| 摘要 |
PURPOSE:To enhance productivity by improving an orientation property, by forming a protrusion and a concavity around said protrusion to the surface of an aromatic polyester film containing a specific amount of poly(alkylene glycol). CONSTITUTION:As poly(alkylene glycol), poly(ethylene glycol) is perfferred and added to and contained in aromatic polyester with a M.W. of 100-10,000 in a ratio of 2-3wt%. By biaxially orienting an unoriented film of aromatic polyester, a protrusion 21 containing a particle and a concavity 24 formed around said protrusion 21 are generated to the obtained film 23. In order to hold running property as a magnetic tape, the size of the concavity requires a long diameter of 4mum or more and 100/mm.<2> or more are required in the numbers of uneven units. |
