▎ 摘　　要

NOVELTY - Preparation method of polyolefin shielded cable material involves (a) blending graphene with potassium acetate and foaming agent, adding washing agent and cleaning, (b) placing the mixture in a vacuum environment and adding deionized water to crush, (c) drying the crushed material, grinding, washing with water, heating and cooling, and (d) mixing modified graphene with poly(4-methyl-1-pentene), ethylene-vinyl acetate, ethylene bis(stearamide), tribasic lead sulfate, zinc oxide and dibutyl maleate and carrying out plasticizing granulation to obtain a composite filler masterbatch. USE - Method is useful for the preparation of polyolefin shielded cable material (claimed). ADVANTAGE - The method enables simple preparation of the low-smoke halogen-free polyolefin shielded cable material with excellent corrosion resistance, flame retardant property, heat resistance, water resistance and wear resistance, high dispersibility and prolonged service life. DETAILED DESCRIPTION - Preparation method of polyolefin shielded cable material involves (a) blending graphene with potassium acetate and foaming agent, putting the mixture into an ultrasonic cleaning machine, adding a washing agent and cleaning 10-12 times for 10-20 minutes in each time to obtain a mixture, where the weight ratio of graphene, potassium acetate and foaming agent is 3:4-6:0.04-0.06, (b) placing the mixture in a vacuum environment, leaving for 4-5 hours, taking out and adding deionized water to crush, (c) drying the crushed material at 60-65 degrees C, taking out, grinding for 1-2 minutes, washing with water, drying, putting into a muffle furnace, heating at 900-950 degrees C for 4-4.3 hours and cooling to obtain modified graphene, (d) mixing the modified graphene with poly(4-methyl-1-pentene), ethylene-vinyl acetate, ethylene bis(stearamide), tribasic lead sulfate, zinc oxide and dibutyl maleate in a high-speed mixer under stirring condition at a high speed of 1500-2000 rpm for 4-8 minutes, adding the mixture to a twin-screw extruder and carrying out plasticizing granulation to obtain a composite filler masterbatch, and (e) heating the extruder at 130-150 degrees C, adding low-density polyethylene, triphenyl phosphate, dioctyl phthalate, inorganic nano-flame retardant and activated calcium carbonate, mixing for 3-5 minutes, then adding precipitated white carbon black, stearic acid, 2,4-dichlorobenzoyl peroxide, ammonium molybdate, 2,2'-thiodiethylene bis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) and composite filler masterbatch, mixing for 4-6 minutes, extruding, granulating, sieving by a vibrating screen and cooling to obtain the finished product.