Engine oil with low-temperature pumpability

Abstract

A lubricating composition comprising a polymer blend of a modified styrene-maleic anhydride copolymer and a poly(meth)acrylate copolymer, the polymer blend being effective in maintaining a pumpable fluid at low temperatures.

Description

Technical Field

[0001] The present disclosure relates to lubricants comprising polymer mixtures effective to provide improved viscosity characteristics at low temperatures such as temperatures up to about -40°C.

Background Art

[0002] Engine oils or lubricants intended for use in automotive engines and diesel engines generally include a base oil of lubricating viscosity and one or more additives. Modern industrial standards are increasing the requirements for the low-temperature performance of such engine oils. Low-temperature characteristics can suggest several performance parameters, for example, through Brookfield viscosity, Cold Cranking Simulator (CCS) test, pour point, and Mini Rotary Viscometer (MRV) test.

[0003] The low-temperature performance of engine oils can be improved by selecting the additives used in formulating the oils. Pour point depressants are one common additive included in formulated engine oils to help improve the fluidity of the oil at low temperatures. The pour point is a measure of the temperature at which a sample of the lubricant begins to flow and can be determined as described in ASTM D 5950. Often, when engine oils have a low pour point, they can also have other good low-temperature characteristics such as a low cloud point, a low cold filter plugging point, and / or a low cold cranking viscosity. However, in some cases, formulated oils that can exhibit satisfactory low-temperature performance with respect to the pour point can still exhibit unsatisfactory low-temperature viscosity characteristics. In fact, formulated engine oils have been found to fail important low-temperature viscosity characteristics such as the Mini Rotary Viscometer (MRV) test, even though they meet the standards established for the oil with respect to the cloud point and / or pour point.

[0004] The Mini Rotary Viscometer Test (MRV) evaluates the mechanism of the low-temperature pumpability of fluids and is a low-shear rate measurement. The MRV is measured according to ASTM D 4684 and is sometimes called the low-temperature pump viscosity. In the MRV evaluation, the sample is pre-treated to have a specific thermal history, which may include heating, slow cooling, and immersion cycles. In the MRV test, the apparent yield stress and viscosity are measured, which, if greater than a threshold value, suggest potential lubricant pumpability problems.

Summary of the Invention

[0005] In one approach or embodiment, a low-temperature stable lubricating composition is described herein that exhibits good pumpability, where the pumpability is measured according to the MRV test of ASTM D4684 at about -40°C. In one approach, the composition includes a base oil of lubricating viscosity and a polymer additive that includes a blend of a modified styrene-maleic anhydride copolymer and a poly(meth)acrylate copolymer effective to maintain a pumpable fluid.

[0006] In another approach, the low temperature stability lubricating composition of the previous paragraph may also include several optional features in any combination. These optional features include one or more of the following: the lubricating composition further includes one or more of a succinimide dispersant, a boronated succinimide dispersant, overbased calcium sulfonate, overbased magnesium sulfonate, zinc dialkyldithiophosphate, an alkylated diphenylamine antioxidant, an antifoaming agent, or a combination thereof; and / or the modified styrene-maleic anhydride copolymer is an esterified styrene-maleic anhydride copolymer; and / or the esterified styrene-maleic anhydride copolymer is esterified with a long-chain alcohol having an alkyl chain length of 10 to 24 carbons; and / or the esterified styrene-maleic anhydride copolymer has a number average molecular weight of about 10,000 to about 100,000; and / or the poly(meth)acrylate copolymer includes a reactant selected from C1-C24 linear or branched alkyl (meth)acrylate reactants; and / or the number average molecular weight of the poly(meth)acrylate copolymer is about 20,000 or more; and / or the lubricating composition includes a polymer additive blend of about 1 weight percent or less, preferably about 0.5 to about 0.6 weight percent; and / or the ratio of the modified styrene-maleic anhydride copolymer to the poly(meth)acrylate copolymer is about 1:2 to about 1:0.7; and / or the polymer additive blend includes about 40 weight percent to about 60 weight percent of the modified styrene-maleic anhydride copolymer based on the total weight of the modified styrene-maleic anhydride copolymer and the poly(meth)acrylate copolymer.

[0007] In other approaches or embodiments, methods for maintaining the pumpable viscosity of a lubricating composition in accordance with the MRV test of ASTM D4684 are also described herein. In one approach, the method includes adding to the lubricating composition an additive of any of the preceding paragraphs of this summary that is effective to maintain a pumpable fluid, as evidenced by the measured MRV performance at temperatures up to about -40°C. In other approaches or embodiments, the use of the polymer additives described in this summary to achieve a passing MRV pumpability at the qualified level in accordance with ASTM D4684 is described herein.

[0008] The following definitions of terms are provided to clarify the meaning of specific terms used herein.

[0009] The terms "oil composition", "lubrication composition", "lubricating oil composition", "lubricating oil", "lubricant composition", "lubricating composition", "fully formulated lubricant composition", "lubricant", "crankcase oil", "crankcase lubricant", "engine oil", "engine lubricant", "motor oil", and "motor lubricant" are considered synonymous and fully interchangeable technical terms that refer to a final lubricating product that includes a minor amount of an additive composition in addition to a major amount of base oil.

[0010] As used herein, the terms "additive package", "additive concentrate", "additive composition", "engine oil additive package", "engine oil additive concentrate", "crankcase additive package", "crankcase additive concentrate", "motor oil additive package", "motor oil concentrate" are considered synonymous and fully interchangeable technical terms that refer to a part of a lubricating oil composition excluding a major amount of the base oil feedstock mixture. The additive package may or may not include a viscosity index improver or a pour point depressant.

[0011] The term "overbased" relates to metal salts such as sulfonates, carboxylates, salicylates, and / or phenates where the amount of metal present exceeds the stoichiometric amount. Such salts can have a conversion level greater than 100% (i.e., they can contain more than 100% of the theoretical amount of metal required to convert the acid to its "normal salt", "neutral salt"). Often, the expression "metal ratio", abbreviated as MR, is used to indicate the ratio of the total chemical equivalents of metal in an overbased salt to the chemical equivalents of metal in the neutral salt, according to known chemical reactivity and stoichiometry. In a normal or neutral salt, the metal ratio is 1, but in an overbased salt, the MR is greater than 1. These are generally referred to as overbased, highly basic, or superbasic salts and may be salts of organic sulfuric acids, carboxylic acids, salicylates, and / or phenols.

[0012] As used herein, the terms "hydrocarbyl substituent" or "hydrocarbyl group" are used in their ordinary sense and are known to those of ordinary skill in the art. Specifically, it refers to a group having a carbon atom directly bonded to the remainder of the molecule and having predominantly hydrocarbon character. Each hydrocarbyl group is independently selected from a hydrocarbon substituent and a substituted hydrocarbon substituent containing one or more of a halo group, a hydroxyl group, an alkoxy group, a mercapto group, a nitro group, a nitroso group, an amino group, a pyridyl group, a furyl group, an imidazolyl group, oxygen, and nitrogen, and two or fewer non-hydrocarbon substituents are present per ten carbon atoms in the hydrocarbyl group.

[0013] As used herein, the terms "hydrocarbylene substituent" or "hydrocarbylene group" are used in their ordinary meaning well known to those skilled in the art. Specifically, it refers to a group that is directly bonded to the remainder of the molecule by carbon atoms at two locations in the molecule and mainly has hydrocarbon characteristics. Each hydrocarbylene group is independently selected from divalent hydrocarbon substituents, and the substituted divalent hydrocarbon substituent is a halo group, an alkyl group, an aryl group, an alkylaryl group, an arylalkyl group, a hydroxyl group, an alkoxy group, a mercapto group, a nitro group, a nitroso group, an amino group, a pyridyl group, a furyl group, an imidazolyl group, oxygen, and nitrogen, and there are two or less non-hydrocarbon substituents per 10 carbon atoms in the hydrocarbylene group.

[0014] As used herein, the term "weight percent" means the percentage that the stated component represents relative to the total weight of the composition, unless otherwise expressly stated.

[0015] As used herein, the terms "soluble", "oil-soluble", or "dispersible" may indicate that a compound or additive is soluble, soluble, miscible, or suspendable in any proportion in oil, but not necessarily so. However, the foregoing terms mean that they are soluble, suspendable, soluble, or stably dispersible in oil to such an extent that they can exert their intended effects, for example, in an environment where oil is used. Further, if desired, other additives can be incorporated, and it may also be possible to incorporate higher levels of specific additives.

[0016] As used herein, the term "TBN" is used to indicate the total base number in mg KOH / g when measured by the method of ASTM D2896 or ASTM D4739 or DIN 51639-1.

[0017] As used herein, the term "alkyl" refers to a straight-chain, branched-chain, cyclic, and / or substituted saturated chain moiety of about 1 to about 100 carbon atoms.

[0018] As used herein, the term "alkenyl" refers to a straight-chain, branched-chain, cyclic, and / or substituted unsaturated chain moiety having from about 3 to about 10 carbon atoms.

[0019] As used herein, the term "aryl" refers to monocyclic and polycyclic aromatic compounds that can contain alkyl, alkenyl, alkylaryl, amino, hydroxyl, alkoxy, halo substituents, and / or heteroatoms including, but not limited to, nitrogen, oxygen, and sulfur.

[0020] The lubricants, component combinations, or individual components herein may be suitable for use in various types of internal combustion engines. Suitable engine types may include, but are not limited to, heavy-duty diesel, passenger vehicle, light-duty diesel, medium-speed diesel, or marine engines. The internal combustion engine can be a diesel fuel engine, gasoline fuel engine, natural gas fuel engine, biofuel engine, mixed diesel / biofuel fuel engine, mixed gasoline / biofuel fuel engine, alcohol fuel engine, mixed gasoline / alcohol fuel engine, compressed natural gas (CNG) fuel engine, or a mixture thereof. The diesel engine may be a compression ignition engine. The gasoline engine can be a spark ignition engine. The internal combustion engine can also be used in combination with an electric power source or battery power. An engine configured as such is commonly known as a hybrid engine. The internal combustion engine can be a two-stroke, four-stroke, or rotary engine. Suitable internal combustion engines include marine diesel engines (such as inland vessels), aircraft piston engines, low-load diesel engines, and engines for motorcycles, automobiles, locomotives, and trucks.

[0021] An internal combustion engine can include one or more components of aluminum alloy, lead, tin, copper, cast iron, magnesium, ceramic, stainless steel, composite materials, and / or mixtures thereof. The components may be coated, for example, with diamond-like carbon coating, lubricating coating, phosphorus-containing coating, molybdenum-containing coating, graphite coating, nanoparticle-containing coating, and / or mixtures thereof. The aluminum alloy may include aluminum silicate, aluminum oxide, or other ceramic material. In one embodiment, the aluminum alloy is an aluminum silicate surface. As used herein, the term "aluminum alloy" is synonymous with "aluminum composite" and is intended to describe a component or surface that contains aluminum and another component that mix or react at the microscopic level or near the microscopic level, regardless of its detailed structure. This includes not only conventional alloys having metals other than aluminum, but also composite or alloy-like structures having non-metallic elements or compounds such as ceramic-like materials.

[0022] The lubricating oil composition for an internal combustion engine may be suitable for any engine lubricant, regardless of the sulfur, phosphorus, or sulfate ash content (ASTM D-874). The sulfur content of the engine oil lubricant may be about 1 wt% or less, or about 0.8 wt% or less, or about 0.5 wt% or less, or about 0.3 wt% or less, or about 0.2 wt% or less. In one embodiment, the sulfur content may range from about 0.001 wt% to about 0.5 wt%, or from about 0.01 wt% to about 0.3 wt%. The phosphorus content may be about 0.2 wt% or less, or about 0.1 wt% or less, or about 0.085 wt% or less, or about 0.08 wt% or less, or even about 0.06 wt% or less, about 0.055 wt% or less, or about 0.05 wt% or less. In one embodiment, the phosphorus content may be from about 50 ppm to about 1000 ppm, or from about 325 ppm to about 850 ppm. The total sulfate ash content may be about 2 wt% or less, or about 1.5 wt% or less, or about 1.1 wt% or less, or about 1 wt% or less, or about 0.8 wt% or less, or about 0.5 wt% or less. In one embodiment, the sulfate ash content may be from about 0.05 wt% to about 0.9 wt%, or from 0.1 wt% or about 0.2 wt% to about 0.45 wt%. In another embodiment, the sulfur content may be about 0.4 wt% or less, the phosphorus content may be about 0.08 wt% or less, and the sulfate ash may be about 1 wt% or less. In yet another embodiment, the sulfur content may be about 0.3 wt% or less, the phosphorus content may be about 0.05 wt% or less, and the sulfate ash may be about 0.8 wt% or less.

[0023] In one embodiment, the lubricating oil composition is an engine oil, and the lubricating oil composition may have (i) a sulfur content of about 0.5 wt% or less, (ii) a phosphorus content of about 0.1 wt% or less, and (iii) a sulfate ash content of about 1.5 wt% or less.

[0024] In one embodiment, the lubricating oil composition is suitable for a two-stroke or four-stroke marine diesel internal combustion engine. In one embodiment, the marine diesel combustion engine is a two-stroke engine. In some embodiments, the lubricating oil composition is not suitable for a two-stroke or four-stroke marine diesel internal combustion engine for one or more reasons including, but not limited to, the high sulfur content of the fuel used to power the marine engine and the high TBN required for an engine oil suitable for marine use (e.g., greater than about 40 TBN for an engine oil suitable for marine use).

[0025] In some embodiments, the lubricating oil composition is suitable for use in engines powered by low-sulfur fuels such as fuels containing about 1% to about 5% sulfur. Highway vehicle fuel contains about 15 ppm sulfur (or about 0.0015% sulfur).

[0026] Low-speed diesel typically refers to marine engines, medium-speed diesel typically refers to locomotives, and high-speed diesel typically refers to highway vehicles. The lubricating oil composition may be suitable for only one or all of these types.

[0027] Furthermore, the lubricants of the present specification meet one or more industry specification requirements such as ILSAC GF-3, GF-4, GF-5, GF-6, PC-11, CF, CF-4, CH-4, CK-4, FA-4, CJ-4, CI-4 Plus, CI-4, API SG, SJ, SL, SM, SN, SN PLUS, ACEA A1 / B1, A2 / B2, A3 / B3, A3 / B4, A5 / B5, C1, C2, C3, C4, C5, E4 / E6 / E7 / E9, Euro5 / 6, JASO DL-1, Low SAPS, Mid SAPS, or Dexos1 (trademark), Dexos2 (trademark), MB-Approval 229.1, 229.3, 229.5, 229.51 / 229.31, 229.52, 229.6, 229.71, 226.5, 226.51, 228.0 / .1, 228.2 / .3, 228.31, 228.5, 228.51, 228.61, VW 501.01, 502.00, 503.00 / 503.01, 504.00, 505.00, 505.01, 506.00 / 506.01, 507.00, 508.00, 509.00, 508.88, 509.99, BMW Longlife-01, Longlife-01FE, Longlife-04, Longlife-12FE, Longlife-14FE+, Longlife-17FE+, Porsche A40, C30, Peugeot Citroen Automobiles B71 2290, B71 2294, B71 2295, B71 2296, B71 2297, B71 2300, B71 2302, B71 2312, B71 2007, B71 2008, Renault RN0700, RN0710, RN0720, Ford WSS-M2C153-H, WSS-M2C930-A, WSS-M2C945-A, WSS-M2C913A, WSS-M2C913-B, WSS-M2C913-C, WSS-M2C913-D, WSS-M2C948-B, WSS-M2C948-A, GM 6094-M, Chrysler MS-6395, Fiat 9.55535 G1, G2, M2, N1, N2, Z2, S1, S2, S3, S4, T2, DS1, DSX, GH2, GS1, GSX, CR1, Jaguar Land Rover STJLR.03.5003, STJLR.03.5004, STJLR.03.It may be suitable to meet the specifications of original equipment manufacturers such as 5005, STJLR.03.5006, STJLR.03.5007, STJLR.51.5122, or the specifications of past or future PCMOs or HDDs not described in this specification. In some embodiments for passenger car motor oil (PCMO) applications, the amount of phosphorus in the final fluid is 1000 ppm or less, or 900 ppm or less, or 800 ppm or less.

[0028] Other hardware may not be suitable for use with the disclosed lubricants. The term "functional fluid" encompasses various fluids including, but not limited to, tractor hydraulic fluids, power transmission fluids including automatic transmission fluids, continuously variable transmission fluids and manual transmission fluids, hydraulic fluids including tractor hydraulic fluids, some gear oils, power steering fluids, fluids used in wind turbines, compressors, some industrial fluids, and fluids associated with components of power transmission devices. It should be noted that within each of these fluids, such as automatic transmission fluids, there are various different types of fluids for various different transmissions having different designs that require fluids with significantly different functional characteristics. This is in contrast to the term "lubricating fluid" which is not used for power generation or transmission.

[0029] For example, with respect to tractor hydraulic fluids, these fluids are general-purpose fluids used for all lubricant applications in tractors except for lubricating the engine. These lubrication applications may include lubrication of the gearbox, power take-off and clutch, rear axle, reduction gears, wet brakes, and hydraulic accessories.

[0030] When the functional fluid is an automatic transmission fluid, the automatic transmission fluid must have sufficient friction for the clutch plate to transmit power. However, the friction coefficient of the fluid tends to decrease due to the influence of temperature as the fluid is heated during operation. It is important for the working fluid of a tractor or the automatic transmission fluid to maintain a high friction coefficient at high temperatures; otherwise, the brake system or the automatic transmission may malfunction. This is not a function of engine oil.

[0031] Tractor fluids, such as Super Tractor Universal Oil (STUO) or Universal Tractor Transmission Oil (UTTO), may combine the performance of engine oil with that of the transmission, differential, final drive planetary gears, wet brakes, and hydraulic performance. Many of the additives used to formulate UTTO or STUO fluids are functionally similar, but if not properly incorporated, they may have detrimental effects. For example, some anti-wear and extreme pressure additives used in engine oil can be highly corrosive to the copper components of hydraulic pumps. Detergents and dispersants used for the performance of gasoline or diesel engines can be harmful to the performance of wet brakes. Friction modifiers specific to quiet wet brake squeal may lack the thermal stability required for engine oil performance. Each of these fluids is designed to meet the specific and stringent requirements of the manufacturer, regardless of functionality, tractor, or lubricity.

[0032] The present disclosure provides a novel lubricating oil blend formulated for use as an automotive crankcase lubricant. The present disclosure provides a novel lubricating oil blend formulated for use as a crankcase lubricant for 2T and / or 4T motorcycles. Embodiments of the present disclosure are suitable for crankcase applications and may provide a lubricating oil having improvements in characteristics such as air entrainment, alcohol fuel compatibility, antioxidant properties, antiwear performance, biodiesel compatibility, bubble reduction characteristics, friction reduction, fuel economy, pre-ignition prevention, rust inhibition, sludge and / or soot dispersibility, piston cleanliness, deposit formation, and water resistance.

[0033] The engine oil of the present disclosure may be formulated by adding one or more additives to a suitable base oil formulation, as described in detail below. The additives may be combined with the base oil in the form of an additive package (or concentrate), or alternatively, may be combined individually with the base oil (or a mixture of both). The fully formulated engine oil may exhibit improved performance characteristics based on the additives added and their respective proportions.

[0034] As used herein, polymerizable reactants and / or monomers that form a polymer or copolymer are described. Unless otherwise indicated, a polymer generally refers to a polymer of one type of monomer, and a copolymer refers to a polymer from two or more types of monomers. Reactants or monomers generally refer to compounds within the reaction mixture prior to polymerization, and monomer units or (alternatively) repeating units refer to the reactants or monomers polymerized within the polymer chain. The various monomers herein are often polymerized randomly within the backbone as monomer units or repeating units. When the discussion refers to a reactant or monomer, it also means the resulting monomer unit or repeating unit derived therefrom in the polymer. Similarly, when the discussion refers to a monomer unit or repeating unit, it also means the reactant or monomer mixture used to form the polymer with the relevant monomer or repeating units therein.

[0035] Further details and advantages of the present disclosure are in part described in the following description and / or may be learned by the practice of the present disclosure. The details and advantages of the present disclosure may be realized and achieved by the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the claimed present disclosure.

Mode for Carrying Out the Invention

[0036] Engine or crankcase lubricant compositions are generally used in vehicles including spark ignition and compression ignition engines to provide friction reduction and other advantages. Such engines, to name just a few examples, can be used for automotive, truck, and / or train applications and can be operated with fuels including, but not limited to, gasoline, diesel, alcohol, biofuel, compressed natural gas, etc. These engines may include hybrid electric engines that include both an internal combustion engine and an electric or battery power source, and / or advanced hybrids or internal combustion engines that include an automatic engine stop function when the vehicle is stationary.

[0037] The present disclosure describes unique blends of polymer additives and lubricating compositions suitable for use as engine lubricants, such as automotive crankcase lubricants, that include such polymer blends, which in some cases can meet or exceed the ILSAC GF-6 and / or API CK lubricant standards, provide robust functionality at temperatures down to about -40°C, and specifically meet or exceed the pumpability performance of the industry MRV test (ASTM D4684). Other lubricating compositions expected to operate at extremely low temperatures, such as automotive transmissions or gearboxes, industrial or personal machinery, metalworking, turbines, gear oils, etc., but not limited to these, can also benefit from the polymeric surfactants of the present disclosure.

[0038] In one aspect, the present disclosure provides a blend of at least two distinct polymer additives in a final lubricant composition at a low treatment rate, such as a treatment rate of about 1 weight percent or less (or about 0.8 weight percent or less, about 0.6 weight percent or less, or about 0.5 weight percent or more), and provides acceptable low temperature pumpability as measured by the MRV test from ASTM D4684. Specifically, the final lubricant composition of the present disclosure achieves MRV parameters at the qualified level including an MRV viscosity at a test temperature with an oil grade of less than 60,000 cP and an MRV yield stress of less than 35 in an effective amount and ratio, and includes a blend of one or more poly(meth)acrylate copolymers and one or more modified styrene-maleic anhydride copolymers.

[0039] Modified styrene-maleic anhydride copolymer: In one aspect, the first copolymer of the polymer blend for achieving good low temperature pumpability is a modified styrene-maleic anhydride copolymer, specifically, an esterified styrene-maleic anhydride copolymer partially or completely esterified with one or more long-chain linear or branched alcohols having an alkyl chain length of 10 to 24 carbons. In some approaches, this copolymer has a repeating unit of Formula I derived from a residue of styrene and a repeating unit of Formula IIa and / or IIb derived from a residue of maleic anhydride that is completely or partially esterified, wherein R is independently a C12-C18 linear or branched alkyl group.

[0040]

Chemical formula

[0041] In some approaches, the modified styrene-maleic anhydride copolymer has a polymer backbone of a styrene-maleic anhydride copolymer containing about 30 to about 70 weight percent of repeating units derived from styrene, and in other approaches, contains about 40 to about 60 weight percent of units derived from styrene.

[0042] The modified styrene-maleic anhydride copolymer can be prepared by first polymerizing styrene and maleic anhydride (or maleic acid) under conditions suitable for forming the copolymer. The polymerization may proceed until the desired molecular weight is achieved, such as a number average molecular weight of about 10,000 to about 100,000, or in other approaches, about 30,000 to about 50,000. The polymer may also have a polydispersity index in the range of about 4 or less, about 3 or less, or about 2.5 or less, and about 2 or more, or about 2.5 or more. As used herein, the polydispersity index is the weight average molecular weight divided by the number average molecular weight. In some approaches, the polymerization can be initiated by a suitable catalyst such as a free radical initiator containing a peroxide catalyst such as benzoyl peroxide, butyl peroxide, or di-t-butyl peroxide. If necessary, a solvent or diluent may be used in the polymerization.

[0043] The styrene-maleic anhydride copolymer is then esterified with a long-chain alcohol and, in some approaches, with a mixture of long-chain alcohols. Generally, suitable alcohols are straight-chain or branched alcohols having 18 to 30 carbons, in other approaches, straight-chain or branched alcohols having 20 to 28 carbons, and in still other approaches, straight-chain or branched alcohols having 12 to 20 carbons, i.e., straight-chain or branched alcohols having 10 or more carbons. Typically, the esterification occurs with approximately 2 moles of alcohol per mole of maleic anhydride in the polymer. Esterification is well known to those skilled in the art, and an exemplary reaction can proceed for about 3 to about 6 hours at a temperature of about 160°C to 200°C. An esterification catalyst such as methanesulfonic acid or dodecylbenzenesulfonic acid can be added. This reaction can also occur in the presence of a suitable solvent or diluent such as a heavy aromatic solvent. Maleic anhydride is generally esterified after polymerization, but it may be esterified before polymerization. In some approaches, the copolymer is at least about 90% esterified.

[0044] The molecular weight of any embodiment of this specification may be determined using gel permeation chromatography (GPC) equipment obtained from Waters or similar equipment, and data processed with Waters Empower Software or similar software. The GPC equipment can be provided with a Waters separation module and a Waters refractive index detector (or any similar optional equipment). The GPC operating conditions can be such that a guard column, four Agilent PLgel columns (length 300×7.5 mm, particle size 5 μm, and pore size range 100 - 10,000 Å), and the column temperature can be about 40 °C. Unstabilized HPLC grade tetrahydrofuran (THF) can be used as the solvent at a flow rate of 1.0 mL / min. The GPC equipment can be calibrated with commercially available polystyrene (PS) standards having a narrow molecular weight distribution in the range of 500 - 380,000 g / mol. The calibration curve can be extrapolated for samples having a mass less than 500 g / mol. The sample and the PS standard can be dissolved in THF, prepared at a concentration of 0.1 - 0.5 wt%, and used without filtration. The GPC measurement is also described in U.S. Patent No. 5,266,223, which is incorporated herein by reference. The GPC method further provides molecular weight distribution information. See also, for example, W.W. Yau, J.J. Kirkland and D.D. Bly, "Modern Size Exclusion Liquid Chromatography", John Wiley and Sons, New York, 1979, which is incorporated herein by reference.

[0045] Poly(meth)acrylate copolymer: In another aspect, the second copolymer of the polymer blend for achieving good low-temperature pumpability comprises one or more poly(meth)acrylate copolymers, specifically copolymers derived from linear or branched alkyl esters of (meth)acrylic acid. Suitable alkyl (meth)acrylate reactants can have an alkyl chain length of 1 to 20 carbons. As used herein, "(meth)acrylate" refers to both methacrylate and / or acrylate monomers or monomer units (or mixtures). Typically, the poly(meth)acrylate polymer has a number average molecular weight of about 20,000 or more and a polydispersity index of about 3 or less, or 2 or less.

[0046] The poly(meth)acrylate copolymers suitable for the polymer additives herein can be prepared by any suitable conventional or controlled free radical polymerization techniques. Examples include conventional free radical polymerization (FRP), reversible addition-fragmentation chain transfer (RAFT), atom transfer radical polymerization (ATRP), and other controlled types of polymerization known in the art. The polymerization procedures are known to those skilled in the art and include, for example, the use of a common polymerization initiator (such as Vazo™ 67 (2,2'-azobis(2-methylbutyronitrile)), a chain transfer agent (such as dodecyl mercaptan) when using conventional FRP, or a RAFT agent (such as 4-cyano-4-[(dodecylsulfanylthiocarbonyl)sulfanyl]pentanoic acid) when using RAFT polymerization. Other initiators, chain transfer agents, RAFT agents, ATRP catalysts, and initiator systems can be used as known in the art depending on the selected polymerization method according to the requirements of a particular application.

[0047] In one approach, the copolymers herein include the reaction product in the form of a linear random polymer of a selected amount of long-chain alkyl (meth)acrylate monomer, intermediate-chain alkyl (meth)acrylate monomer, and short-chain alkyl (meth)acrylate monomer. In some approaches, the short-chain alkyl (meth)acrylate monomer (or monomer unit) has an alkyl chain length of 1 to 4 carbons, the intermediate alkyl (meth)acrylate monomer (or monomer unit) has an alkyl chain length of 6 to 16 carbons, and the long-chain alkyl (meth)acrylate monomer (or monomer unit) has an alkyl chain length of 16 to 20 carbons. These monomers and monomer units are further described below and include both linear alkyl groups and / or branched alkyl groups in the chain.

[0048] In one embodiment, the poly(meth)acrylate copolymer may include short-chain (meth)acrylate units derived from methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, and / or butyl (meth)acrylate. Preferably, the short-chain units are derived from methyl (meth)acrylate.

[0049] In another embodiment, the poly(meth)acrylate copolymer may also include intermediate-chain (meth)acrylate units derived from alkyl (meth)acrylate monomers having an alkyl group or total alkyl chain length (including any branching) of 6 to 16 carbons, preferably 12 to 16 carbons. Exemplary intermediate-chain alkyl (meth)acrylate may include a blend of (meth)acrylate monomers or monomer units having an alkyl chain length in the range of C12 - C16, specifically alkyl chains of 12, 14, and 16 carbons, with C12 alkyl (meth)acrylate being in the majority, and may be LMA or lauryl (meth)acrylate.

[0050] In yet another embodiment, the poly(meth)acrylate copolymer may also include long-chain alkyl (meth)acrylate units derived from alkyl (meth)acrylate monomers having an alkyl group or total alkyl chain length (including any branches) of 16 to 20 carbons, preferably 18 to 20 carbons. Exemplary medium-chain alkyl (meth)acrylates may include CEMA or cetyl-eicosyl (meth)acrylate, which may include (meth)acrylate monomers or blends of monomer units having an alkyl chain length in the range of C16-C20, specifically 16, 18, and 20 carbons. For example, a CEMA monomer blend or monomer unit blend may include a majority of C16 and C18 chains along with a minor amount of C20 chains.

[0051] The poly(meth)acrylate copolymers of this specification may also include other optional monomers and monomer units, such as hydroxyalkyl (meth)acrylates and / or various dispersant monomers and monomer units. The poly(meth)acrylate copolymers of this specification may optionally be functionalized with one or more dispersant monomers or monomer units. In one approach, the dispersant monomer or monomer unit may be a nitrogen-containing monomer or their units. Such monomers, when used, may impart a dispersant functional group to the polymer. In some approaches, the nitrogen-containing monomer may be a (meth)acrylic monomer such as methacrylate, methacrylamide, etc. In some approaches, the bond of the nitrogen-containing moiety to the acrylic moiety may be via a nitrogen atom or alternatively an oxygen atom, in which case the nitrogen of the monomer will be located elsewhere in the monomer. The nitrogen-containing monomer may be other than (meth)acrylic monomers such as vinyl-substituted nitrogen heterocyclic monomers and vinyl-substituted amines. The nitrogen-containing monomers include, for example, those in U.S. Patent No. 6,331,603. Other suitable dispersant monomers include, but are not limited to, dialkylaminoalkyl acrylates, dialkylaminoalkyl (meth)acrylates, dialkylaminoalkyl acrylamides, dialkylaminoalkyl methacrylamides, N-tertiary alkyl acrylamides, and N-tertiary alkyl methacrylamides, where the alkyl group or aminoalkyl group may independently contain 1 to 8 carbon atoms. For example, the dispersant monomer may be dimethylaminoethyl (meth)acrylate. The nitrogen-containing monomer may be, for example, t-butylacrylamide, dimethylaminopropyl (meth)acrylamide, dimethylaminoethyl methacrylamide, N-vinylpyrrolidone, N-vinylimidazole, or N-vinylcaprolactam.It may also be a (meth)acrylamide based on any of the aromatic amines disclosed in International Publication No. WO 2005 / 087821, including 4-phenylazoaniline, 4-aminodiphenylamine, 2-aminobenzimidazole, 3-nitroaniline, 4-(4-nitrophenylazo)aniline, N-(4-amino-5-methoxy-2-methyl-phenyl)-benzamide, N-(4-amino-2,5-dimethoxy-phenyl)-benzamide, N-(4-amino-2,5-diethoxy-phenyl)-benzamide, N-(4-amino-phenyl)-benzamide, and 4-amino-2-hydroxy-benzoic acid.

[0052] The PMA copolymers of the present disclosure are typically synthesized to have a number average molecular weight of 20,000 or more, and in other approaches, about 30,000 or less. Suitable ranges for the number average molecular weight include from about 10,000 to about 100,000, in other approaches, from about 20,000 to about 80,000, and in still other approaches, from about 30,000 to about 50,000. Such copolymers herein typically have a polydispersity index in the range of from about 1 to about 3, and in other approaches, from about 1.2 to about 3, and in still other approaches, from about 1.2 to about 2, and in still other approaches, from about 2 to about 3.

[0053] The poly(meth)acrylate copolymer may be prepared by any suitable conventional or controlled free radical polymerization technique. By way of example, conventional free radical polymerization (FRP), reversible addition fragmentation chain transfer (RAFT), atom transfer radical polymerization (ATRP), and other controlled types of polymerization known in the art may be mentioned. The polymerization procedures are known to those skilled in the art and include, for example, a general polymerization initiator (such as Vazo(trademark)67 (2,2'-azobis(2-methylbutyronitrile, etc.)), a chain transfer agent (such as dodecyl mercaptan, etc.) when using conventional FRP, or a RAFT agent (such as 4-cyano-4-[(dodecylsulfanylthiocarbonyl)sulfanyl]pentanoic acid, etc.) when using RAFT polymerization. Other initiators, chain transfer agents, RAFT agents, ATRP catalysts, and initiator systems can be used as known in the art depending on the selected polymerization method according to the requirements of a particular application.

[0054] Polymer blend: In another aspect, surprisingly, it has been discovered that only a blend of the modified styrene-maleic anhydride copolymer and the poly(meth)acrylate copolymer of the present specification achieves improved MRV performance when effective low-temperature performance cannot be achieved using any of the polymers individually. In one approach, the blend contains at least about 40 weight percent of the modified styrene-maleic anhydride copolymer, based on the total weight of the two copolymers in the blend, and in some approaches, up to about 60 weight percent of the modified styrene-maleic anhydride copolymer. The weight percent of the copolymer includes the active polymer and any solvent / diluent. The amount of the active polymer of the modified styrene-maleic anhydride copolymer ranges from about 30 to about 50 weight percent of the component. In other approaches, surprisingly, it has also been discovered that a specific ratio of the two copolymers in the blend achieves the desired result. For example, in some approaches, the ratio of the modified styrene-maleic anhydride copolymer to the poly(meth)acrylate copolymer effective to achieve good MRV performance is from about 1:2 to about 1:0.7.

[0055] Lubricating oil composition: The polymer additive blend of the two polymers described herein, in combination with one or more additional optional additives, may be combined with a major amount of base oil or a base oil of lubricating viscosity (as described below) to produce a lubricating oil composition having robust low-temperature viscosity characteristics including qualified MRV properties. In one approach, the lubricating oil composition herein may contain a polymer blend in an amount in the range of about 0.5 weight percent or more to about 1 weight percent or less, based on the total weight of the lubricant composition. In another approach, it may contain a polymer blend of about 0.5 to about 0.6 weight percent.

[0056] Base oil: The base oil used in the lubricating oil composition herein can be selected from any of the base oils in Groups I - V as specified in the American Petroleum Institute (API) Base Oil Interchangeability Guidelines. The five base oil groups are as follows:

[0057] [Table 1]

[0058] Groups I, II, and III are mineral oil process stocks. Group IV base oils contain true synthetic molecular species produced by the polymerization of olefinically unsaturated hydrocarbons. Many Group V base oils are also true synthetic products and may include diesters, polyol esters, polyalkylene glycols, alkylated aromatics, polyphosphate esters, polyvinyl ethers, and / or polyphenyl ethers, etc., or may be natural oils such as vegetable oils. Group III base oils are derived from mineral oils, but it should be noted that due to the rigorous treatment these fluids undergo, their physical properties become very similar to those of some true synthetic oils such as PAO. Thus, oils derived from Group III base oils can be referred to as synthetic fluids in the industry. Group II+ may include high-viscosity-index Group II.

[0059] The base oil used in the disclosed lubricating oil composition can be a mineral oil, an animal oil, a vegetable oil, a synthetic oil, a synthetic oil blend, or a mixture thereof. Suitable oils can be derived from hydrocracked, hydrogenated, hydrofinished, unrefined oils, refined oils, and re-refined oils, and mixtures thereof.

[0060] Unrefined oils are those derived from natural, mineral, or synthetic sources that have undergone little or no further refining treatment. Refined oils are similar to unrefined oils except that they have been treated in one or more refining steps that can result in the improvement of one or more properties. Examples of suitable refining techniques are solvent extraction, secondary distillation, acid or base extraction, filtration, percolation, etc. Oils refined to a quality suitable for consumption may or may not be useful. Edible oils may also be referred to as white oils. In some embodiments, the lubricating oil composition does not contain edible oil or white oil.

[0061] Re-refined oils are also known as recycled oils or reprocessed oils. These oils are obtained in a manner similar to refined oils using the same or similar processes. In many cases, these oils are further treated by techniques aimed at removing used additives and oil degradation products.

[0062] Mineral oils can include oils obtained by drilling, or from plants and animals, or any mixture thereof. For example, such oils can include castor oil, lard oil, olive oil, peanut oil, corn oil, soybean oil, and linseed oil, and mineral lubricating oils, such as liquid petroleum, and paraffinic, naphthenic, or mixed paraffinic-naphthenic type solvent-treated or acid-treated mineral lubricating oils, but are not limited thereto. Such oils can be partially or fully hydrogenated if desired. Oils derived from coal or shale can also be useful.

[0063] Useful synthetic lubricating oils include hydrocarbon oils such as polymerized, oligomerized, or interpolymerized olefins (e.g., polybutylene, polypropylene, propylene isobutylene copolymer); poly(1 - hexene), poly(1 - octene), trimers or oligomers of 1 - decene such as poly(1 - decene) (such materials are often referred to as α - olefins), and mixtures thereof; alkyl - benzenes (e.g., dodecylbenzene, tetradecylbenzene, dinonylbenzene, di - (2 - ethylhexyl) - benzene); polyphenyls (e.g., biphenyl, terphenyl, alkylated polyphenyls); diphenylalkanes, alkylated diphenylalkanes, alkylated diphenyl ethers and alkylated diphenyl sulfides, and their derivatives, analogs, and homologs, or mixtures thereof. Polyalphaolefins are typically hydrogenated materials.

[0064] Other synthetic lubricating oils include polyol esters, diesters, liquid esters of phosphorus - containing acids (e.g., tricresyl phosphate, trioctyl phosphate, and diethyl ester of decanephosphonic acid), or polymerized tetrahydrofuran. Synthetic oils can be produced by the Fischer - Tropsch reaction and can typically be hydrogen - isomerized Fischer - Tropsch hydrocarbons or waxes. In one embodiment, the oil can be prepared by a Fischer - Tropsch gas - liquid synthesis procedure, as well as other gas - liquid oils.

[0065] The major amount of base oil contained in the lubricating composition can be selected from the group consisting of Group I, Group II, Group III, Group IV, Group V, and combinations of two or more of the foregoing, and the major amount of base oil is other than the base oil resulting from the provision of additive components or viscosity index improvers in the composition. In another embodiment, the major amount of base oil contained in the lubricating composition can be selected from the group consisting of Group II, Group III, Group IV, Group V, and combinations of two or more of the foregoing, and the major amount of base oil is other than the base oil resulting from the provision of additive components or viscosity index improvers in the composition.

[0066] The amount of oil having a lubricating viscosity that is present can be the remainder after subtracting the total amount of viscosity index improver(s) and / or pour point depressant(s) and / or other performance additives including top treatment additives from 100% by weight. For example, the oil having a lubricating viscosity that can be present in the final fluid can be a "major amount", e.g., greater than about 50% by weight, greater than about 60% by weight, greater than about 70% by weight, greater than about 80% by weight, greater than about 85% by weight, or greater than about 90% by weight.

[0067] Optional additives: The engine oil or lubricating oil composition of the present specification may also optionally contain some optional additives as necessary to meet the performance specifications. Those optional additives are described in the following paragraphs.

[0068] Antioxidants: The lubricating oil composition of the present specification may also optionally contain one or more antioxidants. Antioxidant compounds are known and include, for example, phenates, phenate sulfides, sulfurized olefins, phosphosulfurized terpenes, sulfurized esters, aromatic amines, alkylated diphenylamines (e.g., nonyldiphenylamine, di-nonyldiphenylamine, octyldiphenylamine, di-octyldiphenylamine), phenyl-alpha-naphthylamine, alkylated phenyl-alpha-naphthylamine, hindered non-aromatic amines, phenols, hindered phenols, oil-soluble molybdenum compounds, polymeric antioxidants, or mixtures thereof. The antioxidant compounds can be used alone or in combination.

[0069] The hindered phenol antioxidant may contain a secondary butyl group and / or a tertiary butyl group as a steric hindrance group. The phenol group may be further substituted with a hydrocarbyl group and / or a crosslinking group bonded to a second aromatic group. Examples of suitable hindered phenol antioxidants include 2,6-di-tert-butylphenol, 4-methyl-2,6-di-tert-butylphenol, 4-ethyl-2,6-di-tert-butylphenol, 4-propyl-2,6-di-tert-butylphenol or 4-butyl-2,6-di-tert-butylphenol, or 4-dodecyl-2,6-di-tert-butylphenol. In one embodiment, the hindered phenol antioxidant may be an ester, for example, it may contain Irganox™ L-135 available from BASF or an adduct product derived from 2,6-di-tert-butylphenol and an alkyl acrylate, and the alkyl group may contain from about 1 to about 18, or from about 2 to about 12, or from about 2 to about 8, or from about 2 to about 6, or about 4 carbon atoms. Another commercially available hindered phenol antioxidant may be an ester and may include Ethanox™ 4716 available from Albemarle Corporation.

[0070] Useful antioxidants may include diarylamines and high molecular weight phenols. In certain embodiments, the lubricating oil composition may contain a mixture of a diarylamine and a high molecular weight phenol, and each antioxidant may be present in an amount sufficient to provide up to about 5 wt% based on the final weight of the lubricating oil composition. In one embodiment, the antioxidant may be a mixture of about 0.3 to about 1.5 wt% diarylamine and about 0.4 to about 2.5 wt% high molecular weight phenol based on the final weight of the present lubricating oil composition.

[0071] Examples of suitable olefins that may be sulfided to form a sulfurized olefin include propylene, butylene, isobutylene, polyisobutylene, pentene, hexene, heptene, octene, nonene, decene, undecene, dodecene, tridecene, tetradecene, pentadecene, hexadecene, heptadecene, octadecene, nonadecene, eicosene, or mixtures thereof. In one embodiment, hexadecene, heptadecene, octadecene, nonadecene, eicosene, or mixtures thereof, and their dimers, trimers, and tetramers are particularly useful olefins. Alternatively, the olefin may be a Diels - Alder adduct of a diene such as 1,3 - butadiene and an unsaturated ester such as butyl acrylate.

[0072] Another class of sulfurized olefins includes sulfurized fatty acids and their esters. Fatty acids are often obtained from vegetable or animal oils and typically contain from about 4 to about 22 carbon atoms. Examples of suitable fatty acids and their esters include triglycerides, oleic acid, linoleic acid, palmitoleic acid, or mixtures thereof. Often, fatty acids are obtained from lard oil, tall oil, peanut oil, soybean oil, cottonseed oil, sunflower seed oil, or mixtures thereof. The fatty acid and / or ester may be mixed with an olefin such as an α - olefin.

[0073] In another alternative embodiment, the antioxidant composition also contains a molybdenum - containing antioxidant in addition to the phenolic and / or amine antioxidants described above. When a combination of these three antioxidants is used, preferably, the ratios of phenol, amine, and molybdenum - containing are (0 - 2):(0 - 2):(0 - 1).

[0074] One or more antioxidants may be present in the lubricating oil composition in the range of about 0 wt% to about 20 wt%, or about 0.1 wt% to about 10 wt%, or about 1 wt% to about 5 wt%.

[0075] Anti-wear agent: The lubricating oil composition of the present specification may also optionally contain one or more anti-wear agents. Examples of suitable anti-wear agents include metal thiophosphates, metal dialkyldithiophosphates, phosphoric acid esters or their salts, phosphate esters, phosphites, phosphorus-containing carboxylic acid esters, ethers, or amides, sulfurized olefins, thiocarbamate esters, alkylene-bonded thiocarbamates, and thiocarbamate-containing compounds including bis(S-alkyldithiocarbamyl) disulfide, and mixtures thereof, but are not limited thereto. A suitable anti-wear agent may be molybdenum dithiocarbamate. Phosphorus-containing anti-wear agents are described in more detail in European Patent No. 612839. The metal in the dialkyldithiophosphate salt may be an alkali metal, alkaline earth metal, aluminum, lead, tin, molybdenum, manganese, nickel, copper, titanium, or zinc. A useful anti-wear agent may be zinc dialkyldithiophosphate.

[0076] Further examples of suitable anti-wear agents include titanium compounds, tartrates, tartrimides, oil-soluble amine salts of phosphorus compounds, sulfurized olefins, phosphites (e.g., dibutyl phosphite), phosphonates, thiocarbamate-containing compounds, such as thiocarbamate esters, thiocarbamate amides, thiocarbamic acid ethers, alkylene-bonded thiocarbamates, and bis(S-alkyldithiocarbamyl) disulfide. The tartrate or tartrimide may contain alkyl-ester groups, and the total number of carbon atoms on the alkyl group may be at least 8. In one embodiment, the anti-wear agent may include citrate.

[0077] The anti-wear agent may be present in the range of about 0 wt% to about 15 wt%, or about 0.01 wt% to about 10 wt%, or about 0.05 wt% to about 5 wt%, or about 0.1 wt% to about 3 wt% of the lubricating oil composition.

[0078] Boron-containing compound: The lubricating oil composition of the present specification may optionally contain one or more boron-containing compounds. Examples of boron-containing compounds include boron-containing dispersants such as boric acid esters, fatty amine borates, boron-containing epoxides, boronated detergents, and boronated succinimide dispersants, as disclosed in U.S. Patent No. 5,883,057. The boron-containing compound, if present, can be used in an amount sufficient to provide up to about 8% by weight, about 0.01% to about 7% by weight, about 0.05% to about 5% by weight, or about 0.1% to about 3% by weight of the lubricating oil composition.

[0079] Detergent: The lubricating oil composition may optionally further comprise one or more neutral detergents, low-base detergents, or overbased detergents, and mixtures thereof. Suitable detergent substrates include phenates, sulfur-containing phenates, sulfonates, calixarates, salixarates, salicylates, carboxylic acids, phosphoric acids, mono- and / or dithiophosphoric acids, alkylphenols, sulfur-bonded alkylphenol compounds, or methylene-bridged phenols. Suitable detergents and methods for their preparation are described in detail in a number of patent publications, including US 7,732,390 and the references cited therein.

[0080] The detergent base may be salted with an alkali metal or alkaline earth metal such as, but not limited to, calcium, magnesium, potassium, sodium, lithium, barium, or a mixture thereof. In some embodiments, the detergent is barium-free. In some embodiments, the detergent may contain trace amounts of other metals such as magnesium or calcium in an amount of 50 ppm or less, 40 ppm or less, 30 ppm or less, 20 ppm or less, or 10 ppm or less. Suitable detergents may include alkali metal or alkaline earth metal salts of petroleum sulfonic acids and long-chain mono- or dialkylaryl sulfonic acids where the aryl groups are benzyl, tolyl, and xylyl. Examples of suitable detergents include calcium phenate, calcium sulfur-containing phenate, calcium sulfonate, calcium calyxarate, calcium salicylate, calcium carboxylic acid, calcium phosphate, calcium mono- and / or dithiophosphate, calcium alkylphenol, calcium sulfur-bonded alkylphenol compound, calcium methylene-bridged phenol, magnesium phenate, magnesium sulfur-containing phenate, magnesium sulfonate, magnesium calyxarate, magnesium salicylate, magnesium carboxylic acid, magnesium phosphate, magnesium mono- and / or dithiophosphate, magnesium alkylphenol, magnesium sulfur-bonded alkylphenol compound, magnesium methylene-bridged phenol, sodium phenate, sodium sulfur-containing phenate, sodium sulfonate, sodium calyxarate, sodium salicylate, sodium carboxylic acid, sodium phosphate, sodium mono- and / or dithiophosphate, sodium alkylphenol, sodium sulfur-bonded alkylphenol compound, or sodium methylene-bridged phenol, but are not limited thereto.

[0081] Overbased detergent additives are well known in the art and can be alkali or alkaline earth metal overbased detergent additives. Such detergent additives can be prepared by reacting a metal oxide or metal hydroxide with a substrate and carbon dioxide gas. The substrate is typically an acid, such as an aliphatic substituted sulfonic acid, an aliphatic substituted carboxylic acid, or an aliphatic substituted phenol.

[0082] The term "overbased" relates to metal salts such as sulfonates, carboxylates, and phenates where the amount of metal present exceeds the stoichiometric amount. Such salts can have a conversion level greater than 100% (i.e., they can contain more than 100% of the theoretical amount of metal required to convert the acid to its "normal salt", "neutral salt"). In many cases, the expression "metal ratio", abbreviated as MR, is used to indicate the ratio of the total chemical equivalents of metal in the overbased salt to the chemical equivalents of metal in the neutral salt according to known chemical reactivity and stoichiometry. The metal ratio is 1 for the normal or neutral salt, but MR is greater than 1 for the overbased salt. They are generally referred to as overbased, highly basic, or superbasic salts and can be salts of organic sulfuric acids, carboxylic acids, or phenols.

[0083] The overbased detergent of the lubricating oil composition may have a total base number (TBN) of about 200 mg KOH / gram or more, or as a further example, about 250 mg KOH / gram or more, or about 350 mg KOH / gram or more, or about 375 mg KOH / gram or more, or about 400 mg KOH / gram or more.

[0084] Examples of suitable overbased detergents include, but are not limited to, overbased calcium phenate, overbased calcium sulfur-containing phenate, overbased calcium sulfonate, overbased calcium calixarate, overbased calcium salixarate, overbased calcium salicylate, overbased calcium carboxylate, overbased calcium phosphate, overbased calcium mono- and / or di-thiophosphate, overbased calcium alkylphenol, overbased calcium sulfur-bonded alkylphenol compound, overbased calcium methylene-bridged phenol, overbased magnesium phenate, overbased magnesium sulfur-containing phenate, overbased magnesium sulfonate, overbased magnesium calixarate, overbased magnesium salixarate, overbased magnesium salicylate, overbased magnesium carboxylate, overbased magnesium phosphate, overbased magnesium mono- and / or di-thiophosphate, overbased magnesium alkylphenol, overbased magnesium sulfur-bonded alkylphenol compound, or overbased magnesium methylene-bridged phenol.

[0085] Overbased calcium phenate detergents have a total base number of at least about 150 mg KOH / g, at least about 225 mg KOH / g, at least about 225 mg KOH / g to about 400 mg KOH / g, at least about 225 mg KOH / g to about 350 mg KOH / g, or about 230 mg KOH / g to about 350 mg KOH / g when measured by the method of ASTM D-2896. When such a detergent composition is formed in an inert diluent, such as a process oil, usually a mineral oil, the total base number reflects the basicity of the overall composition including the diluent and any other substances (e.g., promoters, etc.) that may be included in the detergent composition.

[0086] The overbased detergent can have a metal-to-substrate ratio of from 1.1:1, or from 2:1, or from 4:1, or from 5:1, or from 7:1, or from 10:1. In some embodiments, the detergent is effective in reducing or preventing rust in the engine. The detergent may be present at from about 0 wt% to about 10 wt%, or from about 0.1 wt% to about 8 wt%, or from about 1 wt% to about 4 wt%, or greater than about 4 wt% to about 8 wt%.

[0087] Dispersant: The lubricating oil composition may optionally further comprise one or more dispersants or mixtures thereof. The dispersant does not contain a metal that forms ash before being mixed into the lubricating oil composition and typically does not contribute to ash when added to the lubricant, and is thus often referred to as an ashless type dispersant. The ashless type dispersant is characterized in that the polar group is bonded to a relatively high molecular weight hydrocarbon chain. Typical ashless dispersants include N-substituted long chain alkenyl succinimides. Examples of N-substituted long chain alkenyl succinimides include polyisobutylene succinimides in which the number average molecular weight of the polyisobutylene substituent ranges from about 350 to about 50,000, or up to about 5,000, or up to about 3,000 as measured by GPC. The succinimide dispersant and its preparation method are disclosed, for example, in U.S. Patent No. 7897696 or U.S. Patent No. 4234435. The polyolefin can be prepared from polymerizable monomers containing from about 2 to about 16 carbon atoms, or from about 2 to about 8 carbon atoms, or from about 2 to about 6 carbon atoms. The succinimide dispersant is typically an imide formed from a polyamine, typically poly(ethyleneamine).

[0088] Preferred amines are selected from polyamines and hydroxyamines. Examples of polyamines that can be used include higher homologues such as diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), and pentaethyleneaminehexamine (PEHA), but are not limited thereto.

[0089] Suitable heavy polyamines include small amounts of lower polyamine oligomers such as TEPA and PEHA (pentaethylenehexamine), but mainly mixtures of polyalkylene-polyamines containing six or more nitrogen atoms, two or more primary amines per molecule, and oligomers with a broader range of branching than conventional polyamine mixtures. The heavy polyamines preferably contain polyamine oligomers containing seven or more nitrogens per molecule and having two or more primary amines per molecule. The heavy polyamines contain more than 28 wt% (e.g., > 32 wt%) total nitrogen and 120 - 160 grams of equivalent primary amine groups per equivalent.

[0090] Suitable polyamines are generally known as PAM, contain mixtures of TEPA and pentaethylenehexamine (PEHA) as the major part of the polyamine, and usually contain less than about 80% ethylenediamine.

[0091] Typically, PAM has 8.7 - 8.9 milliequivalents of primary amine per gram (115 - 112 grams of equivalent per equivalent of primary amine) and a total nitrogen content of about 33 - 34 wt%. A heavier cut of PAM oligomers that contains substantially no TEPA and only very small amounts of PEHA but mainly contains six or more nitrogens and oligomers with a broader range of branching may produce a dispersant with improved dispersibility.

[0092] In certain embodiments, the disclosure further includes at least one polyisobutylene succinimide dispersant derived from polyisobutylene having a number average molecular weight in the range of about 350 to about 50,000, or ~ about 5000, or ~ about 3000 as determined by GPC. The polyisobutylene succinimide can be used alone or in combination with other dispersants.

[0093] In some embodiments, polyisobutylene, when included, may have a terminal double bond content of more than 50 mol%, more than 60 mol%, more than 70 mol%, more than 80 mol%, or more than 90 mol%. Such PIB is also referred to as high-reactivity PIB ("HR-PIB"). HR-PIB having a number average molecular weight in the range of about 800 to about 5000 as determined by GPC is suitable for use in embodiments of the present disclosure. Conventional PIB typically has a terminal double bond content of less than 50 mol%, less than 40 mol%, less than 30 mol%, less than 20 mol%, or less than 10 mol%.

[0094] HR-PIB having a number average molecular weight in the range of about 900 to about 3000 may also be suitable when determined by GPC. Such HR-PIB is commercially available or can be synthesized by polymerization of isobutene in the presence of a non-chlorinated catalyst such as boron trifluoride as described in U.S. Patent No. 4,152,499 to Boerzel, et al. and U.S. Patent No. 5,739,355 to Gateau, et al. When used in the above thermo-ene reaction, HR-PIB can result in a higher conversion during the reaction and a lower amount of precipitate formation due to improved reactivity. A suitable method is described in U.S. Patent No. 7897696.

[0095] In one embodiment, the present disclosure further includes at least one dispersant derived from polyisobutylene succinic anhydride ("PIBSA"). PIBSA may have an average of about 1.0 to about 2.0 succinic acid moieties per polymer.

[0096] The active % of alkenyl or alkyl succinic anhydride can be determined using chromatographic techniques. This method is described in column 5 or column 6 of U.S. Patent No. 5334321.

[0097] The conversion rate of the polyolefin is calculated from the active % using the equations described in columns 5 and 6 of U.S. Patent No. 5334321.

[0098] Unless otherwise specified, all percentages are by weight and all molecular weights are number average molecular weights determined by gel permeation chromatography (GPC) using commercially available polystyrene standards (having a number average molecular weight of 180 to about 18,000 as a calibration standard).

[0099] In one embodiment, the dispersant may be derived from polyalphaolefin (PAO) succinic anhydride. In one embodiment, the dispersant may be derived from an olefin maleic anhydride copolymer. By way of example, the dispersant may be described as polyPIBSA. In certain embodiments, the dispersant may be derived from an anhydride grafted onto an ethylene-propylene copolymer.

[0100] Suitable types of nitrogen-containing dispersants can be derived from olefin copolymers (OCPs), more specifically, ethylene-propylene dispersants that can be grafted with maleic anhydride. A more complete list of nitrogen-containing compounds that can react with functionalized OCPs is described in U.S. Pat. Nos. 7,485,603, 7,786,057, 7,253,231, 6,107,257, and 5,075,383 and / or is commercially available.

[0101] Alternatively, the hydrocarbyl portion of the hydrocarbyl-dicarboxylic acid or the anhydride of component A) can be derived from an ethylene-alpha olefin copolymer. These copolymers contain a plurality of ethylene units and a plurality of one or more C3-C 10 alpha-olefin units. The C3-C 10 alpha-olefin units may include propylene units.

[0102] The ethylene-alpha olefin copolymer typically has a number average molecular weight of less than 5,000 g / mol as measured by GPC using polystyrene as a calibration standard, or the number average molecular weight of the copolymer may be less than 4,000 g / mol, or less than 3,500 g / mol, or less than 3,000 g / mol, or less than 2,500 g / mol, or less than 2,000 g / mol, or less than 1,500 g / mol, or less than 1,000 g / mol. In some embodiments, the number average molecular weight of the copolymer may be from 800 to 3,000 g / mol.

[0103] The ethylene content of the ethylene-alpha olefin copolymer may be less than 80 mol%, less than 70 mol%, or less than 65 mol%, or less than 60 mol%, or less than 55 mol%, or less than 50 mol%, or less than 45 mol%, or less than 40 mol%. The ethylene content of the copolymer may be at least 10 mol% and less than 80 mol%, or at least 20 mol% and less than 70 mol%, or at least 30 mol% and less than 65 mol%, or at least 40 mol% and less than 60 mol%.

[0104] The C3-C 10 alpha-olefin content of the ethylene-alpha olefin copolymer may be at least 20 mol%, or at least 30 mol%, or at least 35 mol%, or at least 40 mol%, or at least 45 mol%, or at least 50 mol%, or at least 55 mol%, or at least 60 mol%.

[0105] In some embodiments, at least 70 mol% of the molecules of the ethylene-alpha olefin copolymer may have an unsaturated group, and at least 70 mol% of the unsaturated groups may be located at a terminal vinylidene group or a trisubstituted isomer of the terminal vinylidene group, or at least 75 mol% of the copolymer may terminate with a terminal vinylidene group or a trisubstituted isomer of the terminal vinylidene group, or at least 80 mol% of the copolymer may terminate with a terminal vinylidene group or a trisubstituted isomer of the terminal vinylidene group, or at least 80 mol% of the copolymer may terminate with a terminal vinylidene group or a trisubstituted isomer of the terminal vinylidene group, or at least 85 mol% of the copolymer may terminate with a terminal vinylidene group or a trisubstituted isomer of the terminal vinylidene group, or at least 90 mol% of the copolymer may terminate with a terminal vinylidene group or a trisubstituted isomer of the terminal vinylidene group, or at least 95 mol% of the copolymer may terminate with a terminal vinylidene group or a trisubstituted isomer of the terminal vinylidene group. The terminal vinylidene and the trisubstituted isomers of the terminal vinylidene of the copolymer have one or more of the following structural formulas (A) to (C),

[0106] [Chemical Formula] wherein R represents a C1-C8 alkyl group,

[0107] [Chemical Formula] indicates that the bond is bonded to the remaining part of the copolymer.

[0108] The ethylene-alpha olefin copolymer 13 may have an average ethylene unit run length (n C2 ) of less than 2.8 when measured by 13C NMR spectroscopy, and also satisfies the relationship shown by the following formula: [Formula] wherein, EEE = (x C2 ) 3 , EEA = 2(x C2 ) 2 (1 - x C2 )、 AEA = x C2 (1 - x C2 ) 2 wherein x C2 is 1 the mole fraction of ethylene incorporated into the polymer when measured by H-NMR spectroscopy, E represents an ethylene unit, and A represents an alpha-olefin unit. The copolymer may have an average ethylene unit run length of less than 2.6, or less than 2.4, or less than 2.2, or less than 2. The average ethylene run length n c2 may also satisfy the relationship represented by the following equation. n C2,Actual < n C2,Statistical

[0109] The crossover temperature of the ethylene-alpha olefin copolymer may be -20 °C or lower, or -25 °C or lower, or -30 °C or lower, or -35 °C or lower, or -40 °C or lower. The copolymer may have a polydispersity index of 4 or lower, or 3 or lower, or 2 or lower. Less than 20% of the unit triads in the copolymer may be ethylene-ethylene-ethylene triads, or less than 10% of the unit triads in the copolymer may be ethylene-ethylene-ethylene triads, or less than 5% of the unit triads in the copolymer may be ethylene-ethylene-ethylene triads. Further details of the ethylene-alpha olefin copolymer and the dispersant made therefrom can be found in PCT / US18 / 37116 filed with the United States Receiving Office, the disclosure of which is hereby incorporated herein by reference in its entirety.

[0110] One type of suitable dispersant can be a Mannich base. A Mannich base is a material formed by the condensation of a higher molecular weight alkyl-substituted phenol, a polyalkylene polyamine, and an aldehyde such as formaldehyde. Mannich bases are described in more detail in U.S. Patent No. 3,634,515.

[0111] Suitable types of dispersants can be high molecular weight esters or semi-ester amides. Suitable dispersants can also be post-treated by conventional methods by reaction with any of various agents. Among these are boron, urea, thiourea, dimercaptothiadiazole, carbon disulfide, aldehydes, ketones, carboxylic acids, hydrocarbon-substituted succinic anhydrides, maleic anhydride, nitriles, epoxides, carbonates, cyclic carbonates, hindered phenolic esters, and phosphorus compounds. U.S. Patent No. 7,645,726, U.S. Patent No. 7,214,649, and U.S. Patent No. 8,048,831 are hereby incorporated by reference in their entirety.

[0112] In addition to the post-treatment with carbonate and boric acid, the compounds may each be post-treated or further post-treated by various post-treatments designed to improve or impart different properties. Such post-treatments include those summarized in columns 27-29 of U.S. Patent No. 5,241,003, which is incorporated herein by reference. Such treatments include inorganic phosphoric acid or anhydrides (e.g., U.S. Patents Nos. 3,403,102 and 4,648,980), organic phosphorus compounds (e.g., U.S. Patent No. 3,502,677), phosphorus pentasulfide, boron compounds as already described above (e.g., U.S. Patents Nos. 3,178,663 and 4,652,387), carboxylic acids, polycarboxylic acids, anhydrides, and / or acid halides (e.g., U.S. Patents Nos. 3,708,522 and 4,948,386), epoxides polyepoxy esters or thioepoxides (e.g., U.S. Patents Nos. 3,859,318 and 5,026,495), aldehydes or ketones (e.g., U.S. Patent No. 3,458,530), carbon disulfide (e.g., U.S. Patent No. 3,256,185), glycidol (e.g., U.S. Patent No. 4,617,137), urea, thiourea, or guanidine (e.g., U.S. Patents Nos. 3,312,619, 3,865,813, and British Patent No. GB1,065,595), organic sulfonic acids (e.g., U.S. Patent No. 3,189,544 and British Patent No. GB2,140,811), alkenyl cyanides (e.g., U.S. Patents Nos. 3,278,550 and 3,366,569), diketene (e.g., U.S. Patent No. 3,546,243), diisocyanates (e.g., U.S. Patent No. 3,573,205), alkanesultones (e.g., U.S. Patent No. 3,749,695), 1,3-dicarbonyl compounds (e.g., U.S. Patent No. 4,579,675), sulfates of alkoxylated alcohols or phenols (e.g., U.S. Patent No. 3,954,639), cyclic lactones (e.g., U.S. Patents Nos. 4,617,138, 4,645,515, 4,668,246, 4,963,275, and 4,971,711), cyclic carbonates or thiocarbonates, linear monocarbonates or polycarbonates, or chloroformates (e.g., U.S. Patents Nos. 4,612,132, 4,647,390, 4,648,(U.S. Patent Nos. 4,670,170 and 886), nitrogen-containing carboxylic acids (e.g., U.S. Patent No. 4,971,598 and British Patent No. GB2,140,811), hydroxy-protected chlorodicarbonyl oxy compounds (e.g., U.S. Patent No. 4,614,522), lactams, thiolactams, thiolactones, or ditractones (e.g., U.S. Patent Nos. 4,614,603 and 4,666,460), cyclic carbonates or thiocarbonates, linear monocarbonates or polycarbonates, or chloroformates (e.g., U.S. Patent Nos. 4,612,132, 4,647,390, 4,646,860, and 4,670,170), nitrogen-containing carboxylic acids (e.g., U.S. Patent No. 4,971,598 and British Patent No. GB2,440,811), hydroxy-protected chlorodicarbonyl oxy compounds (e.g., U.S. Patent No. 4,614,522), lactams, thiolactams, thiolactones, or dithiolactones (e.g., U.S. Patent Nos. 4,614,603 and 4,666,460), cyclic carbamates, cyclic thiocarbamates, or cyclic dithiocarbamates (e.g., U.S. Patent Nos. 4,663,062 and 4,666,459), hydroxy aliphatic carboxylic acids (e.g., U.S. Patent Nos. 4,482,464, 4,521,318, 4,713,189), oxidizing agents (e.g., U.S. Patent No. 4,379,064), combinations of phosphorus pentasulfide and polyalkylene polyamines (e.g., U.S. Patent No. 3,185,647), combinations of carboxylic acids or aldehydes or ketones with sulfur or sulfur chloride (e.g., U.S. Patent Nos. 3,390,086, 3,470,098), combinations of hydrazine and carbon disulfide (e.g., U.S. Patent No. 3,519,564), combinations of aldehydes and phenols (e.g., U.S. Patent Nos. 3,649,229, 5,030,249, 5,039,307), combinations of aldehydes and O-diesters of dithiophosphoric acid (e.g., U.S. Patent No. 3,865,740), combinations of hydroxy aliphatic carboxylic acids and boric acid (e.g., U.S. Patent No. 4,554,086), combinations of hydroxy aliphatic carboxylic acids with subsequent formaldehyde and phenol (e.g., U.S. Patent No. 4,636,Combinations of hydroxy aliphatic carboxylic acids and subsequent aliphatic dicarboxylic acids (e.g., U.S. Patent No. 4,663,064), combinations of formaldehyde, phenol, and subsequent glycolic acid (e.g., U.S. Patent No. 4,699,724), combinations of hydroxy aliphatic carboxylic acids or oxalic acid and subsequent diisocyanates (e.g., U.S. Patent No. 4,713,191), combinations of inorganic acids or anhydrides of phosphorus or their partial or total sulfur analogs and boron compounds (e.g., U.S. Patent No. 4,857,214), combinations of organic diacids, subsequent unsaturated fatty acids, subsequent nitroso aromatic amines, optionally followed by boron compounds, and subsequent glycolating agents (e.g., U.S. Patent No. 4,973,412), combinations of aldehydes and triazoles (e.g., U.S. Patent No. 4,963,278), combinations of aldehydes, triazoles, and subsequent boron compounds (e.g., U.S. Patent No. 4,981,492), combinations of cyclic lactones and boron compounds (e.g., U.S. Patent No. 4,963,275 and 4,971,711) are included. Here, the patents mentioned above are incorporated in their entirety.,

[0113] The TBN of a suitable dispersant may be a dispersant of about 10 to about 65 mg KOH / g on an oil-free basis, comparable to about 5 to about 30 TBN when measured on a dispersant sample containing about 50% diluted oil. TBN is measured by the method of ASTM D2896.,

[0114] The dispersant, when present, can be used in an amount sufficient to provide up to about 20 weight percent based on the final weight of the lubricating oil composition. Another amount of dispersant that can be used can be about 0.1 weight percent to about 15 weight percent, or about 0.1 weight percent to about 10 weight percent, or about 3 weight percent to about 10 weight percent, or about 1 weight percent to 6 weight percent, or about 7 weight percent to about 12 weight percent, based on the final weight of the present lubricating oil composition. In some embodiments, the lubricating oil composition utilizes a mixed dispersant system. Mixtures of a single type or two or more types of dispersants in any desired ratio can be used.,

[0115] Extreme Pressure Agents: The lubricating oil compositions herein may also optionally contain one or more extreme pressure agents. Extreme pressure (EP) agents that are soluble in oil include sulfur and chlorosulfur-containing EP agents, chlorinated hydrocarbon EP agents, and phosphorus EP agents. Examples of such EP agents include chlorinated waxes, organic sulfides and polysulfides such as dibenzyl disulfide, bis(chlorobenzyl) disulfide, dibutyl tetrasulfide, sulfurized methyl ester of oleic acid, sulfurized alkylphenols, sulfurized dipentenes, sulfurized terpenes, and sulfurized Diels-Alder adducts, phosphorus sulfurized hydrocarbons such as the reaction products of phosphorus sulfide with turpentine or methyl oleate, dihydrocarbyl and trihydrocarbyl phosphites, for example, phosphate esters such as dibutyl phosphite, diheptyl phosphite, dicyclohexyl phosphite, pentyl phenyl phosphite, dipentyl phenyl phosphite, tridecyl phosphite, distearyl phosphite, and polypropylene substituted phenyl phosphites, metal thiocarbamates such as zinc dioctyldithiocarbamate and barium heptylphenol diate, amine salts of alkyl and dialkyl phosphoric acids including, for example, the amine salt of the reaction product of a dialkyl dithiophosphoric acid with propylene oxide, and mixtures thereof.

[0116] Friction modifiers: The lubricating oil compositions herein may also optionally contain one or more friction modifiers. Suitable friction modifiers may include metal-containing and metal-free friction modifiers, and may include, but are not limited to, imidazolines, amides, amines, succinimides, alkoxylated amines, alkoxylated ether amines, amine oxides, amidoamines, nitriles, betaines, quaternary amines, imines, amine salts, aminoguanidines, alkanolamides, phosphonates, metal-containing compounds, glycerol esters, sulfurized fatty compounds and olefins, sunflower oil, other naturally occurring vegetable or animal oils, dicarboxylic acid esters, esters or partial esters of polyols and one or more aliphatic or aromatic carboxylic acids, and the like.

[0117] Suitable friction modifiers may contain a hydrocarbyl group selected from linear, branched, or aromatic hydrocarbyl groups, or mixtures thereof, and may be saturated or unsaturated. The hydrocarbyl group may be composed of carbon and hydrogen or heteroatoms such as sulfur or oxygen. The hydrocarbyl group may range from about 12 to about 25 carbon atoms. In some embodiments, the friction modifier can be a long-chain fatty acid ester. In another embodiment, the long-chain fatty acid ester can be a monoester, or diester, or (tri)glyceride. The friction modifier may be a long-chain fatty amide, long-chain fatty ester, long-chain fatty epoxide derivative, or long-chain imidazoline.

[0118] Other suitable friction modifiers include organic, ashless (metal-free), nitrogen-free organic friction modifiers. Such friction modifiers can include esters formed by reacting carboxylic acids and anhydrides with alkanols and generally contain polar end groups (e.g., carboxyl or hydroxyl) covalently bonded to a lipophilic hydrocarbon chain. An example of an organic ashless nitrogen-free friction modifier is glycerol monooleate (GMO), which can contain mono-, di-, and tri-esters of oleic acid and is generally known as such. Other suitable friction modifiers are described in U.S. Patent No. 6,723,685, which is hereby incorporated by reference in its entirety.

[0119] Examples of amine-based friction modifiers include amines or polyamines. Such compounds can have a hydrocarbyl group that is either linear, saturated or unsaturated, or mixtures thereof, and may contain from about 12 to about 25 carbon atoms. Further examples of suitable friction modifiers include alkoxylated amines and alkoxylated ether amines. Such compounds can have a hydrocarbyl group that is either linear, saturated or unsaturated, or mixtures thereof. They may contain from about 12 to about 25 carbon atoms. Examples include ethoxylated amines and ethoxylated ether amines.

[0120] Amines and amides can be used by themselves or in the form of adducts or reaction products with boron compounds such as boron oxide, boron halides, metaborates, boric acid or mono-, di-, or tri-alkyl borates. Other suitable friction modifiers are described in U.S. Patent No. 6,300,291, which is hereby incorporated by reference in its entirety.

[0121] The friction modifier may optionally be present in an amount ranging from about 0 wt% to about 10 wt%, or from about 0.01 wt% to about 8 wt%, or from about 0.1 wt% to about 4 wt%.

[0122] Molybdenum-containing components: The lubricating oil compositions herein may also optionally contain one or more molybdenum-containing compounds. Oil-soluble molybdenum compounds may have functional performance as antiwear agents, antioxidants, friction modifiers, or mixtures thereof. Oil-soluble molybdenum compounds may include molybdenum dithiocarbamate, molybdenum dialkyldithiophosphate, molybdenum dithiophosphinate, amine salts of molybdenum compounds, molybdenum xanthate, molybdenum thioxanthate, molybdenum sulfide, molybdenum carboxylate, molybdenum alkoxide, trinuclear organomolybdenum compounds, and / or mixtures thereof. Molybdenum sulfide may include molybdenum disulfide. Molybdenum disulfide may be in the form of a stable dispersion. In one embodiment, the oil-soluble molybdenum compound may be selected from the group consisting of molybdenum dithiocarbamate, molybdenum dialkyldithiophosphate, amine salts of molybdenum compounds, and mixtures thereof. In one embodiment, the oil-soluble molybdenum compound may be molybdenum dithiocarbamate.

[0123] Suitable examples of molybdenum compounds that can be used include Molyvan822 (trademark), Molyvan (trademark) A, Molyvan2000 (trademark), and Molyvan855 (trademark) of R.T. Vanderbilt Co., Ltd., and commercially available materials sold under trade names such as Sakura-Lube (trademark) S-165, S-200, S-300, S-310G, S-525, S-600, S-700, and S-710 available from Adeka Corporation, and mixtures thereof. Suitable molybdenum components are described in U.S. Patent No. 5,650,381, U.S. Reissue Patent No. RE37,363 (E1), U.S. Reissue Patent No. RE38,929 (E1), and U.S. Reissue Patent No. RE40,595 (E1), the entireties of which are incorporated herein by reference.

[0124] Furthermore, the molybdenum compound can be an acidic molybdenum compound. Included are molybdic acid, ammonium molybdate, sodium molybdate, potassium molybdate, and other alkali metal molybdates and other molybdenum salts, such as sodium hydrogen molybdate, MoOCl4, MoO2Br2, Mo2O3Cl6, molybdenum trioxide or similar acidic molybdenum compounds. Alternatively, the composition can provide molybdenum by a molybdenum / sulfur complex of a basic nitrogen compound, as described, for example, in U.S. Patent Nos. 4,263,152, 4,285,822, 4,283,295, 4,272,387, 4,265,773, 4,261,843, 4,259,195, and 4,259,194, and International Publication No. 94 / 06897, the aforementioned patent documents being incorporated herein by reference in their entireties.

[0125] Suitable organomolybdenum compounds of another class are trinuclear molybdenum compounds such as compounds of the formula Mo3SkLnQz and mixtures thereof, where S represents sulfur, L represents independently selected ligands having a sufficient number of carbon atoms such that the compound is soluble or dispersible in oil, n is from 1 to 4, k varies from 4 to 7, Q is selected from the group of neutral electron-donating compounds such as water, amines, alcohols, phosphines, and ethers, z is in the range from 0 to 5, including non-stoichiometric values. Among the organic groups of all ligands, there may be present at least 21 total carbon atoms, such as at least 25, at least 30, or at least 35 carbon atoms. Additional suitable molybdenum compounds are described in U.S. Patent No. 6,723,685, which is hereby incorporated by reference in its entirety.

[0126] The oil-soluble molybdenum compound may be present in an amount sufficient to provide from about 0.5 ppm to about 2000 ppm, from about 1 ppm to about 700 ppm, from about 1 ppm to about 550 ppm, from about 5 ppm to about 300 ppm, or from about 20 ppm to about 250 ppm of molybdenum.

[0127] Transition metal-containing compounds: In another embodiment, the oil-soluble compound may be a transition metal-containing compound or a metalloid. Transition metals may include, but are not limited to, titanium, vanadium, copper, zinc, zirconium, molybdenum, tantalum, tungsten, etc. Suitable metalloids include, but are not limited to, boron, silicon, antimony, tellurium, etc.

[0128] In certain embodiments, the oil-soluble transition metal-containing compound may function as an antiwear agent, a friction modifier, an antioxidant, an adhesion control additive, or two or more of these functions. In certain embodiments, the oil-soluble transition metal-containing compound may be an oil-soluble titanium compound such as titanium(IV) alkoxide. Among the titanium-containing compounds that can be used or can be used therefor in the preparation of the oil-soluble materials of the technology of the present disclosure, there are titanium(IV) oxide; titanium(IV) sulfide; titanium(IV) nitrate; titanium(IV) alkoxides such as titanium methoxide, titanium ethoxide, titanium propoxide, titanium isopropoxide, titanium butoxide, titanium 2-ethylhexoxide; and, without limitation, other titanium compounds or complexes such as titanium phenate; titanium carboxylates such as titanium(IV) 2-ethyl-1,3-hexanedioate or titanium citrate or titanium oleate; and various Ti(IV) compounds such as titanium(IV)(triethanolaminato)isopropoxide. Other forms of titanium encompassed by the disclosed technology include titanium phosphates such as titanium dithiophosphate (e.g., dialkyldithiophosphate) and titanium sulfonate (e.g., alkylbenzenesulfonate), or generally reaction products of titanium compounds that form salts such as oil-soluble salts with various acid substances. Thus, the titanium compounds can be derived, inter alia, from organic acids, alcohols, and glycols. The Ti compounds may also exist in dimer or oligomer form containing a Ti-O-Ti structure. Such titanium materials are commercially available or can be readily prepared by suitable synthetic techniques known to those skilled in the art. These may exist as solids or liquids at room temperature depending on the particular compound. These may also be provided in solution form in a suitable inert solvent.

[0129] In one embodiment, titanium can be supplied as a Ti-modified dispersant such as a succinimide dispersant. Such materials may be prepared by forming a titanium mixed anhydride between a titanium alkoxide and a hydrocarbyl-substituted succinic anhydride such as alkenyl- (or alkyl) succinic anhydride. The resulting titanium succinate intermediate may be used directly or reacted with any of several materials such as (a) a polyamine-based succinimide / amide dispersant having a free condensable -NH functional group, (b) components of the polyamine-based succinimide / amide dispersant, namely, alkenyl (or alkyl) succinic anhydride and polyamine, (c) a hydroxy-containing polyester dispersant prepared by reaction of a substituted succinic anhydride with a polyol, amino alcohol, polyamine, or mixtures thereof. Alternatively, the titanium succinate intermediate may be reacted with other agents such as an alcohol, amino alcohol, ether alcohol, polyether alcohol or polyol, or a fatty acid, and the product may be used directly to impart Ti to a lubricant or may be further reacted with a succinic dispersant as described above. By way of example, 1 part (mole) of tetraisopropyl titanate may be reacted with about 2 parts (mole) of polyisobutene-substituted succinic anhydride at 140 - 150 °C for 5 - 6 hours to provide a titanium-modified dispersant or intermediate. The resulting material (30 g) may be further reacted at 150 °C for 1.5 hours with a succinimide dispersant from a polyisobutene-substituted succinic anhydride and polyethylene polyamine mixture (127 grams + diluent oil) to produce a titanium-modified succinimide dispersant.

[0130] Another titanium-containing compound may be the reaction product of a titanium alkoxide and a C6 - C 25 carboxylic acid. The reaction product may be represented by the following formula,

[0131] [Chemical formula] In the formula, n is an integer selected from 2, 3, and 4, R is a hydrocarbyl group containing about 5 to about 24 carbon atoms, or may be represented by the following formula,

[0132]

Chemical formula

[0133]

Chemical formula

[0134] Suitable carboxylic acids may include, but are not limited to, caproic acid, caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, oleic acid, erucic acid, linoleic acid, linolenic acid, cyclohexanecarboxylic acid, phenylacetic acid, benzoic acid, neodecanoic acid, etc.

[0135] In certain embodiments, the oil-soluble titanium compound may be present in the lubricating oil composition in an amount providing about 0 to about 3000 weight ppm of titanium, or about 25 to about 1500 weight ppm of titanium, or about 35 weight ppm to about 500 weight ppm of titanium, or about 50 ppm to about 300 ppm.

[0136] Viscosity index improver: The lubricating oil composition of this specification may also optionally contain one or more viscosity index improvers. Suitable viscosity index improvers may include polyolefins, olefin copolymers, ethylene / propylene copolymers, polyisobutene, hydrogenated styrene-isoprene polymers, styrene / maleic acid ester copolymers, hydrogenated styrene / butadiene copolymers, hydrogenated isoprene polymers, alpha-olefin maleic anhydride copolymers, polymethacrylates, polyacrylates, polyalkylstyrenes, hydrogenated alkenylaryl conjugated diene copolymers, or mixtures thereof. The viscosity index improver may include star polymers, and suitable examples are described in U.S. Publication No. 2012 / 0101017 A1.

[0137] The lubricating oil composition of this specification may optionally contain one or more dispersant viscosity index improvers in addition to or instead of the viscosity index improver. Suitable dispersant viscosity index improvers include functionalized polyolefins, such as ethylene-propylene copolymers functionalized with the reaction product of an acylating agent (such as maleic anhydride) and an amine; polymethacrylates functionalized with an amine, or esterified maleic anhydride-styrene copolymers reacted with an amine.

[0138] The total amount of the viscosity index improver and / or the dispersant viscosity index improver may be about 0 wt% to about 20 wt%, about 0.1 wt% to about 15 wt%, about 0.1 wt% to about 12 wt%, or about 0.5 wt% to about 10 wt% of the lubricating oil composition.

[0139] Other optional additives: Other additives may be selected to perform one or more functions required for the lubricating fluid. Further, one or more of the aforementioned additives may be multifunctional and may provide additional functions in addition to or other than the functions described herein.

[0140] The lubricating oil composition according to the present disclosure may optionally contain other performance additives. The other performance additives may be additional to the specific additives of the present disclosure and / or may include one or more of a metal deactivator, a viscosity index improver, a detergent, an ashless TBN booster, a friction modifier, an antiwear agent, a corrosion inhibitor, a rust inhibitor, a dispersant, a dispersant viscosity index improver, an extreme pressure agent, an antioxidant, an antifoaming agent, a demulsifier, an emulsifier, a pour point depressant, a seal swell agent, and mixtures thereof. Typically, a fully formulated lubricating oil contains one or more of these performance additives.

[0141] Suitable metal deactivators include derivatives of benzotriazole (typically tolyltriazole), dimercaptothiadiazole derivatives, 1,2,4-triazole, benzimidazole, 2-alkyldithiobenzimidazole, or 2-alkyldithiobenzothiazole; antifoaming agents including copolymers of ethyl acrylate, 2-ethylhexyl acrylate, and optionally vinyl acetate; demulsifiers including trialkyl phosphate, polyethylene glycol, polyethylene oxide, polypropylene oxide, and (ethylene oxide - propylene oxide) polymers; and pour point depressants including esters of maleic anhydride - styrene, polymethacrylate, polyacrylate, or polyacrylamide.

[0142] Suitable antifoaming agents include silicon-based compounds such as siloxanes.

[0143] Suitable pour point depressants may include polymethyl methacrylate or mixtures thereof. The pour point depressant may be present in an amount sufficient to provide from about 0 wt% to about 1 wt%, from about 0.01 wt% to about 0.5 wt%, or from about 0.02 wt% to about 0.04 wt% based on the final weight of the lubricating oil composition.

[0144] Suitable rust inhibitors may be a single compound or a mixture of compounds having the property of suppressing corrosion of the ferrous metal surface. Non-limiting examples of rust inhibitors useful herein include oil-soluble high molecular weight organic acids such as 2-ethylhexanoic acid, lauric acid, myristic acid, palmitic acid, oleic acid, linoleic acid, linolenic acid, behenic acid, and serotic acid, and oil-soluble polycarboxylic acids including dimeric and trimeric acids such as those produced from tall oil fatty acid, oleic acid, and linoleic acid. Other suitable corrosion inhibitors include long-chain alpha, omega-dicarboxylic acids in the molecular weight range of about 600 to about 3000, and alkenyl succinic acids having an alkenyl group containing about 10 or more carbon atoms such as tetrapropenyl succinic acid, tetradecenyl succinic acid, and hexadecenyl succinic acid. Another useful type of acidic corrosion inhibitor is a half ester of an alkenyl succinic acid having about 8 to about 24 carbon atoms in the alkenyl group and an alcohol such as polyglycol. The corresponding half amides of such alkenyl succinic acids are also useful. Useful rust inhibitors are high molecular weight organic acids. In some embodiments, the engine oil does not contain a rust inhibitor.

[0145] When present, the rust inhibitor can be used in an amount sufficient to provide from about 0 wt% to about 5 wt%, from about 0.01 wt% to about 3 wt%, from about 0.1 wt% to about 2 wt% based on the final weight of the lubricating oil composition.

[0146] Generally speaking, suitable crankcase lubricants may contain additive components within the ranges listed in the following table.

[0147]

Table 2

[0148] The percentages of the above components represent the weight percentages of the components based on the weight of the final lubricating oil composition. The remainder of the lubricating oil composition consists of one or more base oils. The additives used when formulating the compositions described herein can be blended into the base oil individually or in various partial combinations. However, it may be suitable to use an additive concentrate (i.e., an additive plus a diluent such as a hydrocarbon solvent) to simultaneously mix all of the components.

Examples

[0149] The following examples illustrate exemplary embodiments of the present disclosure. In these examples, as well as elsewhere in this application, all ratios, parts, and percentages are by weight unless otherwise indicated. These examples are presented for illustrative purposes only and are not intended to limit the scope of the invention disclosed herein.

[0150] Example 1 Engine oils formulated for 0W-20 oil grades and containing individually a modified styrene-maleic anhydride copolymer (PSMA) or a poly(meth)acrylate copolymer (PMA) were evaluated according to the MRV test (ASTM D4684 at -40 °C) as shown in Table 3 below. Even at a copolymer treatment rate of 0.5 weight percent, the formulations could not pass the MRV test with either the PSMA or PMA polymer alone. As shown in Table 3 below, only the polymers described were changed while keeping the base formulation constant. The base formulation was prepared to meet ILSAC GF-6 and contained in suitable amounts a succinimide dispersant for a DI pack, a borated succinimide dispersant, overbased calcium sulfonate, overbased magnesium sulfonate, zinc dialkyldithiophosphate, an alkylated diphenylamine antioxidant, an antifoaming agent, an organic friction modifier, and a base oil. Base oil 1 and base oil 2 are Group III base oils. The viscosity modifier was an olefin copolymer. The polymers considered for this example are further described in Table 4 below. The MRV viscosity and yield stress were measured according to ASTM D4684, and the kinematic viscosity was measured according to ASTM D445. An acceptable MRV includes a viscosity of less than 60,000 cP and a yield stress of less than 35. A reparted yield stress of <70 means that the yield stress was between 35 and 75 according to the reparted convention of the test method.

[0151]

Table 3

[0152]

Table 4

[0153] Example 2 In this example, the PSMA polymer and the PMA copolymer of Example 1 are combined. Surprisingly, it has been discovered that when different chemicals are combined, such copolymer mixtures can help pass the MRV test. Table 5 below shows that inventive examples I1, I2, and I3 having combinations of PSMA and PMA polymers help pass the MRV test.

[0154]

Table 5

[0155] Example 3 In this example, only different PMA copolymers of Example 1 are combined. Examples C5 and C6 in Table 6 show that combinations of PMA-1, PMA-2, and PMA-3 failed the MRV test.

[0156]

Table 6

[0157] Example 4 This example evaluates different ratios of the PSMA and PMA copolymers of Example 1. Comparative examples C7 and C8 in Table 7 show ratios that could not pass the MRV test, but the ratios in samples I4-I7 of the present invention were able to achieve MRV performance at the passing level. The fluid in this example contained a lubricant composition as described in Example 1, except as described in Table 7 below.

[0158]

Table 7

[0159] Example 5 This example uses the polymer of Example 1 to evaluate different processing rates of the total PSMA and PMA polymer blends. Comparative Examples C9 and C11 in Table 8 show that the lower total processing rates of the two polymers failed to pass the MRV test, while Samples I8 - I12 of the present invention achieved MRV performance at the passing level. The fluid in this example contained a lubricant composition as described in Example 1, except as described in Table 8 below.

[0160]

Table 8

[0161] It should be noted that as used in this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless expressly and unambiguously limited to one referent. Thus, for example, reference to "an antioxidant" includes two or more different antioxidants. As used herein, the term "include" and its grammatical variations are intended to be non - limiting, and the listing of items in a list does not exclude other similar items that can be substituted or added to the listed items.

[0162] For the purposes of this specification and the appended claims, unless otherwise indicated, all numbers representing amounts, percentages or ratios, and other numerical values used in this specification and the claims are to be understood in all instances as being modified by the term "about". Thus, unless otherwise indicated, the numerical parameters set forth in the following specification and appended claims are approximations that may vary depending upon the desired properties sought to be obtained by the present disclosure. At a minimum, and not as an attempt to limit the application of the doctrine of equivalents to the claims, each numerical parameter should be construed in light of the reported number of significant digits and by applying ordinary rounding techniques.

[0163] It should be understood that each component, compound, substituent or parameter disclosed herein is disclosed for use alone or in combination with one or more of any other component, compound, substituent or parameter disclosed herein.

[0164] It is further understood that each range disclosed herein should be interpreted as a disclosure of each specific value within the disclosed range having the same significant figures. Thus, for example, the range of 1 to 4 should be interpreted as an explicit disclosure of the values 1, 2, 3, and 4 and any range of such values.

[0165] It is further understood that each lower limit of each range disclosed herein should be interpreted as being disclosed in combination with each upper limit of each range and each specific value within each range for the same component, compound, substituent or parameter. Thus, the present disclosure should be interpreted as a disclosure of all ranges derived by combining each lower limit of each range with each upper limit of each range or each specific value within each range, or by combining each upper limit of each range with each specific value within each range. That is, it is further understood that any range between the endpoint values within a broad range is also discussed herein. Thus, the range of 1 to 4 also means ranges such as 1 to 3, 1 to 2, 2 to 4, 2 to 3, etc.

[0166] Furthermore, a specific amount / value of a component, compound, substituent or parameter disclosed in the description or examples should be interpreted as a disclosure of either the lower or upper limit of a range, and thus can be combined with a range or any other lower or upper limit of a specific amount / value for the same component, compound, substituent or parameter disclosed elsewhere in this application to form a range for that component, compound, substituent or parameter.

[0167] Although specific embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are not currently foreseen or that cannot be foreseen may occur to the applicant or other persons skilled in the art. Accordingly, the appended claims, which may be filed and amended, are intended to cover all such alternatives, modifications, variations, improvements, and substantial equivalents.

Claims

1. A low-temperature stable lubricating composition exhibiting pumpability, comprising: a base oil having a lubricating viscosity; and 0.5 to 1.0 weight percent of a polymer additive comprising a blend of a modified styrene-maleic anhydride copolymer and a poly(meth)acrylate copolymer effective to maintain a pumpable fluid.

2. The low-temperature stable lubricating composition according to claim 1, further comprising one or more of a succinimide dispersant, a borated succinimide dispersant, overbased calcium sulfonate, overbased magnesium sulfonate, zinc dialkyldithiophosphate, an alkylated diphenylamine antioxidant, an antifoaming agent, or a combination thereof.

3. The low-temperature stable lubricating composition according to claim 1, wherein the modified styrene-maleic anhydride copolymer is an esterified styrene-maleic anhydride copolymer.

4. The low-temperature stable lubricating composition according to claim 3, wherein the esterified styrene-maleic anhydride copolymer is esterified with a long-chain alcohol having an alkyl chain length of 10 to 22 carbons.

5. The low-temperature stable lubricating composition according to claim 3 or 4, wherein the esterified styrene-maleic anhydride copolymer has a number average molecular weight of 10,000 to 100,000.

6. The low-temperature stable lubricating composition according to any one of claims 1 to 5, wherein the poly(meth)acrylate copolymer comprises a reactant selected from C1-C24 linear or branched alkyl (meth)acrylate reactants.

7. The low-temperature stable lubricating composition according to any one of claims 1 to 6, wherein the poly(meth)acrylate copolymer has a number average molecular weight of 20,000 or more.

8. The ratio of the modified styrene-maleic anhydride copolymer to the poly(meth)acrylate copolymer is from 1:2 to 1:0.7, the low-temperature stable lubricating composition according to any one of claims 1 to 7.

9. The polymer additive contains 40 to 60 weight percent of the modified styrene-maleic anhydride copolymer based on the total weight of the modified styrene-maleic anhydride copolymer and the poly(meth)acrylate copolymer, the low-temperature stable lubricating composition according to any one of claims 1 to 8.

10. A method for producing the low-temperature stable lubricating composition according to any one of claims 1 to 9, including adding a polymer additive of 0.5 to 1.0 weight percent containing a blend of a modified styrene-maleic anhydride copolymer and a poly(meth)acrylate copolymer, which is effective for maintaining a pumpable fluid, to a base oil having a lubricating viscosity.

11. Use of the low-temperature stable lubricating composition according to any one of claims 1 to 9 as a lubricant.

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