JPWO2020137651A1 - Lubricating oil composition and its manufacturing method - Google Patents

Abstract

It contains a base oil, fluorene, and a lubrication regulator, wherein the lubrication regulators include hydrindan, naphthalene, 1,2,3,4, -tetrahydronaphthalene, tetrahydrodicyclopentadiene, decahydronaphthalene, cyclododecane, Lubrication, which is at least one selected from cyclododecane, dodecahydrofluorene, anthracene, phenanthracene, 9,10-dihydroanthracene, hexadecahydropyrene, and compounds in which at least one hydrogen atom thereof is substituted with a substituent. Oil composition.

Description

The present invention relates to a lubricating oil composition and a method for producing the same.

In recent years, with the increase in speed, efficiency, high pressure, and miniaturization, lubricating oils used in automobiles, industrial machines, etc. have a sufficient machine life for a long time even when used under high pressure, high speed, and high load. Excellent lubrication performance that can guarantee the above is required. In response to such demands, it has been studied to improve the lubrication characteristics of the lubricating oil composition by adding an anti-wear agent, an extreme pressure agent, a lubricity improver and the like.

For example, Patent Document 1 discloses a lubricating oil composition containing zinc dialkyldithiophosphate in order to improve wear resistance. However, zinc dialkyldithiophosphate has a problem that the thermal oxidation stability at high temperature and high pressure and the hydrolysis stability due to the mixing of water are not sufficient. In addition, since zinc dialkyldithiophosphate contains sulfur, sulfur oxides (SO _x ) that cause air pollution are generated when oxidized. There is an urgent need to develop a lubricating oil composition that has a low environmental impact.

Further, Patent Document 2 discloses a lubricant composition containing an organic molybdenum friction modifier and a surface active sulfur donor component. Molybdenum dithiocarbamate is used as an organic molybdenum friction modifier, but the friction reducing effect of molybdenum dithiocarbamate is still insufficient.

JP-A-2018-123240 Japanese Patent Application Laid-Open No. 2014-513173

The present inventors have made this in view of the above circumstances, and an object of the present invention is to provide a lubricating oil composition having sufficient wear resistance.

The present invention includes the following [1] to [10] in order to solve the above problems.
[1] A base oil, fluorene, and a lubrication adjuster are included, and the lubrication adjuster includes hydrindan, naphthalene, 1,2,3,4-tetrahydronaphthalene, tetrahydrodicyclopentadiene, decahydronaphthalene, and cyclo. Dodecatorien, cyclododecane, dodecahydrofluorene, anthracene, phenanthracene, 9,10-dihydroanthracene, hexadecahydropyrene, and at least one selected from compounds in which at least one hydrogen atom thereof is substituted with a substituent. Lubricating oil composition.
[2] The substituent of the lubrication regulator is a halogen atom, a hydroxy group, a carboxy group, an amino group, a hydrocarbon group having 1 to 20 carbon atoms, and an ether having 1 to 20 carbon atoms. A group having a bond, a group having an ester bond having 1 to 20 carbon atoms, a group having a disulfide bond having 1 to 20 carbon atoms, and a carbon number having at least one of a halogen atom, a hydroxy group, a carboxy group, and an amino group. The lubricating oil composition according to the preceding item [1], which is at least one selected from 1 to 20 groups.
[3] The group having an ether bond having 1 to 20 carbon atoms, the group having an ester bond having 1 to 20 carbon atoms, and the group having a disulfide bond having 1 to 20 carbon atoms are halogen atoms, hydroxy groups, and the like. The lubricating oil composition according to the preceding item [2], which has at least one of a carboxy group and an amino group.
[4] The lubricating oil composition according to the above items [1] to [3], wherein the total molecular weight of the substituents in the lubricating oil adjusting agent is 60% or less of the molecular weight of the lubricating oil adjusting agent.
[5] The lubricating oil composition according to any one of the above items [1] to [4], wherein the base oil is a synthetic oil.
[6] The fullerene _is a lubricating oil composition according to any one of items [1] to [5] comprising _{C 60.}
[7] The lubricating oil composition according to any one of the above items [1] to [6], wherein the lubricating oil adjusting agent is contained in an amount of 1 to 100 parts by mass with respect to 100 parts by mass of the base oil.
[8] The lubricating oil composition according to any one of the preceding items [1] to [7], which contains 0.001 to 1.000 parts by mass of the fullerene with respect to 100 parts by mass of the lubricating regulator.
[9] The method for producing a lubricating oil composition according to any one of the preceding items [1] to [8], which comprises a mixing step of mixing a base oil, a fullerene, and a lubricant adjusting agent.
[10] The method for producing a lubricating oil composition according to the preceding item [9], which further comprises a heat treatment step after the mixing step.
[11] The method for producing a lubricating oil composition according to the preceding item [10], wherein the heat treatment temperature in the heat treatment step is 100 to 250 ° C.

According to the present invention, it is possible to provide a lubricating oil composition having excellent wear resistance.

Hereinafter, an embodiment of the present invention will be described in detail. It should be noted that the present invention can be carried out by appropriately modifying the gist without changing the gist thereof.

The lubricating oil composition obtained in the present embodiment contains a base oil, a fullerene, and a lubrication regulator. The lubricant adjusting agents include hydrindan, naphthalene, 1,2,3,4, -tetrahydronaphthalene, tetrahydrodicyclopentadiene, decahydronaphthalene, cyclododecatriene, cyclododecane, dodecahydrofluorene, anthracene, phenanthracene, 9, It is at least one selected from 10-dihydroanthracene, hexadecahydropyrene, and compounds in which at least one hydrogen atom thereof is substituted with a substituent.
(Base oil)
The base oil of the lubricating oil composition according to the present embodiment is not particularly limited, and mineral oils and synthetic oils that are widely used as the base oils of ordinary lubricating oils are preferably used.

Examples of the mineral oil include paraffin-based mineral oils and naphthen-based mineral oils in which the lubricating oil fraction of crude oil is refined by appropriately combining refining methods such as solvent refining, hydrorefining, and dewaxing. Examples of the synthetic oil include synthetic hydrocarbon oils, ether oils, ester oils and the like, and more specifically, poly-α-olefin (PAO), diesters, polyalkylene glycols, polyalphaolefins, polyalkylvinyl ethers, etc. Polybutene, isoparaffin, olefin copolymer, alkylbenzene, alkylnaphthalene, diisodecyl adipate, monoester, dibasic acid ester, tribasic acid ester, polyol ester (trimethylol propane caprilate, trimethylol propane pelargonate, pentaerythritol 2-ethylhexa Noate, pentaerythritol pelargonate, etc.), dialkyldiphenyl ether, alkyldiphenyl sulfide, polyphenyl ether, silicone lubricating oil (dimethyl silicone, etc.), perfluoropolyether, and the like are preferably used.

As the base oil of the lubricating oil composition according to the present embodiment, the above-mentioned mineral oil or synthetic oil may be used alone, or two or more kinds selected from them may be mixed at an arbitrary ratio. Although it may be used, it is preferable to contain synthetic oil in consideration of heat resistance, oxidation resistance and the like, and it is more preferable to use synthetic oil. Further, it is more preferable to use a poly-α-olefin or polyol ester system which is often used in synthetic oils.
(Fullerene)
As the fullerene contained in the lubricating oil composition according to the present embodiment, the structure and the manufacturing method are not particularly limited, and various fullerenes can be used. Examples of fullerenes include C ₆₀ and C ₇₀ , which are relatively easily available, higher-order fullerenes, and mixtures thereof. _{Among fullerenes, C 60} and C ₇₀ are preferable from the viewpoint of high solubility in the base oil, _{and C 60} is more preferable from the viewpoint of less coloring in the lubricating oil. To reduce the cost, although it is also possible to use a mix fullerene having two or more fullerenes include C _60, and the content of C ₆₀ is preferably not more than 50 wt%.
(Lubrication adjuster)
The lubricant adjusting agent of the lubricating oil composition according to the present embodiment is hydrindan, naphthalene, 1,2,3,4-tetrahydronaphthalene, tetrahydrodicyclopentadiene, decahydronaphthalene, cyclododecatriene, cyclododecane, dodecahydrofluorene. , Anthracene, phenanthracene, 9,10-dihydroanthracene, hexadecahydropyrene, or at least one selected from those in which at least one hydrogen atom is replaced by a substituent described below. In addition, hydrindan, naphthalene, 1,2,3,4-tetrahydronaphthalene, tetrahydrodicyclopentadiene, decahydronaphthalene, cyclododecane, cyclododecane, dodecahydrofluorene, anthracene, phenanthracene, 9,10-dihydroanthracene. , When the hydrogen atom of hexadecahydropyrene is substituted with two or more substituents, those substituents may be the same or different.

It is presumed that the above-mentioned lubrication modifier interacts with fullerenes, and it is considered that this interaction improves the wear resistance of the lubricating oil composition. In addition, the effect of extending the lamella length of the lubricating oil composition can be expected. When the lamella length is extended, the film-forming property of the lubricating oil composition is improved, an oil film is formed with a small amount of the lubricating oil composition, and the effect of preventing leakage of the lubricating oil composition can be obtained. The longer the lamella length, the more difficult it is for the oil film to break, and the higher the seizure resistance.

When the lubricant adjusting agent has a substituent, the substituent includes a halogen atom, a hydroxy group, a carboxy group, an amino group, a hydrocarbon group having 1 to 20 carbon atoms, a group having an ether bond having 1 to 20 carbon atoms, and carbon. A group having an ester bond of 1 to 20, a group having a disulfide bond having 1 to 20 carbon atoms, a halogen atom, a hydroxy group, a carboxy group, and a group having 1 to 20 carbon atoms having at least one amino group, halogen. It has at least one of an atom, a hydroxy group, a carboxy group, and an amino group, and has at least one of a group having 1 to 20 carbon atoms having an ether bond, a halogen atom, a hydroxy group, a carboxy group, and an amino group. , A group having 1 to 20 carbon atoms having an ester bond, and a group having at least one halogen atom, a hydroxy group, a carboxy group, and an amino group and having a disulfide bond having 1 to 20 carbon atoms can be mentioned. From the viewpoint of improving the solubility of the lubrication modifier in the base oil, the group should be an alkyl group having 1 to 10 carbon atoms, a group having an ether bond having 1 to 10 carbon atoms, or a group having an ester bond having 1 to 10 carbon atoms. Is preferable.

Further, it is considered that the interaction between fullerene and the lubrication regulator becomes weaker as the ratio of the total molecular weight of the substituents to the lubrication regulator molecule increases, and the total molecular weight of the substituents is considered to be weaker than the molecular weight of the lubrication regulator molecule. The ratio is preferably 60% or less, and more preferably 50% or less.

The content of the lubricant adjusting agent in the lubricating oil composition according to the present embodiment is preferably 1 to 100 parts by mass, more preferably 2 to 50 parts by mass with respect to 100 parts by mass of the base oil. It is more preferably 5 to 25 parts by mass. If the content of the lubricant adjusting agent is within the above range, the wear resistance and seizure resistance of the lubricating oil composition are improved by interaction with fullerene, and at the same time, the ignition point, kinematic viscosity, etc. of the lubricating oil composition are affected. Changes in physical properties can be suppressed.

The fullerene content of the lubricating oil composition according to the present embodiment is preferably 0.001 to 1.000 parts by mass, and more preferably 0.001 to 0.500 parts by mass with respect to 100 parts by mass of the lubricating regulator. It is by mass, more preferably 0.005 to 0.100 parts by mass. Within the above range, the interaction between the fullerene and the lubricating regulator improves the wear resistance and seizure resistance of the lubricating oil composition, and the agglomerated particles of the fullerene are absent or few, and the agglomerated particles of the fullerene cause a friction coefficient. There is little risk of rising.
(Additive)
The lubricating oil composition according to the present embodiment may contain additives in addition to the fullerene and the lubrication adjusting agent as long as the effects of the present embodiment are not impaired. The additives to be blended in the lubricating oil composition of the present embodiment are not particularly limited. Examples of the additive include a commercially available antioxidant, a viscosity index improver, a cleaning dispersant, a pour point lowering agent, a corrosion inhibitor, a rust inhibitor, an anti-emulsifier, an antifoaming agent and the like. These additives may be used alone or in combination of two or more.

More specifically, for example, as the antioxidant, dibutylhydroxytoluene (BHT), butylhydroxyanisole (BHA), 2,6-di-tert-butyl-p-cresol (DBPC), 3-arylbenzofuran-2 Examples thereof include −one (intramolecular cyclic ester of hydroxycarboxylic acid), phenyl-α-naphthylamine, dialkyldiphenylamine, and benzotriazole. Examples of the viscosity index improver include polyalkylstyrene and hydrides of styrene-diene copolymers. Examples of the cleaning dispersant include benzylamine succinic acid derivatives, alkylphenol amines and the like. Examples of the pour point lowering agent include chlorinated paraffin-naphthalene condensate, chlorinated paraffin-phenol condensate, polyalkylstyrene type and the like. Examples of the corrosion inhibitor include zinc dithiophosphate, benzotriazole and its derivatives, 2,5-dialkyl mercapto-1,3,4-thiadiazole and the like. Examples of the rust preventive agent include carboxylic acids, sulfonates, phosphates, alcohols and the like. Examples of the anti-emulsifier include alkylbenzene sulfonate and the like. Examples of the defoaming agent include polymethylsiloxane, silicate organic fluorine compound, metal soap, fatty acid ester, phosphoric acid ester, higher alcohol, polyalkylene glycol and the like.
(Production method)
The method for producing a lubricating oil composition according to the present embodiment includes a step of mixing a base oil, a fullerene, and a lubricating adjusting agent. The mixing order is not particularly limited, and the fullerene and the lubrication regulator may be added to the base oil at the same time and mixed, or the fullerene may be mixed with the lubrication regulator and then the mixture may be added to the base oil and mixed. good. As a mixing method, a stirrer, an ultrasonic disperser, a homogenizer, a ball mill, a bead mill or the like may be used, and stirring may be performed for 1 to 48 hours at around room temperature or while heating as needed. By this mixing step, the lubricating oil composition according to the present embodiment can be obtained.

The method for producing a lubricating oil composition according to the present embodiment preferably further includes a heat treatment step after the mixing step. In order to prevent oxidation of the lubricating oil composition, it is more preferable to carry out the heat treatment step in a low oxygen atmosphere or an inert gas atmosphere. The concentration of oxygen gas in a low oxygen atmosphere is 1% volume or less, preferably 0.5% volume or less. As an example of the heat treatment step, the lubricating oil composition obtained in the mixing step is housed in a container such as airtight stainless steel, replaced with an inert gas such as nitrogen gas or argon gas, and heat-treated for 1 to 48 hours. Can be mentioned. The heat treatment temperature is preferably 100 ° C. or higher and 250 ° C. or lower, more preferably 100 ° C. or higher and 150 ° C. or lower, and further preferably 120 ° C. or higher and 150 ° C. or lower. It is presumed that this heat treatment strengthens the interaction between the fullerene and the lubricant adjusting agent, and the wear resistance and seizure resistance of the lubricating oil composition are further improved.

In the lubricating oil composition obtained by the above step, there is a possibility that an insoluble matter derived from a raw material and a solid substance such as an insoluble matter mixed in during the manufacturing process may be present. Since the coefficient of friction may increase due to the presence of these solids, a step for removing the solids may be provided after the mixing step or the heat treatment step. Examples of the removal method include a removal method by filtration, a removal method by centrifugation, and a combination of these removal methods.
(Use)
The lubricating oil composition according to the present embodiment is plastic such as industrial gear oil; hydraulic hydraulic oil; compressor oil; refrigerating machine oil; cutting oil; rolling oil, pressing oil, forging oil, drawing oil, drawing oil, punching oil and the like. It can be used for various purposes such as processing oil; metal processing oil such as heat treatment oil and discharge processing oil; slip guide surface oil; bearing oil; rust preventive oil; heat transfer oil.

Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments, and various aspects are described within the scope of the claims of the present invention. It can be transformed and changed.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.
(Synthesis of NH-C8)
To 150 g of decahydro-2-naphthol (manufactured by Tokyo Chemical Industry Co., Ltd.), 200 g of potassium iodide and 100 g of phosphoric acid are added, and after stirring at 100 ° C. for 3 hours, decahydro-2-naphthalene iodide is obtained by column chromatography. Was separated. The obtained decahydro-2-naphthalene iodide was added to 200 g of toluene, cooled to −20 ° C., 30 g of metallic magnesium was added, and the mixture was stirred for 3 hours to obtain a solution. 160 g of 1-iodooctane (manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the obtained solution, and the mixture was stirred at 25 ° C. for 12 hours, and then decahydro-2-octylnaphthalene (NH) represented by the following formula (1) was obtained by a distillation method. -C8) was obtained. The molecular weight of the obtained NH-C8 substituent is 113, which is 45% of the total molecular weight (251) of the molecule.

（ＮＰ−Ｃ５Ｃ５の合成）
２，６−ジヒドロキシナフタレン（東京化成工業（株）製）７５ｇに、ヨウ化カリウム２００ｇ、リン酸１００ｇを加え、１００℃で３時間攪拌の後、カラムクロマトグラフィー法により、２，６−ヨウ化ナフタレンを分離した。得た２，６−ヨウ化ナフタレンを、トルエン２００ｇに加え、−２０℃まで冷却して、金属マグネシウム３０ｇを添加し、３時間攪拌して溶液を得た。得た溶液に１−ヨード−３−メチルブタン（東京化成工業（株）製）７０ｇを加え、２５℃で１２時間攪拌した後、蒸留法により、下記の式（２）で示す２，６−ビス（３−メチルブチル）ナフタレン（ＮＰ−Ｃ５Ｃ５）を得た。得たＮＰ−Ｃ５Ｃ５の置換基の総分子量は１４２で、分子全体の分子量（２６８）の５３％である。

(Synthesis of NP-C5C5)
To 75 g of 2,6-dihydroxynaphthalene (manufactured by Tokyo Chemical Industry Co., Ltd.), 200 g of potassium iodide and 100 g of phosphoric acid are added, and the mixture is stirred at 100 ° C. for 3 hours and then 2,6-iolated by column chromatography. Naphthalene was separated. The obtained 2,6-naphthalene iodide was added to 200 g of toluene, cooled to −20 ° C., 30 g of metallic magnesium was added, and the mixture was stirred for 3 hours to obtain a solution. 70 g of 1-iodo-3-methylbutano (manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the obtained solution, and the mixture was stirred at 25 ° C. for 12 hours, and then 2,6-bis represented by the following formula (2) by a distillation method. (3-Methylbutyl) naphthalene (NP-C5C5) was obtained. The total molecular weight of the obtained substituents of NP-C5C5 is 142, which is 53% of the total molecular weight of the molecule (268).

（ＮＨ−Ｃ４ＰＡの合成）
デカヒドロ−２−ナフトール１５０ｇ（東京化成工業（株）製）に、ヨウ化カリウム２００ｇ、リン酸１００ｇを加え、１００℃で３時間攪拌の後、カラムクロマトグラフィー法により、２−ヨウ化デカヒドロナフタレンを分離した。得た２−ヨウ化デカヒドロナフタレンを、トルエン２００ｇに加え、−２０℃まで冷却して、金属マグネシウム３０ｇを添加し、３時間攪拌して溶液を得た。得た溶液に２，２−ジメチルプロピオン酸ヨードメチル（東京化成工業（株）製）１６０ｇを加え、２５℃で１２時間攪拌した後、蒸留法により、下記の式（３）で示す２−（２，２−ジメチルプロピオン酸メチレン）デカヒドロナフタレン（ＮＨ−Ｃ４ＰＡ）を得た。得たＮＨ−Ｃ４ＰＡの置換基の分子量は１１５で、分子全体の分子量（２５２）の４６％である。

(Synthesis of NH-C4PA)
To 150 g of decahydro-2-naphthol (manufactured by Tokyo Chemical Industry Co., Ltd.), 200 g of potassium iodide and 100 g of phosphoric acid are added, and the mixture is stirred at 100 ° C. for 3 hours and then 2-decahydronaphthalene iodide by column chromatography. Was separated. The obtained decahydronaphthalene iodide was added to 200 g of toluene, cooled to −20 ° C., 30 g of metallic magnesium was added, and the mixture was stirred for 3 hours to obtain a solution. 160 g of iodomethyl 2,2-dimethylpropionate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the obtained solution, and the mixture was stirred at 25 ° C. for 12 hours and then distilled by a distillation method to obtain 2- (2) represented by the following formula (3). , 2-Methylene 2-dimethylpropionate) decahydronaphthalene (NH-C4PA) was obtained. The molecular weight of the obtained NH-C4PA substituent is 115, which is 46% of the total molecular weight (252) of the molecule.

（ＮＴ−ＤＥＧの合成）
１，２，３，４−テトラヒドロ−１−ナフトール１５０ｇ（東京化成工業（株）製）に、ヨウ化カリウム２００ｇ、リン酸１００ｇを加え、１００℃で３時間攪拌の後、カラムクロマトグラフィー法により、１−ヨウ化−１，２，３，４−テトラヒドロナフタレンを分離した。得た１−ヨウ化−１，２，３，４−テトラヒドロナフタレンを、トルエン２００ｇに加え、−２０℃まで冷却して、金属マグネシウム３０ｇを添加し、３時間攪拌して溶液を得た。得た溶液にジエチレングリコール−２−ブロモエチルメチルエーテル（東京化成工業（株）製）１４０ｇを加え、２５℃で１２時間攪拌した後、蒸留法により、下記の式（４）で示す１−メチルトリエチレングリコール−１，２，３，４−テトラヒドロナフタレン（ＮＴ−ＤＥＧ）を得た。得たＮＴ−ＤＥＧの置換基の分子量は１４７で、分子全体の分子量（２７８）の５３％である。

(Synthesis of NT-DEG)
To 150 g of 1,2,3,4-tetrahydro-1-naphthol (manufactured by Tokyo Chemical Industry Co., Ltd.), 200 g of potassium iodide and 100 g of phosphoric acid are added, and the mixture is stirred at 100 ° C. for 3 hours and then subjected to column chromatography. , 1-Iodiation-1,2,3,4-tetrahydronaphthalene was separated. The obtained 1-iodinated-1,2,3,4-tetrahydronaphthalene was added to 200 g of toluene, cooled to −20 ° C., 30 g of metallic magnesium was added, and the mixture was stirred for 3 hours to obtain a solution. 140 g of diethylene glycol-2-bromoethylmethyl ether (manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the obtained solution, and the mixture was stirred at 25 ° C. for 12 hours, and then 1-methyltri represented by the following formula (4) by a distillation method. Ethylene glycol-1,2,3,4-tetrahydronaphthalene (NT-DEG) was obtained. The molecular weight of the obtained NT-DEG substituent is 147, which is 53% of the total molecular weight of the molecule (278).

（基油）
本発明の実施例及び比較例に使用する基油は以下となる。
合成油１：エクソンモービル社製 Ｓｐｅｃｔｒａ Ｓｙｎ（ポリ−α−オレフィン）
合成油２：日油株式会社製 ユニスターＨ−３３４Ｒ（ポリオールエステル型）
合成油３：日油株式会社製 ユニスターＭＢ−８８１（ポリオキシエチレンモノエステル型）
鉱油Ａ：出光興産株式会社製 ダイアナフレシアＰ４６
［実施例１］
（潤滑油組成物の調製）
基油として合成油１ １００ｇに、フラーレン（フロンティアカーボン（株）製ｎａｎｏｍ（登録商標） ｍｉｘ ＳＴ Ｃ_６０：６０質量％、Ｃ_７０：２５質量％、残部が他高次フラーレンの混合物である）０．００５ｇ、潤滑調整剤ＮＨ−Ｃ８ ２０ｇを添加して、室温でスターラーを用いて３６時間撹拌したのち、０．１μｍメッシュのメンブランフィルターを通すことで濾過して潤滑油組成物を得た。

(Base oil)
The base oils used in Examples and Comparative Examples of the present invention are as follows.
Synthetic oil 1: ExxonMobil Spectra Syn (poly-α-olefin)
Synthetic oil 2: NOF CORPORATION Unistar H-334R (polyol ester type)
Synthetic oil 3: NOF Corporation Unistar MB-881 (polyoxyethylene monoester type)
Mineral oil A: Diana Fresia P46 manufactured by Idemitsu Kosan Co., Ltd.
[Example 1]
(Preparation of lubricating oil composition)
_{Fullerene (Nanom (registered trademark) mix ST C 60} : 60% by mass, C ₇₀ : 25% by mass, the balance is a mixture of other higher-order fullerenes) in 100 g of synthetic oil as a base oil 0 .005 g and 20 g of the lubrication adjuster NH-C8 were added, and the mixture was stirred at room temperature using a stirrer for 36 hours and then filtered through a 0.1 μm mesh membrane filter to obtain a lubricating oil composition.

The content of the lubricant adjusting agent in the obtained lubricating oil composition is 20 parts by mass with respect to 100 parts by mass of the base oil. The content of the lubricating oil composition in the lubricating oil composition was calculated from the amount of the lubricating oil charged with respect to 100 parts by mass of the base oil. The content of fullerene in the lubricating oil composition is 0.025 parts by mass when the lubricating oil is 100 parts by mass, and 0.00500 parts by mass when the base oil is 100 parts by mass. The content of fullerene in the lubricating oil composition was calculated from the amount of fullerene dissolved in the lubricating oil composition when 100 parts by mass of each of the lubricating adjusting agent and the base oil in the lubricating oil composition was taken. The amount of dissolved fullerenes was confirmed by high performance liquid chromatography. Development of 1: 1 (volume ratio) of toluene and methanol using a high performance liquid chromatograph (1200 series manufactured by Azilent Technology Co., Ltd.) and column YMC-Pack ODS-AM (manufactured by YMC Co., Ltd., 150 mm x 4.6). With a solvent, the absorbance at a wavelength of 309 nm was detected, the fullerene concentration in the lubricating oil composition was measured, and the amount of fullerene dissolved in the lubricating oil composition was calculated.
(Abrasion resistance evaluation)
The wear resistance of the lubricating oil composition was evaluated by a ball-on-disc tribometer (manufactured by Antonioparr). Using a SUJ2 ball with a diameter of 6 mm, slide it so as to draw a concentric trajectory on one main surface of the substrate (made by SUJ2) coated with the lubricating oil composition under the conditions of a load of 15 N and a speed of 5 cm / sec. I moved it. The rubbing surface (circular) of the ball surface when the sliding distance was 300 m in total was observed with an optical microscope, and the diameter of the rubbing surface was measured. The results are shown in Table 1. In this evaluation, the smaller the diameter of the rubbing surface, the better the wear resistance (measurement of lamella length).
The lamella length of the lubricating oil composition was measured by a method according to the surface tension test method specified in 7.3 of Japanese Industrial Standard JIS K2241: 2000. Using a surface tension meter DY-500 (manufactured by Kyowa Interface Science Co., Ltd.), put about 20 mL of the lubricating oil composition into a glass chalet (depth 20 mm, inner diameter 75 mm), install it on the stage of the surface tension meter, and make it made of platinum. Using a ring with a diameter of 14.4 mm, the stage ascending speed was 0.5 mm / sec, the stage descending speed was 0.1 mm / sec, and the immersion distance of the ring in the lubricating oil composition was 2.5 mm. From the graph of the position of and the tension acting on the ring, the moving distance of the stage from the time when the force to pull down the ring showed the maximum value to the time when the liquid film was broken and became zero was calculated as the lamella length. This measurement was performed in an environment of 25 ± 2 ° C. The results are shown in Table 1.
[Example 2]
In the preparation of the lubricating oil composition, the lubricating oil composition was prepared in the same manner as in Example 1 except that the heat treatment step was carried out at 150 ° C. for 12 hours in a nitrogen gas atmosphere after filtering, and the abrasion resistance was evaluated. Lamella length measurement was performed. The measurement results are shown in Table 1.
[Examples 3 to 21, Comparative Examples 1 to 12]

A lubricating oil composition was prepared in the same manner as in Example 1 except for the base oil, the type of lubricating oil, their contents, and the fullerene content, and each measurement was carried out. The lubricating oil compositions of Examples 3 to 21 and Comparative Examples 1 to 12 were prepared so as to be the lubricating oil compositions having the compositions shown in Table 1, respectively.

「含有量^※１」は、基油１００質量部に対して、潤滑調整剤の含有量を意味する。「含有量^※２」は、潤滑調整剤１００質量部対して、フラーレンの含有量を意味する。「含有量^※３」は、基油１００質量部に対して、フラーレンの含有量を意味する。

"Content ^{* 1} " means the content of the lubrication adjuster with respect to 100 parts by mass of the base oil. "Content ^{* 2} " means the content of fullerene with respect to 100 parts by mass of the lubricating regulator. "Content ^{* 3} " means the content of fullerene with respect to 100 parts by mass of the base oil.

According to the results in Table 1, for Examples and Comparative Examples having the same base oil type, the diameter of the rubbing surface of the balls was smaller and the lamella length was longer in the Examples as compared with the Comparative Examples, resulting in excellent resistance. It was shown to have abrasion resistance and film formation property. Further, in Comparative Examples 1, 4, 7, and 10 in which only fullerene was added, the diameter of the rubbing surface of the ball was reduced and the lamella length was reduced as compared with Comparative Examples 3, 6, 9, and 12 containing only the respective base oils. Prolongation was observed, but is still inadequate compared to the examples containing the same type of base oil. On the other hand, Comparative Examples 2, 5, 8 and 11 to which only the lubrication adjusting agent was added had the same lamella length as those of Comparative Examples 3, 6, 9 and 12 containing only the respective base oils, but the rubbing surface of the ball. As the diameter increased, the wear resistance deteriorated. From these results, it is considered that the wear resistance and seizure resistance of the lubricating oil composition were improved by the interaction between the lubrication regulator and the fullerene. Further, in the heat-treated lubricating oil composition (Example 2), the diameter of the rubbing surface of the ball is smaller and the lamella length is longer than in Example 1. It was found that the heat treatment further improved the wear resistance and the seizure resistance.

This application is based on Japanese Patent Application No. 2018-243901 filed on December 27, 2018, the entire contents of which are incorporated herein by reference.

Claims (11)

Base oil and
With fullerenes
Lubrication regulator and, including
The lubricant adjusting agents include hydrindan, naphthalene, 1,2,3,4, -tetrahydronaphthalene, tetrahydrodicyclopentadiene, decahydronaphthalene, cyclododecatriene, cyclododecane, dodecahydrofluorene, anthracene, phenanthracene, 9, A lubricating oil composition which is at least one selected from 10-dihydroanthracene, hexadecahydropyrene, and compounds in which at least one hydrogen atom thereof is substituted with a substituent. The substituent of the lubrication regulator is
Halogen atom,
Hydroxy group,
Carboxy group,
Amino group,
Hydrocarbon groups with 1 to 20 carbon atoms,
A group having an ether bond having 1 to 20 carbon atoms,
A group having an ester bond having 1 to 20 carbon atoms,
A group having a disulfide bond having 1 to 20 carbon atoms, and a group having 1 to 20 carbon atoms having at least one of a halogen atom, a hydroxy group, a carboxy group, and an amino group.
The lubricating oil composition according to claim 1, which is at least one selected from. The group having an ether bond having 1 to 20 carbon atoms, the group having an ester bond having 1 to 20 carbon atoms, and the group having a disulfide bond having 1 to 20 carbon atoms are halogen atoms, hydroxy groups, carboxy groups, and the like. And the lubricating oil composition according to claim 2, which has at least one amino group. The lubricating oil composition according to any one of claims 1 to 3, wherein the total molecular weight of the substituents in the lubricating oil adjusting agent is 60% or less of the molecular weight of the lubricating oil adjusting agent. The lubricating oil composition according to any one of claims 1 to 4, wherein the base oil is a synthetic oil. The fullerene, the lubricating oil composition according to claim 1 comprising a C _60. The lubricating oil composition according to any one of claims 1 to 6, wherein the lubricating oil is contained in an amount of 1 to 100 parts by mass with respect to 100 parts by mass of the base oil. The lubricating oil composition according to any one of claims 1 to 7, wherein the fullerene is contained in an amount of 0.001 to 1.000 parts by mass with respect to 100 parts by mass of the lubricant adjusting agent. The method for producing a lubricating oil composition according to any one of claims 1 to 8, further comprising a mixing step of mixing a base oil, a fullerene, and a lubricating adjusting agent. The method for producing a lubricating oil composition according to claim 9, further comprising a heat treatment step after the mixing step. The method for producing a lubricating oil composition according to claim 10, wherein the heat treatment temperature in the heat treatment step is 100 to 250 ° C.