High-performance gear oil and related methods

Abstract

A gear oil composition comprising a first oil base stock and a second base stock. The first base stock is 250 mm 2 / sec~600mm 2 Kinematic viscosity in 1 / second (ASTM D445, 40°C), 20 mm 2 / sec~70mm 2 The bright stocks of Group II have a kinematic viscosity of 1 / second (ASTM D445, 100°C), a viscosity index of 80-120 (ASTM D2270), and a pour point of -50°C--20°C (ASTM D97). The second base stock is 500 mm 2 / sec~3500mm 2 Kinematic viscosity in 60 mm² / second (ASTM D445, 40°C), 60 mm 2 / sec~300mm 2 It contains a polyalphaolefin (PAO) base stock having a kinematic viscosity of 1 / second (ASTM D445, 100°C), a viscosity index of 150-250 (ASTM D2270), and a pour point of -50°C to -20°C (ASTM D97).

Description

[Technical Field]

[0001] This application relates to a composition suitable for use as a lubricant, more specifically for use as a gear oil, and to a related method. [Background technology]

[0002] Oil base stock is a major component of finished lubricants and significantly contributes to their properties. Gear oil is a finished lubricant used in automotive, industrial, or marine industries, such as gearboxes, transmissions, differentials, transaxles, and transfer cases. Gear oil helps to ensure smooth operation of the drivetrain and protects critical internal components of the vehicle's various gear systems from damage caused by heat and wear. Insufficient lubrication can cause pitting (e.g., micropitting), corrosion, scouring, scuffing, and other damage to drivetrain components. Gear oil generally has a higher viscosity compared to other similar lubricants, such as engine oil. The high viscosity of gear oil allows it to handle rotational, sliding, or other frictional motions between parts of machinery and equipment. Gear oil typically contains two main components: one or more oil-based stocks and additives. Blends of these components can be used to achieve specific desired characteristics of the gear oil.

[0003] According to the American Petroleum Institute (API) classification, oil-based stocks are classified into five groups based on saturated hydrocarbon content, sulfur levels, and viscosity index. Lubricating oil-based stocks are typically produced on a large scale from non-renewable petroleum sources. Groups I, II, and III oil-based stocks are produced from crude oil through a wide range of processes, including solvent extraction, dewaxing with solvents or catalysts, and hydroisomerization. Group III oil-based stocks can also be produced from synthetic hydrocarbon liquids obtained from natural gas, coal, or other fossil resources. Group IV base stocks are polyalphaolefins (PAOs), produced by oligomerization of alphaolefins such as propene, 1-butene, or 1-decene. Group V base stocks include all base stocks not belonging to Groups I-IV, such as naphthenic compounds, polyalkylene glycols (PAGs), and esters. Historically, gear oil formulations have been limited to the use of API Group I oil-based stocks, particularly Group I bright stocks, polyisobutylene, conventional polyalphaolefins (PAOs), and metallocene PAOs, achieving sufficiently high viscosity for gear oil applications. High-performance gear oils are designed for extreme friction protection, such as that which occurs under high-speed, high-load, high-torque, and high-horsepower conditions, as well as protection from extreme temperatures, shock loads, scuffing, scowling, and pitting. Generally, oil-based stocks for high-performance gear oil formulations are limited to conventional PAOs, metallocene PAOs, API Group V oil-based stocks, or mixtures of these three. Conventional gear oils, especially high-performance gear oils, can be very expensive given their heavy reliance on synthetic oils. Therefore, there is a need for low-cost gear oils, particularly those that can meet required industry standards and regulations and be used in high-performance applications. [Overview of the project]

[0004] The various details of the present disclosure are summarized below to provide a basic understanding. This summary is not an exhaustive overview of the present disclosure, nor is it intended to identify certain elements of the present disclosure or to detail its scope. Rather, the primary purpose of this summary is to present some concepts of the present disclosure in a simplified form prior to the more detailed description presented later. The first non-limiting gear oil composition of the present disclosure has a kinematic viscosity (ASTM D445, 40 °C) of 250 mm 2 / s to 600 mm 2 / s, a kinematic viscosity (ASTM D445, 100 °C) of 20 mm 2 / s to 70 mm 2 / s, a viscosity index (ASTM D2270) of 80 to 120, and a pour point (ASTM D97) of -50 °C to -20 °C, and a first oil base stock which is a Group II bright stock, and 500 mm 2 / s to 3500 mm 2 / s, a kinematic viscosity (ASTM D445, 100 °C) of 60 mm 2 / s to 300 mm 2 / s, a viscosity index (ASTM D2270) of 150 to 250, and a pour point (ASTM D97) of -50 °C to -20 °C, and a second oil base stock which is a polyalphaolefin (PAO) base stock, and includes a gear oil composition.

[0005] The second non-limiting method of a gear oil of the present disclosure includes the step of mixing a first oil base stock and a second base stock, the first base stock having a kinematic viscosity (ASTM D445, 40 °C) of 250 mm 2 / s to 600 mm 2 / s, a kinematic viscosity (ASTM D445, 〈0000011〉100 °C) of 20 mm 2 / s to 70 mm 2 / s, a viscosity index (ASTM D2270) of 80 to 120, and a pour point (ASTM D97) of -50 °C to -20 °C, and being a Group II bright stock, the second base stock having a kinematic viscosity (ASTM D445, 40 °C〉 of 500 mm 2 / s to 3500 mm 2Kinematic viscosity in 60 mm² / second (ASTM D445, 40°C), 60 mm 2 / sec~300mm 2 This is a polyalphaolefin (PAO)-based stock having a kinematic viscosity of 1 / second (ASTM D445, 100°C), a viscosity index of 150-250 (ASTM D2270), and a pour point of -50°C to -20°C (ASTM D97). The compositions and methods disclosed herein, as well as these and other characteristics and attributes of their advantageous uses and / or applications, will become apparent from the following detailed description. [Modes for carrying out the invention]

[0006] This application relates to a composition suitable for use as a lubricant, more specifically for use as a gear oil, and to a related method. This disclosure provides gear oil compositions comprising at least a bright stock (BS) of Group II, a PAO base stock, and possibly a low viscosity (LS) trim oil base stock of Groups II-IV, and possibly an auxiliary base stock of Group V. The gear oil compositions described herein perform advantageously at the same level as more expensive pure conventional PAO formulations and other synthetic gear oils and can be used in automotive, industrial, and marine applications. Accordingly, the gear oils described herein offer significant advantages in this area without compromising performance.

[0007] The gear oils of this disclosure may further improve the elastofluid lubrication (EHL) film thickness (resulting in a thicker EHL film), and therefore may significantly improve gear life and pitting (e.g., micropitting) performance compared to conventional gear oil formulations (e.g., conventional PAO-based gear oils). Unexpectedly, the gear oils of this disclosure further achieve the required industry standards and regulations and the advantages listed above without sacrificing oxidation performance or cleanliness. Furthermore, unexpectedly, the gear oils described exhibit comparable viscosity index (VI) and low-temperature characteristics to conventional PAO gear oils, which had not been previously achieved with base oils other than Group IV and Group V. As described above, the gear oil compositions of this disclosure can be used in automotive, industrial, and marine applications. In certain embodiments, the gear oil is specifically formulated for lubricating gearboxes, transmissions, differentials, transaxles, and transfer cases. For example, in one embodiment, the gear oil is formulated for lubricating the gearbox (e.g., main gearbox) of a wind turbine.

[0008] definition As used herein, “mass%” refers to a percentage by mass, “volume%” refers to a percentage by volume, “mol%” refers to a percentage by mole, “ppm” refers to parts per million, and “ppm wt” and “wppm” are interchangeable and mean parts per million on a mass basis. All concentrations as used herein are expressed on a total basis of the composition in question unless otherwise indicated. As used herein, the terms “oil base stock,” “oil basestock,” “base oil,” “base stock,” or “bright stock,” and their grammatical variations thereof, refer to any base fluid that can be used in lubricating oils, including but not limited to terpenes, mineral oils, synthetic hydrocarbons, esters, or any combination thereof. The oil base stocks described herein may refer to base oils of Groups I, II, III, IV, and V (as defined by the American Petroleum Institute (API)), and any combination thereof.

[0009] Base stock blend This disclosure includes methods and compositions relating to gear oils comprising at least API Group II bright stocks and PAO. Optionally, the gear oil may also comprise trim oil base stocks of Groups II-IV. Furthermore, optionally, the gear oil may also comprise auxiliary base stocks of Group V. Group II bright stocks are formed from Group II base stocks, for example, through catalytic treatment of delaminated Group II base stocks, or through hydrogenation (acidic conditions) and subsequent catalytic dewaxing (sweet conditions) of delaminated Group II oils. Because the gear oil formulations of this disclosure use ultra-heavy Group II bright stocks, they can achieve performance improvements similar to or exceeding the performance standards of gear oils formulated solely with Group IV base stocks (e.g., PAO), while being more cost-effective and eliminating the need to increase the mass percentage of thickeners. Examples of suitable commercially available Group II bright stocks include, but are not limited to, EHC 340 MAX® (ExxonMobil, Texas).

[0010] Suitable Group II bright stocks are 250mm 2 / sec~600mm 2 / second (or 250mm) 2 / sec~300mm 2 / second, or 320mm 2 / sec~520mm 2 / sec, or 380mm 2 / sec~520mm 2 / sec, or 450mm 2 / sec~520mm 2 / sec, or 288mm 2 / sec~352mm 2 The kinematic viscosity (ASTM D445-21, 40°C), encompassing any value and subset therein, and 20 mm 2 / sec~70mm 2 / second (or 20mm) 2 / sec~36mm 2 / sec, or 27mm 2 / sec~36mm 2 / sec, or 36mm 2 / sec ~ 42mm 2 / sec, or 45mm 2 / sec~50mm 2 / second, or 60mm 2 / sec~70mm 2The kinematic viscosity (ASTM D445-21, 100°C) may have a flow rate ( / sec), and encompass any value and subset in between. Suitable brightstocks of group II may have a viscosity index (ASTM D2270-16) of 80 to 120 (or 95 to 115, or 100 to 110, or 105 to 110), and encompass any value and subset in between. Suitable brightstocks of group II may have a pour point (IP15 or ASTM D97) of -50°C to -20°C (or -45°C to -30°C, or -45°C to -39°C), and encompass any value and subset in between.

[0011] The gear oils of this disclosure further comprise PAO or ETL (ethylene-to-liquid), which are not considered to be particularly limiting. PAO may include, for example, conventional PAO (light or heavy), metallocene PAO (mPAO), and any combination thereof. In some embodiments, the PAO is mPAO or a combination of mPAOs, and suitable examples of mPAOs include, but are not limited to, mPAO300, mPAO150, mPAO65, and any combination thereof.

[0012] In one or more examples, the PAO used in the gear oil of this disclosure is 500 mm 2 / sec~3500mm 2 / second (or 500mm) 2 / sec~1000mm 2 / second, or 1000mm 2 / sec~1500mm 2 / second, or 1500mm 2 / sec~2000mm 2 / second, or 2000mm 2 / sec~2500mm 2 / second, or 2500mm 2 / sec~3000mm 2 / second, or 3000mm 2 / sec~3500mm 2 / second, or 1000mm 2 / sec~2500mm 2kinematic viscosity (ASTM D445, 40°C), encompassing any value and subset therein, and 60 mm 2 / sec~300mm 2 / second (or 60mm) 2 / sec~100mm 2 / second, or 100mm 2 / sec~150mm 2 / second, or 150mm 2 / sec~200mm 2 / second, or 200mm 2 / sec~250mm 2 / second, or 250mm 2 / sec~300mm 2 / second, or 100mm 2 / sec~250mm 2 The PAO may have a kinematic viscosity (ASTM D445-21, 100°C) encompassing any value and subset between 150°C and 250°C (or 150°C and 165°C, or 170°C and 200°C, or 175°C and 180°C, or 200°C and 250°C, or 170°C and 250°C). The PAO may have a pour point (IP15 or ASTM D97) encompassing any value and subset between 50°C and 20°C (or -45°C and 30°C, or -45°C and 39°C).

[0013] In some embodiments, the bright stock of Group II may be present in the gear oil in amounts of 15% to 50% by mass (or 15% to 30% by mass, or 25% to 35% by mass, or 30% to 35% by mass, or 40% to 45% by mass, or 45% to 50% by mass) relative to the total mass of the gear oil formulation, as well as encompassing any values ​​and subsets in between. In certain preferred embodiments, the PAO may be metallocene PAO. Regardless of the type of PAO, the PAO may be present in the gear oil in amounts encompassing 10% to 70% by mass (or 25% to 50% by mass, or 45% to 50% by mass, or 50% to 60% by mass, or 55% to 65% by mass, or 60% to 70% by mass) relative to the total mass of the gear oil formulation, as well as any value and subsets in between.

[0014] As stated above, the gear oil may further contain Group II–IV trim oil base stocks as needed. “Trim oil base stock” and its grammatical variations refer to low viscosity (LS) oil base stocks used to make any necessary adjustments to the gear oil blend to ensure that the gear oil meets the requirements as a gear oil lubricant, based on desired formulation requirements and industry standards and regulations. Suitable LS trim oil base stocks may include, but are not limited to, any LS Group II–IV oil base stocks, including, but not limited to, PAO (e.g., PAO6, PAO4), gas-to-liquid (GTL) base stocks (e.g., GTL4, GTL8), and any combination thereof. Examples of commercially available trim oil base stocks suitable for use in this disclosure include, but are not limited to, EHC® base stocks (ExxonMobil, Texas), such as EHC® 50. If included, any LS trim oil base stock may be present in amounts of 3% to 35% by mass (or 3% to 5% by mass, or 5% to 7.5% by mass, or 7.5% to 10% by mass, or 10% to 12% by mass, or 12% to 18% by mass, or 18% to 20% by mass, or 20% to 25% by mass, or 25% to 32% by mass, or 32% to 35% by mass) relative to the total mass of the gear oil formulation, as well as amounts encompassing any values ​​and subsets in between.

[0015] As described above, the gear oil may further contain a Group V base stock containing, as required, naphthenic compounds, polyalkylene glycols (PAGs), esters (e.g., phosphate esters, polyesters), etc. Suitable Group V base stocks have a kinematic viscosity (ASTM D445, 40°C) of 15 mm 2 / s to 600 mm 2 / s (or 15 mm 2 / s to 100 mm 2 / s, or 200 mm 2 / s to 300 mm 2 / s, 320 mm 2 / s to 520 mm 2 / s, or 380 mm 2 / s to 520 mm 2 / s, or 450 mm 2 / s to 520 mm 2 / s), and include any value and subset therebetween, and a kinematic viscosity (ASTM D445-21, 100°C) of 4 mm 2 / s to 60 mm 2 / s (or 4 mm 2 / s to 15 mm 2 / s, or 20 mm 2 / s to 36 mm 2 / s, or 27 mm 2 / s to 36 mm 2 / s, or 36 mm 2 / s to 42 mm 2 / s, or 45 mm 2 / s to 50 mm 2 / s), and include any value and subset therebetween. Suitable Group V base stocks have a viscosity index (ASTM D2270-16) of 80 to 200 (or 95 to 115, or 100 to 120, or 120 to 140, or 140 to 160, or 160 to 180, or 180 to 200, or 100 to 200, or 150 to 200, or 80 to 150), and include any value and subset therebetween. Suitable Group II bright stocks have a pour point (IP15 or ASTM D97) of -60°C to -20°C (or -60°C to -50°C, or -45°C to -30°C, or -45°C to -39°C), and include any value and subset therebetween.

[0016] Overall, the bright stocks of Group II, PAO, and any base stocks of Group V may be present in the gear oil formulations of this disclosure in amounts of 60% to 99.5% by mass (or 70% to 99.5% by mass, or 80% to 99.5% by mass, or 60% to 95% by mass, or 70% to 95% by mass, or 80% to 95% by mass, or 80% to 94% by mass, or 80% to 93% by mass, or 85% to 95% by mass, or 85% to 94% by mass, or 85% to 93% by mass) and any values ​​and subsets in between, relative to the total mass of the gear oil formulation.

[0017] Solubilizer Solubilizing agent additives may include esters of dibasic acids (e.g., phthalic acid, succinic acid, alkyl succinic acid, alkenyl succinic acid, maleic acid, azelaic acid, suberic acid, sebacic acid, fumaric acid or adipic acid (adipate), or linoleic acid dimers (dimmers)) and alcohols (e.g., butyl, hexyl, 2-ethylhexyl, dodecyl alcohol, ethylene glycol, diethylene glycol monoether, or propylene glycol), esters of monocarboxylic acids with 5 to 18 carbon atoms and polyols (e.g., neopentyl glycol, trimethylolpropane (TMP), pentaerythritol, dipentaerythritol, or tripentaerythritol), naphthalene compounds (e.g., alkylated naphthalenes), and any combination thereof. Other compounds useful as solubilizers include polyoxyalkylene glycols, polyoxyalkylene glycol esters, polyoxyalkylene glycol ethers, and phosphate esters. In certain embodiments, the solubilizer is a TMP ester, an adipate ester, an alkylated naphthalene, or any combination thereof. The solubilizer may be incorporated in amounts of 2.5% to 20% by mass (or 2.5% to 3% by mass, or 3% to 5% by mass, or 5% to 10% by mass, or 15% to 20% by mass, or 20% to 25% by mass) relative to the total mass of the gear oil formulation, and encompassing any values ​​and subsets therein.

[0018] additives The gear oil formulations of this disclosure may contain one or more additives, including but not limited to ashless dispersants, pour point depressants, defoamers, antioxidants, rust inhibitors, friction modifiers, viscosity index improvers, and any combination thereof, in order to satisfy a variety of characteristics (e.g., those related to friction, oxidation stability, cleanliness, defoaming, viscosity, etc.). The ashless dispersants used in the gear oil formulations of this disclosure may include, but are not limited to, those based on polybutenyl succinimide, polybutenyl succinamide, benzylamine, succinate esters, succinate ester amides and their boron derivatives, and any combination thereof. Where included, the ashless dispersant may be contained in the gear oil formulation in amounts of 0.05% to 5% by mass (or 0.05% to 0.1% by mass, or 0.5% to 1% by mass, or 1% to 2% by mass, or 2% to 4% by mass, or 2.5% to 5% by mass) and any values ​​and subsets therein, based on the total mass of the gear oil formulation.

[0019] The pour point depressants used in the gear oil formulations of this disclosure may include, but are not limited to, ethylene / vinyl acetate copolymers, condensates of chlorinated paraffin and naphthalene, condensates of chlorinated paraffin and phenol, polymethacrylates, polyalkylstyrenes, and any combination thereof. Where included, the pour point depressant may be present in the gear oil formulation in amounts of 0.05% to 5% by mass (or 0.05% to 0.1% by mass, or 0.5% to 1% by mass, or 1% to 2% by mass, or 2% to 4% by mass, or 2.5% to 5% by mass) relative to the total mass of the gear oil formulation, as well as any values ​​and subsets therein. It should be further noted that the gear oil formulations of this disclosure may be formulated so that a pour point depressant is not required to maintain the pour point of the gear oil below -20°C. That is, the pour point of the gear oil will be maintained below or below -20°C if no pour point depressant is included.

[0020] The defoaming agents used in the gear oil formulations of the present invention may include, but are not limited to, dimethylpolysiloxane, polyacrylates and their fluorine derivatives, perfluoropolyethers, and any combination thereof. If included, the defoaming agent may be present in the gear oil formulation in amounts of 0.05% to 5% by mass (or 0.05% to 0.1% by mass, or 0.5% to 1% by mass, or 1% to 2% by mass, or 2% to 4% by mass, or 2.5% to 5% by mass) relative to the total mass of the gear oil formulation, as well as any values ​​and subsets therein.

[0021] The antioxidants used in the gear oil formulations of the present invention may include, but are not limited to, amine-based antioxidants (e.g., alkylated diphenylamine, phenyl-α-naphthylamine, and alkylated phenyl-x-naphthylamine), phenol-based antioxidants (e.g., 2,6-di-t-butylphenol, 4,4'-methylenebis-(2,6-di-t-butylphenol), and isooctyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate), sulfur-based antioxidants (e.g., dilauryl-3,3'-thiodipropionate), zinc dithiophosphate, and any combination thereof. If included, antioxidants may be present in the gear oil formulation in amounts of 0.05% to 5% by mass (or 0.05% to 0.1% by mass, or 0.5% to 1% by mass, or 1% to 2% by mass, or 2% to 4% by mass, or 2.5% to 5% by mass) relative to the total mass of the gear oil formulation, as well as any values ​​and subsets in between.

[0022] The rust inhibitors used in the gear oil formulations of the present invention may include, but are not limited to, fatty acids, alkenyl succinate half-esters, fatty acid soaps, alkyl sulfonates, polyhydric alcohols / fatty acid esters, fatty acid amines, oxidized paraffins, and alkyl polyoxyethylene ethers, as well as any combination thereof. If included, the rust inhibitor may be present in the gear oil formulation in amounts of 0.05% to 5% by mass (or 0.05% to 0.1% by mass, or 0.5% to 1% by mass, or 1% to 2% by mass, or 2% to 4% by mass, or 2.5% to 5% by mass) relative to the total mass of the gear oil formulation, as well as any values ​​and subsets therein.

[0023] The friction modifiers used in the gear oil formulations of the present invention may include, but are not limited to, organic molybdenum compounds, fatty acids, higher alcohols, fatty acid esters, oils / fat, amines, polyamides, sulfur esters, phosphate esters, acidic phosphate esters, acidic phosphate esters, amine salts of phosphate esters, and any combination thereof. If included, the friction modifier may be present in the gear oil formulation in amounts of 0.05% to 5% by mass (or 0.05% to 0.1% by mass, or 0.5% to 1% by mass, or 1% to 2% by mass, or 2% to 4% by mass, or 2.5% to 5% by mass) relative to the total mass of the gear oil formulation, as well as any values ​​and subsets therein. Viscosity index improvers used in the gear oil formulations of the present disclosure may include, but are not limited to, polyisobutylene, polymethacrylate, olefin copolymers (such as ethylene-propylene copolymers, ethylene-propylene-diene-modified copolymers (EPDM), etc.), hydrogenated styrene block copolymers (such as styrene-ethylene / butylene-styrene copolymers (SEBS), etc.), and any combination thereof. When included, the viscosity index improver is 0.05% to 5% by mass (or 0.05% to 0.1% by mass, or 0.5% to 1% by mass, or 1% to 2% by mass, or 2% to 4% by mass, or 2.5% to 5% by mass), and any value and subset therebetween, based on the total mass of the gear oil formulation, and may be included in the gear oil formulation. It should be further noted that the gear oil formulations of the present disclosure may be formulated such that a viscosity index improver is not required to maintain the viscosity index of the gear oil within the range described below (150 or more). That is, when the viscosity index improver is not included, the viscosity index of the gear oil is maintained at 150 or more.

[0024] Gear oil formulations The gear oil formulations of the present disclosure include at least bright stock of Group II, PAO base stock, any trim oil base stock of Groups II to IV, and any Group V auxiliary base stock. Further, the gear oil formulations may include a solubilizer and one or more additives. The gear oil formulation has a kinematic viscosity (ASTM D445-21, 40 °C) that may include 300 mm 2 / s to 600 mm 2 / s (or 320 mm 2 / s to 520 mm 2 / s, or 380 mm 2 / s to 520 mm 2 / s, or 450 mm 2 / s to 520 mm 2 / s), and any value and subset therebetween. The gear oil formulation has a kinematic viscosity (ASTM D445-21, 40 °C) that may include 20 mm 2 / s to 70 mm 2 / s (or 20 mm 2 / s to 36 mm2 / sec, or 27mm 2 / sec~36mm 2 / sec, or 36mm 2 / sec ~ 42mm 2 / sec, or 45mm 2 / sec~50mm 2 / second, or 60mm 2 / sec~70mm 2 It may have kinematic viscosity (ASTM D445-21, 100°C) encompassing any value and subset therein ( / second).

[0025] The gear oil formulation may have an acid value at pH 11.0 (ASTM D2893) of 0.2 mg KOH / g to 1.0 mg KOH / g (or 0.5 mg KOH / g to 1.0 mg KOH / g, or 0.5 mg KOH / g to 0.6 mg KOH / g, or 0.6 mg KOH / g to 0.7 mg KOH / g, or 0.7 mg KOH / g to 0.8 mg KOH / g, or 0.8 mg KOH / g to 0.9 mg KOH / g, or 0.9 mg KOH / g to 1.0 mg KOH / g), as well as any value and subset in between. The gear oil formulation may have an oxide D91 precipitation value in the range of less than 0.025 mL, including 0 mL, and encompassing any value and subsets in between. The gear oil formulation may have a viscosity index (ASTM D2270-16) that includes any value and subset between 120 and 180 (or 120 and 130, or 140 and 160, or 160 and 180, or 160 and 170).

[0026] The gear oil formulation may have a pour point (IP15 or ASTM D97) that encompasses any value and subset between -50°C and -20°C (or -45°C and -30°C, or -45°C and -39°C), as well as any value and subset between those ranges. Therefore, the gear oil formulations of this disclosure compete with fully synthetic gear oil formulations even when they do not contain pour point depressants. Furthermore, the gear oil formulations of this disclosure exhibit advantages in pressure viscosity coefficient and cost. Although not bound by theory, it is further conceivable that the gear oil formulations further improve elastohydrodynamic lubrication (EHL) film thickness (resulting in thicker EHL films), and thus significantly improve gear life and pitting (e.g., micropitting) performance compared to conventional gear oil formulations (e.g., conventional PAO-based gear oils). Each of the various base stock components of this disclosure is mixed according to one or more of the methods of this disclosure, and this mixture may, in some cases, be heated, for example, in a reaction vessel. Then, any solubilizers and any additives are added, and the mixture is homogenized, ensuring that it is thoroughly mixed and uniformly dispersed. The mixture is then cooled.

[0027] Furthermore, in one or more embodiments, at least the bright stocks and PAO base stocks of Group II are pre-blended. Additionally, two or more pre-blended mixtures can be blended themselves to achieve lower viscosity indices and lower kinematic viscosities (at 40°C and 100°C) compared to any one of the pre-blended mixtures alone. Alternatively, it should be noted that at least the bright stocks and PAO base stocks of Group II may be pre-blended without blending with additional pre-blended mixtures. To facilitate a better understanding of the embodiments of the present invention, the following examples are provided as preferred or representative embodiments. These examples should not be construed as limiting or defining the scope of the present invention. [Examples]

[0028] Example 1 In this example, a gear oil formulation containing a conventional synthetic PAO base stock ("control") was formulated and compared with a gear oil formulation according to a representative embodiment of this disclosure ("experiment"). The characteristics of various compositions were tested for both the control and experimental samples, and the formulations and results are given in Table 1 below. [Table 1]

[0029] Example 2 These examples provide various suitable formulations for the gear oil of the present disclosure, as listed in Table 2 below, each in mass percent. [Table 2] JPEG2026516456000003.jpg116155

[0030] Accordingly, the gear oil formulations of this disclosure provide formulations that are equivalent to or improved compared to more expensive, currently used high-performance synthetic PAO-based stock gear oils. While various embodiments have been described herein, those skilled in the art may modify them without departing from the scope of this disclosure. The embodiments described herein are representative examples only and are not intended to limit the scope. Many variations, combinations, and modifications of the embodiments disclosed herein are possible and are within the scope of this disclosure. Accordingly, the scope of protection is not limited by the descriptions presented above but is defined by the subsequent claims, which include all equivalents of the subject matter of the claims.

[0031] Exemplary Embodiments The embodiments include the following: Embodiment A: 250mm 2 / sec~600mm 2 Kinematic viscosity in 1 / second (ASTM D445, 40°C), 20 mm 2 / sec~70mm 2The first oil-based stock is a Group II bright stock having a kinematic viscosity of 1 / second (ASTM D445, 100°C), a viscosity index of 80-120 (ASTM D2270), and a pour point of -50°C--20°C (ASTM D97), as well as 500 mm 2 / sec~3500mm 2 Kinematic viscosity in 60 mm² / second (ASTM D445, 40°C), 60 mm 2 / sec~300mm 2 A gear oil composition comprising a second oil base stock which is a polyalphaolefin (PAO) base stock having a kinematic viscosity of 1 / second (ASTM D445, 100°C), a viscosity index of 150-250 (ASTM D2270), and a pour point of -50°C to -20°C (ASTM D97).

[0032] Embodiment B: A method comprising the step of mixing a first oil base stock and a second base stock, wherein the first base stock is 250 mm 2 / sec~600mm 2 Kinematic viscosity in 1 / second (ASTM D445, 40°C), 20 mm 2 / sec~70mm 2 A Group II bright stock having a kinematic viscosity of 1 / second (ASTM D445, 100°C), a viscosity index of 80-120 (ASTM D2270), and a pour point of -50°C--20°C (ASTM D97), with a second base stock of 500 mm 2 / sec~3500mm 2 Kinematic viscosity in 60 mm² / second (ASTM D445, 40°C), 60 mm 2 / second ~ mm 2 A method for a polyalphaolefin (PAO)-based stock having a kinematic viscosity of 1 / second (ASTM D445, 100°C), a viscosity index of 150-250 (ASTM D2270), and a pour point of -50°C to -20°C (ASTM D97). Embodiments A and B may each have one or more of the following additional elements in any combination.

[0033] Element 1: The first oil base stock is present in an amount of 15% to 50% by mass relative to the total mass of the gear oil composition. Element 2: The second oil base stock is present in an amount of 10% to 70% by mass relative to the total mass of the gear oil composition. Element 3: The second oil-based stock is selected from the group consisting of conventional light PAOs, conventional heavy PAOs, metallocene PAOs, and any combination thereof. Element 4: The second oil-based stock is metallocene PAO. Element 5: The first oil-based stock and the second oil-based stock are present in an amount of 60% to 99.5% by mass relative to the total mass of the gear oil composition.

[0034] Element 6: Further contains a solubilizing agent. Element 7: Further comprising a solubilizer, the solubilizer being selected from the group consisting of dibasic acids and alcohols, esters of monocarboxylic acids with 5 to 18 carbon atoms and polyols, polyoxyalkylene glycols, polyoxyalkylene glycol esters, polyoxyalkylene glycol ethers and phosphate esters, naphthalene compounds, and any combination thereof. Element 8: Further contains a solubilizer, the solubilizer present in an amount of 2.5% to 20% by mass relative to the total mass of the gear oil composition. Element 9: Further includes a third oil-based stock, the third oil-based stock being 15mm 2 / sec~600mm 2 Kinematic viscosity in 1 / second (ASTM D445, 40°C), 4 mm 2 / sec~60mm 2 This is a Group V base stock with a kinematic viscosity of 1 / second (ASTM D445, 100°C), a viscosity index of 80-200 (ASTM D2270), and a pour point of -60°C--20°C (ASTM D97). Element 10: Further comprising a third oil-based stock, wherein the first oil-based stock, the second oil-based stock, and the third oil-based stock are present in amounts of 60% to 99.5% by mass relative to the total mass of the gear oil composition.

[0035] Element 11: Further comprises at least one additive selected from the group consisting of ashless dispersants, pour point depressants, defoamers, antioxidants, rust inhibitors, friction modifiers, and any combination thereof. Element 12: Further comprises an ashless dispersant present in an amount of 0.05% to 5% by mass relative to the total mass of the gear oil composition. Element 13: Further comprises a pour point depressant present in an amount of 0.05% to 5% by mass relative to the total mass of the gear oil composition. Element 14: Further comprises an antifoaming agent present in an amount of 0.05% to 5% by mass relative to the total mass of the gear oil composition. Element 15: Further comprises an antioxidant present in an amount of 0.05% to 5% by mass relative to the total mass of the gear oil composition.

[0036] Element 16: Further comprises a rust inhibitor present in an amount of 0.05% to 5% by mass relative to the total mass of the gear oil composition. Element 17: Further comprises a friction modifier present in an amount of 0.05% to 5% by mass relative to the total mass of the gear oil composition. Element 18: Further includes low viscosity Group II-IV trim oil base stocks. Element 19: Gear oil is formulated for lubrication of the gearbox of a wind turbine. Element 20: If no pour point depressant is included, the gear oil has a pour point below -20°C.

[0037] Element 21: If no viscosity index improver is included, the gear oil has a viscosity index greater than 150. Element 22: The gear oil exhibits a thicker elastofluid lubrication film compared to conventional PAO-based gear oil compositions. Element 23: Gear oil is pre-blended and used in combination with a second pre-blended gear oil containing the composition described in claim 1, the combination exhibits a lower viscosity index and lower kinematic viscosity at 40°C and 100°C compared to each pre-blended composition alone. Element 24: The first oil-based stock is 288 mm 2 / sec~352mm 2 It has a kinematic viscosity of 1 / second (ASTM D445, 40°C). As a non-limiting example, typical combinations applicable to embodiments A and B include, but are not limited to, one, more, or all of elements 1 to 24.

[0038] Therefore, the present invention is well suited to achieving the mentioned objectives and benefits and those inherent therein. The specific examples and configurations disclosed above are illustrative only, and the present invention may be modified and performed in different but equivalent ways, which will be obvious to those skilled in the art who are interested in the teachings herein. Furthermore, except as described in the following claims, no limitation is intended to the details of the construction or design shown herein. For this reason, it is obvious that the specific exemplary configurations disclosed above may be modified, combined or modified, and that all such variations are considered to fall within the scope and spirit of the present invention. The present invention disclosed herein illustratively may be well performed without any elements not specifically disclosed herein and / or any elements disclosed herein. Compositions and methods are described using the terms “comprising,” “containing,” or “including” various components or steps, but compositions and methods may also “consist essentially of” or “consist of” various components and steps. All figures and scopes disclosed above are subject to some degree of variation. Whenever a numerical range with lower and upper limits is disclosed, in particular any number and any range that falls within that range is disclosed. In particular, all ranges of values ​​disclosed herein (in the form of “about a to about b,” or equivalent “approximately a to b,” or equivalent “approximately a to b”) should be understood to describe all numbers and ranges that fall within a broader range of values. Furthermore, terms in the claims have plain, ordinary meanings unless explicitly and clearly defined by the patent holder. In addition, the indefinite article “a” or “an” used in the claims is defined herein to mean one or more of the elements being introduced.

[0039] Unless otherwise indicated, all numbers used herein and in the associated claims to represent quantities, properties, such as molecular weight, reaction conditions, etc., of components should be understood in all cases to be modified with the term “approximately.” Therefore, unless otherwise indicated, the numerical parameters described in the following specification and the appended claims are approximations that may vary depending on the desired properties to be obtained by the embodiment of the invention. At the very least, without attempting to limit the application of the doctrine of equivalents to the claims, each numerical parameter should be interpreted using common rounding techniques, taking into account at least the number of significant figures reported.

[0040] This specification presents one or more exemplary embodiments incorporating one or more inventive elements. For clarity, not all features of physical implementations are described or shown in this application. In developing physical embodiments incorporating one or more elements of the present invention, it is understood that numerous implementation-specific decisions must be made to achieve the developer's goals, such as compliance with system-related, business-related, government-related, and other constraints that vary from implementation to implementation and over time. While the developer's efforts may be time-consuming, such efforts are nevertheless routine for those skilled in the art and are of interest to this disclosure.

Claims

1. 250mm 2 / sec ~ 600mm 2 kinematic viscosity per second (ASTM D445, 40°C), 20mm 2 / sec ~ 70mm 2 kinematic viscosity per second (ASTM D445, 100°C), Viscosity index of 80 to 120 (ASTM D2270), and Pour point between -50°C and -20°C (ASTM D97) A first oil-based stock which is a bright stock of Group II having, 500mm 2 / sec ~ 3500mm 2 kinematic viscosity per second (ASTM D445, 40°C), 60mm 2 / sec ~ 300mm 2 kinematic viscosity per second (ASTM D445, 100°C), Viscosity index of 150 to 250 (ASTM D2270), and Pour point between -50°C and -20°C (ASTM D97) A second oil-based stock is a polyalphaolefin (PAO)-based stock having, A gear oil composition containing [the specified ingredient].

2. The gear oil composition according to claim 1, wherein the first oil base stock is present in an amount of 15% to 50% by mass relative to the total mass of the gear oil composition.

3. The gear oil composition according to claim 1, wherein the second oil base stock is present in an amount of 10% to 70% by mass relative to the total mass of the gear oil composition.

4. The gear oil composition according to claim 1, wherein the second oil base stock is selected from the group consisting of conventional light PAO, conventional heavy PAO, metallocene PAO, and any combination thereof.

5. The gear oil composition according to claim 1, wherein the first oil base stock and the second oil base stock are present in an amount of 60% to 99.5% by mass relative to the total mass of the gear oil composition.

6. The gear oil composition according to claim 1, further comprising a solubilizer, wherein the solubilizer is selected from the group consisting of dibasic acids and alcohols, esters of monocarboxylic acids having 5 to 18 carbon atoms and polyols, polyoxyalkylene glycols, polyoxyalkylene glycol esters, polyoxyalkylene glycol ethers and phosphate esters, naphthalene compounds, and any combination thereof.

7. Further comprising a third oil-based stock, the third oil-based stock is 15 mm 2 / sec to 600 mm 2 / sec kinematic viscosity (ASTM D445, 40 °C), 4mm 2 / second ~60mm 2 Kinematic viscosity per second (ASTM D445, 100°C) Viscosity index of 80 to 200 (ASTM D2270), and Pour point of -60°C to -20°C (ASTM D97) The gear oil composition according to claim 1, which is a base stock of group V having the following:

8. The gear oil composition according to claim 7, wherein the first oil base stock, the second oil base stock, and the third oil base stock are present in an amount of 60% to 99.5% by mass relative to the total mass of the gear oil composition.

9. The gear oil composition according to claim 1, further comprising at least one additive selected from the group consisting of ashless dispersants, pour point depressants, defoaming agents, antioxidants, rust inhibitors, friction modifiers, and any combination thereof.

10. The gear oil composition according to claim 1, further comprising an ashless dispersant present in an amount of 0.05% to 5% by mass relative to the total mass of the gear oil composition.

11. The gear oil composition according to claim 1, further comprising a pour point depressant present in an amount of 0.05% to 5% by mass relative to the total mass of the gear oil composition.

12. The gear oil composition according to claim 1, further comprising an antifoaming agent present in an amount of 0.05% to 5% by mass relative to the total mass of the gear oil composition.

13. The gear oil composition according to claim 1, further comprising: (1) an antioxidant present in an amount of 0.05% to 5% by mass relative to the total mass of the gear oil composition; (2) a rust inhibitor present in an amount of 0.05% to 5% by mass relative to the total mass of the gear oil composition; or both of (1) and (2).

14. The gear oil composition according to claim 1, further comprising a friction modifier present in an amount of 0.05% to 5% by mass relative to the total mass of the gear oil composition.

15. The gear oil composition according to claim 1, wherein, in the absence of a pour point depressant, the gear oil has a pour point of less than -20°C.

16. The gear oil composition according to claim 1, wherein, in the absence of a viscosity index improver, the gear oil has a viscosity index greater than 150.

17. The gear oil composition according to claim 1, wherein the gear oil is pre-blended and used in combination with a second pre-blended gear oil containing the composition according to claim 1, the combination exhibits a lower viscosity index and lower kinematic viscosity at 40°C and 100°C compared to each of the pre-blended compositions alone.

18. The aforementioned first oil base stock is 288 mm 2 / sec ~ 352mm 2 The gear oil composition according to claim 1, having a kinematic viscosity of 0 / second (ASTM D445, 40°C).

19. The step of mixing a first oil-based stock and a second base stock, The first base stock described above is 250mm 2 / sec ~ 600mm 2 kinematic viscosity per second (ASTM D445, 40°C), 20mm 2 / sec ~ 70mm 2 kinematic viscosity per second (ASTM D445, 100°C), Viscosity index of 80 to 120 (ASTM D2270), and Pour point between -50°C and -20°C (ASTM D97) It is a brightstock of Group II that has the following characteristics: The aforementioned second base stock, 500mm 2 / sec ~ 3500mm 2 kinematic viscosity per second (ASTM D445, 40°C), 60mm 2 / sec ~ 300mm 2 kinematic viscosity per second (ASTM D445, 100°C), Viscosity index of 150 to 250 (ASTM D2270), and Pour point between -50°C and -20°C (ASTM D97) A polyalphaolefin (PAO) base stock having the step Methods that include...

20. Further comprising a third oil-based stock, the third oil-based stock is 15mm 2 / sec ~ 600mm 2 kinematic viscosity per second (ASTM D445, 40°C), 4mm 2 / second ~60mm 2 Kinematic viscosity per second (ASTM D445, 100°C) Viscosity index of 80 to 200 (ASTM D2270), and Pour point of -60°C to -20°C (ASTM D97) The method according to claim 19, wherein the base stock of group V is having

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