MXPA97002540A - Flexible absorbent articles and its fixation to interior garments - Google Patents

Abstract

The present invention relates to absorbent articles (10) such as sanitary napkins, linings for panties, and incontinence pads, which adhere to an undergarment during use. More particularly, the present invention relates to articles (10) having a flexibility in a longitudinal direction that provides improved comfort to the wearer of the article.

Description

FLEXIBLE ABSORBING ARTICLES AND THEIR FIXATION TO INTERIOR CLOTHES FIELD OF THE INVENTION The present invention relates to absorbent articles such as sanitary napkins, linings for panties and incontinence pads, which are adhered to an undergarment during use. More particularly, the present invention relates to articles having a flexibility in a longitudinal direction that provides comfort to the user of the article.

BACKGROUND OF THE INVENTION Absorbent articles such as sanitary napkins, panty liners and incontinence pads are typically used in the region of crotch of an undergarment, and are attached to the undergarment by means of a fastening adhesive of the pantyhose, so-called. In order to be comfortable to the user, these products need to be flexible. I know that the greater flexibility of an absorbent product will be the one least noticed by the user. From here, it provides comfort by more closely resembling the situation when said absorbent product is not used. Flexibility can be easily achieved by reducing the amount of material in an absorbent product, or by replacing the rigid / inflexible components with more flexible components. However, it has been recognized for a long time that extreme flexibility can decrease the absorbent performance of these articles, for example by an insufficient amount of absorbent material or by bulk or densification of the absorbent material during use. Also, a product that is too flexible can be difficult for the user to handle when it is attached to the undergarment. The problem of excess flexibility in a product due to a low amount of inflexible material has been enshrined, for example, in U.S. Patent 4,217,901, where the stiffness of an absorbent product is particularly required in order to provide the satisfactory performance of the product. This reference to the state of the art accepts the implications of comfort caused by its rigidity requirement. It has now been found that the comfort of the absorbent products can be drastically improved when high flexibility is provided in the longitudinal direction, or low stiffness in combination with a particular configuration of panty fastening adhesive, to maintain the flat product in relation to the user's undergarment. Then, flexibility becomes limited only by the requirements of the material (for example, to provide sufficient absorbent performance), and by the manipulation of the requirements of the absorbent product. Therefore, it is an object of the present invention to provide sanitary napkins with improved flexibility without the previously experienced disadvantages. In particular, a high degree of flexibility is achieved with the absence of bulging problems without major handling difficulties, by the present invention. These and other objects of the present invention will be more apparent when considered with reference to the following description.

BRIEF DESCRIPTION OF THE INVENTION The present invention provides an absorbent product such as a sanitary napkin, an incontinence pad, and particularly a panty liner for use in an undergarment. The absorbent product has a garment facing surface comprising an adhesive for adhering the product to the garment. Optionally, the product may comprise protective side flaps, which are bent during use around the side edges in the crotch region of the garment, to improve protection against staining of the garment. The absorbent product also comprises the other typical components of these products, namely an absorbent core and a user-facing surface, permeable to the liquid, which is preferably provided by a liquid-permeable top sheet. It is also typical for the absorbent product to comprise a waterproof backsheet _-. ü liquid, which usually provides the surface that gives towards the garment of the absorbent product. If the upper sheet and the back sheet are present, the absorbent core is enclosed by them in the wearer and on the side of the garment, respectively. 5 The adhesive can cover all, part or several different parts of the surface that it gives towards the garment. The adhesive may be provided covering the total surface area or it may be in a filamentary manner, which is random or in a defined design. The total of all the adhesive on the surface facing the garment of the absorbent product defines the actual adhesive surface. Further, a theoretical adhesion surface is given by the periphery of a continuous line, which is the shortest circumscribing line of the adhesive, without extending beyond the periphery of the surface facing the garment by itself .

It is provided as a minimum half of the surface that gives towards the garment with the adhesive to fix the product to the undergarment. The absorbent product according to the present invention has a surface ratio of the theoretical surface of adhesion to the surface that gives the garment on the scale of 0.6 to 1, preferably 0.85 to 1 for products without the protective side flaps, and on a scale of 0.5 to 1, preferably from 0.7 to 0.9 for products with protective lateral fins. In a modality Preferred, the theoretical adhesion surface is substantially coextensive with the actual surface covered by the adhesive. In order to understand the benefits of the present invention, the absorbent products as a whole need to provide exceptional flexible capacity. The The flexibility is measured by the modified method D1388 ASTM as described hereinafter, in the longitudinal direction. The expression "flexibility" is also referred to as "drapability" due to the particular method. It should be understood that rigidity is characteristic of behavior opposite of a material. The flexibility should be in the range of 1300 to 3500, preferably 1300 to 3000, more preferably 2000 to 2700, mgr x cm. These flexibility values in combination with the surface ratio indicated above, provide the exceptional wearing comfort without the problems of staining and absorbent performance due to bulging or densification of the absorbent material, and still allows the user to fix the product to the undergarment without undue effort. According to the present invention, the flexibility in the longitudinal direction is measured because this is the most easily measurable value. In principle, transverse flexibility should also be used, possibly to different values. Due to the small extent of the products in the transverse direction, it is not usually possible to measure flexibility in this direction appropriately. The thickness of a preferred embodiment of the present invention, specifically for panty liners is less than 3 mm and even more preferably in the 0.5 to 1.5 mm scale, according to the thickness measurement method described hereinafter. Particularly useful is the combination of the width of the fastening adhesive of the panty and the flexibility , appropriate, in the context of the stretchable absorbent products. Absorbent articles that are stretchable in one direction and more for absorbent products that are stretchable in two (or all) directions, are inherently flexible. Stretching by itself provides an improvement for comfort, such that absorbent products that combine stretchability with the present invention are particularly desirable.

Particularly useful are the absorbent-stretchable products having the stretch characteristics described in the 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 this application. For products that are stretchable, limitations on flexibility are less stringent. In particular, according to the present invention, the stretchable absorbent products can have a flexibility of 5000 mgr x cm at t) 1300 mgr x cm, with an actual adhesive surface of at least % of the surface facing the garment, for panty liners without protective side flaps the adhesive that secures the panty liner to the garment may be provided as a continuous strip that closely follows the periphery of the lining for panty, and which leaves a substantial portion of the pant liner inside the continuous strip, free of adhesive.

BRIEF DESCRIPTION OF THE DRAWINGS 0 Figure 1 shows a plan view of the surface facing the garment of a pant liner without the protective side flaps, according to the present invention. Figure 2 shows the surface facing the garment of a sanitary napkin having side protective flaps, according to an alternate embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described with reference to pant lining. However, it is equally well applicable to sanitary napkins or products for _ £. adult incontinence, which are used in an undergarment and are attached to the undergarment during the use of the absorbent product. According to the present invention, the absorbent products typically comprise three components main: a liquid-permeable upper sheet, a liquid-impermeable back or back sheet and an absorbent core. In the absorbent core is enclosed by the leaf , "" and the top sheet, and the product is used such that the exposed surface of the top sheet faces the user of the absorbent product, while the exposed surface of the backsheet gives towards the garment to which the product is attached by means of fixing means for fastening the panty. This is typically an adhesive but can also be a mechanical fixation. The present invention is interested in the flexibility of the product. The degree of flexibility is determined by the selection of materials for the components of the product as mentioned above, and their respective amounts. It will be apparent to those skilled in the art that, to achieve flexibility according to the present invention, the selection of the type and amount of raw material has to be balanced with other desired characteristics of the absorbent product, such as for example the absorbent capacity , absorption speed and surface dryness on the outside of the upper sheet during use. Therefore, the following description of the typical materials of the main components of the absorbent product will make it possible to provide an almost infinite number of product variants within and outside the limitations of the flexibility according to the present invention. Whether or not an absorbent product satisfies the flexibility requirements of the present invention, then it can be analyzed by simple measurement according to the method described below. Absorbent articles according to a preferred embodiment of the present invention are elastically stretchable. As used herein, the term "elastically stretchable" means that when the stretching forces are removed, the article will tend to return to its non-stretched or unstretched (or "original") dimension, however, it does not need to return entirely to Its unstretched dimensions If the absorbent article is stretchable elastically, it can be stretchable in one or two directions (which are not parallel) 5 within the product plane, ie parallel to the surface facing the garment The materials for elastically stretchable articles may be elastically stretchable per se, or be treated to provide stretch capacity In particular, elastic backsheet material, elastic sheet material, filamentary materials combined with elastic threads, filaments or wefts can also be used in this context, such as shirring, folding or ring rolling of the materials. It is known in the art the appropriate material and methods, and for example are described in detail in the application of the United States 08/192240 of February 4, 1994, specifically referred to in order to facilitate the selection of materials if they are made stretchable absorbent articles of according to the present invention.

In the following, non-limiting embodiments of the main elements of the absorbent product that can be used in stretchable or non-stretchable designs are described.

ABSORBENT NUCLEUS The absorbent core typically includes the following components: (a) a primary fluid distribution layer, optionally; (b) a secondary fluid distribution layer, optional, but preferable; (c) a fluid storage layer; (d) an optional fibrous layer ("dedusting") underlying the storage layer; and (e) other optional components. to. Primary layer of Fluid Distribution An optional component of the absorbent cores according to the present invention is the primary fluid distribution layer. This primary distribution layer is typically below the top sheet and is in fluid communication with it. The top sheet transfers the obtained menstrual fluid to this primary distribution layer for the final distribution to the storage layer. This transfer of fluid through the primary distribution layer not only occurs in the thickness, but also along the length and width directions of the absorbent product. b. Optional Secondary Fluid Distribution Layer Also the preferred but optional component of the absorbent cores according to the present invention is a secondary layer of fluid distribution. This secondary layer of fluid distribution is typically below the primary distribution layer and is in fluid communication with it. The purpose of this secondary distribution layer is to easily obtain the menstrual fluid from the primary distribution layer and transfer it rapidly to the underlying storage layer. This helps the fluid capacity of the underlying storage layer to be fully utilized. c. Fluid Storage Layer Placed in fluid communication with, and typically underlying the primary and secondary distribution layers, is a fluid storage layer comprising certain gelling absorbent materials and / or other absorbent materials, which can form a carrier matrix for the absorbent materials of gelation. The gelling absorbent materials are usually referred to as "hydrogels", "superabsorbent" materials, "hydrocolloids". The absorbent gelling materials are those materials which, upon contact with aqueous fluids, especially aqueous body fluids, imbibe said liquids and thus form hydrogels. These absorbent gelling materials are typically capable of absorbing large quantities of aqueous body fluids, and are further capable of retaining said absorbed fluids under moderate pressure. These absorbent gelling materials are also typically in the form of discrete, non-fibrous particles. This fluid storage layer may comprise only absorbent gelling materials, or these may be homogeneously or non-homogeneously dispersed. '-.-' gelling absorbent materials in an appropriate carrier material, or may comprise only a carrier absorbent material. Suitable carrier materials include cellulose fibers, in the form of a sponge, tissue or paper as is conventionally used in absorbent cores. HE may also use modified cellulose fibers, such as hardened cellulose fibers. Also, synthetic fibers can be used and include those made of cellulose acetate, polyvinyl fluoride, polyvinyldene chloride, acrylics (such as Orion), polyvinyl acetate, polyvinyl alcohol non-soluble, polyethylene, polypropylene, polyamides (such as nylon), polyesters, two-component fibers, three-component fibers, mixtures thereof and the like. Preferred synthetic fibers have a denier of about 3 denier per filament at about 25 denier per filament, more preferably from about one denier of 5 per filament to about one denier of 16 per filament. Also preferably, the surfaces of the fiber are hydrophilic or are treated to be hydrophilic. The storage layer may also include filling materials, such as phonolite, diatomaceous earth, Vermiculite, etc., which reduce the problems of rewetting. If it is dispersed in a non-homogeneous manner in a carrier material, the storage layer can be locally homogeneous, that is, have a distribution gradient in one or more directions within the dimensions of the storage layer. Also, the inhomogeneous distribution can be referred to laminates of carrier materials that partially or completely enclose the gelling absorbent materials. Preferably, the storage layer comprises from about 15 to 100% absorbent absorbent materials, and from 0 to about 85% carrier material. Preferably, the storage layer comprises from about 30 to 100%, most preferably from about 60 to 100% of gelling absorbent materials, and from 0 to about 70%, most preferably from 0 to about 40%, of the carrier material. The gelling absorbent materials suitable for use herein will very often comprise a polymeric gelling material, substantially insoluble in water, partially neutralized, lightly crosslinked. This material forms a hydrogel upon contact with water. Said polymeric materials can be prepared from polymerizable, unsaturated, acid-containing monomers. Suitable unsaturated acidic monomers for use in the preparation of the polymeric gelling absorbent material used in this invention include those listed in U.S. Patent 4,654,039 and reissued as RE 32,649. The preferred monomers They include acrylic acid, methacrylic acid, and 2-acrylamido-2-methyl propanic acid. The acrylic acid itself is especially preferred for the preparation of the polymeric gelling material. The polymer component formed of acid-containing, unsaturated monomers, can be grafted onto other types of polymer portions, such as starch or cellulose. Especially preferred are polyacrylate grafted starch materials of this type. Preferred gelling, polymeric, gelling materials that can be prepared from types Conventional monomers include hydrolyzed starch-acrylonitrile graft copolymer, starch-polyacrylate graft copolymer, polyacrylates, maleic anhydride-based copolymers and combinations thereof. Polyacrylates and polyacrylate grafted starch are especially preferred. Although these absorbent gelling materials are typically in particulate form, it is also contemplated that the absorbent gelling materials may be in the form of macrostructures such as fibers, sheets or strips. Typically, these macrostructures are prepared by forming the particulate gelling absorbent material into an aggregate, treating the aggregate material with a crosslinking agent, compacting the treated aggregate to densify it and forming a coherent mass, and then curing the compacted aggregate to cause that the crosslinking agent reacts with the absorbent gelling material, in particles, to form an absorbent, mixed porous macrostructure. Said absorbent, porous macrostructures are described, for example, in U.S. Patent 5,102,597. d. Optional Fiber Coat ("Dustproof") An optional component for inclusion in the absorbent cores 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. Indeed, in those cases where the gelling absorbent material is in the form of macrostructures such as fibers, sheets or strips, this fibrous "dusting" layer need not be included. However, because this "dedusting" layer provides some additional fluid handling capabilities such as rapid impregnation of the fluid along the length of the pad, its inclusion is typically preferred in absorbent cores according to the present invention. and. Other Optional Components The absorbent cores according to the present invention can include other optional components normally present in absorbent webs. For example, a reinforcing fabric may be placed within the respective layers, or between the respective layers, of the absorbent cores. Said reinforcing sheets should be of such configuration as they do not form interfacial barriers for fluid transfer, especially if they are placed between the respective layers of the absorbent core. Given the structural integrity "that usually occurs as a result of thermal bonding, usually the reinforcement canvases are not required by the absorbent structures according to the present invention.

Another component that can be included in the absorbent core according to the present invention, and preferably is provided close to or as part of the primary or secondary fluid distribution layer are the odor control agents.

Typically activated carbon coated with or in addition to other odor control agents, in particular suitable zeolite or clay materials, are optionally incorporated into the absorbent core. These components can be incorporated in any desired way, but j are often included. as discrete, non-fibrous particles.

TOP SHEET The upper sheet is deformable, soft feeling and non-irritating to the wearer's skin. As indicated above, the top sheet can also be stretchable elastically in one or two directions. In addition, the top sheet is permeable to fluids allowing fluids (eg, menstruation and / or urine) easily penetrate through its 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 formed with openings, apertured plastic films, and hydroformed thermoplastic films, porous foams, cross-linked foams. , reticulated thermoplastic films, and thermoplastic films. Suitable woven and nonwoven materials may be composed of natural fibers (eg, wood or cotton fibers), synthetic natural fibers (e.g., polymeric fibers, such as polyester fibers, polypropylene fibers, and fibers). polyethylene), or a combination of natural and synthetic fibers. Preferred top sheets for use in the present invention are selected from non-woven top sheets , -c) of raised floor and top sheets of film formed with openings. Especially preferred are films formed with openings for the topsheet, since these are permeable to body exudates and, still not absorbent and have a reduced tendency to allow liquids pass through and re-moisten the user's skin. In this way, the surface of the formed film that is in contact with the body remains dry, thereby reducing "" '' the spottand creata more comfortable feelfor the user. Films formed with apertures, suitable, are described in US Pat. No. 3,929,135; U.S. Patent 4,324,426; U.S. Patent 4,342,314; U.S. Patent 4,463,045; and United States Patent 5,006,394. Top sheets of formed film with particularly preferred micro apertures are described in U.S. Patent 4,609,518 and U.S. Patent 4,629,643. The preferred top sheet for the present invention is the formed film described in one or more of the above patents and marketed in sanitary napkins as "DRI-WEAVE", by The Procter & Gamble Company of Cincinnati. The upper sheets that do not have a homogeneous distribution of liquid passageways are also contemplated by the present invention, but only a part of the upper sheet comprises liquid passageways. Typically, said top sheets would have the conduits of -., < -) oriented liquid passage, such that these result in a centrally permeable upper sheet and peripherally impermeable for liquids. The body surface of the formed film topsheet can be hydrophilic to help the liquid to be transferred through the topsheet faster 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 U.S. Patent Application Serial No. 07 / 794,745, filed on November 19, 1991 by Azis and others. Alternatively, the body surface of the topsheet can be rendered hydrophilic by treatit with a surfactant such as is described in the aforementioned U.S. Patent 4,950,254.

BACK SHEET The backsheet prevents the exudates absorbed and contained in the absorbent core from moistenthe articles that are in contact with the sanitary napkin, such as pants, pajamas and underwear. The backsheet is 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. The back sheet needs to be docile and will easily conform to the general shape and contour of the human body. Also, the backsheet may have characteristics that allow it to stretch elastically in one or two directions. The backsheet may comprise a woven or non-woven material, polymeric films, such as polyethylene or polypropylene thermoplastic films, or mixed materials such as nonwoven material coated with a film. Preferably, the backsheet is a thin plastic film, such as a polyethylene film hava thickness of about 0.012 mm to about 0.051 mm. Exemplary polyethylene films are manufactured by Clopay Corporation of Cincinnati, Ohio, under the designation P18-1401 and by Ethyl Corporation, Visqueen Division, of Terre Haute, Indiana, under the designation XP-39385. The backsheet is preferably engraved and / or finished in matt to provide an appearance more of the type of fabric. In addition, the backsheet can allow vapors to escape from the absorbent core (that is, be breathable), while still preventthe exudates pass through the back sheet.

THE ADHESIVE TO HOLD THE TROUSER Typically, the back sheet forms the surface f i that faces the garment on which the panty fastenadhesive is placed. Accordto the present invention, it is important that the ratio of the theoretical surface of adhesion to the actual surface facthe garment is within the scale accordto the claims of the present invention. The theoretical adhesion surface is defined by the surface area within the continuous line as narrow as possible circumscribthe fastenadhesive of the panty, however without extending beyond the periphery of the surface facing the garment. In addition, the actual adhesive surface needs to be at least 50% of the surface facing the garment, or at least 20% for the stretchable absorbent articles. If there is, for example, a rectangular adhesive area on the If the surface facing the garment is identical, then the theoretical adhesion surface and the actual adhesive surface are identical, this can be seen in Figure 1 where the adhesive 22 is indicated by the shadow made by lines. The surrounding line 26 results in a theoretical adhesion surface 24, 5 identical to the surface covered by the adhesive 22. For the absorbent products having protective side flaps, Figure 2 shows that the three adhesive areas 22 are smaller in area surface than the theoretical adhesion surface 24 surrounded by line 26. If the back sheet is / - _: elastically stretchable U, the adhesive surfaces on the backsheet are measured without stretching before the initial stretch thereof. The fastening adhesives of the panty can comprise any adhesive or glue used in the art for such purposes, 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 the 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 4,917,697. Extendable adhesives suitable for use as panty fasteners include extendable adhesives, per se, and combinations of extendable adhesive backsheet. Any of the extensible adhesives known in the art can be used. Suitable combinations of extensible adhesive / backsheet are for example non-extensible adhesives used in a backsheet material such as 3 Sigma 2474 available from Anchor Continental, Inc., Division 3 Sigma, Covington, Ohio; elastically stretchable adhesive films such as Findley adhesive 198-338, or an elastically stretchable adhesive film from Minnesota Mining and Manufacturing Company of St. Paul, Minnesota; or powdered adhesives such as 3M adhesive 1442 in a low modulus elastic film. Other suitable panty fastening adhesives are shown in International Patent Publication TCP No. WO 92/04000, WO 93/01783 and WO 93/01785. It should be understood that if it is desired to make the component that forms the surface facing the garment of the sanitary napkin (and any of the underlying components) extendable in the wearer's panties, the particular configuration of the adhesive that can be used It depends on whether extensible or non-extensible adhesives are used. The portion of the sanitary napkin on which the extendable adhesives are located will be extensible. Sanitary napkins containing non-extensible adhesives will typically only be able to spread between non-stretch adhesive patches. Therefore, if non-extensible adhesives are used, these are preferably applied in intermittent patterns such as for example intermittent spots, intermittent strips, random or designed patterns of filaments, to allow the sanitary towel to extend. If, on the other hand, the adhesive is extensible, the adhesive can be applied in continuous or intermittent patterns. In addition, other types of fasteners can be used instead of, or in addition to, the adhesives. These other types of fasteners are arranged in patterns similar to those of the adhesives. These fasteners include, but are not limited to, the conventional VELCRO hook material or similar fasteners, the protective side flaps may have optional fasteners on them for additional safety, and the optional side flap fasteners may provide additional protection. to be any of the types of fastening materials hereinabove. The fasteners assist the protective side flaps in keeping them in position after they are wrapped around the edges of the crotch surface of the protective side flaps. Before the use of the absorbent article, the panty fastening adhesive is typically protected from contamination and from sticking to any surface where this is not desired, by means of a protective cover means such as a paper coated with release silicone, a plastic film or any other easily removable cover. The protective cover means can be provided as a single piece or in a multitude of pieces, for example to cover the individual adhesive areas.

Measurement of flexibility or drapeability The procedure for measuring the flexibility / drapability of the absorbent article is as follows: ^ REFERENCE Method B1388-64 ASTM; Standard methods to test the firmness of the fabrics (modified as described here).

PRINCIPLE 5 This test was based on the beam-beam principle. The distance of a strip from a sample that can be extended beyond a flat platform before it is curved through an angle of 41.5 ° is measured. The interaction between the weight of the sample and the firmness of the sample is measured as the sample is curved or draped under its own weight through a given angle under specific test conditions, it is used to calculate the Flexibility / Drapeability.

GENERAL COMMENTS 5 The flexibility test is only one way to measure the flexibility of the sample, and it is believed to be one of the components that users of absorbent articles often refer to as softness. This measurement method should be followed as closely as possible, and should not be confused with the multidirectional flexibility 5 described in US 5,009,653. Even so, the testing of the samples in only the longitudinal direction is described, and necessary for the present invention is also possible for very broad or exceptionally flexible products for measuring the flexibility in the transverse direction. -J In general, a simple sample strip must be tested only once. The two sides of the sample must be tested on different sample strips. Also, the sample strips to be used in this test must be carefully managed to prevent bends, wrinkles, 5 bends, etc. It is intended that this test be used on the products before they have been folded or folded for packaging by the manufacturer. If the sample is placed by the manufacturer in a bent configuration, it should unfold smoothly for the test. If only 0 folded products are available, flexibility / drapeability can be approximated by measuring a sample taken from between the folded lines. The test must be used on complete samples, that is, with all the layers that have the same shape that extend to the entire surface of the sample and are totally glued together. For each sample, four different strips should be measured with the top sheet facing up and four different strips with the top sheet facing down. Samples should be measured in the longitudinal direction. It is noted that measurements for the relative rigidity of the absorbent articles even in the longitudinal direction may not be obtainable because the length of the sample to fold by 41.5 ° is insufficient.

APPARATUS Wall Beam Strength Tester type SDL 003B SDL International, Retrieved from Cari Von Gehlen / Germany (Telephone 02168/2910; Fax 01268/24570). One-inch cutter with double-edge cutter, 25.4 mm wide (1 inch) Environmental conditions An environment conditioned at 21.7 ° C - 23.9 ° C, 50 ± 2% Relative Humidity. Talcum Powder Anti-static Zerostat To eliminate the static charge in the gun tester (optional) of drape and / or tissue. Distributed in the U.S.A. by Disc asher, Inc., Columbia, MO 65201. Available from Morgan Instruments, Inc., PO Box 46442, 113 Circle Freeway Drive, Cincinnati, OH 45246. Morgan Catalog No. 70-35-00. Also available from record stores and photo supply stores. The use of this gun is an approved way to remove static charges for this test. Never use fabric softener to remove static charge from a drape test. The antistatic gun operates according to the manufacturer's instructions.

PREPARATION OF THE SAMPLE The samples should be placed in an area of the room that allows a maximum recirculation of the air and maximizes the balance with the humidity and temperature conditions. 1. Cut 8 samples using a 1 inch (2.54cm) wide cutter. The sample strip has to be cut longitudinally from the center of the absorbent product so that it is rectangular without bending. The usual dimensions of the sample for the measurements are 2.54 cm x 14.0 cm = 35.56 cm2. The samples may be shorter but must comprise absorbent material throughout. 2. Remove the release paper and weigh the sample (mg). Round the weight to 1 mg closer. 3. Carefully sprinkle the PFA with the minimum amount of talc, enough to avoid sticking. Blow the rest of talc from the sample. 4. Weigh the sample strip with talcum (mg). Round the weight to 1 mg closer.

. For each sample, calculate the base weight of the sample based on the weight measurement with and without talc, and the actual surface area of the sample. 6. Discard the sample if its weight increased more than 2.0 mg / cm2, after adding talc.

INSTRUMENT OPERATION The drape tester should be placed on a bench directly in front of the operator. It is important that the bank is free of vibrations, that there is no air flow during the measurement, and that the bank is free of drafts. The operator may be standing or sitting in front of the tester while it is being used. Subsequently, the operator has to choose his position in such a way that he observes in the mirror of the tester that he sees the frontal line of reference covering the posterior line of reference. The tester should: 1. Remove the sample slide bar from the sample slot on the top platform of the drape tester. 2. Place one of the sample strips over the sample slot so that one end of the sample strip is exactly flush with the vertical edge of the tester.

The strip should be placed as close as possible to the side rail of the sample slot but not touching it. 3. Place the sample slide bar on top of the sample strip so that its front edge is aligned with the edge of the sample strip in the tester, so that it touches the side rail. The sample slide bar should be carefully positioned so that the sample does not wrinkle or move forward. 4. Pull from its free edge and use gentle, very light pressure, move the slide bar slowly and smoothly, forward with a speed of approximately 1 cm / second. As the sample slide bar moves forward, the sample must move at a slow, equal speed. As the slide bar and sample strip project over the edge of the tester, the sample strip will begin to fold, or drape down. Stop the movement of the sliding bar instantly when the leading edge of the sample strip falls level with the reference line of 41.5o- If the sample has a tendency to twist, take the reference point at the center of its edge principal . Samples that bend more than 45 ° can not be measured. Only samples can be measured if the length of the sample is at least 0.5 cm longer than the protruding length. For non-measurable samples, the protruding length can be measured only if a sufficiently long strip can be obtained that is at least 0.5 cm longer than the protruding length.

. Mark the protruding length at the top of the sample (protruding length: distance from the starting point of the movement to the point where the sample folds at 41.5 °). 6. Measure the protruding length in centimeters with a ruler. Read the protruding length to 1 mm closer.

CALCULATIONS The equation used to express the Flexibility / Drapeability according to the present invention is as follows: G = W L3 where G is equal to Flexibility / Drapeability, W is the basis weight of the sample, including talc, in milligrams / cm2, and L is the length of the projection in cm. The results are expressed in milligrams -cm or grams -cm.

Thickness measurement The thickness should always be measured in the thickest possible place, usually in the center of the absorbent article. For convenience, the measurement is conducted on the absorbent article, including on any present protective covering means. The product must be reconditioned at 50% humidity and 23 ° C for two hours, within its usual package and removed no more than five minutes before the measurement. The thickness is measured with a micrometric meter that has a scale of 0 to 30 mm, and capable of more less 0.5 mm of tolerance. The meter should not be loaded with a spring and must have a foot that moves down by gravity. The foot of the micrometer has a diameter of 40 mm and is loaded with 80 grams of weight. The measurement is taken between 5 and 10 seconds after the foot has been lowered to contact the absorbent article. The measurements should be taken frequently enough to allow statistical analysis to determine the average thickness within a sigma of plus minus 0.1 mm. A detailed description of thickness measurements can also be found in U.S. Patent 5,009,653.

Claims (8)

1. A flexible absorbent product for use in an undergarment, said product optionally comprising 5 protective side flaps, said product comprising a surface facing the garment, said surface facing the garment comprising an adhesive to adhere said product to said undergarment, said adhesive having a real adhesive surface and defining said adhesive t) adhesive a theoretical surface of adhesion within a continuous line which is the shortest line circumscribing the adhesive without extending beyond the periphery of the surface facing the garment, said product being characterized by the combination of: The surface ratio of said actual adhesive surface to said surface facing the garment is at least 0.5; the surface of said theoretical surface of adhesion to said surface that gives towards the garment is in the scale of 20 0.6 to 1.0, for products without said lateral fins of protection, and in the scale of 0.5 to 1.0 for products with said lateral fins of protection; and said product has a flexibility of 1300 mg x 25 cm to 3500 mg x cm, measured according to the ASTM D1388 modification.

2. An absorbent product according to claim 1, further characterized in that said theoretical adhesion surface is substantially coextensive with the actual adhesive surface.

3. An absorbent product according to any of the preceding claims, further characterized in that said flexibility is in the range of 1300 mg x cm to 3000 mg x cm.

4. An absorbent product according to any of the preceding claims, further characterized by "that said flexibility is in the range of 2000 mg x cm to 2700 mg x cm. An absorbent product according to any of the preceding claims, further characterized in that said surface ratio of the theoretical surface of adhesion to said surface facing the garment is in the range of 0.85 to 1.0 for products without said lateral fins of protection, and in the scale of 0.7 to 0.9 for products with said lateral protection fins. 6. An absorbent product according to any of the preceding claims, further characterized in that the maximum thickness of said product along an axis perpendicular to said surface facing the garment is less than 3 mm, preferably in the scale from 0.5 mm to 1.5 mm. 7. An absorbent product according to any of the preceding claims, further characterized in that said product does not have side protective flaps and said surface ratio is 1. 8. An absorbent product according to any of the preceding claims, further characterized in that said product is a lining for panties. ABSTRACT The present invention relates to absorbent articles (10) such as sanitary napkins, linings for panties, and incontinence pads, which adhere to an undergarment during use. More particularly, the present invention relates to articles (10) having a flexibility in a longitudinal direction that provides improved comfort to the wearer of the article.