Thermoplastic oil-resistant halogen-free low-smoke flame-retardant polyolefin cable material and preparation method thereof

Abstract

The invention relates to a thermoplastic oil-resistant halogen-free low-smoke flame-retardant polyolefin cable material. The material is characterized in that: the material is prepared from raw materials of: substrate resin, a fire retardant, a lubricating agent, and an anti-oxidant. The substrate resin is composed of metallocene linear low-density polyethylene (MLLDPE), an ethylene-vinyl acetate polymer, and an interface compatibilizing agent. The preparation method comprises the steps that: the raw materials are well mixed in a high-speed mixing machine; the mixture is subjected to mixed extrusion under a processing temperature of 125-145 DEG C on a same-direction double-screw extruder; and the material is subjected to hot-cut granulation, such that a finished product is obtained. Compared with a traditional thermoplastic halogen-free low-smoke flame-retardant polyolefin cable material, the cable material provided by the invention has good oil resistance. When the cable material is soaked in mineral oil, the change rates in tensile strength and breaking elongation are low.

Description

technical field [0001] The invention relates to a thermoplastic oil-resistant, halogen-free, low-smoke, flame-retardant polyolefin cable material and a preparation method thereof, belonging to the technical field of materials for wire and cable insulation and sheathing (cable material for short). Background technique [0002] Traditional halogen-free low-smoke flame-retardant polyolefin cable materials mostly use ethylene-vinyl acetate copolymer (EVA) as the main resin base material, supplemented by a small amount of linear low-density polyethylene (LLDPE) to improve the high-temperature deformation resistance of the cable material sex. Among them, ethylene-vinyl acetate copolymer is made by copolymerization of ethylene (E) and vinyl acetate (VA), referred to as EVA, which has good softness and elasticity. It is solid at room temperature, and when heated and melted to a certain extent, it becomes a fluid with a certain viscosity. Linear low density polyethylene is produced...

AI Technical Summary

Problems solved by technology

[0003] The traditional halogen-free low-smoke flame-retardant polyolefin cable material is thermoplastic if it does not need to be cross-linked by radiation, that is, thermoplastic halogen-free low-smoke flame-retardant polyolefin cable material, but this thermoplastic halogen-free low-smoke flame-retardant polyolefin cable It is difficult for the material to pass the mineral oil immersion test in GB / T 2951.21-2008, that is, its resistance to mineral oil is poor, so this product cannot be used in environments with mineral oil such as tank trucks and oil pipelines, making it suitable for Occasions are restricted

The reason for the poor oil resistance of traditional thermoplastic halogen-free low-smoke flame-retardant polyolefin cable materials is that the EVA in the raw material is affected by vinyl acetate monomer, and the crystallinity is relatively low, resulting in a large swelling rate of EVA in mineral oil, that is, poor oil resistance

In addition, in order to ensure the characteristics of halogen-free and low-smoke flame retardancy, inorganic flame retardants should be added to this cable material, and inorganic flame retardants will also destroy the crystal area, so that the thermoplastic halogen-free low Mineral oil resistance of smoke flame retardant polyolefin cable compound is very poor

As far as LLDPE is concerned, it has a high degree of crystallinity, so its mineral oil resistance is better than EVA under the same conditions. Thermal cracking performance cannot meet the requirements of national standards