EP1233054A1 - Automatic transmission fluids with improved anti-shudder properties - Google Patents

Abstract

Automatic transmission fluids are described which contain at least 0,1wt% of ametal-containing detergent, a dispersant, and a mixture of friction modifiers. Thetransmission fluids according to the present invention exhibit excellent initial antishudder properties, excellent anti-shudder durability, and excellent friction durability.

Description

CROSS REFERENCE TO RELATED APPLICATIONS
• There are no related applications.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
• This research was not sponsored by any entity of the Federal Government.
BACKGROUND OF THEINVENTION1. Field of the Invention
• This invention relates to oil-based automatic transmission fluid compositionshaving excellent slip-stick characteristics, anti-shudder performance, and frictiondurability. More specifically, a preferred aspect of the invention relates to a use of theautomatic transmission fluid in electronically controlled converter clutch (ECCC)applications.
2. Description of the Prior Art
• US Patent 5,578,236, to Ethyl Corporation discloses a power transmission fluidwith enhanced performance characteristics. The power transmission fluid compositiondisclosed therein has, inter alia, an oil-soluble boron content of about 0.001 to about0.1%, an oil soluble phosphorus content of about 0.005 to about 0.2%, and an oil solublemetal additive content of from 0 to about 100 ppm.
• The composition of the '236 patent comprises at least about 50 weight %hydrotreated mineral oils in the range of about 55N to about 125N, about 5 to 40 wt% of hydrogenated poly alpha olefin oligomer having a viscosity of about 2 to about 6 cSt at100 ° C, about 5 to about 20 wt % of an acrylic viscosity index improver, a seal swellagent, an ashless dispersant, an oil soluble friction modifier, and an inhibitor selectedfrom foam, copper corrosion (including thiadiazoles), rust, and oxidation inhibitors.The finished composition has a Brookfield viscosity of 13,000 cP or less at - 40 ° C, anASTM D-4683 viscosity of at least 2.6 mPa.s at 150 ° C, and a viscosity of at least 6.8 cStat 100° C after 40 cycles in the FISST of ASTM D-5275. However, the compositionsdisclosed are preferably devoid of sulfurized components.
• US Patent 5,441,656, also to Ethyl Corporation, discloses an automatictransmission fluid for overcoming shudder problems in continuous slip torqueconverter clutches in automatic transmissions. The automatic transmission fluid("ATF") of the '656 patent includes, among other restrictions, a friction modifier contentwhich contains an N-aliphatic hydrocarbyl substituted diethanolamine in which the N-aliphatichydrocarbyl substituent having in the range of about 14 to about 40 carbonatoms, and an N-aliphatic hydrocarbyl substituted trimethylene diamine in which theN-aliphatic hydrocarbyl substituent is at least one straight chain aliphatic hydrocarbylgroup having in the range of about 14 to about 20 carbon atoms. Conventional coppercorrosion inhibitors (including thiadiazoles) and other optional (e.g. lubricity, dye, pourpoint depressant, etc.) components may be present.
• U.S. Patent Nos. 5,344,579; 5,372,735; and 5,578,236 disclose automatictransmission fluid compositions which exhibit good anti-shudder properties.
• Other U.S. Patents which disclose various automatic transmission fluids include4,795,583; 4,855,074; 4,857,214; 5,089,156; 5,126,064; 5,164,103; 5,171,466; 5,198,133;5,256,324; 5,360,562; 5,387,346; 5,387,352; 5,389,273; 5,439,606; 5,505,868; 5,652,201;5,703,023; 5,817,605; 5,851,962; 5,891,786; and 5,972,851. Each of the above isincorporated by reference.
• These references; however, fail to teach or suggest the combination ofcomponents of the present invention, including the combination of at least 0.10 wt % ofa metal-containing detergent, a dispersant, and a friction modifier system including amixture of at least two different friction modifiers. A preferred mixture of frictionmodifiers is a mixture of an ethoxylated amine and an imidazoline. Such a combinationgives a friction durability of at least 200 hours as measured by the low speed ECCCfriction durability test. It also gives a good balance of torque capacity, durability, initialshudder free performance (during a break in period) and continues to have a robustanti shudder durability over the lifetime of the fluid.
• Commercially, it is known to add various additive packages to automatictransmission fluid, including, among other things, extreme pressure agents, antiwearagents, antioxidant systems, corrosion inhibitor systems, metal deactivators, anti-rustagents, friction modifiers, dispersants, detergents, anti-foam agents, and viscosity indeximprovers. However, not all additives interact predictably or well with one another.
BRIEF SUMMARY OF THE INVENTION
• The present invention relates to the improvement of friction durability, anti-shudderperformance, and slip-stick performance by the inclusion into a finalformulated automatic transmission fluid of a metal-containing detergent, a dispersant,and a friction modifier system including an ethoxylated amine and an imidazoline.
• Other optional components, e.g. anti-rust agents, corrosion inhibitors, additionalfriction modifiers, antioxidants, anti foam agents, extreme pressure agents, additionaldispersants or detergents, and viscosity index improvers, may also be included. Thefully formulated transmission fluid composition provides enhanced performance,especially for ECCC automatic transmissions
BRIEF DESCRIPTION OF THE DRAWINGS
• Figure 1 is a graphical illustration of the friction durability of a composition(Example 3) according to the present invention measured by coefficient of friction andspeed.
• Figure 2 is a graphical illustration of the friction durability of a compositionaccording to the present invention (Example 3) measured by ratio of coefficients offriction and time.
• Figure 3 is a graphical illustration of the extended duration plate clutch frictiontest results of a composition according to the present invention (Example 3) comparedwith two compositions not of the invention (Examples 1 and 2).
• Figure 4 is a graphical illustration of the initial shudder durability of acomposition according to the present invention (Example 3) and two comparativeexamples not of the invention (Examples 1 and 2).
• Figure 5 is a graphical representation of the ECCC friction durability of acomparative example (Example 2), measured by hours to negative slope.
• Figure 6 is a graphical representation of an ECCC friction durability test,measured by coefficient of friction against speed, for an example not of the presentinvention (Example 2).
DETAILED DESCRIPTION OF THE INVENTION
• Vehicles meeting the stringent demands of consumers today require durabilityand performance in all of the vehicular systems. One of the most important systems isthe power transmission system ("transmission") which transmits the power generatedby the automobile engine to the wheels. It being one of the most complex systems inthe vehicle, it is also one of the most costly to diagnose, repair, or replace. Thetransmission usually includes, inter alia, a clutch with plates, a torque converter, and aplurality of gears to alter the power delivered to the wheels by changing the gear ratio.It may also include a wet clutch.
• Discriminating consumers primarily desire high performance, low maintenance(high mileage between servicing), and extended life expectancy. However, with theadvent of new transmission technologies, old standards of performance which werepreviously met with approval are now becoming unacceptable.
• For example, there is worldwide activity by the automobile manufacturers todevelop automatic transmissions incorporating various electronically controlledconverter clutch (ECCC) designs. These developments are being driven by theanticipated increase in Corporate Average Fuel Economy (CAFE) requirements in theU.S.A. The ECCC design allows increases in fuel economy to be gained.
• The advent of ECCC transmissions as well as vehicles equipped with acontinuously variable transmission (CVT) and advances in aerodynamic body designresult in passenger cars with smaller transmissions which tend to operate with higherenergy densities and higher operating temperatures. Such changes have challengedlubricant suppliers to formulate automatic transmission fluids with new and uniqueperformance characteristics including higher torque capacity and friction durability.
• As a result, many original equipment manufacturers (OEMs) are looking forautomatic transmission fluids with frictional characteristics capable of meeting orexceeding the requirements of ECCC, CVT, and other designs while retaining sufficientanti-wear, anti-shudder, and friction durability performance.
• A need exists for an effective way of increasing the friction durability, and hencethe service life, of automatic transmission fluids, especially to meet the needs of vehicleswith the new ECCC or CVT transmissions.
• This invention thus provides an automatic transmission fluid that exhibitsexcellent initial anti shudder performance, anti-shudder durability, and frictiondurability.
• This invention also provides an automatic transmission fluid capable of passingthe GM 3T40 Plate Friction and the DaimlerChrysler Friction Durability test.
• The metal-containing detergent includes, by way of example, calcium-containingdetergents such as calcium sulfonates,, the dispersant includes by way of examplesuccinimide-type dispersants, which may be boronated or phosphorylated, and thefriction modifier system includes, also by way of example, an ethoxylated amine and animidazoline.
• In one embodiment, the fluids of the present invention are used in formulatingautomatic transmission fluids which exhibit good frictional characteristics. In anotherembodiment, the fluids of the present invention are used in formulating automatictransmission fluids which exhibit excellent initial anti-shudder performance, andoutstanding friction durability in the ECCC Friction durability test, as measured by thelowspeed SAE#2 friction rig.
• As is well known in the art, the friction durability of an ATF is assessed throughthe use of anSAE #2 friction test machine. This machine simulates the high-speedengagement of a clutch by using the clutch as a brake, thereby absorbing a specifiedamount of energy. The energy of the system is chosen to be equivalent to the energyabsorbed by the clutch in completing one shift in the actual vehicle application. Themachine uses a specified engagement speed, normally 3600 rpm, and a calculatedinertia to provide the required amount of energy to the test clutch and fluid. The clutchis lubricated by the fluid being evaluated, and each deceleration (i.e., braking) of the system is termed one cycle. To evaluate friction durability many cycles are runconsecutively. Increasing emphasis on friction durability by original equipmentmanufacturers (OEM's) has caused the total number of cycles required to demonstratesatisfactory friction durability to increase from several hundred in the 1980's to morethan 30,000 in some proposed specifications.
• There are two methods of assessing improved friction durability. One is tomaintain certain friction characteristics over a longer period of time (cycles). The secondis to allow less change in each friction parameter over the same number of cycles. Bothmethods provide indications that the vehicle shift characteristics will be consistent overa longer number of miles.
• Said methods comprise adding to, and operating in, an automatic transmissionan automatic transmission fluid comprising (1) a major amount of a base oil and (2) aminor amount of an additive composition which comprises, as essential components atleast Component (A); Component (B); and Component (C) as described below.
• Although the Components above and in the below list are described occasionallywith reference to a function, that function may be one of other functions served by thesame component and should not be construed as a mandatory limiting function.
MANDATORY COMPONENTSComponent (A) Detergent
• Relatively large amounts of metal-containing detergents, such as calciumsulfurized phenates, magnesium phenates, calcium sulfonates, and magnesium phenates are used in formulations according to the present invention. Suitable metalsinclude, but are not limited to, those found in Group 2A of the periodic table.
• It has heretofore been conventional to use such detergents in far lesser quantities,e.g. no more than about 250 ppm of metal, usually no more than about 100 ppm of metal,and most commonly no more than about 50 ppm of metal.
• However, in the practice of the present invention, the amount of detergent ispreferably elevated to a high degree, e.g. above 0.10 wt% and up to about 1.50 wt % forexample, above 0.15 wt% to 1.50 wt% preferably between about 0.15 wt% and about 1.00wt%, most preferably about 0.15-0.50 wt%.
• While not wishing to be bound by theory, it is surmised that these high levels ofdetergent act to increase anti-shudder durability by limiting the thermal and oxidativedegradation of surface-active components.
• These sulfurized phenates may be salts containing a stoichiometric amount ofcalcium, and also generally having a total base number (TBN) of not more than about 300mg KOH/gram. One commercially available calcium phenate which is suitable for thepractice of the instant invention is OLOA 216C, a calcium hydroxide salt of a sulfurizedalkyl phenate having a nominal TBN of about 150, available from Oronite Division ofChevron Chemical Co. HiTEC® 614, a neutral calcium sulfonate available from EthylCorporation, Richmond, Virginia, is also suitable for use in the present invention.
• In a preferred embodiment, the detergent is prepared as an overbased detergent.That is to say, in preparation, the detergent is reacted with a large amount of aninorganic base, e.g. calcium carbonate or magnesium carbonate, and is thus capable ofabsorbing a large excess of acidic products. One such suitable overbased calciumphenate which is suitable for the practice of the present invention is OLOA 219 C, witha total base number of about 260 also available from Oronite.
• In another preferred embodiment, sulfonate detergents are used in the levelsspecified above. One such suitable sulfonate is HiTEC® 611, an overbased calciumdetergent with a TBN of about 300, also available from Ethyl Corporation.
• Finally, also suitable in the present invention are the so-called "superbased"detergents, with exceptionally high TBN (total base number). One such superbaseddetergent is HiTEC® 607, a 410 TBN calcium sulfonate, also available from EthylCorporation.
• It is preferred to have a mixture of detergents, such as a mixture of overbasedcalcium phenate and overbased calcium sulfonate, in roughly equal proportions.
Component (B) Dispersant
• Component (B) comprises at least one oil-soluble phosphorus or boron-containingashless dispersant. The phosphorus or boron-containing ashless dispersantscan be formed by phosphorylating or boronating an ashless dispersant having basicnitrogen and/or at least one hydroxyl group in the molecule, such as a succinimide dispersant, succinic ester dispersant, succinic ester-amide dispersant, Mannich basedispersant, hydrocarbyl polyamine dispersant, or polymeric polyamine dispersant.
• The polyamine succinimides in which the succinic group contains a hydrocarbylsubstituent containing at least 30 carbon atoms are described for example in U.S. Pat.Nos. 3,172,892; 3,202,678; 3,216,936; 3,219,666; 3,254,025; 3,272,746; and 4,234,435. Thealkenyl succinimides may be formed by conventional methods such as by heating analkenyl succinic anhydride, acid, acid-ester, acid halide, or lower alkyl ester with apolyamine containing at least one primary amino group. The alkenyl succinicanhydride may be made readily by heating a mixture of olefin and maleic anhydride to,for example, about 180-220 degrees C. The olefin is preferably a polymer or copolymerof a lower monoolefin such as ethylene, propylene, 1-butene, isobutene and the like andmixtures thereof. The more preferred source of alkenyl group is from polyisobutenehaving a gel permeation chromotography (GPC) number average molecular weight ofup to 10,000 or higher, preferably in the range of about 500 to about 2,500, and mostpreferably in the range of about 800 to about 1,500.
• As used herein the term "succinimide" is meant to encompass the completedreaction product from reaction between one or more polyamine reactants and ahydrocarbon-substituted succinic acid or anhydride (or like succinic acylating agent),and is intended to encompass compounds wherein the product may have amide,amidine, and/or salt linkages in addition to the imide linkage of the type that resultsfrom the reaction of a primary amino group and an anhydride moiety.
• Alkenyl succinic acid esters and diesters of polyhydric alcohols containing 2-20carbon atoms and 2-6 hydroxyl groups can be used in forming the phosphorus-containingashless dispersants. Representative examples are described in U.S. Pat. Nos.3,331,776; 3,381,022; and 3,522,179. The alkenyl succinic portion of these esterscorresponds to the alkenyl succinic portion of the succinimides described above.
• Suitable alkenyl succinic ester-amides for forming the phosphorylated ashlessdispersant are described for example in U.S. Pat. Nos. 3,184,474; 3,576,743; 3,632,511;3,804,763; 3,836,471; 3,862,981; 3,936,480; 3,948,800; 3,950,341; 3,957,854; 3,957,855;3,991,098; 4,071,548; and 4,173,540.
• Hydrocarbyl polyamine dispersants that can be phosphorylated are generallyproduced by reacting an aliphatic or alicyclic halide (or mixture thereof) containing anaverage of at least about 40 carbon atoms with one or more amines, preferablypolyalkylene polyamines. Examples of such hydrocarbyl polyamine dispersants aredescribed in U.S. Pat. Nos. 3,275,554; 3,394,576; 3,438,757; 3,454,555; 3,565,804; 3,671,511;and 3,821,302.
• In general, the hydrocarbyl-substituted polyamines are high molecular weighthydrocarbyl-N-substituted polyamines containing basic nitrogen in the molecule. Thehydrocarbyl group typically has a number average molecular weight in the range ofabout 750-10,000 as determined by GPC, more usually in the range of about 1,000-5,000,and is derived from a suitable polyolefin. Preferred hydrocarbyl-substituted amines or polyamines are prepared from polyisobutenyl chlorides and polyamines having from 2to about 12 amine nitrogen atoms and from 2 to about 40 carbon atoms.
• Mannich polyamine dispersants which can be utilized in forming thephosphorylated ashless dispersant is a reaction product of an alkyl phenol, typicallyhaving a long chain alkyl substituent on the ring, with one or more aliphatic aldehydescontaining from 1 to about 7 carbon atoms (especially formaldehyde and derivativesthereof), and polyamines (especially polyalkylene polyamines). Examples of Mannichcondensation products, and methods for their production are described in U.S. Pat.Nos. 2,459,112; 2,962,442; 2,984,550; 3,036,003; 3,166,516; 3,236,770; 3,368,972; 3,413,347;3,442,808; 3,448,047; 3,454,497; 3,459,661; 3,493,520; 3,539,633; 3,558,743; 3,586,629;3,591,598; 3,600,372; 3,634,515; 3,649,229; 3,697,574; 3,703,536; 3,704,308; 3,725,277;3,725,480; 3,726,882; 3,736,357; 3,751,365; 3,756,953; 3,793,202; 3,798,165; 3,798,247;3,803,039; 3,872,019; 3,904,595; 3,957,746; 3,980,569; 3,985,802; 4,006,089; 4,011,380;4,025,451; 4,058,468; 4,083,699; 4,090,854; 4,354,950; and 4,485,023.
• The preferred hydrocarbon sources for preparation of the Mannich polyaminedispersants are those derived from substantially saturated petroleum fractions andolefin polymers, preferably polymers of mono-olefins having from 2 to about 6 carbonatoms. The hydrocarbon source generally contains at least about 40 and preferably atleast about 50 carbon atoms to provide substantial oil solubility to the dispersant. Theolefin polymers having a GPC number average molecular weight between about 600and 5,000 are preferred for reasons of easy reactivity and low cost. However, polymers of higher molecular weight can also be used. Especially suitable hydrocarbon sourcesare isobutylene polymers.
• The preferred Mannich base dispersants for this use are Mannich base ashlessdispersants formed by condensing about one molar proportion of long chainhydrocarbon-substituted phenol with from about 1 to 2.5 moles of formaldehyde andfrom about 0.5 to 2 moles of polyalkylene polyamine.
• Polymeric polyamine dispersants suitable for preparing phosphorylated ashlessdispersants are polymers containing basic amine groups and oil solubilizing groups (forexample, pendant alkyl groups having at least about 8 carbon atoms). Such materialsare illustrated by interpolymers formed from various monomers such as decylmethacrylate, vinyl decyl ether or relatively high molecular weight olefins, withaminoalkyl acrylates and aminoalkyl acrylamides. Examples of polymeric polyaminedispersants are set forth in U.S. Pat. Nos. 3,329,658; 3,449,250; 3,493,520; 3,519,565;3,666,730; 3,687,849; and 3,702,300.
• The various types of ashless dispersants described above can be phosphorylatedby procedures described in U.S. Pat. Nos. 3,184,411; 3,342,735; 3,403,102; 3,502,607;3,511,780; 3,513,093; 3,513,093; 4,615,826; 4,648,980; 4,857,214 and 5,198,133.
• In another preferred embodiment, the dispersants or the phosphorus-containingdispersants of the present invention are also boronated.
• Methods that can be used for boronating (borating) the various types of ashlessdispersants described above are described in U.S. Pat. Nos. 3,087,936; 3,254,025; 3,281,428; 3,282,955; 2,284,409; 2,284,410; 3,338,832; 3,344,069; 3,533,945; 3,658,836;3,703,536; 3,718,663; 4,455,243; and 4,652,387.
• Preferred procedures for phosphorylating and boronating ashless dispersantssuch as those referred to above are set forth in U.S. Pat. Nos. 4,857,214 and 5,198,133.
• The amount of phosphorylated ashless dispersant on an "active ingredient basis"(i.e., excluding the weight of impurities, diluents and solvents typically associatedtherewith) is generally within the range of about 0.5 to about 7.5 weight percent (wt%),typically within the range of about 0.5 to 6.5 wt%, preferably within the range of about0.5 to about 5.5 wt%, and most preferably within the range of about 1.0 to about 4.5wt%.
• In a preferred embodiment of the present invention, an ashless dispersant withan N/P ratio as set forth in US Patent 5,972,851, which is incorporated herein byreference. In this preferred embodiment, an optional component of the presentinvention is a dispersant having a nitrogen to phosphorus mass ratio between about 3:1and about 10:1. The dispersant of the preferred embodiment can be prepared in at leasttwo ways. In one method, an ashless dispersant is phosphorylated to such a degree thatthe nitrogen to phosphorus mass ratio between about 3:1 and about 10:1. In anotherembodiment, a phosphorylated dispersant and a non-phosphorylated dispersant areblended together such that the total nitrogen to phosphorus mass ratio of the dispersantis between about 3:1 and about 10:1.
• Overall, the dispersant is preferably present in the final fluid in an amount of about1.00% to about 10.00% by weight, more preferably from about 1.00 weight % to about7.00 weight %, most preferably about 3-6 weight %.
Component (C) Friction Modifier
• The compositions of the present invention contain at least one amine-based frictionmodifier, and most preferably a mixture of amine-based friction modifiers. These may bein combination with other friction modifiers as well.
• The amine-based friction modifiers typically include such compounds as fattyamines or ethoxylated fatty amines, ethoxylated aliphatic ether amines, and fatty tertiaryamines. Other suitable nitrogen containing friction modifiers include fatty imidazolines,aliphatic fatty acid amides, and the like. Various other known compounds which aresuitable as friction modifiers include aliphatic carboxylic acids, glycerol esters, aliphaticcarboxylic ester-amides, aliphatic phosphonates, aliphatic phosphates, aliphaticthiophosphonates, and aliphatic thiophosphates. The aliphatic group may contain aboveabout eight carbon atoms so as to render the compound suitably oil soluble.
• Suitable friction modifiers also include metal salts of fatty acids. Preferred cationsare zinc, magnesium, calcium, barium, and sodium and any alkaline, or alkaline earthmetals may, be used. The salts may be overbased by including and excess of cations perequivalent of amine. The excess cations are then treated with carbon dioxide to form thecarbonate. The metal salts are prepared by reacting a suitable salt with the acid to form the salt, and where appropriate adding carbon dioxide to the reaction mixture toform the carbonate of any cation beyond that needed to form the salt. A preferredfriction modifier is zinc oleate.
• Also suitable are aliphatic substituted succinimides formed by reacting one ormore aliphatic succinic acids or anhydrides with ammonia or other primary amines.
• One preferred group of friction modifiers is comprised of the N-aliphatichydrocarbyl-substituted diethanol amines in which the N-aliphatic hydrocarbyl-substituentis at least one straight chain aliphatic hydrocarbyl group free of acetylenicunsaturation and having in the range of about 14 to about 20 carbon atoms.
• Some commercially available friction modifiers which are suitable in the practiceof the invention are the Armeen® series of primary amines (12D,16D, 18D, O, OD, OL,OLD, C, CD, S, SD, T, TD, HT, and HTD); secondary amines (2C, 2T, 2HT, 2-18);tertiary monoalkyl amines (DM12D, DM16D, DM18D, DMOD, DMCD, DMSD, DMTD,DMHTD); tertiary dialkyl amines (M2C, M2HT); tertiary trialkyl amines (3-12, 3-16);diamines, under the tradename Duomeen® (C, CD, T, TTM, OL, LT-4, S); triamines,under the tradename Triameen® T; tetramines, under the tradename Tetrameen® T;ethoxylated amines, under the tradename Ethomeen® (C-12, C-15, C-20, C-25, O-12, O-15,T-12, T-15, T-25, S-12, S-15, S-20, S-25,18-12,18-20,18-25,18-60); and ethoxylateddiamines, under the tradename Ethoduomeen® (T-13, T-20, T-25). Especially preferredare Ethomeen® T-12, an ethoxylated tallow diamine, and Ethomeen® C-12, an ethoxylated cocoalkylamine. All from the above list are available from Akzo NobelChemical Company.
• Also suitable for use as friction modifiers in the scope of the present inventionare alkanolamides derived from C₁₂-C₁₈ fatty acids, e.g. cocoamide and tallowamide.Commercial examples of these alkanolamides include Schercomid SL-ML (lauramidediethanolamine), and Schercomid SOA-E, a C₁₈-amide, each available from ScherChemicals, Inc, New Jersey. Schercomid SL-ML is especially preferred.
• A particularly preferred friction modifier system is composed of a combinationof at least one N-aliphatic hydrocarbyl-substituted diethanolamine and at least one N-aliphatichydrocarbyl-substituted trimethylene diamine in which the N-aliphatichydrocarbyl-substituent is at least one straight chain aliphatic hydrocarbyl group free ofacetylenic unsaturation and having in the range of about 14 to about 20 carbon atoms.Further details concerning this friction modifier system are set forth in U.S. Pat. Nos.5,372,735 and 5,441,656, incorporated herein by reference.
• Another particularly preferred friction modifier system is based on thecombination of (i) at least one di(hydroxyalkyl) aliphatic tertiary amine in which thehydroxyalkyl groups, being the same or different, each contain from 2 to about 4 carbonatoms, and in which the aliphatic group is an acyclic hydrocarbyl group containingfrom about 10 to about 25 carbon atoms, and (ii) at least one hydroxyalkyl aliphaticimidazoline in which the hydroxyalkyl group contains from 2 to about 4 carbon atoms,and in which the aliphatic group is an acyclic hydrocarbyl group containing from about 10 to about 25 carbon atoms. Further details concerning this friction modifier system areset forth in U.S. Pat. No. 5,344,579, incorporated herein by reference.
• Component (i), the di(hydroxyalkyl) aliphatic tertiary amine, has a nitrogen atomto which are bonded two hydroxyalkyl groups and one non-cyclic aliphatic hydrocarbylgroup having 10 to 25 carbon atoms, and preferably 13 to 19 carbon atoms. Thehydroxyalkyl groups of these tertiary amines can be the same or different, but eachcontains from 2 to 4 carbon atoms. The hydroxyl groups can be in any position in thehydroxyalkyl groups, but preferably are in the β-position. Preferably the twohydroxyalkyl groups in component (i) are the same, and most preferably are 2-hydroxyethylgroups. The aliphatic group of these tertiary amines can be straight orbranched chain and it can be saturated or olefinically unsaturated and if unsaturated, ittypically contains from one to three olefinic double bonds. Component (i) can have asingle type of aliphatic group or it can comprise a mixture of compounds havingdifferent aliphatic groups in which the average number of carbon atoms falls within theforegoing range of from 10 to 25 carbon atoms.
• Another set of friction modifiers which is suitable for practice within the scope ofthe present invention includes: 1) at least one dihydroxy alkyl aliphatic tertiary amine(e.g., alkyl C₁₂-C₁₈ and cyclic hydrocarbyl); and 2) at least one aliphatic fatty alkanolamide in which the aliphatic group is an acyclic hydrocarbyl group containing from 12to 18 carbon atoms. The aliphatic fatty alkanol is preferably a dihydroxy alkyl. Especially preferred is an aliphatic primary amine, an aliphatic secondary amine, or amixture thereof, in which the aliphatic group contains from 12 to 18 carbon atoms.
• From the foregoing it will be clear that component (i) can be a single compoundor a mixture of compounds meeting the structural criteria described above.
• The hydroxyalkyl aliphatic imidazolines, component (ii), suitable for use in thepractice of this invention are characterized by having in the 1-position on theimidazoline ring a hydroxyalkyl group that contains from 2 to 4 carbon atoms, and byhaving in the adjacent 2-position on the ring a non-cyclic hydrocarbyl group containing10 to 25 carbon atoms. While the hydroxyl group of the hydroxyalkyl group can be inany position thereof, it preferably is on the β-carbon atom, such as 2-hydroxyethyl, 2-hydroxypropylor 2-hydroxybutyl. Typically the aliphatic group is a saturated orolefinically unsaturated hydrocarbyl group, and when olefinically unsaturated, thealiphatic group may contain one, two or three such double bonds. Component (ii) maybe a single substantially pure compound or it may be a mixture of compounds in whichthe aliphatic group has an average of from 10 to 25 carbon atoms. Preferably thealiphatic group has 15 to 19 carbon atoms, or an average of 15 to 19 carbon atoms. Mostpreferably the aliphatic group has, or averages, 17 carbon atoms. The aliphatic group(s)may be straight or branched chain groups, with substantially straight chain groupsbeing preferred. A particularly preferred compound is 1-hydroxyethyl-2-heptadecenylimidazoline. A commercially available imidazoline based friction modifier essentiallysuitable for use as ii) in the invention is Unamine O, available from Lonza Chemicals.
• It will thus be clear that component (ii) can be a single compound or a mixture ofcompounds meeting the structural criteria described above.
• Generally speaking, the fully formulated final compositions of this invention willoptionally contain up to about 1.25 wt% on an active ingredient basis, and preferablyfrom about 0.005 to about 1.10 wt% on an active ingredient basis of one or more frictionmodifiers, most preferably about 0.005 to about 1.00 wt %.
• In addition to the above mandatory components, the following optionalcomponents may also be present in compositions according to the present invention.
Component (D) Antioxidants
• The compositions of the present invention may include one or more antioxidants,for example, one or more phenolic antioxidants, hindered phenolicantioxidants, additional sulfurized olefins, aromatic amine antioxidants, secondaryaromatic amine antioxidants, sulfurized phenolic antioxidants, oil-soluble coppercompounds, phosphorus-containing antioxidants (e.g. organic phosphites), andmixtures thereof.
• Suitable exemplary compounds include 2,6-di-tert-butylphenol, liquid mixturesof tertiary butylated phenols, 2,6-di-tert-butyl-4-methylphenol, 4,4'-methylenebis(2,6-di-tert-butylphenol),2,2'-methylenebis(4-methyl-6-tert-butylphenol), mixed methylene-bridgedpolyalkyl phenols, 4,4'-thiobis(2-methyl-6-tert-butylphenol), N,N'-di-sec-butyl-p-phenylenediamine,4-isopropylaminodiphenyl amine, phenyl- α-naphthyl amine, andphenyl-β-naphthyl amine.
• Especially preferred antioxidants include diphenyl amine derived antioxidants;such as Naugalube® 438-L.
• In the class of amine antioxidants, oil-soluble aromatic secondary amines;aromatic secondary monoamines; and others are suitable. Suitable aromatic secondarymonoamines include diphenylamine, alkyl diphenylamines containing 1 to 2 alkylsubstituents each having up to about 16 carbon atoms, phenyl-α-naphthylamine,phenyl- γ-naphthylamine, alkyl- or aralkylsubstituted phenyl- α-naphthylaminecontaining one or two alkyl or aralkyl groups each having up to about 16 carbon atoms,alkyl- or aralkyl-substituted phenyl- β-naphthylamine containing one or two alkyl oraralkyl groups each having up to about 16 carbon atoms, alkylated p-phenylenediamines available from Goodyear under the tradename "Wingstay 100" and fromUniroyal, and similar compounds.
• The preferred type of aromatic amine antioxidant is that embodied in thecommercial product Naugalube 483L is an alkylated diphenylamine of the generalformula :R¹--C₆H₄--NH--C₆H₄--R²wherein R¹ is an alkyl group (preferably a branched alkyl group) having 8 to 12 carbonatoms, (more preferably 8 or 9 carbon atoms) and R² is a hydrogen atom or an alkylgroup (preferably a branched alkyl group) having 8 to 12 carbon atoms, (morepreferably 8 or 9 carbon atoms). Most preferably, R¹ and R² are the same. Particularly preferred is a nonylated diphenyl amine containing 4,4'-dinonylated diphenyl amine; abis(4-nonylphenyl)(amine) wherein the nonyl groups are branched.
• In the class of phenolic antioxidants, suitable compounds include ortho-alkylatedphenolic compounds, e.g. 2-tert-butylphenol, 2,6-di-tertbutylphenol, 4-methyl-2,6-di-tertbutylphenol,2,4,6-tri-tertbutylphenol, and various analogs andhomologs or mixtures thereof; one or more partially sulfurized phenolic compounds asdescribed in US Patent 6,096,695, the disclosure of which is incorporated herein byreference; methylene-bridged alkylphenols as described in U.S. Pat. No. 3,211,652, thedisclosure of which is incorporated herein by reference.
• Antioxidants may be optionally included in the fully formulated final inventivelubricating composition at from about 0.00 to about 5.00 weight percent, morepreferably from about 0.01 weight % to about 1.00 weight %, most preferably about 0.05wt % to about 0.50 wt %.
Component (E) Extreme Pressure/Anti-Wear
• The automatic transmission fluids of the present invention may further includeanti-wear/extreme pressure additives.
• When the desired phosphorus content of the finished fluid is not completelysupplied by use of a phosphorus-containing ashless dispersant (or a boron- andphosphorus-containing ashless dispersant), the remainder of the phosphorus content ispreferably supplied by inclusion in the composition of one or more phosphorus-containingesters or acid-esters such as oil-soluble organic phosphites, oil-soluble organic acid phosphites, oil-soluble organic phosphates, oil-soluble organic acidphosphates, oil-soluble phosphoramidates. Examples include trihydrocarbylphosphates, trihydrocarbyl phosphites, dihydrocarbyl phosphates, dihydrocarbylphosphonates or dihydrocarbyl phosphites or mixtures thereof, monohydrocarbylphosphates, monohydrocarbyl phosphites, and mixtures of any two or more of theforegoing. Oil-soluble amine salts of organic acid phosphates are a preferred categoryof auxiliary phosphorus-containing additives for use in the fluids of this invention.Sulfur-containing analogs of any of the foregoing compounds can also be used, but areless preferred. Suitable commercially available auxiliary phosphorus additives includeamine phosphate antiwear/extreme pressure agents, available from Ciba-GeigyCorporation as Irgalube® 349 and R.T. Vanderbilt Inc. as Vanlube® 672.
• Also suitable are sulfurized fatty acid esters, e.g. the Sul-Perm® brand ofsulfurized fatty acid esters from Keil Chemical, and sulfurized dithiocarbamates, andalkyl thiadiazoles such as HiTEC® 4312 and 4313, available from Ethyl Corporation,Richmond, Virginia.
• The extreme pressure/anti wear additive is preferably present in the final fully-formulatedfluid in an amount of from 0.00 to about 1.00 weight %, more preferablyfrom about 0.01 to about 0.50 weight %.
Component (F) - Viscosity Index Improver
• The compositions of the present invention optionally, but preferably, contain aviscosity index improver (VII). Preferred VIIs include, but are not limited to, olefin copolymer VIIs, polyalkylmethacrylate VIIs and styrene-maleic ester VIIs. Of these,polyalkylmethacrylate VIIs are particularly preferred. The viscosity index improver issupplied in the form of a solution in an inert solvent, typically a mineral oil solvent,which usually is a severely refined mineral oil. The viscosity index improver solution asreceived often will have a boiling point above 200°C, and a specific gravity of less than 1at 25 °C. Preferably, the viscosity index improver will have sufficient shear stabilitysuch that the finished composition possesses a kinematic viscosity of at least 5, andmore preferably at least 6.8, cSt at 100 °C after 40 cycles in the FISST (Fuel Injector ShearStability Test) of ASTM D-5275.
• The VII in the present invention will also preferably have less than 5% shear losson the tapered roller bearing test.
• On an active ingredient basis (i.e., excluding the weight of inert diluent orsolvent associated with the viscosity index improver as supplied), the finished fluidcompositions of this invention will normally contain in the range of about 0 to about 15wt% of the polymeric viscosity index improver. Small departures from this range maybe resorted to as necessary or desirable in any given situation.
• Suitable materials for use as component (F) include styrene-maleic ester VIIssuch as LUBRIZOL® 3702, LUBRIZOL®3706 and LUBRIZOL®3715 available from TheLubrizol Corporation; polyalkylmethacrylate VIIs such as those available from RÖHMGmbH (Darmstadt, Germany) under the trade designations: VISCOPLEX® 5543,VISCOPLEX® 5548, VISCOPLEX® 5549, VISCOPLEX® 5550, VISCOPLEX® 5551 and VISCOPLEX® 5151, from Rohm & Haas Company (Philadelphia, Pennsylvania) underthe trade designations ACRYLOID® 1277, ACRYLOID® 1265 and ACRYLOID® 1269, andfrom Ethyl Corporation (Richmond, Virginia) under the trade designation HiTEC® 5710viscosity index improver; and olefin copolymer VIIs such as HiTEC® 5747 VII, HiTEC®5751 VII, HiTEC® 5770 VII and HiTEC® 5772 VII available from Ethyl Corporation andSHELLVIS® 200 available from Shell Chemical Company. Mixtures of the foregoingproducts can also be used as well as dispersant and dispersant/antioxidant VIIs.
• Preferably, the viscosity index improver will be provided as a hydrocarbonsolution having a polymer content in the range of from about 25 to about 80 wt% and anitrogen content in the range of about 0 to about 0.5 wt%. Such products preferablyexhibit a permanent shear stability index (a PSSI value) using ASTM test method D-3945Aof no higher than about 75, preferably 50 or less, and most preferably 35 or less.
• Preferred is a dispersant polymethacrylate viscosity index improver such asHiTEC® 5738, or a non dispersant polymethacrylate viscosity index improver such asHiTEC®5739, both products of Ethyl Corporation, Richmond Virginia, or a mixture ofdispersant and non-dispersant viscosity index improvers. Especially preferred is anultra high shear stable dispersant polymethacrylate viscosity index improver such asHITEC 5769, also a product of Ethyl Corporation, Richmond, Virginia.
• Quantitatively, the viscosity index improver may be present in an amount offrom 0-25% by weight, preferably from 5-20% by weight.
Component (G) - Anti-Rust
• Various known anti-rust agents or additives are known for use in transmissionfluids, and are suitable for use in the fluids according to the present invention.Especially preferred are alkyl polyoxyalkylene ethers, such as Mazawet® 77, C-8 acidssuch as Neofat® 8, oxyalkyl amines such as Tomah PA-14, 3-decyloxypropylamine, andpolyoxypropylene-polyoxyethylene block copolymers such as Pluronic® L-81.
• Mixtures of the above anti-rust agents are especially preferred. Anti-rust agentsare preferably used in low quantities, e.g. less than about 0.2 wt %, preferably fromabout 0.01 to about 0.15 weight %.
Component (H) - Anti-Foam/Surfactant
• Anti-foam/Surfactant agents may also be included in a fluid according to thepresent invention. Various agents are known for such use. Especially preferred arecopolymers of ethyl acrylate and hexyl ethyl acrylate, such as PC-1244, available fromSolutia. Also preferred are silicone fluids such as 4% DCF. Mixtures of anti-foam agentsare especially preferred.
• Given their high activity levels, anti foam agents are generally present in smallamounts, from about 0.00 - 0.10 weight %, more preferably between about 0.02-0.07 wt%, most preferably about 0.05 wt %.
Component (I) - Dye
• It is preferred to add a colorant to the fluid to give it a unique character which isdetectable. Generally, azo class dyes are used, such as C.I.Solvent Red 24 or C.I. Solvent Red 164, as set forth in the "Colour Index" of the American Association ofTextile Chemists and Colorists and the Society of Dyers and Colourists (U.K.) which isincorporated herein by reference. For automatic transmission fluids, Automate RedDye is especially preferred. Dye is present in a very minimal amount, usually less than400 ppm, preferably between about 200-300 ppm in the finished oil.
Component (J) - Oil
• If the additives are provided in an additive package concentrate, a suitablecarrier diluent is added to ease blending, solubilizing, and transporting the additivepackage. The diluent oil needs to be compatible with the base oil and the additivepackage. Generally, the diluent is present in the concentrate in an amount of between 5-20%,although it can vary widely with application. Generally speaking, less diluent ispreferable as it lowers transportation costs and treat rates. A suitable diluent is aprocess oil of lubricating viscosity.
• If the inventive composition is to be prepared as a concentrate, then base oil maybe omitted and an appropriate adjustment made in the weight % of each of the aboveoptional and mandatory ingredients to prepare a suitable concentrate, taking care thatsolubility and compatibility is maintained. However, if a fully formulated fluid is to beprepared, then base oil is a mandatory component.
• The base oils used in forming the automatic transmission fluids of this inventioncan be any suitable natural or synthetic oil having the necessary viscosity properties forthis usage. Natural oils include animal oils and vegetable oils (e.g., castor oil, lard oil etc.), liquid petroleum oils and hydrorefined, severely hydrotreated, iso-dewaxed,solvent-treated or acid-treated mineral lubricating oils of the paraffinic, naphthenic andmixed paraffinic-naphthenic types. Oils of lubricating viscosity derived from coal orshale are also useful base oils.
• The synthetic lubricating oils suitable for use in this invention include one of anynumber of commonly used synthetic hydrocarbon oils, which include, but are notlimited to, poly-alpha-olefins, synthetic esters, alkylated aromatics, alkylene oxidepolymers, interpolymers, copolymers and derivatives thereof where the terminalhydroxyl groups have been modified by esterification, etherification etc., esters ofdicarboxylic acids and silicon-based oils. Thus, the base oil may be composed entirelyof a natural oil such as mineral oil of suitable viscosity or it may be composed entirelyof a synthetic oil such as a poly-alpha-olefin oligomer of suitable viscosity.
• Likewise, the base oil may be a blend of natural and/or synthetic base oilsprovided that the blend has the requisite properties for use in the formation of anautomatic transmission fluid. Ordinarily, the base oil should have a kinematic viscosityin the range of 3 to 8 centistokes (cSt) at 100 °C. Preferred automatic transmission fluidsused in the practice of this invention can be formulated without a viscosity indeximprover so as to possess a kinematic viscosity of at least 3.0 cSt at 100°C and aBrookfield viscosity of no more than 20,000 cP at -40 °C, or formulatedusing a viscosity index improver so as to possess a kinematic viscosity of at least 6.8 cStat 100 °C and a Brookfield viscosity of no more than 20,000 cP at -40 °C.
• Suitable base stock oil includes, preferably, Group I, II, and III base oils, as areknown to those of skill in the art. In certain instances, usually depending on the finaluse of the lubricant composition according to the present invention, Group I ispreferred, and in other instances, Group II and III are preferred.
• Group I base stocks contain less than 90% saturates (as determined by ASTM D2007) and/or greater than 0.03 percent sulfur (as determined by ASTM D 2622, D 4294,D 4927, or D 3120) and have a viscosity index greater than or equal to 80 and less than120 (as determined by ASTM D 2270).
• Group II base stocks contain greater than or equal to 90 % saturates and less thanor equal to 0.03 % sulfur and have a viscosity index greater than 80 and less than 120using the above noted test methods. Group II + oils may also be used. These are oilswhich have a VI at the high end of the VI spectrum, e.g. about 120.
• Group III base stocks contain greater than or equal to 90 percent saturates andless than or equal to 0.03 % sulfur and have a viscosity index greater than or equal to120 using the tests noted above.
• In another embodiment, the transmission fluid contains less than 5% poly-alpha-olefins(PAO) and is more preferably PAO free.
Component (K) - Additional ComponentsSeal Swell Agents
• The automatic transmission fluids of the present invention may further includeseal swell agents. Seal swell agents such as esters, adipates, sebacates, azealates, phthalates, sulfones, alcohols, alkylbenzenes, substituted sulfolanes, aromatics, ormineral oils cause swelling of elastomeric materials used as seals in engines andautomatic transmissions.
• Alcohol-type seal swell agents are generally low volatility linear alkyl alcohols,such as decyl alcohol, tridecyl alcohol and tetradecyl alcohol.
• Alkylbenzenes useful as seal swell agents include dodecylbenzenes,tetradecylbenzenes, dinonyl-benzenes, di(2-ethylhexyl)benzene, and the like.
• Substituted sulfolanes (e.g. those described in U.S. Pat. No. 4,029,588,incorporated herein by reference) are likewise useful as seal swell agents incompositions according to the present invention.
• Mineral oils useful as seal swell agents in the present invention include lowviscosity mineral oils with high naphthenic or aromatic content.
• Aromatic seal swell agents include the commercially available Exxon Aromatic200 ND seal swell agent.
• Commercially available examples of mineral oil seal swell agents includeExxon® Necton®-37 (FN 1380) and Exxon® Mineral Seal Oil (FN 3200).
• When used in the ATF of the present invention, a seal swell agent will typicallycomprise from about 1 to about 30 wt. %, preferably from about 1 to about 20 wt. %,most preferably from about 1 to about 10 wt. %, based on the total weight of ATF.
Corrosion Inhibitors
• The automatic transmission fluids of the present invention may further includeadditional corrosion inhibitors (it should be noted that some of the earlier mentionedcomponents, e.g. monoalkyl and dialkyl thiadiazole each have copper corrosioninhibition properties). Other suitable additional inhibitors of copper corrosion includeether amines, polyethoxylated compounds such as ethoxylated amines and ethoxylatedalcohols, imidazolines, and the like.
• Thiazoles, triazoles and thiadiazoles may also be used in the present invention.Examples include benzotriazole; tolyltriazole; octyltriazole; decyltriazole;dodecyltriazole; 2-mercaptobenzothiazole; 2,5-dimercapto-1,3,4-thiadiazole; 2-mercapto-5-hydrocarbylthio-1,3,4-thiadiazoles;and 2-mercapto-5-hydrocarbyldithio-1,3,4-thiadiazoles.The preferred compounds are the 1,3,4-thiadiazoles, especially the 2-hydrocarbyldithio-5-mercapto-1,3,4-dithiadiazoles,a number of which are available asarticles of commerce. These may be present in an amount of from 0.00 to 0.50 weightpercent, more preferably from about 0.01 to about 0.10 weight percent, based on thefinal formulation.
• In selecting any of the foregoing optional additives, it is important to ensure thatthe selected component(s) is/are soluble or stably dispersible in the additive packageand finished ATF composition, are compatible with the other components of thecomposition, and do not interfere significantly with the performance properties of thecomposition, such as the friction, viscosity and/or shear stability properties, needed orat least desired in the overall finished composition.
• In general, the ancillary additive components are employed in the oils in minoramounts sufficient to improve the performance characteristics and properties of thebase fluid. The amounts will thus vary in accordance with such factors as the viscositycharacteristics of the base fluid employed, the viscosity characteristics desired in thefinished fluid, the service conditions for which the finished fluid is intended, and theperformance characteristics desired in the finished fluid. However, generally speaking,the following concentrations (weight percent unless indicated otherwise) of theadditional components (active ingredients) in the base fluids are illustrative:

  Component	Typical Range	Preferred Range
  D	0.00 - 5.00 wt %	0.01-1.00 wt %
  E	0.00 - 1.00 wt %	0.01 - 0.50 wt %
  F	0 - 25 wt %	2-20 wt %
  G	0.00 - 0.2 wt %	0.01 - 0.15 wt %
  H	0.00 - 0.10 wt %	0.20 - 0.70 wt %
  I	< 400 ppm	200-300 ppm
  J	Balance	Balance

• It will be appreciated that the individual components employed can beseparately blended into the base fluid or can be blended therein in varioussubcombinations, if desired. Ordinarily, the particular sequence of such blending stepsis not critical. Moreover, such components can be blended in the form of separate solutions in a diluent. It is preferable, however, to blend the additive components usedin the form of a concentrate, as this simplifies the blending operations, reduces thelikelihood of blending errors, and takes advantage of the compatibility and solubilitycharacteristics afforded by the overall concentrate.
• Additive concentrates can thus be formulated to contain all of the additivecomponents and if desired, some of the base oil component, in amounts proportioned toyield finished fluid blends consistent with the concentrations described above. In mostcases, the additive concentrate will contain one or more diluents such as light mineraloils, to facilitate handling and blending of the concentrate. Thus concentratescontaining up to about 50% by weight of one or more diluents or solvents can be used,provided the solvents are not present in amounts that interfere with the low and hightemperature and flash point characteristics and the performance of the finished powertransmission fluid composition. In this connection, the additive components utilizedpursuant to this invention should be selected and proportioned such that an additiveconcentrate or package formulated from such components will have a flash point of 170°C or above, and preferably a flash point of at least 180 °C, using the ASTM D-92 testprocedure.
• In the present invention, the finished fluid or concentrate should be essentiallyfree of phenolic antioxidants and sulfurized fats.
EXAMPLES
• Illustrative compositions suitable for use in the practice of this invention arepresented in the following Examples, wherein all parts and percentages are by weightunless specified otherwise.
• The fluids prepared in the Examples were then subjected to testing undercommonly known tests, including the lowspeed SAE #2 rig, under the conditionsnoted, and the GM plate clutch friction test (GM performance specification GM 6417 M,April 1997) run according to Dexron® III procedures. Briefly, this test involvesengaging the clutch at the rate of four cycles per minute for 100 hours (i.e., 24,000cycles) at 135 degrees C. The DEXRON® III Band Clutch Test limit for the mid-pointtorque is 185-220 Nm.
• The GM Dexron III Cycling Test (GM-6297-M), revised April 1993; correspondingto the Ford Mercon V Friction Durability Test (Dexron 5 Specification 3.9, RevisedJul 1,1996 and October 1, 1998 which sets limits on shift times for 20,000 shift cycles. Shiftingfrom 1st to 2nd gear, 0.30-0.75 seconds; from 2nd to 3rd gear 0.30 to 0.75 sec.
• The FZG wear test, conducted in the FZG gear rig test machine. This test, IP(Institute of Petroleum) 334/79, which is incorporated herein by reference, measureslubricity, and in the test, two steel spin gears are rotated together for a series of 75minute stages. The relative torque between the gears is increased by a fixed amountafter each stage and the gears are run together for a given period after which they areexamined for wear or damage. The result of the test is quoted in terms of the final pass stage and the first fail stage. The test is technically equal to ASTM D 5182-97. This testcan be conducted at selected temperatures, nominally 90 degrees C and 150 degrees C.
• Finally, the compositions were subjected to the Aluminum Beaker Oxidation Test(ABOT) as described in SAE Technical paper series 881673. Compositions according tothe present invention resisted oxidation for at least 500 hours.
• All publications, patents, or other generally known information cited above isincorporated herein by reference as if fully set forth herein.

  Composition of Examples
  Component	Composition	Ex. 3 (invention)	Ex. 2 (not of invention)	Ex. 3. (commercially avail. Product)
  A	Overbase Calcium Sulfonate Detergent	0.5	0.00	Believed to have 500-600 ppm deterg.
  	Overbase Calcium Phenate Detergent	0.5	0.05
  B	Boronated phosphorylated succinimide dispersant	3.77	3.77	Believed to have a conventional additive pack, which would include VII, a friction modifier, antioxidants, anti foam agents and other conventional optional components.
  C	Ethoxylated Amine; n-alkyl tallow amine	0.08	0.15
  C	n-oleyl diamino propane	0.003	0.005
  D	Diphenyl amine	0.26	0.20
  D	Phenolic antioxidant (2,6-di tert-butyl phenol)	0.20	0.00
  E, F, G, H, I , J	EP agents, VII, anti-rust; anti foam; dyes, and base oils	94.677	95.135
  	TOTAL	100.00	100.00	100.00

• Turning now to Figures 1-6, it may clearly be seen that, when compared tocomparative examples 1 and 2, a composition according to the present invention hasexcellent initial anti-shudder properties, excellent friction durability, extended anti-shudderperformance, and oxidation resistance.
• With specific reference to Figure 1, it may be seen that the coefficient of frictionfor fluids of example 3 (according to the invention) remains within the acceptableparameters of the ECCC Friction durability test on theSAE #2 rig of 200 hours underthe stated conditions. The coefficient of friction, even after 216 hours, remains between0.140 and 0.150.
• Turning now to figure 2, it may be seen that the friction durability of fluidsaccording to example 3, when calculated on hours to negative slope (which indicatespresence of shudder) lasts at least 200 hours.
• Turning now to figure 3, the GM plate clutch friction test (anti-shudder) underthe stated conditions, it is clear that after 3600 cycles, the fluid according to the presentinvention has a level tail without the characteristic rooster tail which indicates shudderor stick-slip as seen in Examples 1 and 2.
• The presence of a significant "rooster tail" in this test would indicate a problemwith poor or rough shift feel characteristics in the vehicle which used the fluid.
• Turning now to figure 4, it may be seen that the initial anti-shuddercharacteristics of the instant inventive fluid compositions are at least as good as any of the comparative examples in the GM plate clutch friction test under the statedconditions.
• Figure 5 illustrated the degradation in performance of a fluid of comparativeexample 2 (not of the invention) under the ECCC friction durability test run on theSAE#2 low speed rig. After about 72 hours, a considerable degradation is seen. Thereafter,the vehicle can be expected to shudder.
• Figure 6 illustrates the ECCC friction durability results on theSAE #2 low speedrig for Example 2. The coefficient of friction has dropped, after 120 hours, to between0.130 and 0.120, which would result in the loss of torque and fuel economy in a vehicle.
• This invention is susceptible to considerable variation in its practice.Accordingly, this invention is not limited to the specific exemplifications set forthhereinabove. Rather, this invention is within the spirit and scope of the appendedclaims, including the equivalents thereof available as a matter of law.
• The patentee does not intend to dedicate any disclosed embodiments to thepublic, and to the extent any disclosed modifications or alterations may not literally fallwithin the scope of the claims, they are considered to be part of the invention under thedoctrine of equivalents.

Claims (19)

1. An automatic transmission fluid, comprising:

   (1) a major amount of a base oil, and

   (2) a minor amount of an additive comprising:

   (A) at least 0.10 wt. %, based on the fluid, of a metal-containingdetergent,

   (B) a dispersant, and

   (C) a mixture of at least two different friction modifiers.
2. An automatic transmission fluid, comprising:

   (1) a major amount of a base oil and

   (2) a minor amount of an additive comprising:

   (A) at least 0.25 wt %, based on the fluid, of a metal-containingdetergent,

   (B) a dispersant, and

   (C) a mixture of at least two amine-based friction modifiers.
3. An automatic transmission fluid as claimed in Claim 1 or Claim 2, whereincomponent (A) is a calcium containing detergent.
4. An automatic transmission fluid as claimed in Claim 3, wherein component (A) isa calcium phenate, calcium sulfonate, or mixture thereof.
5. An automatic transmission fluid as claimed in any preceding claim, wherein themetal containing detergent is an overbased calcium sulfonate.
6. An automatic transmission fluid as claimed in any preceding claim, whereincomponent (A) is present in an amount from 0.25 to 1.5 wt. %.
7. An automatic transmission fluid as claimed in Claim 6, wherein component (A) ispresent in an amount from 0.75 wt. % to 1.00 wt. %.
8. An automatic transmission fluid as claimed in any preceding claim, whereincomponent (B) is a succinimide dispersant.
9. An automatic transmission fluid as claimed in Claim 8, wherein the succinimideis boronated, phosphorylated, or boronated and phosphorylated.
10. An automatic transmission fluid as claimed in any preceding claim, wherein themixture of friction modifiers comprises a mixture of an ethoxylated amine and afatty polyamine.
11. An automatic transmission fluid as claimed in any preceding claim, whereincomponent C is selected from the group consisting of ethoxylated fatty amines,aliphatic fatty alkanol amides, aliphatic primary amines, aliphatic secondaryamines, and aliphatic fatty imidazolines.
12. An automatic transmission fluid as claimed in any preceding claim furthercomprising at least one viscosity index improver, antioxidant, anti rust, or anti foam agent.
13. An automatic transmission fluid as claimed in any preceding claim, furthercomprising an additional phosphorus source.
14. An automatic transmission fluid as claimed in Claim 13, wherein the phosphorussource is dibutyl hydrogen phosphite.
15. An automatic transmission fluid as claimed in any preceding claim, furthercomprising a shear stable viscosity index improver.
16. The automatic transmission fluid as claimed in any preceding claim furthercomprising at least one additive selected from the group consisting of extremepressure/antiwear agents, seal swell agents, foam inhibitors, rust inhibitors,viscosity index improvers, lubricity agents, and dyes.
17. The automatic transmission fluid as claimed in any preceding claim, wherein thefluid has a friction durability of at least 200 hours on the ECCC friction durabilitytest as measured on the SAE #2 low speed rig.
18. A method of improving friction durability and anti-shudder performance of anautomatic transmission said method comprising adding to said automatictransmission an automatic transmission fluid according to any preceding claim; and operating said automatic transmission.
19. Use in a transmission fluid comprising:

    (1) a major amount of a base oil; and

    (2) a minor amount of an additive comprising:

    (A) at least 0.10 %, based on the fluid, of a metal-containing detergent,

    (B) a dispersant, and

    (C) a mixture of at least two different friction modifiers

    to improve the friction durability and anti-shudder performance of thetransmission.

Images