| 摘要 |
PURPOSE:To obtain a biaxially oriented polyester film which is flat and excels in lubricity, chipping resistance, etc., by dispersing two kinds of spherical silica particles each of which is specified in the average particle diameter, particle diameter ratio and amount of addition in a polyester. CONSTITUTION:First spherical silica particles having an average particle diameter of 0.6-3mum and a particle diameter ratio (major diameter/minor diameter) of 1-1.2 and second spherical silica particles having an average particle diameter of 0.7-3.1mum and a particle diameter ratio of 1-1.2 are prepared. 0.001-2.5wt.% first spherical silica particles and 0.001-2wt.% second spherical silica particles are dispersed in a polyester (e.g., polyethylene terephthalate). This polyester is formed into a film, which is biaxially oriented to obtain a biaxially oriented polyester film. This film can be suitably used as a base film for videotapes, computer tapes, etc. |
