Patent GB-346678-A (GB)
Title: Improvements in the production of artificial filaments, threads, ribbons and the like and in products resulting therefrom
IPC: D01F2/28
Filed: 1929-10-10
Abstract: Cellulose esters and ethers.-Artificial filaments, threads, yarns, ribbons, films, &c., of cellulose or cellulose derivatives are given a reduced, subdued or modified lustre by distributing therein fine particles of a white or substantially white organic substance which does not melt below about 200 DEG  C.  This substance is preferably insoluble in water, dilute acids and alkalies and the ordinary organic solvents.  Best results are obtained by means of organic substances which do not melt below 240-260 DEG  C. or even 290 or 300 DEG  C.  Examples of such substances are the acidyl and diacidyl derivatives of benzidine and like diamino-diphenyl bases, e.g. acetyl benzidine, dibenzoyl benzidine and diacetyl tolidine; sym-a -dinaphthyl urea, condensation products of urea or thiourea with diphenyl bases, e.g. carbo benzidine, thiocarbobenzidine, 4, 41-diureido-diphenyl, 4, 41-dithioureido diphenyl, diphenyl diureido diphenyl; b -tetranaphthyl urea, b -dinaphthyl-oxamide, succinic a -naphthalide, p-nitrophenylphthalimide, anthraquinone, 2, 6-dichloranthraquinone, acenaphthenequinone.  Substances of somewhat lower melting-point are anthracene, carbazole, sym-a -dinaphthyl thiourea and diphenyl oxamide.  The substances are preferably incorporated by way of the spinning solution particularly for cellulose derivatives spun from solutions in organic solvents, e.g. esters such as cellulose acetate, formate, propionate and butyrate and nitrocellulose; and ethers such as methyl, ethyl, or benzyl cellulose.  The substances may be dispersed in the spinning solution by grinding in the presence of the solvent or spinning solution or a portion thereof, or after grinding dry or in the presence of liquids and may be worked with the spinning solution in any suitable way. Dispersion may be improved by small proportions of dispersators and/or protective colloids, e.g. Turkey red oil, or oils &e. e.g. oleic acid, linseed or olive oil.  To enable the substances to pass the filters and spinning nozzles, a particle size of ,003 mm. is usually sufficient but particle sizes up to ,006 may be employed; to obtain maximum modification of lustre the particle size should preferably be below ,003 mm. e.g. down to ,0001-,0005 mm.  The particles are preferably graded to obtain uniform size e.g. by a cyclone separator &c.  The substance may be precipitated from solution and such precipitation may be effected in the spinning solution.  In some cases the substance may be formed in the spinning solution, e.g. leuco anthraquinone or leuco compounds of anthraquinone derivatives may be dissolved in a suitable organic solvent and oxidized to form a fine suspension or dispersion.  The organic substance may also be formed in the presence of the cellulose acetate or other base e.g. it may be formed in the esterification mixture before or after dispersing and before precipitation of the acetate &c.  Where the organic substance is substantially insoluble in the acetate or other base, the addition may be of the order of 1/2 -1 or 2 per cent relative to the base; but lower or higher quantities may be employed e.g. 5-10 per cent.  A small proportion of a black or dark-coloured substance, organic or inorganic, may also be added, e.g. about 1-2 per cent of a black or dark organic colouring matter may be added to the white or substantially white organic substance. The spinning solutions may be spun by dry or wet methods.  Novel effects may be produced by twisting, weaving, knitting, &c. the filaments of modified lustre with normal lustrous filaments of cellulose acetate or other artificial silks or fibres or with cotton, wool, &c.  Novel yarns or threads containing both filaments of modified and normal lustre may be produced by twisting together dull filaments from one spinning nozzle with normal filaments from another.  Monofil threads may be produced by uniting a number of filaments of reduced lustre as by the processes of Specifications 326,461 and 326,462, [both in Class 2 (ii), Cellulose &c.].  The delustring effect may be enhanced by subjecting the threads to delustring treatment as described in Specifications 328,247, 333,504, and 334,195, [all in Class 2 (ii), Cellulose &c.].  The process is particularly applicable to the production of threads &c. from solutions of cellulose acetate, especially by the dry spinning method; but it may be used with solutions of viscose or other bases of the cellulosic type.  Specifications 316,169 and 316,638, [both in Class 2 (ii), Cellulose &c.], also are referred to.