MXPA99006222A - Sanitary napkin having stabilizing members in the end regions - Google Patents

Abstract

The present invention provides an absorbent article preferably being a sanitary napkin that comprises a longitudinal centerline, a transverse centerline, a pair of longitudinal edges, two end edges, a first end region extending from one of the end edges toward the transverse centerline, and a second end region extending from the other end edge toward the transverse centerline. Also, there is a central region positioned between the first and second end regions. The sanitary napkin further comprises a first surface, a second surface that is faced opposite to the first surface wherein the flexure-resistance of the sanitary napkin as measured through the first and second end regions is greater than the flexure-resistance of the sanitary napkin as measured through the central region.

Description

SANITARY TOWEL THAT HAS STABILIZING MEMBERS IN THE EXTREME REGIONS FIELD OF THE INVENTION The present invention is a sanitary napkin comprising end regions and preferably end edges that provide resistance to excess winding and ends of the article through the use of the stabilizing members therein.

BACKGROUND OF THE INVENTION The present invention relates to absorbent articles such as sanitary napkins, pantiliners, and incontinence pads that are designed to absorb and retain liquid and other discharge from the human body, and to prevent staining of the body and clothing. The present invention is particularly preferred with sanitary napkins having reduced top coiling in their end regions, particularly their end edges. Disposable absorbent articles are designed to contain exudates from the body and to prevent exudates from the body from staining clothing and adjacent undergarments. In this way, numerous improvements have been directed toward providing better containment of these exudates within the sanitary napkin and reducing the occurrence of staining of the used garments over the sanitary napkin. The staining of the garments resulting from the rolling over of the end edges of the sanitary napkin is particularly a problem with the catamenial products. Spotting on the end edges is caused by a lack or lack of stability in the end regions and / or on the end edges of a pad. It is therefore desirable to provide a sanitary napkin having a limited range of motion at its ends to prevent staining caused by excessive rolling. Additionally, this restricted movement range will increase the conformability to the body of the pad in general. Additionally, excessive rolling of the end of the pad increases the level of discomfort or the ability to perceive the product by a user, excessive rolling reduces the effectiveness of the catamenial pad by reducing the effective length of the pad, which can thus increase the amount of fluid that can directly flow from a user to his underwear. There have been a number of recent efforts to provide catamenial pads with improved body shaping characteristics in order to improve the performance and against leaks of these products. In particular, sanitary napkins that are relatively thin and flexible have been developed to better shape the sanitary napkin for the wearer. Commercially successful sanitary napkins of this type are described in U.S. Patent No. 4,950,264 issued to Osborn on August 21, 1990 and U.S. Patent No. 5,009,653 issued to Osborn on April 23, 1991. Although These ultra-thin and flexible absorbent articles work very well, there remains a need to improve the performance of the staining of the ends of these products and further improve their adjustment characteristics. U.S. Patent Application Serial No. 08 / 665,595 entitled "Sanitary towel, flexible, generally thin, with inflexible center", filed June 18, 1996 by Osborn, discloses a sanitary napkin having a core region hardened central absorbent. Additionally, the towel comprises means resistant to bending in its longitudinal side regions. This application also states that this sanitary napkin has a resistance to bending as measured across the first and second end regions, which is less than the bending strength as measured at the center region. U.S. Patent No. 5,578,025 issued November 26, 1996 to May discloses a sanitary napkin having stabilizing members attached along its sides to reduce staining and improve fit. In a modality there, May describes a towel having stabilizing members that extend around the entire periphery of the sanitary napkin, ie, including the end edges. However, May does not disclose or suggest otherwise than having the stabilizing members or any type of absorbent and / or hardened member placed only in the end regions and / or the end edges of the sanitary napkin as in the embodiment of the sanitary napkin. applicant. The invention of May then refers to providing a fully hardened periphery and not only providing stiffness or inflexibility at the end edges. Although the sanitary napkins disclosed in the patents and applications of Osborn and May's application work very well, continuing the search for improved sanitary napkins, that is, sanitary napkins specifically designed to reduce excessive coiling at their ends. As the products have become progressively more flexible, it has been observed that there is a tendency for the products not to wind up above in their end regions and specifically on their end edges. This phenomenon of rolling over the end contributes to both staining and discomfort of use. Thus, it is an object of the present invention to provide a sanitary napkin here with stabilizing members in its end regions and / or end edges to reduce the tendency to wind over the product at its ends.

It is also an object of the present invention to provide unitary disposable sanitary napkins with end / performance regions for improved edge spotting. It is a further object of the present invention to provide the adjustment of these sanitary napkins during use, such that their surface better conforms to the corresponding shape of the human body. These and other objects of the present invention will be more readily apparent when considered with reference to the following description and when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE INVENTION Accordingly, the present invention provides absorbent article preferably being a sanitary napkin comprising a longitudinal center line, a transverse center line, a pair of longitudinal edges, two end edges, a first region extending from one of the end edges. towards the transverse center line, and a second end region extending from the opposite end edge towards the transverse center line. Also, here is a central region placed between the first and the second end regions. The sanitary napkin further comprises a first surface and a second surface that is opposite from the first surface. The flexural strength of the sanitary napkin as measured by the first and second end regions is greater than the sanitary napkin flexural strength as measured across the central region due to the stabilizing members. placed in the first and in the second end regions.

Preferably, the stabilizing members are placed immediately adjacent to each end edge. Generally, the sanitary napkin of the present invention comprises first and second end regions extending from and including the end edges. Each end region comprises approximately 1/10 to 1/3 of the length of the sanitary napkin starting from one end edge and moving towards the transverse center line. In one embodiment of the sanitary napkin of the present invention, the flexural strength of the first and second end regions is at least about 25% greater than the flexural strength of the central region and of the longitudinal edges. .

BRIEF DESCRIPTION OF THE DRAWINGS Although the description concludes with the claims pointing out in a particular manner, and claiming differently from the subject matter that is considered as a formant of the present invention, it is believed that the invention will be better understood from the following descriptions which are taken in combination with the accompanying drawings, in which similar designations are used to designate substantially identical elements, and in which: Figure 1 is a plan view of a preferred embodiment of the present invention having portions cut away to reveal the underlying structure, the external surface of the sanitary towel facing the observer; Figure 2 is a cross-sectional view of the embodiment in Figure 1; Figure 2A is a cross-sectional view of an alternative embodiment of the embodiment of Figure 2.

Figure 2B is a cross-sectional view of an alternate embodiment of the embodiment of Figure 2; Figure 3A is a plan view of a modality having stabilizing members of an alternating design; Figure 3B is a plan view of a modality having stabilizing members of an alternating design; Figure 3C is a plan view of a modality having stabilizing members of an alternating design; Figure 4 is a plan view of an alternative embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION As used herein, the term "absorbent article" refers to devices that absorb and contain exudates from the body, and more specifically, refers to devices that are placed against or close to the user's body to absorb and contain several exudates discharged from the body. As used herein, the term "sanitary napkin" or "towel" refers to an absorbent article that absorbs and contains body exudates, and more specifically refers to an absorbent article that is worn by women adjacent to the pudendal region. , generally external to the genitourinary region, and which is intended to absorb and contain the menstrual fluids and other vaginal discharges of the wearer's body (eg, menstruation blood and urine). The term "disposable" is used herein to describe absorbent articles that are not intended to be washed or otherwise restored or reused as an absorbent article (ie, they are intended to be discarded after a single use, and preferably , to be recycled, composted or otherwise arranged in an environmentally compatible manner), a "unitary" absorbent article refers to absorbent articles that are formed of separate parts joined together to form a coordinated entity, in such a manner that these do not require separate manipulated parts, such as a fastener and separate liners. A preferred embodiment of a unitary disposable absorbent article of the present invention is the catamenial pad, sanitary napkin 20 shown in Figure 1. Interlabial devices that reside partially inside and partially outside the wearer's vestibule are also within the scope of the present invention. invention. As used herein, the term "pudendal" refers to the externally visible female genital organs. However, it should be understood that the present invention is also applicable to other feminine hygiene pads or catamenial pads such as pantiliners or other absorbent articles, such as incontinence pads and the like. By the terms "resistance" or "flexural resistances" or "flexural strength or resistances", herein is meant the rigidity attributed to an element when the element is made to act on external forces, for example, a resistance to the bending of the stabilizing members against compressive, transverse forces. Figure 1 shows a preferred embodiment of the sanitary napkin 20 in which the topsheet 28 and the backsheet 30 have length and width dimensions generally greater than those of the absorbent core 32. The periphery defines the outer perimeter or, in other words, the edges of the sanitary napkin. The periphery comprises the longitudinal edges 38 and the end edges 40. A particularly preferred construction for sanitary napkin 20 is that described in U.S. Patent Nos. 4,950,264 and 5,009,653 both entitled "Flexible, Thin Sanitary Towel", issued to Osborn on August 21, 1990 and April 23, 1991, respectively. Both of these patents are incorporated herein by reference.

Figure 1 also shows the preferred stabilizing members 42, which are located primarily adjacent to each end edge 40. As seen in Figure 1, both of the end edges 40 preferably comprise at least one stabilizing member 42. In one embodiment, the end edges 40 may actually be formed by at least a portion of the stabilizing members 42. In another embodiment, the stabilizing members 42 they are positioned adjacent the end edges 40. These stabilizing members 42 provide rigidity at the end edges 40, such that excessive winding of the edges 40 is reduced. In addition, in a preferred embodiment of the present, the stabilizing members 42 can partially extending along a portion of the longitudinal edges 38, but remaining within the end regions 50 and 54. In some embodiments, it may be preferred that there be only one stabilizing member in an end region 50 or 54 of the sanitary napkin 20. Each stabilizing member 42 is preferably a separate member attached to the sanitary napkin 20 in one or more of the end regions 50, 54 (including end edges 40). The term "stabilizing member" refers to a stiffener element attached to the sanitary napkin 20 in one or more end regions 50 and / or 54 to increase the flexural strength, i.e. the stiffness of the end regions 50, 54. Note, the stabilizing members herein may be either discrete discrete elements attached to the sanitary napkin and / or elements formed from existing elements within the sanitary napkin, eg, elements formed from the absorbent core. , the top sheet, the back sheet, the acquisition layer, and the like. Some general ways of providing sanitary napkin 20 with hardened end regions 50, 54 or end edges 40 (hereinafter referred to as "end regions") include, but are not limited to: (1) folding any of the components that comprise the end regions / edges to create double, or greater, thicknesses of the same; (2) construct the end regions / edges out of several layers; (3) using hardening materials (4) changing the basis weight of the components comprising the end regions / edges; (5) placing additional components in the end regions / edges; (6) compressing or thermally bonding the absorbent core to harden the end regions or (7) any of the combinations of the foregoing. The sanitary napkin 20 has two central lines, a main longitudinal center line 102 and a main lateral or transverse center line 100. The term "longitudinal", as used herein, refers to a line, axis or direction in the plane of the sanitary napkin 20 which is generally aligned with a vertical plane that divides a wearer standing in left and right body halves when the sanitary napkin 20 is used. This includes a line, axis or direction that is bent, curved or otherwise way not strictly parallel to the vertical plane. The term "lateral" refers to the line, axis or direction generally perpendicular to the longitudinal direction and which is located within the plane of the sanitary napkin 20. The sanitary napkin has a longitudinal dimension running in the general direction of the central line main longitudinal 102 and a lateral dimension running in the general direction of the main lateral center line 100. The sanitary napkin is typically longer in the longitudinal dimension than in the lateral dimension. As shown in Figure 1, the sanitary napkin 10 is by understanding its structure, divided into three sections: a first end region 50, a second end region 54 opposite the first end region 50, and a region central region positioned between the first end region 50 and the second end region 54. For the embodiments herein, the stabilizing means 42 are relegated to the first and second end regions 50 and 54. The central region will preferably comprise the majority or all of the absorbent core 32. The embodiment herein is designed in such a way that the central region 52 will be more flexible, ie, compressible to the forces applied along the transverse axis. Conversely, the end regions 50, 54 are designed in such a way that they will be stiffer than the central region 52 against the applied transverse axial forces. These forces are very significantly applied by the thighs of the wearer, which push against the longitudinal edges 32 of the sanitary napkin 20. The absorbent core 32 can be any absorbent medium that is capable of absorbing or retaining the liquids (e.g., menses) and / or urine). As shown in Figure 1, the absorbent core 32 has a body surface, a garment surface, side edges, and end edges. The absorbent core 32 can be manufactured in a wide variety of sizes and shapes (e.g., rectangular, oval, hourglass, dog bone, asymmetric, etc.), and from a wide range of liquid absorbing materials commonly used in sanitary napkins and other absorbent articles, such as crushed wood pulp which is generally referred to as an air filter. Examples of other suitable absorbent materials include accreted cellulose wadding; meltblown polymers, including coform, chemically hardened, modified or crosslinked cellulosic fibers; synthetic fibers such as pleated polyester fibers, peat moss, tissue including tissue wraps and tissue laminates; absorbent foams; absorbent sponges, superabsorbent polymers; gelling absorbent materials; or any equivalent material or combinations of materials, or mixtures thereof. The configuration and construction of the absorbent core 32 can also be varied (for example, the absorbent core 32 can have zones of variable gauge (for example, profiled to be thicker in the center), hydrophilic gradients, superabsorbent gradients or acquisition zones. lower density and lower average basis weight; or may comprise one or more layers or structures). However, the total absorbent capacity of the absorbent core 32 must be compatible with the design load and intended use of the sanitary napkin 20. In addition, the size and absorbent capacity of the absorbent core 32 can be varied to encompass different uses such as incontinence pads, pantiliners, regular sanitary napkins or night sanitary napkins. Exemplary absorbent structures for use as the absorbent core 32 of the present invention are described in U.S. Patent No. 4,950,264 entitled "Thin, flexible sanitary towel", issued to Osborn on August 21, 1990; U.S. Patent No. 4,610,678 entitled "High Density Absorbing Structures", issued to Weisman et al. on September 9, 1986; U.S. Patent No. 4,834,735 entitled "High density absorbent members having acquisition zones of lower density and lower basis weight", issued to Alemay et al. on May 30, 1989; and European Patent Application No. 0 198 683, published October 22, 1986 in the name of Duenk et al. Each of these patents are incorporated herein by reference. The backsheet 30 and the backsheet 28 are positioned adjacent the garment surface and the body surface, respectively, of the absorbent core 32 and are preferably attached thereto and to each other by attachment means (not shown such as those well known in the art. For example, the backsheet 30 and / or the top sheet 28 can be secured to the absorbent core 32 or to each other by a uniform, continuous adhesive layer, a patterned adhesive layer or an array of lines, spirals or Separate adhesive spots Adhesives that have been found to be satisfactory are manufactured by HB 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 disclosed in U.S. Patent No. 4,573,986 entitled "Disposable Waste Containment Garment", which was issued to Minetola on Mar. 4 1986, and which is incorporated herein by reference. An exemplary joining means of an open-filament pattern network comprises several lines of adhesive filaments twisted in a spiral pattern as illustrated by the apparatus and method shown in the United States patent.

United No. 3,911, 173 issued to Sprague on October 7, 1975; U.S. Patent No. 4,785,996 issued to Zieker et al. on November 22, 1978; and in U.S. Patent No. 4,842,666 issued to Werenicz on June 27, 1989. Each of these patents is incorporated herein by reference. Alternatively the joining means may comprise heat bonds, pressure joints, ultrasonic joints, mechanical dynamic joints or any other suitable joining means or combinations of these joining means as is known in the art. The backsheet 30 is impervious to liquids (eg, menses and / or urine), and is preferably manufactured from a thin plastic film, although other flexible liquid impervious materials may also be used. As used herein, the term "flexible" refers to materials that are docile and that will readily conform to the shape and general contour of the human body. The backsheet 30 prevents the exudates absorbed and contained within the absorbent core 32 from moistening or wetting the articles that are in contact with the sanitary napkin 20 described herein, such as breeches, nightwear and undergarments. The backsheet 30 can thus comprise a woven or non-woven material, polymeric films such as polyethylene or polypropylene thermoplastic films, or composite 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 0.051 mm. Exemplary polyethylene films are manufactured by Clopay Corporation of Cincinnati, Ohio, under the designation P18-0401 and by Ethyl Corporation of Visqueen Division, of Terre Haute, Indiana, under the designation XP-39385. The backsheet is preferably embossed and / or finished without gloss to provide a more fabric-like appearance. In addition, the backsheet 30 can allow vapors from the absorbent core 32 to escape (ie, breathable, while still preventing the exudates from passing through the backsheet 30). The topsheet 28 is docile, of soft feel and non-irritating to the wearer's skin. In addition, the topsheet 28 is permeable to liquids allowing liquids (eg, menses and / or urine) to easily penetrate through its thickness. A suitable top sheet 28 can be manufactured from a wide range of materials such as woven and nonwoven materials; polymeric materials such as thermoplastic films formed with openings, plastic films with openings, and hydroformed thermoplastic films; porous foams; cross-linked foams; crosslinked thermoplastic films; and thermoplastic canvases. Suitable woven and nonwoven materials may be composed of natural fibers (for example, wood or cotton fibers), synthetic fibers (for example, polymer fibers such as polyester, polypropylene or polyethylene fibers), or from a combination of natural and synthetic fibers. There are a number of manufacturing techniques that can be used to manufacture top sheet 28. For example, top sheet 28 can be a non-woven web of fibers. When the top sheet comprises a nonwoven web, the web can be spun bonded, carded, wet laid, blown in the molten state, hydroentangling combinations of the above and the like. A preferred top sheet is carded and thermally bonded by means well known to those skilled in the art of fabrics. A preferred top sheet comprises polypropylene fibers of cut length having a denier of about 2.2. As used herein, the term "fibers of cut length" refers to those fibers that have a length of at least about 15.9 mm. Preferably, the top sheet has a basis weight from about 18 to about 25 grams per square meter. A suitable topsheet is manufactured by Veratec, Inc., a division of International Paper Company, of Walpole, Massachusetts under the designation P-8. In a preferred embodiment of the present invention, the body surface of the formed top sheet of film is hydrophilic to help transfer the liquid through the top sheet faster than if the body surface were not hydrophilic, to decrease the likelihood of the menstrual fluid flowing out of the upper sheet instead of flowing into and being absorbed by the absorbent core. In a preferred embodiment, surfactant is incorporated into the polymeric materials in the formed film topsheet as described in U.S. Patent Application No. 07 / 794,745"Absorbent article having a film cover with openings and non-woven material ", presented on November 19, 1991 by Aziz et al., which is incorporated herein by reference. Alternatively, the body surface of the topsheet can be made hydrophilic by treating it with a surfactant such as described in the aforementioned U.S. Patent No. 4,950,254 issued to Osborn and incorporated herein by reference. For purposes of the present invention, a sanitary napkin here will generally have a caliper in its central region 52 of less than or equal to about 7 mm, preferably less than or equal to 5 mm, more preferably less than or equal to about 4 mm, and most preferably less than or equal to about 3 mm. The above calibers are to be measured with a comparator meter that has a test weight of 80.0 grams. The comparator meter must have a comparator seat that weighs 10 grams and has a diameter of 2.44 cm. The comparator meter should have a contact surface area of 4.67 square cm.

The sanitary napkins of the present invention may also be provided with any of the optional additional components that are known in the art. The optional components may include one or more absorbent or fluid transport layers, secondary topsheets, optional inner liners, fastening means and a removable cover strip or release liner. The sanitary napkin may also be provided with fins or "wings" as shown in Figure 4 that are folded around the crotch portion of the wearer's undergarment. Examples of this sanitary napkin are more fully described in U.S. Patent No. 4,589,876 issued to Van Tilburg on May 20, 1986, and in U.S. Patent No. 4,687,478 issued to Van Tilburg on August 18, 1987, each of which are incorporated herein by reference. In a preferred embodiment, the garment facing surface of the backsheet 30 may include means for securing the sanitary napkin 20 to the wearer's undergarment, hereinafter referred to as the pad anchoring means (not shown in FIG. Figure 1). The pad attachment means may include mechanical fasteners or, preferably, adhesive fasteners such as a pressure sensitive adhesive. A removable release liner preferably covers the adhesive fastening means in order to prevent the adhesive from drying or sticking to a surface before the sanitary napkin is used. The adhesive can be applied to the garment facing surface of the backsheet, in one, two or several parallel strips or for example two outwardly oriented, convex, significantly opposite strips. The adhesive strips may be between about 5 to about 35 mm, preferably between 15 mm and 26 mm wide. Preferably, the strips of the adhesive are sized and arranged in such a way that the distance between the inner edges of the strips is approximately 28 mm, and the distance between the outer edges of the strips is approximately 60 mm. Alternatively, the adhesive may be applied to the backsheet in a generally centered rectangular patch that covers from about 30% to about 70% of the area of the garment facing surface of the backsheet. The appropriate adhesive can be that specified as "0.6 mil pass" available from Century Adhesive as NO. of Product 8305-4 or from Anchor Continental, 3 Sigma Division of Covington, Ohio. The sanitary napkin 20 of the present invention has divergent flexural strength; for example, the resistance to bending to the end regions 50, and 54 is maintained to be generally greater than that of the central region 52. In this way, the sanitary napkin 20 of the present invention is more flexible in its region. central 52 and less flexible in its end regions 50 and 54. Preferably, the end regions 50 and 54 of the sanitary napkin 20 of the present invention have flexural strengths that are at least 25% greater and preferably 50% higher that in the central region 52. In addition, the flexural strength in the central region 52 will preferably be less than or equal to about 600 grams while the flexural strength in the end regions 50 and 54 will preferably be less than or equal to to 1000 grams. At least one stabilizing member 42 is disposed in each end region 50 and 54, respectively, each stabilizing member 42 is preferably positioned adjacent each end edge 40 of the sanitary napkin 20, to increase the flexural strength (i.e. , stiffness), and the end regions 50, 54 and the end edges 40, beyond that of the central absorbent region 52 to allow the sanitary napkin to configure itself in a way that provides improved fit and allows the best absorbent efficiency of the absorbent core 32. More importantly, the hardened end regions, 50, 54, including the end edges 40) decrease the tendency for a sanitary napkin 20 to overturn or at least partially reduce excessive coiling during use. Note, when the sanitary napkin 20 herein is in use, the compression of the thighs along the longitudinal edges 38 is resisted by the hardened end regions 50 and 54. Also during the course of use by a user, ( that is, during sitting, standing, walking, running, climbing, etc.), it is believed that the sanitary napkin 20 will have less tendency to wind up on account of the stabilizing members 42 placed in the end regions 50, 54, of the towel especially on its end edges. In general, the force required to affect uniform lateral compression throughout the sanitary napkin 20 is greater in the first and in the second end regions50, 54 (and especially the end edges 40 therein), which in the central region 52. This is by virtue of the stabilizing members 42 located in the end regions 50 and 54. This effect may cause some additional compliance to the body of the sanitary towel 20 for a user when the user presses his thighs against the lateral edges 38 of the towel. By the term "lateral compression" is meant here that force required to compress a portion of the sanitary napkin 20 along the transverse axis 100. By the term "end regions", it is meant herein regions extending from and which may include end edges 40 that are between about 1/10 and 1/3 the length of the sanitary napkin to the transverse center line. The stabilizing members 42 may be disposed anywhere through the thickness of the sanitary napkin 20, including on the surface 29 of the topsheet 28, between the absorbent core 32 and the topsheet 28, between the absorbent core 32 and the sheet 30, or on the garment surface 31 (not shown) of the backsheet 30. As shown in Figures 1 and 2, the stabilizing members 42 are generally disposed between the topsheet 28 and the backsheet 30. Alternately, a stabilizer member 42 can at least lie on at least a portion of the absorbent core 32 to distribute the fluid directly back toward the core 32. Stabilizing member 42 can be placed in place between the layers of the towel by adhesives, thermal bonding, compression bonding, ultrasonic bonding and the like. Any of the suitable joining techniques, for example, thermal bonding to combine the layers of the towel, for example, joining a core to a top sheet, can be employed herein for the attachment of the stabilizing member 42 to any of the elements of the sanitary napkin. As used herein, the term "attached" includes configurations by which the stabilizing members are fixed directly to portions of the sanitary napkin and configurations by which a stabilizing member is indirectly attached to an intermediate member or intermediate members which turn to the sanitary towel. The stabilizing members 42 may also be part of, i.e., attached to, the absorbent core 32. The stabilizing members 42 may be attached below or directly on top sheet 28 at a number of different locations, zones and patterns. For example, a stabilizing member 42 can be attached below or on top sheet 28 at a point, (a point of attachment), inward of an end edge 40, so that stabilizing member 42 can be separated away from the user surface of the top sheet during use to form a vertical barrier for the longitudinal flow of body exudates. Figures 3A to 3D show that the stabilizing members 42 can have any of a number of configurations that can provide the necessary stiffness as described herein. The shapes of surface area, i.e. the shape as viewed directly from the top of the stabilizing member can be rectangular, trapezoidal, elliptical or any other shape. In general, the shape of the stabilizing member will depend on considerations of performance and discretion of the sanitary napkin for the wearer, as well as considerations of manufacturing capacity and packing compatibility of the sanitary towel manufacturer. In accordance with the present invention, the shape of the stabilizing member can be of any shape, such as a type of rectangular, oval, round shape or of an asymmetric or non-asymmetric type. Particularly preferred shapes are half-moon, oval, circular, semicircular, or rectangular, which may be rounded on all or some of the edges. The stabilizing attachment means 44 (Figures 2A and 2B) may be any joining means known in the art for securing several elements together in a sanitary napkin, such as the stabilizing members 42 fixed to a sanitary napkin 20 in the end regions 50 and 54. For example, the stabilizing attachment means 44 may comprise adhesives, heat / pressure seals using known heat / pressure sealing techniques in the art, ultrasonic bonds using ultrasonic bonding techniques known in the art, dynamic mechanical bonds using mechanical dynamic bonding techniques known in the art, or any other materials or methods for absorbent articles known in the art. The stabilizing fixing means 44 is preferably an adhesive such as a layer of adhesive 44 as shown in Figures 2A-2B. As seen in Figure 2B, the stabilizing member 42 is attached to the backsheet 30 directly by a fixing means 44. In this case, the stabilizing means 42 are not and therefore do not need to be attached or fixed to the absorbent core. 32. Also, the stabilizing member 42 can be fixed separately to the upper sheet 28 by a fixing means 44 or fixed to both of the upper sheet 28 and the rear sheet 30 by a separate fixing means 44. In Figure 2, the stabilizing member 42 can be additionally or separately attached to the topsheet 28 through a fixing means 44. This additional fixation would occur where the stabilizing member 42 is also fixed to the absorbent core 32 by a fixing means. 44. The material of the stabilizing member can be a simple homogeneous material, a mixture of different homogeneous materials, or a combination of different non-homogeneous materials (for example, a layered construction). The materials of the stabilizing member can be made from the same materials as the absorbent core materials, the top sheet materials, or the backsheet materials as discussed above. The material of the stabilizing member may be a floor material, which is soft and thick, preferably elastic, such as the hydrophobic nonwoven fabric, bound through air with a basis weight of 60 grams, as supplied by The Veratec Company of Walpole, MA. The material of the stabilizing member can also, for example, be selected to have an absorbent capacity or it can be without absorbent capacity. If the stabilizing member has an absorbent capacity, the material chosen for the stabilizing member preferably maintains a stiffness when wet which reduces excessive winding in the end regions 50, 54 when these regions are impacted by the fluid. Suitable materials include high-floor or bulking polyesters, rayon, orlon, other polyolefin materials, and mixtures thereof. In a preferred embodiment, the stabilizing member is constructed from an absorbent that maintains the stiffness greater than the unreinforced areas. The stabilizing member is preferably wrapped in a web of nonwoven material or film material formed as described herein for the materials of the topsheet. In one embodiment, a sanitary napkin may have a stabilizing member in the form of an additional absorbent material placed in the end regions / edges. The additional absorbent material may comprise any of the materials specified herein as being suitable for use in the absorbent core. From the use of these materials, the end regions / edges can be used not only to provide a stabilizing function to the end regions / edges, but also to provide some absorption of the fluid dispersed in a longitudinal direction towards the regions / shores. The additional absorbent material may also comprise capillary channel fibers (described in more detail below), or cross-linked cellulose fibers. Reticulated cellulose fibers are described in U.S. Pat. No. 4,88,093 issued December 19, 1989 to Cook et al .; U.S. Patent No. 4,822,543 issued April 18, 1989 to Dean, et al .; U.S. Patent No. 4,889,559 issued December 26, 1989 to Schoggen et al .; U.S. Patent No. 4,898,642 issued February 6, 1990 to Moore et al., and U.S. Patent No. 4,936,022 issued June 19, 1990 to Lash and others. The additional absorbent material may be in any suitable form, including but not limited to masses or wadding of material, single sheets unfolded, folded sheets, strips of material, loose or bonded fiber, multiple layers or laminates of material, foam layers including polyester and foams developed from high internal phase emulsions (HIPE) or other combinations of these materials. The additional absorbent material can be placed between any of the components between the top sheet and the back sheet. The material for a stabilizing member (i.e., hereinafter referred to as "stabilizing material"), may, for example, comprise polymeric gelling agents added or in a pattern within the end regions and / or along the end edges. In other alternatives, the stabilization material may include, but is not limited to, combinations of polymeric gelling agents and synthetic fibers, natural fibers, chemically modified natural fibers, such as cross-linked cellulose fibers. In still other embodiments, suitable absorbent fibers such as chemically modified natural fibers can be used as the stabilizing material without the addition of the polymeric gelling agents. A preferred type of stabilization material is a two-component fibrous material comprising two-component fibers having a polyethylene core, which are coated with a polypropylene coating. The exterior of the two-component fibers have an internal melting temperature than the interior.

This material is preferred because the fibers can be bonded with heat to one another, melting the outside of the fibers, while the inside of the fibers maintains its fibrous integrity instead of melting into an amorphous mass. Suitable two-component fibers are commercially available from a company by the name of Chisso. Another matter! which is suitable for use as the stabilization material is a fibrous material known as PULPEZ, formerly available from Hercules, Incontinence., from Wilmington, Delaware. As mentioned hereinabove, another preferred type of stabilizing element for the present invention are those foams developed from - high internal phase emulsions (HIPE) known in the art as functional absorbent materials or FAM foams. The functional absorbent materials are discussed extensively in U.S. Patent No. 5,387,207, issued to Dyer et al., And in U.S. Patent No. 5,563,179, issued to DesMarais, and others, each of which are incorporated herein by reference. The sanitary napkin can be provided with an optional inner liner. The optional inner liner is used when the sanitary napkin is provided with an absorbent core that has the ability to separate or "unbent" from the backsheet for improved body contact. The concept of decoupling and the characteristics of the inner liner are described in U.S. Patent No. 5,007,906 issued to Osborn and others on April 16, 1991, which is incorporated herein by reference.

For each of the embodiments herein, the stabilizing members 42 may be any of the following groups: non-absorbent and permeable material; non-absorbent and waterproof material; non-absorbent and inherently waterproof but perforated material, grooved or similar, to make the member permeable or absorbent. The non-absorbent stabilizing members 42 may comprise any suitable non-absorbent material. For example, a non-absorbent stabilizing member 42 may comprise a foam insert, for example, a functional absorbent material as described in U.S. Patent No. 4,387,207, issued to Dyer et al. And which is hereby incorporated by reference. reference, or a rigid strip of rigid plastic film. In a preferred embodiment of the present invention, Figure 4 shows the sanitary napkin having two fins 64, each of which are adjacent to and extend laterally from the lateral edges of the absorbent core. The fins 64 are configured to fold over the edges of the wearer's panties in the crotch region, such that the fins 64 are disposed between the edges of the panties-and the thighs of the wearer. The fins 64 serve at least two purposes. First the fins help to avoid the staining of the body and the wearer's panties by the menstrual fluid, preferably forming a double-walled barrier along the edges of the panty. Second, the fins 64 are preferably provided with fastening means on their garment surface, such that the fins 64 can be folded back under the pantyhose and attached to the garment-facing side of the panty or a flap 64. to the other. In this way, the fins 64 serve to keep the sanitary napkin 20 properly positioned in the pantyhose. The fins 64 may be constructed of various materials, including materials similar to the topsheet 28, the backsheet 30, tissue, or combinations of these materials.

In addition, the fins 64 can be a separate element attached to the main body of the towel 20, or they can comprise extensions of the topsheet 28 and the backsheet 30 (ie, a unitary construction). A number of sanitary napkins having suitable or adaptable fins for use with the sanitary napkins of the present invention are disclosed in U.S. Patent No. 4,687,478 entitled "Towel-Shaped Sanitary Towel", which was issued to Van Tilburg, August 18, 1987; U.S. Patent No. 4,589,876 entitled "Sanitary Towel", which was issued to Van Tilburg on May 20, 1986; and in U.S. Patent No. 4,608,047 entitled "Sanitary Towel Fixation Means", which was issued to Mattingly on August 26, 1986. Each of these patents is incorporated herein by reference. Although a preferred embodiment of the present invention has been described, numerous other embodiments of the sanitary napkin are disclosed in the literature. These may be provided with stabilized end regions / edges of the present invention. Several of these sanitary napkins are disclosed in U.S. Patent No. 4,950,264 issued to Osborn on August 21, 1990, U.S. Patent No. 5,007,906 entitled "Sanitary Towel Uncoupled", issued to Osborn and others on October 16, 1990. April 1991 U.S. Patent No. 5,009,653, issued to Osborn on April 23, 1991; U.S. Patent No. 4,917,697 issued to Osborn et al. on April 17, 1990, and the aforementioned publication of European Patent Application Nos. 0 335 252 and 0 335 253 published in the name of Buell on October 4, 1989, and the publication of the European patent application No. 0 471 114 A2 on February 19, 1992, and in U.S. Patent Application Serial No. 07 / 605,583 entitled "Sanitary towel having components capable of separating during use", filed in the name of Visscher et al. On October 29. of 1990; U.S. Patent Application Serial No. 07 / 630,451 entitled "Sanitary towel having a transversely segmented core", filed in the name of Osborn et al. on December 19, 1990; U.S. Patent Application No. 07 / 707,233 entitled "Sanitary towel having laterally extensible means for affixing to the wearer's undergarment", filed May 21, 1991 in the name of Osborn et al. The sanitary napkin of the present invention can, for example, be provided with a flexure-resistant deformation element similar to those described in the publications of European patent applications Nos. 0 335 252 and 0 335 253. The flexure-resistant deformation element can be used to assist the sanitary napkin to assume certain configurations when used. For example, this element can be used to make regions of the sanitary nap predispose to fold up or down when the towel is used. In an alternate embodiment, of the sanitary napkin 20 of the present invention, the absorbent core 32 of the sanitary napkin 20 may comprise a three layer structure comprising: an acquisition layer; a layer of tissue; and a storage layer. The acquisition layer is placed adjacent to the topsheet 28 to quickly acquire and distribute menstruations or other body fluids (examples of suitable acquisition layers are described in U.S. Patent No. 5,137,537 issued to Heran &Cooper. on August 11, 1992; U.S. Patent No. 5,009,653, issued to Osborn on April 23, 1991, or in the international publication WO 93/11725, The Procter &Gamble Company, published on June 24, 1991; 1993, each of which is incorporated herein by reference.The tissue layer is placed between the acquisition layer and the storage layer in order to better distribute menstruations towards the storage layer from the acquisition layer, (the The tissue is preferably a layer of cellulose tissue, as marketed by The Procter & amp;; Gamble Company under the trademark PUFFS or any other tissue as known in the art). The storage layer is designed to retain menses or other body fluids. Therefore, the storage layer is placed adjacent to the backsheet 30, between the backsheet 30 and the tissue layer (the storage layer can be any of the absorbent layers as described herein with respect to the absorbent core. , but is preferably a superabsorbent laminate such as described in the aforementioned US Patents No. 4,950,264 and 5,009,653 each issued to Osborn). The stabilizing members 42 do not need to be flat, but may have a three-dimensional structure such as to make them better fit within the perineum or vitreous groove, allowing discharged exudates to be better retained within the sanitary towel 20. Liquid exudates which are deposited on the core 32 will tend to be redistributed radially outwards from the place where they are deposited. The flexural strength of the end region and the central regions of the sanitary napkin of the present one is measured by the maximum stiffness to bending. The maximum stiffness to bending is determined by a test that is modeled or molded after the CIRCULAR DOUBLE PROCEDURE ASTM 4032.82 the procedure being considerably modified and performed as follows.

The circular bending procedure is a simultaneous multiple directional deformation of a material in which one face of a specimen becomes concave and the other face becomes convex. The CIRCULAR DOUBLE PROCEDURE gives a force value related to the flexural strength, simultaneously averaging the rigidity in all directions. The CIRCULAR DOUBLE PROCEDURE for the embodiments herein has been appropriately altered to correctly measure the flexural strength in the end / end edge regions of the sanitary napkin 20 herein. However, the entire process is disclosed in U.S. Patent No. 5,009,653, the patent of which is hereby incorporated by reference.

APPARATUS The apparatus required for the CIRCULAR DOUBLE PROCEDURE is a modified circular bending stiffness tester, which has the following parts: a uniformly polished steel plate platform that is 102.0 x 102.0 x 6.35 millimeters, having an orifice 18.75 millimeters in diameter. The overlap edge of the hole should be at an angle of 45 degrees to a depth of 4.75 mm. A plunger having a length of 72.2 mm, a diameter of 6.25 mm, a spherical tip having a radius of 2.97 mm and a needle tip extending 0.88 mm therefrom having a base diameter of 0.33 mm and a point that has a radius less than 0.5 m, the piston being mounted concentric with the hole and having a clear equal on all sides. Note that the needle point is only to prevent lateral movement of the test specimen during the test. Therefore, if the needle point significantly adversely affects the test specimen (it stings an inflatable structure), the needle point should not be used. The lower part of the plunger must be fixed well above the top of the orifice plate. From this position, the downward stroke of the spherical tip will be exact below the plate hole. A force meter and more specifically an Instron inverted compression load cell should be used. The load cell has a loading range of from about 0.0 to about 2000.0 grams. An actuator must be used to activate the load cell and more specifically the Instron Model No. 1122 which has an inverted compression load cell. The Instron 1122 is made by Instron Engineering Corporation, Canton, Mass.

NUMBER AND PREPARATION OF SPECIMENS In order to perform the procedure for this test as explained below, five representative sanitary napkins are required. From one of the five towels that have any adhesive release paper from the removed pantyhose and the blocked adhesive, which is to be tested, some numbered "X" and "Y", each of the test specimens of 37.5 x 37.5 mm. The specimen "X" is taken from the end regions and will specifically include at least a portion of a stabilizing member 42. The specimen "Y" is taken from the central region 52 and does not comprise any part of the stabilizing member 42 , without however some parts of all of the other components of the towel within the central region 52. Specimens having portions in which a top sheet is directly attached to a barrier sheet must not be tested. The reason why these specimens are not tested, is due to the verification that the existing prior art towels, in which a top sheet is attached to a barrier sheet beyond the edge of an absorbent core , on the periphery of the towel these parts of which are highly flexible. Therefore, a number of different specimens should be tested from each sanitary pad. Test specimens should not be bent or flexed by the person performing the test, and the manipulation of the specimens should be kept to a minimum and for the edges avoid to affect the properties of the resistance to flexion. Of the remaining four sanitary napkins, an equal number of "X" and "Y" of specimens of 37.5 x 37.5 mm, identical to the cut specimens of the first towel, is cut. Therefore, the person performing the test must have a number of "X" and "Y" games of five identical specimens. The procedure for the CIRCULAR DOUBLE PROCEDURE is as follows. The specimens are conditioned by leaving them in a room which is at 21 + 1 ° C and 50 + -2% relative humidity during a period of two hours. The test plate is level. The piston speed is set at 50.0 cm per minute for the total length of the stroke. A specimen is centered over the hole under the plunger in such a way that the body surface 26 of the specimen is facing the plunger and the garment surface 17 of the specimen is facing the platform. Of course, any adhesive release paper is removed from the pantyhose (if present), to simulate the conditions of use. Any panty adhesive (if present), must be blocked using means well known to those skilled in the art, such as glycerin and / or talcum, to prevent the specimen from adhering to the platform and obtaining maximum rigidity at the artificially elevated bending. If desired, the specimen can be centered over the hole on the body surface 26 facing the platform and the garment surface 12 facing the plunger to obviate the need for any adhesive that may be present. The zero indicator is checked and adjusted, if necessary. The plunger is activated. Avoid touching the specimen during the test. The reading of the maximum force to the nearest gram is recorded. The above steps are repeated until all five of the identical specimens have been tested.

CALCULATIONS The maximum flexural stiffness for each specimen is the reading of the - maximum force for that specimen. Remember that the number "X" and "Y" of the games of the five identical specimens were cut. Each set of five identical specimens is tested and the five values received for that set are averaged. In this way, the person testing now has an average value for each of the "X" and "Y" games tested. The sanitary napkin of the present invention has a liquid capacity large enough to absorb menstrual flows from medium to high. Two capacities are determinable, which, depending on the size of the sanitary pad, can be the same: Test capacity and Total capacity. Preferably, the sanitary napkin 20 of the present invention has a test capacity of at least 8.0 grams, more preferably at least about 15.0 grams, and most preferably at least 18.0 grams. Preferably, the sanitary napkin 20 of the present invention has a total capacity of at least 20.0 grams, more preferably of at least about 30.0 grams and most preferably of at least 40.0 grams.

CAPACITY PREUBA The test and total capacities of a sanitary napkin are determined as follows: remove any adhesive release paper from the panty towel of the towel to be tested. To determine the test capacity, a sample is obtained from a part of 4.75 by 14.0 cm, or any other configuration that has 66.5 cm square, of the sanitary napkin. The sample is cut from the portion of the sanitary napkin that would be centered under the vaginal orifice when the sanitary napkin is used. The total capacity is determined using a sample comprising the total towel minus any release paper. The sample is weighed to the nearest 0.1 gram. The sample is then immersed in a beaker of sterile saline (obtained from Baxter Travenoi Company of Deerfield, Illinois), such that the sample is totally submerged and is not flexed or bent or otherwise bent. The sample is submerged for 10 minutes. The sample is removed from the saline solution and suspended for two minutes in a vertical position to allow the saline solution to drain from the sample. The surface facing the body of the sample is then placed down on an absorbent filter paper. Such as paper # 631 available from Filtration Science Corp., Eaton-Dikeman Division of Mount Holly Springs, Pennsylvania. A uniform load of 17.6 grams per square centimeter is placed on the sample to release the excess fluid. The absorbent filter paper is replaced every 30 seconds until the amount of fluid transferred to the absorbent filter paper is less than 0.5 grams in a period of 30 seconds. Next, the sample is weighed to the nearest 0.1 gram and the dry weight of the sample is subtracted. The difference in grams is the test capacity or total sample, whichever may be the case. The sanitary napkin 20 should be reduced according to the crotch width scale of the wearer's undergarment. A sanitary napkin 20 having a width of the central absorbent, which corresponds to the absorbent with the crotch edges of the undergarment, is particularly preferred. For the relatively narrow crotch of the undergarment, which have a width of about 3.7 to about 6.4 cm, a sanitary napkin having a width of! central absorbent 63 of about 3.7, 6.4 cm works well. The term "width of the central absorbent", and a method of measuring same, are described in U.S. Patent No. 5,009,653. The sanitary napkins 20 of the present invention are relatively thin. This is preferred to keep the sanitary napkins 20 of the present invention relatively thin, such that the sanitary napkins 20 of the present invention will be discrete and the wearer will have a lower or lower knowledge of the sanitary napkin while it is being used. The sanitary napkin 20 shown in Figure 1 can have a caliber of approximately 1.9 mm. The size of a sanitary napkin 20, or several of its regions, is determined by the following test. A comparator meter and specifically the Ames, Model 130 with a disc indicator Model 482, available from B.C. Ames, Company of Waltham, Massachusetts is needed. The comparator meter should have a circular comparison seat made of aluminum and that has a weight of 10 grams and a contact surface of 5.16 square cm. The comparison meter is set to 0. A stainless steel weight of 80.0 grams is placed on the axis that extends above the comparison disk. The comparison seat is raised and the sanitary towel, with any release paper of the panty adhesive being removed and the adhesive is sprinkled with corn starch and the garment surface of the towel is placed down on the base plate . The towel is placed on the base plate in such a way that when the seat is lowered it is in the region of the towel for which the measurement is desired. Test de-wrinkling or avoiding any of the wrinkles on the towel. Gently lower the base on the towel. Determine the caliber of the towel by reading the dial of the comparator 30 seconds after the base comes in contact with the towel. Although particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications may be made without departing from the spirit and scope of the invention. Therefore, attempts are made to protect all these changes and modifications within the scope of the invention in the appended claims.

Claims (6)

1. - A sanitary napkin having a longitudinal center line, a transverse center line, a pair of longitudinal edges, two end edges, a first end region extending from one end edge, to the transverse center line, and a second end region extending from the other end edge towards the transverse center line, and a central region positioned between the first and second end regions, a sanitary napkin comprising a first surface and a second surface opposite the first surface , characterized in that: said central region has a transverse width greater than or equal to about 5 cm, and the flexural strength of the sanitary napkin as measured through at least one end region is greater than the resistance to the flexing of the sanitary napkin as measured across the central region, the sanitary napkin having a caliber less than about 5 m m as measured through the first and the second end regions, said first and second end regions each preferably comprising at least one stabilizing member, each stabilizing member preferably being positioned adjacent to the first and second edges of extreme.

2. A sanitary napkin having a longitudinal center line, a transverse center line, two longitudinal edges, two end edges, a first end region extending from one end edge to the transverse center line. A second end region extending from the other end edge to the transverse center line, and a central region positioned between the first and second end regions, the sanitary napkin comprising a liquid-permeable top sheet, a back sheet impervious to liquid. liquid attached to the upper sheet, and an absorbent core placed between the upper sheet and the back sheet, said absorbent core having two longitudinal edges and a width defined by the longitudinal edges, characterized in that: said central region has a greater transverse width than or equal to about 5 cm, and the flexural strength of the sanitary napkin as measured through at least one end region is greater than the flexural strength of the sanitary napkin as measured by the central region, and said sanitary napkin having a caliper of less than about 5 mm as measured by the first and the s second end regions, said first and second end regions each preferably comprising at least one stabilizing member, each stabilizing member, preferably being positioned adjacent said first and said second end edges.

3. The sanitary napkin according to claim 1 or 2, having a caliper as measured by said first and said second end regions not greater than about 3 mm.

4. The sanitary napkin according to claim 1 or 2, wherein said first and said second end regions extend from the end edges of the sanitary napkin from about 1/10 to about 1/3 of the length of the sanitary towel towards the transverse center line.

5. The sanitary napkin according to claim 1 or 2, wherein the resistance to bending of said first and said second end regions is at least about 25 greater than said resistance to flexion of the central region, and preferably at least about 50% greater than the flexural strength of said central region.

6. The sanitary napkin according to claim 1 or 2, wherein the flexural strength of said central region is not greater than about 600 grams, and preferably not greater than about 100 grams.