Biaxially Oriented Polyester Film
Patent #: 6,902,819
Inventor(s): Sangil Kim and Changju Lee
Company: SKC Limited
A biaxially oriented polyester film prepared by biaxially drawing a polyester sheet was patented. The film has a glass transition temperature (Tg) of 60° C. or higher, in the longitudinal and transverse directions, wherein the biaxially oriented film has a specific gravity of 1.38 or less and a dead-fold retainability of at least 60% defined as below: Dead-fold retainability (%)=(180?ı)?100/180 wherein ı is an angle formed when a polyester film sheet is folded under a pressure of 30 psi for three seconds at room temperature and the folded sheet is kept at a vertical position for one hour.
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