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.

Abstract: The present invention provides a reformed polyimide fluorocarbon resin laminated film having superior adhesive property with metals.The reformed polyimide fluorocarbon resin laminated film according to the present invention is constructed by that a surface of fluorocarbon resin of polyimide fluorocarbon resin laminated film having fluorocarbon resin being laminated on a single surface or both surfaces of a polyimide film is coated with a coupling agent, or executed with corona treatment.

Abstract: The object of the invention is to embody further thinning of a double layer flexible printed circuit board (FPC) and provide a flexible copper-coated laminate capable of producing such a novel flexible printed circuit board distinguished in bending characteristic and heat-resistant property and provide a printed circuit board using the novel flexible copper-coated laminate. To achieve the above object, novel flexible copper-coated laminates 10 and 12 according to the present invention are respectively composed by directly forming a copper layer 16 having a thickness of 10 .mu.m or less than 10 .mu.m on a single surface or both surfaces of polyimide film 14 which is composed of polyimide polymer containing modulus of initial tensile elasticity of 400 kg/mm.sup.2 or more than 400 kg/mm.sup.2, and which has a thickness of 10 .mu.m or less than 10 .mu.m.

Abstract: A resin film useful mainly for fabricating flexible printed circuits, and a method of producing same. In the process of fabricating a flexible printed circuit board, a copper foil(2) is thermally bonded to a resin film(1), and the copper foil(2) is then etched to a predetermined pattern, in which case the board is generally subject to some dimensional change. In order to minimize such dimensional change it is arranged that the ratio(a/b) of the linear expansion coefficient(a) of the resin film(1) in the direction of mechanical feed(MD direction) to the linear expansion coefficient(b) of the resin film(1) in a direction perpendicular to the MD direction (TD direction) is more than 0.2 but less than 1.0 and that the linear expansion coefficient in MD direction is 0.4-2.0.times. 10.sup.-5 .degree..sup.-1. For such resin film is used a polyimide film containing more than 90% of a recurring unit expressed by a specified general formula. To produce such a resin film, film 1 is drawn by a factor of from 1.0 to 1.

Abstract: The present invention provides a polyimide film whose residual content of volatiles is reduced to not more than 0.45 weight % on the basis of the film, and further a polyimide film whose residual content of volatiles is reduced to not more than 0.45 weight % on the basis of the film and whose oxygen/carbon ratio in the surface layer is increased by 0.01-0.1, and manufacturing methods therefor.According to the present invention, it is possible to provide a polyimide film improved in adhesion performance in a stable and homogeneous manner, and this improvement of adhesion performance is attainable in the film-forming process, not in a separate process of after-treatment.