GB450021A - The manufacture of monoazo pigments for the colouring of rubber - Google Patents

Abstract

Monoazo pigment dyes suitable for colouring rubber are made by coupling, with or without the presence of a substratum, a diazo compound of a nitroamine of the formula <FORM:0450021/IV/1> where X = methyl, alkoxy, benzoylamino or chlorine, with a nitroarylamide, other than acetoacetic-2-nitroanilide, having the general formula <FORM:0450021/IV/2> where R = methyl or aryl and Y = H, halogen or methyl. Suitable substrata are barytes, blanc fixe, lithopone or alumina. When compounded with rubber the pigments withstand the usual vulcanizing treatment and do not bleed during the curing process. In examples the following dyes are described: 3-nitro-4-toluidine --> acetoacetic - 4 - nitroanilide (greenish yellow); (2) 4-chloro-2-nitroaniline --> acetoacetic - 3 - nitro - 4 - toluidide (yellow); other components specified are 3-nitro-4-anisidine, 2 - nitro - 4 - benzoylaminoaniline; acetoacetic-3-nitroanilide, acetoacetic - 2 - chloro - 4 - nitroanilide, benzoylacetic - 3 - nitroanilide. Specifications 9252/14,272,580, [both in Class 2 (iii)], and 355,709 are referred to.ALSO:Rubber is coloured in yellow shades by means of the monoazo dyes obtained by coupling a diazo compound of a nitroamine of the formula <FORM:0450021/V/1> where X=methyl, alkoxy, benzoylamino or chlorine, with a nitroarylamide, other than acetoacetic-2-nitroanilide, having the general formula <FORM:0450021/V/2> where R=methyl or aryl and Y=H, CH3 or halogen. The pigments are fast to vulcanization and do not bleed during the curing process.