Patent ID: 6107395
Filing Date: 2000-08-22
Classification: C08G,C08K,C09B,G03C

Abstract:
A photochromic polyurethane characterized by a .sub..DELTA. A at 2 minutes of greater than 50% and a T.sub.50 of less than 2 minutes consisting essentially of:a) an isocyanate reactive mixture consisting essentially of:i) from about 40 to about 85% by weight of one or more polyols having a nominal functionality of from 2 to 4 and a molecular weight of from 500 to 6000 g/mol;ii) from about 15 to about 60% by weight of one or more diols or triols or mixtures thereof having a functionality of from 2 to 3 and molecular weights of from 62 to 499;b) an aliphatic polyisocyanate having a functionality ranging from about 2 to about 3; andc) a photochromic compound selected from the group consisting of spirooxazines, fulgides, fulgimides, and naphthopyrans,wherein the photochromic compound c) is present in an amount of from 0.01 to 5 parts per hundred parts by weight of the isocyanate reactive mixture a).