JP4718159B2 - Engine oil composition - Google Patents

Description

  The present invention relates to an engine oil composition for an internal combustion engine. More particularly, the present invention relates to an engine oil composition that has excellent oxidation stability and does not cause an increase in oil viscosity due to deterioration.

  What is required of automobile engine oil is that, in addition to the function of lubricating the inside of the engine and maintaining cleanliness, engine oil that does not poison exhaust gas catalysts and has fuel saving functions are required due to recent environmental problems. It has been. Among these newly demanded functions, the fuel saving function includes, for example, a method of reducing the viscosity of engine oil to reduce the viscosity resistance, a method of reducing the friction coefficient during lubrication by blending organic molybdenum, etc. As a result, energy loss inside the engine has been reduced.

  The exhaust gas generated by combustion in the engine contains nitrogen oxides (NOx), sulfur oxides (SOx), etc., and these harmful substances cause environmental pollution, natural destruction, adverse effects on the human body, etc. It is known. Therefore, exhaust gas catalysts have been improved, but it is known that phosphorus and sulfur components contained in engine oil poison the exhaust gas catalyst, reducing phosphorus and sulfur components in engine oil. It has become necessary.

  Specifically, reducing phosphorus in engine oil means reducing the content of zinc dithiophosphate. Zinc dithiophosphate is an additive having wear resistance and antioxidant properties, and reduction of zinc dithiophosphate causes a decrease in wear resistance and antioxidant properties of engine oil. Abrasion resistance and antioxidant properties could be compensated for by blending ingenuity and other additives, but it was not possible to suppress the phenomenon that the viscosity of the engine oil increased with the oxidative degradation of the engine oil. . The increase in the viscosity of the engine oil is caused by deterioration or polymerization of components contained in the engine oil, and the increase in the viscosity tends to be remarkably increased in the engine oil in which zinc dithiophosphate is reduced.

  When the viscosity of the engine oil increases, the viscosity resistance in the engine increases, so the effect of decreasing the viscosity resistance by decreasing the viscosity of the engine oil is reduced. As a result, the fuel saving function required for engine oil has also been reduced. Accordingly, there has been a demand for an engine oil that does not increase in viscosity even when engine oil with a low phosphorus and low sulfur prescription is deteriorated.

  Therefore, the viscosity increase can be achieved by combining a specific sulfur compound and an amine antioxidant to prevent the viscosity increase (see, for example, Patent Document 1) or by combining a carboxylic acid dispersant and a boric acid dispersant. There are known a method for preventing (see, for example, Patent Document 2), a method for extending the life of a lubricating oil and preventing an increase in viscosity by a combination of metal salt detergents (for example, see Patent Document 3), and the like. However, the method of Patent Document 1 has an insufficient effect of preventing an increase in viscosity with an engine oil with a reduced phosphorus content, together with a problem that sulfur compounds increase. In addition, the methods of Patent Documents 2 and 3 are insufficient in preventing the increase in viscosity of engine oil with a reduced phosphorus content, and further, basic performance required for engine oil such as wear resistance is not satisfactory. It was enough.

Japanese translation of PCT publication No. 2002-507657 JP 2003-193078 A Special table 2003-517092 gazette

  Therefore, the problem to be solved by the present invention is that even an engine oil with a low phosphorus and low sulfur formulation has oxidation stability, wear resistance, and low friction performance equivalent to or higher than those of conventional engine oils. And providing an engine oil composition in which the engine oil viscosity does not increase due to deterioration.

  Therefore, the present inventors have intensively studied an engine oil having a low phosphorus prescription, and by blending an ester compound having a specific structure, even with a low phosphorus prescription, the wear resistance, antioxidant property, sustainability and low The present inventors have found that an engine oil having excellent friction performance, no increase in viscosity even when deteriorated, and excellent fuel economy can be provided.

That is, the present invention is based on the whole engine oil composition.
As the component (A), the following general formula (1)

(Wherein R ¹ and R ² represent a hydrocarbon group, and a represents a number of 0 to 1/3) 100 to 500 ppm by mass of zinc dithiophosphate represented by phosphorus content,

  As the component (B), the following general formula (2)

(Wherein R ^{3 to} R ⁶ each represent a hydrocarbon group, and X ^{1 to} X ⁴ each represent a sulfur atom or an oxygen atom) 50 to 1500 ppm in terms of molybdenum content of sulfurized (oxy) molybdenum dithiocarbamate represented by ( C) As an ingredient, an organomolybdenum compound, which is a reaction product of an amine having a specific structure and a compound having a pentavalent or hexavalent molybdenum atom, has a molybdenum content of 50 to 1500 ppm. It is an engine oil composition characterized by containing an agent.

  The effect of the present invention is to provide an engine oil having a low phosphorus formulation that is excellent in oxidation stability, wear resistance, and low friction properties, and does not increase the viscosity of the engine oil even when the engine oil is deteriorated.

  There is no restriction | limiting in particular in the lubricating base oil used for this invention, The common lubricating oil conventionally used as a lubricating base oil, for example, mineral oil, synthetic oil, and mixtures thereof are mentioned. More specifically, poly-α-olefin, ethylene-α-olefin copolymer, polybutene, alkylbenzene, alkylnaphthalene, polyalkylene glycol, polyphenyl ether, alkyl-substituted diphenyl ether, polyol ester, dibasic acid ester, carbonate ester Synthetic oils such as silicone oils and fluorinated oils, paraffinic mineral oils, naphthenic mineral oils, or refined mineral oils obtained by purifying these can be used. These base oils may be used alone or in a mixture.

The lubricating base oil used in the present invention preferably has a sulfur content of 200 ppm or less and a viscosity at 100 ° C. in the range of 3 to ²⁰ mm ² / S. Among them, the sulfur content of 100ppm or less, preferably has a viscosity of 100 ° C. is 3 to 10 mm ² / S, the sulfur content of 100ppm or less, more preferably a viscosity of 100 ° C. is mineral oils 3 to 10 mm ² / S. Since the activity of the exhaust gas catalyst is likely to decrease, it is preferable that the sulfur content of the lubricating base oil is as low as possible.

  The component (A) of the present invention will be described. The component (A) of the present invention is zinc dithiophosphate represented by the general formula (1).

In the general formula (1), R ¹ and R ² represent a hydrocarbon group. Examples of the hydrocarbon group include an alkyl group, an alkenyl group, an aryl group, a cycloalkyl group, and a cycloalkenyl group.

  Examples of the alkyl group include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, secondary butyl, tertiary butyl, pentyl, isopentyl, secondary pentyl, neopentyl, tertiary pentyl, hexyl, secondary hexyl, heptyl, 2 Secondary heptyl, octyl, 2-ethylhexyl, secondary octyl, nonyl, secondary nonyl, decyl, secondary decyl, undecyl, secondary undecyl, dodecyl, secondary dodecyl, tridecyl, isotridecyl, secondary tridecyl, tetradecyl, secondary tetradecyl , Hexadecyl, secondary hexadecyl, stearyl, eicosyl, docosyl, tetracosyl, triacontyl, 2-butyloctyl, 2-butyldecyl, 2-hexyloctyl, 2-hexyldecyl, 2-octyldecyl, 2-hexyldecyl 2-octyldodecyl, 2-decyltetradecyl, 2-dodecyl-hexadecyl, 2-hexadecyl octadecyl, 2-tetradecyl-octadecyl, monomethyl branched - include isostearyl.

  Examples of the alkenyl group include vinyl, allyl, propenyl, isopropenyl, butenyl, isobutenyl, pentenyl, isopentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tetradecenyl, oleyl and the like.

  Examples of the aryl group include phenyl, toluyl, xylyl, cumenyl, mesityl, benzyl, phenethyl, styryl, cinnamyl, benzhydryl, trityl, ethylphenyl, propylphenyl, butylphenyl, pentylphenyl, hexylphenyl, heptylphenyl, octylphenyl, Nonylphenyl, decylphenyl, undecylphenyl, dodecylphenyl, styrenated phenyl, p-cumylphenyl, phenylphenyl, benzylphenyl, α-naphthyl, β-naphthyl group and the like can be mentioned.

  Examples of the cycloalkyl group and cycloalkenyl group include a cyclopentyl, cyclohexyl, cycloheptyl, methylcyclopentyl, methylcyclohexyl, methylcycloheptyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, methylcyclopentenyl, methylcyclohexenyl, methylcycloheptenyl group. Etc.

Among these hydrocarbon groups, R ¹ and R ² are preferably an alkyl group, and more preferably a secondary alkyl group. The number of carbon atoms is preferably 3 to 14, more preferably 3 to 10, and most preferably 3 to 8. R ¹ and R ² may be the same hydrocarbon group or different hydrocarbon groups.

In general formula (1), when a = 0, it is called neutral zinc dithiophosphate (neutral salt), and when a is 1/3, it is called basic zinc dithiophosphate (basic salt). It is.
Since zinc dithiophosphate is a mixture of these neutral and basic salts, a is represented by a number from 0 to 1/3. The number of a varies depending on the production method of zinc dithiophosphate, but is preferably 0.08 to 0.3, more preferably 0.15 to 0.3, and most preferably 0.18 to 0.3. When a is larger than 0.3, the hydrolysis stability may be deteriorated. When a is smaller than 0.08, the wear resistance of the blended lubricating oil may be deteriorated.

  The content of zinc dithiophosphate represented by the general formula (1) as the component (A) with respect to the total amount of the engine oil composition of the present invention is 100 to 500 ppm by mass, preferably 150 to 500 ppm by mass, as the phosphorus content. More preferably, it is 200-500 mass ppm, Most preferably, it is 250-500 mass ppm. When the content of the component (A) is less than 100 ppm by mass as the phosphorus content, the wear resistance and the antioxidant properties are insufficient, and when it exceeds 500 ppm by mass, the activity of the exhaust gas purification catalyst tends to decrease.

Next, (B) component of this invention is demonstrated. The component (B) of the present invention is sulfurized (oxy) molybdenum dithiocarbamate (MoDTC) represented by the general formula (1).
In General formula (1), R < ³ > -R < ⁶ > is a hydrocarbon group, for example, an alkyl group, an alkenyl group, an aryl group, a cycloalkyl group, a cycloalkenyl group etc.

  Examples of the alkyl group include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, secondary butyl, tertiary butyl, pentyl, isopentyl, secondary pentyl, neopentyl, tertiary pentyl, hexyl, secondary hexyl, heptyl, 2 Secondary heptyl, octyl, 2-ethylhexyl, secondary octyl, nonyl, secondary nonyl, decyl, secondary decyl, undecyl, secondary undecyl, dodecyl, secondary dodecyl, tridecyl, isotridecyl, secondary tridecyl, tetradecyl, secondary tetradecyl Hexadecyl, secondary hexadecyl, stearyl, icosyl, docosyl, tetracosyl, triacontyl, 2-butyloctyl, 2-butyldecyl, 2-hexyloctyl, 2-hexyldecyl, 2-octyldecyl, 2-hexyldecyl, - octyldodecyl, 2-decyltetradecyl, 2-dodecyl-hexadecyl, 2-hexadecyl octadecyl, 2-tetradecyl-octadecyl, monomethyl branched - include isostearyl and the like.

  Examples of the alkenyl group include vinyl, allyl, propenyl, butenyl, isobutenyl, pentenyl, isopentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tetradecenyl, oleyl and the like.

  As an aryl group, for example, phenyl, toluyl, xylyl, cumenyl, mesityl, benzyl, phenethyl, styryl, cinnamyl, benzhydryl, trityl, ethylphenyl, propylphenyl, butylphenyl, pentylphenyl, hexylphenyl, heptylphenyl, octylphenyl, Nonylphenyl, decylphenyl, undecylphenyl, dodecylphenyl, phenylphenyl, benzylphenyl, styrenated phenyl, p-cumylphenyl, α-naphthyl, β-naphthyl group and the like can be mentioned.

  Examples of the cycloalkyl group and cycloalkenyl group include a cyclopentyl, cyclohexyl, cycloheptyl, methylcyclopentyl, methylcyclohexyl, methylcycloheptyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, methylcyclopentenyl, methylcyclohexenyl, methylcycloheptenyl group. Etc.

R ^{3 to} R ⁶ may be the same as or different from each other, but R ^{3 to} R ⁶ are preferably different from each other in order to achieve a long drain of the engine oil composition of the present invention.

R ^{3 to} R ⁶ are preferably an alkyl group or an alkenyl group, and more preferably an alkyl group. If the carbon number is too small, the solubility in the lubricating base oil will be poor. If the carbon number is too large, the melting point will be high and the activity will be low, so R ^{3 to} R ⁶ are alkyls having 6 to 18 carbon atoms. Group is preferable, an alkyl group having 8 to 15 carbon atoms is more preferable, and an alkyl group having 8 to 13 carbon atoms is most preferable.

In the general formula ^(1), X 1 ~X ⁴ is a sulfur atom or an oxygen ^atom, all of X 1 to X ⁴ is may be a sulfur atom or an oxygen atom, four ^X 1 to X ⁴ is Although a mixture of sulfur atoms and oxygen atoms may be used, it is particularly preferable that the abundance ratio of sulfur atoms / oxygen atoms is 1/3 to 3/1 in consideration of lubricity and corrosivity.

  Next, the component (C) of the present invention will be described. The component (C) of the present invention is an organic molybdate amine salt containing no sulfur atom or phosphorus atom, and more specifically, a compound having a pentavalent or hexavalent molybdenum atom is reacted with an organic amine compound. It has been made. The organic amine compound may be any of primary amine, secondary amine, and tertiary amine. For example, primary amine such as monoalkylamine, monoalkenylamine, monoalkanolamine, monoarylamine; dialkylamine, dialkenylamine Secondary amines such as dialkanolamine and diarylamine; tertiary amines such as trialkylamine, trialkenylamine, trialkanolamine, triarylamine and pyridine. Among these, general formula (3) The secondary amine compound represented is preferred.

In the general formula (3), R ⁷ and R ⁸ are a hydrogen atom or a hydrocarbon group, and examples thereof include an alkyl group, an alkenyl group, an aryl group, a cycloalkyl group, and a cycloalkenyl group.

  Examples of the alkyl group include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, secondary butyl, tertiary butyl, pentyl, isopentyl, secondary pentyl, neopentyl, tertiary pentyl, hexyl, secondary hexyl, heptyl, 2 Secondary heptyl, octyl, 2-ethylhexyl, secondary octyl, nonyl, secondary nonyl, decyl, secondary decyl, undecyl, secondary undecyl, dodecyl, secondary dodecyl, tridecyl, isotridecyl, secondary tridecyl, tetradecyl, secondary tetradecyl Hexadecyl, secondary hexadecyl, stearyl, icosyl, docosyl, tetracosyl, triacontyl, 2-butyloctyl, 2-butyldecyl, 2-hexyloctyl, 2-hexyldecyl, 2-octyldecyl, 2-hexyldecyl, - octyldodecyl, 2-decyltetradecyl, 2-dodecyl-hexadecyl, 2-hexadecyl octadecyl, 2-tetradecyl-octadecyl, monomethyl branched - include isostearyl and the like.

  Examples of the alkenyl group include vinyl, allyl, propenyl, butenyl, isobutenyl, pentenyl, isopentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tetradecenyl, oleyl and the like.

  As an aryl group, for example, phenyl, toluyl, xylyl, cumenyl, mesityl, benzyl, phenethyl, styryl, cinnamyl, benzhydryl, trityl, ethylphenyl, propylphenyl, butylphenyl, pentylphenyl, hexylphenyl, heptylphenyl, octylphenyl, Nonylphenyl, decylphenyl, undecylphenyl, dodecylphenyl, phenylphenyl, benzylphenyl, styrenated phenyl, p-cumylphenyl, α-naphthyl, β-naphthyl group and the like can be mentioned.

  Examples of the cycloalkyl group and cycloalkenyl group include a cyclopentyl, cyclohexyl, cycloheptyl, methylcyclopentyl, methylcyclohexyl, methylcycloheptyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, methylcyclopentenyl, methylcyclohexenyl, methylcycloheptenyl group. Etc.

Among these, R ⁷ and R ⁸ are preferably an alkyl group or an alkenyl group, and more preferably an alkyl group. More specifically, R ⁷ and R ⁸ are preferably secondary amines which may be the same or different from each other. If the carbon number is too small, the solubility in the lubricating base oil becomes poor. If the carbon number is too large, the melting point increases and the activity decreases, so R ⁷ and R ⁸ have 6 to 20 carbon atoms. Alkyl groups having 8 to 18 carbon atoms are more preferable, and alkyl groups having 10 to 15 carbon atoms are most preferable.

Examples of the pentavalent or hexavalent molybdenum compound to be reacted with the amine compound represented by the general formula (3) include molybdenum trioxide or a hydrate thereof (MoO ₃ .nH ₂ O), molybdic acid (H ₂ MoO ₄ ), alkali metal molybdate (M ₂ MoO ₄ ), ammonium molybdate {(NH ₄ ) ₂ MoO ₄ or (NH ₄ ) ₆ [Mo ₇ O ₂₄ ] · 4H ₂ O}, MoCl ₅ , MoOCl ₄ , MoO ₂ Cl ₂ , MoO ₂ Br ₂ , Mo ₂ O ₃ Cl _{6 and the} like. In consideration of the yield of the organic molybdate amine salt which is a reaction product, a hexavalent molybdenum compound is preferable. Among the hexavalent molybdenum compounds, easily available molybdenum trioxide or hydrate thereof, molybdic acid, alkali metal molybdate, ammonium molybdate and the like are preferable, and molybdenum trioxide or hydrate thereof is more preferable.

  The reaction ratio between the amine compound represented by the general formula (3) and the pentavalent or hexavalent molybdenum compound is preferably a ratio of 0.5 to 5 mol of molybdenum atom with respect to 1 mol of amine. When the molar ratio of molybdenum atoms is less than 0.5, there are many free amines that have not reacted with molybdenum, and when there are more than 5, there are many unreacted molybdenum compounds. This is because the concentration of the organic molybdate amine salt in the product is lowered. A more preferable reaction ratio is 0.6 to 4 mol, most preferably 0.9 to 2.5 mol of molybdenum atom per mol of amine.

  The method for producing an organomolybdate amine salt, which is the component (C) of the present invention, comprises stirring and mixing the above amine compound and the above pentavalent or hexavalent molybdenum compound at 50 to 120 ° C. for 1 to 10 hours. do it. At this time, the reaction can be carried out by adding a solvent. Examples of the solvent that can be used include hydrocarbon organic solvents such as hexane, cyclohexane, octane, isooctane, benzene, toluene, xylene, tetralin, decalin, mineral spirit, normal paraffin, and isoparaffin; ethanol, isopropanol, butanol, and 2-ethyl. Alcohols such as hexanol, ethylene glycol, diethylene glycol, propylene glycol; non-diethyl ether, dibutyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetrahydrofuran, dimethylformamide, dimethyl sulfoxide, triphenyl phosphate, tricresyl phosphate, etc. Protic polar solvent: hydrocarbons such as gasoline, light oil, kerosene Fuel oil; mineral oils, polybutenes, hydrocarbon lubricating base oil of alkylbenzene such as, and include water. Among these solvents, water has an effect of accelerating the reaction, and 1 to 5 mol of water is preferably added to 1 mol of the amine compound, more preferably 1.5 to 4 mol. Most preferably 8 to 3 moles.

  After completion of the reaction, excess water is removed by a method such as vacuum dehydration. Other solvents may be removed as necessary. For example, when a hydrocarbon-based lubricating base oil is used, it can be used as a lubricating oil additive or the like without removing the hydrocarbon-based lubricating base oil after completion of dehydration.

  Next, (D) component of this invention is demonstrated. The component (D) of the present invention is an amine antioxidant. Examples of amine-based antioxidants include 1-naphthylamine, phenyl-1-naphthylamine, p-octylphenyl-1-naphthylamine, p-nonylphenyl-1-naphthylamine, p-dodecylphenyl-1-naphthylamine, and phenyl-2. -Naphthylamine antioxidants such as naphthylamine; N, N'-diisopropyl-p-phenylenediamine, N, N'-diisobutyl-p-phenylenediamine, N, N'-diphenyl-p-phenylenediamine, N, N ' -Di-β-naphthyl-p-phenylenediamine, N-phenyl-N'-isopropyl-p-phenylenediamine, N-cyclohexyl-N'-phenyl-p-phenylenediamine, N-1,3-dimethylbutyl-N '-Phenyl-p-phenylenediamine, dioctyl-p Phenylenediamine antioxidants such as phenylenediamine, phenylhexyl-p-phenylenediamine, phenyloctyl-p-phenylenediamine; dipyridylamine, diphenylamine, p, p'-di-n-butyldiphenylamine, p, p'-di -T-butyldiphenylamine, p, p'-di-t-pentyldiphenylamine, p, p'-dioctyldiphenylamine, p, p'-dinonyldiphenylamine, p, p'-didecyldiphenylamine, p, p'-di Diphenylamines such as dodecyldiphenylamine, p, p'-distyryldiphenylamine, p, p'-dimethoxydiphenylamine, 4,4'-bis (4-α, α-dimethylbenzoyl) diphenylamine, p-isopropoxydiphenylamine, dipyridylamine Antioxidant; phenothiazine, N- methyl phenothiazine, N- ethylphenothiazine, 3,7-dioctylphenothiazine, phenothiazine carboxylate ester, phenothiazine-based antioxidants such as phenol Serena gin and the like.

  Among these, since it is excellent in the effect which suppresses the thickening of engine oil, use of a diphenylamine antioxidant is preferable.

  In the engine oil composition of the present invention, the content of the component (B) is preferably 50 to 1500 mass ppm, more preferably 350 to 1500 mass ppm as the molybdenum content. When the molybdenum content of the component (B) is less than 50 mass ppm, the performance of reducing the friction coefficient may be inferior, or the viscosity of the engine oil may increase. If it exceeds 1500 mass ppm, it will dissolve in the lubricating base oil. In some cases, it may be difficult to cause sludge, or sludge may be generated during oxidative degradation.

  The content of the component (C) is preferably 50 to 1500 mass ppm as molybdenum content, more preferably 100 to 1000 ppm by mass, and still more preferably 100 to 700 ppm by mass. If it is less than 50 mass ppm, the viscosity of the engine oil may increase during oxidative degradation. If it exceeds 1500 mass ppm, it may be difficult to dissolve in the lubricating base oil, or sludge may be generated during oxidative degradation. There is.

  Furthermore, the total amount of the component (B) and the component (C) is preferably 1500 ppm by mass or less as the molybdenum content. If it exceeds 1500 mass ppm, it may be difficult to dissolve in the lubricating base oil, or sludge may be generated.

  The content of component (D) is preferably 0.1 to 2% by mass, more preferably 0.1 to 1.5% by mass, still more preferably 0.2 to 1.0% by mass, and 0.2 to 0. 0%. 7% by mass is most preferred. If the amount is less than 0.1% by mass, the viscosity of the engine oil may increase during oxidative degradation. If the amount exceeds 2% by mass, an effect commensurate with the amount added may not be obtained.

  The phosphorus concentration of the entire engine oil composition of the present invention is mostly due to the component (A), but some of the other components described below contain phosphorus atoms. When these components are added, the phosphorus concentration increases, but the phosphorus concentration relative to the entire engine oil composition is preferably 500 ppm or less. Moreover, 3000 ppm or less is preferable and, as for the sulfur concentration of the whole engine oil composition of this invention, 2500 ppm or less is more preferable. When these phosphorus concentration and sulfur concentration exceed the preferable ranges, the activity of the exhaust gas catalyst may be reduced.

  If it is the conventional engine oil composition which mix | blended phosphorus and the sulfur component excessively, the deterioration suppression of an engine oil composition, suppression of a viscosity rise, long life, a low friction effect, etc. are fundamentally possible. The engine oil composition of the present invention is one in which phosphorus and sulfur components are reduced as much as possible. It is known that when various additives are blended with these low phosphorus and low sulfur engine oils, the behavior of the additives changes significantly, unlike conventional engine oil compositions that contain excessive amounts of phosphorus and sulfur components. ing. The engine oil composition of the present invention can remarkably improve deterioration control, viscosity increase control, long life, and low friction effect under a different environment of low phosphorus and low sulfur.

  Furthermore, the engine oil composition of the present invention does not refuse the addition of known lubricating oil additives, and phenolic antioxidants, extreme pressure agents, oiliness improvers, detergents, dispersants depending on the purpose of use. Further, a viscosity index improver, a pour point depressant, a rust inhibitor, a corrosion inhibitor, an antifoaming agent, and the like may be added as long as the effects of the present invention are not impaired. However, when using phosphorus-based and sulfur-based additives among these, the total phosphorus content and total sulfur content in the engine oil increase, so other phosphorus compounds and sulfur compounds can be used if possible. It is preferable not to use as much as possible.

  Examples of the phenolic antioxidant include 2,6-di-tert-butylphenol (hereinafter, tertiary butyl is abbreviated as t-butyl), 2,6-di-t-butyl-p-cresol, 2 , 6-Di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-octylphenol, 2,4-dimethyl-6 -T-butylphenol, 3- (4-hydroxy-3,5-di-t-butylphenyl) propionate, decyl 3- (4-hydroxy-3,5-di-t-butylphenyl) propionate, 3 -(4-Hydroxy-3,5-di-t-butylphenyl) propionate octyl and the like. The preferable compounding quantity of these phenolic antioxidants is 0.1-1 mass% with respect to base oil.

  Examples of extreme pressure agents include sulfur additives such as sulfurized fats and oils, olefin polysulfides, and dibenzyl sulfide; phosphorus compounds such as monooctyl phosphate, tributyl phosphate, triphenyl phosphite, tributyl phosphite, and thiophosphate An organic metal compound such as a thiophosphate metal salt, a thiocarbamic acid metal salt, and an acidic phosphate metal salt; A preferable blending amount of these extreme pressure agents is 0.01 to 1% by mass with respect to the base oil.

  Examples of the oil improver include higher alcohols such as oleyl alcohol and stearyl alcohol; fatty acids such as oleic acid and stearic acid; esters such as oleyl glycerin ester, steryl glycerin ester and lauryl glycerin ester; lauryl amide and oleyl Amides such as amide and stearylamide; amines such as laurylamine, oleylamine and stearylamine; ethers such as laurylglycerol ether and oleylglycerol ether. The preferable compounding quantity of these oiliness improvers is 0.1-5 mass% with respect to base oil.

  Examples of the detergent include sulfonates such as calcium, magnesium, and barium, phenates, salicylates, phosphates, and overbased salts thereof. Of these, salicylate-based detergents having no phosphorus and sulfur atoms are preferred. The compounding quantity of these detergents is 0.5-10 mass% with respect to base oil.

  Examples of the dispersant include succinimides, succinates, benzylamines, and boron-modified products thereof to which an alkyl group or alkenyl group having a molecular weight of about 700 to 3000 is added. A preferable blending amount of these dispersants is 0.5 to 10% by mass with respect to the base oil.

  Examples of the viscosity index improver include poly (C1-18) alkyl methacrylate, (C1-18) alkyl acrylate / (C1-18) alkyl methacrylate copolymer, diethylaminoethyl methacrylate / (C1-18) alkyl methacrylate copolymer. Polymers, ethylene / (C1-18) alkyl methacrylate copolymers, polyisobutylene, polyalkylstyrene, ethylene / propylene copolymers, styrene / maleic ester copolymers, styrene / isoprene hydrogenated copolymers, and the like. . Alternatively, a dispersion-type or multifunctional viscosity index improver imparted with dispersion performance may be used. The average molecular weight is about 10,000 to 1,500,000. A preferable blending amount of these viscosity index improvers is 0.1 to 20% by mass with respect to the base oil.

  Examples of the pour point depressant include polyalkyl methacrylate, polyalkyl acrylate, polyalkyl styrene, polyvinyl acetate and the like, and the average molecular weight is 1000 to 100,000. A preferable blending amount of these pour point depressants is 0.005 to 3% by mass with respect to the base oil.

  Examples of the rust preventive include sodium nitrite, oxidized paraffin wax calcium salt, oxidized paraffin wax magnesium salt, beef tallow fatty acid alkali metal salt, alkaline earth metal salt or amine salt, alkenyl succinic acid or alkenyl succinic acid half ester (alkenyl The molecular weight of the group is about 100 to 300), sorbitan monoester, nonylphenol ethoxylate, lanolin fatty acid calcium salt and the like. The preferable compounding quantity of these rust preventives is 0.01-3 mass% with respect to base oil.

  Examples of the corrosion inhibitor include benzotriazole, benzimidazole, benzothiazole, tetraalkylthiuram disulfide, and the like. The preferable compounding quantity of these corrosion inhibitors is 0.01-3 mass% with respect to base oil.

  Examples of the antifoaming agent include polydimethyl silicone, trifluoropropylmethyl silicone, colloidal silica, polyalkyl acrylate, polyalkyl methacrylate, alcohol ethoxy / propoxylate, fatty acid ethoxy / propoxylate, sorbitan partial fatty acid ester and the like. The preferable compounding quantity of these antifoaming agents is 0.001-0.1 mass% with respect to base oil.

  The engine oil composition of the present invention can be used as a lubricating oil for internal combustion engines such as gasoline engines, diesel engines, and jet engines. Among them, it can be suitably used as a lubricating oil for gasoline engines.

  Hereinafter, the lubricating oil composition of the present invention will be described in detail by way of examples. In the following examples,% is based on mass unless otherwise specified.

  First, a mineral oil having the following properties was used as a base oil, a reference oil to which various additives were added was prepared, and the lubricant of the present invention was added thereto for testing. The properties of the base oil and the components and blending amounts used in the test are as follows.

<Base oil>
Mineral oil based advanced VI oil. Kinematic viscosity ^{4.1mm 2 /s(100℃),18.3mm 2 / s (40} ℃), viscosity index (VI) = 126, sulfur content 80ppm
<Reference oil recipe>
Base oil 100 parts by weight Methacrylate viscosity index improver 3.5 parts by weight Succinimide dispersant 5.0 parts by weight Salicylate detergent 2.5 parts by weight

<A component>
(A-1) R ¹ = 2-octyl, R ² = 2-octyl zinc dithiophosphate Phosphorus content 7.8%
(A-2) zinc dithiophosphate phosphorus content of R ¹ = n-butyl, R ² = 1-octyl 8.2%

<B component>
(B-1) In the general formula (2), R ^{3 to} R ⁶ are 2-ethylhexyl groups,
MoDTC in which X ¹ and X ² are sulfur atoms, and X ³ and X ⁴ are oxygen atoms
Molybdenum content 20.9%
(B-2) In the general formula (2), R ³ and R ⁴ are 2-ethylhexyl groups,
R ⁵ and R ⁶ are isotridecyl groups, X ¹ and X ² are sulfur atoms,
MoDTC in which X ³ and X ⁴ are oxygen atoms
Molybdenum content 18.1%

<C component>
(C-1)
A glass reaction vessel equipped with a stirrer, a dropping funnel, a thermometer, and a nitrogen introduction tube was charged with 1 mol of molybdenum trioxide and 540 g of water, and stirred under a nitrogen stream to disperse the molybdenum trioxide. Thereafter, 1.0 mol of di-n-octylamine was added dropwise over 1 hour while maintaining the temperature at 50 to 60 ° C. under a nitrogen stream, and the mixture was further aged at the same temperature for 1 hour. When placed and visually observed, the molybdenum trioxide powder dispersed in water disappeared, and the reaction solution was separated into two layers consisting of an aqueous layer and an oil layer. Thereafter, the water layer was separated, and the oil layer was depressurized to 100 kPa or lower to 1.4 kPa or less to remove moisture, thereby obtaining pale blue oily C-1. Moreover, in the IR analysis of C-1, since absorption near 990 cm ⁻¹ derived from molybdenum trioxide disappeared, it was confirmed that the raw material molybdenum trioxide was completely reacted. Molybdenum content 23.8%
(C-2)
C-2 was obtained in the same manner as MoAm1 except that 1.0 mol of mono-beef tallow-derived alkylamine was used instead of C-1 di-n-octylamine. IR analysis of C-2 confirmed that the raw material molybdenum trioxide was completely reacted. Molybdenum content 22.4%

<D component>
(D-1) p, p'-didodecyldiphenylamine (D-2) phenyloctyl-p-phenylenediamine

<Other ingredients>
(E-1) 3- (4-Hydroxy-3,5-di-t-butylphenyl) propionic acid
Octyl

（カッコ内は配合量で単位は質量％、下段はそれぞれの添加剤の組成物全体に対するリン又はモリブデン量）

(The amount in parentheses is the amount, the unit is mass%, the lower row is the amount of phosphorus or molybdenum with respect to the total composition of each additive)

The composition shown in Table 1 was tested by the following method.
<Degradation test of test oil>
In accordance with JIS K-2514 (lubricating oil-oxidation stability test method), 250 ml of the sample shown in Table 1 is placed in a glass container containing a copper plate and an iron plate as a catalyst, and air is introduced at 1300 rpm. The test oil was oxidized and deteriorated by heating at 165.5 ° C. for 168 hours with stirring. Kinematic viscosity (40 ° C.) was measured for the test oil before and after the deterioration test. From the results, it is shown that the smaller the viscosity ratio (the value obtained by dividing the deteriorated kinematic viscosity by the kinematic viscosity before deterioration), the viscosity does not increase even when deteriorated. Moreover, the test oil after deterioration was filtered with a filter paper, washed thoroughly with hexane and dried, and the weight of sludge was measured.

<Lubrication performance test>
Using the lubricating composition (new oil) of the product of the present invention and the comparative product, the average friction coefficient and the conditions under a load of 30 kg, room temperature, rotation speed of 1,500 rpm, and time of 10 minutes using a shell type high-speed four-ball tester The wear scar diameter of the ball was measured.

  If the amount of sludge is less than 0.1 g, it can be judged that there is good oxidation stability, so it can be seen that all the products of the present invention have good oxidation stability. In addition, if the average coefficient of friction is 0.1 or less, it is called a low friction engine oil. Therefore, it can be seen that all the products of the present invention have low friction performance. Furthermore, it can be said that if the wear scar is less than 0.3 mm, it shows good wear resistance, so that all the products of the present invention have good wear resistance. And as for the viscosity after degradation of the product of the present invention, an increase is clearly suppressed. From the above results, it was confirmed that the engine oil composition of the present invention is an engine oil that has good oxidation stability, low friction properties, and wear resistance, and does not increase in viscosity even when deteriorated.

Claims (7)

For the whole engine oil composition,
As the component (A), the following general formula (1)

(In the formula, R ¹ and R ² represent a hydrocarbon group, and a represents a number of 0 to 1/3.)
100-500 mass ppm as a phosphorus content zinc dithiophosphate represented by
As the component (B), the following general formula (2)

(Wherein R ^{3 to} R ⁶ represent a hydrocarbon group, and X ^{1 to} X ⁴ represent a sulfur atom or an oxygen atom) 50 to 1500 ppm in terms of molybdenum content of sulfurized (oxy) molybdenum dithiocarbamate represented by
As the component (C), the following general formula (3)

(Wherein R ⁷ and R ⁸ represent a hydrogen atom or a hydrocarbon group, but are not simultaneously a hydrogen atom) and a compound having a pentavalent or hexavalent molybdenum atom An engine oil composition comprising an organic molybdenum compound as a reactant in a molybdenum content of 50 to 1500 ppm, and an amine-based antioxidant as a component (D).   The engine oil composition according to claim 1, wherein the phosphorus concentration of the entire engine oil composition is 500 ppm or less.   The engine oil composition according to claim 1 or 2, wherein a sulfur concentration of the whole engine oil composition is 3000 ppm or less. (D), wherein the component is a diphenylamine-based antioxidant, an engine oil composition according to any one of claims 1-3. A 50~500ppm as the component (C) is molybdenum content, (B), wherein the component and (C) a total molybdenum content of components is less than 1500 ppm, of any of claims 1-4 Engine oil composition. The engine oil composition according to any one of claims 1 to 5 , wherein the component (D) is 0.1 to 2.0 mass% with respect to the engine oil composition. One selected from the group consisting of phenolic antioxidants, extreme pressure agents, oiliness improvers, detergents, dispersants, viscosity index improvers, pour point depressants, rust inhibitors, corrosion inhibitors and antifoaming agents Or the engine oil composition in any one of Claims 1-6 characterized by containing 2 or more types.