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AssigneeMitsui Toatsu Chemicals, Inc.
InventorsYoshinobu Kanemura, Katsuyoshi Sasagawa, Seiichi Kobayashi
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A mercapto compound represented by the following formula (1): ##STR1## is obtained by reacting, in the presence of a mineral acid, thiourea with a compound represented by the following formula (2): ##STR2## wherein X means a hydroxyl group or a chlorine or bromine atom, and then adding a base to alkalinize the reaction mixture so that the reaction product is hydrolyzed. The mercapto compound represented by the formula (1) can be reacted with at least one cyanate compound selected from the group consisting of polyisocyanate compounds, polyisothiocyanate compounds and isocyanate-group-containing isothiocyanate compounds to form a sulfur- containing urethane resin. A lens made of the resin is colorless and transparent, has high refractive index and low dispersion characteristics, and is excellent especially in heat resistance.
A sulfur-containing urethane resin obtained by reacting a mercapto compound represented by the following formula (1):
A process for the production of a sulfur-containing urethane resin, which comprises heating and curing a mixture composed of a mercapto compound represented by the following formula (1):
A sulfur-containing urethane resin lens obtained by cast-polymerizing a mercapto compound represented by the following formula (1):
A process for the fabrication of a sulfur-containing urethane resin lens, which comprises cast-polymerizing a mercapto compound represented by the following formula (1):
Dependencies are inferred from the claim text.