Flat Oil Viscosity Lubricant Compositions

A lubricating oil composition comprising or resulting from the admixing of:

• (i) at least 50 mass %, based upon the weight of the lubricating oil composition, of base oil,
• (ii) at least one capped dispersant, derived from polymer having number average molecular weight (Mn) of less than 1600 g/mol, where the capped dispersant is represented by the following formula:
• wherein each R11 and R12 is individually hydrogen or a hydrocarbyl group, provided that R11 and R12 connected to the same succinimide ring are not both hydrogen;
• z is an integer from 0 to 10;
• and each R13 is individually an acetyl group, or wherein two proximate R13 groups connected to different nitrogen atoms may connect together;
• (iii) at least one magnesium containing detergent,
• (iv) at least one calcium containing detergent,
• (v) at least one comb copolymer viscosity modifier comprising the reaction product of at least the following monomers:
• (a) a hydrogenated polybutadiene-based (alk)acrylate ester macromonomer;
• (b) a C3-C8 alkyl (alk)acrylate ester monomer;
• (c) a C12-C24 alkyl (alk)acrylate ester monomer;
• and
• (d) a C1-C18 alkyl-endcapped or C6-C20 aryl-, aralkyl-, or alkaryl-endcapped C2-C6 oxyalkyl or C2-C6 oligo(alkylene glycol)-based (alk)acrylate ester monomer and/or hydroxyalkyl or H-endcapped oligo(alkylene glycol)-based (alk)acrylate monomer having the following structure (II):
• in which R2 represents hydrogen or C1-C2 alkyl, m is from 2 to 6, such that —(CH2)m— represents a linear, branched, and/or cyclic alkyl group between oxygens, n is from 1 to 10, and R1 represents H, a C1-C18 linear, branched, and/or cyclic alkyl endcap or a C6-C20 aryl, aralkyl, or alkaryl endcap,
• wherein the combination of (c) and (d) collectively comprise more than 20.0 wt % of repeat units of the comb copolymer viscosity modifier, based upon the weight of all the repeat units in the copolymer.

A concentrate comprising:

• (i) less than 50 mass %, based upon the weight of the lubricating oil composition, of base oil,
• (ii) at least one capped dispersant, having number average molecular weight (Mn) of less than 1600 g/mol, and represented by the following formula:
• wherein each R11 and R12 is individually hydrogen or a hydrocarbyl group, provided that R11 and R12 connected to the same succinimide ring are not both hydrogen;
• z is an integer from 0 to 10;
• and each R13 is individually be an acetyl group, or wherein two proximate R13 groups connected to different nitrogen atoms may connect together;
• (iii) at least one magnesium containing detergent and at least one calcium containing detergent where the calcium from detergent to magnesium from detergent ratio is 10:1 to 2:1, and
• (iv) at least one comb copolymer viscosity modifier comprising the reaction product of at least the following monomers:
• (a) a hydrogenated polybutadiene-based (alk)acrylate ester macromonomer;
• (b) a C3-C8 alkyl (alk)acrylate ester monomer;
• (c) a C12-C24 alkyl (alk)acrylate ester monomer;
• (d) a C1-C18 alkyl-endcapped or C6-C20 aryl-, aralkyl-, or alkaryl-endcapped C2-C6 oxyalkyl or C2-C6 oligo(alkylene glycol)-based (alk)acrylate ester monomer and/or hydroxyalkyl or H-endcapped oligo(alkylene glycol)-based (alk)acrylate monomer having the following structure (II):
• in which R2 represents hydrogen or C1-C2 alkyl, m is from 2 to 6, such that —(CH2)m— represents a linear, branched, and/or cyclic alkyl group between oxygens, n is from 1 to 10, and R1 represents H, a C1-C18 linear, branched, and/or cyclic alkyl endcap or a C6-C20 aryl, aralkyl, or alkaryl endcap,
• wherein the combination of (c) and (d) collectively comprise more than 20.0 wt % of repeat units of the comb copolymer viscosity modifier, based upon the weight of all the repeat units in the copolymer;
• (v) optionally, a metal alkylthiophosphate where the alky group is derived from at least one secondary alcohol;
• (vi) optionally, a molybendum containing compound;
• and
• (vii) optionally, antioxidant.

A polymethacrylate comb copolymer viscosity modifier made by polymerization of comprising at least the following monomers:

• (a) a hydrogenated polybutadiene-based (alk)acrylate ester macromonomer;
• (b) a C3-C8 alkyl (alk)acrylate ester monomer;
• (c) a C12-C24 alkyl (alk)acrylate ester monomer;
• and
• (d) a C6-C20 aryl-, aralkyl-, or alkaryl-endcapped C2-C6 oxyalkyl or C2-C6 oligo(alkylene glycol)-based (alk)acrylate ester monomer having the following structure (II):
• in which R2 represents hydrogen or C1-C2 alkyl, m is from 2 to 6, such that —(CH2)m— represents a linear, branched, and/or cyclic alkyl group between oxygens, n is from 1 to 10, and R1 represents a C6-C20 aryl, aralkyl, or alkaryl endcap,
• wherein:
• 1) the (c) C12-C24 alkyl (alk)acrylate ester monomer repeat units are present at 16 to less than 21 wt %, based upon the weight of all the repeat units in the copolymer,
• 2) the (d) C6-C20 aryl-, aralkyl-, or alkaryl-endcapped C2-C6 oxyalkyl or C2-C6 oligo(alkylene glycol)-based (alk)acrylate ester monomer repeat units are present at 3 to 7 wt %, based upon the weight of all the repeat units in the copolymer, and
• 3) the combination of (c) and (d) collectively comprise more than 20.0 wt % of repeat units of the comb copolymer viscosity modifier, based upon the weight of all the repeat units in the copolymer.

A polymethacrylate comb copolymer viscosity modifier having:

• 1) a ratio of relative KV140/relative KV20 of 1.9 or more;
• 2) a ratio of relative KV100/relative KV70 or 1.30 or more;
• and
• 3) a viscosity index (ASTM 2270D) of 320 or more, when 1), 2) and 3) are measured on a blend, having a KV100 of about 8 cSt, of the copolymer viscosity modifier and a group III base oil having a KV100 of about 4 cSt, and a viscosity index (ASTM D2270) of about 120.