GB821968A - Improvements in or relating to surface-coating additives - Google Patents

Abstract

A composition for improving the fire-retardant properties of surface-coating compositions comprises paraformaldehyde, urea, dicyandiamide and one or more ammonium phosphates. It may be added to paints, lacquers and the like or to any constituent thereof and may be hardened before incorporation by heating. It may be used in conjunction with phenolformaldehyde and amine-formaldehyde resins, e.g. urea, melamine and dicyandiamide resins, and chlorinated rubber. Inflammability can be reduced by the addition of e.g. chlorinated paraffins, chlorinated diphenyls and trichlorethyl phosphate and the use of volatile chlorinated hydrocarbons as solvent. In examples: (1) a mixture of urea, dicyandiamide, paraformaldehyde, monoammonium phosphate and chalk is added to a chlorinated rubber lacquer containing chlorodiphenyl; (2) a mixture of urea, dicyandiamide, paraformaldehyde, monoammonium phosphate and dextrin is added to a lacquer containing a phenolic resin and polyvinylbutyral, and (3) a mixture of urea, dicyandiamide, paraformaldehyde, monoammonium phosphate, methyl cellulose and chalk is added to a phenolic resin lacquer containing chlorinated paraffin wax and a hardener. The compositions may be used by themselves or be added to a lacquer binding agent and applied to form an intermediate layer between two layers of paint or other coatings on a surface; or successive layers containing varying amounts of additive may be applied.ALSO:A composition for improving the fire-retardant properties of surface-coating compositions comprises 1 part (by weight) paraformaldehyde, 0.5-0.8 parts urea, 1.2-1.3 parts dicyandiamide and 1.0-1.7 parts of one or more ammonium phosphates. It may be added to paints, lacquers and the like or to any constituent thereof and may be hardened before incorporation by heating. It may be used in conjunction with phenol-formaldehyde and amine-formaldehyde resins, e.g. urea, melamine and dicyandiamide resins, and chlorinated rubber. Inflammability can be reduced by the addition of e.g. chlorinated paraffins, chlorinated diphenyls and trichlorethyl phosphate and the use of volatile chlorinated hydrocarbons as solvent. In examples: (1) a mixture of urea, dicyandiamide, paraformaldehyde, monoammonium phosphate and chalk is added to a chlorinated rubber lacquer containing chlorodiphenyl xylene and butanol; (2) a mixture of urea, dicyandiamide, paraformaldehyde, monoammonium orthophosphate and dextrin is added to a lacquer containing ethyl alcohol, butyl acetate, butyl alcohol and ethylene glycol, a phenolic resin and polyvinylbutyral; and (3) a mixture of urea, dicyandiamide, paraformaldehyde, monoammonium orthophosphate, methyl cellulose, butyl acetate and chalk is added to a phenolic resin lacquer containing chlorinated paraffin wax, ethyl alcohol, butyl acetate, ethylene glycol and a hardener (phosphoric acid and butyl alcohol). The compositions may be used by themselves or be added to a lacquer binding agent and applied to form an intermediate layer between two layers of paint or other coatings on a surface; or successive layers containing varying amounts of additive may be applied.