Abstract: A plastic film distinguished in corona resistant characteristic having a low cost without a low mechanical strength, which plastic film is particularly suitable for making insulated wires, coils, and electric motors capable of fully responding to demands for providing electric trains with higher running speeds and higher acceleration and deceleration. In accordance with one embodiment, the film includes a base layer and at least one thermally conductive layer having a minimum thermal conductivity of 2 W/m·K, preferably 6 W/m·K, more preferably 15 W/m·K laminated horizontally on at least one surface of the base layer. In accordance with another embodiment, the film has a minimum volume electrical resistivity of 1014 &OHgr;·cm, preferably 1015 &OHgr;·cm, and includes a base layer and at least one low-electrical-resistance layer having a maximum superficial electrical resistance of 1013 &OHgr;·cm, preferably 1012 &OHgr;·CM.