Azo dyestuff colour deepening - by diazo coupling in presence of exocyclic ketone (autocondensate)

摘要

The depth of colour of azo dyestuffs is increased by carrying out diazo coupling in the presence of an exocyclic ketone or its oligomeric autocondensate. Technique can be used in the diazo-type copying and duplicating process. It ensures high covering power at minimal coating thickness. The exocyclic ketone pref. is cyclohexanone or its alkyl-substd. derivs., esps., with a total of is not >6C in the alkyl gps. The condensate is formed by action of acids or alkalis and/or heat on the ketone.