| 摘要 |
PURPOSE:To improve the weatherability, resistance to piercing, glass scattering preventing effect and transparency of film by using a polyethylene naphthalate film which has breaking strength, surface haze and file haze or the sum of surface haze and internal haze of the film, respectively lying within specified ranges. CONSTITUTION:Polyethylene naphthalate film, the sum of the breaking strengths in longitudinal direction and in lateral direction on which is 45kg/mm<2> or more, preferably 50kg/mm<2> or more and more preferably 55kg/mm<2> or more, is used. The above-mentioned film can be obtained by especially stretching in longitudinal direction and in lateral direction by the draw ratios of 300% or more, preferably 350% or more respectively or further stretching in longitudinal and/or lateral directions or the like. In addition; the surface haze of the film is to be 0.3-3% and the film haze which is the sum of the surface haze, and the internal haze of the film is to be 0.5-5% when converted to the thickness of 50mum. The workability of a film, the film haze of which is below 0.5%, deteriorates. On the contrary, a film, the film haze of which exceeds 5%, is poor in the transparency and the visual recognition of an object through said film becomes difficult. |
