Preparation method of high-voltage and ultrahigh-voltage cable insulating material

Abstract

The invention discloses a preparation method of a high-voltage and ultrahigh-voltage cable insulating material. The preparation method comprises the following steps: (1) compressing an ethylene monomer, carrying out high-pressure polymerization in a reactor to obtain low-density polyethylene, separating by a high-pressure separator and a low-pressure separator, cooling the low-density polyethylene, directly feeding into a single-screw extruder, adding a liquid antioxidant, uniformly dispersing the liquid antioxidant into low-density polyethylene, filtering through a high-mesh filter screen, and granulating to obtain low-density polyethylene containing the antioxidant; and (2) dedusting and grading the antioxidant-containing low-density polyethylene, adding a cross-linking agent by adoptinga post-permeation method, fully stirring, putting into an absorption bin, keeping the temperature, cooling, dedusting, removing impurities, and carrying out metal filtration to obtain the high-voltage and ultrahigh-voltage cable insulating material. According to the method provided by the invention, secondary melting processing of low-density polyethylene is avoided, thermal aging of resin is reduced, the cleanliness and the stability of the insulating material are improved, and the method is high in production efficiency, low in cost and convenient to popularize and apply.

Description

technical field [0001] The invention relates to a method for preparing high-voltage and ultra-high-voltage cable insulation materials, and belongs to the technical field of insulation material processing. Background technique [0002] At present, the high-voltage cable insulation materials at home and abroad are mainly cross-linked polyethylene materials. The preparation process is to mix low-density polyethylene with an appropriate amount of solid antioxidant through a twin-screw or reciprocating single-screw extruder to ensure that the antioxidant is uniform. The resin is dispersed in the low-density polyethylene resin. After the resin is filtered through a high-mesh filter, pelletized by an underwater pelletizer, and dried, it is combined with a cross-linking agent to infiltrate the process to achieve ultra-clean and low-scorch production of high-voltage cable insulation materials. . The disadvantages of this method are: 1. The screw structure of the reciprocating single...

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Problems solved by technology

The disadvantages of this method are: 1. The screw structure of the reciprocating single-screw extruder is complicated, the process is complicated, and the equipment cost is high. The secondary melting process of the resin has a certain influence on the quality and performance of the resin; 2. The process of the twin-screw extruder is simple, Due to low-temperature strong shearing, high local temperature, and material retention, the low-density polyethylene molecules are destroyed, thermally aged, and crystal points, color particles, etc. appear, which seriously affect the quality of insulating materials; 3. In order to reduce resin aging, double Screw extruders and reciprocating single-screw extruders generally have a continuous production time of no more than 7 days, and the production efficiency is low, and cleaning equipment and environmental systems is time-consuming and laborious, resulting in high production and maintenance costs

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