US1597684A - Method of manufacture of artificial silk - Google Patents

Description

Aug. 3l 1926. 1,597,684

. c. c. JEssEN METHOD OF MANUFACTURE 0F ARTIFICIAL SILK I Filed Nov. 10, 1924 gnou/diez Patented Aug. 31, 1926.

UNITED STATES 1,597,684 PATENT OFFICE.

CIEIARLES C. J ESSEN, OF WILMINGTON, DELAWARE, ASSIGNOR TO ATLAS POWDER COM- PANY, OF WILMINGTON, DELAWARE, A CORPORATION 0F DELAWARE.

METHOD OF. MANUFACTURE OF ARTIFICIAL SILK.

Application led. November 10, 1924. Serial No. 749,094.

This invention relates to a method of manufacture of artificial silk and more particularly to a manner of handling the sampJ to prevent mechanical damage to the silk from handling in the several steps through which it passes.

In the manufacture of artificial silk cellulose is reduced to a syrup vlike consistency by various methods. Among these are the nitro-method, the viscose method, and the copper-ammonia method. In these several methods it becomes necessary to remove residual substances from the threads after the solution has been discharged from the spinnerets and brought to thread-like form by its passage through a suitable solidifying or precipitating bath. Y

For purposes of clearness I will describe the invention as applied to the copper-ammonia method of manufacturing artificial silk, though, as will be hereinafter set forth, the invention is of utility in connection with the other methods named.

i In the manufacture -of artificial silk by the copper ammonia process, cellulose is reduced to a syrup like solution by the action of copper sulphate and ammonia. This solution is forced through the fine holes of spinnerets directly into an alkaline precipitating bath which. instantly solidifies it to such an extent that it becomes a series of well defined threads of such strength as to permit of their being handled in the subsequent operations. It is very necessary however, to remove from the threads, substantially all traces of the chemicals used in bringing the cellulose into solution form. Some of the ammonia is removed in the alkaline precipitating bath and most of the remainder of the ammonia is removed by evaporation in the subsequent operations.

The removal of the copper is not eect ed as easily as the removal of the highly `volatile ammonia and, heretofore, the mechanical handling to which the silk was subjected in the removal of the copper has resulted in considerable damage to the same with consequent waste and loss.

In the manufacture of artificial silk, there are at present in 4general use, two methods of spinning. One is the so-called spool or bobbin spinning, and the other, pot spinning. In the first, or bobbin method, the individual and untwisted threads emerging from the precipitating bath are collected on rotating cylinders, spools or bobbins. The

-ess causes a waste of material and labor because if one filament breaks, it is `not picked up by the others, and causes tangling.

In the second, or pot method, the-threads in parallel are passed into a rapidly rotating centrifuge basket, or pot. A suitable guide vor traverse lays the thread against the wall of the pot, in the form of a cylindrical cake. The thread entering the pot is twisted by the rotation of the pot. When the desired quantity of thread has been collected, the pot is removed from the spinning machine, the thread reeled up in the form of a skein and given the necessary chemical and mechanical treatments to obtain the finished product. This method is superior to the rst method given above, but the thread is still liable to receive mechanical damage through handling the relatively weak thread in skein form during the intermediate treatments.

Broadly stated, my invention consists of plurality of spun threads, upon any suitable support, where it may be maintained under such slight tension, as will prevent it from tangling, and to subject the silk to all `subsequent operations, such as those necessary to remove the copper; washing and drying,

while it is still mounted upon said support. 'y

rectly from the pot of the centrifuge, and 100 winding it upon a cylinder, spool orA bobbin and subjecting it to a chemical treatment to decopp the same, i. e. to remove the residual copper, during such winding operation. This gives the strand a uniform 105 chemical treatment and eliminates many of the defects which are found in threads which do not receive a uniform chemical treatment.

The cylinders, spools, bobbins and the 11 e5 winding the twisted strand, composed of a the support. In other words, the silk is brought from the point of spinning to thel point of final drying on the same support (upon which it is initially wound,so that it bloes no?r have to be touched by human hands and is maintained in such form that it'can not become tangled, throughout its progress.

I do not limit myself as to the exact form of the spool or cylinder on which the thread is wound. The spool may be slightly tapered, i. e. of a conical shape and may or may not have flanges on one or both ends. Nor do I limit myself to the method of giving the thread the treatment or to the type of treatment. The cylinder may rotate about a horizontal axis, and may be partially submerged in the liquid -bath used for the treatment, or the liquid may be applied by spraying it on`the spool, or by flowing it on by a suitable device.

One form in which the decopping apparatus may be embodied is illustrated in the single figure of the accompanying drawing. This figure is a view partly in side elevation and partly in section of a simple form of apparatus for simultaneously windin the strand upon a cylinder and subjecting it to a bath for removing the copper, during such winding action. In the drawing, 5 designates the pot of a centrifuge in which a plurality of parallel threads have been twisted into strand formation as indicated at 6. rllhe strand 7 is led from the cake, deposited in the pot; through a support 8 and to and through a pig tail guide 9 carried by the lower end of a traverse arm 10. This traverse arm is Eivoted at 11 and is moved in one direction y a link 12 and a swinging arm 13 and in r the other direction by a spring 14. The

arm 13 is moved against the tension of the spring by the action of a pin 15 upon a rotative worm wheel 16. The worm Wheel 16 is mounted upon a drive shaft 17 and imparts motion to a worm 18 and shaft 19. J The shaft 19 carries a mandrel 20 upon which a cylinder 21 may be slipped, said cylinder being of such size as to frictionally engage the mandrel 2O and rotate therewith. The action of the traverse arm in conjunction With the rotation of the Inandrel and cylinder, causes theA strand to be deposited upon the cylinder in an open and porous mass. A bath of liquid indicated at 22 is so disposed with respect to the mandrel and c linder that the lower portion of the v,cylinder and the strands wound thereon rotate in the bath. Each successive layer of strands is directly exposed to the action of the liquid 22 and the strands.

are wound up in open and porous formation to permit the liquid to find ready passage 'to all parts of the mass throughout the winding of strands upon said cylinder;

It is to be understood that I do not claim as my invention the particular liquid employed for the removal of the copper. Dilute sulphuric acid is commonly employed for this purpose. It is common practice to remove the copper from the silk by the action of this chemical. The invention resides more particularly in the manner and time of applying the liquid to the artificial silk for the removal of residual chemicals left from the preparation of the solution from which the threads are formed. The chemical that' it is particularly desired toremove in the copper ammonia process is the residual copper, but it is manifest that the method is of utility in connection with either the viscose or the nitro processes. In the viscose process, it becomes necessary to remove residual sulphur compounds while in the nitro process it is necessary to dentrate the nitrocellulose filaments.

The cylinders 21 may be formed of any suitable material. I have found bakelite suitable for this purpose. After the strands are wound upon the cylinders, said cylinders constitute supports or carriers upon which the strands remain under light tension during the subsequent operations of washing and drying. These cylinders may be conducted to suitable washing apparatus Where they are sprayed with clear water and then be placed in drying ovens of conventional form and dried. After being dried the silk may be drawn directly from the cylinders to the swifts of a skeining machine.

From the foregoing description it will be seen that under this invention the strands are taken directly from the spinning machine and placed upon supports under light tension and are maintained in that con dition and upon said supports throughout the operations of decopping, washing, drying and skeining to brlng` them into their completed commercial form. The result of this is that it has been found in actual ractice that practically all of the flaws an imperfections heretofore met with in the production of artificial silk are eliminated and a high grade silk is had lat a minimum cost, because the usual waste and loss resulting from tangled skeins and the like, is avoided.

Having described my invention what I claim is:

1. The 'herein described method of manufacturing artificial silk which consists of winding the strands of spun and twisted threads, directly lfrom the centrifu e pot, after the latter has been removed om a spinning machine, upon a freely removable cylinder, while rotating the latter in the` presence of a bath. adapted to chemically treat' the strands, and thereafter Ec'arryin said cylinder bodily and with the stran s under light tension thereon, through washing and drying steps.

2. The herein described method of manufacturing artiicial silk which consists of Winding the strands of spun and twisted threads, directly from the centriu e pot, after the latter has been removed om a spinning machine, upon a freely removable,

Water and heat proof cylinder, while r0- tating the latter 1n the presence of a bath adapted to chemically treat the strands, and thereafter carrying said cylinder bodily and with the strands under light tension thereon, through washing and drying steps, the

latter steps being at elevated temperature.

In testimony whereof he aiixes his signa-` ture.

CHARLES o. JEssEN.

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