| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a polyester film capable of exhibiting excellent electromagnetic conversion characteristics and error rate characteristics even when used for a coat-type magnetic recording tape.SOLUTION: The provided laminate polyester film is a base film used for a coat-type magnetic recording tape and consisting of at least two layers, namely a layer A forming the surface of the side where a magnetic layer is formed and a layer B forming the surface of the side where the magnetic layer is not formed, wherein the layer A includes 0.001-0.19 mass% of particles having an average diameter of 0.06-0.29μm and a relative diameter standard deviation of 20% or below in a state where the textural index of the surface of the layer A is being confined to a range of 80-99.99%, wherein the layer B includes 0.03-0.9 mass% of particles having an average diameter identical to that of the layer A and a relative diameter standard deviation of 20% or below in a state where the content of the included particles is at least 1.5 times higher than that of the layer A, wherein the density of aggregated protrusions of five or more particles of the layer A is 3 protrusions/9 cmor less, and wherein the density of aggregated protrusions of five or more particles of the layer B is 10 protrusions/9 cmor less.</p> |
