DE68907288T2 - Friction-reducing hydroxy ether amines for power transmission fluids and wear protection additives that can be used with them. - Google Patents

Description

The present invention relates to certain hydrocarbon-soluble or dispersible hydroxyetheramine friction modifier additives for power transmission fluids, particularly automatic transmission fluids.

There are many examples, as is well known, particularly in boundary lubrication conditions where two moving surfaces in contact with each other must be lubricated or otherwise protected to prevent wear and ensure continuous motion. There are other examples where friction between two rubbing surfaces should be varied, but not necessarily minimized. By controlling friction between two surfaces, the force required to transfer motion from one surface to the other is also controlled.

For example, one special property that is intended to be imparted to certain lubricating oil compositions adapted for use as automatic transmission fluid is the friction-modifying characteristic of the fluid. This property distinguishes automatic transmission fluids (ATF) from other lubricants and, in fact, it also distinguishes between ATF types. This characteristic has attracted the most attention of both transmission manufacturers and fluid manufacturers for many years. This attention stems from the fact that the friction requirements of an ATF are unique and depend on the design of the transmission and clutch as well as the type of clutch disc material used.

Another property that should be imparted to lubricating oil compositions, including automatic transmission fluids, is reduced wear, such as bearing and power component wear.

As is also well known, both wear and friction change can be controlled by the addition of suitable additives with varying degrees of success.

Although there are many known additives that can be classified as anti-wear or friction modifier additives, it is also known that many of these additives act in different physical or chemical ways and often compete with each other, e.g. they may compete for the surface area of the moving metal parts that are subject to lubrication. Therefore, extreme care must be taken in the selection of these additives to ensure compatibility and effectiveness.

The metal dihydrocarbon dithiophosphates are one of the additives known to exhibit antioxidant and antiwear properties. The most widely used additives of this class are the zinc dialkyldithiophosphates (ZDDP), which are conventionally used in lubricant compositions. Although such zinc compounds offer excellent oxidation resistance and exhibit excellent antiwear properties, they can be corrosive.

Both antiwear and friction modifiers work by forming a coating on the surface of the moving metal parts. The bonds of the coating are generally created by physical or chemical means. Consequently, if the bond between the antiwear agent and the metal part is stronger than the bond between the friction modifier and the metal part, the antiwear agent will replace the friction modifier on the metal surface, i.e. at the metal/fluid boundary lubrication interface. This results in a loss of the ability of the friction modifier to perform its expected effect.

Various tests have been designed by automakers to measure ATF friction and anti-wear properties and to evaluate the performance of additives in relation to the requirements of specific transmission designs and their ability to provide transmission durability and effortless shifting under a variety of road conditions.

Friction change is typically evaluated using an SAE No. 2 friction apparatus. In this test, the friction machine's engine and flywheel (filled with the fluid being tested) are accelerated to constant speed, the engine is stopped, and the flywheel speed is reduced to 0 by engaging the clutch. The clutch plates are then released, the flywheel is accelerated back to constant speed, and the clutch assembly, which is submerged in the test fluid, is re-engaged. This procedure is repeated many times, with each clutch engagement referred to as a cycle.

During application of the clutch, the friction torque is recorded as a function of time. The friction values obtained are either the torque curves themselves or the friction coefficients calculated from the torque curves. The shape of the desired torque curve is set by the car manufacturers. One way to express this shape mathematically is to determine the torque: (a) when the flywheel speed is halfway between the maximum, selected, constant speed and speed 0 (such torque measurement is referred to here as TD) and (b) when the flywheel speed approaches 0 (such torque measurement is referred to here as T₀). Such torques can be used to determine the torque ratio, which is expressed as T₀/TD, or alternatively to determine the torque difference, which is expressed as T₀-TD. The optimal target values for torque ratio and torque differential are specified by the car manufacturers. As the T₀/TD exceeds 1 in an increasing manner, a transmission typically exhibits shorter, harsher shifts when changing gears. On the other hand, as T₀/TD falls below 1, there is a greater risk of clutch slipping when shifting the transmission. Similar relationships exist with respect to a target T₀-TD value of 0.

Although many automatic transmission fluids achieve target values of T�0;/TD after a minimum number of cycles can, it becomes increasingly difficult to maintain such desired values as the number of cycles is increased. The ability of an ATF to maintain such desired frictional properties is referred to herein as frictional stability or durability. A high level of frictional stability is difficult to achieve with ATFs containing certain antiwear additives. It is believed that as the ATF ages under the influence of frictional heat, the antiwear agent may degrade and the decomposition products replace conventional friction modifiers at the metal/fluid boundary lubrication interface. As a result, the fluid may exhibit varying frictional properties.

Attempts to improve friction stability simply by adding more friction modifier have not been successful, as this tends to reduce the static slip torque (TS) of the fluid. This parameter, expressed as the static slip torque ratio (TS/TD), reflects the relative tendency of engaged parts such as clutch kits, bands and drums to slip under load. If this value is too low, slippage can affect the driveability and safety of the vehicle.

Recently, more stringent requirements regarding automatic transmission fluids have been set by one or more automakers. The desire to increase fuel economy has led to a reduction in the size of cars and transmissions, smaller engines and higher shift speeds, and increasing use of torque converter clutches, one-way clutches and a shift toward front-wheel drive.

Thus, the design of transmissions has undergone radical changes, necessitating the formulation of ATF additives capable of meeting these new and more stringent requirements for the properties necessary to adapt to such design changes.

No base oil alone can even come close to the many special properties required for ATF operation Consequently, it is necessary to use several chemical additives, each designed to impart or improve a specific property to the fluid. It therefore becomes particularly advantageous if an additive can perform more than one function, thereby reducing the number of additives that must be present in the formulation.

Therefore, there has been a continuing search for new additives that possess one or more properties that make them suitable for use in ATF compositions as well as in oleaginous or oily compositions. There has also been a search for new combinations of additives that not only provide ATF compositions as well as oleaginous or oily compositions with the various specific properties required, but are compatible with one another in the sense that they neither exhibit a significant tendency to compete with one another nor otherwise reduce the effectiveness of the various additives in the compositions. The present invention was developed in response to this search.

US-A-2 290 880 discloses ethers of alcohol amines which can be used as interface modifying agents in a variety of ways. The compounds are said to be useful in lubricating oils and the like, thus enabling the preparation of effective fine drilling oils, cutting oils, drilling oils, wire drawing oils, extreme pressure lubricants and the like.

US-A-3 255 253 discloses amine-containing polyols which are prepared by first cyanoethylating an alcohol in the presence of a basic catalyst. The cyanoethylated alcohol is then hydrogenated to form a primary amine, after which the primary amine is reacted with an alkylene oxide in the presence of a basic catalyst to form the desired amine-containing polyol. The amine-containing polyols are said to be useful in the manufacture of polyurethane products, as hardeners for polyepoxide resins and in the production of coatings and plasticizers.

US-A-3 456 012 relates to polyolefin adducts of γ-alkoxypropylamines with surfactant properties.

US-A-3 464 925 relates to hydraulic fluids containing certain aminotriols. The aminotriols are obtained by heating propylene oxide and triisopropylamine in the presence of an alkali catalyst under pressure.

US-A-3 705 139 discloses alkyl sulfide compounds having the formula:

R₁-S-R₂-A-(R₃O)nZ

wherein R₁ represents a hydrocarbon group having 6 to 22 carbon atoms, R₂ and R₃ each represent a hydrocarbon group having 1 to 4 carbon atoms, A may represent nitrogen, n may represent an integer in the range of 0 to 100, and Z may represent hydrogen. The alkyl sulfide compounds are disclosed as antistatic agents.

US-A-4 201 684 relates to lubricating oil adapted for use as a crankcase lubricant in internal combustion engines and containing a friction-reducing amount of a sulfurized fatty acid amide, ester or ester-amide of an oxyalkylated amine.

US-A-4 231 883 relates to the use of an alkoxylated hydrocarbon amine in a lubricating oil or fuel to reduce the friction of an internal combustion engine in which the lubricating oil or fuel is used. An example of the alkoxylated hydrocarbon amine compounds disclosed in this patent is N,N-bis(2-hydroxyethyl)oleylamine.

US-A-4 486 324 discloses an aqueous hydraulic fluid comprising at least 80% water and containing a hydrocarbon-substituted succinic acid, a zinc dihydrocarbon dithiophosphate, a hydroxyalkylamine, sodium alkylbenzenesulfonate and optionally a polyalkylene glycol monofatty acid ester.

US-A-4 650 865 relates to a process for the preparation of tertiary ether amines which exhibit surface-active properties. The tertiary ether amines can be used as surfactants and as starting compounds for the preparation of surface-active derivatives, such as amine oxides and quaternary ammonium compounds.

US-A-4 129 508 relates to lubricant and fuel compositions characterized by improved demulsifying properties. The patent discloses an automatic transmission fluid that includes a number of additives including a dialkyl phosphite, the reaction product of a polyisobutylene substituted succinic anhydride, commercial tetraethylene pentamine and boric acid prepared as described in US-A-3 254 025, and a conventional friction modifier based on bishydroxyethyl tallow amine (Ethomeen T/12), the reaction product of polyisobutenyl succinic anhydride and an ethylene polyamine, and Ethomeen C/15.

US-A-2 151 300 relates to lubricating oil compositions containing a major portion of a mineral lubricating oil, a minor portion of an organic phosphite such as triphenyl phosphite and a minor amount, sufficient to provide substantial stability to the phosphorus compound, of an oil-soluble organic amine.

US-A-4 634 543 relates to a fluid composition for use in a shock absorber. The fluid composition comprises a base lubricating oil, a boron-containing compound and a phosphoric acid ester and/or ester of phosphorous acid, such as diphenyl hydrogen phosphite.

US-A-3 645 886 relates to the concept of reducing or preventing contamination of process equipment in the petroleum or chemical industry, wherein an organic feedstock is heat exchanged at a temperature of about 200 to about 1300°F (about 90 to about 700°C), and to the organic feedstock is added a mixture of a fatty acid ester of an alkanolamine and a mono-, di- or tri(organic) Phosphite ester is added. The tri(organic) phosphite esters may include triphenyl phosphite.

US-A-3 484 375 discloses the preparation of additives for lubricating oils, middle distillate fuels, residual fuels or reduced crude oils to improve their resistance to oxidation and sludge formation, to improve the viscosity index or to improve their flowability and pour point characteristics. The additives were prepared by reacting an organic phosphite ester with an alkaline polyamine or amino alcohol. The preferred organic phosphite esters contain at least one hydroxyl group bonded to the phosphorus, but they may also include triphenyl phosphite.

US-A-4 170 560 discloses additive compositions for use in crankcase lubricating oils comprising a mixture of an oil-soluble antioxidant and an oil-soluble hydroxylamine, including both the Ethomeene and the Ethoduomeene (sold by the Armak Company, part of Akzona, Inc.).

US-A-4 529 528 discloses the reaction product of, for example, an ethomeene, a dialkyl phosphite and a boron compound.

US-A-4 382 006 discloses a lubricant composition comprising a friction reducing amount of a borated adduct of compounds including the ethomeenes.

US-A-2 917 160 discloses the use of certain hydroxylated tertiary amines, including the ethomeenes, as anti-corrosive surface-active lubricants for metalworking. The amines can be used in the form of a salt. Phosphoric acid salts are given as examples.

US-A-3 186 946 discloses cutting fluids in which the active lubricating component is a borate salt of a tertiary amine including both the ethomeenes and the ethoduomeenes.

US-A-4 557 845 discloses the reaction product of an ethomeene with a di(C₁- to C₆-hydrocarbon)phosphite. The Reaction product is formed at a temperature between about 80 and 280°C and at reactant proportions such that about 5 to 100% of the antihydroxy groups are reacted with the phosphite.

US-A-3 509 052 relates to lubricant compositions containing a lubricating oil, a dispersant which is a derivative of a substituted succinic acid and a demulsifier. The demulsifier may comprise, for example, an ethomeene, but the preferred demulsifiers are polyoxyalkylene polyols and derivatives thereof.

US-A-3 394 179 discloses an oil-soluble lubricant additive which is the reaction product of a phosphosulfurized hydrocarbon and an amide formed by reacting an aliphatic polyamine with a high molecular weight monocarboxylic acid. The phosphosulfurized hydrocarbon is formed by reacting a terpene, a petroleum fraction or a polymer of a C2 to C6 olefin with a phosphorus sulfide.

US-A-2 805 217 relates to condensation products of terpenes with phosphorus sesquisulfide and oxygen. The condensation products are used in lubricating oil compositions as antioxidants and detergents.

US-A-3 511 780 relates to an additive useful as a sludge dispersant, anti-wear agent, antioxidant and preventive agent against harmful deposit formation in hydrocarbon compositions including fuel oils or lubricants. The additive is prepared by condensation of an alkenyl succinic anhydride with an aliphatic polyamine or with an aliphatic polyamine and a carboxylic acid, followed by further reaction of the condensation product with a phosphosulfurized hydrocarbon and with a dialkyldithiophosphoric acid. An example of a suitable phosphosulfurized hydrocarbon is given by polyisobutylene treated with P₂S₅.

US-A-3 850 822 discloses a lubricating oil for an internal combustion engine which contains a major part of oil and a minor part an additive package including a dispersant, a phosphosulfurized olefinic hydrocarbon and a phosphothionyl disulfide of phenol or a C1 to C18 alkylphenol. In one embodiment, the dispersant is prepared by reacting a polyisobutenyl succinic anhydride with a tetraethylenepentamine, the phosphosulfurized olefinic hydrocarbon is prepared by reacting P2S5 with α-pinene and the phosphothionyl disulfide is that of a nonylphenol.

US-A-4,557,845 discloses that the products of the reaction between a 2-hydroxyethyl alkylamine or certain higher oxylated members and a dihydrocarbon phosphite compound are effective friction modifiers and fuel economy additives for internal combustion engines when such products are combined with lubricants and liquid fuels. A similar disclosure is contained in US-A-4,529,528 except that the products are prepared by reacting a bis(2-hydroxyethyl)alkylamine, a dihydrocarbon phosphite and a boron compound.

US-A-3 175 976 relates to automatic transmission fluids with improved high temperature stability. The fluids contain a light oil in combination with a di(tert-butyl)phenol, a zinc dialkyldithiophosphate and an alkyl methacrylate-vinylpyrrolidone copolymer.

US-A-3 933 659 relates to extended life functional fluids useful in automatic transmissions. The functional fluids of this patent comprise a major amount of an oil of lubricating oil viscosity and an effective amount of an alkenyl succinimide, a Group II metal salt of a dihydrocarbyl dithiophosphoric acid, a basic sulfurized alkaline earth metal alkyl phenolate, and a compound selected from the group consisting of (a) fatty acid esters of dihydric or other polyhydric alcohols and oil-soluble oxyalkylated derivatives thereof, (b) fatty acid amides of low molecular weight amino acids, (c) N-fatty alkyl-N,N-diethanolamines, (d) N-fatty alkyl-N,N-di(ethoxyethanol)amines, (e) N- Fatty alkyl-N,N-di(polyethoxy)ethanolamines and (f) mixtures thereof.

US-A-4 010 106 relates to a functional fluid useful in automatic transmissions and an oil of lubricating oil viscosity and comprising an effective amount of each of an alkenyl succinimide, a Group II metal salt of a dihydrocarbyl dithiophosphoric acid, a friction modifier, a basic sulfurized alkaline earth metal alkyl phenolate, and a chlorinated olefin having about 15 to 50 carbon atoms, 20 to 60 weight percent chlorine and a boiling point of at least about 300°F (about 150°C). Among the friction modifiers that can be used in the functional fluid, fatty acid esters of a polyhydric alcohol or oil-soluble, oxyalkylated derivatives thereof, fatty acid amides of low molecular weight amino acids, N-fatty alkyl-N,N-diethanolamine, N-fatty alkyl-N,N-di(ethoxyethanol)amine, N-fatty alkyl-N,N-di(polyethoxy)ethanolamine or mixtures thereof are mentioned.

US-A-4 208 293 discloses lubricating oil compositions adapted for use as crankcase lubricants in internal combustion engines containing a friction reducing amount of a fatty acid amide or ester of diethanolamine. The compositions show improved results when they contain a zinc dihydrocarbyl dithiophosphate. Other additives may be included in the compositions and among the additives mentioned in this patent are alkaline earth metal phenolates and sulfurized phenolates, alkaline earth metal hydrocarbyl sulfonates, phosphosulfurized terpenes and polyolefins and their alkaline earth metal salts, polyalkyl methacrylates or ethylene-propylene copolymers, ethylene-propylene (non-conjugated diene) copolymers and 4,4'-methylenebis (2,6-di-tert-butylphenol).

US-A-4 474 674 discloses the use of diethanolamides or diisopropanolamides of alkylthioglycolic acids or boron, phosphorus or metal reaction products thereof as multifunctional additives for power transmission fluids such as automatic transmission fluids. These additives provide antioxidant, H₂S suppression, anti-corrosion and friction modification properties.

US-A-2 806 022 discloses neutralizing the reaction product of a phosphorus sulfide and a hydrocarbon with a basic metal compound. The neutralized products are used as lubricant additives in the manufacture of lubricants for internal combustion engines.

US-A-2 316 080 relates to lubricants for use in internal combustion engines such as automobile and diesel engines under more severe conditions where corrosion, piston ring seizing, cylinder wear and carbon and/or varnish formation can occur. The lubricants comprise a lubricating oil and a small amount of a neutralized or partially neutralized reaction product of a phosphorus sulfide and a mono-olefinic hydrocarbon polymer. This neutralized or partially neutralized product or metal derivative thereof can be used alone or in combination with the unneutralized reaction product of phosphorus sulfide and olefin polymer in lubricating oils. The neutralization of the reaction product of phosphorus sulfide and olefin polymer can be effected by adding the reaction product to a suitable alkaline compound, such as a hydroxide, a carbonate or an oxide of an alkali or alkaline earth metal and preferably potassium hydroxide. Ammonia or alkyl or aryl substituted ammonia such as amines may be used. Similar disclosures are contained in U.S. Patent Nos. 2,316,082 and 2,316,088.

US-A-3 034 907 discloses material compositions which are effective agents for preventing or delaying the formation of rust on iron surfaces and the formation of ice in the intake system of combustion systems. The compositions are characterized by a content of (a) a hydrophobic organic carrier, (b) a carboxamide monocarboxylic acid and (c) at least an equivalent amount of a hydroxyalkylated nitrogen base which contains at least one lipophilic radical. The hydroxyalkylated nitrogen base corresponds to the general formula:

where L represents a lipophilic radical as defined above, X represents a bridge member which is bonded to the nitrogen atom via an aliphatic carbon atom and is selected from the group consisting of lower -O-alkylene, -S-alkylene, -O-hydroxyalkylene, -S-hydroxyalkylene and alkylen

where R' is hydrogen, lower alkyl or lower hydroxyalkyl, -CO-O-alkylene and -CO-O-hydroxyalkylene radicals. In the above formulas, n is the integer 0 or 1, R₁ is hydrogen, lower alkyl or lower hydroxyalkyl or lower aminoalkyl radical, and R₂ is the same as (L-Xn) and R₁. In all cases, at least one of X, R₁ and R₂ is a lower hydroxyalkylated aliphatic radical.

US-A-3 235 501 relates to oil compositions containing a surfactant to promote foam formation, a silicone polymer antifoam agent and a minor amount of an antifoam oxylated aliphatic polyalkylamine. The oxylated aliphatic polyalkylamines correspond to one of the following formulas "a" or "b" depending on whether the amine from which they are made is a mono- or diamine:

wherein R is an aliphatic radical of about 4 to about 24 carbon atoms, -R'O- is an alkylene oxide radical selected from the group consisting of ethylene oxide and propylene oxide radicals, n an integer from 1 to about 25 and X is selected from hydrogen, R and -(R'O)₂H radicals, the total value of n in each case not being greater than 25, and

wherein R" is an aliphatic radical having 2 to about 6 carbon atoms, R'O, n and X are defined in formula "a" but at least one X is an R radical, and the total value of n in each case is not greater than about 25. Among the surfactants disclosed in the patent are the oil-soluble metal salts of high molecular weight (300 to 1,000) sulfonic acids such as petroleum-derived sulfonic acids and synthetic alkyl-arylsulfonic acids having from about 8 to about 24 carbon atoms in their alkyl moiety, the normal or basic (complex or overbased) barium or calcium sulfonate salts, the metal salts of alkylphenol sulfides such as the normal or basic (complex) barium or calcium salts of amyl or nonyl substituted phenol sulfides and the metal salts of reaction products of phosphorus sulfide and hydrocarbons. Specific salts of this type are the metal salts of phosphosulfurized polyolefins, such as the barium salts of the reaction product of P₂S₅ and polypropylene. Salts of this type are fully described, for example, in the above-discussed U.S. Patent Nos. 2,316,080, 2,316,082, 2,316,088 and 2,806,022.

US-A-4 664 826 relates to metal salt esters of hydrocarbon-substituted succinic acid or its anhydride, such as octadecenyl succinic anhydride and alkanols, such as thiobisethanol, which are capable of exhibiting friction modification, oxidation protection and corrosion protection properties in power transmission fluids, such as automatic transmission fluids.

US-A-4 704 217 relates to a gasoline crankcase lubricant which contains as friction modifier a dialkoxylated alkylpolyoxyalkylamine with the formula

wherein R is a (C₁-C₂₀)hydrocarbon radical, R' and R' are divalent (C₁-C₁₀)alkylene groups, a is an integer from about 1 to about 10, and x+y is a value from about 1 to about 20.

The present invention is based in part on the discovery that certain hydroxyetheramine compounds possess friction modifier properties and that they are compatible with other conventional additives. The hydroxyetheramine friction modifiers used in the present invention are stable and therefore do not adversely affect the friction stability of the base oils in which they are contained. In short, the hydroxyetheramine friction modifiers used in the present invention have been found to be a desirable additive for use in oleaginous or oil-containing compositions, particularly in power transmission fluids and more particularly in automatic transmission fluids.

The present invention provides a power transmission fluid that

(a) a natural or synthetic base oil;

(b) a friction-modifying amount of a borated or non-borated hydroxyetheramine compound having the formula

in which X is O or S, R₁ is a straight-chain or branched-chain, saturated or unsaturated, aliphatic C₃ to C₂₇ hydrocarbon radical, R₂ is a straight-chain or branched-chain C₁ to C₆ alkylene radical, R₃ is H or CH₃, R₄ and R₅ are independently straight-chain or branched-chain C₂ to C₅ alkylene radicals and p and p' independently represent 1 to 4, wherein the hydroxyetheramine compound has a total of 10 to 30 carbon atoms;

(c) an amount effective to impart anti-wear properties to the fluid of an organic phosphite ester having the formula

in which R₆ is a hydrocarbon radical selected from the group consisting of aryl and C₁ to C₃-alkaryl and R₇ and R₄ independently are a hydrocarbon radical selected from the group consisting of aryl, C₁ to C₂₅-alkyl, C₁ to C₃-alkaryl, C₅ to C₈-cycloalkyl and halogen-substituted derivatives thereof, and

(d) at least one additional compound in an amount effective to impart to the fluid at least one of antioxidant activity, seal swelling, dispersibility and viscosity change properties.

The invention also provides the use for changing the frictional properties of a natural or synthetic base oil useful as a power transmission fluid, from

(i) a borated or non-borated hydroxyetheramine compound as defined in (b) above, together with

(ii) an organic phosphite ester as defined in (c) above, together with

(iii) at least one additional compound in an amount effective to impart to the fluid at least one of antioxidation, seal swelling, dispersibility and viscosity change properties.

The invention also provides an additive concentrate for incorporation into a natural or synthetic base oil to produce a power transmission fluid, the concentrate

(i) an oil solution of a borated or non-borated hydroxyetheramine compound as defined in (b) above;

(ii) an organic phosphite ester as defined in (c) above; and

(iii) at least one additional compound to impart to the liquid at least one of the properties of antioxidant action, seal swelling, dispersibility and viscosity change.

According to the invention, the base oil is advantageously a mineral oil and the power transmission fluid is advantageously an automatic transmission fluid. The hydroxyetheramine used according to the invention, when combined with other conventional additives, is particularly suitable for meeting the stringent ATF requirements from the standpoint of adequately balancing anti-wear, static and dynamic friction coefficients, friction change and stability, dispersibility, sludge inhibition, anti-oxidation and corrosion resistance properties.

According to the invention, the hydroxyetheramine friction modifier compounds described above are used together with an organic phosphite ester, preferably a triarylphosphite antiwear material, for example triphenylphosphite.

The hydroxyetheramine friction modifier compounds can be used in the form of a borated reaction product of the hydroxyetheramine compound with a boron compound such as boric acid or a C1 to C4 trialkyl borate.

The present invention makes it possible to improve the static and dynamic friction coefficients and the friction stability properties of a lubricating oil composition adapted for use as a power transmission fluid.

The hydroxyetheramine friction modifier additives according to the invention can be represented by the structural formula

in which R₁ is a straight-chain or branched-chain, saturated or unsaturated, aliphatic C₃ to C₂₇-hydrocarbon radical (preferably straight-chain alkylene), preferably C₁₀ to C₂₀ and most preferably C₁₆ to C₂₇; R₂ is a straight-chain or branched-chain C₁₀ to C₆-alkylene radical (preferably straight-chain alkylene), typically C₂ to C₆, preferably C₂ to C₄ and most preferably C₃-alkylene; R₃ is H or CH₃, preferably H; R₄ and R₅, which may be the same or different, independently represent a straight chain or branched chain C₂ to C₅ alkylene radical (preferably straight chain alkylene radical), preferably C₂ alkylene; and p and p' independently represent 1 to 4, wherein the hydroxyetheramine compounds have a combined total of 10 to 30 carbon atoms. Preferably, X represents oxygen and R₂, R₄ and R₅ represent straight chain alkylene radicals. In a particularly preferred embodiment, X represents oxygen, R₁ and R₃ contain a combined total of 18 carbon atoms, R₂ represents C₃ alkylene and R₄ and R₅ are each C₂ alkylene.

When X is oxygen, the hydroxyetheramine compound can be prepared, for example, by a multi-step process in which an alkanol is first reacted with an unsaturated nitrile such as acrylonitrile in the presence of an initiator to form an ethernitrile intermediate. The intermediate is then hydrogenated, preferably in the presence of a conventional hydrogenation catalyst such as Raney nickel, to form an etheramine. The etheramine is then reacted with an alkylene oxide such as ethylene oxide in the presence of an alkaline catalyst by a conventional process at a temperature in the range of about 90 to 150°C. The overall process for preparing the desired hydroxyetheramine compounds is described, for example, in US-A-3 255 253 and can be illustrated by the following equations: Equation catalyst

where R and R' are straight-chain or branched-chain alkyl radicals.

When X is S, the hydroxyetheramine friction modifier compounds can be formed, for example, by effecting a conventional free radical reaction between a long chain alpha-olefin and a hydroxyalkyl mercaptan, such as a beta-hydroxyethyl mercaptan, to produce a long chain alkyl hydroxyalkyl sulfide. The long chain alkyl hydroxyalkyl sulfide is then mixed with thionyl chloride at low temperature and thereafter heated to about 40°C to form a long chain alkyl chloroalkyl sulfide. The long chain alkyl chloroalkyl sulfide is then caused to react with a dialkanolamine, such as diethanolamine, and if desired, with an alkylene oxide, such as ethylene oxide, in the presence of an alkaline catalyst and at a temperature on the order of about 100°C to form the desired hydroxyetheramine compounds. Methods of the above type are known in the art and are discussed, for example, in US-A-3,705,139, the disclosure of which is incorporated herein by reference.

The hydroxyetheramine compounds can be used as such. However, they can also be used in the form of an adduct or reaction product with a boron compound, such as boron oxide and the metaborates, boric acid or a mono-, di- or trihydrocarbon borate, e.g. trialkyl borate.

Such adducts or derivatives can be illustrated, for example, by the following structural formula:

wherein R₁, R₂, R₃, R₄, R₅, p and p' are the same as defined above and R' is either hydrogen or an alkyl group.

Representative examples of alkyl borates that can be used to borate the alkanolamine compounds include mono-, di-, or tributyl borates, mono-, di-, or trihexyl borates, and the like. The borate adducts can be prepared simply by heating a mixture of the hydroxyetheramine compound and the boron compound, preferably in the presence of a suitable solvent or solvents, at a temperature on the order of about 100°C to about 280°C for a period of about 1 to 2 hours to about 15 hours. The boration levels can vary widely, for example, over a range of about 1.0 to about 5.0 weight percent. Such boration processes are well known in the art and are described, for example, in the U.S. Patent Nos. 4,529,528, 4,594,171 and 4,382,006, the disclosures of which are incorporated herein by reference.

As indicated above, the hydroxyetheramine friction modifiers used in the present invention are used in oil-containing or oleaginous compositions which also contain organic phosphite esters as anti-wear additives. The organic phosphite esters which can be used can be represented by the formula

wherein R6 is a hydrocarbon radical selected from the group consisting of aryl and C1 to C3 alkaryl and R7 and R8 are the same or different hydrocarbon radicals selected from the group consisting of aryl, C1 to C25, preferably C6 to C20 and most preferably C8 to C18 alkyl, C1 to C3 alkaryl, C5 to C8 cycloalkyl and halogen-substituted derivatives thereof.

Representative examples of suitable R6, R7 and R8 groups of formula III include octyl, nonyl, decyl, dodecyl, hexyl, octadecyl and phenyl, with the phenyl group being most preferred.

In most cases it is preferred that R₆, R₇ and R₈ are the same.

The organic phosphite esters can be obtained by the direct esterification of phosphoric acid or a phosphorus trihalide with a phenol or an alcohol or a mixture thereof. Processes for preparing the organic phosphite esters are known in the art and are discussed, for example, in US-A-3,513,093, the disclosures of which are incorporated herein by reference.

It has been found that the combination of the organic phosphite esters and the hydroxyetheramine compounds of the invention has multifunctional properties including Has anti-wear, friction change, friction stability and copper corrosion resistance properties.

Accordingly, the hydroxyetheramine friction modifier compounds are used in combination with the organic phosphite ester compounds by incorporation and dissolution or dispersion in an oleaginous or oily material to provide power transmission fluids, for example, automatic transmission fluids.

The present combination of additives finds use in power transmission fluids that utilize a base oil in which the additive or additives are dissolved or dispersed.

Such base oils can be natural or synthetic, although natural base oils provide greater benefit.

Thus, base oils suitable for use in the preparation of power transmission fluids according to the invention include those conventionally used in power transmission fluids such as automatic transmission fluids, tractor fluids, general purpose tractor fluids and hydraulic fluids, heavy duty hydraulic fluids, power steering fluids and the like.

Thus, the additives of the invention can be suitably incorporated into synthetic base oils such as alkyl esters of dicarboxylic acids, polyglycols and alcohols; poly-α-olefins, alkylbenzenes, organic esters of phosphoric acids and polysilicone oil.

Natural base oils include mineral lubricating oils, which can vary widely in the nature of their crude oil source, e.g., paraffinic, naphthenic, mixed paraffinic-naphthenic, and the like, as well as their formation, e.g., distillation range, straight run or cracked, hydrofined, solvent extracted, and the like.

More specifically, the natural lubricating oil bases that can be used in the compositions of the invention can be directly produced mineral lubricating oils or distillates obtained from paraffinic, naphthenic, asphaltic or mixed base crude oils, or, if desired, various blended oils as well as residues, particularly those from which asphaltic components have been removed. The oils may be refined by conventional processes using acid, alkali and/or bleaching earth or other agents such as aluminium chloride, or they may be extraction oils, for example, obtained by solvent extraction with solvents of the type phenol, sulphur dioxide, furfural, dichlorodiethyl ether, nitrobenzene, crotonaldehyde, etc.

The lubricating oil bases typically have a viscosity of about 2.5 to about 12, and preferably about 3.5 to about 9 mm²/s (cSt) at 100ºC.

The additives of the present invention can be used in a power transmission fluid comprising lubricating oil, typically in a major amount, and the additives, typically in a minor amount, effective to impart increased frictional variance, antiwear and frictional stability properties relative to the absence of the additives. Additional conventional additives selected to meet the particular requirements of a chosen type of power transmission fluid can be included if desired.

The additive materials of the invention are oil-soluble, soluble in oil with the aid of a suitable solvent or stably dispersible materials. Oil-soluble, soluble or stably dispersible in the terminology used herein does not necessarily mean that the materials are soluble, soluble, miscible or suspendable in oil in any proportions. It does mean, however, that the respective additives are soluble in oil or stably dispersible to an extent that they exert their intended effect in the environment in which the oil is used. In addition, the incorporation of an additional dispersant and/or other additives may require the incorporation of larger proportions of a particular organic phosphite ester or particular hydroxyetheramine compound, if desired.

The additives of the invention can be incorporated into the lubricating oil in any suitable manner. They can thus be added directly to the oil by dispersing them or by dissolving them in the oil to the desired concentration, typically with the aid of a suitable solvent, such as mineral oil. Such mixing can take place at room temperature or elevated temperature. Alternatively, the additive combination of organic phosphite ester and hydroxyetheramine can be mixed with a suitable oil-soluble solvent and base oil to form a concentrate which can then be mixed with a lubricating oil base to form the final formulation.

The lubricating oil base for the additives of the invention is typically adapted to form lubricating oil compositions (i.e., formulations) by incorporating additives to achieve specific functions.

As indicated above, a broad class of lubricating oil compositions suitable in conjunction with the additives of the present invention are power steering fluids, tractor fluids, general purpose tractor oils, and the like.

The benefits of the additives of the invention are particularly significant when used in a lubricating oil adapted for use as an automatic transmission fluid.

Power transmission fluids, such as automatic transmission fluids, as well as lubricating oils in general, are typically composed of a number of additives, each of which is useful for improving the chemical and/or physical properties of the oil or fluid. The additives are usually sold as a concentrate package in which mineral oil or another base oil is present. The mineral lubricating oil in automatic transmission fluids is a refined hydrocarbon oil or a blend of refined hydrocarbon oils selected according to the viscosity requirements of the particular fluids, but typically have a viscosity range of 2.5 to 9, e.g. 3.5 to 9 cSt or mm²/s at 100ºC. Suitable base oils include a wide variety of light hydrocarbon mineral oils such as naphthenic base oils, paraffin base oils and blends thereof.

Representative additives typically present in such packages as well as in the final formulations include viscosity index (VI) improvers, corrosion inhibitors, oxidation inhibitors, friction agents, lubricating oil flow improvers, dispersants, antifoam agents, anti-clogging agents, detergents, metal rust inhibitors and seal swelling agents.

Viscosity modifiers provide the lubricating oil with high and low temperature operability, allowing it to remain shear stable at elevated temperatures and exhibit acceptable viscosity or fluidity at low temperatures.

VI improvers are generally high molecular weight hydrocarbon polymers or, more preferably, polyesters. The VI improvers may also be derivatized to include additional properties or functions, such as additional dispersing properties.

These oil-soluble VI polymers generally have average molecular weights of 10³ to 10⁶, preferably 10⁴ to 10⁶, e.g. 20,000 to 250,000, as determined by gel permeation chromatography or membrane osmometry.

Examples of suitable hydrocarbon polymers include homopolymers and copolymers of two or more monomers of C2 to C30, e.g. C2 to C8, olefins, including both α-olefins and internal olefins, which may be straight chain or branched, aliphatic, aromatic, alkyl aromatic, cycloaliphatic, etc. Often they are copolymers of ethylene with C3 to C30 olefins, particularly preferred are the copolymers of ethylene and propylene. Other polymers may be used, such as polyisobutylenes, homopolymers and copolymers of C6 and higher α-olefins, atactic polypropylene, hydrogenated polymers and copolymers and terpolymers of styrene, e.g. B. with isoprene and/or butadiene.

More specifically, other hydrocarbon polymers suitable as viscosity index improvers include those which can be described as hydrogenated or partially hydrogenated homopolymers, and random, graded, star or block interpolymers (including terpolymers, tetrapolymers, etc.) of conjugated dienes and/or monovinyl aromatic compounds with optionally α-olefins or lower alkenes, e.g., C3 to C18 α-olefins or lower alkenes. The conjugated dienes include isoprene, butadiene, 2,3-dimethylbutadiene, piperylene and/or mixtures thereof, such as mixtures of isoprene and butadiene. The monovinyl aromatic compounds include vinyl di- or polyaromatic compounds, e.g., C3 to C18 α-olefins or lower alkenes. B. vinylnaphthalene, or mixtures of vinyl mono-, di- or polyaromatic compounds, but are preferably monovinyl-monoaromatic compounds such as styrene or alkylated styrenes substituted on the α-carbon atoms of the styrene, such as α-methylstyrene, or substituted on ring carbon atoms, such as o-, m-, p-methylstyrene, ethylstyrene, propylstyrene, isopropylstyrene, butylstyrene, isobutylstyrene, tert-butylstyrene (e.g. p-tert-butylstyrene). Also included are vinylxylenes, methylethylstyrenes and ethylvinylstyrenes. Alpha-olefins and lower alkenes optionally included in these random, graded and block copolymers preferably include ethylene, propylene, butene, ethylene-propylene copolymers, isobutylene, and polymers and copolymers thereof. Additionally, as is known in the art, these random, graded and block copolymers may include relatively small amounts, i.e., less than about 5 mole percent, of other copolymerizable monomers such as vinylpyridines, vinyllactams, methacrylates, vinyl chloride, vinylidene chloride, vinyl acetate, vinyl stearate, and the like.

Specific examples include random polymers of butadiene and/or isoprene and polymers of isoprene and/or butadiene and styrene. Typical block copolymers include polystyrene-polyisoprene, polystyrene-polybutadiene, polystyrene-polyethylene, polystyrene-ethylene/propylene copolymer, polyvinylcyclohexane-hydrogenated polyisoprene and polyvinylcyclohexane hydrogenated polybutadiene. Graded polymers include those from the aforementioned monomers prepared by methods known in the art. Star polymers typically comprise a core and polymeric arms attached to the core, the arms consisting of a homopolymer or interpolymer of the aforementioned conjugated diene and/or monovinyl aromatic monomers. Typically, at least about 80% of the aliphatic unsaturation and about 20% of the aromatic unsaturation of the star polymer is reduced by hydrogenation.

Representative examples of patents disclosing such hydrogenated polymers or interpolymers include U.S. Patent Nos. 3,312,621; 3,318,813; 3,630,905; 3,668,125; 3,763,044; 3,795,615; 3,835,053; 3,838,049; 3,965,019; 4,358,565 and 4,557,849, the disclosures of which are incorporated herein by reference.

The molecular weight of the polymer may have been reduced, for example, by mastication, extrusion, oxidation or thermal degradation, and it may have been oxidized and contain oxygen. Also included are derivatized polymers, such as interpolymers of ethylene/propylene subsequently grafted with an active monomer such as maleic anhydride, which may have been further reacted with an alcohol or amine, e.g. an alkylene polyamine or hydroxyamine, e.g. see U.S. Patent Nos. 4,089,794; 4,160,739; 4,137,185; or copolymers of ethylene and propylene which may have been reacted or grafted with nitrogen compounds as shown in U.S. Patent Nos. 4,068,056, 4,068,058, 4,146,489 and 4,149,984.

Suitable hydrocarbon polymers are ethylene interpolymers containing 15 to 90 wt.% ethylene, preferably 30 to 80 wt.% ethylene and 10 to 85 wt.%, preferably 20 to 70 wt.% of one or more C₃ to C₂₃, preferably C₃ to C₁₈ and especially C₃ to C₈ α-olefins. Although not necessary, such copolymers preferably have a degree of crystallinity of less than 25 wt.%, as determined by X-ray spectroscopy and differential scanning calorimetry. Copolymers of ethylene and propylene are most preferred. Other alpha-olefins which are suitable in place of the propylene to form the copolymer or which can be used in combination with ethylene and propylene to form a terpolymer, tetrapolymer, etc. include 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, etc.; also branched chain alpha-olefins such as 4-methyl-1-pentene, 4-methyl-1-hexene, 5-methylpentene-1, 4,4-dimethyl-1-pentene and 6-methylheptene-1, etc. and mixtures thereof.

Terpolymers, tetrapolymers, etc. of ethylene, the C3-28 alpha-olefin and a non-conjugated diolefin or mixtures of such diolefins may also be used. The amount of non-conjugated diolefin generally ranges from about 0.5 to 20 mole percent, preferably from about 1 to about 7 mole percent, based on the total amount of ethylene and alpha-olefin present.

The preferred VI improvers are polyesters, most preferably polyesters of ethylenically unsaturated C3 to C8 mono- and dicarboxylic acids, such as methacrylic and acrylic acid, maleic acid, maleic anhydride, fumaric acid, etc.

Examples of unsaturated esters that can be used include those of aliphatic saturated monoalcohols having at least one carbon atom, and preferably 12 to 20 carbon atoms, such as decyl acrylate, lauryl methacrylate, cetyl methacrylate, stearyl methacrylate, and the like, and mixtures thereof.

Other esters include the vinyl alcohol esters of C2 to C22 fatty or monocarboxylic acids, preferably saturated acids, such as vinyl acetate, vinyl laurate, vinyl palmitate, vinyl stearate, vinyl oleate and the like, and mixtures thereof. Copolymers of vinyl alcohol esters with unsaturated acid esters, such as the copolymer of vinyl acetate with dialkyl fumarates, can also be used.

The esters can be copolymerized with other unsaturated monomers such as olefins, e.g. 0.2 to 5 moles of aliphatic or aromatic C₂- to C₂₀-olefin per mole of unsaturated ester or per mole of unsaturated acid or anhydride, followed by esterification. For example, copolymers of styrene with maleic anhydride esterified with alcohols and amines are known, e.g. see US-A-3 702 300.

Such ester polymers may be grafted or copolymerized with polymerizable unsaturated nitrogen-containing monomers to impart dispersibility to the VI improvers. Examples of suitable unsaturated nitrogen-containing monomers for imparting dispersibility include those containing from 4 to 20 carbon atoms, such as the amino-substituted olefins such as p-(β-diethylaminoethyl)styrene, basic nitrogen-containing heterocycles having a polymerizable ethylenically unsaturated substituent, e.g. B. the vinylpyridines and the vinylalkylpyridines such as 2-vinyl-5-ethylpyridine, 2-methyl-5-vinylpyridine, 2-vinylpyridine, 3-vinylpyridine, 4-vinylpyridine, 3-methyl-5-vinylpyridine, 4-methyl-2-vinylpyridine, 4-ethyl-2-vinylpyridine and 2-butyl-5-vinylpyridine and the like.

N-vinyllactams are also suitable, e.g. N-vinylpyrrolidones or N-vinylpiperidones.

The vinylpyrrolidones are preferred and examples are N-vinylpyrrolidone, N-(1-methylvinyl)pyrrolidone, N-vinyl-5- methylpyrrolidone, N-vinyl-3,3-dimethylpyrrolidone, N-vinyl-5-ethylpyrrolidone, etc.

Corrosion inhibitors, also referred to as anticorrosives, reduce the degradation of non-ferrous metal parts contacted by the lubricating oil composition. Examples of corrosion inhibitors are phosphosulfurized hydrocarbons and the products obtained by reacting a phosphosulfurized hydrocarbon with an alkaline earth metal oxide or hydroxide, preferably in the presence of an alkylated phenol or an alkylphenol thioether and also preferably in the presence of carbon dioxide. As discussed above, phosphosulfurized hydrocarbons are prepared by reacting a suitable hydrocarbon such as a terpene, a heavy petroleum fraction of a C2 to C6 olefin polymer, such as polyisobutene, with 5 to 30 weight percent of a phosphorus sulfide for 1/2 to 15 hours at temperatures ranging from 150 to 400°F (about 65 to 205°C). Neutralization of the phosphosulfurized hydrocarbon can be accomplished by the manner taught in U.S. Patent 2,969,324.

Other suitable corrosion inhibitors include copper corrosion inhibitors comprising hydrocarbylthio-disubstituted derivatives of 1,3,4-thiadiazoles, e.g., C2 to C30 alkyl, aryl, cycloalkyl, aralkyl and alkaryl, mono-, di-, tri- or tetrathio-substituted derivatives thereof.

Representative examples of such materials include: 2,5-bis(octylthio)-1,3,4-thiadiazole; 2,5-bis(octyldithio)-1,3,4-thiadiazole; 2,5-bis(octyltrithio)-1,3,4-thiadiazole; 2,5-bis(octyltetrathio)-1,3,4-thiadiazole; 2,5-bis(nonylthio)-1,3,4-thiadiazole; 2,5-bis(dodecylthio)-1,3,4-thiadiazole; 2,5-bis(cyclohexyldithio)-1,3,4-thiadiazole; 2-dodecyldithio-5-phenyldithio-1,3,4-thiadiazole, and mixtures thereof.

Preferred copper corrosion inhibitors are the derivatives of 1,3,4-thiadiazoles such as those described in U.S. Patent Nos. 2,719,125, 2,719,126 and 3,087,932, particularly preferred is the compound 2,5-bis(t-octyldithio)-1,3,4-thiadiazole, commercially available as Amoco 150, and 2,5-bis(t-nonyldithio-1,3,4-thiadiazole, commercially available as Amoco 158.

The preparation of such materials is further described in U.S. Patent Nos. 2,719,125, 2,719,126, 3,087,932 and 4,410,436, the disclosures of which are incorporated herein by reference.

Antioxidants reduce the tendency of mineral oils to age during operation, whereby the ageing can be noticeable through oxidation products such as sludge or varnish-like deposits on the metal surfaces. Such Oxidation inhibitors include alkaline earth metal salts of alkylphenol thioethers having preferably C5 to C12 alkyl side chains, e.g. calcium nonylphenol sulfide, barium t-octylphenol sulfide; arylamines, e.g. dioctylphenylamine, phenyl-α-naphthylamine; phosphosulfurized or sulfurized hydrocarbons, etc.

Friction modifiers serve to impart the proper friction properties to an ATF as required by the automotive industry. In the present invention, the hydroxyetheramine compounds serve as the primary friction modifiers.

Dispersants keep oil-insoluble components, which are formed by oxidation during use, suspended in the liquid and thus prevent flocculation of sludge and precipitates. Suitable dispersants include, for example, dispersants of the ash-producing or ashless type, the latter type being preferred.

Examples of the ashless dispersants are the oil-soluble, neutral or basic salts of alkali or alkaline earth metals with sulfonic acids, carboxylic acids or organic phosphoric acids characterized by the presence of at least one direct carbon-to-phosphorus bond, such as those prepared by treating an olefin polymer (e.g. polyisobutene having a molecular weight of 1,000) with a phosphorizing agent such as phosphorus trichloride, phosphorus heptasulfide, phosphorus pentasulfide, phosphorus trichloride and sulfur, white phosphorus and a sulfur halide or phosphorus thiochloride. The most commonly used salts of such acids are those of sodium, potassium, lithium, calcium, magnesium, strontium and barium.

The term "basic salt" is used to refer to metal salts in which the metal is present in stoichiometrically greater amounts than the organic acid moiety. The commonly used methods for preparing the basic salts involve heating a mineral oil solution of an acid with a stoichiometric excess of a metal neutralizing agent, such as a metal oxide, hydroxide, carbonate, bicarbonate or sulfide, to a temperature of about 50°C and filtering the resulting mass. The use of an "accelerator" in the neutralization step to assist in the introduction of a larger excess of metal is also known. Examples of compounds useful as accelerators include phenolic substances such as phenol, naphthol, alkylphenol, thiophenol, sulfurized alkylphenol and condensation products of formaldehyde and a phenolic substance; alcohols such as methanol, 2-propanol, octyl alcohol, cellosolve, ethylene glycol, stearyl alcohol and cyclohexyl alcohol; and amines such as aniline, phenylenediamine, phenyl-β-naphthylamine and dodecylamine. A particularly effective method for preparing the basic salts comprises mixing an acid with an excess of a basic alkaline earth metal neutralizing agent and at least one alcohol accelerator, and carbonating the mixture at an elevated temperature, such as 60°C to 200°C. This class of substances is discussed further hereinafter in the context of detergents and metal rust inhibitors.

The most preferred ash-producing detergents include the metal salts of sulfonic acids, alkylphenols, sulfurized alkylphenols, alkyl salicylates, naphthenates and other oil-soluble mono- or dicarboxylic acids. Highly basic ("overbased") metal salts such as the highly basic alkaline earth metal sulfonates (particularly Ca and Mg salts) are often used as detergents. They are usually prepared by heating a mixture comprising an oil-soluble sulfonate or alkaryl sulfonic acid with an excess of alkaline earth metal compound in excess of that required to completely neutralize all of the sulfonic acid present, followed by forming a dispersed carbonate complex by reacting the excess metal with carbon dioxide to provide the necessary overbasicity. The sulfonic acids are typically obtained by the sulfonation of alkyl-substituted aromatic hydrocarbons, such as those obtained from petroleum fractionation by distillation and/or or extraction or by alkylation of aromatic hydrocarbons such as those obtained by alkylation of benzene, toluene, xylene, naphthalene, diphenyl and the halogen derivatives such as chlorobenzene, chlorotoluene and chloronaphthalene. The alkylation can be carried out in the presence of a catalyst with alkylating agents having from about 3 to more than 30 carbon atoms such as haloparaffins, olefins obtainable by dehydrogenation of paraffins, polyolefins such as polymers of ethylene, propylene, etc. The alkaryl sulfonates usually contain from about 9 to about 70 or more carbon atoms, preferably from about 16 to about 50 carbon atoms per alkyl-substituted aromatic group.

The alkaline earth metal compounds that can be used to neutralize these alkyl sulfonic acids to provide the sulfonates include the oxides and hydroxides, alkoxides, carbonates, carboxylates, sulfides, hydrogen sulfide, nitrates, borates and ethers of magnesium, calcium and barium. Examples are calcium oxide, calcium hydroxide, magnesium acetate and magnesium borate. As noted, the alkaline earth metal compound is used in excess of the amount required to completely neutralize the alkaryl sulfonic acids. Generally, the amount will range from about 100 to about 220%, although it is preferred to use at least 125% of the stoichiometric amount of metal required to completely neutralize.

Various other methods of preparing basic alkaline earth alkaryl sulfonates are known, such as those described in U.S. Patent Nos. 3,150,088 and 3,150,089, in which overbasicity is achieved by hydrolysis of an alkoxide-carbonate complex with the alkaryl sulfonate in a hydrocarbon solvent/diluent oil.

Ashless dispersants, which are the preferred dispersant for use in the context of the invention, are so designated despite the fact that, depending on their composition, they release a non-volatile material such as boric acid or phosphorus pentoxide; however, they do not usually contain any metal and therefore do not produce a metal-containing ash upon combustion. Many types of ashless dispersants are known in the art and all of them are suitable for use in the lubricant compositions of the invention. The following are exemplary:

1. Reaction products of carboxylic acids (or their derivatives) containing at least about 30 and preferably at least about 50 carbon atoms with nitrogen-containing compounds such as amine, organic hydroxy compounds such as phenols and alcohols and/or basic inorganic materials. Examples of these "carboxyl dispersants" are described, for example, in UK-A-1 306 529 and American Patent Nos. 3 272 746, 3 341 542, 3 454 607 and 4 654 403.

More specifically, nitrogen or ester containing ashless dispersants include members selected from the group consisting of oil soluble salts, amides, imides, oxazolines and esters, and mixtures thereof, of long chain hydrocarbon substituted mono- or dicarboxylic acids or anhydrides or esters derived therefrom, wherein the long chain hydrocarbon group is a polymer, typically of a C2 to C10, e.g., a C2 to C5 monoolefin, the polymer having a number average molecular weight of about 700 to 5,000.

The long chain hydrocarbon substituted dicarboxylic acid material which can be used to prepare the dispersants includes the reaction product of (i) C4 to C10 monounsaturated dicarboxylic acid in which (a) the carboxyl groups are vicinal, i.e. located on adjacent carbon atoms, and (b) at least one, preferably both of these adjacent carbon atoms are part of the monounsaturation; and (ii) derivatives of (i) such as anhydrides or C1 to C5 alcohol derived mono- or diesters of (i). By reaction with the hydrocarbon polymer, the monounsaturation of the dicarboxylic acid material is saturated. For example, maleic anhydride becomes a hydrocarbon-substituted succinic anhydride.

Typically, about 0.7 to about 4.0 (e.g., 0.8 to 2.6), preferably about 1.0 to about 2.0, and most preferably about 1.1 to about 1.7 moles of the C4 to C10 unsaturated dicarboxylic acid material are charged to the reactor per mole of polyolefin charged.

Normally, not all of the polyolefin reacts with the unsaturated acid or derivative, and the hydrocarbyl-substituted dicarboxylic acid material contains unreacted polyolefin. The unreacted polyolefin is typically not removed from the reaction mixture (because such removal would be difficult and uneconomical) and the product mixture, stripped of all unreacted C4 to C10 dicarboxylic acid material, is used for further reactions with the amine or alcohol as described below to prepare the dispersant.

The characterization of the average number of moles of dicarboxylic acid, anhydride or ester reacted per mole of polyolefin introduced into the reaction (whether it underwent the reaction or not) is defined herein as the functionality. The functionality is based on (i) determining the saponification number of the resulting product mixture using potassium hydroxide, and (ii) the number average molecular weight of the polymer introduced using methods known in the art. The functionality is defined only with respect to the resulting reaction product mixture. Although the amount of unreacted polyolefin contained in the reaction mixture may be subsequently changed, i.e., increased or decreased by techniques known in the art, such changes do not change the functionality defined above. The term hydrocarbyl-substituted dicarboxylic acid material is intended to refer to the reaction product mixture whether or not it has undergone these modifications.

Accordingly, the functionality of the hydrocarbyl-substituted dicarboxylic acid material is at least about 0.5, preferably at least about 0.8, more preferably at least about 0.9, and typically varies from about 0.5 to about 2.8 (e.g., 0.6 to 2), preferably about 0.8 to about 1.4, and more preferably about 0.9 to about 1.3.

Examples of such unsaturated dicarboxylic acids or anhydrides or esters thereof are fumaric acid, itaconic acid, maleic acid, maleic anhydride, chloromaleic acid, chloromaleic anhydride, acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, etc.

Preferred olefin polymers for reaction with the unsaturated dicarboxylic acids or derivatives thereof are polymers comprising a major molar amount of C2 to C10, e.g. C2 to C5, monoolefin. Such olefins include ethylene, propylene, butylene, isobutylene, pentene, octene-1, styrene, etc. The polymers can be both homopolymers such as polyisobutylene and copolymers of two or more such olefins such as copolymers of ethylene and propylene; butylene and isobutylene; propylene and isobutylene, etc. Other copolymers include those in which a minor molar amount of the copolymer monomers, e.g. B. 1 to 10 mol.%, is a non-conjugated C₄ to C₁₃ diolefin, e.g. a copolymer of isobutylene and butadiene or a copolymer of ethylene, propylene and 1,4-hexadiene, etc.

In some cases, the olefin polymer may be fully saturated, for example an ethylene-propylene copolymer prepared by a Ziegler-Natta synthesis using hydrogen as a retarder to control the molecular weight.

The olefin polymers used in dispersants typically have number average molecular weights within the range of about 700 to about 5,000, and more preferably between about 800 and about 3,000. Particularly useful olefin polymers have number average molecular weights within the range of about 900 to about 2,500 with approximately one terminal double bond per polymer chain. A A particularly useful starting material for highly potent dispersant additives is polyisobutylene. The number average molecular weight for such polymers can be determined by several known techniques. A convenient method for such a determination is by gel permeation chromatography (GPC), which additionally gives information on the molecular weight distribution, see WW Yau, JJ Kirkland and DD Bly, "Modern Size Exclusion Liquid Chromatography", John Wiley and Sons, New York, 1979.

Methods for reacting the olefin polymer with the unsaturated C4 to C10 dicarboxylic acid, anhydride or ester are known in the art. For example, the olefin polymer and dicarboxylic acid or derivative can simply be heated together as disclosed in U.S. Patent Nos. 3,361,673 and 3,401,118 to cause a thermal "ene" reaction to occur. Alternatively, the olefin polymer can first be halogenated, e.g., chlorinated or brominated, to about 1 to 8, preferably 3 to 7, weight percent based on the weight of the polymer by passing chlorine or bromine through the polyolefin for 0.5 to 10 hours, preferably 1 to 7 hours, at a temperature of 60 to 250°C, e.g., 120 to 160°C. The halogenated polymer can then be reacted with a sufficient amount of unsaturated acid or derivative for about 0.5 to 10 hours, e.g., 3 to 8 hours, at 100 to 250°C, usually about 180 to 235°C, so that the resulting product contains the desired number of moles of unsaturated acid or derivative per mole of halogenated polymer. Processes of this general type are taught in, among others, U.S. Patent Nos. 3,087,936, 3,172,892, and 3,272,746, and others.

Alternatively, the olefin polymer and the unsaturated acid or derivative are mixed and heated, with chlorine being added to the hot material. Processes of this type are described in U.S. Patent Nos. 3,215,707, 3,231,587, 3,912,764, 4,110,349, 4,234,435 and British Patent No. 1,440,219.

By using halogen, typically about 65 to 95 wt.% of the polyolefin, e.g. polyisobutylene, will react with the dicarboxylic acid or derivative. When conducting a thermal reaction without using halogen or a catalyst, typically only about 50 to 75 wt.% of the polyisobutene will react. Chlorination helps to increase the reactivity.

At least one hydrocarbyl substituted dicarboxylic acid material is mixed with at least one of amine, alcohol, including polyol, amino alcohol, etc. to give the dispersant additives. When the acid material is further reacted, e.g., neutralized, generally a major portion of at least 50% of the acid yielding units up to all of the acid units are reacted.

Amine compounds useful as nucleophilic reactants for neutralizing the hydrocarbyl-substituted dicarboxylic acid material include mono- and (preferably) polyamines, most preferably polyalkylenepolyamines having from about 2 to 60 and preferably 2 to 40 (e.g., 3 to 20) total carbon atoms and from about 1 to 12, preferably 3 to 12 and most preferably 3 to 9 nitrogen atoms in the molecule. These amines can be hydrocarbylamines or hydrocarbylamines that include additional groups, e.g., hydroxyl groups, alkoxy groups, amide groups, nitriles, imidazoline groups, and the like. Hydroxylamines having from 1 to 6 hydroxyl groups, preferably 1 to 3 hydroxyl groups, are particularly useful. Preferred amines are aliphatic, saturated amines including those having the general formulas

wherein R, R', R'' and R''' are independently selected from the group consisting of hydrogen; straight chain or branched C₁- to C₂₅-alkyl radicals, C₁- to C₁₂-alkoxy-C₂- to C₆-alkylene radicals, C₂- to C₁₂-hydroxyaminoalkylene radicals and C₁- to C₁₂-alkylamino- C₂- to C₆-alkylene radicals, and wherein R''' additionally represents a group having the formula

in which R' is as defined above and in which s and s' may be the same or a different number from 2 to 6 and preferably 2 to 4; and t and t' may be the same or different and are numbers from 0 to 10, preferably 2 to 7 and most preferably about 3 to 7, with the proviso that the sum of t and t' is not greater than 15. To ensure ease of reaction, it is preferred that R, R', R'', R''', s, s', t and t' are chosen in a manner sufficient to provide the compounds of formulas IV and V with typically at least one primary or secondary amine group, preferably at least two primary or secondary amine groups. This can be achieved by choosing hydrogen for at least one of the R, R', R'' or R''' groups or by allowing t in formula V to be at least one when R''' is H or when the VI group has a secondary amino group. The most preferred amines from the above formulas are represented by formula V and contain at least two primary amine groups and at least one and preferably at least three secondary amine groups.

Examples of suitable amine compounds include, but are not limited to: 1,2-diaminoethane; 1,3-diaminopropane; 1,4-diaminobutane; 1,6-diaminohexane; polyethyleneamines such as diethylenetriamine; triethylenetetramine; tetraethylenepentamine; polypropyleneamines such as 1,2-propylenediamine; di-(1,2-propylene)triamine; di-(1,3-propylene)triamine; N,N-dimethyl-1,3-diaminopropane; N,N-di-(2-aminoethyl)ethylenediamine; N,N-di(2-hydroxyethyl)-1,3-propylenediamine; 3-dodecyloxypropylamine; N-dodecyl-1,3-propanediamine; tris-hydroxymethylaminomethane (THAM); diisopropanolamine; diethanolamine; triethanolamine; mono-, di- and Tri(tallow)amines; aminomorpholines such as N-(3-aminopropyl)morpholine and mixtures thereof.

Other useful amine compounds include alicyclic diamines such as 1,4-di(aminomethyl)cyclohexane and heterocyclic nitrogen compounds such as imidazolines and N-aminoalkylpiperazines of the general formula:

where p₁ and P₂ are the same or different and are each integers from 1 to 4, and n₁, n₂ and n₃ are the same or different and are each integers from 1 to 3. Non-limiting examples of such amines include 2-pentadecylimidazoline; N-(2-aminoethyl)piperazine; etc. Commercially available mixtures of amine compounds can be advantageously used. For example, one process for preparing alkyleneamines uses the reaction of an alkylene dihalide (such as dichloroethylene or dichloropropylene) with ammonia, resulting in a complex mixture of alkyleneamines in which nitrogen pairs are joined by alkylene groups, resulting in the formation of such compounds as diethylenetriamine, triethylenetetramine, tetraethylenepentamine and the isomeric piperazines. Inexpensive poly(ethyleneamine) compounds containing an average of about 5 to 7 nitrogen atoms per molecule are available under trade names such as "Polyamine H", "Polyamine 400", "Dow Polyamine E-100", etc.

Useful amines also include polyoxyalkylenepolyamines such as those of the formulas, alkylen

where m has a value of about 3 to 70 and preferably 10 to 35, and alkylen

wherein n has a value of about 1 to 40, with the proviso that the sum of all n is about 3 to about 70, and preferably about 6 to about 35, and R is a polyvalent saturated hydrocarbon radical having up to 10 carbon atoms, the number of substituents of the R group being represented by "a" which is a number from 3 to 6. The alkylene groups in each of the formulas (VIII) or (IX) can be straight chain or branched chain and contain about 2 to 7, preferably about 2 to 4, carbon atoms.

The polyoxyalkylene polyamines of formulas (VIII) and (IX) above, preferably polyoxyalkylenediamines and polyoxyalkylenetriamines, can have average molecular weights in the range of about 200 to about 4,000, and preferably about 400 to about 2,000. The preferred polyoxyalkylene polyamines include the polyoxyethylene and the polyoxypropylenediamines and the polyoxypropylenetriamines having average molecular weights in the range of about 200 to 2,000. The polyoxyalkylene polyamines are commercially available and can be obtained, for example, from Jefferson Chemical Company, Inc., under the trade names "Jeffamines D-230, D-400, D-1000, D-2000, T-403", etc.

The amine is readily reacted with the selected hydrocarbyl-substituted dicarboxylic acid material, e.g., alkenyl succinic anhydride, by heating an oil solution containing 5 to 95 weight percent of the hydrocarbyl-substituted dicarboxylic acid material to about 100 to about 250°C, preferably 125 to 175°C, generally for 1 to 10 hours, e.g., 2 to 6 hours, until the desired amount of water is removed. The heating is preferably carried out to favor the formation of imides or mixtures of imides and amides over that of amides and salts. The reaction ratios of the hydrocarbyl-substituted dicarboxylic acid material to amine equivalents, as well as the other nucleophilic reactants described herein, can vary considerably depending upon the reactants and types of bonds formed. Generally, from 0.1 to 1.0, preferably from about 0.2 to 0.6, e.g., from 0.4 to 0.6 equivalents of dicarboxylic acid moiety content (e.g., substituted succinic anhydride content) is used per reactive equivalent of nucleophilic reactant, e.g., amine. For example, preferably about 0.8 moles of a pentamine (having two primary amino groups and five reactive nitrogen equivalents per molecule) is used to convert a composition having a functionality of 1.6 obtained from the reaction of a polyolefin with maleic anhydride to a mixture of amides and imides; e.g., B. Preferably, the pentamine is used in an amount sufficient to provide about 0.4 equivalents (i.e., 1.6 divided by (0.8 x 5) equivalents) of succinic anhydride units per reactive nitrogen equivalent of the amine.

The ashless dispersant esters are derived from the reaction of the above long chain hydrocarbon substituted dicarboxylic acid material and hydroxy compounds such as monohydric and polyhydric alcohols or aromatic compounds such as phenols or naphthols, etc. The polyhydric alcohols are the most preferred hydroxy compound and preferably contain from 2 to about 10 hydroxy radicals, for example, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol and other alkylene glycols in which the alkylene radical contains from 2 to about 8 carbon atoms. Other useful polyhydric alcohols include glycerin, glycerin monooleate, glycerin monostearate, glycerin monomethyl ether, pentaerythritol, dipentaerythritol and mixtures thereof. The ester dispersant may also be derived from unsaturated alcohols such as allyl alcohol, cinnamyl alcohol, propargyl alcohol, 1-cyclohexen-3-ol and oleyl alcohol. Still other classes of alcohols capable of dispersing the inventive Esters include the ether alcohols and amino alcohols including, for example, the oxyalkylene, oxyarylene, aminoalkylene and aminoarylene substituted alcohols having one or more oxyalkylene, oxyarylene, aminoalkylene and aminoarylene radicals. Examples include Cellosolve, Carbitol, N,N,N',N'-tetrahydroxytrimethylenediamine and ether alcohols having up to about 150 oxyalkylene radicals in which the alkylene radical contains from 1 to about 8 carbon atoms.

The ester dispersants may be diesters of succinic acids or acid esters, i.e. partially esterified succinic acids, as well as partially esterified polyhydric alcohols or phenols, i.e. esters having free alcohol or phenol hydroxyl residues. Mixtures of the esters illustrated above are equally within the scope of this invention.

The ester dispersants can be prepared by any of many known processes, such as those illustrated in US-A-3,381,022 and US-A-3,836,471.

Hydroxyamines which can be reacted with the above long chain hydrocarbon substituted dicarboxylic acid materials to form dispersants include 2-amino-1-butanol, 2-amino-2-methyl-1-propanol, p-(β-hydroxyethyl)aniline, 2-amino-1-propanol, 3-amino-1-propanol, 2-amino-2-methyl-1,3-propanediol, 2-amino-2-ethyl-1,3-propanediol, N-(β-hydroxypropyl)-N'-(β-aminoethyl)piperazine, tris(hydroxymethyl)aminomethane (also known as trismethylolaminomethane), 2-amino-1-butanol, ethanolamine, β-(β-hydroxyethoxy)ethylamine, and the like. Mixtures of these or similar amines may also be used. The above description of nucleophilic reactants suitable for reaction with the hydrocarbyl-substituted dicarboxylic acid material includes amines, alcohols, and compounds having mixed amine and hydroxyl-containing reactive functional groups, i.e., amino alcohols.

A preferred group of ashless dispersants are those derived from polyisobutylene substituted with succinic anhydride groups and with the polyethylene amines, e.g. tetraethylene pentamine, pentaethylene hexamine, polyoxyethylene and polyoxypropylene amines, e.g. polyoxypropylene diamine, trismethylolaminomethane, or the alcohols described above such as pentaerythritol, and combinations thereof. One class of particularly preferred dispersants includes those derived from polyisobutylene substituted with succinic anhydride groups and reacted with (i) a hydroxy compound, e.g. pentaerythritol, (ii) a polyoxyalkylene polyamine, e.g. polyoxypropylene diamine, and/or (iii) a polyalkylene polyamine, e.g. polyethylene diamine and tetraethylene pentamine. Another class of particularly preferred dispersants includes those derived from polyisobutenyl succinic anhydride reacted with (i) a polyalkylene polyamine, e.g. tetraethylene pentamine, and/or (ii) a polyhydric alcohol or polyhydroxy substituted aliphatic primary amine, e.g. B. pentaerythritol or trismethylolaminomethane.

2. Reaction products of relatively high molecular weight aliphatic or alicyclic halides with amines, preferably polyalkylenepolyamines. These can be characterized as "amine dispersants" and examples of these are described, for example, in U.S. Patent Nos. 3,454,555 and 3,565,804.

3. Reaction products of alkylphenols in which the alkyl group contains at least about 30 carbon atoms with aldehydes (particularly formaldehyde) and amines (particularly polyalkylenepolyamines) which can be characterized as "Mannich dispersants". The materials described in the following American patents are exemplary:

US-A-3 725 277, US-A-3 725 480, US-A-3 726 882 and US-A-3 980 569.

4. Products obtained by post-treating the carboxyl, amine or Mannich dispersants with such reagents as urea, thiourea, carbon disulfide (carbon disulfide), phosphosulfurized hydrocarbons, aldehydes, ketones, carboxylic acids, hydrocarbon-substituted succinic anhydrides, nitriles, epoxides, boron compounds, phosphorus compounds or the like. Exemplary materials of this type are described in the following American patents: US-A-2 805 217, US-A-3 087 936, US-A-3 254 025, US-A-3 394 179, US-A-3 511 780, US-A-3 703 536, US-A-3 704 308, US-A-3 708 422, US-A-3 850 822, US-A-4 113 639 and US-A-4 116 876.

More specifically, the nitrogen and ester-containing dispersants are preferably further treated by boration, as generally taught in U.S. Patent Nos. 3,087,936 and 3,254,025 (incorporated herein by reference). This is conveniently accomplished by treating the selected nitrogen dispersant with a boron compound selected from the class consisting of boron oxide, boron halides, boric acids, and esters of boric acids in an amount to provide from about 0.1 atomic parts boron for each mole of nitrogen dispersant up to about 20 atomic parts boron for each atomic part nitrogen of the nitrogen dispersant. Useful borated dispersants contain from about 0.05 to 2.0 wt.%, e.g. B. 0.05 to 0.7 wt% boron based on the total weight of the borated nitrogen dispersant. It is believed that the boron, which appears to be present in the product as dehydrated boric acid polymers (primarily (HBO₂)₃), attaches to the dispersant imides and diimides as amine salts, e.g. the metaborate salt of this diimide.

The treatment is conveniently carried out by adding about 0.05 to 4, e.g. 1 to 3, weight percent (based on the weight of the nitrogen dispersant) of the boron compound, preferably boric acid, which is usually added to the nitrogen dispersant as a slurry, to the nitrogen dispersant and heating to about 135 to 190°C, e.g. 140 to 170°C, with stirring for 1 to 5 hours, followed by nitrogen stripping at these temperature ranges. The boron treatment can also be carried out by adding boric acid to the hot reaction mixture of the dicarboxylic acid material and amine while removing water.

5. Interpolymers of oil-solubilizing monomers such as decyl methacrylate, vinyl decyl ether and high molecular weight olefins and monomers containing polar substituents, e.g., aminoalkyl acrylates or acrylamides and poly(oxyethylene) substituted acrylates. These can be characterized as "polymer dispersants" and examples thereof are disclosed in the following patents: US-A-3,329,658, US-A-3,519,565, US-A-3,666,730 and US-A-3,702,300.

All of the above-mentioned patents are incorporated herein by reference for their disclosures of ashless dispersants.

Lubricating oil flow improvers (LOFI) cover all those additives that alter the size, number and growth of wax crystals in lubricating oils in such a way as to impart to the oils low temperature processability, pumpability and/or vehicle operability as measured by such tests as pour point and low rotation viscometry (MRV). The majority of lubricating oil flow improvers are polymers or contain polymers. These polymers generally consist of two types, either backbone or side chains.

The backbone variants, such as ethylene vinyl acetates (EVA), have different lengths of methylene segments randomly distributed in the backbone of the polymer, which associate with or co-crystallize with the paraffin crystals and thus prevent further crystal growth due to branching and non-crystallizable segments in the polymer.

The side chain type polymers, which are the variety predominantly used as LOFI's, have methylene segments as side chains, preferably as straight side chains. These polymers work in a similar manner to the backbone type, except that the side chains have been shown to be more effective in treating isoparaffins as well as n-paraffins found in lubricating oils. Representative examples of this polymer type include C8 to C18 dialkyl fumarate/vinyl acetate copolymers, polyacrylates, polymethacrylates and esterified styrene/maleic anhydride copolymers.

Foaming can be controlled by a polysiloxane type antifoam agent, such as silicone oil and polydimethylsiloxane.

Antiwear agents, as the name implies, reduce the wear of moving metal parts. Examples of conventional antiwear agents that can be used to assist the present phosphorus and sulfur containing reaction product mixture are the zinc dialkyldithiophosphates and the zinc diaryldithiophosphates. It is an important advantage of the present invention that adjunct antiwear agents need not be used and, in fact, can be excluded from the compositions of the invention.

Seal swellants include mineral oils of the type which cause swelling, including aliphatic alcohols having 8 to 13 carbon atoms such as tridecyl alcohol, with a preferred seal swellant being characterized as an oil-soluble, saturated, aliphatic or aromatic hydrocarbon ester having 10 to 60 carbon atoms and 2 to 4 bonds, e.g., dihexyl phthalate as described in U.S. Patent No. 3,974,081.

Some of these diverse additives can provide multiple effects, e.g., dispersant-oxidant. This approach is well known and does not need to be further elaborated here.

Compositions containing these conventional additives are typically blended with the base oil in amounts effective to effect their normal expected function. Representative effective amounts of such additives are illustrated as follows: Compositions Wt.% (general) Wt.% (preferred) Viscosity modifier Corrosion inhibitor Antioxidant Dispersant Lubricating oil flow improver Detergent/rust inhibitor Antifoam agent Antiwear agent Seal swelling agent Friction modifier Mineral oil base substance Difference up to 100%

In a broad sense, therefore, the hydroxyetheramine compounds of the present invention, when used in a lubricating oil composition, typically in a minor amount, are effective to impart increased frictional variance properties thereto as compared to the same composition in the absence of the hydroxyetheramine compounds. Additional conventional additives selected to meet the particular requirements of a chosen type of lubricating oil composition may also be included if desired.

Thus, while any effective amount of the hydroxyetheramine additives may be incorporated into the final formulated lubricating oil composition, such an effective amount is considered sufficient to provide a given composition with a hydroxylamine additive level of typically about 0.05 to about 5, preferably about 0.08 to about 1, and most preferably about 0.01 to about 0.5 weight percent, based on the weight of the composition. Similarly, while any effective amount of the organic phosphite esters described herein may be used in conjunction with the hydroxyetheramine additive, such an effective amount is considered sufficient to provide a given composition with a hydroxylamine additive level of typically about 0.05 to about 5, preferably about 0.08 to about 1, and most preferably about 0.01 to about 0.5 weight percent, based on the weight of the composition. which provides an oil composition with an amount of the phosphite ester additive of typically about 0.1 to about 1, preferably about 0.2 to about 0.8, and most preferably about 0.3 to about 0.6 weight percent, based on the weight of the composition.

It may be desirable, although not necessary, to prepare additive concentrates comprising concentrated solutions or dispersions of the hydroxyetheramine compounds or the phosphite esters and hydroxyetheramine compounds, together with other additives (the concentrate additive mixture is referred to herein as an additive package), whereby several additives can be added simultaneously to the base oil to form the lubricating oil compositions. Dissolution of the additive concentrate in the lubricating oil can be facilitated by solvents and by mixing with gentle heating, but this is not essential. The concentrate or additive package will typically be formulated to contain the hydroxyetheramine compound or the inventive combination of the phosphite ester and the hydroxyetheramine compound and optionally additional additives in appropriate amounts to provide the desired concentrations in the final formulation when the additive package is combined with a predetermined amount of base lubricant. Accordingly, the hydroxyetheramine compound or the phosphite ester and the hydroxyetheramine compound, together with other desirable additives, can be added to small amounts of base oil or other compatible solvents to form concentrates containing active ingredients in total amounts of typically from about 0.1 to about 50 weight percent, preferably from about 0.7 to about 25 weight percent, and most preferably from about 1.0 to about 10 weight percent of additives in appropriate proportions.

The finished formulations can typically use about 10 wt% of the additive package, with the remainder being base oil.

All weight percentages mentioned here refer to the active ingredient (ai) content of the additive and/or to the total weight of any additive package or formulation, which is the sum of the ai weights of each additive and the total weight of the oil or diluent.

As noted above, the organic phosphite esters contemplated for use in this invention are characterized by good compatibility with the hydroxyetheramine compounds. Accordingly, lubricating oil compositions containing both of these additives exhibit excellent friction stability. This has the additional advantage of allowing a reduction in the amount of hydroxyetheramine compound or other friction modifier required to obtain the total friction change desired. It has been found that the more the amount of hydroxyetheramine compound or other friction modifier in an ATF is increased, the lower the static slip torque becomes. As the static slip torque (as well as the static slip friction coefficient) decreases, the bands and clutches of the automatic transmission become increasingly susceptible to slippage. Therefore, it is extremely advantageous to be able to adjust, e.g. reduce, the amount of friction modifier (and thus any associated friction stability enhancer) without sacrificing the friction modifier properties of the fluid, as measured, e.g., by the torque difference TO-TD and its stability, as this facilitates the simultaneous achievement of both the desired static slip torque and the torque difference friction properties.

In short, the combination of organic phosphite ester and the hydroxyetheramine compound allows the chemical additive supplier to flexibly tailor an ATF to achieve the required balanced properties required under today's more stringent transmission manufacturer specifications.

The following examples are given as specific illustrations of the invention claimed. It is to be understood that the invention is not limited to the specific details described in the examples. All parts and percentages in the examples and in the remainder of the Description and claims refer to weight unless otherwise stated.

example 1

A hydroxyetheramine compound having the formula

where X is O, R1 is a C18 aliphatic hydrocarbon radical, R3 is hydrogen, R2 is C3 alkylene, R4 and R5 are both C2 alkylene radicals, and p and p' are each 1, was prepared by first reacting 270 parts by weight of octadecenyl alcohol with 53 parts by weight of acrylonitrile in the presence of an acidic or basic catalyst at a temperature in the range of 20 to 60°C for about 6 hours to form an ether nitrile intermediate. The intermediate was then hydrogenated in the presence of a Raney nickel catalyst at a temperature in the range of 140 to 150°C for about 2 hours to form an ether amine. The etheramine was then reacted with 44 parts by weight of ethylene oxide in the presence of a basic catalyst at a base temperature in the range of about 150°C for 6 hours to form the hydroxyetheramine product.

Example 2

An ATF base fluid, hereinafter referred to as test base, was formulated with conventional amounts of sealant, dispersant, antioxidant, viscosity index improver and mineral oil base.

To a sample of the test base, 0.5 wt.% triphenyl phosphite (TPP) and 0.2 wt.% of a thiobisethylene dodecyl succinate hemiester with the formula

The resulting formulation is referred to as Comparative Formulation 1C.

To another sample of the test base was added 0.2 wt% of zinc C4/C5 dialkyl dithiophosphate (ZDDP) and 0.2 wt% of the hydroxyetheramine friction modifier prepared according to Example 1. The resulting formulation is referred to as Comparative Formulation 2C.

To another sample of the test base was added 0.2 wt% ZDDP and 0.2 wt% of the same friction modifier used in Formulation 1C. The resulting formulation is referred to as Comparative Formulation 3C.

To another sample of the test base was added 0.5 wt% TPP and 0.2 wt% of the same hydroxyetheramine friction modifier used in Formulation 2C. The resulting formulation is referred to as Formulation 4.

To another sample of the test base was added 0.5 wt% dioleyl phosphite (DOP) and 0.2 wt% of the same hydroxyetheramine friction modifier used in Formulation 4. The resulting formulation is referred to as Comparative Formulation 5C.

The compositions of formulations 1C to 5C are summarized in Table 1 as follows. Table 1 Formulation No. Component, wt.% Dioleyl phosphite Triphenyl phosphite Hydroxyetheramine Succinate hemiester (Formula X) Zinc dialkyldithiophosphate Test base

The above formulations were then tested in accordance with a modified SAE No. 2 friction test and a Vickers antiwear test (Vickers AW test).

4 000 cycle friction test

This test used an SAE No. 2 friction machine which was successfully operated for 4,000 cycles without any unusual clutch disc wear or disc flaking on the side of the assembly. The test was conducted in a continuous series of 20 second cycles, each cycle consisting of three phases as follows: Phase I (10 seconds) - engine on to a speed of 3,600 rpm, clutch discs disengaged; Phase II (5 seconds) - engine off, clutch discs engaged; and Phase III (5 seconds) - engine off, clutch discs released. 4,000 cycles were repeated using 20,740 J of flywheel energy with 40 psi of clutch pressure applied. During clutch engagement, the friction torque in the region where engine speed decreased from 3,600 rpm to 0 was plotted as a function of time. From the torque curves, the dynamic torque (TD) halfway between the start and end of clutch engagement (ie at an engine speed of 1 800 rpm) and the torque (T�0) just before from standstill, e.g., between 20 and 0 rpm. The amount of time in seconds in Phase II that the engine speed took to go from 3,600 to 0 rpm is referred to as the standstill time. The torque ratio of the oil formulation is then determined from T₀/TD. In addition to determining the midpoint dynamic torque (TD) and static torque (T₀), the static slip torque (TS) was also determined. This was accomplished by rotating the composition disks at 2 to 3 rpm under a 40 psi load while the steel reaction disks were restrained and prevented from rotating. The torque was then measured until slipping occurred. The maximum torque observed was then recorded as TS. From TS, the static slip torque ratio (TS/TD) is calculated.

The static torque ratio expresses the ability of the transmission to resist slip; the lower the ratio, the greater the slip.

The test results for formulations 1C to 5C are shown in Table 2. The values given in Table 2 were measured after 200 and 4 000 operating cycles. Table 2 4,000 Cycle Friction Test Test Formulation Test Cycle 1 = acceptable range for TD = 120 to 150 2 = acceptable range for TS is 90 to 130. 3 = acceptable range for T₀/TD is 0.90 to 1.0. 4 = change in TS from 200 to 4,000 cycles. Maximum acceptable is 40. ΔTS represents friction resistance. 5 = acceptable range for TS/TD = 0.6 to 1.1.

As can be seen from Table 2, Formulation 1C results in a T0/TD value that is unacceptable at 200 cycles. The change in TS of 19 measured between 200 and 4,000 cycles for Formulation 1C and 24 for Formulation 3C are also much higher than that obtained for Formulation 4. Formulation 2C shows acceptable friction values but, as will be seen below in relation to the Vickers anti-wear values, shows poor wear properties. It is therefore evident that Formulations 1C, 2C and 3C represent less desirable formulations.

Formulation 4 results in acceptable values for all TD, TS and T₀/TD after 200 cycles. The T₀/TD value of 0.99 after 200 cycles is at the upper end of the acceptable range and would result in a satisfactory gear shift feel in a vehicle. Comparing the values after 200 cycles with those after 4,000 cycles gives an indication of friction retention. From this comparison it can be seen that for Formulation 4 TS changes by only 5 Nm. This change is much less than the allowable change for this test. The values show that Formulation 4 has excellent friction retention and meets all acceptable limits for the parameters as shown.

With reference to Formulation 5C, the data for TS after 4 000 cycles and for T₀/TD after 200 and 4 000 cycles show values below the acceptable limits.

The data in Table 2 thus demonstrate the superior friction properties of an ATF formulated with a hydroxylamine friction modifier and an antiwear additive in accordance with the invention over a similar ATF containing a conventional friction modifier and/or an antiwear agent outside the range of the invention.

Vickers anti-wear test

This vane pump wear test is fully described in ASTM Method D2882. It uses a constant volume, high pressure vane pump to indicate the wear characteristics of petroleum and non-petroleum hydraulic fluids. The procedure of the test performed here differs from ASTM D2882 only in the pump discharge pressure (1,000 psi versus 2,000 psi) and fluid temperature (175ºF). The test conditions are as follows: Pump outlet pressure Liquid temperature, Pump inlet Pump speed Liquid feed gal Liter

The Vickers 104C vane pump cassette is used for the study. At the end of 24 hours of the test period and again at the end of 100 hours of the test period, the cam ring and vanes are measured for their total weight loss. The maximum allowable weight loss in this test is 15 mg. The test results for formulations 1C to 5C are shown in Table 3. Table 3 Vickers anti-wear test formulations Vickers weight loss on ring and vane, mg. hours

Referring to Table 3, it is evident that the results for Formulation 4, which contains both the hydroxyetheramine friction modifier and triphenyl phosphite, are superior to those for all other formulations after 24 hours, including those for Formulations 2C and 5C, which contain the same hydroxyetheramine friction modifier but either ZDDP (Formulation 2C) or dioleyl phosphite (Formulation 5C) instead of triphenyl phosphite. Only Formulation 5C shows better wear after 100 hours, but as shown in Table 2, this formulation has poor friction performance. The formulations in which the hydroxyetheramine friction modifier was replaced with the succinate hemiester friction modifier showed poor test results, regardless of whether the formulations included triphenyl phosphite (Formulation 1C) or ZDDP (Formulation 3C).

The data in Tables 2 and 3 together demonstrate the advantage of using triphenyl phosphite (TPP) in combination with the hydroxyetheramine over ZDDP or dioleyl phosphite as an antiwear additive.

Claims (14)

1. Power transmission fluid, which (a) a natural or synthetic base oil; (b) a friction-modifying amount of a borated or non-borated hydroxyetheramine compound having the formula in which X is O or S, R1 is a straight-chain or branched-chain, saturated or unsaturated, aliphatic C3 to C27 hydrocarbon radical, R2 is a straight-chain or branched-chain C1 to C6 alkylene radical, R3 is H or CH3, R4 and R5 are independently straight-chain or branched-chain C2 to C5 alkylene radicals, and p and p' are independently 1 to 4, the hydroxyetheramine compound having a total of 10 to 30 carbon atoms; (c) an amount effective to impart anti-blocking properties to the fluid of an organic phosphite ester having the formula in which R₆ is a hydrocarbon radical selected from the group consisting of aryl and C₁ to C₃-alkaryl and R₇ and R₄ independently are a hydrocarbon radical selected from the group consisting of aryl, C₁ to C₂₅-alkyl, C₁ to C₃-alkaryl, C₅ to C₈-cycloalkyl and halogen-substituted derivatives thereof, and (d) at least one additional compound in an amount effective to impart to the fluid at least one of antioxidation, seal swelling, dispersibility and viscosity change properties, includes. 2. A power transmission fluid according to claim 1, wherein X is O and R₂, R₄ and R2 are straight chain alkylene radicals. 3. A power transmission fluid according to claim 1 or claim 2, wherein R₁ is a C₁₆ to C₂₀ alkylene radical and R₂ is a C₂ to C₄ alkylene radical. 4. A power transmission fluid according to any one of claims 1 to 3, wherein R₁ is C₁₈ alkylene, R₂ is C2 alkylene, R₃ is H and R₄ and R₅ are C₂ alkylene. 5. A power transmission fluid according to any one of claims 1 to 4, wherein R6, R7 and R8 are selected from the group consisting of alkyl, aryl and alkaryl radicals. 6. A power transmission fluid according to any one of claims 1 to 5, wherein the phosphite ester is triphenyl phosphite. 7. A power transmission fluid according to any one of claims 1 to 6, wherein the organic phosphite is present in an amount of 0.1 to 1% by weight based on the weight of the fluid. 8. A power transmission fluid according to any one of claims 1 to 7, wherein the base oil is a mineral oil and the fluid is an automatic transmission fluid. 9. Use to modify the frictional properties of a natural or synthetic base oil which is usable as a power transmission fluid, of (i) a borated or non-borated hydroxyetheramine compound having the formula in which X is O or S, R₁ is a straight-chain or branched-chain, saturated or unsaturated, aliphatic C₃ to C₂₇-hydrocarbon radical, R₂ is a straight-chain or branched-chain C₁ to C₆-alkylene radical, R₃ is H or CH₃, R₄ and R₅ are independently straight-chain or branched-chain C₂ to C₅-alkylene radicals and p and p' are independently 1 to 4, wherein the hydroxyetheramine compound has a total of 10 to 30 carbon atoms, together with (ii) an organic phosphite ester having the formula in which R₆ is a hydrocarbon radical selected from the group consisting of aryl and C₁ to C₃ alkaryl and R₇ and R₈ independently are a hydrocarbon radical selected from the group consisting of aryl, C₁ to C₂₅ alkyl, C₁ to C₃ alkaryl, C₅ to C₈ cycloalkyl and halogen-substituted derivatives thereof, together with (iii) at least one additional compound in an amount effective to provide the liquid with at least one of the properties of antioxidant effect, seal swelling, dispersibility and viscosity change. 10. Use according to claim 9, wherein the phosphite ester is triphenyl phosphite. 11. Use according to claim 9 or claim 10, wherein the base oil is a mineral oil and the power transmission fluid is an automatic transmission fluid. 12. Additive concentrate for incorporation into a natural or synthetic base oil to produce a power transmission fluid, the additive concentrate (i) an oil solution of a borated or non-borated hydroxyetheramine compound having the formula in which X is O or S, R₁ is a straight-chain or branched-chain, saturated or unsaturated, aliphatic C₃ to C₂₇-hydrocarbon radical, R₂ is a straight-chain or branched-chain C₁ to C₆-alkylene radical, R₃ is H or CH₃, R₄ and R₅ are independently straight-chain or branched-chain C₂ to C₅-alkylene radicals and p and p' are independently 1 to 4, wherein the hydroxyetheramine compound has a total of 10 to 30 carbon atoms; (ii) an organic phosphite ester having the formula in which R₆ is a hydrocarbon radical selected from the group consisting of aryl and C₁ to C₃-alkaryl and R₇ and R₈ independently represent a hydrocarbon radical selected from the group consisting of aryl, C₁ to C₂₅-alkyl, C₁ to C₃-alkaryl, C₅ to C₈-cycloalkyl and halogen-substituted derivatives thereof, and (iii) at least one additional compound to impart to the liquid at least one of the properties of anti-oxidation, seal swelling, dispersibility and viscosity change, includes. 13. A concentrate according to claim 12, wherein the phosphite ester is triphenyl phosphite. 14. A concentrate according to claim 12 or claim 13, wherein the base oil is a mineral oil and the transmission fluid is an automatic transmission fluid.