| 摘要 |
PROBLEM TO BE SOLVED: To provide a polyethylene terephthalate composition excellent in hydrolysis resistance and suitable for a front sheet of a solar cell.SOLUTION: There is provided a polyethylene terephthalate composition including ≥1.0 mol/ton and ≤3.0 mol/ton of an alkali metal phosphate compound in terms of an alkali metal element, having a diethylene glycol content of ≥1.0 wt.% and ≤1.5 wt.% and containing ≥1.5 mol/ton and ≤5.0 mol/ton of a phosphorus element, wherein white foreign matter of ≥50 μm including a phosphorus element and an alkali metal element is ≤1 ppm by a volume fraction, and the increment of carboxylic acid terminal groups when the composition is subjected to wet-thermal treatment (for 4 hours at 155°C under a 100% RH atmosphere) (&Dgr;COOH) is ≤50 eq/ton. |
