HIGH-TEMPERATURE VISCOSITY-STABLE THICKENER

摘要

PROBLEM TO BE SOLVED: To provide a hydrophobic substance-containing alkali-soluble or alkali- swelling copolymer thickener. SOLUTION: The titled thickener contains an emulsion polymerization product of (A) an ethylenically unsaturated copolymerizable surfactant monomer M(EO)x(PO)y(BO)z OR1 (wherein M is a residue chosen from the group consisting of an ethylenically unsaturated carboxylic acid, an ethylenically unsaturated dicarboxylic acid and a copolymerizable isocyanate; EO is an ethylene oxide unit; PO is a propylene oxide unit; BO is a butylene oxide unit; provided that x+y+z is from 20 to 45, x is from 10 to 45, y is from 0 to 35 and z is from 0 to 35; and R1 is an 1-30C alkyl group or the like) having a clouding point of from 65 to 95 deg.C, (B) an alpha, beta-ethylenically unsaturated monocarboxylic acid monomer and (C) a non-ionicα,β-ethylenically unsaturated monomer. This copolymer yields an aqueous composition having a constant viscosity or increased viscosity at a temperature near 120 deg.C.