US2869319A - Bucket process for novelty regenerated cellulose yarn - Google Patents

Description

Jan. 20, 1959 T. E. MITCHELL 9,

BUCKET PROCESS FOR NOVELTY REGENERATED CELLULOSE YARN Filed Oct. 28, 1954 I INVENTOR THOMAS EDGAR MITCHELL BY MW ATTORNEY United States v.

BUCKET PROCESS FOR NOVELTY REGEN- ERATED CELLULOSE YARN Thomas Edgar Mitchell, Chattanooga, Tenn, assignor to E. I. du Pont de Nernours and Company, Wilmington, Del., a corporation of Delaware Application October 28, 1954, Serial No. 465,313 3 Claims. (Cl. 57-157) This invention relates to the preparation of a novelty regenerated cellulose yarn particularly suited for the production of textured fabrics. More specifically, it relates to the production from viscose of crinkled, nubby, continuous filanient,'regenerated cellulose yarn by the bucket process.

The importance of a novelty continuous filament yarn for preparing textured or rough-surfaced fabrics is discussed in a copending application to Lohr and Lulay, filedOctober 24, 1954, as Serial No. 465,266. Briefly, the use of continuous-filament novelty yarns obviates the difficulties formerly faced by weavers and fabric-makers when they used novelty-twisted two and three component yarns. The wool-like, resilient, sharp nubs, characteristic of loop yarns, slub yarns, knop yarns and boucles, tended to hang and catch in the fine apertures of the looms and sewing machines. Crinkled, nubby, continuous filament yarn provides wool-like, fluffy, resilient nubs along the length of yarn; but being a continuous filament, single-component yarn, the nubs do not tend to hang or catch in apertures during fabric preparation. Furthermore, the variationin denier of the crinkled, nubby yarn is sinusoidal rather than sharp. This characteristic also tends to ease the weaving problem and, surprisingly, without sacrificing any of the novelty textured effect.

To prepare crinkled, continuous filament, regenerated cellulose yarn having wool-like resilient nubs along its length, viscose (an alkaline solution of cellulose xanthate) may be pulsated through spinneret orificesinto an acid-sulfate coagulating and regenerating bath. The nubby filaments obtained are then fed over feed wheels, Where regeneration into cellulose is substantially completed. From the feed wheels, the filament bundles, which make up the yarn, are led through a traversing funnel guide into a rotating bucket. The guide traverses up and down the depth of the bucket to throw the yarn by centrifugal force against the inner wall of the bucket and thus to form the cake. By placing the guide in a position eccentric to the axis of the rotating bucket, the yarn undergoes rapid fluctuations in the rate at which it is thrown against the inner wall of the bucket. this varying rate, alternating during each half thread revolution, that provides crinkl'mg and changes the compact nubs into Wool-like, resilient, flutfy nubs. Surprisingly, the crinkle effect tends to concentrate in the heavy denier portions (nubs) of the yarn. In general,.for optimum crinkling, the funnel guide should be placed about inch to /1 inch away from the central position over the bucket.

At this point, it is well to mention that between the point at which the yarn leaves the feed wheel and the point at which the yarn enters the funnel guide, a ballooning effect is observed. In reality, the ballooning is intermittent, varying with the rapid motion of the traverse. The pattern and frequency of ballooning also change as the cake builds up.

It is.

2,869,319 Patented Jan. 2o, 1959 After a cake of predetermined size is formed within the bucket, it is doffed (withdrawn from the bucket) and then Washed, desulfured, bleached and dried. The dried cake is then unwound onto cones for shipment to fabric-v makers. Coning involves withdrawing the yarn from the cake, usually upwardly, passing it through guides, over an emulsion roll and then to a reciprocating thread guide which leads the yarn onto a spool where the cone is formed, The tension between cake and cone is carefully regulated and kept very low to preserve the crinkle, in the yarn. The emulsion roll serves to apply a lubricating compound to the yarn.

If the crinkled, nubby, continuous filament yarn is pre-, pared as indicated above, certain ditficnlties of a practical nature are encountered. The most serious of these, from the standpoint of commercial operation is that the cake formed in the bucket tends to be characterized by tangles and snarls which make unwinding troublesome and, in some cases, the tangles and snarls are so bad that it is virtually impossible to. unwind the cake. Furthermore, even if the cake is untangled and then unwound, it is observed that the crinkle along the length of the yarn is not uniform which is a disadvantage.

The object of this invention is to provide an improved process for the production of crinkled, nubby, continuous filament, regenerated cellulose yarn. A further object. is to produce crinkled, nubby, continuous filament, regenerated cellulose yarn cakes 'that'can be unwound onto cones without trouble. A still further object is to provide a process of producing crinkled, nubby, con,- tinuous filament, regenerated cellulose yarn, wherein the crinkle is uniform throughout the length of the yarn. Other objects will appear hereinafter.

The objects of this invention are accomplished by a process wherein viscose is extruded through spinneret orifices into an acid-sulfate coagulating and regenerating bath to form filaments having nubs along their length; the resulting filaments passed over guide means such as feed wheels, through a traversing funnel guide into a rotating bucket, wherein a cake of yarn is formed, said funnel guide located eccentric to the axis of the bucket and wherein ballooning of the yarn between the feed wheel and the funnel is maintained in the same condition throughout the formation of the cake.

The figure is a view in perspective of one form of apparatus useful in the process of this invention.

informing regular continuous filament, regenerated cellulose yarn, a viscose filament-forming solution is led through the orifices of a spinneret into an acid-sulfate coagulating and regenerating bath. To form nubby or variable denier yarn a pulsating motion may be imparted to the viscose filament-forming solution prior to its p assage through the spinneret or the filaments after formation may be drawn at abruptly changing linear speeds It is preferred to impart a pulsating motion to the filament-forming solution prior to passage of the solution through the spinneret. This can be done by using a pulsating device between the metering pump and the spinneretto interrupt the flow either periodically or in randonrfashion, or by introducing a pulsating flow of filamer t-forming solution into a line leading from the pump to the spinneret. Some specific devices for producing this nubby yarn include a variable drive on a spinning pump, plunger pumps with plungers of unequal diameters, gear-type pumps with uneven teeth or with some teeth removed from the gears, 21 main pump with auxiliary pumps to supply extra spinning solution at intervals, and pumps which do not supply spinning solution but merely function to alter the pressure in the line leading from the spinning pump to the spinneret.

The nubby, continuous filament, regenerated cellulose 3 yarn is then led into a rotating bucket through a funnel guide, located eccentric to the axis of the bucket. However, for the improved process of this invention the ballooning, occurring betweenthe feed wheel and the funnel guide, must be controlled. This may be accomplished by the. device shown in the figure.

In the figure, the yarn 11 is shown as it leaves the bath tank. It passes over the feed wheel 12 and snubber roller 13. After a second pass over feed wheel 12 the yarn is led over a guide pin 14 which is mounted on strip 15. The strip is connected to the traversing mechanism, not shown, through the traversing rod 16. From guide pin 14 the yarn is led downwardly through the funnel guide 17 into the rotating bucket 18. The funnel guide 17 is also connected to the traversing rod 16. The guide 17 is placed eccentric to the axis 20 of the rotating bucket 18. When traversed up and down within the bucket, the guide serves to lay down the cake 22 of crinkled, nubby, continuous filament, regenerated cellulose. By having the guide pin 14 and the funnel guide 17, both connected to traverse rod 16, the distance between the guide pin 14 and mouth of the funnel guide 17 can be kept constant throughout the traverse stroke. This would maintain a constant ballooning condition throughout the spin cycle if not for the effect on ballooning of the build-up of the cake within the bucket. To compensate for the elfect of cake build-up, it is necessary to bring guide pin 14 slowly toward the funnel guide 17 during the spin cycle. This may be accomplished by telescoping the two sections of the traverse rod, 16a and 16b, so that section 16a, by means of a pawl arrangement, not shown, slips slowly down within section 16b.. Alternately, the strip 15 instead of being connected to traverse rod 16, can be connected directly to the traverse mechanism through a pawl arrangement. The funnel guide-17 would still be attached to the traverse rod 16. The pawl arrangement would serve to lower the guide during the spin cycle. In either case, the ballooning condition would be maintained constant throughout the spin cycle.

The resulting cake is then dotted, washed, desulfured, bleached and dried in the conventional manner. There are no tangles and snarls in the resulting cake to interfere with winding. The cones are then prepared by unwinding the cakes; the only precaution is to maintain a low tension to preserve as much of the crinkle in the yarn as possible. As cones, the yarn is shipped to fabricmakers.

This process is useful for preparing crinkled, nubby, continuous filament, regenerated cellulose yarn in deniers ranging from 200 denier to 4000 denier and higher. The nub spacing for optimum textured effects will vary with denier. .200 denier yarn should have a spacing of about 0.5 inch; 2000 denier yarn, a spacing of about 1.5 inches. Maximum-to-minirnum denier ratios will also vary with denier, in no case being less than 2:1. Contrast ratios as high as 8:1 is most desirable for 2000 denier yarn.

In extruding the filaments into the acid-sulfate coagu- One of the important contributions of the present invention is that it makes an otherwise impractical operation commercially feasible. By maintaining a constant balloon between the feed wheel and the funnel guide during the formation of the cake, an untangled cake is prepared. The theory of this solution, which should not be considered limitative of this invention, lies in making the yarn behave in the same way from top to bottom of the traverse stroke and throughout the spinning cycle. Thus, intermittent flashing into a balloon with accompanying pulling back of yarn already laid down in the bucket is prevented. Pulling back yarn and feeding excessive yarn alternately during the cycle probably contribute to the tangles and snarls in the cake.

The crinkled, nubby, continuous filament, regenerated cellulose yarn made by the process of this invention is useful for preparing textured fabrics of all varieties. Upholstery fabrics, drapery materials and dress goods are some of the important end uses.

Having fully disclosed the invention, Iclaim:

1. In the viscose process for producing a cake of crinkled, nubby, continuous filament, regenerated cellulose yarn, wherein a freshly-formed nubby yarn is led over guide means through a traversing funnel guide into a rotating bucket, to form a cake therein, said funnel guide being located eccentric to the axis of said rotating bucket, the improvement which comprises maintaining the ballooning condition between said guide means and said funnel guide constant throughout the formation of the cake. v

2. In the viscose process for producing a cake of crinkled, nubby, continuous filament, regenerated cellulose yarn, wherein a freshly-formed nubby yarn is led over feed wheels, past a guide pin and downwardly through a traversing funnel guide into a rotating bucket, to form a cake of yarn therein, said funnel guide located eccentric to the axis of said rotating bucket, the improvement which comprises traversing said guide pin and said funnel guide at the same rate and lowering saidguide pin toward said funnel guide to maintain the ballooning condition between said guide pin and said funnel guide constant throughout formation of the cake.

3. In the viscose process for producing a cake of crinkled, nubby, continuous filament, regenerated cellulose yarn, wherein freshly-formed nubby yarn is led over feed wheels, past a guide pin and downwardlyl through a traversing funnel guide into a rotating bucket, to form a cake of yarn therein, said funnel guide located eccentric to the axis of said, rotating bucket, the improvement which comprises traversing said guide pin and said funnel guide at the same rate and over the same distance and lowering said guide pin slowly toward said funnel guide to maintain the ballooning condition between said guide pin and said funnel guide constant throughout formation of the cake.

References Cited in the file of this patent UNITED STATES PATENTS 1,489,199 Dreaper Apr. 1, 1924 2,030,110 Keight Feb. 11, 1936 2,067,544 Radestock Jan. 12, 1937 FOREIGN PATENTS 545,679 Germany Mar. 4, 1932 644,806 Great Britain Oct. 18, 1950 804,336 France Aug. 3, 1936

Claims (1)

1. IN THE VISCOSE PROCESS FOR PRODUCING A CAKE OF CRINKLED, NUBBY, CONTINUOUS FILAMENT, REGENERATED CELLULOSE YARN, WHEREIN A FRESHLY-FORMED NUBBY YARN IS LED OVER GUIDE MEANS THROUGH A TRAVERSING FUNNEL GUIDE INTO A ROTATING BUCKET, TO FORM A CAKE THEREIN, SAID FUNNEL GUIDE BEING LOCATED ECCENTRIC TO THE AXIS OF SAID ROTATING

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