WO2000019950A1 - Disposable garment having elastic laminate including polystyrene thermoplastic elastomer and nonwoven layer containing polyester - Google Patents

Disposable garment having elastic laminate including polystyrene thermoplastic elastomer and nonwoven layer containing polyester

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Publication number
WO2000019950A1
WO2000019950A1 PCT/US1998/020914 US9820914W WO2000019950A1 WO 2000019950 A1 WO2000019950 A1 WO 2000019950A1 US 9820914 W US9820914 W US 9820914W WO 2000019950 A1 WO2000019950 A1 WO 2000019950A1
Authority
WO
Grant status
Application
Patent type
Prior art keywords
layer
nonwoven
preferred
preferably
garment
Prior art date
Application number
PCT/US1998/020914
Other languages
French (fr)
Inventor
Kazuyuki Ohnishi
Yoko Mizutani
Ebrahim Rezai
Original Assignee
The Procter & Gamble Company
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date

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Classifications

    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61FFILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, E.G. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F13/00Bandages or dressings; Absorbent pads
    • A61F13/15Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators
    • A61F13/45Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the shape
    • A61F13/49Absorbent articles specially adapted to be worn around the waist, e.g. diapers
    • A61F13/49007Form-fitting, self-adjusting disposable diapers
    • A61F13/49009Form-fitting, self-adjusting disposable diapers with elastic means
    • A61F13/49011Form-fitting, self-adjusting disposable diapers with elastic means the elastic means is located at the waist region
    • A61F13/49012Form-fitting, self-adjusting disposable diapers with elastic means the elastic means is located at the waist region the elastic means being elastic panels
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61FFILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, E.G. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F13/00Bandages or dressings; Absorbent pads
    • A61F13/15Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators
    • A61F13/45Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the shape
    • A61F13/49Absorbent articles specially adapted to be worn around the waist, e.g. diapers
    • A61F13/49007Form-fitting, self-adjusting disposable diapers
    • A61F13/49009Form-fitting, self-adjusting disposable diapers with elastic means
    • A61F13/49014Form-fitting, self-adjusting disposable diapers with elastic means the elastic means is located at the side panels
    • A61F13/49015Form-fitting, self-adjusting disposable diapers with elastic means the elastic means is located at the side panels the elastic means being elastic panels
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61FFILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, E.G. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F13/00Bandages or dressings; Absorbent pads
    • A61F13/15Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators
    • A61F13/45Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the shape
    • A61F13/49Absorbent articles specially adapted to be worn around the waist, e.g. diapers
    • A61F13/49007Form-fitting, self-adjusting disposable diapers
    • A61F13/49009Form-fitting, self-adjusting disposable diapers with elastic means
    • A61F13/4902Form-fitting, self-adjusting disposable diapers with elastic means characterised by the elastic material

Abstract

The present invention is directed to a disposable garment having a front region, a back region and a crotch region between the front region and the back region. The disposable garment comprises a chassis provided in the front, back and crotch regions and having edge lines in the front and back regions. The chassis includes a liquid pervious topsheet, a liquid impervious backsheet associated with the topsheet, and an absorbent core disposed between the topsheet and the backsheet. In one aspect of the present invention, the disposable garment further comprises at least one pair of extensible side panels extending laterally outward from the chassis in the front or back region. At least one of the side panels includes an elastic laminate elastically extensible at least in the lateral direction. The elastic laminate includes an elastomeric material having a first surface and a second surface opposing the first surface, the elastomeric material including a polystyrene thermoplastic elastomer; and a first nonwoven layer including component fibers which include a polyester. The elastomeric material is bonded to the first nonwoven layer through a continuous heat/pressure bond which is formed by application of a bonding temperature which is lower than the melting point of the polyester. In another aspect of the present invention, the disposable garment further comprises a waistband disposed along at least one of the end edges of the disposable garment. The waistband also includes an elastic laminate described above.

Description

DISPOSABLE GARMENT HAVING ELASTIC LAMINATE INCLUDING POLYSTYRENE THERMOPLASTIC ELASTOMER AND NONWOVEN LAYER CONTAINING POLYESTER

FIELD

The present invention relates to disposable garments. Examples of such disposable garments include disposable underwear, disposable diapers including pull-on diapers and training pants, and disposable panties for menstrual use. More specifically, the present invention relates to disposable garments which have an elastic laminate which includes an elastomeric material including a polystyrene thermoplastic elastomer and a nonwoven layer including a polyester.

BACKGROUND Infants and other incontinent individuals wear disposable garments such as diapers to receive and contain urine and other body exudates. One type of the disposable garments, which is often called as "tape type", has a fastener system to hold the disposable garment at the wearer's waist area. As the fastener system, either an adhesive tape system or a mechanical fastener system is often used. Recently, elastically stretchable ear panels tend to be preferably used in this type of disposable garment, because they can provide a better fit to the wearer's waist area by jointly working with the fastener system. Another type of disposable garments, which is often called as "pant type" or "pull-on", has fixed sides and has become popular for use on children able to walk and often who are toilet training. This type of pull-on garments has ear panels the edges of which are seamed together to form two leg openings and a waist opening. They also has a stretchable waistband disposed along at least one of the end edges of the disposable garments. These pull-on garments need to fit snugly about the waist and legs of the wearer without drooping, sagging or sliding down from position on the torso to contain body exudates. Examples of these pull-on garments are disclosed, for example, in U.S. Patent No. 5,171,239 to Igaue et al., U.S. Patent No. 4,610,681 to Strohbeen et al., WO 93/17648 published on September 16, 1993, U.S. Patent No. 4,940,464 to Van Gompel et al., U.S. Patent No. 5,246,433 to Hasse et al., and U.S. Patent No. 5,569,234 to Buell et al.

Good performance characteristics of such stretchable ear panels and waistband are important for these types of disposable garments. More specifically, the extension properties including the extension forces, recovery forces, retention forces, and available stretch (extension) of the ear panels and waistband are important considerations in the performance of the fitness for pull-on garments. The extension properties provide the applicator and the wearer with the overall perceived "stretchiness" during use. They also effect the ability of the applicator to achieve a suitable degree of application stretch (i.e., for a "normally" perceived tensioning of the diaper during application, the total amount of resultant stretch is that desired to achieve/maintain good conformity of fit).

To provide good performance characteristics in stretchable ear panels and waistband of disposable garments, elastic laminates which include an elastic material which has suitable properties have been studied and applied to disposable garments. For example, a PCT application No. PCT/US98/05895 entitled "Elastic Member And Disposable Garment Having Improved Fitness To Body During Entire Use" filed on March 26, 1998, discloses such elastic materials for disposable garments. As used herein, the term "elastic laminate" refers to an elastically stretchable two or more layered materials including at least one elastically stretchable single layer material. It is generally expected that disposable garments provide good fit to the body and/or skin of the user by using suitable elastic laminates during the entire use period of products. Those elastic laminates typically include, at least, a fibrous material layer

(e.g., a nonwoven layer) and an elastomeric material joined to the fibrous material layer. These materials are joined together typically through an adhesive (or glue) bond or a heat/pressure bond formed therebetween.

The adhesive bond is often used for forming elastic laminates. However, it tends to cause several problems in its manufacturing process(es) and its usage by consumers. For example, a manufacturing process which includes an adhesive application tends to become more complicated than that which does not need it (e.g., a heat/pressure bond process). In addition, the adhesive application tends to cause a contamination problem in manufacturing equipments or production lines because the use of adhesive. Further, an elastic laminate which uses an adhesive tends to cause an odor problem to consumers of disposable products, since some adhesive materials have a strong and/or uncomfortable smell.

The heat/pressure bond is preferably used for forming elastic laminates. For example, Japanese Laid-Open (Kokai) Patent Publication No. H 10-165437 published on June 23, 1998 discloses a disposable diaper which includes a three- layered structure of nonwoven/elastomer film/nonwoven which are bonded together through a number of non-continuous bonding points. However, this structure tends not to provide an enough bonding strength or toughness in the layered structure against a stress which is generated in the use of the diaper (or which may be applied in the manufacturing process), thereby causing a separation of the layered materials. It is believed that this problem is caused because the layered structure does not have enough peer strength required by the disposable products.

Based on the foregoing, there is a need for disposable garments which include ear panels and waistband employing an elastic laminate that provides an enough bonding strength or toughness between a elastomeric material and a fibrous material layer (or a nonwoven layer) against a stress which is generated in the use of disposable products diaper (or which may be applied in the manufacturing process).

SUMMARY

The present invention is directed to a disposable garment having a front region, a back region and a crotch region between the front region and the back region. The disposable garment comprises a chassis provided in the front, back and crotch regions and having edge lines in the front and back regions. The chassis includes a liquid pervious topsheet, a liquid impervious backsheet associated with the topsheet, and an absorbent core disposed between the topsheet and the backsheet.

In one aspect of the present invention, the disposable garment further comprises at least one pair of extensible side panels extending laterally outward from the chassis in the front or back region. At least one of the side panels includes an elastic laminate elastically extensible at least in the lateral direction. The elastic laminate includes an elastomeric material having a first surface and a second surface opposing the first surface, the elastomeric material including a polystyrene thermoplastic elastomer; and a first nonwoven layer including component fibers which include a polyester. The elastomeric material is bonded to the first nonwoven layer through a continuous heat/pressure bond which is formed by application of a bonding temperature which is lower than the melting point of the polyester.

In another aspect of the present invention, the disposable garment further comprises a waistband disposed along at least one of the end edges of the disposable garment. The waistband includes an elastic laminate elastically extensible at least in the lateral direction. The elastic laminate includes an elastomeric material having a first surface and a second surface opposing the first surface, the elastomeric material including a polystyrene thermoplastic elastomer; and a first nonwoven layer including component fibers which include a polyester. The elastomeric material is bonded to the first nonwoven layer through a continuous heat/pressure bond which is formed by application of a bonding temperature which is lower than the melting point of the polyester.

These and other features, aspects, and advantages of the present invention will become evident to those skilled in the art from reading of the present disclosure.

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 and which like designations are used to designate substantially identical elements, and in which:

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

Fig. 2 is a perspective view of another preferred embodiment of the disposable pull-on garment of the present invention in a typical in use configuration;

Fig. 3 is a simplified plan view of the embodiment shown in Fig. 2 in its flat uncontracted condition showing the various panels or zones of the garment;

Fig. 4 is a cross-sectional view of a preferred embodiment taken along the section line 4-4 of Fig. 3;

Fig. 5 is a cross-sectional view of a waistband 50 of a preferred embodiment taken along the section line 5-5 of Fig. 3; Fig. 6 is a cross-sectional view of a waistband 50 of another preferred embodiment;

Fig. 7 is a graph showing the two-cycles of hysteresis curves of an elastomeric material, in a preferred embodiment; Fig. 8 is a fragmentary enlarged perspective view of an elastic laminate of one preferred embodiment of the present invention, prior to being formed into the elastic laminate;

Fig. 9 is a enlarged perspective view of an elastic laminate of another embodiment of the present invention, wherein a portion of the nonwoven layer has been removed to show the bonded structure;

Fig. 10 is a fragmentary enlarged perspective view of an alternative embodiment of the elastomeric material; and

Fig. 11 is a schematic representation of a lamination device for forming the elastic laminate shown in Fig. 9.

DETAILED DESCRIPTION

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. Herein, "pull-on garment" 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 over the waist. Herein, "disposable" 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). A "unitary" pull- on garment refers to pull-on garments which are formed of separate parts united together to form a coordinated entity, but the ear panels are not separate elements joined to a separate chassis; rather, the ear panels are formed by at least one layer which also forms the chassis of the garment (i.e., the garment does not require separately manipulative panels such as a separate chassis and separate ear panels). The pull-on garment is also preferably "absorbent" to absorb and contain the various exudates discharged from the body. A preferred embodiment of the pull-on garment of the present invention is the unitary disposable absorbent pull-on garment, pull-on garment 120, shown in Fig. 1. Herein, "pull-on diaper" refers to pull-on garments generally worn by infants and other incontinent individuals to absorb and contain urine and feces. It should be understood, however, that the present invention is also applicable to other pull-on garments such as training pants, incontinent briefs, feminine hygiene garments or panties, and the like. Herein, "panel" denotes an area or element of the pull-on garment. (While a panel is typically a distinct area or element, a panel may coincide (functionally correspond) somewhat with an adjacent panel.) Herein, "joined" or "joining" encompasses configurations whereby an element is directly secured to another by affixing the element directly to the other element, and configurations whereby the element is indirectly secured to the other element by affixing the element to intermediate member(s) which in turn are affixed to the other element. Herein, "uncontracted state" is used herein to describe states of pull-on garments in its unseamed (i.e., seams are removed), flat and relaxed condition wherein all elastic materials used are removed therefrom. Fig. 1 shows one preferred embodiment of a disposable pull-on garment of the present invention (i.e., a unitary disposable pull-on diaper 120). Referring to Fig. 1 , the disposable pull-on garment 120 has a front region 26; a back region 28 and a crotch region 30 between the front region 26 and the back region 28. A chassis 41 is provided in the front, back and crotch regions 26, 28 and 30. The chassis 41 includes a liquid pervious topsheet 24, a liquid impervious backsheet 22 associated with the topsheet 24, and an absorbent core 25 (not shown in Fig. 1) disposed between the topsheet 24 and the backsheet 22. The chassis 41 has side edges 220 which form edge lines 222 in the front region 26.

The pull-on garment 120 of the invention further includes at least one pair of extensible ear panels 45 each extending laterally outward from the corresponding sides of the chassis 41. Each of the ear panels 45 has an outermost edge 240 which forms an outermost edge line 242. At least one of the outermost edge lines 242 has a nonuniform lateral distance from the longitudinal center line 100 (not shown in Fig. 1) in the uncontracted state of the garment 120. In a preferred embodiment, the ear panels 45 continuously extend from the corresponding sides of the chassis 41 in the back region 28 to the corresponding side edges 220 of the chassis 41 in the front region 26 as shown in Fig. 1. Alternatively, the ear panels 45 may continuously extend from the corresponding sides of the chassis 41 in the front region 26 to the corresponding side edges of the chassis 41 in the back region 28 (not shown in Fig. 1). The pull-on garment 120 has the ear panels 45 joined to the chassis 41 to form two leg openings 34 and a waist opening 36. Preferably, the pull-on garment

120 further includes seams 232 each joining the chassis 41 and the ear panels 45 along the corresponding edge lines 222 and 242 to form the two leg openings 34 and the waist opening 36.

Fig. 2 shows another preferred embodiment of a disposable pull-on garment of the present invention (i.e., a unitary disposable pull-on diaper 20). Referring to Fig. 2, the disposable pull-on garment 20 includes a pair of extensible front ear panels 46 each extending laterally outward from the corresponding sides of the chassis 41 in the front region 26, and a pair of extensible back ear panels 48 each extending laterally outward from the corresponding sides of the chassis 41 in the back region 28. Each of the ear panels 46 and 48 has an outermost edge 240 which forms an outermost edge line 242. At least one of the outermost edge lines 242 has a nonuniform lateral distance LD from the longitudinal center line 100 (not shown in Fig. 2 but in Fig. 3) in the uncontracted state of the garment 20. The pull- on garment 20 further includes seams 32 each joining the front and back ear panels 46 and 48 along the corresponding edge lines 242 to form the two leg openings 34 and the waist opening 36.

In a preferred embodiment, at least one of, more preferably both of, the pairs of the ear panels 45, 46 and 48 are elastically extensible in at least the lateral direction. In alternative embodiments, the ear panels 45, 46 and 48 are elastically extensible both in the lateral and longitudinal directions. 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 extensible ear panels 45, 46 and 48 provide a more comfortable and contouring fit by initially conformably fitting the pull-on garment to the wearer and sustaining this fit throughout the time of wear well past when the pull-on garment has been loaded with exudates since the ear panels 45, 46 and/or 48 allow the sides of the pull-on garment to expand and contract.

The ear panels 45, 46 and 48 may be formed by unitary elements of the pull-on garment 20 or 120 (i.e., they are not separately manipulative elements secured to the pull-on garment 20 or 120, but rather are formed from and are extensions of one or more of the various layers of the pull-on garment). In a preferred embodiment, each of the ear panels 45, 46 and 48 is a projected member of the chassis 41 (more clearly shown in Fig. 3). Preferably, the ear panels 45, 46 and 48 include at least one unitary element or a continuous sheet material (e.g. the nonwoven outer cover 74 in Fig. 4) that forms a part of the chassis 41 and continuously extends into the ear panels 45, 46 and 48. Alternatively, the ear panels 45, 46 and 48 may be discrete members (not shown in Figs.) which do not have any unitary element that forms a part of the chassis 41 , and may be formed by joining the discrete members to the corresponding sides of the chassis 41. In a preferred embodiment, the pull-on garment 20 or 120 further includes seam panels 66 each extending laterally outward from each of the ear panels 45, 46 and 48; and tear open tabs 31 each extending laterally outward from the seam panel 66. In a preferred embodiment, each of the seam panels 66 is an extension of the corresponding ear panels 45, 46 and 48, or at least one of the component elements used therein, or any other combination of the elements. More preferably, each of the tear open tabs 31 is also an extension of the corresponding seam panel 66 or at least one of its component elements used therein, or any other combination of its elements.

In a preferred embodiment, the corresponding edge portions of the chassis 41 and/or the ear panels 45, 46 and 48 are seamed directly or indirectly (e.g., through the seam panels 66), in an overlaping manner to make an overlapped seam structure. Alternatively, the front and ear panels 46 and 48 can be seamed in a butt seam manner (not shown in Figs.). The bonding of the seams 32 can be performed by any suitable means known in the art appropriate for the specific materials employed in the chassis 41 and/or the ear panels 45, 46 and 48. Thus, sonic sealing, heat sealing, pressure bonding, adhesive or cohesive bonding, sewing, autogeneous bonding, and the like may be appropriate techniques. Preferably, the seam panels 66 are joined by a predetermined pattern of heat/pressure or ultrasonic welds which withstands the forces and stresses generated on the garment 20 or 120 during wear.

A continuous belt 38 is formed by the ear panels 45, 46 and 48, and a part of the chassis 41 about the waist opening 36 as shown in Figs. 1 and 2. Preferably, elasticized waist bands 50 are provided in both the front region 26 and the back region 28. The continuous belt 38 acts to dynamically create fitment forces in the pull-on garment 20 or 120 when positioned on the wearer, to maintain the pull-on garment 20 or 120 on the wearer even when loaded with body exudates thus keeping the absorbent core 25 (not shown in Fig. 2) in close proximity to the wearer, and to distribute the forces dynamically generated during wear about the waist thereby providing supplemental support for the absorbent core 25 without binding or bunching the absorbent core 25.

Fig. 3 is a partially cut-away plan view of the pull-on garment 20 of Fig. 2 in its uncontracted state (except in the ear panels 46 and 48 which are left in their relaxed condition) with the topsheet 24 facing the viewer, prior to the ear panels 46 and 48 being joined together by the seams 32. The pull-on garment 20 has the front region 26, the back region 28 opposed to the front region 26, the crotch region 30 positioned between the front region 26 and the back region 28, and a periphery which is defined by the outer perimeter or edges of the pull-on garment 20 in which the side edges are designated 150 and 240, and the end edges or waist edges are designated 152. The topsheet 24 has the body-facing surface of the pull-on garment 20 which is positioned adjacent to the wearer's body during use. The backsheet 22 has the outer-facing surface of the pull-on garment 20 which is positioned away from the wearer's body. The pull-on garment 20 includes the chassis 41 including the liquid pervious topsheet 24, the liquid impervious backsheet 22 associated with the topsheet 24, and the absorbent core 25 positioned between the topsheet 24 and the backsheet 22. The garment 20 further includes the front and back ear panels 46 and 48 extending laterally outward from the chassis 41, the elasticized leg cuffs 52, and the elasticized waistbands 50. The topsheet 24 and the backsheet 22 have length and width dimensions generally larger than those of the absorbent core 25. The topsheet 24 and the backsheet 22 extend beyond the edges of the absorbent core 25 to thereby form the side edges 150 and the waist edges 152 of the garment 20. The liquid impervious backsheet 22 preferably includes a liquid impervious plastic film 68.

The pull-on garment 20 also has two centerlines, a longitudinal centerline 100 and a transverse centerline 110. Herein, "longitudinal" refers to a line, axis, or direction in the plane of the pull-on garment 20 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 pull-on garment 20 is worn. Herein, "transverse" and "lateral" are interchangeable and refer to a line, axis or direction which lies within the plane of the pull-on garment that is generally perpendicular to the longitudinal direction (which divides the wearer into front and back body halves). The pull-on garment 20 and component materials thereof also have a body-facing surface which faces the skin of wearer in use and an outer-facing surface which is the opposite surface to the body-facing surface.

Each of the ear panels 45, 46 and 48 has the outermost edge line 242. Herein, "edge line" refers to lines which define the outlines of the ear panels 45, 46 and 48 or the chassis 41. Herein, "outermost" refers to portions which are farthest from the longitudinal centerline 100. At least one of the edge lines 242 has a nonuniform lateral distance LD from the longitudinal center line 100 in the uncontracted state of the garment 20. While the topsheet 24, the backsheet 22, and the absorbent core 25 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 Kenneth B. 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 Kenneth B. Buell et al., on September 29, 1992.

Fig. 4 is a cross-sectional view of a preferred embodiment taken along the section line 4-4 of Fig. 3. The pull-on garment 20 includes the chassis 41 including the liquid pervious topsheet 24, the liquid impervious backsheet 22 associated with the topsheet 24, and the absorbent core 25 positioned between the topsheet 24 and the backsheet 22. The pull-on garment further includes the front ear panels 46 each extending laterally outward from the chassis 41 , and an inner barrier cuffs 54. Although Fig. 4 depicts only the structure of the front ear panel 46 and the chassis 41 in the front region 26, preferably a similar structure is also provided in the back region 28. In a preferred embodiment, each of the front ear panels 46 is formed by a lamination of an extended part 72 of the barrier flap 56, an elastic laminate 70 and the nonwoven outer cover 74. The elastic laminate 70 includes a plane elastomeric material 124 (not shown in Fig. 4 but in Fig. 6). 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 124 includes at least a portion that has a nonuniform lateral width.

The absorbent core 25 can 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 25 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.

The configuration and construction of the absorbent core 25 may vary (e.g., the absorbent core 25 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). Further, the size and absorbent capacity of the absorbent core 25 may also be varied to accommodate wearers ranging from infants through adults. However, the total absorbent capacity of the absorbent core 25 should be compatible with the design loading and the intended use of the garment 20. A preferred embodiment of the garment 20 has an asymmetric, modified hourglass-shaped absorbent core 25 having ears in the front and back waist regions 26 and 28. Other exemplary absorbent structures for use as the absorbent core 25 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 chassis 41 may further include an acquisition/distribution core 84 of chemically stiffened fibers positioned over the absorbent core 25, 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 84 can also be stiffened by means of chemical reaction. For example, crosslinking agents can be applied to the fibers which, subsequent to application, are caused to chemically form intrafiber crosslink bonds. These crosslink bonds can increase 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 stiffened 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 can 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 the 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. The 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, LaVon and Taylor on September 15, 1992. In a preferred embodiment, the acquisition/distribution core 84 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 84 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.

More preferably, the chassis 22 further includes an acquisition/distribution layer 82 between the topsheet 24 and the acquisition/distribution core 84 as shown in Fig. 4. The acquisition/distribution layer 82 is provided to help reduce the tendency for surface wetness of the topsheet 24. The acquisition/distribution layer 82 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 telephthalate fibers of 6 dtex, and has a basis weight of about 43 g/m2. A preferable example for the acquisition/distribution layer 82 and the acquisition/distribution core 84 is disclosed in EP 0797968A1 (Kurt et al.) published on October 1 , 1997.

The topsheet 24 is preferably compliant, soft feeling, and non-irritating to the wearer's skin. Further, the topsheet 24 is liquid pervious permitting liquids (e.g., urine) to readily penetrate through its thickness. A suitable topsheet 24 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 can be included of natural fibers (e.g., wool or cotton fibers), synthetic fibers (e.g., polymeric fibers such as polyester, polypropylene, or polyethylene fibers) or from a combination of natural and synthetic fibers. The topsheet 24 is preferably made of a hydrophobic material to isolate the wearer's skin from liquids which have passed through the topsheet 24 and are contained in the absorbent core 25 (i.e., to prevent rewet). If the topsheet 24 is made of a hydrophobic material, at least the upper surface of the topsheet 24 is 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 24 rather than being drawn through the topsheet 24 and being absorbed by the absorbent core 25. The topsheet 24 can be rendered hydrophilic by treating it with a surfactant. Suitable methods for treating the topsheet 24 with a surfactant include spraying the topsheet 24 material with the surfactant and immersing the material 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 24 is a nonwoven web that can provide reduced tendency for surface wetness; and consequently facilitate maintaining urine absorbed by the core 25 away from the user's skin, after wetting. One of the preferred topsheet materials 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., 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 24 includes an apertured formed film. Apertured formed films are preferred for the topsheet 24 because they 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. 5,006,394 "Multilayer Polymeric Film" issued to Baird on April 9, 1991.

In a preferred embodiment, the backsheet 22 includes the liquid impervious film 68 as shown in, for example, Fig. 4. Preferably, the liquid impervious film 68 longitudinally extends in the front, back and crotch regions 26, 28 and 30. More preferably, the liquid impervious film 68 does not laterally extend into the at least one of the ear panels 46 or 48. The liquid impervious film 68 has a body-facing surface 79 and an outer-facing surface 77. The liquid impervious film 68 is impervious to liquids (e.g., urine) and is preferably manufactured from a thin plastic film. However, more preferably the plastic film permits vapors to escape from the garment 20. In a preferred embodiment, a microporous polyethylene film is used for the liquid impervious film 68. A suitable microporous polyethylene film is manufactured by Mitsui Toatsu Chemicals, Inc., Nagoya, Japan and marketed in the trade as PG-P. In a preferred embodiment, a disposable tape (not shown in Figs.) is additionally joined to the outer surface of the backsheet 22 to provide a convenient disposal after soiling.

A suitable material for the liquid impervious film 68 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/m2 to about 35 g/m2. 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.

Preferably, the backsheet 22 further includes the nonwoven outer cover 74 which is joined with the outer-facing surface of the liquid impervious film 68 to form a laminate (i.e., the backsheet 22). The nonwoven outer cover 74 is positioned at the outermost portion of the garment 20 and covers at least a portion of the outermost portion of the garment 20. In a preferred embodiment, the nonwoven outer cover 74 covers almost all of the area of the outermost portion of the garment 20. The nonwoven outer cover 74 may be joined to the liquid impervious film 68 by any suitable attachment means known in the art. For example, the nonwoven outer cover 74 may be secured to the liquid impervious film 68 by a uniform continuous layer of adhesive, a patterned layer of adhesive, 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.

In a preferred embodiment, the nonwoven outer cover 74 is a carded nonwoven web, for example, obtainable from Havix Co., LTD., Gifu, Japan as E- 2341. The nonwoven outer cover 74 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. The nonwoven outer cover 74 is also made of bi-component fibers of a polyethylene (PE) and a polypropylene (PP). The ratio of PE/PP is 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 a polyethylene (PE) and a polypropylene (PP). The ratio of PE/PP is about 80/20. The PE/PP bi-component fiber has the thickness is approximately 2.3d. Another spunbonded nonwoven web is obtainable from Fiberweb France S.A., under Code No. 13561 DAPP.

The backsheet 22 is preferably positioned adjacent the outer-facing surface of the absorbent core 25 and is preferably joined thereto by any suitable attachment means known in the art. For example, the backsheet 22 may be secured to the absorbent core 25 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, Jr. 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 an alternative embodiment, the absorbent core 25 is not joined to the backsheet 22, and/or the topsheet 24 in order to provide greater extensibility in the front region 26 and the back region 28.

The pull-on garment 20 preferably further includes elasticized leg cuffs 52 for providing improved containment of liquids and other body exudates. The elasticized leg cuffs 52 may include several different embodiments for reducing the leakage of body exudates in the leg regions. (The leg cuffs can be and are sometimes also referred to as leg bands, side flaps, barrier cuffs, elastic cuffs or gasketing cuffs.) U.S. Patent 3,860,003 entitled "Contractable Side Portions for Disposable Diaper" issued to Buell on January 14, 1975, 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 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 4,695,278 entitled "Absorbent Article Having Dual Cuffs" issued to Lawson on September 22, 1987; and U.S. Patent 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 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 garment.

While each elasticized leg cuff 52 may be configured so as to be similar to any of the leg bands, side flaps, barrier cuffs, or elastic cuffs described above, it is preferred that the elasticized leg cuff 52 includes an elastic gasketing cuff 62 with one or more elastic strands 64 as shown in Fig. 3, which is described in the above- referred U.S. Patent Nos. 4,695,278 and 4,795,454. It is also preferred that each elasticized leg cuff 52 further includes inner barrier cuffs 54 each including a barrier flap 56 and a spacing means 58 which are described in the above-referenced U.S. Patent No. 4,909,803. The pull-on garment 20 of the present invention further includes an elasticized waistband 50 that provides improved fit and containment. The elasticized waistband 50 is that portion or zone of the pull-on garment 20 which is intended to elastically expand and contract to dynamically fit the wearer's waist. The waistband 50 of the present invention includes an elastic laminate 70 which will be described in detail hereinafter. The waistband 50 is disposed along at least one, preferably both of the end edges 152 of the disposable garment 20. The elasticized waistband 50 preferably extends longitudinally inwardly from the end edge 152 of the pull-on garment 20 toward the waist edge 154 of the absorbent core 25. Preferably, the pull-on garment 20 has two elasticized waistbands 50, one positioned in the back region 28 and one positioned in the front region 26, although other pull-on diaper embodiments can be constructed with a single elasticized waistband. The elasticized waistband 50 may be constructed in a number of different configurations including those described in U.S. Patent 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 5,151 ,092 issued to Buell. Fig. 5 is a cross-sectional view of one preferred embodiment taken along the section line 5-5 of Fig. 3. As shown in Fig. 5, both the backsheet 22 and the topsheet 24 extend beyond the waist edge 154 of the absorbent core 25 to define a waist flap 156. Preferably, the juxtaposed areas of the backsheet 22 and the topsheet 24 are joined together by an adhesive (not shown in Figs.). In a preferred embodiment, the waistband 50 is joined to the waist flap 156. Preferably, the waistband 50 is disposed on and joined to the topsheet 24 as shown in Fig. 5. Alternatively, the waistband 50 can be disposed and joined between the backsheet 22 and the topsheet 24 as shown in Fig. 6. The waistband 50 can be joined to the topsheet 24 (and the backsheet 22) by an adhesive means (not shown in Figs.) such as those well known in the art. For example, the waistband 50 may be secured to the waist flap 156 by a uniform continuous layer of adhesive, a patterned layer of adhesive, or an array of separate lines or spots of adhesive. A preferred adhesive for use is available from Ato Findley Inc., Wl, U.S.A., under the designation H2085.

In a preferred embodiment, the waistband 50 is secured to the waist flap 156 in an elastically contractible condition so that in a normally unrestrained configuration the waistband 50 effectively contract or gather the waist flap 156. The waistband 50 can be secured to the waist flap 156 in an elastically contractible condition in at least two ways. For example, the waistband 50 may be stretched and secured to the waist flap 156 while the waist flap 156 is in an uncontracted condition. Alternatively, the waist flap 156 may be contracted, for example by pleating, and the waistband 50 is secured to the contracted waist flap 156 while the waistband 50 in its relaxed or unstretched condition. Yet alternatively, the waistband 50 is joined, in its relaxed or unstretched condition, to the waist flap 156 which is in an uncontracted condition, thereby forming a composite laminate with the materials of the backsheet 22 and the topsheet 24. At least a portion, preferably the entire portion of the composite laminate is then subjected to mechanical stretching sufficient to permanently elongate the non-elastic components which are the backsheet 22 and the topsheet 24. The composite laminate is then allowed to return to its substantially untensioned condition. Thus, the composite laminate is formed into a "zero strain" stretch laminate which works as elasticized waistband 50.

Herein, "zero strain" stretch laminate refers to a laminate included of 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 a preferred embodiment, the waistband 50 extends across essentially the entire lateral width of the absorbent core 25. Herein, "lateral width" refers to the dimension between the side edges of components of disposable garments. Herein, "across essentially" is used in this context to indicate that the waistband 50 does not need to extend absolutely across the entire width of the absorbent core 25 so long as it extends sufficiently far across the width thereof to provide the elasticized waistband. Preferably, the waistband 50 extends across only a portion of the lateral width of the absorbent core 25, more preferably at least between portions in the ear panels 46 and 48 (as shown in Fig. 3). In one preferred embodiment, the waistband 50 extends across the entire lateral width of the garment 20 (not shown Figs.).

The extent to which the waistband 50 extends inboard from the end edge 152 of the garment 20, and thus the longitudinal span of the resultant waistband, can vary according to the particular construction of the garment 20. The longitudinal span of the waistband 50 is at least about 5 mm, preferably from about 6 mm to about 60 mm, more preferably from about 15 mm to about 30 mm. At least one of the ear panels 45, 46 and 48 includes the elastic laminate 70 of the present invention. For example, each of the front ear panels 46 shown in Fig. 4 includes the elastic laminate 70 which includes the elastomeric material 124 (not shown in Fig. 4) which preferably extends laterally outward from the chassis 41 to provide good fitness by generating the optimal retention (or sustained) force at the waist and side areas of the wearer. Preferably, the elastomeric material 124 is extensible in at least one direction, preferably in the lateral direction to generate a retention (or sustained) force that is optimal to prevent the pull-on garment 20 from drooping, sagging, or sliding down from its position on the torso without causing the red marking on the skin of the wearer. In a preferred embodiment, each of the ear panels 45, 46 and 48 includes the elastomeric material 124.

The elastic laminate 70 is operatively joined to at least one of the nonwoven webs 72 and 74 in the ear panels 45, 46 and 48 to allow the elastic laminate 70 to be elastically extensible in at least the lateral direction. In a preferred embodiment, the elastic laminate 70 is operatively joined to the nonwoven webs 72 and 74 by securing them to at least one, preferably both of the nonwoven webs 72 and 74 while in a substantially untensioned (zero strain) condition.

The elastic laminate 70 can be operatively joined to the nonwoven webs 72 and 74, 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 webs 72 and 74) 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 panel members 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/square m. The adhesive pattern width is about 6.0 cm. The adhesive is preferably an adhesive such as is available from Nitta Findley Co., Ltd., Osaka, Japan, under the designation H2085F. Alternatively, the elastic panel 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.

After the elastic laminate 70 is operatively joined to at least one of the nonwoven webs 72 and 74, at least a portion of the resultant composite stretch laminate is then subjected to mechanical stretching sufficient to permanently elongate the non-elastic components which are, for example, the nonwoven webs 72 and 74. The composite stretch laminate is then allowed to return to its substantially untensioned condition. At least one pair of, preferably both of the ear panels 45, 46 and 48 is thus formed into "zero strain" stretch laminates. (Alternatively, the elastic laminate 70 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.)

The elastic laminate 70 is preferably joined to, more preferably directly secured to the respective edges 78 of the liquid impervious film (i.e., the liquid impervious film 68) through an adhesive 76 as shown in Fig. 4. In a preferred embodiment, while liquid impervious film 68 longitudinally extends in the front, back and crotch regions 26, 28 and 30, it does not laterally extend into at least one of, preferably each of the extensible ear panels 45, 46 and 48. In a more preferred embodiment, the elastic laminate 70 is joined to the respective edges 78 of the liquid impervious film 68 at the outer-facing surface 77 as shown in Fig. 4. In an alternative embodiment, the elastic laminate 70 may be joined to the respective edges 78 of the liquid impervious film 68 at the body-facing surface 79 (not shown in Figs.). Preferably, the adhesive 76 is applied in a spiral glue pattern. In a preferred embodiment, the adhesive 76 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 laminate 70 may be joined to the respective edges 78 of the liquid impervious film 68 by any other bonding means known in the art which include heat bonds, pressure bonds, ultrasonic bonds, dynamic mechanical bonds, or combinations of these attachment means. Fig. 8 is a fragmentary enlarged perspective view of an elastic laminate 70 of one preferred embodiment, prior to being formed into the elastic laminate. (One preferred embodiment of the elastic laminate 70 after the formation is shown in Fig. 9.) Referring to Fig. 8, the elastic laminate 70 of the present invention includes an elastomeric layer 124 having a first surface 150 and a second surface 152 opposing the first surface 150; and a first nonwoven layer 122 which is joined to the first surface 150 of the elastomeric layer 124. In a preferred embodiment, the first surface 150 and second surface 152 of the elastomeric layer 124 are substantially parallel with the plane of the first nonwoven layer 122. The first nonwoven layer 122 has an inner surface (or a first surface) 142 and an outer surface (or a second surface) 144. The inner surface 142 of the first nonwoven layer 122 is the surface that is positioned facing the elastomeric layer 124.

In a preferred embodiment, the elastic laminate 70 further comprises a second nonwoven layer 126 joined to the second surface 152 of the elastic material 70. The second nonwoven layer 126 also has an inner surface 146 and an outer surface 148. The inner surface 146 of the second nonwoven layer 126 is the surface that is positioned facing the elastomeric layer 124. The second surface 152 of the elastomeric layer 124 is substantially parallel with the plane of the second nonwoven layer 126. In a preferred embodiment, the nonwoven layer 126 is formed by an identical nonwoven material with that is employed in the first nonwoven layer 122. Alternatively, the nonwoven layer 126 may be formed by a different material from that is employed in the first nonwoven layer 122.

The elastic laminate 70 of the present invention is elastically extensible in at least one direction (first direction). For example, the elastic laminate 70 shown in Fig. 8 is elastically extensible in the structural direction D. Herein, "structural direction" (e.g., D and B) is intended to mean a direction which extends substantially along and parallel to the plane of the first nonwoven layer 122. In a preferred embodiment, the elastic laminate 70 is also elastically extensible in the second direction which is perpendicular to the first direction. For example, the elastic laminate 70 shown in Fig. 8 is also elastically extensible in the structural direction B.

The first nonwoven layer 122 of the present invention may be manufactured from a wide range of component fibers which are formed from a polyester. Preferred polyester materials includes a polyethylene terephthalate, a polybutylene terephthalate and a polypropylene terephthalate, or mixtures thereof. In a preferred embodiment, the first nonwoven layer 122 additionally includes component fibers formed from the other materials (i.e., non-polyester materials) such as polyolefin and nylon.

In a preferred embodiment, the individual component fibers are formed from a single type of material which is selected from the above materials (i.e., the individual fiber is not made from polyolefin and nylon). Preferably, the component fibers are formed from a polyester, more preferably a polyethylene terepthalate, or one of its relatives which has an average molecular weight from about 5,000 to about 60,000, preferably from about 10,000 to about 40,000, more preferably from about 14,000 to about 23,000. Alternatively, the component fibers may be formed from a mixture of two (or more) materials which are selected from the above materials.

In one embodiment, the component fiber has a bi-component fiber structure formed from two distinct materials of a polyester and a polyolefin. In an alternative embodiment, the component fiber has a bi-component fiber structure formed from two distinct molecular weight materials of one identical material, for example, a polyester. Preferred bi-component fiber structures may include a side-by-side bi- component fiber structure and a sheath-core bi-component fiber structure known in the art. In one embodiment, the component fiber has a bi-component fiber structure having a core of polyolefin and a sheath of a polyester.

In a preferred embodiment, the first nonwoven layer 122 has a basis weight of less than about 60 g/m2, and comprises fibers having a fiber diameter of less than about 50 μm. More preferably, for products such as disposable garment and the like, the first nonwoven layer 122 has a basis weight of from about 3 g/m2 to about 50 g/m2, more preferably from about 10 g/m2 to about 25 g/m2, and a fiber diameter of from about 1 μm to about 30 μm, more preferably from about 3 μm to about 20 μm.

The component fibers may be joined together by adhesives, thermal bonding, water-jetting, needling/felting, or other methods known in the art to form nonwoven fabrics. In a preferred embodiment, the first nonwoven layer 122 is formed from a nonwoven manufacturing process handling continuous component fibers or filaments known in the art. Preferred manufacturing process are described in, for example, EP 0843036A1 (Kurihara et al.) published on May 20, 1998; U.S. Patent No. 5,312,500, entitled "Non-Woven Fabric and Method and Apparatus for Making The Same", issued to Kurihara et al. on May 17, 1994; Japanese Laid-Open Patent Publication (Kokai) No. H2-269859 published on November 5, 1990; and Japanese Patent Publication (Kokoku) No. S60-25541 published on June 19, 1985.

In a preferred embodiment, the first nonwoven layer 122 is formed from component fibers which are joined together. The component fibers have a primary fiber direction. The first nonwoven layer 122 has a Fiber Orientation Ratio within about ±20 degrees from the primary fiber direction (FOR20) of at least about 65%; more oreferably at least about 75%; more preferably still at least about 85%. In a more preferred embodiment, the first nonwoven layer 122 additionally has a Fiber Orientation Ratio within about ±10 degrees from the primary fiber direction (FOR10) of at least about 45%; more preferably at least about 60%; more preferably still at least about 70%.

"FOR#" (e.g., FOR10) indicates the ratio of the number of the component fibers whose directions are within about ±# degrees, (e.g., ±10 degrees) from the primary fiber direction to the total number of component fibers. Herein, "primary fiber direction" refers to an average direction of component fibers in the nonwoven layer. One preferred method for measuring the Fiber Orientation Ratio of nonwoven layers is explained in more detail below.

In a more preferred embodiment, the first nonwoven layer 122 has a Tensile Strength Ratio (TSR) of at least about 15, more preferably at least about 60. The TSR is defined by the following calculation:

TSR = TS1 / TS2 (1) wherein,

TS1 (gf/inch): a tensile strength (TS) at the breaking point in the primary fiber direction; and

TS2 (gf/inch): a tensile strength (TS) at the breaking point in the perpendicular direction which is perpendicular to the primary fiber direction.

Tensile Strength (ST) is measured as the maximum tensile strength value recorded while the first nonwoven layer 122 is stretched at a rate of about 20 inches/min (about 50 cm/min) to its breaking point. The tensile strength of the first nonwoven layer 122 is measured before the first nonwoven layer 122 is joined to the elastomeric layer 124.

In a preferred embodiment, the first nonwoven layer 122 has a tensile strength of less than about 200 gf/inch (about 80 gf/cm) at 30% elongation to the direction which is perpendicular to the primary fiber direction; more preferably less than about 100 gf/inch (about 40 gf/cm), more preferably still less than about 50 gf/inch (about 20 gf/cm).

Preferred nonwoven fabrics which are suitably applicable to the first nonwoven layer 122 are available from Nippon Petrochemicals Co., Ltd., Tokyo, Japan, under Code Nos. MBE7711-2; MBE6515-10; and MBE7922-1 which have the following properties.

Table

The elastomeric layer 124 may be formed in a wide variety of sizes, forms and shapes. In a preferred embodiment, the elastomeric layer 124 is in the form of a continuous plane layer such as shown in, for example, Fig. 8. Preferred forms of a continuous plane layer include a scrim, a perforated (or apertures formed) film, an elastomeric woven or nonwoven, and the like. Preferably, the elastomeric layer 124 has a thickness of from about 0.05 mm to about 1 mm (about 0.002 inch - about 0.039 inch). The continuous plane layer may take any shape which can be suitably provided in products. Preferred shapes of a continuous plane layer include a quadrilateral including a rectangle and a square, a trapezoid, and the other polygons. In an alternative embodiment, the elastomeric layer 124 is in the form of discrete strands (or strings) which are not connected each other. Preferred elastomeric materials of the present invention include diblock and triblock copolymers based on polystyrene and unsaturated or fully hydrogenerated rubber bolcks, and their blends with other polymers such as polyolefin polymers.

Preferably, the polystyrene thermoplastic elastomer is selected from the group consisting of a styrene-butadiene-styrene thermoplastic elastomer, a styrene-isopren-styrene thermoplastic elastomer, a styrene-ethylene/butylene- styrene thermoplastic elastomer, a styrene-ethylene/propylene-styrene thermoplastic elastomer, a styrene-ethylene/propylene thermoplastic elastomer, a hydrogenated styrene butadiene rubber, and a mixture thereof. A preferred styrenic block copolymer based material contains from about 1 wt% to about 70 wt% of polystyrene, more preferably from about 10 wt% to about 50 wt% of polystyrene.

In an alternative preferred embodiment, the elastomeric material 124 is a porous, macroscopically-expanded, three-dimensional elastomeric web 172 as shown in Fig. 10. The web 172 has a continuous first surface 174 and a discontinuous second surface 176 opposing to the first surface 174. The elastomeric web 172 preferably comprises a formed film interconnecting member 186 including at least two polymeric layers 178 and 182. The first layer 178 is substantially elastic and the second layer 182 is substantially less elastic than the first layer 178. At least one of the two polymeric layers 178 and 182 is formed from a polystyrene thermoplastic elastomer. The elastomeric web 172 exhibits a multiplicity of primary apertures 184 in the first surface 174 of the web 172. The primary apertures 184 are defined in the plane of the first surface 174 by a continuous network of the interconnecting member 186. The interconnecting member 186 exhibits an upwardly concave-shaped cross-section along its length. The interconnecting member 186 also forms secondary apertures 188 in the plane of the second surface 176 of the web 172. The apertures 184 and 188 may take any shape. A preferred elastomeric web is disclosed in U.S. Patent application serial number 08/816,106, filed on March 14, 1997. A preferred porous elastomeric material for the elastomeric layer 124 is available from Tredegar Film Products under the designation X-25007.

The extension properties of the elastomeric material 124 such as the First Cycle Extension Force at 100% Extension (FCEF100%), the First Cycle Extension Force at 200% Extension (FCEF200%), the Second Cycle Recovery Force at 50% Extension (SCRF50%) and sustained load at 50 % after 10 - 12 hours are important considerations in the performance of disposable garments. The elastomeric material 124 preferably has extension properties within the defined ranges described hereinafter. In a preferred embodiment, the FCEF100% of the elastomeric material 124 is at least about 100 gf/inch. More preferably, the FCEF100% is between about 120 to about 220 gf/inch, most preferably between about 150 gf/inch and 190 gf/inch. The FCEF200% is preferably between about 160 gf/inch and about 450 gf/inch, more preferably between about 180 gf/inch and about 300 gf/inch, and yet more preferably between about 200 gf/inch and about 240 gf/inch. The SCRF50% of the elastomeric material 124 is preferably between about 40 gf/inch and about 130 gf/inch, more preferably between about 65 gf/inch and about 105 gf/inch, and yet more preferably between about 75 gf/inch and about 95 gf/inch. The sustained load at 50 % after 10 - 12 hours is preferably between about 40 gf/inch and about 130 gf/inch, more preferably between about 65 gf/inch and about 105 gf/inch, and yet more preferably between about 75 gf/inch and about 95 gf/inch.

The values of FCEF100%, FCEF200% and SCRF50% can be measured by using a tensile tester. The tensile tester includes an upper jaw and a lower jaw which is located below the upper jaw. The upper jaw is movable and is connected to an extension force measuring means. The lower jaw is fixed in the tester. A test specimen (i.e., the elastomeric material to be measured) which has about 2.5 cm (about 1 inch) in width and about 12.8 cm (about 5 inches) in length is prepared and clamped between the upper jaw and the lower jaw so that the effective specimen length (L) (i.e., gauge length) is about 5.1 cm (about 2 inches). The extension force is applied to the test specimen through the upper jaw. When no extension force is applied to the test specimen, the test specimen is in its original length (i.e., 0% extension). A tensile tester suitable for use herein is available from Instron Corporation (100 Royall Street, Canton, MA02021 , U.S.A.) as Code No. Instron 5564. Fig. 7 shows one preferred example of the extension and recovery force curves for the two cycle hysteresis of the elastomeric material 124. The curve E1 shows the extension force in the first cycle, while the curve R1 shows the recovery force in the first cycle. The curve E2 (shown in dashed lines) shows the extension force in the second cycle, while the curve R2 shows the recovery force in the second cycle. The extension and recovery properties are measured as follows.

In the first cycle, the test specimen is subjected to an initial extension force at a crosshead rate of about 51 cm/min (about 20 in/min) at about 23°C and held for about 30 seconds at 200% extension. The test specimen is then allowed to relax at the same rate to the original state (i.e., 0% extension). The test specimen is allowed to remain unconstrained for one minute before being subjected to a second extension force (for the second cycle) at the same rate and conditions.

In one preferred embodiment, the elastomeric layer 124 is in the form of a scrim 130 as shown in Fig. 8. The elastomeric scrim 130 comprises a plurality of first strands 125 which intersect or cross (with or without bonding to) a plurality of second strands 127 at nodes 128 at a predetermined angle α, thereby forming a net-like open structure having a plurality of apertures 132. Each aperture 132 is defined by at least two adjacent first strands 125 and at least two adjacent second strands 127 such that apertures 132 are substantially rectangular (preferably square) in shape. Other aperture configurations, such as parallelograms or circular arc segments, can also be provided. Such configurations could be useful for providing non-linear elastic structural directions. Preferably, the first strands 125 are substantially straight and substantially parallel to one another; and, more preferably, the second strands 127 are also substantially straight and substantially parallel to one another. More preferably, first strands 125 intersect second strands 127 at nodes 128 at a predetermined angle α of about 90 degrees. Each node 128 is an overiaid node, wherein first strands 125 and second strands 127 are preferably joined or bonded (although it is contemplated that joining or bonding may not be required) at the point of intersection with the strands still individually distinguishable at the nodes 128. However, it is believed that other node configurations such as merged or a combination of merged and overlaid would be equally suitable.

Although it is preferred that first and second strands 125 and 127 be substantially straight, parallel, and intersect at an angle α of about 90 degrees, it is noted that first and second strands 125 and 127 can intersect at other angles α, and that first strands 125 and/or second strands 127 can be aligned in circular, elliptical or otherwise nonlinear patterns relative to one another. Although for ease of manufacture it is contemplated that first strands 125 and second strands 127 have a substantially circular cross-sectional shape prior to incorporation into elastic laminate 70 (as shown in Fig. 8), the first and second strands 125 and 127 can also have other cross-sectional shapes such as elliptical, square, triangular or combinations thereof.

Preferably, the material for the first strands 125 is chosen so that the first strands 125 can maintain the second strands 127 in relative alignment prior to forming elastic laminate 70. It is also desirable that the materials for the first and second strands 125 and 127 are capable of being deformed (or initially formed) into predetermined shapes upon application of a predetermined pressure or a pressure in combination with a heat flux prior to forming elastic laminate 70. These deformed shapes (e.g., elliptical second strands, substantially flat first strands and the like) can provide an elastic laminate 70 which can be comfortably worn about the body without irritation or other discomfort. In a preferred embodiment, the first and second strands 125 and 127 are formed from an identical elastomeric material. For example, the first and second strands 125 and 127 are formed from an identical polystyrene thermoplastic elastomer which is selected from the group consisting of a styrene-butadiene- styrene thermoplastic elastomer, a styrene-isopren-styrene thermoplastic elastomer, a styrene-ethylene/butylene-styrene thermoplastic elastomer, a styrene- ethylene/propylene-styrene thermoplastic elastomer, a styrene-ethylene/propylene thermoplastic elastomer, a hydrogenated styrene butadiene rubber or an unsaturated styrene butadiene rubber, and a mixture thereof. A preferred elastomeric scrim 124 which containes a styrene-butadiene-styrene thermoplastic elastomer 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 (about 5 strands/cm) in the structural direction B (i.e., the first strands 125) and about 7 elastic strands per inch (about 3 strands/cm) in the structural direction D (i.e., the second strands 127) before lamination.

Alternatively, the first and second strands 125 and 127 are formed from two different material. For example, one of the first and second strands 125 and 127 is formed from one of the above described polystyrene thermoplastic elastomer, while the other of the first and second strands 125 and 127 is formed from material(s) other than the above described polystyrene thermoplastic elastomer. Such other material(s) may be either elastic or non-elastic, and selected from suitable materials known in the art.

The first nonwoven layer 122 of the present invention is bonded to the first surface 150 of the elastomeric layer 124 by forming a heat/pressure bond between the first nonwoven layer 122 and the elastomeric layer 124. Herein, "heat/pressure bond" is either a physical or chemical bond formed by an application of appropriate heat and pressure to two different members so that the two members can have a portion which has an increased peel strength by the formation of the bond. Herein, "peel strength" refers to the amount of force required to separate the two members from each other. Higher peel strengths typically equate to less chance of de-

/nination of the elastic laminates in use of products. To form such heat/pressure ond(s) between the first nonwoven layer 122 and the elastomeric layer 124, any pressure can be applied to the first nonwoven layer 122 and the elastomeric layer

124 at a certain temperature as long as it does not substantially damage the physical and/or chemical properties of the resulting elastic laminate. Fig. 9 is a partial perspective view of an elastic laminate 70 of yet another embodiment, wherein a portion of the first nonwoven layer 122 has been removed to show the heat/pressure bond structure. In Fig. 9, the elastomeric scrim 130 which is formed by the first and second strands 125 and 127 is used as an example for the elastomeric layer 124. Referring to Fig. 9, the first nonwoven layer 122 is bonded to the first surface 150 of the elastomeric layer 124 by forming a heat/pressure bond between the first nonwoven layer 122 and the elastomeric layer 124. In a preferred embodiment, the elastic laminate further includes a second nonwoven layer (not shown in Fig. 9) which is bonded to the second surface 152 of the elastomeric layer 124 by forming another heat/pressure bond therebetween.

The heat/pressure bond is formed by softening only the material of the elastomeric layer 124 (i.e., without melting the component fibers of the first nonwoven layer 122). This heat/pressure bond is preferably formed by application of a bonding temperature which is lower than the melting point of the material of the first nonwoven layer 122. This generally results in a decrease in the viscosity of the material which may or may not involve a "melting" of the material. As a result, the component materials of the elastomeric layer 124 are softened to form the heat/pressure bond. In a more preferred embodiment wherein the elastomeric layer 124 is formed from a polystyrene thermoplastic elastomer including a polystyrene segment, a bonding temperature which is higher than the glass transition temperature of the polystyrene segment is applied for forming the heat/pressure bond.

Fig. 11 shows one preferred example of a lamination device for forming the elastic laminate 70 shown in Fig. 9. Referring to Fig. 11, the lamination device 800 includes a first pressure plate 801 having a first surface 803, and a second plate 802 having a second surface 804. The second pressure plate 802 is fixed, while the first pressure plate 801 is movable to apply a pressure P to the first nonwoven layer 122 and the elastomeric layer 124 in cooperation with the second pressure plate 802. Preferably, the first and second surfaces 803 and 804 are substantially plane and are substantially parallel each other. The first nonwoven layer 122 is juxtaposed with the elastomeric layer 124 such that the first nonwoven layer 122 is immediately adjacent the elastomeric layer 124. The juxtaposed two layers 122 and 124 are manually supplied to the lamination device 800. A preferred lamination device 800 is available from Toyo Tester Industry Co., Ltd., Osaka, Japan, under a trade name "Heat Sealer".

In the lamination process, the first surface 803 is heated to a temperature T1 , while the second surface 804 is heated to a temperature T2. Preferably, the temperature T1 is from about 80°C to about 160°C, more preferably from about 100°C to about 130°C. The temperature T2 is preferably from about 30°C to about 60°C, more preferably from about 45°C to about 55°C. The pressure P is preferably from about 6 kg/cm2 to about 15 kg/cm2, more preferably from about 9 kg/cm2 to about 11 kg/cm2. The time period of the application of the pressure P is preferably from about 1 second to about 20 seconds, more preferably from about 5 seconds to about 15 seconds. Preferably, the application of pressure P can be performed two (or more) times to increase the peel strength of the resulting laminate 70. By the application of the temperatures T1 and T2 at the pressure P, the elastomeric layer 124 is bonded to the first nonwoven layer 122 through a heat/pressure bond which is formed by softening the material of the elastomeric layer 124 (e.g., the polystyrene thermoplastic elastomer).

The elastic laminate 70 of the present invention can be incorporated into a variety of products wherein it is desired to provide an elastic stretchability in at least one structural direction either partially or entirely. Examples of such products include disposable products, including sweat bands, bandages, body wraps, and disposable garments including disposable diapers and incontinence products.

Test Methods 1. Test Method for Fiber Orientation The following method is preferably used to determine the Fiber Orientation

Ratio (FOR) of nonwoven material.

A sample nonwoven fabric (or layer) is placed on a specimen stub. The sample nonwoven fabric is fixed on the specimen stub at a flat condition so that the primary fiber direction (to be defined hereinafter) of the sample nonwoven fabric can be roughly aligned with the longitudinal direction of the photograph to be taken. A scanning electron microscope (SEM) is used to take a photograph at 50X magnification. A preferred SEM is available from Japan Electron Optics Laboratory (JEOL) Ltd., Tokyo, Japan, under Code No. JSM-5310

The following analysis is conducted on the photograph by using a digitizer. A preferred digitizer is available from Graphtec Co., Ltd., Tokyo, Japan, under Code No. KD9600. A photograph is placed on the digitizer. A square area (500 μm x 500 μm) is chosen at will in the photograph on the digitizer. The both ends of every component fiber which can be seen in the square area are manually identified by an operator and the coordinates thereof are detected and recorded by the digitizer. This work is conducted on three different square areas (each having 500 μm x 500 μm) which are chosen at will in the photograph to obtain coordinate data on the all fibers in the three different square areas. The orientation angle of each fiber is calculated based on the coordinate data. The primary fiber direction of the sample nonwoven fabric is determined by the average orientation angle, which is an average value of the all orientation angle data obtained from the three different square areas.

The Fiber Orientation Ratio within about ±10 degrees (FOR10) is determined by the following calculation:

FOR10 = NF10 / TNF x 100 (2) wherein,

NF10: the number of fibers which have orientation angles within about ±10 degrees from the primary fiber direction; and TNF: the total number of fibers measured within the three different square areas. Similarly, the Fiber Orientation Ratio within about ±20 degrees (FOR20) is determined by the following calculation:

FOR20 = NF20 / TNF x 100 (3) wherein,

NF20: the number of fibers which have orientation angles within about ±20 degrees from the primary fiber direction.

2. Test Method for Tensile Strength

The following method is preferably used to measure the tensile strength of materials. A tensile tester is prepared. The tensile tester has an upper jaw and a lower jaw which is located below the upper jaw. The upper jaw is movable and is connected to an extension force measuring means. The lower jaw is fixed in the tester. A test specimen (i.e., a nonwoven fabric to be measured) which has about 2.5 cm (about 1 inch) in width and about 10.2 cm (about 4 inches) in length is prepared and clamped with the upper jaw and the lower jaw so that the effective specimen length (L) (i.e., gauge length) is about 5.1 cm (about 2 inch). An extension force is continuously applied to the test specimen through the upper jaw at a cross-head speed of about 50 cm (about 20 inches) per minute, until the test specimen is physically broken. The applied extension force is recorded by a recorder (e.g., a computer system). The tensile strength at the breaking point is determined at the maximum tensile strength value. A tensile tester suitable for use is available from Instron Corporation (100 Royall Street, Canton, MA02021, U.S.A.) as Code No. Instron 5564.

It is understood that the examples and embodiments described herein are for illustrative purpose 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. A disposable garment having a front region, a back region and a crotch region between the front region and the back region, comprising: a chassis provided in the front, back and crotch regions and having edge lines in the front and back regions, the chassis comprising a liquid pervious topsheet, a liquid impervious backsheet associated with the topsheet, and an absorbent core disposed between the topsheet and the backsheet; and at least one pair of extensible side panels extending laterally outward from the chassis in the front or back region, wherein at least one of the side panels including an elastic laminate elastically extensible at least in the lateral direction, the elastic laminate including;
(a) an elastomeric material having a first surface and a second surface opposing the first surface, the elastomeric material including a polystyrene thermoplastic elastomer; and
(b) a first nonwoven layer including component fibers which include a polyester; wherein the elastomeric material is bonded to the first nonwoven layer through a continuous heat/pressure bond which is formed by application of a bonding temperature which is lower than the melting point of the polyester.
2. A disposable garment having a longitudinal center line, longitudinal edges, end edges, a front region, a back region and a crotch region between the front region and the back region, comprising: a chassis provided in the front, back and crotch regions and having edge lines in the front and back regions, the chassis comprising a liquid pervious topsheet, a liquid impervious backsheet associated with the topsheet, and an absorbent core disposed between the topsheet and the backsheet; and a waistband disposed along at least one of the end edges of the disposable garment, wherein the waistband includes an elastic laminate including (a) an elastomeric material having a first surface and a second surface opposing the first surface, the elastomeric material including a polystyrene thermoplastic elastomer; and
(b) a first nonwoven layer including component fibers which include a polyester; wherein the elastomeric material is bonded to the first nonwoven layer through a continuous heat/pressure bond which is formed by application of a bonding temperature which is lower than the melting point of the polyester.
3. The disposable garment of Claim 1 or 2, further comprising seams which join the chassis to the side panels to form two leg openings and a waist opening.
4. The disposable garment of Claim 1 or 2, wherein the at least one pair of the side panels comprises one pair of extensible front side panels extending laterally outward from the chassis in the front region, and one pair of extensible back side panels extending laterally outward from the chassis in the back region, and the disposable garment further comprises seams each joining the front and back side panels to form the two leg openings and the waist opening.
5. The disposable garment of Claim 1 or 2, wherein the polystyrene thermoplastic elastomer includes a polystyrene segment, and wherein the bonding temperature is higher than the glass transition temperature of the polystyrene segment.
6 The disposable garment of Claim 1 or 2, wherein the polystyrene thermoplastic elastomer is a styrene-butadiene-styrene thermoplastic elastomer, a styrene-isopren-styrene thermoplastic elastomer, a styrene-ethylene/butylene- styrene thermoplastic elastomer, a styrene-ethylene/propylene-styrene thermoplastic elastomer, a styrene-ethylene/propylene thermoplastic elastomer, a hydrogenated styrene butadiene rubber or an unsaturated styrene butadiene rubber, or a mixtures thereof.
7. The disposable garment of Claim 1 or 2, wherein the polyester is a polyethylene terephthalate, a polybutylene terephthalate, a polypropylene terephthalate or one of their relatives, or a mixtures thereof.
8. The disposable garment of Claim 1 or 2, wherein the polyester has an average molecular weight of from about 5,000 to about 60,000.
9. The disposable garment of Claim 1 or 2, wherein the elastomeric material is in the form of a continuous plane layer or a strand.
10. The disposable garment of Claim 1 or 2, wherein the elastomeric material contains from about 1 wt% to about 70 wt% of polystyrene.
PCT/US1998/020914 1998-10-02 1998-10-02 Disposable garment having elastic laminate including polystyrene thermoplastic elastomer and nonwoven layer containing polyester WO2000019950A1 (en)

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PCT/US1998/020914 WO2000019950A1 (en) 1998-10-02 1998-10-02 Disposable garment having elastic laminate including polystyrene thermoplastic elastomer and nonwoven layer containing polyester
DE1999642101 DE69942101D1 (en) 1998-10-02 1999-09-28 Elastic laminate and thus produced disposable garments
CA 2345926 CA2345926A1 (en) 1998-10-02 1999-09-28 Elastic laminates and disposable garment employing the same
EP19990956496 EP1124683B1 (en) 1998-10-02 1999-09-28 Elastic laminates and disposable garment employing the same
PCT/US1999/022473 WO2000020207A9 (en) 1998-10-02 1999-09-28 Elastic laminates and disposable garment employing the same
JP2000573544A JP2003524534A (en) 1998-10-02 1999-09-28 The elastic laminate and the disposable garment using it

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