| 摘要 |
PURPOSE: To enhance the dimensional stability and mechanical strength of a polyester film by setting the ratio of dynamic loss at specific temp. to a specific range. CONSTITUTION: The ratio of the dynamic loss tanδat 95 deg.C of a polyester film is set to 1.05-15, pref., 1.05-1.4. When polyester is polyethylene-2,6-naphthalate, the dispersion peak of tanδis observed in the vicinity of 95 deg.C and this dispersion peak is considered to be based on the motion of a naphthalene ring and, when the ratio of tank at 95 deg.C is within this range, the motion of molecules is restrained and the dimensional change by heat of the film and the deformation at a time of the reception of long-time stress of the film are hard to generate. |
