Process of dyeing polyurethane shaped article with water-soluble dyestuffs

摘要

Shaped articles of polyurethanes, e.g. fibres and foams, are dyed in a bath containing an anionic water-soluble dyestuff and either a cationic surfactant or a mixture of amphoteric surfactant and an acid substance. Suitable dyes are direct, acid and reactive dyes. When reactive dyes of the formula are used, where R, R1 and R11 are H, lower alkyl or halogen, Z is a poly-basic acid group and D a dye molecule, the dye is dissolved in water, a caustic alkali, sodium carbonate or sodium triphosphate is added to form the sulphone and the resulting solution is neutralized with an acidic material before being used to dye the article. Suitable cationic surfactants are ammonium salts, alkyl pyridinium halides and alkyl amines. Suitable amphoteric surfactants are those of the betaine type which are used in conjunction with acid substances, e.g. formic, acetic, phosphoric, hydrochloric and sulphuric acids. The dyebath may further contain a non-ionic surfactant. Examples are given.