Lubricating oil composition

Abstract

A low ash lubricating oil composition is described. The composition comprises a major amount of oil of lubricating viscosity, a detergent system, and a boron-containing additive in an amount providing at least 100 ppm of boron to the lubricating oil composition. The detergent system comprises one or more magnesium-containing detergents, and optionally one or more calcium-containing detergents. The lubricating oil composition is zinc and phosphorus free. The lubricating oil composition has a total sulfated ash content of 0.30 wt% to 0.80 wt%. The lubricating oil composition has a total base number of 4.0 to 9.5 mg KOH / g.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63 / 314,492, filed February 28, 2022, which is incorporated herein by reference in its entirety. [Background technology]

[0002] Phosphorus-containing antiwear additives are widely used as antiwear agents in lubricating oils to provide protection against wear and / or corrosion. One problem associated with these components is that phosphorus can accumulate in automotive catalytic converters, reducing the efficiency, effectiveness, and / or life of the converter unit. As a result, regulatory agencies and the automotive industry are pushing for a reduction in the phosphorus content of lubricating oils. Therefore, it is desirable to reduce the phosphorus content in lubricating oils while maintaining adequate protection against wear and / or corrosion. Summary of the Invention

[0003] In one embodiment, the present invention provides a low ash lubricating oil composition comprising a major amount of oil of lubricating viscosity; a detergent system comprising one or more magnesium-containing detergents, and optionally one or more calcium-containing detergents; and a boron-containing additive in an amount to provide the lubricating oil composition with at least 100 ppm of boron, wherein the lubricating oil composition is zinc and phosphorus-free, the lubricating oil composition has a total sulfated ash content of 0.30 wt% to 0.80 wt%, and the lubricating oil composition has a total base number of 4.0 to 9.5 mg KOH / g.

[0004] In another embodiment, the present invention provides a method for reducing corrosion in an engine, the method comprising providing a lubricating oil composition to an engine, the lubricating oil composition comprising: a major amount of oil of lubricating viscosity; a detergent system including one or more calcium-overbased detergents and one or more overbased magnesium-containing detergents; a zinc dithiophosphate in an amount to provide the lubricating oil composition with a phosphorus content of 0 to 300 ppm; a boron-containing additive in an amount to provide the lubricating oil composition with less than 300 ppm of boron; and a molybdenum compound in an amount to provide the lubricating oil composition with 50 to 500 ppm of molybdenum, wherein the lubricating oil composition has a calcium content of up to about 1300 ppm, based on the total weight of the lubricating oil composition, a total sulfated ash content of 0.40 wt% to 0.80 wt%, and a total base number of 4.0 to 9.0 mg KOH / g. DETAILED DESCRIPTION OF THE INVENTION

[0005] While the present disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof are described in detail herein. It should be understood, however, that the description of specific embodiments herein is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.

[0006] To facilitate understanding of the subject matter disclosed herein, several terms, abbreviations, or other shorthand notations used herein are defined below. Any term, abbreviation, or shorthand notation not defined will be understood to have its ordinary meaning as used by one of ordinary skill in the art contemporaneous with the filing of this application.

[0007] definition As used herein, the following terms have the following meanings unless otherwise specified: As used herein, the following words and expressions have the meanings ascribed to them if and when used.

[0008] By "major amount" is meant greater than 50% by weight of the composition.

[0009] "Minor amount" means, with respect to the additive being described and with respect to the total weight of all additives present in the composition, less than 50 wt. % of the composition, calculated and expressed as the active ingredient of the additive.

[0010] "Active ingredient" or "active agent" or "oil-free" refers to additive materials that are not diluents or solvents.

[0011] All percentages reported are weight percent on an active ingredient basis (ie, without regard to carrier or diluent oil) unless otherwise stated.

[0012] The abbreviation "ppm" means parts per million by weight based on the total weight of the lubricating oil composition.

[0013] High temperature high shear (HTHS) viscosity at 150°C was determined according to ASTM D4683.

[0014] 100℃(KV 100 ) was determined according to ASTM D445.

[0015] The term "metal" refers to an alkali metal, an alkaline earth metal, or a mixture thereof.

[0016] The terms oil-soluble or dispersible are used throughout this specification and claims. The terms "oil-soluble" or "dispersible" mean that a given amount required to impart a desired level of activity or performance can be incorporated by dissolving, dispersing, or suspending in an oil of lubricating viscosity. Typically, this means that at least 0.001 wt. % of the material can be incorporated into a lubricating oil composition. For further discussion of oil-solubility and dispersibility, particularly the term "stably dispersible," see U.S. Pat. No. 4,320,019, which is expressly incorporated herein by reference for relevant teachings in this regard.

[0017] As used herein, the term "sulfated ash" refers to the non-burnable residue resulting from detergent and metal additives in a lubricating oil. Sulfated ash may be determined using ASTM test D874.

[0018] As used herein, the term "total base number" or "TBN" refers to the amount of base equivalent to milligrams of KOH in one gram of sample. Thus, a higher TBN number reflects more alkalinity and, therefore, more alkalinity. TBN was determined using the ASTM D2896 test. TBN numbers are based on detergent concentrates.

[0019] The term "overbased" refers to metal salts, such as metal salts of sulfonic acid, salicylic acid, and phenolic acid, in which the amount of metal present exceeds the stoichiometric amount. Such salts can have conversion levels 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" or "neutral" salt). The expression "metal ratio," often abbreviated as MR, is used to designate the ratio of the total chemical equivalents of metal in an overbased salt to the chemical equivalents of metal in a neutral salt, according to known chemical reactivity and stoichiometry. In normal or neutral salts, the metal ratio is 1; in overbased salts, the MR is greater than 1. They are commonly referred to as overbased, superbased, or overbased salts and can be salts of organic sulfuric acid, salicylic acid, or phenols.

[0020] The boron, calcium, magnesium, molybdenum, phosphorus, sulfur, and / or zinc content was determined according to ASTM D5185.

[0021] Nitrogen content was determined according to ASTM D4629.

[0022] All ASTM standards referred to herein are the most recent editions as of the filing date of this application.

[0023] Unless otherwise specified, all percentages are by weight.

[0024] While the present disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof are described in detail herein. It should be understood, however, that the description of specific embodiments herein is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.

[0025] The description and illustrations of the embodiments set forth herein are intended to provide a general understanding of the structure of the various embodiments.

[0026] The present invention provides lubricating oil compositions formulated to provide adequate protection against wear and / or corrosion.

[0027] The lubricating oil composition comprises a major amount of oil of lubricating viscosity, a detergent system comprising one or more magnesium-containing detergents and optionally one or more calcium-containing detergents, and a boron-containing additive. The boron-containing additive is present in an amount providing the lubricating oil composition with at least 100 ppm of boron. The lubricating oil composition is substantially free (about 50 ppm or less) of zinc and phosphorus. The lubricating oil composition has a total sulfated ash content of 0.30 wt% to 0.80 wt%. The lubricating oil composition has a total base number of 4.0 to 9.5 mg KOH / g.

[0028] Oil of lubricating viscosity An oil of lubricating viscosity (often referred to as a "base stock" or "base oil") is the primary liquid component of a lubricating oil into which additives, and possibly other oils, are mixed to produce the finished lubricating oil (or lubricating oil composition). Base oils are useful for making concentrates and lubricating oil compositions therefrom, and may be selected from natural and synthetic lubricating oils, and combinations thereof.

[0029] Natural oils include animal and vegetable oils, liquid petroleum oils, and hydrorefined and solvent-treated mineral lubricating oils of the paraffinic, naphthenic, and mixed paraffinic-naphthenic types. Oils of lubricating viscosity derived from coal or shale are also useful as base oils.

[0030] Synthetic lubricating oils include hydrocarbon oils such as polymerized and copolymerized olefins (e.g., polybutylene, polypropylene, propylene-isobutylene copolymers, chlorinated polybutylene, poly(1-hexene), poly(1-octene), poly(1-decene); alkylbenzenes (e.g., dodecylbenzene, tetradecylbenzene, dinonylbenzene, di(2-ethylhexyl)benzene), polyphenols (e.g., biphenyls, terphenyls, alkylated polyphenols), alkylated diphenyl ethers and alkylated diphenyl sulfides, and their derivatives, analogs, and homologs. Polymerized olefins may also be derived from biological sources, such as hydrocarbon terpenes, such as myrcene, ocimene, and farnesene, which may also be copolymerized with other olefins and further isomerized if desired.

[0031] Another suitable class of synthetic lubricating oils includes the esters of dicarboxylic acids (e.g., malonic acid, alkylmalonic acid, alkenylmalonic acid, succinic acid, alkylsuccinic acid and alkenylsuccinic acid, maleic acid, fumaric acid, azelaic acid, suberic acid, sebacic acid, adipic acid, linoleic acid dimer, phthalic acid) with various alcohols (e.g., butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether, propylene glycol). Specific examples of such esters include dibutyl adipate, di(2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate, diicosyl sebacate, linoleic acid dimer 2-ethylhexyl diester, and the complex ester formed by reacting one mole of sebacic acid with two moles of tetraethylene glycol and two moles of 2-ethylhexanoic acid.

[0032] Esters useful as synthetic oils also include C5-C6 esters such as neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol, and tripentaerythritol. 12 and those made from monocarboxylic acids, polyols, and polyol ethers.

[0033] Esters from biological sources are also useful as synthetic oils.

[0034] Base oils can be derived from Fischer-Tropsch synthesized hydrocarbons. Fischer-Tropsch synthesized hydrocarbons are made from synthesis gas containing H2 and CO using a Fischer-Tropsch catalyst. Such hydrocarbons typically require further processing to be useful as base oils. For example, the hydrocarbons can be hydroisomerized, hydrocracked and hydroisomerized, degreased, or hydroisomerized and degreased using processes known to those skilled in the art.

[0035] Unrefined oils, refined oils, and re-refined oils can be used in the lubricating oil composition. Unrefined oils are those obtained directly from natural or synthetic sources without further purification treatment. For example, shale oil obtained directly from retorting operations, petroleum oil obtained directly from distillation, or ester oil obtained directly from an esterification process without further treatment are unrefined oils. Refined oils are similar to unrefined oils except that they have been further processed in one or more purification steps to improve one or more properties. Many such purification techniques, such as distillation, solvent extraction, acid or base extraction, filtration, and percolation, are known to those skilled in the art.

[0036] Re-refined oils are obtained by processes similar to those used to obtain refined oils applied to refined oils already in service. Such re-refined oils are also known as reclaimed or reprocessed oils and are often processed by techniques for the recognition of spent additives and oil breakdown products.

[0037] Thus, the base oils that can be used to make the lubricating oil compositions of the present invention can be selected from any of the base oils within Group IV as defined in the American Petroleum Institute (API) Base Oil Interchangeability Guidelines (API Publication 1509). Such base oil groups are summarized in Table 1 below: [Table 1]

[0038] Suitable base oils for use herein are any of the API Group II, Group III, Group IV, and Group V oils, and combinations thereof, preferably the varieties corresponding to Group III through Group V due to their excellent volatility, stability, viscosity, and cleanliness characteristics.

[0039] The oil of lubricating viscosity (also referred to as base oil) for use in the lubricating oil compositions of this disclosure is typically present in a major amount (e.g., greater than 50 wt.%, preferably greater than about 70 wt.%, more preferably about 80 to about 99.5 wt.%, and most preferably about 85 to about 98 wt.%, based on the total weight of the composition). As used herein, the expression "base oil" should be understood to mean a base stock or mixture of base stocks that are lubricating oil components produced by a single manufacturer to identical specifications (independent of source or location of manufacturer), which meet the same manufacturer's specifications and are identified by a unique chemical formula, product identification number, or both. Base oils for use herein may be any presently known or later-developed oil of lubricating viscosity, e.g., hydraulic oils, gear oils, transmission fluids, and the like, engine oils, marine cylinder oils, functional fluids, etc., used in formulating lubricating oil compositions for any and all such applications. In addition, the base oils for use herein may optionally contain viscosity index improvers, such as polymeric alkyl methacrylates, olefin copolymers such as ethylene-propylene copolymers, styrene-butadiene copolymers, and the like, and mixtures thereof.

[0040] As one skilled in the art will readily recognize, the viscosity of the base oil will depend on the application. Thus, the viscosity of the base oil for use herein will typically range from about 2 to about 2000 centistokes (cSt) at 100 degrees Celsius (°C). Generally, base oils used individually as engine oils will have a kinematic viscosity range of about 2 cSt to about 30 cSt at 100°C, preferably about 3 cSt to about 16 cSt, and most preferably about 4 cSt to about 12 cSt, and are selected or blended to produce a desired grade of engine oil (e.g., 0W, 0W-8, 0W-12, 0W-16, 0W-20, 0W-22, 0W-24, 0W-26, 0W-28, 0W-29, 0W-30, 0W-31, 0W-32, 0W-33, 0W-34, 0W-35, 0W-36, 0W-37, 0W-38, 0W-39, 0W-40, 0W-41, 0W-42, 0W-43, 0W-44, 0W-45, 0W-46, 0W-47, 0W-48, 0W-49, 0W-49, 0W-49, 0W-49, 0W-49, 0W-49, 0W-49, 0W-40, 0W-41, 0W-42, 0W-43, 0W-44, 0W-45, 0W-46, 0W-47, 0W-48, 0W-49, 0W-49, 0W-49, 0W-49, 0W-49, 0W-49, and the like).

[0041] In one embodiment, the sulfated ash level produced by the lubricating oil compositions of this disclosure is from about 0.40 to about 0.80 wt.%, as determined by ASTM D 874. In one embodiment, the sulfated ash level produced by the lubricating oil compositions of this disclosure is from about 0.40 to about 0.70 wt.%, as determined by ASTM D 874. In one embodiment, the sulfated ash level produced by the lubricating oil compositions of this disclosure is from about 0.40 to about 0.60 wt.%, as determined by ASTM D 874. In one embodiment, the sulfated ash level produced by the lubricating oil compositions of this disclosure is from about 0.50 to about 0.80 wt.%, as determined by ASTM D 874. In one embodiment, the sulfated ash level produced by the lubricating oil compositions of this disclosure is from about 0.60 to about 0.80 wt.%, as determined by ASTM D 874.

[0042] The lubricating oil composition of the present disclosure may have a total base number of 4.0 mgKOH / g to 9.0 mgKOH / g. In one embodiment, the total base number is 4.0 mgKOH / g to 8.5 mgKOH / g. In one embodiment, the total base number is 4.0 mgKOH / g to 8.0 mgKOH / g. In one embodiment, the total base number is 4.0 mgKOH / g to 7.5 mgKOH / g. In one embodiment, the total base number is 4.0 mgKOH / g to 7.0 mgKOH / g. In one embodiment, the total base number is 4.0 mgKOH / g to 6.5 mgKOH / g. In one embodiment, the total base number is 4.0 mgKOH / g to 6.0 mgKOH / g. In one embodiment, the total base number is 4.5 mgKOH / g to 9.0 mgKOH / g. In one embodiment, the total base number is 5.0 mgKOH / g to 9.0 mgKOH / g. In one embodiment, the total base number is 5.5 mgKOH / g to 9.0 mgKOH / g. In one embodiment, the total base number is 6.0 mgKOH / g to 9.0 mgKOH / g. In one embodiment, the total base number is 5.0 mgKOH / g to 8.0 mgKOH / g.

[0043] Detergents The lubricating oil compositions of the present invention comprise a detergent system comprising a mixture of detergent components including one or more magnesium-containing detergents and, optionally, one or more calcium-containing detergents. Suitable detergent components include magnesium-containing detergents and / or calcium-containing overbased detergents.

[0044] Examples of overbased detergents include overbased sulfonates and overbased salicylates.

[0045] The overbased detergent has a TBN of about 250 mg KOH / gram or more, or about 300 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, based on the detergent concentrate. In some embodiments, the detergent system includes an overbased phenolate detergent having a TBN of about 250 mg KOH / gram or more and / or a low overbased sulfonate detergent having a TBN of up to about 180 mg KOH / gram.

[0046] The magnesium-containing detergent(s) may be present in the lubricating oil composition at about 50 to about 1000 ppm, e.g., about 100 to about 900 ppm, about 150 ppm to about 850 ppm, about 200 ppm to about 800 ppm, about 250 ppm to about 750 ppm, about 300 ppm to about 700 ppm, about 350 ppm to about 650 ppm, about 400 ppm to about 600 ppm, about 50 ppm to about 95 0ppm, about 50ppm to about 900ppm, about 50ppm to about 850ppm, about 50ppm to about 800ppm, about 50ppm to about 750ppm, about 50ppm to about 700ppm, Approximately 50ppm to approximately 650ppm, approximately 50ppm to approximately 600ppm, approximately 50ppm to approximately 550ppm, approximately 50ppm to approximately 500ppm, approximately 100ppm to approximately 800ppm, approximately 100p pm ~ about 700ppm, about 100ppm - about 600ppm, about 100ppm - about 500ppm, about 150ppm - about 1000ppm, about 150ppm - about 900ppm, about 150 ppm~about 800ppm, about 150ppm~about 700ppm, about 150ppm~about 700ppm, about 200ppm~about 1000ppm, about 200ppm~about 900ppm, about 200 ppm to about 800 ppm, about 200 ppm to about 700 ppm, about 200 ppm to about 600 ppm, about 300 ppm to about 1000 ppm, about 300 ppm to about 900 ppm, about 300 ppm to about 800 ppm, about 300 ppm to about 800 ppm, about 300 ppm to about 700 ppm, and about 300 ppm to about 600 ppm of magnesium.

[0047] The optional calcium-containing detergent(s) are present in an amount to provide the lubricating oil composition with up to about 1300 ppm, e.g., up to about 1200 ppm, up to about 1100 ppm, up to about 1000 ppm, up to about 900 ppm, up to about 800 ppm, up to about 700 ppm, up to about 600 ppm, up to about 500 ppm, up to about 400 ppm, up to about 300 ppm, up to about 200 ppm, up to about 100 ppm, and up to about 50 ppm of calcium.

[0048] The ppm values ​​are based on the total weight of the lubricating oil composition.

[0049] Sulfonates can typically be prepared from sulfonic acids obtained by sulfonation of alkyl-substituted aromatic hydrocarbons, such as those obtained from petroleum fractionation, or by alkylation of aromatic hydrocarbons. Examples include those obtained by alkylating benzene, toluene, xylene, naphthalene, diphenyl, or their halogen derivatives. Alkylation can be carried out in the presence of an alkylating agent having from about 3 to more than 70 carbon atoms and a catalyst. Alkaryl sulfonates typically contain from about 9 to 80 or more carbon atoms (e.g., from about 16 to 60 carbon atoms) per alkyl-substituted aromatic moiety.

[0050] Salicylates can be prepared by reacting a basic metal compound with at least one carboxylic acid and removing water from the reaction product. Detergents made from salicylic acid are a class of detergents prepared from carboxylic acids. Useful salicylates include long-chain alkyl salicylates. One useful family of compositions has the following structure: [ka] (Wherein, R″ is C1 to C 30 (For example, C 13 ~C 30 ) alkyl group, n is an integer from 1 to 4, and M is an alkaline earth metal (e.g., Ca or Mg).

[0051] Hydrocarbyl-substituted salicylic acids can be prepared from phenols by the Kolbe reaction (see U.S. Pat. No. 3,595,791). Metal salts of hydrocarbyl-substituted salicylic acids can be prepared by metathesis of the metal salt in a polar solvent such as water or an alcohol.

[0052] Suitable phenates can be prepared by reacting an alkaline earth metal hydroxide or oxide (e.g., CaO, Ca(OH), MgO, or Mg(OH)) with an alkylphenol or sulfurized alkylphenol. Useful alkyl groups include linear or branched C1-C 30 (For example, C4~C 20 ) alkyl groups, or mixtures thereof. Examples of suitable phenols include isobutylphenol, 2-ethylhexylphenol, nonylphenol, and dodecylphenol. It should be noted that the starting alkylphenol may contain more than one alkyl substituent, each of which may be independently linear or branched. When a non-sulfurized alkylphenol is used, the sulfurized product may be obtained by methods known in the art. These methods include heating a mixture of an alkylphenol and a sulfurizing agent (such as elemental sulfur and sulfur halides such as sulfur dichloride), and then reacting the sulfurized phenol with an alkaline earth metal base.

[0053] Overbased sulfonate and / or salicylate detergents The lubricating oil composition comprises one or more overbased calcium sulfonate and / or calcium salicylate detergents having a total base number greater than 250 mg KOH / g, as measured by the method of ASTM D-2896, and present in an amount to provide the lubricating oil composition with 700 to 1300 ppm calcium. In some embodiments, the one or more overbased calcium sulfonate and / or calcium salicylate detergents having a total base number greater than 250 mg KOH / g, as measured by the method of ASTM D-2896, are present in an amount to provide the lubricating oil composition with 800 to 1300 ppm calcium, 800 to 1250 ppm calcium, or 850 to 1250 ppm calcium. In some embodiments, the one or more overbased calcium sulfonate and / or calcium salicylate detergents have a total base number greater than 250 mg KOH / g, as measured by the method of ASTM D-2896.

[0054] Magnesium-containing cleaner The one or more magnesium-containing detergents may be overbased magnesium-containing detergents having a total base number greater than 250 mg KOH / g as measured by the method of ASTM D-2896, and the one or more overbased magnesium-containing detergents may be selected from overbased magnesium sulfonate detergents, overbased magnesium phenate detergents, overbased magnesium salicylates, and mixtures thereof. Alternatively, the magnesium-containing detergent may include one or more of the magnesium-containing detergents described above, including low-based / neutral magnesium-containing detergents.

[0055] Preferred magnesium-containing detergents include magnesium sulfonate, magnesium phenate, and magnesium salicylate, especially magnesium sulfonate.

[0056] Overbased phenate detergent Optionally, the lubricating oil composition comprises an overbased phenate detergent having a total base number greater than 250 mg KOH / g. In one embodiment, the overbased phenate is calcium phenate. In one embodiment, the overbased calcium phenate is sulfurized calcium phenate.

[0057] Boron-containing additives The lubricating oil composition comprises about 100 ppm or more, e.g., about 120 ppm or more, about 150 ppm or more, about 175 ppm or more, about 200 ppm or more, or about 250 ppm or more of boron based on the weight of the lubricating oil composition.

[0058] The boron-containing additive can be any suitable oil-soluble or oil-dispersible compound. The boron-containing additive can be prepared by reacting a boron compound with an oil-soluble or oil-dispersible additive or compound. The boron compound can include boron oxide, boron oxide hydrate, boron trioxide, boron trifluoride, boron tribromide, boron trichloride, boric acid, boric acid, boric acid such as tetraboric acid and metaboric acid, boron hydride, boron amide, and various esters of boron acid. For example, the boron-containing additive can be one or more of the following: borated dispersant; borated dispersant viscosity index improver; alkali metal or mixed alkali metal or alkaline earth metal borate; borated overbased metal detergent; borated epoxide; boric acid ester; sulfurized boric acid ester; boric acid amide. Preferably, the boron-containing additive is one or more of a borated dispersant, a borate ester, or a borated overbased metal detergent. Optionally, if present, the borated overbased metal detergent is a borated overbased metal detergent having a TBN of at least 150, such as a borated overbased calcium detergent having a TBN of at least 150.

[0059] Examples of borated dispersants include borated ashless dispersants, such as borated polyalkenyl succinic anhydrides; borated non-nitrogen-containing derivatives of polyalkylene succinic anhydrides; borated basic nitrogen compounds selected from the group consisting of succinimides, carboxylic acid amides, hydrocarbyl monoamines, hydrocarbyl polyamines, Mannich bases, thiazoles (e.g., 2,5-dimercapto-1,3,4-thiadiazole, mercaptobenzothiazole, and derivatives thereof), triazoles (e.g., alkyltriazoles and benzotriazoles), copolymers containing carboxylic acid esters with one or more additional polar functional groups, including amines, amides, imines, imides, hydroxyls, carboxyls, etc. (e.g., products prepared by copolymerization of long-chain alkyl acrylates or methacrylates with monomers of the above functionalities); and the like, and combinations thereof. Preferred borated dispersants are succinimide derivatives of boron, such as borated polyisobutenyl succinimides.

[0060] An example of a borated ashless dispersant is a borated ashless hydrocarbyl succinimide dispersant prepared by reacting a hydrocarbyl succinic acid or anhydride with an amine. Preferred hydrocarbyl succinic acids or anhydrides are those in which the hydrocarbyl group is derived from a polymer of a C3 or C4 monoolefin, particularly polyisobutylene, and the polyisobutenyl group has a number average molecular weight (Mn) of 700 to 5,000, more preferably 900 to 2,500. Such dispersants generally have at least one, preferably 1 to 2, more preferably 1.1 to 1.8 succinic acid groups for each polyisobutenyl group. In one embodiment, the oil-soluble or oil-dispersible borated polyisobutylene succinimide dispersant is derived from a polyisobutylene group having a number average molecular weight of about 550 to about 5,000. In one embodiment, the oil-soluble or oil-dispersible borated polyisobutylene succinimide dispersant is derived from a polyisobutylene group having a number average molecular weight of from about 550 to about 4000. In one embodiment, the oil-soluble or oil-dispersible borated polyisobutylene succinimide dispersant is derived from a polyisobutylene group having a number average molecular weight of from about 550 to about 3000. In one embodiment, the oil-soluble or oil-dispersible borated polyisobutylene succinimide dispersant is derived from a polyisobutylene group having a number average molecular weight of from about 550 to about 2300. In one embodiment, the oil-soluble or oil-dispersible borated polyisobutylene succinimide dispersant is derived from a polyisobutylene group having a number average molecular weight of from about 950 to about 2300. In one embodiment, the oil-soluble or oil-dispersible borated polyisobutylene succinimide dispersant is derived from a polyisobutylene group having a number average molecular weight of from about 950 to about 1300. In one embodiment, the oil-soluble or oil-dispersible borated polyisobutylene succinimide dispersant is derived from a polyisobutylene group having a number average molecular weight of about 2300. In one embodiment, the oil-soluble or oil-dispersible borated polyisobutylene succinimide dispersant is derived from a polyisobutylene group having a number average molecular weight of about 1300. In one embodiment, the oil-soluble or oil-dispersible borated polyisobutylene succinimide dispersant is derived from a polyisobutylene group having a number average molecular weight of about 1000.

[0061] Preferred amines for reaction to form succinimides are polyamines having from 2 to 60 carbon atoms and from 2 to 12 nitrogen atoms per molecule, with polyalkylene amines of the formula: NH2(CH2) n -(NH(CH2) n ) m -NH2 (where n is 2 to 3 and m is 0 to 10.) Illustrative examples are ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, tetrapropylenepentamine, and pentaethylenehexamine, as well as commercially available mixtures of such polyamines. Amines containing other groups, such as hydroxy, alkoxy, amide, nitride, and imidazoline groups, can also be used and may be polyoxyalkylene polyamines. The amine is reacted with an alkenyl succinic acid or anhydride in a conventional molar ratio of about 1:1 to 10:1, preferably 1:1 to 3:1, and preferably about 1:1, of alkenyl succinic acid or anhydride to polyamine, typically by heating the reactants to 100°C to 250°C, preferably 125°C to 175°C, for 1 to 10 hours, preferably 2 to 6 hours.

[0062] Boronation of alkenyl succinimide dispersants is also described in U.S. Patent Nos. 3,087,936 and 3,254,025. The succinimide may be treated with a boron compound selected from the group consisting of boron, boron oxide, boron halides, boronic acids, and esters thereof, in an amount to provide an atomic ratio of boron of 0.1 to 10 relative to the respective atomic ratio of nitrogen in the dispersant.

[0063] The borated product generally contains 0.1 to 2.0 weight percent, preferably 0.2 to 0.8 weight percent, of boron based on the total weight of the borated dispersant. The boron is believed to exist as a dehydrated boric acid polymer bound in the imide metabolite salt. The boronization reaction is readily carried out by adding 1 to 3 weight percent (based on the weight of the dispersant) of the above boron compounds.

[0064] Examples of borated friction modifiers include, but are not limited to, borated fatty epoxides, borated alkoxylated fatty amines, borated glycerol esters, and the like, and mixtures thereof.

[0065] Hydrated particulate alkali metal borate is well known in the art and commercially available.The representative examples of hydrated particulate alkali metal borate and its preparation method are disclosed in, for example, U.S. Patent No. 3,313,727; U.S. Patent No. 3,819,521; U.S. Patent No. 3,853,772; U.S. Patent No. 3,907,601; U.S. Patent No. 3,997,454; U.S. Patent No. 4,089,790; U.S. Patent No. 6,737,387 and U.S. Patent No. 6,534,450, and the contents thereof are incorporated herein by reference. Hydrated alkali metal borates can be represented by the formula: MO.mBO.nHO, where M is an alkali metal of atomic number ranging from about 11 to about 19, e.g., sodium and potassium; m is a number from about 2.5 to about 4.5 (both whole numbers and fractions); and n is a number from about 1.0 to about 4.8. Hydrated sodium borate is preferred. The hydrated borate particles generally have an average particle size of less than about 1 micron.

[0066] Examples of borated epoxides include those obtained from the reaction product of one or more boron compounds with at least one epoxide. Suitable boron compounds include boron oxide, boron oxide hydrate, boron trioxide, boron trifluoride, boron tribromide, boron trichloride, boronic acid, boric acid, boronic acids such as tetraboric acid and metaboric acid, boron amides, and various esters of boronic acid. The epoxides are generally aliphatic epoxides having from about 8 to about 30 carbon atoms, preferably from about 10 to about 24 carbon atoms, and more preferably from about 12 to about 20 carbon atoms. Suitable aliphatic epoxides include dodecene oxide, hexadecene oxide, and the like, and mixtures thereof. Mixtures of epoxides, such as commercially available mixtures of epoxides having from about 14 to about 16 carbon atoms or from about 14 to about 18 carbon atoms, may also be used. Borated epoxides are generally known and are described, for example, in US Pat. No. 4,584,115.

[0067] Examples of borate esters include those obtained by reacting one or more of the boron compounds disclosed above with one or more alcohols having suitable lipophilic properties. Typically, the alcohol contains 6 to about 30 carbon atoms, preferably 8 to about 24 carbon atoms. Methods for making such borate esters are well known in the art. Representative examples of borate esters include those having the structure set forth in the following formula: [ka] wherein each R independently represents C1-C 12 is a straight or branched chain alkyl group of R 1 is hydrogen or C1-C 12 is a straight or branched chain alkyl group.

[0068] Examples of borated fatty amines include those obtained by reacting one or more of the boron compounds disclosed above with one or more fatty amines (e.g., amines having from about 14 to about 18 carbon atoms).

[0069] Examples of borated amides include those obtained from the reaction products of linear or branched, saturated or unsaturated, monovalent fatty acids having 8 to about 22 carbon atoms, urea, and polyalkylene polyamines with boric acid compounds, etc., and mixtures thereof.

[0070] Examples of borated sulfonates include borated alkaline earth metal sulfonates obtained by (a) reacting, in the presence of a hydrocarbon solvent, (i) at least one oil-soluble sulfonic acid or alkaline earth metal sulfonate, or a mixture thereof; (ii) at least one alkaline earth metal source; (iii) at least one boron source; and (iv) an overbased acid other than the boron source, in an amount of 0 to less than 10 mole percent relative to the boron source; and (b) heating the reaction product of (a) to a temperature higher than the distillation temperature of the hydrocarbon solvent to distill off the hydrocarbon solvent and water from the reaction. Suitable borated alkaline earth metal sulfonates include, for example, those disclosed in U.S. Patent Application Publication No. 20070123437, the contents of which are incorporated herein by reference. Borated salicylates can be produced in a similar manner.

[0071] Preferably, at least a portion, such as a majority, of the boron content of the lubricating oil composition is provided by boron-containing dispersant additives. In one embodiment of the present invention, 100 wt.% of the boron in the lubricating oil composition is provided by one or more boron-containing dispersant additives, based on the weight of the boron in the lubricating oil composition.

[0072] Alternatively or additionally, at least a portion of the boron content of the lubricating oil composition is provided by a borated detergent.

[0073] Additionally or alternatively, at least a portion of the boron content of the lubricating oil composition is provided by borated glycerol esters.

[0074] In one embodiment of the present invention, at least a portion, such as a majority, of the boron content of the lubricating oil composition is provided by boron-containing compounds that are not dispersants.

[0075] Optionally, 100 wt.% of the boron in the lubricating oil composition, based on the weight of boron in the lubricating oil composition, is provided by one or more non-dispersant boron-containing compounds, such as borated detergents and / or borate esters. Optionally, 20 wt.% to 100 wt.%, preferably 40 wt.% to 80 wt.%, for example 50 wt.% to 70 wt.%, of the boron in the lubricating oil composition, based on the weight of boron in the lubricating oil composition, is provided by one or more borated dispersant(s) and / or borated glycerol ester(s).

[0076] Organomolybdenum Compounds The lubricating oil composition comprises a molybdenum-containing compound in an amount of from about 50 to about 500 ppm, e.g., from about 50 to about 450 ppm, from about 50 to about 400 ppm, from about 50 to about 350, or from about 50 to about 300 ppm molybdenum, relative to the molybdenum content of the lubricating oil composition.

[0077] The lubricating oil compositions herein may also optionally contain one or more molybdenum-containing compounds. The oil-soluble molybdenum compounds may have the functional properties of antiwear agents, antioxidants, friction modifiers, or mixtures thereof. The oil-soluble molybdenum compounds may include molybdenum dithiocarbamates, amine salts of molybdenum compounds, molybdenum xanthates, molybdenum thioxanoates, molybdenum sulfides, molybdenum carboxylates, molybdenum alkoxides, trinuclear organo-molybdenum compounds, molybdenum esters, molybdenum amides, and / or mixtures thereof. Molybdenum sulfides include molybdenum disulfide. The 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 dithiocarbamates, molybdenum, amine salts of molybdenum compounds, and mixtures thereof. In one embodiment, the oil-soluble molybdenum compound may be molybdenum dithiocarbamate.

[0078] Molybdenum dithiocarbamate (MoDTP) is an organo-molybdenum compound represented by the following structure: [ka] (In the formula, R 1 , R 2 , R 3 , and R 4 are each independently a straight-chain or branched-chain alkyl group having 4 to 18 carbon atoms (for example, 8 to 13 carbon atoms).

[0079] Suitable examples of molybdenum compounds that can be used include Molyvan 822™, Molyvan™ A, Molyvan 2000™, and Molyvan 855™ from RT Vanderbilt Co., Ltd., and Sakura-Lube™ S-165, S-200, S-300, S-310G, S-525, S-600, S-700, and S-710, and mixtures thereof, available from Adeka Corporation. Suitable molybdenum components are described in U.S. Patent No. 5,650,381, U.S. Patent No. RE37,363E1, U.S. Patent No. RE38,929E1, and U.S. Patent No. RE40,595E1, which are incorporated herein by reference in their entireties.

[0080] Additionally, the molybdenum compound may be an acidic molybdenum compound, including molybdic acid, ammonium molybdate, sodium molybdate, potassium molybdate, other alkali metal molybdates, and other molybdenum salts (e.g., sodium hydrogen molybdate, MoOCl, MoOBr, MoOCl, molybdenum trioxide, or similar acidic molybdenum compounds). Alternatively, the molybdenum can be provided in the composition by molybdenum / sulfur complexes of basic nitrogen compounds, as described, for example, in U.S. Pat. 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 U.S. Patent Application Publication No. 2002 / 0038525, which are incorporated by reference in their entireties.

[0081] Another class of suitable organomolybdenum compounds has the formula MoS k L n Q zand mixtures thereof, wherein S represents sulfur, L represents independently selected ligands having organic groups with a sufficient number of carbon atoms to render the compound soluble or dispersible in oil, k is 4 to 7, Q is selected from the group of neutral electron donor compounds such as water, amines, alcohols, and ethers, and z ranges from 0 to 5, including non-stoichiometric values. There may be at least 21 carbon atoms, e.g., at least 25, at least 30, or at least 35 carbon atoms, among all of the ligand organic groups. Additional suitable molybdenum compounds are described in U.S. Pat. No. 6,723,685, the entire contents of which are incorporated herein by reference.

[0082] In one embodiment, the molybdenum amine is a molybdenum succinimide complex. Suitable molybdenum succinimide complexes are described, for example, in U.S. Patent No. 8,076,275. These complexes are prepared by a process comprising reacting an acidic molybdenum compound with a polyamine alkyl or alkenyl succinimide of the following structure or a mixture thereof: [ka] (Wherein R is C 24 ~C 350 (For example, C 70 ~C 128 ) alkyl or alkenyl group; R' is a straight or branched chain alkylene group having 2 to 3 carbon atoms; x is 1 to 11, and y is 1 to 10.

[0083] The molybdenum compound used to prepare the molybdenum succinimide complex is an acidic molybdenum compound or a salt of an acidic molybdenum compound. "Acidic" means that the molybdenum compound reacts with basic nitrogen compounds as measured by ASTM D664 or D2896. Typically, acidic molybdenum compounds are hexavalent. Representative examples of suitable molybdenum compounds include molybdenum trioxide, molybdic acid, ammonium molybdate, sodium molybdate, potassium molybdate, other alkali metal molybdates, and other molybdenum salts, such as hydrogen salts (e.g., sodium hydrogen molybdate), MoOCl4, MoO2Br2, and Mo2O3Cl6.

[0084] Succinimides that can be used to prepare complexes are disclosed in numerous publications and are known in the art. Certain basic types of succinimides and related materials encompassed by the term "succinimide" in the prior art are taught in U.S. Patents 3,172,892, 3,219,666, and 3,272,746. The term "succinimide" is understood in the art to encompass many of the amide, imide, and amidine species that may be formed. However, the predominant product is succinimide, and this term has generally been accepted to refer to the product of the reaction of alkyl- or alkenyl-substituted succinic acids or anhydrides with nitrogen-containing compounds. Preferred succinimides are those prepared by reacting polyisobutenyl succinic anhydrides of about 70 to 128 carbon atoms with polyalkylene polyamines selected from triethylenetetramine, tetraethylenepentamine, and mixtures thereof.

[0085] The molybdenum succinimide complex may be post-treated with a sulfur source at a suitable pressure and a temperature not exceeding 120°C to provide a sulfurized molybdenum succinimide complex. The sulfurization step may be carried out for a period of about 0.5 to 5 hours (e.g., 0.5 to 2 hours). Suitable sulfur sources include elemental sulfur, hydrogen sulfide, phosphorus pentasulfide, sulfur dioxide of the formula R2S, xwherein R is a hydrocarbyl (e.g., C1-C 10 alkyl), and x is at least 3), organic polysulfides of C1-C 10 Includes mercaptans, inorganic sulfides and polysulfides, thioacetamides, and thioureas.

[0086] Additional lubricant additives The lubricating oil compositions of the present invention may also contain other conventional additives that can impart or improve any desired properties of the lubricating oil composition in which these additives are dispersed or dissolved. Any additive known to those skilled in the art can be used in the lubricating oil compositions disclosed herein. Some suitable additives are described in Mortier et al., "Chemistry and Technology of Lubricants," 2nd Edition, London, Springer, (1996); and Leslie R. Rudnick, "Lubricant Additives: Chemistry and Applications," New York, Marcel Dekker (2003), both of which are incorporated herein by reference. For example, the lubricating oil compositions may contain antioxidants, rust inhibitors, anti-tarnish agents, demulsifiers, metal deactivators, friction modifiers, pour point depressants, anti-foam agents, co-solvents, corrosion inhibitors, ashless dispersants, multifunctional agents, dyes, extreme pressure agents, and the like, and mixtures thereof. A variety of additives are known and commercially available. These additives, or similar compounds thereof, can be used to prepare the lubricating oil compositions of this disclosure by conventional mixing procedures.

[0087] Dispersants keep in suspension oil-insoluble materials resulting from oxidation during engine operation, thus preventing sludge flocculation and precipitation or deposition on metal parts. Dispersants useful herein include nitrogen-containing ashless (metal-free) dispersants known to be effective in reducing deposit formation when used in gasoline and diesel engines.

[0088] Suitable dispersants include hydrocarbyl succinimides, hydrocarbyl succinamides, mixed esters / amides of hydrocarbyl-substituted succinic acids, hydroxyesters of hydrocarbyl-substituted succinic acids, and Mannich condensation products of hydrocarbyl-substituted phenols, formaldehyde, and polyamines. Condensation products of polyamines and hydrocarbyl-substituted phenyl acids are also suitable. Mixtures of these dispersants can also be used.

[0089] Basic nitrogen-containing ashless dispersants are well-known lubricating oil additives, and their preparation methods are widely described in the patent literature.Preferred dispersants are alkenyl succinimides and succinimides, where the alkenyl substituent is preferably a long chain of more than 40 carbon atoms.These materials are easily prepared by reacting a hydrocarbyl-substituted dicarboxylic acid material with a molecule containing an amine functional group.Examples of suitable amines are polyamines, such as polyalkylene polyamines, hydroxy-substituted polyamines, and polyoxyalkylene polyamines.

[0090] A particularly preferred ashless dispersant is polyisobutenyl succinimide formed from polyisobutenyl succinic anhydride and a polyalkylene polyamine, such as a polyethylene polyamine of the formula: NH2(CH2CH2NH) z H (wherein z is 1 to 11). The polyisobutenyl group is derived from polyisobutene and preferably has a number average molecular weight (M) in the range of 700 to 3000 daltons (e.g., 900 to 2500 daltons). n For example, polyisobutenyl succinimide has an M of 900 to 2500 daltons. n It may also be a bis-succinimide derived from a polyisobutenyl group having the formula:

[0091] As is known in the art, dispersants can be post-treated (for example, with boronating agents, ethylene carbonate, or cyclic carbonates).

[0092] Nitrogen-containing ashless (metal-free) dispersants are basic and contribute to the TBN of the lubricating oil composition to which they are added without introducing additional sulfated ash.

[0093] The dispersant may be present at 0.1 to 10 wt.% (eg, 2 to 5 wt.%) of the lubricating oil composition.

[0094] The lubricating oil compositions of the present disclosure may contain one or more antioxidants capable of reducing or preventing oxidation of the base oil. Any antioxidant known to those skilled in the art may be used in the lubricating oil compositions. Non-limiting examples of suitable antioxidants include amine-based antioxidants (e.g., alkyldiphenylamines, such as bis-nonylated diphenylamine, bis-octylated diphenylamine, and octylated / butylated diphenylamine, phenyl-α-naphthylamine, alkyl- or aralkyl-substituted phenyl-α-naphthylamine, alkylated p-phenylenediamine, tetramethyl-diaminodiphenylamine, etc.), phenol-based antioxidants (e.g., 2-tert-butylphenol, 4-methyl-2,6-di ... butylphenol, 2,4,6-tri-tert-butylphenol, 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butylphenol, 4,4'-methylenebis-(2,6-di-tert-butylphenol), 4,4'-thiobis(6-di-tert-butyl-o-cresol), etc.), sulfur-based antioxidants (e.g., dilauryl-3,3'-thiodipropionate, sulfurized phenol-based antioxidants, etc.), phosphorus-based antioxidants (e.g., phosphites, etc.), and combinations thereof. The amount of antioxidant can vary from about 0.01 wt.% to about 10 wt.%, from about 0.05 wt.% to about 5 wt.%, or from about 0.1 wt.% to about 3 wt.%, based on the total weight of the lubricating oil composition.

[0095] The lubricating oil composition of the present disclosure may contain a friction modifier that can reduce friction between moving parts. Any friction modifier known to those skilled in the art may be used in the lubricating oil composition. Non-limiting examples of suitable friction modifiers include aliphatic carboxylic acids; derivatives of aliphatic carboxylic acids (e.g., alcohols, esters, borated esters, amides, and metal salts); mono-, di-, or tri-alkyl-substituted phosphoric or phosphonic acids; derivatives of mono-, di-, or tri-alkyl-substituted phosphoric or phosphonic acids (e.g., esters, amides, and metal salts); mono-, di-, or tri-alkyl-substituted amines; mono- or di-alkyl-substituted amides, and combinations thereof. In some embodiments, examples of friction modifiers include alkoxylated fatty amines, borated fatty epoxides, fatty epoxides, fatty amines, borated alkoxylated fatty amines, metal salts of fatty acids, fatty acid amides, glycerol esters, borated glycerol esters, and fatty imidazolines disclosed in U.S. Pat. No. 6,372,696, the contents of which are incorporated herein by reference, C4-C 75 , or C6~C 24 , or C6~C 20 and a nitrogen-containing compound selected from the group consisting of ammonia, alkanolamines, and the like, and mixtures thereof. The amount of friction modifier can vary from about 0.01 wt.% to about 10 wt.%, from about 0.05 wt.% to about 5 wt.%, or from about 0.1 wt.% to about 3 wt.%, based on the total weight of the lubricating oil composition.

[0096] The lubricating oil compositions of the present disclosure may contain one or more anti-foaming agents or defoaming inhibitors capable of dissipating air bubbles in the oil. Any anti-foaming agent or defoaming agent known to those skilled in the art may be used in the lubricating oil compositions. Non-limiting examples of suitable anti-foaming agents or defoaming agents include silicone oils or polydimethylsiloxanes, fluorosilicones, alkoxylated fatty acids, polyethers (e.g., polyethylene glycols), branched polyvinyl ethers, alkyl acrylate polymers, alkyl methacrylate polymers, polyalkoxyamines, and combinations thereof. In some embodiments, the anti-foaming agent or defoaming agent comprises glycerol monostearate, polyglycol palmitate, trialkyl monothiophosphate, esters of sulfonated ricinoleic acid, benzoylacetone, methyl salicylate, glycerol monooleate, or glycerol dioleate. The amount of anti-foam agent or anti-foaming agent can vary from about 0.001 wt.% to about 5 wt.%, from about 0.05 wt.% to about 3 wt.%, or from about 0.1 wt.% to about 1 wt.%, based on the total weight of the lubricating oil composition.

[0097] The lubricating oil compositions of this disclosure may contain one or more pour point depressants capable of lowering the pour point of the lubricating oil composition. Any pour point depressant known to those skilled in the art may be used in the lubricating oil composition. Non-limiting examples of suitable pour point depressants include polymethacrylic acid, alkyl acrylate polymers, alkyl methacrylate polymers, di(tetra-paraffin phenol) phthalate, condensates of tetra-paraffin phenol, condensates of chlorinated paraffins with naphthalene, and combinations thereof. In some embodiments, the pour point depressant includes ethylene-vinyl acetate copolymers, condensates of chlorinated paraffins and phenols, polyalkylstyrenes, and the like. The amount of pour point depressant may vary from about 0.01 wt.% to about 10 wt.%, from about 0.05 wt.% to about 5 wt.%, or from about 0.1 wt.% to about 3 wt.%, based on the total weight of the lubricating oil composition.

[0098] In one embodiment, the lubricating oil composition of the present disclosure does not contain one or more demulsifiers. In another embodiment, the lubricating oil composition of the present disclosure may contain one or more demulsifiers capable of promoting oil-water separation in lubricating oil compositions exposed to water or steam. Any demulsifier known to those skilled in the art may be used in the lubricating oil composition. Non-limiting examples of suitable demulsifiers include anionic surfactants (e.g., alkyl naphthalene sulfonates, alkyl benzene sulfonates, etc.), nonionic alkoxylated alkylphenol resins, alkylene oxide polymers (e.g., polyethylene oxide, polypropylene oxide, block copolymers of ethylene oxide and propylene oxide, etc.), esters of oil-soluble acids, polyoxyethylene sorbitan esters, and combinations thereof. The amount of demulsifier may vary from about 0.01 wt.% to about 10 wt.%, from about 0.05 wt.% to about 5 wt.%, or from about 0.1 wt.% to about 3 wt.%, based on the total weight of the lubricating oil composition.

[0099] The lubricating oil compositions of the present disclosure may contain one or more corrosion inhibitors capable of reducing corrosion. Any corrosion inhibitor known to those skilled in the art may be used in the lubricating oil compositions. Non-limiting examples of suitable corrosion inhibitors include half esters or amides of dodecyl succinic acid, alkyl imidazolines, sarcosines, and combinations thereof. The amount of corrosion inhibitor may vary from about 0.01 wt.% to about 5 wt.%, from about 0.05 wt.% to about 3 wt.%, or from about 0.1 wt.% to about 1 wt.%, based on the total weight of the lubricating oil composition.

[0100] The lubricating oil compositions of the present disclosure may optionally contain one or more extreme pressure (EP) agents capable of preventing seizure of sliding metal surfaces under extreme pressure conditions. Any extreme pressure agent known to those skilled in the art may be used in the lubricating oil compositions. In general, extreme pressure agents are compounds capable of chemically bonding with metals to form a surface film that prevents welding of asperities on opposing metal surfaces under high loads. Non-limiting examples of suitable extreme pressure agents include sulfurized animal or vegetable fats or oils, sulfurized animal or vegetable fatty acid esters, fully or partially esterified esters of trivalent or pentavalent acids of phosphorus, sulfurized olefins, dihydrocarbyl polysulfides, sulfurized Diels-Alder adducts, sulfurized dicyclopentadiene, sulfurized or co-sulfurized mixtures of fatty acid esters and monounsaturated olefins, co-sulfurized blends of fatty acids, fatty acid esters and alpha-olefins, functionally substituted dihydrocarbyl polysulfides, thiaaldehydes, thiaketones, epithio compounds, sulfur-containing acetal derivatives, co-sulfurized blends of terpenes and acyclic olefins, polysulfide olefin products, amine salts of phosphate esters or thiophosphate esters, and combinations thereof. The amount of extreme pressure agent can vary from about 0.01 wt.% to about 5 wt.%, from about 0.05 wt.% to about 3 wt.%, or from about 0.1 wt.% to about 1 wt.%, based on the total weight of the lubricating oil composition.

[0101] The lubricating oil composition of the present disclosure may contain a rust inhibitor capable of inhibiting corrosion of ferrous metal surfaces. Any rust inhibitor known to those skilled in the art may be used in the lubricating oil composition. Non-limiting examples of suitable rust inhibitors include nonionic polyoxyalkylene agents such as polyoxyethylene lauryl ether, polyoxyethylene higher alcohol ethers, polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene octylstearyl ether, polyoxyethylene oleyl ether, polyoxyethylene sorbitol monostearate, polyoxyethylene sorbitol monooleate ester, and monooleate polyethylene glycol; stearic acid and other fatty acids; dicarboxylic acids; metal soaps; fatty acid amine salts; metal salts of heavy sulfonic acids; partial carboxylic acid esters of polyhydric alcohols; (short-chain) alkenyl succinic acids; their partial esters and nitrogen-containing derivatives; synthetic alkaryl sulfonates, such as metal dinonylnaphthalene sulfonates; and the like, as well as mixtures thereof. The amount of rust inhibitor can vary from about 0.01 wt.% to about 10 wt.%, from about 0.05 wt.% to about 5 wt.%, or from about 0.1 wt.% to about 3 wt.%, based on the total weight of the lubricating oil composition.

[0102] The lubricating oil compositions of the present disclosure may contain one or more viscosity index improvers. Some non-limiting examples of suitable viscosity index improvers include, but are not limited to, olefin copolymers such as ethylene-propylene copolymers, styrene-isoprene copolymers, hydrated styrene-isoprene copolymers, polybutene, polyisobutylene, polymethacrylate, vinylpyrrolidone, and methacrylate copolymers, as well as dispersant-type viscosity index improvers. These viscosity modifiers can optionally be grafted with a grafting material, such as maleic anhydride, and the grafted material can be reacted with, for example, an amine, an amide, a nitrogen-containing heterocyclic compound, or an alcohol to form a multifunctional viscosity modifier (dispersant-type viscosity modifier). Other examples of viscosity modifiers include star polymers (e.g., star polymers containing isoprene / styrene / isoprene triblock). Further examples of viscosity modifiers include polyalkyl(meth)acrylates with low Brookfield viscosity and high shear stability, functionalized polyalkyl(meth)acrylates with high Brookfield viscosity and high shear stability dispersant properties, polyisobutylenes with weight average molecular weights ranging from 700 to 2,500 daltons, and mixtures thereof. The amount of viscosity index improver can vary from about 0.01 wt.% to about 25 wt.%, from about 0.05 wt.% to about 20 wt.%, or from about 0.3 wt.% to about 15 wt.%, based on the total weight of the lubricating oil composition.

[0103] The lubricating oil compositions of the present disclosure may contain one or more metal deactivators. Non-limiting examples of suitable metal deactivators include disalicylidene propylene diamine, triazole derivatives, thiadiazole derivatives, and mercaptobenzimidazole.

[0104] In the preparation of lubricating oil formulations, it is common practice to introduce additives in the form of concentrates of active ingredient at 10 to 80 wt. % in a hydrocarbon oil (e.g., mineral lubricating oil) or other suitable solvent.

[0105] Typically, these concentrates can be diluted with 3 to 100 (e.g., 5 to 40) parts by weight of lubricating oil per part by weight of additive package to form a finished lubricant (e.g., crankcase motor oil). Naturally, the purpose of the concentrate is to make handling of the various materials less difficult and awkward and to facilitate dissolution or dispersion in the final mixture.

[0106] Each of the foregoing additives, when used, is used in a functionally effective amount to impart the desired properties to the lubricant. Thus, for example, if an additive is a friction modifier, a functionally effective amount of the friction modifier would be an amount sufficient to impart the desired friction modifying properties to the lubricant.

[0107] Generally, the concentration of each of the additives in the lubricating oil composition, if used, may range from about 0.001 wt.% to about 20 wt.%, from about 0.01 wt.% to about 15 wt.%, or from about 0.1 wt.% to about 10 wt.%, from about 0.005 wt.% to about 5 wt.%, or from about 0.1 wt.% to about 2.5 wt.%, based on the total weight of the lubricating oil composition. Furthermore, the total amount of additives in the lubricating oil composition may range from about 0.001 wt.% to about 20 wt.%, from about 0.01 wt.% to about 10 wt.%, or from about 0.1 wt.% to about 5 wt.%, based on the total weight of the lubricating oil composition.

[0108] The following examples are provided to illustrate embodiments of the present disclosure and are not intended to limit the disclosure to the specific embodiments described. All parts and percentages are by weight unless otherwise indicated. All numerical values ​​are approximate. When numerical ranges are given, it should be understood that embodiments outside the stated ranges may still fall within the scope of the present disclosure. The specific details provided in each example should not be construed as necessary features of the present disclosure.

[0109] It will be understood that various modifications can be made to the embodiments disclosed herein. Therefore, the above description should not be construed as limiting, but merely as exemplifications of preferred embodiments. For example, the above-described functions implemented as the best mode for carrying out the disclosure are for illustrative purposes only. Those skilled in the art can implement other configurations and methods without departing from the scope and spirit of the present disclosure. Moreover, those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto. [Example]

[0110] The following examples are offered for illustrative purposes only and are not intended to limit the scope of the present disclosure in any way. Lubricant examples were prepared by blending a major amount of a Group III base oil of lubricating viscosity with the following additive combinations to provide a finished oil having a viscosity grade of 0W-16: Mixtures of borated and ethylene carbonate post-treated succinimide dispersants; primary alkyl ZnDTP, secondary alkyl ZnDTP, or both; borated organic friction modifiers; molybdenum succinimide compounds; diphenylamine antioxidants; one or more of an overbased calcium sulfonate detergent (TBN=410 mg KOH / g, Ca content=15.5 wt%), an overbased calcium phenate detergent (TBN=260 mg KOH / g, Ca content=9.6 wt%), an overbased calcium salicylate detergent (TBN=350 mg KOH / g, Ca content=12.5 wt%), and an overbased magnesium sulfonate detergent (TBN=400 mg KOH / g, Mg content=9.5 wt%); Small amounts of silicone antifoam agents, pour point depressants, and olefin copolymer type viscosity modifiers.

[0111] Ball Rust Test (BRT) - ASTM D6557 The Ball Rust Test (BRT) was performed using ASTM-D-6557. The BRT evaluates the anti-corrosion ability of a fluid lubricant. Ball bearings were immersed in oil according to ASTM D6557. Air saturated with acidic contaminants was bubbled through the oil for 18 hours at 49°C. After the 18-hour reaction period, the balls were removed from the test oil. The extent of ball corrosion was quantified as reflected light using a light reflection technique. The reflected light is reported as average gray value (AGV).

[0112] A new, uncorroded ball has an AGV of approximately 140. A completely corroded ball typically has an AGV of less than 20. A lubricant composition that results in an AGV of at least 100 passes the BRT. A lubricant composition that results in an AGV of less than 100 fails the BRT. The BRT results are summarized in Tables 2-4.

[0113] Table 2 shows that the presence of ZnDTP adversely affects BRT performance. In particular, Comparative Examples 1-5, which contained various levels and types of ZnDTP, all failed the BRT. [Table 2] [Table 3-1] [Table 3-2] [Table 4]

Claims

1. 1. A low ash lubricating oil composition comprising: a major amount of oil of lubricating viscosity; a detergent system comprising one or more magnesium-containing detergents, and optionally one or more calcium-containing detergents; a boron-containing additive in an amount providing at least 100 ppm of boron to said lubricating oil composition; the lubricating oil composition is free of zinc and phosphorus, the lubricating oil composition has a total sulfated ash content of 0.30 wt % to 0.80 wt %, and the lubricating oil composition has a total base number of 4.0 to 9.5 mg KOH / g.

2. 10. The lubricating oil composition of claim 1, wherein the composition contains at least 20 mmol / kg of calcium and / or magnesium detergent.

3. 2. The lubricating oil composition of claim 1, wherein the one or more overbased detergents individually have a total base number greater than 250 mg KOH / g.

4. 2. The lubricating oil composition of claim 1, wherein the detergent system provides up to 1300 ppm of calcium to the lubricating oil composition.

5. 2. The lubricating oil composition of claim 1, wherein the one or more magnesium-containing detergents are present in an amount to provide 50 to 1000 ppm of magnesium to the lubricating oil composition.

6. 10. The lubricating oil composition of claim 1, further comprising an antioxidant, an antifoam agent, a viscosity modifier, a pour point depressant, a dispersant, an extreme pressure agent, or a metal deactivator.

7. 2. The lubricating oil composition of claim 1, wherein the oil of lubricating viscosity is a Group III base oil.

8. 2. The lubricating oil composition of claim 1, wherein the magnesium-containing detergent is a sulfonate or a salicylate.

9. 2. The lubricating oil composition of claim 1, wherein the calcium-containing detergent is a sulfonate or a salicylate.

10. 1. A method for reducing corrosion in an engine, the method comprising: providing to the engine a lubricating oil composition comprising: a major amount of oil of lubricating viscosity; a detergent system comprising one or more calcium-overbased detergents and one or more magnesium-overbased detergents; a zinc dithiophosphate in an amount providing the lubricating oil composition with a phosphorus content of 0 to 300 ppm; a boron-containing additive in an amount providing less than 300 ppm of boron to the lubricating oil composition; a molybdenum compound in an amount to provide 50 to 500 ppm of molybdenum to the lubricating oil composition; the lubricating oil composition having a calcium content of up to about 1300 ppm based on the total weight of the lubricating oil composition; a total sulfated ash content of the lubricating oil composition of 0.40 wt % to 0.80 wt %; and a total base number of the lubricating oil composition of 4.0 to 9.0 mg KOH / g. The method.

11. 11. The method of claim 10, wherein the lubricating oil composition contains at least 20 mmol / kg of calcium and / or magnesium detergent.

12. 11. The method of claim 10, wherein the one or more overbased detergents individually have a total base number greater than 250 mg KOH / g.

13. 11. The method of claim 10, wherein the detergent system provides up to 1300 ppm of calcium to the lubricating oil composition.

14. The method of claim 10, wherein the one or more magnesium-containing detergents are present in an amount to provide 50 to 1000 ppm of magnesium in the lubricating oil composition.

15. 11. The method of claim 10, wherein the lubricating oil composition further comprises an antioxidant, an antifoam agent, a viscosity modifier, a pour point depressant, a dispersant, an extreme pressure agent, or a metal deactivator.

16. 11. The lubricating oil composition of claim 10, wherein the oil of lubricating viscosity is a Group III base oil.

17. 11. The method of claim 10, wherein the magnesium-containing detergent is a sulfonate or a salicylate.

18. 11. The method of claim 10, wherein the calcium-containing detergent is a sulfonate or a salicylate.

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