A rheology modifier for solvent-based coatings which is a polyacrylic acid or a poly(C1-4)-alkyl acrylic acid wherein at least 30 % of the -COOH groups are converted to ester and/or amide groups. Preferred compounds are esters of polyacrylic acid where about 50 % of the -COOH groups are esterified with a C4-12-alcohol.
