Interpenetrating polymer networks for contact lens production

A homogenous interpenetrating polymer network exhibiting a single glass transition temperature formed by polymerization of a reactive mixture of polymerizable components, said reactive mixture comprising

• (a) an amine mixture consisting of polyamines A and B, said amine mixture being present in about 20-60% by weight in said reactive mixture wherein A is ##STR26## and B is H.sub.2 N--R--(O--R).sub.f1 --NH.sub.2
• f.sub.1 is an integer from 1-75;
• R is an alkylene containing 3 carbon atoms;
• f is an integer between 1 and 150 inclusive;
• R.sub.10, R.sub.11, R.sub.12, R.sub.13 and R.sub.14 are independently hydrogen or lower alkyl;
• Z.sub.1 and Z.sub.2 are independently a chemical bond or lower alkylene with A and B present in relative weight percentages ranging from about 60 to about 100% A;
• and wherein A is different from B;
• (b) an organic di- or poly-isocyanate present in sufficient quantity in said reactive mixture to react with the amine mixture of (a), forming therefrom a polyurea network;
• (c) an acrylic ester of the formula:
• ##STR27## wherein R.sub.3 is hydrogen or lower alkyl;
• m is an integer from 0 to 150;
• Z.sub.3 and Z.sub.5 are independently lower alkylene;
• Z.sub.4 and Z.sub.6 are independently a chemical bond or lower alkylene;
• R.sub.4 is hydrogen, lower alkyl or ##STR28## R.sub.5 is hydrogen or lower alkyl;
• R.sub.6 and R.sub.8 are independently lower alkyl;
• p is an integer of 1 to 3;
• and
• R.sub.7 is lower alkylene or chemical bond or --CH.sub.2 (OCH.sub.2 CH.sub.2).sub.q ;
• q is an integer from 0 to 200 inclusive;
• said acrylic ester being present in about 10-50% by weight in the reactive mixtures;
• (d) a free radical initiator being present in sufficient quantity in the reactive mixture to polymerize the acrylic ester of (c), forming a polyacrylic network;
• and
• (e) a triamine being present in sufficient amount to crosslink interpenetrating polymer network;
• wherein the ratio by weight of polyurea to polyacrylic ranges from about 50:50 to about 90:10, and wherein the weights of the components in the reactive mixtures sum up to 100%.