| 摘要 |
PURPOSE:To obtain the title film of excellent abrasion resistance, containing specified particles. CONSTITUTION:1-15wt.%, based on particles, dispersant such as triethylammonium phosphate is added to a slurry obtained by adding particles of an average particle diameter of 0.05-2.0mum and a Mohs' hardness of 7-10 (e.g., particles of TiN) to ethylene glycol and boiling the obtained mixture for 12-48hr. The resulting ethylene glycol and dimethyl terephthalate are subjected to transesterification and subsequent polycondensation to obtain a polyester of an intrinsic viscosity of 0.60-0.93. An unoriented film obtained by melt-extruding this polyester is stretched in the machine direction at a stretch ratio of 3.0-4.0 and a temperature from the glass transition point of the polymer to its cold crystallization temperature, stretched in the crosswise direction at a stretch ratio of 3.2-4.5 and a temperature form the glass transition temperature plus 10 deg.C to the cold crystallization temperature plus 10 deg.C and heat-treated at 180-250 deg.C for 0.5-60sec to obtain a biaxially oriented polyester film of a film skin thickness of 100-300Angstrom as measured with a secondary ion mass spectrograph and a surface protrusion peak of 0.02-0.50. |
