Patent ID: 6166129
Filing Date: 2000-12-26
Classification: C08G,C08K,C09B,G03C

Abstract:
A thermoplastic photochromic polyurethane characterized by a .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 about 2 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 having a functionality of about 2 and a molecular weight of from 62 to 499;b) an aliphatic polyisocyanate having a functionality of about 2; andc) a photochromic compound selected from a 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).