Classification of lubricants for PVC by compaction testing

Compaction testing was used to classify 10 lubricants for PVC, spanning the range of chemical types. Lubricants are defined as internal or external by their effect on compaction on being added to a standard base formulation. The results show excellent correlation by chemical type, in which the lubricants are divided into three distinct categories—external lubricants: paraffin waxes and low‐density polyethylenes; intermediate lubricants: montanic ester waxes and bisstearmides; internal lubricants: glycerol and monostearate and fatty acid alcohols. A test is proposed by which new additives may be easily classified or present lubricant systems evaluated.