Patent GB-457933-A (GB)
Title: Improvements in the production of textile threads and fabrics made of or containing cellulose esters or ethers
IPC: D02G1/00
Filed: 1935-06-08
Abstract: A twisted cellulose acetate thread, having no cr<\>zeping power, is subjected to the action of a shrinking agent for the cellulose acetate so as to shrink the thread until it has sufficient twist to impart cr<\>zeping power.  Instead of cellulose acetate thread, that of another cellulose ester or ether such as a formate, propionate, butyrate, nitro-acetate, or aceto-butyrate, or a methyl, ethyl, or benzyl ether, or an ether-ester, may be treated. The final twist after shrinking should not be below about 70--75 turns per inch for threads of 165 denier, and 85--90 turns per inch in the case of threads of 115 denier.  The twist before shrinking may be lower by a fifth, quarter, or third of the final twist.  Preferably, the initial twist is at least 70 per cent of that requisite for cr<\>zeping power.  The shrinking treatment is preferably effected with such agents and under such conditions as would shrink cellulose acetate filaments by 10--30 per cent of their length.  Shrinking agents specified are alcohols, organic acids, including lactic acid, ketones, glycol or poly-glycol ethers, esters such as ethyl lactate, diethyl tartrate, esters of glycols, and esters of glycerol and other polyhydric alcohols, ether-esters of glycols such as the acetate of glycol mono-ethyl ether, cyclic ethers such as dioxane, and methylene ethylene ether, phenols, halogenated hydrocarbons such as dichlorethylene. Latent solvents such as methylene or ethylene chloride, chloroform, tetrachlorethane, ethyl acetate may be used as shrinking agents.  Diluents such as water, glycol, or glycerol, may be used with the shrinking agents.  Aqueous ethyl alcohol, acetone, or dioxane may be used.  Benzene, toluene, xylene, benzine, perchlorethylene, pentachlorethane, hexachlorethane, tetra or deca-hydronaphthalene may be used as diluents.  The twisted threads may be wound on supports permitting shrinkage and then immersed in the shrinking agent, or the threads may be fed through a bath of the agent and wound at a slower rate than the feed rate.  Before winding, the threads may be passed through a drier.  Twisting and shrinking may be effected continuously by having a twisting spindle of the kind in which twist is inserted as the thread is drawn off a rotating package.  The threads to be treated may be obtained by dry or wet spinning methods.  The twist may be inserted in one or more stages and the threads may be treated with water or steam during or between twisting operations. The treated threads may be incorporated in fabrics in any desired manner.  A warp of cellulose acetate threads of low twist may be associated with a weft of the high twist cr<\>zepe threads, pairs of right-hand twist threads alternating with pairs of left hand twist.  The cr<\>zepe effect may be obtained by treatment of the fabrics with hot aqueous liquids such as soap solution. Specifications 277,089, 323,790, [both in Class 2 (ii)], 370,430, 371,461; 386,344, 386,374 and 437,019, [all in Group IX]; 438,584, 438,585, and 438,586; and 438,587, 438,589, 438,590, and 438,591, [all in Group IX], are referred to.