Lubricants improve the fluidity and demoulding of the resin. In processing, it reduces friction between resin and processing machinery, the friction between resin and resin, so that it reduces the torque to save the energy. Lubricants also increase the surface smoothness of the finished products and prevent the adhesion between the products.
There’re internal and external lubricants:
Internal lubricant has a large affinity for the resin, the effect is to reduce the force between large molecular
External lubricant has a small affinity for the resin, the effect is to reduce the friction between resin and processing machinery.
Paraffin wax and FT wax are both lubricants of PVC to decrease the friction force of material and processing equipment surface, thereby reducing the flow resistance of melt, reducing the viscosity of melt, improving the fluidity of melt, avoiding the friction between melt and equipment, and improving the surface finish of products.
Paraffin wax is normally used as the external of PVC. It is easily spread, improve flow properties of PVC and provide a good removal,
sliding and anti-blocking effects to the final compound. They’re useful for the processes such as extrusion of rigid piping, injection molding, and flexible PVC.
Ft wax is an excellent external lubricant and also has the internal lubrication. It has a high melting point, narrow carbon distribution. Comparing with paraffin wax, its dosage is much lower. It has better thermal stability and aging resistance. It also improves the surface physical properties of the finished products.
Extrusion and injection molding.
Mainly use internal lubricant to reduce the viscosity, improve the fluidity and be easy to die out. Ester and wax are used together.
Molding and laminating.
Mainly use external lubricants, and commonly use wax.
Opaque products, such as plates and pipes, are often used with metal soaps, paraffin, and stearic acid.
Cable material normally uses high melting point paraffin wax as the lubricant.