GB503760A - Improvements in and relating to fluorescing compositions - Google Patents

Abstract

503,760. Fluorescing compositions. BRITISH THOMSON-HOUSTON CO., Ltd. Oct. 6, 1937, No. 27087. Convention date, Oct. 8, 1936. [Class 39 (i)] [Also in Group IV)] A fluorescing composition which is suitable for making a light transforming surface, such as a screen or reflector comprises an alkali metal salt of Rhodamine B and a binder. An alcoholic solution of the potassium salt of Rhodamine B, diluted with a solution of cellulose acetate in a solvent such as acetone may be used to coat a screen or reflector, or solutions of Rhodamine B and of potassium hydroxide in a solvent may be mixed with a solution of cellulose acetate in acetone to obtain a suitable coating composition. A supporting member may also be coated first with a solution containing an alkali metal salt of Rhodamine B and a binder, and then with a solution of a binder in a solvent, the coatings being dried after each application. A product obtained by reacting an aldehyde with a hydrolysed polymerized vinyl ester may be used as a binder. To improve the brushing properties of the solutions, high boiling solvents may be added, such as ethylacetate, ethyleneglycolmonoethylether, or the acetate of the latter ether. Organic and inorganic binders may be used and supports for the composition may be made of metal, e.g. aluminium, nickel, chromium or steel, glass, porcelain, enamelled material, paper, cardboard, silk, rayon, linen, cotton or other textile. The use of the composition in metal vapour lamps, e.g. mercury vapour lamps is mentioned. The composition may be applied to a temporary support, dried and after removal used independently of any support as a light transforming or fluorescent screen, Lithium, sodium, rubidium and caesium salts of Rhodium B are specified. Specifications 16271 /11, [Class 95], and 477,192, [Group XX], are referred to.