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AssigneeNori Y. C. Chu
InventorsDonald R. Uhlmann, Elias Snitzer, Richard J. Hovey, Nori Y.C. Chu, Joseph T. Fournier, Jr.
Estimating the term…
Organic photochromic materials comprise a photochromic pigment stabilized with a protective inorganic coating which serves to protect the pigments from deactivation by exposure to moisture, oxygen, various plastic host materials, reactive chemicals or even normal atmospheric conditions. Useful organic photochromic pigments include the anils, hydrazones, semicarbozones, osazones, sydnones, fulgides and others. Inorganic coatings comprising such materials as zinc oxide, titanium dioxide, aluminum oxide, antimony oxide and silicon dioxide are useful in the preparation of photochromic plastic films, sheets, ophthalmic lenses such as lenses for sunglasses and in camera lenses and filters.
A stabilized photochromic particle for incorporation into a plastic host to impart photochromic properties thereto, said particle comprising an organic photochromic pigment crystal having a diameter in the range of 30 A to 1 micron, said photochromic crystal having a protective coating on substantially the entire surface thereof effective to render the photochromic, crystal impervious to the effects of oxygen, moisture, monomers, catalysts, and other chemicals used in the formation of the plastic host which are deleterious to said crystal.
A material which exhibits photochromic properties comprising a plastic host having a plurality of photochromic particles incorporated therein, each of said photochromic particles comprising:
A process for producing a stabilized photochromic particle suitable for incorporation into a plastic host for imparting photochromic properties thereto, said process comprising:
Dependencies are inferred from the claim text.