Biaxially stretched polyester film roll

Abstract

To provide a polyester film roll that: has a very low antimony content; contains little foreign material; has an excellent transparency and heat resistance; is not only resistant to the occurrence of slack in film roll immediately after film production, but also is resistant to the occurrence of slack in film roll with elapsed time even over long-term storage; and exhibits an excellent printability and processability. A film roll provided by winding a biaxially stretched polyester film that has an antimony content in the film of not more than 10 ppm, a phosphorus content of 25-75 ppm, and an arithmetic mean roughness for the film surface of 0.02-0.05 mum, the biaxially stretched polyester film roll being characterized by satisfying the following requirements (1) to (6): (2) the winding length of the film roll is 8,000-80,000 m; (2) the width of the film roll is 500-4,000 mm; (3) in a measurement of the hardness of the surfacemost layer of the film roll at intervals of 50 mm in the film width direction, the average hardness is in the range of 500-700; (4) in the measurement of the hardness of the surfacemost layer of the film roll at intervals of 50 mm in the film width direction, the variation in the hardness is 10%-20%; (5) the film thickness is 5-40 mum; and (6) with regard to the thickness variation in the film width direction at the surface layer of the film roll, the thickness pattern has locations that form depressions and, in the depression having the largest thickness difference (the largest depression), the thickness variation for the largest depression, as calculated from the average film thickness and the largest thickness difference at the largest depression, is not more than 10%.

Description

technical field [0001] The present invention relates to a biaxially stretched polyester film roll excellent in hygienic properties. Specifically, it relates to a roll that does not cause wrinkles after long-term storage after being formed into a film, and does not cause problems in processing steps such as printing and bag making. Biaxially stretched polyester film rolls used for food packaging bags, labels, etc. Background technique [0002] Polyester resins such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), which are thermoplastic resins with excellent heat resistance and mechanical properties, are used in plastic films, electronics, energy, It is used in many fields such as packaging materials and automobiles. Among plastic films, biaxially stretched PET films are widely used in industrial and packaging fields because of their excellent balance between mechanical property strength, heat resistance, dimensional stability, chemical resistance, o...

AI Technical Summary

Problems solved by technology

However, there is no description about the method of reducing foreign matter in the membrane and the desired membrane properties.

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