HARDLY SOLUBLE MELAMINE POLYPHOSPHATE

摘要

PROBLEM TO BE SOLVED: To provide a more hardly soluble melamine polyphosphate than conventional ones which does not suffer from a problem of increase in conductivity on moisture absorption. SOLUTION: The more hardly soluble melamine polyphosphate than conventional ones is obtained by adding a calcium compound and/or an alkali to a melamine polyphosphate dispersed in water thereby raising the pH of the liquid up to at least 8, and subsequently lowering the pH of the liquid by at least 1 by adding a phosphoric acid compound and/or an acid. Addition of calcium phosphate before addition of the phosphoric compound and/or the acid increases the rate of formation of the hardly soluble melamine polyphosphate. Washing with water and/or an organic solvent after solid-liquid separation permits to more effectively obtain the hardly soluble melamine polyphosphate. COPYRIGHT: (C)2004,JPO