JP4597223B2 - Lubricating oil composition for internal combustion engines - Google Patents

Abstract

A lubricating oil composition for internal combustion engines contains: base oil; (A) a boronated product of a polyalkenyl succinimide compound; (B) molybdenum dithiocarbamate; and (C) zinc dialkyldithiophosphate. The component (A) is a boronated product of a succinimide compound represented by the following formula (1), and the succinimide compound is obtained by reacting (a) a succinic acid or its anhydride substituted by a polyalkenyl group with (b) polyalkylene polyamine of which 5 mol% or more of the entirety has a ring structure at its terminal. B/N ratio thereof is 0.5 or more, and a content of the component (A) is 0.01 to 0.1 mass% of the total amount of the composition in terms of boron. The component (B) is MoDTC represented by the following formula (2), and a content of the component (B) is 0.01 to 0.08 mass% of the total amount of the composition in terms of Mo. A content of the component (C) is 0.01 to 0.09 mass% of the total amount of the composition in terms of phosphorus. Each symbol in the above formulae means the same as described in the description.

Description

The present invention relates to a lubricating oil composition for internal combustion engines used in diesel engines, gasoline engines, and the like.

Currently, environmental regulations on a global scale are becoming stricter, and the situation surrounding automobiles is becoming stricter, such as fuel efficiency regulations and exhaust gas regulations. This is due to environmental issues such as global warming and resource protection from concerns over the depletion of petroleum resources. For these reasons, it is considered that the fuel saving of automobiles will be promoted more and more.
In diesel engines, measures for reducing environmental pollution caused by exhaust gas components such as particulate matter (PM) and NOx are important issues. As a countermeasure, it is effective to mount an exhaust gas purification device such as a particulate filter or an exhaust gas purification catalyst (oxidation or reduction catalyst) on the automobile. On the other hand, when a conventional lubricating oil for an internal combustion engine is used in an automobile equipped with such an exhaust gas purification device, the soot adhering to the particulate filter is removed by oxidation and combustion, but the metal oxide generated by combustion In addition, there is a problem that the filter is clogged by phosphate, sulfate, carboxylate, or the like. A part of the used engine oil is burned and discharged as exhaust gas. Therefore, it is preferable that the metal content and sulfur content in the lubricating oil be as small as possible. Furthermore, in order to prevent the catalyst from deteriorating, it is also necessary to reduce the phosphorus content and sulfur content in the lubricating oil.
Under such circumstances, ash clogging in the diesel particulate filter (DPF) can be reduced, the flammability of PM collected by the DPF can be improved, and PM can be stably burned at low temperatures. A lubricating oil composition for DPF-equipped diesel engines has been developed that can increase the removal efficiency and extend the life of the DPF. For example, lubrication for diesel engines with a diesel particulate removal device characterized in that the sulfated ash content is 1.0% by weight or less, the sulfur content is 0.3% by weight or less, and the molybdenum content is 100 ppm or more. An oil composition is disclosed (for example, see Patent Document 1).

In addition, in order to reduce the fuel consumption of automobiles, it is possible to reduce the viscosity of the engine oil to prevent friction loss in the engine as well as to improve the automobile itself, such as reducing the weight of the automobile and improving the engine. Improvement of engine oil, such as addition, is also important.
On the other hand, lowering the viscosity of engine oil also causes an increase in wear at various parts of the engine. Therefore, friction modifiers, extreme pressure agents, and the like are added for the purpose of reducing friction loss accompanying wear reduction of engine oil and preventing wear, and phosphorus-containing compounds are generally used as extreme pressure agents. However, it is known that the phosphorus-containing compound deteriorates the catalyst that purifies the exhaust gas as described above, and it is desirable to reduce the phosphorus-containing compound in the engine oil as much as possible. However, in that case, it may be difficult to maintain the wear prevention performance of the engine over a long period of time, so a method for maintaining the wear prevention performance is required.
As one countermeasure, a friction modifier containing molybdenum or an amine or ester ashless friction modifier is often added. However, these additives have a large friction reducing effect, but depending on the additive and amount added, the consumption rate may increase due to oxidative degradation, and it may not be expected to maintain the performance of engine oil for a long period of time. There is sex.
In order to solve such a problem, an engine oil composition in which a mineral oil or a synthetic oil is blended with an alkenyl succinimide boron compound derivative, an organomolybdenum compound, a specific alkylated thiadiazole and a specific fatty acid ester has been proposed (for example, Patent Document 2). In addition, engine oil compositions in which an alkaline earth metal chlorosulfurized mixture of hydroxybenzoic acid and alkylphenol is blended at a specific ratio instead of the specific alkylated thiadiazole or the specific fatty acid ester have been proposed (for example, patents). Reference 3).

  Apart from this, it has been proposed to use a succinimide having a specific structure as an ashless dispersant instead of or in combination with a metallic detergent (for example, a patent) References 4 and 5). This type of ashless dispersant disperses finely the diesel suit that is produced during combustion and sludge generated by oxidative degradation of engine oil, preventing them from adhering to engine parts, and improving the cleanliness of the piston. There is an effect to improve.

JP 2002-060776 A JP-A-11-269476 JP-A-11-269477 Japanese Patent Laid-Open No. 2001-226381 JP 2001-247623 A

However, in conventional lubricating oils as described in Patent Documents 1 to 5, the friction reducing ability that can be satisfied in practice is maintained over a long period of time while maintaining the content of the metal component and the phosphorus component at a low level. It is difficult to do. Furthermore, in such a conventional lubricating oil, the present situation is that a sufficient friction reducing effect has not yet been achieved under the mixture of diesel suits.
Therefore, the present invention is used in internal combustion engines such as gasoline engines, diesel engines, and gas engines under such circumstances, and even when the content of metal components and phosphorus components is maintained at a low level, An object of the present invention is to provide a lubricating oil composition for an internal combustion engine that can exhibit a high friction reducing effect for a long period of time and can maintain this effect even if a diesel suit is mixed in a diesel engine.

In order to solve the above problems, the present invention provides the following lubricating oil composition for an internal combustion engine.
[1] For an internal combustion engine comprising a base oil composed of mineral oil and / or synthetic oil, (A) a boride of a polyalkenyl succinimide compound, (B) molybdenum dithiocarbamate, and (C) zinc dialkyldithiophosphate A lubricating oil composition, wherein the component (A) is (a) succinic acid substituted with a polyalkenyl group having a number average molecular weight of 500 to 5,000 or an anhydride thereof, and (b) 5 mol% of the total. The above is a boride of a polyalkenyl succinimide compound represented by the following formula (1) obtained by reacting with a polyalkylene polyamine having a piperazinyl group at the terminal, and a mass ratio of boron and nitrogen (B / N ratio) ) Is 0.5 or more, and the content of the component (A) is 0.01 to 0.1% by mass in terms of boron based on the total amount of the composition,

（式中、Ｒ^１は数平均分子量５００〜５，０００のポリアルケニル基、Ｒ^２、Ｒ^３、Ｒ
^４およびＲ^５はそれぞれ独立に水素または炭素数１〜３のアルキル基、ｑは２〜４の整数、ｎは０〜３の整数、ｒは２〜４の整数を示し、Ａはアミノ基またはピペラジニル基である。）
前記（Ｂ）成分が下記式（２）で示されるモリブデンジチオカーバメート（ＭｏＤＴＣ）であって、該（Ｂ）成分の含有量が組成物全量基準においてモリブデン量換算で０．０１〜０．０８質量％であり、

(In the formula, R ¹ is a polyalkenyl group having a number average molecular weight of 500 to 5,000, R ² , R ³ , R
⁴ and R ⁵ are each independently hydrogen or an alkyl group having 1 to 3 carbon atoms, q is an integer of 2 to 4, n is an integer of 0 to 3, r is an integer of 2 to 4, and A is an amino group or Piperazinyl group. )
The component (B) is molybdenum dithiocarbamate (MoDTC) represented by the following formula (2), and the content of the component (B) is 0.01 to 0.08 mass in terms of molybdenum based on the total amount of the composition. %

（式中、Ｒ⁶〜Ｒ⁹はそれぞれ独立に炭素数４〜２２のヒドロカルビル基を表し、Ｘ^１〜Ｘ⁴は、各々硫黄原子または酸素原子を表す。）
前記（Ｃ）成分の含有量が組成物全量基準においてリン量換算で０．０１〜０．０９質量％であることを特徴とする内燃機関用潤滑油組成物。

(In the formula, R ^{6 to} R ⁹ each independently represents a hydrocarbyl group having ⁴ to 22 carbon atoms, and X ^{1 to} X ⁴ each represents a sulfur atom or an oxygen atom.)
The internal combustion engine lubricating oil composition, wherein the content of the component (C) is 0.01 to 0.09% by mass in terms of phosphorus on the basis of the total amount of the composition.

[2] In the lubricating oil composition for an internal combustion engine according to [1], the sulfur content is 0.3% by mass or less based on the total amount of the composition, and the sulfated ash content is 0.8% based on the total amount of the composition. % Lubricating oil composition for internal combustion engines.

  According to the lubricating oil composition for an internal combustion engine of the present invention, since it contains a boride of a polyalkenyl succinimide compound having a specific structure and molybdenum dithiocarbamate, the content of the metal component or phosphorus component is lowered to a low level. While maintaining, it is excellent in the friction reduction effect as a new oil, and can further exhibit a high friction reduction effect in the new oil for a long period of time, and this effect can be maintained even if a diesel suit is mixed. That is, it has a low ash content and low phosphorus, and can be suitably used for an internal combustion engine such as a gasoline engine, a diesel engine, and a gas engine as a lubricating oil composition for an internal combustion engine that meets environmental regulations.

  The lubricating oil composition for internal combustion engines of the present invention (hereinafter also simply referred to as “the present composition”) comprises a base oil, (A) a boride of a succinimide compound, (B) molybdenum dithiocarbamate (hereinafter, And (C) zinc alkyldithiophosphate (hereinafter also referred to as “ZnDTP”). Hereinafter, these base oils and each additive component will be described in detail.

[Base oil]
Mineral oil and / or synthetic oil is used as the base oil of the composition. There is no restriction | limiting in particular about the kind of this mineral oil or synthetic oil, Arbitrary things can be suitably selected and used from the mineral oil and synthetic oil conventionally used as a base oil of the lubricating oil for internal combustion engines.
As mineral oil, for example, a lubricating oil fraction obtained by distillation under reduced pressure of atmospheric residual oil obtained by atmospheric distillation of crude oil can be desolvated, solvent extracted, hydrocracked, solvent dewaxed, catalytic dehydrated. Mineral oil refined by one or more treatments such as wax, hydrorefining, or the like, or mineral oil produced by isomerizing wax, GTL WAX, and the like.
Synthetic oils include, for example, polybutene, polyolefins [α-olefin homopolymers and copolymers (for example, ethylene-α-olefin copolymers)], various esters (for example, polyol esters and dibasic acid esters). And phosphoric acid esters), various ethers (for example, polyphenyl ether), polyglycol, alkylbenzene, alkylnaphthalene, and the like. Of these synthetic oils, polyolefins and polyol esters are particularly preferable from the viewpoints of viscosity characteristics, solubility of additives, and compatibility with seal rubbers.
In this invention, 1 type of the said mineral oil may be used as a base oil, and may be used in combination of 2 or more type. Moreover, the said synthetic oil may be used 1 type and may be used in combination of 2 or more type. Further, one or more mineral oils and one or more synthetic oils may be used in combination.
Although there is no restriction | limiting in particular about the viscosity of a base oil, Although it changes according to the use of a lubricating oil composition, it is preferable that the kinematic viscosity of 100 degreeC is 2-30 mm < ² > / s, More preferably, it is 3-15 mm < ² > / s. Even more preferably, it is 4 to 10 mm ² / s. If the kinematic viscosity at 100 ° C. is 2 mm ² / s or more, the evaporation loss is small. On the other hand, if it is 30 mm ² / s or less, the power loss due to the viscous resistance does not increase so much and the fuel efficiency improvement effect is obtained.

Further, as the base oil, those having a% CA of 3.0 or less by ring analysis and a sulfur content of 50 mass ppm or less are preferably used. Here,% CA by ring analysis indicates a ratio (percentage) of an aromatic component calculated by a ring analysis ndM method. Further, the sulfur content is a value measured according to JIS K2541.
A base oil having a% CA of 3.0 or less and a sulfur content of 50 mass ppm or less has good oxidation stability, can suppress an increase in acid value and generation of sludge, and is corrosive to metals. Less lubricating oil composition can be provided.
More preferable% CA is 1.0 or less, and further 0.5 or less, and a more preferable sulfur content is 30 ppm by mass or less.
Furthermore, the viscosity index of the base oil is preferably 70 or more, more preferably 100 or more, and still more preferably 120 or more. The base oil having a viscosity index of 120 or more has a small change in viscosity due to a change in temperature.

[Component (A)]
The component (A) used in the present invention is composed of (a) succinic acid substituted with a polyalkenyl group having a number average molecular weight of 500 to 5,000 or an anhydride thereof, and (b) 5 mol% or more of the whole ring is terminated. It is a boride of a polyalkenyl succinimide compound represented by the following formula (1) obtained by reacting with a polyalkylene polyamine having a structure.

（式中、Ｒ^１は数平均分子量５００〜５，０００のポリアルケニル基、Ｒ^２、Ｒ^３、Ｒ^４およびＲ^５はそれぞれ独立に水素または炭素数１〜３のアルキル基、ｑは２〜４の整数、ｎは０〜３の整数、ｒは２〜４の整数を示し、Ａはアミノ基またはポリアルキレンポリアミンの末端と同じ環構造の基である。）

Wherein R ¹ is a polyalkenyl group having a number average molecular weight of 500 to 5,000, R ² , R ³ , R ⁴ and R ⁵ are each independently hydrogen or an alkyl group having 1 to 3 carbon atoms, and q is 2 to 2 4 is an integer, n is an integer of 0 to 3, r is an integer of 2 to 4, and A is a group having the same ring structure as the end of the amino group or polyalkylene polyamine.

When the number average molecular weight of the polyalkenyl group in the component (a) is less than 500, the borated product of the succinimide compound of the formula (1) may not be sufficiently dissolved in the lubricating base oil. On the other hand, when the number average molecular weight of the polyalkenyl group exceeds 5,000, the polyalkenyl succinimide compound becomes highly viscous and it may be difficult to handle. Therefore, the number average molecular weight of the polyalkenyl group is preferably 500 to 5,000, more preferably 800 to 3,000.
As the polyalkenyl group having such a molecular weight, a polymer or copolymer of a monoolefin or diolefin having 2 to 16 carbon atoms is usually used. Specific examples of the monoolefin include ethylene, propylene, butene, butadiene, decene, dodecene, hexadecene and the like. Among these monoolefins, in the present invention, butene is particularly preferable from the viewpoint of improving the cleanliness of engine parts at high temperatures and being easily available, and a polybutenyl group that is a polymer thereof is preferable.
The succinic acid substituted with a polyalkenyl group or its anhydride may be reacted with polybutene corresponding to the molecular weight of the polyalkenyl group and maleic anhydride by a known method.

The polyalkylene polyamine as the component (b) may be a polyalkylene polyamine having a ring structure at the terminal, the polyalkylene polyamine having a ring structure at the terminal, and a polyalkylene polyamine having no ring structure at the terminal. It may be a mixture of However, if the proportion of the polyalkylene polyamine having a ring structure at the terminal is less than 5 mol%, the high-temperature cleanliness and oxidation stability become insufficient, and this proportion may be 10 mol% or more, further 20 mol% or more. In this case, the high-temperature cleanliness and oxidation stability are further improved. Further, the upper limit of the ratio of the polyalkylene polyamine having a ring structure at the terminal is preferably 95 mol% or less, and more preferably 90 mol% or less. If this ratio exceeds 95 mol%, the produced boronated succinimide compound may have a high viscosity, which may reduce the production efficiency of this compound, and the dissolution of this product in the lubricating base oil This is because the properties may deteriorate. Therefore, the proportion of the polyalkylene polyamine having a ring structure at the terminal is more preferably from 5 to 95 mol%, further preferably from 10 to 90 mol%.
Further, the terminal ring structure of the polyalkylene polyamine having a ring structure at the terminal is preferably represented by the following formula (1 ′).

  Here, in the above formula (1 ′), p1 and p2 represent integers of 2 to 4. Among these, those in which both p1 and p2 are 2, that is, piperazinyl group are particularly preferable. Typical examples of polyalkylene polyamines having a ring structure at the end include, for example, aminoethylpiperazine, aminopropylpiperazine, aminobutylpiperazine, amino (diethylenediamino) piperazine, amino (dipropyldiamino) piperazine and the like having a piperazinyl structure at the end. An aminoalkyl piperazine is mentioned. Among these, aminoethylpiperazine is particularly preferable because it is easily available.

On the other hand, examples of the polyalkylene polyamine having no ring structure at the terminal include an acyclic polyalkylene polyamine having no ring structure and a polyalkylene polyamine having a ring structure other than the terminal.
Typical examples of polycyclic polyamines having an acyclic structure include polyethylene polyamines such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, propylenediamine, dibutylenetriamine, and butylenetriamine. Can be mentioned. Further, representative examples of the polyalkylene polyamine having a ring structure other than the terminal include di (aminoalkyl) piperazine such as di (aminoethyl) piperazine.

  Among these polyalkylene polyamines that may contain a ring structure, mixtures with polyethylene polyamines such as triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine are particularly advantageous in that they are easy to obtain due to their high-temperature cleanability. preferable.

  The component (A) in the present invention is a boride of a polyalkenyl succinimide compound obtained from the components (a) and (b) described above. This boride can be obtained by reacting a polyalkenyl succinimide compound obtained from the component (a) and the component (b) with a boron compound as the component (c). Examples of the boron compound include boric acid, boric anhydride, boric acid ester, boron oxide, and boron halide. Of these, boric acid is particularly preferable.

This reaction method is not particularly limited and may be carried out by a known method. For example, the target product can be obtained by the following reaction. First, the component (a) is reacted with the component (b), and then the reaction product is reacted with the component (c). About the mixture ratio of (a) and (b) in reaction of (a) component and (b) component, (a) :( b) is preferable 0.1-10: 1 (molar ratio), 0.5 -2: 1 (molar ratio) is more preferable. Moreover, about reaction temperature of (a) component and (b) component, about 80-250 degreeC is preferable, and about 100-200 degreeC is more preferable. In carrying out the reaction, a solvent, for example, an organic solvent such as a hydrocarbon oil can be used as needed for handling the raw materials or adjusting the reaction.
Next, the reaction product of the component (a) and the component (b) obtained as described above is reacted with the component (c). The compounding ratio of the boron compound as the component (c) is usually preferably 1: 0.05 to 10 and more preferably 1: 0.5 to 5 in terms of a molar ratio with respect to the polyalkylene polyamine. Moreover, about reaction temperature, Preferably it is about 50-250 degreeC, More preferably, it is 100-200 degreeC.
Also, when the reaction is performed, the reaction product is used as a solvent, for example, an organic solvent such as hydrocarbon oil, in order to adjust the reaction and the reaction, as in the reactions of the raw materials (a) and (b). You can also.

By the reaction described above, a borate of a succinimide compound substituted with a polyalkenyl group having a number average molecular weight of 200 to 5000 as component (A) is obtained as a product. In this invention, (A) component may be used individually by 1 type, and may be used in combination of 2 or more type.
As the component (A), as described above, it is a borated product of a polyalkenyl succinimide compound having the structure of the formula (1), and a polyalkenyl succinimide compound containing no boron is further used in combination. Also good. In addition, the polyalkenyl succinimide compound used at that time may be a monoimide type or a bisimide type, but the alkenyl group has a number average molecular weight of 1500 from the viewpoint of low corrosion resistance to a metal material, compatibility with a seal rubber and improvement in oxidation stability. Polybutenyl succinic bisimide, which is ˜3000 polybutene, is particularly preferred.

The content of the component (A) in the composition is preferably 0.01 to 0.1% by mass, more preferably 0.01 to 0.1% by mass in terms of boron (atom) based on the total amount of the composition. It is 0.05 mass%, More preferably, it is 0.01-0.03 mass%. When a certain amount or more of boron contained in the component (A) is present, high piston cleanliness can be obtained in a high-temperature internal combustion engine. When the boron content is less than 0.01% by mass, sufficient high-temperature cleanability cannot be obtained. Further, even if the boron content exceeds 0.1% by mass, the high temperature cleanability cannot be further improved and the practicality is poor.
Further, the mass ratio (B / N) of boron (B) and nitrogen (N) in the component (A) is preferably 0.5 or more, more preferably 0.6 or more, and still more preferably 0.8. That's it. When B / N is 0.5 or more, the cleanliness of engine parts at high temperatures is greatly improved.
In addition, the boride of the boronated succinimide compound can be obtained by reacting the raw materials (a) and (b) as described above, and then reacting the reaction product with the raw material (c). By changing the reaction sequence, the raw materials (a) and (c) are first reacted, and then the reaction product and (b) are reacted to obtain the desired polyalkenyl succinimide compound borate. It is done.

[(B) component]
(B) component which comprises this composition is molybdenum dithiocarbamate (MoDTC) shown by following formula (2).

（式中、Ｒ⁶〜Ｒ⁹はそれぞれ独立に炭素数４〜２２のヒドロカルビル基を表し、Ｘ^１〜Ｘ⁴は、各々硫黄原子または酸素原子を表す。）

(In the formula, R ^{6 to} R ⁹ each independently represents a hydrocarbyl group having ⁴ to 22 carbon atoms, and X ^{1 to} X ⁴ each represents a sulfur atom or an oxygen atom.)

Here, in the above formula (2), R ^{6 to} R ⁹ are preferably hydrocarbon groups having 4 to 22 carbon atoms, such as an alkyl group, an alkenyl group, an alkylaryl group, a cycloalkyl group, and a cycloalkenyl group. Etc. Among these, R ^{6 to} R ⁹ are preferably a branched or straight chain alkyl group or alkenyl group having 4 to 18 carbon atoms, and more preferably an alkyl group having 8 to 13 carbon atoms. For example, n-octyl group, 2-ethylhexyl group, isononyl group, n-decyl group, isodecyl group, dodecyl group, tridecyl group, isotridecyl group and the like can be mentioned. This is because if the number of carbons is too small, the oil solubility becomes poor, and if the number of carbons is too large, the melting point increases, handling becomes worse, and the activity decreases. R ^{6 to} R ⁹ may be the same or different from each other, but when R ⁶ and R ⁷ and R ⁸ and R ⁹ are different alkyl groups, they are dissolved in the base oil. , Storage stability and durability of friction reduction ability are improved.
In the above formula (2), X ^{1 to} X ⁴ may each be a sulfur atom or an oxygen atom, and all of X ^{1 to} X ⁴ may be a sulfur atom or an oxygen atom. Here, the ratio of sulfur atom to oxygen atom is sulfur atom / oxygen atom = 1/3 to 3/1, and more preferably 1.5 / 2.5 to 3/1, in terms of corrosion resistance, It is preferable for improving the solubility in the base oil.

In this invention, the said (B) component may be used individually by 1 type, and may be used in combination of 2 or more type.
In addition, the content of the component (B) in the lubricating oil composition is 0.01 to 0.08% by mass, preferably 0.03 to 0.08% by mass in terms of molybdenum based on the total composition. To be prepared. If it is less than 0.01% by mass, a sufficient friction reducing effect cannot be obtained, and if it exceeds 0.08% by mass, the solubility in base oil and the corrosion resistance are deteriorated.

[Component (C)]
The composition further contains zinc dialkyldithiophosphate (ZnDTP) as the component (C). As ZnDTP, the thing of the structure shown by following formula (3) can be mentioned, for example.

上記式（３）において、Ｒ^１０、Ｒ^１１、Ｒ^１２およびＲ^１３は炭素数３〜２２の第１級または第２級のアルキル基または炭素数３〜１８のアルキル基で置換されたアルキルアリール基から選ばれた置換基を表し、それらは互いに同一であってもよいし、異なっていてもよい。

In the above formula (3), R ¹⁰ , R ¹¹ , R ¹² and R ¹³ are alkylaryl substituted with a primary or secondary alkyl group having 3 to 22 carbon atoms or an alkyl group having 3 to 18 carbon atoms. Represents a substituent selected from a group, and they may be the same or different.

In the present invention, these ZnDTPs may be used singly or in combination of two or more, but in particular, those having a secondary alkyl group zinc dithiophosphate as a main component, This is preferable because it increases the wear resistance.
Specific examples of ZnDTP include zinc dipropyldithiophosphate, zinc dibutyldithiophosphate, zinc dipentyldithiophosphate, zinc dihexyldithiophosphate, zinc diisopentyldithiophosphate, zinc diethylhexyldithiophosphate, zinc dioctyldithiophosphate, dinonyldithiophosphate. Zinc, zinc didecyl dithiophosphate, zinc didodecyl dithiophosphate, zinc dipropylphenyl dithiophosphate, zinc dipentylphenyl dithiophosphate, zinc dipropylmethylphenyl dithiophosphate, zinc dinonylphenyl dithiophosphate, zinc didodecylphenyl dithiophosphate, di Examples include zinc dodecylphenyl dithiophosphate.

  In the lubricating oil composition of the present invention, the content of ZnDTP as the component (C) is preferably 0.01 to 0.09% by mass in terms of phosphorus on the basis of the total amount of the composition, and preferably 0.02 to 0.02. 08 mass% is more preferable. In this composition, if the amount of phosphorus is less than 0.01% by mass, the wear resistance is not sufficient, and the friction reducing effect by the MoDTC of the component (B) is not sufficiently exhibited. On the other hand, if the amount of phosphorus exceeds 0.09% by mass, poisoning of the exhaust gas to the purification catalyst becomes remarkable, which is not preferable.

In the present composition, it is preferable to further add a phenol-based antioxidant and / or an amine-based antioxidant.
Examples of the phenolic antioxidant include octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 4,4′-methylenebis (2,6-di-t-butylphenol); 4 4,4'-bis (2,6-di-t-butylphenol); 4,4'-bis (2-methyl-6-t-butylphenol); 2,2'-methylenebis (4-ethyl-6-t-) 2,2′-methylenebis (4-methyl-6-tert-butylphenol); 4,4′-butylidenebis (3-methyl-6-tert-butylphenol); 4,4′-isopropylidenebis (2, 6-di-t-butylphenol); 2,2′-methylenebis (4-methyl-6-nonylphenol); 2,2′-isobutylidenebis (4,6-dimethylphenol); 2'-methylenebis (4-methyl-6-cyclohexylphenol); 2,6-di-t-butyl-4-methylphenol; 2,6-di-t-butyl-4-ethylphenol; 2,4-dimethyl -6-tert-butylphenol; 2,6-di-tert-amyl-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-t-butylbenzyl) sulfide; bis (3,5-di-t-butyl-4-hydroxybenzyl) sulfide; n-octyl-3- (4-hydroxy-3, 5 Di-t-butylphenyl) propionate, n-octadecyl-3- (4-hydroxy-3,5-di-t-butylphenyl) propionate; 2,2′-thio [diethyl-bis-3- (3,5 -Di-t-butyl-4-hydroxyphenyl) propionate] and the like. Among these, bisphenol-based and ester group-containing phenol-based ones are particularly preferable.

  Examples of amine antioxidants include monooctyl diphenylamine; monoalkyl diphenylamines such as monononyl diphenylamine; 4,4′-dibutyldiphenylamine; 4,4′-dipentyldiphenylamine; 4,4′-dihexyldiphenylamine; 4,4′-diheptyldiphenylamine; 4,4′-dioctyldiphenylamine; dialkyldiphenylamines such as 4,4′-dinonyldiphenylamine; tetrabutyldiphenylamine; tetrahexyldiphenylamine; tetraoctyldiphenylamine; polyalkyldiphenylamine such as tetranonyldiphenylamine And naphthylamine-based, specifically α-naphthylamine; phenyl-α-naphthylamine; further butylphenyl-α Naphthylamine; pentylphenyl -α- naphthylamine; hexylphenyl -α- naphthylamine; heptylphenyl -α- naphthylamine; octylphenyl -α- naphthylamine; and alkyl-substituted phenyl -α- naphthylamine, such as nonylphenyl -α- naphthylamine. Among these, the diphenylamine type is more preferable than the naphthylamine type in terms of the antioxidant effect.

In the present invention, a molybdenum amine antioxidant may be further added as another antioxidant. As the molybdenum amine antioxidant, a hexavalent molybdenum compound, specifically, a product obtained by reacting molybdenum trioxide and / or molybdic acid with an amine compound, for example, the production described in JP-A No. 2003-252887 The compound obtained by the method can be used. Although it does not restrict | limit especially as an amine compound made to react with a hexavalent molybdenum compound, Specifically, a monoamine, diamine, a polyamine, and an alkanolamine are mentioned. More specifically, it has an alkyl group having 1 to 30 carbon atoms such as methylamine, ethylamine, dimethylamine, diethylamine, methylethylamine, and methylpropylamine (these alkyl groups may be linear or branched). Alkylamines; alkenylamines having 2 to 30 carbon atoms such as ethenylamine, propenylamine, butenylamine, octenylamine, and oleylamine (these alkenyl groups may be linear or branched); methanolamine, ethanolamine , Alkanolamines having 1 to 30 carbon atoms such as methanolethanolamine and methanolpropanolamine (these alkanol groups may be linear or branched); methylenediamine, ethylenediamine, propylene Amines and alkylenediamines having 1 to 30 carbon atoms such as butylenediamine; polyamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine; undecyldiethylamine, undecyldiethanolamine, dodecyldipropanolamine , Oleyldiethanolamine, oleylpropylenediamine, stearyltetraethylenepentamine and other monoamines, diamines, polyamines having a C8-20 alkyl group or alkenyl group, and heterocyclic compounds such as imidazoline; alkylene oxides of these compounds And adducts; and mixtures thereof. Moreover, the sulfur containing molybdenum complex etc. of the succinimide described in Japanese Patent Publication No. 3-22438 and Unexamined-Japanese-Patent No. 2004-2866 can be illustrated.
The content of the antioxidant described above is preferably 0.3% by mass or more, and more preferably 0.5% by mass or more, based on the total amount of the composition. On the other hand, if it exceeds 2% by mass, it may become insoluble in the lubricating base oil. Therefore, the blending amount of the antioxidant is preferably in the range of 0.3 to 2% by mass based on the total amount of the composition.

  The lubricating oil composition for an internal combustion engine of the present invention may further contain other additives such as a viscosity index improver, a metallic detergent, and an ashless friction reducing agent as necessary, as long as the effects of the present invention are not impaired. (Friction modifier), pour point depressant, rust inhibitor, metal deactivator, surfactant, antifoaming agent and the like may be blended.

  As the viscosity index improver, for example, polymethacrylate, dispersed polymethacrylate, olefin copolymer (for example, ethylene-propylene copolymer), dispersed olefin copolymer, styrene copolymer (for example, Styrene-diene copolymer, styrene-isoprene copolymer, etc.). The blending amount of these viscosity index improvers is about 0.5 to 15% by mass, preferably 1 to 10% by mass, based on the total amount of the composition, from the viewpoint of the blending effect.

  As the metallic detergent, any alkaline earth metal detergent used in lubricating oils can be used, for example, alkaline earth metal sulfonates, alkaline earth metal phenates, alkaline earth metal salicylates, and the like. And a mixture of two or more selected from the above. Alkaline earth metal sulfonates include alkaline earth metal salts of alkyl aromatic sulfonic acids obtained by sulfonated alkyl aromatic compounds having a molecular weight of 300 to 1,500, preferably 400 to 700, particularly magnesium salts and / or Or a calcium salt etc. are mentioned, A calcium salt is used preferably especially. Alkaline earth metal phenates include alkylphenols, alkylphenol sulfides, alkaline earth metal salts of Mannich reactants of alkylphenols, especially magnesium salts and / or calcium salts, among which calcium salts are particularly preferred. Examples of the alkaline earth metal salicylates include alkaline earth metal salts of alkyl salicylic acid, particularly magnesium salts and / or calcium salts, among which calcium salts are preferably used. The alkyl group constituting the alkaline earth metal detergent is preferably an alkyl group having 4 to 30 carbon atoms, more preferably a linear or branched alkyl group having 6 to 18 carbon atoms, which are linear or branched. But you can. These may also be primary alkyl groups, secondary alkyl groups or tertiary alkyl groups. Further, as the alkaline earth metal sulfonate, alkaline earth metal phenate and alkaline earth metal salicylate, the above alkyl aromatic sulfonic acid, alkylphenol, alkylphenol sulfide, Mannich reaction product of alkylphenol, alkylsalicylic acid, etc. are directly used as magnesium and / or Or it reacts with alkaline earth metal bases such as alkaline earth metal oxides and hydroxides of calcium, or once replaced with alkaline earth metal salts such as sodium salts and potassium salts, etc. Neutral alkaline earth metal sulfonates, neutral alkaline earth metal phenates and neutral alkaline earth metal salicylates as well as neutral alkaline earth metal sulfonates, neutral alkaline earth metal phenates obtained by Basic alkaline earth metal sulfonates, basic alkaline earth metal sulfonates obtained by heating an alkaline earth metal salicylate and excess alkaline earth metal salts or alkaline earth metal bases in the presence of water, Basic alkaline earth metal salicylates or neutral alkaline earth metal sulfonates, neutral alkaline earth metal phenates, and neutral alkaline earth metal salicylates in the presence of carbon dioxide. Also included are overbased alkaline earth metal sulfonates, overbased alkaline earth metal phenates, and overbased alkaline earth metal salicylates obtained by reacting.

In the present invention, the above-mentioned neutral salt, basic salt, overbased salt, and a mixture thereof can be used as the metal detergent, and in particular, overbased salicylate, overbased phenate, overbased sulfonate. A mixture of one or more of these and a neutral sulfonate is preferable in terms of cleanliness and wear resistance inside the engine.
Metal-based detergents are usually commercially available 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, preferably Is preferably 2.0 to 16% by mass.

  In the present invention, the total base number of the metal detergent is usually 10 to 500 mgKOH / g, preferably 15 to 450 mgKOH / g, and one or more selected from these can be used in combination. The total base number referred to here is 7. JIS K 2501 “Petroleum products and lubricants—neutralization number test method”. Means the total base number by potentiometric titration method (base number / perchloric acid method) measured according to the above.

  Further, the metal detergent of the present invention is not particularly limited in the metal ratio, and usually 20 or less can be used by mixing one or more kinds, but preferably the metal ratio is 3 or less. It is particularly preferable to use a metal-based detergent of 1.5 or less, particularly preferably 1.2 or less, as an essential component because it is excellent in oxidation stability, base number maintenance, high-temperature cleanliness, and the like. 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 metal elements include calcium, magnesium, and the like. The soap group means a sulfonic acid group, a phenol group, a salicylic acid group, and the like.

In the present invention, the content of the metal detergent is, based on the total amount of the composition, 1% by mass or less, preferably 0.5% by mass or less in terms of metal element, and further the sulfated ash content of the composition. In order to reduce the content to 0.8% by mass or less, the content is preferably 0.2% by mass or less. Further, the content of the metal detergent is preferably 0.005% by mass or more, more preferably 0.01% by mass or more in terms of metal element, oxidation stability, base number maintenance, high temperature In order to further improve the cleanliness, it is more preferably 0.05% by mass or more, and in particular by 0.08% by mass or more, a composition capable of maintaining the base number and the high temperature cleanliness for a long period can be obtained. Therefore, it is particularly preferable. The sulfated ash here refers to JIS K 2272 5. The value measured by the method prescribed in “Method for testing sulfated ash” is mainly due to the metal-containing additive.

As the ashless friction reducing agent, any compound usually used as an ashless friction reducing agent for lubricating oil can be used. For example, an alkyl group or an alkenyl group having 6 to 30 carbon atoms is included in the molecule. Examples include fatty acids, aliphatic alcohols, aliphatic ethers, aliphatic esters, aliphatic amines and aliphatic amides having at least one.
The amount of the ashless friction reducing agent added is preferably 0.2 to 1.0% by mass, more preferably 0.25 to 0.8% by mass from the viewpoint of the corrosion prevention effect and friction reducing effect on the metal material. More preferably, it is 0.3-0.6 mass%. If the amount is less than 0.2% by mass, a sufficient friction reducing effect cannot be obtained, and even if the amount exceeds 1.0% by mass, an effect commensurate with it cannot be obtained.

Examples of the pour point depressant include ethylene-vinyl acetate copolymer, condensate of chlorinated paraffin and naphthalene, condensate of chlorinated paraffin and phenol, polymethacrylate, polyalkylstyrene, and the like. Polymethacrylate having a molecular weight of about 5,000 to 50,000 is preferably used. These are used at a ratio of about 0.1 to 5% by mass based on the total amount of the composition.
Examples of the rust inhibitor include petroleum sulfonates, alkylbenzene sulfonates, dinonyl naphthalene sulfonates, alkenyl succinic acid esters, and polyhydric alcohol esters. The blending amount of these rust preventives is about 0.01 to 1% by mass, preferably 0.05 to 0.5% by mass, based on the total amount of the composition, from the viewpoint of the blending effect.

Examples of the metal deactivator (copper corrosion inhibitor) include benzotriazole, tolyltriazole, thiadiazole, imidazole, and pyrimidine compounds. Of these, benzotriazole compounds are preferred. By compounding a metal deactivator, metal corrosion and oxidative deterioration of engine parts can be suppressed. The compounding amount of these metal deactivators is preferably 0.01 to 0.1% by mass, more preferably 0.03 to 0.05% by mass, based on the total amount of the composition, from the viewpoint of the compounding effect.
Examples of antifoaming agents include silicone oils, fluorosilicone oils, fluoroalkyl ethers, and the like. From the viewpoint of balance between defoaming effect and economy, about 0.005 to 0.1% by mass based on the total amount of the composition. It is preferable to contain.

In the lubricating oil composition of the present invention, the sulfur content is preferably 0.3% by mass or less, more preferably 0.2% by mass or less, and still more preferably 0.1% by mass or less based on the total amount of the composition. It is below mass%. When the sulfur content is 0.3% by mass or less, the performance deterioration of the exhaust gas purification catalyst can be effectively suppressed.
In the lubricating oil composition of the present invention, the sulfated ash content is preferably 0.8% by mass or less, and more preferably 0.6% by mass or less. When the sulfated ash content is 0.8% by mass or less, in the diesel engine, the amount of ash deposited on the DPF filter is small, ash clogging of the filter is suppressed, and the life of the DPF is prolonged. The sulfated ash refers to the ash that is made by adding sulfuric acid to the carbonized residue generated by burning the sample and heating it to make it constant, and is usually used to know the approximate amount of metallic additives in the lubricating oil composition. Used for. Specifically, it is measured by a method defined in “5. Sulfated ash test method” of JIS K 2272.

  Since the lubricating oil composition for an internal combustion engine of the present invention can exhibit a high friction reducing effect at the time of new oil over a long period of time, it can be suitably used for an internal combustion engine such as a gasoline engine, a diesel engine, or a gas engine. Furthermore, even if a diesel suit is mixed in, this effect can be maintained, which is particularly suitable for a diesel engine.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.

[Examples 1 and 2 and Comparative Examples 1 to 4]
A lubricating oil composition having the composition shown in Table 1 was prepared, and the friction coefficient was measured in both the state of the new oil and the state after so-called NOx deterioration. From the results, the performance of the composition as a lubricating oil for internal combustion engines was evaluated.
The characteristics and properties of the base oil, the additive, and each composition (sample oil) were measured as follows.
(1) Kinematic viscosity of base oil and lubricating oil composition:
It was measured according to “Petroleum product kinematic viscosity test method” defined in JIS K 2283.
(2) Viscosity index of base oil:
It was measured according to “Petroleum product kinematic viscosity test method” defined in JIS K 2283.
(3) Sulfur content of base oil and lubricating oil composition:
The measurement was performed according to JIS K2541.
(4)% CA of base oil:
The ratio (percentage) of the aromatic component was calculated by the ring analysis ndM method.
(5) NOACK evaporation of base oil:
It measured based on JPI-5S-41-2004.

(5) Boron content:
It measured based on JPI-5S-38-92.
(6) Nitrogen content:
The measurement was performed according to JIS K2609.
(7) Molybdenum and phosphorus content:
It measured based on JPI-5S-38-92.
(8) Sulfated ash:
The measurement was performed according to JIS K2272.

(9) NOx degradation test:
Using a test machine of ISOT test (JIS K2514), nitrogen gas with NO content of 8000 ppm by volume was blown into the sample oil at a flow rate of 100 mL / min and air at a flow rate of 100 mL / min, and NOx deterioration A test was conducted. The test temperature is 140 ° C. and the test time is 24 hours.
(10) Friction coefficient (SRV, 80 ° C.):
The following four types of sample oils were prepared and the friction coefficient was measured.
[1] New oil (each composition having the composition shown in Table 1)
[2] Composition after performing NOx degradation test using new oil [3] Composition obtained by adding 0.5% by mass of carbon black to new oil [4] 0.5% by mass of carbon black to [2] In addition, the friction coefficient was measured on condition of the following using the SRV test machine (made by Optimol).
Test piece: (a) Disc: SUJ-2 material, (b) Cylinder: SUJ-2 material Amplitude: 1.5 mm
Frequency: 50Hz
Load: 400N
Temperature: 80 ° C

Moreover, the kind of each component used for preparation of a lubricating oil composition is as follows.
(1) Base oil: hydrorefined base oil, 40 ° C. kinematic viscosity 21 mm ² / s, 100 ° C. kinematic viscosity 4.5 mm ² / s, viscosity index 127,% CA 0.1 or less, sulfur content less than 20 mass ppm, NOACK evaporation of 13.3 mass%

(2) Polybutenyl succinic acid monoimide borate A: number average molecular weight of polybutenyl group 980, nitrogen content 1.76 mass%, boron content 2.1 mass%, B / N ratio 1.19, chlorine content An amount of 0.01% by mass or less The polybutenyl succinic acid monoimide borate A was produced as follows.
In a 1 L autoclave, 550 g of polybutene (Mn: 980), 1.5 g (0.005 mol) of cetyl bromide and 59 g (0.6 mol) of maleic anhydride were substituted with nitrogen and reacted at 240 ° C. for 5 hours. It was. The temperature was lowered to 215 ° C., unreacted maleic anhydride and cetyl bromide were distilled off under reduced pressure, and the temperature was lowered to 140 ° C. and filtered. The yield of the obtained polybutenyl succinic anhydride was 550 g, and the saponification value was 86 mgKOH / g. In a 1 L separable flask, 500 g of the obtained polybutenyl succinic anhydride, 17.4 g (0.135 mol) of aminoethylpiperazine (AEP), 10.3 g (0.10 mol) of diethylenetriamine (DETA), 14.6 g (0.10 mol) of ethylenetetramine (TETA) and 250 g of mineral oil were added and reacted at 150 ° C. for 2 hours under a nitrogen stream. The temperature was raised to 200 ° C., and unreacted AEP, DETA, TETA and produced water were distilled off under reduced pressure. The yield of the obtained polybutenyl succinimide was 750 g, and the base value (perchloric acid method) was 51 mgKOH / g. In a 500 mL separable flask, 150 g of the obtained polybutenyl succinimide and 20 g of boric acid were placed and reacted at 150 ° C. for 4 hours under a nitrogen stream. The generated water was distilled off under reduced pressure at 150 ° C, and the temperature was lowered to 140 ° C and filtered. The yield of the produced polybutenyl succinic acid monoimide borate A was 165 g, and the boron content was 2.1% by mass. Further, the polyalkylene polyamine having a ring structure at the terminal was 40 mol% of the whole polyalkylene polyamine.

(3) Polybutenyl succinic acid monoimide borate B: number average molecular weight of polybutenyl group 980, nitrogen content 1.90% by mass, boron content 0.8% by mass, B / N ratio 0.42.
Chlorine content 0.01% by mass or less This polybutenyl succinic acid monoimide boronated product B is the same as the method for producing polybutenyl succinic acid monoimide boronated product A except that the amount of boric acid added is 13 g. The reaction was carried out. The yield of the resulting polybutenyl succinic acid monoimide borate B was 161 g. Further, the polyalkylene polyamine having a ring structure at the terminal was 40 mol% of the whole polyalkylene polyamine.

(4) Polybutenyl succinic acid monoimide borate C: polybutenyl group number average molecular weight 980, nitrogen content 2.30% by mass, boron content 1.90% by mass, B / N ratio 0.83, chlorine content Amount of 0.01% by mass or less This polybutenyl succinic acid monoimide borate C is used in the production of polybutenyl succinic acid monoimide boride A without using aminoethylpiperazine (AEP) and diethylenetriamine (DETA). The same reaction was carried out except that 18 g (0.17 mol) and 25 g (0.17 mol) of triethylenetetramine (TETA) were used. The yield of the produced polybutenyl succinimide boride C was 165 g. In addition, the polyalkylene polyamine which has a ring structure at the terminal is not contained.

(5) Polybutenyl succinic acid monoimide borate D: number average molecular weight of polybutenyl group 980, nitrogen content 1.95% by mass, boron content 0.67% by mass, B / N ratio 0.34, chlorine content Amount of 0.01% by mass or less This polybutenyl succinic acid monoimide boronated substance D was used in the production method of polybutenyl succinic acid monoimide boronated substance A, without using aminoethylpiperazine (AEP), and diethylenetriamine (DETA). 18 g (0.17 mol) and 25 g (0.17 mol) of triethylenetetramine (TETA) were used, and the reaction was carried out in the same manner except that the amount of boric acid added was 13 g. The yield of the resulting polybutenyl succinimide boride D was 161 g. In addition, the polyalkylene polyamine which has a ring structure at the terminal is not contained.

(6) Molybdenum dithiocarbamate (MoDTC): SakuraLube 515 (manufactured by ADEKA Corporation), Mo content 10.0% by mass, sulfur content 11.5% by mass
(7) Phenol antioxidant: octadecyl-3- (3,5-di-tert-butyl 4-hydroxyphenyl) propionate (8) Amine antioxidant: dialkyldiphenylamine, nitrogen content 4.6% by mass
(9) Zinc dialkyldithiophosphate (ZnDTP): Zn content 9.0% by mass, phosphorus content 8.2% by mass, sulfur content 17.1% by mass, alkyl group; secondary butyl group and secondary Mixture of hexyl groups (10) Viscosity index improver: Styrene-isobutylene copolymer, mass average molecular weight 584,000, resin amount 10% by mass
(11) Metal-based detergent A: Overbased calcium phenate, base number (perchloric acid method) 255 mgKOH / g, calcium content 9.3 mass%, sulfur content 3.0 mass%
(12) Metal-based detergent B: calcium sulfonate, base number (perchloric acid method) 17 mg KOH / g, calcium content 2.4 mass%, sulfur content 2.8 mass%
(13) Polybutenyl succinic acid bisimide: (Number average molecular weight of polybutenyl group: 2000, nitrogen content: 2.10% by mass, chlorine content: 0.01% by mass or less) (14) Molybdenum antioxidant: Sakuralube S-710 (Made by ADEKA Co., Ltd.) Molybdenum content 10% by mass
(15) Ester friction modifier: glycerin monooleate (16) Other additives: metal deactivators, pour point depressants, antifoaming agents

〔Evaluation results〕
As can be seen from the results in Table 1, in Examples 1 and 2 using the lubricating oil composition of the present invention, new oil, oil after NOx deterioration test and carbon black were added in spite of low phosphorus amount and sulfated ash content. In any oil, the SRV friction coefficient is low and the friction reducing effect is excellent.
On the other hand, polybutenyl succinic acid monoimide boronated product B is blended in the sample oil of Comparative Example 1, but this compound has a low B / N ratio of 0.42, so it is used as an oil after NOx deterioration test. When carbon black is added, the SRV friction coefficient increases. In the sample oil of Comparative Example 2, polybutenyl succinic acid monoimide borate C is blended, but since this compound does not contain a polyalkylene polyamine having a ring structure at the terminal, the oil after the NOx deterioration test and After the NOx deterioration test, the SRV friction coefficient of the sample oil obtained by adding carbon black to the oil increases. The sample oil of Comparative Example 3 is blended with polybutenyl succinic acid monoimide borate D, but this compound does not contain a polyalkylene polyamine having a ring structure at the terminal, and also has a B / N ratio. Since it is as low as 0.34, the SRV friction coefficient of oil after NOx deterioration test, sample oil to which carbon black is added, and sample oil to which carbon black is added to oil after NOx deterioration test are extremely high. In Comparative Example 4, since MoDTC is not blended, the SRV friction coefficient is high and the friction reducing effect is not recognized.

The lubricating oil composition for internal combustion engines of the present invention is suitably used for internal combustion engines such as diesel engines and gasoline engines.

Claims (2)

A lubricating oil composition for an internal combustion engine, comprising: a base oil composed of mineral oil and / or synthetic oil; (A) a boride of a polyalkenyl succinimide compound; (B) molybdenum dithiocarbamate; and (C) zinc dialkyldithiophosphate. A thing,
The component (A) is (a) succinic acid substituted with a polyalkenyl group having a number average molecular weight of 500 to 5,000 or an anhydride thereof, and (b) 5 mol% or more of the whole has a piperazinyl group at the terminal. It is a boride of a polyalkenyl succinimide compound represented by the following formula (1) obtained by reacting with a polyalkylene polyamine, and the mass ratio (B / N ratio) of boron to nitrogen is 0.5 or more. The content of the component (A) is 0.01 to 0.1% by mass in terms of boron based on the total amount of the composition,

(In the formula, R ¹ is a polyalkenyl group having a number average molecular weight of 500 to 5,000, R ² , R ³ , R
⁴ and R ⁵ are each independently hydrogen or an alkyl group having 1 to 3 carbon atoms, q is an integer of 2 to 4, n is an integer of 0 to 3, r is an integer of 2 to 4, and A is an amino group or Piperazinyl group. )
The component (B) is molybdenum dithiocarbamate represented by the following formula (2), and the content of the component (B) is 0.01 to 0.08% by mass in terms of molybdenum based on the total amount of the composition. ,

(In the formula, R ^{6 to} R ⁹ each independently represents a hydrocarbyl group having ⁴ to 22 carbon atoms, and X ^{1 to} X ⁴ each represents a sulfur atom or an oxygen atom.)
The internal combustion engine lubricating oil composition, wherein the content of the component (C) is 0.01 to 0.09% by mass in terms of phosphorus on the basis of the total amount of the composition. The lubricating oil composition for an internal combustion engine according to claim 1,
A lubricating oil composition for an internal combustion engine, wherein the sulfur content is 0.3% by mass or less based on the total amount of the composition, and the sulfated ash content is 0.8% by mass or less based on the total amount of the composition.