US1732832A - Method of treating cellulose and viscose products - Google Patents

Description

Patented Oct; 22, 1929 UNITED STATES PATENT OFFICE METHOD OF TREATING CELLULOSE AND VISCOSE PRODUCTS No Drawing.

This invention relates, primarily, to methods of treating cellulose and viscose products; it has particular reference to a method of producing rayon elements for textile purposes; and it involves subjecting rayon filaments to a spinning operation whereby certain desirable characteristics are introduced into the product without materially aifecting other desirable characteristics inherent there- ]W in.

The principal object of my inventive-comcept is to produce the unique product constituting the subject-matter of my companion application filed August 11, 1926, Serial No. 128,702.

As set forth in that case, rayon (so-called), artificial silk (as it is also designated), and similar cellulose and viscose filaments are now very generally used in the textile arts for making fabrics, etc. It is well known that, while these filaments simulate genuine silk, they nevertheless are characterized by certain defects and objections: For instance, their wet-strength is appreciably below that of the filaments when first produced and beforebeing saturated or substantially moistened, as for washing or other purposes. Moreover, their exterior finish is quite harsh to the touch. Furthermore, they are not readily workable in weaving and knitting machines and, in consequence, have to be subjected to a sort of preliminary treatment before being fed to the needles of these machines. V

T have discovered-and my inventive-concept is predicated on the discovery-that if these cellulose filaments of commerce are subjected to a certain treatment, the undesirable characteristics mentioned are eliminated while the inherent desirable characteristics are retained and left unaffected.

Primarily, my concept resides in reducing the cellulose filaments to relatively short lengths-efl'ected by cutting them into predetermined, uniform lengthsand then inning these short-length sections to ether into a single, elongatedelement of pre etermined length and diametral dimensions, for use (say) in knitting or weaving.

Tn producing rayon or artificial silk for Application filed August 11, 1926. Serial No. 128,703.

commercial use by knitters and weavers, the manufacturer spins or extrudes cellulose through small apertured dies to produce fine filaments which commercially run from one and one-half deniers to six or eight deniers. These filaments are too small to be individually used by the knitter or weaver, and it is therefore the practice of the artificial silk manufacturer to group a number of these filaments. The popular sized artifical silk filament used for making hosiery and underwear is 150 deniers, which means that a thread-yard of 150 deniers would be composed of twenty-five six-denier filaments. These filaments are not twisted or spun together in the technical sense, that is, as fibers are spun together in the manufacture of cot-- ton, say, nor even in the sense that they are thrown, spun or twisted together in the manufacture of real silk, schappe-silk, or

worsted yarns.

The reduction or cutting of the filaments may for my purpose be effected in any desirable way. This step involves cutting the individual rayon filaments of the smallest commercially obtainable denier (one to one and one-half deniers) into relatively short lengths. Relatively short lengths means, here, lengths from one and a quarter to two inches. Experiments indicate that any length less than one and a quarter inches would not permit a suflicient number of interlockings of the individual filaments to provide the re quired strength to the filament. A length of two inches is the greatest which can be practically used for my purpose.

The short-length sections thus produced are (under my procedure) then subjected to a spinning operation, which usually includes, broadly, the following steps, namely:

(1) Opening the bale of filaments (as furnished by the rayon manufacturer) then (2) forming the filaments thus loosened into a soft mass and into H what is known as a lap, by a machine known as a picker, and whereby the batch of loosened filaments comes out in the form of a relatively thick sheet; then (3) carding the mass, which then emerges in the form of a very thin transparent webbing which, passing through a guide- 15 rovings into a new former, takes the form of a large fiufi'y rope own as a sliver; then (4) drawing the sliver in the drawing frame whereby the sliver is reduced to a more compact rope with 5 a very slight twist in it; then (5) slubbing the sliver to produce a roving, each roving being composed of a number of slivers but containing much less of the filament mass per (1 running inch than each of the slivers, each roving eing given an additional slight twist suflicient to hold the filaments together in the form of the roving or rope; then (6) effecting an intermediate drawing which again doubles the mass by compounding a number of single roving having a further slight twist; then (7) subjecting this roving to the action of so-called speeders whereby it is still further drawn and gets its first twist of any real amount, although the twist here is still very slight, comparatively; and (8 and finally) subjecting the roving to a spinning operation, efiected on spinning frames of any desirable character. and whereby the mass of filaments is drawn 5 through rolls both to attenuate it and to twist it, the twist given being in accordance with the length of cut filaments and variable to acgord with the use to which the product is to e put.

1 am aware that it is 'not new to prepare artificial silk or rayon filaments in short lengths and spin these by the so-called worsted or schappe spinning processes. The yarn resulting from these practices, however, is quite different in structure from the product resulting from spinning together of filaments and thereby very materially twisting and interlocking them to provide a product of substantial strength.

I am also aware of the fact that it has heretofore been proposed to cut artificial filaments into spinnable lengths and then, following an intermediate operation, spin the same. But my inventive-concept is distinguishable therefrom in that, in that instance, cotton is mixed with the artificial filament and, then, this mass is subjected to the action of a lappermachine, after which the cotton is combed out. The combing operation, I have found in practice, is detrimental to satisfactory spinning; and, besides, the introductionof the cotton to and its removal from the mass of cut filaments involves an expensive and unnecessary operation. During the lapping procedure, certain of the operations usually performed therein-for spinning cotton, for instanceare omitted so that the surface of the filaments are left as unsmooth as possible. The resultant of my procedure is an uncombed spun rayon textile element, unaffected by having been associated with any other fiber during the o eration of makin it spinnable.

It has een demonstrateg that when rayon filaments have been cut into short lengths and 65 spun to produce a textile element, the resultgreater flexibility.

ant product when wet shows afar less loss of tensile strength than an ordinary rayon filament of an equivalent diameter. The compounding of the short-length rayon filaments into an elongated element or yarn by spinning does not, of course, lend any greater wetstrength to the individual filaments; but it oes make the element compounded of these individual filaments of greater strength. Likewise, when rayon filaments have been cut into short lengths and spun to produce a yarn or element, the resultant product is far softer than rayon of equivalent diameter. This is obviouslythe consequence of breaking the long filaments of ordinary rayon into short lengths, thus imparting to the unit element Wet strength, as herein used, refers to the strength of material when saturated or substantially moistened.

After the element shall have been spun, as hereinabove set forth, it may be, and usually is, desirable to subject it to certain finishing operations; such, for instance, as stretching it for the purpose of restoring (so far as possible) any luster that may have been removed from the product during the spinning operation. To that end, I may treat such product in accordance with the procedure defined in the companion application of \V. M. Sternberg, filed August 27, 1926, Serial No. 131,966.

Where I have herein employed the ex pressions rayon, artificial silk, and similar terms, it is to be understood that they and equivalent designations for the material employed in connection with my invention, shall comprehend and include any thread, threadformation, filament or fiber, in the nature of a more or less lustrous textile element converted from cellulose (whether it be obtained from wood, cotton, or any other vegetable material) by means of chemical and mechanical processes, and whether such basic mass be known as cellulose or viscose. l/Vhere, in the claims, I refer to a rayonelement, I mean to designate the commercial product of rayon manufacturers as used by the knitter or weaver, which element is regularly composed of a plurality of fine rayon filaments arranged in substantial parallelism to provide a thread or yarn-forming group.

Where I have herein used the terms spinning and spun, etc., as involving essential steps in my procedure, I wish it to be understood that those terms comprehend that type of textile yarn manufacturing process which embodies as its essence, the drawing and twisting o the original sliver of ma terial into the finished yarn or thread.

y present invention may and has been practiced with the omission of some of the drawing and spinning steps hereinbefore described. The number of drawings and doublings and the amount of twist are variable lid till

according to the type of yarn desired and the character of raw material employed.

What I claim is:

1. Steps in the method of treating rayon filaments, which consist in providing artificial silk filaments in relatively short sections of substantially equal length and unassociated with other material, and spinning these short-length sections together in uncombed condition to produce a thread element which is characterized by relatively increased wet-strength and softness.

2. The method of manufacturing a textile element, which consists in reducing relatively long, finely attenuated rayon filaments into relatively short sections of substantially equal lengths, forming these short lengths only without other material and without combing into a lap, forming the lap into a rove of only rayon filaments, and then drawing and spinning the rove into 'a twisted yarn composed solely oi uncombed rayon whereby to produce a textile element which is softer and of greater wet-strength than an element of equivalent diameter made from the relatively long original filaments.

3. The method of manufacturing a textile element, which consists in cutting filaments composed solely of rayon into relatively short sections of substantially equal lengths, subjecting these cut-to-length sections to a lapping operation to reduce the naturally smooth surfaces thereof, and then spinning these sections, uncombed, to efiect a combinative association thereof,

lln testimony whereof, I aflix my signature.

ROBERT G. CAMPBELL.