High-refractivity plastic lens resin formed from a polyisocyanate and a polythiol
AssigneeMitsui Toatsu Chemicals, Inc.
InventorsYoshinobu Kanemura, Katsuyoshi Sasagawa, Masao Imai, Teruyuki Nagata, Nobuyuki Kajimoto
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Abstract
Disclosed herein is a colorless transparent plastic lens having high refractivity and low dispersion. The lens is light, has heat resistance sufficient for post processing, and is excellent in grinding machinability and impact resistance. It is made of a sulfur-containing urethane resin, which is a polymer of a specific polythiol and a particular polyisocyanate of at least bifunctionality.
Claims14
A high-refractivity plastic lens resin obtained by polymerizing, with at least one polyisocyanate of at least bifunctionality, at least one polythiol represented by the general formula (I):
- ##STR2## wherein K is a substituent --CH.sub.2 --(CHR).sub.m (O).sub.n (CO).sub.p (CH.sub.2).sub.q SH in which R represents a hydrogen atom or methyl group, m is an integer of 0-3, n is an integer of 0-1, p is an integer of 0-1 and q is an integer of 1-3.
A lens comprising a copolymer obtained by polymerizing under heat at least one polythiol, which is represented by the following general formula (I):
- ##STR3## wherein K is a substituent --CH.sub.2 (CHR).sub.m (O).sub.n (CO).sub.p (CH.sub.2).sub.q SH in which R represents a hydrogen atom or methyl group, m is an integer of 0-3, n is an integer of 0-1, p is an integer of 0-1 and q is an integer of 1-3, with at least one polyisocyanate of at least bifunctionality.
Dependencies are inferred from the claim text.