JP2010521559A - Multifunctional driveline fluid - Google Patents

Abstract

1-20% by weight compound having at least about 0.045 traction coefficient, at least 50% by weight oil of lubricating viscosity, phosphorus compound and 2,5-dimercapto-1,3,4-thiadiazole or derivatives thereof And compositions having a kinematic viscosity at 100 ° C. up to about 12 mm ² / sec are suitable for lubricating the transmission. The present invention provides a method for lubricating a transmission, the method comprising supplying the composition described above to the transmission.

Description

(Background of the Invention)
The present invention relates to a lubricant for a transmission having good lubricating properties and a relatively high traction coefficient.

  Efforts continue in the transmission industry to improve the fuel economy of the automobile in which the transmission is installed. This trend is first manifested in the train car as a result of legislation on fuel economy and is gradually affecting other types of cars (including heavyweight trucks).

  One approach to meeting emissions and performance requirements while improving fuel economy is to use a combination of transmission technologies. For example, a so-called dual clutch transmission incorporates a combination of a manual clutch component and a wet clutch that represents an automatic transmission. Lubricating such transmissions is a challenge because manual transmission fluid technology is not always compatible with wet clutches. The present invention includes an automatic transmission, a manual transmission, an automatic manual transmission, a dual clutch transmission, a traction drive (eg, a toroidal traction drive), a continuously variable transmission (eg, a push belt transmission and a pull-chain transmission), A wide variety of mechanically powered transmission devices, including IVT (infinitely variable transmission), hybrid transmission, and hybrid-powered vehicles, or transmissions for gasoline, diesel, or electric vehicles Providing a fluid which is suitable for lubrication.

  Traction fluids based on various base fluids are known. For example, Patent Document 1 (Tipton, Apr. 16, 2002) describes a polymer of at least one olefin containing 3 to 5 carbon atoms, a hydrocarbon molecule containing a non-aromatic cyclic moiety, or a mixture thereof. Disclosed is a traction fluid formulation comprising a base fluid; a low temperature viscosity control agent (eg, a linear α-olefin polymer or oligomer), and a dispersant and surfactant additive package. Examples include phosphoric acid and dialkyl hydrogen phosphites and alkyl phosphite friction modifiers. The same example also includes dialkyl dimercaptothiadiazole.

  U.S. Patent No. 6,057,028 (Muraki et al., August 27, 1991) discloses a lubricating oil for traction drive, comprising 19 substituted cyclohexane rings linked by methylene groups. Mainly composed of naphthenic hydrocarbons having the number of carbon atoms. Conventional lubricating oil additives (eg, antioxidants, agents to increase viscosity index, rust inhibitors, surfactants, antifoams, etc.) are converted if necessary. Calcium sulfate is disclosed as a surfactant.

  U.S. Patent No. 6,057,028 (Wygant, August 17, 1976) discloses α-alkylstyrene hydrogenation dimers that are useful as tractive fluids. Additives such as VI improvers, antioxidants, antiwear agents, rust inhibitors, dispersants, and dyes can be included.

  U.S. Patent No. 6,099,056 (Duling et al., June 29, 1976) discloses a blended traction fluid comprising a hydrogenated polyolefin and an adamantane ether. The lubricants described can include other oils and additives (eg, sludge dispersants). Particularly useful additives that combine detergency, rust prevention and improved friction at high speed are Mg salts, Ca salts or Ba salts (particularly overbased salts) of certain weak acids.

  Various additive formulations for use in transmission fluids and other functional fluids are generally known. For example, Patent Document 5 (Sumieski et al., January 12, 1999) (equivalent to Patent Document 6 (published June 6, 1996)) describes improved anti-shudder characteristics for automatic transmissions. And compositions for use in lubricants and functional fluids to provide shudder durability properties. The composition comprises a mixture of alkoxylated fatty amines as well as other friction modifiers. Preferred compositions include alkoxylated fatty amines, other friction modifiers, antioxidants, overbased metal organic acids, dispersants, viscosity index improvers and / or dispersant-viscosity modifiers, extreme pressure agents, seal swelling. Agent, and 85% phosphoric acid. Base oils of lubricating viscosity include liquid petroleum oils and paraffinic, naphthenic, or mixed naphthenic-paraffinic type solvent-treated or acid-treated mineral lubricating oils.

  U.S. Patent No. 6,057,028 (Ward et al., June 26, 2001) discloses a lubricating fluid for reduced air entrainment and improved gear protection. The improvement may result from the use of 2,5-dimercapto-1,3,4-thiadiazole and its derivatives together with silicone and / or fluorosilicone antifoam agents. Phosphoric acid may also be present.

  U.S. Patent No. 6,057,049 (Sumieski et al., August 15, 2000) describes a composition comprising a friction modifier for a continuously variable transmission (lubricating oil, shear-stable viscosity modifier, overbased metal. Salt, phosphorus compound, and at least two friction modifiers).

  The present invention therefore lubricates to satisfy one or more of a variety of transmissions, including automatic transmissions, manual transmissions, continuously variable transmissions, dual clutch transmissions, and others mentioned above. The problem of providing a single fluid to be obtained is solved. It is also suitable for use as a hydraulic fluid, final drive oil, hybrid passenger car fluid, and fluids for other power transmission and industrial applications.

US Pat. No. 6,372,696 US Pat. No. 5,043,497 U.S. Pat. No. 3,975,278 US Pat. No. 3,966,624 US Pat. No. 5,858,929 European Patent Application Publication No. 747,464 US Pat. No. 6,251,840 US Pat. No. 6,103,673

(Summary of the Invention)
The present invention provides a lubricating composition suitable for lubricating a transmission, the composition comprising (a) (i) a hydrocarbon comprising a non-aromatic cyclic structure, (ii) a number average molecular weight of 180-600. A polybutene, (iii) an ester having a branched or non-aromatic cyclic alkyl moiety (eg, a branched or non-aromatic cyclic alkyl in its acid moiety or in both the alcohol and acid moieties) A polyol ester having a moiety), and a compound selected from the group consisting of 1 to 20 wt% of a compound having a traction coefficient of at least about 0.045 or at least 0.05; (b) component (a) Oils of at least 50% by weight of a lubricating viscosity other than the above substances; (c) phosphorus compounds (eg phosphorous acid or sublimation) And (d) 2,5-dimercapto-1,3,4-thiadiazole or a derivative thereof, wherein the lubricating composition is up to about 12 mm ² / sec at 100 ° C. Kinematic viscosity.

  The present invention also provides a method for lubricating a transmission, the method comprising supplying a composition as described above to the transmission. The transmission may include a traction drive.

(Detailed description of the invention)
Various preferred features and embodiments are described below by way of non-limiting illustration.

The first component of the lubricating composition of the present invention is a compound (ie, fluid or oil) that can be characterized as a traction fluid. Such fluids exhibit a traction coefficient of at least 0.045 or at least 0.05. Certain such fluids exhibit a traction coefficient of 0.053 or 0.06 (up to 0.12), or 0.08-0.10. The traction coefficient is the ratio of the force transmitted in sliding / rotating contact to the normal or clamping force between the rotating elements.
μ (traction coefficient) = F (tangent) / N (vertical)
Traction factors and various traction fluids are described in great detail in SAE Technical Paper Series 2000-01-2906 (October 16-19, 2000). As used herein, a traction coefficient limit, such as at least 0.05, refers to a measurement at 100 ° C. at 10% sliding / rotation ratio (SRR), a speed of 4 m / s, and 1.25 GPa. .

Certain types of fluids are particularly suitable for use in traction fluids due to their inherently good (high) traction coefficient. Particularly suitable fluid types are (1) hydrocarbon molecules containing non-aromatic cyclic structures, (2) polybutenes with a number average molecular weight of 180-600; and (3) branched or non-aromatic cyclics. Esters having an alkyl moiety (eg, in the acid moiety or in both the alcohol and acid moieties (ie, in the ester moiety corresponding to the constituent alcohol or in the moiety corresponding to the constituent acid), Polyol esters having a cyclic or non-aromatic cyclic alkyl moiety may be used, and mixtures of these types of materials may also be used.For proper performance, the traction fluid component (base fluid) is at 100 ° C. 2.5mm ² / s (cSt) viscosity greater than (ASTM D-445) (e.g., at least 3.0m ² / s (cSt) or 3.5mm ² / s (cSt), ^typically, 12.0mm 2 ^/s(12.0cSt) up or 10.0mm ² / s (cSt) up or 8.0 mm ² / S (cSt) or 6.0 mm ² / s (cSt) at 100 ° C. This component may also have at least 10 carbon atoms, or at least 12 or 15 or 18 carbon atoms. And may contain up to 200 or up to 100 or up to 50 carbon atoms, if desired.

Suitable fluid types (1) include a wide variety of cyclic containing hydrocarbon molecules. Examples of these include di (cyclohexyl) alkanes, cyclohexylhydrindanes and adamantane compounds as described in US Pat. No. 3,966,624; as described in US Pat. No. 4,871,476. Cyclohexanol and esters of cyclohexanecarboxylic acid; decahydronaphthalene (“Decalin” ^™ ), cyclohexyldecahydronaphthalene, substituted as described in US Pat. No. 3,803,037 Decahydronaphthalene, alkyl-substituted cyclohexyldecahydronaphthalene, and mixtures thereof; described in US Pat. No. 5,043,497 Various materials having two cyclohexane rings linked by a methylene group; various hydrocarbon compounds having a bicyclooctane skeleton as described in US Pat. No. 5,422,027; , 126,065, norbornene dimer, trimer or tetramer hydrogenation products; cyclic monoterpenoid monomer hydrogenation dimers, trimers described in US Pat. No. 4,975,215 Or various polymers; various tert-cyclohexyl compounds disclosed in US Pat. No. 5,850,745; perhydrofluorene derivatives disclosed in US Pat. No. 4,774,013; and preferably US Pat. Hydrogenated α-alkyls as described in US Pat. Straight-chain dimer of Ren and the like. Any of the above materials can be used in hydrogenated form to ensure removal of carbon unsaturation; in fact, certain hydrogenated styrene derivatives (or cyclohexane derivatives) are essentially hydrogenated. It is a seed. However, aromatic cyclic structures (eg, those derived from styrene) can also be present in the base fluid. Because aromatic cyclic structures are generally considered less harmful than olefinic unsaturation.

  Of the materials suitable for the fluid option (1), the majority of α-alkylstyrenes are hydrogenated linear dimers. These dimers are said to be largely linear, as opposed to cyclic dimers that exhibit other possible structures. Such materials can be represented by the following general structure:

Here, each R is an alkyl group of 1 to 4 carbon atoms, and C ₆ H ₁₁ represents a cyclohexyl group. Such materials and their preparation are described in detail in US Pat. No. 3,975,278.

  Suitable fluids of type (2) include polymeric isobutylene (particularly those having a number average molecular weight of 180-600, or 200-500). The polymer can be unsaturated to remove any remaining unsaturation. Such materials and their preparation are well known and are described, for example, in US Pat. No. 3,966,624, particularly as Component A described in column 12, line 32 to column 16, line 11. .

  A suitable fluid of type (3) comprises an ester of one or more polymers having 4 to 8 carbon atoms and 2 to 6 OH groups. The acid-derived portion of the ester can have a branched or cyclic structure, and the polyol-derived portion can also have a branched or cyclic structure. Examples of suitable polyols include ethylene glycol, 1,2-propylene glycol and 1,3-propylene glycol, butylene glycol, glycerin, neopentyl glycol, pentaerythritol, 2-methylpropane-1,3-diol, 2- Methylpropane-1,2-diol, 2-methylglycerol, 1,1,1-tris (hydroxymethyl) ethane, cyclohexanediol (1,2 isomer or 1,3 isomer or 1,4 isomer, cis or trans), cyclohexanetriol, tetrol, pentol, and hexol (eg, inositol) and various carbohydrates (eg, fucose, allose, fructose, galactose, glucose, mannose, sorbose, tagatose, Fine talose), and the like. The alcohol functionality of such molecules may be fully esterified or there may be unreacted hydroxy groups.

  The polyol is condensed with one or more acids, the acid may be a cyclic acid or a branched acid and is typically a monocarboxylic acid. Suitable cyclic acids include cyclopentane carboxylic acid, cyclopentyl acetic acid, cyclohexyl acetic acid, cyclohexane carboxylic acid, substituted cyclic acids having an alkyl group with 1 to 8 carbon atoms (eg methyl cyclohexane carboxylic acid And ethylcyclohexanecarboxylic acid). Also included are polycyclic carboxylic acids such as norbornane carboxylic acid, norbornane acetic acid, adamantane carboxylic acid, adamantane acetic acid, decahydronaphthalene carboxylic acid, and various substituted ones of such materials. Examples can be neopentyl glycol cyclohexanecarboxylic acid diesters Suitable branched acids include those having one or more quaternary carbon atoms in the carbon chain. Include 2,2-dimethylbutyric acid and its homologues (eg, 2,2,4,4-tetramethylpentanoic acid and acids containing both branched and cyclic groups (eg, dicyclohexylacetic acid). Suitable linear acids include n-heptanoic acid, n-octanoic acid, n-nonanoic acid nonanaoic acid), n- decanoic acid, and 30 or other acids up to 24 or 18 carbon atoms. Mixtures of such acids may also be used.

  In certain embodiments, the ester has a cyclic group (eg, one or more cyclohexyl groups or substituted cyclohexyl groups) in the acid-derived portion of the ester, or the acid-derived portion and alcohol-derived portion of the ester. It exists in both. These esters and their methods of preparation are described in U.S. Pat. Nos. 4,871,476; 4,886,613; 4,886,614; 4,889,650; 5,075. , 024; and 3,398,165. Suitable esters are commercially available as traction fluid materials.

  The amount of compound having a high traction coefficient is typically 1 to 20% by weight of the lubricating composition, or 5 to 18% by weight or 8 to 12% by weight.

  The lubricating composition also includes at least 30 wt% or at least 50 wt% oil of lubricating viscosity (other than the traction fluid of the above components). The amount of oil of lubricating viscosity (also referred to as base oil) can also be 60-98 wt% or 75-95 wt%.

The base oil used in the lubricating oil composition of the present invention may be selected from any of the base oils in Groups I-V, as specified in the American Petroleum Institute (API) Base Oil Interchangeability Guidelines. The five base oil groups are as follows:
Base oil classification Sulfur (%) Saturation (%) Viscosity index Group I> 0.03 and / or <90 80-120
Group II <0.03 and> 90 80-120
Group III <0.03 and>90> 120
Group IV All poly alpha olefins (PAO)
Group V All others not included in any of Group I, II, III, or IV

Groups I, II and III are mineral oil based stocks. The oil of lubricating viscosity can then include natural or synthetic lubricating oils and mixtures thereof. Mixtures of mineral and synthetic oils (especially polyalphaolefin oils and polyester oils) are often used.

  Natural oils include animal and vegetable oils (eg, castor oil, lard oil, and other vegetable acid esters), and mineral lubricating oils (eg, liquid paraffin oil, and solvent or acid treated, Paraffinic, naphthenic or mixed paraffinic-naphthenic type mineral lubricants). Hydrotreated or hydrocracked oils fall within the scope of useful oils of lubricating viscosity.

  Oils of lubricating viscosity derived from coal or shale are also useful. Synthetic lubricating oils include hydrocarbon oils and halo-substituted hydrocarbon oils (eg, polymerized and copolymerized olefins and mixtures thereof), alkylbenzenes, polyphenyls (eg, biphenyl, terphenyl, and alkylated poly). Phenyl), alkylated diphenyl ethers and alkylated phenyl sulfides and their derivatives, analogs, and homologs.

  Alkylene oxide polymers and their internal polymers and derivatives, and those in which the terminal hydroxyl groups have been modified, for example by esterification or etherification, constitute another class of known synthetic lubricating oils that can be used.

Synthetic lubricating oils Another suitable class that may be used include those or polyol ether is prepared from monocarboxylic acids and polyols esters of dicarboxylic acids and C ₅ -C _12.

  Other synthetic lubricating oils include liquid esters of phosphorus-containing acids, polymeric tetrahydrofurans, silicon-based oils (eg, poly-alkyl, polyaryl, polyalkoxy-, or polyaryloxy-siloxane oils, and silicate oils). .

  Hydrotreated naphthenic oils are also known and can be used, as can oils prepared by the Fischer-Tropsch GTL (Fischer-Tropsch gas-to-liquid) synthesis procedure.

  Unrefined oils, refined oils and rerefined oils (either natural or synthetic) (and mixtures of any two or more thereof) of the type disclosed herein above are compositions of the present invention. Can be used in objects. Unrefined oils are those obtained directly from natural or synthetic sources without further purification. Refined oils are similar to unrefined oils except that they have been further processed in one or more refining steps to improve one or more properties. Rerefined oils are obtained by a process similar to that used to obtain refined oils applied to refined oils that have already been used. Such rerefined oils are often further processed by techniques related to the removal of spent additives and products from which the oil has decomposed.

In certain embodiments of the invention, the base oil is a poly-alpha olefin such as a synthetic oil (eg, a 4 centistoke poly alpha olefin (ie, having a nominal viscosity of 4 mm ² / sec at 100 ° C.)). (Typically hydrogenated)). In certain embodiments, a mixture of synthetic and mineral base oils is used. In certain embodiments, at least 50 wt%, or at least 80 wt%, or at least 90 wt% of the oil of lubricating viscosity is a synthetic oil.

Another optional or representative component of the lubricating composition of the present invention is a phosphorus compound (typically phosphorous acid or a phosphite or salt thereof (ie, a salt of phosphorous acid or a phosphite) These may include phosphorous acid, phosphites, phosphites, or mixtures thereof, wherein the phosphites or esters are of the formula (R ¹ X) (R ² X) P (X) _n X _m R ³ or a salt thereof, wherein each X is independently an oxygen atom or a sulfur atom, n is 0 or 1, and m is 0 or 1. And m + n is 1 or 2, and R ¹ , R ² , and R ³ are hydrogen or a hyhydrocarbyl group, and in one embodiment at least one of R ¹ , R ² , or R ³ One This component is therefore comprised of organic or inorganic phosphorous and phosphoric acids, thiophosphorous and thiophosphoric acids, and phosphites, phosphate esters, thiophosphites, and thiophosphorus Suitable salts include metal salts or amine salts of phosphites, and amine salts of phosphites (eg, phosphorous acid and amine-containing dispersants (eg, succinimide dispersants)). Certain of these phosphorus materials may exist in tautomeric forms, and all such tautomers are encompassed by the above formula and are present in the present invention. It is noted that it is intended to be included within the scope of the invention, for example phosphorous acid and certain phosphite esters are Rarely change I, it can be shown in at least two ways:

Each of these structures is intended to be encompassed by the present invention.

  The phosphorus-containing acid can be at least one phosphate, phosphonate, phosphinate or phosphine oxide. These pentavalent phosphorus derivatives can be represented by the following formula:

Here, R ¹ , R ² and R ³ are as defined above. The phosphorus-containing acid can be at least one phosphite, phosphonite, phosphinite or phosphine. Examples of trivalent phosphorus derivatives can be represented by the following formula:

Here, R ¹ , R ² and R ³ are as defined above. In general, the total number of carbon atoms in R ¹ , R ² and R ³ is at least 8, and in one embodiment at least 12, and in one embodiment at least 16. Examples of useful R ¹ , R ² and R ³ groups include hydrogen, t-butyl, isobutyl, amyl, isooctyl, decyl, dodecyl, oleyl, C18 alkyl, eicosyl, 2-pentenyl, dodecenyl, phenyl, naphthyl, alkyl Examples include phenyl, alkyl naphthyl, phenylalkyl, naphthylalkyl, alkylphenylalkyl, and alkylnaphthylalkyl groups.

  In another embodiment, the phosphorous acid or ester comprises at least one direct carbon and phosphorus (eg, those prepared by treatment of olefin polymers (eg, phosphorylating agents (eg, phosphorus trichloride, seven Linkage of one or more of the above polyalkenes (eg, polyisobutene having a molecular weight of 1000) with phosphorus sulfide, phosphorus pentasulfide, phosphorus trichloride and sulfur, white phosphorus and sulfur halide or phosphorothioic chloride Characterized by the linkage of

In certain embodiments, at least two of the X atoms in the structure are oxygen. As a result, the structure ^{is (R 1 O) (R 2} O) P (X) n X m R 3 or ^{(R 1 O) (R 2} O) P (X) n X m H. This structure can correspond to phosphoric acid, for example, when R ¹ , R ² and R ³ are hydrogen. Phosphoric acid as acid itself, H ₃ PO ₄ and other equivalent forms (eg pyrophosphoric acid and phosphoric anhydride (including 85% phosphoric acid (aqueous), which is generally a commercially available grade material)) Exists. The above formulas also indicate that when one or both of R ¹ and R ² are each alkyl and R ³ is hydrogen, monoalkyl hydrogen phosphite or dialkyl hydrogen phosphite (eg, hydrogen phosphite Dibutyl (phosphite), or when R ¹ , R ² and R ³ are each alkyl can correspond to trialkyl phosphite; in each case n is 0 and m is 1 In some cases, the remaining X is O. The structure corresponds to phosphoric acid or related materials when n and m are each 1; for example, one of the X atoms is sulfur and the R When one, two, or three of the groups are each alkyl, a phosphate ester (eg, monoalkyl monothiophosphate, monoalkyl dithiophosphate, or trithiolyl) Monoalkyl acid).

  Phosphoric acid and phosphorous acid are well known commercial items. Thiophosphoric acid and thiophosphorous acid are likewise well known and are prepared by reaction of phosphorus compounds with elemental sulfur from other sulfur sources. The process for preparing thiophosphorous acid is described in Organic Phosphorus Compounds, Vol. 5, pages 110-111, G.M. M.M. It is reported in detail in Kosolapoff et al., 1973.

  The salts of phosphorous acid are well known. Salts include ammonium and amine salts and metal salts. Zinc salts (eg, zinc dialkyldithiophosphates and zinc dialkylphosphates) are well known and useful in certain applications. In certain embodiments, the salt can be a dihydrocarbyl dithiophosphate metal salt or dihydrocarbyl dithiophosphate amine salt or a monohydrocarbyl phosphate metal salt or amine salt and a dihydrocarbyl phosphate metal salt or amine salt.

  Accordingly, the phosphorus compound can be any of the phosphorous acid, dialkyl hydrogen phosphite, metal dihydrocarbyl dithiophosphate, metal dihydrocarbyl phosphate, and mixtures thereof. The amount of the phosphorus compound provides 0.03 to 0.1% by weight phosphorus to the composition, or in other embodiments, 0.04 to 0.09% by weight or 0.05. It can be in an amount suitable to provide ˜0.08 wt% or 0.05 to 0.06 wt% phosphorus. The required amount of a particular target phosphorus compound can be readily calculated by one skilled in the art.

  The lubricating composition of the present invention further comprises 2,5-dimercapto-1,3,4-thiadiazole or a derivative thereof, partly functioning as a rust inhibitor. Examples of suitable dimercaptothiadiazoles include 2,5-dimercapto-1,3,4-thiadiazole, hydrocarbyl-substituted 2,5-dimercapto-1,3,4-thiadiazole, and hydrocarbylthio-substituted 2, Examples include 5-dimercapto-1,3,4-thiadiazole. In some embodiments, the number of carbon atoms on the hydrocarbyl substituent can be 1-30, 2-25, 4-20, or 6-16. More specific examples include 2,5-bis (tert-octyldithio) -1,3,4-thiadiazole, 2,5-bis (tert-nonyldithio) -1,3,4-thiadiazole, 2,5 -Bis (tert-decyldithio) -1,3,4-thiadiazole, 2,5-bis (tert-undecyldithio) -1,3,4-thiadiazole, 2,5-bis (tert-dodecyldithio) -1,3 , 4-thiadiazole, 2,5-bis (tert-tridecyldithio) -1,3,4-thiadiazole, 2,5-bis (tert-tetradecyldithio) -1,3,4-thiadiazole, 2,5-bis (Tert-pentadecyldithio) -1,3,4-thiadiazole, 2,5-bis (tert-hexadecyldithio) -1,3,4-thiadiazole 2,5-bis (tert-heptadecyldithio) -1,3,4-thiadiazole, 2,5-bis (tert-octadecyldithio) -1,3,4-thiadiazole, 2,5-bis (tert-nonadecyldithio) ) -1,3,4-thiadiazole and 2,5-bis (tert-eicosyldithio) -1,3,4-thiadiazole. Furthermore, the dimercaptothiadiazole or a derivative thereof can be provided by a combination or reaction product of an oil-soluble dispersant and dimercaptothiadiazole as described below. Such treated dispersants (eg, treated succinimide dispersant s) and their preparation are known and are described in US Pat. No. 4,136,043 (column 9, lines 18-36, column 10). Line 47 to column 11 line 25 and Examples 26-35).

  In one embodiment, the dimercaptothiadiazole of the present invention is 0.05 to 4.0 wt% or 0.05 to 2.0 wt%, or 0.1 to 1.5 wt% of the lubricating composition, or It can be present in an amount of about 0.15 to 1.0% by weight. In certain embodiments, the 2,5-dimercapto-1,3,4-thiadiazole or derivative thereof is 0.005 to 1 wt%, or 0.01 wt% to 0.5 wt%, relative to the composition. % Sulfur may be present in an amount providing sulfur.

  Each of the compositions or additives as listed herein can be mixed into the final lubricating composition. Alternatively, any one or more of them can be supplied as a concentrate in oil. For example, the phosphorus compound and the thiadiazole compound, and the additional optional ingredients described below, can be prepared with a relatively small amount of diluent (typically an oil). If desired, some or all of the components having the specified traction coefficient may also be included in the concentrate, and any such concentrate may contain a large amount of oil or oil plus traction component. , Optionally, can be blended to provide the final lubricating composition. The traction component itself can act as a diluent for the concentrate. When oils of lubricating viscosity are used as diluents, the amount of oil in such concentrates can be, for example, 20-50% by weight or 30-50% by weight, and the amount of other ingredients is Corresponding increase.

  Accordingly, the lubricating composition of the present invention may also include additional additives such as at least one dispersant, or at least one surfactant, or a mixture thereof. Dispersants and surfactants are very well known and are commonly used materials in the lubrication field.

  Surfactants are typically overbased materials (otherwise referred to as overbased salts or overbased salts) generally in combination with the metal and the specific metal that has reacted with the metal. According to the stoichiometry of acidic organic compounds, it is a single-phase, homogeneous Newtonian system characterized by the excess metal content present for neutralization. The overbasing substance includes an acidic substance (typically an inorganic acid or a lower carboxylic acid, preferably carbon dioxide), an acidic organic compound, and at least one inert organic solvent (mineral oil) for the acidic organic substance. , Naphtha, toluene, xylene, etc.), and a mixture containing a stoichiometric excess of a metal base and a cocatalyst (eg, phenol or alcohol). The acidic organic material typically has a sufficient number of carbon atoms to provide a degree of solubility in the oil. The amount of excess metal is generally expressed in terms of metal ratio. The term “metal ratio” is the ratio of the total equivalent of the metal to the equivalent of the acidic organic compound. Neutral metal salts have a metal ratio of 1. A salt having as much as 4.5 times the metal present in a normal salt has 3.5 equivalents of excess metal, ie, has a ratio of 4.5.

  Such overbased materials are well known to those skilled in the art. Patents describing techniques for making basic salts of sulfonic acids, carboxylic acids, phenols, phosphonic acids, and mixtures of two or more thereof include US Pat. No. 2,501,731; No. 2,616,905; No. 2,616,911; No. 2,616,925; No. 2,777,874; No. 3,256,186; No. 3,384,585 No. 3,365,396; No. 3,320,162; No. 3,318,809; No. 3,488,284; and No. 3,629,109 .

Other overbased materials include salixarate surfactants. These include overbasing materials prepared from salicylic acid (which may be unsubstituted) and hydrocarbyl-substituted phenols, and such entities may contain —CH ₂ — or other alkylene bridges. Connected through. Although the above salixarate derivatives are thought to have a predominantly linear structure rather than a macrocyclic structure, both structures are intended to be encompassed by the term “salixarate”. Salixarate derivatives and methods for their preparation are described in more detail in US Pat. No. 6,200,936 and PCT Publication WO 01/56968.

  The amount of the surfactant in the lubricating composition of the present invention, if present, can be 1-10 wt%, or 1.5-7 wt%, or 2-3 wt%.

  Dispersants are well known in the field of lubricants, and include mainly those known as ashless type dispersants and polymer dispersants. Ashless type dispersants are characterized by polar groups attached to relatively high molecular weight hydrocarbon chains. Exemplary ashless dispersants include N-substituted long chain alkenyl succinimides having various chemical structures and typically include:

Where each R ¹ is independently an alkyl group, frequently a polyisobutylene group having a molecular weight of 500 to 5000, and R ² is an alkylene group, generally ethylene (C ₂ H ₄ ) Group. Such molecules are generally obtained from the reaction of alkenyl acylating agents with polyamines, and a wide variety of linkages between the two moieties are possible besides the simple imide structure shown above. And various amides and quaternary ammonium salts. Moreover, various connection modes of the R ¹ group on the imide structure are conceivable, and various cyclic connections are mentioned. Succinimide dispersants are described in more detail in US Pat. Nos. 4,234,435 and 3,172,892 and in EP 0355895.

  Another class of ashless dispersant is high molecular weight esters. These materials are those listed above except that they can be seen as prepared by reaction of a hydrocarbyl acylating agent with a polyhydric aliphatic alcohol (eg, glycerol, pentaerythritol, or sorbitol). It is similar to succinimide. Such materials are described in more detail in US Pat. No. 3,381,022.

  Another class of ashless dispersant is Mannich bases. These are materials formed by condensation of higher molecular weight, alkyl-substituted phenols, alkylene polyamines, and aldehydes (eg, formaldehyde). Such materials can have the following general structure:

(Including various isomers) and are described in more detail in US Pat. No. 3,634,515.

  Other dispersants include polymeric dispersant additives, which are generally hydrocarbon-based polymers that contain polar groups to impart dispersibility properties to the polymer.

  The dispersant can also be post-treated by reaction with any of a variety of agents. Among these are urea, thiourea, dimercaptothiadiazole, carbon disulfide, aldehydes, ketones, carboxylic acids, hydrocarbon-substituted succinic anhydrides, nitriles, epoxides, boron compounds, and phosphorus compounds. References detailing such treatment are listed in US Pat. No. 4,654,403.

  The amount of the dispersant in the lubricating composition of the present invention can be 1 to 10 wt%, or 1.5 to 7 wt%, or 2-3 wt%, if necessary.

  The compositions of the present invention may also include a viscosity index modifier, for example, in limited amounts (ie, up to 10% by weight of the composition). In certain embodiments, the amount of this component is 0-1% by weight, and in one embodiment, the traction fluid is substantially free of polymer viscosity index modifier (ie, less than 1% or 0 Less than 1%).

  Polymer viscosity index modifiers (VMs) are very well known in the art and most are commercially available. Hydrocarbon VMs include polybutenes, poly (ethylene / propylene) copolymers, and hydrogenated polymers of styrene and butadiene or isoprene. Esters VM include styrene / maleic anhydride polymer esters, styrene / maleic anhydride / acrylate terpolymer esters and polymethacrylates. The acrylates are commercially available from RohMax and The Lubrizol Corporation; polybutenes are commercially available from Afton Corporation and Lubrizol; ethylene / propylene copolymers are commercially available from ExxonMobil and Afton; hydrogenated polystyrene / isoprene polymers are commercially available from Shell; Styrene / maleic esters are commercially available from Lubrizol and hydrogenated styrene / butadiene polymers are commercially available from BASF.

  Suitable VMs include acrylate-containing or methacrylate-containing copolymers, or copolymers of styrene and unsaturated carboxylic acid esters (eg, esterification of styrene / maleic esters (typically styrene / maleic anhydride copolymers). Preferably, the viscosity modifier is a polymethacrylate viscosity modifier, which is prepared from a mixture of methacrylate monomers having various alkyl groups. The group can be either a straight chain or branched group containing 1 to 18 carbon atoms.If a small amount of nitrogen-containing monomer is copolymerized with the alkyl methacrylate, the dispersion properties also depend on the product. Therefore, such a product Such products are referred to in the art as dispersant-type viscosity modifiers or simply dispersant-viscosity modifiers. N-vinylpyrrolidone and N, N′-dimethylaminoethyl methacrylate are examples of nitrogen-containing monomers Polyacrylates prepared from the polymerization or copolymerization of one or more alkyl acrylates are also used as viscosity modifiers. Useful It is preferred that the viscosity modifier of the present invention is a dispersive viscosity modifier.

  When the viscosity modifier component comprises polyisobutene, this component is distinguished from the material indicated as having a traction coefficient of at least 0.045 or 0.05 based on its high molecular weight. The traction fluid component has a relatively low molecular weight (e.g., 180-600), while the polybutene viscosity modifier component, if present, has a high molecular weight, or alternatively, as described below. And a molecular weight of 800 to 6000, 1000 to 3600, or 1200 to 2400. Nevertheless, the polybutene viscosity modifier component can impart some improved traction properties to the composition.

  The above polymers generally have 1,000 to 500,000, or 2,000 to 500,000, or 10,000 to 500,000 (eg, 30,000 to 250,000, or 20,000). ~ 100,000) weight average molecular weight

And polydispersity values of 1.2-5

Can have.

  Another optional material that may be presented in the present invention is one or more friction modifiers. Friction modifiers include alkoxylated fatty amines, borated fatty epoxides, fatty phosphites, fatty epoxides, fatty amines, borated alkoxylated fatty amines, fatty acid metal salts, fatty acid amides, glycerol esters, borated glycerol Esters and fatty imidazolines are mentioned. The amount of friction modifier, if present, can be 0.01-2%, or 0.05-1.2%, or 0.1-1% by weight of the fluid composition.

  Other conventional ingredients such as antioxidants, seal swelling agents, rust inhibitors, antifoams, and pigments can be present in conventional amounts.

  In certain embodiments, molybdenum-containing additives (eg, molybdenum dithiocarbamate) and titanium-containing additives may also be present to impart desirable properties (eg, wear resistance, antioxidant properties, and friction modification). .

The lubricating composition thus prepared should have a kinematic viscosity at 100 ° C. up to about 12 mm ² / sec (eg ² to 10 mm ² / sec or 6 to 8 mm ² / sec). Obtaining a lubricant with such a viscosity is within the skill of one of ordinary skill in the art by the choice of base stock and other components having the appropriate viscosity.

  It is known that some of the above materials can interact in the final formulation so that the components of the final formulation can be different from those initially added. For example, metal ions (eg, surfactant metal ions) can migrate to other acidic or anionic sites of other molecules. Products formed thereby (including products formed when the composition of the invention is used in its intended application) may not be plainly described. Nevertheless, all such modifications and reaction products are included within the scope of the present invention; the present invention encompasses compositions prepared by admixing the components described above.

As used herein, the term “hydrocarbyl substituent” or “hydrocarbyl group” is used in its ordinary sense, which is well known to those skilled in the art. Specifically, this term refers to a group having a carbon atom directly bonded to the rest of the molecule and having predominantly hydrocarbon character. Examples of hydrocarbyl groups include the following:
Hydrocarbon substituents (eg, aliphatic (eg, alkyl or alkenyl), alicyclic (eg, cycloalkyl, cycloalkenyl) substituents, and substituted with aromatic, substituted with aliphatic, and An alicyclic substituted aromatic substituent, as well as a cyclic substituent, wherein the ring is complete via another part of the molecule (eg, two substituents together To form a ring);
Substituted hydrocarbon substituents (ie, in the context of the present invention, substituents including non-hydrocarbon groups that do not change the predominantly hydrocarbon nature of the substituents (eg, halo (particularly chloro and fluoro), Hydroxy, alkoxy, mercapto, alkylmercapto, nitro, nitroso, and sulfoxy);
Hetero substituents (ie, those having predominantly hydrocarbon character while in the context of the present invention include other than carbon in the ring or chain (alternatively consisting of carbon atoms) And includes substituents such as pyridyl, furyl, thienyl and imidazolyl). Heteroatoms include sulfur, oxygen and nitrogen. In general, as few as 2 and preferably as few as 1 non-hydrocarbon substituent will be present for every 10 carbon atoms in the hydrocarbyl group; typically there will be no non-hydrocarbon substituent in the hydrocarbyl group .

  Examples 1-3. The lubricating composition is prepared as shown in Table I and has a kinematic viscosity as shown below at 100 ° C.

The material designated PAO is a commercially available poly-alpha olefin-based fluid (oil of lubricating viscosity) having a nominal kinematic viscosity at 100 ° C. of 4 mm ² / s. The synthetic esters are 3,5,5-trimethylhexanoic acid (70%), n-heptanoic acid (15%) and n-C8-10 acids (15%) (trade names Solest 68 NA ^TM or Hatcol 3368 ^TM Pentaerythritol (technical grade) ester prepared in The hydrogenated dimer is a hydrogenated linear α-methylstyrene dimer (commercially available under the trade name Santotrac 20 ^™ ). The isobutene oligomer is a hydrogenated oligomer of isobutene (M _n 300-350) (commercially available under the trade name Panalane ^™ ). The PMA VM is a commercially available polymethacrylate viscosity modifier, and the polybutene is a further viscosity modifying additive having approximately the indicated molecular weight (much greater than that of the isobutene oligomer). The additive package consists of a dialkyl hydrogen phosphite antiwear / friction modifier and 2,5-bis (t-nonyldithio) -1,3,4-thiadiazole (dimercaptothiadiazole) and a small amount (0.5% (Including 49% diluent oil)) succinimide dispersant, which has been treated with about 6% dimercaptothiadiazole. The additive package also includes a borated succinimide dispersant, an aromatic amine antioxidant, an overbased calcium surfactant, a seal swelling agent, a rust inhibitor, an antifoam agent, and additional diluent oil.

  Certain of the above examples are tested for traction factor (results reported at 100 ° C., 10% SRR) and wear test. The wear test is the FZG stage load test A10 / 16.6R / 120, which is a 10 mm wide “operated in the reverse direction (wheel drive) at 16.6 m / s pitch linear velocity and a starting temperature of 120 ° C. A ”Use profile test gear. The above test measures the sliding load capacity of the lubricant. The lubricant is tested at increasing torque levels (load phase) until failure criteria are encountered. This is known as a failure load stage; the immediately preceding passing stage is reported as the passing stage. The larger the number, the better the performance (reproducibility is typically ± 1 level). The results of these tests are shown in Table II. Each of the fluids shows good performance.

Each of the documents referred to above is incorporated herein by reference. All numerical values in this description, which specify quantities such as substances, reaction conditions, molecular weight, number of carbon atoms, etc., are modified by the term “about” except in the examples or where explicitly indicated otherwise. Should be understood. Unless otherwise indicated, each chemical or composition referred to herein is a commercially available grade material that is present in isomers, by-products, derivatives, and the above commercially available grades. It should be construed as including other such materials as would normally be understood. However, the amount of each chemical component is indicated except for any solvent or diluent oil, which can be customarily present in commercially available materials unless otherwise indicated. It is to be understood that the upper and lower amounts, ranges, and ratio limits described herein can be combined independently. Similarly, the ranges and amounts for each element of the invention can be used together with ranges and amounts for any of the other elements. As used herein, the expression “consisting essentially of” permits the inclusion of substances that do not inherently affect the basic and novel characteristics of the composition under consideration.

Claims (15)

A lubricating composition suitable for lubricating a transmission, the composition comprising:
(A) (i) a hydrocarbon containing a non-aromatic cyclic structure, (ii) a polybutene having a number average molecular weight of about 180 to about 600, (iii) an ester having a branched or non-aromatic cyclic alkyl moiety, And about 1 to about 20% by weight of a compound having a traction coefficient of at least about 0.045, selected from the group consisting of and mixtures thereof;
(B) at least about 50% by weight of an oil of lubricating viscosity other than the material of component (a);
(C) phosphorous acid or phosphite or a salt thereof; and (d) 2,5-dimercapto-1,3,4-thiadiazole or a derivative thereof,
The lubricating composition has a kinematic viscosity at 100 ° C. up to about 12 mm ² / sec. The composition of claim 1, wherein the compound having a traction coefficient of at least about 0.045 is a substance having a traction coefficient of about 0.05 to about 0.12. 3. The ester molecule (a) (iii) comprises a polyol ester having a branched or non-aromatic cyclic alkyl moiety in its acid moiety or in both alcohol and acid moieties. A composition according to 1. 4. The composition of any one of claims 1-3, wherein the compound having a traction coefficient of at least about 0.045 comprises a pentaerythritol ester. 5. The composition of any one of claims 1-4, wherein the amount of the compound having a traction coefficient of at least about 0.045 is from about 5 to about 18% by weight. The composition according to claim 1, wherein the oil of lubricating viscosity includes a synthetic oil. 7. A composition according to any preceding claim, wherein at least about 50% by weight of the oil of lubricating viscosity is a synthetic oil. The composition according to claim 6 or 7, wherein the synthetic oil is a poly-α-olefin. The phosphorous acid or phosphite or phosphite salt is phosphorous acid, dialkyl hydrogen phosphite, metal salt or amine salt of dihydrocarbyl dithiophosphate, metal salt of monohydrocarbyl phosphate and dihydrocarbyl phosphate or The composition according to any one of claims 1 to 8, which is selected from the group consisting of amine salts and mixtures thereof. 10. The phosphorous acid or phosphite or phosphite salt is present in an amount that provides about 0.03 to about 0.1 weight percent phosphorus to the composition. The composition of any one of these. 11. The composition of any one of claims 1-10, wherein the 2,5-dimercapto-1,3,4-thiadiazole or derivative thereof is present in an amount of about 0.05 to about 4% by weight. The 2,5-dimercapto-1,3,4-thiadiazole or derivative thereof is present in an amount that provides from about 0.005 to about 1 weight percent sulfur to the composition. The composition according to any one of the above. The composition according to claim 1, further comprising a viscosity index modifier. A composition prepared by mixing the ingredients of any one of claims 1-13. 15. A method for lubricating a transmission comprising the step of supplying a composition according to any one of claims 1-14.