▎ 摘　　要

NOVELTY - Low-smoke halogen-free flame-retardant polyolefin sheath material comprises 6-18% ethylene-vinyl acetate copolymer, 4-10% ethylene-octene copolymer, 6-22% metallocene polyethylene, 4-10% compatibility agent, 30-60% aluminum hydroxide, 5-20% magnesium hydroxide, 1-10% shelling agent, 0-4% antioxidant and 0-8% lubricant. USE - The low-smoke halogen-free flame-retardant polyolefin sheath material is useful for building flame-retardant cables. ADVANTAGE - The material has high flame-retardant, low heat release rate, low heat release amount, low smoke-producing rate, drop without delay and excellent performance, meets B1 flame-retardant requirement, and has good mechanical performance, flame retardant performance and processing performance. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing the sheath material, comprising (S1) mixing aluminum hydroxide, magnesium hydroxide, and the shell-forming agent at high speed for the first time according to the measurement, and the additives e.g. adding lubricants, and mixing at a high speed for the second time to obtain compound flame retardant; and (S2) mixing ethylene-vinyl acetate, polyethylene, compatibilizer, metallocene, compound flame retardant, oxidizer and lubricant through an internal mixer and entering the twin-screw extruder from the conical double-screw extruder in a twin-screw extruder unit, mixing, extruding and plasticizing, pelletizing, and drying and cooling.