Phosphorylation dispersants in fluids for electric vehicles

Abstract

To provide a powertrain lubricant composition for electric vehicles, which has desired wear performance, corrosion compatibility of copper, and electrical resistivity of a lubricant, and a method for improving electrical resistivity of a lubricant composition for the electric vehicles.SOLUTION: The lubricant composition for use in the electric vehicles has an oil that has lubricating viscosity and at least one phosphorylated succinimide dispersant that exhibits increased resistivity after aging.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to a lubricating fluid for an electric motor system and a method of lubricating gears within an electric motor system and cooling the motor. In particular, the disclosed technology relates to a lubricating fluid for use in electric vehicles, the lubricating fluid comprising an oil of lubricating viscosity and at least one phosphorus-containing dispersant having between 2.0 wt% and 3.5 wt% phosphorus. The lubricating fluid has a resistivity after aging of at least 50 MΩ·m when measured at 30 °C according to the modified version of ASTM D2624-15.

Summary of the Invention

Problems to be Solved by the Invention

[0002] The main challenges in developing a power train lubricant for electric vehicles are to achieve wear performance, suppress copper corrosion, and ensure the compatibility of the lubricant with charged components within the power train over the life of the lubricant. For example, gears within the electric vehicle's power train require excellent wear protection. Additionally, the copper present in the charged components of the electric motor requires protection at elevated temperatures. Further, the electrical resistivity of the lubricant needs to remain relatively high throughout the life of the lubricant to prevent electrostatic accumulation and discharge of charged components.

[0003] Despite advancements in lubricant technology for electric vehicle power trains, there is a need for an electric vehicle power train lubricant composition having the desired wear performance, copper corrosion compatibility, and electrical resistivity of the lubricant.

[0004] <00000In one embodiment or aspect, a lubricating composition for use in an electric vehicle or a hybrid electric vehicle is described herein. In one embodiment, the lubricating composition comprises at least 95 wt percent of a lubricating base oil composition comprising a base oil selected from API Group III base oils, or a blend of a Group III base oil and a Group II base oil, a Group V base oil, or a mixture thereof, and a phosphate succinimide dispersant containing 2 wt% to 3.5 wt% phosphorus, which provides the lubricating composition with 650 ppm or less of phosphorus, the lubricating composition having 700 ppm or less of total phosphorus, the phosphate succinimide dispersant providing at least 70% of the total phosphorus, the lubricating composition having a kinematic viscosity of 3 cSt to 6.5 cSt at 100°C, and the fluid being aged at 150°C according to JIS K2514-1, ASTM When measured at 1.5 volts and 30°C according to D2624-15, it has a resistivity of at least 50 MΩ·m, and if the lubricating base oil composition contains an API Group V base oil, the API Group V base oil is present in an amount of up to 15% by weight based on the total lubricating composition, and if the lubricating base oil composition contains an API Group II base oil, the API Group II base oil is present in an amount of up to 80% by weight based on the total lubricating composition.

[0005] In other embodiments, the lubricating composition comprises a first dispersant being a phosphated succinimide dispersant, and further comprising a second dispersant containing 0.2% to 0.4% by weight of phosphorus, wherein the second dispersant provides the lubricating composition with 50 ppm or less of phosphorus, and / or the phosphated succinimide dispersant contains 2.5% to 3.0% by weight of phosphorus.

[0006] In yet another embodiment, any lubricating composition according to this specification may contain a phosphated succinimide dispersant that provides 115 ppm to 600 ppm of phosphorus to the lubricating composition, and / or the phosphated succinimide dispersant provides 115 ppm to 250 ppm of phosphorus to the lubricating composition, and / or the first dispersant delivers 115 ppm to 250 ppm of phosphorus to the lubricating composition, the second dispersant delivers 40 ppm or less of phosphorus to the lubricating composition, and / or the phosphated succinimide dispersant provides 250 ppm or less of phosphorus to the lubricating composition, and the lubricating composition has a total phosphorus of 300 ppm or less.

[0007] In yet another embodiment, any lubricating composition according to this specification may have a resistivity of at least 115 MΩ·m after the fluid has been aged at 150°C according to JIS K2514-1.

[0008] In other embodiments, any lubricating composition according to this specification may have a base oil composition selected from API group III base oils or API group II base oils combined with a mixture of API group II base oils and group III base oils.

[0009] In another embodiment, any lubricating composition according to this specification may include a phosphate succinimide dispersant that provides phosphorus between 115 ppm and 250 ppm to the lubricating composition, wherein the lubricating composition has a total phosphorus of 160 ppm to 300 ppm, a kinematic viscosity of 5.5 cSt to 6.0 cSt at 100°C, and a resistivity of 115 MΩ·m or more after the fluid has been aged at 150°C according to JIS K2514-1.

[0010] Another aspect or embodiment of this disclosure provides a method for improving the electrical resistivity of a lubricating composition in an electric vehicle or a hybrid electric vehicle. One approach involves providing a lubricating oil for an electric or hybrid electric vehicle powertrain having a lubricating composition comprising: a lubricating base oil composition comprising at least 95 wt percent lubricating base oil composition comprising an API group III base oil, or a base oil selected from a blend of an API group III base oil and an API group II base oil, an API group V base oil, or a mixture thereof; and a phosphate succinimide dispersant containing 2 wt% to 3.5 wt% phosphorus, which provides the lubricating composition with 650 ppm or less phosphorus, wherein the lubricating composition has 700 ppm or less phosphorus, the phosphate succinimide dispersant provides at least 70% of the total phosphorus, and the lubricating oil has a kinematic viscosity of 3 cSt to 6.5 cSt at 100°C, and after the fluid has been aged at 150°C according to JIS K2514-1, the lubricating composition is used at 1.5 volts and 30°C, according to ASTM When measured according to D2624-15, the resistivity is at least 50 MΩ·m, and if the lubricating base oil composition contains an API Group V base oil, the API Group V base oil is present in an amount of up to 15% by weight based on the total lubricating composition, and if the lubricating base oil composition contains an API Group II base oil, the API Group II base oil is present in an amount of up to 80% by weight based on the total lubricating composition.

[0011] In other embodiments of this method, the lubricating composition comprises a first dispersant being a phosphated succinimide dispersant, and further comprising a second dispersant containing 0.2% to 0.4% by weight of phosphorus, wherein the second dispersant provides the lubricating composition with 50 ppm or less of phosphorus, and / or the phosphated succinimide dispersant contains 2.5% to 3.0% by weight of phosphorus.

[0012] In yet another embodiment of any method herein, a phosphated succinimide dispersant provides the lubricating composition with 115 ppm to 600 ppm of phosphorus, and / or the phosphated succinimide dispersant provides 115 ppm to 250 ppm of phosphorus, and / or the first dispersant delivers 115 ppm to 250 ppm of phosphorus to the lubricating composition, the second dispersant delivers 40 ppm or less of phosphorus to the lubricating composition, and / or the phosphated succinimide dispersant provides 250 ppm or less of phosphorus to the lubricating composition, and the lubricating composition has a total phosphorus of 300 ppm or less.

[0013] In yet another embodiment of the optional method, the lubricating composition has a resistivity of at least 115 MΩ·m after the fluid has been aged at 150°C according to JIS K2514-1, the base oil composition is selected from API group III base oils or a blend of API group II and III base oils or a mixture thereof, a phosphorylated succinimide dispersant provides 115 ppm to 250 ppm of phosphorus to the lubricating composition, and after the fluid has been aged at 150°C according to JIS K2514-1, the lubricating composition has a total phosphorus of 160 ppm to 300 ppm, a kinematic viscosity of 5.5 cSt to 6.0 cSt at 100°C, and a resistivity of at least 115 MΩ·m.

[0014] In yet another embodiment, the disclosure provides the use of a lubricating composition comprising a phosphated succinimide dispersant to improve the electrical resistivity durability of the lubricating composition in a hybrid or electric vehicle, the lubricating composition being described above and in any embodiment herein. In yet another embodiment, the use of a lubricating composition comprising a phosphated succinimide dispersant as described in any embodiment herein is provided in a hybrid or electric vehicle to achieve a resistivity of at least 50 MΩ·m after the fluid has been aged at 150°C according to JIS K2514-1. In yet another embodiment, the use of a lubricating composition comprising a phosphated succinimide dispersant as described in any embodiment herein is described in a hybrid or electric vehicle to reduce wear marks and / or reduce the copper corrosivity of the lubricating composition to achieve at least one of at least 50 MΩ·m resistivity after the fluid has been aged at 150°C according to JIS K2514-1.

[0015] Other embodiments of the present disclosure will become apparent to those skilled in the art from the discussion herein and the practice of the invention disclosed herein.

[0016] To clarify the meaning of specific terms used herein, the following definitions are provided.

[0017] "Lubricating oil," "lubricating composition," "lubricant," and "lubricating and cooling fluid" refer to a finished lubrication product comprising a primary amount of base oil and a small amount of additive composition.

[0018] As used herein, the terms “additive package,” “additive concentrate,” “additive composition,” and “transmission fluid additive package” refer to a portion of a lubricating oil composition excluding the main amount of base oil.

[0019] As used herein, the terms “hydrocarbyl substituent” or “hydrocarbyl group” are used in the ordinary sense known to those skilled in the art. Specifically, they refer to groups having carbon atoms directly bonded to the rest of the molecule and having primarily hydrocarbon properties. Each hydrocarbyl group is independently selected from hydrocarbon substituents, the substituted hydrocarbon substituents containing one or more of the following: halo, hydroxyl, alkoxy, mercapto, nitro, nitroso, amino, pyridyl, furyl, imidazolyl, oxygen, and nitrogen, with no more than two non-hydrocarbon substituents for every 10 carbon atoms in the hydrocarbyl group.

[0020] As used herein, the term “weight percent” means the percentage of the listed ingredient relative to the total weight of the composition, unless otherwise explicitly stated.

[0021] As used herein, the terms “soluble,” “oil-soluble,” and “dispersible” may indicate, but do not necessarily, that a compound or additive is soluble, soluble, miscible, or suspendable in oil in any proportion. However, the aforementioned terms mean that they are soluble, suspendable, soluble, or stably dispersible in oil to a degree sufficient to exert their intended effect in the environment in which the oil is extracted. Furthermore, higher levels of formulation of a particular additive may be possible by incorporating other additives as needed.

[0022] As used herein, the term "alkyl" refers to linear, branched, cyclic, and / or substituted saturated chain portions of approximately 1 to approximately 200 carbon atoms.

[0023] As used herein, the term “alkenyl” refers to a linear, branched, cyclic, and / or substituted unsaturated chain portion consisting of approximately 3 to approximately 30 carbon atoms.

[0024] As used herein, the term "aryl" refers to monocyclic and polycyclic aromatic compounds that may contain alkyl, alkenyl, alkylaryl, amino, hydroxyl, alkoxy, halo substituents, and / or heteroatoms including, but not limited to, nitrogen and oxygen.

[0025] As used herein, "number average molecular weight" or "Mn" is determined by gel permeation chromatography (GPC) using commercially available polystyrene standards (with Mn ranging from 180 to about 18,000 as calibration standards).

[0026] Throughout this disclosure, terms such as "comprises," "includes," "contains," etc. are considered to be without limitation and include any element, step, or component not expressly recited. The phrase "consists essentially of" means including any element, step, or component expressly listed, as well as any additional element, step, or component that does not materially affect the basic and novel aspects of the invention. This disclosure also contemplates that any composition described using the terms "comprises," "includes," "contains" should also be construed to include the disclosure of the same composition "consisting essentially of" or "consisting of" its specifically recited components.

Mode for Carrying Out the Invention

[0027] According to an exemplary embodiment, a lubricating fluid is described herein for use in an electric vehicle or a hybrid electric vehicle, comprising a base oil and at least one phosphorylated succinimide dispersant having 2.0 wt% to 3.5 wt% phosphorus. In one embodiment, the phosphorylated succinimide dispersant having 2.0 wt% to 3.5 wt% phosphorus delivers less than 650 ppm phosphorus to the lubricating fluid. In other embodiments, the phosphorylated succinimide dispersant has 2.5 wt% to 3.2 wt% phosphorus, in yet other embodiments 2.8 wt% to 3.2 wt% phosphorus, and in yet another embodiment about 3 wt% phosphorus. In any embodiment herein, the phosphorylated succinimide dispersant may provide up to 650 ppm phosphorus, up to 600 ppm phosphorus, up to 500 ppm phosphorus, up to 400 ppm phosphorus, up to 300 ppm phosphorus, or up to 250 ppm phosphorus to the fluid. In other embodiments, the phosphorylated succinimide dispersant may provide at least 100 ppm phosphorus, at least 120 ppm phosphorus, or at least 150 ppm phosphorus to the fluid herein.

[0028] The fluid herein may also contain other phosphorus sources, but the total phosphorus content of the fluid may be 700 ppm or less, 650 ppm or less, 600 ppm or less, 550 ppm or less, 500 ppm or less, 450 ppm or less, 400 ppm or less, 350 ppm or less, 300 ppm or less, 250 ppm or less, or 200 ppm or less. The fluid may also contain a total phosphorus amount of 100 ppm or more. In embodiments having other phosphorus sources, the phosphorus provided by the phosphorylated succinimide dispersant provides at least about 70%, at least about 75%, at least about 80%, at least about 90%, or at least about 92% of the total phosphorus amount. In other approaches, the phosphorus provided by the phosphorylated succinimide dispersant provides 100% or less, 98% or less, 95% or less, or 90% or less of the total phosphorus amount.

[0029] As further described below, the fluids of this specification, comprising a base oil and at least one phosphorylated succinimide dispersant, generally have a kinematic viscosity of 3 cSt to 6.5 cSt at 100°C and a resistivity of at least 50 MΩ·m when measured according to ASTM D2624-15 (at 1.5 volts and 30°C, using the lubricating composition, as described herein) after the fluids have been aged at 150°C according to JIS K2514-1.

[0030] Base oil - Suitable base oils for use in formulating lubricating fluids for use in electric and hybrid vehicles according to this disclosure may be selected from suitable synthetic or natural oils or mixtures thereof having a suitable lubricating viscosity.

[0031] Natural oils may include animal oils and vegetable oils (e.g., castor oil, lard), as well as liquid petroleum and mineral oils such as paraffinic, naphthenic, or mixed paraffin-naphthenic solvent-treated or acid-treated mineral lubricants.

[0032] Oils derived from coal or shale may also be suitable. Furthermore, oils obtained from the Fischer-Tropsch gas-liquid process are also suitable. Fischer-Tropsch synthetic hydrocarbons are produced from synthesis gas containing H2 and CO using a Fischer-Tropsch catalyst. Such hydrocarbons typically require further processing for use as base oils. These types of oils are generally called natural gas liquefied fuels (GTLs). For example, hydrocarbons may be hydrogen-isomerized using the processes disclosed in U.S. Patent No. 6,103,099 or No. 6,180,575, or hydrocracking and hydrogen-isomerized using the processes disclosed in U.S. Patent No. 4,943,672 or No. 6,096,940, or dewaxed using the process disclosed in U.S. Patent No. 5,882,505, or hydroisomerized and dewaxed using the processes disclosed in U.S. Patent No. 6,013,171, No. 6,080,301, or No. 6,165,949. The base oil may have a kinematic viscosity of 2 to 15 cSt at 100°C, as measured by ASTM D2270-10 (2016).

[0033] The base oils used in the present invention as described herein may be a single base oil or a mixture of two or more base oils. Specifically, one or more base oils may preferably be selected from any of the Group II to V base oils specified in the American Petroleum Institute (API) Base Oil Interoperability Guidelines. In some embodiments, the base oil is a Group III base oil or a Group III base oil combined with one or more Group II or Group V base oils. Such base oil groups are shown in Table 1 below.

[0034] [Table 1]

[0035] In one variant, in any of the embodiments described above, the base oil may be selected from base oils of Group II to Group V, or a mixture of these base oils. In one embodiment, the base oil comprises a base oil of Group III, or a blend of a base oil of Group III and a base oil of Group II and / or Group V. In one embodiment, the lubricating composition comprises at least 75% by weight of a base oil of Group II and / or Group III. In another embodiment, the lubricating composition comprises at least 90% by weight of a base oil of Group III. In yet another embodiment, the lubricating composition comprises at least 10% by weight of a base oil of Group V.

[0036] In yet another embodiment, if the lubricating composition contains a base oil of group V, the group V base oil is present in the lubricating composition in an amount ranging from at least about 5% by weight, at least about 8% by weight, or at least about 10% by weight, and / or up to 20% by weight, up to 15% by weight, or up to 12% by weight (the remainder being a base oil of group III). In yet another embodiment, if the lubricating composition contains a base oil of group II, the group II base oil is present in the lubricating composition in an amount ranging from at least about 50% by weight, at least about 75% by weight, or at least about 77% by weight, and / or up to 80% by weight, up to 78% by weight, or up to 77% by weight (the remainder being a base oil of group II and / or group V).

[0037] Group V base oils include synthetic and natural ester base oils. Synthetic esters may include esters of dicarboxylic acids and monohydric alcohols. Specific examples of these esters include dibutyl adipate, di(2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate, diicosyl sebacate, and 2-ethylhexyl diester of linoleic acid dimers. Other Group V esters include C5-C 12This also includes those produced from monocarboxylic acids and polyols and polyol ethers, such as neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol, and tripentaerythritol. Esters are also monoesters of monocarboxylic acids and monohydric alcohols.

[0038] Natural esters refer to materials derived from renewable biological resources, organisms, or entities, as opposed to materials derived from petroleum or equivalent raw materials. Natural esters include fatty acid triglycerides, hydrolyzed or partially hydrolyzed triglycerides, or transesterified triglyceride esters such as fatty acid methyl esters (or FAMEs). Suitable triglycerides include, but are not limited to, palm oil, soybean oil, sunflower oil, rapeseed oil, olive oil, linseed oil, and related materials.

[0039] Base oils can be combined with additive compositions, such as those disclosed in the embodiments herein, to provide a lubricating fluid for use in electric vehicles. Thus, base oils may be present in the lubricating fluids described herein in an amount exceeding about 90% by weight, based on the total weight of the lubricating fluid composition. In some embodiments, base oils may be present in the lubricating fluid in an amount exceeding about 95% by weight, based on the total weight of the lubricating fluid.

[0040] Additive composition Phosphorylated succinimide dispersant: The lubricating fluids described herein include at least one phosphorylated succinimide dispersant.

[0041] Hydrocarbyl dicarboxylic acids or anhydrides reacted with polyalkylene polyamines are used to produce succinimide dispersants. Succinimide dispersants and their preparations are disclosed, for example, in U.S. Patents 7,897,696 and 4,234,435, which are incorporated herein by reference. The hydrocarbyl portion of the hydrocarbyl dicarboxylic acid or its anhydride can be derived from butene polymers, such as polymers of isobutylene. Suitable polyisobutenes for use herein include those formed from polyisobutylene or highly reactive polyisobutylene having at least about 60% terminal vinylidene content, such as about 70% to about 90% or more. Suitable polyisobutenes may include those prepared using a BF3 catalyst.

[0042] The number-average molecular weight of polyisobutylene substituents, when measured by gel permeation chromatography (GPC) using polystyrene (number-average molecular weight 180 to approximately 18,000) as the calibration standard, can vary over a wide range, for example, from 500 to 5000. Additionally, the GPC method provides molecular weight distribution information; see, for example, WWYau, JJKirkland and DDBly, “Modern Size Exclusion Liquid Chromatography,” John Wiley and Sons, New York, 1979, also incorporated herein by reference.

[0043] The polyisobutylene portion in the dispersant preferably has a polydispersity index (PDI) determined by the ratio of the weight-average molecular weight (Mw) to the log-average molecular weight (Mn). Polymers having an Mw / Mn of less than 2.2, preferably less than 2.0, are most desirable. Suitable polyisobutylene substituents have a polydispersity of about 1.5 to 2.1, or about 1.6 to about 1.8.

[0044] Dicarboxylic acids or anhydrides include maleic anhydride, maleic acid, fumaric acid, malic acid, tartaric acid, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride, mesaconic acid, ethyl maleic acid, anhydride, The reactants can be selected from carboxylic acid-based reactants including dimethyl maleic anhydride, ethyl maleic acid, dimethyl maleic acid, hexyl maleic acid, and corresponding acid halides or C1-C4 aliphatic esters. The molar ratio of the dicarboxylic acid or anhydride to the hydrocarbyl moiety in the reaction mixture used to produce the hydrocarbyl dicarboxylic acid or anhydride may vary considerably. Thus, the molar ratio can vary from 5:1 to 1:5, for example, from 3:1 to 1:3. A molar ratio of acid or anhydride to hydrocarbyl moiety of 1:1 to less than 1.6:1 is particularly preferred. Other useful molar ratios of dicarboxylic acid or anhydride to hydrocarbyl moiety are 1:1 to 1.7:1, or 1:1 to 1.6:1, or 1:1 to 1.5:1.

[0045] Any of the numerous polyalkylene polyamines can be used in the preparation of dispersant additives. Non-limiting exemplary polyamines include aminoguanidine bicarbonate (AGBC), diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), pentaethylenehexamine (PEHA), and heavy polyamines. Heavy polyamines may include mixtures of polyalkylene polyamines that have small amounts of polyamine oligomers, such as TEPA and PEHA, but primarily have oligomers with seven or more nitrogen atoms and two or more primary amines per molecule, and have a broader branching range than conventional polyamine mixtures. Generally, these heavy polyamines have an average of 6.5 nitrogen atoms per molecule. Additional non-limiting polyamines that may be used to prepare hydrocarbyl-substituted succinimide dispersants are disclosed in U.S. Patent No. 6,548,458, the entire disclosure of which is incorporated herein by reference. The molar ratio of hydrocarbyl dicarboxylic acid or anhydride to polyalkylene polyamine may be approximately 1:1 to approximately 3:1.

[0046] The dispersants described herein are phosphorylated. These dispersants are generally reaction products of at least one phosphorus compound and at least one ashless succinimide dispersant, as described above.

[0047] Suitable phosphorus compounds for forming dispersants in this specification include phosphorus compounds or mixtures of phosphorus compounds that can introduce phosphorus-containing species into the ashless dispersant. Therefore, either organic or inorganic phosphorus compounds capable of such reactions can be used. Accordingly, such inorganic phosphorus compounds can be used as inorganic phosphoric acid and inorganic phosphorus oxides, including its hydrates. Typical organophosphorus compounds include complete and partial esters of phosphoric acid, such as mono, di, and triesters of phosphoric acid, thiophosphate, dithiophosphate, trithiophosphate, and tetrathiophosphate; mono, di, and triesters of phosphoric acid, thiophosphate, dithiophosphate, and trithiophosphate; trihydrocarbyl phosphine oxide, trihydrocarbyl phosphine sulfide; mono and dihydrocarbyl phosphonates (RPO(OR′)(OR″), where R and R′ are hydrocarbyl and R″ is a hydrogen atom or a hydrocarbyl group); as well as their mono, di, and trithio analogs; mono and dihydrocarbyl phosphonates (RP(OR′)(OR″), where R and R′ are hydrocarbyl and R″ is a hydrogen atom or a hydrocarbyl group); as well as their mono and dithio analogs. Therefore, such compounds include, for example, phosphorous acid (H3PO3, sometimes represented as H2(HPO3), and sometimes called ortho-phosphorous acid or phosphonic acid), phosphoric acid (H3PO4, sometimes called ortho-phosphoric acid), subphosphoric acid (H4P2O6), metaphosphoric acid (HPO3), pyrophosphoric acid (H4P2O7), subphosphorous acid (H3PO2, sometimes called phosphinic acid), pyrosulfite (H4P2O5, sometimes called pyrophosphonic acid), phosphinic acid (H3PO), and tripolyphosphate (H5P3O 10 ), tetrapolyphosphate (H5P4O 13It can be used as phosphorotetrathio (H3PS4) acid, phosphoromonothio acid (H3PO3S), phosphorodithio acid (H3PO2S2), phosphorotrithio acid (H3POS3), tetraphosphorus trisulfide, heptaphosphorus sulfide, and pentasulfide (P2S5, P4S2). 10 Partial or whole sulfur analogs such as (sometimes referred to as) can also be used to form dispersants for the present disclosure. Inorganic phosphorus halogens such as PCl3, PBr3, POCl3, and PSCl3 can also be used.

[0048] Similarly, organophosphorus compounds such as mono, di, and triesters of phosphoric acid (e.g., trihydrocarbyl phosphate, dihydrocarbyl monoacid phosphate, monohydrocarbyl diacid phosphate, and mixtures thereof), mono, di, and triesters can be used; phosphorous acid (e.g., trihydrocarbyl phosphite, dihydrocarbyl hydrogen phosphite, hydrocarbyl diacid phosphite, and mixtures thereof); and esters of phosphonic acids (both "primary," RP(O)(OR)2, and "secondary"). The whole-sulfur or partially-sulfur analogs of any of the aforementioned organophosphorus compounds, such as R2P(O)(OR)), esters of phosphinic acids, phosphonyl halides (e.g., RP(O)Cl2 and R2P(O)Cl), halophosphates (e.g., (RO)PCl2 and (RO)2PCl), halophosphates (e.g., ROP(O)Cl2 and (RO)2P(O)Cl), tertiary pyrophosphate esters (e.g., (RO)2P(O)-OP(O)(OR)2), and all-sulfur or partially-sulfur analogs of any of the aforementioned organophosphorus compounds, wherein each hydrocarbyl group contains up to about 100 carbon atoms, preferably up to about 50 carbon atoms, more preferably up to about 24 carbon atoms, all or partially-sulfur analogs of any of the aforementioned organophosphorus compounds, and most preferably up to about 12 carbon atoms. Haloidal halophosphines (e.g., tetrahalohydrocarbyl phosphate, trihalodihydrocarbyl phosphate, and dihalotrihydrocarbyl phosphate) and halophosphines (monohalophosphines and dihalophosphines) can also be used.

[0049] In the embodiment, the phosphorylated dispersant is a reaction product of succinimide molecules and a phosphorus source. In one example, polyisobutyl succinimide (PIBSI) or other suitable succinimide is heated to about 100°C. Next, phosphorous acid or other phosphorus source is added under a slight vacuum (700 mm Hg) and held for 30 minutes to 1 hour (to remove moisture). Then, the temperature is slowly raised to about 160°C and held for about 2 hours. Finally, the solution is placed under vacuum and held for a further 1-2 hours to form the phosphorylated succinimide dispersant.

[0050] In some embodiments, the succinimide dispersant may also be further post-treated with a boron source. Suitable boron compounds useful for forming dispersants herein include any boron compound or mixture of boron compounds that can introduce a boron-containing species into the ashless dispersant. Any organic or inorganic boron compound that can undergo such a reaction can be used. Thus, boron oxide, boron oxide hydrate, boron trifluoride, boron tribromide, boron trichloride, HBF4 boric acid, for example, boronic acids (e.g., alkyl-B(OH)2, or aryl-B(OH)2), boric acid (i.e., H3BO3), tetraboric acid (i.e., H2B5O7), metaboric acid (i.e., HBO2), ammonium salts of such boric acid, and esters of such boric acid can be used. The use of complexes of boron trihalides with ethers, organic acids, inorganic acids, or hydrocarbons is a convenient means of introducing boron reactants into the reaction mixture. Such complexes are known and are exemplified by boron trifluoride-diethyl ether, boron trifluoride-phenol, boron trifluoride-phosphate, boron trichloride-chloroacetic acid, boron tribromide-dioxane, and boron trifluoride-methyl ethyl ether.

[0051] In some approaches, the dispersant used in the present disclosure comprises a polyisobutenyl moiety having a number average molecular weight in the range of about 800–2500, or 900–1200, or 975–1175, and is present in the lubricating fluid in an amount sufficient to supply nitrogen greater than 50 ppm, greater than 100 ppm, greater than 250 ppm, 50–300 ppm, 50–120 ppm, or 120–300 ppm.

[0052] The dispersant used in the present invention is present in the lubricating fluid in an amount sufficient to deliver phosphorus of more than 100 ppm, or more than 200 ppm, or more than 550 ppm, or 100 to 700 ppm, or 100 to 300 ppm, or 300 to 700 ppm.

[0053] In one embodiment, the dispersant of the present invention as described herein may be obtained from an HR-PIB having Mn of 975 to 1175, Mw of 1700 to 2100, and in some approaches a PDI of 1.8 or less. Furthermore, the dispersant may have a molar ratio of (A) polyisobutenyl-substituted succinic anhydride to (B) polyamine in the range of 4:3 to 5:2, and a phosphorus content between 2.5% to 3.25% by weight.

[0054] As shown in the examples herein, when a succinimide dispersant having 2.0% to 3.5% by weight (in other embodiments, 2.5 to 3.2% by weight, 2.8 to 3.2% by weight, or about 3% by weight) of phosphorus is present in the lubricating fluid in an amount that delivers 100 to 650 ppm of phosphorus (or other ranges disclosed herein), the resulting composition has increased electrical resistivity and good wear protection and copper compatibility, even after aging.

[0055] Other additives: The lubricating fluids described herein may also contain one or more components selected from the group including antioxidants, friction modifiers, cleaning agents, corrosion inhibitors, copper corrosion inhibitors, defoamers, seal swelling agents, extreme pressure agents, wear inhibitors, viscosity modifiers, additional dispersants, and combinations thereof. Other performance additives, in addition to those specified above, may also contain one or more of metal deactivators, deemulsifiers, pour point depressants, and mixtures thereof.

[0056] Antioxidants: In some embodiments, the lubricating fluid contains another antioxidant. Suitable antioxidants include, among others, phenolic antioxidants, aromatic amine antioxidants, sulfurized phenolic antioxidants, and organic phosphites.

[0057] Examples of phenolic antioxidants include 2,6-di-tert-butylphenol, liquid mixtures of tertiary butylated phenols, 2,6-di-tert-butyl-4-methylphenol, 4,4'-methylenebis(2,6-di-tert-butylphenol), 2,2'-methylenebis(4-methyl-6-ter-t-butylphenol), and mixed methylene crosslinked polyalkylphenols, and 4,4'-thiobis(2-methyl-6-tert-butylphenol). Other examples include N,N'-di-sec-butylphenylenediamine, 4-isopropylaminodiphenylamine, phenyl-alpha-naphthylamine, phenyl-alpha-naphthylamine, and cyclic alkylated diphenylamines. Examples include sterically hindered tertiary butylated phenols, bisphenols, and cinnamic acid derivatives, as well as combinations thereof.

[0058] Aromatic amine antioxidants include, but are not limited to, diarylamines having the following formula. [ka] In the formula, R' and R'' each independently represent a substituted or unsubstituted aryl group having 6 to 30 carbon atoms. Examples of substituents on aryl groups include alkyl, hydroxyl, halogen, carboxylic acid or ester groups, or aliphatic hydrocarbon groups such as nitro groups, all having 1 to 30 carbon atoms.

[0059] The aryl group is preferably a substituted or unsubstituted phenyl or naphthyl group, particularly one or both aryl groups being substituted with at least one alkyl group having 4 to 30 carbon atoms, preferably 4 to 18 carbon atoms, most preferably 4 to 9 carbon atoms. It is preferable that one or both aryl groups are substituted with, for example, mono-alkylated diphenylamine, di-alkylated diphenylamine, or a mixture of mono- and di-alkylated diphenylamine.

[0060] Examples of diarylamines that can be used include, but are not limited to, diphenylamine, various alkylated diphenylamines, 3-hydroxydiphenylamine, N-phenyl-1,2-phenylenediamine, N-phenyl-1,4-phenylenediamine, monobutyldiphenylamine, dibutyldiphenylamine, monooctyldiphenylamine, dioctyldiphenylamine, monononyldiphenylamine, dinonyldiphenylamine, monotetradecyldiphenylamine, ditetradecyldiphenylamine, phenyl-alpha-naphthylamine, monooctylphenyl-alpha-naphthylamine, phenyl-beta-naphthylamine, monoheptyldiphenylamine, diheptyldiphenylamine, p-oriented styrene-diphenylamine, mixed butyloctyldiphenylamine, and mixed octylstyryldiphenylamine.

[0061] Sulfur-containing antioxidants include, but are not limited to, sulfurized olefins, characterized by the type of olefin used in their production and the final sulfur content of the antioxidant. High molecular weight olefins, i.e., olefins having an average molecular weight of 168 to 351 g / mol, are preferred. Examples of usable olefins include alpha-olefins, isomerized alpha-olefins, branched olefins, cyclic olefins, and combinations thereof.

[0062] Examples of alpha-olefins include, but are not limited to, any C4-C25 alpha-olefins. Alpha-olefins can be isomerized before or during the sulfidation reaction. Structural and / or conformational isomers of alpha-olefins containing internal double bonds and / or branching can also be used. For example, isobutylene is the branched olefin counterpart of alpha-olefin 1-butene.

[0063] Sulfur sources that can be used in the sulfidation reactions of olefins include elemental sulfur, sulfur monochloride, sulfur dichloride, sodium sulfide, sodium polysulfide, and mixtures of these that are added together at different stages of the sulfidation process.

[0064] Unsaturated oils may be sulfurized and used as antioxidants due to their unsaturation. Examples of usable oils and fats include corn oil, canola oil, cottonseed oil, grapeseed oil, olive oil, palm oil, peanut oil, coconut oil, rapeseed oil, safflower seed oil, sesame oil, soybean oil, sunflower seed oil, animal fat, and combinations thereof.

[0065] The total amount of antioxidants in the lubricating fluids described herein may be present in amounts that deliver up to 200 ppm of nitrogen, or up to 100 ppm of nitrogen, or up to 150 ppm of nitrogen, or between 100 and 150 ppm of nitrogen.

[0066] Friction modifiers - Suitable additional friction modifiers include metal-containing and metal-free friction modifiers, which may include imidazolines, aliphatic fatty acid amides, aliphatic amines, succinimides, alkoxylated aliphatic amines, etheramines, alkoxylated etheramines, amine oxides, amidoamines, nitriles, betaines, quaternary amines, imines, amine salts, aminoguanidines, alkanolamides, phosphonates, metal-containing compounds, glycerol esters, sulfurized fatty compounds and olefins, naturally derived animal and vegetable oils such as sunflower oil, dicarboxylic acid esters, esters or partial esters of polyols with one or more aliphatic or aromatic carboxylic acids, etc.

[0067] Suitable friction modifiers may contain hydrocarbyl groups selected from linear, branched, or aromatic hydrocarbyl groups, or mixtures thereof, such hydrocarbyl groups may be saturated or unsaturated. Hydrocarbyl groups may consist of carbon and a heteroatom such as hydrogen or sulfur or oxygen. Hydrocarbyl groups may range from 12 to 25 carbon atoms. In some embodiments, the friction modifier may be a long-chain fatty acid ester. In other embodiments, the long-chain fatty acid ester may be a monoester, diester, or (tri)glyceride. Friction modifiers may also be long-chain fatty amides, long-chain fatty esters, long-chain fatty epoxide derivatives, or long-chain imidazolines.

[0068] Other suitable friction modifiers may include organic, ashless (metal-free), and nitrogen-free organic friction modifiers. Such friction modifiers may include esters formed by reacting carboxylic acids and anhydrides with alkanols, and generally contain polar end groups (e.g., carboxyl or hydroxyl) covalently bonded to lipophilic hydrocarbon chains. Examples of organic ashless nitrogen-free friction modifiers are generally known as glycerol monooleate (GMO), which may include mono-, di-, and tri-esters of oleic acid. Other suitable friction modifiers are described in U.S. Patent No. 6,723,685.

[0069] Amine-based friction modifiers may contain amines or polyamines. Such compounds may have hydrocarbyl groups that are either saturated or unsaturated linear chains, or mixtures thereof, and may contain 12 to 25 carbon atoms. Further examples of suitable friction modifiers include alkoxylated amines and alkoxylated etheramines. Such compounds may have hydrocarbyl groups that are either saturated, unsaturated, or mixtures thereof linear chains. These may contain about 12 to about 25 carbon atoms. Examples include ethoxylated amines and ethoxylated etheramines.

[0070] Amines and amides can be used on their own or as adducts or reaction products with boron compounds such as boron oxide, boron halides, metaborates, boric acid, or mono-, di-, or tri-alkyl borates. Other suitable friction modifiers are described in U.S. Patent No. 6,300,291.

[0071] If the additional friction modifier contains nitrogen, such additional friction modifier may be present in the lubricating fluid in amounts that deliver up to 200 ppm of nitrogen, or up to 150 ppm of nitrogen, or between 100 and 150 ppm of nitrogen.

[0072] Detergents - The metal detergents contained in the lubricating fluids described herein generally consist of a polar head and a long hydrophobic tail, the polar head comprising a metal salt of an acidic organic compound. The salts may contain substantially stoichiometric amounts of metal, in which case they are usually described as ordinary or neutral salts and typically have a total base number or TBN (measured by ASTM D2896) of about 0 to less than about 150. A large amount of metal base can be introduced by reacting an excess of metal compounds, such as oxides or hydroxides, with an acidic gas such as carbon dioxide. The resulting overbasic detergents contain micelles of neutralized detergent surrounding a core of inorganic metal base (e.g., hydrated carbonate). Such overbasic detergents may have a TBN of about 150 or more, for example, about 150 to about 450 or more.

[0073] Suitable cleaning agents for use in this embodiment include oil-soluble overbasic, low-basic, and neutral sulfonates, phenates, sulfide phenates, and salicylates of alkali or alkaline earth metals, such as sodium, potassium, lithium, calcium, and magnesium. More than one metal may be present, for example, both calcium and magnesium. Mixtures of calcium and / or magnesium with sodium may also be suitable. Suitable metal cleaning agents may be overbasic calcium or magnesium sulfonates having a TBN of 150 to 450 TBN, overbasic calcium or magnesium phenates or sulfide phenates having a TBN of 150 to 300 TBN, and overbasic calcium or magnesium salicylates having a TBN of 130 to 350 TBN. Mixtures of such salts may also be used.

[0074] A metal-containing cleaning agent may be present in the lubricating fluid in an amount sufficient to improve the fluid's rust-preventive properties. The metal-containing cleaning agent may be present in the fluid in an amount sufficient to provide up to 300 ppm of alkali and / or alkaline earth metals, based on the total weight of the lubricating fluid. In one example, the metal-containing cleaning agent may be present in an amount sufficient to provide 100–300 ppm of alkali and / or alkaline earth metals. In another embodiment, the metal-containing cleaning agent may be present in an amount sufficient to provide 220–250 ppm of alkali and / or alkaline earth metals.

[0075] Corrosion inhibitors—rust inhibitors or corrosion inhibitors may also be included in the lubricating compositions described herein. Suitable copper corrosion inhibitors include etheramines, polyethoxylated compounds, such as ethoxylated amines and ethoxylated alcohols, imidazolines, monoalkyls, and dialkylthiadiazoles. Additional compounds include monocarboxylic acids and polycarboxylic acids. Suitable monocarboxylic acids include octanoic acid, decanoic acid, and dodecanoic acid. Suitable polycarboxylic acids include dimeric and trimeric acids produced from tall oil fatty acids, oleic acid, linoleic acid, and other acids.

[0076] Thiazoles, triazoles, and thiadiazoles can also be used as lubricants. Examples include benzotriazole, toltriazole, octyltriazole, decyltriazole, dodecyltriazole, 2-mercaptobenzothiazole, 2,5-dimercapto-1,3,4-thiadiazole, 2-mercapto-5-hydrocarbylthio-1,3,4-thiadiazole, and 2-mercapto-5-hydrocarbyldithio-1,3,4-thiadiazole. Preferred compounds are 1,3,4-thiadiazoles, particularly 2-hydrocarbyldithio-5-mercapto-1,3,4-dithiadiazole, many of which are commercially available.

[0077] Other useful types of rust inhibitors include alkenyl succinic acid and alkenyl succinic anhydride corrosion inhibitors, such as tetrapropenyl succinic acid, tetrapropenyl succinic acid anhydride, tetradecenyl succinic acid, tetradecenyl succinic acid anhydride, hexadecenyl succinic acid, and hexadecenyl succinic acid anhydride. Semi-esters of alkenyl succinic acid having 8 to 24 carbon atoms in the alkenyl group with alcohols such as polyglycols are also useful.

[0078] Such mixtures of rust inhibitors or corrosion inhibitors may be used. The total amount of corrosion inhibitors present in the lubricating compositions described herein may be up to 2.0% by weight, or in the range of 0.01 to 1.0% by weight, based on the total weight of the lubricating composition.

[0079] Extreme pressure agents: The lubricating fluids described herein may optionally contain one or more extreme pressure (EP) agents. Oil-soluble (EP) agents include sulfur and chlorosulfur-containing EP agents, chlorinated hydrocarbon EP agents, and phosphorus EP agents. Examples of such EP agents include chlorinated waxes; organic sulfides and polysulfides such as dibenzyl disulfide, bis(chlorobenzyl) disulfide, dibutyl trisulfide, methyl sulfide esters of oleic acid, alkylphenol sulfides, dipentene sulfides, terpenes sulfides, and Diels-Alder sulfide adducts; phosphorus sulfide hydrocarbons such as reaction products of phosphorus sulfide with terpentine or methyl oleate; phosphate esters such as dihydrocarbyl and trihydrocarbyl phosphite, e.g., dibutyl phosphite, diheptyl phosphite, dicyclohexyl phosphite, and pentylphenyl phosphite; dipentylphenyl phosphite, tridecyl phosphite, distearyl phosphite, and polypropylene-substituted phenyl phosphite; metal thiocarbamates such as zinc dioctyldithiocarbamate and barium heptylphenol dioate; amine salts of alkyl and dialkyl phosphates, e.g., amine salts of reaction products of dialkyldithiophosphate and propylene oxide; and mixtures thereof.

[0080] Anti-wear agents: The lubricating oil compositions described herein may optionally contain one or more anti-wear agents. Examples of suitable anti-wear agents include, but are not limited to, metal thiophosphates, metal dialkyldithiophosphates, phosphate esters or their salts, phosphate esters, phosphites, phosphorus-containing carboxylic acid esters, ethers or amides, sulfurized olefins, thiocarbamate esters, alkylene-linked thiocarbamates, and thiocarbamate-containing compounds including bis(S-alkyldithiocarbamyl) disulfide, as well as mixtures thereof. A suitable anti-wear agent may be molybdenum dithiocarbamate. Phosphorus-containing anti-wear agents are described in detail in European Patent No. 612839. The metal in the dialkyldithiophosphate salt may be alkali metals, alkaline earth metals, aluminum, lead, tin, molybdenum, manganese, nickel, copper, titanium, or zinc.

[0081] Further examples of suitable wear-resistant agents include titanium compounds, tartrates, taltrimids, oil-soluble amine salts of phosphorus compounds, sulfurized olefins, phosphates (e.g., dibutyl phosphite), phosphonates, thiocarbamate-containing compounds, such as thiocarbamate esters, thiocarbamate amides, thiocarbamate ethers, alkylene-bonded thiocarbamates, and bis(S-alkyldithiocarbamyl) disulfide. Tartrates or taltrimids may contain alkyl-ester groups, and the total number of carbon atoms on the alkyl group may be at least 8. In one embodiment, the wear-resistant agent may also contain citrates.

[0082] The anti-wear agent may be present in a range of approximately 0% to 15% by weight, in other approaches approximately 0.01% to 10% by weight, in yet another approach approximately 0.05% to 5% by weight, or in a further approach including approximately 0.1% to 3% by weight of the lubricating oil composition.

[0083] Viscosity modifiers - Lubricating fluids may optionally contain one or more viscosity modifiers. Suitable viscosity index modifiers may include polyolefins, olefin copolymers, ethylene / propylene copolymers, polyisobutene, styrene-isoprene polymers, styrene / maleate copolymers, styrene-butadiene copolymers, styrene-isoprene polymers, alpha-olefin maleic anhydride copolymers, polymethacrylates, polyacrylates, polyalkylstyrenes, hydrated alkenylaryl conjugated copolymers, or mixtures thereof. Viscosity index modifiers may also contain star polymers, and suitable examples are described in U.S. Publication No. 2012 / 0101017(A1).

[0084] The lubricating fluids described herein may also optionally contain one or more dispersing viscosity modifiers in addition to, or in place of, the viscosity modifiers. Suitable dispersing viscosity modifiers may include ethylene-propylene copolymers functionalized with a reaction product of a functionalized polyolefin, e.g., an acylation agent (e.g., maleic anhydride) and an amine, amine-functionalized polymethacrylates, or esterified maleic anhydride-styrene copolymers reacted with an amine.

[0085] Viscosity modifiers and / or dispersants: The total amount of viscosity modifiers, if present, may be a maximum of 1.0% by weight, or a maximum of 0.5% by weight, or a maximum of 0.3% by weight, based on the total weight of the lubricating fluid.

[0086] Additional dispersants: The lubricating fluid may contain one more additional dispersant than the phosphorylated succinimide dispersant described above. The additional dispersants are ashless dispersants in which polar groups are bonded to hydrocarbon chains of relatively high molecular weight. Examples of such dispersants include N-substituted long-chain alkenyl succinimides, succinate ester dispersants, succinate ester-amide dispersants, Mannich base dispersants, high molecular weight polyamine dispersants, their phosphorylated forms, and their boronated forms. The dispersants may be capped with acidic molecules that can react with secondary amino groups.

[0087] The N-substituted long-chain alkenyl succinimides may contain polyisobutylene (PIB) substituents, as determined by the GPC method described above, where the number-average molecular weight of the polyisobutylene substituents is in the range of about 500 to 5000. The PIB substituents used in the dispersant also have a viscosity at 100°C of about 2100 to about 2700 cSt, as determined using ASTM D445.

[0088] The polyisobutylene portion in the dispersant preferably has a narrow molecular weight distribution (MWD), also known as polydispersity, as determined by the ratio of weight-average molecular weight (Mw) to number-average molecular weight (Mn). Polymers having an Mw / Mn of less than 2.2, preferably less than 2.0, are most desirable. Suitable polyisobutylene substituents have polydispersity of about 1.5 to 2.1, or about 1.6 to about 1.8.

[0089] The dicarboxylic acid or anhydride can be selected from carboxylic acid reactants containing the corresponding acid halides and C1-C4 aliphatic esters, such as maleic anhydride, maleic acid, fumaric acid, malic acid, tartaric acid, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride, mesaconic acid, ethyl maleic acid, anhydride, dimethyl maleic anhydride, ethyl maleic acid, dimethyl maleic acid, and hexyl maleic acid. The molar ratio of the dicarboxylic acid or anhydride to the hydrocarbyl moiety in the reaction mixture used to produce hydrocarbyl dicarboxylic acid or anhydride may vary considerably. Therefore, the molar ratio can vary from 5:1 to 1:5, for example, from 3:1 to 1:3. A molar ratio of acid or anhydride to hydrocarbyl moiety of 1:1 to less than 1.6:1 is particularly preferred. Other useful molar ratios of dicarboxylic acid or anhydride to the hydrocarbyl moiety are 1.3:1–1.7:1, or 1.3:1–1.6:1, or 1.3:1–1.5:1.

[0090] Any of the numerous polyalkylene polyamines can be used in the preparation of dispersant additives. Non-limiting exemplary polyamines include aminoguanidine bicarbonate (AGBC), diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), pentaethylenehexamine (PEHA), and heavy polyamines. Heavy polyamines may include mixtures of polyalkylene polyamines that have small amounts of polyamine oligomers, such as TEPA and PEHA, but primarily have oligomers with seven or more nitrogen atoms and two or more primary amines per molecule, and have a broader branching range than conventional polyamine mixtures. Generally, these heavy polyamines have an average of 6.5 nitrogen atoms per molecule. Additional non-limiting polyamines that may be used to prepare hydrocarbyl-substituted succinimide dispersants are disclosed in U.S. Patent No. 6,548,458, the entire disclosure of which is incorporated herein by reference. The molar ratio of hydrocarbyl dicarboxylic acid or anhydride to polyalkylene polyamine may be approximately 1:1 to approximately 3.0:1.

[0091] Mannich base dispersants are typically reaction products of alkylphenols having long-chain alkyl substituents on the ring and one or more aliphatic aldehydes (particularly formaldehyde and its derivatives) containing about 1 to about 7 carbon atoms, and may also be polyamines (particularly polyalkylene polyamines). For example, a Mannich base ashless dispersant can be formed by condensing about 1 mole of long-chain hydrocarbon-substituted phenol with about 1 to about 2.5 moles of formaldehyde and about 0.5 to about 2 moles of polyalkylene polyamine.

[0092] The additional dispersants described herein may be borated and / or phosphorylated. These dispersants are generally reaction products of i) at least one phosphorus compound and / or boron compound and ii) at least one ashless dispersant.

[0093] Suitable boron compounds useful for forming dispersants in this specification include any boron compound or mixture of boron compounds that can introduce a boron-containing species into an ashless dispersant. Any organic or inorganic boron compound capable of undergoing such a reaction can be used. Thus, HBF4 boric acid (e.g., alkyl-B(OH)2, or aryl-B(OH)2), such as boron oxide, boron oxide hydrate, boron trifluoride, boron tribromide, boron trichloride, boric acid (i.e., H3BO3), tetraboric acid (i.e., H2B5O7), metaboric acid (i.e., HBO2), ammonium salts of such boric acid, and esters of such boric acid can be used. The use of complexes of boron trihalides with ethers, organic acids, inorganic acids, or hydrocarbons is a convenient means of introducing boron reactants into the reaction mixture. Such complexes are known and are exemplified by boron trifluoride-diethyl ether, boron trifluoride-phenol, boron trifluoride-phosphate, boron trichloride-chloroacetic acid, boron tribromide-dioxane, and boron trifluoride-methyl ethyl ether.

[0094] Suitable phosphorus compounds for forming dispersants in this specification include phosphorus compounds or mixtures of phosphorus compounds that can introduce phosphorus-containing species into the ashless dispersant. Therefore, either organic or inorganic phosphorus compounds capable of such reactions can be used. Accordingly, such inorganic phosphorus compounds can be used as inorganic phosphoric acid and inorganic phosphorus oxides, including its hydrates. Typical organophosphorus compounds include complete and partial esters of phosphoric acid, such as mono, di, and triesters of phosphoric acid, thiophosphate, dithiophosphate, trithiophosphate, and tetrathiophosphate; mono, di, and triesters of phosphoric acid, thiophosphate, dithiophosphate, and trithiophosphate; trihydrocarbyl phosphine oxide, trihydrocarbyl phosphine sulfide; mono and dihydrocarbyl phosphonates (RPO(OR′)(OR″), where R and R′ are hydrocarbyl and R″ is a hydrogen atom or a hydrocarbyl group); as well as their mono, di, and trithio analogs; mono and dihydrocarbyl phosphonates (RP(OR′)(OR″), where R and R′ are hydrocarbyl and R″ is a hydrogen atom or a hydrocarbyl group); as well as their mono and dithio analogs. Therefore, such compounds include, for example, phosphorous acid (H3PO3, sometimes represented as H2(HPO3), and sometimes called ortho-phosphorous acid or phosphonic acid), phosphoric acid (H3PO4, sometimes called ortho-phosphoric acid), subphosphoric acid (H4P2O6), metaphosphoric acid (HPO3), pyrophosphoric acid (H4P2O7), subphosphorous acid (H3PO2, sometimes called phosphinic acid), pyrosulfite (H4P2O5, sometimes called pyrophosphonic acid), phosphinic acid (H3PO), and tripolyphosphate (H5P3O 10 ), tetrapolyphosphate (H5P4O 13 It can be used as phosphorus trioxide, phosphorus tetraoxide, phosphorus pentoxide, etc. Phosphorotetrathioic acid (H3PS4), phosphoromonothioic acid (H3PO3S), phosphorodioic acid (H3PO2S2), phosphorotrithioic acid (H3POS3), phosphorus sesquisulfide, phosphorus heptasulfide, and phosphorus pentasulfide (P2S5, P4S 10Partial or whole sulfur analogs such as (sometimes referred to as) can also be used to form dispersants for the present disclosure. Inorganic phosphorus halogens such as PCl3, PBr3, POCl3, and PSCl3 can also be used.

[0095] Similarly, organophosphorus compounds such as mono, di, and triesters of phosphoric acid (e.g., trihydrocarbyl phosphate, dihydrocarbyl monoacid phosphate, monohydrocarbyl diacid phosphate, and mixtures thereof), mono, di, and triesters can be used; phosphorous acid (e.g., trihydrocarbyl phosphite, dihydrocarbyl hydrogen phosphite, hydrocarbyl diacid phosphite, and mixtures thereof); and esters of phosphonic acids (both "primary," RP(O)(OR)2, and "secondary"). The whole-sulfur or partially-sulfur analogs of any of the aforementioned organophosphorus compounds, such as R2P(O)(OR)), esters of phosphinic acids, phosphonyl halides (e.g., RP(O)Cl2 and R2P(O)Cl), halophosphates (e.g., (RO)PCl2 and (RO)2PCl), halophosphates (e.g., ROP(O)Cl2 and (RO)2P(O)Cl), tertiary pyrophosphate esters (e.g., (RO)2P(O)-OP(O)(OR)2), and all-sulfur or partially-sulfur analogs of any of the aforementioned organophosphorus compounds, wherein each hydrocarbyl group contains up to about 100 carbon atoms, preferably up to about 50 carbon atoms, more preferably up to about 24 carbon atoms, all or partially-sulfur analogs of any of the aforementioned organophosphorus compounds, and most preferably up to about 12 carbon atoms. Haloidal halophosphines (e.g., tetrahalohydrocarbyl phosphate, trihalodihydrocarbyl phosphate, and dihalotrihydrocarbyl phosphate) and halophosphines (monohalophosphines and dihalophosphines) can also be used.

[0096] The lubricants of this specification may include a mixture of one or more of the above-mentioned boronating and phosphorylated dispersants in combination with non-boronating and non-phosphorylating dispersants.

[0097] When used, the dispersant rate described above is provided at approximately 1 to 15 weight percent in the lubricant, approximately 2 to 13 weight percent in other approaches, and approximately 4 to 10 weight percent in other approaches.

[0098] Defoaming agents: Defoaming agents used to reduce or prevent the formation of stable foam include silicones, polyacrylates, or organic polymers. Foam inhibitors that may be useful in the compositions of the present invention include polysiloxanes, copolymers of ethyl acrylate and 2-ethylhexyl acrylate, and optionally vinyl acetate. If present, the amount of defoaming agent in the lubricating fluid may be up to 0.1% by weight, up to 0.08% by weight, or less than 0.07% by weight, based on the total weight of the lubricating fluid.

[0099] Seal swelling agents: The fluids of this disclosure may further contain seal swelling agents. Seal swelling agents such as esters, adipates, sebacates, azelates, phthalates, sulfones, alcohols, alkylbenzenes, substituted sulfolanes, aromatics, or mineral oils cause expansion of elastomer materials used as seals in engines and automatic transmissions.

[0100] Alcohol-based seal swelling agents are generally low-volatility linear alkyl alcohols such as decyl alcohol, tridecyl alcohol, and tetradecyl alcohol. Examples of alkylbenzenes useful as seal swelling agents include dodecylbenzene, tetradecylbenzene, dinonylbenzene, and di(2-ethylhexyl)benzene. Substituted sulfolanes (e.g., those described in U.S. Patent No. 4,029,588, incorporated herein by reference) are also useful as seal swelling agents in the compositions according to the present invention. Mineral oils useful as seal swelling agents in this disclosure include low-viscosity mineral oils having a high naphthene or aromatic content.

[0101] Generally speaking, the lubricating fluids described herein may contain additive components within the range listed in Table 2.

[0102] [Table 2]

[0103] The proportions of each component listed above represent the weight percentage of each component based on the total weight of the lubricating fluid containing the listed components. The additives used in the formulation of the compositions described herein may be mixed with the base oil individually or in various subcombinations. However, it may be preferable to mix all the components simultaneously using an additive concentrate (i.e., the additive plus a diluent such as a hydrocarbon solvent). The use of an additive concentrate takes advantage of the intercompatibility provided by the combination of components when they are in the form of an additive concentrate. Furthermore, the use of a concentrate reduces mixing time and the possibility of mixing errors. [Examples]

[0104] The following non-limiting embodiments are provided to further illustrate the features and advantages of one or more embodiments of the present disclosure. Unless otherwise noted or evident from the context of the discussion, all percentages, ratios and parts described in the embodiments and elsewhere of the present disclosure are by weight.

[0105] The high volume resistivity of electric motor transmission fluids, and therefore their ability to function as insulators to some extent, is beneficial. A higher resistivity score indicates the fluid's ability to act as an insulator. To demonstrate how a phosphated succinimide dispersant containing 2.0 wt% to 3.5 wt% phosphorus increases the resistivity of fluids, exemplary finished fluids were formulated, aged, and evaluated.

[0106] To age the fluids, the fluids were accelerated by using the Indiana stirred oxidation test (a modified version of JIS K2514-1) at 150°C. The resistivity of the oxidized fluids was measured after the fluids had cooled to 30°C. The resistivity of the fluids was measured at 30°C using an Epsilon+ electrical conductivity meter (Flucon Fluid Control GmbH) or an equivalent 1.5-volt meter, according to a modified version of ASTM D2624-15 (test for lubricants, not fuels), and at least one reading was obtained for each fluid being evaluated.

[0107] The fluids were also evaluated for their abrasion performance and corrosion compatibility with copper. The abrasion performance of the fluids was measured according to ASTM D4172. Corrosion compatibility with copper was measured using an extended copper corrosion test (a modified version of ASTM D130-18), in which copper strips were immersed in the lubricant for a set time and at a specified temperature. The oils were evaluated for their copper levels. A high copper level in the oil indicates the corrosiveness of the lubricant to copper. In the following example, the temperature was maintained at 150°C for 120 hours.

[0108] All formulations tested in Table 3 below contained the same basic additive package, including friction modifiers, corrosion inhibitors, cleaning agents, antioxidants, borooxide and phosphorylation dispersants, and copper corrosion inhibitors. The formulations also contained a phosphorus source. The formulations of the present invention contained the phosphorylated succinimide dispersant described herein, while the comparative formulations contained other types of phosphorus-containing compounds. Details of these components are described below. The formulations were tested with a wide range of base oils at kinematic viscosities of 4.10–4.33 cSt at 100°C.

[0109] Phosphorus source A: A phosphorylated succinimide dispersant made from a mixture of HR-polyisobutylene with Mn of 975-1175, maleic anhydride, polyalkylene polyamines with an average of 6.5 nitrogen atoms per molecule, and phosphoric acid. The dispersant was a reaction product of succinimide and phosphorus. This dispersant contains approximately 3.0% by weight of phosphorus and approximately 1.4% by weight of nitrogen.

[0110] Phosphorus source B: A phosphorylated and borodic succinimide dispersant made from a mixture of conventional polyisobutylene with Mn of 900-980, maleic anhydride, polyalkylene polyamines with an average of 6.5 nitrogen atoms per molecule, phosphoric acid, and boric acid. This dispersant contains approximately 0.76% by weight of phosphorus, approximately 0.35% by weight of boron, and approximately 1.75% of nitrogen.

[0111] Phosphorus source C: This phosphorus source is obtained by salting the reaction product of sulfur and dibutyl hydrogen phosphonate with an amine. This phosphorus source contains approximately 6 wt% phosphorus, approximately 6.3 wt% sulfur, and approximately 3.1 wt% nitrogen.

[0112] Phosphorus source D: An alkylthiophosphate ester containing approximately 9 wt% phosphorus and approximately 19 wt% sulfur.

[0113] The formulation of the present invention, containing phosphorus source A, a highly phosphorylated succinimide dispersant, achieved remarkably improved lubricant resistance. Furthermore, the formulation of the present invention, containing phosphorus source A, also achieved favorable copper corrosion compatibility and wear performance.

[0114] [Table 3]

[0115] Table 3 shows that Inv.1, Comp.1, Comp.2, and Comp.3 were formulated to have nearly the same kinematic viscosity. Each formulation contained a different phosphorus source but had a similar phosphorus treatment rate. Inv.1, containing phosphorus source A, had a higher resistivity after aging compared to the corresponding Comp.1, 2, and 3. Inv.1 also maintained favorable wear performance and copper corrosion compatibility. Comp.1, containing phosphorus source B, had slightly fewer wear marks than Inv.1, but due to the higher copper content in the oil, it had a lower ability to suppress copper corrosion and a lower electrical resistivity after aging. Comp.3, containing phosphorus source D, showed slightly better copper corrosion performance than Inv.1, but had larger wear marks and lower electrical resistivity. Comp.2 performed worse than Inv.1 in terms of wear, copper corrosion compatibility, and electrical resistivity.

[0116] Inv.2 and Comp.4 were formulated to have nearly the same kinematic viscosity. Although each formulation contained a different phosphorus source, they had similar phosphorus treatment rates. Inv.2, containing phosphorus source A, had higher resistivity and superior copper corrosion compatibility and wear performance compared to Comp.4.

[0117] Inv.3-Inv.5 and Comp.5 and 6 are additional examples of the fluids of the present invention and comparative fluids formulated with various kinematic viscosities and phosphorus treatment rates, as shown in Table 4 below. Comparative samples 5 and 6 used phosphorus source A and may have shown less wear marks and copper corrosion, but both are considered to have low resistivity, partly due to the contribution of the base oil.

[0118] [Table 4]

[0119] The lubricating compositions of this disclosure are described in detail and in the summary herein, but the foregoing description should be understood to describe, and not limit, the scope of this disclosure as defined by the appended claims. Other aspects, advantages, and modifications are within the claims. This specification and examples are for illustrative purposes only, and the true scope of this disclosure is intended to be shown by the appended claims.

[0120] Other embodiments of this disclosure will become apparent to those skilled in the art from consideration of this specification and the practice of the embodiments disclosed herein. Where used throughout the specification and claims, “a” and / or “an” may refer to one or more. Unless otherwise indicated, all figures representing properties such as amounts, molecular weights, percentages, ratios, and reaction conditions of components used herein should be understood in all cases as being modified by the term “approximately,” whether or not the term “approximately” is present. Thus, unless otherwise indicated, the numerical parameters described herein are approximations that may vary depending on the desired properties to be obtained by this disclosure. At the very least, each numerical parameter should be interpreted by applying ordinary rounding techniques, taking into account the reported number of significant figures, and not as an attempt to limit the application of the doctrine of equivalents to the claims. Although the numerical ranges and parameters describing the broad disclosure are approximations, the numerical values ​​described in specific embodiments are reported as accurately as possible. However, any numerical value inherently contains a certain error that inevitably arises from the standard deviation found in their respective test measurements.

[0121] It should be understood that each component, compound, substituent, or parameter disclosed herein is disclosed for use alone or in combination with any one or more other components, compounds, substituents, or parameters disclosed herein.

[0122] It should be further understood that each range disclosed herein should be interpreted as a disclosure of each specific value within the disclosure range having the same number of significant figures. Thus, the range 1–4 should be interpreted as a clear disclosure of the values ​​1, 2, 3, and 4, as well as any range of values ​​such as 1–4, 1–3, 1–2, 2–4, 2–3, etc.

[0123] It should be further understood that each lower limit of each range disclosed herein should be interpreted as being disclosed in combination with each upper limit of each range and each specific value within each range disclosed herein for the same component, compound, substituent, or parameter. Therefore, this disclosure should be interpreted as a disclosure of all ranges derived by combining each lower limit of each range with each upper limit of each range, or with each specific value within each range, or by combining each upper limit of each range with each specific value within each range.

[0124] Furthermore, any specific amounts / values ​​of components, compounds, substituents, or parameters disclosed in the description or examples should be interpreted as disclosures of either a lower or upper limit of a range, and thus, in combination with any other lower or upper limit of ranges or specific amounts / values ​​for the same component, compound, substituent, or parameter disclosed elsewhere in this application, can form a range for that component, compound, substituent, or parameter.

Claims

1. A lubricating composition for use in electric vehicles, A lubricating base oil composition comprising at least 95 weight percent of a base oil of API Group III, or a base oil selected from a blend of a Group III base oil and a Group II base oil, a Group V base oil, or a mixture thereof. A phosphorylated succinimide dispersant containing 2% to 3.5% by weight of phosphorus, comprising a phosphorylated succinimide dispersant that provides 100 to 650 ppm of phosphorus to the lubricating composition, The lubricating composition has 700 ppm or less of total phosphorus, and the phosphorylated succinimide dispersant provides at least 70% of the total phosphorus. The lubricating composition has a kinematic viscosity of 3 cSt to 6.5 cSt at 100°C, and after aging the lubricating composition at 150°C according to JIS K2514-1, it has a resistivity of at least 50 MΩ·m when measured at 1.5 volts and 30°C according to ASTM D2624-15. If the lubricating base oil composition contains a base oil of API group V, the base oil of API group V is present in an amount of up to 15% by weight based on the total lubricating composition. The lubricating base oil composition, if it contains an API group II base oil, is present in an amount of up to 80% by weight based on the total lubricating composition.

2. The lubricating composition according to claim 1, wherein the phosphorylated succinimide dispersant is a first dispersant, and the composition further comprises a second dispersant containing 0.2% to 0.4% by weight of phosphorus, wherein the second dispersant provides the lubricating composition with 50 ppm or less of phosphorus.

3. The lubricating composition according to claim 1, wherein the phosphorylated succinimide dispersant contains 2.5% to 3.0% by weight of phosphorus, and / or the phosphorylated succinimide dispersant provides 115 ppm to 600 ppm of phosphorus to the lubricating composition, and / or the phosphorylated succinimide dispersant provides 115 ppm to 250 ppm of phosphorus to the lubricating composition, and / or the phosphorylated succinimide dispersant provides 250 ppm or less of phosphorus to the lubricating composition, and the lubricating composition has a total phosphorus of 300 ppm or less.

4. The lubricating composition according to claim 2, wherein the first dispersant delivers 115 ppm to 250 ppm of phosphorus to the lubricating composition, and the second dispersant delivers 40 ppm or less of phosphorus to the lubricating composition.

5. The lubricating composition according to claim 1, wherein after the lubricating composition is aged at 150°C in accordance with JIS K2514-1, the lubricating composition has a resistivity of at least 115 MΩ·m.

6. The lubricating composition according to claim 1, wherein the base oil composition is selected from an API Group III base oil or a mixture of an API Group II base oil and an API Group III base oil.

7. The lubricating composition according to claim 6, wherein the phosphorylated succinimide dispersant provides 115 ppm to 250 ppm of phosphorus to the lubricating composition, and / or the lubricating composition has 160 ppm to 300 ppm of total phosphorus, a kinematic viscosity of 5.5 cSt to 6.0 cSt at 100°C, and a resistivity of at least 115 MΩ·m after the lubricating composition has been aged at 150°C according to JIS K2514-1.

8. A method for improving the electrical resistivity of a lubricating composition for an electric vehicle, wherein the composition is applied to the powertrain of an electric vehicle. A lubricating base oil composition comprising at least 95 weight percent of a base oil of API Group III, or a base oil selected from a blend of an API Group III base oil and an API Group II base oil, an API Group V base oil, or a mixture thereof. The present invention provides a lubricating oil comprising a composition containing a phosphorylated succinimide dispersant containing 2% to 3.5% by weight of phosphorus, which provides 100 to 650 ppm of phosphorus to the lubricating composition. The lubricating composition has 700 ppm or less of phosphorus, and the phosphorylated succinimide dispersant provides at least 70% of the total phosphorus. The lubricating oil has a kinematic viscosity of 3 cSt to 6.5 cSt at 100°C, and after the lubricating composition is aged at 150°C according to JIS K2514-1, it has a resistivity of at least 50 MΩ·m when measured at 1.5 volts and 30°C using the lubricating composition according to ASTM D2624-15. If the lubricating base oil composition contains a base oil of API group V, the base oil of API group V is present in an amount of up to 15% by weight based on the total lubricating composition. A method wherein, if the lubricating base oil composition contains an API group II base oil, the API group II base oil is present in an amount of up to 80% by weight based on the total lubricating composition.

9. The method according to claim 8, wherein the phosphorylated succinimide dispersant is a first dispersant, and the composition further comprises a second dispersant containing 0.2% to 0.4% by weight of phosphorus, wherein the second dispersant provides the lubricating composition with 50 ppm or less of phosphorus.

10. The method according to claim 8, wherein the phosphorylated succinimide dispersant contains 2.5% to 3.0% by weight of phosphorus, and / or the phosphorylated succinimide dispersant provides 115 ppm to 600 ppm of phosphorus to the lubricating composition, and / or the phosphorylated succinimide dispersant provides 115 ppm to 250 ppm of phosphorus to the lubricating composition.

11. The method according to claim 9, wherein the first dispersant delivers 115 ppm to 250 ppm of phosphorus to the lubricating composition, and the second dispersant delivers 40 ppm or less of phosphorus to the lubricating composition.

12. The method according to claim 8, wherein the phosphorylated succinimide dispersant provides 250 ppm or less of phosphorus to the lubricating composition, and the lubricating composition has 300 ppm or less of total phosphorus.

13. The method according to claim 8, wherein the lubricating composition has a resistivity of at least 115 MΩ·m after being aged at 150°C in accordance with JIS K2514-1.

14. The method according to claim 8, wherein the base oil composition is selected from a base oil of API group III or a blend of base oils of API group II and III or a mixture thereof.

15. The method according to claim 14, wherein the phosphorylated succinimide dispersant provides 115 ppm to 250 ppm of phosphorus to the lubricating composition, and after the lubricating composition is aged at 150°C according to JIS K2514-1, the lubricating composition has 160 ppm to 300 ppm of total phosphorus, a kinematic viscosity of 5.5 cSt to 6.0 cSt at 100°C, and a resistivity of at least 115 MΩ·m.

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