The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 04, 1994
Filed:
Dec. 20, 1993
Yoshinobu Kanemura, Yokohama, JP;
Katsuyoshi Sasagawa, Yokohama, JP;
Seiichi Kobayashi, Kamakura, JP;
Mitsui Toatsu Chemicals, Incorporated, Tokyo, JP;
Abstract
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.