Extruder for PVC Compounding

TSC Tandem Line for Compounding and Air Cooling Hot Face Pelletizing

Combine the high speed and extensive mixing of twin screw processing and the low speed, low temperature, and low shear of single screw processing

Rigid PVC product mostly made by conical twin screw plastic extruder machine line. Soft PVC product mostly made by co-rotating twin screw extruder machine line. Here we just introduce co-rotating twin screw extruder extrusion process.

Machine Flowchart: 

Hot and cold mixing unit — co-rotating twin screw extruder — Single screw extruder — Air cooling hot cutting system — Pellets sifting and packing.

According to the formulation, put the PVC resin, plasticizer, CaCO3, stabilizer and other auxiliaries into hot mixer mixing. After 6-10 mins discharge into the cold mixer (6-10 mins) for premixing. PVC compounding must use the cold mixer to prevent material stick together after the hot mixer.

Feeding the mixture material into first stage twin screw PVC pettizing line through the screw loader and metering twin screw feeding hopper.

The mixture material finished plasticizing, mixing and dispersing evenly in the PVC compounding extruder with around 155°C-165°C. And then the melting PVC compounding (150°C-160°C) following into the second single screw extruder directly. The melting PVC compounding finished extruding and pelletizing by the single screw extruder with low speed, high pressure and cooling state. And the extrusion temperature has dropped to 110°C-120°C. At this time the air cooling die-face hot cutting system can be easy working and make sure the material will not stick to the cutting blade. 

(Ps: 1.Due to the high rotate speed of twin screw extruder, PVC compounding pettizing line normally cannot be direct pelletizing. The pressure of die-head will be very high. 2.Long time at high temperature, PVC easily carbonized)

After pelletizing, the granules temperature can be dropped to 35°C-40°C after two stages cyclone cooling system. Then after the wind-cooled vibrating sieve, the particle temperature drops below room temperature to be sent to the final product silo for packaging.

Soft PVC, 30% < plasticizer < 70%. Using for making PVC sealing strips, hoses, cables, film, artificial leather, soles, toys etc.