Teijin Limited

Hiroshi Kusume

Koji Furuya

Shinya Watanabe

Makoto Handa

Akira Kameoka

A polyester film which is excellent in uniform light diffusibility, heat-resistant dimensional stability and luminance and suitable as a substrate of a light-diffusing plate of a liquid crystal display device. The film comprises a polyester containing polyethylene-2,6-naphthalene dicarboxylate as a main component and has a heat shrinkage in two directions perpendicular to each other in the surface of the film of not higher than 0.3% when heat-treated at 105&#xb0; C. for 30 minutes, a dimensional change rate in two directions perpendicular to each other in the surface of the film under a stress of 0.37 MPa within a temperature range of 30 to 150&#xb0; C. of not higher than 1.0%, a density of not lower than 1.350 g/cm, a total light transmittance of not lower than 87%, a haze value of lower than 1.5% and a thickness of 50 to 150 &#x3bc;m.

Biaxially oriented polyester film for light-diffusing plate and light-diffusing plate

A film which is a biaxially oriented film comprising polyethylene-2,6-naphthalenedicaboxylate as a principal component, having a thermal strain ratio RMD (150) in the machine direction of the film at a temperature of 150&#xb0; C. is &#x2212;1.5%&#x2266;RMD (150)&#x2266;0.0% when the thermal strain ratio RMD (T) in the machine direction of the film at a temperature T&#xb0; C. based on the length LMD (t) in the machine direction (MD) of the film at a temperature t&#xb0; C. is defined by()={[()&#x2212;(35)]/(35)}&#xd7;100(%),excellent in insulation characteristics without lowering processing characteristics, especially the characteristics during hot-pressing and suitable as a dielectric for capacitors.

Polyester film for capacitors

A biaxially oriented polyester film which has excellent productivity while ensuring a transferred image having excellent shape reproducibility and gradation and is particularly suitable for use as a base film for a heat-sensitive transfer ribbon. This film is formed by simultaneous biaxial orientation and contains 0.1 to 2 wt % of inert inorganic particles having an average particle diameter of 0.5 to 5 &mgr;m. This biaxially oriented polyester film has a value of 0.028 or less obtained by dividing the heat shrinkage factor (HS) (%) in a longitudinal direction at 200&deg; C. by the F-5 value (N/mm ) (F5) in the longitudinal direction measured at normal temperature (about 23&deg; C.) of the film.

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Sagamihara, Japan

Hiroshi Kusume