Co-extruding polymers with differing processing temperatures

摘要

The apparatus for coextruding polymers whose processing temperatures vary, consists of two or more extruders connected to a coextrusion head that is provided with heating, cooling and insulating zones. The coextrusion head (4) is provided with low temperature (11) and high temperature (12) flow channels that accept polymer melt flows from first (1) and second (2) extruders. Flow from these channels is conducted to a die/die holder combination (3) attached to the coextrusion head. In the die, the flows are combined and shaped as a coextrusion of desired form (6). The separate polymer flows (11,12) are combined only at the die front plate (13). Coextrusion head (4) consists of a manifold (10) that includes zones for cooling (20,21), heating (30,31) and insulating (40). The cooling zones are provided as semi-arcuate channels on either side of low temperature flow channel (11). The heating zones are similarly provided on either side of high temperature flow channel (12). The insulating zone is provided between adjacent cooling (20) and heating (30) channels. Cooling (22,23), heating (32,33) and insulating (41) zones are similarly provided in die/die holder (3).