| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a polyester film which is capable of exhibiting an excellent electromagnetic conversion characteristic even used for the base film of a data storage having a storage capacity of 0.8 TB or more and a magnetic recording medium substrate. <P>SOLUTION: A polyester film is a base film used for the data storage having a storage capacity of 0.8 TB or more, with a surface on the side forming a magnetic layer having open defects measured by interference of light with a wavelength of 260 nm, the number of the open defects having major diameter of 10μm or more being 100 pieces/100 cm<SP POS="POST">2</SP>or less. Besides, a magnetic recording medium substrate is characteristically provided with a layer consisting of a metal or a metal based inorganic compound (layer M) laid at least on the side forming the magnetic layer of the base film. <P>COPYRIGHT: (C)2012,JPO&INPIT</p> |
