JPS6424740A - Light-shield glass for windshield of automobile - Google Patents

Abstract

PURPOSE:To obtain a light-shield glass for windshield of automobiles, on which the color forming density varies almost continuously, by distributing the concentration of photochromic material in an interemediate resin layer which is sandwiched between two glass plates and at least partly contains the photochromic material. CONSTITUTION:Usually an inorganic glass is used and occasionally also an organic glass can be used as glass plate. An intermediate resin layer is composed of a transparent resin as foundation and a photochromic material. As the transparent resin, the resin with high transparency can be used such as vinyl resin, acrylic resin, polyester resin, polyamide resin. As the photochromic material, the usually known material can be used for example, 6-nitrospito- benzopyran, benzothiopyran-spiropyran, etc. Above all, it is pref. to use the spiro-oxazine derivative which is superior in terms of durability in repeating the color forming and decoloring. The distribution of concentration of this material should be preferably arranged in such a manner that it is almost continuously denser toward the edge of the resin layer and thinner toward the center.