Rigid PVC is a kind of plastic product with little or no plasticizer. This kind of plastic product with PVC resin and stabilizer as the main body will inevitably cause the poor fluidity of rigid PVC plastics. In the process of extrusion, the plastic must be in the viscous flow state. Therefore, in order to ensure a certain degree of fluidity of plastics, the processing temperature must be increased. However, the increase of processing temperature is limited. If the decomposition temperature is exceeded, the normal operation will be destroyed. Therefore, the processing temperature and decomposition temperature of rigid PVC must be considered in the formulation design. Accurate temperature control of the extruder is also very necessary.
For the pipe fitting injection process, it is always better to use rigid PVC compounding pellets.
Technical Specifications of Extruder
|Screw Diameter (mm)||51.4||120||62.4||150||71||180||93||250|
|Screw Speed (rpm)||500||90||500||90||500||90||500||90|
|Motor Power (kw)||75||37||132||55||200||75||550||132|
The first stage is a co-rotating twin screw extruder with a modular structure for screws and barrels. You can change the screw configuration easily for a different formula. Due to the high screw speed (about 300-500rpm), it will get better dispersion and more output, but a low melt temperature.
The second stage is a single screw extruder. It is used to cool down the melt material from the twin screw extruder and extrude it for pelletizing.
Compared with soft PVC, the extruder of rigid PVC needs more motor power.