A rated voltage 220kv ultra-clean ultra-smooth semi-conductive shielding material and its preparation method

Abstract

The invention provides a rated voltage 220kv ultra-clean ultra-smooth semi-conductive shielding material, comprising: 40-45 parts of EBA or EEA, 16.5-21.5 parts of functional polyolefin, 30-37 parts of clean special conductive carbon black, and a lubricant of 1.7-3.2 parts, 0.3-0.5 parts of antioxidant, 1-2 parts of cross-linking agent. The prepared 220kv semi-conductive shielding material prepared by the invention has good heat resistance, clean surface without bumps, and excellent electrical conductivity.

Description

technical field [0001] The invention belongs to the field of cross-linked polyethylene insulated cable semi-conductive shielding materials, in particular to a rated voltage 220kv ultra-clean and ultra-smooth semi-conductive shielding material and a preparation method thereof. Background technique [0002] At present, due to the limitation of raw material selection, process control, processing equipment and other factors, domestic semi-conductive shielding materials can only meet the market demand for semi-conductive shielding materials with a rated voltage of 35kv and below. [0003] The domestic production of semi-conductive shielding materials of 35kV and below generally uses EVA with appropriate melting index, high-structure conductive carbon black, and white oil as the main raw materials, supplemented by antioxidants, mold release agents, cross-linking agents and other auxiliary materials. agent. The internal mixer is mainly used as the mixing processing equipment, and ...

AI Technical Summary

Problems solved by technology

EVA is used as the base material of semi-conductive shielding materials below 35kv. EVA loses more weight when heated at 260°C than EBA and EEA, and its high temperature stability is not as good as EBA and EEA.

[0005] The traditional 35kv and below semi-conductive shielding materials use conductive carbon black, which is generally domestic furnace carbon black, which has average conductivity and contains more impurities, which cannot meet the electrical performance and cleanliness requirements of 220kv and above semi-conductive shielding materials.

[0006] The preparation of the anti-oxidation-crosslinking system of traditional semi-conductive shielding materials cannot meet the requirements of long-term low-line speed production of 220kv cables

Generally, semi-conductive shielding materials use a traditional single antioxidant, and DCP is used as a cross-linking agent. DCP will decompose rapidly when it exceeds 120°C, and promote cross-linking, resulting in poor extrusion safety of shielding materials.

This is extremely unsafe for 220kv cables that require low speed and long-term production, and it is prone to old glue

[0007] Because the traditional 35kv and below outer shielding material uses EVA with high VA content, its combination with the insulation is not tight enough, and the outer shield can be peeled off

On cables with an AC voltage of 220kv or even higher, the shielding and insulation must be closely connected microscopically, otherwise it will seriously affect the service life of the cable, and the outer screen must not be peeled off, otherwise it will affect the long-term operation of the cable security

[0008] Produced by an internal mixer, the conductive carbon black in the shielding material is difficult to disperse completely and evenly, and it cannot meet the requirements of ultra-clean and ultra-smooth surface of the 220kv cable shielding material

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