JP6235864B2 - Lubricating oil composition - Google Patents

Description

  The present invention relates to a lubricating oil composition, and more particularly to a lubricating oil composition suitable as a speed increasing oil composition for wind power generation.

From the viewpoint of reducing environmental impacts in recent years and the depletion of fossil fuels, wind power generation using renewable energy is expected to increase further in the future.
Wind power generation using wind power uses a propeller or other rotor that rotates in response to wind to convert wind kinetic energy into power, which drives the generator to convert it into electrical energy.
In such wind power generation, since the rotational speed of the rotor is slow, a speed increaser is used in consideration of the power generation efficiency of the generator. Various types of speed increasers are known, and planetary gear type power transmission devices are frequently used.

It is required that the speed-up gear oil composition for wind power generation used in such a planetary gear type power transmission device can be operated without maintenance for a long period of time.
As a lubricating oil composition used for a wind power booster, in the example of Patent Document 1, a composition containing a poly α-olefin and a polyol ester is disclosed.

WO2008 / 038701

However, as a result of extensive research by the present inventors, seizure due to foaming may occur when a lubricating oil composition containing a poly-α-olefin and an ester base oil is used in a wind power booster oil application. I found out. Furthermore, even when an antifoaming agent is added in order to suppress foaming, it has been found that the defoaming performance is greatly deteriorated during long-term operation depending on the type of antifoaming agent.
An object of the present invention is to provide a lubricating oil composition suitable as a speed increasing oil composition for wind power generation while maintaining excellent defoaming performance for a long time under such circumstances.

As a result of intensive studies to develop the lubricating oil composition having the above-mentioned excellent performance, the present inventor has (A) a poly α-olefin base oil, (B) an ester base oil, and (C) an ester. It has been found that the above problem can be solved by a combination of the antifoaming agents. The present invention has been completed based on such findings.
That is, the present invention
[1] A lubricating oil composition comprising (A) 70 to 95% by mass of a poly α-olefin base oil, (B) 5 to 20% by mass of an ester base oil, and (C) an ester defoamer. And (A) the poly α-olefin base oil is an α-olefin polymer having 8 to 12 carbon atoms,
[2] The lubricating oil composition according to [1], wherein the total amount of the (A) poly α-olefin base oil and the (B) ester base oil is 90% by mass or more based on the total amount of the composition,
[3] The lubricating oil composition according to [1] or [1], wherein the (C) ester-based antifoaming agent comprises a (meth) acrylate polymer having a weight average molecular weight of 10,000 to 100,000.
[4] The lubricating oil composition according to any one of [1] to [3], wherein the (A) poly α-olefin base oil is a decene oligomer.
[5] The lubricating oil composition according to any one of [1] to [4], in which the (B) ester base oil is a polyol ester, and [6] a step-up gear oil composition for wind power generation [ 1] to [5], a lubricating oil composition according to any one of
Is to provide.

  ADVANTAGE OF THE INVENTION According to this invention, the outstanding defoaming performance can be maintained for a long period of time, and the lubricating oil composition suitable as a gearbox oil composition for wind power generation can be provided.

  The lubricating oil composition of the present invention contains (A) a poly α-olefin base oil 70 to 95% by mass, (B) an ester base oil 5 to 20% by mass, and (C) an ester defoamer. To do.

[(A) Poly α-olefin base oil]
The (A) poly α-olefin base oil is a polymer obtained by using one or more α-olefins having 8 to 12 carbon atoms.
(A) As a poly alpha olefin base oil, a 40 degreeC kinematic viscosity is in the range of 30-800 mm < ² > / s, and a viscosity index is 80 or more is suitable. If the kinematic viscosity at 40 ° C. is 30 mm ² / s or more, the evaporation loss is small. On the other hand, if it is 800 mm ² / s or less, the power loss due to viscous resistance does not become so large. More preferably 40 ° C. kinematic viscosity is 32~680mm ² / s, it is preferable in particular 100 to 500 mm ² / s. If the viscosity index is 80 or more, the change in viscosity due to the change in temperature is small. This viscosity index is more preferably 100 or more, and still more preferably 130 or more.
The (A) poly α-olefin base oil preferably has a pour point of −25 ° C. or lower. If the pour point is −25 ° C. or less, the lubricating oil composition of the present invention containing the pour point has sufficient fluidity even in a low temperature environment. (A) The pour point of the poly α-olefin base oil is more preferably −30 ° C. or lower, and further preferably −40 ° C. or lower.
The kinematic viscosity and the viscosity index are values measured according to JIS K 2283, and the pour point is a value measured according to JIS K 2265.

  The content of the (A) poly α-olefin base oil in the lubricating oil composition of the present invention is 70 to 95% by mass, preferably 75 to 95% by mass, and preferably 80 to 92% based on the total amount of the composition. More preferably, it is mass%. (A) When the content of the poly α-olefin base oil is less than 70% by mass, the high seizure resistance and fatigue resistance required for a wind power booster oil cannot be obtained, and the antifoaming property is not obtained. When it is insufficient and exceeds 95% by mass, the content of the (B) ester base oil becomes insufficient.

[(B) Ester base oil]
As the (B) ester base oil, a polyol ester is preferably used, which may be a partial ester or a complete ester of a polyol, but using a partial ester of a polyol is from the viewpoint of sludge solubility. preferable.
The polyol used as a raw material for the polyol ester is not particularly limited, but is preferably an aliphatic polyol. Examples of the polyol include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol, and neopentyl glycol. Examples thereof include trihydric alcohols such as dihydric alcohol, glycerin, trimethylolethane, and trimethylolpropane, and polyhydric alcohols such as diglycerin, triglycerin, pentaerythritol, dipentaerythritol, mannitol, and sorbit.

The hydrocarbyl group constituting the polyol ester is preferably an alkyl group or alkenyl group having 6 to 30 carbon atoms, more preferably an alkyl group or alkenyl group having 12 to 24 carbon atoms, such as various hexyl groups, octyl groups, Examples include decyl, dodecyl, tetradecyl, hexadecyl, heptadecyl, octadecyl, hexenyl, octenyl, decenyl, dodecenyl, tetradecenyl, hexadecenyl, octadecenyl and the like.
The alkyl group or alkenyl group may be linear or branched.

  Specific examples of the complete ester of polyol include neopentyl glycol dilaurate, neopentyl glycol dimyristate, neopentyl glycol dipalmitate, neopentyl glycol distearate, neopentyl glycol diisostearate, trimethylolpropane trilaurate. , Trimethylolpropane trimyristate, trimethylolpropane tripalmitate, trimethylolpropane tristearate, trimethylolpropane triisostearate, glycerol trilaurate, glycerol tristearate, glycerol triisostearate, etc. However, it is not limited to these.

The partial ester of polyol is not particularly limited as long as at least one hydroxyl group remains.
Specific examples of the partial ester of the polyol include neopentyl glycol monolaurate, neopentyl glycol monomyristate, neopentyl glycol monopalmitate, neopentyl glycol monostearate, neopentyl glycol monoisostearate, trimethylolpropane. Mono or dilaurate, trimethylolpropane mono or dimyristate, trimethylolpropane mono or dipalmitate, trimethylolpropane mono or distearate, trimethylolpropane mono or diisostearate, glycerol mono or dilaurate, glycerol mono or distearate, glycerol mono or diiso Although a stearate etc. can be mentioned, it is not limited to these.

As said polyol ester, what is represented by the following general formula (B-1) is preferable from viewpoints, such as foaming prevention property.
(R ¹ —COO—) _n L (B-1)
(In the formula, R ¹ is a hydrocarbon group having 6 to 30 carbon atoms, n is an integer of 2 to 4, and L is an n-valent hydrocarbon group.)
R ¹ is preferably an alkyl group or alkenyl group having 12 to 24 carbon atoms.
n is preferably 3 or 4.
L is preferably an n-valent hydrocarbon group having 3 to 10 carbon atoms.

  In the lubricating oil composition of the present invention, as the (B) ester base oil, a polyol ester may be used alone, or two or more kinds may be used in combination. Moreover, the compounding quantity is 5-20 mass% on the basis of the composition whole quantity, Preferably it is 7-15 mass%. (B) When content of ester base oil is less than 5 mass%, sludge solubility becomes inadequate and the solubility of an additive becomes inadequate.

  In the lubricating oil composition of the present invention, the total amount of the (A) poly-α-olefin base oil and the (B) ester base oil may be 90% by mass or more based on the total amount of the composition. Preferably, it is 92-99 mass%, More preferably, it is 93-98 mass%.

[Other base oils]
The lubricating oil composition of the present invention may contain a base oil other than the above-mentioned (A) poly α-olefin base oil and (B) ester base oil, but the content is based on the total amount of the composition. It is less than 25% by mass, preferably 15% by mass or less, and more preferably 10% by mass or less.
There is no restriction | limiting in particular as another base oil, Both mineral oil and synthetic oil can be used. Here, as the mineral oil, various conventionally known oils can be used, for example, paraffin-based mineral oil, intermediate-based mineral oil, naphthene-based mineral oil, and the like. Specific examples include solvent refining or hydrogen refining. Light neutral oil, medium neutral oil, heavy neutral oil, bright stock, etc. can be mentioned.
As the synthetic oil, various conventionally known oils can be used. For example, polybutene, phosphate ester, polyphenyl ether, alkylbenzene, alkylnaphthalene, polyoxyalkylene glycol, neopentyl glycol, silicone oil, Methylolpropane, pentaerythritol, hindered ester, etc. can be used. These base oils can be used alone or in combination of two or more kinds, and mineral oil and synthetic oil may be used in combination.

[(C) Ester-based antifoaming agent]
(C) As an ester type antifoamer, what consists of (meth) acrylate polymer is preferable.
The (meth) acrylate polymer preferably has a weight average molecular weight of 10,000 to 100,000.

[(D) sulfur compound]
The lubricating oil composition of the present invention may further contain (D) a sulfur compound.
(D) As a specific example of the sulfur compound, (d-1) sulfur containing no -S-S-S- or higher polysulfur bond in the molecule and having an S content of 15% by mass or more in the molecule And (d-2) thiophosphoric acid trihydrocarbyl esters represented by the following general formula (I).
(R—O—) ₃ P = S (I)
(In the formula, R represents a hydrocarbyl group having 6 to 20 carbon atoms.)

As a sulfur compound of the said (d-1) component, the following compound can be mentioned, for example.
(1) Mono- or disulfide olefins (2) Dihydrocarbyl mono- or disulfide (3) Thiadiazole compounds (4) Dithiocarbamate compounds (5) Ester compounds having a disulfide structure (6) Other sulfur compounds

[Mono or disulfide olefin]
Examples of the sulfurized olefin include compounds represented by the following general formula (III).
R ¹ -S _a -R ² (III)
(In the formula, R ¹ represents an alkenyl group having 2 to 15 carbon atoms, R ² represents an alkyl group or alkenyl group having 2 to 15 carbon atoms, and a represents 1 or 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. As the olefin, propylene, isobutene, diisobutene and the like are preferable.

[Dihydrocarbyl mono or disulfide]
Examples of dihydrocarbyl mono or disulfide include compounds represented by the following general formula (IV).
R ³ -S _b -R ⁴ (IV)
(In the formula, R ³ and R ⁴ are each an alkyl group having 1 to 20 carbon atoms or a cyclic alkyl group, an aryl group having 6 to 20 carbon atoms, an alkylaryl group having 7 to 20 carbon atoms, or 7 to 20 carbon atoms. An arylalkyl group, which may be the same or different from each other, and b represents 1 or 2)
Here, the compound represented by the general formula (IV) is referred to as alkyl sulfide when R ³ and R ⁴ are alkyl groups.
Examples of the dihydrocarbyl mono or disulfide represented by the general formula (IV) include, for example, dibenzyl mono or disulfide, various dinonyl mono or disulfide, various didodecyl mono or disulfide, various dibutyl mono or disulfide, various dioctyl mono or disulfide. , Diphenyl mono or disulfide, dicyclohexyl mono or disulfide and the like can be preferably exemplified.

[Thiadiazole compounds]
Examples of 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, 3,6-bis (n-octyldithio) -1,2,4-thiadiazole, 3,5-bis (n-nonyldithio) -1,2,4 -Thiadiazole, 3,5-bis (1,1,3,3-tetramethylbutyldithio) -1,2,4-thiadiazole, 4,5-bis (n-octyldithio) -1,2,3-thiadiazole 4,5-bis n- nonyldithio) -1,2,3-thiadiazole, 4,5-bis (1,1,3,3-tetramethylbutyl dithio) -1,2,3-thiadiazoles such as can be a preferably exemplified.

[Dithiocarbamate compound]
Examples of the dithiocarbamate compound include alkylene bisdialkyldithiocarbamate, among which an alkylene group having 1 to 3 carbon atoms, a linear or branched saturated or unsaturated alkyl group having 3 to 20 carbon atoms, or a carbon number A compound having a cyclic alkyl group of 6 to 20 is preferably used. Specific examples of such dithiocarbamate compounds include methylene bisdibutyl dithiocarbamate, methylene bisdioctyl dithiocarbamate, methylene bistridecyl dithiocarbamate, and the like.

[Ester compound having a disulfide structure]
As the ester compound having a disulfide structure, a disulfide compound represented by the general formula (V) and a disulfide compound represented by the general formula (VI) are used.
^{R 5 OOC-A 1 -S-} S-A 2 -COOR 6 ··· (V)
^{R 11 OOC-CR 13 R 14} -CR 15 (COOR 12) -S-S-R 20 (COOR 17) -CR 18 R 19 -COOR 16 ··· (VI)
In the general formula (V), R ⁵ and R ⁶ are each independently a hydrocarbyl group having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms, more preferably 2 to 18 carbon atoms, and particularly preferably carbon number. 3 to 18 hydrocarbyl groups. The hydrocarbyl group may be linear, branched or cyclic, and may contain an oxygen atom, a sulfur atom or a nitrogen atom. R ⁵ and R ⁶ may be the same or different, but are preferably the same for manufacturing reasons.
Next, A ¹ and A ² are each independently a group represented by CR ⁷ R ⁸ or CR ⁷ R ⁸ —CR ⁹ R ¹⁰ , and R ^{7 to} R ¹⁰ are each independently a hydrogen atom or a carbon number. 1-20 hydrocarbyl groups. The hydrocarbyl group preferably has 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms. A ¹ and A ² may be the same or different from each other, but are preferably the same for manufacturing reasons.

On the other hand, in the general formula (VI), R ¹¹ , R ¹² , R ¹⁶ and R ¹⁷ are each independently a hydrocarbyl group having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms, more preferably 2 to 2 carbon atoms. A hydrocarbyl group having 18, especially 3 to 18 carbon atoms is preferred. The hydrocarbyl group may be linear, branched or cyclic, and may contain an oxygen atom, a sulfur atom or a nitrogen atom. R ¹¹ , R ¹² , R ¹⁶ and R ¹⁷ may be the same or different from each other, but are preferably the same for reasons of production.
Next, R ^{13 to} R ¹⁵ and R ^{18 to} R ²⁰ are each independently a hydrogen atom or a hydrocarbyl group having 1 to 5 carbon atoms. A hydrogen atom is preferable because the raw material is easily available.

  Specific examples of the disulfide compound represented by the general formula (V) include bis (methoxycarbonylmethyl) disulfide, bis (ethoxycarbonylmethyl) disulfide, bis (n-propoxycarbonylmethyl) disulfide, bis (isopropoxycarbonylmethyl). ) Disulfide, bis (cyclopropoxycarbonylmethyl) disulfide, 1,1-bis (1-methoxycarbonylethyl) disulfide, 1,1-bis (1-methoxycarbonyl-n-propyl) disulfide, 1,1-bis (1 -Methoxycarbonyl-n-butyl) disulfide, 1,1-bis (1-methoxycarbonyl-n-hexyl) disulfide, 1,1-bis (1-methoxycarbonyl-n-octyl) disulfide, 2,2-bis ( 2-methoxycarbonyl -N-propyl) disulfide, α, α-bis (α-methoxycarbonylbenzyl) disulfide, 1,1-bis (2-methoxycarbonylethyl) disulfide, 1,1-bis (2-ethoxycarbonylethyl) disulfide, , 1-bis (2-n-propoxycarbonylethyl) disulfide, 1,1-bis (2-isopropoxycarbonylethyl) disulfide, 1,1-bis (2-cyclopropoxycarbonylethyl) disulfide, 1,1-bis (2-methoxycarbonyl-n-propyl) disulfide, 1,1-bis (2-methoxycarbonyl-n-butyl) disulfide, 1,1-bis (2-methoxycarbonyl-n-hexyl) disulfide, 1,1- Bis (2-methoxycarbonyl-n-propyl) disulfide, 2, - bis (3-methoxycarbonyl -n- pentyl) disulfide, 1,1-bis (2-methoxycarbonyl-1-phenylethyl) and the like disulfides.

  Specific examples of the disulfide compound represented by the general formula (VI) include tetramethyl dithiomalate, tetraethyl dithiomalate, tetra-1-propyl dithiomalate, tetra-2-propyl dithiomalate, and tetra-1-butyl dithiomalate. , Tetra-2-butyl dithiomalate, tetraisobutyl dithiomalate, tetra-1-hexyl dithiomalate, tetra-1-octyl dithiomalate, tetra-1- (2-ethyl) hexyl dithiomalate, tetra-1-dithiomalate 3,5,5-trimethyl) hexyl, tetra-1-decyl dithiomalate, tetra-1-dodecyl dithiomalate, tetra-1-hexadecyl dithiomalate, tetra-1-octadecyl dithiomalate, tetrabenzyl dithiomalate, dithioline Tetra-α- (methyl) benzyl acid, tetra-α, α-dimethylbenzyl dithiomalate, tetra-1- (2-methoxy) ethyl dithiomalate, tetra-1- (2-ethoxy) ethyl dithiomalate, tetra-dithiomalate 1- (2-butoxy) ethyl, tetra-1- (2-ethoxy) ethyl dithiomalate, tetra-1- (2-butoxy-butoxy) ethyl dithiomalate, tetra-1- (2-phenoxy) ethyl dithiomalate, etc. Can be mentioned.

[Other sulfur compounds]
Examples of other sulfur compounds include sulfurized fats such as sulfurized lard, sulfurized rapeseed oil, sulfurized castor oil, sulfurized soybean oil and sulfurized rice bran oil, sulfurized fatty acids such as thioglycolic acid and sulfurized oleic acid, dilauryl thiodipropionate, and distearyl. Examples thereof include dialkylthiodipropionate compounds such as thiodipropionate and dimyristylthiodipropionate, and thioterpene compounds obtained by reacting phosphorus pentasulfide with pinene.

  In the lubricating oil composition of the present invention, as the sulfur compound of component (d-1), the aforementioned sulfur compounds may be used alone or in combination of two or more. In addition, the blending amount of the component (d-1) is preferably 0.2 to 0.6% by mass as a sulfur atom based on the total amount of the lubricating oil composition, and is preferably 0.3 to 0.5% by mass. % Is more preferable. When the sulfur atom content is 0.2% by mass or more, seizure resistance is improved, and when it is 0.6% by mass or less, fatigue resistance is improved and generation of sludge is suppressed.

The lubricating oil composition of the present invention may optionally contain a thiophosphate trihydrocarbyl ester represented by the general formula (I) as the component (d-2).
(R—O—) ₃ P = S (I)
R in the general formula (I) represents a hydrocarbyl group having 6 to 20 carbon atoms. The hydrocarbyl group is a linear, branched, or cyclic alkyl group or alkenyl group having 6 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms. In the aryl group and aralkyl group, one or more alkyl groups may be introduced on the aromatic ring. Further, the three R—O— groups may be the same or different.
Examples of the alkyl group and alkenyl group having 6 to 20 carbon atoms include various hexyl groups, various octyl groups, various decyl groups, various dodecyl groups, various tetradecyl groups, various hexadecyl groups, various octadecyl groups, cyclohexyl groups, and various hexenyl groups. And various octenyl groups, various decenyl groups, various dodecenyl groups, various tetradecenyl groups, various hexadecenyl groups, various octadecenyl groups, and cyclohexenyl groups.
Examples of the aryl group having 6 to 20 carbon atoms include phenyl group, tolyl group, xylyl group, decylphenyl group, 2,4-didecylphenyl group, naphthyl group and the like, and examples of the aralkyl group having 7 to 20 carbon atoms include Examples include benzyl group, phenethyl group, naphthylmethyl group, methylbenzyl group, methylphenethyl group, and methylnaphthylmethyl group.
Specific examples of the thiophosphoric acid trihydrocarbyl esters represented by the general formula (I) include trihexyl thiophosphate, tri-2-ethylhexyl thiophosphate, tris (decyl) thiophosphate, trilauryl thiophosphate, trimyristylthio. Phosphate, tripalmityl thiophosphate, tristearyl thiophosphate, trioleyl thiophosphate, tricresyl thiophosphate, trixylyl thiophosphate, tris (decylphenyl) thiophosphate, tris [2,4-isoalkyl (C ₉ , C ₁₀ ) Phenyl] thiophosphate and the like. One of these thiophosphate trihydrocarbyl phosphates may be used alone, or two or more thereof may be used in combination.
In the lubricating oil composition of the present invention, the thiophosphoric acid trihydrocarbyl ester of the component (d-2) is added as desired in order to further enhance the effect of adding the sulfur compound of the component (d-1). The amount added is preferably in the range of 0.1 to 1.0% by mass, more preferably 0.2 to 0.5% by mass, based on the total amount of the lubricating oil composition. Moreover, it is preferable that content of all the phosphorus atoms in a lubricating oil composition is 150-500 mass ppm.

[(E) Acid phosphate ester amine salt]
The lubricating oil composition of the present invention preferably further contains (E) an acidic phosphate ester amine salt.
(E) The acidic phosphoric acid ester amine salt includes (e-1) an acidic phosphoric acid alkyl ester having 6 to 20 carbon atoms in the alkyl group, and (e-2) a dialkylamine and / or a trialkylamine. Those obtained by reacting in advance may be blended, or may be incorporated into the lubricating oil composition of the present invention by blending them.

[(E-1) Acidic alkyl phosphate esters]
As said (e-1) acidic phosphoric acid alkylester, what is represented by the following general formula (II) is preferable.

X ¹ in the general formula (II) represents a hydrogen atom or an alkyl group having 6 to 20 carbon atoms, and X ² represents an alkyl group having 6 to 20 carbon atoms.
The alkyl group having 6 to 20 carbon atoms may be linear, branched or cyclic, and examples thereof include various hexyl groups, octyl groups, decyl groups, dodecyl groups, tetradecyl groups, hexadecyl groups, An octadecyl group, an icosyl group, etc. are mentioned. Among these, an alkyl group having 10 to 18 carbon atoms is preferable.
Examples of the acidic phosphoric acid alkyl esters represented by the general formula (II) include monooctyl acid phosphate, monodecyl acid phosphate, monoisodecyl acid phosphate, monolauryl acid phosphate, mono (tridecyl) acid phosphate, and monomyristyl. Acid phosphate monoester, monopalmityl acid phosphate, monostearyl acid phosphate monophosphate, dioctyl acid phosphate, didecyl acid phosphate, diisodecyl acid phosphate, dilauryl acid phosphate, di (tridecyl) acid phosphate, dipalmityl acid Examples thereof include acidic phosphoric acid diesters such as phosphate and distearyl acid phosphate.

  In this invention, as said (e-1) component, the said acidic phosphate ester may be used individually by 1 type, and may be used in combination of 2 or more type. Moreover, it is preferable that the compounding quantity is 150-500 mass ppm by content of all the phosphorus atoms in a lubricating oil composition. When the phosphorus atom content is 150 mass ppm or more, seizure resistance is improved, and when it is 500 mass ppm or less, fatigue resistance is improved. A more preferable phosphorus atom content is 250 to 450 mass ppm, and further preferably 350 to 400 mass ppm.

[(E-2) Dialkylamines and / or trialkylamines]
As the dialkylamines and / or trialkylamines used as the component (e-2), those having 6 to 20 carbon atoms in the alkyl group are preferable.
Examples of dialkylamines include dihexylamine, dicyclohexylamine, dioctylamine, dilaurylamine, distearylamine, and examples of trialkylamines include trihexylamine, tricyclohexylamine, and trioctylamine. , Trilaurylamine, tristearylamine and the like.
In the lubricating oil composition of the present invention, as the component (e-2), the dialkylamines and trialkylamines may be used singly or in combination of two or more. Among them, trialkylamines are preferable from the viewpoint of performance. In addition, seizure resistance is reduced with monoalkylamines.

  In the lubricating oil composition of the present invention, various additives such as an ashless detergent dispersant, an antioxidant, a rust inhibitor, a metal deactivator and a fluid are used as long as the object of the present invention is not impaired. At least one selected from point depressants and the like can be blended.

  Examples of the ashless detergent / dispersant include mono- or divalent succinic imides, boron-containing succinimides, benzylamines, boron-containing benzylamines, succinic esters, fatty acids or succinic acids. And carboxylic acid amides.

  As the antioxidant, amine-based antioxidants, phenol-based antioxidants and sulfur-based antioxidants conventionally used in lubricating oils can be used. These antioxidants can be used singly or in combination of two or more. Examples of the amine antioxidant include monoalkyl diphenylamine compounds such as monooctyl diphenylamine and monononyl diphenylamine, 4,4′-dibutyldiphenylamine, 4,4′-dipentyldiphenylamine, 4,4′-dihexyldiphenylamine, 4 , 4′-diheptyldiphenylamine, 4,4′-dioctyldiphenylamine, dialkyldiphenylamine compounds such as 4,4′-dinonyldiphenylamine, polyalkyl such as tetrabutyldiphenylamine, tetrahexyldiphenylamine, tetraoctyldiphenylamine, tetranonyldiphenylamine Diphenylamine compounds, α-naphthylamine, phenyl-α-naphthylamine, butylphenyl-α-naphthylamine, pentylphenyl α- naphthylamine, hexylphenyl -α- naphthylamine, heptylphenyl -α- naphthylamine, octylphenyl -α- naphthylamine, and naphthylamine-based compounds such as nonylphenyl -α- naphthylamine.

Examples of the phenolic antioxidant include 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, and octadecyl 3- (3.5-di- monophenol compounds such as tert-butyl-4-hydroxyphenyl) propionate, 4,4′-methylenebis (2,6-di-tert-butylphenol), 2,2′-methylenebis (4-ethyl-6-tert- And diphenolic compounds such as butylphenol).
Examples of the sulfur-based antioxidant include 2,6-di-tert-butyl-4- (4,6-bis (octylthio) -1,3,5-triazin-2-ylamino) phenol, phosphorus pentasulfide and Examples thereof include thioterpene compounds such as a reaction product with pinene, and dialkylthiodipropionates such as dilauryl thiodipropionate and distearyl thiodipropionate.

Examples of the rust preventive agent include metal sulfonates and succinic acid esters, and examples of the metal deactivator include benzotriazole and thiadiazole.
As the pour point depressant, polymethacrylate having a weight average molecular weight of about 50,000 to 150,000 can be used.
The lubricating oil composition of the present invention is excellent in seizure resistance and fatigue resistance (FZG micropitting resistance, etc.) and generates little sludge in the oxidation test. For example, it is used as various lubricating oils such as gear oil and bearing oil. In particular, it is suitable as a lubricating oil used in a planetary gear type power transmission device used in a wind power generator.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
The properties of the base oil used in each example and various characteristics of the lubricating oil composition obtained in each example were determined according to the following methods.
<Properties of base oil>
(1) Kinematic viscosity, viscosity index Measured according to JIS K 2283.
(2) Foaming test In accordance with JIS K 2518, air blowing was started at 24 ° C., and the volume of the foam after 1 hour and after 10 hours was measured.
(3) Foaming test after filtration The lubricating oil composition was filtered using a 5 μm Millipore filter, and 300 ml of the filtrate was measured in a test tube for turbine oil oxidation stability test specified in JIS K2839. The volume of the foam in a state where air was blown at 3 L / h through a diffuser defined in K2518 was measured.

Moreover, the kind of each component used for preparation of a lubricating oil composition is as follows.
(A) Poly α-olefin base oil 1 (PAO base oil 1): Decene oligomer, 40 ° C. kinematic viscosity 390 mm ² / s, viscosity index 149, pour point −50 ° C. or less Poly α-olefin base oil 2 (PAO Base oil 2): Decene oligomer, 40 ° C. kinematic viscosity 46 mm ² / s, viscosity index 137, pour point −50 ° C. or less / Thickener 1: ethylene-propylene oligomer, weight average molecular weight (Mw) = 14,400
Thickener 2: Polybutene Thickener 3: Hydrogenated petroleum resin (B) Ester base oil: ester of trimethylolpropane and isostearic acid (molar ratio 1: 2)
(C) Ester-based antifoaming agent: 30 to 40% by mass of antifoaming component (weight average molecular weight: 50,000), mineral oil 60 to 70% by mass
・ Silicone-based antifoaming agent: 20 ° C. Refractive index: 1.405, flash point (COC): 370 ° C.
(D) Sulfur compound (d-1) Sulfur compound: Methylenebis (dibutyldithiocarbamate)
(D-2) sulfur compound: tris (isoalkylphenol) thiophosphate (manufactured by BASF, “IRGALUBE 211”)
(E) Acid phosphate ester amine salt (e-1) Acid phosphate alkyl ester: Acid phosphate (mono, di) isodecyl ester (mixing molar ratio of monoester to diester = 1: 1)
(E-2) Amines: Tri-n-octylamine

Example 1 and Comparative Examples 1 to 4
A lubricating oil composition having the composition shown in Table 1 was prepared and its foaming characteristics were determined. The results are shown in Table 1.

  Since the lubricating oil composition of the present invention can maintain excellent defoaming performance for a long period of time, it is particularly suitable as a lubricating oil used in a speed increaser such as a planetary gear type power transmission device used in a wind power generator. It is.

Claims (5)

A lubricating oil composition comprising (A) 70 to 95% by mass of a poly-α-olefin base oil, (B) 5 to 20% by mass of an ester-based base oil, and (C) an ester-based antifoaming agent, the (a) poly α- olefin base oil, Ri polymer der of α- olefin having 8 to 12 carbon atoms, the (C) an ester-based defoaming agent, a weight average molecular weight of 10,000 to 100,000 A lubricating oil composition comprising the (meth) acrylate polymer .   The lubricating oil composition according to claim 1, wherein the total amount of the (A) poly α-olefin base oil and the (B) ester base oil is 90% by mass or more based on the total amount of the composition. Wherein (A) poly α- olefin base oil, the lubricating oil composition according to claim 1 or 2 is a decene oligomer. The lubricating oil composition according to any one of claims 1 to 3 , wherein the ester base oil (B) is a polyol ester. The lubricating oil composition according to any one of claims 1 to 4 , which is a speed increasing oil composition for wind power generation.