Patent GB-343121-A (GB)
Title: Improvements in the treatment of materials made of or containing cellulose derivatives
IPC: D06M11/45
Filed: 1929-11-06
Abstract: Filaments, threads, yarns, ribbons, or fabrics made of or containing cellulose esters or ethers are treated for the purposes of modifying the lustre, weighting, or raising the safe ironing temperature by the application thereto of fine dispersions or colloidal solutions of white or substantially white inorganic substances.  Suitable substances are oxides of aluminium, titanium, tin, silicon, zinc, cerium, &c., barium carbonate, barium sulphate, zinc sulphide, china clay, bentonite and other substantially white insoluble silicates. The fine dispersions or colloidal solutions may be obtained by mechanical disintegration of the substances in presence of the dispersion medium with or without protective colloids, or by chemical formation of the substances in the dispersion medium, e.g. formation of colloidal alumina by dialysing an aluminium salt or by boiling a solution of aluminium acetate, or by peptization of the substances with acids, alkalies or salts.  The absorption of the substances by the fibres, &c. may be facilitated by arranging that the electric charge of the dispersed particles is of opposite sign to that of the fibres, &c., by heating, or by addition of electrolytes especially such as contain di-, tri-, or poly-valent ions. Swelling agents such as thiocyanates, acetic acid, lactic acid, aromatic sulphonic acids, or phenols may also be used to facilitate the absorption.  The application of the dispersions, &c. may be effected by bath, spraying, or padding treatments, printing, or stencilling.  The following examples are specified. (1) A cellulose acetate yarn or fabric is immersed for 10-30 minutes at about 60 DEG  C. in a bath containing about 5 per cent of finely dispersed titanium oxide; a suitable dispersion is obtained by adding a 5 per cent caustic soda solution to a solution of titanium sulphate of a strength corresponding to 5 per cent of TiO2 while maintaining the temperature at 0-5 DEG  C., separating, washing, draining, and pressing the precipitated hydroxide to a paste containing about 20 per cent of TiO2, stirring into this paste concentrated hydrochloric acid corresponding to 1-2 per cent HCl calculated on the weight of TiO2, heating to 80-100 DEG  C. until it gelatinizes, a further quantity of the acid being added, if desired, to facilitate dispersion, and diluting with water; local application of the sol may be effected by spraying through stencils or printing.  (2) A similar impregnation of or local application to the goods is effected with a fine dispersion of 4-8 per cent of alumina; a suitable dispersion is obtained as described in (1) using aluminium sulphate instead of titanium sulphate.  (3) The goods are immersed in a bath containing a dispersion of alumina obtained by adding aqueous ammonia to a solution of aluminium chloride, washing the precipitate, boiling it with about 200 times its weight of water, and adding gradually N/20 hydrochloric acid corresponding to about 1/20 of the volume of the liquor. (4) A cellulose acetate fabric is delustred by padding or printing with a mixture of bentonite, methylated spirit, gum arabic, phenol or diethylene glycol or a mixture thereof, and water.  Partial saponification of cellulose ester materials with dilute alkali containing finely divided clay, alumina, calcium carbonate, &c. is disclaimed.  The Provisional Specification includes the use of suspensions as well as of fine dispersions and colloidal solutions.