ELECTRICAL INSULATION PAPER FOR TECHNICAL PURPOSES AND PROCESS FOR PREPARING THE SAME

摘要

The invention relates to an electrical insulation paper and to a process for preparing the same. The claimed paper is based on coniferous unbleached sulphate cellulose having an aqueous extract electrical conductivity of 38...39 μS/cm and dielectric rigidity in the air of 8.5...8.7 kV/mm at a temperature of 20°C and a dielectric rigidity in the electrical insulation oil of 42.3...43.6 kV/mm at a temperature of 90°C. The claimed process consists in finely grinding a highly-pure cellulose to a grinding degree of 55...60° SR, the paper paste is fed into the papermaking machine with plane sieve having in its circuit demineralized water with a conductivity of maximum 10 μS/cm, and the resulting paper tape is calibrated by calendering at a temperature of 50...60°C and a pressure of 3...4 bar.