Patent GB-402776-A (GB)
Title: Improvements in the manufacture and treatment of artificial textile materials
IPC: D01F2/28
Filed: 1932-06-07
Abstract: For the stretching of artificial filaments, yarns, films &c. of cellulose acetate or other cellulose esters or ethers, there are used as softening or assisting agents organic di-esters and ether-esters of alkylidene glycols, for example, methylene, ethylidene or propylidene diacetate, methylene or ethylidene dipropionate, ethylidene acetate propionate, methoxymethyl acetate, and a -ethoxyethyl acetate.  The softening agents may be used alone or diluted with water, alcohols, ethers and hydrocarbons, and they may be mixed with other solvents such as the oxanones of Specification 387,686 and the esters and ether-esters of olefine and polyolefine glycols, or with plasticisers; and the softening agent may be applied by spraying, or by passage of the threads &c. over moistened surfaces, or by immersion.  Stretching may be carried out generally according to the methods of Specifications 277,089 and 323,790, [both in Class 2 (ii), Cellulose &c.], that is, on the hanks &c. or on travelling materials; and softening and stretching may be effected continuously with the production of the filaments, for example, in the case of wet spinning the softening agent may be contained in the coagulation bath or in a subsequent treatment bath as described in Specifications 340,324 and 340,437, and the stretch may be assisted by a counter current of liquid as described in Specification 375,424; in the case of dry spinning the softening agent may be applied after the filaments &c. leave the spinning cell or it may be applied during their travel through the cell as by rollers in the manner of Specification 391,443.  In the case of travelling materials, the tension may be applied directly to the softened portion of the material, or it may be applied at a point at which the filaments &c. have been dried and under such conditions that the tension runs back to the softened portion; and resistances may be interposed to prevent the tension running still further back to the unsoftened or incompletely-softened part.  The materials may be subjected to two or more softening treatments of different strengths as described in Specification 392,185.  Stretching may be in stages as described in Specification 370,430, or a number of threads arranged as a wasp may be stretched together in the manner of Specification 371,461. The softening liquid may be removed from the stretched material by washing as with solutions of the solvents, salts, sugars &c. in order to prevent loss of lustre, or with the softening liquid itself as described in Specification 401,679, preferably by washing with solutions of decreasing concentration.  The washed p  materials may be dried under tension.  The materials, after stretching may be subjected to saponification by treatment with aqueous or alcoholic alkaline agents, or with solutions of the latter in glycols, glycerine, &c., or with the addition of lime &c.  Alternatively, after stretchng, the materials may be shrunk, for example, by the process described in Specification 389,823. The stretching may be applied locally to the threads &c. as by the local application of softening agent or by the intermittent application of the stretching tension; and the intermittently-stretched materials may be treated so as to give differential saponification effects as described in Specification 400,938, or differential lustre effects as described in Specification 400,946.  Specifications 402,104 and 402,106 also are referred to.