Teijin Dupont Films Japan Limited

Naoko Matsumura

Atsushi Oyamatsu

Shinichiro Okada

In a laminated polyester film for solar cell backsheets, which includes a surface layer (A) and a substrate layer (B), the surface layer (A) is made of a polyester composition including 10 to 30 wt % of rutile-type titanium dioxide particles and 70 to 90 wt % of a polyester, the substrate layer (B) is made of a polyester composition including 0.1 to 4 wt % of rutile-type titanium dioxide particles and 96 to 99.9 wt % of a polyester, the substrate layer (B) has a thickness of 70% to 97% of the total film thickness, the weight average molecular weight and COOH end group concentration of polyester in the laminated film are 47,000 to 65,000 and 6 to 25 eq/ton, respectively, and the average content of rutile-type titanium dioxide particles in all layers of the laminated film is 3 to 8 wt %. As a result, a laminated polyester film for solar cell backsheets, which has excellent weatherability and hydrolysis resistance and is capable of maintaining strength over a long period of time, is provided.

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Gifu, Japan

Naoko Matsumura