Process for making ethanol solutions of alkyl half-esters of copolymers of maleic anhydride and a C.sub.1 -C.sub.4 alkyl vinyl ether

Abstract

What is described herein is a process for making ethanol solutions of alkyl half-esters of copolymers of maleic anhydride and a C.sub.1 -C.sub.4 alkyl vinyl ether which are benzene and acetone-free. The invention is characterized by (a) precharging a reactor with excess C.sub.1 -C.sub.4 alkyl vinyl ether as both monomer reactant and solvent, and a free radical polymerization initiator, at a reaction temperature; (b) feeding the alkyl half-ester of maleic anhydride formed by reaction of substantially one mole of maleic anhydride and substantially one mole of alkanol into the precharged reactor to form the desired alkyl half-ester of the alternating copolymer of maleic anhydride and the C.sub.1 -C.sub.4 alkyl vinyl ether in excess alkyl vinyl ether as solvent; (c) cooling the reactor to room temperature; and (d) introducing ethanol solvent into the reactor and removing excess alkyl vinyl ether to form the desired half-ester copolymer in ethanol solution.

Dependencies are inferred from the claim text.