CA2234100A1 - Dual structured fastener elements - Google Patents

Abstract

A fastener and a method of fastening articles employing the fastener are provided. The fastener includes a fastener (7) element adapted to be mated in an interlocking arrangement to a complementary fastener element (8). The fastener element has a plurality of mating cavities (6). The mating cavities (6) include a mating surface (5) which is adapted to interlockingly engage a mating element (4a, 4b) projecting from the complementary fastener element.

Description

CA 02234l00 l998-04-06 W O 97/13981 PCT~US96/lS93Z
DUAL STRUCTURED FASTENER ELEMENTS

Back~round of the Invention A variety of ways have been devised to fasten articles together. For 5 example, it has been proposed to taper the sides of a shaft so that a head portion con~ietin~ of, for example, a toothbrush or tool, may be ~tt~qch~o~, while perrnitting removal and i,lLelchange ofthe head portion, as disclosed in U.S. Patent Nos.
1,887,913 (Bell), 3,039,340 (Livermont), 3,182,345 (Smith) and 3,369,265 (Halberstadt et al.). Also, intermeshin~ joints have been utilized for connecting in lo woodworking,asdisclosedinU.S.PatentNos. 1,212,262(Rockwell), 1,214,261 (Balbach), 1,342,979 (Beitner) and 1,954,242 (Heppenstall), and in metal working, as disclosed in U.S. Patent Nos. 2,895,753 (Fe..~ ) and 3,000,658 (Sprouse).
Further, inclined or tapered shafts have been utilized for interconnecting the ends of leather washers, as illustrated in U.S. Patent No. 281,760 (Gingras). However, all of the above have utilized a single shaft and, in some in.ct~nces7 either provided protruding elements along the sides or a T-shaped like-end to provide additionalmer.h~nical interference to enhance f~stçnin~
Containers of the type commonly known as "Tupperware" containers (Tupperware is a registered trademark of Kraft, Inc.) and similar containers aredisclosed, for example, in U.S. Patent Nos. 2,487,400 (Tupper), 3,335,774 (Reed), 3,618,802 (Yates, Jr.), 3,730,382 (Heisler), and 3,817,420 (Heisler). The covers of such containers are precisely sized and when mounted, the covers are stretched to cause a tension to be developed in the cover rims between inner and outer ret~ining lip portions to provide mechanical interlocking for closure. A related patent, U.S.
Patent No. 4,819,309 (Bayemer) discloses that the two parts of a fastener may beidentical thereby creating what is referred to as a self-mating fastener.
A number of fasteners ~l~ili7ing a plurality of longit~rlin~lly e~cten~ling rib and groove elements which deform, mechanically interfere and resiliently interlock with each other have also been disclosed. Examples of such fasteners are described inU.S. PatentNos. 2,144,755 (Free-lm~n), 2,558,367 (Madsen), 2,780,261 (Svecedahl), 3,054,434 (Ausnit et al.), 3,173,184 (Ausnit), 3,198,228 (Nato), and 3,633,642 (Segal).

W O 97tl3981 PCT~US9611S932 Other fasteners are based on the use of an adhesive. Examples of f~ten~ors that use adhesives as part of the active closure surface are disclosed in U.S. Patent Nos. 4,699,622 (Toussant et al.), 4,743,242 (Grube et al.), 4,817,816 (Leseman et al.), 4,861,635 (Carpenter et al.), 4,959,265 (Wood et al.), 5,158,557 (Noreen et al.) and 5,221,176 (Battrell et al.).
There are also a number of mechanical fasteners based on the interaction of multiple çng~ging Pl~mçnt~ One group of such fasteners includes the hook-to-hook fastener disclosed in U.S. Patent 2,717,437 (Mestral), the hook-to-loop fastener described in U.S. Patent 3,009,235 (Mestral), and the headed stem or 0 mushroom-to-loop fastener disclosed in U.S. Patent 4,846,815 (Scripps).
Another group of related patents describe fasteners which include functional surfaces with patterns of interlocking elements. The interlocking elements have contoured heads in a variety of shapes which fit into cavities between the base or stem of the complim~nt~ry functional surface of the fastener. Normally these fasteners are self-mating and often the headed portion of the elements is larger in diameter or a cross section than the space between heads on the compliment~ry functional surface. Examples of this type of fastener are illustrated in U.S. Patents 2,499,898 (Anderson), 3,192,589 (Pearson), 3,266,113 (Fl~n~g~n, Jr.), 3,408,705 (Kayser et al.) and 5,097,570 (Gershenson). U.S. Patent 3,899,805, which discloses the use of hollow-headed interacting elements, is a variation of this type of approach. All of these fasteners based on the mech~nical interaction of a multiplicity of elements function by fitting an expanded region of an element on one functional surface into a seat or cavity which is a reduced cross-section or restricted pocket on the complementary functional surface. The joining of this type of fastener is normally associated with a single or double snap as the fastener is engaged.
Another type of meçh~nic~l fastener that is self-mating and has a multiplicity of interrneching solid protrusions is disclosed by U.S. Patent 4,875,259 (Appeldorn). Fasteners of the type described in Appeldorn do not make use of interacting elements with expanded heads. Rather, the bond between the complementary functional surfaces of the fastener is due to frictional forces -CA 02234l00 l998-04-06 W O 97/13981 PCTrUS96/lS932 generated between cont~c.ting surfaces of the intermeching protrusions on each of the functional surfaces. The sides of the intermeshing protrusions consist of optically smooth flats. Examples of other fasteners of this type may be found inU.S. Patents 5,071,363 (Reylek et al.), 5,088,164 (Wilson et al.), 5,113,555 (Wilson et al.), and 5,201,101 (Rouser et al.).
Yet another self-mating fastener which functions by ~ng~ging projections on one functional surface into receptacles on a complem~nt~ry functional surface toform a releasable friction fit is disclosed in U.S. Patent 4,581,892 (Spier). The projections on one surface perforate a web on the second surface and alternate in o rows from one side of the web to the other.
Because of the wide variety of potential applications for fasteners there is a continued dçm~n~ for new fasteners having enhanced pelro.mal1ce with regard to awide variety of factors, e.g., the number of closures, engagement and icPng~gement forces, noise, relative movement between fastener surfaces, washability, resict~nce to soiling or co.,~ tion, and the level of load or shearstress the fastener will support. There is a continued need for the development of f~ctçners having enhanced properties with regard to one or more of these factorsthat will also satisfy requirements concerning ease of m~mlf~ctllre and constraints on cost.
Summary of the Invention The present invention provides a fastener and a method of f~ctPninf~ articles employing the fastener. The f~ctçner in~ des a fastener element and a complem~nt~ry f~ctçner ~.lement The fastener ele.ment and complçm~nt~ry f~et.oner element may either be portions of a single structure or may consist of two separate components. The fastener element inclllclec a polymeric substrate having a plurality of mating cavities which include a first mating surface. A cross-section perpendicular to the first mating surface includes a plurality of first nficlop.~ sions extending from the first mating surface. The mi-,.oplo~ sions may include discontinuous micl uprotl llsions, e.g., discrete microprot, llsions of regular or amorphous shape. In other embodiments of the invention, the W O 97/13981 PCTrUS96/lS932 mic. op, oL. .Isions may include continuous mi~;. Opl .~L. ~Isions, e.g., a ridge ext~n-ling from the sides of a post in a screw thread configuration. Typically, the first mating cavities are defined by ~dj~c~nt first mating elements projecting from the polymeric ~ubsll~le s The complementary fastener element incl~ldlos a polymeric substrate having a plurality of second mating elements projecting therefrom. The second mating elements include a mating surface such that a cross-section perpendicular to thesecond mating surface includes a plurality of second mic. op. .,L. ~Isions e~çn~ing from the second mating surface.
o When the first and second fastener elements are engaged, at least one mating element projecting from the second fastener element is interlockingly retained in a mating cavity defined by adjacent mating elements on the first f~ctçner element. The fastener elements typically may be releasably engaged with each other. This permits the fastener to be used in applications requiring a fastenerwhich can be repeatedly joined and separated.
The fasteners of the present invention have a wide assortment of potential applications, such as a fastener on a reclosable container, in place of a button or zipper on clothing or to attach an object to a di.c~imil~r article. The fasteners allow articles to be fastened in a variety of positions and may not require any particular ~lignm~nt prior to connection. The present invention also permits the construction of fasteners having a direct, continuous relationship between engagement and eng~gement forces.

Brief Description of the Drawin~s Figure 1 shows cross-sectional view of a fastener element of the present invention.
Figure 2A shows a cross-sectional view of first and second f~tçnçr ~lçmçnt.c of the type depicted in Figure 1 just after being brought into contact.
Figure 2B shows a cross-sectional view of first and second fastener elements of the type depicted in Figure 1 interlockingly engaged.

CA 02234l00 l998-04-06 W O 97/13981 . PCTrUS96/lS932 Figure 3 shows a cross-sectional view of a portion of an alternate embodiment of a fastener element of the present invention.
Figure 4 shows a cross-sectional view of a portion of an alternate embodiment of a f~t~n~r element of the present invention.
s Figure 5 shows a cross-sectional view of a portion of a f~etçnPr of thepresent invention. The cross-sectional view shows interlocking engaged mating ~1~m~nt.c from first and second fastener elements.
Figure 6 shows a cross-sectional view of a portion of an alternate embodiment of a fastener element of the present invention which includes hollow o posts.
Figure 7 shows a cross-sectional view of a portion of an alternate embodiment of a fastener element of the present invention which includes hollow posts having the recesses filled with a polymeric material.
Figure 8 shows a cross-sectional view of a portion of an alternate embodiment of a fastener element of the present invention which includes a plurality of dual structured mating elements on one face and a "slotted cup" fastener component on the opposite face.
Figure 9 shows a cross-sectional view of a portion of an alternate embodiment of a f~t.?n~r element of the present invention which incl~ldes a plurality of dual structured mating eJçnnents on one face and an adhesive layer covered by a release liner on the opposite face.
Figure 10 shows a perspective view of a mating element of an alternate embodiment of the present invention.
Figure 11 shows a top view of a portion of an alternate embodiment of a f~et~ner element ofthe present invention which includes mating elements ofthe type depicted in Figure 10.
Figure 12 is an electron micrograph (18 X magnification) of a portion of a f~t~:n~r element of an alternate embodiment ofthe invention which in~ ldes a square array of cylindrical posts.

W O 97/13981 PCTrUS96/15932 Figure 13 is an electron micrograph (18 X magnification) of a portion of a fastener element of an alternate embodiment of the invention which includes a hexagonal array of screw threaded posts.
Figure 14 depicts a cross sectional view of a portion of a master used to prepare a microstructured polymeric substrate of the present invention.
Figure 15 is an electron micrograph of a cross-sectional view of portions of two fastener elements of the present invention prior to their being brought intoengagement.
Figure 16 is an electron micrograph of a cross-sectional view of portions of lo the two fastener elements of Figure 15 in interlocking engagement.
Figure 17 is an electron micrograph (22 X magnification) of a portion of a fastener element of an alternate embodiment of the present invention which incl~ldes a square array of screw-threaded posts.
Figure 18 is an electron micrograph (22 X magnification) of a portion of a 1S fastener element of an alternate embodiment of the present invention which incllldes a square array of screw-threaded posts having four flat faces uniformly uniformly disposed around the circumference of each post.

Detailed Description of the Invention Figure l depicts a cross-sectional view of a portion of a dual structured fastener el~.mçnt of the present invention. The fastener element consists of a unitary polymeric substrate l which includes a base 2 and solid mating elements 3 projecting from the base. The cross-sectional view shows microprotrusions 4 PYt~n~ing from the sides ("mating surfaces") 5 of mating elements 3. ~rlj~cPnt 2s mating elements 3a, 3b define a mating cavity 6 which is capable of receiving and interlockingly eng~ginp: a suitably sized mating element projecting from a second ("complemcl.~a,y") fastener element.
Figures 2A and 2B schematically depict the interaction between two like fastener elements as they are brought into contact with each other. In Figure 2A, the two fastener elements 7, 8 have been pressed together such that only a fraction of the micl uproll usions 4a, 4b on each of the mating surfaces are interlockingly CA 02234l00 l998-04-06 W O 97/13981 PCTrUS96/15932 çng~g.orl As additional force is exerted on fastener elements 7, 8, mating element 9 projecting from second f~t~nçr element 7 is driven deeper into mating cavity 6, which is defined by ~ cent mating elements 3a, 3b projecting from first fi~t~nf.r elPmP,nt 8. The force required to ~1ieçnp;~ge fasteners of the type shown in Figures s 2A and 2B is typically proportional to the engagement force applied to the f~etçner Application of a relatively moderate engagement force results in projecting element 9 only being partially pressed into mating cavity 6 (see e.g., Figure 2A). As additional force is applied to the f~etçnçr ~l~mçnt.~, mating element 9 is forced deeper into mating cavity 6 and the number of microprotrusions 4a on mating 0 surfaces 10 which become interlockingly engaged with microprotrusions 4b on mating surfaces 11 increases. The force required to disengage fastener elements 7 and 8 from each other thus correspondingly increases.
The mating elements projecting from the present fastener elements may have a wide variety of shapes and orientations. The mating elements may include any 1S one of a number of regular geometric shapes, such as tri~n~ r pyramids, posts having a regular polygonal cross-section or fructoconical posts. Alternatively, the mating elemçntc may include randomly oriented projections having an amorphous shape. Other suitable examples of mating elements which may be present on the f~t~nçr elements ofthe invention include spherical or spheroidal shapes.
The size and shape of the mic, Opl oL~ ~Isions will vary somewhat as a function of the draft angle of the mating elements. In general, in order to be capable ofinterlocking eng~gemP~nt, mating elements whose sides have a larger draft angle require somewhat larger miclol)l~o~ sions. The present mating elements typicallyinclude at least one side having a relatively steep draft. For example, mating 2s elemçntc having a draft of less than about 30~ (with respect to a vector perpendicular to the major surface of the polymeric substrate) may be employed.
Fastener elçmpnt~ inclll(ling mating elements having a sidewall which is quite close to being vertical, i.e., having a draft of less than about 10~, are included within the present invention.
The size and positioning of the mating PlçmPnts projecting from a polymeric film may be chosen such that a second polymeric film having similar features (the W O 97/13981 PCT~US96/lS932 "complçmPnt~ry fastener element") is capable of being brought into interlocking engagement. The mating elements are typically oriented such that ~dj~cent matingelements on the fastener element define a mating cavity which is capable of ~ interlockingly Png~in~ a mating element projecting from a second fastener element.
s This may be achieved by a f~ctPnçr element which has a randomly arrayed set of projecting mating elements. More typically, however, the present f~ctçnçr elements include some form of regularly arrayed mating elements. For example, the mating elements may include a regular array of parallel ridges 20 of the type shown in Figure 3. Alternatively, the present mating elements may include a regular array of o discontinuous mating elements, e.g., a square array of tapered posts 25 (as shown in Figure 4) or a hexagonal array of rod-like posts 50 (as shown in Figure 5).
The fastener elements may be self-mating, i.e., a fastener element may be capable of interlockingly Png~ging a second fastener element having an identical or substantially similar structure. It is not necessary, however, that the fasteners of the 1S present invention consist of two substantially similar fastener elements. Rather, the present fasteners are only required to include a first fastener element having amating cavity which is capable of interlockingly ret~inin~ a mating element ~ projecting from a second fastener element. For example, the present invention incl~ld~e fasteners in which the first fastener element has a parallel array of ridge-like elements having a plurality of microscopic ridges projecting from their sides and the second fastener element has an appl opl iately spaced square array of trunc~ted polygon-shaped elements (e.g., truncated square pyramids).
As noted above, the mating cavities on the first fastener element are typically defined by adjacent mating elements projecting from the first f~ctenerelement. The portions of the outer surfaces of the projecting elements defining a mating cavity which come into contact with a second fastener element are referred to as "mating surfaces." Correspondingly, the surfaces ofthe mating elements projecting from the second fastener element which come into contact with the first fastener element also serve as "mating surfaces."
The shape and orientation of the mating elements on the first fastener element are not necessarily the same as the shape and orientation of the mating CA 02234l00 l998-04-06 W O 97/13981 PCTrUS96/15932 elements on the second f~t~ner ~lement For example, the first f~tçn~r element may include ridge-like mating elements 20 having a plurality of microscopic ridges 21 projecting from their sides (see e.g., Figure 3). The mating elements 20 of such a fastener element define a plurality of grooved mating cavities 22. In one s embodiment of the present invention, a fastener may include two such groovedf~etçner elements. Alternatively, the present fastener may include one such grooved fastener element and a second ("complementary") fastener element which has a di~,~ configuration. For example, the second fastener element may include a plurality of discontinuous tapered posts 25 ("mating elements") which have a 0 plurality of ridge-like micl opl o~ sions 26 projecting from at least one sidewall (see e.g., Figure 4). The spacing and orientation of the tapered posts on the second fastener element need not be such that the posts are capable of interlockingly eng~ging every ridged groove ("mating cavity") on the first fastener element.
Rather, the size and orientation of the tapered posts on the second fastener element lS need only be such that a sufflcient number of posts interact with the corresponding ridged grooves on the first fastener element to achieve interlocking engagement of the two fastener elements. For example, a fastener element of the type shown in Figure 4 may have tapered posts 25 oriented such that the posts are only capable of being interlockingly engaged in every second, third or fourth groove-like matingcavity 22 of a fastener element of the type shown in Figure 3. Similarly, the height of the mating elçm~ntc on the first and second fastener elements of the present fasteners need not be identical so long as a sufficient number of mating elements on the two fastener elements are capable of being interlockingly engaged in order to hold the two f~tpner elements together.
The present f~t~ner elements typically may be brought into interlocking engagement at least once without the microprotrusions on either the f~t~n~r element or the complçm~ont~ry f~ctener being destroyed or having their shape s~lbst~nti~lly altered. Preferably, the mic~uploLI~lsions are capable of being subjected to a number of engagement-disengagement cycles without being destroyed or subst~nti~lly degraded. The number of cycles that a particular fastener will be capable of withct~n-ling without the mi-"oplo~ sions suffering substantial W O 97/13981 PCT~US96/lS932 degradation will depend on the intended use for the f~t~nçr. For some applications, it is sufflcient if the mating elements can survive being brought into interlocking engagement a single time. If the f~tençr elements are intçnded to be employed as a closure element on an article of clothing, the fastener elements are s preferably sufficiently durable to be able to with~t~nd hundreds or even thousands of engagement~ çng~gement cycles. Other applications may require fastener elements which are capable of being subjected to 5, 10 or 25 engagement-t1i~çng~g~m~nt cycles.
The microprotrusions on the mating surfaces of the present fastener 10 elements may have a wide variety of shapes and may be arranged in a random and/or ordered array. The microprotrusions may be discontinuous, i.e., may consist of a plurality of discrete microscopic projections extending from the mating surfaces. For example, the microprotrusions may include a plurality of discrete mounds, posts, cones, pyramids, cylinders, partial spheres or spheroids, tnlnc~ted 15 cones ("fructoconical"), tn~nc~ted pyramids, and/or other fructopolygonal shapes.
In one embodiment of the invention, the microprotrusions include a plurality of small, random microprotrusions which are inverted replicas of the cells in the surface of a closed cell polymeric foam. Alternatively, the microprotnusions may be continuous in nature, e.g., a plurality of ridges or a single continuous ridge 20 extending from the sides of a mating element in a screw thread configuration.The dimensions of the microprotnusions are typically small enough to leave the overall form of the mating elements substantially unaltered. For example, continuous microprotnusions typically have a maximum height or width of no more than about 400 ~lm. Similarly, discontinuous microprotnusions typically have a 2s maximum height of no more than about 400~1m and a maximum width of no more than about 400 llm. Preferably, discontinuous microp~ o~ sions have a maximum height of no more than about 25011m and a m~ximllm width of no more than about 250,um. Continuous microprotnusions preferably have a maximum dimension of no more than about 250~m. The discontinuous microprotnusions typically have a 30 miniml-m height and width of at least about 1 011m and preferably at least about 25~1m. Similarly, where the micloplol~usions are continuous in nature, the height W O 97tl3981 PCTrUS96/lS932 and width ofthe micloplo~ sions are typically at least about lOIlm and preferably at least about 2511m.
The present fastener elements may be produced by a variety of methods.
For example, a f~tçnPr element of the type shown in Figure 6 may be formed by s embossing a softened thermoplastic polymeric film in a manner that results in an array of hollow mating elements 30 projecting from one surface of the film 33 and ~imlllt~neously generating a plurality of micl opro~ sions 31 exten~ing from theouter surface of the mating elements. This may be accomplished by passing the thermoplastic film through a nip which includes an embossing roll and a chill roll o covered by a layer of resilient material. The resilient material is typically a foam mate~rial, e.g., a closed cell polymeric foam (such as LS1525 polyurethane foam;available from EAR Specialty Composites Corporation, Tntli~n~polis, IN). The exposed cells at the surface of the closed cell foam act as microscopic molds for the formation of microprotrusions on the thermoplastic film.
When the softened thermoplastic polymeric film passes through the nip and contacts the embossing and chill rolls, hollow mating elements 30 projecting from the polymeric film are formed. As this occurs, the softened thermoplastic polymeric film is also thrust into intim~te contact with the foam surface of resilient roll by the pressure in the nip. This forces the softened polymeric material to conform to the contours of the foam. The softened polymer is driven into any recesses, pores orcrevices defined by the microscopic cells present on the foam surface, thereby generating microscopic protrusions 31 ("microploL~.Isions") on the polymeric surface in contact with the resilient surface. The micloproL-~lsions formed on the polymeric surface are typically inverted replicas of corresponding microscopic cells.
Contact between the foam surface and the polymeric material is m~int~ined for sufficient time to allow the polymer to solidify to a sufficient degree such that the microprotrusions retain their shape as the microstructured polymeric film is pulled away from the resilient surface. This may be accomplished, for example, by m~ )g the temperature of the chill roll below the softening point of the thermoplastic polymeric material. The overall result is the formation of mi~,lupluLI~lsions on the portions ofthe polymeric material in contact with the foam.

W O 97/13981 PCT~US96/lS932 The res--lting polymeric film 33 has a plurality of projecting hollow mating elements 30 having a hollow core 32 (see e.g., Figure 6). The outer surface ofthe mating elements 30 incl~ldes a plurality ofthe microprotrusions 31.
Where a foam material is employed as the chill roll cover, a substantial s number ofthe micloploLIllsions generated may be undercut-shaped. As used herein, the term "undercut-shaped" is defined as a shape having a cross-sectional surface area which increases and then typically decreases along a perpendicular vector away from the polymer surface. The cross-sectional surface area is measured in a plane perpendicular to the surface with respect to which the o undercut-shaped mic,oplo~ sions in question are positioned. Because ofthe manner in which such undercut-shaped microprotrusions are formed, the microprotrusions are substantially inverted replicas of the cells in the foam surface of the chill roll cover.
In another embodiment of the invention, a unitary polymeric fastener lS element which incl~ldes solid, mating elements projecting from a sheet of polymeric material (see e.g., Figure 1) may be formed by pressing a flowable polymeric material into a resilient mold (e.g., a silicone rubber mold). The resilient mold typically has a plurality of macroscopic depressions which include microdepressions extPn~ling from their sides into the mold. While the polymeric material is in intim~te contact with the mold, it is solidified to a sufficient degree to allow the polymeric material to retain its shape as the polymer is pulled out of the mold. The res--ltin~
fastener element has a plurality of solid mating elements projecting from the element. At least one outer surface of the mating elements incl~des a plurality of microprotrusions which are inverted replicas of the microdepressions in the mold.
2s In a preferred embodiment of the invention, a resilient mold of the type described above may be mounted as the cover on the chill roll of a nip. Extrusion of a flowable polymeric material, such as a softened thermoplastic polymer, into the nip results in the formation of a polymeric film having solid microstructured projecting mating elements which are inverted replicas of the depressions in theresilient mold.

W O 97/13981 PCTrUS9611S932 A wide variety of polymers may be used to produce the fastener elements of the present invention. Typically the polymeric material is thermoplastic although other polymeric materials capable of being processed in a flowable state, such as a plastisol or a B-staged thermoset polymer, may also be readily employed. The s material the mating elements are formed from as well as the shape of the mic.oplu~ sions and mating element sidewalls, infl~len~es the agressiveness withwhich a fastener engages. Depending on the fastener design and the nature of thedi~en~gement forces it is subjected to, the fastener may optimally be formed from either a high durometer or low durometer (e.g., circa 50 durometer) polymeric 0 material. For example, a fastener inchl~ing fastener elements having longit~rlin~l grooved ribs which is subjected to a lateral shear force is preferably formed from a relatively high durometer polymeric material (e.g., about 90-100 durometer).
Suitable polymeric materials used to forrn the present fastener elements can be formed into mating elements having mi.,l.,ploll.lsions which are capable of substantially m~int~ining their structural integrity when subjected to the shearing forces generated when two of the present fastener elements are interlockingly engaged. The polymeric materials must be sufficiently durable to m~int~in the structural integrity of the microprotrusions through the number of engagement-eng~gement cycles required by the int~n-led use of the f~tçner. Some applications merely require a fastener having mating elements and micl Opl Otl ~lsions capable of subst~nti~lly s-lst~ining their structure through a single engagement of the fastener elements. Other uses require fastener elements durable enough to with~t~nd a large number of engagement-~ eng~gement cycles without structural failure.
In addition to being sufficiently durable, the microploll~lsions and/or mating elements on at least one of the fastener elements must be capable of sufficiently deforming to allow the microprotrusions to be brought into interlocking çng~g~ment The derol l~ ion that occurs during the engagement process is elasticor anelastic but not plastic. In other words, the microprotrusions and/or matingelements deform in a manner such that the structure is subst~nti~lly ~ ed following the completion of the engagement and/or ~lisP~gement process.

CA 02234l00 l998-04-06 W O 97tl3981 PCT~US96/15932 Examples of suitable thermoplastic polymeric materials which may be employed to produce the present fastener elements include polyolefins such as polypropylene, polyethylene, and polypropylene/polyethylene copolymers. Blends of polypropylene and/or polyethylene, such as a high/low molecular weight s polyethylene blend (e.g., HostalloyTM 731; Hoechst CPI~n~osç~ Somerville, N.J.), are also suitable for use in the present invention. Other suitable thermoplastic polymers include polyvinyl chloride (PVC), polyamides such as a nylon (e.g., nylon 6, nylon 6,6, or nylon 6,9), polystyrene, and polyesters. Olefin copolymers such as ethy]ene/vinyl acetate copolymers or copolymers of an olefin and an a,b-unsaturated 0 acid (e.g., an ethylene/methacrylic acid copolymer reacted with metal salts to confer ionic character; available from E.I. du Pont de Nemours & Co., Inc. as SurlynTM
8527) may also be employed in the present invention. Resilient polymeric materials such as a silicone rubber, thermoplastic elastomers (e.g., KratonT~5), resilientpolyurethanes, and plasticized PVC may also be used to form the fastener elements 5 ofthe invention. In a pr~relled embodiment, the polymeric material includes a polyolefin.
The present fastener elements may also be formed from a thermoplastic polymer in the form of a plastisol. The plastisol inchldes a dispersion of thermoplastic resin particles (e.g., polyvinyl chloride resin particles) in a pl~tici7er 20 and may also include a volatile organic solvent. Examples of suitable plastisols which may be used to produce the present fastener elements include vinyl plastisols such as #D1902-50 Black and #D1902-78 White available from Plast-O-Meric, Inc.
(W~lkç~h~, WI).
Depending on the structural features and the type of polymeric material 25 employed, the deformation during engagement/ li~çng~gement may occur in one of a number of modes. At one extreme~ all of the dero- I-,aLion that occurs as fastener elements are brought into engagement is localized entirely within the microprotrusions while the body of the mating elements remains largely undistorted.
This may occur where the microprotrusions are formed from a sufficiently resilient 30 material. The dero- .--~lion may also be almost totally confined to the microprotrusions where solid mating elements are formed from a rigid polymeric W O 97113981 PCTrUS96/lS932 material. In this case, the dimensions of the micl op- Utl ,lsions permit them to be flexed in a manner akin to that of a leaf spring. Alternatively, the micl Opl o~ sions may be of a material and dimensions such that the mic- op. uL. .lsions are essçnti~lly undeformed during engagement and the necess~. y flexibility is derived entirely from 5 the ability of the mating ~l.omçnt bodies to deform. This can occur where the mating elements consist of hollow projections formed by embossing a thin film ofrigid polymeric material. The hollow inner portion of the embossed f~tçnçr element may be at least partially filled with a resilient material. This allows the body ofthe mating element to flex even if the miclul)lo~ sions remain subst~nti~lly 0 undeformed during engagement of the fastener element. In many instances, however, both the miclupl otl ~Isions and the body of the mating element are deformed to some degree as the fastener element is engaged.
Fastener elements which permit a requisite degree of deformation may have one of a number of related structures. For example, the mating elements may 15 include hollow structures projecting from the surface of the fastener element.
Where the f~ctençr elements are formed as a unitary polymeric structure and include solid mating elements, rigid polymeric materials such as polyethylene, polypropylene or copolymers which include ethylene or propylene may be employed. Other suitable polymeric materials which may be employed to make 20 unitary f~tçnçr elements having solid mating elements include polyamides, polyesters, PVC, polystyrenes, and polycarbonates. The polymeric materials used to form solid mating elements are sufficiently rigid to provide structural integrity to the mating elements. The polymeric material must, however, not be so brittle that the microprotrusions are sheared offwhen two fastener elemçnts are brought into 25 interlocking engagement.
The present fastener elements need not have a unitary polymeric structure.
Rather, the fastener elements of the present invention may be formed from a male-female embossed polymer film having micl opl o~ sions on the male surface of theembossed film. The film 40 may be embossed to create a plurality of hollow 30 projecting mating elements 41 (see e.g., Figure 7). The hollow cores ofthe mating elemçnt~ 41 may be filled with a polymeric material 42 to strength~n and support W O 97/13981 PCTrUS96/lS932 the mating elements 41 and alter their flexibility and resiliency. The overall resiliency of the mating elements on at least one fastener element of a fastener must allow the outer contour defined by microplo~ sions 43 to deform sufficiently without be destroyed to enable a complementary mating element to be pressed intomating cavity 44 such that mic~oplot"lsions on the mating surfaces in contact are interlockingly engaged. Typically, mating elements on both fastener elements of a fastener are resilient and deform elastically or anelastically during engagement. In order to be achieve interlocking engagement, however, only the outer contour defined by the micl ~,p, ULl usions of one fastener element a pair need be capable of elastic or anelastic deformation. For example, the present invention includes fasteners where one fastener element includes mating elements with microprotrusions formed from a resilient polymeric material while the micloplol"lsions on the mating elements ofthe complementary fastener element areformed from a rigid polymeric material.
The properties of the present fastener elements can be tailored by applop,iate selection of the polymer used to form the hollow mating elements andthe polymer used to fill the hollow elements. For example, the hollow mating element 41 and the mic,oplo~ sions thereon 43 may be formed from a relatively rigid polymeric material such as a polyolefin, an olefin copolymer, a polyamide, a polyester, PVC, a polystyrene, or a polycarbonate. Thermoset polymeric materialssuch as an epoxy may also be employed as the relatively rigid material. Fastenerelements of this type typically include a relatively resilient polymer, such as a silicone rubber or a thermoplastic elastomer, at least partially filling the cores of the mating elements. The presence of the resilient material 42 in the core allows such mating elements to deform sufficiently to be placed in interlocking engagement with a second fastener element, while the rigid polymer which makes up the hollow outer shell confers structural integrity and durability on the mating elements.
In another embodiment of the invention, the fastener elements may include hollow mating elements formed from a relatively resilient polymeric material, such as a silicone rubber, a resilient polyurethane, a plasticized PVC or a thermoplastic elastomer. Fastener elements of this type may have a hollow core which is filled CA 02234l00 l998-04-06 W O 97/13981 PCTrUS96/lS932 with a relatively rigid polymeric material. To produce fastener elements of this type the hollow mating elements and the microprotrusions thereon are formed from a resilient polymer having sufficient structural integrity to allow the mating elements to withct~n~i the desired number of engagement-rlic~ng~gement cycles. Polyolefins s and epoxies are examples of polymeric materials having the requisite rigidity to be employed as filler in the hollow core of the fastener elements.
The present fastener elements may optionally include an additional att~çhm~nt component on a face other than the surface which includes the dual structured mating elements. The att~chment component permits the f~t~ner 10 element to be affixed to an article such as a wall, a diaper, a piece of sheet metal, a bulletin board, a container or an article of clothing. The ~tt~chment component may include a mechanical fastener element, e.g., a "slotted cup" attachment component 82 of the type shown in Figure 8. The fastener element illustrated in Figure 8 incl~ldes a plurality of threaded posts 81 on one side and two "slotted cup"
15 projections 82 on the opposite side. Alternatively, a fastener element may have an att~chment component which includes a layer of adhesive. For example, the f~et~n~r element may have a plurality of threaded posts on one face and a layer of adhesive on the opposite face (see e.g., Fig,ures 7 and 9). The adhesive backinglayer 45, 92 on the fastener elements depicted in Figures 7 and 9 allows the fastener 20 element to be affixed to another object. For storage purposes, adhesive backed fastener elementc are typically produced with a removable liner 93 covering the adhesive layer (see, Figure 9). Fastener elements of this type may be employed as a tape substitute, a diaper closure or the like.
While the outer surface of the present mating elements may be entirely 25 covered with mi~;loplo~ sions, this is not a requirement. The micloplo~ sionsneed only be present on at least one surface of a mating element which comes into contact with a mating surface bearing micloplu~ sions on a second mating elementwhen two fastener elements are engaged. For example, the mating element 60 illustrated in Figure 10 only has microprotrusions 62 on the four mating surfaces 61 30 at its corners. The l e~ g surfaces 63 on the sides of mating element 60 neednot have any microstructure and may even be optically smooth. A fastener element CA 02234l00 l998-04-06 W O 97/13981 PCTrUS96/15932 may be formed from a polymeric substrate having a plurality of such mating elements 70 oriented in a square array (see e.g., Figure 11). The mating elements 70 need only have microprotrusions on one or more of the surfaces 72 which face the mating cavity defined by four ~ cçnt mating elements 70. When a mating 5 .ol~mP~t 71 from a second fastener element is pressed into the mating cavity, the interaction between the micl opl c,ll ~Isions on the two sets of mating surfaces is sufficient to interlockingly engage the two fastener elements.
The invention is further characterized by the following examples. These examples are not meant to limit the scope of the invention as set forth in the lo foregoing description. Variations within the concepts of the invention will be apparent to those skilled in the art.

CA 02234l00 l998-04-06 W O 97/13981 PCTrUS96/lS932 Example 1 The dual structured fastener element of this example was prepared starting from a master (which had the configuration of the f~tener element). A resilient mold was then made of the master and the fastener element was formed from the s resilient mold.
The master was produced from a flat plate tapped with holes for an 0-80 UNF series clesi~n~tion screw (outside thread ~i~meter of 1.5 mm and inside rii~met~r of 1.3 mm). The holes were placed in a hexagonal array with hole to hole spacing of 2.4 mm and row to row spacing of 2.1 mm. The 0-80 screws were 10 threaded into the plate so that approximately 6 threads showed on the non-head side (i.e., threaded posts about 2.1 mm in height projected from the flat plate).
A patterned silicone rubber mold was then prepared of the above master by applying an approxil"a~ely 5 mm thick coating of uncured silicone rubber (SilasticTM
brand J-RTV silicone rubber; available from Dow Corning Corporation, Midland, 5 MI) over the surface cont~ining the threaded posts. The rubber was cured at 67~C
for one hour and then removed from the master to provide a resilient mold. The mold had a hexagonal pattern of threaded depressions which were inverted replicas ~ of the threaded posts projecting from the surface of the master. The depressions were about 2.1 mm deep with threaded grooves (circa 0.2 mm deep) on the sides of20 the depressions.
The rubber mold was placed on a hot plate at 21 6~C and several layers of 152 llm thick polyethylene film (formed from DOWEXTM 2047A; available from Dow Chemical Company, Midland, MI) were placed on top of the mold. A layer of 38 ~lm thick KaptonTM film (polyimide film available from E.I. duPont de Nemours25 and Company Incorporated, Wilmington, DE) was placed on top of the polyethylene. The polyethylene was allow to melt (5 to 10 mimltes) and then pressed into the depressions in the mold. Af'ter the polyethylene had cooled to a sufficient degree to allow the threaded posts to retain their shape, the polyethylene fastener element was removed from the mold and the KaptonTM film was removed.
30 The resl-lting fastener element was a polyethylene film having 2.1 mm high threaded posts projecting from one major face of the film (see Figure 1). The threads CA 02234l00 l998-04-06 W O 97/13981 PCTrUS96/15932 extended about 0.2 mm out from the sides of the posts. If the faces cont~ining the threaded posts of two such polyethylene fastener elements were pressed together,the fastener elen Pnte formed a self-mating fastener.

Example 2 A fastener element having a dual structured portion (hexagonal array of threaded posts) on one major face was made in a manner substantially identical to that described in Example 1, except that after the polyethylene was pressed into the depressions in the resilient mold, the KaptonTM layer was removed and the lo polyethylene was left on the hot plate in a molten state to form "Segment A" of a fastener.
A fastener component having a "slotted cup" configuration was formed on the opposite face of the fastener element according to the following procedure.
This mechanical fastener consisted of two "slotted cup" projections designed to 1~ lock into two 8 mm diameter holes. A silicone rubber master mold was formed from two "slotted cup" projections (#SJ3747, 3M, St. Paul, MN) according to the procedure described in Example 1 except that an approximately 7.5 mm thick coating of uncured silicone rubber was applied to the two "slotted cup" projections.
The "slotted cup" master mold was placed on a hot plate at 216~C, several layers of 152 ~lm thick polyethylene film (as per Example 1) were placed on top of the mold and a layer of 38 ~lm thick KaptonlM film was placed on top of the polyethylene. The polyethylene was allowed to melt (5 to 10 min~ltes) and then pressed into the holes in the mold and the KaptonTM film was removed from the top ofthe polyethylene to form "Segment B" of a fastener.
2~ Segments A and B were then joined such that the unmolded faces of the two polyethylene layers were allowed to bond in a molten state. The two segments were m~int~ined in contact while in a molten state for 5 to 10 minutes and then the entire polymeric assembly was moved of~the hot plate and allowed to cool. The polyethylene fastener element was removed from the silicone rubber molds as a unitary polymeric assembly having a plurality of threaded mating elements projecting from one side and a "slotted cup" fastener projecting from the opposite CA 02234l00 l998-04-06 W O 97/13981 PCTrUS96/15932 side (see Figure 8). The polymeric assembly was capable of being mechanically f~ctçned on either or both sides.

Example 3 s A self mating fastener element was made by passing molten polypropylene(formed from DS7C50; available from Shell Chemical Co., Houston, TX) through a rlip where the polypropylene was pressed between a metal tool and a chill roll covered with two 3.2 mm thick sheets of a closed-cell polyurethane foam (see description below). The metal tool had a hexagonal close packed array of 0 projecting circular posts (1.0 mm in diameter, 1.0 mm in height) which were spaced 1.8 mm on center. This produced a male-female embossed polypropylene film having large hollow posts (I mm in height, 1 mm in average diameter) projecting from one face ofthe film ("male mating surface") in a hexagonal array (1.8 mm oncenters). The male surface of the embossed polypropylene film had a secondary structure consisting of small, random microprotrusions, which were inverted replicas of the cells in the surface of the foam sheet.
The polyurethane foam used as the chill roll cover was prepared as generally described in U.S. Pat. Nos. 3,772,224 (Marlin et. al.) and 3,849,156 (Marlin et. al).
The foam was prepared from a four component mixture (A-D), the composition of which were as follows:
Part A - 100 parts of a polyol mixture consisting of Niax 24-32 (97.77 parts) and Niax E-434 (2.23 parts), polyether polyols (available from Arco Chemical Co., Newton Square, PA) dipropylene glycol (9.18 parts per hundred parts (php) polyol; fragrance grade), Niax LC-5615 (3.74 php, a nickel catalyst composition available from OSI Specialities, Lisle IL), min--m trihydrate filler (54.59 php, Aloca C-331, available from minllm Company of Arnerica, Bauxite, AR), and Hostaflam AP 442 flame retardant (16.38 php, available from Hoechst Cel~nese Corp., Charlotte, NC);
Part B - 37.39 php of an isocyanate mixture consisting of 4,4'-diphenylmeth~ne diisocyanate and a modified 4,4'-diphenylmeth~ne W O 97/13981 PCT~US96/15932 diisocyanate (Rubinate 1920 available from ICI, Rubicon Chemicals, Geismer, LA);
Part C - 4.77 php of a 70.9% (w/w) solution of a silicone surfactant (L
5614, available from OSI Specialities) in a polyether glycol (Niax E-351, s available from Arco Chemical Co.); and Part D - 6.71 php of an approximately 8% solids (w/w) dispersion of carbon black (Product No. 1607029, available from Spectrum Colors, Minneapolis, MN) in polyether glycol (Niax E-351).
Separate feed streams of the four components were pumped into a 90 mm 0 dual head Oakes Frother (available from ET Oakes Corp., Hauppauge, NY) through an entrance manifold attached to the frother. The mixture was frothed byinjecting high purity nitrogen through a capillary tube located at the entrance to the frother. The frothed mixture was processed through the frother at a mixing speedof 800 rpm and a discharge pressure of about 0.55 MPa and dispensed from an 15 approximately 2.6 m x 1.3 cm hose onto a polyester film and spread over the film using a knife coater (2.4 mm gap). The foam was cured by passage through a 3 chambered 13.7 m forced air oven at a line speed of 1.5-1.8 m/minute. The first chamber was ...~ ed at 135~C. The second and third chambers were m~int~ined at 154~C.
When the embossed polypropylene film was folded back onto itself such that two portions of the male mating surface were brought into cont~ct, the projecting elementc interlockingly engaged. After a number of engagement-~isPng~gement cycles, the fastener element would no longer lockingly engage with itself.
Ex~min~tion of the male surface of the film under an optical microscope revealed2s that the small protrusions on the sides of the posts had been fl~ttçnec~ This suggests that the interactions of the secondary structure (small, random protrusions) are nçcess~ry in order for the interlocking engagement of the posts.

Example 4 The embossed polypropylene film of Example 3 was coated on the female side with a silicone rubber (SilasticT~' brand E-RTV silicone rubber; available from W O 97/13981 ' PCTrUS96/15932 Dow Corning Corporation, Midland, MI) such that only the recesses in the female side of the posts were filled with silicone rubber. The initial engagement-~lief~,ng~gement forces required with the silicone rubber-filled f~et~ner PlemP~lt appeal ed to be higher than those for the f~etçner ~lenn~nt of Example 3. However, 5 after a number of cycles the small protrusions on the sides of the posts fl~ttçne~1, as with the f~etçn~r elemPnt described in Example 3, and the f~etener element ceased to interlockingly engage with itself.

Example 5 lo A self-mating fastener element was made by coating the patterned silicone rubber mold of Example 1 with a mixture of KratonTM G1652 (available from Shell Chemical Co., Houston, TX) and toluene at 33% solids. As the toluene evaporated, a continuous KratonTM film covering the threads and the land area between the threaded depressions was formed. The resnlting resilient KratonTM film lS was a replica of the mold and had a hexagonal pattern of 2.1 mm high hollow, threaded posts. The hollow posts were filled with an epoxy resin (a 5: 1 mixture of Epo-KwikTM Resin No. 20-8136-128 and Epo-KwiklM Hardener No. 20-8138-032;
~ available from Buehler, Lake Bluff, IL) which was allowed to harden. When the faces cont~ining the threaded posts of two such f~etçnçr elements were pressed 20 together, the f~etçner elements interlockingly Png~ged The engaged fastener elements were dieçng~ged and reengaged a number of times demonstrating the fastener elements having resilient hollow posts filled with a rigid material can form a releasably engageable self-mating fastener.

2s Example 6 A fastener Plemçnt having a square array of microstructured posts on one major face was made in a manner subsf~nti~lly identical to that described in Example 1, except that a di~. ~ master was used to form the rubber mold. As in Example 1, the master was produced from a flat plate tapped with holes for 0-80 UNF series design~tion screws placed in a square lattice array with hole to holespacing of 2.0 mm. The 0-80 screws were threaded into the plate so that W O 97/13981 PCT~US9611S932 approximately 6 threads showed on the non-head side (i.e., threaded posts about 2.2 mm in height projected from the flat plate).
A silicone rubber mold was prepared from this master and a polyethylene fastener element was produced from the mold according to the procedure describedin Example 1. The resulting fastener element was a polyethylene film having a square array of 2.2 mm high threaded posts projecting from one major face of thefilm (see Figure 17). The threads extended about 0.2 mm out from the sides oftheposts. When the faces cont~ining the threaded posts of two such polyethylene fastener element were pressed together, the fastener elements formed a self-mating lo fastener.

Example 7 A fastener element having a square array of microstructured posts on one major face was made in a manner substantially identical to that described in Example 1, except that a different master was used to form the rubber mold. The master was made by rn~c.hinin~ the master used in Example 6 such that each screw60 had four flat faces 63 uniformly disposed around the circumference of the screw (see Figure 10). The flat faces were separated by portions ofthe screw sidewalls 61 which still retained the threads 62.
A silicone rubber mold was prepared from this master and a polyethylene fastener element produced from the mold according to the procedure described in Example 1. The resulting fastener element was a polyethylene film having a square array of 2.2 mm high threaded posts projecting from one major face of the film (see Figures 11 and 18). The posts had six ridges protruding about 0.2 mm on the postsidewalls 72 directed at the center of the mating cavity (see Figure 1 1). The mating cavity is defined by four ~dj~c~nt posts 70 in the square array. When two such polyethylene fastener elements were pressed together, the fastener elements formed a self-mating fastener. The projecting posts on the two fastener elements were disposed so that the threads projecting from sidewalls of the corner of the posts were interlockingly engaged (see Fig. 11).

W O 97/13981 PCTrUS96/lS93Z
Example 8 A fastener element prepared according to the procedure described in Example 6 was treated with a primer and coated with an adhesive on the flat side of the polyethylene film (the side opposite the mating elçmentc). The flat side of the 5 f~ctçntor element was primed with a acrylic based polyolefin primer (available as product number 4298 from 3M, St. Paul, MN) using a small brush. Af'ter the primer was allowed to air dry for 20 minlltes, a 0.25 mm acrylic pressure sensitive transfer adhesive carried on a removable liner (F9473PC, available from 3M, St.
Paul, MN) was l~min~ted onto the primed side of the fastener element with a 2.4 kg 10 hard, rubber roll. After removal of the liner, the fastener element was adhesively l~min~ted to an ~IIlminl-m plate. The adhesive backing thus allowed attachment of the self-mating fastener element to a substrate.

Example 9 Another fastener element of the present invention was prepared by the following procedure.
One end of a piece of 3MO Optical T ighting Film #2300 Acrylic (available from 3M, St. Paul, MN), approximately 90 cm X 10 cm, was secured, grooved face down, to a bench top with m~ ing tape. The 3MO Optical Lighting Film includes 20 a plurality of subst~nti~lly 90~ included angle ridges. The depressions in the surface of the film are about 0.18 mm in depth. The unsecured end of the film was grasped in a manner such that a tear could be initi~ted in a grove approximately 2 cm from the edge of the film and the film torn along its length. The film was torn at an angle of between approximately 15-30~ from the horizontal to produce a clean, straight25 edge having a subst~nti~lly constant acute angle along one piece of the film and a complementary obtuse angle on the edge of the corresponding piece of film. The strips produced in this manner were cut into apploxi-,-dlely 6.5 cm lengths (herein after referred to as "master elements") and used to assemble a f~ctener master 112, a portion of the cross-section of which is illustrated in Fig. 14, in the following 30 manner:

CA 02234l00 l998-04-06 W O 97/13981 PCT~US96/15932 The grooved faces 105, 106 oftwo master elen~ents (~, B) were nested together so that the acute tear angle edge 100 of one element (B in Fig. 14) extended beyond the obtuse tear angle edge 101 ofthe second element (A in Fig.
14) by four ridges. The smooth face 102 of a third master element (C in Fig. 14)5 was then placed against the smooth face 103 ofthe second master element (B) with the acute tear angle edges 100, 104 aligned. The grooved face 108 of a fourth master element (D in Fig. 14) was then nested with the grooved face 107 ofthe third master element (C) with the obtuse angle tear edge 109 being indexed four groves below the acute tear angle edge 104 ofthe third element (C) and aligned 10 with the obtuse tear angle edge 101 of the first master element (A). The st~c~ing pattern (AB CD ABCD.. ) was repeated until a fastener master 112, approximately 1.2 cm X 6.5 cm was assembled. The total assembly was clamped together using a number of binder clips (5/8 inch capacity binder clip No. 100500 distributed by IDL
Corp., Carlstadt, NJ).
lS A master mold of the fastener master was prepared according to the following steps:
a) Forcing a vinyl siloxane dental impression material (3M
ExpressO, available from 3M, St. Paul, MN) into the contoured edge ofthe fastener master with the m~nllf~ctllre's supplied application device, being careful to avoid e-~LI~h~ing air bubbles between the impression material and the fastener master;
b) Cont~ining a pool of the dental impression material on a glass plate between two ~lllmin~lm spacer bars (approximately 0.32 cm X
1.25 cm X 2 cm) positioned approximately 2.5 cm apart;
c) Centering the fastener master over the spacer bars such that each end of the fastener master overlapped each spacer bar approximately 0.5 cm and forcing the h,lpl~;;ssion filled face ofthe fastener master into the pool of impression material until the hllpl ~s~ion filled edge of the fastener master contacted the spacer bars;

CA 02234l00 l998-04-06 W O 97/13981 PCTrUS96/15932 d) Positioning two additional ahlminllm bars (approximately 0.6 cm X 0.6 cm X 10 cm) in the h~p~ssion material pool such that they contacted the ends of the spacer bars, thereby forming a co..~ .erlt well for the i",pl es~ion material;
e) Allowing the i",plession material to cure;
f) Removing the fastener master from the cured h"pl ession material and trimming the ends of the cured mold to provide an apploxim~lely 2.5 cm long mold ofthe master; and g) Securing end dams to the thus trimmed mold to provide a lo well for subsequent fastener element molding.
Fastener elements were prepared by filing the master mold with a vinyl plastisol (#D1902-50 Black, available from Plast-O-Meric, Inc. Wallkçch~, WI) and curing the plastisol in a circ~ tin~ air oven at 204~C (400~F) for 15 min~tes. The cured plastisol was demolded to produce a flexible, compliant fastener element (50 15 durometer) having a plurality of grooved ridges which were replicas of the grooved ridges 110 of master 112 (and inverted replicas of the depressions in the mastermold). Two such fastener elements were engaged with light finger pressure and ~ could be readily c~ ng~ged by pealing one fastener element from the other. Figures 15 and 16 show a cross-section of the fastener elements just prior to engagement20 and in interlocking engagement, respectively. The fastener had a good holdingforce without being fully engaged. Much like a zipper, only a small force was needed to close the fastener if the closure process was begun at one end of the fastener and progressed to the other end. A large force was required to open thef~ctçnPr if applied along its entire length.
2s Example 10 A related set of fastener elements were prepared using the master mold of Example 9, subst~nti~lly following the procedure of Example 9, except that a firmer vinyl plastisol (#D1902-78 White, available from Plast-O-Meric, Inc.) was used to 30 form the fastener elements (78 durometer). The fastener elements were readily engaged and rli~en~ged, with those described in Example 9.

W O 97/13981 PCTrUS96/15932 All publications and patent applications in this specification are indicative ofthe level of ordinary skill in the art to which this invention pertains.
The invention has been described with reference to various specific and s prere-,ed embodiments and techniques. However, it should be understood that many variations and modifications may be made while remaining within the spirit and scope of the invention.

Claims (14)

1) A first fastener element adapted to be mated in an interlocking arrangement with a second fastener element, the first fastener element comprising:
a polymeric substrate comprising a plurality of first mating elements projectingtherefrom, the first mating elements each comprising a first mating surface which is adapted to engage a second mating surface on a second mating element projecting from the second fastener element, wherein a cross-section of each first mating element through the first mating surface comprises a plurality of microprotrusions extending therefrom, the microprotrusions having a height of no more than about 400 microns and a width of no more than about 400 microns;
the first fastener element is capable of being engaged with the second fastener element such that the engaged fastener elements are separable by a disengagement force related to the number of interlockingly engaged microprotrusions; and the polymeric substrate, the first mating elements and the microprotrusions are formed from one polymeric material.

2) The fastener element of claim 1 wherein first mating elements comprise solid mating elements.

3) The fastener element of claim 1 comprising first mating elements having an outer surface and a hollow core, wherein a portion of the outer surface comprises the microprotrusions.

4) The fastener element of claim 1 wherein the first mating elements comprise a plurality of discontinuous mating elements.

5) The fastener element of claim 1 comprising the first mating elements on a first major face and further comprising an attachment component on a second major face.

6) The fastener element of claim 1 wherein the first mating elements comprise ridge-like mating elements and the microprotrusions comprise microscopic ridges projecting from the ridge-like mating elements.

7) The fastener element of claim 1 wherein the first mating elements comprise post and the microprotrusions comprise microscopic ridges projecting from the posts.

8) The fastener element of claim 1 wherein the first mating surface has a draft of no more than about 30°.

9) An article comprising the fastener element of claim 1.

10) A first fastener element adapted to be mated in an interlocking arrangement to a second fastener element, the first fastener element comprising:
a polymeric substrate comprising a plurality of mating cavities, the mating cavities comprising a first mating surface which is adapted to engage a second mating surface on a second mating element projecting from the second fastener element, wherein a cross-section perpendicular to the first mating surface comprises a plurality of microprotrusions extending therefrom, the microprotrusions having a height of no more than about 400 microns and a width of no more than about 400 microns;
the first fastener element is capable of being engaged to the second fastener element such that the engaged fastener elements are separable by a disengagement force related to the number of interlockingly engaged microprotrusions; and the polymeric substrate, the first mating elements and the microprotrusions are formed from one polymeric material.

11) A fastener comprising:
first and second fastener elements;
the first fastener element comprising a first polymeric substrate having a plurality of first mating elements projecting therefrom, the first mating elements comprising a first mating surface, wherein a cross-section of the first mating elements through the first mating surface comprises a plurality of first microprotrusions extending therefrom:
the second fastener element comprising a second polymeric substrate having a plurality of second mating elements projecting therefrom, the second mating elements comprising a second mating surface, wherein a cross-section of the second mating elements through the second mating surface comprises a plurality of second microprotrusions extending therefrom;
wherein the first and second fastener elements are adapted to be engaged such that at least one of the second mating elements is retained in a mating cavity defined by adjacent first mating elements through an interlocking interaction of the first and second mating surfaces;
wherein the first and second microprotrusions have a height of no more than about 400 microns and a width of no more than about 400 microns;
the first and second fastener elements are capable of engaged such that the engaged fastener elements are separable by a disengagement force related to the number of interlockingly engaged microprotrusions;
the first polymeric substrate, the first mating elements and the first microprotrusions are formed from one polymeric material; and the second polymeric substrate, the second mating elements and the second microprotrusions are formed from one polymeric material.

12) The fastener of claim 11 wherein the polymeric substrate comprises a plurality of first mating elements projecting therefrom, the mating cavities being defined by adjacent first mating elements.

13) The fastener of claim 11 wherein the first polymeric substrate, the first mating elements and the first microprotrusions are formed from a first polymeric material; and the second polymeric substrate, the second mating elements and the second microprotrusions are formed from a second polymeric material.

14) A method of fastening articles comprising:
(a) providing a first fastener elements and a second fastener element;
the first fastener element comprising a first polymeric substrate having a plurality of first mating elements projecting therefrom, the mating elements having a first mating surface, wherein a cross-section perpendicular to the first mating surface comprises a plurality of first microprotrusions extending from the first mating surface;
the second fastener element comprising a second polymeric substrate having a plurality of second mating elements projecting therefrom, the second mating elements having a second mating surface, wherein a cross-section perpendicular to the second mating surface comprises a plurality of second microprotrusions extending therefrom, and (b) engaging the first and second fastener elements, wherein at least one first mating element is retained by an interlocking interaction of the first and second mating surfaces in a mating cavity defined by adjacent second mating elements;
wherein the first and second microprotrusions have a height of no more than about 400 microns and a width of no more than about 400 microns;

the first and second fastener elements are capable of being engaged such that the engaged fastener elements are separable by a disengagement force related to the number of interlockingly engaged microprotrusions;
the first polymeric substrate, the first mating elements and the first microprotrusions are formed from one polymeric material; and the second polymeric substrate, the second mating elements and the second microprotrusions are formed from one polymeric material.