Production Process of PVC Compounding

PVC compounding cable material is a general term for cable materials made of polyvinylchloride (PVC). As a traditional cable material, it still holds the most important market share in the Chinese domestic market. Because its processing is relatively simpler than other cable materials, the market share is relatively big.

Production Process

The raw materials plus various additives are prepared in a certain proportion and added into mixer---screw loader---twin screw metering feeder---twin screw extruder---connector---single screw extruder---hydraulic plate type screen changer---air-cooled die face hot-cut granulator---first stage cyclone separator---second stage cyclone separator---air-cooled vibrating screen---product silo.

Preparations

Sieving the stabilizer, filler, and coloring agent with 80 mesh screens respectively, add plasticizer and grind them with a three-roll grinding machine or colloid grinder, and then weigh. After the plasticizer is evenly mixed, preheat at 90°C for later use.

Mixer

Put in PVC resin, then add plasticizer and stir for a while. After the resin absorbs the plasticizer, add a stabilizer. The temperature of the material is raised to about 90°C by frictional heat and then add filler and coloring agent. When the temperature of the material rises to 110°C, the material is discharged into the cooling mixer to cool down. And the material is discharged when the temperature below 45-50°C.

PVC Extruder Temperature Setting

• The temperature setting of the first stage twin screw extruder is between 140 and 160°C. The temperature setting is different according to different materials. 

• The stable setting of the second stage single screw extruder is between 125 and 145°C. The temperature setting is different according to different materials.

• Set the temperature control meter, and the actual temperature reaches the set temperature which is kept for 40 minutes before it can start production. This is to ensure that the equipment has the materials left from the previous day, to be melted. This will not damage the equipment.

Production

• After the compounding and extrusion, PVC material is put into the hopper of the screw loader, and the powdery material is put into the first stage twin screw extruder through the screw feeder.

• The first stage twin screw extruder mixes the materials uniformly, and completes the plasticization and mixing at a temperature of 140-160°C, and fully disperses them evenly. Finally, the extruded mixture becomes a melt (the temperature at 130-140°C) and directly falls into the large diameter second stage single screw extruder.

• The second stage single screw extruder extrudes and pelletizes the melt at 120°C at low speed, high pressure, and then will be cooled. The temperature has dropped to 120-140°C during extrusion. Only then can the hot pelletizing of the air-cooled die face be completed, and the pellets will not stick during the pelletizing process.

• The cut pellets from the air-cooled die face are cooled by a two-stage air-cooled cyclone separator, and the pellet temperature is reduced to 35-40°C. And then passed through an air-cooled vibrating screen to reduce the pellet temperature to room temperature so that the finished products go to the product silo for packaging.