| 摘要 |
PURPOSE: To provide a photographic substrate having low haze, high transparency, improved smoothness and excellent heat-resistant curling characteristics and containing ethylene naphthalate as the main structural unit. CONSTITUTION: (1) This substrate is a film obtd. by biaxially stretching a polyester containing ethylene naphthalate as the main structural unit and having >=100 deg.C glass transition temp. The film contains pulverized silica having 0.1 to 1.0μm average particle size. Further, the film is annealed at temp. lower than the glass transition temp. of the polyester but not lower by >=20 deg.C than the glass transition temp. for 1 to 180 hours. (2) The pulverized silica in the polyester film has 0.01 to 5μm particle size and the proportion of particles having >=1μm particle size is <=20% of the whole particles. |
