Patent GB-407357-A (GB)
Title: Improvements in or relating to the production of yarns comprising artificial filaments
IPC: D06M13/12
Filed: 1932-07-08
Abstract: Yarns, treating with liquids.--Spun yarn, i.e. staple fibre yarn, of good extension is produced from continuous artificial filaments of organic derivatives of cellulose (other than such derivatives as are soluble in water or dilute alkali) by severing at least some of the filaments and subjecting them to controlled shrinking treatment such that the reduction in length is of the order of 5--30 per cent.  The process of Specification 388,796 is disclaimed.  The yarns so obtained are especially suitable for manufacture of knitted fabrics. The controlled shrinking treatment may be applied in the production of spun yarns from artificial filaments by the processes of Specifications 397,137, 397,138, 399,838, 403,738, or 403,739, [all in Group IX].  The shrinking may be effected before or after the severing operation and before or after the application of a part or the whole of the twist.  Specified cellulose derivatives are the acetate, formate, propionate, butyrate and nitroacetate, ethyl cellulose, benzyl cellulose, ethyl cellulose acetate and oxyethyl cellulose acetate and other fibres, e.g. silk, wool or cotton may be associated therewith.  Suitable shrinking agents are solvents or swelling agents, such as acetic, formic and lactic acids, diacetone alcohol, acetone, the mono- and di-methyl ethers of ethylene glycol, glycol mono-acetate, methyl glycol mono-acetate, dioxane, methylene ethylene dioxide, homologues and substitution products of these cyclic ethers, mono-, di- and tri-acetins, ethyl lactate and diethyl tartrate and latent solvents, such as methylene chloride, ethylene chloride, chloroform, tetrachlorethane and ethyl acetate.  To effect the controlled shrinkage most the above agents or mixtures thereof require dilution with another liquid, e.g. water, glycol, glycerol, benzene, toluene, xylene, benzine, petrol ether, kerosene, hexahydrobenzene, tetra- or deca-hydronaphthalene, carbon tetrachloride, trichlorethylene or perchlorethylene.  The control may also be effected by adjusting the temperature or duration of the treatment or the tension, if any applied to the material.  The shrinking agents may be applied to loose yarns, e.g. in the form of hanks or to yarns on resilient bobbins, swifts or in other package form or to yarns being wound from one package to another package winding more slowly, and such agents may be subsequently removed, e.g. by evaporation or by washing with water or other suitable solvent.  The following examples are specified: (1) a low twist cellulose acetate spun yarn is shrunk by treatment for 5 minutes at room temperature in an acetone-water mixture containing 40 per cent by volume of acetone, the bath ratio being 100 : 1; (2) a low twist cellulose acetate spun yarn is treated for 5 minutes in a mixture comprising by volume 60 parts of methylene chloride and 40 parts of benzene; (3) high twist cellulose acetate spun yarns are treated as in (1) and (2); (4) a low twist cellulose acetate spun yarn is passed for 30 seconds at room temperature through a 50 per cent acetone-water mixture.  Specification 165,164, [Class 2 (ii)], also is referred to.