Abstract: Due to the inert surface of basalt fibers and their low bonding strength with the matrix, it is difficult to fully utilize their performance advantages in the preparation of fiber-reinforced composite materials. This paper uses epoxy silicone resin lotion as a film-forming agent, KH-560 as coupling agent and other additives to preparea sizing agent for motifying basalt fibers. Composite insulation materials are prepared by vacuum-assisted molding technology to explore the feasibility of silicone epoxy resin for basalt fiber modification. The results showed that the modification effect of organic silicon epoxy resin on basalt fiber was significant. Compared with composite materials prepared from traditional commercial basalt fiber, its dielectric loss factor was reduced by 31.4%, the surface flashover voltage was increased by 17.88%, and the breakdown field strength was increased by 35.02%, demonstrating superior insulation properties; the bending strength has increased by 16.85%, and it has lower water absorption at 23 ℃ and 100 ℃. Based on the above analysis, the basalt fiber treated with organic silicon epoxy resin exhibits better performance, and the application of basalt fiber reinforced composite materials in large electrical equipment has broad application prospect.

Key words: basalt fiber, sizing agent, surface modification treatment, insulation composite material, performance evaluation