JP4467283B2 - Lubricating oil composition for engine - Google Patents

Description

  The present invention relates to an engine lubricating oil composition, and more particularly to an engine lubricating oil composition that is excellent in high-temperature cleanliness even if it does not substantially contain a phosphorus-containing compound such as zinc dithiophosphate.

In the field of engine oils, zinc dithiophosphate, an antiwear and antioxidant agent, has been used for over 50 years and is now recognized as an essential engine oil additive.
By the way, against the background of environmental problems in recent years, oxidation catalysts, three-way catalysts, NOx occlusion-type reduction catalysts, etc. are used for engines such as automobiles. Recently, diesel particulate removal devices such as DPF are installed. Emission regulations are being tightened.
Under such circumstances, many studies have been made on the influence of engine lubricating oil on the exhaust gas aftertreatment device as described above. For example, in Patent Documents 1 to 15, low phosphorus or phosphorus-free engine oil, low ash or low sulfur engine oil has been studied in order to reduce the load on the exhaust gas aftertreatment device.
However, in such a conventional engine oil, a high amount of a sulfur-containing additive for maintaining wear prevention performance is blended in place of the zinc dithiophosphate, so that the high-temperature cleanliness deteriorates, and the low ash engine In oil, zinc dithiophosphate is blended as an essential component in order to maintain various performances, or it is either an ashless engine oil that does not contain a metallic detergent.
Therefore, it is considered that there are few examples of study of a substantially phosphorus-free and low-ash engine lubricating oil composition that is extremely excellent in high-temperature cleanliness without containing zinc dithiophosphate.
JP-A-62-253691 JP-A-6-41568 Japanese translation of PCT publication 1-500912 Japanese Patent Laid-Open No. 63-304095 JP-A 63-304096 Japanese Patent Laid-Open No. Sho 62-243692 JP-T 62-501917 JP 62-501572A JP 2000-63862 A JP 2002-206096 A Japanese Patent Application Laid-Open No. 2003-073685 Japanese Patent Laid-Open No. 8-48989 Japanese Patent Laid-Open No. 8-253782 JP-A-9-111275 JP 2000-256690 A

  As a result of investigating the high temperature cleaning performance of low ash or non-phosphorus low ash engine oils centered on typical overbased sulfonates commonly used in engine oils, It was found to be maintained by the combined use of a system detergent and zinc dithiophosphate. On the other hand, it has been found that low-phosphorus or non-phosphorus-free low ash engine oils with reduced metal detergents and extremely reduced zinc dithiophosphate have extremely high temperature cleanliness. That is, it has been found that engine oil phosphorus-free and low ash reduction for reducing the influence on the exhaust gas purification device as much as possible cannot be simply achieved.

Therefore object of the present invention, even in a low ash engine oil a phosphorus-containing compound containing no phosphorus-free, such as zinc dithiophosphate, provides to optimize the lubricating oil composition engine lubricating oil composition having excellent high-temperature detergency It is to be.

The present inventors have found that the main component result of extensive investigations to solve the above problems, in the engine oil-free phosphorus, ashless dispersant, an additive consisting of ashless antioxidant and a specific metallic detergent As a result, the present inventors have found that the low ash engine oil contained in the present invention is excellent in high-temperature cleanliness and has completed the present invention.
That is, according to the present invention, a phosphorus-containing compound to a lubricating oil composition for containing no engine, the lubricating base oil, and (A) an ashless dispersant, and (B) an ashless antioxidant, ( C) an additive comprising a neutral metal salicylate detergent as a main component, the content of the component (C) being 0.11 to 0.15% by mass in terms of metal element, and composition The lubricating oil composition for engines is provided, wherein the sulfated ash content of the product is 0.5% by mass or less.

  The engine lubricating oil composition of the present invention is not only excellent in high-temperature cleanliness, but also can eliminate concerns about the influence of phosphorus on the exhaust gas after-treatment device, and further can reduce ash and sulfur, It is possible to eliminate concerns about the influence on the device, and it is extremely useful as an environment-friendly engine oil.

Hereinafter, the present invention will be described in more detail.
Engine lubricating oil compositions of the present invention, Li down a composition not containing containing compounds, lubricating engine capable dispel effect concerns the exhaust aftertreatment device due to the phosphorus-containing compounds such as zinc dithiophosphate It is an oil composition.

The lubricating base oil used in the composition of the present invention is not particularly limited, and a mineral base oil and / or a synthetic base oil used for ordinary lubricating oils can be used.
Specifically, as the mineral base oil, the lubricating oil fraction obtained by subjecting the crude oil to atmospheric distillation obtained under reduced pressure is subjected to solvent removal, solvent extraction, hydrocracking, Produced by isomerizing GTL WAX (Gas Liquid Liquid) produced by one or more treatments such as solvent dewaxing or hydrorefining, or wax isomerized mineral oil, Fischer-Tropsch process, etc. Lubricating oil base oil and the like can be exemplified.

The total aromatic content in the mineral oil base oil is not particularly limited, but is preferably 15% by mass or less, more preferably 10% by mass or less, further preferably 5% by mass or less, and particularly preferably 2% by mass or less. . When the total aromatic content of the base oil exceeds 15% by mass, oxidation stability is inferior, which is not preferable.
Here, the total aromatic content means the aromatic fraction content measured according to ASTM D2549. Usually, this aromatic fraction includes alkylbenzene, alkylnaphthalene, anthracene, phenanthrene, and alkylated products thereof, compounds in which four or more benzene rings are condensed, or pyridines, quinolines, phenols, naphthols, etc. Compounds having heteroaromatics and the like are included.
The amount of sulfur in the mineral oil base oil is not particularly limited, but is preferably 0.05% by mass or less, more preferably 0.01% by mass or less, and further preferably 0.005% by mass or less. By reducing the sulfur content of the mineral oil base oil, a composition having better high temperature cleanability can be obtained.

  Specific examples of synthetic base oils include polybutene or hydrides thereof; poly α-olefins such as 1-octene oligomers and 1-decene oligomers or hydrides thereof; ditridecyl glutarate, di-2-ethylhexyl adipate, Diesters such as diisodecyl adipate, ditridecyl adipate, or di-2-ethylhexyl sebacate; polyol esters such as trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol-2-ethylhexanoate, or pentaerythritol pelargonate A copolymer of a dicarboxylic acid such as dibutyl maleate and an α-olefin having 2 to 30 carbon atoms, an aromatic synthetic oil such as an alkyl naphthalene, an alkyl benzene, or an aromatic ester, or a mixture of two or more of these Things can be exemplified.

As the lubricating base oil used in the present invention, a mineral base oil, a synthetic base oil, or an arbitrary mixture of two or more kinds of lubricating base oils selected from these can be used. Examples thereof include one or more mineral base oils, one or more synthetic base oils, a mixed oil of one or more mineral base oils and one or more synthetic base oils, and the like.
No particular limitation is imposed kinematic viscosity of the lubricating base oil used in the present invention, the kinematic viscosity at the 100 ° C. is, 1 mm ² / s or more, is preferably from ^{20mm 2 / s, 2mm 2 /} s or more, 10 mm ² / S or less is more preferable. When the kinematic viscosity at 100 ° C. of the lubricating base oil exceeds 20 mm ² / s, the low-temperature viscosity characteristic deteriorates. On the other hand, when the kinematic viscosity is less than 1 mm ² / s, an oil film is formed at the lubricating point. Since it is insufficient, the lubricity is inferior, and the evaporation loss of the lubricating base oil becomes large.

  The evaporation loss amount of the lubricating base oil is preferably 20% by mass or less, more preferably 16% by mass or less, and particularly preferably 10% by mass or less in terms of NOACK evaporation. If the NOACK evaporation amount of the lubricant base oil exceeds 20% by mass, not only the evaporation loss of the lubricant base oil is large, but also the sulfur compound, phosphorus compound, or metal component in the composition is exhaust gas purified together with the lubricant base oil. There is a possibility of accumulating in the apparatus, which not only increases the oil consumption but also adversely affects the exhaust gas purification performance. Here, the NOACK evaporation amount is a value obtained by measuring the evaporation amount of the lubricating oil measured according to ASTM D5800.

  The viscosity index of the lubricating base oil is not particularly limited, but the value is preferably 80 or more, more preferably 100 or more, and most preferably 120 or more so that excellent viscosity characteristics can be obtained from low temperature to high temperature. There is no particular limitation on the upper limit of the viscosity index, normal paraffin, slack wax, GTL wax or the like, or those of about 135 to 180 such as isoparaffinic mineral oil obtained by isomerizing these, complex ester base oil or HVI-PAO system The thing of about 150-250 like base oil can also be used. When the viscosity index of the lubricating base oil is less than 80, the low temperature viscosity characteristics deteriorate, which is not preferable.

As the (A) ashless dispersant (hereinafter sometimes referred to as the component (A)) used in the composition of the present invention, any ashless dispersant used in lubricating oils can be used, for example, 40 to 400 carbon atoms, preferably Includes a nitrogen-containing compound having at least one linear or branched alkyl group or alkenyl group of 60 to 350 or a derivative thereof, a Mannich dispersant, or a modified product of alkenyl succinimide. In use, one kind or two or more kinds arbitrarily selected from these can be blended.
In the case where the carbon number of the alkyl group or alkenyl group of the nitrogen-containing compound or derivative thereof is less than 40, the solubility in the lubricating oil base oil is reduced, whereas in the case where the carbon number of the alkyl group or alkenyl group exceeds 400, The low-temperature fluidity of the lubricating oil composition is deteriorated, which is not preferable. The alkyl group or alkenyl group may be linear or branched, but is preferably derived from, for example, an olefin oligomer such as propylene, 1-butene, isobutylene, or a co-oligomer of ethylene and propylene. Examples include branched alkyl groups and branched alkenyl groups.

As the component (A), for example, one or more compounds selected from the following components (A ¹ ) to (A ³ ) can be used.
(A ¹⁾ at least one having succinimide or its derivative, an alkyl group or an alkenyl group having 40 to 400 carbon atoms in the molecule,
(A ²⁾ at least one having benzylamine or its derivatives, an alkyl group or an alkenyl group having 40 to 400 carbon atoms in the molecule,
(A ³ ) A polyamine having at least one alkyl group or alkenyl group having 40 to 400 carbon atoms in the molecule, or a derivative thereof.

式(１)中、Ｒ²⁰は炭素数４０〜４００、好ましくは６０〜３５０のアルキル基又はアルケニル基を示し、ｈは１〜５、好ましくは２〜４の整数を示す。一方、式(２)中、Ｒ²¹及びＲ²²は、それぞれ個別に炭素数４０〜４００、好ましくは６０〜３５０のアルキル基又はアルケニル基を示し、特に好ましくはポリブテニル基である。またｉは０〜４、好ましくは１〜３の整数を示す。 Examples of the component (A ¹ ) include compounds represented by the formula (1) or (2).

In the formula (1), R ²⁰ represents an alkyl group or alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350, and h represents an integer of 1 to 5, preferably 2 to 4. On the other hand, in the formula (2), R ²¹ and R ²² each independently represents an alkyl group or alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350 carbon atoms, and particularly preferably a polybutenyl group. I represents an integer of 0 to 4, preferably 1 to 3.

The component (A ¹ ) includes a so-called monotype succinimide represented by the formula (1) in which succinic anhydride is added to one end of the polyamine, and a formula (2) in which succinic anhydride is added to both ends of the polyamine. The so-called bis-type succinimide represented by the formula (1) is included, and the composition of the present invention may contain any of them or a mixture thereof.
These (A ¹⁾ preparation of succinimide as the component is not particularly limited, for example, a compound having an alkyl or alkenyl group having 40 to 400 carbon atoms, are reacted in a 100 to 200 ° C. maleic anhydride obtained It can be obtained by reacting an alkyl or alkenyl succinic acid with a polyamine.
Specific examples of the polyamine include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine.

式(３)中、Ｒ²³は炭素数４０〜４００、好ましくは６０〜３５０のアルキル基又はアルケニル基を示し、ｊは１〜５、好ましくは２〜４の整数を示す。
この(Ａ²)成分であるベンジルアミンの製法は特に制限はなく、例えば、プロピレンオリゴマー、ポリブテン、又はエチレン−α−オレフィン共重合体等のポリオレフィンを、フェノールと反応させてアルキルフェノールとした後、これにホルムアルデヒドと、ジエチレントリアミン、トリエチレンテトラミン、テトラエチレンペンタミン、又はペンタエチレンヘキサミン等のポリアミンとをマンニッヒ反応により反応させることにより得られる。 Specific examples of the component (A ² ) include compounds represented by the formula (3).

In the formula (3), R ²³ represents an alkyl group or alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350, and j represents an integer of 1 to 5, preferably 2 to 4.
There is no particular limitation on the production method of the benzylamine which is the component (A ² ). For example, a polyolefin such as a propylene oligomer, polybutene, or ethylene-α-olefin copolymer is reacted with phenol to obtain an alkylphenol. It is obtained by reacting formaldehyde with a polyamine such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, or pentaethylenehexamine by a Mannich reaction.

Specific examples of the component (A ³ ) include compounds represented by the formula (4).
_{^{R 24 -NH- (CH 2 CH 2}} NH) k -H (4)
In the formula (4), R ²⁴ represents an alkyl or alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350, and k represents an integer of 1 to 5, preferably 2 to 4.
The production method of the polyamine which is the component (A ³ ) is not particularly limited. For example, after chlorinating a polyolefin such as a propylene oligomer, polybutene, and an ethylene-α-olefin copolymer, ammonia, ethylenediamine, diethylenetriamine, It can be obtained by reacting a polyamine such as triethylenetetramine, tetraethylenepentamine, or pentaethylenehexamine.

Examples of the derivative of the nitrogen-containing compound mentioned as an example of the component (A) include, for example, monocarboxylic acids having 1 to 30 carbon atoms (fatty acids, etc.), oxalic acid, phthalic acid, trimellitic acid C2-30 polycarboxylic acids such as pyromellitic acid or their anhydrides or ester compounds; alkylene oxides having 2-6 carbon atoms; hydroxy (poly) oxyalkylene carbonate, etc. A modified compound by a so-called oxygen-containing organic compound obtained by neutralizing or amidating some or all of the group and / or imino group; boric acid is allowed to act on the above-mentioned nitrogen-containing compound, and the remaining amino group and / or A so-called boron-modified compound in which part or all of the imino group is neutralized or amidated; a residual amino compound obtained by allowing phosphoric acid to act on the aforementioned nitrogen-containing compound And / or a so-called phosphoric acid-modified compound obtained by neutralizing or amidating a part or all of the imino group; a sulfur-modified compound obtained by allowing a sulfur compound to act on the nitrogen-containing compound described above; and the nitrogen-containing compound described above. Examples thereof include modified compounds in which two or more kinds of modifications selected from modification with oxygen organic compounds, boron modification, phosphoric acid modification, and sulfur modification are combined. Among these derivatives, the boric acid modified compound of alkenyl succinimide is excellent in heat resistance and antioxidant property, and is effective in further improving the base number maintenance in the lubricating oil composition of the present invention.
In the present invention, it is particularly desirable to use unmodified alkenyl succinimide and boric acid-modified alkenyl succinimide in combination.

  In the composition of the present invention, the content of the component (A) is usually 0.1 to 20% by mass, preferably 4 to 15% by mass, based on the total amount of the composition. When the content of the component (A) is less than 0.1% by mass, the effect on the high-temperature cleanability is small. On the other hand, when the content exceeds 20% by mass, the low-temperature fluidity of the composition is greatly deteriorated, which is not preferable. .

The (B) ashless antioxidant used in the composition of the present invention (hereinafter sometimes referred to as the component (B)) is generally used in lubricating oils such as phenolic antioxidants and amine antioxidants. If it is, it can be used. By using the component (B), the high temperature cleanability of the composition can be enhanced.
Examples of the phenolic antioxidant as the component (B) include 4,4′-methylenebis (2,6-di-tert-butylphenol), 4,4′-bis (2,6-di-tert-butylphenol). ), 4,4′-bis (2-methyl-6-tert-butylphenol), 2,2′-methylenebis (4-ethyl-6-tert-butylphenol), 2,2′-methylenebis (4-methyl-6) -Tert-butylphenol), 4,4'-butylidenebis (3-methyl-6-tert-butylphenol), 4,4'-isopropylidenebis (2,6-di-tert-butylphenol), 2,2'-methylenebis (4-methyl-6-nonylphenol), 2,2'-isobutylidenebis (4,6-dimethylphenol), 2,2'-methylenebis (4-methyl-6-cyclohexylphenol), 2,6-di -Tert-butyl-4- Methylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,4-dimethyl-6-tert-butylphenol, 2,6-di-tert-α-dimethylamino-p-cresol, 2,6 -Di-tert-butyl-4- (N, N'-dimethylaminomethylphenol), 4,4'-thiobis (2-methyl-6-tert-butylphenol), 4,4'-thiobis (3-methyl- 6-tert-butylphenol), 2,2′-thiobis (4-methyl-6-tert-butylphenol), bis (3-methyl-4-hydroxy-5-tert-butylbenzyl) sulfide, bis (3,5- Di-tert-butyl-4-hydroxybenzyl) sulfide, 2,2′-thio-diethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], tridecyl-3- (3 , 5-Di-tert- Til-4-hydroxyphenyl) propionate, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octyl-3- (3,5-di-tert-butyl) -4-hydroxyphenyl) propionate, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, octyl-3- (3-methyl-5-di-tert-butyl-4-hydroxy Phenyl) propionate and the like can be mentioned as preferred examples. You may use these in mixture of 2 or more types.

式(５)において、Ｒ³⁰及びＲ³¹は同一又は異なる基であって炭素数１〜４のアルキル基を示し、少なくとも一方がｔ−ブチル基であることが好ましく、また一方がメチル基で、他方がｔ−ブチル基であることがより好ましい。Ｒ³²は炭素数１〜６のアルキレン基を示し、好ましくはエチレン基(ジメチレン基)である。Ｒ³³は炭素数１〜２２のアルキル基又はアルケニル基を示し、好ましくは炭素数４〜１８のアルキル基、より好ましくは炭素数６〜１２のアルキル基を示す。 Of these phenol-based antioxidants, alkylhydroxyphenyl group-substituted fatty acid ester-based antioxidants are preferred in that the effect of improving high-temperature cleanliness with respect to the amount added is higher, and among them, 3,5-represented by formula (5) Alkyl-4-hydroxyphenyl group-substituted fatty acid ester antioxidants are most preferred.

In the formula (5), R ³⁰ and R ³¹ are the same or different groups and represent an alkyl group having 1 to 4 carbon atoms, preferably at least one is a t-butyl group, and one is a methyl group, More preferably, the other is a t-butyl group. R ³² represents an alkylene group having 1 to 6 carbon atoms, preferably an ethylene group (dimethylene group). R ³³ represents an alkyl group or alkenyl group having 1 to 22 carbon atoms, preferably an alkyl group having 4 to 18 carbon atoms, more preferably an alkyl group having 6 to 12 carbon atoms.

As the amine-based antioxidant as the component (B), for example, it is generally used for lubricating oils such as aromatic amine compounds, alkyldiphenylamines, alkylnaphthylamines, phenyl-α-naphthylamines, alkylphenyl-α-naphthylamines and the like. A well-known amine antioxidant is mentioned. Here, the alkyl group means an alkyl group having 1 to 30 carbon atoms, preferably 3 to 20 carbon atoms, particularly preferably 4 to 10 carbon atoms.
(B) As a component, it is preferable to mix | blend the said phenolic antioxidant and amine antioxidant in combination.

  In the composition of the present invention, the content of the component (B) is usually 0.1 to 20% by mass, preferably 0.5 to 10% by mass, particularly preferably 1 to 5% by mass based on the total amount of the composition. When the content exceeds 20% by mass, it is not preferable because sufficient high temperature cleanliness corresponding to the blending amount may not be obtained.

Examples of the (C) neutral metal salicylate detergent (hereinafter sometimes referred to as the component (C)) used in the composition of the present invention include known alkali metal or alkaline earth metal salicylates. Here, examples of the alkali metal include sodium and potassium, and examples of the alkaline earth metal include calcium and magnesium, and calcium is particularly preferable.
As the component (C), the use of neutral calcium salicylate is particularly preferable from the viewpoint of better high-temperature cleanability.
The metal ratio of the component (C) is usually 1.5 or less, preferably 1.3 or less, and may contain a slight amount of an overbased component such as calcium carbonate, but the metal ratio is particularly preferably 1 ( Does not contain overbased components). Here, the metal ratio is represented by the valence of the metal element in the metal salicylate detergent × metal element content (mole) / soap group content (mole), where the metal is an alkali metal or alkaline earth metal, soap. The group represents a salicylic acid group. The total base number of component (C) is usually 0 to 120 mgKOH / g, preferably 10 to 100 mgKOH / g. However, commercially available neutral metal detergents usually contain diluent oil, and calcium salicylate Usually, 50 to 80 mg KOH / g is available.

In the composition of the present invention, the content of the component (C) is usually 0.11 to 0.15% by mass, preferably 0.11 to 0.12% by mass in terms of metal element, based on the total amount of the composition. is there. When the content of component (C) in terms of metal element exceeds 0.15% by mass, the sulfated ash content of the composition is set to 0.5% by mass or less to suppress the influence on the exhaust gas aftertreatment device. The low ash engine oil of the present invention which is intended to be used may not be obtained, which is not preferable.

The engine lubricating oil composition of the present invention contains the component (A), the component (B), and the component (C) in the lubricating base oil, but is required to further improve the performance or otherwise. In order to add performance, any additive commonly used in lubricating oils can be added depending on the purpose. Examples of such additives include antioxidants other than the component (B), metallic detergents other than the component (C), wear inhibitors, friction modifiers, viscosity index improvers, corrosion inhibitors, rust inhibitors And additives such as agents, demulsifiers, metal deactivators, antifoaming agents, and coloring agents.
Examples of the antioxidant other than the component (B) include copper-based and molybdenum-based metal-based antioxidants.
As the metal detergent other than the component (C), neutral metal sulfonate detergent, neutral metal phenate detergent, basic or overbased metal sulfonate detergent, basic or overbased metal salicylate A detergent, a basic or overbased metal phenate detergent, etc. can be used, and can be used in combination to further improve the effect of the present invention or unless the effect of the present invention is significantly inhibited. In that case, it is desirable to mix | blend so that the amount of sulfated ash content of a composition may be 0.5 mass% or less.

The antiwear agents, For example, di-thiocarbamates, zinc dithiocarbamate, molybdenum dithiocarbamate, disulfides, sulfurized olefins, sulfurized fats and oils and the like can be mentioned, et al are.
Further, among these antiwear agents, the content of the sulfur-containing compound is not particularly limited and can be blended as long as the effect of the present invention is not significantly deteriorated, but it is necessary to reduce the influence on the exhaust gas purification device as much as possible. In view of the properties, the content is preferably 0.15% by mass or less, more preferably 0.1% by mass or less, and particularly preferably 0.05% by mass or less in terms of elemental sulfur based on the total amount of the composition. .

The friction modifier, for example, include dithiocarbamates molybdenum, molybdenum disulfide, aliphatic amines having a hydrocarbon group having 6 to 30 carbon atoms, fatty acids, fatty acid esters, fatty acid amides, aliphatic ethers or aliphatic alcohols and the like It is done. In particular, tertiary amine compounds are more preferred because they can further enhance the high temperature cleanliness.
The content of the friction modifier is not particularly limited as long as the effect of the present invention is not significantly deteriorated, but is usually 0.1 to 5% by mass based on the total amount of the composition. By using the friction modifier in combination, fuel saving performance can be further improved.
As the viscosity index improver, polymethacrylate viscosity index improver, olefin copolymer viscosity index improver, styrene-diene copolymer viscosity index improver, styrene-maleic anhydride copolymer viscosity index improver or poly Examples thereof include alkylstyrene viscosity index improvers.
The weight average molecular weight of the viscosity index improver is usually 800 to 1,000,000, preferably 100,000 to 900,000.
The content of the viscosity index improver is usually 0.1 to 20% by mass based on the total amount of the composition.

Examples of the corrosion inhibitor include benzotriazole, tolyltriazole, thiadiazole, or imidazole compounds.
Examples of the rust preventive include petroleum sulfonate, alkylbenzene sulfonate, dinonylnaphthalene sulfonate, alkenyl succinic acid ester, and polyhydric alcohol ester.
Examples of the demulsifier include polyalkylene glycol nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, or polyoxyethylene alkyl naphthyl ether.
Examples of metal deactivators include imidazoline, pyrimidine derivatives, alkylthiadiazoles, mercaptobenzothiazoles, benzotriazoles or derivatives thereof, 1,3,4-thiadiazole polysulfide, 1,3,4-thiadiazolyl-2,5-bis. Examples thereof include dialkyldithiocarbamate, 2- (alkyldithio) benzimidazole, and β- (o-carboxybenzylthio) propiononitrile.
Examples of the antifoaming agent include silicone, fluorosilicol, or fluoroalkyl ether.

  When these additives are contained in the engine lubricating oil composition of the present invention, the content is based on the total amount of the composition, and is usually 0.005 to 5 mass for each of the corrosion inhibitor, rust inhibitor and demulsifier. %, Usually in the range of 0.005 to 1% by mass for the metal deactivator, and usually in the range of 0.0005 to 1% by mass for the antifoaming agent.

In the composition of the present invention, the sulfated ash content is usually 0.5% by mass or less, preferably 0.1 to 0.5% by mass, and particularly preferably 0.3 to 0.5% by mass. Here, the sulfated ash is JIS K2272 5. The value measured by the method specified in “Testing method for sulfated ash” is mainly attributed to the metal-containing additive.
The composition of the present invention preferably also reduces the content of sulfur-containing compounds, and the total sulfur content of the composition is 0.2% by mass or less, preferably 0.1% by mass or less, more preferably 0. 0.05% by mass or less.

The present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples.
In addition, each component in a table | surface is as follows.
1) Lubricating base oil: hydrocracked mineral oil (100 ° C. kinematic viscosity: 4.2 mm ² / s, sulfur content: 0.001% by mass, viscosity index: 120)
2) (A) Ashless dispersant: polybutenyl succinimide and boronated polybutenyl succinimide
3) (B) Ashless antioxidant: octyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate and alkyldiphenylamine (alkyl group: 4 to 8 carbon atoms)
4) (C) Metal detergent
(C ¹ ) Metal-based detergent: Calcium salicylate (total base number: 70 mgKOH / g)
(C ² ) Metal-based detergent: Overbased calcium sulfonate (total base number: 300 mgKOH / g)
(C ³ ) Metal-based detergent: Overbased calcium phenate (total base number: 250 mgKOH / g)
(C ⁴⁾ a metallic detergent: overbased calcium salicylate (total base number: 170 mg KOH / g)
5) Phosphorus-containing compound: zinc dialkyldithiophosphate
6) Other additives: Viscosity index improver and antifoaming agent

Example 1, Comparative Examples 1-5
An engine lubricating oil composition (Example 1) of the present invention having the composition shown in Table 1 and a comparative engine lubricating oil composition (Comparative Examples 1 to 5) were prepared. In any of these, the sulfated ash content of the composition is adjusted to 0.4% by mass.
The obtained composition was subjected to a hot tube test at 280 ° C. in accordance with JPI-5S-5599. The score was 10 points for colorless and transparent (no stain) and 0 point for black opaque, and the evaluation was made with reference to a standard tube prepared in advance by 1 interval. In this test, the rating of Comparative Example 3 containing 0.05% by mass of zinc dithiophosphate in terms of phosphorus element (equivalent level of JASO DH-1 standard, which is a high performance diesel engine oil standard) is equal to or higher than that. When showing a score, it was judged that the high temperature cleanliness was shown.

From Table 1, the composition of Comparative Example 3 contains 0.05% by mass of zinc dithiophosphate in terms of phosphorus element and overbased calcium sulfonate, and the composition has a sulfated ash content of 0.4% by mass. It is a low phosphorus low ash engine oil with a rating of 7. In the composition (Comparative Example 2) having a phosphorus amount of 0.025% by mass, the score is not changed, and when no zinc dithiophosphate is blended (Comparative Example 1), the score is 1, and the high-temperature cleaning performance is metal-based cleaning. It is maintained by the combined use of the agent and zinc dithiophosphate, and it can be seen that further low phosphatization or non-phosphorization deteriorates the high temperature cleaning performance. In addition, even when overbased phenate and overbased salicylate are used (Comparative Examples 4 and 5), it can be seen that high-temperature cleanliness is similarly poor when zinc dithiophosphate is not used.
On the other hand, when the neutral metal salicylate detergent according to the present invention is used (Example 1), the score is 8 even without using zinc dithiophosphate, and even when it is substantially phosphorus-free, the temperature is high. It can be seen that it has clean performance.

Claims (3)

A phosphorus-containing compound to a lubricating oil composition for containing no engine,
The lubricant base oil contains, as a main component, an additive comprising ( A) an ashless dispersant, (B) an ashless antioxidant, and (C) a neutral metal salicylate detergent, a 0.11 to 0.15 wt% in the content of the metal element in terms of the component, and engine lubricating oil composition characterized by sulfated ash content of the composition is less than 0.5 wt% . The content of the component (A) is 0.1 to 20% by mass and the content of the component (B) is 0.1 to 20 % by mass based on the total amount of the composition. The lubricating oil composition for engines as described.   The engine lubricating oil composition according to claim 1 or 2, wherein the component (B) contains an alkylhydroxyphenyl group-substituted fatty acid ester antioxidant.