JP2017179295A - Additive composition and lubricating oil composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an additive composition that is excellent in base oil solubility, base number retention, and high-temperature purification, and also prevents the contamination of peripheral components.SOLUTION: An additive composition has a metal salt of a saturated aliphatic monocarboxylic acid having a C8-C32 branched alkyl group.SELECTED DRAWING: None

Description

  The present invention relates to an additive composition and a lubricating oil composition containing the additive composition, for example, an additive composition used in an internal combustion engine, and a lubricating oil composition.

In recent years, strict regulations on exhaust gas have been introduced one after another in the automobile industry for the purpose of reducing environmental load, and exhaust gas aftertreatment devices have been developed. In addition to carbon dioxide, which is a global warming substance, the exhaust gas contains particulate matter (PM), hydrocarbons, carbon monoxide, nitrogen oxides (NOx), etc., which are harmful substances. And NOx limits are getting stricter. As a measure for reducing these emissions, a gasoline engine is equipped with a three-way catalyst, and a diesel engine is equipped with a diesel particulate filter (DPF).
Furthermore, in a diesel engine, the combustion peak temperature may be lowered due to a delay in fuel injection timing or the like in order to reduce NOx. In such a case, the exhaust gas aftertreatment device leads to an increase in black smoke and PM. Must be installed. Use of a filter such as a PM trap or an oxidation catalyst is being considered for this exhaust gas aftertreatment device.
As described above, in an internal combustion engine of an automobile, introduction of an exhaust gas treatment device having a filter has been promoted for the purpose of purifying exhaust gas.

  On the other hand, conventionally, metallic detergents are widely used as detergent dispersants in lubricating oils for internal combustion engines. As metal-based detergents, alkali metal or alkaline earth metal sulfonates, phenates, salicylates, phosphonates, and overbased products thereof are generally used. The metal contained in the lubricating oil becomes a factor that causes clogging of the various filters described above. Therefore, in recent years, attempts have been made to reduce the amount of metallic detergent blended.

  Moreover, as disclosed in Patent Document 1, a lubricating oil composition containing a carboxylic acid metal salt such as overbased calcium oleate for the purpose of providing a low ash (low metal content) lubricating oil. Is also known. Further, as the carboxylic acid metal salt, as disclosed in Patent Document 2, for example, iron 2-ethylhexylate, nickel 2-ethylhexylate, indium 2-ethylhexylate, etc. are burned in an amount of less than 0.1% by mass. It is also known to be incorporated into lubricating oil compositions as an accelerator.

JP 2004-331973 A JP 2002-146379 A

However, as described above, when using a metal detergent such as sulfonate, phenate, salicylate, phosphonate, etc., the amount of the compound is reduced, the initial base number, the high-temperature cleanability, etc. tend to be lowered. In addition, these metallic detergents tend to generate non-volatile residues when burned in the internal combustion engine. Therefore, for example, when used for lubricating oil for internal combustion engines, even if the blending amount is small, it becomes a factor that causes clogging of the filter of the exhaust gas apparatus.
On the other hand, carboxylic acid metal salts disclosed in Patent Documents 1 and 2 have low oil solubility and may not be sufficiently dissolved in mineral oil or the like used for lubricating oil, and may be difficult to use practically. .

  The present invention has been made in view of the above circumstances, and the problem of the present invention is that it has high solubility in base oil and high temperature cleanliness, and further suppresses the generation of nonvolatile residues during combustion. Another object of the present invention is to provide an additive composition and a lubricating oil composition containing the additive composition, which can easily prevent contamination of peripheral parts such as filter clogging.

As a result of intensive studies, the present inventors have found that the above-mentioned problems can be solved by using a specific fatty acid metal salt as the metal detergent, and have completed the present invention described below. The present invention provides the following [1] to [3].
[1] An additive composition comprising a metal salt of a saturated aliphatic monocarboxylic acid having a branched alkyl group having 8 to 32 carbon atoms.
[2] A lubricating oil composition comprising a base oil and the additive composition according to the above [1].
[3] An additive composition containing a saturated aliphatic monocarboxylic acid metal salt obtained by mixing a saturated aliphatic monocarboxylic acid having a branched alkyl group having 8 to 32 carbon atoms and a metal compound and reacting them. A method for producing an additive composition to obtain a product.

  In the present invention, an additive that has high solubility in base oil and high-temperature cleanability, and further suppresses the generation of non-volatile residues during combustion, thereby making it easier to prevent contamination of peripheral parts such as filter clogging. Compositions and lubricating oil compositions can be provided.

Hereinafter, the present invention will be described using embodiments.
<Additive composition>
An additive composition according to an embodiment of the present invention includes a metal salt of a saturated aliphatic monocarboxylic acid having a branched alkyl group having 8 to 32 carbon atoms (hereinafter also simply referred to as “long-chain branched carboxylic acid”). It is a waste. Since such an additive composition can be easily dissolved in a base oil of a lubricating oil such as mineral oil, it can be practically used as a lubricating oil additive. And it becomes possible to improve the base number maintenance property and high temperature cleanliness | purity of the lubricating oil composition which mix | blended the additive composition of this embodiment. Furthermore, since the combustibility is good and the non-volatile residue at the time of combustion is hardly generated, it is easy to prevent contamination of peripheral parts, for example, clogging of a filter provided in the internal combustion engine.

On the other hand, when the number of carbon atoms of the branched alkyl group is less than 7, the additive composition has low solubility and is difficult to dissolve in the base oil, and may not exhibit the various functions described above. Further, when the number of carbon atoms is 33 or more, it is difficult to obtain carboxylic acid practically, and there is a possibility that the various functions described above cannot be exhibited, such as a decrease in base number. The long-chain branched carboxylic acid is a compound represented by the structural formula RCOOH, and R is a branched alkyl group having 8 to 32 carbon atoms.
The carbon number of the branched alkyl group of the long-chain branched carboxylic acid is preferably 11 to 23, more preferably 15 to 19, and particularly preferably 17. By making the number of carbons within these ranges, the solubility of the additive composition is enhanced, and the various functions described above are easily exhibited by an appropriate amount of the additive composition.

Examples of the metal that forms a metal salt with a long-chain branched carboxylic acid include a metal belonging to Group 1 of the periodic table (that is, an alkali metal) or a metal belonging to Group 2 of the periodic table. Examples of lithium, sodium, potassium, and Group 2 metals include beryllium, magnesium, and calcium.
Among these metals, lithium, sodium and magnesium are preferable, and sodium and magnesium are more preferable. In particular, sodium is more preferable from the viewpoint that it is easy to improve the base number maintenance property and the high-temperature cleanability with a small additive composition addition amount. Further, magnesium is more preferable from the viewpoint of suppressing generation of non-volatile residues during combustion and facilitating contamination of peripheral parts.
The said metal may be used individually by 1 type, and may be used in combination of 2 or more type.

More specifically, examples of the long-chain branched carboxylic acid include compounds represented by the following formula (1).

In the formula (1), n is 0 or 1, R ¹ is a hydrogen atom, or a linear or branched alkyl group having 1 to 18 carbon atoms, R ² is a hydrogen atom or a methyl group, and R ³ is linear or It is a branched alkyl group having 1 to 18 carbon atoms. However, when R ¹ is a hydrogen atom, at least R ² is a methyl group, or R ³ is a branched alkyl group.
Here, in the formula (1), both the number of carbon atoms of R ¹ is 4 to 14, preferably the total number of carbon atoms of R ² and R ³ is 2 to 12, the number of carbon atoms in R ¹ is 4 both are 10, more preferably the total number of carbon atoms of R ² and R ³ is 2-8, both the number of carbon atoms in R ¹ is 6-8, the total number of carbon atoms in R ² and R ³ is 4 6 is more preferable. N is preferably 0.

More specifically, examples of the compound represented by the formula (1) include compounds represented by the following formulas (2) to (5).

In the formula (2), R ^{11 to} R ¹³ and R ^{15 to} R ¹⁷ are each independently a hydrogen atom or a methyl group, and R ¹⁴ and R ¹⁸ are each independently a hydrogen atom or a linear or branched carbon. It is a C1-C14 alkyl group. However, R ^{11 to} R ¹³ and R ^{15 to} R ¹⁷ may be the same as or different from each other. R ¹⁴ and R ¹⁸ may be the same as or different from each other.
Among the compounds of formula (2), the total carbon number of R ^{11 to} R ¹⁴ is 1 to 11, and the total carbon number of R ^{15 to} R ¹⁸ is preferably 1 to 11, and R ^{11 to} R ^14. of the total number of carbon atoms is 1 to 7, together with the total number of carbon atoms of R ¹⁵ to R ¹⁸ is 1-7, more preferably the total number of carbon atoms of R ¹¹ to R ¹⁸ is 3 to 14, R ¹¹ to R More preferably, the total carbon number of ¹⁴ is 3-5, the total carbon number of R ¹⁵ -R ¹⁸ is 3-5, and the total carbon number of R ¹¹ -R ¹⁸ is 6-10, , R ^{11 to} R ¹⁸ are particularly preferably 8 in total.
When the total number of carbon atoms of R ^{11 to} R ^{14 and} the total number of carbon atoms of R ^{15 to} R ¹⁸ are within a certain range, the solubility of the additive composition is increased and the above-described amount of the additive composition is appropriate. It becomes easy to demonstrate various functions.

In the formula (3), R ²¹ and R ²² both represent a branched or straight chain alkyl group having 1 to 18 carbon atoms, and the total number of these carbon atoms is 2 to 26. R ²¹ and R ²² may be the same as or different from each other. In the formula (3), R ²¹ and R ²² are both branched or linear alkyl groups having 1 to 10 carbon atoms, and the total number of these carbon atoms is preferably 5 to ¹⁷ , R ²¹ , R ²² is a branched or straight chain alkyl group having 3 to 8 carbon atoms, the total number of these carbon atoms is more preferably 9 to 13, and the total number of carbon atoms is particularly preferably 11.

In the formula (4), m represents an integer of 5 to 29, preferably 8 to 20, more preferably 12 to 16, and particularly preferably 14.

In the formula (5), k represents an integer of 2 to 26, preferably 5 to 17, more preferably 9 to 13, and particularly preferably 11.
In the formulas (4) and (5), m and k each means that m or k methylene groups (—CH ₂ —) are linked in a straight chain.
The metal that forms the metal salt with the long-chain branched carboxylic acid represented by each of the above formulas (1) to (5) is as described above.

  Of the compounds represented by the formulas (2) to (5), the long-chain branched carboxylic acid is preferably a compound represented by the formula (2). Therefore, the metal salt of the long-chain branched carboxylic acid is preferably one or more selected from compounds represented by the following formulas (6) and (7).

In formulas (6) and (7), R ^{11 to} R ¹⁸ are as described above. M is an alkali metal, specifically lithium, sodium, or potassium. L is a metal of Group 2 of the periodic table, specifically, beryllium, magnesium, or calcium. Among these, M is preferably lithium or sodium, and more preferably sodium. L is preferably magnesium.
As the metal salt of the long-chain branched carboxylic acid, the compound of the formula (6) may be used alone, the compound of the formula (7) may be used alone, or the compound of the formula (6) You may use the compound of Formula (7) together.

Specific examples of the long-chain branched carboxylic acid include 2-butyloctanoic acid, 2-hexyldecanoic acid, 2-heptylundecanoic acid, 2,2,4,8,10,10-hexamethylundecane-5-carboxylic acid. 2-octyldecanoic acid, 2-hexyldecanoic acid, 3,13-dimethylpentadecane-7-carboxylic acid, 2,6,10,14-tetramethylpentadecane-7-carboxylic acid, 2-octyldodecanoic acid, 2- Examples include decyltetradecanoic acid, 2-dodecylhexadecanoic acid, and 2-tetradecyloctadecanoic acid.
Among these, 2-hexyldecanoic acid, 2-heptylundecanoic acid, 2,2,4,8,10,10-hexamethylundecane-5-carboxylic acid, 2-octyldecanoic acid, 2-hexyldecanoic acid, 3 , 13-dimethylpentadecane-7-carboxylic acid, 2,6,10,14-tetramethylpentadecane-7-carboxylic acid, 2-octyldodecanoic acid are more preferred, 2-heptylundecanoic acid, 2,2,4,8 , 10,10-hexamethylundecane-5-carboxylic acid is more preferred, and 2,2,4,8,10,10-hexamethylundecane-5-carboxylic acid is particularly preferred.
The long chain branched carboxylic acid may be used alone or in combination of two or more.

  The long-chain branched carboxylic acid is preferably 1 or more, more preferably 1.2 or more, and more preferably 2 or more from the viewpoint of solubility of the additive composition in the base oil. Is more preferable. In this specification, the degree of branching is an average value of the total number of tertiary carbons and quaternary carbons contained in one molecule. The upper limit of the degree of branching is not particularly limited, but is preferably 5 or less.

The additive composition of the present embodiment may include a metal salt formed of a long-chain branched carboxylic acid and a metal, and may be composed of the metal salt alone, but includes other components. May be. Examples of such components include various compounds that can be contained as impurities in the long-chain branched carboxylic acid, and examples include carboxylic acids other than the long-chain branched carboxylic acid. Examples of the carboxylic acid include linear aliphatic carboxylic acid, unsaturated aliphatic carboxylic acid, and saturated aliphatic monocarboxylic acid having a branched alkyl group having 7 or less carbon atoms.
That is, the carboxylic acid in the additive composition may be composed of a long-chain branched carboxylic acid, but a long-chain branched carboxylic acid that can form a metal salt as long as it does not affect the effects of the present invention. Other carboxylic acids may be included. The amount of carboxylic acid other than the long-chain branched carboxylic acid is, for example, 20% by mass or less, preferably 10% by mass or less, more preferably 5% by mass or less, based on the total amount of carboxylic acid in the additive composition.
The additive composition may be appropriately diluted with mineral oil, synthetic oil or the like used as a base oil in the lubricating oil composition. The mineral oil for diluting the additive composition is preferably used as a reaction solvent as described later.

  Furthermore, the carboxylic acid (long-chain branched carboxylic acid and carboxylic acid other than the long-chain branched carboxylic acid) in the additive composition does not necessarily need to form a metal salt with the above metal. A part of the branched carboxylic acid may be present in the additive composition or the lubricating oil composition described later as the carboxylic acid without becoming a metal salt. Similarly, the metal for forming a metal salt (specifically, a metal-based compound described later) does not need to form a metal salt with a carboxylic acid, and part of the metal forms a salt with another compound. Alternatively, it may be present in an additive composition or a lubricating oil composition described later in a state other than a metal salt such as a metal hydroxide.

In the additive composition, the equivalent ratio of the long-chain branched carboxylic acid to the metal in the additive composition is 1 or a value close to 1 (for example, 0.95 to 1.10, more preferably 0.97). To 1.03). Thereby, the long chain branched carboxylic acid and metal which do not form a metal salt can be reduced as much as possible.
However, as described above, when a carboxylic acid other than the long-chain branched carboxylic acid is included as an impurity, the total carboxylic acid with respect to the metal (that is, the total of the long-chain branched carboxylic acid and the other carboxylic acid) is within the above range. It may be adjusted so as to be inside.

(Method for producing additive composition)
The additive composition of the present embodiment can be produced, for example, by mixing a long-chain branched carboxylic acid and a metal compound and reacting them. The metal-based compound includes the above-described metal, and examples thereof include a metal hydroxide and a metal alkoxide.
Examples of the metal hydroxide include a hydroxide of a group 1 metal (alkali metal) of the periodic table, a metal hydroxide of a group 2 of the periodic table, and more specifically, lithium hydroxide, water Examples include sodium oxide, potassium hydroxide, beryllium hydroxide, magnesium hydroxide, calcium hydroxide, and the like.
Examples of the metal alkoxide include alkali metal alkoxides, group 2 metal alkoxides, and the like. Specifically, lithium methoxide, lithium ethoxide, sodium methoxide, sodium ethoxide, magnesium methoxide. , Magnesium ethoxide, potassium methoxide, potassium ethoxide, calcium methoxide, calcium ethoxide and the like.
When the additive composition is produced, as described above, a compound other than the long-chain branched carboxylic acid and the metal compound may be mixed within a range that does not affect the effect of the present invention. . Examples of such compounds include carboxylic acids other than long-chain branched carboxylic acids as described above.

In this production method, the ratio (mixing ratio) to the charged amount of the long-chain branched carboxylic acid to the charged amount of the metal (that is, the metal component derived from the metal-based compound) is 1 or close to the equivalent ratio. Although it is better to adjust, when the solubility of the metal compound in the reaction solvent is poor, the metal compound may be charged excessively. From these viewpoints, the mixing ratio is preferably 0.90 to 2.00, more preferably 0.95 to 1.10, and still more preferably 0.97 to 1.03. However, when using an excessive amount of the metal compound, the equivalent ratio of the long-chain branched carboxylic acid to the metal in the additive composition is removed as described above by removing the metal compound by filtration or the like after the reaction. It is better to adjust to 1 or a value close to 1.
As described above, when a carboxylic acid other than the long-chain branched carboxylic acid is mixed as an impurity, the mixing ratio is the sum of the carboxylic acids relative to the metal (that is, the long-chain branched carboxylic acid and the other chain). What is necessary is just to adjust so that the sum total of carboxylic acid may become in the said range.

The reaction between the long-chain branched carboxylic acid and the metal compound is preferably performed in the presence of a reaction solvent. As the reaction solvent, for example, water, methanol, ethanol, propanol, butanol, toluene, xylene, tetrahydrofuran, dioxane, mineral oil, or a mixed solvent containing two or more of these is used.
The reaction temperature is preferably -20 to 180 ° C, more preferably 10 to 180 ° C. The reaction time is not particularly limited, but is usually 10 minutes to 36 hours, preferably 30 minutes to 24 hours.
The reaction solvent may be removed from the additive composition obtained by distillation or the like, but it may not be removed. For example, when the reaction solvent is a mineral oil that can be used as the base oil described later, the reaction solvent contained in the additive composition can be used as it is as the base oil of the lubricating oil composition without being removed. Become.

<Lubricating oil composition>
The lubricating oil composition according to one embodiment of the present invention contains a base oil and the additive composition described above. In the lubricating oil composition, the metal content derived from the additive composition is preferably 5 to 1000 ppm by mass based on the total amount of the lubricating oil composition. As for the said metal content, it is more preferable that it is 50-600 mass ppm, and it is further more preferable that it is 80-300 mass ppm.
By setting the metal amount to be equal to or higher than these lower limit values, it becomes easy to improve the base number maintaining property and the high temperature cleanability. Moreover, by setting it as these upper limits or less, it becomes easy to suppress generation | occurrence | production of the non-volatile residue at the time of combustion, and it becomes easy to prevent contamination of peripheral components, such as clogging of a filter.

(Base oil)
There is no restriction | limiting in particular as base oil used for a lubricating oil composition, Arbitrary things can be suitably selected and used from the mineral oil and synthetic oil which can be used as a base oil of lubricating oil.
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. Examples include mineral oil refined by one or more treatments such as wax, hydrorefining, and the like, and base oils produced by isomerizing wax such as GTL WAX (Gas Liquid Wax).
Synthetic oils include, for example, polyα-olefins such as polybutene, α-olefin homopolymers and copolymers (for example, ethylene-α-olefin copolymers), such as polyol esters, dibasic acid esters, and phosphate esters. And various esters, for example, various ethers such as polyphenyl ether and polyglycol, alkylbenzene, alkylnaphthalene and the like. As the base oil, it is preferable to use mineral oil.
As base oil, mineral oil may be used independently and may be used in combination of 2 or more type. Moreover, synthetic oil may be used independently and may be used in combination of 2 or more type. Furthermore, one or more mineral oils and one or more synthetic oils may be used in combination.
In the lubricating oil composition, the base oil is usually contained in an amount of 60% by mass or more, preferably 70% by mass or more, more preferably 80% by mass or more based on the total amount of the lubricating oil composition.

The viscosity of the base oil is not particularly limited, but the kinematic viscosity at 100 ° C. is preferably 1.5 to 50 mm ² / s, more preferably ² to 30 mm ² / s, still more preferably 3 to 15 mm ² / s. It is a range.
When the kinematic viscosity at 100 ° C. is 2 mm ² / s or more, evaporation loss is small, and when it is 30 mm ² / s or less, power loss due to viscous resistance is suppressed.
Furthermore, the viscosity index of the base oil is preferably 70 or more, more preferably 90 or more, and still more preferably 100 or more. By making the viscosity index of the base oil within these ranges, it becomes easy to improve the viscosity characteristics of the lubricating oil composition.

(Succinimide derivative)
The lubricating oil composition preferably contains a succinimide derivative in addition to the base oil and the additive composition. The succinimide derivative is an ashless dispersant, and when used in combination with the above additive composition, it becomes easier to improve the high-temperature cleanability.
The succinimide derivative preferably has an alkyl group having a number average molecular weight of 300 to 3000 or an alkenyl group having a number average molecular weight of 300 to 3000.
As the succinimide derivative, a boronated boronated succinimide derivative may be used, or a non-borated nonborated succinimide derivative may be used. By using a boronated succinimide derivative, the high temperature cleanliness can be improved more easily. In addition, when a non-boronated succinimide derivative is used, it is easy to suppress the generation of non-volatile residues during combustion, and the effect of suppressing contamination of peripheral parts such as filter clogging can be easily enhanced.

Preferable specific examples of the succinimide derivative are selected from non-boronated succinic acid monoimide represented by the following formula (8), non-boronated succinic acid bisimide represented by the following formula (9), and borated compounds thereof. 1 type or 2 types or more are mentioned.

R ³¹ , R ³² and R ³³ in formulas (8) and (9) each independently represent an alkyl group or alkenyl group having a number average molecular weight of 300 to 3,000. R ³² and R ³³ may be the same as or different from each other. r represents an integer of 1 to 10. s shows the integer of 0-10.
The succinimide derivatives represented by the above formulas (8) and (9) are easy to obtain good cleanliness and easily function as a dispersant. Moreover, the solubility to base oil becomes favorable because a number average molecular weight becomes in the said range.

R ³¹ , R ³² and R ³³ are preferably a polybutenyl group. Examples of the polybutenyl group include 1-butene, isobutene, or those obtained by polymerizing both. The number average molecular weight of R ³¹ , R ³² and R ³³ is preferably 500 to 4000, more preferably 800 to 4000. r is preferably an integer of 2 to 4. S is preferably an integer of 2 to 5.
Although there is no limitation in particular as a manufacturing method of the succinimide derivative shown by said Formula (8) and (9), it can manufacture by a well-known method. For example, a polyalkenyl succinic acid obtained by reacting a polyolefin such as polybutene with maleic anhydride at 100 to 200 ° C. or an anhydride thereof, or a hydrogenated product thereof, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, It can be obtained by reacting with a polyamine such as pentaethylenehexamine and hexaethyleneheptamine.

The boronated succinimide derivative is obtained by allowing a boron compound to act on various non-borated succinimide derivatives. Examples of the boron compound include boric acid, borates, and borate esters. Examples of the boric acid include orthoboric acid, metaboric acid, and paraboric acid. Examples of the borate include ammonium salts such as ammonium borate such as ammonium metaborate, ammonium tetraborate, ammonium pentaborate and ammonium octaborate. Examples of boric acid esters include esters of boric acid and alkyl alcohols (preferably having 1 to 6 carbon atoms) such as monomethyl borate, dimethyl borate, trimethyl borate, monoethyl borate, diethyl borate, and triethyl borate. Preferred examples include monopropyl borate, dipropyl borate, tripropyl borate, monobutyl borate, dibutyl borate and tributyl borate.
The mass ratio (B / N) of the boron content (B) and the nitrogen content (N) in the boronated succinimide derivative is preferably 0.1 to 3, and preferably 0.2 to 1.5. It is preferable.

Although content in particular of a succinimide derivative in a lubricating oil composition is not restrict | limited, 0.1-30 mass% is preferable with respect to lubricating oil composition whole quantity, 1.0-30 mass% is more preferable, 1. 0-25 mass% is more preferable. If it is 0.1% by mass or more, good cleanability and dispersibility can be obtained, and if it is 30% by mass or less, effects of cleanliness and dispersibility commensurate with the content can be obtained.
The succinimide derivative preferably includes a boronated succinimide derivative.
Further, a mixture of a boronated succinimide derivative and a non-boronated succinimide derivative is more preferable, and includes a non-boronated succinic acid bisimide represented by the formula (9) and a boronated product of the succinic acid bisimide represented by the formula (9). More preferably. When these mixtures are used, it becomes easier to prevent the generation of nonvolatile residues during combustion while further improving the high temperature cleanliness.
When the succinimide derivative contains a boronated succinimide derivative, the boron amount derived from the succinimide derivative is preferably 0.01 to 0.50% by mass based on the total amount of the lubricating oil composition. The content is more preferably 0.02 to 0.30% by mass, and further preferably 0.025 to 0.20% by mass.

(Antioxidant)
The lubricating oil composition preferably contains an antioxidant in addition to the base oil and additive composition. The antioxidant is more preferably used in combination with the above succinimide derivative. Examples of the antioxidant include amine-based antioxidants, phenol-based antioxidants, sulfur-based antioxidants, phosphorus-based antioxidants, etc. Among them, amine-based antioxidants and phenol-based antioxidants are preferable.

  Examples of amine-based antioxidants include monoalkyl diphenylamines having an alkyl group having 4 to 12 carbon atoms such as mono-t-butyldiphenylamine, monooctyldiphenylamine, and monononyldiphenylamine; 4,4′-dibutyldiphenylamine, 4,4 '-Dipentyldiphenylamine, 4,4'-dihexyldiphenylamine, 4,4'-diheptyldiphenylamine, 4,4'-dioctyldiphenylamine, 4,4'-dinonyldiphenylamine, 4-butyl-4'-octyldiphenylamine, etc. Dialkyldiphenylamine having 4 to 12 carbon atoms in each alkyl group; tetrabutyldiphenylamine, tetrahexyldiphenylamine, tetraoctyldiphenylamine, tetranonyldiphenylamine, di (2,4-diethyl) Phenyl) amine, di (2-ethyl-4-nonylphenyl) amine and the like, polyalkyldiphenylamine having 3 or more alkyl groups, each alkyl group having 1 to 10 carbon atoms; methylphenyl-α-naphthylamine, ethyl Phenyl-α-naphthylamine, butylphenyl-α-naphthylamine, hexylphenyl-α-naphthylamine, heptylphenyl-α-naphthylamine, octylphenyl-α-naphthylamine, nonylphenyl-α-naphthylamine, t-dodecylphenyl-α-naphthylamine, etc. And phenyl-α-naphthylamines exemplified by alkylphenyl-α-naphthylamine or phenyl-α-naphthylamine having at least one alkyl group having 1 to 12 carbon atoms.

Examples of phenolic antioxidants include monophenolic antioxidants and bisphenolic antioxidants.
Monophenol antioxidants include n-octyl-3- (3,5-di-t-butyl 4-hydroxyphenyl) propionate, 6-methylheptyl-3- (3,5-di-t-butyl- Alkyl-3- (3,5-di-t-butyl-4-hydroxy) such as 4-hydroxyphenyl) propionate, n-octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate Phenyl) propionate (alkyl groups include those having 4 to 20 carbon atoms, preferably 8 to 18 carbon atoms); 2,6-di-t-butyl-4-methylphenol, 2,6 2,6-di-t-butyl-4-alkylphenol (C1-C4 of alkyl group) such as di-t-butyl-4-ethylphenol; 2,4-dimethyl-6-t- Butylphenol, 2,6-di -t- amyl -p- cresol.

  As bisphenol antioxidants, 4,4′-methylenebis (2,6-di-t-butylphenol), 4,4′-bis (2,6-di-t-butylphenol), 4,4′- Bis (2-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 4 , 4′-butylidenebis (3-methyl-6-tert-butylphenol), 4,4′-isopropylidenebis (2,6-di-tert-butylphenol), 2,2′-methylenebis (4-methyl-6- Nonylphenol), 2,2'-isobutylidenebis (4,6-dimethylphenol), 2,2'-methylenebis (4-methyl-6-cyclohexylphenol), 4,4 ' Thiobis (2-methyl-6-tert-butylphenol), 4,4′-thiobis (3-methyl-6-tert-butylphenol), 2,2′-thiobis (4-methyl-6-tert-butylphenol), bis (3-methyl-4-hydroxy-5-tert-butylbenzyl) sulfide, bis (3,5-di-tert-butyl-4-hydroxybenzyl) sulfide, thiodiethylenebis [3- (3,5-di- t-butyl-4-hydroxyphenyl) propionate] and the like.

  An antioxidant may be used individually by 1 type and may use 2 or more types together. Moreover, it is preferable to use together an amine antioxidant and a phenolic antioxidant as antioxidant. The content of the antioxidant is preferably 0.05 to 5% by mass, more preferably 0.1 to 4% by mass, and still more preferably 0.1 to 3% by mass, based on the total amount of the lubricating oil composition.

(Other additives)
The lubricating oil composition may contain various additives (other additives) other than the above-described additives. As such other additives, it is preferable to use one or more selected from antiwear agents, extreme pressure agents, viscosity index improvers, antifoaming agents, and metal deactivators. The content of other additives is usually about 20% by mass or less, preferably 0.1 to 15% by mass, based on the total amount of the lubricating oil composition.
Examples of the antiwear agent or extreme pressure agent include sulfur-containing compounds, phosphorus-containing compounds, sulfur and phosphorus-containing compounds, and ashless compounds are preferred. Specifically, sulfur-containing compounds such as disulfides, sulfurized olefins, sulfurized fats and oils, sulfurized esters, thiocarbonates, thiadiazoles; phosphites, phosphate esters, phosphonate esters, and these Phosphorus-containing compounds such as amine salts of these; and sulfur and phosphorus-containing compounds such as thiophosphites, thiophosphonates, and amine salts thereof, among which thiadiazoles are preferred. Examples of ash-based ones include zinc dithiophosphate, zinc phosphate, zinc dithiocarbamate, molybdenum dithiocarbamate, molybdenum dithiophosphate, and metal salts of those listed above as ashless ones.

Examples of thiadiazoles include 2,5-bis (n-hexyldithio) -1,3,4-thiadiazole, 2,5-bis (n-octyldithio) -1,3,4-thiadiazole, 2,5 -Bis (n-nonyldithio) -1,3,4-thiadiazole, 2,5-bis (1,1,3,3-tetramethylbutyldithio) -1,3,4-thiadiazole, 3,5-bis ( n-hexyldithio) -1,2,4-thiadiazole, 3,6-bis (n-octyldithio) -1,2,4-thiadiazole, 3,5-bis (n-nonyldithio) -1,2,4 -Thiadiazole, 3,5-bis (1,1,3,3-tetramethylbutyldithio) -1,2,4-thiadiazole, 4,5-bis (n-octyldithio) -1,2,3-thiadiazole , 4,5-bis (n Nonyldithio) -1,2,3-thiadiazole, 4,5-bis (1,1,3,3-tetramethylbutyl dithio) -1,2,3-bis such thiadiazole (alkyldithio) and thiadiazole.
The antiwear agent or extreme pressure agent may be used alone or in combination of two or more selected from the above. The content of the antiwear or extreme pressure agent is preferably 0.005 to 2% by mass, more preferably 0.01 to 1.5% by mass, and 0.01 to 1% by mass based on the total amount of the lubricating oil composition. Is more preferable.

The lubricating oil composition may contain a viscosity index improver to improve the viscosity index of the lubricating oil composition. Viscosity index improvers include polymethacrylates; olefin copolymers such as ethylene-propylene copolymers; styrene copolymers such as styrene-diene copolymers, styrene-isoprene copolymers, and styrene-isobutylene copolymers. Among these, an olefin copolymer is preferable.
The content of the viscosity index improver is appropriately adjusted according to the weight average molecular weight and the desired viscosity index value, but is preferably in the range of 0.5 to 15% by mass based on the total amount of the lubricating oil composition. Preferably it is the range of 1-10 mass%.
Examples of the antifoaming agent include silicone-based, fluorosilicone-based, and fluoroalkyl ether-based. Among these, a silicone-based antifoaming agent is preferable. The content of the antifoaming agent is preferably in the range of 0.005 to 0.5% by mass, more preferably 0.01 to 0.5% by mass, based on the total amount of the lubricating oil composition, from the viewpoint of balance between the defoaming effect and economy. The range is 0.2% by mass.
Examples of the metal deactivator include benzotriazole, tolyltriazole, thiadiazole, and imidazole compounds, and among these, benzotriazole is preferable. The content of the metal deactivator is preferably in the range of 0.01 to 3% by mass, more preferably in the range of 0.01 to 1% by mass, based on the total amount of the lubricating oil composition.
However, the lubricating oil composition may contain other additives than the above-mentioned additives, such as pour point depressant, rust preventive agent, friction modifier, metal system. A cleaning agent etc. are mentioned.

  The lubricating oil composition of the present embodiment preferably has a low ash content in order to more effectively prevent contamination of peripheral parts such as filter clogging. Specifically, the lubricating ash content of the lubricating oil composition However, it is preferable that it is 0.3 mass% or less. The sulfated ash content is more preferably 0.2% by mass or less, and further preferably 0.15% by mass or less. In addition, sulfate ash means the value measured based on JISK2272: 1998.

(Method for producing lubricating oil composition)
A method for producing a lubricating oil composition according to an embodiment of the present invention includes a metal salt of a long-chain branched carboxylic acid obtained by mixing a long-chain branched carboxylic acid and a metal compound and reacting them. The additive composition prepares a lubricating oil composition blended with the base oil.
In this production method, an additive composition containing a metal salt of a long-chain branched carboxylic acid obtained by reacting a long-chain branched carboxylic acid and a metal compound in advance is blended with a base oil to obtain a lubricating oil composition. It is preferable. However, a long-chain branched carboxylic acid and a metal compound may be blended in the base oil to form a metal salt in the base oil using the base oil as a reaction solvent.
Further, as described above, a succinimide derivative, an antioxidant, and other additives may be appropriately added to the base oil.
In addition, since the blending amount of each component used in this production method, details, details of the lubricating oil composition obtained by this production method, and the like are the same as the content described above and other detailed explanations, Description of is omitted.

(How to use the lubricating oil composition)
Although the lubricating oil composition of this embodiment can be used for the purpose of lubricating between members of various devices, it is preferably used as a lubricating oil composition for internal combustion engines such as automobiles. Although it does not specifically limit as an internal combustion engine, A gasoline engine, a diesel engine, a gas engine etc. are mentioned. The internal combustion engine is preferably equipped with an exhaust gas treatment device having a filter such as a three-way catalyst, a DPF, a PM trap, or an oxidation catalyst.

EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not restrict | limited at all by these examples.
In the present invention, each physical property measurement and evaluation method is as follows.

(1) Kinematic viscosity This is a value measured using a glass capillary viscometer according to JIS K 2283: 2000.
(2) Viscosity index Measured according to JIS K 2283: 2000.
(3) Hot tube test In a glass tube having an inner diameter of 2 mm maintained at 310 ° C, the lubricating oil composition was continuously supplied at 0.3 ml / hour and air at 10 ml / minute for 16 hours. The lacquer adhering in the glass tube was compared with the color sample, and a score of 11 levels was given, with 10 points for transparent and 0 points for black. The higher the score, the better the high temperature cleanability. This test was conducted based on JPI-5S-55-99.
(4) Base number The test oil after the hot tube test was collected, and the base number (base number after the test) was measured by the hydrochloric acid method based on JISK2501: 2003. Moreover, the base number before the test was also measured.
(5) Solubility Evaluation In each Example and Comparative Example, the solubility when the additive composition or the comparative additive was dissolved by heating in a base oil at 80 ° C. and then returned to room temperature (25 ° C.). Was evaluated by visual observation. The case where no unmelted residue was evaluated was “A”, and the case where undissolved residue was generated was evaluated as “B”.
(6) Thermal property evaluation The degree of contamination of peripheral components such as filters by each additive composition and comparative additive was simply evaluated by TG-DTA. Specifically, “TG / DTA 6200” manufactured by SII is used as a thermal analysis apparatus, and after the additive composition or comparative additive is set in an aluminum pan, the temperature is 50 ° C. under a stream of nitrogen gas of 200 mL / min. From 600 ° C. to 600 ° C., the temperature was increased at a rate of 10 ° C./min, and the nonvolatile residual rate (%) at 500 ° C. was determined from the DTA curve.
It shows that the lower the non-volatile residual ratio, the higher the combustibility of the additive composition or the comparative additive and the less the contamination.

(Synthesis Example 1)
A 1000 ml four-necked flask was charged with 21.4 g (0.510 mol) of lithium hydroxide and 100 ml of distilled water, and 2,2,4,8,10,10-hexamethylundecane- represented by the following structural formula 142.2 g of 5-carboxylic acid (carbon number of branched alkyl group: 17, branching degree: 5, 0.500 mol, equivalent ratio to metal: 0.98) was added, and the mixture was reacted for 6 hours with heating under reflux. Thereafter, water was distilled off under reduced pressure. Furthermore, it dried under reduced pressure at 120 ° C. with a vacuum pump to obtain 144.2 g (yield 98%) of the desired product (additive composition (A)).

(Synthesis Example 2)
To a 1000 ml four-necked flask, 27.0 g (0.500 mol) of sodium methoxide was charged, 300 ml of methanol was added on an ice water bath, and the mixture was stirred at room temperature for 1 hour. To this mixed solution, 142.2 g of 2-heptylundecanoic acid represented by the following structural formula (carbon number of branched alkyl group: 17, degree of branching: 1,0.500 mol, equivalent ratio to metal: 1) was dropped. And stirred at room temperature for 5 hours. Next, after distilling off methanol under reduced pressure, it was further dried at 120 ° C. under reduced pressure with a vacuum pump for 5 hours to obtain 154.0 g (yield 100%) of the desired product (additive composition (B)). Obtained.

(Synthesis Example 3)
To a 1000 ml four-necked flask, 27.0 g (0.500 mol) of sodium methoxide was charged, and 100 ml of methanol was added and dissolved. This mixed solution was cooled on an ice-water bath, and a solution of 142.2 g (0.500 mol, equivalent ratio to metal: 1) of 2,2,4,8,10,10-hexamethylundecane-5-carboxylic acid in 90 ml of methanol. Was added dropwise and stirred at room temperature for 0.5 hour. Next, after distilling off methanol under reduced pressure, the residue was further dried at 90 ° C. for 2 hours under reduced pressure with a vacuum pump to obtain 152.5 g (yield 99%) of the desired product (additive composition (C)). Obtained.

(Synthesis Example 4)
To a 1000 ml four-necked flask, 16.2 g (0.300 mol) of sodium methoxide was charged, and 100 ml of methanol was added and dissolved. At room temperature, 85.4 g (0.300 mol, equivalent ratio with respect to metal: 1) of a branched octadecanoic acid mixture (Emery871, manufactured by Henkel, carbon number of branched alkyl group: 17, degree of branching 1.3) was added to this mixed solution. Methanol 200 ml solution was added dropwise and stirred at room temperature for 1 hour. Subsequently, after distilling off methanol under reduced pressure, the product was further dried at 120 ° C. under reduced pressure with a vacuum pump for 2 hours to obtain 91.6 g of the desired product (additive composition (D)) (yield 99%). Got.

(Synthesis Example 5)
A 1000 ml four-necked flask was charged with 14.6 g (0.250 mol) of magnesium hydroxide and 250 ml of distilled water, and 142.2 g of 2,2,4,8,10,10-hexamethylundecane-5-carboxylic acid ( 0.500 mol, equivalent ratio to metal: 1) was added, and the mixture was reacted for 20 hours under reflux with heating. After allowing to cool, 300 ml of hexane was added, insoluble matters were removed by filtration, and the filtrate was concentrated. Furthermore, it dried under reduced pressure at 120 ° C. with a vacuum pump to obtain 147.4 g (yield 100%) of the desired product (additive composition (E)).

[Examples 1 to 5]
The additive compositions (A) to (E) and other components obtained in the above Synthesis Examples 1 to 5 and other components were added to the base oil with the formulation shown in Table 1 and stirred, and the lubrication of Examples 1 to 5 was performed. Each oil composition was prepared.
About the obtained lubricating oil composition, the hot tube test and the base number measurement were implemented, and the performance of the lubricating oil composition of each Example was evaluated. Furthermore, the solubility and thermal characteristics of the additive compositions (A) to (E) used in each example were also evaluated. The results are shown in Table 2.

[Comparative Example 1]
Without using the additive compositions (A) to (E), a lubricating oil composition was prepared with the formulation shown in Table 1 and evaluated in the same manner as in the above examples except for solubility and thermal characteristics. The results are shown in Table 2.

[Comparative Examples 2 to 6]
Instead of the additive composition, the following comparative additives (F) to (J) were used to prepare a lubricating oil composition with the formulation shown in Table 1, and the lubricating oil composition was the same as in Examples 1 to 5 Evaluation was performed. In addition, the solubility and thermal properties of the comparative additives (F) to (J) used in each comparative example were also evaluated. The results are shown in Table 2.
Comparative additive (F): Calcium phenate Comparative additive (G): Stearic acid Comparative additive (H): Lithium stearate Comparative additive (I): Sodium stearate Comparative additive (J): Magnesium stearate

Each component other than the additive composition and comparative additive in Table 1 is as follows.
Base oil: Mineral oil (hydrorefined mineral oil of 100 neutral fraction, 40 ° C. kinematic viscosity = 21.0 mm ² / s, 100 ° C. kinematic viscosity = 4.5 mm ² / s, viscosity index = 127, sulfur content = 5 mass (below ppm)
Non-boronated succinimide derivative: polybutenyl succinic acid bisimide, number average molecular weight of polybutenyl group: 1300, base number (perchloric acid method): 11.9 mgKOH / g, nitrogen content: 1.0 mass%
Boronated succinimide derivative: polybutenyl succinic acid bisimide borated compound, polybutenyl group number average molecular weight: 950, base number (perchloric acid method): 25 mgKOH / g, nitrogen content: 1.2% by mass, boron Content: 1.3% by mass
Antioxidant: Mixture of amine antioxidant and phenolic antioxidant Other additives: Alkylbenzotriazole (metal deactivator), silicone antifoaming agent, olefin copolymer (viscosity index improver), And anti-wear agents (thiadiazoles)

As shown in Table 2, in Examples 1-5, the solubility with respect to the base oil and the high temperature cleanability could be increased. Furthermore, as is apparent from the results of TG-DTA, non-volatile residue during combustion is reduced, and contamination of peripheral parts such as filter clogging is easily prevented.
On the other hand, Comparative Examples 1 and 3 did not contain a metallic detergent, so that both the base number before the test and the high-temperature cleanability were insufficient. In Comparative Example 2, instead of the long-chain branched carboxylic acid, a metal-based detergent made of phenate was used so that the metal content was equal to or higher than that of this example, but the temperature was higher than that of this example. The cleanliness is low. Further, as is clear from the results of TG-DTA, non-volatile residue at the time of combustion increases, and contamination of peripheral parts such as filter clogging is likely to occur.
Furthermore, in Comparative Examples 4-6, since the alkyl group which saturated aliphatic monocarboxylic acid has was linear, it can understand that the solubility with respect to base oil is inadequate, and it is difficult to use practically.

Claims (11)

  An additive composition comprising a metal salt of a saturated aliphatic monocarboxylic acid having a branched alkyl group having 8 to 32 carbon atoms.   The additive composition according to claim 1, wherein the degree of branching of the saturated aliphatic monocarboxylic acid is 1 or more. The additive composition according to claim 1 or 2, wherein the saturated aliphatic monocarboxylic acid is a compound represented by the following formula (1).

(In formula (1), n is 0 or 1, R ¹ is a hydrogen atom, or a linear or branched alkyl group having 1 to 18 carbon atoms, R ² is a hydrogen atom or a methyl group, and R ³ is a linear chain. Or a branched alkyl group having 1 to 18 carbon atoms, provided that when R ¹ is a hydrogen atom, at least R ² is a methyl group or R ³ is a branched alkyl group. The additive composition according to any one of claims 1 to 3, wherein the saturated aliphatic monocarboxylic acid is a compound represented by the following formula (2).

(In Formula (2), R ^{11 to} R ¹³ and R ^{15 to} R ¹⁷ are each independently a hydrogen atom or a methyl group, and R ¹⁴ and R ¹⁸ are each independently a hydrogen atom, a straight-chain or branched group, (It is a C1-C14 alkyl group.)   The additive composition according to any one of claims 1 to 4, wherein the metal is at least one selected from the group consisting of lithium, sodium, potassium, beryllium, magnesium, and calcium.   The additive composition according to any one of claims 1 to 5, wherein the metal is at least one selected from the group consisting of sodium and magnesium.   A lubricating oil composition comprising a base oil and the additive composition according to any one of claims 1 to 6.   The lubricating oil composition according to claim 7, wherein the metal content derived from the additive composition is 5 to 1000 ppm by mass based on the total amount of the lubricating oil composition.   The lubricating oil composition according to claim 7 or 8, further comprising a succinimide derivative.   The lubricating oil composition according to claim 9, wherein the succinimide derivative has an alkyl group having a number average molecular weight of 300 to 3000 or an alkenyl group having a number average molecular weight of 300 to 3000.   A saturated aliphatic monocarboxylic acid having a branched alkyl group having 8 to 32 carbon atoms and a metal compound are mixed and reacted to obtain an additive composition containing a metal salt of a saturated aliphatic monocarboxylic acid. The manufacturing method of an additive composition.