| 摘要 |
PROBLEM TO BE SOLVED: To provide a high-hardness insulating coating having a good electric characteristic by dry-mixing a base resin made of powdery high-density polyethylene or polypropylene and powdery thermal expansion hollow spherical bodies, extrusion-coating this mixture on a conductor, and foaming it. SOLUTION: Powdery hollow spherical bodies 11 and powdery high-density polyethylene 12 are put in a flow mixer 13 to obtain a mixture 14. The raw material put in the mixing tank of the mixer 13 is stirred, the raw material is pushed upward from a bottom section by centrifugal force, it is lifted along a side wall face and again lowered from a center section, the raw material is circulated in the mixing tank together with air, and the mixing property is improved. The mixture 14 is extrusion-coating on a conductor by an extruding machine 15 and foamed. Since both the base resin 12 and hollow spherical bodies 11 are powdery, the spherical bodies 11 are satisfactorily dispersed and can be highly foamed. Only the base resin 12 having high hardness and a high electric characteristic can be used. |
