Patent ID: 6844415

Claim:
Polymerizable composition for making thio containing resins comprising, A) at least one polyisocyanate or polyisothiocyanate monomer and at least one polythiol or at least one episulfide compound and optionally one or more compounds having two or more functional groups capable of reacting with episulfide groups; and B) a polymerization catalyst, wherein the polymerization catalyst comprises an effective amount of at least one salt of formula: M m P +Y n − wherein M P+ is a cation selected from the group consisting of alkaline metals, alkaline earth metals, transitions metals and ammonium groups of formula NR + 4 in which R is an alkyl radical, Y − is an anion such as the corresponding acid YH has a pKa fulfilling the condition 0.5≦pKa≦14 with the proviso that when the polymerizable compositions comprise an episulfide compound and M P+ is an ammonium group, the polymerizable composition also comprises an electro-donor compound, p is the valency of the cation, and n=m×p.