224 hr .; Y Collect the material from the composite sheet on a pickup roller.

25. The process of claim 24, characterized in that the step of forcing the molten polymer into intimate contact with the substrate comprises the step of passing the polymer coated substrate between the hot compression rolls that press the polymer film against the substrate while the polymer mixture is cooled.

26. The process of claim 25, characterized in that the temperature at which said thermoplastic film was extruded from the die in the form of a film is in the range of 210 ° to 250 ° C, the compression rolls were maintained at a temperature within the range of 30 ° to 75 ° C, and the thickness of the thermoplastic film in the fibrous substrate after the shut-off step is within the range of 15 to 30 microns.

27. A ventilatable composite sheet material comprises a substrate and a thermoplastic film adhered directly to the substrate, characterized in that said thermoplastic film comprises at least 50% by weight of a Fraction A consisting essentially of polymer of the block group of copolyether ester, block copolyether amide and polyurethanes, at least 5% by weight of a Fraction B consisting essentially of polymer that is compatible with Fraction A, and at least 0.1% by weight of a Fraction C consisting essentially of a compatibilizer of Fractions A and B; Y said substrate comprises at least 50% by weight of a polymer that is incompatible with Fraction A of the film.

28. The material of the composite sheet of claim 27, characterized in that the Fraction B of the film is comprised by at least 50% by weight of at least one homopolymer of an alpha olefin, a copolymer or terpolymer containing an alpha olefin and one or more than other monomers, and a block of a vinylarene and a conjugated diene.

29. The material of the composite sheet of claim 27, characterized in that the substrate is a fibrous non-woven sheet of at least 50% by weight of a polyolefin polymer.

30. The material of the composite sheet of claim 29, characterized in that the substrate is a non-woven sheet made of a fibrous web of at least 50% by weight of a polypropylene.

31. The material of the composite sheet of claim 29, characterized in that the substrate is a non-woven sheet made of a fibrous web of at least 50% by weight of a polyethylene.

32. The material of the composite sheet of claim 28, characterized in that Fraction C of the film consists essentially of copolymer homopolymers and terpolymers with backbones which are compatible with Fraction B, said main chain is grafted with a monomer having a functional group which is compatible with Fraction A.

33. The material of the composite sheet of claim 32, characterized in that Fraction C is a polymer with the main chain identical to Fraction B, said main chain is grafted with a monomer selected from the group of alpha- and beta-ethylene-carbonic acids and anhydrides. unsaturated, and derivatives thereof.

34. The material of the composite sheet of claim 27, characterized in that Fraction A of the film is a block of ester copolyether, Fraction B of the film is polypropylene, Fraction C of the film is a polymer having a backbone of polypropylene which is grafted with maleic anhydride, and the substrate is a nonwoven web bonded sheet made of a fibrous web comprised of at least 50% by weight of a polypropylene.

35. The material of the composite sheet of claim 34, characterized in that the thermoplastic film comprises, by weight 50% to 95% of Fraction A of the film, from 5% to 50% of Fraction B of the film, and 0.1 % to 15% of Fraction C of the film.

36. The material of the composite sheet of claim 35, characterized in that the coating thickness of the thermoplastic film is in the range of 5 to 50 microns, and the sheet material has a wet steam transmission rate of at least 200 g / m224 hr (by the method ASTM E96-B), and a peel strength per unit thickness of the thermoplastic film of the sheet material at least 0.003 N / cm-micron.

37. A method for making a ventilatable composite sheet material comprising a substrate and a thermoplastic film adhered directly to the substrate, characterized in that it comprises the steps of: mixing Fractions A, B and C of the polymer where fraction A comprises at least 50% by weight of one of a block of copolyether ester, a block of copolyether amide and a polyurethane, Fraction B is comprised of less than 50% by weight of one of a homopolymer, copolymer and thermoplastic terpolymer that is incompatible with Fraction A, and Fraction C is comprised of less than 30% by weight of a compatibilizer of Fractions A and B; melt and simultaneously mix the mixture of Fractions A, B and C; extruding the melted and mixed stream of Fractions A, B and C of the polymer through a die in the form of a flat film and extruding the film of the polymer mixture directly onto a moving substrate; forcing the molten polymer into intimate contact with the fibrous substrate while the polymer mixture is quenched to form a sheet material; Y Collect the laminar material on a collection roller.

38. The process of claim 37, characterized in that the step of forcing the molten polymer into intimate contact with the substrate comprises the step of passing the polymer coated substrate between the compression rollers that press the polymer film against the substrate while the polymer mixture is cooled to form a sheet material.

39. The process of claim 37, characterized in that the step of forcing the molten polymer into intimate contact with the substrate comprises the step of passing the polymer coated substrate into a vacuum inlet that pulls the polymer against the substrate while cooling the polymer mixture to form a sheet material.

40. The process of claim 37, characterized in that Fraction B is comprised of at least 50% by weight of a homopolymer of an alpha olefin, a copolymer or a terpolymer containing an alpha olefin and one or more other monomers, and a block of a vinylarene copolymer and a conjugated diene, and wherein the substrate is a fibrous nonwoven sheet comprised of at least 50% by weight of a polyolefin polymer.

41. The process of claim 40, characterized in that Fraction C with a backbone compatible with Fraction B which is grafted with a monomer selected from the group of alpha- and beta-ethylene-unsaturated carbonic acids and anhydrides, and derivatives thereof, and where the step of dry blending Fractions A, B and C comprises mixing, by weight, from 50% to 95% of Fraction A, from 5% to 50% of Fraction B, and from 0.1% to 15% of the Fraction C.

42. The material of the composite sheet of claim 41, characterized in that the film thickness of the polymer blend coated on the moving substrate is in the range of 5 to 50 microns, the peel strength per unit thickness of the film of the sheet material at least 0.03 N / cm-micron, and the wet steam transmission rate of the sheet material is at least 200 g / m224 hr (by the ASTM E96-B method).

43. An absorbent article comprises: (a) a top sheet; (b) a backing sheet; and (c) an absorbent center positioned between said top sheet and said backsheet, characterized in that at least a portion of said backsheet comprises a liquid impervious composite sheet material, permeable to wet steam having at least one fibrous layer and at least one laminar layer directly and intimately bonded to said fibrous layer in the absence of any additional adhesive, said composite laminar material exhibits an MVTR of at least 1000 g / m24hr and a peel strength between said laminar layer and said fibrous layer at least of 0.1 N / cm.

44. The absorbent article of claim 43, characterized in that said composite laminar material comprises at least two laminar layers.

45. The absorbent article of claim 43, characterized in that said composite sheet material exhibits a moisture impact value of less than about 1.0 g / m2 to 2400 j / m2.

46. The absorbent article of claim 43, characterized in that said composite sheet material exhibits a tensile strength in at least two mutually orthogonal directions in the plane of said composite material of at least about 1.0 N / cm.

47. The absorbent article of claim 44, characterized in that said sheet layer comprises at least two layers of different composition.

48. The absorbent article of claim 43, characterized in that said composite sheet material is oriented such that said sheet layer is oriented toward said absorbent center.

49. The absorbent article of claim 47, characterized in that one of said laminar layers comprises a substantially hydrophilic elastomer film and one of said laminar layers comprises a substantially hydrophobic elastomer film.

50. The absorbent article of claim 49, characterized in that said substantially hydrophilic elastomer film is placed between said substantially hydrophobic elastomer film and said fibrous layer.

51. The absorbent article of claim 50, characterized in that said sheet layer comprises a third sheet layer comprising a substantially hydrophobic elastomer film placed between said substantially hydrophilic elastomer film and said fibrous layer.

52. The absorbent article of claim 43, characterized in that said sheet layer comprises at least 50% by weight of a polymer selected from the group of the block copolyether esters, the block copolyether amides, polyurethanes and combinations thereof.

53. The absorbent article of claim 43, characterized in that said sheet layer comprises at least 50% by weight of Fraction A consisting essentially of the block copolyether ester polymer, the block copolyether amides, polyurethanes, at least 5% by weight of Fraction B consists essentially of a polymer from the group of homopolymers of an alpha olefin, a copolymer or a terpolymer containing an alpha olefin and one or more other monomers, and a block of copolymer of a vinylarene and a conjugated diene, and less 0.1% by weight of a Fraction C consists essentially of a compatibilizer of Fractions A and B.

54. The absorbent article of claim 53, characterized in that said fibrous layer comprises at least 50% by weight of a polymer that is incompatible with Fraction A.

55. The absorbent article of claim 53, characterized in that said fibrous layer comprises a fibrous nonwoven sheet comprised of at least 50% by weight of a polyolefin polymer.

56. The absorbent article of claim 43, characterized in that said sheet layer comprises a polyolefin polyether.

57. The absorbent article of claim 43, characterized in that said absorbent article comprises a disposable diaper.

58. The absorbent article of claim 43, characterized in that said composite sheet further includes an additional layer of various construction and composition of said sheet layer and said fibrous layer.

59. The absorbent article of claim 58, characterized in that said additional layer comprises a microporous film.

60. The absorbent article of claim 43, characterized in that said absorbent article further includes at least a peripheral portion extending laterally outwardly from said absorbent center, and wherein said peripheral portion comprises a fluid impermeable, moisture vapor permeable laminate material that has at least one fibrous layer and at least one laminar layer directly and intimately bonded to said fibrous layer in the absence of any additional adhesive, said composite laminar material exhibits an MVTR of at least about 1000 g / m2 / 24 hr., and a strength to the release between said laminar layer and said fibrous layer of at least about 1.0 N / cm.

61. The absorbent article of claim 60, characterized in that said peripheral portion comprises a fold in the leg area.

62. The absorbent article of claim 60, characterized in that said composite sheet material comprises at least two fibrous layers, each of said fibrous layers being on opposite sides of said sheet layer.

63. The absorbent article of claim 60, characterized in that at least one of said backing sheet and said peripheral portion has been subjected to mechanical post-forming processing.

64. The absorbent article of claim 43, characterized in that said sheet layer of said composite sheet has a thickness between about 10 microns and about 25 microns, and the basis weight of said fibrous substrate is between about 13.5 and about 40 g / m2.

65. An absorbent article comprising a backsheet, characterized in that at least a portion of said backing sheet comprises a wet vapor-permeable composite sheet material, impervious to liquid having a fibrous substrate and a thermoplastic sheet layer permeable to wet steam, said substrate fiber is comprised of synthetic fiber, said synthetic fibers are comprised of at least 50% by weight of polyolefin polymer, said substrate having opposite the first and second planar surfaces, said thermoplastic sheet layer permeable to wet steam is directly melt-bonded to the first On the side of said substrate, said composite sheet exhibits a peel strength of at least 0.1 N / cm, a dynamic fluid transmission of less than 1 g / m2 when subjected to an impact energy of approximately 2400 Joules / m2, and having a wet steam transmission rate, according to the desiccant method, of less approximately 1500 g / m2 / 24 hr.

66. The absorbent article of claim 65, characterized in that said absorbent article further comprises a topsheet associated with said backsheet and an absorbent center positioned between said top sheet and said backsheet.

67. The absorbent article of claim 65, characterized in that said sheet layer comprises at least 50% by weight of a polymer selected from the group of the block copolyether esters, the block copolyether amides, polyurethanes and combinations thereof.

68. An absorbent article characterized in that it comprises a backing sheet, at least a portion of said backing sheet comprising a substrate and a thermoplastic film directly adhered to said substrate, said thermoplastic film comprising at least 50% by weight of Fraction A which consists essentially of the copolyether ester block polymer, the block copolyether amides, polyurethanes, at least 5% by weight of Fraction B consists essentially of at least 0.1% by weight of a Fraction C consists essentially of a compatibilizer of the Fractions A and B, and said substrate comprises at least 50% by weight of a polymer that is incompatible with Fraction A of the film.

69. The absorbent article of claim 68, characterized in that said absorbent article further comprises a topsheet associated with said backsheet and an absorbent center positioned between said top sheet and said backsheet.

70. The absorbent article of claim 68, characterized in that Fraction B of the film is comprised of at least 50% by weight of at least one of a homopolymer of an alpha olefin, a copolymer or terpolymer containing an alpha olefin and one or more of other monomers, and a block of the copolymer of a vinylarene and a conjugated diene.

71. The absorbent article of claim 70, characterized in that said substrate is a fibrous nonwoven sheet comprised of at least 50% by weight of a polyolefin polymer.

72. An absorbent article comprising a backsheet, characterized in that at least a portion of said backsheet comprises a wet vapor permeable, liquid impermeable composite laminar material having a microporous laminar substrate and a wet vapor permeable thermoplastic sheet layer comprised of a polymer selected from the block group of the copolyether ester, copolyether amides, polyurethanes, and combinations thereof, said microporous sheet substrate is comprised of at least 50% by weight polyolefin polymer, said microporous sheet substrate has opposite the first and second surfaces For example, said planar sheets, said wet vapor-permeable thermoplastic sheet layer is directly melt-bonded to the first side of said substrate, said composite sheet exhibits a peel strength of at least 0.1 N / cm, a dynamic fluid transmission of less than 1 g / m2 when was subjected to an approximate impact energy at 2400 Joules / m2, and having a wet steam transmission rate, according to the desiccant method, of at least about 1500 g / m2 / 24 hr.

73. The absorbent article of claim 72, characterized in that said absorbent further comprises a topsheet associated with said backsheet and an absorbent center positioned between said top sheet and said backsheet. SUMMARY OF THE INVENTION A ventilatable composite sheet material, a method for making such a sheet material, and an absorbent article using the sheet material that is provided. The composite sheet material is comprised of a thermoplastic film directly adhered to a fibrous substrate. The thermoplastic film comprises at least 50% by weight of a polymer material of the block group of the copolyether ester, copolyether amides, polyurethanes. The substrate comprises a fibrous network of at least 50% by weight of synthetic polymer polyolefin fibers. The composite sheet exhibits a peel strength of at least 0.1 N / cm, a dynamic fluid transmission less than 0.75 g / m2 when subjected to an impact energy of approximately 2400 Joules / m2, and having a transmission velocity of wet steam, according to the desiccant method, at least about 1500 g / m2 / 24 hr. The absorbent article comprises: (a) a top sheet; (b) a backing sheet; and (c) an absorbent center positioned between the topsheet and the backsheet; wherein the backsheet comprises the non-porous composite laminate material, impervious to the wet vapor permeable fluid described above. The composite sheet material is oriented such that the sheet layer of the composite sheet material faces the absorbent center. The absorbent article may comprise a disposable diaper.