Lubricating oil composition

Abstract

To provide a lubricating oil composition that is effective for soot dispersibility and advantageously improves compatibility of fluorocarbon elastomer seal.SOLUTION: A lubricating oil composition comprises: (a) a major amount of an oil of lubricating viscosity having a kinematic viscosity at 100°C in a range of about 2 to about 50 mm2 / s; (b) a hydrocarbyl succinimide dispersant; (c) a borated hydrocarbyl succinimide dispersant; and (d) a hydrocarbyl succinimide post-treated with a post-treating agent selected from the group consisting of organic carbonate, epoxide, lactone, hydroxyaliphatic carboxylic acid, and combinations thereof.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The disclosed technology relates to lubricants for internal combustion engines, particularly compression ignition engines. [Background technology]

[0002] Lubricating oil compositions used to lubricate internal combustion engines and transmissions contain a major amount of a base oil of lubricating viscosity, or a mixture of such oils, and one or more lubricating oil additives to improve the performance characteristics of the oil. For example, lubricating oil additives are used to improve detergency, reduce engine wear, provide thermal and oxidative stability, reduce oil consumption, inhibit corrosion, act as dispersants, and reduce friction losses. Some additives provide multiple benefits, such as dispersant-viscosity modifiers.

[0003] Among the additives are dispersants, which, as the name suggests, provide engine cleanliness and are used to keep in suspension, for example, carbonate, carboxylate, carbonyl, soot, etc. The most widely used dispersants today are reaction products of succinic anhydride (PIBSA) substituted in the alpha position with alkyl chains of the polyisobutylene type with polyalkyleneamines, optionally post-treated with boron derivatives, ethylene carbonate, or other post-treatment reagents known in the specialist literature.

[0004] Among the polyamines used, polyalkyleneamines such as diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), pentaethylenehexamine (PEHA) and the heavier polyalkyleneamines (HPA) are preferred.

[0005] These polyalkyleneamines react with polyisobutylene-type alkyl-substituted succinic anhydrides (PIBSA) to produce monosuccinimides, bissuccinimides, or mixtures of monosuccinimides and bissuccinimides, depending on the molar ratio of these two reagents.

[0006] The reaction product, which may be post-treated if necessary, generally has a non-zero basic nitrogen content of about 5 to 50, measured by total base number or TBN, expressed as mg of KOH per gram of sample, and is therefore capable of protecting metal parts of an engine in use from corrosion by acidic components resulting from oxidation of the lubricating oil or fuel, while at the same time keeping the oxidation products dispersed in the lubricating oil and preventing their aggregation and deposition on the metal parts.

[0007] Monosuccinimide or bissuccinimide type dispersants are more effective if their relative basic nitrogen content is high, i.e., as long as the number of nitrogen atoms in the polyamine is greater than the number of succinic anhydride groups substituted by polyisobutenyl groups.

[0008] However, the higher basic nitrogen content of these dispersants makes them more susceptible to attack of the fluorocarbon elastomer seals used in modern engines, as the basic nitrogen tends to react with the acidic hydrogen atoms of fluorocarbon elastomer type seals, which attack results in the formation of cracks in the elastomer surface and the loss of other physical properties desired for this type of material.

[0009] It would therefore be desirable to develop lubricating oil compositions containing dispersants that are effective in dispersing soot while exhibiting improved fluorocarbon elastomer seal compatibility. Summary of the Invention

[0010] According to one exemplary embodiment,

[0011] (a) The main amount of about 2 to about 50 mm at 100°C 2 Oils of lubricating viscosity with kinematic viscosities in the range of 1 / s;

[0012] (b) hydrocarbyl succinimide dispersants;

[0013] (c) borated hydrocarbyl succinimide dispersants; and

[0014] (d) hydrocarbyl succinimides post-treated with a post-treating agent selected from the group consisting of organic carbonates, epoxides, lactones, hydroxyaliphatic carboxylic acids, and combinations thereof. A lubricating oil composition comprising:

[0015] According to a second exemplary embodiment, (a) a major amount of about 2 to about 50 mm at 100° C. 2 The present invention provides a method for producing a lubricating oil composition comprising: (a) an oil of lubricating viscosity having a kinematic viscosity in the range of 1 / 2 s / sec; (b) a hydrocarbyl succinimide dispersant; (c) a boronated hydrocarbyl succinimide dispersant; and (d) a hydrocarbyl succinimide that has been post-treated with a post-treating agent selected from the group consisting of organic carbonates, epoxides, lactones, hydroxyaliphatic carboxylic acids, and combinations thereof.

[0016] According to a third exemplary embodiment, there is provided a method for maintaining or improving compatibility of a lubricating oil composition with one or more fluorocarbon elastomer seals in an internal combustion engine comprising the steps of: (a) providing a major amount of fluorocarbon elastomer seals having a viscosity of from about 2 to about 50 mm at 100° C.; 2 The present invention provides a method for producing a lubricating oil composition comprising: (a) an oil of lubricating viscosity having a kinematic viscosity in the range of 1 / 2 s / sec; (b) a hydrocarbyl succinimide dispersant; (c) a boronated hydrocarbyl succinimide dispersant; and (d) a hydrocarbyl succinimide that has been post-treated with a post-treating agent selected from the group consisting of organic carbonates, epoxides, lactones, hydroxyaliphatic carboxylic acids, and combinations thereof.

[0017] The lubricating oil compositions of the present disclosure are also effective in soot dispersancy while advantageously improving the compatibility of fluorocarbon elastomer seals. The following [1] to

[20] are all embodiments of the present invention. [1] (a) The main amount of about 2 to about 50 mm at 100°C2 Oils of lubricating viscosity with kinematic viscosities in the range of 1 / s; (b) hydrocarbyl succinimide dispersants; (c) a boronated hydrocarbyl succinimide dispersant; and (d) hydrocarbyl succinimides post-treated with a post-treating agent selected from the group consisting of organic carbonates, epoxides, lactones, hydroxyaliphatic carboxylic acids, and combinations thereof. A lubricating oil composition comprising: [2] 1. The lubricating oil composition of claim 1, wherein the major amount of oil of lubricating viscosity is greater than 50 wt %, based on the total weight of the lubricating oil composition. [3] 1. The lubricating oil composition according to claim 1, wherein the hydrocarbyl group of the hydrocarbyl succinimide dispersant contains from about 12 to about 350 carbon atoms. [4] The lubricating oil composition according to [1], wherein the hydrocarbyl succinimide dispersant is a polyalkenyl succinimide. [5] The lubricating oil composition according to [4], wherein the polyalkenyl succinimide is polyisobutenyl bissuccinimide. [6] The lubricating oil composition according to [1], wherein the polyisobutenyl bissuccinimide is derived from a polyisobutylene group having a number average molecular weight of about 700 to about 2,500. [7] 1. The lubricating oil composition according to claim 1, wherein the boronated hydrocarbyl succinimide dispersant is a boronated polyalkenyl succinimide. [8] The lubricating oil composition according to [7], wherein the boronated polyalkenyl succinimide is a boronated polyisobutenyl bissuccinimide. [9] The lubricating oil composition according to [1], wherein the boronated polyisobutenyl bissuccinimide is derived from a polyisobutylene group having a number average molecular weight of about 700 to about 2,500.

[10] The lubricating oil composition according to [1], wherein the hydrocarbyl succinimide (d) is post-treated with an organic carbonate.

[11] The lubricating oil composition according to

[10] , wherein the organic carbonate is ethylene carbonate.

[12] about 0.5 wt % to about 12 wt % of a hydrocarbyl succinimide dispersant, based on the total weight of the lubricating oil composition; about 0.5 wt. % to about 12 wt. % of a boronated hydrocarbyl succinimide dispersant, based on the total weight of the lubricating oil composition; and about 0.5 wt. % to about 12 wt. % of a hydrocarbyl succinimide post-treated with a post-treating agent selected from the group consisting of organic carbonates, epoxides, lactones, and hydroxyaliphatic carboxylic acids, based on the total weight of the lubricating oil composition. The lubricating oil composition according to [1],

[13] 1. The lubricating oil composition of claim 1, wherein the mixture of the hydrocarbyl succinimide dispersant; the boronated hydrocarbyl succinimide dispersant; and the hydrocarbyl succinimide post-treated with a post-treating agent selected from the group consisting of organic carbonates, epoxides, lactones, hydroxyaliphatic carboxylic acids, and combinations thereof provides the lubricating oil composition with a total base number (TBN) of about 0.5 to about 5.

[14] The lubricating oil composition according to [1], further comprising at least one additive selected from antioxidants, metal detergents, rust inhibitors, dehazing agents, demulsifiers, metal deactivators, friction modifiers, pour point depressants, antifoam agents, cosolvents, corrosion inhibitors, multifunctional agents, dyes, extreme pressure agents, and mixtures thereof.

[15] (a) The main amount of about 2 to about 50 mm at 100°C 2 (b) an oil of lubricating viscosity having a kinematic viscosity in the range of 1 / 2 s / sec; (b) a hydrocarbyl succinimide dispersant; (c) a boronated hydrocarbyl succinimide dispersant; and (d) a hydrocarbyl succinimide that has been post-treated with a post-treating agent selected from the group consisting of organic carbonates, epoxides, lactones, hydroxyaliphatic carboxylic acids, and combinations thereof.

[16] The method according to

[15] , wherein the hydrocarbyl succinimide is a polyisobutenyl bissuccinimide derived from a polyisobutylene group having a number average molecular weight of about 700 to about 2,500.

[17] The method according to

[15] , wherein the boronated hydrocarbyl succinimide is a boronated polyisobutenyl bissuccinimide derived from a polyisobutylene group having a number average molecular weight of about 700 to about 2,500.

[18] The method according to

[15] , wherein the hydrocarbyl succinimide (d) is post-treated with an organic carbonate, which is ethylene carbonate.

[19] The lubricating oil composition about 0.5 wt % to about 12 wt % of a hydrocarbyl succinimide dispersant, based on the total weight of the lubricating oil composition; about 0.5 wt. % to about 12 wt. % of a boronated hydrocarbyl succinimide dispersant, based on the total weight of the lubricating oil composition; and about 0.5 wt. % to about 12 wt. % of a hydrocarbyl succinimide post-treated with a post-treating agent selected from the group consisting of organic carbonates, epoxides, lactones, and hydroxyaliphatic carboxylic acids, based on the total weight of the lubricating oil composition. The method according to

[15] , comprising:

[20] 15. The method of claim 14, wherein the lubricating oil composition further comprises at least one additive selected from antioxidants, metal detergents, rust inhibitors, dehazing agents, demulsifiers, metal deactivators, friction modifiers, pour point depressants, antifoam agents, co-solvents, corrosion inhibitors, multifunctional agents, dyes, extreme pressure agents, and mixtures thereof. DETAILED DESCRIPTION OF THE INVENTION

[0018] To facilitate understanding of the subject matter disclosed herein, certain terms, abbreviations, or other shorthand notations used herein are defined below. Any term, abbreviation, or shorthand notation not defined will be understood to have the ordinary meaning used by those skilled in the art at the time of filing of this application.

[0019] Definition:

[0020] In this specification, the following words and expressions, if used, have the following meanings:

[0021] By "major amount" is meant greater than 50% by weight of the composition.

[0022] "Active ingredient" or "active substance" refers to an additive material that is not a diluent or solvent.

[0023] All percentages reported are weight percent on an active ingredient basis (ie, without regard to carrier or diluent oil) unless otherwise specified.

[0024] The term "ppm" means parts per million by weight based on the total weight of the lubricating oil composition.

[0025] High temperature high shear (HTHS) viscosity at 150°C was determined according to ASTM D4683.

[0026] Kinematic viscosity at 100°C (KV 100 ) was determined according to ASTM D445.

[0027] The term "metal" refers to an alkali metal, an alkaline earth metal, or a mixture thereof.

[0028] The term "alkali metal" refers to lithium, sodium, potassium, rubidium, and cesium.

[0029] The term "alkaline earth metal" refers to calcium, barium, magnesium, and strontium.

[0030] 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 alkaline products and therefore increased alkalinity. TBN was determined using the ASTM D 2896 test.

[0031] Phosphorus and sulfur contents were determined according to ASTM D5185.

[0032] The present disclosure provides (a) a major amount of about 2 to about 50 mm 2 (b) an oil of lubricating viscosity having a kinematic viscosity in the range of 1 / 2 s / sec; (b) a hydrocarbyl succinimide dispersant; (c) a boronated hydrocarbyl succinimide dispersant; and (d) a hydrocarbyl succinimide that has been post-treated with a post-treating agent selected from the group consisting of organic carbonates, epoxides, lactones, hydroxyaliphatic carboxylic acids, and combinations thereof.

[0033] Typically, the level of sulfur in the lubricating oil compositions of this disclosure is about 0.7 wt.% or less, based on the total weight of the lubricating oil composition, for example, from about 0.01 wt.% to about 0.70 wt.%, or from about 0.01 wt.% to about 0.6 wt.%, or from about 0.01 wt.% to about 0.5 wt.%, or from about 0.01 wt.% to about 0.4 wt.%, or from about 0.01 wt.% to about 0.3 wt.%, or from about 0.01 wt.% to about 0.2 wt.%, or from about 0.01 wt.% to about 0.10 wt.% of sulfur, based on the total weight of the lubricating oil composition. In one embodiment, the level of sulfur in the lubricating oil compositions of this disclosure is about 0.60 wt.% or less, about 0.50 wt.% or less, about 0.40 wt.% or less, about 0.30 wt.% or less, about 0.20 wt.% or less, or about 0.10 wt.% or less, based on the total weight of the lubricating oil composition.

[0034] In one embodiment, the level of phosphorus in the lubricating oil composition of this disclosure is about 0.12 wt. % or less, e.g., from about 0.01 wt. % to about 0.12 wt. % based on the total weight of the lubricating oil composition. In one embodiment, the level of phosphorus in the lubricating oil composition of this disclosure is about 0.11 wt. % or less, e.g., from about 0.01 wt. % to about 0.11 wt. % based on the total weight of the lubricating oil composition. In one embodiment, the level of phosphorus in the lubricating oil composition of this disclosure is about 0.10 wt. % or less, e.g., from about 0.01 wt. % to about 0.10 wt. % based on the total weight of the lubricating oil composition. In one embodiment, the level of phosphorus in the lubricating oil composition of this disclosure is about 0.09 wt. % or less, e.g., from about 0.01 wt. % to about 0.09 wt. % based on the total weight of the lubricating oil composition. In one embodiment, the level of phosphorus in the lubricating oil composition of this disclosure is about 0.08 wt. % or less, e.g., from about 0.01 wt. % to about 0.08 wt. % based on the total weight of the lubricating oil composition. In one embodiment, the level of phosphorus in the lubricating oil composition of this disclosure is about 0.07 wt. % or less, e.g., from about 0.01 wt. % to about 0.07 wt. % based on the total weight of the lubricating oil composition. In one embodiment, the level of phosphorus in the lubricating oil composition of this disclosure is about 0.05 wt. % or less, e.g., from about 0.01 wt. % to about 0.05 wt. % based on the total weight of the lubricating oil composition.

[0035] In one embodiment, the lubricating oil compositions of this disclosure produce sulfated ash levels of about 1.60 wt % or less as determined by ASTM D 874, e.g., from about 0.10 wt % to about 1.60 wt % sulfated ash as determined by ASTM D 874. In one embodiment, the lubricating oil compositions of this disclosure produce sulfated ash levels of about 1.00 wt % or less as determined by ASTM D 874, e.g., from about 0.10 wt % to about 1.00 wt % sulfated ash as determined by ASTM D 874. In one embodiment, the lubricating oil compositions of this disclosure produce sulfated ash levels of about 0.80 wt % or less as determined by ASTM D 874, e.g., from about 0.10 wt % to about 0.80 wt % sulfated ash as determined by ASTM D 874. In one embodiment, the lubricating oil compositions of this disclosure produce sulfated ash levels of less than or equal to about 0.60 wt. % as determined by ASTM D 874, such as sulfated ash levels of from about 0.10 wt. % to about 0.60 wt. % as determined by ASTM D 874.

[0036] Lubricating oil compositions according to the present disclosure comprise an oil of lubricating viscosity (sometimes referred to as a "base stock" or "base oil"). As used herein, the expression "base oil" is understood to mean a base stock or blend of base stocks that is a lubricant component produced by a single manufacturer (regardless of source or location of manufacturer) to the same specifications, conforming to the same manufacturer's specifications, and identified by a unique formula, product identification number, or both. The oil of lubricating viscosity is the primary liquid component of a lubricant, into which, for example, additives and possibly other oils are blended to produce the final lubricant (or lubricant composition). Base oils are useful for making concentrates and for making lubricating oil compositions therefrom, and may be selected from natural and synthetic lubricating oils and combinations thereof.

[0037] 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 bases. Oils of lubricating viscosity derived from coal or shale are also useful base oils.

[0038] 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), and poly(1-decene); alkylbenzenes (e.g., dodecylbenzene, tetradecylbenzene, dinonylbenzene, and di(2-ethylhexyl)benzene); alkylated naphthalenes; polyphenols (e.g., biphenyls, terphenyls, alkylated polyphenols); and alkylated diphenyl ethers and alkylated diphenyl sulfides, and their derivatives, analogs, and homologs.

[0039] Another suitable class of synthetic lubricating oils includes the esters of dicarboxylic acids (e.g., malonic acid, alkylmalonic acids, alkenylmalonic acids, succinic acid, alkylsuccinic and alkenylsuccinic acids, maleic acid, fumaric acid, azelaic acid, suberic acid, sebacic acid, adipic acid, linoleic acid dimer, and phthalic acid) with various alcohols (e.g., butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether, and 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, dieicosyl sebacate, the 2-ethylhexyl diester of linoleic acid dimer, 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.

[0040] In addition, esters useful as synthetic oils include C5 to C 12Also included are those made from monocarboxylic acids and polyols and polyol ethers such as neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol and tripentaerythritol.

[0041] Base oils may also 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 may be hydroisomerized, hydrocracked and hydroisomerized, dewaxed, or hydroisomerized and dewaxed using processes known to those skilled in the art.

[0042] In the lubricating oil composition of the present invention, unrefined oils, refined oils, and re-refined oils can be used. Unrefined oils are those obtained directly from natural or synthetic raw materials without further purification treatment. For example, shale oil obtained directly from retort operations, petroleum oil obtained directly from distillation, or ester oil obtained directly from an esterification process and used without further treatment are unrefined oils. Refined oils are similar to unrefined oils, except that they have been further treated 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.

[0043] Re-refined oils are obtained by processes similar to those used to obtain refined oils applied to refined oils that have already been used. Such re-refined oils are also known as reclaimed or reprocessed oils and are often further processed by techniques to obtain approval for used additive and oil breakdown products.

[0044] Thus, the base oils that may be used in making the present lubricating oil compositions may be selected from any of the base oils in Groups I to V as specified in the American Petroleum Institute (API) Base Oil Interchangeability Guidelines (API Publication 1509). The above base oil groups are summarized in Table 1 below. [Table 1]

[0045] Suitable base oils for use herein are any of the types corresponding to API Group II, Group III, Group IV, and Group V oils and combinations thereof, preferably Group III through Group V oils because of their exceptional volatility, stability, viscosity, and cleanliness characteristics.

[0046] The oil of lubricating viscosity for use in the lubricating oil compositions of the present disclosure, also referred to as base oil, is typically present in a major amount, e.g., greater than 50 wt.%, greater than about 70 wt.%, or greater than about 80 wt.%, based on the total weight of the lubricating oil composition. In one embodiment, the oil of lubricating viscosity may be present in the lubricating oil compositions of the present disclosure in an amount less than about 90 wt.%, or less than about 85 wt.%, based on the total weight of the lubricating oil composition. The base oil for use herein may be any oil of lubricating viscosity now known or later discovered for use in formulating lubricating oil compositions for engine oils. Additionally, the base oil for use herein may optionally contain a viscosity index improver, such as a polymeric alkyl methacrylate, an olefin-based copolymer such as an ethylene-propylene copolymer or a styrene-butadiene copolymer, and mixtures thereof. The topology of the viscosity modifier may include, but is not limited to, linear, branched, hyperbranched, star, or comb topologies.

[0047] As one skilled in the art will readily appreciate, the viscosity of a base oil will vary depending on the application. Thus, the viscosity of a base oil for use herein will typically range from about 2 centistokes to about 2000 centistokes (cSt) at 100°C. Generally, base oils used as engine oils will have kinematic viscosities ranging from about 2 cSt to about 30 cSt, or from about 3 cSt to about 16 cSt, or from about 4 cSt to about 12 cSt at 100°C, and may be selected or blended to obtain a desired grade of engine oil, for example, SAE viscosity grades of 0W, 0 Lubricating oil compositions are obtained that are 0W-8, 0W-12, 0W-16, 0W-20, 0W-26, 0W-30, 0W-40, 0W-50, 0W-60, 5W, 5W-20, 5W-30, 5W-40, 5W-50, 5W-60, 10W, 10W-20, 10W-30, 10W-40, 10W-50, 15W, 15W-20, 15W-30, 15W-40, 30, 40, etc.

[0048] The lubricating oil composition has a viscosity index of at least 135 (e.g., 135 to 400, or 135 to 250), or at least 150 (e.g., 150 to 400, or 150 to 250), or at least 165 (e.g., 165 to 400, or 165 to 250), or at least 190 (e.g., 190 to 400, or 190 to 250), or at least 200 (e.g., 200 to 400, or 200 to 250). If the viscosity index of the lubricating oil composition is less than 135, it may be difficult to improve fuel efficiency while maintaining the HTHS viscosity at 150°C. If the viscosity index of the lubricating oil composition is greater than 400, evaporation characteristics may be reduced, and defects due to insufficient solubility of additives and matching characteristics with sealing materials may be induced.

[0049] The lubricating oil composition according to the present disclosure further comprises a hydrocarbyl succinimide dispersant. Hydrocarbyl succinimide dispersants generally include, for example, hydrocarbyl mono- and polysuccinimides. Certain basic types of succinimides and related materials encompassed by the term "succinimide" are taught in U.S. Pat. Nos. 3,172,892, 3,219,666, and 3,272,746, the disclosures of which are incorporated herein by reference. The term "succinimide" is understood in the art to encompass many of the amide, imide, and amidine species that may also be formed. However, the primary product is succinimide, and the term is generally accepted to refer to the product of the reaction of a hydrocarbyl succinic acid or anhydride with a nitrogen-containing compound.

[0050] In one embodiment, the hydrocarbyl succinimides are those succinimides prepared from hydrocarbyl succinic anhydrides and polyamines due to their commercial availability. For example, suitable anhydrides have the formula I: [ka] wherein R is a hydrocarbyl group containing from about 12 to about 350 carbon atoms. Polyamines suitable for use in preparing the succinimides include, for example, polyalkylene polyamines, including polyalkylenediamines. Such polyalkylene polyamines will typically contain from about 2 to about 12 nitrogen atoms and from about 2 to 24 carbon atoms. In one embodiment, suitable polyalkylene polyamines have the formula: HN-(R 1 NH) c -H, wherein R 1 is a straight or branched chain alkylene group having 2 or 3 carbon atoms and c is 1 to 9. Representative examples of suitable polyalkylene polyamines include ethylenediamine, diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, and mixtures thereof.

[0051] Many of the polyamines suitable for use in the present invention are commercially available, and others can be prepared by methods well known in the art. For example, methods for preparing amines and their reactions are described in detail in Sidgewick, "The Organic Chemistry of Nitrogen," Clarendon Press, Oxford, 1966; Noller, "Chemistry of Organic Compounds," Saunders, Philadelphia, 2nd ed., 1957; and Kirk-Othmer, "Encyclopedia of Chemical Technology," 2nd ed., especially Vol. 2, pp. 99-116.

[0052] In one exemplary embodiment, the hydrocarbyl succinimide dispersant is obtained by the reaction of polyisobutenyl succinic anhydride (PIBSA) with a polyamine. In another embodiment, the hydrocarbyl succinimide dispersant is obtained by the reaction of PIBSA with a polyamine, the PIBSA being produced from polybutene and maleic anhydride (e.g., by a thermal reaction process that does not use chlorine or chlorine-containing compounds). In another embodiment, the hydrocarbyl succinimide dispersant is the succinimide reaction product of the condensation reaction between PIBSA and one or more alkylene polyamines. In this embodiment, the PIBSA can be the thermal reaction product of high methylvinylidene polyisobutene (PIB) with maleic anhydride.

[0053] In one embodiment, the hydrocarbyl succinimide dispersant is a predominantly bissuccinimide reaction product derived from PIB having a number average molecular weight (Mn) of about 500 to about 3000. In one embodiment, the PIB has an Mn of about 700 to 2700. In another embodiment, the hydrocarbyl succinimide dispersant is a predominantly bissuccinimide reaction product derived from PIB having a Mn of at least about 600, or at least about 800, or at least about 1000, or at least about 1100, or at least about 1200, or at least about 1300, or at least about 1400, or at least about 1500, or at least about 1600, or at least about 1700, or at least about 1800, or at least about 1900, or at least about 2000, or at least about 2100, or at least about 2200, or at least about 2300, or at least about 2400, or at least about 2500, or at least about 2600, or at least about 2700, or at least about 2800, or at least about 2900, or at least about 3000. In another embodiment, the hydrocarbyl succinimide dispersant is a predominantly bissuccinimide reaction product derived from PIB having an Mn of 5000 or less, or about 4000 or less, or about 3500 or less, or about 3000 or less, or about 2700 or less, or about 2500 or less.

[0054] In one embodiment, the hydrocarbyl succinimide is prepared from polyisobutenyl succinic anhydride of about 70 to about 128 carbon atoms and tetraethylenepentamine or triethylenetetramine or mixtures thereof.

[0055] Methods for preparing hydrocarbyl succinimide dispersants are well known in the art. For example, one or more hydrocarbyl succinic acids or anhydrides and one or more amines can be heated, optionally in the presence of a substantially inert organic liquid solvent / diluent, to remove water. The reaction temperature can range from about 80°C to the decomposition temperature of the mixture or product, which is typically between about 100°C and about 300°C. The amount of hydrocarbyl succinic acid or anhydride used in the reaction can range from about 30 to about 95% by weight, or from about 40 to about 60% by weight, based on the total weight of the reaction mixture. Additional details and examples of procedures for preparing hydrocarbyl succinimide dispersants include those described, for example, in U.S. Patent Nos. 3,172,892, 3,219,666, 3,272,746, 4,234,435, 6,165,235, and 6,440,905.

[0056] Typically, the hydrocarbyl succinimide dispersant is present in lubricating oil compositions according to this disclosure in an amount of from about 0.5 wt % to about 12 wt %, based on the total weight of the lubricating oil composition. In another embodiment, the hydrocarbyl succinimide dispersant is present in lubricating oil compositions according to this disclosure in an amount of from about 0.5 wt % to about 5 wt %, based on the total weight of the lubricating oil composition. In another embodiment, the hydrocarbyl succinimide dispersant is present in lubricating oil compositions according to this disclosure in an amount of from about 0.5 wt % to about 4 wt %, based on the total weight of the lubricating oil composition.

[0057] The lubricating oil composition according to the present disclosure further comprises a boronated hydrocarbyl succinimide dispersant. Typically, the boronated hydrocarbyl succinimide dispersant is a hydrocarbyl succinimide dispersant that has been treated with a boron source known in the art. Typically, hydrocarbyl succinimide dispersants that have been post-treated with a boron source include, for example, hydrocarbyl mono- and polysuccinimides. As noted above, certain basic types of succinimides and related materials encompassed by the term "succinimide" are taught in U.S. Pat. Nos. 3,172,892; 3,219,666; and 3,272,746, the disclosures of which are incorporated herein by reference.

[0058] In one embodiment, the hydrocarbyl succinimides are those succinimides prepared from hydrocarbyl succinic anhydrides and polyamines due to their commercial availability. Methods for preparing hydrocarbyl succinimide dispersants are well known in the art, as described above. For example, suitable anhydrides can be represented by Formula I: [ka] wherein R is a hydrocarbyl group containing from about 12 to about 350 carbon atoms. Polyamines suitable for use in preparing the succinimides include, for example, polyalkylene polyamines, including polyalkylenediamines. Such polyalkylene polyamines will typically contain from about 2 to about 12 nitrogen atoms and from about 2 to 24 carbon atoms. In one embodiment, suitable polyalkylene polyamines have the formula: HN-(R 1 NH) c -H, wherein R 1is a straight or branched chain alkylene group having 2 or 3 carbon atoms, and c is 1 to 9. Representative examples of suitable polyalkylene polyamines include ethylenediamine, diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, and mixtures thereof. Many of the polyamines suitable for use in the present invention are commercially available; others can be prepared by methods well known in the art, as described above.

[0059] In one exemplary embodiment, the hydrocarbyl succinimide dispersant post-treated with a boron source is obtained by reacting PIBSA with a polyamine. In another embodiment, the hydrocarbyl succinimide dispersant post-treated with a boron source is obtained by reacting PIBSA with a polyamine, the PIBSA being produced from polybutene and maleic anhydride (e.g., by a thermal reaction process that does not use chlorine or chlorine-containing compounds). In another embodiment, the hydrocarbyl succinimide dispersant post-treated with a boron source is the succinimide reaction product of a condensation reaction between PIBSA and one or more alkylene polyamines. In this embodiment, the PIBSA can be the thermal reaction product of high methylvinylidene polyisobutene (PIB) and maleic anhydride.

[0060] In one embodiment, the hydrocarbyl succinimide dispersant post-treated with a boron source is primarily a bissuccinimide reaction product derived from PIB having a number average molecular weight (Mn) of about 500 to about 3000. In one embodiment, the PIB has an Mn of about 700 to 2700. In another embodiment, the hydrocarbyl succinimide dispersant that is post-treated with a boron source is primarily a bissuccinimide reaction product derived from PIB having a Mn of at least about 600, or at least about 800, or at least about 1000, or at least about 1100, or at least about 1200, or at least about 1300, or at least about 1400, or at least about 1500, or at least about 1600, or at least about 1700, or at least about 1800, or at least about 1900, or at least about 2000, or at least about 2100, or at least about 2200, or at least about 2300, or at least about 2400, or at least about 2500, or at least about 2600, or at least about 2700, or at least about 2800, or at least about 2900, or at least about 3000. In another embodiment, the hydrocarbyl succinimide dispersant that is post-treated with a boron source is primarily a bissuccinimide reaction product derived from PIB having an Mn of 5000 or less, or about 4000 or less, or about 3500 or less, or about 3000 or less, or about 2700 or less, or about 2500 or less.

[0061] In one embodiment, the hydrocarbyl succinimide that is post-treated with a boron source is prepared from a polyisobutenyl succinic anhydride of from about 70 to about 128 carbon atoms and tetraethylenepentamine or triethylenetetramine or a mixture thereof.

[0062] In one embodiment, the boronated hydrocarbyl succinimide dispersant is a hydrocarbyl succinimide dispersant previously described that has been treated with a boron source such that the boronated hydrocarbyl succinimide dispersant contains up to 3 wt.% boron. In one embodiment, the boronated hydrocarbyl succinimide dispersant may contain up to about 2 wt.% boron. In one embodiment, the boronated hydrocarbyl succinimide dispersant may contain up to about 1 wt.% boron. In one embodiment, the boronated hydrocarbyl succinimide dispersant may contain up to about 0.8 wt.% boron. In one embodiment, the boronated hydrocarbyl succinimide dispersant may contain about 0.1 wt.% or greater boron. In one embodiment, the boronated hydrocarbyl succinimide dispersant may contain about 0.5 wt.% or greater boron. In one embodiment, the boronated hydrocarbyl succinimide dispersant may contain from about 0.1 to about 3 weight percent boron.

[0063] Suitable boron compounds that can be used as boron sources include, for example, boric acid, borate salts, borate esters, etc. Representative examples of boric acid include orthoboric acid, metaboric acid, paraboric acid, etc. Representative examples of borates include ammonium borates such as ammonium metaborate, ammonium tetraborate, ammonium pentaborate, and ammonium octaborate. Representative examples of borate esters include monomethyl borate, dimethyl borate, trimethyl borate, monoethyl borate, diethyl borate, triethyl borate, monopropyl borate, dipropyl borate, tripropyl borate, monobutyl borate, dibutyl borate, tributyl borate, etc.

[0064] Generally, the boronated hydrocarbyl succinimide dispersant is present in lubricating oil compositions according to this disclosure in an amount of from about 0.5 to about 12 wt. %, based on the total weight of the lubricating oil composition. In another embodiment, the boronated hydrocarbyl succinimide dispersant is present in lubricating oil compositions according to this disclosure in an amount of from about 0.5 to about 5 wt. %, based on the total weight of the lubricating oil composition. In another embodiment, the boronated hydrocarbyl succinimide dispersant is present in lubricating oil compositions according to this disclosure in an amount of from about 0.5 to about 4 wt. %, based on the total weight of the lubricating oil composition.

[0065] The lubricating oil composition according to the present disclosure further comprises a hydrocarbyl succinimide post-treated with a post-treating agent selected from the group consisting of organic carbonates, epoxides, lactones, hydroxyaliphatic carboxylic acids, and combinations thereof. Typically, hydrocarbyl succinimide dispersants post-treated with the aforementioned post-treating agents include, for example, hydrocarbyl mono- and polysuccinimides. As noted above, certain basic types of succinimides and related materials encompassed by the term "succinimide" are taught in U.S. Pat. Nos. 3,172,892; 3,219,666; and 3,272,746, the disclosures of which are incorporated herein by reference.

[0066] In one embodiment, the hydrocarbyl succinimides are those succinimides prepared from hydrocarbyl succinic anhydrides and polyamines due to their commercial availability. Methods for preparing hydrocarbyl succinimide dispersants are well known in the art, as described above. For example, suitable anhydrides can be represented by Formula I: [ka] wherein R is a hydrocarbyl group containing from about 12 to about 350 carbon atoms. Polyamines suitable for use in preparing the succinimides include, for example, polyalkylene polyamines, including polyalkylenediamines. Such polyalkylene polyamines will typically contain from about 2 to about 12 nitrogen atoms and from about 2 to 24 carbon atoms. In one embodiment, suitable polyalkylene polyamines have the formula: HN-(R 1 NH) c -H, wherein R 1 is a straight or branched chain alkylene group having 2 or 3 carbon atoms, and c is 1 to 9. Representative examples of suitable polyalkylene polyamines include ethylenediamine, diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, and mixtures thereof. Many of the polyamines suitable for use in the present invention are commercially available; others can be prepared by methods well known in the art, as described above.

[0067] In one exemplary embodiment, the hydrocarbyl succinimide dispersant post-treated with the aforementioned post-treating agent is obtained by reacting PIBSA with a polyamine. In another embodiment, the hydrocarbyl succinimide dispersant post-treated with the aforementioned post-treating agent is obtained by reacting PIBSA with a polyamine, the PIBSA being produced from polybutene and maleic anhydride (e.g., by a thermal reaction process that does not use chlorine or chlorine-containing compounds). In another embodiment, the hydrocarbyl succinimide dispersant post-treated with the aforementioned post-treating agent is the succinimide reaction product of a condensation reaction between PIBSA and one or more alkylene polyamines. In this embodiment, the PIBSA can be the thermal reaction product of high methylvinylidene polyisobutene (PIB) and maleic anhydride.

[0068] In one embodiment, the hydrocarbyl succinimide dispersant post-treated with the above-described post-treating agents is primarily a bissuccinimide reaction product derived from PIB having a number average molecular weight (Mn) of about 500 to about 3000. In one embodiment, the PIB has an Mn of about 700 to 2700. In another embodiment, the hydrocarbyl succinimide dispersant post-treated with the aforementioned post-treating agents is primarily a bissuccinimide reaction product derived from PIB having a Mn of at least about 600, or at least about 800, or at least about 1000, or at least about 1100, or at least about 1200, or at least about 1300, or at least about 1400, or at least about 1500, or at least about 1600, or at least about 1700, or at least about 1800, or at least about 1900, or at least about 2000, or at least about 2100, or at least about 2200, or at least about 2300, or at least about 2400, or at least about 2500, or at least about 2600, or at least about 2700, or at least about 2800, or at least about 2900, or at least about 3000. In another embodiment, the hydrocarbyl succinimide dispersant that is post-treated with the aforementioned post-treating agents is primarily a bissuccinimide reaction product derived from PIB having an Mn of 5000 or less, or about 4000 or less, or about 3500 or less, or about 3000 or less, or about 2700 or less, or about 2500 or less.

[0069] In one embodiment, the hydrocarbyl succinimide that is post-treated with the above-described post-treating agent is prepared from a polyisobutenyl succinic anhydride of from about 70 to about 128 carbon atoms and tetraethylenepentamine or triethylenetetramine or a mixture thereof.

[0070] Suitable organic carbonates include, for example, 1,3-dioxolan-2-one (ethylene carbonate); 4-methyl-1,3-dioxolan-2-one (propylene carbonate); 4-ethyl-1,3-dioxolan-2-one (butylene carbonate); 4-hydroxymethyl-1,3-dioxolan-2-one; 4,5-dimethyl-1,3-dioxolan-2-one; 4-ethyl-1,3-dioxolan-2-one; 4,4-dimethyl-1,3-dioxolan-2-one; 4-methyl-5-ethyl-1,3-dioxolan-2-one; 4,5-diethyl-1,3-dioxolan-2-one; 4,4-diethyl-1,3-dioxolan-2-one; 1,3-dioxan-2-one; 4,4-dimethyl-1,3-dioxan- 5-hydroxymethyl-5-methyl-1,3-dioxan-2-one; 5,5-diethyl-1,3-dioxan-2-one; 5-methyl-5-propyl-1,3-dioxan-2-one; 4,6-dimethyl-1,3-dioxan-2-one; 4,4,6-trimethyl-1,3-dioxan-2-one and cyclic carbonates such as spiro[1,3-oxa-2-cyclohexanone-5,5'-1',3'-oxa-2'-cyclohexanone]. Other suitable cyclic carbonates can be prepared from saccharides such as sorbitol, glucose, fructose, galactose, and the like, and from C1 to C6 by methods known in the art. 30 They can be prepared from vicinal diols prepared from olefins.

[0071] Suitable epoxides include, for example, those having the following structure: [ka] (In the formula, R 1 , R 2 , R 3 and R 4may be independently hydrogen or a hydrocarbyl group containing 1 to 50 carbon atoms. In one embodiment, suitable epoxides include, for example, ethylene oxide, propylene oxide, butylene oxide, styrene oxide, and combinations thereof.

[0072] Suitable lactones include, for example, those having from 3 to about 12 carbon atoms in the main ring. In one embodiment, a suitable lactone is, for example, caprolactone. Other cyclic lactones for use herein may be those disclosed in, for example, U.S. Patent Nos. 4,617,138, 4,645,515, 4,668,246, 4,963,275, and 4,971,711.

[0073] Suitable hydroxyaliphatic carboxylic acids include, for example, those having the following structure: R 5 -CH(OH)-COOH (In the formula, R 5 is a hydrocarbyl group having 1 to about 30 carbon atoms. Representative examples of alpha-hydroxyaliphatic carboxylic acid compounds include alpha-hydroxydodecanoic acid, alpha-hydroxytetradecanoic acid, alpha-hydroxyhexadecanoic acid, alpha-hydroxyoctadecanoic acid, alpha-hydroxypentadecanoic acid, alpha-hydroxyeicosanoic acid, alpha-hydroxydocosanoic acid, alpha-hydroxytetracosanoic acid, alpha-hydroxyhexacosanoic acid, alpha-hydroxyoctacosanoic acid, and the like. Other hydroxyaliphatic carboxylic acids may be those disclosed in U.S. Patent Nos. 4,482,464, 4,521,318, and 4,713,189.

[0074] Methods for preparing hydrocarbyl succinimides post-treated with a post-treating agent selected from the group consisting of organic carbonates, epoxides, lactones, hydroxyaliphatic carboxylic acids, and combinations thereof are well known in the art. For example, the post-treatment of a cyclic carbonate can be carried out under conditions sufficient to cause reaction between the cyclic carbonate and the secondary amino group of the polyamino substituent. Typically, the reaction is carried out at a temperature of about 0°C to about 250°C, or about 100°C to about 200°C. The reaction can be carried out methodically, with or without the presence of a catalyst (such as an acidic, basic, or Lewis acid catalyst). Depending on the viscosity of the reactants, it may be desirable to carry out the reaction using an inert organic solvent or diluent, such as toluene or xylene.

[0075] Typically, the hydrocarbyl succinimide post-treated with a post-treating agent selected from the group consisting of organic carbonates, epoxides, lactones, hydroxyaliphatic carboxylic acids, and combinations thereof is present in the lubricating oil compositions according to the present disclosure in an amount of from about 0.5 wt % to about 12 wt %, based on the total weight of the lubricating oil composition. In another embodiment, the hydrocarbyl succinimide post-treated with a post-treating agent selected from the group consisting of organic carbonates, epoxides, lactones, hydroxyaliphatic carboxylic acids, and combinations thereof is present in the lubricating oil compositions according to the present disclosure in an amount of from about 0.5 wt % to about 5 wt %, based on the total weight of the lubricating oil composition. In another embodiment, the hydrocarbyl succinimide post-treated with a post-treating agent selected from the group consisting of organic carbonates, epoxides, lactones, hydroxyaliphatic carboxylic acids, and combinations thereof is present in the lubricating oil compositions according to the present disclosure in an amount of from about 0.5 wt % to about 4 wt %, based on the total weight of the lubricating oil composition.

[0076] In general, a dispersant mixture of a hydrocarbyl succinimide dispersant; (c) a borated hydrocarbyl succinimide dispersant; and (d) a hydrocarbyl succinimide post-treated with a post-treating agent selected from the group consisting of organic carbonates, epoxides, lactones, hydroxyaliphatic carboxylic acids, and combinations thereof, can provide a lubricating oil composition with a TBN of from about 0.5 to about 5. In one embodiment, a dispersant mixture of a hydrocarbyl succinimide dispersant; (c) a borated hydrocarbyl succinimide dispersant; and (d) a hydrocarbyl succinimide post-treated with a post-treating agent selected from the group consisting of organic carbonates, epoxides, lactones, hydroxyaliphatic carboxylic acids, and combinations thereof, can provide a lubricating oil composition with a TBN of from about 0.9 to about 4.2.

[0077] The lubricating oil compositions of the present disclosure may also contain other conventional additives capable of imparting or improving any desirable properties of the lubricating oil composition in which these additives are dispersed or dissolved. Any additive known to those skilled in the art may 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 be blended with antioxidants, detergents such as metal detergents, rust inhibitors, dehazing agents, demulsifiers, metal deactivators, friction modifiers, antiwear agents, pour point depressants, antifoam agents, cosolvents, corrosion inhibitors, dyes, extreme pressure agents, and the like, and mixtures thereof. A variety of additives are known and commercially available. These additives or their analogues can be used in preparing the lubricating oil compositions of the present invention by conventional blending procedures.

[0078] Representative examples of metal detergents include sulfonates, alkylphenates, sulfurized alkylphenates, carboxylates, salicylates, phosphonates, and phosphinates. Commercially available products are generally neutral or overbased. Overbased metal detergents are generally produced by carbonate a mixture of a hydrocarbon, a detergent acid (e.g., sulfonic acid, alkylphenol, carboxylate), a metal oxide or hydroxide (e.g., calcium oxide or calcium hydroxide), and a promoter such as xylene, methanol, or water. For example, to prepare overbased calcium sulfonate, carbonation involves reacting calcium oxide or calcium hydroxide with gaseous carbon dioxide to form calcium carbonate. The sulfonic acid is neutralized with excess CaO or Ca(OH)2 to form the sulfonate salt.

[0079] In one embodiment, the one or more overbased detergents may have a TBN (oil-free basis) of from 0 to about 60. In another embodiment, the one or more overbased detergents may have a TBN (oil-free basis) of from greater than 60 to about 200. In another embodiment, the one or more overbased detergents may have a TBN (oil-free basis) of from greater than 200 to about 800.

[0080] Examples of antiwear agents include, but are not limited to, zinc dialkyldithiophosphates and zinc diaryldithiophosphates, such as those described in the article by Born et al. entitled "Relationship between Chemical Structure and Effectiveness of Some Metallic Dialkyl- and Diaryl-dithiophosphates in Different Lubricated Mechanisms," published in Lubrication Science 4-2, January 1992 (see, for example, pages 97-100), aryl phosphates and phosphites, sulfur-containing esters, phosphosulfur compounds, metal or ashless dithiocarbamates, xanthates, alkyl sulfides, and the like, and mixtures thereof.

[0081] In preparing lubricating oil formulations, it is common practice to incorporate the additives in the form of a concentrate of about 10 to about 80 weight percent active ingredient in a hydrocarbon oil, such as mineral lubricating oil, or other suitable solvent.

[0082] Typically, these concentrates can be diluted with about 3 to about 100 parts by weight, e.g., about 5 to about 40 parts by weight, of lubricating oil per part by weight of additive package in forming a finished lubricant, e.g., crankcase motor oil. The purpose of the concentrate, of course, is to make the various materials easier and more convenient to handle and to facilitate dissolution or dispersion in the final blend.

[0083] Each of the foregoing additives is used in a functionally effective amount to impart the desired characteristics to the lubricant when used. 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 characteristics to the lubricant.

[0084] Generally, the concentration of each additive in the lubricating oil composition, when used, can range from about 0.001% to about 20% by weight, or from about 0.005% to about 15% by weight, or from about 0.01% to about 10% by weight, or from about 0.1% to about 5% by weight, or from about 0.1% to about 2.5% by weight, based on the total weight of the lubricating oil composition. Furthermore, the total amount of additives in the lubricating oil composition can range from about 0.001% to about 20% by weight, or from about 0.01% to about 10% by weight, or from about 0.1% to about 5% by weight, based on the total weight of the lubricating oil composition.

[0085] The following examples are presented to illustrate embodiments of the present disclosure, but are not intended to limit the disclosure to the specific embodiments described. Specific details described in each example should not be construed as necessary features of the disclosure. The following examples are for illustrative purposes only and are not intended to limit the scope of the disclosure in any way. 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 disclosure.

[0086] Preparation of Dispersant A

[0087] A succinimide-type dispersant was prepared by a thermal reaction process using polybutene with a number-average molecular weight of about 1,300 and maleic anhydride, and then reacting it with a polyalkylenepolyamine having an average number of nitrogen atoms of 6.5 (per molecule).

[0088] Preparation of Dispersant B

[0089] In accordance with U.S. Pat. No. 5,356,552, a boronated succinimide dispersant was prepared by a thermal reaction process using polybutene having a number average molecular weight of about 1,300 and maleic anhydride, reacting with a polyalkylene polyamine having an average of 6.5 nitrogen atoms per molecule, and treating the resulting succinimide with boric acid.

[0090] Preparation of Dispersant C

[0091] In accordance with U.S. Pat. No. 5,356,552, an ethylene carbonate-treated succinimide-type dispersant was prepared by a thermal reaction process using polybutene having a number average molecular weight of about 2,300 and maleic anhydride, reacting with a polyalkylene polyamine having an average number of nitrogen atoms of 6.5 (per molecule), and treating the resulting succinimide with ethylene carbonate.

[0092] Example 1 Lubricating oil compositions were prepared containing a major amount of a base oil of lubricating viscosity and the following additives to provide a finished oil having an SAE viscosity of 15W-40:

[0093] 1.30 wt. % Dispersant A;

[0094] 1.05 wt% Dispersant B;

[0095] 0.95 wt% Dispersant C;

[0096] A mixture of calcium sulfonate and phenate detergents;

[0097] secondary zinc dialkyldithiophosphate with a phosphorus content of 990 ppm;

[0098] Molybdenum succinimide antioxidant;

[0099] Alkylated diphenylamines;

[0100] 5 ppm of antifoaming agent, calculated as silicon content;

[0101] a non-dispersant olefin copolymer viscosity modifier; and

[0102] Remainder, Group II base oils;

[0103] Here, the TBN in the lubricating oil composition from Dispersants A, B and C is 2.21.

[0104] Comparative Example 1 Lubricating oil compositions were prepared containing a major amount of a base oil of lubricating viscosity and the following additives to provide a finished oil having an SAE viscosity of 15W-40:

[0105] 2.85 wt% Dispersant C;

[0106] A mixture of calcium sulfonate and phenate detergents;

[0107] secondary zinc dialkyldithiophosphate with a phosphorus content of 990 ppm;

[0108] Molybdenum succinimide antioxidant;

[0109] Alkylated diphenylamines;

[0110] 5 ppm of antifoaming agent, calculated as silicon content;

[0111] a non-dispersant olefin copolymer viscosity modifier; and

[0112] Remainder, Group II base oils;

[0113] Here, the TBN in the lubricating oil composition from Dispersants A, B and C is 0.94.

[0114] Comparative Example 2 Lubricating oil compositions were prepared containing a major amount of a base oil of lubricating viscosity and the following additives to provide a finished oil having an SAE viscosity of 15W-40:

[0115] 3.89 wt% Dispersant A;

[0116] A mixture of calcium sulfonate and phenate detergents;

[0117] secondary zinc dialkyldithiophosphate with a phosphorus content of 990 ppm;

[0118] Molybdenum succinimide antioxidant;

[0119] Alkylated diphenylamines;

[0120] 5 ppm of antifoaming agent, calculated as silicon content;

[0121] a non-dispersant olefin copolymer viscosity modifier; and

[0122] Remainder, Group II base oils;

[0123] Here, the TBN in the lubricating oil composition from Dispersants A, B and C is 3.22.

[0124] Comparative Example 3 Lubricating oil compositions were prepared containing a major amount of a base oil of lubricating viscosity and the following additives to provide a finished oil having an SAE viscosity of 15W-40:

[0125] 3.15 wt% Dispersant B;

[0126] A mixture of calcium sulfonate and phenate detergents;

[0127] secondary zinc dialkyldithiophosphate with a phosphorus content of 990 ppm;

[0128] Molybdenum succinimide antioxidant;

[0129] Alkylated diphenylamines;

[0130] 5 ppm of antifoaming agent, calculated as silicon content;

[0131] a non-dispersant olefin copolymer viscosity modifier; and

[0132] Remainder, Group II base oils;

[0133] Here, the TBN in the lubricating oil composition from Dispersants A, B and C is 2.47.

[0134] T-8E Screener Test

[0135] The Mack T-8E screener was based on a Mack T-11 engine and operated for 144 hours with near-zero EGR. The same temperature, speed, and fuel conditions were used as for the T-11 (ASTM D7156), except that the target soot was set at 4% after 108 hours. KV100 and soot were measured by TGA every 12 hours, as well as the initial KV100 shear viscosity after 30 cycles, allowing the RV100 at 100% soot to be calculated.

[0136] Heavy-duty commercial diesel soot treatment Mack T8 Test

[0137] The Mack T8 engine test is an established test for determining a lubricant's ability to control viscosity changes caused by soot, which is produced as a by-product from the combustion process in modern heavy-duty truck diesel engines. The test also evaluates sludge and oil consumption. The key parameter is the lubricant's viscosity increase at 4% soot in oil, as measured by thermogravimetric analysis (TGA). The required level of soot may be achieved before the end of the test (250 hours). At the end of the test, the soot and viscosity increase are measured. These measurements are used as a measure of oil performance. [Table 2]

[0138] In Table 1 below, the relative performance of the lubricating oil composition of Example 1 is compared to the lubricating oil compositions of Comparative Examples 1-3 according to the Screener Mack T8 test.

[0139] Fluorocarbon Elastomer Seal Compatibility (AK6)

[0140] The lubricating oil compositions of Example 1 and Comparative Examples 1-3 were tested for compatibility with fluorocarbon elastomer seals in a Daimler Chrysler bench test (PV 3344) by suspending fluorocarbon test specimens (AK 6) in an oil solution heated to 150°C for 168 hours. The variations in volume change, hardness change point (PH), tensile strength change (TS), and elongation change (EL) for each sample were measured. These pass limits are summarized below. [Table 3] The test results of the compatibility test are summarized in Table 1 below. [Table 4]

[0141] It should be understood that various modifications may be made to the embodiments disclosed herein. Accordingly, the above description should not be construed as limiting, but merely as exemplifications of preferred embodiments. For example, the functions described above and implemented as the best mode for operating the invention are for illustrative purposes only. Other arrangements and methods may be implemented by those skilled in the art without departing from the scope and spirit of the invention. Moreover, those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.

Claims

1. (a) Major amount of 2 to 50 mm at 100°C ２ an oil of lubricating viscosity having a kinematic viscosity in the range of 1 / 2000 kJ / sec; (b) 0.5 wt % to 12 wt % of a hydrocarbyl succinimide dispersant, based on the total weight of the lubricating oil composition, wherein the hydrocarbyl succinimide is a polyisobutenyl bissuccinimide; (c) 0.5 wt % to 12 wt % of a boronated hydrocarbyl succinimide dispersant, based on the total weight of the lubricating oil composition; and (d) a hydrocarbyl succinimide post-treated with 0.5 wt. % to 12 wt. % of a post-treating agent selected from the group consisting of organic carbonates, epoxides, lactones, hydroxyaliphatic carboxylic acids, and combinations thereof, based on the total weight of the lubricating oil composition. A lubricating oil composition for diesel engines comprising:

2. 10. The lubricating oil composition of claim 1, wherein the major amount of oil of lubricating viscosity is greater than 50 wt. %, based on the total weight of the lubricating oil composition.

3. 2. The lubricating oil composition of claim 1, wherein the hydrocarbyl group of the hydrocarbyl succinimide dispersant contains from 12 to 350 carbon atoms.

4. 2. The lubricating oil composition of claim 1, wherein the polyisobutenyl bissuccinimide is derived from a polyisobutylene group having a number average molecular weight of 700 to 2500.

5. 10. The lubricating oil composition of claim 1, wherein the borated hydrocarbyl succinimide dispersant is a borated polyalkenyl succinimide.

6. 6. The lubricating oil composition of claim 5, wherein the boronated polyalkenyl succinimide is a boronated polyisobutenyl bissuccinimide.

7. 2. The lubricating oil composition of claim 1, wherein the boronated polyisobutenyl bissuccinimide is derived from a polyisobutylene group having a number average molecular weight of 700 to 2500.

8. 10. The lubricating oil composition of claim 1, wherein the hydrocarbyl succinimide (d) is post-treated with an organic carbonate.

9. 9. The lubricating oil composition of claim 8, wherein the organic carbonate is ethylene carbonate.

10. 2. The lubricating oil composition of claim 1, wherein the mixture of the hydrocarbyl succinimide dispersant; the boronated hydrocarbyl succinimide dispersant; and the hydrocarbyl succinimide post-treated with a post-treating agent selected from the group consisting of organic carbonates, epoxides, lactones, hydroxyaliphatic carboxylic acids, and combinations thereof provides a total base number (TBN) of 0.5 to 5 to the lubricating oil composition.

11. 10. The lubricating oil composition of claim 1, further comprising at least one additive selected from antioxidants, metal detergents, rust inhibitors, dehazing agents, demulsifiers, metal deactivators, friction modifiers, pour point depressants, antifoam agents, co-solvents, corrosion inhibitors, multifunctional agents, dyes, extreme pressure agents, and mixtures thereof.

12. (a) Major amount of 2 to 50 mm at 100°C ２ 1. A method of operating a diesel engine with a lubricating oil composition comprising: (a) an oil of lubricating viscosity having a kinematic viscosity in the range of 1 / 2 second to 1 / 4 second; (b) from 0.5 wt. % to 12 wt. % of a hydrocarbyl succinimide dispersant, based on the total weight of the lubricating oil composition, wherein the hydrocarbyl succinimide is a polyisobutenyl bissuccinimide; (c) from 0.5 wt. % to 12 wt. % of a boronated hydrocarbyl succinimide dispersant, based on the total weight of the lubricating oil composition; and (d) from 0.5 wt. % to 12 wt. % of a hydrocarbyl succinimide that has been post-treated with an after-treating agent selected from the group consisting of organic carbonates, epoxides, lactones, hydroxyaliphatic carboxylic acids, and combinations thereof, based on the total weight of the lubricating oil composition.

13. 13. The method of claim 12, wherein the hydrocarbyl succinimide is a polyisobutenyl bissuccinimide derived from a polyisobutylene group having a number average molecular weight of 700 to 2500.

14. 13. The method of claim 12, wherein the boronated hydrocarbyl succinimide is a boronated polyisobutenyl bissuccinimide derived from a polyisobutylene group having a number average molecular weight of 700 to 2500.

15. 13. The method of claim 12, wherein the hydrocarbyl succinimide (d) is post-treated with an organic carbonate that is ethylene carbonate.

16. 13. The method of claim 12, wherein the lubricating oil composition further comprises at least one additive selected from antioxidants, metal detergents, rust inhibitors, dehazing agents, demulsifiers, metal deactivators, friction modifiers, pour point depressants, antifoam agents, co-solvents, corrosion inhibitors, multifunctional agents, dyes, extreme pressure agents, and mixtures thereof.

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