Functions of Internal and External Lubrication of PVC Lubricant-2

Internal Lubrication of PVC Lubricant

An internal lubricant for PVC plays the role of softening or plasticizing. However, it is similar to a plasticizer but is comparatively less compatible with PVC due to its longer carbon chain and lower polarity. As a result, only a small number of lubricant molecules are able to infiltrate into the polymer’s molecular chains. These lubricant molecules reduce molecular chains’ mutual attraction and decrease the melt viscosity while promoting inter-molecular flow via chain slippage.

The internal lubricants for PVC decrease shear burn-in injection molding by reducing the friction between the particles before the melting of polyvinyl chloride. It leads to a reduction in the tendency to sink marks and provides a better surface finish while offering good part-size control. Thus, it makes mold-filling better, faster, and easier by reducing back pressure in extrusion.

Ester wax and oxidized polyethylene wax are commonly used internal lubricants for PVC, which can enhance the fillers’ dispersion while improving clarity.

What Can Happen if You Use the Lubricants Improperly?

The use of PVC pipe lubricant in the processing of PVC requires certain principles to be followed strictly. There should be a proper slip balance between internal and external lubrication, and the lubricants should be used in adequate amounts. If this is not the case, then the following things can happen.