WO2004111162A1

WO2004111162A1 - Lubricant composition for internal combustion engine

Info

Publication number: WO2004111162A1
Application number: PCT/JP2004/007337
Authority: WO
Inventors: Kazuhiro Yagishita
Original assignee: Nippon Oil Corporation
Priority date: 2003-06-11
Filing date: 2004-05-21
Publication date: 2004-12-23
Also published as: JP2005002215A

Abstract

A lubricant composition for internal combustion engines, especially a low phosphorus, low sulfur lubricant composition for internal combustion engines is disclosed which is excellent in wear resistance and extreme-pressure characteristics. The lubricant composition for internal combustion engines contains, in the lubricant base oil, (A) at least one substance selected from specific phosphonates and salts thereof and (B) a zinc dithiophosphate having a secondary alkyl group.

Description

Lubricating oil composition for internal combustion engines

[Technical field]

The present invention relates to a lubricating oil composition for an internal combustion engine, and more particularly, to a low phosphorus, low sulfur type lubricating oil composition for an internal combustion engine having excellent wear resistance. Light

[Background technology]

Lubricating oil is used in internal combustion engines and automatic transmissions to facilitate their operation. In particular, lubricating oil (engine oil) for internal combustion engines is used to improve the performance, output, and operating conditions of internal combustion engines. Due to the severeness of the oil, high performance is required, and from the viewpoint of recent environmental problems, improvement of long drainability to extend the oil renewal interval is required. Therefore, in order to satisfy such required performance, various additives such as antiwear agents, metal detergents, ashless dispersants, and antioxidants are blended in conventional engine oils to improve their performance.

Conventionally, in the field of lubricating oils, especially in the field of lubricating oils for internal combustion engines, zinc dialkyldithiophosphate (ZDTP), an anti-wear and anti-oxidant, has been used as an almost essential additive. In response to recent environmental issues, the need to mitigate the effects on exhaust gas catalysts and DPFs (Diesel Particulate Filters), such as three-way catalysts, oxidation catalysts, and NOX storage reduction catalysts, installed in internal combustion engines, There is a strong demand for further reduction of sulfur, phosphorus and ash of lubricating oil. In particular, for gasoline engine oil, the next ILSACGF-4 standard calls for lowering the phosphorus content to 0.08% by mass or less for compatibility with exhaust gas catalysts, and further reducing phosphorus (for example, studies are ongoing. ILSACGF-5 standard (draft): Phosphorus content 0.05% by mass or less).

Conventional low phosphorus oils or phosphorus-free oils in which zinc dithiophosphate is reduced or not used are disclosed in, for example, Patent Documents 1 to 10 below. ~ 14. (Patent Document 1) JP-A-62-153691

(Patent Document 2) Japanese Patent Application Publication No. Hei 11-50910

(Patent Document 3) Japanese Patent Application Laid-Open No. 6-4-1568

(Patent Document 4) JP-A-63-304095

(Patent Document 5) JP-A-63-3-4096

(Patent Document 6) JP-A-52-704

(Patent Document 7) Japanese Patent Application Laid-Open No. 62-243692

(Patent Document 8) JP-T-62-5011917

(Patent Document 9) JP-T-62-5011572

(Patent Document 10) Japanese Patent Application Laid-Open No. 2000-1 63862

(Patent Document 11) Japanese Patent Application Laid-Open No. H8-488989

(Patent Document 1 2) Japanese Patent Application Laid-Open No. H8-2 53782

(Patent Document 13) JP-A-9-111275

(Patent Document 14) JP-A-2000-256690 However, in these conventional low-phosphorus oils or non-phosphorus-free oils, the wear-preventing performance is maintained by blending a sulfur-containing compound instead of zinc dithiophosphate. It increases the sulfur content of the composition, which has an adverse effect on exhaust gas aftertreatment equipment, ie, purification of exhaust gas from oxidation catalysts, three-way catalysts, NOx absorption reduction catalysts, etc. The problem of catalyst poisoning due to sulfur, such as catalysts, DPFs, or a system combining the above exhaust gas purifying catalyst and DPF, especially an exhaust gas treatment system combining an oxidation catalyst and DPF or a NOx storage reduction catalyst and DPF. Or, the problem of clogging of DPF has not been solved yet, and the oxidation stability, base number maintenance performance, cleanability, etc. of the lubricating oil will be significantly deteriorated.

Therefore, it is extremely difficult to simultaneously reduce the phosphorus content, the sulfur content, and the ash content of lubricating oil, and there has been a demand for a solution.

The present invention has been made in view of the above circumstances, and provides a lubricating oil composition for an internal combustion engine having extremely excellent wear resistance even when zinc dithiophosphate is reduced. It is intended to provide an engine lubricating oil. [Disclosure of the Invention]

The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, by using a specific phosphorus compound and a specific zinc dithiophosphate together, they are more synergistically resistant than when each is used alone. The present inventors have found that it is possible to improve the wear properties and to achieve low phosphorus and low sulfur in lubricating oil for internal combustion engines, and have completed the present invention.

That is, the present invention provides a lubricating base oil comprising at least one compound selected from the group consisting of (A) a phosphorus compound represented by the general formula (1) and a salt thereof, and (B) a secondary monoalkyl group. A lubricating oil composition for an internal combustion engine, characterized in that the lubricating oil composition contains zinc dithiophosphate.

(1)

(In the general formula (1) may contain a hydrocarbon group (the nitrogen and Z or oxygen), ₂ Oyobi 1 ₃ are each independently hydrogen or carbon atoms from 1 to 3 0 of hydrocarbon group ( Nitrogen and may contain Z or oxygen).)

Further, in the present invention, the lubricating base oil contains at least one kind selected from the above-mentioned component (A) and zinc zinc dithiophosphate, and the sulfur content of the composition is 0.1% based on the total amount of the composition. Low-sulfur, low-sulfur lubricating an internal combustion engine using a fuel having a sulfur content of 50 mass ppm or less with a lubricating oil composition of 3 mass% or less and a phosphorus content of 0.08 mass% or less. In the phosphorus engine system. Hereinafter, the present invention will be described in detail.

The lubricating base oil in the lubricating oil 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.

As a mineral base oil, specifically, lubricating oil fractions obtained by depressurizing distillation of atmospheric residual oil obtained by atmospheric distillation of crude oil are subjected to solvent removal, solvent extraction, and hydrocracking. , Purified by one or more treatments such as solvent dewaxing, hydrorefining, etc. Examples include mineralized mineral oils, lubricating base oils produced by a method of isomerizing GTL WAX (gas to liquid wax) produced by the Fischer-Tropsch process, and the like.

The percentage of mineral base oil is not particularly limited, but is preferably 5 or less, more preferably 3 or less, and further preferably 2 or less. Moreover,% C _A may be 0, but it is preferable that in view of the solubility of additives is 0. 4 or more, and more preferably 1 or more.

In addition, the above-mentioned% 〇8 indicates the percentage of the number of aromatic carbons to the total number of carbons obtained by the method specified in ASTM D3238_85.

The sulfur content in the mineral base oil is not particularly limited, but is preferably 0.05% by mass or less, more preferably 0.01% by mass or less, and 0.005% by mass or less. It is particularly preferred that the content be 1% by mass or less. By reducing the sulfur content of the mineral base oil, a low-sulfur lubricating oil composition having more excellent long drain properties can be obtained.

Specific examples of the synthetic base oil include polybutene or a hydride thereof; 1-octene oligomer, poly- _α -olefin such as 1-decene oligomer or a hydride thereof; ditridecyl glutarate, and di-2-ethyl. Diesters such as hexyl adipate, diisodecyl adipate, ditridecyl adipate, and di-2-hexyl hexyl sebacate; trimethylolpropane caprylate, trimethylol propane perperanolegonate, and pentaerythritol 1-2-ethyl Polyester esters such as hexanoate and pentaerythritol pelargonate; copolymers of dicarboxylic acids such as dibutyl maleate and α-olefins having 2 to 30 carbon atoms, alkylnaphthalene, alkylbenzene, and fragrance Aromatic synthetic oils such as aromatic esters or Mixtures of these can be exemplified.

In the present invention, as the lubricating base oil, a mineral base oil, a synthetic base oil, or an arbitrary mixture of two or more kinds of lubricating oils selected from these can be used. Examples thereof include one or more mineral base oils, one or more synthetic base oils, and a mixed oil of one or more mineral base oils and one or more synthetic base oils.

The kinematic viscosity of the lubricating base oil is not particularly limited, but its kinematic viscosity at 100 ° C is preferably 20 mm ² / s or less, more preferably 10 mm ² / s or less. is there. On the other hand, the kinematic viscosity is preferably 1 mm ² / s or more, more preferably Znim ² / s or more. If the kinematic viscosity of the lubricating base oil at 100 ° C exceeds 20 mm ² / s, the low-temperature viscosity characteristics deteriorate, while if the kinematic viscosity is less than 1 mm ² / s, the lubricating point Insufficient lubrication due to insufficient formation of an oil film at the same time, and evaporation loss of the lubricating base oil increases, which is not preferable.

The evaporation loss of the lubricating base oil is preferably 20% by mass or less, more preferably 16% by mass or less, particularly preferably 10% by mass or less, in terms of NOACK evaporation amount. preferable. When the NOACK evaporation amount of the lubricating base oil exceeds 20% by mass, not only the lubricating oil evaporation loss is large, but also the sulfur compounds, phosphorus compounds, or metals in the composition are discharged together with the lubricating base oil in the exhaust gas. It is not preferable because it may accumulate in the purification device and not only increases the oil consumption but also adversely affects the exhaust gas purification performance. Here, the NO ACK evaporation amount is a measurement of 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 is preferably 80 or more, more preferably 100 or more, and most preferably 100 or more so as to obtain excellent viscosity characteristics from low to high temperatures. Is 1 20 or more. The upper limit of the viscosity index is not particularly limited.Normal paraffin, slack wax, GTL wax, or the like, or about 135 to 180 such as isoparaffinic mineral oil obtained by isomerizing these, or complex ester base oil Approximately 150 to 250 oils such as and HV I-PAO base oils can also be used. If the viscosity index of the lubricating base oil is less than 80, the low-temperature viscosity characteristics deteriorate, which is not preferable. The component (A) in the lubricating oil composition of the present invention is at least one compound selected from the group consisting of phosphorus compounds represented by the following general formula (1) and salts thereof. (1)

In the general formula (1), the number 1 or more hydrocarbon group having a carbon, preferably a hydrocarbon group having 1 to 30 carbon atoms, R ₂及Pi 1 ₃ are each independently hydrogen or a C 1 -C Represents up to 30 hydrocarbon groups. These hydrocarbon groups may contain nitrogen or Z or oxygen.

Examples of the hydrocarbon group include an alkyl group, a cycloalkyl group, an alkyl group, an alkyl-substituted cycloalkyl group, an aryl group, an alkyl-substituted aryl group, and an arylalkyl group. Methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, butyl group, octyl group, noninole group, decyl group, pendecyl group, dodecyl group, tridecyl group, tetradecyl group, ぺNantadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, icosyl, henycosyl, docosyl, tricosyl, tetracosyl, pentacosyl, hexacosyl, heptacosyl, octacosinole, nonacosyl, Alkyl groups such as triacontyl group (these are linear May be branched or branched), cyclopentyl group, cyclohexynole group, cycloheptyl group, etc., cycloalkyl group having 5 to 7 carbon atoms, methylcyclopentyl group, dimethylcyclopentyl group, methylethyl Cyclopentyl group, acetylcyclopentyl group, methylcyclohexyl group, dimethylcyclohexyl group, methylethylcyclohexyl group, ethynolecyclohexyl / methyl group, methynolecycloheptinol group, dimethylinolecycloheptinol group, methylethylcycloheptyl group An alkylcycloalkyl group having 6 to 10 carbon atoms (the substitution position of the alkyl group with the cycloalkyl group is also arbitrary), a pthenyl group, a pentenyl group, a hexenyl group, a heptyl group, an octenyl group, a nonenyl group, Decenyl, decenyl, dodecenyl, tri Alkenyl groups such as decenyl group, tetradecenyl group, pentadecenyl group, hexadecenyl group, heptadecenyl group, octadecenyl group and nonadecenyl group (these alkenyl groups may be linear or branched, and the position of the double bond is also arbitrary. ), Phenyl, naphthyl, and other aryl groups, tolyl, xylyl, ethylphenyl, propylphenyl, butylphenyl, and other C7-C10 alkylaryl groups. May be substituted or substituted at any position.), A benzyl group, a phenylethyl group, a phenylpropyl group, a phenylbutyl group and other aryl groups having 7 to 10 carbon atoms. Alkyl groups (these alkyl groups may be linear or branched).

The hydrocarbon group is an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 24 carbon atoms. And more preferably an alkyl group having 1 to 18 carbon atoms.

Examples of the phosphorus compound represented by the general formula (1) include: a hydrocarbon group having 1 or more carbon atoms, a phosphonic acid having both R ₂ and R ₃ being hydrogen; and a hydrocarbon having 1 or more carbon atoms. a group, R ₂ in及Pi 1 ₃ on one hydrocarbon group having 1 to 3 0 carbon atoms, phosphonate monoester other person is hydrogen, but Ri 1 or more hydrocarbon groups der carbon atoms, R Examples include phosphonic acid diesters in which ₂ and R ₃ are both hydrocarbon groups having 1 to 30 carbon atoms, and mixtures thereof.

Specific examples of these phosphorus compounds include mono-n-butylphosphonic acid, mono-isobutinolephosphonic acid, mono-n-pentynolephosphonic acid, mono-n-hexynolephosphonic acid, and mono-1,3-dimethylbutylphosphonic acid , Mono 4-methyl-1-pentyl phosphonic acid, Mono n-heptyl phosphonic acid, Mono n-octyl phosphonic acid, Mono 2-ethylhexyl phosphonic acid, Monoisodecyl / lephosphonic acid, Mono n-dodecyl phosphonic acid, Monodiisotridecyl phosphonic acid Alkyl or alkynolephosphonic acid such as acid, monooleylphosphonic acid, monostearylphosphonic acid, monon-octadecylphosphonic acid, etc .; n-butynolephosphonic acid mono-n-butynole ester, isoptinole phosphonate monoisobutylene / reestenole, n —Pentylphosphonic acid mono n-pliers Monoester, n-hexynolephosphonic acid mono-n-hexynolephosphonate, 1,3-dimethynolebutynolephosphonic acid mono-1,3-dimethynolebutynoleestenolate, 4-methinole 2-pentynylphosphonic acid mono-4-methynolenate 2-pentynoleestenole, n-heptinolephosphonic acid mono η-heptyl ester, η-octylphosphonic acid mono η-octyl ester, 2-ethylhexylphosphonic mono-2-ethylhexyl ester, isodecylphosphonic monoiso Decyl ester, η-dodecyl phosphonic acid mono η-dodecyl ester, isotridecyl phosphonic acid monoisotridecyl ester, oleyl phosphonic acid monooleinole ester, stearinole phosphonate monostearyl ester, octadecyl phosphonic acid monoester Octadecyl ester Monooctyl tyl phosphonate, monooleyl butyl phosphonate, monobutyl enosyl ester of 2-ethylhexylphosphonate, monooleyl ester of 2-ethyl hexynolephosphonate, monomethyl oleyl phosphonate, monobutyl oleyl phosphonate Estenolle, Oleinolephosphonic acid Monooctinole Estenole, Oleinolephosphon Mono- and di-n-butyl / phosphine mono-esters of alkyl or alkenyl phosphonates such as mono-dodecyl ester of acid, octadecinole phosphonate monomethyl ester and octa decyl phosphonate monoethyl ester; Diisobutyl ester phosphonate, n-pentyl phosphonate di-n-pentyl ester, n-hexyl phosphonate di-n-hexyl ester, 1,3-dimethylbutyl phosphonate di 1,3-dimethynolebutyl ester, 4-Methylenol 2-pentylphosphonic acid di 4-pentynyl-2-pentyl ester, n-Heptinolephosphonic di-n-Heptinole ester, n-octynolephosphonic di-n-octynoleestenolle, 2-ethylhexyl Diphosphonic acid di-2-ethylhexyl ester, isodecylphosphone Jiisodeshi glycol ester, _n - dodecyl phosphonic acid di n- dodecyl ester, iso-tridecyl phosphonate Jiiso tridecyl esters, Oreiruhosuhon acid di O rail esters, stearyl acid distearyl ester, O Kuta decyl phosphonic acid Jiokuta decyl ester Honoré, O Alkyl or alkenyl phosphonic acid diesters such as octadecylphosphonic acid dimethyl ester, octadecylphosphonic acid dimethyl ester, oleylphosphonic acid dimethyl ester, stearylphosphonic acid dimethyl ester, etc .; And mixtures thereof.

Further, as the salt of the phosphorus compound represented by the general formula (1), a phosphorus compound wherein R i is a hydrocarbon group having 1 or more carbon atoms and at least one of R ₂ and R ₃ is hydrogen Metal bases such as metal oxides, metal hydroxides, metal carbonates, and metal chlorides, ammonia, amines having only a hydrocarbon group having 1 to 30 carbon atoms or a hydroxyl group-containing hydrocarbon group in the molecule Salts obtained by reacting a nitrogen compound such as a compound to neutralize a part or all of the remaining acidic hydrogen can be given.

Examples of the metal in the metal base include alkali metals such as lithium, sodium, potassium and cesium, alkaline earth metals such as calcium, magnesium, and palladium, zinc, copper, iron, lead, and nickel. And heavy metals such as silver, manganese and molybdenum. Of these, alkaline earth metals such as calcium and magnesium and zinc are preferred, and zinc is particularly preferred.

The structure of the metal salt of the phosphorus compound varies depending on the valence of the metal and the number of OH groups of the phosphorus compound. Therefore, the structure is not limited at all. When lead lmo 1 and phosphonic acid monoester (one OH group) 2 mo 1 are reacted, it is thought that a compound having the structure represented by the following formula is obtained as the main component, but there are also polymerized molecules. it seems to do.

Also, for example, when zinc oxide lmo 1 is reacted with phosphonic acid lmo 1 (two OH groups), it is thought that a compound having a structure represented by the following formula is obtained as a main component. It is thought that molecules also exist.

Specific examples of the nitrogen compound include ammonia, monoamine, diamine, and polyamine. More specifically, methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, noelamine, decylamine, pendecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecylamine, hexadecylamine, pentadecylamine, hexadecamine Decylamine, octadecylamine, dimethylamine, getylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, didecylamine, didodecylamine, ditridecylamine Ditetradecylamine, dipentadecylamine, dihexadecylamine, diheptadecylamine, dioc C1-C30 alkyl groups such as tadecylamine, methylethylamine, methylpropylamine, methylbutylamine, ethylpropylamine, ethylbutylamine, and propylbutylamine Is an alkylamine having a straight or branched chain; an alkenyl group having 2 to 30 carbon atoms such as etyramine, propenylamine, butenylamine, octenylamine, and oleylamine (these alkenyl groups may be linear or branched). May be branched) Alkenylamines: methanolamine, ethanolamine, propanolamine, butanolamine, pentanolamine, hexanolamine, heptanolamine, octanol / reamine, nonanolamine, methanolethanolanolamine, methanolpropanolamine, methanolbutanol C1-C30 alkanol groups such as amide, ethanolpropanolamine, ethanolbutanolamine and propanolbutanolamine (these alkanol groups may be linear or branched) An alkanolamine having an alkylene group having 1 to 30 carbon atoms, such as methylenediamine, ethylenediamine, propylenediamine, and butylenediamine; diethylenetriamine; Polyamines such as tylenetetramine, tetraethylenepentamine, and pentaethylenehexamine; pentadecyl getylamine, pentadecyl cetanolamine, dodecyldipropanolenoamine, oleyl cetanolamine, oleyl A compound having an alkyl or alkenyl group having 8 to 20 carbon atoms in the above monoamine, diamine, or polyamine such as propylene diamine or stearyl tetraethylene pentamine; or a heterocyclic compound such as N-hydroxyxethylolylimidazoline; Examples thereof include alkylene oxide adducts of compounds; and mixtures thereof.

Among these nitrogen compounds, aliphatic amines having an alkyl or alkenyl group having 10 to 20 carbon atoms such as decylamine, dodecylamine, tridecylamine, heptadecylamine, octadecylamine, oleylamine, and stearylamine (these are directly It may be chain or branched.) Is a preferred example. One or more of these components (A) can be arbitrarily compounded.

In the present invention, as the component (A), when used in combination with the component (B), the wear resistance can be synergistically improved, and further lower phosphorus and lower ash can be _achieved. Is preferably a hydrocarbon group having 1 or more carbon atoms, and R ₂ and R ₃ are each a phosphonic acid diester comprising a hydrocarbon group having 1 to 30 carbon atoms, and among them, is a group having 10 to 30 carbon atoms. It is particularly preferable that the hydrocarbon group has 12 to 18 carbon atoms, and that R ₂ and R ₃ are each a hydrocarbon group having 1 to 9 carbon atoms, preferably 1 to 4 carbon atoms, and more preferably a methyl group. .

The content of the component (A) in the lubricating oil composition for an internal combustion engine of the present invention is particularly limited. However, the lower limit is usually based on the total amount of the composition, in terms of phosphorus element,

It is 0.001% by mass, preferably 0.01% by mass, more preferably 0.02% by mass, and the upper limit is not particularly limited. Although it may also be provided, it is usually 0.2% by mass, preferably 0.1% by mass, more preferably 0.08% by mass, particularly preferably 0% by mass in terms of phosphorus element, based on the total amount of the composition. .05% by mass. By setting the content of the component (A) to the above lower limit or more, excellent extreme pressure properties and excellent anti-wear properties can be obtained. In addition, when the amount is less than the above upper limit, the phosphorus content of the lubricating oil can be reduced. In particular, when the amount is 0.08% by mass or less, further 0.05% by mass or less, the influence on an exhaust gas purification device or the like is extremely reduced. It is possible to obtain a low-phosphorus-type lubricating oil composition for an internal combustion engine with a small amount. The component (B) in the present invention is zinc dithiophosphate having a secondary alkyl group. For example, zinc di-secondary alkyl dithiophosphate, mono-secondary alkyl zinc dithiophosphate or mono-secondary alkyl dithiophosphate represented by the following general formula (2): Partially polymerized secondary zinc monoalkyldithiophosphate and the like can be exemplified.

^R4CR4C

In the formula, R ₄ , R ₅ , R ₆ and R ₇ each independently represent a secondary alkyl group having 3 to 24 carbon atoms.

Here, the secondary alkyl group refers to a group represented by the following general formula (3).

In the above formula (3), ₁₈ and ₁₉ each independently have 1 to 22 carbon atoms, preferably 1 to 8 carbon atoms, and the total carbon number of R ₈ and R ₉ is 2 to 23 A linear or branched alkyl group, preferably 2-9. Specifically, R ₈ and R ₁₉ are each independently a linear or branched methyl group, ethyl group, propyl group, butyl group, benzyl group, hexyl group, heptyl group, and octyl group. Group, nonyl group, decyl group, resin Examples thereof include a sil group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, and a hexadecyl group. ·

The method for producing the zinc secondary alkyldithiophosphate is not particularly limited, and any conventional method can be employed. For example, an alcohol or phenol having a secondary monoalkyl group corresponding to R ₄ , R ₅ , R ₆ and R ₇ is reacted with diphosphorus pentasulfide to produce dithiophosphoric acid, which is neutralized with zinc oxide or the like. It can be synthesized by letting it go. Thereby, zinc dithiophosphate having a secondary alkyl group can be obtained.

Particularly preferred as the zinc secondary (sec) alkyldithiophosphate are zinc mono- or di-sec-butyldithiophosphate, zinc mono- or di-sec-pentyldithiophosphate, mono- or di-4-methyl-2-pentyldithiophosphate. Zinc phosphate, zinc mono- or di-sec-hexyldithiophosphate, zinc mono- or di-sec-octyldithiophosphate, zinc mono- or di-sec-decyldithiophosphate, mono- or di-sec-zinc tridecyldithiophosphate And mixtures thereof.

The content of the component (B) in the lubricating oil composition for an internal combustion engine of the present invention is not particularly limited, but its lower limit is usually 0.001 based on the total amount of the composition and in terms of phosphorus element. The mass is ⁰ », preferably 0.01 mass%, more preferably 0.02 mass%, and the upper limit is not particularly limited, and a high concentration lubricating oil additive composition may be used. a force based on the total amount of the composition which can provide, in terms of phosphorus amount is usually 0.1 mass ^_0/0, preferably from 0.08% by mass, more preferably 0.05 mass%, particularly preferably 0.035 % By mass. By setting the content of the component (B) to be equal to or more than the above lower limit, excellent extreme pressure properties and antiwear properties can be obtained. In addition, when the amount is less than the above upper limit, it is possible to realize a low phosphorous content of the lubricating oil. It is possible to obtain an extremely low lubricating oil composition for a low phosphorus type internal combustion engine.

The content ratio of the component (A) to the component (B) in the present invention is not particularly limited, but is preferably 10:90 to 90:10 in terms of the mass ratio in terms of the amount of phosphorus element. The ratio is more preferably 20:80 to 80:20, even more preferably 30:70 to 70:30, and particularly preferably 35:65 to 65:35. New When the content ratio of the component (A) and the component (B) is within the above range, the wear resistance can be synergistically improved.

In addition, the total content of the component (A) and the component (B) in the present invention is not particularly limited, but the lower limit is usually 0.001 in terms of phosphorus element based on the total amount of the composition. the mass ^_0/0, preferably 0.0 1% by weight, more preferably from 0.02% by mass, and the upper limit is not particularly limited, a high concentration of the lubricating oil additive composition Although it may be provided, it is usually 0.2% by mass, preferably 0.1% by mass, more preferably 0.08% by mass, and further preferably, in terms of phosphorus element, based on the total amount of the composition. 0.06 mass%, particularly preferably 0.05 mass%. By setting the content of the component (A) to the component (B) at or above the lower limit, excellent extreme pressure properties and wear resistance can be obtained. Further, when the amount is not more than the above upper limit, the phosphorus content of the lubricating oil can be reduced. In particular, since a synergistic effect of the component (A) and the component (B) can be expected, further reduction of the phosphorus can be realized. In particular, by setting the total content of the components (A) and (B) to 0.08% by mass or less, and even 0.05% by mass or less, a low-phosphorous type that has extremely little effect on exhaust gas purification devices and the like. The lubricating oil composition for an internal combustion engine can be obtained. The lubricating oil composition of the present invention preferably contains (C) a chain terminator. Chain terminators are generally distinguished from peroxide decomposers such as sulfur-containing organometallic compounds or organosulfur compounds (eg, zinc dithiophosphate, molybdenum dithiophosphate, olefin sulfide, sulfide, etc.). The function of stopping the chain of oxidative deterioration, such as capturing and stabilizing the radicals generated during the oxidative deterioration process of the lubricating oil, either becoming stable radicals themselves or further capturing and stabilizing the radicals. It has. Examples of the chain terminator include a phenol-based antioxidant, an amine-based antioxidant, and the like, but are not limited to compounds having the same action mechanism.

Examples of phenolic antioxidants include 4,4,1-methylenebis (2,6-di-tert-butylphenol) and 4,4′-bis (2,6-ditert-butyl-butenophenol) , 4,4'-bis (2-methynole-6-tert-butynolepheno), 2,2'-methylenebis (4-ethyl-6-tert-ptinolephenone), 2,2'-methylenebis (4— Methynoreh 6-tert-butyl phenol), 4, 4,1-butylidenebis (3-methyl-6-tert-butylphenol), 4,4'-isopropylidenebis (2,6-di-tert-butylphenol), 2,2, -methylenebis (4-methyl-6-noyl) Phenol), 2,2,1-isobutylidenebis (4,6-dimethylphenol), 2,2, -methylenebis (4-methynole 6-hexylhexylphenol), 2,6-di-tert-butynole 4 -Methinoref enonole, 2,6-di-tert-butinole 4-ethinolephenol, 2,4-dimethyi / le 6-tert-Ptinolephenol, 2,6-di-tert-a-dimethinoleamino-p- Cresol, 2,6-di-ert-butynole 4 (N, N, 1-dimethylaminomethylphenol), 4,4, -thiobis (2-methyl-6-tert-butylphenol), 4,4,1-thiobis (3 — Chinole 6-tert-butyl / rephenol, 2,2,1-thiobis (4-methyl-6-tert-butylphenol), bis (3-methinolate 4-hydroxy-5-tert-butylbenzyl) sulfide , Bis (3,5-di-tert-butyl-4-hydroxybenzyl) sulfide, 2,2'-thiodiethylenebis [3_ (3,5-zy tert-butyl-4-hydroxyphenyl) propionate ], Tridecyl- ₃ — (3,5-di-tert-butyl-4-hydroxyphene / re) propionate, pentaerythricyl-tetrakis [3_ (3,5-di-tert-butyl-1-4-hydroxyphenyl) propionate] Octyl-3- (3,5-di-tert-butyl-1 4-hydroxyphenyle) propionate, octadecyl-1-31 (3,5-di-tert-butyl-4-hydroxyf) Can be exemplified a two-Honoré) propionate, Okuchiru _ 3 _ (3-methyl-5-tert-butyl one 4-arsenide Dorokishifueniru) Puropione bets such as preferred examples. These may be used as a mixture of two or more.

Examples of the amine-based antioxidants include phenyl-naphthylamine, alkylphenyla-naphthylamine, dialkyldiphenylamine, and phenothiazine. These may be used as a mixture of two or more. As the chain terminator in the present invention, among the above, an antioxidant composed of a phenolic antioxidant and a Z or amine antioxidant is particularly preferable.

In the lubricating oil composition of the present invention, the content of the component (c) is usually preferably _5.0 % by mass / ₀ or less, more preferably 3.0% by mass, based on the total amount of the lubricating oil composition. /. Less than And more preferably 2.5% by mass or less. If the content is more than 5.0% by mass, it is not preferable because sufficient base number maintenance property corresponding to the compounding amount cannot be obtained. On the other hand, its content is preferably at least 0.1% by mass, more preferably at least 1% by mass, based on the total amount of the lubricating oil composition in order to further enhance the base number retention. The lubricating oil composition of the present invention preferably contains (D) an ashless dispersant and Z or (E) a metal-based detergent.

(D) As the ashless dispersant, any ashless dispersant used in lubricating oils can be used.For example, a linear or branched alkyl or alkenyl group having 40 to 400 carbon atoms can be used. A nitrogen-containing compound having at least one in the molecule or a derivative thereof, or a modified product of arkeel succinic acid imide. One or two or more selected from these can be blended.

The carbon number of this alkyl group or alkenyl group is 40 to 400, preferably 60 to 350. When the number of carbon atoms in the alkyl group or alkenyl group is less than 40, the solubility of the compound in the lubricating base oil decreases, while when the number of carbon atoms in the alkyl group or alkenyl group exceeds 400, the lubricating oil composition It is not preferable because the low-temperature fluidity of the material deteriorates. The alkyl group or alkenyl group may be linear or branched, but is preferably a group selected from oligomers of olefins such as propylene, 1-butene and isobutylene, and co-oligomers of ethylene and propylene. Derived branched alkyl groups and branched alkenyl groups are exemplified.

Specific examples of the component (D) include, for example, the following compounds. One or more compounds selected from these can be used.

(D-1) succinic imid having at least one alkyl or alkenyl group having 40 to 400 carbon atoms in the molecule, or a derivative thereof

(D-2) Benzylamine having at least one alkyl or alkenyl group having 40 to 400 carbon atoms in the molecule, or a derivative thereof

(D-3) a polyamine having at least one alkyl or alkenyl group having 40 to 400 carbon atoms in the molecule, or a derivative thereof

More specifically, the above (D-1) succinic acid imide is represented by the following general formula (4) And compounds can be exemplified represented by the general formula (5) ₍

In the general formula (4), R ² ° represents an alkyl group or an 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. Is shown.

In the general formula (5), R ^{2 1}及Pi R ^{2 2} are each independently C 4 0-4 0 0, preferably an 6 0-3 5 0 alkyl or alkenyl group, is Poributeyuru group Is preferred. i represents an integer of 0 to 4, preferably 1 to 3.

In addition, succinic acid imid is a so-called mono-type succinic acid imid represented by the formula (4) in which succinic anhydride is added to one end of a polyamine, and a compound in which succinic anhydride is added to both ends of a polyamine. (5) Power containing so-called bis-type succinic acid imid represented by (5) The composition of the present invention may contain any of them or a mixture thereof.

The method for producing these succinic acid imides is not particularly limited.For example, a compound having an alkyl group or an alkyl group having 40 to 400 carbon atoms is mixed with maleic anhydride at 100 to 200 ° C. By reacting an alkyl or alkenyl succinic acid obtained by the reaction with a polyamine. Specific examples of the polyamine include dimethylene triamine, triethylene tetramine, tetraethylene pentamine, and pentaethylene hexamine.

More specifically, the above (D_2) benzylamine is represented by the following general formula (6) And the like.

In the general formula (6), R ²³ represents an alkyl group or an alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350 carbon atoms, and j represents an integer of 1 to 5, preferably 2 to 4.

The method for producing this benzylamine is not particularly limited. For example, a polyolefin such as a propylene oligomer, a polybutene, and an ethylene-olefin copolymer is reacted with a phenol to form an alkylphenol, which is then added to formaldehyde. And a polyamine such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine by reacting by Mannich reaction.

More specifically, examples of the polyamine (D-3) include compounds represented by the following general formula (7).

R ²⁴ -NH- (CH ₂ CH ₂ NH) _k -H (7)

In the general formula (7), R ²⁴ represents an alkyl group or an alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350 carbon atoms, and k represents an integer of 1 to 5, preferably 2 to 4.

The method for producing this polyamine is not limited at all. For example, after chlorinating polyolefin such as propylene oligomer, polybutene, and ethylene monoolefin copolymer, ammonia, ethylenediamine, diethylenetol, etc. It can be obtained by reacting a polyamine such as liamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine. As the derivatives of the nitrogen-containing compound mentioned as an example of the component (D), specifically, for example, the above-mentioned nitrogen-containing compound may be a monocarboxylic acid having 1 to 30 carbon atoms (such as a fatty acid). Polycarboxylic acids having 2 to 30 carbon atoms such as acids, trimellitic acid and pyromellitic acid or anhydrides or ester compounds thereof; alkylene oxides having 2 to 6 carbon atoms; hydroxy (poly) oxyalkylene carbonate Etc. A compound modified with a so-called oxygen-containing organic compound by neutralizing or amidifying a part or all of the remaining amino group and amino group or imino group by acting on the above-mentioned nitrogen-containing compound; A so-called boron-modified compound in which a part or all of the remaining amino group and Z or imino group is neutralized or amidated; a so-called boron-modified compound; Or a so-called phosphoric acid-modified compound in which some or all of the imino groups are neutralized or amidated; a sulfur-modified compound obtained by reacting a sulfur compound with the above-mentioned nitrogen-containing compound; and an oxygen-containing compound containing the above-described nitrogen-containing compound A modified compound obtained by combining two or more types of modification selected from an organic compound modification, boron modification, phosphoric acid modification, and sulfur modification. Among these derivatives, the boric acid-modified compound of alkenyl succinic acid imid has excellent heat resistance and antioxidant properties, and is effective in the lubricating oil composition of the present invention to further enhance the base number retention.

When the component (D) is contained in the lubricating oil composition of the present invention, its content is usually 0.01 to 20% by mass, preferably 0.1 to 1% by mass, based on the total amount of the lubricating oil composition. 0% by mass. When the content of the component (D) is less than 0.01% by mass, the effect on high-temperature cleanability is small. On the other hand, when the content exceeds 20% by mass, the low-temperature fluidity of the lubricating oil composition is significantly reduced. It is not preferable because it worsens.

(E) As the metal-based detergent, known metal-based detergents used for lubricating oils can be used. For example, alkali metal sulfonate or alkaline earth metal sulfonate, alkali metal phenate or alkaline earth metal Examples thereof include phenate, alkali metal salicylate, alkaline earth metal salicylate, and mixtures thereof.

More specifically, T as an alkali metal or earth metal sulfonate is used to sulfonate an alkyl aromatic compound having a molecular weight of 100 to 150, preferably 200 to 700. An alkali metal salt or an alkaline earth metal salt of an alkyl aromatic sulfonic acid obtained by the above method, particularly a magnesium salt and / or a calcium salt, is preferably used. Specific examples of the alkyl aromatic sulfonic acid include so-called petroleum Examples include sulfonic acid and synthetic sulfonic acid.

Petroleum sulfonic acid is generally a sulfonated alkyl aromatic compound in the lubricating oil fraction of mineral oil. So-called mahoganic acid, which is a by-product of white oil production. Are used. Examples of the synthetic sulfonic acid include an alkylbenzene having a linear or branched alkyl group, which is obtained as a by-product from an alkylbenzene production plant used as a raw material of a detergent or obtained by alkylating polyolefin to benzene. Is used as a raw material, and a sulfonated product thereof or a sulfonated product of dinonylnaphthalene is used. The sulfonating agent used for sulfonating these alkyl aromatic compounds is not particularly limited, but fuming sulfuric acid or sulfuric acid is usually used.

As the alkali metal or alkaline earth metal phenate, more specifically, an alkyl phthalate having at least one linear or branched alkyl group having 4 to 30 carbon atoms, preferably 6 to 18 carbon atoms. Phenol, an alkylphenol sulfide obtained by reacting this alkylphenol with elemental sulfur, or an alkali metal salt or an alkali metal salt of a Mannich reaction product of an alkylphenol obtained by reacting this alkylphenol with formaldehyde. Earth metal salts, particularly magnesium salts and potassium salts, are preferably used.

More specifically, the alkali metal or alkaline earth metal salicylate includes at least one straight-chain or branched alkyl group having 1 to 30 carbon atoms, preferably 10 to 26 carbon atoms. Alkali or alkaline earth metal salts of alkylsalicylic acid (e.g., phenol or talesol, etc., which are obtained by alkoxylation of olefins having 10 to 26 carbon atoms), for example, magnesium salts and / or Alternatively, calcium salts and the like, particularly calcium salts, are preferably used.

Alkali metal or alkaline earth metal sulfonate, alkali metal or alkaline earth metal phenate, and alkali metal or alkaline earth metal salicylate include anolequinole aromatic sulfonic acid, alkyl phenol, alkyl phenol sulfide, alkyl Mannich reaction product of phenol, alkyl salicylic acid, etc. is directly reacted with metal bases such as oxides or hydroxides of alkali metals or alkaline earth metals, or once alkalis such as sodium salts and potassium salts. Not only neutral salts (normal salts) obtained by substituting an alkaline earth metal salt with a metal salt, but also these neutral salts (normal salts) and excess alkali metal or alkaline earth metal salts Al-li metal or Al-earth metal base (Al-li metal or Al-earth metal The hydroxide or oxide) or basic salts obtained by heating in the presence of water, An overbased compound obtained by reacting a neutral salt (normal salt) with a base such as an alkali metal or alkaline earth metal hydroxide in the presence of carbon dioxide and boric acid or borate. Salts (ultrabasic salts) are also included.

These reactions are usually performed in a solvent (aliphatic hydrocarbon solvent such as hexane, aromatic hydrocarbon solvent such as xylene, light lubricating base oil, etc.). Metal-based detergents are usually commercially available diluted with a light lubricating base oil or the like, and are available. Generally, the metal content is 1.0 to 20 mass%. %, preferably 2.0 to 1 to use of 6 mass ^_0/0 it is desirable.

In the present invention, the total base number of the component (E) is preferably from 0 to 50 OmgKOH / g, more preferably from 20 to 45 OmgKOHZg. As the component (E), alkali metal or alkaline earth metal sulfonate, phenate, salicylate, etc. can be used alone or in combination of two or more kinds. Is preferably used as an essential component. Here, the total base number means the total base number measured by the perchloric acid method according to JIS K2501, “Petroleum products and lubricating oil-neutralization value test method”, paragraph 7.

Further, the component (E) of the present invention is not particularly limited in its metal ratio, and it is usually 20 or less, preferably 1-15. In the present invention, it is preferable to mix a metal-based detergent having a metal ratio of 3 or less as essential from the viewpoint of base number maintenance, and a metal-based detergent having a metal ratio of more than 3 and preferably a metal ratio of more than 5 It is preferable to use a metal-based detergent in that the antiwear property can be enhanced. Therefore, by appropriately selecting the type and metal ratio of these metal-based detergents and using them alone or in combination, it is possible to obtain desired base number maintenance properties and antiwear properties. Here, the metal ratio is represented by the valence of the metal element in the metal-based detergent X the content of the metal element (mo 1%) / the content of the soap group (mo 1%). , Calcium, magnesium and the like, and the soap group means a sulfonic acid group, a salicylic acid group and the like.

In the present invention, the compounding amount of the component (E) is not particularly limited, but usually, the upper limit is preferably 1% by mass in terms of a metal element, more preferably 0.5, based on the total amount of the composition. % By mass, more preferably 0.2% by mass, and can be appropriately selected according to the requirement of the sulfated ash content of the composition. The lower limit is usually 0.01% by mass, Preferably it is 0.02% by mass, particularly preferably 0.05% by mass. By setting the amount of the component (B) to be 0.01% by mass or more, it is possible to further improve the mouth drain performance such as high-temperature detergency, oxidation stability, and base number retention. In order to further improve the performance of the lubricating oil composition of the present invention, any additive generally used in lubricating oils can be added according to the purpose. Such additives include, for example, anti-wear agents other than component (A) and component (B), friction modifiers, viscosity index improvers, corrosion inhibitors, antioxidants, demulsifiers, metal deactivators And additives such as an antifoaming agent and a coloring agent.

Examples of the antiwear agent other than the component (A) and the component (B) include zinc dithiophosphate other than the component (B) (eg, zinc dithiophosphate having a primary alkyl group or aryl group), and zinc dithiophosphate other than the component (B). Metal salts of thiophosphoric acid esters, (sub) phosphoric acid esters, thio (sub) phosphoric acid esters, amine salts or metal salts thereof, phosphorus-containing carboxylic acid compounds such as j8-dithiophosphorylated propionic acid and the like Metal salts or esters thereof with fatty acids, disulfides, sulfurized olefins, sulfurized oils and fats, sulfur-containing compounds such as zinc dithiolbamate, and the like, usually in the range of 0.05 to 5% by mass. However, in the lubricating oil composition of the present invention, among these, a sulfur-containing compound, that is, these anti-wear agents are used. The content of the sulfur-containing compound used should be limited, for example, 0.1% by mass or less, preferably 0.05% by mass or less in terms of sulfur element. It is particularly preferred not to do so.

Examples of the friction modifier include molybdenum dithiol molybdate, molybdenum dithiophosphate, a molybdenum monoamine complex, a molybdenum-imido succinic acid complex, molybdenum disulfide, and an alkyl or alkenyl group having 6 to 30 carbon atoms. Fatty acids, fatty alcohols, fatty acid esters, fatty ethers, fatty acid amides, fatty amines, and the like, and mixtures thereof. These additives are useful in that they can add low friction performance to the composition.

As the viscosity index improver, specifically, a so-called non-dispersion type viscosity index improver such as a polymer or copolymer of one or more monomers selected from various methacrylates or a hydrogenated product thereof is used. , Or various methacrylic containing nitrogen compounds A so-called dispersion type viscosity index improver obtained by copolymerizing an acid ester, a non-dispersion type or dispersion type ethylene-a-olefin copolymer (Examples of a-olefin include propylene, 1-butene and 1-pentene.) Or hydrides thereof, polyisobutylene or hydrogenated products thereof, hydrides of styrene-one-gen copolymer, styrene-mono-maleic anhydride copolymer, polyalkylstyrene and the like.

The molecular weight of these viscosity index improvers must be selected in consideration of shear stability. Specifically, the number average molecular weight of the viscosity index improver is usually 5, 000 to: 1, 0000, 0000, preferably 1 in the case of, for example, a dispersion type and a non-dispersion type polymethacrylate. When the thing of 0,000 to 900,000 is polyisobutylene or a hydride thereof, it is usually 800 to 5,000, preferably 1,000 to 4,0,0. In the case where the ethylene is an ethylene-a-olefin copolymer or a hydride thereof, it is usually 800 to 500,000, preferably 3,000 to 200,000. Is used.

Examples of the corrosion inhibitor include benzotriazole-based, tolyltriazole-based, thiadiazole-based, and imidazole-based compounds.

Examples of the antioxidant include petroleum sulfonate, alkylbenzene sulfonate, dinonylnaphthalene sulfonate, alkenyl succinate, and polyhydric alcohol ester.

Examples of the demulsifier include polyalkylene glycol-based nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene annalequinolephenyl ether, and polyoxyethylene alkynolenaphthyl ether. .

Examples of the metal deactivator include, for example, imidazoline, pyrimidine derivative, alkylthiaziazole, mercaptobenzothiazole, benzotriazole or a derivative thereof, 1,3,4-thiadiazole polysulfide, 1,3,4-thiadiazolyl12 , 5-bisdialkyldithiocarbamate, 2_ (alkyldithio) benzoimidazole, and] 3- (o-potoxybenzylthio) propionnitrile.

Examples of the antifoaming agent include silicone, fluorosilicole, and fluoroalkyl ether. When these additives are contained in the lubricating oil composition of the present invention, the content is 0.1 to 20% by mass in the viscosity index improver based on the total amount of the lubricating oil composition, a friction modifier, 0.005 to 5% by mass for corrosion inhibitors, antioxidants, and demulsifiers, 0.05 to 1% by mass for metal deactivators, and 0.0005 to 1 for defoamers. Usually selected in the range of mass%.

The lubricating oil composition of the present invention can synergistically improve extreme pressure and abrasion resistance by using the component (A) and the component (B) together as described above, It is capable of exhibiting value maintenance performance. Therefore, a low phosphorus lubricating oil composition with a phosphorus content of 0.08% by mass or less, or further reduced to 0.05% by mass or less, as specified in the next ILSACGF-4 gasoline engine oil standard. It is also very useful as a low-phosphorus, low-sulfur lubricating oil composition in which the sulfur content is reduced to 0.3% by mass or less, preferably 0.2% by mass or less, particularly preferably 0.1% by mass or less. It is.

Since the lubricating oil composition of the present invention is excellent in the effect of preventing abrasion, it is preferably used as a lubricating oil for internal combustion engines such as gasoline engines, motorcycle engines, diesel engines, and gas engines for motorcycles, automobiles, power generation and ships. For low-sulfur, low-phosphorus lubricating oils, especially exhaust gas purifying catalysts selected from oxidation catalysts, three-way catalysts, NOX storage reduction catalysts and / or exhaust gas aftertreatment devices such as DPF, especially oxidation catalysts and DPF or NOX storage It is suitable for an internal combustion engine equipped with an exhaust gas aftertreatment device combining a reduction catalyst and DPF. In addition, low-sulfur fuels such as gasoline with a sulfur content of 50 mass ppm or less, more preferably 30 mass ppm or less, particularly preferably 10 mass ppm or less, or gas oil or kerosene, or a sulfur content of 1 mass ppm or less Especially lubricating oils for internal combustion engines using fuels (LPG, natural gas, hydrogen-free dimethyl ether, alcohol, GTL (gas to liquid) fuel, etc.), especially for gasoline engines or gas engines It can be preferably used.

Further, lubricating oils of the present invention that require the above-mentioned extreme pressure performance or wear prevention performance, for example, lubricating oils for driving systems such as automatic or manual transmissions, gear oils, darries, wet brake oils It can also be suitably used as a lubricating oil such as a hydraulic oil, a turbine oil, a compressor oil, a bearing oil, and a refrigerating machine oil.

The low-sulfur, low-phosphorus engine system of the present invention comprises a lubricating oil composition for an internal combustion engine. A lubricating oil composition containing the above components (A) and (B) in a lubricating base oil, having a sulfur content of 0.3% by mass or less and a phosphorus content of 0.08% by mass or less. The fuel used is a fuel with a sulfur content of 50 mass ppm or less.While having low sulfur and low phosphorus, the anti-wear property is improved, and oxidation catalyst, three-way catalyst, NO x absorption reduction The effect on exhaust gas purifying catalysts selected from catalysts and / or exhaust gas aftertreatment devices such as DPF can be reduced.

[Industrial applicability]

As described above, the lubricating oil composition for an internal combustion engine of the present invention is a lubricating oil composition having excellent extreme pressure properties and antiwear properties. Therefore, the present invention can be applied to the various lubricating oils described above where these performances are required. In addition, high-temperature detergency, oxidation stability, and the like can be further improved by optimizing the type and content of the metal-based detergent and ashless dispersant. Further, as a low-sulfur, low-phosphorus lubricating oil composition having a sulfur content of 0.3% by mass or less and a phosphorus content of 0.08% by mass or less, Can be set to a desired level (for example, 0.01 to 1.2% by mass, preferably 0.8% by mass or less, more preferably 0.6% by mass or less). Purification equipment (for example, exhaust gas catalysts such as three-way catalysts, oxidation catalysts, NOx storage reduction catalysts, etc., and lubricating oils for internal combustion engines, because they do not deteriorate the purification performance of Z or DPF (diesel particulate filter)) Further, the present invention provides a low-sulfur, low-phosphorus lubricating oil composition for lubricating an internal combustion engine and using a low-sulfur fuel to improve the performance of an exhaust gas purifying apparatus. Maintain low sulfur, low phosphorus engine It is useful as a stem (for example, low-sulfur gas oil with a sulfur content of 50 mass ppm or less; power-generating engine systems using sulfur-free gasoline, LP gas or natural gas, etc. as fuel, engine systems for automobiles, etc.). is there.

[Best Mode for Carrying Out the Invention]

Hereinafter, the content of 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. (Example 1 and Comparative Examples:! ~ 3)

A lubricating oil composition of the present invention having the composition shown in Table 1 (Example 1) and a lubricating oil composition for comparison (Comparative Examples 1 to 3) were prepared. The obtained composition was subjected to the following performance evaluation tests (1) and (2), and the obtained results are shown in Table 1.

(1) High-speed four-ball test

In a high-speed four-ball test in accordance with ASTM D 2 78 3-88, the load (LNS L) at the time of abrasion was measured at room temperature, at a rotation speed of 1800 rpm, and under gradually applied load. The higher the LNS L value (N), the better the wear resistance and extreme pressure.

(2) Falex test

In a Falex test conforming to ASTM D3233, as an A method, a load (lbs) when seizure occurred at a rotation speed of 290 rpm and an oil temperature of 52 ° C was measured. Also, as method B, the load (lbs) at the time of seizure was measured under the conditions that the load was gradually increased after running-in operation at 290 rpm, oil temperature of 80 ° C, and 250 bs x 5 minutes for 5 minutes. It was measured. The higher the seizure load, the better the extreme pressure property. As is clear from Table 1, the components (A) and (B) were used together in a mass ratio of 40:60 in terms of phosphorus element, the sulfur content of the composition was 0.07% by mass, The content is 0.05 mass. The composition (Example 1) with / ₀ was compared with the composition (Comparative Examples 1 and 3) in which the component (B) or the component (A) was not used and the phosphorus content was 0.05% by mass. Excellent anti-wear and extreme pressure properties. Especially in the Falex test, it can be seen that the seizure load is synergistically improved. In addition, it can be seen that a remarkable seizure load is exhibited as compared with the case of using zinc dithiophosphate having a primary monoalkyl group instead of the component (A) in the composition of Example 1 (Comparative Example 2). It has been confirmed that the base number retention of the composition of Example 1 is superior to that of a conventional composition containing about 0.1% by mass of zinc dithiophosphate in terms of phosphorus element.

In addition, in the valve wear test (100 hours, sulfur-free gasoline with a sulfur content of 10 mass ppm or less was used as fuel) in the valve operating wear test according to JAS OM 328-95 for the composition of Example 1, It has been confirmed that it has excellent system wear prevention performance. table 1

1) Hydrorefined mineral oil, kinematic viscosity @ 100 ° C: 4.7mm ² / s, viscosity index: 120, sulfur content: 10 mass ppm% CA: 0.6

2) The following octadecylphosphonic acid dimethyl ester, phosphorus content: 8.6% by mass

3) zinc dialkyldithiophosphate, alkyl group: sec-butyl group or 4-methyl 2-pentyl group, phosphorus content: 7.2% by mass

4) Zinc dialkyldithiophosphate, 2-ethylhexyl group, phosphorus content: 7.2% by mass

5) 4,4'-methylenebis-1,2,6-ditert-butylphenol and dialkyldiphenylamine

6) Polyvinyl succinimide, nitrogen content: 2.0% by mass, weight average molecular weight: 3000

7) Ga salicylate, total base number: 170 mgKOH / g, metal ratio: 2.7, calcium content: 6% by mass

8) Additives including viscosity index improver (PMA OCP), defoamer, etc.

2) 0

I レ 0— CH ₃

-P \

Ό 一 CH ₃

Claims

The scope of the claims

1. a lubricating base oil comprising (A) at least one selected from the group consisting of phosphorus compounds represented by the general formula (1) and salts thereof; and (B) zinc dithiophosphate having a secondary alkyl group. A lubricating oil composition for an internal combustion engine, comprising:

(In the general formula (1), a hydrocarbon group (which may contain nitrogen and / or oxygen), R ₂ and R ₃ are each independently hydrogen or a hydrocarbon group having 1 to 30 carbon atoms (nitrogen and / or oxygen). Z or oxygen may be contained).

2. The lubricating oil composition for an internal combustion engine according to claim 1, comprising (C) a chain terminator.

3. The lubricating oil composition for an internal combustion engine according to claim 1, comprising (D) an ashless dispersant and / or (E) a metal-based detergent.

4. The lubricating oil composition for an internal combustion engine according to claim 3, wherein the (D) ashless dispersant is modified with boric acid.

5. The lubricating oil for an internal combustion engine according to claim 1, wherein the total content of the component (A) and the component (B) is 0.08% by mass or less in terms of a phosphorus element. Composition.

6. The content of the i-containing compound (excluding component (B)) used as an antiwear agent is 0.1% by mass or less in terms of the i-element based on the total amount of the composition. 2. A lubricating oil composition for an internal combustion engine according to item 1 above.

7. The lubricating oil composition for an internal combustion engine according to claim 1, wherein the lubricating base oil has a percentage of 3 or less and a sulfur content of 0.05% by mass or less.

8. The lubricating oil for an internal combustion engine according to any one of claims 1 to 7, wherein the internal combustion engine uses a fuel having a sulfur content of 50 mass ppm or less. Composition.

9. The internal combustion engine is an internal combustion engine equipped with an exhaust gas purifying catalyst selected from an oxidation catalyst, a three-way catalyst, a NOx storage reduction catalyst, and Z or DPF. Item 14. The lubricating oil composition for an internal combustion engine according to any one of the above items.

10. The lubricating base oil contains at least one component selected from the above-mentioned component (A) and (B) zinc zinc dithiophosphate, and has a sulfur content of 0.3 mass based on the total amount of the composition. % Lubricating the internal combustion engine with a lubricating oil composition for an internal combustion engine having a phosphorus content of 0.08 mass% or less, and using a fuel having a sulfur content of 50 mass ppm or less. Sulfur, low phosphorus engine system.