MXPA00000055A - Disposable absorbent articles having an increased fit for the body anatomy - Google Patents

Abstract

A tridimensional disposable absorbent article having a body facing surface and a garment facing surface, a longitudinal symmetry plane, a front end edge and a rear end edge, and comprising a liquid pervious topsheet, a backsheet joined to said topsheet and an absorbent core intermediate the backsheet and the topsheet. The absorbent core has a front portion, a central portion and a rear portion, and comprises a longitudinally oriented ridge in the central and rear portion having a profile that provides for an increased body fit.

Description

DISPOSABLE ABSORBENT ARTICLES THAT HAVE A ADJUSTMENT INCREASED BY THE USER'S ANATOMY FIELD OF THE INVENTION The present invention relates to disposable absorbent articles. Disposable absorbent articles are considered as absorbent devices designed to be used externally of the body by a user and to receive fluids discharged from the body. In particular, the present invention relates to disposable absorbent sanitary napkins, menstruation pads, incontinence inserts, and panty liners that are capable of providing increased fit for the body and reduced leakage by equalizing the non-planar surfaces and the nonlinear grooves of the body. body. Disposable absorbent articles comprise an absorbent core having a front portion, a central portion and a rear portion, and comprise a longitudinally oriented edge at the central and rear portions having a declining slope backward.

BACKGROUND OF THE INVENTION In its basic form, the disposable absorbent articles comprise an absorbent core interposed between a permeable element that contacts the body (alternatively referred to as an upper sheet or an envelope) and an impermeable protective barrier (alternatively referred to as a back sheet). Of course, the absorbent element must receive and contain the fluids discharged from the body. The element that makes contact with the body must provide comfortable contact and dry feeling with the body surfaces, while allowing free passage of fluids in the absorbent element. The lining barrier must prevent fluids, which are expelled or escaping from the absorbent element, from soiling the user's garment. The major disadvantages of known absorbent articles to be used externally of the body, eg, dripping, wet / dirty feeling, discomfort, refer to the poor fit to the body achieved by these articles which are substantially flat before being used and then must be squeezed or bend in the correct way to follow the surface of the body or, alternatively, they are molded before use, but anyway they need to improve in order to obtain a better fit with the complex shapes of the user's anatomy. In addition, most known disposable absorbent articles should be applied to the panty, and are typically fixed with an adhesive, and this does not facilitate a good fit with the anatomy of the body, also due to differences in usage habits and styles. of panties. With respect to sanitary napkins, several attempts have been made in order to provide these articles with the ability to conform to the anatomy of the body. Sanitary napkins that conform to the body are well known in the art, both those that are flat before being used, and that are intended to form or mold in use to equal the user's anatomy, as well as those that are formed before use. Sanitary napkins which are generally bowl-shaped or pot-shaped and which are intended to catch menstruation as it runs or drips from the vaginal orifice are known, such as those disclosed in for example U.S. Patent No. 4,655,759, entitled "Reduced leakage menstrual pad with built-in fold lines", Romans-Hess et al., Issued April 7, 1987. A second known type of design includes sanitary napkins that are raised up or with humps in their middle portions to be near or in contact with the pudendal region when worn, such as for example those described in U.S. Patent No. 4,701,177, entitled "Three-dimensional shaped feminine pad with narrow absorbent center and winged edges", Ellis et al. Issued on October 20, 1987. Although these types of sanitary napkins provide some measure of success by absorbing and containing body exudates, these failures in providing a sanitary towel that conforms closely to and adjusts to the anatomy of the body of the pudendal region. An attempt to increase the fitness capacity of the sanitary napkin has been to combine both the bowl shape and the hump shape in the article itself, typically achieving a sanitary napkin having a concave front portion combined with a raised back portion. , in order to better adjust the variations in the anatomy in the longitudinal direction. An example of this type of approach is European patent EP-B-162451, in which an anatomically conformable labial pad is disclosed, having a substantially planar frontal portion and a rear portion comprising a longitudinally oriented projection. The labial pad is instead short, as it is intended for partial disposition within a user's vestibule, with a rear projection that has to be inserted between the labia majora in order to obstruct the vestibule. A somewhat similar type of structure, although only for external arrangement, is described in European patent EP-B-302523, in which a sanitary napkin comprising a substantially flat or concave front portion intended to externally cover the area is disclosed. of the pubic mound, and a raised peak longitudinally oriented in the rear portion that must fit and mold to the inverted V shape of the back portion of the lips. Although this type of structure provides the sanitary towel with some adjustment capacity and conforms to the anatomy of the user, this can not yet actually adjust to the various complex body shapes of the female anatomy comprising non-linear grooves and non-planar surfaces. . The sanitary towel of EP-B-302523 is provided with its three-dimensional shape by bending or molding an initially flat structure; this involves for example that the raised peak in the rear portion has a rectilinear profile when viewed in the side view, and therefore fails to properly shape the corresponding non-linear profile of the anatomy as seen in the longitudinal direction . A thin absorbent article, particularly a sanitary napkin, incorporating a three-dimensional structure with a concave front portion and a raised back portion is described in International Patent Application WO 93/15700. The article is particularly suitable for being packaged in a very compact form, but the resulting three-dimensional structure is not very likely to conform to the user's anatomy, thereby providing comfort and body fit. It is therefore an object of the present invention to provide a three-dimensional disposable absorbent article, particularly a sanitary napkin, having a structure capable of forming the various complex body shapes of the female anatomy comprising non-linear grooves and non-linear surfaces. flat, in order to provide increased body comfort and fit, and reduced drip. It is another object of the present invention to provide said article, which is also thin. It is a further object of the present invention to provide a disposable absorbent article that can be applied directly to the wearer's body, preferably without the need for fastening means for securing the absorbent article to the undergarment.

BRIEF DESCRIPTION OF THE INVENTION The present invention relates to a three-dimensional disposable absorbent article having a body-facing surface and a garment-facing surface, a plane of longitudinal symmetry, a front end edge and a trailing end edge, comprising a permeable top sheet to liquid, a backsheet attached to the topsheet and an absorbent core intermediate between the topsheet and the backsheet, the absorbent core comprising a front portion, a central portion and a back portion. The surface that faces the body defines a line formed by the intersection of the surface that looks at the body with the plane of symmetry, the line being present in a system of the Cartesian plane x and within the plane of symmetry, with the x axis defined by the two points of intersection of the plane of longitudinal symmetry with the front end edge and the rear end edge, and with the surface facing the body facing positive values and, the line with a first derivative with respect to said Cartesian system xy. The article is such that at least one value of the first derivative of the line in the central portion of the absorbent core is greater than at least one value of the first derivative of the line in the rear portion of the absorbent core.

BRIEF DESCRIPTION OF THE DRAWINGS Although the specification concludes with claims that point out in particular and distinctly claim the present invention, it is believed that the present invention will be better understood from the following description along with the following drawings: Figure 1 is a perspective view of an embodiment of a sanitary napkin according to the present invention; Figure 2 is a cross-sectional view of the sanitary napkin of Figure 1 on line 2-2; Figure 3 is a top view of the sanitary napkin of Figure 1; Figure 4 is a curve taken from an anatomical section of the body of a user, schematically representing the central non-linear groove of the female anatomy as seen in the lateral direction; Figures 5a, 5b and 5c are cross-sectional views of the sanitary napkin of Figure 1 on lines 5a-5a, 5b-5b and 5c-5c, respectively; DETAILED DESCRIPTION OF THE INVENTION This invention relates to disposable absorbent articles that exhibit absorption for body fluids, protection of the wearer's garments from soiling, and improved physical comfort for the wearer, which are also easy to produce and pack and which exhibit increased fit to the body and better conformability to the anatomy of the user being provided with a three-dimensional structure capable of equalizing the non-linear grooves and the non-planar surfaces of the female body. Disposable absorbent articles are described below with reference to a sanitary napkin or menstruation pad. The term "sanitary napkin", as used herein, refers to an article that women use externally of the body and adjacent to the pudendal region and that must absorb and contain various body fluids that are discharged from the body (eg, example, vaginal discharges, menstruation and / or urine) and that should be discarded after a single use. However, it should be understood that the present invention is also applicable to other feminine hygiene or menstruation products such as panty liners, or other absorbent articles such as incontinence pads, and the like. The term "use", as used herein, refers to the period that begins when the absorbent article actually comes into contact with the user's anatomy. The terms "attached" or "fixed", as used herein, encompass configurations whereby a first member connects directly to a second member and configurations whereby a first member indirectly connects to a second member by connecting the first member to intermediate members who in turn connect to the second member.

As used herein, the term "pudendo (a)" refers to the externally visible female genitalia and is limited to the labia majora, labia minora, clitoris, and vestibule. Figure 1 is a perspective view of a sanitary napkin 20 of the present invention with its three-dimensional structure before use, with most of the portion of the sanitary napkin 20 facing or contacting the user, facing towards the observer. By saying "before use", it is meant that the preferred sanitary napkin of the present invention is provided with a three-dimensional structure before it is actually used. However, the sanitary napkin can be packaged in a folded planar configuration, subsequently unfolded to obtain the three-dimensional shape just before use. As best shown in Figure 2, the sanitary napkin 20 comprises a liquid permeable upper sheet 22, a liquid impermeable backsheet 23 joined with the upper sheet 22, and an absorbent core 24 positioned between the upper sheet 22 and the sheet rear 23. The sanitary napkin 20 has two surfaces, a surface that faces or makes contact with the body 20a and a surface that faces or makes contact with the garment 20b. The surface contacting the body 20a should be used adjacent the user's body, while the garment surface 20b is on the opposite side and should be directed towards the underwear when the sanitary napkin 20 is used, for example, against the same. Corresponding body and garment facing surfaces can also be identified in each individual layer constituting the sanitary napkin 20, for example, in the absorbent core 24. The sanitary napkin 20 has a plane of longitudinal symmetry S. The term "longitudinal", as used herein, it refers to a line, axis or direction in the sanitary napkin 20 that is generally aligned with (eg, approximately parallel to) a vertical plane that divides a user standing in halves of the left body and right when using the sanitary napkin 20. The plane of symmetry S of the sanitary napkin 20 substantially corresponds to this vertical plane that divides the user standing up. Although it is preferred that the sanitary napkin 20 be divided exactly by the plane of longitudinal symmetry S into two symmetrically equal halves, it is not excluded that the two halves are not specular. The term "transverse", as used herein, refers to a direction that is generally perpendicular to the plane of longitudinal symmetry S. the term "longitudinally oriented" refers to a direction, as seen in plan view, included within ± 45 degrees, of the plane of longitudinal symmetry S; the term "transversely oriented" refers similarly to any other direction, as seen in plan view. The terms "front" and "rear", as used herein, refer to portions that face the front and back of the user's body, respectively, when the sanitary napkin 20 is used. The sanitary napkin 20 has a periphery 30, which is defined by the outer edges of the sanitary napkin 20. The longitudinal edges 31 of the sanitary napkin 20 are aligned with the longitudinal symmetry plane S, and the end edges of the sanitary napkin 20 comprise a front end edge 32a and a rear end edge 32b. The absorbent core 24 of the sanitary napkin has a front portion 40, a central portion 42 and a rear portion 44, each preferably corresponding to approximately one third of the total length of the absorbent core 24. Also the front, middle and rear portions , corresponding, can be identified respectively in the sanitary napkin 20. The sanitary napkin 20 of the present invention is three-dimensional, since it is provided before being used with a three-dimensional structure that must match the complex body shapes of the female anatomy. The three-dimensional structure preferably has a structural three-dimensionality, by "structural tridimensionality" it is meant that the structure can not be completely flattened on a flat surface while maintaining its integrity, that is, without crushing or crushing in any case. In other words, the three-dimensional structure can not be achieved by simply folding or folding an initially flat article, but it is inherently due to the absorbent article in accordance with the present invention. The three-dimensional sanitary towel 20 of the present invention preferably has a substantially constant thickness, which is more preferably less than 5 mm; therefore, the sanitary napkin can be considered the thin type. While the topsheet, backsheet and absorbent core can be assembled in a variety of well-known configurations (including so-called "tube" products or side flap products), Figure 1 shows a preferred embodiment of the sanitary napkin. wherein the topsheet 22 and the backsheet 23 have dimensions of length and width generally larger than those of the absorbent core 24. The topsheet 22 and the backsheet 23 extend beyond the edges of the absorbent core 24 to thus forming the periphery 30 of the sanitary napkin 20. The upper sheet 22 is comfortable, soft and non-irritating to the wearer's skin. In addition, the topsheet 22 is permeable to liquid, which allows the liquid (eg, menstruation and / or urine) to penetrate through its thickness. A suitable top sheet 22 can be manufactured from a wide scale of materials such as woven and nonwoven materials; polymeric materials such as open formed thermoplastic films, open plastic films, and hydroformed thermoplastic films; porous foams; cross-linked foams; crosslinked thermoplastic films; and thermoplastic fabrics. Suitable woven and nonwoven materials may be comprised of natural fibers (e.g., wood or cotton fibers), synthetic fibers (e.g., polymer fibers such as polyester, polypropylene or polyethylene fibers); or a combination of natural and synthetic fibers. A preferred top sheet comprises an open formed film. Open-formed films for the topsheet are preferred since they are permeable to body fluids and not yet absorbent and have a reduced tendency to allow liquids to re-pass and re-wet the wearer's skin. In this way, the surface of the formed film that is in contact with the body, remains dry, thus reducing dirt from the body and creating a more comfortable feeling for the user. Suitable formed films are described in the U.S. Patent. No. 3,929,135, issued to Thompson on December 30, 1975; Patent of E.U.A. No. 4,324,246, issued to Mullane et al. On April 13, 1982; Patent of E.U.A. No. 4,342,314, issued to Radel et al. On August 3, 1982; Patent of E.U.A. No. 4,463,045, issued to Ahr et al. On July 31, 1984; and Patent of E.U.A. No. 5,006,394, issued to Baird on April 9, 1991. A preferred top sheet for the absorbent article of the present invention is a formed film described in one or more of the above patents and marketed in sanitary napkins by The Procter & Gamble Company of Cincinnati, Ohio as "DRI-WEAVE". In a preferred embodiment of the present invention, the exposed body or surface of the formed top sheet of film is hydrophilic in order to aid in liquid transfer through the upper sheet faster than if the body surface were not hydrophilic, for thus decreasing the likelihood that the menstrual fluid will flow out of the upper sheet instead of flowing in and absorbed by the absorbent core. In a preferred embodiment, surfactant is incorporated into the polymeric materials of the formed film topsheet as described in U.S. Patent Application Serial No. 07 / 794,745, Aziz et al., Filed November 19, 1991. Alternatively, the body surface of the top sheet can be made hydrophilic by treating it with a surfactant such as described in the US Patent. 4,950,254. The absorbent core 24 may be any absorbent means that is capable of absorbing and retaining liquids (e.g., menstruation and / or urine). The absorbent core 24 can be manufactured in a wide variety of sizes and shapes (e.g., rectangular, oval, hourglass, asymmetric, etc.) and a wide variety of liquid absorbent materials commonly used in sanitary napkins and other absorbent articles such as wood pulp which is generally referred to as air felt. Examples of other suitable absorbent materials include cellulose filler, modified intertwined cellulose fibers (such as those described in US Patent No. 5,217,445, issued to Young et al. On June 8, 1993), capillary channel fibers (ie. , fibers having intra-fiber capillary channels such as those described in U.S. Patent No. 5,200,248, issued to Thompson et al. on April 6, 1993), absorbent foams (such as those described in U.S. Patent No. 5,260,345, issued to DesMarais et al. On November 9, 1993 and U.S. Patent No. 5,268,244, issued to DesMarais and others on December 7, 1993), thermally bonded air-laid materials (such as those described in the patent application of the United States Serial Number 08 / 141,156, entitled "Catamenial Absorbent Structures Having Thermally Bonded Layers for Improved Handling of Menstrual Fluids and Their Use in Catamenial Pads Having Improved Fit and Comfort "presented on behalf of Richards and others, October 21, 1993), absorbent sponges, synthetic fibers, polymeric fibers, polymer gel solidifying agents that form hydrogel, swamp moss, tissue including wraps and sheets of fabric, or any equivalent material or combinations of materials. Suitable absorbent cores comprising foams are described in European applications 0 598 833, 0 598 823 and 0 598 834. Suitable absorbent cores comprising sheets of tissue with particles of solidifying agents in a hydrogel-forming polymer gel comprised therein, describe in international patent applications WO 94/01069 and WO 95/17868. The configuration and construction of the absorbent core can also vary (for example, the absorbent core may have gauge zones that vary, for example, that are thicker in the center), hydrophilic gradients, superabsorbent gradients, or base weight acquisition zones of lower density and lower average; or may comprise one or more layers or structures. However, the total absorbent capacity of the absorbent core must be compatible with the leading design and the intended use of the sanitary napkin. In addition, the size and absorbent capacity of the absorbent core can be varied to accommodate different uses such as incontinence pads, pant liners, regular sanitary napkins, or sanitary napkins for the night.

Preferably, the absorbent articles of the present invention are sanitary napkins that are uniform in thickness. The backsheet 23 and the topsheet 22 are positioned adjacent to the garment facing surfaces 20b and the body facing surface 20a, respectively, of the absorbent core 24 and are preferably attached thereto and to each other by means of fixation (not shown) such as those well known in the art. For example, the backsheet 23 and / or the topsheet 22 can be secured to the absorbent core 24 or to each other by a uniform continuous layer of adhesive, a patterned adhesive layer, or an array of separate lines, spirals or patches of adhesive. adhesive. The adhesives that have been discovered are satisfactory, they are manufactured by H.B. Fuller Company of St. Paul, Minnesota under the designation HL-1258 or H-2031. The attachment means will preferably comprise an open-pattern network of filaments of adhesive as described in US Pat. No. 4,573,986, entitled "Disposable Waste-Containment Garment", which was issued to Minetola et al. On March 4, 1986. A fixing means as an example of an open-pattern network of adhesive filaments comprises several lines of adhesive filaments wound in a spiral pattern as illustrated by the apparatus and methods shown in the US Patent 3,911,173, issued to Sprague, Jr., on October 7, 1975; the Patent of E.U.A. 4,785,996, issued to Zieker et al. On November 22, 1978; and the U.S. Patent. 4,842,666, issued to Werenicz on June 27, 1989. Alternatively, the fixing means may comprise heat links, pressure links, ultrasonic links, dynamic mechanical links, or any other suitable means of attachment or combinations of these fixing means as they are known in the art. The backsheet 23 is impervious to liquids (e.g., menstruation and / or urine) and is preferably fabricated from a thin plastic film, although other flexible liquid impervious materials may also be used. In use, the backsheet 23 is interposed between the absorbent core 24 and the wearer's underwear. The function of the backsheet 23 is to prevent exudates that can be expelled from or inadvertently passing the absorbent core 24, contacting or soiling the wearer's underwear. In this manner, the backsheet 23 may comprise a woven or non-woven material, polymeric films such as polyethylene or polypropylene thermoplastic films, or mixed-body materials such as a film-coated nonwoven material. Preferably, the backsheet is a polyethylene film having a thickness of about 0.012 mm to about 0.015 mm. Exemplary polyethylene films are manufactured by Clopay Corporation of Cincinnati, Ohio, under the designation P18-0401 and by Ethyl Corporation, Visqueen Division, of Terre Haute, Indiana, under the designation XP-39385. The backsheet 23 is preferably embossed and / or mat finished to provide an appearance more to the type of clothing. In addition, the backsheet 23 can allow vapors from the absorbent core 24 to escape (i.e., can breathe) even preventing the exudates from passing through the backsheet 23.

As shown in FIGS. 1 and 2, the sanitary napkin 20 has before it is used a three-dimensional structure with a longitudinally oriented seam 50 in the central and rear portions 42, 44 of the absorbent core 24, so that the intersection line 46 of the longitudinal symmetry plane S with the body-facing surface 20a has a slope that slopes backward, ie towards the rear end edge 32b, in the central portion 42 and in the rear portion 44 of the absorbent core 24. This is can be seen more clearly in Figure 2, where the longitudinal sectional view of the sanitary napkin 20 shows the intersecting line 46 with its declining slope in the central and rear end portions 42, 44. The downward slope of said line of intersection 46 can be expressed mathematically if said line of intersection 46 is considered in a Cartesian system x and in the plane of symmetry S, where the x axis is defined by the two points of intersection of the longitudinal symmetry plane S with the front end edge 32a and the trailing end edge 32b of the sanitary napkin 20, which corresponds substantially to the points indicated by numerals 32a and 32b in the cross-sectional view of the sanitary napkin 20 illustrated in FIG. Figure 2, and wherein the surface facing the body 20a looks towards positive values y. With respect to this system of axes, one can form the first derivative of the line of intersection 46. According to the present invention, the first derivative of this line 46 in the longitudinal direction has at least one value that is larger in the central portion 42 of the absorbent core 24 having at least one value at the rear portion 44 of the absorbent core 24. This includes the preferred case, illustrated in Figures 1 and 2, wherein the intersection line 46 is always inclined toward the rear end edge 32b with two different slopes in the central portion 42 and in the rear portion 44, and also alternative embodiments wherein, for example, the intersection line 46 slopes upward in the central portion 42 and downward in the portion rear 44. The consecutive values of the first derivative of the intersecting line 46 can fall continuously towards the rear end edge 32b, which implies that the line of interest section 46 has a curved profile with a continuously declining slope, or, alternatively, the first derivative may assume different discrete values over the length of intersecting line 46. For example, it may be constant in the case of the embodiment illustrated in Figures 1 and 2, wherein the intersecting line 46 is formed by two substantially rectilinear portions having constant slopes, with a change in slope at a point 48 of the intersection line 46 placed where the central portion 42 of the absorbent core 24 fuses the back portion 44. An intersecting line 46 with the profile described above, provides the sanitary napkin 20 of the present invention with a longitudinally oriented seam 50 in the central and rear portions 42, 44 of the absorbent core 24 having a longitudinal non-linear profile that must match in use the central non-linear groove of the female anatomy that extends from the lips ores to the perineum and in the gluteal groove, and with approximately the shape schematically indicated in the corresponding central and rear portions 42 ', 44' of the curve G illustrated in figure 4, where the equalization profile of a intersecting line 46 in a sanitary napkin illustrated in Figures 1 and 3. The profile of the longitudinally oriented seam 50 as defined by the intersecting line 46 with its slope going down backwards, can provide the sanitary napkin 20 with an adjustment to the improved user's body. In the preferred embodiment illustrated in FIG. 1, when facing backward, the front portion of the seam 50, with a substantially constant slope, should adjust the groove between the labia majora. The subsequent portion of the seam 50 that fills the central and rear portions 42, 44 of the absorbent core 24, with its change in slope, has a profile that is capable of equalizing in use the concave portion downwardly of the central nonlinear slot of the female anatomy in the region that goes from the back of the labia to the perineum, in order to achieve continuous contact with the body. This provides better comfort and more effective interception of fluids as the body releases them. Finally, the rear portion of the longitudinally oriented seam 50, still belonging to the rear portion 44 of the absorbent core 24 and with a constant slope in the embodiment of FIG. 1, it should extend between the buttocks, but due to its lighter slope, compared to the front portion of the seam, it is able to make contact with the body without causing any tension between the anatomy and this portion of the sanitary napkin, which in turn, it would cause discomfort, and / or prevent the substantially continuous contact desired between the seam 50 and the user's anatomy over the entire length of the non-linear groove extending from the labia majora to the gluteal groove. In other words, a seam 50 with a profile having a slope that slopes backwards, can obtain more in its non-linear groove, as indicated schematically in Figure 4. The seam 50 with the profile indicated by the line 46 in fact it is able to follow the profile of the groove, indicated by the curve G, by extending beyond the line, indicated by the dotted line in figure 4, which connects two points on the central groove of the surface of the body where the Sanitary towel makes contact with the anatomy, for example, the two points where the sanitary napkin makes contact with the body in correspondence of the front and rear portions of the seam. A seam formed with a linear profile as those known in the art can not extend beyond this line, since said seam corresponds substantially to this line, and thus can not provide continuous contact with the body over the entire length of the line. sewing In the embodiment of the present invention illustrated in Figures 1 and 2, the three-dimensional sanitary towel 20 preferably has a low constant thickness that is less than 5 mm, wherein the three-dimensional structure is provided without the use of humps or regions of different thickness, and is an inherent aspect of the sanitary napkin 20, rather than an aggregate aspect, achieved, for example, by bending or joining an initially planar structure.

As shown in the embodiment of the present invention illustrated in FIGS. 1 and 2, the front portion 40 of the absorbent core 24 is preferably concave upward, in order to better conform to the user's anatomy in the pubic region.

The sanitary napkin 20 illustrated in Figures 1 and 2 shows a particularly preferred configuration for the front, central and rear regions 40, 42 and 44 of the absorbent core 24. As seen in cross-section, the front, middle and rear regions of the absorbent core 24 respectively have a V-shape, a W-shape, and an inverted V-shape, as best shown in Figures 5a, 5b and 5c, are illustrated in Figure 1 5b-5b and 5c-5c, respectively . These different shapes provide the sanitary napkin 20 with more capacity to conform to the user's anatomy in a direction substantially perpendicular to the plane of symmetry S already defined. The V shape of the front portion 40 and the inverted V shape of the rear portion 44 are fused together gradually in the central portion 42, where the resulting shape W is predisposed to fit in the area of the labia majora and peri . In use, the longitudinally oriented seam 50 must adjust the longitudinal central groove as described above, while the side portions 52 bent upward may equal the thigh wrinkles, ie, the two grooves that are formed between the body and the body. the legs, typically in the area where the elastic of the panties makes contact with the body.

In the preferred embodiment of the present invention illustrated in Figures 1 and 2, the sanitary napkin 20 is provided with an increased capacity to conform to the anatomy of the user than that given simply by the known differentiated transverse shape of the different portions of the absorbent core. 24. The three-dimensional structure of the sanitary napkin 20 before being used, is such that the width of the angle? of the inverted V-shaped portion increases towards the trailing end edge 32b of the sanitary napkin 20 starting from a minimum preferred value to a position corresponding to the fusion of the rear portion 44 with the central portion 42 of the absorbent core 24, in where it substantially corresponds to the angle ß of the central inverted V-shaped part of the W-shaped central portion 42, which in turn is substantially constant over the entire length of this portion 42. Therefore, the rear portion of the seam 50, typically placed in use between the buttocks, its inverted V shape can be more easily extended during the use of the product without being restricted, in order to provide the sanitary napkin with a better adaptation to the user's configuration. A similar feature is preferably provided in the V-shaped front portion 40 of the absorbent core 24, wherein the angle A of the V increases its width toward the front end edge 32a of the sanitary napkin 20 from a minimum preferred value in a point corresponding to the fusion of the front portion 40 with the central portion 42. This would allow the portion of the sanitary napkin 20 that is closer to the front end edge 32a to be more easily flattened in the transverse direction during use, in order to accommodate the relatively flat front of the pubis, at the same time providing a global concave shape to effectively follow the surface of the pubis. The angles of the V-shaped central portion 40 and / or the inverted V-shaped rear portion 44 of the absorbent core 24, and consequently of the entire sanitary napkin 20, can therefore increase towards respective end edges 32a and / or 32b to values of about 180 °, in order to better accommodate the user's anatomy without inducing any substantial tension in the structure, thus providing a better fit and comfort. The preferred aspect of the angles increasing towards respective extreme edges in the inverted V and V-shaped portions, is achieved by giving the front portion 40 and / or the rear portion 44 of the absorbent core 24 a bowl-shaped structure with any means known to one skilled in the art. For example, in the sanitary napkin 20 of the present invention illustrated in FIGS. 1 and 2, this is achieved by cutting a narrow V-shaped portion of material centered over the longitudinal centerline of the initially flat front portion 40 and back portion. 44 of the absorbent core 24, and of the topsheet 22 and the backsheet 23, and with substantially the same length of the front portion 40 and of the back portion 44, and then join the cut edges with known means, for example, by thermal link, on the connecting lines identified as 52 and 54 in Figure 3. The final three-dimensional structure illustrated in Figures 1 and 2 is then achieved by properly folding the non-planar sanitary napkin 20, for example, over the lines of preferential bending, formed in the absorbent core 24 by means of, for example, partial enhancements or cuts, such as the highlights 56 in Figure 3, as can be determined by the person skilled in the art. AC. The presence of this preferred aspect in the sanitary napkin of the present invention illustrated in FIGS. 1 and 2, can be ensured by transversally folding the sanitary napkin 20 in order to over impose the front portion 40 or the rear portion 44 of the absorbent core on the central portion 42 on a bent line approximately in the unfolded sanitary napkin corresponds to a line separating, respectively, the front portion 40 or the rear portion 44 of the central portion 42; in both cases, the fold line will show an angle instead of being rectilinear In an alternative embodiment of the present invention, a three-dimensional shape similar to that illustrated in Figures 1 to 5c can also be achieved by having in a disposable absorbent article an elastic insert with the desired shape, for example, between the back sheet and the absorbent core. The insert may comprise, for example, only in the central and rear portions of the absorbent core, where the seam with the desired profile must be provided, or it may extend over the entire length of the absorbent article, in order to provide its full shape . The elastic insert can be made of any suitable known material, for example, absorbent or non-absorbent material, and can be produced, for example, by thermofixing to obtain the desired three-dimensional shape, preferably with a constant thickness. The insert can completely provide the three-dimensional structure, or it can alternatively contribute to creating and maintaining said structure in an already formed absorbent article. In a preferred embodiment of the present invention, the three-dimensional absorbent article, for example, sanitary napkin 20, is applied by the wearer directly to the body. The three-dimensional structure of the absorbent article and its ability to conform and adjust to the anatomy of the user may allow the article to remain in place during use possibly without the need for additional means intended to secure the article to an undergarment. Moreover, the front portion of the seam can be easily identified in the sanitary napkin, which makes it possible to use as a reference to direct the sanitary napkin towards its optimum position in the body. Alternatively, the absorbent article of the present invention may also be provided with a panty fastening means, which provides the means for securing the article to the undergarment. For example, the fastening means of the panty may comprise a mechanical fastener such as the hook and curl fasteners as sold under the tradename VELCRO, snaps or fasteners. Alternatively, the absorbent article is fastened to the undergarment by means of the panty fastening adhesive on the backsheet 23. The panty fastening adhesive provides a means for securing the absorbent article to the panty and preferably a Medium for securing the absorbent article when staining for the fold and wrapping of the package for convenient disposal. Typically, at least a portion of the garment facing surface of the backsheet 23, preferably a portion corresponding to the front portion of the absorbent core 24 only, is coated with adhesive to form the panty fastening adhesive. Any adhesive or glue used in the art for these purposes can be used for the fastening adhesive of the pantyhose herein. Pressure sensitive adhesives are more preferred. Suitable adhesives include Centrury A-305-IV manufactured by Century Adhesives Corporation of Columbus, Ohio, and Instant LOK 34-2823 manufactured by National Starch and Chemical Company of Bridgewater, New Jersey, 3 Sigma 3153, manufactured by 3 Sigma and Fuller H -2238ZP manufactured by H: B. Fuller Co. The panty fastening adhesive can typically be applied to the backsheet by slot or spray coating in various distribution patterns, such as, for example, continuous or discontinuous strips, intermittent dots, spirals with random patterns. The panty fastening adhesive is typically protected with a removable release paper or film in order to prevent the adhesive from drying or adhering to a different surface of the panty. Any commercially available release paper or film can be used. Suitable examples include BL 30MG-A SILOX El / O and BL 30 MG-A SILOX 4 P / O available from Akrosil Corporation. The absorbent articles of the present invention, particularly the sanitary material 20, have a length which preferably varies between the typical values commonly used for the different sizes of said sanitary articles intended for the substantially external disposition adjacent to the wearer's body. Particularly, the central and rear portions 42 and 44 of the absorbent core 24 preferably do not have a length that is less than the total maximum length of the major lips of an average user. Other alternative means for providing a disposable absorbent article of the preferred three-dimensional structure, other than cutting, joining and pasting, as already explained, can be achieved by providing an absorbent article with an elastic, extensible portion, which can be formed to produce a structure equivalent to preferred structure, for example, by stretching it in the transverse direction in the central and rear portions of the absorbent core. The three-dimensional absorbent article of the present invention may further comprise an odor control material for controlling unpleasant odors associated with absorbed body fluids. Any known odor control agent or any combination thereof that may be included in a disposable absorbent article, including other materials such as binders and / or substrates, may be comprised in the absorbent article of the present invention as the control material of the present invention. odor. The odor control material can be incorporated into the absorbent article by methods known in the art, for example, laminate or in the absorbent core or mixed with the absorbent core. In an alternative embodiment of the present invention, the three-dimensional absorbent article may have two fins (not shown) each of which is adjacent to and extends laterally from the lateral edge of the absorbent core. The flaps are configured to cover the edges of the wearer's panties in the crotch region, so that the flaps are disposed between the edges of the wearer's panties and the wearer's thighs. The fins serve at least two purposes. First, the fins serve to prevent the body and the user's panties from becoming soiled by menstrual fluid, preferably by forming a double wall barrier on the edges of the pantyhose. Second, the fins are preferably provided with fastening means on their garment facing surface such that the fins can fold back under the panty and be fixed to the side facing the garment of the panty. In this way, the fins serve to keep the sanitary napkin properly placed in the pantyhose. The fins can be constructed of various materials including materials used for the topsheet 22, backsheet 23, combinations thereof, and can be a sheet with fabric in the center. In addition, the fins can be an element fixed to the main body of the three-dimensional absorbent article or can comprise extensions of the upper sheet 22 and / or back sheet 23. However, it is recommended that the fins have a liquid-impermeable back sheet to prevent bodily fluids that reach the fins dirty the edges of the user's panties. Preferred fins that are suitable or can be adapted to the three-dimensional absorbent article of the present invention are described in the U.S. Patent. No. 4,687,478, issued to Van Tilburg on August 18, 1987; Patent of E.U.A. No. 4,589,876, issued to Van Tilburg on May 20, 1986; and Patent of E.U.A. No. 4,608,047, issued to Mattingly on August 26, 1986. Optionally, the three-dimensional absorbent article may comprise components that naturally surround the sides of a wearer's panties. Sanitary napkins having components that naturally surround the sides of a wearer's panties suitable for use with the three-dimensional absorbent article of the present invention are described in the co-pending U.S. Patent application. Serial No. 08 / 096,121 entitled "Absorbent Article having Panty Covering Components that Naturally Wrap the Sides of Panties", filed July 22, 1993, in the name of Lavash et al., And patent application of E.U.A. Serial Number 08 / 277,733 entitled "Absorbent Articles Having Undercover Covering Components with Zones of Extensibility", filed July 20, 1994, in the name of Weinberger and others. In other embodiments of the present invention, the three-dimensional absorbent article may also comprise additional elements, such as an acquisition layer or a secondary topsheet positioned between the topsheet 22 and the absorbent core 24 or, alternatively, at any other suitable position.

Although the disposable absorbent article of the present invention has been described with reference to a sanitary napkin, it can be beneficially used in the context of other disposable absorbent articles such as panty-hose and incontinence articles. The absorbent article disposable in this way can have all those characteristics and parts that are typical for products in the context of their intended use.

Claims (10)

RECIPE N DI CAC IO N ES

1 . A three-dimensional disposable absorbent article having a body-facing surface and a garment facing surface, a longitudinal symmetry plane, a front end edge and a trailing end edge, and comprising a liquid-permeable top sheet, a sheet posterior joined to the upper sheet and an intermediate absorbent core between the upper sheet and the back sheet, the absorbent core having a front portion, a central portion and a rear portion, the surface facing the body defining a line formed by the intersection of the surface that looks at the body with the plane of symmetry, the line being present in a Cartesian system xy within the plane of symmetry, with the x axis defined by the two points of intersection of the plane of longitudinal symmetry with the front end edge and the end edge, and with the surface facing the body looking towards positive values and, the line with a first derivative with resp ect to said Cartesian system xy, the article being characterized in that at least one value of the first derivative of the line in the central portion of the absorbent core is greater than at least one value of the first derivative of the line in the rear portion of the absorbent core .

2. A disposable absorbent article according to claim 1, further characterized in that all the values of said first derivative in the central portion are greater than the values of said first derivative in the rear portion.

3. A disposable absorbent article according to any of claims 1 or 2, further characterized in that the consecutive values of said first derivative in the central and rear portions continuously decrease toward the rear end edge.

4. A disposable absorbent article according to claim 1 or 2, further characterized in that said first derivative is constant in either said central portion or said rear portion, or both.

5. A disposable absorbent article according to any preceding claim, further characterized in that said front portion is concave upwardly.

6. A disposable absorbent article according to any preceding claim, further characterized in that the cross section of said article at the front portion is of V-shape defining an angle "a", said central portion being W-shaped defining an angle β, and in said rear portion it is inverted V-shaped defining an angle?.

7. A disposable absorbent article according to claim 6, further characterized in that the angle a of the V in said front portion increases towards the front end edge.

8. A disposable absorbent article according to claim 6 or 7, further characterized in that the angle? of the inverted V in the rear portion increases towards said rear end edge. A disposable absorbent article according to any preceding claim, further characterized in that the disposable absorbent article is provided with a structural three dimensionality, wherein said article can not be completely flattened on a flat surface while maintaining its integrity. A disposable absorbent article according to any preceding claim, further characterized in that said disposable absorbent article is a sanitary napkin or a panty protector and said article has a constant thickness of less than 5 mm.