To provide a base film suitable for forming a digital video tape excel lent in electromagnetic transducing characteristics, less in drop-out over its entire length from the winding core part to the outer layer part of a product.
The polyester film for magnetic recording medium formed by layering a polyester layer A and a polyester layer B is characterized in that the surface of the layer A side has 2-4 nm centerline average surface roughness (SRa value) and 10-40 nm ten-point average surface roughness (SRz value) and the layer B contains fine particles α having ≥50 nm and <250 nm average particle size and fine particles β having ≥250 nm and <500 nm average particle size and fine particles α content and fine particles β content in the layer B are 0.1-1.0 wt.% and 0.01-0.1 wt.%, respectively. A magnetic recording tape is formed by providing a ferromagnetic metal thin film on the surface of the layer A side of the polyester film.
OKAMOTO KATSUYA
CHIKUGI TOSHIHIRO
MORIMOTO TSUTOMU
