Nippon Kayaku Kabushiki Kaisha

Showa Highpolymer Co., Ltd.

Goichi Yamaguchi

Eiichiro Takiyama

Toshiaki Sugimoto

Susumu Nagao

This invention relates to a method for stabilizing unsaturated cycloacetal resin produced by reacting (I) cycloacetal compound prepared by the condensation of polyhydric alcohol more than tri-hydric and unsaturated aldehyde, with (II) unsaturated alcohol having a radical-polymerizable unsaturated bond and an alcoholic hydroxyl group in the same molecule, and optionally further with one or more compounds selected from the group consisting of polyhydric alcohol, hydroxy polyether and hydroxy polyester, in the presence of acid catalyst, characterized by adding one or more compounds selected from the group consisting of ammonia, primary amine, secondary amine, tertiary amine, quaternary ammonium salt, hydrazine and its derivatives in an amount of 0.01 to 5 parts by weight per 100 parts by weight of the produced unsaturated cycloacetal resin during the reaction of producing the unsaturated cycloacetal resin and/or after the reaction and maintaining pH of the unsaturated cycloacetal resin (pH of a 50% methyl alcohol solution of the resin) at more than 4.

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Urawa, Japan

Goichi Yamaguchi