| 摘要 |
PURPOSE:To obtain the titled film improved in abrasion resistance and running stability, by using a composition obtained by adding specified non-incorporated particles depositing in a reaction system and a surface-roughening agent to a polymer based on a polyester. CONSTITUTION:A composition is obtained by adding non-incorporated particles depositing in a reaction system (A), average particle diameter of 0.3-3mu, containing at least 1 part of at least one element selected from among 0.005-0.025wt% Li, 0.01-0.04wt% Ca, 0.02-0.05wt% P and 0.02-0.04wt% Sb and 0.005-0.2wt% inorganic inert incorporated particles (B) (e.g., TiO2) of an average particle diameter of 0.1-3mu as a surface-roughening agent to a polyester based on an aromatic dibasic acid ester containing at least 80mol%, based on the main repeating units, ethylene terephthalate units. This composition is formed into a sheet, and this sheet is biaxially oriented to obtain a biaxially oriented polyester film for magnetic tapes on at least either surface of which fine protrusions of a parameter of distribution (PD value) >=0.5 are formed. |
