Melamine-based compounds for lubricating compositions

Abstract

In one embodiment, melamine-based compounds are suitable as corrosion inhibitors for lubricating compositions, particularly for transmission fluids (manual, automatic, dual clutch or electric), shaft fluids, differential fluids, tractor fluids, industrial gear fluids, and / or lubricating fluids for other gear-type applications. The melamine-based compound is in the form of an oil-soluble hydrocarbyl-substituted melamine derivative that includes the reaction product of the reaction of a hydrocarbyl-substituted succinic anhydride with melamine under conditions effective to form a hydrocarbyl-substituted melamine polycarboxylic acid or anhydride compound.

Description

Technical Field

[0001] The present disclosure relates to melamine-based compounds suitable for use as lubricant additives, particularly melamine-based compounds suitable as corrosion inhibitors, and to lubricating compositions comprising such melamine-based compounds for achieving improved copper corrosion performance. Background Art

[0002] Transmissions (manual, automatic, dual clutch, and / or electric), axles, differentials, and / or industrial gears typically require lubricants that provide specific performance characteristics suitable for the desired application. Generally, lubricants for such applications may need, for example, the fluid to meet one or more performance characteristics such as extreme pressure, anti-wear, friction, and / or copper corrosion, to suggest some common requirements for such fluids. Various additives may be included in the lubricant to achieve the performance. For example, such lubricants typically include oil-soluble copper corrosion inhibitors such as triazoles to protect metals (such as copper) from corrosion.

[0003] Methylbenzotriazole (e.g., methyl-substituted benzotriazole) is a common copper corrosion inhibitor that provides good copper corrosion performance to transmission fluids, axle fluids, differential fluids, tractor fluids, and / or industrial gear fluids, to suggest some applications that typically include methylbenzotriazole. Copper corrosion can be evaluated by extending the test to 168 hours at 150 °C according to ASTM D130 and / or a more extreme version of ASTM D130. Copper corrosion is measured by visual dullness rating and / or by the amount of copper leaching in the lubricant. While effective corrosion inhibition can be provided in such fluids and methylbenzotriazole has little dulling and low levels of copper leaching, for various reasons, the use of methylbenzotriazole may be undesirable. It is challenging to find an alternative copper corrosion inhibitor that provides performance comparable to methylbenzotriazole and is compatible with lubricant formulations for transmission fluids, axle fluids, differential fluids, tractor fluids, industrial gear fluids, and / or other gear-type applications. Summary of the Invention

[0004] In one method or embodiment, a corrosion inhibitor in the form of an oil-soluble hydrocarbyl-substituted melamine derivative is described herein, and the corrosion inhibitor has a structure of Formula I in all aspects

[0005]

[0006] Each of R1, R2, and R3 is independently -NH2, a hydrocarbyl-substituted succinimide group, or a hydrocarbyl-substituted dicarboxylic acid-amide group, and one or two of R1, R2, and R3 are independently a hydrocarbyl-substituted succinimide group or a hydrocarbyl-substituted dicarboxylic acid-amide group, and the remaining R1, R2, and R3 are independently -NH2 or a substituted dicarboxylic acid-amide.

[0007] In other methods or embodiments, the corrosion inhibitors of the previous paragraph include other features or embodiments in any combination. These other features or embodiments include one or more of the following: wherein the hydrocarbyl substituent of the succinimide group or the dicarboxylic acid-amide group is a C12 to C30 hydrocarbyl group; and / or wherein the hydrocarbyl substituent of the succinimide group or the dicarboxylic acid-amide group is a C12 to C24 hydrocarbyl group; and / or wherein the corrosion inhibitor has from about 5 wt% to about 25 wt% nitrogen; and / or wherein the corrosion inhibitor is a reaction product of a hydrocarbyl-substituted succinic acid or anhydride and melamine, wherein the hydrocarbyl-substituted succinic acid or anhydride is in molar excess relative to melamine; and / or wherein the molar ratio of the hydrocarbyl-substituted succinic acid or anhydride to melamine is from about 1.1:1 to about 4:1; and / or wherein the molar ratio of the hydrocarbyl-substituted succinic acid or anhydride to melamine is from about 1.1:1 to about 3:1; and / or wherein one of R1, R2, and R3 is independently a hydrocarbyl-substituted succinimide group or a hydrocarbyl-substituted dicarboxylic acid-amine group, and the remaining two of R1, R2, and R3 are -NH2 groups; and / or wherein two of R1, R2, and R3 are independently a hydrocarbyl-substituted succinimide group or a hydrocarbyl-substituted dicarboxylic acid-amine group, and the remaining one of R1, R2, and R3 is an -NH2 group; and / or wherein the oil-soluble hydrocarbyl-substituted melamine derivative has one or more of the following structures:

[0008]

[0009] wherein each of their R groups is independently a C12 to C30 hydrocarbyl group; and / or wherein a lubricating composition containing from about 0.1 wt% to about 0.5 wt% of the corrosion inhibitor exhibits less than about 100 ppm of copper after being tested at 150 °C for 168 hours according to ASTM D130.

[0010] In another method or embodiment, a method for preparing an oil-soluble hydrocarbyl-substituted melamine derivative corrosion inhibitor is described herein. In one aspect, the method includes reacting a hydrocarbyl-substituted succinic acid or anhydride with melamine, wherein the hydrocarbyl-substituted succinic acid or anhydride is in molar excess relative to melamine.

[0011] In another method or embodiment, the method for preparing the oil-soluble hydrocarbyl-substituted melamine derivative corrosion inhibitor of the previous paragraph includes other method steps, features, or embodiments in any combination. These other steps, features, or embodiments include one or more of the following: wherein the hydrocarbyl substituent is a C12 to C30 hydrocarbyl group; and / or wherein the hydrocarbyl substituent is a C12 to C24 hydrocarbyl group; and / or wherein the molar ratio of the hydrocarbyl-substituted succinic acid or anhydride to melamine is from about 1.1:1 to about 4:1; and / or wherein the molar ratio of the hydrocarbyl-substituted succinic acid or anhydride to melamine is from about 1.1:1 to about 3:1; and / or wherein the resulting corrosion inhibitor has from about 5 wt% to about 25 wt% nitrogen; and / or wherein the reaction conditions include a temperature of from about 50°C to about 200°C (in other methods, from about 50°C to about 150°C, or from about 100°C to about 200°C) and a reaction time of from about 1 hour to about 20 hours (in other methods, from about 4 hours to about 16 hours, and in additional methods, from about 6 hours to about 12 hours), and / or wherein the resulting oil-soluble hydrocarbyl-substituted melamine derivative has the structure of Formula I

[0012]

[0013] wherein each of R1, R2, and R3 is independently -NH2, a hydrocarbyl-substituted succinimide group, or a hydrocarbyl-substituted dicarboxylic acid-amide group, and wherein one or both of R1, R2, and R3 are independently a hydrocarbyl-substituted succinimide group or a hydrocarbyl-substituted dicarboxylic acid-amide group, and the remaining of R1, R2, and R3 are independently -NH2 or a hydrocarbyl-substituted dicarboxylic acid-amide; and / or wherein one of R1, R2, and R3 is independently a hydrocarbyl-substituted succinimide group or a hydrocarbyl-substituted dicarboxylic acid-amine group, and the remaining two of R1, R2, and R3 are -NH2 groups; and / or wherein two of R1, R2, and R3 are independently a hydrocarbyl-substituted succinimide group or a hydrocarbyl-substituted dicarboxylic acid-amine group, and the remaining one of R1, R2, and R3 is an -NH2 group; and / or wherein the oil-soluble hydrocarbyl-substituted melamine derivative has one or more of the following structures:

[0014]

[0015] In another embodiment or method, the present disclosure includes a driveline lubricating composition that includes any embodiment of the corrosion inhibitor described above in the Summary of the Invention. In one aspect, the driveline lubricating composition of the present disclosure comprises one or more base oils having lubricating viscosity; an oil-soluble hydrocarbyl-substituted melamine derivative having the structure of Formula I

[0016]

[0017] Each of R1, R2, and R3 is independently -NH2, a hydrocarbyl-substituted succinimide group, or a hydrocarbyl-substituted dicarboxylic acid-amide group, and one or two of R1, R2, and R3 are independently a hydrocarbyl-substituted succinimide group or a hydrocarbyl-substituted dicarboxylic acid-amide group, and the remaining R1, R2, and R3 are independently -NH2 or a hydrocarbyl-substituted dicarboxylic acid-amide; and in some embodiments, the driveline lubricating composition is substantially free of tolyltriazole additives or derivatives thereof (as further defined herein).

[0018] In other embodiments, the lubricating composition described in the previous paragraph may include one or more other features or embodiments in any combination. These other features or embodiments may include one or more of the following: wherein the hydrocarbyl substituent of the succinimide group or the dicarboxylic acid-amide group is a C12 to C30 hydrocarbyl group; and / or wherein the oil-soluble hydrocarbyl-substituted melamine derivative is a reaction product of a hydrocarbyl-substituted succinic acid or anhydride and melamine, wherein the hydrocarbyl-substituted succinic acid or anhydride is in molar excess relative to melamine; and / or wherein the molar ratio of the hydrocarbyl-substituted succinic acid or anhydride to melamine is from about 1.1:1 to about 4:1; and / or wherein one of R1, R2, and R3 is independently a hydrocarbyl-substituted succinimide group or a hydrocarbyl-substituted dicarboxylic acid-amine group, and the remaining two of R1, R2, and R3 are -NH2 groups; and / or wherein two of R1, R2, and R3 are independently a hydrocarbyl-substituted succinimide group or a hydrocarbyl-substituted dicarboxylic acid-amine group, and the remaining one of R1, R2, and R3 is an -NH2 group; and / or wherein the oil-soluble hydrocarbyl-substituted melamine derivative has one or more of the following structures:

[0019]

[0020] wherein each of their R groups is independently a C12 to C30 hydrocarbyl group; and / or wherein the lubricating composition is free of tolyltriazole additives or derivatives thereof; and / or wherein the lubricating composition is free of water; and / or wherein the lubricating composition has a kV100 viscosity of from about 3 cSt to about 10 cSt; and / or wherein the lubricating composition has less than about 215 ppm of copper after being tested at 150 °C for 168 hours according to ASTM D130; and / or wherein the oil-soluble hydrocarbyl-substituted melamine derivative provides from about 5 ppm to about 1100 ppm of nitrogen to the lubricating composition; and / or comprises from about 0.01 wt% to about 0.5 wt% of the oil-soluble hydrocarbyl-substituted melamine derivative; and / or wherein the lubricating composition further comprises less than about 1 wt% of an alkylated diphenylamine.

[0021] In yet another method or embodiment, a method of lubricating a driveline component is described herein. In one aspect, the method includes lubricating a driveline component with any embodiment of the lubricating composition described herein. In another embodiment, the method includes a lubricating composition comprising one or more base oils having lubricating viscosity; an oil-soluble hydrocarbyl-substituted melamine derivative having the structure of Formula I

[0022]

[0023] wherein each of R1, R2, and R3 is independently -NH2, a hydrocarbyl-substituted succinimide group, or a hydrocarbyl-substituted dicarboxylic acid-amide group, and wherein one or both of R1, R2, and R3 are independently a hydrocarbyl-substituted succinimide group or a hydrocarbyl-substituted dicarboxylic acid-amide group, and the remaining of R1, R2, and R3 are independently -NH2 or a hydrocarbyl-substituted dicarboxylic acid-amide; and / or wherein the lubricating composition has less than about 215 ppm of copper after being tested at 150 °C for 168 hours according to ASTM D130; and / or wherein the hydrocarbyl substituent of the succinimide group or the dicarboxylic acid-amide group is a C12 to C30 hydrocarbyl group; and / or wherein the oil-soluble hydrocarbyl-substituted melamine derivative is a reaction product of a hydrocarbyl-substituted succinic acid or anhydride and melamine, wherein the hydrocarbyl-substituted succinic acid or anhydride is in molar excess relative to melamine; and / or wherein the molar ratio of the hydrocarbyl-substituted succinic anhydride to melamine is from about 1.1:1 to about 4:1; and / or wherein one of R1, R2, and R3 is independently a hydrocarbyl-substituted succinimide group or a hydrocarbyl-substituted dicarboxylic acid-amine group, and the remaining two of R1, R2, and R3 are -NH2 groups; and / or wherein two of R1, R2, and R3 are independently a hydrocarbyl-substituted succinimide group or a hydrocarbyl-substituted dicarboxylic acid-amine group, and the remaining one of R1, R2, and R3 is an -NH2 group; and / or wherein the lubricating composition has a kV100 viscosity of from about 3 cSt to about 10 cSt; and / or wherein the oil-soluble hydrocarbyl-substituted melamine derivative provides from about 5 ppm to about 1100 ppm of nitrogen to the lubricating composition; and / or wherein the lubricating composition comprises from about 0.01 wt% to about 0.5 wt% of the oil-soluble hydrocarbyl-substituted melamine derivative; and / or wherein the lubricating composition further comprises less than about 1 wt% of an alkylated diphenylamine; and / or wherein the driveline is an automatic transmission.

[0024] In yet another method or embodiment, the use of any embodiment of a corrosion inhibitor in the form of an oil-soluble hydrocarbyl-substituted melamine derivative is described herein for lubricating a driveline and, in some embodiments, for lubricating a driveline in which the driveline lubricating composition is substantially free of tolyltriazole additives or derivatives thereof, and in further embodiments, the use has less than about 215 ppm of copper after being tested at 150 °C for 168 hours in accordance with ASTM D130.

[0025] Other embodiments of the disclosure will be apparent to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. The following term definitions are provided to clarify the meaning of certain terms as used herein. Detailed Description

[0026] In one method, a melamine-based compound is disclosed herein that, in one embodiment, is suitable as a corrosion inhibitor for lubricating compositions, particularly for transmission fluids (e.g., manual, automatic, dual clutch, or electric), axle fluids, differential fluids, tractor fluids, industrial gear fluids, and / or lubricating fluids for other gear-type applications. In other methods or embodiments, the melamine-based compound of the disclosure is in the form of an oil-soluble hydrocarbyl-substituted melamine derivative that, in one method, is the reaction product of a hydrocarbyl-substituted succinic acid or anhydride (e.g., alkenyl succinic acid or anhydride) and melamine under conditions effective to form a hydrocarbyl-substituted melamine-based succinimide or acid / amide compound.

[0027] In an exemplary method or embodiment, suitable reaction conditions for forming the melamine compounds herein may include a reaction temperature of from about 50 °C to about 200 °C (in other methods, from about 50 °C to about 150 °C or from about 100 °C to about 200 °C) and a reaction time of from about 1 hour to about 20 hours (in other methods, from about 4 hours to about 16 hours, and in other methods, from about 6 hours to about 12 hours). The reaction conditions may also include a molar excess of the hydrocarbyl-substituted succinic acid or anhydride reactant (e.g., alkenyl succinic acid or anhydride) relative to the melamine reactant. Suitable hydrocarbyl-substituted succinic acid or anhydride reactants may include, for example, C12 to C30 alkenyl succinic acids or anhydrides (preferably C12 to C24 alkenyl succinic acids or anhydrides, or most preferably C12 to C16 alkenyl succinic acids or anhydrides), and more specifically, suitable reactants include, but are not limited to, C20-C24 α-olefins reacted with maleic acid or anhydride, hexadecenyl succinic acid or anhydride, dodecenyl succinic acid or anhydride, combinations thereof, and similar hydrocarbyl succinic acids or anhydrides. In other methods, the hydrocarbyl-substituted succinic acid or anhydride reactant may also be tetrapropenyl alkenyl succinic acid or anhydride, n-dodecyl alkenyl succinic acid or anhydride. In an alternative method, polyisobutylene-substituted acids or anhydrides (e.g., PIBSA) may also be suitable as starting reactants, preferably having a number average molecular weight of up to about 450 for the polyisobutylene, up to about 1000, or up to about 1500, or up to about 2500 (or any range therebetween) in other methods.

[0028] In one method or embodiment, the oil-soluble hydrocarbyl-substituted melamine derivatives of the present disclosure suitable for corrosion inhibitors have the structure of Formula I

[0029]

[0030] wherein each of R1, R2, and R3 is independently -NH2, a hydrocarbyl-substituted succinimide group (i.e., Formula II below) or a hydrocarbyl-substituted dicarboxylic acid-amide group (i.e., Formula III below). In one method, one or two of R1, R2, and R3 are independently a hydrocarbyl-substituted succinimide group or a hydrocarbyl-substituted dicarboxylic acid-amide group, and the remaining R1, R2, and / or R3 is an -NH2 group or a hydrocarbyl-substituted dicarboxylic acid-amide group. In another method, one or two of R1, R2, and R3 are independently a hydrocarbyl-substituted succinimide group, and the remaining R1, R2, and / or R3 is a hydrocarbyl-substituted dicarboxylic acid-amide group. The hydrocarbyl-substituted succinimide group may have the structure of Formula II and the hydrocarbyl-substituted dicarboxylic acid-amide group may have the structure of Formula III (where ~ represents a bond to the central melamine moiety):

[0031]

[0032]

[0033] In other methods, one of R1, R2, and R3 is independently a hydrocarbyl-substituted succinimide group or a hydrocarbyl-substituted dicarboxylic acid-amide group, and in another method, two of R1, R2, and R3 are independently a hydrocarbyl-substituted succinimide group or a hydrocarbyl-substituted dicarboxylic acid-amide group. In either case, the remaining R1, R2, and R3 groups are hydrocarbyl-substituted dicarboxylic acid-amide groups or -NH2 groups, preferably -NH2 groups. In another method or embodiment, the hydrocarbyl substituent (e.g., the hydrocarbyl group of the R1, R2, and / or R3 moieties (i.e., the R group of Formula II or III above)) is a C12 to C30 hydrocarbyl group, preferably the hydrocarbyl substituent is a C12 to C24 hydrocarbyl group, and most preferably is a C12 hydrocarbyl group, a C16 hydrocarbyl group, a C20 hydrocarbyl group, a C24 hydrocarbyl group, or any mixture thereof.

[0034] As described above, the oil-soluble hydrocarbyl-substituted melamine derivatives herein can be prepared in a reaction having a molar excess of a hydrocarbyl-substituted succinimide acid or anhydride reactant relative to the melamine reactant. In one embodiment, this molar excess is reflected in a molar ratio of the hydrocarbyl-substituted succinic acid or anhydride reactant to the melamine reactant of from about 1.1:1 to about 4:1, and in another embodiment, the molar ratio of the hydrocarbyl-substituted succinic acid or anhydride reactant to the melamine reactant is from about 1.1:1 to about 3:1, and in another embodiment, the molar ratio is from about 2.0:1 to about 3.0:1.

[0035] When the melamine derivatives herein are formed in a reaction under the above conditions and using a molar excess of a hydrocarbyl-substituted succinic anhydride, the resulting melamine derivatives have from about 5 wt% to about 25 wt% nitrogen and are capable of providing from about 5 ppm to about 1100 ppm nitrogen, from about 10 ppm to about 800 ppm nitrogen, from about 10 ppm to about 200 ppm nitrogen, from about 25 ppm to about 100 ppm nitrogen, preferably from about 25 ppm to about 80 ppm nitrogen, and more preferably from about 30 ppm to about 75 ppm nitrogen to a lubricant at a treatment rate of from about 0.01 wt% to about 0.5 wt%. In other embodiments, the oil-soluble hydrocarbyl-substituted melamine derivatives formed in a reaction under the above conditions and using a molar excess of a hydrocarbyl-substituted succinic anhydride have one or more of the following structures:

[0036]

[0037] Each of their R groups is a hydrocarbyl substituent as discussed above and is independently a C12 to C30 hydrocarbyl group, preferably a C12 to C24 hydrocarbyl group, most preferably a C12 hydrocarbyl group, a C16 hydrocarbyl group, a C20 hydrocarbyl group, a C24 hydrocarbyl group, or any mixture thereof.

[0038] As described above, the melamine derivatives herein are particularly suitable as corrosion inhibitors in lubricants, especially for lubricating compositions of transmission fluids (manual, automatic, dual clutch or electric), axle fluids, differential fluids, tractor fluids, industrial gear fluids and / or lubricating fluids for other gear-type applications, and such lubricating compositions containing a melamine-based corrosion inhibitor. In one method or embodiment, such lubricating compositions may contain from about 0.01 wt% to about 0.5 wt% of the melamine derivatives herein (preferably from about 0.02 wt% to about 0.1 wt%, more preferably from about 0.03 wt% to about 0.08 wt%). Using this melamine derivative, the lubricating compositions herein may exhibit less than about 215 ppm of copper leaching (preferably less than 100 ppm of copper, more preferably less than about 80 ppm of copper) after being tested at 150 °C for 168 hours according to a modified version of ASTM D130. Compositions herein having such amounts of melamine derivatives may also exhibit a copper tarnish rating of 4a to 4b. Most surprisingly, the lubricating compositions herein can achieve such low levels of copper leaching and tarnish ratings in compositions substantially free of the existing methylbenzotriazole additive, meaning that the compositions herein have less than 0.1 wt% of methylbenzotriazole additive, less than about 0.05 wt% of methylbenzotriazole additive, less than about 0.01 wt% of methylbenzotriazole additive, or preferably no functional amount and / or no detectable amount of methylbenzotriazole additive.

[0039] The lubricating compositions herein may contain the above melamine-based corrosion inhibitor in combination with other additives suitable for the above lubricant applications. In some embodiments, such additional additives may include one or more of the following: phosphorus antiwear additives, sulfur antiwear additives, antioxidants (including amine antioxidants), viscosity modifiers, and synthetic or mineral base oils to provide a kinematic viscosity (ASTM D445) of from about 3 cSt to about 10 cSt at 100 °C. Preferably, the lubricant has a trace level of water (e.g., about 0.5 wt% or less, about 0.1 wt% or less, or 0.05 wt% or less), and preferably is water-free or has no detectable level of water.

[0040] Base oil

[0041] Suitable base oils for the lubricating compositions according to the present disclosure can be mineral oils, animal oils, vegetable oils, synthetic oils, or mixtures thereof.

[0042] Natural oils can include animal and vegetable oils (such as castor oil, lard), and mineral oils, such as liquid petroleum and solvent-treated or acid-treated paraffinic, naphthenic, or mixed paraffinic-naphthenic type mineral lubricating oils. Mineral oils can include oils obtained by drilling or oils from plants and animals or any mixture thereof. For example, such oils can include, but are not limited to: castor oil, lard, olive oil, peanut oil, corn oil, soybean oil, and linseed oil, as well as mineral lubricating oils, such as liquid petroleum and solvent-treated or acid-treated mineral lubricating oils of paraffinic, naphthenic, or mixed paraffinic-naphthenic types. If desired, such oils can be partially or fully hydrogenated. Oils derived from coal or shale can also be suitable. Additionally, oils derived from the gas-to-liquid process are also suitable. As measured by ASTM D2270-10, the base oil can have a kinematic viscosity of about 2 cSt to about 15 cSt at 100 °C.

[0043] Useful synthetic lubricating oils can include hydrocarbon oils, such as polymerized, oligomerized, or copolymerized olefins (e.g., polybutene, polypropylene, propylene-isobutylene copolymer); poly(1-hexene), poly(1-octene), trimers or oligomers of 1-decene, such as poly(1-decene), such materials are commonly 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 and their derivatives, analogs, and homologs or mixtures thereof. Poly-α-olefins are typically hydrogenated materials.

[0044] Other synthetic lubricating oils include polyol esters containing phosphoric acid, diesters, liquid esters (e.g., tolyl phosphate, trioctyl phosphate, and diethyl decylphosphonate), or polytetrahydrofuran. Synthetic oils can be produced by the Fischer-Tropsch reaction and are typically hydroisomerized Fischer-Tropsch hydrocarbons or waxes. In one embodiment, the oil can be prepared by the Fischer-Tropsch gas-liquid synthesis process and other gas-liquid oils.

[0045] The base oil or base oils having lubricating viscosity used in the compositions herein can be a single base oil, or can be a mixture of two or more base oils. The one or more base oils can be selected from any of Groups I to V specified in the American Petroleum Institute (API) Base Oil Interchangeability Guidelines. These base oil groups are as follows:

[0046] Table 1: Base oil types

[0047]

[0048] Groups I, II, and III are mineral oil treatment feedstocks. Group IV base oils contain synthetic molecular species that are prepared by the polymerization of olefinically unsaturated hydrocarbons. API Group IV base oils, polyalphaolefins (PAOs), are typically derived from monomers having 4 to 30 or 4 to 20 or 6 to 16 carbon atoms. Examples of PAOs that can be used in the present invention include those derived from octene, decene, mixtures thereof, and the like. As measured by ASTM D2270-10, PAOs can have a kinematic viscosity at 100 °C of 2 to 15, or 3 to 12, or 4 to 8 cSt. Suitable PAO viscosities include 4 cSt at 100 °C and 6 cSt at 100 °C, and mixtures thereof. Many Group V base oils are also true synthetic products and can include diesters, polyol esters, polyalkylene glycols, alkylated aromatics, polyphosphates, polyethylene ethers, and / or polyphenylene ethers, etc., but can also be naturally occurring oils such as vegetable oils. It should be noted that although Group III base oils are derived from mineral oils, the rigorous processing these fluids undergo results in their physical properties being very similar to some true synthetic oils. Thus, oils derived from Group III base oils can be referred to as synthetic fluids in the industry. Suitable oils can be derived from hydrocracked, hydrogenated, hydrorefined, unrefined, refined, and re-refined oils, and mixtures thereof.

[0049] Unrefined oils are those oils derived from natural, mineral, or synthetic sources that have not had, or have had very little, further purification treatment. Refined oils are similar to unrefined oils, except that they have been subjected to one or more purification steps, which may result in an improvement in one or more properties. Examples of suitable purification techniques are solvent extraction, secondary distillation, acid or base extraction, filtration, percolation, and the like. Oils refined to edible quality may or may not be useful. Edible oils can also be referred to as white oils. In some embodiments, the lubricating oil composition does not contain edible oils or white oils.

[0050] Re-refined oils are also referred to as reclaimed oils or reprocessed oils. Similar to refined oils, these oils are obtained using the same or similar processes. Typically these oils are further processed by techniques directed at removing spent additives and oil decomposition products.

[0051] The base oil is combined with the additive compositions disclosed in the embodiments herein to provide a lubricating fluid for transmissions, axles, traction machines, or industrial gears. Thus, the base oil can be present in the lubricating fluid in an amount greater than about 80 wt% based on the total weight of the lubricating fluid. In some embodiments, the base oil can be present in the lubricating fluid in an amount greater than about 85 wt% based on the total weight of the lubricating fluid and can be selected from any suitable synthetic or natural oil or mixtures thereof having a suitable lubricating viscosity.

[0052] Suitable transmission, axle, differential, traction machine, or industrial gear lubricant compositions herein can include additive components within the ranges listed in Table 2.

[0053] Table 2: Suitable transmission system or gear fluid compositions

[0054]

[0055] Based on the weight of the total lubricating oil composition, the percentage of each component above represents the weight % of each component. The balance of the lubricating oil composition consists of one or more base oils. The additives used to formulate the compositions herein can be blended into the base oil individually or in various sub-combinations. However, it may be suitable to use an additive concentrate (i.e., additives plus a diluent such as a hydrocarbon solvent) to blend all components simultaneously.

[0056] The lubricating compositions described herein can be formulated to provide lubrication, sufficient load-carrying capacity, and improved copper corrosion for various applications. The lubricating fluid according to the present disclosure can be used for transmission fluids, axle fluids, differential fluids, traction machine fluids, industrial gear fluids, and stationary gearboxes. Gear types can include, but are not limited to, spur gears, helical gears, worm gears, rack gears, involute gears, bevel gears, helical gears, planetary gears, and hypoid gears, as well as limited-slip applications and differentials. The driveline lubricating compositions disclosed herein are also suitable for automatic or manual transmissions, including stepped automatic transmissions, continuously variable transmissions, semi-automatic transmissions, automated manual transmissions, toroidal transmissions, and dual-clutch transmissions. The driveline lubricating compositions herein are particularly suitable for axles, transfer cases, differentials, such as straight differentials, steering differentials, limited-slip differentials, clutch-type differentials, and locking differentials, etc.

[0057] Optional additives

[0058] In other methods, lubricants containing such additives as described above can also contain one or more optional components, provided that such components and their amounts do not affect the performance characteristics as described in the above paragraphs. These optional components are described in the following paragraphs.

[0059] Phosphorus-containing compounds

[0060] The lubricant compositions of the present invention may comprise one or more phosphorus-containing compounds that confer antiwear benefits to the fluid. The one or more phosphorus-containing compounds are present in the lubricating oil composition in an amount in the range of from about 0 wt% to about 5 wt% or from about 0.01 wt% to about 4 wt% or from about 0.05 wt% to about 3 wt% or from about 0.1 wt% to about 3 wt% of the lubricating oil composition. The phosphorus-containing compound may provide up to 500 ppm of phosphorus or from about 3 ppm to about 100 ppm of phosphorus or from about 4 ppm to about 20 ppm of phosphorus or up to 50 ppm of phosphorus or up to 20 ppm of phosphorus to the lubricant composition.

[0061] One or more phosphorus-containing compounds may include ashless phosphorus-containing compounds. Examples of suitable phosphorus-containing compounds include, but are not limited to, thiophosphates, dithiophosphates, phosphates, phosphoric esters, phosphate esters, phosphites, phosphonates, phosphorus-containing carboxylic esters, ethers, or their amide salts, and mixtures thereof. Phosphorus-containing antiwear agents are more fully described in European Patent 0612839.

[0062] It should be noted that the terms phosphonate and phosphite are often used interchangeably in the lubricant industry. For example, dibutyl hydrogen phosphonate is commonly referred to as dibutyl hydrogen phosphite. The lubricant compositions of the present invention include phosphorus-containing compounds that can be referred to as phosphites or phosphonates within the scope of the present invention.

[0063] In any of the above phosphorus-containing compounds, the compound may have from about 4 wt% to about 8 wt% of phosphorus or from about 5 wt% to about 6 wt% of phosphorus.

[0064] In some embodiments, the ashless phosphorus-containing compound can be dialkyl dithiophosphates, pentyl phosphates, dipentyl phosphates, dibutyl hydrogen phosphonate, dimethyl octadecyl phosphonate, their salts, and mixtures thereof.

[0065] The ashless phosphorus-containing compound may have the following formula:

[0066]

[0067] wherein R1 is S or O; R2 is -OR, -OH, or -R''; R3 is -OR'', -OH, or SR'''C(O)OH; R4 is -OR''; R''' is a C1 to C3 branched or straight-chain alkyl chain; and R'' is a C1 to C 18 hydrocarbon chain. When the phosphorus-containing compound has the structure shown in Formula XIV, the compound may have from about 8 to about 16 wt% of phosphorus.

[0068] In some embodiments, the lubricating composition comprises a phosphorus-containing compound of Formula XIV, wherein R1 is O; R2 is H; R3 and R4 are each OR", where R" is C 18; wherein the phosphorus-containing compound is present in an amount to deliver from 3 ppm to 50 ppm of phosphorus or from 3 ppm to 20 ppm of phosphorus to the lubricating composition. In other embodiments, the lubricating composition comprises a phosphorus-containing compound of Formula XIV, wherein R1 is O; R2 is H; R3 and R4 are each OR”, wherein R” is an oil-based group; and wherein the phosphorus-containing compound is present in an amount to deliver from 3 ppm to 50 ppm of phosphorus or from 3 ppm to 20 ppm of phosphorus to the lubricating composition.

[0069] In some embodiments, the lubricant composition comprises a phosphorus-containing compound of Formula XIV, wherein R1 is S; R2 is -OR”; R3 is SR”'COOH; R4 is -OR”; R”' is a C3 branched alkyl chain; R” is C4; and wherein the phosphorus-containing compound is present in an amount to deliver from 3 ppm to 50 ppm of phosphorus to the lubricant composition.

[0070] In another embodiment, the lubricant composition comprises a phosphorus-containing compound of Formula XIV, wherein R1 is O; R2 is -OH; R3 is -OR” or -OH; R4 is -OR”; R” is C5; and wherein the phosphorus-containing compound is present in an amount to deliver from 3 ppm to 50 ppm of phosphorus to the lubricant composition.

[0071] In additional embodiments, the lubricant composition comprises a phosphorus-containing compound of Formula XIV, wherein R1 is O; R2 is OR”; R3 is H; R4 is -OR”; R” is C4; and wherein the one or more phosphorus-containing compounds are present in an amount to deliver from 3 ppm to 50 ppm of phosphorus to the lubricant composition.

[0072] In other embodiments, the lubricant composition comprises a phosphorus-containing compound of Formula XIV, wherein R1 is O; R2 is -R”; R3 is -OCH3 or -OH; R4 is -OCH3; R” is C 18 ; and wherein the one or more phosphorus-containing compounds are present in an amount to deliver from 3 ppm to 50 ppm of phosphorus to the lubricant composition.

[0073] Anti-wear agents

[0074] The lubricant composition may also comprise an antiwear agent that is a phosphorus-free compound. Examples of such antiwear agents include borate esters, borate ester epoxides, thiocarbamate compounds (including thiocarbamates, alkylene-coupled thiocarbamates, and bis(S-alkyl dithiocarbamoyl) disulfides, thiocarbamate amides, thiocarbamate ethers, alkylene-coupled thiocarbamates, and bis(S-alkyl dithiocarbamoyl) disulfides and mixtures thereof), sulfurized olefins, tridecyl adipate, titanium compounds, and long-chain derivatives of hydroxycarboxylic acids such as tartrate derivatives, tartramides, tartrimides, citrates, and mixtures thereof. A suitable thiocarbamate compound is molybdenum dithiocarbamate. Suitable tartrate derivatives or tartrimides may contain alkyl ester groups, where the total number of carbon atoms on the alkyl group can be at least 8. The tartrate derivative or tartrimide may contain alkyl ester groups, where the total number of carbon atoms on the alkyl group can be at least 8. In one embodiment, the antiwear agent may include citrate esters. The additional antiwear agent may be present in the range of about 0 wt% to about 5 wt%, or about 0.01 wt% to about 4 wt%, or about 0.05 wt% to about 3 wt%, or about 0.1 wt% to about 3 wt% of the lubricating oil composition.

[0075] Sulfur-containing compounds

[0076] The lubricant composition of the present disclosure may also comprise a sulfur-containing compound that provides extreme pressure performance, provided that the lubricating composition herein includes the noted amounts and distributions described herein.

[0077] A variety of sulfur-containing extreme pressure agents are suitable and include sulfurized animal or vegetable fats or oils, sulfurized animal or vegetable fatty acid esters, fully or partially esterified esters of trivalent or pentavalent acids of phosphorus, sulfurized olefins (see, for example, U.S. Patent 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, for example, U.S. Patent 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 1,162,334), functionally substituted dihydrocarbyl polysulfides (see, for example, U.S. Patent No. 4,218,332), and polysulfide olefin products (see, for example, U.S. Patent No. 4,795,576).

[0078] A suitable class of extreme pressure agents is a polysulfide composed of one or more compounds represented by the formula: Ra-S x -Rb, where Ra and Rb are hydrocarbon groups, each hydrocarbon group may contain from 1 to 18 and in other methods from 3 to 18 carbon atoms, x can be from 2 to 8, and typically is from 2 to 5, especially 3. In certain methods, x is an integer from 3 to 5, where about 30% to about 60% of x is an integer of 3 or 4. The hydrocarbon groups can have a wide variety of types, such as alkyl, cycloalkyl, alkenyl, aryl or aralkyl. Tertiary alkyl polysulfides can be used, such as di-tert-butyl trisulfide, and mixtures containing di-tert-butyl trisulfide (e.g., mixtures consisting mainly or entirely of trisulfide, tetrasulfide and pentasulfide). Examples of other useful dihydrocarbyl polysulfides include dipentyl polysulfide, dinonyl polysulfide, dodecyl polysulfide and dibenzyl polysulfide.

[0079] Another suitable class of extreme pressure agents is sulfurized isobutene prepared by reacting an olefin such as isobutene with sulfur. Sulfurized isobutene (SIB), especially sulfurized polyisobutene, typically has a sulfur content of about 10% to about 55% by weight, desirably about 30% to about 50% by weight. A variety of other olefins or unsaturated hydrocarbons, such as isobutene dimers or trimers, 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. Patent No. 3,471,404 to Myers; U.S. Patent No. 4,204,969 to Papay et al.; U.S. Patent No. 4,954,274 to Zaweski et al.; U.S. Patent No. 4,966,720 to DeGonia et al.; and U.S. Patent No. 3,703,504 to Horodysky et al., each of which is incorporated herein by reference.

[0080] Methods for preparing sulfurized olefins, including those disclosed in the above patents, generally involve forming a material commonly referred to as an "adduct", where the olefin reacts 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 typically measured by various physical properties, including, for example, viscosity, sulfur content, halogen content and weight loss in a copper corrosion test. U.S. Patent No. 4,966,720 relates to sulfurized olefins used as extreme pressure additives in lubricating oils and to a two-step reaction for their preparation.

[0081] In some embodiments, the extreme pressure agent is present in the lubricating composition in an amount of up to about 3.0 wt% or up to about 5.0 wt%. In other embodiments, based on the total lubricant composition, the extreme pressure agent is present in an amount of about 0.05 wt% to about 0.5 wt%. In other embodiments, based on the total lubricant composition, the extreme pressure agent is present in an amount of about 0.1 wt% to about 3.0 wt%. In other embodiments, based on the total lubricant composition, the extreme pressure agent is present in an amount between about 0.6 wt% and about 1 wt%.

[0082] Antioxidants

[0083] 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, sulfurized terpenes, sulfurized esters, aromatic amines, alkylated diphenylamines (e.g., nonyl diphenylamine, dinonyl diphenylamine, octyl diphenylamine, dioctyl diphenylamine), phenyl-α-naphthylamine, alkylated phenyl-α-naphthylamine, hindered non-aromatic amines, phenols, hindered phenols, oil-soluble molybdenum compounds, macromolecular antioxidants, or mixtures thereof. The antioxidant compounds can be used alone or in combination.

[0084] The hindered phenol antioxidant may contain secondary butyl and / or tertiary butyl as the sterically hindered group. The phenolic group may also be substituted by a hydrocarbon 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, or 4-butyl-2,6-di-tert-butylphenol, or 4-dodecyl-2,6-di-tert-butylphenol. In one embodiment, the hindered phenol antioxidant may be an ester and may include, for example, L-135 available from BASF or an addition product derived from 2,6-di-tert-butylphenol and an alkyl acrylate, wherein the alkyl group may 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 may be an ester and may include 4716 available from Albemarle Corporation. L-135 or an addition product derived from 2,6-di-tert-butylphenol and an alkyl acrylate, wherein the alkyl group may 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 may be an ester and may include 4716 available from Albemarle Corporation. 4716.

[0085] A particularly useful antioxidant comprises nonyl diphenylamine and dinonyl diphenylamine. In an embodiment, the lubricating oil composition may contain one or more of these diphenylamines in an amount of up to about 1 wt%.

[0086] The one or more antioxidants may be present in the lubricating oil composition in an amount ranging from about 0 wt% to about 3 wt%, or from about 0.1 wt% to about 1 wt%, or from about 0.1 wt% to about 0.5 wt%.

[0087] Dispersants

[0088] The lubricant composition may include one or more selected dispersants or mixtures thereof. Dispersants are commonly referred to as ashless dispersants because they do not contain ash-forming metals prior to incorporation into the lubricating oil composition and generally do not contribute any ash when added to the lubricant. Ashless dispersants are characterized by polar groups attached to a molecule or relatively high molecular weight hydrocarbon chain. Typical ashless dispersants include N-substituted long-chain alkenyl succinimides. N-substituted long-chain alkenyl succinimides include polyisobutylene (PIB) substituents, where the number average molecular weight of the polyisobutylene substituent ranges from about 800 to about 2500 as determined by gel permeation chromatography (GPC) using polystyrene (number average molecular weight of 180 to about 18,000) as a calibration standard. The PIB substituent for the dispersant has a viscosity at 100 °C of from about 2100 cSt to about 2700 cSt as determined using ASTM D445-18. The succinimide dispersants and their preparation are disclosed, for example, in U.S. Patent Nos. 7,897,696 and 4,234,435, which are incorporated herein by reference. Succinimide dispersants are generally imides formed from polyamines, typically poly(ethyleneamine). The dispersant may include two succinimide moieties linked by a polyamine. The polyamine may be tetraethylenepentamine (TEPA), triethylenetetramine (TETA), pentaethylenehexamine (PEHA), other higher homologues of diethylenetriamine, and / or mixtures thereof. The polyamine may be a mixture of straight-chain, branched-chain, and cyclic amines. The PIB substituent may be attached to each succinimide moiety.

[0089] In some embodiments, the lubricant composition comprises at least one polyisobutylene succinimide dispersant derived from polyisobutylene having a number average molecular weight in the range of about 350 to about 5000, or about 500 to about 3000, as measured by the GPC method described herein. The polyisobutylene succinimide may be used alone or in combination with other dispersants.

[0090] In some embodiments, when PIB is included, it may have a terminal double bond content of greater than 50 mol%, greater than 60 mol%, greater than 70 mol%, greater than 80 mol% or greater than 90 mol%. Such PIB is also referred to as highly reactive PIB ("HR-PIB"). HR-PIB with a number average molecular weight in the range of about 800 to about 5000 is suitable for the embodiments of the present disclosure. Conventional non-highly reactive PIB typically has a terminal double bond content of less than 50 mol%, less than 40 mol%, less than 30 mol%, less than 20 mol% or less than 10 mol%.

[0091] HR-PIB with a number average molecular weight in the range of about 900 to about 3000 may be suitable, as measured by the GPC method described herein. Such HR-PIB is commercially available or can be synthesized by polymerizing isobutene in the presence of a non-chlorinated catalyst such as boron trifluoride, as described in U.S. Patent Nos. 4,152,499 and 5,739,355. When used in the aforementioned thermal ene reaction, due to enhanced reactivity, HR-PIB can increase the conversion rate in the reaction and reduce the amount of sediment formation.

[0092] In some embodiments, the lubricant composition comprises at least one dispersant derived from polyisobutene succinic anhydride. In some embodiments, the dispersant may be derived from polyalphaolefin (PAO) succinic anhydride.

[0093] A suitable class of dispersants can be Mannich bases. Mannich bases are substances formed by the condensation of higher molecular weight alkyl-substituted phenols, polyalkylene polyamines and aldehydes such as formaldehyde. Mannich bases are described in more detail in U.S. Patent No. 3,634,515.

[0094] A suitable class of dispersants can be high molecular weight esters or semi-ester amides.

[0095] The dispersant can also be post-treated by conventional methods by reacting with any of a variety of reagents. These reagents include boron, urea, thiourea, dimercaptothiadiazole, carbon disulfide, aldehydes, ketones, carboxylic acids, hydrocarbon-substituted succinic anhydrides, maleic anhydride, nitriles, epoxides, carbonates, cyclic carbonates, hindered phenol esters and phosphorus compounds. U.S. Patent Nos. 7,645,726; 7,214,649; and 8,048,831 describe some suitable post-treatment methods and post-treatment products.

[0096] Suitable boron compounds useful for forming the dispersants herein include any boron compound or mixture of boron compounds capable of introducing a boron-containing material into an ashless dispersant. Any organic or inorganic boron compound capable of undergoing such a reaction can be used. Thus, boron oxide, boron oxide hydrates, boron trifluoride, boron tribromide, boron trichloride, HBF4, boric acids such as metaboric acid (e.g., alkyl-B(OH)2 or aryl-B(OH)2), boric acid (i.e., H3BO3), tetraboric acid (i.e., H2B5O7), metaboric acid (i.e., HBO2), ammonium salts of such boric acids, and esters of such boric acids can be used. The use of complexes of boron trihalides with ethers, organic acids, inorganic acids, or hydrocarbons is a convenient method of introducing boron reactants into the reaction mixture. Such complexes are known, e.g., boron trifluoride-diethyl ether, boron trifluoride-phenol, boron trifluoride-phosphoric acid, boron trichloride-chloroacetic acid, boron tribromide-dioxane, and boron trifluoride-methyl ethyl ether.

[0097] Suitable phosphorus compounds useful for forming the dispersants herein include phosphorus compounds or mixtures of phosphorus compounds capable of introducing a phosphorus-containing material into an ashless dispersant. Thus, any organic or inorganic phosphorus compound capable of undergoing such a reaction can be used. Thus, these inorganic phosphorus compounds such as inorganic phosphoric acids and inorganic phosphorus oxides, including their hydrates, can be used. Typical organic phosphorus compounds include the full esters and partial esters of phosphoric acid, such as phosphoric acid monoesters, phosphoric acid diesters, phosphoric acid triesters, thiophosphoric acid, dithiophosphoric acid, trithiophosphoric acid, and tetrathiophosphoric acid; phosphorous acid monoesters, phosphorous acid diesters, phosphorous acid triesters, thiophosphorous acid, dithiophosphorous acid; trithiophosphorous acid and dithiophosphorous acid; trialkylphosphine oxides: trialkylphosphine sulfides; monoalkylphosphonate and dialkylphosphonate (RPO(OR')(OR”), where R and R' are hydrocarbon groups and R” is a hydrogen atom or a hydrocarbon group), and their mono-, di-, tri-thio analogs; monoalkylphosphonite and dialkylphosphonite (RP(OR')(OR”), where R and R' are hydrocarbon groups and R” is a hydrogen atom or a hydrocarbon group) and their mono-thio and di-thio analogs; and so on. Thus, such compounds can be used, e.g., phosphorous acid (H3PO3, sometimes described as H2(HPO3), sometimes called orthophosphorous acid or phosphonic acid), phosphoric acid (H3PO4, sometimes called orthophosphoric acid), hypophosphoric acid (H4P2O6), metaphosphoric acid (HPO3), pyrophosphoric acid (H4P2O7), hypophosphorous acid (H3PO2, sometimes called phosphinic acid), pyrophosphorous acid (H4P2O5, sometimes called pyrophosphinic acid), phosphinous acid (H3PO), tripolyphosphoric acid (H5P3O 10 )、tetrapolyphosphoric acid (H5P4O 13) Phosphoric acid (H3P3O9), phosphorus trioxide, phosphorus tetraoxide, phosphorus pentoxide, etc. Some sulfur or all-sulfur analogues, such as thioacetic acid (H3PS4), thiophosphoric acid (H3PO3S), dithiophosphoric acid (H3P2S2), trithiophosphoric acid (H3POS3), sesquisulfide of phosphorus, diphosphorus heptasulfide and diphosphorus pentasulfide (P2S5, sometimes called P4S 10 ), can also be used to form the dispersants of the present disclosure. Inorganic phosphorus halide compounds such as PCl3, PBr3, POCl3, PSCl3, etc. can also be used.

[0098] Organic phosphorus compounds such as mono-, di- and triesters of phosphoric acid (e.g., trialkyl phosphates, dialkyl monoacid phosphates, monoalkyl diacid phosphates and mixtures thereof), mono-, di- and triesters of phosphorous acid (e.g., trialkyl phosphites, dialkyl hydrogen phosphites, alkyl diacid phosphites and mixtures thereof), esters of phosphonic acid (“primary” RP(O)(OR)2 and “secondary” R2P(O)(OR)), esters of hypophosphorous acid, phosphoryl halides (e.g., RP(O)Cl2 and R2P(O)Cl), halogenated phosphites (e.g., (RO)PCl2 and (RO)2PCl), halogenated phosphates (e.g., ROP(O)Cl2 and (RO)2P(O)Cl), triester of pyrophosphoric acid (e.g., (RO)2P(O)-O-P(O)(OR)2), and partial sulfur analogues of any of the foregoing organic phosphorus compounds, etc., wherein each alkyl group contains at most about 100 carbon atoms or at most about 50 carbon atoms or at most about 24 carbon atoms or at most about 12 carbon atoms. Halogenated phosphine halides (e.g., alkyltetrachlorophosphorus, dialkyldichlorophosphorus and trialkylmonochlorophosphorus) and halogenated phosphines (monohalophosphines and dihalophosphines) can also be used.

[0099] The lubricants herein may include a mixture of one or more of the above-mentioned borated and phosphorylated dispersants and non-borated and non-phosphorylated dispersants.

[0100] In one embodiment, the lubricating oil composition may comprise at least one borated dispersant, wherein the dispersant is a reaction product of an olefin copolymer or an olefin copolymer with succinic anhydride, and at least one polyamine. The ratio of PIBSA: polyamine can be from 1:1 to 10:1, or from 1:1 to 5:1, or from 4:3 to 3:1, or from 4:3 to 2:1. Particularly suitable dispersants contain, as determined by the GPC method described herein, polyisobutylene groups of PIBSA with a number average molecular weight (Mn) in the range of about 500 to 5000, and (B) polyamine, which has the general formula H2N(CH2) m -[NH(CH2) m n -NH2, where m is in the range of 2 to 4 and n is in the range of 1 to 2. ​

[0101] In addition to the above, the dispersant can be post-treated with aromatic carboxylic acids, aromatic polycarboxylic acids or aromatic acid anhydrides, where all carboxylic acid or acid anhydride groups are directly attached to the aromatic ring. Such carboxyl-containing aromatic compounds can be selected from 1,8-naphthalenedicarboxylic acid or anhydride and 1,2-naphthalenedicarboxylic acid or anhydride, 2,3-naphthalenedicarboxylic acid or anhydride, naphthalene-1,4-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, phthalic anhydride, pyromellitic dianhydride, 1,2,4-benzenetricarboxylic anhydride, biphenyl dicarboxylic acid or anhydride, 2,3-pyridinedicarboxylic acid or anhydride, 3,4-pyridinedicarboxylic acid or anhydride, 1,4,5,8-naphthalenetetracarboxylic acid or anhydride, perylene-3,4,9,10-tetracarboxylic dianhydride, pyrene dicarboxylic acid or anhydride, etc. The molar ratio of such post-treatment components per mole of polyamine reaction can be in the range of about 0.1:1 to about 2:1. The typical molar ratio of such post-treatment components to polyamine in the reaction mixture can be in the range of about 0.2:1 to about 2:1. Another molar ratio of such post-treatment components to polyamine that can be used can be in the range of 0.25:1 to about 1.5:1. Such post-treatment components can react with other components at a temperature of about 140 °C to about 180 °C.

[0102] Alternatively, or in addition to the post-treatment described above, the dispersant can be post-treated with non-aromatic dicarboxylic acids or acid anhydrides. The number average molecular weight of the non-aromatic dicarboxylic acid or acid anhydride can be less than 500, as measured by the GPC method described herein. Suitable carboxylic acids or their acid anhydrides can include, but are not limited to, acetic acid or anhydride, oxalic acid and anhydride, malonic acid and anhydride, succinic acid and anhydride, alkenyl succinic acid and anhydride, glutaric acid and anhydride, adipic acid and anhydride, pimelic acid and anhydride, suberic acid and anhydride, azelaic acid and anhydride, sebacic acid and anhydride, maleic acid and anhydride, fumaric acid and anhydride, tartaric acid and anhydride, glycolic acid and anhydride, 1,2,3,6-tetrahydronaphthalenedicarboxylic acid and anhydride, etc.

[0103] The non-aromatic carboxylic acid or acid anhydride reacts with the polyamine in a molar ratio in the range of about 0.1 mole to about 2.5 moles per mole of polyamine. Typically, the amount of non-aromatic carboxylic acid or acid anhydride used will be relative to the number of secondary amino groups in the polyamine. Thus, about 0.2 moles to about 2.0 moles of non-aromatic carboxylic acid or acid anhydride per secondary amino group in component B can react with other components to provide a dispersant according to an embodiment of the present disclosure. Another molar ratio of non-aromatic carboxylic acid or acid anhydride to polyamine that can be used can be 0.25:1 to about 1.5:1 moles per mole of polyamine. The non-aromatic carboxylic acid or acid anhydride can react with other components at a temperature of about 140 °C to about 180 °C.

[0104] The active ingredient weight % of alkenyl or alkyl succinic anhydride can be determined using chromatographic techniques. Such a method is described in columns 5 and 6 of U.S. Patent No. 5,334,321. Using the equations in columns 5 and 6 of U.S. Patent No. 5,334,321, the conversion percentage of polyolefin is calculated from the active %.

[0105] The TBN of a suitable borated dispersant can be from about 10 mg to about 65 mg KOH per gram of composition on an oil-free basis, which corresponds to a TBN of from about 5 mg to about 30 mg KOH per gram of composition if measured on a dispersant sample containing about 50% diluent oil.

[0106] Typically, the above dispersant is provided in the lubricant at from about 4.5 wt% to about 10 wt%, and in other methods at from about 4.5 wt% to about 8 wt%, and in still other methods at from about 4.5 wt% to about 7.7 wt%.

[0107] Viscosity index improvers

[0108] The lubricant compositions herein may also optionally contain one or more viscosity index improvers. Suitable viscosity index improvers can include polyolefins, olefin copolymers, ethylene / propylene copolymers, polyisobutylene, hydrogenated styrene-isoprene polymers, styrene / maleate copolymers, hydrogenated styrene / butadiene copolymers, hydrogenated isoprene polymers, α-olefin maleic anhydride copolymers, polymethacrylates, polyacrylates, polyalkylstyrenes, hydrogenated vinyl aromatic conjugated diene copolymers, or mixtures thereof. Other viscosity index improvers can include star polymers, and suitable examples are described in U.S. Publication No. 20120101017A1, which is incorporated herein by reference.

[0109] The lubricating oil compositions herein may also optionally contain one or more dispersant viscosity index improvers in addition to or in place of the viscosity index improvers. Suitable viscosity index improvers can include functionalized polyolefins, such as ethylene-propylene copolymers that have been functionalized with the reaction product of an acylating agent (such as maleic anhydride) and an amine; polymethacrylates functionalized with an amine, or esterified maleic anhydride-styrene copolymers reacted with an amine.

[0110] The total amount of the viscosity index improver and / or the dispersant viscosity index improver can be from about 0 wt% to about 10 wt%, from about 0.1 wt% to about 8 wt%, from about 0.1 wt% to about 6 wt% of the lubricating oil composition.

[0111] In some embodiments, the viscosity index improver is a polyolefin or olefin copolymer having a number average molecular weight of from about 10,000 to about 500,000, from about 50,000 to about 200,000, or from 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 from about 40,000 to about 500,000, from about 50,000 to about 200,000, or from about 50,000 to about 150,000. In some embodiments, the viscosity index improver is a polymethacrylate having a number average molecular weight of from about 10,000 to about 500,000, from about 50,000 to about 200,000, or from about 50,000 to about 150,000.

[0112] Other optional additives

[0113] Other additives may be selected to perform one or more functions required of the lubricant composition. Additionally, one or more of the additives mentioned may be multifunctional and provide functionalities other than or different from those specified herein. The other additives may be additives other than the specified additives of the present disclosure and / or may include one or more of the following: metal deactivators, viscosity index improvers, ashless TBN boosters, antiwear agents, corrosion inhibitors, rust inhibitors, dispersants, dispersant viscosity index improvers, extreme pressure agents, antioxidants, foam inhibitors, demulsifiers, emulsifiers, pour point depressants, seal swell agents, and mixtures thereof. Generally, a fully formulated lubricating oil will contain one or more of these additives.

[0114] Suitable metal deactivators may include derivatives of benzotriazole (typically methylbenzotriazole), dimercaptothiadiazole derivatives, 1,2,4-triazoles, benzimidazoles, 2-alkyldithiobenzimidazoles, or 2-alkyldithiobenzothiazoles; foam inhibitors, including copolymers of ethyl acrylate and 2-ethylhexyl acrylate and optionally vinyl acetate; demulsifiers, including trialkyl phosphates, polyethylene glycols, polyethylene oxides, polypropylene oxides, and (ethylene oxide - propylene oxide) polymers; pour point depressants, including esters of maleic anhydride - styrene, polymethacrylates, polyacrylates, or polyacrylamides.

[0115] Suitable foam inhibitors include silicon-based compounds such as siloxanes.

[0116] 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.

[0117] An antifoaming agent / surfactant may also be included in the fluid according to the present invention. Various reagents are known for such use. A copolymer of ethyl acrylate and hexyl acrylate may be used, such as PC-1244 available from Solutia, Inc. In other embodiments, a silicone fluid such as 4% DCF may be included. A mixture of antifoaming agents may also be present in the lubricant composition.

[0118] The terms "gear oil", "gear fluid", "gear lubricant", "base gear lubricant", "lubricating oil", "lubricant composition", "lubricating composition", "lubricant" and "lubricating fluid" refer to finished lubricating products that contain a major amount of a base oil as discussed herein and a minor amount of an additive composition as discussed herein. Such gear fluids are used in extreme pressure situations, such as in transmissions and gear drive components having metal-to-metal contact situations, for example in transmissions (manual, automatic, dual clutch or electric) and / or gear differentials.

[0119] As used herein, the term "hydrocarbyl substituent" or "hydrocarbyl group" is used in its ordinary sense, which is well known to those skilled in the art. Specifically, it refers to a group having a carbon atom directly attached to the remainder of the molecule and predominantly having hydrocarbon character. Each hydrocarbyl group is independently selected from hydrocarbon substituents and substituted hydrocarbon substituents containing one or more of halogen groups, hydroxy groups, alkoxy groups, mercapto groups, nitro groups, nitroso groups, amino groups, pyridyl groups, furyl groups, imidazolyl groups, oxygen and nitrogen, and wherein there are no more than two non-hydrocarbon substituents per ten carbon atoms in the hydrocarbyl group.

[0120] As used herein, unless otherwise expressly stated, the term "percent by weight" or "wt% " or "weight percent" means the percentage of the component by weight of the entire composition. Unless otherwise indicated, all percentages herein are weight percentages. As used herein, "free of" means less than about 0.1 weight %, less than about 0.05 weight %, less than about 0.01 weight % or no official amount of such component.

[0121] The terms "soluble", "oil-soluble" or "dispersible" as 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 all proportions. However, the foregoing terms do mean that they are, for example, soluble, suspendable, dissolvable or stably dispersible in oil to an extent sufficient to perform their intended function in an environment in which oil is employed. Additionally, incorporation of other additives, if desired, may also permit incorporation of higher levels of a particular additive.

[0122] As used herein, the term "alkyl" refers to straight-chain, branched-chain, cyclic, and / or substituted saturated chain moieties of from about 1 to about 200 carbon atoms. As used herein, the term "alkenyl" refers to straight-chain, branched-chain, cyclic, and / or substituted unsaturated chain moieties of from about 3 to about 30 carbon atoms. As used herein, the term "aryl" refers to monocyclic and polycyclic aromatic compounds, which may include alkyl, alkenyl, alkylaryl, amino, hydroxy, alkoxy, halogen substituents, and / or heteroatoms including but not limited to nitrogen and oxygen.

[0123] As used herein, molecular weight is determined by gel permeation chromatography (GPC) using commercially available polystyrene standards (having an Mn of from about 180 to about 18,000 as the calibration reference). The molecular weight (Mn) of any embodiment herein can be measured using an instrument such as a gel permeation chromatography (GPC) instrument obtained from Waters, and the data can be processed using software such as Waters Empower software. The GPC instrument can be equipped with a Waters separation module and a Waters refractive index detector (or similar optional equipment). The GPC operating conditions can include a guard column, 4 Agilent PL gel columns (length 300×7.5 mm; particle size is 5 μm, and the pore size range is ), the column temperature is about 40 °C. Unstabilized HPLC grade tetrahydrofuran (THF) can be used as the solvent, and the flow rate is 1.0 mL / min. The GPC instrument can be calibrated with commercially available polystyrene (PS) standards having a narrow molecular weight distribution in the range of 500 g / mol to 380,000 g / mol. For samples with a mass less than 500 g / mol, the calibration curve can be extrapolated. The samples and PS standards can be dissolved in THF and prepared at a concentration of 0.1 wt% to 0.5 wt% and used without filtration. GPC measurements are also described in US 5,266,223, which is incorporated herein by reference. The GPC method additionally 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, which is also incorporated herein by reference.

[0124] It should be understood that throughout this disclosure, the terms "comprising", "including", "containing", etc. are considered to be open-ended and include any element, step, or ingredient not expressly listed. The phrase "consisting essentially of" means including any expressly listed element, step, or ingredient and any additional element, step, or ingredient that does not materially affect the basic and novel aspects of the invention. This disclosure also contemplates that any composition described using the terms "comprising", "including", "containing" is also to be interpreted as including the disclosure of the same composition "consisting essentially of its specifically listed components" or "consisting of its specifically listed components".

[0125] Examples

[0126] The following examples are illustrative of the exemplary embodiments of this disclosure. In these examples, as well as elsewhere in this application, all ratios, parts, and percentages are by weight unless otherwise indicated. These examples are presented for illustrative purposes only and are not intended to limit the scope of the invention disclosed herein.

[0127] Example 1

[0128] An oil-soluble hydrocarbon-substituted melamine derivative is prepared by dissolving an alkenyl succinic anhydride (ASA, such as in Table 3 below) in dimethyl sulfoxide at about 100 °C, adding melamine at about 100 °C, and then stirring the reaction mixture for about 5 hours. Then, ice water is added to the mixture, the brown precipitate is collected, and the precipitate is then dissolved in tert-butyl methyl ether, filtered, and then concentrated in a rotary evaporator. The concentrated sample is then dried overnight in an oven at 75 °C to obtain a viscous brown liquid. The alkenyl succinic anhydride (ASA) reactant used in this example is shown in Table 3 below, and the reaction conditions with melamine are shown in Table 4 below.

[0129] Table 3: Alkenyl succinic anhydride (ASA) reactants

[0130] ASA Description A <![CDATA[C that reacts with maleic anhydride 20-24 α-olefin mixture (estimated to be 400 g / mol)]]> B Hexadecenyl (C16) succinic anhydride (322.5 g / mol) C Dodecenyl (C12) succinic anhydride (266.38 g / mol)

[0131] Table 4: Reaction conditions

[0132] Reaction products ASA Molar ratio of ASA: melamine 1 A 2.2:1 2 B 2.5:1 3 C 1.1:1 4 C 3.0:1

[0133] Example 2

[0134] Prepare lubricants containing the reaction products from Table 4 of Example 1 and evaluate their extended copper corrosion according to ASTM D130 (168 hours at 150 °C). Each inventive lubricant of this example contains approximately 0.035 wt% of one of the reaction products from Table 4 of Example 1 and the same amount of the same additive package (e.g., dispersant, antifoaming agent, friction modifier, antioxidant, detergent, and antiwear agent), viscosity modifier, and Group III base oil to form inventive transmission lubricants 1-4 of the present invention having a kinematic viscosity at 100 °C (kV100) (ASTM D445) of approximately 5 cSt. The results of the extended copper corrosion test of the inventive lubricants with ASTM D130 (e.g., visible copper tarnish and copper leaching) are shown in Table 5 below. The extended copper corrosion of comparative lubricants containing the same amounts and the same additive package, viscosity modifier, and Group III base oil but without a corrosion inhibitor was also tested and is shown in Table 5 below for comparison.

[0135] Table 5

[0136] Comparative Example 1 Invention 1 Invention 2 Invention 3 Invention 4 Reaction product 1 (wt%) - 0.035 - - - Reaction product 2 (wt%) - - 0.035 - - Reaction product 3 (wt%) - - - 0.037 - Reaction product 4 (wt%) - - - - 0.035 N ppm from reaction product (calculated) N / A 26.65 33.32 73.29 33.32 Ratio of ASA: melamine N / A 2.2 2.5 1.1 3.0 P, ppm (measured by ICP) 293 282 282 271 284 Visual grade 4b 4a 4b 4a 4a Cu, ppm 59 30 29 32 32

[0137] As shown in Table 5 above, the inventive lubricants containing the melamine derivatives of the present disclosure exhibit comparable or better copper tarnish and lower copper leaching compared to the comparative lubricants. The lubricants of this example do not include any methylbenzotriazole additives or their derivatives.

[0138] Example 3

[0139] Prepare additional inventive lubricants containing the reaction products from Table 4 of Example 1 and evaluate their extended copper corrosion according to ASTM D130 (168 hours at 150 °C) as in Example 2. Each inventive lubricant of this example contains approximately 0.035 wt% of one of the reaction products from Table 4 of Example 1 and the same amount of the same additive package (including dispersant, antifoaming agent, friction modifier, antioxidant, detergent, and antiwear agent), viscosity modifier, and Group III base oil to form inventive transmission lubricants 5-8 of the present invention having a kinematic viscosity at 100 °C (kV100) (ASTM D445) of approximately 5 cSt. The results of the extended copper corrosion test of the inventive lubricants of this example with ASTM D130 (e.g., visible copper tarnish and copper leaching) are shown in Table 6 below. The extended copper corrosion of comparative lubricants containing the same amounts and the same additive package, viscosity modifier, and Group III base oil but without a corrosion inhibitor was also tested and is shown in Table 6 below for comparison.

[0140] Table 6

[0141] Comparative Example 2 Invention 5 Invention 6 Invention 7 Invention 8 Reaction product 1 (wt%) - 0.035 - - - Reaction product 2 (wt%) - - 0.035 - - Reaction product 3 (wt%) - - - 0.037 - Reaction product 4 (wt%) - - - - 0.035 N ppm from reaction product N / A 26.65 33.32 73.29 33.32 Ratio of ASA: melamine N / A 2.2 2.5 1.1 3.0 P, ppm (measured by ICP) 142 139 138 139 139 Visual grade 4c 4b 4a 4a 4a Cu, ppm 114 71 61 67 66

[0142] As shown in Table 6 above, the lubricants of the present invention containing the melamine derivatives of the present disclosure exhibit comparable or better copper tarnish and lower copper leaching compared to the comparative lubricants. The lubricants of this example also do not include any methylbenzotriazole additives or their derivatives.

[0143] It should be noted that unless explicitly and affirmatively limited to one indicator, as used in this specification and the appended claims, the singular forms "a / an" and "the" include plural indicators. Thus, for example, reference to "an antioxidant" includes two or more different antioxidants. As used herein, the term "comprising" and its grammatical variants are intended to be non-limiting, such that the recitation of items in a list does not exclude other similar items that may be substituted or added to the listed items.

[0144] For this specification and the appended claims, unless otherwise indicated, all numbers and other numerical values representing quantities, percentages, or proportions used in the specification and claims shall be understood to be modified in all instances by the term "about". Thus, 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 without attempting to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0145] It should be understood that each component, compound, substituent, or parameter disclosed herein should be construed as being disclosed for use alone or in combination with one or more of each of the other components, compounds, substituents, or parameters disclosed herein.

[0146] It should be further understood that each range disclosed herein should be construed as an express disclosure of each specific value within the disclosed range having the same number of significant digits. Thus, for example, the range of 1 to 4 should be construed as an express disclosure of the values 1, 2, 3, and 4 and any range of such values.

[0147] It should be further understood that each lower limit of each range disclosed herein should be construed 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 disclosed herein. Thus, the present disclosure should be construed as an express disclosure of all ranges derived by combining each lower limit of each range with each upper limit of each range or with each specific value within each range, or by combining each upper limit of each range with each specific value within each range. That is to say, it should be further understood that any range between the endpoint values within the broad ranges is also discussed herein. Thus, the range of 1 to 4 also means ranges such as 1 to 3, 1 to 2, 2 to 4, 2 to 3, etc.

[0148] In addition, a specific amount / value of a component, compound, substituent, or parameter disclosed in this specification or an embodiment should be interpreted as a disclosure of the lower or upper limit of a certain range, and thus can be combined with any other lower or upper limit or specific amount / value of the range of the same component, compound, substituent, or parameter disclosed elsewhere in this disclosure to form a range of that component, compound, substituent, or parameter.

[0149] Although specific embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are not currently foreseen or may not be currently foreseen by the applicant or other skilled artisans in the art may be contemplated. Accordingly, the appended claims, as filed and as they may be amended, are intended to cover all such alternatives, modifications, variations, improvements, and substantial equivalents.

Claims

1. A corrosion inhibitor in the form of an oil-soluble hydrocarbyl-substituted melamine derivative having a structure of Formula I, wherein each of R1, R2, and R3 is independently -NH2, a hydrocarbyl-substituted succinimide group, or a hydrocarbyl-substituted dicarboxylic acid-amide group, and wherein one or both of R1, R2, and R3 are independently the hydrocarbyl-substituted succinimide group or the hydrocarbyl-substituted dicarboxylic acid-amide group, and the remaining R1, R2, and R3 are independently the -NH2 or the hydrocarbyl-substituted dicarboxylic acid-amide.

2. The corrosion inhibitor according to claim 1, wherein the hydrocarbyl substituent of the succinimide group or the dicarboxylic acid-amide group is a C12 to C30 hydrocarbyl group, preferably a C12 to C24 hydrocarbyl group.

3. The corrosion inhibitor according to claim 1, wherein the corrosion inhibitor has from about 5 wt% to about 25 wt% nitrogen.

4. The corrosion inhibitor according to claim 1, wherein the corrosion inhibitor is a reaction product of a hydrocarbyl-substituted succinic acid or anhydride and melamine, wherein the hydrocarbyl-substituted succinic acid or anhydride is in molar excess relative to the melamine, preferably wherein the molar ratio of the hydrocarbyl-substituted succinic acid or anhydride to the melamine is from about 1.1:1 to about 4:1, preferably from about 1.1:1 to about 3:

1.

5. The corrosion inhibitor according to claim 1, wherein one of R1, R2, and R3 is independently the hydrocarbyl-substituted succinimide group or the hydrocarbyl-substituted dicarboxylic acid-amine group, and the remaining two of R1, R2, and R3 are the -NH2 groups.

6. The corrosion inhibitor according to claim 5, wherein two of R1, R2, and R3 are independently the hydrocarbyl-substituted succinimide group or the hydrocarbyl-substituted dicarboxylic acid-amine group, and the remaining one of R1, R2, and R3 is the -NH2 group.

7. The corrosion inhibitor according to claim 1, wherein the oil-soluble hydrocarbyl-substituted melamine derivative has one or more of the following structures: wherein each of their R groups is independently a C12 to C30 hydrocarbyl group.

8. The corrosion inhibitor according to claim 1, wherein a lubricating composition comprising from about 0.1 wt% to about 0.5 wt% of the corrosion inhibitor exhibits less than about 100 ppm of copper after testing for 168 hours at 150 °C according to ASTM D130.

9. A method for preparing an oil-soluble hydrocarbyl-substituted melamine derivative corrosion inhibitor, the method comprising reacting a hydrocarbyl-substituted succinic acid or anhydride with melamine, wherein the hydrocarbyl-substituted succinic acid or anhydride is in molar excess relative to the melamine.

10. The method according to claim 9, wherein the hydrocarbyl substituent is a C12 to C30 hydrocarbyl group, preferably a C12 to C24 hydrocarbyl group.

11. The method according to claim 9, wherein the molar ratio of the hydrocarbyl-substituted succinic acid or anhydride to the melamine is from about 1.1:1 to about 4:1, preferably from about 1.1:1 to about 3:

1.

12. The method according to claim 9, wherein the corrosion inhibitor formed has from about 5 wt% to about 25 wt% nitrogen.

13. The method according to claim 9, wherein the oil-soluble hydrocarbyl-substituted melamine derivative formed has the structure of formula I wherein each of R1, R2, and R3 is independently -NH2, a hydrocarbyl-substituted succinimide group, or a hydrocarbyl-substituted dicarboxylic acid-amide group, and wherein one or two of R1, R2, and R3 are independently the hydrocarbyl-substituted succinimide group or the hydrocarbyl-substituted dicarboxylic acid-amide group, and the remaining R1, R2, and R3 are independently the -NH2 or the hydrocarbyl-substituted dicarboxylic acid-amide.

14. The method according to claim 13, wherein one of R1, R2, and R3 is independently the hydrocarbyl-substituted succinimide group or the hydrocarbyl-substituted dicarboxylic acid-amine group, and the remaining two of R1, R2, and R3 are the -NH2 groups; and / or wherein two of R1, R2, and R3 are independently the hydrocarbyl-substituted succinimide group or the hydrocarbyl-substituted dicarboxylic acid-amine group, and the remaining one of R1, R2, and R3 is the -NH2 group.

15. The method according to claim 9, wherein the oil-soluble hydrocarbyl-substituted melamine derivative has one or more of the following structures: wherein each of their R groups is independently a C12 to C30 hydrocarbyl group.

Images