CROSSLINKING AND PROPERTY MAINTAINING METHOD FOR CROSSLINKED POLYOLEFIN-INSULATING CABLE OR ITS JOINT PART

摘要

PURPOSE:To make it possible to suppress deterioration of dielectric breakdown strength because of trace amount of water by making the atmosphere of a crosslinked polyolefin insulator oxygen-free atmosphere and suppressing decomposition reaction of cumyl alcohol. CONSTITUTION:A composition containing a polyolefin and a peroxide compound as a crosslinking agent is applied on a conductor of a cable or its joint part, and for crosslinking the composition by heating in a sealed area, the coating is heated under an oxygen-free condition in the sealed area produced by putting an oxygen scavenger in the sealed area. In other words, a coating of the composition formed by extrusion is put in a sealed heating container which is connected to a container having an oxygen scavenger through a pipe, oxygen in the container is removed by the oxygen scavenger and put in the latter container and then the coating is heated at the temperature higher than or equal to the decomposition temperature of the crosslinking peroxide compound. As a result, a crosslinked polyolefin-insulating cable having good insulation property is obtained and the insulation property is maintained for a long period.