| 摘要 |
Large, multi-layer parisons with an inner layer, an intermediate layer, and an outer layer for use in intermittent extrusion blow molding are formed using a die head including a housing, an annular inner conduit having a first resin inlet with a horizontal axis, an intermediate conduit having a second resin inlet with a horizontal axis, and an annular outer conduit having a third resin inlet with a horizontal axis, a closable, tubular extrusion orifice in communication with the inner, intermediate and outer conduits, the first inlet being in a plane above the second inlet and the second inlet being in a plane above the third inlet; and first, second and third reciprocating screw extruders, each extruder including a cylinder with a resin inlet and a resin discharge outlet, a screw rotatable within the cylinder to convey the resin from the resin inlet to the discharge outlet, the screw being axially movable away from the outlet when the screw is rotating, and drive means for moving the screw rapidly toward the outlet to force resin through the die head, the discharge outlet of the first extruder communicating with the first inlet, the discharge outlet of the second extruder communicating with the second inlet, and the discharge outlet of the third extruder communicating with the third inlet.
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