Lubricating oil composition

Abstract

This invention relates to crankcase lubricating oil compositions for four-wheeled or more-wheeled vehicles, comprising or prepared by mixing the following components: (A) an oil of lubricating viscosity in a predominant amount; (B) an oil-soluble or oil-dispersible molybdenum-containing additive providing 700-1200 ppm molybdenum atoms to the lubricating oil composition; (C) a detergent composition containing one or more magnesium sulfonate detergents in an amount providing 200-4000 ppm magnesium atoms to the lubricating oil composition, wherein the detergent composition further comprises calcium salicylate detergent; and (D) an oil-soluble or oil-dispersible borate dispersant compound present in the lubricating oil composition in an amount sufficient to provide 200-600 ppm boron atoms to the lubricating oil composition, wherein the ratio of detergent atom metal to atomic molybdenum in the lubricating oil composition is less than 3, and wherein the borate dispersant compound comprises borate-treated polyolefin succinimide.

Description

[0001] This application is a divisional application of the invention patent application with application number 201710511764.0, the original application being filed on June 29, 2017, and the invention being entitled "Lubricating Oil Composition". Technical Field

[0002] This invention relates to automotive lubricant compositions for four-wheeled or more-wheeled vehicles that exhibit improved frictional properties. More specifically, this invention relates to automotive crankcase lubricant compositions for gasoline (spark ignition) and diesel (compression ignition) internal combustion engines, such compositions being referred to as crankcase lubricants; and to the use of additives in such lubricant compositions for reducing friction between moving parts in the use of such engines and / or improving the fuel economy of engines lubricated with said lubricant compositions. Background Technology

[0003] Crankcase lubricant is a general lubricating oil used in internal combustion engines, where the oil sump is typically located below the crankshaft and the circulating oil returns to it. To reduce engine energy and fuel consumption, crankcase lubricant is needed to reduce overall engine friction. Reducing frictional losses in the engine significantly helps improve fuel economy and fuel economy retention. The use of friction modifiers to achieve improved frictional properties has long been known.

[0004] Oil-soluble molybdenum-containing additives can be used due to their friction-reducing properties. Examples of patent applications relating to oil-soluble molybdenum additives for use in lubricant compositions include U.S. Patent Nos. 4,164,473; 4,176,073; 4,176,074; 4,192,757; 4,248,720; 4,201,683; 4,289,635 and 4,479,883. In some markets, such as Japan, high levels of molybdenum-containing additives, such as molybdenum dithiocarbamate, are commonly used as friction modifiers to achieve low friction. In these applications, up to 1000 ppm of molybdenum atoms can be present in the lubricant.

[0005] U.S. Patent Application No. 6,074,993 illustrates how a combination of dimer and trimer molybdenum compounds can improve fuel economy and wet clutch performance in lubricants containing ZDDP and calcium sulfonate and / or magnesium detergents.

[0006] International patent application No. WO99 / 47629 relates to a lubricant containing a calcium detergent and a trinuclear molybdenum additive, which has improved friction-reducing properties. Data shows that the combination of the trinuclear molybdenum compound and calcium sulfonate exhibits improved friction-reducing properties while maintaining them.

[0007] Adding boron to lubricating oil compositions to improve wear performance is well-known. However, in some oil compositions, high boron content can lead to increased boundary friction.

[0008] International patent application WO 96 / 19551 discloses an engine oil comprising a boron-containing alkenyl succinimide providing greater than 800 ppm of atomic boron, molybdenum dithiophosphate or molybdenum dithiocarbamate providing 50-2000 ppm of molybdenum atoms, calcium salicylate providing 50-4000 ppm of calcium atoms, magnesium salicylate providing 50-4000 ppm of magnesium, and optionally a copolymer of ethylene with at least one other α-olefin monomer. The lubricating oil composition of WO 96 / 19551 is said to exhibit improved fuel economy and fuel economy retention performance.

[0009] Additionally, international patent application WO 96 / 37582 discloses a lubricating oil composition comprising molybdenum dithiocarbamate thiooxymethylene providing 200-1000 ppm molybdenum atoms to the oil, zinc dialkyldithiocarbamate containing a primary alkyl group and providing 0.04-0.15 wt% phosphorus atoms to the oil, and a mixture containing 50-100 wt% calcium alkyl salicylate and 0-50 wt% magnesium alkyl salicylate. This lubricating oil is said to have good anti-wear properties and maintain friction-reducing properties.

[0010] US Patent No. 5,631,212 discloses a lubricant comprising an oil-soluble copper salt, an oil-soluble molybdenum salt, a Group II metal salicylate, and a borate-modified polyolefin succinimide, and is said to provide good fuel economy, wear and oxidation resistance.

[0011] In addition, European patent application No. EP 0 562 172 discloses a lubricant comprising borate-modified alkenyl succinimide, an alkaline earth metal salt of salicylic acid, and 100-2000 ppm of molybdenum atoms from molybdenum compounds selected from molybdenum dithiophosphate and molybdenum dithiocarbamate, which is believed to be able to reduce frictional losses in engines.

[0012] As fuel economy regulations become increasingly stringent and engine designs evolve, fuel economy testing becomes increasingly closely tied to engine operation. It is increasingly important to reduce friction and thus improve fuel economy across the entire engine operating temperature range, including fuel economy at low temperatures present during engine startup (e.g., from ambient temperature (40°C) to below 0°C). Therefore, crankcase lubricants that exhibit desirable frictional characteristics, reducing frictional losses during engine startup and across the entire engine operating temperature range, thereby improving fuel economy, remain essential. Summary of the Invention

[0013] This invention provides a crankcase lubricating oil composition comprising or prepared by mixing the following components: (A) The main amount of lubricating viscosity oil; (B) To provide the lubricating oil composition with an oil-soluble or oil-dispersible molybdenum-containing additive of 600-1500 ppm molybdenum atoms as measured according to ASTM D5185. (C) A detergent composition containing one or more magnesium sulfonates, providing the lubricating oil composition with an amount of 200-4000 ppm magnesium atoms as measured according to ASTM D5185, and (D) An oil-soluble or oil-dispersible boron compound present in the lubricating oil composition in an amount sufficient to provide 200-600 ppm boron atoms as determined according to ASTM D5185.

[0014] In one embodiment of the invention, the detergent composition further comprises one or more additional detergent additives selected from magnesium salicylate, magnesium phenolate, calcium salicylate, calcium phenolate, and / or calcium sulfonate detergents. Preferably, the lubricating oil composition of the invention comprises a detergent composition consisting of a mixture of one or more magnesium sulfonate detergents and one or more calcium salicylate detergents.

[0015] Surprisingly, it has been found that the use of magnesium sulfonate detergents in lubricating oil compositions containing large amounts of oil-soluble or oil-dispersible molybdenum compounds provides unexpected improvements in the frictional properties of said lubricating oil compositions, particularly at low temperatures. Accordingly, the reduction in friction typically translates into improved fuel economy.

[0016] The present invention provides a method for lubricating a spark ignition or compression ignition internal combustion engine, comprising lubricating the engine with a lubricating oil composition as defined in the present invention.

[0017] The present invention further provides the use of a magnesium-containing detergent in a crankcase lubricating oil composition to reduce boundary friction measurements in the lubricating oil composition by providing an amount of 200-4000 ppm magnesium as measured according to ASTM D5185, the reduction being compared to a comparable lubricant that does not contain an amount of the magnesium-containing detergent sufficient to provide 200-4000 ppm magnesium to the lubricating oil composition.

[0018] In one embodiment of the invention, the lubricating oil composition further comprises an oil-soluble or oil-dispersible molybdenum compound present in the lubricating oil composition in an amount sufficient to provide 500-1500 ppm of molybdenum atoms as measured according to ASTM D5185, and an oil-soluble or oil-dispersible boron-containing compound present in the lubricating oil composition in an amount sufficient to provide 200-600 ppm of boron atoms as measured according to ASTM D5185.

[0019] The lubricant of the present invention is suitable for the lubrication of the crankcase of spark-ignition or compression-ignition internal combustion engines.

[0020] In one embodiment of the invention, the magnesium-containing detergent is one or more detergents selected from the group consisting of oil-soluble neutral and superalkaline magnesium sulfonates, magnesium phenolate, magnesium sulfide phenolate, magnesium thiophosphonate, magnesium salicylate, and magnesium naphthenate, as well as other oil-soluble magnesium carboxylates. Preferably, the magnesium-containing detergent is magnesium sulfonate.

[0021] In another embodiment of the invention, the lubricating oil composition further comprises other detergent additives selected from magnesium salicylate, magnesium phenolate, calcium salicylate, calcium phenolate, and / or calcium sulfonate detergents. Preferably, the lubricating oil composition having the purpose of the invention comprises a detergent composition consisting of a mixture of one or more magnesium sulfonate detergents and one or more calcium salicylate detergents.

[0022] It has been unexpectedly found that the use of magnesium-containing detergents in lubricating oil compositions comprising large amounts of oil-soluble or oil-dispersible molybdenum compounds and oil-soluble or oil-dispersible boron compounds provides unexpected improvements in the frictional properties of said lubricating oil compositions. This improvement is further enhanced if the magnesium detergent is magnesium sulfonate and is used in conjunction with a calcium-containing detergent, preferably calcium salicylate. Accordingly, the reduction in friction typically translates into improved fuel economy.

[0023] The present invention further provides the use of the lubricating oil composition according to the invention in reducing the coefficient of friction between metal contact surfaces in an engine during engine operation in the crankcase lubrication of a spark-ignition or compression-ignition internal combustion engine, the reduction being compared to the use of a lubricant containing a magnesium-containing detergent that does not contain an amount sufficient to provide 200-4000 ppm magnesium (ASTM D5185) to the lubricating oil composition.

[0024] The present invention provides a method for improving the fuel economy of a spark-ignition or compression-ignition internal combustion engine, the method comprising lubricating the engine with the lubricating oil composition of the present invention and operating the engine.

[0025] In this specification, the following words and expressions (if used and when used) have the meanings given below: "Active ingredient" or "(ai)" refers to an additive material that is not a diluent or solvent; The word “comprising” or any similar language indicates the presence of the described feature, step, or whole or component, but does not exclude the presence or addition of one or more other features, steps, wholes, components, or combinations thereof; the expression “consisting of” or “mainly composed of” or similar expressions may be included within the expression “comprising” or similar expressions, wherein “mainly composed of” allows the inclusion of substances that do not substantially affect the properties of the composition to which it is applied; "Hydrocarbon group" refers to a chemical group in a compound containing hydrogen and carbon atoms, which is directly bonded to the other parts of the compound via carbon atoms. The group may contain one or more atoms other than carbon and hydrogen, as long as they do not affect the essentially hydrocarbon nature of the group. Suitable groups are known to those skilled in the art (e.g., halogens, especially chlorine and fluorine, amino, alkoxy, mercapto, alkyl mercapto, nitro, nitroso, thiooxy, etc.). Preferably, the group is primarily composed of hydrogen and carbon atoms, unless otherwise specified. Preferably, the hydrocarbon group includes aliphatic hydrocarbon groups. The term "hydrocarbon group" includes "alkyl," "alkenyl," "allyl," and "aryl" as defined herein. "Alkyl" refers to a C1-C group that is directly bonded to the rest of the compound via a single carbon atom. 30 Alkyl groups. Unless otherwise specified, alkyl groups can be straight-chain (i.e., unbranched) or branched, and can be cyclic, acyclic, or partially cyclic / acyclic, when a sufficient number of carbon atoms are present. Preferably, alkyl groups include straight-chain or branched acyclic alkyl groups. Representative examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, hexyl, heptyl, octyl, dimethylhexyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecanyl, octadecyl, nonadecanyl, eicosyl, and triacontyl; "Aryl" refers to a C6-C group that is optionally substituted with one or more alkyl, halogen, hydroxyl, alkoxy, and amino groups. 18 C6-C is preferred. 10 Aromatic groups are directly bonded to the rest of the compound via a single carbon atom. Preferred aryl groups include phenyl and naphthyl groups and their substituted derivatives, particularly their phenyl and alkyl-substituted derivatives; "Alkenyl" refers to a C2-C group that includes at least one carbon-carbon double bond and is directly bonded to the rest of the compound via a single carbon atom. 30 C2-C is preferred. 12 Groups, and otherwise defined as "alkyl"; "Alkylene" refers to a C2-C chain that can be straight-chain or branched. 20 C2-C is preferred. 10More preferably, C2-C6 divalent saturated acyclic aliphatic groups. Representative examples of alkylene groups include ethylene, propylene, butylene, isobutylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, 1-methylethylene, 1-ethylethylene, 1-ethyl-2-methylethylene, 1,1-dimethylethylene, and 1-ethylpropylene; "Polyol" refers to an alcohol comprising two or more hydroxyl functional groups (i.e., a polyhydroxy alcohol), but excludes "polyalkylene glycols" (component B (ii)) used to form oil-soluble or oil-dispersible polymer friction modifiers. More specifically, the term "polyol" encompasses glycols, triols, tetraols, and / or related dimers or chain-extended polymers of these compounds. Even more specifically, the term "polyol" encompasses glycerol, neopentyl glycol, trimethylolethane, trimethylolpropane, trimethylolbutane, pentaerythritol, dipentaerythritol, tripentaerythritol, and sorbitol; "Polycarboxylic acids" refer to organic acids comprising two or more carboxylic acid functional groups, preferably hydrocarbon acids. The term "polycarboxylic acids" encompasses di-, tri-, and tetracarboxylic acids; "Halogen" or "halogenated elements" includes fluorine, chlorine, bromine, and iodine; The terms “oil-soluble” or “oil-dispersible” or similar terms as used herein do not necessarily mean that a compound or additive is soluble, miscible, or able to be suspended in the oil in all proportions. However, these terms do mean that they are soluble or stably dispersed in the oil, for example, to a degree sufficient to achieve their intended effect in the environment in which the oil is applied. Furthermore, the additional introduction of other additives may allow for the introduction of higher levels of a particular additive if desired. The term "ashless" in relation to additives means that the additive does not contain metals; "Hash content" in relation to additives refers to the presence of metals in the additives; "Main amount" means more than 50% by mass of the composition in terms of the components mentioned and the total mass of the composition, calculated as the active ingredient of the components; "Minor amount" means less than 50% by mass of the additives mentioned and of the total mass of the composition, calculated based on the active ingredient of the additives. The “effective minor amount” in relation to an additive refers to the amount of such additive in a lubricating oil composition that enables the additive to provide the desired technical effect; "ppm" refers to parts by mass per million parts, based on the total mass of the lubricating oil composition. The “metal content” of a lubricating oil composition or additive component, such as the detergent metal, molybdenum or boron content of the lubricating oil composition, or the total metal content (i.e. the sum of all individual metal contents), is measured by ASTM D5185. In relation to the additive components or lubricating oil compositions of this invention, “TBN” refers to the total base number (mg KOH / g) as measured by ASTM D2896. KV 100 "" refers to the kinematic viscosity at 100°C as measured by ASTM D445; "Phosphorus content" is measured according to ASTM D5185; "Sulfur content" is measured according to ASTM D2622; and "Sulfate ash content" is measured according to ASTM D874.

[0026] All reported percentages are based on the mass percentage of the active ingredient, i.e., without regard to carriers or diluent oils, unless otherwise stated.

[0027] Furthermore, it should be understood that the various components used (necessary, optimal, and commonly used components) may react under the conditions of formulation, storage, or use, and therefore the present invention also provides products that can be obtained or acquired by any such reaction.

[0028] In addition, it should be understood that any upper and lower limits, ranges and proportions given in this article can be combined independently.

[0029] Furthermore, it should be understood that preferred features of each aspect of the invention are considered to be preferred features of each other aspect of the invention. Detailed Implementation

[0030] The features of the invention relating to various and all aspects thereof, if appropriate, will now be described in more detail below: Oil of lubricating viscosity (A) A lubricating viscosity oil (sometimes called a "base oil" or "base oil") is the main liquid component of a lubricant, into which additives and possibly other oils are incorporated to, for example, create a final lubricant (or lubricant composition). Base oils can be used to manufacture concentrates and lubricant compositions made from them, and can be selected from natural (plant, animal, or mineral) and synthetic lubricants and mixtures thereof.

[0031] The base oil grouping is defined in the American Petroleum Institute (API) publication "Engine Oil Licensing and Certification System," Industry Service Department, 14th edition, December 1996, Appendix 1, December 1998. Typically, the base oil has a preferred particle size of 3-12, more preferably 4-10, and most preferably 4.5-8 mm at 100°C. 2 Viscosity / s (cSt).

[0032] The definitions of base oils and base petroleum products used in this invention are identical to those in the American Petroleum Institute (API) publication "Engine Oil Licensing and Certification System," Industry Service Department, 14th edition, December 1996, Appendix 1, December 1998. That publication classifies base oils as follows: a) Group I base oils contain less than 90% saturates and / or more than 0.03% sulfur, and have a viscosity index greater than or equal to 80 and less than 120, and are tested using the methods specified in Table E-1.

[0033] b) Group II base oils contain 90% or more of saturates and 0.03% or less of sulfur, and have a viscosity index greater than or equal to 80 and less than 120, and are tested using the methods specified in Table E-1.

[0034] c) Group III base oils contain 90% or more of saturates and 0.03% or less of sulfur, and have a viscosity index of 120 or more, and are tested using the methods specified in Table E-1.

[0035] d) Group IV base oils are polyalphaolefins (PAO).

[0036] e) Group V base oils include all other base oils not included in Groups I, II, III or IV.

[0037] Table E-1: Analytical Methods for Base Oils

[0038] Other oils with lubricating viscosities that may be included in a lubricating oil composition are described in detail below: Natural oils include animal and vegetable oils (such as castor oil and lard), liquid petroleum, and hydrorefined, solvent-treated alkyl, cycloalkane, and mixed alkyl-cycloalkane mineral lubricants. Oils with lubricating viscosities derived from coal or shale are also available as base oils.

[0039] Synthetic lubricants include hydrocarbon oils such as polymeric and interpolymerized olefins (e.g., polybutene, polypropylene, propylene-isobutylene copolymer, chlorinated polybutene, poly(1-hexene), poly(1-octene), poly(1-decene)); alkylbenzenes (e.g., dodecylbenzene, tetradecylbenzene, dinonylbenzene, di(2-ethylhexyl)benzene); polyphenols (e.g., biphenyl, terphenyl, alkylated polyphenols); and alkylated diphenyl ethers and alkylated diphenyl sulfides, as well as their derivatives, analogues and homologues.

[0040] Another suitable class of synthetic lubricants includes esters of dicarboxylic acids (such as phthalic acid, succinic acid, alkyl succinic acid and alkenyl succinic acid, maleic acid, azelaic acid, octanoic acid, sebacic acid, fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkyl malonic acid, alkenyl malonic acid) and various alcohols (such as butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether, propylene glycol). Specific examples of these esters include dibutyl adipate, di(2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicoyl sebacate, 2-ethylhexyl diester of linoleic acid dimer, and complex esters formed by reacting 1 mole of sebacate with 2 moles of tetraethylene glycol and 2 moles of 2-ethylhexanoic acid.

[0041] Esters that can be used as synthetic oils also include those from C5 to C6. 12 Those made from monocarboxylic acids and polyols and polyol ethers (such as neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol, and tripentaerythritol).

[0042] Unrefined, refined, and re-refined oils can be used in the compositions of this invention. Unrefined oils are those obtained directly from natural or synthetic sources without further purification. For example, shale oil obtained directly from a dry distillation operation, petroleum obtained directly from distillation, or esterified oil obtained directly from an esterification process and used without further processing are unrefined oils. Refined oils are similar to unrefined oils, except that they have undergone further processing in one or more purification steps to improve one or more properties. Many such purification techniques are known to those skilled in the art, such as distillation, solvent extraction, acid or alkali extraction, filtration, and percolation. Re-refined oils are obtained by applying a process similar to that used to obtain refined oils to used refined oils. Such re-refined oils are also called regenerated oils or reprocessed oils, and are often further processed using techniques for treating waste additives and oil cracking products.

[0043] Other examples of base oils are gas-to-liquid (“GTL”) base oils, which are oils derived from Fischer-Tropsch hydrocarbons produced from syngas containing H2 and CO using a Fischer-Tropsch catalyst. These hydrocarbons typically require further processing to be usable as base oils. For example, they can be hydroisomerized; hydrocracking and hydroisomerizing; dewaxing; or hydroisomerizing and dewaxing by methods known in the art.

[0044] The composition of the base oil depends on the specific application of the lubricating oil composition and is selected by the oil formulator to achieve the desired performance characteristics at a reasonable cost.

[0045] Preferably, the volatility of the lubricating oil or oil blend, as measured by the NOACK test (ASTM D5800), is less than or equal to 20%, more preferably less than or equal to 16%, more preferably less than or equal to 12%, and even more preferably less than or equal to 10%. Preferably, the viscosity index (VI) of the lubricating oil is at least 95, preferably at least 110, more preferably at least 120, even more preferably at least 125, and most preferably about 130-140.

[0046] A lubricating oil composition is formed by providing an oil of lubricating viscosity in a primary amount, combined with minor amounts of additive components (B) and (C) as defined herein, and, if necessary, one or more co-additives such as those described below. This preparation can be carried out by adding the additives directly to the oil or by adding them in their concentrate form to disperse or dissolve the additives. Additives can be added to the oil before, simultaneously with, or after the addition of other additives by any method known to those skilled in the art.

[0047] Preferably, the oil with a lubricating viscosity is present in an amount greater than 65% by mass, more preferably greater than 70% by mass, and even more preferably greater than 75% by mass, based on the total mass of the lubricating oil composition. Preferably, the oil with a lubricating viscosity is present in an amount less than 98% by mass, for example less than 95% by mass, or even less than 90% by mass, based on the total mass of the lubricating oil composition.

[0048] Preferably, the lubricating oil composition of the present invention is a multi-grade oil identified by the viscosity descriptors SAE 20W-X, SAE 15W-X, SAE 10W-X, SAE 5W-X, or SAE 0W-X, wherein X represents any one of 8, 12, 16, 20, 30, 40, and 50; the characteristics of different viscosity grades can be found in the SAE J300 classification system. The lubricating oil composition is preferably in the form of SAE 10W-X, SAE 5W-X, or SAE 0W-X, more preferably in the form of SAE 5W-X or SAE 0W-X, wherein X represents any one of 8, 12, 16, 20, 30, 40, and 50. Preferably, X is 8, 12, 16, or 20.

[0049] Oil-soluble molybdenum compounds (B)

[0050] For the lubricating oil compositions of the present invention, any suitable oil-soluble or oil-dispersible molybdenum compound having friction-improving properties in the lubricating oil composition can be used. Preferably, the oil-soluble or oil-dispersible molybdenum compound is an oil-soluble or oil-dispersible organic molybdenum compound. Examples of such organic molybdenum compounds include molybdenum dithiocarbamate, molybdenum dithiophosphate, molybdenum dithiophosphonate, molybdenum xanthate, molybdenum thioxanthate, molybdenum sulfide, and the like, and mixtures thereof. Particularly preferred are molybdenum dithiocarbamate, dialkyl molybdenum dithiophosphate, alkyl xanthate, and alkyl thioxanthate. A particularly preferred organic molybdenum compound is molybdenum dithiocarbamate. In one embodiment of the invention, the oil-soluble or oil-dispersible molybdenum compound consists of molybdenum dithiocarbamate or molybdenum dithiophosphate or mixtures thereof, serving as the sole source of molybdenum atoms in the lubricating oil composition. In an alternative embodiment of the invention, the oil-soluble or oil-dispersible molybdenum compound consists of molybdenum dithiocarbamate, serving as the sole source of molybdenum atoms in the lubricating oil composition.

[0051] The molybdenum compound can be mononuclear, dinuclear, trinuclear, or tetranuclear. Dinuclear and trinuclear molybdenum compounds are preferred.

[0052] Furthermore, the molybdenum compound may be an acidic molybdenum compound. These compounds will react with a basic nitrogen compound as measured by ASTM test D-664 or D-2896 titration procedures, and are typically hexavalent. Examples include 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, molybdenum can be provided to the compositions of the invention by molybdenum / sulfur complexes of basic nitrogen compounds 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 WO94 / 06897.

[0053] Suitable dinuclear or dimerized dialkyl dithiocarbamate molybdenum is represented by the following formula:

[0054] R1 to R4 independently represent straight-chain, branched, or aromatic hydrocarbon groups containing 1 to 24 carbon atoms; X1 to X4 independently represent oxygen or sulfur atoms. The four hydrocarbon groups, R1 to R4, can be the same or different from each other.

[0055] Other molybdenum compounds that can be used in the compositions of the present invention are organomolybdenum compounds of the following formula: Mo(ROCS2)4 and Mo(RSCS2)4, wherein R is an organic group selected from alkyl, aryl, aralkyl, and alkoxyalkyl groups that typically contain 1-30 carbon atoms, preferably 2-12 carbon atoms, and most preferably 2-12 carbon atoms. Particularly preferred are dialkyl dithiocarbamates of molybdenum.

[0056] Suitable trinuclear organomolybdenum compounds include those of the formula Mo3S k LNQ Z The compounds and their mixtures, wherein L is an independently chosen ligand having an organic group containing a sufficient number of carbon atoms such that the compound is soluble or dispersible in oil, n is 1-4, k varies from 4 to 7, Q is selected from neutral electron-donating compounds such as water, amines, alcohols, phosphine, and ethers, and z is 0-5 and includes non-stoichiometric values. There should be a total of at least 21 carbon atoms, for example at least 25, at least 30, or at least 35 carbon atoms, in the organic groups of all ligands.

[0057] The ligands are independently selected from:

[0058] And mixtures thereof, wherein X, X1, X2, and Y are independently selected from oxygen and sulfur, and wherein R1, R2, and R are independently selected from hydrogen and may be the same or different organic groups. Preferably, the organic group is a hydrocarbon group, such as an alkyl group (e.g., wherein the carbon atom attached to the remainder of the ligand is a primary or secondary carbon), an aryl group, a substituted aryl group, and an ether group. More preferably, each ligand has the same hydrocarbon group.

[0059] Importantly, the organic groups of the ligands contain a sufficient number of carbon atoms to make the compound soluble or dispersible in oil. For example, the number of carbon atoms in each group is typically between about 1 and about 100, preferably between about 1 and about 30, and more preferably between about 4 and about 20. Preferred ligands include dialkyl dithiophosphate, alkyl xanthate, and dialkyl dithiocarbamate, with dialkyl dithiocarbamate being more preferred. Organic ligands containing two or more of the above-described functionalities can also act as ligands and bind to one or more cores. Those skilled in the art will recognize that the formation of the compounds of the present invention requires the selection of ligands with suitable charges to balance the core charge.

[0060] Mo3S k L n Q z The compound has a cationic core surrounded by anionic ligands and is represented by the following structure, having a net charge of +4: and

[0061] Therefore, for these cores to be solubilized, the total charge in all ligands must be -4. Four monoanion ligands are preferred. Without being bound by any theory, it is believed that two or more trinuclear cores can be bonded or interconnected by one or more ligands, and these ligands can be multidentate. This includes cases where multidentate ligands have multiple connections to a single core. It is believed that oxygen and / or selenium can replace sulfur in the core.

[0062] Oil-soluble or oil-dispersible trinuclear molybdenum compounds can be dissolved in suitable liquids / solvents, such as (NH4)2Mo3S. 13 Molybdenum compounds can be prepared by reacting a molybdenum source such as n(H₂O) (where n is between 0 and 2 and includes non-stoichiometric values) with a suitable ligand source such as tetraalkylthiuram disulfide. Other oil-soluble or dispersible trinuclear molybdenum compounds can be prepared in a suitable solvent(one or more) with a molybdenum source (e.g., (NH₄)₂Mo₃S). 13 It is formed during the reaction of ·n(H2O)), a ligand source (e.g., tetraalkylthiuram disulfide, dialkyl dithiocarbamate, or dialkyl dithiophosphate), and a sulfur abstracting agent (e.g., cyanide ion, sulfite ion, or substituted phosphine). Alternatively, trinuclear molybdenum-sulfur halide salts such as [M']2[Mo3S7A6] (where M' is the counterion and A is a halogen, such as Cl, Br, or I) can react with a ligand source, such as dialkyl dithiocarbamate or dialkyl dithiophosphate, in a suitable liquid / solvent to form an oil-soluble or dispersible trinuclear molybdenum compound. Suitable liquids / solvents can be, for example, aqueous or organic.

[0063] The oil solubility or dispersibility of a compound may be affected by the number of carbon atoms in the organic groups of the ligands. Preferably, there should be a total of at least 21 carbon atoms in the organic groups of all ligands. Preferably, the selected ligand source has a sufficient number of carbon atoms in its organic groups to make the compound soluble or dispersible in the lubricating oil composition.

[0064] The lubricating oil composition of the present invention contains the molybdenum compound in an amount of 600-1500 ppm, preferably 600-1200 ppm or even 700-1000 ppm molybdenum (ASTM D5185) to provide the composition.

[0065] Detergent composition (C)

[0066] Metal detergents serve both as cleaning agents to reduce or remove deposits and as acid neutralizers or rust inhibitors, thereby reducing wear and corrosion and extending engine life. Detergents typically consist of a polar head with a long, hydrophobic tail, and the polar head contains a metal salt of an acidic organic compound. This salt may contain substantially stoichiometric amounts of metal; in this case, they are often referred to as normal or neutral salts and typically have a total base number, or TBN, of 0–80 mg KOH / g (measurable via ASTM D2896). Large amounts of metal base can be introduced by reacting an excess of a metal compound (such as an oxide or hydroxide) with an acidic gas (such as carbon dioxide). The resulting over-alkaline detergent comprises a neutralized detergent as an outer layer of metal base (e.g., carbonate) micelles. Such over-alkaline detergents can have a TBN of 150 mg KOH / g or greater, and typically have a TBN of 250 to 450 mg KOH / g or higher.

[0067] According to the present invention, the lubricating oil composition comprises a detergent composition comprising at least one magnesium sulfonate detergent.

[0068] The detergent compositions of the present invention may contain one or more additional detergent additives. Suitable additional detergents include oil-soluble neutral and superalkaline sulfonates, phenolates, thiophosphonates, thiophosphonates, salicylates, and naphthenates of metals, especially alkali metals or alkaline earth metals (e.g., sodium, potassium, lithium, calcium, and magnesium), as well as other oil-soluble carboxylates. Additionally, the additional detergent additives may contain hybrid detergents comprising any combination of sodium, potassium, lithium, calcium, or magnesium sulfonates, phenolates, thiophosphonates, salicylates, and naphthenates.

[0069] Preferably, one or more additional detergent additives of the present invention comprise calcium and / or magnesium metal salts. More preferably, the one or more additional detergent additives are selected from magnesium salicylate, calcium salicylate, calcium sulfonate, magnesium phenolate, calcium phenolate, mixed detergents comprising two or more of these additional detergent additives, and / or combinations thereof.

[0070] In a preferred embodiment, the one or more additional detergent additives are calcium salicylate and / or calcium sulfonate, with calcium salicylate being the most preferred. Most preferably, the detergent composition comprises a combination of one or more magnesium sulfonate detergents and one or more calcium salicylate detergents.

[0071] If present, any calcium detergent is suitably present in an amount sufficient to provide at least 500 ppm, preferably at least 750, more preferably at least 900 ppm of atomic calcium to the lubricating oil composition (ASTM D5185). If present, any calcium detergent is suitably present in an amount sufficient to provide no more than 4000 ppm, preferably no more than 4000, more preferably no more than 2000 ppm of atomic calcium to the lubricating oil composition (ASTM D5185). If present, any calcium detergent is suitably present in an amount sufficient to provide 500-4000 ppm, preferably 750-3000 ppm, more preferably 900-2000 ppm of atomic calcium to the lubricating oil composition (ASTM D5185).

[0072] The magnesium detergent of all aspects of this invention can be a neutral salt or a superalkaline salt. Suitably, the magnesium detergent of this invention is a superalkaline magnesium sulfonate having 80-500 mg KOH / g TBN (ASTM D2896).

[0073] The magnesium detergent of the present invention provides 200-4000 ppm magnesium atoms, suitably 200-2000 ppm, 300-1500 or 450-1200 ppm magnesium atoms (ASTM D5185) to its lubricating oil composition.

[0074] Suitably, the total atomic weight of metals in the detergent composition according to all aspects of the invention is not more than 5000 ppm, preferably not more than 4000 ppm, more preferably not more than 2000 ppm (ASTM D5185). Suitably, the total atomic weight of metals in the detergent composition according to all aspects of the invention is at least 500 ppm, preferably at least 800 ppm, more preferably at least 1000 ppm (ASTM D5185). Suitably, the total atomic weight of metals in the detergent composition according to all aspects of the invention is 500-5000 ppm, preferably 500-3000 ppm, more preferably 500-2000 ppm (ASTM D5185).

[0075] Sulfonate detergents can be prepared from sulfonic acids, which are typically obtained by sulfonation of alkyl-substituted aromatic hydrocarbons (e.g., those obtained by fractionation of petroleum or by alkylation of aromatic hydrocarbons). Examples include those obtained by alkylation of benzene, toluene, xylene, naphthalene, biphenyl, or their halogen derivatives such as chlorobenzene, chlorotoluene, and chloronaphthalene. Alkylation can be carried out in the presence of a catalyst, wherein the alkylating agent has about 3 to more than 70 carbon atoms. Alkyl aryl sulfonates typically contain about 9 to about 80 or more carbon atoms for each alkyl-substituted aromatic moiety, preferably about 16 to about 60 carbon atoms. Oil-soluble sulfonates or alkyl aryl sulfonic acids can be neutralized with metal oxides, hydroxides, alkoxides, carbonates, carboxylates, sulfides, hydrosulfides, nitrates, borates, and ethers. The amount of metal compound is selected based on the desired TBN of the final product, but is typically about 100-220% by mass (preferably at least 125% by mass) of the stoichiometric amount required.

[0076] Phenols and metal salts of thiophenols are prepared by reaction with suitable metal compounds such as oxides or hydroxides, and neutral or superbasic products can be obtained by methods well known in the art. Thiophenols can be prepared by reacting phenols with sulfur or sulfur-containing compounds such as hydrogen sulfide, sulfur monohalides, or sulfur dihalides to form products, which are typically mixtures of compounds in which two or more phenols are bridged by sulfur-containing bridging groups.

[0077] Carboxylate detergents, such as salicylates, can be prepared by reacting an aromatic carboxylic acid with a suitable metal compound such as an oxide or hydroxide, and neutral or superbasic products can be obtained by methods well known in the art. The aromatic moiety of the aromatic carboxylic acid may contain heteroatoms, such as nitrogen and oxygen. Preferably, the moiety contains only carbon atoms; more preferably, the moiety contains six or more carbon atoms; benzene, for example, is a preferred moiety. The aromatic carboxylic acid may contain one or more aromatic moieties, such as one or more benzene rings, which are fused or linked via alkylene bridges.

[0078] Preferred substituents in oil-soluble salicylic acids are alkyl substituents. In alkyl-substituted salicylic acids, the alkyl group advantageously contains 5-100, preferably 9-30, and particularly 14-20 carbon atoms. When more than one alkyl group is present, the average number of carbon atoms in all alkyl groups is preferably at least about 9 to ensure sufficient oil solubility.

[0079] Suitablely, the ratio of detergent atomic metal to atomic molybdenum in the lubricating oil composition of all aspects of the present invention is less than 3, preferably less than 2.

[0080] Oil-soluble boron-containing compounds (D)

[0081] Oil-soluble or oil-dispersible boron-containing compounds can be any conventional borate lubricant additive. Preferably, the oil-soluble boron-containing compound is a borate dispersant, borate ester, or borate detergent.

[0082] Suitablely, boron-containing compounds include borate dispersants, particularly borate ashless (i.e., metal-free) dispersants. Preferred ashless borate dispersants are borate polyisobutylene succinimide dispersants.

[0083] Dispersants are typically “ashless,” unlike metallic and therefore ash-forming materials, they are non-metallic organic materials that produce virtually no ash when burned. They comprise long hydrocarbon chains (e.g., hydrocarbon polymer backbones) with polar heads, the polarity derived from the inclusion of, for example, O, P, or N atoms. Typically, such dispersants have amine, alcohol-alcohol, or amide polar structural moieties usually linked to the hydrocarbon chain via bridging groups. The hydrocarbon chain is a lipophilic group that imparts oil solubility and has, for example, 40-500 carbon atoms. Thus, ashless dispersants can comprise oil-soluble polymer backbones. Suitable ashless dispersants can be, for example, oil-soluble salts, esters, amino-esters, amides, imides, and oxazolines selected from long-chain hydrocarbon-substituted monocarboxylic acids and polycarboxylic acids or their anhydrides; thiocarboxylic acid ester derivatives of long-chain hydrocarbons; long-chain aliphatic hydrocarbons having polyamine structural moieties directly attached thereto; and Mannich condensation products formed by condensing long-chain substituted phenols with formaldehyde and polyalkylene polyamines.

[0084] Preferably, all dispersants used (including all nitrogen-containing dispersants and any nitrogen-free dispersants) are derived from hydrocarbon polymers having an average number-average molecular weight (Mn) of about 600-3000, more preferably 700-2700, and even more preferably 700-2500.

[0085] Highly preferred ashless dispersants include dispersants derived from polyolefin-substituted mono- or dicarboxylic acids, anhydrides, or esters, with most preferably dispersants derived from polyisobutylene-substituted mono- or dicarboxylic acids, anhydrides, or esters.

[0086] Suitable hydrocarbons or polymers used in dispersant formation include homopolymers, interpolymers, or low molecular weight hydrocarbons. One class of such polymers includes ethylene and / or at least one having the formula H₂C=CHR. 1 C3-C 28 Polymers of α-olefins, wherein R 1 It is a straight-chain or branched alkyl group containing 1-26 carbon atoms, and said polymer contains carbon-carbon unsaturated, preferably highly terminal vinylidene unsaturated moieties. Preferably, such polymers comprise interpolymers of ethylene and at least one α-olefin of the above formula, wherein R 1The alkyl group contains 1-18 carbon atoms, more preferably 1-8 carbon atoms, and even more preferably 1-2 carbon atoms. Therefore, useful α-olefin monomers and comonomers include, for example, propylene, but-1-ene, hex-1-ene, oct-1-ene, 4-methylpentane-1-ene, decane-1-ene, dodecane-1-ene, tridecane-1-ene, tetradecane-1-ene, pentadecane-1-ene, hexadecane-1-ene, heptadecane-1-ene, octadecane-1-ene, nonadecaneane-1-ene, and mixtures thereof (e.g., mixtures of propylene and but-1-ene, and the like). Examples of such polymers are propylene homopolymers, but-1-ene homopolymers, ethylene-propylene copolymers, ethylene-butane copolymers, propylene-butene copolymers, and the like, wherein said polymers contain at least some terminal and / or internal unsaturations. Preferred polymers are unsaturated copolymers of ethylene and propylene and unsaturated copolymers of ethylene and butane. The interpolymer may contain a small amount, for example, 0.5-5 mol% of C4-C. 18 Non-conjugated diene comonomers. However, it is preferred that the polymer comprises only α-olefin homopolymers, interpolymers of α-olefin comonomers, and interpolymers of ethylene and α-olefin comonomers. The molar ethylene content of the polymer used is preferably in the range of 0-80%, more preferably 0-60%. When propylene and / or but-1-ene are used as one or more comonomers with ethylene, the ethylene content of such copolymers is most preferably 15-50%, but higher or lower ethylene contents are possible.

[0087] Another class of useful polymers are those prepared by cationic polymerization of isobutylene, styrene, and the like. Commonly used polymers in this class include polyisobutylene obtained by polymerizing a C4 refinery stream having a butene content of about 35 to about 75 wt% and an isobutylene content of about 30 to about 60 wt% in the presence of a Lewis acid catalyst such as aluminum trichloride or boron trifluoride. Preferred sources of monomers for preparing poly-n-butene are petroleum feedstock streams, such as residual oil II. These feedstocks are disclosed in the art, for example, in U.S. Patent No. 4,952,739. Polyisobutylene (PIB) is the most preferred backbone of the invention because it can be readily obtained by cationic polymerization of a butene stream (e.g., using an AlCl3 or BF3 catalyst). Such polyisobutylenes generally contain residual unsaturations arranged along the polymer chain in an amount of about one olefinic double bond / polymer chain. In some embodiments, the polyolefinic structural portion of the dispersant comprises highly reactive polyisobutylene (HR-PIB) having a terminal vinylidene content of at least 65%, for example, 70%, more preferably at least 80%, and most preferably at least 85%. Preparation of such polymers is described, for example, in U.S. Patent No. 4,152,499. HR-PIB is known and can be traded under the name Glissopal. TM (From BASF) and Ultravis TM Purchased from BP.

[0088] The hydrocarbon or polymer backbone can be functionalized, for example, by selectively functionalizing carbon-carbon unsaturated sites on the polymer or hydrocarbon chain with structural moieties that produce carboxylic acids (preferably acid or anhydride structural moieties), or by randomly functionalizing along the chain in any order using any of the three methods described above or a combination thereof.

[0089] The most preferred dispersant is one comprising at least one polyalkenyl succinimide, particularly a polyisobutylene succinimide, which is a reaction product of a polyalkenyl-substituted succinic anhydride (e.g., PIBSA) and a polyamine (PAM). In other words, the most preferred borate dispersant comprises borate-treated polyalkenyl-substituted succinic anhydride (e.g., PIBSA) and a polyamine (PAM). Preferably, such dispersants have a coupling ratio of about 0.65 to about 1.25, more preferably about 0.8 to about 1.1, and most preferably about 0.9 to about 1. Within the scope of this disclosure, "coupling ratio" can be defined as the ratio of the number of succinyl groups in the PIBSA to the number of primary amine groups in the polyamine reactant.

[0090] Another class of high molecular weight ashless dispersants includes Mannich base condensation products. Typically, these products are prepared, for example, as disclosed in U.S. Patent 3,442,808, by condensing approximately 1 mole of a long-chain alkyl-substituted monohydroxy or polyhydroxybenzene with approximately 1 to 2.5 moles of one or more carbonyl compounds (e.g., formaldehyde and oligooxymethylene) and approximately 0.5 to 2 moles of polyalkylene polyamines. These Mannich base condensation products can include polymer products from metallocene-catalyzed polymerization reactions as substituents on the phenyl group, or can be reacted with compounds containing such polymers substituted on succinic anhydride, in a manner similar to that described in U.S. Patent No. 3,442,808. Examples of functionalized and / or derived olefin polymers synthesized using metallocene catalyst systems are described in the aforementioned publications.

[0091] The dispersant(s) of the present invention are preferably non-polymeric (e.g., mono- or bis-succinimide). More preferably, the dispersant contributes a total of about 0.10 to about 0.20 wt%, preferably about 0.115 to about 0.18 wt%, and most preferably about 0.12 to about 0.16 wt% of nitrogen to the lubricating oil composition.

[0092] Dispersants can be boronized by conventional methods, as generally taught in U.S. Patent Nos. 3,087,936, 3,254,025, and 5,430,105. Boronization of dispersants containing acyl nitrogen can be readily achieved by treating them with boron compounds, such as boron oxide, boron halide, boric acid, and esters of boric acid, in an amount sufficient to provide approximately 0.1 to approximately 20 atomic proportions of boron per mole of acylated nitrogen composition.

[0093] Boron (which appears in the product as a dehydrated boric acid polymer (mainly (HBO2)3)) is thought to be linked with dispersant imides and diimides as amine salts, such as metaborates of diimides. Boration can be carried out as follows: a sufficient amount of a boron compound, preferably boric acid (usually in the form of a slurry), is added to the acyl nitrogen compound and heated with stirring at about 135°C to about 190°C, for example 140°C-170°C, for about 1 to about 5 hours, followed by nitrogen stripping. Alternatively, boron treatment can be carried out by adding boric acid to a hot reaction mixture of a dicarboxylic acid material and an amine while simultaneously removing water. Other post-reaction methods known in the art can also be applied.

[0094] Non-dispersant boron compounds include boron oxide, boron oxide hydrate, boron trioxide, boron trifluoride, boron tribromide, boron trichloride, boron-containing acids such as organoboronic acid, boric acid, tetraboric acid, and metaboric acid, borohydrides, boronamides, and various esters of boronic acids. Suitable "non-dispersant boron sources" can include any oil-soluble boron-containing compound, but preferably include one or more boron-containing additives known to impart enhanced properties to lubricating oil compositions. Such boron-containing additives include, for example, boronized dispersant VI modifiers; alkali metal, mixed alkali metal, or alkaline earth metal borates; boronized perbasic metal detergents; boronized epoxides; boron esters; and boron ester amides.

[0095] Alkali metal and alkaline earth metal borates are generally hydrated, particulate metal borates known in the art. Alkali metal borates include mixed alkali metal and alkaline earth metal borates. These metal borates are commercially available. Representative patents describing suitable alkali metal and alkaline earth metal borates and methods of their manufacture include U.S. Patent Nos. 3,997,454; 3,819,521; 3,853,772; 3,907,601; 3,997,454 and 4,089,790.

[0096] Boronized amines can be prepared by reacting one or more of the above-mentioned boron compounds with one or more aliphatic amines, such as amines containing four to eighteen carbon atoms. They can be prepared by reacting amines with boron compounds at a temperature of 50-300°C, preferably 100-250°C, at an amine to boron compound equivalent ratio of 3:1 to 1:3.

[0097] Boronized aliphatic epoxides are generally the reaction products of one or more of the aforementioned boron compounds with at least one epoxide. The epoxide is generally an aliphatic epoxide having 8-30, preferably 10-24, and more preferably 12-20 carbon atoms. Examples of useful aliphatic epoxides include heptyl epoxides and octyl epoxides. Mixtures of epoxides may also be used, such as commercial mixtures of epoxides having 14-16 and 14-18 carbon atoms. Boronized aliphatic epoxides are generally known and described in U.S. Patent 4,584,115.

[0098] Boron esters can be prepared by reacting one or more of the aforementioned boron compounds with one or more alcohols having suitable lipophilicity. Typically, the alcohols contain 6-30 or 8-24 carbon atoms. Methods for preparing such boron esters are known in the art.

[0099] Borate esters can be borate phospholipids. Such compounds and methods for their preparation are described in EP-A-0684 298. Borate-treated alkaline metal detergents are known in the art, wherein the borate partially or wholly replaces the carbonate in the core.

[0100] In one embodiment of the invention, the boronized ashless dispersant defined herein represents the only boron-containing compound in the lubricating oil composition.

[0101] The boron-containing compound introduces more than 200, preferably more than 250 ppm of boron into the lubricating oil composition, based on the total mass of the lubricating oil composition (ASTM D5185). The boron-containing compound introduces less than 600, preferably less than 500, and even more preferably less than 400 ppm of boron into the lubricating oil composition, based on the total mass of the lubricating oil composition (ASTM D5185).

[0102] Co-additives

[0103] The lubricating oil compositions according to each aspect of the invention may additionally contain one or more co-additives, which are different from additive components (B), (C), and (D). Suitable co-additives and their typical treatment rates will be discussed below. All listed values ​​are given as a percentage by mass of active ingredient in a fully formulated lubricant.

[0104]

[0105] (1) Viscosity improvers are only used for multi-grade oils.

[0106] The final lubricating oil composition (typically prepared by blending the additive or each additive into a base oil) may contain 5-25, preferably 5-18, typically 7-15% by mass of co-additives, with the remainder being an oil of lubricating viscosity.

[0107] The co-additives described above are discussed in further detail below; as is known in the art, some additives can provide multiple effects, for example, a single additive can act as a dispersant and as an oxidation inhibitor.

[0108] anti-wear agent Reducing friction and excessive wear is typically based on compounds containing sulfur or phosphorus, or both, which, for example, can deposit polysulfide films on the surface in question. Of particular note are dialkyl dithiophosphate metal salts, where the metal can be an alkali metal or an alkaline earth metal, or aluminum, lead, tin, molybdenum, manganese, nickel, copper, or preferably zinc.

[0109] Dialkyl dithiophosphate metal salts can be prepared using known techniques as follows: First, dialkyl dithiophosphate (DDPA) is formed, typically by reacting one or more alcohols or phenols with P2S5, followed by neutralization of the formed DDPA with a metal compound. For example, dithiophosphate can be produced by reacting a mixture of primary and secondary alcohols. Alternatively, multiple dithiophosphates can be prepared, where the hydrocarbon groups on one dithiophosphate are entirely secondary hydrocarbon groups, and the hydrocarbon groups on the others are entirely primary hydrocarbon groups. Any basic or neutral metal compound can be used to produce the metal salt, but oxides, hydroxides, and carbonates are most commonly used. Commercially available additives often contain an excess of metal due to the use of an excess of basic metal compound in the neutralization reaction.

[0110] The preferred zinc dihydrodithiophosphate (ZDDP) is an oil-soluble salt of dihydrodithiophosphate and can be represented by the following formula:

[0111] R and R' can be the same or different hydrocarbon groups containing 1 to 18, preferably 2 to 12, carbon atoms, and include groups such as alkyl, alkenyl, aryl, aralkyl, alkylaryl, and alicyclic groups. Alkyl groups containing 2 to 8 carbon atoms are particularly preferred as R and R' groups. Therefore, these groups can be, for example, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, pentyl, n-hexyl, isohexyl, n-octyl, decyl, dodecyl, octadecyl, 2-ethylhexyl, phenyl, butylphenyl, cyclohexyl, methylcyclopentyl, propenyl, and butenyl. To obtain oil solubility, the total number of carbon atoms in dithiophosphate (i.e., R and R') is generally about 5 or higher. Dialkyl zinc dithiophosphate can therefore include dialkyl zinc dithiophosphate.

[0112] ZDDP is added to the lubricating oil composition in an amount sufficient to provide no more than 1200 ppm by mass, preferably no more than 1000 ppm, more preferably no more than 900 ppm, and most preferably no more than 850 ppm by mass of phosphorus, based on the total mass of the lubricating oil composition and measured according to ASTM D5185. ZDDP is also suitably added to the lubricating oil composition in an amount sufficient to provide at least 200 ppm by mass, preferably at least 350 ppm, more preferably at least 500 ppm by mass of phosphorus, based on the total mass of the lubricating oil composition and measured according to ASTM D5185.

[0113] The ratio of phosphorus to molybdenum in the lubricating oil composition according to all aspects of the invention is suitably less than 1.5, preferably less than 1.2, and more preferably less than 1.0.

[0114] Examples of ashless anti-wear agents include 1,2,3-triazole, benzotriazole, sulfurized fatty acid esters, and dithiocarbamate derivatives.

[0115] Ashless dispersant The dispersant comprises an oil-soluble polymeric hydrocarbon skeleton having functional groups capable of associating with the particles to be dispersed and may be used in addition to any boron-containing compound (D) optionally present in the lubricating oils of any aspect of the invention. Typically, the dispersant comprises a polar structural portion of an amine, alcohol, amide, or ester generally linked to the polymeric skeleton via a bridging group. The ashless dispersant may, for example, be selected from oil-soluble salts, esters, amino esters, amides, imides, and oxazolines of long-chain hydrocarbon-substituted monocarboxylic acids and dicarboxylic acids or their anhydrides; thiocarboxylic acid ester derivatives of long-chain hydrocarbons; long-chain aliphatic hydrocarbons having a polyamine directly attached thereto; and Mannich reaction products formed by the condensation of long-chain substituted phenols with formaldehyde and polyalkylene polyamines.

[0116] Ashless friction modifier For example, nitrogen-free organic friction modifiers can be used in the lubricant compositions of the present invention and are generally known and include esters formed by reacting carboxylic acids and anhydrides with alkanols. Other useful friction modifiers generally include polar end groups (e.g., carboxyl or hydroxyl groups) covalently bonded to lipophilic hydrocarbon chains. Esters of carboxylic acids and anhydrides with alkanols are described in US 4,702,850. Examples of other conventional organic friction modifiers are described by M. Belzer in "Journal of Tribology" (1992), Vol. 114, pp. 675-682 and by M. Belzer and S. Jahanmir in "Lubrication Science" (1988), Vol. 1, pp. 3-26.

[0117] Preferred organic ashless and nitrogen-free friction modifiers are esters or ester-based; particularly preferred organic ashless and nitrogen-free friction modifiers are glyceryl monooleate (GMO).

[0118] Ashless amines or amine-based friction modifiers, including oil-soluble alkoxylated mono- and di-amines, can also be used to improve boundary layer lubrication. A commonly used class of such metal-free, nitrogen-containing friction modifiers includes ethoxylated alkylamines. They can be in the form of adducts or reaction products with boron compounds such as boron oxide, boron halide, metaborate, boric acid, or mono, di, or trialkyl borate esters. Another type of metal-free, nitrogen-containing friction modifier is an ester formed as a reaction product of: (i) a tertiary amine of formula R1R2R3N, wherein R1, R2, and R3 represent an aliphatic hydrocarbon group, preferably alkyl, containing 1-6 carbon atoms, and at least one of R1, R2, and R3 has a hydroxyl group; and (ii) a saturated or unsaturated fatty acid containing 10-30 carbon atoms. Preferably, at least one of R1, R2, and R3 is an alkyl group. Preferably, the tertiary amine has at least one hydroxyalkyl group containing 2-4 carbon atoms. The ester can be a mono-, di-, or tri-ester, or a mixture thereof, depending on how many hydroxyl groups are available for acyl esterification with the fatty acid. Preferred embodiments comprise a mixture of esters formed as reaction products of: (i) a hydroxy tertiary amine of formula R1R2R3N, wherein R1, R2, and R3 can be C2-C4 hydroxyalkyl; (ii) a saturated or unsaturated fatty acid containing 10-30 carbon atoms, wherein the mixture of esters formed comprises at least 30-60% by mass, preferably 45-55% by mass, of a diester, for example, 50% by mass; 10-40% by mass, preferably 20-30% by mass, of a monoester, for example, 25% by mass; and 10-40% by mass, preferably 20-30% by mass, for example, of a triester. Suitably, the ester is a mono-, di-, or tri-carboxylic acid ester of triethanolamine and a mixture thereof.

[0119] Typically, the total amount of additional organic ashless friction modifiers in the lubricant according to the invention does not exceed 5% by mass, preferably not more than 2% by mass, and more preferably not more than 0.5% by mass, based on the total mass of the lubricating oil composition. In one embodiment of the invention, the lubricating oil composition does not contain other organic ashless friction modifiers.

[0120] Viscosity modifier (VM) It is used to impart high and low temperature operability to lubricating oils. The VM used can have that single function or can be multifunctional. Multifunctional viscosity modifiers, also known as dispersants, are also known. Suitable viscosity modifiers are copolymers of polyisobutylene, ethylene and propylene and higher α-olefins, polymethacrylates, polyalkyl methacrylates, methacrylate copolymers, copolymers of unsaturated dicarboxylic acids and vinyl compounds, copolymers of styrene and acrylates, and partially hydrogenated styrene / isoprene copolymers, partially hydrogenated styrene / butadiene copolymers and partially hydrogenated isoprene / butadiene copolymers, as well as partially hydrogenated butadiene and isoprene / divinylbenzene homopolymers.

[0121] antioxidants (Sometimes called oxidation inhibitors) enhance the antioxidant properties of a composition and can act by combining with and modifying peroxides to render them harmless by decomposing them or by inertizing oxidation catalysts. Oxidative deterioration can manifest as sludge in lubricants, varnish-like deposits on metal surfaces, and increased viscosity.

[0122] Examples of suitable antioxidants are selected from copper-containing antioxidants, sulfur-containing antioxidants, aromatic amine-containing antioxidants, hindered phenolic antioxidants, dithiophosphate derivatives, and metal thiocarbamate salts. Preferred antioxidants are aromatic amine-containing antioxidants, hindered phenolic antioxidants, and mixtures thereof. In a preferred embodiment, the antioxidant is present in the lubricating oil composition of the present invention.

[0123] It can be used Rust inhibitor It is selected from nonionic polyoxyethylene polyols and their esters, polyoxyethylene phenols and anionic alkyl sulfonic acids.

[0124] Corrosion inhibitors containing copper and lead These compounds can be used in some embodiments of the invention, and when included in the lubricating composition, they are preferably present in an amount not exceeding 0.2 wt% of the active ingredient. However, in a preferred embodiment of the invention, no copper-containing additives are present in the lubricating oil composition. When present, suitable compounds of this kind are thiadiazole polysulfides containing 5-50 carbon atoms, their derivatives, and their polymers. Derivatives of 1,3,4-thiadiazole, such as those described in U.S. Patent Nos. 2,719,125; 2,719,126, and 3,087,932, are typical. Other similar materials are described in U.S. Patent Nos. 3,821,236; 3,904,537; 4,097,387; 4,107,059; 4,136,043; 4,188,299, and 4,193,882. Other additives are thiodiazole and polythiosulfinamides, such as those described in British Patent Specification No. 1,560,830. Benzotriazole derivatives also belong to this category of additives.

[0125] A small amount can be used Demulsifying components Preferred demulsifying components are described in EP 330522. They are obtained by reacting an olefin oxide with an adduct obtained through the reaction of a diepoxide with a polyol. The demulsifier should be used at a level not exceeding 0.1% by mass of the active ingredient. A treatment rate of 0.001-0.05% by mass of the active ingredient is suitable.

[0126] Pour point depressantAlso known as lubricating oil flow improvers, these additives lower the minimum temperature at which a fluid can flow or be poured. Such additives are well-known. Typical additives that improve the low-temperature flowability of fluids include fumaric acid (C8 to C4). 18 Dialkyl ester / vinyl acetate copolymer, polymethyl methacrylate, etc.

[0127] Foam control can be provided by many compounds, including polysiloxane defoamers, such as silicone oil or polydimethylsiloxane.

[0128] Various individual additives can be introduced into the base oil in any convenient manner. Therefore, each component can be added directly to the base oil or base oil blend as follows: dispersed or dissolved in the base oil or base oil blend at the desired concentration level. This blending can be carried out at ambient temperature or high temperature.

[0129] Preferably, all additives except viscosity improvers and pour point depressants are blended into a concentrate or additive package, described herein as an additive package, and then blended into a base oil to prepare the finished lubricant. The concentrate is typically formulated to contain an appropriate amount of one or more additives, sufficient to provide the desired concentration in the final formulation when the concentrate is combined with a predetermined amount of base lubricant.

[0130] Preferably, the concentrate is prepared according to the method described in US 4,938,880. This patent describes the preparation of a premix of ashless dispersant and metal detergent by pre-blending at a temperature of at least about 100°C. The premix is ​​then cooled to at least 85°C and additional components are added.

[0131] The final crankcase lubricant formulation may contain 2 to 20% by mass, preferably 4 to 18% by mass, and most preferably 5 to 17% by mass of concentrate or additives, with the remainder being base oil.

[0132] The lubricating oil compositions of the present invention may have a sulfate ash content of less than or equal to 1.2%, preferably less than or equal to 1.1%, more preferably less than or equal to 1.0% by mass (ASTM D874), based on the total mass of the composition. The lubricating oil compositions of the present invention suitably have a sulfate ash content of at least 0.2%, preferably at least 0.4%, for example at least 0.5% by mass (ASTM D874), based on the total mass of the composition. Suitably, the sulfate ash content of the lubricating oil composition is in the range of 0.04-1.2% by mass, preferably 0.05-1.0% by mass (ASTM D874).

[0133] The phosphorus content in the lubricating oil composition of the present invention depends on the specific application of the oil. Suitably, the lubricating oil composition contains phosphorus in an amount of less than or equal to 0.12% by mass, preferably up to 0.1% by mass, more preferably less than or equal to 0.09% by mass, and even more preferably less than or equal to 0.08% by mass (ASTM D5185), based on the total mass of the composition. Suitably, the lubricating oil composition contains phosphorus in an amount of greater than or equal to 0.01%, preferably greater than or equal to 0.02%, more preferably greater than or equal to 0.03%, and even more preferably greater than or equal to 0.05% by mass (ASTM D5185), based on the total mass of the composition.

[0134] The sulfur content in a lubricating oil composition depends on the specific application of the composition. A lubricating oil composition may contain sulfur in an amount of up to 0.4%, for example, up to 0.35% by mass of sulfur (ASTM D2622), based on the total mass of the composition. Generally, a lubricating oil composition contains at least 0.1%, or even at least 0.2% by mass of sulfur (ASTM D2622), based on the total mass of the composition.

[0135] The nitrogen content in the lubricating oil composition according to the invention depends on the specific application of the oil. Typically, the lubricating oil composition according to the invention contains at least 0.02, for example, at least 0.03 or 0.04% nitrogen by mass, based on the total mass of the composition and measured according to ASTM D5291. Suitably, the lubricating oil composition contains no more than 0.20, for example, no more than 0.15 or no more than 0.12% nitrogen by mass, based on the total mass of the composition and measured according to ASTM D5291.

[0136] Suitablely, the lubricating oil compositions of all aspects and embodiments of the present invention may have a total base number (TBN) of 4-15, preferably 5-12 mg KOH / g, as measured according to ASTM D2896.

[0137] By way of example, the present invention relates to the following embodiments: 1. A crankcase lubricating oil composition comprising or prepared by mixing the following components: (A) The main amount of lubricating viscosity oil; (B) To provide the lubricating oil composition with an oil-soluble or oil-dispersible molybdenum-containing additive containing 600-1500 ppm of molybdenum atoms. (C) A detergent composition containing one or more magnesium sulfonates, providing the lubricating oil composition with an amount of 200-4000 ppm magnesium atoms as measured according to ASTM D5185, and (D) An oil-soluble or oil-dispersible boron compound present in the lubricating oil composition in an amount sufficient to provide 200-600 ppm boron atoms as determined according to ASTM D5185.

[0138] 2. The lubricating oil composition according to embodiment 1, wherein the detergent composition comprises one or more additional detergent additives selected from magnesium salicylate, calcium salicylate, calcium sulfonate, magnesium phenolate, calcium phenolate, mixed detergents containing two or more of these additional detergent additives and / or combinations thereof.

[0139] 3. The lubricating oil composition according to embodiment 2, wherein the detergent composition further comprises calcium salicylate and / or calcium sulfonate detergents.

[0140] 4. The lubricating oil composition according to embodiment 3, wherein the detergent composition comprises one or more magnesium sulfonate detergents and one or more calcium salicylate detergents.

[0141] 5. The lubricating oil composition according to embodiment 3 or 4, wherein the calcium-containing detergent is present in an amount sufficient to provide the lubricating oil composition with 500-4000 ppm, preferably 750-3000 ppm, more preferably 900-2000 ppm of atomic calcium as measured according to ASTM D5185.

[0142] 6. A method for lubricating a spark-ignition or compression-ignition internal combustion engine, comprising lubricating the engine with a lubricating oil composition as defined in any of the above embodiments.

[0143] 7. The use of a magnesium-containing detergent in the crankcase lubricating oil composition to reduce boundary friction measurements in the lubricating oil composition by providing an amount of 200-4000 ppm magnesium as measured according to ASTM D5185, the reduction being compared to an equivalent lubricant that does not contain an amount of the magnesium-containing detergent sufficient to provide 200-4000 ppm magnesium to the lubricating oil composition.

[0144] 8. According to the use of embodiment 7, the magnesium-containing detergent is one or more magnesium sulfonate detergents.

[0145] 9. According to the application of embodiment 7 or 8, the lubricating oil composition further comprises an oil-soluble or oil-dispersible molybdenum-containing additive to provide 600-1500 ppm molybdenum atoms (ASTM D5185) to the lubricating oil composition.

[0146] 10. According to the application of embodiment 7, 8 or 9, the lubricating oil composition further comprises an oil-soluble or oil-dispersible boron-containing additive to provide 200-600 ppm boron atoms (ASTM D5185) to the lubricating oil composition.

[0147] 11. According to the use of any one of embodiments 7-10, wherein the detergent composition further comprises one or more additional detergent additives selected from magnesium salicylate, magnesium phenolate, calcium salicylate, calcium phenolate and / or calcium sulfonate.

[0148] 12. The use according to any one of embodiments 7-11, wherein the detergent composition comprises one or more magnesium sulfonate detergents and one or more calcium-containing detergents.

[0149] 13. The lubricating oil composition according to embodiment 12, wherein the detergent composition comprises one or more magnesium sulfonate detergents and one or more calcium salicylate detergents.

[0150] 14. As used according to embodiment 12 or 13, wherein the calcium-containing detergent is present in an amount sufficient to provide the lubricating oil composition with 500-4000 ppm, preferably 750-3000 ppm, more preferably 900-2000 ppm of atomic calcium as measured according to ASTM D5185.

[0151] 15. The use of a lubricating oil composition according to any one of embodiments 1-6 in the crankcase lubrication of a spark-ignition or compression-ignition internal combustion engine to reduce the coefficient of friction between metal contact surfaces in the engine during engine operation, said reduction being compared to using a lubricant containing the magnesium-containing detergent that does not contain an amount sufficient to provide 200-4000 ppm magnesium (ASTM D5185) to the lubricating oil composition.

[0152] Example

[0153] The present invention will now be described through the following embodiments, which are not intended to limit the scope of the claims of the present invention.

[0154] A series of oils were tested in a high-frequency reciprocating apparatus (HFRR supplied by PCS Instruments) to evaluate the boundary condition friction characteristics of the oils.

[0155] The device is equipped with a 6mm ball mounted on a 10mm plate. The testing procedure used is as follows:

[0156] The test has 6 temperature stages and can record the average friction at each temperature stage and the total average friction across all stages.

[0157] Four comparative oils (identified by the C- prefix) and five oils according to the invention (identified by the I- prefix) were tested. The composition of each oil is given in Table 1 below, along with the average HFRR friction across all test phases, and the low-temperature HFRR friction, which is the average of the 40°C and 60°C phases of the test.

[0158] As expected, the comparison of oils C-1, C-3, and I-3 shows that including high levels of molybdenum in lubricants containing magnesium or calcium detergents improves the average HFRR friction performance of the oils. The comparison of oils C-3 and I-3 also shows further improvement when the calcium detergent is replaced by a magnesium detergent. This further improvement resulting from replacing the calcium detergent with a magnesium detergent is unexpected.

[0159] The comparison between oil C-3 and oil C-4 and between oil I-1 and oil I-3 shows that, unexpectedly, the addition of boron with a significantly higher treatment rate also improves the tribological properties of HFRR in the presence of molybdenum with a high treatment rate.

[0160] A comparison of oils I-1 and I-2 shows that, in oils that are otherwise comparable, replacing the magnesium salicylate detergent with a magnesium sulfonate detergent significantly improves low-temperature friction performance, while maintaining the aforementioned performance improvements compared to calcium detergents. This improvement in low-temperature friction performance is unexpected.

[0161] Finally, the comparison between Oil I-4 and Oil I-5 shows that the best improvement in average HFRR friction can be obtained when using a combination of calcium and magnesium detergents. Similarly, the presence of magnesium sulfonate detergent in the calcium / magnesium detergent mixture further improves low-temperature friction performance.

[0162] Table 1

[0163] 1 The molybdenum compound is Infineum C9401, which is molybdenum didithiocarbamate available from Infineum UK Ltd.

[0164] 2 Calcium salicylate is Infineum C9329, a superalkaline detergent with 225 TBN and 8% by mass Ca, available from Infineum UK Ltd.

[0165] 3 Magnesium salicylate is Infineum C9012, a superalkaline detergent with 342 TBN and 7.4% Mg, available from Infineum UK Ltd.

[0166] 4Magnesium sulfonate is Infineum C9340, a superalkaline detergent with 400 TBN and 9.1% Mg, available from Infineum UK Ltd.

[0167] 5 The boronized dispersant is Infineum C9202, which is a boronized ashless polyisobutylene succinimide dispersant containing 2.3% by mass B, available from Infineum UK Ltd.

[0168] 6 Additional additives were provided by a detergent inhibitor package containing a non-boronized dispersant, zinc dialkyl dithiophosphate, and an antioxidant. The amount of each of these additives was the same in each oil tested.

Claims

1. A crankcase lubricating oil composition for four-wheeled or more-wheeled vehicles, comprising or prepared by mixing the following components: (A) The main amount of lubricating viscosity oil; (B) To provide the lubricating oil composition with an oil-soluble or oil-dispersible molybdenum-containing additive containing 700-1200 ppm of molybdenum atoms, (C) A detergent composition containing one or more magnesium sulfonate detergents, wherein the amount of magnesium atoms in the lubricating oil composition is 200-4000 ppm as measured according to ASTM D5185, and wherein the detergent composition further comprises calcium salicylate detergent, and (D) An oil-soluble or oil-dispersible boronizing dispersant compound present in the lubricating oil composition in an amount sufficient to provide 200-600 ppm boron atoms as measured according to ASTM D5185. The ratio of detergent atomic metal to atomic molybdenum in the lubricating oil composition is less than 3, and the borate dispersant compound contains borate polyolefin succinimide.

2. The lubricating oil composition of claim 1, wherein the detergent composition comprises one or more additional detergent additives selected from magnesium salicylate, calcium sulfonate, magnesium phenolate, calcium phenolate, mixed detergents containing two or more of these additional detergent additives and / or combinations thereof.

3. The lubricating oil composition of claim 2, wherein the detergent composition further comprises a calcium sulfonate detergent.

4. The lubricating oil composition according to claim 1, wherein the detergent composition comprises one or more magnesium sulfonate detergents and one or more calcium salicylate detergents.

5. The lubricating oil composition according to any one of claims 1-4, wherein the calcium-containing detergent is present in an amount sufficient to provide the lubricating oil composition with 500-4000 ppm, preferably 750-3000 ppm, more preferably 900-2000 ppm of atomic calcium as measured according to ASTM D5185.

6. The lubricating oil composition according to any one of claims 1-5, wherein the ratio of detergent atomic metal to atomic molybdenum in the lubricating oil composition is less than 2.

7. A method for lubricating a spark-ignition or compression-ignition internal combustion engine for a four-wheeled or more-wheeled vehicle, comprising lubricating the engine with a lubricating oil composition as defined in any one of the preceding claims.

8. The use of the crankcase lubricating oil composition of any one of claims 1-6 to reduce the low-temperature boundary friction measurement of spark-ignition or compression-ignition internal combustion engines of four-wheel or more vehicles, wherein the reduction is compared to an equivalent lubricant containing a magnesium-containing detergent that does not provide the lubricating oil composition with an amount sufficient to provide 200-4000 ppm of magnesium as measured according to ASTM D5185, wherein the low-temperature boundary friction measurement is measured using a high-frequency reciprocating device and is an average of the 40°C and 60°C phases of the test.

9. The use according to claim 8, wherein the oil-soluble or oil-dispersible molybdenum-containing additive provides 700-1000 ppm molybdenum atoms (ASTM D5185) to the lubricating oil composition.

10. The use according to claim 8 or 9, wherein the detergent composition further comprises one or more additional detergent additives selected from magnesium salicylate, magnesium phenolate, calcium phenolate and / or calcium sulfonate.

Images