US2328074A - Manufacture of textile yarn - Google Patents

Description

Aug. 31, 1943. A. s. HUNTER MANUFACTURE OF TEXTILE Y ARN Filed July 16, 1940 Ricki bald 5. Hu

Patented Aug. 31, 1943 MANUFACTURE TEXTILE YARN Archibald Stuart Hunter, Kenmore, N. Y., as-

signor to E. L du Pont de Nemours a Company Wilmington, DeL, a corporationof Delaware Application July 16, 1940, Serial No. 345,778

2 Claims.

This invention relates to the manufacture of textile yarn. More specifically, itrelates to a process of producing novelty yarn composed of two or more strands of filaments, said strands having shrunk unequally during the production thereof to form a pebbly yarn structure.

Novelty yarns which are a composite of two or more single yarns of different lengths are known to the art. Such multiple yarns are produced by combining two or more single yarns having different shrinkage characteristics and thereafter subjecting the yarn to a shrinking treatment. In U. 8. Patent No. 1,976,201, a method is described for producing multiple yarn from cellulose acetate, wherein two yarns coming from a spinning machine are subjected to diiferent degrees of stretching',then are combined'into one strand and finally thrown on a' down-twister and collected on a bobbin. Thedegree of tension on one of the yarns is such that the yarn is stretched beyond its elastic limits. The composite yarn on the bobbin is subjected to thecustomary after-treatment procedure and then to, a. shrinking treatment. The filaments or the yarn which was subjected to the higher tension, will shrink to a greater degree and will, therefore, be

shorter than those of the yarn which was subjected to the lower tension.

Novelty or composite yarns made from cellu- Other objects of this invention will appear hereinafter.

The objects of this invention are accomplished, in general, by spinning several regenerated cellulose yams, or similar acid coagulated yarns, under diflerent tensions but without exceeding the elastic limit of the yam, .combining the yarns while still in the gel stateand twisting the sev- 'eral yarns, for example, into a bucket in accordance with the bucket spinning process.

' ner, the yarn is still in a strained condition, it

still retains the capacity to shrink. It possesses,

therefore, residual shrinkage which may be i measured or determined by subjecting the yarn to a boil-oi! procedure which comprises, for example, treatment of the yarn with a hot bath and permitting the same to dry without restraint.

For convenience, the present invention will be described with particular reference to the pro cellulose compositions such as ethyl cellulose.

yond the elastic limit thereof exhibits the higher degree of shrinkage and becomes the core, or the shorter member, of the composite yarn.

It'is an object of this'invention to provide a process for producing a rippled novelty yarn wherein the ripples are quite pronounced.

Another. object of this invention is to provide a process for the production of a rippled, or pebbly, novelty yarn during the conventional steps of spinning and purification, without the necessity of having additional shrinking and drying pro- It is a further object of this invention to provide a yarn which when woven into fabric will give depth to the fabric, thereby eliminating the uninteresting fiat appearance common to most fabrics.

The invention is also applicable to the productio of yarn by the cuprammonium process.

Referring to the accompanying drawing wherein Fig. 1 is a diagrammatic illustration of one arrangement for carrying out the tension spinning and doubling ste s of this invention, and

Fig. 2 is a diagrammatic illustration of--an arrangement for carrying out the tension-free dr ing step, this invention may, for example, be carried out as follows: Two yarns A and B freshly spun from spinneret I and 2 respectively, into a spinning or coagulating bath 3 are; while still and fed into bucket 6, preferably at equal rates of speed, during which procedure the two yarns are twisted together and collected as a cake 1. While the combined yarn is still in the gel state, it is wound on reel 8 from cake 1 to form skeins. The skeins are allowed to dry freely while under notension. The ripple develops as one component shrinks on drying more than the other. Any other suitable expedient for spinning one yarn at a. higher tension than the other may of course be employed.

Surprisingly, the yarn which was spun at the lower tension shrank to a considerably greater degree than the other yarn. This component was, therefore, shorter in the shrunken yarn and consequently constitutes the core, while the other yarn spun under the higher tension forms/ the ripples and gives the novelty efiect.

The following examples illustrate several detailed processes for carrying out the present invention.

Example I Viscose was spun through two identical spinnerets mounted side by side in a coagulating and regenerating bath to form yarns which were continuously removed, combined into one strand, and collected on a bobbin at a take-up speed of 2,000 inches per minute. The spinnerets contained 40 holes each. The diameter of the holes was 0.0035 inch. The yarn from one of the spinnerets, yarn A, was a 3'70-clenier, IO-filament yarn and was spun with a 6-inch bath travel. The

other yarn, yarn B, was a 3'70-denier, LO-filament yarn and was spun with a 90-inch bath travel.

' The combined yarn collected on the bobbin was washed acid-free on the bobbin and while still in the wet gel state, thrown on a downtwister which applied 3 turns per inch to the yarn. The

gel yarn was immediately reeled to skein and while in a completely relaxed state, was allowed to dry. During the drying, yarn component A which was spun under low tension decreased in length 9.8%, while yarn component B which was spun under a higher tension decreased in length 4%. The differential shrinkag obtained was therefore 5.8%. Because of the shrinkage difference, yarn component A became shorter than the other, said component becoming the base'yarn, while yarn component B was loosely twisted thereabout.

Example II washing, desulfuring and bleachin in that form. r

The two yarns were combined by twisting together on a downtwister while still in the wet gel state. The combined yarn was then reeled to skeins and dried in the relaxed state. Yarn A which was spun under low tension possessed a gel shrinkage on drying of 6.2%, while yarn B had a shrinkag of 2%, giving a differential shrinkage of 4.2%. A yarn effect similar to that of Example I was obtained.

Example III Yarn B of Example II while in the gel state was combined on a downtwister with yarn made as follows: A high salt index viscose, said index being 8, modified with 5% sodium sulfate was spun into a coagulating regenerating bath to give a yarn of 370-denier, -fi1ament, using a 6-inch 'bath travel and collected on a bobbin. The

combined yarns after purification were reeled to skeins and allowed to dry. Th gel shrinkage of the yarn spun from the high index viscose was 12.1%, while that of yarn B was 2%, giving a differential shrinkage of 10.1%. A yarn having a pronounced ripple eflect was obtained, the effect being produced by the long and short components thereof.

Example IV Two yarns having different filament sizes and spun under different tensions were produced as follows. Yarn A which was a 370-denier, 10-filament yarn was spun through a spinneret having 10 holes, each hole being 0.012 inch in diameter, using a 6-inch bath travel and collected on a bobbin. Yarn B which was a IO-denier, 40-filament yarn was spun through a spinneret having 40 holes, each hole being 0.0035 inch in diameter, using a SO-inchbath travel and collected on a bobbin. The two yarns were washed and purified on the bobbin and thrown on a downtwister which applied 3 turns per inch to the yarn. The

wet yarn was immediately reeled to skeins and or more times the spinning tension of the other component yarn or yarns. The high differential shrinkage of the component yarns is believed due to the fact that they are combined to form a composite yarn while still in the wet gel state. The yarn according to this invention is distinguished from that of the prior art in that the base yarn or the short yarn is the one which was spun under the lower tension. The present invention is further distinguished by the fact that the gel shrinkage between yarns spun under different tensions diifers to a greater degree than the residual shrinkage of the same yarn. By.,this fac,t,.it has been possible'to obtain novelty yarns having a more pronounced ripple effect than was produced by the prior art. For the production of a satisfactory novelty yarn in accordance with the present invention, it is essential that the shrinkage difference between the yarns must be in excess of 3%. For the best results, the shrinkage difierential between the two yarns should be from 5% to 10%, or even higher.

Th gel shrinkage of a yarn increases with an increase in filament denier, an increase in the total denier, and with a decrease of spinning tension. If two gel yarns are combined which have a wide difference in filament denier, a wide difference in total denier, and which were spun under widely different tensions, a high gel shrinkage differential will be obtained. Two yarns. which are identical with the exception that one has been spun under a much higher tension than the other, will give a satisiactory shrinkage differential though not as high as when all controlling factors have been utilized.

In the above examples, several ways or producing the novelty yarn of this invention have been described. The invention is not to be limited to these examples since it is possible to v y the conditions of spinning the yarn and still obtaimyarns having different gel shrinkage values. For example, a diiferent denier yarn may be obtained by maintaining all conditions the same, with the exception of the'pump delivery which may be increased for one of the yarns. The denier may be further increased by slowing down the take-up of the yarn. The denier difierential may be further effected by using spinnerets having large orifices.

In the examples, processes have been described in which the'yarns when reeled to skeins were acid-free and in some cases purified. It is to be understood that satisfactory results, and in some cases more satisfactory results may be obtained by a process in which acid gel yarns'are reeled to skeins and dried in the relaxed state.

' The spinning tension to which the yarn is sublected may be controlled by the length of bath travel. It may be further effected by the use of a series of rollers in the bath around which the yarn must travel. Additional tension may be applied by providing said rollers with vanes.

This invention has been described in terms of a yarn containing two components, but it' is obvious that three, or in some cases four or more components yarns may be twisted together to produce the composite yarn.

The present invention is described with particularreference to the production of regenerated cellulose from viscose solutions. The invention is, however, generally applicable to the production of yarn from any aqueous cellulosic solution which is coagulable' in an acid coagulating bath. Production of cellulosic yarns from aqueous solutions with the coagulation of the aqueous solutions in an acid or neutral bath will be referred to herein as a "wet spinning process.

In the process described in the examples, the

yarn was reeled to skeins and allowed to dry while relaxed. The process is not to be limited,

however,todryingtheyarninskeinformas satisfactoryresultswillbeobtainedbyanyprocessinwhichtheyarnisdriedwhilerelaxed,

The process of this invention makes it possible to produce a novelty rippled yarn during the standard steps of spinning and purification. It

is not necessary, therefore, to provide more than less slippery hand. The kinky, rippled yarn of this invention possesses the further advantage over the prior art yarns in that the 'ripples are permanent and will not be pulled out on stretch- Since it is obvious that many changes and modifications can be made in the detailed processes above described without departing from the nature and spirit of the invention, it is to be understood that the invention is not to be limited except as set forth in the appended claims.

I claim:

1. In the method of making a rippled composite yarn by wet spinning, at different spinning tensions, aplurality of yarns or different deniers composed of artificial cellulosic filaments, the improvements comprising applying to-the yarn of least denier a spinning tension at least two times the spinning tension of the yarn of largest denier, doubling said yarns, and drying the doubled yarns while they are still in the gel state bysupporting them in a loose condition free from tension.

2. In a method of making a rippled composite yarn by wet spinning, at difierent spinning tensions, a plurality of yarns of diil'erent filament deniers composed of artificial cellulosic filamerits, the improvements comprising applying to the yarn of'least filament denier, a spinning tension at least two times the spinning tension of the yarn of largest filament denier, doubling said yarns, and drying the doubled yarns while they ares'tillinthegelstatebysupportingthemina loose condition free from tension.

' ARCHIBALD STUART HUNTER.

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