| 摘要 |
<p>PURPOSE: A polyester film, its preparation method, a magnetic recording medium using the film and a digital recording cassette tape using the magnetic recording medium are provided, to improve the electron conversion property of a magnetic recording medium by improving the surface characteristic of a polyester film. CONSTITUTION: The polyester film comprises a polyester and a thermoplastic resin other than the polyester, wherein the coarse projection H1(the number of projections with a height of 0.28 micrometers) of the at least one surface and the coarse projection H2(the number of projections with a height of 0.56 micrometers) of the same surface satisfy the following conditions: 0<=H1<=100 and 0<=H2<=10. Preferably the polyester film comprises further a laminated layer on at least one side of the based layer comprising a polyester and a thermoplastic resin other than the polyester. Preferably the polyester is a polyester containing an ethylene terephthalate unit or an ethylene(2,6-naphthalenedicarboxylate) unit as a main component; and the thermoplastic resin has a glass transition temperature higher than that of the polyester.</p> |
