| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a resin tube by blow molding capable of advantageously manufacturing the tube having a uniform thickness as uniform as possible. SOLUTION: The method for manufacturing a resin tube by blow molding comprises the steps of forming a cylindrical inside resin layer having a plurality of outside protruding strips on an outer peripheral surface, forming a cylindrical outside resin layer having a plurality of inside protruding strips on an inner peripheral surface so that distal end faces of the inside strips are respectively contacted with distal end faces of the corresponding outside strips while blowing gas between opposed surfaces of the inside layer to the outside of the inside layer and a gap extending in an axial direction is provided between opposed surfaces of the inside layer in which the gas is blown, molding a parison having a three-layer structure made of the outside layer, the inside layer and a gas layer formed of the gap provided therebetween, while incorporating the parison in a molding cavity formed between an upper mold and a lower mold oppositely disposed in a vertical direction, and then blowing the gas into the parison, thereby manufacturing the resin tube. |
