US3679535A

US3679535A - Nonwoven fabric comprising discontinuous groups of small holes connected by ribbons defining large holes

Info

Publication number: US3679535A
Application number: US22290A
Authority: US
Inventors: Frank Kalwaites
Original assignee: Johnson and Johnson
Current assignee: Johnson and Johnson
Priority date: 1970-03-24
Filing date: 1970-03-24
Publication date: 1972-07-25
Anticipated expiration: 1989-07-25
Also published as: BE800210Q

Abstract

A nonwoven fabric having a plurality of patterns of groups of fiber segments that alternate and extend throughout the fabric. The first pattern is of yarn-like bundles of fiber segments which define holes or apertures or other areas of low fiber density located in first discontinuous portions of the fabric. These discontinuous portions of the fabric are interconnected by ribbon-like groups of aligned fiber segments that form a second pattern in second discontinuous portions of the fabric.

Description

y 25, 1972 F. KALWAITES 3,579,535

NONWOVEN FABRIC COMPRISING DISCONTINUOUS GROUPS 3 OF SMALL HOLES CONNECTED BY RIBBONS DEFINING LARGE HOLES Filed March 24, 1970 4 Sheets-Sheet. 1

INVENTOR 1 FRANK A444 WA/TES ATTORNEY July 25, 1972 KALWAITES 3,679,535

NONWOVEN FABRIC COMPRISING DISCONTINUOUS GROUPS OF SMALL HOLES CONNECTED BY RIBBONS DEFINING LARGE HOLES Flled March 24, 1970 4 Sheets-Sheet 2 INVENTOR ATTORNEY July 25, 1972 F. KALWAITES 3,679,535

NONWOVEN FABRIC COMPRISING DISCONTINUOUS GROUPS OF SMALL HOLES CONNECTED BY RIBBCNS DEFINING LARGE HOLES 4 Sheets-Sheet 3 Filed March 24, 1970 E M Ln 1 1 M w\ G T INVENTOR /:4/w( /(4L 41/755 July 25, 1972 F. KALWAITES 3,679,535

NONWOVEN FABRIC COMPRISING DISCONTINUOUS GROUPS OF SMALL HOLES CONNECTED BY RIBBONS DEFINING LARGE HOLES Filed March 24, 1970 4 Sheets-Sheet INVENTOR F/PA/VA [K44 h/A/ 7'5 5 ATTORNEY United States Patent NONWOVEN FABRIC IIOMPRISING DISCONTINU- OUS GROUPS OF SMALL HOLES CONNECTED BY RIBBONS DEFINING LARGE HOLES Frank Kalwaites, Somerville, N.J., assignor to Johnson & Johnson Filed Mar. 24, 1970, Ser. No. 22,290 Int. Cl. D04h 1/46, 1/70 U.S. Cl. 161-109 7 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to nonwoven fabrics and more particularly to patterned nonwoven fabrics made from a layer of fibrous material such as a fibrous web wherein the individual fiber elements are capable of moving under the influence of applied fluid forces. The fabric contains a plurality of patterns of different types of groups of fiber segments that alternate and extend throughout the fabric.

BACKGROUND OF THE INVENTION For a number of years, there have been known various type of foraminous or apertured nonwoven fabrics made by processes involving the rearrangement of fibers in a starting web or layer of nonwoven fibers. Some of these fabrics and methods of manufacture are illustrated, shown, and described in US. Pats. 2,862,251; 3,081,500; 3,081,512; 1 3,081,514; 3,081,515; 3,025,585; and 3,033,721. The fabrics disclosed and claimed in the patents just listed contain apertures or holes or other areas of low fiber density which are often outlined by interconnected bundles of fibrous elements wherein the fiber segments within the bundle are closely associated and substantially parallel and have a yarn-like configuration. The term areas of low fiber density is used in this specification and claims to include both areas in which relatively few fibers in comparison to the rest of the fabric are found, and apertures (holes) that are substantially or entirely free or fibers. Such fabrics are sometimes referred to as bundled rearranged nonwoven fabrics.

Bundled rearranged nonwoven fabrics have been made commercially for many years. In most instances, these fabrics have had an overall pattern of holes or other low fiber density areas throughout the fabric.

A method for producing bundled rearranged nonwoven fabric is to support a loose fibrous web or layer on a permeable backing member and apply sets of opposing fluid forces to the layer while thus supported. The fluid by which such forces are applied passes through the fibrous layer, over the backing member, and then through the backing member to pack various groups of the fiber elements and place these elements into closer proximity and substantial parallelism to form interconnected bundles of fiber segments. In accomplishing this result, the fluid forces usually are applied over the entire surface of the loose fibrous web or layer and uniformly over and through the permeable backing or support memberto produce fiber bundles uniformly over the entire fabric. In some instances, patterns can be made in the fabric by not apply- 3,679,535 Patented July 25, 1972 ing fluid forces in predetermined areas of the fibrous layer, thereby preventing rearrangement in these areas.

SUMMARY OF THE INVENTION I have discovered a novel nonwoven fabric which comprises a layer of intermingled fibers with the fibersarranged to form a plurality of patterns that alternate and extend throughout the fabric. The first pattern is of yarnlike bundles of fiber segments which define apertures or holes or other areas of low fiber density in first discontinuous portions of the fabric. Each of the areas of low fiberdensity in the first pattern are defined by a plurality of yarn-like bundles of fiber segments. The fiber segments in each of these bundles are closely associated with other fiber segments in the bundle and lie generally parallel to the longitudinal axis of the bundle. The yarn-like bundles of fiber segments are interconnected to other such bundles at junctures by groups of fibers common to a plurality of bundles. The fibers at these junctures are oriented in a plurality'of diverse directions. 7

The first discontinuous portions of the fabric are interconnected by ribbon-like groups of substantially aligned fiber segments. The interconnecting groups are located in second discontinuous portions of the fabric. The interconnecting groups form a second pattern of aligned fiber segments which will alternate with the first pattern of groups of fiber segments and extend throughout the fabric.

In some embodiments of the present invention, the interconnecting groups of substantially aligned fiber segments in the second discontinuous portions of the fabric define another plurality of holes or apertures or other areas of low fiber density that are located in third discontinuous portions of the fabric.

Surprisingly, even though my new fabric has a plurality of patterns that alternate and extend throughout the fabric, the patterns have substantial regularity which aids in giving the fabric considerable aesthetic appeal. Not only does my new fabric have substantial uniformity in its arrangement of holes or apertures or other areas of low fiber density, but unexpectedly, my new fabric has uniformity in the pattern of bundles of fiber segments which define the areas of low fiber density in the first discontinuous portions of the fabric and in the pattern of ribbonlike groups of substantially aligned fiber segments which interconnect the discontinuous portions of the fabric that form the first pattern.

METHOD OF MAKING THE FABRIC OF THIS INVENTION In the method of making the fabric of this invention, the layer of fibrous starting material is supported in a fiber rearranging zone in which fiber movement in directions parallel to the plane of said fibrous material is permitted in response to applied fluid forces. Streams of rearranging fluid, preferably water, are projected into the fibrous layer at entry zones spaced from each other adjacent one surface of the layer, each of the entry zones having a width at its narrowest part equal to at least about ten times, and preferably about twenty or more times, the average diameter of the fibers of the fibrous starting material. These streams of rearranging fluid are passed through the layer of fibrous starting material as it lies in the rearranging zone, to effect movement of at least some segments of the fibers transverse to the direction of travel of the projected streams.

In the next step of the method, the passage of first portions of the rearranging fluid out of the fibrous layer is blocked at continuous barrier zones located adjacent the opposite surface of the fibrous layer, and, at the same time, those portions of fluid are deflected sidewise toactively mingled with the latter. Each of the barrier zones has a width at its narrowest part equal to at least about the widthof: one of the entry zones at its narrowest part:

All the portions of intermingled rearranging fluid are then passed out of the rearranging zone through spaced, discontinuous,.. foraminous zones defined by the continuous barrierzones and each having an area at least about three times, and preferably about four or more times, the area of one of the entry zones.

I'he passage. of the rearranging fluid through the-layer offibrous starting material as just described moves some of the fiber segments that are in registry with the continuous barrier z'ones into the foraminous zones,and positions those fiber segments with other fiber segments in 'apattern ofyarn-like bundles which define areas of low fiber density in the foraminous'zone. In addition, the rearranging fluid moves other fiber segments that are in registry with the barrier zones into'substantialalignment in flat, ribbon-like groups of fiber 1 segments in bridging positions extending 'between' the discontinuous foraminous zones.

' In onemethod'of manufacturing my new nonwoven fabric, a 'starting layer of fibrous material, the individual fibrous'elem'ents ofwhich are capable of movement under the influence of applied fluid forces, is subjected to fluid rearranging forces, preferably liquid, while the layer is supported on a permeable backing member. The backingmember has a predetermined topography and has foraminous'areas arranged in a discontinuous pattern that are'interconneeted by'continuous imperforate areas. The fluid flowsover and through the foraminous areas and onlyover the imperforate areas. This fluid flow causes counteracting components of force to act to rearrange fibers into groups of yarn-like fiber bundles above the foraminous areas of the backing means. Thisfluidflow also causes components of force to act on the fibrous layer to align 'fiber portions into groups in' accordance with the pattern of imperforate areas of the backing member. These fiber portions generally align themselves in fiat ribbon-like groups in such a manner as to span each imperforate area and connect immediately adjacent portions of the fabric lying abovethe foraminous areas of the backing member. I P

The basic method and apparatus for making the fibers fibers; that isgenerally having a length from about A inch to about 2 to 2 /2 inches. Satisfactory products may be produced in accordance with this invention from starting webs weighing between 80 grains per square yard to 2000 grains per square yard or higher.

' Apertured forming means that-streams of rearranging fluid passingthrough' those apertures will be effective to separate groups of fiber segments intoyarn-like bundles spaced suflicientlyfar apart to permit reliable visualresolution. Without such resolution, any bundle of fiber segments produced would seem to the person viewing the fabric to fuse or'merge together with other such bundles, with the result that :no clear pattern would be apparent in the fabric. To achieve such resolution, the width of each aperture at its narrowest part should be equal to at least about-zten times, and

' preferably at least about twentytimes, the'average diamof this invention -are shown and described fully in my l US. Pat. No. 2,862,251, issued Dec. 2, 1958. Full particulars of the basic invention as disclosed in 'that patentare incorporated in this application by reference,-*although some of those particulars are repeated here. In addition, the specific feature peculiar to the method and apparatus for making the fibers of the present invention-which is the use of a backing memberis described in detail in this application. 1

, Starting material The starting material used with the method or apparatus 7 for making the fabrics of this invention may beany of the standard fibrous webs such as oriented card webs,

isowebs, air-laid webs, or webs formed by liquid deposition. The webs may be formed in a single layer, or by laminating a plurality of the webs together. The fibers in the web may be arranged in a random manner or may be more or less oriented as in a card web. The individual fibers may be relatively straight or slightly bent. The

fibers intersect at various angles to one another such that, generally speaking, the adjacent fibers comefinto contact only at the points where they cross." The 'fiber's are capable of movement under forces applied by fluids such as water, air, etc. I

To produce a fabric having the characteristic hand and drape of a textile fabric, the layer of starting material used mayeomprise natural fibers such as cotton, flax, etc.; mineral fibers such as glass; artificial fibers such as viscose rayon, cellulose acetate, etc.; or synthetic fibers such as the polyamides, the polyesters, the acrylics,'the polyolefins, etc., alone or in combination with one another. The fibers used are those commonly considered textile eter of the fibers in the fibrous starting material.

The land areas of the apertured forming-means that lie between and interconnect the forming-apertures may be either narrow orbroad in comparison to the forming apertures, as desired. Generally speaking, the narrower the land areas are, the more tightly compacted will be the yarn-like bundles of closely associated and substantially parallel fiber segments that are formed beneath those land areas.

' Backing means having discontinuous'foraminous portions As already indicated, in one form of this invention the fibrous starting layer is supported on backing means having foraminous portions arranged in a discontinuous pattern, and continuous imperforate portions'that lie between and interconnect the discontinuous-foraminous portions to provide barrier zones against thepassage of rearranging fluid out of the fiber rearranging .zone. Thewidthof each lmperforate portion of the backing means at its narrowest partis equal to at least about the .width of the narrowest part of an aperture of. the-apertured forming means with which the backingmeanssis used. Theforaminaof the foraminous portions of the backing meansare substantially smaller than the apertures of theapertured form- ]Ilg means. 1 -I l The bridging of the imperforate portions of the backing means by aligned fiber segments referred to above is brought about by three factors-good drainage of the rearranging fluid from the fiber rearranging zonexwith no uncontrolled washing away of fibers, the accumulation and retention of groups of fiber segments at spacedpoints across the backing means, and the pulling taut of other fiber segments that extend betweensuchzgroups and are anchored by them at .a plurality ,of points along their lengths. 1 j r Good drainage is achieved by avoidingthe use of too much rearrangingrfluid and by employing. discontinuous about 30 percent or even more, of the total area of the backing means.

Accumulation and retention of fiber segments at spaced points across the backing means takes place when each foraminous portion of the backing means is large enough that a group of fibers can be accumulated and retained in the form of a plurality of yarn-like bundles of fiber segments which define areas of low fiber density.

The pulling taut of fiber segments between adjacent groups in which they are anchored is achieved by limiting the maximum spacing of the foraminous portions of the backing means. To establish two reliable anchor points for each individual fiber segment, the foraminous portions of the backing means should be spaced from other such portions immediately adjacent thereto by no more than about A the average length of the fibers being rearranged, and preferably no more than about or the length of the fibers. In general, this means that with 1 /2 staple length fibers, each pair of foraminous portions of the backing means should be spaced, at their closest points, no more than about /2" apart, and preferably no more than about A".

In plan view, the discontinuous foraminous portions of the backing means may have any shape desired, i.e., circular, oval, diamond, square, etc.

The discontinuous foraminous portions may be flush with the imperforate portions of the backing means, or at a different elevation. If a three-dimensional effect is desired for the fiber grouping accumulated at each foraminous portion of the backing means, the continuous imperforate portions of the backing means may lie above the foraminous portions by as much as about or slightly higher. This dilference in height must not be too great or it will interfere with the production of a pattern of yarn-like bundles of fiber segments above each discontinuous foraminous portion of the backing means.

In certain methods for producing the fabric of the pres ent invention, each discontinuous foraminous portions of the backing means may be provided with a plurality of protuberances and troughs alternating across its surface in both the longitudinal and transverse directions. The tops of the protuberances should rise above the bottoms of the immediately adjacent troughs by a vertical distance equal to at least about three times the average diameter of the fibers in the layer of fibrous starting material. Preferably, the distance referred to should be equal to about ten times the average diameter of those fibers. When such a backing means is used, the apertured forming means may be eliminated, and the protuberances and troughs will produce a pattern of areas of low fiber density with each area defined by a plurality of yarn-like bundles. If such a backing means is used in conjunction with the apertured forming means, yet another pattern of yarn-like bundles is formed in the areas of low fiber density produced by the apertured forming means.

Rearranging fluid The rearranging fluid for use in making fabrics of this invention is preferably water or a similar liquid, but it may be other fluids such as a gas, as described in my Pat. No. 2,862,251.

If desired, a vacuum may be applied at the exit side of the fiber rearranging zone to assist in moving the rearranging fluid through the fibrous starting material and in rearranging the fibers of the material into a patterned nonwoven fabric. This feature is most useful when the rearranging fluid is a liquid.

Even though some of the rearranging forces applied to the loose fibrous web in making my fabric are considerably different in magnitude than other forces applied to the loose fibrous web, these rearranging forces of disparate magnitude do not conflict or compete with each other but cooperate with and complement each other to produce uniformity and regularity in the areas of low fiber density, the yarn-like fiber bundles, and the interconnecting flat, ribbon-like groups of aligned fiber segments. My new nonwoven fabrics can be made with patterns which simulate fancy woven and knitted fabrics and which even simulate lace, crocheted fabrics and the like.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be more fully describeddn conjunction with the accompanying drawings wherein:

FIG. 1 is a photomicrograph of a fabric of the present invention at an original enlargement of 5 times.

FIG. 2 is a photomicrograph of another fabric of the present invention at an original enlargement of 5 times.

FIG. 3 is a schematic drawing of a fabric in accordance with the present invention.

FIG. 4 is a schematic drawing of another embodiment of the fabric in accordance with the present invention.

FIG. 5 is still another diagrammatic showing of a fabric in accordance with the present invention.

FIG. 6 is a diagrammatic showing in elevation of one type of apparatus for carrying out a method for produc ing the fabrics of the present invention.

FIG. 7 is an enlarged diagrammatic view of a portion of the backing means used in the apparatus of FIG. 6.

FIG. 8 is a cross-sectional view taken along line 8-8 of FIG. 7.

FIG. 9 is an enlarged fragmentary diagrammatic plan view of the foraminous portion of another backing means that can be used with the apparatus of FIG. 6, an aperture of the apertured forming means being shown in dashed lines.

FIG. 10 is a cross-sectional view taken along the line 10-10 of FIG. 5.

FIG. 11 is a cross-sectional view taken along line 1111 of FIGS. 9 and 10.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION Referring to the photomicrograph in FIG. 1, there is shown a nonwoven fabric of the present invention. The fabric 20 includes a plurality of areas of low fiber density 21 in first discontinuous portions 22 of the fabric. The areas of low fiber density are defined by a first regular or predetermined pattern of yarn-like bundles 23 of fiber segments. The yarn-like bundles are interconnected to other such bundles at junctures 24 by fibers common to a plurality of the bundles. The first discontinuous portions of the fabric are interconnected by a second pattern of flat, ribbon-like 25 groups of substantially aligned fiber segments located in second discontinuous portions of the fabric. These interconnecting groups define a plurality of areas of low fiber density 26 in the fabric in third discontinuous portions of the fabric.

Referring to photomicrograph FIG. 2, a very similar fabric to that in FIG. 1 is shown. The fabric 30 has a plurality of areas of low fiber density 31 in first discontinuous portions 32 of the fabric. The areas of low fiber density are defined by a first regular or predetermined pattern of yarn-like bundles 33 of fiber segments, with the bundles being interconnected with other bundles at junctures 34 by fibers common to a plurality of the bundles. The first discontinuous portions of the fabric are interconnected by a second pattern of flat, ribbon-like groups 35 of substantially aligned fiber segments in second discontinuous portions of the fabric. These interconnecting groups form a plurality of areas of low fiber density 36 in third discontinuous portions of the fabric.

The major difference between the fabric shown in FIGS. 1 and 2 is that the fabric in FIG. 1 is made from an oriented card web, that is with the fibers generally aligned in the direction of the arrow shown, whereas fabric shown in FIG. 2 is made from an isoweb, that is, with the fibers randomly oriented. Because of this difference in original orientation, the areas of low fiber of low fiber, density is defined by a first regular or predetermined pattern of yarn-like bundles 43 of fiber segments. The yarn-like bundles 43 of fiber segments are interconnected with other bundles at junctures 44. These discontinuous portions of the fabric are arranged in a staggered pattern over the fabric. I

The first discontinuous portions of the fabric are interconnected by a second regular or predetermined pattern .of flat, ribbon-like groups 45 of substantially aligned fiber segments in second discontinuous portions of the fabric. These groups of fiber segments define areas of low fiber density 46 in third discontinuous portions of the fabric. The groups of fiber'segments are disposed. substantially uniformlyabout the periphery of veach discontinuous portion at about the and 11 oclock positions and the 1 and 7 oclock positions.

' In FIG. 4, there is shown another embodiment of a nonwoven fabric according to the present invention. In this'embodiment, the fabric 50 includes a plurality of areas of low fiber density 51 with the areas of low fiber density defined bya first pattern of yam-like bundles 52 of fiber segments interconnected at junction 53. The areas of low fiber density 51 are disposed in first discontinuous portions 54 of the fabric with the discontinuous portions aligned in a square pattern so that they extend longitudinally and transversely of the fabric. The discontinuousportions of the fabric are interconnected by ribbon-like groups 55 of fiber segments in second discontinuous portions of the fabric that'define a plurality of areas of low fiber density 56 in'third discontinuous fabric portions. The interconnecting'groups contain highly aligned fiber segments. The interconnecting groups of fiber segments are disposed in the longitudinal and transverse directions of the fabric and at substantially the .12, 3, 6, and 9 oclock positions at each of the second discontinuous portions 54 of the fabric.

The disposition of the interconnecting ribbon-like groups of fiber segments will depend upon two factors. One is the original fiber orientation in the starting fibrous web and the other is the pattern of the first discontinuous portions of the fabric. Generally, it can be said that'the fiber segments in the interconnecting groups tend to align themselves in the direction of orientation of the starting fiber web. If an isoweb is used, the orientation inthe starting web has little if any effect on how these fiber .segments align themselves into the interconnecting groups. With regard to the pattern of the first discontinuous portions of the fabric, if'these portions are aligned longitudinally and transversely of the fabric, the

interconnecting groups in the second discontinuous portions of the fabric will be similarly aligned, while if these portions are'staggered,'the interconnecting groups will be disposed diagonally of the fabric. 4

Again, referring to FIG. 4'the areas of low fiber density of 51 in the first discontinuous portions 54 'of the fabric have yet another pattern of yarn-like bundles 57 which extend across the areas of low fiber density of the first pattern. These yam-like bundles 57 interconnect at substantially right angles with each other within the areas of low fiber density in the first pattern.

Referring to the diagrammatic showing in FIG. 5, the first discontinuous portions 60 of the fabric 61 are in a pattern of stripes which extend substantially across the entire width of the fabricm. These stripes comprise areas of low fiber density 62 defined byyarnj-lik'e' bundles 63 of fiber segments. The yam-like bundles are 'con- DESCRIPTION OF MACHINE AND METHOD'FOR MAKING FABRICS OF MY INVENTION FIG. 6 shows one form of apparatus that maybe used to produce the fabrics of the present invention. Full particulars of the basic apparatus of which this apparatus is a specific form, including methods of mounting; rota tion, etc., are described in US. Pat. No.'2,862,'251 issued Dec. 2, -195 8, and are incorporated in the present application by reference and thus need not be described'in ca plete detail here. In view of this reference, the apparatus of FIG. 6 will be described in general terms insofar as'its essential elements are the same as in the patent just men tioned, and as already explained above, the features used to manufacture the novel 7 non-woven fabrics of the present invention will be described in more detail.

The apparatus of FIG. 6 includes a rotatable p'erforated drum suitably mounted on

flanged guide wheels

71 and 72 which are mounted for rotation on

shafts

73 and 74. The 'drum has apertures 75 uniformly spaced over its entire surface. Inside the drum, a stationary manifold 77 to which a fluidis supplied through conduit 78-extends along the full width of the drum. On one side of the manifold is a series of nozzles 79 for directing the fluid toward the drum. r A novelbacking or supporting member 80 arranged to travel with rotatable drum 70 will be described below.

(The term backing member and support member are used interchangeably throughout this-description.) Support member 80, as shown in FIG: 7,- has' a'idiscontinuous pattern of formaminous portions 81 and a'continuous pattern of imperforate portions'82 lying between and interconnecting them.-In'FIG.'"-7,-'the formaminous portions are round and arranged such that'tfour of them lie in a square pattern over the s'urface of member 80: As already indicated above, the foraminous' portions of the backing member may have any shape desired. They may also be arranged in any discontinuous pattern over the'support member; i.e., they may be aligned'longitudinally-and/ or transversely, staggered, etc.

FIG. 8 shows a cross-section of the. backing means of FIG. 7 with a cross-seetion of aperturedforming-drum 70 included. As seen, eachcontinuous imperforate portion 82 of backing means 80 hasa curved top-surfaeethat rises slightly abovethe top surface of fora minons portions 81 of the backing means. Becauseof the curved top surface, central portion 85 rises above edge portions 86. of imperforate portion 82 of the backingmeans. Rotatable drum 70 is solid throughout its area except for forming apertures 75 disposed across its surface; As already indicated above, these forming apertures may have any shape desired. They may also be arranged in any discontinuous pattern over the support member;.i.e., they may be aligned longitudinally and/or transverselyrstag ,gered, etc., with continuous land ar'eas between t hem ln the apparatus of FIG. 6, forming apertures 75 are circular in shape and are arranged such that four'of themlie in a. square pattern over the surface of 70. l

The diameter of circular apertures'75jis"atlleast"'about ten times the average diameter of thefibersin' the fib rous starting material. With fibers of 1 /2 denier, for exam e, the diameter of apertures 75 is 0.015" or'larger. h Backing member 80 passesjabout' 7 0iandi sjeparates from the drum" at guide roll '9 0,"whichrotates on shaft '91. The belt' passes downwardly around guide roll 92, rotating on shaft 93, and then 'rearwardly over' v tic al- 1y adjustable tensioning and traclii'n'g uige' washoutrotating on shaft 99, to be returned about the periphery of the drum.

Drug 70 and backing belt 80 provide a rearranging zone between them through which a fibrous starting material may move to be rearranged, under the influence of applied fluid forces, into a non-woven fabric having a plurality of patterns of fiber segments that alternate and extend throughout its area.

Tension on backing belt 80 is controlled and adjusted by the tensioning and tracking guide roll. The guide rolls are positioned in slideable brackets which are adjustable to assist in the maintenance of the proper tension of the belt. The tension required will depend upon the weight of the fibrous web being treated and the amount of rearrangement and patterning desired in the final product.

Forming drum 70 rotates in the direction of the arrow shown, and backing belt 80 moves in the same direction at the same peripheral linear speed and within the indicated guide channels, so that both longitudinal and lateral translatory motion of the backing means, the apertured forming means, and the fibrous layer with respect to each other are avoided. The fibrous material 100 to be treated is fed between the drum and backing member 80 at point A, passes through a fiber rearranging zone where fluid rearranging forces are applied to it, and is removed in its new, rearranged form as non-woven fabric 101 between the drum and belt at point B."

As fibrous material 100 passes through the fiber rearranging zone, a liquid such as water is directed against the inner surface of forming drum 70 by nozzles 79 mounted inside the drum, the water passes through apertures 75 of forming means 70 into the layer of fiborus starting material 100 to produce rearrangement of the fibers of the web, and the water thence passes through foraminous portions 81 of backing means 80.

Vacuum assist box 102 is located against the outside surface of backing means 80. Vacuum box 102 has a slotted surface located closely adjacent the outer surface of belt 80, and through which suction is caused to act upon the web. Suction thus applied assists in the rearrangement of the fibers as the web material passes through the rearranging zone. In addition, it serves to help de-water the web and prevent flooding during fiber rearrangement. Vacuum box 103 located below drum 70 also helps dewater the web after it is rearranged.

In the apparatus of FIG. 6, the relative positioning of rotatable backing drum 70 and apertured forming means 80 with respect to the fibrous layer 100 being rearranged is maintained through the rearranging zone as explained above by guarding against either longitudinal or lateral translatory movement. This maintains the integrity of the rearranged fabric as it is subjected to fluid forces from the rearranging liquid.

The directions the streams of rearranging fluid projected through apertures 75 of drum 70 take as they move into and through the fibrous web determine the type of forces applied to the fibers and in turn, the extent of rearrangement of the fibers. Since the directions the streams of rearranging fluid take after they pass through apertuers 75 are determined by foraminous portions 81 and imperforate portions 82 of backing means 80, it follows that the patterns of these portions of the backing means help determine the patterns of fiber arrangement, as wellas the patterns of holes or other areas of low fiber density, in the resultant fabric.

With imperforate portions 82 raised only slightly above the foraminous portions of the backing means, it has been found that satisfactory formation of yam-like bundles of fiber segments in the first pattern with areas of low fiber density delineated between the yam-like bundles, can be achieved with a fibrous starting material made up of fibers of 1V: denier that has a web weight of no more than about 600 grains per square yard, or somewhat heavier for higher denier fibers. With a similar backing means and a fibrous starting material comprisedof fibers of 1 /2 10 denier of web weight of more than about 800 grains per square yard, it is ordinarily not possible to form such a pattern. The web weights in question may be somewhat higher for this kind of fiber rearrangement, the higher the continuous imperforate portions rise above the discontinuous foraminous portions of the backing means.

FIG. 9 gives an enlarged fragmentary diagrammatic plan view of the foraminous portion of another backing means that can be used with the apparatus of FIG. 6. Foraminous portion 110 of the backing means for use in this invention is formed of coarse woven screen, preferably metal. In the embodiment shown, wires 111 running vertically in FIG. 9 are straight, while wires 112 running horizontally in that figure weave alternately over and under wires 111. Protuberances 113 are present throughout foraminous portion 110 as the topmost part of each knee of a given strand 112 of the screen that is formed as the strand weaves over and under the strands 111tha lie perpendicular to it. p

As a given strand 112 slants downward to pass under a strand 111 perpendicular to it, it crosses two other strands 112 disposed on either side of it, as those strands slant upward to pass over the same perpendicular strand that the given strand will pass under. Each series of such crossing points 114 forms a trough, such as trough 115 formed by crossing points 114 in FIGS. 9 and 10, that lies between adjacent protuberances 113. The effective shape of troughs 115, as can be best seen in FIG. 10 (which shows a cross-section of element 110 of which a plan view is given in FIG. 9), is substantially an inverted triangle.

A series of slightly deeper troughs 116 is formed between adjacent protuberances 113 but extending at right angles to troughs 115. As best seen in FIG. 11, the bottom of each trough 116 is formed by portions of straight strands 111, with successive protuberances 113 on each side of the trough forming the tops of the trough. As seen in FIG. 11, the effective shape of troughs 116 may be characterized as a shallow U-shape.

As shown in FIG. 9, a plurality of troughs 115 and a plurality ofprotuberances 113 alternate in one direction across the surface of foraminous portion 110 of the backing means. FIG. 9 also shows that a plurality of troughs 116 and a plurality of protuberances 113 alternate in a direction perpendicular to troughs 115. Hence a plurality of troughs and a plurality of protuberances alternate in both the longitudinal and transverse directions across the surface of foraminous portion 110 of the backing means.

Use in the apparatus of FIG. 6 of a backing means having foraminous portions such as element 110 shown in FIGS. 9 through 11 produces a third pattern of rearranged fibers within the areas of low fiber density of the first'pattern corresponding to the apertures 75 in drum 70, such as is depicted in FIG. 4. This pattern within the first pattern is made up of yam-like bundles of fiber segments that have been positioned in troughs 115 and troughs 116 on the surface of foraminous portion 110 of the backing means.

If desired, a backing means such as element 110 may be used to produce the fabrics of the present invention by eliminating the apertured forming drum and projecting the rearranging fluid directly onto the fibrous web while it is supported on such a backing means. In such a method, the yam-like bundles of fiber segments which define the areas of low fiber density in the first pattern have been positioned in the troughs 115 and troughs 116 on the surface of the foraminous portions 110 of the backing means.

To produce satisfactory rearrangement of fibers into yarn-like bundles of closely associated and substantially parallel fiber segments positioned in troughs 115 and in troughs 116, the vertical distance between the tops of protuberances 113 and the bottoms of the immediately adjacent troughs should be at least about three times, generally no more than about 15 to 20 times, and preferably and web strength is measured at substantially the same magnitude in every direction throughout the web. The web contains viscose rayon fiber approximately 1%," long and 1% denier.

The fabric of FIG. 2 is generally similar to the fabric of Example 1. I

Example 3 The starting material for this example is the same as in Example 2. Apertured forming drum 70 used in this example is the same as that in Example 1.

Backing means 80 in the apparatus of this example includes in part a smooth surfaced flexible plastic having foraminous circular portions distributed across its surface in a square pattern. Disoontinuous foraminous portions 81 of backing drum 80 are comprised of a woven fiber glass screen of approximately 14 x 18 mesh or substantially 252 openings per square inch. Each of these foraminous portions has a diameter of approximately 4", with a space of approximately from each portion 81 to the nearest other portion 81 in a diagonal direction. Discontinuous foraminous portions 81 are interconnected by the continuous plastic portions of the backing belt.

Foraminous portions 81 of backing means 80 are formed as shown in FIG. 9 through 11. The vertical distance between the tops of protuberances 113 and troughs 115 such as shown in FIGS. 9 and 10 is approximately 0.005", or in other words a little more than three times the 0.0015" average diameter of the 1 /2 denier fibers making up the starting material for this example. The same vertical distance for troughs 116 such as those shown in FIG. 11 is slightly larger.

The horizontal distance between the tops of protuberances 113 is about 0.056" in one direction and about 0.071" in the other. These distances are equal, respectively, to about 37 times and about 47 times the 0.0015" average diameter of the fibers of the fibrous starting material. Each aperture 75 spans a plurality of protuberances 113 on the backing screen, measured in both the longitudinal and the transverse directions. Apertured forming drum 70 and backing belt 80 are spaced from each other during use of the apparatus of FIG. 6 to provide a fiber rearranging zone therebetween.

Use of the apparatus of this example produces a non- I woven fabric having a plurality of patterns of fiber segments that alternate and extend throughout the fabric.

As seen in the schematic drawing of FIG. 4, nonwoven fabric 50 has a first pattern of yarn-like bundles of fiber segments 52 that define areas of low fiber density 51 all located within groups of fiber segments 54 arranged in accordance with the arrangement of discontinuous .foraminous portions 81 of backing means 80. A second pattern of flat, ribbon-like groups of substantially aligned fiber segments 55 interconnects the portions of the fabric in the first pattern.

A third pattern of smaller yarn-like bundles of fiber segments 57 is positioned in

troughs

115 and 116 of the foraminous portions of the backing means. These yarnlike bundles, lying within areas of low fiber density 51, subdivide those areas further into still smaller areas of low fiber density.

The above detailed description has been given for clearness of understanding only. No unnecessary limitations should be understood therefrom, as modifications will be obvious to those skilled in the art.

What is claimed is:

1. A nonwoven fabric with a plurality of patterns of groups of fiber segments that alternate and extend throughout said fabric which comprises: a first pattern of yarn-like bundles of fiber segments defining a plurality of areas of low fiber density, said bundles being located in first discontinuous portions of the fabric, the fiber segments in each of said bundles being closely associated with other fiber segments in the bundle and lying generally parallel to the longitudinal axis of the bundle, each of said yarn-like bundles of fiber segments being interconnected with other such bundles at junctures by groups of fibers common to a plurality of bundles, the fibers at said junctures being oriented in a plurality of diverse directions, each pair of immediately adjacent first discontinuous portions of the fabric being interconnected by a ribbon-like group of substantially aligned fiber segments, said ribbon-like groups being located in second discontinuous portions of the fabric.

2. The nonwoven fabric of claim 1 in which each of said first discontinuous portions of the fabric extends continuously through the fabric in a given direction and is parallel to and spaced from similar portions of the fabric, and in which each of said ribbon-like groups of substantially aligned interconnecting fiber segments also extend continuously through the fabric in said given direction.

3. The nonwoven fabric of claim 1 in which said ribbons of interconnecting fibers define a plurality of areas of low fiber density in third discontinuous portions of the fabric.

4. The nonwoven fabric of claim 3, in which the areas of low fiber density in said first discontinuous portions of the fabric are apertured substantially free of fibers.

5. The nonwoven fabric of claim 3 in which the areas of low fiber density in said third discontinuous portions of the fabric are apertures substantially free of fibers.

6. The nonwoven fabric of claim 3 in which other, smaller yarn-like bundles of fiber segments formed in the same manner as said first-mentioned yarn-like bundles of fiber segments extend across the areas of low fiber density in said first discontinuous portions of the fabric.

7. The nonwoven fabric of claim 6 in which said other, smaller yarn-like bundles of fiber segments are interconnected in the manner aforesaid with similar yarn-like bundles extending substantially at right angles thereto across the areas of low fiber density in said first discontinuous portions of the fabric.

References Cited UNITED STATES PATENTS 3,485,706 12/1969 Evans 161-169 X 3,081,515 3/ 1963 Griswold et al. 28-78 3,033,721 5/1962 Kalwaites 161-150 3,486,168 12/1969 Evans et al. 161-169 2,862,251 12/1958 Kalwaites 19-161 3,353,225 11/1967 Dodson et al. 19-161 3,403,862 10/1968 Dworjanyn 239-566 3,434,168 3/1969 Summers 28-72.2 3,485,708 12/ 1969 Ballou et al. 161-72 3,494,821 2/ 1970 Evans 161-169 3,498,874 3/1970 Evans et al. 161-169 X ROBERT F. BURNETT, Primary Examiner R. L. MAY, Assistant Examiner