MXPA97005096A - Absorbent article with ap waist characteristics - Google Patents

Abstract

Absorbent articles having a supporting waist feature are provided. In its preferred embodiment, the support waist feature expands upon exposure to aqueous body fluids, effectively tightening the diaper by stretching the waist regions of the absorbent article. There is a resultant increase in contractive forces in the lateral tension band in the waist regions of the absorbent article with a corresponding reduction in risk of waist leakage. The support waist feature further provides a member that resists longitudinal bending in the waist regions of the absorbent article, particularly adjacent to the wearer's belly. This member can also act as a "strut" that resists forces such as those due to gravity, which tend to cause the absorbent article to slide downward. The absorbent article is additionally provided with an absorbent core comprising at least one redistribution component that is preferably capable of redistributing the aqueous body fluids from the crotch region to the waist regions of the absorbent article. The redistribution component is in effective fluid communication with the waistline characteristic of the

Description

ABSORBENT ARTICLE WITH WAIST CHARACTERISTICS SUPPORT FOR FIELD OF THE INVENTION The present invention relates to absorbent articles such as diapers, training pants, incontinence briefs and the like, and more particularly to absorbent articles having a waist feature that provides dynamic fit around the wearer during the entire cycle of use of the article. absorbent, as well as improved containment characteristics for the absorbent article.

BACKGROUND OF THE INVENTION Babies and other incontinent individuals use absorbent articles such as diapers to receive and contain 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, United States Patent Re. 26,152 issued to Duncan and Baker on January 31, 1967, describes a disposable diaper that has achieved widespread acceptance and commercial success. U.S. Patent No. 3,860,003 issued to Buell on January 14, 1975, describes a disposable diaper with elasticized leg cuff which has achieved wide acceptance and commercial success. However, absorbent articles of the current art have a tendency to bulge or hollow away from, and to slide / detach down the user's body during use. Three failure modes have been identified that contribute to this hollowing, bulging, sliding, and detachment. 1) The forces exerted by the normal movement of a user as the user breathes, moves and changes position, can cause the waist region of a diaper to roll up during normal use, resulting in a reduced packing effect in the waist. 2) The normal movement of a user can cause the lateral tension band created by the fastening system of the absorbent article to move downwardly under the belly towards the crease of the wearer's belly. This is because of the fact that for an irregularly formed volume, a tension band will look for the cross section that has a minimum circumference for this volume. Typically, absorbent articles are fastened around the wearer's waist at or near the wearer's navel, while the minimum circumference around the wearer goes through a point under the wearer's belly, in the crease of the belly, and through from a point in the narrow part of the back. As a result, the tension band will tend to move towards this minimum circumference line. The downward force generated when the absorbent article is loaded with body exudates also contributes to this slip / detachment. 3) Deformation of the absorbent article materials by itself. For example, the elastic elements in a diaper are subject to a property, known as tension relaxation, which is inherent in polymer systems, such as are used as the elastic member in elastic elements of the diaper technique to provide a band of tension around the user's waist. That is, the contractive force exerted by an elastic member decreases with time, resulting in a decrease in the force exerted by the tension band around the wearer's waist, and, in addition, contributes to the aforementioned bulging, cupping or slipping. . In addition, the discussion of stress relaxation can be found in many texts on polymer science, for example: Billmeyer Jr., F.W., Textbook of Polvmer Science. Jhon Wiley & Sons, pp 188-190. The net effect of this bulging, cupping, slipping and detachment, may be premature leakage and poor fit of the absorbent article around the user, particularly in the waist regions of the absorbent article. In order to engage in premature leakage in the waist regions of the absorbent articles, certain commercially available absorbent articles have been provided with elastic waist features. Such elastic waist features cause the absorbent article to fit more comfortably around the wearer's waist. An example of a disposable diaper with an elastic waist feature that has achieved wide acceptance and commercial success is described in U.S. Patent No. 4,515,595 issued to Kievit et al. On May 7, 1985. Typically, waist characteristics elastic will comprise an elasticized waistband consisting of an elastic member fixed contractibly between the topsheet and the backsheet, at the ends of the absorbent article. The elasticized waistband is thus designed to expand and contract with the movements of the wearer and to maintain the fit of the absorbent article around the wearer's waist during use (i.e., provide sustained dynamic adjustment). However, it has been found that absorbent articles having such an elastic waist feature designed to fit at or near the navel, also have a tendency to bulge, hollow, slide or peel off during use. In addition, the aforementioned elastic waist feature has a tendency to wrap around the front of the diaper resulting in a loss of fit around the wearer's waist. For male users, in particular, coiling in the front increases the risk of waist leakage, since the male urine stream is often directed towards the waist due to the male anatomy. In this way, it would be advantageous to provide an absorbent article having a waist feature that provides improved fit, reduced leaks, and increased comfort to the wearer. In addition, it would be advantageous to provide an absorbent article having reduced bulging, cupping and coiling at the front, at the waist of the diaper also as reduced overall shedding / detachment of the absorbent article or absorbent core on the wearer during use. Therefore, it is an object of the present invention to provide an absorbent article having sustained dynamic fit around the wearer's waist during use. It is a further object of the present invention to provide an absorbent article having a unique support waist feature that provides sustained dynamic fit and improved resistance to leakage during use. It is yet another object of the present invention to provide an absorbent article having a unique support waist feature that reduces cupping, bulging or wrapping in front of the diaper front, as well as slippage, overall detachment of the absorbent article or the absorbent article. Absorbent core during use. It is still a further object to provide an absorbent article having a unique support waist feature that compensates for the loss of fit due to the relaxation of the tension of the elastic components, which provides tension around the waist region of a wearer. These and other objects of the present invention will be more readily apparent when considered in reference to the following description and when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE INVENTION The present invention provides absorbent articles such as diaper, disposable diapers, incontinence briefs, training pants and the like, which have a unique support waist feature that improves the dynamic fit of the absorbent article and reduces the risk of premature leakage in the waist. A preferred absorbent article of the present invention comprises a containment assembly preferably comprising a liquid-permeable top sheet, a liquid-impervious backsheet, an absorbent core positioned between the top sheet and the backsheet, an attached support waist feature longitudinally between a first transverse end of the absorbent core and a first transverse end of the absorbent article, and a fastener system for creating / maintaining lateral tension through at least a portion of the circumference of the absorbent article. In its most preferred embodiment, the supporting waist feature is unitary with the absorbent core and the absorbent article of the present invention is further provided with pairs of lateral fins, which extend laterally from the longitudinal edges of the containment assembly in both waist regions of it. Preferably, the lateral fins provided in the second waist region are elasticized. The support waist feature provides a member that resists longitudinal bending in the waist region of the absorbent article of the present invention. Resisting flexion, the support waist feature reduces the risk of waist leakage due to rolling and bulging, particularly in the waist region. The support waist feature further cooperates with the core to resist loss of fit due to downward movement of the waist of the absorbent article. The supporting waist feature and the absorbent core cooperate to form a "strut" that resists those forces such as body movement and load with body exudates that tend to cause the waist of the absorbent article to move downward. The supporting waist feature also further compensates for the loss of the contraction force over time in the tension band, which exists in the waist regions of the absorbent article, due to the relaxation of the tension of the polymer components, in particularly the elastic members that provide the tension. This loss of contraction force can cause slippage with the increased risk of premature leakage. The support waist feature of the present invention is able to compensate for this loss of contraction force because its thickness is increased, i.e., the gauge increases as it becomes saturated with the aqueous body fluids. This thickening results in an increase in the circumference of this portion of the absorbent article around which the tension band acts, and, therefore, an increase in the elongation of the elastic member resulting in an increase in the contraction force provided. by the elastic member. The absorbent core of the present invention may further comprise at least one redistribution component that is capable of redistributing aqueous body fluids from the crotch region of the absorbent article (adjacent to a user's fluid discharge regions). ) at least one of the first or second waist regions of the absorbent article. The absorbent core of the present invention is in effective fluid communication with the supporting waist feature such that, as the aqueous body fluids are absorbed, they are redistributed to the supporting waist feature enabling it to expand in an alternate mode of the present invention, the absorbent article is provided with longitudinal edges joined in at least the waist regions instead of a fastening system. Such a modality is useful as a training pant, a diaper that goes up or similar.

BRIEF DESCRIPTION OF THE DRAWINGS Although the description concludes with the claims particularly pointing out and clearly claiming the subject matter that is considered as forming the present invention, it is believed that the invention will be better understood from the following description which is taken in combination with the accompanying drawings , in which like designations are used to designate substantially identical elements, and in which: Figure 1 is a plan view of a disposable diaper embodiment of the present invention having portions cut away to relieve the underlying structure, and with the surface inside of the diaper facing the observer. Figure 2 is a fragmentary, expanded sectional view of the absorbent insert of Figure 1, taken along section line 2-2 of Figure 2. Figure 3 is a partial side view of a baby using a disposable diaper embodiment of the present invention, showing the preferred location of the absorbent core and of the support waist feature in a wearer. Figure 4 is a partial front view of a diaper of the present invention while, being in use, showing how the supporting waist feature and the core cooperate to inhibit sliding or downward movement. Figure 5 is a diagrammatic representation of the contraction force against time for an elasticized feature of the present invention, showing how the elastic waist feature of the present invention counteracts the loss of the contraction force due to stress relaxation .

DETAILED DESCRIPTION OF THE INVENTION As used herein, the term "absorbent article" refers to devices that absorb and contain body exudates, and, more specifically, refers to devices that are placed against or close to the user's body to absorb and contain the various discharges of exudates from the body. 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 (i.e., are intended to be discarded after a single use, and, of preference, to be recycled formed in behaves or otherwise disposed of 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 such that they do not require separate manipulated parts such as a separate liner and fastener. A preferred embodiment of the absorbent article of the present invention is the unitary disposable absorbent article, diaper 20 shown in Figure 1. As used herein, the term "diaper" refers to an absorbent article generally worn by infants and incontinent persons which is used around the user's lower torso. However, it should be understood that the present invention is also applicable to other absorbent articles such as incontinence briefs, incontinence underwear, training pants, diaper inserts, and the like. In its simplest form, an absorbent article of the present invention need only include an outer cover, such as a backsheet (typically relatively liquid impervious), an absorbent core associated with this outer cover, a support waist feature in communication of effective fluid with this absorbent core, and means for creating lateral tension through at least a portion of the waist region of the absorbent article. The absorbent core is capable of transporting aqueous body fluids from the crotch region of the absorbent article to at least one of the waist regions thereof. The absorbent core and the backsheet will be associated in such a way that the absorbent core is located between the backsheet and the fluid discharge region of the wearer of the absorbent article. The support waist feature provides resistance to longitudinal bending or bending in the waist regions of the absorbent article, providing the placement and sharp adjustment. Furthermore, the support waist feature is capable of increasing the lateral tension in the waist regions of the absorbent article as it becomes saturated with the aqueous body fluids, counteracting the loss of the contraction force due to the relaxation of the tension of the absorbent article. the elastic elements in there. As used herein, a diaper component becomes "saturated" with aqueous body fluids after an amount of aqueous body fluid having a weight that is equal to at least 8 times the weight of the component has been absorbed. or if the component can not absorb 8 times its weight of aqueous body liquid, the component is said to be saturated if it has absorbed at least 50% of its maximum absorption capacity of the aqueous body fluid. The means for creating the lateral tension in the waist region provides the force that holds the absorbent article around the wearer's waist. Examples of such means include, but are not limited to, a belt system with a landing zone, the belts in said belt systems may be either elasticized or non-elasticized, a mechanical fastening system, elasticized side panels and waist characteristics. elastified or combinations thereof. Figure 1 is a plant in view of a preferred embodiment of the present invention, the diaper 20. The diaper 20 is shown in its non-contracted, flat state (ie, with the contraction induced by the elastic pulled outward), with portions of the structure being cut to more clearly show the construction of the diaper 20 and with the portion of the diaper 20 that gives or contacts the wearer, the interior surface, facing the viewer. As shown in Figure 1, the diaper 20 comprises a containment assembly 22 preferably comprising a liquid-permeable top sheet 24, a liquid-impermeable back sheet 26, bonded to the topsheet 24.; an absorbent core 28 positioned between the topsheet 24 and the backsheet 26; Elastic leg folds 32; a characteristic of elastic waist 34; a multiple fastener system designated 36; and a support waist feature 38. The preferred embodiment of the diaper 20 of the present invention shown in Figure 1 still further comprises pairs of side panels 30 and 40 attached to and extending laterally from the containment assembly 22. In the most Preferred of the present invention at least a part of the pair of side panels 40 is elasticized. The diaper 20 is shown in Figure 1 having an outer surface 64, an inner surface 60 opposite the outer surface 64, a first waist region 42, a second waist region 44 opposite the first waist region 42, and a crotch region 46 positioned between the first region of waists 42, and the second waist region 44, longitudinal edges 54 and end edges 56. The inner surface 60 of the diaper 20 comprises that portion of the diaper 20, which is positioned adjacent to the body of the user during use (i.e., the inner surface 60 is generally formed by at least a portion of the topsheet 24 and other components attached to the topsheet 24).

The outer surface 64 comprises that portion of the diaper 20 which is positioned away from the wearer's body (i.e., the outer surface 64 is generally formed by at least a portion of the back sheet 26 and other components attached to the back sheet 26) . The diaper 20 also has two centerlines, a longitudinal centerline 100 and a transverse centerline 102. The term "longitudinal", as used herein, refers to a line, axis or direction in the diaper plane 20 is generally aligned with, i.e., approximately parallel with a vertical plane that divides a user standing in left and right halves when the diaper 20 is worn. The terms "transverse", "lateral" as used herein, are interchangeable and refer to a line, axis or direction which lies within the plane of the diaper that is generally perpendicular to the longitudinal direction (ie, divides the user into front and back body halves). The containment assembly 22 is shown in Figure 1, having a periphery 50, which is defined by the outer edges of the containment assembly 22, in which the edges are designated the longitudinal edges 52. The periphery 50 of the containment assembly 22 further comprises those portions of the end edges of the diaper 56 that lie laterally between the longitudinal edges 52. Figure 1 shows a preferred embodiment of the diaper 20 in which the backsheet 24 and the backsheet 26 have length and width dimensions generally greater than those of the absorbent core 28. The topsheet 24 and the backsheet 26 extend beyond the edges of the absorbent core 28, thereby forming the periphery 50 of the containment assembly 22. Although the topsheet 24 as the backsheet 26, and absorbent core 28 can be assembled in a variety of well-known configurations, preferred diaper configurations are generally exhibited in the United States patent 3,860,003 which was issued to Cande B.

Buell on January 14, 1975; and U.S. Patent 5,151,092 issued to Kenneth B. Buell et al. on September 29, 1992; the disclosure of each one being incorporated herein by reference. Figure 2 is an enlarged, cross-sectional view of the diaper 20 taken along the section line 2-2 of Figure 1, showing details of the support waist feature 38. As shown in Figure 2 , the preferred embodiment of the supporting waist feature 38 is an extension of the fluid redistribution component 29 and comprises 3 layers of absorbent foam 39a-39c. Also shown are the components of a preferred embodiment of the absorbent core 28, the fluid acquisition component 27 and the fluid redistribution component 29.

Also shown is a waist protector 37, which is disposed between the support waist feature 38 and the top sheet 24. The absorbent core 28 can comprise any absorbent means that is generally compressible, conformable, non-irritating to the wearer's skin. , and capable of absorbing and retaining liquids such as urine and other certain body exudates. As shown in Figure 1, the absorbent core 28 has a garment surface, a body surface, side edges, and first and second waist edges 58a and 58b. The absorbent core 28 can be manufactured in a wide variety of sizes and shapes (e.g., rectangular, hourglass, T-shaped, asymmetrical, etc.), and from a wide variety of liquid absorbing materials commonly used in disposable diapers 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; melt-blown polymers including coform; non-woven fabrics, such as those formed using capillary channel fibers; chemically hardened, modified or interlaced cellulosic fibers; tissue including tissue wraps and tissue laminar units; absorbent foams; absorbent sponges, absorbent polymers; gelling absorbent materials; or any equivalent materials or combinations of materials. The configuration and construction of the absorbent core can also be varied (eg, the absorbent core can have a variable gauge zone, a hydrophilic gradient, a super absorbent gradient, or lower average weight basis acquisition areas, lower average density; may comprise one or more layers or structures). The total absorbent capacity of the absorbent core 28, however, must be compatible with the design load and intended use of the diaper 20. Also, the size and absorbent capacity of the absorbent core 28 may be varied to suit users ranging from babies to adults. In addition, the first waist edge 58a of the absorbent core must be in effective fluid communication with the support waist feature 38 of the diaper 20. As used herein, the term "effective fluid communication" is intended to be understood. that aqueous body fluids, particularly urine, can be distributed from one component of the diaper 20 to another by capillary forces, osmotic forces or other liquid transport mechanisms. The absorbent core 28 should also be capable of distributing sufficient liquid to the support waist feature 38 to enable the expansion of the support waist feature 38 as it is being deserved with these liquids. Exemplary absorbent structures for use as the absorbent core 28 are described in U.S. Patent 4,610,678 issued to Weisman on September 9, 1986; U.S. Patent 4,888,231, issued to Angstadt on December 29, 1989; U.S. Patent 4,834,735, issued to Alemany et al. on May 30, 1989; and U.S. Patent 5,318,554 issued to Young et al. on June 7, 1994. The disclosure of each of these patents is incorporated herein by reference. The vertical wicking effect, that is, the wicking effect of the fluid in an opposite direction of gravity, is an especially desirable developmental attribute for the absorbent cores described herein. This is because such absorbent cores will often be used in absorbent articles in a manner such that the aqueous liquids of the body that are absorbed must be moved into the article from a relatively lower position to a relatively greater position within the absorbent core of the article. For example, the diaper 20 of the present invention also comprises a support waist feature 38, described in detail below, which, as it becomes saturated with aqueous body fluids, increases in volume providing increased resistance to bending or bending in the longitudinal direction and decreasing the lateral tension in the waist regions 42 and 44 to compensate for the loss of lateral tension due to the relaxation of the tension of the elasticized elements of the diaper 20. With the purpose that the aspects of expansion of the supporting waist feature to be operative during the full extension of the user's movements, the absorbent core 28 must be able to redistribute the aqueous body fluids that could be absorbed in the crotch region 46 at least one of the first waist region 42, second waist region 44 or both waist regions. In this way, the vertical wicking effect enables this redistribution for examples when the waist regions 42 and 44 are relatively larger than the crotch region 46 (e.g., when the user is sitting or standing). Methods for measuring vertical wicking properties of diaper core components are described in the TEST METHODS section of copending US patent application Serial No. 07 / 989,270 (Dyer et al.), filed on December 11, 1992, the disclosure of which is incorporated by reference. As shown in Figure 2, a particularly preferred embodiment of the absorbent core 28 comprises a fluid acquisition component 27 and a fluid redistribution component 28. The fluid acquisition component 27 can comprise any hydrophilic porous material which will imbibe and will distribute the aqueous body fluids. Frequently, such absorbent materials are nature-based foam or fiber-based. The fluid redistribution component 29 may comprise any of the materials discussed above as being appropriate for the absorbent core 28 while the fluid redistribution component 29, alone or in combination with the acquisition component 27, provides the absorbent article 28 with those vertical wicking properties that allow it to make the expansion aspects of the support waist feature 38 capable. A preferred embodiment of the fluid redistribution component 29 comprises at least one layer of the absorbent foam material described in the United States 2,268,224 issued to DesMarais et al. on December 7, 1993, the disclosure of which is incorporated herein by reference. Absorbent foam materials of the type described therein are preferably manufactured by polymerizing high internal phase oil-in-water emulsions (HIPE foams). These will typically have a free absorbent capacity of from about 20 to about 100 ml / g and a specific surface area per volume of foam of at least about 0.025 m2 / cm 3. As used herein, the term "free absorbent capacity" refers to the total amount of the test fluid (Jayco synthetic urine) which a given sample of foam will absorb into its cellular structure per unit mass of solid material in the sample and the term "surface area per volume of foam" refers to the specific area of the capillary suction surface of the foam structure multiplied by its foam density in the expanded state. Preferred absorbent foams of the present invention which are especially useful in absorbent articles for absorbing urine, will also generally have a capillary absorption pressure of at least about 24.1 cm, preferably at least about 30 cm and most preferably at least 40 cm. cm. As used herein, the term "capillary absorption pressure" is the height at which the absorbing capacity of the vertical wicking effect is at 50% of its free absorbent capacity. Methods for measuring most of these properties are described in the TEST METHODS section of copending United States patent application Serial No. 07 / 989,270 (Dyer et al.), Filed on December 11, 1992, disclosure. of which is incorporated by reference. The procedure for determining the free absorbent capacity of the foam is described later in the Test Methods section. The particularly preferred absorbent core 28 shown in Figure 2 has a fluid redistribution component 29 comprising 3 layers of the HIPE foam described above. Additional details with respect to absorbent cores 28 of this type are disclosed in U.S. Patent 5,318,554, issued Young et al. On June 7, 1994, the disclosure of which is incorporated herein by reference. These preferred absorbent foam structures will often be used in absorbent articles together with other types of absorbent structures that may also participate in the acquisition and / or storage of aqueous fluids. In these contexts, wherein the absorbent foam structures herein are primarily intended to assist as a fluid redistribution component in absorbent articles, it is desirable that such foams have a tendency to pull aqueous body fluids toward such a redistribution component from other components. absorbers, such as an acquisition component that also absorbed said fluids.

Such a tendency to dewater the fluids of other components of the absorbent article is known in the art as "repartition". The concept of distribution and certain procedures for determining the development of the distribution are described, for example, in the aforementioned U.S. Patent 4,610,678. When it is tested for the development of distribution using procedures similar to those disclosed in the patent of the United States 4,610,678 these preferred absorbent foam structures exhibit particularly desirable fluid distribution characteristics. The backsheet 26 is positioned adjacent to the garment surface of the absorbent core 28. The backsheet 26 prevents the exudates absorbed and contained in the absorbent core 28 from wetting the articles that come in contact with the diaper. such as sheets and undergarments. The back sheet 26 > it is typically impermeable to aqueous body fluids (eg, urine) and is preferably manufactured from a thin plastic film, although other flexible liquid-impermeable materials may also be used. As used herein, the term "flexible" refers to materials that are docile and will readily conform to the shape and general contour of the human body. The backsheet 26 can thus comprise a woven or non-woven material, polymeric films such as polyethylene and polypropylene thermoplastic films, or mixed materials such as a film-coated nonwoven material. Preferably, the backsheet is a thermoplastic film having a thickness of from about 0.012 mm to about 0.051 mm. Particularly preferred materials for the backsheet include blown films 448220 and cast films RR5475 as manufactured by Tredegar Industries, Inc. of Terre Haute, IN. The backsheet 26 is preferably embossed and / or dull finished to provide a more fabric-like appearance. In addition, the backsheet 26 can allow the vapors to escape from the absorbent core 28 (i.e., breathable), while still preventing the exudates from passing through the backsheet 26. The topsheet 24 is placed adjacent to the surface of body of the absorbent core 28, and is preferably attached to the backsheet 26 by attachment means (not shown) such as those well known in the art. For example, the topsheet 26 can be secured to the backsheet 26 by a continuous uniform adhesive layer, a patterned adhesive layer, or an array of separate lines, spirals or dots of adhesives. The adhesives that have been found to be satisfactory are manufactured by H.B. Fuller Company of St. Paul, MN and marketed as HL-1258 and by Findley Adhesives Wauwatosa, VVI as H2031. The joining means will preferably comprise a network of open pattern filaments of adhesive, as disclosed in U.S. Patent 4,573,986, which was issued to Minetola et al. On March 4, 1986, the disclosure of which patent is incorporated in the present by reference. Alternatively, the joining means may comprise heat bonds, pressure joints, ultrasonic bonds, mechanical-dynamic joints or any other means of joining or combining these appropriate joining means as are known in the art. As used herein, the term "attached" encompasses configurations with which one element is directly secured to the other element by attaching the element directly to the other element, configurations with which the element is indirectly secured to the other element by fixing the member element or intermediate members which in turn are fixed to another element, and configurations with which the elements are kept in a forced position near the other element without being directly or indirectly insured to the other element. In a preferred embodiment of the present invention, the upper sheet 24 and the rear sheet 26 are joined together at the periphery 50 of the containment assembly 22 by the joining means not shown and the absorbent core 28 is stopped between them. That is, the absorbent core 28 is allowed to "float" between the topsheet 24 and the backsheet 26. The topsheet 24 is docile, of soft feel and non-irritating to the wearer's skin. In addition, the topsheet 24 is permeable to liquid allowing aqueous body fluids (eg, urine) to easily penetrate through its thickness. An appropriate top sheet can be manufactured from a wide variety of materials, such as porous foams, cross-linked foams, plastic films with aperture; woven or non-woven webs of natural fibers (e.g., cotton or wood fibers), synthetic fibers (e.g., polyester or polypropylene fibers) or a combination of natural and synthetic fibers. Preferably, the topsheet 24 is made of a substantially hydrophobic material to isolate the wearer's skin from the liquids contained in the absorbent core 28. There are a number of manufacturing techniques that can be used to manufacture the topsheet 24. For example , the upper sheet 24 may be a non-woven web of spunbonded, carded, wet-laid, melt-blown, hydroentangling fibers, combinations of the above, or 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 a short length polypropylene fiber web as manufactured by Veratec, Inc., a division of International Paper Company of Walpole, MA under the designation P-8. The diaper 20 preferably further comprises elasticized leg folds 32 to provide improved containment of liquids and other body exudates. Each elasticized leg fold 32 may comprise several different modalities to reduce leakage of body exudates in the leg regions (the leg fold may be and is sometimes also referred to as leg bands, side flaps, barrier folds, or elastic folds). The aforementioned US Patent 3,860,003 discloses a disposable diaper that provides a collapsible pouch opening having a side flap and one or more elastic members to provide an elasticized leg fold (gusset fold). U.S. Patent 4,909,803 issued to Aziz et al. On March 20, 1990, discloses a disposable diaper having "upright" elasticated fins (barrier folds to improve containment of the leg regions). U.S. Patent 4,695,278 issued to Lawson on September 22, 1987, discloses a disposable diaper having double folds including a gusset fold and a barrier fold. Although each leg elasticated fold 32 can be configured to be similar to any of the leg bands, side flaps, barrier folds, or elastic folds described above, it is preferred that the elasticized leg folds 32 comprise the extended double folds described in FIG. the TCP patent application commonly assigned to no. W0 94/18927 published September 1, 1994, the disclosure of which is incorporated herein by reference. The diaper 20 may further comprise an elastic waist feature 34 that provides improved fit and containment. The elastic waist feature 34 is that portion or area of the diaper 20 that is intended to expand and contract elastically to dynamically adjust to the wearer's waist. In the preferred embodiment of the present invention shown in Figure 1, the elastic waist feature 34 extends longitudinally inwardly of, and generally forms a portion of, the extreme edge of the diaper 56 located in the second waist region 44 toward the second waist edge 58b of the absorbent core 28 located in the second waist region 44. Although the elastic waist feature or any of its constituent elements may comprise a separate element secured to the diaper 20, the elastic waist feature 34 is preferably constructed with an extension of other diaper elements such as the back sheet 26 or the top sheet 24, preferably both the back sheet 26 and the top sheet 24. The elastic waist feature 34, can be constructed in a number of different configurations including those described in United States patents 4,515,595 and 5,151,092; previously referred; the disclosure of each of these references is incorporated herein by reference. The diaper 20 also comprises a fastening system 36 that forms a side closure, which maintains the first waist region 42 and the second waist region 44 in an overlapping configuration such that lateral stresses are maintained around the circumference of the diaper for keep the diaper on the user. Illustrative fastener systems are described in U.S. Patent 4,846,815 issued to Scripps on July 11, 1989; U.S. Patent 4,894,060 issued to Nestegardf on January 16, 1990; U.S. Patent 4,946,527 issued to Battrell on August 7, 1990; U.S. Patent 3,848,594 issued to Buell on November 19, 1974, and U.S. Patent B1 4,662,875 issued to Hirotsu et al. on May 5, 1997; the disclosure of each have been incorporated herein by reference. Any of the aforementioned fastener systems would be appropriate for the diaper 20 of the present invention. The preferred embodiment of the fastening system 36 must further provide that band of lateral tension around the circumference of the diaper which must pass through the support waist feature 38. Such preferred fastening systems 36 may comprise either tape means or fastening means. mechanics For example, a suitable fastener system 36 may comprise a tape tab, a release portion for protecting the adhesive on the tape tab, and a landing zone wherein the tape tab is located in one of the first or second regions of tape. waist 42 or 44, preferably in the second waist region 44, adjacent an end edge 56 in the waist region and the landing zone is located in the other of the waist regions 42 or 44, preferably in the first region of waist 42, adjacent the end edge 56 in the waist region. The diaper 20 shown in Figure 1, preferably also comprises side panels 30 in the first waist region 42 and side panels 40 in the second waist region 44. These side panels 30 and 40 can be formed from extensions of the top sheet 24 or back sheet 26, or both. Preferably, the side panels 30 and 40 comprise discrete members that are attached to and extend laterally outwardly from each longitudinal edge 52 of the containment assembly 22, in at least the waist regions 42 and 44 respectively. The portions of the panels 30 and 40 may further be attached to and extend laterally outward from each longitudinal edge 52 of the containment assembly 22 in the crotch region 46. The side panels 30 and 40 may be attached to the containment assembly by any means familiar to the technique. For example, the side panels 30 and 40 may be attached to the containment assembly 22 by a continuous, uniform adhesive layer, a patterned adhesive layer, or an array of separate lines, spirals or dots of adhesives. The adhesives that have been found to be satisfactory are manufactured by H.B. Fuller Company of St. Paul, Minnesota and marketed as HL-1258. The joining means will preferably comprise a network of open-pattern filaments of adhesive as described in U.S. Patent 4,573,986, which was issued to Minetola et al. On March 4, 1986, more preferably several lines of adhesive filaments twisted in a spiral pattern as illustrated by the apparatus and method shown in U.S. Patent No. 3,911,173 issued to Sprague; Jr. on October 7, 1975; U.S. Patent 4,785,996, issued to Ziecker et al. on November 22, 1978; and United States Patent 4, 842, 666, issued to Werenicz on June 27, 1989. The disclosure of 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 are known in the art. The side panels 30 and 40 can be made from any of the materials familiar in the art. For example, the side panels 30 and 40 can be made from flexible, thin plastic films, porous foams, woven or non-woven webs of natural or synthetic fibers. The side panels 30 and 40 can also be made from laminar units combining said materials. A particularly preferred material for the side panels 30 and 40 comprises a laminar unit of a nonwoven web of short length polypropylene fibers as manufactured by Veratec, Inc., a division of International Paper Company of Walpole MA, under the designation P-8 with a thin thermoplastic film such as blown film RR8220 and cast film 445475 as manufactured by Tredegar Industries, In. of Terre Haute, IN. In an even more preferred embodiment of the present invention, the side panels 30 in the first waist region 42 or, preferably, the side panels 40 in the second waist region 44 are elastified. The elasticized panels provide an elastically extensible feature that provides greater comfort and contour adjustment by initially comfortably fitting the diaper to the wearer and holding this adjustment throughout the time of use to the point where the diaper has been loaded with exudates, since the elasticized panels allow the diaper sides to expand and contract. The elasticized panels further provide effective further application of the diaper 20, since even if the person attaches one elastified panel farther than the other during the application (asymmetric application), the diaper 20 will "self-adjust" during use. Although the diaper 20 of this preferred embodiment of the present invention preferably has the elastified panels operatively associated with the side panels 40, which are disposed in the second waist region 44, the diaper 20, alternatively, may be provided. with elasticized side panels disposed in the first waist region 42 or both of the first waist region 42 and the second waist region 44. Although the panels can be constructed in a number of configurations, examples of diapers with elasticized panels placed in the ears (ear flaps) of the diaper are disclosed in U.S. Patent 4,857,067 issued to Wood et al. on August 15, 1989; U.S. Patent 4,381,781 issued to Sciaraffa et al. on May 3, 1983; U.S. Patent 4,938,753 issued to Van Gompel et al. on July 3, 1990; U.S. Patent 5,358,500 issued to La Von et al. on October 25, 1994; and the aforementioned United States Patent 5,151,092; the disclosure of each one being incorporated herein by reference. For example, the elasticized panels may comprise a laminar unit of a nonwoven web, an elastic member and a flexible, thin thermoplastic film.

Suitable materials for the non-woven web and thin, flexible thermoplastic film have been described above with respect to the topsheet 24 and backsheet 26 respectively. A suitable material for the elastic member is manufactured by Exxon Chemical Company, Lake Zurich, IL under the designation EXX 550. Such laminar units can then be subjected to sufficient mechanical stretching to permanently lengthen the non-woven web and the thermoplastic film using a process such as that described in the aforementioned U.S. patent 5,151,092 to form the elasticized panel. Alternatively, the non-elastic portions of the side panels can be joined or picked up before being combined with the elastic member. The preferred elastified panels comprise a film frame in the form of a structural elastic (SELF). The film web in structural elastic form is an extensible material exhibiting a behavior similar to elastic in the direction of elongation without the use of additional elastic materials. The SELF frame includes a stretchable work network that has at least two contiguous, distinct and different regions.

One of the regions is configured in such a way that it will exhibit resistance forces in response to an axial elongation applied in a direction parallel to the predetermined axis before a substantial portion of the other region that develops significant resistance forces to the applied elongation. At least one of the regions has a surface path length that is greater than that of the other region as measured substantially parallel to the predetermined axis while the material is in an unstressed condition. The region exhibiting the greatest surface path length includes one or more deformations that extends beyond the plane of the other region. The SELF screen exhibits at least two significantly different stages of resistance strength controlled to elongation along at least one predetermined axis, when subjected to an elongation applied in a direction parallel to the predetermined axis. The SELF weave exhibits first strengths of applied elongation until the elongation of the weft is sufficient to cause a substantial portion of the region having the greatest length of surface path between the plane of elongation applied, after which the SELF screen exhibits second strengths of additional elongation resistance. The forces of total resistance to elongation are greater than the first strengths of resistance to elongation provided by the first region. The SELF frames suitable for the present invention are more fully described in the commonly assigned copending United States patent application No.

Series 08 / 203,456 filed by Donald C. Roe et al. On February 24, 1994, the disclosure of which is incorporated herein by reference. As also shown in Figure 2, the diaper 20 further comprises a waist shield or shield 37. The waist protection 37 is provided for the purpose of preventing leakage of the aqueous body fluids from the supporting waist feature. 38 (described below), through the top sheet 24. In the preferred embodiment of the present invention shown in Figures 1 and 2, the waist protection is secured to the top sheet 24 in the waist region 42 of the diaper 20 In the most general case, a waist protection 37 would be secured to the top sheet 24 in any waist region of the diaper 20 that also contains a support waist feature 38. The waist shield or shield 37 extends longitudinally outwardly. from slightly below the waist edge 58a of the absorbent core 28, where it partially covers a transverse end of the acquisition component 27 of the absorbent core 28 to the extreme edge of the diaper 56 located in the first waist region 42. The protections or shields of waist of this type are discussed in greater detail in the patent of the United U.S. 4,578,071, issued to Kenneth B. Buell on March 25, 1986, the disclosure of which is incorporated herein by reference. The protection or waist shield 37 is impermeable to aqueous body fluids. This is preferably manufactured from a thin plastic film although other flexible liquid-impermeable materials can be used. The shield or waist shield 37 can thus be comprised of materials with the same properties essentially as are suitable for the backsheet 26. A preferred material for the waist shield protection 37 is a thermoplastic film having a thickness of about 0.012 mm at approximately 0.051 mm. The diaper 20 still further comprises a support waist feature 38.

As used herein, the term "supporting waist feature" means a component of the diaper 20, located at the first waist region 42 or at the second waist region 44 or at both waist regions that resist loss. Adjustment or premature waist leakage due to at least one of the failure modes described above. In the preferred embodiment of the present invention the diaper 20 shown in Figures 1 and 2, the supporting waist feature 38 is shown as an extension of a portion of the absorbent core 28 in the first waist region 42 of the diaper 20. Very preferably, the support waist feature 38 extends longitudinally from the first waist edge 58a of the absorbent core 28 towards an adjacent transverse end 56 positioned longitudinally in the first waist region 42 of the diaper 20. Alternatively, a diaper of the present invention could have a supporting waist feature located in the second waist region 44 or both waist regions 42 and 44. At a minimum, the waist support feature 38 should extend longitudinally from an end edge 58a, 58b core 28 towards the first or second waist regions 42 or 44, and through the tension band provided in med waist regions In addition, the support waist feature of the present invention is intended to comprise extensions of the absorbent core 28 or one or more separate elements that are in effective fluid communication with the absorbent core 28 or both. As illustrated in Figure 2, the preferred support waist feature 38 comprises at least one layer of a material, preferably an absorbent foam having the physical properties as described in U.S. Patent 5,268,224. In the embodiment shown in Figure 2, the support waist feature 38 comprises 3 layers of this foam 39a-39c. These layers 39a-39c are not, typically joined together by adhesive but are simply extensions of the fluid redistribution component 29 and, therefore, are in effective fluid communication with each other and with the fluid acquisition component 27. Supportive waist feature 38 must have physical or chemical properties that counteract at least part of the negative effects of the various response modes for loss of fit or premature leakage at the waist due to bulging, slippage or rolling as it is exhibited by the diapers of the technique it acts. In its simplest form, for example, a diaper comprising only an upper sheet 24, a back sheet 26, a core 28, elasticized leg cuffs 32, a means for creating lateral tension in the waist region, such as a system bra 36, and a support waist feature 38, the support waist feature 38 would provide improved fit and containment when comparing an absorbent article having a similar construction with an elastic waistband of the current technique in place of the waist feature 38. An advantage of the absorbent articles of the present invention is that they provide resistance to loss of fit and containment due to rolling, slip / detachment or cupping / bulging. When absorbent articles are used, the loss of stiffness in the waist area, particularly due to repeated application of the forces encountered during normal use, may cause the core materials to fall away from the waist regions of the waist. absorbent article and towards the crotch regions in such a way that the contribution of the core materials that provide rigidity in the waist regions are substantially eliminated. Specifically, the support waist feature 38, provides an improved rigidity component, which provides a resistance to bending or bending, even after repeated applications of forces encountered during normal use which tend to cause winding, slip / loosening or bulging / cupping, counteracting these forces. Without such a stiffening component, the expansion of the stomach can push on the waist of the upper part of the absorbent article causing it to roll up and move downward. For example, one measure of this stiffening component is the cantilever bending value. It has been found that a support waist feature 38 with a dry cantilever bending value of more than about 8.3 cm, preferably greater than about 9.4 cm will provide a satisfactory strength of resistance that counteracts bending when the absorbent article is dry or partially damp. Importantly, as the support waist feature 38 becomes saturated with the aqueous body fluids, that is, when the risk of waist leakage is greater, the support waist feature 38 at least maintains a strength of resistance to winding equal to the strength of resistance when the diaper 20 is dry. This resistance to rolling when wet is shown by the cantilever bending values increasing to more than about 9.9 cm, preferably to more than about more than 10.7 cm, most preferably to more than about 11.6 cm when a waist feature is saturated 38 of the present invention with aqueous, synthetic body fluids. A method for measuring saturated and dry cantilever bending values is provided in the test methods section below. These changes in stiffness when moistened with aqueous body fluids can be clearly seen if defined in terms of a cantilever bending relationship. As used herein, the term "cantilever bending ratio" is defined as the ratio of the cantilever bending value when the absorbent article is saturated with synthetic aqueous body fluids to the cantilever bending value when the absorbent article is dry. The absorbent articles of the present invention have been found to have a cantilever bending ratio of about 1.0: 1 or greater. Absorbent articles of the present invention having this minimum cantilever bending ratio will at least maintain their dry stiffness in the waist regions when saturated with synthetic aqueous body fluids. Preferably, the cantilever bending ratio for an absorbent article of the present invention is greater than 1.1: 1 and most preferably greater than 1. 3: 1 That is, preferred embodiments of an absorbent article of the present invention increase in stiffness when saturated with synthetic aqueous body fluids. In addition, the resistance to bending is maintained even when the supporting waist feature 38 has been rubbed many times. For example, the dry cantilever bending value after the supporting waist feature 38 has been cyclically flexed is at least about 8.0 cm. Repeating this test when the support feature 38 is saturated with synthetic aqueous body fluids results in a cantilever bending value of at least about 9.6 cm, preferably greater than about 11.1 cm. A method to determine the retention of stiffness in cyclical flexions is given in the test methods section below. The stiffness retention ratio can also be defined. As used herein, the term "rigidity retention ratio" is defined as the ratio of the cantilever bending values measured on the same sample before and after the sample has been cyclically flexed for 20 cycles (see section of METHODS TEST). The stiffness retention ratio can be calculated for any of the dry samples or for samples that have been saturated with synthetic aqueous body fluids. The supporting waist features of the present invention have a stiffness retention ratio of at least about 0.90 when dry, preferably greater than about 0.95. When the sample is saturated with synthetic aqueous body fluids the stiffness retention ratio is at least about 0.88, preferably greater than about 0.92. The support waist feature 38 of the present invention and the absorbent core 28 can also cooperate to provide a strength of resistance which helps to avoid even simple absorbent articles without elastifying waist features or side panels described above that move downwardly due to either the normal movement of the body or the downward force created when the absorbent article is loaded with body exudates. It is shown in Figures 3 and 4 of this cooperation, which shows a baby user of a diaper embodiment of the present invention. As can be seen in these figures, the minimum circumference 85 around a baby is along a line surrounding the baby user, which connects at a point slightly below the belly, in the crease of the belly, and a point about the narrow part of the back. The lateral tension band provided, for example, by a fastening system 36, is said to move downwardly if the waistband of a diaper moves from where it is applied 80 (typically around the waist of a wearer at or near the navel of the wearer). user and above the crease of the belly), to cover this minimum circumference line 85. The tension band is predisposed to move towards the minimum circumference line 85 because the tension will be reduced as this is done. When the supporting waist feature 38 is an extension of or unitary with the absorbent core 28, as in the preferred embodiment of the invention shown in Figures 1 and 2, the two components of the diaper cooperate to dissipate those forces F1t due to movement. normal of the user or to carry body exudates, which would otherwise serve to cause the diaper to move downward by providing a resistance force F2 on the user's legs. That is, the support waist feature 38 and the absorbent core 28 function as an "entrepuntal" that transfers such forces from the waist regions of a diaper to the legs of the wearer. This cooperation is illustrated in Figure 4. The loss of mechanical integrity when the core components of the absorbent articles of the current art become saturated with aqueous body fluids prevents such cooperation therein. further, when an absorbent article is provided with elasticized portions to help provide lateral tension and the waist regions of the diaper 20, such as the elasticized side panels 40 of the preferred embodiment of the present invention shown in Figure 1, the waist feature of support 38 provides the additional benefit of compensating stress relaxation in the polymeric systems used as elastic members in said elasticized portions. As discussed in more detail below, the caliber of the supporting waist feature 38 increases as it becomes saturated with the aqueous body fluids. This gauge grows increasing the overall circumference of the absorbent article in the waist and thus lengthens the elasticized portions in the waist region of the absorbent article compensating the relaxation of the tension with the increased contractive force caused by the elongation of the elasticized portions. Figure 5 shows a diagrammatic representation of the contractive force changes within the tension band in the waist region of the preferred embodiment of the present invention, diaper 20. When the diaper 20 is applied to a wearer, the contractive forces they are determined by the amount of stretching provided to the elastic elements in the waist region during application, which forms the tension band. This is shown in the first portion of Figure 5 when the contractive force goes from essentially zero to a maximum over a very short time (i.e., during the application of the elastic elements that are stretched rapidly for a given elongation and the elongation is then fixed by the fastener system). Over time, the contractive forces at the waist decrease substantially due to the relaxation of tension. These reduced contractive forces can contribute to the cupping in the waist region of the diaper with the loss resulting from the adjustment and the increased risk of waist leakage due to contractive forces being reduced within the tension band. However, for an absorbent article of the present invention, the support waist feature 38 compensates for this loss of contractive force due to stress relaxation. This compensation for the loss of contractive force due to the relaxation of tension is shown in the second portion of Figure 5, by the second increase in contractive force over a very short period of time. The support waist feature 38 equals the tension relaxation by effectively increasing the degree of stretch of the elastic elements within the tension band around the circumference of the absorbent article. The support waist feature 38 is equal to the relaxation of tension increasing in caliber as the aqueous body fluids are exposed. Since the only direction to which the waist support characteristic in gauge can increase when exposed to (i.e., wetted with aqueous body fluids) is away from the user (i.e., a user's waist is not bound by the increase of the caliber), the effective diameter of the user's waist is increased by the amount of caliber that grows and by any lateral expansion that may occur. This causes the circumference of the absorbent article to increase effectively around the user's waist, which results in additional stretching of the elastic elements. Mathematically, this growth can be established as: gauge growth by the support waist feature 38 an amount X mm averaged around the total length of the tension band results in the stretching of the elastic elements of the absorbent article by approximately 2_X mm additional. For example, the growth of caliber approximately 1 mm (-0.04 inches) results in the stretch of the elastic elements of approximately 6 mm. This resulting increase in the contractive forces within the tension band will depend on the specific stress / strain properties of the polymer system used as the elastic member. To ensure that the support waist feature 38 of the present invention equals a significant portion of the loss of contractive force due to stress relaxation, a supporting waist feature of the present invention has a caliber growth ratio of at least greater than 3.0: 1, preferably greater than 5.0: 1 and most preferably greater than 7.0: 1. As used herein, the term "caliber growth ratio" is intended to mean the caliber relationship of the supporting waist feature 38 when it is fully saturated with synthetic aqueous coforal liquids, (i.e., in its fully expanded) to the caliber of the supporting waist feature when it is in its dry state (ie, in its fully contracted state). For example, in its most preferred embodiment the support waist feature of the present invention has a dry gauge of approximately 1.5mm and a wet gauge of 13.8mm resulting in a caliber growth ratio of 9.2: 1. The methods for measuring the caliber in its fully expanded state (wet caliper) and the fully contracted state (dry caliper) are given in the TEST METHODS section below. The supporting waist feature of the present invention should also equalize the reduced lateral tension in the waist region due to different causes of stress relaxation in the elastic elements discussed therein. Examples of other causes of reduced lateral tension in the waist region include the stretching of the non-elastic elements at the waist and the sliding of the fastening system 36. In such cases, the effective circumference of the diaper 20 around the wearer's waist is increased. and the lateral tension in the waist regions decreases. By increasing the caliper as it becomes saturated with aqueous body fluids as described above, the supporting waist feature 28 of the present invention provides a sample against the wearer's waist which results in a strap tension in the waist region of the diaper 20 again tapering the diaper around the user's waist and equalizing the loss of lateral tension. A support waist feature 38 of the present invention should not only be able to grow in caliber as it becomes saturated with aqueous coforal liquids as discussed above, the support waist feature 38 may be able to grow in caliber when it is subjected to forces of use, such as compression forces within the tension band. That is, the expansive force caused by the growth of the caliber of the supporting waist feature 38 must be greater than the compressive forces in the tension band such that the supporting waist feature 38 can equalize the relaxation of the tension. A measure of this ability to resist compression forces and compression deflection resistance. The resistance to compression deflection can be quantified for purposes of this invention by measuring the amount of stress (% reduction in caliper) produced in a foam sample, which has been saturated and completely expanded with synthetic urine, which after A tension in the form of a confining pressure of 5.4 kPa has been applied to the sample. Preferred embodiments of the support waist feature 38 of the present invention have a resistance to compression deflection of less than about 40%. The method for measuring resistance to compression deflection is discussed briefly in the section on TEST METHODS 3A below, and more fully in the aforementioned U.S. Patent Application 07 / 989,270. Although the physical properties of the support waist feature 38 discussed above can be provided by absorbent foam materials, such as HIPE foams, this is preferred by at least a portion of the absorbent core 28 of the present invention., nothing said herein is intended to limit the present invention to only these materials. It is contemplated that the support waist features 38 of the present invention may comprise any of the materials or combinations of materials that possess either an increase in caliper upon wetting (i.e., a caliber growth ratio of at least 3.0: 1). ) a cantilever bending value in dry, and a cantilever wet bending value as described above (i.e., a cantilever bending ratio of at least 1.0: 1), or both. For example, the support waist feature 38 may comprise two elements one a stiffening element that provides a resistance of flexural strength and the other an element that provides compensation for the relaxation of the tension of the elastic elements of the absorbent article. The radiation-crosslinked polyethylene foams sold by Voltek, Inc., of Lawrence, MA under the Volara trademark are appropriate stiffening elements. Inflatable separators, similar to those described in U.S. Patent 5,330,459 issued to La Von, and others on July 19, 1994, the disclosure of which is incorporated by reference, may provide the gauge increase upon wetting to compensate the relaxation of tension in the elastic elements. For example, the inflatable spacers described herein preferably increase to a thickness of at least 10 times their thickness without inflating, most preferably at least 50 times their thickness without inflating (column 6, lines 64 to 68). Also modalities with waist characteristics that only provide rigidity or only an increase in caliber are contemplated. The diaper 20 is preferably applied to a user by placing one of the waist regions, preferably the second waist region 44, under the user's back and pulling the rest of the diaper between the user's legs, such that the other region preferably the first waist region 42 is placed across the front of the user. The tape tab of the fastener system 36 is then detached from the release portion of the fastener system. The person who places the diaper, then attaches one of the tape tabs to its corresponding landing area and then grabs the rest of the tape tab, pulls it and attaches it to its landing zone. Typically, the elastified side panels will be extended and tensioned during this operation to conform to the size and shape of the user. In an alternate embodiment of the present invention, useful as a training pant or a climbing diaper, the portions of the longitudinal edges 54 of the diaper 20 that lie in the waist regions 42 and 44, extend laterally outwardly from the portion. of the longitudinal edges 54 which are located in the crotch region 46. That is, for this alternate embodiment, the diaper is wider in the waist regions 42 and 44 than in the crotch region 46. In addition, the longitudinal edges 54 and the waist regions 42 and 44 are joined. That is, in this alternate embodiment of the present invention, the absorbent article is not provided with a fastening system. A side tension band is still provided to the waist regions of this alternate embodiment of this invention by the elasticized portions, such as the elasticized side panels. That is, the diaper 20 is folded around its transverse center line 102 such that the first waist region 42 is opposite the second waist region 44. The opposite longitudinal edges 54 of the diaper 20 in the first and second regions of waist (42 and 44 respectively) are then joined by familiar means to the technique to form seams. Depending on the transverse width of the first waist region 42 relative to the second waist region 44, these seams can be placed on the front., the side, or even on the back of this alternate modality of the absorbent article as it is being used. Examples of means for joining the edges to form seams are given in U.S. Patent 5,236,430 issued to Bridges on August 17, 1993, the disclosure of which is incorporated herein by reference.

TEST METHODS In describing the present invention, a number of features were established. When reported, these characteristics can be determined using the following test fluids and test methods. 1) Test Fluid - Synthetic Urine Several of the measurements described in the tests herein involve the use of a test fluid such as synthetic urine, ethanol, or 2-propanol (isopropyl alcohol). The synthetic urine used in a number of the tests described hereinafter is made from a commercially available synthetic urine preparation manufactured by Jayco Pharmaceuticals (Mechanicsburg, PA, 17055). This Jayco synthetic urine made from the preparation comprises KC1, 02%; Na2SO4, 0.2%; N | -? Pp, 0.085% (NH4) 2HP04; 0.015%, CaC12 * 2H20, 0.025% and MgC * 6 ^ 0, 0.05%. The synthetic urine samples were prepared according to the instructions on the label using distilled water. To aid dissolution, the Jayco salt mixture is added slowly to the water, the filtered sample if necessary to remove any particles. Any unused synthetic urine is discarded after a week. To improve the visibility of the fluid, you can add 5 drops of food blue color per liter of synthetic urine solution. The Jayco synthetic urine used has a surface tension of 65 + 5 dines / cm. 2) Free Absorbent Capacity The free absorbent capacity can be quantified for purposes of this invention by measuring the amount of synthetic urine absorbed by a sample of an absorbent material that has been saturated and expanded with synthetic urine. The samples and synthetic urine are equilibrated at a temperature of 31.1 ° C. The measurements are developed at room temperature. A test sheet in its collapsed state is expanded and saturated to its free absorbent capacity by soaking it in a Jayco synthetic urine bath. After 3 minutes, a cylinder having a circular surface area of 6.5 cm2 of the expanded sheet, saturated with a sharp circular die, is cut. The cylindrical sample is soaked in synthetic urine at 31.1 ° C for three additional minutes. The sample is then removed from the synthetic urine solution and placed on a digital scale. Any adjusted balance can be used with a weighting container that has an area larger than that of the sample and with a resolution of one milligram or less. Examples of such scales are the Mettler PM 480 and Mettler PC 440 (Mettler Instrument Corp, Hightstown NJ). After determining the weight of the wet sample (Ww), it is placed between two fine-mesh, plastic sieves, on top of four disposable paper towels. The sample is squeezed 3 times by firmly rolling a plastic roller over the upper sieve. The sample is then soaked, in distilled water for about 2 minutes, and squeezed between the mesh sieves as before.

This is placed between 8 layers of disposable paper towels (four on each side) and pressed with 20,000 pounds of force in a Carver laboratory press. The sample is then removed from the paper towels, dried in a Fisher convection oven at 180 ° F for 20 minutes, and its dry weight (Wd) recorded. The free absorbent capacity is the wet weight (Ww) minus the dry weight (Wd) divided by the dry weight (Wd): ((Ww-Wd) / Wd). The measurements to determine the free absorbent capacity of the sample can be made simultaneously with those to determine the resistance to compression deflection, and / or the expansion factor. 3) Specific area of surface per volume of foam The specific surface area per volume value of foam is derived from (the specific surface area of capillary suction that is measured during wetting of the dry foam structure, and (b) ) the density of the expanded foam structure after wetting to saturation, rather than by direct measurement of the collapsed, dry foam structure See copending United States patent application Serial No. 07 / 989,270 ( Dyer and others), presented on December 11, 1992, which is incorporated by reference, where the specific area by volume of foam is discussed in detail. 4) Capillary absorption pressures The isothermal curve of capillary absorption is generated using the vertical wicking absorbent capacity test described in the TEST METHODS section of the copending United States patent application Serial No. 07 / 989,270 (Dyer et al.), Filed December 11, 1992, which is incorporated by reference, except at 30 ° C instead of 3"C. The curve is a graph of the absorptive capacity of each segment as a function of the impregnation height by wicking effect The capillary absorption pressure is taken as the height of the foam having an absorbent capacity of half the free absorbent capacity of the foam.

) Cantilever bending value The cantilever bending value for the present invention is determined using method D 1388 ASTM standard test method for fabric stiffness: Cantilever test of option A. The following modifications to this test method must be made : 1) The samples are conditioned and the test is conducted at 88 ° C, 55% relative humidity. 2) The test samples comprise sections of the absorbent article instead of fabrics. 3) Bending stiffness is measured only in the longitudinal direction since this is the direction of bending that results in loss of fit. 4) All the samples are tested in such a way that they bend towards the outer surface 64 since this is the direction of flexion when a diaper is retracted. 5) Samples are tested in both the dry state and when they are saturated. 6) The Cantilever bending value equal to the length of the projection as defined in method D 1388 ASTM. 6) Retention of the stiffness in cyclical flexions The retention of the rigidity on flexion is determined from the data generated using the cantilever bending value test described above. Specifically: a) The initial cantilever bending value of the sample tested is determined as described above. b) The test sample is then flexed cyclically by orienting the sample in such a way that the long edges are aligned vertically, flexing it at an angle of 70 degrees in relation to the vertical alignment in a first direction, returning it to an angle of 0 degrees in relationship to the vertical alignment, and bending it at an angle of 70 degrees in relation to the vertical alignment in the opposite direction. A flexion cycle is defined as a bend at an angle of 70 degrees in each direction and a return to 0 degrees. c) The bending cycle is repeated 10 times at a speed of 10 bending cycles per minute. d) The cantilever bend value for the flexed sample is measured as described above. e) A relationship of stiffness retention for the sample can be calculated by dividing the measured cantilever bending value after the sample has been cyclically flexed by the initial cantilever bending value measured before bending. 7) Wet and dry gauge Calibration or thickness measurements for purposes of the present invention should be made when the sample is under a confining pressure of 350 Pa. A sample is provided for caliper measurement. A cylinder having a circular surface area of 6.5 cm2 is removed from the sample using a circular, sharp punch. An appropriate sundial type meter is placed on the sample to make gauge measurements. Any meter fitted with a foot having a circular surface area of at least 6.5 cm2 and capable of measuring gauge dimensions to 0.025 mm can be used. Examples of such meters are an Ames model 482 (Ames Co., Waltham, MA) or an Ono -Sokki model EG-225 (Ono -Sokki Co., Ltd., Japan). Gauge measurements are taken from 3 separate samples. Each sample is then saturated to its free absorbent capacity with Jayco synthetic urine. After two minutes, the caliber of each fully expanded, saturated sample is measured again. 8) Resistance to compression deflection Resistance to compression deflection can be quantified for purposes of this invention by measuring the amounts of stress (% reduction in caliber) produced in a sample, which has been saturated and completely expanded with urine synthetic, after a stress or strain in the form of a confining pressure of 5.1 kPa has been applied to the sample. In essence, the difference between the gauge measured under a lower confining pressure (0.05 psi (350 Pa)) and the gauge measured at 5.1 kPa defines the stress caused by the higher confining pressure. This method is described more fully in the TEST METHODS section of the patent application of the United States, copending Serial No. 07 / 989,270. 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 can be made without departing from the spirit and scope of the invention. Therefore, it is intended to cover the appended claims all of said changes and modifications that are within the scope of this invention.

Claims (9)

1. - An absorbent article for fitting around the user's body, the absorbent article having longitudinal and lateral center lines, which respectively define a longitudinal and a lateral direction, longitudinal edges such as a crotch region, a first and second waist regions, absorbent article comprising: an absorbent core comprising at least one fluid redistribution component, which is capable of transporting aqueous body fluids from the crotch region to at least one of said waist regions; an outer cover attached to said absorbent core and having longitudinal sides and lateral ends defining the perimeter of said outer cover, preferably said outer cover, comprises a liquid impermeable back sheet and a liquid permeable upper sheet attached to said back sheet around said perimeter, said absorbent core being placed between said top sheet and said back sheet; means for creating lateral tension through at least a portion of said waist regions disposed in said waist regions, preferably said means for creating lateral tension comprise a fastening system; and said absorbent article being characterized in that said absorbent article further comprises a support waist feature to reduce the loss of fit for said absorbent article that is placed in at least one of said waist regions, preferably in both of said regions. of waist, said supporting waist feature being in effective fluid communication with said absorbent core, preferably, said supporting waist feature is an extension of said fluid redistribution component of said absorbent core.

2. An absorbent article according to claim 1, wherein said supporting waist feature has a caliber growth ratio of at least 3.0: 1, preferably said caliper growth ratio is at least 5.0: 1. , most preferably said gauge growth ratio is at least 7.0: 1.

3. An absorbent article according to claim 1 or 2, wherein said supporting waist feature has a cantilever bending ratio of at least 1.0: 1 preferably said cantilever bending ratio is at least 1.1: 1 , more preferably said cantilever bending ratio is at least 1.3: 1.

4. An absorbent article according to claim 1, 2 or 3 wherein said supporting waist feature has a stiffness retention value of at least 0.9: 1 when dry, preferably said stiffness ratio is of at least 0.95: 1.

5. An absorbent article according to any of the preceding claims, wherein said absorbent article further comprises: at least a pair of side panels extending laterally placed at least partially one of said waist regions, wherein each of said side panels is attached to and extends laterally outward from one of said longitudinal sides of said outer cover, preferably said side panels are placed in drums of said first and second waist regions, more preferably said side panels in the second region. of waist are elastified and longitudinally extending elasticated leg cuffs associated in a connective manner with said longitudinal sides of said outer cover, preferably said elasticized leg cuffs comprise double extended folds.

6. An absorbent article according to any of the preceding claims, wherein said absorbent article further comprises: a protection or waist shield placed between said supporting waist feature and said upper sheet; and an elasticized waist feature extending longitudinally inwardly from said lateral end of said outer cover that is in said second waist region toward said absorbent core, preferably said elasticized waist feature comprises at least a portion of said top sheet and said back sheet.

7. An absorbent article according to any of the preceding claims, wherein said support waist feature comprises an absorbent foam, preferably said absorbent foam comprises a HIPE foam.

8. An absorbent article according to any of the preceding claims, wherein said fastening system comprises a tape fastening system.

9. An absorbent article according to any of the preceding claims, wherein said fastening system comprises a mechanical fastening means.