POLYESTER FILM CONTAINING CAVITY

摘要

PROBLEM TO BE SOLVED: To provide a polyester film containing cavities which can efficiently attain high reflectance in a visible light region by controlling the shape or the number of cavities present in the film, can prevent the deposition of dirt or dust on the surface, and can eliminate the inconvenience due to the charge when processed and prevent the falling down of the particles by providing an antistatic layer and is suitably used as a base material for a reflector for a liquid crystal display or an internal lighting type illumination signboard. SOLUTION: The polyester film containing the cavities includes a polymer mixture containing a polyester and an amorphous circular olefin copolymer immiscible with the polyester and has fine cavities, wherein the ratio (L1/T1) of the average length (L1) to the average thickness (T1) in the cross-section formed by cutting the film vertically to the surface is ≥10, the number of the cavities per 1,000 μm2cross sectional area is ≥60, and the polyester film containing the cavities is provided with the antistatic layer having a reflectance in the 560 nm wavelength of ≥95% with respect to at least one surface of the film and having ≤5×1010Ω/sq surface specific resistance at 23°C and 50% relative humidity with respect to at least one surface of the film. COPYRIGHT: (C)2009,JPO&INPIT