▎ 摘　　要

NOVELTY - Heat-conducting and flame-retardant polyolefin-based composite material comprises 75-80 pt. wt. polypropylene, 12-18 pt. wt. styrene-ethylene-butadiene-styrene block copolymer, 7-9 pt. wt. maleic anhydride grafted polypropylene, 5 pt. wt. modified graphene, 12-15 pt. wt. modified boron nitride fiber, 2-4 pt. wt. epoxy-terminated hyperbranched auxiliary agent, 1-2 pt. wt. antioxidant, 10-13 pt. wt. ammonium polyphosphate. The epoxy-terminated hyperbranched auxiliary agent is prepared by adding hyperbranched polymer into dimethylformamide, adding boron trifluoride ethyl ether, adding epichlorohydrin under stirring, heating to 65℃ for 2 hours, removing unreacted epichlorohydrin and dimethylformamide by rotary evaporation, transferring mixture to reactor, adjusting pH to 8-9 by dropwise addition of sodium hydroxide solution, heating temperature to 80℃, maintaining reaction for 3 hours, extracting liquid, separating and distilling organic phase under reduced pressure. USE - The composite material is useful for cable material used in vehicle. ADVANTAGE - The composite material has limiting oxygen index of more than 37% and thermal conductivity of more than 2 W/m.K; improves the service life of the cable when used in cable material, and reduces the safety hazard. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a method for preparing heat-conducting and flame-retardant polyolefin-based composite material comprising (1) mixing polypropylene, styrene-ethylene-butadiene-styrene block copolymer, maleic anhydride grafted polypropylene, modified graphene, and modified boron nitride fibers, adding epoxy-terminated hyperbranched auxiliary agent, antioxidant, ammonium polyphosphate, and continue stirring to obtain a mixture, and (2) extruding and granulating the mixture with a twin-screw extruder to obtain a heat-conducting and flame-retardant polyolefin-based composite material.