| 摘要 |
<p>The invention provides a TFE polymer capable of providing stretched materials excellent in membrane homogeneity. The present invention is related to a tetrafluoroethylene polymer having stretchability and non-melt-processability and having a standard specific gravity of 2.140 to 2.165, wherein, with regard to the heat-of-fusion curve obtained by subjecting the tetrafluoroethylene polymer in the form of an unbaked polymer to be measured having no history of being heated to a temperature of 300°C or higher to differential scanning calorimetry at a programming rate of 2°C/minute, the ratio between the amount of heat, S 2 mJ/mg, absorbed within the temperature range of from the temperature T 0 °C, which is lower by 2.5°C than the temperature T p °C corresponding to the minimum point on the curve (provided that 340 ‰¤ T p ‰¤ 345), up to 350°C, and the amount of heat, S 1 mJ/mg, absorbed within the temperature range of from 320°C up to the above-mentioned T 0 °C, namely the ratio [S 2 /S 1 ], is not lower than 0.90.</p> |
