Abstract: A biaxially oriented saturated polyester film made by a biaxial orientation method, includes a heat-seal side formed in at least one of two sides of the film, the heat-seal side being made by applying a low-temperature plasma treatment to a film surface so that the film surface has a composition ratio of the number of oxygen atoms to the number of carbon atoms, the composition ratio being not less than 105% and not more than 115% of a theoretical value and so that the heat-seal side is heat sealable at a heating temperature ranging from 100° C. to 200° C.

Abstract: A biaxially oriented saturated polyester film made by a biaxial orientation method, includes a heat-seal side formed n at least one of two sides of the film, the heat-seal side being made by applying a low-temperature plasma treatment to a film surface so that said heat-seal side is heat sealable at a heating temperature ranging from 100° C. to 200° C.

Abstract: Disclosed is a polyimide film laminate which has a high interlayer peeling strength and which is easily fabricated. The polyimide film laminate in which polyimide films are laminated and bonded to each other, is characterized in that at least two polyimide films each subjected to a plasma surface treatment are superposed and thermocompressively bonded to each other and in that the interlayer peeling strength between the films is at least 0.3 kgf/cm.