Disclosed in the present invention are a 90°C
thermoplastic halogen-free low-
smoke flame-retardant
polyolefin sheath material and a preparation method therefor. The sheath material is prepared from raw materials comprising the following components in parts by
mass: 20-40 parts of an
ethylene-
vinyl acetate copolymer, 20-40 parts of a linear low-density
polyethylene, 2-10 parts of a high-density
polyethylene, 20-40 parts of a
metallocene ethylene-octylene
copolymer, 10-15 parts of a maleic-anhydride-grafted
metallocene linear low-density
polyethylene copolymer, 58-73 parts of aluminum
hydroxide, 20-25 parts of modified
magnesium hydroxide, 64-84 parts of a synergistic
flame retardant, 2-3 parts of a
coupling agent, 1-4 parts of a
lubricant, 1-3 parts of an
antioxidant, and 2-7 parts of a coloring agent, wherein the synergistic
flame retardant comprises
lithium oxide. A matrix resin has low-temperature performance, mechanical properties and
cracking resistance. With regard to flame retardance, a large amount of the synergistic flame retardant, i.e.,
lithium oxide, is added to a traditional
magnesium-aluminum compound flame-retardant
system, and therefore an off-white hard shell can be formed during a
combustion process while low heat release is ensured, thereby ensuring no dripping during the
combustion process.