GB372224A - Process for producing fast colour reserves by means of ester salts of leuco vat dyestuffs without steaming - Google Patents

Abstract

The process of the parent Specification is modified by adding aluminium chlorate to the printing pastes in addition to the salt of acid reaction used as a reserve, the ester salts of the leuco vat dyestuffs being developed by a drying operation before producing the ground colour by treatment with a diazo solution. In examples, goods impregnated with 2 : 3-oxynaphthoic anilide are printed, after drying, with pastes containing the sodium salts of the disulphuric esters of leuco-3 : 4 : 8 : 9-dibenzpyrene-5 : 10-quinone (Specifications 205,502, 220,304 or 222,125, [all in Class 2 (iii), Dyes &c.]), leuco-5 : 7 : 5<1> : 7<1>-tetrabromindigo, leucodimethoxydibenzanthrone, the leuco vat dye from isatin-anilide and 1-methyl-7 : 8-oxybenzocarbazole, or leuco-6 : 5<1> : 7<1>-tribromindigo, thiodiglycol, starch tragacanth, aluminium chlorate and aluminium sulphate (or zinc sulphate), with or without oxalic acid, dried, padded with a solution of diazotized 4-amino-4<1>-methoxydiphenylamine, and finally treated in a bath containing hydrochloric acid to decompose excess of the diazo compound. Yellow, bright blue, green, grey to black, and violet effects on a dark blue ground are obtained. Specification 356,577 also is referred to.