| 摘要 |
PURPOSE: To obtain a foldable hollow vessel having an excellent pressure resistance strength by orientation blow molding in a mold having a bellows like cavity. CONSTITUTION: A polyester hollow vessel has a port 1 and a bellows like body 3 is such a manner that the thickness of the body 3 preferably has a range of 70 to 200μm or preferably 90 to 120μm. If the thickness of the body has the range, it has excellent flavor barrier properties, and even if the vessel is repeatedly used and folded, the decrease in the strength of the vessel is small. When the vessel is molded by using the mold having a bellows like cavity by a blow molding method or preferably a biaxial drawing blow molding method, it is desired that the drawing magnification of the body is 10 times or more or preferably 12 to 20 times, and the longitudinal drawing magnification is twice to four times, and the lateral drawing magnification is preferably 2.5 to 6 times. |
