MXPA00006240A - Absorbent articles having construction adhesives applied at differing adhesive zones - Google Patents

Abstract

The present invention relates to breathable disposable absorbent articles having a breathable backsheet and having an improved adhesive application configuration in order to minimize the affect of the presence of the adhesive on the breathability of the article. The adhesive configuration comprises an adhesive application comprising at least two zones of adhesive which are applied at differing basis weight.

Description

ABSORBENT ARTICLES THAT HAVE MOUNTING ADHESIVES APPLIED IN DIFFERENT ADHESIVE ZONES FIELD OF THE INVENTION The present invention relates to disposable absorbent articles such as sanitary napkins, pantiliners, incontinence devices and diapers, particularly those having a breathable backsheet. In particular, the invention relates to adhering two adjacent components of the article to one another with an adhesive to provide at least two different base weight areas of adhesive. The use of the adhesive zones allows the amount of adhesive used to be reduced while maintaining the required degree of fixation. In addition, when used in combination with the breathable backsheets, the adhesive zones of the present invention do not significantly affect the breathability of the backsheet.

BACKGROUND OF THE INVENTION Absorbent articles such as sanitary napkins, pantiliners, catamenial products, incontinence inserts and diapers for adults or babies are commonly provided with an adhesive on their surface that gives the garment to fix them during its period of use to a garment. dress the user. In particular, sanitary napkins and pantiliners are commonly provided with a thermal melt adhesive, pressure sensitive, which provides fixation of the product to the user's undergarment and thus improves the fit and comfort of the product for users called adhesive. of panties. These adhesives are typically covered with a release paper before use. More generally, the absorbent articles are provided with adhesive areas in order to combine the components that make up part or all of the absorbent article. In particular, the multi-layered structures forming the topsheet, the core or the backsheet are often combined by adhesives called assembly adhesives. In addition, the combination of the top sheet, the core and the back sheet itself can also be achieved by the adhesives. Typically these products are made by high speed machinery. The machinery includes the equipment that adds the adhesive in a very fast and efficient way, ensuring the consistency of the absorbent products over large quantities of them. There are a number of methods of application of the adhesive using said machinery such as slot coating, spraying the adhesive onto a web of continuously transported material, using a screen or mesh printing or making one of the materials used in the production of the materials. absorbent articles adhesive. An alternative method that allows the provision of the adhesive to a substrate which is not limited to any particular form, in roll printing. Using these methods attempts have been made to optimize the distribution of the adhesive. Obviously, this is not always cost effective for the manufacturers of these disposable products to apply the adhesive homogeneously on the total surface to which the other surface is to be fixed. However, reducing the amount of the adhesive will obviously detrimentally affect the performance or performance of the adhesive. In particular problems that have arisen as a result of the reduction of the amount of the adhesive on the surface that gives the garment of the article, include the problems such as the rolling of the product in the periphery which often results in contact of the adhesive with the genital organs of the user or the piling of the product. The technique teaches different patterns of application of adhesive which try to optimize the performance of the adhesive although avoiding the aforementioned problems. For example, the British patent GB 2 081 100 discloses a sanitary napkin comprising a deviator impervious to fluid and having sharp edges and a pressure-sensitive adhesive strip corresponding to these edges. GB 2 081 101 relates to a sanitary napkin having a fluid impervious diverter with a garment attachment adhesive arranged in a separate uniformly distributed pattern which is inserted from the periphery of the towel and covers 50% to 90% of the surface. European patent EP 025 611 describes a self-adhesive sanitary article having a number of small strips of pressure-sensitive adhesive, in the longitudinal and transverse direction extending near the edge or edge of the article. European Patent EP 548 188 is related to a shape and an adhesive fastening means for an absorbent article. The absorbent article having a caliper of less than 5 mm and a fastening means comprising a zone of adhesive having outer edges and ends spaced at a distance of 6 mm plus or minus 3 mm from the periphery. European patent EP 607 986 relates to fastening systems for tight fitting of absorbent products. The absorbent articles having the adhesive fixing means for securing the article to an undergarment comprising adhesive areas in the anterior and posterior regions of the product such that the central portion is free of adhesive.

However, a disadvantage of all of these proposed adhesive configurations is that the surface applied with the adhesive essentially comprises areas comprising adhesive and areas that are free of the adhesive. These configurations in principle always result in areas of the surface that are fixed to the adjacent surface and areas of the surface that remain disjointed and are therefore free to move and separate. Typically, the optimal distribution of the adhesive is considered to reside in an application of the adhesive towards the edges and periphery of the product, where the forces of shear that the adhesive must resist are larger, and also where the adhesive bond tends to fray, while which provides adhesive-free areas towards the center of the product. However, although said distribution of adhesive promotes the secure fixation of the surface this promotes the accumulation of the product in the center. Moreover, the presence of the adhesive on the periphery of the product also creates problems in terms of the ease of handling of the products by the consumer. In particular, the presence of the adhesive on the periphery of the product results in the consumer having to be in contact with the adhesive area while removing the release paper and placing the product on the undergarment and in the same manner while removing the adhesive. product after use. This is highly undesirable since the consumer may have residues of the adhesive transferred to his hand. Consequently, there still exists a need to provide an application distribution of the adhesive that minimizes the amount of adhesive required while ensuring surface addition and preferably maintains the ease of application and removal of the garment product. Another disadvantage related to the adhesive configurations currently used is the context of so-called breathable products. In order to improve the comfort of the absorbent products during use, these products are provided with wet steam permeable backsheets, referred to otherwise as breathable backsheets. These breathable backsheets allow the transport of the moist vapor and preferably the moist vapor and air, while preferably avoiding the transport of the liquid. The commonly used breathable backsheets comprise at least one layer of a microporous layer and a unidirectionally formed film. However, the application of the assembly adhesives and in particular the fastening adhesives of the panty on the absorbent products having a breathable backsheet has a detrimental effect on the rate of transfer of the wet vapor from the breathable backsheet. As a result, while the product can still be considered to be respirable as a consequence of the presence of the breathable backsheet, the actual breathability level or wet steam transport regime is considerably reduced by the presence of the mounting adhesives, especially the fastening adhesives of the panty. On the other hand, this problem is particularly acute in the central region of the absorbent article where breathability is especially desirable, but where the absence of the adhesive results in the piling up of the product. Although this problem has been recognized in the art, the proposed solutions only relate to keeping the surface area of the adhesive to a minimum. However, these solutions have not proved to be satisfactory, in terms of the permeability of the wet vapor against the fixation of the product to the undergarment, as an exchange between the breathability and the proper functioning of the adhesive is required. Moreover, still another problem related to the reduction of the surface area protection of the adhesive is that the adhesive helps to ensure the liquid impermeability of the breathable backsheets in certain locations subject to stress and thus prevent leakage. In this way, a reduction in surface area can also result in an increase in rewetting through the breathable backsheet. It is therefore another object of the present invention to provide an absorbent article having a wet vapor permeable backsheet and a panty mounting or fastening adhesive configuration that is positioned to provide the required fixation between the two adjacent surfaces, while not significantly reducing the rate of transport of wet steam from the backsheet. Surprisingly, it has now been found that these objectives can be met by applying an adhesive to one of the surfaces that are joined to provide at least two different basis weight areas of adhesive. In this way, the adhesive can be applied to the high basis weight to the areas of the product that are exposed to high stresses, such as the periphery, while the adhesive can be applied to lower basis weight in the central regions, for example, where The product experiences less effort. Also, the high base weight adhesive can be applied in areas where high breathability is not required, such as the periphery and a low basis weight in the central regions where respirability is required. Moreover, it has also been advantageously identified, that the adhesive, particularly the fastening adhesive of the panty can be applied to the areas of the breathable backsheet which are susceptible to rewetting of the backsheet, for example in the area in the periphery of the core, where the materials of the upper sheet can be in direct contact with the materials of the back sheet or in the fold lines of packaging of the product. Yet a further advantage of the present invention is that the panty fastening adhesive can be applied in low basis weight or most preferably an adhesive free zone can be provided in the periphery particularly in the outer corners of the product to allow for easy manipulation of the product by the consumer.

BRIEF DESCRIPTION OF THE INVENTION The present invention relates to an improved application of the adhesive useful for the construction of the absorbent articles. In particular, the present invention relates to the joining of two adjacent surfaces of the components of the absorbent article by adhesive. The adhesive is applied to one of the surfaces to be joined to provide an adhesive area. The adhesive area has at least two zones, a first zone and a second zone, wherein the first zone of the adhesive has a base weight greater than that of the second zone and wherein the first zone is preferably located towards the periphery of the article. . In accordance with the present invention, the adhesive area can also provide a releasable fastening means as is typical between a release paper or a release film and a panty fastening adhesive, in addition to providing a permanent connection between the adjacent layers .

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows the surface that gives the garment of a formed sanitary napkin having an area of panty fastening adhesive according to the present invention, which has a first area of high basis weight having two areas that extend longitudinally along the edges of the towel, a second zone of smaller basis weight extending longitudinally in the center and four zones free of adhesive in the periphery. Figure 2 shows an alternative embodiment of the panty fastening adhesive area according to the present invention, which has a first zone of singular high basis weight and three lower base weight zones extending longitudinally in the center of the towel. Figure 3 shows an alternative embodiment of the fastening adhesive area of the pant of Figure 1, wherein the second zone is surrounded by a first singular zone. Figure 4 shows another alternative embodiment having two first high basis weight zones extending laterally on the fold lines of the product, three lower second weight areas and four adhesive free zones at the periphery.

DETAILED DESCRIPTION OF THE INVENTION The absorbent article of the present invention has a user-facing surface, typically provided by a liquid permeable fiber substrate or a film-like structure named top sheet; a surface that gives the garment preferably provided by a liquid impermeable substrate, referred to as a backsheet which is also permeable to moist and therefore breathable vapor and, an absorbent structure placed between the surface that gives the wearer and the surface that gives the garment, typically named the absorbent core. The absorbent article may comprise any of the components or features normal in the art, in particular side wrapping elements, side flap components or wings as well as any type of extensibility or elasticizing characteristic. For example, a typical sanitary napkin or pantyhose comprises an adhesive area on the surface that to the garment of the backsheet providing the panty fastening adhesive which is covered by a release paper, wrapper or the like before use from the article. The absorbent article for absorbing liquids is described below with reference to a sanitary napkin or a pantiprotector. However, products such as adult or baby diapers, or incontinence products that comprise adhesives can similarly benefit from the process of the present invention. Adhesives suitable for use in the present invention can be any adhesive known in the art to provide permanent or peelable attachment between two adjacent surfaces, such as thermal fusion adhesives., typically used for the fastening adhesive of the panty, water-based adhesives, cold adhesives and the like commonly used as mounting adhesives. Typically, thermal melt adhesives, typically comprising a thermoplastic base material, in combination with a tackifying resin, and mineral oils or waxes or a mixture of several of these materials are preferred. Typical thermal melt adhesives have a minimum melting temperature of about 80 ° C, often even about 100 ° C. The requirement for these thermal melt adhesives is of course that they maintain their adhesive performance until the disposal of the disposable absorbent article, that is, during manufacture, storage, transportation and use of the disposable absorbent article. Typically, the highest temperature during these activities is the temperature of use at about 40 ° C when the disposable absorbent article is used in a human body. However, higher temperatures may occur, for example, when articles are left in a vehicle in the sun, where temperatures of 60 ° C and above have been reported.

In accordance with the present invention the top sheet, back sheet and absorbent core components are joined together 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 the components of the absorbent article comprises at least one layer having a surface that gives the wearer and a surface that to the garment. Typically, the surfaces that give the garment form a common interface with the surface that gives the wearer an adjacent component or layer. The components or layers are joined together through their common interface. In this way, the top sheet is attached to the absorbent core, and the core is attached to the backsheet. In addition each of the topsheet, the backsheet and the core components can comprise more than one layer and these layers can also be joined in a similar manner. In addition, the topsheet may be directly or indirectly attached to the backsheet at the periphery of the absorbent article and on the wings if present. In addition, particularly for the sanitary napkin, panty-protector and incontinence product applications, the garment surface of the backsheet provides the surface to which the absorbent article is attached to the garment of the product user. to provide the panty fastening adhesive. Similarly if the product is a winged product, the wings are also provided with the adhesive in order to secure the wings to the surface that gives the garment of the undergarment. These surfaces are typically provided with protective covers that are removed before use. Therefore, according to the present invention, at least one of the surfaces that the user gives to the garment of the components of the topsheet, the core or the backsheet comprises an adhesive. Preferably, at least the surface that gives the garment of the backsheet is applied with an adhesive area according to the present invention. More preferably at least the garment facing surface of the backsheet and at least one of another surface are joined to another by application of the adhesive area of the present invention and most preferably all of the common interfaces of the The components of the article are joined together by the application of the adhesive in the manner of the present invention. The present invention will now be described with reference to the application of a panty fastening adhesive to the garment facing surface of the backsheet. However, as discussed here above the invention is equally applicable for the adhesion of the common interface between any of the other surfaces of the absorbent article. According to a preferred embodiment of the present invention wherein the absorbent article finds utility as a sanitary napkin (1) or panty protection, the adhesive that gives the garment of the backsheet is applied to provide the article with a means of fastening the panty which provides the means to fix the article to the surface that gives the user of the undergarment. In addition, the panty fastening adhesive preferably provides a means for securing the article when soiled, for folding and wrapping packaging for convenient disposal. Typically, at least one part that faces the garment surface of the backsheet is coated with a pressure sensitive adhesive to form the panty fastening adhesive. The panty fastening adhesives may comprise any adhesive used in the art for such purposes. These adhesives are typically sensitive to pressure and remain tacky below their application temperature. The suitable non-extensible adhesives are Savare LA203 manufactured by Savare I. O Milan, Italy and Fuller H-2238ZP manufactured by H.B. Fuller Co. in Lueneburg, Germany. Suitable adhesive fasteners are also described in U.S. Patent No. 4 917 697. Before using the absorbent article, the panty fastening adhesive is typically protected from contamination and adhering to another surface where it is not desired. , by means of a covering protective member such as a release paper coated with silicone, a plastic film, or any other easily removable cover. The protective cover member can be provided as a single piece or a multitude of pieces, for example, to cover the individual areas of the adhesive. It can also perform other functions such as providing individual packing for the article or providing a function for disposal. Any commercially available release paper or film can be used. Suitable examples include BL 30MG-A SILOX O / O, BL 30MG-A SILOX 4 P / O available from Akrosil Corporation, and M & amp;; M available from Gronau in Germany, under code X-5432. The adhesive can be applied to the surface using any of the methods well known in the art for this purpose such as slot coating, spraying and roller printing. With the development of adhesive printing as described for example in European patent EP 745 432, European patent EP 745 433, and in European patent EP 745 368, it has now also become possible to provide said adhesive for fastening the panty in any desired form and therefore these methods are particularly preferred in the present invention. Preferably, the panty fastening adhesive is applied in intermittent patterns such as intermittent microscopic dot, intermittent strips, lines or grids, or other designed shapes such as circles. If the side flaps or protective wings are present then they can also be provided with optional fasteners thereon for additional safety. The fasteners help the protective side flaps remain in position after they have been wrapped around the edges of the crotch surface of the undergarment by adhering to the surface that it gives to the garment of the undergarment. Therefore, the adhesive area applied to the wings is independent of the adhesive area applied as the so-called adhesive of the panty on the back sheet. The fasteners of the side flaps can also be applied with adhesive areas according to the present invention and are also typically covered with protective cover member. According to the present invention one of the surfaces that are joined to the other surface is applied with adhesive to provide an adhesive area (2). Furthermore, this adhesive area (2) comprises at least two areas of adhesive, a first zone (3) and a second zone (4), wherein the first zone has a base weight of adhesive greater than that of the second zone. Actually, this is also easily identifiable by the type of different adhesives used for the panty fastening adhesive and the adhesive used to adhere the wings to the underside or to the surface that it gives to the garment of the undergarment. Similarly, for embodiments where the adhesive area comprises areas of multiple zones, each subsequent adhesive zone is distinguished from the following zone because the base weight of the adhesive is reduced. Preferably, the adhesive area comprises two zones, but may comprise three or more areas of adhesive. In accordance with the present invention each zone of adhesive is identifiable by the basis weight of the adhesive application and is typically recognizable by the human eye. Each zone may therefore comprise a simple adhesive application or alternatively may comprise an application of adhesive spots with microscopic pattern for example or may comprise a number of simple adhesive areas or with microscopic patterns having the same base weight of adhesive as illustrated in Figures 1, 2 and 4. The variation in the base weight of adhesive can be achieved by a number of means. For methods involving roller printing this can be simply achieved by varying the size of the dots, varying the separations of the dots, or a combination of both as illustrated in Figure 1. For other application methods such as spraying , spiral bonding and slot coating this can be achieved by applying different amounts per unit of time in different areas of the adhesive pad, or by varying the amount of adhesive applied during the application cycle for each pad. Alternatively, different base weights can also be achieved by applying different adhesives. According to the present invention, the ratio between the basis weight of the first (3) and second (4) zones of an adhesive area is typically in the range of 1: 1.5 to 1: 20., more preferably from 1: 2 to 1:10, most preferably from 1: 2 to 1: 5. Similarly, for embodiments where the adhesive area comprises three or more zones the ratio between zone two and three and subsequent areas of adhesive is from 1: 1.5 to 1: 20, preferably from 1: 2 to 1: 10, most preferably from 1: 2 to 1: 5. Typically the amount of actual adhesive that is applied in a particular area also depends on the type of absorbent article itself and the physical and chemical nature of the materials of the surfaces to be joined. Preferably, the adhesive is applied at a basis weight of 1 g / m2 to 60 g / m2, in each zone. For adhesive applications for bonding the components of the article such as the topsheet, the core and the backsheet, the basis weight is typically from 2g / m2 to 20g / m2, more preferably from 3g / m2 to 15g / m2. Some non-tacky weld-type assembly adhesives as disclosed in European Patent EP 707 841 may, however, be applied at a basis weight of 20g / m2 to 50g / m2.

For application as a panty fastening adhesive the adhesive is typically applied at a basis weight of 5g / m2 to 50g / m2, preferably 12g / m2 to 25g / m2. In a preferred embodiment, the first area of the panty fastening adhesive is applied from 15 g / m2 to 50 g / m2, and the second zone is applied to a basis weight of 5 g / m2 to 15 g / m2. According to the present invention the areas of the adhesive area can be located in any position on the surface to be joined. However, the adhesive areas are preferably positioned in such a way as to provide areas with higher density towards the periphery (5) of the surfaces to be joined and areas with lower density towards the center of the surface to allow maximum breathability through the center of the product where this is most desired. Typically, as illustrated in Figures 1, 2 and 3, the first zone (3) having the highest adhesive density is located towards the periphery of the product and preferably extends around the total periphery (5) or from a short distance of 1 mm to 6 mm, from there by an equal distance, preferably approximately 10 mm in width, from there to the center. The second zone (4) of the adhesive can be located immediately adjacent to the first zone (3) or alternatively there can be a zone free of adhesive or a third zone with additional lower density located between the first and second zones. In a particularly preferred embodiment of the present invention, the surface has at least one, preferably at least two and most preferably at least four adhesive-free areas. The adhesive-free areas can be located anywhere on said surface, such as towards the center or towards the periphery of the product. However, it has been found to be particularly effective to provide said adhesive-free zones towards the periphery, most preferably at the outermost periphery of the product as illustrated in Figures 1, 2 and 3 by (6). In this way the easy handling by the consumer of the product is ensured in such a way that the product can be applied and removed from the undergarment without the need for the consumer to make contact with the adhesive surface and while also maintaining the desired adhesion. Typically, the surface is provided with a symmetric distribution of the zones, as in Figures 1, 2 and 3, however, the distribution of the zone may also be asymmetric. In another embodiment of the present invention as illustrated in Figure 5, the first zone (3) of the adhesive is applied along the fold lines of the product and the second zone of reduced basis weight (4) is applied through of the remaining surface area separated from the outermost corners (6) which remain free of adhesive. This modality, although it ensures the maintenance of the breathability in the center of the product, also protects against the potential weakening of the product in the fold lines that result in leaks through the backsheet. Similarly, in another embodiment of the present invention as illustrated in Figure 3, the elevated basis weight of the first adhesive zone (3) is applied such that it extends from the periphery to the center such that this zone extends. towards the core region (7). In this way the potential leak is avoided due to the direct contact of the materials of the upper sheet with the back sheet. Although it is preferred that the components of the article also be bonded to each other using the adhesive area application of the present invention, these surfaces may also be joined by other means, known in the art to fix two adjacent layers of material, such that the layers are attached directly to one another or fixed directly to one another by means of joining means. Suitable bonding means include fusion bonding, ultrasonic bonding, stitching, heat (eg, pleating), embossing, and / or pressure bonds, or mechanical dynamic bonds.

In order to fully determine the usefulness of the process of the present í * > invention a description of a typical disposable absorbent article follows.

The upper sheet 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 topsheet is permeable to fluid allowing fluids (eg, menstruation, and / or urine) to easily penetrate through its thickness. A suitable top sheet can be manufactured from a wide range of materials such * as woven and non-woven materials; polymeric materials such as thermoplastic films formed with openings, plastic films with openings, and hydroformed thermoplastic films; and thermoplastic canvases. 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 fibers of two / multi components. Preferred top sheets for use in the present invention are selected from high-bulk non-woven upper sheets and upper sheets of film formed with openings. 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 the 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 thus 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; U.S. Patent 4,324,246; U.S. Patent No. 4,342,314; 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 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 which do not have a homogeneous distribution of 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 liquid impervious. The body surface of the formed film top sheet can be hydrophilic to help transfer the liquid through the top sheet faster 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 No. 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 are so-called hybrid top sheets which incorporate fibrous and film-like structures, particularly useful embodiments of these hybrid top sheets are disclosed in PCT Publication No. WO 93/09744; WO 93/11725 or WO 93/1 1726.

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 preferred side flaps, the side wrapping elements or wings. When reference is made to the top sheet, a multilayer structure or a single layer structure is contemplated. The aforementioned hybrid top sheet is said multiple layer design but other multilayer top sheets such as the primary and secondary top sheet designs are also considered.

Absorbent core 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 multiple layers of material whose primary function is to absorb, store and distribute the fluid. In accordance with the present invention, the absorbent core may include the following components: (a) a primary fluid distribution layer optionally preferably together with an optional secondary fluid distribution layer; (b) a fluid storage layer; (c) an optional fibrous layer ("dedusting") that is below the storage layer; and (d) other optional components. a Primary / secondary fluid distribution layer 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 with it. The upper sheet transfers the acquired fluid to this primary distribution layer for the final distribution to the storage layer. This transfer of fluid through the primary distribution layer occurs not only in the thickness, but also along the length and width directions of the absorbent product. The also optional but preferred secondary distribution layer is typically below the primary distribution layer and is in fluid communication with it. The purpose of this secondary distribution layer is to rapidly acquire the fluid from the primary distribution layer and transfer it rapidly to the underlying storage layer. This helps to fully utilize the fluid capacity of the underlying storage layer. 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 in addition to the gelling absorbent material which can be provided within the odor control particles of the present invention, usually referred to as "hydrogelling," superabsorbent7"hydrocolloid" materials in combination with carriers. adequate.

The gelling absorbent materials are capable of absorbing large quantities of aqueous body fluids, and are also capable of retaining these absorbed fluids under moderate pressures. The gelling absorbent materials may be dispersed homogeneously or in a non-homogeneous manner within 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 very often comprise a polymeric gelling material, partially neutralized, slightly crosslinked, substantially insoluble in water. This material forms a hydrogel when in contact with water. These polymeric materials can be prepared from acid-containing, unsaturated, polymerizable 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 together with the gelling absorbent material, however, these can also be used alone or in combinations. Tissue and tissue laminates are very preferred within the context of sanitary napkins and pantiliners. One embodiment of the absorbent structure made in accordance with the present invention comprises a double-layer tissue laminate formed by folding the tissue over itself. These layers can be joined together, for example, by adhesive or mechanical interlacing or by bands of hydrogen bridges. The gelling absorbent material or other optional material 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 of cellulose acetate, polyvinyl fluoride, polyvinylidene chloride, acrylics (such as Orion), 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 surface of the fiber is hydrophilic or is treated to be hydrophilic. The storage layer may also include filler materials, such as perlite, diatomaceous earth, vermiculite, etc. to improve fluid retention. If the gelling absorbent material is homogeneously dispersed in a carrier, the storage layer may however be locally homogeneous, ie have a distribution gradient in one or several directions within the dimensions of the storage layer. The inhomogeneous distribution can also refer to the laminates of the carriers that enclose the gelling absorbent materials partially or totally. c Optional fibrous layer ("dust removal") 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 as it provides a substrate on which the absorbent gelling material is deposited in the storage layer during the manufacture of the absorbent core. In fact, in those examples where the gelling absorbent material is in the form of macro structures such as fibers, sheets or strips, it is not necessary to include this fibrous "dedusting" layer. However, this "dedusting" layer provides some of the additional fluid handling capabilities such as capillary action or rapid wicking effect 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 must be of such configuration so as not to form interfacial barriers to 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 in the absorbent core according to the invention and preferably is provided near or as part of the first and second fluid distribution layers are the odor control agents.

Back sheet The back sheet mainly prevents the exudates absorbed and contained in the absorbent structure from wetting the articles that are in contact with the absorbent product such as underpants, pants, pajamas and undergarments. The backsheet is preferably impermeable to liquids (eg, menstruation and / or urine) and is preferably manufactured from a thin plastic film, although other flexible liquid impervious materials may also be used. As used herein, the term "flexible" refers to materials that are docile and that will easily conform to the figure and general contour of the human body. The back sheet can also have elastic characteristics that allow it to stretch in one or two directions. The backsheet typically extends through the entire absorbent structure and can extend into and form part of all or of the preferred fins, from the lateral elements unwrap or the wings. In accordance with the present invention, the backsheet of the absorbent article is breathable such that it is permeable to wet vapor and thus comprises a gas permeable layer. Suitable gas permeable layers include two-dimensional, flat micro and macro porous films, macroscopically expanded films, apertured films formed and monolithic films. According to the present invention the openings in said layer can be of any configuration, but are preferably spherical or oblong and can also be variable dimensions. 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. Suitable two-dimensional 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, Gortex (TM) or Sympatex (TM) type materials well known in the art for their application in the so-called breathable garment. 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 "two-dimensional plan layer" refers to the layers having a depth of less than 1 mm, preferably less than 0.5 mm, wherein the openings have a uniform average diameter along their length and which does not protrude beyond the plane of the layer. Materials with openings for use herein 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 the reference thereto. 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 the films having discrete apertures extending beyond the horizontal plane of the surface that gives the garment layer to the core, thereby forming the protuberances. The protuberances have a hole located at their terminal end. Preferably, the protuberances are of a funnel shape similar to those described in U.S. Patent No. 3,929,135. The openings located within the plane in the holes located at the terminal end of the protuberances themselves can be circular or noncircular as long as the dimension or cross-sectional area of the hole at the termination of the protrusion is smaller than the dimension or area in section cross section of the opening located inside the surface that gives the clothing of the layer. Preferably, said apertured preformed films are unidirectional such that they have at least substantially, if not completely, a directional 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 Index 93 Congress, Session 7A "Adding Value to Nonwovens", JC Cardinal and Y. Trouilhet, DuPont de Nemours International, SA, Switzerland, such as Pebax ™ , available from Elf Atochem (France) and Estañe ™ available from Goodrich (Belgium). Preferred backsheets for the present invention comprise at least two layers comprising at least one layer selected from the previous ones, such as microporous films and films formed with openings and an additional layer which can be selected from the back sheets listed above or can be a fibrous fabric or a nonwoven material. The highly preferred component of the breathable backsheet comprises a microporous film and a film formed with openings or a microporous film and a hydrophobic woven or nonwoven material.

Claims (10)

1. An absorbent article comprising an upper sheet, a breathable back sheet and an absorbent core, the core being located between the upper sheet and the back sheet, each of the upper sheet, the core and the back sheet having a surface that gives the garment and a surface that gives the user and at least one of the surfaces that it gives to the user or the surfaces that give the garment comprising an adhesive area, characterized in that said adhesive area comprises at least two areas, one first zone and a second zone, wherein the first has an application of base weight of adhesive that is greater than the application of base weight of the adhesive of the second zone.

2. An absorbent article according to claim 1, wherein the ratio of the base weight of the adhesive of the first zone to the second zone is from 1: 1.5 to 1: 20.

An absorbent article according to any of claims 1 or 2, wherein the surface that gives the garment comprises further a third zone of adhesive, said third zone having a base weight application of adhesive with respect to said adhesive. second zone from 1: 1.5 to 1: 20.

4. An absorbent article according to any of the preceding claims, said article having a peripheral edge, wherein at least one position of said first zone extends from the peripheral edge.

An absorbent article according to any of the preceding claims, wherein the adhesive areas are comprised of adhesive patterns selected from irregular and regular shapes, dots, rings, lines or grids.

6. An absorbent article according to any of the preceding claims, wherein the surface that gives the garment comprises at least one adhesive-free zone.

An absorbent article according to any one of the preceding claims, wherein the backsheet comprises at least one first layer selected from microporous films, macroporous films, films formed with openings and monolithic films.

An absorbent article according to claim 7, wherein the backsheet comprises a second layer, selected from microporous films, macroporous films, films formed with openings, monolithic films, fibrous fabrics and fibrous nonwoven materials.

An absorbent article according to any one of the preceding claims, wherein the apparel-facing surface comprises said adhesive area and said adhesive area further comprises a removable cover protective member.

10. An absorbent article in accordance with any of the foregoing claims, wherein said absorbent article is a sanitary napkin or a pantyhose.