US1770729A - Treatment of artificial silk - Google Patents

Description

Patented July 15, 1930 UNITED STATES PATENT OFFICE No Drawing. Application filed October 29, 1928, Serial No. 315,912, and in Germany March 12, 1927.

The object of the present invention is a method of production of a more flexible and less brittle artificial silk, especially prepared to protect the silk against damage in working. The process includes the following treatment. The artificial silk is spun and is then wound upon bobbins or the like or into centrifugals and, after being washed, but before further working, undergoes a treatment with oils, soap solution or similar suitable mate'- ria s.

It is well known that when the artificial silk'filaments are passed through a setting bath and thence directly to bobbins 0r centrifugal machines, these filaments are soft and somewhat gelatinous, and even the first chemical action is quite incomplete. It appears that the filament may (at this stage) consist of a casing of precipitated cellulose hydrate inclosing a core of unreacted viscose, and it is further well known that the filaments a very slight strength at this stage, they are not brittle and do not break from bending.

owever, after the reactions have been completed, the filaments are much harder and after drying (even incomplete drying) they are quite brittle. In the industry, it is not usual to refer to the product as threads until after the hardening is complete and the product dried. It is this brittleness which causes a great amount of breakage duringthe subsequent mechanical treatment.

Hereinafter, I use the term prior to any mechanical treatment to designate the stage of the raw filaments as they occur on the origilial bobbin or in the centrifugal to which the filaments dome, direct from the setting bath, and before drying of the said filaments. During the subsequent working of artificial silk, spun on bobbins or the like, there is often noticed the drawback that in mechanically 7 working the fine capillary threads, for instance in twisting and winding, they easily break, since they cannot stand the strains incident to drawing because of a certain brittle-. ness of the material. It is a well known fact that in the textile industry many methods and nconvenience.

apparatuses have been used to counteract this For instance, the so-called paraffining of the twisted yarns or threads has been proposed. Also other means have been employed as an attempt to make finished threads soft and flexible. All these well known methods, however, refer only to finished yarns or threads, as are alreadyprepared for use by weavers, knitters, etc. (fabricating operations).

the present invention aims at somethlng quite different. It will protect the artificial silk filaments spun onthe bobbins or the like, immediately after it has been spun and the chemicals sticking to it cleared oil", 1. e., before it undergoes further manipulations in the manufacturing of artificial silk yarn, as for instance twisting, winding, etc., (herein referred to as mechanical treatment) against possible damages occurring in the course of the aforesaid steps, as well as in the fabricatingoperations and further working. This is suitably done by treating the silk filaments, for example on said bobbins, with oil or an emulsion of oil or oil solution or soap solution and the like means for the purpose, such treatment being referred to generically as oiling the filaments. Thereby the artificial silk thread becomes soft and flexible, and capable of withstanding the possibilities of breaking and similar damage in the course of further treatment such as mechanical treatment and fabricatingoperations. Ithasbeendemonstrated by tests that artificial silk treated accordin to this invention, and similar artificial. sil that has not undergone this treatment, showed a considerable diflerence in the per centage of salable products. While the silk treated according to the stated invention shows practically no breaking of the capillary threads (filaments) there appears a considerable amount of such capillary breaks in the silk that had not undegone this treat- 95 ment. The finer the count of the various capillary threads, the more conspicuous is this difference, whereas with the heavier counts it is less noticeable. The working of this method in actual prac- 100 tice may for instance,

be carried out as follows :The artificial silk, spun on perforated bobbins or into centrifugals undergoes, immediately after the adhering chemicals have been washed oii', a treatment as described in the German patent application 13.115485 VII/8a., filed September 2, 1924, corresponding U. S. Patent application Serial No. 44,079 filed July 16, 1925, with the difference however, that instead of the washing liquid as therein stated, an oil or soap solution is used. As discharge any su'table textile oil can be used-the strength of the solution can be chosen according to the degree of suppleness (flexibility) wished for. Soap solutions or oil emulsions and similar suitable means can be used with equal success. Instead of the process mentioned in said earlier patent application, also other modes 0 applying the oily material may be used. The soap solutions and oil emulsions as referred to may be generically included in the expression aqueous vehicle carrying an oily material, all as a freely liquid mixture.

The lubricating (softening) liquid can also for instance be discharged by pressure through the layers of the threads from the inside to the outside of the perforated bobbins or the cakes while in the centrifugals. The bobbins with the washed and if required or the so treated cakes may also be immersed in the lubricating liquid or the lubricating liquid may e sprayed on them.

I claim In the treatment of artificial silk, the herein described step of oiling the same by the use of an aqueous vehicle carrying an oily material, all as a freely liquid mixture at a stage of the process not later than while the silk is still wound upon a bobbin or into a centrifugal or the like just after forming the artifi cial filaments and being washed. 7

In testimony whereof I have signed my name to this specification.

BENNO BORZYKOWSKI.