| 摘要 |
<p>A biaxially stretched film and a method for the manufacture thereof, containing at least 90 mol % of ethylene-tetrafluoroethylene copolymer, having a value of crystallization property, DELTA T, expressed by the equation DELTA T=Tm-Tc wherein Tm (melting point) stands for the peak melting temperature ( DEG C.) found when a sample is heated at a temperature increase rate of 20 DEG C./minute using differential scanning calorimeter (DSC), and Tc (crystallizing temperature during fall of temperature) stands for the peak crystallizing temperature ( DEG C.) found when the sample is cooled at a temperature decrease rate of 80 DEG C./minute from the melting point plus 20 DEG C. using said DSC, of not less than 15 DEG C. and not more than 60 DEG C., prepared by a method comprising heating a thermoplastic resin containing at least 90 mol % of ethylene-tetrafluoroethylene copolymer to form a molten resin, extruding the molten resin through a die, and cooling the extruded molten resin at a cooling speed of at least 70 DEG C./second in the range of the melting point minus 10 DEG C. to the melting point minus 100 DEG C. to thereby form a film while simultaneously biaxially stretching said film to at least two times the original size in each of the longitudinal and lateral directions.</p> |
