POLYESTER FILM FOR MAGNETIC RECORDING MEDIUM AND MAGNETIC RECORDING TAPE

摘要

PROBLEM TO BE SOLVED: To provide a polyester film for a base film suitable for forming a digital video tape excellent in electromagnetic transducing characteristics and nearly free from DO, wherein a cooling can not become dirty when the film is used to manufacture a magnetic tape even in high vapor deposition speed. SOLUTION: The polyester film for a magnetic recording medium consists of a laminated film consisting of a layer A and a layer B and a coating layer formed on the surface thereof. A surface A on the side of the layer A has 2-4 nm SRa value and 10-40 nm SRz value. Fine particle for forming surface projections on a surface B on the side of the layer B are contained in the layer B and the fine particles have 50-500 nm average particle size. The layer B has 0.01-1.0 wt.% fine particle content and the coating layer applied and formed on the side of the layer B has 1-10 nm thickness. A ferromagnetic metallic thin film layer is provided on the outer side of the surface A to form the polyester film used as a magnetic recording medium.