US2056611A - Method of reeling-off silk cocoons - Google Patents

Description

Patented bet. 3, 1936 UNiTED STATES fzldtaaii PATENT OFFICE Bernard Loewe, Milan, Italy No Drawing.

Application February 27, 1934,

Serial No. 713,139. In Italy March 8, 1933 7 Claims.

This invention relates to the manufacture of silk, and more particularly to an improved method of reeling-off silk cocoons.

It is an object of the present invention to produce a silk filament which is not hygroscopic, does not tend to adhere to the winding means and has an improved strength.

Other objects, and the manner in which they .are attained, will appear from the following description.

In the known methods of spinning silk cocoons in the cold, by which the cocoons, with .or without preliminary treatment with alkaline, neutral, or acid salts or with very weak basic or ammonia solutions, are treated in a solution of alkalies or alkaline earths and then reeled-off in cold water at a temperature of about 30 C. or less, certain dificulties and draw- .backs are incurred inasmuch as the cocoon thread or the composite grege or twisted silk yarn made up of two or more cocoon threads loses elasticity in consequence of the pull exerted thereon between the spinning vessel and the winding device (spool, reel, or the like), and inasmuch as the bast of the threads, which is softened by the previous treatment of the cocoon, becomes so sticky and hygroscopic that the threads tend to adhere to the winding device in spite of the employment of heat in drying. It will be clear that in consequence of these undesirable concomitants the quality of the silk obtained is depreciated.

The present invention obviates the above-mentioned drawbacks. I have found that if the reeled-01f thread as it comes from the spinning vessel and having alkaline reaction, be so treated, before winding, that the bast already softened by the preliminary treatment is caused to coagulate and the alkalinity of the thread neutralized,

then the thread neither tends to adhere to the winding device nor loses the elasticity and strength which can be imparted thereto by effecting the reeling-01f in cold water. This new treatment can be carried out by transferring the thread directly from the spinning vessel into a coagulating and neutralizing bath. Alternatively, a bath of this nature can be provided at a certain distance from the point at which the reeled-01f thread leaves the spinning vessel, and the thread passed therethrough. For reasons of economy this method of drawing the thread through the bath is preferred to that of sprinkling with the coagulating and neutralizing agents or of causing these agents to act upon the thread in a gaseous or vaporized state, although these latter methods of treating the thread after spinning are equally admissible.

- For the coagulating and neutralizing bath there can be employed, in accordance with the invention, very dilute solutions of inorganic and organic acids, such as hydrochloric acid, sulphuric acid, citric acid, and the like, or solutions of inorganic or organic acid salts, such as for example magnesium sulphate, sodium protochloride, alum, ammonium sulphate, and the like, either alone or in conjunction with acids. The concentration of the baths used is Varied according to the alkalinity of the treated cocoons and of the spinning water. When hydrochloric acid is employed as coagulating agent the concentration of the bath will as a rule be considerably less than 1%. To the neutralizing and coagulating baths there may be added emulsified oils, for example sulphonated castor oil, in very slight quantities. 20

The drying of a thread neutralized by passage for instance through an acid bath can be effected not only in a current of hot air but also in a current of cold air at a temperature of about 35 C. or less, or equally in hot and cold air.

Whereas washing of the thread after the last alkaline or alkaline earth bath before reelingoff, or the reeling-off of the pre-treated cocoons in acidulated water has a seriously detrimental effect both asregards ease of reeling-off and also as regards the cohesion of the silk obtained thereby, the treatment of the alkaline thread after reeling-off and before winding, with agents for the coagulation of its bast and for neutralization, results in the obtaining of silk of markedly enhanced quality.

As above mentioned, a silk thread which is reeled-off in ordinary water after treatment in alkaline baths, and which has not been debasted by the preliminary treatment, possesses alkalinity. A thread of this nature, or a composite grege yarn made up of two or more threads of this nature, is caused to pass, for example, after leaving the spinning vessel, between this latter and the winding device, through a bath consisting of a 0.5% solution of hydrochloric acid, to which, if desired, sulphonated castor oil or other emulsified oils are added, preferably drop by drop; the bathing liquid adhering to the thread is then removed, with or with. out mechanical wiping, by a current of hot air or of cold air at a temperature of 35 C. and less. The thread as it leaves the spinning vessel and possessing alkalinity is thus neutralized and dried on its way to the winding device.

I It is to be understood that the present method is not limited to application in conjunction with cold spinning processes, but that the same can be employed whenever the thread possesses alkalinity after spinning.

What I claim is:

1. In the method of reeling-off silk cocoons after treatment thereof in alkaline baths, the step of neutralizing the alkaline thread leaving the spinning vessel, on its way to the winding means, after it has been reeled off, whereby to increase the smoothness, elasticity, flexibility and strength and decrease the hygroscopicity of the produced filament.

2. In the method of reeling-off silk cocoons after treatment in an alkaline bath, the step of neutralizing the thread and coagulating the bast thereof to prevent adhesion to the winding means by passing the unwound, reeled-off thread through an acid bath on its way from the spinning vessel to the winding means.

3. In the method of reeling-off silk cocoons after treatment in an alkaline bath, the step of neutralizing the thread and coagulating the bast on the outer surface thereof to prevent adhesion to the winding means by passing the unwound, reeled-off thread through a. bath of ionized acid salts on its way from the spinning vessel to the winding means.

4. In the method of reeling-off silk cocoons after treatment in an alkaline bath, the steps of passing the reeled-off thread, on its way from the spinning vessel to the winding means, through a neutralizing and bast-coagulating bath, and drying the thread thus treated, in a current of cold air, with previous wiping, before winding.

5. In the method of reeling-off silk cocoons after treatment in an alkaline bath, the steps of passing the reeled-off thread, on its way from the spinning vessel to the winding means, through a neutralizing and bast-coagulating bath containing emulsified oil as an addition.

6. In a method of producing a silk filament from silk cocoons, the steps comprising treating the cocoons in alkaline baths, thereupon reelingoff the alkaline thread, thereafter neutralizing the thread and coagulating the bast on the outer surface thereof by treating the thread in an acidulated bath, and then drying and winding the thread.

'7. In the method of reeling-off silk cocoons after treatment in an alkaline bath, the steps of neutralizing the unwound, reeled-01f thread after leaving the spinning vessel, wiping the neutralized thread, drying the neutralized thread, and then winding the same.

BERNARD LOEWE.