| 摘要 |
PROBLEM TO BE SOLVED: To provide a polyester giving a film very suitable for electrical insulation which contains a cyclic trimer in a very small amount enough to keep low the amount of the cyclic trimer extracted from the film by a refrigerant in case that the film is brought into contact with the refrigerant when the film is employed for electrical insulation for an enclosed motor for a refrigerator thereby preventing troubles caused by deposition on various parts of the refrigerator of the trimer resulting in clogging, and is excellent in hydrolysis resistance, heat resistance and mechanical characteristics enough to further lengthen the life of the motor for a refrigerator. SOLUTION: The polyester composition comprises at least 90 mole% of an ethylene terephthalate unit and contains at least one polymerization catalyst metal compound selected among antimony compounds, germanium compounds and titanium compounds, where the amount of the polymerization catalyst metal compound in terms of the metal is at least 0.2 mole/ton and at most 1 mole/ton based on the polyester and the content of an ethylene terephthalate cyclic trimer is less than 0.4 wt.% based on the polyester. |
