GB560747A - Improvements in vat-dyestuff preparations for printing textiles - Google Patents

Abstract

Preparations for use in producing prints fast to washing and rubbing on textile fabrics, especially of cotton, regenerated cellulose or natural silk, are obtained by dissolving a cellulose derivative, an ester salt of a leuco vat dyestuff and an oxidising agent in a solvent (containing in some cases a small proportion of water) comprising an aliphatic monohydric or polyhydric alcohol or an ether thereof or an aliphatic hydroxycarboxylic acid or an ester thereof or thiodiglycol or a mixture of such solvents, and treating the solution with an acid, preferably organic, whereby the vat dyestuff in a finely divided state is formed within the preparation. Urea and/or a softening agent such as triphenyl or tricresyl phosphate may, advantageously, be incorporated. Specified cellulose derivatives are nitrocellulose, acetylcellulose and ethylcellulose, specified solvents are methyl, ethyl and butyl alcohols, glycol monomethyl and monoethyl ethers, diethylene glycol mono- and di-ethyl ethers, dioxane, methyl lactate, diethyl tartrate and thiodiglycol, and specified oxidising agents are chromates and nitrates. In examples printing pastes are obtained as follows: (1) a solution of the sodium salt of the sulphuric acid ester of leuco - 6 - ethoxy - 41 - methyl - 61 - chloro - thioindigo in a mixture of glycol monoethyl ether, thiodiglycol and water is stirred into a lacquer containing nitrocellulose, butyl alcohol, butyl acetate, ethyl lactate and ethyl alcohol, with or without triphenyl phosphate and to the mixture are added urea, butyl alcohol and an aqueous solution of sodium nitrite, followed by oxalic acid in a mixture of glycol monoethyl ether and dioxane, and the whole is stirred for 1 hour at room temperature and then for 4 to 5 hours at 30 DEG C. and diluted with butyl alcohol and glycol monoethyl ether; (2) the leuco ester salt in (1) is replaced by the sodium salt of the sulphuric acid ester of leuco-3 : 4 : 8 : 9-dibenzpyrene-5 : 10-quinone and after the stirring for 1 hour, butyl alcohol is added, the stirring is then continued for 4 hours at 30 DEG C. and the final dilution is with glycol monoethyl ether; (3) the leuco ester salt in (1) is replaced by the sodium salt of the sulphuric acid ester of the vat dyestuff obtainable by heating 1 : 11-dianthraquinonyl-111 : 411-diaminoanthraquinone with aluminium chloride in pyridine; (4) to a solution of the sodium salt of the sulphuric acid ester of leuco-3 : 4 : 8 : 9-dibenzpyrene-5 : 10-quinone in a mixture of glycol monoethyl ether, thiodiglycol and water are added a lacquer as in (1), urea, butyl alcohol, sodium bichromate, water, a mixture of glycol monoethyl ether and dioxane, and oxalic acid.