Preparation method of novel silicane fire retardant

The invention relates to a preparation method of novel silicane fire retardant. The method includes the following steps of firstly, dissolving siloxane in organic solvent with the siloxane as raw materials, adding a potassium hydroxide catalyst, and conducting heating reflux for 15-30 minutes after the mixture is stirred to be uniform so that sodium complex can be obtained; secondly, adding phosphorus trichloride for substitution after the phosphorus trichloride is slightly cooled, conducting reflux again for 25-40 minutes, and converting the phosphorus trichloride into phosphorus complex; thirdly, conducting filtering after cooling, cooling filtrate to -5 DEG C after the filtrate is concentrated, and generating white crystals; fourthly, flushing the white crystals obtained in the third step through methyl alcohol, placing the white crystals in a room-temperature vacuum oven to be dried for 0.6-1.5 hours, and obtaining the silicane fire retardant. Compared with the prior art, the reaction condition is gentle, the reaction temperature is moderate, the obtained finished product can be quite easily separated from a reaction system, the flame retardant property and the oxidation resistance can be effectively improved, and meanwhile the mechanics performance, the insulating performance and the heat resistance are not influenced.