The mixing quality of PVC dry blends has much to do with the feeding steps of hot mixing process. The general feeding sequence is as follows:
1. First start the PVC high speed mixer at low speed mode, and add PVC resin, pigment and stabilizer when the temperature is below 60℃.
2. Then adjust the PVC mixer to high speed mode, and add various modifiers at about 80℃(if use liquid stabilizer can be added in advance).
3. Add lubricant at around 95℃ (it can be added in advance when using liquid stabilizer);
4. Add filler and regrind at 110℃ (it can be added in advance when using liquid stabilizer); keep high speed hot mixing mode until the set temperature reaches required value by the process.
5. After the hot mixing is completed, the PVC dry mixtures are discharged at a low speed into the cold mixing, and the material is discharged when the temperature reaches about 42℃, and the packaging is ready for use.
The packaging and storage of PVC dry mixtures should take place at low moisture ambient. And the hopper dryer is needed if long time storage before the next use.