POLYESTER FILM AND GAS-BARRIER POLYESTER FILM

摘要

A polyester film which has impact resistance and flexing pinhole resistance and comes to have excellent gas-barrier properties upon metal or metal oxide deposition thereon, while retaining the low hygroscopicity, dimensional stability, flatness, and transparency which are characteristics of polyester films. The polyester film is made of a mixture comprising 70 to 97 wt.% polyester A comprising ethylene terephthalate as the main repeating units and 3 to 30 wt.% polyester B comprising butylene terephthalate as the main repeating units, and has a melting point of 245 to 270°C. Alternatively, it comprises a polyester resin comprising 90 to 60 wt.% ethylene terephthalate units, 10 to 40 wt.% butylene terephthalate units, and 0.1 to 5 wt.% polyoxyalkylene glycol units. This polyester film is suitable for use in applications such as food packaging.