Functions of Internal Lubricants

Internal lubricants are compounds that are intimately mixed with PVC resin during the compounding or blending process. They serve multiple purposes in PVC processing:

1. Reducing Friction: 

Internal lubricants reduce the friction between PVC particles and processing equipment, such as extruders and injection moulding machines. This lubrication is essential to prevent PVC from sticking to metal surfaces and causing processing difficulties.

2. Enhancing Flowability: 

These lubricants improve the flowability of PVC melt, making it easier to process. This is particularly crucial in applications like extrusion, where a smooth and uniform flow of PVC is essential for quality end products.

3. Minimizing Shear Heat: 

The friction generated during PVC processing can lead to excessive shear heat, which may degrade the polymer. Internal lubricants help reduce shear heat, preventing polymer breakdown and maintaining product integrity.

4. Controlling Fusion Time: 

In applications involving multiple layers or co-extrusion, internal lubricants can be tailored to control fusion times. This ensures proper bonding between PVC layers or with other materials.