Patent GB-630359-A (GB)
Title: Improvements relating to the manufacture of organic pigments and moulding powders
IPC: D06P1/22
Filed: 1947-10-08
Abstract: Pigments and moulding powders are made by treating a finely-divided polyvinyl benzal prepared as in the parent Specification with an alkali salt of a coupling component, washing, and thereafter treating with a diazonium salt derived from an aromatic base having no water-solubilizing substituent. Any coupling component possessing the group <FORM:0630359/IV (a)/1> and devoid of water-solubilizing substituents may be used, particularly the Naphthols AS.  The polyvinyl benzal is preferably one prepared from an aromatic aldehyde of the benzene or naphthalene series and polyvinyl alcohol in which the molecular ratio of aldehyde to alcohol is between 0.1 : 1.0 and 0.8 : 1.0. The polyvinyl alcohol used may contain ester or aliphatic acetal groups provided that it is still water-soluble, and the aromatic aldehyde may contain substituents such as chloro- and nitro groups.  In a modification, the diazonium salt is converted to an isodiazotate and applied to the polyvinyl benzal simultaneously with the coupling component and the dyestuff developed by subsequent acidification.  In examples, partial polyvinyl benzal in finely-divided form is treated with: (1) 2-naphthol, caustic soda and sodium ricinoleate and then with diazotized 4-nitro-2-methoxy-aniline; (2) 2-hydroxy-3-naphthoic acid anilide, caustic soda and sodium sulphoricinoleate and then with diazotized 4-chloro-2-methyl-aniline or diazotized 2-chloro-5 - trifluoromethyl - aniline; (3) 2 - hydroxy - 3-naphthoic acid anilide as in (2) and then with 4-nitro-2-methyl-aniline; (4) the sodium salt of 2-hydroxy-3-naphthoic acid p-anisidide and then with diazotized 4-nitro-2-methoxy-aniline; (5) the sodium salt of 2-hydroxy-3-naphthoic acid o-toluidide and then with diazotized 2,5-diethoxy-4-benzoylamino-aniline or 2-methoxy-5 - methyl - 4 - benzoylamino - aniline; (6) the sodium salt of 2-hydroxy-3-naphthoic acid anilide and then with diazotized 3,31-dimethyl-4,41-diamino-diphenyl or 4-(41-nitrobenzene-azo)-2,5-dimethoxy-aniline; (7) diacetoacetic acid-o-toluidide and then with diazotized 2-methoxy-aniline; (8) a mixture of 2-hydroxy-3-naphthoic acid anilide and the sodium derivative of 2,5-dichlorobenzene diazonium hydroxide and then developed with formic acid; (9) 2,2 - dihydroxy - 5,51 - dimethyl - diphenyl - methane and then with diazotized 2,51-dichloroaniline; (10) 2-hydroxycarbazole-3-carboxylic acid-p-chloroanilide and then with diazotized 4 - nitro - 2,2 - methoxy - aniline; and (11) 2 - hydroxy -3-naphthoic acid-p-aniside and then with diazotized 5-nitro-2-amino-toluene.ALSO:Pigments are made by treating a finely-divided polyvinyl benzal prepared as in the parent Specification with an alkali salt of a coupling component, washing, and thereafter treating with a diazonium salt derived from an aromatic base having no water-solubilizing substituent.  Any coupling component possessing the group <FORM:0630359/IV (c)/1> and devoid of water-solubilizing substituents may be used, particularly the Naphthols AS.  The polyvinyl benzal is preferably one prepared from an aromatic aldehyde of the benzene or naphthalene series and polyvinyl alcohol in which the molecular ratio of aldehyde to alcohol is between 0.1 : 1.0 and 0.8 : 1.0.  The polyvinyl alcohol used may contain ester or aliphatic acetal groups provided that it is still water-soluble, and the aromatic aldehyde may contain substituents such as chloro- and nitro-groups.  In a modification, the diazonium salt is converted to an isodiazotate and applied to the polyvinyl benzal simultaneously with the coupling component and the dyestuff developed by subsequent acidification.  In examples, partial polyvinyl benzal in finely divided form is treated with (1) 2-naphthol, caustic soda and sodium ricinoleate and then with diazotized 4 - nitro - 2 - methoxy - aniline; (2) 2 - hydroxy 3-naphthoic acid anilide, caustic soda and sodium sulphoricinoleate and then with diazotized 4 - chloro - 2 - methyl - aniline or diazotized 2 - chloro - 5 - trifluoromethyl - aniline; (3) 2-hydroxy-3-naphthoic acid anilide as in (2) and then with 4-nitro-methyl-aniline; (4) the sodium salt of 2-hydroxy-3-naphthoic acid p-anisidide and then with diazotized 4-nitro-2-methoxy-aniline; (5) the sodium salt of 2-hydroxy-3-naphthoic acid o-toluidide and then with diazotized 2,5-diethoxy-4-benzoylamino - aniline or 2 - methoxy - 5 - methyl - 4-benzoylaminoaniline; (6) the sodium salt of 2-hydroxy-3-naphthoic acid anilide and then with diazotized 3,31-dimethyl-4,41-diamino-diphenyl or 4 - (41 - nitrobenzeneazo) - 2,5-dimethoxy-aniline; (7) diacetoacetic acid-o-tolidide and then with diazotized 2-methoxyaniline; (8) a mixture of 2-hydroxy-3-naphthoic acid anilide and the sodium derivative of 2,5-dichlorobenzene diazonium hydroxide and then developed with formic acid; (9) 2,21-dihydroxy-5,51-dimethyl-diphenyl-methane and then with diazotized 2,51 - dichloroaniline; (10) 2-hydroxycarbazole - 3 - carboxylic acid - p-chloroanilide and then with diazotized 4-nitro-2-methoxy - aniline, and (11) 2 - hydroxy - 3-naphthoic acid-p-anisidide and then with diazotized 5-nitro-2-amino-toluene.