Pile article of backing, cushioning and pile yarn layers

March 23, 1965 j. _R heiks 3,174,451

PILE ARTICLE OF BACKING, CUSHIONING AND PILE YARN LAYERS -g—_{r w} - Filed March 26, 1963 _

<img file="US3174451A_D0001.tif" />

<img file="US3174451A_D0002.tif" />

mil····.......

<img file="US3174451A_D0003.tif" />

INVENTOR

JOHN ROBERT HEIKS

BY f*.

ATTORNEY

United States Patent Office

3,174,451

Patented Mar. 23, 1965

3,174,451

PILE ARTICLE OF BACKING, CUSHIONING AND PILE YARN LAYERS

John Robert Heiks, Wilmington, Del., assignor to E. I.

du Pont de Nemours and Company, Wilmington, Del., 5 a corporation of Delaware

Filed Mar. 26,1963, Ser. No. 268,860 1 Claim. (CI. 112—410)

This invention relates to novel layered structures, and more particularly to pile carpets having improved properties and methods of making same.

Carpets are generally constructed by attaching pile to a stiff backing fabric, usually latexed burlap. To provide softness and depth, a cushioning layer is usually positioned beneath the carpet during use. The stiffness of the backing fabric, however, prevents the cushioning layer from contributing fully to the compressional properties of the pile and neither the full value of the pile nor that of the cushioning layer is fully realized.

It is an object of the invention to provide a new cushioning material suitable for manufacturing carpets and similar articles. Another object is to provide an improved carpet having a novel structure and greater apparent depth and luxuriousness than conventional carpets while utilizing less pile material per unit area. Another object is to provide a process for producing the above-named articles. Other objects and means for attaining them will be apparent from the description of the invention given below.

According to the invention there is provided a layered article comprising a backing member, a fiber-on-end cushioning member consisting of short substantially parallelized fibers bonded together into an integral structure, the cushioning member being superimposed on and adjacent to said backing member with the fibers disposed at an angle to the plane of the surface of the backing member greater than about 10°, and pile yarn covering the surface of the cushioning member and connected to the backing member at regular intervals by means of segments of the pile yam passing through the cushioning member perpendicular to the surface of the backing member and in stitched engagement with the backing member.

The backing member of the articles of the invention may be any dimensionally stable sheet material including woven, knitted and non-woven fabrics of natural or synthetic fibers, such as burlap, cotton, sisal, wool, rayon, polyamides, polyesters, acrylonitrile polymers and copolymers, vinyl chloride polymers and copolymers, cellulose acetate, glass, metal, papers, and other stabilizing materials such as films, papers, felts, etc.

The cushioning member is in the form of a fiber-onend material consisting of short substantially parallelized fibers bonded together into an integral structure. A particularly advantageous combination of desirable functional properties, e.g. load support, superior aesthetics and favorable economies are realized when the fiber-on-end cushioning member is a porous, flexible, self-supporting sheet material as described in copending application of C. R. Koller Serial No. 787,662, filed January 19, 1959, now U. S. Patent 3,085,922. Additional features which characterize this preferred class of materials include the following: fibers therein are crimped and are composed of a synthetic organic polymer, the faces of the sheet materials are composed essentially of fiber ends, fibers are attached to one another at a plurality of contact points throughout the three dimensions of the sheet material, and the air within sheet constitutes at least about 50% of its volume. These sheet materials can be prepared such that the fibers are uniformly distributed throughout the sheet and at an angle to the plane of the face of the sheet greater than about 10°, such that fibers are attached to each other by at least about 0.50% binder based on the weight of the fibers and such that the fiber (density in the sheet is at least about 0.50 lbs./ft.³. Desirably these sheet materials have a substantially uniform distribution of fiber, binder and air throughout their volume.

By “substantially parallelized” as used herein, it is meant that though the fibers be crimped, bulked, or of some other irregular configuration, the mean axes of individual fibers are substantially parallelized. This orientation may be further illustrated by considering individual fibers to be surrounded by a circumscribing envelope or cylinder; the mean axes of these envelopes are substantially parallelized. The average angle formed by such axes with the plane of a face of the sheet should be at least 10° and, more commonly, essentially 90°.

The preferred cushioning members, as described in the aforementioned Koller application can be prepared by a method which comprises forming a plurality of bodies containing substantially parallelized fibers, either per se or in the form of other suitable filamentary structures, placing the bodies in a mold and forming a block while keeping the fibers substantially parallelized, impregnating the block with a binder composition, curing the binder, and cutting the resulting block at an angle of at least 10° to the plane of orientation of the fibers to obtain a porous, self-supporting sheet material.

An exemplary method for preparing suitable fiberon-end cushioning members will be described in greater detail with reference to the drawings.

FIGURE 1 is a loose batt or other body of substantially parallelized fibers, either continuous filaments or staple fibers.

FIGURE 2 shows the batt of FIGURE 1 after being separated into sections or strips 10 by cutting transversely to the aligned direction of the substantially parallelized fibers.

FIGURE 3 shows the sections 10 of FIGURE 2 rearranged so that the fibers in all sections are vertically oriented and are substantially parallelized with respect to each other.

FIGURE 4 illustrates a fiber-on-end block produced by bonding together the sections 10 of FIGURE 3 and also shows the manner of applying a backing member (11) to one of the larger surfaces or faces of the block. Normally the cushioning member employed will comprise a sheet or wafer which has been sliced from the bonded block by cutting the block at an angle traverse to the substantially parallelized fibers.

FIGURE 5 is a sectional side view of a two-layer article formed by bonding together the fiiber-on-end block (or a slice thereof) and backing member of FIGURE 4.

FIGURE 6 is a sectional side view of a three-layer article of the invention formed by tufting the two-layer article of FIGURE 5 with bulked pile yam 12 from the backing member side of the article.

The pile may be attached to the backing member in the same manner as in conventional carpets but, of course, the structure of the present invention is distinguished from conventional carpets in that the cushioning member is disposed between the backing member and the surface of the pile, thereby providing greater luxuriousness while affording economy due to the smaller amount of pile yarn required.

The initial fiber to be used in preparing the cushioning members may be in any of a variety of forms, for example, carded webs of substantially aligned staple fibers or bodies of substantially aligned filamentary structures prepared from a warp of sliver, top, roping, roving, tow, stuffier box crimped tow, steam bulked tow, steam crimped

3,174,451 continuous filament yarn, gear crimped continuous filament yarn, twist set-back twisted continuous filament yam, knife edge crimped continuous filament yarn, twocomponent bulky continuous filament yarn, spun yarns, and many others.

In preparing a cushioning member a wide variety of polymeric compositions may be employed. Typical of the fibers and filaments which may be employed are those made of polyamides, such as poly(hexamethylene adipamide), poly (metaphenylene isophthalamide), poly(hexamethylene sebacamide), polycaproamide, copolyamides and irradiation grafted polyamides, polyesters and copolyesters such as condensation products of ethylene glycol with terephthalic acid, ethylene glycol with a 90/10 mixture of terephthalic/isophthalic acids, ethylene glycol with a 98/2 mixture of terephthalic/5-(sodium sulfo)isophthalic acids, and trans-p-hexahydroxylylene glycol with terephthalic acid, self-elongating ethyleneterephthalate polymers, polyacrylonitrile, copolymers of acrylonitrile with other monomers such as vinyl acetate, vinyl chloride, methyl acrylate, vinyl pyridine, sodium styrene sulfonate, terpolymers of acrylonitrile/methylacrylate/ sodium styrene sulfonate made in accordance with U.S. Patent 2,837,501,. vinyl and vinylidene polymers and copolymers, polycarbonates, polyacetals, polyethers, polyurethanes such as segmented polymers described in U.S. Patents 2,957,852 and 2,929,804, polyesteramides, polysulfonamides, polyethylenes, polypropylenes, fluorinated and/or chlorinated ethylene polymers and copolymers (e.g., polytetrafluoroethylene, polytrifluorochloroethylenes), cellulose derivatives, such as cellulose acetate, cellulose triacetate, composite filaments such as, for example, a sheath of polyamide around a core of polyester as described in U.S, Patent 3,038,236 and self-crimped composite filaments, such as, two acrylonitrile polymers differing in ionizable group content cospun side by side as described in U.S. Patent 3,038,237 and the like. Blends of two or more synthetic organic fibers may be used, as well as blends of synthetic. fibers with natural fibers, e.g, silk, wool, mohair, angora and vicuna.

The cushoning members may be prepared from a wide variety of forms of fibers and filaments having any of the above-mentioned compositions,, such as,. for example, continuous monofilaments, continuous multifilaments, carded webs, warp, sliver, top, roping, roving, tow, bulked tow, bulked continuous .filament yarn, spun yarn, batts, felts, papers and other hon-woven webs, and the like. The fibers and filaments used as raw material may be either crimped or uncrimped, bulked or unbulked, drawn or undrawn or twisted or untwisted. The denier of the fibers and filaments is not critical and may vary from about 0.5 to about 50 denier or even higher.

For purposes of bonding the fibers together throughout the cushioning member the use of a binder is preferred over other techniques such as fusion and solvent coalescence. Normally the binders will be at least water-insoluble materials but, depending upon the use desired, may be either thermoplastic in nature or may be thermosetting for subsequent reaction with a curing agent to form a cured polymer. By “binder” is meant an additional material used to attach the fibers to each other. Normally these materials will be used in an amount of at least about 0.5% by weight based on the fibers. Suitable binders for this purpose include natural rubber or synthetic elastomers (e.g., chloroprene, butadiene-styrene copolymers, butadiene-acrylonitrile copolymers), which may be used in the form of latex dispersions or emulsions or in the form of solution, vinyl acetate polymers and copolymers, acrylic polymers and copolymers such as ethyl acrylate, methyl acrylate, butyl acrylate, methyl methacrylate, acrylic acid/acrylic and methacrylic ester copolymers, cellulose nitrate, cellulose acetate, cellulose triacetate, polyester resins such as ethylene terephthalate/ ethylene isophthalate copolymers, polyurethanes such as the polymers from piperazine and ethylene bis-chloroformate, polyamide polymers, and copolymers, methoxymethyl polyamides, vinyl chloride polymers and copolymers such as vinyl chloride/vinylidene chloride copolymer latices, polytetrafluoroethylene and ureaformaldehyde resin latices.

Additional suitable binder compositions include chlorosulfonated polyethylene; butyl rubbers, such as isobutylene/isoprene copolymers; polyhydrocarbons, such as polyethylene, polypropylene and the like and copolymers thereof; high molecular weight polyethylene glycols sold under the trade name of “Polyox”; epoxide resins, such as the diepoxide of bisphenols and glycols; polystyrene; alkyd resins, such as polyesters of glycerol with phthalic or maleic acid; polyester resins such as from propylene glycol-maleic anhydride-styrene; phenol-formaldehyde resins; resorcinol-formaldehyde resins; polyvinylacetals, such as polyvinyl butyral and polyvinyl formal; polyvinyl ethers, such as polyvinyl isobutyl ether; polyvinyl fluoride, natural gums, poly isobutylene, shellac, terpene resins and rosin soaps. Segmented polymers, such as spandex polymers, polyether amides, polyether urethanes (e.g. those in U.S. 2,929,800) and polyester-urethanes are also suitable.

The pile yarn used in the invention may be either spun yarn or continuous filament yarn as formed from any one of a number of well-known materials such as the polyamides (e.g., polyhexamethylene adipamide), copolyamides, polyesters (e.g., polyethylene terephthalate), acrylic polymers and copolymers (e.g., polyacrylonitrile), cellulose derivatives such as cellulose acetate and regenerated cellulose, and the like. Bulked pile yarns are preferred because better covering properties can be obtained with a given quantity of yarn. Particularly suitable bulked yarns are those made according to the methods described by A. L. Breen in U.S. Patent 2,783,609, and in Belgian Patent 573,230. Other suitable bulked yarns include those commercially available under the names of “Helanca,” “Banlbn,” “Fluflon,” “Saaba,” and the like. Sheath-core yarns can also be used for the pile.

In preparing the. novel articles of the invention, it is convenient as a first step to attach the cushioning member to the backing layer. This can be effected either with suitable well-known cements or by stitching, needle-punching, fusing, point bonding, solvent coalescing, stapling or any other suitable attaching means. Adhesives and cements that are well known for this purpose include latex cement, glues, paste, resin glues, and the like. In some cases it is desirable to unite the two layers simply by means of the pile yarn to be subsequently incorporated. With or without attachment of the two layers, pile yarn is repeatedly passed from the back of the fabric through both the backing layer and’ the cushioning member and thereafter back through both layers forming loops above the cushioning member.. Conventional tufting machinery can be utilized to provide loops of pile yarn at a selected distance beyond the cushioning layer. The exposed yam can be left in the loop form or, if desired, can be cut by known methods during tufting to form a cut pile structure.

In positioning the extended pile loops above the cushioning layer, it will be understood that to attain a given degree of covering power, the articles of the invention require far less thickness of pile yarn extending above the cushioning layer than the exposed pile thickness in conventional tufted carpets. One of the important features of the present structure is the superior resilience produced by the cushioning member which surrounds a substantial portion of the pile below its surface and thereby helps to support the pile yarn as well as add to the compressional properties.

It will be apparent that depending upon the ultimate use of the article, there can be attached to the exposed or underside of the backing layer one or more.

3,174,451 additional layers or coatings such as a coating of latex, layer of foam rubber or sponge rubber, anti-skid coatings or layers, anti-static layers, hair or jute batts, and the like. In some cases, it may be desirable to provide one or more of the additional layers for purposes of affording greater compressional properties or the like. The carpet structure may be finished by conventional methods, including scouring, dyeing, shearing, brushing, and the like.

An important feature of this invention is the provision of a carpet structure which employs less pile yarn and provides better compressional properties than carpet structures heretofore known. Hence, these structures can be produced at lower costs in comparison with conventional pile carpets for the reason that the requisite quantity of the more expensive pile component is minimized. Another advantage is a better definition of pile in that the pile yarn has less tendency -to mat. Still another advantage lies in the fact that the cushioning member increases the wear life of the pile surface.

The articles of the invention are useful in a variety of applications such as wall-to-wall carpeting, individual carpets and rugs, other floor cushioning articles, seat cushioning materials, apparel and industrial fabrics, automobile interior applications, and the like.

The following examples illustrate specific embodiments of the invention. All parts are by weight unless otherwise specified. The pile yarn illustrated in the examples is a bulky continuous filament yarn prepared by the process described in Belgian Patent 573,230. For this purpose three ends of 1,000 denier/68 filaments of polyhexamethylene adipamide semi-dull luster yarn were used, the filaments of which were drawn 4 times and had a Y cross section with a modification ratio of 2.2. The yarn was processed through a jet using steam as the turbulent fluid. The yarn, having a total twist of 0.5 Z, was fed to the bulking jet at a speed of 200 yards/ minute at a machine overfeed of 72%. The steam passing into the jet was superheated to 600° F. under a steam pressure of 85 p.s.i. The yarn fed to the jet was under minimum tension (i.e., “piddling” tension). The bulky nylon product after tensioning and relaxed boil-off was highly crimped and had a yarn denier of 6065.

EXAMPLE I

Three different pile carpets are tested for comparative carpet properties, using one sample prepared in accordance with this invention (sample 1) and two control samples. Sample 2 is a carpet prepared by known methods but using approximately the same weight of the same pile yarn as sample 1. Sample 2 is prepared by tufting the bulky 6065 denier nylon yarn directly through a woven burlap backing using a standard carpet tufting machine. The tufting is carried out to give a W pile height to the carpet, using %_c gauge (distance between rows of pile yam) and 4½ stitches per inch (distance between tufts in the backing). This produces a carpet of conventional structure having two layers; namely, a pile layer and a backing layer. This carpet is dyed red, following which a commercial latex is applied to the bottom of the backing and cured to a point of nontackiness. The pile yarn in this carpet weighs 18.7 oz. per square yard. Sample 3, a two-layer carpet made of 100% spun nylon pile yam tufted through a burlap backing, was a commercially purchased sample.

Sample 1 is a three-layer carpet of the invention with 100% bulky continuous filament nylon yarn in the pile, a cushioning member of 100% nylon staple in the form of fiber-on-end layer and a conventional woven burlap backing layer. The fiber-on-end cushioning member is prepared by first carding 15 denier, AVi staple nylon fibers and cutting the carded web to produce a piece 3 feet long and 18 inches wide. This web is placed on a flat surface and sprayed with liquid neoprene latex. A second carded web of the same size is placed flat on top of the first sprayed web and an additional coating of sprayed liquid neoprene latex applied. By repeating this operation a stack of 40 sprayed layers of carded web is assembled, having a height of 30 inches. After stand5 ing overnight at room temperature, the stack of webs is placed in an air oven at 250° F. until the latex is cured to the point of being non-tacky. The stack is then cut vertically (through all webs) into sections 2Ά x 21A x 18, and each section turned on its side on a flat surface 10 so that the parallelized fibers are standing perpendicular to the flat surface (i.e., all of the fibers are standing on end). Each of these cut sections is sprayed on its four vertical sides with neoprene latex and then the sprayed sections are pressed together and cured to give a fiber-on15 end batt measuring 18 wide and ZVi high. The cured fiber-on-end batt is then sliced horizontally to give a fiber-on-end cushioning member wherein the fiber height is 0.272. This fiber-on-end cushioning member is attached to a standard woven burlap backing by applying 20 “Hybond” neoprene latex cement to each layer and compressing the two sprayed surfaces together, curing the latex while holding the two layers under compression. The fiber-on-end portion weighs 6.05 oz. per square yard after curing (this weight is entirely fiber weight and does 25 not include the weight of the latex or the burlap backing) . Then bulky filament nylon pile yarn is tufted first through the backing and then through the fiber-on-end cushioning member to give a % pile height, using ^s4₀ gauge and 4.13 stitches per inch. The resulting three30 layer carpet is dyed red and latex applied to the bottom of the backing and cured thereon. The pile yarn in the carpet sample weighs 18.4 oz. per square yard.

The three carpet samples are tested for work of compression and bottoming effect and the results of these 35 tests are given in Table I. It is obvious that sample 1 of this invention has superior carpet properties to either of the control samples even though sample 3 contains a total of 35 oz. per square yard of pile yarn.

4θ Table I

Sample

Work of Compression (in. lbs./ sq. in.)

Bottoming Effect (inches) ⁴⁵ 1__________________________________________

2______________________________________

3__________________________________________

0.1450.100

0.0820.044

0.0980.068

EXAMPLE 2

This example demonstrates the superiority of a pile carpet prepared in accordance with the invention as compared to a control sample of conventional carpeting using a greater quantity of the same pile yarn. The control sample (sample 4) is prepared in exactly the same man⁵⁰ ner as sample 2 except it is tufted with 5½ stitches per inch instead of 4½ stitches per inch, and the total bulky nylon pile yarn weighs 23 oz. per square yard. The three-layer carpet of the invention used for comparison is the same as sample 1 above. Table II shows that ⁶⁰ sample 1 has superior carpet properties to sample 4 in spite of the fact that sample 1 contains 20% less pile yarn by weight than sample 4.

Table II

<td> 65 --------------------------------- Sample</td><td> Work of Compression (in. lbs./ sq. in.)</td><td> Bottoming Effect (inches)</td>

<td> 70 1_____________________________________</td><td> 0 145</td><td> n inn</td>

<td> 4______________________________________</td><td rowspan="2"> 0.100</td><td rowspan="2"> 052</td>

<td></td>

The carpet properties reported in the above examples were all determined by the same carpet compression test. 75 Samples of the carpets are preconditioned at 122° F. for

3,174,451 a minimum of two hours and then conditioned at 70 F. and 50% relative humidity for at least 16 hours prior to testing at atmospheric temperature and pressure. The tests are performed using the Instron tester, a constant rate strain tensile tester. A circular steel presser foot (four square inches) is attached to a cross head traveling at 0.2 inch per minute. The carpet sample (six inches square) is placed on a compression cell and the load applied to the carpet by the moving presser foot. Compression data are automatically recorded on a graph (i.e., load and distance) and with the utilization of an automatic integrater, the work of compression (area under loading curve) in inch pounds per square inch of carpet can be calculated using simple conversion factors. In carpet compression characterization, a carpet sample is compressed under a pressure limit of 20 p.s.i. for two successive cycles with a relaxation time of 120 seconds between cycles (time in which carpet is not under any compression). The first cycle is used to condition the sample and the actual characterization test parameters of work of compression and bottoming effect are taken from the second cycle. Using the second cycle the work of compression in inch pounds per square inch of carpet is calculated. Using the second cycle the actual compression of the carpet between 10 p.s.i. and 20 p.s.i. is calculated and reported in inches as the bottoming effect.

In addition to using conventional tufting methods for preparing the articles of the invention, one of two inverted tufting methods can, alternatively, be employed. In one of the latter methods the conventional tufting needle pushes a loop of pile yarn through the backing fabric. A special sewing needle and hook loops a sewing thread through the loop of pile yam and this sewing thread is pulled securely against the underside of the fabric when tension is applied by the tufting machine in forming a loop on the top side of the fabric. The sewing thread causes the pile yarn to be held in place with a minimum of yarn on the underside. Subsequently, cement can later be applied to further secure the pile yarn. In the second method of inverted tufting, a hollow needle would be substituted for the sewing needle and this needle would be equipped with a retractable wire. The sewing thread and hook would be eliminated. The hollow needle with the wire retracted would be passed through the loop of pile yarn in the same manner as the sewing needle above. The wire would then be extended as the needle is withdrawn from the pile loop. Tensioning of the pile yarn would then pull the wire tight against the underside of the fabric. Release of yarn tension and withdrawal of the wire would then leave a tiny loop of pile yarn projecting through to the underside. Subsequent cement application would secure the pile yarn in place.

This application is a continuation-in-part of copending application Serial No. 835,747 filed August 24, 1959, now abandoned.