KR20160138020A - Lubricating oil composition for an internal combustion engine - Google Patents

Abstract

The lubricating oil composition for an internal combustion engine of the present invention is a lubricating oil composition for a internal combustion engine comprising (A) a lubricating base oil comprising a mineral oil and / or a synthetic oil, (B) a boron-containing alkenylsuccinic acid imide in an amount of 0.001 to 0.1% Boron-containing alkyl succinic acid imide, and Mw is 100,000 to 700,000, and Mw / X is 30,000 or more when the weight-average molecular weight is Mw and the average carbon number of the alkyl group measured by ¹³ C- (C) poly (meth) acrylate in an amount of 0.1 to 30 mass%.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a lubricating oil composition for internal combustion engines,

The present invention relates to a lubricating oil composition for an internal combustion engine.

BACKGROUND ART [0002] In an internal combustion engine used for an automobile or the like, a variety of demands have been made, such as small-size high output, fuel economy saving, exhaust gas regulation, and so on. Various additives such as a dispersant, an antioxidant, and a viscosity index improver are added.

Further, the engine oil is required to improve the performance from various viewpoints. For example, it may be required to suppress coking caused by carbonization of the engine oil, or to inhibit the elution of copper from engine parts. In response to these demands, for example, Patent Document 1 discloses the use of a hydrazide derivative having a specific structure as an additive in order to suppress copper elution. Patent Document 2 discloses that a specific molybdenum additive and a sulfurized fatty acid ester are used in combination in order to suppress coking.

Japanese Patent No. 4477337 Japanese Patent Application Laid-Open No. 2005-247995

However, in the internal combustion engine, high performance and high output have been advanced, and operating conditions have become harsh every year. Therefore, it is necessary to further increase the oxidation stability of the engine oil, and there is a higher demand for suppressing the drop of the base oil over a long period of time.

Further, for example, it is known that copper elution is apt to occur in a city operation in which a street is repeated. In addition, in recent years, in addition to the high-speed region, a high output using a turbocharger is also expected in a low-speed region such as a city driving, and it is expected that an engine equipped with a turbo mechanism will increase in the future. However, it is known that caulking tends to occur in a turbo mechanism-mounted engine.

Therefore, it is necessary to balance both the caulking and the copper elution in the engine oil.

However, the formulations disclosed in Patent Documents 1 and 2 are techniques for individually suppressing the caulking and the copper elution, respectively, so that it is difficult to effectively suppress both coking and copper elution while suppressing the drop of the base.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a lubricating oil composition for an internal combustion engine which suppresses the generation of base elution, caulking and copper elution in a balanced manner.

As a result of intensive studies, the inventors of the present invention have found that a combination of boron-containing succinic acid imide and poly (meth) acrylate having a weight average molecular weight (Mw) and a ratio of the average carbon number of alkyl groups in the side chain And the present invention has been accomplished. The present invention provides the following (1) to (9).

(1) a lubricant base oil (A) comprising a mineral oil and / or a synthetic oil,

(B) a boron-containing alkenylsuccinic acid imide and / or a boron-containing alkylsuccinic acid imide in an amount of 0.001 to 0.1% by mass in terms of a boron content based on the total amount of the composition,

Wherein Mw is 100,000 to 700,000, Mw / X is 30,000 or more, and 0.1 to 30% by mass, based on the total amount of the composition, based on the weight average molecular weight is Mw and the average carbon number of the alkyl group measured by ¹³ C- (C) a lubricating oil composition for an internal combustion engine containing poly (meth) acrylate.

(2) The lubricating oil composition for an internal combustion engine according to (1), wherein Mw / X is 30,000 to 200,000.

(3) The lubricating oil composition for internal combustion engines as described in (1) or (2), wherein (C) poly (meth) acrylate is non-dispersed.

(4) The lubricating oil composition for internal combustion engines as described in any one of (1) to (3), wherein (A) the viscosity index of the lubricating oil base oil is 90 or more.

(5) The lubricating oil composition for an internal combustion engine according to any one of (1) to (4), wherein the mineral oil has a paraffin content (% C _P ) of at least 60% by ring analysis.

(6) A lubricating oil composition for an internal combustion engine as described in any one of (1) to (5) above, which contains at least one selected from zinc dithiophosphate and (D) alkali metal detergent or alkaline earth metal detergent.

(7) A positive resist composition comprising (D) 0.01 to 0.15% by mass of zinc dithiophosphate in terms of trace, (E) 0.1 to 0.3% by mass of an alkali metal cleaner or an alkaline earth metal cleaner, (6). ≪ / RTI >

(8) The lubricating oil composition for an internal combustion engine as described in any one of (1) to (7), wherein the dynamic viscosity at 100 ° C is 4 to 17 mm ² / s.

(9) A lubricating oil composition comprising (A) a lubricating oil base oil comprising a mineral oil and / or a synthetic oil, wherein (B) 0.001 to 0.1% by mass of boron-containing alkenylsuccinic acid imide and / And (C) a poly (meth) acrylate in an amount of 0.1 to 30 mass% based on the total amount of the composition to prepare a lubricating oil composition for an internal combustion engine,

(C) a poly (meth) acrylate having an Mw of 100,000 to 700,000 and an Mw / X of 30,000 or more, wherein the weight average molecular weight is Mw and the average carbon number of the alkyl group measured by ¹³ C- A method for producing a lubricating oil composition for engines.

According to the present invention, it is possible to provide a lubricating oil composition for an internal combustion engine that suppresses the generation of base deterioration, occurrence of caulking, and occurrence of copper elution in a balanced manner.

Hereinafter, preferred embodiments of the present invention will be described in detail.

[Lubricating oil composition for internal combustion engine]

The lubricating oil composition for an internal combustion engine (hereinafter sometimes simply referred to as "lubricating oil composition") of the present invention is a lubricating oil composition for lubricating oil for internal combustion engines, which comprises (A) a lubricating oil base oil, (B) boron-containing alkenylsuccinic acid imide and / (Hereinafter sometimes simply referred to as "boron-containing succinic acid imide") and (C) poly (meth) acrylate. Hereinafter, each component will be described in more detail.

[(A) Lubricant base oil]

(A) The lubricating base oil may be any of mineral oil and synthetic oil conventionally used as a base oil of lubricating oil, and may be suitably selected from mineral oil and / or synthetic oil.

As the mineral oil, for example, a lubricating oil fraction obtained by vacuum distillation of an atmospheric pressure residue obtained by atmospheric distillation of crude oil is subjected to at least one treatment such as solvent deaeration, solvent extraction, hydrogenolysis, solvent degasification, contact dewaxing, Mineral oil or wax, or a lubricating oil base oil produced by isomerizing GTL WAX. Of these, mineral oils treated by hydrogenation purification are preferred. The mineral oil treated by the hydrogenation purification tends to have good% C _P and viscosity index to be described later.

Examples of the synthetic oil include polyalphaolefins such as polybutene, alpha-olefin homopolymers and copolymers (e.g., ethylene- alpha -olefin copolymer), such as polyol esters, dibasic acid esters, phosphoric acid esters , Various ethers such as polyphenylene ether, polyglycols, alkylbenzenes, alkylnaphthalenes, and lubricant base oils produced by isomerizing GTL WAX. Of these synthetic oils, polyalphaolefins and esters are particularly preferred, and a combination of these two is also suitably used as a synthetic oil.

In the present invention, as the lubricating oil base oil, one type of mineral oil may be used alone, or two or more kinds of mineral oils may be used in combination. In addition, one type of synthetic oil may be used, or two or more types may be used in combination. Further, at least one mineral oil and at least one synthetic oil may be used in combination.

The lubricant base oil (A) is a main component of the lubricating oil composition and is usually contained in an amount of 50 mass% or more, preferably 60 to 97 mass%, and more preferably 65 to 95 mass%, based on the whole amount of the lubricating oil composition .

(A) particularly limited to the viscosity of the lubricating oil base oil, but, it is preferable that the kinematic viscosity at 100 ℃ in the range of 1.0~20mm ² / s, more preferably in the range of 1.5~15mm ² / s, 2.0~13mm ² / s. ≪ / RTI > In the present invention, as described above, when the kinematic viscosity of the lubricant base oil (A) is set at a relatively low point, it becomes easy to realize fuel economy saving performance. In the present specification, the kinematic viscosity is measured by the method described in the following embodiments.

Further, the viscosity index of the lubricant base oil (A) is preferably 90 or more, more preferably 95 or more, and even more preferably 100 or more. The upper limit value of the viscosity index of the lubricating base oil is not particularly limited, but is preferably 170 or less, more preferably 160 or less, still more preferably 150 or less.

When the viscosity index of the lubricating base oil is in the above range, the viscosity characteristics of the lubricating oil composition are easily improved. On the other hand, in the present specification, the viscosity index is measured by the method described in the following embodiments.

The paraffin content (% C _P ) of the mineral oil is preferably 60% or more, and more preferably 65% or more. When the paraffin content is 60% or more, the oxidation stability of the base oil is improved, and the reduction of the base weight and the occurrence of caulking in the lubricating oil composition are suppressed. On the other hand, the measurement of the paraffin content (% C _P ) is as follows.

[(B) Boron-containing succinic acid imide]

Examples of (B) boron-containing succinic acid imides used in the present invention include boron compounds of alkenyl or alkyl succinic acid monoimide, alkenyl or boron compounds of alkyl succinic acid bisimide. Examples of the alkenyl or alkyl succinic acid monoimide include compounds represented by the following formula (1). Examples of the alkenyl or alkyl succinic acid bisimide include compounds represented by the following formula (2). In the present invention, by blending the component (B), the cleanliness of the composition is improved. Further, when used in combination with component (C), occurrence of caulking and copper elution can be suppressed.

In the above formulas (1) and (2), R ¹ , R ³ and R ⁴ are each an alkenyl group or an alkyl group and have a weight average molecular weight of preferably 500 to 3,000, more preferably 1,000 to 3,000 .

When the above-mentioned R ¹ , R ³ and R ^{4 have} a weight average molecular weight of 500 or more, solubility in base oil can be improved. If it is 3,000 or less, it is expected that the effect obtained by the present compound can be exerted properly. R ³ and R ⁴ may be the same or different.

R ² , R ⁵ and R ⁶ are each an alkylene group having 2 to 5 carbon atoms, and R ⁵ and R ⁶ may be the same or different. m represents an integer of 1 to 10, and n represents 0 or an integer of 1 to 10. Here, m is preferably 2 to 5, more preferably 3 to 4. When m is 2 or more, it is expected that the effect obtained by the present compound can be properly exerted. When m is 5 or less, solubility in base oil is further improved.

In the above formula (2), n is preferably 1 to 4, and more preferably 2 to 3. When n is 1 or more, it is expected that the effect obtained by the present compound can be properly exerted. When n is 4 or less, solubility in the base oil is further improved.

Examples of the alkenyl group include a polybutene group, a polyisobutylene group, and an ethylene-propylene copolymer. Examples of the alkyl group include those obtained by hydrogenating them. Examples of suitable alkenyl groups include a polybutene group and a polyisobutenyl group. As the polyurethane resin, a mixture of 1-butene and isobutene or a mixture of high-purity isobutene is suitably used. Representative examples of suitable alkyl groups include those obtained by hydrogenating polybutene diol or polyisobutylene diol.

The boron-containing succinic acid imide (B) can be prepared by a conventionally known method. For example, the polyolefin is reacted with maleic anhydride to form an alkenylsuccinic anhydride, and then further reacted with a boron compound such as a polyamine and a boron oxide such as boron oxide, boron boron, boric acid, boric acid anhydride, Lt; / RTI > by reaction with an intermediate. Monoimide or bisimide can be prepared by varying the ratio of alkenylsuccinic anhydride or alkylsuccinic anhydride to polyamine.

The boron-containing succinic acid imide (B) may also be obtained by treating an alkenyl or alkylsuccinic acid monoimide containing no boron, an alkenyl or an alkylsuccinic acid bisimide with the boron compound.

As the olefin monomer for forming the polyolefin, one or two or more kinds of? -Olefins having 2 to 8 carbon atoms can be used in combination, and a mixture of isobutene and 1-butene can be suitably used.

On the other hand, examples of the polyamines include monodiamines such as ethylenediamine, propylenediamine, butylenediamine and pentylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, diesters Methylethylene) triamine, dibutylenetriamine, tributylenetetramine and pentapentylenehexamine, and piperazine derivatives such as aminoethylpiperazine.

The component (B) is contained in an amount of 0.001 to 0.1% by mass in terms of a boron content based on the total amount of the composition. If it is less than 0.001% by mass, occurrence of caulking and copper elution becomes difficult to suppress. On the other hand, if it exceeds 0.1% by mass, precipitation will occur and it will be difficult to exert an effect suited to the compounding amount. From these viewpoints, the content of the component (B) is preferably 0.005 to 0.08% by mass, more preferably 0.010 to 0.06% by mass, in terms of the boron content based on the total amount of the composition.

Further, the mass ratio (B / N ratio) of boron to nitrogen in the component (B) is preferably 0.8 or more, more preferably 1.0 or more, and more preferably 1.1 or more. The upper limit of the B / N ratio is not particularly limited, but is preferably 2.0 or less, more preferably 1.5 or less, and even more preferably 1.3 or less. By setting the B / N ratio within the above range, the effect obtained by the present compound can be suitably exhibited.

On the other hand, the content of the component (B) is not particularly limited as long as the amount of the component (B) falls within the above range, but is generally from 0.1 to 10 mass%, preferably from 0.5 to 5 mass% 1 to 4% by mass.

[(C) poly (meth) acrylate]

(C) poly (meth) acrylate contained in the lubricating oil composition of the present invention has a weight average molecular weight of Mw and an average carbon number of an alkyl group measured by ¹³ C-NMR as X, and has Mw of 100,000 to 700,000 (Meth) acrylate having an Mw / X of 30,000 or more.

The alkyl group means all the alkyl groups present in the poly (meth) acrylate. For example, R < ⁷ > and R < ⁸ > , And when an alkyl group is bonded to COO- of (meth) acrylate via another substituent, it also includes such an alkyl group. The average carbon number means an arithmetic average value.

In the present invention, by containing the component (C) in addition to the component (B), elution of copper and occurrence of caulking in the lubricating oil composition can be balanced. Although the principle is not certain, it is estimated as follows. It is presumed that poly (meth) acrylate (hereinafter, also referred to as " PMA ") forms a complex with copper by decomposition or the like, and copper may be eluted from an alloy of parts such as a bearing part of an engine. When the PMA is structured to be easily entangled with each other, the amount of the PMA adhered to the surface of the engine metal is reduced, and as a result, the elution of copper is suppressed. In addition, when PMA is decomposed, the reactivity is increased, which is a factor, and it is easy to cause caulking or elution of copper. In the present invention, by the action of the component (B), the entanglement easiness of the PMA is promoted and the decomposition of the PMA is suppressed, whereby the elution of copper and the occurrence of caulking in the lubricating oil composition are balanced.

In the present invention, it is important to balance the size of the alkyl group of the side chain of MMA with the side chain of the PMA. In the case of having a small number of small alkyl groups on the side chain, the PMA tends to be entangled even with a relatively low Mw. On the other hand, , It is presumed that even with a relatively high Mw, PMA becomes difficult to be entangled. In addition, it is presumed that the PMA is liable to be entangled in the case of having a large alkyl group at a certain ratio or more in a side chain and a relatively high Mw, but decomposition of PMA is likely to occur. Therefore, when Mw / X is less than 30,000, the adhesion of PMA to the surface of the engine metal can not be sufficiently reduced, and further, decomposition of PMA tends to occur, making it difficult to suppress the elution of copper and the occurrence of caulking .

When the Mw is in a certain range, the reactivity of PMA is small even if many side chain alkyl groups have a certain size. On the other hand, when the Mw is more than 70,000, the reactivity of PMA increases even if there are many small alkyl groups in the side chain So that caulking or elution of copper can easily occur. If the molecular weight is less than 100,000, it is presumed that even if a small number of small alkyl groups are present in the side chain, entanglement becomes difficult, and the elution of copper can not be sufficiently suppressed.

Further, by containing the component (C) in which Mw and Mw / X are in a constant range, the oxidation stability is enhanced and the reduction of the base weight can be suppressed.

Mw / X is preferably in the range of 30,000 to 200,000, more preferably in the range of 30,000 to 130,000, and more preferably in the range of 3,000 to 1,000,000, in view of appropriately suppressing the dissolution of copper, More preferably 100,000.

The weight average molecular weight (Mw) is preferably 100,000 to 700,000, more preferably 150,000 to 600,000, and even more preferably 180,000 to 550,000.

(C) The poly (meth) acrylate is preferably a polymer of a polymerizable monomer comprising a (meth) acrylate monomer represented by the following formula (3).

In the formula (3), R ⁷ represents a hydrogen atom or a methyl group, and R ⁸ represents a linear or branched alkyl group having 1 to 200 carbon atoms. R ⁸ is preferably an alkyl group having 1 to 40 carbon atoms, more preferably an alkyl group having 1 to 28 carbon atoms, and still more preferably an alkyl group having 1 to 25 carbon atoms.

In the formula (3), R ⁸ is specifically a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, A hexadecyl group, a hexadecyl group, an octadecyl group, a nonadecyl group, an eicosyl group, a heneicosyl group, a docosyl group, a tricosyl group, a tetracosyl group, a pentacosyl group, Examples of the aryl group include a phenyl group, a naphthyl group, a naphthyl group, a naphthyl group, a naphthyl group, a naphthyl group, a naphthyl group, a naphthyl group, An aconyl group, a tetraconyl group and the like, and they may be linear or branched.

In the present invention, the component (C) is preferably a non-dispersion type. Specific examples of the non-dispersed poly (meth) acrylate include a homopolymer of a monomer represented by the formula (3) or a poly (meth) acrylate obtained by copolymerization of two or more thereof.

However, the (C) poly (meth) acrylate may be a dispersion type poly (meth) acrylate. As the dispersed poly (meth) acrylate, those obtained by copolymerizing a monomer represented by the formula (3) with at least one monomer selected from the following formulas (4) and (5) can be cited.

In the formula (4), R ⁹ represents a hydrogen atom or a methyl group, R ¹⁰ represents an alkylene group having 1 to 28 carbon atoms, E ¹ represents an amine having 1 to 2 nitrogen atoms and 0 to 2 oxygen atoms Or a heterocyclic residue, and a represents 0 or 1.

In formula (5), R ¹¹ represents a hydrogen atom or a methyl group, and E ² represents an amine residue or a heterocyclic residue containing 1 to 2 nitrogen atoms and 0 to 2 oxygen atoms.

Specific examples of the groups represented by E ¹ and E ² include a dimethylamino group, a diethylamino group, a dipropylamino group, a dibutylamino group, an anilino group, a toluidino group, a xylidino group, an acetylamino group, A pyrrolidinyl group, a pyrrolidinyl group, a piperidinyl group, a quinonyl group, a pyrrolidonyl group, a pyrrolidono group, an imidazolino group and a pyranino group, etc. Can be exemplified.

Preferable examples of the monomers represented by the formulas (4) and (5) include, specifically, dimethylaminomethyl methacrylate, diethylaminomethyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate , 2-methyl-5-vinylpyridine, morpholinomethyl methacrylate, morpholinoethyl methacrylate, N-vinylpyrrolidone, and mixtures thereof.

The copolymerization molar ratio of the monomer (M1) represented by the formula (3) to the copolymer of the monomer (M2) represented by the formula (4) and / or (5) is not particularly limited, but M1: M2 = 99: : 20, more preferably 98: 2 to 85: 15, and still more preferably 95: 5 to 90: 10.

In the component (C) of the present invention, the monomer represented by the above formula (3) is preferably contained in an amount of 70% by mass, more preferably 85% by mass or more, more preferably 90% Or more.

The component (C) may contain monomer units derived from monomers other than the above-mentioned formulas (3) to (5) within the range not contradictory to the object of the present invention. Generally, such a monomer component is about 10% by mass or less of the entire monomer component.

More specifically, the component (C) may be at least an alkyl (meth) acrylate monomer having an alkyl group of 1 to 4 carbon atoms and an alkyl (meth) acrylate monomer having an alkyl group of 12 to 40 carbon atoms, (Meth) acrylate monomer having an alkyl group of 1 to 4 carbon atoms, an alkyl (meth) acrylate monomer having an alkyl group of 5 to 11 carbon atoms, an alkyl (meth) acrylate monomer having an alkyl group of 12 to 40 carbon atoms Are copolymerized at least. Among these, preferred are those obtained by copolymerizing at least an alkyl (meth) acrylate monomer having 1 to 4 carbon atoms in the alkyl group and an alkyl (meth) acrylate monomer having 12 to 40 carbon atoms in the alkyl group, Includes at least a copolymer of a methyl (meth) acrylate monomer and an alkyl (meth) acrylate monomer having an alkyl group having from 16 to 25 carbon atoms.

The content of the (C) poly (meth) acrylate is 0.1 to 30% by mass based on the total amount of the composition. If the amount is less than 0.1% by mass, it is difficult to balance the generation of copper elution, the occurrence of caulking, and the drop of the base. When it exceeds 30 mass%, it is difficult to exhibit an effect suited to the content thereof. The content of the component (C) is preferably 0.3 to 25% by mass, and more preferably 0.5 to 10% by mass. On the other hand, the content of the component (C) means the content of the resin component thereof.

[(D) Zinc dithiophosphate]

The lubricating oil composition of the present invention may contain (D) zinc dithiophosphate. (D) zinc dithiophosphate, the anti-abrasion resistance can be improved and the oxidation stability can be improved. Examples of zinc dithiophosphate include compounds represented by the following formula (6).

R ¹² , R ¹³ , R ¹⁴ and R ¹⁵ in the formula (6) each independently represent a hydrocarbon group having 1 to 24 carbon atoms. Examples of the hydrocarbon group include a linear or branched alkyl group having 1 to 24 carbon atoms, 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 alkyl cycloalkyl group, An aryl group having 6 to 18 carbon atoms, a linear or branched alkylaryl group, and an arylalkyl group having 7 to 19 carbon atoms. Of these, an alkyl group is preferable.

As zinc dithiophosphate, specifically, zinc dialkyldithiophosphate is preferable, and among them, zinc secondary dialkyldithiophosphate is preferable.

The content of zinc dithiophosphate is more preferably 0.005 to 0.30 mass%, more preferably 0.01 to 0.15 mass% in terms of the total amount of the composition. Within the above range, the abrasion resistance and oxidation stability of the lubricating oil composition can be improved without affecting the cleanliness and caking resistance.

[(E) Metal-Based Cleaning Agent]

The lubricating oil composition may further contain (E) a metallic detergent composed of an alkali metal detergent or an alkaline earth metal detergent. (E) Containing a metal-based detergent makes it easy to suppress the generation of bases and the occurrence of caulking and copper elution while improving cleanliness.

Specifically, there may be mentioned one or more metal-based detergents selected from alkali metal sulfonates or alkaline earth metal sulfonates, alkali metal phenates or alkaline earth metal phenates, alkali metal salicylates or alkaline earth metal salicylates, have. Examples of the alkali metals include sodium, potassium, and alkaline earth metals such as magnesium and calcium. Sodium alkaline metals and magnesium and calcium alkaline earth metals are suitably used, and calcium is more preferred.

The alkali metal-based detergent or the alkaline earth metal-based detergent may be any of neutral, basic, and overbased, but it is preferably basic or overbased, and its infecting group is preferably 10 to 500 mgKOH / g, more preferably 150 to 450 mgKOH / g Is more preferable. On the other hand, the infectious agent is measured by perchloric acid method of JIS K-2501.

The metal-based cleaner (E) may be used alone, for example, in an amount of 150 to 450 mgKOH / g, but it is preferable to use an alkali metal cleaner or an alkaline earth metal cleaner with a transferring unit of 150 to 450 mgKOH / g, Or an alkaline earth metal-based detergent may be used in combination.

The content of the metal-based cleaning agent (E) is preferably 0.05 to 0.5 mass%, more preferably 0.1 to 0.3 mass%, in terms of the metal amount, with respect to the total amount of the composition. By containing these lower limit values or more, the base is lowered, but occurrence of caulking and copper elution can be more easily suppressed. Further, when the content is less than the upper limit value, an effect suited to the content can be exhibited.

It is more preferable that the lubricating oil composition contains 0.01 to 0.15 mass% of (D) zinc dithiophosphate in terms of the total amount of the composition and 0.1 to 0.3 mass% of the metal-based cleaner (E) .

[Other ingredients]

The lubricating oil composition may contain boron-free succinic acid imide in addition to (B) boron-containing succinic acid imide. The boron-free succinic acid imide is an alkenyl succinic acid imide and / or an alkyl succinic acid imide which does not contain boron. The alkenylsuccinic acid imides and / or alkylsuccinic acid imides include the above-mentioned alkenyl or alkylsuccinic acid monoimides, or alkenyl or alkylsuccinic acid bisimides.

The boron-free succinic acid imide is not particularly limited, but is usually about 0.1 to 10 mass%, preferably about 0.5 to 5 mass%, based on the total amount of the composition.

The lubricating oil composition may further contain an antioxidant. Examples of the antioxidant include amine-based antioxidants, phenol-based antioxidants, sulfur-based antioxidants, phosphorus-based antioxidants, molybdenum amine complex-based antioxidants, and among these, amine-based antioxidants and phenol- Do. Any of these known antioxidants used as antioxidants in conventional lubricating oils can be appropriately selected and used.

Examples of the amine-based antioxidant include diphenylamine-based ones such as diphenylamine and dialkyldiphenylamine having an alkyl group having 3 to 20 carbon atoms; naphthylamine and? -naphthylamine, and alkyl-substituted phenyl-? -naphthylamine having 3 to 20 carbon atoms.

Examples of the phenolic antioxidant include 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, octadecyl- 5-di-tert-butyl-4-hydroxyphenyl) propionate; Diphenol type ones such as 4,4'-methylenebis (2,6-di-tert-butylphenol) and 2,2'-methylenebis (4-ethyl- have.

And thauryl-3,3'-thiodipropionate as a sulfur-based antioxidant, and phosphite as a phosphorus-based antioxidant.

Examples of the molybdenum amine complex antioxidant include those obtained by reacting a hexavalent molybdenum compound, specifically, molybdenum trioxide and / or molybdenum acid with an amine compound, for example, Japanese Patent Application Laid-Open No. 2003-252887 A compound obtained by the production method described in the publication can be used.

These antioxidants may be used alone or in combination of two or more thereof in any combination, but it is generally preferable to use a combination of two or more.

The content of the antioxidant is preferably about 0.01 to 10 mass%, more preferably about 0.1 to 5 mass%, based on the total amount of the composition.

The lubricating oil composition may further contain at least one additive selected from friction modifiers and wear resistance agents other than the above.

Specific examples thereof include sulfur compounds such as sulfide olefin, dialkyl polysulfide, diaryl alkyl polysulfide and diaryl polysulfide, phosphoric acid esters, thio phosphoric acid esters, phosphorous acid esters, alkylhydrogen phosphites, phosphoric acid ester amines (ZnDTC), oxymolybdenum sulfanedionganophosphorodithioate (MoDTP), oxymolybdenum dithiocarbamate (MoDTC) sulfide, phosphorus compounds such as phosphorus acid salt, phosphorus acid ester amine salt, And non-cyclic friction modifiers such as organic metal compounds, amine compounds, fatty acid esters, fatty acid amides, fatty acids, aliphatic alcohols, aliphatic ethers, urea compounds, hydrazide compounds and the like. These may be used singly or in combination of two or more.

Among them, it is preferable to use oxymolybdenum dithiocarbamate sulfide from the viewpoint of fuel economy saving. The content of the friction modifier and the wear resistance agent is preferably about 0.01 to 8 mass%, more preferably 0.1 to 5 mass%, based on the whole composition.

The lubricating oil composition may further contain components such as a pour point depressant, a metal deactivator, a pour point depressant, and a defoaming agent.

The kinetic viscosity at 100 캜 of the lubricating oil composition of the present invention is not particularly limited, but is usually about ^{2 to} 25 mm ² / s, preferably 3 to 22 mm ² / s, more preferably 4 to 17 mm ² / s. By making the composition have such a low viscosity, it becomes easy to improve fuel economy. The viscosity index of the lubricating oil composition is preferably 150 or more, more preferably about 170 to 300, and even more preferably about 180 to 250.

The lubricating oil composition of the present invention is a lubricating oil composition for an internal combustion engine used for various internal combustion engines such as four-wheeled automobiles and two-wheeled automobiles. When performing a city driving operation in which a car is repeatedly used in a car, for example, with a turbo mechanism equipped engine capable of achieving high output, caulking and copper leaching tend to occur in a lubricating oil composition used in an internal combustion engine. However, And copper elution can be suppressed in a balanced manner.

[Production method of lubricating oil composition]

The method for producing a lubricating oil composition of the present invention comprises (A) blending the components (B) and (C) in a lubricating base oil to prepare a lubricating oil composition. In the method for producing a lubricating oil composition of the present invention, the above components (D) and (E) and other components may be added to the lubricating base oil in addition to the components (B) and (C).

The amount of the lubricating oil (A) and the amount (blending amount) of the components (B) to (E) and the other components are the same as those of the respective components described above. The details are the same as described above, so the description thereof will be omitted.

In the present production method, each component may be blended in a base oil by any method, and the technique is not limited.

On the other hand, the lubricating oil composition comprising the components (B) and (C), and further optionally, one or more components selected from the components (D) and (E) . In some cases, however, at least a part of the compounded additives may be formed into other compounds by reaction or the like.

Example

Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples at all.

In the present specification, the measurement of each physical property and the evaluation of the lubricating oil composition are obtained in accordance with the following description.

(1) Kinematic viscosity

This value is measured by using a glass tube type clay system according to JIS K2283.

(2) Viscosity Index

Measured according to JIS K2283.

(3) NOACK evaporation amount

It is a value measured according to the method specified in JPI-5S-41.

(4) Paraffin content (% C _P )

(%) Of the paraffin components calculated by the ring analysis n-d-M method, as measured according to ASTM D-3238.

(5)

Measured by the perchloric acid method in accordance with JIS K2501.

(6) Average carbon number of poly (meth) acrylate (X)

^It was calculated from chemical shifts and integral values of < ¹³ > C-NMR. Specifically, first, the ratio of each alkyl group was calculated from the sum of the integral values of the alkyl groups and the integral value of each alkyl group, and was calculated by the following formula.

The average number of carbon atoms X = (the number of carbon atoms of each alkyl group x the ratio of each alkyl group)

The measurement conditions of < ¹³ > C-NMR are as follows.

Apparatus: ECX-400P (manufactured by JEOL) Solvent: CDCl3

Resonance frequency: 100MHz Measuring Mode: Decoupling with Gate

Ring method

Accumulated count: 2000 ~ 5000 Pulse delay time: 25 s

Pulse width: 9.25us x-angle: 90 °

(7) Weight average molecular weight (Mw) of poly (meth)

The weight average molecular weight (Mw) is measured under the following conditions and is a value obtained by using polystyrene as a calibration curve. Specifically, it is measured under the following conditions.

Apparatus: Agilent 1260 HPLC Column: ShodexLF404 × 2

Solvent: chloroform Temperature: 35 ℃

Sample concentration: 0.05% Calibration curve: polystyrene

Detector: Differential refraction detector

(8) reduction rate of infectious agent and base after deterioration by ISOT

At the ISOT test (165.5 占 폚) in accordance with JIS K2514, a copper piece and a steel piece as a catalyst were put into a test oil (lubricating oil composition), the test oil was forcibly deteriorated, and a permeating agent (perchloric acid method) after 96 hours was measured. In addition, the rate of reduction of the test strain by the deterioration of the infectious agent of new strain was calculated. The lower the reduction rate, the higher the retention of the base and the longer-drain usable long-drain.

(9) Amount of copper eluted after deterioration by ISOT

The elution amount of copper in the test oil after the deterioration by the ISOT test was measured.

(10) Panel caulking test

Under the conditions of the panel temperature of 300 占 폚 and the oil temperature of 100 占 폚 according to the Federal test method 791B 占 3462, the test was carried out for 3 hours in a cycle of a splash time of 15 seconds and a stop time of 45 seconds. After completion of the test, the caulking material adhered to the panel was evaluated.

[Examples 1 to 9, Comparative Examples 1 to 4]

As shown in Table 1, components (B) to (E) and other components were blended with (A) a lubricating base oil, and (A) a lubricating base oil and lubricating oil compositions of Examples and Comparative Examples containing these components And the lubricating oil composition was evaluated. The results are shown in Table 1.

* Each component in Table 1 indicates the following.

(A) Lubricant base oil

The lubricant base oil (A1): GroupIII 150N hydrogenated refined base oil, kinematic viscosity 100 ℃ 6.4mm ² / s, viscosity index 131, NOACK evaporation amount (250 ℃, 1 hour) 7.0% by mass, ndM ring analysis% C _P. 79.1%

The lubricant base oil (A2): GroupIII 100N hydrogenated refined base oil, 12.9% by weight 100 Kinematic viscosity ℃ 4.1mm ² / s, viscosity index 134, NOACK evaporation amount (250 ℃, 1 sigan), ndM ring analysis% C _P. 87.7%

Lubricant base oil (A3): Group IV polyalphaolefin, 100 占 폚 kinematic viscosity 3.7 mm ² / s, viscosity index 117, NOACK evaporation amount (250 占 폚, 1 hour) 15.6 mass%

Lubricant base oil (A4): Group IV ester base oil, 100 캜 Kinematic viscosity 4.3 mm ² / s, viscosity index 139, NOACK evaporation amount (250 캜, 1 hour) 2.6 mass%

(On the other hand, in the eighth embodiment, the lubricating oil base oil is a mixture of lubricating oil base oil will (A3) and the lubricating oil base oil (A4), the kinematic viscosity of the mixed base oil 100 ℃ 4.3mm ² / s, viscosity index was 130.)

(B) boron-containing succinic acid imide

Boron-containing succinic acid imide (B1): boronate of polybutene monobasic acid imide, boron content 1.3 mass%, nitrogen content 1.2 mass%, weight average molecular weight of polybutene diol 1,800, B / N ratio 1.1

(C) a poly (meth) acrylate

Average molecular weight: 200,000, average number of carbon atoms (X): 4.6, resin content: 28% by mass, poly (meth) acrylate

Average molecular weight of 510,000, an average carbon number (X) of 5.7, and a resin content of 19 mass% or less. The poly (meth) acrylate (C2)

(Meth) acrylate (C3): polyalkyl (meth) acrylate, weight average molecular weight 440,000, average carbon number (X): 5.8, resin content: 16 mass%

Average molecular weight of 370,000, an average carbon number (X) of 5.6, a resin content of 26% by mass, a poly (meth) acrylate (C4)

(Meth) acrylate (C5): polyalkyl (meth) acrylate, weight average molecular weight 430,000, average carbon number (X): 6.3, resin content: 42 mass%

Average molecular weight: 44,000, average number of carbon atoms (X): 7.3, resin content: 53% by mass, poly (meth) acrylate (C6)

(Meth) acrylate (C7): polyalkyl (meth) acrylate, weight average molecular weight 90,000, average carbon number (X): 8.1, resin content: 46 mass%

(Meth) acrylate (C8): polyalkyl (meth) acrylate, weight average molecular weight 210,000, average carbon number (X): 9.4, resin content: 44 mass%

(D) Zinc dithiophosphate

ZnDTP (D1): zinc dialkyldithiophosphate, zinc content 9.0 mass%, phosphorus content 8.2 mass%, sulfur content 17.1 mass%, alkyl group; A mixture of a secondary butyl group and a secondary hexyl group

(E) Metal cleaner

(Perchloric acid method) 255 mg KOH / g, calcium content 9.3% by mass, sulfur content 3.0% by mass < tb >

(E2): basic calcium salicylate, a transferring agent (perchloric acid method) 225 mgKOH / g, a calcium content of 7.8 mass%, a sulfur content of 0.2 mass%

Metal cleaner (E3): basic calcium sulfonate, transferring agent (perchloric acid method) 300 mg KOH / g, calcium content 11.6% by mass, sulfur content 1.49%

· Other ingredients

Boron-free succinic acid imide: polybutene monobasic acid bisimide, number average molecular weight of polybutene diol of 2300, nitrogen content of 1.0% by mass, chlorine content of 0.01% by mass or less

Amine antioxidant: dialkyldiphenylamine, nitrogen content 4.62 mass%

Phenol antioxidant: octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate

MoDTC: oxymolybdenum sulfide dithiocarbamate, molybdenum content 10.0 mass%, sulfur content 11.5 mass%

As apparent from the results of Table 1, the lubricating oil compositions of Examples 1 to 9 contain boron-containing succinic acid imides and polyalkyl (meth) acrylates having specific Mw and Mw / X, It was possible to suppress occurrence of caulking and copper elution while suppressing the decrease of the base content in the product.

On the other hand, in Comparative Examples 1 to 3, occurrence of caulking and copper elution could not be sufficiently suppressed because Mw or Mw / X of polyalkyl (meth) acrylate was not within a predetermined range. Further, since the lubricating oil composition of Comparative Example 4 contains no boron-containing succinic acid imide, even if the Mw or the Mw / X of the polyalkyl (meth) acrylate falls within a predetermined range, the occurrence of caulking and copper elution It could not be suppressed.

INDUSTRIAL APPLICABILITY The lubricating oil composition for an internal combustion engine of the present invention can balance the generation of base deterioration, occurrence of caulking and copper elution, and can be suitably used, for example, in an internal combustion engine for an automobile.

Claims (9)

(A) a lubricating oil base oil made of mineral oil and / or synthetic oil,
(B) a boron-containing alkenylsuccinic acid imide and / or a boron-containing alkylsuccinic acid imide in an amount of 0.001 to 0.1% by mass in terms of a boron content based on the total amount of the composition,
Wherein Mw is 100,000 to 700,000, Mw / X is 30,000 or more, and 0.1 to 30% by mass, based on the total amount of the composition, based on the weight average molecular weight is Mw and the average carbon number of the alkyl group measured by ¹³ C- (C) a lubricating oil composition for an internal combustion engine containing poly (meth) acrylate. The method according to claim 1,
A lubricating oil composition for an internal combustion engine having Mw / X of 30,000 to 200,000. 3. The method according to claim 1 or 2,
(C) a lubricating oil composition for an internal combustion engine in which poly (meth) acrylate is non-dispersed. 4. The method according to any one of claims 1 to 3,
(A) A lubricating oil composition for an internal combustion engine having a viscosity index of a lubricating oil base oil of 90 or more. 5. The method according to any one of claims 1 to 4,
Wherein the mineral oil has a paraffin content (% C _P ) of at least 60% by ring analysis. 6. The method according to any one of claims 1 to 5,
(D) zinc dithiophosphate, and (E) an alkali metal-based detergent or an alkaline earth metal-based detergent. The method according to claim 6,
(D) 0.01 to 0.15 mass% of (D) zinc dithiophosphate in terms of trace, (E) 0.1 to 0.3 mass% of an alkali metal detergent or an alkaline earth metal detergent in terms of metal amount Lubricant composition. 8. The method according to any one of claims 1 to 7,
And a kinematic viscosity at 100 占 폚 of 4 to 17 mm ² / s. (B) a boron-containing alkenylsuccinic acid imide and / or a boron-containing alkylsuccinic acid imide in an amount of 0.001 to 0.1% by mass in terms of the total amount of the composition based on the total amount of the composition, (C) a poly (meth) acrylate in an amount of 0.1 to 30 mass% based on the total amount of the composition to prepare a lubricating oil composition for an internal combustion engine,
(C) a poly (meth) acrylate having an Mw of 100,000 to 700,000 and an Mw / X of 30,000 or more, wherein the weight average molecular weight is Mw and the average carbon number of the alkyl group measured by ¹³ C- A method for producing a lubricating oil composition for engines.