Polypropylene, along with any pigment or
stabilizers the customer might add, is passed
through an extruder having at least four barrel
temperature control zones, a screen pack,
breaker plate, adaptor, and die. Good
temperature control in each of these areas is
required. For general extrusion, the
temperature range from feed throat to front is
390- 450 °F, with the adaptor and die at the
same temperature as the front barrel zone.
Cast film, fibers, and yarns require higher
temperatures; the rear at 430-490°F and the
front, adaptor, and die at 490°F. These
temperatures should be considered only as
guidelines and will vary with individual
processes. Reverse profiles have been used
where more mixing is required