Polyurethane elastomer containing P-C-N symbiotic flame retardant, and preparation method thereof

The invention relates to a polyurethane elastomer containing a P-C-N symbiotic flame retardant, and a preparation method thereof. The preparation method comprises the following steps: putting 55-85% of a thermoplastic elastomer and 0-5% of a lubricant into a high-speed mixer, and performing high-speed dispersion for 2-5 min to obtain a mixture; mixing the mixture with 14.5-40% of an intumescent flame retardant and 0.1-0.5% of an antioxidant for 5-20 min to obtain an intumescent flame-retardant mixture; and extruding and granulating the intumescent flame-retardant mixture by using a double-screw extruder or uniformly mixing by using a double-roller mixing mill to obtain the polyurethane elastomer containing the P-C-N symbiotic flame retardant, wherein the temperature of each region of the double-screw extruder or the temperature of each region of the double-roller mixing mill is set to be 170-230 DEG C. The preparation method has the following advantages: the heat resistance and the water resistance of the fla