| 摘要 |
An extruder die head comprises an internal cylindrical mandrel and a shell, which encloses said mandrel concentrically. Between said mandrel and shell an annular channel is formed that empties into the die slit. A polymer melt is fed through a line to the annular channel. To prevent the polymer melt in the area of the start of the annular channel from penetrating into a slit that forms between the mandrel and the shell due to heat expansion, there is between both mandrel and shell a ring with such a coefficient of thermal expansion that when heated up due to the polymer melt said ring seals the slit between the shell and the mandrel.
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