MXPA00005740A - The use of a breathable absorbent article construction to provide a clean and dry topsheet - Google Patents

Abstract

The present invention relates to absorbent articles such as sanitary napkins and the use of breathable backsheet constructions therein to provide improved topsheet performance. In particular, the present invention relates to a moisture vapour permeable, liquid impermeable backsheet and its use for the provision of a dry wearer facing surface, preferably a topsheet of an absorbent article.

Description

THE USE OF A BREATHABLE ABSORBENT ARTICLE CONSTRUCTION TO PROVIDE A CLEAN AND DRY TOP SHEET FIELD OF THE INVENTION The present invention relates to absorbent articles and in particular sanitary napkins and the use of the breathable backsheet constructions therein to provide improved performance of the topsheet.

BACKGROUND OF THE INVENTION Absorbent articles such as sanitary pads, pads, incontinence products and perspiration pads are well known in the art. Typically, these articles comprise a surface that gives the user and a surface that gives the garment. The surface that it gives to the user receives the discharges coming from the body such as urine, faeces, vaginal discharges and similar, which will be absorbed and stored by the article. In order for the article to absorb the discharges, the surface that it gives to the user of the articles needs to be permeable to the liquid. This surface that gives the user is known as the top sheet. The top sheets are also known in the art and are typically selected from nonwoven, woven, or apertured film materials. Woven and non-woven materials are desirable as long as they provide a fabric-like appearance to the top sheet and a relatively soft and comfortable appearance for the wearer. However, the problem with these top sheets is that they also have some capacity to absorb. The upper sheets in this way become saturated quickly and feel moist for the user of the product. In addition, these woven or non-woven upper sheets can also quickly develop an appearance in use, not clean and non-sanitary. Attempts to remedy these problems however, by the use of surface treatments for example, have not proven to be particularly satisfactory. The alternative proposed upper sheets are films formed with openings having tunnel openings which are designed to promote the passage of the liquid discharged through the topsheet and into the absorbent core. These types of top sheets are preferred because the problem of rewetting is usually avoided. However, a particular problem associated with these top sheets is that the top sheet is very sticky to the user of the product and may in some circumstances adhere to the user's skin during use, which is highly uncomfortable. Moreover, due to the nature of the polymer of the upper sheets, the upper sheet can also become hotter during use attributing more to the awkward impression experienced by the user during use. Another common problem of the upper sheets described above is related to the speed at which the upper sheet is able to allow liquids to pass through it under normal conditions of use. This speed is typically dependent on the total amount of the open area of the openings, and the individual shape and size of the openings in the upper sheet. The exceptionally large openings increase the speed of the liquid passage but have problems related to the manufacture of these upper sheets, particularly as regards the stability of the material of the upper sheet itself. Additionally, large openings can also promote a reflux of absorbed liquid known as rewet. This is particularly undesirable since the user of the product experiences a wet sensation during the total time of product use and promotes unnecessary product replacement changes. On the other hand small openings can not provide the speed of the passage of the required liquid through the upper sheet. The problem of the speed of liquid passage through the upper sheets is further exacerbated by high surface tension liquids, of high viscosity, or liquids having a high solids content such as coagulated blood which may cause complete blockage of the openings. In addition to the actual speed of the discharge of the liquid through the upper sheet, changes in the speed of the liquid discharged from the user's body and the variation in the viscosity of the liquid discharged from a liquid must also be taken into account. person to another person and over the period of time of a woman's period. Consequently, the upper sheet must be able to cope with the considerable fluctuations in the speed of the discharge of liquid from the user in order to avoid the collection of liquid on the upper sheet and cause the wet and uncomfortable feeling for the user. Yet another particularly acute problem for the upper sheets of a type of film formed with openings, is that due to the presence of the integral openings, skin irritation such as abrasion and skin sensitivity can be caused by further increasing the discomfort experienced by the user. Therefore, there is a need here to improve the top sheet materials currently used so that they appear soft and comfortable for the user while not compromising their ability to promote the passage of the liquid without rewetting and thus maintain a dry surface. It has now surprisingly been found that the problems associated with the top sheets can be treated by the incorporation and use of breathable backsheet constructions in the absorbent article.

In particular, it has surprisingly been found that the use of breathable backsheet constructions within the absorbent articles provides an upper sheet with clean appearance for the user, due to the absence of liquid waste and does not tend to adhere to the wearer's skin, besides being dry. Therefore, the user of the product feels clean and dry and has minimal knowledge that the product is used.

BRIEF DESCRIPTION OF THE INVENTION The present invention relates to the use of a breathable absorbent article having in particular a water vapor permeable sheet, impervious to liquid. Said article comprises a surface that gives the user and a surface that gives the garment and the back sheet comprises the surface that gives the garment. Accordingly, the present invention relates to the use of the backsheet to provide a surface that gives the user dry. Preferably, said surface that gives the user comprises the top sheet of said article.

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to disposable absorbent articles such as sanitary napkins, pantiliners, incontinence products, perspiration pads and baby diapers. According to the present invention, these products comprise a surface that gives the user and a surface that gives the garment. Typically, these products comprise a liquid pervious topsheet providing the user-facing surface, a backsheet providing the garment-facing surface and an intermediate absorbent core to the topsheet and the backsheet. The present invention relates to these articles, which comprise a wet vapor permeable, liquid impermeable backsheet, more commonly referred to as a breathable backsheet. The absorbent articles may also comprise any of the components or features common in the art, in particular the side wrapping elements, the side flap components, or wings, as well as any type of extension capacity or elastic characteristic that may be included within. of absorbent articles. For example, a typical sanitary napkin or pantyhose comprises an adhesive area on the garment facing surface of the backsheet providing the panty fastening adhesive, which is covered by a removable paper, wrapper or the like beforehand. of the use of the article. The absorbent article for absorbing the liquid is described below with reference to a sanitary napkin or pantyhose. However, products such as adult or baby diapers, incontinence products or transpiration pads can benefit similarly from the present invention.

BACK SHEET The absorbent article according to the present invention comprises as an essential characteristic a breathable backsheet. The backsheet mainly prevents the exudates absorbed and contained within the absorbent structure from wetting the articles that are in contact with the absorbent product such as underpants, pants, pajamas and undergarments thus acting as a barrier for the transport of the fluid. The backsheet typically extends throughout the entire absorbent structure and can extend into and form part of, or all of the side flaps, the side wrapping elements or the wings. However, in addition to acting as a barrier to the liquid, the breathable backsheet of the present invention allows the transfer of at least the wet vapor, preferably both the vapor and the air therethrough and thus allows circulation of gases in and out of the back sheet. It has now been more surprisingly identified that the use of a breathable back also provides desirable benefits to the backsheet of the article. In particular, the use of a breathable back sheet provides a surface that gives the body clean and dry, preferably the top sheet, such that the surface feels dry to the touch and the user's skin of the article does not feel wet or damp and so The user experiences minimal discomfort during use. In accordance with the present invention, the breathable backsheets suitable for providing the benefits as described hereinbefore can be any breathable backsheet known in the art comprising at least one wet vapor permeable layer. Suitable wet vapor permeable layers include two-dimensional layers, micro and macro porous flat films; the macroscopically expanded films; films with openings formed; the monolithic films and the nonwoven layers. In accordance with the present invention, the openings in said layer can be of any configuration. The openings are preferably uniformly distributed across the entire surface of the layer, however, the layers having only certain regions of the surface having openings are also contemplated. The suitable two-dimensional porous flat layers of the backsheet can be made of any material known in the art, but are preferably manufactured from commonly available polymeric materials. Suitable materials are, for example, Goretex (MR) or Sympatex (MR) type materials well known in the art for their application in so-called breathable garments. Other suitable materials include XMP-1001 from Minnesota Mining and Manufacturing Company, St. Paul, Minnesota, USA and Exxaire XBF-101W, supplied by Exxon Chemical Company. As used herein, the term "flat two-dimensional layer" refers to the layers having a depth of less than 1 mm, preferably less than .05 mm, wherein the openings have a uniform average diameter along their length and which does not protrudes from the plane of the layer. Materials with openings for use as a backsheet in the present invention can be produced using any of the methods known in the art such as described in European Patent EPO 293 482 and references therein. In addition, the dimensions of the openings produced by this method can be increased by applying a force through the plane of the backsheet layer (i.e., stretching the layer). Films formed with suitable apertures include films having discrete apertures that extend beyond the horizontal plane of the garment facing surface of the layer towards the core thereby forming protuberances. The protuberances have a hole located at their terminal end. Preferably, said protuberances are of a funnel shape, similar to those described in U.S. Patent No. 3,929,135. The openings located within the plane and the holes located at the terminal end of the protuberance itself may be circular or non-circular as long as the dimension or cross-sectional area of the hole at the end of the protuberances is less than the dimension or area in the protuberances. cross section of the opening located within the surface that gives the clothing of the layer.

Preferably, the films formed with openings are unidirectional 9 1 such that they have at least substantially, if not completely unidirectional fluid transport to the core. Macroscopically expanded films suitable for use herein include the films as described in, for example, U.S. Patent No. 4,637,819 and U.S. Patent No. 4,591,523. Suitable monolithic films include Hytrel ™, available from DuPont Corporation, USA, and other such materials as described in 93 Congress Session 7A "Added Value to Nonwovens", JC Cardinal and Y. Trouilhet, DuPont de Nemours International SA, Switzerland such as Pebax ™, available by Elf Atochem (France) and Estañe ™ available from BF Goodrich (Belgium). The preferred respirable backsheets for use herein are those which have a high wet vapor exchange, most preferably both a high wet vapor exchange and high air exchange. Particularly preferred backsheets for the present invention comprise at least two layers comprising at least one layer selected from the above, such as a microporous layer or a film formed with openings and an additional layer that can also be selected from the sheets previously listed. The highly preferred respirable backsheet component comprises a microporous film and a film formed with openings, or a microporous film and a hydrophobic fibrous layer; or a film formed with openings and a hydrophobic fibrous layer. Preferably, the hydrophobic fibrous layers are hydrophobic nonwoven materials.

THE TOP SHEET In accordance with the present invention, it has been found that any of the upper sheets typically used in the absorbent articles can obtain a dry benefit from the use of the breathable backsheet. The upper sheet is docile, soft feeling, and non-irritating to the user's skin. The upper sheet can also have elastic characteristics that allow it to be stretched in one or two directions, in parts of the upper sheet or in its entire extension. In addition, the top sheet is permeable to liquids, allowing fluids (eg, menses and / or urine) to easily penetrate through their thickness. A suitable top sheet can be manufactured from a wide range of materials such as woven and nonwoven materials; polymeric materials such as thermoplastic films formed with openings, plastic films with openings, and hydroformed thermoplastic films; and thermoplastic liners and combinations thereof. Suitable woven and nonwoven materials may be composed of natural fibers (eg, wood or cotton fibers), synthetic fibers (e.g., polymer fibers such as polyester, polypropylene or polyethylene fibers) or a combination thereof. natural and synthetic fibers or two / multicomponent fibers and are preferably hydrophobic. The preferred top sheets for use in the present invention are selected from the upper non-woven top sheets and upper sheets of apertured film. Films formed with openings are especially preferred for the upper sheets because they are permeable to body exudates and still non-absorbent and have a reduced tendency to allow fluids to pass back through and re-wet the skin of the body. user. In this way, the surface of the formed film that is in contact with the body remains dry, thereby reducing the staining 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; United States Patent No. 4,324,246; U.S. Patent No. 4,463,045; and in U.S. Patent No. 5,006,394. Top sheets of film formed with particularly preferred micro apertures are disclosed in U.S. Patent No. 4,609,518 and U.S. Patent No. 4,629,643. A preferred top sheet for the present invention comprises the formed film described in one or more of the above patents and sanitary napkins are marketed by The Procter & Gamble Company of Cincinnati, Ohio as "DRI-WEAVE". The upper sheets that do not have a homogeneous distribution of the liquid passages but only a part of the upper sheet comprising passages of liquid are also contemplated by the present invention. Typically, these upper sheets would have the liquid passages oriented such that they result in a centrally permeable upper sheet and peripherally impervious to liquids. The surface that gives the body of the formed film top sheet can be hydrophilic to help transfer the liquid more rapidly through the top sheet than if the body surface were not hydrophilic. In a preferred embodiment, surfactant is incorporated into the polymeric materials of the formed film topsheet as described in PCT publication WO 93/09741. Alternatively, the body surface of the topsheet can be made hydrophilic by treating it with a surfactant such as described in U.S. Patent No. 4,950,254. Another alternative is the so-called hybrid upper sheets, which incorporate fibrous structures and film-like structures. Particularly useful embodiments of these hybrid top sheets are disclosed in PCT disclosures WO 93/09744; WO 93/11725 or WO 93/1 1726 and in U.S. Patent No. 4,780,352. When reference is made to the topsheet, a multilayer structure or a layer structure is contemplated. A hybrid top sheet mentioned above is a multi-layered design but other sheets of multiple top layers such as the primary and secondary top sheet designs are also considered. The topsheet typically extends through the entire absorbent structure and out of the coextensive area with the absorbent structure. The top sheet can extend and be part of all or of the side flaps, the side wrapping elements or the preferred wings.

THE ABSORBENT NUCLEUS In accordance with the present invention the absorbent cores suitable for use herein may be selected from any of the absorbent cores or core systems known in the art. As used herein, the term "absorbent core" refers to any material or layers of multiple material whose primary function is to absorb, store, and distribute the fluid. In accordance with the present invention, the absorbent core can include the following components: (a) a primary optional fluid distribution layer preferably together with a secondary optional fluid distribution layer; (b) a fluid storage layer; (c) an optional fibrous layer ("dedusting") beneath the storage layer; and (d) other optional components.

Primary / secondary layer of fluid distribution An optional component of the absorbent core according to the present invention is a primary fluid distribution layer and a secondary fluid distribution layer. The primary distribution layer is typically below the top sheet and is in fluid communication therewith. The top sheet transfers the acquired fluid to this primary distribution layer for final distribution to the storage layer. This transfer of fluid through the primary distribution layer occurs not only within the thickness, but also along the length and width of the absorbent product. The also optional but preferred secondary distribution layer is typically below the primary distribution layer and is in fluid communication therewith. The purpose of this secondary distribution layer is to easily acquire the fluid from the primary distribution layer and transfer it rapidly to the underlying storage layer. This helps the fluid capacity of the underlying storage layer to be fully utilized. The fluid distribution layers can be composed of any typical material for these distribution layers. b Fluid storage layer Placed in fluid communication with, and typically underlying the primary or secondary distribution layers, is a fluid storage layer. The fluid storage layer may comprise any common absorbent material or combinations thereof. This preferably comprises gelling absorbent materials commonly referred to as "hydrogel", "superabsorbent", "hydrocolloid" materials in combination with suitable carriers.

The gelling absorbent materials are capable of absorbing large amounts of aqueous body fluids, and are capable of retaining these absorbed fluids under moderate pressures. The gelling absorbent materials may be dispersed homogeneously or non-homogeneously in a suitable carrier. Suitable carriers, provided they are absorbent as such, can also be used alone. The gelling absorbent materials suitable for use herein will most often comprise a substantially water-insoluble, slightly crosslinked, partially neutralized polymeric gelling material. This material forms a hydrogel upon contact with water. These polymeric materials can be prepared from polymerizable, unsaturated, acid-containing monomers, which are well known in the art. Suitable carriers include materials that are conventionally used in absorbent structures such as natural, modified or synthetic fibers, particularly modified or unmodified cellulose fibers, in the form of fluff, and / or tissue. Suitable carriers can be used in conjunction with the gelling absorbent material, however, they can also be used alone or in combinations. Very preferred are tissue or laminate tissue within the context of sanitary napkins and pantyhose. One embodiment of the absorbent structure made in accordance with the present invention comprises a double layer tissue laminate formed by bending the tissue on itself. These layers can be bonded together, for example, by adhesive or by mechanical internal locking or by hydrogen strips. The gelling absorbent materials or other optional materials may be comprised between the layers.

Modified cellulose fibers such as hardened cellulose fibers can also be used. Synthetic fibers can also be used and include those made from cellulose acetate, polyvinyl fluoride, polyvinylidene chloride, acrylics (such as orlon), polyvinyl acetate, non-soluble polyvinyl alcohol, polyethylene, polypropylene, polyamides (such as nylon), polyesters, two-component fibers, three-component fibers, mixtures thereof and the like. Preferably, the surfaces of the fibers are hydrophilic or are treated to be hydrophilic. The storage layer may also include filling materials such as perlite, diatomaceous earth, vermiculite, etc., to improve liquid retention. If the gelling absorbent material is dispersed in an inhomogeneous manner in a carrier, the storage layer can, however, be locally homogeneous, that is, have a distribution gradient in one or more directions within the dimensions of the storage layer. The inhomogeneous distribution can also refer to the laminates of the carriers that partially or completely enclose the gelling absorbent materials.

Optional fibrous layer ("dedusting") An optional component for inclusion within the absorbent core according to the present invention is a fibrous layer adjacent to, and typically underlying the storage layer. This underlying fibrous layer is typically referred to as a "dedusting" layer since it provides a substrate on which the absorbent gelling material is deposited in the storage layer during the manufacture of the absorbent core. Indeed, in those cases where the gelling absorbent material is in the form of macro structures such as fibers, sheets or strips, this fibrous "dedusting" layer need not be included. However, this "dedusting" layer provides some of the additional fluid handling capabilities such as the rapid capillary action of the fluid along the length of the pad. d Other optional components of the absorbent structure.

The absorbent core according to the present invention may include other optional components normally present in the absorbent webs. For example, a reinforcing fabric may be placed within the respective layers, or between the respective layers, of the absorbent core. These reinforcement canvases should be of such configuration so as not to form interfacial barriers for fluid transfer. Given the structural integrity that normally occurs as a result of thermal bonding, reinforcing canvases are not normally required for thermally bonded absorbent structures. Another component that can be included within the absorbent core according to the present invention and is preferably provided close to or as part of the primary or secondary fluid distribution layer are the odor control agents. A preferred sanitary napkin or pantyhose made in accordance with the present invention has a pair of side wrapping elements or "undergarment cover components". These elements or components provide protection for the wearer's panties to reduce lateral spotting (i.e., spotting of the crotch edges of the pantyhose) and are typically smaller than conventional fins or wings. The function of the side wrapping elements, if they are integral with the article or are attached to the article after being formed separately, is further improved by making them extendible in one or both directions parallel to the longitudinal axis and / or lateral axis. The extension capacity can be provided through all or only part of the side wrapping elements and can be achieved by folding or rolling with ring those parts that are to be made extensible. According to the present invention, the top sheet components can be joined together, the backsheet and the absorbent core to provide the absorbent article. Typically, at least two, preferably all of the components of the article are joined to form the article. Each of said components of the absorbent article comprises at least one layer and has a surface that gives the wearer and a surface that gives the garment. Typically, the adjacent garment facing surfaces form a common interface with the surface that gives the wearer an adjacent component or layer. The elements or layers are joined together through their common interface. In this way, the upper sheet is attached to the absorbent core, and the absorbent core is attached to the backsheet. In addition, the topsheet may be attached directly or indirectly to the backsheet at the periphery of the absorbent article. In addition, particularly in the sanitary napkin, the panty-protector and incontinence product applications, the garment facing surface of the backsheet also provides the surface to which the absorbent article is removably attached to the garment. of the user of the product. Before use, this surface is typically provided with a protective cover. Any means known in the art can be used to join the components of the absorbent article and provide the garment fastener, such as by using a continuous adhesive layer, a patterned adhesive layer, such as spirals, or dots, or using joints with heat, pressure joints, mechanical joints and the like.

Claims (8)

1. The use of a wet vapor permeable, liquid impervious backsheet in an absorbent article, said article further comprising a surface that gives the wearer and a surface that gives the garment, said surface that gives the garment being provided by said backsheet in order to provide a surface that gives the user dry.

2. The use according to claim 1, wherein said absorbent article further comprises a top sheet and an absorbent core, the core being located between the top sheet and the back sheet and wherein the top sheet provides the surface that gives the user.

3. The use according to claim 1 of the backsheet, wherein the backsheet comprises at least one layer selected from films formed with openings, two-dimensional flat films with openings or non-woven materials.

4. The use according to claim 3, wherein the backsheet comprises at least two layers, and wherein both of the layers are independently selected from polymeric films formed with openings and flat two-dimensional films with openings.

The use according to claim 3, wherein the backsheet comprises at least two layers, a first layer comprising a layer with openings and a second layer comprising a fibrous layer.

The use according to claim 2, wherein the topsheet is a non-absorbent topsheet, preferably a hydrophobic nonwoven material or an apertured polymeric film.

7. The use according to claim 2, wherein the topsheet is a polymeric film formed with openings.

8. The use according to any of the preceding claims, in said absorbent article is a sanitary napkin or a pantyhose.