Preparation method of low-smoke non-halogen flame-retardant material for high-voltage cable sheath

Abstract

The invention discloses a preparation method of a low-smoke non-halogen flame-retardant material for a high-voltage cable sheath. The preparation method comprises the following steps of: mixing inorganic flame retardants magnesium hydroxide and aluminum hydroxide in a high-speed mixer at high rotation speed of 900 rpm-1100 rpm until the temperature is 80 DEG C-90 DEG C, dehydrating, and utilizing a 172 silane coupling agent to carry out spraying process; adding the inorganic flame retardant magnesium hydroxide, aluminum hydroxide and metallocene polyethylene ethylene vinyl acetate copolymer the melt index of which is 2-8, acroleic acid grafting high density polyethylene, organic silicon cave, molybdenum disulfide, an antioxygen as well as a lubricating agent after the 172 silane coupling agent treatment in a masticator so as to knead; when the temperature of material to be kneaded rises to 125 DEG C-135 DEG C, placing the kneaded lumpish material to an elevator so as to deliver the material a fusant cone feeding machine, using the feeding machine to place the material in a dual-screw rod extruding machine to carry out extrusion and milling, and enabling the extruded and milled material to enter a single-screw rod extruding machine so as to manufacture granules; and adopting a die surface hot cutting granulating process, enabling the manufactured granules to enter a first-stage whirlwind cooling segregator, a second-stage whirlwind cooling segregator, an air cooling oscillating screen and a third-stage whirlwind cooling segregator through a fan transfer pipeline, thus obtaining finished material. Such prepared sheath material has the advantages of high mechanical property, good wearability and cohesive property, so that when a cable is installed and laid, a cable sheath layer is not easy to abrade and rupture.

Description

technical field [0001] The invention relates to a preparation method of a low-smoke, halogen-free flame-retardant material for a high-voltage cable sheath. Background technique [0002] Due to the effect of high-voltage electric field and mechanical protection, high-voltage power cables need to extrude plastic sheath material on the outer layer of the cable. Usually, the sheath material of high-voltage power cables is made of black polyethylene material, and the outer surface is coated with conductive graphite or conductive polyethylene to prevent High-voltage induced voltage breakdown, reducing surface induced voltage. However, with the underground laying of urban high-voltage power grid lines, cables are required to have low-smoke, halogen-free and flame-retardant functions. Therefore, the material for preparing cable sheaths must be low-smoke, halogen-free, and flame-retardant black polyethylene materials. Smoke-free halogen-free flame-retardant sheath materials usually ...

AI Technical Summary

Problems solved by technology

However, due to the low mechanical strength and hardness of the ethylene vinyl acetate copolymer material, the material has low mechanical strength and poor wear resistance, resulting in damage to the cable surface sheath during the installation and laying of the cable, especially for large cross-section cables. Once the cable sheath is broken, it may cause the instability of the power grid system, and the cable body will be subjected to various damages, which cannot effectively protect the effective operation of the cable; moreover, the existing low-smoke, halogen-free and flame-retardant sheath materials have poor adhesion, resulting in The conductive graphite layer or conductive polyethylene layer on the surface will fall off, so that the partial discharge current of the cable cannot be effectively released, affecting the effective use of high-voltage cables