JP2006124536A - Lubricating oil composition suitable for lead-containing metallic material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lubricating oil composition capable of preventing lead corrosion which occurs even in such a situation that a base number enough remains in the composition although it is used for a long period, while the lubricating oil composition is decreased in an amount of zinc dithiophosphate, or does not contain the same, and tends to extremely cause the corrosion of a lead-containing metal, such as a lead-containing sliding material. <P>SOLUTION: This lubricating oil composition contains the zinc dithiophosphate in a base oil for a lubrication oil in an amount of ≤0.08 mass% as an amount of phosphorus, or does not contain the same, and is suitable for being in contact with a lead-containing metallic material, wherein the lubricating oil composition contains, as component (A), a dialkylsalicylate expressed by general formula (1) (R<SP>1</SP>and R<SP>2</SP>are identical to or different from each other and are each a 1-40C hydrocarbon group which may contain oxygen or nitrogen; M is an alkali metal or an alkaline earth metal; and n is 1 or 2 corresponding to a valence of the metal) and/or a (hyper)basic salt thereof as components. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lubricating oil composition suitable for contact with a lead-containing metal material, and more specifically, corrosion or corrosive wear of a lead-containing sliding material can be suppressed even when the content of zinc dithiophosphate is small. The present invention relates to a lubricating oil composition.

  As the sliding material for engines and the like, iron-based and aluminum-based metal materials are mainly used. However, among sliding materials, lead-containing metal materials may be used for sliding parts such as main bearings and connecting rod bearings, for example, metal materials such as aluminum, copper, and tin. These lead-containing metal materials have an excellent feature that there is little fatigue phenomenon, but on the other hand, there is a drawback that corrosion wear is large.

Causes of corrosion wear include accumulation of peroxide accumulated due to deterioration of oil (for example, Non-Patent Document 1) and direct oxidation with molecular oxygen in air (for example, Non-Patent Documents 2 to 4). Can be mentioned. It is also known that oxidation products such as quinone, diacetyl, nitric oxide, and nitro compounds promote corrosion by coexisting with an acid (for example, Non-Patent Document 5). Actual corrosion is complex because it is governed by many factors, but to prevent corrosion, in general,
・ Antioxidation of lubricating oil ・ Destruction of oxidizing substances ・ Suppression of formation of corrosive oxidation products ・ Deactivation of oxidizing substances ・ Formation of anti-corrosion coating on metal surfaces are important. More specifically,
・ Peroxide decomposing agents such as zinc dithiophosphate and sulfides and anticorrosive film forming agents ・ Amine-based and phenol-based anti-chain antioxidants ・ Anti-corrosive film forming agents such as benzotriazole ・ Cleaning and dispersing agents The effect of preventing corrosion due to the addition of an acid neutralizer is known, and most of these components are generally used in combination.

  In particular, sulfur-containing wear inhibitors such as zinc dithiophosphate are extremely effective for preventing corrosion and wear of lead-containing sliding materials. For example, in a conventional engine oil in which zinc dithiophosphate is mixed in an amount of about 0.1% (about 0.2% by mass of sulfur) in terms of phosphorus, the surface of lead is deactivated together with the peroxide decomposition effect. An excellent lead corrosion wear prevention effect is exhibited, but it is known that when the content of zinc dithiophosphate is reduced, the lead corrosion wear prevention effect deteriorates exponentially (for example, non-patent literature) 6). On the other hand, sulfur-containing compounds such as zinc dithiophosphate are susceptible to sulfide corrosion on non-ferrous base metal-containing sliding materials other than lead (eg, copper, tin, silver, etc.), and corrosion inhibitors such as benzotriazole are copper. It has been found that although it is effective in preventing corrosion of lead, it does not show sufficient effect in preventing lead corrosion.

  By the way, against the backdrop of recent demands for reducing environmental impact, there is a growing demand for low phosphorus or low sulfur as well as long life of engine oil. The long life of engine oil is the fuel in gasoline engines and diesel engine engines. Suppression of engine oil deterioration caused by fuel, such as reduction of sulfur content in gas, and widespread use of gas-fueled engine engines, higher performance of engine oil itself (increased antioxidant, wear inhibitor, metal detergent and other additives, etc.) ) To achieve a long life in terms of base number maintenance (see, for example, Patent Document 1). Further, it has been found that a longer life can be achieved by using a salicylate detergent having a lower metal ratio (for example, Patent Documents 2 to 4).

Also, in diesel engine engines, the amount of sulfated ash in the engine oil is reduced in order to suppress deposits on exhaust purification devices such as DPF, and in gas engine engines, to suppress deposits in the combustion chamber that cause abnormal combustion. The demand for reduction is high, and when reducing metal-based detergents, it is considered that the use of salicylate-type detergents is most preferable from the viewpoint of maintaining the base number.
Ind.Eng.Chem., 36 (1944), 477 Ind.Eng.Chem., 37 (1945), 90 Ind.Eng.Chem., 49 (1957), 1703 J. Inst. Petrol., 37 (1951), 225 Ind.Eng.Chem., 37 (1945), 917 Edited by Toshio Sakurai, Petroleum Product Additives, Second Edition, page 271 Figure-8 (issued June 15, 1979, Kobo Shobo) JP 2002-294271 A JP 2003-277781 A Japanese Patent Laid-Open No. 2003-277782 JP 2003-277783 A

  The inventors of the present invention have reduced the zinc dithiophosphate or reduced and / or reduced sulfur-free engine oils, particularly salicylate detergents that are excellent in oxidation stability and most effective in maintaining base number. In the case of using, the anti-wear performance for various sliding materials (iron-based, aluminum-based, copper-based, lead-based, etc.) when used for a longer period than before was examined. Then, it was found that the corrosion wear of the lead-containing sliding material may occur remarkably despite the fact that the total base number of the lubricating oil remains sufficiently and has not reached the end of its life. In particular, lead corrosion is significant in an oxidizing gas atmosphere, so that the degradation of peroxide and the formation of anticorrosion coating on lead can be reduced by reducing, not using, or disappearing zinc dithiophosphate after long-term use. Along with disappearance, it is thought that the degradation products of the lubricating oil act on the lead surface and accelerate lead corrosion. This lead corrosion phenomenon occurs despite the fact that the salicylate-based detergent remains sufficiently and has acid neutralizing ability and antioxidant performance, so that the zinc dithiophosphate that has been conventionally used is reduced or reduced. It can be said that this is a new problem that has become apparent when it is not contained. In addition, as a salicylate type | system | group detergent, as disclosed by patent documents 1-4 mentioned above, the monoalkyl type salicylate type detergent is common.

  That is, the problem of the present invention is that a base number during long-term use remains in a lubricating oil composition in which zinc dithiophosphate is reduced or not contained, and corrosion of lead-containing metals such as lead-containing sliding materials is significant. It is an object of the present invention to provide a lubricating oil composition suitable for contact with a lead-containing metal material capable of suppressing lead corrosion that occurs even in the situation.

  As a result of intensive studies to solve the above problems, the present inventors have determined that corrosion or corrosive wear of lead-containing metal materials is achieved by optimizing metal-based detergents even when zinc dithiophosphate is reduced or not contained. The present invention has been completed.

  That is, the present invention is a lubricating oil composition in which zinc dithiophosphate is contained in a lubricating base oil in a phosphorus amount of 0.08% by mass or less, or does not contain, and is in contact with a lead-containing metal material, the component (A) And a dialkyl salicylate represented by the general formula (1) and / or a (over) basic salt thereof.

In the general formula (1), R ¹ and R ² may be the same or different and each represents a hydrocarbon group having 1 to 40 carbon atoms, and the hydrocarbon group may contain oxygen or nitrogen. M represents an alkali metal or an alkaline earth metal, and n represents 1 or 2 depending on the valence of the metal.

  Further, the present invention does not contain 0.08% by mass or less of zinc dithiophosphate as a phosphorus amount in the lubricating base oil based on the total amount of the composition, and (A) a dialkyl represented by the general formula (1) Lubricating oil containing 0.005 to 5% by mass of salicylate and / or its (over) basic salt as a metal amount and 0.001 to 0.1% by mass of (B) an organomolybdenum compound as a molybdenum amount It is a composition.

  The lubricating oil composition of the present invention suppresses lead (Pb) corrosion or corrosive wear, particularly when zinc dithiophosphate, which is extremely effective in preventing lead (Pb) corrosion or corrosive wear, is reduced or not contained. It is a lubricating oil composition suitable for contact with a lead-containing metal material, and can be reduced in sulfur, further reduced in phosphorus, reduced in ash, and has an excellent long drain property. . Accordingly, not only as a lubricating oil for internal combustion engines in contact with a lead-containing metal material, particularly as diesel engine oil or gas engine oil with a lead-based sliding material, but also a device having a lubrication system in which the lead-containing metal material and the lubricant come into contact Lubricating oils, for example, automatic transmissions, manual transmissions, continuously variable transmissions, gear system lubricating oils, greases, wet brake oils, hydraulic fluids, turbine oils, compressor oils, bearing oils, refrigeration machine oils, etc. It can also be suitably used as a lubricating oil.

  In the lubricating oil composition of the present invention, the zinc dithiophosphate content is 0.08% by mass or less as the phosphorus amount or does not contain this, and corrosion or corrosive wear of the lead-containing metal material that becomes noticeable in that case It is a lubricating oil composition suitable for preventing.

  In the lubricating oil composition of the present invention, the zinc dithiophosphate content is 0.08% by mass or less as the phosphorus content or does not contain this, and includes a conventional general monoalkyl type salicylate detergent. It is a lubricating oil composition useful as an alternative for preventing corrosion or corrosive wear of lead-containing metal materials that becomes particularly prominent. Hereinafter, the lubricating oil composition (also simply referred to as a lubricating oil composition) that comes into contact with the lead-containing metal material of the present invention will be described in detail.

  In the present invention, the lead-containing metal material is not limited as long as lead is present on the metal surface in contact with the lubricating oil of the present invention. Not only lead, but also lead alloys, lead or lead alloys can be selected from various metals. Examples thereof include a metal material coated on the surface of the substrate. Moreover, even if the lead-containing metal material is coated with a non-lead-containing metal material on its surface, the coated surface is worn away in the process of use, and the lead-containing metal material is exposed, and is in contact with the lubricating oil of the present invention. This includes cases where there is a possibility of doing so.

  Examples of lead alloys include lead-tin alloys, lead-copper alloys, lead-tin-copper alloys, lead-aluminum alloys, lead-aluminum-silicon alloys, lead-aluminum-tin alloys, lead-aluminum-copper alloys, Lead-aluminum-silicon-tin alloy, lead-aluminum-silicon-copper alloy, lead-aluminum-tin-copper alloy, lead-aluminum-silicon-tin-copper alloy, and the like. As these lead-containing metal materials, It is preferable that the metal material contains a lead content of preferably 1% by mass or more, more preferably 2% by mass or more, further preferably 5% by mass or more, and further preferably 10% by mass or more. Specifically, a lead-tin-containing alloy containing 50 to 95 mass%, preferably 60 to 90 mass% of lead, and a lead-copper-containing alloy containing 5 to 50 mass%, preferably 10 to 30 mass% of lead. And a lead-aluminum-containing alloy containing 1 to 10% by mass, preferably 2 to 5% by mass of lead.

  The lubricating oil composition of the present invention is useful because the higher the lead content on the metal surface, the more likely lead corrosion or corrosion wear occurs.

  The lubricating base oil in the present invention is not particularly limited, and mineral oil base oils and synthetic base oils used for ordinary lubricating oils can be used. Specifically, as the mineral base oil, the lubricating oil fraction obtained by subjecting the crude oil to atmospheric distillation obtained under reduced pressure is subjected to solvent removal, solvent extraction, hydrocracking, Examples include those refined by performing one or more treatments such as solvent dewaxing, hydrorefining, etc., or base oils produced by a method of isomerizing wax isomerized mineral oil, GTL WAX (Gas Liquid Wax).

  The sulfur content in the mineral oil base oil is not particularly limited, but is usually 0 to 1.5% by mass, preferably 0.2% by mass or less, more preferably 0.05% by mass or less, Preferably it is 0.005% by mass or less, and by reducing the sulfur content of the lubricating base oil, it is more excellent in long drainage, and when used as a lubricating oil for internal combustion engines, it has an adverse effect on the exhaust gas aftertreatment device Can be obtained as much as possible.

  The saturated content of the mineral oil base oil is not particularly limited, but is usually 50 to 100% by mass, preferably 60% by mass or more, and more preferably 90% by mass in terms of excellent oxidation stability and long drainability. % Or more, more preferably 95 mass% or more.

  In addition, the said saturated part means the saturated part measured based on ASTM D2549.

  Specific examples of synthetic base oils include polybutene or hydrides thereof; poly-α-olefins such as 1-octene oligomers and 1-decene oligomers or hydrides thereof; ditridecyl glutarate, di-2-ethylhexyl adipate Diesters such as diisodecyl adipate, ditridecyl adipate, and di-2-ethylhexyl sebacate; neopentyl glycol ester, trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol-2-ethylhexanoate, and pentaerythritol Examples thereof include polyol esters such as pelargonate; aromatic synthetic oils such as alkyl naphthalene, alkyl benzene, and aromatic esters, or mixtures thereof.

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

The kinematic viscosity of the lubricating base oil used in the present invention is not particularly limited, but the kinematic viscosity at 100 ° C. is preferably 20 mm ² / s or less, more preferably 16 mm ² / s or less. On the other hand, the kinematic viscosity is preferably 3 mm ² / s or more, more preferably 5 mm ² / s or more. When the kinematic viscosity at 100 ° C. of the lubricating base oil exceeds 20 mm ² / s, the low-temperature viscosity characteristic deteriorates. On the other hand, when the kinematic viscosity is less than 3 mm ² / s, an oil film is formed at the lubrication point. Insufficient lubrication results in poor lubricity and increases the evaporation loss of the lubricating base oil, which is not preferable.

  The amount of evaporation loss of the lubricating base oil is preferably 20% by mass or less, more preferably 16% by mass or less, and further preferably 10% by mass or less in terms of NOACK evaporation. % Or less is more preferable, and 5% by mass or less is particularly preferable. When the NOACK evaporation amount of the lubricating base oil exceeds 20% by mass, not only the evaporation loss of the lubricating oil is large and the long drain property is inferior, but also when used as a lubricating oil for an internal combustion engine, Phosphorus compounds or metal components may accumulate in the exhaust gas purification device together with the lubricating base oil, which is not preferable because there is a concern about adverse effects on the exhaust gas purification performance. Here, the NOACK evaporation amount is measured in accordance with ASTM D5800.

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

  Examples of the zinc dithiophosphate in the present invention include those represented by the following general formula (2).

In the formula, R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent a hydrocarbon group having 1 to 24 carbon atoms, and these hydrocarbon groups having 1 to 24 carbon atoms include those having 1 to 24 carbon atoms. A linear or branched alkyl group, a linear or branched alkenyl group having 3 to 24 carbon atoms, a cycloalkyl group having 5 to 13 carbon atoms, or a linear or branched alkylcycloalkyl group, It is preferably any of an aryl group having 6 to 18 carbon atoms, a linear or branched alkylaryl group, an arylalkyl group having 7 to 19 carbon atoms, and the like. The alkyl group or alkenyl group may be primary, secondary or tertiary.

Among the hydrocarbon groups that R ³ , R ⁴ , R ⁵ and R ⁶ can take, the hydrocarbon group is a linear or branched alkyl group having 1 to 18 carbon atoms or 6 carbon atoms. Particularly preferred is an aryl group of ˜18 or a linear or branched alkylaryl group.

Any conventional method can be adopted as a method for producing zinc dithiophosphate, and is not particularly limited. Specifically, for example, it has a hydrocarbon group corresponding to R ³ , R ⁴ , R ⁵ and R ^6. It can be synthesized by reacting alcohol or phenol with diphosphorus pentasulfide to produce dithiophosphoric acid and neutralizing it with zinc oxide. The structure of zinc dithiophosphate varies depending on the starting alcohol used.

  The upper limit of the content of zinc dithiophosphate in the lubricating oil composition of the present invention is 0.08% by mass or less, preferably 0.05% by mass or less, more preferably 0.04% by mass or less as the phosphorus content. The lower limit is not particularly limited, and it is desirable not to contain this from the viewpoint of maintaining the base number, and it is possible to contain lead by using the (A) component described later or the (A) component and the (B) component in combination. Although the corrosion of the metal material can be suppressed, in order to improve the corrosion or corrosion wear prevention performance of the lead-containing metal material as necessary, the content is preferably 0.01% by mass or more, more preferably as phosphorus amount. Preferably it is good also as 0.02 mass% or more.

  When the content of zinc dithiophosphate exceeds 0.08% by mass as the amount of phosphorus, for example, when the amount of phosphorus is 0.10% by mass or more, the conventional lubricating oil deviates from the conditions in which the problem of the present invention becomes significant. Yes, although the lead-containing metal material is excellent in corrosion or corrosion wear prevention performance, it is not preferable from the viewpoint of low sulfur, low phosphorus, or long life.

  The lubricating oil composition of the present invention contains a dialkyl salicylate represented by the general formula (1) and / or a (over) basic salt thereof as the component (A).

R ¹ and R ² in the general formula (1) may be the same or different and each represents a hydrocarbon group having 1 to 40 carbon atoms, which may contain oxygen and nitrogen. M represents an alkali metal or an alkaline earth metal, preferably sodium, potassium, calcium, magnesium, etc., preferably calcium, magnesium, particularly calcium, and n represents 1 or 2 depending on the valence of the metal.

  Examples of the hydrocarbon group having 1 to 40 carbon atoms include alkyl groups, cycloalkyl groups, alkenyl groups, alkyl-substituted cycloalkyl groups, aryl groups, alkyl-substituted aryl groups, and arylalkyl groups. Are methyl, ethyl, propyl, butyl, pentyl, hexyl, peptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, 1 to 40 carbon atoms such as heptadecyl group, octadecyl group, nonadecyl group, icosyl group, heicosyl group, docosyl group, tricosyl group, tetracosyl group, pentacosyl group, hexacosyl group, heptacosyl group, octacosyl group, nonacosyl group, and triacontyl group Alkyl groups (these are linear Or may be branched), a cycloalkyl group having 5 to 7 carbon atoms such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a methylcyclopentyl group, a dimethylcyclopentyl group, a methylethylcyclopentyl group, a diethylcyclopentyl group, An alkylcycloalkyl group having 6 to 10 carbon atoms such as methylcyclohexyl group, dimethylcyclohexyl group, methylethylcyclohexyl group, diethylcyclohexyl group, methylcycloheptyl group, dimethylcycloheptyl group, methylethylcycloheptyl group (cycloalkyl of alkyl group); The substitution position on the group is also arbitrary), butenyl group, pentenyl group, hexenyl group, heptenyl group, octenyl group, nonenyl group, decenyl group, undecenyl group, dodecenyl group, tridecenyl group, tetradecenyl group, An alkenyl group such as an interdecenyl group, hexadecenyl group, heptadecenyl group, octadecenyl group, nonadecenyl group (these alkenyl groups may be linear or branched, and the position of the double bond is arbitrary), phenyl group, naphthyl group Aryl groups such as aryl group such as aryl group, tolyl group, xylyl group, ethylphenyl group, propylphenyl group, butylphenyl group, etc. (the alkyl group may be linear or branched, aryl group Substitution position is also arbitrary), arylalkyl groups having 7 to 10 carbon atoms such as benzyl group, phenylethyl group, phenylpropyl group, phenylbutyl group (these alkyl groups may be linear or branched) Can be mentioned.

Moreover, there is no restriction | limiting in particular as a combination of said R < ¹ >, R < ² >, However, As a preferable thing, the combination of (a)-(d) shown below is mentioned.
(A) R ¹ and R ² are the same, each having 10 to less than 20 carbon atoms, preferably 14 to 18 hydrocarbon groups (b) R ¹ and R ² are the same, each having 20 to 40 carbon atoms, Preferably 20-30 hydrocarbon groups (c) R ¹ and R ² are different, each one hydrocarbon group selected from 10-40 carbon atoms, preferably each hydrocarbon having less than 10-20 carbon atoms One of the group and a hydrocarbon group having 20 to 40 carbon atoms (d) R ¹ and R ² , preferably a hydrocarbon group having 14 to 18 carbon atoms, and the other one being less than 10 carbon atoms, Preferably less than 5, particularly preferably one hydrocarbon group (e) ^one of R ¹ and R ² is a hydrocarbon group having 20 to 40 carbon atoms, preferably 20 to 30 carbon atoms, and the other is less than 10 carbon atoms. , Preferably less than 5, particularly preferably 1 Hydrocarbon group

Among them, any of them may be used, but the above (a) or (d) is particularly preferable, and (d) is most preferable, and R ¹ is particularly a hydrocarbon group having 10 to 20 carbon atoms, R ² Is preferably a hydrocarbon group having less than 10 carbon atoms.

  In addition, as a C10-C40 hydrocarbon group, the secondary alkyl group represented by following General formula (3) induced | guided | derived from polymers or copolymers, such as ethylene, propylene, butylene, is preferable.

  Here, x and y are 0 to 37, and x + y is 7 to 37, preferably x, y is 0 to 27, and x + y is 7 to 27, more preferably x, y is 0 to 16, and x + y is 7 to 27. 16, or x and y are 0 to 23, and x + y is 17 to 23, particularly preferably x, y is 0 to 15, and x + y is an integer of 11 to 15.

  Examples of the hydrocarbon group having less than 10 carbon atoms include alkyl groups having 1 to less than 10 carbon atoms such as a methyl group, an ethyl group, a butyl group, and a t-butyl group, which contain oxygen or nitrogen. For example, a -COOH group may be mentioned. Among these, a t-butyl group and a methyl group are preferable, and a methyl group is most preferable.

As a method for producing the component (A) is not particularly limited, JP-B 48-35325 and JP-may be a known method disclosed in JP-B-50-3082 Publication, ^{e.g., R} 1, When one of R ² is an alkyl group having 10 to less than 20 carbon atoms or 20 to 30 carbon atoms and the other is a methyl group, the ortho-cresol or para-cresol is used as a starting material, and the carbon number is 10 at the para or ortho position. Alkylation using olefins having less than -20 or 20 to 30 carbons, followed by carboxylation, and further reacting with a metal base such as an oxide or hydroxide of an alkali metal or alkaline earth metal, or once a sodium salt Or an alkali metal salt such as a potassium salt and then substituted with an alkaline earth metal salt. In the case of a dialkyl type salicylate in which both R ¹ and R ² are an alkyl group having less than 10 to 20 carbon atoms or 20 to 30 carbon atoms, phenol is used as a starting material and the number of carbons is twice that amount (mol). Alkylation using less than 10-20 and / or olefins having 20-30 carbons, followed by carboxylation and further reacting with a metal base such as an oxide or hydroxide of an alkali metal or alkaline earth metal, or Once obtained as an alkali metal salt such as sodium salt or potassium salt, it is obtained by replacing with an alkaline earth metal salt.

  The (A) of the present invention includes not only the neutral salts obtained as described above, but also these neutral salts and excess alkali metal or alkaline earth metal salts, alkali metals or alkaline earth metals. Basic salts obtained by heating a base (alkali metal or alkaline earth metal hydroxide or oxide) in the presence of water, or neutral salts in the presence of carbon dioxide, boric acid or borates Also included are overbased salts obtained by reacting with a base such as an alkali metal or alkaline earth metal hydroxide.

  Although the metal ratio of (A) component of this invention does not have a restriction | limiting in particular, The thing of 1-40 can be used normally, Preferably it is 1.1-10, More preferably, it is 1.2-8. In particular, when the component (A) having a metal ratio of 2 or less is used, not only is the base number maintainability particularly excellent, but also the corrosion or corrosion wear of the lead-containing metal material compared to the case of using a monoalkyl salicylate having the same metal ratio. This is useful because it can be significantly reduced. Further, by using the component (A) having a metal ratio of 2 or more, preferably 2.6 or more, more preferably 4.5 or more, it becomes easier to suppress corrosion or corrosive wear of the lead-containing metal material. The metal ratio here is represented by the valence of the metal element in the metal detergent × the content of the metal element (mol%) / the content of the soap group (mol%). The soap group is a salicylic acid group. Show.

  The content of the dialkyl salicylate represented by the general formula (1) which is the component (A) of the present invention is 0.005 to 5% by mass, preferably 0.01 as the amount of metal (alkali metal or alkaline earth metal). From the viewpoint of reducing the influence on the exhaust gas aftertreatment device, when the sulfated ash content of the composition is 1% by mass or less, preferably 0.3% by mass or less, more preferably It is 0.24 mass% or less.

  In addition to the dialkyl salicylate as the component (A), the lubricating oil composition of the present invention includes a salicylate-based detergent other than the component (A), a sulfonate detergent, a finate detergent, and a carboxylate detergent. Metal-based detergents such as can be added.

  Examples of the salicylate detergent other than the component (A) include monoalkyl salicylates represented by the general formula (4) and / or (over) basic salts thereof.

In the general formula (4), R ⁷ is an alkyl group having 10 to less than 40 carbon atoms, preferably less than 10 to 20 carbon atoms or 20 to 30 carbon atoms, preferably a secondary alkyl group, and M is Alkali metal or alkaline earth metal is shown, sodium, potassium, calcium, magnesium, etc., preferably calcium, magnesium, especially calcium is desirable, and n is 1 or 2 depending on the valence of the metal.

  Examples of the alkyl group having 10 to 40 carbon atoms include secondary decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, and nonadecyl group. A polymer having a distribution of 10 to less than 40, preferably less than 10 to 20 or 20 to 30 and particularly preferably 14 to 18 carbon atoms derived from a polymer or copolymer such as ethylene, propylene and butylene. Secondary alkyl group.

  More specifically, the sulfonate detergent is a metal salt of an alkyl aromatic sulfonic acid obtained by sulfonated an alkyl aromatic compound having a molecular weight of 100 to 1500, preferably 200 to 700, preferably an alkaline earth. Metal salts, particularly magnesium salts and / or calcium salts are preferably used, and specific examples of alkyl aromatic sulfonic acids include so-called petroleum sulfonic acids and synthetic sulfonic acids.

  As the petroleum sulfonic acid, there are generally used those obtained by sulfonating an alkyl aromatic compound of a lubricating oil fraction of mineral oil, so-called mahoganic acid that is produced as a by-product when white oil is produced. As the synthetic sulfonic acid, for example, an alkylbenzene having a linear or branched alkyl group, which is obtained as a by-product from an alkylbenzene production plant that is a raw material for detergents or by alkylating polyolefin into benzene, is used as a raw material. And those obtained by sulfonating this, or those obtained by sulfonating dinonylnaphthalene. The sulfonating agent for sulfonating these alkyl aromatic compounds is not particularly limited, but usually fuming sulfuric acid or sulfuric acid is used.

  Examples of the alkaline earth metal sulfonate include those represented by the following general formula (5) or (6).

In the formula, R ⁸ and R ⁹ may be the same or different and each represents a linear or branched alkyl group having 4 to 30 carbon atoms, preferably 8 to 25, and M ¹ is an alkaline earth metal, preferably Represents calcium and / or magnesium.

  More specifically, the finate-based detergent is an alkylphenol having at least one linear or branched alkyl group having 4 to 30 carbon atoms, preferably 6 to 18 carbon atoms, and reacting this alkylphenol with elemental sulfur. A metal salt, preferably an alkaline earth metal salt, particularly a magnesium salt and / or a calcium salt of an alkylphenol sulfide product obtained by reacting the alkylphenol obtained by reacting the alkylphenol with formaldehyde is preferable.

  Examples of the alkaline earth metal finate include those represented by the following general formulas (7) to (9).

In the formula, R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , R ¹⁴ and R ¹⁵ may be the same or different, and each represents a linear or branched alkyl group having 4 to 30 carbon atoms, preferably 6 to 18 carbon atoms. M ² , M ³ and M ⁴ are each an alkaline earth metal, preferably calcium and / or magnesium, and x is an integer of 1 to 2.

  Further, metal detergents other than the component (A) can also be used for alkyl aromatic sulfonic acid, alkylphenol, alkylphenol sulfide, Mannich reaction product of alkylphenol, alkyl salicylic acid, etc., and alkaline earth metal of magnesium and / or calcium directly. Neutrality obtained by reacting with alkaline earth metal bases such as oxides and hydroxides, or by once replacing alkali metal salts such as sodium salts and potassium salts with alkaline earth metal salts Not only salts (normal salts), but also neutral salts (normal salts) and excess alkaline earth metal salts and alkaline earth metal bases (hydroxides and oxides of alkaline earth metals) in the presence of water Basic salt obtained by heating with, and neutral salt (normal salt) in the presence of carbon dioxide, boric acid or borate It includes alkali metal or overbased salts obtained by reaction with a base such as hydroxides of alkaline earth metals (overbased salts).

  These reactions are usually carried out in a solvent (an aliphatic hydrocarbon solvent such as hexane, an aromatic hydrocarbon solvent such as xylene, a light lubricating base oil). In addition, metal detergents are usually marketed in a state diluted with a light lubricating base oil or the like, and are available, but generally the metal content is 1.0 to 20% by mass. It is desirable to use 2.0 to 16% by mass.

  In the lubricating oil composition of the present invention, when a metallic detergent other than the component (A) is added, the amount of addition depends on the amount of the component (A), but in terms of the total amount of the composition, in terms of metal elements The amount is 0.005 to 5% by mass, preferably 0.01 to 0.5% by mass, and more preferably 0.01 to 0.3% by mass.

  In addition, it is desirable to use a metal ratio of the metal detergent other than the component (A) is usually 1 to 40, preferably 1 to 20, particularly preferably 5 to 15. In particular, when the component (A) and the sulfonate detergent are used in combination, the lead-containing metal material is not only excellent in suppressing corrosion or corrosive wear regardless of the metal ratio of the component (A) or the sulfonate detergent, but also stored. Although a composition excellent in stability can be obtained, the sulfonate-based detergent having a component (A) having a metal ratio of 2 or less, preferably 1.5 or less, and a metal ratio of 1 to 20, preferably 5 to 15 It is particularly preferable to use an agent in combination not only to increase the base number maintainability of the composition but also to suppress an increase in viscosity. In this case, the content of the component (A) having a metal ratio of 2 or less is preferably 0.01 to 0.1% by mass, more preferably 0.02 to 0.08% by mass, based on the total amount of the composition. %, And a metal detergent other than the component (A), particularly a sulfonate detergent having a metal ratio of 1 to 15, is preferably 0.1 to 0.3% by mass, more preferably 0.15 to 0, as a metal amount. Desirably, 2% by mass. The metal ratio here is represented by the valence of the metal element in the metal-based detergent × metal element content (mol%) / soap group content (mol%), and the soap group is a salicylic acid group, A sulfonic acid group, a phenol group, a carboxylic acid group, etc. are shown.

  In order to further improve the performance of the lubricating oil composition of the present invention or depending on other purposes, any additive generally used in lubricating oils can be added. Examples of such additives include organic molybdenum compounds, ashless dispersants, antioxidants, friction modifiers, antiwear agents other than zinc dithiophosphate, viscosity index improvers, corrosion inhibitors, rust inhibitors, and demulsifiers. And additives such as metal deactivators, antifoaming agents, and colorants.

  The lubricating oil composition of the present invention preferably contains an organomolybdenum compound as the component (B). Examples of the organic molybdenum compound include sulfurized molybdenum dithiocarbamate or sulfurized oxymolybdenum dithiocarbamate, sulfurized molybdenum dithiophosphate or sulfurized oxymolybdenum dithiophosphate, molybdenum amine complex, molybdenum succinimide complex, organic acid molybdenum salt, alcohol A molybdenum salt etc. can be illustrated. In the present invention, from the viewpoint of excellent corrosion resistance or corrosion wear prevention performance of lead-containing metal materials and from the viewpoint of reducing sulfur, an amine complex of molybdenum which is an organic molybdenum compound not containing sulfur, a succinimide complex of molybdenum, an organic acid Molybdenum salts of alcohols and molybdenum salts of alcohols are preferred, molybdenum amine complexes of molybdenum, molybdenum salts of phosphorus-containing acids, and molybdenum salts of alcohols are more preferred, and molybdenum amine complexes of molybdenum are particularly preferred.

The molybdenum - The molybdenum compounds constituting the amine complex, molybdenum trioxide or its hydrate _{(MoO 3 · nH 2 O)} , molybdic acid _(H 2 _MoO 4), molybdenum acid alkali metal salts _(M 2 _MoO 4; M represents an alkali metal salt), ammonium molybdate ((NH ₄ ) ₂ MoO ₄ or (NH ₄ ) ₆ [Mo ₇ O ₂₄ ] · 4H ₂ O), MoCl ₆ , MoOCl ₄ , MoO ₂ Cl ₂ , MoO Molybdenum compounds containing no sulfur, such as ₂ Br ₂ and Mo ₂ O ₃ Cl _6, can be mentioned. Among these molybdenum compounds, tetravalent to hexavalent, particularly hexavalent molybdenum compounds are preferable from the viewpoint of the yield of the target compound. Further, from the viewpoint of availability, among the hexavalent molybdenum compounds, molybdenum trioxide or a hydrate thereof, molybdic acid, an alkali metal salt of molybdic acid, and ammonium molybdate are preferable.

  The amine compound constituting the molybdenum-amine complex is not particularly limited, and examples thereof include ammonia, monoamine, diamine, polyamine, and alkanolamine. More specifically, methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecylamine , Hexadecylamine, heptadecylamine, octadecylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, diundecylamine, didodecylamine, ditridecylamine Decylamine, ditetradecylamine, dipentadecylamine, dihexadecylamine, diheptadecylamine, dioctadecylamine, methyl ethyl An alkylamine having 1 to 30 carbon atoms such as amine, methylpropylamine, methylbutylamine, ethylpropylamine, ethylbutylamine, and propylbutylamine (these alkyl groups may be linear or branched); , Alkenyl groups having 2 to 30 carbon atoms such as propenylamine, butenylamine, octenylamine, and oleylamine (these alkenyl groups may be linear or branched); carbons such as methylenediamine, ethylenediamine, propylenediamine, and butylenediamine Alkylene diamine having an alkylene group of 1 to 30; polyamine such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine; methanolamine, ethanol Min, propanolamine, butanolamine, pentanolamine, hexanolamine, heptanolamine, octanolamine, nonanolamine, methanol ethanolamine, methanolpropanolamine, methanolbutanolamine, ethanolpropanolamine, ethanolbutanolamine, and propanolamine, Alkanolamines having 1 to 30 carbon atoms such as undecyldiethanolamine, dodecyldipropanolamine, oleyldiethanolamine (these alkanol groups may be linear or branched); undecyldiethylamine, oleylpropylenediamine, stearyl C8-20 alkyl group on the above monoamine, diamine, polyamine such as tetraethylenepentamine Examples thereof include compounds having an alkenyl group and heterocyclic compounds such as N-hydroxyethyl oleylimidazoline; alkylene oxide adducts of these compounds; and mixtures thereof. Among these amines, primary amines, secondary amines, and alkanolamines are preferable.

  Carbon number of the hydrocarbon group which the amine compound which comprises a molybdenum-amine complex has becomes like this. Preferably it is 4 or more, More preferably, it is 4-30, Most preferably, it is 8-18. When the number of carbon atoms of the hydrocarbon group of the amine compound is less than 4, the solubility tends to deteriorate. Moreover, by setting the number of carbon atoms of the amine compound to 30 or less, the molybdenum content in the organic molybdenum compound can be relatively increased, and the effect of the present invention can be further enhanced with a small amount of blending.

  The molybdenum-succinimide complex is a complex of a sulfur-free molybdenum compound as exemplified in the description of the molybdenum-amine complex and a succinimide having an alkyl group or alkenyl group having 4 or more carbon atoms. Is mentioned. Examples of the succinimide include succinimide having an alkyl group or an alkenyl group having 4 to 30 carbon atoms, preferably 8 to 18 carbon atoms. If the alkyl group or alkenyl group in the succinimide has less than 4 carbon atoms, the solubility tends to deteriorate. A succinimide having an alkyl group or an alkenyl group having more than 30 and not more than 400 carbon atoms can also be used. By setting the alkyl group or alkenyl group to 30 or less carbon atoms, molybdenum-succinic acid can be used. The molybdenum content in the imide complex can be relatively increased, and the effects of the present invention can be further enhanced with a small amount of blending.

  Examples of the molybdenum salt of an organic acid include salts of molybdenum bases such as molybdenum oxide or molybdenum hydroxide, molybdenum carbonate or molybdenum chloride exemplified in the description of the molybdenum-amine complex with an organic acid. It is done. Examples of the organic acid include phosphorus-containing acids and carboxylic acids, and phosphorus-containing acids represented by the following general formula (10) or (11) are particularly preferable.

(In the formula (10), n represents 1 or 0, R ¹⁶ represents a hydrocarbon group having 1 to 30 carbon atoms, R ¹⁷ and R ¹⁸ may be the same or different, and each represents a hydrogen atom or a carbon number. 1 to 30 hydrocarbon groups, at least one of which is a hydrogen atom.)

(In formula (11), n represents 1 or 0, R ¹⁹ represents a hydrocarbon group having 1 to 30 carbon atoms, R ²⁰ and R ²¹ may be the same or different, and each represents a hydrogen atom or a carbon number. 1 to 30 hydrocarbon groups, at least one of which is a hydrogen atom.)

The general formula (10), in (11), the hydrocarbon group having 1 to 30 carbon atoms represented by R ¹⁶ to R ^21, alkyl group, cycloalkyl group, alkenyl group, alkyl-substituted cycloalkyl group, an aryl Groups, alkyl-substituted aryl groups, and arylalkyl groups.

  Specifically, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group Group, hexadecyl group, heptadecyl group, and octadecyl group, etc., an alkyl group having 1 to 30 carbon atoms (these alkyl groups may be linear or branched); ethenyl group, propenyl group, butenyl group, pentenyl group, C2-C30 alkenyl groups such as hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl, heptadecenyl, octadecenyl, etc. The group may be straight or branched and double The linking position is also arbitrary); a cycloalkyl group having 5 to 7 carbon atoms such as cyclopentyl group, cyclohexyl group, and cycloheptyl group; methylcyclopentyl group, dimethylcyclopentyl group, methylethylcyclopentyl group, diethylcyclopentyl group, methylcyclohexyl Group, dimethylcyclohexyl group, methylethylcyclohexyl group, diethylcyclohexyl group, methylcycloheptyl group, dimethylcycloheptyl group, methylethylcycloheptyl group, diethylcycloheptyl group and the like, The substitution position on the cycloalkyl group is also arbitrary); aryl groups having 6 to 18 carbon atoms such as phenyl group and naphthyl group; tolyl group, xylyl group, ethylphenyl group, propylphenyl group, butylphenyl group, 7 to 7 carbon atoms such as an nthylphenyl group, a hexylphenyl group, a heptylphenyl group, an octylphenyl group, a nonylphenyl group, a decylphenyl group, an undecylphenyl group, a dodecylphenyl group, a diethylphenyl group, a dibutylphenyl group, and a dioctylphenyl group 26 alkylaryl groups (the alkyl group may be linear or branched, and the substitution position on the aryl group is arbitrary); benzyl group, phenylethyl group, phenylpropyl group, phenylbutyl group, phenylpentyl group And an arylalkyl group having 7 to 12 carbon atoms such as a phenylhexyl group (the alkyl group may be linear or branched).

  The hydrocarbon group having 1 to 30 carbon atoms is preferably a hydrocarbon group having 2 to 24 carbon atoms, more preferably a hydrocarbon group having 3 to 20 carbon atoms, and more specifically. Is preferably an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 24 carbon atoms, more preferably an alkyl group having 3 to 18 carbon atoms, and more preferably an alkyl group having 4 to 12 carbon atoms.

  Examples of the phosphorus-containing acid represented by the general formula (10) include phosphorous acid monoester having one hydrocarbon group having 1 to 30 carbon atoms, (hydrocarbyl) phosphonous acid, and 1 to 30 carbon atoms. Phosphite diesters having two hydrocarbon groups, (hydrocarbyl) phosphonous acid monoesters, and mixtures thereof.

  Examples of the phosphorus-containing acid represented by the general formula (11) include a phosphoric acid monoester having one hydrocarbon group having 1 to 30 carbon atoms, (hydrocarbyl) phosphonic acid, and the carbonization having 1 to 30 carbon atoms. Examples thereof include phosphoric acid diesters having two hydrogen groups, (hydrocarbyl) phosphonic acid monoesters, and mixtures thereof.

  Moreover, as carboxylic acid which comprises the molybdenum salt of carboxylic acid, either a monobasic acid or a polybasic acid may be sufficient.

  As the monobasic acid, a fatty acid having 2 to 30 carbon atoms, preferably 4 to 24 carbon atoms, is used. The fatty acid may be linear or branched, and may be saturated or unsaturated. . Specifically, for example, acetic acid, propionic acid, linear or branched butanoic acid, linear or branched pentanoic acid, linear or branched hexanoic acid, linear or branched heptane Acid, linear or branched octanoic acid, linear or branched nonanoic acid, linear or branched decanoic acid, linear or branched undecanoic acid, linear or branched dodecane Acid, linear or branched tridecanoic acid, linear or branched tetradecanoic acid, linear or branched pentadecanoic acid, linear or branched hexadecanoic acid, linear or branched heptadecane Acid, linear or branched octadecanoic acid, linear or branched hydroxyoctadecanoic acid, linear or branched nonadecanoic acid, linear or branched icosanoic acid, linear or branched Henicosanoic acid, linear or branched Saturated fatty acids such as cosanoic acid, linear or branched tricosanoic acid, linear or branched tetracosanoic acid, acrylic acid, linear or branched butenoic acid, linear or branched pentenoic acid, Linear or branched hexenoic acid, linear or branched heptenoic acid, linear or branched octenoic acid, linear or branched nonenoic acid, linear or branched decenoic acid, Linear or branched undecenoic acid, linear or branched dodecenoic acid, linear or branched tridecenoic acid, linear or branched tetradecenoic acid, linear or branched pentadecenoic acid, Linear or branched hexadecenoic acid, linear or branched heptadecenoic acid, linear or branched octadecenoic acid, linear or branched hydroxyoctadecenoic acid, linear or branched nonadecene Acid, linear or branched Unsaturated fatty acids such as cocenoic acid, linear or branched heicosenoic acid, linear or branched docosenoic acid, linear or branched tricosenoic acid, linear or branched tetracosenoic acid, and the like And the like.

  Moreover, as a monobasic acid, in addition to the fatty acid, a monocyclic or polycyclic carboxylic acid (which may have a hydroxyl group) may be used, and the carbon number thereof is preferably 1 to 30, more preferably. Is 7-30. Monocyclic or polycyclic carboxylic acid is an aromatic carboxylic acid having 0 to 3, preferably 1 to 2 linear or branched alkyl groups having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms. Or cycloalkyl carboxylic acid etc. are mentioned, More specifically, (alkyl) benzene carboxylic acid, (alkyl) naphthalene carboxylic acid, (alkyl) cycloalkyl carboxylic acid etc. can be illustrated. Preferable examples of the monocyclic or polycyclic carboxylic acid include benzoic acid, salicylic acid, alkylbenzoic acid, alkylsalicylic acid, and cyclohexanecarboxylic acid.

  Examples of polybasic acids include dibasic acids, tribasic acids, and tetrabasic acids. The polybasic acid may be a chain polybasic acid or a cyclic polybasic acid. Further, in the case of a chain polybasic acid, it may be either linear or branched, and may be either saturated or unsaturated. As the chain polybasic acid, a chain dibasic acid having 2 to 16 carbon atoms is preferable. Specifically, for example, ethanedioic acid, propanedioic acid, linear or branched butanedioic acid, linear Or branched pentanedioic acid, linear or branched hexanedioic acid, linear or branched heptanedioic acid, linear or branched octanedioic acid, linear or branched nonane diacid Acid, linear or branched decanedioic acid, linear or branched undecanedioic acid, linear or branched dodecanedioic acid, linear or branched tridecanedioic acid, linear or Branched tetradecanedioic acid, linear or branched heptadecanedioic acid, linear or branched hexadecanedioic acid, linear or branched hexenedioic acid, linear or branched heptenedioic acid Linear or branched octene diacid, linear or branched nonene diacid, linear or branched Branched decenedioic acid, linear or branched undecenedioic acid, linear or branched dodecenedioic acid, linear or branched tridecenedioic acid, linear or branched tetradecenedioic acid And linear or branched heptadecene diacid, linear or branched hexadecene diacid, alkenyl succinic acid, and mixtures thereof. As the cyclic polybasic acid, 1,2-cyclohexanedicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid alicyclic dicarboxylic acid, phthalic acid or other aromatic dicarboxylic acid, trimellitic acid or other aromatic Examples thereof include aromatic tetracarboxylic acids such as tricarboxylic acid and pyromellitic acid.

  Examples of the molybdenum salt of the alcohol include a salt of a molybdenum compound not containing sulfur as exemplified in the description of the molybdenum-amine complex and an alcohol. The alcohol may be any of monohydric alcohol, polyhydric alcohol, partial ester or partial ether compound of polyhydric alcohol, nitrogen compound having a hydroxyl group (alkanolamide and the like), and the like. Molybdic acid is a strong acid and forms an ester by reaction with alcohol. The ester of molybdic acid and alcohol is also included in the molybdenum salt of alcohol in the present invention.

  As the monohydric alcohol, those having 1 to 24 carbon atoms, preferably 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms are usually used. Such alcohols may be linear or branched, and saturated. Or may be unsaturated. Specific examples of the alcohol having 1 to 24 carbon atoms include methanol, ethanol, linear or branched propanol, linear or branched butanol, linear or branched pentanol, and linear Linear or branched hexanol, linear or branched heptanol, linear or branched octanol, linear or branched nonanol, linear or branched decanol, linear or branched Undecanol, linear or branched dodecanol, linear or branched tridecanol, linear or branched tetradecanol, linear or branched pentadecanol, linear or branched hexadecane Decanol, linear or branched heptadecanol, linear or branched octadecanol, linear or branched nonadecanol, linear or branched icosa Lumpur, linear or branched Hen'ikosanoru, linear or branched Torikosanoru, such as linear or branched tetracosanol, and mixtures thereof.

  Moreover, as a polyhydric alcohol, the thing of 2-10 valence is preferable, Preferably it is 2-6 valence. Specific examples of the divalent to 10-valent polyhydric alcohol include, for example, ethylene glycol, diethylene glycol, polyethylene glycol (3 to 15 mer of ethylene glycol), propylene glycol, dipropylene glycol, polypropylene glycol (polypropylene glycol 3 15-mer), 1,3-propanediol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,2-propanediol, 2-methyl-1, Dihydric alcohols such as 3-propanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5-pentanediol, neopentylglycol; glycerin, polyglycerin (glycerin 2 ~ 8-mer such as diglycerin, g Glycerin, tetraglycerin, etc.), trimethylol alkanes (trimethylol ethane, trimethylol propane, trimethylol butane, etc.) and their 2- to 8-mer, pentaerythritol and their 2- to 4-mer, 1,2,4- Butanetriol, 1,3,5-pentanetriol, 1,2,6-hexanetriol, 1,2,3,4-butanetetrol, sorbitol, sorbitan, sorbitol glycerin condensate, adonitol, arabitol, xylitol, mannitol, etc. A polyhydric alcohol of xylose, arabinose, ribose, rhamnose, glucose, fructose, galactose, mannose, sorbose, cellobiose, maltose, isomaltose, trehalose, sucrose, and a mixture thereof. It is below.

  Examples of the partial ester of the polyhydric alcohol include compounds in which a part of the hydroxyl group of the polyhydric alcohol exemplified in the description of the polyhydric alcohol has been hydrocarbyl esterified, among which glycerin monooleate and glycerin dioleate. Sorbitan monooleate and sorbitan diolate are preferred.

  Moreover, as the partial ether of the polyhydric alcohol, an ether bond is formed by condensation of polyhydric alcohols, a compound in which a part of the hydroxyl groups of the polyhydric alcohol exemplified in the description of the polyhydric alcohol is hydrocarbyl etherified. Compounds (such as sorbitan condensates).

  Examples of the nitrogen compound having an alcoholic hydroxyl group include alkanolamines in which the amino group of alkanolamine is amidated in addition to the alkanolamines already mentioned above as examples of amine compounds, lauryl diethanolamide, myristyl diethanolamide, Examples include palmityl diethanolamide, stearyl diethanolamide, oleyl diethanolamide, and the like.

  In the lubricating oil composition of the present invention, the organic molybdenum compound as the component (B) may be used singly or in combination of two or more, and the amount of the lubricating oil composition Based on the total amount, in terms of molybdenum element, it is preferably 0.001% by mass or more, more preferably 0.003% by mass or more, still more preferably 0.01% by mass or more, and preferably 0.1% by mass. Hereinafter, it is more preferably 0.06% by mass or less, and still more preferably 0.04% by mass or less. When the content is 0.001% by mass in terms of molybdenum element, the corrosion prevention performance is not sufficiently exerted, and even if the content exceeds 0.1% by mass, an effect commensurate with the increase in content tends not to be obtained.

  As the ashless dispersant, any ashless dispersant used in lubricating oils can be used. For example, at least one linear or branched alkyl group or alkenyl group having 40 to 400 carbon atoms is included in the molecule. And nitrogen-containing compounds or derivatives thereof. Examples of the nitrogen-containing compound herein include succinimide, benzylamine, polyamine, Mannich base and the like, and derivatives thereof include boron compounds such as boric acid and borate, (thio) Examples thereof include phosphorus compounds such as phosphoric acid and (thio) phosphate, organic acids, derivatives obtained by reacting hydroxy (poly) oxyalkylene carbonate, and the like. In the present invention, one or two or more arbitrarily selected from these can be blended. The alkyl group or alkenyl group has 40 to 400 carbon atoms, preferably 60 to 350 carbon atoms. When the carbon number of the alkyl group or alkenyl group is less than 40, the solubility of the compound in the lubricating base oil decreases. On the other hand, when the carbon number of the alkyl group or alkenyl group exceeds 400, the low temperature of the lubricating oil composition Since fluidity | liquidity deteriorates, it is unpreferable respectively. This alkyl group or alkenyl group may be linear or branched, but specifically, preferred are derived from olefin oligomers such as propylene, 1-butene and isobutylene, and co-oligomers of ethylene and propylene. And a branched alkyl group and a branched alkenyl group. In the present invention, among these ashless dispersants, a branched alkyl group or alkenyl group having a number average molecular weight of 700 to 3500, preferably 1000 to 2000, more preferably 1200 to 1500, particularly a poly (iso) butenyl group. It is desirable to have a succinimide and / or a boron compound derivative thereof. Even when the unmodified succinimide is used, a sufficient lead corrosion prevention effect can be obtained when the component (A) or the component (A) and the component (B) are used in combination, but a boron compound derivative is used. Most preferred.

  In the present invention, the content of the ashless dispersant is not particularly limited, but is usually 0.1 to 20% by mass, preferably 3 to 15% by mass based on the total amount of the composition. Further, when a boron compound derivative of succinimide is contained as an ashless dispersant, the amount of boron is not particularly limited, but it should be contained so that the amount of boron is 0.005% by mass or more based on the total amount of the composition. More preferably, it is 0.01% by mass or more, particularly preferably 0.02% by mass or more. When the content of the boron compound derivative is increased, there is a concern about the influence on the sealing material and the increase in sulfated ash content. Therefore, the content is preferably 0.2% by mass or less as a boron amount, more preferably 0.1% by mass or less, further preferably 0.08% by mass or less, and further preferably 0.06% by mass or less. More preferably, it is 0.04 mass% or less.

  The antioxidant in the present invention may be any ashless antioxidant such as a phenolic antioxidant or amine antioxidant or an organic metal antioxidant that is generally used in lubricating oils. It can be used. By adding an antioxidant, the antioxidant property of the lubricating oil composition can be further enhanced, and not only the corrosion or corrosion wear prevention performance of the lead-containing metal of the composition of the present invention is enhanced, but also the base number maintenance property is further enhanced. be able to.

  Examples of phenolic antioxidants include 4,4′-methylenebis (2,6-di-tert-butylphenol), 4,4′-bis (2,6-di-tert-butylphenol), 4,4 ′. -Bis (2-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 4,4′-butylidenebis (3-methyl-6-tert-butylphenol), 4,4′-isopropylidenebis (2,6-di-tert-butylphenol), 2,2′-methylenebis (4-methyl-6) -Nonylphenol), 2,2'-isobutylidenebis (4,6-dimethylphenol), 2,2'-methylenebis (4-methyl) 6-cyclohexylphenol), 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,4-dimethyl-6-tert-butylphenol, 2, 6-di-tert-α-dimethylamino-p-cresol, 2,6-di-tert-butyl-4 (N, N′-dimethylaminomethylphenol), 4,4′-thiobis (2-methyl-6) -Tert-butylphenol), 4,4'-thiobis (3-methyl-6-tert-butylphenol), 2,2'-thiobis (4-methyl-6-tert-butylphenol), bis (3-methyl-4- Hydroxy-5-tert-butylbenzyl) sulfide, bis (3,5-di-tert-butyl-4-hydroxybenzyl) sulfide 2,2′-thio-diethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], tridecyl-3- (3,5-di-tert-butyl-4-hydroxy Phenyl) propionate, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) ) Propionate, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 3-methyl-5-tert-butyl-4-hydroxyphenyl substituted fatty acid esters and the like are preferable examples. Can do. You may use these in mixture of 2 or more types.

  Examples of amine-based antioxidants include phenyl-α-naphthylamine, alkylphenyl-α-naphthylamine, and dialkyldiphenylamine. You may use these in mixture of 2 or more types.

  You may mix | blend the said phenolic antioxidant, amine-type antioxidant, and organometallic antioxidant in combination.

  When the antioxidant is contained in the lubricating oil composition of the present invention, the content thereof is usually 20% by mass or less, preferably 10% by mass or less, more preferably 5% by mass based on the total amount of the lubricating oil composition. % Or less. When the content exceeds 20% by mass, it is not preferable because sufficient performance corresponding to the blending amount cannot be obtained. On the other hand, the content thereof is preferably 0.1% by mass or more based on the total amount of the lubricating oil composition in that the corrosion or corrosion wear prevention performance of the lead-containing metal material can be maintained for a longer period of time. Preferably it is 1 mass% or more, Most preferably, it is 1.5 mass% or more. In the present invention, by using the component (A) and the component (B) in combination, the content of the antioxidant can be suppressed to 1.5% by mass or less, and a cost-effective composition can be obtained.

  As the friction modifier, any compound usually used as a friction modifier for lubricating oils can be used, for example, sulfurized molybdenum dithiocarbamate or sulfurized oxymolybdenum dithiocarbamate, sulfurized molybdenum dithiophosphate or sulfurized oxymolybdenum dithiophosphate, Molybdenum-based friction modifier such as molybdenum disulfide, an amine compound having at least one alkyl group or alkenyl group having 6 to 30 carbon atoms, particularly a linear alkyl group or linear alkenyl group having 6 to 30 carbon atoms in the molecule Ashless friction modifiers such as fatty acid ester, fatty acid amide, fatty acid, aliphatic alcohol, aliphatic ether, hydrazide (oleyl hydrazide, etc.), semicarbazide, urea, ureido, biuret, etc., usually 0.1-5 mass % In the range of It is a function.

  As the anti-wear agent other than zinc dithiophosphate, any anti-wear agent generally used in lubricating oil, such as phosphorus-containing anti-wear agent other than zinc dithiophosphate, sulfur-containing anti-wear agent or boron-containing anti-wear agent, is used. Can be used without restriction.

  The phosphorus-containing antiwear agent is not particularly limited as long as it is an antiwear agent containing phosphorus in the molecule.

  The phosphorus-containing antiwear agent in the present invention includes a phosphorus compound represented by the general formula (12), a phosphorus compound represented by the general formula (13), and metal salts thereof, amine salts thereof or derivatives thereof. It is preferably at least one compound selected from the group consisting of

（一般式（１２）において、Ｘ^１、Ｘ^２及びＸ^３は、それぞれ個別に酸素原子又は硫黄原子を示し、Ｒ²²、Ｒ²³及びＲ²⁴は、それぞれ個別に水素原子又は炭素数１〜３０の炭化水素基を示す。）

(In General formula (12), X < ¹ >, X < ² > and X < ³ > show an oxygen atom or a sulfur atom each independently, R < ²² >, R <^23> and R < ²⁴ > are respectively hydrogen atom or carbon numbers 1-30. Represents a hydrocarbon group.)

（一般式（１３）において、Ｘ^４、Ｘ^５、Ｘ^６及びＸ^７は、それぞれ個別に酸素原子又は硫黄原子（Ｘ^４、Ｘ^５及びＸ^６の１つ又は２つが単結合又は（ポリ）オキシアルキレン基でもよい）を示し、Ｒ²⁵、Ｒ²⁶及びＲ²⁷は、それぞれ個別に水素原子又は炭素数１〜３０の炭化水素基を示す。）

(In General Formula (13), X ⁴ , X ⁵ , X ⁶ and X ⁷ are each independently an oxygen atom or a sulfur atom (one or two of X ⁴ , X ⁵ and X ⁶ are single bonds or (poly) R ²⁵ , R ²⁶ and R ²⁷ are each independently a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms.)

Specific examples of the hydrocarbon group having 1 to 30 carbon atoms represented by R ^{22 to} R ²⁷ include an alkyl group, a cycloalkyl group, an alkenyl group, an alkyl-substituted cycloalkyl group, an aryl group, and an alkyl-substituted aryl group. And arylalkyl groups.

  Examples of the alkyl group include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, and the like. Group, hexadecyl group, heptadecyl group, octadecyl group and other alkyl groups (these alkyl groups may be linear or branched).

  As said cycloalkyl group, C5-C7 cycloalkyl groups, such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, can be mentioned, for example. Examples of the alkylcycloalkyl group include a methylcyclopentyl group, a dimethylcyclopentyl group, a methylethylcyclopentyl group, a diethylcyclopentyl group, a methylcyclohexyl group, a dimethylcyclohexyl group, a methylethylcyclohexyl group, a diethylcyclohexyl group, a methylcycloheptyl group, Examples thereof include an alkylcycloalkyl group having 6 to 11 carbon atoms such as a dimethylcycloheptyl group, a methylethylcycloheptyl group, and a diethylcycloheptyl group (the substitution position of the alkyl group with the cycloalkyl group is also arbitrary).

  Examples of the alkenyl group include butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl, heptadecenyl, An alkenyl group such as an octadecenyl group (these alkenyl groups may be linear or branched, and the position of the double bond is also optional).

  As said aryl group, aryl groups, such as a phenyl group and a naphthyl group, can be mentioned, for example. Examples of the alkylaryl group include tolyl group, xylyl group, ethylphenyl group, propylphenyl group, butylphenyl group, pentylphenyl group, hexylphenyl group, heptylphenyl group, octylphenyl group, nonylphenyl group, and decylphenyl. A C7-C18 alkylaryl group such as a group, undecylphenyl group, dodecylphenyl group, etc. (the alkyl group may be linear or branched, and the substitution position on the aryl group is arbitrary) Can do.

  Examples of the arylalkyl group include arylalkyl groups having 7 to 12 carbon atoms such as benzyl group, phenylethyl group, phenylpropyl group, phenylbutyl group, phenylpentyl group, and phenylhexyl group. It may be branched).

The hydrocarbon group having 1 to 30 carbon atoms represented by R ^{22 to} R ²⁷ is preferably an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 24 carbon atoms, and more preferably 3 carbon atoms. -18, more preferably an alkyl group having 4 to 12 carbon atoms.

As a phosphorus compound represented by General formula (12), the following phosphorus compounds can be mentioned, for example.
Phosphorous acid, monothiophosphorous acid, dithiophosphorous acid, trithiophosphorous acid; phosphorous acid monoester having one hydrocarbon group having 1 to 30 carbon atoms, monothiophosphorous acid monoester, dithiophosphorous acid Monoester, trithiophosphite monoester; Phosphite diester, monothiophosphite diester, dithiophosphite diester, trithiophosphite diester having two hydrocarbon groups having 1 to 30 carbon atoms; Phosphorous acid triesters, monothiophosphite triesters, dithiophosphite triesters, trithiophosphite triesters having three 1-30 hydrocarbon groups; and mixtures thereof.

In the present invention, X ^{1 to} X ³ in the general formula (12) are excellent in preventing copper corrosion or corrosive wear and improving long drain performance such as high-temperature cleanability, oxidation stability, and base number maintenance. It is preferable that two or more are oxygen atoms, and it is particularly preferable that all of them are oxygen atoms.

As a phosphorus compound represented by General formula (13), the following phosphorus compounds can be mentioned, for example.
Phosphoric acid, monothiophosphoric acid, dithiophosphoric acid, trithiophosphoric acid, tetrathiophosphoric acid; phosphoric acid monoester having one hydrocarbon group having 1 to 30 carbon atoms, monothiophosphoric acid monoester, dithiophosphoric acid monoester, trithiophosphoric acid monoester, Tetrathiophosphoric acid monoester; phosphoric acid diester having two hydrocarbon groups having 1 to 30 carbon atoms, monothiophosphoric acid diester, dithiophosphoric acid diester, trithiophosphoric acid diester, tetrathiophosphoric acid diester; hydrocarbon having 1 to 30 carbon atoms Phosphoric acid triester having 3 groups, monothiophosphoric acid triester, dithiophosphoric acid triester, trithiophosphoric acid triester, tetrathiophosphoric acid triester; phosphonic acid having 1 to 3 hydrocarbon groups having 1 to 30 carbon atoms, Phosphonic acid monoesters, Phosphonic acid diester; Phosphorus compound having a (poly) oxyalkylene group having 1 to 4 carbon atoms; Phosphorus such as a reaction product of β-dithiophosphorylated propionic acid or dithiophosphoric acid and olefin cyclopentadiene or (methyl) methacrylic acid Derivatives of compounds; and mixtures thereof.

In the present invention, X ^{4 to} X ⁷ in the general formula (13) are excellent in preventing copper corrosion or corrosive wear and improving long drain performance such as high temperature cleanliness, oxidation stability, and base number maintenance. 2 or more are preferably oxygen atoms, more preferably 3 or more are oxygen atoms, and particularly preferably all of them are oxygen atoms. One or two of X ⁴ , X ⁵ and X ⁶ may be a single bond or a (poly) oxyalkylene group.

  As a salt of the phosphorus compound represented by the general formula (12) or (13), the phosphorus compound may be a metal base such as a metal oxide, a metal hydroxide, a metal carbonate, or a metal chloride, ammonia, 1 to 1 carbon atoms. Examples thereof include salts obtained by allowing a nitrogen compound such as an amine compound having only 30 hydrocarbon groups or hydroxyl group-containing hydrocarbon groups in the molecule to act to neutralize part or all of the remaining acidic hydrogen.

Specific 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 barium, zinc, copper, iron, lead, nickel, silver and manganese. And heavy metals such as molybdenum.
Among these, alkaline earth metals such as calcium and magnesium and zinc are preferable.

  The structure of the metal salt of the phosphorus compound differs depending on the valence of the metal and the number of OH groups or SH groups of the phosphorus compound. Therefore, the structure is not limited at all. For example, 1 mol of zinc oxide and phosphoric acid diester When 2 moles (one OH group) are reacted, a compound having a structure represented by the following general formula (14) is considered to be obtained as a main component, but polymerized molecules also exist. It is done.

  For example, when 1 mol of zinc oxide and 1 mol of phosphoric acid monoester (having two OH groups) are reacted, a compound having a structure represented by the following general formula (15) is considered to be obtained as a main component. However, polymerized molecules are also thought to exist.

  Specific examples of the nitrogen compound include ammonia, monoamine, diamine, and polyamine. More specifically, methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecylamine , Hexadecylamine, heptadecylamine, octadecylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, diundecylamine, didodecylamine, ditridecylamine Decylamine, ditetradecylamine, dipentadecylamine, dihexadecylamine, diheptadecylamine, dioctadecylamine, methyl ethyl Alkylamines having an alkyl group having 1 to 30 carbon atoms such as amine, methylpropylamine, methylbutylamine, ethylpropylamine, ethylbutylamine, and propylbutylamine (these alkyl groups may be linear or branched); Alkenyl amines having 2 to 30 carbon atoms such as ethenylamine, propenylamine, butenylamine, octenylamine, and oleylamine (these alkenyl groups may be linear or branched); methanolamine, ethanolamine, propanolamine , Butanolamine, pentanolamine, hexanolamine, heptanolamine, octanolamine, nonanolamine, methanol ethanolamine, methanol propanolamine, methanol butanol amine Alkanolamines having 1 to 30 carbon atoms such as ethanolpropanolamine, ethanolbutanolamine, and propanolbutanolamine (these alkanol groups may be linear or branched); methylenediamine, ethylenediamine, Alkylene diamine having 1-30 carbon atoms such as propylene diamine and butylene diamine; polyamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine; undecyldiethylamine, undecyldiethanolamine, dodecyldipropanol Amine, oleyldiethanolamine, oleylpropylenediamine, stearyltetraethylenepentamine, etc. Examples thereof include compounds having an alkyl group or alkenyl group having 8 to 20 carbon atoms in the amine and heterocyclic compounds such as N-hydroxyethyloleylimidazoline; alkylene oxide adducts of these 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, dimethyldodecylamine, tridecylamine, heptadecylamine, octadecylamine, oleylamine and stearylamine (these are A preferred example is a straight chain or a branched chain.

Examples of the phosphorus-containing antiwear agent include metal salts of phosphorus compounds in which X ¹ , X ² and X ³ in the general formula (12) are all oxygen atoms, and X ⁴ , X ⁵ , X ⁶ and X in the general formula (13). ^At least one compound selected from the group consisting of metal salts of phosphorus compounds in which ⁷ is an oxygen atom (one or two of X ⁴ , X ⁵ and X ⁶ may be a single bond or a (poly) oxyalkylene group) It is preferable in that it is excellent in oxidation stability, long drain properties such as high temperature cleanliness, low friction properties and the like.

Further, the phosphorus-containing antiwear agent is such that all of X ⁴ , X ⁵ , X ⁶ and X ^{7 in} the general formula (13) are oxygen atoms (one or two of X ⁴ , X ⁵ and X ⁶ are single bonds or ( Poly) oxyalkylene groups), and R ²⁵ , R ²⁶ and R ²⁷ are each a phosphorus compound having a hydrocarbon group of 1 to 30 carbon atoms, such as oxidation stability and high-temperature cleanliness It is preferable in that it has excellent long draining properties, and further enables low friction and further ashing.

  Among these components, a salt of a phosphite diester having two alkyl groups or aryl groups having 3 to 18 carbon atoms and zinc or calcium, an alkyl group or aryl group having 3 to 18 carbon atoms, preferably carbon number Phosphorous acid triesters having 3 alkyl groups of 6 to 12; monoesters of phosphoric acid having one alkyl group or aryl group having 3 to 18 carbon atoms and zinc or calcium; 3 to 18 carbon atoms Salt of diester of phosphoric acid having two alkyl groups or aryl groups and zinc or calcium, salt of phosphonic acid monoester having two alkyl groups or aryl groups having 1 to 18 carbon atoms, zinc or calcium, carbon number Phosphoric acid triester having 3 to 18 alkyl groups or aryl groups, preferably 3 to 12 carbon atoms, alkyl having 1 to 18 carbon atoms Or it is preferably an aryl group is a 3 having a phosphonic acid diester. These components can be arbitrarily blended in one kind or two or more kinds.

  The content of the phosphorus-containing antiwear agent in the lubricating oil composition of the present invention is not particularly limited, but is 0.005% by mass or more, preferably 0.01% by mass in terms of phosphorus element based on the total amount of the composition. %, Particularly preferably 0.02% by mass or more, while the content thereof is preferably 0.1% by mass or less, more preferably 0.08% by mass or less, particularly preferably 0.05% by mass or less. It is. When the content of the phosphorus-containing antiwear agent is less than 0.005% by mass as the phosphorus element, there is no effect on the antiwear property, which is not preferable. On the other hand, the content is 0.1% by mass as the phosphorus element. In the case of exceeding 1, it is not preferable because there is a concern about an adverse effect on the exhaust gas aftertreatment device. In addition, when containing sulfur such as zinc dithiophosphate and a phosphorus-containing wear inhibitor as a phosphorus-containing wear inhibitor, these contents are based on the total amount of the composition in terms of being able to suppress copper corrosion or corrosive wear. As a conversion amount, 0.06% by mass or less, preferably 0.05% by mass or less, more preferably 0.04% by mass or less, or a lubricating oil composition having a low sulfur content and a long drain which does not contain these. be able to.

  Examples of the sulfur-containing antiwear agent include sulfur-containing compounds such as disulfides, sulfurized olefins, sulfurized fats and oils, dithiocarbamate, and zinc dithiocarbamate. These sulfur-containing compounds can be contained in the composition of the present invention in the range of 0.005 to 5% by mass as long as the total sulfur content of the composition is not more than the specified amount of the present invention. The content of these is 0.15% by mass or less, preferably 0.1% by mass or less, in particular 0.05% by mass or less, or does not contain these, reducing sulfur and A lubricating oil composition having a long drain can be obtained.

  As the viscosity index improver, specifically, a so-called non-dispersed viscosity index improver such as a polymer or copolymer of one or more monomers selected from various methacrylates or a hydrogenated product thereof, Or a so-called dispersion-type viscosity index improver obtained by copolymerizing various methacrylic esters containing a nitrogen compound, a non-dispersion type or a dispersion type ethylene-α-olefin copolymer (propylene, 1-butene, 1 -Pentene, etc.)) or a hydride thereof, polyisobutylene or a hydrogenated product thereof, a hydride of a styrene-diene copolymer, a styrene-maleic anhydride copolymer, and a polyalkylstyrene.

  The molecular weight of these viscosity index improvers needs to be selected in consideration of shear stability. Specifically, the number average molecular weight of the viscosity index improver is usually 5,000 to 1,000,000, preferably 100,000 to 900,000 in the case of dispersed and non-dispersed polymethacrylates, for example. In the case of polyisobutylene or a hydride thereof, usually 800 to 5,000, preferably 1,000 to 4,000, and in the case of an ethylene-α-olefin copolymer or a hydride thereof, usually 800 to 500. 3,000, preferably 3,000 to 200,000 are used.

  Further, among these viscosity index improvers, when an ethylene-α-olefin copolymer or a hydride thereof is used, a lubricating oil composition particularly excellent in shear stability can be obtained. One or two or more compounds arbitrarily selected from the above viscosity index improvers can be contained in any amount. The content of the viscosity index improver is usually 0.1 to 20% by mass based on the lubricating oil composition.

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

  Examples of the rust inhibitor include petroleum sulfonate, alkylbenzene sulfonate, dinonylnaphthalene sulfonate, alkenyl succinic acid ester, and polyhydric alcohol ester.

  Examples of the demulsifier include polyalkylene glycol nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, and polyoxyethylene alkyl naphthyl ether.

  Examples of metal deactivators include imidazoline, pyrimidine derivatives, alkylthiadiazoles, mercaptobenzothiazoles, benzotriazoles or derivatives thereof, 1,3,4-thiadiazole polysulfide, 1,3,4-thiadiazolyl-2,5-bis. Examples include dialkyldithiocarbamate, 2- (alkyldithio) benzimidazole, and β- (o-carboxybenzylthio) propiononitrile.

  Examples of the antifoaming agent include silicone, fluorosilicol, and fluoroalkyl ether.

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

  Note that the lubricating oil composition of the present invention corrodes or corrodes lead-containing metal materials by optimizing the metal-based detergent even if the zinc dithiophosphate content is 0.08 mass% or less as the phosphorus content. It is a composition that can suppress wear, and can be a low-sulfur lubricating oil composition having a total sulfur content of 0.3% by mass or less as required. By selecting a lubricating base oil and various additives, Lubricating oil composition in which the total sulfur content of the composition is 0.2% by mass or less, more preferably 0.1% by mass or less, particularly 0.05% by mass or less or 0.01% by mass or less, and substantially no sulfur is contained. It is also possible to get things.

  In addition, the lubricating oil composition of the present invention can adjust the content of the metal-containing additive to make the sulfated ash content of the composition 1.0% by mass or less. From the viewpoint of suppressing deposition in the combustion chamber, it is preferably 0.8% by mass, more preferably 0.6% by mass or less, and particularly preferably 0.5% by mass or less.

  The lubricating oil composition of the present invention has low sulfur and is excellent not only in corrosion or corrosion wear resistance of lead-containing metal materials, but also in low friction properties, long drain properties (oxidation stability, base number maintenance properties, etc.) and Excellent high-temperature cleanliness, can be preferably used as a lubricating oil for internal combustion engines, and low sulfur, low phosphorus or non-phosphorus, low ash lubricating oil, especially with an exhaust gas aftertreatment device Suitable for institutions. In addition, low sulfur fuel, for example, fuel having a sulfur content of 50 ppm by mass or less, more preferably 30 ppm by mass or less, particularly preferably 10 ppm by mass or less (eg gasoline, light oil, kerosene, alcohol, dimethyl ether, LPG, natural gas, etc. Is suitable for lubricating oil for internal combustion engines. In particular, it can be particularly preferably used as a lubricating oil for a diesel engine or a gas engine having a lead-containing sliding material. Among these, it can be particularly preferably used as a lubricating oil for gas engines.

  The lubricating oil composition suitable for contact with the lead-containing metal material of the present invention includes lubricating oil for driving systems such as automatic or manual transmissions, grease, wet brake oil, hydraulic hydraulic oil, turbine oil, compressor oil. Also, it can be suitably used as a lubricating oil such as bearing oil and refrigerator oil.

  The contents 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.

(Examples 1-4, Comparative Examples 1-4)
As shown in Table 1, lubricating oil compositions of the present invention (Examples 1 to 4) and comparative lubricating oil compositions (Comparative Examples 1 to 4) were prepared.

  The following evaluation tests were performed on the obtained compositions.

(Change in elution amount of lead by NOx absorption test over time)
The time course of the amount of lead elution when NOx gas was blown into test oil containing lead pieces under the conditions (140 ° C., NOx: 1185 ppm) in accordance with 1992, 10, 465, Japan Tribology Conference Proceedings. It was measured. It shows that lead corrosion can be suppressed, so that there is little lead elution amount. It should be noted that the forced deterioration by the NOx absorption test makes it possible to confirm in a short time the influence of deterioration products on the lead corrosion due to the deterioration of the lubricating oil, particularly the deterioration of the lubricating oil for internal combustion engines.

The compositions of Comparative Examples 1 to 4 in Table 1 are compositions that do not contain the dialkyl salicylate that is the component (A) of the present invention, but instead contain another metallic detergent. The compositions of Comparative Examples 1 to 3 containing a salicylate detergent (monoalkyl type) other than the component (A) of the present invention and the composition of Comparative Example 4 containing only a sulfonate detergent are the components (A) of the present invention. Compared with Examples 1 to 4 containing dialkyl salicylate, the amount of elution of lead is very large. From this, it can be seen that the dialkyl salicylate component (A) is effective for suppressing the amount of lead elution.

Claims (2)

Lubricating oil composition which is in contact with the lead-containing metal material without containing 0.08% by mass or less of zinc dithiophosphate as a phosphorus amount on the basis of the total amount of the composition, based on the total amount of the composition, which is a component (A) And a dialkyl salicylate represented by the general formula (1) and / or a (over) basic salt thereof.

In the general formula (1), R ¹ and R ² may be the same or different and each represents a hydrocarbon group having 1 to 40 carbon atoms, and the hydrocarbon group may contain oxygen or nitrogen. M represents an alkali metal or an alkaline earth metal, and n represents 1 or 2 depending on the valence of the metal. In the lubricating base oil, based on the total amount of the composition, zinc dithiophosphate is not contained or contained in 0.08% by mass or less as phosphorus, (A) a dialkyl salicylate represented by the general formula (1), and / or its (5) Lubricating oil composition containing 0.005 to 5% by mass of a basic salt as a metal amount and (B) 0.001 to 0.1% by mass of an organomolybdenum compound as a molybdenum amount object.