METHOD OF PREPARING WATER SOLUBLE CROSS-LINKED COPOLYMERS Russian patent published in 1995 - IPC

FIELD: chemistry of polymers. SUBSTANCE: method involves copolymerization of methacrylic acid and butylacrylate in the presence of cross-linking agent and initiating agent at two- or three-fold loading monomer mixture. Initiating agent is added to monomer mixture, and every load contains 1/2 or 1/3 part of total monomer quantity and initiating agent. The first load has 0.6-0.7 wt. -% cross-linking agent amd the following ones 1.2-1.4 wt.-% of monomer mass. After termination of polymerization 35-70 wt.-% of total carboxy-groups were neutralized with monoethanol- or diethanolamine followed by drying prepared copolymer. EFFECT: increased viscosity of copolymer, retained high yield of product. 2 tbl