Powertrain lubricant containing

Abstract

The present technology relates to a lubricant formulation containing a polyether, and in particular wherein the lubricant contains a sulfur source, such as a thiadiazole, and a method for minimizing conductive deposits therewith.

Description

BACKGROUND OF THE INVENTION

[0001] The present technology relates to a lubricant formulation containing polyethers and, in particular, wherein the lubricant contains a sulfur source, such as thiadiazole, and a method for minimizing conductive deposits therewith.

[0002] Powertrains and other devices in electric vehicles typically use oil-based lubricant compositions for lubrication, which are used to lubricate moving parts and carry away heat. Such compositions may contain a lubricating base oil as a main component and one or more lubricating oil additives as secondary components, such as antioxidants, detergents, dispersants, antiwear additives, corrosion inhibitors, viscosity modifiers, metal deactivators, pour point depressants, seal compatibilizers, defoamers, extreme pressure agents, friction improvers, etc. Wires and other current-carrying components of the lubricating device are usually coated or covered to minimize contact with the lubricant composition. However, over time, electrical components may be exposed to the lubricant composition due to wear or thermal damage. For example, copper conductors may overheat, exerting pressure on the coating and causing the coating to fail. When this occurs, the lubricant composition may come into contact with the exposed wire and may form deposits on the wire. Depending on the chemical nature of the deposits, the deposits may be conductive or non-conductive. Conductive deposits are particularly problematic because they can cause current to flow between closely spaced wires and ultimately lead to electrical device failure. In addition, in some components such as circuit boards, the wires may not have a coating. These components may be exposed to the gas phase of the lubricant composition and may also form deposits.

[0003] It is anticipated that certain lubricant additives used alone or in combination may be more likely to cause such deposits in electromechanical devices such as drive trains. In addition, such devices may be exposed to the gas phase of the lubricant, which can result in different types or rates of deposit formation compared to the liquid phase. However, to date, there has been no method to evaluate lubricant compositions under conditions typically experienced in devices operating at relatively high temperatures and using high pressures.

[0004] Lubricating fluids for conventional internal combustion engines typically employ additives to provide sufficient amounts of sulfur and phosphorus to provide wear and extreme pressure protection to mechanical components. However, such additives in lubricating fluids for electric motors or hybrid electric motors can cause problems because active sulfur and phosphorus compounds are generally chemically aggressive to copper wire and copper-based alloys used in electric motors and / or hybrid electric motors. In addition, sulfur and phosphorus compounds are generally conductive, and the inclusion of active sulfur and phosphorus compounds in the lubricant can lead to an undesired increase in the electrical conductivity of the lubricant. Therefore, lubricating fluids for electric and hybrid electric motors have the additional challenge of maintaining a relatively low electrical conductivity while still protecting copper components and providing sufficient protection to mechanical components.

[0005] Generally speaking, it is necessary to implement lubricating compositions (also known as "lubricants") in electric or hybrid vehicles, mainly to reduce the friction between various components of the vehicle propulsion system, especially between the moving metal components in the engine. These lubricating compositions also effectively prevent premature wear or even damage to these components, and especially to their surfaces.

[0006] To this end, lubricating compositions are conventionally composed of one or more base oils and "anti-wear" additives to reduce the wear of engine mechanical components and thus prevent the deterioration of engine durability. There are various anti-wear additives, among which mention may be made, for example, of dimercaptothiadiazole, polysulfides (especially sulfurized olefins), amine phosphates or even phosphorus-sulfur additives such as amine salts of alkyl thiophosphates.

[0007] Unfortunately, when used in lubricants, these amine and / or sulfur anti-wear additives (such as dimercaptothiadiazole and amine (thio)phosphates) have the following disadvantages: they form deposits on wiring (especially copper) when the lubricant comes into contact with electrical components in the transmission of an electric or hybrid vehicle. Conductive deposits are particularly problematic because they can cause current to flow between closely spaced wires and ultimately lead to electrical device failures. Deposit formation is particularly critical in electric propulsion systems. In particular, such deposit formation can lead to a risk of damage to the windings of the stator and rotor, to the sensors in the propulsion system, to the solenoid valves in the hydraulic system, and to the bearings (usually copper-based and thus particularly sensitive to corrosion) located between the rotor and stator of the electric motor or to the seals or varnishes present in the propulsion system.

[0008] WO PCT patent applications WO2020260458A1, WO2020260457A1, WO2020260462A1 and WO2020260460A1 disclose the use of benzotriazole, succinimide, hindered aromatic amines or phenols and phosphorus compounds free of sulfur and amine together with amine salts and / or sulfur anti-wear additives to minimize copper corrosion. These methods involve measuring the loss of the diameter of copper wire by the change in the resistance value when the copper wire is immersed in the lubricating fluid. These methods do not solve the problem of deposit formation (especially conductive deposits on copper components in the propulsion system of a hybrid or electric vehicle when amine salts and / or sulfur anti-wear agents are present in the lubricant).

[0009] U.S. Patent US11,326,123 discloses a durable lubricating fluid for an electric motor or a hybrid electric motor. The disclosed technology relates to a durable (measured by conductivity durability) lubricating fluid that contains an oil having lubricating viscosity, a thiadiazole or its derivative, an amine salt of a phosphate ester, and has a sulfur plus phosphorus to nitrogen ((S+P) / N)) weight ratio of at least 2.3 and at least 2000 ppm of sulfur provided by the thiadiazole compound. The focus of this patent is on the durability of the conductivity of the lubricating fluid and does not mention the copper corrosion problem caused by the thiadiazole and the amine salt of the phosphate ester.

[0010] Accordingly, there is a need for a lubricant formulation, particularly in the form of a sulfur-containing lubricant, for preventing conductive deposits. SUMMARY OF THE INVENTION

[0011] In one embodiment, the disclosed technology solves the problem of conductive deposits by preparing a formulation containing a polyether.

[0012] Thus, one aspect of the present technology includes a lubricant composition that comprises: an oil having lubricating viscosity, an amine (thio)phosphate, and 0.5 wt% to 10.0 wt% of a polyether.

[0013] The polyether can include, for example, those of formula I:

[0014]

[0015] wherein R1 can be a hydrocarbon group having 6 to 30 carbon atoms, R2 can be hydrogen or an alkyl group having 1 to 5 carbon atoms, and R3 can be hydrogen, a C1-C4 alkyl group, or -C(O)R4, and wherein R4 can be a C1-C4 alkyl group, and x can be an integer from 10 to 40 (15 to 35 or 20 to 30 or 22 to 26).

[0016] The polyether can also include those of formula II:

[0017]

[0018] wherein R5 can be a straight-chain or branched aliphatic group having 1 to 30 carbon atoms, in another embodiment 10 to 20 carbon atoms, R2 can be hydrogen or an alkyl group having 1 to 5 carbon atoms, and R3 can be hydrogen, a C1-C4 alkyl group, -C(O)R4, where R4 can be a C1-C4 alkyl group, and n can be an integer from 10 to 40 (15 to 35 or 20 to 30 or 22 to 26), and m can be an integer from 1 to 3.

[0019] The polyether also includes those of formula III:

[0020]

[0021] Wherein the hydrocarbyl group R1 can be a straight-chain or branched aliphatic group having 7 to 23 carbon atoms, R2 can be hydrogen or an alkyl group having 1 to 5 carbon atoms, and R3 can be hydrogen, a C1-C4 alkyl group or -C(O)R4, and wherein R4 can be a C1-C4 alkyl group, and n can be an integer from 10 to 40 (15 to 35 or 20 to 30 or 22 to 26), and m can be an integer from 1 to 3.

[0022] In some cases, the lubricant may also contain thiadiazoles, such as 1,3,4-thiadiazole or 2,5-thiadiazole.

[0023] The lubricant may also contain other common additives known in the art, such as dispersants, antioxidants, dispersant viscosity modifiers, detergents, antiwear additives, and the like.

[0024] The present technology also includes a method for minimizing conductive deposits in the propulsion system of an electric or hybrid vehicle. The method includes: applying a lubricant as discussed herein to the propulsion system, and operating the propulsion system. Detailed Description

[0025] Various preferred features and embodiments will be described below in a non-limiting manner.

[0026] The present technology provides a method for minimizing conductive deposits in the propulsion system of an electric or hybrid vehicle by applying a lubricant containing an oil having lubricating viscosity, a polyether, and an amine (thio) phosphate to the propulsion system.

[0027] The lubricating composition includes an oil having lubricating viscosity. Such oils include natural oils and synthetic oils, oils derived from hydrocracking, hydrogenation, and hydrofinishing, unrefined oils, refined oils, re-refined oils, or mixtures thereof. More detailed descriptions of unrefined, refined, and re-refined oils are provided in paragraphs

[0054] to

[0056] of International Publication W02008 / 147704 (similar disclosures are provided in U.S. Patent Publication 2010 / 0197536, see

[0072] to

[0073] ). More detailed descriptions of natural lubricating oils and synthetic lubricating oils are described in paragraphs

[0058] to

[0059] of W02008 / 147704, respectively (similar disclosures are provided in U.S. Patent Publication 2010 / 0197536, see

[0075] to

[0076] ). Synthetic oils can also be produced by the Fischer-Tropsch reaction and can generally be hydroisomerized Fischer-Tropsch hydrocarbons or waxes. In one embodiment, the oil can be prepared by a Fischer-Tropsch gas-to-liquid synthesis process as well as other gas-to-liquid oils.

[0028] An oil having lubricating viscosity can also be defined as specified in subtitle 1.3 of subsection 1.3 of the April 2008 edition of “Appendix E - API Base Oil Interchangeability Guidelines for Passenger Car Motor Oils and Diesel Engine Oils”. It is defined according to the provisions of “Base Stock Categories”. The API guidelines are also outlined in U.S. Patent No. 7,285,516 (see column 11, line 64 to column 12, line 10). In one embodiment, the oil having lubricating viscosity can be an API Group II, III, or IV oil or a mixture thereof. The five base oil classifications are as follows:

[0029]

[0030] The amount of the oil having lubricating viscosity is generally the balance remaining after subtracting the sum of the amounts of the compounds of the present invention and other performance additives from 100 weight percent (wt%).

[0031] The lubricating composition can be in the form of a concentrate and / or in the form of a fully formulated lubricant. If the lubricating composition of the present invention (comprising the additives disclosed herein) is in the form of a concentrate that can be combined with additional oil to form all or part of a finished lubricant, the ratio of these additives to the oil having lubricating viscosity and / or diluent oil includes a range of 1:99 to 99:1 by weight or 80:20 to 10:90 by weight.

[0032] In one embodiment, the kinematic viscosity of the base oil at 100 °C is 2 mm2 / s (centi Stokes - cSt) to 16 mm2 / s, 3 mm2 / s to 10 mm2 / s, or even 4 mm2 / s to 8 mm2 / s.

[0033] The ability of the base oil to act as a solvent (i.e., solvency) can be a factor in increasing the frequency of LSPI events during the operation of a direct injection fuel engine. The solvency of the base oil can be measured by the ability of the base oil without additives as a solvent for polar components. Generally, as the base oil category transfers from Group I to Group IV (PAO), the solvency of the base oil decreases. That is, for oils of a given kinematic viscosity, the solvency of the base oil can be ranked as follows: Group I > Group II > Group III > Group IV. The solvency of the base oil also decreases with an increase in viscosity within a base oil category; low-viscosity base oils tend to have better solvency than similar higher-viscosity base oils. The solvency of the base oil can be measured by the aniline point (ASTM D611).

[0034] In one embodiment, the base oil comprises at least 30 wt% of Group II or Group III base oil. In another embodiment, the base oil comprises at least 60 wt% of Group II or Group III base oil, or at least 80 wt% of Group II or Group III base oil. In one embodiment, the lubricant composition comprises less than 20 wt% of Group IV (i.e., polyalphaolefin) base oil. In another embodiment, the base oil comprises less than 10 wt% of Group IV base oil. In one embodiment, the lubricating composition is substantially free (i.e., comprises less than 0.5 wt%) of Group IV base oil.

[0035] Ester-based fluids, known as Group V oils, have a very high level of solvency due to their polar nature. Adding a low content (typically less than 10 wt%) of esters to a lubricant composition can significantly increase the solvency of the resulting base oil mixture. Esters can be broadly classified into two categories: synthetic esters and natural esters. Ester-based fluids have a kinematic viscosity at 100 °C suitable for engine oil lubricants, such as between 2 cSt and 30 cSt, or 3 cSt to 20 cSt, or even 4 cSt to 12 cSt.

[0036] Synthetic esters can include esters of dicarboxylic acids (e.g., phthalic acid, succinic acid, alkyl succinic acid and alkenyl succinic acid, maleic acid, azelaic acid, suberic acid, sebacic acid, fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkyl malonic acid and alkenyl malonic acid) with any of a variety of monohydric alcohols (e.g., butanol, hexanol, dodecanol, 2-ethylhexanol, ethylene glycol, diethylene glycol monoether and propylene glycol). Specific examples of these esters include dibutyl adipate, bis(2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate, bisicosyl sebacate, 2-ethylhexyl diester of linoleic acid dimer and a complex ester formed by reacting 1 mole of sebacic acid with 2 moles of tetraethylene glycol and 2 moles of 2-ethylhexanoic acid. Other synthetic esters include esters prepared from C5 to C12 monocarboxylic acids and polyhydric alcohols and polyhydric alcohol ethers (such as neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol and tripentaerythritol). Esters can also be monoesters of monocarboxylic acids and monohydric alcohols.

[0037] Natural (or bio-derived) esters refer to substances derived from renewable biological resources, organisms, or entities, which are different from substances derived from petroleum or equivalent raw materials. Natural fats include fatty acid triglycerides, hydrolyzed or partially hydrolyzed triglycerides, or transesterified triglycerides, such as fatty acid methyl esters (or referred to as FAME). Suitable triglycerides include, but are not limited to, palm oil, soybean oil, sunflower oil, rapeseed oil, olive oil, linseed oil, and related substances. Other sources of triglycerides include, but are not limited to, algae, animal fats, and zooplankton. Methods for producing bio-lubricants from natural triglycerides are described, for example, in U.S. Patent Publication No. 2011 / 0009300A1.

[0038] In one embodiment, the lubricant composition may comprise at least 2 wt% of an ester-based fluid. In one embodiment, the lubricating composition of the present invention comprises at least 4 wt% of an ester-based fluid, or at least 7 wt% of an ester-based fluid, or even at least 10 wt% of an ester-based fluid.

[0039] Polyethers can be prepared by condensing an alcohol, a hydrocarbyl carboxylic acid, or an alkylphenol with an alkylene oxide, a mixture of alkylene oxides, or in a sequential manner with several alkylene oxides at a molar ratio of hydrogen-containing compound to alkylene oxide of 1:2 to 50 to form a polyether. U.S. Patent No. 5,094,667 provides reaction conditions for preparing polyethers, the disclosure of which is incorporated herein by reference. Examples of alkylene oxides include ethylene oxide, propylene oxide, or butylene oxide. The number of alkylene oxide units in the polyether intermediate can be from 10 to 35 or from 18 to 27.

[0040] In one embodiment, the polyether for the lubricant can be prepared from a primary alcohol. Suitable primary alcohols for use herein can contain from 6 to 30 carbon atoms, in another embodiment from 8 to 24 or from 10 to 20 carbon atoms. Mixtures of alcohols are contemplated. In one embodiment, the alcohol mixture used is at least 50 wt%, or at least 60 wt%, or at least 80 wt% or at least 90 wt% of an alcohol having at least 10 aliphatic carbon atoms or at least 12 aliphatic carbon atoms. In one embodiment, the alcohol mixture used contains no more than 5.0 wt%, or no more than 2 wt% or no more than 1 wt% of C6 and lower straight-chain alcohols.

[0041] The primary alcohol can be straight-chain or branched at the α-position, or β-position, or higher positions, provided that there are no more than 3 branching points, or no more than 2 branching points or no more than 1 branching point. In one embodiment, a mixture of straight-chain and branched-chain alcohols is employed.

[0042] Examples of available primary linear alcohols include decanol, dodecanol, tridecanol, tetradecanol, pentadecanol, hexadecanol, heptadecanol, octadecanol, nonadecanol, eicosanol, or mixtures thereof. In one embodiment, the linear alcohol contains 10 to 30, or 10 to 25, or 12 to 22 carbon atoms (typically 10 to 22 carbon atoms).

[0043] Other exemplary primary alcohols include commercially available alcohol mixtures. These include oxoalcohols, which can comprise various mixtures of alcohols having, for example, 8 to 24 carbon atoms. Among the various commercial alcohols available herein, there are 12 to 18 aliphatic carbon atoms. The alcohols in the mixture can include, for example, one or more of octanol, nonanol, decanol, undecanol, dodecanol, tetradecanol, pentadecanol, and octadecanol. Several suitable sources of these alcohol mixtures are the industrial grade alcohols sold under the name alcohol (Shell Oil Company, Houston, Tex.), and the industrial grade alcohols sold under the name alcohol (Sasol, Westlake, La.), as well as fatty alcohols derived from animal fats and vegetable fats and sold by, for example, Henkel, Sasol, and Emery.

[0044] In some embodiments, the alcohol includes one or more Guerbet alcohols. Guerbet alcohols can be described as alcohols made via the Guerbet reaction, named after Marcel Guerbet. In the Guerbet reaction, a primary fatty alcohol is converted to its β-alkylated dimer alcohol (i.e., a branched primary saturated alcohol). In some embodiments, the alcohol includes at least one compound with the following structure: HO—CH2—(R1)n—CR2R3R4, where R1 is an alkylene group containing 1 to 20 carbon atoms, n is 0 or 1, and each of R2, R3, and R4 is independently hydrogen or an alkyl group containing 1 to 20 carbon atoms. In some embodiments, n is zero, and R2 and R3 are alkyl groups, and R4 is hydrogen. In such embodiments, R2 and R3 can contain 4 to 14 or even 6 to 12 carbon atoms. In additional embodiments, R2 and R3 contain 6 and 8 or 10 and 12 carbon atoms. Suitable examples of alcohols useful in the present invention include 2-ethylhexanol, 2-butyl octanol, 2-hexyl decanol, 2-octyl dodecanol, 2-decyl tetradecanol, 2-dodecyl hexadecanol, or any combination thereof. These types of alcohols are commercially available from Sasol and are sold as Alcohol sales. In some embodiments, the alcohol includes 2-hexyldecanol, 2-decyltetradecanol, or any combination thereof. In some embodiments, the alcohol includes 2-hexyldecanol. In some embodiments, the alcohol includes 2-decyltetradecanol.

[0045] In another embodiment, the alcohol can be an alcohol with an isoalkyl group. The isoalkyl group is an atomic group obtained by removing a hydrogen atom from a methyl group located at the end of the straight-chain segment of an isoalkane. Particularly useful alcohols with an isoalkyl group are those in which the methyl group is attached to the penultimate carbon atom of the main chain. Exemplary alcohols of this type are isodecanol, isododecanol, isotridecanol, isotetradecanol, isopentadecanol, isohexadecanol, isoheptadecanol, isooctadecanol, isononadecanol, isoeicosanol.

[0046] In one embodiment, the polyether can have the following formula

[0047]

[0048] wherein R1 is a hydrocarbon group having 6 to 30 carbon atoms, R2 is hydrogen or an alkyl group having 1 to 5 carbon atoms, and R3 is hydrogen, a C1-C4 alkyl group, or -C(O)R4, and wherein R4 is a C1-C4 alkyl group, and x is an integer from 10 to 40 (15 to 35 or 20 to 30 or 22 to 26).

[0049] In one embodiment, for the polyether of formula I, the hydrocarbon group R1 is a straight-chain aliphatic group having 6 to 30 carbon atoms, in another embodiment 8 to 24 or 10 to 20 carbon atoms, and in yet another embodiment 10 to 18 carbon atoms.

[0050] In one embodiment, for the polyether of formula I, the hydrocarbon group R1 is a branched-chain aliphatic group having 6 to 30 carbon atoms, in another embodiment 8 to 24 or 10 to 20 carbon atoms, and in yet another embodiment 10 to 18 carbon atoms.

[0051] In one embodiment, for the polyether of formula I, the hydrocarbon group R1 is a straight-chain aliphatic group having 6 to 30 carbon atoms, in another embodiment 8 to 24 or 10 to 20 carbon atoms, and in yet another embodiment 10 to 18 carbon atoms, and R3 is hydrogen

[0052] In one embodiment, for the polyether of formula I, the hydrocarbon group R1 is a branched-chain aliphatic group having 6 to 30 carbon atoms, in another embodiment 8 to 24 or 10 to 20 carbon atoms, and in yet another embodiment 10 to 18 carbon atoms, and R3 is hydrogen

[0053] In various embodiments, the polyether of formula I is present in an amount ranging from 0.01 wt% to 2 wt%, or 0.02 wt% to 1 wt%, or 0.04 wt% to 0.6 wt%, or even 0.25 wt% to 0.5 wt% of the lubricating composition. Generally, the polyether of formula I is present in an amount of 0.05 wt% to 1 wt% of the lubricating composition.

[0054] In one embodiment, the polyether is prepared from an alkylphenol. The alkyl group of the alkylphenol can be from 1 to 30 carbon atoms, and in another embodiment, from 10 to 20 carbon atoms.

[0055] In some embodiments, the polyether may include an alkoxylated hydrocarbyl phenol represented by formula II:

[0056]

[0057] wherein each R2 is independently hydrogen or a hydrocarbyl group of 1 to 6 carbon atoms; R3 is hydrogen, a C1-C4 alkyl group, -C(=O)R4, where R4 is a C1-C4 alkyl group. In some embodiments, each R5 of formula II is from 1 to 24 carbon atoms; from 10 to 24 (such as 12 to 24, 14 to 24, 16 to 24, 18 to 24, 20 to 24, 22 to 24, 10 to 22, 12 to 22, 14 to 22, 16 to 22, 18 to 22, 20 to 22, 10 to 20, 12 to 20, 14 to 20, 16 to 20, 18 to 20, 10 to 18, 12 to 18, 14 to 18, 16 to 18, 10 to 16, 12 to 16, 14 to 16, 10 to 14, 12 to 14, or 10 to 12) carbon atoms of a hydrocarbyl group.

[0058] An alkoxylated hydrocarbyl phenol of formula II, wherein the R2 group is methyl, R3 is hydrogen, an alkyl group having 1 to 4 carbon atoms or an acyl group represented by -C(=O)R4, R4 is an alkyl group having 1 to 4 carbon atoms; R5 is an aliphatic hydrocarbyl group having 10 to 24 (such as 12 to 24, 14 to 24, 16 to 24, 18 to 24, 20 to 24, 22 to 24, 10 to 22, 12 to 22, 14 to 22, 16 to 22, 18 to 22, 20 to 22, 10 to 20, 12 to 20, 14 to 20, 16 to 20, 18 to 20, 10 to 18, 12 to 18, 14 to 18, 16 to 18, 10 to 16, 12 to 16, 14 to 16, 10 to 14, 12 to 14 or 10 to 12) carbon atoms, n = 2 to 8 (or 3 to 5); and m = 1.

[0059] The R5 group of each of the above formula II can be located in the para position relative to the alkoxylated group, and the resulting formula is represented by the following structure:

[0060]

[0061] wherein the variables R2 to R5 and n are as previously defined.

[0062] In one embodiment, an alkoxylated hydrocarbyl phenol of formula II is selected such that the R2 group is methyl, R3 is hydrogen, an alkyl group having 1 to 4 carbon atoms or an acyl group represented by -C(=O)R4, R4 is an alkyl group having 1 to 4 carbon atoms; R5 is an aliphatic hydrocarbyl group having 10 to 24 (such as 12 to 24, 14 to 24, 16 to 24, 18 to 24, 20 to 24, 22 to 24, 10 to 22, 12 to 22, 14 to 22, 16 to 22, 18 to 22, 20 to 22, 10 to 20, 12 to 20, 14 to 20, 16 to 20, 18 to 20, 10 to 18, 12 to 18, 14 to 18, 16 to 18, 10 to 16, 12 to 16, 14 to 16, 10 to 14, 12 to 14 or 10 to 12) carbon atoms, n = 2 to 8 (or 3 to 5); and m = 1.

[0063] In one embodiment, the alkoxylated hydrocarbyl phenol of the present invention is represented by formula II(b)

[0064]

[0065] Wherein R5 can be a straight-chain or branched aliphatic group having 1 to 30 carbon atoms, in another embodiment 10 to 20 carbon atoms, R2 can be hydrogen or an alkyl group having 1 to 5 carbon atoms, and R3 can be hydrogen, a C1-C4 alkyl group, -C(O)R4, wherein R4 can be a C1-C4 alkyl group, and n can be an integer from 10 to 40 (15 to 35 or 20 to 30 or 22 to 26), and m can be an integer from 1 to 3.

[0066] The alkoxylated group of the alkoxylated hydrocarbyl phenol has the formula —(R1O)n—, wherein R1 is an ethylene, propylene, butylene group or a mixture thereof; and n can independently be 1 to 50, or 1 to 20, or 1 to 10 or 2 to 5.

[0067] The alkoxylated group of the alkoxylated hydrocarbyl phenol can be its homopolymer or copolymer or oligomer. If the alkoxylated group is in the form of its copolymer or oligomer, the alkoxylated group can have a random or block architecture.

[0068] In one embodiment, the alkoxylated group (or R1) is a propylene or butylene group, i.e., the alkoxylated group does not require an ethylene group. If an ethylene group is present, the alkoxylated group can be its copolymer or oligomer with propylene oxide or butylene oxide, i.e., a block of (i) —CH2CH2O— and (ii) —CH2CH2CH2CH2O— or —CH2CH(CH3)CH2O— or —CH2CH(CH3)O—.

[0069] In one embodiment, the alkoxylated group is based on propylene oxide.

[0070] The alkoxylated hydrocarbyl phenol can be prepared by reacting a hydrocarbyl-substituted phenol with an alkylene oxide (usually ethylene oxide, propylene oxide or butylene oxide), optionally in the presence of a base catalyst. Usually, the reaction is carried out in the presence of a base catalyst.

[0071] The base catalyst can include but is not limited to sodium chloroacetate, sodium hydride or potassium hydroxide.

[0072] The aliphatic hydrocarbyl group (also denoted by R4) is straight-chain or branched and usually has at least one branching point. The aliphatic hydrocarbyl group usually has one, although in some embodiments it may be desirable to have an R4 group wherein the second group is a methyl group. If the second R4 group is present and is a methyl group, the alkoxylated hydrocarbyl phenol is cresol.

[0073] In various embodiments, the alkoxylated hydrocarbyl phenol of the present invention is present in the lubricating composition in an amount of from 0.01 wt% to 5 wt%, or from 0.05 wt% to 3.5 wt%, or from 0.1 wt% to 2.5 wt%. Generally, the polyether of formula I is present in the lubricating composition in an amount of from 0.25 wt% to 2 wt%.

[0074] In one embodiment, the polyether is prepared from a hydroxycarboxylic acid having from 8 to 24 carbon atoms, in another embodiment from 12 to 24 carbon atoms, and in yet another embodiment from 14 to 18 carbon atoms.

[0075] In some embodiments, the polyether may include an alkoxylated hydrocarbyl phenol represented by formula III:

[0076]

[0077] wherein the hydrocarbyl group R1 is a straight or branched aliphatic group having from 7 to 23 carbon atoms, in another embodiment from 11 to 23 or 13 to 17 carbon atoms, R2 is hydrogen or an alkyl group having from 1 to 5 carbon atoms, and R3 is hydrogen, a C1-C4 alkyl group or -C(O)R4, R4 is a C1-C4 alkyl group, and n is an integer from 10 to 40 (15 to 35 or 20 to 30 or 22 to 26), and m is an integer from 1 to 3.

[0078] Examples of alkoxylated hydrocarbyl carboxylic acids include, but are not limited to, tall oil fatty acid-initiated poly(propylene oxide)(22 - 24) ester alcohol, butanol-initiated poly(propylene oxide)(23 - 25) ether tallow fatty acid ester, and tallow fatty acid-initiated poly(propylene oxide)(22 - 24) ester alcohol. These alkoxylates can be prepared by the reaction of a fatty acid such as tall oil fatty acid (TOFA) (i.e., a fatty acid mixture mainly consisting of oleic acid and linoleic acid and containing residual abietic acid or butyric acid, i.e., a fatty acid mixture mainly consisting of stearic acid, palmitic acid and oleic acid) with an alcohol-terminated polyether such as polypropylene glycol in the presence of an acidic catalyst, typically methanesulfonic acid. These alkoxylates can also be prepared by the reaction of glycerol dioleate and propylene oxide in the presence of a catalyst.

[0079] The lubricant in the method contains an oil-soluble amine salt or amine adduct of a phosphate ester, such as those taught in U.S. Pat. Nos. 5,354,484, 5,763,372, and 5,942,470. The amine salt or adduct of the phosphate ester can be prepared by reacting the phosphate ester with ammonia or a basic nitrogen compound such as an amine. The salt can be formed separately and subsequently the salt of the phosphate ester can be added to the lubricating composition. The phosphate ester useful for preparing the amine salt of the present invention can be characterized by the following formula:

[0080]

[0081] wherein R1 is hydrogen or a hydrocarbon group, R2 is a hydrocarbon group, and both X groups are O or S.

[0082] A preferred method for preparing a composition containing (I) comprises reacting at least one hydroxy compound of the formula ROH with a phosphorus compound of the formula P2X5, where R is a hydrocarbon group and X is O or S. The phosphorus-containing composition obtained in this way is a mixture of phosphorus compounds and is generally a mixture of mono- and dihydrocarbyl-substituted phosphoric acids and / or dithiophosphoric acids depending on the choice of the phosphorus reactant (i.e., P2O5 or P2S5). The hydroxy compound used for preparing the phosphate esters of the present invention is characterized by the formula ROH, where R is a hydrocarbon group. The hydroxy compound reacting with the phosphorus compound may include a mixture of hydroxy compounds of the formula ROH, where the hydrocarbon group R contains from about 1 to 40 carbon atoms. However, it is necessary that the amine salt of the finally prepared substituted phosphate ester be soluble in the lubricating composition of the present invention. Generally, the R group will contain at least 2 carbon atoms, usually 4 to 40, or 6 to 39, or 6 to 18 or 8 to 18 carbon atoms. The R group may be aliphatic or aromatic, such as alkyl, aryl, alkaryl, aralkyl, and cycloaliphatic hydrocarbon groups. Examples of available hydroxy compounds of the formula ROH include, for example, ethanol, isopropanol, n-butanol, pentanol, hexanol, 2-ethyl-hexanol, nonanol, dodecanol, stearyl alcohol, amylphenol, octylphenol, nonylphenol, methylcyclohexanol, alkylated naphtha, etc.

[0083] Preferred alcohols ROH are fatty alcohols and more particularly primary fatty alcohols containing at least about 4 carbon atoms. Thus, examples of preferred monohydric alcohols ROH useful in the present invention include pentanol, 1-octanol, 1-decanol, 1-dodecanol, 1-tetradecanol, 1-hexadecanol, 1-octadecanol, oleyl alcohol, linoleyl alcohol, linolenyl alcohol, phytol, melissyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, and docosanol. Commercial alcohols (including mixtures) are contemplated herein, and these commercial alcohols may include trace amounts of alcohols that do not detract from the main object of the present invention (although not stated herein).

[0084] The amine salts of the present invention can be prepared by reacting the above phosphate esters (such as those represented by formula I) with at least one amino compound, which can be a primary amine, secondary amine, tertiary amine, or a mixture thereof. The amine can be aliphatic, or cyclic, aromatic or non-aromatic, and is generally aliphatic. In one embodiment, the amine includes aliphatic amines, such as aliphatic tertiary amine-primary amine.

[0085] Examples of suitable primary amines include ethylamine, propylamine, butylamine, 2-ethylhexylamine, bis-(2-ethylhexyl)amine, octylamine, and dodecylamine, as well as fatty amines such as n-octylamine, n-decylamine, n-dodecylamine, n-tetradecylamine, n-hexadecylamine, n-octadecylamine, and oleylamine. Other available fatty amines include commercially available fatty amines such as amines (products available from Akzo Chemicals, Chicago, Ill.), such as Armeen C, Armeen 0, Armeen OL, Armeen T, Armeen HT, Armeen S, and Armeen SD, where the letter designations are related to fatty groups (such as coconut oil groups, oleyl groups, tallow groups, or stearyl groups).

[0086] Examples of suitable secondary amines include dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, methylethylamine, ethylbutylamine, N-methyl-1-aminocyclohexane, 2C, and ethylpentylamine. The secondary amine can be a cyclic amine, such as piperidine, piperazine, and morpholine. Examples of tertiary amines include tri-n-butylamine, tri-n-octylamine, tridecylamine, trilaurylamine, tricetylamine, and dimethyloleylamine ( DMOD).

[0087] In one embodiment, the amine is in the form of a mixture. Examples of suitable amine mixtures include (i) tertiary alkyl primary amines having 11 to 14 carbon atoms, (ii) tertiary alkyl primary amines having 14 to 18 carbon atoms, or (iii) tertiary alkyl primary amines having 18 to 22 carbon atoms. Other examples of tertiary alkyl primary amines include tert-butylamine, tert-hexylamine, tert-octylamine (such as 1,1-dimethylhexylamine), tert-decylamine (such as 1,1-dimethyloctylamine), tert-dodecylamine, tert-tetradecylamine, tert-hexadecylamine, tert-octadecylamine, tert-tetracosylamine, and tert-octacosylamine.

[0088] In one embodiment, the available amine mixture is " SIR" or " JMT". SIR and JMT (both produced and sold by Rohm & Haas) are mixtures of C11 to C14 tertiary alkyl primary amines and C18 to C22 tertiary alkyl primary amines, respectively.

[0089] In one embodiment, the lubricating composition contains a phosphorus compound, which can be an amine salt of a phosphoric acid ester hydrocarbon ester (i.e., an amine salt of a hydrocarbon ester of phosphoric acid). The amine salt of the phosphoric acid ester hydrocarbon ester can be derived from an amine salt of phosphate. The amine salt of the phosphoric acid ester hydrocarbon ester can be represented by the following formula:

[0090]

[0091] Wherein R3 and R4 can independently be hydrogen or a hydrocarbon usually containing 4 to 40, or 6 to 30, or 6 to 18 or 8 to 18 carbon atoms, provided that at least one is a hydrocarbon group; and R5, R6, R7 and R8 can independently be hydrogen or a hydrocarbon group, provided that at least one is a hydrocarbon group. The hydrocarbon group of R3 and / or R4 can be straight-chain, branched-chain or cyclic. Examples of the hydrocarbon group of R3 and / or R4 include straight-chain or branched-chain alkyl groups, including methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl and octadecyl.

[0092] Examples of the cyclic hydrocarbon group of R3 and / or R4 include cyclopentyl, cyclohexyl, cycloheptyl, methylcyclopentyl, dimethylcyclopentyl, methylcyclopentyl, dimethylcyclopentyl, methylethylcyclopentyl, diethylcyclopentyl, methylcyclohexyl, dimethylcyclohexyl, methylethylcyclohexyl, diethylcyclohexyl, methylcycloheptyl, dimethylcycloheptyl, methylethyl-cycloheptyl and diethylcycloheptyl.

[0093] In another embodiment, the phosphorus antiwear / extreme pressure agent can be dithiophosphoric acid or phosphorodithioic acid. The dithiophosphoric acid can be represented by the formula (RO)2PSSH, wherein each R is independently a hydrocarbon group containing about 3 to about 30 carbon atoms. R usually contains up to about 18, or up to about 12 or up to about 8 carbon atoms. Examples of R include isopropyl, isobutyl, n-butyl, sec-butyl, various pentyls, n-hexyl, methylisobutyl, carbonyl, heptyl, 2-ethylhexyl, isooctyl, nonyl, docosyl, decyl, dodecyl and tridecyl groups. Exemplary lower alkylphenyl R groups include butylphenyl, pentylphenyl, heptylphenyl, etc. Examples of mixtures of R groups include: 1-butyl and 1-octyl; 1-pentyl and 2-ethyl-l-hexyl; isobutyl and n-hexyl; isobutyl and isopentyl; 2-propyl and 2-methyl-4-pentyl; isopropyl and sec-butyl; and isopropyl and isooctyl.

[0094] In one embodiment, the dithiophosphoric acid can react with an epoxide or a diol. This reaction product can be used alone or further reacted with phosphoric acid, an acid anhydride, or a lower ester. The epoxide is generally an aliphatic epoxide or styrene oxide. Examples of available epoxides include ethylene oxide, propylene oxide, butylene oxide, octylene oxide, dodecylene oxide, styrene oxide, etc. Propylene oxide is preferred. The diol can be an aliphatic diol having 1 to about 12, or 2 to about 6, or 2 or 3 carbon atoms, or an aromatic diol. Diols include ethylene glycol, propylene glycol, catechol, resorcinol, etc. The dithiophosphoric acid, diol, epoxide, inorganic phosphorus reagent, and their reaction methods are described in U.S. Patent Nos. 3,197,405 and 3,544,465, the disclosures of which are incorporated herein by reference. The following Examples B-1 and B-2 illustrate the preparation of available phosphate esters.

[0095] Example B-1

[0096] Phosphorus pentoxide (64 g) was added to 514 g of hydroxypropyl O,O-bis(4-methyl-2-pentyl) dithiophosphate (prepared by reacting bis(4-methyl-2-pentyl)-dithiophosphoric acid with 1.3 moles of propylene oxide at 25 °C) over a period of 45 minutes at 58 °C. The mixture was heated at 75 °C for 2.5 hours, mixed with diatomaceous earth, and filtered at 70 °C. The filtrate contained 11.8 wt% phosphorus, 15.2 wt% sulfur, and had an acid value of 87 (bromophenol blue).

[0097] Example B-2

[0098] A mixture of 667 g of phosphorus pentoxide, 3514 g of diisopropyl dithiophosphoric acid, and the reaction product of 986 g of propylene oxide at 50 °C was heated at 85 °C for 3 hours and filtered. The filtrate contained 15.3 wt% phosphorus, 19.6 wt% sulfur, and had an acid value of 126 (bromophenol blue).

[0099] The acidic phosphate ester can be reacted with ammonia, an amine compound, or a metal base to form an ammonium or metal salt. The salt can be formed separately and then the salt of the phosphate ester can be added to the lubricating composition. Alternatively, the salt can also be formed in situ when the acidic phosphate ester is blended with other components to form a fully formulated lubricating composition.

[0100] The amine salt of the phosphate ester can be formed from ammonia or an amine (including monoamines and polyamines). The amine can be a primary, secondary, or tertiary amine. In one embodiment, the amine is one or more of the amines described above for the preparation of dithiocarbamates. Available amines include those disclosed in U.S. Patent No. 4,234,435, columns 21, line 4 to column 27, line 50, these paragraphs being incorporated herein by reference.

[0101] Monoamines generally contain from 1 to about 24 carbon atoms, or up to about 12 or up to about 6 carbon atoms. Examples of monoamines include methylamine, ethylamine, propylamine, butylamine, octylamine, dodecylamine, and dimethylamine, diethylamine, dipropylamine, dibutylamine, methylbutylamine, ethylhexylamine, trimethylamine, tributylamine, methyldiethylamine, ethyldibutylamine, etc.

[0102] In one embodiment, the amine can be a fatty (C4_30) amine, which includes n-hexylamine, n-octylamine, n-decylamine, n-dodecylamine, n-tetradecylamine, n-hexadecylamine, n-octadecylamine, oleylamine, etc. Other available fatty amines include commercially available fatty amines, such as "Armeen" amines (products available from Armak Chemicals, Chicago, Ill.), such as Armak's Armeen C, Armeen-O, Armeen-OL, Armeen-T, Armeen-HT, Armeen S and Armeen SD, where the letter designations are related to fatty groups (such as coconut oil groups, oleyl groups, tallow groups or soybean groups).

[0103] In one embodiment, the phosphorus antiwear agent can be an amine salt containing a substance represented by formula (I) or (II):

[0104]

[0105] The phosphoamine salt is prepared or can be prepared by: reacting phosphorus pentoxide with a secondary alcohol having from about 3 to about 12 carbon atoms, and reacting the product with a hydrocarbylamine. The hydrocarbylamine can contain at least one C1-C20, C4-C18 or C6-C14 hydrocarbyl group. In the reaction for preparing the alkyl phosphate amine salt, phosphorus pentoxide can be reacted with from about 2.2 moles to about 3.1 moles, or about 2.3 moles to about 2.8 moles or 2.4 to 2.4 moles of secondary alcohol per mole of P2O5 at a temperature of about 30 °C to about 60 °C.

[0106] The alkyl phosphate amine salt can contain up to about 60 mol% of phosphorus atoms in the mono- or dialkyl orthophosphate structure. In other embodiments, the alkyl phosphate amine salt can contain at least about 50 mol% to about 80 mol% or 55 mol% to 65 mol% of phosphorus atoms in the alkyl pyrophosphate structure.

[0107] In other embodiments, the hydrocarbylamine can be a hindered amine represented by formula (III) R3—NR5—R4, where R3, R4, and R5 are independently C1-C30 hydrocarbyl groups. In other embodiments, R3, R4, and R5 can independently be C1-C6, C4-C18, or C6-C14 hydrocarbyl groups. In another embodiment, the hindered hydrocarbylamine can have at least one aromatic group. In other embodiments, the hydrocarbylamine can be an aromatic amine having an alkyl group directly attached to the nitrogen atom that salts with the phosphate ester, and wherein the nitrogen atom can optionally be further alkylated. In still other embodiments, the hydrocarbylamine can be a tertiary alkylamine bearing at least two branched alkyl groups. The at least two branched alkyl groups can be independently branched at the α or β position. In still other embodiments, the at least two branched alkyl groups can both be branched at the β position. In some embodiments, one or more of the alkyl groups of the alkyl phosphate structure can include 4-methylpent-2-yl groups.

[0108] In one embodiment, the resist can be a thiadiazole, such as 1,3,4-thiadiazole. In an embodiment, 1,3,4-thiadiazole can include substituents at the 2- and 5-positions of the thiadiazole ring, such as, for example, an alkyldithio moiety. Such resists can include those of the following formula

[0109]

[0110] wherein R1 and R2 are independently alkyl groups having from 1 to 12 carbons.

[0111] In one embodiment, the resist includes (i) 2,5-bis(alkyldithio)-1,3,4-thiadiazole, (ii) a benzotriazole having a hydrocarbyl substitution at at least one of the following ring positions 4-, or 5-, or 6- or 7-, or (iii) a benzotriazole having a hydrocarbyl substitution at at least one of the following ring positions 1- or 2- (wherein the benzotriazole is typically further reacted with an aldehyde and an amine).

[0112] In one embodiment, the resist includes 2,5-bis(alkyldithio)-1,3,4-thiadiazole. In various embodiments, the alkyl groups of 2,5-bis(alkyldithio)-1,3,4-thiadiazole contain from 1 to about 30, or about 2 to about 25, or 4 to about 20, or about 6 to about 16 carbon atoms. Examples of suitable 2,5-bis(alkyldithio)-1,3,4-thiadiazole include 2,5-bis(trioctyldithio)-1,3,4-thiadiazole, 2,5-bis(trinonyldithio)-1,3,4-thiadiazole, 2,5-bis(tridecyldithio)-1,3,4-thiadiazole, 2,5-bis(tridodecyldithio)-1,3,4-thiadiazole, 2,5-bis(tridodecyldithio)-1,3,4-thiadiazole, or mixtures thereof.

[0113] The corrosion inhibitor can be used alone or in combination with two, three, or more corrosion inhibitors. In one embodiment, the corrosion inhibitor comprises a mixture of the following: (i) 2,5-bis(alkyldithio)-1,3,4-thiadiazole, (ii) benzotriazole having a hydrocarbyl substitution at at least one of the following ring positions 4-, or 5-, or 6- or 7-, and (iii) benzotriazole having a hydrocarbyl substitution at at least one of the following ring positions 1- or 2- (usually the benzotriazole is further reacted with an aldehyde and an amine).

[0114] In different embodiments, the corrosion inhibitor is thiadiazole. The thiadiazole corrosion inhibitor can be present alone or in the form of a mixture with other thiadiazole corrosion inhibitors or other azole corrosion inhibitors, and the range includes from about 0.01 wt% to about 1 wt%, or from about 0.05 wt% to about 0.9 wt%, or from about 0.1 wt% to about 0.8 wt% or from about 0.2 wt% to about 0.7 wt% of the lubricant additive composition, or from 0.2 wt% to about 0.5 wt% or from 0.25 wt% to about 0.35 wt% of the lubricant additive composition.

[0115] The lubricant may also contain other additives, for example, such as, for instance, dispersants, antioxidants, viscosity modifiers, detergents, and other antiwear agents (in addition to the aforementioned amine (thio)phosphates). Those of ordinary skill in the art will understand that other additives can be used in the lubricant.

[0116] The dispersant may include, for example, "succinimide dispersant", which is a carboxyl dispersant prepared by reacting a hydrocarbyl-substituted succinic anhydride or its reactive equivalent with an amine such as poly(ethyleneamine); "amine dispersant", which is a reaction product of a relatively high molecular weight aliphatic or cycloaliphatic halide and an amine (such as polyalkylene polyamine); "Mannich dispersant", that is, a reaction product of an alkylphenol in which the alkyl group contains at least 30 carbon atoms with an aldehyde (especially formaldehyde) and an amine (especially polyalkylene polyamine); and "ester dispersant", which is similar to the aforementioned succinimide dispersant, except that they can be regarded as being prepared by the reaction of a hydrocarbyl acylating agent and an aliphatic polyol (such as glycerol, pentaerythritol, or sorbitol), as described in U.S. Patent 3,381,022.

[0117] Another class of ashless dispersants are high molecular weight esters. These materials are similar to the above-described succinimides, except that they can be considered to be prepared by the reaction of a hydrocarbyl acylating agent and an aliphatic polyol such as glycerol, pentaerythritol or sorbitol. Such materials are described in more detail in U.S. Patent No. 3,381,022. Aromatic succinate esters can also be prepared as described in U.S. Patent Publication 2010 / 0286414. In some cases, these ester-type dispersants can be post-treated with an amine such as poly(ethyleneamine).

[0118] Post-treated dispersants can also be used. Post-treated dispersants are generally obtained by reacting a carboxylic acid (e.g., succinimide), an amine or a Mannich dispersant with a reagent such as urea, thiourea, carbon disulfide, aldehyde, ketone, carboxylic acid, hydrocarbyl-substituted succinic anhydride, nitrile, epoxide, boron compound such as boric acid (to produce a "borated dispersant" as described above), phosphorus compound such as phosphoric acid or acid anhydride, 2,5-dimercapto-1,3,4-thiadiazole (DMTD) or an aromatic diacid having an acid group in the 1,3 or 1,4 position on the benzene ring such as terephthalic acid.

[0119] Borated dispersants are generally obtained by reacting a carboxylic acid (e.g., succinimide), an amine or a Mannich dispersant with a boron compound reagent such as boric acid (to produce a "borated dispersant"). Dispersants and their production methods are well known in the art. Borated dispersants can be additionally partially functionalized with sulfur or phosphorus. The dispersant component in the borated dispersant can be a mixture of multiple dispersants, and the multiple dispersants can be of different types; optionally, at least one can be a succinimide dispersant. In one embodiment, the borated dispersant can be a borated polyisobutylene succinimide dispersant, wherein its polyisobutylene moiety can have a number average molecular weight of 750 to 2200, or 750 to 1350 or 750 to 1150. One or more borated dispersants can be prepared in such a way that they have an N:CO ratio of 0.9:1 to 1.6:1, or 0.95:1 to 1.5:1, or 1:1 to 1.4:1. The amount of the borated dispersant in the composition can be, for example, 0.05 wt% to 2.0 wt%. In other embodiments, the amount is 0.1% to 1.0%, or 0.15% to 0.75% of the final blend fluid formulation. In the concentrate, this amount will proportionally be higher.

[0120] Mixtures of dispersants can also be used. The nitrogen content of the dispersant can be greater than or equal to about 11,000 ppm, or greater than or equal to about 11,500 ppm, or greater than or equal to about 12,000 ppm by weight of the dispersant.

[0121] The total amount of one or more dispersants (whether post-treated (e.g., boricated or non-boricated, but preferably boricated) or a combination thereof) in the composition can be, for example, from 0.01 wt% to 3 wt% of the final blended fluid formulation, or for example from 0.025 wt% to 2.75 wt% or from 0.05 wt% to 2.5 wt%, although on a concentrate basis, the amounts will be proportionally higher. In terms of the degree to which the dispersant is boricated, the dispersant can provide less than 250 ppm of boron, or less than 200 ppm of boron, or even less than 150 ppm of boron, or less than 100 ppm of boron, or less than 90 ppm of boron or even less than 80 ppm of boron to the composition, and in some cases less than 70 ppm of boron to the composition.

[0122] In certain embodiments, the dispersant can be prepared by a process involving the presence of small amounts of chlorine or other halogens, as described in U.S. Patent No. 7,615,521 (see, for example, column 4, lines 18 to 60 and Preparation Example A). Such dispersants generally have some carbocyclic structure in the linkage of the hydrocarbyl substituent to the acidic or amide "head" group. In other embodiments, the dispersant can be prepared by a thermal process involving an "ene" reaction without the use of any chlorine or other halogens, as described in U.S. Patent No. 7,615,521; dispersants prepared in this manner are generally derived from highly vinylidene (i.e., greater than 50% terminal vinylidene) polyisobutene (see column 4, lines 61 to column 5, line 30 and Preparation Example B). Such dispersants generally do not contain the above-described carbocyclic structure at the point of attachment. In certain embodiments, the dispersant can be prepared by free radical catalyzed polymerization of highly vinylidene polyisobutene with an ethylenically unsaturated acylating agent, as described in U.S. Patent No. 8,067,347.

[0123] The dispersant can also be a graft copolymer, which is the condensation reaction product of an olefin polymer having carboxylic acid (or equivalent) functional groups grafted thereon, and the grafted olefin is reacted with a monoamine or polyamine that can have a single primary amino group. If the olefin polymer is an ethylene / propylene copolymer, then the polyamine is not poly(vinylamine).

[0124] The polymer substrate will be an olefin polymer, such as those described above. The olefin polymer substrate employed in the derived graft copolymer will contain grafted carboxylic acid functional groups or reactive equivalents of carboxylic acid functional groups (e.g., acid anhydrides or esters). The reactive carboxylic acid functional groups will generally be present in the form of side groups attached, for example, by a grafting process.

[0125] Ethylenically unsaturated carboxylic acid substances are usually group-grafted onto the polymer backbone. These substances attached to the polymer usually contain at least one ethylenic bond (before the reaction) and at least one, such as two carboxylic acid (or its anhydride) groups or polar groups that can be converted into the carboxyl group by oxidation or hydrolysis. Maleic anhydride or its derivatives are suitable. It is grafted onto an olefin polymer (such as an ethylene copolymer or terpolymer) to obtain two carboxylic acid functional groups. Examples of additional unsaturated carboxylic acid substances include maleic anhydride, itaconic anhydride, or the corresponding dicarboxylic acids, such as maleic acid, fumaric acid, and their esters, as well as cinnamic acid and its esters.

[0126] Ethylenically unsaturated carboxylic acid substances can be group-grafted onto a polymer (such as an ethylene / propylene copolymer). The free-radical induced grafting of ethylenically unsaturated carboxylic acid substances can also be carried out in a solvent (such as hexane or mineral oil). It can be carried out at a high temperature in the range of 100 °C to 250 °C, such as 120 °C to 190 °C, or 150 °C to 180 °C, for example, above 160 °C.

[0127] Free-radical initiators that can be used include peroxides, hydroperoxides, and azo compounds, usually those free-radical initiators having a boiling point greater than about 100 °C and thermally decomposing within the grafting temperature range to provide free radicals. Representatives of these free-radical initiators include azobisisobutyronitrile and 2,5-dimethyl-hex-3-yne-2,5-bis-tert-butyl peroxide. The amount of the initiator can be 0.005 wt% to 1 wt% based on the weight of the reaction mixture solution. The grafting can be carried out under an inert atmosphere, such as under a nitrogen blanket. The resulting polymer intermediate is characterized by having carboxylic acid acylation functional groups within its structure.

[0128] In an alternative embodiment, an unsaturated carboxylic acid substance (such as maleic anhydride) is capable of first condensing with a monoamine or polyamine that usually has a single primary amino group (as described below), and the condensation product itself is then grafted onto the polymer backbone in a manner similar to that described above.

[0129] The amount of reactive carboxylic acid on the polymer chain, and in particular the amount of grafted carboxylic acid on the chain, is typically 0.5 wt% to 8 wt%, or 1 wt% to 7 wt%, or 1.5 wt% to 6 wt%, or in some embodiments 2 wt% to 5 wt%, based on the weight of the polymer backbone. In some embodiments, the amount of reactive carboxylic acid on the polymer chain, and in particular the amount of grafted carboxylic acid on the chain, can be from about 1 wt% to about 2 wt%, or in other embodiments from about 2 wt% to 3 wt%, or from about 3 wt% to 4 wt% or 4 wt% to 5 wt%. These numbers represent the amount of carboxylic acid-containing species, particularly referring to maleic anhydride as the grafting substance. As will be apparent to those skilled in the art, the amount can be adjusted to account for carboxylic acid-containing species having higher or lower molecular weights or higher or lower amounts of acid functional groups per molecule. The grafting can be to an extent to provide an acid-functionalized polymer having a total acid number (TAN, according to ASTM D664) of 5 mg KOH / g to 100 mg KOH / g, 10 mg KOH / g to 80 mg KOH / g, or 15 mg KOH / g to 75 mg KOH / g, or 20 mg KOH / g to 70 mg KOH / g, or from about 20 mg KOH / g to about 60 mg KOH / g or 65 mg KOH / g.

[0130] The acid-containing polymer is reacted with a monoamine or polyamine that typically has a single primary amino group. If the olefin polymer is an ethylene / propylene copolymer, then the polyamine is not poly(vinylamine). The reaction can consist of a condensation to form an imide, amide, or semi-amide or amide ester (assuming a portion of the alcohol also reacts) or amine salt. The primary amino group will typically condense to form an amide or, in the case of maleic anhydride, an imide. It should be noted that in certain embodiments, the amine will have a single primary amino group, that is, it will not have two or more primary amino groups (except for a negligible amount of additional primary amino groups within the overall amine component, such as less than 5% or 2% or 1% or 0.5%, or 0.01% to 0.1%, particularly 1% or less, such as 0.01% to 1% of the amine groups being primary amino groups). This feature will minimize the amount of crosslinking that might otherwise occur. Poly(vinylamine) can generally and in a simplistic way be described as H2N-(C2H4-NH-)n-C2H4-NH2, where n can be, for example, 2 to 6. These generally have an average of about 2 primary amino groups and thus are generally not desired for the functionalization of ethylene / propylene copolymers so that any undesired crosslinking can be minimized or avoided. In those embodiments where the polyamine is not poly(vinylamine), the amine component used to prepare the condensation product will contain no or substantially no poly(vinylamine), such as less than 5 wt% of the amine component, or less than 1 wt%, or 0.01 wt% to 0.1 wt% is poly(vinylamine).

[0131] Suitable primary amines can include aromatic amines, such as amines in which a carbon atom of the aromatic ring structure is directly attached to the amino nitrogen. The amine can be a monoamine or a polyamine. The aromatic ring will typically be a mononuclear aromatic ring (i.e., a ring derived from benzene), but can include fused aromatic rings, such as those derived from naphthalene. Examples of aromatic amines include aniline, N-alkyl anilines (such as N-methyl aniline) and N-butyl aniline, bis(p-methylphenyl)amine, naphthylamine, 4-aminodiphenylamine, N,N-dimethylbenzidine, 4-(4-nitrophenylazo)aniline (Disperse Orange 3), sulfamethazine, 4-phenoxyaniline, 3-nitroaniline, 4-aminoacetanilide, phenyl 4-amino-2-hydroxy-benzoate (phenyl aminosalicylate), N-(4-amino-5-methoxy-2-methyl-phenyl)-benzamide (Fast Violet B), N-(4-amino-2,5-dimethoxy-phenyl)-benzamide (Fast Blue RR), N-(4-amino-2,5-diethoxy-phenyl)-benzamide (Fast Blue BB), N-(4-amino-phenyl)-benzamide and 4-phenylazoaniline. Other examples include p-ethoxyaniline, p-dodecylaniline, cyclohexyl-substituted naphthylamine and thiophenyl-substituted aniline. Examples of other suitable aromatic amines include amino-substituted aromatic compounds and amines in which the amine nitrogen is part of the aromatic ring, such as 3-aminoquinoline, 5-aminoquinoline and 8-aminoquinoline. Also included are aromatic amines such as 2-aminobenzimidazole, which contains a secondary amino group directly attached to the aromatic ring and a primary amino group attached to the imidazole ring. Other amines include N-(4-anilinophenyl)-3-aminobutanamide (i.e., φ-NH-φ-NH-COCH2CH(CH3)NH2). Additional aromatic amines include aminocarbazole, aminoindole, aminopyrrole, aminoindazolone, aminopyridine, mercaptotriazole, aminophenothiazine, aminopyridine, aminopyrazine, aminopyrimidine, pyridine, pyrazine, pyrimidine, aminothiadiazole, aminothiotiadiazole and aminobenzotriazole. Other suitable amines include 3-amino-N-(4-anilinophenyl)-N-isopropylbutanamide and N-(4-anilinophenyl-3-{(3-aminopropyl)-(cocoalkyl)amino}butanamide. Other aromatic amines that can be used include various aromatic amine dye intermediates containing multiple aromatic rings connected, for example, by an amide structure. Examples include substances of the general formula structure -CONH-φ-NH2, where the phenyl group can be substituted. Suitable aromatic amines include those in which the amine nitrogen is a substituent on an aromatic carboxylic acid compound (i.e., the nitrogen is not sp2 hybridized within the aromatic ring).

[0132] The amine can also be non-aromatic, or in other words, an amine in which the amino nitrogen is not directly attached to a carbon atom of an aromatic ring, or an amine in which the amine nitrogen is not part of an aromatic ring, or an amine in which the amine nitrogen is not a substituent on an aromatic carboxylic acid compound. In some cases, such non-aromatic amines can be considered aliphatic or cycloaliphatic. Such amines can be straight-chain, branched-chain or functionalized with certain functional groups. Non-aromatic amines can include monoamines having, for example, 1 to 8 carbon atoms, such as methylamine, ethylamine and propylamine, as well as various higher amines. Diamines or polyamines can also be used and will generally have only a single primary amino group. Examples include dimethylaminopropylamine, diethylaminopropylamine, dibutylaminopropylamine, dimethylaminoethylamine, diethylaminoethylamine, dibutylaminoethylamine, 1-(2-amino-ethyl)piperidine, 1-(2-aminoethyl)-pyrrolidone, N,N-dimethylethylamine; 3-(dimethylamino)-1-propylamine; O-(2-aminopropyl)-O'-(2-methoxyethyl)polypropylene glycol; N,N-dimethyldipropylenetriamine, aminoethylmorpholine, 3-morpholinopropylamine; aminoethyl ethylene urea and aminopropylmorpholine.

[0133] In certain embodiments, the non-aromatic amines can be used alone or in combination with each other or in combination with aromatic amines. In some embodiments, the amount of the aromatic amine can be trace compared to the amount of the non-aromatic amine, or in certain cases, the composition can be substantially free or free of aromatic amines.

[0134] In certain embodiments, calculated using ASTM D5291, the grafted olefin polymer can have a nitrogen content of 0.05 wt% to 3 wt%, or 0.1 wt% to 2.5 wt%, or 0.15 wt% to 2 wt%, or 0.2 wt% to 1.75 wt%, or 0.25 wt% to 1.6 wt%.

[0135] The lubricant additive composition can also include antioxidants, for example, aromatic amine antioxidants, hindered phenol antioxidants (including ester-containing hindered phenol antioxidants) and sulfurized olefin antioxidants. These antioxidants can be present in an amount of 0.01 wt% to 5 wt%, or 0.15 wt% to 3 wt%, or 0.2 wt% to 1.5 wt%, or 0.2 wt% to 1 wt% or 0.25 wt% to 0.7 wt%.

[0136] In one embodiment, the lubricant additive composition of the present invention includes an arylamine antioxidant. The arylamine antioxidant can be phenyl-α-naphthylamine (PANA), or a hydrocarbyl-substituted diphenylamine or a mixture thereof. The hydrocarbyl-substituted diphenylamine can include mono- or di-C4 to C16-, or C6 to C12-, or C9-alkyldiphenylamine. For example, the hydrocarbyl-substituted diphenylamine can be octyldiphenylamine or dioctyldiphenylamine, dinonyldiphenylamine, typically dinonyldiphenylamine.

[0137] When present, the arylamine antioxidant may be present in the lubricant additive composition in an amount of 0.2 wt% to 1.2 wt%, or 0.3 wt% to 1.0 wt%, or 0.4 wt% to 0.9 wt% or 0.5 wt% to 0.8 wt%.

[0138] The hindered phenol antioxidant often contains secondary butyl and / or tertiary butyl groups as sterically hindering groups. The phenol group is usually further substituted by a hydrocarbon group and / or a bridging group linked 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, Irganox TM L-135 or butyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

[0139] If present, the hindered phenol antioxidant may be present in the lubricant additive composition in an amount of 0.1 wt% to 1 wt%, or 0.2 wt% to 0.9 wt%, or 0.1 wt% to 0.4 wt% or 0.4 wt% to 1.0 wt%.

[0140] The antioxidant also includes sulfurized olefins, such as monosulfides or disulfides or mixtures thereof. These materials typically have sulfur linkages containing 1 to 10 sulfur atoms, such as 1 to 4 or 1 or 2 sulfur atoms. Substances that can be sulfurized for use as sulfurized antioxidants in the lubricant additive composition may include oils, fatty acids and esters, olefins and polyolefins prepared therefrom, terpenes or Diels-Alder adducts. Details of methods for preparing certain such sulfurized substances can be found in U.S. Patents 3,471,404 and 4,191,659.

[0141] Sulfurized olefins are well-known commercial materials and are substantially nitrogen-free, i.e., those sulfurized olefins without nitrogen functional groups are readily available. The properties of olefin compounds that can be sulfurized are diverse. They contain at least one olefin double bond, which is defined as a non-aromatic double bond; that is, a double bond connecting two aliphatic carbon atoms. In its broadest sense, an olefin can be defined by the formula R*1R*2C=CR*3R*4, where each of R*1, R*2, R*3, and R*4 is hydrogen or an organic group. Generally speaking, the R groups that are not hydrogen in the above formula can be satisfied by groups such as —C(R*5)3, —COOR*5, —COOM, —X, —YR*5, or —Ar, where each R 5 is independently hydrogen, alkyl, alkenyl, aryl, substituted alkyl, substituted alkenyl, or substituted aryl, provided that any two R 5 groups can be alkylene or substituted alkylene, thereby forming a ring of up to 12 carbon atoms; M is one equivalent of a metal cation (preferably of class I or II, e.g., sodium, potassium, barium, calcium); X is a halogen (e.g., chloro, bromo, or iodo); Y is oxygen or divalent sulfur; Ar is an aryl or substituted aryl group of up to 12 carbon atoms. Any two of R*1, R*2, R*3, and R*4 can also together form an alkylene or substituted alkylene group; that is, the olefinic compound can be cycloaliphatic.

[0142] One type of sulfurized olefin is prepared according to the detailed teachings of U.S. Patent No. 4,957,651. A co-sulfurized mixture of two or more reactants selected from the group consisting of: (1) at least one fatty acid ester of a polyol, (2) at least one fatty acid, (3) at least one olefin, and (4) at least one fatty acid ester of a monohydric alcohol is described therein. Reactant (3) (the olefin component) contains at least one olefin. The olefin is preferably an aliphatic olefin, which will generally contain from 4 to 40 carbon atoms, preferably from 8 to 36 or from 12 to 18 carbon atoms. Terminal olefins or α-olefins are preferred, especially those having from 12 to 20 carbon atoms. Mixtures of these olefins are commercially available, and such mixtures are contemplated for use in the present invention.

[0143] Sulfurized olefins can be prepared by reacting a single reactant or a mixture of suitable reactants with a sulfur source. The sulfurization reaction is usually carried out at an elevated temperature (e.g., 50 °C to 350 °C or 100 °C to 200 °C), with effective stirring and usually in an inert atmosphere such as nitrogen, optionally in the presence of an inert solvent. Sulfurizing agents that can be used in the process of the present invention include elemental sulfur (which is preferred), hydrogen sulfide, sulfur halides, sodium sulfide, and mixtures of hydrogen sulfide with sulfur or sulfur dioxide. Generally, the amount of sulfur or sulfurizing agent employed is calculated based on the total olefinic unsaturated groups of the mixture. Usually, 0.5 mole to 3 moles of sulfur are employed per mole of olefinic bond.

[0144] An olefinic compound is generally an olefinic compound in which each of the above R groups that is not hydrogen is independently an alkyl, alkenyl, or aryl group. Mono-olefinic and di-olefinic compounds (especially the former) are preferred, and especially terminal mono-olefinic hydrocarbons; that is, those in which R3 and R4 are hydrogen and R1 and R2 are alkyl or aryl groups, especially alkyl groups having 1 to 30, or 1 to 16, or 1 to 8 or 1 to 4 carbon atoms (i.e., the olefins are aliphatic). Olefinic compounds having 3 to 30 or 3 to 16 (usually less than 9) carbon atoms can be used.

[0145] Isobutene, propylene, and their dimers, trimers, and tetramers, and mixtures thereof can be used as olefinic compounds for vulcanization, can be used as terpene compounds (i.e., various isomeric terpenic olefins having the empirical formula C10H16), and various synthetic and naturally occurring oxygenated derivatives thereof.

[0146] In one embodiment, the vulcanized organic composition is a sulfur-containing material that includes the reaction product of a sulfur source and at least one Diels-Alder adduct in a molar ratio of at least 0.75:1. Generally, the molar ratio of the sulfur source to the Diels-Alder adduct is 0.75 to 4.0, or 1 to 2.0, or 1 to 1.8. The Diels-Alder adduct can be prepared from a dienophile having at least one carboxylic acid ester group represented by —C(O)O—Ro, where Ro is the residue of a saturated fatty alcohol having up to 40 carbon atoms, and the fatty alcohol from which —Ro is derived is a mono- or polyhydric alcohol, such as an alkylene glycol, an alkanol, an aminoalkanol, an alkoxy-substituted alkanol, ethanol, ethoxyethanol, propanol, butanol, β-diethylamino-ethanol, dodecanol, diethylene glycol, tripropylene glycol, tetrabutylene glycol, hexanol, octanol, and isooctanol. Generally, there will be no more than two —C(O)—O—Ro groups, and preferably only one —C(O)—O—Ro group. Such materials can also be described as cyclohexene compounds bearing ester substituents. A preferred vulcanized olefin is vulcanized 4-butoxycyclohexene. This and other vulcanized olefins can be further treated with other materials such as aryl phosphates (e.g., triphenyl phosphite).

[0147] Other vulcanized olefins include vulcanized vegetable oils and vulcanized lard (i.e., vulcanized oils that are usually of animal origin).

[0148] The amount of the sulfurized olefin in the fully formulated lubricant will be an amount sufficient to improve the antiwear properties of the lubricant as measured by any well-known wear test, as described below. Such amounts will typically be from 0.05 wt% to 1.5 wt% or to 1 wt%, preferably from 0.10 wt% to 0.80 wt%, or from 0.15 wt% to 0.70 wt% or from 0.20 wt% to 0.60 wt%. In the concentrate, the amount will be approximately an order of magnitude greater, e.g., from 0.5 wt% to 15 wt% or to 10 wt%. A concentration of 0.5% sulfurized 4-carbon butoxy cyclohexene will typically impart to the lubricant about 5 - 80 weight ppm of sulfur, which is consistent with a low sulfur composition. (The compositions in this specification having less than 0.4% or 0.35% S, or less than 0.3% S or alternatively less than 0.27% S are determined based on the total sulfur from all sources (including sulfurized olefins and e.g. any sulfonates, sulfurized phenates and dithiophosphates). The lubricant composition may also contain, e.g., from 0.05 wt% or 0.1 wt% to 0.4 wt%, or to 0.35 wt%, or to 0.3 wt% or to 0.27 wt% total sulfur.)

[0149] The lubricant additive composition may also contain a viscosity modifier. One type of viscosity modifier that can be employed is a poly(meth)acrylate polymer viscosity modifier. As used herein, the following ranges of the viscosity modifier are measured by GPC using polystyrene standards having a weight average molecular weight in the range of 350 to 100,000.

[0150] In one embodiment, the lubricant additive composition can include a linear poly(meth)acrylate polymer having a weight average molecular weight of 5,000 to 25,000, or 8,000 to 20,000.

[0151] The linear poly(meth)acrylate polymer can be present in the lubricant additive composition in an amount of about 0.1 wt% to about 5 wt%, or 0.1 wt% to 4 wt%, or 0.2 wt% to 3 wt%, or 0.5 wt% to 3 wt%, or 1.0 wt% to 4 wt%, 0.6 wt% to 4 wt%, or 0.75 wt% to 3 wt% or 0.2 wt% to 0.75 wt%.

[0152] The poly(meth)acrylate polymer may be derived from a monomer composition comprising: (a) 50 wt% to 95 wt% or 60 wt% to 80 wt% of an alkyl (meth)acrylate, wherein the alkyl group of the (meth)acrylate has 10 to 15 carbon atoms; (b) 1 wt% to 40 wt% or 4 wt% to 35 wt% of an alkyl (meth)acrylate, wherein the alkyl group of the (meth)acrylate has 1 to 9 carbon atoms; (c) 1 wt% to 10 wt% or 1 wt% to 8 wt% of a monomer having a dispersant functionality; (d) 0 wt% to 4 wt%, 0 wt% to 2 wt% or 0 wt% of a vinyl aromatic monomer (usually styrene); and (e) 0 wt% to 9 wt% or 0 wt% to 6 wt% of an alkyl (meth)acrylate, wherein the alkyl group of the (meth)acrylate has 16 to 18 carbon atoms. In one embodiment, the linear polymer may contain 0 wt% to 20 wt% of a 16 to 18 alkyl (meth)acrylate.

[0153] In one embodiment, the linear polymer may comprise a poly(meth)acrylate (usually polymethacrylate) the units of which are derived from a mixture of alkyl (meth)acrylate monomers that (a) contain 8 to 24, or 10 to 18, or 12 to 15 carbon atoms in the alcohol-derived part of the ester group and (b) contain 6 to 11, or 8 to 11, or 8 carbon atoms in the alcohol-derived part of the ester group and which has a 2-(C1-4 alkyl) substituent, and optionally at least one monomer selected from the group consisting of: a (meth)acrylate that contains 1 to 7 carbon atoms in the alcohol-derived part of the ester group and which is different from (meth)acrylates (a) and (b), a vinyl aromatic compound (or vinyl aromatic monomer); and a nitrogen-containing vinyl monomer; provided that no more than 60 wt%, or no more than 50 wt%, or no more than 35 wt% of the esters contain no more than 10 carbon atoms in the alcohol-derived part of the ester group. US 6,124,249 or EP 0 937 769A1 paragraphs

[0019] and

[0031] to

[0067] describe this type of linear polymer in more detail. (When written as R'C(=O)-OR, the "alcohol-derived part" refers to the "-OR" part of the ester, whether it is actually prepared by reaction with an alcohol or not). Optionally, the linear polymer may additionally contain a third monomer. The third monomer may be styrene or a mixture thereof. The third monomer may be present in an amount of 0% to 25%, or 1% to 15%, 2% to 10%, or even 1% to 3% of the polymer composition.

[0154] Typically, the molar ratio of ester (a) to ester (b) in the copolymer ranges from 95:5 to 35:65, or from 90:10 to 60:40, or from 80:20 to 50:50.

[0155] The esters are typically aliphatic esters, typically alkyl esters. In one embodiment, the ester of (a) can be a C12-15 alkyl (meth)acrylate, and the ester of (b) can be 2-ethylhexyl (meth)acrylate.

[0156] In one embodiment, the ester group in ester (a) contains a branched alkyl group. The ester group can contain 2% to 65%, or 5% to 60% of ester groups having a branched alkyl group. The branched alkyl group can be β-branched and can contain 8 to 60, or 8 to 30 or 8 to 16 carbon atoms. For example, the branched alkyl group can be derived from 2-ethylhexanol, 2-butyl octanol, 2-hexyl decanol, 2-octyl dodecanol, 2-decyl tetradecanol, or mixtures thereof, or commercially available alcohols such as those available from Sasol branched Guerbet alcohols.

[0157] The C1-4 alkyl substituents can be methyl, ethyl, and any isomers of propyl and butyl.

[0158] The weight-average molecular weight of the linear poly(meth)acrylate can be 45,000 or lower, or 35,000 or lower, or 25,000 or lower, or from 8000 to 25,000, or from 10,000 to 35,000, or from 12,000 to 20,000.

[0159] The linear polymer can be referred to as a viscosity modifier, or a dispersant viscosity modifier, because it can exhibit dispersant functionality. The "dispersant viscosity modifier" mentioned herein does not include dispersants, which are a separate class of compounds. The linear polymer can be used as a standalone viscosity modifier (or dispersant viscosity modifier), which is present as a linear (meth)acrylic polymer viscosity modifier having dispersant functionality at 0.5 wt% to 4 wt%, wherein the weight-average molecular weight of the linear polymer is from 5,000 to 25,000, or from 10,000 to 20,000, and wherein the kinematic viscosity of the oil having lubricating viscosity at 100 °C is from 4 cSt to 6 cSt (mm2 / s), and the viscosity index is from 120 to 150.

[0160] In one embodiment, the lubricant additive composition can contain only two linear polymer viscosity modifiers having dispersant functionality, wherein the weight-average molecular weight of the linear polymer is from 5,000 to 25,000 or from 10,000 to 20,000.

[0161] In one embodiment, the lubricant additive composition can comprise from 0.1 wt% to 4 wt% (or from 0.2 wt% to 3 wt%) of a linear (meth)acrylic polymer viscosity modifier having dispersant functionality, wherein the linear polymer has a weight average molecular weight of greater than 25,000 to 400,000 (or to 350,000) or 30,000 to 150,000. A linear (meth)acrylic polymer having a weight average molecular weight of greater than 25,000 to 400,000 (or to 350,000) can be considered chemically similar to a linear (meth)acrylic polymer having a weight average molecular weight of 5,000 to 25,000, except for the difference in weight average molecular weight.

[0162] The lubricant additive composition can include a linear polymer viscosity modifier having dispersant functionality, comprising: from 0.1 wt% to 5 wt% (or from 1 wt% to 4 wt%) of a linear (meth)acrylic polymer viscosity modifier having dispersant functionality, wherein the linear polymer has a weight average molecular weight of 10,000 to 20,000; and from 0.1 wt% to 4 wt% (or from 1 wt% to 3 wt%) of a linear (meth)acrylic polymer viscosity modifier having dispersant functionality, wherein the linear polymer has a weight average molecular weight of greater than 20,000 to 250,000 (or 30,000 to 150,000).

[0163] As described below, the molecular weight of the viscosity modifier has been determined using known methods, such as GPC analysis using polystyrene standards. Methods for determining the molecular weight of polymers are well known. For example, these methods are described in: (i) P.J. Flory, “Principles of star polymer Chemistry”, Cornell University Press 91953), Chapter VII, pages 266 to 315; or (ii) “Macromolecules, an Introduction to star polymer Science”, edited by F.A. Bovey and F.H. Winslow, Academic Press (1979), pages 296 to 312.

[0164] Another type of viscosity modifier that can be used is an ethylene α-olefin copolymer. The ethylene α-olefin copolymer includes those having a backbone with 1 to 3 different α-olefin monomers (in addition to the ethylene monomer), 1 to 3 different α-olefin monomers in one embodiment, and 1 α-olefin monomer in addition to the ethylene monomer in yet another embodiment. The α-olefin monomers include 3 to 20, and in other embodiments 3 to 12, or 3 to 10, or 3 to 6 or 3 to 4 carbon atoms, and in another embodiment 3 carbon atoms (i.e., propylene). The olefin can be an α-olefin having the number of carbon atoms listed above.

[0165] The ethylene α-olefin copolymer will have greater than 5 wt% ethylene monomer units, and in some embodiments at least 10 wt% and up to 90 wt%, or 15 wt% to 85 wt%, or 20 wt% to 80 wt% or 30 wt% to 50 wt% ethylene monomer units. In certain embodiments, the amount of ethylene monomer will be 30 wt% to 50 wt%; in other embodiments, the amount of ethylene monomer will be 75 wt% to 85 wt% or 79 wt% to 81 wt%. In other words, the amount of ethylene monomer can be 15 mol% to 90 mol%, or 25 mol% to 85 mol%, or 40 mol% to 60 mol% or 45 mol% to 55 mol%.

[0166] Thus, the ethylene olefin copolymer contains ethylene monomer and at least one other comonomer derived from an α-olefin having the formula H2C=CHR3, where R3 is a hydrocarbyl group, an alkyl radical containing 1 to 18, 1 to 12, 1 to 10, 1 to 6 or 1 to 3 carbon atoms in one embodiment. The hydrocarbyl group includes alkyl radicals having straight-chain, branched-chain or mixtures thereof.

[0167] Examples of suitable comonomers include propylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene, 1-decene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene or mixtures thereof. The comonomer can be 1-butene, propylene or mixtures thereof. Examples of α-olefin copolymers include ethylene-propylene copolymers and ethylene-1-butene copolymers and mixtures thereof.

[0168] Polymer (c) may have a kinematic viscosity at 100 °C of at least 35 mm2 / s, or at least 50 mm2 / s, or at least 100 mm2 / s or at least 500 mm2 / s. In certain embodiments, polymer (c) may have a kinematic viscosity at 100 °C of at least about 500 mm2 / s, or at least about 1000 mm2 / s, or 1500 mm2 / s or 2000 mm2 / s, a feature that differentiates it from much lower viscosity analogs that can be used as base oils. The number average molecular weight of the polymer can be from 1000 to 8000, or from 1000 to 5000, or from 1300 to 8000, or from 1500 to 3000, or from 1800 to 2500, or about 2000, or from 2500 to 5000, or from 3500 to 4500 or about 4000. Its polydispersity (Mw / Mn) can be in the range of 1.3 to 4, or 1.4 to 3 or 1.4 to 2. It can be prepared by known methods by polymerizing (usually) ethylene and an α-olefin such as propylene using an AlCl3 or BF3 catalyst or by other known methods.

[0169] Another type of viscosity modifier is a graft copolymer as described above for dispersant graft copolymers.

[0170] In one embodiment, the lubricant for the method may further contain a metal-containing detergent. The metal-containing detergent can be an overbased detergent. An overbased detergent, also referred to as an overbased or superbasic salt, is characterized by a metal content that exceeds the stoichiometric amount required for neutralization and a particular acidic organic compound that reacts with the metal. The overbased detergent can be selected from the group consisting of sulfur-free phenates, sulfur-containing phenates, sulfonates, salicylates, and mixtures thereof.

[0171] The metal-containing detergent can also include a "mixed" detergent formed with a mixed surfactant system that includes a phenate and / or sulfonate component, e.g., phenate / salicylate, sulfonate / phenate, sulfonate / salicylate, sulfonate / phenate / salicylate, as described in, for example, U.S. Pat. Nos. 6,429,178; 6,429,179; 6,153,565; and 6,281,179. In the case of using a hybrid sulfonate / phenate detergent, for example, the mixed detergent will be considered equivalent to the amounts of different phenate and sulfonate detergents that would be separately introduced with similar amounts of phenate and sulfonate soaps.

[0172] Overbased metal-containing detergents can be sodium, calcium, or magnesium phenolates, or mixtures thereof, sulfur-containing phenolates, sulfonates, salicyl alcoholates, and salicylates. Overbased phenates and salicylates typically have a total base number (TBN) of 180 to 450. High-based sulfonates typically have a TBN of 250 to 600, or 300 to 500. High-based detergents are known in the art. In one embodiment, the sulfonate detergent can be a linear alkylbenzene sulfonate detergent with a metal ratio of at least 8, as described in paragraphs

[0026] to

[0037] of U.S. Patent Publication 2005065045 (and U.S. Patent No. 7,407,919). Linear alkylbenzene sulfonate detergents can be particularly useful for helping to improve fuel economy. The linear alkyl group can be attached to the benzene ring at any position along the straight chain of the alkyl group (but typically at the 2, 3, or 4 positions of the straight chain, and in some cases, primarily at the 2 position), resulting in a linear alkylbenzene sulfonate detergent. High-based detergents are known in the art. High-based detergents can be present in an amount of 0 wt% to 15 wt%, or 0.1 wt% to 10 wt%, or 0.2 wt% to 8 wt% or 0.2 wt% to 3 wt%. For example, in a heavy-duty diesel engine, the detergent can be present in the lubricating composition at 2 wt% to 3 wt%. For a passenger car engine, the detergent can be present in the lubricating composition at 0.2 wt% to 1 wt%.

[0173] The metal-containing detergent provides sulfated ash to the lubricating composition. The sulfated ash can be determined by ASTM D874. In one embodiment, the lubricating composition of the present invention comprises a metal-containing detergent in an amount that provides at least 0.4 wt% sulfated ash to the total composition. In another embodiment, the metal-containing detergent is present in an amount that provides at least 0.6 wt% sulfated ash, or at least 0.75 wt% sulfated ash, or even at least 0.9 wt% sulfated ash to the lubricating composition.

[0174] The lubricant can also contain other antiwear agents in addition to the amine (thio)phosphates described above.

[0175] For example, in one embodiment, the lubricant can contain a nonionic phosphorus compound as a hydrocarbyl phosphite. The hydrocarbyl-substituted phosphites of the present invention include those represented by the following formula:

[0176]

[0177] where each R''' is independently hydrogen or a hydrocarbyl group, provided that at least one of the R''' groups is a hydrocarbyl group.

[0178] In various embodiments, each hydrocarbyl group of R''' contains at least about 2 or at least about 4 carbon atoms. Generally, the combined total of carbon atoms present on the two R''' groups is less than about 45, or less than about 35 or less than about 25. Examples of suitable ranges for the number of carbon atoms present on the R''' groups include from about 2 to about 40, from about 3 to about 24, or from about 4 to about 20. Examples of suitable hydrocarbyl groups include propyl, butyl, tert-butyl, pentyl, hexyl, dodecyl, tetradecyl, hexadecyl, or octadecyl groups. Generally speaking, the hydrocarbyl phosphite is soluble or at least dispersible in oil. In one embodiment, the hydrocarbyl phosphite is dibutyl hydrogen phosphite or C16-18 alkyl hydrogen phosphite or dialkyl phosphite. A more detailed description of nonionic phosphorus compounds is included in columns 9, line 48 to column 11, line 8 of U.S. Patent No. 6,103,673.

[0179] In one embodiment, other antiwear agents can be amide dithiophosphates. A more detailed description of amide dithiophosphates can be found in U.S. Patent No. 4,938,884. The description of the molecular structure is in columns 2, line 4 to line 28. Suitable examples of preparation are disclosed in Examples 1 to 7 (columns 8, line 45 to column 10, line 13 of U.S. Patent No. 4,938,884). Generally, amide dithiophosphates are prepared by adding dithiophosphoric acid to an acrylamide such as acrylamide, methacrylamide, methylene bisacrylamide, or methylene bismethacrylamide. In one embodiment, the amide dithiophosphate includes a methylene bisacrylamide or methylene bismethacrylamide product, which is prepared by: adding dithiophosphoric acid to acrylamide to form an adduct; and then reacting the adduct with formaldehyde to prepare a methylene-coupled product.

[0180] Other antiwear agents can be phosphorus-containing amides. Phosphorus-containing amides are prepared by the reaction of phosphoric acid, preferably dithiophosphoric acid, with an unsaturated amide. Examples of unsaturated amides include acrylamide, N,N'-methylene bisacrylamide, methacrylamide, crotonamide, etc. The reaction product of phosphoric acid and the unsaturated amide can be further reacted with a linking or coupling compound such as formaldehyde or paraformaldehyde. Phosphorus-containing amides are known in the art and are disclosed in U.S. Patent Nos. 4,670,169, 4,770,807, and 4,876,374, the disclosures of which regarding phosphorus-containing amides and their preparation are incorporated herein by reference.

[0181] In one embodiment, other antiwear agents can be dithiophosphates containing an ester functional group and can be prepared by the reaction of dithiophosphoric acid with an α,β-unsaturated carboxylic acid compound (such as acrylic acid or methacrylic acid or esters). In the case of using carboxylic acids, if desired, the ester can be formed by subsequent reactions known to those skilled in the art. The unsaturated carboxylic acid ester can contain 4 to 40, preferably 4 to 24, and still more preferably 4 to 12 carbon atoms. Preferably, the unsaturated carboxylic acid ester is an allyl or vinyl ester of a carboxylic acid or an ester of an unsaturated carboxylic acid.

[0182] The vinyl ester of a carboxylic acid can be represented by the formula R6CH=CH—O(O)CR7, where R6 is hydrogen or a hydrocarbon group having 1 to 30 carbon atoms, preferably 1 to 12 carbon atoms, and still more preferably hydrogen; and R7 is a hydrocarbon group having 1 to 30 carbon atoms, preferably 1 to 12 carbon atoms, and more preferably 1 to 8 carbon atoms. Examples of vinyl esters include vinyl acetate, vinyl 2-ethylhexanoate, vinyl butyrate, and vinyl crotonate.

[0183] In another embodiment, the unsaturated carboxylic acid ester is an ester of an unsaturated carboxylic acid (such as maleic acid, fumaric acid, acrylic acid, methacrylic acid, itaconic acid, citraconic acid, etc.). In one embodiment, the ester is represented by the formula R8O—(O)C—CH=CH—C(O)ORg, where each Rg is independently a hydrocarbon group having 1 to 18 carbon atoms, preferably 1 to 12 carbon atoms, and more preferably 1 to 8 carbon atoms.

[0184] Examples of unsaturated carboxylic acid esters that can be used in the present invention include methyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, ethyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate, ethyl maleate, butyl maleate, and 2-ethylhexyl maleate. The above list includes mono-esters and di-esters of maleic acid, fumaric acid, and citraconic acid.

[0185] Other antiwear agents can be, for example, dithiophosphates. The dithiophosphate can be formed by the reaction of dithiophosphoric acid represented by (RO)2PSSH with an unsaturated compound. In one embodiment, the unsaturated compound is an unsaturated carboxylic acid or ester. Examples of unsaturated carboxylic acids or acid anhydrides include acrylic acid or esters, methacrylic acid or esters, itaconic acid or esters, fumaric acid or esters, and maleic acid, acid anhydride or esters.

[0186] Other antiwear agents can also be sulfur-containing phosphites. The sulfur-containing phosphites can include, for example, substances represented by the formula [R1O(OR2)(S)PSC2H4(C)(O)OR4O]nP(OR5)2-n(O)H, where R1 and R2 are each independently a hydrocarbyl group having 3 to 12 carbon atoms or 6 to 8 carbon atoms, or where R1 and R2 together with the adjacent O atoms and P atom form a ring containing 2 to 6 carbon atoms; R4 is an alkylene group having 2 to 6 carbon atoms or 2 to 4 carbon atoms; R5 is hydrogen or a hydrocarbyl group having 1 to about 12 carbon atoms; and n is 1 or 2. The C12-22 hydrocarbyl esters of phosphorous acid can be present in the lubricant composition in an amount of about 0.05 wt% to about 1.5 wt% of the lubricant composition, or about 0.1 wt% to about 1.0 wt% of the lubricant composition.

[0187] Unless otherwise indicated, the amounts of each chemical component described do not include any solvents or diluent oils that may typically be present in commercial substances, i.e., on an active chemical basis. However, unless otherwise indicated, each chemical or composition mentioned herein should be interpreted as a commercial grade substance, which may contain isomers, by-products, derivatives, and other such substances that are commonly understood to be present in commercial grades.

[0188] As used herein, the term "hydrocarbyl" refers to a group having a carbon atom directly attached to the remainder of the molecule, where the group consists of at least carbon and hydrogen atoms. If the hydrocarbyl group contains more than one carbon atom, these carbons need not be connected to each other. For example, at least two carbons can be connected via a suitable element or group. In various embodiments, the term "hydrocarbyl" refers to a group having a carbon atom directly attached to the remainder of the molecule, where the group consists of carbon, hydrogen, and optionally one or more heteroatoms, provided that the heteroatoms do not alter the predominantly hydrocarbon nature of the substituent. The heteroatoms can connect at least two carbons in the hydrocarbyl group and optionally up to two non-hydrocarbon substituents. Suitable heteroatoms will be apparent to those skilled in the art and include, for example, sulfur, nitrogen, oxygen, phosphorus, and silicon. Optionally, when the hydrocarbyl group contains heteroatoms, there will be no more than two heteroatoms per ten carbon atoms in the hydrocarbyl group. Suitable non-hydrocarbon substituents will also be apparent to those skilled in the art and include, for example, halo groups, hydroxy groups, alkoxy groups, mercapto groups, alkyl mercapto groups, nitro groups, nitroso groups, and sulfinyl groups.

[0189] Thus, examples of hydrocarbyl groups in the context of the present technology include:

[0190] - hydrocarbyl groups selected from aliphatic (e.g., alkyl or alkenyl), cycloaliphatic (e.g., cycloalkyl, cycloalkenyl, cyclo-dienyl), and aromatic groups;

[0191] - A substituted hydrocarbon group selected from the hydrocarbon groups defined in (i) substituted with no more than two non-hydrocarbon substituents and / or one or more hydrocarbon substituents, the non-hydrocarbon substituents being selected from the group consisting of halo, hydroxy, alkoxy, mercapto, alkylmercapto, nitro, nitroso and sulfinyl;

[0192] - A hydrocarbon group containing a heteroatom selected from the hydrocarbon groups defined in (i) containing one or more heteroatoms in the ring or chain, provided that there are no more than two heteroatoms per ten carbon atoms in the group, the heteroatoms being selected from sulfur, nitrogen, oxygen, phosphorus and silicon. The hydrocarbon group containing a heteroatom may be substituted with no more than two non-hydrocarbon substituents and / or one or more hydrocarbon substituents.

[0193] In some embodiments, the term "hydrocarbyl" refers to a group having a carbon atom directly attached to the remainder of the molecule, wherein the group consists of carbon atoms and hydrogen atoms.

[0194] It is known that some of the above substances can interact in the final formulation such that the components of the final formulation can be different from those initially added. For example, metal ions (such as the metal ions of a detergent) can migrate to other acidic or anionic sites of other molecules. The products thus formed, including those formed when the compositions of the present invention are used for their intended uses, may not be easily described. However, all such modifications and reaction products are included within the scope of the present invention. The present invention includes compositions prepared by mixing the above components.

[0195] Example

[0196] The Conductive Layer Deposition Test (CDLT) includes a printed circuit board (PCB) containing a metal of interest (such as copper, aluminum, gold, nickel or any combination), which is arranged in two separate stacked layers, five in an oil solution and five in a vapor space. Each stack contains up to five energized circuits capable of measuring and recording resistance measurements in real time at temperatures up to 250 °C. The formation of the conductive layer results in the detection of an energy flow outside the expected path. This is detected via the induced magnetic field caused by the flow of current. The fluid being tested is contained within a closed vented container. The temperature is measured in the solution and vapor space via two platinum resistance thermometers (PRT). A condenser is used to control the vapor hold. During the test, data is acquired by a data acquisition component and processed by a data processing component. The analysis at the end of the test includes, for example, resistance measurements via energy dispersive X-ray analysis (EDAX), waste oil analysis (ICP), microscopy and elemental analysis of the deposited material. Further details of this test method are disclosed in PCT application WO 2021 / 247428.

[0197] Three lubricant compositions, INV1, INV2, and COMP1, were tested in CLDT to evaluate the role of polyether additives in preventing conductive layer deposits. The compositions of these lubricant compositions are outlined in Table 1.

[0198] Table 1. Lubricant composition

[0199]

[0200] The results of the CLDT for the three lubricant compositions are shown in Table 2. Conductive layer deposits were formed in both the gas phase and solution in COMP1 after a 499-hour test cycle. Those containing INV1 and INV2 did not form conductive layer deposits.

[0201] Table 2. CLDT results 。

[0202]

[0203]

[0204] In addition, the results shown in Table 2 also show that the presence of polyether shows an improvement in gas-phase corrosion at 150 °C as measured by the wire corrosion test disclosed in PCT application WO2021 / 155015.

[0205] Each of the documents mentioned above is incorporated herein by reference. The mention of any document is not an admission that the document constitutes prior art or forms part of the general knowledge of a person skilled in the art in any jurisdiction. Unless otherwise specified in the examples or explicitly stated otherwise, all numerical quantities specifying amounts of substances, reaction conditions, molecular weights, numbers of carbon atoms, etc. in this specification should be understood to be modified by the word "about". It should be understood that the upper and lower limits of the quantities, ranges, and ratios described herein can be combined independently. Similarly, the ranges and amounts of each element of the present invention can be used together with the ranges or amounts of any other element. As used herein, the expression "consisting essentially of" permits the inclusion of substances that do not substantially affect the basic and novel properties of the composition under consideration.

Claims

1. A lubricant composition, the lubricant composition comprising: a. an oil having a lubricating viscosity, b. an amine (thio) phosphate, and c. 0.01% to 5% by weight of a polyether.

2. The lubricant composition according to claim 1, wherein the amine (thio) phosphate comprises: a. an amine salt of an alkyl phosphate, b. an amine salt of an alkyl thiophosphate, c. an amine salt of a dialkyl dithiophosphate, d. an amine salt of an alkyl pyrophosphate, and e. a combination of any one of a), b), c) and d).

3. The lubricant composition according to claim 1, wherein the polyether comprises Formula I: wherein R1 can be a hydrocarbon group having 6 to 30 carbon atoms, R2 can be hydrogen or an alkyl group having 1 to 5 carbon atoms, and R3 can be hydrogen, a C1-C4 alkyl group or -C(O)R4, and wherein R4 can be a C1-C4 alkyl group, and x can be an integer from 10 to 40 (15 to 35 or 20 to 30 or 22 to 26).

4. The lubricant composition according to claim 3, wherein the hydrocarbon group R1 can be a straight-chain aliphatic group having 6 to 30 carbon atoms.

5. The lubricant composition according to claim 3, wherein the hydrocarbon group R1 can be a branched-chain aliphatic group having 6 to 30 carbon atoms.

6. The lubricant composition according to claim 3, wherein the hydrocarbon group R1 can be a straight-chain aliphatic group having 6 to 30 carbon atoms, and R3 can be hydrogen.

7. The lubricant composition according to claim 1, wherein the polyether comprises Formula II: wherein R5 can be a straight-chain or branched-chain aliphatic group having 1 to 30 carbon atoms, in another embodiment 10 to 20 carbon atoms, R2 can be hydrogen or an alkyl group having 1 to 5 carbon atoms, and R3 can be hydrogen, a C1-C4 alkyl group, -C(O)R4, where R4 can be a C1-C4 alkyl group, and n can be an integer from 10 to 40 (15 to 35 or 20 to 30 or 22 to 26), and m can be an integer from 1 to 3.

8. The lubricant composition according to claim 1, wherein the polyether comprises Formula III: wherein the hydrocarbon group R1 can be a straight-chain or branched-chain aliphatic group having 7 to 23 carbon atoms, R2 can be hydrogen or an alkyl group having 1 to 5 carbon atoms, and R3 can be hydrogen, a C1-C4 alkyl group or -C(O)R4, and wherein R4 can be a C1-C4 alkyl group, and n can be an integer from 10 to 40 (15 to 35 or 20 to 30 or 22 to 26).

9. The lubricant composition according to claim 1, the lubricant composition further comprising a thiadiazole.

10. The lubricant composition according to claim 9, wherein the thiadiazole comprises 1,3,4-thiadiazole.

11. The lubricant composition according to claim 10, wherein the 1,3,4-thiadiazole comprises substituents at the 2-position and 5-position of the thiadiazole ring structure.

12. The lubricant composition according to claim 10, wherein the 2-position and 5-position of the thiadiazole ring structure are alkyldithioalkyl moieties.

13. The lubricant composition according to claim 9, wherein the thiadiazole compound has the following formula: wherein R1 and R2 are independently alkyl groups having 1 to 12 carbons.

14. The lubricant composition according to claim 1, wherein the lubricant composition further comprises a dispersant.

15. The lubricant composition according to claim 14, wherein the dispersant comprises a succinimide dispersant.

16. The lubricant composition according to claim 15, wherein the dispersant comprises a polyisobutylene succinimide dispersant.

17. The lubricant composition according to claim 15, wherein the dispersant comprises a grafted olefin copolymer.

18. The lubricant composition according to claim 15, wherein the dispersant is post-treated with boron.

19. The lubricant composition according to claim 15, wherein the dispersant is post-treated with dimercaptothiadiazole.

20. The lubricant composition according to claim 15, wherein the dispersant is post-treated with terephthalic acid.

21. The lubricant composition according to claim 15, wherein the dispersant is post-treated with phosphoric acid.

22. The lubricant composition according to claim 14, wherein the dispersant comprises a succinate ester.

23. The lubricant composition according to claim 14, wherein the dispersant is post-treated with polyvinylamine.

24. The lubricant composition according to claim 14, wherein the dispersant is post-treated with dimercaptothiadiazole.

25. The lubricant composition according to claim 1, wherein the lubricant composition further comprises an antioxidant.

26. The lubricant composition according to claim 25, wherein the antioxidant comprises a hindered phenol antioxidant.

27. The lubricant composition according to claim 25, wherein the antioxidant comprises a hindered amine antioxidant.

28. The lubricant composition according to claim 1, wherein the lubricant composition further comprises a dispersant viscosity modifier.

29. The lubricant composition according to claim 28, wherein the dispersant viscosity modifier comprises a dispersant poly(meth)acrylate.

30. The lubricant composition according to claim 29, wherein the dispersant viscosity modifier comprises a dispersant ethylene / propylene copolymer.

31. The lubricant composition according to claim 1, wherein the lubricant composition further comprises a detergent.

32. The lubricant composition according to claim 1, wherein the lubricant composition further comprises an antiwear additive.

33. The lubricant composition according to claim 32, wherein the antiwear additive comprises a phosphite hydrocarbon ester.

34. The lubricant composition according to claim 32, wherein the antiwear additive comprises a bisacrylamide-coupled dithiophosphate.

35. The lubricant composition according to claim 32, wherein the antiwear additive comprises a dithiophosphate.

36. A method for minimizing conductive deposits in a propulsion system of an electric or hybrid vehicle, the method comprising: Apply a lubricant comprising the lubricant composition according to any one of the preceding claims to the propulsion system, and operate the propulsion system.

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