CZ287970B6 - Flexible absorption article - Google Patents

Abstract

In the present invention there is disclosed a flexible absorption article used underneath underwear and optionally containing protective side flaps comprising a back layer with a surface turned toward the underwear and an absorption core, whereby the surface turned toward the underwear comprises adhesive (22) for adhesion of the article to the underwear, where the adhesive (22) actual adhesive surface and theoretical adhesive surface (24) are inside an infinite line that is the shortest terminating line of the adhesive surface, which does not overlap the circumference if the surface turned toward the underwear and whereby the back layer is permeable to water vapor and comprises a layer that is impervious to a liquid but permeable to water vapor. Ratio of the actual adhesive surface to the surface turned toward the underwear is within the range of 0.2 do 0.8, ratio of the theoretical adhesive surface (24) to the surface turned toward the underwear is within the range of 0.6 do 1.0 in the article with protective side flaps and the article elasticity ranges between 1300 to 5000 mg x cm, measured according to ASTM D1388 procedure.

Description

Flexible absorbent article

Technical field

The present invention relates to a flexible absorbent article permeable to water vapor, for example sanitary napkins, trousers and incontinent pads, which in use adhere to an undergarment. More particularly, it relates to a vapor-permeable article which is elastic in the longitudinal direction, which provides greater comfort for the wearer.

BACKGROUND OF THE INVENTION

Disposable absorbent articles such as diapers, adult incontinence articles, sanitary napkins, and panty liners are well known. They include a user-facing and secreted fluid-permeable topside, an absorbent structure therein for receiving fluids, and a liquid-impermeable backside.

It is known to create a backside so as to allow contact with the environment to be so-called breathable. The breathability allows a better amount of air to penetrate through the backsheet, which is proportional to the open area (the sum of all openings in the backsheet) of the backsheet. Any improvement in breathability leads to a compromise to prevent leakage, which is the primary function of the backsheet.

A number of solutions are known which combine conflicting demands on air permeability and fluid impermeability. The fact that there is a lack of commercially available and breathable disposable absorbent articles that are both flexible and flexible indicates that the results achieved do not meet the required technical characteristics and economically acceptable conditions.

Absorbent articles worn in the crotch portion of an undergarment and attached thereto by so-called adhesive fasteners are intended for daily wear requiring breathability, a feature which is intended to enhance the wearing comfort of the article. It is generally believed that the loss of water vapor from the product reduces sweating, staleness, and warmth.

It is also known that in order to be user-friendly, these products must be flexible. The more flexible they are, the less user will become aware of their use. The comfort provided creates a situation similar to that in which no absorbent article is used.

Flexibility can be easily achieved by reducing the amount of material in the product or by replacing rigid or inflexible components with more flexible components. It is known that extreme elasticity can also reduce the absorbent performance of such a product, for example by having an insufficient amount of absorbent material or by shirring the material and forming tufts, or possibly densifying the material during wear. An excessively flexible article can also cause handling problems, particularly when fastening the article to the undergarment.

The problem of excessive elasticity of the material due to the low amount of inelastic material is discussed in U.S. Pat. No. 4,217,901, which describes a situation in which the stiffness of an absorbent article has increased to sufficiently increase its performance. The references to the prior art agree with the consequences which relate to comfort and were caused by stiffness requirements. This document does not mention the breathability of the product.

For these reasons, it is desirable to produce highly flexible and breathable products. The implementation of the backsheet with apertures with respect to flexibility means the implementation of a thin absorbent article and hence the existence of too much risk of leakage of liquids through the backsheet. Therefore, a smaller option was adopted

In order to prevent leakage, especially in thin absorbent articles. Only the known breathable backsheet and double backsheet for a disposable absorbent article provide alternative solutions. However, even a multilayer backsheet is in some way counterproductive because the addition of the layers increases stiffness instead of enhancing flexibility.

Methods of forming a breathable backsheet that includes more than one layer are disclosed in US 4,341,216, EP 203,821, and monolayer backsheets such as GB-A 2,184,391, 2,184,390, 2,184,389, US 4 Nos. 591 523 and 4,839,216 or EP 156,471. From U.S. Pat. No. 4,023,571, an absorbent liner is known with a breathable two-layer barrier, an absorbent layer having two major surfaces, with elongation under stress and restoration after pressure relief. . The upper liquid-permeable layer of the insert is attached to the first major surface of the absorbent layer and is less resiliently renewable than the absorbent layer, thus remaining under tension and hence elongated. As a result, the insert takes a non-planar arcuate shape. The base layer of the article is impervious to liquids. Thus, the elasticity of the article is related to the absorbent layer, not to the entire article. The article comprises a centrally placed pressure-sensitive adhesive to attach the article to the undergarment. None of these documents addresses the problem of comfort in connection with rigid or insufficiently flexible absorbent articles. Some propose to provide sufficiently absorbent material to address the problem of leakage. However, these designs increase stiffness at the expense of breathability.

It is therefore an object of the invention to define the problem of conflict between leakage through the backsheet, flexibility and breathability. The benefits of breathability and elasticity, particularly the ability to easily bend and twist in the longitudinal direction, but better in all directions, have become a key issue, especially for a daily absorbent article, such as a panty liner, sanitary napkin or incontinent pad.

It has been found that the problem associated with the apertured and breathable backsheet can be avoided while maintaining the benefits by using a water vapor permeable film. At the same time, the comfort of the absorbent article can be drastically improved by providing high elasticity in the longitudinal direction in combination with the adhesive tabs so that the water vapor permeable article is kept flat with respect to the wearer's undergarments. The flexibility is thus limited only by the material strength requirements and the manner of handling the absorbent article.

Therefore, it is an object of the invention to provide a sanitary napkin with improved flexibility, without all the aforementioned disadvantages. In particular, it is an object to achieve a high degree of flexibility and breathability, without punching the backing layer and without creating tufts and handling problems, by selecting ranges of design parameters according to the present invention.

SUMMARY OF THE INVENTION

The present invention relates to an absorbent article which is breathable, for example, a sanitary napkin, incontinent pad or trouser, which can be attached to an undergarment. The absorbent article comprises a breathable back apertured layer, the bottom surface of which is provided with an adhesive material to adhere the article to the undergarment.

SUMMARY OF THE INVENTION The present invention provides an elastic absorbent article for use in underwear, optionally including protective side flaps, comprising a backsheet with an undergarment-facing surface and an absorbent core, wherein the undergarment-facing surface comprises an adhesive for adhering the article to the undergarment. and a theoretical adhesive surface within the endless line, which is the shortest boundary line of the adhesive surface, which does not extend beyond the periphery of the garment facing surface, and wherein the backsheet is water vapor permeable and includes a liquid vapor permeable but water vapor permeable in that the ratio of the actual adhesive surface to the surface facing the bottom

-280 287970 B6 of the garment is in the range of 0.2 to 0.8, the ratio of the theoretical adhesive surface to the garment facing surface is in the range of 0.6 to 1.0 for the product with protective side flaps, and the elasticity of the product is from 1300 up to 5000 mg x cm, measured according to ASTM D1388 method.

The elasticity preferably has a value in the range from 2000 to 3500 mg x cm, in particular from 2000 to 3000 mg x cm.

It is preferred that the ratio of the theoretical adhesive surface to the garment facing surface is in the range of from 0.85 to 1.0 for a product without protective side flaps and from 0.7 to 0.9 for a product with protective side flaps.

It is also preferred that the maximum thickness of the article along an axis perpendicular to the garment facing surface is less than 3 mm, preferably in the range of 0.5 to 1.5 mm.

In another preferred embodiment, the absorbent article is elastically extensible in at least one direction parallel to the garment facing surface, preferably in two directions not parallel to each other but parallel to the garment facing surface.

The backsheet of the absorbent article may further comprise a water vapor permeable layer and at least one additional layer.

The further layer is preferably a fibrous layer and the backsheet is oriented such that its garment facing side is formed by the fibrous layer.

Finally, the water vapor article may have a permeable layer in the form of a polymer film having apertures having a molecular size.

The absorbent article of the invention may include side protective flaps, wings which at the time of use are curved around the side edges of the garment in the crotch region to improve protection against soiling of the garment. The absorbent article also includes other typical components such as an absorbent core, a back breathable layer, and a topsheet, the core being surrounded and sealed by the layers.

The adhesive material may be placed over all or a significant portion of the garment facing surface. The adhesive material is placed so that it does not cover the entire surface area. If it covered the entire area, it would have to have a fibrous structure that was arranged in a random shape or spiral. The total area of the adhesive material on the garment facing surface defines the actual adhesive surface. The theoretical adhesive surface is then determined by the perimeter of the endless line, which is the shortest line bounding the adhesive material, which does not extend beyond the perimeter of the garment facing surface itself. In a preferred embodiment, the theoretical adhesive surface has the same dimension as the actual surface covered by the adhesive material.

In order to realize the advantages of the present invention, the absorbent article as a whole needs to provide exceptional flexibility. This is measured for the purposes of the invention in the longitudinal direction by the modified ASTM D1388 method, which will be described in detail below. The term 'flexibility' used also refers to 'drapility', due to a particular behavior. It should also be noted that stiffness is a characteristic of the opposite behavior of the material and should be within a defined range.

When it is possible to select a variety of materials suitable to achieve product flexibility, the claimed range of elasticity is in fact narrow and the components of the product components should be selected from known values that should not be so high flexibility so that the overall product design is created and influenced for example absorption capacity, agglomeration or product handling. The degree of flexibility of the product as a whole is indeed given

-3GB 287970 B6 material selection, but not just this selection. In order to achieve the claimed values of elasticity, the choice of material must be balanced with other desired product characteristics, such as absorbent capacity, tuft formation, or difficulty of handling by the wearer of the article, the absorption capacity being critical for so-called breathable products. The upper limit is set with a view to achieving highly elastic absorbent articles.

The elasticity values with the size ratio of the adhesive surface provide exceptional comfort without dirt and absorption problems caused by tufts or soiling of the absorbent material, while still allowing the user to fasten the article to the undergarment without undue effort. According to the invention, the elasticity is measured in the longitudinal direction, since it is a value that is readily measurable and important. In principle, transverse elasticity can also be used at different values. Due to the low extensibility of the article in the transverse direction, it is usually not possible to make a correct measurement of the elasticity in that transverse direction.

The thickness of the insert in the preferred embodiment is less than 3 mm, in particular from 0.5 to 1.5 mm, according to the thickness measurement methods described later.

Combining the correct adhesive attachment layer with elasticity is particularly useful in the context of extensible absorbent articles.

A second key aspect of the invention is the water vapor permeability of the backsheet of the absorbent article. The articles of the invention have a backsheet without holes. This layer is impermeable to water vapor. To achieve this, the backsheet includes a water vapor impermeable layer, thereby becoming liquid impermeable. This can also be achieved by adding one or more layers, each providing a different function. Specifically, it may include, for example, a very thin film of thermoplastic water vapor impermeable material and another discontinuous apertured film (in order not to maintain water vapor permeability) that increases the material strength and / or additional layer giving the liner a proper appearance, e.g. more fabric-like underwear.

BRIEF DESCRIPTION OF THE DRAWINGS

Giant. 1 shows a plan view of the garment facing surface of the panty liner without protective side flaps, and FIG. 2 shows the garment facing surface of the undergarment facing the garment, with protective flaps according to an alternative embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The invention will be described with reference to panty liners, but may equally be applicable to sanitary napkins or adult incontinence pads worn under an undergarment and attached thereto during wear.

The absorbent articles of the present invention typically comprise three major components. A liquid impermeable topsheet, a water vapor impermeable backsheet and an absorbent core surrounded by both layers, wherein the article is worn such that the visible surface of the topsheet faces the undergarment to which the article is fastened by fasteners, usually adhesive fasteners. , however, mechanical clamping elements may also be used.

The invention relates to the elasticity of the article and its permeability to water vapor. The degree of flexibility (flexibility) is determined by the material selection of the product components and their possible amount. Those skilled in the art will appreciate that in order to achieve the flexibility of the invention, the choice and amount of material must be balanced with the other desired characteristics

An absorbent article, for example having an absorbent capacity or velocity and dryness on the outside of the topsheet during use. The following description of typical materials of the major components of the absorbent article will allow to provide an almost infinite number of variations of the article within the limits of the flexibility of the present invention. Whether the product meets the flexibility requirements of the present invention can be ascertained by simple measurements by the methods described below.

Absorbent articles according to a preferred embodiment of the present invention are " resiliently expandable ", which means that after removal of the tensioning forces, the article tends to return to its original unstretched dimensions. It does not have to fully return to the original dimensions, if the absorbent article is elastically extensible, it may expand in one or two directions (which are not parallel to each other) in the plane of the article, i.e. parallel to the garment facing surface.

The materials of the elastically extensible article may be elastically extensible per se or may be modified to provide elastic extensibility. For the backsheet and topsheet resilient material, a fibrous material combined with resilient strands, a yarn or a mesh, as well as a pleated and braided material, a material rolled into a ring and the like can be used.

In the following non-limiting embodiments of the main elements of the absorbent article, a process applicable to flexible or non-extensible articles is described.

The absorbent core typically includes a primary fluid distribution layer (optional), a secondary fluid distribution layer (optional, but preferred to be included), a fluid storage layer, a fibrous layer ("dusty") located below the accumulation layer, and finally other optional components.

The primary fluid distribution layer is an optional core component and is the primary fluid distribution layer. It is usually placed under the topsheet and is in fluid contact with it. The topsheet transfers the obtained menstrual fluid to the primary distribution layer for ultimately transferring the fluid to the storage layer. This fluid transfer through the primary distribution layer takes place not only over the thickness, but also in the direction along the length and width of the absorbent article.

Also an optional component of the absorbent core of the present invention, but preferred, is a secondary liquid distribution layer located below and with the primary distribution layer through the fluid in contact. The task of the secondary layer is to receive menstrual fluid from the primary distribution layer and transfer it to the accumulation layer that is located below the secondary distribution layer. This will improve the capacity utilization of the storage layer.

The fluid storage layer positioned below the secondary distribution layer with which it is in contact with the fluid includes certain absorbent gelling materials and / or other absorbent materials that may be a carrier matrix of absorbent gelling materials. Absorbent gelling materials can be so-called hydrogels, superabsorbents, hydrocolloids. Absorbent gelling materials are those materials which, upon contact with aqueous fluids, particularly water-containing human fluids, absorb such fluids to form hydrogels. Such absorbent materials are capable of absorbing large amounts of human fluids and, in addition, can retain these fluids at moderate pressure. These absorbent gelling materials are in the form of discontinuous non-fibrous particles.

The fluid storage layer may comprise only absorbent gelling materials or may be homogeneously or inhomogeneously dispersed in a suitable carrier, or may comprise only absorbent gelling material. Suitable carriers include cellulosic fibers in the form of fibrous dust, film or paper as commonly used in absorbent cores.

-5GB 287970 B6

Modified pulp fibers, for example, reinforced pulp fibers, may also be used. Synthetic fibers may also be used, including fibers made of cellulose acetate, polyvinyl fluoride, polyvinylidene chloride, acrylates, polyvinyl acetate, insoluble polyvinyl, polyvinyl alcohol, polyethylene, polypropylene, polyamides, polyesters, bi-component fibers, 5 ternary fibers, mixtures thereof, and mixtures thereof. preferred, having a fineness of about 25 denier. It is also preferred that the fibrous surface is hydrophilic or can be treated as hydrophilic. The storage layer may also include filler materials, for example, Perlite, diatomite, vermiculite, etc., which reduce the rewetting problem.

After inhomogeneous dispersion in the carrier, the storage layer may be homogeneous, i.e. it may have a distribution gradient in one or more directions, within the dimensions of the storage layer. Non-homogeneous distribution may also refer to carrier laminates enclosing partially or completely absorbent gelling materials. When an absorbent gelling material is used, it is preferred that the storage layer contain about 15 to 100% absorbent gelling materials and from 0 to 85% carrier. More preferably, from 30 to 100%, preferably from 60 to 100% of absorbent gelling materials, and from 0 to 70%, most preferably from 0 to 40% of carriers.

Suitable absorbent gelling materials which can be used herein very often comprise water-insoluble, slightly cross-linked, partially neutralized polymeric gelling materials. These materials form a hydrogel upon contact with water. Such polymeric materials can be prepared from polymerizable, unsaturated, acid-containing monomers. Suitable unsaturated acidic monomers used in the preparation of the polymeric absorbent gelling materials of the present invention include those disclosed in U.S. Patent 4,654,039. Preferred monomers include acrylic acid and 2-acrylamido-2-methyl-propane. sulfonic acid. Acrylic acid is particularly preferred in the preparation of polymeric gel materials. Polymeric components formed from unsaturated, acid-containing monomers can be closely associated with other types of polymer moieties, such as starch or pulp.

Graft starch polyacrylate materials of this type are particularly preferred. Preferred polymeric absorbent gelling materials that can be prepared from conventional types of monomers including hydrolyzed acrylonitrile graft starch, graft starch, polyacrylate graft starch, polyacrylate, maleic anhydride copolymers, and combinations thereof. Most preferred are polyacrylates and poly35 acrylate graft starches.

Since these materials are present in particulate form, the use of these materials in the form of macrostructures, for example fibers, wafers or strips, is also contemplated. These macrostructures are commonly prepared by converting particulate absorbent gelling materials into aggregates, using a suitable crosslinker to thicken and form a coherent mass, and then process the compacted aggregate by reacting the crosslinking agent with the particulate absorbent gelling material to form a coherent mass. by forming a composite, porous, absorbent macrostructure as disclosed, for example, in U.S. Patent 5,102,597.

Another optional component included in the absorbent core of the present invention is a fibrous layer located just below the storage layer. This fibrous layer is commonly referred to as a " dust " layer because it provides a substrate on which absorbent gelling material settles in the storage layer during manufacture of the absorbent core. This layer may include all of the materials that have been mentioned for the storage layer. In fact, in these 50 cases where the absorbent gelling material is in the form of macrostructures, for example in the form of fibers, wafers or strips, the fibrous layer need not be included. However, since this layer provides additional fluid handling capabilities, such as a wick effect along the length of the pad, its inclusion in the absorbent core of the present invention is preferred.

-6GB 287970 B6

The absorbent core of the invention may include other non-soyne components normally found in absorbent fabrics. For example, a reinforcing scrim of thin cotton fabric may be inserted into or between the respective core layers. The mule may be configured so as not to form interlayer fluid transfer barriers, especially when placed between respective layers of the absorbent core. By providing structural integrity, which typically occurs as a result of thermal bonding, a reinforcing scrim for absorbent structures is not required as it could preclude achieving the intended flexibility.

Another component that could be incorporated into the absorbent core of the present invention (preferably into or as part of a primary or secondary distribution layer) is a odor control agent. It may be an active carbon coated with a odor-removing substance or an active carbon mixed into such a substance, a particularly suitable component being zeolite or clay materials which are incorporated into the absorbent core. These components can be used in a predetermined shape, but are often supplied as discrete, non-fibrous particles.

The top layer is supple, soft to the touch and non-irritating to the skin. As already mentioned, the topsheet may be elastically extensible in one or both directions. In addition, the topsheet is permeable and allows fluids (menstrual or urine) to easily penetrate through its thickness. A suitable topsheet can be manufactured from a wide variety of materials, for example, woven and nonwoven materials, polymeric materials, porous foams, reticulated foams, thermoplastic films or scrims. The woven and nonwoven materials can be made of natural fibers (wood or cotton fibers), synthetic fibers (polymer fibers, for example polyester, polypropylene or polyethylene fibers) or combinations of natural and synthetic fibers.

The preferred topsheet is selected from nonwoven topsheets with high fiber resiliency and topsheets made of apertured films. Perforated films are particularly preferred because they are permeable to body exudates but are not yet absorbent and have a reduced tendency to allow liquids to return and moisturize the wearer ' s skin. Thus, the surface of the formed film which is in contact with the skin remains dry and does not pollute the linen, and at the same time creates a much more pleasant sensation for the wearer. Suitable films are described in U.S. Pat. Nos. 3,929,135, 4,324,246, 4,342,314, 4,463,045, 5,006,394. Especially preferred are micro-hole films of U.S. Patent Nos. 4,609,518 and 4,629,643.

Also useful for the present invention is a topsheet not having homogeneous fluid distribution passages but only a portion thereof. Such topsheets have fluid passages oriented such that the result is a centrally permeable and peripherally impermeable topsheet.

The surface of the topsheet body formed from the film may be hydrophilic to assist faster fluid transfer through the layer, which would not happen if it were not hydrophilic. In a preferred embodiment, a surfactant according to said U.S. Pat. No. 4,950,254 is added to the polymeric film of the topsheet.

The backsheet, permeable to water, but not to liquids, prevents exudates absorbed and accumulated in the absorbent core from wetting articles which come into contact with the sanitary napkin, such as panties, pajamas and underwear. The backsheet comprises at least a layer of water vapor permeable material, it may also include a polymeric film having apertures which provides the layer with structural strength. A fibrous fabric may also be included in the backsheet to form the garment facing surface. The water vapor permeable layer may have a polymeric film having holes of molecular size. For example, the film may be a structure commonly known in the art under the designation Goretex or Sympatex. The films of EP 293482 are also considered useful.

The adhesive panty grip is positioned on the backsheet surface facing the undergarment.

-7GB 287970 Β6

According to the invention, it is important that the ratio of the theoretical adhesive surface to the actual garment facing surface is within the range of the claims of the invention. The theoretical adhesive surface is defined by the surface area within the endless line that closes the adhesive fastener of the panty that does not extend beyond the perimeter of the garment facing surface.

The ratio of the actual adhesive surface to the garment facing surface is from 0.2 to 0.8. For example, if there is a rectangular adhesive surface on the garment facing surface, then the theoretical adhesive surface and the actual adhesive surface will be identical surfaces as shown in Figure 1, in which the adhesive portion 22 is shown in oblique lines. The closure line 26 encloses a theoretical adhesive surface 24 that is identical to the surface covered with adhesive 22. In absorbent articles having protective side flaps, as shown in FIG. 2, the three adhesive surfaces are less than the theoretical adhesive surface 24 bounded by the closure line 26. if the backsheet is elastically extensible, the adhesive surfaces are measured on the unstretched layer prior to stretching.

Adhesive panty fasteners may include any adhesive material or adhesive used for this purpose in the art, but pressure sensitive materials are preferred. Suitable adhesive fasteners are described in U.S. Patent 4,917,697.

In order to maintain the permeability of the backsheet for the water vapor of the present invention, it is important that the adhesive tab does not cover the entire surface of the garment-facing backsheet. For this purpose, it is possible to use an adhesive material that seals only about 80% of the garment facing surface. For proper attachment of the article to the undergarment, it is considered necessary to include an adhesive portion that would cover at least 20% of the surface.

An alternate pattern adhesive panty is used, for example, a dotted pattern, a pattern made up of lines, a random or designed fibrous pattern (spirals) to provide water vapor permeability to the sanitary napkin.

In addition, other fasteners may be used instead of adhesive. These other types of grips are arranged in the same or similar patterns as the adhesive grips. Such anchors include, but are not limited to, conventional VELCRO hook material. The protective side flaps may also optionally include attachments which may be of the various types mentioned above for added safety. The tabs help the protective side flaps to remain in place when placed in the crotch area.

Before using the absorbent article, the panty adhesive fasteners are protected from contamination and improper attachment by a protective layer of silicone coated paper, plastic film, or other readily removable material. The protective layer may be one or more pieces that cover the individual adhesive surfaces.

The elasticity / shirring of the absorbent article is measured as follows.

ASTM D1388-64, a Standard Method for Testing Stiffness of Fabrics, modified as described below, is used.

The test is based on the principle of a cantilever beam. The distance of the sample strip that can be stretched on a flat surface before bending at an angle of 41.5 degrees is measured. For the calculation of the elasticity / shirring value, the correlation between the weight of the sample and its stiffness, measured by bending the sample under its own weight at a given angle and under specified test conditions, is used.

The elasticity test is only one way of measuring the elasticity of a sample and it is believed that the elasticity is one of the components that a user of an absorbent article refers to as softness. This measurement method should be monitored as closely as possible and should not be confused with multidirectional measurement

For this invention, only the longitudinal direction measurement method described is necessary for this invention, while the transverse direction measurement method may be used for very wide and exceptionally flexible products.

In general, one strip of sample should be tested only once. The two sides of the sample strip should be tested on different sample strips. The strips must be handled with great care to avoid wrinkles, wrinkles, bends, etc. The test is performed on products before folding or folding at the manufacturer before packing. If the manufacturer folds the sample, it must be slightly straightened before the test is carried out. If only folded specimens are available, the elasticity / shirring measurement must be adjusted by measuring the specimen between the fold lines. The test should be carried out on complete specimens, ie all layers are spread over the entire surface of the specimen and bonded together properly. For each sample, four different strips with the topsheet facing upwards and four different strips with the topsheet facing downwards should be measured. The strips are measured in the longitudinal direction.

The testing equipment consists of a stiffness tester type SDL 003B Intemational, from Carl von Gahlen, Germany, and a two-sided cutter for a width of 25.4 mm, placed in an air-conditioned room at 21.7 degrees Celsius. In addition, talc powder, a Zerostat antistatic gun to prevent static discharges on a test device and / or fabric supplied by US, Dishwasher, Inc, Columbia, MO 65201 are required. The use of this gun is a proven method for removing static charges.

Samples are prepared by placing them in a room where air recirculation and maximum moisture / temperature balance are ensured.

Eight samples were cut using a cutter, 25.4 mm wide. The strip of specimens should be cut lengthwise from the center of the absorbent article and at the same time so that it is rectangular and free of creases. Typical sample dimensions are 2.54 x 14.0 cm, may be shorter, but must include absorbent material throughout. The cover paper is then removed and the sample is weighed in mg and the weight is rounded to the nearest mg. Subsequently, the sample is carefully covered with a minimum amount of talc powder to avoid possible sticking, the rest of the talc is blown away. The sample and powder are weighed, rounded to the nearest mg. For each sample, the basis weight is calculated by measuring the sample with and without powder and the actual surface area. A sample is discarded if its weight increases by more than 2.0 mg / cm2 after the addition of the powder.

The test equipment should be placed on the bench directly in front of the operator; the bench should not be exposed to vibrations, airflow or drafts during measurement.

The operator should sit or stand in front of the machine, select a position so that when looking in the machine's mirror, the front alignment line overlaps the rear alignment line. If he sees only one line, then his position is correct.

The tester will do the following when testing.

Removes the sample slide ruler from the sample slot on the upper deck of the tester. It then places the sample strip on the sample slot so that one end of the strip coincides with the vertical edge of the test device. The strip should be placed as close as possible to the side guide of the sample slot, but should not touch it. It then places the slide ruler on top of the sample strip so that its front edge is aligned with the edge of the sample strip in the tester and touches the side guide. Carefully position the sample slide ruler so that the sample is not wrinkled or moved forward.

The next step is to pull the free end so that only a small force is applied to move the slide ruler slowly and smoothly forward, at a rate of about one centimeter per second. As the slide ruler moves forward, the sample moves at the same slow speed.

-9EN 287970 B6

When the slide ruler and the sample are ejected beyond the edge of the tester, the sample strip begins to bend or fold into the folds downwards. The device stops the slide ruler from moving when the leading end of the sample bar falls below 41.5 degrees of the reference lines. If the specimen tends to twist, a comparison point at the center of the front end is used.

If the sample is twisted by more than 45 degrees, then measurements cannot be made. Samples may only be measured if the length of the samples is at least 0.5 cm longer than the length of the overhanging end. For non-measurable samples, the overhang length may be measured only if a sufficiently long strip is obtained which is 0,5 cm longer than the overhang length. The length of the overhang at the top of the specimen shall be indicated, the length of the overhang being the distance from the initial 10 point of movement and the point where the sample bends over 41.5 degrees. Finally, the length of the overhang in cm is measured with a ruler and the result is rounded to the nearest cm.

The elasticity / shirring value can be expressed by the equation

G = W. L ² , where G is the elasticity / shirring, W is the basis weight of the sample in milligrams per square centimeter including talc powder, and L is the overhang length in centimeters. The result has a dimension of milligram by centimeter.

The thickness should always be measured at the thickest point, usually in the middle part of the absorbent article. By convention, the measurement is carried out on an absorbent article without a covering layer. The product should be air conditioned at 50% humidity and 23 degrees Celsius for two hours in a container which should be removed no more than five minutes before measurement.

The thickness is measured with a micrometer gauge ranging from 0 to 30 mm, capable of measuring with a tolerance of plus or minus 0.5 mm. The caliber must not be a spring gauge and should have a heel moving downwards under the influence of gravity. The heel of the micrometer has a diameter of 40 mm and is loaded with a force of 80 grams. The measurement is performed within 5 to 10 seconds after the heel has come into contact with the absorbent article. The measurement should take place frequently enough to allow statistical analysis to be carried out to determine the average thickness with a tolerance of plus or minus 0.1 mm. A detailed description of the thickness measurement is given in U.S. Patent No. 5,009,653.

Claims (8)

PATENT CLAIMS 1. An elastic absorbent article to be used under the undergarment, optionally comprising protective side flaps, comprising a backsheet with an undergarment-facing surface and an absorbent core, wherein the undergarment-facing surface comprises an adhesive (22) for adhering the article to the undergarment, the adhesive (22) has a true adhesive surface and a theoretical adhesive surface (24) within an endless line that is the shortest boundary line of the adhesive surface 45, which does not extend beyond the perimeter of the garment facing surface and the backsheet is water vapor permeable; wherein the ratio of the actual adhesive surface to the garment facing surface is in the range of 0.2 to 0.8, the ratio of the theoretical adhesive surface (24) to the garment facing surface is ranging from 0.6 to 1.0 for the article for 50 with protective side flaps and the product elasticity is from 1300 to 5000 mg x cm, measured according to ASTM D1388 method. Product according to claim 1, characterized in that the elasticity has a value in the range from 2000 to 3500 mg x cm. -10GB 287970 B6 Product according to claim 1, characterized in that the elasticity has a value in the range from 2000 to 3000 mg x cm. Product according to any one of the preceding claims, characterized in that the ratio of the theoretical adhesive surface (24) to the garment facing surface is in the range of 0.85 to 1.0 for the product without protective side flaps and of 0.7 up to 0.9 for a product with protective side flaps. Product according to any one of the preceding claims, characterized in that the maximum product thickness along an axis perpendicular to the garment facing surface is less than 3 mm, preferably in the range of 0.5 to 1.5 mm. Product according to any one of the preceding claims, characterized in that it is elastically extensible in at least one direction parallel to the surface facing the bottom 15, preferably in two directions not parallel to each other but parallel to said garment facing surface. An article according to any one of the preceding claims, characterized in that the backing layer comprises a water vapor permeable layer and at least one further layer. The article of claim 7, wherein the further layer is a fibrous layer and the backsheet is oriented such that its garment facing side is formed by the fibrous layer. The article of claim 7, wherein the water vapor permeable layer is a polymer film having apertures having a molecular size.