Crystalline aluminum phosphite, preparation method and application thereof

Abstract

The present invention discloses a crystalline aluminum phosphite, a preparation method thereof and an application thereof as or for the preparation of a flame retardant or a flame retardant synergist. The preparation method has the following processes: 1, reacting aluminum hydrogen phosphite with an aluminum-containing compound in water at 80-110° C. to obtain a precipitate in the presence of no strong acid or a small amount of strong acid; 2, washing and filtering the precipitate; 3, drying the precipitate at 100-130° C.; 4, continuously heating the dried solid step by step at a low speed, where the material temperature is increased to not exceeding 350° C. from room temperature at about 5-10 h, with a temperature rise rate not exceeding 5° C./min. Compared with amorphous aluminum hydrogen phosphite, the crystalline aluminum phosphite has a higher thermal decomposition temperature, lower water absorption and weaker acidity, and can be synergistic with diethyl aluminum hypophosphite to achieve better flame retardant property and thus, is used for a halogen-free flame retardant component of high polymer materials.

Dependencies are inferred from the claim text.