Biaxially-stretched polyester film, laminate and packaging bag

Abstract

To provide a biaxially-stretched polyester film that can be used as a base film for vapor deposition, has excellent barrier properties, dimensional stability, processability, bag breakage resistance, and chemical resistance, and has less transfer of an extract to contents after retorting. A biaxially-stretched polyester film having features (a), (b), (c), and (d) below and having a thickness of 10 to 30 μm: (a) the biaxially-stretched polyester film is formed from a polyester resin composition containing a polybutylene terephthalate resin (A) in a range of 60% by mass or more; (b) a thermal shrinkage of the biaxially-stretched polyester film at 150° C. for 30 minutes is −2 to +2%; (c) thickness accuracy of the biaxially-stretched polyester film is 1 to 20%; and (d) a total amount of 1,4-butanediol and tetrahydrofuran volatilized during heating at a temperature of 135° C. for 60 minutes is not more than 2000 ppb.

Dependencies are inferred from the claim text.