PURPOSE: To obtain a flame retardant composition highly soluble to water without deterioration by formalin, useful for cellulose-based materials seldom developing discoloration or paper strength drop-off after heated, essentially comprising a reaction product of an inorganic acid ammonium salt and dicyandiamide.
CONSTITUTION: This flame retardant composition essentially comprises a compound of the formula (A is the active hydrogen residue of a reaction product of an inorganic acid ammonium salt and dicyandiamide; R1 and R2 are each H or a 1-5C hydrocarbon; M1 and M2 are each a mono-to trivalent metal, ammonium or H; (m) is an integer of 0 or 1; (n) is an integer of 1-5). The compound of the formula is pref. a reaction product obtained by reaction of a reaction product of an inorganic acid ammonium salt (pref. ammonium sulfamate) and dicyandiamide with lower alkyl (pref. 1-4C alkyl)diester(s) of at least one kind of α, β-unsaturated dicarboxylic acid selected from maleic acid, fumaric acid and itaconic acid followed by conducting a hydrolysis.