BIAXIALLY-ORIENTED POLYETHYLENE TEREPHTHALATE FILM FOR TESTING OPTICAL FILM

摘要

PROBLEM TO BE SOLVED: To provide a biaxially-oriented polyethylene terephthalate film capable of post-processing treatment at high temperature and suitable for high accuracy test of an optical film for large screen applications.SOLUTION: There is provided a biaxially-oriented polyethylene terephthalate film for testing an optical film satisfying following requirements (1) to (4). (1) Heat shrinkage when heated at 150°C for 30 minutes is 2.0% or less in both of a longitudinal direction and a width direction. (2) A difference between maximum and minimum of heat shrinkage in all directions when heated at 150°C for 30 minutes is 0.5% or less. (3) A maximum variation of all direction heat shrinkage per 5° when heated at 150°C for 30 minutes is 500 ppm or less. (4) A variation of an orientation angle in a film width direction is 0.2° to 0.8° per 100 mm.SELECTED DRAWING: None