| 摘要 |
The invention is to provide a polyester film excellent in moist heat resistance and other characteristics (ultraviolet ray resistance, light reflecting characteristic, etc.), and to provide a solar battery backsheet excellent in moist heat resistance and ultraviolet ray resistance by using the polyester film. It is also a task to provide a highly durable solar battery by using the solar battery backsheet. The polyester film is a polyester film containing particles and two kinds of crystalline polyester resins in which a sea-island structure is formed, and being characterized in that if a crystallization temperature of a crystalline polyester resin that forms a continuous phase (also referred to as matrix phase) (hereinafter, referred to as crystalline polyester resin A) is represented by TccA and a crystallization temperature of a crystalline polyester resin that forms a dispersion phase (also referred to as domain phase) (hereinafter, referred to as crystalline polyester resin B) is represented by TccB, an expression (1) below is satisfied, and that a degree of flatness of the dispersion phase is 3 or more, and that 70% or more of a total number of the particles are present in the dispersion phase or are in contact with the dispersion phase. TccA - TccB ‰¥ 5 �¢ °C |
