MELAMINE MELAM MELEM DOUBLE SALT OF A POLYPHOSPHORIC ACID AND PROCESS FOR ITS PRODUCTION

摘要

A melamine.cndot.melam.cndot.melem double salt of a polyphosphoric acid, which has a solubility of from 0.01 to 0.10 g/100 ml in water (25.degree.C), a pH of from 4.0 to 7.0 as a 10 wt% aqueous slurry (25.degree.C), and a melamine content of from 0.05 to 1.00 mol, a melam content of from 0.30 to 0.60 mol and a melem content of from 0.05 to 0.80 mol, per mol of the phosphorous atom; and A process for producing the above mentioned melamine.cndot. melam.cndot.melem double salt of a polyphosphoric acid, which comprises the following steps (a) and (b): (a) a step of obtaining a reaction product by mixing melamine and phosphoric acid at a temperature of from 0 to 330.degree.C in such a ratio that the melamine is from 2.0 to 4.0 mols per mol of the phosphoric acid (as calculated as orthophosphoric acid content), and (b) a step of baking the reaction product obtained in step (a) at a temperature of from 340 to 450.degree.C for from 0.1 to 30 hours.