PVC is vulnerable to thermal degradation during processing; hence it needs different additives to prevent its degradation upon heating and shearing to get desired articles.
Lubricants play vital role in both rigid and plasticized PVC applications. These are categorized based on functions as:
Internal Lubricants
External Lubricants
Viscosity Depressant
1. Internal
It plays the role of softening or plasticizing.
These lubricant molecules reduce molecular chains’ mutual attraction and decrease the melt viscosity while promoting inter-molecular flow via chain slippage.
Enhance the fillers dispersion while improving clarity.
2. External
The presence of the lubricant molecular layer results in the formation of a lubricating interface which lowers the friction between the processing machine and resin.
3. Viscosity Depressant
Reduces the viscosity of plastisol formulations, when added in optimum proportions.