Natural rubber and synthetic rubber have high electrical resistivity and are poor conductors of electricity. They can be used to produce electrical insulation products, such as wires and cables, insulating sheaths, high-voltage wires, high-voltage caps, insulating tapes, insulating gloves and other products. widely used. In actual production, EPDM reclaimed rubber can be used with ethylene propylene rubber to produce low-cost electrical insulating rubber products. Reasonable design of EPDM rubber/reclaimed rubber insulating compound formula can further improve the electrical insulation of EPDM reclaimed rubber products.
1. Vulcanization system design
When using EPDM reclaimed rubber/original rubber to prepare electrical insulating rubber compound, it is recommended to choose peroxide vulcanization or quinone oxime vulcanizing agent. The vulcanized rubber has better electrical insulation and heat resistance. When peroxide (common DCP) is used to vulcanize EPDM 2YLYY719 rubber compound, DCP can be used together with triallyl cyanurate, diphthaloyl quinone dioxime, and a small amount of sulfur to further improve the Electric insulation performance of C reclaimed rubber.
2. Filling system design
The amount of rubber filler in the electrical insulating compound is second only to the raw rubber, so the type and amount of filler have a greater impact on the insulation performance of EPDM reclaimed rubber vulcanizate. In actual production, when the amount of carbon black with high structure and large specific surface area is large, it is easy to form conductive channels, resulting in a decrease in the electrical insulation performance of the rubber compound. Therefore, it is not recommended to use carbon black. When EPDM reclaimed rubber is used together with virgin rubber to prepare electrical insulating rubber, it can be filled with inorganic fillers such as clay, talc, calcium carbonate, mica powder, and white carbon black.
When selecting fillers for EPDM electrical insulating compounds, special attention should be paid to the water absorption and water content of the fillers. Fillers with strong water absorption or moisture will cause the electrical insulation performance of EPDM vulcanizates to decrease. When using EPDM reclaimed rubber/raw rubber to produce high-voltage electrical insulating rubber products, it is recommended to use talcum powder, calcined clay or surface-treated clay; low-voltage electrical insulating rubber can choose calcium carbonate, talcum powder and ordinary clay.
The amount of vulcanizing agent and the particle shape of the rubber filler will affect the electrical insulation of the EPDM/raw rubber combined rubber, especially the breakdown voltage strength. For example, the flaky filler can form an obstacle to prevent breakdown in the electrical insulating rubber, so that the breakdown route cannot proceed in a straight line. Therefore, the breakdown voltage strength of the flaky talc and mica powder is relatively high. In actual production, the variety and dosage of softeners and antioxidants will also affect the electrical insulation of EPDM reclaimed rubber. The editor will continue to discuss related issues with you tomorrow.
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