In terms of chemical composition, theyre not very different from PAOs, said Massimo Ciali, global market manager of lubricants for Sasols Olefins and Surfactants division. And they act very similarly in lubricants. Ciali noted that the definition adopted by the associationincluded base oil interchange guidelines. Sasol hopes the definition andguidelines make it easier for lube formulators to substitute PIOs for PAOs. The guidelines allow interchange of PIOs with each other and with PAOs without the need for additional engine tests.
ATIEL maintains definitions of base stock categories which, except for the new Group VI category, are identical to those maintained by the American Petroleum Institute for North America. Groups I, II and III represent mineral based oils with increasingly stringent limits for aromatics, viscosity index and sulfur content. Group IV is for PAOs, while Group V is a catchall for any base stocks that do not fall into the other categories.
PIOs are similar to PAOs in that they are synthetic linear chains of alphaolefins. Ciali said Sasol convinced ATIEL that it made sense to define a new category in order to reduce the amount of testing required of formulators trying to license motor oils that contain PIOs.
Information about the associations definition is available at www.atiel.org