Patent GB-1236421-A (GB)
Title: Photochromic recording member
IPC: G03C5/305
Filed: 1968-02-15
Abstract: 1,236,421. Photochromic materials and uses thereof. CANON K.K. 15 Feb., 1968 [20 Feb., 1967; 31 May, 1967; 19 June, 1967; 2 Aug., 1967; 16 Aug., 1967], No. 7525/68. Heading C4S. [Also in Division G2] A photochromic recordingmember comprises a base and photochromic coating comprising a wholly organic monomeric photochromic material, defined as including salts of organic bases involving inorganic ions selected from photoion dissociating, photo-radical dissociating, photo - hydrogen transmitting, photo - steric structure changing, and photo-oxidizing or - reducing materials, and a stabilizer comprising one or more of (a) an organic monomeric compound which is an electron donor selected from polycyclic aromatic compounds, aliphatic amines and aromatic amines, or a proton donor selected from phenols, alcohols and carboxylic acids, or an electron acceptor selected from quinones and nitroaromatic compounds or a proton acceptor selected from heterocyclic nitrogen containing aromatic compounds and azoaromatic compounds, the layer having been formed by coating the base with a solution of the photochromic material in a solvent of the compound (a); (b) a solid (or gel) material selected from acids (including Lewis acids), bases (including Lewis bases), and crystalline ionic compounds; (c) a solid (or gel) material which has been treated with an acid or base to cause a surface portion in contact with the photochromic material to behave as a Lewis acid or base. The solid (or gel) material (b) or (c) may have been coated on the surface and subsequently a solution or dispersion of the photochromic material added to form a heterogeneous rather than homogeneous system, the latter normally employing liquid matrices although film forming or adhesive substances may be matrices in both cases. A large number of photochromic materials and stabilizers are disclosed, the former of types such as carbinols, cyanides, sulphites, spiropyrans, anils, aromatic nitro compounds, bianthrones for instance. Specific example combinations include (a) malachite green cyanide, tetra cyanoquinodimethane, ethyl cellulose and alcohol, on glass, (b) salicylidene anil, acridine and resin; (c) kaolin, ethyl alcohol or acidic terra alba with ethyl alcohol or ethyl cellulose, dioxane, kaolin on art paper and bentonite, ethyl alcohol on Al with 6<SP>1</SP> - nitro - 1,3,3 - trimethylindolinobenzopyrylspiran, (d) kaolin, ethyl alcohol and 6<SP>1</SP>-nitro- 1,3,3-trimethylindolinobenzopyrylspiran on art paper, Al or glass, (e) 6<SP>1</SP>-nitro-1,3,3-trimethyl indolinobenzopyrylspiran, p-nitrophenol, polystyrene and xylene on glass. Stabilization for 60 hours, colorization and bleaching by U.V. and visible light is disclosed. Reference is made to a projection system as in Specification 1,236,424. Applications exemplified include, photography, electrophotography, calculation, translation, communication, documentation, information treating systems for recording, accumulating, modifying-and erasing information layout, e.g. phototyping materials, master sheets for printing, materials for telecommunication machines and computers.