WO2021149323A1

WO2021149323A1 - Lubricating oil composition, and lubricating oil composition for internal combustion engines

Info

Publication number: WO2021149323A1
Application number: PCT/JP2020/041275
Authority: WO
Inventors: 周次郎大槻; 宏尚松枝
Original assignee: Dic株式会社
Priority date: 2020-01-20
Filing date: 2020-11-05
Publication date: 2021-07-29

Abstract

With respect to this lubricating oil composition, a glycerol dioleate ester and a glycerol trioleate ester exhibit extremely high solubility in a synthetic oil and are able to be added without any limitation, while being capable of forming a lubricant oil film on a metal surface and preventing metals from coming close to each other. Consequently, this lubricating oil composition has excellent lubrication performance and enables improvement of fuel efficiency by lowering the coefficient of friction without deteriorating the other characteristics of existing internal combustion engine oils. In addition, this lubricating oil composition is able to prevent wear of a friction surface, thereby having an effect of improving the lubrication performance and the like.　A lubricating oil composition which is characterized by containing a base oil and one or more fatty acids selected at least from among glycerol difatty acid esters and glycerol trifatty acid esters, and which is also characterized in that the fatty acids are contained in the lubricating oil composition in an amount of from 0.1 to 10.0% by mass.

Description

Lubricating oil composition and lubricating oil composition for internal combustion engine

The present invention relates to a lubricating oil composition containing a glycerin difatty acid ester and a glycerin trifatty acid ester, and a lubricating oil composition for an internal combustion engine.

Reducing fuel efficiency of automobiles has become a very important issue from the viewpoint of resource protection and environmental protection, and has been carried out by reducing the weight of the vehicle body, improving the combustion of the engine, and reducing the friction of the engine and drive train. Among them, engine friction has been reduced by improving the valve train mechanism, reducing the surface roughness of sliding members, and using fuel-efficient engine oil. The mainstream of fuel-efficient engine oil is a combination of low viscosity engine oil and addition of a friction reducing agent, which is intended to reduce friction loss under fluid lubrication conditions such as pistons and bearings. It is expected that the viscosity of engine oil will be further reduced in the future, and it may spread to other countries where the viscosity has not been reduced so far.

Fuel efficiency is reduced by adding a friction reducing agent because organic molybdenum compounds containing sulfur such as dialkyl dithiocarbamate molybdenum (MoDTC) or dialkyl dithiophosphate molybdenum (MoDTP) have an excellent friction reducing effect. Widely used as a lubricating oil such as oil.

However, there is a limit to the friction reduction effect simply by increasing the blending amount of the organic molybdenum compound, and there are problems such as precipitation of the organic molybdenum compound and generation of deposits due to deteriorated substances due to the large blending amount.

Therefore, a lubricating oil composition or the like in which an organic molybdenum compound and an ashless friction modifier (for example, a polyhydric alcohol partial fatty acid ester) are used in combination is being studied. As the polyhydric alcohol partial fatty acid ester, glycerin monofatty acid ester is widely used at present, and it has been reported that friction of lubricating oil can be reduced (Patent Documents 1 to 3).

Japanese Unexamined Patent Publication No. 05-279686 Japanese Unexamined Patent Publication No. 08-07890 Japanese Unexamined Patent Publication No. 2005-082709

As mentioned above, the base oil of internal combustion engine oil is becoming more and more low in viscosity in order to reduce fuel consumption, and at the same time, it is necessary to maintain and improve heat resistance, which is one of the very important required characteristics. For this reason, there has been a shift to synthetic oils (poly-α-olefins (PAOs), ethylene-α-olefins, GTL base oils) that have both low viscosity and high heat resistance. On the other hand, the glycerin monofatty acid ester has a new problem that it is difficult to use because of its low solubility in synthetic oils due to its molecular polarity and low affinity with synthetic oils.

An object of the present invention is to provide a lubricating oil composition having excellent frictional properties, particularly a lubricating oil composition for an internal combustion engine, which is suitable for use as a lubricating oil for an internal combustion engine.

As a result of diligent studies in view of the above circumstances, the present inventors contain at least one or more glycerin fatty acid esters selected from glycerin difatty acid ester or glycerin tri-fatty acid ester, and lubricate the glycerin fatty acid ester. The lubricating oil composition for an internal combustion engine, which is characterized by containing 0.1 to 10.0% by mass in the oil composition, is under conditions in a wide temperature range and pressure range, and under conditions where an external force such as a shearing force is applied. Also, they have found that low friction performance and lubrication performance can be maintained for a long period of time, and have completed the present invention.

That is, the present invention
1. 1. The base oil and at least one or more fatty acid esters selected from glycerin di fatty acid ester or glycerin tri fatty acid ester are contained, and the fatty acid ester is contained in the lubricating oil composition in an amount of 0.1 to 10.0% by mass. A characteristic lubricating oil composition.
2. The lubricating oil composition according to claim 1, wherein the glycerin difatty acid ester or the glycerin trifatty acid ester is selected from at least one of the following formulas (1) and (2).

(However, R ¹ to R ⁵ are saturated or unsaturated alkyl groups having 1 to 30 carbon atoms, and the alkyl groups may be linear or branched.)
3. 3. A lubricating oil composition, wherein the base oil contains a hydrocarbon-based synthetic oil.
4. The lubricating oil, wherein the hydrocarbon-based synthetic oil comprises PAO2, PAO4, PAO6, PAO8, PAO9, PAO10, PAO40, PAO100, ethylene-α-olefin, GTL base oil, or a mixture thereof. Composition.
5. The above-mentioned lubricating oil composition for an internal combustion engine.
6. The internal combustion engine lubricating oil further comprises 0.01 to 1% by weight of at least one or more additives selected from molybdenum dialkyldithiocarbamate or molybdenum dialkyldithiophosphate in the lubricating oil composition for internal combustion engine. Regarding the composition.

Lubricating oil compositions and lubricating oil compositions for internal combustion engines containing the base oil of the present invention and at least one or more fatty acid esters selected from at least glycerin di fatty acid ester or glycerin tri fatty acid ester have a wide temperature range and pressure range. It is possible to improve low friction performance and lubrication performance for a long period of time even under conditions or conditions where an external force such as shearing force is applied. Therefore, in the present invention, it is possible to provide a beneficial lubricating oil composition and a lubricating oil composition for an internal combustion engine. It is speculated that this is because glycerin di fatty acid ester and glycerin tri fatty acid ester are adsorbed on the metal surface, and then they form a lubricating oil film on the metal surface to prevent the metals from approaching each other, resulting in a significant decrease in the coefficient of friction. There is.

The present invention is a lubricating oil composition and a lubricating oil composition for an internal combustion engine.

The lubricating oil composition and the lubricating oil composition for an internal combustion engine of the present invention are composed of a base oil and a specific glycerin fatty acid ester.

The glycerin fatty acid ester of the present invention is used as a lubricating oil composition by blending with a base oil, or as a grease composition by blending with a base oil and a thickener.

<Base oil>
The lubricating oil composition and the lubricating oil composition for an internal combustion engine of the present invention include a base oil. The base oil may be a mineral oil or a synthetic oil.

The mineral oil includes atmospheric distillation oil obtained by atmospheric distillation of paraffinic and naphthenic crude oils, distillate oil obtained by further vacuum distillation of the residual oil obtained by atmospheric distillation, and the distillate. Mineral oil refined by performing one or more treatments such as solvent removal, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrorefining, etc., for example, light neutral oil, medium grade. Examples thereof include neutral oil, heavy neutral oil, bright stock, and mineral oil obtained by isomerizing a wax (GTL wax) produced by the Fisher-Tropsch method or the like.

The mineral oil may be classified into any of groups 1, 2 and 3 in the base oil category of API (American Petroleum Institute), but sludge formation can be further suppressed, and viscosity characteristics and oxidation can be achieved. From the viewpoint of obtaining stability against deterioration and the like, hydrorefined oils classified into groups 2 and 3 are preferable.

In the present invention, the base oil may contain a hydrocarbon-based synthetic oil, and may contain a poly-α-olefin, PAO2, PAO4, PAO6, PAO8, PAO9, PAO10, PAO40, PAO100, ethylene-α-olefin, GTL (Gas). to liquids) It consists of a base oil or a mixture thereof. Further, as the synthetic oil, for example, poly-α-olefins such as polybutene, ethylene-α-olefin copolymer, α-olefin homopolymer or copolymer, polyol ester, dibasic acid ester, phosphoric acid ester and the like. Examples thereof include various ester oils, various ethers such as polyphenyl ethers, polyglycols, alkylbenzenes, and alkylnaphthalene.

As the base oil, the above-mentioned mineral oil and synthetic oil may be used alone or in combination of a plurality of types, or may be used in combination with one or more of the above-mentioned synthetic oils. As the base oil used in the lubricating oil composition of the present invention and the lubricating oil composition for internal combustion engine oil, mineral oils and hydrocarbon-based synthetic oils are preferable, paraffin-based refined mineral oils, poly-α-olefins, and GTL. Base oils are more preferred.

Regarding the viscosity of the base oil, the lower the viscosity, the less friction loss can be expected, especially under fluid lubrication conditions such as pistons and bearings, but there are problems such as oil film breakage on the friction surface and seizure and wear of the metal surface due to metal contact. From the viewpoint of obtaining an appropriate viscosity, the kinematic viscosity at 100 ° C. is preferably 1 mm2 / s or more, more preferably 1.5 mm2 / s or more, still more preferably 2 mm2 / s or more. The upper limit is preferably 50 mm2 / s or less, more preferably 40 mm2 / s or less, and even more preferably 30 mm2 / s or less. In the present specification, the kinematic viscosity is a value measured using a glass capillary viscometer in accordance with JIS K 2283: 2000. When the kinematic viscosity and the viscosity index of the base oil are within the above ranges, the composition becomes more suitable as a lubricating oil composition for a transmission, and seizure resistance and copper corrosion resistance are improved.

The content of the base oil based on the total amount of the composition shall be appropriate, and from the viewpoint of improving seizure resistance and copper corrosion resistance, it is usually 50% by mass or more, preferably 60% by mass or more, and more preferably 65. By mass or more, more preferably 70% by mass or more. The upper limit is preferably 97% by mass or less, more preferably 95% by mass or less, and further preferably 93% by mass or less.

The lubricating oil composition and the lubricating oil composition for an internal combustion engine of the present invention contain a specific glycerin fatty acid ester.

<Glycerin fatty acid ester>
The glycerin fatty acid ester used in the present invention preferably has a di-form or a tri-form fatty acid moiety, and the glycerin fatty acid ester has extremely high solubility even when poly-α-olefin is the main component of the base oil. , It is possible to add a large amount. Therefore, the design range of the lubricating oil composition and the lubricating oil composition for an internal combustion engine is widened, and various designs are possible. Further, a thick lubricating oil film can be formed on the metal surface, and the metals can be prevented from coming close to each other. As a result, since the lubrication performance is excellent, not only the friction coefficient is lowered and the fuel efficiency is improved, but also the wear of the friction surface can be prevented.

Low friction performance can be obtained by containing one or more kinds of fatty acid esters selected from glycerin di fatty acid ester or glycerin tri fatty acid ester and containing 0.1 to 10.0% by mass in the lubricating oil composition. .. Further, 0.1 to 5.0% by mass is a suitable content. Equations (1) and (2).

However, R ¹ to R ⁵ are saturated or unsaturated alkyl groups having 1 to 30 carbon atoms, and the alkyl groups may be linear or branched.

The alkyl group preferably has 8 to 22 carbon atoms, but is 10 to 10 to 22 in that it has an easily available fatty acid carbon number and is excellent in base oil solubility, which is commercially available in the glycerin fatty acid ester market. 20 is more preferred.

Examples of the glycerin difatty acid ester include glycerin dioctylate, glycerin dinonanoic acid ester, glycerin didecanoic acid ester, glycerin didodecanoic acid ester, glycerin ditetradecanoic acid ester, glycerin dipentadecanoic acid ester, glycerin dihexadecanoic acid ester, and glycerin di. -9-Hexadecenoic acid ester, glycerin diheptadecanoic acid ester, glycerin dioctadecanoic acid ester, glycerin dioleic acid ester, glycerin divacenoic acid ester, glycerin dilinoleic acid ester, glycerinji-9,12,15-linolenic acid ester , Glycerindi-6,9,12-linolenic acid ester, glycerin dieleostearic acid ester, glycerin dieicosanoic acid ester, glycerinji-8,11-eicosadienoic acid ester, glycerin dimedic acid ester, glycerin diarachidonic acid ester , Glycerin didokosanoic acid ester and the like. Of these, glycerin dioleic acid ester is preferable.

Examples of the glycerin trifatty acid ester include glycerin trioctylate, glycerin trinonanoic acid ester, glycerin tridecanoic acid ester, glycerin tridodecanoic acid ester, glycerin tritetradecanoic acid ester, glycerin tripentadecanoic acid ester, glycerin trihexadecanoic acid ester, and glycerin. Tri-9-hexadecenoic acid ester, glycerin triheptadecanoic acid ester, glycerin trioctadecanoic acid ester, glycerin trioleic acid ester, glycerin trivacene acid ester, glycerin trilinoleic acid ester, glycerin tri-9,12,15-linolenic acid Estel, glycerin tri-6,9,12-linolenic acid ester, glycerin trieleostearic acid ester, glycerin trieicosanoic acid ester, glycerin tri-8,11-eicosadienoic acid ester, glycerin trimide acid ester, glycerin triarachidonic acid Examples thereof include esters and glycerin tridocosanoic acid esters. Of these, glycerin trioleic acid ester is preferable.

The lubricating oil composition and the lubricating oil composition for an internal combustion engine of the present invention can be further adjusted by adding various additives.

The lubricating oil composition of the present invention may contain an organic molybdenum compound. The organic molybdenum compound contained in the lubricating oil composition may be of a single type or two or more types. The organic molybdenum compound is not particularly limited as long as it can be used in the lubricating oil industry such as molybdenum dialkyldithiocarbamate (MoDTC), molybdenum dialkyldithiophosphate (MoDTP), and molybdenum amine. Above all, by adding one or more kinds of additives selected from molybdenum dialkyldithiocarbamate or molybdenum dialkyldithiophosphate, the low friction performance can be further improved as a lubricating oil composition for an internal combustion engine.

By adding an organic molybdenum compound to the lubricating oil composition of the present invention, it can be appropriately set in consideration of the friction reducing effect, sludge suppression, and corrosion prevention.

In the case of the lubricating oil composition for internal combustion engine oil, the amount of molybdenum metal is preferably 50 to 2000 mass ppm, preferably 70 to 1500 mass ppm, based on the total amount of the lubricating oil composition for internal combustion engine oil. Is more preferable, and 80 to 1000 mass ppm is further preferable.

When the glycerin fatty acid esters of the present invention are used in grease, a thickener can be added.

Examples of the thickener include soap-based or complex soap-based thickeners, organic non-soap-based thickeners, and inorganic non-soap-based thickeners. The consistency of the grease in which the lubricating additive composition of the present invention is used varies depending on the application in which the grease is used and is not particularly limited, but is usually about 100 to 500, and the content of the thickener is 100 parts by mass of the base oil. On the other hand, it is usually about 5 to 20 parts by mass.

<Other additives>
As other additives, for example, an oil-based agent, a metal-based cleaning agent, an ashless dispersant, an antioxidant, an abrasion resistant agent, an extreme pressure agent, and a rust preventive, as long as the object of the present invention is not impaired. , Viscosity index improver, metal inactivating agent, defoaming agent, solid lubricant, flow point lowering agent, corrosion inhibitor, anti-emulsifier, solid lubricant, etc. can be added as appropriate, and any one or two More than seeds may be added.

<Oil-based agent>
Examples of the oily agent include aliphatic saturated and unsaturated monocarboxylic acids such as stearic acid and oleic acid; polymerized fatty acids such as dimer acid and hydrogenated dimer acid, hydroxy fatty acids such as ricinoleic acid and 12-hydroxystearic acid, and lauryl. Fatty acid saturated and unsaturated monoalcohols such as alcohol and oleic alcohol, aliphatic saturated and unsaturated monoamines such as stearic acid and oleylamine, aliphatic saturated and unsaturated monocarboxylic acid amides such as laurate amide and oleic acid amide, pigs Examples include unsaturated animal and vegetable fats and oils such as fat (lard), beef fat, fish oil, palm oil, soybean oil, rapeseed oil, and coconut oil. One of these may be used alone, or two or more thereof may be used in combination. The content of the oily agent is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, and preferably 10% by weight or less, more preferably, based on the total amount of the lubricating oil composition described later. Is 5% by weight or less.

<Metal-based cleaning agent>
As a metal-based cleaning agent, one having a TBN (total base number (Total Base Number) based on ASTM D2896) of 20 to 600 mgKOH / g is known, and the amount to be added is appropriately set according to the TBN value. .. Metal-based cleaning agents are usually available on the market in a state of being diluted with a light lubricating oil base oil or the like. In the lubricating oil composition of the present invention, the TBN of the metal-based cleaning agent is preferably 50 to 500 mgKOH / g, and more preferably 100 to 450 mgKOH / g. Further, the metal-based cleaning agent usually raises TBN by blending a carbonate of an alkaline earth metal, but a part of the carbonate may be a borate.

The content of the metal-based cleaning agent is preferably 0.1 to 10% by mass, more preferably 0.5 to 8% by mass, based on the total amount of the lubricating oil composition, from the viewpoint of sufficiently exerting the friction reducing effect. It is more preferably ~ 5% by mass.

<Ashes-free dispersant>
Examples of the ashless dispersant include a succinic anhydride-type dispersant obtained by a condensation reaction between alkenyl succinic anhydride and a polyamine compound, and a succinic acid ester-type dispersant obtained by a condensation reaction between alkenyl succinic anhydride and a polyol compound. Examples thereof include a succinic anhydride type dispersant obtained by a condensation reaction of alkenyl succinic anhydride and alkanolamine, and a Mannig basic dispersant obtained by condensing alkylphenol and polyamine with formaldehyde.

The content of the ashless dispersant component is preferably 0.5 to 10% by mass, preferably 1 to 8% by mass, based on the total amount of the lubricating oil composition, from the viewpoint of sufficiently exerting the effect of adding the dispersant while maintaining fluidity. % Is more preferable, and 2 to 6% by mass is most preferable.

<Antioxidant>
Examples of the antioxidant include an aromatic amine-based antioxidant, a phenol-based antioxidant, a sub-phosphate-based antioxidant, and a thioether-based antioxidant. Above all, it is preferable to contain a phenolic antioxidant because it has high antioxidant performance and can maintain the effect of improving lubricity for a long period of time when combined with an organic molybdenum compound.

Examples of the sulfur-based antioxidant include thiodipropionic acid ester, thiobis (phenol) compound, polyhydric alcohol ester of alkyl thiopropionic acid, 2-mercaptobenzimidazole, dilauryl sulfide, amylthioglycolate, olefin sulfide, and dialkyl. Examples thereof include polysulfide, dialkyl disulfide, and dialkyl monosulfide.

The content of the antioxidant is preferably 0.01 to 1% by mass, preferably 0.15 to 0% by mass, based on the total amount of the lubricating oil composition, from the viewpoint of the antioxidant effect and the suppression of decomposition of other additives. It is more preferably 95% by mass, and most preferably 0.2 to 0.9% by mass.

In the lubricating oil for internal combustion engines and the like, an amine-based antioxidant may be used as the antioxidant, but in the lubricating oil composition of the present invention, the organic molybdenum compound component is composed of the amine-based antioxidant component. It is preferable not to contain an amine-based antioxidant because it reduces the friction reducing effect of the above, and even if it is contained, it is preferably 0.3% by mass or less based on the total amount of the lubricating oil composition. , 0.1% by mass or less, more preferably 0.05% by mass or less.

<Abrasion inhibitor>
Examples of the anti-wear agent include zinc dithiophosphate, alkyl phosphate ester, aryl phosphate ester, alkyl thiophosphate ester and the like. Since the lubricating oil composition of the present invention has a large anti-wear effect and also has an effect of improving the lubricity of the organic molybdenum compound component, it contains zinc dithiophosphate represented by the following formula (3) as an anti-wear component. It is preferable to do so.

(In the formula, R ⁶ to R ⁹ represent alkyl groups having 3 to 14 carbon atoms.)

In the general formula (3), R ⁶ to R ⁹ represent an alkyl group having 3 to 14 carbon atoms. The alkyl group having 3 to 14 carbon atoms includes a linear primary alkyl such as a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, a dodecyl group, a tridecyl group, and a tetradecyl group. Group: Isobutyl group, isopentyl group, isohexyl group, isoheptyl group, isooctyl group, isononyl group, isodecyl group, isododecyl group, isotridecyl group, isotetradecyl group, 2-methylpentyl group, 2-ethylhexyl group, 2-propylheptyl group , 2-Butyl octyl group, 2-Pentyl nonyl group, 3,7-Dimethyl octyl group and other branched primary alkyl groups; isopropyl group, secondary butyl group, secondary pentyl group, secondary hexyl group, secondary heptyl group. Secondary alkyl group of secondary octyl group, secondary nonyl group, secondary decyl group, secondary dodecyl group, secondary tridecyl group, secondary tetradecyl group, 1,3-dimethylbutyl group; t-butyl group, t -A tertiary alkyl group such as a pentyl group can be mentioned.

Since R ⁶ to R ⁹ improve the lubricity of the organic molybdenum compound component, a secondary alkyl group having 4 to 14 carbon atoms is preferable, a secondary alkyl group having 4 to 10 carbon atoms is more preferable, and a secondary alkyl group having 4 to 10 carbon atoms is more preferable. The secondary alkyl group of ~ 8 is more preferable. R ⁶ to R ⁹ may be the same group or a combination of different groups.

Examples of the phosphorus-based wear resistant agent include organic phosphine, organic phosphine oxide, organic phosphinite, organic phosphonite, organic phosphinate, organic phosphite, organic phosphonate, organic phosphate, and organic phosphoramidate. These also have a function as a phosphorus-based antioxidant.

The content of the anti-wear component is preferably 0.001 to 3% by mass, preferably 0.005 to 2% by mass, in terms of the amount of phosphorus derived from the anti-wear component, based on the total amount of the lubricating oil composition. It is more preferable, and most preferably 0.01 to 1% by mass.

<Extreme pressure agent>
Examples of the sulfur-based extreme pressure agent include sulfide fats and oils, sulfide esters, polysulfides, sulfide olefins, sulfide fatty acids, sulfide ore oils, sulfides of polyolefins, 1,3,4-thiathiol derivatives, thiuram disulfides, dithiocarbamic acid esters and the like. Be done. Examples of the thiophosphate-based extreme pressure agent include organic trithiophosphate and organic thiophosphate.

Examples of the sulfide fat and oil include sulfides of unsaturated animal and vegetable fats and oils such as pork fat (lard), beef tallow, fish oil, palm oil, soybean oil, rapeseed oil, and coconut oil. Specific examples of the sulfide oil and fat include lard sulfide, rapeseed sulfide oil, castor oil sulfide, soybean sulfide oil, fish sulfide oil, and whale sulfide oil.

Examples of the polysulfide include a compound having a structure of the formula (4), which is classified into a primary type polysulfide, a secondary type polysulfide, and a tertiary type polysulfide based on the structure. May be used.

R ^10- Sx-R ¹¹ (4)
(In the formula, R ¹⁰ and R ¹¹ independently represent a linear or branched alkyl group or alkenyl group having 2 to 24 carbon atoms, respectively, and x represents an integer of 1 to 8.)

Typical methods for producing polysulfide are a method of sulfurizing an olefin and a method of sulfur-crosslinking a mercaptan, but the polysulfide of the present invention may be produced by any method.

Examples of the polysulfide obtained by the method of sulfurizing an olefin include a sulfide of a hydrocarbon having at least one ethylene-based unsaturated bond, and is also called a sulfide olefin. The monoolefins are not particularly limited, and are, for example, isobutylene, 2-methyl-2-pentene, 2-methyl-2-butene, 2-methyl-1-butene, diisobutylene, triisobutylene, and tripropylene. , 1-hexene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and other chain alkenes, as well as cyclopentene, cyclohexene and other cyclic alkenes. These can also be used as mixtures. Examples of diene having 4 to 10 carbon atoms include 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 1,3-pentadiene (piperylene), cyclopentadiene, and 1,5. -Hexadiene, cyclohexadiene, 1,6-heptadiene, cycloheptadiene, 1,7-octadiene, cyclooctadiene and the like can be mentioned, and these may be used alone or in combination of two or more, and sulfides thereof. Can be mentioned.

The polysulfide obtained by the method of sulfur-crosslinking mercaptans is a sulfide obtained by reacting mercaptans with powdered sulfur and molten sulfur using a basic catalyst, such as dibutyl polysulfide, dipentyl polysulfide, dihexyl polysulfide, and dicyclohexyl polysulfide. , Diheptyl polysulfide, dioctyl polysulfide, dibenzyl polysulfide, dinonyl polysulfide, didodecyl polysulfide, diundecyl polysulfide and the like. Examples of the polysulfide include dibutyl polysulfide, dipentyl polysulfide, dihexyl polysulfide, dicyclohexyl polysulfide, diheptyl polysulfide, dioctyl polysulfide, dibenzyl polysulfide, dinonyl polysulfide, didodecyl polysulfide, and diundecyl polysulfide.

When added to the lubricating oil for internal combustion engine oil, the sulfur cross-linking length x of the polysulfide and the sulfide olefin is preferably 1 to 4 and more preferably 1 to 3 because it is necessary to maintain oxidative stability.

Examples of sulfide fatty acids include unsaturated fatty acids such as mini-strain acid, palmitere acid, sapienoic acid, oleic acid, elaidic acid, bacenoic acid, gadrainic acid, eicosenoic acid, erucic acid, nervonic acid, linoleic acid, eikosazienoic acid, docosazienoic acid, etc. Linolenic acid, pinolenic acid, eleostearic acid, meadic acid, dihomo-γ-linolenic acid, eikosatrienic acid, stearidonic acid, arachidonic acid, eikosatetraenoic acid, adrenoic acid, boseopentaenoic acid, osbondic acid, sardine acid, Examples include sulfides of unsaturated fatty acids such as tetracosapentaenoic acid, docosahexaenoic acid, heric acid, beef fatty acids and palm kernel fatty acids.

<Rust inhibitor>
Examples of the rust preventive agent include calcium oxide paraffin wax calcium salt, paraffin wax magnesium oxide salt, beef fat fatty acid alkali metal salt, alkaline earth metal salt or amine salt, alkenyl succinic acid or alkenyl succinic acid half ester (the molecular weight of the alkenyl group is Approximately 100 to 300), sorbitan monoester, pentaerythritol monoester, glycerin monoester, nonylphenolethoxylate, lanolin fatty acid ester, lanolin fatty acid calcium salt and the like. The amount of the rust preventive component blended is preferably about 0.1 to 15% by mass with respect to the lubricating oil composition within a range in which the rust preventive effect is sufficiently exhibited.

<Viscosity index improver>
Examples of the viscosity index improver include poly (C1-18) alkyl methacrylate, (C1-18) alkyl acrylate / (C1-18) alkyl methacrylate copolymer, and diethylaminoethyl methacrylate / (C1-18) alkyl methacrylate copolymer. Combined, ethylene / (C1-18) alkyl methacrylate copolymer, polyisobutylene, polyalkylstyrene, ethylene / propylene copolymer, styrene / maleic acid ester copolymer, styrene / maleic acid amide copolymer, styrene / butadiene Examples thereof include hydride copolymers and styrene / isoprene hydride copolymers. The average molecular weight is about 10,000 to 1,500,000. The blending amount of the viscosity index improver component is preferably about 0.1 to 20% by mass with respect to the lubricating oil composition.

<Metal inactivating agent>
Examples of the metal inactivating agent include N, N'-salicylidene-1,2-propanediamine, alizarin, tetraalkylthiuram disulfide, benzotriazole, benzimidazole, 2-alkyldithiobenzoimidazole, and 2-alkyldithiobenzothiazole. , 2- (N, N-dialkylthiocarbamoyl) benzothiazole, 2,5-bis (alkyldithio) -1,3,4-thiadiazole, 2,5-bis (N, N-dialkylthiocarbamoyl) -1, Examples thereof include 3,4-thiadiazole. The blending amount of the metal inactivating agent component is preferably about 0.01 to 5% by mass with respect to the lubricating oil composition.

<Defoamer>
Examples of the defoaming agent include polydimethylsilicone, trifluoropropylmethylsilicone, colloidal silica, polyalkyl acrylate, polyalkyl methacrylate, alcohol ethoxy / propoxylate, fatty acid ethoxy / propoxylate, and sorbitan partial fatty acid ester. The blending amount of the defoaming agent component is preferably about 1 to 1000 mass ppm with respect to the lubricating oil composition.

<Solid lubricant>
Examples of solid lubricants include graphite, molybdenum disulfide, polytetrafluoroethylene, fatty acid alkaline earth metal salts, mica, cadmium dichloride, cadmium diiodide, calcium fluoride, lead iodide, lead oxide, and titanium carbide. , Titanium nitride, aluminum silicate, antimony oxide, cerium fluoride, polyethylene, diamond powder, silicon nitride, boron nitride fluorocarbon, melamine isocyanurate and the like. The blending amount of the solid lubricant component is preferably about 0.005 to 2% by mass with respect to the lubricating oil composition.

Among the above other additive components, the phosphorus-containing compound is contained in the lubricating oil composition because it may poison the exhaust gas purification catalyst when the lubricating oil composition of the present invention is used as the engine oil. It is preferable to use the oil in a range in which the total phosphorus content does not exceed 1000 mass ppm and the total sulfur content does not exceed 5000 mass ppm.

The lubricating oil composition of the present invention can be used for lubrication for various purposes. For example, engine oils such as gasoline engine oils and diesel engine oils, industrial lubricating oils, turbine oils, machine oils, bearing oils, compressor oils, hydraulic oils, hydraulic oils, internal combustion engine oils, refrigerating machine oils, gear oils, automatic transmissions. Examples thereof include oil for use (ATF), oil for continuously variable stepless transmission (CVTF), transaxle fluid, metal processing oil and the like. It can also be added to various greases such as sliding bearings, rolling bearings, gears, universal joints, torque limiters, constant velocity joints for automobiles (CVJ), ball joints, wheel bearings, constant velocity gears, and transmission gears. ..

Low friction performance is a typical characteristic of the lubricating oil composition of the present invention and the lubricating oil composition for internal combustion engines. As a method for measuring the friction performance, there is a friction coefficient measuring method, and in the present invention, the measurement is performed by the SRV measurement test and the pendulum friction test.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to the scope of these Examples. Unless otherwise specified, both "part" and "%" are based on weight. Moreover, the scope of the present invention is not limited by the following examples.

(Example 1)
200 mL of glass containing 1.00 g of glycerin dioleic acid ester (Poem OL-200VM (RIKEN Vitamin Co., Ltd.)) and 99.00 g of commercially available engine oil (synthetic oil PAO (polyalphaolefin) base, Toyota genuine OW-16) Weighed in a beaker. Then, using a three-one motor with a glass anchor type stirring blade, stirring and mixing was performed at 350 rpm for 30 minutes to prepare lubricating oil 1.
The order and method of addition of the glycerin partial fatty acid ester and the base oil are not particularly limited, and the method of blending the glycerin partial fatty acid ester with the base oil or the method of adding the base oil to the glycerin partial fatty acid ester may be used.

(Examples 2 to 6)
Lubricating oils 2 to 6 were prepared in the same manner as in Example 1 based on the formulations shown in Table 1 below. Glycerin dioleic acid ester: Poem OL-200VM (RIKEN Vitamin Co., Ltd.)
Glycerin trioleic acid ester: Actor OL-1 (RIKEN Vitamin Co., Ltd.)
Commercial engine oil (synthetic oil PAO base, Toyota genuine 0W-16): TOYOTA GENUINE MOTOR OIL DASTLE SN 0W-16 SYNTHETIC Commercial engine oil (synthetic oil PAO base, Nissan genuine 0W-16): Nissan Strong Save X 0W-16
Commercial engine oil (synthetic oil PAO base, Honda genuine 0W-16): Honda Ultra Green SN 0W-16

[Comparative Examples 1 to 3]
Lubricants 7-9 were prepared using only commercially available synthetic oil-based engine oils without the addition of glycerin partial fatty acid esters.

[Comparative Example 4]
Glycerin monofatty acid ester was added to a commercially available synthetic oil-based engine oil to prepare a lubricating oil 10.

The obtained lubricating oil was subjected to various tests by the following methods, and its coefficient of friction was measured. The evaluation results are shown in Table 1.

[Friction coefficient measurement method]
1. 1. SRV measurement test / use tester: Vibration friction wear tester (manufactured by Optimol, model: SRV4)
・ Evaluation conditions ・ Load: 200N
・ Temperature: 80 ℃
・ Measurement time: 120 minutes ・ Amplitude: 1 mm
-Evaluation method: The average value of the friction coefficient for 100 minutes from 20 to 120 minutes is used as the friction coefficient in this test. The lower the coefficient of friction, the better the lubricity.

2. Pendulum friction test / equipment used: Pendulum type oil-based friction tester (manufactured by Shinko Engineering Co., Ltd.)
-Evaluation conditions-Test steel ball: 3/16 inch (4.76 mm)
・ Test roller pin: φ2 x 30 mm
・ Initial amplitude: 0.50 rad
-Temperature: 25 ° C, 80 ° C
・ Number of measurements: 5 times (n = 1)

As can be seen from Table 1, the lubricating oil in which glycerinji or trifatty acid ester was added to the base oil showed excellent low friction characteristics.

Claims

The base oil and at least one or more fatty acid esters selected from glycerin di fatty acid ester or glycerin tri fatty acid ester are contained, and the fatty acid ester is contained in the lubricating oil composition in an amount of 0.1 to 10.0% by mass. A characteristic lubricating oil composition.
The lubricating oil composition according to claim 1, wherein the glycerin difatty acid ester or glycerin trifatty acid ester according to claim 1 is selected from at least one of the following formulas (1) and (2).

(However, R 1 to R 5 are saturated or unsaturated alkyl groups having 1 to 30 carbon atoms, and the alkyl groups may be linear or branched.)
The lubricating oil composition according to claim 1 or 2, wherein the base oil according to claim 1 or 2 contains a hydrocarbon-based synthetic oil.
The lubrication according to claim 3, wherein the hydrocarbon-based synthetic oil according to claim 3 comprises PAO2, PAO4, PAO6, PAO8, PAO9, PAO10, PAO40, PAO100, ethylene-α-olefin or a mixture thereof. Oil composition.
The lubricating oil composition for an internal combustion engine according to any one of claims 1 to 4.
The internal organ according to claim 5, further comprising 0.01 to 1% by weight of at least one or more additives selected from molybdenum dialkyldithiocarbamate or molybdenum dialkyldithiophosphate in the lubricating oil composition for an internal combustion engine. Lubricating oil composition for engines.