Parison separation device, blow molding machine, and method for manufacturing blow-molded article

A blow molding machine comprising:

• a die including a through hole;
• a core inserted inside the through hole;
• an extruder configured to extrude a molten resin and thereby supply a parison to a gap between the die and the core;
• a parison separation device configured to cut and separate the parison discharged from the gap, and thereby form a sheet;
• and
• a mold-clamping device configured to form a blow-molded article by using the sheet,
• wherein the parison separation device comprises:
• a cutter with a cutting edge, the cutting edge extending in a one direction and facing upward;
• and
• a block, the cutter being attached to an upper part of the block, inclined surfaces being formed on both sides of the block in a thickness direction of the cutting edge, each of the inclined surfaces including a component that is inclined increasingly downward as it gets closer to one direction side end, and an inclined-and-curved surface part, the inclined-and-curved surface part of being curved and inclined, and
• the parison separation device is disposed on a discharging direction side of a discharging port for discharging and configured to cut the parison discharged from the discharging port.

A method for manufacturing a blow-molded article, comprising the steps of:

• (A) extruding a molten resin so that the molten resin is discharged as a parison from a gap between a die including a through hole and a core inserted inside the through hole, and cutting the discharged parison;
• (B) separating the cut parison and forming it into a sheet;
• (C) performing twin-sheet molding by using the sheet, wherein
• in the step of cutting the parison,
• a parison separation device is disposed below the die and the core, the parison separation device comprising:
• a cutter with a cutting edge, the cutting edge extending in a one direction and facing upward;
• and
• a block, the cutter being attached to an upper part of the block, inclined surfaces being formed on both sides of the block in a thickness direction of the cutting edge, each of the inclined surfaces including a component that is inclined increasingly downward as it gets closer to one direction side end, and an inclined-and-curved surface part, the inclined-and-curved surface part being curved and inclined.