Polyester film for solar cells

摘要

The invention provides a polyester film suitable for a back sheet for solar cells, which requires a high reflectance not only in the visible light region but also in the near-infrared region, and also requires a low reflection directivity. The polyester film is a cavity-containing polyester film having an average reflectance of 70-95% in a wavelength range of 400-1200 nm and an average transmittance of 5-30% in a wavelength range of 700-1200 nm.

主权项

1. A polyester film for solar cells comprising a cavity-containing polyester film having:
an average reflectance of 70% or greater and 95% or less in a wavelength range of from 400 to 1200 nm; and an average transmittance of 5% or greater and 30% or less in a wavelength range of from 700 to 1200 nm; wherein the cavity-containing polyester film comprises (a) a polyester resin, (b) an incompatible thermoplastic resin, which is incompatible with the polyester resin, and (c) a dispersion thermoplastic resin, which is incompatible with both the polyester resin and the incompatible thermoplastic resin; the incompatible thermoplastic resin is present in 4 to 8 parts relative to 100 parts by mass of the polyester resin; and the dispersion thermoplastic resin is present in 10 to 50 parts relative to 100 parts by mass of the incompatible thermoplastic resin.