GB428767A - Improvements in the dyeing of cellulose acetate artificial silk - Google Patents

Abstract

Cellulose acetate, dyeing; dye mixtures.--The dyeing of cellulose acetate artificial silk is effected with the use of a dyestuff preparation, brought into a state of fine dispersion in the usual manner, comprising two or more dyestuffs of the general formula <FORM:0428767/IV/1> (wherein R1 represents H or alkyl and R2 represents aryl of the benzene series) which dye similar shades, at least one having only a weak or moderate affinity for the artificial silk. The dyestuff preparation may be obtained by using a mixture of suitable components for the production of the dyestuffs, or by dissolving the individual dyestuffs in a common solvent and precipitating the mixture in a finely divided state, or by finely grinding a mixture of the dyestuffs, or by adding the finely divided dyestuffs to the same dyebath. The following examples are specified. (1) 1-Amino-4-anilinoanthraquinone and 1-amino-4-p-toluidinoanthraquinone are dissolved in conc. sulphuric acid at 0--10 DEG C., the solution is poured upon ice and filtered and the residue is washed until neutral and ground with a dispersing agent to obtain a preparation which dyes the artificial silk an intense blue. (2) 1-Amino-4-anilinoanthraquinone and 1 - amino - 4 - p - toluidinoanthraquinone are stirred into a soap solution at about 50 DEG C. and diluted with lukewarm water to obtain a bath in which the artificial silk is dyed an intense blue by treatment for \ba3/4\be hour during which the temperature is raised to 75--80 DEG C. and further treatment for \ba3/4\be hour at this temperature, followed by rinsing and drying. Specification 219,349, [Class 15 (ii)], is referred to. The Specification as open to inspection under Sect. 91 comprises also (a) anaadditional example in which a mixture of 1-amino-4-(4<1>-amino) phenylaminoanthraquinone and 1-methylamino-4-(4<1>-oxy) phenyl aminoanthraquinone is used; (b) the use of any mixture of two or more homologues, isomeric or analogous dyestuffs suitable for dyeing the artificial silk, at least one having a poor affinity for the material; the dyestuffs may be, for example, aminoanthraquinones in general or azo dyestuffs and the use of mixtures of certain dialkylaminomonoazo dyestuffs is claimed in Specification 428,841. This subject-matter does not appear in the Specification as accepted.