| 摘要 |
PURPOSE:To obtain a white polyester film substrate improved in whiteness and reduced in whiteness deterioration by making the film have a specific spectral reflectance. CONSTITUTION:The title film has a spectral reflectance in which the reflectance at 320nm is 30% or lower and that at 440nm is 100% or higher. The film is obtained, for example, by mixing 97.79-88.8 pts.wt. polyester with 2-10 pts.wt. TiO2 as a white pigment, 0.2-1.0 pts.wt. ultraviolet absorber, and 0.01-0.20 pts.wt. fluorescent brightener. It can retain sufficient whiteness over long when used for a label, poster, recording paper, packaging material, etc. |
