| 摘要 |
PROBLEM TO BE SOLVED: To provide a biaxially oriented multi-layer laminated polyester film which exhibits dimensional stability to temperature change, limited elongation under the imposition of a load when exposed to high temperature and the compatibility between surface characteristics and takeup properties. SOLUTION: This biaxially oriented multi-layer laminated polyester film is of such a laminated structure that a total of not less than 11 layers consisting of a film layer (A) of an aromatic polyester (A) and a film layer (B) of an aromatic polyester (B), are alternately laminated. Also, a magnetic recording medium using this film is provided. In addition, the ratio of a 6,6'-(alkylene dioxy) di-2-naphthoic acid component to the total acid component, is less than 5 mol% for the aromatic polyester (A) and not less than 5 mol% to less than 80 mol% for the aromatic polyester (B). Further, one surface roughness (RaX) of the biaxially oriented multi-layer laminated polyester film falls within the range of 0.5 to 5 nm, and the other surface roughness (RaY) is larger than PaX by not less than 1 nm and not more than 10 nm. COPYRIGHT: (C)2010,JPO&INPIT |
