| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a polyester film that solves the problems in the conventional technology and has high transparency and wherein the degradation of its mechanical property is suppressed and delamination is hard to occur even after long-term usage under an environment of high temperature and high humidity. <P>SOLUTION: The polyester film for solar cells is formed of a biaxially-oriented film of polyethylene terephthalate, wherein the weight average molecular weight thereof is 44,000-61,000, the concentration of a terminal carboxyl group is 6-29 t Eq, the elongation retention is 50% or greater after aging the film at 85°C and 85% RH for 3,000 hours, the thermal shrinkages in the lengthwise direction and width direction are -0.1 to 1.5% after heating it at 150°C for 30 minutes, the light transmittance is 80% or greater at a wavelength of 550 nm, and the tearing load is 0.4 N or greater. <P>COPYRIGHT: (C)2011,JPO&INPIT |
