Foamed electric wire and transmission cable having same

摘要

The foamed electric wire with a conductor and a foamed insulation layer covering the conductor; the foamed insulation layer is obtained by kneading a base resin composed of a high melting point propylene-based resin having a melting point of 150° C. or higher with a master batch containing a thermally decomposing chemical foaming agent and a low melting point propylene-based resin having a melting point of 135° C. or lower and melting the low melting point propylene-based resin followed by foaming by inducing thermal decomposition of the thermally decomposing chemical foaming agent, and a compounding ratio of the low melting point propylene-based resin in the entire resin component formed of the high melting point propylene-based resin and the low melting point propylene-based resin is less than 20% by mass.

主权项

1. A foamed electric wire, comprising:
a conductor; and a foamed insulation layer covering the conductor, wherein the foamed insulation layer is obtained by: kneading a base resin formed of a high melting point propylene-based resin having a melting point of 150° C. or higher with a master batch containing a thermally decomposing chemical foaming agent and a low melting point propylene-based resin having a melting point of 125° C. or higher and 135° C. or lower and being a random copolymer, and melting the low melting point propylene-based resin, followed by foaming by inducing thermal decomposition of the thermally decomposing chemical foaming agent; and a compounding ratio of the low melting point propylene-based resin in the entire resin component formed of the high melting point propylene-based resin and the low melting point propylene-based resin is less than 20% by mass.