What are the abnormal phenomena in the production of PVC compound?

1. Granulation: Mixing: PVC compound are mixed unevenly, and plasticizers wrap PVC to produce particles; Dead corner: Refers to the excessive gelation of residual materials due to the incomplete cleaning of the material barrel during mixing in different batches;Ejection: Insufficient temperature, poor gelation, and particle formation; A filter can be used to increase the back pressure and allow PVC with poor gelation to flow back. Poor gelation: related to the machine and operating temperature. 2. Impurity particles (irregularly shaped, angular particles): Impurities mainly come from CCR and CaCO3 in raw materials;There are very few impurities from stabilizers: less in the calcium zinc series and more in the lead series. Agglomeration: If the extrusion temperature is too high, the cooling efficiency of the air cooler is low, resulting in agglomeration; The extrusion temperature is normal, and the occurrence of agglomeration is generally related to the stabilizer in the raw material. Clustering is related to operation and can be avoided by adjusting the temperature.

2. Impurity particles (irregularly shaped, angular particles):Impurities mainly come from CCR and CaCO3 in raw materials;There are very few impurities from stabilizers: less in the calcium zinc series and more in the lead series. Agglomeration: If the extrusion temperature is too high, the cooling efficiency of the air cooler is low, resulting in agglomeration; The extrusion temperature is normal, and the occurrence of agglomeration is generally related to the stabilizer in the raw material. Clustering is related to operation and can be avoided by adjusting the temperature.

3. Color difference: human factor - uneven color matching or failure to cut according to standards; Material related; The stabilizer is poor, and it keeps stirring and heating up during the color matching process, causing PVC to deteriorate and turn yellow. Pore: due to human operation - high processing temperature, insufficient external lubricant, and gasification of low molecular weight substances; Machine reason - During the extrusion process, the air entrained by the material is squeezed out, and poor exhaust from the machine can cause small pores.