| 摘要 |
PURPOSE:To obtain a biaxially stretched polyester film for forming having excellent formability, thickness evenness and heat resistance from a polyester film having specific physical properties. CONSTITUTION:In polyester constituting a film having characteristics represented by formula [wherein Gs(60 deg.) is the glossiness (%) of a film, X100 is a fine crystal line (A) measured by X-ray diffraction, n is an average refractive index and DELTAP is a degree of surface orientation], the ratio of polyethylene terephthalate is 50mol.% or more, further pref., 70mol.% or more. When the ratio of polyethylene terephthalate is below 50mol.%, no pref. effect is obtained because the strength and heat resistance of a polyester film are lowered. Further, by containing an aliphatic dicarboxylic acid component as an acid component pref. in a ratio of 1 - 20mol.%, more pref. in a ratio of 1 - 10mol.%, the moldability, heat resistance and thickness evenness of the film can be enhanced. |
