MXPA97003157A - Absorbent articles flexible and permeable to the water vapor, and its fixation to the clothing inter - Google Patents

Abstract

The present invention relates to absorbent articles permeable to water vapor, such as, for example, sanitary napkins, pantiliners, and incontinence pads which adhere by means of adhesives (22) to a prendaintimate, during its use. More particularly, the present invention relates to articles having a backsheet permeable to water vapor and having a flexibility in the longitudinal direction and, also, that in particular can adhere well to the undergarment in order to provide improved comfort for the user of the article

Description

ABSORBENT ARTICLES FLEXIBLE AND PERMEABLE TO WATER VAPOR. AND Sü FIXATION TO THE INTERIOR CLOTHING FIELD OF THE INVENTION The present invention relates to absorbent articles permeable to water vapor, such as sanitary napkins, pantiliners and incontinence pads that adhere to an undergarment during use. More particularly, the present invention relates to articles that are water vapor permeable and that have a flexibility in a longitudinal direction that provides improved comfort for the user of the article.

BACKGROUND DB THE INVENTION Disposable absorbent articles such as baby diapers, incontinence articles for adults, sanitary napkins and panty-protectors, are well known in the art. These items have a user-oriented side through which they typically absorb liquids discarded by the user. The liquid is stored in an absorbent structure. The leakage of liquids from the article, through the surface opposite to the side facing the user, is normally avoided by incorporating on that side a backing sheet impervious to the liquid. It is well established in this field that the backing sheets allow the communication of air with the environment and normally that characteristic is called breathing capacity or breathability, which is quite desirable for this material. Breathability improves with the amount of air that permeates through a backing sheet. This amount is proportional to the open area (the sum of the area of all the openings) in the backup sheet. Obviously, improvements in breathability lead to compromising the prevention of fluid leakage, which is the primary function of the backup sheet. Many suggestions of how to provide the breathability characteristic to backing sheets are recorded in the art. Several attempts have been made to combine the mutual contradictory particularities of gas permeability and liquid impermeability, all documented in applications and patent titles. However, the lack of commercial availability of these disposable absorbent articles with breathability characteristics and which are also very flexible, indicates that the technology hitherto suggested has not provided a totally satisfactory result for the desired technical requirements in P406 commercially acceptable conditions. Sanitary napkins, pantiliners and incontinence pads are typically used in the crotch region of an undergarment and are attached to the garment by the so-called undergarment adhesive. These articles are intended for daily use and providing them with the particularity of breathability is desirable in order to increase the comfort experienced by the user of these articles. In particular, it is believed that the loss of water vapor from these articles provides a lower sensation of sweating, heat and suffocation. It has also been well established that in order to make these items more comfortable for the user they need to be flexible. It is believed that the more flexible an absorbent article is, the less it will be noticeable to the user. Therefore, this gives you a sense of comfort by more closely resembling a situation where the absorbent article is not being used. Flexibility can be easily achieved by reducing the amount of material in the absorbent article or by replacing rigid and inflexible components with other more flexible components. However, for a long time it has been recognized that extreme flexibility can also reduce the absorbent performance of these articles, for example by an insufficient amount of absorbent material or by a clumping or densification of the absorbent material during use. An article that is too flexible can be difficult for the user to handle when adhering to the undergarment. The problem of too much flexibility in an article, because of the low amount of inflexible material, it has been focused for example in U.S. Patent No. 4,217,901, wherein particularly the stiffness of an absorbent article increases in order to provide satisfactory performance. This prior art reference accepts the comfort implications caused by this stiffness requirement. This document also does not consider breathability. Therefore, the most desirable are absorbent articles that have a high degree of flexibility and breathability. However, providing a backed sheet with openings together with a flexible article, ie a thin absorbent article, would accept too much risk of leakage through the backing sheet. Therefore, the lack of breathability of the backing sheet has been accepted to date so as not to sacrifice the prevention of leaks, especially for thin absorbent products. Only today, breathable, capable, novel, breathable backing sheets suggested in simultaneously filed applications entitled "Breathable backsheet design for disposable absorbent articles" and "Breathable dual layer backing sheet design for articles" could be considered as alternatives. Disposable Absorbents ", both assigned to The Procter and Gamble Company and designed by M. Depner and M. Divo, as co-inventors. However, even these multilayer backsheet designs are to some extent counterproducers of improved flexibility, due to the addition of the multiple layers which increases stiffness instead of supporting flexibility. Other attempts of the prior art to provide breathable backsheet units comprising more than one layer are, for example, patent documents US 4,341,216; EP-A-109 126 or EP-A-203 821. Breathable single-layer backing sheets are known, for example, from GB-A-2184391, GB-A-2184390, GB-A-2184389, US 4,591,523, US 4,839,216 or EP 156471. None of the above-mentioned exposures, however, attempts to focus on the comfort problems associated with rigidity or with absorbent articles that are not sufficiently flexible. Some of them even suggest providing sufficient absorbent material to cover situations of possible leaks. However, this means increasing stiffness at the expense of breathability. Therefore, an objective of this invention is to focus on the problem of the conflict between leakage through the backing sheet, flexibility and breathability. The benefits of breathability and flexibility, in particular, the ability to bend and twist easily in the longitudinal direction and preferably in all directions, have become quite important, especially for absorbent articles for daily use, such as panty-scrubs, sanitary napkins and incontinence pads. To date it has been found that the leakage problem, associated with breathable and open-backed backing sheets, can be avoided by substantially maintaining, at the same time, the benefit of the use of water vapor permeable films. At the same time, the comfort of the absorbent articles can be drastically improved when a high flexibility in the longitudinal direction is provided, in combination with a particular configuration of panty fastening adhesive, in order to keep the articles permeable to water vapor in the form flat in relation to the user's undergarment. The flexibility is then limited only by the strength requirements of materials and by handling requirements of the absorbent article. Therefore, an object of this invention is to provide sanitary napkins with improved flexibility, without previously experienced problems. In particular, a high degree of flexibility and the benefits of breathability, without putting openings in the backing sheet, in the absence of stacking problems or greater handling difficulties, is achieved by the selected intervals of the design parameters of the articles , according to the present invention. These and other objects of the invention will be more readily apparent when considered in relation to the following description.

SUMMARY OF THE INVENTION The present invention provides an absorbent article, permeable to water vapor, for example a sanitary napkin, an incontinence pad and, in particular, panty-protectors, which are used in an intimate garment. The absorbent article has a backsheet permeable to water vapor, which has no openings and which comprises a garment facing surface. On the surface facing the garment is an adhesive that will adhere to the article on the garment. The article may optionally comprise protective side flaps which, during use, are folded around the side edges of the crotch region of the garment, in order to improve the protection against staining of the garment. The absorbent article also comprises other components typical of these articles, mainly the absorbent core and a user-oriented and liquid-permeable surface, which is preferably provided by a liquid-permeable top sheet. The absorbent article comprises a water vapor permeable backsheet which normally provides the garment facing surface of the absorbent article. If the upper sheet and the backing sheet are present, the absorbent core is enclosed by them on the user and on the side of the garment, respectively. The adhesive can be provided throughout the entire or part of the garment-oriented surface or in different parts of the garment. The adhesive is provided in order to stick to the entire surface area. If it completely covers the surface facing the garment it can be in the form of filaments, which are in a random design or in a defined design similar to spirals. The total area of all the adhesive on the garment facing surface of the absorbent article defines the actual surface of the adhesive. Also I know P406 provides a theoretical adhesion surface by the periphery of an endless line which is the shortest surrounding glue line, without extending beyond the periphery of the garment facing surface itself. The absorbent article according to the invention has a surface proportion of the theoretical adhesion surface relative to the garment facing surface within the range of 0.6 to 1, preferably 0.85 to 1 for articles without protective side flaps, and in a range of 0.5 to 1, preferably from 0.7 to 0.9, for articles with protective lateral fins. In a preferred embodiment, the theoretical bonding surface is substantially coextensive with the actual surface covered by the adhesive. In order to obtain the benefits of the present invention, the absorbent article as a whole, needs to provide exceptional flexibility. The flexibility is measured by the modified ASTM method D1388, as described below, in the longitudinal direction. The expression "flexibility" is also referred to as "fall" due to the particular method. It should be understood that rigidity is characteristic of the opposite behavior of a material. The flexibility should be in the range of 1300 to 5000, preferably P406 from 2000 to 3500, and more preferably from 2000 to 3000, mg x cm. These values of flexibility in combination with the superficial proportion, indicated above, provide an exceptional comfort to the user without problems of staining and / or performance of the absorbent material, due to accumulation or densification of absorbent material, and still allows the user to join the article to the pledge, without much effort. According to the present invention, flexibility is measured in the longitudinal direction since it is the most easily measurable and most important value. In principle, transverse flexibility can also be used, possibly at different values. Due to the small extension to the articles in the transverse direction, it is usually not possible to adequately measure flexibility in this direction. The thickness or thickness of a preferred embodiment of the present invention, especially for panty-protectors, is less than 3 mm and, still more preferably, is in the range of 0.5 to 1.5 mm, according to the thickness measurement with the method which is described below. The proper combination of flexibility and adhesive coverage for fastening to garments is particularly useful in the context of stretchable absorbent articles. Absorbent items that are P406 stretchable in one direction and also absorbent articles that are stretchable in two directions (or all directions) are inherently flexible. Stretching capacity by itself already provides an improvement in comfort, so that absorbent articles that combine stretchability with the present invention are particularly desirable. Also particularly useful are stretchable absorbent articles having draw characteristics such as those described in United States application number 08 / 192,240, filed on February 4, 1994 and indicated in the Table of Figure 7, and the respective description of that request. The second key aspect according to the invention is the water vapor permeability of the backing sheet of the absorbent articles. The articles according to the present invention have a backsheet permeable to water vapor without openings. The backing sheet is impervious to liquid. To accomplish this, the backing sheet comprises a sheet permeable to water vapor that is also impervious to liquid. It can be provided with one or more additional layers that provide different functions. In particular, it can have, for example, a very thin film of thermoplastic material permeable to water vapor, provided, P406 for example, another discontinuous film having openings (in order to retard the permeability of water vapor) but which improves the strength of the material and / or even another layer to provide, for example, desirable appearance, such as a fibrous layer on the garment-facing side of the backing sheet, so that it resembles the appearance of a cloth.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a plan view of a pantiprotector with protective lateral flaps seen from the garment facing surface, according to the present invention. Figure 2 shows a sanitary napkin having protective side flaps, as seen from the garment facing surface, according to an alternative embodiment of the present invention.

DETAILED DESCRIPTION OF THE PRESENT INVENTION The present invention will be described in relation to panty-protectors. However, it can also be applied to sanitary napkins or incontinence articles for adults, which are used in an intimate garment and are attached to the garment during the use of the absorbent article. The absorbent articles according to the P406 invention typically comprises three main components: a liquid pervious top sheet, a water vapor permeable backing sheet and an absorbent core. The absorbent core is enclosed by the back sheet and the top sheet and the article is used so that the exposed surface of the top sheet is oriented towards the user of the article, while the surface exposed to the back sheet is oriented towards the garment to which the article is to be adhered, by means of a means of adhesion for the subjection to the garment. Typically, it is an adhesive but it could also be a mechanical bond. The present invention relates to the flexibility of the article and the water vapor permeability. The degree of flexibility is determined by the selection of materials for the components of the article, as already mentioned, and their respective quantity. It will be apparent to those with experience in this field that, in order to achieve flexibility according to the present invention, the selection of the kind and quantity of primary materials must be balanced with other desired characteristics of the absorbent article, such as, for example, absorbent capacity, absorption speed and dryness of the surface on the outside of the upper sheet, during use.

P406 Therefore, the following description of typical materials of the main components of the absorbent article, will allow to provide an almost infinite number of variants of articles within the limitations of internal and external flexibility, for the present invention. The fact that the absorbent article complies with the flexibility requirements of the present invention can be confirmed by the simple measurements carried out according to the method described below. The absorbent articles according to a preferred embodiment of this invention can stretch elastically. The term "stretched elastic", in the sense used herein, refers to that when pulling forces are removed, the article will tend to return to its non-stretched or unstretched condition (or "original • dimensions). However, it is not necessary to return fully to its unstretched dimensions. If the absorbent article can be elastically stretched it can be stretchable in one or both directions (which are not parallel) within the plane of the article, ie parallel to the garment facing surfaces. The materials for elastically stretching the articles may per se be elastically stretchable or P40ß can be treated in order to provide them with this elastic stretch ability. In particular, the elastic backsheet material, the upper elastic sheet material, the filamentary materials combined with threads, threads or elastic webs, as well as the wrinkling, folding or ring rolling of the materials, can be employed in this context. Suitable methods and materials are known in the art and are disclosed, for example in detail in the specially-referenced US Patent Application No. 08/192240 of February 4, 1994, to facilitate the selection of materials if stretchable absorbent articles are to be made according to the present invention. Next, the non-limiting modalities of the main elements of the absorbent article that can be used in elastically stretchable designs or non-stretchable designs are described.

Absorbent core The absorbent core typically includes the following components: (a) optionally a primary fluid distribution layer; (b) optionally, but not preferentially, a secondary fluid distribution layer; (c) a fluid storage layer; (d) optionally a fibrous ("powdery") layer that P406 underlies the storage layer; and (e) other optional components. a »Primary fluid distribution layer An optional component of the absorbent cores according to the present invention is the primary fluid distribution layer. This primary distribution layer is typically underlying the upper sheet and is in fluid communication with it. The upper layer transfers the acquired menstrual fluid to this primary distribution layer, for its 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 in the width direction of the absorbent article. b. Optional secondary layer of fluid distribution Also optionally, but not as a preferred component of the absorbent cores according to the present invention, is a secondary fluid distribution layer. This secondary distribution layer is typically underlying the primary distribution layer and is in fluid communication with it. The purpose of this secondary layer of distribution is to easily acquire the menstrual fluid P406 from the primary distribution layer and quickly transfer it to the underlying storage layer. This helps the fluid capacity of the underlying storage layer to be fully utilized. c. Fluid storage layer Is placed in fluid communication with the primary and secondary distribution layers, and is typically underlying thereto, is a fluid storage layer comprising certain absorbent gelling materials and / or other absorbent materials, which can form the carrier matrix for the absorbent gelling materials. Absorbent gelling materials are commonly referred to as "hydrogels", "superabsorbent materials" and "hydrocolloids". The absorbent gelling materials are those materials that, in contact with aqueous fluids, especially aqueous body fluids, imbibe these fluids and in this way form hydrogels. These absorbent gelling materials are typically capable of absorbing large quantities of aqueous body fluids and, moreover, are capable of retaining these absorbed fluids under moderate pressures. These absorbent gelling materials are typically in the form of non-fibrous, discrete particles. The fluid storage layer may comprise P406 only absorbent gelling materials, or these absorbent gelling materials may be dispersed homogeneously or non-homogeneously in a suitable carrier, or they may comprise only an absorbent carrier material. Suitable carriers include cellulose fibers in the form of fluffs, fabrics or paper, in the form that is most convenient for use in the absorbent cores. Modified cellulose fibers, such as stiffened cellulose fibers, can be used. Synthetic fibers can also be used in include those made from cellulose acetate, polyvinyl fluoride, polyvinylidene chloride, acrylics (such as Orion), polyvinyl acetate, non-soluble polyvinyl alcohol, polyethylene, polypropylene, polyamides (e.g. nylon), polyesters, bicomponent fibers, tricomponent fibers, mixtures thereof and the like. Preferred synthetic fibers have a thickness of between about 3 denier per filament to about 25 denier per filament, more preferably from about 5 denier per filament to about 16 denier per filament. Also, preferably, the surfaces of the fibers are hydrophilic or are treated to be hydrophilic. The storage layer may also include filler or filler materials, such as pearlite, P406 diatomaceous earth, vermiculite, etc., which reduce rewetting problems. If it is dispersed in a non-homogeneous manner in a carrier, the storage layer can 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 laminates of carriers that enclose the absorbent gelling materials partially or totally. If absorbent gelling materials are present, the storage layer preferably comprises from about 15 to 100% absorbent gelling materials, and from 0 to about 85% carrier. Preferably, the storage layer comprises between about 30 to 100%, more preferably between about 60 to 100% of absorbent gelling materials, and 0 to 70%, more preferably about 0 to 40% of the carrier. Suitable gelling materials that are used here more often will comprise a polymeric gelling material, partially neutralized, slightly cross-linked and practically insoluble in water. These materials form a hydrogel upon contact with water. These polymeric materials can be prepared to P406 from unsaturated monomers, polymerizable, containing acid. The unsaturated acidic monomers that are used to prepare the polymeric absorbent gelling material used in this invention include those listed in U.S. Patent No. 4,654,039 and republication RE 32,649. Preferred monomers include acrylic acid, methacrylic acid and 2-acrylamido-2-methyl propan sulfonic acid. Acrylic acid by itself is especially preferred for the preparation of the polymeric gelling material. The polymer component formed from the unsaturated onomers, which contain acid, can be grafted onto other types of polymeric entities, such as starch or cellulose. Polyacrylate-grafted starch materials of this type are especially preferred. Preferred polymeric absorbent gelling materials that can be prepared from conventional types of monomers include hydrolyzed starch grafted with acrylonitrile, polyacrylate grafted starch, polyacrylates, maleic anhydride based copolymers and combinations thereof. Polyacrylate-grafted starches and polyacrylates are especially preferred. While these absorbent gelling materials are typically in particulate form, It is also contemplated that the absorbent gelling material may be in the form of macrostructures such as fibers, sheets or strips. These macrostructures are typically prepared by forming the particulate absorbent gelling material in the form of an aggregate, and treating the aggregate material with a suitable crosslinking agent, compacting the treated aggregate in order to densify it and form a coherent mass, and then curing the compacted aggregate to cause the crosslinking agent to react with the particulate absorbent gelling material and form a composite, absorbent and porous macrostructure. These absorbent and porous macrostructures are disclosed, for example, in U.S. Patent No. 5,102,597. d. Optional fibrous ("powdery") layer An optional component that is included in the absorbent cores according to the present invention is a fibrous layer adjacent to the storage layer and typically underlies it. The underlying fibrous layer is typically referred to as a "dusty" 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. This layer may comprise all those materials disclosed above P406 as carrier materials for the storage layer. In fact, in those cases where the absorbent gelling material is in the form of macrostructures, such as fibers, sheets or strips, this "powdery" fibrous layer needs to be included. However, as this "dusty" layer provides certain additional fluid handling skills, such as rapid dispersion of fluids along the length of the pad, its inclusion is typically preferred in absorbent cores according to the present invention.

H.H. Other optional components The absorbent cores according to the present invention can include other optional components normally present in the absorbent webs. For example, a thin reinforcing canvas can be placed within the respective layers, or between the respective layers, of the absorbent core. These thin reinforcement webs may have a configuration such that no interfacial barriers are formed for fluid transfer, especially if they are placed between respective layers of the absorbent core. Given the structural integrity that normally occurs as a result of thermal bonding, thin reinforcing canvases are not required for the absorbent structures according to the present invention, P406 and can in fact cause the desired flexibility to not be achieved. Another component that can be included in the absorbent core according to the invention, and is preferably provided near or as part of the primary or secondary fluid distribution layer, are the odor control agents. Typically the coated activated carbon or in addition other odor control agents, in particular clay or zeolite materials, are suitable, and are optimally incorporated in the absorbent core. These components can be incorporated in any desired form but, normally, they are included in non-fibrous and discrete particles.

Top sheet The top sheet is malleable, soft and non-irritating to the user's skin. As indicated above, the top sheet can also stretch elastically in one or two directions. In addition, the topsheet is permeable to fluids allowing fluids (ie menstrual fluid or urine) to easily penetrate through their thickness. A suitable top sheet can be manufactured from a wide variety of materials such as woven and non-woven materials; polymeric materials such as thermoplastic films that have openings, F406 plastic films with openings and hydroformed polyplastic films; porous foams; cross-linked foams; reticulated thermoplastic films and thin thermoplastic canvases. Suitable woven and non-woven materials may be comprised of natural fibers (e.g., wool or cotton fibers), synthetic fibers (e.g., polymer fibers such as polyesters, polypropylene, or polyethylene) or from a combination of natural and synthetic fibers . Preferred top sheets which are used in this invention are selected from high-malleability non-woven upper sheets and upper sheets of film having apertures formed therein. Films having formed openings are especially preferred for the topsheet as they are permeable to body exudates and, however, are non-absorbent and have a reduced tendency to allow fluids to return and rewet the user's skin. In this way, the surface of the formed film that is in contact with the body remains dry, thus reducing the body soiling and creating a more comfortable feeling for the user. Suitable formed films are described in U.S. Patent Nos. 3,929,135; 4,324,246; 4,342,314; 4,463,045; and 5,006,394. With particular preference, the upper film sheets are used P406 formed with micro apertures, set forth in U.S. Patent Nos. 4,609,518 and 4,629,643. Preferred top sheets for the present invention are in the form of the films described in one or more of the aforementioned patents and are marketed in sanitary napkins by The Procter & Gamble Company of Cincinnati, Ohio as "DRI-WEAVE". The top sheets which do not have a homogeneous distribution of liquid passage routes but only a portion of the top sheet comprises liquid passage routes are also useful in the present invention. Typically, the upper sheets will have the liquid passage routes oriented so as to result in an upper sheet that is centrally permeable and peripherally permeable to liquids. The body surface of the formed film topsheet can be hydrophilic in order to help liquids transfer through the topsheet more rapidly than if the body surface were not hydrophilic. In a preferred embodiment, the surfactant is incorporated into the polymeric materials of the formed film topsheet, as described in PCT application number US 92/09227. Alternatively, the body surface of the top sheet can be made hydrophilic by treating it with a surfactant, as described P406 in the aforementioned document US 4,950,254.

Water vapor permeable backing sheet The liquid permeable and water vapor permeable backing sheet prevents the exudate absorbed and contained in the absorbent core from wetting articles that are in contact with the sanitary napkin, for example, the panty, pajama or underwear. The backing sheet comprises at least one layer of the water vapor permeable material. The backing sheet may also comprise a polymeric film having openings to provide structural strength to the backing sheet. Also, a fibrous fabric layer, which particularly forms the garment facing surface, may be comprised of a backsheet. The water vapor permeable layer can be provided by a polymeric film having apertures of molecular size. The film may be, for example Goretex (TM) or Sympatex (TM) of well-known structure in this field to provide garments with breathable characteristics. Also, the films according to EP-A-293482 are considered useful in the context of this invention. Another example of a water vapor permeable film commercially available and useful as a backing sheet for this invention is that designated P406 XMP-1001 from Minnesota Mining and Manufacturing Company, St. Paul Minnesota, U.S.A.

The garment fastening adhesive The backing sheet typically forms the garment facing surface on which the garment fastening adhesive is placed. According to the present invention, it is important that the ratio of the theoretical adhesion surface to the garment orientation surface is within a range that is in accordance with that stated in the claims of the invention. The theoretical adhesion surface is defined by the surface area inside the shortest possible endless line surrounding the garment-bonded adhesive, without however extending beyond the periphery of the garment facing surface. In addition, the ratio of the actual adhesive surface to the garment orientation surface is in the range of 0.2 to 0.8. If for example there is a rectangular adhesive area on the garment facing surfaces, then the theoretical adhesion surfaces with respect to the actual adhesion surfaces are identical, this can be seen in Figure 1 where the adhesive 22 is indicated by a scratched on P406 diagonal. The surrounding line 26 results in a theoretical adhesion surface 24 identical to the surface covered by the adhesive 22. For absorbent articles having protective side flaps, Figure 2 shows that the three areas of adhesive 22 are smaller in the area of surface than the theoretical adhesion surface 24 surrounded by the line 26. If the backing sheet can be stretched elastically, the adhesive surfaces are measured on the undrawn backing sheet before the initial stretch thereof. The garment fastening adhesives may comprise any adhesive or gum used in the art for this purpose, with pressure sensitive adhesives being preferred. Suitable non-extensible adhesives are Century A-305-IV manufactured by Century Adhesives Corporation, Instant Lock 34-2823 manufactured by National Starch Company, 3 Sigma 3153 manufactured by 3 Sigma, and fuller H-2238ZP manufactured by H.B. Fuller Co .. Suitable adhesive fasteners are also described in U.S. Patent No. 4,917,697. In order to maintain water vapor permeability of the backing sheet, according to the present invention, it is important that the fastening adhesive to the panty does not close or plug the entire surface of the side P406 orientation to the garment of the backing sheet. For this purpose, it is possible to use an adhesive in a pattern that only seals a fraction of the surface, so that no more than 80% of the actual surface facing the garment is covered by the adhesive. On the other hand, a 20% coverage with adhesive has been found necessary to provide the benefit of proper attachment to the undergarment relative to the absorbent article. Therefore, preferably, the panty fastening adhesive is applied in intermittent patterns, such as intermittent dots, intermittent strips, patterns of filaments in spiral design or random, to allow the sanitary napkin to be permeable to steam. Water. On the other hand, other types of fasteners can be used instead of the addition of additives. These and other types of fasteners are arranged in patterns similar to those of the adhesives. These fasteners include, without being limited to the following, conventional VELCRO-type crochet material or similar fasteners. The protective side flaps can also have optional fasteners on them for greater safety. The optional fasteners of the protective side flaps may be of any type of fastening material described above. The fasteners P406 helps the protective side flaps remain in place after they have been placed to wrap the edges of the crotch surface. Before use of the absorbent article the panty fastening adhesive is typically protected against contamination and against adhesion to the surface where adhesion is not desired, by means of a protective cover means, for example a release paper coated with silicone, a plastic film or any other cover that can be easily removed. The protective cover means may be provided in one piece or in several pieces, for example to cover the individual areas of adhesive.

Measurement of flexibility or fall The procedure for measuring the flexibility / fall of the absorbent article is as follows: REFERENCE Method ASTM D1388-64: Standard Methods for Test Fabric Rigidity (modified as described below) PRINCIPLE The test is based on the beam principle in P406 cantilever. The distance a strip sample can extend beyond a flat platform is measured before it is bent through an angle of 41.5 degrees. The interaction between the weight of the sample and the stiffness of the sample that is measured as the sample bends or falls due to its own weight, through a given angle, under specific test conditions, is used to calculate the flexibility / fall.

GENERAL COMMENTS The flexibility test is only one way to measure the flexibility of a sample and is believed to be one of the components that users of absorbent articles normally mention as softness. This method of measurement should be as specific as possible to what has been described and should not be confused with the multidirectional flexibility described in US 5,009,653. Although the test of samples in only the longitudinal direction is described, because it is necessary for the invention, it is also possible for a wide variety of exceptionally flexible articles to measure the flexibility in the transverse direction. In general, a sample strip must be tested only once. The two sides of the sample should be tested on different sample strips. By way of P406 similar, the sample strips used in this test must be handled carefully to avoid folds, wrinkles, creases, etc. This test is intended for use on items before they are folded or folded for packaging by the manufacturer . If the sample is placed by the manufacturer in a folded configuration, it should be deployed very gently to be tested. If only folded items are available, the Flexibility / Fall can be approximated by measuring a sample taken from between the fold lines. The test should be used in complete samples, ie with all the layers that have the same shape extending towards the entire sample surface and fully glued together. For each sample four different strips should be measured with the top sheet up and four different strips with the top sheet down. The sample must be measured in the longitudinal direction. It can be seen that for measurements of relatively rigid absorbent articles, even in the longitudinal direction, these can not possibly be obtained because the length of the sample is insufficient to bend by approximately 41.5 degrees.

P406 DEVICE Cantilever Drop Stiffness Tester Type SDL 003B SDL International Obtained from Cari von Gehlen / Germany (Tel .: 02168/2910; Fax: 02168/24570 1 in. Cutter Double edge cutter, 25.4 mm wide width (1 inch) Fourth conditioner A room conditioned at 21.7 ° C-23.9 ° C, 50% ± 2% relative humidity. Talcum powder Zerostat gun To eliminate the static load in the Anti-Static tester and / or tissue. Distributed in (fall) (optional) United States by Dishwasher, Inc., Columbia, MO 65201. Obtainable from Morgan Instruments, Inc., P.O. Box 46442.113 Circle Freeway Dr., Cincinnati, OH 45246. Morgan Catalog No. 70-35-00. Also available from recording stores and photo supply stores. The use of this gun is an approved way to remove the static charges from the test. Never use fabric softeners to remove the static carcass in a drop test. Operate the Anti-static gun according to the manufacturer's instructions.

P406 SAMPLE PREPARATION Samples should be placed in an area of the room that allows maximum air recirculation and a maximum balance between humidity and temperature. 1. Cut 8 samples using a 1-inch-wide cutter. The sample strip has to be cut longitudinally from the center of the absorbent article, and in rectangular form, without the thin canvas. Normally the dimensions of the sample for the measurement are 2.54 cm by 14.0 cm = 35.56 cm2. The samples may be smaller but must comprise absorbent material throughout the entire sample. 2. Remove the release paper and weigh the sample (mg). Round the weight to the nearest 1 mg. 3. Carefully sprinkle the PFA with the minimum amount of talcum sufficient to avoid sticking. Blow off the remaining talc from the sample. 4. Weigh the sample strip with talcum (mg). Round the weight to the nearest 1 mg. 5. For each sample, calculate the base weight of the sample based on the measurement and weight, with and without talc, and calculate the actual surface area of the sample. 6. Discard the sample if the weight increases by more than 2.0 mg / cm2 after adding the talc.

P406 INSTRUMENT OPERATION The drop tester should be placed on a bench directly in front of the operator. It is important that the bank is relatively free of vibrations, that there are no air flows during the measurement and that the bank is free of bursts. The operator can sit or stand in front of the tester while he is using it. Subsequently, the operator has to select his position so that he can observe in the tester mirror and see the front reference line covering the rear reference line. If you see only one of the lines then you are in the correct position for the measurement. The tester should: 1. Remove the sample ramp bar from the sample slot on the top platform of the drop tester. 2. Place the sample strip on the sample slot, so that one end of the strip is exactly level with the vertical edge of the tester. The strip should be placed as close as possible to the rail side of the sample slot, pin not touching it. 3. Place the sample ramp bar on top of the sample strip, so that its edge P406 is aligned with the edge of the sample strip in the tester and so that it touches the side rail. The sample ramp bar should be placed carefully so that the sample is not wrinkled or moving forward. 4. Pull from its free edge and use a very light and soft pressure, move the ramp bar slowly and stably forward with a speed of approximately 1 cm / sec. As the ramp bar moves forward, the sample must move at an equally slow speed. As the ramp bar and sample strip project over the edge of the tester, the sample strip will begin to fold or fall downward. Stop moving the ramp bar at the instant in which the leading edge of the sample strip falls to a level with the reference line of 41.5 °. If the sample has a tendency to twist, take the reference point in the center of its leading edge. Samples that are twisted more than 45 ° can not be measured. Samples can only be measured if the length of the sample is at least 0.5 cm longer than the hanging length. For samples that can not be measured, the hanging length can be measured only if a sufficiently long strip can be obtained.

P406 at least 0.5 cm longer than the hanging length. 5. Mark the hanging length on the upper part of the sample (hanging length: distance from the starting point of the movement to the point where the sample is bent through 41.5 °). 6. Measuring the hanging length in cm with a ruler. Read the hanging length up to the nearest 1 mm.

CALCULATION The equation used to express the Flexibility / Fall according to the present invention is the following: G = WL3 where G is equal to Flexibility / Fall, W is the base weight of the sample including talc in milligrams / cm2, and L is the length of the hanging portion in cm. The result is expressed in milligrams x cm or grams x cm.

Thickness measurement Thickness should always be measured in the thickest possible place, usually in the center of the absorbent article. For convenience, the measurement is made in the absorbent article including any protective cover means present. The article must be reconditioned to P406 a humidity of 50% and 23 ° C for two hours, within its normal packaging and remove no more than five minutes before measurement. The thickness is measured with a micrometer gauge that has a scale of 0 to 30 mm and is capable of a tolerance of plus / minus 0.5 mm. The gauge must not be spring-loaded and must have a leg that moves backwards due to gravity. The leg of a micrometer has a diameter of 40 mm and is loaded with a weight of 80 grams. The measurement is taken between 5 and 10 seconds after the leg has been lowered to remain in contact with the absorbent article. The measurement should be taken as many times as is sufficient to allow statistical analysis to determine the average thickness within a sigma of plus / minus 0.1 mm. A detailed description of the thickness measurement can be found in U.S. Patent No. 5,009,653.

P406

Claims (21)

1. CLAIMS Z 1. An absorbent and flexible article that is used in an undergarment, the article does not comprise protective side flaps, the article comprises a backsheet that has a facing surface toward the garment and the article comprises an absorbent core; the garment-facing surface comprises an adhesive for adhering the article to the garment, the adhesive has a real surface of adhesive and the adhesive defines a theoretical adhesion surface within an endless line which is the shortest surrounding line of the adhesive without extending beyond the periphery of the orientation surface towards the garment; the backing sheet is permeable to water vapor and comprises a layer permeable to water vapor but impermeable to liquid; the article is characterized in that: the proportion of surfaces between the actual adhesive surface and the surface facing the garment is in the range of 0.2 to 0.8; the proportion of surfaces between the theoretical adhesion surface and the surface of orientation towards the garment is in the range of 0.6 to 1.0 for articles that do not have lateral protective fins; and the article has a flexibility of 1300 mg x cm to 5000 mg x cm, measured according to modified ASTM method D1388 2. An absorbent article according to claim 1, wherein the flexibility is in the range of 2000 mg x cm to 3500 mg x cm. 3. An absorbent article according to claim 2, wherein the flexibility is in the range of 2000 mg x cm to 3000 mg x cm. An absorbent article according to claim 1, wherein the ratio of surfaces between the theoretical adhesion surface and the garment facing surface is in the range of 0.85 to 1.0 for articles that do not have protective side flaps. An absorbent article according to claim 1, wherein the maximum thickness of the article along a perpendicular axis of the garment facing surface is less than 3 mm. An absorbent article according to claim 5, wherein the maximum thickness of the article along an axis perpendicular to the garment-facing surface is in the range of 0.5 mm to 1.5 mm. An absorbent article according to claim 1, wherein the article is elastically stretchable at least in a direction parallel to the garment facing surface. An absorbent article according to claim 7, wherein the article is elastically stretchable in at least two directions not parallel to each other, but both are parallel to the garment facing surface. 9. An absorbent article according to claim 1, wherein the backsheet comprises a vapor permeable layer of water and at least one additional layer. An absorbent article according to claim 9, wherein the additional layer is a layer of fibrous fabric and the backing sheet is oriented so that its garment facing side is provided by the fibrous fabric layer. 11. An absorbent and flexible article that is used in an undergarment, the article comprises protective side flaps, the article comprises a backsheet that has a facing surface toward the garment and the article comprises an absorbent core; the garment-facing surface comprises an adhesive for adhering the article to the garment, the adhesive has a real surface of adhesive and the adhesive defines a theoretical adhesion surface within an endless line which is the shortest surrounding line of the adhesive without extending beyond the periphery of the orientation surface towards the garment; the backing sheet is permeable to water vapor and comprises a layer permeable to water vapor but impermeable to liquid; the article is characterized in that: the proportion of surface between the actual adhesive surface and the surface facing the garment is in the range of 0.2 to 0.8; the proportion of surface between the theoretical adhesion surface and the surface of orientation towards the garment is in the range of 0.5 to 1.0 for articles that do not have lateral protective fins; and the article has a flexibility of 1300 mg x cm a 5000 mg x cm, measured according to modified ASTM method D1388 12. An absorbent article according to claim 10, wherein the flexibility is in the range of 2000 mg x cm to 3500 mg x cm. 13. An absorbent article according to claim 12, wherein the flexibility is in the range of 2000 mg x cm to 3000 mg x cm. P406 14. An absorbent article according to claim 11, wherein the proportion of surfaces between the theoretical adhesion surface and the garment facing surface is in the range of 0.7 to 0.9 for articles with protective side flaps. 15. An absorbent article according to claim 11, wherein the maximum thickness of the article along an axis perpendicular to the garment facing surface is less than 3 mm. 16. An absorbent article according to claim 15, wherein the maximum thickness of the article along an axis perpendicular to the garment facing surface is in the range of 0.5 mm to 1.5 m. 17. An absorbent article according to claim 11, wherein the article is elastically stretchable at least in a direction parallel to the garment facing surface. 18. An absorbent article according to claim 17, wherein the article is elastically stretchable in at least two directions not parallel to each other, but both are parallel to the garment facing surface. 19. An absorbent article according to claim 11, wherein the backsheet comprises P406 a layer permeable to water vapor and at least one additional layer. An absorbent article according to claim 19, wherein the additional layer is a layer of fibrous fabric and the backing sheet is oriented such that its garment facing side is provided by the fibrous fabric layer. 21. An absorbent article according to any of the preceding claims wherein the article is a pantiprotector. P406 RESOLUTION OF THE INVENTION The present invention relates to absorbent articles permeable to water vapor, such as, for example, sanitary napkins, pantiliners, and incontinence pads that adhere by means of adhesives (22) to an undergarment during use. More particularly, the present invention relates to articles having a backsheet permeable to water vapor and having a flexibility in the longitudinal direction and, also, that in particular can adhere well to the undergarment in order to provide improved comfort for the user of the article. P406