They are low moleculer weight substances added to the environment to reduce the pressure and forces that occur during the processing of PVC. Lubricants enhance and improve the processing properties of the polymer. Poorly balanced lubricant systems cause solids to build up on the surface of the processing equipment, in which case the equipment is disabled and clened. In short,they eliminate the problems encountered during the processing of polymers.

Lubricants are divided into two as inner lubricants and outer lubricants.

Inner Lubricants: Internal lubricants are materials that are better compatible ith PVC. They dissolve well in PVC and reduce intermolecular friction by weakening the forces between polymer molecules. Thus, thet increase the fluidity of the polymer and increase the production. Internal lubricants lower the glassy temperature(Tg) and some other properties of most PVC. With the use of internal lubricants,there is no problem when writing on the plastic surface and painting the surface.

Outer Lubricants: They are substances that are incompatible with PVC components at processing temperatures(insoluble in PVC or not homogeneously dispersed.) Therefore, such lubricant act as interfaces between the PVC compounds and the metal surfaces of the processing equipment and prevent the molten PVC from adhering to the processing equipent. The behavior of PVC in processing equipment depends on this external lubricants content. In addition,these substances reduce the friction between the polymer particles during the plasticization process and prevent the temperature rise.