Lubricants & Processing Aids in Plastic Compounding

A small percentage of the right lubricant can eliminate die build-up, reduce torque and smooth out an otherwise problematic extrusion run.

By Siya Polymer & Speciality Chemicals Technical Team · Manufacturer & Supplier, Maharashtra, India

Internal vs External Lubricants

Internal lubricants reduce friction between polymer molecules, lowering melt viscosity and easing internal flow, which helps with mixing and moulding. External lubricants migrate to the surface and reduce friction between the polymer and metal processing equipment, easing release from moulds and reducing die build-up.

Fluoropolymer Processing Aids

Fluoropolymer-based processing aids (PPA) are used at very low loadings, typically under 1%, to coat die surfaces and eliminate melt fracture - the rough, distorted surface defect that appears at high extrusion output rates, particularly in polyolefin film and pipe extrusion.

Common Signs You Need a Processing Aid

Consider a processing aid or lubricant if you're seeing:

• Melt fracture or surface roughness at higher line speeds
• Die build-up requiring frequent cleaning stops
• High motor torque or amp draw during extrusion
• Poor mould release causing cycle delays

Choosing the Right Type

Selection depends on the base resin, processing method (injection vs extrusion) and the specific symptom you're trying to solve - internal lubricants, external lubricants and PPAs address different problems and are sometimes combined.