AU716106B2 - Monofilament reinforced fastening system for absorbent articles and method of manufacture - Google Patents

Description

WO 97/38658 PCT/US97/05790 MONOFILAMENT REINFORCED FASTENING SYSTEM FOR ABSORBENT ARTICLES AND METHOD OF MANUFACTURE BACKGROUND OF THE INVENTION The present invention relates to an improved fastening system for a garment. More particularly, the invention pertains to an improved elastic strap fastening system with button fasteners that incorporates a monofilament reinforcing strand for improved resistance to side rolling and twisting and end curling. The invention also pertains to absorbent articles and methods of making such fastening systems.

Garments such as absorbent articles come in a variety of forms, which is a result of there being so many different types of wearers and use conditions. Each form of garment incorporates a specifically-designed, compatible fastening system. Fastening systems for absorbent articles, by way of illustration, have included adhesive tapes, garment adhesives, and body adhesives; mechanical hook-and-loop type fasteners; button-type fasteners; stretchable side panels; and the like.

Many of these fastening systems have been improved in recent years as a result of their being the continued subject of intense development efforts. In complete contrast, though, is the elastic strap and button fastener fastening system that has received very little attention since its first use until today. This form of fastening system, which is especially common for adult incontinence undergarments, has been a mainstay of the field but until now has not been similarly improved as have other product features. As a result of the improvements in absorbency, gasketing, materials development, and the like, the WO 97/38658 PCT/US97/05790 elastic strap and button fastener fastening system has now become a significant factor in wearer dissatisfaction with fit and comfort of the garment.

Therefore, what is lacking and needed in the art is an improved garment fastening system that utilizes elastic straps and button fasteners and that enhances garment fit and wearer comfort.

SUMMARY OF THE INVENTION In response to the discussed deficiencies in the prior art, a new fastening system including elastic straps and button fasteners has been developed. The fastening system is suitable for use on garments such as absorbent articles and improves both product fit and wearer comfort.

Evaluation of fastening systems with elastic straps has indicated to Applicants that relatively wider elastic straps improve product fit by reducing sagging of the garment and increasing comfort, security, and leakage protection relative to narrower elastic straps.

Applicants also recognized, however, that increased strap width tends to directly increase the degree to which the side edges of the strap tend to roll, twist and rope when the elastic is stretched. This problem is attributable to use of a button or other point-attached fastener, because the lines of force when the elastic strap is stretched tend to be directed toward the attachment location, and the sides of the strap tend to fold over about an axis defined by the lines of force.

As can be appreciated, having the side edges of the elastic strap roll and twist can be very uncomfortable and can lead to skin irritation due to localized pressure of the strap.

Moreover, rolling of the strap edges can also be detrimental to the fit of the garment and lead to sagging and insecurity. Applicants have discovered that simply increasing the strap tension in an attempt to enhance fit and reduce sagging is not a desirable option, because the higher tensions merely increase the tendency of the strap edges to roll and twist and also decrease wearer comfort by localizing pressure in a small area.

Thus, while Applicants have recognized the benefits to be gained by wider elastic straps, Applicants have also discovered performance characteristics that, in addition to increased product cost, present obstacles to obtaining improved fit and comfort with fastening systems using elastic straps and buttons.

The fastening systems of the present invention overcome the above-referenced obstacles and enable the use of wider elastic straps with button or other point contact fasteners. The fastening systems of the present invention incorporate an elastomeric strap member comprising an integral monofilament strand that provides width-wise reinforcement and thus stability to the strap. In particular, the integral monofilament strand prevents lines of force created by elongation of the elastic strap from causing the side edges of the strap to roll and twist. Further, the monofilament strand is contained within the strap member in a manner that reduces the tendency of the end of the strap to curl under and minimizes the potential for skin irritation.

l0 In one aspect, the present invention concerns a fastening system for use with a garment. The fastening system includes an elastomeric strap member having longitudinal and transverse axes, opposite first and second longitudinal end edges, opposite side edges extending between the end edges, a first end region contiguous with the first end edge, and a second end region contiguous with the second end edge. The elastomeric strap member is formed of a fabric structure comprising a plurality of fabric strands and a monofilament strand that is transversely laid within the fabric structure, traversing within a transverse extent. A button adapted for releasable attachment to the garment is bonded i to the strap member in the first end region, and the second end of the strap member is attachable to the garment. The strap member also includes an end seal contiguous with the first end edge of the strap member. The end seal has a width dimension at least as great as the transverse extent of the monofilament strand, and the end seal is substantially continuous across its width dimension. The fabric strands are bonded to one another in the end seal and the monofilament strand is substantially immobilized in the end seal.

In another aspect, the invention concerns a fastening system having an S 25 elastomeric strap member and first and second buttons bonded to the strap member in respective first and second end regions. The elastomeric strap member is formed of a fabric structure including a plurality of fabric strands and a monofilament strand transversely laid within the fabric structure, traversing within a transverse extent. The strap member also includes an end seal contiguous with each of the first and second end edges of the strap member. Each end seal has a width dimension at least as great as the transverse extent of the monofilament strand and is substantially continuous across the width dimension. The fabric strands are bonded to one another in each end seal, and the monofilament strand is substantially immobilized in each end seal.

Various features of the invention are believed to contribute to reducing the extent to which the ends of the strap members curl under during use. For example, in particular [R:\LIBLL]08676.doc:MFF embodiments of the invention, the end seals are longitudinally spaced from the attachment locations of the buttons by gaps of not more than about 10 mm, and desirably by from 0 to about 6 mm. In other embodiments, the length dimension of the end seals is greater than 3 mm, and particularly at least about 10 mm. Further, the end seals in particular embodiments have a deflection resistance value of at least about 200 grams.

In another aspect, the present invention concerns an absorbent article including a garment having first and second waist regions and an intermediate section which interconnects the waist region. The garment, which defines a plurality of button holes in the first and second waist regions, is formed of a liquid-impermeable moisture barrier, and absorbent assembly disposed on the moisture barrier, and a liquid-permeable bodyside liner bonded to the moisture barrier and sandwiching the absorbent assembly between the bodyside liner and the moisture barrier. The absorbent article also includes a pair of elastomeric strap members. Each of the strap members has longitudinal and transverse axes, opposite first and second longitudinal end edges, opposite side edges extending between the end edges, a strap width defined between the side edges, a first end region contiguous with the first end edge, a second end region contiguous with the second end edge, and a central region intermediate and interconnecting the first and second end regions. Each elastomeric strap member is formed of a fabric structure S. including a plurality of fabric strands and a monofilament strand transversely laid within 20 the fabric structure, traversing within a transverse extent. First and second buttons that are adapted for releasable attachment to the button holes are bonded to each of the strap members in the respective first and second end regions. Each of the strap members also includes an end seal contiguous with each of the first and second end edges. Each end seal has a width dimension at least as great as the transverse extent of the monofilament 25 strand and is substantially continuous across the width dimension. The fabric strands are bonded to one another in each end seal and the monofilament strand is substantially immobilized in each end seal.

Applicants have discovered that absorbent articles incorporating the present fastening system tend to remain in position better and be more comfortable than current commercial products. The stabilization of the elastic straps provided by the monofilament strand minimizes or even eliminates the tendency of the side edges of the straps to roll or twist between the buttons. Consequently, the straps tend to be extremely comfortable. The manner in which the monofilament strand is contained within the strap members can reduce the tendency of the ends of the strap to curling. Further, the straps can be placed under greater tensions without tending to rope and twist, and the higher [R:ALIBLL]08676.doc:MF tensions further enhance fit and reduce sagging of the garment. Applicants have determined that wearer comfort is enhanced with strap members having a width dimension of at least about 25 mm, and more particularly at least about 30 mm for improved performance.

In still another aspect, the present invention concerns a method of making a strap member. The method comprises the steps of: providing a continuous web of elastomeric strap material comprising a fabric structure and a monofilament strand transversely laid within the fabric structure; treating discrete regions of the continuous web to form a plurality of bonded areas wherein the fabric structure is bonded to itself to immobilize the monofilament strand, each bond area having a length of at least 6 mm; transversely cutting the continuous web through the bonded areas to form a plurality of strap members, each strap member having opposite end edges with a portion of the bond area defining an end seal contiguous with each end edge, each end seal having a length of at least 3 mm and a deflection resistance value of greater than 200 grams; and bonding a pair of buttons on each strap member.

Preferably, the monofilament strand is transversely laid within the fabric structure in a sinusoidal manner.

Numerous features and advantages of the present invention will appear from the following description. In the description, reference is made to the accompanying drawings which illustrate preferred embodiments of the invention. Such embodiments do not represent the full scope of the invention. Reference should therefore be made to the claims herein for interpreting the full scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS Preferred forms of the present invention will now be described by way of S25 example only with reference to the accompanying drawings, wherein: •o Fig. 1 representatively shows a perspective view of an absorbent article according to the present invention, with portions broken away for purposes of illustration.

Fig. 2 representatively shows an enlarged perspective view of one of the two strap members shown in Fig. 1.

Fig. 3 representatively shows a further enlarged section view taken generally from the plane of the line 3-3 in Fig. 2.

[R:ALIBLL]08676.doc:MFF WO 97/38658 PCT/US97/05790 Fig. 4 representatively shows a front plan view of a test apparatus for determining a deflection resistance value for a specimen taken from one of the two strap members shown in Fig. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to Figs. 1 and 2, an absorbent article formed according to the invention is shown for purposes of illustration as a disposable undergarment 20 for adult incontinence which is maintained in position about a wearer by a fastening system comprising a pair of strap members 22. As used herein, the term "disposable" includes being disposed of after use and not intended to be washed and reused. The undergarment 20 is shown in Fig. 1 in a relaxed or non-stretched condition, with the strap members 22 only partially attached to the undergarment. The invention may also be embodied in other types of garments, such as other disposable absorbent articles, reusable absorbent articles, or the like.

The illustrated undergarment 20 has opposite, front and back longitudinal end edges 24 and 26, and longitudinal side edges 28 that extend between the longitudinal end edges. The undergarment 20 includes a first or front waist region 30, a second or back waist region 32, and an intermediate, crotch region 34 positioned between and interconnecting the front and back waist regions. The outer edges of the undergarment define a periphery 36 having generally straight end and side edges 24, 26 and 28, although the edges optionally may be curvilinear and contoured.

The front waist region 30 is contiguous with the front end edge 24 and extends longitudinally inward therefrom toward the transverse center line of the undergarment The back waist region 32 is contiguous with the back end edge 26 and extends longitudinally inward therefrom toward the transverse center line. The waist regions and 32 comprise those upper portions of undergarment 20 which, when worn, wholly or partially cover or encircle the waist or mid-lower torso of the wearer. The intermediate, crotch region 34 comprises that portion of undergarment 20 which, when worn, is positioned between the legs of the wearer and covers the lower torso of the wearer.

Thus, the crotch region 34 is the area where insults of urine typically occur in the undergarment or other disposable absorbent article.

WO 97/38658 PCT/US97/05790 The undergarment 20 includes a substantially liquid impermeable moisture barrier an absorbent assembly 42 disposed on the moisture barrier, and a substantially liquid permeable bodyside liner 44 bonded to the moisture barrier to sandwich the absorbent assembly therebetween. The moisture barrier 40 and bodyside liner 44 are desirably longer and wider than the absorbent assembly 42 so that the peripheries of the moisture barrier and bodyside liner may be bonded together using ultrasonic bonds, thermal bonds, adhesives, or other suitable means. The peripheries of the moisture barrier 40 and the bodyside liner 44 typically form the side and end margins of the undergarment 20. The absorbent assembly 42 may be bonded directly to the moisture barrier 40 and/or the bodyside liner 44 using ultrasonic bonds, thermal bonds, adhesives, or other suitable means. As used herein, the term "bonded" refers to the joining, adhering, connecting, attaching, or the like, of two elements. Two elements will be considered to be bonded together when they are bonded directly to one another or indirectly to one another, such as when each is directly bonded to intermediate elements. The terms "disposed," "disposed on," "disposed with," "disposed at," "disposed near" and variations thereof are intended to mean that one element can be integral with another element, or that one element can be a separate structure bonded to or placed with or placed near another element.

The moisture barrier 40 desirably comprises a material that is formed or treated to be liquid impermeable. Alternatively, the moisture barrier40 may comprise a liquid permeable material and other suitable means may be provided to impede liquid movement away from the absorbent assembly, such as a liquid impermeable layer (not shown) associated with the absorbent assembly 42. The moisture barrier 40 may also be gas permeable, such that gases encountered during use of the absorbent garment are able to pass through the material under ordinary use conditions, over either all or part of its surface area.

The moisture barrier 40 may comprise a single layer of material or a laminate of two or more separate layers of material. Suitable moisture barrier materials include films, wovens, nonwovens, laminates of films, wovens, and/or nonwovens, or the like. For example, the moisture barrier 40 may comprise a thin, substantially liquid impermeable web or sheet of plastic film such as polyethylene, polypropylene, polyvinyl chloride or similar material. The moisture barrier material may be transparent or opaque and have an embossed or matte surface. One particular material for the moisture barrier 40 is a polyethylene film that has a nominal thickness of about 0.025 millimeter and a systematic WO 97/38658 PCT/US97/05790 matte embossed pattern, and that has been corona treated on both sides. Another suitable moisture barrier material is an adhesive or thermal laminate comprising a cast or blown film formed of polypropylene, polyethylene or the like, and a spunbond web formed of polypropylene and polyethylene bicomponent fibers in a 50/50 side-by-side configuration.

The absorbent assembly 42 comprises materials adapted to absorb and retain liquid waste. The absorbent assembly 42 may comprise various absorbent materials, such as an air-formed batt of cellulosic fibers wood pulp fluff) or a coform material composed of a mixture of cellulosic fibers and synthetic polymer fibers. Polymer fibers may be incorporated, for example, in the manner described in U.S. Patent 5,227,107 issued July 13, 1993, to Dickenson et al. The absorbent assembly 42 may also include compounds to increase its absorbency, such as 0 95 weight percent of organic or inorganic high-absorbency materials, which are typically capable of absorbing at least about 15 and desirably more than 25 times their weight in water. Suitable highabsorbency materials are described in U.S. Patents 4,699,823 issued October 13, 1987, to Kellenberger et al. and 5,147,343 issued September 15, 1992, to Kellenberger, which are incorporated herein by reference. High-absorbency materials are available from various commercial vendors, such as Dow Chemical Company, Hoechst Celanese Corporation, and Allied Colloids, Inc. The absorbent assembly 42 may also include tissue layers or acquisition or distribution layers to help maintain the integrity of fibrous absorbents or transport liquids (not shown).

The bodyside liner 44 is formed of a liquid permeable material so that liquid waste, and possibly semi-solid waste as well, can pass through the liner and be absorbed by the absorbent assembly 42. Suitable bodyside liners 44 may comprise a nonwoven web or sheet of wet strength tissue paper, an apertured film, a spunbonded, meltblown or bonded-carded web composed of synthetic polymer filaments or fibers, such as poiypropylene, polyethylene, polyesters or the like, or a web of natural polymer filaments or fibers such as rayon or cotton. In addition, the bodyside liner 44 is desirably nonelastic and may be treated with a surfactant to aid in liquid transfer. In a particular embodiment of the invention, the liner 44 comprises a nonwoven, spunbond polypropylene fabric composed of about 2.8 3.2 denier fibers formed into a web having a basis weight of about 22 gms and density of about 0.06 gm/cc. The fabric is surface treated with about 0.28 weight percent of a surfactant commercially available from Rohm and Haas Co.

under the trade designation Triton X-102. As used herein, the term "fabric" is used to WO 97/38658 PCT/US97/05790 refer to all of the woven, knitted and nonwoven fibrous webs. The term "nonwoven web" means a web of material which is formed without the aid of a textile weaving or knitting process.

The undergarment 20 is illustrated as having a rectangular periphery 36, but may optionally be hourglass-shaped, I-shaped, T-shaped, or irregularly-shaped. The general shape of the absorbent assembly 42 may correspond to the shape of the undergarment or assume a different shape. For example, the undergarment 20 may include a relatively short absorbent assembly and separate liquid handling layers in the waist regions (not shown) as disclosed in U.S. Patent Application Serial No. 08/515,505 titled "Absorbent Article Having Improved Waist Region Dryness And Method Of Manufacture" and filed August 15, 1995, by L. LeMahieu et al. (Attorney Docket No. 12,248) and assigned to the assignee of the present application.

Desirably although not necessarily, the undergarment 20 also includes leg elastic members 46 to draw and hold the side margins of the undergarment 20 against the legs of the wearer and form a seal therewith. The elongated leg elastic members 46 are longitudinally orientated in each side margin (only one side shown in Fig. extending toward the front and back end edges 24 and 26. The leg elastic members 46 are positioned in the illustrated embodiment between the moisture barrier 40 and the bodyside liner 44. Using ultrasonic bonds, adhesives, thermal bonds, or other suitable means, the leg elastic members 46 are attached in a stretched condition to the moisture barrier the bodyside liner 44, or both, in either a straight or a curved shape. Alternatively, the leg elastic members 46 may be attached in a relaxed state to a gathered portion of the moisture barrier 40, the bodyside liner 44, or both.

The leg elastic members 46 may be formed of a dry-spun coalesced multifilament elastomeric thread sold under the tradename LYCRA® and available from E. I. Du Pont de Nemours and Company. Alternately, the elastic members may be formed of other typical elastics utilized in the undergarment-making art, such as a thin ribbon of natural rubber, a stretch bonded laminate material comprising a prestretched elastic meltblown inner layer sandwiched between and bonded to a pair of spunbond polypropylene nonwoven webs, or the like. Elasticity could also be imparted to the absorbent article by extruding a hot melt elastomeric adhesive between the moisture barrier 40 and the liner 44. Other suitable elastic gathering means are disclosed in U.S. Patents 4,938,754 to Mesek and 4,388,075 to Mesek et al.

WO 97/38658 PCT/US97/05790 The fastening system in the illustrated embodiment includes a pair of strap members 22 that are releasably attached to the front and back waist regions 30 and 32 to support the undergarment 20 about the body of the wearer. Attachment systems of this general type are disclosed in U.S. Patent B1 4,315,508 to Bolick, which is incorporated herein by reference. The present fastening system, which will now be described in greater detail, is designed to prevent rolling and twisting of the sides of the strap members 22 and prevent curling of the ends of the strap members during use. These improvements enable the use of relatively wide straps if desired, as well as improving comfort and fit of the garment.

Each strap member 22 in the illustrated embodiment is provided with first and second buttons 50 and 52 that are adapted to be releasably attached to button holes 53 provided in the undergarment 20. The button holes 53 are desirably formed in the moisture barrier 40 and bodyside liner 44, and may additionally comprise button hole reinforcement tapes (not shown) as is well known in the art. As used herein, the terms "releasably attached," "releasably engaged" and variations thereof refer to two elements being connected or connectable such that the elements tend to remain connected during use absent the wearer applying a unique separation force to one or both of the elements, and the elements being capable of separation without substantial permanent deformation or rupture.

The strap members 22 are each generally rectangular strips of material which define a longitudinal axis 54 and a generally perpendicular transverse axis 55 (Fig. Each strap member 22 has opposite, longitudinally spaced first and second end edges 56 and 58, and opposite side edges 60 and 62 extending between the end edges. The size of the strap members 22 will vary depending on the type of garment to which they are attached and the size of the intended wearers. The distance between the end edges 56 and 58 defines the strap length, which is suitably from about 15 to about 40 cm. The distance between the side edges 60 and 62 defines the strap width, which is desirably at least about 25 mm., and more particularly at least about 30 mm. for improved performance. In one particular embodiment, each strap member 22 has a length dimension of 28.6 cm.

and a width dimension of 38 mm.

For purposes of the present invention, the strap members 22 are considered as being divided longitudinally into a first end region 64, a second end region 66 and a WO 97/38658 PCT/US97/05790 central region 68 that is intermediate and interconnecting the first and second end regions. The first end region 64 is contiguous with the first end edge 56 and extends longitudinally inward therefrom to the central region 68. The second end region 66 is contiguous with the second end edge 58 and extends longitudinally inward therefrom to the central region 68.

Fig. 3 represents an enlarged section view taken generally from a plane of line 3-3 in Fig. 2, but taken slightly off center to illustrate attachment of the buttons 50 and 52.

The buttons 50 and 52 are bonded to the respective first and second end regions 64 and 66 of each strap member 22 at attachment locations 70 (Fig. An attachment location is defined by the location at which a thread 72 or other suitable means bonds a button or 52 to the strap member 22. The thread 72 is illustrated as passing through sewing holes 74 in the buttons 50 and 52 and passing through the strap member 22.

In the illustrated embodiment, the buttons 50 and 52 have an upper, contoured surface 76 and an opposite, generally flat lower surface 78. Buttons 50 and 52 suitable for use with the present invention may be formed of polypropylene and have a diameter of 22 mm., such as those available from Engineering Industries of Verona, Wisconsin, and identified as a green membrane button. In the illustrated embodiment, both end regions 64 and 66 of each strap member 22 may be attached to the undergarment 20 with the buttons 50 or 52. Alternatively, however, one end of each strap member 22 could be formed integral with the undergarment 20 or bonded thereto by other suitable means (not shown).

The term "button" is used herein to refer to a group of fasteners that can be attached to the strap members 22 at a point or an otherwise relatively small region in relation to the width dimension of the strap member. Examples of such fasteners include buttons, snaps, hook eyes, or the like. More particularly, such fasteners have an attachment location constituting less than about 40 percent of the width dimension of the strap member 22, and more particularly less than about 30 percent of the width dimension of the strap member.

Applicants have determined that these fasteners share a common problem, which is that when the elastic strap member 22 is elongated, lines of force are formed within the strap member that are directed at a gradual angle from the side edges 60 and 62 of the strap longitudinally outward and transversely inward toward the attachment location 70 of WO 97/38658 PCT/US97/05790 the fastener. In essence, the strap member 22 "necks down" near the attachment location When the strap member 22 is positioned against the body of the wearer, the side edges 60 and 62 of the strap member tend to fold about an axis defined by the lines of force. As noted previously, these folded sides would represent an irritant to the wearer because the strap forces would be concentrated in a smaller area, and they would also adversely impact the fit of the undergarment. The present invention concerns the recognition of this problem and the incorporation of an integral reinforcing material within the strap member 22 to provide improved elastic strap members with button fasteners.

The strap members 22 are formed of an elastomeric material that is adapted to provide a relatively high degree of elasticity in the longitudinal direction 54 and a relatively high degree of dimensional stability in the transverse direction 55. The terms "elastic," "elasticized" and "elasticity" as used herein refer to that property of a material by virtue of which it tends to recover its original size and shape after removal of a force causing a deformation. The term "elastomeric" refers to a material or composite which can be elongated by at least 25% of its relaxed length and which will recover, upon release of the applied force, at least 10% of its elongation. It is generally preferred that the elastomeric material be capable of being elongated by at least 100%, and more preferably by from 150 to 350%, of its relaxed length and recover, upon release of an applied force, at least 50% of its elongation. The term "force" refers to a physical influence exerted by one body on another which produces acceleration of bodies that are free to move and deformation of bodies that are not free to move.

In order to provide the desired dimensional stability in the transverse direction each strap member 22 comprises at least one relatively stiff monofilament strand disposed within a surrounding fabric structure 82 of the elastic material. The monofilament strand 80 is laid in the fabric structure 82 in a sinusoidal manner between adjacent courses as the fabric is made. A portion of the length of the monofilament strand is illustrated in Fig. 2, although it should be appreciated that the strand 80 extends the full length of the strap member 22 and forms an integral component of the elastomeric strap material.

The monofilament strand 80 suitably has a greater relative stiffness than strands of the remaining fabric structure 82. In particular embodiments, the monofilament strand is composed of nylon yarn, but alternatively may comprise any synthetic or natural strands that provide relatively greater stiffness than the remaining fabric structure 82. The strap WO 97/38658 PCT/US97/05790 members 22 may comprise one or a plurality of monofilament strands 80. For instance, in one embodiment, the strap members 22 comprise one nylon monofilament strand of about 80 denier and one nylon monofilament strand of about 330 denier. Suitable monofilament strands 80 are available from Shakespeare Monofilament company of Columbia, South Carolina, under the tradename SHAKESPEARE. The monofilament strands 80 provide transverse stability to the strap members 22 over the full strap length, and as a result, prevent rolling and twisting of the straps between the buttons 50 and 52 when elongated during use.

In one aspect of the present invention, the monofilament strand 80 does not extend across the entire strap width. Rather, the monofilament strand 80 changes directions at reversal points 84 that are disposed transversely inward of the side edges 60 and 62 of the strap member 22. The monofilament strand 80 thus has an effective width between opposite reversal points 84 that is less than the strap width. In Fig. 2, the effective width of the monofilament strand 80 is illustrated by arrow 86. Buffer zones 88 of the strap member 22 are thus provided between the reversal points 84 of the monofilament strand and the corresponding side edges 60 and 62 (Figs. 2 and The buffer zones 88 provide relatively more flexible portions of the strap member 22 that are generally more comfortable against the body of the wearer. Examples of fabrics containing inwardly reversing monofilament yarns are disclosed in U.S. Patents 4,244,199 issued January 13, 1981 to Rhode and 4,631,932 issued December 30, 1986 to Sommers, which patents are incorporated herein by reference. The effective width 86 is suitably from about 50 to 100 percent of the width dimension of the strap members 22, and particularly from about 70 to about 95 percent for improved performance, such that the buffer zones 88 have a width of from about 2 to about 10 mm.

The strap members 22 may comprise any suitable fabric structure 82 for containing the monofilament strand 80. The strap member 22 may comprise, for example, woven, knit, crotchet knit, or other suitable surrounding fabric structures. Suitable fabric structures 82 may comprise relatively inelastic yarns, relatively elastic yarns, relatively stiff monofilament yarns 80, and covering yarns. The relatively inelastic yarns and covering yarns are typically formed of polyester, nylon or other flexible synthetic or natural yarn materials. The relatively elastic yarns are typically formed of rubber, neoprene or spandex yarn materials.

WO 97/38658 PCT/US97/05790 In particular embodiments, the strap members 22 comprise a lock knit fabric formed of 150 denier polyester weft, warp and lock knit single yarns; 50 gauge (3311 denier) neoprene elastic stands; white nylon cover strands consisting of four 70 denier yarns; and monofilament strands 80. The nylon cover strands are disposed toward the bodyside of the strap member 22 opposite the buttons 50 and 52 to provide a plush surface. The strap material contains about 73.8 grains per yard polyester fiber in the weft; about 153.6 grains per yard collectively in the warp and lock knit; and about 67.8 grains per yard of the neoprene elastic. Strap members 22 of the foregoing type are produced by Shelby Elastics, Inc. of Shelby, North Carolina, under the trade designation KCM2. Other suitable materials for the strap member 22 may include different amounts of the foregoing materials, include alternative materials, or be formed by other fabrication methods.

Applicants have discovered that the ends of the elastomeric strap members 22 longitudinally outward of the button attachment locations 70 have a tendency to curl under during use. As a result, the end edges 56 and 58 are trapped between the body of the wearer and the remainder of the strap member 22, or project at an angle toward the body, and become a source of irritation. Incorporation of a monofilament strand 80 in the strap member 22 would exacerbate this problem, due to the cut ends of the rigid monofilament strand protruding from the ends 56 and 58 of the strap member and poking the skin, were it not for the Applicants' solution described below.

In one aspect, the invention pertains to the use of end seals 90 to substantially immobilize the monofilament strand 80. The end seals 90, which are illustrated in Figs.

1- 3 as cross-hatched regions, are present at both ends of the strap member 22 contiguous with each end edge 56 and 58. As best shown in Fig. 2, the end seals have a width dimension represented by arrow 92 that is parallel to the transverse axis of the strap member 22 and a length dimension represented by arrow 94 (also Fig. 3) that is parallel to the longitudinal axis 56 of the strap member. The width dimension 92 of each end seal 90 is suitably equal to or greater than the effective width 86 of the monofilament strand 80 (Fig. Additionally, the width dimension 92 is desirably although not necessarily less than the strap width.

To effectively contain the monofilament strand 80, the end seals 90 are substantially continuous across their entire width dimension 92 so that the strand 80 is immobilized at the end edges 56 and 58 of the strap member 22 regardless of the location at which the strap member is cut. The term "substantially continuous" as used herein in reference to WO 97/38658 PCT/US97/05790 an end seal 90 means that the end seal is free of gaps or interruptions that would allow the monofilament strand to protrude from the end edges 56 and 58, and desirably free of gaps or interruptions that are equal to or greater than the diameter of a monofilament strand, optically measured at the end edge 56 and 58.

The end seals 90 may be formed by ultrasonic bonding, adhesive injection, thermal bonding, ultrasonic cutting, laser cutting, or other suitable means. One significant feature of the end seals 90 is that the fabric structure 82 surrounding the monofilament strand is bonded to itself to substantially restrict or prevent movement of the monofilament strand. By doing so, the monofilament strand 80 is unable to protrude past the cut end edges 56 and 58 and poke the wearer during use. The monofilament strand 80 may also be bonded to the fabric structure 82 in the end seals 90 to further immobilize the strand In one embodiment, the end seals 90 are formed by ultrasonically bonding a portion of the strap member 22 to form the end seals 90. The ultrasonic bonding process causes the fabric structure 82 to melt adhere to itself. The term "melt adhere" is used herein to mean that individual fibers comprising the fabric structure 82 have been processed to their softening point and allowed to bond directly to other fibers of the fabric structure.

Alternatively, the fabric structure 82 may be bonded to itself and/or to the monofilament strand 80 by adhesive bonds, chemical bonds, mechanical bonds, thermal bonds, or the like to immobilize the monofilament strand.

Another aspect of the invention pertains to the ability of the end seals 90 to resist curling under during use. Applicants have determined that the ends of elastic straps 22 containing monofilament strands 80 tend to resist curling under when the end seals 90 are adapted to have a deflection resistance value of at least about 200 grams, and particularly when in combination with the end seals having a length dimension 94 of greater than 3 mm. The deflection resistance of the end seal 90 measures the amount of resistance to bending that is provided by the portion of the strap member 22 contiguous with an end edge 56 or 58. Within the above parameters, the ends of the strap members 22 tend to lay flat on the body of the wearer, thereby reducing a source of irritation.

The deflection resistance values of the end seals 90 are more particularly at least about 300 grams, and beneficially more than 400 grams, for improved performance. The deflection resistance of an end seal 90 may be altered by modifying the composition of the WO 97/38658 PCT/US97/05790 strap member 22, changing the number or weight of the monofilament strands 80, varying the width and length dimensions 92 and 94 of the end seal, adjusting the degree of bonding of fibers in the end seal, or the like. A suitable procedure for determining deflection resistance is set forth in greater detail hereinafter.

The end seals 90 are desirably contiguous with the end edges 56 and 58, substantially continuous across the width dimension 92, and have a length dimension 94 of greater than 3 mm. In particular embodiments, the end seals 90 have a length dimension 94 of at least about 10 mm, such as from about 10 to about 16 mm, for improved performance. The end seals 90 are also substantially continuous across the length dimension 94. Furthermore, the end seals 90 are desirably longitudinally spaced from the attachment locations 70 of the buttons 50 and 52 by a gap illustrated by arrow 96 in Fig. 2 of not more than about 10 mm., and more particularly not more than about 6 mm., such as from 0 to about 6 mm., for improved performance. Applicants have determined that the strap ends are more likely to curl under as the size of the gap 96 is increased.

The present end seals 90 differ significantly from those employed on conventional elastic straps of commercial disposable absorbent undergarments. Initially, it is noted that Applicants have not identified any disposable absorbent undergarments that incorporate a monofilament strand, and therefore the end seals employed on commercial products are thought to be different in the basic respect that they do not incorporate a monofilament strand. It is believed that conventional undergarment straps do not combine the following features: the end seal being contiguous with the end edge of the strap member; the end seal being substantially continuous over the width of the end seal; and the end seal having a length of greater than about 3 mm. Further, it is also believed that conventional undergarment straps do not combine the following features: the end seal being contiguous with the end edge of the strap member; (2) the end seal being substantially continuous over the width of the end seal; and the end seal being located not more than about 10 mm. from the button attachment location.

For purposes of comparison, the straps from five commercially available disposable absorbent undergarments were examined and the results are described below.

The first undergarment was representative of those sold by Kimberly-Clark Corporation of Neenah, Wisconsin, in about January of 1996 under the tradename DEPEND®. The straps had end seals that were contiguous with the end edges of the WO 97/38658 PCT/US97/05790 straps. Each end seal had a length of about 9.5 mm. and comprised a series of barshaped ultrasonic bond areas. The end seals were located within 4.5 mm. from the button attachment locations. The strap fibers were melt adhered to one another in the bond areas. Rather than being substantially continuous across the width of each end seal, the bond areas comprised only about 50 percent of the width of each end seal.

The second undergarment examined was commercially available from Osco Drug and manufactured by Pope Talbot of Portland, Oregon. The undergarment was purchased in January of 1995 under an Osco Drug brandname. The straps had end seals that were contiguous with the end edges. The end seals had a length of about 0.4 mm.; were continuous across the full width of the straps; and were located 15 mm. from the button attachment locations. The strap fibers did not appear to be melt adhered to one another.

The third undergarment examined was commercially available from Wal-Mart and manufactured by Inbrand Corporation of Marietta, Georgia. The undergarment was purchased in January of 1996 under the tradename ASSURANCETM. The straps had end seals that were contiguous with the end edges. The end seals had lengths ranging from about 0.4 to 0.8 mm.; were continuous across the full width of the straps; and were located 15 mm. from the button attachment locations. The strap fibers did not appear to be melt adhered to one another.

The fourth undergarment examined was commercially available from Walgreen Drug Stores and manufactured by ICD Industries of King of Prussia, Pennsylvania. The undergarment was purchased in January of 1996 under the tradename Walgreen Belted Undergarments. The straps had end seals that were contiguous with the end edges.

The end seals had lengths ranging from about 0.4 to 0.8 mm.; were continuous across the full width of the straps; and were located 15 mm. from the button attachment locations. The strap fibers did not appear to be melt adhered to one another.

The fifth undergarment examined was commercially available from Access Medical and manufactured by The Procter Gamble Company of Cincinnati, Ohio. The undergarment was purchased in January of 1996 under the tradename ATTENDS®. The straps had end seals that were contiguous with the end edges. The end seals had a length of about 0.8 mm.; were continuous across the full width of the straps; and were WO 97/38658 PCT/IUS97/05790 located 15 mm. from the button attachment locations. The strap fibers did not appear to be melt adhered to one another.

Applicants have determined that incorporation of the monofilament strands 80 within the strap members 22 prevents substantial force vectors from being directed from the side edges 60 and 62 at a gradual angle toward the attachment locations 70 of the buttons 50 and 52. By interrupting these inwardly-directed force vectors, the tendency of the side edges of the strap members 22 to twist and roll is greatly reduced or eliminated.

Applicants have also determined that end seals 90 that are contiguous with the end edges 56 and 58 and substantially continuous across a width dimension 92 that is equal to or greater than the effective width 86 of the monofilament strand 80 will immobilize or entrap the monofilament strand to prevent it from protruding from the end edges and poking the wearer. Further, Applicants have determined that the ends of strap members 22 will resist curling under when the end seals 90 that are contiguous with the end edges 56 and 58 and have a length dimension 94 of greater than 3 mm., and desirably a deflection resistance value of at least about 200 grams. Applicants have also determined that the ends of the strap members 22 will resist curling under when the end seals 90 are spaced from attachment locations 70 of the buttons 50 and 52 by a gap 96 of not more than about 10 mm.

In use, the undergarment 20 is positioned on the body of the wearer and secured in position using the fastening system. The wearer can engage one button 50 or 52 of each strap member 22 with a button hole 53 in the back waist region 32. After stretching or relaxing the strap members 22 to obtain the desired tension therein, the wearer can then engage the opposite button 50 or 52 of each strap member with one of the corresponding button holes 53 in the front waist region 30. During application of the strap members 22 and during use, the transverse stabilization of the strap members 22 provided by the monofilament strand 80 prevents force vectors within the strap member from being formed at an angle from the side edges 60 and 62 toward the attachment locations 70 of the buttons 50 and 52. The propensity of the side edges of the strap members 22 to roll and twist is thereby minimized or eliminated. The end seals 90 according to the present invention immobilize the monofilament strand 80 within the fabric structure 82 to eliminate a potential source of irritation and also reduce curling of the strap ends to eliminate another source of irritation.

WO 97/38658 PCT/US97/05790 Each of the foregoing or similar embodiments of the invention may be constructed by providing each of the individual components and bonding them together in the manner set forth above. The strap members 22 are desirably formed in a process that begins by providing a continuous web of elastomeric strap material. The material comprises a fabric structure 82 and a monofilament strand 80 transversely laid within the fabric structure in a sinusoidal manner. The web is advanced in an intermittent mode to an end seal forming station for processing. Discrete regions of the continuous web are treated at the forming station, such as by ultrasonic bonding, heat, adhesives, or the like, to form a plurality of bond areas wherein the fabric structure 82 is bonded to itself and/or to the monofilament strand 80 to immobilize the monofilament strand 80. Each of the bond areas desirably has a length of at least 6 mm. The continuous web is then transversely cut through the bond areas to form a plurality of strap members 22. As a result of the cutting, each cut portion of the bond area defines an end seal 90 contiguous with each end edge 56 and 58 of the strap member 22. Each end seal 90 desirably has a length of at least 3 millimeters and a deflection resistance value of greater than 200 grams. Buttons 50 and 52 are bonded in place to complete manufacture of each strap member 22.

In one embodiment, the method employs ultrasonic bonding equipment to form the end seals 90. One suitable ultrasonic thruster system is available from Dukane Corporation, Ultrasonics Division, of St. Charles, Illinois. The unit is identified as a 2000 watt, 220 DPC system referred to as model No. 2200C220T, with a 2.0:1 gain titanium booster mounted to a titanium horn, part No. 25952. The horn has working face dimensions of 28.5 by 41.1 mm. and an extra fine male knurl pattern over the entire working face to improve weld time and quality. The thruster system is mounted in a frame so that the horn when retracted is spaced from a mating anvil by a gap of 19.1 mm. The anvil has a working face of 31.8 by 44.5 mm.

For ultrasonic bonding, the elastomeric strap material is suitably maintained stationary for a brief period, such as less than about 790 milliseconds. Once the material is stationary, the thruster system is activated to advance the horn toward the anvil at 45700 kilograms per square meter force (65 psi) until the horn face contacts the elastomeric strap material. The horn continues advancing until 17578 kilograms per square meter force (25 psi) have been applied to the material. At this point, the ultrasound is activated for a sufficient ultrasound on time and with sufficient energy to form the desired bond area. The thruster system then retracts the horn. Formation of suitable end seals 90 of the type described herein may involve activation of the ultrasound WO 97/38658 PCT/US97/05790 for intervals of about 375 to 550 milliseconds and application of from about 300 to 400 joules weld energy to the material. For strap material having one side that is relatively more plush, the plush surface is desirably positioned toward the anvil for a softer surface against the body.

in particular embodiments, the ultrasonic thruster system is adapted to form a plurality of bond areas in the continuous web of elastomeric strap material. The bond areas have a length dimension of about 25.4 mm. and a width dimension equivalent to the strap width. The bond areas are thereafter cut in half using a mechanical knife.

Cutting the strap members 22 may be accomplished by a variety of mechanisms, such as shear cutting, ultrasonic cutting, laser cutting, water cutting, or the like. Shear cutting is believed to generally produce straighter end edges 56 and 58 than ultrasonic cutting, and straighter edges are believed to produce less skin irritation.

Having thus described the present invention and the process for making it, a number of examples were prepared to give a more detailed understanding of the invention. These examples and the test procedures for measuring them are set forth below. The particular amounts, proportions, compositions and parameters are meant to be exemplary, and are not intended to specifically limit the scope of the invention.

TEST PROCEDURES The deflection resistance test measures the peak load as a test specimen taken from a strap member 22 is deflected about an axis parallel to the longitudinal or length dimension of the strap member and centered in the width dimension. The test employs a Sintech material test system, also know as a tensile tester. An appropriate test system is the Model 1/S available from MTS Systems Corporation of Eden Prairie, MN. The material test system is provided with an appropriately sized load cell, for example, a 4.54 kgm. (10 lb.) load cell available from MTS Systems Corporation. The material test system is operated using suitable control software, for example, TEST WORKS® version 3.03 for WINDOWS® available from MTS Systems Corporation.

With reference to Fig. 8, a test specimen 120 is illustrated in proper position for testing in the material test system 122. The material test system 122 includes upper and lower pneumatic grips 124 and 126 that are vertically movable relative to one another.

WO 97/38658 PCT/US97/05790 The upper pneumatic grips 124 include an opposed pair of rubber-coated grip facings 130. The grip facings 130 are adapted to move toward one another through the action of pneumatic cylinders 132. As illustrated, a rigid metal plate 134 is held in place as a result of being pressed between the grip facings 130. The metal plate measures 105 mm. in length, 80 mm. in width, and 1 mm. in thickness. The metal plate 134 is positioned so that the width dimension of the plate is parallel to the direction of movement of the upper and lower pneumatic grips 124 and 126.

The lower pneumatic grips 126 include an opposed pair of rubber-coated grip facings 140. The grip facings 140 of the lower pneumatic grips 126 are controlled by pneumatic cylinders (not shown) that are maintained in a retracted position for this test.

The spacing between the two halves of the lower pneumatic grips 126 is illustrated by arrow 142 and is maintained at 21 mm. The distance between the grip facings 140 of the lower pneumatic grips 126 is illustrated by arrow 144 and is maintained at 11 mm.

The test specimen 120 is cut from the strap member 22 using a scissors or the like, in the following manner. The width of the test specimen 120 is 21 mm. and is measured parallel to the width dimension of the strap member 22. The 21 mm. width of the test specimen 120 is thus cut from the middle of the strap member 22, centered between the side edges 64 and 66. The length dimension of the test specimen 120 is taken from the portion of the strap member 122 contiguous with the end edges. The length of the test specimen 120 is the length of the end seal. Any buttons 50 or 52 that are bonded to the test specimen 120 are removed with a scissors or knife prior to testing.

The deflection resistance test is begun by calibrating and preparing the equipment as specified by the manufacturer. The test specimen 120 is positioned in the lower pneumatic grips 126 with the former non-bodyside disposed toward the metal plate 134.

The test specimen 120 is oriented such that the 21mm. width dimension is perpendicular to the plane of the metal plate 134. The edges of the test specimen 120 are allowed to rest on the top surfaces of the grip facings 140 of the lower pneumatic grips 126.

During the test, the lower pneumatic grips 126 are maintained stationary while the upper pneumatic grips 124 are moved vertically relative thereto. The metal plate 134 is squared as much as possible relative to the test specimen 120 and lowered until the metal plate almost touches the test specimen. At this time, the control software is initiated. In general, the upper pneumatic grips 124 are lowered at a rate of 5.08 cm. per minute to a WO 97/38658 PCT/US97/05790 distance of 2 cm. and then returned to their original position. The peak load measured by the load cell is recorded and represents the deflection resistance value for that test specimen 120. The control software program is reprinted below. For purposes of clarity, inactive Result Calculation lines have been omitted.

Master Name: COMPRES Method Name: strapcomp Software Version: 3.03 Method Description: Standard for COMPRESSION TESTS This Standard contains the most common results calculations required for compression testing application. Among the ASTM tests that can be performed using this Standard include D695, E9, C185.

Start of Test Messages: Start of Test Message 1 Start of Test Message 2 Start of Test Message 3 Start of Test Message 4 Pre-Sample Messages: Pre-Sample Message #1 Pre-Sample Message #2 Pre-Sample Message #3 Pre-Specimen Messages: Pre-Specimen Message #1 Pre-Specimen Message #2 Pre-Specimen Message #3 Graphics Window. Y-Axis: Y Axis Scaling Max MANUAL Y Axis Scaling Min MANUAL Y-Axis Label LOAD WO 97/38658 PCT/US97/05790 Y-Axis units Y-Axis Min Y-Axis Max Decimals Gm 0.000000 10000.000000 1 Graphics Window. X-Axis: X Axis Scaling Max MANUAL X Axis Scaling Min MANUAL X-Axis label EXTENSION X-Axis units mm X-Axis Min 0.000000 X-Axis Max 20.000000 Decimals 1 X Offset 0.000000 Test Flow: Method Access Level Specimens per Sample Speed Increment Show Graph Show Results Take Data During Pause Auto Sample Increment Auto Raw Data Save Auto Reject on Limits Auto Sample Print Discard on Reject Auto Comment Auto Sample Upload Auto Crosshead Return Gage Removal Pause for Gage Removal Reference Name: Reference Loaded: NONE [9] [999] [0.100000]

M

[Y]

[N]

[N]

[N]

[N]

[N]

[Y]

[N]

[N]

[N]

[N]

[N]

WO 97/38658 PCT/US97/05790 Configuration: Load Direction Extension Direction Compliance End Of Test Action Method Type

DOWN

DOWN

No

STOP

STANDARD

Move Segments: Type Status Direction Aquisition Data Points End Action Message Type Status Direction Aquisition Data Points End Action Message Type Status Direction Aquisition Data Points End Action Message RESET EXTENSION

ENABLE

NO CHANGE

INACTIVE

0

CONTINUE

TARE STRAIN 1

DISABLE

NO CHANGE

INACTIVE

0

CONTINUE

TARE STRAIN 2

DISABLE

NO CHANGE

INACTIVE

0

CONTINUE

Type Status GO TO STRAIN CONSTANT SPEED

ENABLE

WO 97/38658 PCTfUS97/079 Direction Aquisition Data Points End Action Message Type Status Direction Aquisition Data Points End Action Message

DOWN

ACTIVE

500

CONTINUE

Initial Speed to %strain point GO TO STRAIN CONSTANT SPEED

ENABLE

DOWN

ACTIVE

499

CONTINUE

Secondary Speed to %strain point Sample Inputs: Label 0 User Input 1 1 User Input 2 2 User Input 3 3 User Input 4 4 User Input 5 User Input 6 6 User Input 7 7 User Input 8 8 User Input 9 9 User Input 10 Default User Default 1 User Default 2 User Default 3 User Default 4 User Default 5 User Default 6 User Default 7 User Default 8 User Default 9 User Default 10 Attribute

OPTIONAL

OPTIONAL

OPTIONAL

OPTIONAL

OPTIONAL

OPTIONAL

OPTIONAL

OPTIONAL

OPTIONAL

OPTIONAL

Sample Naming Format: Alias Sample ID Alias Alias Alias Alias Length Length Length Length Length WO 97/38658 PCT/US97/05790 Channel MaDDing: Label

EXTENSION

TIME

LOAD

LOGICAL 3 LOGICAL 4 Report Header: Strap Stiff Compression Load (g) Units Class

DIMENSION

TIME

LOAD

DIMENSION

LOAD

Status

ACTIVE

ACTIVE

ACTIVE

INACTIVE

INACTIVE

Formula

PO

P1 P2 P3 P4 (Primary Strain) (Secondary Strain) Built In Reports: Built-In Report #0 Print Header Print Sample Info Print Individual Specimens Print Stats Print Calc Inputs Print Test Inputs Print Comments Built-In Report #1 Print Header Print Sample Info Print Individual Specimens Print Stats Print Calc Inputs Print Test Inputs Print Comments Built-in 1

Y

Y

Y

N

Y

Y

N

Built-In 2

Y

Y

Y

Y

Y

Y

Y

Display Units: Load Extension Speed Area Lb In In/Min Sq.ln WO 97/38658 PCT/US97/05790 Strain Time Stress Specimen Inputs: Label Units Default Attribute Panel Input Reference 0 1 2 3 4 6 7 Diameter In Length In Height In Area Sq.ln Misc.Input 1 (none) Misc.lnput 2 (none) Misc.lnput 3 (none) Misc.lnput 4 (none) 0.500 0.125 2.00 2.00 1.00 1.00 1.00 1.00

HIDDEN

HIDDEN

HIDDEN

HIDDEN

HIDDEN

HIDDEN

HIDDEN

HIDDEN

Rslt 10,21 Calculation Inputs: Label 0 Gage Length 1 Bonded Gage 2 Removal Point 3 Brk Drop 4 Brk Drop Elong Brk Load Value 6 Yield Angle 7 Yield SegLer 8 Slope Tol.

9 Slope Segler Min Slope Load 11 Max Slope Loai 12 Slope Min Strs, 13 Slope Max Strs 14 %Strain Pointi %Strain Point2 16 Elong Pointi 17 Elong Point2 18 Stress Point1

I

d .5 Units In In/In In In Lb deg Lb Lb

PSI

PSI

In In

PSI

Default 2.00 1.00 1.00 10.0 0.001 50.00 0.00 10.00 98.00 10.00 0.00 10000.00 0.00 1000.00 2.00 5.00 0.10 0.10 100.0 Attribute Panel Input DISPLAY N OPTIONAL N OPTIONAL N OPTIONAL N OPTIONAL N OPTIONAL N OPTIONAL N OPTIONAL N OPTIONAL N OPTIONAL N OPTIONAL N OPTIONAL N OPTIONAL N OPTIONAL N OPTIONAL N OPTIONAL N OPTIONAL N OPTIONAL N OPTIONAL N Reference Req. 2,2,3,9 Req 3 Rslt 27,29,31,33,35 Rslt 28,30,32,34,36 Rsit 23,25 Rslt 24,26 Rsit 37,39 WO 97/38658 PCT/US97/05790 Stress Point2 Yield Offset% Slack Pre-Load %Strain Point3 200.0 2 5.00 5.00 OPTIONAL N OPTIONAL N OPTIONAL N OPTIONAL N Rslt 38,40 RsIt 16,17,18,19,20,21 Rslt 46 Test Inputs: Label Units 0 Inital Speed In/Min 1 Secondary Speed In/Min 2 Strain Limit 3 Deformation Lim 4 Load Limit HI Lb Load Limit LO Lb 6 Ext Limit HI mm 7 Ext Lmit LO In 8 Strain Limit HI 9 Strain Limit LO Stress Limit HI PSI 11 Stress Limit LO PSI 12 Cycles (none) 13 Time Limit Sec 14 Brk Sensitivity RETURN Point In Default 2.00 4.00 100.0 200.0 25 -5000 20.0 -20.0 3000000.1 -300000.0 2999999.9 -3000000 20.0 10000 75 0.0 Attribute

DISPLAY

OPTIONAl

OPTIONAI

OPTIONAI

DISPLAY

OPTIONAI

DISPLAY

OPTIONA

OPTIONA

OPTIONA

OPTIONA

OPTIONA

OPTIONA

OPTIONA

OPTIONA

DISPLAY

Panel Input

N

S N L N L N

N

L N

N

L N L N L N L N L N L N L N L N

N

Reference MSeg 3 MSeg 4 MSeg 3 MSeg 4 Required Markers Category 1 BREAK POINT 2 YIELD POINT Code

F

Y

Attribute

MOVABLE

MOVABLE

MOVABLE

MOVABLE

3 4 MODULUS BEGIN MODULUS END Optional Markers Category AT MIDPOINT 6 AT PIP 7 AT PIP Code 0 1 2 Attribute Formula

HIDDEN

HIDDEN

HIDDEN

Inputs Reference WO 97/38658 PCT/US97/05790 8 9 11 12 13 14 AT PIP AT PIP

FREE

FREE

FREE

FREE

FREE

HIDDEN

HIDDEN

HIDDEN

HIDDEN

HIDDEN

HIDDEN

HIDDEN

@INDEX(LOAD,PEAK)

@INDEX(LOAD,PEAK)

@INDEX(LOAD,PEAK)

@INDEX(LOAD,PEAK)

@INDEX(LOAD,PEAK)

Required Calculations 0 1 2 3 4 6 7 8 9 Category

AREA

STRESS

PRIMARY STRAIN SECONDARY STRAIN

BREAK

YIELD POINT PRIMARY SLOPE SLACK COMPENSATION OFFSET YIELD GAGE LENGTH ADJUSTMENT Procedure

INACTIVE

1/AREA 1/COO 1/C00

INACTIVE

INACTIVE

INACTIVE

INACTIVE

INACTIVE

INACTIVE

Inputs

COO

CO3

CO

Result Calculations Label 0 Peak Load Category

FIXED

Formula

PEAKLOAD

Units Gm Attribute

DISPLAY

Upload and Sample Reports: Free Form Sample Report Free Form Upload Report Upload Destination Upload Filename Test Page Windows: Show Load Meter Show Extension Meter Show Strainl Meter Show Strain2 Meter Fixed Report (1) <None> COMM PORT

DATA.TMP

WO 97/38658 PCT/US97/05790 Show Machine Status Show Test Messages Show Specimen Inputs Show Description Show Panel Show Machine Show Multi-Display Show Handset Show Ruler Show Peaks Ruler Defaults: Ruler Maximum Up Ruler Maximum down Ruler Control Mode Ruler Units Ruler Gage Length Ruler Gage Length Units Ruler Decimals Precision Meter Defaults: Load Meter Full Scale Load Meter Units Load Meter Decimals Load Meter Mode Extension Meter Full Scale Extension Meter Units Extension Meter Decimals Extension Meter Mode Strain1 Meter Full Scale Strain1 Meter Units Straini Meter Decimals Strainl Meter Mode Strain2 Meter Full Scale Strain2 Meter Units Strain2 Meter Decimals Strain2 Meter Mode 40.000000 -40.000000

POSITION

In 1.000000 In 1 100.000000 Lb 1

DIGITAL

1.000000 In 1

DIGITAL

1.000000 In 1

ANALOG

1.000000 In 1

ANALOG

WO 97/38658 PCT/US97/05790 Peaks Defaults: Show Load Peak Y Load Units Lb Load Decimals 1 Show Extension Peak Y Extension Units In Extension Desimals 1 Show Strain Peak Y Strain Units Strain Desimals 1 Show Stress Peak Y Strain Units PSI Strain Desimals 1 Show Cycle Count Y Panel End Action Defaults: Load End Action STOP Extension End Action STOP Strain End Action STOP Stress End Action STOP

EXAMPLES

In each of the following examples, pairs of strap members for use with disposable absorbent undergarments were produced. Each strap member was formed of an elastomeric material comprising nylon, polyester and elastic materials, by Shelby Elastics of Shelby, North Carolina. A pair of buttons having a diameter of 22 mm. from Engineering Industries were sewn onto the opposite end regions of the strap members.

Example A Each strap member of Example A included two nylon monofilament strands transversely laid in the surrounding fabric structure in a sinusoidal manner over a width of 31.8 mm. One monofilament strand was 180 denier and the other was 330 denier. The WO 97/38658 PCT/US97/05790 strap material had a width of 38.1 mm. Each strap member was scissors cut to a length of 26.7 cm and had an ultrasonically formed end seal contiguous with each end edge.

The end seal had a length of 3.2 mm. and a width of 38.1 mm. The buttons were separated by 24.1 cm. The gap between the end seal and the button attachment location was about 10 mm.

The deflection resistance of 1 test specimen from these strap members was measured and found to have a value of 19.4 grams. The test specimens had a width of 21 mm. and a length of 3.2 mm.

Example B Each strap member of Example B included two nylon monofilament strands transversely laid in the surrounding fabric structure in a sinusoidal manner over a width of 31.8 mm. One monofilament strand was 80 denier and the other was 330 denier. The strap material had a width of 38.1 mm. Each strap member was ultrasonically cut to a length of 26.7 cm and had an ultrasonically formed end seal contiguous with each end edge. The end seal had a length of 3.2 mm. and a width of 31.8 mm. The buttons were separated by 24.1 cm. The gap between the end seal and the button attachment location was about 10 mm.

The deflection resistance of 1 test specimen from these strap members was measured and found to have a value of 14.7 grams. The test specimens had a width of 21 mm. and a length of 3.2 mm.

Example C Each strap member of Example C included one 80 denier nylon monofilament strand transversely laid in the surrounding fabric structure in a sinusoidal manner over a width of 31.8 mm. The strap material had a width of 38.1 mm. Each strap member was scissors cut to a length of 26.7 cm and had an ultrasonically formed end seal contiguous with each end edge. The end seal had a length of 3.2 mm. and a width of 38.1 mm. The buttons were separated by 24.1 cm. The gap between the end seal and the button attachment location was about 10 mm.

WO 97/38658 PCT/US97/05790 The deflection resistance of 1 test specimen from these strap members was measured and found to have a value of 14.7 grams. The test specimens had a width of 21 mm. and a length of 3.2 mm.

Each of the strap members from Examples A through C were tested in combination with a disposable absorbent undergarment. The undergarment comprised a liquid impermeable moisture barrier, a spunbond polypropylene bodyside liner bonded to the moisture barrier, and an absorbent assembly sandwiched between the moisture barrier and the bodyside liner. The moisture barrier comprised an adhesive laminate of a polyethylene film inner layer and a spunbond nonwoven outer layer. The bodyside liner, absorbent assembly and moisture barrier were bonded together using a construction adhesive. The undergarment also included leg elastic members secured along the two side margins of the garment. Button holes with reinforcement tapes were provided generally in the four corners of the undergarment.

A fit study was conducted using 30 continent female panelists having hip sizes in the range of 119.4 to 152.4 cm. Applicants hypothesized that relatively large individuals would stress the suspension system most and would therefore be able to best differentiate strap functionality. Each panelist tested each of the Examples A through C strap members. Each panelist was advised to wear an undergarment with one pair of Example strap members overnight and through the following day, for a minimum of 16 hours, and return the next day for photographs and evaluations.

The qualitative results obtained from the above test indicate that the Example C strap members did not perform as well as the Examples A and B strap members. In particular, the Example C strap members exhibited more twisting and rolling of the side edges; increased chafing and rubbing near the buttons; greater irritation during the day; and an enhanced feeling of scratchiness near the buttons. It appears to Applicants that functionality improves as the monofilament size and number of strands increase.

Example D Each strap member of Example D included two nylon monofilament strands transversely laid in the surrounding fabric structure in a sinusoidal manner over a width of 31.8 mm. One monofilament strand was 80 denier and the other was 330 denier. The strap material had a width of 38.1 mm. Each strap member was scissors cut to a length WO 97/38658 PCT/US97/05790 of 28.6 cm and had an ultrasonically formed end seal contiguous with each end edge.

The end seal had a length of 3.2 mm. and a width of 38.1 mm. The buttons were separated by 26 cm. The gap between the end seal and the button attachment location was about 10 mm.

The deflection resistance of 1 test specimen from these strap members was measured and found to have a value of 107.6 grams. The test specimens had a width of 21 mm. and a length of 3.2 mm.

Example E Each strap member of Example E included two nylon monofilament strands transversely laid in the surrounding fabric structure in a sinusoidal manner over a width of 31.8 mm. One monofilament strand was 180 denier and the other was 520 denier. The strap material had a width of 38.1 mm. Each strap member was scissors cut to a length of 28.6 cm and had an ultrasonically formed end seal contiguous with each end edge.

The end seal had a length of 3.2 mm. and a width of 38.1 mm. The buttons were separated by 26 cm. The gap between the end seal and the button attachment location was about 10 mm.

The deflection resistance of 1 test specimen from these strap members was measured and found to have a value of 146.4 grams. The test specimens had a width of 21 mm. and a length of 3.2 mm.

Example F Each strap member of Example F included two nylon monofilament strands transversely laid in the surrounding fabric structure in a sinusoidal manner over a width of 31.8 mm. One monofilament strand was 180 denier and the other was 520 denier. The strap material had a width of 38.1 mm. Each strap member was scissors cut to a length of 26.7 cm and had an ultrasonically formed end seal contiguous with each end edge.

The end seal had a length of 3.2 mm. and a width of 38.1 mm. The buttons were separated by 24.1 cm. The gap between the end seal and the button attachment location was about 10 mm.

WO 97/38658 PCTIUS97/05790 The deflection resistance of Example F strap members should be similar to Example E strap members.

Each of the strap members from Examples D through F were tested in combination with disposable absorbent undergarments as described in relation to the testing of Examples A through C. A fit study was conducted using 12 continent female panelists having hip sizes in the range of 106.7 to 152.4 cm. Each panelist tested each of the Examples D through F strap members. Each panelist was advised to wear an undergarment with one pair of Example strap members overnight and through the following day, for a minimum of 16 hours, and return the next day for photographs and evaluations.

The qualitative results obtained from the test of Examples D through F suggest that an increase in the size of the monofilament contributes to a reduction in twisting and rolling.

Control Example G Each strap member of Control Example G was representative of those sold by Kimberly-Clark Corporation of Neenah, Wisconsin, in about January of 1996 under the tradename DEPEND®. Each strap member had a width of 25.4 mm. and was scissors cut to a length of 26.0 cm. The straps had end seals that were contiguous with the end edges of the straps. Each end seal had a length of about 9.5 mm. and comprised a series of bar-shaped ultrasonic bond areas. The strap fibers were melt adhered to one another in the bond areas. Rather than being substantially continuous across the width of each end seal, the bond areas comprised only about 50 percent of the width of each end seal. The buttons were separated by 22.9 cm. and the gap between the end seals and the button attachment locations was about 5 mm.

The deflection resistance of 1 test specimen from these strap members was measured and found to have a value of 42.6 grams. The test specimens had a width of 21 mm. and a length of 9.5 mm.

WO 97/38658 PCT/US97/05790 Example H Each strap member of Example H included two nylon monofilament strands transversely laid in the surrounding fabric structure in a sinusoidal manner over a width of 31.8 mm. One monofilament strand was 80 denier and the other was 330 denier. The strap material had a width of 38.1 mm. Each strap member was scissors cut to a length of 28.6 cm and had an ultrasonically formed end seal contiguous with each end edge.

The end seal had a length of 19.1 mm. and a width of 38.1 mm. The buttons were separated by 25.4 cm. and bonded through the end seals so that there was no gap between the end seals and the button attachment locations.

The deflection resistance of 5 test specimens from these strap members were measured and found to have an average value of 1292 grams, with a standard deviation of 68.4 grams. The test specimens had a width of 21 mm. and a length of 19.1 mm.

ExamDle I Each strap member of Example I was similar to those of Example H except that the end seal had a length of 15.9 mm. The end seal resides essentially under the button leaving no gap between the end seal and the button attachment location. The deflection resistance of 5 test specimens from these strap members were measured and found to have an average value of 1117 grams, with a standard deviation of 116.7 grams. The test specimens had a width of 21 mm. and a length of 15.9 mm.

Example J Each strap member of Example J was similar to those of Example H except that the end seal had a length of 12.7 mm. The gap between the end seal and the button attachment location was about 3 mm. The deflection resistance of 5 test specimens from these strap members were measured and found to have an average value of 836 grams, with a standard deviation of 20.4 grams. The test specimens had a width of 21 mm. and a length of 12.7 mm.

WO 97/38658 PCT/US97/05790 Example K Each strap member of Example K was similar to those of Example H except that the end seal had a length of 9.5 mm. The gap between the end seal and the button attachment location was about 7 mm. The deflection resistance of 5 test specimens from these strap members were measured and found to have an average value of 667 grams, with a standard deviation of 47.4 grams. The test specimens had a width of 21 mm. and a length of 9.5 mm.

Each of the strap members from Control Example G and Examples H through K were tested in combination with disposable absorbent undergarments as described in relation to the testing of Examples A through C. A fit study was conducted using 12 continent female panelists having hip sizes in the range of 106.7 to 152.4 cm. Each panelist tested each of the Examples G through K strap members. Each panelist was advised to wear an undergarment with one pair of Example strap members overnight and through the following day, for a minimum of 16 hours, and return the next day for photographs and evaluations.

The qualitative results obtained from the test of Control Example G and Examples H through K suggest that the stiffened end seal itself and the gap between the end seal and the button attachment location are important factors in performance. Applicants theorize that irritation attributable to strap end curling tends to increase when the gap between the button attachment location and the end seal gets larger. In particular, as the gap increases beyond about 6 mm., the strap ends begin to curl under more which leads to noticeable redness and chafing/rubbing near the buttons. Additionally, when the button attachment location is placed through the end seal, that is a gap of zero, the straps begin to feel scratchy and there is again noticeable redness.

Example L Each strap member of Example L included two nylon monofilament strands transversely laid in the surrounding fabric structure in a sinusoidal manner over a width of 31.8 mm. One monofilament strand was 80 denier and the other was 330 denier. The strap material had a width of 38.1 mm. Each strap member was scissors cut to a length of 28.6 cm and had an ultrasonically formed end seal contiguous with each end edge.

The end seal had a length of 12.7 mm. and a width of 38.1 mm. The buttons were WO 97/38658 PCTIUS97/05790 separated by 25.4 cm. and the gap between the end seals and the button attachment locations was about 3 mm.

The deflection resistance of 10 test specimens from these strap members were measured and found to have an average value of 439 grams, with a standard deviation of 85.9 grams. The test specimens had a width of 21 mm. and a length of 12.7 mm.

Example M Each strap member of Example M was similar to those of Example L except for the deflection resistance of the strap member. The deflection resistance of 10 test specimens from the Example M strap members were measured and found to have an average value of 227 grams, with a standard deviation of 44.2 grams. The test specimens had a width of 21 mm. and a length of 12.7 mm.

Example N Each strap member of Example N was similar to those of Example L except for the deflection resistance of the strap member. The deflection resistance of 10 test specimens from the Example N strap members were measured and found to have an average value of 617 grams, with a standard deviation of 125.1 grams. The test specimens had a width of 21 mm. and a length of 12.7 mm.

Each of the strap members from Examples L through N were tested in combination with disposable absorbent undergarments as described in relation to the testing of Examples A through C. A fit study was conducted using 10 continent female panelists having hip sizes in the range of 109 to 152.4 cm. Each panelist tested each of the Example L through N strap members. Each panelist was advised to wear an undergarment with one pair of Example strap members overnight and through the following day, for a minimum of 16 hours, and return the next day for photographs and evaluations.

The qualitative results obtained from the test of Examples L through N suggest that end seal deflection resistance is an important characteristic for the strap members that were tested. The results indicate to Applicants that increased end seal stiffness reduced the amount that strap ends curled under and irritated the wearer. As end seal stiffness WO 97/38658 PCT/US97/05790 decreased below that of Example L, increased levels of red marking, indentation, and irritation were observed. Further, the end seals of Example N were found to curl under significantly less that those of Example L, as determined by noting whether the end did not curl, curled at an angle up to 45 degrees, or curled at an angle of more than degrees.

The foregoing detailed description has been for the purpose of illustration. Thus, a number of modifications and changes may be made without departing from the spirit and scope of the present invention. For instance, alternative or optional features described as part of one embodiment can be used to yield another embodiment. Additionally, two named components could represent portions of the same structure. Therefore, the invention should not be limited by the specific embodiments described, but only by the claims.

Claims (21)

1. A fastening system for use with a garment, the fastening system comprising: an elastomeric strap member having longitudinal and transverse axes, opposite first and second longitudinal end edges, opposite side edges extending between the end edges, a first end region contiguous with the first end edge, and a second end region contiguous with the second end edge, the elastomeric strap member comprising: a fabric structure comprising a plurality of fabric strands; and a monofilament strand transversely laid within the fabric structure, the monofilament strand traversing within a transverse extent; a button bonded to the strap member in the first end region and adapted for releasable attachment to the garment; and means for attaching the second end region to the garment; wherein the strap member further comprises an end seal contiguous with the first end edge, the end seal having a width dimension at least as great as the transverse extent of the monofilament strand and being substantially continuous across the width dimension, the fabric strands being bonded to one another in the end seal and the i"..monofilament strand being substantially immobilized in the end seal.

2. The fastening system of claim 1, wherein the button is bonded to the i" 20 strap member at an attachment location and the end seal is longitudinally spaced from the :•"attachmnent location by a gap of not more than about 10 mm.

3. The fastening system of claim 2, wherein the gap is from 0 to about 6 mm.

4. The fastening system of claim 1, wherein the transverse extent of the 25 monofilament strand is less than a strap width defined between the side edges of the strap member. The fastening system of claim 4, wherein the width dimension of the "end seal is less than the strap width.

6. The fastening system of claim 1, wherein the end seal has a length dimension of greater than 3 mm.

7. The fastening system of claim 6, wherein the end seal has a length dimension of at least about 10 mm.

8. The fastening system of claim 6, wherein the end seal has a deflection resistance value of at least about 200 grams. 35 9. The fastening system of claim 1, wherein the end seal has a deflection resistance value of at least about 200 grams. [R:\LIBLL]08676.doc:MFF The fastening system of claim 1, wherein the strap member comprises a plurality of monofilament strands.

11. The fastening system of claim 1, wherein the strap member has a strap width of at least about 30 mm.

12. The fastening system of claim 1, wherein the fabric strands are melt adhered to the monofilament strand.

13. A fastening system, comprising: an elastomeric strap member having longitudinal and transverse axes, opposite first and second longitudinal end edges, opposite side edges extending between the end edges, a first end region contiguous with the first end edge, and a second end region contiguous with the second end edge, the elastomeric strap member comprising: a fabric structure comprising a plurality of fabric strands; and a monofilament strand transversely laid within the fabric structure, the monofilament strand traversing within a transverse extent; first and second buttons bonded to the strap member in the respective first and second end regions; and wherein the strap member further comprises an end seal contiguous with each of the first and second end edges, each end seal having a width dimension at least as great as the transverse extent of the monofilament strand and being substantially continuous 20 across the width dimension, the fabric strands being bonded to one another in each end seal and the monofilament strand being substantially immobilized in each end seal. o 14. The fastening system of claim 13, wherein the buttons are bonded to the strap member at attachment locations and the end seals are longitudinally spaced from the attachment locations by gaps of not more than about 10 mm. o 25 15. The fastening system of claim 13, wherein the gaps are from 0 to about S: 6 mm.

16. The fastening system of claim 13, wherein the transverse extent of the monofilament strand is less than a strap width defined between the side edges of the strap member.

17. The fastening system of claim 13, wherein the end seals have a length dimension of greater than 3 mm.

18. The fastening system of claim 13, wherein the end seals have a length dimension of at least 10 mm.

19. The fastening system of claim 13, wherein the end seals have a deflection resistance value of at least about 200 grams. An absorbent article, comprising: [R:\LIBLL]08676doc:MFF a garment having first and second waist regions and an intermediate section which interconnects the waist regions, the garment defining a plurality of button holes in the first and second waist regions, the garment comprising a liquid-impermeable moisture barrier, an absorbent assembly disposed on the moisture barrier, and a liquid-permeable bodyside liner bonded to the moisture barrier and sandwiching the absorbent assembly between the bodyside liner and the moisture barrier; a pair of elastomeric strap members, each of the strap members having longitudinal and transverse axes, opposite first and second longitudinal end edges, opposite side edges extending between the end edges, a strap width defined between the 1o side edges, a first end region contiguous with the first end edge, a second end region contiguous with the second end edge, and a central region intermediate and interconnecting the first and second end regions, each elastomeric strap member comprising: a fabric structure comprising a plurality of fabric strands; and a monofilament strand transversely laid within the fabric structure, the monofilament strand traversing within a transverse extent; first and second buttons bonded to each of the strap members in the respective first and second end regions, the buttons adapted for relasable attachment to the button holes; and 20 wherein each of the strap members further comprises an end seal contiguous with each of the first and second end edges, each end seal having a width dimension at least as great as the transverse extent of the monofilament strand and being substantially continuous across the width dimension, the fabric strands being bonded to one another in each end seal and the monofilament strand being substantially immobilized in each end 25 seal.

21. The absorbent article of claim 20, wherein the buttons are bonded to the strap members at attachment locations and the end seals are longitudinally spaced from the attachment locations by gaps of from 0 to about 6 mm.

22. The absorbent article of claim 20, wherein the end seals have a length dimension of greater than 3 mm.

23. The absorbent article of claim 20, wherein the end seals have a deflection resistance value of at least about 200 grams.

24. A method of making a strap member, comprising the steps of: providing a continuous web of elastomeric strap material comprising a fabric S">3's structure and a monofilament strand transversely laid within the fabric structure; [R:\LIBLL]08676.doc:MFF 43 treating discrete regions of the continuous web to form a plurality of bonded areas wherein the fabric structure is bonded to itself to immobilize the monofilament strand, each bond area having a length of at least 6 mm; transversely cutting the continuous web through the bonded areas to form a plurality of strap members, each strap member having opposite end edges with a portion of the bond area defining an end seal contiguous with each end edge, each end seal having a length of at least 3 mm and a deflection resistance value of greater than 200 grams; and bonding a pair of buttons on each strap member. The method of claim 24, wherein the monofilament strand is laid within the fabric structure in a sinusoidal manner.

26. A fastening system substantially as hereinbefore described with reference to the accompanying drawings.

27. An absorbent article substantially as hereinbefore described with reference to the accompanying drawings.

28. A method of making a strap member, said method being substantially as hereinbefore described with reference to the accompanying drawings. Dated 29 November, 1999 Kimberly-Clark Worldwide, Inc. Patent Attorneys for the Applicant/Nominated Person 20 SPRUSON FERGUSON o* «e [R:\LIBLL]08676.doc:MFF