Tufted pile carpet and manufacture thereof

May 28, 1968

H. L. WILLARD ET AL

3,385,751

TUFTED PILE CARPET AND MANUFACTURE THEREOF

Filed Sept. 18, 1963

Sheets-Sheet 1

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INVENTORS

HOLLAND L. WILLARD TORN WILLY

ATTORNEYS

May 28, 1968

H. L. WILLARD ET AL

3,385,751

TUFTED PILE CARPET AND MANUFACTURE THEREOF

Filed Sept. 18, 1963

Sheets-Sheet 2

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FIG. 4

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JOHN WILLY

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ATTORNEYS

3,385,751

Patented May 28, 1968

United States Patent Office

3,385,751

TUFTED PILE CARPET AND MANUFACTURE THEREOF

Holland L. Willard, South Duxbury, and John Willy, Attleboro, Mass., assignors to Specialty Converters Inc., a corporation of Delaware

Filed Sept. 18,1963, Ser. No. 309,743

Claims. (CI. 161—66)

This invention relates to tufted pile carpeting and to the manufacture thereof. More particularly it relates to tufted pile carpet in which the base sheet is comprised of a thin sheet of foam plastic with a reinforcing fabric embedded in the thin foam sheet, and to the method of forming tufted pile carpeting on such a reinforced foam plastic sheet.

The material of the base sheet generally used in the carpet industry is a tightly woven jute fabric which has its warp and woof threads only slightly spaced apart. The woven jute fabric is passed through a tufting machine and looped pile elements of yarn are tufted through the woven fabric to form a pile of the desired height on the upper surface of the fabric with unsecured connecting lengths of the yarn of the pile elements on the lower surface of the fabric. Once the woven jute fabric has been tufted throughout, a latex binder is ordinarily coated on the exposed connecting lengths at the lower surface to secure them to the fabric and thereby provide an integral carpet construction in which the pile elements are securely held at the desired height above the woven fabric. Paper scrim is often adhered to the latex backing to add rigidity to the carpet. As will be seen jute is not an entirely satisfactory base sheet material and an improvement over this base sheet has long been sought for by the manufacturers of carpet. Heretofore most substitutes for jute have not been satisfactory either because they were much more expensive than the cheap jute material or they did not have the tensile or tear strength of jute.

There are several reason why woven jute base sheet has grown in disfavor in the carpet manufacture field. First, woven jute fabric is not readily available and in order to make certain that the carpet manufacturer can meet subsequent demands for an increase footage of carpet it is necessary that a rather large stock of woven jute fabric be maintained at all times. This is true because the woven jute fabric cannot be obtained from domestic manufacturers and the nature of the jute industry is such that yearly commitments must be made in advance thereby necessitating overbuying. Moreover, jute contains inherent impurities and natural oils which prevents any uniformity in the woven fabric used. As a result, it is almost impossible to tuft carpeting in advance and retain it in the warehouse for any length of time prior to dyeing. Invariably the impurities or oil work their way into the tufted pile and cause discoloration and chemical variations in tufted pile so that upon dyeing it is difficult to produce uniformity of color throughout the carpet. Furthermore, when some jute base sheets have been exposed to the elements it has been found that substantial measures must be taken to prevent fungus growth on the jute which is often susceptible to this kind of attack.

We have developed a much improved base sheet for pile carpet by using a thin sheet of foam plastic, such as urethane foam, in which a reinforcing member has been embedded. It is known that a discontinuous layer of reinforcing material can be embedded within a thin sheet of foam plastic in a continuous method to form a unitary structure which consists of a thin sheet of foam plastic with a reinforcing layer embedded substantially midway between the plastic sheet. By tufting yarns through a reinforced foam plastic sheet of this type, rows of pile elements extend out from one surface of the sheet and the foam is substantially compressed to a size essentially that of the thickness of the usual jute base sheet with the added advantage that the reinforced com5 pressed foam structure gives as good or better hand than the usual jute. With this construction the tufted pile is maintained within the reinforced foam sheet by the complex compressive and frictional forces set up within the compressed foam sheet. It has been found that unlike jq the pile elements which are relatively loosely formed on a jute fabric backing, the tufted pile loops formed on the reinforced foam plastic backing are retained rather firmly within its backing. Because of this the latex binder need not be applied immediately for there is little likeli15 hood that the pile elements will be pulled loose by ordinary handling. Moreover the reinforcing member provides the transverse and longitudinal resistance to stretching which is necessary in the handling of the carpet and which would not entirely be possible if foam plastic alone was 20 used, and, of course, holds the loops in place. Also, the nature of the foam plastic itself contributes greatly to the desirability of using it as a base sheet material. For example, there are no impurities or oil contained in urethane foam which would in any way affect the chemical 25 nature of the pile during storage, and owing to the chemical structure of the urethane foam substantially all fungus growth would be prevented from forming on the carpet. Finally, the reinforced foam is readily available and can in fact be continuously formed in a simple opera30 tion at the carpet plant itself.

Broadly stated, the pile carpet of the invention comprises a base sheet formed of a sheet of plastic foam with a reinforcing layer disposed within the sheet and substantially parallel to the broad upper and lower surfaces 35 thereof. Rows of pile elements extend through and out of the base sheet to form pile along the upper surface of the base sheet with the pile elements in one row being interconnected at the lower surface of the base sheet whereby the foam sheet is compressed against the reinforc40 ing layer and around a portion of the pile elements. It is also proposed to form a latex backing on the lower surface of the base sheet to hold the pile elements in the base, or to provide a backing sheet of foam which would serve both to secure the pile elements to the base and to 45 furnish a cushioning backing on the pile carpet.

One of the distinguishing characteristics in the carpet lies in the unique construction of the pile elements in the foam, and the resulting functional advantages it offers. To understand the distinctions between pile elements sup50 ported by the jute base sheet and that supported by the foam sheet, it is important to realize what occurs during the tufting operation. The jute base sheet is made of tightly woven threads which leave small irregularly spaced interstices. During the tufting through jute, the tufting needle 55 is often deflected such that the rows of carpet are not aligned and the individual pile elements are irregularly spaced from each other. Thus, the ordinary tufted carpet is characterized by pile elements which are held in the jute base sheet by friction interlock between the woven 60 elements of the jute.

In the carpet construction of the invention, by tufting through reinforced foam the pile elements formed have excellent support at their base and thereby are presented in a well-supported upright position. This type of construc65 tion has added advantages other than the structural strength which this type construction affords in that the presentation of the pile elements in such a supporting media and the nature of the foam material itself act in conjunction with each other to provide greater resilience to 70 compression to present a floor covering with greater cushioning effect underfoot than is provided with the same amount of pile tufted in a jute control.

3,385,751

Moreover, with the reinforced foam base sheet the reinforcing elements can be relatively widely spaced apart since the interstices between the reinforcing elements are filled with foam and there is little or no deflection of the needle during the tufting operation. Therefore, the tufts are well-defined and arranged in relatively straight rows, which rows and pile elements respectively are spaced from each other substantially uniform distances.

Another unique characteristic which deserve attention is also inherent in the use of foam as the base sheet. Foam can be cured by heat until it is non-tacky and self-supporting without fully curing the foam. We have discovered that when the pile elements are tufted through reinforced foam which is not yet fully cured, the foam continues to cure with time with the result that the foam becomes securely adhesively attached to the base of the pile elements so that the pile elements and the reinforced foam base sheet actually comprise an integrally constructed carpet.

The method of forming the pile carpet of the type described having a base which consists of a sheet of plastic foam with a reinforcing layer disposed within the sheet substantially parallel to the broad upper and lower surfaces thereof comprises the steps of tufting pile elements in rows through said base such that pile elements extend through and out of the base to form pile along the upper surface of the base with pile elements in one row being interconnected at the lower surface of the base, and compressing the foam sheet against the reinforcing layer and around a portion of the pile elements by the tufting. A backing is then applied to the lower surface to hold the pile elements in the base. This backing can be applied as a latex coating or an uncured foam backing could be applied to the lower surface to bond the foam backing to the lower surface and the foam backing would then be cured.

A preferred embodiment of the invention is described hereinbelow with reference to the drawings wherein:

FIG. 1 is an enlarged fragmentary perspective partly in section of pile carpet formed in the manner of the invention;

FIG. 2 is a section taken substantially along lines 2—2 of FIG. 1;

FIG. 3 is a side section partly broken away showing the tufting of the pile elements through the base;

FIG. 4 is an enlarged fragmentary perspective partly in section of another embodiment of the new pile carpet;

FIG. 5 is a schematic of apparatus for making the pile carpet of the invention; and

FIG. 6 is a section of the pile carpet formed to the method of FIG. 5.

Referring now to FIG. 1 the pile carpet 10 is shown. The pile carpet 10 consists essentially of a thin sheet 11 of plastic foam, preferably a polyurethane foam. Embedded midway between the upper broad surface 12 and the lower broad surface 13 is a discontinuous reinforcing layer 14 which in this embodiment is comprised of an open-mesh screen having transverse and longitudinally overlapping reinforcing strands 15 and 16. The reinforced foam sheet constitutes a base sheet 18 for the carpet, through which pile elements 19 are to be tufted such that a plurality of pile elements extend above the upper surface 12 in rows oriented transversely and longitudinally relative to the base sheet 18. In two examples, the material used for the pile elements was a nylon yarn and Acrilan respectively. (Acrilan is a trademark of The Chemstrand Corporation for a synthetic fiber made from acrylonitrile.)

As shown in FIG. 1, the pile elements 19 are in looped form and are formed from lengths of yarn extending in pairs through a single opening in the base sheet 18, and each pile element in a longitudinal row is interconnected with the next adjacent pile element by a connecting length 20 along the lower surface 13 of the base sheet 18. During the tufting of the yarn, the base sheet 18 is substantially compressed against the reinforcing strands 15 and 16 be4 tween its interstices and around the roots of the pile elements thereby reducing the thickness of the foam sheet to closely approximate that of ordinary jute base sheet and firmly holding the pile elements 19 in an extended position in relation to the base sheet 18 by a means of the complex compressive and frictional forces of the urethane foam in its compressed state.

In this embodiment the transverse and longitudinal orientation of the reinforcing strands of the reinforcing element 14 gives lateral stability to the base sheet 18 by precluding stretching of the base sheet 18 in a transverse or longitudinal direction as might occur by handling and inserting the base sheet through a machine.

As shown in FIG. 2 the reinforcing strands can be spaced apart such that rather large interstices are present therebetween. The foam in the sheet 11 fills the interstices so that during the tufting operation, depending upon the spacing of the reinforcing elements, one connecting length 20 of yarn is looped around a reinforcing strand so that a pile element extends between the interstices of the reinforcing elements. In an ordinary jute base sheet, there cannot be any large interstices; it is necessary for the jute to be tightly woven in order to provide a sufficiently tightly woven base sheet to hold the pile elements in the base sheet upon insertion therethrough. Accordingly, there is a substantial saving in the reinforcing strands needed in the base of the invention and this permits the use of polypropylene, nylon and other more expensive synthetic materials. Nylon has particularly been found to be desirable for it has better impact resistance and can move aside in the foam more readily so that it, rather than the tufting needle, will be deflected. It is also noteworthy that it has been found that cutting through the dense woven jute tends to reduce the tensile strength of the base sheet, whereas there is no cutting of the reinforcing strands in the reinforced foam base sheet of the invention and no corresponding loss in tensile strength.

In FIG. 3 a needle 21 with a length of yam 22 threaded therein is shown spaced above the base sheet 18 which is inverted so that its lower surface 13 faces uppermost as it is fed through the tufting machine. This needle is representative of one needle in a multi-needle tufting machine of the usual construction and is formed such that as the base sheet 18 is fed through the machine, the needle carries a single length of yam through the base sheet to form a loop which is caught by the loopers 23 of the machine and are held as the needle is retracted, thereby forming looped pile elements extending from the surface 12 of the sheet. As the base sheet is fed in step-wise fashion past the needles, the needle will insert the pile yam loops in rows extending transversely in relation to the base. Each needle in the machine also inserts longitudinal rows of the elements such that the portions of the pile element which lie along the lower surface 13 are interconnected with the adjacent pile elements in the same longitudinal row. As shown in FIG. 3 the base sheet 18 with the pile elements 19 formed therein can then be coated along its lower surface 13 with a latex coating 24 which serves to stiffen the resulting carpet and secure the connecting length 20 of yarn in the longitudinal row which is exposed at the lower surface of the base sheet. Often a paper scrim formed of relatively widely spaced warp and woof paper elements are applied to the back of the latex coating and preferably are coated with latex also.

Referring to FIG. 4 a base sheet 25 is shown which has a reinforcing layer 26 of randomly spaced reinforcing elements 27, which can be at least one randomly reinforced looped reinforcing strand, embedded midway between the broad faces of a foam sheet 28 and parallel thereto. Sealed to the broad faces of the foam sheet and defining the upper and lower surfaces 29 and 30 of the base sheet 26 are thin plastic sheets 31 and 32. It is to be noted that as shown the sheets 31 and 32 are separate thin plastic sheets, however when urethane foam is formed sometimes a layer of relatively dense foam forms a skin on

3.385.751 the broad surfaces of the foam sheet, and thin dense skin can have a similar useful effect as the thin plastic sheets. Pile elements 33 are tufted through the base sheet 25 in the same manner described in relation to FIG. 1, with the plastic sheets forming a protective surface at the roots of the pile element.

FIG. 5 shows schematically apparatus for performing the method of making the pile carpet of the invention. A mixing head 40 dispenses a foaming mixture 41 in its unreacted state in front of a pair of metering rolls 42. Also fed through the foaming mixture 41 and between the metering rolls is a discontinuous reinforcing layer 44 such as the open-mesh reinforcing element of FIG. 1. The metering rolls serve to force the foam mixture between the interstices of the reinforcing member and then the reinforcing member and the foaming mixture are conveyed between a continuous cover belt 45 and a carrier belt 46. As the reinforcing member and foaming mixture is fed therebetween the foam is expanded in situ in the interstices between the reinforcing elements and expands to form a sheet 47 having a uniform relatively coarse pore structure throughout its thickness and having a uniform relatively fine-pore structure at each broad face thereof, which constitutes the skin effect mentioned above. The fine-port structure forms a substantially smooth even skin surface at each broad face thereof. The uncured but fully expanded resulting foam sheet has the reinforcing element embedded midway between the broad faces of the sheet and parallel thereto. The sheet is then fed through a heating zone 48 which serves to cure the foam at least until it becomes non-tacky and self-supporting.

In this embodiment the reinforced foam sheet is then fed in a continuous operation from the heating zone 48 to a tufting machine 49 where pile elements 50 are tufted through the reinforced member in transverse and longitudinal rows in the manner described. After the tufting operation has been finished the carpet is passed to a second foam machine 51 and a mixing head 52 deposits a foam mixture on the lower surface of a pile carpet and then the pile carpet with the foaming mixture thereon is passed through metering rolls 53 and a thin foam sheet backing 54 is formed on the pile carpet around the interconnecting loops to hold the pile elements in their position and to provide a cushion backing as shown in FIG. 6. Of course, the lower surface can be coated with a latex coating as described in FIG. 3 and subsequently coated with a foam cushion backing as shown in FIG. 6, or can be coated with a latex backing alone or with a paper scrim.

It was particularly found that nylon and Acrilan pile tufted through reinforced foam sheets proved to be superior to carpets with the jute base sheet. Tufting and dyeing of the carpet with the reinforced foam base sheet proved to be generally easier and less problem prone than with jute base sheet. The latex backing and paper scrim applications were easily accomplished in the usual manner. Floor tests were conducted with a traffic in excess of 60,000 and the new carpet performed equal or superior to the carpet with the jute base sheets. Owing to the foam and the manner in which it supports the pile elements, residual compression ran from 10% to 25% better than the carpet with jute base sheets. Moreover, because the carpet had a synthetic structure throughout it was characterized by minimum moisture absorption in wet cleaning and spillage. Finally sound absorption is excellent with the new carpet, producing a better deadening effect in a room than does the carpet with the jute base sheet.