| 摘要 |
PROBLEM TO BE SOLVED: To obtain a composition having excellent water tree resistance by mixing a crosslinked polyethylene with a poly-N-vinylacetamide in a specified ratio. SOLUTION: There is provided a composition comprising a crosslinked polyethylene and 0.1-10.0 wt.% poly-N-vinylacetamide represented by the formula. This composition is used in the internal and external semiconductive layers of a power cable as well as in the insulation layer of a power cable. The crosslinked polyethylene used is a hydrophobic polymer obtained by subjecting a low-density polyethylene, a high-density polyethylene, or the like to crosslinking by irradiation with high-energy electron beams orγ-rays, silane graft water crosslinking, chemical crosslinking, or the like and easily suffers from water deposition by dielectric condensation on a non-uniform electric field part which acts as a point of the generation of water tree. On the contrary, the poly-N-vinylacetamide is a hydrophilic thermoplastic polymer and makes it difficult for water to condense and deposit on a point of the generation of water tree on the hydrophobic polymer. |
