Process for the production of a photochromic object

US6171525A · kind A · utility

Assignee

• Optische Werke G. Rodenstock · DE

Inventors

• Erhard Effer · Pöcking, DE
• Manfred Melzig · Weßling, DE
• Herbert Zinner · Pentling, DE
• Herbert Schuster · Grafing, DE

Key dates

• Filing date: Jan 12, 1998
• Grant date: Jan 9, 2001
• Expiry date: Jan 12, 2018

Classification

• Technology area (CPC G): Physics
• CPC primary: G02B1/04
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

Disclosed is a process for the production of a photochromic object, composed of a polymer and containing at least one spirooxazin compound, having the following process steps: PA1 an acrylate monomer or a methacrylate monomer, respectively a mixture of a multiple thereof is utilized as the polymerizable monomer, PA1 the photochromic dyes as well as a polymerization initiator are mixed in the polymerizable monomer, PA1 the mixture yielded thereby is placed in a casting mold, polymerized and hardened. The present invention is distinguished by, PA1 in order to obtain a neutral gray, neutral brown or green photochromic tint of the polymerizable mixture, several photochromic dyes being added of which at least one is not a spirooxazin, and by the concentration PA1 of the spirooxazin compound(s) amounting to no more than 0.045 weight percent relative to the mass of the utilized monomer, and that PA1 of the polymerization initiator(s) amounting to more than 1 weight percent relative to the mass of the utilized monomer.