ES2648996T3 - Viscosity control method - Google Patents

Abstract

Method for lubricating an internal combustion engine comprising a crankcase and at least one of a gear and a wet clutch, said method comprising supplying said crankcase and at least one of said wet gear and clutch a lubricating composition comprising: (a ) a lubricant viscosity oil; and (b) a viscosity modifier with a number average molecular weight of 1000 to 75,000, in which the viscosity modifier is a poly (meth) acrylate, in which the viscosity modifier has a stability index shear (SSI) as determined by CEC standard L-45-A-99 of 22 or less, in which the lubricant composition has an SAE viscosity grade of XW-Y, in which X is 0 to 20 and Y is from 20 to 50; and wherein the lubricant composition has a phosphorus content of a metal hydrocarbyl dithiophosphate of 0.12% by weight or less, in which the internal combustion engine is a 4-stroke motorcycle engine.

Description

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DESCRIPTION

Method of viscosity control Field of the invention

The present invention relates to a method of controlling the viscosity by lubrication of an internal combustion engine comprising at least one of a crankcase, a gear, and a wet clutch with a lubricating composition.

Background of the invention

It is well known that lubricating oils contain a number of additives used to protect the engine from wear and provide viscosity control. Common additives for motor lubricating oils include dialkyl dithiophosphate (ZDDP) an antiwear additive. It is believed that ZDDP antiwear additives protect the motor by forming a protective film on the metal surfaces. Viscosity modifiers with an average molecular weight in number greater than 100,000 in carter applications are known as viscosity modifiers because they help control high temperature viscometna in multigrade lubricants. Viscosity modifiers are known in various application documents, for example, US Patent No. 5,112,509.

Current and future government laws regulating the exhaust emissions of internal combustion engines that contain exhaust gas treatment devices require a reduction in the phosphorus and metal content of the engine oils used in these engines. This reduction in the phosphorus and metal content of engine oils is being implemented because it is thought that they may adversely affect the performance of exhaust gas treatment devices.

However, any reduction in the performance of catalytic converters caused by phosphorus poisoning tends to result in an increase in the amount of greenhouse gases such as metric oxide and / or ash formation. In addition, reducing the amount of ZDDP will increase the amount of wear on an engine case.

In an internal combustion engine with a wet clutch (for example, a 4-stroke motorcycle engine), the legislation regulating exhaust emissions affects / restricts the amount of emissions. However, since the internal combustion engine has a common oil tank, the oil must be suitable for a gearbox and gear application, a transmission system or a clutch mechanism that all have higher operating conditions, giving as result an environment of intense wear. Therefore, the removal of chemical wear, such as a phosphorus-containing compound, will tend to increase the amount of wear on the gear, transmission or clutch. If a conventional carter viscosity modifier (with an average molecular weight in number of 100,000 or more) is used in combination with reduced amounts of wear-resistant chemistry, it is believed that the surface of the film decomposed due to the shear of the modifier of the viscosity will lead to increased wear. It is believed that the decomposed surface film is due to a reduction in the high temperature viscosity of a lubricating oil proportional to the shear rate of the viscosity modifier.

It is advantageous to have a viscosity control method for an internal combustion engine with a wet clutch capable of imparting at least one of wear control, acceptable fuel economy, viscometna at acceptable high temperature and increased oil service drains lubricant. The present invention provides a viscosity control method for said internal combustion engine and is capable of imparting at least one of wear control, acceptable fuel economy, viscometna at acceptable high temperature and increased lubricating oil service drains .

Summary of the invention

The present invention provides a method of lubricating an internal combustion engine comprising a crankcase and at least one of a gear and a wet clutch, said method comprising providing said crankcase and at least one of said wet gear and clutch a composition lubricant comprising:

(a) an oil of lubricant viscosity; Y

(b) a viscosity modifier with an average molecular weight in number from about 1000 to about 75,000, in which the viscosity modifier is a poly (meth) acrylate, in which the viscosity modifier has an index of shear stability (SSI) as determined by CEC standard L-45-A-99 of 22 or less,

wherein the lubricant composition has an SAE viscosity grade of XW-Y, in which X is from 0 to about 20 and Y is from about 20 to about 50; and in which the lubricating composition

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It has a phosphorus content of a metal hydrocarbyl dithiophosphate of 0.12% by weight or less, in which the internal combustion engine is a 4-stroke motorcycle engine.

Detailed description of the invention

The present invention provides a method of lubricating an internal combustion engine comprising a crankcase and at least one of a gear and a wet clutch, said method comprising providing said crankcase and at least one of the wet gear and clutch a composition. lubricant comprising: (a) an oil of lubricant viscosity; and (b) a viscosity modifier with a number average molecular weight of 1000 to 75,000, in which the lubricating composition has an SAE viscosity grade of XW-Y, in which X is 0 to 20 and Y is from 20 to 50; and wherein the lubricating composition has a phosphorus content of a metal hydrocarbyl dithiophosphate of 0.12% by weight or less

Internal combustion engine

The internal combustion engine of the invention generally comprises a carter, a gear and a wet clutch. Optionally, the internal combustion engine further comprises a manual or automatic transmission. In one embodiment the gear is from a gearbox.

As used herein, the person skilled in the art knows that the term "wet clutch" means that which contains a clutch plate or plates that are cleaned or sprayed with a lubricant, for example, those of the transmission, and the Lube oil is between the plate or plates.

In one embodiment, the internal combustion engine has a common oil tank that supplies the same lubricant composition to the crankcase and at least one of a gear and a wet clutch. In certain embodiments, the lubricant composition is supplied to the crankcase and gear (or the multiplicity of gears), or to the crankcase and the wet clutch, or to the crankcase and both the gear (or gears) and the wet clutch.

The internal combustion engine is suitable for motorcycles, for example, motorcycles with a 4-stroke internal combustion engine.

Lubricant viscosity oil

The lubricant composition includes natural or synthetic oils of lubricating viscosity; oil obtained from hydrocracking, hydrogenation or hydro-finishing; and unrefined, refined or doubly refined oils and mixtures thereof.

Natural oils include animal oils, vegetable oils, mineral oils and mixtures thereof.

Synthetic oils include hydrocarbon oils, silicon-based oils, and liquid esters of phosphorus-containing acids. Synthetic oils can be produced by the Fischer-Tropsch synthetic gas-to-liquid method as well as other liquid-gas oils. In one embodiment, the polymer composition of the present invention is useful when used in a liquid gas oil. Often, hydrocarbons or Fischer-Tropsch waxes can be hydroisomerized.

In one embodiment, the base oil is a polyalphaolefin (PAO) including a PAO-2, PAO-4, PAO-5, PAO-6, PAO-7 or PAO-8 (the numerical value refers to the kinematic viscosity a 100 ° C). In one embodiment, the polyalphaolefin is prepared from dodecene and in another embodiment from decene. Generally, the polyalphaolefin suitable as an oil of lubricating viscosity has a viscosity lower than that of a PAO-20 or PAO-30 oil, the reason being that a polyalphaolefin with a viscosity greater than a PAO-30 is generally too viscous for the effective lubrication of an internal combustion engine.

Lubricating viscosity oils can also be defined as specified in the Base Oil Interchangeability Guidelines of the American Petroleum Institute (API). In one embodiment, the lubricating viscosity oil comprises an API Group I, II, III, IV, V, VI oil or mixtures thereof, and in another embodiment an API Group II, III, IV oil or mixtures thereof. In another embodiment, the lubricating viscosity oil is a Group III or IV base oil and in another embodiment a Group IV base oil. If the lubricating viscosity oil is an API Group II, III, IV, V or VI oil, there may be up to 40% by weight and in another embodiment up to a maximum of 5% by weight of the lubricating oil of an oil of the API group I present.

In one embodiment, the lubricant composition has an SAE viscosity grade of XW-Y, in which X is from 0 to 20 and Y is from 20 to 50.

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In an embodiment X, it is selected from 0, 5, 10, 15 or 20.

In one embodiment Y is selected from 20, 25, 30, 35, 40, 45 or 50.

In one embodiment, the oil of lubricating viscosity is present from 2% by weight to 99.5% by weight of the lubricating composition, in another embodiment from 29% by weight to 98.25% by weight of the composition. lubricant and in another embodiment from 40% by weight to 97% by weight of the lubricant composition. Some examples of suitable amounts of an oil of lubricating viscosity include 55% by weight, 60% by weight, 65% by weight, 70% by weight, 75% by weight or 80% by weight.

Viscosity modifier

The viscosity modifier of the invention includes at least one poly (meth) acrylate.

In one embodiment, the viscosity modifier is present from 0.5% by weight to 95% by weight, in another embodiment from 0.75% by weight to 70% by weight and in another embodiment from 1 % by weight to 40% by weight of the lubricant composition. Some examples of an adequate amount of viscosity modifier include 8% by weight, 10% by weight, 12% by weight, 14% by weight, 16% by weight, 18% by weight, 20% by weight, 22% by weight, 24% by weight, 30% by weight, 35% by weight, or 55% by weight.

Viscosity modifiers (which can also be dispersant viscosity modifiers, as described further below) are known in the art and are commercially available from a variety of companies, including The Lubrizol Corporation, Degussa AG and Rohmax GmbH .

The viscosity modifier has a shear stability index (SSI) as determined by CEC standard L-45-A-99 of 22 or less, 20 or less or 18 or less. In one embodiment, the viscosity SSI is 2 or more or 4 or more. Some examples of suitable SSI intervals include 2 to 22 or 4 to 18.

The viscosity modifier has an average molecular weight in number of 1000 to 75,000, in another embodiment of 2000 to 60,000, in another embodiment of 6000 to 50,000 and in another embodiment of 8000 to 40,000. In one embodiment the viscosity modifier has an average molecular weight in numbers of 1000 to 20,000 and in another embodiment of 25,000 to 40,000. In one embodiment, the dispersant viscosity modifier has an average molecular weight in number that is the same as the ranges given for the viscosity modifier.

Poly (meth) acrylates

The viscosity modifier is a poly (meth) acrylate, preferably with a number average molecular weight of 10,000 to 35,000, 12,000 to 20,000 or 25,000 to 35,000.

In one embodiment, the viscosity modifier of poly (meth) acrylate includes copolymers of (i) a methacrylic acid ester containing from 9 to 30 carbons in the ester group, (ii) a methacrylic acid ester containing from 7 at 12 carbons in the ester group in which the ester group contains two substituents (C1-4 alkyl) and optionally (iii) at least one monomer selected from the group consisting of a methacrylic acid ester containing from 2 to 8 atoms of carbon in the ester group and which are different from the esters of methacrylic acid used in sections (i) and (ii) above. A more detailed description of polymethacrylate viscosity modifiers can be found in US Patent No. 6,124,249.

In one embodiment, the viscosity modifier is a functionalized poly (meth) acrylate. The poly (meth) acrylate is functionalized with a nitrogen-containing monomer thus forming a dispersing viscosity modifier. In one embodiment, the nitrogen-containing monomer is incorporated into the poly (meth) acrylate through conventional copolymerization techniques. The nitrogen-containing monomer includes a vinyl substituted heterocyclic nitrogen monomer, a dialkylaminoalkyl (meth) acrylate monomer, a dialkylaminoalkyl (meth) acrylamide monomer, a tertiary (meth) acrylamide monomer and mixtures thereof. The alkyl groups may contain from 1 to 8, or from 1 to 3 carbon atoms. In one embodiment, the dispersant viscosity modifier is a poly (meth) acrylate.

The nitrogen-containing monomers useful include vinyl pyridine, imidazole N-vinyl, N-vinyl pyrrolidinone, and N-vinyl caprolactam, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, dimetilaminobutilacrilamida dimethylamine propyl methacrylate, dimethylaminopropylacrylamide, dimethylaminopropylmethacrylamide, dimethylaminoethylacrylamide, tert-butylacrylamide or mixtures thereof.

The polymeric dispersant viscosity modifier of poly (meth) acrylate includes a copolymer obtained from a (meth) acrylate monomer containing an alkyl group with 1 to 30 carbon atoms, in another embodiment of 1 to 26 carbon atoms and in another embodiment of 1 to 20 carbon atoms. The alkyl group includes mixtures obtained from an alcohol containing from 1 to 4 carbon atoms, from 8 to 10 carbon atoms, from 12 to 14 carbon atoms, from 12 to 15 carbon atoms, from 16 to 18 atoms carbon or 16 to 20 carbon atoms.

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Some examples of commercially available alcohol mixtures include the following products marketed under the trade names of Dobanol ™ 25, Neodol ™ 25, Lial ™ 125, and Alchem ™ 125. In one embodiment, alcohol is an individual alcohol, i.e. , is not a mixture.

The monomer of (meth) acrylate includes those obtained from natural or synthetic sources. When obtained from synthetic sources, the (meth) acrylate monomer can be prepared using known processes of direct esterification and / or transesterification.

In one embodiment, the polymeric dispersant viscosity modifier of poly (meth) acrylate is obtained from a monomer of (meth) methyl acrylate and at least one monomer of (meth) acrylate which includes an alkyl group with 8 to 20 carbon atoms, in another embodiment of 10 to 18 carbon atoms and in another embodiment of 12 to 15 carbon atoms. The methyl (meth) acrylate monomer is in the range of 1% by weight or more of the poly (meth) acrylate, in another embodiment in the range of 8% by weight or more of the poly (meth) acrylate and in another embodiment in the range of 10% by weight or more of the poly (meth) acrylate. The upper limits of the amount of methyl (meth) acrylate include 40% by weight of the poly (meth) acrylate, in another embodiment 30% by weight of the poly (meth) acrylate and in another embodiment 20% by weight of the poly (meth) acrylate.

Metal hydrocarbyl dithiophosphate

In one embodiment of the invention, the composition also contains a metal hydrocarbyl dithiophosphate. The amount of the metal hydrocarbyl dithiophosphate present is sufficient to provide a phosphorus content in the lubricating composition of said metal hydrocarbyl dithiophosphate of 0.12% by weight or less.

In one embodiment, the phosphorus content in the lubricating composition of a metal hydrocarbyl dithiophosphate is less than 0.1% by weight, in another embodiment less than 0.085% by weight, in another embodiment less than 0.06% by weight or less. In one embodiment, the lower limit of phosphorus content in the lubricating composition of a metal hydrocarbyl dithiophosphate is 0 ppm or greater, in another embodiment 50 ppm or greater, in another embodiment 125 ppm or greater and in another embodiment 200 ppm or greater. . Some examples of suitable ranges include 50 ppm to 0.1% by weight or 125 ppm to 0.085% by weight.

Some examples of a metal hydrocarbyl dithiophosphate include zinc dihydrocarbyl dithiophosphates (often referred to as ZDDP, ZDP or ZDTP). In one embodiment, the number of carbon atoms of each hydrocarbyl group is from 2 to 30, from 3 to 14 or from 4 to 10.

Some examples of suitable zinc hydrocarbyl dithiophosphate compounds may include those with an octyl, 2-ethylhexyl, methylpentyl-isopropyl, 2-ethylhexyl-isopropyl, pentyl isobutyl hydrocarbyl group or mixtures thereof.

Additional performance additives

In one embodiment of the invention, the composition optionally includes at least one additive of additional yield. The additional performance additive includes at least one of metal deactivators, detergents, dispersants, extreme pressure agents, antiwear agents, antioxidants, corrosion inhibitors, foam inhibitors, demulsifiers, pour point decreasers, friction modifiers, agents seal swelling and mixtures thereof. In one embodiment, the additional performance additives can be used alone or in combination.

In one embodiment, the total combined amount of the other performance additive compounds present ranges from 0% by weight to 30% by weight, in another embodiment from 1% by weight to 25% by weight and in another embodiment of 2% by weight to 20% by weight or 3% by weight to 10% by weight of the lubricant composition. Although one or more of the other performance additives may be present, it is common for the other additional performance additives to be present in different relative amounts between sr

If the present invention is in the form of a concentrate (which can be combined with additional oil to form, totally or partially, a finished lubricant), the proportion of the various additives with respect to the oil of lubricant viscosity and / or with respect to the Diluent oil includes ranges from 80:20 to 10:90 by weight.

Friction modifiers include fatty amines, esters such as borated glycerol esters, fatty phosphites, fatty acid amides, fatty epoxides, borated fatty epoxides, alkoxylated fatty amines, boiled alkoxylated fatty amines, fatty acid metal salts, fatty imidazolines, condensation products of carboxylic and polyalkylene polyamines, amine salts of alkyl phosphoric acids, molybdenum dithiocarbamate or mixtures thereof. Antioxidants include sulfated olefins, hindered phenols, diphenylamines. Detergents include basic, neutral or overbasic, Newtonian or non-Newtonian, alkali metal, alkaline earth metal and transitional salts with one or more of a phenate, a sulphided phenate, a sulphonate, a carboxylic acid, a phosphoric acid, a mono acid and / or dithiophosphoric, a saligenin, an alkylsalicylate, a salixarato or mixtures thereof. Dispersants include N-substituted succinimide with chain alkenyl

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long as well as later treated versions of it. Dispersants with subsequent treatment include those treated in addition to reaction with materials such as urea, boron, thiourea, dimercaptothiadiazoles, carbon disulfide, aldehydes, ketones, carboxylic acids, succinic anhydrides substituted with hydrocarbons, nitriles, epoxides and phosphorus compounds.

Anti-wear agents that include compounds such as metal thiophosphates, especially zinc dialkyldithiophosphates, may also be used in the composition of the invention; esters of phosphoric acid or salts thereof; phosphites; and carboxylic esters, ethers, and phosphorus-containing amides; Anti-scratch agents include sulphides and organic polysulfides, such as benzyl disulfide, bis- (chlorobenzyl) disulfide, dibutyl tetrasulfide, di tert-butyl polysulfide, di tert-butyl sulfide, sulphided Diels-Alder adducts or alkyl sulfenyl N'N-dialkyl dithiocarbamates. Extreme pressure agents (EP) include chlorinated wax, sulphides and organic polysulphides, such as benzyl disulfide, bis- (chlorobenzyl) disulfide, dibutyl tetrasulfide, sulphurous oleic acid methyl ester, sulfurized alkylphenol, sulphide dipentene, terpene sulphide, and sulphided Diels-Alder adducts; phosphosulfurized hydrocarbons, metal thiocarbamates, such as zinc dioctyldithiocarbamate and diacium barium heptylphenol.

Additional performance additives such as corrosion inhibitors including octylamine octanoate, acid condensation products or dodecenyl succinic anhydride and a fatty acid such as oleic acid with a polyamine may also be used in the composition of the invention; metal deactivators that include benzotriazole derivatives, thiadiazoles such as dimercaptothiadiazole and its derivatives, 1,2,4-triazoles, benzimidazoles, 2-alkyldithiobenzimidazoles or 2-alkyldithiobenzothiazoles; foam inhibitors including copolymers of ethyl acrylate and 2-ethylhexyl acrylate and optionally vinyl acetate; demulsifiers that include polyethylene glycols, polyethylene oxides, polypropylene oxides and polymers of (ethylene oxide-propylene oxide); pour point decreasers including esters of maleic anhydride styrene, polymethacrylates, polyacrylates or polyacrylamides; and seal swelling agents that include Exxon Necton-37 ™ (FN 1380) and Exxon Mineral Seal Oil (FN 3200).

The following examples provide an illustration of the invention. These examples are not exhaustive and are not intended to limit the scope of the invention.

Examples

Example 1 and Reference Examples 1-2

The lubricant compositions are prepared by mixing the additives shown in Table 1 in a 10W-40 lubricant. The lubricating compositions have a phosphorus content in the lubricating composition of a metal hydrocarbyl dithiophosphate of less than 0.12% by weight. The compositions prepared are:

Table 1

 Example

 Type of polymer Average molecular weight in number

 REF1

 Olefin copolymer available in the market More than 100,000

 REF2

 Commercially available olefin copolymer 84,000

 EJ1

 15,000 polymethacrylate

Viscosity test

A viscosity test is carried out to determine the shear stability index (SSI) using (i) a KRL Kit at 80 ° C for 20 hours and the methodology of the CEC standard L-45-A-99; and (ii) separately, an Orbahn ™ Equipment and the methodology of the CEC-14-A-93_30 standard. In general, better results are obtained for examples with lower percentage reductions in viscosity. In addition, acceptable results are obtained when the percentage loss in viscosity is 12% or less. The results obtained are shown in Table 2.

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Table 2

 Example

   SOT / EOT ___Equipment% loss KRL SSI / SSI (Orbahn)

 REF1

 O or> 14.96 7.94 46.93 76 25

 KV40

 98.2 48.50 50.61 - -

 REF2

 0 0> 11.86 10.30 13.15 26 0

 KV40

 77.39 65.52 15.34 - -

 EJ1

 0 0> 12.72 11.68 8.18 14 0

 KV40

 83.60 75.35 9.87 - -

Footnote to Table 2, SOT is defined as the start of the test; and EOT is defined as the end of the test and "-" represents unmeasured values.

The results indicate that the presence of the viscosity modifier with a number average molecular weight of 1000 to 75,000 has an acceptable shear stability and is suitable for viscosity control in an internal combustion engine comprising a carter and at least one of a gear and a wet clutch.

In addition, the viscosity modifier is capable of imparting at least one of wear control, acceptable fuel economy, acceptable high temperature viscometna and increased lubricating oil service drains. In addition, the results indicate that a polymer with a low shear stability index of 26 and an average molecular weight in number of more than 75,000 provides poor viscosity control performance.

In the present specification, the terms "hydrocarbyl substituent" or "hydrocarbyl group", as used herein, are used in their usual sense, which is well known to those skilled in the art.

Specifically, it refers to a group composed mainly of carbon and hydrogen atoms and attached to the rest of the molecule through a carbon atom and that does not exclude the presence of other atoms or groups in an insufficient proportion to limit the molecule to have a character mainly of hydrocarbon. In general, no more than two, in one aspect no more than one, substituents that are not hydrocarbon for every ten carbon atoms in the hydrocarbyl group will be present. Generally, there will be no substituent that is not hydrocarbon in the hydrocarbyl group. A more detailed definition of the terms "hydrocarbyl substituent" or "hydrocarbyl group" is provided in US Patent No. 6,583,092.

As used herein, the term poly (meth) acrylate, and other generic terms with (meth) acryl, means polymethacrylate, polyacrylate or other acryl or methacryl moieties.

Unless otherwise indicated, each chemical compound or composition referred to herein should be construed to be a commercial grade material that may contain isomers, by-products, derivatives, and other materials such as Normally understands that they are present in commercial quality. It is to be understood that the upper and lower amounts, the intervals, and the limits of the proportions set forth herein can be combined independently. Similarly, the intervals and quantities for each element of the invention can be used together with intervals or quantities for any of the other elements.

Claims (11)

5 10 fifteen twenty 25 30 35 40 1. Method for lubricating an internal combustion engine comprising a carter and at least one of a gear and a wet clutch, said method comprising supplying said carter and at least one of said gear and wet clutch a lubricating composition comprising: (a) an oil of lubricant viscosity; Y (b) a viscosity modifier with a number average molecular weight of 1000 to 75,000, in which the viscosity modifier is a poly (meth) acrylate, in which the viscosity modifier has a stability index of shear (SSI) as determined by CEC standard L-45-A-99 of 22 or less, wherein the lubricant composition has an SAE viscosity grade of XW-Y, in which X is from 0 to 20 and Y is from 20 to 50; and wherein the lubricant composition has a phosphorus content of a metal hydrocarbyl dithiophosphate of 0.12% by weight or less, in which the internal combustion engine is a 4-stroke motorcycle engine. 2. The method of claim 1, wherein the internal combustion engine has a common oil reservoir that supplies the same lubricant composition to the crankcase and at least one of a wet gear and clutch. 3. The method of claim 1, wherein the lubricant composition is supplied to the crankcase and to the gear or multiplicity of gears. 4. The method of claim 1, wherein the lubricant composition is supplied to the carter and the wet clutch. 5. The method of claim 1, wherein the lubricant composition is supplied to the crankcase and to both the gear (or gears) and the wet clutch. 6. The method of claim 1, wherein the viscosity modifier has a number average molecular weight of 2000 to 60,000, or 8000 to 40,000. 7. The method of claim 1, wherein the viscosity modifier has a number average molecular weight of 1000 to 20,000, or 25,000 to 40,000. 8. The method of claim 1, wherein the viscosity modifier is a functionalized poly (meth) acrylate. 9. The method of claim 8, wherein the poly (meth) acrylate is functionalized with a nitrogen-containing monomer. 10. The method of claim 1, wherein the viscosity modifier is present in an amount of 0.5% by weight to 95% by weight, or from 1% by weight to 40% by weight of the lubricant composition. 11. The method of claim 1, wherein the viscosity modifier has a shear stability index (SSI) as determined by CEC standard L-45-A-99 from 4 to 18.