| 摘要 |
PROBLEM TO BE SOLVED: To provide a white polyester film excellent in film forming properties, and light weight, as well as whiteness, create resistance upon folding, and printing properties. SOLUTION: This white polyester film is composed of a polyester with a melting point Tm, containing a thermoplastic resin therein that is incompatible with the polyester, and containing fine gas bubbles inside. The melt viscosity of the thermoplastic resin is 2×10<2> -1×10<3> poise at a melting temperature (Tm+20 to Tm+30 deg.C), and a shear rate of 200 s<-1> .
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