Mitsubishi Gas Chemical Company, Inc.

Naotsugu Shimoda

Motoharu Takeuchi

Teruo Kamura

Eiji Koshiishi

Yoshihiko Nishimori

By using a method for producing a composition for an optical material using (a) sulfur, (b) a compound having two intramolecular episulfide groups, (c) a compound having one or more (preferably two) SH groups, and (d) an amine compound having a specific structure, in which compound (a) and compound (c) are pre-polymerized in the presence of compound (b) using compound (d) as the pre-polymerization catalyst, the present invention provides a polymerizable composition for an optical material in which the viscosity elevation speed during pre-polymerization is slow and the reaction temperature is approximately room temperature, and that has a low viscosity and shows little increase in viscosity. By means of another embodiment of the present invention, it is possible to produce an optical material that has excellent mold release characteristics but has substantially no striae by polymerizing (a) sulfur, (b) a compound having two intramolecular episulfide groups, and (c) a compound having one or more SH groups in the presence of (d) a hindered amine catalyst having a specific structure.

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Tokyo, Japan

Naotsugu Shimoda