Pour point depressants (PPDs) have several technical specifications, including:
Appearance: Clear, homogeneous liquid with no separation
Specific gravity at 30°C: 0.900–0.920
Kinematic viscosity at 100°C, cSt: 60–190
Flash point, °C: 150 minimum
Miscibility/homogeneity in oil: Should be clear and homogeneous after standing for 24 hours and after centrifuging at 1450 rpm for 5 minutes
Low temperature stability: Should be clear and homogeneous after keeping at the pour point of the blend for 24 hours and after thawing to ambient temperature
PPDs work by modifying the interface between the crystallized wax and the oil, allowing the oil to remain pumpable. Some common PPDs include polyalkylnaphthalene, polyalkyphenyl esters, or polyalkylmethacrylate.Most PPDs are solid or waxy at room temperature and need to be warmed up before use. Fluid PPDs that are pumpable at ambient temperatures are also available.