Why Do We Need To Add Lubricants To PVC Heat Stabilizers?

Why do we need to add lubricants to PVC heat stabilizers? PVC has poor thermal stability, so corresponding stabilizers must be added to repair the defects of the PVC chain and absorb toxic gases such as HCL produced by PVC dechlorination in time. However, due to the processing characteristics of PVC such as high viscosity and high shear force of the screw, a corresponding amount of lubricants such as polyethylene wax must be added when adding stabilizers.

Polyethylene wax, also known as PE wax, is a white powder with an average molecular weight of generally 1500-5000 and a melting point of 100-120 degrees Celsius. It has excellent external lubrication effect in the processing of PVC, and can effectively improve the fluidity, output, dispersion, surface brightness and demolding properties of PVC during processing. Due to its large molecular weight, high melting point, and very good high-temperature stability, it shows a strong external lubrication effect under high temperature and high shear conditions.

PE wax is mostly divided into several types:

1. PE wax is produced by homopolymerization of ethylene. The PE wax produced by this method has very good external lubrication performance, high gloss, narrow molecular weight distribution, and very stable quality.
2. Sub-brand wax, PE wax obtained by purification through refining process, this type of product has low viscosity, high melting point, excellent external lubrication performance, low price, but the quality fluctuates with the changes of raw materials and processes. Due to the characteristics of the refining process, there will be more low-melting point components in the product.

3. Low molecular weight polyethylene cracking products in PVC thermal stability are usually called cracking wax. This cracking process is simple and easy to operate, but the molecular weight distribution of the product fluctuates with the production process. The quality is relatively good, but there will still be a small number of low-melting point components.

Polyethylene wax products can effectively improve the thermal stability of PVC and the fluidity during processing, increase the extrusion efficiency of PVC products, improve the surface gloss of products, and effectively reduce the precipitation phenomenon during the processing of PVC products.