PVC Resin SG-5 is used as raw material for extrusion of UPVC pipe. PVC heat stabilizer, PVC lubricant, filler and pigments are also needed. Abovementioned materials shall be blended in a certain proportion as formula. If single-screw extruder is used for extrusion of UPVC pipe, PVC masterbatch shall be added into the extruder. If double-screw extruder is used for extrusion of UPVC pipe, PVC compound powder can be used directly for extrusion of UPVC pipe. General technological process of UPVC pipe is listed as below:-
In addition, it can be different from abovementioned process flow as per real production situation, that is, PVC compound powder can be directly used for UPVC pipe making rather than using PVC granule, but two points shall be paid attention to:-
1. It’s better to use double-screw extruder for UPVC pipe making if PVC compound powder is added into the extruder. Compare with PVC granule, blending shearing plasticization process is not needed if PVC compound powder is used. Therefore, double-screw extruder will enhance the effect of blending shearing plasticization process for a better achievement of expected effect.
2. Because PVC granule is more dense than PVC compound powder, thus having relatively low heat conduction. Processing temperature for PVC compound powder shall be 10oC lower that that for PVC granule.