Example 15
N-butyl methacrylate (Kyoeisha Chemical Co., Ltd., Light Ester NB) 200 parts, 175 parts of monomer D, 90 parts of 4-hydroxybuthyl acrylate and 25 parts of styrene were mixed to prepare a monomer mixture solution, and 25 parts of 2,2′-azobis(2,4-dimethylvaleronitrile) (Wako Pure Chemical Industries, V-65) as an initiator was dissolved in an aromatic hydrocarbon (T-SOL 100) to prepare an initiator solution.
Aromatic hydrocarbon (T-SOL 100) 490 parts was placed in a stirrable flask, and the monomer solution and the initiator solution were added dropwise while nitrogen was enclosed. The polymerization temperature at this time was 100° C. The dropwise addition was carried out for 2 hours, and further aging was carried out at 100° C. for 4 hours to obtain a polymer solution J.