Abstract:
Fastening systems for releasably securing two components together include tab and landing members. In a first arrangement, a Z-fold tab member has combined mechanical and adhesive engagement. A second arrangement includes adjacent adhesive and cohesive contact portions. A third arrangement contoured apertures and mechanical engaging elements. A fourth arrangement includes apertures and mechanical engaging elements sized and arranged so that each aperture receives a plurality of mechanical engaging elements. A fifth arrangement includes tab and landing members that cooperate to provide a color indicia of secure adhesive engagement.

Description:
This application claims the priority of U.S. Provisional Application No. 60/010,029, filed Jan. 16, 1996. 
    
    
     BACKGROUND OF THE INVENTION AND RELATED ART 
     The present invention relates to closures for fastening adjacent portions of materials or components together. The closures are useful as fastening system closures for disposable diapers. 
     Diapers of this general type are widely used. A typical diaper construction comprises an absorbent pad or batt or the like enclosed in an outer plastic shell or a non-woven backsheet that is non-woven fabric laminated with a water impermeable layer such as a polyethylene film. A water permeable inner shell or liner is also provided to promote separation of fluid from the user. 
     The fastener tape system generally includes adhesive tabs fastened to one end of the diaper assembly construction at each lateral side of the diaper in a permanent “factory joint” by the diaper manufacturer using adhesives or other techniques. The tabs have a face coated with pressure-sensitive adhesive. The tabs are releasably attachable to the other end of the diaper at each lateral side in a “user joint”. The attachment is releasable both to allow permanent removal of the diaper and to allow unfastening to inspect the diaper followed by refastening if indicated. 
     The user joint may be formed by direct connection of the tab to the diaper outer surface whether the latter is formed of a plastic film or a non-woven backsheet. In the case of plastic film shells, it is typical to provide a “landing zone or member” formed of reinforcing tape or the like for receiving the end of the tab to form the user joint. The landing zone may provide a plastic surface or a non-woven surface and may comprise a knit type fabric landing pad. 
     The fastener tape system may rely solely upon pressure-sensitive adhesive in the formation of the user joint as shown in U.S. Pat. Nos. 4,795,456, 4,710,190, 4,020,842 and 3,833,456. The use of combined adhesive and mechanical fastener systems is shown in U.S. Pat. Nos. 5,019,065, 5,053,028 and 4,869,724. The teachings of all of these patents being incorporated herein by reference. 
     The use of extensible or stretchable tabs to promote user comfort through better fit and more secure mounting is also known in the art. The tabs operate as extensible diaper side waistbands. Examples of such diaper fastening systems are disclosed in U.S. Pat. Nos. 4,795,456, 4,066,081, 4,051,853 and 3,800,796. The teachings of these patents being incorporated herein by reference. 
     Related art includes U.S. Pat. Nos. 4,465,717, 4,662,875, 5,051,259, 5,106,384, 5,133,707, 5,531,731, 5,591,521 and European Publication No. 0 191 355. 
     SUMMARY OF THE INVENTION 
     The present invention has a number of different aspects relating to improvements in diaper tab fastening systems. These improvements may be used alone or in combination in a fastener system. The fastener system may include an extensible or substantially nonextensible element or tab member. 
     In a first aspect, the fastening system includes overlying or spatially combined adhesive and mechanical fastening attachments in a tab having an efficient Z-fold configuration. Upon deployment of such tab arrangement to close the diaper, the adhesive provides immediate tack strength and the mechanical attachment provides improved shear strength. The mechanical and adhesive attachments each contribute to the total integrity or strength of the diaper closure or user joint, and neither has to be fully effective to provide the required total closure strength. 
     In a second aspect, the fastening system has a combined adhesive closure system including both adhesive and cohesive elastomers to effect closure. In this manner, the aggressiveness of adhesives is attained as well as the contaminate resistance of cohesives. 
     In a third aspect, the fastening system includes a mechanical fastening system having mechanically engaging elements adapted to be received in contoured or obliquely extending apertures in the tab. The mechanical engaging elements have shaped base portions extending to head portions for interengagment within the apertures. 
     In a fourth aspect, the fastening system includes a mechanical fastening system having an open mesh tab adapted to receive a plurality of mechanical engaging elements. The apertures and mechanical engaging elements are sized and arranged to provide engagement of a plurality of elements in each of the apertures. 
     In a fifth aspect, the fastening system includes a color indication of proper adhesive engagement of the tab and landing members. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a fragmentary perspective view showing a diaper having a fastener system including a tab member in the deployed condition ready for securement to a landing member in accordance with the present invention; 
     FIG. 2 is an elevational view of the tab member of FIG. 1 in the storage position with the folded portions slightly spaced for clarity of illustration; 
     FIG. 3 is a schematic perspective view of various mechanical fastener elements that may be used in the fastener system of FIG. 1, 
     FIG. 4 is a fragmentary perspective view showing a diaper having a fastener system including a tab member in the deployed condition ready for securement to a landing member in accordance with another embodiment of the present invention; 
     FIG. 5 is a fragmentary perspective view showing a diaper having a fastener system including a tab member in the deployed condition ready for securement to a landing member in accordance with a further embodiment of the present invention; 
     FIG. 6 is a fragmentary sectional view on an enlarged scale taken along the line  6 — 6  in FIG. 5; 
     FIG. 7 is a fragmentary sectional view similar to FIG. 6 showing the tab and landing members of FIG. 5 in a securement position; 
     FIG. 8 is a fragmentary perspective view showing a diaper having a fastener system including a tab member in the deployed condition ready for securement to a landing member in accordance with yet a further embodiment of the present invention; 
     FIG. 9 is a fragmentary elevational view on an enlarged scale showing the tab and landing members of FIG. 8 in a securement position; 
     FIG. 10 is a fragmentary perspective view showing a diaper having a fastener system including a tab member in the deployed condition ready for securement to a landing member in accordance with yet a further embodiment of the present invention; and 
     FIG. 11 is a fragmentary sectional view on an enlarged scale showing the tab and landing member of FIG. 10 adhesively engaged. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Herein, pressure-sensitive adhesive layers or applications are variously referred to in the tab fastener systems. The adhesive layer or application may be provided using known adhesive materials such as pressure-sensitive adhesives including acrylic resin and natural or synthetic based rubber adhesives. Preferred adhesives include hot melt pressure-sensitive adhesives of the A-B-A block copolymer type comprising an elastomeric B-block derived from isoprene and thermoplastic A-blocks derived from styrene as disclosed in U.S. Pat. No. 3,932,328. Illustrative rubber based adhesives include styrene-isoprene-styrene and styrene-butadiene-styrene which may optionally contain diblock components such as styrene isoprene and styrene butadiene. The adhesives may be applied using hot-melt, solvent or emulsion techniques. 
     The provision of extensible facestock layers and/or tab constructions referred to herein may be formed or provided in any of the following manners. 
     The facestock film may be made extensible or stretchable by forming it of extrudable elastomers such as the thermoplastic elastomers sold by the Shell Chemical Company under the designation Kraton. These elastomers may be SBS, SIS, SI, S(IS) X  and SEBS block copolymers and mixtures thereof. The facestock may also be formed of a polyurethane, polyethylene and polypropylene copolymer or EVA polymer of suitable elastic characteristics. The resulting facestock or tab should have an extensibility or elasticity similar to that of the films disclosed in U.S. Pat. No. 5,057,097 to Gesp, and owned by the assignee herein. 
     The extensibility may also be provided by coextrusion processing with combinations of extensible and nonextensible polymers. More particularly, a side-by-side coextrusion including adjacent portions of extensible polymer film and nonextensible polymer film may be made. The diaper tab may be cut from the coextruded film and include one or more extensible film portions extending across the width of the tab. The coextrusion processing requires a matching or near matching of the melt flow characteristics of the polymers forming the facestock. Such matching and processing techniques are known in the art and illustrated, for example, in U.S. Pat. No. 3,800,796. 
     The facestock may comprise an extensible fabric such as a stretchable non-woven or woven fabric. Preferably, the fabric has a higher tensile modulus and is less extensible in the fabric manufacture machine direction than in the cross direction. This will facilitate handling of the fabric web in adhesive coating and cutting processing. The tabs may be cut across the width or in the cross machine direction of fabric manufacture. Suitable non-woven fabrics are commercially available. For example, Kimberly-Clark Corporation of Neenah, Wisconsin markets a suitable fabric under the name Demique. A suitable polyurethane non-woven fabric is sold by Kanebo Company of Japan. Suitable woven fabrics are commercially by Bloomburg Mills of Bloomburg, Pa. and the Comco Company of Charlotte, N.C. 
     The tab may be nonextensible and formed of conventional polymers such as polypropylene, polyethylene and blends of copolymers thereof. Such tabs typically include an extruded facestock layer or film formed of such polymers. 
     Referring to FIGS. 1 and 2, a fastener system  20  for releasably closing a diaper  22  having opposed longitudinal diaper ends  24  and  26  is shown. The fastener system includes a landing member  28  mounted to the longitudinal diaper end  24  and a diaper tab  30  mounted to the longitudinal diaper end  26 . The tab  30  includes an extensible facestock layer  32  having intermediate fold lines or planes  34  and  36 . The fold lines  34  and  36  divide the tab  30  and facestock layer  32  into a terminal or mounting portion  30   a  and  32   a,  a connecting or central portion  30   b  and  32   b,  and a terminal or securement portion  30   c  and  32   c.  The facestock layer  32  is extensible and may be formed in any of the above described manners. 
     Release means or coating  38 , such as a silicone coating, as are known in the art, extends along an outer surface  32 ′ of the facestock layer  32 . The other or inner surface  32 ″ of the facestock layer has an adhesive layer  40  extending along its entire length adjacent the portions  30   a,    30   b  and  30   c  of the tab  30 . The adhesive layer  40  has an outer surface  40 ′ and an opposed inner surface  40 ″. The adhesive layer  40  may comprise a known pressure-sensitive adhesive suitable for use in diaper tab applications as described above. 
     One portion of the adhesive layer  40  extending along the terminal or mounting portion  30   a,  on the left as shown in FIG. 3, is exposed to form a factory joint with the diaper outer shell of the diaper  22 . A release means or coating  42 , which may be similar to the release means  38 , extends along the adhesive layer  40 , or more particularly, the outer surface  40 ′ thereof, across the central or connecting portion  30   b  of the tab  30 . Mechanical engagement member  44  is located adjacent the terminal segment  30   c,  the portion of the adhesive layer  40  and mechanical engagement member  44  being coextensive along such terminal or securement portion of the tab  30 . 
     As shown, the mechanical engagement member  44  comprises a plurality of engagement elements  44   a  that project from the facestock layer  32 . The elements  44   a  may be integrally formed with the facestock layer  32 , or they may be separately formed and subsequently attached thereto as a conventional hook and loop fabric. It is also possible to embed separate elements  44   b,    44   c  or  44   d  in the adhesive layer  40  as shown in FIG.  3 . (A variety of such elements are shown in U.S. Pat. Nos. 3,748,701 and 4,169,303.) The elements  44   a - 44   d  extend a sufficient distance beyond the outer surface  40 ′ of the adhesive layer  40  to provide mechanical engagement with a locking or complimentary array of mechanical elements, or with a fibrous material such as a non-woven landing tape or zone, or with a non-woven backsheet of a diaper. 
     The tab  30  provides a known “Z-fold” configuration as particularly shown in FIG.  2 . However, the added advantages of extensibility and combined mechanical/adhesive engagement are provided in accordance with the invention. 
     Referring to FIG. 4, a second aspect of the present invention is illustrated. Accordingly, a diaper tab  50  for use in closure of a diaper  52  is shown. The diaper tab  50  includes a facestock film or member  54  and an adhesive/cohesive layer  56 . The tab  50  is arranged to engage a landing zone tape or member  58  secured to the opposite end of the diaper for closure thereof. The tape  58  includes a cohesive layer  59  carried by a supporting facestock layer  57  adhered to the outer shell of the diaper  52 . 
     The adhesive/cohesive layer  56  includes adhesive portions  56   a  and cohesive portions  56   b.  These portions are shown in an alternating row or strip pattern, however, any pattern may be used. The relative surface areas of the portions  56   a  and  56   b  are not critical, but each should be sufficient to achieve the desired characteristic thereof. For example, a 1:1 surface area ratio is generally satisfactory, but this may vary depending upon the aggressiveness of the pressure-sensitive adhesive, tack of the cohesive and/or the contamination resistance of the cohesive. 
     The adhesive portions  56   a  may be formed of an above described pressure-sensitive adhesive. The cohesive portions may be formed of the cohesive elastomers described in U.S. Pat. No. 5,085,655 to Mann, owned by the assignee herein. Similarly, the cohesive layer  59  of the landing zone tape  58  may also be provided in accordance with the Mann patent. 
     The adhesive/cohesive layer  56  provides the aggressiveness of pressure-sensitive adhesives and the contaminate resistance of cohesives. Also, it should be appreciated that the adhesive portions of the layer  56  allow the tab  50  to be secured to any available surface of a soiled diaper that has been rolled-up for disposal. The adhesive/cohesive layer  56  may be formed using the side-by-side coextrusion process discussed above with respect to the provision of extensible facestock or tab constructions. 
     Referring to FIGS. 5,  6  and  7 , the fourth aspect of the present invention is illustrated in connection with a diaper tab  60  for use in the releasable closure of a diaper  62 . The diaper tab  60  includes a facestock film or member  64  having a plurality of perforations or apertures  66  in aligned rows and columns in a regular array. The tab  60  is arranged to engage a landing zone tape or member  68  secured to the opposite end of the diaper  62  for closure thereof. The tape  68  includes a substrate film  70  having a plurality of upstanding engaging elements  72  arranged in a complementary pattern or array and adapted to be received in the apertures  66  to secure the diaper closed. The substrate film  70  may be secured to the diaper  62  by adhesive or other means known in the art. 
     As best shown in FIG. 6, the facestock film  64  may be provided with a non-planar configuration to better present the apertures  66  for receipt of the elements  72 . For example, the aperture  66  extends in an angulated portion  64   a  of the facestock film  64  which extends at an angle relative to base portion  64   b  of the film  64 . The angulated portion  64   a  extends in a plane that intersects the plane of the base portion  64   b.  Since the major portion of the aperture  66  is within the angulated plane, the aperture is said to be generally contained in the angulated plane even though portions of the aperture extend out of the plane. 
     The film  64  may be heat set by hot rolling to provide the desired non-planar configuration and to effectively sculpture the aperture in the direction of element engagement and locking. The film  64  may be formed of suitable polymer material to provide a substantially nonextensible or an extensible tab as particularly discussed below. 
     The apertures  66  may of circular cross section (prior to heat setting) as shown. The aperture  66  has an opening edge  66   a  including an upper edge portion  66   b  and a lower edge portion  66   c.  The elements  72  project to a height intermediate the upper and lower edge portions. Accordingly for securement or diaper closure, the tab member  60  is initially moved with tension in a lengthwise direction (to the right in FIG. 7) over and past the securement point, the tab member is then moved downwardly to position the base portion  64   b  of the facestock film  64  on the substrate  70  of the landing member  68 . Upon relaxation of the tension, the tab member withdraws slightly to the left as shown in FIG. 7, and the elements  72  are initially received in the apertures  66  adjacent the upper edge portion  66   b  to facilitate engagement. The lower edge portion  66   c  enhances retention of the elements  72 . Further, the apertures  66  may be of key hole shape including a narrowed end portion extending to a relatively wider portion. The elements  72  are initially received in the wider portion of the key hole shaped aperture and then better trapped in the narrow portion of the key hole to improve the security of the closure. This improved entrapment is particularly effective when the film  64  is extensible and tensioned in the closed position. 
     The elements  72  may have any shape that is conveniently snagged or received in the apertures  66  as the tab  60  is pressed against and moved across the landing zone tape  68 . Preferably, the elements  72  comprise discrete non-fibrous members. The elements  72  are shown with a mushroom shape in FIG. 5, the enlarged head operating to maintain engagement within the aperture. In FIG. 7, landing zone tape  68 ′ provides elements  72 ′ having a bowl shape. As illustrated, the elements  72 ,  72 ′ and apertures  66  are sized and arranged to engage in pairs. 
     The number, size and distribution of the apertures  66  and elements  72  are not critical. The number of engaged apertures and elements upon securement may range from one to 500. The major dimensions of the apertures  66  and elements  72  may each range from about 0.005″ to 0.5″. 
     The landing zone tapes  68 ,  68 ′ and/or the elements  72 ,  72 ′ may be formed of any polymer of suitable stiffness or rigidity to assure good mechanical shear strength. For example, polyurethane, nylon, polyethylene and polypropylene are sufficiently rigid. Also, these polymers may be extruded onto a rotating mold to simultaneously form the substrate film and the engaging elements. 
     Referring to FIGS. 8 and 9, a fourth aspect of the invention is illustrated in connection with a diaper tab  80  for use in closure of a diaper  82 . The diaper tab  80  includes a facestock film or member  84  having a plurality of perforations or apertures  86  arranged in a regular array of aligned rows and columns. The tab  80  is arranged to engage a landing zone tape  88  secured to the opposite end of the diaper  82  for closure thereof. The tape  88  includes a substrate film  90  having a plurality of upstanding engaging elements  92  adapted to be received in the apertures  86  to secure the diaper closed. Preferably, the elements  92  comprise discrete non-fibrous members. The substrate film  90  may be secured to the diaper  82  by adhesive or other means known in the art. 
     The apertures  86  in the facestock film  84  substantially provide the latter with an open, mesh type construction. As compared with the tab  60 , the tab  80  is substantially more open, the apertures  86  being relatively larger than the apertures  66 . Although the apertures  86  are shown with a rectangular shape, they may have any configuration. 
     The elements  92  have a mushroom configuration, the mushroom head enhancing interlocking within the apertures  86 . The elements  92  may have any shape that is conveniently received in the apertures  86  as the tab  80  is pressed against and moved across the landing zone tape  88 . 
     The apertures  86  and elements  92  are relatively sized and arranged to engage more than one element in an aperture. In FIG. 9, two elements  92  are received in each aperture  86 . However, three or more elements may be received in a single aperture. The actual size of the apertures and elements may be similar to those last described above. 
     The tab  80  and landing zone tape  88  may be formed of materials similar to those described above in respect to the tab  60  and tape  68 . Also, similar processing techniques may be used to make the tab and tape. 
     Referring to FIGS. 10 and 11, a fastener system  100  includes a diaper tab member  102  deployed for engagement with a landing member  104  to releasably close the diaper  106 . The diaper tab  102  includes a facestock film or member  108  having a pressure-sensitive adhesive layer  110 . The tab  102  may be nonextensible or extensible. The landing member  104  includes a facestock film or member  112  secured to the outer shell of the diaper  106  in a suitable manner such as by pressure-sensitive adhesive layer  114 . 
     The facestock film  108  is clear or transparent and the adhesive layer  110  is tinted to provide it with a suitable color, e.g. a yellow color, which may be viewed through the facestock film  108 . The transparency of the film  108  may be achieved by omission of typical opacifying agents. The coloration of the adhesive layer  110  may be provided by the addition of suitable dyes or pigments to the adhesive composition. 
     The facestock layer  112  of the landing member  104  provides an exposed or outer adherent surface  116  having a color that cooperates with the color of the layer  110  when viewed through the transparent facestock layer  108  to provide a color indication of proper adhesive engagement and diaper closure. To that end, the facestock layer  112  and/or the adherent surface  116  thereof may be colored by conventional dyes or pigments incorporated in the facestock composition during manufacture or later applied to the adherent surface  116 . For example, the adherent surface  116  may be colored blue. 
     The color intensities are selected so that upon placement of the tab  102  and landing member  104  in close overlying relationship characterizing proper or desired adhesive engagement and diaper securement, the tab  102  appears to be green when viewed through the clear facestock film  108 . For example, referring to FIG. 11, the diaper tab  102  and the landing member  104  are shown in cross-section. When secure engagement is provided, the tab  102  assumes a green color when viewed in the direction of the arrow A. 
     As an alternative to color change, the tab  10  may have a hazy or cloudy appearance which becomes clear or transparent upon secure engagement with the landing member  104 . 
     It should be evident that this disclosure is by way of example and that various changes may be made by adding, modifying or eliminating details without departing from the fair scope of the teaching contained in this disclosure. The invention is therefore not limited to particular details of this disclosure except to the extent that the following claims are necessarily so limited.