GB500960A - Improvements in the treatment of textile materials - Google Patents

Abstract

500,960. Artificial silk &c. ; dyeing processes. MONCRIEFF, R. W., and GREASLEY, T. Aug. 17, 1937, No. 22594. [Classes 2 (ii) and 15 (ii)] Cellulose ester products made by esterifying formed filaments, yarns, foils, films, and similar materials having a basis of organic derivatives of cellulose so that in the products 2À75 or more hydroxyl groups per C6 cellulose unit are esterified or in part esterified and in part etherified, are coloured by applying a dyestuff, or compound capable of conversion to a dyestuff on the material, while the material is in a swollen state due to the action of a liquid mixture containing a water-soluble swelling agent for acetone-soluble cellulose acetate and a hydrophylic liquid of little or no swelling power for acetone-soluble cellulose acetate. The liquid mixture is such that under the conditions employed textile materials of filaments spun from solutions of acetone-soluble cellulose acetate and not subjected to further chemical treatment would be dissolved, shrunk to a considerable extent, or rendered so soft that substantial stretching would be unavoidable when the materials were handled. The process is applicable to materials which have been stretched in steam or hot water prior to the esterification. Acetic, formic, lactic, or tartaric acid, or methyl formate, methyl acetate, ethyl formate, monoacetine, acetone, methylethyl ketone, or a thiocyanate, may be used as swelling agent. The non-solvent liquid may be methyl, ethyl, n- or iso-propyl alcohol,orwater. Acetic acid may be used in concentrations of 40-60 per cent or in the case of stretched products the concentration may be 70-90 per cent. Acetone may be used in a concentration of 50-60 per cent in water. Treatment with swelling mixture may be effected prior to or at the same time as application of dyestuff or dye-forming substance. The swelling liquid may be removed before applying the dye. Direct dyeing water-insoluble dyes of the azo, aminoanthraquinone, and nitro diarylamine series may be used. Vat dyes may be applied as leuco compounds or salts or esters of leuco compounds. A leuco compound may be dissolved in water or iso-propyl alcohol containing a reducing agent and acetic acid. The material is dyed in this liquid and the colour produced by oxidation. In an example, a cellulose acetate fabric which has undergone further acetylation is washed, immersed in a strong aqueous solution of acetic acid, washed, dyed with 1- 4- di-(methylamino)anthraquinone, turkey red oil, xylene, sodium carbonate and water, washed and dried. A blue-shade is obtained. The dye-bath may be heated. In other examples, cellulose acetate yarns which have undergone further acetylation are swollen with acetic acid solution and dyed with Caledon Jade Green, or Soledon Blue, or treated with a paste of Naphthol AS.DB, turkey red oil, caustic soda and water, and then with the diazo compound from Fast Red Base T.R. In another example, the yarns are swollen and dyed at the same time in a bath comprising Soledon Blue 4B.C.S., soluble zinc formaldehyde sulphoxylate, and aqueous acetic acid. Specifications 448,816, 448,817, and 448,917 are referred to.