Patent ID: 8586694

Claim:
A polymerizable composition for a polythiourethane-based optical material comprising a monomer mixture including polyiso(thio)cyanates and active hydrogen compounds with a molar ratio of the functional groups of the iso(thio)cyanato groups contained in said polyiso(thio)cyanates to the mercapto groups contained in said active hydrogen compounds in a range of 0.5 to 3.0, and a polymerization catalyst for a polythiourethane-based optical material comprising a sulfonate represented by the formula (1), in a content of 0.005 parts by weight to 2 parts by weight, based on 100 parts by weight of said monomer mixture: wherein R 1 , R 2 , R 3 and R 4 each independently represent an alkyl group having 1 to 18 carbon atoms, and R 1 , R 2 , R 3 and R 4 may be bonded to each other to form a ring, and wherein R 5 represents a methyl group or tolyl group, and X represents a nitrogen atom, wherein the polymerization catalyst contained in the polymerization composition consists of the sulfonate represented by the formula (1), wherein said polyiso(thio)cyanates are one or more selected from the group consisting of m-xylylene diisocyanate, 2,5-bis(isocyanatomethyl)-bicyclo[2.2.1]heptane, 2,6-bis(isocyanatomethyl)-bicyclo[2.2.1]heptane, 1,3-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, and hexamethylene diisocyanate, and said active hydrogen compounds are one or more selected from the group consisting of 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, pentaerythritol tetrakis(3-mercaptopropionate), 1,1,3,3-tetrakis(mercaptomethylthio)propane, 1,1,2,2-tetrakis(mercaptomethylthio)ethane, 4,6-bis(mercaptomethylthio)-1,3-dithiane, and 2-(2,2-bis(mercaptomethylthio)ethyl)-1,3-dithiethane.