GB452142A - Manufacture of azo-dyestuffs on animal fibres - Google Patents

Abstract

Azo dyes, forming on the material.--In the production of water-insoluble azo dyes upon animal fibres or mixtures thereof with cellulose fibres, the grounding operation is effected by impregnating the fibres with an alkaline solution at 45--60 DEG C. of an arylide of an o-oxyarylcarboxylic acid containing formaldehyde and containing, instead of the excess of caustic alkali necessary for the stabilization, sodium carbonate in a concentration of at least 2 grams per litre or an equivalent amount of another inorganic salt of alkaline reaction, e.g. sodium silicate, pyrophosphate or borate. The intensity of the dyeing may be increased by incorporating neutral salts, e.g. Glauber salt or sodium chloride, in the grounding liquor. The following examples are specified: (1) Wool yarn is dyed an even vivid red by grounding for \ba3/4\be hour in a liquor at 55--60 DEG C. containing specified amounts of 1 - (2<1> : 3<1>-oxynaphthoylamino) - 2 - methyl-4-chlorobenzene, formaldehyde, caustic soda, oleylmethyltaurine and sodium pyrophosphate, silicate or carbonate, squeezing and developing for \ba3/4\be hour in a solution containing the hydrochloride of 1-amino-2-methyl-4-chlorobenzene, hydrochloric acid, sodium nitrite and the product of reaction of ethylene oxide (20 mols.) with octodecyl alcohol (1 mol.), the whole being neutralized with sodium acetate and then acidified with acetic acid; (2) Slubbing consisting of equal amounts of wool and viscose artificial silk staple fibre is dyed an intense scarlet red by grounding and squeezing as in (1) and developing in a similar solution containing, as diazo component, 1-amino-2-methyl 3-chlorobenzene.