| 摘要 |
PROBLEM TO BE SOLVED: To provide a biaxially-oriented polyester film useful as a base film, that has little occurrence of foreign substances resulting from a catalyst, and few dropouts, when it is made as a coated type magnetic recording medium. SOLUTION: This film is a biaxially-oriented polyester film for coated-type magnetic recording medium, consisting of polyester constructed with a main recurring unit of ethylene terephthalate. A phosphorous compound and a titanium compound soluble in polyester are contained in the ranges of inequalities expressed by 2≤Ti≤10, 1≤P/Ti≤10, and 5≤Ti+P≤100 [wherein, Ti indicates the concentration (mmol%) of a titanium metallic element and P shows the concentration (mmol%) of phosphorus element], based on the number of mols of a recurring units of polyester. Further, thickness spots in the width direction of the film are 0.8 micrometers of smaller. COPYRIGHT: (C)2004,JPO |
