CA2131879A1

CA2131879A1 - Tricot nonwoven fabric

Info

Publication number: CA2131879A1
Application number: CA002131879A
Authority: CA
Inventors: Susan Lynn Suehr; William F. Kelly; Charles Shimalla; Frank James Flesch; James E. Knox
Original assignee: McNeil PPC Inc
Current assignee: Johnson and Johnson Consumer Inc
Priority date: 1993-09-13
Filing date: 1994-09-12
Publication date: 1995-03-14
Also published as: KR950008772A; HU218618B; RU94033117A; BR9403523A; ZA947014B; CZ289025B6; RU2135660C1; JP2006104657A; FI944199A0; DK0644288T3; US5670234A; DE69423282T2; ES2144489T3; AU693461B2; JP2004353162A; EP0644288B1; ATE190364T1; AU7283594A; CZ220194A3; AU6991998A

Abstract

ABSTRACT

A nonwoven fabric of entangled fibers defining a predetermined pattern of openings with the fabric having excellent draping characteristics.

Description

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Nonwoven fabrics have been ~nown for many years.
¦ Many nonwoven fabrics are produced by forming a web or batt of textile like fibers and treating the fiber batt with blnder to hold fiber~ together and provide some strQngth to the batt. I~ other instances a nonwoven ~( ~abrlc may b~ produced by treating a f~er batt with water streams to cause the fibers to entangle with each other and provide some strength in the batt. Many methods have ,, .
; been developed for treating fiber batts in such a manner in an ~ttempt to duplicate the physical properties and appearance of woven fabrics. While the methods developed for producing non woven fabrics have produced fabrics with ,~ 15 some oP the characteristics of woven or knitted fabric~, , one property, namely drapabillty, has been di~ficult to achieve. None of the nonwoveTl fabrics produced to date have had the appearance, drapability or flexibility of ; tricot knit fabrics.
~, 20 ~i It is an ob~ect o~ ~he present invention t~ produce a nonwoYen fa~ric which emulates the appearance and draping characteristics o~ the tricot knitted ~abric~

It is a further ob~ect of the present invention to produce a very drapable nonwoven fabric having good strength in ~ll directions. Further object3 of the ~,~ present invention will be apparent from the following ;~ detailed description.
; S~mmary of_th~ Present Invention The nonwoven fabrics of the present invention have an upper surface and a lower ur~ace. Disposed between thes~
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~urfa~s~ are a plurality o~ fiber~. The ~iber~ are CHIC~803 , ., :,', ~','`, ,' . ~9l31879 ~ l /
:1 - 2 ; lntertwined and interentangled with each other and de~ine :: a predetermined pattern o~ opening in the nonwoven fabric. A portion of the openings include a fiber segment loop disposed in the opening. The loop comprises a plurality of substantially parallel fiber segments which are in the shape of a U. The open end of the U is . directed towards one sur~ace of the fabric while the closPd end of the U ls directed towards the opposite surface of the fabric. The nonwoven fabrics of the ,~ ~ 10 present invention have excellent drapability and have a drape index in all directions of the fabric of 75 degrees or greater.

Brie~ De~cri~ion of the Drawin~
Figure 1 i8 a photomicrograph of a nonwoYen fabric of the present in~ention enlarged about 20 times, as seen ~rom the upper sur~ace;
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. Figure 2 i~ a photomicrogralph oP a nonwoven fabr1c of ~0 the present invention enlarged ~bout 20 times, as seen fro~ the bottom surface;

Figure 3 is a schematic sec:tional view o~ one type of : apparatu~ for producing the nonwov~n fabrics o~ the present invention;
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Figure 4 i~ a diagrammatic view of another type o , apparatus for producing nonwoven fabrics o~ ~he present lnvention; and Figure 5 i8 a perspective view of one type of . topogra~hical ~upport member that may be used in the apparatus depicted in Figure 4.
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.~ Detailed Description of_the Invent~on e~erring to the drawing~, Figure 1 i~i a photomicrograph of a nonwoven ~abric of the present . invention at an enlargement of approximately 20 times. The ~abric 10 i5 made from a plurality of Pibers. As seen in the photomicrograph, the fibers are intertwined and -; intarentangled and form a pattern of opening3 1~ in the fabric. ~ number of the~e openings include a loop 12 . formed from fiber segments. Each loop is made from a ~ 10 plurality of ~iubstantia~ly parallel fiber segments. The ,; loop i5 in the shape sf a U with the closed end of the U
.; pointed upwardly toward~i the upper ~iurface of the fabric . as viewed in the photomicrograph. Figure 2 is a photomicrograph of the opposite surface o~ the fabric of :L5 Figure 1 at an enlargement of about 20 times. The fibers in the fabric are intertwined and entangled to form a " pattern o~ openings 11 in the .Eabric. In some of these ,, opening~ there are U shaped loop~i 12 ~ormed from i ~ubstantially parallel fiber i~e.gments. When viewed fro~
I:j 20 thi~ bottom ~urface of the fabric, the open end of the U-,. 6haped loop i8 pointed towards the sur~ace o~ the fabric i, . viewed in this photomicrograph.
r, :-~ Figure 3 i6 a ~ichematic cross-sectional view of apparatu~ which may be used to produce fabric~i of the ,~i present invention. The apparatus includes a movable ; conveyer belt 55. Placed on top o~ this belt to move with the belt i~i a topographically configured support member 56. The support member ha~ a plurality of raised three-d~mensional areas. Holes or openings extending through ~` the ~iupport member are disiposed between these threedimensional areas asi will be more fully discussed in :~- conjunction with Figure 5. ~he fiber web 57 to b~ treated : i~ di~posed or supported at the top of the three ,,:
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.dimensional areas. The web may be a web of carded ibers, .:air laid fiber , melt blown fibers or the like. Above the ~.fiber web i~ a manifold 58 for applying ~luid 59, -.-preferably water, through the fibrous we~ as the fibrous .. 5web i~ supported on the support member and mov~d on the ; conveyer belt beneath the manifold. The water may be ..applied at varying pre~sure~. Dispo~ed ben~ath the : conveyer belt i~ a vacuum manifold 60 for removing wa~er ; ~rom the area as the web and support member are passed : 10under the fluid manifold. In operation, the fiber web is ~!~ placsd on the support member and the ~iber web and support ma~ber passed under the fluid manifold. Water is applied :~ to the fibers to wet out the fiber web, as to be certain I the web i~ not moved or disrupted from i s position on the ;~:
: 15eupport member upon further treatment. Thereafter, the ::, support member and web are pa~sed beneath the manifold a series of time~. During thes~ passe~, the pressure o$ the .
: water of the manifold is increased from a ~tarting pressure o~ about 100 psi to pressures o~ 1000 p~i or ~ors. The manifold consi~ts o~ a plurality o~ ori$ices o$
~: from about 4 to 100 or more holes per inch. Preferably, :1: the nu~ber of the holes in the! mani~old is 13 to 70 per inch. The holes may have a dia~meter o~ ~rom 3/looo of an in~h to 10/1000 of an inch.
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. In F$gure 4, thera i~ deplcted an apparatus for ~ continuously producing fabrics ln accordance with the .,.present inventionO The ~chematic representation includes a conveyer belt 80 which ~erve~ as a support member in acoordance with the present invention. The belt i5 continuously moved in a counter-cloc~wise direct~on about ~paced apart ~e~ber~ a~ is well known in the art.
.D$spo~ed above thi~ ~elt i~ a fluid eading manifold 75 .;`conne~tinq a plurality of line~ or groups o~ orifices 81.
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':1 '1 5 Each gr~up ha~ one or mor2 rows o~ e di~meter holei~
with 30 or more ~olee per ~nch. The manifold ia equipped ; with pressure gauqes 88 and control valvss 87 ~or regulating fluid pressure in each line or group of 1 5 ~rifices. Disposed benaath each or~fice line or group i~
,,, . a suction me~ber 82 for removing excess water and to keep : the water ~rom causing undue ~lcoding. The piber web 83 to be treated and formed into a ~abric according to the . present invention is fed to the s~pport member conveyer -~ 10 belt. Water is sprayed through an appropriate nozzle 84 onto the fibrous web to prewet the web and aid in controlling the fibers as they pass under the pressure . manifoldls. A suction box 85 iæ placed beneath the water : nozzle to remove ex~ess water~ The fibrous web passes under the fluid ~eeding mani~old with the manifold preferably having progressively increasing pressure~. ~or i example, the first line o~ holes or orifices may supply !j fluid forces at 100 psi while th~ next line of orifices : may supply fluid forces at a pressure o~ 300 p5i and the : 20 la~t line of orifices may ~lupply flu~d ~orces at a pressure o~ 700 psi. Though 6 lines o~ orifices are shown, the number of line3 Qr rows cP orifices is not critical, but will depend on the width of the web, the spe~d, the pressure used, the number of rows and holes in each line, ete. After pass~ng between the fluid feeding and the suction manifolds, the formed fabri~ is passed over an additional suction box 85 to remove excess water . ~rom the web. ~he ~upport member may be made from relatively rigid material and may comprise a plurality of . 30 ~lat~. Each slat extends aoros~ the width of the conveyer . and ha~ a lip on one side and a shoulder on the opposite ~ide so that the shoulder of one slot engages with the lip of an adjacent slot to allow for movement between adjacent ~lots and allow for thes~ relatively rigid member~ to be CHIC~803 . ~ ,~
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'i I u~ed in the conveyer co~figuration hown in ~igur~ 4.
... Each ori~lce strip co~prise~ one or more row~ of very Pine diameter holes of approximately 7/1900 of an inch. There . are approximately 50 holes per inch across the orifice .. 5 strip.

~ i~ure 5 is a perspective vi~w of one type o~ ~upport member that may be used to produce the fabrlcs of the , . present invention. The member comprises a plate 90 having . 10 a plurality of openings 91 extending through the thickness of the plate. The openings are ~ligned in rows extending , the length and width of the plate. Th~ top portio~ of : each opening has a conical shape 92. The conical shape ~ur~ace~are relatively smooth with varying undulationY a~
seen in the Figure. The ~urface formed from the conical shapes i8 the sur~ace on which 1:he fiber web i~ placed and . treated in accordance with the present invention.
.i :~ Followiny i8 a speciic example of a method for . 20 producing the fabr~ C8 0~ the present invention.
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In thi~ ~xample, the ~tarting web used to make a ,~ ~abric aacording o the present invention comprises 100%
cotton fiber~. The web weighs 2.5 ounce~ per square yard and comprises a 1.5 ounce per sq. yd. randomized web . la~inated on top o~ a l.0 ounces per sq. yd. carded web.
The web i~ prebonded by placing it on a lO0 X 92 mesh bronze belt and passing the web and belt under columnar water iet stream~. The jet ~treams are produced from 0.007 inch diame~er orifice6 arranqed in a row ru~ning in . the transYerSe direction or the width of the web. There are 30 ori.fices per inch. The web is passed under the columnax jet streams at a ~peed of g2 ft/min. Three C~IC 803 .

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r passe~ are made at loO p8ig and 9 pa~es at 900 p8ig~ The web to oriPice spacing i8 0 ~ 75 inchr The pretreated web i~ removed from the belt ~urface, turned over and plac~2td on a forming plate as depicted in Figure 5. 'I'he forming plate and w~b are passed under columnar water jet streams as de~cribed above. The plate and web are passe~ under , the ~et ~tream~ at 90 ft/min. One pass i5 made at 600 psiq and 7 passes at 1400 psig. The resulting fabric is ~r dried on drying cans to remove the water.
~0 As previously mentioned, thP fabrics of the present , invention have excellent drapability in all directions of ; the fabric. While drapability may b~ measured by various techniques, thc drapability of the fabrics of the present invention are measured by taking a 12 i~ch X 12 inch . square of the ~'abric and conditioning it for at least fi hours in a room at a temperature of 70F. and a relative .,.
humidity of' 65 percent. 'rhe conditioned fabric i5 placed on a ~'lat, horlzontal surface and one edge of' the fabric moved over the edge of the surf'ace so that 6 inche~ of the fabric extends beyond the urface edge and i5 unsupported by the surface. The angl~ the ~abric de~l~cts fxom the horizontal surface i8 measured. This angle is called the drape index of the fabric~ Th~ fabrics are tested in the machine direction~ the cross direction and at 45 degrees and 135 degrees from the machine direct~on.
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A comparison of the drapability o~ the fabric~ of the present i~vention with prior art nonwoven fabrics is made~
The fabric of the present invention made as described in ; the previous Examples i6 processed through a binder pad operation and impregnated with 20% acrylic binder pickup ~ ' and dried on drying can~.
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One o~ the comparative prior art iamples is made using thQ ~ame base web o2 2 1/2 ounces per ~quare yard, the web iB treated and formed into a nonwoven fabric a~
il described in U.S. Patent 3,485,706. Another comparative ~ample i5 made u~ing the 2 1/2 ounces per ~quare yard base web. The web i~ treated and foxmed into a fabric as de~cribed in U.S. Patent 5,098,764. The ~abric of the invention described above and the fabrics made as described in U~S. Patent 3,486,1~8 and U.S. Patent 5,098,764 are passed through a jet dyeing proces~i to enhance properties. The process used is a standard dyeing process used on many apparel and home finishing fabrics to soften the fabric and provide uniform color distribution.
Such ~inishing processe~ are standard in the textile industry and are used with many woven, knit and nonwoven , fabrics. The other fabric compared is a commercial entangled nonwoven fabric ~old by DuPont under the trademark Sontara. This ~abric i~ made from polyester and pulp fibers which are not a~ ~tif~ a8 cotton fibers. The . 20 ~a~ric ii commercially finished to enhance so~tness and drapability. Cotton i8 used in the comparison since it ha~ poor drapability as a result of the stiffness properties of cotton. The drape index of each o~ the three ~abrics i8 determined by the drapabllity te~t previously described. Each o the samples i5 tested in the machine direction, the cross~direction, and at 45 and 135 degree~ to the machine direct~on. The sample~ had the ~ollowing drape indic2s:

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Drape Fabric of U.S~ U.S. Sontara Index Present Patent Patent :' Inventlon 3,485,70~ S,098,764 ., _ . . ,_ . .
~. S ~achine 80 65 75 72 ! Direction_ _ ~' Cross 87 85 85 84 :,~ Direction :: .
s . 45 __ ~1 ___ 63 77 66 ~ 10 135 80 _ 63 _ _ 71 66 .~,;.

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~;^ As may be seen from the above table, the fabrics of ::: the present invention have a drapa~ility index of at leas.
75 degrees and pre~erably 80 degrees or more in all ; directions o~ the fabric. Preferably, the drapability of the fabrics of the present invention, in the machine direction, i~ at lea6t 80 degrees and in the cross-direction i9 at least 85 degrees~
` 20 ~aving now dascribed the invention in specific detail and exemplified th~ manner in which it ~ay be carried into :~ practice, it will be readily apparent to those skilled in .~ the art that many variations, applications, modifications, and extensions of the basic principles involved may be . made without departing from its pirit or scope.

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Claims

1. A nonwoven fabric having an upper surface and lower surface, said fabric comprising a plurality of fiber disposed between said surfaces, said fibers being intertwined and interentangled with adjacent fibers to define a predetermined pattern of openings in said fabric, a portion of said openings having a fiber segment loop disposed therein, said loop comprising a plurality of substantially parallel fiber segments in the shape of U
with the open end of the U directed towards one surface of the fabric and the closed end of the U directed towards the other surface of said fabric.

2. A nonwoven fabric according to Claim 1 wherein the loops are disposed in substantially the center of the opening.

3. A nonwoven fabric according to Claim 1 wherein the openings in the fabric are in a pattern of rows with said rows of openings extending in the longitudinal and cross directions of the fabric.

4. A nonwoven fabric according to Claim 3 wherein the loops are disposed in paced apart rows of openings extending in the cross direction of the fabric.

5. A nonwoven fabric comprising a plurality of intertwined and interentangled fibers defining a predetermined pattern of openings in said fabric, said fabric having a drape index in all directions of the fabric of at least 75 degrees.

6. A nonwoven fabric according to Claim 5 having a drape index in all directions of the fabric of at least 80 degrees.

7. A nonwoven fabric according to Claim 5 having a drape index in the machine direction of the fabric of at least 80 degrees and a drape index in the cross direction of the fabric of at least 85 degrees.