Due to the high melt viscosity of CPVC, especially in injection molding, it is prone to melt fracture, so it is not suitable to use only traditional paraffin wax, stearic acid and metal soap lubricating systems. In the extrusion processing of CPVC, since CPVC has a tendency to adhere to the metal surface of the hot post-processing equipment (especially the die and die), in order to eliminate this adhesion, an external lubricant must be added to the formulation. External lubricants and CPVC resins should be immiscible.
In the CPVC molding process (especially the injection process), under the action of pressure, the mutual friction between the CPVC resins generates frictional heat. The generation of frictional heat is unfavorable to the molding process and must be controlled. Internal lubricants reduce the friction between resins during CPVC processing. The internal lubricant and CPVC resin should be compatible. It should be noted that the balance of internal and external lubrication in the formulation is key. Excessive internal lubrication will seriously affect "plasticization" and deteriorate the quality of products; excessive external lubrication will cause lubricant precipitation, and even lead to screw slippage and other phenomena that seriously affect normal production. The OP wax (montan ester wax) in the saponified wax is an ideal internal and external compound lubricant.
