US3681182A - Nonwoven fabric comprising discontinuous large holes connected by fiber bundles defining small holes - Google Patents

Abstract

A NONWOVEN FABRIC HAVING A PLURALITY OF PATTERNS OF APERTURES OR HOLES OR OTHER AREAS OF LOW FIBER DENSITY WHICH ALTERNATE AND EXTEND THROUGHOUT THE FABRIC. ONE OF THE PATTERNS OF AREAS OF LOW FIBER DENSITY IS DEFINED BY YARN-LIKE BUNDLES OF FIBER SEGMENTS AND THE OTHER PATTERN OF AREAS OF LOW FIBER DENSITY IS ALSO DEFINED BY YARN-LIKE BUNDLES OF FIBER SEGMENTS. THE FIRST PATTERN OF AREAS OF LOW FIBER DENSITY IS DISPOSED IN DISCONTINUOUS PORTIONS OF THE FABRIC AND THE SECOND PATTERN OF AREAS OF LOW FIBER DENSITY IS DISPOSED IN CONTINUOUS PORTIONS OF THE FABRIC LYING BETWEEN EACH PAIR OF ADJACENT AREAS OF LOW FIBER

DENSITY IN THE FIRST PATTERN. THE AREAS OF LOW FIBER DENSITY IN THE FIRST PATTERN ARE AT LEAST FOUR TIMES LARGER THAN THE AREAS OF LOW FIBER DENSITY IN THE SECOND PATTERN. SOME OF THE YARN-LIKE BUNDLES OF FIBER SEGMENTS IN THE FABRIC ARE OF HEAVIER WEIGHT THAN OTHER SUCH BUNDLES.

Description

Augl, 1972 F. KALWAITES 3,681,182

' NONWOVEN FABRIC COMPRISING DISCONTINUOUS LARGE HOLES CONNECTED BY FIBER BUNDLES DEFINING SMALL HOLES Filed March 24, 1970 8 Sheets-Sheet 1 INVENTOR 6/ fk/lA/K AfMn A/n-s ATTORNEY Aug. l,- 1972 F. KALWAITES 3,681,182 NONWOVEN FABRIC COMPRISING DISCONTINUOUS LARGE HOLES CONNECTED BY FIBER BUNDLES DEFINING SMALL HOLES Filed March 24, 1970 8 Sheets-Sheet 2 NVENTOR fk'A/vk 4414041755 1, 1972 F. KALWAITES 3,681,132

NONWOVEN FABRIC COMPRISING DISCONTINUOUS LARGE HOLES CONNECTED BY FIBER BUNDLES DEFINING SMALL HOLES Filed March 24, 1970 8 Sheets-Sheet 5 INVENTOR flaw/K fifun A/rzs Aug. 1, 1972 F! w rrEs 3,681,182

NONWOVEN FABRIC COMPRISING DISCONTINUOUS LARGE HOLES CONNECTED BY FIBER BUNDLES DEFINING SMALL HOLES Filed March 24, 1970 v 8 Sheets-Sheet 4 ATTORNEY Aug.- 1, 1972 F. KALWAITES 3,581,132

NONWOVEN FABRIC COMPRISING DISCONTINUOUS LARGE HOLES CONNECTED BY FIBER BUNDLES DEFINING SMALL HOLES Filed March 24, 1970 a Sheets-Sheet 5 INVENTOR Flay/r A744 1144/ 715's ATTB NEY 1, 1972 KALWIIHTES 3,681,182

' Filed March 24, 1970 I NONWOVEN FABRIC COMPRISING DISCONTINUOUS LARGE HOLES CONNECTED EY'FIBER BUNDLES DEFINING SMALL HOLES I 8 Sheets-Sheet 6 O O O O O O "EO'OOO 'OOO oo oo'oo ATTORNEY 1. 1972 F. KALWAITES 3,681,182

NONWOVEN FABRIC COMPRISING DISCONTINUOUS LARGE HOLES CONNECTED BY FIBER BUNDLES DEFINING SMALL HOLES Filed March 24, 1970 8 Sheets-Sheet 7 T 3- mm 90 /0/ I M INVENTORI [RANK Mum/r55 ATTORNEY.

Aug. 1, 1972 F. KALWAITES 3,581,132

'NONWOVEN FABRIC COMPRISING DISCONTINUOUS LARGE HOLES CONNECTED BY FIBER BUNDLES DEFINING SMALL HOLES Filed March 24, 1970 8 Sheets-$heet 8 United States PatentO NONWOVEN FABRIC COMPRISING DICONTINU- OUS LARGE HOLES CONNECTED BY FIBER BUNDLES DEFINING SMALL HOLES Frank Kalwaites, Somerville, N.J., assignor to Johnson & Johnson Filed Mar. 24, 1970, Ser. No. 22,289 Int. Cl. D04h 1/46, 1/70 US. Cl. 161-109 16 Claims ABSTRACT OF THE DISCLOSURE A nonwoven fabric having a plurality of patterns of apertures or holes or other areas of low fiber density which alternate and extend throughout the fabric. One of the patterns of areas of low fiber density is defined by yarn-like bundles of fiber segments and the other pattern of areas of low fiber density is also defined by yarn-like bundles of fiber segments. The first pattern of areas of low fiber density is disposed in discontinuous portions of the fabric and the second pattern of areas of low fiber density is disposed in continuous portions of the fabric lying between each pair of adjacent areas of low fiber density in the first pattern. The areas of low fiber density in the first pattern are at least four times larger than the areas of low fiber density in the second pattern. Some of the yarn-like bundles of fiber segments in the fabric are of heavier weight than other such bundles.

BACKGROUND OF INVENTION For a number of years there have been known various types of foraminous or apertured, nonwoven fabrics made by processes involving the rearrangement of fibers in a starting web or fabric of nonwoven fibers. Some of these fabrics and methods of manufacture are illustrated, shown, and described in U.S. Pats. 2,862,251; 3,081,500; 3,081,- 512; 3,081,514; and 3,081,515. The fabrics disclosed and claimed in the patents just listed contain apertures or holes or other areas of W fiber density, 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 of 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 fabrics is to support a loose fibrous web or layer on a permeable backing member and apply sets of opposing fiuid 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 fiuid 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 member to produce fiber bundles uniformly over the entire fabric. In some instances, patterns can be made in the fabric by not applying fluid forces to predetermined areas of the fibrous layer, thereby preventing rearrangement in these areas.

{SUMMARY OF INVENTION I have discovered a novel nonwoven fabric which comprises a layer of intermingled fibers with the fibers arranged to define or outline a plurality of patterns of apertures (holes) or other areas of low fiber density. The first pattern of areas of low fiber density is defined by yarn-like bundles of fiber segments, and the areas are disposed in predetermined discontinuous portions of the fabric. The second pattern of areas of low fiber density is also defined by yarn-like bundles of fiber segments. The second pattern of areas is disposed in predetermined continuous portions of the fabric. Each area of low fiber density in the first pattern is at least four times larger than an area of low fiber density in the second pattern and may be as many as a few thousand times larger than an area of low fiber density in the second pattern. 'Preferably, each area of low fiber density in the first pattern is from ten to a hundred times larger than an area of low fiber density in the second pattern.

The relative dimensions of the large and small areas of low fiber density are also important. The largest dimension across each area of low fiber density in the first pattern should be at least about two times larger than the largest dimension across each area of low fiber density in the second pattern and may be as much as fifty or a hundred times larger than the largest dimension across 1 each area of low fiber density in the second pattern.

Preferably, the largest dimension across each area of low fiber density in the first pattern is from about three to ten times larger than the largest dimension across each area of low fiber density in the second pattern.

The fiber segments in the yarn-like bundles in the fabric are in substantial parallelism and in overlapping relation .ship with one another. The yarn-like bundles are interconnected with other such bundles at junctures by fibers common to a plurality of bundles. The fiber segments in the juncturm are interentangled and extend in various directions.

In certain embodiments of the present invention, some of the yarn-like bundles are substantially heavier than other yarn-like bundles. In those embodiments wherein heavier yarn-like bundles are present, the heavier bundles may be disposed in various manners such as in the direction of orientation of the fibers, or about a portion of the periphery or the entire periphery of the first pattern of larger holes or other areas of low fiber density.

Surprisingly, in my new fabric, even though it has a plurality of patterns which extend throughout the fabric, and the plurality of patterns involve holes or other areas of low fiber density of great difference in size, the patterns have substantial regulartiy and aid in providing a fabric' having considerable aesthetic appeal. Furthermore, not only does my new fabric have subtsantial uniformity in its various patterns of holes or other areas of low fiber density, but unexpectedly, my new fabric has uniformity in the patterns of bundles of fiber segments which define the areas of low fiber density.

3 METHOD OF MAKING THE FABRIC OF THIS INVENTION In manufacturing my new nonwoven fabric, a starting layer of fibrous material the individual fibrous elements of which are capable of movement under the influence of applied fluid forces, is subjected preferably to liquid forces while the layer is supported on a water-permeable backing member. The backing member has a predetermined topography and has foraminous and imperforate areas arranged in a pattern over its surface. The fluid flows over and through the foraminous areas and only over the imperforate areas. This fluid flow causes counteracting components of force to act in certain areas of the fibrous layer to rearrange fibers into yarn-like fiber bundles. This fluid flow also causes other components of force to act on the fibrous layer to align fiber portions into groups in accordance with the pattern of imperforate areas in the backing member. In some instances, the fiber portions may align themselves into bundles immediately adjacent a portion of the periphery of the imperforate areas. In many instances, the fluid forces may be sufiicient to form openings or holes in the fibrous layer that are substantially free of fiber segments.

In the method and apparatus for making the fabrics of this invention, the fibrous starting layer is supported on a foraminous backing means having imperforate portions arranged in a discontinuous pattern, an apertured forming means is positioned above the fibrous layer, and streams of rearranging fluid, preferably water, are projected through the apertures of the apertured forming means and against the fibrous starting material. The remainder of the backing means, other than the discontinuous imperforate portions, is foraminous and readily permeable to the fluid streams used in fluid rearrangement and these foraminous portions of the backing means lie between and interconect the discontinuous imperforate portions. The apertures of the apertured forming means are substantially larger than the foramina in the foraminous portions of the backing means.

The basic method and apparatus for making the fabrics of this invention are shown and described fully in my US. Pat. No. 2,862,251, issued Dec. 2, 1958. Full particulars of the basic invention as disclosed in that patent are incorporated in this application by reference, although some of those particulars are repeated here. In addition, the specific features peculiar to the method and apparatus for making fabrics of the present invention are given in this application.

Starting material.The starting material used with the method or apparatus for making the fabrics of this invention, may be any 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 come into contact only at the points where they cross. The fibers are capable of movement under forces applied by fluids such as water, air, etc.

To produce a fabric having the characteristic hand and drape of a textile fabric, the layer of starting material used may comprise 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 fibers; that is, generally fibers having a length from about inch to about 2 to 2 /2 inches. Satisfactory products may be produced in accordance with this invention 4 from starting webs weighing between grains per square yard to 2,000 grains per square yard or higher.

Apertured forming means-The apertured forming means used with the method and apparatus for making fabrics of this invention is solid throughout its area except for the forming apertures disposed longitudinally and transversely across the member. The forming apertures must be substantially larger in area than the foramina in the foraminous portions of the backing means. The forming apertures may have any desired shape, i.e., round, square, diamond, oblong, free form, etc.

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

Backing means.--As already indicated, the fibrous starting layer is supported on backing means having discontinuous imperforate portions, and continuous foraminous portions that lie between and interconnect the discontinuous imperforate portions.

With a fibrous starting material having fiber lengths in common use, good results may be obtained with openings in the foraminous portions of the backing means from about 900 openings per square inch to about 50,000 openings per square inch, or more, preferably from about 10,000 openings to 40,000 openings per square inch. With a starting material including fibers of longer staple lengths, the number of openings in the foraminous members in question may be as low as 150 per square inch or even lower.

Each discontinuous portion of the backing means should have an area at least about four times, and preferably from about 10 times to about times, as great as the area of an aperture of the apertured forming means. The area of each discontinuous portion may, if desired, be as much as a few thousand times, and even up to 10,000 times, as great as the area of an aperture of the forming means. When heavier webs are employed as the starting material for this invention, i.e., Webs weighing between about 1,000 to 2,000 grains per square yarn, the area of each discontinuous portion of the backing means should be only about 500 to 1,000 times the area of an aperture of the forming means, in order to avoid matting of a large number of fibers around the periphery of the hole in the resulting fabric corresponding to the discontinuous portion of the backing means, with consequent obliteration of the small holes in the fabric that correspond to the apertures of the apertured forming means.

Improved results are obtained if each discontinuous imperforate portion of the backing means, whatever its precise shape may be, is a. fairly compact area having a maximum dimension not much greater than its smallest dimension. Thus, improved results are produced if the maximum dimension of discontinuous imperforate portion is no greater than about four times the minimum dimension, and still further improvement is produced if the maximum dimension is no more than about one-andone-half times the minimum dimension of each such portion.

The maximum dimension of each discontinuous imperforate portion of the backing means should be substantially less than the staple length of the fibers in the fibrous starting material, for example, not more than one inch maximum dimension, and preferably not more than /s to /2 maximum dimension, when fibers having an inch-and-a-half staple length are employed. If one dimension of a discontinuous portion of the back means is made smaller, the other may be increased.

The larger the dimensions of the discontinuous imperforate portions of the backing means, the more likely it is that some fiber segments will not be moved otf those imperforate portions during fiber rearrangement but will remain there to lie in areas of low fiber density in the resulting fabric that correspond to the discontinuous imperforate portions of the backing means. If the imperforate portion is longer than it is wide, and the longer dimension extends in the direction of fiber orientation in the layer of fibrous starting material, more fiber segments will be moved oif the imperforate portion. On the other hand, if the larger dimension of such an imperforate portion of the backing means extends perpendicular to the direction of fiber orientation, more bridging of fibers across the imperforate portion of the backing means will result. In any event, and regardless of all other factors, all loose ends of fibers in the layer of fibrous starting material that are positioned above the imperforate portions of the backing means will be washed off those imperforate portions by the fiuid rearranging forces applied to the fibrous material.

The discontinuous imperforate portions of the backing means may be flush with the plane of the top surfaces of the foraminous portions of the backing means, but for improved results they rise at least by about 4 above the plane of that surface and preferably by about to A The height of the discontinuous imperforate portions should generally be no more than about A, but for heavier webs may be somewhat higher. When relatively heavy starting webs of fibrous material are employed, a greater height for the discontinuous imperforate portrons of the backing means produces clearer formation of areas of low fiber density in the resulting fabric. In other words, increased height for the discontinuous imperforate portions produces more pronounced formation of yarn-like bundles of fiber segments at the periphery of the areas of low fiber density which are formed in the resulting fabric above the imperforate portions of the backing means. However, if the imperforate portions are raised too high in relation to the fiber density of the fibrous starting material, flooding is produced, and there is a resulting lack of controlled formation of yarn-like bundles of fiber segments in the fabric produced.

In plan view, the discontinuous portions of the backing means may have any shape desired, i.e., circular, oval, diamond, square, crescent, half-moon, lace-like, freeform, etc.

The discontinuous imperforate portions of the backing means should have walls that are vertical or taper out in a downward direction. The edges are preferably slightly rounded, but not excessively so. In any case, the top of' the discontinuous portions should be smooth, in order not to interfere with fiber rearrangement.

If an additional pattern of holes or other areas of low fiber density is desired in the fabric produced by use of the method or apparatus of this invention, the continuous foraminous portions of the backing means should be provided with a plurality of protuberances and troughs alternating across their surface in both the longitudinal and transverse directions. As illustrated in the drawings below, the top of the protuberances should rise above the bottoms of the immediately adjacent troughs by a vertical distance equal to at least about three times, but generally no more than about to times, the average diameter of the fibers in the layer of fibrous starting material. Preferably, the distance should be equal to about five to about ten times the average diameter of those fibers. The protuberances should not rise so far above their immediately adjacent troughs as to disrupt formation of the pattern of areas of low fiber density corresponding to the apertures of the apertured forming means.

Another technique for forming an additional pattern of holes or other areas of low fiber density in the fabric, i.e., a third pattern, is to connect the discontinuous imperforate portions of the backing member with imperforate portions which are approximately as wide as or somewhat 'wider than an aperture in the apertured forming means. For example, if diameter holes are used as apertures in the apertured forming means and the discontinuous imperforate portions are connected by Ms wide to A" wide imperforate ribs, a third pattern will result, i.e., one pattern corresponding to the discontinuous imperforate portion, a second pattern in the foraminous portion and a third pattern in the connecting rib portion.

During use of the method or apparatus, the apertured forming means and the backing means are spaced from eachother to provide a fiber rearranging zone in which fiber movement in directions parallel to the backing means is permitted in response to applied fluid forces.

Rearranging fiuid.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.

The higher the pressure employed, the larger the quantity of water that is delivered, and as a resultany heavier yarn-like bundles of fiber segments that may extend through the resulting fabric are not so likely to lie immediately adjacent the larger areas of low fiber density in the portions of the fabric that overlie the discontinuous portions of the backing means.

Even though some of the rearranging forces applied to the loose fibrous web in making my fabric are considerably different 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 and regularity in both the patterns of areas of low fiber density produced and the fiber bundles produced. 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 described in 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 photomicrograph of a cross-sectional view of the fabric of FIG. 2 at an original enlargement of 10 times.

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

FIG. 5 is a schematic drawing of another embodiment of a fabric in accordance with the present invention.

FIG. 6 is a schematic drawing of a fabric in accordance with the present invention made from an isoweb as the starting material.

FIG. 7 is a schematic drawing of another embodiment of a fabric in accordance with the present invention.

FIG. 8 is a photomicrograph of a fabric of the present invention at an original enlargement of 5 times.

FIG. 9 is a photomicrograph of a fabric of the present invention at an original enlargement of 5 times.

FIG. 10 is a photograph of another fabric in accordance with the present invention.

FIG. 11 is a schematic drawing showing the minimum relative size of the areas of low fiber density in the first and second pattern of areas.

FIG. 12 is a schematic drawing showing a preferred relative size of the areas of low fiber density in the first and second pattern of areas.

FIG. 13 is a diagrammatic showing in elevation of one type of apparatus for carrying out the method for producing the fabrics of the present invention.

FIG. 14 is an enlarged diagrammatic view of a portion of the support member used in the apparatus of FIG. 13, and FIG. 14a is a transverse section.

FIG. 15 is an enlarged fragmentary diagrammatic plan view of the foraminous portion of another backing means that can be used with the apparatus of FIG. 13, an aperture of the apertured forming means being shown in dashed lines.

FIG. 16 is a cross-sectional view taken along the line 16-16 of FIG. 15.

FIG. 17 is a cross-sectional view taken along the line 17-17 of FIGS. 15 and 16.

FIG. 18 is a photomicrograph of another fabric of the present invention at an original enlargement of times.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION Referring to the photomicrograph, FIG. 1, there is shown a nonwoven fabric 20 of the present invention. The fabric comprises a first regular or predetermined pattern of areas of low fiber density 21, and a second regular or predetermined pattern of areas of low fiber density 22. The first pattern is disposed in what are termed discontinuous portions of the fabric, whereas the second pattern is disposed in continuous portions of the fabric. Each of the areas of low fiber density in the first pattern is defined by a plurality of yarn-like bundles of fiber segments 23.

These yarn-like bundles of fiber segments are interconnected with other such bundles at junctures 24. The second pattern of the areas of low fiber density is also defined by yarn-like bundles of fiber segments 25 which are interconnected at junctures 26. The areas of low fiber density 21 in the first pattern are several times larger than the areas of low fiber density 22 in the second pattern.

The fabric shown in FIG. 1 was made from an oriented card web with the direction of orientation of the fibers being predominantly in the longitudinal direction of the fabric as shown by the arrow. In the fabric, the fiber bundles 28 especially those which appear larger and heavier, have a general direction of orientation in the longitudinal direction of the fabric.

With regard to the photomicrograph, FIG. 2, the fabric 30, has a first pattern of areas of low fiber density 31 and a second pattern of areas of low fiber density 32, with the areas of low fiber density in the first pattern being several times larger than the areas of low fiber density in the second pattern. The areas of low fiber density in the first pattern are defined by yarn-like bundles of fiber segments 33, interconnected at junctures 34. The areas of low fiber density in the second pattern are defined by yarn-like bundles of fiber segments 35, interconnected at junctures 36. The fabric of FIG. 2 was made using an isoweb; that is, with no predominant direction of fiber orientation.

In the cross-sectional photomicrograph, FIG. 3, which is a cross-section of the fabric 30 of FIG. 2, there are shown yarn-like bundles 35 which define the second pattern of areas of low fiber density 32 and the yarn-like bundles 33 which define the first pattern of areas of low fiber density.

The various yarn-like bundles will be more fully described in conjunction with the schematic showing in FIGS. 4, 5, and 6. FIG. 4 shows one embodiment of the fabric according to the present invention. The fabric 40 comprises a first regular or predetermined pattern of areas of low fiber density 41 and a second regular or predetermined pattern of areas of low fiber density 42, with the areas of low fiber density of the first pattern being several times larger than the areas of low fiber density in the second pattern. The first pattern is disposed in discontinuous portions of the fabric whereas the second pattern is disposed in continuous portions of the fabric. The first pattern of areas of low fiber density are defined by yarn-like bundles 43 of fiber segments, interconnected at junctures 44. Some of these yarn-like bundles viz. 4311, are heavier in weight than other of these yarn-like bundles 43b which aid in defining the first pattern. The second pattern of areas of low fiber density are also defined by yarn-like bundles of fiber segments 45 interconnected at junctures 46. Some of the areas of low fiber density in the second pattern are defined at least in part by the heavier yarn-like bundles 43a which aid in defining the first areas; however, in all instances, these heavier bundles define at least a portion of the perimeter of the areas of low fiber density in the first pattern.

The exact positioning of the heavier bundles in the fabric will depend to a large extent upon the amount of water or the amount of force utilized in producing the yarn-like bundles. The forces used along with the amount of fiber being moved will determine how far the heavier yarn-like bundles will be disposed from the larger areas of low fiber density in the final product. Also, in some modifications of the process, if the imperforate areas of the backing belt have a third dimension, i.e., raised out of the plane of the backing belt, the heavier bundles will tend to align themselves immediately adjacent the imperforate area and will not tend to be pushed away from the periphery of the imperforate area. This will result in a product wherein the heavier yarn-like bundles are adjacent the periphery of the larger areas of low fiber density.

Another factor which will determine the positioning of the heavier yarn-like bundles is the orientation of the fibers in the starting fibrous web. For example, if a highly oriented starting web is used, the heavier bundles will have a similar orientation and a portion of a heavier bundle will define only a portion of the periphery of a larger area of low fiber density. If an isoweb is used as the starting material and the necessary conditions described above are present, a heavier yarn-like bundle will define the entire periphery of a larger area of low fiber density. Such a fabric made from an isoweb is schematically depicted in FIG. 6. The fabric comprises a first predetermined pattern of areas of low fiber density 111 and a second predetermined pattern of areas of low fiber density 112 with the areas of low fiber density of the first pattern considerably larger than the areas of low fiber density in the second pattern. The first pattern of areas of low fiber density are defined by heavier yarn-like bundles 1 14 which extend substantially around the entire periphery of the area. The second pattern of areas of low fiber density are also defined by yarn-like bundles 115 interconnected at junctures 116.

FIG. 5 of the drawings shows yet another embodiment of the fabric of the present invention. The fabric 50 comprises a first pattern of large areas of low fiber density 5 1 and a second pattern of smaller areas of low fiber density 52. The areas of low fiber density in the first pattern are defined by yarn-like bundles of fiber segments 53 interconnected at junctures 54. The areas of low fiber density in the second pattern are defined by yarnlike bundles of fiber segments 55 which interconnect at junctures 56. In the areas of low fiber density in the second pattern, there are further yarn-like bundles 57 which extend across the areas of low fiber density of the second pattern. The yarn-like fiber bundles 57 interconnect with each other at substantially right angles.

In the schematic drawing, FIG. 7, there is depicted another embodiment of the fabric of the present invention. In this embodiment the first pattern of areas of low fiber density are substantially square in shape and are aligned in the longitudinal and transverse directions of the fabric 121. The second pattern of areas of low fiber density is comprised of a first subpattern of areas of low fiber density 122 which lie between adjacent pairs of the areas of low fiber density of the first pattern. The areas in the first subpattern are defined by yarn-like bundles 123 of fiber segments. There is also a second subpattern of areas of low fiber density #124 which lie between adjacent areas of low fiber density in the first pattern that are disposed diagonally. The areas of low fiber density in the second subpattern are defined by yarn-like bundles 125 of fiber segments connected at junctures 126.

In the photomicrograph of FIG. 8, there is shown a fabric 130 of the present invention. The fabric has a first pattern of areas of holes or of low fiber density I131 which are more or less oval in shape and are disposed in aligned rows as contrasted to the circular portions aligned in staggered rows as shown in 'FIG. 1. Lying between adjacent areas of low fiber density of the first pattern (both in the machine direction and perpendicular thereto) is a subpattern of areas of low fiber density 132 defined by yarn-like bundles 136, any four of the first subpattern of areas of low fiber density 132 surround a second subpattern of areas of low fiber density 134 in the 12, 3, 6 and 9 oclock positions. The areas of low fiber density in the second subpattern are defined by yamlike bundles i135 interconnected at junctures 136.

In FIG. 9 is shown a fabric similar to that shown in FIG. 8, except the fabric shown was photomicrographed from the opposite side. The fabric 140 in FIG. 9 comprises a first pattern of areas of low fiber density 141 which are more or less oval in configuration and are aligned longitudinally and transversely. Adjacent areas 141, both in the machine direction and perpendicular thereto, are connected by a first subpattern of areas of low fiber density 142 each such area being defined by yarn-like bundles 143. Any four of the first subpattern of areas of low fiber density 142 surround a second subpattern of areas of low fiber density 144 in the 12, 3, 6, and 9 oclock positions. The areas of low fiber density in the second subpattern are defined by yarn-like bundles 145 of fiber segments interconnected at junctures 146-.

The various patterns shown in FIGS. 1-9 have been predetermined, i.e., they are regular in appearance. The regularity of the pattern may vary over a wide range in order to obtain desired aesthetic appearances in the final fabric, for example, the lace-like appearance of the fabric 60 shown in FIG. 10. The pattern of the larger areas of low fiber density 61 are predetermined or regular and lie in discontinuous portions of the fabric and the predetermined or regular pattern of smaller areas of low fiber density 62 are in continuous portions of the fabric.

As previously mentioned, the relative size of the holes or other areas of low fiber density in the first and second patterns is important and may be varied over wide ranges. In the schematic drawing of FIG. 11, there is shown holes 150 in the first pattern which are four times larger than the holes 151 in the second pattern. The holes in the first pattern must be at least four times larger than the holes in the second pattern to produce the fabric of the present invention. The holes in the first pattern may be a few thousand or even ten thousand times larger than the holes in the second pattern. In FIG. 12, the holes 152 in the first pattern are approximately 100 times larger than the holes 153 in the second pattern. In accordance with the present invention, it is preferred that the holes in the first pattern be from about 10 to a hundred times larger than the holes in the second pattern. If holes 152, for example, are too large, the fabric has very poor stability and the holes will collapse when the fabric is handled and tension placed on the fabric, making further processing extremely diificult.

The size of the larger holes depends in part on the weight of the starting fibrous material. In general, the more fibers that have to be moved by the fluid forces, the more difficult it is to form a hole which is entirely free of fibers. Again, in general, the size and shape of the various holes in the fabric determines in a large measure the aesthetic characteristics of the final fabric.

The holes or other areas of low fiber density in the first pattern should have a largest dimension of at least two times the largest dimension of the holes or other areas of low fiber density in the second pattern. The holes in the first pattern may have a largest dimension which is as much as 50 or 100 times larger than the largest dimension of the holes in the second pattern. It is usually preferred that the largest dimension of the holes in the first pattern 10 be from about 3 to 10 times larger than the largest dimension of the holes in the second pattern.

DESCRIPTION OF MACHINE AND METHOD FOR MAKING FABRICS OF MY INVENTION Referring to FIG. 13 in the drawings, there is shown one form of apparatus for carrying out methods to produce products in accordance with the present invention. Full particulars of this apparatus except for the details of the novel backing or supporting member on which rearrangement of fibers takes place in accordance with the present invention including methods of mounting, rotation, etc., are fully described in US. Patent 2,862,251 issued Dec. 2, 1958 and are incorporated in the present appli cation by reference and thus need not be described in complete detail herein. In view of this reference, the apparatus of FIG. 13 will be described in general terms insofar as its essential elements are the same as in the patent just mentioned, and the novel element of this apparatus, i.e., the backing or supporting member, will be described in more detail.

The apparatus includes a rotatable perforated drum 70 suitably mounted on flanged guide wheels 72 and 73. The drum has apertures 74 uniformly spaced over its entire surface. The guide wheels are mounted for rotation on shafts 75 and 76. Inside the drum there is stationarily mounted along the full width of the drum, a manifold 77 to which a fluid is supplied through conduit 78. On one side of the manifold is a series of nozzles 79 for directing the fluid against the inside surface of the drum.

A novel backing or supporting member 80 is arranged to travel with rotatable drum 70 as will be described below. (The term backing member and support member are used interchangeably throughout this description.) Support member 80, as shown in FIGS. 14 and 140, has a continuous pattern of foraminous portions 100 and a discontinuous pattern of imperforate portions 101. In FIGS. 14 and 14a, the imperforate portions are round and arranged in a square pattern over the surface of the support member, the remainder of the member being foraminous. As already indicated above, the imperforate portions of the backing member may have any shape desired. They may also be arranger in any discontinuous pattern over the support member, i.e., they may be aligned longitudinally and/or transversely, staggered, etc.

The support member passes about drum 70 and separates from the drum at the guide roll 81 which rotates on a shaft 82. The support member passes downwardly around guide roll 83 rotating on shaft 84 and then rear- Wardly over a vertically adjustable tensioning and tracking guide roll 85 rotating on a shaft 86 and then around guide roll 87 on a shaft 88. The member passes upwardly and around guide roll 89 rotating on shaft 90 to be returned about the periphery of the drum.

The drum and supporting belt 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 nonwoven fabric having two or more patterns throughout its area. Tension on the support member 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 support member. 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.

Apertured drum 70 rotates in the direction of the arrow shown, and support member 80 moves in the same direction and at the same peripheral linear speed as the drum, 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 91 -to be rearranged is fed between the drum and support member at point A, passes through the 1 1 fiber rearranging zone where fluid rearranging forces are applied to it, and is removed in its new, rearranged form as nonwoven fabric 92 between the support member and apertured drum at point B.

As fibrous material 91 passes through the fiber rearranging zone, a liquid such as water is directed against the inner surfaces of rotating apertured drum 70 through nozzles 77 mounted inside the drum. The liquid passes through drum apertures 74 and through the fibrous web and thence through the backing means, thereby effecting rearrangement of the fibers of the web. Suction box 71 helps to remove water within the rearranged web 92 before it reaches takeoff point B.

The directions the streams of rearranging fluid projected through the apertures of the apertured 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 the apertures are determined by foraminous portions 100 and imperforate portions 101 of support memher or backing means 80, it follows that it is the patterns of these areas that at least in part determine the patterns of holes or other areas of low fiber density in the resulting web.

The portions of the rearranging fluid in the areas where support member 80 is formaminous pass directly through both the web and the support member. This direct type of flow through adjacent apertures of the drum 70 and then through foraminous portions 100 of backing means 80 produces counteracting components of force which act in the plane of the web until the fluid is able to pass out through the support member. These fluid forces work in conjunction with one another to rearrange fiber segments into interconnected bundles of fiber segments, packing the fiber segments into yarn-like bundles that lie between land areas of the drum 70 and foraminous portions 100 of backing means 80, as shown and described in detail in my U.S. Pat. 2,862,251.

The portions of the rearranging fluid in each area where backing means 80 is imperforate passes over these areas of the support member, and push fiber segments off the imperforate portions 101 to align the fiber segments substantially adjacent the periphery of these imperforate portions. In some instances, the fluid may push all fiber segments off the imperforate portions of the backing means, while in other instances some fiber segments are left to span those portions.

The weight of the starting fibrous web being processed and the configuration, size and spacing of the imperforate portions of the backing means will determine whether or not heavier yarn-like bundles are formed in the fabric of this invention. These same factors, along with the topography of the foraminous portions 100 of backing means 80, the fiber orientation in the starting fibrous web, and the magnitude of the fluid rearranging forces applied to the starting web will determine the disposition of any heavier yarn-like bundles that are formed.

FIG. gives an enlarged fragmentary diagrammatic plan view of the foraminous portion 80 of another backing means that can be used with the apparatus of FIG. 13. Foraminous portion 80 of the backing means for use in this invention is formed of coarse woven screen, preferably metal. In the embodiment shown, Wires 159 running vertically in FIG. 15 are straight, while wires 160 running horizontally in that figure weave alternately over and under wires 159. Protuberances 161 are present throughout foraminous portion 80 as the topmost part of each knee, of a given strand 160 of the screen that is formed as the strand weaves over and under the strands 159 that lie perpendicular to it.

As a given strand 160 slants downward to pass under a strand 159 perpendicular to it, it crosses two other strands 160 disposed on either side of it, as those strands slant upward to pass over the same perpendicular strand 12 that the given strand will pass under. Each series of such crossing points 162 forms a trough, such as trough 163 formed by crossing points 162 in FIGS. 15 and 16, that lies between adjacent protuberances 161..The effective shape of troughs 163 as can be best seen in FIG. 16 (which shows a cross section of element of which a plan view is given in FIG. 15), is substantially an inverted triangle.

A series of slightly deeper troughs 164 is formed between adjacent protuberances 161 but extending at right angles to troughs 163. As best seen in FIG. 17, the bottom of each trough 164 is formed by portions of straight strands 159, with successive protuberances 161 on each side of the trough forming the tops of the trough. As seen in FIG. 17, the effective shape of troughs 164 may be characterized as a shallow U-shape.

As shown in FIG. 15, a plurality of troughs 163 and a plurality of protuberances 161 alternate in one direction across the surface of foraminous portion 80 of the backing means. FIG. 15 also shows that a plurality of troughs 164 and a plurality of protuberances 161 alternate in a direction perpendicular to troughs 163. Hence a plurality of troughs and a plurality of protuberances alternate in both the longitudinal and transverse directions across the surface of foraminous portion 80 of the backing means.

Use in the method or apparatus described of a backing means having foraminous portions such as element 80 shown in FIGS. 15 through 17 produces the third pattern of areas of low fiber density described above. This pattern is disposed within the second pattern of areas of low fiber density corresponding to apertures 74 of forming means 70. The third pattern of areas of low fiber density is defined by yarn-like bundles of fiber segments that have been positioned in troughs 163 and 164 on the surface of foraminous portions 80 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 163 and 164, the vertical distance between the tops of protuberances 161 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 about five to about ten times, the average diameter of the fibers in the layer of fibrous starting material. For troughs 163, this distance is the vertical distance indicated in FIG. 16 by the pair of dashed lines that pass, respectively through the tops of protuberances 161 and the crossing points 162 that define troughs 163. The vertical distance from the bottom of each trough 164 to the tops of protuberances 161, on the other hand, is somewhat larger, being shown by FIGS. 16 and 17 to be equal to the diameter of a strand 160.

The relative position of a forming aperture 74 and protuberances 161 of foraminous portion 80 of the backing means in one formof this invention is shown in dashed lines in FIG. 15. As is seen, aperture 74, in both the longitudinal and transverse directions, has a width somewhat larger than two times the horizontal distance between the tops of immediately adjacent protuberances 161 and spans two such protuberances measured in both the longitudinal and transverse directions.

During use of this invention, apertured forming means 70 and the backing means of which element 80 is a part are spaced to provide a fiber rearranging zone.

Portions of the streams of rearranging fluid that pass through forming apertures 74 and the fibrous W61) pass directly through openings 165 between adjacent wires of woven screen 80. Other portions of the streams of rearranging fluid that have passed through apertures 74 strike the wires of woven screen 80, at protuberances 161 or at other portions of the wire, and are deflected sidewise before they pass out of the rearranging zone through openings 163.

The streams of rearranging fluid just described move some of the fiber segments that are in registry with apertures 74 and overlie foraminous portions 80 of the backing means into surrounding areas of the fibrous layer, positioning the fiber segments there in yarn-like bundles of closely associated and substantially parallel fiber segments, to define holes or other areas of low fiber density in a pattern corresponding to the pattern of apertures 74. This is referred to above as the second pattern of the nonwoven fabric made in accordance with this invention, since it is in addition to the pattern of larger holes or other areas of low fiber density that correspond to discontinuous imperforate portions 101 of backing means 80.

At the same time, the fluid rearranging forces move other fiber segments that are in registry with forming apertures 74 and overlie foraminous portions 80 into troughs 163 and 164, positioning those fiber segments there in yarn-like bundles of closely associated and substantially parallel fiber segments, to define a third pattern of holes or other areas of low fiber density disposed within the second pattern just described.

The pattern of foraminous and imperforate areas in the support member will determine the patterns of areas of lowfiber density in the resulting rearranged fibrous web. The directions the fluid take in and through the fibrous web determines the type of forces applied to the fibers and, in turn, the rearrangement of the fibers. These directions are determined by the foraminous and im- =perforate areas of the support member. The portion of the fluid in the areas where the support member is forminous passes both through the web and through the support member. This type of fiow causes counteracting components of force which act in the plane of the web until the fluid is able to pass out through the support member. These fluid forces work in conjunction with one another to rearrange fiber segments into interconnected bundles of fiber segments packing the fiber segments into yarn-like bundles. The portion of the fluid in the area where the support member is imperforate passes only over the support member and pushes fiber portions out of the imperforate areas and align the fiber portions substantially adjacent the periphery of the imperforate areas. In some instances, the fluid may push all fiber portions out of the imperforate areas while in other instances, some fiber portions are left in the imperforate area to span these areas.

The weight of the starting fibrous web being processed, the configuration and size of the irnperforate areas as well as the spacing of these areas have a bearing on the dimensions of the yarn-like bundles in the fabric of my invention. These same factors along with the topography of the support member, the fiber orientation in the starting fibrous web, and the magnitude of the fluid forces applied to the starting web will determine the disposition of the yarn-like bundles in the final fabric.

The fabric described in conjunction with the schematic drawing in FIG. may be produced by using a coarse woven wire screen as the foraminous portion of the support member with resulting protuberances and troughs, as described above.

The rearranged web or fabric of this invention may be treated with an adhesive, dye, or other impregnating, printing, or coating material in a conventional manner. For example, to strengthen the rearranged web, any suitable adhesive bonding materials or binders may be included in an aqueous or non-aqueous medium employed as the rearranging fluid. Or an adhesive binder may, if desired, be printed on the rearranged web to provide the necessary fabric strength. Thermoplastic binders may, if desired, be applied to the rearranged web prior, during or after rearrangement in powder or other form and then fused to bond the fibers.

The optimum binder content for a given fabric according to this invention depends upon a number of factors, including the nature of the binder material, the size and shape of the binder material and their ar- 14 rangement in the fabric, the nature and length of the fibers, total fiber weight, and the like. In some instances, because of the strength of the fibers used or the tightness of their interentanglement in the rearranged web or fabric, no binder at all need be employed to provide a usable fabric.-

Further details and descriptions of methods and apparatus which may be used to produce the novel nonwoven fabrics of the present invention are given in my commonly assigned patent applications entitled Method and Apparatus for Producing Nonwoven Fabrics Having a Plurality of Patterns (Ser. No. 22,299 filed Mar. 24, 1970 and now abandoned), Method and Apparatus for Producing Nonwoven Fabrics Having a Plurality of Patterns (Ser. No. 22,309 filed Mar. 24, 1970 and now abandoned) and Method and Apparatus for Producing Nonwoven Fabrics Having a Plurality of Patterns (Ser. No. 22,313 filed Mar. 24, 1970 and now abandoned) filed concurrently with the present patent application. It is to be noted that not all embodiments of the apparatus disclosed in the above-mentioned patent applications will necessarily produce the novel nonwoven fabrics of the present invention.

The following are illustrative examples of the methods for producing the patterned nonwoven fabrics of the present invention.

Example 1 In apparatus as illustrated in FIG. 13, a web 91 of loosely assembled fibers, such as may be obtained by carding, is fed between apertured forming means 70 and backing means 80. The web weight is about 450 grains per square yard, and its fiber orientation ratio approximately 7 to 1 in the direction of travel. The web contains viscose rayon fibers approximetly 1%," long, of 1 /2 denier. l

Apertured forming means 70 has about 165 substantially round holes per square inch, each approximately 0.045" in diameter, arranged in a diamond pattern over the forming means. Each aperture is spaced approximately 0.018 in the diagonal direction from the immediately adjacent aperture on the drum.

The foraminous portions of backing means are comprised of a woven nylon screen of approximately 28 x 34 mesh or substantially 952 opening per square inch.

Imperforate portions of the backing means 80 are smooth round metal members of a diameter of approximately A". They are distributed over the area of backing means 80 in a diamond pattern, with a space of approximately /a" from each portion to the nearest other portion in a diagonal direction. Central portions of the imperforate area rise 0.012" above the plane of the top surface of continuous foraminous portions of the backing means, and edge portions of the imperforate area rise about 0.010" above that plane.

Water is projected from nozzles 79 through apertures in the apertured forming means 70, and thence through fibrous web 91 and backing means 80.

After a given portion of fibrous web 91 passes through the rearranging zone, in which streams of water are directed against it as just described, the rotation (in the counterclockwise direction as seen in FIG. 1) of the sandwich comprised of apertured drum 70, the rearranged nonwoven fabric 92, and backing means 80 brings the rearranged fabric over vacuum drying means 71, which helps to remove the water remaining in the fabric. Fabric 92 is then carried forward to takeoff zone B where it leaves the apparatus.

With the conditions indicated, good fiber rearrangement and bundling are obtained, and an excellent nonwoven fabric such as shown in the photomicrograph of FIG. 1, which has a plurality of patterns alternating and extending throughout the fabric, is produced.

Nonwoven fabric 20 of FIG. 1 contains a first pattern of holes 21, each of which holes overlies a discon- 15 tinuous imperforate portion of backing means 80, and is defined by yarn-like bundles 23 of closely associated and substantially parallel fiber segments.

In addition, nonwoven fabric 20 contains a second pattern of areas of low fiber density 22, arranged in accordance with the pattern of arrangement of apertures in apertured forming means 70 that overlies foraminous portions of backing means 80.

Each of these areas 22 is defined by yarn-like bundles 25 of closely associated and substantially parallel fiber segments. Each hole 21 appears from FIG. 1 to be approximately 25 times the size of each area of low fiber density 22, or a little bit larger. This is consistent with the relative size of discontinuous imperforate portions of backing means 80 and apertures of apertured forming means 70 that are included in the apparatus with which the fabric of FIG. 1 was made. The round apertures of .the apertured forming means 70 have a diameter of about 0.045", which gives each of them an area of about 0.0064 square inch. The imperforate portions of the backing means have a diameter of about A", which gives each of them an area of about 0.197 square inch, or in other words, about 30 times the area of each aperture of the apertured forming means.

It is evident from FIG. 1 that during the production of the fabric there illustrated, imperforate portions of the backing means 80 underlay some, but not all, of the apertures in the apertured forming means. Each pair of immediately adjacent large holes or areas of low fiber density 21 is separated by at least one of the smaller holes or areas of low fiber density 22. To produce this result, the width of the interconnecting foraminous portions of backing means 80 (or, in other words, the closest diagonal spacing between imperforate portions of the backing means, which is about A3" or 0.125") is equal to about two times the distance between the centers of a pair of immediately adjacent apertures of forming mean 70 (or, in other words, two times 0.063).

Example 2 FIG. 4 is a schematic drawing of another nonwoven fabric of the present invention, made from starting material similar to that used in Example 1 and by use of apparatus similar to that described in that example. The fabric of FIG. 4 is generally similar to the fabric of Example 1, with the exception that the larger holes are arranged in a square pattern instead of a diamond pattern throughout the fabric.

Nonwoven fabric 40 has a first pattern of larger holes 41 that corresponds to the pattern of discontinuous imperforate portions 101 of backing means 80. Each larger hole 41 is defined by a plurality of yarn-like bundles 43 of closely associated and substantially parallel fiber segments. The fabric also contains a second pattern of smaller areas of low fiber density 42 in locations where apertures of apertured forming means 70 coincide with continuous foraminous portions 100 of backing means 80. Holes 42 are likewise defined by yarn like bundles 45 of closely associated and substantially parallel fiber segments.

In nonwoven fabric 40, heavier yarn-like bundles 43a of closely associated and substantially parallel fiber segments extend generally in the machine direction of the starting fibrous material. These heavier yarn-like bundles 43a assist in defining areas of low fiber density 21, as well as areas of low fiber density 22.

The weight of the starting fibrous web being processed and the configuration, size and spacing of the imperforate portions of the backing means will determine whether or not heavier yarn-like bundles are formed in the fabric produced by use of the method or apparatus described. These same factors, along with the topography of the foraminous portions 100 of backing means 80, the fiber orientation in the starting fibrous web, and the magnitude of the fluid rearranging forces applied to the starting web will determine the disposition of any heavier yarn-like bundles that are formed.

The nonwoven fabric of this example has excellent properties. Heavier yarn-like bundles are visible under careful visual examination of the fabric, and add to the aesthetic appearance of the product.

Example 3 In apparatus as illustrated in FIG. 13, a web 91 of loosely assembled fibers of the type commonly called an isotropic web is fed between apertured forming means 70 and backing means 80. The web weight is about 350- grains per square yard, and web strength is measured at substantially the same magnitude in every direction throughout the web. The web contains viscose rayon fibers approximately 1%! long of 1 /2 denier.

The apertured forming means 70 used in this example is the same as that employed in Example 1.

Backing means is the same as the backing means employed in Example 1, except that discontinuous imperforate portions 101 are arranged in a square pattern over the surface of backing means 80, with a space of approximately /s" between each portion 101 and the nearest other such portion in both the longitudinal and transverse directions.

Using the same general mode of operation as in Example 1, an excellent nonwoven fabric such as is shown in the photomicrograph of FIG. 2 is obtained.

Nonwoven fabric 30 of FIG. 2 contains a first pattern of holes 31, each of which is defined by yarn-like bundles 33 of closely associated and substantially parallel fiber segments. Each of those holes is formed in a portion of the fibrous starting material that overlies a discontinuous imperforate portion 101 of backing means 80.

In addition, nonwoven fabric 30 contains a second pattern of areas of low fiber density 32, arranged in accordance with the pattern of arrangement of apertures in apertured forming means 70 that overlie foraminous p01- tions of backing means 80. Each of these areas 32 is defined by yarn-like bundles 35 of closely associated and substantially parallel fiber segments.

Each area 31 appears from FIG. 2 to be approximately 25 times the size of each area of low fiber density 32, or a little bit larger. This is consistent with the relative size of imperforate portions 101 and apertures in the apparatus used to make the nonwoven fabric of FIG. 2, since the former have an area about 30 times as large as the area of the latter.

It is evident from FIG. 2 that during the production of the fabric there illustrated, imperforate portions 101 of backing means 80 underlie some, but not all, of the apertures in the apertured forming means. Each pair of immediately adjacent large areas of low fiber density 31 spans at least one of the smaller areas of low fiber density. To produce this result, the width of the interconnecting foraminous portions 100 of backing means 80 at their narrowest portion is equal to about two times the distance between the centers of a pair of immediately adjacent apertures of forming means 70, just as was true in Example 1 above.

A cross sectional view of the fabric of FIG. 2 is given in FIG. 3, taken along a line similar to that shown as line 33 in FIG. 2, and with an enlargement twice the enlargement in that figure. Yarn-like bundles of fiber segments 33 define the larger areas of low fiber density. Smaller areas of low fiber density 32 are seen in cross section, defined by yarn-like bundles of fiber segments 35.

Example 4 Apparatus, starting material and operation conditions as described in Example 2 are used in this example, except that the foraminous portions of the backing means 80 are similar to element 80 of FIGS. 15 through 17. These foraminous portions comprise a woven nylon screen of approximately 14 x 18 mesh or substantially 252 holes 17 per square inch. The tops of protuberances 161 are about 0.005" above the bottoms of the immediately adjacent troughs 163, or in other words a vertical distance a little more than three times the 0.0015" diameter of fibers of 1% denier of the starting material used here.

The horizontal distance between the tops of immediately adjacent protuberances 161 is about 0.055" in one direction and about 0.070" in the other, or in other words, about 37 and about 47 times, respectively, the 0.0015" diameter of the fibers of the starting material. Each aperture 74 of apertured forming means 70 is about 0.045" in diameter, or the same general magnitude as the horizontal distance between the tops of immediately adjacent protuberances 161.

FIG. 5 gives a schematic drawing of a portion of the resulting nonwoven fabric.

Nonwoven fabric 50 has a first pattern of holes 51 that corresponds to the pattern of discontinuous imperforate portions 101 of backing means 80. Each larger area 51 is defined by a plurality of yarn-like bundles 53 of closely associated and substantially parallel fiber segments.

The fabric also contains a second pattern of smaller holes or areas of low fiber density 52 in locations where apertures 74 of apertured forming means 70 coincide with continuous foraminous portions 100 of backing means 80. Areas 52 are likewise defined by yarn-like bundles 55 of closely associated and substantially parallel fiber segments.

In nonwoven fabric 50, heavier yarn-like bundles of closely associated and substantially parallel fiber segments extend generally in the machine direction of the starting fibrous material. These heavier yarn-like bundles assist in defining areas of low fiber density 51, as well as areas of low fiber density 52.

Still a third pattern of holes or other areas of low fiber density lies within the pattern of smaller areas of low fiber density 52. The third pattern is defined by yarn-like bundles 57 of closely associated and substantially parallel fiber segments positioned in troughs 163 of foraminous portions 80 of the backing means shown in FIGS. 15 through 17.

The nonwoven fabric of this example has excellent properties, and the three patterns of areas of low fiber density contribute substantially to the aesthetic appearance of the product.

Example 5 In apparatus as illustrated in FIG. 13, a web 91 of loosely assembled (fibers, such as may be obtained by carding, is fed between apertured forming means 70 and backing means 80. The web weight is about 320 grains per square yard, and its fiber orientation ratio approximately 7 to 1 in the direction of travel. The web contains viscose rayon fibers approximately 1 1 long, of 1 /2 denier.

Apertured forming means 70 has about 165 substantially round holes per square inch, each approximately 0.045" in diameter or about 30 times the average diameter of the fibers of the fibrous starting material. The holes are arranged in a diamond pattern over the forming means. Each aperture 74 is spaced approximately .040" in the diagonal direction from the immediately adjacent aperture on the drum.

The backing means used in this example has discontinuous foraminous portions comprised of a woven fiber glass screen of approximately 14 x 18 mesh or substantially 252 openings per square inch. Each foraminous portion is square in shape, approximately A" on each side, and is spaced from the immediately adjacent similar foraminous portions by approximately in each direction.

The portions separating the foraminous portions are continuous and imperforate and comprise a low density polyethylene mesh or grid. The width of each imperforate portion between foraminous portions is approximately as mentioned above or about 0.074", which is about two times the diameter of each aperture 74 of the apertured forming means 70.

With the conditions indicated, good fiber rearrangement and bundling are obtained, and an excellent nonwoven fabric such as shown in the photomicrograph of FIG. 8 which has a plurality of patterns that alternate and extend throughout the fabric, is produced.

Nonwoven fabric of FIG. 8 contains a first pattern of areas of low fiber density 131. Lying between adjacent areas of low fiber density 131 is a subpattern of areas of low fiber density 132.. This subpattern surrounds another subpattern of areas of low fiber density 134 at the 12, 3, 6, and 9 oclock positions. The areas of low fiber density 134 correspond to the position where the apertures 74 in the forming means and backing member are in registry. The subpattern of areas 132 surrounding the areas of low fiber density 134 correspond to the positions where the aperture 74 in the forming means and the imperforate portions of the backing member between the foraminous portions are in registry. The first pattern of areas of low fiber density 131 correspond to the crossing points of the imperforate portions of the backing member.

FIG. 9 is a photomicrograph of the nonwoven fabric of FIG. 12 taken from the opposite side of the fabric, showing a different but similar portion thereof.

Example 6 In FIG. 18 there is shown a photomicrograph of another fabric of the present invention. The starting material used was a card web of viscose rayon fibers, 1 /2" staple length and 1 /2 denier. The card web used weighed about 500 grains per square yard.

The card web is placed on a backing member comprising a coarse woven wire screen similar to that described in conjunction with FIGS. 15 through 17. The screen had 8 wires per inch running in both directions with each wire having a diameter of 0.023 inch. The depth of the troughs produced in such a coarse woven wire screen is about 0.045 to 0.050 inch. On the surface of the woven screen there is adhered a pattern of discontinuous imperforate areas. These areas are metal discs and are arranged in a diamond pattern with each area being substantially circular in shape and having a diameter of about inch. The areas are spaced from each other in diagonal directions about A inch. The imperforate areas extend above the surface of the wire screen about /3 inch and the card web is placed on top of these imperforate areas.

Water is sprayed through conventional solid cone nozzles onto the card web while it is lying on the backing means. The water pressure used is about 100 pounds per square inch and the nozzles deliver about 1.3 gallons of water per minute. The entire web is covered by the water spray from these nozzles.

With the conditions given above, good fiber rearrangement and bundling are obtained, and an excellent nonwoven fabric such as shown in FIG. 18, which has a plurality of patterns that alternate and extend throughout the fabric is produced.

Nonwoven fabric of FIG. 18 contains a first pattern of areas of low fiber density 181 with each area of low fiber density being defined by yarn-like bundles 182 of fiber segments. These areas of low fiber density 181 are located in discontinuous portions of the fabric. The fabric 180 also has a second pattern of areas of low fiber density 183 located in continuous portions of the fabric. The first pattern of areas of low fiber density 181 correspond to the discontinuous imperforate portions of the backing member described above while the second pattern of areas of low fiber density 183 correspond to the highest points in the coarse woven wire screen.

The nonwoven fabric of this example has excellent properties and considerable aesthetic appeal.

[Having now described the invention in detail, and exemplified the manner in which it may be carried into practice, it will be readily apparent to those skilled in the art that innumerable variations and modifications may be made without departing from its spirit and scope.

I claim:

1. A nonwoven fabric with a plurality of patterns of areas of low fiber density, each of which extends throughout said fabric, which comprises: a first regular pattern of areas of low fiber density, said areas being located in first discontinuous portions of the fabric, each of said areas of low fiber density being defined by a plurality of yarn-like bundles of fiber segments, 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 in the lay of the fabric, and a second regular pattern of areas of low fiber density, said areas being located in second continuous portions of the fabric lying between each pair of adjacent areas of low fiber density in said first pattern, each area of low fiber density in said first pattern being at least about four times larger than each area of low fiber density in said second pattern, each of said areas of low fiber density in said second pattern being defined at least in part by other yarn-like bundles of fiber segments formed and interconnected in the same manner as said first mentioned yarn-like bundles of fiber segments, with some of said areas in said second pattern being defined in part by said first mentioned yarnlike' bundles of fiber segments.

, 2. The nonwoven fabric of claim 1 in which the maximum dimension of each area of low fiber density in said first pattern is no more than about four times the minimum dimension of said area.

3. The nonwoven fabric of claim 1 in which each area of low fiber density in said first pattern is from about to 100 times larger than each area of low fiber density in said second pattern.

4. The nonwoven fabric of claim 1 in which the maximum dimension of each area of low fiber density in said first pattern is not more than about one-and-a-half the minimum dimension of said area.

5. The nonwoven fabric of claim 1, in which the areas of low fiber density in said first pattern are apertures substantially free of fibers.

6. The nonwoven fabric of claim 1 in which the areas of low fiber density in said second pattern are apertures substantially free of fibers.

7. The nonwoven fabric of claim 1, in which some of said yarn-like bundles of fiber segments are substantially heavier in weight than other such bundles of fiber segments.

8. The nonwoven fabric of claim 7 in which said heavier yarn-like bundles of fiber segments define at least a pordensity in said first pattern.

9. The nonwoven 'fabric of claim 7' in which said heavier yarn-like bundles of fiber segments extend generally in the direction of orientation of the fibers in said nonwoven fabric and lie adjacent said areas of low fiber density in said first pattern.

10. The nonwoven fabric of claim 9 in which said heavier yarn-like bundles of fiber segments lie immediately adjacent at least some of said areas of low fiber density in said first pattern.

11. The nonwoven fabric of claim 10 in which each of said heavier yarn-like bundles of fiber segments lies immediately adjacent a portion of said areas of low fiber density in said first pattern.

12. The nonwoven fabric of claim 7 in which at least some of said areas of low fiber density in said first pattern are entirely defined by said heavier yarn-like bundles of fiber segments. Y

13. The nonwoven fabric of claim 12 in which all of said areas of low fiber density in said first pattern are'entirely defined by said heavier yarn-like bundles of fiber segments.

14. The nonwoven fabric of claim 1, in which yarnlike bundles of fiber segments extend across areas of low fiber density in said second continuous portions of the fabric.

15. The nonwoven fabric of claim 14 in which said yarn-like bundles of fiber segments that extend across areas of low fiber density in said second portions of the fabric are interconnected in the manner aforesaid with other such bundles, said interconnection between yarn-like bundles being substantially at right angles.

16. The nonwoven fabric of claim 1 in which said first pattern of areas of low fiber density extend longitudinally and transversely throughout the fabric and in which said second pattern of areas of low fiber density is comprised of a first subpattern of areas of low fiber density which lie between each pair of adjacent areas of low fiber density in said first pattern, any four of said first subpatterns of areas surrounding a second subpattern of areas of low fiber density.

References Cited UNITED STATES PATENTS 3,485,706 12/1969 Evans 161-169 X 3,081,515 3/1963 Griswold et a1. 2878 3,033,721 5/1962 Kalwaites 161-150 3,486,168 12/ 1969 Evans et al. 161169 2,862,251 12/1958 Kalwaites 19-161 3,353,225 11/1967 Dodson et a1 19-16l 3,403,862 10/1968 Dworjanyn 239-566 3,434,168 3/1969 Summers 2872.2 3,485,708 12/1969 Ballou et a1. 161-72 3,494,821 2/1970 Evans 16l-l69 3,498,874 3/1970 Evans et a1. 161l69 X ROBERT F. BURNETT, Primary Examiner R. L. MAY, Assistant Examiner US Cl. X.R.

. mg? UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 681,182 Dated Aug. 1, 1972 l v t fl Frank Kalwaites It is certified. that error appears in the above-identified patent and that said Letters Patent are hereby, corrected as shown below:

. 1 I In Column 2, line 68, "subtsancial" should read-- substantial---. 1

In Column 3, line 37, "interconect" should read-- interconneet-.

In Column t, line 51, "small" should readsmaller-" In Column L, line 72, "back" should read backing--.

In Column 5, line 59, "top" should read" tops I In Column 6, line 32 delete "and" In Column 10, line 443, "arranger" should readarranged--.

In Column I L, line 35, "approximebly" should read-- approximately In Column 15, line 38, "mean" should read means In Column 20 References cited, line 51, "3, -l3 hl68" should a read 3,43%188 Signed and sealed this 17th day of April 1973.

(SEAL) Attest':

EDWARD M.FLETCHER,JR.'. ROBERTA GOTTSCHALK Attesting Officer Commissioner of Patents

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