LAYERED POLYESTER FILM, PROCESS FOR PRODUCING SAME, PROTECTIVE SHEET FOR SOLAR CELL, AND SOLAR CELL MODULE

摘要

The layered polyester film according to an embodiment of the present invention comprises: a biaxially stretched polyester film produced by stretching an unstretched polyester film in a first direction and stretching the resultant film in the second direction that is perpendicular to the first direction along the film surface, the biaxially stretched polyester film, when examined by differential scanning calorimetry, showing a minute peak at a temperature of 160-210°C, the minute peak being attributable to thermal fixation temperature; and an undercoat layer having an elastic modulus of 0.7 GPa or greater and formed by applying a composition for undercoat layer formation to one surface of the polyester film which has been stretched in the first direction but which has not been stretched in the second direction and then allowing the coating to undergo stretching in the second direction. Also provided are a process for producing the layered polyester film, a protective sheet for solar cells which includes the layered polyester film, and a solar cell module.