JPS6221609B

PURPOSE:Title molded article that is formed by melt closing the one end of polyester open tube into a dome with specifically shaped shoulder, thus preventing the crack formation on the surface and giving beautiful appearance. CONSTITUTION:When an open tube of polyester containing polyethylene terephthalate as major recurring structural units is heated up to the molding temperature on both ends to form the one end 1 into a dome with specifically shaped shoulder by fusing between mold 2 and mandrel 3 and the other end into the neck with desired shape, a shoulder satisfying equations : 0.7>=d 1/d 0>=5, 2>=h/a>=1 (d0 is the outer diameter of tube, d1 is the diameter of the shoulder end, h is height of the shoulder, a is the wall thickness of the tube) is formed at the part of the bottom. Thereby, the crack formation is prevented on the surface.