Patent GB-336217-A (GB)
Title: Improvements in or relating to the manufacture or treatment of materials made of or containing organic derivatives of cellulose
IPC: D01F2/28
Filed: 1929-03-28
Abstract: 336,217. Dreyfus, H. March 28, 1929. Yarns and threads, treating with liquids, gases and vapours.-The tensile strength, extensibility and elasticity of filaments, threads and other products made of or containing cellulose acetate or ether esters or ethers of cellulose, is increased by treatment with neutral organic solvents in relatively high concentration, in particular, so that a superficial filming or even plasticizing of the materials occurs. The treatment is applied to materials in their finished condition whether made by dry or wet methods, or continuously with the production of the materials by dry or semidry processes. The materials being treated may be placed under tension only sufficient to prevent shrinkage; or shrinkage may be permitted to take place; or the materials may be stretched during or after the treatment. Suitable solvents are acetone, diacetone alcohol, mono- or di-ethers of olefine glycols or poly-olefine glycols, diethyl tartrate, ethyl lactate, phenols and mono- or diacetins; and the solvent is preferably diluted with water, benzene or other non-solvent, the best results being obtained with a relatively non- volatile solvent diluted with a non-solvent. A relatively high concentration of the solvent may be obtained by the use of a more dilute solution of a non-volatile, solvent in a volatile diluent, and permitting the latter to evaporate. Preferably the solvent is such that it need not be washed out of the materials although the latter may be first washed with a solution of the solvent of lower concentration. The solvent may be applied by spraying, by passage through a bath, or by mechanical impregnation as in a padding mangle. When the treatment is applied continuously with the production of the threads, the filaments leaving the spinning cell may be passed through a reed or comb immersed in the solvent; or the filaments while still laden with residual solvent may be treated with solvent according to the methods of Specification 327,740, [Class 2 (ii), Cellulose &c.], for example, by passage in contact with a wick, care being taken to prevent mutual contact of the filaments, the use of a line of spinning jets contributing to this end. During the treatment the lustre of the materials mav be modified; in general the lustre is greater as the concentration of the solvent is higher. If products of reduced lustre are required, the manufacture may be designed so as to produce such materials as by employing the processes of Specifications 328,247; 333,504. [Class 2 (ii). Cellulose &c.]; and 334,563, or the materials may be after-treated to produce such products. In examples, filaments of cellulose acetate after being dry spun are treated with 45-55 per cent aqueous of diacetone alcohol or with 45 per cent aqueous ethyl lactate or with 50 per cent alcoholic diacetone alcohol; hanks of cellulose, acetate siiare sprayed with an aqueous solution of 30 per cent diacetone alcohol and 15 per cent acetone, and subsequently washed with aqueous diacetonealcohol. Specifications 250,265. 259,899, 277,089. 280,990, 281,084, 284,798; 302,361, [Class 142 (iv), Woven fabrics &c.] ; 308,173, and 323,790 also are referred to. According to the Provisianal Specifications strong swelling agents may be employed for the treatment.