US20120246891A1 - Combination Of Refastenable And Releasable Bonds - Google Patents

Abstract

A refastenable, pant-like garment, including a chassis including a first waist region and a second waist region, together defining a waist opening and first and second leg openings. The garment also includes a first refastenable seam joining a first distal portion of the first waist region to a first distal portion of the second waist region. The first refastenable seam includes a first refastenable bond connecting the first distal portion of the first waist region and the first distal portion of the second waist region having a first refastenable bond peel strength.

Description

• This application is a divisional of application Ser. No. 11/215,865 entitled Combination of Refastenable and Releasable Bonds and filed in the U.S. Patent and Trademark Office on Aug. 30, 2005. The entirety of the prior application is hereby incorporated by reference in this application.
BACKGROUND
• Pant-like absorbent garments, such as adult incontinence wear, infant and children's diapers, swim wear and training pants, typically have adhesive or mechanical fasteners on the sides for donning and removal, or else rely on a stretchable waist opening and leg openings to slide on and off the wearer. Absorbent garments that slide on and off a wearer can be messy after use. Furthermore, in order to remove such absorbent garments, the wearer's clothing covering the absorbent garments, such as pants, must generally be completely removed. Checking the status of the wearer's absorbent garment contents can be just as cumbersome as changing the absorbent garment.
• Refastenable seams including mechanical fasteners, such as, for example, hook and loop fasteners, have been found to be particularly beneficial when used in conjunction with pant-like absorbent garments. Refastenable seams allow for the garment to be easily applied and removed, as well as periodically opened to check for exudates and closed if no exudates are found.
• Refastenable seams generally perform much better in shear than in peel. However in the manufacturing process butt seam are generally less complicated to construct than lap seams. Butt seams are stressed predominantly in peel, while lap seams are stressed predominantly in shear. As a result, there is a need or desire for refastenable seam that can be constructed as a butt seam but will convert to a lap seam.
SUMMARY
• In response to the foregoing need, the present inventor undertook intensive research and development efforts that resulted in the discovery of a combination of refastenable and releasable bond. One version of the present invention includes a prefastened article, including a chassis including a first waist region and a second waist region, together defining a waist opening and first and second leg openings. The article also includes a refastenable seam joining a first distal portion of the first waist region to a first distal portion of the second waist region. The refastenable seam includes a first refastenable bond connecting the first distal portion of the first waist region and the first distal portion of the second waist region having a first refastenable bond peel strength. The first distal portion of the first waist region is folded and bonded with a releasable bond having a first releasable bond peel strength. Further the first refastenable bond peel strength is greater than the first releasable bond peel strength.
• Another version of the present invention provides a refastenable, pant-like garment, including a chassis including a first waist region and a second waist region, together defining a waist opening and first and second leg openings. The garment also includes a first refastenable seam joining a first distal portion of the first waist region to a first distal portion of the second waist region. The first refastenable seam includes a first refastenable bond connecting the first distal portion of the first waist region and the first distal portion of the second waist region having a first refastenable bond peel strength. The first distal portion of the first waist region being folded and bonded with a releasable bond having a first releasable bond peel strength. Further the first refastenable bond peel strength is greater than the first releasable bond peel strength. The garment also includes a second refastenable seam joining a second distal portion of the first waist region to a second distal portion of the second waist region. The second refastenable seam includes a second refastenable bond connecting the second distal portion of the first waist region and the second distal portion of the second waist region having a second refastenable bond peel strength. The second distal portion of the first waist region being folded and bonded with a releasable bond having a second releasable bond peel strength. Further the second refastenable bond peel strength is greater than the second releasable bond peel strength. Still another version of the present invention includes a refastenable joint joining a first material having a first end and a second end to a second material having a third end and a fourth end. The refastenable joint including a refastenable bond connecting the first end to the third end. The first material is folded and bonded with a releasable bond. Further separating the second end from the fourth end initially stresses the refastenable bond and the releasable bond predominantly in peel, then ruptures the releasable bond predominantly in peel, then stresses the refastenable bond predominantly in shear.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a perspective view of an absorbent garment having refastenable side seams;
• FIG. 2 is a plan view of an absorbent garment in a stretched flat state showing the surface of the garment that faces away from the wearer when the garment is worn;
• FIG. 3 is a plan view of an absorbent garment in a stretched flat state showing the surface of the garment that faces the wearer when the garment is worn, and with portions cut away to show the underlying features;
• FIGS. 4 and 4A illustrate top views of a waist region of an absorbent garment illustrating a first version of refastenable seams of the present invention;
• FIGS. 5 and 5A illustrate top views of a waist region of an absorbent garment illustrating a second version of refastenable seams of the present invention;
• FIGS. 6A-6D illustrate several seams joining a first material to asecond material116.
DEFINITIONS
• Within the context of this specification, each term or phrase below will include the following meaning or meanings.
• “Attached” refers to the joining, adhering, connecting, bonding, or the like, of at least two elements. Two elements will be considered to be attached to one another when they are attached directly to one another or indirectly to one another, such as when each is directly connected to intermediate elements.
• “Bonded” refers to the joining, adhering, connecting, attaching, or the like, of at least 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.
• “Elastomeric” and “elastic” refer to that property of a material or composite by virtue of which it tends to recover its original size and shape after removal of a force causing a deformation. It is generally preferred that the elastomeric material or composite be capable of being elongated by at least 50 percent, more preferably by at least 300 percent, of its relaxed length and recover, upon release of an applied force, at least 50 percent of its elongation.
• “Film” refers to a thermoplastic film made using a film extrusion process, such as a cast film or blown film extrusion process. The term includes apertured films, slit films, and other porous films which constitute liquid transfer films, as well as films which do not transfer liquid.
• “Hydrophilic” describes fibers or the surfaces of fibers which are wetted by the aqueous liquids in contact with the fibers. The degree of wetting of the materials can, in turn, be described in terms of the contact angles and the surface tensions of the liquids and materials involved. Equipment and techniques suitable for measuring the wettability of particular fiber materials or blends of fiber materials can be provided by a Cahn SFA-222 Surface Force Analyzer System, or a substantially equivalent system. When measured with this system, fibers having contact angles less than 90 are designated “wettable” or hydrophilic, while fibers having contact angles greater than 90 are designated “nonwettable” or hydrophobic.
• “Layer” when used in the singular can have the dual meaning of a single element or a plurality of elements.
• “Liquid impermeable,” when used in describing a layer or multi-layer laminate, means that a liquid, such as urine, will not pass through the layer or laminate, under ordinary use conditions, in a direction generally perpendicular to the plane of the layer or laminate at the point of liquid contact.
• “Liquid permeable material” or “liquid water-permeable material” refers to a material present in one or more layers, such as a film, nonwoven fabric, or open-celled foam, which is porous, and which is water permeable due to the flow of water and other aqueous liquids through the pores. The pores in the film or foam, or spaces between fibers or filaments in a nonwoven web, are large enough and frequent enough to permit leakage and flow of liquid water through the material.
• “Longitudinal” and “transverse” have their customary meaning, as indicated by the longitudinal and transverse axes depicted inFIGS. 2 and 3. The longitudinal axis lies in the plane of the article and is generally parallel to a vertical plane that bisects a standing wearer into left and right body halves when the article is worn. The transverse axis lies in the plane of the article generally perpendicular to the longitudinal axis. The article as illustrated is generally longer in the longitudinal direction than in the transverse direction, although products longer in the transverse direction are also possible.
• “Longitudinal midline” refers to a line, either real or imaginary, that runs along the longitudinal length of the chassis of an absorbent garment and bisects the chassis into two halves of equal transverse width.
• “Meltblown fiber” means fibers formed by extruding a molten thermoplastic material through a plurality of fine, usually circular, die capillaries as molten threads or filaments into converging high velocity heated gas (e.g., air) streams which attenuate the filaments of molten thermoplastic material to reduce their diameter, which may be to microfiber diameter. Thereafter, the meltblown fibers are carried by the high velocity gas stream and are deposited on a collecting surface to form a web of randomly dispersed meltblown fibers. Such a process is disclosed for example, in U.S. Pat. No. 3,849,241 to Butin et al. Meltblown fibers are microfibers which may be continuous or discontinuous, are generally smaller than about 0.6 denier, and are generally self bonding when deposited onto a collecting surface. Meltblown fibers used in the present invention are preferably substantially continuous in length.
• “Member” when used in the singular can have the dual meaning of a single element or a plurality of elements.
• “Nonwoven” and “nonwoven web” refer to materials and webs of material which are formed without the aid of a textile weaving or knitting process.
• “Offset tucked” refers to a folded position of a garment wherein the front and back regions of the garment are skewed such that the longitudinal midline of the front region of the chassis is offset or not aligned with the longitudinal midline of the back region of the chassis, and seams connecting the front and back regions are tucked.
• “Operatively joined,” in reference to the attachment of an elastic member to another element, means that the elastic member when attached to or connected to the element, or treated with heat or chemicals, by stretching, or the like, gives the element elastic properties; and with reference to the attachment of a non-elastic member to another element, means that the member and element can be attached in any suitable manner that permits or allows them to perform the intended or described function of the joinder. The joining, attaching, connecting or the like can be either directly, such as joining either member directly to an element, or can be indirectly by means of another member disposed between the first member and the first element.
• “Permanently attached” or “permanently bonded” refers to the joining, adhering, connecting, attaching, bonding, or the like, of two elements of an absorbent garment such that the elements tend to be and remain attached during normal use conditions of the absorbent garment.
• “Polymers” include, but are not limited to, homopolymers, copolymers, such as for example, block, graft, random and alternating copolymers, terpolymers, etc. and blends and modifications thereof. Furthermore, unless otherwise specifically limited, the term “polymer” shall include all possible geometrical configurations of the material. These configurations include, but are not limited to isotactic, syndiotactic and atactic symmetries.
• “Refastenable” refers to the property of two elements being capable of releasable attachment, separation, and subsequent releasable reattachment without substantial permanent deformation or rupture. The refastenable elements can be attached, separated and reattached for at least one cycle, suitably for at least 5 cycles, or suitably for at least 10 cycles.
• “A Releasable bond” and variations thereof refer to two elements being connected or connectable such that the elements tend to remain connected absent a separation force applied to one or both of the elements. The required separation force is typically less than that encountered while wearing the absorbent garment.
• “Self-engaging fastener” refers to a fastening component that can engage with another fastening component having the same structure.
• “Spunbonded fiber” refers to small diameter fibers which are formed by extruding molten thermoplastic material as filaments from a plurality of fine capillaries of a spinnerette having a circular or other configuration, with the diameter of the extruded filaments then being rapidly reduced as by, for example, in U.S. Pat. No. 4,340,563 to Appel et al., and U.S. Pat. No. 3,692,618 to Dorschner et al., U.S. Pat. No. 3,802,817 to Matsuki et al., U.S. Pat. Nos. 3,338,992 and 3,341,394 to Kinney, U.S. Pat. No. 3,502,763 to Hartmann, U.S. Pat. No. 3,502,538 to Petersen, and U.S. Pat. No. 3,542,615 to Dobo et al., each of which is incorporated herein in its entirety by reference. Spunbond fibers are quenched and generally not tacky when they are deposited onto a collecting surface. Spunbond fibers are generally continuous and often have average deniers larger than about 0.3, more particularly, between about 0.6 and 10.
• “Stretchable” means that a material can be stretched, without breaking, to at least 150% of its initial (unstretched) length in at least one direction, suitably to at least 250% of its initial length, desirably to at least 300% of its initial length.
• “Superabsorbent” or “superabsorbent material” refers to a water-swellable, water-insoluble organic or inorganic material capable, under the most favorable conditions, of absorbing at least about 15 times its weight and, more desirably, at least about 30 times its weight in an aqueous solution containing 0.9 weight percent sodium chloride. The superabsorbent materials can be natural, synthetic and modified natural polymers and materials. In addition, the superabsorbent materials can be inorganic materials, such as silica gels, or organic compounds such as cross-linked polymers.
• “Surface” includes any layer, film, woven, nonwoven, laminate, composite, or the like, whether pervious or impervious to air, gas, and/or liquids.
• “Thermoplastic” describes a material that softens when exposed to heat and which substantially returns to a nonsoftened condition when cooled to room temperature.
• These terms may be defined with additional language in the remaining portions of the specification.
DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS
• The present invention is directed to refastenable seams on garments. The principles of the present invention can be incorporated into any suitable disposable absorbent article having a pre-fastened and refastenable seam. Examples of such suitable articles include diapers, training pants, incontinence products, other personal care or health care garments, including medical garments, or the like. As used herein, the term “incontinence products” includes absorbent underwear for children, absorbent garments for children or young adults with special needs such as autistic children or others with bladder/bowel control problems as a result of physical disabilities, as well as absorbent garments for incontinent older adults. For ease of explanation, the description hereafter will be in terms of a child's training pant.
• Referring toFIG. 1, thetraining pant20 includes anabsorbent chassis32 defining afront region22, aback region24, acrotch region26 interconnecting the front and back regions, aninner surface28 which is configured to contact the wearer, and anouter surface30 opposite the inner surface which is configured to contact the wearer's clothing. With additional reference toFIGS. 2 and 3, theabsorbent chassis32 also defines a pair of transversely opposeddistal edges36 and a pair of longitudinally opposed waist edges, which are designatedfront waist edge38 and backwaist edge39. Thefront region22 is contiguous with thefront waist edge38, and theback region24 is contiguous with theback waist edge39. Thechassis32 also includes a pair of transversely opposedfront side panels34 and a pair of transversely opposed backside panels134. The front and backside panels34,134 are formed along thedistal edges36 of the chassis and can either be integrally formed with the chassis, as shown inFIG. 2, or can each include at least one separate element permanently attached to the chassis, as shown inFIGS. 1 and 3. For reference,arrows48 and49 depicting the orientation of the longitudinal axis and the transverse axis, respectively, of thetraining pant20 are illustrated inFIGS. 2 and 3.
• The illustratedabsorbent chassis32 can include anouter cover40, abodyside liner42 which is connected to the outer cover in a superposed relation, anabsorbent assembly44 which is located between theouter cover40 and thebodyside liner42, and a pair of containment flaps46, as shown inFIG. 3.
• With thetraining pant20 in the fastened position, as partially illustrated inFIG. 1, the front andback regions22 and24 are joined together to define a three-dimensional pant configuration having awaist opening50 and a pair ofleg openings52. Thefront region22 includes the portion of thetraining pant20 which, when worn, is positioned on the front of the wearer while theback region24 includes the portion of the training pant which, when worn, is positioned on the back of the wearer. Thecrotch region26 of thetraining pant20 includes the portion of the training pant which, when worn, is positioned between the legs of the wearer and covers the lower torso of the wearer. The front and backside panels34,134 include the portions of thetraining pant20 which, when worn, are positioned on the hips of the wearer.
• As shown inFIG. 3, thefront region22 of theabsorbent chassis32 includes the transversely opposedfront side panels34 and afront panel35 positioned between and interconnecting the side panels, along with a front waistelastic member54 and any other connected components. Afront waist region90 is a region of thefront panel35 along thefront waist edge38. Theback region24 of theabsorbent chassis32 includes the transversely opposed backside panels134 and aback panel135 positioned between and interconnecting the side panels, as well as a rear waistelastic member56 and any other connected components. Aback waist region92 is a region of theback panel135 along theback waist edge39. The waist edges38 and39 of theabsorbent chassis32 are configured to encircle the waist of the wearer when worn and provide thewaist opening50 which defines a waist perimeter dimension. Portions of the transversely opposeddistal edges36 of thechassis32 in thecrotch region26, along with leg end edges70 of theside panels34 and134, generally define theleg openings52.
• Theabsorbent chassis32 is configured to contain and/or absorb any body exudates discharged from the wearer. For example, theabsorbent chassis32 desirably, although not necessarily, includes the pair of containment flaps46 which are configured to provide a barrier to the transverse flow of body exudates. A flap elastic member53 (FIG. 3) can be operatively joined with eachcontainment flap46 in any suitable manner as is well known in the art. The elasticized containment flaps46 define an unattached edge which assumes an upright, generally perpendicular configuration in at least thecrotch region26 of thetraining pant20 to form a seal against the wearer's body. The containment flaps46 can be located along the transversely opposeddistal edges36 of theabsorbent chassis32, and can extend longitudinally along the entire length of the absorbent chassis or may only extend partially along the length of the absorbent chassis. Suitable constructions and arrangements for the containment flaps46 are generally well known to those skilled in the art and are described in U.S. Pat. No. 4,704,116 issued Nov. 3, 1987 to Enloe, which is incorporated herein by reference.
• To further enhance containment and/or absorption of body exudates, thetraining pant20 can include the front waistelastic member54, the rear waistelastic member56, and legelastic members58, as are known to those skilled in the art (FIG. 3). The waistelastic members54 and56 can be operatively joined to theouter cover40 and/orbodyside liner42 along the opposite waist edges38 and39 as well as over waist edges72 of theside panels34,134, and can extend over part or all of the waist edges. The legelastic members58 can be operatively joined to theouter cover40 and/orbodyside liner42 while longitudinally aligned along thedistal edges36 and positioned in thecrotch region26 of thechassis32.
• The flapelastic members53, the waistelastic members54 and56, and the legelastic members58 can be formed of any suitable elastic material. As is well known to those skilled in the art, suitable elastic materials include sheets, strands or ribbons of natural rubber, synthetic rubber, or thermoplastic elastomeric polymers. The elastic materials can be stretched and adhered to a substrate, adhered to a gathered substrate, or adhered to a substrate and then elasticized or shrunk, for example with the application of heat; such that elastic constrictive forces are imparted to the substrate. In one particular embodiment, for example, the legelastic members58 include a plurality of dry-spun coalesced multifilament spandex elastomeric threads sold under the trade name LYCRA® and available from E.I. DuPont de Nemours and Company, Wilmington, Del., U.S.A.
• Theouter cover40 desirably includes a material that is substantially liquid impermeable, and can be elastic, stretchable or nonstretchable. Theouter cover40 can be a single layer of liquid impermeable material, but desirably includes a multi-layered laminate structure in which at least one of the layers is liquid impermeable. For instance, theouter cover40 can include a liquid permeable outer layer and a liquid impermeable inner layer that are suitably joined together thermally, ultrasonically, by a laminate adhesive, or by any other suitable methods known in the art. Suitable laminate adhesives, which can be applied continuously or intermittently as beads, a spray, parallel swirls, or the like, can be obtained from Findley Adhesives, Inc., of Wauwatosa, Wis., U.S.A., or from National Starch and Chemical Company, Bridgewater, N.J., U.S.A. The liquid permeable outer layer can be any suitable material and desirably one that provides a generally cloth-like texture and/or mating fastening component qualities. One example of such a material is a 20 gsm (grams per square meter) spunbond polypropylene nonwoven web. The outer layer may also be made of those materials of which liquidpermeable bodyside liner42 is made. While it is not a necessity for the outer layer to be liquid permeable, it is desired that it provides a relatively cloth-like texture to the wearer.
• The inner layer of theouter cover40 can be both liquid and vapor impermeable, or can be liquid impermeable and vapor permeable. The inner layer is desirably manufactured from a thin plastic film, although other flexible liquid impermeable materials may also be used. The inner layer, or the liquid impermeableouter cover40 when a single layer, prevents waste material from wetting articles, such as bedsheets and clothing, as well as the wearer and care giver. A suitable liquid impermeable film for use as a liquid impermeable inner layer, or a single layer liquid impermeableouter cover40, is a 0.2 millimeter polyethylene film commercially available from Huntsman Packaging of Newport News, Va., U.S.A. If theouter cover40 is a single layer of material, it can be embossed and/or matte finished to provide a more cloth-like appearance. As earlier mentioned, the liquid impermeable material can permit vapors to escape from the interior of the disposable absorbent article, while still preventing liquids from passing through theouter cover40. A suitable “breathable” material is composed of a microporous polymer film or a nonwoven fabric that has been coated or otherwise treated to impart a desired level of liquid impermeability. A suitable microporous film is a PMP-1 film material commercially available from Mitsui Toatsu Chemicals, Inc., Tokyo, Japan, or an XKO-8044 polyolefin film commercially available from 3M Company, Minneapolis, Minn.
• The liquidpermeable bodyside liner42 is illustrated as overlying theouter cover40 andabsorbent assembly44, and may but need not have the same dimensions as theouter cover40. Thebodyside liner42 is desirably compliant, soft feeling, and non-irritating to the child's skin. Further, thebodyside liner42 can be less hydrophilic than theabsorbent assembly44, to present a relatively dry surface to the wearer and permit liquid to readily penetrate through its thickness. As mentioned, thebodyside liner42 and/or theouter cover40 can be made of a fastening component material or a mating fastening component material to eliminate the need for separately attached mating fastening components.
• Thebodyside liner42 can be manufactured from a wide selection of web materials, such as synthetic fibers (for example, polyester or polypropylene fibers), natural fibers (for example, wood or cotton fibers), a combination of natural and synthetic fibers, porous foams, reticulated foams, apertured plastic films, or the like. Various woven and nonwoven fabrics can be used for thebodyside liner42. For example, the bodyside liner can be composed of a meltblown or spunbonded web of polyolefin fibers. The bodyside liner can also be a bonded-carded web composed of natural and/or synthetic fibers. The bodyside liner can be composed of a substantially hydrophobic material, and the hydrophobic material can, optionally, be treated with a surfactant or otherwise processed to impart a desired level of wettability and hydrophilicity. For example, the material can be surface treated with about 0.45 weight percent of a surfactant mixture including AHCOVEL® N-62 from Uniqema, Inc., a division of ICI of New Castle, Del., and GLUCOPON® 220UP from Cognis Corp. of Ambler, Pa., in an active ratio of 3:1. The surfactant can be applied by any conventional means, such as spraying, printing, brush coating or the like. The surfactant can be applied to theentire bodyside liner42 or can be selectively applied to particular sections of the bodyside liner, such as the medial section along the longitudinal centerline.
• A suitable liquidpermeable bodyside liner42 is a nonwoven bicomponent web having a basis weight of about 27 gsm. The nonwoven bicomponent can be a spunbond bicomponent web, or a bonded carded bicomponent web. Suitable bicomponent staple fibers include a polyethylene/polypropylene bicomponent fiber available from CHISSO Corporation, Osaka, Japan. In this particular bicomponent fiber, the polypropylene forms the core and the polyethylene forms the sheath of the fiber. Other fiber orientations are possible, such as multi-lobe, side-by-side, end-to-end, or the like. While theouter cover40 andbodyside liner42 can include elastomeric materials, it can be desirable in some embodiments for the composite structure to be generally inelastic, where the outer cover, the bodyside liner and the absorbent assembly include materials that are generally not elastomeric.
• The absorbent assembly44 (FIG. 3) is positioned between theouter cover40 and thebodyside liner42, which components can be joined together by any suitable means, such as adhesives, as is well known in the art. Theabsorbent assembly44 can be any structure which is generally compressible, conformable, non-irritating to the child's skin, and capable of absorbing and retaining liquids and certain body wastes. Theabsorbent assembly44 can be manufactured in a wide variety of sizes and shapes, and from a wide variety of liquid absorbent materials commonly used in the art. For example, theabsorbent assembly44 can suitably include a matrix of hydrophilic fibers, such as a web of cellulosic fluff, mixed with particles of a high-absorbency material commonly known as superabsorbent material. High absorbency material can be provided in any form known in the art, including but not limited to particles, fibers, foams and films.
• In a particular embodiment, theabsorbent assembly44 includes a matrix of cellulosic fluff, such as wood pulp fluff, and superabsorbent hydrogel-forming particles. The wood pulp fluff can be exchanged with synthetic, polymeric, meltblown fibers or with a combination of meltblown fibers and natural fibers. The superabsorbent particles can be substantially homogeneously mixed with the hydrophilic fibers or can be nonuniformly mixed. The fluff and superabsorbent particles can also be selectively placed into desired zones of theabsorbent assembly44 to better contain and absorb body exudates. The concentration of the superabsorbent particles can also vary through the thickness of theabsorbent assembly44. Alternatively, theabsorbent assembly44 can include a laminate of fibrous webs and superabsorbent material or other suitable means of maintaining a superabsorbent material in a localized area.
• Suitable superabsorbent materials can be selected from natural, synthetic, and modified natural polymers and materials. The superabsorbent materials can be inorganic materials, such as silica gels, or organic compounds, such as crosslinked polymers. Suitable superabsorbent materials are available from various commercial vendors, such as Dow Chemical Company located in Midland, Mich., U.S.A., and Stockhausen GmbH & Co. KG, D-47805 Krefeld, Federal Republic of Germany. Typically, a superabsorbent material is capable of absorbing at least about 15 times its weight in water, and desirably is capable of absorbing more than about 25 times its weight in water.
• In one embodiment, theabsorbent assembly44 is generally rectangular in shape, and includes a blend of wood pulp fluff and superabsorbent material. One preferred type of fluff is identified with the trade designation CR1654, available from U.S. Alliance, Childersburg, Ala., U.S.A., and is a bleached, highly absorbent sulfate wood pulp containing primarily soft wood fibers. As a general rule, the superabsorbent material is present in theabsorbent assembly44 in an amount of from about 0 to about 90 weight percent based on total weight of the absorbent assembly. Theabsorbent assembly44 suitably has a density within the range of about 0.10 to about 0.50 grams per cubic centimeter. Theabsorbent assembly44 may or may not be wrapped or encompassed by a suitable tissue wrap that maintains the integrity and/or shape of the absorbent assembly.
• Theabsorbent chassis32 can also incorporate other materials that are designed primarily to receive, temporarily store, and/or transport liquid along the mutually facing surface with theabsorbent assembly44, thereby maximizing the absorbent capacity of the absorbent assembly. One suitable material is referred to as a surge layer (not shown) and includes a material having a basis weight of about 50 to about 120 grams per square meter, and including a through-air-bonded-carded web of a homogenous blend of 60 percent 3 denier type T-256 bicomponent fiber including a polyester core/polyethylene sheath and 40 percent 6 denier type T-295 polyester fiber, both commercially available from Kosa Corporation of Salisbury, N.C., U.S.A.
• As noted previously, the illustratedtraining pant20 has front and backside panels34,134 disposed on each side of theabsorbent chassis32. These transversely opposedfront side panels34 and transversely opposed backside panels134 can be permanently bonded to thefront panel35 andback panel135 in the respective front andback regions22,24 alongattachment lines66, and are attached to one another. Theside panels34,134 may be permanently attached using attachment means known to those skilled in the art such as adhesive, thermal or ultrasonic bonding. As mentioned, theside panels34,134 can also be formed as continuous extensions of the front andback panels35,135.
• As shown inFIG. 1, thefastening component82 can be permanently bonded to either theinner surface28 or theouter surface30 of eachfront side panel34 adjacent eachdistal edge36 of thefront region22 of thechassis32, and themating fastening components84 can be permanently bonded to either theinner surface28 or theouter surface30 of eachback side panel134 adjacent eachdistal edge36 of theback region24 of the chassis, or either theinner surface28 or theouter surface30 of thechassis32 can include fastening material86 or mating fastening material88. Thefastening components82 and themating fastening components84 may be attached to theside panels34 and thechassis32 using attachment means known to those skilled in the art such as adhesive, thermal or ultrasonic bonding.
• The fastening component may comprise adhesive, cohesive, tape, hook and loop, or any other refastenable attachment means know in the art. In one particular embodiment, thefastening components82 each include hook type fasteners and themating fastening components84 each include complementary loop type fasteners. In another particular embodiment, thefastening components82 each include loop type fasteners and themating fastening components84 each include complementary hook type fasteners. In yet another embodiment, half of thefastening components82 and half of themating fastening components84 can include hook type fasteners, while half of thefastening components82 and half of themating fastening components84 can include loop type fasteners. In still another embodiment, each of thefastening components82 and themating fastening components84 include self-engaging fasteners. Thefastening components82 and themating fastening components84 are desirably rectangular, although they may alternatively be square, round, oval, curved, discontinuous such as multiple fasteners, or any other suitable shape. Thefastening components82 andmating fastening components84 may or may not be parallel to alongitudinal midline94 of thegarment20.
• In another embodiment, the nonwoven web in theouter cover40 can be constructed of a material that is suitable for use as a loop-type fastening material, thereby eliminating the need for separate loop-type fastening components82 or84, and thefastening components82 or84 on theside panels34 or134 can be hook-type fastening components. In yet another embodiment, the nonwoven web in thebodyside liner42 can be constructed of a material that is suitable for use as a loop-type fastening material, thereby eliminating the need for separate loop-type fastening components82 or84, and thefastening components82 or84 on theside panels34 or134 can be hook-type fastening components. In still another embodiment, an inner or outer surface of either thefront side panels34 or theback side panels134 can include a loop-type fastening material, thereby eliminating the need for separate looptype fastening components82 or84.
• Loop type fasteners typically include a fabric or material having a base or backing structure and a plurality of loop members extending upwardly from at least one surface of the backing structure. The loop material can be formed of any suitable material, such as acrylic, nylon or polyester, and can be formed by methods such as warp knitting, stitch bonding or needle punching. Suitable loop materials are available from Guilford Mills, Inc., Greensboro, N.C., U.S.A. under the trade designation No. 36549.
• Hook type fasteners typically include a fabric or material having a base or backing structure and a plurality of hook members extending upwardly from at least one surface of the backing structure. In contrast to the loop type fasteners which desirably include a flexible fabric, the hook material advantageously includes a resilient material to minimize unintentional disengagement of the fastener components as a result of the hook material becoming deformed and catching on clothing or other items. Suitable hook material can be molded or extruded of nylon, polypropylene or another suitable material. Suitable single-sided hook materials for thefastening components82 or themating fastening components84 are available from commercial vendors such as Velcro Industries B.V., Amsterdam, Netherlands or affiliates thereof, and are identified as Velcro HTH-829 with a uni-directional hook pattern and having a thickness of about 0.9 millimeters (35 mils) and HTH-851 with a uni-directional hook pattern and having a thickness of about 0.5 millimeters (20 mils); and Minnesota Mining & Manufacturing Co., St. Paul, Minn. U.S.A., including specific materials identified as CS-600.
• In particular embodiments for improved fit and appearance, theside panels34,134 desirably have an average length dimension measured parallel to thelongitudinal axis48 that is about 15 percent or greater, and particularly about 25 percent or greater, of the overall length dimension of the absorbent article, also measured parallel to thelongitudinal axis48. For example, in training pants having an overall length dimension of about 54 centimeters, theside panels34,134 desirably have an average length dimension of about 10 centimeters or greater, such as about 15 centimeters. Awaist end edge72 of eachside panel34,134 can suitably be relatively straight across in the transverse direction while theleg end edge70 of eachside panel34,134 can suitably have a curvature, as shown inFIGS. 2 and 3, to allow theleg opening52 to conform about a wearer's leg.
• Each of theside panels34,134 can include one or more individual, distinct pieces of material in addition to thefastening components82,84, as shown inFIG. 3. In particular embodiments, for example, eachside panel34,134 can include first and second side panel portions that are joined at a seam, with at least one of the portions including an elastomeric material. Theside panels34,134 desirably include an elastic material capable of stretching in a direction generally parallel to thetransverse axis49 of thetraining pant20. Thefront side panels34 and theback side panels134 can be of equal widths or of different widths in the transverse direction.
• Suitable elastic materials, as well as one described process of incorporating elastic side panels into a training pant, are described in the following U.S. Pat. No. 4,940,464 issued Jul. 10, 1990 to Van Gompel et al.; U.S. Pat. No. 5,224,405 issued Jul. 6, 1993 to Pohjola; U.S. Pat. No. 5,104,116 issued Apr. 14, 1992 to Pohjola; and U.S. Pat. No. 5,046,272 issued Sep. 10, 1991 to Vogt et al.; all of which are incorporated herein by reference. In particular embodiments, the elastic material includes a stretch-thermal laminate (STL), a neck-bonded laminated (NBL), a reversibly necked laminate, or a stretch-bonded laminate (SBL) material. Methods of making such materials are well known to those skilled in the art and described in U.S. Pat. No. 4,663,220 issued May 5, 1987 to Wisneski et al.; U.S. Pat. No. 5,226,992 issued Jul. 13, 1993 to Morman; and U.S. Pat. No. 4,720,415 issued Feb. 2, 1992 to Taylor et al.; all of which are incorporated herein by reference. Alternatively, the side panel material may include other woven or nonwoven materials, such as those described above as being suitable for theouter cover40 orbodyside liner42, or stretchable but inelastic materials.
• FIG. 4 illustrates a view of atraining pant20 including arefastenable bond83 and areleasable bond96 of the present invention. Thetraining pant20 includes afastening component82 disposed in a first waist region, specifically as shown attached to thefront side panel34. Thetraining pant20 also includes amating fastening component84 disposed in the second waist region, specifically as shown attached to theback side panel134. Thefastening components82,84 define arefastenable bond83. Thetraining pant20 also includes areleasable bond96, which bonds a portion of thefront side panel34 to a second portion of thefront side panel34 maintaining afold102 in thefront side panel34. Thefold102 andreleasable bond96 are positioned such that thefastening component82, while disposed on the outer surface of thefront panel34, faces theinner surface28 of theback side panel134.
• This arrangement ofbonds83,96 and fold102 may provide many benefits, first of which may be ease of manufacture. During manufacture, thetraining pant20 may be constructed from a flat elongated web. The releasablefront side panel34 may be folded and releasably bonded96. Thefastening components82,84 may then be placed on theside panels34,134 (both applied from theinner surface28 side of the elongated web). The elongate web may then be cut into discrete articles. To form theclosed training pant20, the discrete article is folded along thetransverse axis49 bringing thefront side panel34 andrear side panel134 into face to face contact, forming arefastenable bond83 with thefastening components82,84.
• FIG. 4A illustrates a view of atraining pant20 including arefastenable bond83 and areleasable bond96 of the present invention after thefront waist region90 has been separated from theback waist region92. As illustrated inFIG. 4, separating thefront waist region90 from theback waist region92 initially stresses therefastenable bond83 and thereleasable bond96 predominantly in peel. Further separation of thewaist regions92,94 ruptures thereleasable bond96 predominantly in peel (releasable bond after rupture100). Continued separation of thewaist region92,94, stresses therefastenable bond83 predominantly in shear. The arrangement of thereleasable bond96,refastenable bond83 and fold102, may provide great benefits in the manufacture, strength and aesthetics ofrefastenable bond83.
• One way to construct the combination ofside panels34,134 is by utilizingbonds82,84,96 with the appropriate relative peel strengths. The peel strength of therefastenable bond83 may be chosen to be greater than the peel strength of thereleasable bond96. The ratio of the refastenable bond peel strength to the releasable bond peel strength may be greater than 1.5, alternatively greater than 5, alternatively greater than 10, alternatively greater than 25, alternatively greater than 50.
• Thereleasable bond96 may include ultrasonic bonding, pressure bonding, thermal bonding, adhesive bonding, cohesive bonding, magnetic bonding or any combination thereof. Thereleasable bond96 may also include hook and loop. Thereleasable bond96 may be chosen such the releasable bond afterrupture100 is skin friendly as contact with a wearer's skin is possible.
• Peel Strength Test
• This procedure is a tensile bench test to measure the peel force required to separate a mechanical fastening system that joins two materials. The peel force of separation is measured by determining load values as the two materials are pulled apart perpendicular to their plane of contact. The direction of removal (peel), in this application, is that direction in which the fastener material would generally be removed from a substrate when the product is in use. Peel strength is normalized by dividing by the contact area resulting in a force per area.
• Equipment
• 1. Tensile tester capable of obtaining a peak load and equipped with an appropriate load cell. A suitable tensile testing system is a Sintech Tensile Tester, commercially available from MTS Sintech, Research Triangle Park, N.C., under the trade designation Instron Model 4201 Tensile Tester with Sintech QAD (Quality Assurance Department) Software.
• 2. Software commercially obtained from MTS Sintech under the trade designation Sintech Testworks®.
• 3. Pneumatic-action grips commercially available from Instron Corporation, Canton, Mass., under the trade designation “Instron Model 2712-004.”
• 4. 1 by 4 inch grip faces, serrated, commercially available from Instron Corporation, Canton, Mass.
• 5. Test facility having a temperature of 23±1° C., and a relative humidity of 50±2 percent.
• Test Procedure
• 1. A sample to be tested is conditioned in the test facility for at least 4 hours prior to testing.
• 2. The load cell is calibrated and the software loaded.
• 3. The grips are installed on the tensile tester with the jaws closed.
• 4. The test condition for the tensile tester is set as follows:
• Crosshead speed=500 millimeters/minute
• Full-scale load=5 kilograms;
• Threshold=5 percent;
• Fail criterion=95 percent; and
• Gage length=50 millimeters.
• 5. The weight of the clamp is tared out.
• 6. The ear portion on the back waist region of the article is inserted into the upper jaw such that the edge of the grip face is flush with the inner edge of the fastener material.
• 7. The front waist region of the article is inserted into the lower jaw such that the inner surface of the back waist region and the outer surface of the front waist region form a 180° angle. The lower jaw is closed.
• 8. The crosshead is started in motion.
• 9. The peak load of failure is recorded. It is intended that the mode of failure is that the back waist region of the diaper separates from the front waist region of the diaper.
• FIG. 5 illustrates a view of atraining pant20 including arefastenable bond83,permanent bond98 and areleasable bond96 of the present invention. Thetraining pant20 includes afastening component82 attached to the chassis and disposed in a first waist region, specifically as shown attached to thefront side panel34. Thetraining pant20 also includes amating fastening component84 attached to the chassis and disposed in the second waist region, specifically as shown attached to theback side panel134. Thefastening components82,84 define arefastenable bond83. Thetraining pant20 also includes areleasable bond96, which bonds a portion of thefront side panel34 to a second portion of thefront side panel34 maintaining afold102 in thefront side panel34. Thefold100 andreleasable bond96 are positioned such that thefastening component82, while disposed on the outer surface of thefront panel34, faces theinner surface28 of theback side panel134. Thetraining pant20 also includes apermanent bond98, which bonds a portion of theback side panel134 to a second portion of theback side panel134 maintaining afold104 in theback side panel134. Thefold104 andpermanent bond98 are positioned such that thefastening component84, while disposed on theouter surface30 of theback panel134, faces theinner surface28 of thefront side panel34.
• The inclusion of thepermanent bond98 and fold104 may provide additional benefits with regard to manufacture. Thepermanent bond98 and fold104 may be positioned such that width of theback side band134 is reduced by the same amount as the width of thefront side panel34 is reduced by thereleasable bond96 and fold102. If original width of theside panels34,134 is the same, this equal reduction may simplify the manufacturing process by aligning thefastening components82,84 when thetraining pant20 is folded along thetransverse axis49 without further manipulation of theside panels34,134.
• FIG. 5A illustrates a view of atraining pant20 including arefastenable bond83, apermanent bond98 and areleasable bond96 of the present invention after thefront waist region90 has been separated from theback waist region92. As illustrated inFIG. 5, separating thefront waist region90 from theback waist region92 initially stresses therefastenable bond83, thepermanent bond96 and thereleasable bond96 predominantly in peel. Further separation of thewaist regions92,94 ruptures thereleasable bond96 predominantly in peel (releasable bond after rupture100). Continued separation of thewaist region92,94, stresses therefastenable bond83, andpermanent bond96 predominantly in shear. The arrangement of thereleasable bond96,permanent bond98,refastenable bond83, and folds102,104, may provide great benefits in the manufacture, strength and aesthetics ofreleasable seam80. Thepermanent bond98 and fold104 provides the added benefit in that theterminal end106 of theback side panel134 is not visible from the outside of thetraining pant20, thereby presenting a more finished looking appearance.
• The peel strength of thepermanent bond98 may be chosen to be greater than the peel strength of thereleasable bond96. The peel strength of thepermanent bond98 may be chosen to be greater than the peel strength of therefastenable bond83. The ratio of the permanent bond peel strength to the releasable bond peel strength may be greater than 1.5, alternatively greater than 5, alternatively greater than 10, alternatively greater than 25, alternatively greater than 50.
• Thepermanent bond98 may include ultrasonic bonding, pressure bonding, thermal bonding, adhesive bonding, cohesive bonding, magnetic bonding or any combination thereof. Thepermanent bond98 may also include hook and loop.
• FIGS. 6A-D illustrate several seams joining afirst material110 having afirst end112 and asecond end114 and asecond material116 having athird end118 andfourth end120, specifically thefirst end112 of thefirst material110 to thethird end118 of thesecond material116.FIGS. 6A and 6B illustrate butt seams.FIG. 6A illustrates a seam as previously known in the art. As used herein, the term “butt seam” refers to a seam or bond where the outer edges of the pieces of substrate project inward or outward from the finished product, as opposed to lying flat, thus placing the bond (122 inFIG. 6A,122 and124′ inFIG. 6B) in peel, as opposed to shearing strain.FIG. 6B illustrates a combination of arefastenbable bond122, and areleasable bond124 which join afirst end112 of afirst material110 to athird end118 of asecond material116. Thefirst material110 is folded and bonded with thereleasable bond124.
• Separating thesecond end114 of thefirst material110 from thefourth end120 of thesecond material116 initially stresses therefastenable bond122 and thereleasable bond124 predominantly in peel, then ruptures thereleasable bond124 predominantly in peel, then stresses therefastenable bond122 predominantly in shear.
• FIGS. 6B through 6D illustrate the conversion of a butt seam into a lap seam. Thereleasable bond124 has a lower peel strength thanrefastenable bond122; consequently, as force is applied to the combination ofbonds122,124,releasable bond124 will fail first. Upon failure ofreleasable bond124,refastenable bond124 is converted into a lap seam, thus placing therefastenable bond124 in shear as opposed to peel strain.
• It will be appreciated that details of the foregoing embodiments, given for purposes of illustration, are not to be construed as limiting the scope of this invention. Although only a few exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention, which is defined in the following claims and all equivalents thereto. Further, it is recognized that many embodiments may be conceived that do not achieve all of the advantages of some embodiments, particularly of the preferred embodiments, yet the absence of a particular advantage shall not be construed to necessarily mean that such an embodiment is outside the scope of the present invention.

Claims (10)

1. A refastenable joint joining a first material having a first end and a second end to a second material having a third end and a fourth end, including a refastenable bond connecting the first end to the third end, the first material being folded and bonded with a releasable bond wherein separating the second end from the fourth end initially stresses the refastenable bond and the releasable bond predominantly in peel, then ruptures the releasable bond predominantly in peel, then stresses the refastenable bond predominantly in shear.

2. The joint ofclaim 1, wherein the third end is folded and bonded with a permanent bond, separating the second end from the fourth end initially stresses the permanent bond, refastenable bond and the releasable bond in peel, then destroys the releasable bond in peel, then stresses the refastenable bond and permanent bond in shear.

3. The joint ofclaim 2, wherein the permanent bond comprises an ultrasonic bond.

4. The joint ofclaim 1, wherein the releasable bond has a releasable bond peel strength, the permanent bond has a permanent bond peel strength and the refastenable bond has a refastenable bond peel strength, the releasable bond peel strength is less than the refastenable bond peel strength, and the refastenable bond peel strength is less than the permanent bond peel strength.

5. The joint ofclaim 4, wherein a ratio of the refastenable bond peel strength to the releasable bond peel strength is greater than 1.5.

6. The joint ofclaim 4, wherein the ratio of the refastenable bond peel strength to the releasable bond peel strength is greater than 50.

7. The joint ofclaim 1, wherein the refastenable bond comprises hook and loop, cohesive, adhesive or tape.

8. The joint ofclaim 1, wherein the releasable bond comprises an ultrasonic bond.

9. The joint ofclaim 1, wherein the releasable bond comprises a pressure bond.

10. The joint ofclaim 1, wherein the releasable bond comprises an adhesive bond.

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