US2903708A - Pile fabric - Google Patents

Description

P. M. COLE sept. 15, 1959 ILE FABRIC Filed May 2. 1955 i wwf/.

INVENTOR PAUL M COLE ATTORNEY 4 United vStates Patent O PILE FABRIC Paul M. Cole, Wilmington, Del., assigner to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware Application May 2, 1955, Serial No. 505,315

6 Claims. (Cl. 2"-278) This invention relates to non-woven material having upstanding pile or tufts, especially pile carpets of novel construction.

In recent years a productivity advantage of tufting machinery over looms has provided a growing market for pile fabrics, especially in the carpet field, as costs of the conventional woven wool product have soared. Despite the great suitability of nylon, for example, to such use because of high resistance to abrasion and to creasing or crushing, most of the tufting market has gone to the cheaper synthetic fibers, mainly because existing methods of manufacture require excessive amounts of the tufting material to provide a suitable product.

A primary object of the present invention is provision of a non-woven pile material in which substantially all the tufting yarn appears in the upstanding pile. Another object is construction of a highly resilient non-woven pile carpet. A particular object is production of an inexpensive non-woven material having nylon pile. Other objects of the present invention, together with means and methods for attaining the various objects, Will appear from the following description and the accompanying diagrams.

Figure l is a schematic representation of means for manufacturing a product according to the present invention. Figure 1A is an enlarged view of the indicated portion of Figure l. Figure 2 is a representation of the top surface and edge of a product of this invention at an intermediate sta-ge in its manufacture. Figure 3 is a similar representation of the material of Figure 2 at a later manufacturing stage. Figure 4 is a longitudinal sectional representation of a product of this invention, being the material of Figure 2 at a later manufacturing stage. Figure 5 is a partial sectional representation of a product variant of this invention obtainable from either the material of Figure 4 or directly from that of Figure 3.

In general, the objects of the present invention are accomplished by stretching a continuous elastomeric base material linearly, superimposing a yarn warp on the base with the component yarns oriented parallel to the direction of stretch, securing the warp to the stretched base by superimposing a plurality of rows of thread on the warp substantially perpendicular to the warp direction and forcing thread through the base to protrude thereunder at intervals along each row, and allowing the base to contract in recovery from the stretched condition, whereupon the Warp yarns form tufts between the sewed locations in adjacent rows; the portions of thread protruding through the base material, preferably in the form of dependent loops, are atlixed to the underside thereof, as by cementing, in the product. The invention comprehends, in addition to such a product having a looped pile sewed to the surface of an elastomeric base, a product similar except for having a cut pile in place of the looped pile; moreover, although the tops of the loops so formed may be cut or sheared in conventional manner, the cutting preferably is accomplished according to this invention before the base material has contracted more than just enough to raise the warp yarns somewhat from the base between the adjacent rows of sewing thread. Cementng of a backing of woven or non-woven fabric or of sheetat a peripheral speed greater than that of the first pair.l

The base then contacts the underside of yarn warp 4 between presser roll 5 and conveyor 10, which passes.

about drum 7 located a short distance beneath the presser roll and parallel drum 7 located some distance away at a speed identical with that of the presser roll.

As shown more clearly in Figure 1A, which is an enlarged view of region A of Figure l in which part of the warp and of the base has been omitted for clarity, the conveyor comprises belt 6 and, aflixed to its outer surface, a multitude of bars S extending parallel to one another crosswise of the warp; each bar carries for its entire length a row of pins 9 perpendicular to the surface of the belt, and these pins protrude into the underside of the elastomeric base.

Located above the conveyor and the base and superimposed warp are tracks Ill. and ll. also running in the transverse direction, i.e., parallel to the pin bars. Movl ably mounted on the tracks and supported over the warp is housing i2 supported on axles i3 and 13 visible at the sides. Protruding from under the front edge of the housing is a row of needles lll connected to conventional chenille type of sewing mechanism (not shown) inside the housing. Part of the top rear of the housing is cut away to reveal cutting mechanism 16, which comprises axle 17 (rotatable by means not shown) and a multitude of cutting discs 18 carried on the axle, which is adjustable vertically suiciently to move the discs into or out of Contact with the base sheet. Mounted above drum 7 at the exit end of the apparatus is release roll 21 against which the threaded material passes upon leaving the conveyor for windup upon a more distant roll (not shown). Located underneath the base material parallel to the conveyor drum but out of contact with the belt is cementing roll 22,v which has nap 23 on its surface. Adjacent hopper 24 supplies cementing composition 25 onto the roll nap, which contacts the under surface of the base. Roll 28 located underneath the base but apart from the cementing means is available to feed backing 29 onto the cemented underside of the base.

Operation of this apparatus is readily understood. With the lhousing for the sewing and cutting mechanism drawn to one side, the various rolls and drums are rotated to feed a length of the base material onto the rows of pins; the differential speeds of the holding and the extending rolls ensure that the base is stretched to at least several times its original length, and the pins hold it firmly at the extended length. Simultaneously with the feeding of the base, a yarn warp also is fed underneath the presser bar, and both base and superimposed warp proceed with the conveyor from the entrance toward the exit end. When a length of base and warp suicient to reach from one track to the other has been fed onto the apparatus (with the warp yarns held taut on the base between the presser bar and the release roll), the feeding is halted; then lthe sewing mechanism is activated and moved across the warp. The cutting mechanism is assumed inoperative for the time being. The needle action is synchronized with movement of the vhousing across the warp, with each needle running between a pair of adjacent pin bars. The sewing binds the warp yarns individually tothe base for their entire length between the tracks.

Patented Sept. 15, 1959 2,903,703 y A Y At this stage, the top surface of the treated material appears as in Figure 2, which shows only a small part of the entire surface, of course. Sewing threads 30 lie across warp yarns 34 and penetrate stretched base l at locations between adjacent yarns. threads protrude from the underside of the base supported on pins 9 extending upward from bars 8 aixed to belt 6.

Upon completion of this sequence of operations, with the housing containing the sewing and cutting mechanism off to one side, the rolls and drums are rotated again to bring a successive length of base and warp to be sewed as above. (When the cutting mechanism is inactive, alternate lengths of material may be sewed in opposite directions, that is, back and forth across the warp and base.) As the treated length of material leaves the conveyor belt about the release roll, the elastomeric base is permitted to relax to an approximation of its original unstretched length, preferably in a controlled gradual manner, as readily understood. Figure 3 shows the treated material after the occurrence of slight contraction; compressed by the diminution in length of the supporting base, each of the warp yarns arches upward between points of attachment by the sewing threads.

As shown in Figure 4, subsequent complete contraction of the base raises the warp yarns into a multitude of upstanding tufts or pile, and the accompanying slight increase in width and thickness of the base draws the sewing threads taut, holding the tufts securely to the base. The thread holds the base sheet under appreciable widthwise compression. The cementing roll attens the loops of sewing thread against the under surface of the base and cements them thereto, after which suitable backing material is applied to the cement-coated base, if desired, as the bottom-most element of the illustrated product.

Figure represents in similar view a product variant of this invention having a cut pile instead of looped pile. It is made as described above except for addition of the cutting step. The illustrated plethora of upstanding free ends replaces the surface consisting of upstanding loops, the original warp yarns having been rendered discontinuous by the cutting. This may be done by activating the cutting mechanism following the sewing mechanism across the warp. To eliminate any cutting of the base material, although slight impression of the cutting blades into the surface of the base is not harmful, the cutting step may be deferred until partial contraction of the oase has arched the warp yarns, as in Figure 3, when it may be accomplished by similar or other suitable cutting means located off the end of the conveyor. Alternatively, the looped pile of Figure 4 may be converted to a cut pile by shearing of the surface in conventional manner, although such a procedure is wasteful of the tufting yarn. The underlying base and the sewing threads are not visible through the pile, whether cut or uncut, the density of which is actually greater than can be shown conveniently in the diagrams.

The product of this invention has many advantages over existing types of non-woven pile fabric, as well as over woven fabrics having a pile surface. Substantially all the tufting yarn used according to this invention appears in the pile, being secured at the surface of the underlying base, whereas in conventional pile structures a goodly part of the tufting yarn does not go to make up the pile at all but instead is consumed in passing through and under some sort of backing material. The lessening in amount of tufting yarn required by this invention greatly reduces the fraction of the total cost attributable to the pile component; thus, nylon can compete favorably pricewise with rayon, for example, even ignoring the advantage of longer life inherent in the nylon product. Of course, other synthetic yarn compositions are suitable for the tufting component, including in addition to any of the various polyamide and copolyamide compositions conventionally Loops 32 of the sewing Y i known as nylon other compositions having wear characteristics requisite for the intended use. Because of their recognized resistance to soiling and yarn breakdown, continuous-filament yarns usually are preferable to staple here.

The product of this invention is more resilient than previous materials because force applied to the pile surface is transmitted substantially undiminished to the underlying elastomeric base, instead of being taken up to large extent by a relatively unyielding backing material. Thisv same feature of construction increases the wear life of the pile because it is not crushed against an unyielding backing but instead sinks under pressure into the resilient base. Similarly, less of a resilient base material is required according to this invention to provide carpeting with the same yield under foot as obtained in earlier construction.

An additional backing layer underneath the resilient base is often helpful in maintaining dimensional stability of the product of this invention where frequent or severe` handling is contemplated. Such a backing may be made of a wide variety of fibrous materials, including felt, burlap, and paper, for example; alternatively, it may be a sheet of plastic or rubber composition, which advantageously may be electrically conductive in known manner for the purpose of fostering dissipation of static charge that might be acquired by the pile.

The base material, which may also be electrically conductive, may be composed of any suitable natural or synthetic elastomeric material (or compatible mixtures thereof), including natural rubber, 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, polyureas, and polyurethanes. The base should be Capable of stretching to at least several times its original length and subsequently contracting to recover to less than twice its original length. Use o-f a backing underlying the base permits use of a somewhat thinner base, if desired; for example, if a stable backing is used (i.e., affixed appropriately to the underside of the base, at its recovered length), the thickness of a sponge rubber base may be as little as ls inch, whereas in the absence of a backing the thickness preferably would be increased by at least about 50%. Cellular (foam or sponge) construction of the base material provides a desirable combination of resilience and lightness of weight.

As used herein, cement and cementing or similar terms signify broadly materials and methods for accomplishing the indicated desired results. The coating applied may comprise any of a wide variety of adhesives, with aqueous or organic vehicle, or it may be a latex of natural or synthetic rubber or a solvent or near solvent for the base material or even for the backing, when one is used. Aflixing of the yarn underneath the base by whatever composition is used may be accomplished by application of it to a backing instead of or as well as to the base itself.

Of course, the distribution of the pile loops or ends on the surface of the product of this invention depends upon several variables, including frequency of sewing across the warp, spacing of the warp yarns, and relation between spacing of the pin bars and the extension and relaxation or recovery of the elastomeric base material. It has been found convenient when using a commercial mixed sponge rubber of from 1/8 to 1A: inch in thickness as the base to stretch the base to from 3 to 5 times its initial length and to sew with S-gauge cotton thread, at about 10 stitches to the inch, nylon (polyhexamethylene adipamide) multifilament having a total denier of about 3000, with 6 denier per filament, along rows spaced from about 1A, to :Vs inch apart. This base, after cementing of the loops with GR-S latex, recovers to about half again its original length,

which produces a pile about s inch high with approximately l0 to 12 tufts per inch in the original warp direction. The density in the transverse direction depends upon the number of warp yarns per stitch; although the drawings show only one yarn per stitch, which would provide a density of tufts per inch according to this example (corresponding to about 15,000 tufts per square foot) as many as several yarns may be secured advantageously by each stitch if desired, especially when a tufting yarn of low denier is employed.

In appearance, the product of the present invention upon bending around a corner, as on stairsteps, is not characterized by the pronounced separation of adjacent tufts notable in conventional pile products, retaining instead suicient density to obscure the base material substantially completely. The invention also permits production of pile patterns in color by using for the tufting yarn a warp printed in conventional manner. The equipment required is not out of the ordinary, and modification of existing equipment to perform this invention is quite simple; instead of the suggested chenille type of sewing mechanism, other conventional single-thread (chain stitch) or double-thread (lock stitch) machinery may be used, if not so conveniently. Many other advantages have been mentioned above, and still other inherent benets will become apparent to anyone undertaking to practice this invention.

The claimed invention:

1. A pile carpet comprising a continuous cellular elastomeric base and an upstanding continuous multilament yarn pile secured to the top surface of the base in closely spaced continuous parallel rows by rows of vertically tensioned thread extending at intervals through the base, said elastomeric base being under compressive stress in the direction of the thread rows.

2. The pile carpet of claim 1 in which the thread extending through the base is affixed to the underside thereof.

3. The pile carpet of claim l in which at least one pile yarn is secured to the base by the length `of thread between each adjacent pair of intervals at Which the thread extends through the base.

4. The pile carpet of claim l in which the thread securing the pile yarn t0 the base traverses the top` surface of the base in closely spaced continuous parallel rows with loops in each row extending at intervals through the base.

5. The pile carpet of claim 4 in which the frequency of the thread rows is on the order of l0 to the inch.

6. The pile carpet of claim 5 in which the number of intervals at which the thread in any row extends through the base is on the order of l0 to the inch and at least one pile yarn is secured by the thread between each adjacent pair of intervals, whereupon the pile density is at least about 15,000 ltufts per square foot.

References Cited in the le of this patent UNITED STATES PATENTS 1,606,899 Rockwood Nov. 16, 1926 1,859,922 Holland May 24, 1932 2,443,358 Michaelis June l5, 1948 2,636,460 Seiderman Apr. 28, 1953 2,642,571 Brown June 23, 1953 2,725,835 Mather Dec. 6, 1955

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