JP2011522930A - GEAR OIL COMPOSITION, PROCESS FOR PRODUCTION AND USE - Google Patents

Abstract

A gear oil composition is provided. The oil composition is at least 16.0 at a traction coefficient of 0.030 or less at a slip / rolling ratio of 40 percent at 15 mm ² / sec, at 80 ° C., a load of 20 Newtons, and a rolling speed of 1.1 m / sec. The composition includes a synergistic mixture of a mineral oil base material and a polyalphaolefin (PAO) base material so as to have a pressure viscosity coefficient. In certain embodiments, the synergistic amount of PAO base stock ranges from 5 to 48% by weight based on the total weight of the gear oil composition.

Description

  The present invention relates generally to compositions suitable for use as lubricants, and more particularly for use as gear oils.

  Gear oil is used in industrial applications as power devices (collectively referred to as “devices”) for automobiles, tractors and the like. In some applications, gear oil exists as an oil film between moving parts, for example traction drives. In traction drive applications, force is transmitted through the gear oil film. In some applications, such as the hypoid gear, which is the final reduction gear, it is highly desirable that a thick oil film be formed / held between the gears. By increasing the thickness of the oil film to a sufficient level, the friction surface can be protected from damage, and the fatigue life and load bearing characteristics of the gear and / or bearing are greatly improved.

  The traction coefficient is the force required to move the load divided by the load. This coefficient represents the ease of shearing of the lubricating film. Since the smaller the traction coefficient, the less energy is lost due to the shearing of the lubricant, it is desirable for the gear oil to have a smaller traction coefficient.

  In addition to having a small traction coefficient, it is important that the gear oil has a large pressure-viscosity coefficient. The pressure-viscosity coefficient (“PVC”) is the load (pressure) applied to the oil film in the dynamic load region and the load when all other factors (material, temperature, shape, speed, load) are constant. It refers to the relationship between the oil film thickness (viscosity). The pressure-viscosity coefficient of gear oil is a given set of conditions (also known as EHL or EHD schemes) based on mathematical assumptions as described in the information sheet AGMA925-A03 of the American Gear Manufacturers Association (AGMA) This is a fixed value for the oil film thickness in the elastohydrodynamic system. It is desirable for the gear oil to have a large PVC value.

US Patent Publication No. 2007/0027042 describes two mineral base oils and / or hydrocarbon based synthetic oils of different kinematic viscosities, 3.5 to 7 mm ² / sec at 100 ° C. and from 20 at 100 ° C. Gear oil compositions including those of 52 mm ² / sec are disclosed. US Patent Publication No. 2007/0078070 includes a gear oil composition comprising at least one Group II base stock and at least one low volatility low viscosity polyalphaolefin base stock. Things are disclosed.

  There is still a need for gear oil compositions having low traction coefficient, large pressure-viscosity coefficient, and optimum film thickness characteristics.

In certain embodiments, the present invention is synergistic comprising at least a) a mineral oil base stock having a kinematic viscosity at 100 ° C. of 3 to 120 mm ² / sec and a viscosity index of at least 60; and a polyalphaolefin base stock. A base oil containing a mixture (synergistic mixture), and b) at least a traction reducing agent, a dispersant, a viscosity modifier, a pour point depressant, an antifoaming agent, an antioxidant, a rust inhibitor, a metal passivating agent, an electrode For a gear oil composition comprising 0.001 to 30 wt% additive selected from pressure additives, friction modifiers, and mixtures thereof, wherein the polyalphaolefin is 40 percent in the gear oil composition a traction coefficient at 0.030 15 mm ² / s or less sliding / rolling ratio (slide to roll ratio), 80 , Present in a synergistic amount for having a pressure viscosity coefficient of at least 16.0GPa ^-1 at 20 Newton load, and 1.1 m / s rolling speeds (rolling speed) (synergistic amount) .

In another aspect, the present invention provides a base oil commonly used to prepare gear oils with a synergistic amount of polyalphaolefin for the gear oil to have a traction coefficient at 15 mm ² / sec of 0.030 or less. It is related with the method of improving the traction coefficient characteristic of a gear oil including adding at least. In certain embodiments, the sufficient amount of polyalphaolefin to be added to the base oil matrix ranges from 5 to 48% by weight based on the total weight of the gear oil composition.

It is the graph which compared the pressure-viscosity coefficient of the gear composition of Examples 1-5 in various temperature. It is the graph which compared the film thickness of the gear composition of Examples 1-5 in various temperature.

  The following terms are used throughout the specification and have the following meanings unless otherwise indicated.

“Kinematic viscosity” is the resistance to fluid flow measured under gravity in mm ² / sec and is measured according to ASTM D445-06.

  “Viscosity Index” (VI) is an experimental unitless number that indicates the effect of temperature change on the kinematic viscosity of an oil. The greater the VI of the oil, the less the oil viscosity tends to change with temperature. The viscosity index is measured according to ASTM D2270-04.

  The low temperature cranking simulator apparent viscosity (CCS VIS) is used to measure the viscosity properties of lubricating base oils under low temperature and high shear, in millipascal seconds, mPa. measured in s. CCS VIS is measured according to ASTM D5293-04.

  The boiling range distribution of the base oil by weight% is ASTM D6352-04, “Boiling Range Distributions of Petroleum Distillates in Boiling Range from 174 by Gas Chromatography. to 700 ° C. by Gas Chromatography.) ”by means of simulated distillation (SIMDIS).

  “Noak volatility” is defined as the mass of oil lost when an oil is heated at 250 ° C. and a constant flow of air is passed through the oil for 60 minutes, expressed as weight percent, ASTM D5800-05, procedure. Measured by B.

  Brookfield viscosity is used to measure fluid friction within a lubricant during cold operation and can be measured according to ASTM D2983-04.

  "Pour point" is measured as the temperature at which a sample of base oil begins to flow under certain carefully controlled conditions and can be measured as described in ASTM D5950-02.

  “Auto ignition temperature” is the temperature at which a fluid spontaneously ignites when it comes into contact with air, and can be measured according to ASTM 659-78.

  “Traction coefficient” is an index of an inherent lubrication characteristic expressed as a dimensionless ratio between the friction force F and the normal force N, where friction is the sliding or rolling surface. A mechanical force that resists or prevents movement in between. The traction coefficient was measured by PCS Instruments, Ltd., which consisted of a flat polished disc (SAE AISI 52100 steel) with a diameter of 46 mm and a polished ball (SAE AISI 52100 steel) with an angle of 22 ° and a diameter of 19 mm. From the MTM Tracture Measurement System. Steel balls and discs are independently measured at an average rolling speed of 3 meters per second, a slip / rolling ratio of 40 percent, and a load of 20 Newtons. The rolling ratio is the difference in the sliding speed between the ball and disk divided by the average speed of the ball and disk, ie rolling ratio = (speed 1−speed 2) / ((speed 1 + speed 2) / 2. ).

  Molecular weight is measured according to ASTM D2503-92 (Reapproved 2002). This method uses a thermoelectric measurement of vapor pressure (VPO). In situations where the sample volume is inadequate, an alternative method, ASTM D2502-04, can be used, which is indicated when used.

  Density is measured according to ASTM D4052-96 (Reapproved 2002). A sample is introduced into a vibrated sample tube and the vibration frequency change caused by the mass change of the tube is used along with calibration data to Measure density.

Component A-Group V polyalphaolefins ("PAOs")
Component A of the base oil matrix is a Group IV base oil or a mixture of different Group IV base oils. Group IV base stock consists of polyalphaolefins (“PAOs”) and relies on additives relative to the volatility, thermal stability, oxidation stability and pour point characteristics of Group II and III oils Excellent volatility, thermal stability, oxidation stability and pour point characteristics.

  PAOs include a class of hydrocarbons produced by catalytic oligomerization (polymerization to low molecular weight products) of linear α-olefins, generally in the range of 1-octene to 1-dodecene, Polymers of lower olefins such as ethylene and propylene, including copolymers with higher olefins can also be used. High viscosity PAOs such as aluminum trichloride, boron trifluoride, or boron trifluoride complexes with water, alcohols such as ethanol, propanol or butanol, carboxylic acids, or esters such as ethyl acetate or ethyl propionate. It can be conveniently prepared by polymerizing an α-olefin in the presence of a polymerization catalyst such as a Friedel-Crafts catalyst.

In some embodiments, the PAO used is predominantly alpha-olefins, ie linear terminal olefins. It mainly means that the PAO contains more than about 50 mole percent α-olefin. In another embodiment, the PAO is a high viscosity PAO and comprises a hydrogenated polymer or oligomer of an α-olefin. Alpha-olefins include, but are not limited to, C ₂ to about C ₃₂ alpha-olefins such as 1-octene, 1-decene, 1-dodecene, and the like. In certain embodiments, the PAO is an α-olefin selected from the group of poly-1-octene, poly-1-decene, and poly-1-dodecene.

The PAO product used in the composition is a low viscosity, high molecular weight viscous material having a viscosity greater than 1000 mm ² / sec (cSt.) At 100 ° C. from a high mobility fluid of about 2 mm ² / sec at 100 ° C. Can have a wide range of viscosities up to. In certain embodiments, the PAO product has a viscosity in the range of 40 to 500 mm ² / sec (cSt.) At 40 ° C. In certain embodiments, the PAO used as component A has a viscosity of about 80 mm ² / sec or more at 40 ° C. and about 20 mm ² / sec or less at 100 ° C. In another embodiment, PAO base stock has a kinematic viscosity at 40 ° C. in the range of 80~110mm ² / s, kinematic viscosity at 100 ° C. for 10~16mm ² / s, and a viscosity index of 140 to 160 . In yet another embodiment, PAO base stock is a mixture of different PAO, PAO mixture, in order to have a viscosity of 100 mm ² / s at 40 ° C., one from 30 at 40 ° C. 60 mm ² / It has a viscosity in the range of seconds and the remainder has a viscosity of 300-600 mm ² / second at 40 ° C.

Component B-Mineral Oil Component B is a mineral oil or a mixture of mineral oils. The mineral oil can be either paraffinic oil and naphthenic oil, or mixtures thereof. The lubricating oil fraction produced by atmospheric distillation or vacuum distillation of crude oil can be used for solvent removal history, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrorefining, sulfuric acid treatment, clay treatment, etc. Mineral oil can be obtained by subjecting it to seed or multiple refining steps.

  In one embodiment, the mineral oil used as component B is an amount of synthetic oil, such as poly-α-olefin, ethylene-α-olefin copolymer and ester-based synthetic oil, 50% of the total weight of the gear oil composition. It can contain in the quantity of the weight% or less.

In certain embodiments, Component B is a mineral oil (or mixture of mineral oil and / or hydrocarbon-based synthetic oil) having a kinematic viscosity at 100 ° C. of 3 to 120 mm ² / sec and a viscosity index of at least 60. . In another embodiment, Component B is a mineral oil having a kinematic viscosity at 100 ° C. of 2.3 to 3.4 mm ² / sec and having an a% Cp of 70 or greater as defined by ASTM D3238 (R2000). ASTM D3238 is a standard test method for calculating carbon distribution and is a structural group analysis of petroleum by the ndM method. In yet another embodiment, Component B is a base oil matrix having a kinematic viscosity of less than 80 mm ² / sec at 40 ° C. and a “low viscosity” having a kinematic viscosity of 3.5 to 7 mm ² / sec at 100 ° C. And a high-viscosity mineral and / or hydrocarbon-based synthetic oil having a kinematic viscosity at 100 ° C. of 20 to 52 mm ² / sec.

In certain embodiments, the base oil matrix has a kinematic viscosity at 100 ° C. between 10 mm ² / sec and 15 mm ² / sec and a kinematic viscosity at 40 ° C. between 95 mm ² / sec and 110 mm ² / sec. It contains a sufficient amount of mineral oil and PAO oil to have a viscosity and a viscosity index between 95 and 175.

Incorporation of additional optional synergistic amounts of mineral oil and PAO oil allows the composition to have a low traction coefficient without the need for traction reducers in the prior art. However, in certain embodiments, a small amount of traction reducing agent, such as 0.5 to 10% by weight, can be incorporated into the gear oil composition. Examples of traction reducers include ExxonMobil's Norpar ™ fluid (contains normal paraffin), Isopar ™ fluid (contains isoparaffin), Exxsol ™ fluid (dearomatized carbonized) Hydrogen fluid), Varsol ™ fluid (including aliphatic hydrocarbon fluid), and mixtures thereof.

  In certain embodiments, the gear oil composition may be used in combination with dispersants, viscosity index improvers, pour point depressants, antifoams to meet a variety of properties such as those related to friction, oxidation stability, cleanliness, and defoaming. 1 to 30% by weight of one or more additives selected from agents, antioxidants, rust inhibitors, metal passivators, extreme pressure additives, friction modifiers, etc.

  Examples of the dispersant include those based on polybutenyl succinimide, polybutenyl succinamide, benzylamine, succinate, succinate-amide, and boron derivatives thereof. If used, ashless dispersants are generally used in amounts of 0.05 to 7% by weight. In certain embodiments, the dispersant comprises a hydrocarbon-substituted acid anhydride made by reacting a polyolefin having a molecular weight of about 700-1400 with an unsaturated polycarboxylic acid or acid anhydride, such as maleic anhydride, and polyethylene. Selected from reaction products with polyamines such as triethylenetetraaminepentamine.

  Examples of metal detergents include those containing sulfonates such as calcium, magnesium or barium, phenol salts, salicylates. When metal detergents are used, they are generally incorporated in amounts of 0.05 to 5% by weight.

  Examples of antioxidants include amines such as alkylated diphenylamine, phenyl-α-naphthylamine and alkylated phenyl-x-naphthylamine and phenolic ones such as 2,6-di-t-butylphenol, 4 , 4′-methylenebis (2,6-di-t-butylphenol) and isooctyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate and sulfur-based ones such as dilauryl-3, 3'-thiodipropionate and zinc dithiophosphate are included, but are not limited thereto. When an antioxidant is used, it is incorporated in an amount of 0.05 to 5% by weight.

  Antifoam can be optionally incorporated in an amount of 10-100 ppm. Examples of antifoaming agents include, but are not limited to, dimethylpolysiloxane, polyacrylates and their fluorine derivatives, and perfluoropolyethers. Rust inhibitors can be used in amounts of 0 to 30% by weight. Examples include fatty acids, alkenyl succinic acid half esters, fatty acid soaps, alkyl sulfonates, polyhydric alcohols / fatty acid esters, fatty acid amines, oxidized paraffins and alkyl polyoxyethylene ethers.

  Friction modifiers can be incorporated in amounts of 0.05 to 5% by weight. Examples include organomolybdenum compounds, fatty acids, higher alcohols, fatty acid esters, sulfurized esters, phosphate esters, acidic phosphate esters, acidic phosphorus-containing acid esters, and amine salts of phosphate esters. It is not limited.

Antiwear and / or extreme pressure additives can be incorporated in amounts of 0.1 or 10% by weight. Examples of antiwear and / or extreme pressure additives include non-metal-containing sulfur-containing species including sulfurized olefins, dialkyl polysulfides, diaryl polysulfides, sulfurized fats and oils, sulfurized fatty acid esters, trithiones, C2- C8 monoolefin sulfide oligomers, thiophosphate compounds, sulfurized terpenes, thiocarbamate compounds, thiocarboxylate compounds, sulfoxides, sulfinate thiols, and the like are included. Other examples include metal-free-phosphorus-containing wear resistance, such as esters of phosphorus-containing acids, amine salts of phosphorus-containing acids, and phosphorus-containing acid esters, and the partial and complete thio analogs described above. Additives and / or extreme pressure additives are included. In certain embodiments, the composition comprises acidic phosphate as an antiwear agent, and the agent has the formula R ₁ O (R ₂ O) P (O) OH, wherein R ₁ is Hydrogen or hydrocarbyl and R ₂ is hydrocarbyl.

  Pour point depressants can be incorporated in amounts ranging from 0.05 to 10% by weight. Examples include ethylene / vinyl acetate copolymers, chlorinated paraffin and naphthalene condensates, chlorinated paraffin and phenol condensates, polymethacrylates, polyalkylstyrenes, chlorinated wax-naphthalene condensates, and vinyl acetate-fumaric acid. Although ester copolymer etc. are included, it is not limited to them.

  In certain embodiments, the composition further comprises at least one of polyoxyalkylene glycol, polyoxyalkylene glycol ether, and ester as a solubilizing agent in an amount of 10 to 25% by weight. Examples include esters of dibasic acids (eg, phthalic acid, succinic acid, alkyl succinic acid, alkenyl succinic acid, maleic acid, azelaic acid, suberic acid, sebacic acid, fumaric acid or adipic acid, or linoleic acid dimer) , Alcohols (eg butyl alcohol, hexyl alcohol, 2-ethylhexyl alcohol, dodecyl alcohol, ethylene glycol, diethylene glycol monoether or propylene glycol), monocarboxylic esters of 5 to 18 carbon atoms, and polyols (eg neo Pentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol or tripentaerythritol), polyoxyalkylene glycol esters, and phosphate esters.

  In certain embodiments, the composition further comprises at least a metal passivating agent, sometimes specifically a copper passivating agent. Examples include thiazole, triazole and thiadiazole. Specific examples of thiazole and thiadiazole include 2-mercapto-1,3,4-thiadiazole, 2-mercapto-5-hydrocarbylthio-1,3,4-thiadiazole, 2-mercapto-5-hydrocarbyldithio-1,3. , 4-thiadiazole, 2,5-bis- (hydrocarbylthio) -1,3,4-thiadiazole and 2,5-bis- (hydrocarbyldithio) -1,3,4-thiadiazole are included. Other suitable copper corrosion inhibitors include the imidazolines described above and the like.

  In certain embodiments, the composition further comprises at least a viscosity modifier in an amount of 0.50 to 10% by weight. Examples of viscosity modifiers include, but are not limited to, groups of polymethacrylate type polymers, ethylene-propylene copolymers, styrene-isoprene copolymers, hydrated styrene-isoprene copolymers, polyisobutylene, and mixtures thereof. It is not a thing. In certain embodiments, the viscosity modifier comprises a polymethacrylate having a weight average molecular weight of 25,000 to 150,000 and a shear stability index of less than 5, a weight average molecular weight of 500,000 to 1,000,000, and 25 to 60. It is a mixture with polymethacrylate having a shear stability index.

  The gear oil composition of the present invention comprises a synergistic amount of mineral feedstock and PAO base stock so that the composition has low traction coefficient, high pressure-viscosity coefficient, and optimal film thickness characteristics. It is characterized by having. In certain embodiments, this synergistic amount of PAO base stock ranges from 5 to 48% (based on the total weight of the gear oil composition). In a second embodiment, the synergistic amount of PAO base material ranges from 15 to 40% by weight. In a third embodiment, the synergistic amount of PAO base material ranges from 25-30% by weight. In a fourth embodiment, the synergistic amount of PAO base material is at least 40% by weight. In a fifth embodiment, the synergistic amount of PAO base material ranges from 10 to 35% by weight.

In certain embodiments, the gear oil has a kinematic viscosity at 40 ° C. of 70~120mm ² / s, kinematic viscosity at 100 ° C. of 12 to 18 mm ² / sec, and PAO base stock 5 having a viscosity index of 130 to 160 48% by weight (based on the total weight of the gear oil composition), kinematic viscosity at 40 ° C. of 40~120mm ² / s, kinematic viscosity at 100 ° C. for 8 to 14 mm ² / s, and a viscosity index of 80 to 120 Having a mixture of 25 to 75% by weight of a Group II neutral base oil.

In certain embodiments, a gear oil composition having a synergistic combination of a mineral base oil and an isomerized base oil has a traction coefficient at 15 mm ² / sec of 0.030 or less, 80 ° C., 20 Newtons. It has a pressure viscosity coefficient of more than 15.0 GPa ⁻¹ and a film thickness at 80 ° C. of more than 175 nm at a load and a rolling speed of 1.1 m / sec. In another embodiment, the gear oil composition has a film thickness of at least 160 nm at 90 ° C., or 130 nm at 100 ° C. In a third embodiment, the gear oil composition has a pressure viscosity coefficient of at least 15.5 GPa ⁻¹ at a temperature in the range of 70-100 ° C., a load of 20 Newtons, and a rolling speed of 1.1 m / sec. Have. In a fourth embodiment, the gear oil composition has a traction coefficient at 15 mm ² / sec of 0.030 or less at a 40 percent slip / roll ratio.

In one embodiment for use as automotive gear oil, the composition meets SAE J306 specifications for a specified viscosity grade. For example, under the SAE J306 standard, the viscosity of SAE 90 gear oil measured at 100 ° C. (212 ° F.) should exceed 13.5 mm ² / sec after 20 hours of testing.

  In yet another embodiment, the composition meets at least one of the quality standards of industry standards SAE J2360, API GL-5 and API MT-1, and military standard MIL-PRF-2105E.

Method of Preparation The additives used in formulating the gear oil composition can be mixed into the base oil mixture individually or in various sub-combinations. In some embodiments, all ingredients are mixed simultaneously using an additive concentrate (ie, an additive with a diluent such as a hydrocarbon solvent). The use of additive concentrates takes advantage of the mutual compatibility provided by the combination of ingredients when in the form of additive concentrates.

  In another embodiment, the composition is prepared by mixing the base oil and additive (s) until uniform at an appropriate temperature, eg, 60 ° C.

Applications The composition is also useful in any system that includes any type of gear and elements or parts that contain rolling element bearings. In certain embodiments, the composition lubricates industrial gear such as spur and bevel gears, spiral and spiral bevel gears, hypoids and worm gears, and the like. It is used as gear oil. In another embodiment, the composition includes aircraft propulsion systems, aircraft transmissions, wind turbine gears, automobile drivetrains, transmissions, transfer cases, and differentials in automobiles, trucks and other machines. Used in automotive / mobile equipment applications and parts. In yet another embodiment, the composition is used in wind turbines, plastic extrusion gearboxes, and high-load gearboxes used in power generation systems or paper, steel, petroleum, fiber, wood and cement industries, etc. Used.

  The following examples are given as non-limiting illustrations of aspects of the present invention. Unless otherwise specified, the ingredients in the examples are as follows (expressed in weight percent in Table 1).

  RLOP is a Chevron® 600R Group II neutral heavy oil from Chevron Corporation.

  PAO8 includes Synfluid® PAO8cSt Chevron Phillips with a kinematic viscosity at 100 ° C of about 7.8, a kinematic viscosity at 40 ° C of 46.6, a viscosity index of 138, and a pour point of -57 ° C. Highly branched isoparaffinic polyalphaolefins commercially available from various sources.

  PAO40 is available in a variety of feeds including Synfluid® PAO40cSt Chevron Phillips with a kinematic viscosity at 100 ° C of about 40, a kinematic viscosity at 40 ° C of 410, a viscosity index of 145, and a pour point of -34 ° C. It is a highly branched isoparaffinic polyalphaolefin that is commercially available from the beginning.

  Additive X is a sulfur phosphorus-containing extreme pressure additive for industrial gears commercially available from various suppliers.

  Kinematic viscosity, refractive index and density are properties of the base oil matrix mixture, measured using methods known in the art. The traction coefficient of the gear oil in the examples is determined by methods and equipment known in the art, such as the traction coefficient measuring instrument disclosed in US Pat. No. 6,691,551, or elastohydrodynamics under high pressure of at least 300000 psi ( EHD) measurement / calculation using a two-disc device designed by Santotrac for measurement.

  The EHL film thickness is calculated using methods known in the art, for example, Equation 65 of the information sheet AGMA 925 of the American Gear Manufacturers Association (AGMA), where the EHL film thickness is determined by the operating temperature of the component. The thickness of the oil film is determined by the oil's response to the surface shape, temperature and speed at the contact inlet. The thickness is strongly dependent on the entraining velocity and the viscosity of the oil. The pressure-viscosity coefficient ("PVC") quantifies the ability of gear oil to produce an EHL film, which can be measured by known methods. PVC can be measured directly by calculating viscosity as a function of pressure using high pressure equipment or indirectly by measuring film thickness with an optical interferometer. PVC is the slope of a graph plotting logarithm of viscosity (log) versus pressure.

  From the experimental results, the synergistic addition of at least a PAO base material to mineral oil promotes the improvement of the traction coefficient of the gear oil composition, reduces the traction coefficient by at least 10%, and is less than 0.030 at 15 ° C. And a value of 0.028 or less for a composition containing at least 25 to 75% by weight of a PAO base material. From this data, a low traction coefficient (by incorporating a synergistic amount of PAO base stock into the base oil matrix of the gear oil composition of the prior art, eg, a base oil matrix containing mineral oil (s). Gear oil compositions having the desired optimal properties of high pressure viscosity coefficient, i.e., PVC (e.g., temperatures above 65 ° C.-> 15.0 at typical temperatures of gear components), for example. You can see that it is provided. Surprisingly, the PVC value is reduced by a composition containing 50-75% PAO by adding an excess amount of PAO because the PVC value is lower than that of pure PAO or pure mineral composition Sometimes. Therefore, in these cases, conflicting effects were observed.

1 and 2 are graphs comparing gear oil example film thicknesses (corrected refractive index) and pressure-viscosity coefficients as a function of temperature. As shown in FIG. 1, a gear oil composition consisting essentially of Group II neutral oil in the prior art has a relatively common PVC profile that shows a downward trend towards about 14.5 GPa ⁻¹ or less at 100 ° C. Indicates. A gear oil composition consisting essentially of at least a PAO base material exhibits a PVC value less than Group II oil within the range of 60-70 ° C, the PVC value being less than about 15 GPa ^-1 below 70 ° C. Yes, a PVC value of 13.5 GPa ⁻¹ at about 60 ° C. As shown in this example, by combining a prior art base oil with a synergistic amount of PAO base stock (eg, 75% RLOP600R and 25% PAO), a wide range of 60-100 ° C. In the range, the PVC value is markedly improved, with a value above 19 GPa ^{−1 at} about 80 ° C. Also, as shown, this composition has an excellent synergistic effect with PVC values measured at 80 ° C. and 100 ° C., greater than the corresponding values of either PAO base oil alone or Group II only gear oil. Indicates. Surprisingly, combinations containing excess amounts of PAO show the opposite effect. A composition containing 50% or more of PAO exhibits a PVC value at 80 ° C. that is less than the corresponding PVC value for either the PAO base oil alone or the prior art Group II only gear oil. The most conflict is observed for compositions containing a small amount of Group II neutral base oil and a large amount of PAO base stock (ie, 25% RLOP600R and 75% PAO). This composition exhibited a conflicting decrease in PVC value within the range of 60-80 ° C.

  For purposes of this specification and the appended claims, all numbers representing amounts, percentages or ratios, and other numbers used in this specification and claims, unless otherwise indicated. Numeric values are to be understood as being modified by the term “about” in all cases. Accordingly, unless indicated to the contrary, the number of parameters set forth in the following specification, and in the appended claims, depends on the desired property and / or value to be measured. Since it is an approximation that can vary with accuracy, it includes the standard deviation of the error for the instrument or method used to measure the value. The use of the term “or” in the claims is used to refer to “and / or” unless it explicitly refers only to the option, or if the option is not mutually exclusive, The disclosure supports definitions that refer only to options and “and / or”. The use of the terms “a” and “an” may mean “one” when used in connection with the term “comprising” in the claims and / or the specification. It is also consistent with the meaning of “one or more”, “at least one” and “one or more”. Moreover, all ranges disclosed herein contain endpoints and can overlap independently. In general, unless otherwise indicated, a singular element may be plural and vice versa. As used herein, the term “including”, and grammatical variations thereof, does not exclude an enumeration of items in a list from other similar items that can be substituted or added to the listed items. As such, it is intended to be non-limiting.

It is contemplated that any aspect of the invention discussed in the context of an embodiment of the invention can be implemented and applied to any other embodiment of the invention. Similarly, any composition of the present invention can be the result or used in any method or process of the present invention. This written description uses examples to disclose the invention, including the best mode, and also allows any person skilled in the art to make and use the invention. The patentable scope is defined by the claims, and may include other examples that occur to those skilled in the art. Such other embodiments have structural elements that do not differ from the wording of the claims, or equivalent structural elements that do not substantively differ from the wording of the claims. Such other embodiments are intended to be within the scope of the following claims. All citations referred to herein are expressly incorporated herein by reference.

Claims (14)

a) a base oil comprising a mixture comprising at least a mineral oil base stock having a kinematic viscosity at 100 ° C. of 3 to 120 mm ² / sec and a viscosity index of at least 60; and a polyalphaolefin (PAO) base stock;
b) at least traction reducers, dispersants, viscosity modifiers, pour point depressants, antifoaming agents, antioxidants, rust inhibitors, metal passivators, extreme pressure additives, friction modifiers, and mixtures thereof A gear oil composition comprising 0.001 to 30% by weight of an additive selected from
The gear oil composition has a traction coefficient at 15 mm ² / sec of 0.030 or less with a 40 percent slip / roll ratio, a load of 80 ° C., a load of 20 Newtons, and a rolling speed of 1.1 m / sec. The gear oil composition described above, wherein the polyalphaolefin base stock is present in a synergistic amount to have a pressure viscosity coefficient of ⁰ GPa- ¹ . PAO group in a synergistic amount for the gear oil to have a pressure viscosity coefficient of at least 15.5 GPa ⁻¹ at a temperature range of 70-100 ° C., a load of 20 Newtons, and a rolling speed of 1.1 m / sec. The composition according to claim 1, wherein an agent raw material is present.   The composition of claim 1, wherein the PAO base stock is present in an amount ranging from 5 to 48 wt%, based on the total weight of the gear oil composition.   The PAO base stock is present in an amount ranging from 15 to 40% by weight, based on the total weight of the gear oil composition, preferably 25 to 35% by weight based on the total weight of the gear oil composition. 4. A composition according to claim 3 present in an amount. The composition of claim 4, wherein the gear oil composition has a pressure viscosity coefficient of at least 16.5 GPa ⁻¹ at a temperature in the range of 70-100 ° C. The composition of claim 1, wherein the gear oil composition has a traction coefficient of less than 0.028 with a 40 percent slip / roll ratio at 15 mm ² / sec. The composition of claim 6, wherein the gear oil composition has a traction coefficient of less than 0.026 at a 40 percent slip / roll ratio at 15 mm ² / sec.   The composition of claim 1, wherein the gear oil composition has a film thickness selected from the group consisting of at least 175 nm at 80 ° C, at least 160 nm at 90 ° C, or at least 130 nm at 100 ° C. The composition according to claim 1, wherein the PAO base material has a kinematic viscosity at 40 ° C. in the range of 40 to 500 mm ² / sec. The composition according to claim 1, wherein the PAO base material has a kinematic viscosity at 100 ° C. of 10 to 16 mm ² / sec and a viscosity index of 140 to 160. The composition of claim 1, wherein the mineral oil has a kinematic viscosity at 100 ° C. of 2.3 to 3.4 mm ² / sec and a% Cp as defined by ASTM D3238 (R2000) of 70 or more. . The mineral oil has a kinematic viscosity at 40 ° C. of less than 80 mm ² / sec,
A mixture comprising at least a synthetic oil and mineral oil having a kinematic viscosity at 100 ° C. of 3.5 to 7 mm ² / sec and at least a synthetic oil and mineral oil having a kinematic viscosity at 100 ° C. of 20 to 52 mm ² / sec. The composition of claim 1 comprising. Mineral oil, and kinematic viscosity at 40 ° C. of 80 to 120 mm ² / sec, and the kinematic viscosity at 100 ° C. for 10~14mm ² / sec, is neutral Group II base oil having a viscosity index of 80 to 120 The composition of claim 1. A method for improving the traction characteristics of a gear oil composition,
The gear oil composition has a traction coefficient of 0.030 or less at a slip / rolling ratio of 40 percent at 15 mm ² / sec, a temperature range of 70-100 ° C., a load of 20 Newtons, and 1.1 m / sec. A kinematic viscosity at 100 ° C. of 3 to 120 mm ² / sec and a viscosity index of at least 60 so as to have a pressure viscosity coefficient of 15.5 GPa ⁻¹ or more at the rolling speed and a film thickness of more than 175 nm at 80 ° C. A base oil matrix comprising at least a mineral oil having a synergistic range of 5 to 48% by weight, preferably 15 to 40% by weight, more preferably 25 to 35% by weight, based on the total weight of the gear oil composition. Adding at least a quantity of polyalphaolefin (PAO) base stock, wherein the PAO base stock is in the range of 80-110 mm < ² > / sec. The above-mentioned method having a kinematic viscosity at 40 ° C., a kinematic viscosity at 100 ° C. of 10 to 16 mm ² / sec, and a viscosity index of 140 to 160.

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