GB721827A - Improvements in or relating to fluorescent coating compositions - Google Patents

Abstract

A fluorescent coating composition comprises a volatile organic solvent solution of at least one synthetic resinous condensation product in physical or chemical combination with at least one fluorescent dye, and at least one finely-divided solid light diffusing medium (extender), preferably having a particle size not greater than 2 microns and a refractive index not differing from that of the resin by more than 15 per cent, the resin constituting at least 35 per cent by weight of the composition, and the dye being in a proportion not exceeding that at which optimum brightness is achieved. The dye-resin combination may be formed, e.g. by adsorption, solvation or by ester formation between a carboxylate group in the dye and a hydroxyl group of the resin. The compositions may be made by dissolving the resin(s) in a solvent or solvent mixture, adding the dye(s) thereto and heating; the extender(s) is then stirred in and the mixture further heated. Ingredients specified are:-Fluorescent dyes-4 - amino - 1 : 8 - naphthalic acid - 41 - phenylanilide sodium sulphonate, 4-amino-1 : 8-naphthalic acid-41-methylanilide, 4-amino-1 : 8-naphthalic acid - cyclohexylamide, 3 : 6 - diamino - acridine methochloride hydrochloride, dimethyl dehydrothiotoluidine - methochloride, 3 : 6 - bisethylamino - 9 - (21 - carbethoxy - phenyl) - xanthenyl - chloride, 3 : 6 - bis - diethylamino - 9 - (21 - carboxyphenyl) - xanthenyl chloride, 3 : 6 - bis - diethylamino - 9 - (21 - sulphophenyl)-xanthenyl sodium sulphonate. Non-fluorescent dyes and pigments may also be added: resins-glyceryl phthalate (modified and unmodified), alkylated (e.g. butylated) urea-formaldehyde, alkylated (e.g. butylated) melamine-formaldehyde, cyclohexanone - aldehyde, epoxide, sulphonamide-aldehyde and polyurethane (e.g. toluene diisocyanate and butylglyceryl phthalate) resins. Other resinous materials which may be added are nitro-, acetyl-, ethyl-, benzyl-, acetyl-butyryl- and acetyl-propionyl-celluloses; polymethacrylate, polyvinyl - acetate and -chloride, polyvinylidene chloride and their copolymers; extenders-silica, magnesia, alumina, powdered urea- and melamine-formaldehyde resins, mica, china clay, rice starch and acetylated starch; solvents-diacetone alcohol, ethyl acetate, butyl acetate, ethyl lactate, acetone, methyl isobutyl ketone, white spirit and butanol-xylene mixture. Cobalt and lead driers or acid catalysts such as phosphoric and p-toluene sulphonic acids may be added to the compositions. Examples are given. Specification 456,480 is referred to.