Patent ID: 8283031

Claim:
A semiconductive film, wherein the semiconductive film is obtained by: feeding a resin composition to an extruder, the resin composition comprising: poly(ether ether ketone), at most 5 parts by weight, per 100 parts by weight of the poly(ether ether ketone), of other thermoplastic resins, and conductive carbon black having a DBP oil absorption within a range of 30 to 700 ml/100 g in a proportion of 5 to 40 parts by weight per 100 parts by weight of the poly(ether ether ketone), melt-extruding the resin composition in the form of a film from a die, the lip clearance of which has been controlled to at most 1.0 mm, and then cooling and solidifying the film in a molten state at a cooling temperature in a range of 60 to 120° C., wherein the semiconductive film has a degree of crystallinity of poly(ether ether ketone) and the following properties (a) to (c): (a) the average value of its thickness being within a range of 30 to 250 μm, and the maximum value of the thickness being within a range of 1 to 1.3 times as much as the minimum value thereof, (b) the average value of its volume resistivity being within a range of 1.0×10 2 to 1.0×10 14 Ωcm, and the maximum value of the volume resistivity being within a range of 1 to 10 times as much as the minimum value thereof, and (c) the number of reciprocating folds required up to cutting as determined by using a strip-like specimen having a width of 15 mm under conditions of a chuck bending angle of 135° right and left, a folding speed of 175 c/s and a load of 9.8 N per 100 μm of a thickness in accordance with “Testing Method for Folding Endurance by MIT Tester” as prescribed in JIS P 8115 being at least 10,000 times, and wherein the poly(ether ether ketone) is a homopolymer having a structural unit (repeating unit) represented by the following formula (1): or is a copolymer having the structural unit represent by the formula (1), and a structural unit represented by the following formula (2): wherein Q and Q′ may be the same or different from each other and are individually —CO— or —SO 2 —, and n is 0 or 1, and/or a structural unit represented by the following formula (3): wherein A is a divalent lower aliphatic hydrocarbon group, Q and Q′ may be the same or different from each other and are individually —CO— or —SO 2 —, and n is 0 or 1, and wherein the proportion of the structural units represented by the formulae (2) and (3) in the copolymer is at most 10 mol %.