US3800364A

US3800364A - Apparatus (discontinuous imperforate portions on backing means of closed sandwich)

Info

Publication number: US3800364A
Application number: US00225333A
Authority: US
Inventors: F Kalwaites
Original assignee: Johnson and Johnson
Current assignee: Johnson and Johnson
Priority date: 1970-03-24
Filing date: 1972-02-10
Publication date: 1974-04-02
Anticipated expiration: 1991-04-02

Abstract

An apparatus for producing, from a layer of fibrous material such as a fibrous web, nonwoven fabrics that contain apertures or holes, or other areas of low fiber density, and have a plurality of patterns that alternate and extend throughout the fabric. One form of the method includes the steps of positioning the starting web between apertured forming means and a backing means that is foraminous except for a discontinuous pattern of imperforate portions, then directing fluid rearranging forces through the apertures of the forming means against the fibers of the starting web, causing some of the fluid streams to strike the imperforate portions of the backing means and all of the fluid streams ultimately to pass through the foraminous portions of the backing means. The discontinuous imperforate portions of the backing means underlie the entire area of some but not all the apertures of the apertured forming means. Each of the discontinuous imperforate portions preferably has an area at least about four times the area of an aperture of the forming means. The imperforate portions of the backing means may rise above the foraminous portions. The resulting fabric consists of fibers that have been rearranged to provide a first pattern of holes or other areas of low fiber density corresponding to the imperforate portions of the backing means and a second pattern corresponding to the apertures of the apertured forming means that overlie the foraminous portions of the backing means. When a plurality of protuberances and troughs alternate across the surface of the foraminous portions of the backing means, the fluid rearranging forces of this method and apparatus rearrange the fibers of the fibrous starting material to produce a third pattern of holes or other areas of low fiber density within the second pattern already described.

Description

United States Patent [:91

Kalwaites Apr. 2, 1974 APPARATUS (DISCONTINUOUS IMPERFORATE PORTIONS ON BACKING MEANS OF CLOSED SANDWICH) Frank Kalwaites, Gladstone, NJ.

[73] Assignee: Johnson & Johnson, New

Brunswick, NJ.

[22] Filed: Feb. 10, 1972 [21] Appl. No.: 225,333

Related [1.8. Application Data [63] Continuation-impart of Ser. No. 22,299, March 24,

1970, abandoned.

[75] Inventor:

7/1963 Great Britain 28/72 NW Primary ExaminerDorsey Newton [57] ABSTRACT An apparatus for producing, from a layer of fibrous material such as a fibrous web, nonwoven fabrics that contain apertures or holes, or other areas of low fiber density, and have a plurality of patterns that alternate and extend throughout the fabric. One form of the method includes the steps of positioning the starting web between apertured forming means and a backing means that is foraminous except for a discontinuous pattern of imperforate portions, then directing fluid rearranging forces through the apertures of the forming means against the fibers of the starting web, causing some of the fluid streams to strike the imperforate portions of the backing means and all of the fluid streams ultimately to pass through the foraminous portions of the backing means. The discontinuous imperforate portions of the backing means underlie the entire area of some but not all the apertures of the apertured forming means. Each of the discontinuous imperforate portions preferably has an area at least about four times the area of an aperture of the forming means. The imperforate portions of the backing means may rise above the foraminous portions. The resulting fabric consists of fibers that have been rearranged to' provide a first pattern of holes or other areas of low fiber density corresponding to the imperforate portions of the backing means and a second pattern corresponding to the apertures of the apertured forming means that overlie the foraminous portions of the backing means. When a plurality of protuberances and troughs alternate across the surface of the foraminous portions of the backing means, the fluid rearranging forces of this method and apparatus rearrange the fibers of the fibrous starting material to produce a third pattern of holes or other areas of low fiber density within the second pattern already described.

4 Claims, 12 Drawing Figures PATENTEBAPR 21914 $800,364

SHEEI 1 OF 4 50 INVENTORJ fiTQAA A 4201 4/75 5 ATTORNEY.

PAIENTEDAPR 2 I974 I 3.800.364

sum 3 BF 4 /Z/ INVENTOR.

f/eww flz IVA/7'55 BY I A TTORNEY This is a continuation-in-part application of my co-' pending application Ser. No. 22,299, filed Mar. 24, 1970 now abandoned.

This invention relates to a method and apparatus for the production of nonwoven fabrics, and more particularly to a method and apparatus for the production of nonwoven fabrics from a layer of fibrous material such as a fibrous web, in which the individual fiber elements are capableof movement under the influence of applied fluid forces, to form a fabric that contains rearranged fibers defining a plurality of patterns of apertures or holes, or other areas of low fiber density, that alternate and extend throughout the fabric. Some of the rearranged fibers in the fabric lie in yarn-like bundles of closely associated and substantially parallel fiber segments, and these bundles help to define the areas of low fiber density inthe fabric.

BACKGROUND OF THE INVENTION Various methods and apparatus for manufacturing apertured nonwoven, fabrics involving the rearrangement of fibers in a starting layer of fibrous material have been known for a number of years. Some of these methods and apparatus for the manufacture of such fabrics are shown and described in U.S. Pat. No. 2,862,251, which discloses the basic method and apparatus of which the present invention is a specific form, and in U.S. Pat. Nos. 3,081,500 and 3,025,585.

The nonwoven fabrics made by the methods and apparatus disclosed in those patents contain apertures or holes, or other areas of low fiber density, often outlined by interconnected yarn-like bundles of closely associated and substantially parallel fiber segments. (The term areas of low fiber density" is used in this specification and claims to include both (I) areas in which relatively few fibers are found in comparison to the rest of the fabric, and (2) apertures (holes) that are substantially or entirely free of fibers.)

One of the specific methods for producing rearranged nonwoven fabrics that is disclosed in U.S. Pat. No. 2,862,251 is to support a loose fibrous web or layer between an apertured forming member and a foraminous backing member, and then direct streams of rearranging fluid through the apertures of the former member in order to apply spaced sets of opposing fluid forces to the fibers of the layer. The spaced streams of fluid pass through the fibrous layer and over and through the backing member, to pack groups of fiber segments into closer proximity and substantial parallelism in interconnected yarn-like bundles of fiber segments that define holes or other areas of low fiber density corresponding to the pattern of the apertures in the apertured forming means.

The fluid forces in the specific method described are 'usually applied over the entire surface of the loose fibrous web or layer and the permeable backing member on which it is supported, to produce fiber bundles uniformly distributed over the entire resulting fabric. In some instances, however, patterns can be made in the fabric by not applying fluidforces to predetermined areas of the fibrous layer, thereby preventing any fiber rearrangement from taking place in those areas.

In any event, in any area in which rearrangement is to be produced by the specific method referred to, the backing or support member is uniformly permeable throughout that area in order to provide a direct and unimpeded route by which the streams of rearranging fluid can be quickly carried away from the fiber rearranging zone between the backing member and apertured forming member. Every effort is made to avoid flooding" of the fibrous starting layer by accumulation of excess fluid in the area where rearrangement is taking place, and one of the means of avoiding such flooding is to provide a direct, rapid, and effective escape route for the streams of rearranging fluid after they have passed through the fibrous layer.

SUMMARY OF INVENTION I have now discovered that, unexpectedly, one can block off substantial portions of the otherwise permeable backing or support member in the specific method just described, to interrupt and impede the direct flow of rearranging fluid through the backing member, and still not impede satisfactory rearrangement of the fibers of the fibrous starting material into a rearranged nonwoven fabric having well defined apertures or other areas of low fiber density.

In the method of this invention, the starting material is a layer of fibrous material whose individual fibers are in mechanical engagement with one another but are capable of movement under applied fluid forces. The layerof fibrous starting material is supported in a fiber rearranging zone in which fiber movement in directions parallel to the plane of the fibrous material is permitted in response to applied fluid forces, and streams of rearranging fluid, preferably water, are projected into the fibrous layer at entry zones spaced from each other adjacent one surface of said layer, at the entry side of the rearranging zone. 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 fiber 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 barrier zones spaced from each other and lying directly opposite the entire area of some but not all of the above mentioned entry zones, adjacent the opposite surface of the fibrous layer, at the exit side of the rearranging zone. At the same time, those portions of fluid are deflected sidewise towards the other portions of the rearranging fluid and are actively mingled with the latter. All the portions of intermingled rearranging fluid are then passed out of the rearranging zone through exits lying between the barrier zones on the exit side of the rearranging zone In one form of the method and apparatus of this invention, the fibrous starting layer is supported on 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 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 penneable to the fluid streams used in fluid rearrangement, and these continuous foraminous portions of the backing means lie between and interconnect 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 discontinuous imperforate portions of the backing means used in this form of the invention underlie the entire area of some but not all of the apertures of the apertured forming means. Each such imperforate portion has an area that is preferably at least about four times as large as the area of an aperture of the apertured forming means, and blocks the flow of rearranging fluid through that area of the backing means as the fluid seeks to exit from the layer of fibrous starting material. Nevertheless, good fiber rearrangement into yarn-like bundles is still achieved.

The fibrous starting material used with the method and apparatus of this invention is comprised of closely intertwined and interentangled fibers arranged (depending on the degree of fiber orientation in the layer) in a more or less helter-skelter fashion. When streams of rearranging fluid are projected through the apertures of the apertured forming means against such a fibrous material where it lies above the imperforate portions of the backing means, one would expect that the streams would simply mat the interentangled fibers down against the imperforate portions of the backing means, with no fiber rearrangement produced in those areas at all. Or one might expect that the streams of fluid would subject the fibers to such turbulence as those streams struck the imperforate portions of the backing means that the fibers located there would simply swirl around and become still more closely intertwined in a helter-skelter arrangement, throughout the area lying above those imperforate portions, than they had been in the fibrous starting material.

Either of these two effects would be expected to be even more pronounced when, as is the case with some forms of the present invention, the discontinuous imperforate portions of the backing means have dimensions such that each portion underlies the entire area of each of a plurality of the apertures in the apertured forming means, for in that situation the streams of rearranging fluid would strike an even greater obstacle to passage away from the rearranging zone between the backing means and apertured forming means. In addition, in a case such as just described, in which a given discontinuous imperforate portion of the backing means spans a plurality of apertures in the forming means lying above it, one might expect that fiber segments would tend to be trapped by a set of opposed rearranging forces applied by fluid streams. passing through immediately adjacent apertures and deflected, in part at least, towards each other as they strike the imperforate portion of the backing means in those areas ofthe backing means lying beneath the land areas of the apertured forming means and over imperforate portions of the backing means, and would thus be held there against further lateral movement.

Still another factor that would be expected to interfere with the orderly and controlled fiber rearrangement necessary to produce a nonwoven fabric having a plurality of predetermined patterns of holes, or other areas of low fiber density, is the marked imbalance in the magnitude of the fluid rearranging forces that produce such areas when, as in a preferred form of the present invention, one of the areas is four times as large as the other. Since satisfactory rearrangement of fibers into yarn-like bundles of closely associated and subflow of fluid rearranging streams away from the rearstantially parallel fiber segments requires the balanced application of opposing fluid forces, such a great imbalance of rearranging forces would be expected to have a disruptive effect and make it impossible to achieve good fiber rearrangement.

The specific minimum size ratio of 4 to 1 between the areas of low fiber density in different patterns contained in fabrics produced by the preferred method or apparatus of this invention just mentioned would also be expected to present a serious difficulty in connection with removal of rearranging fluid from the fiber rearranging zone, for this size differential multiplies by four times the quantity of fluid that must be disposed of from the area overlying a single discontinuous imperforate area of the backing means as compared to the area of an aperture of the apertured forming means, while ordinarily it provides an increase of only about two times in the comparative perimeters of the two areas.

Surprisingly, it has been found that obstructing the ranging zone in the method and appartus of this invention by providing discontinuous imperforate portions of considerable size in the backing means does not have any of the undesirable results described. On the contrary, the blocking of the path of the fluid rearranging streams actually improves the bundling effect in some of the rearranged nonwoven fabrics produced by the method and apparatus of this invention. Specifically, when a discontinuous imperforate portion is provided in the backing means beneath the entire area of an aperture of the apertured forming means, it has been found that the fiber segments moved into yarn-like bundles in surrounding areas are packed even more tightly than without such an obstruction to the passage of fluid. In addition, the practice of this invention unexpectedly produces nonwoven fabrics having a plurality of predetermined patterns of areas of low fiber density alternating and extending throughout the fiber and defined by yarn-like bundles of closely associated and substantially parallel fiber segments.

The first pattern of holes or other areas of low fiber density occurs in those areas of the fabric that overlie the discontinuous imperforate portions of the backing means. This first pattern is produced by moving fiber segments that are in registry with the imperforate portions of the backing means into surrounding areas of the fibrous layer, to position them there in yarn-like bundles of closely associated and substantially parallel fiber segments that define the holes or other areas of low fiber density of this pattern.

At the same time, the fluid rearranging forces bring about bundling in the usual manner of fiber segments that are in registry with apertures of the apertured forming means and also overlie foraminous portions of the backing means. This produces yarn-like bundles of fiber segments under the adjacent land areas of the apertured forming means, to define in the resulting nonwoven fabric a second pattern of holes or other areas of low fiber density arranged in accordance with the pattern of the apertures in the apertured forming means below which the backing means is foraminous.

An interesting result is achieved when each discontinuous imperforate portion of the backing means underlies the entire area of each of a plurality of apertures in the apertured forming means, and the width of the interconnecting foraminous portion lying between immediately adjacent imperforateportions of the backing means is equal to at least about two times the distance between the centers of a pair of immediately adjacent apertures of the apertured forming means. As a result, there is in the apertured forming means a continuous band of apertures at least one aperture in width that has no imperforate portion of the backing means lying beneath it. This produces a fabric in which there is at least one band of smaller areas of low fiber density of the second pattern that runs between each pair of the larger areas of low fiber density that comprise the first pattern.

Still another interesting result is obtained when each of the foraminous portions of the backing means has a plurality of protuberances and troughs alternating acrossits surface in both the longitudinal and transverse directions. The resulting fabric displays three patterns extending throughout the fabric. The first of these is a pattern of holesor other areas of low fiber density corresponding to the pattern of the discontinuous imperforate portions of the backing means. The second pattern is apattern of holes or other areas of low fiber density corresponding to the pattern of apertures of the apertured forming means that overlie foraminous portions of the backing means. The third pattern of holes or other areas of low fiber density is disposed within the second pattern, being defined by yam-like bundles of fiber segments that have been positioned by use of this invention in thetroughs onthe surface of the foraminous portions of the backing means.

In every case, the streams of rearranging fluid applied in the use of the method and apparatus of this invention pass through the layer of fibrous starting material after they are directed through the apertures of the forming means, and some of the streams strike the imperforate portions of the backing means, or any protuberances present on the backing means, and are deflected in sidewise directions. From there, these streams of fluid, and all other streams of rearranging fluid that have not been deflected, are consolidated into streams of fluid that pass through and beyond the foraminous portions of the backing means, and thus away from the fiber rearranging zone.

7 FURTHER DESCRIPTION OF INVENTION The basic method and apparatus 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 feature peculiar to the methodand apparatus of the present invention, which is the provision of barrier zones to block and deflect portions of the streams of rearranging fluid, as by blocking portions of considerable size of the backing means on which the layer of fibrous starting material is supported, is described in detail in this applicationl Starting Material The starting material used with the method or apparatus of this invention may be any of the standard fibrous webs such as oriented card webs, isowebs, airlaid webs, or webs formed by liquid deposition. The webs may be formed in a single layer, orby 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. v

To produce a fabric having the characteristic hand and drape of a textile fabric, the layer of starting material used with the method or apparatus of this invention may comprise natural fibers such s 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 A inch to about 2 to 2 k inches. Satisfactory products may be produced in accordance with this invention from starting webs weighing between grains per square yard to 2000 grains per square yard or higher.

Apertured Forming Means In one form of the method of this invention, and in the apparatus .of this invention, the fluid entry zones into the fiber rearranging zone are. defined by an apertured forming means.

The apertured forming means used with this invention is solid throughout its area except for the forming apertures disposed longitudinally and transversely across the member. The forming apertures may have any desired shape, i.e., round, square, diamond, oblong, free form, etc.

The forming apertures are substantially larger in area than the foramina in the foraminous portions of the backing means. The width of each forming aperture at its narrowest part is for improved visual resolution of the pattern of areas of low fiber density equal to at least about ten times, and preferably twenty times, the average diameter of the fibers of the fibrous starting material.

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 yam-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, in one form of this invention the fibrous starting layer is supported on backing means having imperforate portions arranged in a discontinuous pattern to provide barrier zones against the passage of fluid out of the fiber rearranging zone, 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 the method and apparatus of this invention with openings in the foraminous portions of the backing means from about 900 openings per square inch to about 50,000

openings per square inchor 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.

For improved results, each discontinuous portion of the backing means should have an area of at least about four times and preferably from about 10 times to about 100 times, as large as the area of an aperture of the apertured forming means so that each imperforate portion will underlie at least 4 and preferably 10 to 100 of the apertures. 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, the area of each discontinuous imperforate portion of the backing means should not be more than 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 that corresponds to the discontinuous portion of the backing means, with consequent obliteration of the smaller 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 each discontinuous imperforate portion is no greater than about four times its minimum dimension, and still further improvement is produced if the maximum dimension is no more than about one-and-a-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 Vs to A inch maximum dimension, when fibers having an inch-and-a-half staple length are employed. If one dimension of a discontinuous portion of the backing 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 off 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 off 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 F1- bers 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 fluid 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 I /64 inch above the plane of that surface, and preferably by about l/32 to l/l 6 inch. The height of the discontinuous imperforate portions should generally be no more than about A inch, 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 portions 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. How ever, 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, free form, etc.

The discontinuous imperforate portions of the backing means 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. To improve fiber rearrangement, the central portion of the top of each discontinuous imperforate portion may rise higher than the edge portions.

If an additional pattern of holes or other areas of low fiber density is desired in the fabric produced by use of the backing means already described in the method or apparatus of this invention, the continuous foraminous portions of the backing means are provided with a plurality of protuberances and troughs alternating across their surface in both the longitudinal and transverse directions. For improved results, the tops of the protuberances rise above the bottoms of the immediately adjacent troughs by a vertical distance equal to at least about three times or 0.005 inch, 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. 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.

For good resolution of the resulting fiber bundles, the distance between the tops of the protuberances are preferably at least about 30 times the average diameter of the fibers of the starting material or 0.045 inch. Each of the forming apertures with which the backing means described is used should be at least about as wide as the horizontal distance between the tops of immediately adjacent protuberances.

During use of the apparatus of this invention, the apertured forming means and the backing means are spaced from each other to provide a fiber rearranging zone in which fiber movement may take place in response to applied fluid forces: The spacing may also be present while the apparatus of this invention is not in use, or itmay be present onlyrin use, produced for example by a bellying out effect in the backing means under the impact of the rearranging fluid directed against it, as described in my US. Pat. No. 2,862,251.

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

The higher "the pressure employed, the larger the quantity of water that is delivered, and as a result any 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.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be more fully described in connection with the accompanying drawings, in which:

FIG. 1 is a diagrammatic showing in elevation of one type of apparatus that can be employed in the present invention.

FIG. 2 is an enlarged diagrammatic plan view of a portion of a backing means that can be used in the apparatus of FIG. 1.

FIG. 3 is a cross sectional view taken along the line 3-3 of FIG. 2.

FIG. 4 is a further enlarged diagrammatic plan view of the element shown in FIG. 2, with the apertures of the apertured forming means used in conjunction therewith shown in dashed lines.

FIG. 5 is an enlarged fragmentary diagrammatic plan view of the foraminous portion of another backing means that can be used with the apparatus of FIG. 1, an aperture of the apertured forming means being shown in dashed lines.

FIG. 6 is a cross sectional view taken along the line 6-6 of FIG. 5.

FIG. 7 is a cross sectional view taken along lines 7-7 of FIGS. 5 and 6.

FIG. 8 is a photomicrograph of nonwoven fabric madein accordance with the present invention, shown at an original enlargement of five times.

FIG. 9 is a schematic drawing of another embodiment of a nonwoven fabric made in accordance with the present invention.

FIG. 10 is a photomicrograph of another fabric made in accordance with the present invention, shown at an an original enlargement of five times.

FIG. 11 is a photomicrograph -of a cross sectional view taken along a line similar to that shown as line 11-11 in FIG. 10, shown at an original enlargement of ten times.

FIG. 12 is a schematic drawing of another embodiment of a nonwoven fabric made in accordance with the present invention.

DETAILED. DESCRIPTION OF SPECIFIC FORMS OF THE INVENTION FIG. 1 shows one form of apparatus that may be used in accordance with the present invention. Full particulars of the basic apparatus of which this apparatus is a specific form, including methods of mounting, rotation, etc., are more fully described in U.S. Pat. No. 2,862,251 issued Dec. 2, 1958, and are incorporated in the present application by reference and thus need not be described in complete detailhere. In view of this reference, the apparatus of FIG. 1 will be described in general terms insofar as its essential elements are the same as in the patent just mentioned, and the novel feature used to manufacture nonwoven fabrics in accordance with the present invention, i.e., the backing means and its relationship to the apertured forming means, will be described in more detail.

The apparatus of FIG. 1 includes a rotatable apertured drum l5 suitably mounted on

flanged guide wheels

17 and 18. The drum has apertures 19 uniformly spaced over its entire surface,'with the remaining portions of the drum constituting land areas 20. The guide wheels are mounted for rotation on

shafts

25 and 26.

Inside the drum, a stationary manifold 27 to which a fluid is supplied through conduit 28 extends along the full width of the drum. On one side of the manifold is a series of nozzles 29 for directing the fluid against the inside surface of the drum.

About the greater portion of the periphery of the drum there is positioned a novel backing or support member 30. (The terms backing member and support member are used interchangeably throughout this description.) Support member 30, as shown in FIG. 2, has a continuouspattem of foraminous portions 50 and a discontinuous pattern of imperforate portions 51. In FIG. 2, the imperforate portions are round and arranged such that four of them lie 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 arranged in any discontinuous pattern over the support member; i.e., they may be aligned longitudinally and/or transversely, staggered, etc.

FIG. 3 shows a cross section of the backing means of FIG. 2. As seen, each discontinuous imperforate portion 51 of backing means 30 has a curved top surface that rises slightly above the top surface of foraminous portions 50 of the backing means. Because of the curved top surface, central portion 52 rises above edge portions 53 of discontinuous imperforate portion 51 of the backing means. Extreme edge portions 54 are slightly rounded. v

Support member 30 passes about drum l5 and separates from the drum at guide roll 31 which rotates on shaft 32. The support member passes downwardly around guide roll 33, rotating on shaft 34, then rearwardly over a vertically adjustable tensioning and tracking guide roll 35 rotating on shaft 36, and then around guide roll 37 on shaft 38. The member passes upwardly and around guide roll 39 rotating on shaft 40, to be returned about the periphery of the drum.

Apertured forming drum l5 and backing belt 30 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 a plurality of patterns of holes or other areas of low fiber density alternating and extending 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 15 rotates in the direction of the arrow shown, and support member 30 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 E- brous material 41 to be treated is fed between the drum and support member 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 nonwoven fabric 42 between the support member and apertured drum at point B."

A fibrous material 41 passes through the fiber rearranging zone, a liquid such as water is directed against the inner surfaces of rotatable apertured drum 15 by nozzles 29 mounted inside the drum, the liquid passes through apertures 19 into the fibrous web to produce rearrangement of the fibers of the web, and the water thence passes out through the backing means. Suction box 43 helps to remove this water before rearranged fabric 42 reaches takeoff point B.

The directions the streams of rearranging fluid projected through apertures 19 of apertured forming means 15 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 apertures 19 are determined by foraminous portions 50 and imperforate portions 51 of support member or backing means 30, it follows that the pattern of these areas helps determine the patterns of holes or other areas of low fiber density in the resultant fabric. The portions of the rearranging fluid in the areas where support member 30 is foraminous pass directly through both the web and the support member. This type of flow through adjacent apertures 19 of apertured forming means 15 and then through foraminous portions 50 of backing means 30 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 beneath land areas of apertured forming means 15 and above foraminous portions 50 of backing means 30.

The portionsof the rearranging fluid in each area where backing means is imperforate pass over the support member, and push fiber segments off the imperforate portions 51 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.

FIG. 4 gives a still further enlarged diagrammatic view ofa portion of backing means 30 used in the apparatus of FIG. 1. Discontinuous imperforate portions 51 are arranged such that four of the portions lie in a square pattern over the surface of the backing member. The remainder of the backing member is comprised of continuous foraminous portions 50. Forming apertures 19 of the apertured forming means 15 are shown in dashed lines in this FIG. 4. As seen, apertures 19 are arranged such that four of them lie in a square pattern on means 15.

As is seen, each of the discontinuous imperforate portions 51 underlies the entire area of a plurality of apertures 19, and in some cases a portion of the area of other such apertures. There are some apertures 19 under which imperforate portions 51 do not lie at all.

In the zone of closest spacing of each pair of immediately adjacent discontinuous imperforate portions 51 of backing means 30, the width of continuous interconnecting foraminous portions 50 is equal to at least about two times the distance between the centers of a pair of immediately adjacent apertures 19 of apertured forming means 15. This means that when a forming aperture 19 is centered above an interconnecting foraminous portion 50 between two imperforate portions 51, a hole or other area of low fiber density corresponding to that aperture will be produced, defined on both sides by yam-like bundles of closely associated and substantially parallel fiber segments.

When backing means 30 and apertured forming means 15 are employed in the method or apparatus of this invention as shown in FIG. 4, fiber segments that are in registry with discontinuous imperforate portions 51 of backing means 30 are moved by streams of rearranging fluid into surrounding areas of the fibrous layer and are there positioned in yarn-like bundles of closely associated and substantially parallel fiber segments to define a first pattern of holes or other areas of low fiber density arranged in accordance with the pattern of arrangement of imperforate portions 51. At the same time, fiber segments that are in registry both with forming apertures 19 and with foraminous portions 50 of backing means 30 are moved into surrounding areas of the fibrous layer to form similar yam-like bundles of fiber segments defining a second pattern of holes or other areas of low fiber density in accordance with the pattern of arrangement of those apertures 19 that overlie foraminous portions 50.

As is seen from FIG. 4, the holes or other areas of low fiber density in the first pattern are larger than the holes or other areas of low fiber density in the second pattern. In the embodiment shown, the area of each of the discontinuous imperforate portions 51 is approximately thirty times the area of each forming aperture 19, and thus the respective areas of low fiber density that correspond to these elements in the final fabric produced by use of this invention have approximately the same relative areas.

In the apparatus of FIG. 1, the relative positioning of backing means 30 and apertured forming means 15 with respect to the fibrous layer 41 being rearranged is maintained through the rearranging zone 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.

FIG. 5 gives an enlarged fragmentary diagrammatic plan view of the foraminous portion of another backing means that can be used with the apparatus of FIG. 1. 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 84 running vertically in FIG. 5 are straight, while wires 85 running horizontally in that figure weave alternately over and under wires 84. Protuberances 81 are present throughout foraminous portion 80 as the topmost part of each knee of a given strand 85 of the screen that is formed as the strand weaves over and under the strands 84 that lie perpendicular to it.

As a given strand 85 slants downward to pass under a strand 84 perpendicular to it, it crosses two other strands 85 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 86 forms a trough, such as trough 87 formed by crossing points 86 in FIGS. and 6, that lies between adjacent protuberances 81. The effectiveshape of troughs 87, as can be best seen in FIG. 6 (which shows a cross a plan view is given in verted triangle.

A'series of slightly deeper troughs 88 is formed between adjacent protuberances 81 but extending at right angles to troughs 87. As best seen in FIG. 7, the bottom of each trough 88 is formed by portions of straight strands 84, with successive protuberances 81 on each side of the trough forming the tops of the trough. As seen in FIG. 7, the effective shape of troughs 88 may be characterized as a shallow U-shape.

As shown in FIG. 5, a plurality of troughs 87 and a plurality of protuberances 81 alternate in one direction across the surface of foraminous portion 80 of the backing means. FIG- also shows that aplurality of troughs 88 and a plurality of protuberances 81 alternate in a direction perpendicular to troughs 87. Hence a plurality of troughs and a plurality of protuberances FIG. 5), is substantially an inalternate in both the longitudinal and transverse directions across the surface of foraminous portion 80 of the backing means.

Use in the method or apparatus of this invention of a backing means having foraminous portions such as element 80 shown in FIGS. 5 through 7 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 19 of forming means 15. The third pattern of areas of low fiber density is defined byyam-like bundles of fibersegments that have been positioned in

troughs

87 and 88 on the surface of foraminous portions 80 of the backing means.

To produce improved rearrangement of fibers into yarn-like bundles of closely associated and substantially parallel fiber segments positioned in

troughs

87 and 88, the vertical distance between the tops of protuberances 81 and the bottoms of the immediately adjacent troughs should be at least about three times, generally no more than about 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 87, thisdistance is the vertical distance indicated in FIG. 6 by the pair of dashed lines that pass, respectively, through the tops of protuberances 81 and the crossing points 86 that define troughs 87, The vertical distance from the bottom of each trough 88 to the tops of protuberances 81, on the other hand, is somewhat larger, being shown by FIGS. 6 to the diameter of a strand 85.

The relative postion of a forming aperture 19 and protuberances 81 of foraminous portion 80 of the backing means in one form of this invention is shown section of element80 of-which and 7 to be equal in dashed lines in FIG. 5. As is seen, aperture 19, 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 81.

FIG. 5 also shows that aperture 19 spans two protuberances 81 measured across foraminous portion in both the longitudinal and transverse directions. In the embodiment shown, each of the two protuberances 81 in registry with aperture 19 having a directional effect in one direction because of its proximity to other similar protuberances on backing means 30, and in the other direction for the same reason and in addition because of the'cross-sectional shape of the protuberance is effective in both the longitudinal and transverse directions.

Protuberance 81 opposite the upper left hand corner of aperture 19 in FIG. 5, through cooperation with protuberance 81 lying just below the lower left hand corner of aperture 19 in that same figure, is effective as a protuberance that defines one wall of trough 87 running vertically down the middle of aperture 19. At the same time, the first named protuberance 81, through cooperation with protuberance81 lying just outside the upper right hand corner of aperture 19 in FIG. 5, is effective as a protuberance that defines one wall of trough 88 running horizontally across the middle of aperture 19. In addition, the cross-sectional shape of each protuberance 81 (as best seen in FIGS. 5 and 7) exerts a directional effect on the fibers of the fibrous starting material by its sharper definition of the side walls of each trough extending horizontally across FIG. 5, i.e., on the side walls of each trough 88.

During use of this invention, apertured forming means 15 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 19 and the fibrous web pass directly through openings 89 between adjacent wires of woven screen 80. Other portions of the streams of rearranging fluid that have passed through apertures l9 strike the wires of woven screen 80, at protuberances 81 or at other portions of the wire, and are deflected sidewise before they pass out of the rearranging zone through openings 89.

The streams of rearranging fluid just described move some of the fiber segments that are in registry with apertures 19 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'deflne holes or other areas of low fiber density in a pattern corresponding to the pattern of apertures 19. 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 51 of backing means 30.

At the same time, the fluid rearranging forces move other fiber segments that are in registry with forming apertures 19 and overlie foraminous portions 80 into

troughs

87 and 88, 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 following are illustrative examples of use of the method and apparatus of this invention to produce patterned nonwoven fabrics:

EXAMPLE 1 In apparatus as illustrated in FIG. 1, a web 41 of loosely assembled fibers, such as may be obtained by carding, is fed between apertured forming means 15 and backing means 30. Theweb weight is about 450 grains per square yard, and its fiber orientation ratio approximately 7 to l in the direction of travel. The web contains viscose rayon fibers approximately 1 9/ 16 inches long, of l /2 denier.

Apertured forming means 15 has about 165 substan tially round'holes per square inch, each approximately 0.045 inch in diameter, arranged in a diamond pattern over the forming means. Each aperture 19 is spaced approximately 0.018 inch in the diagonal direction from the immediately adjacent aperture on the drum.

The foraminous portions of backing means 30 are comprised of a woven nylon screen of approximately 28 X 34 mesh or substantially 952 openings per square inch.

Imperforate portions 51 of backing means 30 are smooth round metal members of a diameter of approximately A inch andhaving a cross sectional shape similar to that shown in FIG. 3. They are distributed over the area of backing means 30 in a diamond pattern, with a space of approximately /a inch from each portion 51 to the nearest other portion 51 in a diagonal direction. Central portions 52 of elements 51 rise 0.012 inch above the plane of the top surface of continuous foraminous portions 50 of the backing means, and edge portions 53 rise about 0.010 inch above that plane.

Except for the diamond patterns of imperforate portions 51 and apertures 19, apertured forming means 15 and support means 30 are disposed generally as shown in FIG. 4.

Water is projected from nozzles 29 through apertures 19 in apertured forming means 15, and thence through fibrous web 41 and backing means 30.

After a given portion of fibrous web 41 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 15, the rearranged nonwoven fabric 42, and backing means 30 brings the rearranged fabric over vacuum drying means 43, which helps to remove the water remaining in the fabric. Fabric 42 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. 8, which has a plurality of patterns alternating and extending throughout the fabric, is produced.

Nonwoven fabric 90 of FIG. 8 contains a first pattern of holes 91, each of which holes overlie a discontinuous imperforate portion 51 of backing means 30, and is defined by yarn-like bundles 92 of closely associated and substantially parallel fiber segments.

In addition, nonwoven fabric 90 contains a second pattern of areas of low fiber density 93, arranged in accordance with the pattern of arrangement of apertures 19 in apertured forming means 15 that overlie foraminous portions 50 of backing means 30. Each of these areas 93 is defined by yam-like bundles 94 of closely associated and substantially parallel fiber segments.

Each hole 91 appears from FIG. 8 to be approximately 25 times the size of each area of low fiber density 93, or a little bit larger. This is consistent with the relative size of discontinuous imperforate portions 51 of backing means 30 and apertures 19 of apertured forming means 15 that are included in the apparatus, with which the fabric of FIG. 8 was made. The round apertures have a diameter of about 0.045 inch, which gives each of them an area of about 0.0064 square inches. The imperforate portions of the backing means have a diameter of about 54 inch, which gives each of them an area of about 0.197 square inches, or in other words about 30 times the area of each aperture of the apertured forming means.

It is evident from FIG. 8 that during the production of the fabric there illustrated, imperforate portions 51 of backing means 30 underlie 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 91 is separated by at least one of the smaller holes or areas of low fiber density, such as those designated 93 in FIG. 8. To produce this result, the width of the interconnecting foraminous portions 50 of backing means 30 (or, in other words, the closest diagonal spacing between imperforate portions 51 of the backing means, which is about As inch or 0.125 inches) is equal to about two times the distance between the centers of a pair of immediately adjacent apertures 19 of forming means 15 (or, in other words, two times 0.063 inch).

EXAMPLE 2 FIG. 9 is a schematic drawing of another nonwoven fabric made in accordance with the present invention, 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. 9 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 has a first pattern of larger holes 101 .that corresponds to the pattern of discontinuous imperforate portions 51 of backing means 30. Each larger hole 101 is defined by a plurality of yam-like bundles 102 of closely associated and substantially parallel fiber segments.

The fabric of FIG. 9 also contains a second pattern of smaller areas of low fiber density 103 in locations where apertures 19 of apertured forming means 15 coincide with continuous foraminous portions 50 of backing means 30. Holes 103 are likewise defined by yarnlike bundles 104 of closely associated and substantially parallel fiber segments.

In nonwoven fabric 100, heavier yam-like bundles 105 of closely associated and substantially parallel fiber segments extend generally in the machine direction of the starting fibrous material. These heavier yam-like bundles 105 assist in defining areas of low fiber density 101 (as at 106), as well as areas of low fiber density 103 (as at 107).

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 yam-like bundles are EXAMPLE 3 In apparatus as illustrated in FIG. 1, a web .41 of loosely assembled fibers of the type commonly called an isotropic web is fed between apertured forming means 15 and backing means 30. 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 9/16 inches long of l l denier.

The apertured forming means 15 used in this example is the same as that employed in Example 1.

Backing means 30 is the same'as the backing means employed in Example 1, except that discontinuous imperforate portions 51 arearranged in a square pattern over the surface of backing means 30, with a space of approximately 150- inch. between each portion 51 and the nearest other such portion in both the longitudinal and transverse directions.

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

Nonwoven fabric 110 of FIG. 10 contains a first pattern of holes 111, eachof which is defined by yarn-like bundles 112 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 51 of backing means 30.

In addition, nonwoven fabric 110 contains a second I pattern of areas of low fiber density 113, arranged in accordance with the pattern of arrangement of those apertures 19 in apertured forming means that overlie foraminous portions 50 of backing means'30. Each of these areas 113 is defined by yarn-like bundles 114 of closely associated and substantially parallel fiber segments.

Each area 111 appears from FIG. 10 to be approximately times the size of each area of low fiber density 113, or a little bit larger. This is consistent with the relative size of imperforate portions 51 and apertures 19 in the apparatus used to make the nonwoven fabric of FIG. 10, since the former have an area about times as large as the area of the latter.

It is evident from FIG. 10 that during the production of the fabric there illustrated, imperforate portions 51 of backing means 30 underlie some, but not all, of the apertures in the apertured forming means. Each pair of immediately adjacent large areas of low fiber density 111 spans at least one of thesmaller areas of low fiber density such as those designated at 113' in FIG. 10. To

. produce this result, the width of the interconnecting foraminous portions 50 of backing means 30 at theirnar rowest portion is equal to about two times the distance between the centers of a pair of immediately adjacent apertures 19 of forming means 15, just as was true in Example 1 above.

A cross sectional view of the fabric of FIG. 10 is given in'FIG. ll, taken along a line similar to that shown as line 11-11 in FIG. 10, and with an enlargement twice the enlargement in that figure. Yam-like bundles of fiber segments 112 define the larger areas of low fiber density 111. Smaller areas of low fiber density 113 are seen in cross section, defined by yarn-like bundles of fiber segments 114.

EXAMPLE 4 Apparatus, starting material and operating conditions as described in Example 2 are used in this example, except that the foraminous portions of the backing means 30 are similar to element of FIGS. 5 through 7. These foraminous portions comprise a woven nylon screen of approximately 14 X 18 mesh or substantially 252 holes per square inch. The tops of protuberances 81 are about 0.005 inch above the bottoms of the immediately adjacent troughs 87, or in other words a vertical distance a little more than three times the 0.0015 inch diameter of fibers of 1 /z denier of the starting material used here. Troughs 88 are slightly deeper than troughs 87, being about 0.007 inch below the tops of protuberances 81.

The horizontal distance between the tops of immediately adjacent protuberances 81 is about 0.055 inch in one direction and about 0.070 inch in the other, or in other words about 37 and about 47 times, respectively, thElifitIlS Tnchdia mlfir of'the asrsbmernmag material. Each aperture 19 of apertured forming means 15 is about 0.045 inch in diameter, or the same general magnitude as the horizontal distance between the tops of immediately adjacent protuberances 81.

FIG. 12 gives a schematic drawing of a portion of the resulting nonwoven fabric.

Nonwoven fabric 'has a first pattern of holes 121 that corresponds to the pattern of discontinuous imperforate portions 51 of backing means 30. Each larger area 121 is defined by a plurality of yarn-like bundles 122 of closely associated and substantially parallel fiber segments.

The fabric also contains a second pattern of smaller holes or areas of low fiber density 123 in locations where apertures 19 of apertured forming means 15 coincide with continuous foraminous portions 50 of backing means 30. Areas 123 are likewise defined by yarn- Iike bundles 124 of closely associated and substantially parallel fiber segments. 1

In nonwoven fabric 120, heavier yarn-like bundles 125 of closely associated and substantially parallel fiber segments extend generally in the machine direction of the starting fibrous material. These heavier yarn-like bundles 125 assist in defining areas of low fiber density 121 (as at 126), as well as areas of low fiber density 123 (as at 127).

Still a third pattern of holes or other areas of low fiber density 128 lies within the pattern of smaller areas of low fiber density 123. The third pattern is defined by yarn-like bundles 129 of closely associated and substantially parallel fiber segments positioned in

troughs

87 and 88 of foraminous portions 80 of t e backing means shown in FIGS. 5 through 7. i

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

The rearranged web or fabric produced by the practice 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 includes in an aqueous or nonaqueous 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 in powder form before, during or after rearrangement, 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 members and their arrangement 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, or both factors, no binder at all need be employed to provide a usable fabric.

To assist in moving rearranging fluid through the layer of fibrous starting material during use of this invention, and to help bring about the necessary movement of fiber segments to produce a rearranged nonwoven fabric, a vacuum may be applied to the opposite side of the backing means simultaneously with the application of fluid rearranging forces to the fibrous starting layer. The vacuum employed is of the order of about 1 to about 4 inches of mercury, preferably about 2 inches of mercury. In general, the larger the foraminous areas of the backing means are, the lower the vacuum used may be. The vacuum may be applied, for example, by vacuum box 44, the side of box 44 adjacent the outer surface of rotating drum being provided with narrow slots 45.

If the apertured forming means used in the apparatus of this invention is sufficiently flexible, the application of vacuum as just described causes the land areas of the forming means to clamp the fibrous starting material so tightly against the backing means that the fluid rearranging forces are not capable of effecting fiber rearrangement in those particular areas. These areas in which fiber rearrangement is prevented add still another pattern of fiber segments that extends throughout the fabric, to add to the aesthetic appeal of the fabric.

The above detailed description has been given for portions that are imperforate and portions that are foraminous, said imperforate portions being arranged in a discontinuous pattern and the remainder of said backing means being foraminous and lying between and interconnecting the imperforate portions; apertured forming means spaced from said backing means during use of the apparatus to provide a zone in which said layer of fibrous starting material may be positioned and in which fiber movement in directions parallel to said backing means is permitted in response to applied fluid forces, the apertures in said forming means being longitudinally and transversely spaced with land areas therebetween, said forming apertures being larger than the foramina in said foraminous portions of the backing means, each of said imperforate portions of the backing means underlying the entire area of at least four of the apertures in said apertured forming means, each of said imperforate portions being shaped to provide a compact area with the maximum dimension of the area of each imperforate portion being no more than about four times the minimum dimension of said area, the width of each of said interconnecting foraminous portions between immediately adjacent imperforate portions of the backing means being equal to at least about two times the distance between the center of a pair of immediately adjacent apertures of the apertured forming means; means for moving said backing means and said apertured forming means, with a layer of fibrous starting material positioned therebetween, through a rearranging zone without any translatory motion between said two means and the fibrous layer; and means for projecting streams of rearranging fluid through said apertures in the apertured forming means, and then against said fibrous layer to pass therethrough, some of said fluid streams thereafter striking said imperforate portions of the backing means and being deflected thereby in sidewise directions, and all of said fluid streams passing through and beyond said foraminous portions of the backing means.

2. The apparatus of claim 1 in which said imperforate portions of the backing means rise above the plane of the top of said foraminous portions of the backing means at least 1/64 inch, with the central portions of each of said imperforate members rising higher than the edge portions thereof.

3. The apparatus of claim 1 in which each of said imperforate portions of the backing means underlies the entire area of from about 10 to of the apertures in the apertured forming means.

4. The apparatus of claim 1 in which each of said foraminous portions of the backing means has a plurality of protuberances and troughs alternating across the surface thereof in both the longitudinal and transverse directions, the tops of said protuberances on the backing means rising above the bottoms of the immediately adjacent troughs by a vertical distance of at least 0.005 inch, the horizontal distance between the top of one of said protuberances and the top of the protuberance immediately adjacent it on the backing means is at least about 0.045 inch and each of the apertures in the apertured forming means is at least as wide as said horizontal distance.

m3 I INI'lED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 318 3 Dated April 2,l97

Inventor(5) Kalwaites It is certified that: error appears in the above-identified patent and that said Let heirs Patent are hereby corrected as shown below:

F! In Colulnn 6, line 11, "5" should read as I? In coluhn' 'r, line 3 9, "1/8" should read l/8" In Column 8, line "l/32" should read l/32" In Col umn 8, line #6, "0.005" should read .005

In 8, line 58, "0.0 6" should read -".0 6";

In Colurr n 13, line 60, "8?,The" should read 87. The

In Column 15, line .60, "overlie" should read overlies I In Column 17, line 10, "However" should read Heavier In colhmh 17, line 30, "150" should read l/8" In column 19, line 8, "includes" should d included In Column 19 line 3 "1" should read l" In Column 20, line 60, "0.0 5" should read .o

sighed and sealed this 4th day of February 1975.

(SEAL) Attests McCOY M. GIBSON JR. 0'. MARSHALL DANN Attesting- Officer Commissioner of Patents

Claims

1. Apparatus for producing a patterned nonwoven fabric having a plurality of patterns of areas of low fiber density that alternate and extend throughout said fabric, from a layer of fibrous starting material whose individual fibers are in mechanical engagement with one another but are capable of movement under applied fluid forces which comprises: backing means for said layer of fibrous starting material, said means having portions that are imperforate and portions that are foraminous, said imperforate portions being arranged in a discontinuous pattern and the remainder of said backing means being foraminous and lying between and interconnecting the imperforate portions; apertured forming means spaced from said backing means during use of the apparatus to provide a zone in which said layer of fibrous starting material may be positioned and in which fiber movement in directions parallel to said backing means is permitted in response to applied fluid forces, the apertures in said forming means being longitudinally and transversely spaced with land areas therebetween, said forming apertures being larger than the foramina in said foraminous portions of the backing means, each of said imperforate portions of the backing means underlying the entire area of at least four of the apertures in said apertured forming means, each of said imperforate portions being shaped to pRovide a compact area with the maximum dimension of the area of each imperforate portion being no more than about four times the minimum dimension of said area, the width of each of said interconnecting foraminous portions between immediately adjacent imperforate portions of the backing means being equal to at least about two times the distance between the center of a pair of immediately adjacent apertures of the apertured forming means; means for moving said backing means and said apertured forming means, with a layer of fibrous starting material positioned therebetween, through a rearranging zone without any translatory motion between said two means and the fibrous layer; and means for projecting streams of rearranging fluid through said apertures in the apertured forming means, and then against said fibrous layer to pass therethrough, some of said fluid streams thereafter striking said imperforate portions of the backing means and being deflected thereby in sidewise directions, and all of said fluid streams passing through and beyond said foraminous portions of the backing means.

3. The apparatus of claim 1 in which each of said imperforate portions of the backing means underlies the entire area of from about 10 to 100 of the apertures in the apertured forming means.