| 摘要 |
PROBLEM TO BE SOLVED: To provide a polyester film for magnetic recording medium which can make flatness, blocking resistance and abrasion resistance compatible with each other. SOLUTION: This polyester film for magnetic recording medium is a composite polyester film having on at least one of its surfaces a coat layer A comprising a binder (A1), inert fine grains (A2), a surfactant (A3) and a stylene polymer or copolymer (A4) having sulfonic base. Characteristically, the content of the stylene polymer or copolymer (A4) having the sulfonic base in the coat layer A is 1 to 40 wt.%, and the Ra (root mean square roughness) by AMF of the outer surface of the coat layer A is 0.1 nm or larger but less than 3 nm, and its Rz (ten-point mean roughness) is 5 nm or larger but 40 nm or smaller.
|
