JP4524102B2 - Lubricating oil composition - Google Patents

Description

  The present invention relates to a lubricating oil composition.

  When a stick-slip occurs on a sliding guide surface such as a machining table of a machine tool, the frictional vibration is directly transferred to the workpiece, resulting in a problem that the machining accuracy is reduced or the tool life is reduced due to the vibration. Will occur. Therefore, the sliding guide surface lubricating oil is required to exhibit a high anti-stick slip property between the metal surface and the metal surface in addition to low friction (a small friction coefficient).

  In many machine tools, the sliding guide surface lubricant is mixed with the machining fluid of the workpiece. In particular, when a water-soluble cutting fluid is used as the machining fluid, the mixing of the lubricating oil for the sliding guide surface may cause deterioration of the water-soluble cutting fluid (deterioration of cutting performance, acceleration of decay, shortening of mineral oil life, waste liquid treatment cost Is one of the causes.

  Therefore, as for the performance of the lubricating oil for the sliding guide surface, in addition to excellent lubrication characteristics such as reduction of the coefficient of friction on the sliding guide surface and prevention of stick-slip, the case where it is mixed with water-soluble cutting fluid is considered. Therefore, it is required that the water-soluble cutting fluid is excellent in separability and does not adversely affect various performances of the water-soluble cutting fluid.

  Regarding prevention of stick-slip, for example, a lubricating oil composition in which a sulfur compound, an ester and a fatty acid are combined (see, for example, Patent Document 1), and a lubricating oil composition in which a sulfur compound and an amine salt of a phosphorus compound are combined ( For example, use of patent document 2) etc. is proposed.

  Regarding friction characteristics, for example, a lubricating oil composition (for example, see Patent Document 3) in which an acidic phosphate ester or an alkylammonium salt thereof, phosphorous acid, a fatty acid and a linear alkylamine are combined, a phosphorus compound is used. Lubricating oil composition for sliding guide surfaces (for example, see Patent Document 4), machine tool oil composition in which a glyceryl ether compound and a phosphate ester or an amine salt thereof are combined (for example, see Patent Document 5) The use of is proposed.

As for separability from the water-soluble cutting fluid, for example, a lubricating oil composition in which a carboxylic acid and / or ester, an organic acid salt of an alkali metal, and a phosphite and an amine salt thereof are combined (for example, a patent document). 6), a lubricating oil composition in which a carboxylic acid and / or ester, an organic acid salt of an alkali metal, and a phosphate ester are combined (see, for example, Patent Document 7) has been proposed.
JP 57-67693 A Japanese Patent Laid-Open No. 51-74005 JP-A-8-134488 JP-A-8-209175 JP-A-11-209775 Japanese Patent Laid-Open No. 9-328696 JP-A-11-1693

  However, even with the above-described conventional lubricating oil composition, it is not always easy to balance all of the anti-stick-slip properties, the friction properties, and the separability from the water-soluble cutting fluid. There is room for improvement.

  The present invention has been made in view of such circumstances, and its purpose is to achieve all of anti-stick-slip properties, friction properties, and separability from water-soluble cutting fluid at a high level in a well-balanced manner. And providing a lubricating oil composition.

  As a result of intensive studies to achieve the above object, the present inventors have found that the above-mentioned problems can be solved by incorporating an acidic phosphate ester and a saturated fatty acid having a specific carbon number in a predetermined base oil, The present invention has been completed.

That is, the lubricating oil composition of the present invention contains at least one base oil selected from mineral oils, fats and oils, acidic phosphate esters, and saturated fatty acids having 12 to 14 carbon atoms. And

  The lubricating oil composition of the present invention preferably further contains a sulfur-based extreme pressure agent.

Also. Although the lubricating oil composition of the present invention can be used for various applications, a preferred embodiment thereof is a lubricating oil composition for a sliding guide surface.
Moreover, the lubricating oil composition of the present invention further contains a saturated fatty acid having 16 carbon atoms, and the saturated fatty acid having 16 carbon atoms occupies the total amount of the saturated fatty acid having 12 to 14 carbon atoms and the saturated fatty acid having 16 carbon atoms. The ratio is preferably 50% by mass or less.

  According to the lubricating oil composition of the present invention, all of stick-slip prevention, friction characteristics, and separability from water-soluble cutting fluid can be achieved at a high level in a well-balanced manner. Therefore, the lubricating oil composition of the present invention is very useful in terms of stabilizing the operation of the machine tool and extending the life.

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

  The lubricating oil composition of the present invention is based on at least one selected from mineral oil, fats and oils and synthetic oils.

  Examples of mineral oil base oils that can be used in the present invention include solvent desorption, solvent extraction, hydrocracking, solvent dewaxing for lubricating oil fractions obtained by atmospheric and vacuum distillation of crude oil. And paraffinic or naphthenic mineral oils obtained by appropriately combining one or more purification means such as catalytic dewaxing, hydrorefining, sulfuric acid washing, and clay treatment.

  Examples of the fats and oils include beef tallow, lard, soybean oil, rapeseed oil, rice bran oil, coconut oil, palm oil, palm kernel oil, and hydrogenated products thereof.

  Synthetic oils include, for example, poly-α-olefins (ethylene-propylene copolymers, polybutenes, 1-octene oligomers, 1-decene oligomers, and hydrides thereof), alkylbenzenes, alkylnaphthalenes, monoesters ( Butyl stearate, octyl laurate), diester (ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, di-2-ethylhexyl sepacate, etc.), polyester (trimellitic acid ester, etc.), polyol Esters (trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol-2-ethylhexanoate, pentaerythritol pelargonate, etc.), polyoxyal Glycol, polyphenyl ether, dialkyl diphenyl ether, (such as tricresyl phosphate) phosphoric acid ester, fluorine-containing compound (perfluoropolyether, such as fluorinated polyolefins), such as silicone oil can be exemplified.

  In the lubricating oil composition of the present invention, one of the above-described base oils may be used alone or in combination of two or more.

The viscosity of the base oil used in the present invention is not particularly limited, preferably has kinematic viscosity at 40 ° C. is in the range of 10~700mm ² / s, it is more preferably in the range of 15~500mm ² / s. Further, the content of the base oil is not particularly limited, but is preferably in the range of 50 to 99.98% by mass based on the total amount of the composition.

  The lubricating oil composition of the present invention contains an acidic phosphate ester. The above-described effects of the lubricating oil composition of the present invention are particularly effective when compared to normal phosphates and phosphites due to the synergistic effect of acidic phosphates and specific saturated fatty acids described below. In particular, this is based on the knowledge of the present inventors that the sliding characteristics are dramatically improved.

  The acidic phosphate ester is a compound represented by the following general formula (1).

［式中、Ｒ^１及びＲ^２は同一でも異なっていてもよく、それぞれ水素原子又は炭化水素基（好ましくは炭素数１〜３０の炭化水素基）を表し、Ｒ^１又はＲ^２の少なくとも一方は炭化水素基である。］
Ｒ^１及びＲ^２で表される炭化水素基としては、炭素数１〜３０の炭化水素基が好ましい。具体的には例えば、メチル基、エチル基、プロピル基、ブチル基、ペンチル基、ヘキシル基、ヘプチル基、オクチル基、ノニル基、デシル基、ウンデシル基、ドデシル基、トリデシル基、テトラデシル基、ペンタデシル基、ヘキサデシル基、ヘプタデシル基、オクタデシル基、ノナデシル基、イコシル基、ヘニコシル基、トリコシル基、テトラコシル基、ペンタコシル基、ヘキサコシル基、ヘプタコシル基、オクタコシル基、ノナコシル基、トリアコンチル基等のアルキル基（これらのアルキル基は直鎖状でも分枝状でもよい）；ブテニル基、ペンテニル基、ヘキセニル基、ヘプテニル基、オクテニル基、ノネニル基、デセニル基、ウンデセニル基、ドデセニル基、トリデセニル基、テトラデセニル基、ペンタデセニル基、ヘキサデセニル基、ヘプタデセニル基、オクタデセニル基、ノナデセニル基、イコセニル基、ヘニコセニル基、トリコセニル基、テトラコセニル基、ペンタコセニル基、ヘキサコセニル基、ヘプタコセニル基、オクタコセニル基、ノナコセニル基、トリアコンテニル基等のアルケニル基（これらのアルケニル基は直鎖状でも分枝状でもよく、また二重結合の位置は任意である）；シクロペンチル基、シクロヘキシル基、シクロヘプチル基等の炭素数５〜７のシクロアルキル基；メチルシクロペンチル基、ジメチルシクロペンチル基、メチルエチルシクロペンチル基、ジエチルシクロペンチル基、メチルシクロヘプチル基、ジメチルシクロヘキシル基、メチルエチルシクロヘキシル基、ジエチルシクロヘキシル基、メチルシクロヘプチル基、ジメチルシクロヘプチル基、メチルエチルシクロヘプチル基、ジエチルシクロヘキシル基等の炭素数６〜１１のアルキルシクロヘキシル基（アルキル基のシクロヘキシル基への置換位置は任意である）；フェニル基、ナフチル基等のアリール基；トリル基、キシリル基、エチルフェニル基、プロピルフェニル基、ブチルフェニル基、ペンチルフェニル基、ヘキシルフェニル基、ヘプチルフェニル基、オクチルフェニル基、ノニルフェニル基、デシルフェニル基、ウンデシルフェニル基、ドデシルフェニル基等の炭素数７〜１８のアルキルアリール基（アルキル基は直鎖状でも分枝状でもよく、アルキル基のアリール基への置換位置は任意である）；ベンジル基、フェニルエチル基、フェニルプロピル基、フェニルブチル基、フェニルペンチル基、フェニルヘキシル基等の炭素数７〜１２のアリールアルキル基（アルキル基は直鎖状でも分枝状でもよい）などが挙げられる。

[Wherein, R ¹ and R ² may be the same or different and each represents a hydrogen atom or a hydrocarbon group (preferably a hydrocarbon group having 1 to 30 carbon atoms), and at least one of R ¹ or R ² is It is a hydrocarbon group. ]
The hydrocarbon group represented by R ¹ and R ² is preferably a hydrocarbon group having 1 to 30 carbon atoms. Specifically, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group Alkyl groups such as hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, henicosyl group, tricosyl group, tetracosyl group, pentacosyl group, hexacosyl group, heptacosyl group, octacosyl group, nonacosyl group, triacontyl group, etc. The group may be linear or branched); butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl Base Heptadecenyl group, octadecenyl group, nonadecenyl group, icocenyl group, henicocenyl group, tricocenyl group, tetracocenyl group, pentacocenyl group, hexacocenyl group, heptacocenyl group, octacocenyl group, nonacocenyl group, triacontenyl group and other alkenyl groups (these alkenyl groups are Linear or branched, and the position of the double bond is arbitrary); a cycloalkyl group having 5 to 7 carbon atoms such as a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group; a methylcyclopentyl group, a dimethylcyclopentyl group Methylethylcyclopentyl group, diethylcyclopentyl group, methylcycloheptyl group, dimethylcyclohexyl group, methylethylcyclohexyl group, diethylcyclohexyl group, methylcycloheptyl group, dimethylcycloheptyl group An alkylcyclohexyl group having 6 to 11 carbon atoms such as alkyl group, methylethylcycloheptyl group and diethylcyclohexyl group (the substitution position of the alkyl group to the cyclohexyl group is arbitrary); aryl group such as phenyl group and naphthyl group; Group, xylyl group, ethylphenyl group, propylphenyl group, butylphenyl group, pentylphenyl group, hexylphenyl group, heptylphenyl group, octylphenyl group, nonylphenyl group, decylphenyl group, undecylphenyl group, dodecylphenyl group, etc. A C7-18 alkylaryl group (the alkyl group may be linear or branched, and the substitution position of the alkyl group to the aryl group is arbitrary); benzyl group, phenylethyl group, phenylpropyl group, Phenylbutyl group, phenylpentyl group, phenylhexyl And an arylalkyl group having 7 to 12 carbon atoms such as a group (the alkyl group may be linear or branched).

  Among these hydrocarbon groups, an alkyl group having 1 to 30 carbon atoms and an alkenyl group having 2 to 30 carbon atoms are preferable from the viewpoint of friction characteristics. In addition, the number of carbon atoms of the alkyl group and alkenyl group is preferably 8 or more, and more preferably 12 or more, from the viewpoint of friction characteristics. On the other hand, from the viewpoint of solubility in base oil, the carbon number of the alkyl group and alkenyl group is preferably 22 or less, and more preferably 18 or less. Furthermore, the alkyl group and the alkenyl group may be either linear or branched, but are preferably linear from the viewpoint of friction characteristics.

The acidic phosphate ester used in the present invention includes a compound (phosphate monoester) in which one of R ^{1 and} R ^{2 in} the general formula (1) is a hydrogen atom and the other is a hydrocarbon group, and R ^A compound (phosphoric diester) in which both ¹ and R ² are hydrocarbon groups is included. In the present invention, either phosphoric acid monoester or phosphoric acid diester may be used alone, or a mixture of phosphoric acid monoester and phosphoric acid diester may be used. It is preferable to use a mixture of monoester and phosphoric acid diester. When the mixture is used, the mixing ratio of phosphoric acid monoester / phosphoric diester is preferably 10/90 to 90/10, more preferably 20/80 to 80/20, and 30/70 to 70 /. More preferably, it is 30.

  In the lubricating oil composition of the present invention, the content of the acidic phosphate ester is arbitrary, but is 0.001% by mass or more based on the total amount of the composition from the viewpoint of the friction characteristics of the resulting lubricating oil composition. Is preferable, 0.01 mass% or more is more preferable, and 0.1 mass% or more is even more preferable. In addition, since the obtained lubricating oil composition is superior in separability from the water-soluble cutting fluid, and further improvement in friction characteristics may not be expected even if it is further contained, the content of acidic phosphate is The total amount of the composition is preferably 10% by mass or less, more preferably 3% by mass or less, and even more preferably 1% by mass or less.

  The lubricating oil composition of the present invention contains a saturated fatty acid having 12 to 16 carbon atoms. Specific examples of the saturated fatty acid having 12 to 16 carbon atoms include lauric acid, myristic acid, and palmitic acid. These saturated fatty acids may be used individually by 1 type, or may be used as a mixture of 2 or more types. When using a mixture, the average carbon number of the mixture is preferably 12 to 14 from the viewpoint of stability during low-temperature storage and separability from a water-soluble cutting fluid. Moreover, when a C16 saturated fatty acid is contained, it is preferable that the ratio is 50 mass% or less.

  In the lubricating oil composition of the present invention, the content of the saturated fatty acid having 12 to 16 carbon atoms is not particularly limited, but is 0.001% by mass based on the total amount of the composition from the viewpoint of the frictional characteristics of the resulting lubricating oil composition. Preferably, it is 0.01% by mass or more, and more preferably 0.1% by mass or more. In addition, the resulting lubricating oil composition is excellent in stability at low temperatures and separability from water-soluble cutting fluid, and further improvement in friction characteristics may not be expected even if it is contained more than that, carbon. The content of saturated fatty acids of several 12 to 16 is preferably 5% by mass or less, more preferably 1% by mass or less, and further preferably 0.5% by mass or less, based on the total amount of the composition. preferable.

  The lubricating oil composition of the present invention may be composed of only the above-described base oil, acidic phosphate ester and saturated fatty acid having 12 to 16 carbon atoms, but preferably further contains a sulfur-based extreme pressure agent. By including a sulfur-based additive, extreme pressure properties and friction characteristics can be further enhanced.

  Specific examples of sulfur-based extreme pressure agents used in the present invention include sulfurized fats and oils, sulfurized fatty acids, sulfurized esters, sulfurized olefins, dihydrocarbyl polysulfides, thiadiazole compounds, alkylthiocarbamoyl compounds, thiocarbamate compounds, thioterpene compounds, dialkylthiols. Examples thereof include dipropionate compounds. These sulfur type extreme pressure agents may be used individually by 1 type, and may be used as a 2 or more types of mixture.

  Sulfurized fats and oils are obtained by reacting sulfur and sulfur-containing compounds with fats and oils (lard oil, whale oil, vegetable oil, fish oil, etc.), and the sulfur content is not particularly limited, but is generally 5 to 30% by mass. Those are preferred. Specific examples thereof include sulfurized lard, sulfurized rapeseed oil, sulfurized castor oil, sulfurized soybean oil, sulfurized rice bran oil, and mixtures thereof.

  Examples of sulfurized fatty acids include sulfurized oleic acid, and examples of sulfurized esters include sulfurized methyl oleate, sulfurized rice bran fatty acid octyl, and mixtures thereof.

  Examples of the sulfurized olefin include a compound represented by the following general formula (2). This compound is obtained by reacting an olefin having 2 to 15 carbon atoms or a dimer to tetramer thereof with a sulfurizing agent such as sulfur or sulfur chloride, and propylene, isobutene, diisobutene and the like are preferable.

R ³ -S _a -R ⁴ (2)
[Wherein, R ² represents an alkenyl group having 2 to 15 carbon atoms, R ³ represents an alkyl group or alkenyl group having 2 to 15 carbon atoms, and a represents an integer of 1 to 8. ]
Dihydrocarbyl polysulfide is a compound represented by the following general formula (3). Here, when R ⁵ and R ⁶ are alkyl groups, they are referred to as alkyl sulfides.

_{^{R 5 -S b -R 6 (3}} )
[Wherein, R ⁵ and R ⁶ may be the same or different and each represents a chain alkyl group having 1 to 20 carbon atoms or a cyclic alkyl group, an aryl group having 6 to 20 carbon atoms, and an alkyl having 7 to 20 carbon atoms. An aryl group or a C7-20 arylalkyl group is shown, b shows the integer of 1-8. ]
Specific examples of R ⁵ and R ⁶ in the general formula (3) include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, Various pentyl groups, various hexyl groups, various heptyl groups, various octyl groups, various nonyl groups, various decyl groups, various dodecyl groups, cyclohexyl groups, cyclooctyl groups, phenyl groups, naphthyl groups, tolyl groups, xylyl groups, benzyl groups, Examples thereof include a phenethyl group.

  Examples of the dihydrocarbyl polysulfide represented by the general formula (3) include dibenzyl polysulfide, various dinonyl polysulfides, various didodecyl polysulfides, various dibutyl polysulfides, various dioctyl polysulfides, diphenyl polysulfide, dicyclohexyl polysulfide, and mixtures thereof. Preferable examples can be given.

  Examples of the thiadiazole compound include 1,3,4-thiadiazole represented by the following general formula (4), 1,2,4-thiadiazole compound represented by the following general formula (5), and the following general formula (6). The 1,4,5-thiadiazole compound represented by these is mentioned.

［式中、Ｒ^７及びＲ^８は同一でも異なっていてもよく、それぞれ水素原子又は炭素数１〜２０の炭化水素基を示し、ｃ及びｄは同一でも異なっていてもよく、それぞれ０〜８の整数を示す］
このようなチアジアゾール化合物の具体例としては、２，５−ビス（ｎ−ヘキシルジチオ）−１，３，４−チアジアゾール、２，５−ビス（ｎ−オクチルジチオ）−１，３，４−チアジアゾール、２，５−ビス（ｎ−ノニルジチオ）−１，３，４−チアジアゾール、２，５−ビス（１，１，３，３−テトラメチルブチルジチオ）−１，３，４−チアジアゾール、３，５−ビス（ｎ−ヘキシルジチオ）−１，２，４−チアジアゾール、３，５−ビス（ｎ−オクチルジチオ）−１，２，４−チアジアゾール、３，５−ビス（ｎ−ノニルジチオ）−１，２，４−チアジアゾール、３，５−ビス（１，１，３，３−テトラメチルブチルジチオ）−１，２，４−チアジアゾール、４，５−ビス（ｎ−ヘキシルジチオ）−１，２，３−チアジアゾール、４，５−ビス（ｎ−オクチルジチオ）−１，２，３−チアジアゾール、４，５−ビス（ｎ−ノニルジチオ）−１，２，３−チアジアゾール、４，５−ビス（１，１，３，３−テトラメチルブチルジチオ）−１，２，３−チアジアゾールおよびこれらの混合物などを好ましく挙げることができる。

[Wherein, R ⁷ and R ⁸ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms; c and d may be the same or different; Indicates an integer]
Specific examples of such thiadiazole compounds 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, 3,5-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-hexyldithio) -1,2 , 3-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) Preferred examples include -tetramethylbutyldithio) -1,2,3-thiadiazole and a mixture thereof.

  Examples of the alkylthiocarbamoyl compound include a compound represented by the following general formula (7).

［式中、Ｒ^９〜Ｒ^１２は同一でも異なっていてもよく、それぞれ炭素数１〜２０のアルキル基を示し、ｅは１〜８の整数を示す。］
このようなアルキルチオカルバモイル化合物の具体例としては、ビス（ジメチルチオカルバモイル）モノスルフィド、ビス（ジブチルチオカルバモイル）モノスルフィド、ビス（ジメチルチオカルバモイル）ジスルフィド、ビス（ジブチルチオカルバモイル）ジスルフィド、ビス（ジアミルチオカルバモイル）ジスルフィド、ビス（ジオクチルチオカルバモイル）ジスルフィドおよびこれらの混合物などを好ましく挙げることができる。

[Wherein, R ^{9 to} R ¹² may be the same or different and each represents an alkyl group having 1 to 20 carbon atoms, and e represents an integer of 1 to 8. ]
Specific examples of such alkylthiocarbamoyl compounds include bis (dimethylthiocarbamoyl) monosulfide, bis (dibutylthiocarbamoyl) monosulfide, bis (dimethylthiocarbamoyl) disulfide, bis (dibutylthiocarbamoyl) disulfide, and bis (diamil). Preferable examples include thiocarbamoyl) disulfide, bis (dioctylthiocarbamoyl) disulfide, and mixtures thereof.

  As an alkyl thiocarbamate compound, the compound shown by following General formula (8) is mentioned, for example.

［式中、Ｒ^１３〜Ｒ^１６は同一でも異なっていてもよく、それぞれ炭素数１〜２０のアルキル基を示し、Ｒ^１７は炭素数１〜１０のアルキル基を示す。］
このようなアルキルチオカーバメート化合物の具体例としては、メチレンビス（ジブチルジチオカーバメート）、メチレンビス［ジ（２−エチルヘキシル）ジチオカーバメート］などを好ましく挙げることができる。

[Wherein, R ^{13 to} R ¹⁶ may be the same or different and each represents an alkyl group having 1 to 20 carbon atoms, and R ¹⁷ represents an alkyl group having 1 to 10 carbon atoms. ]
Preferable examples of such alkylthiocarbamate compounds include methylenebis (dibutyldithiocarbamate), methylenebis [di (2-ethylhexyl) dithiocarbamate] and the like.

  Further, examples of the thioterpene compound include a reaction product of phosphorus pentasulfide and pinene, and examples of the dialkylthiodipropionate compound include dilauryl thiodipropionate, distearyl thiodipropionate, and a mixture thereof. be able to.

  In the lubricating oil composition of the present invention, the content of the sulfur-based extreme pressure agent is arbitrary, but is 0.1% by mass or more based on the total amount of the composition from the viewpoint of the friction characteristics of the resulting lubricating oil composition. Is preferably 0.5% by mass or more, and more preferably 1% by mass or more. In addition, since the obtained lubricating oil composition is more excellent in separability from the water-soluble cutting fluid, and further improvement in friction characteristics may not be expected even if it is further contained, the content of the component (B) is It is preferably 20% by mass or less, more preferably 10% by mass or less, and still more preferably 5% by mass or less based on the total amount of the composition.

  The lubricating oil composition of the present invention preferably further contains a polyalkylene glycol derivative described later. By containing polyalkylene glycol, the separation property from the water-soluble machinability can be further enhanced.

  Preferable examples of the polyalkylene glycol used in the present invention include compounds represented by the following general formula (9).

^{_{R 17 O- (EO) l -}} (R 19 O) m - (EO) n -R 18 (9)
[In Formula (1), R ¹⁷ and R ¹⁸ may be the same or different and each represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, EO represents an oxyethylene group, and R ¹⁹ O represents a carbon number. Represents 3 to 6 oxyalkylene groups, and l, m and n may be the same or different and each represents an integer of 1 to 50]
In general formula (9), the alkyl group as R ¹⁷ and R ¹⁸ may be linear, branched or cyclic. Specific examples of such an alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, various butyl groups, various pentyl groups, various hexyl groups, cyclopentyl groups, and cyclohexyl groups.

Moreover, R < ¹⁹ > O in General formula (9) is a C3-C6 oxyalkylene group, As an oxyalkylene container of a repeating unit, an oxypropylene group (PO), an oxybutylene group, an oxypentylene group, Examples include oxyhexylene group. Among these, an oxypropylene group is preferable because it is excellent in separability from a water-soluble cutting fluid.

In the polyalkylene glycol derivative according to the present invention, as is clear from the fact that l, m and n representing the number of repetitions of EO, R ¹⁹ O and EO are each an integer of 1 to 50, the oxyalkylene chain — (R ¹⁹ O) is a block copolymer in which both ends of _m- are bonded to oxyethylene chains (EO) ₁ and (EO) _n . When a polyalkylene glycol derivative in which any one of l, m, and n is 0, the separability from the water-soluble cutting fluid is insufficient. In addition, each of l, m, and n is preferably a value such that the average molecular weight of the polyalkylene glycol derivative represented by the general formula (9) is 500 to 5,000. Further, the ratio (l + n) / (l + m + n) of the sum of l and n to the sum of l, m and n is preferably 0.05 to 0.8, and is 0.08 to 0.7. More preferably, it is more preferably 0.09 to 0.5. When (l + n) / (l + m + n) is within the above range, the separability from the water-soluble cutting fluid tends to be further improved.

In addition, when m is 2 or more, m pieces of R ¹⁹ O may be the same or different. When the oxyalkylene chain (R ³ O) _m is composed of two or more types of R ³ O, the oxyalkylene chain may be either a block copolymer chain or a random copolymer chain.

  In this invention, the said polyalkylene glycol derivative may be used individually by 1 type, and may be used in combination of 2 or more type. Further, the content is preferably 0.0001 to 1% by mass and more preferably 0.001 to 0.1% by mass based on the total amount of the composition.

In the lubricating oil composition of the present invention, an amine as an oily agent or a rust inhibitor can be contained. Examples of such amine salts include monoamines, polyamines, and alkanolamines as amines according to the present invention. Specific examples of the monoamine include monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monopropylamine (including all isomers), dipropylamine (including all isomers), Propylamine (including all isomers), monobutylamine (including all isomers), dibutylamine (including all isomers), tributylamine (including all isomers), monopentylamine (all including all isomers) Including isomers), dipentylamine (including all isomers), tripentylamine (including all isomers), monohexylamine (including all isomers), dihexylamine (including all isomers) ), Monoheptylamine (including all isomers), diheptylamine (including all isomers) , Monooctylamine (including all isomers), dioctylamine (including all isomers), monononylamine (including all isomers), monodecylamine (including all isomers), monoundecyl ( Including all isomers), monododecylamine (including all isomers), monotridecylamine (including all isomers), monotetradecylamine (including all isomers), monopentadecylamine (Including all isomers), monohexadecylamine (including all isomers), monoheptadecylamine (including all isomers), monooctadecylamine (including all isomers), monononadecyl Amine (including all isomers), monoicosylamine (including all isomers), monohenicosylamine (including all isomers), monodocosylamine (Including all isomers), monotricosylamine (including all isomers), dimethyl (ethyl) amine, dimethyl (propyl) amine (including all isomers), dimethyl (butyl) amine (all Isomers), dimethyl (pentyl) amine (including all isomers), dimethyl (hexyl) amine (including all isomers), dimethyl (heptyl) amine (including all isomers), dimethyl ( Octyl) amine (including all isomers), dimethyl (nonyl) amine (including all isomers), dimethyl (decyl) amine (including all isomers), dimethyl (undecyl) amine (all isomers) ), Dimethyl (dodecyl) amine (including all isomers), dimethyl (tridecyl) amine (including all isomers), dimethyl (tetradecyl) ) Amine (including all isomers), dimethyl (pentadecyl) amine (including all isomers), dimethyl (hexadecyl) amine (including all isomers), dimethyl (heptadecyl) amine (including all isomers) ), Dimethyl (octadecyl) amine (including all isomers), dimethyl (nonadecyl) amine (including all isomers), dimethyl (icosyl) amine (including all isomers), dimethyl (henicosyl) amine Alkylamines such as (including all isomers), dimethyl (tricosyl) amine (including all isomers);
Monovinylamine, divinylamine, trivinylamine, monopropenylamine (including all isomers), dipropenylamine (including all isomers), tripropenylamine (including all isomers), monobutenylamine (Including all isomers), dibutenylamine (including all isomers), tributenylamine (including all isomers), monopentenylamine (including all isomers), dipentenylamine (all isomers) ), Tripentenylamine (including all isomers), monohexenylamine (including all isomers), dihexenylamine (including all isomers), monoheptenylamine (all isomers) ), Diheptenylamine (including all isomers), monooctenylamine (including all isomers), dioctenylamine (Including all isomers), monononenylamine (including all isomers), monodecenylamine (including all isomers), monoundecenyl (including all isomers), monododecenylamine (Including all isomers), monotridecenylamine (including all isomers), monotetradecenylamine (including all isomers), monopentadecenylamine (including all isomers), Monohexadecenylamine (including all isomers), monoheptadecenylamine (including all isomers), monooctadecenylamine (including all isomers), monononadecenylamine (all isomers) ), Monoicosenylamine (including all isomers), monohenicocenylamine (including all isomers), monodocosenylamine (including all isomers), Trichoderma cell (including all isomers) cycloalkenyl amines alkenyl amines, such as;
Dimethyl (vinyl) amine, dimethyl (propenyl) amine (including all isomers), dimethyl (butenyl) amine (including all isomers), dimethyl (pentenyl) amine (including all isomers), dimethyl ( Hexenyl) amine (including all isomers), dimethyl (heptenyl) amine (including all isomers), dimethyl (octenyl) amine (including all isomers), dimethyl (nonenyl) amine (all isomers) ), Dimethyl (decenyl) amine (including all isomers), dimethyl (undecenyl) amine (including all isomers), dimethyl (dodecenyl) amine (including all isomers), dimethyl (tridecenyl) Amine (including all isomers), dimethyl (tetradecenyl) amine (including all isomers), dimethyl (pen Decenyl) amine (including all isomers), dimethyl (hexadecenyl) amine (including all isomers), dimethyl (heptadecenyl) amine (including all isomers), dimethyl (octadecenyl) amine (all isomers) ), Dimethyl (nonadecenyl) amine (including all isomers), dimethyl (icosenyl) amine (including all isomers), dimethyl (henicosenyl) amine (including all isomers), dimethyl (tricosenyl) Monoamines having alkyl and alkenyl groups such as amines (including all isomers);
Monobenzylamine, (1-phenyltyl) amine, (2-phenylethyl) amine (also known as monophenethylamine), dibenzylamine, bis (1-phenethyl) amine, bis (2-phenylethylene) amine (also known as diphenethylamine) Aromatic substituted alkylamines such as
C5-C16 cycloalkylamines such as monocyclopentylamine, dicyclopentylamine, tricyclopentylamine, monocyclohexylamine, dicyclohexylamine, monocycloheptylamine, dicycloheptylamine;
Monoamines having an alkyl group and a cycloalkyl group, such as dimethyl (cyclopentyl) amine, dimethyl (cyclohexyl) amine, dimethyl (cycloheptyl) amine;
(Methylcyclopentyl) amine (including all substituted isomers), bis (methylcyclopentyl) amine (including all substituted isomers), (dimethylcyclopentyl) amine (including all substituted isomers), bis (dimethylcyclopentyl) ) Amine (including all substituted isomers), (ethylcyclopentyl) amine (including all substituted isomers), bis (ethylcyclopentyl) amine (including all substituted isomers), (methylethylcyclopentyl) amine ( All substituted isomers included), bis (methylethylcyclopentyl) amine (including all substituted isomers), (diethylcyclopentyl) amine (including all substituted isomers), (methylcyclohexyl) amine (all substituted isomers) Isomers), bis (methylcyclohexyl) amine (all substituted isomers) ), (Dimethylcyclohexyl) amine (including all substituted isomers), bis (dimethylcyclohexyl) amine (including all substituted isomers), (ethylcyclohexyl) amine (including all substituted isomers), bis (Ethylcyclohexyl) amine (including all substituted isomers), (Methylethylcyclohexyl) amine (including all substituted isomers), (Diethylcyclohexyl) amine (including all substituted isomers), (Methylcycloheptyl) ) Amine (including all substituted isomers), bis (methylcycloheptyl) amine (including all substituted isomers), (dimethylcycloheptyl) amine (including all substituted isomers), (ethylcycloheptylamine) (Including all substituted isomers), (methylethylcycloheptyl) amine (all substituted isomers) And alkyl cycloalkylamines such as (diethylcycloheptyl) amine (including all substituted isomers), etc. The monoamines according to the present invention include monoamines (beef tallow amines) derived from fats and oils. Etc.).

Specific examples of the polyamine according to the present invention include ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, propylenediamine, dipropylenetriamine, tripropylenetetramine, tetrapropylenepentamine, and pentapropylene. Alkylene polyamines such as hexamine, butylenediamine, dibutylenetriamine, butylenetetramine, tetrabutylenepentamine, pentabylenehexamine;
N-methylethylenediamine, N-ethylethylenediamine, N-propylethylenediamine (including all isomers), N-butylethylenediamine (including all isomers), N-pentylethylenediamine (including all isomers), N -Hexylethylenediamine (including all isomers), N-heptylethylenediamine (including all isomers), N-octylethylenediamine (including all isomers), N-nonylethylenediamine (including all isomers) N-decylethylenediamine (including all isomers), N-undecyl (including all isomers), N-dodecylethylenediamine (including all isomers), N-tridecylethylenediamine (including all isomers) Including), N-tetradecylethylenediamine (including all isomers), -Pentadecylethylenediamine (including all isomers), N-hexadecylethylenediamine (including all isomers), N-heptadecylethylenediamine (including all isomers), N-octadecylethylenediamine (all isomers) N-nonadecylethylenediamine (including all isomers), N-icosylethylenediamine (including all isomers), N-henicosylethylenediamine (including all isomers), N-doco N-alkylethylenediamines such as silethylenediamine (including all isomers), N-tricosylethylenediamine (including all isomers);
N-vinylethylenediamine, N-propenylethylenediamine (including all isomers), N-butenylethylenediamine (including all isomers), N-pentenylethylenediamine (including all isomers), N-hexenylethylenediamine ( Including all isomers), N-heptenylethylenediamine (including all isomers), N-octenylethylenediamine (including all isomers), N-nonenylethylenediamine (including all isomers), N-decenylethylenediamine (including all isomers), N-undecenyl (including all isomers), N-dodecenylethylenediamine (including all isomers), N-tridecenylethylenediamine (including all isomers) All isomers), N-tetradecenylethylenediamine (including all isomers), N- Ntadecenylethylenediamine (including all isomers), N-hexadecenylethylenediamine (including all isomers), N-heptadecenylethylenediamine (including all isomers), N-octade Cenylethylenediamine (including all isomers), N-nonadecenylethylenediamine (including all isomers), N-icosenylethylenediamine (including all isomers), N-henicocenylethylenediamine N-alkenylethylenediamine such as (including all isomers), N-docosenylethylenediamine (including all isomers), N-tricosenylethylenediamine (including all isomers);
N-alkyldiethylenetriamine, N-alkenyldiethylenetriamine, N-alkyltriethylenetetramine, N-alkenyltriethylenetetramine, N-alkyltetraethylenepentamine, N-alkenyltetraethylenepentamine, N-alkylpentaethylenehexamine, N-alkenyl Pentaethylenehexamine, N-alkylpropylenediamine, N-alkenylpropylenediamine, N-alkyldipropylenetriamine, N-alkenyldipropylenetriamine, N-alkyltripropylenetetramine, N-alkenyltripropylenetetramine, N-alkyltetrapropylenepenta Min, N-alkenyltetrapropylenepentamine, N-alkylpentapropylenehexamine, N-alkenylpentapropylene Hexamine, N-alkylbutylenediamine, N-alkenylbutylenediamine, N-alkyldibutylenetriamine, N-alkenyldibutylenetriamine, N-alkyltributylenetetramine, N-alkenyltributylenetetramine, N-alkyltetrabutylenepentamine, N-alkyl or N-alkenyl alkylene polyamines such as N-alkenyltetrabutylenepentamine, N-alkylpentabylenehexamine, N-alkenylpentabylenehexamine and the like. The polyamine according to the present invention includes polyamines derived from fats and oils (such as beef tallow polyamine).

  Furthermore, as the alkanolamine according to the present invention, specifically, monomethanolamine, dimethanolamine, trimethanolamine, monoethanolamine, diethanolamine, triethanolamine, mono (n-propanol) amine, di (n- Propanol) amine, tri (n-propanol) amine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, monobutanolamine (including all isomers), dibutanolamine (including all isomers), tributanol Amine (including all isomers), monopentanolamine (including all isomers), dipentanolamine (including all isomers), tripentanolamine (including all isomers), mono Hexanolamine (all isomeric ), Dihexanolamine (including all isomers), monoheptanolamine (including all isomers), diheptanolamine (including all isomers), monooctanolamine (all isomers) ), Monononanolamine (including all isomers), monodecanolamine (including all isomers), monoundecanolamine (including all isomers), monododecanolamine (including all isomers) Isomers), monotridecanolamine (including all isomers), monotetradecanolamine (including all isomers), monopentadecanolamine (including all isomers), monohexa Decanolamine (including all isomers), diethyl monoethanolamine, diethyl monopropanolamine (including all isomers), diethyl Butanolamine (including all isomers), diethylmonopentanolamine (including all isomers), dipropylmonoethanolamine (including all isomers), dipropylmonopropanolamine (including all isomers) ), Dipropylmonobutanolamine (including all isomers), dipropylmonopentanolamine (including all isomers), dibutylmonoethanolamine (including all isomers), dibutylmonopropanolamine (including all isomers) Including all isomers), dibutyl monobutanolamine (including all isomers), dibutylmonopentanolamine (including all isomers), monoethyldiethanolamine, monoethyldipropanolamine (including all isomers) Including), monoethyldibutanolamine (including all isomers), mono Ethyldipentanolamine (including all isomers), monopropyldiethanolamine (including all isomers), monopropyldipropanolamine (including all isomers), monopropyldibutanolamine (all isomers) ), Monopropyldipentanolamine (including all isomers), monobutyldiethanolamine (including all isomers), monobutyldipropanolamine (including all isomers), monobutyldibutanolamine (Including all isomers), monobutyldipentanolamine (including all isomers), monocyclohexyl monoethanolamine, monocyclohexyl diethanolamine, monocyclohexyl monopropanolamine (including all isomers), monocyclohexyl Dipropanolamine (all It includes the including isomers) or the like.

  When such an amine is blended, a salt of an acidic phosphate ester and an amine can be formed, but in the present invention, these two components may be present as an amine salt in the lubricating oil composition. However, from the viewpoint of sliding properties, acidic phosphate ester itself is preferable to amine salt of acidic phosphate ester. Accordingly, the amine content is preferably 50 mol% or less, more preferably 30 mol% or less, still more preferably 10 mol% or less, and even more preferably 5 mol% with respect to the acidic phosphate ester. The following is more preferable, and it is particularly preferable that no amine is contained.

  The lubricating oil composition of the present invention is also used in a form in which various other additives are blended in order to further enhance its excellent properties as required. Such additives include phenolic compounds such as di-tert-butyl-p-cresol and bisphenol A, and amines such as phenyl-α-naphthylamine and N, N′-di (2-naphthyl) -p-phenylenediamine. Antioxidants such as compounds; Metal deactivators such as benzotriazole and alkylthiadiazole; Antifoaming agents such as silicone oil and fluorosilicone oil; Phosphorous additives other than acidic phosphates (regular phosphate ester, phosphorous acid) Acid esters, etc .; oily agents such as carboxylic acids; rust inhibitors such as alkenyl succinic acid and sorbitan monooleate; pour point depressants such as polymethacrylates; polymethacrylates, polybutenes, polyalkylstyrenes, olefin copolymers, styrene-dienes Viscosity of copolymer, styrene-maleic anhydride copolymer, etc. And the like index improver.

  The lubricating oil composition of the present invention having the above-described configuration can achieve all of the anti-stick-slip properties, friction properties and separability from water-soluble cutting fluid at a high level in a balanced manner. It is preferably used in various applications. In particular, the effect of the present invention is further exhibited when used as a lubricant for a sliding guide surface (sliding surface) of a machine tool or the like.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example at all.

[Examples 1-9, Comparative Examples 1-7]
In Examples 1-9 and Comparative Examples 1-7, lubricating oil compositions having the compositions shown in Tables 1 and 2 were prepared using the base oils and additives shown below, respectively.

(Base oil)
Base oil 1: Paraffin-based highly solvent refined base oil (kinematic viscosity at 40 ° C .: 65.5 mm ² / s)
(Phosphorus compound)
A1: oleyl acid phosphate A2: oleylamine salt of 2-ethylhexyl acid phosphate A3: 2-ethylhexyl acid phosphate A4: tricresyl phosphate (fatty acid)
B1: Capric acid B2: Lauric acid B3: Myristic acid B4: Palmitic acid B5: Stearic acid B6: Oleic acid (sulfur compound)
C1: sulfurized ester (sulfur content: 11.4% by mass)
C2: Sulfurized lard (sulfur content: 11.0% by mass)
(Polyalkylene glycol derivative)
D1: Polyalkylene glycol derivative represented by the following formula H— (EO) ₃ — (PO) _m — (EO) _n —H
(Average molecular weight: 3500, (1 + n) / (1 + m + n) = 0.1).

  Next, the following tests were performed on the lubricating oil compositions of Examples 1 to 9 and Comparative Examples 1 to 7.

(Frictional property evaluation test)
FIG. 1 is a schematic configuration diagram showing a friction coefficient measurement system used in a friction characteristic evaluation test. In FIG. 1, a table 1 and a movable jig 4 connected via a load cell 5 are arranged on a bed 6, and a heavyweight 9 as a substitute for a processing tool is arranged on the table 1. Yes. Both the table 1 and the bed 6 are made of cast iron. The movable jig 4 has a bearing portion, and the bearing portion is connected to the A / C servo motor 2 via the feed screw 3. By operating the feed screw 3 by the A / C servometer 2, the movable jig 4 can be reciprocated in the axial direction of the feed screw 3 (arrow direction in the figure). Further, the load cell 5 is electrically connected to the computer 7, and the computer 7 and the A / C servometer 2 are electrically connected to the control plate 8, thereby controlling the reciprocating motion of the movable jig 4 and the table 1 and the movable jig. The load between 4 can be measured.

  In such a friction coefficient measurement system, a lubricating oil composition is dropped on the upper surface of the bed 6, and after adjusting the surface pressure between the table 1 and the bed 6 to 200 kPa by selecting the table weight 9, the feed rate is 1.2 mm. The movable jig 4 was reciprocated with a feed length of 15 mm / min. The load between the table 1 and the movable jig 4 at this time is measured by a load cell 5 (load meter), and the friction coefficient of the guide surface (table 1 / bed 6 = cast iron / cast iron) based on the obtained measurement value. Asked. In addition, the said test was done after running in 3 times. The friction coefficient of each lubricating oil composition is shown in Tables 1 and 2.

(Stick-slip prevention evaluation test)
FIG. 2 is a schematic configuration diagram showing a stick-slip prevention evaluation device (TE-77 tester manufactured by Print & Partners). In the apparatus shown in FIG. 2, a lower test piece 12, an upper test piece 11, and an elastic body 10 are laminated in this order on a support base 110, and the elastic body 10 is pressed while pressing the test pieces 11 and 12 together with a predetermined load. The test pieces 11 and 12 are slid by reciprocating (sliding) along the surface of the support table 110. And the friction coefficient between the test pieces 11 and 12 is calculated | required by measuring the load added to the test pieces 11 and 12 by the load detector 13 in the case of this sliding. FIG. 3 is a graph showing an example of the correlation between the friction coefficient obtained by the above operation and time. Δμ in the figure indicates the amplitude of the friction coefficient.

  In accordance with the method described in the literature (Tribology Society Tribology Conference Proceedings Tokyo 1999-5 D17) except that the test piece and conditions were improved for the evaluation of the lubricating oil for the sliding guide surface using such an apparatus. Δμ when each lubricating oil composition was interposed between the test pieces 11 and 12 was measured. Specifically, JIS G 4051 S45C was used for each of the test pieces 11 and 12, chloroprene rubber was used for the elastic body 10, and the test was performed at an average sliding speed of 0.3 mm / s and a load of 250N. The stick-slip prevention property was evaluated as “no stick slip” when Δμ was less than 0.02, and “with stick slip” when the amplitude Δμ was 0.02 or more. The obtained results are shown in Tables 1 and 2.

(Evaluation test for separability from water-soluble cutting fluid)
100 mL graduated cylinder with 20 mL of lubricating oil composition and 80 mL of water-soluble cutting fluid (emulsion-type cutting fluid, manufactured by Nippon Oil Corporation, JISK 2241 “Cutting fluid” equivalent to W1 type No. 1, diluted 10 times) Collected. The measuring cylinder was capped and shaken at room temperature for 1 minute, and then the separation state was observed after 0.5 hours, 1 hour, 3 hours, 6 hours, and 24 hours, and the separation was evaluated. Evaluation of separability was performed as follows.

  FIG. 4 is an explanatory diagram showing an example of a separation state in the graduated cylinder 15 when a predetermined time has elapsed after shaking. In this test, the names of the separated layers are defined as a foam layer (F layer) 16, an oil layer (O layer) 17, a cream layer (C layer) 18, and an emulsified layer (E layer) 19 in the order from the stopper 14. The volume of each layer was measured. The obtained results are shown in Tables 1 and 2. The numerical values shown in the table indicate the volume of F layer-O layer-C layer-E layer, for example, "0-20-0-80" is 0 ml for F layer, 20 ml for O layer, 0 ml for C layer, It means that the E layer was 80 ml. In addition, the smaller the volume of the C layer or the shorter the time until the volume of the C layer becomes 0 ml, the better the separability.

(Low temperature storage stability test)
A cycle in which 500 ml of each lubricating oil composition is collected in a glass beaker and placed in a temperature-adjustable container, and mode A (0 ° C., 12 hours) and mode B (20 ° C., 12 hours) are alternately repeated. Drove. The appearance of each lubricating oil composition after 30 days was visually observed, and the low-temperature storage stability was evaluated by the presence or absence of precipitates or precipitates. The obtained results are shown in Tables 1 and 2.

表１及び表２に示した結果から明らかなように、実施例１〜９の潤滑油組成物は、比較例１〜７の組成物に比較して、摩擦係数が低く、またΔμが小さいことからスティックスリップ防止性にも優れ、さらに水溶性切削液分離試験後のクリーム層の体積が小さく、水溶性切削液との分離性に大きく優れるという良好な性能を兼ね備えていることがわかる。

As is clear from the results shown in Tables 1 and 2, the lubricating oil compositions of Examples 1 to 9 have a lower coefficient of friction and a smaller Δμ than the compositions of Comparative Examples 1 to 7. Therefore, it can be seen that it has excellent performance such as excellent anti-stick-slip property, and further has a small volume of the cream layer after the water-soluble cutting fluid separation test, and is excellent in separability from the water-soluble cutting fluid.

It is a schematic block diagram which shows the friction coefficient measuring system used in the Example. It is a schematic block diagram which shows the stick-slip prevention evaluation apparatus used in the Example. It is a graph which shows an example of the correlation with the friction coefficient obtained using the apparatus of FIG. 2, and time. It is explanatory drawing which shows the isolation | separation condition of each layer in the evaluation test of the separability with respect to a water-soluble cutting fluid.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Table, 2 ... A / C servo meter, 3 ... Feed screw, 4 ... Movable jig, 5 ... Load cell, 6 ... Bed, 7 ... Computer, 8 ... Control panel, 9 ... Heavyweight, 10 ... Elastic body, 11 ... Upper test piece, 12 ... Lower test piece, 13 ... Load detector, 110 ... Support base, 14 ... Plug, 15 ... Measuring cylinder, 16 ... Foam layer (F layer), 17 ... Oil layer (O layer), 18 ... Cream layer (C layer), 19 ... Emulsion layer (E layer).

Claims (4)

At least one base oil selected from mineral oils, fats and oils, and synthetic oils;
An acidic phosphate ester;
A saturated fatty acid having 12 to 14 carbon atoms;
A lubricating oil composition comprising: The lubricating oil composition according to claim 1, further comprising a sulfur-based extreme pressure agent. The lubricating oil composition according to claim 1 or 2, wherein the lubricating oil composition is a sliding guide surface lubricating oil composition. It further contains a saturated fatty acid having 16 carbon atoms, and the ratio of the saturated fatty acid having 16 carbon atoms to the total amount of the saturated fatty acid having 12 to 14 carbon atoms and the saturated fatty acid having 16 carbon atoms is 50% by mass or less. The lubricating oil composition according to any one of claims 1 to 3.

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