| 摘要 |
PROBLEM TO BE SOLVED: To produce film having releasability, comprising a specific polyethylene naphthalate, excellent in thermal stability, hardly including foreign matter, excellent in flatness and surface smoothness, and useful for carrier film for producing resin sheet, resin coat, ceramic sheet or the like, and protective film for a tacky layer of adhesive tape or the like. SOLUTION: The objective film having releasability is a film made of polyethylene naphthalate obtained mainly from a lower alkyl naphthalenedicarboxylate and ethylene glycol. The polyethylene naphthalate includes an Mg compound, a Ca one, a P one and an Sb one so as for formulas 1.0<=Ca+Mg<2.6, 3.0<=Mg/Ca<=6.0, 2.3<=(Ca+Mg)/P<=7.0 and 0.4<=Sb<=2.0 to be simultaneously met. The surface of the base film has 1-100 nm arithmetical mean deviation of profile (Ra).
|
