Cable for high-voltage electronic devices
View Patent ↗A cable for high-voltage electronic devices including an inner semiconductive layer, a high-voltage insulator, an outer semiconductive layer, a shielding layer, and a sheath which are provided on an outer periphery of a cable core part in the order mentioned, wherein the high-voltage insulator is made of an insulating composition whose temperature dependence parameter D R found by the following expression is 1.0 or less: D R =log R 23° C. −log R 90° C. (where R 23° C. is volume resistivity (Ω·cm) at 23° C. and R 90° C. is volume resistivity (Ω·cm) at 90° C.). The cable for high-voltage electronic devices is small in diameter and has an excellent withstand voltage characteristic.
1. A cable for high-voltage electronic devices, comprising:
a cable core part;
an inner semiconductive layer provided on an outer periphery of the cable core part;
a high-voltage insulator provided on an outer periphery of the inner semiconductive layer;
an outer semiconductive layer provided on an outer periphery of the high-voltage insulator;
a shielding layer provided on an outer periphery of the outer semiconductive layer; and
a sheath provided on an outer periphery of the shielding layer cable core part, wherein
the high-voltage insulator is made of an insulating composition having a temperature dependence parameter D R defined by the following expression of 1.0 or less:
D R =log R 23° C. −log R 90° C. ,
(where R 23° C. is volume resistivity (Ω·cm) at 23° C. and R 90° C. is volume resistivity (Ω·cm) at 90° C.), and
R 23° C. is not less than 1.0×10 14 Ω·cm nor more than 1.0×10 18 Ω·cm.
2. The cable according to claim 1 , wherein the insulating composition comprises an olefin-based polymer, and dry silica with a specific surface area of not less than 150 m 2 /g nor more than 250 m 2 /g.
3. The cable according to claim 2 , wherein the insulating composition comprises 100 parts by mass of the olefin-based polymer and not less than 0.5 part by mass nor more than 10 parts by mass of the dry silica.
4. The cable according to claim 2 , wherein an average primary-particle diameter of the dry silica is not less than 7 nm nor more than 20 nm.
5. The cable according to claim 2 , wherein pH of a 4% aqueous dispersion liquid of the dry silica is not less than 4 nor more than 4.5.
6. The cable according to claim 2 , wherein the dry silica is fumed silica.
7. The cable according to claim 2 ,
wherein the olefin-based polymer comprises ethylene propylene rubber.
8. The cable according to claim 2 , wherein the olefin-based polymer is crosslinked.
9. The cable according to claim 1 , the cable being a small-diameter cable for high-voltage electronic devices having an outside diameter of not less than 10 mm nor more than 70 mm.