PVC lubricants - PVC type of lubricant

Common PVC lubricants main properties are as follows :
( 1 ) Calcium stearate :
White powder , melting point 148-155 ℃, non-toxic, have excellent lubricity and processability, no curing pollution , and basic lead salts and lead soap and use, to increase the   Methyl tin rate of gelation , the dosage is generally 0.1-0.4PHR.
( 2 ) oxidized polyethylene wax
White or light yellow powder or granules contain small amounts of oxidized polyethylene wax , although polar group , is still compatible with the PVC , but the lubricating high efficiency, can improve lubrication between the polymer and the metal , improving the extrusion efficiency, improve a colorant dispersion, gives a good product transparency and gloss . Dosage 0.1-0.5PHR.
( 3 ) Stearic acid
White or light yellow granules , mp 70-71 ℃. Evaporate slowly at 90-100 ℃ , the hard PVC processing as external lubricant , the dosage is generally 0.2-0.5PHR, and to prevent fouling of the chromatographic effect, but with excessive easy to spray cream.
( 4 ) Glyceryl stearate
Powder substance , melting point 85-87 ℃, with excellent heat resistance and mobility, increase the amount of filler , and may contribute to plastics . And waxes and use, can improve the titanium dioxide anatase  thermal stability of PVC-U . Dosage is 0.2-0.6PHR.
In practice, it was found that two or more lubricant when used in combination with the emergence of a different effect when used alone . In profile formulations, they use complex methods
( 5 ) Paraffin
Melting point 57-63 ℃, no polar group , is a typical external lubricant . Because of its low melting point, easy to evaporate , the melt viscosity is small and only in a narrow range of a lubricant , suitable for single or double screw extruder , the general amount of 0.1-0.8PHR. This product transparency is poor , easy to whiten.
( 6 ) Polyethylene wax
White powder , a softening point of about 100-117 ℃, due to its relatively large molecular weight , high melting point , low volatility and therefore at higher temperature and shear rate , but  pvc additive also shows a clear lubricating effect . For rigid PVC single , twin-screw extruder , the usual dose is 0.1-0.5PHR.