Patent ID: 6274694
Filing Date: 2001-08-14
Classification: C08G,G02B

Abstract:
A process for mass-producing a polyurethane ophthalmic lens comprising the steps of:(A) adding an alkyltin halide compound of the formula (I),(R.sub.1).sub.c --Sn--X.sub.4-c (I)wherein R.sub.1 is methyl, ethyl, propyl or butyl, X is a fluorine atom, a chlorine atom or a bromine atom and c is an integer of 1 to 3,to a polyisocyanate compound in an amount necessary to mass-produce the ophthalmic lens to form a first mixture;(B) subsequent of step (A), adding two or more polythiol compounds in an amount necessary to mass-produce the ophthalmic lens to the mixture of step (A) to form a second uniform mixture, said polythiol compounds having different reaction rates with the polyisocyanate compound;(C) subsequent to step (B), degassing the second mixture;(D) subsequent to step (C), pouring the resulting mixture of step (C) into a number of ophthalmic lens molds necessary to mass-produce the ophthalmic lens, and(E) heating the filled lens molds of step (D) in the same single polymerization furnace and allowing the mixture to react to obtain the ophthalmic lens.