Abstract：Methyl hydrogen polysiloxane fluid was used as modifier, activated clay as catalyst, talcum powder, mica powder and hydrophobic silica as accessories, by the detection of hydrophobic retention, moisture content, hygroscopicity and fluidity, the effect of methylhydrosilicone fluid, hydrophobic silica addition time and adding method, modification temperature, talc powder and mica powder on the modification of superfine ammonium polyphosphate were studied. The results show that when the amount of methyl hydrogen containing silicone oil is 12 g, the hydrophobicity retention rate of modified superfine ammonium polyphosphate is 94.5%. The stirring rate should be followed by first increase after the decrease and then increase. After methyl hydrogen polysiloxane fluid cross-linking polymerization, hydrophobic silica must be added at once.Modified temperature includes the dispersion temperature55~60 ℃, film temperature 100~105 ℃. Compared with the traditional fire extinguishing material ammonium dihydrogen phosphate modification process, the activated clay do not change the hydrophobicity of the material.

Keywords：superfine ammonium poly-phosphate; methylhydro silicone fluid; hydophobic modification