Lubricant composition

Abstract

The present invention relates to a lubricating composition comprising a base oil and an antioxidant additive, said antioxidant additive comprising a phenolic antioxidant, an amine antioxidant, and a tocopherol supplement comprising at least one member of the list consisting of: beta-tocopherol, delta-tocopherol and gamma-tocopherol.The present invention also relates to a use of a lubricating composition according to the invention, in a combustion engine.

1 . A lubricating composition comprising a base oil and an antioxidant additive, wherein:
 the content by weight of the antioxidant additive is between 0.5 and 1.5%,   said antioxidant additive comprises a phenolic antioxidant, an amine antioxidant, and a tocopherol supplement,   the antioxidant additive has a content by weight of tocopherol supplement between 5 and 30%,   the tocopherol supplement comprises at least one element from the list consisting of: beta-tocopherol, delta-tocopherol and gamma-tocopherol,   the sum of the contents by weight of beta-tocopherol, delta-tocopherol and gamma-tocopherol in the tocopherol supplement is greater than 50%.   
     
     
         2 . The lubricating composition of  claim 1 , wherein the sum of the contents by weight of beta-tocopherol, delta-tocopherol and gamma-tocopherol in the tocopherol supplement is greater than 70%. 
     
     
         3 . The lubricating composition of  claim 2 , wherein the tocopherol supplement consists of a mixture of several types of tocopherols, namely between 0 and 20% of alpha-tocopherol, between 0 and 5% of beta-tocopherol, between 50 and 65% gamma-tocopherol and between 20 and 35% of delta-tocopherol. 
     
     
         4 . The lubricating composition of  claim 1 , wherein the tocopherol supplement comprises delta-tocopherol. 
     
     
         5 . The lubricating composition of  claim 4 , wherein the tocopherol supplement has a content by weight of delta-tocopherol greater than 50%. 
     
     
         6 . The lubricating composition of  claim 1 , wherein the antioxidant additive has a ratio of the contents by weight of the amine antioxidant to the phenolic antioxidant of less than 0.9, preferably less than 0.8. 
     
     
         7 . The lubricating composition of  claim 1 , wherein the base oil has a content by weight of sulfur less than 0.03% and a viscosity index greater than 120. 
     
     
         8 . Use of a lubricating composition according to  claim 1 , in a combustion engine.