US3750236A

US3750236A - Method and apparatus (discontinuous imperforate portions on backing means of open sandwich)

Info

Publication number: US3750236A
Application number: US00225263A
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: 1973-08-07
Anticipated expiration: 1990-08-07

Abstract

A method and 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 supporting the starting web upon a backing means that is foraminous except for a discontinuous pattern of imperforate portions and has protuberances and troughs alternating across its foraminous portions, then directing fluid rearranging forces substantially uniformly and continuously across the surface of the web, causing some of the fluid streams to strike the imperforate portions of the backing means, and others to strike the protuberances on the backing means, to deflect the same, all of the fluid streams ultimately passing through the foraminous portions of the backing means. Each discontinuous imperforate portion extends along the surface of the backing means in each direction a distance at least about twice the horizontal distance between the bottoms of a pair of immediately adjacent troughs. Each pair of immediately adjacent discontinuous imperforate portions spans between them at least one protuberance and a trough on each side of the protuberance. 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 protuberances on the foraminous portions of the backing means.

Description

United States Patent [1 1 Kalwaites Aug. 7, 1973 METHOD AND APPARATUS (DISCONTINUOUS IMPERFORATE PORTIONS ON BACKING MEANS OF OPEN SANDWICH) [75] Inventor: Frank Kalwaites, Gladstone, NJ.

[73] Assignee: Johnson & Johnson, New Brunswick,

22 Filed: Feb. 10, 1972 21 Appl. No.: 225,263

Related U.S. Application Data [63] Continuation of Ser. No. 22,313, March 24, 1970,

Primary ExaminerDorsey Newton Attorney-Robert L. Minier and Leonard P. Prusak [57] ABSTRACT A method and 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 supporting the starting web upon a backing means that is foraminous except for a discontinuous pattern of imperforate portions and has protuberances and troughs alternating across its foraminous portions, then directing fluid rearranging forces substantially uniformly and continuously across the surface of the web, causing some of the fluid streams to strike the imperforate portions of the backing means, and others to strike the protuberances on the backing means, to deflect the same, all of the fluid streams ultimately passing through the foraminous portions of the backing means. Each discontinuous imperforate portion extends along the surface of the backing means in each direction a distance at least about twice the horizontal distance between the bottoms of a pair of immediately adjacent troughs. Each pair of immediately adjacent discontinuous imperforate portions spans between them at least one protuberance and a trough on each side of the protuberance. 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 protuberances on the foraminous portions of the backing means.

3 Claims, 10 Drawing Figures PATENTED M18 7 I975 SHEEI 2 BF 4 INVENTOR FKAWK K44 wan-'5 ATTORNEY P'ATENTEB lug 7 B13 SHEET l 0F 4 INVENTOR FR K KALW/MTES 'rw flw ATTORNEY LIA.

METHOD AND APPARATUS (DISCONTINUOUS IMPERFORATE PORTIONS ON BACKING MEANS OF OPEN SANDWIC This is a continuation application of my co-pending application Ser. No. 22, 313, 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 capable of 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 that help to define the apertures (holes) or other areas of low fiber density contained in the fabllC.

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 US. Pat. No. 2,862,251, which discloses the basic method and apparatus of which the present invention is a specific form, and in US. Pat. Nos. 3,081,500 and 3,025,585.

The nonwoven fabrics made by the methods and apparatus disclosed in the patents just mentioned contain apertures or holes or other areas of low fiber density, out-lined 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 (1) 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 known methods for producing rearranged nonwoven fabrics is to support a loose fibrous web or layer upon a permeable backing member that has protuberances or tapered projections" spaced across its surface, with troughs or low areas between the protuberances. Streams of rearranging fluid are applied substantially uniformly and continuously over the entire surface of the loose fibrous web or layer, and after the streams pass through the fibrous material some of them strike the protuberances on the backing means and are diverted in sidewise directions to cause fiber segments to move from the area adjacent the high point of each protuberance into the immediately adjacent troughs. All the streams then pass through the openings in the permeable backing means and leave the rearranging zone.

The effect of these fluid rearranging forces is to pack groups of fiber segments into interconnected yarnlike bundles of closely associated and substantially parallel fiber segments and to position them in the troughs on the backing means so as to define a pattern of areas of low fiber density throughout the resulting nonwoven fabric.

In this prior art method, the backing member is uniformly permeable throughout its area in order to provide an unimpeded route by which the streams of rearranging fluid can be quickly carried away after they have moved fiber segments from the protuberances into the troughs of the backing means. Care is always taken in any fluidrearrangement to avoid loss of web identity through flooding (US. Pat. No. 2,862,251, col. 2, line 60 to col. 3, line 12), and with the specific prior art method under discussion it is said to be essential that the backing member be permeable to the passage of fluid from the applied streams, so that the fluid may pass freely through the backing member and away from the layer of fibers rather than having some or all of the fluid reflected back in the same general direction from which it is applied (U.S. Pat. No. 3,025,585, col. 2, lines 38-48).

The fiber segments rearranged by the prior art method referred to are moved laterally only as indicated, which is no farther than from the high point of a protuberance to the low point of an immediately adjacent trough. This will usually be about one-half the horizontal distance from the bottom of one trough or low point to the bottom of the next.

SUMMARY OF INVENTION l have now discovered that, unexpectedly, one can block off substantial portions of the otherwise permeable backing or support member in the prior art method just described, to interrupt and impede the flow of rearranging fluid through the backing member, and still not impede satisfactory rearrangement of the fibers of the fibrous starting material by the protuberances on the backing means into a nonwoven fabric containing yarn-like bundles of fiber segments and having well defined apertures in a plurality of patterns that alternate and extend throughout the fabric. Moreover, contrary to the prior art method, the fiber segments that are rearranged into yarn-like bundles of closely associated and substantially parallel fiber segments are moved laterally for a distance substantially greater than the distance between the high point of a protuberance and the bottom of its immediately adjacent trough or low point.

In the practice 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 layer of fibrous starting material is supported in a fiber rearranging zone that has an entry side and an exit side and in which fiber movement in directions parallel to the plane of the fibrous material is permitted in response to applied fluid forces. The fiber rearranging zone is subdivided into barrier regions that are arranged in a discontinuous pattern, and deflecting regions that are continuous and lie between and interconnect the barrier regions.

Streams of rearranging fluid, preferably water, are projected into the fibrous starting material substantially uniformly and continuously across its surface, in a direction perpendicular to the fibrous layer at the entry side of the rearranging zone. The streams of rearranging fluid are comprised of three categories first portions that pass through the deflecting regions of the rearranging zone, second portions that pass through the barrier regions, and third portions that pass through the deflection regions but in a different manner than the first portions.

The first portions of the rearranging fluid are passed through the initial part of the deflecting regions, as the layer of fibrous starting material lies in said regions, toward a plurality of dispersal points in the deflecting regions lying adjacent the exit side of the rearranging zone. Each of these dispersal points is surrounded by fiber accumulating zones. At least one dispersal point and its associated fiber accumulating zones lie between each barrier region and its adjacent barrier regions at all points around the perimeter of the first mentioned barrier region.

At each dispersal point, the first portions of rearranging fluid are deflected diagonally and downwardly away from the perpendicular direction of their entry into the rearranging zone, and are moved into the area immediately surrounding the dispersal point. This movement of the rearranging fluid moves fiber segments lying adjacent the dispersal point into the area around that point, and positions them there in yarn-like bundles of closely associated and substantially parallel fiber segments. Some of these yarn-like bundles lie in fiber accumulating zones that are located in peripheral portions of the deflecting regions, and some lie in accumulating zones that are located between immediately adjacent dispersal points.

The second portions of rearranging fluid are passed through the parts of the layer of fibrous starting material that lie in the barrier regions of the fiber rearranging zone, and cause movement of at least some segments of the fibers in those regions transverse to the direction of travel of the projected streams. At the exit side of the rearranging zone, the passage of these second portions of rearranging fluid out of the parts of the fibrous layer that lie in the barrier regions is blocked, and the fluid is deflected sidewise into the deflecting regions of the rearranging zone. This movement of the rearranging fluid moves fiber segments that lie in the barrier regions into at least some of the yam-like bundles of closely associated and substantially parallel fiber segments mentioned above.

The first and second portions of the rearranging fluid that have been deflected as described are then actively mingled, and the intermingled fluid is passed out of the fiber rearranging zone through spaced exits in the deflecting regions at the exit side of the rearranging zone. At the same time, third portions of fluid are intermingled with the first and second portions, to be passed out of the same exits. The third portions of fluid are projected into the fibrous starting material and are moved to the exits referred to without passing through a dispersal point or a barrier region.

To assist in moving all the rearranging fluid through the layer of fibrous starting material and in rearranging the fiber segments of that layer, a vacuum is applied at the exit side of the fiber rearranging zone.

The result of application of the fluid rearranging forces just described is to form a nonwoven fabric having yarn-like bundles of fiber segments that define a first pattern of areas of low fiber density arranged in accordance with the pattern of arrangement of the barrier regions of the rearranging zone, and a second pattern of areas of low fiber density arranged in accordance with the pattern of arrangement of the dispersal points in the deflecting regions of the fiber 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, with continuous foraminous portions lying between and interconnecting the imperforate portions. The continuous foraminous portions of the backing means have protuberances and troughs alternating across the surface of such portions in both the longitudinal and transverse directions.

Each discontinuous imperforate portion extends along the surface of the backing means in each direction for a distance at least about twice the horizontal distance from the bottom of one of said troughs in the foraminous portion of the backing means to the bottom of the trough immediately adjacent and parallel to it. This doubles the average distance fiber segments must be moved laterally to bring them into yarn-like bundles in adjacent troughs of the backing means. By the same token, it multiplies by four times the quantity of fluid that must be disposed of in any area lying between adjacent troughs, while increasing by only two times the perimeter of that area out of which the fluid flows in order to leave the rearranging zone.

Each imperforate portion of the backing means may, if desired, rise above the plane of the tops of the foraminous portions of the backing means, with the central portions of the imperforate member rising higher than the edge portions thereof. However, it is not necessary that the imperforate portions constitute tapered projections as in the prior art method mentioned above, and if desired they may even be flush with the tops of the foraminous portions of the backing means and fiber arrangement is still achieved.

In the practice of this invention, streams of rearranging fluid, preferably water, are applied substantially uniformly and continuously across the surface of the layer of fibrous starting material as it is supported on the backing means just described. The streams pass through the fibrous layer and strike the backing or support means, some striking the imperforate portions of thebacking means and others striking the protuberances on the foraminous portions of the backing means. In either case, the streams are deflected in sidewise directions and join other streams of rearranging fluid that pass through the openings of the continuous foraminous portions of the backing means without striking the backing means.

To assist in moving the rearranging fluid through the layer of fibrous starting material and in rearranging the fibers of that layer, a vacuum is applied on the opposite side of the backing means from the fibrous starting material.

As the various streams of rearranging fluid follow their courses described, they cause fiber segments that overlie the protuberances on the foraminous portions of the backing means to move into troughs lying between those protuberances, and to be positioned there in yarn-like bundles of closely associated and substantially parallel fiber segments. At the same time, other streams of rearranging fluid cause fiber segments that overlie the discontinuous imperforate portions of the backing means to be moved into surrounding areas of the fibrous layer, where they are also consolidated into yarn-like bundles of fiber segments, in troughs located in peripheral portions of the foraminous portions of the backing means.

The resulting nonwoven fabric has a first pattern of areas of low fiber density, defined by yarn-like bundles of fiber segments, that corresponds to the pattern of the discontinuous imperforate portions of the backing means. In addition, thefabric has a second pattern of areas of low fiber density, defined by yarn-like bundles of fiber segments positioned in the troughs between adjacent protuberances on the foraminous portions of the backing means, that corresponds to the pattern of the protuberances on those foraminous portions of the backing means.

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 against such a fibrous material supported on partially imperforate backing means of the kind employed in this invention, one would expect that the streams would simply mat the interentangled fibers down against the imperforate portions of the backing means, so that there would be no fiber rearrangement produced there at all. This effect would be expected to be even more pronounced when each discontinuous imperforate portion of the backing means is of such asize that it extends in each direction along the surface of the backing means for a distance atleast twice the horizontal distance between immediately adjacent troughs on that surface, for in that situation the streams of rearranging fluid would strike an even greater obstacle to a rapid exit from the fiber rearranging zone.

Surprisingly, it has been found that obstructing the flow of fluid rearranging streams away from the rearranging zone by providing discontinuous imperforate portions of substantial size in the backing means does not have any undesirable result, nor prevent the production of excellent apertured rearranged nonwoven fabrics having a plurality of patterns extending throughout the fabric.

FURTHER DESCRIPTION OF INVENTION The basic method and apparatus of this invention are shown and described fully in my U.S. Pat. No. 2,862,25l, 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 method and apparatus of the present invention which is the provision of discontinuous barrier regions (defined, for example, by spaced imperforate members on a backing means) to block and deflect portions of the streams of rearranging fluid at the exit side of a fiber rearranging zone the remainder of which is comprised of continuous deflecting regions including dispersal points surrounded by fiber accumulating zones (for example, foraminous portions of a backing means having alternating protuberances and troughs) is described in detail in this application.

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, air-laid webs, or webs formed by liquid deposition. Thewebs 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 with the method or apparatus of this invention 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 polyanides, 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% inches.

Satisfactory products may be produced in accordance with this invention from starting webs weighing between grains per square yard to 2,000 grains per square yard or higher. With heavier web weights, as discussed below, the difference in elevation between the dispersal points and the fiber accumulating zones in the deflecting region of a fiber rearranging zone (for example, the protuberances and troughs, respectively, on the foraminous portions of a backing means) must be more pronounced in order to achieve the bundling that is a necessary part of this invention.

Continuous foraminous portions of backing means. As already indicated, in one form of this invention a backing means is employed that has imperforate portions arranged in a discontinuous pattern to provide barrier regions in the fiber rearranging zone, with con tinuous foraminous portions lying therebetween. The continuous foraminous portions of the backing means are provided throughout their surfaces with a plurality of protuberances and troughs alternating across those surfaces, and thus comprise deflecting regions containing dispersal points each of which is surrounded by fiber accumulating zones.

As illustrated in the drawings below, for improved results the tops of the protuberances on the foraminous portions of the backing means rise above the bottoms of the immediately adjacent troughs by a distance equal to at least about three times the average diameter of the fibers in the layer of fibrous starting material or at least 0.005 inch. Preferably, the distance is equal to about ten times the average diameter of those fibers, especially when the web weight of the fibrous starting material is of the order of 800 grains per square yard or higher. It also becomes more important to have prominent protuberances on the continuous foraminous portions of the backing means the greater is the area of the discontinuous imperforate portions of the backing means, since a large imperforate portion increases the number of loose fiber ends that will be washed off those imperforate portions to be added to the fibrous web already lying above the foraminousportions of the backing means.

The fibrous starting material used with the method and apparatus of this invention is comprised of closely intertwined and interentangled fibers arranged (depending upon the degree of fiber orientation in the layer) in a more or less helter-skelter fashion. Some of the fibers of the starting material will by random chance lie generally parallel to the troughs on the continuous foraminous portions of the backing means over which they lie, but the great majority of the fibers will lie at an angle to the longitudinal axes of the troughs, and a substantial number of these will lie at angles of 45 or more to such an axis.

In the practice of this invention, the movement of fiber segments into closer association and substantial parallelism with each other in yarn-like bundles in the troughs on the continuous foraminous portions of the backing means is more likely to occur with those fiber segments in the starting material that already lie only a relatively few degrees away from a position parallel to the longitudinal axis of a trough. To put it the other way, this type of movement is more difficult the greater the angle between a given fiber segment and the axis of the trough, and when fiber segments lie at too great an angle to the longitudinal axis of a trough, they simply continue to lie at that angle, matted down against the backing means by the force of the rearranging fluid. For the greater the angle between the fiber segment and the trough axis, the shorter is the portion of the fiber that bridges the trough, and the more difficult it is for the rearranging fluid forces to get a purchase" on the fiber segment to turn it around into a position parallel with the trough axis.

Likewise, the narrower the troughs are on the foraminous portions of the backing means, the more difficult it is for the rearranging fluid forces to get a purchase" on the short portion of the fiber segment that bridges the trough, to swing that segment around into a position parallel to the axis of the trough, to be consolidated there to form a yarn-like bundle with other similarly positioned fiber segments. The force of the vacuum assist employed with this invention is of course added to the force of the other rearranging fluid. with the use of a vacuum assist, the distance between immediately adjacent protuberances on the backing means, which determines the width of a trough from the top of one side to the other, is ordinarily equal to at least about times the average diameter of the fibers of the fibrous starting material. or at least 0.025.

The minimum spacing of protuberances just mentioned, which affects the width of the troughs lying between immediately adjacent protuberances, also assists in providing good visual resolution between various yarn-like bundles of fiber segments in the fabric resulting from the practice of this invention. For if the protuberances are too closely spaced and the troughs between them are too narrow, yarn-like bundles of fiber segments may be accumulated in the troughs but will not be discernible one from the other, because each one merges into the next adjacent similar bundle of fiber segments. If the web weight of the fibrous starting material is high, the distance between immediately adjacent protuberances on the foraminous portions of the backing means should be increased, or otherwise the yarn-like bundles of fiber segments will be masked out by the same merging phenomenon just mentioned.

The continuous foraminous portions of the backing means are sufficiently wide that, with the appropriate web weight in the starting material, good formation of yarn-like bundles of fiber segments can be effected above those foraminous portions. Thus, each continuous foraminous portion has a width-at its narrowest part sufficient to include at least one protuberance and a trough on each side of the protuberance. This minimum width for each continuous foraminous portion of the backing means produces a minimum of one well defined hole or other area of low fiber density corresponding to the protuberance on the backing means, with yarn-like bundles of fiber segments positioned in the troughs surrounding the protuberance.

There is no maximum limit on the width of the foraminous portions ofthe backing means. That dimension is determined only by the pattern desired in the nonwoven fabric to be produced. Thus, the width of a continuous foraminous portion may be as much as five or 10 times the horizontal distance between adjacent troughs, or even more.

The foraminous portions of the backing means used in this invention are of sufficient size to occupy together at least about 10 percent, and preferably about 30 percent or more, of the total area of the backing means.

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

Each discontinuous imperforate portion of the backing means extends along the surface of the backing means a distance equal to at least about two times, and preferably three times, the horizontal distance from the center of one of the troughs on the backing means (i.e., a fiber accumulating zone) to the center of the trough immediately adjacent and parallel to it. If desired, this dimension of a discontinuous imperforate portion may be as much as five times the horizontal distance between the center of adjacent troughs, or even more.

The maximum dimension of each discontinuous portion may be greater than the average length of the fibers in the fibrous starting material, and all the fibers may still be moved off those imperforate portions into surrounding areas of the fibrous layer. However, 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. Control of fiber movement is thus more effective if the maximum dimension of each discontinuous imperforate portion is substantially less than the average fiber length, for example, not more than 1 inch maximum dimension, and preferably not more than 1 inch to k inch maximum dimension, when fibers having an inch-and-a-half staple length are employed.

lf one dimension of a discontinuous imperforate portion of the backing means is made smaller, the other may be increased. 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, fiber segments will be moved off the imperforate portion more readily. 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, there will be more tendency for bridging of fibers across the imperforate portion of the backing means to occur.

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.

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 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 one sixty-fourth inch above the plane of that surface, and preferably by about one thirty-second inch or onesixteenth inch for starting fibrous webs having web weights in the range of from about 100 to about 1,000 grains per square yard. The height of the imperforate portions may be even greater without interfering with fiber rearrangement, but too great a height for these members may interfere with removal of the rearranged fabrics.

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 yam-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.

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.

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

Application of vacuum. The vacuum applied to the opposite side of the backing means simultaneously with the application of fluid rearranging forces to the fibrous starting layer is of the order of about 1 inch to about 4 inches of mercury, preferably about 2 inches of mercury. I

Additional vacuum may be used to advantage after the rearranged fabric has moved out of the rearranging zone, in order to help remove excess liquid from the fabric before the fabric is removed from tha backing means.

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

FIG. 1 is a diagrammatic showing in elevation of one type of apparatus that may 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 sectionalview taken'along the line 3-3 of FIG. 2.

FIG. 4 is an enlarged fragmentary diagrammatic plan view of one of the foraminous portions of the backing means of FIG. 2.

FIG. 5 is a cross sectional view taken along line 5-5 of FIG. 4.

FIG. 6 is a cross sectional view taken along line 6-6 of FIGS. 4 and 5.

FIG. 7 is a schematic perspective representation of the paths followed by various streams of rearranging fluid as they pass through the foraminous member shown in FIGS. 4 through 6.

FIG. 8 is a schematic plan representation of the paths followed by the streams of rearranging fluid shown in perspective in FIG. 7.

FIG. 9 is a photograph of a nonwoven fabric made in accordance with the present invention, shown in the original drawing at actual size.

FIG. 10 is a photomicrograph of the nonwoven fabric of FIG. 9, shown at an original enlargement of fibe times.

DETAILED DESCRIPTION OF SPECIFIC FORM OF THE INVENTION FIG. 1 shows one form of apparatus that may be used in accordance with the present invention.

In this apparatus, horizontal frame members 2 are supported by

legs

3 and 4. At the feed end of the machine (on the left hand side of FIG. 1), a pair of vertical frame members 5 extend upwardly above horizontal frame members 2, with a pair of wet-

out rolls

6 and 7 rotatably mounted between them. Wet-out roll 6 is partially immersed in a water pan 8, and its shaft 9 is journalled in bearings (not shown) fixed to vertical frame members 5. Bearings 10, in which shaft 11 of wet-out roll 7 is journalled, are slidably mounted on vertical frame members 5.

The vertical position of wet-out roll 7 is adjustable, and is regulated by hydraulic positioning cylinders 13 mounted on the top of each vertical frame member 5. In this way, the pair of wet-

out rolls

6 and 7 cooperate to control the moisture content of a web or layer of fibrous material, of a type such as mentioned above as being a suitable starting material, which is fed through the nip between the wet-out rolls. Preferably the moisture content of the layer of fibers as it is moved from the wet-out rolls is in the neighborhood of from 109 to 200 percent. (The term percent moisture," when used in this specification, refers to percentage of moisture by weight of the dry web.)

The layer of fibers moves from the nip of the wetout rolls to the fiber rearranging zone of the apparatus to effect the rearrangement of the fibers in the starting web or layer 15, to produce a rearranged fibrous web or layer 15' having a plurality of patterns of holes or other areas of low fiber density as described above. Thus the starting layer of fibers moves from the wet-out rolls to be supported on a backing means in the form of endless belt 16 (to be described in detail below), which extends around a pair of parallel rolls 17, 18 rotatably mounted adjacent opposite ends of the frame. Each of the rolls 17, 18 is mounted on a shaft 19, the ends of which are journalled in bearings 20 carried on horizontal frame members 2. Conventional driving means (not shown) are connected to either one of shafts 19.

A water pipe 21, mounted in any suitable manner, supports a pair of headers 22 above the upper reach of endless belt 16. Each header extends transversely of belt 16, and has a row of jet nozzles 23 to provide water sprays across the width of that belt.

A pair of suction boxes 24 are mounted on and extend transversely across frame members 2 between the rolls l7 and 18 which carry endless belt 16, with one of the boxes located directly beneath each row of jet nozzles 23. Each suction box is closed on all sides except for an opening 25 to which a vacuum line 26 is connected, and a slot or group of perforations 27 which extend across top wall 28 of the suction box. The top wall of each suction box is positioned adjacent the underside of the upper reach of endless belt 16.

Nonwoven fabric 15', after rearrangement but before reaching the position where endless belt 16 starts to track around roll 18, is lifted off the belt by causing it to pass upwardly and over a horizontal cylindrical doffing member 290 which extends transversely of the machine and is supported at its ends in the side frames. The fabric then passes downwardly and around through the nip between guide rolls 29b and 29c on its way to a suitable drying area (not shown). Guide rolls 29b and 29c are parallel to doffing member 290, and like it are supported at their ends in the side frame members of the machine.

Backing means. Endless belt or backing means 16, as shown in FIG. 2, has a continuous pattern of foraminous portions 30 and a discontinuous pattern of imperforate portions 31. 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 backing means, 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 backing means; 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 31 of backing means 16 has a curved top surface that rises slightly above the top surface of foraminous portions 30 of the backing means. Because of the curved top surface, central portion 32 rises above edge portions 33 of discontinuous imperforate portions 31 of the backing means. Extreme edge portions 34 are slightly rounded.

Foraminous portions 30, as shown in FIGS. 4 through 6, are formed of a coarse woven screen, preferably metal. In the embodiment shown, wires 40 running vertically in FIG. 4 are straight, while wires 41 running horizontally in that figure weave alternately over and under wires 40. Protuberances 42 are present throughout foraminous portion 30 as the topmost part of each knee" of a given strand 41 of the screen that is formed as the strand weaves over and under the strands 40 that lie perpendicular to it.

As a given strand 41 slants downward to pass under a strand 40 perpendicular to it, it crosses two other strands 41 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" 43 forms a trough, such as trough 44 in FIGS. 4 and 5, that lies between adjacent protuberances 42. The effective cross sectional shape of troughs 44, as can be best seen in FIG. (which shows a cross section of element 30 of which a plan view is given in FIG. 4), is substantially an inverted triangle.

A series of slightly deeper troughs 45 is formed between adjacent protuberances 42 extending at right angles to troughs 44. As best seen in FIG. 6, the bottom of each trough 45 is formed by portions of straight strands 40, with successive protuberances 42 on each side of the trough forming the tops of the trough. As seen in FIG. 6, the effective cross sectional shape of troughs 45 may be characterized as a shallow U-sha'pe.

As shown in FIG. 4, troughs 44 and protuberances 42 alternate in one direction across the surface of foraminous portion 30 of backing means 16. FIG. 4 also shows that troughs 45 and protuberances 42 alternate in a direction perpendicular to troughs 44. Hence a plurality of troughs and a plurality of protuberances alternate in both the longitudinal and transverse directions across the surface of foraminous portion 30 of backing means 16.

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

troughs

44 and 45, the vertical distance between the tops of protuberances 42 and the bottoms of the immediately adjacent troughs should be at least about three times, generally no more than about 30 times, and preferably about 10 times, the average diameter of the fibers in the layer of fibrous starting material. For troughs 44, this distance is the vertical distance indicated in FIG. 5 by the pair of dashed lines that pass, respectively, through the tops of protuberances 42 and the crossing points 43 that define the troughs. The vertical distance from the bottom of each trough 45 to the tops of protuberances 42, on the other hand, is somewhat larger, being shown by FIGS. 5 and 6 to be equal to the diameter of a strand 41.

In the embodiment shown, each protuberance 42 has a directional effect in one direction because of its proximity to other similar protuberances on foraminous portion 30 of the backing means, and in the other direction for the same reason and in addition because of the cross sectional shape of the protuberance. Thus, each protuberance 42 is effective in both the longitudinal and transverse directions. As an example, the protuberance 42 to which the designator line runs in the upper left hand comer of FIG. 4, through cooperation with the protuberance 42 to which the designator line runs in the left central part of the bottom of that same figure, is effective as a protuberance that defines one wall of trough 44 running vertically down the middle of the figure. At the same time, the first named protuberance 42, through copperation with protuberance 42 to which the designator line runs in the upper right hand part of FIG. 4, is effective as a protuberance that defines one wall of trough 45 running horizontally across the middle of the figure. In addition, the cross sectional shape of each protuberance 42 (as best seen in FIGS. 4 and 6) 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. 4, i.e., on the side walls of each trough 45.

At the point of closest spacing of each pair of immediately adjacent barrier regions or discontinuous imperforate portions 31 of backing means 16, each continuous deflecting region or interconnecting foraminous portion 30 is wide enough to include at least one dispersal point or protuberance 42 and a fiber accumulating zone or

trough

44 or 45 on each side thereof. In the embodiment of FIGS. 2 and 3, each pair of imperforate portions 31 include between them at their point of closest spacing about five protuberances 42 and their associated troughs or fiber accumulating zones.

Three portions of rearranging fluid. The directions the projected streams of rearranging fluid take as they move into and through the fibrous web determine the types of forces applied to the fibers and, in turn, the extent or rearrangement of the fibers. Since the directions the streams of rearranging fluid take as thy move through the fibrous layer are determined in part by the pattern of the solid wires that make up foraminous portions 30 of backing means 16, and in particular the pattern of protuberances and troughs distributed across the surface of foraminous portions 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.

As is seen from FIG. 4, first portions of the streams of rearranging fluid that have been projected into the fibrous web strike the wires of woven screen 30, at protuberances 42 or at other portions of the wire, and are deflected sidewise before they pass out of the rearranging zone through openings 46. The streams of rearranging fluid that strike protuberance 42 in the upper left hand part of FIG. 4, for example, leave the fiber rearranging zone through

openings

46a, 46b, 46c and 46d in the respective sectors or quadrants of the area surrounding that protuberance.

FIGS. 2 and 3 show that second portions of the rearranging fluid projected into the layer of starting material strike discontinuous imperforate portions 31 of backing means 16, and are deflected sidewise into the areas above foraminous portions 30, where they are mingled with the first portions of rearranging fluid and are passed out of the rearranging zone though openings 46.

Third portions of the rearranging fluid projected into the fibrous web pass directly through openings 46 in foraminous backing portion 30, without being deflected either by protuberances 42 or imperforate portions 31.

Flow of first portions of rearranging fluid through deflecting regions. The dotted lines in FIGS. 5 and 6 give a schematic showing of the path followed by a stream of rearranging fluid 47 that is directed into the layer of fibrous starting material, in a direction perpendicular to that layer, to strike protuberance 42 in the upper left hand corner of FIG. 4. As is seen, the stream of fluid is deflected downwardly and outwardly away from its perpendicular direction of entry into the fiber rearranging zone, and then moves out of the rearranging zone through the openings between

wires

40 and 41.

The flow of streams of rearranging fluid after being deflected sidewise upon striking protuberances 42 of foraminous portions 30 of backing means 16 produces sets of counteracting components of force that act in the plane of the web until the fluid passes out through the foramina in portions 30. The counteracting fluid forces in each of these sets work in conjunction with one another to rearrange fiber segments into yarn-like I bundles positioned in

troughs

44 and 45 of portion 30 of backing means 16. Some of these yarnlike bundles of fiber segments lie in fiber accumulating zones in peripheral portions of foraminous portions 30 adjacent discontinuous imperforate portions 31 of backing means 16, while some lie in troughs or fiber accumulating zones between one protuberance 42 and another protuberance that is parallel and immediately adjacent to it.

When the layer of fibrous starting material is first positioned in that part of the fiber rearranging zone located above foraminous portion 30 of backing means 16, and before a rearranging fluid has been directed into the layer, the fibrous web of course lies upon the tops of protuberances 42. After fiber arrangement has proceeded under the impact of the streams of rearranging fluid, the fibers are moved down the sloping sides of protuberances 42 into

troughs

44 and 45. At this juncture, the layer of rearranged fibers that comprises the nonwoven fabric ordinarily lies largely, if not altogether, below the tops of protuberances 42.

FIGS. 7 and 8 provide schematic representations of the flow of streams of rearranging fluid 47 that has been described in connection with FIGS. 4 through 6. As explained above, in the practice of this invention the layer of fibrous starting material is supported in a fiber rearranging zone in which fiber movement in directions parallel to the plane of the fibrous material is permitted in response to applied fluid forces. The fiber rearranging zone has an entry side and an exit side, and is subdivided into barrier regions 31 arranged in a discontinuous pattern and deflecting regions 30 that are continuous and lie between and interconnect the barrier regions. FIGS. 7 and 8 depict a part of a deflecting region 30.

In FIGS. 7 and 8, the fiber rearranging zone is indicated as being defined by foraminous portion 30 of backing means 16. Streams of rearranging fluid are projected into the fibrous layer as thus supported, in a direction perpendicular to said layer, substantially uniformly and continuously across the surface of the layer. In FIGS. 7 and 8, streams 47 represent first portions of those rearranging streams that take a particular path through the fiber rearranging zone.

First portions 47 of the rearranging fluid are passed through initial part 48 of the rearranging zone, as the fibrous layer lies in the zone. The streams of fluid 47 are passed toward dispersal points 42 lying adjacent the exit side of the rearranging zone, two of which dispersal points are shown for illustrative purposes in FIGS. 7 and 8.

At each dispersal point 42, streams of rearranging fluid 47 are deflected diagonally and downwardly away from the perpendicular direction of entry of streams 47 into the fibrous starting material, into the area immediately surrounding each dispersal point 42. In FIGS. 7 and 8, fluid stream 47 that is directed toward dispersal point 42 in the upper left hand portion of FIG. 8 is directed upon deflection into sectors or

quadrants

46a, 46b, 46c and 46d of the area surrounding that dispersal point.

A few of the fiber segments of the fibrous starting material that lie in deflecting region 30 of the rearranging zone remain, after treatment with streams of rearranging fluid, in substantially the positions they occupied by random chance in the starting layer. Most of the fiber segments lying in the deflecting region, however, are moved by the deflection of rearranging fluid just described into the area surrounding that dispersal point 42 at which each fluid stream 47 was deflected.

The fiber segments moved by deflected streams of rearranging fluid 47 are positioned in yarn-like bundles of closely associated and substantially parallel fiber segments in

fiber accumulating zones

44 and 45 in the area surrounding each dispersal point 42. As an example, fiber segments that are moved so that they extend between areas 46a and 46b of FIG. 8 are positioned there in fiber accumulating zone 44 which extends vertically in that figure between the two dispersal points 42, lying adjacent each other, that are shown in FIG. 8. Likewise, fiber segments that are moved so that they extend between areas 461; and 460 are positioned in fiber accumulating zone 45 which extends horizontally in FIG. 8, and so on.

Fiber accumulating zones

44 and 45 correspond to

troughs

44 and 45 shown in FIGS. 4 through 6. The yarn-like bundles of fiber segments positioned in the fiber accumulating zones form a pattern of yarn-like bundles corresponding to the pattern of the fiber accumulating zones, which in turn is determined, among other things, by the position of the various dispersal points 42 throughout the fiber rearranging zone.

The deflected portions of rearranging fluid 47 are then passed out of the fiber rearranging zone through spaced exits such as 46a through 46d, and similar exit areas, in FIGS. 7 and 8. At the same time, other portions of rearranging fluid that were projected into the layer of fibrous starting material, for example those portions entering the entry zone in direct registry with exit 4612, are moved directly to and through the exits on the exit side of the rearranging zone without passing through a dispersal point 42 to be deflected from the perpendicular direction at which they entered the fibrous starting layer.

In the embodiment shown diagrammatically in FIGS. 4 through 6 and in the schematic representations of FIGS. 7 and 8, the spaced exits on the exit side of the rearranging zone are located in the fiber accumulating zones.

Flow of second portions of rearranging fluid through barrier regions. The directions taken by the second portions of the streams of rearranging fluid, which are projected into the fibrous starting material lying in the barrier regions of the fiber rearranging zone, are of course also important. The directions those portions of the rearranging fluid take as they move into and through the fibrous web determine the types of forces applied to the fibers that lie in the barrier regions, and, in turn, help determine the extent of rearrangement of the fibers throughout the barrier regions, and thus help determine the pattern of holes or other areas of low fiber density in the resultant fabric.

The second portions of the rearranging fluid which are projected into a barrier region for example, each part of the rearranging zone overlying an area 31 where backing means 16 is imperforate are deflected sidewise out of the barrier region into adjacent deflecting regions. Thus, such streams strike imperforate portions 31 in FIG. 2, to be deflected sidewise and effect movement of fiber segments transverse to the direction of travel of the projected streams.

This fluid flow pushes fiber segments off imperforate portions 31 to position the segments in the above mentioned yam-like bundles of fiber segments in areas adjacent the periphery of those imperforate portions, and elsewhere in the deflecting regions overlying foraminous portions 30 of the backing means. 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.

' Flow of third portions of rearranging fluid through deflecting regions. As indicated above, the passage of rearranging fluid through the fiber rearranging zone and the layer of fibrous starting material supported therein is completed by the flow of third portions of the fluid through the deflecting regions of the rearranging zone.

As is seen from FIG. 4, third portions of rearranging fluid that are projected into the fibrous web in a direction perpendicular to the plane of the web (i.e., the plane of the drawing in that figure) pass through the fibrous layer and, after being intermingled with the first and second portions of fluid discussed above, pass directly out of the fiber rearranging zone through spaced exits such as

openings

46a, 46b, 46c and 46d. These third portions of fluid do not strike protuberances 42 to be deflected sidewise, and thus do not pass through any dispersal points in the deflecting region. Likewise, since they do not enter the barrier regions of the fiber rearranging zone, they do not strike imperforate portions 31 of backing means 16.

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 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 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 usuable fabric.

The following is an illustrative example of the use of the method and apparatus of this invention to produce a patterned nonwoven fabric:

EXAMPLE In apparatus as illustrated in FIG. 1, a web 15 of loosely assembled fibers, such as may be obtained by carding, is fed between wet-

out rolls

6 and 7, and from there onto endless backing means 16. The web weight is about 400 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 1% denier.

Foraminous portions 30 of backing means 16 are comprised of a woven metal screen of approximately 8 X 16 mesh or substantially 128 openings per square inch. The top of each protuberance 42 on the backing means rises above the bottoms of troughs 44 immediately adjacent to it by approximately 0.018 inch, or about 12 times the 0.0015 inch average diameter of the 1% denier fibers of the starting material. They rise approximately 0.026 inch above the bottoms of troughs 45, or about 18 times the average fiber diameter.

The distance measured in one direction across foraminous portions 30 of backing means 16 between the top of one protuberance 42 and the top of the protuberance immediately adjacent to it is about 0.063 inch, and in the other direction about 0.125 inch. These distances are equal, respectively, to approximately 42 and 84 times the average diameter of the fibers of the fibrous starting material.

Discontinuous imperforate portions 311 of backing means 16 are smooth round metal members of a diameter of approximately one-fourth inch and having a cross sectional shape similar to that shown in FIG. 3. They are distributed over the area of backing means 16 in a diamond pattern, with a space of approximately threesixteenths inch from each portion 31 to the nearest other portion 31 in a diagonal direction. Central portions 32 of elements 31 rise about 0.012 inch above the plane of the top surface of continuous foraminous portions 30 of the backing means, and edge portions 33 rise about 0.010 inch above that plane.

The distances between one fiber accumulating zone or trough and the zone or trough immediately adjacent and parallel to it are the same, in the two directions across foraminous portions 30, as the distances between adjacent protuberances. Hence the 0.25 inch width of each imperforate portion 31 is between about two and about four times the distance between trough centers.

In the practice of this invention, water is projected from nozzles 23 against fibrous web in a direction perpendicular to the plane of the web, to pass through the fibrous layer and through backing means 16.

After given portions of backing means 16 and fibrous web 15 pass through the rearranging zone, in which streams of water are directed against them as just described, the movement of the upper reach of endless belt 16 (to the right as seen in FIG. ll) brings the rearranged fabric to doffer roll 29a and guide rolls 29b and 290, from whence 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. 9, which has a plurality of patterns of holes or other areas of low fiber density that alternate and extend throughout the fabric, is produced.

Nonwoven fabric 50 of FIG. 9 is shown with an original enlargement of five times in the photomicrograph of FIG. 10. As seen in the latter figure, fabric 50 contains a first pattern of areas of low fiber density 51, each of which overlies a discontinuous imperforate portion 31 of backing means 16. Each area 51 is defined by yarn-like bundles 52 of closely associated and substantially parallel fiber segments, which lie in fiber accumulating zones located in the peripheral portions of the deflecting regions of the fiber rearranging zones, as for example in the peripheral portions of each foraminous portion 30 where it abuts the perimeter of discontinuous imperforate portions 31. Each area of low fiber density 51 contains a few scattered fiber segments that bridge across the area.

In addition, nonwoven fabric 50 contains a second pattern of areas of low fiber density in the form of holes 53, arranged in accordance with the pattern of arrangement of protuberances 42 of foraminous portions 30 of backing means 16. Each of these areas 53 is defined by yam-like bundles 54 of closely associated and substantially parallel fiber segments, which lie in fiber accumulating zones located between immediately adjacent dispersal points, as for example immediately adjacent protuberances $2 in foraminous portions 30 of backing means 16. In the fabric shown, each hole 53 is substantially free of any fiber segments.

Each area of low fiber density 51 appears from FIG. 10 to be approximately 40 times the size of each area of low fiber density 53, or alittle bit larger. This is consistent with the relative size of discontinuous imperforate portions 31 and protuberances 42 of foraminous portions 30 that are included in the apparatus with which the fabric of FIGS. 9 and 10 was made.

Each pair of immediately adjacent large areas of low fiber density 51 is separated by at least one of the smaller holes, such as those designated 53' in FIG. 10. To produce this result, the width of interconnecting foraminous portions 30 of backing means 16 at their narrowest parts (or, in other words, the closest diagonal spacing between imperforate portions 31 of the backing means, which is about 3/16 inch or 0.188 inch) is sufficient to include at all points around the perimeter of each imperforate portion 30 at least one protuberance 42 and in most parts of the rearranging zone two protuberances 42 with associated fiber accumulating zones or

troughs

44 and 45.

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

I claim:

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 which are imperforate and portions which are foraminous, said imperforate portions being discontinuous and said foraminous portions being continuous and interconnecting the discontinuous imperforate portions, said continuous foraminous portions comprising at least 10 percent of the total area of the backing means, said foraminous portions having a plurality of protuberances and troughs alternating across the surface thereof in both the longitudinal and transverse directions, the tops of said protuberances rising above the bottoms of said troughs by a distance of at least .005 inch, the width of each trough being at least 0.025 inch, each of said discontinuous imperforate protions extending along the surface of the backing means a distance at least about twice the horizontal distance from the center of one of said troughs to the center of the trough immediately adjacent and parallel to it, and each pair of immediately adjacent discontinuous imperforate portions spanning between them at least one of said protuberances and at least part of one of said troughs on each side of said one protuberance; means for moving said backing means, with a layer of fibrous starting material positioned thereon, through a rearranging zone; means for projecting streams of rearranging fluid against said fibrous layer substantially uniformly and continuously across the surface thereof to pass through said layer, some of said fluid streams striking said imperforate portions of the backing means and other of said fluid streams striking said protuberances on the backing means, all to be deflected thereby in sidewise directions and all of said fluid streams, together with other streams of fluid that do not strike the backing means, passing through and beyond said foraminous portions of the backing means; and means to apply vacuum on the side of said backing means opposite to said fibrous layer to assist in moving all said rearranging fluid through the fibrous layer and in rearranging the fibers of said layer.

2. The apparatus of claim 1 in which each of said discontinuous imperforate portions of the backing means rises above the plane of the tops of said foraminous portions of the backing means by a distance of at least 1/64 inch, with the central portion of said discontinuous portion rising higher than the edge portions thereof.

3. The apparatus of claim 1 in which the width of each of said discontinuous imperforate portions of the backing means, measured in each direction, is equal to at least about three times the horizontal distance from the center of one of said troughs to the center of the trough immediately adjacent and parallel to it.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,750,236 Dated August 7, 973,

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

r. Abstract: Next to last line insert "the" before .1 protuberances.

In Column 4, line 3 L "arrangement" should. read "rearrangement" In Column 6, line 1 "polyanides" should read "polyamides" in Column 7, line 35 "with" should read "With" In Column 7, line 41. "material. or" should read "material,

In Column 9, line 57 "the" should. read "the" In colunn 10, line 21 "fibe" should read "five" n In ooiumn 1o, liheAg delete "109" "In Column 13, line l2"thy" should be "they" In Column 1? line 38- "though" --Y- should read "through" In Columnlfl, line 10 "arrangement" should read "rearrangement" 1 Signed and .seal ed this 15th day of October 1974.

(SEAL) Attest:

'nccoy GIBSON, JR. 1-

l L 0. MARSHALL DANN e Attesting Officer Commissioner of Patents