US3392078A - Nonwoven fabric and method of making the same - Google Patents

Description

D. DUHL 3,392,078

NONWOVEN FABRIC AND METHOD OF MAKING THE SAME July 9, 1968 3 Sheets-Sheet 1 Filed 0st. 5, 1964 INVENTOR. DANIEL DUHL BY i vwg... -1

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D. DUHL 3,392,078

NONWOVEN FABRIC AND METHOD OF MAKING THE SAME 3 Sheets-Sheet 2 July 9. 1968 Filed Oct. 1964 n wt M NL A:

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his ATTORNEYS D. DUHL July 9, 1968 NONWOVEN FABRIC AND METHGI) OF MAKING THE SAME 5 Sheets-Sheet 3 Filed Oct. 5, 1964 FIG. 5

INVENTOR.

DANIEL DUHL BY $----L --5 1H,

hi8 ATTORNEYS United States Patent "ice ABSTRACT OF THE DISCLOSURE A corduroy fabric is described comprising a stitchbonded, nonwoven fabric having closely spaced parallel chains of stitching thread with parallel ridges of fabric intermediate the chains, and a fiber flock preferentially aflixed to the ridges. A method for making this fabric is also disclosed.

This invention relates to a novel nonwoven corduroy fabric and to a method of obtaining the fabric.

Conventional corduroy fabrics are made by weaving an extremely high number of filling threads per inch floating on the face of the fabric and only interwoven at specific warp threads to create longitudinal strips of filling floats. These floats are then cut with knives and brushed up to create the corduroy effect. The special weaving techniques, and the cutting operations add to the expense of making these fabrics. In addition, the rate of producing woven fabric is directly related to the number of filling threads per inch. Because of the extremely high number thereof required for corduroy fabric, the rate of production of the fabric is relatively low.

As an additional disadvantage, preparation of corduroy fabrics by weaving techniques requires a tight weave to insure that the fibers comprising the floats are securely bound to the fabric. This fact presents considerable problems in preparing a corduroy with stretch and recovery characteristics with conventional stretch or crimped yarns.

Extensive use is being found in the apparel industry for thin sheets of elastomeric foam made either from natural rubber or from synthetic plastic materials. Foamed polyurethane, for example, is used in cold weather garments where it is generally combined with layers of conventional fabrics, the latter forming inner and outer protective coverings for the sheet of foam. In this type of structure, the fabric layers have been attached to the foam by loose and spaced-apart quilting stitches.

Considerable interest has also been shown in bonded r fabrics, where a layer of a conventional fabric is bonded to a thin sheet of elastomeric foam to form a composite fabric having the limited extensibility and hard exterior surface of the conventional fabric and the insulating properties of the foam layer. Products of this type wherein the conventional fabric is a conventional corduroy are known.

It is an object of this invention to provide a novel nonwoven corduroy fabric.

It is another object of this invention to provide a nonwoven fabric which utilizes the stretch characteristics of the elastomeric foam sheets, which limits the extensibility of the foam sheet at a point short of rupture thereof, and which has an exterior wearing surface of adherent fibers 6 providing a corduroy effect.

It is another object of this invention to provide a novel method whereby these fabrics may be prepared in an inexpensive manner.

It has now been found that a corduroy fabric may be made in a simple and inexpensive manner by first providing a stitch-bonded base fabric, one surface of which 3,392,978 Patented July 9, 1968 has closely spaced parallel loop chains of stitching thread, with ridges of fabric intermediate the rows, and by thereafter securing a fiber flock preferentially to these ridges. In one embodiment of the invention, the stitch-bonded base fabric is a fiber batting which is stitch-bonded with a thread applied through the batting as a chain stitch, half tricot stitch or a combined tricot and chain stitch.

In the preferred embodiment according to this invention, it has been found that a corduroy fabric with stretch and recovery characteristics may be made by providing a base fabric comprising a durable foam stretch fabric, one surface of which has closely spaced parallel loop chains of stitching thread with intermediate fabric ridges, the durable foam stretch fabric being prepared according to a method described in my copending application Ser. No. 361,619, filed Apr. 20, 1964, now US. Patent No. 3,274,806.

An adhesive is then applied to the surface of the stitchbonded base fabric which has parallel rows of chain stitches with intermediate ridges, a fine dispersion of fiber flock is placed onto the adhesive coated surface, excess nonadhering flock is removed, and the adhesive is dried or cured. When this process is conducted in a conventional flocking device substantial amounts of flock fibers adhere to the ridges intermediate the rows of chain stitches, but only insignificant amounts of flock adhere to the stitching threads. The resulting fabric has uniform, parallel ridges of fiber, and closely resembles a conventional corduroy fabric in appearance.

In the preferred embodiment utilizing a durable foam stretch fabric as the base, the base fabric is preferably sized with a suitable water-soluble gum prior to the flocking operation to minimize web flutter during the flocking step. The size may be removed from the fabric, if desired, by passing the flocked fabric through an aqueous scouring bath after the adhesive has been cured.

The present invention contemplates the preparation of at least three distinct types of corduroy fabric. A nonstretch fabric is provided when the stitch-bonded base fabric is of the type wherein the fabric layer pierced by the bonding stitches comprises nonwoven fibers such as a fiber batting. The primary considerations in preparing the base fabric of this type is that the stitching thread be applied so that parallel rows of chain stitches appear on one surface of the fabric, and that the stitch be applied under tension sufficient to form intermediate ridges of the fibers between the parallel rows of stitches.

In addition to the nonstretch corduroy fabric, one-way stretch and two-way stretch fabrics may be obtained by using the durable foam stretch fabrics having these respective characteristics as the base fabric. These stretch fabrics are described in my copending application identified above.

The durable foam stretch fabric is prepared by first providing a sheet of elastomeric foam, the elastomer being a foam rubber or other foamed or cellular synthetic material such as polymers of butadiene or of butadiene and styrene, reaction products of polysulfide salts and polyhalides, polymers formed from halogenated unsaturated hydrocarbons, isobutylene polymers, polymeric vinyl halides, polyamides, polyesters and polyureas. These are also suitable for use in the present invention. A preferred material is polyurethane foam.

The sheets of elastomeric foam may be used in thicknesses varying from about of 'an inch to /2 inch or more, depending upon the end use to which the fabric is to be put. One preferred thickness for polyurethane foam used according to this invention is of an inch. Continuous sheets of elastomer are available in varying widths. A conventional width for polyurethane foam is 68 inches, and other widths range from to 78 inches. Selection of an appropriate width will depend upon the dimensions of the apparatus used to make the fabric.

The sheet of elastomeric foam is formed into a durable foam stretch fabric by knitting into the sheet an extensionlimiting yarn system comprising a plurality of closely spaced rows of thread, each row being knitted through the sheet to form a row of interconnected loops on the opposite surface thereof. In this manner, the elastomeric foam in effect is encased within the yarn system.

The extension-limiting yarn system is formed from a yarn or thread which itself is substantially non-extensible. The yarn system may be provided by rows of thread in the form of a double thread chain stitch but in that event, a transverse reinforcing yarn must be used to prevent the foam sheet from breaking when the fabric is stretched in a transverse direction. The preferred extension-limiting yarn system in the durable foam stretch fabric used in accordance with this invention is provided by rows of thread knitted through the foam sheet in the form of a full tricot stitch, a half tricot stitch, or a combination chain and tricot stitch. The most preferred extension-limiting yarn system is a half tricot stitch.

The half tricot s itch forms closely spaced rows of loops on one surface of the elastomeric sheet, the thread passing through the sheet and forming a zigzag line on the other surface of the sheet. The zigzag line represents a single 1 x 1 warp, in which two ends lap obliquely in opposite directions. The chains of loops and the courses of loop chains are thereby joined with each other.

The fabric construction thus provided utilizes the extensibility of the elastomeric foam sheet, but provides a limit of extension at a point prior to rupture of the elastomeric sheet. In order to exceed this limit, the yarn system must be broken. At the same time, the yarn system provides a protective layer of thread on both sides of the sheet. The sheet of foam is integrated with the thread of the yarn system to produce a single ply coherent product having essentially the hand or drape of a knitted fabric and retaining the insulating properties of the foam. As an additional advantage, where thermoplastic yarns, such as nylon, are used as the thread with sheets of a foam, such as polyurethane, the resulting fabric structure is moldable under the influence of heat and pressure to form a molded foam product. Molding of the polyurethane foam sheet itself cannot be accomplished.

A preferred fabric according to this invention is obtained where the extension-limiting yarn system is applied to the sheet of elastomeric foam while the sheet is in a stretched condition. This is accomplished by stretching a continuous sheet of the elastomeric foam in a linear direction, a preferred degree of stretch being about The extension-limiting yarn system is knitted into the stretched sheet, the closely spaced rows being oriented parallel to the direction in which the sheet is stretched. The sheet is then allowed to contract in recovery from its stretched condition. The limit of extensibility in the linear direction is thus fixed at approximately 40%, where a tricot yarn system is applied. Because of the interconnecting warp lap segments between adjacent rows of the tricot yarn system, an extension limit is imposed on stretch of the fabric in the transverse direction. The resulting fabric has stretch characteristics in two directions, and resembles a two-way stretch fabric.

While the preferred degree of stretch applied to the elastomeric foam in a linear direction is 40%, it is recognized that this is merely representative and can be varied in accordance with the requirements of the breaking point of the sheet of elastomeric foam used. This procedure also provides a means whereby the degree of stretch imparted to the final fabric may be controlled.

The thread used in the extension-limiting yarn system of the fabric structure of this invention may be nylon, rayon, both viscose and acetate, cotton, wool, linen, dacron, and the like. It may be monofila'ment or multifilament, and may range in denier from 15 to 1,000, or more.

In addition, it must have a breaking strength in excess of that of the foam sheet. A preferred yarn is a nylon yarn of about denier. Another preferred yarn is 300 denier acetate rayon.

In practicing this invention, consideration must be made to both the stitch length and the number of wales of chains of loops employed in the extension-limiting yarn system. The latter variable is more conveniently referred to as gauge, the gauge number being the same as the number of wales of chains of loops per inch. It has been found that a stitch length shorter than about 1.5 millimeters causes so many perforations to be made in the elastomeric foam sheet that the strength thereof is severely reduced, and in extreme cases, the elastomeric foam sheet is actually severed to form longitudinal strips. A similar problem is encountered where more than about 18 wales per inch are applied (18 gauge), causing severed transverse strips of foam.

When the sheet of elastomeric foam alone is incorporated within the extension-limiting yarn system, a stitch length greater than about 2.0 millimeters provides an excessive amount of extension-limiting yarn to the fabric, thus increasing the extensibility of the fabric beyond the breaking point of the foam sheet Where about 18 wales to the inch are used. Where about 14 wales to the inch are used, a stitch length of no more than about 1.5 millimeters can be employed. The longer stitch lengths, i.e., those in excess of about 2.0 millimeters with 18 gauge, and those in excess of about 1.5 millimeters with 14 gauge, permit the fabric to be stretched beyond the tear limit of the foam in the transverse direction. Where a wider Wale corduroy is desired, a coarser gauge may be used, providing extensibility of fabric in a transverse direction is limited by incorporation of a transverse filling yarn.

The above limits of wales per inch, and of stitch length have been determined with respect to polyurethane foam having a thickness of of an inch and with 100 denier nylon and 15/1 cotton yarns. The limits will vary, depending upon the strength and other properties of the specific elastomeric foam sheet employed, and where the yarns used are of a different nature. The various considerations given will enable one skilled in the art to readily determine the limits for a given combination of materials.

The fabrics of this invention may be made in any apparatus used by those skilled in the art to apply closely spaced parallel rows of chain stitching, lock stitching or tricot stitching to a continuous web. One preferred apparatus which can be used in preparing the fabrics of this invention is that disclosed in the US. Patent No. 3,030,786 to H. Mauersberger. Another suitable apparatus is the Arachne unit, made by Kovo of Prague, Czechoslovakia.

An important feature of this invention is the requirement that one side of the stitch-bonded fabric carries the stitching yarn system in the form of parallel chains of loops. Secondly, the yarn system must be applied so that the yarn system and elastomeric sheet or fiber batting are maintained under a positive tension, the amount of tension being suflicient to form parallel ridges of foam or fiber on the surface bearing the parallel chains of loops, intermediate the rows of chains. Both the stitch length and tightness of stitch influence the width and height of the ridges, and may be varied for the effect desired.

In an additional embodiment of this invention, relatively coarse warp yarn may be laid in, in random arrangement, under the stitches on the side of the fabric opposite that having the parallel rows of chain stitches. This makes larger ridges, and when flocked, shows a random stripe corduroy effect.

As instructed above, it is preferred that the durable foam stretch fabric be sized, and any suitable watersoluble size may be used for this purpose. This operation is conveniently performed in a padder or sizing U machine, using a water-soluble gum. The padder includes a pin tenter frame, on which the sized fabric is dried. After drying the sized fabric should be stiff, but flexible. Care should be taken that an excessive amount of size is not used, so that the subsequently applied adhesive finds sufficient fabric surface for holding the flock.

A water-soluble size found suitable for use according to this invention is a carboxylated acrylic polymer, sold under the trade name Acrysol, by Rohm and Haas. Good results have been obtained using this material in 20% aqueous solution, followed by drying the sized fabric at 300 F.

The adhesive used in accordance with this invention should be liquid, and of a suitable viscosity. It should not penetrate the base fabric to a substantial extent after application, and on the other hand, should not be so viscous as to be difficult to apply. Furthermore, it must, after curing, be sufficiently flexible to withstand stretching of the fabric without weakening and becoming detached therefrom. Also, it should be able to withstand dry cleaning and laundering operations Without deterioration. One suitable adhesive has been found to be a water base acrylic resin adhesive of 9 to M cps. viscosity. Other adhesives with these desirable characteristics are known to those skilled in the art. The specific combination of the carboxylated acrylic polymer sizing described above and a water base acrylic resin adhesive has been found to give exceptionally fine results, and the flock applied with this combination of ingredients has exceptional resistance to abrasion.

Conventional present-day flocking processes, such as those used to make a velvet fabric, provide fabrics which have very limited porosity, and do not breathe. This disadvantageous characteristic is usually caused 'by the continuous film that is formed by the adhesive, which must of necessity cover the entire fabric surface to insure a uniform adherent flock coating.

In accordance with a preferred embodiment of this invention, care is taken that the adhesive film is discontinuous, and is broken at least at the points Where the bonding stitch pierces the fiber batting or foam layer. Important factors in this regard are the viscosity of the adhesive, the amount applied, the distance between the top of the ridges and the chains of bonding stitches, and the extent to which the base fabric is deformed or compressed during the adhesive application step. It is preferred that these factors be controlled so as to apply an adhesive coating only to the exposed fiber or foam forming the ridge, and so that little or no adhesive is applied to the stitching threads. This procedure not only insure-s a definite corduroy pattern of flock on the fabric surface, but at the same time, leaves a substantial portion of the fabric surface without an adhesive film, thus insuring porosity.

The flock used may be cotton, rayon, nylon or other desired materials. Suitable materials include cut and predyed nylon and cotton waste fibers having random dimensions ranging from dust to 0.03 inch. Exceptionally fine results are obtained using precision cut nylon tow, the product being a high pile velvet corduroy. Tow cut to lengths ranging from 0.03 inch to 0.20 inch provides good results.

The flocking may be carried out by conventional procedures, such as mechanical or electrostatic flocking. Mechanical flocking is generally preferred.

Where durable foam stretch fabric is processed in a mechanical flocker, it has been noted that the beater beneath the fabric causes undesirable take up of the web, because of the increased resistance and extensibility of the polyurethane foam. The take up, in many instances resulted in a decrease in web width of one third of its dimension. This, in turn, gave unacceptable and nonuniform coating of flock.

It has been found that this difficulty can be overcome by running the sized foam fabric through the flocking machine with a carrier web of material which has the same width as the fabric, but is substantially nonextensible, and has a relatively smooth surface. A suitable material for this purpose is kraft paper. The carrier web must be able to transmit vibrations received from the beater mechanism.

After flocking, the fabric is carried to a curing oven, where the adhesive is set. The curing conditions will be varied according to the needs of the adhesive. With the above-mentioned water base acrylic adhesive, an oven temperature of 260 F. for minutes is used.

After curing, the fabric may be scoured to remove the water-soluble size, and the fabric again dried in any suitable manner.

The invention will be further described with reference to the accompanying drawings in which:

FIGURE 1 shows an enlarged perspective view, partly in section, of the fabric of the invention;

FIGURE 2 is a cross-section taken through the structure shown in FIGURE 1;

FIGURE 3 is a fiow diagram showing the process of this invention;

FIGURE 4 is a diagram showing a combination chain and tricot stitch structure, an alternate embodiment of this invention; and

FIGURE 5 shows, in section, an embodiment having a random arrangement of laid-in coarse warp yarn.

Referring to FIGURES 1 and 2, one embodiment of a durable foam stretch fabric is described comprising a sheet of polyurethane foam 10, to which has been applied an extension-limiting yarn system using an apparatus as described in the Mauersberger patent, US No. 3,030,786. The yarn system comprises threads 11 and 12 which are passed through sheet 10 to alternatively form the loops of chain 13. In the view given, each of threads 11 and 12 forms a zigzag path on the lower surface of the foam sheet 10 and parallel to the chain 13 on the upper side of the sheet 10 in the manner of a half tricot stitch. This structure is one having a one-way stretch. The extensionlimiting yarn system was applied while sheet 10 was in a substantially relaxed condition. The structure is therefore only slightly extensible in the direction of the parallel chains 13, but is extensible to the limits imposed by the interaction of the threads 11 and 12 with chains 13 in the direction perpendicular to the direction of travel of chains 13.

In the embodiment shown in FIGURE 1, the distance 14 between stitches is the stitch length; the optimum length for the embodiment shown is 1.5 millimeters. The distance 15 between wales of loop chains is governed by the gauge of the machine. A preferred value is 14 gauge, which means that 14 wales of loops per inch are applied to the foam sheet 10.

Referring again to FIGURES 1 and 2, the yarn system comprising threads 11 and 12 is applied to foam sheet 10 under a positive tension suflicient to cause the formation of parallel ridges 18 between each of the parallel loop chains 13, and of depressions 19 carrying the loop chains 13. Fiber flock 16 is attached to the foam sheet 10 through an adhesive layer 17. A relatively thick accumulation of flock 16 is provided on the ridges of foam 18 while little or no fiber fiock 16 is provided in the depressions 19, thus providing a corduroy effect on the surface of the fabric.

While FIGURES l and 2 describe a preferred embodiment of the invention, other embodiments within the scope of the invention may be obtained by suitable modification, following the considerations set forth above in the specification. For example, a two-way stretch fabric may be provided by applying the extension-limiting yarn system comprising threads 11 and 12 to a foam sheet 10 while the sheet 10 is in a stretched condition. A sheet of polyurethane foam having a thickness of of an inch may be stretched approximately 40% prior to the stitching operation, so that, on relaxing, the distance length 14 is approximately one-half the 1.5 millimeters described above as optimum for the one-Way stretch embodiment.

Similarly, a nonstretchable, nonwoven corduroy fabric is provided by substituting a fiber batting for the foam sheet of FIGURES l and 2.

FIGURE 3 is a flow diagram describing the process of this invention. For convenience, the process will be described in terms of a durable foam stretch fabric as the base fabric. Referring to FIGURE 3, a durable foam fabric 20, positioned so that the surface bearing the ridges 18 and parallel loop chains 13 (FIGURES 1 and 2) are presented as the upper surface, is positively fed from storage roll 21 to a conventional padder 22. In the padder 22, the fabric is sized with an aqueous solution of a water-soluble gum size and dried on pin tenter frames. A suitable sizing solution is a 20% aqueous solution of a carboxylated acrylic polymer sold under the trade name Acrysol by Rohm and Haas. A suitable drying temperature with this sizing material is 300 F. After sizing in padder 22, the fabric may be rerolled on a storage roll for future processing.

After sizing, the fabric 20 is fed to a reverse roller coater 23, where a thin coating of an adhesive is applied to the upper surface of the fabric bearing the ridges 18. A suitable adhesive is a water 'base acrylic adhesive having a viscosity of from 9 to 10M cps. It is preferred that the coater 23 be adjusted so that adhesive is wiped on to the ridges 18 of the fabric 20, and little or no adhesive is applied to the depressions 19 and the loop chains 13 (FIG- URES 1 and 2). After the application of the adhesive in coater 23, the fabric travels into a flocking box 24, where a fiber flock is dropped on to the adhesive coated surface of the fabric. A web of kraft paper 26 of the same width as the fabric is run through the flocking box beneath the fabric at the same speed. The paper web 26 serves e as a liner which prevents direct contact between the beater bars 27 and the fabric 20, which event causes an accumulative take-up, stretching or pulling of the fabric web 20 beyond the intended speed.

The kraft paper web 26 is rewound on storage roll 27 immediately on leaving the flocking box 24 and may be reused. The kraft Web can, of course, be replaced by any other suitable web and it may be in the form of an endless belt, thus avoiding the nuisance of changing rolls of paper.

The beater bars 27 beneath the fabric and paper webs vibrate the fabric in the flocking box so as to obtain an even distribution of the flock on the adhesive covered surface of the fabric. The vibration also serves to imbed the flock in the adhesive coating.

Upon leaving the flocking box 24, the fabric is carried through a vacuum box 28 which removes excess and nonadherent flock. The fabric then continues into a loop dryer 29. The temperature at which the dryer is operated will depend upon the nature of the flock and the characteristics of the adhesive. If the temperature is too high, damage to the flock or fabric 20 may occur. Too low a temperature will unduly prolong the curing step. Where a water base acrylic adhesive is used, a preferred drying temperature is 260 F., and the resident time in the dryer is about 45 minutes. The drying operaiton causes drying and curing of the adhesive.

After completion of the drying step, the fabric may be subjected to additional vacuum as at vacuum box 34 for removal of residual nonadhering flock, and is ready for storage and subsequent use in the making of garments, etc. If removal of some or all of the sizing is desired, the fabric may be carried to a scouring tub as shown at 30. After scouring, the fabric is passed over a pin tenter frame 31 to a loop dryer 32 for removal of the water absorbed during scouring in tub 30. After drying, the fabric is wound on storage roll 33. Additional vacuum may be applied at 34, to remove residual non-adhering flock.

FIGURE 4 illustrates a fabric made according to this invention wherein the bonding stitch is in the form of a 8 combination chain and tricot stitch. FIGURE 4 illustrates both by side and bottom views the arrangement of the bonding stitches and the fiber or foam layer 43. Parallel rows of chains 44 pierce the layer 43 to form the complete chain stitch 40 and the rows are connected on the lower surface 45 of the fabric by continuous laid in, zigzag filling threads 41. The chain stitches 40 are applied under tension sufficient to cause the formation of ridges 42 in the polyurethane foam 43. A layer of fiber flock 46 is applied to the surface of ridges 42 by adhesive layer 47.

In FIGURE 5, an additional random exaggerated corduroy effect is provided by including random courses of laid in coarse warp yarn 50 between the lower surface of the foam or fiber layer 51 and the bonding stitches 52. The bonding stitches shown are of the half tricot type and comprise threads 57 and 58 which alternately pierce the layer 51 to form parallel chains of loops 56 on the upper surface of the layer 51. The threads 52 are applied under tension sufficient, in combination with the coarse yarn 50, to cause the formation of an exaggerated ridge 53 in the upper surface of the fabric. The ridges 53 are higher than the ridges 54 but are positioned in the same manner, i.e., between the parallel depressions 55 formed by the parallel chains of loops 56.

Corduroy fabric can be made according to this invention at a much higher production rate than a conventional corduroy fabric can be made. Furthermore, the process lends itself admirably to the preparation of one-way and two-way stretch corduroy fabrics which not only have desirable stretch characteristics but also incorporate the desirable thermal insulating properties obtained by the use of the elastomeric foam sheet.

I claim:

1. A method of preparing a corduroy fabric comprising the steps of (a) providing a stitch-bonded nonwoven base fabric, one surface of which has closely spaced parallel loop chains of stitching thread with ridges of fabric intermediate the chains, (b) applying an adhesive to the one surface of the base fabric, (c) applying fiber flock to the adhesive coating, (d) curing the adhesive and (e) removing excess unattached flock from the fabric.

2. The method of claim 1, wherein the base fabric is a stitch-bonded fiber batting.

3. The method of claim 1, wherein the base fabric comprises a flexible elastomeric foam sheet having an extension-limiting yarn system in the form of closely spaced rows of thread knitted into the sheet, the thread of each row piercing the sheet at intervals to form closely spaced parallel loop chains of stitching thread with intermediate fabric ridges on one surface thereof.

4. The method of claim 3, wherein the base fabric is a stitch-bonded nonwoven fabric having stretch and recovery characteristics in one direction.

5. The method of claim 3, wherein the base fabric is a stitch-bonded nonwoven fabric having stretch and recovery characteristics in two directions.

6. A method of preparing a corduroy fabric comprising the steps of (a) providing a durable foam fabric comprising a flexible elastomeric foam sheet and an extensionlimiting yarn system. in the form of a plurality of closely spaced rows of thread knitted into the sheet, the thread of each of the rows piercing the sheet on one surface of the sheet with ridges of the foam sheet intermediate the chains, (b) sizing the fabrics, (c) applying an adhesive to the one surface, ((1) applying fiber flock to the adhesive coating, (e) curing the adhesive and (f) removing excess unattached flock from the fabric.

7. A method of preparing a corduroy fabric comprising the steps of (a) providing a durable foam fabric cornprising a flexible elastomeric foam sheet and an extensionlimiting yarn system in the foam of a plurality of closely spaced rows of thread knitted into the sheet, the thread of each of the rows piercing the sheet on one surface of the sheet with ridges of the foam sheet intermediate the chains, (b) sizing the fabric with an aqueous solution of a water-soluble carboxylated acrylic polymer size, (c) drying the sized fabric, (d) applying a water base acrylic adhesive to the ridges of fabric on the one surface of the fabric, (e) applying fiber flock to the adhesive coated surface, (f) curing the adhesive, and (g) removing excess and unattached flock.

8. The method of claim 7, wherein the size is at least partially removed from the fabric by scouring on completion of the adhesive curing step.

9. A fabric comprising a stitch-bonded nonwoven fabric, the bonding stitches of which form closely spaced parallel depressions and fabric ridges intermediate the depressions on one surface thereof, and fiber flock secured to the parallel fabric ridges.

10. The fabric of claim 9, wherein the stitch-bonded nonwoven fabric is a stitch-bonded fiber batting.

11. The fabric of claim 9, wherein the stitch-bonded nonwoven fabric is one having stretch and recovery characteristics in one direction.

12. The fabric of claim 9, wherein the stitch-bonded nonwoven fabric is one having stretch and recovery characteristics in two directions.

13. A fabric comprising (a) a base fabric in the f rm' of a flexible elastomeric foam sheet having, as an extension-limiting yarn system, closely spaced rows of thread knitted into the sheet, the thread of each row piercing the sheet at intervals to form closely spaced parallel loop chains of stitching thread on one surface of the sheet and the thread being under sufficient tension to form parallel depressions under the loop chains and parallel ridges in the foam sheet intermediate the depressions on the one surface, (b) an adhesive film attached to and overlying the ridges, and (c) a layer of fiber flock secured by the adhesive film to the surface of the fabric.

14. The fabric of claim 13, wherein the base fabric is sized with a water-soluble size.

15. The fabric of claim 14, wherein the water-soluble size is a carboxylated acrylic polymer size and the adhesive is a cured water base acrylic adhesive.

15. The fabric of claim 13, wherein the fiber flock is precision cut tow.

17. The fabric of claim 13, wherein the extension-limiting yarn system is applied to the elastomeric foam sheet while the sheet is in a stretched condition.

18. The fabric of claim 13, wherein warp yarns are laid in on the surface of the fabric opposite the surface having the parallel ridges and are bound to the fabric surface by the extension-limiting yarn system to form corresponding exaggerated ridges on the one surface.

References Cited UNITED STATES PATENTS 2,964,421 12/1960 Rockoff 1l733 3,176,643 4/1965 Spencer 16l64 XR 3,215,584 11/1965 McConnell l6l64 3,274,806 9/1966 Duhl 66l92 FOREIGN PATENTS 225,737 12/1924 Great Britain.

ROBERT F. BURNETT, Primary Examiner.

JACOB H. STEINBERG, Examiner.

W. A. POWELL, Assistant Examiner.

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