| 摘要 |
PURPOSE:To obtain the titled film suitable for PET bottle labels for cooling beverages, outstanding in solvent resistance for inks, by drawing a PET film with its surface temperature controlled so as to give each specific thickness variation, static coefficient of friction, birefringence and shrinkage. CONSTITUTION:A polyester made by polymerization between (A) a dicarboxylic acid component such as terephthalic acid and (B) e.g., ethylene glycol is subjected to melt extrusion followed by quenching. The resultant film is heated so that its surface temperature fall pref. between the glass transition temperature of said polyester (T) and (T+40) deg.C followed by unidirectional drawing by a factor of 2-5, thus obtaining the objective film having such characteristics as follows: 1, thickness variation for longitudinal and lateral directions... <=30%, 2, static coefficient of friction... <=1.2, 3, birefringence... >=0.040, 4, shrinkage in 100 deg.C air oven either in the longitudinal or lateral direction >=40% in the other direction... <=20%.
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