BIAXIALLY ORIENTED LAMINATED POLYESTER FILM AND METHOD FOR MANUFACTURING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a biaxially oriented laminated polyester film characterized in that a dimensional change ratio and a rise in the coefficient of friction are reduced after long-term use under constant load at a high temperature and suitable for use as a high capacity magnetic tape. SOLUTION: The biaxially oriented laminated polyester film is obtained by providing a lamination part comprising an organic polymer or inorganic matter on at least one surface of a biaxially oriented polyester film and the elastic modulus in the longitudinal direction and/or lateral direction of this film is 7.0 GPa or more, the heat shrinkage factor thereof at 100 deg.C measured in the same direction is 0.50% or less and the creep compliance thereof after the elapse of 30 min under a load condition of 28 MPa at 50 deg.C measured in the same direction is 0.05-0.30 GPa-1.