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:
Jul. 14, 1992
Filed:
Mar. 07, 1990
Scott Fischer, Clinton, OH (US);
Cletus N Welch, Murrysville, PA (US);
PPG Industries, Inc., Pittsburgh, PA (US);
Abstract
A process for incorporating by thermal diffusion a photochromic substance into a synthetic organic host material is described. In the process, a surface of the host material containing a coating of a resin composition of from about 5 to about 50 parts of hydroxy (C.sub.2 -C.sub.3) alkyl cellulose, e.g., hydroxy propyl cellulose, and from about 95 to about 50 parts of poly(vinylpyrrolidone), which resin composition contains a photochromic substance, is heated to diffuse at least a portion of the photochromic substance into the surface of the host material. Subsequently, the coating is removed by washing with warm soapy water. In a particular embodiment, the host material is a polymer prepared from diethylene glycol bis(allyl carbonate).