| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for obtaining a copolymer having a specific composition and a specific physical properties economically in a short time. SOLUTION: The copolymer of this invention has >=50,000 weight average molecular weight, <=7 ratio of (weight average molecular weight/number average molecular weight), <=1,000 ppm residual polymerizable component of acidic or basic olefins, <=5,000 ppm total residual component except olefins and <=100 ppm residual polymerization initiator, and is obtained in a short time by the following method: (1) employing a polymerization initiator not including an acid group and not forming an acid group as a decomposition product; (2) charging a monomer mixture in a solvent so as to obtain a copolymer having the composition consisting of (A) 1-60 wt.% monomer of formula I (R1 is a 1-4C alkyl), (B) 0.1-40 wt.% monomer of formula II (R2 is a 1-8C alkyl), (C) 0.1-40 wt.% acrylic acid or the like and (D) 0-60 wt.% polymerizable compound; (3) throwing a half of the monomers so as to reach the boiling point within 30 min; (4) dripping the remaining monomers within 120 min on reaching the boiling point and adjusting the viscosity through the dilution with the solvent as the viscosity increases; and (5) setting the time required for polymerization to become <=10 h.
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