GB524854A - Improvements in and relating to fluorescent substances - Google Patents

Abstract

524,854. Luminescent materials. BRITISH THOMSON-HOUSTON CO., Ltd., and ANDERSON, J. T. Feb. 14, 1939, Nos 4847 and 4997. [Class 39 (i)] Fluorescent material consists of a luminescent organic compound dispersed in silica in wholly or partially dehydrated form ; the silica and organic compound may be in a common solution from which the silica is precipitated the phosphor being adsorbed or precipitated at the same time. Ethyl silicate or an alcoholic solution of silica known as Silicon Ester medium may be used with rhodamine B or GB, auramine anthracene, acriflavine or aesculin. They may be precipitated together from a common solution, dried in an oven below 150‹C. and then crushed ; or a layer obtained from a dyecolloidal SiO 2 solution may be used as a layer or broken up into fragments. The fluorescent material may be deposited on other particles as described in Specification 524,802 or silica may be deposited thereon as described in Specification 521,099. As a paint the dye is applied with a colloidal solution of silica which in weathering or drying produces a film of silica. This material can be applied to plaster, bricks, concrete &c., the surfaces of which can be roughened before applying the paint ; it may be used to mark roads, pavements, concrete lamp standards &c. Finely ground silica or sillimanite may be mixed with the paint.