US2092800A - Manufacture of yarns or threads - Google Patents

Description

Sept. 14, 1937. w CK r AL 2,092,800

MANUFACTURE OF YARNS OR THREADS Filed April 18, 1934 GEORGE C TYCE WLLIAM A- DSCKKE 1N IENTOKS A'TTO fIVE r5 Patented- Sept 14, 1931 MANUFACTURE PATENT OFFICE 2.09am or m nus on 'rnncans William Alexander Dickie and George Crawford.

Tyce, Spondon, near Derby, England, alalgnon to .Celanese Corporation of America, a corporation of Delaware Q Application April .18, l9 4rserial No. 721,118

' Ill Great Britain April 25, 1933 3 Claims.

' This invention relates to the manufacture of spun yarns 02'' threads from artificial staple fibres.

Spun yarns may be produced either from natural staple fibre materials such as-wool or cot- 5 ton, or from continuous-filaments such as natural silk filaments or artificial filaments. In the latter case the continuous filaments may either be cut into staple lengths and then spun in the manner usual with natural staple fibres, or alternatively they may be broken into staple lengths by passing them between pairs of breaking rollers rotating at difierent speeds, so as to draw out the filaments beyond their breaking point. Methods of breaking continuous filaments in this manner for the production of spun yarns are described in U. S. application S. No. 696,375 filed 2nd November, 1933. The strength of spun yarns produced from continuous filaments in this manner -"-'depends upon the degree of twist which binds the fibres together, but in general is less than the strength of a continuous filament yarn of the same weight per unit length. It is one object. of the invention to obtain a spun yarn whose strength is comparable to or even exceeds the strength of '5 a yarn made from continuous filaments of like materials and of like weight per unit length.

According to the present invention continuous filaments which have been stretched beyond their elastic limit are converted into staple fibres, and

such staple fibres are spun into yarns. Stretched yarns which may most satisfactorily. be employed are those which have been stretched to a high degree, e. g. to 200, 300, or 500% or more of their former length. Such a high degree of stretching 88 may be efiected by treating the yarns during stretching with an agent adapted to assist the operation by reducing the elastic limit of the' ""material, as is described in U. 5. Patent No. 1,709,470 and U. S. applications S. Nos. 378,684

60 filed 16th July, 1929, 573,424 filed 6th November, 1931 and 602,844 filed 2nd April, 1932. Suitable agents which may be employed with yarns of cellulose acetate or other organic derivative of cellulose are acetone, ethylene methylene ether, I dioxane and similar cyclic ethers, and other agents referred to in the above specifications. A particularly convenient way of stretching .the yarns is to stretch them while they are in the form of a warp, e. g. as described in U. S. applica- I0 tion S. No. 602,8 14.

Continuous filament yarns which have been stretchedbeyond their elastic limit possess improved properties, and in particular a. greatly increased strength. In addition to the increased l6 strength, resulting from the stretching operation to which the filaments have been submitted, the

filaments are reduced in denier. When, therefore, such filaments are converted into staple fibres and spun into a yarn, not only is the increased strength of the filaments transmitted to the spun yarn produced, butv also the greater fineness of the filaments in itself has an effect of increasing the strength of the spun yarn produced and of imparting generally improved properties bf evenness and fineness thereto.

Continuous artificial filament yarns employed for the purposes of the present invention may have been stretched beyond their elastic limit at any stage in their production, either during or after their formation by extrusion and hardening by coagulation or evaporation.

While the invention may be applied to continuous artificial filaments of any type. e. g. to artificial silk of reconstituted cellulose, it is especially advantageous in connection with continuous artificial filaments of cellulose acetate or other organic derivatives of cellulose. Examples of other organic derivatives of cellulose are other cellulose esters such as cellulose formate, propionate or butyrate and cellulose ethers such as ethyl and benzyl cellulose.

As mentioned above the continuous filaments may be converted into staple fibres by cutting bundles of continuous filaments in one or more steps into lengths equivalent to the length of staple fibre of wool or cotton, or into any other desired lengths. Alternatively the yarns may be broken into staple fibres by passing them through breaking rolls rotating at diflerent peripheral speeds, the mass of staple fibres so produced emerging from the last pair of breaking rolls either being treated as a roving for subsequent the stretching or continuous filaments beyond their elastic limit also tends to reduce the extensibility, it might appear that some disadvantages would accrue from the cumulative reduction obtained. This difiiculty may readily be overcome, however, by treating the yarns in such a manner as to restore the extensibility to an extent which will enable them to be worked satisfactorily in textile operations for which they are destined. Conditioning treatments with this object in view are described in U. 8. application S. No. 696,184 filed 1st November, 1933. While such a treatment to restore the extensibilitymay be applied to a stretched continuous filament yarn before it is broken into staple fibres, it is preferred that the treatment should be postponed until after the formation of the spun yarn, so that loss in extensibility resulting from the breaking operation may also be recovered. The treatment may however be applied both to the continuous filaments before breaking into staple fibres, and to spun yam after spinning.

By way of example one form of apparatus suitable for the production of staple fibre yarns according to the present invention will now be described in greater detail with reference to the accompanying drawing, which illustrates the apparatus in side elevation.

In the drawing, stretched continuous filaments I are drawn from a supply bobbin 2 and through a guide 3 by means of feed rollers 4 which forward the filaments l to the first of two pairs of breaking rollers, 5, 6, 'I, 8. The feed rollers 4 are rotated at a peripheral speed slightly higher than that of the first pair of rollers 5, 5 so as to feed the filaments l to the rollers 5, 5.

The second pair of rollers I, 8 are rotated with a higher peripheral speed than the first pair of rollers 5, 6 so as to draw out and break the continuous filaments between the pairs of rollers, converting them into a continuous staple fibre product.

In order that the filaments may be securely gripped by each pair of rollers 5, 5, I, 8 the arrangement described in U. S. application S. No. 714,552 filed March 8, 1934, corresponding to British application No. 9311/33 filed 28th March, 1933 is adopted, so that,- despite the increased strength of the filaments which encourages slipping of the filaments through the breaking rollers, slipping may be substantially prevented. For this purpose, the lower rollers 5 and I are covered with protuberances which localize the pressure applied between the rollers, while the upper rollers 6, 8 are covered with a jacket 9 of slightly yielding material into which the protuberances of the lower rollers 5, I sink.

Between the pairs of rollers 5, 6 and I, 8 the filaments are guided and confined by means oi a guide tube It which is traversed to and troirom end to end of the rollers l, 5, 6, I, 8 by means of a traverse bar I I on which the tube III is mounted. The upper rollers 5, 8 are pressed down on the lower rollers '5, I by means of a bridge II which is springor weight-loaded by,means of a rod l2. The continuous staple fibre product I3 emerged from the second pair 01' rollers I. 8 proceedsto the guide I of a ring spinning device l5 by means of which it is twisted into a yarn and wound.

What we claim and desire to secure by Letters Patent is: I

1. Process for-the production of staple fibre yarns from continuous filaments, said process comprising stretching continuous filaments beyond their elastic limit, subsequently subjecting such stretched continuous filaments to a breaking operation to form a continuous staple fibre product, spinning such staple fibre product into a yarn, and submitting the spun yarn so produced to a conditioning operation to restore at least in part the extensibility of the fibres thereof.

2. Process for the production of staple fibre yarns from continuous filaments containing an organic derivative of cellulose, said process comprising stretching such continuous filaments beyond their elastic limit, subsequently subjecting such stretched continuous filaments to a breaking operation to form a continuous staple fibre product, spinning such staple fibre product'into a yarn, and submitting the spun yarn so produced to a conditioning operation to restore at least in part the extensibility of the fibres thereof.

3. Process for the production of staple fibre yarns from continuous filaments containing cellulose acetate, said process comprising stretching such continuous filaments beyond their elastic limit, subsequently subjecting such stretched continuous filaments to a breaking operation to form a continuous staple fibre product, spinning such staple fibre product into a yarn, and submitting the spun yarn so produced to a conditioning operation to restore at least in part the extensibility of the fibres thereof.

. WILLIAM ALEXANDER DICKIE.

GEORGE CRAWFORD TYCE.

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