Light sensitive metal lake - by coupling diazonium salt with coupling component in presence of polyvalent metal salt

摘要

Polyvalent metal lake of an azo dye for use in electrophoretic image forming is prepd. by coupling a diazonium salt of an org. amine with a coupling component in the presence of a salt of a polyvalent metal. The org amine is substd. by acidic or salt-forming gps., opt. together with alkyl, nitro, cyano, alkoxy, thio, ester and/or aldehyde gps. The coupling component is substd. by halogen, nitro, alkyl, cyano, alkoxy, thio, carboxyl, sulphonic acid, ester and/or ester gps. The metal salt consists of a chloride of aluminium, zinc, calcium, ferric iron, magnesium or stannous tin, arsenic triiodide or strontium or chromium bromide. Coupling is effected at an alkaline pH. High colour purity, high light sensitivity, excellent relation between the max. spectral response and the max. light sensitivity are achieved.