WO2015056062A1 - Procédé d'utilisation de coefficients de frottement élevés sur des embrayages à friction lubrifiés à l'huile - Google Patents

Procédé d'utilisation de coefficients de frottement élevés sur des embrayages à friction lubrifiés à l'huile Download PDF

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Publication number
WO2015056062A1
WO2015056062A1 PCT/IB2014/001586 IB2014001586W WO2015056062A1 WO 2015056062 A1 WO2015056062 A1 WO 2015056062A1 IB 2014001586 W IB2014001586 W IB 2014001586W WO 2015056062 A1 WO2015056062 A1 WO 2015056062A1
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Prior art keywords
monomer
friction
carbon atoms
statistical copolymer
formula
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PCT/IB2014/001586
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English (en)
Inventor
Raymond F. Watts
Joseph R. NOLES, Jr.
Michael Muller
Torsten Stöhr
Boris Eisenberg
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Infineum International Limited
Evonik Oil Additives Gmbh
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Publication of WO2015056062A1 publication Critical patent/WO2015056062A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M149/00—Lubricating compositions characterised by the additive being a macromolecular compound containing nitrogen
    • C10M149/02—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • C10M149/10—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing monomers having an unsaturated radical bound to a nitrogen-containing hetero ring
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M145/00—Lubricating compositions characterised by the additive being a macromolecular compound containing oxygen
    • C10M145/02—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • C10M145/10—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing monomers having an unsaturated radical bound to a carboxyl radical, e.g. acrylate
    • C10M145/12—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing monomers having an unsaturated radical bound to a carboxyl radical, e.g. acrylate monocarboxylic
    • C10M145/14—Acrylate; Methacrylate
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M145/00—Lubricating compositions characterised by the additive being a macromolecular compound containing oxygen
    • C10M145/02—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • C10M145/10—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing monomers having an unsaturated radical bound to a carboxyl radical, e.g. acrylate
    • C10M145/16—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing monomers having an unsaturated radical bound to a carboxyl radical, e.g. acrylate polycarboxylic
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M159/00—Lubricating compositions characterised by the additive being of unknown or incompletely defined constitution
    • C10M159/005—Macromolecular compounds, e.g. macromolecular compounds composed of alternatively specified monomers not covered by the same main group
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M2209/00—Organic macromolecular compounds containing oxygen as ingredients in lubricant compositions
    • C10M2209/02—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • C10M2209/08—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing monomers having an unsaturated radical bound to a carboxyl radical, e.g. acrylate type
    • C10M2209/084—Acrylate; Methacrylate
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M2209/00—Organic macromolecular compounds containing oxygen as ingredients in lubricant compositions
    • C10M2209/02—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • C10M2209/08—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing monomers having an unsaturated radical bound to a carboxyl radical, e.g. acrylate type
    • C10M2209/086—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing monomers having an unsaturated radical bound to a carboxyl radical, e.g. acrylate type polycarboxylic, e.g. maleic acid
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M2215/00—Organic non-macromolecular compounds containing nitrogen as ingredients in lubricant compositions
    • C10M2215/28—Amides; Imides
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M2217/00—Organic macromolecular compounds containing nitrogen as ingredients in lubricant compositions
    • C10M2217/02—Macromolecular compounds obtained from nitrogen containing monomers by reactions only involving carbon-to-carbon unsaturated bonds
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M2217/00—Organic macromolecular compounds containing nitrogen as ingredients in lubricant compositions
    • C10M2217/02—Macromolecular compounds obtained from nitrogen containing monomers by reactions only involving carbon-to-carbon unsaturated bonds
    • C10M2217/028—Macromolecular compounds obtained from nitrogen containing monomers by reactions only involving carbon-to-carbon unsaturated bonds containing monomers having an unsaturated radical bound to a nitrogen-containing hetero ring
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
    • C10M2221/00—Organic macromolecular compounds containing sulfur, selenium or tellurium as ingredients in lubricant compositions
    • C10M2221/02—Macromolecular compounds obtained by reactions of monomers involving only carbon-to-carbon unsaturated bonds
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
    • C10N2020/00—Specified physical or chemical properties or characteristics, i.e. function, of component of lubricating compositions
    • C10N2020/01—Physico-chemical properties
    • C10N2020/04—Molecular weight; Molecular weight distribution
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
    • C10N2030/00—Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
    • C10N2030/06—Oiliness; Film-strength; Anti-wear; Resistance to extreme pressure
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
    • C10N2040/00—Specified use or application for which the lubricating composition is intended
    • C10N2040/04—Oil-bath; Gear-boxes; Automatic transmissions; Traction drives
    • C10N2040/042—Oil-bath; Gear-boxes; Automatic transmissions; Traction drives for automatic transmissions
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
    • C10N2040/00—Specified use or application for which the lubricating composition is intended
    • C10N2040/04—Oil-bath; Gear-boxes; Automatic transmissions; Traction drives
    • C10N2040/044—Oil-bath; Gear-boxes; Automatic transmissions; Traction drives for manual transmissions
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
    • C10N2040/00—Specified use or application for which the lubricating composition is intended
    • C10N2040/04—Oil-bath; Gear-boxes; Automatic transmissions; Traction drives
    • C10N2040/045—Oil-bath; Gear-boxes; Automatic transmissions; Traction drives for continuous variable transmission [CVT]

Definitions

  • This invention relates to a method of increasing the dynamic coefficient of friction in an oil-lubricated friction clutch, so providing a friction clutch - lubricant system capable of providing high levels of torque transfer in applications such as vehicular automatic transmissions. More particularly, the present invention is directed to a method of increasing the friction in an oil-lubricated friction clutch using a lubricating oil containing at least one copolymer as hereinafter defined, the presence of which develops higher dynamic friction levels in oil- lubricated clutches than otherwise comparable lubricants formulated without the specified copolymer.
  • Increasing the friction level in the clutch has the desirable effect of increasing the level of torque that can be transferred through the clutch which, in turn, requires less surface area to transmit the same amount of torque. Therefore, in an oil-lubricated clutch having, for example, five fiber plates, a 20% increase in dynamic friction provided by the lubricant would allow for the removal of one paper plate and one steel plate, thereby providing a corresponding 20% decrease in the weight and size of the clutch.
  • Such hardware reductions assist a vehicle manufacturer to design lighter vehicles with attendant fuel efficiency benefits, as well as reducing the complexity of component design, with attendant cost and reliability benefits.
  • lubricating oils particularly lubricating power transmitting oils, more particularly automatic transmission oils, incorporating certain copolymers as hereinafter defined
  • oil- lubricated friction clutches having composite (i.e. cellulose-based) friction linings deliver increased levels of dynamic friction that enable the transmissions in which they are used to be made smaller, decreasing the size and weight of the transmission and resulting in an improvement in fuel efficiency and hardware design
  • Applicants have discovered that the polymers described hereinunder are particularly effective in cooperation with ashless dispersants to increase the dynamic coefficient of friction of a lubricant for oil-lubricated friction clutches.
  • Copolymers of (meth)acrylic esters be they non-functionalised or even functionalised by introducing amine functionalities via N,N-dimethylaminopropyl methacrylamide DMAPMAAm are known in the industry; see for example R.M. Mortier, S.T. Orszulik (eds.), Chemistry and Technology of Lubricants, Blackie Academic & Professional, London 1993.
  • EP-A-0 339 088 and US-A-3 925 217 describe the use of polymers or compounds with cyclic substituents as means to achieve high friction coefficients. They do not contemplate the polymers hereinafter described.
  • the present invention is a method of increasing the friction in an oil-lubricated friction clutch having a cellulose-based friction lining, or in a power- transmission device utilising said clutch, the method comprising:
  • a lubricant composition comprising (i.a) a major amount of oil of lubricating viscosity, and
  • step (ii) lubricating said clutch or device with the lubricant composition resulting from step (i);
  • At least one copolymer (i.b) is a statistical copolymer derived essentially from the following monomers (a) and (b):
  • R is hydrogen or methyl
  • R 1 is a linear or branched chain alkyl group having from 6 to 36 carbon atoms
  • R 2 and R 3 are each independently hydrogen or a group of the formula -COOR' in which R is hydrogen or a linear or branched chain alkyl group having from 6 to 36 carbon atoms;
  • R is hydrogen or methyl
  • X is oxygen, sulfur or an amino group of the formula -NH- or -NR a - in which R a is an alkyl radical having from 1 to 40 carbon atoms
  • R 4 is a radical comprising from 2 to 100 carbon atoms and contains at least 2 oxygen, sulfur or nitrogen atoms
  • R 5 and R 6 are each independently hydrogen or a group of the formula -COX'R 7 in which X' is oxygen or an amino group of the formula -NH- or -NR a - in which R a is an alkyl radical having from 1 to 40 carbon atoms, and R 7 is a radical comprising from 1 to 100 carbon atoms;
  • monomer units originating from monomer (b) constitute from 0.1 to 30 weight percent of the total weight of said statistical copolymer.
  • the statistical copolymers defined in the above method increase the dynamic coefficients of friction of lubricant compositions for oil-lubricated friction clutches.
  • the polymer architecture resulting from the statistical monomer distribution in combination with the nature and relative proportion of units derived from the monomer (b), provides excellent dynamic friction-increasing properties for lubricating oils.
  • the dynamic coefficient of friction is especially increased where the level of monomer (b) is below 10 weight percent of the total weight of such statistical copolymer, more preferably in the range of 1 to 6 weight percent; and more preferably where the weight-average molecular weight, Mw, as measured by GPC, is also within the range of 10,000 to 60,000, and most preferably within the range of 40,000 to 60,000 g/mol, as determined, for example, in tetrahydrofuran at 35°C against a polymethyl methacrylate calibration curve composed of a set of at least 25 standards (obtainable from the Polymer Standards Service or Polymer Laboratories, Mainz, Germany) whose M pea k is distributed in logarithmically uniform manner over the range from 5.10 6 to 2.10 2 g/mol.
  • Mw weight-average molecular weight
  • the lubricant composition resulting from step (i) additionally comprises (i.c) an ashless dispersant, wherein said dispersant is present in an amount that is effective in combination with the copolymer (i.b) to increase the dynamic coefficient of friction of the lubricant composition when used in said clutch or device.
  • the level of dynamic friction of the lubricant is especially increased where the level of monomer (b) is below 10 weight percent of the total weight of said statistical copolymer, more preferably in the range of 6 to 10 weight percent; and more preferably where the weight-average molecular weight, Mw, as measured by GPC, is also within the range of 10,000 to 60,000, and most preferably within the range of 10,000 to 40,000 g/mol as measured against the above-referenced standards.
  • the invention is the use of one or more statistical copolymers derived essentially from the following monomers (a) and (b) :
  • R is hydrogen or methyl
  • R 1 is a linear or branched chain alkyl group having from 6 to 36 carbon atoms
  • R 2 and R 3 are each independently hydrogen or a group of the formula -COOR in which R is hydrogen or a linear or branched chain alkyl group having from 6 to 36 carbon atoms; and (b) at least one ethylenically unsaturated ester compound of the formula (II)
  • R is hydrogen or methyl
  • X is oxygen, sulfur or an amino group of the formula -NH- or -NR a - in which R a is an alkyl radical having from 1 to 40 carbon atoms
  • R 4 is a radical comprising from 2 to 100 carbon atoms and contains at least 2 oxygen, sulfur or nitrogen atoms
  • R 5 and R 6 are each independently hydrogen or a group of the formula -COX'R 7 in which X' is oxygen or an amino group of the formula -NH- or -NR a - in which R a is an alkyl radical having from 1 to 40 carbon atoms, and R 7 is a radical comprising from 1 to 100 carbon atoms;
  • monomer units originating from monomer (b) constitute from 0.1 to 30 weight percent of the total weight of said statistical copolymer
  • a lubricant composition comprising a major amount of oil of lubricating viscosity, to increase the dynamic coefficient of friction exhibited by the lubricant composition in an oil-lubricated friction clutch having a cellulose-based friction lining or in a power-transmission device utilising said clutch.
  • the invention is the use of an ashless dispersant in cooperation with one or more statistical copolymers derived essentially from the following monomers (a) and (b):
  • R is hydrogen or methyl
  • R 1 is a linear or branched chain alkyl group having from 6 to 36 carbon atoms
  • R 2 and R 3 are each independently hydrogen or a group of the formula -COOR in which R is hydrogen or a linear or branched chain alkyl group having from 6 to 36 carbon atoms; and (b) at least one ethylenically unsaturated ester compound of the formula (IV)
  • R is hydrogen or methyl
  • X is oxygen, sulfur or an amino group of the formula -NH- or -NR a - in which R a is an alkyl radical having from 1 to 40 carbon atoms
  • R 4 is a radical comprising from 2 to 100 carbon atoms and contains at least 2 oxygen, sulfur or nitrogen atoms
  • R 5 and R 6 are each independently hydrogen or a group of the formula -COX'R 7 in which X' is oxygen or an amino group of the formula -NH- or -NR a - in which R a is an alkyl radical having from 1 to 40 carbon atoms, and R 7 is a radical comprising from 1 to 100 carbon atoms;
  • monomer units originating from monomer (b) constitute from 0.1 to 30 weight percent of the total weight of said statistical copolymer
  • a lubricant composition comprising a major amount of oil of lubricating viscosity, to increase the dynamic coefficient of friction exhibited by the lubricant composition in an oil-lubricated friction clutch having a cellulose-based friction lining or in a power-transmission device utilising said clutch.
  • the combined presence of dispersant and the defined statistical copolymer(s) surprisingly brings about an increase in dynamic coefficient of friction in the clutch or device, particularly at higher operational speeds, that is greater than the increase observed for the corresponding copolymer(s) alone.
  • the invention is the use of one or more statistical copolymers (as defined under the above method or use aspects of the invention) in combination with one or more additive performance packages, to increase the dynamic coefficient of friction exhibited by the lubricant composition in an oil- lubricated friction clutch having a cellulose-based friction lining or in a power- transmission device utilising said clutch.
  • Figs 1 and 2 show graphically the relationship between friction coefficient and sliding speed achieved using the lubricating oil compositions of Performance Example 2.
  • Figs 3 and 4 show graphically the relationship between friction coefficient and sliding speed achieved using the lubricating oil compositions of Performance Example 3.
  • Oils of lubricating viscosity useful in the practice of the present invention are natural lubricating oils, synthetic lubricating oils and mixtures thereof. Suitable lubricating oils also include base stocks obtained by isomerization of synthetic wax and slack wax, as well as base stocks produced by hydrocracking (rather than by solvent treatment) the aromatic and polar components of a crude oil. In general, suitable lubricating oils will have a kinematic viscosity ranging from about 1 to about 40 mm 2 /s (cSt) at 100°C.
  • Typical applications will require the lubricating oil base stocks or base stock mixture to have a viscosity preferably ranging from about 1 to about 40 mm 2 /s (cSt), more preferably, from about 2 to about 8 mm 2 /s (cSt), most preferably, from about 2 to about 6 mm 2 /s (cSt), at 100°C.
  • Natural lubricating oils include animal oils, vegetable oils (e.g., castor oil and lard oil), petroleum oils, mineral oils, and oils derived from coal or shale.
  • the preferred natural lubricating oil is mineral oil.
  • the mineral oils useful in the practice of the invention include all common mineral oil base stocks. This would include oils that are naphthenic or paraffinic in chemical structure as well as oils that are refined by conventional methodology using acid, alkali, and clay or other agents such as aluminum chloride, as well as extracted oils produced, e.g., by solvent extraction or treatment with solvents such as phenol, sulfur dioxide, furfural, dichlorodiethyl ether, etc. They may be hydro treated or hydro refined, dewaxed by chilling or catalytic dewaxing processes, or hydro cracked.
  • the mineral oil may be produced from natural crude sources or be composed of isomerized wax materials or residues of other refining processes.
  • a particularly useful class of mineral oils includes those mineral oils that are severely hydro treated or hydro cracked. These processes expose the mineral oils to very high hydrogen pressures at elevated temperatures in the presence of
  • Typical processing conditions include hydrogen pressures of approximately 3000 pounds per square inch (psi) at temperatures ranging from 300°C to 450°C, over a hydrogenation-type catalyst.
  • This processing removes sulfur and nitrogen from the lubricating oil and saturates any alkylene or aromatic structures in the feedstock. The result is a base oil with extremely good oxidation resistance and viscosity index.
  • a secondary benefit of these processes is that low molecular weight constituents of the feed stock, such as waxes, can be isomerized from linear to branched structures thereby providing finished base oils with significantly improved low temperature properties. These hydro treated base oils may then be further dewaxed either catalytically or by conventional means to give them exceptional low temperature fluidity.
  • lubricating base oils made by one or more of the aforementioned processes are Chevron RLOP, Petro-Canada P65, Petro- Canada P 100, Yukong, Ltd., Yubase 4, Imperial Oil Canada MXT, and Shell XHVI 5.2. These materials are commonly referred to as API Group III mineral oils.
  • Such mineral oils will have kinematic viscosities of from about 1.0 mm 2 /s (cSt) to about 40.0 mm 2 /s (cSt) at 100°C.
  • Preferred mineral oils have kinematic viscosities of from about 2 to about 8 mm 2 /s (cSt), and most preferred are those mineral oils with kinematic viscosities of from about 2 to about 6 mm 2 /s (cSt), at 100°C.
  • Synthetic lubricating oils useful in the practice of the invention include hydrocarbon oils and halo-substituted hydrocarbon oils such as oligomerized, polymerized, and interpolymerized olefins (e.g., polybutylenes, polypropylenes, propylene, isobutylene copolymers, chlorinated polylactenes, poly(l-hexenes), poly(l-octenes), poly(l-decenes), etc., and mixtures thereof); alkylbenzenes (e.g., dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes, di(2-ethylhexyl)benzene, etc.); polyphenyls (e.g., biphenyls, terphenyls, alkylated polyphenyls, etc.]; and alkylated diphenyl ethers, alkylated diphenyl s
  • Synthetic lubricating oils also include alkylene oxide polymers, interpolymers, copolymers, and derivatives thereof where the terminal hydroxyl groups have been modified by esterification, etherification, etc.
  • This class of synthetic oils is exemplified by: polyoxyalkylene polymers prepared by polymerization of ethylene oxide or propylene oxide; the alkyl and aryl ethers of these polyoxyalkylene polymers (e.g., methyl-polyisopropylene glycol ether having an average molecular weight of 1000, diphenyl ether of polypropylene glycol having a molecular weight of 1000 - 1500); and mono- and poly-carboxylic esters thereof (e.g., the acetic acid esters, mixed C3-C8 fatty acid esters, and C 12 oxo acid diester of tetraethylene glycol).
  • Another suitable class of synthetic lubricating oils comprises the esters of dicarboxylic acids (e.g., phthalic acid, succinic acid, alkyl succinic acids and alkenyl succinic acids, maleic acid, azelaic acid, suberic acid, sebasic acid, fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkylmalonic acids, alkenyl malonic acids, etc.) with a variety of alcohols (e.g., butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoethers, propylene glycol, etc.).
  • dicarboxylic acids e.g., phthalic acid, succinic acid, alkyl succinic acids and alkenyl succinic acids, maleic acid, azelaic acid, suberic acid, sebasic acid, fumaric acid, adipic
  • esters include dibutyl adipate, di(2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl sebacate, the 2- ethylhexyl diester of linoleic acid dimer, and the complex ester formed by reacting one mole of sebasic acid with two moles of tetraethylene glycol and two moles of 2- ethylhexanoic acid, and the like.
  • Preferred types of synthetic oils include adipates of C 4 to C alcohols.
  • Esters useful as synthetic lubricating oils also include those made from C5 to C12 monocarboxylic acids and polyols and polyol ethers such as neopentyl glycol, trimethylolpropane pentaerythritol, dipentaerythritol, tripentaerythritol, and the like.
  • Silicon-based oils (such as the polyalkyl-, polyaryl-, polyalkoxy-, or polyaryloxy-siloxane oils and silicate oils) comprise another useful class of synthetic lubricating oils. These oils include tetraethyl silicate, tetraisopropyl silicate, tetra(2- ethylhexyl) silicate, tetra(4-methyl-2-ethylhexyl) silicate, tetra(p-tert-butylphenyl) silicate, hexa(4-methyl-2-pentoxy)disiloxane, poly(methyl) siloxanes and
  • poly(methylphenyl) siloxanes and the like.
  • Other synthetic lubricating oils include liquid esters of phosphorus-containing acids (e.g., tricresyl phosphate, trioctyl phosphate, and diethyl ester of decylphosphonic acid), polymeric tetra-hydrofurans, poly-a-olefins, and the like.
  • the lubricating oils may be derived from refined oils, re-refined oils, or mixtures thereof.
  • Unrefined oils are obtained directly from a natural source or synthetic source (e.g., coal, shale, or tar sands bitumen) without further purification or treatment.
  • Examples of unrefined oils include a shale oil obtained directly from a retorting operation, petroleum oil obtained directly from distillation, or an ester oil obtained directly from an esterification process, each of which is then used without further treatment.
  • Refined oils are similar to the unrefined oils except that refined oils have been treated in one or more purification steps to improve one or more properties.
  • Suitable purification techniques include distillation, hydrotreating, dewaxing, solvent extraction, acid or base extraction, filtration, and percolation, all of which are known to those skilled in the art.
  • Re-refined oils are obtained by treating used oils in processes similar to those used to obtain the refined oils. These re-refined oils are also known as reclaimed or reprocessed oils and are often additionally processed for removal of spent additives and oil breakdown products.
  • the lubricating oil used in this invention will be a natural lubricating oil. If a synthetic lubricating oil basestock is used, it is preferably a poly-a-olefin, monoester, diester, polyolester, or mixtures thereof. The preferred synthetic lubricating oil is a poly-a-olefin.
  • Component i.b. is at least one statistical copolymer derived essentially from the following monomers (a) and (b) :
  • R is hydrogen or methyl
  • R 1 is a linear or branched chain alkyl group having from 6 to 36 carbon atoms, preferably from 6 to 24 carbon atoms and more preferably from 6 to 15 carbon atoms
  • R 2 and R 3 are each independently hydrogen or a group of the formula -COOR' in which R is hydrogen or a linear or branched chain alkyl group having from 6 to 36 carbon atoms, preferably from 6 to 24 carbon atoms and more preferably from 6 to 15 carbon atoms; and
  • R is hydrogen or methyl
  • X is oxygen, sulfur or an amino group of the formula -NH- or -NR a - in which R a is an alkyl radical having from 1 to 40 carbon atoms, R 4 is a radical comprising from 2 to 100 and preferably 2 to
  • R 5 and R 6 are each independently hydrogen or a group of the formula -COX'R 7 in which X' is oxygen or an amino group of the formula -NH- or -NR a - in which R a is an alkyl radical having from 1 to 40 carbon atoms, and R 7 is a radical comprising from 1 to 100 carbon atoms; wherein the monomer units originating from monomer (b) constitute from 0.1 to 30 weight percent of the total weight of said statistical copolymer.
  • the term of art "statistical" is used to denote a copolymer that is derived from direct copolymerization of a mixture of two (or more) co- monomers under reaction conditions where the next co-monomer to insert into a growing polymer chain follows from the statistical distribution of co-monomers in the monomer mixture.
  • the co-monomer units are interspersed throughout the backbone, rather than present in discrete homopolymeric blocks.
  • the order of addition of the co-monomers into growing copolymer chains is determined in particular by the relative reactivities of the co-monomers, and the relative proportions of the co-monomers in the monomer mixture.
  • a statistical copolymer wherein the probability of finding a particular type of co-monomer unit at any particular point in the polymer chain is independent of the type(s) of surrounding co-monomer (i.e. where co-monomer reactivities are equivalent) can be referred to as a truly "random" copolymer .
  • Such copolymers fall within the meaning of "statistical” as used herein, and represent the outcome of polymer chain growth that is controlled solely by the distribution of co-monomers in the monomer mixture.
  • Applicants have found that the combination of the defined co-monomers and a statistical copolymer architecture with a relatively low content of monomer units derived from co-monomer (b), results in a copolymer which, when added to a lubricating oil, functions to increase the dynamic coefficient of friction of the oil when used to lubricate friction clutches or devices utilizing them.
  • the use of such copolymers as additives for such oils thereby enables the reductions in hardware and attendant benefits described above.
  • the inclusion in the copolymer chains of units derived from additional co-monomers conveys on the copolymer further advantageous performance, leading to copolymers that are multifunctional in their additive performance.
  • the statistical copolymer defined under all aspects of the invention is essentially derived from a mixture of co-monomers (a), (b) and one or more additional monomers of the type (c) as hereinafter described.
  • the additional interspersion of co-monomer (c) into the backbone causes the resulting copolymer to function both to increase dynamic friction in the above described oil-lubricated friction clutches (or power-transmission devices containing them) and to favourably modify the temperature-dependent viscosity characteristics of the lubricant composition, providing a combination of advantages to the lubricant.
  • Monomer (a) is one or more ethylenically unsaturated ester compounds of the formula
  • R is hydrogen or methyl
  • R 1 is a linear or branched alkyl radical having from 6 to 36 carbon atoms and preferably from 6 to 24 carbon atoms, more preferably 6 to 15 carbon atoms
  • R 2 and R 3 are each independently hydrogen or a group of the formula -COO in which R is hydrogen or an alkyl group having from 6 to 36 atoms and preferably from 6 to 24 carbon atoms, more preferably 6 to 15 carbon atoms.
  • Preferred embodiments of monomer (a) are acrylates, methacrylates and mixtures thereof (hereinafter collectively termed "(meth)acrylates”), fumarates and maleates, all of which are derived from alcohols of the formula R ⁇ OH. More preferably monomer (a) is one or more acrylates or methacrylates, or mixtures thereof derived from alcohols of the formula R ⁇ H.
  • Monomer (a) may be one or more (meth)acrylates which derive from unsaturated alcohols, for example oleyl (meth)acrylate; cycloalkyl (meth)acrylates such as 3-vinylcyclohexyl (meth)acrylate, cyclohexyl (meth)acrylate, bornyl
  • monomer (a) is one or more compounds selected from the group consisting of hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, heptyl (meth)acrylate, 2-tert-butylheptyl (meth)acrylate, octyl (meth)acrylate,
  • monomer (a) is an acrylate or methacrylate (or mixture thereof) wherein, in formula (I), R 1 is a linear or branched alkyl radical having from 12 to 15 carbon atoms, R is methyl and R 2 and R 3 are each preferably hydrogen.
  • Monomer (b) is at least one ethylenically unsaturated ester compound of the formula:
  • R is hydrogen or methyl
  • X is oxygen, sulfur or an amino group of the formula -NH- or -NR a - in which R a is an alkyl radical having from 1 to 40 carbon atoms
  • R 4 is a radical comprising from 2 to 100 carbon atoms, preferably 2 to 20 carbon atoms, and contains at least 2 oxygen, sulfur or nitrogen atoms
  • R 5 and R 6 are each independently hydrogen or a group of the formula -COX'R 7 in which X' is oxygen or an amino group of the formula -NH- or -NR a - in which R a is an alkyl radical having from 1 to 40 carbon atoms
  • R 7 is a radical comprising from 1 to 100 carbon atoms.
  • X is oxygen, sulfur or an amino group of the formula -NH- or -NR a - in which R a is an alkyl radical having from 1 to 40, preferably from 1 to 4 carbon atoms.
  • the R 4 radical in the monomer units originating from at least one monomer (b) comprises at least one nitrogen atom and at least one oxygen atom.
  • the R 4 radical in the monomer units originating from at least one monomer (b) comprises at least one urea group.
  • R 5 and R 6 radicals in formula (II) are each independently hydrogen or a group of the formula -COX'R 7 in which X' is oxygen, sulfur or an amino group of the formula -NH- or -NR a - in which R a is an alkyl radical having from 1 to 40 carbon atoms, preferably from 1 to 4 carbon atoms, and R 7 is a radical comprising from 1 to 100, preferably from 1 to 30 and more preferably from 1 to 15 carbon atoms.
  • R radical comprising from 1 to 100 carbon atoms indicates radicals of organic compounds having from 1 to 100 carbon atoms.
  • aromatic and heteroaromatic groups and also alkyl, cycloalkyl, alkoxy, cycloalkoxy, alkenyl, alkanoyl, alkoxycarbonyl groups and heteroaliphatic groups.
  • the groups mentioned may be branched or unbranched.
  • the R 4 radical is a radical comprising from 2 to 100, preferably from 2 to 20 carbon atoms.
  • the expression "radical comprising from 2 to 100 carbon atoms” indicates radicals of organic compounds having from 2 to 100 carbon atoms. It includes aromatic and heteroaromatic groups, and alkyl, cycloalkyl, alkoxy, cycloalkoxy, alkenyl, alkanoyl, alkoxycarbonyl groups, and also heteroaliphatic groups.
  • the groups mentioned may be branched or unbranched. In addition, these groups may have customary substituents.
  • Substituents are, for example, linear and branched alkyl groups having from 1 to 6 carbon atoms, for example methyl, ethyl, propyl, butyl, pentyl, 2-methylbutyl or hexyl; cycloalkyl groups, for example cyclopentyl and cyclohexyl; aromatic groups such as phenyl or naphthyl; amino groups, ether groups, ester groups and halides.
  • aromatic groups denote radicals of mono- or polycyclic aromatic compounds having preferably from 6 to 20, in particular from 6 to 12, carbon atoms.
  • Heteroaromatic groups denote aryl radicals in which at least one CH group has been replaced by N and/or at least two adjacent CH groups have been replaced by S, NH or O, heteroaromatic groups having from 3 to 19 carbon atoms.
  • Aromatic or heteroaromatic groups preferred in accordance with the invention derive from benzene, naphthalene, biphenyl, diphenyl ether, diphenylmethane, diphenyldimethylmethane, bisphenone, diphenyl sulfone, thiophene, furan, pyrrole, thiazole, oxazole, imidazole, isothiazole, isoxazole, pyrazole, 1,3,4-oxadiazole, 2,5-diphenyl-l,3,4-oxadiazole, 1,3,4-thiadiazole, 1,3,4-triazole, 2,5-diphenyl- 1,3,4-triazole, l,2,5-triphenyl-l,3,4-triazole, 1,2,4-oxadiazole, 1,2,4-thiadiazole, 1,2,4-triazole, 1,2,3-triazole, 1,2,3,4-tetrazole, benzo[b
  • the preferred alkyl groups include the methyl, ethyl, propyl, isopropyl, 1 -butyl, 2-butyl, 2-methylpropyl, tert-butyl radical, pentyl, 2-methylbutyl,
  • the preferred cycloalkyl groups include the cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and the cyclooctyl group, each of which is optionally substituted with branched or unbranched alkyl groups.
  • the preferred alkenyl groups include the vinyl, allyl, 2-methyl-2-propenyl, 2-butenyl, 2-pentenyl, 2-decenyl and the 2-eicosenyl group.
  • the preferred alkynyl groups include the ethynyl, propargyl, 2-methyl- 2-propynyl, 2-butynyl, 2-pentynyl and the 2-decynyl group.
  • the preferred alkanoyl groups include the formyl, acetyl, propionyl,
  • the preferred alkoxycarbonyl groups include the methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, tert-butoxycarbonyl,
  • the preferred alkoxy groups include alkoxy groups whose hydrocarbon radical is one of the aforementioned preferred alkyl groups.
  • the preferred cycloalkoxy groups include cycloalkoxy groups whose hydrocarbon radical is one of the aforementioned preferred cycloalkyl groups.
  • the preferred heteroatoms which are present in the R 4 radical include oxygen, nitrogen, sulfur, boron, silicon and phosphorus, preference being given to oxygen and nitrogen.
  • the R 4 radical comprises at least two, preferably at least three, heteroatoms.
  • the R 4 radical in ester compounds of the formula (II) preferably has at least 2 different heteroatoms.
  • the R 4 radical in at least one of the ester compounds of the formula (II) may comprise at least one nitrogen atom and at least one oxygen atom.
  • At least one heteroatom in the R 4 radical in at least one of the ester compounds of the formula (II) may be separated from the X group by at least 4 atoms, more preferably by at least 6 atoms.
  • the R 4 radical in at least one of the ester compounds of the formula (II) may comprise at least one group of the formula - CO- and at least one nitrogen atom.
  • the R 4 radical in at least one of the ester compounds of the formula (II) may have at least one urea group, urea groups generally being representable by the formula -NR b -CO-NR c - in which the R b and R c radicals are each independently hydrogen or a group having from 1 to 40 carbon atoms, preferably from 1 to 20 carbon atoms and more preferably from 1 to 4 carbon atoms, or the radicals R b and R c radicals may form a ring having from 1 to 80 carbon atoms.
  • the R 4 radical in at least one ester compound of the formula (II) is most preferably of a group of the formula (III):
  • A is a connecting group having from 1 to 500 carbon atoms, preferably from 1 to 50 carbon atoms, and more preferably from 1 to 10 carbon atoms.
  • the expression "connecting group having from 1 to 500 carbon atoms" has already been explained in detail above.
  • A is an alkoxyalkylene alkylene group containing from 1 to 10 and preferably from 1 to 6, more preferably from 2 to 4 carbon atoms.
  • A is most preferably an alkylene group having from 2 to 4 carbon atoms.
  • said statistical copolymer is derived essentially from at least one monomer (b) of the formula (IV):
  • the most preferred monomer (b) comprises N-(2- methacryloyloxyethyl)ethyleneurea (2-(2-oxo- 1 -imidazolidinyl)ethyl 2-methyl-2- propenoate).
  • the copolymer is essentially derived from co-monomers (a) and (b) (as defined above) and additionally one or more further co-monomers (c), wherein the or each co-monomer (c) is an ethylenically unsaturated compound different from either (a) or (b) defined above.
  • co-polymers may have additional performance features imparted to them by the incorporation therein of such additional co-monomers (c).
  • Copolymers derived essentially from co-monomers (a) and (b) (as defined above in relation to all aspects) and additionally one or more co-monomers (c) are particularly preferred for imparting the dual properties of dynamic friction increase and viscosity index improvement to the resulting lubricant composition.
  • the or each co-monomer (c) in this embodiment is an alkyl acrylate or methacrylate wherein, preferably, the alkyl substituent is a straight chain or branched chain alkyl group, preferably having from 1 to 5 carbon atoms.
  • the statistical copolymers generally have a molecular weight in the range from 1,000 to 1,000,000 g/mol, preferably in the range from 10 x 10 3 to 500 x 10 3 g/mol and more preferably in the range from 20 x 10 3 to 300 x 10 3 g/mol.
  • the values are based on the weight-average molecular weight of the polydisperse polymers in the composition. This parameter is determined by GPC as measured against the earlier- described standards.
  • said statistical copolymer has a weight-average molecular weight, Mw, as measured by GPC as measured against the earlier-described standards within the range of 10,000 to 100,000 g/mol. More preferably, said statistical copolymer has a weight-average molecular weight, Mw, as measured by GPC as measured against the earlier-described standards within the range of 10,000 to 60,000 g/mol.
  • the preferred copolymers which can be obtained by polymerizing unsaturated ester compounds preferably have a polydispersity M w /M n in the range from 1.05 to 4.0. This parameter can also be determined by GPC as measured against the earlier- described standards.
  • polyalkyl esters from the above-described compositions
  • these polymers can be effected especially by free- radical polymerization, and also related processes; for example controlled radical polymerization processes such as ATRP (Atom Transfer Radical Polymerization) when applied to starting mixtures of co-monomers.
  • ATRP Atom Transfer Radical Polymerization
  • Such preparation methods are known in the art.
  • the polymerization is preferably carried out in a nonpolar solvent.
  • nonpolar solvent include hydrocarbon solvents, for example aromatic solvents such as toluene, benzene and xylene, saturated hydrocarbons, for example cyclohexane, heptane, octane, nonane, decane, dodecane, which may also be present in branched form.
  • hydrocarbon solvents for example aromatic solvents such as toluene, benzene and xylene, saturated hydrocarbons, for example cyclohexane, heptane, octane, nonane, decane, dodecane, which may also be present in branched form.
  • solvents may be used individually and as a mixture.
  • Particularly preferred solvents are mineral oils, natural oils and synthetic oils, and also mixtures thereof. Among these, very particular preference is given to mineral oils.
  • the monomer units originating from monomer (b) preferably constitute from 1 to 10 weight percent of the total weight of said statistical copolymer. More preferably, the monomer units originating from monomer (b) constitute from 4 to 8 weight percent of the total weight of said statistical copolymer.
  • the monomer units originating from monomer (a) constitute at least 90 weight percent of the total weight of said statistical copolymer. More preferably, the monomer units originating from monomer (a) constitute the remainder of said statistical copolymer.
  • the monomer units originating from monomer (b) constitute from 1 to 6 weight percent of the total weight of said statistical copolymer , wherein said statistical copolymer has a weight-average molecular weight, Mw, as measured by GPC against the earlier-described standards within the range of 40,000 to 60,000 g/mol.
  • component i.b illustrate the preparation of poly(alkyl methacrylates) useful in the invention.
  • a 5 L reactor equipped with a reflux condenser, mechanical stirrer, and thermocouple was charged at room temperature with the monomer mixture, butyl acetate and dodecylmercaptan (Initial charge).
  • the reaction mixture was inerted under nitrogen for 15min and heated to 100°C.
  • the polymerization initiator was added over the course of 60 minutes (Feed).
  • the mixture was held at temperature for 60 minutes, after which the replenishment of initiator was added completely
  • a 5 L reactor equipped with a reflux condenser, mechanical stirrer, and thermocouple was charged at room temperature with the monomer mixture, butyl acetate and dodecylmercaptan (Initial charge).
  • the reaction mixture was inerted under nitrogen for 15min and heated to 100°C.
  • the polymerization initiator was added over the course of 60 minutes (Feed).
  • the mixture was held at temperature for 60 minutes, after which the replenishment of initiator was added completely
  • a I L reactor equipped with a reflux condenser, mechanical stirrer, and thermocouple was charged at room temperature with the monomer mixture, butyl acetate and 30min and heated to 100°C. At 100°C, the polymerization initiator was added over the course of 60 minutes (Feed). The mixture was held at temperature for 60 minutes, after which the replenishment of initiator was added completely
  • a 5 L reactor equipped with a reflux condenser, mechanical stirrer, and thermocouple was charged at room temperature with 100N oil (Initial charge).
  • the reaction mixture was inerted under nitrogen for 15min and heated to 100°C.
  • the monomer mixture, dodecylmercaptan, and intiator were added over the course of 120 minutes (Feed).
  • the mixture was held at temperature for 30 minutes, after which the replenishment of initiator was added completely (Replenishment step).
  • the mixture was continually held for 60 minutes. Afterwards, the product was further diluted in oil to achieve the final product (Dilution).
  • the lubricant composition resulting from step (i) additionally comprises (i.c) an ashless dispersant, wherein said dispersant is present in an amount that is effective in combination with the copolymer (i.b) to increase the dynamic coefficient of friction of the lubricant composition.
  • the added presence of the dispersant imparts a higher dynamic coefficient of friction to the oil than that obtained through addition of the copolymer alone.
  • the monomer units originating from monomer (b) preferably constitute from 6 to 10 weight percent of the total weight of said statistical copolymer , and said statistical copolymer preferably has a weight- average molecular weight, Mw, as measured by GPC against the earlier-described standards within the range of 10,000 to 40,000 g/mol.
  • the ashless dispersant comprises one or more alkenyl- or polyalkenyl-substitututed succinimide or succinamide compounds.
  • the ashless dispersant consists of one or more alkenyl- or polyalkenyl- substitututed succinimide or succinamide compounds derived from polyalkylene polyamines.
  • Ashless dispersants useful in the practice of the present invention include hydrocarbyl succinimides, hydrocarbyl succinamides, mixed ester/amides of hydrocarbyl-substituted succinic acid, hydroxy esters of hydrocarbyl-substituted succinic acid, and Mannich condensation products of hydrocarbyl-substituted phenols, formaldehyde and polyamines. Also useful are condensation products of polyamines and hydrocarbyl substituted phenyl acids. Mixtures of these dispersants can also be used.
  • the preferred dispersants are the alkenyl succinimides and succinamides.
  • the succinimide or succinamide dispersants can be formed from amines containing basic nitrogen and additionally one or more hydroxy groups.
  • the amines are polyamines such as polyalkylene polyamines, hydroxy-substituted polyamines and polyoxyalkylene polyamines. Examples of polyalkylene polyamines include diethylene triamine, triethylene tetramine, tetraethylene pentamine, pentaethylene hexamine.
  • Low cost poly(ethyleneamines) PAM's
  • PAM Low cost poly(ethyleneamines) averaging about 5 to 7 nitrogen atoms per molecule are available commercially under trade names such as "Polyamine H", “Polyamine 400", Dow Polyamine E-100", etc.
  • Hydroxy-substituted amines include N-hydroxyalkyl-alkylene polyamines such as N-(2-hydroxyethyl)ethylene diamine, N-(2-hydroxyethyl)piperazine, and N-hydroxyalkylated alkylene diamines of the type described in U.S. Patent No. 4,873,009.
  • Polyoxyalkylene polyamines typically include polyoxyethylene and polyoxypropylene diamines and triamines having average molecular weights in the range of 200 to 2500.
  • the amine is readily reacted with the selected hydrocarbyl-substituted dicarboxylic acid material, e.g., alkylene succinic anhydride, by heating an oil solution containing 5 to 95 wt. % of said hydrocarbyl-substituted dicarboxylic acid material at about 100° to 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 formation of imides or mixtures of imides and amides, rather than amides and salts.
  • Reaction ratios of hydrocarbyl- substituted dicarboxylic acid material to equivalents of amine as well as the other nucleophilic reactants described herein can vary considerably, depending on the reactants and type of bonds formed. Generally from 0.1 to 1.0, preferably from about 0.2 to 0.6 (e.g., 0.4 to 0.6), equivalents of dicarboxylic acid unit content (e.g., substituted succinic anhydride content) is used per reactive equivalent of nucleophilic reactant, e.g., amine.
  • a pentamine having two primary amino groups and five reactive equivalents of nitrogen per molecule
  • alkenyl succinimides which have been treated with a borating agent are also suitable for use in the compositions of this invention as they are much more compatible with elastomeric seals made from such substances as fluoro-elastomers and silicon-containing elastomers.
  • Dispersants may also be post-treated with many reagents known to those skilled in the art (see, for example U.S. Patent Nos.
  • the preferred ashless dispersants are polyisobutenyl succinimides formed from polyisobutenyl succinic anhydride and an alkylene polyamine such as triethylene tetramine or tetraethylene pentamine wherein the polyisobutenyl substituent is derived from polyisobutene having a number average molecular weight in the range of 300 to 3000 (preferably 400 to 2500). It has been found that selecting certain dispersants within the broad range of alkenyl succinimides produces fluids with improved frictional characteristics.
  • the most preferred dispersants of this invention are those wherein the polyisobutene substituent group has a molecular weight of approximately 950 atomic mass units, the basic nitrogen containing moiety is polyamine (PAM).
  • the ashless dispersants of the invention can be used in any amount that is effective to improve the dynamic coefficient of friction of the lubricant composition when present therein in addition to the above-defined copolymers.
  • the ashless dispersants are typically used from about 0.1 to about 10.0 mass % in the finished lubricant, preferably from about 0.5 to about 7.0 mass %, and most preferably from about 2.0 to about 5.0 mass %.
  • the co-operation between the copolymer and the ashless dispersant in increasing friction manifests itself in the achievement of friction increases that are greater than those achieved by the same amount of copolymer when used alone.
  • the lubricant composition resulting from step (i) additionally comprises one or more performance enhancing additive packages.
  • the function of the performance additive package is to confer more desirable friction characteristics on the finished lubricants. While the presence of the statistical copolymers s themselves increases the level of friction of the fluid, further refinement of the friction properties the fluids may be useful in modern transmissions.
  • the performance additive packages can further improve the level of high speed friction but also concurrently reduce the levels of low speed friction.
  • the slope of the relationship of the friction coefficient at high speed to that at low speed is referred to as the d ⁇ /dv of the fluid.
  • Stick-slip in automotive clutches is commonly referred to as shudder and is felt by the operator as a vibration in the vehicle (see for example: R.F. Watts and R.K. Nibert, "Prediction of Low Speed Clutch Shudder in Automatic Transmissions Using the Low Velocity Friction Apparatus", 7th International Colloquium on Automotive
  • Performance additive packages useful in the present invention are well known to those skilled in the art. They are concentrates consisting of mixtures of additive chemicals such as anti-wear agents, anti-oxidants, friction modifiers, inhibitors, detergents, etc., that when treated at appropriate dosages in lubricating base oils confer desirable properties to the resulting lubricant. In the case of the present invention these additive packages would be those capable of producing automatic transmission fluids (ATFs), continuously variable transmission fluids (CVTFs), dual clutch transmission fluids (DCTFs) and other fluids that are commonly used in conjunction with oil lubricated oil-lubricated clutches.
  • ATFs automatic transmission fluids
  • CVTFs continuously variable transmission fluids
  • DCTFs dual clutch transmission fluids
  • the additive packages suitable for use in this invention would all contain ashless dispersants as described above.
  • Examples of these types of performance additive packages would be: Infineum T4575, Infineum T4904 and Infineum T4300 (available from Infineum, USA, Linden, New Jersey, USA); Hitec 2038, Hitec 2435 and Hitec 3491 (available from Afton, Inc., Richmond, Virginia, US); Lubrizol 9680, Lubrizol 6373 and Lubrizol DCT 03 VW (available from the Lubrizol Corporation, Wickliffe, Ohio, USA). These performance additive packages generally treat from about 5.0 to about 20.0 mass percent in the lubricating base fluid mixture.
  • the at least one statistical copolymer is preferably that statistical copolymer defined above, and preferably that statistical copolymer defined in any of claims 2 to 8 inclusive, 10, or 15 to 20 inclusive below.
  • the ashless dispersant comprises one or more alkenyl- or polyalkenyl-substituted succinimide or succinamide compounds, and more preferably consists of one or more alkenyl- or polyalkenyl-substitututed succinimide or succinamide compounds derived from polyalkylene polyamines.
  • said clutch is utilised in a power-transmission device, and said device is a vehicular automatic transmission.
  • said automatic transmission is of a type selected from the group consisting of stepped automatic transmissions, automated manual transmissions, continuously variable transmissions and dual clutch transmissions.
  • the oil-lubricated clutches of the invention are commonly used friction clutches made of alternating steel reaction plates and steel plates coated with a composite material which when sliding relative to each other provide high friction coefficients and act as brakes.
  • the composite coating, or lining is often based of a cellulosic paper which can then be impregnated with various minerals or particles, such as graphite and diatomaceous earth, to further modify the frictional
  • the lining is further coated with, or saturated with, a resin, e.g. phenolic or silicate polymer, to give it mechanical strength and wear resistance.
  • a resin e.g. phenolic or silicate polymer
  • Comparative example B-C-1 is the 'control' test derived simply from the monomer (a) component (mixture of C12-C15 methacrylates). Direct comparison of B-C-1 particularly with examples B-2 and B-4 (all having the same Mw of 20,000 g/mol) shows the impact of monomer (b) on increasing the dynamic coefficient of friction.
  • B-3 exhibited the optimum performance of the polymers per se, corresponding to the preferred combination of low monomer (b) content (within the range of 1 to 6 percent by weight) and molecular weight within the range of 40,000 to 60,000 g/mol.
  • Dispersant A is a PIBSA-Polyamine adduct produced from a polyisobutylene of 2225 molecular weight which is post treated with boric acid.
  • Dispersant B is a PIBSA-Polyamine adduct produced from polyisobutylene of 950 molecular weight. Both ashless dispersants were simply added to the solutions of poly(alkyl methacrylates) at 1.65 mass percent active ingredient.

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  • Lubricants (AREA)

Abstract

L'invention concerne un procédé d'augmentation du coefficient dynamique de frottement dans un embrayage à friction lubrifié à l'huile au moyen d'une huile de lubrification contenant au moins un copolymère spécifique dont la présence crée des niveaux de frottement dynamique élevés dans l'embrayage.
PCT/IB2014/001586 2013-03-13 2014-03-11 Procédé d'utilisation de coefficients de frottement élevés sur des embrayages à friction lubrifiés à l'huile WO2015056062A1 (fr)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5620948A (en) * 1995-05-18 1997-04-15 The Lubrizol Corporation Additive combinations for lubricants and functional fluids
US20080146475A1 (en) * 2005-04-06 2008-06-19 Rohmax Additives Gmbh Polyalkyl (Meth) Acrylate Copolymers Having Outstanding Properties
WO2008094781A2 (fr) * 2007-01-30 2008-08-07 The Lubrizol Corporation Combinaison dispersante pour fluides de transmission améliorés
WO2011102835A1 (fr) * 2010-02-19 2011-08-25 Toyota Jidosha Kabushiki Kaisha Systèmes lubrifiants pour embrayages à friction humide fournissant des coefficients de frottement dynamique élevés par l'utilisation de détergents au sodium

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3785378B2 (ja) * 2002-04-30 2006-06-14 出光興産株式会社 自動変速機用潤滑油組成物

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5620948A (en) * 1995-05-18 1997-04-15 The Lubrizol Corporation Additive combinations for lubricants and functional fluids
US20080146475A1 (en) * 2005-04-06 2008-06-19 Rohmax Additives Gmbh Polyalkyl (Meth) Acrylate Copolymers Having Outstanding Properties
WO2008094781A2 (fr) * 2007-01-30 2008-08-07 The Lubrizol Corporation Combinaison dispersante pour fluides de transmission améliorés
WO2011102835A1 (fr) * 2010-02-19 2011-08-25 Toyota Jidosha Kabushiki Kaisha Systèmes lubrifiants pour embrayages à friction humide fournissant des coefficients de frottement dynamique élevés par l'utilisation de détergents au sodium

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