PULVERIZABLE ACRYLIC RESINS

摘要

Copolymer having an average molecular weight of 500 to 10,000, a glass transition temperature of 40 to 70.degree.C and an acid number of 55 to 120 mg of KOH/g of copolymer, said copolymer being the product of free radical copolymerization of a monomer mixture of I. 0 to 55 mol % of styrene, .alpha.-methylstyrene, methylmethacrylate or mixtures thereof; II. 10 to 25 mol % of acrylic acid, methacrylic acid or mixtures thereof; III. 0 to 70 mol % of at least one ester of methacrylic acid containing 2 to 18 carbon atoms in the alcohol component and IV. 20 to 50 mol % of at least one ester of acrylic acid containing 1 to 18 carbon atoms in the alcohol component, and process of producing said copolymer by continuously polymerizing said monomer mixture in a continuously fed process under steady state and perfectly agitated conditions to a conversion of 35 to 60 mol % and then polymerizing resulting polymerization reaction mixture to a conversion of at least 94 mol % under non-steady state conditions which prevent back mixing of the polymer produced in said second polymerization step with polymerization reaction mixture from said first polymerization reaction step in a tubular plug flow reactor under non-steady state conditions. The polymers are used in powder coatings.