CA2133405A1

CA2133405A1 - A method of attaching articles and a pair of articles fastened by the method

Info

Publication number: CA2133405A1
Application number: CA002133405A
Authority: CA
Inventors: Forrest J. Rouser; Robert Lee Erwin
Original assignee: Individual
Current assignee: 3M Co
Priority date: 1992-04-28
Filing date: 1993-04-21
Publication date: 1993-11-11
Also published as: DE69303169D1; EP0638146A1; JP3558087B2; KR950701415A; BR9306299A; US5201101A; DE69303169T2; JPH07506416A; EP0638146B1; ES2088675T3; WO1993022566A1

Abstract

A plurality (e.g. a pair) of misaligned, fastened articles (10, 12) with structured surfaces is disclosed. The structured surfaces have elements (15, 25) which may bend and twist during attachment resulting in a higher peel strength than when the articles are aligned. A method of attaching a pair of articles (10, 12) is also disclosed.

Description

r'~~VO 93/22566 2 1 3 3 4 0 5 P~r/~593/03791 . :

A M~E ~ O D O F AlrrAC~N G A~RlICI~ES AiNnD A P~ OF
A3RIICIJES FASl~EN~ BY 1~33E M~Ell~O D

5 ~he prese~tin~en~on rela~ to fas~ned aricles, and a me~od ofa~aching ar~cles havLng a s~ucbu~ed su~face on one side.

~emY~
~he a~ is reple~ with fas~ners for a~ching ar~cles together.
For ex2unple, U.S. Pa~nt Nos. 2,717,437 and 3,009,235 to Mesba ~ach aricles having loops and hooks. VYhen the ar~cles ale broughtinto c~n~ct ~th each other,the hooksin~rlock with theloops. U.S. Pa~nt Nos.
~,4999898 to ~nde ~ n, 3,192,589 to Pealson, 3,266,113 ~o Fbanag~J,Jr., 3,4089705 ~D ~ayser etal., and 4,520,943 to Nielson ~h a plu~ity of masro aspe~es or pro~u~ons, ~hatfunction as an a~a~hment means when brought in~D con ~ t ~n~h ~nn~arly shaped nnacro asperities unth cDrre~pondingly shaped ~o~æs. Addi~on2~ly, fasteners uti~zing a plu~ity of longitudina~y extending rib and groove elements which deform and mechanically interfere and re~liently interlock with each other have been disclosed in U.S. Patent Nos.
20 2,144,755 to Preedman, 2,558,367 to Madsen, 2,780,261 to Svec et al., 3,054,434 to Ausnit et al., 3,173,1~4 to Ausnit~ 3,198,228 to Naito and 3,633,642 to Siegel.
U.S. Pa~ent No. 4,875,259 to Appeldorn discloses several intermeshable articles. Some of the species of intermeshable articles disclosed 25 in 4,875,259 require alignment b,efqre pressing the structured surfaces together.

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Di~closure of theInvention The present invention is directed to a method of fastening articles -~toge~her and the resultant fastened ar~cles. The present invention provides -30 fastened ar~cles which (1) may be fastened together in a plurality of positions to afford ~ndom alignment o~ articles to be fastened, (2) include a surprisingly ,~ I
;~
. -wo 93/22s66 - ' - Pcr/US93/037 strong peel s~en~ at~achment; and (3) do not r~quire alignment prior to attachment.
According to the present invention, ~as~ned articles are provided comprising a first and second ar~cles each having at least one ma3or suffa~e at S least a por~on of ~hat sufface being a structured surface. The first and second ar~cles' structured s-urfaces include a plurality of tapered elements. Eaeh of the elements have dt least one side inclined relative to a Gommon plane at an angle sufficient to form a taper.
l3Oth the first and the s~ond articles' plurali~y of tapered 10 elements are sitllated to form a plurality of axes ineluding at least one first ar~cle and at least one second article longitudinal axis.
The first and second articles are fastened together with t~e first longitudinal axis situated at an angle relative to the se~nd longitudinal a~cis.Wllen the articles are fas2~ned together ~1) at least one of ~he tapered elements 15 of the first or the second ar~cle is axially bent or torsionally flexed rela~ve to its relaxed, unfastened ~sition, and ~2) the inclined sides of one of the first and second article's tapered ~ments are frictionally adhered to at leas~ some of theinclined sides of the other of the first and second article's tapered elements.
s Alternatively, the present invention may be described as a 20 method of fastcning a plurality of articles comprising the steps of: (1) providing a first article as d~cribed above, (2) si~a~ng the first ar~cle's plurality of tapered elements to fonn a plurality of axes including at least one first article longitudinal axis; ~3) providing a second article as described above, (4) situating - the second a~ticle's plurality of tapered elements to form a plurality of axes 25 including at least one second article longitudinal axis; (5) disposing the first longitudinal LXiS at an angle relative to the second longitudinal al~is; and (6)then pressing the structured surfaces of the first and the se~ond article together such that after the structured surfaces are pressed together, at least one of the tapered elements of the first or the second ar~cle is axially bent and torsionally 30 flexed relative to its relal~ed, unfastened position, and such that the inclined sides of one of the first and sec~nd article's tapered elements are fric~onally ~ Y~ 9~/22566 2 i 3 3 ~ 0 5 Pcr/us93/o37gl . 3 adhered to ~t least some of the inclined sides of the other of the first arld second ar~cle's tapered elements.

~~s~tiQn ~f the I2swin~
S The present invention will be further describ~d with reference to the accompanying drawing wherein li~e reference numerals refer to like parts in ~he several views, and wherein:
Figure 1 i a perspective ~iew of a first ar~cle in the form of an abrasi~ e sheet and a seeond article in the form of an abrasive holder fastened 10 according to the present invention;
Figure 2 is an enlarged perspective view of separated first and second articles with their longitudinal alces misaligned, and illustrating a plurality of taper~d members;
Figur~ 3 is an enlarged perspectiYe view of the first and second 15 articles of ~igure 2 after they have been pressed toge~her and fastened according to the present invention;
Pigure 4 is an enlarged cross-section of a ~ of fastened ar~cles similar ~ the ar~dcles shown in Figure 3;
Pigure 5 is a reduced side cross-section of the articles shown 20 partially in Pigure 4;
Figure 6 is a schema~c representation of the t;op of a flexible tapered element in an unfastened, relaxed state (solid lines) and a twisted, fastened state tdashed lines);
Figure 7 is a plan view of the first embotliment of frusto 25 pyranudal-shaped ~apered elements on the stmctured surface of one of the fastened ar~cles according to the present invention which illus~ates a square cross-section for the tapered members;
Figure 8 is a sectional view of the st~uctured surface of Figure 7, s with parts broken away to illustra~e details of the geometry of the structured - 30 surface;
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2I33~0a Wo 93/22566 PCI/US93/037 Figure 9 is an enlarged sectional view of the abrasive sheet ofFigure 1 illus~rating a structured surface on one side and an ab~asive on the other side;
Figure 10 is a pl~ view of a second embodiment of one of the S fastened ar~cles according to the present invention, illustra~g a regular he%agonal cross-sec~on for the tapered members;
Figure 11 is a plan view of a ~ird embodiment of one of the fastened ar~cles according to the present invention, illustrating a triangular cross-sec,~on for the tape~ed members;
Figure 12 is a graphi,~ representa,tion of the results of a peel strength test performed on a pair of f,astened articles acoording to the first embodiment of ~ e present inven,~on;
F;gure 13 is a sehematic perspective ~/i,, w illus,~a~ng how the peel s~¢ength test of Pi,gure 12 was perform~d;
Figures 14A through 14E ,are represen~ations of the alignments of c ~e pair of f,astened ,~cles during the peel s~eng~ test summ,~ in Figure ,. 12;
, Figure 15 is a photomicrograph ,taken ,through a L~itz .. ~
Microsoope at a magnification of forty tim,es (40X) illustrating a~i,al bent ,an,d 20 torsional twisted pyramidal-shaped members of first ,and ,second f,astene,d ,~cles a,ccording to the present inven~ion;
`, Figure 16 is a phot~micrograph t,aken through a L~
Micro~,pe at a magnification of eighty times (80X) illustrating a~cial bent and ~; torsional t~visted pyramidal-shaped members of first and second fastened articles 25 according to ~e present invention; and Figure 17 is a schematic illustration showing the equipment used to take the photomicrographs of Figures 15 and 16.

- Detail~Descrinti~n , 30 Refer~ing now to Figures 2 and 3 of the drawing, there is shown "~
a first embodiment of fastened~rticles generally designated by the reference character 10. The articles 10 include a first article 12 having a major surface ~ ,!

' 2l33~15i: il 0 93/22566 Pcr/usg3/o379l which includes a structured surface 14. The structured surface 14 includes a plu~lity of ~apered e~ements lS. Each element lS has at least one side 16 inclined relative to a common pl~ne C at an angle sufficient to fonn a taper.
The ta~ered elements 15 are situated to forrn a plurali~ of irnagina~ a~es S ineluding a first ar~cle longitudinal a~is L.
The fastened ar~cles 10 also include a s~ond article 20 having a major sur~ace which indudes a structured surface 24. The structured sufface 24 includes a plurali~r of tapered elements 25. The tapered elements 25 each have at least one side 26 inclined relative to common plane C' at an angle 10 sufficient to form a t~per. The ~apered elements 25 are situated to form a plurality of imaginary axes including a second article longitu~inal alcis L'. The tapered elements 15 and 25 may, for example, have a shape in an unfastened posi~on such as that shown in Pigure 2.
Preferably the axes L and L' are situated generally between 15 periodie arrays or rows of tapered elements (e.g. 15 or 25) such that ~he rows are symme~cal about ~e a~es L or L' (see eOg. Fi~ures 2 and 3). However, alt~rna~vely, the Lses may be situated between periodic rows of tapered elemen~s that are not symmetrical about the axes~(see e.g. axis A and Figure 10). I~ should be noted that it is within the scope of the invention ~at the 20 tapered elernents need not be penodic and may even be arranged randomly. In a case whe~e the tapered elements do not form a periodic arIangement (e.g.
where ~hey are randomly arranged), an imaginary axis may be ar'oitT~ily established.
The first 12 and second 20 articles are fastened together by a 25 method according to the present invention including the steps of: (1) providing the firs~ article 12; (2) providing the second article 20; (3) disposing the first longitudinal axis L at an angle (theta ~) relative to the second longitudinal axis L' (Figure 2); and (4) then pressing the structured surfaces 14 and 24 of the first 12 and the second 20 article together (Figure 3). Afte-r the structured 30 surfaces 14 and 24 are pressed together, (1~ at least one of the tapered elements 15 or 25 of ~e first 12 ~r the second 20 article is axially bent and torsionallyflexed relative to its relased, unfastened position (e.g. as shown in Figure 2),1`, .

wo 93/22~66 Pcr~VS~3/037 and (2) ~he inclined sides 16 of the first article's ~ered elements 15 are fric~onally adhered to the inelined sides 26 of the second article's tapered elements 25.
As used in this applica~on, the phrase Yaxially bent" is defined 5 as follows: The tapered elemen~s 15 and 25 have a rela~ed sha~e in an unfastened position such as that shown in Figure 2. There are no external ~orces acting on the tapered elements 15 or 25 in the unfastened position. In the unfastened posi~on, the tapered elements (e.g. 15 and 25) h~ve an imaginary longitudinal axis T (Figure 5) which passes through the geometric 10 center or centroid of the tapered element (e.g. 15 or 25). For example, in Figure 5, b~cause of the symme~ical shape of the tapered elements and the assump~on that the tapered elements have a constant density, the longitudinal asis T is pe2~endicular to the common plane C or C'. In this application when it is said that the tapered elements are "axially bent", it is meant that the 15 elements are deflect-ed or de~ormed to a shape having an imagina~y longitudinal a~cis T' ~:Figure 5) passing through ~e geometric center of the defonned element which is a~ an angle or otherurise displaced rela~ve to the relaxed posi~n of the imag~ longitudinal aicis T in the unfastened state.
As used in ~is application, torsionally flexed or twisted is 20 defined as follows: The tapered elements 15 or 25 have a rela~ed orientation in planes perpendicular tQ the imaginary longitudinal axis T (see Figure 2) in an - unfastened state. In ~is applica~on, when it is said that the tapered elements are torsionally twisted, it is meant that ~e elements are radially displaced relative to their orientation in the unfas~ened state or posi~on using the axis T
25 and a corner of surf~ce 11 as refe,rences. ~.
Referring now to Figures 5 and 6 there is shown an e~ample of the first embodiment of articles shown in ~igures 2 and 3 wherein the first .. article 12 is cons~ucted from a relatively flexible material so that the tapered i elements 15 may bend and the second article 20 is constructed from a relatively : 30 rigid material so that the elements 25 do not bend. As best seen in Figure 5, the shape of the second a~cle's tapered elements 2~ remains generally the ,, ,"

' i`VO93/22566 2133~Q5 PCI`/US93/03791 sarne in the fastened and in the unfastened position. However, the first ar~cle's ~a~ed elements 15 both a~ially bend and twist.
Refer~ing to the tapered elements 15 in Figure 5, the elements 15 are deflected or deform~d to a shape having an imaginary longihldinal axis T' S passing through the geome~ic center of the deformed element 15 which is at an angle r~lative to the relaxed position of the imaginary longitudinal axis T (notshown for the element lS in Figure 5~ in the unfastened position. Compare the positions of the imaginary axes T and T' in Figure 5.
The elements 15 shown in Figures S and 6 also torsionally twist.
10 As best seen schematically in Figure 6, element 15 has an orientation in planes pe~pendicular ~o the imaginary longitudinal a~ds T in an Imfastened state (solidlines), such as the plane which pas~es through the top surface l l . In the fastenod position, the tapered element 15 is torsionally displaced or "twisted"
(dashed lines). The element lS is radially or torsionally displaced the angle hu15 relative to its orientation in the unfastened state or posi~ion using the axis T and a corner of surface 11 as references.
It should be noted that the angle tau does not necessarily corre~ond to the angle theta for the fastened art~cles. Instead, the angle tau may vary widely for different tapered elements 15 or 25 on the same article 12 - 20 or 20. If one of the ar~cles 12 or 20 is constructed from a relatively ngid m~terial and the other article is constructed from a flexible material (see Figure 5), the angle tau for the rigid matenal is gene2~1ly zero. Alternatively each ofthe articles 12 or 20 may be constructed from a flexible ma~erial.
Figures 15 and 16 are photomicrographs of first 12 and second . 25 20 flexible f~tened artic~es which, illustrate flexible tapered elements 15 and 25 that are both aldally bent and torsionally twisted or fle~ed.
Pigure 17 illustrates the equipment used to take the photomicrographs of Figures 15 and 16. Clear or transparent first and second ar~cles 12 and 20 were provided such as described in Example 1 infra. The 30 structures were attached to one another by the following steps: (1) The a~is L
& L' are misaligned. (2) The ar~cles 12 and 20 are pressed together with modera~e finger pressure. (3) The articles 12 and 20 are then placed on the !

.~ ~

Wo 93/22566 ~ 1 3 3 4 05 - 8 - Pcr/usg3/037 ~ay of a Leit~ Optical Microsc~e 100 (e.g. th~ Leit~ Optical Microscope, generally available ~om L~ of Wetzlar, Germany or Technical Instruments Co. of San Franeisco, Califo~).
An X Y theta stage Boeckeler Digital micrometer (reference S charaeter 101) mo~el 1398 gene~lly available from TKL Inc., of Newport Beach, California was provided so that a user could ~pulate the position of the articles 12 and 20 rela~ve to the microscope 100. A lOX objec~ve 102 and a lOX eye~i~e 104 generally available from L~itz of Wetzlar9 Germany or Technical I~s~uments Co. of San Prancisco, Califomia (e.g. mo~el no.
10 NP~lOX) were us~d to take the photomicrographs shown in Figulres 15 and 16.

The microscope 100 was f~used through the back of anicle 12 to the base of element 15 and ~e dp of element 25. The sample was illuminated from the bottom as shown in Pigure 17, by means of an Intralux 15 5000 120 vol~, 180 watt light supply 106, generally available ~rom the Volpi Manu~acturing Company, Inc. of Auburn New York. Light passed through ar~icle 20 then 12 to ~e objective 102o A camera 109 is provided. For example, the camera may be a WILD eamera 109 generally available from WILD of Heerbrugg, Sw~t~erland.
20 The camera 109 is loaded with film such as Polaroid high speed black and white 667 film. An exposure device 110 is provided such as a Wild photomat MSP 45 generally available ~rom WILD of Heerbrugg, Switærland.
The camera 109 has a 0.8X magnification ~or a photomicrograph magnification of 80X (e.g. the photomicrograph of Figure 16). The Wild 25 pho~oautomat ~PS 45 (reference çharacter 110) con~olled the exposure of the camera 10~. For Figure 15, a SX objective was substituted.
Referring now to Figures 2 and 3, the angle theta ~ is the angle between the axes I, and L'. The angle theta ~ is generally between more than - - zero (O) and less than about t venty (20) degrees and is preferably seven-and-30 one-half (7.5) degrees for reasons set forth below.
When the first 1~ and second 20 ar~cles are brought together ;
they adhere to one another, since the inclined sides 16 of the first ar~cle's 0 93~22566 Pcr/Vsg3/o379l , .,~ g tapered elements 15 fric~snally adhere to the inGlined sides 26 of the second arffcle's tapered elements 25. Because ~he ar~cles 12 and 20 may be attached to one another without hrst aligning the ar~cles, a user may sandomly align the articles and then press them together. The multipositionable feature of articlesS 12 and 20 is a convenient characteristic for a user.
The s~uctured sur~aces 14 and 24 of the first 12 and second 20 articles generally comprise solid py~midal-shaped elements ha~g a polygonal-shaped cross-sec~on. The phrase py~dal-shaped elements is used herein t~
include truncated versions such as the frusto pyramidal-shaped elements lS and - 10 25 shown in Figures 2 and 3. The pyramidal-shaped elements 15 and 25 generally include a polygonal-shaped cross-see~on such as the square shown in Figures 2 and 3. Alternatively, the cross-sec~on may be ~ectangul~r, negular hexagonal, hexagonal, triangular, cir~ular, elliptical, combinations thereof, orcombina~ons of s~aight and arcuate line segments.
The par~cular material used to construct the ar~cles 12 and 20 may be any suitable material so long as at least one of the matenals affords a fle~ciUe tapered element 15 or 25 ~at may alcially bend and torsionally ~wist orflex. Various materials may be used such as but not limited to commercially available acrylics, vinyls, polymers (including electron beam or ~adiation cured20 polyme~s~, polyethylenes and polycarbonates. Particular exaIslples inchlde polymethyl methacrylate, polystyrene, non-rigid polyvinyl chloride with plasticizers, and biaxially-oriented polyethylene terephthalate. Additionally, the material may be biodegradable, transparent or translucent, elec~ically conductive or magne~c a~cording to the particular application. Addîtionally, 25 any of the materials mendoned in U.S. Patent No. 4,875,259 may be used.
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'''J Example l An example of one of the articles 12 used to provide the first embodiment of fastened articles 10 is shown in Figures 7 and 8. The tapered 30 elements 15 include top surfaces or por~ons 11 which define a height H
measured from the common plane C.

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WO 93/~2566 2 1 3 3 4 S lo - PCI`/~JS93/037!~ 1 The articles in this example compnse identical, r~ctangular s~ips of PVC film wi~h plastic~ers. Each of the ar~cles 12 and 20 wae flexible and had integ~l, uniform flexible elements lS and 25. The dimensions of the articles were: approximately 12.7 cen~meters, (5 inches") long, about 2.54 5 centimeters. (1 inch") wide, and with total thichlcss of about 1.~1~27 millimeters. (4~50 mils).
The articles 12 and 20 comprised polyvinyl chlo~ide construct~l from clear ~516 PVC pellets obtained from Alpha Chesnical and Plas~cs Corporation 9635 Indus~ial Drive, Pineville, North Carolina (manufacturer no.
2215-80). The articles 12 and 20 had a first broad smooth surface, and a second broad s~uctured surface (e.g 14 and 24) wherein the structure was of the orthogonal type having two mulually perpendicular axes of penodicity, and one longitudinal axis L or L' (as shown in Figures 2, 3 and 7).
The structured surfaces 14 and 24 had about a 0.63 millimeter or 25 mil groove depth or height H, a 9 degree 36 minute (rounded to 10) included angle between tapered surfaces 16 or 26 (shown as the angle phi in Pigure 8), a pitch or lat~ce constant of about 0.33 millimeters, (13.08 mils) ~shown as P in Figure 7~, top dimensions of approximately 0.12 by 0.12 mm.
(4.86 by 4.86 mils) (e.g. the length of the sides of the top surfaces 11 or 21),and a width at the base of grooves of about 0.23 millimeters, (9.06 mils) ~shown in Pigure 7 as the Diameter D). The distance G shown in Figure 8 is simply P - D or 0.10 millimeters.
When polyvinyl chloride made from clear #516 PVC pellets obtained from Alpha Chemical and Plastics Corporation 9635 Industrial Drive, - 25 Pineville, North Carolina (manufacturer no. 2215^80) was used, it was found that ~e flexible elements with the above mentioned dimensions twisted and bent sufficiently to enable the articles 12 and 20 to be fastened in a plurality of angular orientations.
Numerous factors affect the ability of the tapered elements 15 or 25 to bend ur twist when the articles 12 and 20 are pressed together. For example, the material characteristics, the cross se~tional shape of the elements; 15 or 25 (e.g. square or rectangular etc.), the angle between tapered surfaces , .

2~3~05 ~vo 93/22566 PC~r/uss3/

(e.g. the angle phi), ~he height H to diameter D ratio H/D and the pitch P to diametPr D ratio P/D a~e all believed to affe~t the ability of the tapered elements to bend and twist.
All other factors held constant, the height H to diameter D ratio S should be sufficient to afford bending and lwisting of the elements 15 or 25. In example 1, the height to diameter ratio H/D was (0.63 millimetersl 0.23 millimeters) = 2.74. This H/D ~atio for this matenal was found to worlc well and to provide for attachment at different angular orientations. All other factors held constant, the H/D ratio should be numerically large enough to 10 afford flexing and twisting of the element 15 or 25. However, if the ratio H/I:
is too large, then the tapered elements 15 and 25 bend excessively and tend to interfere with each other, thereby impeding attachment of the articles 10. If the ratio H/D is too small, then the tapered elements 15 or 25 tend to become too Iigid to twist and bend and thus "bending'' at~achment of the arffcles 12 and 2015 is deleteriously affected for ~hat material.
c Additionally, all other factors held constant, the pitch P to diameter D rado P/D should be sufficient to afford bending and twis~ng of the elements 15 or 25. For ex.ample, in example 1, the PID ratio is 0.33l0.23 =
1.43. This P/D ratio for this example was found to work well and to provide 20 for attachment at different angular orientations. All other factors held constant, the PID ratio should be numerically large enough to afford flexing and twisting ~, of the element 15 or 25. However, if the ratio PID is too large, then it is j believed that the elements 15 and 25 will not twist and bend and will instead remain in or retu~n to their unfastened position. If the ratio PID is too small,, 25 then the tapered elements 15 or 25 tend to become too closely spaced and tend to e~cessively interfere with each other so tnat little or no bending or twisting occurs.
The articles 12 and 20 described in Example 1 were constructed in the following manner. First, a Pasadena Hydraulics, Inc., 50 Ton Model 30 Compression Molding Press ~generally available from Pasadena Hydraulics, Inc. of Pasadena, California) was used. The molding surfaces were constructed ' ,,1 21:~WO 93/22~66 ; Pcr/lJS93/037 to provide an arti le having the dimensions set forth above in Example 1. The PVC material described above was used.
- The molding surfaces were constructed by hrst diasnond cutting a UV curable polymer to provide a m~lding sample ar~icle hav~ng the dimensions 5 and shape set forth above in ~nple 1. Optionally, any suitable acrylic plas~c material may ~e used. Diamond turning equipment such as the Moore Special Tool Co. Model M~0 or the Pneumo Co. Model SS-156 (e.g. SN 76936) may be used to construct the molding sample article.
Of course, it will be appreciated by those skilled in the art that 10 the fastened ar~cles of the present invention are not necessarily individually m~chined but are instead produced by a replication process. Thus, to construct the molding surfaces, the molding sample mentioned above was used in a conventional electroforming process (similar to the electroforming process mentioned in U.S. Patent No. 4,871,623~ to provide the suitable molding 15 surface. For example, a nickel molding surface may be electroformed f~om the acrylic plastic sample article mentioned above.
Optionally, in some structured surface designs, such as illustrated - in Figure 11, it may be advantageous to directly machine a molding surface - from a metal, molding surface ma~erial, wi~h no electroforrning process.
. 20 Another op~on may be to initially machine a surface similar to the desired - molding surface in a metal material, then molding a molding sample article f~om the metal surface, and then electrofonning the molding surface using the molding sample article.
Once the molding surfaces were const~ucted, the PVC pellets 25 were then initially placed between the two molding surfaces of the Compression Molding Press. l he molding surfaces of the press were heated to 350 degrees . fahrenheit, after which a force of about 4350 pounds per square inch was exerted on the molding surfaces for a time period of two minutes. After two minutes, the force was increased ~o 45,000 pounds per square inch for a time 30 peri~d of two minu~es.
The molding surfaces were then cooled to 100 degrees fahrenheit while a force of 45,000 pounds per square inch was maintained for a ~me /i ", 21!O ~3/22S66 P(~US~3/03791 - ~3-~iod of ten minutes. After the ten minute ~me period, the 45,0~ pounds per square inch force was removed. The PVC ar~cle was then removed from the molding surfaces.
There are several other methods which may be used to produce S the articles 12 and 20 according to the present invention which are hlown in the art, such as the methods disclosed in U.S. Patent Nos. 3,689,346 and 4,244,683 to Rowland, 4,875,259 to Appeldorn; 4,576,850 to Mertens; and U.K. Patent Application No. GB 2,127,344 A to Pricone et al.
As s~ated above, the cross-section of the t~pered elements need 10 not be s~uare. The cross-section of the tapered elements may eomprise any polygonal shape including combinations of arcuate or st~aight lines, including but not limited to hexagons, triangles, ellipses and circles.
Figure 10 illust~ates a second alt rnative embodiment of one of the fastened articles according to the present invention generally designated by15 the reference character 30 which has many parts that are essentially the same as the parts of the ar~cles 12 and 20.
Like the articles 12 and 20, ~e article 30 includes a s~uctured surface 34 having a plurality of tapered elements 35. Each element 35 has sides 36 inclined relative to a common plane X at an angle sufficient to form a 20 taper. The ta~ered elements 35 are situated to fol~n a plurality of axes . including a first article longitudinal a~cis A. Unlike the tapered elements 15 and 25, the cross-section of the tapered elements 35 are regular hexagons, and the tapered elements 35 are not arranged such that they are symmetrical about the '.
axis A.
Figure 11 illustrates a third a~ lternative embodiment of one of the fastened articles according to the present invention generally designated by thereference character 40 which has many parts that are essentially the same as theparts of the articles 30.
- Like the ar~cle 30, the article 40 includes a structured surface 44 having a plurality of t~pered elements 45. Each element 45 has sides 46 .i inclined relative to a common plane P' at an angle sufficient to form a taper.
The tapered elements 45 are situated to form a plurality of axes including a first .
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wO 93/22566 2 1 3 3 40 5 Pcr/US93/037~ 1~

article longitudinal ~s A'. Unlike the tapered elements 35, the cross~ on of the tapered elements 45 are triangles.
It should be noted that the tapered elements 15, 25, 35 or 45 of one article may be positive elements ~e.g. solid elements which project from S their re~eetive common plane C) and the elements of the other article may be negative elements (e.g. cavities which are re~ ~rom their respec~ive common plane C) so that the sides of the positive elements may engage with the sides of the negative elements to adhere there~o. Additionally, it should be - appreciated that the cross-sectional shape of the tapered elements of the first 10 article may be dissimilar to the cross-sectional shape of the tapered elements of the second article. For example, the hexagonal shaped tapered elements shown in Figure 10 may be positive elements and may engage with appropriately a~anged negative, triangular shaped elements (see Figure 11~.

~lication and Use Pigures 1 and 9 illustrate one of many appllcations for the present invention. The first ar~cle 12 may comprise a sheet of polymeric material or film 2 having first 1 and second 3 mayor side surfaces with the structured surfaces 14 situa~ed on the first major side surface 1 snd with an 20 abrasive 7 situated on the second major side surface 3. The polymeric material having the abrasive 7 may comprise a polyvinyl choloride sheet (with the structured surface) laminated to the backside of a coated abrasive discussing an- extrusion process (e.g. grade 600 Wetordryn' Tri-M-Ite A weight paper available from Minnesota Mining and Manufacturing Company, (3M) of St.
25 Paul, Minnesota, U.S.A.~. Alternatively, the film 2 may be constructed by providing a polymeric film with a structured surface on one side and ~,vith abrasive particles embedded on the other side. Figure ~ illus~ates a manually held abrasive holder 9 which may be used as the second article 20.
~. For e~ample, the abrasive holder 9 may comprise a monolithic body molded A~, 30 from a resilient, co-npressible ~oamed polymeric material generally available ,-, from the Minnesota Mining and Manufacturing Company of St. Paul, , Minnesota under the ~ademark "Stikit". The structured surface 14 for the ,, ~,i , .,:: .. : ,.. . . .. . . ..

~O 93~22566 2 1 3 3 4 0 5 Pcr~US93tO3791 abrasive holder 9 may be integral with the stmcture of the abrasive ho~der 9 or,alternatively, the structured surface 24 may compAse a thin sheet or film havingfirst and second major side surfaces with the first major side surfa~ having a s~ucbured surface and with the second major side surface ha~ing a suitable S means for moun~ng the film, such as a coating of reposi~onable pressure sensi~ve adhesive for adhering the film to the abrasive holder 9.
As set forth below, it has been found that, surprisingly, the peel streng~h characteristics of the ar~cles 10 is greater at some angles (theta) that ar~ more than zero degrees than the peel strength characteristic of the articles10 10 at zero degrees. Thus, the side 8 (Figure 1) of the film 2 may form the angle theta with the longitudinal ~cis (e.g. L) of the structured surface on thefilm 2; and the side 6 of the holder 9 may be gene~lly parallel to the longitudinal axis (e.g. L') of struetured surface on the holder 9. Thus, when the film 2 is pressed onto the holder 9, the user need only align the side 8 of 15 the film 2 wi~ ~e side 6 of the holder 9 to afford a convenient and quick approximation of the optimal, preferred angle theta.

J
Test Results "
;? Referring now to Figures 12, 13 asld 14A through 14E, two ~ 20 articles 12 and 20 of the type described with reference to E~cample 1 were s tested for peel strength.
A senes of tests were run to determine the angular dependence of the peel force required to separate t~vo engaged, structured surface articles 10.
An Instron Model 1122 "Universal Testing Instrument", for precision testing 25 of the mechanical propertieslof mateAals was used in the tests. The , environmental test conditions were a constant temperature of 70 P. and constant relative humidity of 50 æ.
;3 Test samples wvere identical rectangular strips of PVC film with plasticizers. The dimensions of the film are described in exarnple 1. Each test ~; 30 strip had a first broad smooth surface, and a second broad s~ructured surface wherein the structure was of tl~ orthogonal type (the type shown in Figures 2 and 3) having two mutually perpendicular ases of periodicity, as described in ~l ~., ;., W093/22566 2~33~0S PCr/US93/037(~ l reladon to ~;;gu~es 2, 3, 7 and 8. The structured surface was the same as that described in e~cample 1~
Figure 13 schema~caUy illus~ates how ar~cles 12 and 20 were tested using the Instron described above. Ea~h of ~e ar8cles 12 and 20 had S flexible elements 15 and 25. Articles 10 were tested in pairs (e.g. 12 and 20).
Each sample pair was posi~oned with their second structured surfaces 14 and 24 in mutual contact and with their axes of penodici~ manually mis-aligned by the pr~detennined misalignment angle theta (0, 7.5, 15, 30 or 45, in respec~ve tests). The misalignment angles are ~hown in Figures 14A through 14E.
Each pair of misaligned sample strips was engaged in fricdonal - attachment by about a 20 Newton (4.5 lb.) force exerted by a smooth-rubber-surfaeed metal roller with 4.4 cm. (1.75 ~) tread-width, and a 4.76 cm. (1.875 ~) radius. In each test, the first smooth side (e.g. the side opposite 14) of a - "first" strip was fastened to a horizontal platen using a s~ip of tape coated on 15 both sides with a high-tack, pressure sensi~ve adhesive.
The horntal platen design permitted hanslational movement along a single axis in the horiwntal plane. One end of the "second" strip was attached to a ver8cally movable member of the t~est instrument with the plane ofthe attached portion perpendicular to the horizontal a~cis of movement of the 20 platen, and to the remaining fricdonally attached portions of the second strip (see Figure 13). As a result of the movable platen and during the course of each measurement, a gO angle was maintained at the separation interface between the ver~cally moving pordon of the second stnp and the fricdonally attached por~on of the first s~ip. The peel strength tested is h~own as 180 25 degree T-p ;~1. , ~ ' The instantaneous peel force, plotted as a function of vertical posidon, varied as the movable strip was moved in a vertical direcdon. The variadons were, at least in part, because the width of the separation interface varied due to the misalignment angle.
Both ~1) an instantaneous peak or maximum value, and (2) an av~age value over a time peri~d during which the separation interface was essendally constant, were measured in two separate runs for each misalignment .~
.j ~

2133~0~ ~~0 93/22566 ; ' ~ . Pcr/uss3/037 angle the~a. Both the instantaneous peak and average values were estimat~d after viewing the data provi,ding by the Instron and the testing equipment. Bothsets of pealc and ~time-average" values, shown in Table A, show that the maximum peel force is achieved at a misialignment aulgle of about 7.5. Results S of the tests are summa~iz~ in Table A, and the Kstatistical~ average values for the two runs are set forth in Table B. The data in Table B are graphically represented in ~:igure 12, with the average peel strength identified as the ~K"
curve and the peak peel strength identified as the "J" curve.

TABLE A

, Angle: Test Average Peel Peak Peel Num. Strength Stren~th Grams Fer inch Grams per inch . .
0 1. 100 135 2. 120 145 ii 7.5 1. 185 240 ~}
~t~ 20 2. 185 225 1. 180 200 2. 150 175 ~ ' .
", 25 30 ! " , . ' 2. 30 40 , .
~, 45 1. 40 48 2. 50 56 ,, 30 ',1 ", Table B is an average of the values shown in Table A.
,, _ ~s ., wo 93/22566 2 1 3 3 4 0 5 pcr/uss3/o3~ 1 TABLE B

Angle: Average Peel Ave. Peak Peel Strength Streng~
S Grams per inch Grams per inch 7-5 1~s 232.5 165 187.5 47.5 - - The present inven~don has now been desenbed with reference to seve~l embodiments thereof. It will be apparent to those skilled in tl e art that 20 many changes or addi~ons can be made in the embodiments described without depar~ing from the scope of the present inven~on. Thus, the scope of the present inven~on should not be limited to the structures described in this applica~on, but only by structures described by the language of the claims and the equivalents of those structures.

' .Y

Claims

What is claimed is:

1. Fastened articles comprising:
a first article having at least one major surface at least a portion of that surface being a structured surface;
said first article's structured surface including a plurality of tapered elements, each element having at least one side inclined relative to a common plane at an angle sufficient to form a taper;
said first article's plurality of tapered elements being situated to form a plurality of axes including at least one first article longitudinal axis;
a second article having at least one major surface at least a portion of that surface being a structured surface;
said second article's structured surface including a plurality of tapered elements, each element having at least one side inclined relative to a common plane at an angle sufficient to form a taper;
said second article's plurality of tapered elements being situated to form a plurality of axes including at least one second article longitudinal axis;
said first and second articles being fastened together with the first longitudinal axis situated at an angle relative to the second longitudinal axis such that at least one of said tapered elements of said first or said second article is axially bent or torsionally flexed relative to its relaxed, unfastened position, and said inclined sides of one of said first and second article's tapered elements being frictionally adhered to at least some of said inclined sides of the other of said first and second article's tapered elements.

2. Fastened articles according to claim 1 wherein:
in an unfastened position, said structured surfaces of said first and second articles comprise solid frusto-pyramidal-shaped elements having polygonal-shaped cross-sections.

3. Fastened articles according to claim 1 wherein in an unfastened position, said structured surface of said first article comprises solid frusto-pyramidal-shaped elements having a polygonal-shaped cross-section and projecting from said common plane; and said structured surface of said second article comprises surfaces defining a cavity having a polygonal-shaped cross-section and recessed from said common plane.

4. Fastened articles according to claim 3 wherein said polygonal-shaped cross-section of said first article comprises a hexagon and said polygonal-shaped cross-section of said cavity comprises a triangle.

5. Fastened articles according to claim 1 wherein one of said first and second article's tapered elements are constructed from a flexible, polymericmaterial.

6. Fastened articles according to claim 1 wherein said angle between the first and second longitudinal axes is between more than zero (0) degrees and less than about twenty (20) degrees.

7. Fastened articles according to claim 6 wherein said angle is preferably seven and one-half (7.5) degrees.

8. Fastened articles according to claim 5 wherein in an unfastened position, said structure surfaces of said first and second articles comprise solid frusto-pyramidal-shaped elements having a square-shaped cross-section defining a diameter and a top surface defining a height measured from said common plane, and said elements are spaced to define a pitch wherein:
said height is approximately equal to 2.74 times the diameter;
said pitch is approximately equal to 1.43 times the diameter;
the height is measured between the common plane and a top or bottom of the element;
the diameter is measured as the length of the side of square shaped cross sections; and the pitch is equal to the diameter plus a distance between the frusto-pyramidal-shaped elements.

9. A method of fastening articles comprising providing a first article having at least one major surface at least a portion of that surface being a structured surface, said first article's structured surface including a plurality of tapered elements, each element having at least one side inclined relative to a common plane at an angle sufficient to form a taper, and each of said elements having a shape in an unfastened position, situating said first article's plurality of tapered elements to form a plurality of axes including at least one first article longitudinal axis;
providing a second article having at least one major surface at least a portion of that surface being a structured surface, said second article's structured surface including a plurality of tapered elements, each element having at least one side inclined relative to a common plane at an angle sufficient to form a taper, and each of said elements having a shape in an unfastened position;

situating said second article's plurality of tapered elements to form a plurality of axes including at least one second article longitudinal axis;
disposing said first longitudinal axis at an angle relative to said second longitudinal axis; and then pressing said structured surfaces of said first and said second article together such that after said structured surfaces are pressed together, at least one of said tapered elements of said first or said second article is axially bent and torsionally flexed relative to its relaxed, unfastened position, and such that said inclined sides of one of said first and second article's tapered elements are frictionally adhered to at least some of said inclined sides of the other of said first and second article's tapered elements.

10. A method according to claim 9 wherein said step of disposing said first longitudinal axis at an angle comprises the step of disposing said first longitudinal axis at an angle relative to said second longitudinal axis which isbetween more than zero (0) and less than about twenty (20) degrees.

11. A method according to claim 10 wherein said angle is approximately 7.5 degrees.