| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a polyester film containing polyethylene naphthalate from which fine foreign matter is highly removed as a main component with high productivity. SOLUTION: The method for manufacturing a polyester film comprises the steps of melting polyester of 2,6-ethylene naphthalate unit of 70 to 100 mol.% of total repeating unit, filtering it, and then melt extruding it in a sheet-like state. In this case, it is filtered by a heat resistant fiber filter having an interstice of a range of 1 to 20μm and a void fraction of a range of 50 to 90%, and then by a filtering unit having at lest one filter having a pore side of converting from an input side of the melt polyester toward a discharge side. |
