Post-absorption process of peroxide cross-linking polyethylene insulating material

Abstract

The invention relates to an insulating material for electric power cables, in particular to a post-absorption process of a peroxide cross-linking polyethylene insulating material. The process comprises the following steps of: (1) material blending: antioxidant and polyethylene are blended; (2) mixing and pelletizing: the blended materials are mixed in a mixing roll, and the mixed materials are filtered and then extruded and pelletized; (3) dehydrating and drying: the materials derived from pelletizing in the step 2 are dehydrated and dried to obtain an intermediate; (4) remixing: the intermediate derived from the step 3 is mixed with a peroxide cross-linking agent for 5 to 240 minutes at the temperature from 50 DEG C to 80 DEG C; (5) post-absorbing: the material derived from the step 4 is post-absorbed; and (6) cooling: the material derived from the step 5 is cooled to obtain the peroxide cross-linking polyethylene insulating material. The process in the invention is uniform in mixing, good in post-absorption effect and simple and reasonable in process; and the manufactured insulating material has reliable performances and good quality.

Description

technical field [0001] The invention relates to an insulating material for power cables, in particular to a post-absorption process for a peroxide crosslinked polyethylene insulating material. The peroxide cross-linked polyethylene insulating material produced by this process is suitable for high, medium and low voltage power cables, especially for 35kV and below power cables. Background technique [0002] The English name of polyethylene is polyethylene, referred to as PE, which is a thermoplastic resin obtained by polymerization of ethylene. In industry, it also includes copolymers of ethylene and a small amount of α-olefins. Polyethylene is odorless, non-toxic, feels like wax, has excellent low temperature resistance, the lowest operating temperature can reach -70 ~ -100 ° C, good chemical stability, can withstand the erosion of most acids and alkalis, and is not resistant to oxidizing properties. Acid, insoluble in common solvents at room temperature, low water absorp...

AI Technical Summary

Problems solved by technology

This makes: (1) It is impossible to mix polyethylene and high-melting-point antioxidant at a higher temperature, so that the high-melting-point antioxidant cannot be fully melted and effectively dispersed, so that the mixing of antioxidant and polyethylene is difficult. Uniformity, powdery spots and other phenomena appear, so that the stability and reliability of the insulating material deteriorate, and the electrical performance decreases; (2) It is impossible to mix polyethylene and high melting point antioxidant at a higher temperature, which makes the melting The viscosity of the melt is high and the pressure is high, so it is impossible to filter the impurities in the raw material (such as adding a filter, etc., the low-temperature and high-viscosity melt cannot pass through the filter and purification equipment such as the filter), so there is no filtration step in the traditional post-absorption process , the insulating material produced has high impurity content, poor cleanliness, and poor electrical insulation performance; (3) There is a slight decomposition of DCP in the extrusion granulation process, resulting in pre-crosslinked materials, resulting in a decline in product quality

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