MXPA95002572A - Absorbent article that has an absorbent nucleus that accommodates the cue - Google Patents

Abstract

An absorbent article is provided for absorbing body fluids having an absorbent core positioned between a fluid permeable cover and a fluid impervious separator. The absorbent core includes a central longitudinal bending axis which extends virtually to the length of the absorbent core. The central longitudinal axis generally divides the absorbent core into the first and second longitudinal members having an outer boundary and wherein the first member has a second axis of flexion and the second member has a third axis of flexion. Flanking the outer boundary of the first and second members are a third and a fourth longitudinal absorbent members, respectively. The third and fourth absorbent members are positioned such that, when the absorbent article is subjected to lateral compressive forces, the first and second members preferably bend convexly upward, and said absorbent core generally acquires a "shaped" configuration.

Description

gl ACQKQPA M. gWRPQ Inventors: Frederich Orna Lassen, Jane Marilyn Antón and Linda Jean Chmielewski-Larsen, all of North American nationality, with addresses at 3325 Elk Creek Drive, Christiansburg, Virginia 24073; 2960 East Ridge Place, Neenah, Wisconsin 54956; and 5 Gulf Pointe Court, Bloomington, Illinois 61704; United States of America.

Owner: KIMBERLY-CLARK CORPORATION, North American, residing at 401 North Lake Street, Neenah, Wisconsin 54957-0349; United States of America.

Extract of the Invention An absorbent article is provided for absorbing body fluids having an absorbent core positioned between a fluid permeable cover and a fluid impervious separator. The absorbent core includes a central longitudinal bending axis which extends virtually to the length of the absorbent core. The central longitudinal axis generally divides the absorbent core into the first and second longitudinal members having an outer boundary and wherein the first member has a second axis of bending and the second member has a third axis of bending. Flanking the outer limit of the first and second members are a third and fourth longitudinal absorbent members, respectively. The third and fourth absorbent members are positioned such that, when the absorbent article is subjected to lateral compressive forces, the first and second members preferentially bend convexly upwards, and said absorbent core generally acquires a "W" shaped configuration.

Field of the Invention The present invention relates to disposable absorbent articles, and more particularly, to absorbent articles having a central longitudinal bending axis that allows the absorbent article to fold preferentially in a convex upward configuration when subjected to lateral compressive forces.

Background of the Invention All the forms and varieties of absorbent articles configured for the absorption of body fluids, such as menstrual fluids, urine and feces are well known. In the area of external female protection, for a sanitary napkin to receive menstrual fluids, the sanitary napkin generally forms both a longitudinal and an arched configuration due to the outline of the wearer's body within the area of the vulva, perineum and buttocks . Therefore, it has been relatively difficult to obtain a finishing adjustment of such a sanitary napkin which provides comfort to the wearer and avoids runoff at the edges thereof. Typically, in order for the sanitary napkin to have an adequate fluid capacity and a sufficient area to lie completely below the vulva, the sanitary napkin must have a width of such an extension so that it is quickly laterally compressed between the legs of the wearer . As a result of this, the sanitary napkin rapidly deforms to a shapeless condition which causes its failure. Some efforts have been made to improve the construction of the sanitary napkin, but it is still found that they are inadequate to intercept body fluids.

Summary of the Invention Briefly, this invention relates to disposable absorbent articles having a liquid permeable cover, a liquid impervious separator and an absorbent core to absorb fluid exudates from the body. The absorbent core includes a central longitudinal bending axis which extends virtually to the length of the absorbent core. The central bending axis at least partially divides the absorbent core into the first and second members. The first member includes a second axis of longitudinal bending, and a second member includes a third axis of longitudinal bending. The central longitudinal bending axis allows the absorbent core to be bent preferentially upward towards the cover and along the center flexion axis in a convex configuration when the absorbent core is subjected to lateral compressive forces. This allows the absorbent core to form virtually an inverted "V" shape.

In a preferred embodiment, the absorbent core includes the third and fourth longitudinal absorbent members that flank the first and second members respectively. This allows the absorbent article to acquire a more defined "W" shape configuration when lateral compressive forces are applied to the absorbent article.

It is a general object of the invention to provide an absorbent article which is inherently self-adjusting and shape-fitting to the body and which allows compression of the pad without destroying the basic shape thereof. A more specific object of the invention is to provide an absorbent core that will fold preferentially upward, in a convex configuration, when subjected to lateral compressive forces substantially forming an inverted "Vw" shape in the core region of the core.

A further object of the invention is to provide a sanitary napkin having a body surface that is generally "W" shaped in the central region when used.

Another object of this invention is to provide a sanitary napkin which will adapt its shape so as to conform to the changing shape of a woman's vulva region whether the wearer is motionless or in motion.

Yet another object of this invention is to provide a sanitary napkin having multiple longitudinal absorbent members that are preferentially bent upward toward the cover in a convex configuration when subjected to lateral compressive forces.

Other objects and advantages of the present invention will be more apparent to those skilled in the art with regard to the following description and the accompanying drawings.

Brief Description of the Drawings It is believed that the invention will be better understood from the following description taken in conjunction with the accompanying drawings, wherein like reference numbers indicate the same parts through the various views, and the like parts are designated with a premium symbol.

Figure 1 is a perspective view in partial section of an absorbent article illustrating an embodiment of the absorbent core of the present invention with the central longitudinal axis of flexion virtually dividing the absorbent core into the first and second members.

Figure 2 is a perspective view of another embodiment of an absorbent article with the cover removed and showing an absorbent core having the third and fourth members flanking the sides of the first and second members.

Figure 3 is a cross-sectional view taken along line 3-3 of Figure 2.

Figure 4 is a view of Figure 3 illustrating an "M" configuration that the absorbent core can adopt when lateral compressive forces are exerted on the absorbent core.

Figure 5 is a perspective view of an absorbent article generally showing a body-accommodating configuration, referred to herein as a "" shape, which the absorbent core can obtain when lateral compressive forces are exerted on the absorbent core.

Figure 6 is a perspective view of an absorbent article showing another configuration of accommodation to the body, referred to herein as the "pant liner" shape, which the absorbent core can obtain when lateral compressional forces are exerted on the absorbent core.

Figure 7 is a perspective view of an absorbent article showing another body-accommodating configuration, referred to herein as the "used pad" shape, which the absorbent core can obtain when lateral compressive forces are exerted on the absorbent core.

Figure 8 is a perspective view of an absorbent article showing another body-accommodating configuration, referred to herein as the "A" shape, which the absorbent core can obtain when lateral compressive forces are exerted on the absorbent core.

Figure 9 is a perspective view of another embodiment of an absorbent article having the cover removed showing an absorbent core all of fluff. The core includes the central longitudinal bending axis constructed of absorbent fluff having a lower density relative to the density of the flanking absorbent.

Figure 10 is a partial cutaway perspective view of another embodiment of an absorbent article with the cover removed showing the absorbent core having a primary absorbent, similar to that illustrated in Figure 2 and a secondary absorbent layer placed between the absorbent primary and the separator.

Figure 11 is a top plan view of the garment side of the absorbent article showing an adhesive pattern for attaching the absorbent article to an undergarment.

Detailed Description of the Preferred Modalities Referring to Figure 1, an absorbent article 10 is shown to absorb fluids from the human body. For convenience of description only, the absorbent article 10 is illustrated as a sanitary napkin for female hygiene generally having a race track shape. However, this may be a panty shield, an incontinence device, or any other disposable absorbent article that is well known in the art, and may include other shapes, such as oval, hourglass, straight-sided, closed and peripheral enclosed constructions. It should be noted that panty liners, feminine pads, and incontinence garments come in various sizes and shapes and vary in thickness.

The sanitary napkin 10 includes a liquid permeable cover 12, a liquid impervious separator 14, an outer periphery 16, and an absorbent core 18 located between the cover 12 and the spacer 14. The absorbent core 18 is positioned inwardly of the periphery 16 of the sanitary napkin 10 and includes a body facing surface 20 positioned on one side of the cover 12 and a garment facing surface 22 positioned on the side of the separator 14. Optionally, the sanitary napkin 10 may include a transfer layer 23 placed between the cover 12 and the absorbent core 18 for rapidly transporting body fluids into the absorbent core 18 and to reduce occurrences of rewet.

Describing the individual elements in greater detail, the cover 12 is oriented towards the user's body and makes contact with it and receives discharges from the body. The cover 12 is permeable to the liquid and must be flexible and non-irritating to the skin. As used herein, the term "flexible" refers to materials which are docile and quickly conform to the shape of the body or respond by easily deforming in the presence of external forces.

The cover 12 can surround the absorbent core 18 so that it completely encloses the sanitary towel 10. Alternatively, the cover 12 and the core 14 can extend beyond the absorbent core 18 and be joined peripherally together using known techniques either completely, in a manner that the entire outer periphery 16 of the sanitary napkin 10 is circumscribed by its union, or the shroud 12 and the spacer 14 may be partially peripherally joined. Typically, the cover 12 and the spacer 14 can be joined by an adhesive construction, by ultrasonic bonding, or by any joining method known in the art.

The liquid-permeable cover 12 must be sanitary, clean in appearance and somewhat opaque to hide body discharges collected and absorbed by the absorbent core 18. The cover 12 must also exhibit good continuous blow and rewet characteristics allowing the body discharges penetrating rapidly through the cover 12 to the absorbent core 18 but must not allow the body fluid to flow back through the cover 12 to the wearer's skin. Any material that meets the above criteria is suitable for use as a cover. For example, materials suitable for cover 12 may be nonwovens, perforated thermoplastic films, or combinations thereof. A nonwoven fabric made of polyester, polyethylene, polypropylene, bicomponent, nylon, rayon, or similar fibers can be used. The cover 12 may contain a plurality of perforations formed therethrough to allow the body fluids deposited thereon to pass therethrough and to the absorbent core 18.

If desired, the cover 12 can be sprayed with a surfactant to improve the penetration of the liquid into the absorbent core 18. The surfactant is typically non-ionic and must be non-irritating to the skin.

The transfer layer 23 is preferably composed of a fibrous blend of polyester, rayon and a polymeric fiber such as that marketed by C. Itoh & Co, under the trademark "CHISSO". A highly preferred composition is composed of 50% polyester fibers with a length of about 3 to about 6 mm, about 30% straight rayon fibers with a fiber length of about 5 to about 10 mm, and the rest of CHISSO with the fiber length also from around 5 to around 10 mm. Other compositions will occur to those of ordinary skill in the art and can be substituted with due consideration for the functional requirements of the transfer layer, for example, a rapid transmission of the fluid down to the Z-direction. It is important for the functionality of the absorbent core 18 that it has the mobility to assume various configurations that accommodate the body. Therefore, the transfer layer 23 or any other material, if employed, which will reside between the cover 12 and the absorbent core 18, is secured in such a way that it will not impede this functionality. Therefore, the transfer layer 23 must allow the absorbent core 18 to bend convexly, to form an inverted "V" when the lateral compressive forces are exerted on it.

The liquid impervious separator 14 can be of any desired material that is flexible and prevents the fluid of the intercepted body from soiling the wearer's clothing. Any material used in the prior art for such purposes can be used here. Suitable materials include the recorded and non-engraved thermoplastic films and a laminated tissue. The preferred material is a polyethylene film.

The absorbent core 18 is interposed between the cover 12 and the separator 14. This construction prevents the absorbent material from breaking or peeling away while the absorbent pad 10 is used and also ensures adequate containment of the body discharges. This arrangement also helps to provide a unitary assembly of the sanitary napkin 10. Any attached arrangement providing capture of the absorbent core 18 between the cover 12 and the spacer 14 and a unitary assembly is suitable. The absorbent core 18 serves to collect and retain discharges from the body, particularly the menstrual and blood fluids deposited thereon or which otherwise pass through the liquid-permeable cover 12.

The absorbent core 18 may be any absorbent material which is generally conformable and non-irritating to the skin of the wearer and is capable of absorbing and containing liquids and certain exudates from the body. The absorbent body 18 can be used in a wide variety of sizes and shapes of absorbent articles, such as rectangular, hourglass or racetrack to name only a few.

The absorbent core 18 can be constructed of crushed wood pulp, creped cellulose wadding, absorbent foams, absorbent sponges, superabsorbent polymers, absorbent hydrogel materials, polymeric fibers, or any equivalent materials or combinations of materials. Preferably, the absorbent core 18 is a tissue formed by melt blowing of one or more layers. Each layer can have a basis weight of about 30 grams to about 100 grams per square meter (gsm) and be made according to the United States patent No. 4,798,603 issued to Meyer and assigned to Kimberly-Clark Corporation, whose full description is incorporated herein by reference and becomes a part of it. The total absorbent capacity of the absorbent core 18 must, however, be compatible with the exudate load design for the intended use of the sanitary napkin 10. In addition, the size may be varied to accommodate a predetermined expected amount of exudate fluid volume. For example, a different absorbent capacity can be used for sanitary napkins intended for overnight use or for sanitary napkins that are intended for use by quinceañeras, as compared to those intended for use by a mature woman.

Generally, the sanitary napkin 10 and the absorbent core 18 have a common longitudinal center line Y-Y. The absorbent core 18, as illustrated in Figure 1, is constructed of a meltblown tissue that approximately has two-thirds of the bi-folded tissue to form the left and right halves of the absorbent core 18. Placed along of the Y-Y longitudinal center line, and extending virtually along the length of the absorbent core 18, is a central longitudinal bending axis 24. The central flexion longitudinal bending axis 24 can be positioned transversely, for example, along the X-X axis and outside the center of the Y-Y longitudinal centerline, for a distance ranging from about 0 to about 10 mm, without adversely affecting the functionality of the absorbent core 18 to adopt various configurations that accommodate the body . Preferably, the central longitudinal bending axis 24 is aligned along the longitudinal center line Y-Y thereby dividing the absorbent core 18 into two substantially symmetrical opposed halves. The central longitudinal bending axis 24 may extend longitudinally from about 50 to about 100% of the length of the absorbent core 18, and advantageously, it will extend for about 75 to 100% of the length of the absorbent core 18.

As shown in Figure 1, the central bending axis 24 divides the absorbent core 18 into a first member 26 and a second member 28 which correspond to the right and left halves of the absorbent core 18. The central longitudinal bending axis 24 provides a means for directing fluid flow down the Z-direction and into the absorbent core 18. The central longitudinal bending axis also directs the body fluids longitudinally, along the length of the absorbent core 18, reducing the possibility for the body fluid to traverse transversely, for example, along the X-X direction, of the sanitary napkin 10. Therefore, there is a minor possibility that the body fluids cause a lateral failure and there is a greater use of absorbent capacity.

The central longitudinal axis 24 may have a cut or channel 30 having a "V" or "U" shape. The channel or cut 30 extends through about 3 to about 99% of the absorbent core 18, more preferably through about 40 to about 95% of the absorbent core 18, and more preferably through at least about 80% of the absorbent core 18. Advantageously, the cut or channel 30 forms a bag or well in the Z-direction to receive body fluids. This configuration allows rapid absorption of the body fluid without the usual damage encountered when the fluid receiving surface located adjacent the user's skin is flat or cup-shaped (concave).

The channel 30 should not extend completely through the absorbent core 18. It has been discovered that such a configuration allows the absorbent core 18 to unpredictably and undesirably form a "V" shape, unless other means are amplified to ensure that the absorbent will form an inverted "V" shape.

It is important for the functionality of this invention that the absorbent core 18 be fastened to the separator 14 by means which allow the absorbent core 18 to be bent upward along the central, longitudinal axis of flexure 24 when lateral compressive forces are applied to the absorbent core 18. Such fastening means include the use of ultrasonics to intermittently knit the absorbent core 18 to the separator 14 and / or the cover 12, or to apply a thin layer or intermittent layer or pattern of adhesive construction. Suitable adhesives may be of the type well known in the art of disposable absorbent articles. Other means for securing the absorbent core 18 are equally acceptable as long as the securing does not interfere with the ability of a central longitudinal bending axis 24 to preferably be bent upwards to form a convex configuration.

The central longitudinal bending axis 24 at least partially divides the absorbent core 18 into a first member 26 and a second member 28. Since members 26 and 28 are similar in construction, only one will be described. The first member 26 has a longitudinal outer boundary 32 and the spaced-apart transverse ends 34, only one of which is shown. The outer boundary 32 and the transverse end 34 partially define the outer perimeter of the absorbent core 18. The first member 26 includes a second bending axis Y'-Y 'located laterally to one side of the central longitudinal bending axis 24. During use , the second bending axis Y'-Y 'allows the lateral torsional forces to be distributed longitudinally through the central longitudinal bending axis 24. Without the second bending axis Y' -Y ', these forces could otherwise twist the central longitudinal bending axis 24 to an undesired configuration. The central longitudinal bending axis 24, in combination with the second and third bending axes Y'-Y 'and Y' '-Y ", respectively, allow the absorbent core 18 to fold preferentially up along the axis of flexure 24 and towards the cover 12 in a convex configuration when the sanitary napkin 10 is subjected to lateral compressive forces The first member 26 and the second member 28 of the absorbent core 18 are allowed to separate from one another causing the absorbent core 18 to acquire Virtually an inverted "V" shape.Also, by longitudinally distributing the torsional forces, the absorbent core 18 will generally accommodate various body geometries and adapt to the wearer.It should also be recognized that, if the absorbent core 18 is sufficiently encompassed , that the second and third bending axes Y'- 'and Y' '-' 'may allow the absorbent core 18 to bend along these axis s to acquire a "W" shape. Preferably, the second bending axis Y'-Y 'is separated by a distance between about 5 mm to about 25 mm from the central longitudinal bending axis 24. The second bending axis Y'-Y' may be one or more cuts 36, the recesses (such as the openings substantially along the Y'-Y 'axis), internal shaped components, between faces, separations, and the like. It is important for this invention that the second bending axis Y'-Y 'allows fluid communication on either side of the shaft. By "fluid communication" we mean that the second axis of deflection Y'- 'does not significantly impede transversal transference-migration (in the X-X direction of the body fluid through the absorbent core 18. This also allows a greater utilization of the absorbent capacity of the sanitary napkin 10.

The cuts 36 extend through at least about 75% of the thickness of the first member 26. Advantageously, the cuts 36 extend through about 90% thickness and optimally 100%. As used herein, the term "thickness" means the distance occupied by the absorbent material as measured in the Z-direction. The cuts 36 do not extend through the separator 14. Each cut 36 is spaced apart longitudinally by an adjacent cut 36 by a distance of about 5 mm to about 35 mm and, preferably, from about 10 mm to about of 30 mm. During use, the cuts 36 operate cooperatively to advantageously produce stress relieving areas on the first member 26.

Referring to Figure 2, another embodiment of the sanitary napkin 10 'is shown but without a cover. In this embodiment, the absorbent core 18 includes the addition of a third and a fourth longitudinal absorbent member 38 and 40 located on one side of the first and second members 26 and 28, respectively. The first and second members 26 and 28 are similar to those described above. For the purposes of describing the invention, only the third longitudinal absorbent member 38 will be described further. The third longitudinal absorbent member 38 has a predetermined thickness which may be less than, equal to or greater than the thickness of the first member 26. The thickness of the third longitudinal absorbent member 38 may vary from about 2 mm to about 20 mm. mm. The third longitudinal absorbent member 38 has an internal longitudinal surface 42 and an outer longitudinal surface 44. The inner surface 42 is positioned laterally to, but spaced from, the outer boundary 32 of the first member 26. The inner surface 42 of the third member 38 can be spaced apart from the outer boundary 32 of the first member 26 by a distance ranging from about 3 mm to about 25 mm. Preferably, the inner surface 42 is spaced from the outer boundary 32 by a distance which is virtually equal to the predetermined thickness of the third longitudinal absorbent member 38. This allows the inner surface 42 of the absorbent member 38 to properly contact the boundary. outer 32 of first member 26, allowing sanitary pad 10 'to adopt various configurations in response to lateral compressive forces typically encountered in sanitary pad 10' during use.

The outer surface 44 is positioned on one side of the outer periphery 16 of the sanitary napkin 10 '. The longitudinal outer surface 44 may be positioned inwardly of the outer periphery of the sanitary napkin 16 by a distance of about 1mm to about 25mm and, more preferably, from about 5mm to about 20mm. This distance reduces or prevents the possibility that the body fluid not absorbed within the absorbent core 18 migrates to the outer periphery 16 of the sanitary napkin 10 'and possibly contributes to a failure of the sanitary napkin 10' to capture and retain the fluid of the body.

Referring to Figures 3 to 8, during use, when the sanitary napkin 10 'is subjected to lateral compressive forces, the sanitary napkin 10' and the central longitudinal flexion axis 24 can assume a number of different configurations varying from a configuration at rest, shown in figure 3, to a configuration in use "W" shown by figure 4. Generally, figures 5 to 8 show the most common forms assumed by the sanitary napkin 10 according to the anatomy of the wearer. The sanitary towel 10 'can be divided into three virtually identical regions: 1) an anterior region 60; 2) a posterior region 62; Y 3) a central region 64 placed between them.

In Figures 5 to 8, the anterior region 60 is that area of the sanitary napkin 10 'that would be facing forward when placed in an undergarment of the wearer. In these figures, the anterior region 60 is generally located outside the object area to direct the compressional forces, such as those exerted on the sanitary napkin 10 'by the thighs of the wearer during use, so that it retains a virtually circular shape . During use, the anterior region 60 may also acquire an open cup shape, towards the body, slightly upwards. However, the shape of the posterior region 62 and the central region 64 of the sanitary napkin 10 'are preferably affected by the anatomical geometries of a woman. Figures 2 and 5 to 8 illustrate the ability of the absorbent core 18 of this invention to conform to a variety of body shapes during rest and during activities.

Referring to Figures 2, 4, and 5, the absorbent core 18 allows the sanitary napkin 10 'to assume the configuration generally known to those skilled in the art as a "W" configuration in this configuration, the posterior region 62 of the The sanitary napkin is adapted to the wearer's gluteal canal by bending, as seen from the central region 64 to the posterior region 62, along the longitudinal bending axis 24 upward toward the wearer's body. The upward curvature of the absorbent core 18 forms an inverted "V" configuration having a vertex 66. The apex 66 of the convexly shaped body surface remains the apex 66 within the posterior region 62. Since the sanitary pad 10 'in all probability will be used in a wearer's undergarment, the forces acting upward of the undergarment will preferably cause the back region 62 and the back part of the center region 64 to curl upward toward the wearer's body and follow the curve of the buttocks. The apex 66 of the posterior region is adapted to fit in the gluteal groove of the user when it is used. The apex 66 is generally located symmetrically between the outer periphery 16 of the sanitary napkin 10 'and along the longitudinal centerline Y-Y. The apex 66 fits in the gluteal groove of the buttocks to provide stability against the sideways movement of the sanitary napkin 10 '.

The central region 64 adopts a shape that is better illustrated in Figure 4. When the sanitary napkin 10 'is subjected to lateral compressive forces, such as those when the sanitary napkin is being used, the cover 12 and the absorbent core 18 are generally folded in cooperation along the longitudinal bending axis 24 to a convex upward configuration. The internal longitudinal surface 42 of the third and fourth longitudinal absorbent members 38 and 40 remains on one side of the outer boundary 32 of the first and second members 26 and 28, respectively, thereby transferring the lateral compressive forces along the length of the second and third bending axis Y'-Y 'and Y "-" to the central longitudinal bending axis 24. The outer longitudinal surface 44 of the third and fourth absorbent members 38 and 40 advantageously moves upwards to form a barrier which helps to prevent the fluid and body from escaping from the sanitary pad 10 'through the outer periphery 16. Thus, the sanitary pad 10' generally assumes a "W" shaped cross section in the central region 64.

Referring to Figures 2 and 6, the absorbent core 18 allows the sanitary napkin 10 'to assume another configuration described herein as a "pant liner" configuration. In this configuration, the posterior region 62 of the sanitary napkin 10 is similar to that described above for the posterior region 62 of the "W" shape. However, the central region 64 adapts a configuration wherein the first and second absorbent members 26 and 28 remain in face-to-face contact with each other and do not bend upwardly along the longitudinal axis Y-Y. The internal longitudinal surface 42 of each of the third and fourth absorbent members 38 and 40 moves inward toward the longitudinal exterior boundary 32 of each first and second member 26 and 28 to form a well 68 through the central region 64.

Referring to Figures 2 and 7, the absorbent core 18 allows the sanitary napkin 10 'to assume another configuration described therein as a "used pad" shape, the shape of the anterior region 60 and the posterior region 62 is similar to that described above for the "W" form. However, the central region 64 adapts a different form. In this configuration, the lateral compressive forces cause the first and second members 26 and 28 to bend upward along the central longitudinal bending axis 24 toward the wearer's body to form a convex configuration having a vertex 66. The members third and fourth absorbers 38 and 40, however, remain substantially flat.

Referring to Figures 2 and 8, the absorbent core 18 allows the sanitary napkin 10 'to assume another configuration described therein as an "A" shape. The central region 64 and the posterior region 62 of the sanitary napkin are adapted to the gluteal groove of the wearer by bending, as viewed from the central region 64 to the posterior region 62, along the central longitudinal bending axis 24, upwards towards the surface facing the body, forming an inverted "V" configuration and having a vertex 66. The apex 66 of the convexly shaped surface facing the body remains the apex 66 within the posterior region 62. The vertex 66 of the posterior region is adapted to fit in the gluteal groove of the wearer when used. The apex 66 is generally located symmetrically between the outer periphery 16 of the sanitary pad 10 'and along the longitudinal center line Y-Y.

The facing surface 22 of the first and second members 26 and 28 of the absorbent core 18 is secured to the separator 14 by an adhesive construction (not shown) generally well known to those of ordinary skill in the tie. In securing the absorbent core 18 to the spacer, it is important that the region of the central longitudinal bending axis 24 remain flexible as compared to the flanking regions. Thus, less than about 80% of the facing surface of the garment 22 is secured to the separator 14, and preferably, less than about 50% is secured to the separator 14. Other methods for securing the absorbent core 18 to the separator 14 (for example, ultrasonic, heat etching, and the like) are equally acceptable as long as the region of the central longitudinal bending axis 24 remains flexible as compared to the flanking regions.

Referring to Figure 9, another embodiment of the sanitary napkin 10"without a cover is illustrated In this embodiment, the absorbent core 18 is constructed of an absorbent fluff well known in the art of absorbents. at least partially divides the absorbent core 18 into a first member 26 and a second member 28 which is similar to that described above for Figure 1. The central longitudinal bending axis 24 is shown as an area or region of low absorbent. density 48. The density of the absorbent 48 should be from about 75% relative to the density of the surrounding absorbent and, preferably, it is from about 30 to 50%. The low density absorbent 48 can include a channel or cut (not shown) similar to that discussed above for Figure 1. The low density absorbent 48 can have a height virtually equal to the height of both the first member 26 and the second member 28, but that is not required. The low density absorbent 48 is in face-to-face contact with the first and second members 26 and 28 so that the fluids making contact with the low density absorbent 48 will be pulled out of the side-to-body surface. of the absorbent core 18 already inside the higher density absorbent of the first and second members 26 and 28. A higher density absorbent material can also be placed at the bottom of the central, longitudinal axis of flexure 24 in order to provide a reservoir for retaining the body fluid absorbed. The high density absorbent material, which may contain superabsorbents or the like, may be wood pulp board, a mixture of densified pulp polyethylene, absorbent tissue impregnated with superabsorbent, cardboard or pulp board that has been crushed to make it more flexible The low density absorbent 48 can be loose cell associated loose cellulose fibers, for example, wood pulp fluff, regenerated cellulose, or cotton fibers. The low density absorbent 48 may also be bicomponent meltable fibers having an outer absorbent core, which melts at relatively lower temperatures, and an internal absorbent core which melts at higher temperatures. Wood pulp is often the material of choice primarily because it is cheap and readily available.

Referring to Figure 10, another embodiment of the sanitary napkin 100 is illustrated, again without a cover. The sanitary pad 100 includes a liquid impervious separator 114, a periphery 116 and an absorbent core 118 located between the cover and the spacer 114. The absorbent core 118 is positioned inwardly of the outer periphery 116 of the sanitary napkin and includes a surface facing the body 120, positioned on one side of the cover and a face facing surface garment 122 positioned on the side of the separator 114. Optionally, the sanitary napkin 100 may include a transfer layer (not shown) placed between a cover and the absorbent core 118 for rapidly transporting the body fluids into the absorbent core 118 and for reducing the occurrence of re-wetting.

The absorbent core 118 includes a primary absorbent 124 which is similar in function, construction and materials used in the absorbent core 18 described above for Figures 1 and 2 and includes an additional secondary absorbent layer 126 underlying the primary absorbent core 124. secondary absorbent layer 126 is positioned between primary absorbent 124 and liquid-impervious separator 114. Secondary absorbent layer 126 has an absorbent capacity which is adapted to assist primary absorbent 124 in retaining the body's fluid that sticks to the body. sanitary towel 100. Suitable absorbers that can be used to construct the secondary absorbent layer 126, in addition to the absorbent materials described above, include a coform absorbent having a basis weight ranging from about 90 grams per square meter to about 250 grams per square meter. The coform is a combination formed by air of polymers formed by meltblowing such as polypropylene, and absorbent fibers, such as cellulose. The secondary absorbent layer 126 is shown as having a free, commerical edge with the outer periphery 116 of the sanitary napkin 100, but it may be located inward of the outer periphery 116 to prevent migration of the body fluid to the outer periphery 116 which could cause the sanitary towel to run off. During use, the primary absorbent 124, the secondary absorbent 126, the separator 114 and the cover operate cooperatively to acquire any of one or more of the aforementioned configurations but, preferably, will be adapted to form a "W" shaped configuration. in the area where the lateral compressive forces are exerted on the absorbent core 118.

Referring to Figure 11, the garment side of the separator 114 may further comprise means for securing the sanitary towel 10 to an undergarment. Pressure sensitive adhesive 200 has been commonly found to work well for this purpose. An adhesive pattern virtually in the form of a diamond pattern is preferred, because it allows the absorbent core 18 to conform to the lateral compression forces exerted on the sanitary napkin 10. Securing the undergarment of the wearer may also be effected. by using a material having a sufficiently high coefficient of friction placed on the garment side of the separator 14 (not shown) or a combination of adhesive and frictional means. Typically, the adhesive 200 is covered with a removable strip of peel (not shown) to protect the adhesive prior to the use of the sanitary napkin 10. Materials that can be used as a peel strip are also known to those with ordinary skill in the art of disposable absorbent articles.

The sanitary towel 10 or 10 'typically has a length ranging from about 18 centimeters (cm) to about 27 cm and has a width varying from about 2 cm to about 10 cm. The sanitary napkin 10 or 10 'has a caliper greater than about 4 mm and preferably more than about 6 mm. The caliber is measured according to the following procedure.

A comparator meter, and specifically the Ames, Model 130 with a dial indicator Model 482, or equivalent, available from the B. C. Ames Company of Waltham, Massachusetts is required. The comparator meter must have a circular comparator foot made of aluminum and having a weight of 10.0 grams and a contact surface of 5.16 square centimeters. The comparator meter is set to zero. A stainless steel weight of 80.0 grams was placed on the axis that extends above the comparator dial. The comparator foot is lifted and the towel, with any loose paper of panty adhesive having been removed, is placed with the surface to the garment down on the base plate. The towel is placed on the base plate so that, when the foot is lowered, it is in the center of the towel. Try to smooth any wrinkles or avoid them on the towel. Gently lower your foot on the towel. Determine the towel gauge by reading the comparator marker 30 seconds after the foot comes in contact with the towel. Repeat the measurement 3.0 centimeters from each end of the absorbent material along the longitudinal centerline 58 of the towel. The average of three readings is the size of the sanitary napkin.

Therefore, an absorbent article has been described which conforms to the contour of the wearer in the vulva, perineum and buttock areas and which provides an increased amount of absorbent surface area, which is recessed from the skin of the wearer. the user for rapid transport of body fluids into the absorbent core.

Although the invention has been described in conjunction with several specific embodiments, it will be understood that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description.

Therefore, this invention is intended to cover all those alternatives, modifications and variations that fall within the spirit and scope of the attached clauses.

Claims (24)

Claims Having described the invention, it is considered as a novelty, and therefore the content of the following clauses is claimed as property:

1. An absorbent article comprising: a) a cover permeable to liquid; b) a separator impermeable to liquid; Y c) an absorbent core having a predetermined length placed between said cover and said spacer wherein said absorbent core includes a central longitudinal bending axis which virtually extends the length thereof, said axis at least partially partitioning said absorbent core in the first and second members, said first member has a second axis of flexure, and said second member has a third axis of flexion, whereby the axes of flexion allow the absorbent core to bend preferentially upwards, in a convex configuration towards said cover, when the absorbent core is subjected to lateral compressive forces, forming substantially an inverted "V" configuration.

2. The absorbent core as claimed in clause 1, characterized in that the bending axes allow said absorbent core to bend preferentially upwards, in a convex configuration towards said cover, when said absorbent core is subjected to lateral compressive forces, forming substantially a "W" configuration.

3. The absorbent article as claimed in clause 1, characterized in that said central longitudinal bending axis includes a channel extending through about 3 to about 99% of said absorbent core.

4. The absorbent article as claimed in clause 3, characterized in that said channel extends through about 80% of said absorbent core.

5. The absorbent article as claimed in clause 3, characterized in that said second and third bending axes are positioned laterally on one side of the central longitudinal bending axis.

6. The absorbent article as claimed in clause 5, characterized in that the second and third bending axes are laterally spaced from the central bending axis by a distance of about 5 mm to about 25 mm.

7. The absorbent article as claimed in clause 5, characterized in that the second and third bending axes each include a longitudinal cut extending through about 75% of said respective member, and wherein the bending axes second and third allow a fluid communication on each side of said axis.

8. The absorbent article as claimed in clause 6, characterized in that said second and third bending axes each include a plurality of longitudinal cuts, wherein said cuts are spaced apart and spaced by a distance of about 5 mm to about 35 mm.

9. The absorbent article as claimed in clause 1, characterized in that it comprises a transfer layer placed between the cover and the absorbent core.

10. The absorbent article as claimed in clause 1, characterized in that said central bending axis comprises a less dense absorbent region which imparts to said absorbent core a preference for acquiring an upwardly convex configuration when the lateral compressive forces are exerted on the absorbent core. absorbent core.

11. An absorbent article comprising: a) a liquid permeable cover; b) a separator impermeable to liquid; Y c) an absorbent core having a predetermined length placed between said cover and said spacer wherein said absorbent core includes a central longitudinal bending axis which extends virtually the length thereof and at least partially divides said absorbent core into the first and second members each of said members has an outer limit, said first member has a second axis of flexure, and said second member has a third axis of flexure, said absorbent core includes a third and a fourth longitudinal absorbent member positioned laterally on one side of, but spaced from said outer limit of said members first and second so that, when said absorbent core is subjected to lateral compressive forces, said first and second members preferentially bend convexly upwards and said absorbent core generally acquires a "W" shaped configuration.

12. The absorbent article as claimed in clause 11, characterized in that said third and fourth members each have an internal surface that is spaced from said respective outer limit of said first and second members by a distance of about 3mm to about 25 mm.

13. The absorbent article as claimed in clause 12, characterized in that said third and fourth members have a predetermined thickness and are spaced from said outer limit of said first and second members by a distance of at least equal to said thickness.

14. The absorbent article as claimed in clause 11, characterized in that it also includes a second absorbent layer placed between said absorbent core and said separator.

15. The absorbent article as claimed in clause 11, characterized in that said central longitudinal bending axis includes a channel or cut extending through about 3 to about 99% of said absorbent core, whereby said channel or cut-off allows the absorbent core to be bent preferentially upward in a convex configuration when said absorbent core is subjected to lateral compressive forces.

16. The absorbent article as claimed in clause 14, characterized in that said channel or cut extends through about 80% of the absorbent core.

17. The absorbent article as claimed in clause 11, characterized in that said second and third bending axes include a longitudinal cut extending through about 75% of said respective member, and wherein said cut is laterally separated from the central longitudinal bending axis by a distance of about 5 mm to about 25 mm.

18. The absorbent article as claimed in clause 11, characterized in that the central bending axis includes a region of less dense absorbent which imparts to the absorbent core a preference for acquiring an upward convex configuration when lateral compressive forces are exerted on said core absorbent.

19. The absorbent article as claimed in clause 11, characterized in that said absorbent article assumes a "used pad" configuration when used.

20. The absorbent article as claimed in clause 11, characterized in that said absorbent article assumes an "A" configuration when used.

21. The absorbent article as claimed in clause 11, characterized in that said absorbent article assumes a "pant liner" configuration when worn.

22. The absorbent article as claimed in clause 11, further characterized by a transfer layer placed between the cover and the absorbent core.

23. An absorbent core having a body facing surface and a predetermined length and thickness comprising a central longitudinal bending axis which extends virtually the length thereof and at least partially divides said absorbent core into the first and second members each of said members has an outer limit, said first member has a second axis of flexure, and said second member has a third axis of flexure, said absorbent core includes longitudinal third and fourth absorbent members positioned laterally on one side but spaced of the outer limit of said first and second members by a distance virtually equal to said thickness so that, when the absorbent core is subjected to lateral compressive forces, said absorbent core generally acquires a "W" shaped configuration.

24. The absorbent core as claimed in clause 23, characterized in that said second and third bending axes each include a longitudinal cut extending through about 75% of said respective member, and wherein said cut is placed laterally from the central longitudinal bending axis by a distance of about 5 mm to about 25 mm. In testimony of which I sign the present in Mexico, D.F., on June 9, 1995. KIMBERLY-CLARK CORPORATION Attorney.