Abstract: The invention provides a polyester film for the protection of a back surface of a solar cell which, when applied to a silicon thin film solar cell, exhibits excellent durability even under high-temperature and high-humidity conditions and long term thermal stability. The polyester film (a) contains a polyester, as a main constituent, obtained by polymerization using a polycondensation catalyst containing aluminum and/or its compound as well as a phosphorus compound having an aromatic group in the molecule; (b) has a whiteness degree of 50 or higher; (c) contains 3 to 50% by mass of fine particles with a mean particle diameter of 0.1 to 3 ?m; and (d) has an acid value from not lower than 1 (eq/ton) and not higher than 30 (eq/ton).

Abstract: A light diffusion film which has excellent light transmittance and light diffusibility while maintaining excellent heat resistance, mechanical strength and thickness accuracy intrinsic to a biaxially stretched film, and is suppressed in generation of curling after heat treatment, is provided. A light diffusion film consisting of a biaxially stretched laminated film having a supporting layer consisting of a crystalline polyester, and a light diffusion layer laminated on at least one side of the supporting layer by a co-extrusion method, wherein the light diffusion layer comprises 60 to 98 parts by mass of the crystalline polyester and 2 to 40 parts by mass of a light diffusion additive incompatible with the polyester, and the light diffusion film has a planar orientation degree (?P) of 0.080 to 0.160, a total light transmittance of 85% or more, and a haze of 30% or more.

Abstract: The near-infrared ray absorption film of the present invention is a near-infrared ray absorption film in which a near-infrared ray absorption layer comprising a composition containing a near-infrared ray absorbing dye having maximum absorption at a wavelength of 800 to 1200 nm, and a resin is provided on a transparent substrate film, and is characterized that a surfactant having HLB of 2 to 12 is contained in the composition at 0.01 to 2.0% by mass. There can be provided a near-infrared ray absorption film excellent in coated film appearance which has the wide absorbing ability in the near-infrared ray absorbing region, has a high light transmittance in the visible light region, has little change in optical properties with time, and can respond to a higher luminance of a display, and higher-definition and higher image quality by Hi-Vision broadcasting in recent years.

Abstract: A polymerization catalyst for polyester production which contains neither a germanium compound nor an antimony compound as a major component. It contains aluminum as the main metallic ingredient, has excellent catalytic activity, and gives a polyester which is effectively inhibited from suffering thermal degradation, during melt molding, without deactivating or removing the catalyst, and is excellent in thermal stability, stability to thermal oxidation, and hydrolytic resistance. The polymerization catalyst contains as a first metallic ingredient at least one member selected among aluminum and compounds thereof and further contains a phosphorus compound represented by a specific chemical formula. The polyester produced with this catalyst is usable as fibers, films, sheets, various moldings including hollow moldings, etc.

Abstract: A polymerization catalyst for polyester production which contains neither a germanium compound nor an antimony compound as a major component. It contains aluminum as the main metallic ingredient, has excellent catalytic activity, and gives a polyester which is effectively inhibited from suffering thermal degradation, during melt molding, without deactivating or removing the catalyst, and is excellent in thermal stability, stability to thermal oxidation, and hydrolytic resistance. The polymerization catalyst contains as a first metallic ingredient at least one member selected among aluminum and compounds thereof and further contains a phosphorus compound represented by a specific chemical formula. The polyester produced with this catalyst is usable as fibers, films, sheets, various moldings including hollow moldings, etc.