Disazo Pigments Containing Acylamino Groups

In the examples which follow the parts, unless otherwise stated, denote parts by weight and the percentages denote percentages by weight.

47.2 parts of 1-amino-2-chloro-5-methoxy-4-acetylaminobenzene are dissolved in 1,500 parts by volume of glacial acetic acid at room temperature. The light yellow solution is stirred with 60 parts by volume of concentrated hydrochloric acid, the mixture is cooled to 6.degree. C, 60 parts by volume of 4N sodium nitrite solution are added dropwise over the course of 10 minutes and the resulting diazo solution is clarified by filtration. The filtrate is brought to pH 4 by addition of 50 parts of 60% strength sodium acetate.

At the same time, 34 parts of 2-methyoxy-5-chloro-1,4-bis-acetoacetylaminobenzene are dissolved in 2,000 parts of water by addition of 30 parts by volume of 40% strength sodium hydroxide solution. After addition of 2 parts of kieselguhr the resulting suspension is clarified by filtration and the residue is rinsed with 70 parts by volume of water. A clear light yellow solution is thus obtained, to which the diazo solution is added dropwise at 5.degree. C over the course of 20 minutes. This produces a yellow precipitate. The suspension obtained is heated to 75.degree. C over the course of one hour and filtered hot. The residue is washed until free from salt and dried in vacuo at 60.degree. C. 78 parts, corresponding to 97% of theory, of a yellow pigment of the formula ##STR8## are obtained.

If this pigment is after-treated in dimethylformamide (one hour at 140.degree. C) and milled into polyvinyl chloride, fast yellow colourations are obtained.

The table which follows describes further colorants which are obtained by coupling the diazotized bases of Column I with the bis-acetoacetic acid arylides of the diamines of Column II. Column III indicates the colour shade of a PVC film coloured with 0.2% of this pigment.

2 g of the pigment prepared according to Example 1 are ground with 36 g of hydrated aluminium oxide, 60 g of a linseed oil varnish of medium viscosity and 2 g of cobalt linoleate on a triple roll mill. The yellow prints produced with the resulting colour paste are deeply coloured and have outstanding fastness to light.

0.6 g of the pigment prepared according to Example 1 are mixed with 67 g of polyvinyl chloride, 33 g of dioctyl phthalate, 2 g of dibutyl-tin dilaurate and 2 g of titanium dioxide and converted to a thin film on a roll mill over the course of 15 minutes at 160.degree. C. The yellow colouration thus produced is deep and fast to migration, heat and light.

10 g of titanium dioxide and 2 g of the pigment prepared according to Example 1 are ground with 88 g of a mixture of 26.4 g of coconut alkyd resin, 24.0 g of melamineformaldehyde resin (50% solids content), 8.8 g of ethylene glycol monomethyl ester and 28.8 g of xylene for 48 hours in a ball mill.

If this lacquer is sprayed onto an aluminium foil, predried for 30 minutes at room temperature and then stoved for 30 minutes at 120.degree. C, a yellow lacquering is obtained, which has good depth of colour and is distinguished by very good fastness to overlacquering, light and weathering.

3.2 parts of 1-amino-4-acetylamino-benzene and 3.1 parts of 2,5-dimethyl-1,4-bis-acetoacetylamino-benzene are dissolved in 200 parts of dichlorobenzene and 50 parts of glacial acetic acid at 50.degree. C. After cooling to room temperature, 2.5 parts of tert.-butyl nitrite in 100 ml of dichlorobenzene are added dropwise over the course of 15 minutes, during which the temperature rises to 40.degree. C and the pigment formation starts.

The mixture is then stirred for 2 hours at 40.degree.-50.degree. C and 18 hours at 103.degree.-140.degree. C. The colorant assumes a uniformly crystalline form. Orange crystalline aggregates of 10 - 20 .mu. length are detectable under the microscope. The produce is filtered off at 140.degree. C and washed with hot dichlorobenzene until the filtrate emerges colourless, the dichlorobenzene is displaced by methanol and the product is finally washed with hot water. After drying, 5.5 parts of an orange-yellow colorant of the formula ##STR9## are obtained.

The pigment thus prepared is outstandingly suitable for the production of printing inks, having good flow, for the graphic trade, and gives very deep, pure yellow prints of good gloss and transparency.

The treatment in the organic solvent can also be carried out directly with the moist filter cake without prior drying. Thus, the moist press cake can be stirred in picoline at 100.degree.-120.degree. C, filtered off and washed with methanol and subsequently with dilute hydrochloric acid or the moist press cake is stirred into chlorobenzene, o-dichlorobenzene or nitrobenzene, freed from water by azeotropic distillation and then worked up as described above.