Abstract: An ester resulting from an esterification reaction between at least one polyfunctional alcohol and at least one polyfunctional carboxylic acid using a chain stopping agent to form ester bonds with the remaining hydroxyl or carboxyl groups is disclosed. The polyfunctional carboxylic acid comprises an aliphatic dicarboxylic acid containing from 9 to 18 carbon atoms, dimerised and/or trimerised fatty acids or mixtures thereof, with the proviso that dimerised and trimerised fatty acids do not constitute more than 80% by weight of the total amount of polyfunctional carboxylic acid used. The chain stopping agent may be a monocarboxylic acid or a monofuntional alcohol having at least 14 carbon atoms. The complex esters have a kinematic viscosity at 100 C of from 30 to 1000 cSt, preferably from 30 to 200 cSt.

Abstract: An ester based lubricant, particularly suitable for 4-stroke engines comprises at least one ester of a saturated, branched chain monohydric alcohol having at least 8 carbon atoms and a saturated branched chain aliphatic monocarboxylic acid having at least 10 carbon atoms. The esters have a kinematic viscosity of at most 35 cSt (40° C.), a non-polarity index of at least 100, a Noack evaporation loss of at most 10% and a pour point below −30° C.

Abstract: An ester based lubricant, particularly suitable for 4-stroke engines comprises at least one ester of a saturated, branched chain monohydric alcohol having at least 8 carbon atoms and a saturated branched chain aliphatic monocarboxylic acid having at least 10 carbon atoms. The esters have a kinematic viscosity of at most 35 cSt (40.degree. C.), a non-polarity index of at least 100, a Noack evaporation loss of at most 10% and a pour point below -30.degree. C.

Abstract: The invention provides a polyester based on dimeric fatty acid, a glycol without hydrogen atoms at an alpha carbon atom in which a C3-C12 monoalcohol chainstopper is present and which contains approximately equivalent quantities of acid and alcohol groups. Preferably the dimer acid contains 36 carbon atoms and the monoalcohol is a branched chain C6-C10 alkanol. The invention also provides lubricant compositions comprising 30-2% (w.w.) of the polyester and 70-98% (w.w.) of an synthetic lubricant base.