US3390034A - Method for attaching sliced aligned filaments to a backing - Google Patents

Description

June 25, 1968 D. R. HULL 3,390,034

METHOD FOR ATTACHING SLICED ALIGNED FILAMENTS TO A BACKING Filed April 30, 1965 /BACKING FABRIC vfiwmmvmflmmmmw iazmz ./-CARD CLOTHING. BACKING W www rw; 11'111'. mocwmmcygzm m 6; o

L Mi -M 1' v; comomnnuusnrs w conmusaswssnowm i} Q mmmnusssuw W A 1 S nmsmmr ASSEMBLY ,-cARo CLOTHING mas -conrom5o mums ADHESIVE LAYER aouoms A FIBER ENDS T0 mums \BAOKING FABRIC i I CONTQRTED FILE FILAHENTS 4 "'4'4'w4'42 -1Lza4w-ADHESIVE LAYER BACKING FABRIC INVENTOR DONALD R. HULL BY W g/4% ATTORNEY United States Patent 3 390,034 METHOD FOR A'ITACHING SLICED ALIGNED FILAMENTS T0 A BACKING Donald Robert Hull, Wilmington, DeL, assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware Continuation-iu-part of abandoned application Ser. No. 239,675, Nov. 23, 1962. This application Apr. 30, 1965, Ser. No. 453,564

5 Claims. (Cl. 156-72) This application is a continuation-in-part of copending application Ser. No. 239,675 filed Nov. 23, 1962 now abandoned.

This invention relates to an improved means for attaching the ends of filaments to a backing and, more particularly, to an improved process for holding a plurality of aligned filaments in fixed relationship while the ends of the filaments are attached to a backing.

Heretofore various techniques have been proposedfor holding aligned filaments in fixed relationship in order that they could be more readily transported and processed, e.g. attached to a backing. The majority of these techniques have involved complex systems using mechanical bridges, holding blades and the like to attach neighboring filaments together. Although often suitable for certain purposes, each of these methods has nevertheless been attended by certain economic or quality disadvantages as to make their use unsatisfactory, sometimes impractical, for commercial purposes.

It is an object of this invention to provide a novel technique for keeping aligned filaments in fixed relationship to permit adequate attachment of the filament ends to a backing. Another object is to provide an improved process for attaching aligned filaments to a backing. A further object is to provide a novel process for controlling the uniformity of distribution of filaments when the ends of these filaments are attached to a backing to provide backed textile articles. Other objects will appear from the remainder of the specification and claims.

The above objects are accomplished by a process for making textile articles wherein first there is provided a body having a plurality of filaments aligned in generally the same direction within the body and having at least one substantially planar surface defined by filament ends. Thereafter a supported medium, such as an assembly of parallel wires embedded in a backing, is positioned within the body adjacent the planar surface so as to extend throughout a predetermined depth in perpendicular relationship to the planar surface. Since the medium, i.e. wires, extend in the same general direction as the filaments they thus serve to reinforce, support, and rigidify the filament alignment within the body of filaments. Subsequently the filamentary body is sliced transversely to the direction of the filaments in a plane parallel to the mentioned planar surface and just beyond the extremity of the medium, i.e. the ends of wires, to obtain an assembly of aligned short filaments embedded in the supported medium. Finally the free cut ends of the filaments are adhered to a backing and the supported medium is removed from the backed filaments.

The accompanying drawings schematically illustrate an embodiment of the process of the invention. FIGURE 1 is a representation of a side View of the supported reinforcing wires embedded in one end of the filamentary body and extending to a predetermined depth D. FIGURE 2 depicts a side view of the cut section of the filamentary assembly containing the embedded wires after the assembly in FIGURE 1 is sliced along the plane A-A'. Such slice is effected beyond the depth of penetration of the Wires and, in a preferred embodiment, is so directed as to provide a reinforced filamentary sheet having a 3,390,034 Patented June 25, 1968 thickness no greater than twice that of D. FIGURE 3 represents the side view of the cut section illustrated in FIGURE 2 after a backing has been attached to the free cut ends of the filaments. In addition to reinforcing the alignment of fibers during the slicing step, the supported wires also facilitate the application of pressure, with only minimum distortion of fiber alignment, necessary to adhere the structure to a backing. FIGURE 4 represents a side view of the textile article resulting from removal of the supported wires from the assembly shown in FIGURE 3.

A suitable method for practicing the present invention will now be described in greater detail. A tow consisting of a number of highly crimped continuous filaments is assembled in an open-ended mold such that the ends of each filament are aligned in the same direction toward the Open faces of the mold. The filamentary assembly is sliced with a knife in a plane parallel with one open face of the mold and transversely to the direction of the filaments protruding from one end of the mold to provide a smooth face of filament ends. Thereafter a sheet of card wire clothing attached to a flat backing is inserted into the cut face of filament ends so that the ends of the filaments are embedded inside the wire clothing to the depth of the backing holding the wires. The filamentary assembly is then pushed or extruded from the mold a short distance corresponding to approximately the desired pile height of the textile product. The filamentary assembly embedded in the wire clothing is then sliced with a knife transversely to the direction of the filaments at a distance just beyond the ends of the wires, leaving an assembly of cut aligned filaments held together by embedment in the wire clothing such that the most recently cut ends of the filaments protrude slightly beyond the ends of the embedding wires. The freshly cut face or planar surface consisting of filament ends is applied to a suitable backing containing a layer of an adhesive composition by pressing the assembly of filaments and wires firmly against the coated backing so as to embed the filament ends into the adhesive layer. After drying or curing of the adhesive to firmly attach the ends of the filaments to the backing material, the sheet of card wire clothing is removed, leaving a hacked article containing a number of filaments aligned in the same direction protruding as a pile layer from the backing to which they are firmly attached.

The invention is broadly applicable to filamentary materials in various 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, stutter box crimped tow, steam bulked tow, steam crimped continuous filament yarn, gear crimped continuous filament yarn, twist set-back twisted continuous filament yarn, knife edge crimped continuous filament yarn, two-component bulky continuous filament yarn, spun yarns, and many others. Similarly the invention is broadly applicable to filaments of widely varying composition, both synthetic and naturally occurring.

Typical of the fibers and filaments which may be employed are those made of polyamides, such as poly(hexamethylene adipamide), poly(meta-phenylene isophthalamide), poly(hexamethylene sebacamide), polycaproamide, copolyamides and irradiation grated polyamides, polyesters and copolyesters such as condensation products of ethylene glycol with terephthalic acid, ethylene glycol with a /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, co-polymers 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 US. Patent 2,837,501, vinyl and vinylidene poly mers and co-polymers, 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., polytetrafiuoroethylene, polytrifluorochloroethylenes) cellulose derivatives, such as cellulose acetate, cellulose triacetate, composite filaments such as, for example, a sheath of polyarnide around a core of polyester as described in US. 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 US. Patent 3,038,237, regenerated cellulose, cotton, wool, glass, metal, ceramic and the like. Blends of two or more synthetic or natural fibers may be used, as well as blends of synthetic and natural. Other fibers such as silk, animal fibers such as mohair, angora, vicuna are also suitable.

The initial body composed of a plurality of filaments aligned in generally the same direction 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 non-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 filaments is not critical and may vary from about 0.5 to about 50 denier or even higher.

In a preferred embodiment of the invention the filaments are contorted (e.g. crimped) as described in C. R. Koller US. Patent 3,085,922 such that the body employed is a porous material having a plurality of contorted filamentary structures which overlap, are aligned generally in the same direction, are interconnected throughout the three dimensions of the material and the material has a fiber density below 25 lbs./ft. Although a description of these materials including definitions of the terms used in connection therewith is fully set forth in the above Koller patent, the disclosure of which is specifically incorporated herein by reference, they will be briefly mentioned herein. By contorted it is meant that the profile (i.e. side elevation) of an individual filament is irregular (i.e. not straight) when the filament is viewed from at least one side. In addition to being contorted, it is necessary that such filamentary structures overlap adjacent structures throughout the three dimensions of the article. By the term overlap is meant that in at least one view, a filamentary structure crosses over, with or without touching or attachments, an adjacent filamentary structure. Furthermore it is critical to such structures that the contortion and overlapping of the filamentary structures do coact or are allowed to coact with one another. By coact" is meant that the contortion and relative placement of the filamentary structures are such that they assist one another in producing and maintaining the claimed structures both with respect to the general alignment of the filamentary structures and their spacing with respect to each other to achieve the desirable densities contemplated.

The adhesives which may be used when applying the backing are varied. By adhesive or glue is meant the material used to cause the filamentary structures and sheet materials to adhere to the backing or is meant the material used to constitute the backing Illustrative adhesives are: chloroprene rubber, elastomeric foams and sponges, butadiene-styrene rubber, polyvinyl chloride resin (e.g. those in combination with either a polymeric plasticizer or a monomeric plasticizer curable after application of the adhesive), polyurethane resins, polyamide copolymer of hexamethylene diamine and adipic and sebacic acids, casein resin, and epoxy resins such as the diepoxide of 2,2- bis(parahydroxyphenyl)propane. Illustrative backings are: woven fabrics such as burlap, canvas, and nylon scrim fabrics, knit fabrics such as nylon tricot, nonwoven fabrics such as polyethylene or polypropylene fiber webs, resin bonded polyethylene terephthalate fiber webs, papers of cellulosic and/or synthetic fibers, paper felts such as asphalt impregnated cellulose, elastomeric foams and sponges, plastic films such as from polyethylene terephthalate, polypropylene and polyvinyl chloride polymers, metal foils and rigid sheets such as fiber glass reinforced polyester resins, metals, ceramics and wood, elastic, stretchable or shrinkable fabrics and films, and the like.

For practicing this invention wire holding means may be employed which will provide a network of supported, elongated, spaced apart, wire-like protrusions aligned in the same genera-l direction such that the wire-like protrusions can be inserted between the ends of the filaments constituting one face of the aligned filamentary assembly. In the case where the filaments are contorted, as is preferred, the wires may simply be straight. With straight filaments (e.g., uncrimped) it is desirable to employ in connection there-with card clothing composed of bent wires. Whether they are bent or straight, all of the wires will normally be supported in a continuous backing which has suificient rigidity to be able to apply a pressure to the supported assembly of wires in order to attach the free ends of the filaments to a backing. The wires may be made of metal, synthetic plastic compositions, ceramic, or any other relatively rigid material.

If desired, a small amount of a binder composition may be employed in the practice of this invention in addition to the wire clothing in order to provide a greater degree of stifiness. The hinder or stifi'ening agent when employed can be applied to the assembly of aligned filaments in the mold prior to engagement of the wire clothing with the assembled filaments. In this instance, the material can be applied uniformly throughout the length of the assembly of filaments so as to provide a coating on the filaments to stiffen them and/ or to bond some of the adjacent filaments together at a number of crossing points of the filaments. Alternatively, the material can be applied to the free cut ends of the filaments opposite the engaged ends after the wire-engaged filamentary assembly is sliced off, in order to stiffen and/or bond together the filaments for a short distance along their lengths near the free-cut ends.

The binders which can optionally be used in accordance with the invention may be either soluble or insoluble, and may be either thermoplastic in nature or may be thermosetting which may then be reacted with a curing agent to form a cured polymer depending upon the use desired. If it is desired to remove the binder a soluble binder will be employed which may be either organic-soluble or watersoluble. Suitable organic-soluble binders include natural rubber or synthetic elastomers (e.g., chloroprene, butadienestyrene copolymers, butadiene-acrylonitrile copolymers), which may be used in the form of a latex dispersion or emulsion or in the form of a 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 polymer 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. Alcohol soluble polyamide resins are also suitable organic-soluble binders. Suitable water-soluble binders include materials such as polyvinyl alcohol, sodium alginate, acrylic acid polymers and copolymers such as polyacrylic acid, carboxymethyl cellulose, hydroxyethyl cellulose, dextrins, animal glue, soybean glue and sodium silicate. Suitable binders which are insoluble in organic solvents include polytetrafiuoroethylene 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 glycolmaleic anhydride-styrene; phenol-formaldehyde resins; resorcinol-formaldehyde resins; polyvinyl acetals, such as polyvinyl butyral and polyvinyl formal; polyvinyl others, such as polyvinyl isobutyl ether; starch, zein, casein, gelatine, methyl cellulose, ethyl cellulose, polyvinyl fluoride, natural gums, polyisobutylene, shellac, terpene resins and rosin soaps. Segmented polymers, such as spandex polymers, polyether amides, polyether urethanes (eg. those in US. 2,929,800) and polyester/urethanes are also suitable.

When inserting the wire clothing into one end of the filamentary assembly, the Wires should protrude a distance just short of the final pile thickness desired in the final textile article, so that only a very short length of each filament protrudes beyond the free ends of the wires at the time the transverse cut is made through the assembly of filaments. However, the amount of protrusion of the free ends of the filaments beyond the inserted wires may be varied somewhat depending upon whether or not a stiifening agent or binder is employed in addition to the wire clothing to provide added strength and adherence to permit both cutting of the transverse slice as well as attaching of the sliced assembly of filaments and wires to a backing.

The present invention provides a method for attaching an assembly of aligned filaments to a backing without the need for any stiffening agent or binder composition for holding the aligned filaments together during cutting and during attachment of the filaments to the backing. Another advantage of the present invention is that less pressure is required in attaching the wire-held filaments to a backing than that required in pressing an assembly of filaments held together with binder composition in the absence of any wire-holding means. The present invention is of particular advantage in the preparation of backed textile articles or pile fabrics having a medium to high fiber density in the pile layer; that is, such fabrics having a fiber density in the pile of at least one pound per cubic foot. Also, the invention is most useful when preparing pile fabrics having a pile thickness of at least inch.

The present invention invention may be used for preparing a wide variety of backed textile articles or pile fabrics such as floor coverings, carpets, tiles, upholstery fabrics, furs and fleeces, single and double faced blankets, suedes, and the like.

The following example illustrates a specific embodiment for practicing the present invention, but is not intended to be limiting in any respect.

Example The fiber used is a tow of 120 ends of continuous filament nylon yarns (102.0 denier, 68 filaments, /2 Z twist, trilobal cross section). This tow is bulked with steam under the conditions disclosed in Example 2 in Table III of Belgian Patent 573,230 and thereafter cut transversely to the yarns into 18" long sections. A number of these sections are assembled side-by-side in a metal mold 30" x 30" x 12" such that the yarns are all aligned in the same direction with their ends directed towards opposite open faces of the mold (30" x 30" faces). The yarns are compressed laterally to compact them to a density of 2.95 lbs./ cu. ft. Excess fiber protruding from the open top and bottom faces of the mold is trimmed off to provide a uniform surface of cut fiber ends. Onto the top surface of the cut fiber ends of this assembly of fibers is pressed 2. flexible sheet (29% x 29 /2") covered with card clothing such that the wires of the card clothing penetrate almost completely into the fiber assembly. This flexible card clothing sheet is made by abutting together strips of 1 /2 wide card clothing and cementing the backs of these strips to one face of a burlap fabric. The card clothing consisted of No. 26 HX wires projecting perpendicularly from a four-ply rubberized fabric with the wires projecting and spaced 4 rows, 3 twill, 8 noggs so as to give 128 points per square inch.

The fiber assembly is then pushed out of the top of the mold a distance of about /2" by applying a force on a plate against the bottom face of the fiber assembly. The fiber assembly is then sliced transversely to the fibers in a plane parallel with the card clothing sheet and -at a distance of about Ms beyond the ends of the card clothing wires. Thus, the flexible sheet of card clothing with a layer of approximately /2 long fibers intermingled with the card clothing wires is removed from the fiber assembly. The layer of fibers is aligned generally perpendicular to the backing of the card clothing and held in this position by the card clothing wires. This assembly is readily handled and moved without loss of fibers.

The sheet of card clothing with the cut layer of fibers is pressed onto a layer of rubber adhesive coated onto one side of burlap fabric so that the cut ends of the fibers protruding from the card clothing are embedded in the adhesive. The assembly is held together under light pressure until the adhesive layer sets by evaporation of the adhesive solvent. The ends of the fiber are well bonded to the burlap backing. The card clothing is removed from the pile fiber. There is obtained a soft pile fabric suitable for use as a carpet.

Although the invention has been described as particularly applicable to the lamination of porous filamentary bodies to a backing, it is to be understood that the utilization of card clothing in the manner described to enable uniform and effective slicing of the fibrous bodies is also a novel and highly useful feature of the invention. Thus this technique for slicing the fibrous body may be practiced as an intermediate processing step for obtaining the pile layer per se, e.g. without immediately laminating such to a backing. If desired, an adhesive composition may be applied to a face of the sliced, fibrous body portion prior to removal of the card wire clothing therefrom.

What is claimed is:

1. Method for slicing a filamentary body comprising the steps of:

(a) providing a filamentary body in the form of a porous material having a plurality of contorted synthetic organic polymeric filamentary structures, said structures overlapping and being aligned generally in the same direction, said filamentary structures being interconnected by a small amount of an organic binder composition at a plurality of contact points uniformly throughout the three dimensions of said material and said material having a fiber density up to about 2.95 lbs./ft. said body having at least one substantially planar surface defined by filament ends,

(b) placing card wire clothing in contact with said planar surface of said body and causing penetration of the card wires throughout a predetermined depth in said body in generally parallel relationship with said filaments to reinforce the alignment of said fi1aments,

(0) slicing said body in a plane substantially parallel to said planar surface and beyond said predetermined depth, and

(d) removing said card wire clothing therefrom.

2. Method of claim 1 wherein an adhesive composition is applied to the free cut ends of the severed reinforced portion of said body prior to removal of said card wire clothing therefrom.

7 8 3. Method for attaching aligned filaments to a backing (d) adhering the free cut ends of the severed, reincomprising the steps of: forced portion of said body to a backing and remov- (a) providing a filamentary body in the form of a ing said card wire clothing therefrom.

porous material having a plurality of contorted syn- 4. Method of claim 3 wherein the slicing of said body thetic organic polymeric filamentary structures, said 5 is effected to yield a severed, reinforced portion having structures overlapping and being aligned generally a thickness of one to two times said predetermined disin the same direction, said filamentary structures betance. ing interconnected by a small amount of an organic 5. Method of claim 3 wherein an adhesive composition binder composition at a plurality of contact points is applied to the free cut ends of the severed reinforced uniformly throughout the three dimensions of said 10 portion of said body prior to adhering said portion to a material and said material having a fiber density up backing. to about 2.95 lbs./ft. said body having at least one References Cited substantially planar surface defined by filament ends, (b) placing card wire clothing in contact with said UNITED STTES PATENTS planar surface of said body and causing penetration 15 $136,005 6/1964 Reltel'er 19-414 of the card wires throughout a predetermined depth 3,271,216 9/1966 Keller 156-454 X in said body in generally parallel relationship with 3,287,196 11/1956 Koller 156254 said filaments to reinforce the alignment of Said 3,290,729 12/1966 Maynard 19*114 fil t 3,334,006 8/1967 Koller 161-170 X (c) slicing said body in a plane substantially parallel 20 to said planar surface and beyond said predeter- EARL BERGERT P Examine"- mined depth, and HAROLD ANSHER, Assistant Examiner.

Claims (1)

1. 3. METHOD FOR ATTACHING ALIGNED FILAMENTS TO A BACKING COMPRISING THE STEPS OF: (A) PROVIDING A FILAMENTARY BODY IN THE FORM OF A POROUS MATERIAL HAVING A PLURALITY OF CONTORTED SYNTHETIC ORGANIC POLYMERIC FILAMENTARY STRUCTURES, SAID STRUCTURES OVERLAPPING AND BEING ALIGNED GENERALLY IN THE SAME DIRECTION, SAID FILAMENTARY STRUCTURE BEING INTERCONNECTED BY A SMALL AMOUNT OF AN ORGANIC BINDER COMPOSITION AT A PLURALITY OF CONTACT POINTS UNIFORMLY THROUGHOUT THE THREE DIMENSIONS OF SAID MATERIAL AND SAID MATERIAL HAVING A FIBER DENSITY UP TO ABOUT 2.95 LBS./FT3, SAID BODY HAVING AT LEAST ONE SUBSTANTIALLY PLANAR SURFACE DEFINED BY FILAMENT ENDS, (B) PLACING CARD WIRE CLOTHING IN CONTACT WITH SAID PLANAR SURFACE OF SAID BODY AND CAUSING PENETRATION OF THE CARD WIRES THROUGHOUT A PREDETERMINED DEPTH IN SAID BODY IN GENERALLY PARALLEL RELATIONSHIP WITH SAID FILAMENTS TO REINFORCE THE ALIGNMENT OF SAID FILAMENTS, (C) SLICING SAID BODY IN A PLANE SUBSTANTIALLY PARALLEL TO SAID PLANAR SURFACE AND BEYOND SAID PREDETERMINED DEPTH, AND (D) ADHERING THE FREE CUT ENDS OF THE SEVERED, REINFORCED PORTION OF SAID BODY TO A BACKING AND REMOVING SAID CARD WIRE CLOTHING THEREFROM.

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