LUBRICATING COMPOSITION Russian patent published in 2018 - IPC C10L1/02 C10M145/02 C10M145/14 

FIELD: chemistry.

SUBSTANCE: invention discloses the use of a comb polymer for reducing the loss in viscosity of a lubricating composition for the crankcase of an internal combustion engine, wherein the internal combustion engine is fuelled by a fuel composition comprising a fatty acid alkyl ester, wherein the comb polymer comprises, in the backbone, at least one repeat unit which is obtained from at least one polyolefin-based macromonomer, and at least one repeat unit which is obtained from at least one low molecular weight monomer selected from a group consisting of styrene monomers having 8 to 17 carbon atoms, alkyl (meth) acrylates having 1 to 10 carbon atoms in the alcohol group, vinyl esters having from 1 to 11 carbon atoms in the acyl group, vinyl ethers having 1 to 10 carbon atoms in the alcohol group, (di)alkyl fumurates having 1 to 10 carbon atoms in the alcohol group, (di)alkyl maleates having 1 to 10 carbon atoms in the alcohol group and mixtures thereof, where the molar degree of branching of the comb polymer is in the range of 0.1 to 10 mol%, and the comb polymer comprises a total of at least 80 wt%, based on the total weight of repeat units of the comb polymer, of the at least one repeat unit which is obtained from the at least one polyolefin-based macromonomer, and the at least one repeat unit which is obtained from the at least one low molecular weight monomer; wherein the comb polymer has a weight average molecular weight in the range of 100,000 to 500,000 g/mol.

EFFECT: technical result is reduction of viscosity loss of the lubricating composition for the crankcase of an internal combustion engine which is fuelled with a fuel composition which contains biodiesel.

16 cl, 7 tbl