| 摘要 |
<p>PURPOSE:To heighten a mechanical strength with a permittivity lowered as well, by providing an insulating layer, with its foaming degree made high at the core side and continuously getting lower toward outer surfaces, in the highly foamed polyolefine insulated wire. CONSTITUTION:With a highly foaming polyolefine material extruded to the low pressure zone to be coated through a cohesive layer on the core, a temperature of the core during the time until a completion of the polyolefine foaming will be maintained at above a temperature of the low pressure zone. In this way, a foaming degree of the polyolefine will be made high at near the core and successively getting lower as it goes approaching outer surfaces.</p> |
