The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 23, 1998
Filed:
Apr. 19, 1996
Michael S Misura, Clinton, OH (US);
PPG Industries, Inc., Pittsburg, PA (US);
Abstract
Describes a composition of a carrier, e.g., organic solvent or polymeric host material, photochromic naphthopyran material, and a stabilizer system comprising (a) polyphenolic antioxidant material, (b) ultraviolet light absorber and (c) hindered amine light stabilizer for said photochromic naphthopyran material. The stabilizer system is selected and used in amounts sufficient to provide at least a 30% reduction in % photopic fatigue of the naphthopyran material. The weight ratio of photochromic naphthopyran to the stabilizer system is from 2.5:1 to 1.5:1. The stabilizer system can comprise 5 to 50 weight percent of the antioxidant material, 5 to 50 weight percent of the ultraviolet light absorbent, and 10 to 90 weight percent of the hindered amine light stabilizer.