Extruder maker American Maplan Corp. has developed screws designed to run modified PVC (MPVC) and chlorinated PVC (CPVC).
MPVC pipe has improved toughness and impact strength needed for pipe and fittings for water distribution, air distribution and mining applications. The properties are comparable to unplasticized PVC, according to Maplan, based in
The screw has a special flight geometry that provides optimum plastification without sacrificing output rate or an increase in melt temperature because of shear. Extruding MPVC compound presents processing issues because of the need for additional energy input for proper plastification.
Maplan said CPVC compounds can present challenges because of their thermal instability. The company's CPVC screw provides a typical reduction of melt temperature up to 15-20°F, while giving superior plastification. A reduced melt temperature significantly extends the reaction or decomposition time.
The screw also can double the time between purges and shutdowns for cleaning.
Tel. 620-798-2304, fax 620-241-2142, e-mail [email protected].