Hoya Corporation

Mitsuo Sugimura

Kazuo Inoue

Masahisa Kosaka

Eiichi Yajima

Kunio Sasaki

Yoshiro Hirose

Takeshi Sakamoto

A polyurethane lens is produced by (a) adding to a monomer mixture comprising a polyisocyanate and a polythiol, a phosphoric acid ester represented by the general formula (I) ##STR1## (R.sub.1 and R.sub.2 which may be the same or different are each an alkyl group of 1-8 carbon atoms) and then (b) subjecting the monomer mixture containing the phosphoric acid ester, obtained in the step (a) to cast polymerization in a mold for plastic lens production. Said polyurethane lens has good releasability from mold, is free from color unevenness after tinting and cloudiness, and possesses high refractive index (N.sub.D) and high optical dispersion.

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Hamura, Japan

Mitsuo Sugimura