| 摘要 |
PURPOSE:To provide the moisture and heat resistance superior to the moisture and heat resistance of a triacetate film to the titled film by forming the film having >=0.08 difference in refractive index between transverse and longitudinal directions, within 5 deg. angle of inclination of the orienting axis with respect to the longitudinal direction and >=80% visible ray transmittance. CONSTITUTION:Polyethylene terephthalate is formed into a film in an extrusion film forming stage and is stretched 3.5-4.5 times longitudinally thereby obtaining a uniaxially oriented polyester film for a liquid crystal display plate having >=0.08 difference between the refractive index in the longitudinal direction and the refractive index in the transverse direction, within 5 deg. angle of inclination of the orienting axis with respect to the longitudinal direction, >=80% visible light transmittance and <=1% thermal shrinkage rate at 150 deg.C and 30min. The resulting polyester film is lighter and more hardly breakable than previously used glass and is superior to a triacetate film formed by a casting method in moisture and heat resistance. |
