Functions of Internal and External Lubrication of PVC Lubricant-3

Unbalanced External and Internal Lubrication

Over and under lubrication affect the product quality as the processing suffers. Too much internal slippage results in large extrusion volumes and poor material plasticization. If the external slippage is too much, extrusion speed becomes fast, but plasticization is poor. It affects the internal performance and surface quality of the extruded product.

Over lubrication leads to poor surface properties along with scorching, poor weld lines, poor impact strength, and low output. On the other hand, under lubrication causes loss of mechanical properties and poor fusion or degradation of PVC due to frictional heat.

The addition of PVC lubricants in excess amounts can influence the blending system of

PVC adversely because of the incompatibility of PVC resins and lubricants, which may result in product defects due to thermal stability issues and several other processing-related problems.

In the case of excessive internal lubricants, plasticizing torque gets smaller, and plasticizing time gets shorter. The thermal stability time is also less, and the product’s inner wall is not smooth. On the other hand, excessive external PVC lubricants may result in precipitation phenomena and decreased mechanical properties.