| 摘要 |
A polyester stretch film having good tear property and good twistability, which is useful as a packaging film or a film for tape, as well as for stick packaging, PTP packaging, drug bag, folding packaging, and lid material is provided without losing heat resistance, cold resistance, moisture-proof properties, transparency, aroma retention and the like. This polyester resin film is produced by a method that includes mixing not less than two kinds of polyester resin starting materials having different melting points and extruding the mixture. The respective starting materials are cast in different extruders, melted, supplied to one mixer in a molten state, mixed and extruded to give a sheet, and the sheet is stretched at least in the monoaxial direction and heat-treated at a temperature of not lower than 3° C. lower than the melting point of the resin starting material having the lowest melting point.
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