| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a polyester film excellent in slidability, adhesion and weather resistance, a method for producing the same, a back sheet for solar cell having high adhesion and weather resistance, and a long-lived solar cell module. <P>SOLUTION: Raw material polyester having an inherent viscosity of 0.70-1.0 dL/g and a terminal carboxyl concentration of 20 equiv./ton is melt and extruded to form an undrawn film, the undrawn film is drawn in the longitudinal direction and then drawn in the width direction to obtain a biaxially-drawn film. The biaxially-drawn film is thermally fixed at 170-210°C, and the thermally fixed biaxially-drawn film is thermally relaxed at 150-190°C so that the ratio (X/Y) of width-directional relaxation rate (X%) to longitudinal relaxation rate (Y%) is 0.6-1.67, and the product (XY) of X and Y is 15-80, whereby a polyester film having a center line average surface roughness Ra of 10-60 nm is produced. <P>COPYRIGHT: (C)2013,JPO&INPIT |
