Abstract: Mixed esters comprising the reaction product ofa) an aliphatic, cycloaliphatic and/or aromatic C.sub.2 -C.sub.22 -dicarboxylic acid containing up to 2 hydroxyl groups, or a mixture thereof;b) an aliphatic polyol containing from 3 to 6 hydroxyl groups or a mixture thereof; andc) an aliphatic C.sub.2 -C.sub.32 -monocarboxylic acid containing up to 2 hydroxyl groups, or a mixture thereof;wherein the molar ratio of components a) and b) is approximately n-1:n, wherein n is an integer of from 6 to 15, and component c) is selected so that at least one free hydroxyl group is present per molecule of the mixed ester, are useful as lubricants for the molding of thermoplastic plastics, especially polyvinyl chloride homopolymers or copolymers.