Lubricating composition and method of lubricating internal combustion engine

Abstract

The disclosed technology relates to lubricants for compression ignition internal combustion engines, in particular those exhibiting at least one of improved sealing performance, reduced deposit formation, and excellent durability. The present invention provides a low zinc lubricating composition comprising (a) an oil of lubricating viscosity, (b) a borated dispersant; and (c) a metal-free organophosphorus antiwear additive, wherein the lubricating composition is substantially free of metal sulfur-containing coupled alkylphenol compounds. Further, the low zinc lubricating composition contains zinc in an amount of less than 600 ppm by weight of the composition.

Description

Background Art

[0001] The disclosed technology relates to lubricants for internal combustion engines.

[0002] Lubrication of internal combustion engines has been a practice for decades, but lubrication technology continues to improve as new engines and standards are developed. For example, formulations for spark-ignition and compression-ignition engines must address restrictions on sulfated ash, phosphorus, and sulfur ("SAPS") content, and restrictions on these ingredients often result in an upper limit on the amount of metal-containing additives that can be included in the lubricant. Reducing metal-containing additives is necessary to reduce the impact of metallic ash on exhaust aftertreatment devices and reduce particulate matter emissions.

[0003] These metal-containing additives are primarily zinc dialkyl dithiophosphates (ZDDP) for wear and oxidation protection and overbased metal detergents for cleaning and acid control. ZDDP has become the industry standard for reducing valvetrain wear, preventing bushing wear, and reducing oxidation-induced corrosive wear. However, zinc contributes to increased sulfated ash in the lubricant, while phosphorus deactivates oxidation catalysts used in exhaust aftertreatment devices.

[0004] The disclosed technology provides a lubricating composition containing an alternative additive to ZDDP or suitable for use in a low zinc lubricant composition, wherein the composition provides deposit and / or oxidation control during operation of an internal combustion engine. Summary of the invention

[0005] The present invention provides a composition for lubricating an internal combustion engine, comprising an oil of lubricating viscosity and a 2,5-dimercapto-1,3,4-thiadiazole ("DMTD") derivative additive, the DMTD derivative additive being the reaction product of DMTD and an α,β-unsaturated carbonyl compound.

[0006] In one embodiment, the present invention provides a composition for lubricating an internal combustion engine, comprising an oil having a lubricating viscosity and a DMTD derivative additive, the DMTD derivative additive being the reaction product of DMTD and an α, β-unsaturated carbonyl compound (such as an ester, amide or imide). In another embodiment, the present invention provides a composition for lubricating an internal combustion engine, comprising an oil having a lubricating viscosity and a DMTD derivative additive, the DMTD derivative additive being the reaction product of DMTD and an α, β-unsaturated ester. In another embodiment, the present invention provides a composition for lubricating an internal combustion engine, the composition comprising an oil having a lubricating viscosity and a DMTD derivative additive, the DMTD derivative additive being the reaction product of DMTD and an α, β-unsaturated ester, wherein the α, β-unsaturated ester is selected from the group consisting of: maleate, acrylate, methacrylate, fumarate, crotonate, itaconate and mixtures thereof. In some embodiments, the DMTD derivative additive is a metal salt or amine salt of the reaction product of DMTD and an α, β-unsaturated carbonyl compound.

[0007] The present invention also provides a method for lubricating an internal combustion engine, the method comprising providing a lubricating composition comprising an oil of lubricating viscosity and a DMTD derivative additive to the engine, the DMTD derivative additive being a reaction product of DMTD and an α,β-unsaturated carbonyl compound or a salt thereof.

[0008] The present invention also provides a method for decomposing peroxides in a lubricating composition by operating an engine having the lubricating composition when the lubricating composition is used to lubricate an internal combustion engine, wherein the lubricating composition comprises an oil of lubricating viscosity and a DMTD derivative additive, wherein the DMTD derivative additive is a reaction product of DMTD and an α,β-unsaturated carbonyl compound or a salt thereof.

[0009] The present invention also provides the use of a lubricating composition comprising an oil of lubricating viscosity and a DMTD derivative additive which is a reaction product of DMTD and an α,β-unsaturated carbonyl compound or a salt thereof for oxidation and deposit control in an internal combustion engine. DETAILED DESCRIPTION

[0010] Various preferred features and embodiments will be described below by way of non-limiting illustration.

[0011] Oil of lubricating viscosity

[0012] The lubricating composition comprises an oil with lubricating viscosity. Such oils include natural oils and synthetic oils, oils derived from hydrocracking, hydrogenation and hydrofining, unrefined oils, refined oils, re-refined oils or mixtures thereof. A more detailed description of unrefined oils, refined oils and re-refined oils is provided in paragraphs

[0054] to

[0056] of International Publication WO2008 / 147704 (similar disclosures are provided in U.S. Patent Application 2010 / 197536, see

[0072] to

[0073] ). A more detailed description of natural lubricating oils and synthetic lubricating oils is described in paragraphs

[0058] to

[0059] of WO2008 / 147704, respectively (similar disclosures are provided in U.S. Patent Application 2010 / 197536, see

[0075] to

[0076] ). Synthetic oils may also be produced by the Fischer-Tropsch reaction and may typically be hydroisomerized Fischer-Tropsch hydrocarbons or waxes. In one embodiment, the oil may be produced by a Fischer-Tropsch gas-to-liquid synthesis process as well as other gas-to-liquid oils.

[0013] Oils of lubricating viscosity may also be defined as specified in subsection 1.3 of "Appendix E - API Base Oil Interchangeability Guidelines for Passenger Car Motor Oils and Diesel Engine Oils" April 2008 edition. The API guidelines are also summarized in U.S. Patent No. 7,285,516 (see column 11, line 64 to column 12, line 10). In one embodiment, the oil of lubricating viscosity may be an APIII, III or IV oil or a mixture thereof. Five base oils are classified as follows:

[0014]

[0015] The amount of oil of lubricating viscosity is generally the balance remaining after subtracting the sum of the amounts of the compound of the present invention and other performance additives from 100 weight percent (wt %).

[0016] The lubricating composition may be in the form of a concentrate and / or in the form of a fully formulated lubricant. If the lubricating composition of the present invention (including the additives disclosed herein) is in the form of a concentrate that can be combined with additional oils to form all or part of a finished lubricant, the ratio of these additives to the oil of lubricating viscosity and / or diluent oil includes a range of 1:99 to 99:1 by weight or 80:20 to 10:90 by weight.

[0017] In one embodiment, the kinematic viscosity of the base oil at 100°C is 2 mm2 / s(centistoke-cSt) to 16mm 2 / s、3mm 2 / s to 10mm 2 / s, or even 4mm 2 / s to 8mm 2 / s.

[0018] In one embodiment, the base oil comprises at least 30% by weight of a Group II or Group III base oil. In another embodiment, the base oil comprises at least 60% by weight of a Group II or Group III base oil, or at least 80% by weight of a Group II or Group III base oil. In one embodiment, the lubricant composition comprises less than 20% by weight of a Group IV (i.e., polyalphaolefin) base oil. In another embodiment, the base oil comprises less than 10% by weight of a Group IV base oil. In one embodiment, the lubricating composition is substantially free of (i.e., contains less than 0.5% by weight) a Group IV base oil.

[0019] Ester-based fluids, known as Group V oils, have very high solvency levels due to their polar nature. Adding low levels (typically less than 10% by weight) of esters to lubricating compositions can significantly increase the solvency of the resulting base oil blend. Esters can be broadly divided into two categories: synthetic esters and natural esters. Ester-based fluids have a kinematic viscosity at 100°C suitable for engine oil lubricants, such as between 2 cSt and 30 cSt, or 3 cSt to 20 cSt, or even 4 cSt to 12 cSt.

[0020] Synthetic esters may include esters of any of dicarboxylic acids (e.g., phthalic acid, succinic acid, alkylsuccinic and alkenylsuccinic acids, maleic acid, azelaic acid, suberic acid, sebacic acid, fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkylmalonic and alkenylmalonic acids) with a variety of monohydric alcohols (e.g., butanol, hexanol, dodecanol, 2-ethylhexanol, ethylene glycol, diethylene glycol monoether, and propylene glycol). Specific examples of these esters include dibutyl adipate, di(2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate, 2-ethylhexyl diester of linoleic acid dimer, and a complex ester formed by reacting 1 mole of sebacic acid with 2 moles of tetraethylene glycol and 2 moles of 2-ethylhexanoic acid. Other synthetic esters include esters prepared from C5 to C12 monocarboxylic acids and polyols and polyol ethers such as neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol and tripentaerythritol. The ester may also be a monoester of a monocarboxylic acid and a monool.

[0021] Natural (or biologically derived) ester refers to a substance derived from a renewable biological resource, an organism or an entity, which is different from a substance derived from oil or an equivalent raw material. Natural fats include fatty acid triglycerides, hydrolyzed or partially hydrolyzed triglycerides or triglycerides through transesterification, such as fatty acid methyl esters (or referred to as FAME). Suitable triglycerides include but are not limited to palm oil, soybean oil, sunflower oil, rapeseed oil, olive oil, linseed oil and related substances. Other sources of triglycerides include but are not limited to algae, animal fats and zooplankton. The method for producing biolubricants by natural triglycerides is described in, for example, U.S. Patent Application 2011 / 0009300A1.

[0022] In one embodiment, the lubricating composition comprises at least 2 wt% ester-based fluid. In one embodiment, the lubricating composition of the present invention comprises at least 4 wt% ester-based fluid, or at least 7 wt% ester-based fluid, or even 10 wt% ester-based fluid.

[0023] Dithiothiadiazole derivatives additives

[0024] Dimercaptodithiadiazole (DMTD herein) can be derivatized from the reaction product of Michael addition of an α,β-unsaturated carbonyl compound and DMTD, i.e., 1,4 addition of DMTD to a carbonyl compound such as an ester group, amide group, imide group capable of 1,4 addition.

[0025] Although the reaction products for preparing the derivatives generally produce product mixtures, the products can also be provided as pure compounds. Generally speaking, the DMTD derivatives can be represented in pure form by Formula I:

[0026] Formula I

[0027]

[0028] in

[0029] "X" is a metal, an amine, or H;

[0030] wherein "Y" is a group derived from a carboxylate such as an itaconate, a maleate, a fumarate or a (meth)acrylate; and

[0031] n is 1, 2, 3 or 4.

[0032] The metal may include a transition metal such as zinc, titanium, cobalt, zirconium, manganese or molybdenum, for example a post-transition metal and even some metalloids such as, for example, aluminum, antimony or boron. When a salt is desired, it may be obtained by 1,4 addition to an ester monomer followed by reaction with a metal oxide or hydroxide. In some embodiments, DMTD may be substantially free of antimony or free of antimony.

[0033] In one embodiment, the carbonyl compound is a carboxylate group capable of 1,4 addition. Those skilled in the art can easily think of such carboxylate groups capable of 1,4 addition (i.e., α, β-unsaturated carbonyl compounds), and the carboxylate group includes monocarboxylates and dicarboxylates and higher carboxylates, such as tricarboxylates, tetracarboxylates, etc. Generally speaking, the carboxylate can be a C4 to C24 carboxylate, or a C5 to C22 carboxylate, or a C6 to C20 carboxylate, or even a C6 to C18 carboxylate. In some cases, C6 to C12 carboxylates or even C6 to C10 carboxylates and even C8 to C12 carboxylates are usually sufficient. Example carboxylates may include, but are not limited to, itaconates, citraconates, maleates, fumarates, mesaconates, and (meth)acrylates (wherein the brackets "()" around (methyl) indicate that the methyl group may or may not be present). In the present invention, the carboxylate is in the form of an ester.

[0034] In another embodiment, the carbonyl compound may be in the form of an amide or an imide.

[0035] As used herein, the term "group", such as in a (meth)acrylate group, refers to the structure of the group itself or the structure formed after the group reacts with another compound, depending on the context. For example, a methyl group, or as another example, methyl acrylate, can refer to CH2=CHC(O)OCH3 in isolation or -CH2CH2C(O)OCH3 in bonded form.

[0036] Examples of DMTD derivatives may include DMTD derivatives produced by 1,4 addition between DMTD and methacrylate, for example, wherein the substituent Y of the DMTD derivative of Formula I may be, for example, a methyl methacrylate group, for example, represented by Formula II:

[0037] Formula II

[0038]

[0039] In the foregoing example, the DMTD derivative may also be salified, for example by reacting Formula II with a half molar equivalent of a metal oxide or hydroxide (such as zinc oxide) to form, for example, a compound represented by Formula IIa:

[0040] Formula IIa

[0041]

[0042] Another example may include a DMTD derivative produced by 1,4 addition between DMTD and acrylate, wherein the substituent Y of the DMTD derivative of Formula I may be, for example, a 2-ethylhexyl acrylate group, such as represented by Formula III:

[0043] Formula III

[0044]

[0045] Salts of the aforementioned formulae can be prepared by reaction with a metal hydroxide such as, for example, titanium alkoxide to obtain salts of the following formula IIIa.

[0046] Formula IIIa

[0047]

[0048] Yet another example may include a DMTD derivative produced by 1,4 addition between DMTD and maleate, wherein the substituent Y of the DMTD derivative of Formula I may be, for example, a diethylhexyl maleate group, for example, represented by Formula IV:

[0049] Formula IV

[0050]

[0051] Salts of the aforementioned formula can be prepared by reaction with a metal oxide such as, for example, antimony oxide to obtain salts of the following formula IVa.

[0052] Formula IVa

[0053]

[0054] Further examples may include DMTD derivatives produced by 1,4 addition between DMTD and dialkyl itaconate (such as dimethyl itaconate, dimethyl citrate, dimethyl fumarate, dimethyl mesaconic acid, and the like).

[0055] Other embodiments may include DMTD derivatives salted with amine compounds produced by Michael addition of α,β-unsaturated carbonyl compounds and DMTD. Amines that may be suitable for use as amine salts include mono-, di- or tri-substituted amines, preferably secondary and tertiary amines. Specific examples include primary alkylamines such as methylamine, ethylamine, n-propylamine, n-butylamine, n-hexylamine, n-octylamine, 2-ethylhexylamine, benzylamine, 2-phenylethylamine, coconut amine, oleylamine and tridecylamine (CAS#86089-17-0); secondary and tertiary alkylamines such as isopropylamine, sec-butylamine, tert-butylamine, tert-hexylamine, 1-methyl-1-amino-cyclohexane, tert-octylamine, tert-decylamine, tert-dodecylamine, tert-tetradecylamine, tert-hexadecylamine, tert-octadecylamine, tert-tetradecylamine and tert-octadecylamine, cyclopentylamine, cyclohexylamine and 1-phenylethylamine; dialkylamines such as dimethylamine, diethylamine, dipropylamine, dipropylamine, dibutyl ... cycloalkylamines such as piperidine, N-ethylpiperidine, N,N"-dimethylpiperazine, morpholine, N-methylmorpholine, N-ethylmorpholine, N-methylpiperidine, pyrrolidine, N-methylpyrrolidine and N-ethylpyrrolidine; and trialkylamines such as tetramethylethylenediamine, trimethylamine, triethylamine, tripropylamine, triisopropylamine, tributylamine, trihexylamine, N,N-dimethylbenzylamine, dimethylethylamine, dimethylisopropylamine, dimethylbutylamine and N,N-dimethylcyclohexylamine.

[0056] The DMTD derivatives can be used in automotive lubricants or industrial lubricants at 0.05 wt % to 2 wt %, or 0.08 wt % to 1.8 wt %, or even 0.1 wt % to 1.6 wt %, or 0.12 wt % to 1.4 wt %, or even 0.15 wt % to 1.2 wt %, or even 0.4 wt % to 1 wt %. In another embodiment, the DMTD derivative is present in an amount that delivers at least 0.05 wt % to 0.35 wt %, or 0.07 wt % to 0.3 wt %, or 0.08 wt % to 0.26 wt % sulfur to the lubricating composition.

[0057] Likewise, DMTD derivatives may be used in automotive or industrial lubricants sufficient to provide 100 ppm to 5000 ppm sulfur, or even 250 ppm to 4000 ppm sulfur or 500 ppm to 3000 ppm sulfur, or even 750 ppm to 2500 ppm sulfur or 1050 ppm to 2000 ppm sulfur.

[0058] Other additives

[0059] The composition of the present invention may optionally contain one or more other additional performance additives. These additional performance additives may include, but are not limited to, one or more dispersants, including borated dispersants, anti-wear additives, detergents, metal deactivators, viscosity modifiers, detergents, friction modifiers, anti-wear agents, corrosion inhibitors, dispersant viscosity modifiers, extreme pressure agents, antioxidants, foam inhibitors, demulsifiers, pour point depressants, seal expansion agents, and any combination or mixture thereof. Typically, a fully formulated lubricating oil will contain one or more of these performance additives, and typically contain a set of multiple performance additives.

[0060] In one embodiment, the lubricating composition of the present invention may contain a borated dispersant. The borated dispersant may be a succinimide dispersant, a Mannich dispersant, a polyolefin succinate, an amide or an ester-amide or a mixture thereof obtained by boration with one or more of various agents, the one or more agents being selected from the group consisting of various forms of boric acid (including metaboric acid HBO2, orthoboric acid H3BO3 and tetraboric acid H2B4O7), boric oxide, boron trioxide and alkyl borates. In one embodiment, the borated agent is boric acid, which may be used alone or in combination with other borated agents. Methods for preparing borated dispersants are known in the art. The borated dispersant may be prepared in such a manner that the borated agent contains 0.1 wt % to 2.5 wt % boron, or 0.1 wt % to 2.0 wt % boron, 0.2 wt % to 1.5 wt % boron, 0.3 wt % to 1.0 wt % boron.

[0061] In one embodiment, the borated dispersant can be a borated succinimide dispersant. The succinimide dispersant can be a derivative of an aliphatic polyamine or a mixture thereof. The aliphatic polyamine can be an aliphatic polyamine such as ethylene polyamine, propylene polyamine, butylene polyamine or a mixture thereof. In one embodiment, the aliphatic polyamine can be an ethylene polyamine. In one embodiment, the aliphatic polyamine can be selected from the group consisting of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, polyamine bottom residues and mixtures thereof.

[0062] The succinimide dispersant can be an aromatic amine, a derivative of an aromatic polyamine, or a mixture thereof. The aromatic amine can be 4-aminodiphenylamine (ADPA) (also known as N-phenylphenylenediamine), a derivative of ADPA (as described in U.S. Patent Publications 2011 / 0306528 and 2010 / 0298185), nitroaniline, aminocarbazole, aminoindazolinone, aminopyrimidine, 4-(4-nitrophenylazo)aniline, or a combination thereof. In one embodiment, the dispersant is a derivative of an aromatic amine, wherein the aromatic amine has at least three non-continuous aromatic rings.

[0063] The succinimide dispersant may be a derivative of a polyetheramine or polyetherpolyamine. Typical polyetheramine compounds contain at least one ether unit and will be chain terminated with at least one amine moiety. The polyetherpolyamine may be based on a polymer derived from a C2-C6 epoxide such as ethylene oxide, propylene oxide and butylene oxide. Examples of polyetherpolyamines are Huntsman® is sold under the trademark Huntsman(R) and is commercially available from Huntsman Corporation in Houston, Texas.

[0064] The borated dispersant may be based on a borated polyisobutylene succinimide dispersant, wherein the borated polyisobutylene succinimide has a number average molecular weight of 350 to 5000, or 550 to 3000, or 750 to 2500, or 350 to 2200, or 350 to 1350, or 350 to 1150, or 350 to 750, or 550 to 2200, or 550 to 1350, or 750 to 2200.

[0065] Suitable polyisobutylenes for the borated polyisobutylene succinimide dispersants may include those formed from polyisobutylene or highly reactive polyisobutylenes having a terminal vinylidene content of at least about 50 mol %, such as about 60 mol %, and particularly about 70 mol % to about 90 mol % or greater than 90 mol %. Suitable polyisobutylenes may include those prepared using a BF3 catalyst. In one embodiment, the borated dispersant is derived from a polyolefin having a number average molecular weight of 350 to 3000 daltons and a vinylidene content of at least 50 mol %, or at least 70 mol %, or at least 90 mol %.

[0066] The dispersant may be prepared / obtained / obtainable from the reaction of succinic anhydride by the so-called "direct alkylation process" via an "ene" reaction or a "thermal" reaction. The "ene" reaction mechanism and general reaction conditions are summarized in Maleic Anhydride, pages 147 to 149, edited by BC Trivedi and BC Culbertson, and published by Plenum Press in 1982. The dispersant prepared by a process involving an "ene" reaction may be a polyisobutylene succinimide having carbocyclic rings present on less than 50 mole %, or 0 to less than 30 mole %, or 0 to less than 20 mole %, or 0 mole % of the dispersant molecules. The reaction temperature of the "ene" reaction may be 180°C to less than 300°C, or 200°C to 250°C, or 200°C to 220°C.

[0067] Dispersants may also be obtained / obtainable by chlorine-assisted processes, typically involving Diels-Alder chemistry resulting in the formation of carbocyclic bonds. Such processes are known to those skilled in the art. Dispersants produced by chlorine-assisted processes may be polyisobutylene succinimide having carbocyclic rings present on 50 mole % or more, or 60 to 100 mole % of the dispersant molecules. Thermal and chlorine-assisted processes are described in more detail in U.S. Pat. No. 7,615,521, columns 4 to 5, and Preparations A and B.

[0068] In one embodiment, the borated dispersant can be a borated polyolefin succinate, amide, or ester-amide. For example, the polyolefin succinate can be a polyisobutylene succinate of pentaerythritol or a mixture thereof. The polyolefin succinate-amide can be polyisobutylene succinic acid reacted with an alcohol such as pentaerythritol and an amine such as a diamine, typically diethylamine.

[0069] The borated dispersants may be used alone or as part of a mixture of borated dispersants. If a mixture of borated dispersants is used, there are two to five or two to three or two borated dispersants.

[0070] The boron-containing dispersant may be present in an amount to deliver at least 25 ppm boron, at least 50 ppm boron, or at least 100 ppm boron to the lubricant composition.

[0071] The borated dispersant typically comprises 0.1 wt % to 10 wt %, or 0.5 wt % to 7 wt %, or 0.8 wt % to 4.5 wt %, or 1.0 wt % to 4.5 wt %, or 2.0 wt % to 4.0 wt %, or 1.5 wt % to 3 wt % of the lubricating oil composition.

[0072] In some embodiments, the lubricating composition may include a non-borated dispersant. The non-borated dispersant may include any non-borated form of the above-mentioned borated dispersants. In one embodiment, the non-borated dispersant may include a polyisobutylene succinimide dispersant, wherein the number average molecular weight of the polyisobutylene is 350 to 5000, or 550 to 3000, or 750 to 2500, or 350 to 2200, or 350 to 1350, or 350 to 1150, or 350 to 750, or 550 to 2200, or 550 to 1350, or 750 to 2200.

[0073] In another embodiment, the non-borated ashless dispersant may include a polyalphaolefin (PAO) containing dispersant selected from the group consisting of polyalphaolefin succinimides, polyalphaolefin succinamides, polyalphaolefin esters, polyalphaolefin oxazolines, polyalphaolefin imidazolines, polyalphaolefin succinamide imidazolines, and combinations thereof.

[0074] The polyalphaolefin (PAO) that can be used as the raw material of the dispersant forming containing PAO is derived from the oligomerization or polymerization of ethylene, propylene and alpha-olefin. Suitable alpha-olefin includes 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene and 1-octadecene. When commercial production PAO, the raw material of the mixture comprising two or more of the aforementioned monomers and other hydrocarbons is usually used. PAO can take the form of dimer, trimer, tetrapolymer, polymer etc.

[0075] The PAO can be reacted with maleic anhydride (MA) to form polyalphaolefin succinic anhydride (PAO-SA), and the anhydride can then be reacted with one or more of polyamines, amino alcohols, and alcohols / polyols to form polyalphaolefin succinimides, polyalphaolefin succinamides, polyalphaolefin succinates, polyalphaolefin oxazolines, polyalphaolefin imidazolines, polyalphaolefin-succinamide-imidazolines, and mixtures thereof.

[0076] The non-borated ashless dispersant may be present at 0.1 wt % to 10 wt %, or 0.5 wt % to 7 wt %, or 1 wt % to 5 wt %, or 1.5 wt % to 4 wt % of the lubricating oil composition.

[0077] The carbonyl to nitrogen ratio (CO:N ratio) in one or both of the borated and non-borated dispersants is from 5:1 to 1:10, 2:1 to 1:10, or 2:1 to 1:5, or 2:1 to 1:2. In one embodiment, the CO:N ratio in the dispersant may be from 2:1 to 1:10, or 2:1 to 1:5, or 2:1 to 1:2, or 1:1.4 to 1:0.6, or 0.9:1 to 1.6:1, or 0.95:1 to 1.5:1, or 1:1 to 1:4.

[0078] In one embodiment, the present invention provides a lubricating composition further comprising a detergent. In one embodiment, the detergent may be an alkali metal or alkaline earth metal sulfonate detergent, an alkali metal or alkaline earth metal salicylate detergent, an alkali metal or alkaline earth metal salixarate detergent, or an alkali metal or alkaline earth metal phenate detergent. The detergent may be a high-alkaline detergent. High-alkaline detergents, also known as high-alkaline salts or super-alkaline salts, are characterized by a metal content that exceeds the metal content required for neutralization according to the stoichiometry of the metal and the specific acidic organic compound that reacts with the metal. High-alkaline detergents are known in the art, and the lubricating composition of the present invention may contain detergents now known or later developed and understood by those skilled in the art to be useful in the present invention.

[0079] In one embodiment, the detergent may include a high-alkalinity metal-containing sulfonate detergent. The high-alkalinity metal-containing sulfonate detergent may include calcium salts, magnesium salts, sodium salts or mixtures thereof of one or more sulfonates. Other useful metals may include titanium and zirconium. The total base number of the high-alkalinity sulfonate generally has a total base number of 250 to 600, or 300 to 500. In one embodiment, the sulfonate detergent may be mainly a linear alkylbenzene sulfonate detergent, and its metal ratio is at least 8, as described in U.S. Patent Publication 2005065045 (and granting U.S. 7407919)

[0026] to

[0037] paragraphs. The linear alkylbenzene sulfonate detergent may be particularly useful for helping to improve fuel economy. The linear alkyl group may be connected to the benzene ring at any position along the straight chain of the alkyl group (but generally at the 2nd, 3rd or 4th position of the straight chain, and in some cases, mainly at the 2nd position), to obtain a linear alkylbenzene sulfonate detergent.

[0080] In one embodiment, the lubricating composition may include an alkali metal or alkaline earth metal salicylate detergent or a salicate detergent or a mixture thereof. The metal salicylate or salicate detergent may be a high alkaline detergent. Useful salicylates and salicate detergents may include calcium salts, magnesium salts, sodium salts or mixtures thereof. Other useful metals may include titanium and zirconium. High alkaline metal salicylate detergents may be present in an amount of 0.1% to 15% by weight, or 0.1% to 10% by weight, or 0.2% to 8% by weight, or 0.2% to 3% by weight. High alkaline metal salicylate detergents may be present in an amount of 0.1% to 15% by weight, or 0.1% to 10% by weight, or 0.2% to 8% by weight, or 0.2% to 3% by weight.

[0081] In one embodiment, the lubricating composition may contain a metal-sulfur-coupled alkylphenol compound. Such compounds may be exemplified by alkali metal and alkaline earth metal-containing phenate detergents such as magnesium phenate detergents, calcium phenate detergents, and sodium phenate detergents and further including overbased metal-containing phenate detergents (all of which are known in the art). In one embodiment, the lubricating composition comprises less than 0.2 wt % or 0.1 wt % or 0.05 wt % or 0.01 wt % or 0.005 wt % of a metal-sulfur-coupled alkylphenol compound.

[0082] In one embodiment, the overbased calcium detergent may be present in an amount to deliver at least 500 ppm of calcium by weight and no more than 3000 ppm of calcium by weight, or at least 1000 ppm of calcium by weight, or at least 2000 ppm of calcium by weight, or at least 1200 ppm of calcium by weight to 1400 ppm of calcium by weight, or no more than 2500 ppm of calcium by weight to the lubricating composition. In one embodiment, the overbased magnesium detergent may be present in an amount to deliver no more than 500 ppm of magnesium by weight, or no more than 330 ppm of magnesium by weight, or no more than 125 ppm of magnesium by weight, or no more than 45 ppm of magnesium by weight to the lubricating composition. In one embodiment, the overbased magnesium detergent may be present in an amount to deliver at least 200 ppm of magnesium by weight, or at least 450 ppm of magnesium by weight, or at least 700 ppm of magnesium by weight to the lubricating composition. In one embodiment, the formulation is free of magnesium or substantially free of magnesium. In one embodiment, a detergent containing both calcium and magnesium may be present in the lubricating composition. Calcium and magnesium detergents may be present such that the weight ratio of calcium to magnesium is from 10:1 to 1:10, or from 8:3 to 4:5, or from 1:1 to 1:3. One or more overbased detergents may be present at 0.1 wt % to 15 wt %, or 0.1 wt % to 10 wt %, or 0.2 wt % to 8 wt %, or 0.2 wt % to 3 wt % of the lubricating composition.

[0083] In one embodiment, wherein the detergent comprises a mixture of calcium-containing detergents and magnesium-containing detergents (such as those disclosed herein), the detergent may provide 800 ppm to 1300 ppm calcium and 450 ppm to 800 ppm magnesium, and in another embodiment 900 ppm to 1200 ppm calcium and 500 ppm to 750 ppm magnesium.

[0084] According to some embodiments, the total amount of soap contributed by the detergent can be from about 0.08 wt % or 1.0 wt % to less than 0.9 wt % or 0.7 wt % or 0.5 wt % or 0.4 wt % or 0.3 wt % or 0.25 wt % relative to the lubricating composition. The lubricating composition can be free of phenate soap or substantially free of phenate soap. As used herein, the term "soap" refers to the surfactant portion of the detergent, excluding metal bases, such as calcium carbonate. The term soap may also be referred to as a detergent matrix. For example, the sulfonate detergent, soap or matrix described herein can be a neutral salt of an alkylbenzene sulfonic acid.

[0085] The metal-containing detergent may also contribute sulfated ash to the lubricating composition. Sulfated ash may be determined by ASTM D874. In one embodiment, the lubricating composition of the present invention comprises a metal-containing detergent in an amount that delivers at least 0.4 wt. % of sulfated ash to the total composition. In another embodiment, the metal-containing detergent is present in an amount that delivers at least 0.6 wt. % of sulfated ash, or at least 0.75 wt. % of sulfated ash, or even at least 0.9 wt. % of sulfated ash to the lubricating composition.

[0086] In some embodiments, the lubricating composition of the present invention may contain an organophosphorus antiwear agent. The organophosphorus antiwear agent may be a metal-free organophosphorus antiwear agent. The organophosphorus agent may contain sulfur or may be sulfur-free. The sulfur-free phosphorus antiwear agent may be a phosphite, a phosphonate, an alkyl phosphate, an amine or an ammonium phosphate or a mixture thereof.

[0087] Phosphorus esters, such as di- and tri-hydrocarbon phosphites, for example dibutyl phosphite, diheptyl phosphite, dicyclohexyl phosphite, pentylphenyl phosphite; dipentylphenyl phosphite, tridecyl phosphite, distearyl phosphite and polypropylene-substituted phenol phosphites; metal thiocarbamates, such as zinc dioctyldithiocarbamate and barium heptylphenol diacid; amine salts or derivatives of alkyl and dialkyl phosphoric acids, including, for example, amine salts of the product of the reaction of a dialkyl dithiophosphoric acid with propylene oxide and subsequent further reaction with P2O5; and mixtures thereof (as described in US 3,197,405).

[0088] The amine phosphate can be an amine salt of (i) a monohydrocarbyl phosphoric acid, (ii) a dihydrocarbyl phosphoric acid, (iii) a hydroxy-substituted phosphoric acid diester, or (iv) a phosphorylated hydroxy-substituted phosphoric acid diester or triester. The amine salt of the sulfur-free phosphorus-containing compound can be a salt of a primary amine, a secondary amine, a tertiary amine, or a mixture thereof.

[0089] Phosphoric acid amine salt can be derived from monoalkyl phosphoric acid or dialkyl phosphoric acid (usually alkyl phosphoric acid) or their mixture.The alkyl of monoalkyl phosphoric acid or dialkyl phosphoric acid can include straight chain or branched alkyl group with 3 to 36 carbon atoms.The alkyl group of straight chain or branched alkyl phosphoric acid can include 4 to 30 or 8 to 20 carbon atoms.The example of the suitable alkyl group of alkyl phosphoric acid can include isopropyl, n-butyl, sec-butyl, amyl, 4-methyl-2-amyl (that is, methyl amyl), n-hexyl, n-heptyl, n-octyl, isooctyl, 2-ethylhexyl, nonyl, 2-propylheptyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, oleyl or their combination.In one embodiment, phosphate is the mixture of single and two (2-ethyl) hexyl phosphate.

[0090] Examples of suitable primary amines include ethylamine, propylamine, butylamine, 2-ethylhexylamine, octylamine and dodecylamine, and fatty amines such as n-octylamine, n-decylamine, n-dodecylamine, n-tetradecylamine, n-hexadecylamine, n-octadecylamine and oleylamine. Other useful fatty amines include commercially available fatty amines such as Amines (commercially available from Akzo Chemicals, Chicago, Ill.) such as Armeen C, Armeen O, Armeen OL, Armeen T, Armeen HT, Armeen S and Armeen SD, wherein the letter designation is associated with a fatty group such as cocoyl, oleyl, tallow or stearyl.

[0091] In one embodiment, the metal-free phosphorus antiwear agent may be present in the lubricating composition in an amount of 0.01 wt % to 5 wt %, or 0.1 wt % to 3.2 wt %, or 0.35 wt % to 1.8 wt %, or 0.5 wt % to 1.5 wt %, or 0.5 wt % to 0.9 wt %. In one embodiment, the metal-free phosphorus antiwear agent may be present in an amount to provide the composition with 0.01 wt % to 0.15 wt % phosphorus, 0.01 wt % to 0.08 wt % phosphorus, or 0.025 wt % to 0.065 wt % phosphorus.

[0092] In another embodiment, the lubricating composition of the present invention is free or substantially free of phosphorus or phosphorus-containing agents.

[0093] In one embodiment, the present invention provides a lubricating composition further comprising an ashless antiwear agent other than the above-mentioned organophosphorus antiwear agent. Examples of suitable antiwear agents include hydroxy-carboxylic acid derivatives such as esters, amides, imides or amines or ammonium salts, sulphurized olefins, thiocarbamate-containing compounds such as thiocarbamates, thiocarbamate amides, thiocarbamate ethers, alkylene coupled thiocarbamates and bis(S-alkyldithiocarbamoyl) disulfides.

[0094] In one embodiment, the ashless antiwear agent may comprise a compound derived from a hydroxycarboxylic acid. In one embodiment, the ashless antiwear agent is derived from at least one of a hydroxy-polycarboxylic acid diester, a hydroxy-polycarboxylic acid diamide, a hydroxy-polycarboxylic acid imide, and a hydroxy-polycarboxylic acid ester amide. In one embodiment, the ashless antiwear agent is derived from a hydroxy-polycarboxylic acid imide.

[0095] Examples of suitable hydroxycarboxylic acids include citric acid, tartaric acid, lactic acid, glycolic acid, hydroxypropionic acid, hydroxyglutaric acid or mixtures thereof. In one embodiment, the ashless antiwear agent is derived from tartaric acid, citric acid, hydroxysuccinic acid, dihydroxymonoacids, monohydroxydiacids or mixtures thereof. In one embodiment, the ashless antiwear agent comprises a compound derived from tartaric acid or citric acid. In one embodiment, the ashless antiwear agent comprises a compound derived from tartaric acid.

[0096] US Patent Application 2005 / 198894 discloses suitable hydroxycarboxylic acid compounds and methods for their preparation.

[0097] Canadian Patent 1 183 125; U.S. Patent Publication Nos. 2006 / 0183647 and US-2006-0079413; U.S. Patent Application No. 60 / 867,402; and British Patent 2 105743A. all disclose examples of suitable tartaric acid derivatives. In one embodiment, the antiwear agent may include a tartrate or tartrimide as disclosed in International Publication WO 2006 / 044411 or Canadian Patent CA 1183 125. The tartrate or tartrimide may contain an alkyl ester group, wherein the total number of carbon atoms on the alkyl group is at least 8. In one embodiment, the antiwear agent may comprise a citrate.

[0098] The ashless, phosphorus-free antiwear agent may be present at 0.1 wt % to 5 wt %, 0.1 wt % to 3 wt %, or 0.2 wt % to 3 wt %, or 0.1 wt % to 1.5 wt %, or 0.5 wt % to 1.1 wt % of the lubricating composition.

[0099] In one embodiment, the present invention can also provide a lubricating composition, which also includes a metal dialkyl dithiophosphate. Typically, the metal dialkyl dithiophosphate can be zinc dialkyl dithiophosphate (ZDDP) or a mixture thereof. Zinc dialkyl dithiophosphates are known in the art. Zinc dialkyl dithiophosphates can be present in 0% to 3% by weight of the lubricating composition, or 0.1% to 1.5% by weight, or 0.5% to 0.9% by weight. In another embodiment, the amount of ZDDP present makes the total zinc contributing to the lubricant composition no more than 0.15% by weight of the composition, for example, zinc can be present in an amount of 0% to 0.15% by weight, or even less than 0.14% by weight, or even less than 0.11% by weight, or even less than 0.09% by weight, or even less than 0.07% by weight, or even less than 0.05% by weight, or even less than 0.03% by weight, and in another embodiment, in an amount of 0.01% to 0.14% by weight. In another embodiment, the lubricating composition is substantially free of zinc.

[0100] The zinc dialkyl dithiophosphates can be derived from primary alcohols, secondary alcohols, or combinations thereof. Typically, they are derived from primary and secondary alcohols containing 3 to 12 carbon atoms, and combinations thereof. In one embodiment, the zinc alkyl dithiophosphates include at least 25 mole % of secondary alkyl groups, or at least 40 mole % of secondary alkyl groups, or at least 75 mole % of secondary alkyl groups, or at least 90 mole % of secondary alkyl groups.

[0101] In one embodiment, the lubricating composition of the present invention further comprises a dispersant viscosity modifier. The dispersant viscosity modifier may be present at 0.05 wt % to 5 wt %, or 0.05 wt % to 4 wt %, or 0.05 wt % to 2 wt % of the lubricating composition.

[0102] Suitable dispersant viscosity modifiers include: functionalized polyolefins, for example, ethylene-propylene copolymers that have been functionalized with acylating agents such as maleic anhydride and amines; polymethacrylates functionalized with amines, or esterified styrene-maleic anhydride copolymers reacted with amines. A more detailed description of dispersant viscosity modifiers is disclosed in the following documents: International Publication WO2006 / 015130 or U.S. Patents 4,863,623; 6,107,257; 6,107,258; and 6,117,825. In one embodiment, the dispersant viscosity modifier may include those described in U.S. Patent 4,863,623 (see column 2, line 15 to column 3, line 52) or International Publication WO2006 / 015130 (see page 2, paragraph

[0008] ), and preparation examples are described in paragraphs

[0065] to

[0073] ).

[0103] Antioxidants provide and / or improve the antioxidant properties of organic compositions (including lubricant compositions containing organic components) by preventing or retarding oxidation and thermal decomposition. Suitable antioxidants may be catalytic or stoichiometric in activity and include any compound capable of inhibiting or decomposing free radicals (including peroxides).

[0104] The ashless antioxidant of the present invention may include one or more of an arylamine, a diarylamine, an alkylated arylamine, an alkylated diarylamine, a phenol, a hindered phenol, a sulfided olefin, or a mixture thereof. In one embodiment, the lubricating composition comprises an antioxidant or a mixture thereof. The antioxidant may be present in an amount of 0.05 wt % to 15 wt %, or 0.1 wt % to 10 wt %, or 0.5 wt % to 5 wt %, or 0.5 wt % to 3 wt %, or 0.3 wt % to 1.5 wt % of the lubricating composition.

[0105] The diarylamine or alkylated diarylamine can be phenyl-α-naphthylamine (PANA), alkylated diphenylamine, or alkylated phenylnaphthylamine or a mixture thereof. The alkylated diphenylamine can include dinonylated diphenylamine, nonyl diphenylamine, octyl diphenylamine, dioctylated diphenylamine, didecyl diphenylamine, decyl diphenylamine and a mixture thereof. In one embodiment, the diphenylamine can include nonyl diphenylamine, dinonyl diphenylamine, octyl diphenylamine, dioctyl diphenylamine or a mixture thereof. In one embodiment, the alkylated diphenylamine can include nonyl diphenylamine or dinonyl diphenylamine. The alkylated diarylamine can include octyl, dioctyl, nonyl, dinonyl, decyl or didecyl phenyl naphthylamine.

[0106] The diarylamine antioxidant of the present invention may be present at 0.1% to 10%, 0.35% to 5%, or even 0.5% to 2% by weight of the lubricating composition.

[0107] Phenolic antioxidants can be simple alkylphenols, hindered phenols or coupled phenolic compounds.

[0108] Hindered phenol antioxidants typically contain sec-butyl and / or tert-butyl groups as sterically hindered groups. The phenol group may typically be further substituted with a hydrocarbyl group (typically a straight or branched alkyl group) and / or a bridging group connected to a second aromatic group. Examples of suitable hindered phenol antioxidants include 2,6-di-tert-butylphenol, 4-methyl-2,6-di-tert-butylphenol, 4-ethyl-2,6-di-tert-butylphenol, 4-propyl-2,6-di-tert-butylphenol or 4-butyl-2,6-di-tert-butylphenol, 4-dodecyl-2,6-di-tert-butylphenol or butyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate. In one embodiment, the hindered phenol antioxidant may be an ester and may include, for example, Irganox® from Ciba. TM L-135.

[0109] The coupled phenols typically contain two alkylphenols coupled to an alkylene group to form a bisphenol compound. Examples of suitable coupled phenol compounds include 4,4'-methylenebis-(2,6-di-tert-butylphenol), 4-methyl-2,6-di-tert-butylphenol, 2,2'-bis-(6-tert-butyl-4-heptylphenol); 4,4'-bis(2,6-di-tert-butylphenol), 2,2'-methylenebis(4-methyl-6-tert-butylphenol) and 2,2'-methylenebis(4-ethyl-6-tert-butylphenol).

[0110] The phenol of the present invention also includes polyvalent aromatic compounds and their derivatives. Examples of suitable polyvalent aromatic compounds include esters and amides of gallic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 1,4-dihydroxy-2-naphthoic acid, 3,5-dihydroxynaphthoic acid, 3,7-dihydroxynaphthoic acid and mixtures thereof.

[0111] In one embodiment, the phenolic antioxidant comprises a hindered phenol. In another embodiment, the hindered phenol is derived from 2,6-di-tert-butylphenol.

[0112] In one embodiment, the lubricating composition of the present invention comprises a phenolic antioxidant in the range of 0.01 wt % to 5 wt %, or 0.1 wt % to 4 wt %, or 0.2 wt % to 3 wt %, or 0.5 wt % to 2 wt % of the lubricating composition.

[0113] Sulfurized olefins are well-known commercial materials and are substantially nitrogen-free, i.e., those sulfurized olefins that do not contain nitrogen functional groups are readily available. The properties of the olefin compounds that can be sulfurized are varied. They contain at least one olefin double bond, which is defined as a non-aromatic double bond; that is, a double bond connecting two aliphatic carbon atoms. These materials generally have a sulfur bond containing 1 to 10 sulfur atoms, such as 1 to 4 or 1 or 2 sulfur atoms. In one embodiment, the lubricating composition of the present invention comprises a sulfurized olefin in the range of 0.2 wt % to 2.5 wt %, or 0.5 wt % to 2.0 wt %, or 0.7 wt % to 1.5 wt %.

[0114] The ashless antioxidants of the present invention may be used alone or in combination. In one embodiment of the present invention, two or more different antioxidants are used in combination, so that each of at least two antioxidants is at least 0.1% by weight, and the combined amount of the ashless antioxidants is 0.5% to 5% by weight. In one embodiment, each ashless antioxidant may be present at least 0.25% to 3% by weight. In one embodiment, there may be 1.0% to 5.0% by weight of one or more ashless antioxidants, or 1.4% to 3.0% by weight of one or more antioxidants.

[0115] In one embodiment, the present invention provides a lubricating composition further comprising a molybdenum compound. The molybdenum compound may be selected from the group consisting of: molybdenum dialkyl dithiophosphates, molybdenum dithiocarbamates, amine salts of molybdenum compounds, and mixtures thereof. The molybdenum compound may provide 0 ppm to 1000 ppm, 5 ppm to 1000 ppm, 10 ppm to 750 ppm, 5 ppm to 300 ppm, or 20 ppm to 250 ppm of molybdenum to the lubricating composition.

[0116] In one embodiment, the present invention provides a lubricating composition further comprising a friction modifier. Examples of friction modifiers include long-chain fatty acid derivatives of amines, fatty esters or epoxides; fatty imidazolines, such as condensation products of carboxylic acids and polyalkylene polyamines; amine salts of alkyl phosphoric acids; fatty alkyl tartaric acid esters; fatty alkyl tartarimides; or fatty alkyl tartaramides. As used herein, the term fatty may refer to having a C8-22 straight chain alkyl group.

[0117] Friction modifiers may also encompass materials such as sulfurized fatty compounds and olefins, molybdenum dialkyl dithiophosphates, molybdenum dithiocarbamates, sunflower oil or monoesters of polyols, and aliphatic carboxylic acids.

[0118] In one embodiment, the friction modifier can be selected from the group consisting of: long chain fatty acid derivatives of amines, long chain fatty esters or long chain fatty epoxides; fatty imidazolines; amine salts of alkyl phosphoric acids; fatty alkyl tartaric acid esters; fatty alkyl tartarimides; and fatty alkyl tartaramides. The friction modifier can be present in 0.05 wt % to 6 wt %, or 0.05 wt % to 4 wt %, or 0.1 wt % to 2 wt % of the lubricating composition.

[0119] In one embodiment, the friction modifier may be a long chain fatty acid ester. In another embodiment, the long chain fatty acid ester may be a monoester or a diester or a mixture thereof, and in another embodiment, the long chain fatty acid ester may be a triglyceride.

[0120] Other performance additives, such as corrosion inhibitors include those described in paragraphs 5 to 8 of U.S. Patent Application US05 / 038319 published as WO2006 / 047486, octyl octanamide, condensation products of dodecenyl succinic acid or anhydride and fatty acids (such as oleic acid) with polyamines. In one embodiment, the corrosion inhibitors include (Registered trademark of The Dow Chemical Company) Corrosion Inhibitor. The corrosion inhibitor may be a homopolymer or a copolymer of propylene oxide. Corrosion inhibitors are described in more detail in a product brochure, Table No. 118-01453-0702 AMS, published by The Dow Chemical Company. The brochure is entitled "SYNALOX Lubricants, High-Performance Polyglycols for Demanding Applications."

[0121] The lubricating composition may also include a metal deactivator including a derivative of benzotriazole (typically tolyltriazole), a dithiothiadiazole derivative, 1,2,4-triazole, benzimidazole, 2-alkyldithiobenzimidazole or 2-alkyldithiobenzothiazole; a foam inhibitor including a copolymer of ethyl acrylate and 2-ethylhexyl acrylate, and a copolymer of ethyl acrylate and 2-ethylhexyl acrylate and vinyl acetate; a demulsifier including trialkyl phosphate, polyethylene glycol, polyethylene oxide, polypropylene oxide and (ethylene oxide-propylene oxide) polymer; and a pour point depressant including an ester of maleic anhydride-styrene, polymethacrylate, polyacrylate or polyacrylamide.

[0122] Pour point depressants that can be used in the composition of the present invention also include poly-alpha-olefins, maleic anhydride-styrene esters, poly(meth)acrylates, polyacrylates or polyacrylamides.

[0123] In various embodiments, the lubricating composition may have a composition as described in the following table:

[0124]

[0125] The present invention provides a surprising ability to provide antioxidant benefits including deposit control. The compositions of the present invention keep the oil in good working condition (e.g., pumpability, cleanliness, etc.), which provides benefits in terms of engine wear and life. The present invention provides a surprising ability to control damage to a running engine due to wear and deposit formation.

[0126] Industrial Applications

[0127] As described above, the present invention provides a method of lubricating an internal combustion engine, comprising supplying the lubricating composition as disclosed herein to the internal combustion engine. Generally speaking, lubricant is added to the lubrication system of the internal combustion engine, and then the lubricating composition is delivered to the key parts of the engine that need lubrication during its operation.

[0128] The lubricating composition described above may be utilized in an internal combustion engine.The engine component may have a surface of steel or aluminum (typically a surface of steel) and may also be coated, for example, with a diamond-like carbon (DLC) coating.

[0129] The aluminum surface may be composed of an aluminum alloy, which may be a eutectic or hypereutectic aluminum alloy such as those derived from aluminum silicate, aluminum oxide, or other ceramic materials. The aluminum surface may be present on a cylinder bore, cylinder block, or piston ring having an aluminum alloy or aluminum composite.

[0130] The internal combustion engine may be equipped with an emission control system or a turbocharger. Examples of emission control systems include a diesel particulate filter (DPF) or a system employing selective catalytic reduction (SCR).

[0131] The internal combustion engine of the present invention is different from a gas turbine. In an internal combustion engine, each combustion event converts a linear reciprocating force into a rotational torque through a rod and a crankshaft. In contrast, in a gas turbine (which may also be called a jet engine), the continuous combustion process continuously produces a rotational torque without translation, and may also produce thrust at the exhaust port. These differences in the operating conditions of gas turbines and internal combustion engines result in different operating environments and stresses.

[0132] The lubricant composition for an internal combustion engine may be suitable for any engine lubricant regardless of the sulfur, phosphorus or sulfated ash (ASTM D-874) content. The sulfur content of the engine oil lubricant may be 1 wt % or less, or 0.8 wt % or less, or 0.5 wt % or less, or 0.3 wt % or less, or 0.25 wt % or less. In one embodiment, the sulfur content may be in the range of 0.05 wt % to 0.5 wt %, or 0.1 wt % to 0.3 wt %, or even 0.15 wt % to 0.25 wt %. The phosphorus content may be from 0 wt % to 0.2 wt %, or even 0.2 wt % or less, or 0.12 wt % or less, or 0.1 wt % or less, or 0.09 wt % or less, or 0.08 wt % or less, or even 0.06 wt % or less, 0.05 wt % or less, or 0.03 wt % or less, or even 0.02 wt % or less or substantially free of added phosphorus. In one embodiment, the phosphorus content may be from 0 ppm to 1000 ppm, or from 100 ppm to 900 ppm, or from 200 ppm to 600 ppm. In another embodiment, the phosphorus content is less than 10 ppm by weight or even less than 5 ppm by weight. The total sulfated ash content may be 2 wt % or less, or 1.6 wt % or less, or 1.1 wt % or less, or 1 wt % or less, or 0.8 wt % or less, or 0.6 wt % or less, or 0.5 wt % or less. In one embodiment, the sulphated ash content may be from 0.05 wt % to 0.9 wt %, or from 0.1 wt % to 0.2 wt % or to 0.45 wt %.

[0133] In one embodiment, the lubricating composition can be an engine oil, wherein the lubricating composition can be characterized by having at least one of the following: (i) a sulfur content of 0.5 wt % or less, (ii) a phosphorus content of 0.1 wt % or less, (iii) a sulfated ash content of 1.5 wt % or less, or a combination thereof.

[0134] As described herein, the present invention provides a composition for lubricating an internal combustion engine, the composition comprising an oil of lubricating viscosity and a DMTD derivative, the DMTD derivative comprising a reaction product of 2,5-dimercapto-1,3,4-thiadiazole ("DMTD") and an α,β-unsaturated carbonyl compound, wherein the α,β-unsaturated carbonyl compound comprises an ester, amide or imide containing 4 to 24, or 4 to 18, or 4 to 12, or 6 to 8 carbon atoms. In the composition of this paragraph, the DMTD derivative is further reacted with a metal oxide, a metal hydroxide or a metal alkoxide to form a metal salt, wherein the metal is selected from zinc, titanium, molybdenum, antimony or a mixture thereof, or the DMTD derivative is further reacted with an amine to form an amine salt. In the composition of this paragraph, the DMTD derivative is present in an amount to deliver at least 0.05 wt % to 0.35 wt %, or 0.07 wt % to 0.3 wt %, or 0.08 wt % to 0.26 wt % sulfur to the lubricating composition. In addition, one or more metal-containing detergents are also included in the composition of this paragraph, wherein the metal-containing detergent is selected from magnesium, calcium, sodium and mixtures thereof, and wherein the detergent is selected from sulfonates, phenates, salicylates, salicylates or mixtures thereof. The composition of this paragraph contains a calcium detergent, and the amount of the calcium detergent is sufficient to deliver 500ppm to 3000ppm or 1000ppm to 2500ppm of calcium by weight to the composition. The composition of this paragraph may be substantially free of phosphorus or may be free of phosphorus. The composition of this paragraph may be zinc-free or substantially free of zinc, or may contain up to 0.15% by weight of zinc. The present invention provides a method for lubricating an internal combustion engine, the method comprising operating the engine with a lubricant composition, the lubricant composition comprising as described in this paragraph. The present invention provides a method for decomposing peroxides in a lubricating composition for lubricating an internal combustion engine, the method comprising supplying a lubricating composition as described in this paragraph to the internal combustion engine. In addition, the present invention includes the use of the lubricating composition as described in this paragraph for oxidation and deposit control in an internal combustion engine.

[0135] The present invention also provides a composition for lubricating an internal combustion engine, the composition comprising an oil of lubricating viscosity and a DMTD derivative, the DMTD derivative comprising a reaction product of 2,5-dimercapto-1,3,4-thiadiazole ("DMTD") and an α,β-unsaturated carbonyl compound, wherein the α,β-unsaturated carbonyl compound is an ester selected from the group consisting of maleate, acrylate, methacrylate, fumarate, crotonate, itaconate and mixtures thereof, wherein the ester contains 4 to 24, or 4 to 18, or 4 to 12, or 6 to 8 carbon atoms. In the composition of this paragraph, the DMTD derivative is further reacted with a metal oxide, a metal hydroxide or a metal alkoxide to form a metal salt, wherein the metal is selected from zinc, titanium, molybdenum, antimony or mixtures thereof, or the DMTD derivative is further reacted with an amine to form an amine salt. In the composition of this paragraph, the DMTD derivative is present in an amount of at least 0.05 wt % to 0.35 wt % or 0.07 wt % to 0.3 wt % or 0.08 wt % to 0.26 wt % sulfur delivered to the lubricating composition. In addition, one or more metal-containing detergents are also included in the composition of this paragraph, wherein the metal-containing detergent is selected from magnesium, calcium, sodium and their mixture, and wherein the detergent is selected from sulfonate, phenate, salicylate, salicylate or their mixture. The composition of this paragraph contains a calcium detergent, and the amount of the calcium detergent is enough to deliver 500ppm to 3000ppm or 1000ppm to 2500ppm of calcium by weight to the composition. The composition of this paragraph can be substantially phosphorus-free or can be phosphorus-free. The composition of this paragraph can be zinc-free or substantially zinc-free, or can contain zinc up to 0.15 wt %. The invention provides a method for lubricating an internal combustion engine, the method comprising operating the engine with a lubricant composition, the lubricant composition comprising as described in this paragraph. The present invention provides a method for decomposing peroxides in a lubricating composition for lubricating an internal combustion engine, the method comprising supplying the lubricating composition as described in this paragraph to the internal combustion engine. In addition, the present invention includes the use of the lubricating composition as described in this paragraph for oxidation and deposit control in an internal combustion engine.

[0136] The present invention also provides a composition for lubricating an internal combustion engine, the composition comprising an oil of lubricating viscosity and a DMTD derivative, the DMTD derivative comprising a reaction product of 2,5-dimercapto-1,3,4-thiadiazole ("DMTD") and an α,β-unsaturated carbonyl compound, wherein the α,β-unsaturated carbonyl compound comprises or consists of an alkyl acrylate (such as 2-ethylhexyl acrylate) or an alkyl methacrylate (such as lauryl methacrylate or 2-2-ethylhexyl methacrylate). In the composition of this paragraph, the DMTD derivative is further reacted with a metal oxide, a metal hydroxide or a metal alkoxide to form a metal salt, wherein the metal is selected from zinc, titanium, molybdenum, antimony or a mixture thereof, or the DMTD derivative is further reacted with an amine to form an amine salt. In the composition of this paragraph, the DMTD derivative is present in an amount to deliver at least 0.05 wt % to 0.35 wt %, or 0.07 wt % to 0.3 wt %, or 0.08 wt % to 0.26 wt % sulfur to the lubricating composition. In addition, one or more metal-containing detergents are also included in the composition of this paragraph, wherein the metal-containing detergent is selected from magnesium, calcium, sodium and mixtures thereof, and wherein the detergent is selected from sulfonates, phenates, salicylates, salicylates or mixtures thereof. The composition of this paragraph contains a calcium detergent, and the amount of the calcium detergent is sufficient to deliver 500ppm to 3000ppm or 1000ppm to 2500ppm of calcium by weight to the composition. The composition of this paragraph may be substantially free of phosphorus or may be free of phosphorus. The composition of this paragraph may be zinc-free or substantially free of zinc, or may contain up to 0.15% by weight of zinc. The present invention provides a method for lubricating an internal combustion engine, the method comprising operating the engine with a lubricant composition, the lubricant composition comprising as described in this paragraph. The present invention provides a method for decomposing peroxides in a lubricating composition for lubricating an internal combustion engine, the method comprising supplying a lubricating composition as described in this paragraph to the internal combustion engine. In addition, the present invention includes the use of the lubricating composition as described in this paragraph for oxidation and deposit control in an internal combustion engine.

[0137] The present invention also provides a composition for lubricating an internal combustion engine, the composition comprising an oil of lubricating viscosity and a DMTD derivative, the DMTD derivative comprising a reaction product of 2,5-dimercapto-1,3,4-thiadiazole ("DMTD") and an α,β-unsaturated carbonyl compound, wherein the α,β-unsaturated carbonyl compound comprises or consists of a dialkyl maleate (such as bis-(2-ethylhexyl) maleate). In the composition of this paragraph, the DMTD derivative is further reacted with a metal oxide, a metal hydroxide or a metal alkoxide to form a metal salt, wherein the metal is selected from zinc, titanium, molybdenum, antimony or a mixture thereof, or the DMTD derivative is further reacted with an amine to form an amine salt. In the composition of this paragraph, the DMTD derivative is present in an amount to deliver at least 0.05 wt % to 0.35 wt %, or 0.07 wt % to 0.3 wt %, or 0.08 wt % to 0.26 wt % sulfur to the lubricating composition. In addition, one or more metal-containing detergents are also included in the composition of this paragraph, wherein the metal-containing detergent is selected from magnesium, calcium, sodium and mixtures thereof, and wherein the detergent is selected from sulfonates, phenates, salicylates, salicylates or mixtures thereof. The composition of this paragraph contains a calcium detergent, and the amount of the calcium detergent is sufficient to deliver 500ppm to 3000ppm or 1000ppm to 2500ppm of calcium by weight to the composition. The composition of this paragraph may be substantially free of phosphorus or may be free of phosphorus. The composition of this paragraph may be zinc-free or substantially free of zinc, or may contain up to 0.15% by weight of zinc. The present invention provides a method for lubricating an internal combustion engine, the method comprising operating the engine with a lubricant composition, the lubricant composition comprising as described in this paragraph. The present invention provides a method for decomposing peroxides in a lubricating composition for lubricating an internal combustion engine, the method comprising supplying a lubricating composition as described in this paragraph to the internal combustion engine. In addition, the present invention includes the use of the lubricating composition as described in this paragraph for oxidation and deposit control in an internal combustion engine.

[0138] The present invention also provides a composition for lubricating an internal combustion engine, the composition comprising an oil of lubricating viscosity and a DMTD derivative, the DMTD derivative comprising a reaction product of 2,5-dimercapto-1,3,4-thiadiazole ("DMTD") and an α,β-unsaturated carbonyl compound, wherein the α,β-unsaturated carbonyl compound comprises or consists of a dialkyl itaconate (such as bis-(2,4-dimethylpentyl) itaconate). In the composition of this paragraph, the DMTD derivative is further reacted with a metal oxide, a metal hydroxide or a metal alkoxide to form a metal salt, wherein the metal is selected from zinc, titanium, molybdenum, antimony or a mixture thereof, or the DMTD derivative is further reacted with an amine to form an amine salt. In the composition of this paragraph, the DMTD derivative is present in an amount to deliver at least 0.05 wt % to 0.35 wt %, or 0.07 wt % to 0.3 wt %, or 0.08 wt % to 0.26 wt % sulfur to the lubricating composition. In addition, one or more metal-containing detergents are also included in the composition of this paragraph, wherein the metal-containing detergent is selected from magnesium, calcium, sodium and mixtures thereof, and wherein the detergent is selected from sulfonates, phenates, salicylates, salicylates or mixtures thereof. The composition of this paragraph contains a calcium detergent, and the amount of the calcium detergent is sufficient to deliver 500ppm to 3000ppm or 1000ppm to 2500ppm of calcium by weight to the composition. The composition of this paragraph may be substantially free of phosphorus or may be free of phosphorus. The composition of this paragraph may be zinc-free or substantially free of zinc, or may contain up to 0.15% by weight of zinc. The present invention provides a method for lubricating an internal combustion engine, the method comprising operating the engine with a lubricant composition, the lubricant composition comprising as described in this paragraph. The present invention provides a method for decomposing peroxides in a lubricating composition for lubricating an internal combustion engine, the method comprising supplying a lubricating composition as described in this paragraph to the internal combustion engine. In addition, the present invention includes the use of the lubricating composition as described in this paragraph for oxidation and deposit control in an internal combustion engine.

[0139] Example

[0140] The invention will be further illustrated by the following examples, which illustrate particularly advantageous embodiments.While the examples are provided to illustrate the invention, they are not intended to limit the invention.

[0141] Examples 1 to 5 are formed by the reaction of DMTD and an α,β-unsaturated carbonyl compound and have the following formula V:

[0142]

[0143] Generally, DMTD and solvent (ethyl acetate or toluene) are added to a reaction vessel. The unsaturated carbonyl compound is added to a reaction flask and the mixture is heated at an elevated temperature (reaction temperature in the range of 40° C. to 120° C.) for 2.5 to 30 hours. The solvent is removed in vacuo. For Examples 1 to 5, X=H, and n=1.

[0144] Table 1. Adducts formed by Michael addition of DMTD to the unsaturated carbonyl compounds listed below .

[0145] Unsaturated carbonyl compounds <![CDATA[R1]]> <![CDATA[R2]]> <![CDATA[R3]]> Example 1 Bis-(2-ethylhexyl) maleate <![CDATA[COOR3]]> H <![CDATA[2-EHL 1 ]]> Example 2 2-Ethylhexyl acrylate H H 2-EHL Example 3 2-Ethylhexyl Methacrylate H <![CDATA[CH3]]> 2-EHL Example 4 Bis(2,4-dimethylpentyl)itaconate H <![CDATA[CH2COOR3]]> <![CDATA[DMP 2 ]]> Example 5 Lauryl Methacrylate H <![CDATA[CH3]]>

[0146] 1 2-EHL = 2-ethylhexyl

[0147] 2 DMP = dimethylpentyl

[0148] Examples 6 to 7 are salts formed by further reacting Example 1 with a metal source. Examples 8 to 11 are salts formed by further reacting Example 2 with a metal source or an amine. The salification reaction is typically performed by adding Example 1 or Example 2 to a reaction flask and then adding the salifying agent listed in the table below. The reactants are heated at a reaction temperature between 40° C. and 150° C. for 1 to 6 hours. In some cases, the reactant mixture is placed under vacuum to remove volatile byproducts.

[0149] Table 2. Salt adducts

[0150] Unsaturated carbonyl compounds <![CDATA[R1]]> <![CDATA[R2]]> <![CDATA[R3]]> Salting agent Example 6 Bis-(2-ethylhexyl) maleate <![CDATA[COOR3]]> H 2-EHL ZnO Example 7 Bis-(2-ethylhexyl) maleate <![CDATA[COOR3]]> H 2-EHL <![CDATA[Ti(iOPr)4]]> Example 8 2-Ethylhexyl acrylate H H 2-EHL <![CDATA[TMEDA 3 ]]> Example 9 2-Ethylhexyl acrylate H H 2-EHL <![CDATA[TTZL 4 ]]> Example 10 2-Ethylhexyl acrylate H H 2-EHL <![CDATA[Ti(iOPr)4]]> Embodiment 11 2-Ethylhexyl acrylate H H 2-EHL <![CDATA[Sb2O3]]>

[0151] 3 TMEDA = Tetramethylethylenediamine

[0152] 4 TTZL = Tolyltriazole

[0153] According to the formulation listed in Table 3, the examples of Table 1 above were blended into fully formulated fluids.

[0154] Table 3. Fully formulated fluids containing components of the present invention

[0155]

[0156] The examples of Table 2 were blended according to the formulations in Table 4 into fully formulated fluids.

[0157] Table 4. Fully formulated fluids containing components of the present invention .

[0158] Fluid 8 Fluid 9 Fluid 10 Fluid 11 Fluid 12 Fluid 13 Succinimide dispersant 2.92 2.92 2.92 2.92 2.92 2.92 Borated succinimide dispersant 2.85 2.85 2.85 2.85 2.85 2.85 Alkoxylated phenol 2 2 2 2 2 2 Calcium Salicylate 1.12 1.12 1.12 1.12 1.12 1.12 Magnesium sulfonate detergent 0.29 0.29 0.29 0.29 0.29 0.29 Si-based defoamer 0.01 0.01 0.01 0.01 0.01 0.01 Phenolic antioxidants 1.5 1.5 1.5 1.5 1.5 1.5 Example 6 1.29 Example 7 1.24 Example 8 1.02 Example 9 1.11 Example 10 0.89 Embodiment 11 0.81 S%(ASTM D4951) 0.246 0.251 0.251 0.251 0.258 0.235

[0159] Every kind of fully prepared fluid listed in Table 3 and Table 4 is evaluated in the hydroperoxide decomposer (HPD) test according to the following procedure.In this test, 50g of every kind of fully prepared fluid is added to the 100ml three-necked flask equipped with a magnetic stirrer.Sample is heated to 140 ℃, 0.5ml tert-butyl hydroperoxide solution is added and stopwatch is started.After 2 minutes and 55 seconds, about 2ml reaction mixture sample is removed and stored in a vial.After 3 minutes, other 0.5ml tert-butyl hydroperoxide solution is added to the 100ml flask.After 5 minutes and 55 seconds, second 2ml sample is removed and stored in a vial.After 6 minutes, other 0.5ml tert-butyl hydroperoxide solution is added.After 9 minutes, 14 minutes and 19 minutes, about 2ml sample is removed and stored in a vial.Then each sample collected by iodine titration test is determined to determine the hydroperoxide number (i.e. the residual amount of peroxide present in each sample) of each sample.

[0160] For each sample collected, add 5ml titration solvent (3:2 acetic acid: chloroform). Cover the vial and swirl to stir the contents. Saturated potassium iodide solution (0.4ml) is added to each vial. The vial is capped and swirled again. The vials are then stored in a dark place and left overnight (16 hours) to allow iodine to be released from the solution. 5ml deionized water is added to each sample vial the next day. The vial is capped and swirled to mix. Starch indicator solution (3 to 4 drops) is added to the sample vial immediately before titration. A dark blue-purple color is produced. Each sample is titrated with 0.1M sodium thiosulfate solution until a noticeable color change occurs. Ensure that the color change is permanent by swirling for a moment. If the blue-purple color reappears, continue titration. Record the titration volume (ml). Hydroperoxide number (HPN) can be calculated by the following equation:

[0161] HPN = titration volume (ml) × molar concentration of titrant × 1000

[0162] Sample weight (g)

[0163] A lower HPN value indicates that the formulation is an effective hydroperoxide decomposer, while a higher HPN value indicates a formulation with a less effective hydroperoxide decomposer. The results are summarized in Tables 5 and 6.

[0164] Table 5. HPN results for Fluids 1 to 7.

[0165]

[0166]

[0167] *The figures reported are the average of five separate analyses.

[0168] Table 6. HPN results for fluids 8 to 13 .

[0169]

[0170] It is known that some of the above-mentioned substances may interact in the final formulation so that the components of the final formulation may be different from those initially added. The products thus formed, including the products formed by using the lubricant composition of the present invention in its intended use, may not be susceptible to easy description. However, all such modifications and reaction products are included within the scope of the present invention. The present invention includes lubricating compositions prepared by mixing the above-mentioned components.

[0171] Each of the above-mentioned documents is incorporated herein by reference together with the priority documents and all related applications (if any) that the application claims for its rights and interests. Unless otherwise specified in the examples or otherwise clearly indicated, all numerical values ​​of the amount of a substance, reaction conditions, molecular weight, number of carbon atoms, etc., specified in this specification should be understood to be modified by the word "about". Unless otherwise specified, each chemical or composition mentioned herein should be interpreted as a commercial grade material, which may contain isomers, by-products, derivatives and other such materials generally understood to be present in the commercial grade. However, unless otherwise specified, the amount of each chemical component does not include any solvent or diluent oil, which may be present in commercial materials. It should be understood that the upper and lower limits of the amount, range and ratio described herein can be independently combined. Similarly, the scope and amount of each element of the present invention can be used together with the scope or amount of any other element.

[0172] As used herein, the term "alkyl" refers to a group having a carbon atom directly connected to the rest of the molecule, wherein the group includes at least a carbon atom and a hydrogen atom. If the alkyl group contains more than one carbon atom, these carbons do not have to be connected to each other. For example, at least two carbons can be connected via a suitable element or group. In various embodiments, the term "alkyl" refers to a group having a carbon atom directly connected to the rest of the molecule, wherein the group is composed of carbon, hydrogen, and optionally one or more heteroatoms, provided that the heteroatom does not change the main hydrocarbon nature of the substituent. The heteroatom can connect at least two carbons in the alkyl group and optionally no more than two non-hydrocarbon substituents. Suitable heteroatoms will be apparent to those skilled in the art, and include, for example, sulfur, nitrogen, oxygen, phosphorus and silicon. When the alkyl group contains heteroatoms, optionally, no more than two heteroatoms will be present for every ten carbon atoms in the alkyl group. Suitable non-hydrocarbon substituents will also be apparent to those skilled in the art, and include, for example, halo, hydroxyl, alkoxy, sulfhydryl, alkylthiol, nitro, nitroso and sulfinyl.

[0173] Thus, examples of hydrocarbyl groups in the context of the present technology include:

[0174] (i) a hydrocarbon group selected from aliphatic (eg, alkyl or alkenyl), alicyclic (eg, cycloalkyl, cycloalkenyl, cycloalkadienyl) and aromatic groups;

[0175] (ii) a substituted hydrocarbon group selected from the hydrocarbon group defined in (i) substituted with not more than two non-hydrocarbon substituents and / or one or more hydrocarbon substituents selected from the group consisting of halo, hydroxy, alkoxy, mercapto, alkylmercapto, nitro, nitroso and sulfinyl;

[0176] (iii) a hydrocarbon group containing heteroatoms, selected from the hydrocarbon groups defined in (i) containing one or more heteroatoms in the ring or chain, provided that no more than two heteroatoms are present for every ten carbon atoms in the group, the heteroatoms being selected from sulfur, nitrogen, oxygen, phosphorus and silicon. The hydrocarbon group containing heteroatoms may be substituted with no more than two non-hydrocarbon substituents and / or one or more hydrocarbon substituents.

[0177] In some embodiments, the term "hydrocarbyl" refers to a group having a carbon atom directly attached to the remainder of the molecule, wherein the group consists of carbon atoms and hydrogen atoms.

[0178] As used herein, the transitional term "comprising," which is synonymous with "comprising," "containing," or "characterized by," is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. However, in each use of "comprising" herein, it is intended that the term also encompasses the phrases "consisting essentially of" and "consisting of" as alternative embodiments, wherein "consisting of" excludes any element or step not specified, and "consisting essentially of" allows for the inclusion of additional, unrecited elements or steps that do not materially affect the essential or basic and novel characteristics of the composition or method under consideration. When applied to an element of a claim, the expression "consisting of" or "consisting essentially of" is intended to limit all substances of the type represented by the element, notwithstanding the presence of "comprising" elsewhere in the claim. As used herein, "substantially free of" means that the amount of the substance under consideration is lower than the amount that would affect the fluid-related properties in a measurable manner. "Substantially free of" may also mean that the substance under consideration is not intentionally added to the composition, but does not exclude the presence of such materials as contaminants. "Substantially free" can also mean that the substance under consideration can be present in an amount below the detection limit of a standard test method now known or later developed by those skilled in the art. In some embodiments, "substantially free" can mean less than 10 ppm by weight or even less than 5 ppm by weight.

[0179] Although the present invention has been explained with respect to its preferred embodiment, it should be understood that various modifications thereof will become apparent to those skilled in the art upon reading this specification. Therefore, it should be understood that the invention disclosed herein is intended to cover these modifications falling within the scope of the appended claims.

Claims

1. A composition for lubricating an internal combustion engine, the composition comprising: oil of lubricating viscosity; and DMTD derivatives, the DMTD derivatives comprising the reaction product of 2,5-dimercapto-1,3,4-thiadiazole ("DMTD") and an α,β-unsaturated carbonyl compound.

2. The composition of claim 1, wherein the α,β-unsaturated carbonyl compound comprises an ester, an amide or an imide.

3. The composition according to claim 2, wherein the α,β-unsaturated carbonyl compound is an ester selected from the group consisting of maleate, acrylate, methacrylate, fumarate, crotonate, itaconate and mixtures thereof.

4. The composition of claim 3, wherein the α,β-unsaturated ester contains 4 to 24, or 4 to 18, or 4 to 12, or 6 to 8 carbon atoms.

5. The composition according to claim 3 or 4, wherein the α,β-unsaturated ester comprises or consists of an alkyl acrylate.

6. The composition of claim 5, wherein the alkyl acrylate comprises or consists of 2-ethylhexyl acrylate.

7. The composition according to any one of claims 3 to 5, wherein the α,β-unsaturated ester comprises or consists of an alkyl methacrylate.

8. The composition of claim 7, wherein the alkyl methacrylate comprises or consists of lauryl methacrylate.

9. The composition of claim 7, wherein the alkyl methacrylate comprises or consists of 2-ethylhexyl methacrylate.

10. The composition of claim 3 or 4, wherein the α,β-unsaturated ester comprises or consists of a dialkyl maleate.

11. The composition of claim 10, wherein the dialkyl maleate comprises or consists of bis-(2-ethylhexyl) maleate.

12. The composition of claim 3 or 4, wherein the α,β-unsaturated ester comprises or consists of a dialkyl itaconate.

13. The composition of claim 12, wherein the dialkyl itaconate comprises or consists of bis-(2,4-dimethylpentyl) itaconate.

14. The composition according to any preceding claim, wherein the DMTD derivative is further reacted with a metal oxide, metal hydroxide or metal alkoxide to form a metal salt.

15. The composition of claim 14, wherein the metal is selected from zinc, titanium, molybdenum, antimony or mixtures thereof.

16. The composition of any one of claims 1 to 14, wherein the DMTD derivative is substantially free or free of zinc.

17. The composition according to any one of claims 1 to 13, wherein the DMTD derivative is further reacted with an amine to form an amine salt.

18. The composition of claim 17, wherein the amine is selected from the group consisting of methylamine, ethylamine, n-propylamine, n-butylamine, n-hexylamine, n-octylamine, 2-ethylhexylamine, benzylamine, 2-phenylethylamine, coconut amine, oleylamine, tridecylamine, isopropylamine, sec-butylamine, tert-butylamine, tert-hexylamine, 1-methyl-1-amino-cyclohexane, tert-octylamine, tert-decylamine, tert-dodecylamine, tert-tetradecylamine, tert-hexadecylamine, tert-octadecylamine, tert-tetracosylamine and tert-octacosylamine, cyclopentylamine, cyclohexylamine and 1-phenylethylamine; dialkylamines such as dimethylamine, diethylamine, dipropylamine, diiso ... Propylamine, dibutylamine, dicyclohexylamine, di-(2-ethylhexyl)amine, dihexylamine, ethylbutylamine, N-ethylcyclohexylamine and N-methylcyclohexylamine; cycloalkylamines such as piperidine, N-ethylpiperidine, N,N"-dimethylpiperazine, morpholine, N-methylmorpholine, N-ethylmorpholine, N-methylpiperidine, pyrrolidine, N-methylpyrrolidine and N-ethylpyrrolidine; and trialkylamines such as tetramethylethylenediamine, trimethylamine, triethylamine, tripropylamine, triisopropylamine, tributylamine, trihexylamine, N,N-dimethylbenzylamine, dimethylethylamine, dimethylisopropylamine, dimethylbutylamine and N,N-dimethylcyclohexylamine.

19. A lubricating composition according to any preceding claim, wherein the DMTD derivative is substantially free of or free of alkali metals and / or alkaline earth metals.

20. The composition of any preceding claim, wherein the DMTD derivative is present in an amount to deliver at least 0.05 wt% to 0.35 wt%, or 0.07 wt% to 0.3 wt%, or 0.08 wt% to 0.26 wt% sulfur to the lubricating composition.

21. A composition according to any preceding claim, wherein the lubricating composition further comprises one or more metal-containing detergents.

22. The composition of claim 21, wherein the metal in the metal-containing detergent is selected from the group consisting of magnesium, calcium, sodium and mixtures thereof.

23. The composition according to claim 21 or 22, wherein the detergent of the metal-containing detergent is selected from sulfonates, phenates, salicylates, salicylates or mixtures thereof.

24. A composition according to any one of claims 21 to 23, wherein the metal-containing detergent comprises a calcium detergent, and wherein the calcium detergent is present in an amount sufficient to deliver 500 ppm to 3000 ppm or 1000 ppm to 2500 ppm by weight calcium to the composition.

25. The composition of any one of claims 21 to 24, wherein the metal-containing detergent comprises a magnesium detergent, and wherein the magnesium detergent is present in an amount to deliver up to 500 ppm magnesium to the composition.

26. A composition according to any preceding claim further comprising a molybdenum compound.

27. A composition according to any preceding claim, wherein the composition comprises phosphorus in an amount of 0.2 wt % or less, or 0.12 wt % or less, or 0.1 wt % or less, or 0.09 wt % or less, or 0.08 wt % or less, or 0.06 wt % or less, 0.05 wt % or less, or 0.03 wt % or less, or even 0.02 wt % or less.

28. A composition according to any preceding claim, wherein the composition is substantially free or free of phosphorus.

29. The composition of any one of claims 1 to 27, further comprising a metal alkylthiophosphate.

30. The composition of claim 29, wherein the metal alkylthiophosphate comprises a zinc dialkyldithiophosphate.

31. The composition of claim 30, wherein the zinc dialkyl dithiophosphate is present in an amount sufficient to provide 0.02% to 0.2% zinc by weight to the composition.

32. The composition of any one of claims 1 to 31, wherein the composition contains 0.015 wt% or less zinc.

33. A composition according to any one of claims 1 to 32, wherein the composition contains zinc in an amount of less than 0.14 wt.%, or even less than 0.11 wt.%, or even less than 0.09 wt.%, or even less than 0.07 wt.%, or even less than 0.05 wt.%, or even less than 0.03 wt.%, or in an amount between 0.01 wt.% and 0.14 wt.%.

34. A composition according to any one of claims 1 to 29, wherein the composition is substantially free of zinc.

35. A composition according to any preceding claim, wherein the composition contains from 0.1 wt% to 0.4 wt% sulphurised olefin.

36. The composition of any one of claims 1 to 34, wherein the lubricating composition is substantially free of or free of sulphurised olefin additives.

37. A composition according to any one of claims 1 to 36, wherein the composition has a total sulfated ash content of 2 wt% or less, or 1.6 wt% or less, or 1.1 wt% or less, or 1 wt% or less, or 0.8 wt% or less, or 0.6 wt% or less, or 0.5 wt% or less, or from 0.05 wt% to 0.9 wt%, or from 0.1 wt% to 0.2 wt%, or to 0.45 wt%.

38. A method of lubricating an internal combustion engine, the method comprising: Operating the engine having the lubricant composition according to claims 1 to 37.

39. A method for decomposing peroxides in a lubricating composition for lubricating an internal combustion engine, the method comprising: The internal combustion engine is supplied with a lubricating composition according to claims 1 to 37.

40. Use of a lubricating composition according to claims 1 to 37 for oxidation and deposit control in an internal combustion engine.

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