Copolymers and hydrogels: process and articles made thereof

Claim 1

A process for making a hydrogel contact lens, comprising the steps of: (A) forming a button from a polymer material, said polymer material being a free radical bulk polymerization product of: (a) a first monomer of the formula: ##STR32## wherein: R 1 is hydrogen or methyl; m is an integer from 1 to 4; n is an integer from 0 to 1; and X and Y are protecting groups and are independently selected from the group consisting of: (1) --C(O)OR 2 wherein R 2 is an alkyl group containing from 1 to 8 carbon atoms; (2) hexahydropyranyl; and (3) where X and Y together form one protecting group, selected from the group consisting of: ##STR33## wherein R 3 is a lower alkyl group containing 1 to 6 carbon atoms, cycloalkyl group containing 3 to 6 carbon atoms; and aryl selected from the group consisting of phenyl, tolyl and naphthyl; ##STR34## wherein R 4 and R 5 are independently hydrogen and lower alkyl groups containing from 1 to 6 carbon atoms and together may form a cyclic ring containing from 2 to 6 carbon atoms; ##STR35## wherein R 6 is a lower alkyl group containing from 1 to 6 carbon atoms; and ##STR36## (b) a second, substantially water insoluble monomer of the formula: ##STR37## wherein: R 7 is hydrogen or methyl; and R 8 is lower alkyl having 1 to 6 carbon atoms or cycloalkyl having from 3 to 6 carbon atoms; the molar ratio of said first monomer to said second monomer being between about 1:30 and 20:1; and, optionally, (c) a third, substantially water insoluble monomer of the formula: ##STR38## wherein: R 9 is hydrogen or methyl; and p is an integer from 1 to 6; or of the formula: ##STR39## wherein: R 10 and R 11 are independently hydrogen or methyl, and q is an integer from 0 to 5; the concentration of said third monomer, when present, being between about 0 and 30 percent by weight of the first monomer; (B) machining, shaping and polishing said button into the shape of a contact lens, using water compatible oils, abrasives and polishes; and (C) removing said protecting group(s) from said polymer button, as formed into the shape of a contact lens, by chemical means and replacing said protecting group(s) with hydroxyl groups.