Patent GB-404933-A (GB)
Title: Improvements in the production or treatment of artificial filaments, threads, and the like
IPC: D01F2/28
Filed: 1932-06-16
Abstract: Artificial filaments, threads, ribbons and other textile materials, having a basis of organic derivatives of cellulose, and which contain a finely divided saccharose or organic derivative thereof, (other than cellulose or a cellulose derivative) which is insoluble in the common solvents for the organic derivative of cellulose, are treated with hot water or a hot aqueous medium, to delustre them.  The textile materials may be obtained by extruding solutions of organic derivatives of cellulose containing finely divided saccharoses or organic derivatives thereof into setting media.  Saccharoses specified include cereal starches such as those of maize, rye, barley, wheat, potato, arrowroot, sago, rice and beetroot seed, soluble starch, glycogen, lichenine, inulin, dextrin, sucrose and glucose, and their organic derivatives include feculose and the acetates, laurates, palmitates, stearates, benzoates and other esters which are insoluble in the common solvents for the cellulose derivative employed.  The textile materials may be of cellulose formate, acetate, propionate, butyrate, nitroacetate and other esters or mixed esters, of ethyl, butyl and benzyl cellulose or other ethers or mixed ethers, or mixed cellulose ether-esters, e.g. ethyl cellulose acetate and oxyethyl cellulose acetate.  The saccharoses may be incorporated in the spinning solutions and are preferably incompatible with the base of the artificial materials and are preferably dissolved or easily swollen by hot water or hot aqueous media, e.g. soap solutions.  When starches are used they may be boiled or air dried but are preferably dried in vacuum below 50 to 60 DEG  C. to avoid gelatinisation.  When wet spinning processes are employed it is desirable that the coagulating bath should not exert pronounced solvent action upon the delustring substance. The delustring substance is preferably in a state of fine subdivision which may be obtained by adding a solution of it to a spinning solution in which it is insoluble, e.g. an aqueous solution of soluble starch to an acetone solution of cellulose acetate or by grinding.  The particle size may be up to 0.006 mm. diameter but preferably not more than 0.003 mm., and especially between 0.001 and 0.002 mm.  The grinding operation may be dry or wet and in the latter case dispersing agents such as turkey red oil, oleic acid, linseed oil, olive oil or the like may be present.  The proportion of delustring substance may be up to 10 per cent or more but is preferably from 2 to 5 per cent.  The treatment with the hot aqueous medium may be obtained by scouring the treated materials, e.g. with soap solution at 70 DEG  to 85 DEG  C. or during dyeing with S.R.A. colours from soap baths.  The delustring substance may be chosen so that it causes scorching of the material at a temperature below that at which the cellulose derivative begins to melt, as described in Specification 352,058. Other delustring agents such as titanium dioxide, barium sulphate, calcium sulphate and china clay and a small proportion, e.g. 1 to 2 per cent of the delustring substance, of a black or dark coloured substance may also be present.  The materials may be netted, woven or knitted, or associated with normal filaments, or with fibres of other materials such as cotton, wool, natural silk and the like.  In examples (1) a suspension of maize or rice starch in acetone is ground and added to an acetone solution of cellulose acetate, which is then spun.  A fabric knitted therefrom is treated with a dilute soap solution at 80 DEG  C. for one hour; (2) a suspension of starch or feculose in acetone is ground and added to an acetone solution of cellulose acetate which is then spun.  A fabric woven therefrom is dyed from a soap bath at 75 DEG  to 80 DEG  C.; (3) dextrose is incorporated as in (1) the spun yarn being dyed at 80 DEG  C. with p-amino-benzene-azo-a -naphthylamine from a soap bath, followed by diazotisation and development with b -oxynaphthoic acid. The Provisional Specification describes also delustring obtained by incorporating finely divided saccharides or their derivatives in filaments &c., including those of regenerated cellulose, either before or after their formation, without subsequent treatment with aqueous media, and refers to Specifications 344,510 and 346,678.