Gear fluid and wet brake lubricating composition

Abstract

To provide a single lubricant composition suitable for wet brakes, gears, and differentials, the composition having improved properties with respect to extreme pressure, friction, and copper corrosion.SOLUTION: A lubricant composition comprises one or more base oils having a lubricating viscosity, an extreme-pressure agent that provides more than 1.5 wt.% and up to 3 wt.% of sulfur, a first phosphorus-containing component, a second phosphorus-containing component, a third phosphorus-containing component, a thiadiazole or a derivative thereof, and a hydrocarbylamine compound, wherein the lubricant composition contains from about 0.1 to about 0.5 wt.% of total amine compounds provided from the second phosphorus-containing component, the third phosphorus-containing component, and the hydrocarbylamine compound, about 15 to about 25 wt.% of the total amine compounds is provided by the hydrocarbylamine compound, more than 50 wt.% of the total amine compounds is provided by the second phosphorus-containing component, and about 20 to about 30 wt.% of the total amine compounds is provided by the third phosphorus-containing component.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a single lubricating composition suitable for wet brakes, gears, and differentials that has improved extreme pressure, friction, and copper corrosion properties. [Background technology]

[0002] In heavy-duty or industrial applications, wet brakes, gears, differentials, and axles are often lubricated from a common fluid provided through a single reservoir that must meet the extreme pressure requirements for lubricating the gears, transmissions, and axles, but also the friction requirements of the clutches and / or wet brakes. For example, axles, transfer cases, and / or differentials in heavy-duty or industrial applications have various mechanisms for transmitting power and / or torque, e.g., from the input pinion gear to the opposing wheels on the axle shaft. Lubricants for such applications typically require the fluid to have adequate extreme pressure and copper corrosion performance suitable for the high loads experienced by the equipment. To achieve the desired extreme pressure performance, several additives may be included in the lubricant. For example, such lubricants often contain sulfurized additives to protect gears and other components from wear and scoring. However, while sulfurized additives can provide good extreme pressure and wear / scoring performance for the desired application, conventional sulfurized additives tend to be detrimental to copper and copper alloys, resulting in unacceptable copper corrosion and friction.

[0003] Heavy-duty and industrial equipment may also use wet clutches and / or wet brakes, and the same fluid used to lubricate gears and axles may also be used in the wet clutch or brake system, where friction performance must be controlled and additives suitable for extreme pressure and general lubrication are not always suitable for improved friction performance.

[0004] However, with the ever-challenging requirements of so many competing performance results, there tends to be a challenge in balancing the composition additives to achieve all performance attributes. In many situations, for example, varying one component or adding an additional component in a lubricant composition to improve a performance characteristic tends to adversely affect one or more other performance characteristics. Therefore, it becomes difficult to balance all competing performance requirements with limited lubricant additives. Summary of the Invention

[0005] In one approach or embodiment, a lubricating composition comprises one or more base oils of lubricating viscosity, up to about 3 wt. % sulfur provided by an extreme pressure agent, and a first phosphorus-containing component comprising a hydrocarbyl phosphonic acid monoester, wherein in some embodiments the first phosphorus-containing component is substantially amine-free or substantially amine-free (e.g., less than about 0.05 wt. % amine component, less than about 0.02 wt. % amine component, less than about 0.01 wt. % amine component, or functional amount). a first phosphorus-containing component, a second phosphorus-containing component comprising an amine salt of a dialkyl hydrogen thiophosphite, and a dialkyl phosphorodithioic acid (preferably O,O'-di(4-methyl-2-pentanyl)phosphorodithioic acid) with ethylene and / or propylene oxide to provide a first reaction product; further reacting the first reaction product with phosphorus pentoxide to provide a second reaction product; and neutralizing the second reaction product with one or more aliphatic primary amines (preferably tertiary aliphatic primary amines) to provide a third amine. and a thiadiazole or derivative thereof selected from a mono-hydrocarbylthiol-substituted thiadiazole, a bis-hydrocarbylthiol-substituted thiadiazole, or a combination thereof, wherein the lubricating composition comprises from about 0.1 to about 0.5 weight percent of the hydrocarbyl amine compound provided by the second phosphorus-containing component, the third phosphorus-containing component, and the hydrocarbyl amine compound, wherein the hydrocarbyl amine compound is less than about 0.1 weight percent of the hydrocarbyl amine compound. Total containing an amine compound, and The total of the above about 15 to about 25 weight percent of the amine compounds are provided by hydrocarbyl amine compounds; The total of the above greater than 50% by weight of the amine compound is provided by the second phosphorus-containing component; The total of the above In another embodiment, the extreme pressure agent is provided by a blend of organic sulfur compounds, each of which independently has the formula R1-S. x-R2, where R1 and R2 are independently a C2-C20 hydrocarbyl group and x is an integer from 2 to 6, and the blend of organosulfide compounds provides from about 14,000 ppm to about 16,000 ppm of sulfur in the organosulfide compound from organosulfide compounds having S2 and S3 moieties and up to about 3,000 ppm of sulfur from organosulfide compounds having S4, S5, and / or S6 moieties.

[0006] In yet other approaches or embodiments, the lubricating compositions described in the preceding paragraph may include other features or embodiments, in any combination. These other features or embodiments may include one or more of the following: a hydrocarbyl phosphonic acid monoester; The total of the aboveand / or the lubricating composition contains from about 1.3 to about 3 weight percent total sulfur, at least about 90 weight percent of the total sulfur being provided by the extreme pressure agent as a blend of organic sulfide compounds, the blend having from about 10 to about 15 weight percent organic sulfide compounds having an S2 moiety, from about 60 to about 70 weight percent compounds having an S3 moiety, and from about 12 to about 20 weight percent compounds having an S4 moiety; and / or the blend of organic sulfide compounds is provided by a first organic sulfide reaction product and a second organic sulfide reaction product; and / or the hydrocarbyl amine compound is a tertiary-aliphatic primary amine having from 4 to 20 carbon atoms in the alkyl group; and / or the hydrocarbyl amine compound is selected from the group consisting of tertiary butylamine, tertiary hexyl primary amine, 1-methyl-1-amino-cyclohexane, tertiary octyl primary amine, tertiary decyl primary amine, and the like. and / or the lubricating composition comprises from about 1.5 to about 2.8 wt % of a first organic sulfide reaction product and from about 1.5 to about 2.8 wt % of a second organic sulfide reaction product; and / or the lubricating composition comprises a weight ratio of the first organic sulfide reaction product to the second organic sulfide reaction product of from about 0.8:1 to about 1:0.8; and / or R1 and R2 are independently selected from propyl, isopropyl, butyl, isobutyl, tert-butyl, or combinations thereof; and / or (a) the hydrocarbyl phosphonic acid monoester has a structure of Formula II:

[0007] [ka] In the formula, R5 is C 12 ~C 30 R is a hydrocarbyl group, R is a C1-C4 alkyl group, and R ’is hydrogen or an alkyl group, and / or the lubricating composition comprises from about 0.1 wt % to about 0.8 wt % of a hydrocarbyl phosphonic acid monoester, and / or the lubricating composition further comprises a thiadiazole or derivative thereof selected from a monohydrocarbyl thiol-substituted thiadiazole, a bishydrocarbyl thiol-substituted thiadiazole, or a combination thereof, and / or the thiadiazole is a 1,3,4-thiadiazole or derivative thereof, and / or the lubricating composition comprises about 1 wt % or less of a thiadiazole or derivative thereof, and / or the thiadiazole or derivative thereof comprises one or more compounds having the structure of Formula I,

[0008] [ka] 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 the lubricating composition exhibits a reduction in lubrication time of about 100 mm in an FZG sprung test at 90°C at load stage 9 or greater compared to a reference fluid. 2 and a hydrocarbyl phosphonic acid monoester solubilized in one or more base oils exhibiting less than about 200 mg copper corrosion in accordance with ASTM D130, and / or the second phosphorus-containing component is an amine salt of dibutyl hydrogen thiophosphate.

[0009] In yet other embodiments and approaches of the present disclosure, use of any embodiment of the lubricating composition of this inventive summary provides a lubricating fluid with a lubricating oil resistance of about 100 mm in an FZG spring test at 90° C. or above load stage 9 when compared to a reference fluid. 2and copper corrosion of about 200 mg or less with a hydrocarbyl phosphonic acid monoester solubilized in one or more base oils in accordance with ASTM D130, and more particularly, a lubricating composition comprising: up to about 3 wt. % sulfur from an extreme pressure agent; a first phosphorus-containing component comprising a hydrocarbyl phosphonic acid monoester, the first phosphorus-containing component preferably being substantially amine-free or amine-free as described above; a second phosphorus-containing component comprising an amine salt of a dialkyl hydrogen thiophosphite; and a dialkyl phosphorodithioic acid (preferably O,O'-di(4-methyl-2-pentanyl) phosphorodithioic acid) dissolved in ethylene and / or propane. and a third amine-containing phosphorus component prepared by reacting a thiadiazole compound with pyrene oxide to provide a first reaction product, further reacting the first reaction product with phosphorus pentoxide to provide a second reaction product, and neutralizing the second reaction product with one or more aliphatic primary amines (preferably tertiary aliphatic primary amines) to provide a third amine-containing phosphorus component; a thiadiazole component; and a hydrocarbyl amine compound, wherein the hydrocarbyl amine compound is no more than about 0.1 wt. % of the hydrocarbyl amine compound, wherein the lubricating composition comprises from about 0.1 to about 0.5 wt. % of the hydrocarbyl amine compound provided from the second phosphorus-containing component, the third phosphorus-containing component, and the hydrocarbyl amine compound. Total containing an amine compound, and The total of the above about 15 to about 25 weight percent of the amine compounds are provided by hydrocarbyl amine compounds; The total of the above greater than 50% by weight of the amine compound is provided by the second phosphorus-containing component; The total of the above About 20 to about 30 weight percent of the amine compound is provided by the third phosphorus-containing component, and the resulting fluid exhibits a resistance of about 100 mm in an FZG spring test at 90°C and load stage 9 or greater when compared to a reference fluid. 2 and use of a lubricating composition to achieve less than about 200 mg copper corrosion per ASTM D 130 with a hydrocarbyl phosphonic acid monoester solubilized in one or more base oils. In another approach, the extreme pressure agent comprises a blend of organic sulfide compounds, each organic sulfide compound independently represented by the formula R1-S x-R2, where R1 and R2 are independently a C2-C20 hydrocarbyl group and x is an integer from 2 to 6, and the blend of organosulfide compounds provides from about 14,000 ppm to about 16,000 ppm of sulfur in the organosulfide compound from organosulfide compounds having S2 and S3 moieties and up to about 3000 ppm of sulfur from organosulfide compounds having S4, S5, and / or S6 moieties.

[0010] Further described herein are other approaches or embodiments, including a system of gears, differentials, and wet brakes all lubricated from any embodiment of the lubricating composition of this inventive summary, where the lubricating composition is provided from a common fluid reservoir, tank, and / or sump. In yet another embodiment, described herein are methods of lubricating gears, differentials, and / or wet brakes with any embodiment of the lubricating composition of this inventive summary, where the lubricating composition is provided from a common fluid reservoir, tank, and / or sump.

[0011] 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. DETAILED DESCRIPTION OF THE INVENTION

[0012] In one approach or embodiment, lubricating compositions suitable for limited-slip applications, including gears, differentials, and axles, as well as wet clutches and / or wet brakes, are disclosed herein. The fluids herein have balanced extreme pressure performance suitable for gear applications and friction performance suitable for wet clutch and / or wet brake applications. In one aspect, the lubricating compositions herein include at least one or more base oils of lubricating viscosity; an extreme pressure agent (in some embodiments, the extreme pressure agent is provided by a blend of organic sulfide compounds) imparting up to about 3 wt. % sulfur, up to about 2 wt. % sulfur, or greater than about 1.5 wt. % sulfur and less than or equal to 3 wt. % sulfur; at least three distinct phosphorus-containing components (one preferably amine-free and the other two preferably amine-containing phosphorus components); a hydrocarbyl amine compound; and a thiadiazole or derivative thereof selected from monohydrocarbyl thiol-substituted thiadiazoles, bishydrocarbyl thiol-substituted thiadiazoles, or combinations thereof. As shown by the following examples, such compounds provide sufficient extreme pressure performance.

[0013] In one embodiment, the lubricants herein comprise an extreme pressure agent as a blend of organic sulfide compounds to provide extreme pressure performance. In one aspect, each organic sulfide compound in the blend is independently represented by the formula R1-S x -R2, where R1 and R2 are independently a C2 to C20 hydrocarbyl group and x is an integer from 2 to 6. In another embodiment, the blend of organosulfide compounds provides from about 14,000 ppm to about 16,000 ppm of sulfur in the organosulfide compound from organosulfide compounds having S2 and S3 moieties, and less than 3000 ppm, preferably from about 2500 to about 3000 ppm of sulfur from organosulfide compounds having S4, S5, and / or S6 moieties.

[0014] In other embodiments, the lubricants herein also contain at least three separate phosphorus-containing components as friction modifiers. In one aspect, the three phosphorus-containing components include: (1) a first phosphorus-containing component in the form of a hydrocarbyl phosphonic acid monoester, preferably, the first phosphorus-containing component is substantially amine-free or amine-free, as defined above; (2) a second phosphorus-containing component in the form of an amine salt of a dialkyl hydrogen thiophosphite; and (3) a third phosphorus-containing component prepared by reacting a dialkyl phosphorodithioic acid (preferably O,O'-di(4-methyl-2-pentanyl)phosphorodithioic acid) with ethylene and / or propylene oxide to provide a first reaction product, further reacting the first reaction product with phosphorus pentoxide to provide a second reaction product, and neutralizing the second reaction product with one or more aliphatic primary amines (preferably tertiary aliphatic primary amines) to provide the third amine-containing phosphorus component.

[0015] In embodiments, the lubricants herein also contain a hydrocarbyl amine compound. In one aspect, the hydrocarbyl amine compound is an aliphatic tertiary primary amine. In other aspects, the lubricants herein contain less than about 0.1 wt. % of a hydrocarbyl amine compound (and any additive package or additive concentrate contains less than about 10 wt. % of a hydrocarbyl amine compound).

[0016] In yet another approach or embodiment, the lubricating compositions herein also comprise from about 0.1 to about 0.5 wt. % of a phosphorus-containing compound provided by the second phosphorus-containing component, the third phosphorus-containing component, and the hydrocarbyl amine compound combined. Total In another approach or embodiment, The total of the above about 15 to about 25 weight percent of the amine compounds are provided by hydrocarbyl amine compounds; The total of the above greater than 50% by weight of the amine compound is provided by the second phosphorus-containing component; The total of the aboveAbout 20 to about 30 weight percent of the amine compound is provided by the third phosphorus-containing component. As demonstrated by the examples below, the selection of three phosphorus-containing components in combination with the hydrocarbyl amine compound achieves the desired friction and copper corrosion performance along with the extreme pressure performance achieved by the organosulfide compound. Each of the components of the lubricating compositions herein is further described below.

[0017] extreme pressure agents In some embodiments, the lubricating compositions herein include an extreme pressure agent that provides up to about 3 wt. % sulfur, up to about 2 wt. % sulfur, or from about 1 wt. % to about 3 wt. %, from about 1.5 wt. % to about 3 wt. %, or from about 1.5 wt. % to about 2 wt. % sulfur. In one embodiment, the extreme pressure agent is a blend of organosulfide compounds provided by combining two or more different organosulfide compounds in one embodiment or approach. In one approach, the combined first and second organosulfide compounds provide up to about 3 wt. % sulfur (preferably up to 3 wt. % sulfur), preferably from about 1 to about 3 wt. % sulfur (preferably from about 1 to about 3 wt. % or from about 1.5 to about 3 wt. % sulfur, or from about 1.5 to about 2 wt. % sulfur) in the composition. In another approach, the blend of organic sulfide compounds provides at least about 90 weight percent or more of the total sulfur in the lubricating composition, and in another approach, the combined organic sulfide compounds provide from about 90 to about 99 weight percent of the total sulfur in the lubricating composition, or from about 95 to about 98 weight percent of the total sulfur in the lubricating composition.

[0018] Each organosulfide compound in the blend is derived from a reaction product containing a specific combination / ratio of different organosulfide compounds with a specific contribution of sulfur provided by the S2-S6 moieties in the compound. More specifically, each organosulfide compound in the blend herein has the formula R1-S xDihydrocarbyl sulfide compounds having the structure -R2 (Formula I), where R1 and R2 in Formula I are independently C2-C20 hydrocarbyl groups, and x is an integer of at least 2 (preferably 2-6, 2-5, or 2-4) suitable for achieving the sulfur contribution, ratio, and profile described herein. That is, each hydrocarbyl group of the organic sulfide independently has 2-20 carbon atoms, preferably 3-10 carbon atoms, or more preferably 3-4 carbon atoms. In this approach, each hydrocarbyl group of the organic sulfide compound may be aromatic or aliphatic. Preferably, the hydrocarbyl group may be an aliphatic group such as alkyl, alkenyl, cycloalkyl, cycloalkylalkyl, aryl, aralkyl, or cycloalkenyl. Most preferably, the hydrocarbyl group is an alkyl group. Suitable alkyl groups may be propyl, isopropyl, butyl, isobutyl, and / or tert-butyl groups. In this approach, each hydrocarbyl group may be derived from an olefin. In such an approach, the olefin may have from 2 to 20 carbon atoms, or other ranges as described above.

[0019] Suitable olefins for preparing each of the organic sulfide compounds herein may be mono- or di-substituted monoolefins of 2 to 12 carbon atoms. Disubstituted monoolefins are olefins having at least one double-bonded carbon atom with two alkyl substituents. Examples of suitable olefins from which to derive the organic sulfides include ethylene, propylene, butylene, isobutylene, 2-methyl-2-pentene, 2-methyl-2-butene, 2-methyl-1-butene, diisobutylene, triisobutylene, and mixtures thereof, as well as dimers, trimers, tetramers, and mixtures thereof, which may be suitable hydrocarbyl groups for each of the organic sulfides herein.

[0020] Each of the organic sulfide compounds herein can be prepared by reacting one or more of the above hydrocarbyl or olefinic compounds with a sulfur source (preferably elemental sulfur or molten sulfur) in the presence or absence of a catalyst, such as an optional alkylamine catalyst, optionally under superatmospheric pressure, followed by removal of low-boiling materials. Preferably, the sulfur source is substantially free of sulfur chlorides, hydrogen sulfide, and combinations thereof; in this context, reactions herein have about 0.1 wt. % or less, about 0.05 wt. % or less, about 0.01 wt. % or less, or no sulfur chlorides, hydrogen sulfide, etc.

[0021] In embodiments, suitable organic sulfides herein can be obtained, for example, by combining or reacting an olefin or hydrocarbyl compound with elemental sulfur in an autoclave or other reaction vessel suitable for conducting superatmospheric pressure and high temperature reactions in a ratio of moles of olefin / hydrocarbyl to grams of sulfur of from about 2:1 to about 1:2. In this approach, the reaction can be carried out at a temperature of from about 100° C. to about 200° C., a pressure of from about 250 to about 1,000 psi, and a reaction time of from about 2 to about 30 hours, as needed to achieve the desired sulfur level for each additive in the mixture.

[0022] The reaction can be carried out with or without a catalyst. Suitable catalysts, if used, include amines and sulfur compounds such as dithiocarbamate salts and mercaptans, including, but not limited to, n-butylamine, n-octylamine, triethylamine, tetramethylthiuram disulfide, and mercaptobenzothiazole. Catalysts can be used, if desired, in amounts of about 0.01 to about 5.0 weight percent of the reaction mixture, or other amounts appropriate for the particular application and sulfur level. The reaction can be carried out in the absence of oxygen.

[0023] The sulfurized olefin or sulfurized hydrocarbyl intermediate may then be treated with caustic and / or an alkali metal sulfide such as sodium sulfide or potassium sulfide, optionally with an aqueous solution of sodium sulfide, for example, by treating sodium hydrosulfide and caustic solutions (such as aqueous sodium hydroxide) to achieve the desired sulfide profile / ratio (e.g., -S x The solution can be prepared by mixing the sodium sulfide solution and the sulfurized intermediate in amounts effective to produce the desired S3 sulfur group. The solution can contain a co-solvent, such as methanol. The sodium sulfide solution and sulfurized intermediate can be mixed in a stirred reactor and heated under an inert atmosphere, such as nitrogen, at a temperature of up to about 100°C, such as from about 50°C to about 100°C, for about 30 minutes to about 4 hours, and in some cases, for about 1 to about 2 hours. The reaction mixture can then be cooled, and the separated organic product recovered on top of the aqueous layer. The amount of caustic can be varied as needed to form each of the organic sulfide compounds and to provide sulfur contributions from the stated sulfur profile / ratio. That is, a first organic sulfide compound, which may have a high level of S3 sulfur groups, can be treated with a higher level of caustic, while a second organic sulfide compound, which has a balanced mixture of S3 and S4 groups, can be treated with a lower amount of caustic. In one embodiment, the first organic sulfide compound is treated with at least twice the amount of caustic as the second organic sulfide compound.

[0024] In one approach or embodiment, the blend of organosulfur compounds (i.e., all organosulfur compounds combined) of the lubricating compositions herein provides from about 14,000 ppm to about 16,000 ppm of sulfur in the organosulfur compounds from organosulfur compounds having S2 and S3 moieties, and from about 2,500 to about 3,000 ppm of sulfur from organosulfur compounds having S4 or higher sulfur moieties, preferably S4, S5, and / or S6 moieties. In another approach or embodiment, about 12 to about 20 wt% (in another approach, about 12 to about 16 wt%) of the organosulfide compounds in the blend have S2 moieties, about 60 to about 75 wt% (in another approach, about 65 to about 75 wt%) of the organosulfide compounds in the blend have S3 moieties, about 12 to about 20 wt% (in another approach, about 12 to about 18 wt%) of the organosulfide compounds in the blend have S4 moieties, about 0.5 to about 5 wt% (in another approach, about 0.5 to about 3 wt%) of the organosulfide compounds in the blend have S5 moieties, and about 1 wt% or less (in another approach, about 0.5 wt% or less or a non-functional amount) of the organosulfide compounds in the blend have S6 moieties. This blend of total organosulfide compounds is preferably provided by the reaction product of at least two different organosulfide combinations. In another approach, the organic sulfide compounds in the blend are a combination of organic sulfide compounds having a selected weight ratio of S3 moieties to S4 moieties, for example, a weight ratio of S3 moieties to S4 moieties of about 3:1 to about 6:1 (in another approach, about 4:1 to about 5.5:1).

[0025] In any embodiment herein, the first organosulfide compound is a reaction product of organosulfide compounds containing a majority of compounds having an S3 moiety, preferably a combination of organosulfide compounds having about 12 to about 18 wt % (in other embodiments, about 12 to about 16 wt %) of organosulfide compounds having an S2 moiety, about 70 to about 90 wt % (in other embodiments, about 80 to about 90 wt %) of organosulfide compounds having an S3 moiety, about 1 to about 6 wt % (in other embodiments, about 2 to about 5 wt %) of organosulfide compounds having an S4 moiety, about 1 wt % or less (in other embodiments, about 0.5 wt % or less or a non-functional amount) of organosulfide compounds having an S5 moiety, and about 1 wt % or less (in other embodiments, about 0.5 wt % or less or a non-functional amount) of organosulfide compounds having an S6 moiety. In another approach, the first reaction product of the organic sulfide compound can have a weight ratio of S3 moieties to S4 moieties of about 20:1 to about 30:1 (in another approach, about 25:1 to about 30:1).

[0026] In any embodiment herein, the second organosulfide compound is a second reaction product of organosulfide compounds comprising a more balanced blend of compounds having S3 and S4 moieties, preferably comprising a combination of organosulfide compounds having about 12 to about 18% (in other embodiments, about 12 to about 16% by weight) of organosulfide compounds having S2 moieties, about 50 to about 60% (in other embodiments, about 55 to about 60% by weight) of organosulfide compounds having S3 moieties, about 20 to about 30% (in other embodiments, about 20 to about 26% by weight) of organosulfide compounds having S4 moieties, about 1 to about 5% (in other embodiments, about 1 to about 4% by weight) of organosulfide compounds having S5 moieties, and about 1% or less (in other embodiments, about 0.5% or less by weight or a non-functional amount) of organosulfide compounds having S6 moieties. In another approach, the second reaction product of the organic sulfide compound can have a weight ratio of S3 moieties to S4 moieties of about 1.5:1 to about 4:1 (in another approach, about 2:1 to about 3:1).

[0027] In yet another approach or embodiment, the lubricating compositions herein may comprise a treat rate of organosulfide compounds provided by (1) about 1.5 to about 2.8 wt. % (in another approach, about 1.6 to about 2.2 wt. %) of a first reaction product of organosulfide compounds, and (2) about 1.5 to about 2.8 wt. % (in another approach, about 1.6 to about 2.2 wt. %) of a second reaction product of organosulfide compounds. Of course, the amount of each reaction product will depend on the composition of sulfur compounds within each reaction product. In some approaches, it is preferred that the final fluid contain no more than 3 wt. % sulfur compounds having S5 sulfur groups, more than about 60 wt. % sulfur compounds having S3 groups, and / or less than 20 wt. % sulfur compounds having S4 groups. In yet another approach, the lubricating compositions may have a weight ratio of the first organosulfide reaction product to the second organosulfide reaction product of about 0.8:1 to about 1:0.8.

[0028] As shown in the examples below, selecting a particular combination of organic sulfide reaction products helps achieve good friction performance, good wear scar performance, and good copper corrosion performance. Moreover, although high levels of sulfur are typically detrimental to copper corrosion, when the lubricating compositions herein contain specific profiles / ratios of organic sulfur compounds, the compositions can surprisingly contain higher levels of total sulfur and still achieve better copper corrosion performance than comparative fluids having lower levels of sulfur but not falling within the specific sulfur profile identified herein.

[0029] First Phosphorus-Containing Component The lubricating compositions herein include a first phosphorus-containing component in the form of an amine-free or substantially amine-free hydrocarbyl phosphonic acid monoester (i.e., providing less than about 0.05 wt. % amine compounds, less than 0.02 wt. % amine compounds, less than about 0.01 wt. % amine compounds, or any amine compounds that are not at functional levels). In some approaches, the amine-free hydrocarbyl phosphonic acid monoester has the structure of Formula II:

[0030] [ka] wherein R5, the hydrocarbyl portion of Formula II, is a linear or branched C12 to C30 hydrocarbyl chain; R6, the monoester portion of Formula II, is a linear or branched C1 to C4 alkyl group; and R ’ is hydrogen or an alkyl group, such as a C1-C30 alkyl group. In a preferred approach, R6 is a methyl or ethyl group and R' is hydrogen. The amount of phosphonic acid monoester, such as the hydrocarbyl phosphonic acid monoesters described herein, is from about 0.1 to about 1 wt. %, from about 0.1 to about 0.7 wt. %, and from about 0.1 to about 0.5 wt. %, based on the total weight of the lubricating oil composition.

[0031] Suitable phosphonic acids also include primary alkyl acyclic hydrocarbyl phosphonates in which the primary alkyl group can contain 1 to 4 carbon atoms and the acyclic hydrocarbyl group attached to the phosphorus atom contains 12 to 30 carbon atoms, in some approaches being linear hydrocarbyl groups without acetylenic unsaturation, in other approaches the acyclic hydrocarbyl group contains 12 to 24 carbon atoms, and in further approaches 12 to 20 carbon atoms.

[0032] Exemplary phosphonic acid compounds for the first phosphorus-containing component herein include methyl hydrocarbyl phosphonic acid, ethyl hydrocarbyl phosphonic acid, propyl hydrocarbyl phosphonic acid, butyl hydrocarbyl phosphonic acid, and isobutyl hydrocarbyl phosphonic acid, in each case preferably wherein the hydrocarbyl group is linear and saturated or contains one or more olefinic double bonds, each of which is preferably an internal double bond. Other suitable compounds include those in which the hydrocarbyl group attached to the phosphorus atom contains 16 to 20 carbon atoms or 18 to 20 carbon atoms. Particularly suitable phosphonic acid monoester compounds may be ethyl octadecyl phosphonic acid or methyl octadecyl phosphonic acid. Other examples of suitable phosphonate monoesters include, but are not limited to, compounds such as methyl triacontyl phosphonic acid, methyl triacotenyl phosphonic acid, methyl eicosyl phosphonic acid, methyl hexadecyl phosphonic acid, methyl hexadecenyl phosphonic acid, methyl tetracontenyl phosphonic acid, methyl hexacontyl phosphonic acid, methyl dodecyl phosphonic acid, methyl dodecenyl phosphonic acid, ethyl triacontyl phosphonic acid, ethyl triacotenyl phosphonic acid, ethyl eicosyl phosphonic acid, ethyl hexadecyl phosphonic acid, ethyl hexadecenyl phosphonic acid, ethyl tetracontenyl phosphonic acid, ethyl hexacontyl phosphonic acid, ethyl dodecyl phosphonic acid, ethyl dodecenyl phosphonic acid, and mixtures thereof.

[0033] Second Phosphorus-Containing Component The lubricating compositions herein include a second phosphorus-containing component in the form of an amine salt of a dihydrocarbyl hydrogen thiophosphite. The second phosphorus-containing component provides the amine compound to the lubricant from the amine salt. Suitable compounds for the second phosphorus-containing component, in some embodiments, include organic esters of phosphoric acid, phosphorous acid, or their amine salts. For example, the second phosphorus-containing component may include one or more of dihydrocarbyl phosphites, trihydrocarbyl phosphites, dihydrocarbyl phosphates, trihydrocarbyl phosphates, any sulfur analogs thereof, and any amine salts thereof. More specifically, in some preferred embodiments, the second phosphorus-containing component may include at least one amine salt of dibutyl hydrogen thiophosphite. In some approaches or embodiments herein, the lubricating compositions include about 0.1 to about 0.8 wt. % (alternatively, about 0.2 to about 0.8 wt. %, or about 0.4 to about 0.8 wt. %) of the second amine-containing phosphorus component.

[0034] The second phosphorus-containing component also provides an amine compound to the lubricants herein, which in embodiments is preferably salified with a hydrocarbyl amine. In embodiments, the hydrocarbyl amine salt provides about 0.1 to about 0.3 wt. % of the amine compound (in other embodiments, about 0.2 to about 0.3 wt. % of the amine compound) to the lubricating compositions herein. In this approach, the amine salt is a straight-chain aliphatic primary amine having a C6 to C30 hydrocarbyl group, or in other embodiments, a C10 to C20 hydrocarbyl group.

[0035] In another approach, suitable amines for salifying the second phosphorus-containing component herein include aliphatic amines, aromatic amines, cycloaliphatic amines, heterocyclic amines, carbocyclic amines, or combinations thereof. Preferably, the amine is a straight-chain aliphatic tertiary amine. In embodiments, the amine may have 4 to 30 carbon atoms. The amine may, in some approaches, include an aliphatic primary amine containing at least about 8 carbon atoms, and may have the structure R 14 NH2, where R 14is an aliphatic group such as, for example, tert-octyl, tert-dodecyl, tert-tetradecyl, tert-octadecyl, cetyl, behenyl, stearyl, eicosyl, docosyl, tetracosyl, hexatriacontanyl, and pentahexacontanyl. In other embodiments, suitable amines may be C11-C20 tertiary alkyl primary amines, more preferably C11-C14 tertiary alkyl primary amines. Additional amines may include, but are not limited to, cyclohexylamine, n-hexylamine, dodecylamine, di-dodecylamine, tri-dodecylamine, N-methyl-octylamine, butylamine, oleylamine, myristylamine, N-dodecyltrimethylenediamine, aniline, o-toluidine, benzidine, phenylenediamine, N,N'-di-sec-butylphenylenediamine, β-naphthylamine, α-naphthylamine, morpholine, piperazine, methanediamine, cyclopentylamine, ethylenediamine, hexamethylenetetramine, octamethylenediamine, and N,N'-dibutylphenylenediamine.

[0036] Third phosphorus-containing component In one approach, the third phosphorus-containing component of the lubricating compositions herein is an amine- and phosphorus-containing component in the form of a reaction product made by reacting a dialkyl phosphorodithioic acid, such as an O,O-dihydrocarbyl phosphorodithioic acid, with an epoxide to produce a first reaction product. This first reaction product is then reacted with phosphorus pentoxide to provide a second reaction product. The second reaction product is then neutralized with an amine compound to provide the third phosphorus-containing component of the lubricants herein.

[0037] In an approach or embodiment, a wide variety of phosphorodithioic acids may be used to form the third phosphorus-containing component. In an approach, the starting phosphorodithioic acid for producing the third phosphorus product may have the general structure of Formula III:

[0038] [ka] wherein R8 and R9 in Formula III can be C1-C30 hydrocarbyl groups, preferably linear or branched alkyl groups such as butyl, lauryl, or 4-methyl-2-pentyl groups. The starting acid of Formula III can be prepared by reacting phosphorus pentasulfide with a suitable alcohol or phenol. In one example, the alcohol or phenol can be reacted with phosphorus pentasulfide at about 50°C to about 200°C.

[0039] In embodiments, suitable epoxides used to form the first reaction product include those of Formula IV:

[0040] [ka] wherein R in formula IV 10 , R 11 , R 12 , and R 13 are each independently hydrogen or any C1 to C 30 Hydrocarbyl groups may preferably include ethylene oxide, propylene oxide, styrene oxide, α-methylstyrene oxide, combinations thereof, and similar oxides. Preferred oxides include ethylene and / or propylene oxide.

[0041] In some approaches, suitable amine compounds for neutralizing the second reaction product include aliphatic amines, aromatic amines, cycloaliphatic amines, heterocyclic amines, carbocyclic amines, or combinations thereof. In embodiments, the amines may have 4 to 30 carbon atoms. The amines may, in some approaches, include aliphatic primary amines containing at least about 8 carbon atoms, and may be represented by the structure R 14 NH2, where R 14is an aliphatic group such as, for example, tert-octyl, tert-dodecyl, tert-tetradecyl, tert-octadecyl, cetyl, behenyl, stearyl, eicosyl, docosyl, tetracosyl, hexatriacontanyl, and pentahexacontanyl. In other embodiments, suitable amines can be tertiary aliphatic primary amines, such as C11-C20 tertiary alkyl primary amines, more preferably C11-C14 tertiary alkyl primary amines. Additional amines may include, but are not limited to, cyclohexylamine, n-hexylamine, dodecylamine, di-dodecylamine, tri-dodecylamine, N-methyl-octylamine, butylamine, oleylamine, myristylamine, N-dodecyltrimethylenediamine, aniline, o-toluidine, benzidine, phenylenediamine, N,N'-di-sec-butylphenylenediamine, β-naphthylamine, α-naphthylamine, morpholine, piperazine, methanediamine, cyclopentylamine, ethylenediamine, hexamethylenetetramine, octamethylenediamine, and N,N'-dibutylphenylenediamine. In one approach, the third phosphorus compound herein may provide the lubricating compositions herein with about 0.1 to about 0.3 wt % (in another approach, about 0.1 to about 0.2 wt %) of the amine compound.

[0042] In another optional approach, hydroxy-substituted amines may also be used in the neutralization of the second reaction product. Exemplary hydroxyl-substituted amines may include ethanolamine, diethanolamine, triethanolamine, isopropanolamine, para-aminophenol, 4-amino-naphthol-1,8-amino-naphthol-1, β-aminoalizarin, 2-amino-2-ethyl-1,3-propanediol, 4-amino-4′-hydroxy-diphenyl ether, 2-amino-resorcinol, N-4-hydroxybutyl-dodecylamine, N-2-hydroxyethyl-n-octylamine, N-2-hydroxypropyldinonylamine, N,N-di-(3-hydroxypropyl)-tert-dodecylamine, N-hydroxytriethoxyethyl-tert-tetradecylamine, N-2-hydroxyethyl-tert-dodecylamine, N-hydroxyhexapropoxypropyl-tert-octadecylamine, and N-5-hydroxypentyldi-n-decylamine.

[0043] Hydrocarbylamine Compounds The first phosphorus-containing component in the form of a phosphonic acid monoester may drop out of solution or form a small amount of precipitate. If necessary, a limited amount of additional hydrocarbyl amine compound is further added to the lubricating composition herein. Such hydrocarbyl amine compound preferably includes a linear aliphatic tertiary amine.

[0044] In embodiments or approaches herein, the lubricating combination contains less than about 0.1 wt. % of a hydrocarbyl amine compound (preferably, about 0.099 wt. % or less, more preferably, about 0.098 wt. % or less), and any additive concentrate contains less than about 10 wt. % of a hydrocarbyl amine compound. Exemplary hydrocarbyl amine compounds include dihydrocarbyl (mono)thiophosphate amines, which may include those having hydrocarbyl moieties that are saturated or unsaturated groups, alkyl groups, alkenyl groups, and / or aromatic hydrocarbon groups of 2 to 24 carbon atoms. In another approach, suitable hydrocarbyl amine compounds may be primary hydrocarbyl amines containing 4 to 30 carbon atoms. Fatty amines may also be used, including alkyl amines such as n-hexylamine, n-octylamine, n-decylamine, n-dodecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-octadecylamine (stearylamine), and the like. In yet another approach, the hydrocarbyl amine may be derived from a tertiary-aliphatic primary amine having 4 to 30 carbon atoms in the alkyl group. Mixtures of amines may also be beneficial, such as a mixture of C11-C14 tertiary alkyl primary amines and / or a mixture of C18-C22 tertiary alkyl primary amines.

[0045] Thus, the lubricating compositions herein contain a total amount of amine compounds provided from three sources, including a hydrocarbyl amine compound, an amine compound provided by the second phosphorus-containing component, and then an amine compound provided by the third phosphorus-containing component. In another approach or embodiment, the lubricating compositions herein contain from about 0.1 to about 0.5 wt. % of an amine compound provided from a combination of the second amine-containing phosphorus component, the third amine-containing phosphorus component, and the hydrocarbyl amine compound. Total In yet another approach, the lubricating compositions herein include amine compounds. The total of the above The amine compound is provided by a hydrocarbyl amine compound. The total of the above About 15 to about 25 wt. % of the amine compound (in other approaches, about 18 to about 22 wt. %) is provided by the second phosphorus-containing component. The total of the above More than 50 wt. % of an amine compound (in other approaches, about 50 to about 60 wt. %) and a third phosphorus-containing component The total of the above It contains about 20 to about 30% by weight of an amine compound (in other approaches, about 25 to about 30% by weight).

[0046] Without wishing to be limited by theory, it is believed that a certain portion of the amine contributed by the second and third phosphorus-containing components can help solubilize the first phosphorus-containing component, but such amount is not sufficient to keep the first phosphorus-containing component in solution. As shown in the examples below, less than 0.1 wt. % of the additional hydrocarbyl amine compound combines with at least a portion of the amine compounds from the first and second phosphorus-containing components to keep the first phosphorus-containing component in solution.

[0047] In a further embodiment, the first phosphorus-containing component, preferably a hydrocarbyl phosphonic acid monoester, Total The weight ratio of the amine compounds (e.g., the amine compounds from the hydrocarbyl amine, the amine compounds from the second phosphorus-containing component, and the amine compounds from the third phosphorus-containing component) is from about 0.7:1 to about 1.8:1, and in other approaches, from about 1:1 to about 1.5:1.

[0048] Certain other phosphorus-based friction modifiers The lubricating compositions herein may also be free or substantially free of certain other phosphorus-based friction modifiers. While not wishing to be limited by theory, it is believed that phosphonic acid diesters, such as dialkyl hydrocarbyl phosphonates (and particularly dimethyloctadecyl phosphonate), may adversely affect copper corrosion. For example, it is believed that such phosphonic acid diesters may react or interact with the thiadiazole additives of the compositions herein, resulting in undesirable reaction products or other impurities that may degrade copper corrosion. To this end, the lubricating compositions herein may, in some approaches or embodiments, be free or substantially free (e.g., less than about 0.8 wt. %, less than 0.5 wt. %, less than about 0.25 wt. %, less than about 0.1 wt. %) of phosphonic acid diesters, or may contain no functional amounts of phosphonic acid diesters.

[0049] Thiadiazole Additives The lubricating compositions herein may also include a thiadiazole or a derivative thereof. In some approaches, the lubricating compositions may include about 0.1 wt. % or more of a thiadiazole or a derivative thereof. In some approaches, the lubricating compositions may include about 0.1 wt. % to about 1 wt. %, or about 0.1 wt. % to about 0.5 wt. % of a thiadiazole or a derivative thereof. In some embodiments, the thiadiazole or a derivative thereof may be a mixture of thiadiazole compounds and / or hydrocarbyl-substituted derivatives thereof.

[0050] In some approaches, the thiadiazole or derivative thereof provides at least about 350 ppm of sulfur to the lubricating composition, and in other approaches, at least about 380 ppm of sulfur, at least about 400 ppm of sulfur, at least about 500 ppm of sulfur, at least about 600 ppm of sulfur, at least about 700 ppm of sulfur up to about 2500 ppm of sulfur, at least about 2000 ppm of sulfur, at least about 1500 ppm of sulfur, or at least about 1000 ppm of sulfur.

[0051] In this approach, the thiadiazole or derivative thereof comprises one or more compounds having the structure of Formula I:

[0052] [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, where 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:

[0053] [ka] In formula Ia, each integer n is 1, each R3 is sulfur, and each R4 is a C5 to C15 alkyl group, preferably a C8 to C12 alkyl group;

[0054] [ka] In Formula Ib, one integer n is 1, the associated R group is a C5-C15 alkyl group (preferably a C8-C12 alkyl group), the associated R group is sulfur, and the other integer n is 0, the associated R group is hydrogen. In some embodiments, the thiadiazole or derivative thereof comprises a blend of Formulas Ia and Ib, with Formula Ia being the majority of the blend; in another approach, 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%).

[0055] In another approach or embodiment, examples of thiadiazole compounds 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, e.g., 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, which are incorporated herein by reference.

[0056] base oil In one approach, suitable base oils for use in the lubricating compositions or gear fluids herein include mineral oils, synthetic oils, and all common mineral oil base stocks. Mineral oils can be naphthenic or paraffinic. Mineral oils can be refined by conventional methods using acids, alkalis, and other agents such as clay or aluminum chloride, or can be extracted oils produced by solvent extraction using solvents such as phenol, sulfur dioxide, furfural, or dichlorodiethyl ether. Mineral oils can be hydrotreated or hydrofinished, dewaxed by a cooling or catalytic dewaxing process, or hydrocracked (such as the Yubase® family of hydrocracked base oils from SK Innovation Co., Ltd. (Seoul, Korea)). Mineral oils can be produced from natural crude oil sources or composed of isomerized wax materials or residues from other refining processes.

[0057] The base oil, or base oils of lubricating viscosity used in the compositions herein, can be selected from any base oil suitable for driveline or gear oil applications. Examples include base oils in Groups I through V, as designated by the American Petroleum Institute (API) Base Oil Interchangeability Guidelines. These three base oil groups are as follows:

[0058] [Table 1]

[0059] Groups I, II, and III are mineral oil process stocks and may be preferred for the driveline or gear fluids of this application. It should be noted that although Group III base oils are derived from mineral oils, the rigorous processing these fluids undergo results in their physical properties being very similar to some true synthetic oils, such as PAOs. Therefore, 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. In some approaches, the base oil may be a blend of Group I and Group II oils, which may be about 0% to about 100% Group I oil, about 0% to about 100% Group II oil, about 0% to about 100% Group III oil, or various blends of Group I and II, Group I and III, or Group II and III oil blends.

[0060] 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.

[0061] 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.

[0062] 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 paraffinic-naphthenic types. Such oils may be partially or fully hydrogenated, if desired. Oils derived from coal or shale may also be useful.

[0063] The major amount of base oil included in the gear fluids herein may be selected from the group consisting of Group I, Group II, Group III, and combinations of two or more of the foregoing, where the major amount of base oil is other than the base oil resulting from the provision of additive components or viscosity index improvers in the composition. In another embodiment, the major amount of base oil included in the lubricating composition may be selected from the group consisting of Group I, Group II, and combinations of two or more of the foregoing, where the major amount of base oil is other than the base oil resulting from the provision of additive components or viscosity index improvers in the composition.

[0064] The base oil can also be any of the synthetic base oils. Useful synthetic lubricating oils can 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.

[0065] 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.

[0066] The amount of base oil of lubricating viscosity in the compositions herein can be the remainder remaining after subtracting the total amount of performance additives from 100% by weight. For example, the oil of lubricating viscosity can be present in the final fluid in a "major amount," such as greater than about 50%, greater than about 60%, greater than about 70%, greater than about 80%, greater than about 85%, greater than about 90%, or greater than 95% by weight.

[0067] In some approaches, preferred base oils or base oils of lubricating viscosity have less than about 25 ppm sulfur, a viscosity index greater than about 120 ppm, and a kinematic viscosity at about 100°C of about 2 to about 8 cSt. In other approaches, base oils of lubricating viscosity have less than about 25 ppm sulfur, a viscosity index greater than 120, and a kinematic viscosity at 100°C of about 4 cSt. The base oil may have a CP (paraffinic carbon content) greater than 40%, greater than 45%, greater than 50%, greater than 55%, or greater than 90%. The base oil may have a CA (aromatic carbon content) less than 5%, less than 3%, or less than 1%. The base oil may have a CN (naphthenic carbon content) less than 60%, less than 55%, less than 50%, or less than 50%, and greater than 30%. The base oil may have a ratio of 1-ring naphthenes to 2-ring naphthenes to 6-ring naphthenes less than 2, less than 1.5, or less than 1.

[0068] Suitable driveline or gear lubricant compositions herein may contain additive components in the ranges listed in Table 2 below.

[0069] [Table 2]

[0070] The percentages of each component above represent the weight percent of each component, based on the total weight of the final additive or lubricating oil composition. The remainder of the lubricating oil composition consists of one or more base oils or solvents. The additives used in formulating the compositions described herein can be blended into the base oil or solvent individually or in various subcombinations. 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).

[0071] The lubricating compositions described herein can be formulated to provide lubrication, improved friction performance characteristics, and improved copper corrosion resistance for various applications. The driveline lubricating compositions described herein can be used to lubricate machine components such as gears. The lubricating fluids according to the present disclosure can be used in gear applications such as industrial gear applications, automotive gear applications, axles, and stationary gearboxes. Gear types can 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 step automatic transmissions, continuously variable transmissions, semi-automatic transmissions, automated manual transmissions, toroidal transmissions, and dual-clutch transmissions. The driveline lubricating compositions herein are particularly suitable for use in axles, transfer cases, differentials, such as straight differentials, rotary differentials, limited slip differentials, clutch-type differentials, and locking differentials.

[0072] Optional Additives 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.

[0073] Other phosphorus-containing compounds 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 15 wt. %, or from about 0.01 wt. % to about 10 wt. %, or from about 0.05 wt. % to about 5 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 5000 ppm phosphorus, or from about 50 to about 5000 ppm phosphorus, or from about 300 to about 1500 ppm phosphorus, or up to 600 ppm phosphorus, or up to 900 ppm phosphorus.

[0074] 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.

[0075] 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.

[0076] In any of the above phosphorus-containing compounds, the compound can have from about 5% to about 20% by weight phosphorus, or from about 5% to about 15% by weight phosphorus, or from about 8% to about 16% by weight phosphorus, or from about 6% to about 9% by weight phosphorus.

[0077] When a phosphorus-containing compound is included in a lubricant composition in combination with the dispersants described above, it unexpectedly imparts positive friction characteristics, such as a low coefficient of friction, to the lubricant composition. The benefits of the present invention are even more pronounced in some cases where the phosphorus-containing compound alone imparts negative friction characteristics to the fluid. When these phosphorus-containing compounds, which have relatively poor friction reduction properties, are combined with the olefin copolymer dispersants described herein, the lubricant composition has an improved, i.e., lower, coefficient of friction. That is, the dispersants herein tend to convert fluids containing phosphorus-containing compounds with relatively poor coefficients of friction into fluids with improved friction properties.

[0078] This improvement in the frictional properties of lubricating compositions comprising a phosphorus-containing compound and the olefin copolymer dispersants described herein is surprising because the frictional properties of the fluid are improved over combinations of a phosphorus-containing compound and other types of dispersants, including polyisobutylene succinimide dispersants and olefin copolymer succinimide dispersants, which do not have the specified properties of the copolymers described above.

[0079] Another type of phosphorus-containing compound that, when combined with the olefin copolymer dispersants herein, imparts improved frictional properties to lubricating compositions is the ashless (metal-free) phosphorus-containing compound.

[0080] 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.

[0081] The ashless phosphorus-containing compound may have the formula:

[0082] [ka] In Formula XIV, 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 straight alkyl chain; and R" is a C1-C18 hydrocarbyl chain. When the phosphorus-containing compound has the structure shown in Formula XIV, the compound can have from about 8% to about 16% by weight of phosphorus.

[0083] 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 80 to 900 ppm of phosphorus to the lubricant composition.

[0084] In another embodiment, the lubricant composition comprises 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 80 to 1500 ppm of phosphorus to the lubricant composition.

[0085] In yet another embodiment, the lubricant composition comprises 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 80 to 1550 ppm of phosphorus to the lubricant composition.

[0086] 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 C18, and the one or more phosphorus-containing compounds are present in an amount providing 80 to 850 ppm of phosphorus to the lubricant composition.

[0087] In some embodiments, the phosphorus-containing compound has the structure shown in Formula XIV and provides from about 80 to about 4500 ppm of phosphorus to the lubricant composition. In other embodiments, the phosphorus-containing compound is present in an amount to provide from about 150 to about 1500 ppm of phosphorus, or from about 300 to about 900 ppm of phosphorus, or from about 800 to 1600 ppm of phosphorus, or from about 900 to about 1800 ppm of phosphorus to the lubricant composition.

[0088] Other anti-wear agents 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 wt. % to about 15 wt. %, or from about 0.01 wt. % to about 10 wt. %, or from about 0.05 wt. % to about 5 wt. %, or from about 0.1 wt. % to about 3 wt. % of the lubricating oil composition.

[0089] Other extreme pressure agents The lubricant compositions of this disclosure may also contain other extreme pressure agents, so long as the lubricant compositions herein contain the described amounts and profiles described herein. The optional extreme pressure agent may contain sulfur, and may contain at least 12 weight percent sulfur. In some embodiments, the extreme pressure agent added to the lubricating oil is sufficient to provide the lubricant composition with at least 350 ppm sulfur, 500 ppm sulfur, 760 ppm sulfur, about 350 to about 2,000 ppm sulfur, about 2,000 to about 30,000 ppm sulfur, or about 2,000 to about 4,800 ppm sulfur, or about 4,000 to about 25,000 ppm sulfur.

[0090] 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). Other suitable examples include sulfurized olefins, sulfur-containing aminoheterocyclic compounds, 5-dimercapto-1,3,4-thiadiazoles, polysulfides having a majority of S3 and S4 sulfides, sulfurized fatty acids, sulfurized branched-chain olefins, organic polysulfides, and mixtures thereof.

[0091] In some embodiments, the extreme pressure agent is present in the lubricating composition in an amount 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 from about 0.05 wt % to about 0.5 wt %, based on the total weight of the lubricant composition. In other embodiments, the extreme pressure agent is present in an amount from about 0.1 wt % to about 3.0 wt %, based on the total weight of the lubricant composition. In other embodiments, the extreme pressure agent is present in an amount from about 0.6 wt % to about 1 wt %, based on the total weight of the lubricant composition. In yet other embodiments, the detergent is present in an amount of about 1.0 wt %, based on the total weight of the lubricant composition.

[0092] One suitable class of extreme pressure agents are polysulfides composed of one or more compounds represented by the formula: Ra-Sx-Rb, where Ra and Rb are hydrocarbyl groups, each of which may contain 1 to 18, or in other approaches, 3 to 18, carbon atoms; x may range from 2 to 8, typically from 2 to 5, and particularly 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 a wide variety of 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) may be used. Examples of other useful dihydrocarbyl polysulfides include diamyl polysulfide, dinonyl polysulfide, didodecyl polysulfide, and dibenzyl polysulfide.

[0093] Another suitable class of extreme pressure agents is sulfurized isobutene, which is prepared 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.

[0094] 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.

[0095] antioxidants 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.

[0096] 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.

[0097] Useful antioxidants may include diarylamines and phenols. In one embodiment, the lubricating oil composition may contain a mixture of diarylamines and phenols, with each antioxidant present in an amount sufficient to provide up to about 5 wt. % antioxidant, based on the weight of the lubricant composition. In one embodiment, the antioxidant may be a mixture of about 0.3 wt. % to about 1.5 wt. % diarylamines and about 0.4 wt. % to about 2.5 wt. % phenols, based on the weight of the lubricant composition.

[0098] Examples of suitable olefins that can be sulfurized to form sulfurized olefins include propylene, butylene, isobutylene, polyisobutylene, pentene, hexene, heptene, octene, nonene, decene, undecene, dodecene, tridecene, tetradecene, pentadecene, hexadecene, heptadecene, octadecene, nonadecene, eicosene, or mixtures thereof. In one embodiment, hexadecene, heptadecene, octadecene, nonadecene, eicosene, or mixtures thereof, as well as their dimers, trimers, and tetramers, are particularly useful olefins. Alternatively, the olefin can be a Diels-Alder adduct of a diene, such as 1,3-butadiene, and an unsaturated ester, such as butyl acrylate.

[0099] Another class of sulfurized olefins includes sulfurized fatty acids and their esters. The fatty acids are often derived from vegetable or animal oils and typically contain from about 4 to about 22 carbon atoms. Examples of suitable fatty acids and their esters include triglycerides, oleic acid, linoleic acid, palmitoleic acid, or mixtures thereof. Often, the fatty acids are derived from lard oil, tall oil, peanut oil, soybean oil, cottonseed oil, sunflower seed oil, or mixtures thereof. The fatty acids and / or esters may be mixed with an olefin, such as an α-olefin.

[0100] The one or more antioxidants may be present in the range of from about 0% to about 20%, or from about 0.1% to about 10%, or from about 1% to about 5% by weight of the lubricating oil composition.

[0101] Dispersants Dispersants contained in the lubricant composition may include, but are not limited to, an oil-soluble polymeric hydrocarbon backbone having functional groups capable of associating with particles to be dispersed. Typically, dispersants contain amine, alcohol, amide, or ester polar moieties attached to the polymer backbone, often through a bridging group. Dispersants may be selected from Mannich dispersants such as those described in U.S. Pat. Nos. 3,634,515, 3,697,574, and 3,736,357; ashless succinimide dispersants such as those described in U.S. Pat. Nos. 4,234,435 and 4,636,322; amine dispersants such as those described in U.S. Pat. Nos. 3,219,666, 3,565,804, and 5,633,326; Koch dispersants such as those described in U.S. Pat. Nos. 5,936,041, 5,643,859, and 5,627,259; and polyalkylene succinimide dispersants such as those described in U.S. Pat. Nos. 5,851,965, 5,853,434, and 5,792,729.

[0102] In some embodiments, the additional dispersant may be derived from polyalphaolefin (PAO), succinic anhydride, olefin maleic anhydride copolymer. As an example, the additional dispersant may be described as poly-PIBSA. In another embodiment, the additional dispersant may be derived from an anhydride grafted onto an ethylene-propylene copolymer. Another additional dispersant may be a high molecular weight ester or half-ester amide.

[0103] When present, the additional dispersant can be used in an amount sufficient to provide up to about 10% by weight, based on the final weight of the lubricating oil composition. Alternative amounts of dispersant that can be used can be from about 0.1% to about 10% by weight, or from about 0.1% to about 10% by weight, or from about 3% to about 8% by weight, or from about 1% to about 6% by weight, based on the final weight of the lubricating oil composition.

[0104] Viscosity Index Improver 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 of which are described in U.S. Patent Application Publication No. 20120101017(A1), which is incorporated herein by reference.

[0105] The lubricating oil compositions herein may also optionally contain one or more dispersant viscosity index improvers in addition to or instead 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.

[0106] The total amount of viscosity index improver and / or dispersant viscosity index improver can be from about 0% to about 20%, from about 0.1% to about 15%, from about 0.1% to about 12%, or from about 0.5% to about 10%, from about 3% to about 20%, from about 3% to about 15%, from about 5% to about 15%, or from about 5% to about 10% by weight of the lubricating oil composition.

[0107] 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.

[0108] Other optional additives 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 performance additives.

[0109] 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.

[0110] Suitable suds suppressors include silicon-based compounds such as siloxanes.

[0111] 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.

[0112] 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 is free of rust inhibitors.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] As used herein, 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 and / or limited slip differentials and / or wet brakes, wet clutches, transmissions, and gear drive components having metal-to-metal contact.

[0118] As used herein, the term "hydrocarbyl substituent" or "hydrocarbyl group" is used in its ordinary sense and is 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.

[0119] As used herein, the term "weight percent" or "wt. %" means the percentage of the listed component expressed relative to the weight of the entire composition, unless otherwise specified. All percentages herein are by weight unless otherwise specified.

[0120] 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.

[0121] 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.

[0122] As used herein, molecular weight is measured by gel permeation chromatography (GPC) using commercially available polystyrene standards (having 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 PLgel 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 wt.%, 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.

[0123] As used herein, the distribution, amount, or ratio of sulfur moieties in organic sulfide compounds was determined using C NMR on a Bruker Avance-3 HD 500 MHz instrument equipped with a 5 mm BBO Prodigy probe (or equivalent). Samples were dissolved in chloroform-d and1 Approximately 3% (wt / wt) for H NMR one-dimensional (1D) and two-dimensional (2D) homonuclear experiments, 13 For C 1D and 2D heteronuclear experiments, the concentration was approximately 30% (wt / wt). Chloroform-d was used as the chemical shift standard, and d H = 7.27 and d C =77.0 ppm. The experiment was carried out at ambient temperature. Direct observation 1D 1 H and 13 C- 1 The H decoupling experiment was performed with a 90° pulse width, 5 × T delay, and 13 Gates for C NMR experiments 1 H decoupling was used and run under quantitative conditions. In addition, distortionless enhancement by polarization transfer (DEPT) experiments using the 135° pulse option were also obtained. 2D experiments used to assist in structure assignment included homonuclear correlation spectroscopy (COSY), heteronuclear single quantum coherence (HSQC), and heteronuclear multiple bond correlation spectroscopy (HMBC). All NMR data were acquired using Bruker Topspin 3.62 software from Bruker Inc. (Billerica, MA) and processed using ACD / Spectrus Processor 2021.1.3 software from Advanced Chemistry Development, Inc. using standard parameters (or equivalent equipment / software).

[0124] 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. [Example]

[0125] 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. Any reference to a standardized test method herein refers to the version of the test method publicly available at the time of this disclosure, unless otherwise clear from the context of its use in the specification, claims, or these examples. [Example]

[0126] An exemplary organic polysulfide reaction product can be prepared as follows: A 300 mL stainless steel autoclave was charged with sulfur (67.2 g, 1.92 gram atoms) and 0.1 mL of n-butylamine (1.0 mmol). The autoclave was cooled in a dry ice isopropyl alcohol bath and sparged with N2 (4 x 100 psi). Isobutylene (58.8 g, 1.05 moles) was condensed into the autoclave. The autoclave was sealed and heated to 140°C under an autogenous pressure of 550 psi for 26.5 hours. After standing overnight, the autoclave was vented to a caustic trap, the condenser was cooled in dry ice, and then heated to 10°C and sparged with N2 for 0.5 hours.

[0127] A 100 mL round-bottom flask equipped with an overhead stirrer and reflux condenser was then charged with sodium hydrogen sulfide (10.8 g, 46% aqueous solution) and sodium hydroxide (12.0 g, 50% aqueous solution), and the sulfurized product prepared in Example 3A (20 g). The solution was vigorously stirred and heated at 80° C. for 2 hours and 100° C. for 2 hours. After cooling, the solution was taken up in diethyl ether and poured into a separatory funnel.

[0128] Two organic sulfide reaction products consistent with those described above were prepared, with the amount of caustic (sodium hydroxide) being varied as needed to form each of the reaction products.

[0129] Organic sulfide reaction product A: The first organic sulfide reaction product had about 15 wt. % compounds having S2 moieties, about 82 wt. % compounds having S3 moieties, about 3 wt. % compounds having S4 moieties, and no compounds having either S5 or S6 moieties. Reaction product A had a weight ratio of S3 to S4 of about 27.3:1. The sulfide profile was determined by C NMR as described above.

[0130] Organic sulfide reaction product B: The second organic sulfide reaction product had about 15 wt% compounds with S2 moieties, about 59 wt% compounds with S3 moieties, about 24 wt% compounds with S4 moieties, about 3 wt% compounds with S5 moieties, and no compounds with S6 moieties. Reaction product B had a weight ratio of S3 to S4 of about 2.5:1. The sulfide profile was also determined by C NMR as described above. [Example]

[0131] The organic sulfide reaction products A and B of Example 1 were evaluated in combination with various phosphorus-containing components and amine compounds in the lubricating compositions of Table 3. The lubricating compositions of Table 3 contained, in addition to the additives listed in the table, about 0.13 wt. % of a thiadiazole or its derivative. The lubricating compositions also contained the same additive package, including the same detergent, friction modifier, viscosity modifier, antioxidant, rust inhibitor, corrosion inhibitor, seal swell agent, and antifoam agent. All of the evaluated compositions also contained the balance of base oil and / or process oil necessary to achieve a target KV100 viscosity of about 13 cSt to 14 cSt.

[0132] The second phosphorus-containing component in Table 3 was an amine salt of dibutyl hydrogen thiophosphite. The third phosphorus-containing component in Table 3 was a phosphorus-based reaction product formed by (i) reacting O,O-di(4-methyl-2-pentyl)phosphorodithioic acid with propylene oxide to form a first reaction product, (ii) reacting the first reaction product with phosphorus pentoxide to produce an acidic phosphate intermediate, and (iii) neutralizing at least a majority of the intermediate with a C11-C14 tertiary alkyl primary amine. The hydrocarbyl amine compound was an aliphatic tertiary primary amine.

[0133] [Table 3] * The amount of sulfur is calculated from each component. **The sulfur profile was determined by C NMR and reflects the t-butyl isomer, although other isomers present have similar profiles and ratios. *** the total amount of amine compound provided by the second and third phosphorus-containing components

[0134] Copper corrosion was evaluated using ASTM D130, with passing performance being a 1A or 1B visual observation (3 hours at 121°C) as described in the test method. Test results are provided in Table 4 below.

[0135] [Table 4] ** Passing performance is 1A or 1B.

[0136] Only the lubricating composition of Inventive Fluid 1, which has the unique mixture of sulfur compounds provided by both organic sulfide reaction products A and B, passed both the extreme pressure test and the copper corrosion test when combined with a balanced combination of three phosphorus-containing components and an additional hydrocarbyl amine compound that simultaneously maintained methyl octadecyl phosphonate in solution.

[0137] 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.

[0138] 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.

[0139] 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.

[0140] 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.

[0141] 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.

[0142] 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.

[0143] 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 comprising: one or more base oils of lubricating viscosity, an extreme pressure agent containing more than 1.5 wt. % to 3 wt. % sulfur based on the lubricating composition; a first phosphorus-containing component comprising a hydrocarbyl phosphonic acid monoester; a second phosphorus-containing component comprising an amine salt of a dialkyl hydrogen thiophosphite; a third phosphorus-containing component prepared by reacting a dialkyl phosphorodithioic acid with ethylene oxide and / or propylene oxide to provide a first reaction product, further reacting the first reaction product with phosphorus pentoxide to provide a second reaction product, and neutralizing the second reaction product with one or more aliphatic primary amines to provide the third phosphorus-containing component; a thiadiazole selected from a monohydrocarbylthiol-substituted thiadiazole, a bishydrocarbylthiol-substituted thiadiazole, or a combination thereof; and less than 0.1 wt. % of a hydrocarbyl amine compound; the total amine compound content of the second phosphorus-containing component, the third phosphorus-containing component, and the hydrocarbyl amine compound in the lubricating composition is 0.1 to 0.5 wt. %; and 15 to 25 weight percent of the total amine compounds are the hydrocarbyl amine compound, greater than 50 weight percent of the total amine compounds are the second phosphorus-containing component, and 20 to 30 weight percent of the total amine compounds are the third phosphorus-containing component.

2. 2. The lubricating composition of claim 1, wherein the first reaction product is prepared by reacting O,O'-di(4-methyl-2-pentanyl)phosphorodithioic acid with ethylene and / or propylene oxide.

3. 2. The lubricating composition of claim 1, wherein the weight ratio of said hydrocarbyl phosphonic acid monoester to said total amine compounds is from 0.7:1 to 1.8:

1.

4. The lubricating composition comprises 1.3 to 3 wt. % total sulfur, at least 90 wt. % of the total sulfur provided by the extreme pressure agent, a blend of organic sulfide compounds, the blend comprising S ２ 10-15% by weight of an organic sulfide compound having a sulfur moiety, S ３ 60-70% by weight of an organic sulfide compound having a sulfur moiety, and S ４ 10. The lubricating composition of claim 1 having 12 to 20 wt. % of an organic sulfurized compound having a sulfur moiety.

5. 5. The lubricating composition of claim 4, wherein the blend of organosulfide compounds comprises a first organosulfide compound and a second organosulfide compound different from the first organosulfide compound.

6. 6. The lubricating composition of claim 5, wherein the lubricating composition comprises 1.5 to 2.8 wt. % of the first organic sulfurized compound and 1.5 to 2.8 wt. % of the second organic sulfurized compound.

7. 6. The lubricating composition of claim 5, wherein the lubricating composition comprises a weight ratio of the first organic sulfurized compound to the second organic sulfurized compound of from 0.8:1 to 1:0.

8.

8. Each organic sulfide compound in the blend independently has the formula R １ -S ｘ -R ２ wherein R １ and R ２ 5. The lubricating composition of claim 4, wherein is independently selected from propyl, isopropyl, butyl, isobutyl, tert-butyl, or combinations thereof; and x is an integer from 2 to 6.

9. 2. The lubricating composition of claim 1, wherein the hydrocarbyl amine compound is a tertiary-aliphatic primary amine having 4 to 20 carbon atoms in the alkyl group.

10. 2. The lubricating composition of claim 1, wherein the hydrocarbyl amine compound is selected from one or more of tertiary butylamine, tertiary hexyl primary amine, 1-methyl-1-amino-cyclohexane, tertiary octyl primary amine, tertiary decyl primary amine, tertiary dodecyl primary amine, tertiary tetradecyl primary amine, tertiary hexadecyl primary amine, tertiary octadecyl primary amine, tertiary tetracosanyl primary amine, tertiary octacosanyl primary amine, tertiary oleylamine, or combinations thereof.

11. (a) the hydrocarbyl phosphonic acid monoester has the structure of Formula II: 【Chemistry 1】 In the formula, R ５ is C １２ ~C ３０ is a hydrocarbyl group, R ６ is a C1-C4 alkyl group, R' is hydrogen or an alkyl group, and / or (b) The lubricating composition of claim 1, wherein the lubricating composition comprises from 0.1 wt % to 0.8 wt % of the hydrocarbyl phosphonic acid monoester.

12. (a) the thiadiazole is 1,3,4-thiadiazole; (b) the lubricating composition comprises 1 wt. % or less of the thiadiazole; and / or (c) the thiadiazole comprises one or more compounds having the structure of Formula I: 【Chemistry 2】 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 said n in the moiety is 1; At least one R ３ 10. The lubricating composition of claim 1, wherein is sulfur.

13. 10. The lubricating composition of claim 1, wherein the second phosphorus-containing component is an amine salt of dibutyl hydrogen thiophosphate.

14. 10. The lubricating composition of claim 1, wherein the one or more aliphatic primary amines comprise a tertiary aliphatic primary amine.

15. 10. A method of lubricating gears, differentials, and / or wet brakes with the lubricating composition of claim 1, wherein the lubricating composition is provided from a common fluid reservoir, tank, and / or sump.

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