GB461042A - Process for colouring paper - Google Patents

Abstract

Paper is coloured by grounding it in an alkaline bath with an arylide of a b -keto-carboxylic acid or of an o-oxyarylcarboxylic acid, which arylide is free from groups which lend solubility, such as sulpho-groups, and the grounded paper, without being dried, is then passed through a solution of a non-sulphonated diazo compound. According to the examples: (1) paper is foularded with a grounding bath containing diacetoacetyltolidine, turkey red oil and caustic soda and developed with diazotized o-chloraniline containing aluminium sulphate (yellow); (2) paper is grounded as in (1) with the o-anisidide of 2 : 3-oxynaphthoic acid containing formaldehyde in addition and developed with diazotized 4 : 4<1>-dichloro-2-amino-1 : 1<1>-diphenylether (red). Other components specified are arylides of pyrazolone or arylpyrazolone carboxylic acids, arylides of terephthaloyl-bis-acetic acid, the anilide, p-toluidide, p-chloranilide, a - or b -naphthylamide of 2 : 3-oxynaphthoic acid, the anilide of 2-oxyanthracene-3-carboxylic acid, the anilide of 2 : 3-oxycarbazole carboxylic acid, the arylides of 2 : 3-oxynaphthocarbazolecarboxylic acids or the arylides from cresotinic acid (2 mols.) and benzidine, dianisidine or tolidine; 2 : 5-dichloraniline, o-nitroaniline, 4-chloro-o-nitroaniline, 4-methyl-o-nitroaniline, 4- or 5-chloro-o-toluidine, 5-nitro-o-anisidine, dianisidine, diethylamide of 1-amino-2-methoxy-5-benzenesulphonic acid, 5 - nitro - o - toluidine, aminoazo compounds, e.g. aminoazobenzene, 4 - amino - 3 : 2<1> - dimethylazobenzene, or 4-amino - 5 - methoxyazobenzene, 4 - (4<1>-methyl)-phenoxyacetylamino - 2 : 5 - dimethoxy- or diethoxy - 1 - aminobenzene, 4 - benzoylamino-2 : 5 - dimethoxy- or diethoxy - 1 - amino-benzene. The diazo solutions may be buffered with sodium acetate or bicarbonate, or alkali phosphate.