Photochromic epoxy resin coating composition and articles having such a coating
AssigneePPG Industries Ohio, Inc.
InventorsRobert W. Walters, Cletus N. Welch, John W. Burgman, Debra L. Singer, Shanti Swarup
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Abstract
Described are photochromic epoxy resin coatings that meet commercially acceptable “cosmetic” standards for optical coatings. Also described are articles having such coatings. The coatings exhibit a Fischer microhardness of from 50 to 150 Newtons per mm2 and desirable photochromic properties, i.e., the formation of darker activated colors and faster rates of photochromic activation and fade when irradiated with ultraviolet light.
Claims27
An article comprising, in combination, a substrate and a photochromic polyacid cured epoxy resin coating on at least one surface of said substrate, said photochromic epoxy resin coating having a Fischer microhardness of from 50 to 150 Newtons per mm2, a 72° F. ΔOD of at least 0.15 after 30 seconds and at least 0.50 after 15 minutes, and a bleach rate of less than 200 seconds.
Dependencies are inferred from the claim text.