Lubricating composition for a vehicle transmission

Abstract

To provide a lubricating composition for a transmission, an axle, a tractor, or an industrial gear, which achieves desired load-bearing capacity while achieving improved copper corrosion performance, and a method for lubricating a transmission.SOLUTION: A lubricating composition suitable for use in a transmission of a vehicle, the lubricating composition comprising one or more base oils of lubricating viscosity, at least about 0.35 weight percent of a thiadiazole additive, and one or more substituted trisaryl phosphites having an overall ratio of para-substituted to ortho-substituted between about 0.5 and about 2.0.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to lubricating compositions for transmissions, axles, tractors, or industrial gears that achieve desired load-bearing capabilities while achieving improved copper corrosion performance. [Background technology]

[0002] Transmissions, axles, tractors, and industrial gears generally require lubricants that provide specific performance characteristics suitable for the desired application. Typically, lubricants for such applications may require fluids that meet one or more performance characteristics, such as extreme pressure, antiwear, friction, and / or copper corrosion, although these may suggest only some of the general requirements of the fluid. To achieve such performance, various additives may be included in the lubricant. For example, lubricants often contain sulfurized additives, such as thiadiazole additives, to protect gears and other components from wear and galling. In many cases, a minimum amount of thiadiazole additive is included to achieve passable wear resistance with an acceptable failure load stage (FLS) in the FZG wear scar test according to CEC L-84-02 (A10 / 16.6R / 90C). However, although sulfurized additives may provide good load-bearing capabilities, sulfurized additives, particularly thiadiazole additives, may be detrimental to copper and copper alloys, resulting in unacceptable copper corrosion and poor performance in a modified ASTM D130-19 test (modified by extending the test at 150°C for 168 hours). Summary of the Invention

[0003] In one approach or embodiment, lubricating compositions suitable for use in vehicle transmissions are described herein. In one approach or embodiment, the lubricating compositions include one or more base oils of lubricating viscosity, at least about 0.35 weight percent of a thiadiazole additive, and one or more substituted trisarylphosphites having an overall ratio of para-substitution to ortho-substitution between 0.5 and 2.0. Preferably, the one or more trisarylphosphites include no meta-substitution.

[0004] In other approaches or embodiments, the lubricating composition may include one or more of the optional features or optional embodiments, in any combination. These optional features or embodiments may include one or more of the following:The para- and ortho-substitutions of the one or more triarylphosphites are independently C1 to C6 linear or branched hydrocarbyl groups, and / or the hydrocarbyl groups are selected from n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, or combinations thereof, and / or the one or more trisarylphosphites include or are tris(2,4-di-tert-butylphenyl)phosphite, and / or are tris(2,4-di-tert-butylphenyl)phosphite. and / or the one or more substituted trisarylphosphites have an overall ratio of para to ortho substitution between 0.8 and 1.2, or the one or more substituted trisarylphosphites have an overall ratio of para to ortho substitution between 0.9 and 1.0, or the one or more substituted trisarylphosphites have an overall ratio of para to ortho substitution of 1.0, and / or the lubricating composition exhibits a copper tarnish rating of 3B or less according to ASTM D130 after 168 hours at 150°C and contains 20 ppm or less copper leachate after testing according to ASTM D130 after 168 hours at 150°C, and / or exhibits a failure load stage of 7 or greater according to the FZG test of L-84-02 (A10 / 16.6R / 90C); and / or further comprises about 0.2 to about 0.6 weight percent of one or more substituted trisarylphosphites; and / or the thiadiazole additive is selected from monohydrocarbylthiol-substituted thiadiazoles, bishydrocarbylthiol-substituted thiadiazoles, or combinations thereof; and / or the thiadiazole additive comprises 2,5 dimercapto-1,3,4-thiadiazole; or 2,5 dimercapto-1,3,4-thiadiazole, and / or the 2,5 dimercapto-1,3,4-thiadiazole comprises 2,5-bis-(nonyldithio)-1,3,4-thiadiazole and 2,5-mono-(nonyldithio)-1,3,4-thiadiazole (preferably at about 10 to about 25%), and / or the lubricating composition comprises up to about 0.5 weight percent of the thiadiazole additive, and / or the thiadiazole additive comprises one or more compounds having the structure of Formula I:

[0005] [ka] wherein each R3 is independently hydrogen or sulfur, each R4 is independently an alkyl group, n is an integer of 0 or 1, and when R3 is hydrogen, the integer n of adjacent R4 moieties is 0, and when R3 is sulfur, the integer n of adjacent R4 moieties is 1, and at least one R3 is sulfur, and / or further comprises a sulfurized reaction product between a thiadiazole additive and one or more substituted trisarylphosphites, and / or the sulfurized reaction product is preferably a substituted sulfurized trisarylphosphite.

[0006] In another approach or embodiment, methods of lubricating a transmission are described herein. In each aspect, the method includes lubricating a transmission with a lubricating composition comprising one or more base oils of lubricating viscosity, at least about 0.35 weight percent of a thiadiazole additive, and one or more substituted trisarylphosphites having an overall ratio of para- to ortho-substitution between 0.5 and 2.0. Preferably, the one or more trisarylphosphites are free of meta-substitution.

[0007] In other approaches or embodiments, the methods herein may include optional features, steps, or embodiments in any combination. For example, these optional approaches or embodiments may include one or more of the following: the para- and ortho-substitutions of the one or more triarylphosphites are independently C1-C6 linear or branched hydrocarbyl groups, and / or the hydrocarbyl groups are selected from n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, or combinations thereof, and / or the one or more trisarylphosphites comprise tris(2,4-di-tert-butylphenyl)phosphite, and / or the lubricating composition exhibits a copper tarnish rating of 3B or less according to ASTM D130 after 168 hours at 150°C, contains no more than about 20 ppm copper leach after 168 hours at 150°C according to ASTM D130, and exhibits a failure load stage of 7 or greater according to the FZG test of CEC L-84-02 (A10 / 16.6R / 90C). In other embodiments, the methods herein may include any of the lubricating composition embodiments or approaches described above in the Summary of the Invention, in any combination.

[0008] In yet another embodiment or approach, the disclosure herein provides: Provided is the use of a lubricating composition comprising one or more base oils of lubricating viscosity, at least about 0.35 weight percent of a thiadiazole additive, and one or more substituted trisarylphosphites having an overall ratio of para- to ortho-substitution between 0.5 and 2.0, to achieve a copper tarnish rating of 3B or less according to ASTM D130 after 168 hours at 150°C, a copper leach of about 20 ppm or less after testing according to ASTM D130 after 168 hours at 150°C, and a failure load stage of 7 or greater according to the FZG test of CEC L-84-02 (A10 / 16.6R / 90C). The uses herein may include any of the embodiments of the lubricating compositions described in the Summary of the Invention.

[0009] Other embodiments of the present disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. The following definitions are provided to clarify the meaning of certain terms used herein.

[0010] The terms "gear oil," "gear fluid," "gear lubricant," "base gear lubricant," "lubricating oil," "lubricant composition," "lubricating composition," "lubricant," and "lubricating fluid" refer to a finished lubricating product comprising a major amount of a base oil and a minor amount of an additive composition, as discussed herein. Such gear fluids are intended for use in extreme pressure conditions, such as in transmissions (manual or automatic) and / or gear differentials, transmission and gear drive components having metal-to-metal contact.

[0011] As used herein, the term "hydrocarbyl substituent" or "hydrocarbyl group" is used in its ordinary sense, as is well known to those skilled in the art. Specifically, it refers to a group having a carbon atom directly attached to the remainder of the molecule and having a predominantly hydrocarbon character. Each hydrocarbyl group is independently selected from hydrocarbon substituents, where the substituted hydrocarbon substituents contain one or more of halo, hydroxyl, alkoxy, mercapto, nitro, nitroso, amino, pyridyl, furyl, imidazolyl, oxygen, and nitrogen, and no more than two non-hydrocarbon substituents are present for every 10 carbon atoms in the hydrocarbyl group.

[0012] As used herein, the terms "percent by weight" or "wt. %" or "weight percent" refer to the percentage of the listed component expressed relative to the weight of the entire composition, unless expressly stated otherwise. All percentages herein are weight percent unless otherwise specified. As used herein, "free" means that the functional amount of such component is less than about 0.1 weight percent, less than 0.05 weight percent, less than 0.01 weight percent, or none at all.

[0013] The terms "soluble," "oil-soluble," or "dispersible" used herein may, but do not necessarily, indicate that a compound or additive is soluble, dissolvable, miscible, or capable of being suspended in oil in any proportion. However, the terms do mean that they are, for example, soluble, suspendable, dissolvable, or stably dispersible in oil to a sufficient degree to exert their intended effect in the environment in which the oil is used. Furthermore, if desired, the incorporation of other additives may also allow for the incorporation of higher levels of the specific additive.

[0014] As used herein, the term "alkyl" refers to straight, branched, cyclic, and / or substituted saturated chain moieties of about 1 to about 200 carbon atoms. As used herein, the term "alkenyl" refers to straight, branched, cyclic, and / or substituted saturated chain moieties of about 3 to about 30 carbon atoms. As used herein, the term "aryl" refers to mono- and polycyclic aromatic compounds that may contain alkyl, alkenyl, alkylaryl, amino, hydroxyl, alkoxy, halo substituents, and / or heteroatoms such as, but not limited to, nitrogen and oxygen.

[0015] As used herein, molecular weight is measured by gel permeation chromatography (GPC) using commercially available polystyrene standards (with Mn of about 180 to about 18,000 as calibration standards). The molecular weight (Mn) of any embodiment herein may be determined using a gel permeation chromatography (GPC) instrument from Waters or similar instrumentation, and data processed with Waters Empower Software or similar software. The GPC instrument may be equipped with a Waters Separation Module and a Waters Refractive Index Detector (or similar optional instrumentation). GPC operating conditions may include a guard column, four Agilent PL gel columns (300 x 7.5 mm long, 5 μm particle size, and pore size range 100-10,000 Å), and a column temperature of about 40°C. Unstabilized HPLC-grade tetrahydrofuran (THF) may be used as the solvent at a flow rate of 1.0 mL / min. GPC instruments can be calibrated with commercially available polystyrene (PS) standards with narrow molecular weight distributions ranging from 500 to 380,000 g / mol. Calibration curves can be extrapolated for samples with masses less than 500 g / mol. Samples and PS standards can be dissolved in THF, prepared at concentrations of 0.1 to 0.5 weight percent, and used without filtration. GPC measurements are also described in U.S. Pat. No. 5,266,223, incorporated herein by reference. The GPC method also provides molecular weight distribution information. See, for example, W.W. Yau, J.J. Kirkland, and D.D. Bly, "Modern Size Exclusion Liquid Chromatography," John Wiley and Sons, New York, 1979, incorporated herein by reference.

[0016] Throughout this disclosure, the terms "comprises," "includes," "contains," and the like are intended to be open-ended and should be understood to include any element, step, or ingredient not expressly recited. The phrase "consisting essentially of" means including any explicitly recited element, step, or ingredient, as well as any additional elements, steps, or ingredients that do not materially affect the basic and novel aspects of the invention. This disclosure also contemplates that any composition described using the terms "comprises," "includes," or "contains" should be interpreted as including a disclosure of the same composition "consisting essentially of" or "consisting of" the specifically recited ingredient. DETAILED DESCRIPTION OF THE INVENTION

[0017] In one approach or embodiment, disclosed herein is a lubricating composition suitable as a transmission fluid (manual, automatic, or dual clutch), axle fluid, differential fluid, tractor fluid, industrial gear fluid, and / or lubricating fluid for other gear-type applications, having at least about 0.35 weight percent of a sulfurized antiwear additive, particularly at least about 0.3 weight percent of a thiadiazole additive. The lubricant also contains one or more substituted trisarylphosphites having a specific ratio of para- to ortho-alkylated substitution. 31 P-NMR can be used to determine the number of trisarylphosphite compounds in a lubricant, 13 C-NMR can be used to determine the number of ortho and para substituents on each phosphite compound. The inclusion of a combination of a thiadiazole additive and a selected phosphite in a lubricating composition enables the lubricating composition to achieve acceptable load-carrying capacity and copper corrosion performance.

[0018] Thiadiazole Additives

[0019] The lubricating compositions herein contain a minimum amount of thiadiazole additive, including one or more thiadiazole compounds or derivatives thereof, to achieve a passing failure load stage of 7 in the FZG test according to CEC L-84-02 (A10 / 16.6R / 90C). In each approach, the lubricating composition may contain about 0.3 weight percent or more of the thiadiazole additive. In other approaches, the lubricating composition may contain about 0.35 weight percent to about 1 weight percent, or about 0.35 weight percent to about 0.5 weight percent of the thiadiazole additive. In some approaches, the lubricating composition may contain about 0.4 weight percent of the thiadiazole additive. In some embodiments, the thiadiazole additive may be a mixture of thiadiazole compounds and / or hydrocarbyl-substituted derivatives thereof.

[0020] In some approaches, the thiadiazole additive provides at least about 1000 ppm of sulfur to the lubricating composition, and in other approaches, at least about 1200 ppm of sulfur, at least about 1400 ppm of sulfur, or at least about 1200 ppm to about 1500 ppm of sulfur, or at least about 1000 ppm to about 1500 ppm of sulfur, or at least about 1200 ppm to about 1500 ppm of sulfur.

[0021] In each approach, the thiadiazole additive or derivative thereof comprises one or more compounds having the structure of Formula I:

[0022] [ka] wherein each R3 is independently hydrogen or sulfur, each R4 is independently an alkyl group, and n is an integer of 0 or 1, and when R3 is hydrogen, the integer n of the adjacent R4 moiety is 0, and when R3 is sulfur, the integer n of the adjacent R4 moiety is 1, provided that at least one R3 is sulfur. In another approach, the thiadiazole additive is a blend of compounds of formula Ia and formula Ib, as shown below:

[0023] [ka] In Formula Ia, each integer n is 1, each R3 is sulfur, and each R4 is a C5-C 15 Alkyl groups, preferably C8 to C 12 is an alkyl group,

[0024] [ka] In formula Ib, one integer n is 1 and the associated R group is C5-C 15 Alkyl groups (preferably C8 to C 12 alkyl group), the associated R group is sulfur, and the other integer n is 0 and the associated R group is hydrogen. In some embodiments, the thiadiazole or derivative thereof comprises a blend of Formulas Ia and Ib, where Formula Ia is the majority of the blend; in other approaches, the blend of Ia and Ib is about 75 to about 90 weight percent Ia and about 10 to about 25 weight percent Ib (or other ranges therein). In another approach, the thiadiazole is a 2,5-dimercapto-1,3,4-thiadiazole, including a blend of 2,5-bis-(nonyldithio)-1,3,4-thiadiazole (e.g., about 75 to about 90%) and 2,5-mono-(nonyldithio)-1,3,4-thiadiazole (e.g., about 10 to about 25%).

[0025] In another approach or embodiment, examples of thiadiazole additives that may be used in the fluids herein include 2-mercapto-5-hydrocarbylthio-1,3,4-thiadiazole, 2-mercapto-5-hydrocarbyldithio-1,3,4-thiadiazole, 2,5-bis(hydrocarbylthio)-1,3,4-thiadiazole, 2,5-bis(hydrocarbyldithio)-1,3,4-thiadiazole, variations thereof, or combinations thereof. 1,3,4-Thiadiazoles are generally synthesized from hydrazine and carbon disulfide by known methods. See, for example, U.S. Patent Nos. 2,765,289, 2,749,311, 2,760,933, 2,850,453, 2,910,439, 3,663,561, 3,862,798, and 3,840,549, the disclosures of which are incorporated herein by reference.

[0026] Trisarylphosphite compounds

[0027] The lubricating compositions herein also include tris-arylphosphite compounds in which one or more of the aryl rings are disubstituted. The tris-arylphosphite compounds have a specific weight ratio of para- to ortho-substitution. Specifically, the tris-arylphosphite compounds have a weight ratio of para- to ortho-substitution of about 0.5 to about 2.0, or about 0.8 to about 1.5, or about 0.8 to about 1.2, or about 0.9 to about 1.1, or about 1.0. In other approaches, the tris-arylphosphite compounds are substantially free of meta-substituted alkyl groups (i.e., less than about 0.1 weight percent or less than about 0.05 weight percent of compounds having meta-substitution), or in other approaches, are free of tris-arylphosphite compounds having meta-substituted alkyl groups. As shown in the examples below, when lubricating compounds contain these selected ortho- and para-substituted phosphite compounds in combination with the above-described thiadiazole additives, the lubricants of the present invention achieve adequate FZG failure load stage performance and pass copper corrosion performance.

[0028] In one approach, a suitable disubstituted trisarylphosphite compound has the structure of Formula II:

[0029] [ka] wherein each of R5, R6, and / or R7 can independently be an alkylated aryl moiety such that the compound of Formula II has an overall ratio of para- to ortho-substitution of about 0.5 to about 2.0, or alternatively about 0.8 to about 1.5, or about 0.8 to about 1.2, or about 0.9 to about 1.1, or about 1.0. Each aryl group of the R5, R6, and R7 moieties is an aromatic moiety having 6 to 18 carbon atoms, such as a phenyl, naphthyl, phenanthryl, anthracyl, biphenyl, or terphenyl group; preferably, each aryl group of R5, R6, and R7 is a phenyl group. The aromatic groups R5, R6, and / or R7 may be disubstituted with two alkyl groups (so that the compound exhibits the above overall para-to-ortho ratio) and may optionally be further substituted with other substituents as required for a particular application, so long as any substitution does not substantially adversely affect the characteristics of the phosphite compound when combined with the thiadiazole additive herein. It is not necessary for each aromatic group R5, R6, and R7 to be disubstituted in the ortho and para positions. It is possible for one or more aromatic groups to be monosubstituted in either the ortho or para position, provided that the overall para-to-ortho substitution ratio satisfies the required ratio.

[0030] In some approaches, the alkyl substituents of the substituted aryl groups R5, R6, and / or R7 are straight or branched chain C1-C 10The alkyl groups may be selected from, for example, methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, or decyl groups, or combinations thereof. In another approach, the alkyl substitution includes a straight-chain or branched-chain alkyl group having 1 to 6 carbon atoms, preferably 4 to 6 carbon atoms. In yet another approach, each of the substituents on the aryl groups R5, R6, and R7 is a butyl group, more preferably a tert-butyl group. In one embodiment, the trisarylphosphite of the composition herein has the structure of Formula IIa.

[0031] [ka] wherein R8 and R9 may each independently be a linear or branched C1-C6 alkyl group or a linear or branched C4-C6 alkyl group, preferably R8 and R9 may each be a tert-butyl group, and the compound of formula IIa has a total weight ratio of para- to ortho-substitution of aromatic groups of about 0.5 to about 2.0, or in other approaches, about 0.8 to about 1.5, or about 0.8 to about 1.2, or about 0.9 to about 1.1, or about 1.0. In a preferred approach, the disubstituted trisarylphosphite of the composition herein may include tris(2,4-di-tert-butylphenyl)phosphite.

[0032] Disubstituted trisarylphosphite compounds can be prepared by a number of methods known to those skilled in the art. In one exemplary approach, such phosphite compounds can be prepared by alkylating a phenolic compound with an alkene, optionally in the presence of a suitable acid catalyst, and then reacting this mixture with a phosphorus halide (e.g., PZ3, where Z is a halogen). As used herein, it is understood by those skilled in the art that phenolic compounds include phenyl compounds (i.e., aromatic compounds having at least one OH group), optionally further substituted with groups that do not adversely affect their stabilizing properties when combined with thiadiazole additives. Thus, one exemplary method for preparing substituted trisarylphosphite compounds is by reacting a phosphorus trihalide, such as phosphorus trichloride or phosphorus tribromide, with a suitable alkylated phenol mixture. Triarylphosphites can also be prepared according to the method of Chinese Patent Publication No. 103224529, which is incorporated herein by reference.

[0033] In each approach, the lubricating compositions herein may contain about 0.2 weight percent or more of the tris-arylphosphite compound. In some approaches, the lubricating compositions may contain about 0.2 weight percent to about 0.6 weight percent, or about 0.3 weight percent to about 0.5 weight percent of the tris-arylphosphite compound. In one approach, the substituted tris-arylphosphite compound includes at least tris(2,4-di-tert-butylphenyl)phosphite having a para-substitution to ortho-substitution ratio as described above, or preferably a ratio of about 1.0. In another approach, the tris-arylphosphite compound herein may provide the lubricating composition with about 90 ppm to about 300 ppm of phosphorus, or about 100 ppm to about 250 ppm of phosphorus, or about 140 ppm to about 250 ppm of phosphorus, or about 200 ppm to 250 ppm of phosphorus.

[0034] Without wishing to be limited by theory, the combination of the thiadiazole additive and one or more substituted trisarylphosphite compounds herein may react to form products, such as sulfurized reaction products, that provide acceptable load-bearing capacity and improved copper corrosion performance. In some approaches, the thiadiazole additive and one or more substituted trisarylphosphite compounds form sulfurized trisarylphosphites. Such sulfurized reaction products may be formed when the fluid is exposed to temperatures of about 150°C or higher for extended periods of time.

[0035] In some approaches, the molar ratio of the thiadiazole additive to the substituted trisarylphosphite compound to help achieve improved copper corrosion in the lubricants herein may be from about 0.8:1 to about 1.3:1, or from about 0.9:1 to about 1.2:1, or from about 1.1:1 to about 1.2:1.

[0036] base oil

[0037] Suitable base oils for use in lubricating compositions according to the present disclosure may be mineral oils, animal oils, vegetable oils, synthetic oils, or mixtures thereof.

[0038] Natural oils may include animal and vegetable oils (e.g., castor oil, lard oil), as well as mineral oils, such as liquid petroleum oils and solvent- or acid-treated mineral lubricating oils of the paraffinic, naphthenic, or mixed paraffin-naphthenic types. Mineral oils may include oils obtained by drilling, or from plants and animals, or any mixture thereof. For example, such oils may include, but are not limited to, castor oil, lard oil, olive oil, peanut oil, corn oil, soybean oil, and linseed oil, as well as mineral lubricating oils, such as liquid petroleum oils and solvent- or acid-treated mineral lubricating oils of the paraffinic, naphthenic, or mixed paraffin-naphthenic types. Such oils may be partially or fully hydrogenated, if desired. Oils derived from coal or shale may also be suitable. Additionally, oils derived from gas-to-liquid processes are also suitable. The base oil may have a kinematic viscosity at 100° C. of about 2 to about 15 cSt as measured by ASTM D2270-10.

[0039] Useful synthetic lubricating oils may include hydrocarbon oils such as polymerized, oligomerized, or interpolymerized olefins (e.g., polybutylene, polypropylene, propylene-isobutylene copolymers); poly(1-hexene), poly(1-octene), trimers or oligomers of 1-decene, such as poly(1-decene) (such materials are often referred to as α-olefins), and mixtures thereof; alkyl-benzenes (e.g., dodecylbenzene, tetradecylbenzene, dinonylbenzene, di-(2-ethylhexyl)-benzene); polyphenyls (e.g., biphenyl, terphenyl, alkylated polyphenyls); diphenylalkanes, alkylated diphenylalkanes, alkylated diphenyl ethers, and alkylated diphenyl sulfides, as well as their derivatives, analogs, and homologs, or mixtures thereof. Polyalphaolefins are typically hydrogenated materials.

[0040] Other synthetic lubricating oils include polyol esters, diesters, liquid esters of phosphorus-containing acids (e.g., tricresyl phosphate, trioctyl phosphate, and diethyl ester of decane phosphonic acid), or polymeric tetrahydrofurans. Synthetic oils can be produced by the Fischer-Tropsch reaction and are typically hydroisomerized Fischer-Tropsch hydrocarbons or waxes. In one embodiment, the oils can be prepared by the Fischer-Tropsch gas-to-liquid synthesis procedure, as well as other gas-to-liquid oils.

[0041] The base oil or base oil of lubricating viscosity used in the compositions herein can be a single base oil or a mixture of two or more base oils. One or more base oils can be selected from any of Groups I to V of the base oils designated in the American Petroleum Institute (API) Base Oil Interchangeability Guidelines. These base oil groups are as follows:

[0042] [Table 1]

[0043] Group I, Group II, and Group III are mineral oil process feedstocks. Group IV base oils contain synthetic molecular species produced by the polymerization of olefinically unsaturated hydrocarbons. API Group IV base oils, polyalphaolefins (PAOs), are typically derived from monomers having 4 to 30, 4 to 20, or 6 to 16 carbon atoms. Examples of PAOs that can be used in the present invention include those derived from octene, decene, and mixtures thereof. PAOs can have kinematic viscosities of 2 to 15, 3 to 12, or 4 to 8 cSt at 100°C, as measured by ASTM D2270-10. Examples of suitable PAO viscosities include 4 cSt at 100°C, 6 cSt at 100°C, and both. Many Group V base oils are also truly synthetic and can include diesters, polyol esters, polyalkylene glycols, alkylated aromatics, polyphosphate esters, polyvinyl ethers, and / or polyphenyl ethers, but can also be natural oils, such as vegetable oils. It should be noted that although Group III base oils are derived from mineral oils, the rigorous processing these fluids undergo makes their physical properties very similar to some true synthetic oils. Thus, oils derived from Group III base oils may be referred to in the industry as synthetic fluids. Suitable oils may be derived from hydrocracked, hydrogenated, hydrofinished, unrefined, refined, and rerefined oils, as well as mixtures thereof.

[0044] Unrefined oils are derived from natural, mineral, or synthetic sources with little or no further purification processing. Refined oils are similar to unrefined oils except that they have been treated with one or more purification steps, which may result in the improvement of one or more properties. Examples of suitable purification techniques include solvent extraction, secondary distillation, acid or base extraction, filtration, percolation, etc. Oils refined to edible quality may or may not be useful. Edible oils may also be called white oils. In some embodiments, the lubricating oil composition does not include edible oils or white oils.

[0045] Re-refined oils are also known as reclaimed or reprocessed oils. These oils are obtained using the same or similar processes as refined oils. Often, these oils are further processed by techniques directed to the removal of spent additives and oil breakdown products.

[0046] The base oil, in combination with the additive composition as disclosed in embodiments herein, provides a lubricating fluid for a transmission, axle, tractor, or industrial gear. Thus, the base oil may be present in the lubricating fluid in an amount greater than about 80 wt. % based on the total weight of the lubricating fluid. In some embodiments, the base oil may be present in the lubricating fluid in an amount greater than about 85 wt. % based on the total weight of the lubricating fluid, and may be selected from any suitable synthetic or natural oil, or mixtures thereof, having a suitable lubricating viscosity.

[0047] Suitable transmission, axle, differential, tractor, or industrial gear lubricant compositions herein may contain additive components in the ranges listed in Table 2 below.

[0048] [Table 2]

[0049] The percentages of each component above represent the weight percent of each component based on the weight of the total lubricating oil composition. The remainder of the lubricating oil composition consists of one or more base oils. The additives used in formulating the compositions described herein can be blended into the base oil individually or in various partial combinations. However, it may be preferred to blend all of the components simultaneously using an additive concentrate (i.e., additives plus a diluent such as a hydrocarbon solvent).

[0050] The lubricating compositions described herein can be formulated to provide lubrication, adequate load-bearing capacity, and improved copper corrosion resistance for various applications. The lubricating fluids disclosed herein can be used in transmission fluids, axle fluids, differential fluids, tractor fluids, industrial gear fluids, and stationary gearboxes. Gear types include, but are not limited to, spur, spiral, worm, rack and pinion, involute, bevel, helical, planetary, and hypoid gears, as well as limited-slip applications and differentials. The driveline lubricating compositions disclosed herein are also suitable for automatic or manual transmissions, including stepped automatic transmissions, continuously variable transmissions, semi-automatic transmissions, automated manual transmissions, toroidal transmissions, and dual-clutch transmissions. The driveline lubricating compositions disclosed herein are particularly suitable for use in axles, transfer cases, and differentials, such as linear differentials, rotating differentials, limited-slip differentials, clutch-type differentials, and locking differentials.

[0051] Optional Additives

[0052] In another approach, lubricants containing such additives as described above may also contain one or more optional ingredients, as long as such ingredients and their amounts do not affect the performance characteristics as described in the preceding paragraphs. These optional ingredients are described in the following paragraphs.

[0053] Other phosphorus-containing compounds

[0054] The lubricant compositions herein may contain one or more phosphorus-containing compounds, which may impart antiwear benefits to the fluid. The one or more phosphorus-containing compounds may be present in the lubricant composition in an amount ranging from about 0 wt. % to about 5 wt. %, or from about 0.01 wt. % to about 4 wt. %, or from about 0.05 wt. % to about 3 wt. %, or from about 0.1 wt. % to about 3 wt. % of the lubricant composition. The phosphorus-containing compounds may provide the lubricant composition with up to 500 ppm phosphorus, or from about 3 to about 100 ppm phosphorus, or from about 4 to about 20 ppm phosphorus, or up to 50 ppm phosphorus, or up to 20 ppm phosphorus.

[0055] The one or more phosphorus-containing compounds may comprise ashless phosphorus-containing compounds.Suitable examples of phosphorus-containing compounds include, but are not limited to, thiophosphates, dithiophosphates, phosphates, phosphoric acid esters, phosphate esters, phosphites, phosphonates, phosphorus-containing carboxylic acid esters, ethers, or amide salts thereof, and mixtures thereof.Phosphorus-containing antiwear agents are more fully described in EP 0612839.

[0056] It should be noted that the terms phosphonate and phosphite are often used interchangeably in the lubricant industry. For example, dibutyl hydrogen phosphonate is sometimes referred to as dibutyl hydrogen phosphite. It is within the scope of the present invention that the lubricant compositions of the present invention include phosphorus-containing compounds that may be referred to as either phosphites or phosphonates.

[0057] In any of the above phosphorus-containing compounds, the compound can have from about 4 to about 8 weight percent phosphorus, or from about 5 to about 6 weight percent phosphorus.

[0058] In some embodiments, the ashless phosphorus-containing compound can be a dialkyldithiophosphate ester, amyl acid phosphate, diamyl acid phosphate, dibutyl hydrogen phosphate, dimethyloctadecyl phosphate, salts thereof, and mixtures thereof.

[0059] The ashless phosphorus-containing compound has the formula:

[0060] [ka] and wherein R1 is S or O, R2 is -OR, -OH, or -R", R3 is -OR", -OH, or -SR'"C(O)OH, R4 is -OR", R'" is a C1-C3 branched or linear alkyl chain, and R" is a C1-C3 alkyl group. 18 is a hydrocarbyl chain. When the phosphorus-containing compound has the structure shown in Formula XIV, the compound can have from about 8 weight percent to about 16 weight percent phosphorus.

[0061] In some embodiments, the lubricating composition comprises a phosphorus-containing compound of Formula XIV, wherein R is O, R is H, and R and R are each OR″, where R″ is C 18 and the phosphorus-containing compound is present in an amount to provide the lubricating composition with 3 to 50 ppm phosphorus or 3 to 20 ppm phosphorus. In other embodiments, the lubricating composition comprises a phosphorus-containing compound of Formula XIV, where R1 is O, R2 is H, and R3 and R4 are each OR″, where R″ is oleyl, and the phosphorus-containing compound is present in an amount to provide the lubricating composition with 3 to 50 ppm phosphorus or 3 to 20 ppm phosphorus.

[0062] In some embodiments, the lubricant composition comprises a phosphorus-containing compound of Formula XIV, where R1 is S, R2 is —OR″, R3 is SR′″COOH, R4 is —OR″, R′″ is a C3 branched alkyl chain, and R″ is C4, and the phosphorus-containing compound is present in an amount providing 3 to 50 ppm of phosphorus to the lubricant composition.

[0063] In another embodiment, the lubricant composition includes a phosphorus-containing compound of Formula XIV, where R1 is O, R2 is —OH, R3 is —OR″ or —OH, R4 is —OR″, and R″ is C5, and the phosphorus-containing compound is present in an amount providing 3 to 50 ppm phosphorus to the lubricant composition.

[0064] In yet another embodiment, the lubricant composition includes phosphorus-containing compounds of Formula XIV, where R1 is O, R2 is OR", R3 is H, R4 is —OR″, and R″ is C4, and the one or more phosphorus-containing compounds are present in an amount providing 3 to 50 ppm phosphorus to the lubricant composition.

[0065] In another embodiment, the lubricant composition comprises a phosphorus-containing compound of Formula XIV, where R1 is O, R2 is —R″, R3 is —OCH3 or —OH, R4 is —OCH3, and R″ is C 18 and the one or more phosphorus-containing compounds are present in an amount to provide 3 to 50 ppm of phosphorus to the lubricant composition.

[0066] Other anti-wear agents

[0067] The lubricant composition may also contain other antiwear agents that are phosphorus-free compounds. Examples of such antiwear agents include boric acid esters, boric acid epoxides, thiocarbamate compounds (e.g., thiocarbamate esters, alkylene-bonded thiocarbamates, and bis(S-alkyldithiocarbamyl)disulfides, thiocarbamate amides, thiocarbamic acid ethers, alkylene-bonded thiocarbamates, and bis(S-alkyldithiocarbamyl)disulfides, and mixtures thereof), sulfurized olefins, tridecyl adipate, titanium compounds, and long-chain derivatives of hydroxylcarboxylic acids, such as tartrate derivatives, tartramide, tartrimide, citrate, and mixtures thereof. A suitable thiocarbamate compound is molybdenum dithiocarbamate. A suitable tartrate derivative or tartrimide may contain an alkyl-ester group, where the total number of carbon atoms on the alkyl group may be at least 8. The tartrate derivatives or tartrimides may contain alkyl-ester groups, where the total number of carbon atoms on the alkyl group may be at least 8. The antiwear agent may, in one embodiment, include citrate. The additional antiwear agent may be present in a range including from about 0% to about 5% by weight of the lubricating oil composition, or from about 0.01% to about 4% by weight, or from about 0.05% to about 3% by weight, or from about 0.1% to about 3% by weight.

[0068] Other sulfur-containing compounds

[0069] The lubricant compositions of this disclosure may also contain other sulfur-containing compounds that provide for extreme pressure performance, so long as the lubricating compositions herein contain the described amounts and profiles described herein. A wide variety of sulfur-containing extreme pressure agents are suitable, including 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 (e.g., U.S. Pat. Nos. 2,995,569, 3,673,090, 3,703,504, 3,703,505, 3,796,661, 3,873,454, 4,119,549, 4,119,550, 4,147,640, 4,191,659, 4,240,958, 4,344,854, 4,472,306, and 4, 711,736), dihydrocarbyl polysulfides (see, e.g., U.S. Pat. Nos. 2,237,625, 2,237,627, 2,527,948, 2,695,316, 3,022,351, 3,308,166, 3,392,201, 4,564,709, and British Patent No. 1,162,334), functionally substituted dihydrocarbyl polysulfides (see, e.g., U.S. Pat. No. 4,218,332), and polysulfide olefin products (see, e.g., U.S. Pat. No. 4,795,576).

[0070] One suitable class of extreme pressure agents is represented by the formula: Ra-S xPolysulfides comprised of one or more compounds represented by —Rb, where R and Rb are hydrocarbyl groups, each of which may contain 1 to 18 carbon atoms, or in other approaches, 3 to 18 carbon atoms; x may be 2 to 8, typically 2 to 5, and especially 3. In some approaches, x is an integer from 3 to 5, with about 30 to about 60 percent of the x's being the integer 3 or 4. The hydrocarbyl groups may be of various types, such as alkyl, cycloalkyl, alkenyl, aryl, or aralkyl. Tertiary alkyl polysulfides, such as di-tert-butyl trisulfide, and mixtures containing di-tert-butyl trisulfide (e.g., mixtures composed primarily or entirely of tri-, tetra-, and pentasulfides) can be used. Other useful dihydrocarbyl polysulfides include diamyl polysulfide, dinonyl polysulfide, didodecyl polysulfide, and dibenzyl polysulfide.

[0071] Another suitable class of extreme pressure agents is sulfurized isobutene, which is made by reacting an olefin, such as isobutene, with sulfur. Sulfurized isobutene (SIB), particularly sulfurized polyisobutylene, typically has a sulfur content of about 10 to about 55% by weight, desirably about 30 to about 50% by weight. A wide variety of other olefins or unsaturated hydrocarbons, such as isobutene dimer or trimer, can be used to form sulfurized olefin extreme pressure agents. Various methods for preparing sulfurized olefins have been disclosed in the prior art. See, for example, U.S. Pat. No. 3,471,404 to Myers, U.S. Pat. No. 4,204,969 to Papay et al., U.S. Pat. No. 4,954,274 to Zaweski et al., U.S. Pat. No. 4,966,720 to DeGonia et al., and U.S. Pat. No. 3,703,504 to Horodysky et al., each of which is incorporated herein by reference.

[0072] Methods for preparing sulfurized olefins, including those disclosed in the aforementioned patents, involve the formation of a material typically referred to as an "adduct," in which an olefin is reacted with a sulfur halide, such as sulfur monochloride. The adduct is then reacted with a sulfur source to provide the sulfurized olefin. The quality of the sulfurized olefin is generally measured by various physical properties, such as viscosity, sulfur content, halogen content, and copper corrosion test weight loss. U.S. Pat. No. 4,966,720 relates to sulfurized olefins useful as extreme pressure additives in lubricating oils and a two-step reaction for their preparation.

[0073] In some embodiments, the extreme pressure agent is present in the lubricating composition in an amount of up to about 3.0 wt % or up to about 5.0 wt %. In other embodiments, the extreme pressure agent is present in an amount of from about 0.05 wt % to about 0.5 wt %, based on the total weight of the lubricating composition. In other embodiments, the extreme pressure agent is present in an amount of from about 0.1 wt % to about 3.0 wt %, based on the total weight of the lubricating composition. In other embodiments, the extreme pressure agent is present in an amount of from about 0.6 wt % to about 1 wt %, based on the total weight of the lubricating composition.

[0074] antioxidants

[0075] The lubricating oil compositions herein may also optionally contain one or more antioxidants. Antioxidant compounds are known and include, for example, phenates, phenate sulfides, sulfurized olefins, phosphosulfurized terpenes, sulfurized esters, aromatic amines, alkylated diphenylamines (e.g., nonyldiphenylamine, di-nonyldiphenylamine, octyldiphenylamine, di-octyldiphenylamine), phenyl-alpha-naphthylamines, alkylated phenyl-alpha-naphthylamines, hindered non-aromatic amines, phenols, hindered phenols, oil-soluble molybdenum compounds, polymeric antioxidants, or mixtures thereof. The antioxidant compounds may be used alone or in combination.

[0076] The hindered phenol antioxidant may contain a secondary butyl group and / or a tertiary butyl group as a steric hindering group. The phenol group may be further substituted with a hydrocarbyl group and / or a bridging group connecting to a second aromatic group. Examples of suitable hindered phenol antioxidants include 2,6-di-tert-butylphenol, 4-methyl-2,6-di-tert-butylphenol, 4-ethyl-2,6-di-tert-butylphenol, 4-propyl-2,6-di-tert-butylphenol, 4-butyl-2,6-di-tert-butylphenol, or 4-dodecyl-2,6-di-tert-butylphenol. In one embodiment, the hindered phenol antioxidant can be an ester and can include, for example, Irganox® L-135 available from BASF or an addition product derived from 2,6-di-tert-butylphenol and an alkyl acrylate, where the alkyl group can contain from about 1 to about 18, or from about 2 to about 12, or from about 2 to about 8, or from about 2 to about 6, or about 4 carbon atoms. Another commercially available hindered phenol antioxidant can be an ester and can include Ethanox® 4716 available from Albemarle Corporation.

[0077] One particularly useful antioxidant includes nonyldiphenylamine and dinonyldiphenylamine. In one embodiment, the lubricating oil composition may contain one or more of these diphenylamines present in an amount up to about 1 wt %.

[0078] The one or more antioxidants may be present in the range of about 0% to about 3%, or about 0.1% to about 1%, or about 0.1% to about 0.5% by weight of the lubricating oil composition.

[0079] Dispersants

[0080] Lubricant compositions may contain one or more selective dispersants or mixtures thereof. Dispersants are often known as ashless dispersants because they do not contain ash-forming metals prior to incorporation into the lubricating oil composition and do not typically contribute any ash when added to the lubricant. Ashless dispersants are characterized by a polar group attached to a relatively high molecular weight hydrocarbon chain. Typical ashless dispersants include N-substituted long-chain alkenyl succinimides. N-substituted long-chain alkenyl succinimides contain polyisobutylene (PIB) substituents with a number average molecular weight of the polyisobutylene substituent ranging from about 800 to about 2500, as determined by gel permeation chromatography (GPC) using polystyrene (having a number average molecular weight of 180 to about 18,000) as the calibration standard. PIB substituents used in dispersants typically have a viscosity of about 2100 to about 2700 cSt at 100°C, as determined using ASTM D445-18. Succinimide dispersants and their preparation methods are disclosed, for example, in U.S. Patent Nos. 7,897,696 and 4,234,435, which are incorporated herein by reference. Succinimide dispersants are typically imides formed from polyamines, typically poly(ethyleneamines). The dispersant may contain two succinimide moieties connected by a polyamine. The polyamine may be tetraethylenepentamine (TEPA), triethylenetetraamine (TETA), pentaethylenehexamine (PEHA), other higher nitrogen ethylenediamine species, and / or mixtures thereof. The polyamine may be a mixture of linear, branched, and cyclic amines. A PIB substituent may be attached to each succinimide moiety.

[0081] In some embodiments, the lubricant composition comprises at least one polyisobutylene succinimide dispersant derived from polyisobutylene having a number average molecular weight, as measured by the GPC method described above, in the range of from about 350 to about 5000, or from about 500 to about 3000. The polyisobutylene succinimide may be used alone or in combination with other dispersants.

[0082] In some embodiments, PIB, when present, may have a terminal double bond content of greater than 50 mol%, greater than 60 mol%, greater than 70 mol%, greater than 80 mol%, or greater than 90 mol%. Such PIB is also referred to as highly reactive PIB ("HR-PIB"). HR-PIB having a number average molecular weight in the range of about 800 to about 5000 is suitable for use in embodiments of the present disclosure. Conventional non-highly reactive PIBs typically have a terminal double bond content of less than 50 mol%, less than 40 mol%, less than 30 mol%, less than 20 mol%, or less than 10 mol%.

[0083] HR-PIB having a number average molecular weight ranging from about 900 to about 3000, as measured by the GPC method described above, may be suitable. Such HR-PIB is commercially available or can be synthesized by polymerization of isobutene in the presence of a non-chlorinated catalyst, such as boron trifluoride, as described in U.S. Pat. Nos. 4,152,499 and 5,739,355. When used in the aforementioned thermal ene reaction, HR-PIB can result in higher conversion rates and less precipitate formation in the reaction due to its increased reactivity.

[0084] In some embodiments, the lubricant composition includes at least one dispersant derived from polyisobutylene succinic anhydride. In some embodiments, the dispersant may be derived from polyalphaolefin (PAO) succinic anhydride.

[0085] One class of suitable dispersants can be Mannich bases. Mannich bases are materials formed by the condensation of higher molecular weight alkyl-substituted phenols, polyalkylene polyamines, and aldehydes such as formaldehyde. Mannich bases are described in more detail in U.S. Pat. No. 3,634,515.

[0086] A suitable class of dispersants may also be high molecular weight esters or half ester amides.

[0087] Dispersants can also be post-treated by conventional methods by reaction with any of a variety of agents, including boron, urea, thiourea, dimercaptothiadiazoles, carbon disulfide, aldehydes, ketones, carboxylic acids, hydrocarbon-substituted succinic anhydrides, maleic anhydride, nitriles, epoxides, carbonates, cyclic carbonates, hindered phenol esters, and phosphorus compounds. U.S. Patent Nos. 7,645,726, 7,214,649, and 8,048,831 describe some suitable post-treatment methods and products.

[0088] Suitable boron compounds useful in forming the dispersants herein include any boron compound or mixture of boron compounds capable of introducing a boron-containing species into the ashless dispersant. Any organic or inorganic boron compound capable of undergoing such a reaction can be used. Thus, boron oxide, boron oxide hydrate, boron trifluoride, boron tribromide, boron trichloride, HBF4, boric acids such as boronic acids (e.g., alkyl-B(OH)2 or aryl-B(OH)2), boric acid (i.e., H3BO3), tetraboric acid (i.e., H2BO7), metaboric acid (i.e., HBO2), ammonium salts of such boric acids, and esters of such boric acids can be used. The use of complexes of boron trihalides with ethers, organic acids, inorganic acids, or hydrocarbons is a convenient means of introducing the boron reactant into the reaction mixture. Such complexes are known and are exemplified by boron trifluoride-diethyl ether, boron trifluoride-phenol, boron trifluoride-phosphoric acid, boron trichloride-chloroacetic acid, boron tribromide-dioxane, and boron trifluoride-methyl ethyl ether.

[0089] Suitable phosphorus compounds for forming the dispersants herein include any phosphorus compound or mixture of phosphorus compounds capable of introducing phosphorus-containing species into the ashless dispersant. Therefore, any organic or inorganic phosphorus compound capable of undergoing such a reaction can be used. Accordingly, such inorganic phosphorus compounds can be used as inorganic phosphorus oxides, including inorganic phosphoric acid and its hydrates. Typical organophosphorus compounds include full and partial esters of phosphoric acid, such as mono-, di-, and triesters of phosphoric, thiophosphoric, dithiophosphoric, trithiophosphoric, and tetrathiophosphoric acids; mono-, di-, and triesters of phosphorous, thiophosphorous, and thiophosphorous acids; dithiophosphorous and trithiophosphorous acids; trihydrocarbyl phosphine oxides; trihydrocarbyl phosphine sulfides; mono- and dihydrocarbyl phosphonates (RPO(OR')(OR"), where R and R' are hydrocarbyl and R" is hydrogen or a hydrocarbyl group), and their mono-, di-, and trithio analogs; mono- and dihydrocarbyl phosphonites (RP(OR')(OR"), where R and R' are hydrocarbyl and R" is hydrogen or a hydrocarbyl group), and their mono- and dithio analogs. Thus, such compounds may be, for example, phosphorous acid (H3PO3, sometimes represented as H2(HPO3) and sometimes called ortho-phosphorous acid or phosphonic acid), phosphoric acid (H3PO4, sometimes called orthophosphoric acid), hypophosphoric acid (H4P2O6), metaphosphoric acid (HPO3), pyrophosphoric acid (H4P2O7), hypophosphorous acid (H3PO2, sometimes called phosphinic acid), pyrophosphorous acid (H4P2O5, sometimes called pyrophosphonic acid), phosphinous acid (H3PO), tripolyphosphoric acid (H5P3O 10 ), tetrapolyphosphate (H5P4O 13 ), trimetaphosphoric acid (H3P3O9), phosphorus trioxide, phosphorus tetroxide, phosphorus pentoxide, etc. Phosphorotetrathioic acid (H3PS4), phosphoromonothioic acid (H3PO3S), phosphorodithioic acid (H3PO2S2), phosphorotrithioic acid (H3POS3), phosphorus sesquisulfide, phosphorus heptasulfide, and phosphorus pentasulfide (PS5, P4S10 Partial or all sulfur analogs such as HCl, HCl (sometimes referred to as HCl), may also be used in forming dispersants for the present disclosure. Inorganic phosphorus halide compounds such as PCl, PBr, POCl, PSCl, etc. may also be used.

[0090] Similarly, such organophosphorus compounds may be used as mono-, di-, and triesters of phosphoric acid (e.g., trihydrocarbyl phosphates, dihydrocarbyl monoacid phosphates, monohydrocarbyl diacid phosphates, and mixtures thereof), mono-, di-, and triesters of phosphorous acid (e.g., trihydrocarbyl phosphites, dihydrocarbyl hydrogen phosphites, hydrocarbyl diacid phosphites, and mixtures thereof), esters of phosphonic acid (both "primary", R P(O)(OR) and "secondary", R P(O)(OR)), esters of phosphinic acid, phosphonyl halides (e.g., For example, RP(O)Cl and RP(O)Cl), halophosphites (e.g., (RO)PCl and (RO)PCl), halophosphates (e.g., ROP(O)Cl and (RO)P(O)Cl), tertiary pyrophosphates (e.g., (RO)P(O)-OP(O)(OR)), and all- or partial-sulfur analogs of any of the foregoing organophosphorus compounds can be used, where each hydrocarbyl group contains up to about 100 carbon atoms, or up to about 50 carbon atoms, or up to about 24 carbon atoms, or up to about 12 carbon atoms. Halophosphines (e.g., hydrocarbyl phosphorus tetrahalides, dihydrocarbyl phosphorus trihalides, and trihydrocarbyl phosphorus dihalides), and halophosphines (monohalophosphines and dihalophosphines) can also be used.

[0091] Lubricants herein may include mixtures of one or more of the borated and phosphated dispersants described above in combination with non-boronated and non-phosphated dispersants.

[0092] In one embodiment, the lubricating oil composition may contain at least one borated dispersant, wherein the dispersant is a reaction product of an olefin copolymer or a reaction product of an olefin copolymer with succinic anhydride and at least one polyamine. The ratio of PIBSA to polyamine may be from 1:1 to 10:1, or from 1:1 to 5:1, or from 4:3 to 3:1, or from 4:3 to 2:1. Particularly useful dispersants comprise polyisobutenyl groups of PIBSA having a number average molecular weight (Mn) in the range of about 500 to 5000 as measured by the GPC method described above, and a polyisobutenyl group of the general formula HN(CH). m -[NH(CH2) m ] n and (B) a polyamine having —NH 2 , wherein m is in the range of 2 to 4 and n is in the range of 1 to 2.

[0093] In addition to the above, the dispersant may be post-treated with an aromatic carboxylic acid, aromatic polycarboxylic acid, or aromatic anhydride, with all carboxylic acid or anhydride groups directly attached to the aromatic ring. Such carboxyl-containing aromatic compounds may be selected from 1,8-naphthalene acid or anhydride and 1,2-naphthalenedicarboxylic acid or anhydride, 2,3-naphthalenedicarboxylic acid or anhydride, naphthalene-1,4-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, phthalic anhydride, pyromellitic anhydride, 1,2,4-benzenetricarboxylic anhydride, diphenic acid or anhydride, 2,3-pyridinedicarboxylic acid or anhydride, 3,4-pyridinedicarboxylic acid or anhydride, 1,4,5,8-naphthalenetetracarboxylic acid or anhydride, perylene-3,4,9,10-tetracarboxylic anhydride, pyrenedicarboxylic acid or anhydride, and the like. The moles of this post-treatment component reacted per mole of polyamine may range from about 0.1:1 to about 2:1. Typical molar ratios of this post-treatment component to polyamine in the reaction mixture may range from about 0.2:1 to about 2:1. Alternative molar ratios of this post-treatment component to polyamine that may be used may range from 0.25:1 to about 1.5:1. This post-treatment component may be reacted with the other components at temperatures ranging from about 140°C to about 180°C.

[0094] Alternatively, or in addition to the above-mentioned post-treatment, the dispersant may be post-treated with a non-aromatic dicarboxylic acid or anhydride. The non-aromatic dicarboxylic acid or anhydride may have a number average molecular weight of less than 500 as measured by the GPC method described above. Suitable carboxylic acids or anhydrides may include, but are not limited to, acetic acid or anhydride, oxalic acid and anhydride, malonic acid and anhydride, succinic acid and anhydride, alkenylsuccinic acid and anhydride, glutaric acid and anhydride, adipic acid and anhydride, pimelic acid and anhydride, suberic acid and anhydride, azelaic acid and anhydride, sebacic acid and anhydride, maleic acid and anhydride, fumaric acid and anhydride, tartaric acid and anhydride, glycolic acid and anhydride, 1,2,3,6-tetrahydronaphthalic acid and anhydride, and the like.

[0095] The non-aromatic carboxylic acid or anhydride is reacted with the polyamine in a molar ratio ranging from about 0.1 to about 2.5 moles per mole of polyamine. Typically, the amount of non-aromatic carboxylic acid or anhydride used will be proportional to the number of secondary amino groups in the polyamine. Thus, about 0.2 to about 2.0 moles of non-aromatic carboxylic acid or anhydride per secondary amino group in component B can be reacted with the other components to provide a dispersant according to an embodiment of the present disclosure. Other molar ratios of non-aromatic carboxylic acid or anhydride to polyamine that can be used range from 0.25:1 to about 1.5:1 moles per mole of polyamine. The non-aromatic carboxylic acid or anhydride can be reacted with the other components at temperatures ranging from about 140°C to about 180°C.

[0096] The weight percent actives of the alkenyl or alkyl succinic anhydride can be measured using chromatographic techniques. This method is described in columns 5 and 6 of U.S. Patent No. 5,334,321. The polyolefin conversion is calculated from the actives percent using the formula in columns 5 and 6 of U.S. Patent No. 5,334,321.

[0097] Suitable borated dispersants may have a TBN of from about 10 to about 65 mg KOH / gram without oil, which is equivalent to a TBN of from about 5 to about 30 mg KOH / gram when measured on a dispersant sample containing about 50% diluent oil.

[0098] Typically, the dispersants described above are provided in the lubricant at about 4.5 to about 10 weight percent, and in other approaches, about 4.5 to about 8 weight percent, and in yet other approaches, about 4.5 to about 7.7 weight percent.

[0099] Viscosity Index Improver

[0100] The lubricant compositions herein may also optionally contain one or more viscosity index improvers. Suitable viscosity index improvers may include polyolefins, olefin copolymers, ethylene / propylene copolymers, polyisobutene, hydrogenated styrene-isoprene polymers, styrene / maleic acid ester copolymers, hydrogenated styrene / butadiene copolymers, hydrogenated isoprene polymers, alpha-olefin maleic anhydride copolymers, polymethacrylates, polyacrylates, polyalkylstyrenes, hydrogenated alkenylaryl conjugated diene copolymers, or mixtures thereof. The viscosity index improver may include star polymers; suitable examples are described in U.S. Patent Application Publication No. 2012 / 0101017(A1), which is incorporated herein by reference.

[0101] The lubricating oil compositions herein may also optionally contain one or more dispersant viscosity index improvers in addition to or in place of a viscosity index improver. Suitable viscosity index improvers may include functionalized polyolefins, such as ethylene-propylene copolymers functionalized with the reaction product of an acylating agent (such as maleic anhydride) and an amine, amine-functionalized polymethacrylates, or esterified maleic anhydride-styrene copolymers reacted with amines.

[0102] The total amount of viscosity index improver and / or dispersant viscosity index improver can be from about 0% to about 10%, from about 0.1% to about 8%, or from about 0.1% to about 6% by weight of the lubricating oil composition.

[0103] In some embodiments, the viscosity index improver is a polyolefin or olefin copolymer having a number average molecular weight of about 10,000 to about 500,000, about 50,000 to about 200,000, or about 50,000 to about 150,000. In some embodiments, the viscosity index improver is a hydrogenated styrene / butadiene copolymer having a number average molecular weight of about 40,000 to about 500,000, about 50,000 to about 200,000, or about 50,000 to about 150,000. In some embodiments, the viscosity index improver is a polymethacrylate having a number average molecular weight of about 10,000 to about 500,000, about 50,000 to about 200,000, or about 50,000 to about 150,000.

[0104] Other optional additives

[0105] The other additives can be selected to perform one or more functions required of the lubricant composition. Furthermore, one or more of the aforementioned additives may be multifunctional and may provide functions in addition to or other than those described herein. The other additives may be in addition to those specified in this disclosure and / or may include one or more of metal deactivators, viscosity index improvers, ashless TBN boosters, antiwear agents, corrosion inhibitors, rust inhibitors, dispersants, dispersant viscosity index improvers, extreme pressure agents, antioxidants, foam suppressants, demulsifiers, emulsifiers, pour point depressants, seal swell agents, and mixtures thereof. Typically, fully formulated lubricating oils contain one or more of these additives.

[0106] Suitable metal deactivators may include derivatives of benzotriazole (typically tolyltriazole), dimercaptothiadiazole derivatives, 1,2,4-triazole, benzimidazole, 2-alkyldithiobenzimidazole, or 2-alkyldithiobenzothiazole; foam suppressors including copolymers of ethyl acrylate, 2-ethylhexyl acrylate, and optionally vinyl acetate; demulsifiers including trialkyl phosphate, polyethylene glycol, polyethylene oxide, polypropylene oxide, and (ethylene oxide-propylene oxide) polymers; pour point depressants including esters of maleic anhydride-styrene, polymethacrylate, polyacrylate, or polyacrylamide.

[0107] Suitable suds suppressors include silicon-based compounds such as siloxanes.

[0108] Suitable pour point depressants may include polymethyl methacrylate or mixtures thereof. The pour point depressant may be present in an amount sufficient to provide from about 0 wt % to about 1 wt %, from about 0.01 wt % to about 0.5 wt %, or from about 0.02 wt % to about 0.04 wt %, based on the final weight of the lubricating oil composition.

[0109] Suitable rust inhibitors can be a single compound or a mixture of compounds that have the property of inhibiting corrosion of ferrous metal surfaces. Non-limiting examples of rust inhibitors useful herein include oil-soluble high molecular weight organic acids such as 2-ethylhexanoic acid, lauric acid, myristic acid, palmitic acid, oleic acid, linoleic acid, linolenic acid, behenic acid, and cerotic acid, as well as oil-soluble polycarboxylic acids, including dimer and trimer acids such as those produced from tall oil fatty acid, oleic acid, and linoleic acid. Other suitable corrosion inhibitors include long-chain alpha- and omega-dicarboxylic acids in the molecular weight range of about 600 to about 3000, and alkenyl succinic acids in which the alkenyl group contains about 10 or more carbon atoms, such as tetrapropenyl succinic acid, tetradecenyl succinic acid, and hexadecenyl succinic acid. Another useful type of acidic corrosion inhibitor is the half ester of an alkenyl succinic acid having about 8 to about 24 carbon atoms in the alkenyl group with an alcohol, such as a polyglycol. The corresponding half amides of such alkenyl succinic acids are also useful. Useful rust inhibitors are high molecular weight organic acids. In some embodiments, the engine oil does not contain a rust inhibitor.

[0110] When present, rust inhibitors may be used in any amount sufficient to provide from about 0 wt. % to about 5 wt. %, from about 0.01 wt. % to about 3 wt. %, from about 0.1 wt. % to about 2 wt. %, based on the final weight of the lubricating oil composition.

[0111] The lubricant composition may also include a corrosion inhibitor (it should be noted that some of the other mentioned components may also have copper corrosion inhibiting properties). Suitable copper corrosion inhibitors include ether amines, polyethoxylated compounds such as ethoxylated amines and ethoxylated alcohols, imidazolines, mono- and di-alkyl thiadiazoles, and the like.

[0112] Thiazoles, triazoles, and thiadiazoles may also be used in the lubricant. Examples include benzotriazole, tolyltriazole, octyltriazole, decyltriazole, dodecyltriazole, 2-mercaptobenzothiazole, 2,5-dimercapto-1,3,4-thiadiazole, 2-mercapto-5-hydrocarbylthio-1,3,4-thiadiazole, and 2-mercapto-5-hydrocarbyldithio-1,3,4-thiadiazole. In one embodiment, the lubricant composition includes a 1,3,4-thiadiazole, such as 2-hydrocarbyldithio-5-mercapto-1,3,4-dithiadiazole.

[0113] Antifoam agents / surfactants may also be included in the fluids according to the present invention. Various agents are known for such applications. A copolymer of ethyl acrylate and hexyl ethyl acrylate, such as PC-1244 available from Solutia, may be used. In other embodiments, a silicone fluid, such as 4% DCF, may be included. Mixtures of antifoam agents may also be present in the lubricant composition. [Example]

[0114] The following examples illustrate exemplary embodiments of the present disclosure. In these examples, as well as elsewhere in this application, all ratios, parts, and percentages are by weight unless otherwise indicated. It is intended that these examples are presented for illustrative purposes only and are not intended to limit the scope of the invention disclosed herein.

[0115] Example 1

[0116] Comparative transmission lubricating fluids and transmission lubricating fluids of the present invention were prepared with the compositions shown in Table 3 below. Despite variations in the phosphite component, the lubricants contained the same additive amounts, including extreme pressure agents, antifoam agents, friction modifiers, esters, dispersants, pour point depressants, detergents, antioxidants, and viscosity index improvers, as shown in Table 3 below. Inventive 1, Comparative Example 2, and Comparative Example 3 were identical except for the phosphite changes. The differences are shown in Table 3 below. All fluids were formulated to achieve a kV100 of approximately 4.5 cSt (kV100 measured according to ASTM D425). Comparative Example 1 contained no phosphite and a slightly higher amount of base oil.

[0117] [Table 3]

[0118] The ingredients in Table 3 above included the following: The thiadiazole additive is an 85:15 mixture of 2,5-bis-(hydrocarbyldithio)-1,3,4-thiadiazole and 5-hydrocarbyldithio-2-mercapto-1,3,4-thiadiazole, where the hydrocarbyl groups are C8-C 12 The compound contained about 35 weight percent sulfur and about 6.4 weight percent nitrogen. Phosphite A was tris(2,4-di-tert-butylphenyl)phosphite having about 4.8 weight percent phosphorus. Phosphite A was therefore a trisphenylphosphite having dialkylations on each aryl ring, with each alkylation located in the ortho and para positions. Phosphite A therefore had a ratio of para substitution to ortho substitution of 1.0. • Phosphite B was a trisnonylphenyl phosphite having about 4.5 weight percent phosphorus with only ortho substitution, thus a para to ortho substitution ratio of 0. ● Phosphite C was a blend of tris-aryl phosphites having either para-substitution or a combination of ortho- and para-substitution with branched C5 alkyl groups. Phosphite C was approximately 5.1 weight percent phosphorus. All of the aryl rings in the blend of tris-aryl phosphites were alkylated at the para position. Only about 24.4% of the aryl rings in the blend of tris-aryl phosphites were alkylated at the ortho position. Thus, Phosphite C had an overall ratio of para- to ortho-substitution of 4.1:1. The blend included at least tris(4-(tert-pentyl)phenyl)phosphite, 2,4-di-tert-pentylphenylbis(4-(tert-pentyl)phenyl)phosphite, and bis(2,4-di-tert-pentylphenyl)(4-(tert-pentyl)phenyl)phosphite.

[0119] The lubricants in Table 3 were evaluated for copper tarnish according to a modified ASTM D130 leach (extended to 168 hours at 150°C). After the ASTM D130 test, the lubricants were tested for copper leach using ICP. Invention 1 was also evaluated for load-carrying performance or passing the FZG breaking load stage according to CEC L-84-02 (A10 / 16.6R / 90C). The results are provided in Table 4 below.

[0120] [Table 4]

[0121] Comparative Lubricant 1, a baseline example containing the thiadiazole additive but no phosphite, showed poor copper corrosion with high levels of copper leach and high copper tarnish ratings. Inventive Lubricant 1, containing the thiadiazole additive and Phosphite A, showed low end-test copper leach and had improved copper tarnish ratings. Comparative Lubricants 2 and 3 had slightly improved copper performance compared to Comparative Lubricant 1, but they still performed significantly poorer than Inventive Lubricant 1. Only Inventive Lubricant 1, containing a phosphite with the stated ratio of para- to ortho-substitution, achieved passing copper corrosion (with respect to leaching and tarnish) while maintaining adequate load-carrying performance when combined with the thiadiazole additive.

[0122] It should be noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless expressly and unambiguously limited to one referent. Thus, for example, a reference to an "antioxidant" includes two or more different antioxidants. As used herein, the term "comprises" and grammatical variations thereof are intended to be open-ended, such that the recitation of items in a list does not exclude other similar items that may be substituted for or added to the listed items.

[0123] For purposes of this specification and the appended claims, unless otherwise indicated, all numbers expressing quantities, percentages, or proportions, and other numerical values ​​used in the specification and claims should be understood as being modified in all instances by the term "about." Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and appended claims are approximations that may vary depending upon the desired properties sought to be obtained by the present disclosure. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0124] It is understood that each component, compound, substituent, or parameter disclosed herein should be construed as disclosed for use alone or in combination with one or more of any and all other components, compounds, substituents, or parameters disclosed herein.

[0125] It is further understood that each range disclosed herein should be construed as a disclosure of each specific value within the disclosed range having the same number of significant digits. Thus, for example, a range of 1 to 4 should be construed as an explicit disclosure of not only the values ​​1, 2, 3, and 4, but also any range of such values.

[0126] It should be further understood that each lower limit of each range disclosed herein should be interpreted as being disclosed in combination with each upper limit of each range and each specific value within each range for the same component, compound, substituent, or parameter. Thus, the present disclosure should be interpreted as a disclosure of all ranges derived by combining each lower limit of each range with each upper limit of each range, or each specific value within each range, or by combining each upper limit of each range with each specific value within each range. In other words, it is also further understood that any range between the endpoints within a broad range is also contemplated herein. Thus, a range of 1 to 4 also means ranges of 1 to 3, 1 to 2, 2 to 4, 2 to 3, etc.

[0127] Furthermore, a specific amount / value of a component, compound, substituent, or parameter disclosed in the description or examples should be construed as a disclosure of either a lower or upper limit of a range and, therefore, can be combined with any other lower or upper limit of a range or specific amount / value for the same component, compound, substituent, or parameter disclosed elsewhere in this application to form a range for that component, compound, substituent, or parameter.

[0128] While particular embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents may occur that are not presently anticipated or presently unforeseeable to Applicants or others skilled in the art. Accordingly, the appended claims as filed, and the appended claims as they may be amended, are intended to cover all such alternatives, modifications, variations, improvements, and substantial equivalents.

Claims

1. 1. A lubricating composition suitable for use in a vehicle transmission, comprising: one or more base oils of lubricating viscosity; at least about 0.35 weight percent of a thiadiazole additive; and one or more substituted trisarylphosphites having an overall ratio of para- to ortho-substitution between about 0.5 and about 2.

0.

2. the one or more trisarylphosphites do not include meta substitution, and / or the para and ortho substitutions of the one or more triarylphosphites are independently selected from the group consisting of C １ ~C ６ 2. The lubricating composition of claim 1, wherein the hydrocarbyl group is a straight or branched chain, and / or the one or more trisarylphosphites comprise tris(2,4-di-tert-butylphenyl)phosphite.

3. 3. The lubricating composition of claim 2, wherein the hydrocarbyl groups are selected from n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, or combinations thereof.

4. 3. The lubricating composition of claim 2, wherein the tris(2,4-di-tert-butylphenyl)phosphite is present in the lubricating composition at about 0.5 wt. %.

5. 2. The lubricating composition of claim 1, wherein the one or more substituted trisarylphosphites have an overall ratio of para to ortho substitution of between about 0.8 and about 1.2, and / or further comprising about 0.2 to about 0.6 weight percent of the one or more substituted trisarylphosphites.

6. 6. The lubricating composition of claim 5, wherein the one or more substituted trisarylphosphites have an overall ratio of para to ortho substitution of between about 0.9 and about 1.

0.

7. 7. The lubricating composition of claim 6, wherein the one or more substituted trisarylphosphites have an overall ratio of para to ortho substitution of about 1.

0.

8. 10. The lubricating composition of claim 1, wherein the lubricating composition exhibits a copper tarnish rating of 3B or less according to ASTM D130 after 168 hours at 150°C, contains no more than about 20 ppm copper leach after testing according to ASTM D130 after 168 hours at 150°C, and exhibits a failure load stage of 7 or greater according to the FZG test of CEC L-84-02 (A10 / 16.6R / 90C).

9. 10. The lubricating composition of claim 1, wherein the thiadiazole additive is selected from a monohydrocarbyl thiol-substituted thiadiazole, a bishydrocarbyl thiol-substituted thiadiazole, or a combination thereof.

10. the thiadiazole additive comprises 2,5 dimercapto-1,3,4-thiadiazole, and / or the 2,5 dimercapto-1,3,4-thiadiazole comprises 2,5-bis-(nonyldithio)-1,3,4-thiadiazole and 2,5-mono-(nonyldithio)-1,3,4-thiadiazole (e.g., at about 10 to about 25%), and / or the lubricating composition comprises up to about 0.5 weight percent of the thiadiazole additive, and / or the thiadiazole additive comprises one or more compounds having the structure of Formula I; 【Chemistry 1】 During the ceremony, Each R ３ are independently hydrogen or sulfur; Each R ４ are independently an alkyl group; n is an integer of 0 or 1, and R ３ is hydrogen, the adjacent R ４ The integer n in the moiety is 0, and R ３ is sulfur, the adjacent R ４ the n in the moiety is 1; At least one R ３ The lubricating composition of claim 9, wherein is sulfur.

11. 1. A method of lubricating a transmission, comprising: lubricating the transmission with the lubricating composition; The lubricating composition comprises one or more base oils of lubricating viscosity, at least about 0.35 weight percent of a thiadiazole additive, and one or more substituted trisarylphosphites having an overall ratio of para-substitution to ortho-substitution between about 0.5 and about 2.

0.

12. the one or more trisarylphosphites do not include meta substitutions, and / or the para and ortho substitutions of the one or more triarylphosphites are independently selected from the group consisting of C １ ~C ６ 12. The method of claim 11, wherein the hydrocarbyl group is a linear or branched hydrocarbyl group.

13. The method of claim 11, wherein the hydrocarbyl groups are selected from n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, or combinations thereof.

14. 12. The method of claim 11, wherein the one or more trisarylphosphites comprise tris(2,4-di-tert-butylphenyl)phosphite.

15. 12. The method of claim 11, wherein the steel exhibits a copper tarnish rating of 3B or less according to ASTM D130 after 168 hours at 150°C, contains no more than about 20 ppm copper leach after testing according to ASTM D130 after 168 hours at 150°C, and exhibits a failure load stage of 7 or greater according to the FZG test of CEC L-84-02 (A10 / 16.6R / 90C).

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