Process for the production of polyurethane lens
AssigneeHoya Corporation
InventorsMasahisa Kosaka, Yukio Kageyama
Life of this patent
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Abstract
The present invention relates to a process for the production of a polyurethane lens, which comprises the step (a) of providing a polyisocyanate compound and two or more polythiol compounds which have different reaction rates with the polyisocyanate compound and adding an alkyltin halide compound to the above polyisocyanate compound, and, after the step (a), the step (b) of mixing the polyisocyanate compound and the two or more polythiol compounds together with the alkyltin halide compound of the general formula (I) to allow them to react, and obtaining a polyurethane lens.
Claims13
A process for mass-producing a polyurethane ophthalmic lens comprising the steps of:
- (A) adding an alkyltin halide compound of the formula (I),
- (R1)c—Sn—X4−c (I)
- wherein R1 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.
Dependencies are inferred from the claim text.