WO2001001904A1

WO2001001904A1 - Disposable, absorbent, pull-on pants

Info

Publication number: WO2001001904A1
Application number: PCT/US1999/014905
Authority: WO
Inventors: Eduardo Gerardo Diaz Castillo; Craig Andrew Hawkins
Original assignee: The Procter & Gamble Company
Priority date: 1999-06-30
Filing date: 1999-06-30
Publication date: 2001-01-11
Also published as: PE20010077A1; AR020865A1; AU5086999A

Abstract

Disposable, absorbent, pull-on pants have a front region, a back region, and a crotch region between the front region and the back region. These pull-on pants include an absorbent chassis provided in the front region, the back region and the crotch region. The absorbent chassis has a front top edge and two opposing front side edges in the front region. Each front side edge has a front end point, and the front top edge is disposed between the front end points. An imaginary front straight line is defined by connecting the two front end points with a straight line. The front top edge has at least a portion which is below the imaginary front straight line. The front region is joined to the back region to form two leg openings and a waist opening.

Description

DISPOSABLE, ABSORBENT, PULL-ON PANTS

FIELD OF THE INVENTION The present invention relates to disposable, pull-on pants. Specifically, the present invention relates to disposable, absorbent, pull-on pants.

BACKGROUND OF THE INVENTION Infants and other incontinent individuals wear disposable garments such as diapers to receive and absorb urine and other body exudates. Disposable pull-on garments having fixed sides, which are also called "pants type" garments, have become popular for use on children able to walk and often who are toilet training, and with incontinent adults. These disposable, absorbent, pull-on pants have side panels with edges that are seamed together to form two leg openings and a waist opening. In order to contain body exudates as well as fit a wide variety of body shapes and sizes, these absorbent, pull-on pants need to fit snugly about the waist and legs of the wearer without drooping, sagging, or sliding down from its position on the torso.

However, a wearer's large or extended abdomen may cause absorbent pants such as pull-on diapers and/or adult incontinence pants to sag, and/or slip. For example, a baby's extended abdomen may force the front of their diaper lower during -use. This may cause the absorbent pants to leak, bunch up, and/or sag during use, especially when the baby repeatedly sits down and stands up. With tape-type absorbent pants, the tape may be adjustable, to take into account the wearer's extended abdomen. However, with absorbent, pull-on pants, the sides are fixed, and thus the front of the diaper may still sag.

Accordingly, the need exists for disposable, absorbent, pull-on pants which minimize or avoid these disadvantages and provide an in-use fit which is better tailored to a body with an extended abdomen. SUMMARY OF THE INVENTION

The present invention is directed to disposable, absorbent, pull-on pants having a front region, a back region, and a crotch region between the front region and the back region. The disposable, absorbent, pull-on pants include an absorbent chassis provided in the front region, the back region and the crotch region. The absorbent chassis has a front top edge and two opposing front side edges in the front region. Each front side edge has a front end point, and the front top edge is disposed between the front end points. An imaginary front straight line is defined by connecting the two front end points with a straight line. The front top edge has at least a portion which is below the imaginary front straight line. The front region is joined to the back region to form two leg openings and a waist opening.

It has now been found that disposable, absorbent, pull-on pants possessing a lowered front top edge may reduce or avoid in-use slippage and sagging caused by the wearer's extended abdomen. Furthermore, it has now been found that the present invention may fit more comfortably, reduce in-use leakage, and/or require less materials to produce.

These and other features, aspects, advantages, and variations of the present invention, and the embodiments described herein, will become evident to those skilled in the art from a reading of the present disclosure with the appended claims, and are covered within the scope of these claims.

BRIEF DESCRIPTION OF THE DRAWINGS While the specification concludes with claims particularly pointing out and distinctly claiming the invention, it is believed that the invention will be better understood from the following description of preferred embodiments which is taken in conjunction with the accompanying drawings in which:

Fig. 1 is a front perspective view of one preferred embodiment of the disposable, absorbent, pull-on pants of the present invention in a typical in-use configuration;

Fig. 2 is a partially cut-away plan view of the embodiment shown in Fig. 1 ; Fig. 3 is a cross-sectional view of a preferred embodiment taken along the section line 3-3 of Fig. 2;

Fig. 4 is a side view of a baby with an extended abdomen wearing an embodiment of the present invention; Fig. 5 is a simplified plan view of one preferred embodiment of the disposable, absorbent, pull-on pants of the present invention; and

Fig. 6 is a side view of a wearer showing a preferred angle of fit of the present invention.

DETAILED DESCRIPTION OF THE INVENTION All cited references are incorporated herein by reference in their entireties. Citation of any reference is not an admission regarding any determination as to its availability as prior art to the claimed invention. The drawings herein are not necessarily drawn to scale.

The term "absorbent" as used herein refers to absorbing and containing the various exudates discharged from the body.

The term "disposable" as used herein describes garments which are not intended to be laundered or otherwise restored or reused as a garment (i.e., they are intended to be discarded after a single use and, preferably, to be recycled, composted or otherwise disposed of in an environmentally-compatible manner).

The term "longitudinal" as used herein refers to a line, axis, or direction in the plane of the disposable, absorbent, pull-on pants that is generally aligned with (e.g. approximately parallel with) a vertical plane which bisects a standing wearer into left and right halves when the disposable, absorbent, pull-on pants are worn. Herein, "transverse" and "lateral" are interchangeable and refer to a line, axis or direction which lies within the plane of the disposable, absorbent, pull-on pants that is generally perpendicular to the longitudinal direction (which divides the wearer into front and back body halves). The term "pull-on pants" as used herein refers to articles of wear which have a defined waist opening and a pair of leg openings and which are pulled onto the body of the wearer by inserting the legs into the leg openings and pulling the article up towards the waist.

The term "uncontracted state" as used herein is used herein to describe the state of pull-on pants in their unseamed (i.e., seams are removed), flat, and relaxed condition, as if all elastic materials used are removed therefrom.

Referring to the drawings, Fig. 1 shows a front perspective view of one preferred embodiment of the disposable, absorbent, pull-on pants of the present invention in a typical in-use configuration. The disposable, absorbent, pull-on pants, 10, of the present invention have a front region, 12, a back region, 14, and a crotch region, 16, between the front region, 12, and the back region, 14. An absorbent chassis, 18, is provided in the front region, 12, the back region, 14, and the crotch region, 16. The absorbent chassis, 18, includes a topsheet, 20, and a backsheet, 22, associated with the topsheet, 20. During use, the topsheet, 20, is positioned adjacent to the wearer's body, while the backsheet, 22, is positioned away from the wearer's body.

In Fig. 1 , the absorbent chassis, 18, is sized and shaped to fit on the human body, for example, as a pull-on diaper, incontinence pants or briefs, training pants, feminine hygiene garments or panties, and the like. The topsheet, the backsheet, and optionally the absorbent core (Fig. 2 at 54) may be assembled in a variety of well known configurations; exemplary chassis configurations are described generally in U.S. Patent 3,860,003 entitled "Contractible Side Portions for Disposable Diaper" which issued to Buell on January 14, 1975; and U.S. Patent 5,151 ,092 entitled "Absorbent Article With Dynamic Elastic Waist Feature Having A Predisposed Resilient Flexural Hinge" which issued to Buell, et al., on September 29, 1992.

In Fig. 1 , the front region, 12, of the absorbent chassis, 18, has a front top edge, 24, and two opposing front side edges, 26, and 26'. Each front side edge, 26 and 26', has a front end point, 28 and 28', respectively. The front end point, 28, is the point of the front side edge, 26, which is closest to the waist opening (see 34, below). The front top edge, 24, is disposed between the front end point, 28, and the front end point 28'. When in the uncontracted state (i.e., Fig. 2), an imaginary front straight line, 30, is defined by connecting the front end point, 28, and the front end point, 28' with a straight line. In Fig. 1 , the imaginary front straight line, 30, follows the curvature of the pants when they are ready to be worn (see also Fig. 4); however, when Fig. 1 is viewed in conjunction with Fig. 2, it is seen that the imaginary front straight line, 30, remains straight, when the pants of the present invention are placed in the uncontracted state (i.e., the plan view of Fig. 2). Accordingly, the term "straight line" as used herein indicates a line which directly connects two points, e.g., the front end points, 28 and 28', when the present invention is placed in the uncontracted state. One skilled in the art will recognize, however, that when the present invention is ready to be worn or actually worn (see Fig. 1 and Fig. 4), such a "straight line" becomes a curved arc which follows the curvature of the body. In Fig. 1 , a portion of the top front edge, 24, is below the imaginary front straight line, 30. As used herein, the term "below" indicates that in the uncontracted state (e.g., Fig. 2), the referred-to portion is closer to the crotch region than the portion it is compared to, e.g., in Fig. 2, the front top edge, 24, is closer to the crotch region, 16, than the imaginary front straight line, 30. Conversely, the term "above" indicates that in an uncontracted state, as seen in Fig. 2, the referred-to portion is farther from the crotch region than the portion it is compared to. For example, in Fig. 2, the back top edge, 36, is farther away from the crotch region, 16, than the imaginary back straight line, 42. Thus, if the intended user is an infant, the lowest point of the front top edge, in the uncontracted state (see, e.g., Fig. 2), is preferably from about 5 mm to about 50 mm, more preferably from about 10 mm to about 30 mm, and even more preferably from about 15 mm to about 25 mm below the imaginary front straight line. If, however, the intended user is an adult, the lowest point of the front top edge, in the uncontracted state, is preferably from about 5 mm to about 75 mm, more preferably from about 10 mm to about 60 mm, and even more preferably from about 15 mm to about 45 mm below the imaginary front straight line.

The front top edge, 24, of Fig. 1 is depicted as a smooth curve, virtually all of which is below the imaginary front straight line, 30. Such a front top edge, 24, in which all, or substantially all of the front top edge is below the imaginary front straight line, 30, is highly preferred, as it is particularly suited to follow the curve of the abdomen. However, it is recognized that a front top edge having a different design and/or shape is also useful herein, as long as at least a portion of the front top edge is below the imaginary front straight line. Thus, the preferred front top edge useful herein includes a smooth curve-shaped front top edge, a "V-shaped" front top edge (see Fig. 5), a rectangle-shaped front top edge, and combinations thereof.

In Fig. 1 , the front region, 12, is joined to the back region, 14, so as to form two leg openings, 32, and a waist opening, 34. In the back region, 14, the absorbent chassis, 18, has a back top edge, 36, and two opposing back side edges, 38 and 38'. Each back side edge, 38 and 38', has a back end point, 40, and 40', respectively. The back end point, 40, is the point of the back side edge, 38, which is closest to the waist opening, 34. The back top edge, 36, is disposed between the back end point, 40, and the back end point, 40'. When in the uncontracted state (i.e., Fig. 2), an imaginary back straight line, 42, is defined by connecting the back end point, 40, and the back end point, 40', with a straight line. As with the imaginary front straight line, described above, one skilled in the art will understand that the imaginary back straight line, 42, in Fig. 1 is a curved arc which follows the curve of the body. However, in the plan view of Fig. 2, the imaginary back straight line is a straight line which directly connects the back end points, 40 and 40'. As shown in Fig. 1 , a portion of the back top edge, 36, is optionally above the imaginary back straight line, 42.

Thus, if the intended user is an infant, the highest point of the back top edge, in the uncontracted state (see, e.g., Fig. 2), is preferably from about 5 mm to about 50 mm, more preferably from about 10 mm to about 30 mm, and even more preferably from about 15 mm to about 25 mm above the imaginary back straight line. If, however, the intended user is an adult, the highest point of the back top edge, in the uncontracted state, is preferably from about 5 mm to about 75 mm, more preferably from about 10 mm to about 60 mm, and even more preferably from about 15 mm to about 45 mm above the imaginary back straight line.

However, as the front region, 12, and the back region, 14, of Fig. 1 are joined together, the front side edges, 26 and 26' substantially correspond to back side edges, 38 and 38'. Similarly, in Fig. 1 , the front end points, 28 and 28', substantially correspond to the back end points, 40 and 40'. In a preferred embodiment, the corresponding front side edge and back side edge are seamed directly or indirectly, to form a seam (Fig. 4 at 80). The seam may be formed in an overlapping manner to make an "overlapping seam." Alternatively, the front side edges may be seamed to the corresponding back side edge, in a "butt seam." The bonding of the seams may be performed by any suitable means known in the art appropriate for the specific materials employed. Thus, sonic sealing, heat sealing, pressure bonding, adhesive or cohesive bonding, sewing, autogeneous bonding, and the like may be appropriate techniques. Preferably, these seams are joined by a predetermined pattern of heat/pressure or ultrasonic welds which withstands the forces and stresses generated on the absorbent chassis, during wear.

The back top edge, 36, of Fig. 1 is depicted as a smooth curve, substantially all of which is above the imaginary back straight line, 42. Such a back top edge, 36, is highly preferred, as it may reduce BM leakage, and/or help stabilize the disposable, absorbent, pull-on pants, 10, on the body of the wearer. Such a back top edge, 36, is also highly preferred if it is complementary to the front top edge, 24. During the typical production process for the disposable, absorbent, pull-on pants of the present invention, the front top edge of a garment is typically abutting the back top edge of the next garment (or visa-versa). Therefore, where the back top edge is complementary to the front top edge, the cutting of the pull-on pants' pattern is significantly simplified and no material is wasted. This may therefore provide a significant savings in production and/or per-unit materials costs. However, it is recognized that a back top edge may possess a different design and/or shape as that of the front top edge. In an embodiment of the present invention, the back top edge is a straight line defined by the imaginary back straight line (see Fig. 5 at 36). Thus, the preferred back top edge useful herein includes a straight line, a smooth curve-shaped back top edge, a peaked or uneven back top edge, a rectangle-shaped back top edge, and combinations thereof.

Generally, the topsheet useful herein is preferably compliant, soft feeling, and non-irritating to the wearer's skin. Further, the topsheet is liquid pervious, in order to permit liquids (e.g., urine) to readily penetrate through its thickness. A suitable topsheet may be manufactured from a wide range of materials such as woven and nonwoven materials; polymeric materials such as apertured formed thermoplastic films, apertured plastic films, and hydroformed thermoplastic films; porous foams; reticulated foams; reticulated thermoplastic films; and thermoplastic scrims. Suitable woven and nonwoven materials may include natural fibers (e.g., wood or cotton fibers), synthetic fibers (e.g., polymeric fibers such as polyester, polypropylene, or polyethylene fibers), or a combination of natural and synthetic fibers. The topsheet is preferably made of a hydrophobic material, in order to isolate the wearer's skin from liquids which have passed through the topsheet (i.e., to prevent rewet). If the topsheet is made of a hydrophobic material, at least the upper surface of the topsheet is preferably treated to be hydrophilic so that liquids will transfer through the topsheet more rapidly. This diminishes the likelihood that body exudates will flow off the topsheet, rather than being drawn through the topsheet, and being absorbed by, for example, an absorbent core (See Fig. 2, at 54).

Furthermore, a topsheet (or topsheet material) may be rendered hydrophilic by treating it with a surfactant. Suitable methods for treating a topsheet with a surfactant include spraying the topsheet with the surfactant and immersing the topsheet into the surfactant. A more detailed discussion of such a treatment and hydrophilicity is contained in U.S. Patent No. 4,988,344 entitled "Absorbent Articles with Multiple Layer Absorbent Layers" issued to Reising, et al. on January 29, 1991 and U.S. Patent No. 4,988,345 entitled "Absorbent Articles with Rapid Acquiring Absorbent Cores" issued to Reising on January 29, 1991.

In a preferred embodiment, the topsheet is a nonwoven web that provides a reduced tendency for surface wetness, and consequently facilitates maintaining urine absorbed by the absorbent core (Fig. 2 at 54) away from the user's skin, after wetting. A preferred topsheet material is a thermobonded carded web which is available as Code No. P-8 from Fiberweb North America, Inc. (Simpsonville, South Carolina, U.S.A.). Another preferred topsheet material is available as Code No. S-2355 from Havix Co., Ltd. (Gifu, Japan). This material is a bi-layer composite material, and made of two kinds of synthetic surfactant treated bicomponent fibers by using carding and air-through technologies. Yet another preferred topsheet material is a thermobonded carded web which is available as Code No. Profleece Style 040018007 from Amoco Fabrics, Inc. (Gronau, Germany). Another preferred topsheet material includes an apertured formed film.

Apertured formed films are pervious to body exudates and yet non-absorbent, and have a reduced tendency to allow liquids to pass back through and rewet the wearer's skin. Thus, the surface of the formed film which is in contact with the body remains dry, thereby reducing body soiling and creating a more comfortable feel for the wearer. Suitable formed films are described in U.S. Patent No. 3,929,135, entitled "Absorptive Structures Having Tapered Capillaries", issued to Thompson on December 30, 1975; U.S. Patent No. 4,324,246 entitled "Disposable Absorbent Article Having A Stain Resistant Topsheet", issued to Mullane, et al. on April 13, 1982; U.S. Patent No. 4,342,314 entitled "Resilient Plastic Web Exhibiting Fiber-Like Properties", issued to Radel, et al. on August 3, 1982; U.S. Patent No. 4,463,045 entitled "Macroscopically Expanded Three- Dimensional Plastic Web Exhibiting Non-Glossy Visible Surface and Cloth-Like Tactile Impression", issued to Ahr, et al., on July 31 , 1984; and U.S. Patent No. 5,006,394 "Multilayer Polymeric Film" issued to Baird on April 9, 1991. In a preferred embodiment, the topsheet is compatible with other materials (e.g., component materials in the backsheet), in terms of its design/process, for forming ventilation holes (not shown) and seams (see Fig. 4 at 80) in the disposable, absorbent, pull-on pants. The backsheet is typically a liquid impervious film (Fig. 2 at 56), to prevent exudates from escaping. The liquid impervious film is impervious to liquids (e.g., urine) and is preferably manufactured from a thin plastic film. More preferably, the liquid impervious film permits vapors to escape from the disposable, absorbent, pull-on pants. In a preferred embodiment, the liquid impervious film is a microporous polyethylene film, such as PG-P, manufactured by Mitsui Toatsu Chemicals, Inc. (Nagoya, Japan).

A suitable material for the liquid impervious film is a thermoplastic film having a thickness of from about 0.012 mm (0.5 mil) to about 0.051 mm (2.0 mils), preferably including polyethylene or polypropylene. Preferably, the liquid impervious film has a basis weight of from about 5 g/m to about 50 g/m² for cold tentered microporous films. A preferred liquid impervious film, with a basis weight of about 40 g/m², is "BR106 type White 40 gsm Microporous," available from Clopay Film Products of Cincinnati, Ohio, U.S.A. Preferred hot tentered microporous films, which are also useful herein, typically have a basis weight of from about 5 g/m to about 35 g/m . Herein, "basis weight" is the weight of one square meter of material. However, it should be noted that other flexible liquid impervious materials may be used. Herein, "flexible" refers to materials which are compliant and which will readily conform to the general shape and contours of the wearer's body. In a preferred embodiment, the backsheet is compatible with other materials (e.g., component materials in the topsheet) used, in terms of its design/process, for forming ventilation holes (not shown) and seams (see Fig. 4 at 80) in the disposable, absorbent, pull-on pants. In a preferred embodiment, a disposable tape (not shown) is additionally joined to the outer surface of the backsheet, to provide for convenient disposal after soiling.

In Fig. 1 , the leg openings, 32, contain an optional elasticized leg cuff, 44, for providing improved containment of liquids and other body exudates. The elasticized leg cuff may include several different embodiments for reducing the leakage of body exudates in the leg regions. These elasticized leg cuffs are sometimes also referred to as leg bands, side flaps, barrier cuffs, elastic cuffs, or gasketing cuffs. U.S. Patent No. 3,860,003 to Buell, above, describes a disposable diaper which provides a contractible leg opening having a side flap and one or more elastic members to provide an elasticized leg cuff. U.S. Patent No. 4,909,803 entitled "Disposable Absorbent Article Having Elasticized Flaps" issued to Aziz, et al., on March 20, 1990, describes a disposable diaper having "stand-up" elasticized flaps (barrier cuffs) to improve the containment of the leg regions. U.S. Patent No. 4,695,278 entitled "Absorbent Article Having Dual Cuffs" issued to Lawson on September 22, 1987; and U.S. Patent No. 4,795,454 entitled "Absorbent Article Having Leakage-Resistant Dual Cuffs" issued to Dragoo on January 3, 1989, describe disposable diapers having dual cuffs including a gasketing cuff and a barrier cuff. U.S. Patent No. 4,704,115 entitled "Disposable Waist Containment Garment" issued to Buell on November 3, 1987, discloses a disposable diaper, or incontinence garment having side-edge- leakage-guard gutters configured to contain free liquids within the disposable, absorbent, pull-on pants. Such elasticized leg cuffs and structures are preferred herein.

While each elasticized leg cuff may be configured so as to be similar to any of the leg bands, side flaps, barrier cuffs, and/or elastic cuffs described above, Fig. 1 shows an elasticized leg cuff, 44, which includes an elastic gasketing cuff, 46, with an elastic strand, 48, as described in U.S. Patent Nos. 4,695,278 and 4,795,454, referred to above. Preferably at least one elastic gasketing cuff, and at least one elastic strand are present in the elasticized leg cuff.

In Fig. 1 , the back top edge, 36, includes an elasticized waistband, 50, that provides improved fit and containment. The elasticized waistband is that portion or zone which is intended to elastically expand and contract to dynamically fit the wearer's waist; thus, the elasticized waistband is typically located on, or adjacent to the front top edge and/or the back top edge. Preferably, the elasticized waistband is substantially parallel to the front top edge and/or the back top edge. If present, the elasticized waistband preferably extends longitudinally from the back region, toward the crotch region. The present invention preferably includes at least one elasticized waistband, more preferably two elasticized waistbands, with one positioned in the back region, and one positioned in the front region. Alternatively, the elasticized waistband may be formed of one, preferably multiple, elastic strand(s) which substantially encircle the waist opening. However, other embodiments may be constructed with a single elasticized waistband, or no elasticized waistband at all. The elasticized waistband may be constructed in a number of different configurations, including those described in U.S. Patent No. 4,515,595 entitled "Disposable Diapers with Elastically Contractible Waistbands" issued to Kievit, et al., on May 7, 1985 and the above-referenced U.S. Patent No. 5,151 ,092 issued to Buell.

The elasticized waistband may include materials that have been "prestrained" or "mechanically prestrained" (i.e., subjected to some degree of localized pattern mechanical stretching to permanently elongate the material). These materials may be prestrained using deep embossing techniques as are known in the art. Alternatively, these materials may be prestrained by directing the material through an incremental mechanical stretching system as described in U.S. Patent No. 5,330,458 entitled "Absorbent Article With Elastic Feature Having A Portion Mechanically Prestrained" issued to Buell, et al., on July 19, 1994. The materials are then allowed to return to their substantially untensioned condition, thus forming a "zero strain" (e.g., a substantially untensioned condition) stretch material that is extensible, at least up to the point of initial stretching. Examples of zero strain materials are disclosed in U.S. Patent No. 2,075,189 issued to Galligan on March 30, 1937; U.S. Patent No. 3,025,199 issued to Harwood on March 13, 1962; U.S. Patent Nos. 4,107,364 and 4,209,563 issued to Sisson on August 15, 1978 and June 24, 1980, respectively; U.S. Patent No. 4,834,741 issued to Sabee on May 30, 1989; and U.S. Patent No. 5,151 ,092 issued to Buell, et al., on September 29, 1992.

In Fig. 1 , the absorbent chassis, 18, contains two optional elastically extensible side panels, 52, which may expand and contract in order to provide a more comfortable and contouring fit suitable for the wearer. Herein, "extensible" refers to materials that are capable of extending in at least one direction to a certain degree without undue rupture. Herein, "elasticity" and "elastically extensible" refer to extensible materials that have the ability to return to approximately their original dimensions after the force that extended the material is removed. Herein, any material or element described as "extensible" may also be elastically extensible unless otherwise provided.

The elastically extensible side panels, 52, initially conformably fit the absorbent chassis, 18, to the wearer. Preferred elastically extensible side panels sustain this fit throughout the entire time of wear. More preferred elastically extensible side panels sustain this fit well past when the disposable, absorbent, pull-on pants have been loaded with exudates. Thus, the elastically extensible side panel may be formed in a wide variety of regular and irregular sizes and shapes (e.g., triangular, rectangular, other quadrilateral, and other polygon). The present invention preferably contains at least one, more preferably at least two, and even more preferably two to four elastically extensible side panels.

In the present invention, the elastically extensible side panel, the elasticized gasketing cuff, and/or the elasticized waistband is typically formed of an elastomeric material, an extensible sheet or film material, an elastic strand, a prestrained material, or combinations thereof. Preferably, the elastomeric mateπal is extensible in at least one direction, preferably in the lateral direction, and more preferably in the lateral direction and the longitudinal direction to generate a retention (or sustained) force that is optimal to prevent the absorbent chassis from drooping, sagging, or sliding down from its position on the torso, without causing the red marking on the skin of the wearer. A preferred elastomeric material is a plane elastomeric material. Herein, "plane elastomeric material" refers to elastomeric materials which continuously extend in two dimensional directions. Preferred plane elastomeric materials include a scrim, a perforated (or apertures formed) film, an elastomeric woven or nonwoven, and the like. In a preferred embodiment, the plane elastomeric material includes at least a portion that has a nonuniform lateral width. Preferably, the lateral width of the plane elastomeric material increases towards the leg opening, 32. The elastomeric material provides good fitness by generating the optimal retention (or sustained) force at the waist and side areas of the wearer. Elastomeric materials which have been found to be especially suitable are styrenic block copolymer based scrim materials, perforated (or apertured) elastic films, preferably with a thickness of from about 0.05 mm to about 1.0 mm (0.002 inch - 0.039 inch). Another suitable elastomeric material includes "live" synthetic or natural rubber, other synthetic or natural rubber foams, elastomeric films (including heat shrinkable elastomeric films), elastomeric woven or nonwoven webs, elastomeric composites, or the like. In a preferred embodiment, the elastomeric material is a porous, macroscopically-expanded, three-dimensional elastomeric web having a continuous first surface and a discontinuous second surface. The detail of such a structure and the method to manufacture is disclosed in U.S. Patent Application No.08/816,106, filed March 14, 1997. A preferred porous elastomeric material is manufactured by the Tredegar Film Products under the designation X-25007. A preferred elastomeric scrim is manufactured by the Conwed Plastics Company (Minneapolis, Minn., U.S.A.) under the designation XO2514. This material has about 12 elastic strands per inch in the structural direction B and about 7 elastic strands per inch in the structural direction D.

A highly preferred elastomeric material is the extensible laminate structure described in WO 98/55292 to Langdon, et al., published on December 10, 1998, entitled "Extensible Laminate Structures", corresponding to co-pending U.S. Application No. PCT/US97/09943 filed on June 6, 1997. A preferred process for making this extensible laminate structure is described in WO 98/55298 to Langdon, et al., published on December 10, 1998, entitled "Methods For Forming Extensible Laminate Structures", corresponding to co-pending U.S. Application No. PCT/US97/09947 filed on June 6, 1997. The extensible laminate structure contains a first coverstock layer, a second coverstock layer, and an elastomeric layer, such as an elastomeric scrim, between the first and the second coverstock layers. The elastomeric layer is joined between the first and second coverstock layers and along edge regions, to provide side anchor zones along the edge regions of the laminate structure. This preferred extensible laminate structure is breathable, and yet substantially eliminates creep and delamination caused by repeated in-use stretching. Such properties make the extensible laminate structure particularly useful for use in the pants-type garments of the present invention.

Fig. 2 shows a partially cut-away plan view of the embodiment shown in Fig. 1, in its flat uncontracted condition, with the topsheet, 20, facing the viewer. The front side edges 26 and 26', have yet to be joined to the back side edges, 38 and 38', to form the disposable, absorbent, pull-on pants of the present invention. In Fig. 2, it is easily seen that the front top edge, 24, is below the imaginary front straight line, 30, as defined herein. The absorbent chassis, 18, includes the topsheet, 20, the backsheet, 22, associated with the topsheet, 20, and an absorbent core, 54, positioned between the topsheet, 20, and the backsheet, 22. The absorbent core may be any absorbent member which 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. The absorbent core may be manufactured in a wide variety of sizes and shapes (e.g., rectangular, hourglass, "T"-shaped, asymmetric, etc.) and from a wide variety of liquid-absorbent materials commonly used in disposable pull-on garments and other absorbent articles, such as comminuted wood pulp which is generally referred to as airfelt. Examples of other suitable absorbent materials include creped cellulose wadding; meltblown polymers including coform; chemically stiffened, modified or cross-linked cellulosic fibers; tissue including tissue wraps and tissue laminates; absorbent foams; absorbent sponges; superabsorbent polymers; absorbent gelling materials; or any equivalent material or combinations of materials. Accordingly, the absorbent chassis will typically contain an absorbent core disposed between the topsheet and the backsheet. The topsheet and the backsheet are typically larger in both length and width than the absorbent core, and extend beyond the edges of the absorbent core, to thereby form the leg openings (Fig. 1 at 32).

In a preferred embodiment of the invention, the absorbent core has, in the uncontracted state of the disposable, absorbent, pull-on pants, an area ratio of the core area to the garment area of greater than about 25%, more preferably greater than about 40%. The "core area" is defined as the total area of the body- facing surface of the absorbent core in the uncontracted state of the disposable, absorbent, pull-on pants. The periphery of the body-facing surface of the absorbent core is determined by the outline of aggregates of primary absorbent materials used in the absorbent core. Herein, "primary absorbent material" refers to absorbent materials which occupy more than about 80% in dry state volume of the absorbent core. In a preferred embodiment, a wood pulp (e.g., airfelt) is considered a primary absorbent material of the absorbent core and defines the periphery of the body-facing surface of the absorbent core, thus defining the core area of the absorbent core. The other primary absorbent materials may include creped cellulose wadding; meltblown polymers including coform; chemically stiffened, modified or cross-linked cellulosic fibers; tissue including tissue wraps and tissue laminates; absorbent foams; absorbent sponges; superabsorbent polymers; absorbent gelling materials; or any equivalent material or combinations of materials.

The garment area is defined as the total area of the body-facing surface of the disposable, absorbent, pull-on pants in the uncontracted state. Therefore, the area ratio is calculated as follows: AR = CA / GA x 100 wherein,

AR the area ratio (%) CA the core area (crτ)2) GA the total area (cιτ)2) In a preferred embodiment for infant use, the absorbent core has a core area of less than about 450 cm2, more preferably less than about 425 cιτι2. Preferably, the absorbent core has a maximum core width of less than about 12 cm, more preferably less than about 11 cm. Herein, "core width" refers to the lateral distance from one side edge to the other side edge of the absorbent core. The configuration and construction of the absorbent core may vary. For example, the absorbent core may have varying caliper zones, a hydrophilic gradient, a superabsorbent gradient, or lower average density and lower average basis weight acquisition zones; or may include one or more layers or structures. Furthermore, the size and absorbent capacity of the absorbent core may also be varied to accommodate wearers ranging from infants through adults. However, the total absorbent capacity of the absorbent core should be compatible with the design loading and the intended use of the disposable, absorbent, pull-on pants. A preferred embodiment of the absorbent core is a modified hourglass- shaped absorbent core, having ears in the front region and back region. Other exemplary absorbent structures for use as the absorbent core that have achieved wide acceptance and commercial success are described in U.S. Patent No. 4,610,678 entitled "High-Density Absorbent Structures" issued to Weisman et al. on September 9, 1986; U.S. Patent No. 4,673,402 entitled "Absorbent Articles With Dual-Layered Cores" issued to Weisman, et al., on June 16, 1987; U.S. Patent No. 4,888,231 entitled "Absorbent Core Having A Dusting Layer" issued to Angstadt on December 19, 1989; and U.S. Patent No. 4,834,735, entitled "High Density Absorbent Members Having Lower Density and Lower Basis Weight Acquisition Zones", issued to Alemany, et al., on May 30, 1989.

The backsheet is preferably positioned adjacent the outer-facing surface of the absorbent core and is preferably, but not necessarily, joined thereto by any suitable attachment means known in the art. For example, the backsheet may be secured to the absorbent core by a uniform continuous layer of adhesive, a patterned layer of adhesive, or an array of separate lines, spirals, or spots of adhesive. Adhesives which have been found to be satisfactory are manufactured by H. B. Fuller Company of St. Paul, Minnesota, U.S.A., and marketed as HL-1358J. An example of a suitable attachment means including an open pattern network of filaments of adhesive is disclosed in U.S. Patent No. 4,573,986 entitled "Disposable Waste-Containment Garment", which issued to Minetola, et al., on March 4, 1986. Another suitable attachment means including several lines of adhesive filaments swirled into a spiral pattern is illustrated by the apparatus and methods shown in U.S. Patent No. 3,911 ,173 issued to Sprague, on October 7, 1975; U.S. Patent No. 4,785,996 issued to Ziecker, et al., on November 22, 1978; and U.S. Patent No. 4,842,666 issued to Werenicz on June 27, 1989. Alternatively, the attachment means may include heat bonds, pressure bonds, ultrasonic bonds, dynamic mechanical bonds, or any other suitable attachment means or combinations of these attachment means as are known in the art.

In the cut-away portion of Fig. 2, the topsheet, 20, is removed to reveal the absorbent core, 54, two elastic strands, 48, and the backsheet, 22. The liquid backsheet, 22, includes a liquid impervious film, 56, which extends longitudinally in the front region, 12, the back region, 14, and crotch regions, 16. In this preferred embodiment, the liquid impervious film does not laterally extend to the front side edges, 26 and 26', nor the back side edges, 38 and 38'.

In Fig. 2, each optional elasticized leg cuff, 44, further includes structural components such as an inner barrier cuff, 58, each including a barrier flap, 60, and a spacing means, 62, which are described in the above-referenced U.S. Patent No. 4,909,803. The inner barrier cuff, 58, captures exudates and reduces leakage of the exudates from the absorbent chassis, 18. During use, the inner barrier cuff, barrier flap, and/or the spacing means may also direct any exudates towards the absorbent core, where they are partially or completely absorbed, further reducing leakage. Preferably, at least one pair, more preferably two pairs of inner barrier cuffs are included in the present invention.

Fig. 3 is a cross-sectional view of a preferred embodiment taken along the section line 3-3 of Fig. 2. Although Fig. 3 depicts only the structure of the absorbent chassis and the front region, it is preferred that a similar structure is also provided in the back region. As shown in Fig. 3, the backsheet, 22, preferably further includes a nonwoven outer cover, 64, which is joined with the outer-facing (i.e., away from the body of the wearer) surface, 66, of the liquid impervious film, 56, to form a laminate (i.e., the backsheet, 22). If present, the nonwoven outer cover is positioned at the outermost portion of the disposable, absorbent, pull-on pants, and covers at least a portion, preferably almost all of the outermost portion thereof. In a preferred embodiment, the nonwoven outer cover is a carded nonwoven web, for example, obtainable from Havix Co., Ltd. (Gifu, Japan), as E-2341. This nonwoven outer cover is made of bi-component fibers of a polyethylene (PE) and a polypropylene (PP). The ratio of PE/PP is about 50/50. The PE/PP bi-component fiber has the dimension of 2d x 51 mm. Another preferred carded nonwoven web is obtainable from Chisso Corp. (Moriyama, Japan), made of bi-component fibers of PE and PP, in a PE/PP ratio of about 50/50. In another preferred embodiment, the nonwoven web is a spunbonded nonwoven web, for example, obtainable from Mitsui Petrochemical Industries, Ltd. (Tokyo, Japan). The nonwoven web is made of bi-component fibers of PE and PP, in a PE/PP ratio of about 80/20. The PE/PP bi-component fiber has the thickness is approximately 2.3d. An exemplary preferred nonwoven material is manufactured by Fiberweb North America, Inc. (Simpsonville, South Carolina, U.S.A.) under the designation Sofspan 200. This material has a basis weight of about 33 g/m². Another highly preferred nonwoven material is Sawabond 4111 available from Christian Heinrich Sandier GmbH & Co. KG, Schwarzenbach, Germany. Alternatively, highly strainable nonwoven materials may also be used. The nonwoven outer cover, 64, may be joined to the liquid impervious film,

56, by any suitable attachment means known in the art. In Fig. 3 the nonwoven outer cover, 64, is secured to the edge, 68, of the liquid impervious film, 56, by an optional adhesive, 70. The adhesive may be a uniform continuous layer of adhesive, a patterned layer of adhesive, and/or an array of separate lines, spirals, or spots of adhesive. Suitable adhesives include a hotmelt adhesive obtainable from Nitta Findley Co., Ltd. (Osaka, Japan), as H-2128, and a hotmelt adhesive obtainable from H.B. Fuller Japan Co., Ltd. (Osaka, Japan), as JM- 6064. Preferably, the adhesive is applied, with methods and equipment known in the art, in a spiral glue pattern or as a meltblown adhesive, more preferably the adhesive is applied as a meltblown adhesive. In a preferred embodiment, the adhesive is a flexible adhesive with an amorphous and crystallizing component. Such a preferred adhesive is made by Nitta Findley Co., Ltd. (Osaka, Japan), under the designation H2085F. Alternatively, the elastic member may be joined to the edge of the liquid impervious film by any other bonding means known in the art which include heat bonds, pressure bonds, ultrasonic bonds, dynamic mechanical bonds, or combinations thereof.

Furthermore, in Fig. 3, an extended part, 72, of the absorbent chassis, 18, is located between the absorbent core, 54, and the front side edge (not shown in Fig. 3). The extended part, 72, is formed by an elastic member, 74, laminated between an extended part of the barrier flap, 60, and the nonwoven outer cover, 64. The elastic member, 74, includes a plane elastomeric material. In a preferred embodiment, the plane elastomeric material has an identical shape and dimensions as the elastic member, 74. In a highly preferred embodiment, the lamination of the extended part of the barrier flap, the elastic member, and the nonwoven outer cover forms a extensible laminate structure according to WO

98/55292 to Langdon, et al., described above. The extensible laminate structure in turn forms at least part of an elastically extensible side panel (see Fig. 1 at 52).

In Fig. 3, the elastic member, 74, is operatively joined to the nonwoven outer cover, 64, to allow the elastic member, 74, to be elastically extensible in at least the lateral direction. Alternatively, the elastic member may be operatively joined only to the extended part of the barrier flap, or may be joined to both the nonwoven outer cover as well as the extended part of the barrier flap. In a preferred embodiment, the elastic member is operatively joined to the nonwoven outer cover and/or the extended part of the barrier flap while in a substantially untensioned (zero strain) condition.

The elastic member may be operatively joined to the nonwoven outer cover, and/or the extended part by using either an intermittent bonding configuration or a substantially continuous bonding configuration. Herein, "intermittently" bonded laminate web means a laminate web wherein the plies are initially bonded to one another at discrete spaced apart points or a laminate web wherein the plies are substantially unbonded to one another at discrete spaced apart areas. Conversely, a "substantially continuously" bonded laminate web means a laminate web wherein the plies are initially bonded substantially continuously to one another throughout the areas of interface. It is preferred that the stretch laminate be bonded over all or a significant portion of the stretch laminate so that the inelastic webs (i.e., the nonwoven outer cover, and/or the extended part) elongate or draw without causing rupture, and the layers of the stretch laminates are preferably bonded in a configuration that maintains all of the layers of the stretch laminate in relatively close adherence to one another after the incremental mechanical stretching operation. Consequently, the elastic member and the other plies of the stretch laminate are preferably substantially continuously bonded together using an adhesive. In a particularly preferred embodiment, the adhesive selected is applied with a control coat spray pattern at a basis weight of about 7.0 grams/m². The adhesive pattern width is about 6.0 cm. The adhesive is preferably an adhesive such as H2085F, available from Nitta Findley Co., Ltd. (Osaka, Japan), described above. Alternatively, the elastic member and any other components of the stretch laminates may be intermittently or continuously bonded to one another using heat bonding, pressure bonding, ultrasonic bonding, dynamic mechanical bonding, or any other method as is known in the art.

Typically, after the elastic member is operatively joined to at least one of the nonwoven outer cover or the extended part, at least a portion of the resultant composite stretch laminate is then subjected to mechanical stretching sufficient to permanently elongate the non-elastic components. The composite stretch laminate is then allowed to return to its substantially untensioned condition. At least one part of the absorbent chassis is thus formed into a "zero strain" stretch laminate.

Alternatively, the elastic member could be operatively joined in a tensioned condition and then subjected to mechanical stretching; although this is not as preferred as a "zero strain" stretch laminate. Herein, "zero strain" stretch laminate refers to a laminate including at least two plies of material which are secured to one another along at least a portion of their coextensive surfaces while in a substantially untensioned ("zero strain") condition; one of the plies including a material which is stretchable and elastomeric (i.e., will return substantially to its untensioned dimensions after an applied tensile force has been released) and a second ply which is elongatable (but not necessarily elastomeric) so that upon stretching the second ply will be, at least to a degree, permanently elongated so that upon release of the applied tensile forces, it will not fully return to its original undeformed configuration. The resulting stretch laminate is thereby rendered elastically extensible, at least up to the point of initial stretching, in the direction of initial stretching. Particularly preferred methods and apparatus used for making stretch laminates utilize meshing corrugated rolls to mechanically stretch the components. Particularly preferred apparatus and methods are disclosed in U.S. Patent No. 5,167,897 issued to Weber, et al., on December 1 , 1992; U.S. Patent No. 5,156,793 issued to Buell, et al., on October 20, 1990; and U.S. Patent No. 5,143,679 issued to Weber, et al., on September 1 , 1992.

In the preferred embodiment of Fig. 3, the absorbent chassis, 18, further includes an acquisition/distribution layer, 76, and an acquisition/distribution core, 78. The acquisition/distribution layer, 76, is provided to help reduce the surface wetness of the topsheet, 20. The acquisition/distribution layer preferably includes carded, resin bonded hiloft nonwoven materials such as, for example, available as Code No. FT-6860 from Polymer Group, Inc., North America (Landisiville, New Jersey, U.S.A.), which is made of polyethylene terephthalate fibers of 6 dtex, and has a basis weight of about 43 g/m^. A preferable example for the acquisition/distribution layer and the acquisition/distribution core is disclosed in EP 0797968A1 to Kurt, et al., published on October 1 , 1997.

The acquisition/distribution core, 78, may be formed of fibers, preferably chemically stiffened fibers, positioned over the absorbent core, 54, thereby forming a dual core system. In a preferred embodiment, the fibers are hydrophilic chemically stiffened cellulosic fibers. Herein, "chemically stiffened fibers" means any fibers which have been stiffened by chemical means to increase stiffness of the fibers under both dry and aqueous conditions. Such means include the addition of chemical stiffening agents which, for example, coat and/or impregnate the fibers. Such means also include the stiffening of the fibers by altering the chemical structure of the fibers themselves, e.g., by cross-linking polymer chains. The fibers utilized in the acquisition/distribution core may also be stiffened by means of a chemical reaction. For example, crosslinking agents may be applied to the fibers which, subsequent to application, are caused to chemically form intrafiber crosslink bonds. These crosslink bonds may increase the stiffness of the fibers. Whereas the utilization of intrafiber crosslink bonds to chemically stiffen the fibers is preferred, it is not meant to exclude other types of reactions for chemical stiffening of the fibers. In the more preferred fibers, chemical processing includes intrafiber crosslinking with crosslinking agents while such fibers are in a relatively dehydrated, defibrated (i.e. individualized), twisted, curled condition. Suitable chemical stiffening agents include monomeric crosslinking agents including, but not limited to, C₂-C₈ dialdehydes and C₂-C₈ monoaldehydes having an acid functionality may be employed to form the cosslinking solution. These compounds are capable of reacting with at least two hydroxyl groups in a single cellulose chain or on proximately located cellulose chains in a single fiber. Such crosslinking agents contemplated for use in preparing stiffened cellulose fibers include, but are not limited to, glutaraldehyde, glyoxal, formaldehyde, and glyoxylic acid. Other suitable stiffening agents are polycarboxylates, such as citric acid. Polycarboxylic stiffening agents and a process for making stiffened fibers from them are described in U.S. Patent No. 5,190,563, entitled "Process for Preparing Individualized, Polycarboxylic Acid crosslinked Fibers" issued to Herron on March 2, 1993. The effect of crosslinking under these conditions is to form fibers which are stiffened and which tend to retain their twisted, curled configuration during use in the absorbent articles herein. Such fibers, and processes for making them are cited in the above incorporated patents.

Preferred dual core systems are disclosed in U.S. Patent No. 5,234,423, entitled "Absorbent Article With Elastic Waist Feature and Enhanced Absorbency" issued to Alemany, et al., on August 10, 1993; and in U.S. Patent No. 5,147,345, entitled "High Efficiency Absorbent Articles For Incontinence Management" issued to Young, et al., on September 15, 1992. In a preferred embodiment, the acquisition/distribution core includes chemically treated stiffened cellulosic fiber material, available from Weyerhaeuser Co. (U.S.A.) under the trade designation of "CMC". Preferably, the acquisition/distribution core has a basis weight of from about 40 g/m² to about 400 g/m², more preferably from about 75 g/m² to about 300 g/m².

Fig. 4 is a side view of a baby with an extended abdomen wearing an embodiment of the present invention. In Fig. 4, the absorbent chassis, 18, is formed into a pull-on diaper by joining the front side edge, 26, with the back side edge, 38, in order to form a waist opening, 34, and two leg openings, 32. (Only one leg opening, 32, is visible in Fig. 4.) As in Fig. 1 , the front end point, 28 corresponds with the back end point, 40. In Fig. 4 it can be seen that in the front region, 12, the front top edge, 24, is below the front end point, 28, and thus is also below the imaginary front straight line, 30. As noted above, this avoids bunching and sagging caused by the baby's extended abdomen. As with Fig. 1 , the imaginary front straight line, 30, and the imaginary back straight line, 42, are curved so as to follow the curvature of the diaper when it is ready to be worn; however, the imaginary front straight line and the imaginary back straight line remain straight, when the diaper is placed in the uncontracted state shown in the plan view of Fig. 2. Thus, in a preferred embodiment, the front top edge, 24, is designed to be positioned at, or below the wearer's abdominal crease, more preferably, the front top edge, 24, is designed to be positioned at, or below the wearer's abdominal crease (see Fig. 6 at point C) and the back top edge, 36, is designed to be positioned at the wearer's lumbar curve of the back (see Fig. 6 at point B).

The front side edge, 26, joins with the back side edge, 38, to form a seam, 80, preferably a butt-seam, or an overlapping seam. A preferred seam is formed by a plurality of discrete spaced apart seaming bonds which are formed on the seam (otherwise known as a seaming line). The discrete seaming bonds form a substantially bonded portion starting from the waist opening, and an unbonded portion starting from the leg opening. Herein, "substantially bonded portion" refers to portions which are intermittently and/or continuously joined to other materials to contribute to the formation of the leg and waist openings. Herein, "unbonded portion" refers to portions which are not joined to other materials. In an alternative embodiment, the seam may be formed by a continuous bond which continuously bonds the front side edge and back side edge. The continuous bond may also form a substantially bonded portion starting from the waist opening, and an unbonded portion starting from the leg opening. Preferred disposable, absorbent, pull-on diapers for infants have an unbonded portion from the leg opening of from about 4 mm to about 20 mm, more preferably from about 8 mm to about 15 mm, yet more preferably from about 10 mm to about 13 mm in length.

In the back region, 14, the back top edge, 36, is above the back end point, 40, and thus is also above the imaginary back straight line, 42. This reduces the chance of BM leakage as the baby repeatedly sits down and stands up. In Fig. 4, the optional elastically extensible side panels, 52, provide a snug, yet comfortable fit.

As may be seen from the highly preferred embodiment of Fig. 4, the waist opening, 34, continues in an unbroken, smooth line at the point where the front side edge, 26, joins the back side edge, 38. This type of waist opening, 34, is described as a continuous waist opening. While the continuous waist opening may be either straight across the seam, 80, or may be slightly curved, it does not contain any right angles, nor any acute angles formed by the front top edge, 24, the front end point, 28, the back end point, 40, and the back top edge, 36, while in the in-use configuration. Such a continuous waist opening provides a primary line of tension which helps maintain the position of the disposable, absorbent, pull-on pants of the present invention on the wearer. This primary line of tension preferably extends around the lumbar curve of the back (i.e., the small of the back), over the iliac crest of the hips, to below the line of the abdominal crease. This corresponds to a zone of minimal changing body dimensions, and thus a sustained in-use wearing position, as the wearer moves, sits down, stands up, etc. A primary line of tension corresponding to the continuous waist opening also imparts an upward anchoring force on the absorbent chassis, 18, which further maintains its position on the wearer. Thus, in Fig. 4, the continuous waist opening follows a preferred angle of fit (see Fig. 6 at α) which further reduces slippage of the disposable, absorbent, pull-on pants, 10, of the present invention. Accordingly, such a continuous waist opening is highly preferred in the present invention. In a preferred embodiment (not shown), the primary line of tension is provided by multiple elastic strands running substantially parallel to substantially all of the waist opening.

Fig. 5 is a simplified plan view of one preferred embodiment of the disposable, absorbent, pull-on pants of the present invention. In the front region, 12, of Fig. 5, only a portion of the front top edge, 24, is below the imaginary front straight line, 30, which is defined by connecting the front end points, 28 and 28', of the front side edges, 26 and 26', respectively. In the back region, 14, the back side edges, 38 and 38', contain back end points, 40 and 40', respectively. The back top edge, 36, is straight, and corresponds to the imaginary back straight line, 42, which is defined by connecting the back end points, 40 and 40'. Thus, in Fig. 5, the back top edge, 36, is not above the imaginary back straight line, 42.

Fig. 6 is a side view of a body of a wearer, such as an infant, showing a preferred angle of fit of the present invention. Fig. 6 shows an angle, α, between the line AB (e.g., a lateral line, with respect to the absorbent chassis) connecting the navel (point A), the lumbar curve of the back (point B), and line BC connecting the lumbar curve of the back (point B) to a point at the abdominal crease (point C). This angle, α, is greater than about 5°, preferably from about 5° to about 60°, more preferably from about 5° to about 30°, even more preferably from about 10° to about 20°, and most preferably about 15°. In a highly preferred embodiment of the present invention, during use, a portion of the front top edge corresponds to point C, while a portion of the back top edge corresponds to point B. In this embodiment (see for example, Fig. 4), the disposable, absorbent, pull-on pants are less likely to slip, sag, or otherwise change position, even during sustained periods of use. Without intending to be limited by theory, it is believed that in addition to minimizing forces which tend to cause the disposable, absorbent, pull-on pants to sag, such an embodiment also provides an upward anchoring force which tends to pull the present invention up on the body. This in turn, maintains the disposable, absorbent, pull-on pants in place.

It is understood that the embodiments described herein are for illustrative purposes only and that various modifications or changes will be suggested to one skilled in the art without departing from the scope of the present invention.

Claims

WHAT IS CLAIMED IS:

1. Disposable, absorbent, pull-on pants having a front region, a back region and a crotch region between the front region and the back region, comprising: an absorbent chassis having a front top edge and two opposing front side edges in the front region, each front side edge having a front end point, the front top edge being disposed between the front end points, wherein an imaginary front straight line is defined by connecting the two front end points with a straight line, and wherein the front top edge has at least a portion which is below the imaginary front straight line, wherein the front region is joined to the back region to form two leg openings and a waist opening.

2. The disposable, absorbent, pull-on pants of Claim 1 , wherein the absorbent chassis further comprises a back top edge and two opposing back side edges in the back region, each back side edge having a back end point, the back top edge being disposed between the back end points, wherein an imaginary back straight line is defined by connecting the two back end points with a straight line, and wherein the back top edge has at least a portion which is above the imaginary back straight line.

3. The disposable, absorbent, pull-on pants of Claim 1 , wherein the waist opening is a continuous waist opening.

4. The disposable, absorbent, pull-on pants of Claim 1 , wherein the lowest point of the front top edge is at least about 5 mm below the imaginary front straight line.

5. The disposable, absorbent, pull-on pants of Claim 1 , wherein each leg opening further comprises an elasticized leg cuff.

6. The disposable, absorbent, pull-on pants of Claim 1 , further comprising an elastomeric material.

7. The disposable, absorbent, pull-on pants of Claim 1 , further comprising an absorbent core.

8. The disposable, absorbent, pull-on pants of Claim 1 , further comprising an elastically extensible side panel.

9. The disposable, absorbent, pull-on pants of Claim 2, wherein the back top edge is complementary to the front top edge.

10. Disposable, absorbent, pull-on pants having a front region, a back region and a crotch region between the front region and the back region, comprising: an absorbent chassis having a front top edge and two opposing front side edges in the front region, each front side edge having a front end point, the front top edge being disposed between the front end points, wherein an imaginary front straight line is defined by connecting the two front end points with a straight line, and wherein the front top edge has at least a portion which is below the imaginary front straight line, the absorbent chassis having a back top edge and two opposing back side edges in the back region, each back side edge having a back end point, the back top edge being disposed between the back end points, wherein an imaginary back straight line is defined by connecting the two back end points with a straight line, and wherein the back top edge has at least a portion which is above the imaginary back straight line; and an absorbent core, wherein the front region is joined to the back region to form two leg openings and a waist opening, wherein each leg opening comprises an elasticized leg cuff, and wherein the back top edge is complementary to the front top edge.