Prodn. of co-condensate for use as dispersant e.g. for pigment

摘要

Cocondensates (I) of ketones of formulae (II) and (III), HCHO and a sulphite salt (IV) are claimed: R1-CO-R2 (II), R3-CO-R4 (III); R1, R2 and R3 independently = (substd.) aliphatic gps. pref. (substd.) 1-4C alkyl, opt. with hetero-atoms or gps., e.g. -O-, or -NH-, in the chain; or CR1R2 = a (substd.) cycloaliphatic gp., pref. a 3-7 membered (substd.) satd. carbocycle; R4 = a (substd.) aromatic gp., pref. (substd.) phenyl.