Patent ID: 6171525
Filing Date: 2001-01-09
Classification: B29C,C08F,C08K,C09K,G02B

Abstract:
A process for the production of a photochromic object, composed of a polymer and containing at least one spirooxazin compound, comprising:mixing a polymerizable monomer selected from the group consisting of an acrylate monomers a methacrylate monomer, and a mixture of a multiple thereof, withphotochromic dyes as well as a polymerization initiator to obtain a photopolymerizable mixture, andplacing the photopolymerizable mixture yielded thereby in a casting mold, to polymerize and harden said mixture,wherein,in order to obtain a neutral gray, neutral brown or green photochromic tint of said polymerizable mixture, several photochromic dyes are added of which at least one is not a spirooxazin, and the concentrationof the spirooxazin compound(s) amounts to no more than 0.045 weight percent relative to the mass of the utilized monomer, and an amountof said polymerization initiator(s) is at least 1.5 weight percent relative to the mass of the utilized monomer.