US2922275A - Bucket process for novelty regenerated cellulose yarn - Google Patents

Description

J. P. HARTON Jan. 26, 1960 BUCKET PROCESS FOR NOVELTY REGENERATED CELLULOSE YARN Filed Oct. 28, 1954 INVENTOR ATTORNEY w T R A H E K O R B M E P H P E S o J IHIHHII Inn nited BUCKET PROCESS FOR NOVELTY REGENERATED CELLULDSE YARN 7 Joseph Pembroke Harton, Seaford, Del., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware Application October 28, 1954, Serial No. 465,314

1 Claim. (Cl. 57 -157) rates aten The importance of novelty continuous filament yarn for preparing textured or rough-surfaced fabrics is discussed in a copending application to Lohr and Lulay filed Oct. 28, 1954 as Serial No. 465,266 and now U.S.,

Patent No. 2,878,548. Briefly, the use of continuousfilament 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, slubyarns, knop yarns and boucls, tended to hang and catch in the fine apertures of the looms and sewing machines; Crinkled, nubby,continuous filament yarn provides wool-like flulfy, resilient nubs along the length ofyarn; but being a continuous filament, singlecomponent yarn, the nubs do not tend to hang or catch in apertures during fabric preparation. Furthermore, the variation in 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 efiect.

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 pulsate'd through spinneret orifices into an acidsulfate 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. It is this varying rate, alternating during each half thread revolution, that provides crinkling and changes the compact nubs into wool-like resilient, fluffy 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 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.

After a cake of predetermined size is formed within the bucket, it is dolfed (withdrawn from the bucket) and then washed, desulfured, bleached and dried. The dried cake is then unwound onto cones for shipment to fabric-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 prepared as indicated above, certain difficulties 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, continu- -ous 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 processthat does not resort to complicated gadgetry; i.e., without, destroying the basic simplicity of the process. Another object is to produce crinkled, nubby, continuous 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, througha 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 prevented.

Figure 1 is a view in perspective of one form of apparatus useful in the process of this invention.

In forming 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 passage 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 spinneret to interrupt the flow either periodically or in random fashion, or by introducing a pulsating flow of filament-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, a 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 cellu lose 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, between the feed-wheel and the. funnel guide, must bepreventedl This maybe accomplished by the deviceshown. in Figure 1.

In Figure 1,.the yarn 11 is shownas it leavesthe bath tank. It passes over the feedwheel 12. and snubber roller.13. After a second pass over feedv wheel 12 the yarn is ledover a guide 14 and then substantially vertically through a series of vertically arranged pins 15 on apin guide strip 16. It will be observed that successivepins on the strip contact alternatesides. of.the yarn and" thus prevent any balloon from forming. From'the lastpin, the yarn passes into thefunnelguide 171 The guide 17 is attached by a collar. and rod 18 to a traversingmechanism, not.shown. By traversingthe guide. up and downwithintherotating bucket.1 9, the yarnislaid down intheformof a. cake. 20; The guide. is. placed eccentric. to. the. axis. 21 of the rotatingbucket to lay down a cake.of crinkled nubby,continuous filamentregeneratedcellulose .yarn.

The cake is doffed and then. washed, desulfured, bleached and dried in the conventional manner. There are no tangles and snarls in the resulting cake to interfere with unwinding. The cones are then prepared by unwinding the cakes; the only precaution is to maintain lowtension 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 etfects 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-minimum 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 coagulating and regenerating bath, it is advisable to adhere to the restriction disclosed in copending application US. Serial No. 326,412 filed December 17, 1952 to A. Lulay and now Patent No. 2,729,539. That is, when spinning at speeds greater than 50. yards per minute, the filaments should be converged into a yarn within 12 inches from the spinneret. In this way, the nubs will be retained in the yarn fed to thebucket.

One of the important contributions of the present invention is the relatively simple solution for a rather knotty problem. By merely; preventing a balloon from forming between the feed wheel and the funnel guide,

an otherwise impractical operation becomes commercially feasible. The theory of this solution, which should not be considered limitative of th'isinvention, lies in making the yarnbehave'in the same wayfromatop tobottom of the traverse stroke and throughout-the spinning cycle. Thus, intermittent flashinginto a balloon withaccompanying 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 snarlsinthe'cake.

The crinkled, nubby,.continuousfilament, 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 someof the important end .uses.

' Having fully disclosed the. invention, I claim:

In the viscose process for producing cakes of crinkled, nubby, continuous filament, regenerated cellulose yarn, wherein freshly-formed nubby yarn is led over feed wheels and downwardly through a. traversing funnel guide into a rotating bucket, to form a cake of yarn therein, said funnel guide locatedeccentric to the axis of said rotating, bucket, the improvementwhich comprises passing the-yarn from the-feed wheel substantially vertically through a series of vertically arranged pins, such that successive pins contact alternate sides of the yarn to prevent ballooningv prior to passing the yarn into said funnel guide.

References Cited in the like of this patent UNITED STATES: PATENTS 1,489,199 Dreaper Apr. 1, 1924 1,663,856 Peterson Mar. 27, 1928 2,067,544 Radestock Jan. 12, 1937 2,47 3 ,520- Gwaltney- June 21,1949 2,556,290 Nelson June 12, 1951 FOREIGN PATENTS 78,180 Norway Feb. 26, 1951 164,050 Austria Sept. 26, 1949 524,430 Belgium Dec. 15, 1953 545;679 Germany. Mar. 4', 1932 804,336 France? Aug. 3, 1936

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