US3248274A - Weftless tape - Google Patents

Description

26, -l-` J. KARRASS WEFTLESS TAPE Filed March 30, 1960 is a tendency for the tape to slip in the metal seals.

United States Patent' O 3,248,274 WEFTLESS TAPE rlhornas I. Karass, St. Laurent, Quebec, Canada, assigner, by mesne assignments, to FMC Corporation, San `lose, Calif., a corporation of Delaware Filed Mar. 30, 1960, Ser. No. 18,525 2 Claims. (Cl. 161-60) This invention relates to weftless fabrics and in particular to a weftless tape formed of strands bonded together in parallel relation and adapted for heavy duty strapping. The present application is acontinuation-inpart of application Ser. No. 860,306, filed December 16, 1959, which in turn is a continuation-impart of application Ser. No. 432,499, filed May 26, 1954, Aand both applications now abandoned.

Recently attempts have beenmade to produce a tape formed of bonded parallel cords for use as a substitute for metal band strapping in the packaging industry. Such cord tapes have many advantages over metal strapping but to compete they must exhibit the following combination of properties: (a) sufcient flexibility so that they c-an be bent around a corner readily, (b) sufficient stiffness to enable them to be fed under a pallet or through a slot in an automatic packaging machine, (c) a unity of structure so that the individual cords do not separate in handling, packaging and shipment, (d) light weight and high strength, and (e) a sufficient roughnes or friction of surface to prevent slippage within a metal seal. This combination of properties has not heretofore been fully achieved.

Heretofore, to obtain the necessary high strength, use has been made of cords formed entirely of continuous filaments, bonded together with an adhesive. But because of the smooth surf-ace of the continuous filaments the adhesive does not bond the cords together sufficiently to prevent their separation and the suiface of the adhesive coated cords is so smooth that there In an attempt to overcome these faults the amount of the adhesive has been increased but this has resulted in higher costs, greater weight and a harsh stiffness and still the adhesion of the cords to each other was not materially improved.

In another approach to this problem, attempts have been made to produce such tapes by using parallel yarns formed of staple fiber such as cotton, staple rayon, etc. However, cotton yarns or spun rayon yarns are deficient in strength compared to continuous filament strands so that tapes made of staple have not been successful in replacing metal band strapping.

Therefore, it is a general object of the present invention to provide a tapeof strands having improved properties especially exhibiting high strength, low weight and substantially no tendency of the individual straifds to separate in use.

It is a further object of the invention to provide a tape of strands which can be made with a minimum amount of plastic binding composition and provide maxi- -mur strength approximately equal to the sum of the strengths of the individual fibers and which shows no tendency of the individual strands to separate in use.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

According to the present invention there is provided a cord tape formed of parallel strands bonded together by a film-forming plastic binder, at least every other strand comprising continuous filaments and some surface filaments that have portions that extend over and are bonded by the plastic to the surface of adjacent strands. The surface fibers which extend over and engage the ice'v adjacent strands may be discontinuous or severed fibers or they may be continuous but have loops or whorls that extend over and engage adjacent strands. Only a relatively short portion of the filament extends laterally to overlap and engage adjacent str-ands. The main portion of the filament extends along the bundle of the filaments and is securely anchored thereto.

Because some of the surface fibers on at least every other strand extend out and are bonded by the plastic to the surface of the adjacent strands, it may be said that the tape is fiber bonded because adjacent strands are anchored to each other through the overlying fibers as Well as by the plastic film. Moreover, the protruding overlying fibers reinforce the plastic film and decrease its tendency to crack between the strands.

Referring now to the drawing:

FIGURE l is a plan View of a segment of the tape;

FIGURE 2 is a fragmentary view on an enlarged scale with portions of the plastic broken away showing two adjacent strands of the tape;

FIGURE 3 is a View similar to FIGURE 2 but showing a modified form of strand; and

FIGURE 4 is aperspective View showing a tape embodying the invention and which comprises a plurality of strands.

The strands of this invention may be an untwisted strand or bundle of continuous filaments `or a strand or bundle of continuons filaments that has a low or a higher twist. The strand may also be two or more bundles or strands of filaments or yarns that have a low or higher twist and Which are cabled or plied together to form a cord.

For the continuous filaments used in the strands of the present tape there may be employed any continuous filament such as natural silk, artificial cellulosic filaments such as rayon, acetate and triaceta-te, also synthetic resin' filaments such as filaments made from nylon, polyesters, oletins, acrylic and modacrylic (a manufactured filament in which the filament-forming substance is any long chain synthetic polymer composed of less than but at least 35% by weight of acrylonitrile units), Vinyon, spandex (a manufactured filament in which the filamentlforming substance is any long chain synthetic polyamide having recurring amide groups as an integral part of the polymer chain), and continuous glass filaments. These generic terms are used as in the Federal Textile Fiber Products Identification Act of 8.

Strands comprising a major proportion of continuous filaments and a minor proportion of protruding filaments may be produced in a variety of Ways, by cutting or abrasion, Stretchbreaking or by loop formation, of which the following will be given by Way of example but not by way of limiting the invention.

The bundle of filaments during their manufacture may be passed over a rough or cutting surface and the filaments at the outer surface may be severed. Also, the bundle of filaments after their formation may be passed over an abrasive stone or cutting member while passing to a winding or twisting device.

There are available certain machines, such as the de Stains machine, in which a continuous strand formed entirely of continuous filaments is subjected to a predetermined stretch between spaced pairs of rollers so as to cause some but not all of the continuous filaments to break, the broken filaments protruding from the surface of the finished strand. By controlling the stretch, a yarn may be produced which will contain a major proportion of continuous filaments and a minor proportion of broken surface filaments.

A yarn composed entirely of aligned continuous filaments is passed in a highly relaxed, tensionless state and simultaneously subjected to a stream of air that causes some of the filaments to be blown out of the strand to form protruding loops or whorls in the finished yarn.

For the film-forming plastic binder there may be ernployed any plastic film-forming material such for example as viscose, water soluble and alkali-soluble cellulose ethers and organic-solvent soluble cellulose esters and ethers, also natural and synthetic gums and resins such for example as glue, gelatine, casein, and film-forming synthetic resins such as vinyl resins, nylon resins, polyester resins, vacrylic resins; also natural and synthetic rubber latices and solutions. The plastic should be nontacky, tough and iiexible when dry. The plastic may contain plasticizers, softeners, dyes and pigments selected with regard to the chemical nature of the plastic. I prefer to use polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral and acrylic resin solutions for the plastic.

In makin-g the tape, a plurality of strands or yarns having the laterally extending filament portions are drawn from a creel or other suitable supply and arranged inl juxtaposed side-by-side relationship. In this arrangement the strands are drawn through a bath containing a suitable fiexible film-forming plastic binder and while still held in the side-by-side compacted relationship are passed through squeeze rolls which squeeze out excess plastic and cause the outwardly extending cut or looped filaments to overlap and engage adjacent strands and become adhered thereto to thus serve to aid in binding the strands together. Not only do the overlapping filaments afford a stronger bond between the strands but they permit the use of a less total quantity of binder, which is an important factor from a commercial standpoint.

Since the yarn contains only a relatively small percentage of broken or looped filaments, the over-all strength of the complete tape is substantially the same as if the yarns contained all unbroken and aligned filaments.

A tape embodying the invention is shown in general in FIGURE 1 and comprises a plurality of strands most of which are continuous filaments. The strands are bonded together in side-by-side relationship by film-forming plastic material. Filaments adjacent the periphery of the strands have laterally extending portions which overlap and engage adjacent strands and these portions are embedded at least in part in the plastic. Only a small portion of the continuous filament makes up the laterally extending portion. By far the major part of the filament extends longitudinally of the strand or bundle substantially parallel to the other filaments and is securely anchored thereto.

FIGURE 2 illustrates diagrammatically and on a greatly enlarged scale, two adjacent strands of a tape made in accordance with the present invention. In this instance each strand is composed of two plies 11 and 12 almost entirely of continuous'and substantially aligned filaments 13 that are twisted together. Each strand contains, at least on the surface, a minor percentage of severed and protruding filaments designated at 14. The plastic coating is indicated at 15 and the thickness thereof is greatly exaggerated in the drawing for purposes of clarity and is also shown partly broken away so as to more clearly show the protruding fibers. It will be noted that the severed ends 14 extend from the parent strand sufficiently as to overlap the adjacent strand and that they are either entirely or partially embedded in the plastic coating,

this latter condition having been brought about by pass-A ing the tape through the aforementioned squeeze rolls as it left the binder path. The embedded portions of the fibers are shown in figures of the drawing in dotted lines. Thus it will be apparent that the protruding fibers 14 reinforce the plastic and impart added lateral strength to the tape while at the same time provide an improved anchorage for the plastic. The longitudinal strength of the tape is derived primarily from the continuous aligned filaments 13 and the bonding is due to the conjoint action of the plastic and the embedded protuuding fibers.

In the form of the invention illustrated in FIGURE 3 the strands 17 and 18 each comprise a bundle of substantially parallel continuous filaments. Filaments adjacent the periphery or the surface of the strands have intermediate portions in the form of loops or whorls 22 that extend laterally and overlap and engage the filaments of adjacent strands. The laterally extending portions as shown are at least in part embedded in the film-forming plastic 23. In this form of the invention, the overlapping looped portions reinforce the plastic and enhance the lateral strength of the tape While the aligned filaments give the desired high tensile strength to the tape FIGURE 4 shows a tape `of a form that may be generally used made up of five strands of continuous filaments but it is to be understood that normally the tape will comprise more than five strands. In this figure the protruding filaments are indicated at 29 and Iit will be seen that they are part of strands 27 and 2S but extend outwardly from those strands so as to overlap adjacent strands. As in those embodiments described above, the prot-raiding filaments 29 are embedded in the plastic 30 and serve to laterally reinforce the tape.

Thus it will be seen that the tape of the present invention is formed mostly of continuous filaments but has also a proportion of discontinuous or looped and misaligned filaments which overlap adjacent strands and aid in binding the strands together.

It will be seen that the present invention has provided a new and novel tape having the following combination of properties:

(a) Since the plastic layer is reinforced by the protruding fibers, the film-forming plastic layer can be made thinner thus providing a lighter, more flexible and less expensive product than is possible in the absence of the protruding fibers.

(b) Because the tape is formed of a major proportion of continuous filaments it is stronger than a tape formed entirely of spun yarns, such as cotton or rayon staple.

(c) Because of the protrudin-g fibers, the binding of the strands to each other is greater than is possible in the absence of such protruding fibers.

(d) The protnuding surface fiber-s impart a certain roughness to the surface of the finished tape thus increasing the frictional resistant between the tape and a metal surface when clamped in metal seals.

These novel properties fiow from the conjoint structure of the cords or strands in cooperation with the protruding fibers and the film-forming plastic binding material.

Having thus described the invention, what is claimed is:

1. A weftless tape comprising a plurality of parallel, substantially touching strands lying in a common plane, said strands each consisting of a substantially cylindrical bundle of filaments most of which are continuous and substantially aligned with one another but some of those lying on the surface of the bundle having outwardly extending portions which overlap adjacent strands, and an adhesive composition forming a film about said strands and holding the same together, the outwardly extending portions of the filaments being embedded in said film to thereby increase the lateral strength of the tape.

2. A weftless tape comprising a plurality of parallel, substantially touching strands lying in a common plane, said strands being bound together by a surrounding film of a plastic adhesive composition, each of said strands being composed primarily-0f a multiplicity of continuous filaments but containing a minor percentage of long, discontinuous filaments, at least some of said long, discontinuous filaments having the major portion thereof extending longitudinally of the strand and a minor portion extending laterally of the strand and overlapping an adjacent strand, and the laterally extending portions of the discontinuous filaments being embedded in said film of strength of the tape.

5 6 plastic adhesive composition to thereby increase the lateral 2,428,654 10/ 1947 Collins 156-180 2,680,272 6/1954 Radtke 154-46 2,869,967 1/1959 Breen 154-90 References Cited by the Examiner UNITED STATES PATENTS 5 FOREGN PATENTS 4/1905 Anet 156 441 226,268 12/1924 Great Britain.

9/1936 Alles 154 52 544,703 8/1957 Canada.

7/1937 Metcalf et aL 154 52 325,004 12/1959 Grat Britain.

gig? 115542138 10 EARL M. BERGERT, Prirrrary Examiner.

9/ 1942 Nutt et al. 154-90 CARL F. KRAFFT, Examiner.

Claims (1)

1. A WEFTLESS TAPE COMPRISING A PLURALITY OF PARALLEL, SUBSTANTIALLY TOUCHING STRANDS LYING IN A COMMON PLANE, SAID STRANDS EACH CONSISTING OF A SUBSTANTIALLY CYLINDRICAL BUNDLE OF FILAMENTS MOST OF WHICH ARE CONTINUOUS AND SUBSTANTIALLY ALIGNED WITH ONE ANOTHER BUT SOME OF THOSE LYING ON THE SURFACE OF THE BUNDLE HAVING OUTWARDLY EXTENDING PORTIONS WHICH OVERLAP ADJACENT STRANDS, AND AN ADHESIVE COMPOSITION FORMING A FILM ABOUT SAID STRANDS AND HOLDING THE SAME TOGETHER, THE OUTWARDLY EXTENDING PORTIONS OF THE FILAMENTS BEING EMBEDDED IN SAID FILM TO THEREBY INCREASE THE LATERAL STRENGTH OF THE TAPE.

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