Lubricants usually act by modifying the viscosity of the melt, by introducing different surface energies at the interface between the phases. Very often the same material can be used for internal lubrication (at a low addition) and for mould release (at a higher level). However, the addition of multi-functional systems, in which an apparently high-priced lubricant can more than pay for itself by modifying other properties, such as:
- Impact strength
- Low-temperature performance
- Improved distribution of other additives, and even
- Moisture and gas barrier properties
The addition level is usually about 0.5-3.0%, depending on the individual recipe and process, but a high-performance additive can be effective at as low as 0.1% dosage as well.
- Metallic Stearates
- PE Wax