US2513057A - Continuous aftertreatment of rayon - Google Patents

Description

June 1950 H. A. SCHRENK commuous AFTERTREATMENT 0F RAYON Filed Dec. 4. 1946 FROM 1 filaments are in thebaths.

Patente'cl June 27, 1950 UNITED; STATES PATENT OFFICE CONTI NUOUS AFTERTREATMENT OF RAYON Hans Alwin Schrenk, Arnhem, Netherlands, assignor to American Enka Corporation, Erika, N. 0., a corporation of Delaware Application December 4, 1946, Serial No. 713,905 In Germany July 14, 1941 Section 1, Public Law 690, August 8, 1946 Patent expires July 14, 1961 1 Claim.

This invention relates to the treatment of rayon and is more particularly concerned with a method and apparatus for the continuous wet treatment of a plurality of rayon yarns'moving between a point of extrusion and a point of col-- lection.

1 In the aftertreatment of rayon yarns, each composed of a multiplicity of filaments, it is known to pass the same in a continuous operation through a series of treating tanks wherein the yarns are guided beneath the surface of liquid in each tank and parallel to the surface thereof. Two types of guiding rollers are normally employed for this purpose, one type being located above the tanks for guiding-the yarns from one tank to the other, and the other type being wholly or partially immersed in the liquid of the tanks for guiding the yarns through the treating baths.

It has now been determined that it'is not necessary to drive all of the rollers, because if the rollers located above the tanks are driven, the rollers immersed in the baths can be freely rotatableas the yarns passing thereover will rotate the same. In order to maintain the yarns in parallel relationship during their passage through v the baths, it is preferable to provide the rollers above the baths with parallel grooves, whereas the rollers immersed in the baths can have a smooth surface.

In the foregoing process, it is necessary that;

the individual filaments should not be separated too much because then the filaments of the adjacent, moving yarns may become entangled.

The separation of the filaments is dependent upon the distance they travel through the bath, the speed at which they travel through the bath and the tension on the filaments which has been imposed in front of the first roller.

It is therefore an object of this invention to overcome the foregoing difficulties and to provide a method and apparatus for the aftertreatment of multi-filament rayon yarns wherein the yarns are subjected to adequate aftertreatment in passage through baths of relatively short physical length.

It is contemplated, according to this invention, to separate the component filaments of a yarn so as to cause the yarn to assume ribbon form during its passage through an aftertreatment bath, whereby the individual filaments may be On the other hand,

I travel through liquid I2.

2 better contacted with the aftertreating liquid.

It is a further object of this invention to provide apparatus for feeding yarn to, and withdrawing yarn from, baths of aftertreating. liquid in such manner that the threads will be properly spread into ribbon form in theirpassage through the aftertreating liquid in order to effect sufficient penetration of the treating liquid without entanglement.

Other objects and advantages of this invention will be apparent upon consideration of the following detailed description of a preferred embodiment thereof in conjunction with the annexed drawings wherein: I

Figure 1 is a diagrammatic view in vertical section of apparatus constructed in accordance with the present invention; and

Figure 2 is a fragmentary view in plan illustrating a typical driving connection for the apparatus shown in Figure 1.

Referring now in greater detail to Figure 1, the numerals II), II and I2 designate containers for the reception of aftertreating liquids I3, I4 and I5 which may be water, sodium sulphide and water respectively. The yarn issuing from a spinning position, not shown, is delivered to the container III by a driven roller I6. The yarn passes from driven roller I6 through aftertreating liquid l3. In container I0 there are located two freely rotatable guiding rollers I1 and I 8 around which the thread passes in its path of From the roller I8 the yarn is withdrawn from the container I tl by a driven roller I9 and roller I9, in addition to Withdrawing the yarn from the container I0, also feeds it into container I I. In passing through container II the yarn is guided by rollers 20 and 2| corresponding in structure and function to rollers I! and I8. The yarn is withdrawn from the container I I by a driven roller 22 corresponding in structure and function to the roller IS. The apparatus for guiding the yarn through the container I2 corresponds to that described in connection with container II and includes freely with bevel gears 30, 3| and 32 respectively to drive rollers I9, 22 and 25 respectively, all at the same speed. Shaft 26 also provided with .a bevel gear 33 whichzmeshes with a bevel gear 34 which drives one side of a change speed transmission 35 of any conventional design such as, for example, a P. I. V. transmission which is a, standard link belt variable speed drive mechanism. The letters P. I. V. stand for positive infinitely variable. The output side of the transmission 35 is "that are" possible within the scope of the invenconnected through a shaft 36 to the driven-roll- It has been discovered, as an important part, of this invention, that if the roller which feeds the yarn to the after-treating liquid is driven at a different speed from the rollers which withdraw the yarn from that liquid, it is possible to control the degree of separation of the component fila- .ments of the yarn in such a way as to best expose them for reaction with the after-treating liquid.

It is for this re son that the transmission 35 is provided, for by the-us'eof this transmission, it

is possible tO diiVe th roller lfi at a s'p'e'ed which I is different from the speeds of rollers 19, 22 and "'25; The range of variationbetween the speed of roller 16 and the speedof the other rollers can brewery small. It is found that upon increase in the speed of the roller 16 relative to the other rollers, filament separation is increased while a decrease in the speed of the roller 16' relative 'to the other rollers, results inadecrease in filamenu separation. "The phenomenon or filament separationo'f-thesort described is'not fully understood, but is believed to result from the elasticity of the wet threads.

Tests have shown that adequate'filament separation in all of the treating baths I3, 14 and 15 will be attained, for example, if each bath is 45 (if slifi'icient axial length SO 'that a plurality of yarns moving in parallel relationship may be accommodated thereby for simultaneous aftertreatment.

It can now be seen'that by practicing the method here disclosedandby using the apparatus here described, it is possible to adequately control filament separation in the passage of freshly spun yarns through aftertreatin'g baths with the re- 'tion.

-What is claimed is:

-A-;metho d -of=-aftertreating freshly spun substantially untwisted multi-filament rayon yarns which comprises feeding a plurality of such yarns "continuously in parallel relationship into a stationary, common bath at a, constant speed, passingkthe yarns from said bath and into, through and out of additional stationary and common I draws-1 from the' last baths while maintaining the yarns out of contact with each other and exposed on all sides to the bath liquid and in parallel relation to each other, withdrawing the yarns [from the last bath at a-cons'tant speed lower than the speed of I delivery thereof to the-first bath, and applyinga uniform propulsive foree to eaeh of the yarns between adjacent -baths under slippage permissive conditions, the propulsive force applied to the yarns between the respective baths being at substantially thesame speed a'sthe rate of yarn with- V th, whereby the yarns' are passed tm'o igh at i'least'some of the baths at a rate greater thantl'le rateof application df propulsive force thereto with resultant adjustment of the individual yarns due to inherent shrinkage and slip with respectt the propulsive force applied thereto and resultant passage of the yarns through the'baths in re1axed condition that Number Name Date 580,636 Burrows Apr. 13, 1897 1,971,627 Stuhlmann et a1. 'Aug.-28, 1934 2,066,168 Witte Dec. 29,1936 2,203,375 Weiss JuneA, 1940 2,239,636 Weiss -Apr.22; 1941 2,251,931 Gundelfinger 2 Aug. 12,1941 2,267,117 "Mann Dec. 23,1941 2,276,605

, Andrews"; -s Mar. 17,- 1942

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