Mine cable insulation shielding material and preparation method thereof

Abstract

A mine cable insulation shielding material comprises the following compositions in parts by weight: 100 parts of ethylene-vinyl acetate copolymer (EVA), 50-100 parts of conductive carbon black, 1-4 parts of a cross-linking agent, 1-4 parts of an auxiliary crosslinking agent, 5-15 parts of a lubricant, 5-25 parts of a softener, 1-3 parts of an anti-oxidant, and 1-3 parts of an anti-ageing agent. The preparation steps of the material comprises: a, weighing the raw materials for usage; b, blending, concretely uniformly blending conductive carbon black, the lubricant, the softener, the anti-oxidant and the anti-ageing agent, so as to obtain a mixture for usage; c, mixing, adjusting the roller distance of an open mill to be 1-2 mm, adding EVA, after rolling is finished, adding the mixture, mixing for 8-10 min, then adding the crosslinking agent and the auxiliary crosslinking agent, and mixing for 2-3 min, keeping the roller temperature to be 65-75 DEG C in the rubber mixing process, and controlling the mixing time to not exceed 20 min, and performing thin passing for five times, and discharging a sheet.

Description

technical field [0001] The invention relates to a mining cable insulation shielding material, in particular to a strippable mining cable insulation shielding material used for rubber insulation and a preparation method thereof. Background technique [0002] The conductor and insulation of medium and high voltage rubber insulated mining cables require semi-conductive shielding materials. The function of the shielding material is to make the electric field distribution on the cable insulation layer uniform, reduce the electrical stress of the insulation layer, and prevent corona discharge. [0003] The semi-conductive shielding material is mainly prepared by adding conductive carbon black and other auxiliary additives with conductive properties to the organic polymer matrix. At present, rubber insulation shielding materials usually use halogen-containing high polymers such as neoprene rubber (CR), chlorosulfonated polyethylene (CSM) or chlorinated polyethylene (CPE), nitrile ...

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Problems solved by technology

However, nitrile rubber (NBR) is an unsaturated rubber with poor heat aging resistance. In addition, it is easy to generate heat during mixing, especially when a large amount of conductive carbon black is added, and the heat generation is more obvious. In-machine mixing, labor-intensive

When ethylene-vinyl acetate polymer (EVA) is used, in order to make it have good peelability with the insulating layer, the content of vinyl acetate should not be lower than 33wt%, and most of them are used together with NBR as the base material, and EVA / NBR is used together The semi-conductive shielding material (WO-0229829) made of glue, after heat aging, will cause the adhesive force between the insulating shielding layer and the insulating layer to lose significantly. This loss of adhesion is particularly severe if the insulating material contains low molecular species that do not readily crystallize on cooling

Adhesion loss causes cables not to meet specification and creates commercial problems

Using EVA with high vinyl acetate (VA) content to provide strippability is not only costly, but the high content of vinyl acetate in it produces acetic acid which can cause processing problems as described in WO-0229829, equipment corrosion , sintering and high cost

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