Method for preparing photochromic plastic article
AssigneePPG Industries, Inc.
InventorsScott Fischer, Cletus N. Welch
Life of this patent
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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).
Claims16
In the process of thermally transferring a photochromic substance to a synthetic organic host material by (a) applying a coating containing the photochromic substance to the surface of the organic host material, and (b) heating the resultant coated surface, thereby to diffuse at least a portion of the photochromic substance from the coating into the host material, wherein the improvement comprises said coating being a water-strippable resin composition of from about 5 to about 50 parts of hydroxy (C.sub.2 -C.sub.3) alkyl cellulose and from about 95 to about 50 parts of poly(vinyl pyrrolidone).
Dependencies are inferred from the claim text.