MXPA02008155A

MXPA02008155A - Absorbent articles exhibiting improved buckling and bending softness.

Info

Publication number: MXPA02008155A
Application number: MXPA02008155A
Authority: MX
Inventors: Gary Dean Lavon
Original assignee: Procter & Gamble
Priority date: 2000-03-10
Filing date: 2000-03-10
Publication date: 2002-11-29
Also published as: KR20020077531A; BR0017152A; WO2001068022A1; EP1267769A1; CN1450884A; AU2000236228A1; JP2003526464A; CA2399797A1

Abstract

An absorbent article, in particular a diaper, having a composite comprising a topsheet, a backsheet, and an absorbent structure in between, which upon application of a deformation force first buckles with a certain buckling resistance corresponding to a buckling force, whereby upon further deformation the buckling deformation mechanism changes to a bending deformation mechanism with a corresponding lower deformation force.

Description

FLEXION FIELD OF THE INVENTION The present invention relates to absorbent articles, such as * baby diapers, underpants for infants, incontinence articles for adults, feminine protection articles and the like. In particular, the present invention relates to such articles that are comfortable for the user to be designed to exhibit a particular softness, even more so that such articles exhibit a high liquid handling capacity.

BACKGROUND OF THE INVENTION Infants and other incontinent individuals use absorbent articles such as diapers to absorb and hold urine and other body exudates. The absorbent articles function both to contain the discharged materials and to isolate these materials from the wearer's body and from the wearer's garments and bedding. Disposable absorbent articles having many different basic designs are known in the art. For example, U.S. Patent No. Re. 26,152, entitled "Disposable diaper", issued to Duncan and Baker, January 31, 1967, describes a disposable diaper which has achieved wide acceptance and commercial success. U.S. Patent No. 3,860,003, entitled "Shrinkable side portions for disposable diaper", issued to Buell on January 14, 1975, describes a disposable diaper with an elastic leg cuff which has achieved wide acceptance and commercial success.

Memas the containment and isolation requirement, it has been widely recognized, that comfort for the user is an important aspect for the design of such articles. Even though many methods are known for items such as pantyhose or catamenial pads, as disclosed in U.S. Patent No. 4,950,264 (Osborne et al.), Designs for articles that require superior liquid handling performance such as baby diapers or incontinent adults have typically been relatively broad and bulky, when dry and particularly when wet, in the region of the article that fits between the wearer's legs. An attempt to improve user comfort in these cases has been described in U.S. Patent No. 4,610,678 (Weisman et al.). In U.S. Patent No. 5,098,423 to Pieniak et al., A disposable diaper of low volume in the dry state is described, focusing on a relatively low cross-sectional area, when dry, particularly in the "discharge zone" ( which is defined in the patent as the second and third fifth of the length of the article, i.e., generally in the crotch region of the user). The main method is to distribute the absorbent material in this discharge area over a wider area, which during use can be piled up when being pressed between the user's legs. Still another technique focuses on providing absorbent articles of high performance, with a narrow crotch, low thickness and high liquid handling performance, see for example PCT publication WO 98/43580. The strict liquid handling performance requirements for such materials, or composites comprise relatively soft materials, which in turn lose much smoothness when combined to form laminated materials or laminate-like structures. However, such elements frequently exhibit significant stiffness increased * * as is well known from, for example, structures called "sandwich" that are used as reinforcement elements or cardboard corrugation. Thus, even when several attempts have been made to improve the softness of absorbent articles of high liquid handling performance, there is still a need to improve user comfort without compromising the operation of exudate handling of the article.

BRIEF DESCRIPTION OF THE INVENTION The present invention is a disposable absorbent article having a crotch region to be placed between the user's legs during their intended use, and at least one end region, comprising a composite material made of a top sheet, a sheet later joined to the upper sheet, and an absorbent structure between them, extending at least to parts of the regions 15 crotch and end mentioned above. In particular, this composite material exhibits a forceful relationship of volumetric softness for the crotch and end regions. { BS} versus displacement. { s} for a displacement, which can be expressed as a mathematical curve, for which a derivative (d (BS) / ds) = (BS ') can be determined (which for these composites has at least one of the 20 regions a displacement value (s0) for which the derivative of the curve has a value of zero. Then, for this displacement value (s0) the composite exhibits a force value of volumetric smoothness (BS { S0.}.) Less than 10 N, preferably less than 7.5 N and even more preferably less than 5 N. Preferably, the volumetric softness in the crotch region is 25 lower than that of an end region, and is preferably less than 5 N, or more preferably less than 3 N.

In the preferred embodiments of the absorbent structure, this includes a capillary absorption layer, which has a value of volumetric softness of less than 3 N, preferably less than 1 N.

The capillary absorption can be a fibrous fabric, which is treated by an activation treatment subsequent to its formation, preferably by means of a double-pass treatment. The absorbent structure may also have an acquisition layer having a volumetric softness value of less than 3 N, preferably less than 1 N. The absorbent structure may additionally comprise a layered absorbent composite, such as with a support layer, and particles which are capable of absorbing liquids, such as superabsorbent gelling polymers, polymeric foam materials, and combinations thereof, which can be attached to the aforementioned support layer. This layered absorbent composite can be discontinuous, having two regions, which are spaced apart from each other longitudinally, preferably such that at least one of these regions extends within an end region, preferably the back region, of the aforementioned article. . The backing layer for the layered absorbent composite may comprise woven or spongy nonwoven structures, to which the particles can be bonded by a joining means, such as hot melt blown melt adhesive. The layered absorbent composite immobilizes the particles, preferably the particles are immobilized at a magnitude of at least about 80% based on the dry weight, preferably at least about 95%. The basis weight of the particle may be greater than about 100 g / m2, preferably greater than about 300 g / m2, more preferably greater than about 500 g / m2. The absorbent structure can be designing f to provide an absorbent capacity, so that the aforementioned spacing region has a final absorbent capacity, which is less than about 55% of the final absorbent capacity of the aforementioned absorbent structure. The absorbent structure can also be designed to provide a final absorbent capacity of the aforementioned absorbent structure, which is positioned towards the rear of the crotch point is greater than about 60% of the final storage capacity of the article. In a particular aspect of the present invention, an absorbent article with an absorbent structure, having an anterior and posterior end edge of the waist having an edge width of the anterior and posterior end of the waist; may have two central regions aligned on each side of the longitudinal center line of the article, and two adjacent lateral regions laterally disposed outwardly from the respective aforementioned central regions of the aforementioned absorbent structure, each of the adjacent side regions extending into a width of up to 25% of the widest portion of the absorbent structure, outward from the central regions. This additional absorbent structure has at least two layers of absorbent material which are in a contact relationship, thereby defining a common contact surface area, by means of which these two layers are joined to one another by means of a joining means, such as a hot melt adhesive, which covers an area of the bonding medium, which is less than the common contact surface area, so that at least 75% of the area of the bonding means is located within the core region .

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 - Absorbing article. ? áÁÁÁLÁÁ L? t? M? - ** ^ Ffgra 2 - Schematic description of the definition of the spawn point. Figure 3 to 5 - Absorbent cores useful for the present invention. Figure 6 - Fastener drawings / volumetric softness method. Figure 7 - Typical curve resulting from the volumetric softness test.

DETAILED DESCRIPTION OF THE INVENTION General Definitions As used in the present invention, the term "absorbent article" refers to devices that absorb and contain body exudates, and, more specifically, refers to devices that absorb and contain body exudates, and, more specifically, reference to devices that are placed against or close to the body of the user to absorb and contain the different exudates discharged from the body. Absorbent items that include devices designed to absorb urine are used by incontinent people. Such incontinence articles include but are not limited to articles designed to receive large quantities of liquids at relatively high discharge rates, such as diapers, adult incontinence briefs, training underpants, supports and diaper liners. The term "disposable" is used in the present invention 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 discarded in a manner compatible with the environment). A "unitary" absorbent article refers to an absorbent article that is formed of separate parts joined together to form a coordinated entity of so that they require separately manipulated parts such as a separate support or liner. As used in the present invention, the term "absorbent core" refers to the portions (e.g., layers) of an absorbent article whose function is to acquire, distribute, transfer, transport and / or redistribute liquid. Acquisition materials include materials whose main function is to acquire and then deliver liquids. Such materials include acquisition layers, backsheet materials, transfer layers, flow control modules, tissue wrapping papers or non-woven sheets designed to prevent the migration of hydrogel-forming polymers, etc. As used in the present invention, the term "distribution material" refers to the material (s) of the absorbent core whose primary function is to absorb and distribute / redistribute liquids to points away from the initial point of liquid loading. As used in the present invention, the term "storage material" refers to the absorbent core material that has the majority of the liquid absorbed by the article. It should be understood that the terms "distribution material" and "storage material" are not mutually exclusive. In certain embodiments, an individual material may function to provide both liquid distribution and liquid storage. As used in the present invention, the term "above" refers to the portion of an absorbent article or core that is intended to be placed close to the front of the user. The term "after" refers to the portion of an article or absorbent core that is intended to be placed close to the back of the user. Thus, the use of the relative term "in front of" means a position in the article or core further toward the front of the article or core, where the term "after" means a position in the article or core further towards the back of the article or core.

'Co or used in the present invention, the term "z-dimension" refers to the dimension orthogonal to the length and width of the element, core or article. The dimension z generally corresponds to the thickness of the element, core or article. As used in the present invention, the term "x-y dimension" refers to the plane orthogonal to the thickness of the element, core or article. The dimensions x- and y- generally correspond to the width and length, respectively, of the element, core or article. The "crotch point" of an article and the absorbent core of the article is determined by placing the article on a user then placing the user in an upright position and then placing an extendable filament around the legs in a figure-eight configuration (see Figure 2). The point in the article and the absorbent core corresponding to the point of intersection of the filament is considered to be the midpoint of the article and the absorbent core. It is understood that the spacing point is determined by placing the absorbent article on a wearer in the manner proposed and determining where the cross filament would contact the article and the absorbent core. As mentioned in the present invention, the "crotch region" of an absorbent core corresponds to 50% of the total length of the absorbent core (ie, in the dimension y), where the crotch point is located at the longitudinal center of the crotch region. That is, the spacing region is determined by first locating the crotch point of the absorbent core, and then measuring a distance of 25% of the total length of the core back and forth. As used in the present invention, the term "skin width" refers to the width of the crotch region of the absorbent core that is narrowest when measured at the crotch point. When this layer consists of a plurality of discrete layers, the layer that has the most width pequ @ f | atí¡? * width of that layer, and therefore is the crotch width of the absorbent core. In case a layer is placed in profile in the cross dimension (x-), the width of that layer is determined by the width of the region of the highest base weight of the profile. As used in the present invention, the term "layers" refers to identifiable components of the absorbent structure, and any structure that is mentioned as a "layer" can effectively comprise a laminate or combination of several sheets or continuous materials of the required type of materials as described below in the present invention. As used in the present invention, the term "layer" includes the terms "layers" and "in layers". For purposes of this invention, it should also be understood that the term "upper" refers to the layer of the absorbent core that is closest to and facing the top sheet of the article; conversely, the term "lower" refers to the layer of the absorbent core that is closest to and facing the backsheet of the article. It should be noted that the various elements, layers, and structures of absorbent articles according to the present invention may or may not be of a generally planar nature, and may be formed or profiled in any desired configuration. Although the foregoing describes a segmentation of different regions of the article along the longitudinal center line of the article, an additional separation can be made along the lateral center line. Whereby, the region near the longitudinal centerline is referred to as the "central region," while the region on the outside of this region (that is, toward the lateral edges of the article) is referred to as the "regions". adjacent laterals ". An exemplary embodiment of an absorbent article according to the present invention is in the form of a diaper 20 having an absorbent core as shown in Figure 1. Figure 1 is a top plan view of the diaper 20 in a Static aforesaid, without contracting (i.e., with any withdrawn induced elastic contraction) having a top sheet 22, a back sheet 24, and an absorbent core that is generally indicated as being placed between the top sheet 22 and the top sheet 22. back sheet 24. The topsheet 22 is shown to be transparent to better illustrate the absorbent core 28. As shown also in Figure 1, the diaper 20 has an anterior waistband region 32, a waistband waistband region 34, crotch region 36 and a periphery 38 which is defined by the outer edge of the backsheet 24 and which has longitudinal edges which are designated 40 and end edges which are designated 42. The longitudinal axis of the diaper 20 extends essentially parallel to the longitudinal edges 40 and is represented as a longitudinal center line 67 (and corresponds to the direction or length y-), while the transverse axis extends generally in a direction parallel to the end edges 42 and is represented as the transverse center line 66 (and corresponds to the direction or width x-). The waistband regions 32 and 34 comprise those upper portions of the diaper 20 that, when the diaper is in use, surround the wearer's waist. The crotch region 36 of the article is that portion of the diaper 20 between the waistband regions 32 and 34, and comprises that portion of the diaper 20 that when in use, is positioned between the wearer's legs and covers the lower torso of the wearer. In this way, the crotch region 36 defines the typical liquid deposition area for a diaper 20 or other disposable absorbent article. The upper sheet 22 and the rear sheet 24 may be associated with each other preferably in the periphery only. As used in the present invention, the term "associated" comprises configurations where the top sheet 22 is directly attached to the back sheet 24 by attaching the top sheet directly to the back sheet, and configurations where the top sheet is indirectly attached to the back sheet by joining the top sheet to intermediate elements which in turn The posterior hf is imbedded. Preferably, the topsheet 22 and the backsheet 24 are attached directly to one another by a fixing means (not shown) such as an adhesive or any other fixing method as is known in the art. As shown in Figure 1, the topsheet 22 has a slightly smaller size configuration than the backsheet 24. However, the topsheet 22 and the backsheet 24 both can have the same size configuration (i.e. they are coextensive) to be joined together at the periphery 38 of the diaper 20. The size of the backsheet 24 is governed in part by the size of the absorbent core 28 and the exact diaper design that is selected. In the embodiment shown in Figure 1, the backsheet 24 has a configuration in the form of an hourglass. However, other configurations such as rectangular shape, "I" shape and the like are also suitable. Even when not shown, the diaper 20 may have elastic elements that exert a contraction force on the diaper so that it molds more closely and comfortably to the wearer. These elastic elements can be assembled in a variety of known configurations, such as those generally described in U.S. Patent No. 3,860,003 (Buell), issued January 14, 1975, the patents of which are incorporated by reference . The elastic elements may be placed adjacent the periphery 38 of the diaper 20, preferably along each longitudinal edge 40, so that the elastic elements tend to attract and hold the diaper 20 against the user's legs. Alternatively, the elastic elements may be placed adjacent either or both end edges 42 of the diaper 20 to provide a waistband as well as or instead of leg cuffs. See, for example, U.S. Patent No. 4,515,595 (Kievit et al.), Issued May 7, 1985, which is incorporated herein by reference. The elastic elements are fixed to the diaper 20 in an elastically condition tÉ ama ?? itM iníi-ri-fáí, ^ i¿¿ ^ contractile # 4 so that in a normally unrestrained configuration, these elastic elements effectively contract or pleat the diaper 20. The elastic elements can be fixed in a contractile elastic metrical condition in at least two ways. For example, the elastic elements can be stretched and fixed while the diaper 20 is in an uncontracted condition. Alternatively, the diaper 20 can be contracted, for example, by shirring, and the elastic elements can be fixed and connected to the diaper 20 while in their condition without relaxing or not stretched. The elastic elements can extend essentially the entire length of the diaper 20 in the crotch region 36, or alternatively they can extend the entire diaper 20, or any other suitable length to provide an elastically contractible line. The length of these elastic elements is typically dictated by the design of the diaper. Referring to Figure 1, the absorbent core 28 is represented as an "I" configuration. As indicated above, the absorbent core 28 will comprise the anterior and posterior regions, as well as a region of the core of the core (56). These regions are defined by determining the spacing point of the core 28 according to the description in the present invention. As discussed above, the crotch point is determined with reference to the user's anatomy. For purposes of illustration only, the midpoint of the core 28 is depicted as the detail 27 in Figure 1. The midpoint 27 is shown to be located on the longitudinal centerline 67 of the diaper 20 and the absorbent core 28. Generally this will be the case, whatever the configuration of the diaper and the absorbent core. However, as indicated, the midpoint 27 is not located on the transverse centerline 66 in this particular embodiment, although it may be in other diaper / core designs. As discussed above, as soon as the spacing point 27 of the absorbent core 28 is determined, the crotch region 56 is determine »by measuring forward from the crotch point a distance of 25% of the total length of the core (which is represented as the transverse line 61) and back from the crotch point a distance of 25% of the total length of the core (which is represented as the transversal line 63). In this illustration, the spacer region is the region of the core located between the transverse lines 61 and 63. As shown in FIG. 1, the absorbent core 28 is shown to have an anterior region 52, a posterior region 54, and a The skin region 56. Again, the crotch region 56 of the core 28 is dictated by the location of the skin point in the core. The crotch region of the core can be used to define the corresponding spawn region of the article. The topsheet 22 is preferably docile, of soft feel and non-irritating to the wearer's skin. Additionally, the top sheet is permeable to liquid allowing liquids (eg, urine) to easily penetrate through its thickness. A suitable top sheet can be manufactured from a wide variety of materials, such as porous foams; criss-crossed foams; plastic films with openings; or woven or non-woven fabrics of natural fibers (e.g., wood or cotton fibers), synthetic fibers (e.g., polyester or polypropylene fibers), or a combination of natural and synthetic fibers. Preferably, the topsheet is made of a hydrophobic material to isolate the wearer's skin from liquids contained in the absorbent core which is treated on one side with at least one surfactant material to allow liquids to easily penetrate through its thickness . At least a portion of the topsheet can be subjected to mechanical stretching for the purpose of providing a "null stretch" elastic laminate that forms the elastic side panels. To achieve this, the top sheet can preferably be stretched, more preferably pulled, but not necessarily elastomeric, so that the top sheet, when stretched ? OR mechanically, it will be stretched at least to some degree permanently so that it will not fully return to its original configuration. The upper sheet can be subjected to mechanical stretching in order to unduly tear or tear the upper sheet, whereby it is preferred that the upper sheet has a low yield strength in the cross-machine direction (lateral direction). There are many manufacturing techniques that can be used to make the top sheet. For example, the top sheet can be a non-woven fabric of fibers. When the top sheet comprises a nonwoven fabric, the fabric can be agglomerated by centrifugation, carded, wet laid, blown in the molten state, hydroentangled, combinations of the above or the like. A suitable top sheet is carded and thermally bonded by means well known to those skilled in the textile art. A preferred top sheet comprises regular length polypropylene fibers having a denier of about 2.2. As used in the present invention, the term "regular length fibers" refers to fibers that have a length of at least about 15.9 mm (0.625 inches). Preferably, the topsheet has a basis weight of about 18 to 25 grams / m2. A suitable topsheet is manufactured by Veratec, Inc., a division of International Paper Company, of Walpole, Massachusetts, USA, under the designation P-8. The top sheet 22 is placed on top of the body surface of the absorbent core 28. In preferred embodiments, an acquisition material is placed between the absorbent core 28 and the top sheet 22. The top sheet 22 may be attached to the absorbent core 28 and / or the backsheet 24 by fixing means (not shown) which are discussed in the present invention. Suitable attachment means are described below with regard to the attachment of the topsheet 22 and / or the backsheet 24 to the absorbent core 28. As used in the present invention, the The term "joined" encompasses configurations by means of which one element is fixed directly to another element by fixing the element directly to another element, and configurations by means of which the element is indirectly fixed to another element by fixing the element to intermediate element (s) which in turn is fixed to another element. In a preferred embodiment of the present invention, the upper and the backsheet are directly joined to one another at the periphery of the cloth and may be indirectly linked to one another according to the teachings discussed in the present invention. The topsheet may comprise a structured carrier material as disclosed in PCT publication WO 99/25288 (Roe), the disclosure of which is incorporated herein by reference. The structured carrier is docile, soft feeling, and non-irritating to the wearer's skin. Additionally, the structured carrier is permeable to liquid, allowing liquids (eg, urine) to easily penetrate through its thickness. A suitable structured carrier can be manufactured from a wide variety of materials, such as porous foams; criss-crossed foams; perforated plastic films; or woven or non-woven fabrics of natural fibers (e.g., wood or cotton fibers), synthetic fibers (e.g., polyester or polypropylene fibers), or a combination of natural and synthetic fibers. Preferably, the structured carrier is made of a hydrophobic material to isolate the wearer's skin from liquids contained in the absorbent core. Alternatively, the structured carrier can be treated with a surfactant to make it hydrophilic. The structured carrier preferably has a plurality of perforations with an effective perforation size of at least 0.2 square millimeters, more preferably, the plurality of perforations has an effective perforation size of at least 0.5 millimeters square, even more preferably, the Hi ^ gtf ¡g g ^ Plurality 4? § perforations have an effective perforation size of at least 1.0 square millimeters, and even more preferably, the plurality of perforations have an effective perforation size of at least 2.0 square millimeters. Effective perforations are those that have a gray level of 18 or less on a normal gray scale of 0-255 under the image acquisition parameters described in the aforementioned PCT publication WO 99/25288. The structured carrier preferably has an effective open area of at least 15 percent, more preferably the structured carrier has an effective open area of at least 20 percent, even more preferably, the structured carrier has an effective open area of at least 15%. at least 25 percent, and even more preferably the structured carrier has an effective open area of at least 30 percent. Carriers constructed in this way are particularly effective for receiving fecal matter, and provide a capacity through the top sheet of at least 1.3 g / cm2 when subjected to the ability to pass through the topsheet as described in EP-A-0J06,546, which is incorporated by reference in the present invention. The backsheet 24 is substantially impermeable to liquids (eg, urine) and is preferably made of a thin plastic film, although other flexible liquid impervious materials may also be used. As used in the present invention, the term "flexible" refers to materials that are compliant and easily conform to the general shape and contours of the user. The backsheet is intended to prevent the exudates absorbed and contained in the absorbent core from moistening the articles that come into contact with the tat diaper as sheets and undergarments. Thus, the backsheet may comprise a woven or non-woven material, polymeric films such as polyethylene or polypropylene thermoplastic films, or composite materials such as a non-woven material - i film coated. Preferably the backsheet is a thermoplastic material having a thickness of about 0.012 mm to 0.051 mm. In a particular embodiment of the present invention, at least a portion of the backsheet is subjected to mechanical stretching for the purpose of providing both an elastic "null stretch" laminate material forming the elastic side panels and, if desired, pre-stretch the portion of the back sheet that matches the elastic waist element or any other elastic element. For this, the backsheet can preferably be lengthened, more preferably pulled, but not necessarily elastomeric, so that the backsheet, being mechanically stretched, will be stretched to a certain extent permanently so that it will not fully return to its configuration original not distorted. In preferred embodiments, the backsheet can be subjected to mechanical stretching without undue tearing or tearing. Thus, it is preferred that the backsheet have a final stretch until break of at least 400% to 700%, approximately, in the cross machine direction as measured using a method consistent with ASTM D-638. . Thus, the preferred polymer films for use as the backsheet contain a high content of linear low density polyethylene. Particularly preferred materials for the rear hf include blends comprising about 45-90% linear polyethylene of low density and about 10-55% polypropylene. Exemplary films for use as the backsheet of the present invention are manufactured by Tredegar Industries, Inc. of Terre Haute, Indiana, USA, under the designations X-8323, RR8220 blends for certain blown films, and RR5475 blend for certain molded films. The backsheet 24 can be embossed (typically, to a caliper of approximately 0.127 mm and / or finished without gloss to provide an appearance more similar to the fabric. Additionally, the backsheet may allow the vapors to escape from the absorbent (ie, breathable) core while still preventing the exudates from passing through the backsheet. Examples of vapor permeable backsheet materials include microporous films, such as are available from Exxon Chemical, Texas USA, under the designation EXXAIRE® or laminates, monolithic films, such as are available from Elf AtoChem under the designation PEEBAX®, or from DuPont under the designation HYTREL®, or BF Goodrich under the designation ESTAÑE®, or laminates and laminated non-woven structures. The backsheet 24 is positioned adjacent the bottom surface of the absorbent core 28. Alternatively, an additional material (eg, an additional acquisition material) can be placed between the backsheet 24 and the absorbent core 28. The backsheet 24 can be fixed to the absorbent core 28 or any intermediate material by a layer of adhesive, preferably in a configuration as described below in the present invention. Alternatively, the fixing means may comprise heat bonds, pressure joints, ultrasonic joints, mechanical dynamic joints, or any other means of attachment or combinations of these suitable fixation means that are known in the art. The absorbent core 28 can comprise any absorbent material which is capable of acquiring, distributing and / or retaining liquids such as urine and certain other body exudates, and which is capable of providing good liquid handling capacity, which is generally expressed in terms of good acquisition, distribution and storage, particularly for urine, under conditions such as delivery speed, or volume as is typical for infants or adults. An operation of this type can be evaluated by methods well known in the art, such as the curved acquisition test and / or the rewet test as described in PCT application IB99 / 00741 (Case No. CM2060), which is expressly incorporated by reference in the present invention. According to this disclosure, and to the test methods as described herein, the preferred absorbent articles exhibit an absorbent capacity as determined by the vertical capillary absorption test of the entire article, wherein the capacities are determined by segments of the placed article. in vertical distance away from the line of folding of the article, and wherein the absorbent capacity for a segment at 13.5 cm is at least 0.5 times the capacity for the segment at 0 cm, preferably at least 0J5 times, more preferably 1.25, and even more preferably at least twice. Suitable absorbent articles can also be described by their respective crotch gauges, particularly the saturated skin gauge (SCC) and the actual wet crotch caliper (AWCC), which are determined following the curve acquisition test method, according to which the effective caliber of skin in wet state is inferior to the caliber of saturated crotch. The article preferably provides good rewet performance by exhibiting an after-curve rewet value of less than about 180 mg, preferably less than 150 mg, more preferably less than 90 mg. A suitable absorbent article can also be described as comprising an absorbent core, according to which the effective crotch caliber in the wet state as determined following the curved acquisition test method at the crotch point, is less than the effective gauge of the waist in the wet state, as determined following the curved acquisition test method at a waist point, and the article provides good rewet performance by exhibiting an after-curve acquisition rewet value less than about 180 mg.

As in a preferred design, the liquid storage region is located away from the liquid loading zone, the absorbent articles, or the components thereof, exhibit good liquid distribution functionality as described in detail in FIG. PCT publication 98/43580, which is expressly incorporated in the present invention. According to the teaching, an absorbent article comprises an absorbent core with a region of spandre and at least one waist region, whereby the aforementioned crotch region has a final liquid storage capacity of at least one. aforementioned waist region, whereby the crotch region additionally comprises a high flow liquid distribution material having a flow at 12.4 cm greater than 0. 075 g / cm2 / second, according to the vertical capillary absorption test as described in detail within the reference. Even though the absorbent core 28 is shown in Figure 1 in an "I" configuration, any shape can be used. For example, an absorbent core 128 is shown in Figure 3 in an "hourglass" configuration, wherein the core has arcuate cutouts at its longitudinal edges, which are indicated generally as 142. For purposes of illustration, the The spacing point is identified by detail 127. (As discussed above, the crotch point of the absorbent core is extrapolated from the user). As shown, the spacing point 127 generally lies on the longitudinal centerline 167 and on the transverse line (although not the transverse centerline in this embodiment) 168. The crotch region is determined by measuring forward from the crotch point a distance of 25% of the total length of the nucleus (which is represented as the transverse line 161) and back from the spacing point a distance of 25% of the total length of the nucleus (which is represented as the transverse line 163).

I? T? Lai? LÍÍÍÍÍ '' ^ ^ '^ * * The crotch region 156 is the region of the core between the transverse lines 161 and 163. In addition to the spacer region 156, the core 128 has an anterior region 152 and a posterior region 154. The crotch width of the absorbent core in The crotch point, when dry and when wet, is important to provide an improved fit to the wearer. It is preferred that the crotch width be small, even when wetted with liquid, so that the absorbent core experiences minimal clutter when the user's legs are closed. In this regard, the absorbent cores useful in the present invention will have a width of between when they are dry and optionally when they are moist no more than about 9 cm. Preferably, the crotch width when dry and preferably also when wet is not more than about 7 cm, even more preferably not more than about 5 cm, and more preferably not more than 3 cm. The width of the skin in the wet state can be measured by following the curve acquisition test described later in the present invention. Insofar as it relates to the problem of stacking during use, the crotch width may be more relevant than the cross-sectional area at the core spacing point. Furthermore, in this context, the narrowest dimension in the transverse dimension is considered to be the width layer of the spawn. It follows that a reduction in the crotch width of an absorbent core with a uniform capacity per unit surface area necessarily reduces the amount of material and capacity in the liquid deposition zone. Previous attempts to improve fit by reducing the width in the skin region were made by increasing the capacity per unit surface area to maintain the necessary capacity in the crotch region. Such previous attempts used additional fiber in the region of the skin for the absorption of liquid and in al§urfefe < : additional hydrogel-forming polymer rods for liquid storage. These methods therefore result in thicker absorbent cores, particularly in the crotch region, which in turn have a negative effect on the volume in both the dry and wet state. In direct contrast, the present invention has the purpose of displacing the liquid that is deposited in the region of the skin away from that region. This is reflected in the reduced level of liquid storage in the crotch region of the absorbent core. As such, in a preferred region of the present invention, the skin region of the absorbent core will comprise material (s) that function to distribute liquids away from the skin region. Although the distribution of liquid is an important function of the material of the core region of the core, it is within the scope of the invention to include materials in the crotch region whose main function is the storage of liquids, provided that the level of the liquid is not exceeded. storage required in the region of entrepiema. A particular aspect of the design of hygienic articles are the opposite requirements for functionality and comfort. Accordingly, low capacity items - such as the so-called "pantiprotector" - can be more easily designed with a desired level of softness than items that exhibit high absorbent capacity, such as baby diapers, or adult incontinence articles. Similarly, articles where materials exhibiting particularly good liquid transport and liquid retention properties are used, even under conditions of use such as increased pressures, often achieve this by increasing the inherent stiffness. The concept of "softness" is a well-known consideration for hygienic applications, and there are several methods to evaluate the subjective softness of certain materials and the resulting comfort of a user, by characteristics physical Most of these are linked to particular deformation characteristics of specific individual materials instead of the entire article as a whole. Thus, for many applications, the softness of an article can be evaluated by and achieved by a low caliber of the article and / or the liquid handling components that are used within it, but not for articles having increased caliber such as for more stringent liquid handling requirements. Accordingly, a major focus of the above developments has been to ensure that such materials exhibit good smoothness and it has been well established in the art, that various mechanical mechanisms exist that affect the impression of softness. The objective evaluation of the quality of the fabric was carried out / measured in the evaluation system Kawabata Evaluation System for Fabrics (KESF). An integrated system for the measurement of mechanical and surface properties of fabrics is commercially available. This equipment is designed to measure properties of low tensile stress, bending, shear stress and lateral compression of the fabrics, as well as surface friction and surface topography of the fabrics (Reference: S.

Kawabata, "The Normalization and Analysis of the Evaluation of the Touch", second edition ", The Textile Machinen / Society of Japan, 1980). A series of expressions are developed that are related to the touch components of the fabrics called "Main touch values (PHV)" (rigidity, freshness, antidrug, smoothness, and filling) and mechanical and superficial properties of the fabric. Expressions are also developed for the general classification of the fabric called "Total Touch Value" (THV) of the Main Touch Values. The KESF data is used for the analysis of fabrics. If these tests fully reflect all aspects of softness, it is open to discussion. However, the Kawabata series has limitations of the thickness of the * t ¿^ Í.Á¿A ^, i ^? ^., M ^ .. ^^. ^ ..,. ^ ,,, ^ m ^^^. ^, ^ J ^ íitJtí ^^ M M, material what can avoid the measurements of many types of articles related to the present invention. In view of such complexity, particularly these 17 parameters, many researchers focus on a few of these parameters, or according to the protocol that is described within or by a different protocol directed to the same or similar property. In this way, an important property that has been identified is the flexural strength, as measured in the TABER stiffness method (see test method T489 om-92, revised 1992), or the stiffness tests or GURLEY (see test method TAPPI 543), these two methods were originally designed for paper sheets, which were then reapplied for thin and flexible materials, such as fabrics, and therefore have significant undesirable limitations with respect to the thickness of the sample . Although such tests may be useful in varying degrees to evaluate different individual materials, they are significantly limited in the maximum thickness of a material or consequently of articles comprising thicker materials. In order to better describe the materials or compounds to be used in absorbent articles, which may have a thicker caliber, but still provide comfortable softness during use, it has been found that the "buckling / bending" test is particularly useful. This test combines the most relevant parameters and properties of complete sections of articles with which an evaluation of the softness of the article or compound versus the softness of the individual materials is allowed. This method takes into account all aspects of the structure of the articles and is therefore particularly suitable for high performance liquid handling articles. The key elements of this test are the "buckling resistance" and the (subsequent) bending deformation. ^ y ,,. AÍ¡A «MEB -; Í. itejA Accordingly, a comfortable article must exhibit some resistance to lateral compression deformation or buckling resistance in order to avoid excessive stacking of the article. The stacking generally refers to the deformation mechanism where the article is deformed during use in an uncontrolled manner, thus forming a rope-like structure, with arbitrary shape, excessive gauge or thickness and deteriorated operation. By contrast, the desired mechanism is to deform the article toward a curve concavely upwards (ie toward the user). As soon as the article has withstood the buckling deformation to a certain degree by controlled buckling, it can additionally be deformed in a controlled manner by further bending the arcuately deformed buckling. During this phase of bending, the deformation of the material defines the shape of the curve that initially exhibits a reduction in forces. Thus, for the subsequent deformation, the force required to deform the article after the initial buckling will be less than that required for the initial buckling. Accordingly, the article can withstand lateral forces without undue clutter, and will also reduce the propensity for unwanted pressure marks exerted on the wearer's body. When the "buckling / bending" test method is applied as described below in more detail in the present invention, the result of this test will be a diagram, which traces the deformation / deflection versus the corresponding force for the deformation / deflection determined. This curve will have - at least initially - a tendency towards "up", that is, for an increase in deformation the force will also increase. This can be a curve that increases in a "monotonic" way, that is, in mathematical terms, an increase in deformation will have a corresponding increase in force. This behavior includes the region - * "elastic" regular, where relieving the force, for example, the deformation will return to the starting point, but also for the "plastic deformation", where when relieving the extension force the original form is not resumed. The monotonically increasing curve can be observed for conventional articles, in particular where these comprise fabrics or layers, which are not joined together (eg, fluff pulp), but which are joined to each other in a layered configuration using conventional glue techniques. However, for articles according to the present invention, the curve generated in the bending / buckling test exhibits a maximum, i.e., within a certain deformation / deviation scale, in the increase of the deviation that will not result in an increase in the required force but rather it will result in a reduction of force. In mathematical terms, this maximum can be expressed by the curve that has a first zero derivative for this scale - and for deviation force values less than this maximum point, the derivative will be greater than zero, and for deviation values greater than maximum point, the derivative will have values less than zero. In particular, it has been found that these deformation properties are relevant for the region of the skin, where the liquid handling mechanisms have to be maintained, as well as for the anterior or posterior region, to establish and sustain a good fit. It should be noted that even if the individual components of a structure are soft and flexible, and have the buckling / flexing behavior described, the combination of these components can result in a significant increase in stiffness, as it can be more easily understood when considering, for example, corrugated cardboard. Within these, the action of gluing several flexible layers of paper results in a significant increase in stiffness. The articles according to the present invention must be made of materials or combinations of materials, that not $ ßrt excessively "rigid". This has to be satisfied without compromising the liquid handling properties. Thus, in the event that the article is made of several different materials, each of these materials must individually satisfy the buckling / bending requirements. In this way such materials may exhibit other desirable properties, such as compression softness (for example, for certain foams). As soon as suitable materials are selected, they have to be arranged so that they do not adversely affect the smoothness. This is particularly pertinent to the crotch region of the article where the need for efficient liquid transport is desired together with the desire to supply low volume of the structure. Additionally, this area is heavily influenced by the movements of the legs and the compression forces experienced when the legs come together. Given these movements it is preferred that this area exhibit the lowest force of the Buckling / bending test relative to at least one of the anterior or posterior regions of the article. For example, a material of high flowability can be disposed next to a storage material, provided that the other requirements are met. Additionally, materials should not be combined in such a way that the combination exhibits unacceptable structural softness. In particular, it has been found that the multilayer adhesive bond (as discussed in more detail later in the present invention) can have an important effect on softness, and can degrade it from initially very mild to very stiff. For the present invention, this refers to the union between two or more layers. The "bond" in this context of the present invention refers to permanent or temporary bonds (ie / for example, between manufacturing and first wetting in use).

A simple way to achieve the union is to compress two materials with one another, over a large area, or over parts thereof, so that a configuration is formed. In addition, bonding can be achieved by the application of adhesives or glues, also over a large surface area, or over parts thereof. In a preferred aspect of the present invention, the bond between two layers is designed to balance the requirement of good liquid communication between two adjacent surfaces, without creating excessive rigidity, such as allowing these two surfaces to move relative to each other without excessive friction Accordingly, this aspect of the present invention relates to particular binding configurations, as well as to surface properties for areas on the outside of these configurations. Permanent bonding is commonly achieved through the use of glues, or adhesives. In addition, it is commonly known to apply methods for such adhesives, which result in particular bonding configurations, the general classification being slot coating, application of glue beads as straight beads or as spiral beads, atomization of glue resulting in a Appearance similar to dots or similar to fibers. For all applications, there may be a total coverage of a certain surface, or the adhesive may be applied in a configured manner. Within the context of the present invention, the term configuration refers to at least two subregions of this determined surface, which can be differentiated by different applications of adhesive, such as coating or not of adhesive, atomization or not of adhesive, application or No adhesive beads, or - instead of "no glue" - have a different amount or type of different glue application.

^ H ^ In a subregion, to which glue has been applied, additionally there may be a region without glue - which can be best exemplified by considering an application of a glue applied by dots to a different configuration - between adjacent glue spots, there will be a glue-free subregion, however, such a region can easily be discerned from the region without any application of glue by atomization. Similarly, straight parallel glue beads will have a certain free glue stripe between them; however, a case where two or more pearls are configured next to each other, and in a spaced relation to an additional group of two or more pearls, the pearls grouped together will form a region, and the space between two groups will form the other region. In case the execution of the beads is not done in a straight application configuration, but - as for example, would be the case for the well-known "spiral glue application" - in a curved, or cycloid configuration (for example , generated by a rotating nozzle on a moving substrate), the width of this configuration will be defined by the diameter of this rotary movement. In the case of two spiral beads arranged next to each other, these can be in an overlapping configuration - thereby defining either a continuous zone with glue, or two glue zones with different levels of glue (where the spiral is superimposed and where it does not overlap) - or where the spirals can be separated from one another, with a glue application region, and a glue-free region. The adhesives that have been found satisfactory are manufactured by Century Adhesives, Inc. of Columbus, Ohio and marketed as Century 5227; and by H.B. Fuller Company of St. Paul, Minnesota and marketed as HL-1258.

Therefore, this particular aspect of the present invention relates to the specific arrangement of such joint configurations, to maintain the softness of a composite as high as possible without compromising the functional integrity of the article that is required for liquid handling . Although conventional articles generally shift the balance toward integrity operation and liquid, the present invention provides in this particular aspect an article, which is not attached across the width, but mainly in the central region, while the adjacent side regions are they leave substantially free of glue, and in this way can allow relatively easy movement of the two copies and thus allow low resistance to bending. The central region of the absorbent structure or article can be defined by measuring in both directions laterally from the longitudinal centerline an amount that is equal to 25% of the widest portion of the absorbent structure. The rest of the absorbent structure or article comprises the adjacent side portions. When it comprises particulate materials, they must be sufficiently fixed within the structure to avoid dislocation of the structure, or losses. Thus, preferably at least 80%, more preferably more than 95% of the particles, based on dry weight, are retained in such a structure upon shaking the structure. This can be done manually, such as by shaking it 60 times before 30 seconds, or this can be done by placing a sample of known dimensions, such as 10 cm by 10 cm, and known particle content on a conventional screening machine, such as a Tersch Vibro VS1000, with a vibration height of approximately 2 mm over a relatively large mesh, such as a 14 mesh with approximately 1.4 mm openings. The particles that fall shaking lili i i I n II jf ?? 111 * - - * -'- > * ™ i * 2 £ * & -ffo. they are entrapped in a suitable tray or plate, and the percentage of particles retained is determined. An additional means to arrive at structures or components useful for the present invention is described in PCT publication WO 99/42067 (McFall et al.), Which discloses a method for manufacturing a cracked or particulate absorbent material for an absorbent article such as towels. sanitary, diapers, incontinence devices, and the like. This method can be performed in place on another component of the absorbent article in a manufacturing process without cutting the other component. In one embodiment, the absorbent material is placed between two carrier fabrics, and tension is applied to the absorbent material composite and the carrier fabrics. The resulting tension and force break up the absorbent material, but only deforms the carrier fabrics to provide an integral fabric of particulate material between two carrier fabrics. Absorbent structures that are formed by this method are also disclosed. In one embodiment, the absorbent structure comprises a fabric composed of discrete elements of absorbent material. The composite fabric comprises at least one carrier fabric and a plurality of discrete elements of absorbent material arranged in an ordered array on the carrier fabric. In one embodiment, the discrete elements of absorbent material are placed adjacent to each other without any intermediate material between the discrete elements of the absorbent material. Example 1 This is an absorbent article comprising an absorbent core, which is depicted schematically in Figure 4, which shows a garment-side view of such an absorbent core, and Figure 5 shows a cross-sectional view of the absorbent core. an absorbent core of this type. The acquisition layer 701 of example 1 comprises a layer of chemically hardened cellulosic material. The acquisition layer 701 of example 1 has a longitudinal dimension of 260 mm and a transversal dimension of 60 mm. The basis weight of the acquisition layer 701 is 340 gsm resulting in a total weight of approximately 5.3 grams. The acquisition layer 701 is the layer that is located closest to the surface facing the user. Example 1 additionally comprises an anterior storage element 704 located in the anterior waist region 706 and a posterior storage element 708 located in the posterior waist region 707. In the example 1, the storage elements 704 and 708 are located in the surface facing the backsheet of the absorbent core and comprises the same type of material. The storage elements 704 and 708 comprise a polymer foam of open cells based on HIPE foams designed to store fluid. The above storage element 704 is substantially rectangular in shape, with the exception of the formed bottom edge 710, which has a width, transverse dimension of 130 mm and a length, longitudinal dimension, of 110 mm. The basis weight of the storage element 704 is 160 gsm resulting in a total weight of approximately 2.1 grams. The rear storage element 708 is substantially rectangular in shape, with the exception of the formed bottom edge 710, which has a width, transverse dimension, of 130 mm and a length, longitudinal dimension, of 188 mm. The basis weight of the rear storage element 708 is 160 gsm resulting in a total weight of about 3.8 grams. Example 1 additionally comprises a distribution element 703, which is located on the user-facing surface of the front and rear storage elements 704 and 708, and on the surface facing the backsheet of the storage elements 705 and 709 The distribution element 703 comprises a chemically bonded fibrous web treated after formation, according to the teachings of EP-A-0.810.078, except that the post-formation mechanical treatment was applied twice to the fabric before. mentioned. The element of distribution 703 extends from the anterior waist region 706 through the crotch region 702 and into the posterior waist region 707. The distribution element 703 is slightly formed to have a transverse dimension of 80 mm in the regions of anterior and posterior waist 706 and 707 and a transversal dimension of 60 mm in the crotch region 702. The longitudinal dimension of the distribution element 703 is 438 mm. The basis weight of the distribution element 703 is 120 gsm resulting in a total weight of approximately 3.9 grams. The distribution element is attached to the acquisition / distribution layer by conventional adhesives, such as are applied by spiral glue applicators only in the longitudinal central region, ie, without being laterally joined on the outside of this central region. Example 1 additionally comprises rewetting storage / barrier elements 705 and 709 located on the user facing surface of the distribution element 703 and the front and rear storage elements 704 and 708 and on the surface facing the back sheet of the element acquisition 701. The rewetting storage / barrier elements 705 and 709 comprise superabsorbent material adhesively bonded to the remaining core structure. The shape of the storage / barrier elements to the rewet has the approximate shape of the storage elements 705 and 708. The storage / barrier elements to the rewet 705 and 709 have a nominal weight of 300 gsm. This basis weight results in a total weight of 11 grams. Example 2 Example 2 is an absorbent article comprising an absorbent core of the present invention, which is also schematically depicted in FIG.

Figure 7, showing a view of the garment side of an absorbent core of this type, < .. ^ M¡ & and Figure 8 showing a cross-sectional view of an absorbent core of this type. The acquisition layer 701 of Example 2 comprises a layer of chemically hardened cellulosic fibers combined with a bicomponent fiber in a ratio of 87% to 13%, respectively. The acquisition layer 701 of Example 2 has a longitudinal dimension of 260 mm and a transverse dimension of 60 mm. The basis weight of the acquisition layer is 340 gsm resulting in a total weight of approximately 5.3 grams. The acquisition layer 701 is the layer that is located closest to the surface facing the user. Example 2 additionally comprises an anterior storage element 704 located in the anterior waist region 706 and a posterior storage element 708 located in the rear waist region 707. In the example 2, the storage elements 704 and 708 are located in the surface facing the backsheet of the absorbent core and comprise the same type of material. The storage elements 704 and 708 comprise a HIPE foam based on open cell polymer foam designed for liquid storage. The above storage element 704 is substantially rectangular in shape, with the exception of the formed inner edge 710 having a width, transverse dimension of 130 mm and a length, longitudinal dimension of 100 mm. The basis weight of the storage element 704 is 160 gsm resulting in a total weight of approximately 2.1 grams. The rear storage element 708 is substantially rectangular in shape, except for the formed inner edge 710 having a width, transverse dimension, of 130 mm and a length, longitudinal dimension, of 188 mm. The basis weight of the rear storage element 708 is 160 gsm resulting in a total weight of about 3.8 grams. Example 2 additionally comprises a distribution element 703 which is located on the user-facing surface of the elements of anterior and posterior storage 704 and 708 and on the rear hf facing surface of the rewetting storage / barrier elements 705 and 709. The distribution member 703 comprises a fibrous structure comprising chemically hardened, twisted, and crimped volume fibers , fibers of high surface area, and chemical binding additives. The dispensing member 703 extends from the anterior waist region 706 through the crotch region 702 and into the posterior waist region 707. The distribution element 703 is slightly formed to have a transverse dimension of 80 mm at the ends. anterior and posterior waist regions 706 and 707 and a transverse dimension of 60 mm in the spacing region 702. The longitudinal dimension of the distribution element 703 is 438 mm. The basis weight of the distribution element 703 is 120 gsm which results in a total weight of about 3.9 approximately. The distribution element is attached to the storage elements and barrier elements by conventional adhesives, such as are applied by spiral glue applicators only in the longitudinally central region, i.e., without being attached to the outside of this region. central. Example 2 further comprises rewetting storage / barrier elements 705 and 709 located on the user facing surface of the distribution element 703 and the front and rear storage elements 704 and 708 and on the surface facing the back sheet of the element of acquisition 701. The rewetting storage / barrier elements 705 and 709 comprise superabsorbent material adhesively bonded to the remaining core structure. The shape of the storage / barrier elements to the rewet has the approximate shape of the storage elements 704 and 708. The storage elements / rewet barrier 705 and 709 they have a total weight nominally of 300 gsm. This basis weight results in a total weight of 11 grams. METHODS OF TEST Method of volumetric softness This method has the purpose of measuring individual materials as well as structures that comprise these materials. Accordingly, this method can be used to evaluate regions of an article, such as anterior, posterior, or crotch region thereof. The method provides a correlation, such as can be plotted as a curve, between a value of volumetric smoothness (BS) in units of force [N] (y-axis) versus displacement in units of length [mm] (s) (X axis). Structures or articles suitable in accordance with the present invention will exhibit a continuous smooth curve along the scale of useful extensions, thus allowing the determination of the first derivative of that curve (d. {BS.}. / Ds), which frequently it is abbreviated as (BS ') (see Figure 7). The method uses a tensile tester in compression mode and a sample holder (Figures 6a and 6b) to measure the buckling force for a sample.

Traction Tester Apparatus A suitable traction tester is available from Zwick Company of Ulm, Germany, as Zwick Material Tester type 144560. Sample Holder The sample holder for this test is shown in Figures 6a and 6b. As can be seen in the Figures, the sample is held between two curvilinear plates (the curvature of the outer element of the support has a radius of 50 mm ± 1 mm with an arc length of 150 mm and the inner element has a radius of 54 mm. mm ± 1 mm with an arc length of 140 mm) that have tabs 30 mm wide that extend upwards 20 mm (anterior element) and 55 mm (posterior element) to allow the introduction of the sample holder into the jaws of the traction tester. The equipment is designed to test various thicknesses of materials from 1 mm to 10 mm. As can be recognized, sample holders of this type are necessary for both the upper and lower jaws of the tensile tester. Sample Preparation Prior to the test a sample is conditioned under controlled conditions (50% relative humidity, 25 ° C) for at least two hours. The sample is cut at 60 mm x 150 mm (± 2 mm per dimension). The dimensions of the sample, the short side versus the long side, should be consistent with the orientation of the material when it is used in a finished product (ie, in case the material in use has a short dimension and a long dimension then the sample must be cut so that the short side of the sample is the same relative side as in the total material). The sample of the skin region should be taken from the article along the longitudinal center line oriented so that 75 mm of the length of the sample is towards the anterior part relative to the crotch point and 75 mm of the sample is towards the back. Samples from the anterior and / or posterior region should also be obtained along the longitudinal center line with the length of 150 mm of the sample being measured along the longitudinal center line from or the end of the absorbent structure anterior or the end of the posterior absorbent structure, respectively. Samples of the anterior and posterior part may extend partially within the crotch region of the absorbent structure.

Installation of the Apparatus 1. The tensile tester is calibrated (in compression mode) according to the manufacturer's instructions. 2. The compression speed is set to 200 mm / minute. The crosshead stop point is set at 30 mm. 3. A sample is introduced into the sample holder to a depth of 7 mm ± 1 mm for each set of fasteners. 4. The spacing of the jaws of the tensile tester is set so that the unrestricted portion of the sample is smooth and without buckling. This corresponds to a separation between the upper and lower portions of the 46 mm sample holder.

Operation v Data Compilation 1. The sample / sample holder assembly is inserted into the jaws of the tensile tester. 2. The tensile tester operates in compression mode to record a force / compression curve for each sample. 3. The buckling force is recorded for each sample. The buckling force is the force that is required to cause the sample to initially begin to buckle. It is the initial maximum force that is observed on the force / compression curve before a plateau of relatively constant force that is a measure of the flexural strength of the sample (bending force). 4. Steps 1-3 are repeated for at least 5 samples for each structure being tested and the average and normal deviation of the buckling force is reported. Determination of Curves and Derivatives Referring to Figure 7, a typical result for the structures and components as shown, where, in the region that is represented as "A" the Buckling mechanism is carried out, which changes to a bending mechanism in the region that is represented as "B" with a reduction in force after the maximum at the transition point from "A" to "B". This transition point also corresponds to the point where the first derivative of the curve is zero. Determination of the crotch point Figure 2 illustrates the means to determine the crotch point of an article and its absorbent core. Referring to Figure 2, the legs of a standing user are depicted in cross section as 301 and 302. A continuous 303 material (e.g., a twine or elastic band) is twisted once and is placed around the legs of the user at a point sufficiently close to the user's torso so that the intersection 304 of the material 303 can be extrapolated onto the article being used. The crotch point of the core of the article is determined in such a way, and the crotch region of the core is determined according to the above description. Additional evidence Particular reference is made to PCT application IB 99/00741 (Case No. CM-2060) in particular with regard to the following methods as described in detail in the Test Method section thereof: Synthetic urine formulation acquisition curve Acupressure Collagen Rewet Method Posterior Curve Absorbent Core Capacity and Crotch Capacity of Absorbent Core by Tea Bag Centrifugal Capacity Method (TCC Test) Caliber Measurement Method Capillary Sorption Test Vertical Capillary Absorption Test of the total article Vertical capillary absorption test of distribution materials

Claims

CLAIMS 1. A disposable absorbent article, the aforementioned article comprises a region of skin to be placed between the user's legs during its intended use, and at least one end region, the aforementioned article comprising a first composite material comprising a top sheet , a back sheet, and an absorbent structure therebetween, at least in parts of the aforementioned crotch and end regions, according to which at least the top sheet and the back sheet are joined together, which is characterized in that the first composite material exhibits a force of volumetric smoothness for the crotch and end regions. { BS} versus displacement. { s} , which can be expressed as a mathematical curve, for which a derivative (d (BS) / ds) = (BS ') can be determined, whereby for the first aforementioned composite material in at least one of the regions aforementioned the aforementioned derivative has at least one displacement value (s0) a value of zero, where the above-mentioned displacement value (s0) leaves the composite exhibits a value of force of volumetric smoothness (BS. s0.}.) less than 10 Newton, preferably less than 7.5 Newton and even more preferably less than 5 Newton. An absorbent article according to claim 1, wherein the aforementioned volumetric softness value of the aforementioned first composite material for the displacement values where the derivative of the volumetric softness curve is equal to zero (BS. s0.}.), is lower in the crotch region than in an end region. 3. An absorbent article according to any of claims 1 or 2, wherein the first composite material mentioned above has a - ri¡nr H í *? tiíf? volumetric softness value in an end region less than about 5 Newton, preferably less than 3 Newton. 4. An absorbent article according to any one of claims 1 to 3, wherein the aforementioned absorbent structure comprises a capillary absorption layer. An absorbent article according to claim 4, wherein the aforementioned capillary absorption layer has a volumetric softness value of less than 3 Newton, preferably less than 1 Newton. 6. An absorbent article according to claim 4 or 5, wherein the aforementioned capillary absorption layer is a fibrous web treated by a post-formation activation treatment. 7. An absorbent article according to claim 6, wherein the aforementioned subsequent activation treatment is a double-step activation. 8. An absorbent article according to any of the preceding claims, wherein the aforementioned absorbent structure comprises an acquisition region. 9. An absoibent article according to claim 8, wherein the aforementioned acquisition region comprises a material exhibiting a value of volumetric smoothness of less than 3 Newton, preferably less than 1 Newton. An absorbent article according to any of the preceding claims, wherein the aforementioned absorbent structure comprises a second layered absorbent material, comprising at least one support layer, comprising particles capable of absorbing liquid, attached to the support layer mentioned above. 11. An absorbent article according to claim 10, wherein the aforementioned particles are selected from the group of materials consisting of superabsorbent gelling polymers, polymeric foam materials, and combinations thereof. 12. An absorbent article according to claim 10 or 11, wherein the aforementioned second layer absorbent composite comprising the aforementioned particles is discontinuous, which has at least two composite regions separated longitudinally from one another. An absorbent article according to any of claims 10 to 12, wherein the aforementioned second layer absorbent composite comprising the aforementioned particles is placed in at least one of the end regions of the aforementioned article. 14. An absorbent article according to any of claims 10 to 13, wherein the aforementioned second layer absorbent composite comprising the aforementioned particles is placed in the region of the subsequent article. 15. An absorbent article according to any of claims 10 to 14, wherein the aforementioned support layer is selected from the group of materials consisting of tissue paper structures, non-woven materials, woven materials or spongy structures. 16. An absorbent article according to any of claims 10 to 15, wherein the aforementioned particles are bonded to the aforesaid support layer by means of a joining means. 17. An absorbent article according to claim 16, wherein the attachment means is a meltblown hot melt adhesive. 18. An absorbent article according to any of claims 10 to 17, wherein the aforementioned particles are immobilized by more than about 80%, and based on the dry weight, preferably more than about 95%. 19. An absorbent article according to any of claims 10 to 18, wherein the basis weight in the particles is greater than 100 g / m2, preferably more than 300 g / m2, more preferably more than 500 g / m2. An absorbent article according to any of the preceding claims, wherein the aforementioned absorbent structure provides an absorbent capacity, so that the aforementioned crotch region has a final absorbent capacity, which is less than 55% of the Total final absorbent capacity of the aforementioned absorbent structure. 21. An absorbent article according to any of the preceding claims, wherein the aforementioned article has a stitch point in the aforementioned crotch region, and wherein the final absorbent capacity of the aforementioned absorbent structure which is positioned towards behind the aforementioned crotch point is greater than about 60% of the final total storage capacity of the article. 22. An absorbent article according to any of the preceding claims, wherein the aforementioned absorbent structure has two central regions aligned on each side of the longitudinal centerline of the aforementioned article, and two adjacent lateral regions positioned laterally outwardly from each other. respective central regions mentioned above, each of the aforementioned adjacent side regions extends to a width of 25% of the widest portion of the absorbent structure outwardly of the aforementioned central regions; The aforementioned absorbent structure comprises at least two you tSM ' layers of absorbent material that are in a contact relationship, thereby defining a common contact surface area; wherein the two aforementioned layers are joined together by joining means covering an area of attachment means, which is less than the aforementioned common contact surface area; so that at least 75% of the aforementioned bonding media area is located within the region of the central core. 23. An absorbent article according to claim 22, wherein the aforementioned joining means is a hot melt adhesive.