| 摘要 |
A method of injection-molding three-layer moldings, especially bottle blanks, having inner and outer layers of a "material A" and of a "material B". Material B can be a material that acts as a barrier against the gases O2, CO2, and SO2, and against water vapor (H2O). The method employs a device that comprises at least one mold and at least one flat hot runner. The mold has several cavities and the hot runner has the same number of dies. Material A is supplied to the cavities (1.1) through an annular gap between the inner (2.1) and the outer (2.2) component of each die. Material B is forced into the cavities through a hollow needle (3) that extends through the center of the inner die component by a piston (4) that is integrated into the die and cannot rotate. The needle has a port (6) that opens into it at a right angle and remains open as long as the needle remains advanced, in a closing position, and that is blocked when the needle is retracted. A reservoir (3.3) constituted by the hollow inside the needle is charged through the port while the needle is in its closing position.
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