JPWO2017150707A1 - Lubricating oil composition - Google Patents

Abstract

The lubricating oil composition of the present invention comprises, together with a base oil, an olefin oligomer (A) having a mass average molecular weight of 500 or more and 5000 or less, a phenolic antioxidant (B-1) and an amine antioxidant (B-2). Containing the antioxidant (B) and the alkaline earth metal detergent (C), and the alkaline earth metal atom (C) content in terms of alkaline earth metal atoms is the lubricating oil composition It is 1700 mass ppm or more and 2700 mass ppm or less on the basis of the total amount of the product, and the kinematic viscosity at 100 ° C. is 4.0 mm ² / s or more and 6.0 mm ² / s or less.

Description

  The present invention relates to a lubricating oil composition.

  The present invention relates to a lubricating oil composition, for example, a lubricating oil composition suitably used for a transmission.

In recent years, from the viewpoint of reducing carbon dioxide emissions and fossil fuel consumption, there has been a strong demand for fuel saving in automobiles. For example, in a lubricating oil for an automobile gear device, a reduction in viscosity is being promoted in order to reduce stirring resistance. However, lowering the viscosity of the lubricating oil lowers the oil film strength in the high temperature region, and there is a concern that seizure resistance, wear resistance, fatigue resistance, and the like may decrease. For this, it is effective to keep the viscosity of the lubricating oil high in the high temperature range and to reduce the viscosity of the lubricating oil in the normal temperature range. That is, increasing the viscosity index is effective.
However, to increase the viscosity index, it is necessary to add a viscosity index improver such as a polymer to the lubricating oil. These polymers cause a reduction in the viscosity of the lubricating oil by undergoing shear during use. Therefore, when blending the viscosity index improver with the lubricating oil, it is necessary to consider such a decrease in viscosity during actual vehicle travel.

In addition, transmission design is becoming smaller and lighter. As the transmission is reduced in size and weight, the mechanical load on the lubrication part increases, so that the lubricating oil to be filled is required to have further improved lubricity. Further, since the heat load increases, further improvement in the heat resistance and oxidation stability of the lubricating oil is required.
When the heat resistance and oxidation stability of the lubricating oil are deteriorated, sludge is generated, and this adheres to the lubrication site, resulting in poor lubrication. For example, a malfunction of a bearing or the like due to adhesion of sludge can be mentioned. Further, particularly in a manual transmission, the adhesion of sludge in the synchromesh mechanism responsible for shifting the gear position causes a reduction in shift feeling due to a reduction in friction characteristics, and further a malfunction due to the synchronizer ring being fixed.

In Patent Documents 1 and 2, by adding a viscosity index improver excellent in shear stability to a low-viscosity base oil, the viscosity of the lubricating oil is further reduced (kinematic viscosity at 100 ° C .: minimum 6.2 mm ² / s. ). However, since it is not possible to completely suppress the decrease in the viscosity of the lubricating oil due to actual vehicle travel, there is a limit to lowering the viscosity of the new oil.
In Patent Document 3, a molybdenum-based compound is used as a lubricating oil while reducing the viscosity without adding a polymethacrylate-based compound to the lubricating oil (kinematic viscosity at 100 ° C .: about 6.0 mm ² / s or more in the examples). By blending, the wear in the synchromesh is prevented and the friction characteristics are maintained.

JP 2012-193255 A JP 2014-177605 A JP 2014-98090 A

The techniques described in Patent Documents 1 to 3 do not solve the concern associated with the reduction in the viscosity of the lubricating oil. Further, it does not sufficiently satisfy the demand for improvement in heat resistance and oxidation stability accompanying reduction in size and weight of the apparatus.
The present invention has been made in view of the above circumstances. That is, an object of the present invention is to provide a lubricating oil composition that reduces viscosity during actual vehicle travel and achieves improved heat resistance and oxidation stability while achieving low viscosity.

As a result of intensive studies, the present inventors have found that a lubricating oil composition containing specific (A) to (C) components as essential components together with a base oil can solve the above-mentioned problems.
That is, the present invention provides the following [1] to [5].
[1] Along with the base oil,
Olefin oligomer (A) having a mass average molecular weight of 500 or more and 5000 or less,
Antioxidant (B) containing phenolic antioxidant (B-1) and amine antioxidant (B-2), and alkaline earth metal detergent (C)
Including
The content of the alkaline earth metal detergent (C) in terms of alkaline earth metal atoms is 1700 mass ppm or more and 2700 mass ppm or less based on the total amount of the lubricating oil composition,
A lubricating oil composition having a kinematic viscosity at 100 ° C. of 4.0 mm ² / s or more and 6.0 mm ² / s or less.
[2] A transmission filled with the lubricating oil composition according to [1].
[3] A lubricating method using the lubricating oil composition according to the above [1].
[4] A method for using the lubricating oil composition according to [1] in a transmission.
[5] An antioxidant (A) containing an olefin oligomer (A) having a mass average molecular weight of 500 or more and 5000 or less, a phenolic antioxidant (B-1) and an amine antioxidant (B-2) in the base oil. B), and a method for producing a lubricating oil composition comprising an alkaline earth metal detergent (C), wherein the alkaline earth metal detergent (C) is based on the total amount of the lubricating oil composition. The manufacturing method of the lubricating oil composition mix | blended so that content in conversion of alkaline-earth metal atom may be 1700 mass ppm or more and 2700 mass ppm or less.

  According to the present invention, it is possible to provide a lubricating oil composition that achieves low viscosity, suppresses a decrease in viscosity during actual vehicle travel, and achieves improved heat resistance and oxidation stability.

  Hereinafter, an embodiment of the present invention will be described in detail. In the present invention, “kinematic viscosity at 100 ° C.” and “kinematic viscosity at 40 ° C.” of the base oil or the lubricating oil composition mean values measured based on the method described in JIS K 2283: 2000.

  In the present invention, the content of the alkaline earth metal atom in the lubricating oil composition means a value measured according to JPI-5S-38-92.

  In the present invention, “alkaline earth metal atom” refers to a beryllium atom, a magnesium atom, a calcium atom, a strontium atom, and a barium atom.

The lubricating oil composition according to the present embodiment includes, together with a base oil, an olefin oligomer (A) having a mass average molecular weight of 500 or more and 5000 or less, a phenolic antioxidant (B-1), and an amine antioxidant (B-2). ) And an alkaline earth metal detergent (C), and the alkaline earth metal detergent (C) content in terms of alkaline earth metal atoms is lubricating oil. It is 1700 mass ppm or more and 2700 mass ppm or less on the basis of the total amount of the composition, and the kinematic viscosity at 100 ° C. is 4.0 mm ² / s or more and 6.0 mm ² / s or less.

  In the lubricating oil composition of one embodiment of the present invention, the total content of the base oil, the olefin oligomer (A), the antioxidant (B), and the alkaline earth metal detergent (C) is the lubricating oil composition Is preferably 70% by mass or more, more preferably 75% by mass or more, still more preferably 80% by mass or more, still more preferably 85% by mass or more, and still more preferably 90% by mass or more. Moreover, it is 100 mass% or less normally, Preferably it is 99.9 mass% or less, More preferably, it is 99 mass% or less.

Hereinafter, each component mix | blended with the lubricating oil composition of this embodiment is demonstrated.
<Olefin oligomer (A)>
The lubricating oil composition of the present embodiment contains an olefin oligomer (A), and the olefin oligomer (A) needs to have a mass average molecular weight of 500 or more and 5000 or less.
The olefin oligomer (A) has fluidity in a high-temperature part of an apparatus, for example, a transmission, and has an effect of washing away generated sludge. When the molecular weight of the olefin oligomer (A) is less than 500, it evaporates in a high temperature region and does not provide a sufficient cleaning effect. When the molecular weight of the olefin oligomer (A) exceeds 5,000, the fluidity in the high temperature region is not maintained, and the effect of washing off the sludge cannot be sufficiently exhibited.
The mass average molecular weight of the olefin oligomer (A) is preferably 600 or more and 4500 or less, more preferably 700 or more and 4000 or less, and still more preferably 800 or more and 3000 or less.

The olefin oligomer (A) is not particularly limited as long as it has a polyolefin skeleton and a molecular weight of 500 or more and 5000 or less. The olefin oligomer (A) preferably has a structural unit derived from an unsaturated hydrocarbon monomer having 2 to 5 carbon atoms, such as a propylene oligomer, an isobutylene oligomer, a polybutene, a polyisobutylene, an octene oligomer, a decene oligomer, and ethylene. -Olefin oligomers, such as a propylene oligomer, can be mentioned. Of these, polybutene-1 is preferably used.
An olefin oligomer (A) may be used individually by 1 type, and may use 2 or more types together.

The olefin oligomer (A) may be blended within a range in which the kinematic viscosity at 100 ° C. of the lubricating oil composition of the present embodiment is 4.0 mm ² / s or more and 6.0 mm ² / s or less. Specifically, the content of the olefin oligomer (A) having a mass average molecular weight of 500 or more and 5000 or less in the lubricating oil composition of the present embodiment is preferably 0.8% by mass based on the total amount of the lubricating oil composition. It is 4.5 mass% or less, More preferably, it is 1 mass% or more and 4 mass% or less, More preferably, it is 1.2 mass% or more and 2.5 mass% or less.

<Antioxidant (B)>
The lubricating oil composition of this embodiment contains an antioxidant (B), and the antioxidant (B) includes a phenol-based antioxidant (B-1), an amine-based antioxidant (B-2), and including. In this embodiment, it is necessary to use a phenolic antioxidant (B-1) and an amine antioxidant (B-2) in combination as the antioxidant (B), and only one of them is used. However, sufficient antioxidant performance cannot be obtained.

The phenolic antioxidant (B-1) is not particularly limited as long as it is a compound having a phenol structure and having an effect of suppressing oxidation of the lubricating oil composition.
Examples of the phenolic antioxidant (B-1) include 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, and 2,4,6. -Tri-tert-butylphenol, 2,6-di-tert-butyl-4-hydroxymethylphenol, 2,6-di-tert-butylphenol, 2,4-dimethyl-6-tert-butylphenol, 2,6-di -Tert-butyl-4- (N, N'-dimethylaminomethyl) phenol, 2,6-di-tert-amyl-4-methylphenol, 2,6-di-tert-amyl-p-cresol, 4, 4'-methylenebis (2,6-di-tert-butylphenol), 4,4'-bis (2,6-di-tert-butylphenol), 4,4'-bis (2 -Methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 4,4 ' -Butylidenebis (3-methyl-6-tert-butylphenol), 4,4'-isopropylidenebis (2,6-di-tert-butylphenol), 2,2'-methylenebis (4-methyl-6-nonylphenol), 2,2′-isobutylidenebis (4,6-dimethylphenol), 2,2′-methylenebis (4-methyl-6-cyclohexylphenol), 2,4-dimethyl-6-tert-butylphenol, 4,4 '-Thiobis (2-methyl-6-tert-butylphenol), 4,4'-thiobis (3-methyl-6-tert) Butylphenol), 2,2′-thiobis (4-methyl-6-tert-butylphenol), bis (3-methyl-4-hydroxy-5-tert-butylbenzyl) sulfide, bis (3,5-di-tert- Butyl-4-hydroxybenzyl) sulfide, 2,2′-thio-diethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], tridecyl-3- (3,5-di -Tert-butyl-4-hydroxyphenyl) propionate, pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octyl-3- (3,5-di-tert- Butyl-4-hydroxyphenyl) propionate, octadecyl-3- (3,5-di-tert) -Butyl-4-hydroxyphenyl) propionate, octyl-3- (3-methyl-5-tert-butyl-4-hydroxyphenyl) propionate, and the like.
In addition, in this embodiment, a phenolic antioxidant (B-1) may be used individually by 1 type, and may use 2 or more types together.

（式中、Ａｒ¹及びＡｒ²はそれぞれ独立に、フェニル基、アルキル基で置換されたフェニル基、アラルキル基で置換されたフェニル基、ナフチル基、及びアルキル基で置換されたナフチル基から選択される炭素数６〜２４のアリール基を示す）The amine-based antioxidant (B-2) that can be used in the present embodiment is not particularly limited. For example, the compound represented by the following general formula (B-2-1) is mentioned.

Wherein Ar ¹ and Ar ² are each independently selected from a phenyl group, a phenyl group substituted with an alkyl group, a phenyl group substituted with an aralkyl group, a naphthyl group, and a naphthyl group substituted with an alkyl group. An aryl group having 6 to 24 carbon atoms)

  More specifically, the amine-based antioxidant (B-2) includes phenyl-α-naphthylamines represented by the following general formula (B-2-2) and the general formula (B-2-3). It is preferable to be selected from diphenylamines represented by:

（式中、Ｒ¹は、水素原子、又は炭素数１〜１８のアルキル基を示す）

(Wherein R ¹ represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms)

（式中、Ｒ²及びＲ³は、それぞれ独立に水素原子、炭素数１〜１８のアルキル基、又は炭素数７〜１８のアラルキル基を示す）。

(In the formula, R ² and R ³ each independently represent a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, or an aralkyl group having 7 to 18 carbon atoms).

Specific examples of the amine antioxidant (B-2) include monoalkyl diphenylamines such as monooctyl diphenylamine and monononyl diphenylamine; 4,4′-dibutyldiphenylamine, 4,4′-dipentyldiphenylamine, 4, Dialkyldiphenylamines such as 4′-dihexyldiphenylamine, 4,4′-diheptyldiphenylamine, 4,4′-dioctyldiphenylamine, 4,4′-dinonyldiphenylamine; tetrabutyldiphenylamine, tetrahexyldiphenylamine, tetraoctyldiphenylamine, tetra Polyalkyldiphenylamines such as nonyldiphenylamine, α-naphthylamine, naphthylamines such as phenyl-α-naphthylamine, butylphenyl-α-naphthylamine, Alkyl-substituted phenyl-α-naphthylamines such as tilphenyl-α-naphthylamine, hexylphenyl-α-naphthylamine, heptylphenyl-α-naphthylamine, octylphenyl-α-naphthylamine, nonylphenyl-α-naphthylamine; diphenylamine, monobutylphenylmonooctyl Examples include phenylamine, Npt-octylphenyl-1-naphthylamine, 4,4′-bis (α, α-dimethylbenzyl) diphenylamine, and the like.
In addition, in this embodiment, an amine antioxidant (B-2) may be used individually by 1 type, and may use 2 or more types together.

Specific examples of the phenolic antioxidant (B-1) and the amine antioxidant (B-2) used in combination as the antioxidant (B) include pentaerythritol tetrakis [3- (3,5-di- tert-butyl-4-hydroxyphenyl) propionate] or octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate (B-1) and monobutylphenyl monooctylphenylamine Or any combination with (B-2) which is Npt-octylphenyl-1-naphthylamine.
In the present embodiment, the content of the antioxidant (B) including the phenolic antioxidant (B-1) and the amine antioxidant (B-2) is based on the total amount of the lubricating oil composition. Preferably they are 0.5 mass% or more and 3.0 mass% or less, More preferably, they are 0.5 mass% or more and 2.0 mass% or less, More preferably, they are 1 mass% or more and 2 mass% or less. Here, content of antioxidant (B) shows the total amount of a phenolic antioxidant (B-1) and an amine antioxidant (B-2).
When the content of the antioxidant (B) is 0.5% by mass or more, the antioxidant effect is sufficiently exhibited. From the viewpoint of the antioxidant effect, 3.0 mass% is sufficient as the upper limit of the content of the antioxidant (B).
Further, the mass ratio [(B-2) / (B-1)] of the phenolic antioxidant (B-1) to the amine antioxidant (B-2) is not particularly limited, but 1/3 It is preferably about 3/1, and more preferably about 1/2 to 2/1.
Furthermore, in this embodiment, the total content of the phenolic antioxidant (B-1) and the amine antioxidant (B-2) in the antioxidant (B) is the total amount of the antioxidant (B). Preferably, it is 60% by mass or more and 100% by mass or less, more preferably 70% by mass or more and 100% by mass or less, still more preferably 80% by mass or more and 100% by mass or less, and still more preferably 90% by mass or more and 100% by mass or less. Still more preferably, it is 99 mass% or more and 100 mass% or less.

As described above, in this embodiment, it is essential to use the phenolic antioxidant (B-1) and the amine antioxidant (B-2) in combination as the antioxidant (B). It does not exclude including other antioxidants as long as the effects of the embodiments are not impaired. Examples of other antioxidants include molybdenum amine complex antioxidants.
As the molybdenum amine complex-based antioxidant, a hexavalent molybdenum compound, specifically, a product obtained by reacting molybdenum trioxide and / or molybdic acid with an amine compound, for example, as described in JP-A No. 2003-252887 A compound obtained by the production method can be used.

<Alkaline earth metal detergent (C)>
The lubricating oil composition of the present embodiment contains an alkaline earth metal detergent (C), and the content of the alkaline earth metal detergent (C) in terms of alkaline earth metal atoms is the lubricating oil composition. It needs to be 1700 mass ppm or more and 2700 mass ppm or less on the basis of the total amount of things.
The alkaline earth metal detergent (C) has a cleaning effect of suppressing the generation of sludge and dispersing the generated sludge by the acid neutralization action of the deteriorated component generated in the oil.
When the content of the alkaline earth metal detergent (C) in terms of the alkaline earth metal atom in terms of the total amount of the lubricating oil composition is less than 1700 mass ppm, the neutralizing action described above is sufficiently exhibited. Inferior in oxidation stability and heat resistance. If the content of alkaline earth metal detergent (C) in terms of alkaline earth metal atoms exceeds 2700 ppm by mass, the amount of metal in the composition will increase and become the core of sludge formation, resulting in poor heat resistance. It becomes. The content of the alkaline earth metal detergent (C) in terms of alkaline earth metal atoms, based on the total amount of the lubricating oil composition, is preferably 1800 ppm to 2600 ppm, more preferably 1900 ppm. It is 2500 mass ppm or less, More preferably, it is 2000 mass ppm or more and 2500 mass ppm or less.

As the alkaline earth metal detergent (C), at least one selected from the group consisting of an alkaline earth metal sulfonate, an alkaline earth metal phenate, and an alkaline earth metal salicylate described in detail below is used. It may be a mixture of two or more. Among these, alkaline earth metal sulfonates are preferable in terms of heat resistance.
Alkaline earth metal sulfonates include alkaline earth metal salts of alkyl aromatic sulfonic acids obtained by sulfonated alkyl aromatic compounds having a molecular weight of 300 to 1,500, preferably 400 to 700, particularly magnesium salts and / or Or a calcium salt etc. can be mentioned. Among them, it is preferable to use a calcium salt. Alkaline earth metal phenates include alkylphenols, alkylphenol sulfides, alkaline earth metal salts of Mannich reactants of alkylphenols, particularly magnesium salts and / or calcium salts, among which calcium salts are particularly preferred. Examples of the alkaline earth metal salicylates include alkaline earth metal salts of alkyl salicylic acid, particularly magnesium salts and / or calcium salts, among which calcium salts are preferred.
The number of carbon atoms of the alkyl group constituting the alkaline earth metal detergent (C) is preferably 4-30, more preferably 6-18, and the alkyl group may be linear or branched. The alkyl group may be a primary alkyl group, a secondary alkyl group, or a tertiary alkyl group.
The alkaline earth metal sulfonate, alkaline earth metal phenate, and alkaline earth metal salicylate may be neutral, basic, or overbased. Examples of the neutral alkaline earth metal salt include, for example, the above-mentioned alkyl aromatic sulfonic acid, alkylphenol, alkylphenol sulfide, Mannich reaction product of alkylphenol, alkyl salicylic acid and the like, and an alkaline earth metal oxide of magnesium and / or calcium. A neutral alkaline earth metal sulfonate obtained by reacting with an alkaline earth metal base such as sodium hydroxide or hydroxide, or once replacing the alkaline earth metal salt such as sodium salt or potassium salt with an alkaline earth metal salt, Mention may be made of neutral alkaline earth metal phenates and neutral alkaline earth metal salicylates. Examples of the basic alkaline earth metal salt include, for example, the above neutral alkaline earth metal sulfonate, neutral alkaline earth metal phenate and neutral alkaline earth metal salicylate, excess alkaline earth metal salt and alkaline earth metal base. And basic alkaline earth metal sulfonates, basic alkaline earth metal phenates and basic alkaline earth metal salicylates obtained by heating in the presence of water. As the overbased alkaline earth metal salt, for example, the above-mentioned neutral alkaline earth metal sulfonate, neutral alkaline earth metal phenate and neutral alkaline earth metal salicylate in the presence of carbon dioxide gas are mixed with alkaline earth metal carbonate. Mention may be made of overbased alkaline earth metal sulfonates, overbased alkaline earth metal phenates and overbased alkaline earth metal salicylates obtained by reacting salts or borates. The alkaline earth metal detergent (C) is usually commercially available in a state diluted with a light lubricating base oil or the like, and is available, but generally the metal content is 1.0. It is preferable to use -20% by mass, preferably 2.0-16% by mass.

There is no restriction | limiting in particular in the metal ratio of the alkaline-earth metal type cleaning agent (C) of this embodiment, Usually, 20 or less things can be used 1 type or in mixture of 2 or more types. The metal ratio is preferably 3 or less, more preferably 1.5 or less, and particularly preferably 1.2 or less, because it is excellent in oxidation stability, base number maintenance, and heat resistance at high temperatures.
The metal ratio here is represented by the valence of the metal element in the metal-based detergent × metal element content (mol%) / soap group content (mol%), and the metal elements include calcium, magnesium, and the like. The soap group means a sulfonic acid group, a phenol group, a salicylic acid group, or the like.

  The alkaline earth metal detergent (C) may be neutral, basic or overbased as described above, for example, usually 10 mgKOH / g or more and 500 mgKOH / g or less, preferably 15 mgKOH / g or more and 450 mgKOH / g. The alkaline earth metal detergent (C) which has the following base numbers can be mentioned, and it can use together 1 type, or 2 or more types. In the present embodiment, those having basicity or overbasing are more preferable, and preferably have a base number of 150 mgKOH / g or more and 450 mgKOH / g or less. By having a base number of 150 mgKOH / g or more and 450 mgKOH / g or less, it exhibits excellent oxidation stability and excellent heat resistance. In addition, the base number of alkaline earth metal detergent (C) as used in this specification shows what was measured by JISK 2501: 2003: perchloric acid method. The base number of the alkaline earth metal detergent (C) is more preferably from 200 mgKOH / g to 450 mgKOH / g, still more preferably from 250 mgKOH / g to 400 mgKOH / g.

  Examples of the alkaline earth metal atom contained in the alkaline earth metal detergent (C) include one or more selected from beryllium atom, magnesium atom, calcium atom, strontium atom, and barium atom. From the viewpoint of improving high-temperature heat resistance, calcium, magnesium, or barium is preferable, calcium or magnesium is more preferable, and calcium is more preferable. Calcium sulfonate can be suitably used as the alkaline earth metal detergent (C).

<Polymer (D) having a mass average molecular weight exceeding 5000>
The lubricating oil composition in the present embodiment may contain a polymer (D) having a mass average molecular weight of more than 5000. However, when it contains this polymer (D), it is preferable that content of a polymer (D) is less than 50 mass parts with respect to 100 mass parts of olefin oligomers (A). If the ratio with respect to 100 mass parts of olefin oligomer (A) is the said range, the heat resistance in the high temperature part of a transmission can be maintained, for example. Moreover, if the quantity of a polymer (D) is the said range, the viscosity fall in the actual vehicle running etc. resulting from the shearing of a high molecular compound etc. can be reduced as much as possible. The content of the polymer (D) is more preferably less than 30 parts by mass and even more preferably less than 20 parts by mass with respect to 100 parts by mass of the olefin oligomer (A). The weight average molecular weight of the polymer (D) is preferably 120,000 or less, more preferably 50,000 or less, and further preferably 40,000 or less.
A polymer (D) is not specifically limited, The polymethacrylate etc. which are generally used as a pour point depressant can be mentioned. Even if it does not contain a viscosity index improver, the lubricating oil composition of this embodiment can maintain a stable oil film strength even at high temperatures, and therefore does not need to contain a viscosity index improver. Moreover, also when it contains the polymer (D) classified into a viscosity index improver, the outstanding shear stability is implement | achieved by making it in the range of the said mass ratio.

<Zinc dithiophosphate (E)>
The lubricating oil composition in the present embodiment may contain zinc dithiophosphate (E). As zinc dithiophosphate (E), what is shown with the following general formula (E-1) is used.

（式中、Ｒ⁴〜Ｒ⁷は、それぞれ独立に、炭素数１〜２４の直鎖状、分岐状又は環状のアルキル基、及び炭素数１〜２４の直鎖状、分岐状又は環状のアルケニル基から選ばれる基を示す）

(In the formula, R ^{4 to} R ⁷ are each independently a linear, branched or cyclic alkyl group having 1 to 24 carbon atoms, and a linear, branched or cyclic alkenyl group having 1 to 24 carbon atoms. A group selected from a group)

In General Formula (E-1), R ^{4 to} R ⁷ are each independently a linear, branched, or cyclic alkyl group having 1 to 24 carbon atoms, or a linear or branched group having 1 to 24 carbon atoms. And cyclic alkenyl groups may be different or the same, but the same are preferable from the viewpoint of ease of production.
R ⁴ to R ⁷ is preferably a straight-chain, also R ⁴ to R ⁷ is preferably an alkyl group.

Examples of the alkyl group in R ^{4 to} R ⁷ include 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, Examples include tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, heicosyl group, docosyl group, tricosyl group, and tetracosyl group, which are linear, branched, or cyclic. May be. As alkenyl groups, vinyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl Group, heptadecenyl group, octadecenyl group, nonadecenyl group, icocenyl group, henicocenyl group, dococenyl group, tricocenyl group, tetracocenyl group, these may be any of linear, branched or cyclic, double The position of the bond is also arbitrary.

  When the lubricating oil composition of the present embodiment contains zinc dithiophosphate (E), the content is usually 0.05% by mass or more and 5% by mass or less, preferably 0.1% based on the total amount of the composition. The content is from 3% by mass to 3% by mass, and more preferably from 1% by mass to 2.5% by mass. If the content of zinc dithiophosphate (E) is within the above range, for example, when used as MTF (manual transmission fluid), the coefficient of friction (μ) can be improved at the time of shifting, and the shift feeling is improved. be able to.

<Base oil>
The base oil used in the present embodiment may be either mineral oil or synthetic oil, or a mixed oil of mineral oil and synthetic oil.
As the mineral oil, for example, atmospheric residual oil obtained by atmospheric distillation of crude oil such as paraffinic crude oil, mixed crude oil, naphthenic crude oil; distillate oil obtained by vacuum distillation of these atmospheric residual oils; Examples include refined oils and waxes obtained by subjecting the distillate to one or more purification treatments such as solvent deburring, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, and hydrogenation reforming.

In the present embodiment, from the viewpoint of suppressing sludge generation, mineral oil classified into Group 2 or 3 in the base oil category of API (American Petroleum Institute) is preferable. In order to improve the oxidation stability, those classified into Group 3 are more preferable. In addition, the base oil classified into Group 2 has a saturation content of 90% or more, a sulfur content of 0.03% or less, and a viscosity index of 80 to less than 120. Base oils classified as Group 3 have a saturation content of 90% or more, a sulfur content of 0.03% or less, and a viscosity index of 120 or more.
The sulfur content is a value measured according to JIS K2541-6: 2013, and the saturated content is a value measured according to ASTM D 2007. Furthermore, the viscosity index is a value measured in accordance with JISK 2283: 2000.

  Synthetic oils include polyol esters, dibasic acid esters (for example, ditridecyl glutarate), tribasic acid esters (for example, 2-ethylhexyl trimellitic acid), phosphoric acid esters, and the like; polyphenyl ethers, etc. Examples include various ethers; polyalkylene glycols; alkyl benzenes; alkyl naphthalenes; synthetic oils obtained by isomerizing waxes (GTL (Gas-To-Liquids) waxes) produced by the Fischer-Tropsch method and the like.

In this embodiment, these base oils may be used independently and may be used in combination of 2 or more type. The kinematic viscosity at 100 ° C. of the base oil used in the present embodiment is preferably 2.0 mm ² / s to 30 mm ² / s, more preferably 2.5 mm ² / s to 25 mm ² / s, and further preferably 3 .0mm is less than or equal to ² / s more than 20mm ² / s.

The viscosity index of the base oil used in the present embodiment is preferably 80 or higher, more preferably 90 or higher, from the viewpoint of suppressing the change in viscosity due to temperature change and improving the fuel efficiency. Preferably it is 120 or more.
In addition, when using the mixed oil which combined 2 or more types of base oil, it is preferable that the kinematic viscosity and viscosity index of the said mixed oil are the said range.

  In the present embodiment, the content of the base oil is preferably 75% by mass or more, more preferably 80% by mass or more, still more preferably 85% by mass or more, preferably based on the total amount of the composition. It is 97 mass% or less, More preferably, it is 95 mass% or less.

<Other additives>
The transmission lubricating oil composition of this embodiment may contain additives such as friction modifiers, dispersants, and antifoaming agents. However, the pour point depressant is classified as a polymer (D) having a mass average molecular weight exceeding 5000, and is not included in other additives.
The blending amount of the additive is preferably 10% by mass or less, more preferably 7.5% by mass or less, and still more preferably 5.0% by mass or less, based on the total amount of the composition.

<Physical properties of lubricating oil composition>
The kinematic viscosity at 100 ° C. of the lubricating oil composition of the present embodiment is 4.0 mm ² / s to 6.0 mm ² / s. When the kinematic viscosity at 100 ° C. is less than 4.0 mm ² / s, the oil film strength is lowered, leading to seizure resistance, wear resistance, fatigue resistance, and the like. When the kinematic viscosity at 100 ° C. exceeds 6.0 mm ² / s, the stirring resistance increases, which is not preferable in terms of fuel saving.
The kinematic viscosity at 100 ° C. of the lubricating oil composition of the present embodiment is more preferably 4.5 mm ² / s to 5.8 mm ² / s, and even more preferably 4.6 mm ² / s to 5.5 mm ^2. / S or less.

<Application, lubrication method, transmission>
The lubricating oil composition of this embodiment can be suitably used for transmission oil applications.
The lubricating oil composition of the present embodiment has a low viscosity, suppresses a decrease in viscosity during actual vehicle travel, and is excellent in heat resistance and oxidation stability. Therefore, in a transmission that has been reduced in size and weight, for example, adhesion of sludge in a synchromesh mechanism is suppressed, and a good shift feeling can be obtained. Also, the synchronizer ring operation can be kept good. Therefore, this embodiment can also provide a lubricating method and a using method using the above-described lubricating oil composition.
The present embodiment can also provide a transmission filled with the above-described lubricating oil composition.

<Method for producing lubricating oil composition>
The lubricating oil composition of this embodiment comprises a base oil, an olefin oligomer (A) having a mass average molecular weight of 500 or more and 5000 or less, a phenolic antioxidant (B-1) and an amine antioxidant (B-2). And an antioxidant (B) containing alkaline earth metal and a alkaline earth metal detergent (C), respectively, wherein the alkaline earth metal detergent (C) is lubricated. It can manufacture by mix | blending so that content in conversion of an alkaline-earth metal atom may be 1700 mass ppm or more and 2700 mass ppm or less on the basis of the whole quantity of an oil composition.

  Next, the present embodiment will be described more specifically by way of examples. However, the present embodiment is not limited to these examples.

<Each measurement method>
(1) Mass average molecular weight (Mw)
It was measured by standard polystyrene conversion by GPC (gel permeation chromatography) method. Specifically, the measurement was performed under the following apparatus and conditions.
-GPC equipment: Waters 1515 Isocratic HPLC Pump + Waters 2414 Refractive Index Detector (all manufactured by Waters)
-Column: Two "TSKgel SuperMultipore HZ-M" (manufactured by Tosoh Corporation) connected.-Column temperature: 40 ° C
-Eluent: Tetrahydrofuran-Flow rate: 0.35 mL / min
-Detector: Refractive index detector (2) Kinematic viscosity Kinematic viscosity at each temperature was measured according to JIS K2283: 2000.
(3) Content of calcium atom, content of nitrogen atom, content of phosphorus atom and content of sulfur atom in lubricating oil composition The content of each component was measured by the following method.
(3-1) Content of calcium atom (Ca) and content of phosphorus atom (P) It measured based on JPI-5S-38-92.
(3-2) Content of nitrogen atom (N) Measured according to JIS K2609: 1998.
(3-3) Content of Sulfur Atom (S) Measured according to JIS K2541-6: 2013.

<Evaluation method>
(I) Panel coking test
In accordance with Federal test method 791B / 3462, the panel temperature was 300 ° C. and the oil temperature was 100 ° C., and the test was conducted for 3 hours with a cycle of a splash time of 15 seconds and a stop time of 45 seconds. After completion of the test, the weight (mg) of the caulk adhered to the panel was measured.
(II) Oxidation stability In the ISOT test (165.5 ° C.) based on JIS K2514-1: 2013, a test piece (lubricating oil composition) is put into a test piece (lubricating oil composition) with a piece of copper and an iron piece, and the test oil is forcibly degraded. The base number (perchloric acid method) after 96 hours was measured. The higher the base value after the test, the higher the base number retention and the longer drain oil that can be used for a longer period. Moreover, the n-pentane insoluble matter (Method A) was measured after the ISOT test.
(III) Shear stability Based on JIS K2283: 2000, the kinematic viscosity of 100 degreeC before a test and after a shear test was measured, and shear stability was computed by the following formula. Further, the shear test was performed based on the ultrasonic wave A method (JPI-5S-29-06) under measurement conditions of ultrasonic irradiation time of 60 minutes, room temperature, and oil amount of 30 cc. The output voltage of the ultrasonic wave in the shear stability test was an output voltage at which the rate of decrease in kinematic viscosity at 100 ° C. was 25% after 30 cc of standard oil was irradiated with ultrasonic waves for 10 minutes.
Shear stability (%) = {([Kinematic viscosity before test] − [Kinematic viscosity after test]) / [Kinematic viscosity before test]} × 100

Examples 1-6 and Comparative Examples 1-7
Lubricating oil compositions were prepared by blending the components shown in Tables 1 and 2. For the lubricating oil compositions prepared in each Example and Comparative Example, the acid values before various tests, 40 ° C. kinematic viscosity, 100 ° C. kinematic viscosity, calcium, nitrogen, phosphorus and sulfur amounts were measured, and the above ( The tests shown in I) to (III) were performed. These results are also shown in the table.

Each compounding material of the said Example and a comparative example is as follows.
<Combination material>
(1) Mineral oil classified into Group III of the base oil / API base oil category (kinematic viscosity at 40 ° C .: 18.9 mm ² / s, kinematic viscosity at 100 ° C .: 4.2 mm ² / s, viscosity index: 128)
(2) Olefin oligomer component (A)
Oligomer 1: Polybutene-1 having a weight average molecular weight (Mw) of 940
Oligomer 2: Polybutene-1 having a weight average molecular weight (Mw) of 2300
Olefin oligomer / oligomer 3 other than the component (A): Decene oligomer / oligomer 4 having a mass average molecular weight (Mw) of 10,000: Ethylene-propylene oligomer having a mass average molecular weight (Mw) of 12000: Mass average molecular weight (Mw) 17000 ethylene-propylene (3) antioxidant (B)
Phenolic antioxidant (B-1)
Antioxidant (B-1-A): Octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate Antioxidant (B-1-B): Pentaerythritol tetrakis [3 -(3,5-di-tert-butyl-4-hydroxyphenyl) propionate]
Amine-based antioxidant (B-2)
-Antioxidant (B-2-C): Monobutylphenyl monooctylphenylamine-Acid value inhibitor (B-2-D): Npt-octylphenyl-1-naphthylamine (4) Alkaline earth Metal detergent (C)
・ Overbased calcium sulfonate (base number: 400 mgKOH / g, JISK 2501: 2003: measured by perchloric acid method)
(5) Zinc dithiophosphate (E)
・ Zinc dihexyl dithiophosphate (n-hexyl group)
(6) Other additives: Sulfur-based extreme pressure agent, dispersant, ashless friction modifier and antifoaming agent

From Table 1, it can be seen that the lubricating oil compositions of Examples 1 to 6 have a low 100 ° C. kinematic viscosity and are excellent in heat resistance and oxidation stability. In addition, since a polymer with a high molecular weight such as a viscosity index improver that causes a decrease in viscosity due to shear is not required, the viscosity decrease rate is low even after the shear test, and the viscosity decrease during actual vehicle running is sufficiently suppressed. You can see that
On the other hand, Table 2 shows the following. From Comparative Example 1, it can be seen that if the content of the component (C) in terms of calcium atom in terms of the total amount of the lubricating oil composition is less than this embodiment, the oxidation stability is poor. As in Comparative Example 2, if the content of the component (C) in terms of calcium atom on the basis of the total amount of the lubricating oil composition is too high, the amount of sludge increases and the heat resistance is poor. It turns out that it is inferior to heat resistance when the thing of the mass mean molecular weight outside this application range is used as an olefin oligomer like Comparative Examples 3-5. In particular, Comparative Example 5 is inferior in shear stability because the oligomer used has a mass average molecular weight of 17,000. From Comparative Examples 6 and 7, it can be seen that when the phenolic antioxidant and the amine antioxidant are not used together as the antioxidant (B), the heat resistance is also poor.

  According to the present invention, there is provided a lubricating oil composition that achieves low viscosity, suppresses a decrease in viscosity during actual vehicle travel, and achieves improvement in heat resistance and oxidation stability accompanying reduction in size and weight of the apparatus. be able to.

Claims (14)

Along with the base oil
Olefin oligomer (A) having a mass average molecular weight of 500 or more and 5000 or less,
Antioxidant (B) containing phenolic antioxidant (B-1) and amine antioxidant (B-2), and alkaline earth metal detergent (C)
Including
The content of the alkaline earth metal detergent (C) in terms of alkaline earth metal atoms is 1700 mass ppm or more and 2700 mass ppm or less based on the total amount of the lubricating oil composition,
A lubricating oil composition having a kinematic viscosity at 100 ° C. of 4.0 mm ² / s or more and 6.0 mm ² / s or less.   The lubricating oil composition according to claim 1, wherein the content of the olefin oligomer (A) is 0.8% by mass or more and 4.5% by mass or less based on the total amount of the lubricating oil composition.   The lubricating oil composition according to claim 1 or 2, wherein the olefin oligomer (A) contains a structural unit derived from an unsaturated hydrocarbon monomer having 2 to 5 carbon atoms.   The lubricating oil composition according to any one of claims 1 to 3, wherein the olefin oligomer (A) is polybutene.   The lubricating oil composition according to any one of claims 1 to 4, wherein the alkaline earth metal detergent (C) is an alkaline earth metal salt having a base number of 150 mgKOH / g or more and 450 mgKOH / g or less. .   The alkaline earth metal detergent (C) is at least one selected from the group consisting of alkaline earth metal sulfonates, alkaline earth metal phenates, and alkaline earth metal salicylates. The lubricating oil composition according to claim 1.   The lubricating oil composition according to any one of claims 1 to 6, wherein the alkaline earth metal atom of the alkaline earth metal detergent (C) is a calcium atom or a magnesium atom.   Lubricating oil as described in any one of Claims 1-7 whose content of antioxidant (B) is 0.5 to 3.0 mass% on the basis of the total amount of the lubricating oil composition. Composition.   Furthermore, the lubricating oil composition as described in any one of Claims 1-8 containing zinc dithiophosphate (E).   A lubricating oil composition, wherein the lubricating oil composition according to any one of claims 1 to 9 is for a transmission.   A transmission filled with the lubricating oil composition according to claim 1.   The lubricating method using the lubricating oil composition as described in any one of Claims 1-9.   The usage method for the transmission of the lubricating oil composition as described in any one of Claims 1-9.   An antioxidant (B) containing an olefin oligomer (A) having a mass average molecular weight of 500 or more and 5000 or less, a phenolic antioxidant (B-1) and an amine antioxidant (B-2) in the base oil, And an alkaline earth metal detergent (C), respectively, wherein the alkaline earth metal detergent (C) is alkaline earth based on the total amount of the lubricating oil composition. The manufacturing method of the lubricating oil composition mix | blended so that content in conversion of a similar metal atom may be 1700 mass ppm or more and 2700 mass ppm or less.