Electric insulation with a silicic acid additive made by a melt process

摘要

The invention relates to electric insulation with a polyolefin base for medium and high voltage from about 10 kV up. In insulation of this type the formation of so-called water trees is to be prevented on the one hand and on the other hand, the dielectric losses are to be kept as low as possible. For this purpose it is provided that silicic acid prepared in the following manner is added to the insulation: SiO2-containing mineral substances are melted with additions of aluminum oxide, boron oxide and carbonates and/or oxides of alkali and earth-alkali metals to form a homogeneous glass phase; from the glass melt, glass bodies with a large surface are made; the glass bodies are subjected to a leaching process with mineral acid; the porous SiO2 bodies produced are washed and dried and optionally milled. The electric insulation according to the invention is particularly well suited for use in cables and wires.