| 摘要 |
An annular co-extrusion die for extruding multi-layer tubular plastic film has a lower part and an upper part. The lower part has concentric radially spaced lower die members of different diameters forming at least two lower concentric radially spaced annular passages communicating with a common annular passage for separately feeding different plastic materials along the lower annular passages to the common annular passage for extrusion therefrom. The upper part has upper annular die members located above the lower die members and stacked one upon another. The upper annular die members forms at least one upper annular passage for separately feeding different plastic materials along each upper annular passage to the common annular passage for extrusion therefrom with the plastic materials from the lower annular passages as a multi-layer tubular plastic film.
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