WO2003027216A1

WO2003027216A1 - Lubricating oil composition for internal combustion engine

Info

Publication number: WO2003027216A1
Application number: PCT/JP2002/009124
Authority: WO
Inventors: Shinichi Shirahama; Yasuhisa Yamada; Isao Kurihara
Original assignee: Nippon Oil Corporation
Priority date: 2001-09-20
Filing date: 2002-09-06
Publication date: 2003-04-03
Also published as: CN1322103C; JP4185307B2; CN1556846A; EP1437396B1; US20040176260A1; EP1437396A1; JP2003165992A; EP1437396A4

Abstract

A lubricating oil composition for internal combustion engines which is excellent in antiwear performance and high-temperature detergency although reduced in ash content and is especially suitable for use in diesel engines equipped with an exhaust-gas post-treatment device. The lubricating oil composition for internal combustion engines comprises a base oil comprising a mineral oil and/or a synthetic oil and, incorpoarted therein, (A) 0.08 to 0.40 wt.% ash-free succinimide dispersant in terms of nitrogen amount, (B) 0.06 to 0.22 wt.% metallic detergent in terms of metal element amount, (C) 0.04 to 0.08 wt.% zinc (sec-alkyl)dithiophosphate in terms of phosphorus amount, and (D) 0.01 to 0.04 wt.% ash-free phosphorus-compound antiwear agent in terms of phosphorus amount. The content of sulfated ashes derived from metal elements in the composition is 0.3 to 1.0 wt.%.

Description

Description Lubricating oil composition for internal combustion engine

[Technical field]

The present invention relates to a lubricating oil composition for an internal combustion engine. In particular, it relates to a low-ash type diesel engine oil suitable for a diesel engine equipped with an exhaust gas aftertreatment device.

[Background technology]

Due to environmental problems, exhaust gas regulations around the world are becoming stricter year by year. Especially for exhaust gas from diesel engines, reduction of NOx and particulate matter (SPM) is urgently required. To reduce these emissions, diesel engines have traditionally included high-pressure injection, exhaust gas recirculation systems (EGR), oxidation catalysts, diesel particulate filters (DPF), or NOx storage and reduction catalysts. The introduction of mitigation measures is under consideration.

Among the exhaust gas reducing means, it is known that the life of the oxidation catalyst, the NOx storage reduction catalyst, and the DPF of the exhaust gas aftertreatment device is shortened depending on the composition of the lubricating oil used. For example, when a lubricating oil containing zinc dialkyldithiophosphate (hereinafter referred to as ZnDTP), which is effective as an antiwear agent or an antioxidant (peroxide decomposing agent), is used. Zinc forms oxides or phosphates during the combustion process and accumulates on the catalyst surface and in the filter, which may impair the purification performance of these exhaust gas aftertreatment devices. Therefore, it is desirable not to add ZnDTP to the engine lubricating oil equipped with the exhaust gas aftertreatment device as described above, or to keep the addition amount small even if it is used. In addition, in the case of metal-based detergents, the above-mentioned problems are likely to occur due to the deposition of sulfates and oxides as ash, as in the case of ZnDTP.

However, in diesel engines, especially in diesel engines equipped with EGR, a large amount of soot is mixed into the lubricating oil, so if the content of ZnDTP or metallic detergent in the lubricating oil is reduced, the valve train Etc. wear increase, biston cleanliness There is a concern about deterioration. Therefore, when the content of Zn DTP or a metal-based detergent is reduced, it is necessary to consider a new means for compensating for a decrease in the cleanliness and abrasion prevention due to the reduction. As a lubricating oil composition for an engine equipped with an exhaust gas post-treatment device, a diesel engine oil composition in which the amount of sulfated ash is suppressed to 0.7% by mass or less has been proposed (Japanese Patent Application Laid-Open No. 2000_256690). No.).

The present invention exhibits high anti-abrasion properties and high-temperature detergency even when the amount of ZnDTP or metal-based detergent is reduced, and has high anti-abrasion properties even under conditions where a large amount of soot is mixed. It is another object of the present invention to provide a low ash type diesel engine oil suitable for a diesel engine equipped with an exhaust gas aftertreatment device.

[Disclosure of the Invention]

The present inventors have conducted intensive studies for a diesel engine oil that can maintain wear resistance and high-temperature detergency even when the content of ZnDTP and a metal-based detergent is reduced, and as a result, ZnDTP, While reducing the amount of the metal-based detergent, a specific amount of a specific ashless dispersant and a specific phosphorus-containing ashless antiwear agent, or a specific amount of a fatty acid amide, can be added to mix in soot. The present inventors have also found that a lubricating oil composition exhibiting excellent anti-wear properties and high-temperature detergency can be obtained, and have completed the present invention.

The present invention relates to a base oil composed of mineral oil and / or synthetic oil containing (A) an imidized succinic acid-based ashless dispersant in a nitrogen concentration of 0.08 to 0.40 mass%, and (B) a metal-based detergent in terms of a metal element. 0.06 to 0.22 mass% in terms of amount, (C) zinc secondary alkyldithiophosphate in an amount of 0.04 to 0.08 mass% in terms of phosphorus element, and (D) phosphorus-containing ashless antiwear agent. An internal combustion engine containing 0.01 to 0.04% by mass in terms of a phosphorus element, and an amount of sulfated ash derived from a metal element in the composition of 0.3 to 1.0% by mass. Lubricating oil composition.

In addition, the present invention relates to a base oil composed of mineral oil and Z or synthetic oil, containing (A) an imidized succinic acid-based ashless dispersant in an amount of 0.08 to 0.40 mass% in terms of nitrogen element, and (B) a metal-based detergent. Is 0.06 to 0.22% by mass in terms of a metal element, and (C) 0.02 to 0.08% by mass of zinc secondary alkyldithiophosphate in terms of a phosphorus element. /. (D) Phosphorus-containing ashless antiwear agent in an amount of 0.01 to 0.04% by mass in terms of phosphorus element, (E) fatty acid Lubricating oil for internal combustion engines, characterized in that the composition contains 0.01 to 2.0% by mass of a sulfide and the amount of sulfated ash derived from a metal element in the composition is 0.3 to 1.0% by mass. Also found in oil compositions.

In the lubricating oil composition of the present invention, the component (B) is preferably an alkaline earth metal salicylate. The component (D) is preferably at least one compound selected from the group consisting of a phosphoric ester or an amine salt thereof, and a phosphite or an amine salt thereof. Further, the lubricating oil composition of the present invention is preferably used for a diesel engine equipped with an exhaust gas aftertreatment device. Hereinafter, the present invention will be described in detail.

The lubricating base oil in the present invention is not particularly limited, and any of a mineral base oil and a synthetic base oil may be used as long as it is generally used as a base oil of a lubricating oil composition. it can.

As the mineral base oil, specifically, a lubricating oil fraction obtained by atmospheric distillation and vacuum distillation of crude oil is subjected to solvent removal, solvent extraction, hydrocracking, solvent dewaxing, hydrorefining, 精製And refined by one or more treatments such as isomerization, and in particular, various base oils such as those that have been subjected to hydrocracking, hydrorefining, or wax isomerization. it can.

Specific examples of the synthetic base oil include alkylnaphthalene, alkylbenzene, polybutene or hydride thereof; poly-α-olefin such as 1-otaten oligomer and 1-decene oligomer or hydride thereof; ditridecyl glutarate Diesters such as dioctyl adipate, disodecyl adipate, ditridecyl adipate, and dioctyl sebacate; trimethylolpropane caprylate, trimethylol repronoperperanolegonate, pentaerythritol tonole _ Examples thereof include polyol esters such as 2-ethynolehexanoate, and pentaerythritol pelargonate, and mixtures thereof. Among them, preferred are poly- _α -olefins such as 1-octene oligomer and 1-decene oligomer, and hydrides thereof.

Lubricating base oils other than those using mineral oil base oils or synthetic base oils alone or as a mixture Alternatively, it may be a mixture of two or more mineral base oils or a mixture of two or more synthetic base oils. The mixing ratio of two or more base oils in the above mixture is not particularly limited, and can be arbitrarily selected. '

The total aromatic content of the lubricating base oil is not particularly limited, but is preferably 15% by mass or less, more preferably 13% by mass or less, and even more preferably 10% by mass or less. If the total aromatic content of the lubricating base oil exceeds 15% by mass, oxidation stability is poor, which is not preferable. On the other hand, if the total aromatic content is less than 2% by mass, the components (A) to (D) may not have sufficient solubility in the lubricating base oil, so that the The amount is preferably at least 2% by mass. The term “total aromatic content” as used herein means the content of an aromatic fraction measured in accordance with ASTM D 2549. Generally, the aromatic fraction includes alkylbenzene, alkylnaphthalene. , Anthracene, phenanthrene, their alkylated compounds, compounds in which four or more benzene rings are condensed, or compounds having heteroaromatics such as pyridines, quinolines, phenols, naphthols, etc. .

The kinematic viscosity of the lubricating base oil is not particularly limited, the kinematic viscosity at 100 ° C, is preferably 2m m ² / s or more, more preferably 3 mm ² / s or more, while its The kinematic viscosity is preferably 1 Omm ² / s or less, more preferably 8 mm ² Zs or less. By setting the kinematic viscosity of the lubricating base oil at 100 ° C to 2 mm ² Zs or more, the formation of an oil film is sufficient, the lubricating property is excellent, and the evaporation loss of the base oil under high-temperature conditions is further improved. Small compositions can be obtained. On the other hand, when the kinematic viscosity at 100 ° C. is 10 mm ² Zs or less, a fluid resistance is reduced, and a composition having a smaller friction resistance at a lubricating point can be obtained.

The (A) imidized succinic acid-based ashless dispersant in the lubricating oil composition for an internal combustion engine of the present invention is, for example, a monoimide represented by the following general formula (1) and a monoimide represented by the following general formula (2) Bisimide and those modified with an organic acid or boric acid are exemplified.

In the general formula (1) and (2), R 11 ² and 1 ^ ³ are each an individual polypeptide Buteyuru group, _m and _n are each an integer of individually 2-5.

The number average molecular weight of the polybutyr group represented by RR ² and R ³ is preferably 800 or more, more preferably 900 or more, and particularly preferably 150 or more, On the other hand, the number average molecular weight is preferably 350 or less, more preferably 250 or less. When the number average molecular weight is less than 800, cleanliness tends to decrease, and when the number average molecular weight exceeds 350, low temperature fluidity tends to decrease, which is not preferable. In order to obtain an excellent sludge control effect, m and n are preferably 3 or 4, respectively.

The polybutene group is obtained from polybutene obtained by polymerizing a mixture of 1-butene and isobutene or high-purity isobutene using an aluminum chloride-based or boron fluoride-based catalyst. And those from which chlorine has been sufficiently removed are particularly preferred.

The method for producing succinic acid imide is not particularly limited.For example, chlorinated polybutene having a number average molecular weight of 800 to 350, preferably polybutene from which chlorine and fluorine are sufficiently removed is mixed with maleic anhydride. It can be obtained by reacting polybutyrsuccinic acid obtained by reacting at 00 to 200 ° C. with polyamine. Examples of the polyamine include diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, and pentaethylenehexamine.

Examples of the method for producing boric acid-modified succinic acid imide include, for example, Japanese Patent Publication Nos. Sho 42-81013 and Sho 42-81014, and Japanese Unexamined Patent Publication No. Sho 51-52381. Gazette, and The method disclosed in Japanese Unexamined Patent Publication No. 51-140408 and the like can be mentioned. Specifically, for example, organic solvents such as alcohols, hexane, and xylene; polyamines and polybutenylsuccinic acids (anhydrides); boric acid, borate esters, and borate salts; It can be obtained by mixing a boron compound and subjecting it to heat treatment under appropriate conditions. The boron content of the boron-modified succinic acid imid thus obtained is usually 0.1 to 4.0% by mass.

The lower limit of the content of the component (A) in the present invention is 0.08% by mass, preferably 0.10% by mass, particularly preferably 0.1% by mass, based on the total amount of the composition. 2% by mass. On the other hand, the upper limit is 0.4% by mass, preferably 0.3% by mass, in terms of nitrogen element based on the total amount of the composition. When the content of the component (A) is less than 0.08% by mass, sufficient high-temperature detergency cannot be obtained. On the other hand, when the content exceeds 0.4% by mass, low-temperature fluidity deteriorates and the skin becomes poor.

The component (B) in the lubricating oil composition for an internal combustion engine of the present invention is a metal-based detergent. As the metal-based detergent, any metal-based detergent used for lubricating oils can be used. Specifically, for example, alkali metal sulfonate or alkaline earth metal sulfonate, alkali metal phenate or alkaline earth metal One or more kinds of alkaline metal or alkaline earth metal selected from metal phenate, alkali metal salicylate or alkaline earth metal salicylate, alkaline metal phosphonate or alkaline earth metal phosphonate, etc. Metal-based detergents;

Alkyli metal sulfonates or alkaline earth metal sulfonates include alkyl aromatic compounds obtained by sulfonating alkyl aromatic compounds having a molecular weight of 300 to 150, preferably 400 to 700. Metal salts of alkaline sulfonic acids or alkaline earth metal salts, especially salts of sodium, potassium, magnesium, calcium and the like, and magnesium salts and calcium salts are preferably used.

Specific examples of the alkyl aromatic sulfonic acid include so-called petroleum sulfonic acid and synthetic sulfonic acid. As the petroleum sulfonic acid, a sulfonated alkyl aromatic compound of a lubricating oil fraction of a mineral oil is generally used, for example, so-called mahoganic acid which is a by-product of white oil production. Synthetic sulfonic acids include, for example, by-products from the manufacturing plant for alkirbenzen, a raw material for detergents, and polio. A sulfonated alkylbenzene having a linear or branched alkyl group, which is obtained by alkylating lefin to benzene, or a sulfonated alkylnaphthalene such as dinonylnaphthalene is used. . As a sulfonating agent for sulfonating these alkyl aromatic compounds, fuming sulfuric acid or sulfuric anhydride is usually used.

Alkali metal phenates or alkaline earth metal phenates include alkyl phenols, anorec quinole phenol resulfides, alkali metal salts of alkyl phenols and Mannich reactants of alkyl phenols, especially alkaline metal earth salts. Salts such as sodium, potassium, magnesium, calcium and the like. Examples of the alkali metal phenate or the alkaline earth metal phenate include compounds represented by the following general formulas (3) to (5).

In the general formula (3), R ¹¹ represents a straight-chain or branched alkyl group having 4 to 30 carbon atoms, preferably 6 to 18 carbon atoms, and は¹ represents an alkali metal or an alkaline earth. metal indicates, [rho represents 1 or 2, when Micromax ¹ is an alkali metal, [rho is 1, when Micromax ¹ is an alkaline earth metal, [rho is 2.

In the general formulas (4) and (5), R ²² , R ¹³ , R ¹⁴ , R ¹⁵ and R ^{16 each} independently represent a straight chain having 4 to 30 carbon atoms, preferably 6 to 18 carbon atoms. Or a branched alkyl group; M ² and M ³ each independently represent an alkaline earth metal; and X represents 1 or 2.

Examples of the alkyl group represented by R ¹ i to R ¹⁶ include a butyl group and Methyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, pentadecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group Groups, henicosinole, docosinole, tricosyl, tetracosinole, pentacosinole, hexacosyl, heptacosyl, octacosyl, nonacosyl, and triacontyl groups. These may be straight-chain or branched. These may also be primary alkyl groups, secondary alkyl groups or tertiary alkyl groups.

The alkaline earth metal is preferably calcium or magnesium, and particularly preferably potassium hydroxide.

Examples of the alkaline metal salicylate or alkaline earth metal salicylate include alkali metal salts or alkaline earth metal salts of alkyl salicylic acid, particularly salts of sodium, potassium, magnesium, calcium and the like. Examples of the alkali metal salicylate or alkaline earth metal salicylate include a compound represented by the following general formula (6).

In the general formula (6), R ¹⁷ represents a linear or branched alkyl group having ⁴ to 30 carbon atoms, preferably 6 to 18 carbon atoms, and M ⁴ represents an alkali metal or an alkali earth metal. And q represents 1 or 2. When M ⁴ is an alkali metal, q is 1; and when M ⁴ is an alkaline earth metal, q is 2.

Specific examples of the alkyl group represented by R ¹⁷ include a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, a pendecyl group, a dodecyl group, a tridecyl group, and a tetradecyl group. Group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, henycosyl group, docosyl group, tricosinole group, tetracosinole group, pentacosyl group, hexacosyl group, heptacosyl group, octacosyl group, nonacosyl group And a triacontyl group. These may be straight-chain or branched. These may also be primary, secondary or tertiary alkyl groups. The alkaline earth metal is preferably calcium or magnesium, and particularly preferably potassium hydroxide.

Alkali metal sulfonate or alkaline earth metal sulfonate, alkaline metal phenate or alkaline earth metal phenate and alkali metal salicylate or alkaline earth metal salicylate are the above-mentioned alkyl aromatic sulfonic acid, alkyl phenol, Alkyl phenol sanolefied, Mannich reaction product of alkyl phenol, and alkyl salicylic acid, etc. directly into alkali metal or alkaline earth metal such as oxide or hydroxide of alkali metal or alkaline earth metal It can be obtained by reacting with a base.

In the lubricating oil composition of the present invention, an alkaline earth metal-based detergent is preferred. In the present invention, except for the neutral (normal salt) alkaline earth metal sulfonate, neutral (normal salt) alkaline earth metal phenate and neutral (normal salt) alkaline earth metal salicylate obtained as described above Also, neutral alkaline earth metal sulfonate, neutral alkaline earth metal phenate or neutral alkaline earth metal salicylate and excess alkaline earth metal salt or alkaline earth metal base are converted into water. Basic alkaline earth metal sulfonate, basic alkaline earth metal phenate and basic alkaline earth metal salicylate, or neutral alkaline earth metal sulfonate, obtained by heating in the presence of Reacting alkaline earth metal hydroxide with carbon dioxide gas or boric acid in the presence of alkaline earth metal phenate or neutral alkaline earth metal salicylate The resulting overbased (ultrabasic) alkaline earth metal sulfonates, overbased (ultrabasic) alkaline earth metal funates and overbased (ultrabasic) alkaline earth metal salicylates are also preferably used. be able to.

In the present invention, the above-mentioned alkali metal salts, neutral alkaline earth metal salts, basic alkaline earth metal salts, overbased (ultrabasic) alkaline earth metal salts, and mixtures thereof are used. Can be. The alkali metal detergent or alkaline earth metal detergent used in the present invention generally has a total base number of 0 to 50 O mg KO HZ g. The total base number is preferably 0 to 35 Omg KOH / g, and more preferably 140 to 20 Omg KO, in order to obtain anti-wear performance under soot contamination. HZ g. The total base number is calculated by JI SK 250 1 (1992) means the total base number by the perchloric acid method measured in accordance with 7. of “Petroleum products and lubricating oils—Testing methods for neutralization number”.

Metal detergents are usually commercially available in a diluted state with a light lubricating base oil or the like, and are available, but generally have a metal content of 1.0 to 20% by mass. preferably used ones of from 2.0 to 1 6 mass ^_0/0.

In the present invention, the lower limit of the content of the component (B) is 0.06% by mass, preferably 0.08% by mass in terms of a metal element based on the total amount of the composition. On the other hand, the upper limit of the content of the component (B) is 0.22% by mass, preferably 0.20% by mass, more preferably 0.18% by mass in terms of a metal element based on the total amount of the composition. %, Particularly preferably 0.14% by mass. When the content of the component (B) is less than 0.06% by mass, it is difficult to maintain the anti-wear property. On the other hand, when the content of the component (B) exceeds 0.22% by mass, It is not preferable because the amount of ash deposited on the treatment equipment may increase. In the present invention, it is particularly preferable to use an alkaline earth metal salicylate from the viewpoint of maintaining high-temperature cleanliness and abrasion resistance.

The component (C) in the lubricating oil composition for an internal combustion engine of the present invention is zinc secondary alkyl dithiophosphate. Specific examples of the zinc secondary alkyldithiophosphate include compounds represented by the following general formula (7).

In the general formula (7), R ²¹ , R ²² , R ²³ , and R ²⁴ each independently represent a secondary alkyl group having 3 to 20 carbon atoms. If the alkyl group has less than 3 carbon atoms, the abrasion resistance and oxidative stability are inferior. On the other hand, if the number of carbon atoms exceeds 20, the abrasion resistance and the oxidative stability are similarly unfavorable.

The secondary alkyl group is represented by the following general formula (8).

In the general formula (8), R ²⁵ and R ²⁶ each independently have 1 to 18 carbon atoms. And a linear or branched alkyl group having a total carbon number of 2 to 19 of R ²⁵ and R ²⁶ .

Specific examples of the alkyl group represented by R ²⁵ and R ²⁶ include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, and a nonyl group. And an alkyl group such as a decyl group, a decyl group, a decyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, and a hexadecyl group (the alkyl group may be linear or branched).

Preferred examples of the secondary alkyl group include an isopropyl group, a 1-methylpropyl group, and a 1,3-dimethylbutyl group. Particularly preferred is a 1,3-dimethylbutyl group.

The above zinc secondary alkyldithiophosphate may be used alone or in combination of two or more.

In the present invention, the lower limit of the content of the component (C) is 0.04% by mass, preferably 0.05% by mass, in terms of the phosphorus element concentration based on the total amount of the composition. On the other hand, the upper limit of the content is 0.08% by mass, preferably 0.07% by mass, in terms of the phosphorus element concentration based on the total amount of the composition. When the content of the component (C) is less than 0.04% by mass, it is difficult to maintain the initial wear preventing property and the anti-wear property, while the content of the component (C) exceeds 0.08% by mass. In such a case, the amount of ash deposited on the exhaust gas aftertreatment device may increase, and the high-temperature cleaning performance deteriorates.

When the component (C) described above is used in combination with the component (E) described below, the content thereof can be reduced. In this case, the lower limit of the content of the component (C) is 0.02% by mass, preferably 0.025% by mass in terms of the phosphorus element concentration based on the total amount of the composition, while the upper limit is 0%. 0.08% by mass or less, 0.05% by mass or less, 0.04% by mass or less, and 0.035% by mass or less A low ash composition can be obtained.

The component (D) in the lubricating oil composition for an internal combustion engine of the present invention is a phosphorus-containing ashless wear inhibitor. Specific examples of the phosphorus-containing ashless wear inhibitor include phosphoric esters having 2 to 30 carbon atoms, preferably 6 to 20 hydrocarbon groups, or amine salts thereof, and 2 to 30 carbon atoms, preferably Phosphorous ester having 6 to 20 hydrocarbon groups And their amine salts. These can be used alone or as a mixture.

Examples of the hydrocarbon group having 2 to 30 carbon atoms include an alkyl group, a cycloalkyl group, an alkylcycloalkyl group, an alkenyl group, an aryl group, an alkylaryl group, and an arylalkyl group.

Specific examples of the alkyl group include an ethyl group, a propyl group, a butyl group, a benzyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, a benzyl group, a dodecyl group, a tridecyl group, Examples thereof include alkyl groups such as a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, and an octadecyl group (the alkyl groups may be linear or branched).

Specific examples of the cycloalkyl group include cycloalkyl groups having 5 to 7 carbon atoms, such as a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group.

Specific examples of the above alkylcycloalkyl group include a methylcyclopentyl group, a dimethynolecyclopentynole group, a methinoleethynolecyclopentyl / re group, a ethynoleic pentopenole group, a methynolecyclohexyl group, a dimethylenocyclohexyl group, and a methynolele. Alkylcycloalkyl groups having 6 to 11 carbon atoms such as tylcyclohexynole group, getylcyclohexynole group, methylcycloheptyl group, dimethynolecycloheptinol group, methynoleethynolecycloheptinol group, and jeti / resin heptyl group. (The substitution positions of these alkyl groups with cycloalkyl groups are arbitrary). Specific examples of the alkenyl group include alkenyl groups such as a butenyl group, a pentenyl group, a hexenyl group, a heptyl group, an otatyl group, a nonenyl group, a decenyl group, a pentadecenyl group, a dodecenyl group, and an octadecenyl group. The group may be linear or branched, and the position of the double bond is also arbitrary.).

Specific examples of the aryl group include aryl groups such as a phenyl group and a naphthyl group.

Specific examples of the alkylaryl group include a trinole group, a xylyl group, an ethylphenyl group, a propynolephenyl group, a butylphenyl group, a pentylphenyl group, And alkenyl groups having 7 to 12 carbon atoms, such as hexylphenyl group (these alkyl groups may be linear or branched, and the position of substitution with the aryl group is arbitrary) Can be mentioned.

Specific examples of the arylalkyl group include those having 7 to 12 carbon atoms, such as a benzyl group, a phenylethyl group, a phenylpropyl group, a phenylbutyl group, a phenylpentyl group, and a phenylhexyl group. And arylalkyl groups (these alkyl groups may be linear or branched).

Specific examples of the (sub) phosphoric acid ester preferable as the component (D) in the present invention include monopropyl phosphate, monobutyl phosphate, monopentyl phosphate, monohexynole phosphate, monopeptinole phosphate, and monooctyl. Monoalkyl phosphates such as phosphate (the alkyl group may be linear or branched); Mono (alkyl) aryl esters of phosphate such as monophenyl phosphate, monocresyl phosphate; dipropyl Phosphoric acid dianolekyl esters such as phosphate, dibutyl phosphate, dipentinolephosphate, dihexynolephosphate, dipeptinolephosphate, and dioctynolephosphate (anorexyl group may be linear or May be branched); diphenylphospho Di (alkyl) aryl esters such as tributyl phosphate and dicresyl phosphate; trialkyl phosphates such as tripropyl phosphate, tributyl phosphate, tripentyl phosphate, trihexyl phosphate, tripeptyl phosphate and trioctyl phosphate. Ester (alkyl group may be linear or branched); tri (alkyl) aryl esters such as triphenyl phosphate and tricresyl phosphate; monopropyl phosphate, monobutyl phosphate, monopentyl phosphate Phosphite monoalkyl esters such as monohexyl phosphite, monopeptinole phosphite, and monooctyl phosphite (the alkyl group may be linear or branched); monophenyl phosphite Phosphite mono (alkyl) aryl esters such as dimethyl phosphite and monocresyl phosphite; dipropyl phosphite, dibutyl phosphite, dipentinole phosphite, dihexynole phosphite, dibutyl phosphite Dialkyl phosphites such as di- and octyl phosphites (alkyl groups may be linear or branched); diphenyl phosphite, dicresyl Di (alkyl) aryl esters such as phosphite; tripropyl phosphite, tributyl phosphite, tripentyl phosphite, trihexyl phosphite, triptyl phosphite, trioctyl phosphite Trialkyl esters (alkyl groups may be linear or branched); tri (alkyl) aryl esters of phosphites such as triphenylphosphite and tricresylphosphite; and These mixtures can be exemplified.

Examples of the amine salts of the above-mentioned (sub) phosphoric acid esters include, for example, ammonia and phosphoric acid monoester, phosphoric acid monoester, phosphorous acid diester, etc. Salts obtained by reacting a nitrogen-containing compound such as an amine compound containing only a hydrocarbon group or a hydroxyl group-containing hydrocarbon group in the molecule thereof to neutralize a part or all of the remaining acidic hydrogen can be exemplified. Specific examples of the nitrogen compound include ammonia; monomethylamine, monoethylamine, monopropylamine, monobutynoleamine, monopentylamine, monohexylamine, monoheptylamine, monooctylamine, monostearyl. Luamine, monooleylamine, monopropenylamine, monobutenylamine, monooctylamine, monooctadedecenylamine, dimethylamine, methylethylamine, getylamine, methinolepropynoleamine, ethylethylpropylamine Alkyl or alkenylamine such as dipropylamine, methylbutylamine, ethylbutylamine, propylbutylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, etc. Or a alkenyl group may be linear or branched); monomethanolamine, monoethanolamine, monopropanolamine, monobutanolamine, monopentanoleamine, monohexanolenoamine, monoheptanol Noreamine, Monooctanolamine, Monononanolamine, Dimethanolamine, Methanolethanolamine, Diethanolanolamine, Methanolpropanolamine, Ethanolpropanolamine, Dipropanolamine, Methanolbutanolamine, Ethanol-Lbutanolamine Min, propanol butanolamine, dibutanolamine, dipentanolamine, dihexanolamine, diheptanolamine, dioctanol Alkanolamines such as tanolamine (the alkanol groups may be linear or branched); and mixtures thereof.

In the present invention, specifically, trifluorenyl phosphite or oleylamine salt of stearylhydrogen phosphite is particularly preferably used because it can maintain excellent antiwear performance and high-temperature cleaning performance.

One or more of these (D) components can be arbitrarily compounded. The lower limit of the content of the component (D) in the lubricating oil composition of the present invention is 0.01% by mass, preferably 0.015% by mass, in terms of phosphorus element based on the total amount of the composition. On the other hand, the upper limit of the content is 0.0 in terms of phosphorus element based on the total amount of the composition.

The amount is 4% by mass, preferably 0.035% by mass. (D) The content of the component is 0.

If the content is less than 0.1% by mass, it is difficult to maintain the initial wear-preventing property and the wear-preventing property. Respectively, which is not preferred.

The component (E) in the lubricating oil composition for an internal combustion engine of the present invention is a fatty acid amide. Specific examples of the fatty acid in the fatty acid amide include linear fatty acids and branched fatty acids, and saturated fatty acids. Although the unsaturated fatty acid may be used, the alkyl group or alkenyl group has 6 to 30 carbon atoms, preferably 9 to 24, more preferably 12 to 2 carbon atoms.

It is 0. If the fatty acid has less than 6 carbon atoms in the alkyl or alkenyl group, the solubility will be poor, and if it exceeds 30, the anti-wear properties will be reduced, which is not preferred.

Specific examples of the fatty acid include heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, pendecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, and nonadecane Saturated fatty acids such as acid, icosanoic acid, henycosanoic acid, docosanoic acid, trichosanoic acid, tetracosanoic acid, pentacosanoic acid, hexacosanoic acid, heptacosanoic acid, octacosanoic acid, nonacosanoic acid, and triacontyl group. May be branched); heptenoic acid, otatenic acid, nonenoic acid, decenoic acid, pendecenoic acid, dodecenoic acid, tridecenoic acid, tetradecenoic acid, pentadecenoic acid, hexadecenenoic acid, heptadecenoic acid, octadedecenoic acid, nonadecenenoic acid, Icosenoic acid, f Ikosen acid - Unsaturated fatty acids such as docosenoic acid, tricosenoic acid, tetracosenoic acid, pentacosenoic acid, hexacosenoic acid, heptacosenoic acid, octacosenoic acid, nonacosenic acid, and triaconthenic acid (these unsaturated fatty acids may be linear or branched; The position of the double bond is also arbitrary.).

As the fatty acid amide of the component (E), specifically, for example, the above fatty acid or its oxychloride contains only ammonia or a hydrocarbon group having 1 to 20 carbon atoms or a hydroxyl group-containing hydrocarbon group in a molecule. And the like obtained by reacting a nitrogen compound such as an amine compound.

Specific examples of the nitrogen compound include ammonia; monomethylamine, monoethylamine, monopropylamine, monobutylamine, monopentylamine, monohexylamine, monoheptylamine, monooctylamine, dimethylamine, methylamine, and the like. Noreethylamine, getylamine, methylpropylamine, ethylpropylamine, dipropylamine, methylbutylamine, ethylbutylamine, pulpuchile / reamine, dibutylamine, dipentinoleamine, dihexylamine, diheptylamine, dioctylamine, etc. Alkylamine (alkyl group may be linear or branched); monomethanolamine, monoethanolamine, monopropanolamine, monobutanolamine, monopentanolamine , Monohexanolamine, monoheptanolamine, monooctanolamine, monononanolamine, dimethanolamine, methanolethanolamine, diethanolanolamine, methanolololepropanolamine, ethanolololepropanolamine, dipropanolamine, Alkanolamines such as methanolbutanolamine, ethanolbutanolamine, propanolbutanolamine, dibutanolamine, dipentanolamine, dihexanolamine, diheptanolamine, dioctanolamine, etc. Linear or branched); and mixtures thereof.

In the present invention, specifically, amide stearic acid amide and the like are particularly preferably used because they are excellent in initial wear-preventing property and excellent maintenance performance of wear-preventing property.

By using the component (E) in the lubricating oil composition for an internal combustion engine of the present invention, the content of the component (C) can be reduced. (E) When the component is contained, The lower limit is 0.01% by mass, preferably 0.05% by mass, based on the total amount of the composition, while the upper limit of the content is 2.0% by mass, based on the total amount of the composition. It is preferably 1.0% by mass. When the content of the component (E) is less than 0.01% by mass, it is difficult to maintain the anti-wear property. On the other hand, when the content of the component (E) exceeds 2.0% by mass, Each is not preferable because the stability is deteriorated.

The lubricating oil composition for an internal combustion engine of the present invention has an amount of sulfated ash derived from a metal element in the range of 0.3 to 1.0% by mass. The lower limit of the sulfated ash content is preferably 0.4% by mass, more preferably 0.45% by mass, and still more preferably 0.50% by mass. On the other hand, the upper limit of the sulfated ash content is preferably 0.8% by mass, more preferably 0.65% by mass, and particularly preferably 0.6% by mass. If the lower limit of the sulfated ash content is less than 0.3% by mass, it is difficult to maintain the anti-wear performance as described above, while if the sulfated ash content exceeds 1.0% by mass, However, deposition of ash on the exhaust gas after-treatment device, particularly in DPF, is not preferable because it may cause undesired effects such as clogging by ash.

In the lubricating oil composition of the present invention, an ashless dispersant other than the component (A), an antiwear agent other than the components (C) and (D), if necessary, as long as the object of the present invention is not impaired, E) Friction modifiers, antioxidants, antioxidants, demulsifiers, metal deactivators, defoamers, etc. other than the components can be added as appropriate.

The ashless dispersant other than the component (A) includes benzylamine having at least one alkyl group or alkenyl group having 40 to 400 carbon atoms in the molecule and a derivative thereof, and an alkyl group or alkenyl group having 40 to 400 carbon atoms in the molecule. And at least one polyamine and its derivatives.

Examples of the antiwear agent other than the components (C) and (D) include, for example, thiophosphoric acid esters containing 1 to 4 sulfur atoms in the molecule, and thiophosphorus acid esters containing 1 to 3 sulfur atoms in the molecule. Phosphoric esters and their amine salts, disulfides, sulfurized olefins, dithiocarbamates, sulfurated compounds such as sulfurized oils and the like, and the like. In addition, although zinc primary dialkyldithiophosphate and zinc diaryldithiophosphate may be contained, in the present invention, it is preferable that zinc dithiophosphate comprises only the component (C). Examples of the friction modifier other than the component (E) include molybdenum dithiolbamate, molybdenum dithiophosphate, a fatty acid ester having a hydrocarbon group having 6 to 30 carbon atoms, and an aliphatic amine.

Examples of the antioxidant include various funols, amines, and sulfur compounds.

Examples of the antioxidant include alkenyl succinates and polyhydric alcohol esters.

Examples of the demulsifier include non-ionic surfactants such as polyoxyethylene alkyl ethers, polyoxyethylene alkyl / naphthyl ethers, and polyalkylene dalicol-based nonionic surfactants such as polyoxyethylene alkyl naphthyl ether. Examples of the metal deactivator include benzotriazole-based, benzimidazole-based, benzothiazole-based, and thiadiazole-based compounds.

Antifoaming agents include, for example, dimethylpolysiloxane, and polyatalylate.

When these additives are contained in the lubricating oil composition for an internal combustion engine of the present invention, the content thereof is based on the total amount of the composition, and the ashless dispersant other than the component (A), the component (C) and the component (D) are used. ) Component, friction modifier, corrosion inhibitor, antioxidant, and demulsifier other than component (E), respectively, 0.01 to 5% by mass, 0.0 for metal deactivator. The amount is usually selected from the range of 0.5 to 1% by mass, and the range of 0.05 to 1% by mass for the antifoaming agent.

[Best Mode for Carrying Out the Invention]

Hereinafter, 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.

(Examples 1 to 7 and Comparative Examples 1 to 6)

According to the compositions shown in Tables 1 and 2, a lubricating oil composition for an internal combustion engine of the present invention (Examples 1 to 7) and a lubricating oil composition for an internal combustion engine for comparison (Comparative Examples 1 to 6) were prepared. And it evaluated by the performance evaluation test shown below. Tables 1 and 2 show the evaluation test results. (1) High-speed four-ball test

1) When the initial lubricating oil composition (new oil) is used

3% by mass of carbon black was blended with each of the obtained lubricating oil compositions, and the mixture was stirred and dispersed with a homogenizer at 25,000 rpm for 10 minutes. Using each of the obtained test oils, the test was carried out at 80 ° C, 1800 rpm, 30 kg, 30 minutes in accordance with ASTM D 4 17 _ 8 2 (Shell high-speed four-ball wear test). The wear scar diameter was measured.

2) When using deteriorated lubricating oil composition

Based on the oxidation stability test for lubricating oil for internal combustion engines (Indiana Stirring Oxidation Test JIS K25 14, hereinafter abbreviated as IS OT), each lubricating oil composition is forcibly deteriorated at 165.5 ° C for 24 hours After that, each deteriorated oil was blended with 3% by mass of carbon black in the same manner as above to prepare each deteriorated test oil. Then, a wear test was performed in the same manner as described above, and the wear scar diameter was measured.

(2) Hot tube test

The high-temperature detergency of each lubricating oil composition was evaluated by a Komatsu Manufacturing hot tube test “HT-201”. The test was carried out by heating a soft glass tube to 290 ° C with a pure aluminum burning block and feeding 0.3 ml 1 Zhr and 1 Om 1 Z air into the tube for 16 hours continuously. After the test was completed, the tubes were washed with petroleum ether and the high-temperature cleanliness was evaluated from the stain on the inner wall. The score was 10 points for colorless and transparent (no stain) and 0 points for black and opaque, and the evaluation was performed at intervals of 0.5 with reference to a standard tube prepared in advance at intervals of 1 interval. 2. If the rating is 6 or more at 90 ° C, the lubricant is judged to be excellent in cleanliness.

table 1

s3

O

Table 2

The footnotes in Tables 1 and 2 indicate the following.

1) Hydrorefined mineral oil

(Kinematic viscosity 4mm ² Zs (@ 100 ° C), viscosity index O)

2) Borated bispolybutyrsuccinic acid imide

(Bis type, number average molecular weight of polybutenyl group 1300, nitrogen content 1.6 mass%, boron content 0.5 mass%)

3) Overbased calcium salicylate containing calcium carbonate

(Total base number: 166, calcium content: 5.8 mass%, sulfated ash content: 19.7 mass ° / ₀ )

4) Overbased calcium sulfonate containing calcium carbonate

(Total base number: 320, calcium content 12.5 mass%, sulfated ash content 42.5 mass%)

5) Calcium carbonate-containing overbased calcium funate

(Total base number: 250, calcium content 9.25 mass%, sulfated ash content 31.5 mass%)

6) Zinc dialkyldithiophosphate

(Zinc content 7.8 mass ^_0/0, the phosphorus content of 7.2 mass%, alkyl group: 1,3 dimethyl Chinorebuchiru group)

7) triphenyl Phi preparative (phosphorus content 3.0 mass ^_0/0)

8) Stearyl hydrogen phosphite oleylamine salt

(2.5% by mass of phosphorus, 0.35% by mass of nitrogen)

9) isostearyl Atsushi de phosphate (phosphorus content 6.2 mass ^_0/0)

0) Oleic acid amide (Iodine value 80-90)

1) Phenol antioxidant, amine antioxidant, polymethacrylate type viscosity index improver

As is clear from the results in Tables 1 and 2, the lubricating oil compositions for internal combustion engines of the present invention (Examples 1 to 7) show excellent wear prevention performance and high-temperature cleaning performance while having low ash content. The anti-wear properties show high anti-wear performance with little change from the initial value even after the lubricant has deteriorated.

On the other hand, as seen in Comparative Examples 1 and 2, when the content of the component (B) is too small (less than the range specified in the present invention), the wear prevention performance of the deteriorated lubricating oil decreases. I do. As seen from Comparative Example 3, when the content of the component (A) is too small (less than the range specified in the present invention), sufficient high-temperature cleaning performance cannot be obtained. When the component (D) or the component (C) is not contained as shown in Comparative Examples 4 and 5, respectively, or when the content of the component (C) is too small as seen in Comparative Example 6 ( In the case where it is less than the range specified in the present invention), sufficient wear prevention performance cannot be obtained.

[Industrial applicability]

INDUSTRIAL APPLICABILITY The lubricating oil composition for an internal combustion engine of the present invention has excellent anti-wear properties and high-temperature detergency while having a low ash content, and in particular, has excellent anti-wear properties at the initial stage and after deterioration with soot contamination. Therefore, the lubricating oil composition for an internal combustion engine of the present invention can be particularly preferably used for a diesel engine equipped with an exhaust gas post-treatment device such as an EGR, an oxidation catalyst, a NOX storage reduction catalyst, and a DPF. It can also be preferably used for lubricating oils for gasoline engines such as marine diesel engines, gas engines, motorcycles and automobiles.

Claims

The scope of the claims

1. To base oil consisting of mineral oil and / or synthetic oil: (A) imidic succinic ashless dispersant 0.08 to 0.40 mass% in terms of nitrogen element, (B) metal detergent 0.06 to 0.22% by mass in terms of element, (C) Secondary alkyldithiophosphate 0.04 to 0.08% by mass in terms of phosphorus element, (D) Phosphorus-free ashless Wear prevention 0.1 to 0.04 mass% in terms of phosphorus element, and the amount of sulfated ash derived from the metal element in the composition is 0.3 to 1.0 mass%. Lubricating oil composition for internal combustion engines.

2. The base oil consisting of mineral oil and Z or synthetic oil contains (A) imidized succinic acid-based ashless dispersant in an amount of 0.08 to 0.40 mass% in terms of nitrogen element. /. (B) 0.06 to 0.22% by mass of metallic detergent in terms of metal element, and (C) 0.02 to 0.2% of zinc secondary alkyldithiophosphate in terms of phosphorous element. 08% by mass, (D) Phosphorus-containing ashless antiwear agent in 0.01 to 0.04% by mass in terms of phosphorus element, and (E) Fatty acid amide in 0.01 to 2.0% by mass A lubricating oil composition for an internal combustion engine, wherein the amount of sulfated ash derived from a metal element in the composition is from 0.3 to 1.0% by mass.

3. The lubricating oil composition for an internal combustion engine according to claim 1, wherein the component (B) is a salicylate of an alkaline earth metal.

4. The component according to claim 1, wherein the component (D) is at least one compound selected from the group consisting of a phosphate ester or an amine salt thereof, and a phosphite ester or an amine salt thereof. Or the lubricating oil composition for an internal combustion engine according to paragraph 2.

5. The lubricating oil composition for an internal combustion engine according to claim 1, which is used for a diesel engine equipped with an exhaust gas post-treatment device.