| 摘要 |
PURPOSE:To improve the forming efficiency of a thick resin tube by compression-forming a sheet-like material of polyvinyl alcohol at 95 to 150 deg.C using a porous molding die. CONSTITUTION:The top force 1 and the bottom force 2 of a compression- forming die have a cavity forming part each 3, 4, and the forming part 3, 4 is composed of a porous structure having continuous bubble-type micropores. The diameter of the micropore is 5 to 20mum. A suction orifice 11 provided on the bottom force 2 is connected to an exhaust passage 10 from the die. A sheet-like material of polyvinyl alcohol resin is deposited on the upper and lower areas of a mandrel in the forming cavity, and then is compression-formed into a tube. The air is exhausted from the porous surface during compression- forming, so that no bubbling phenomenon occurs in the tube. Thus it is possible to form even a thick tube having high transparency at high efficiency. |
