Assistants for the preparation of pigment pastes and high-concentration, low viscosity pigment pastes

Claim 1

The process for the preparation of high concentration, low viscosity liquid pigments pastes consisting essentially of mixing inorganic pigments, a substantially, non-volatile liquid organic media, a suspension assistant, and, optionally, inorganic fillers, wherein said liquid pigment pastes have a concentration of inorganic pigment of at least 50% and said suspension assistant is present in an amount of from 0.5% to 20% by weight, based on the weight of said inorganic pigment and is a reaction product of the reaction of: (A) unsaturated acidic compounds selected from the group consisting of itaconic acid, an ethene dicarboxylic acid having the formula: ##STR10## and an ethene dicarboxylic acid anhydride having the formula: ##STR11## wherein R 1 and R 2 are members selected from the group consisting of hydrogen and methyl, and (B) an unsaturated ester having the formula: ##STR12## wherein R 3 and R 4 are members having 14 to 20 carbon atoms selected from the group consisting of alkenyl, alkadienyl, alkatrienyl and mixtures thereof, and A represents the acyl of an acid selected from the group consisting of itaconic acid, said ethene dicarboxylic acid, and an alkanedioic acid having the formula: HOOC--(CH.sub.2).sub.n --COOH wherein n is an integer from 1 to 10, which reaction product is produced by heating said component A and said component B in a weight ratio of 1:7 to 1:35 for from 1 to 25 hours at a temperature in the range of 200° C. to 250° C.