JP2021188031A - Lubricant base oil for power transmission - Google Patents

Abstract

To provide a lubricant base oil for power transmission that has a high traction coefficient and a high flash point, and excellent low-temperature fluidity.SOLUTION: Specifically for example, ester compounds such as 3,5,5-trimethyl-1-hexanoic acid 2-(1,3,3-trimethyl butyl)-5,7,7-trimethyl-1-octyl, and 2-(1,3,3-trimethyl butyl)-5,7,7-trimethyl-1-octanoic acid 3,5,5-trimethyl 1-hexyl, are used as a lubricant base oil for power transmission.SELECTED DRAWING: None

Description

The present invention relates to a lubricating oil base oil for power transmission. Specifically, the present invention relates to a lubricating oil base oil for a traction drive.

In recent years, the socialization of digital information has progressed, and the accuracy required for printing machines and copiers has increased. In particular, in the motor section where high-precision paper feed is required, high rotation accuracy, low vibration, and low noise are required. When the gear system is adopted as the power transmission means of these rotating parts, vibration and noise are large, so that a traction drive with few of them is often used.

In addition, industrial robots are becoming more widespread, and traction drives are also used in joints where precise movements are required. In addition, traction drives are being put to practical use in fields such as continuously variable transmissions for industrial equipment, aircraft generators, and helicopter rotor rotation speed control. In order to increase the amount of power transmission, studies have been made on increasing the size of the traction drive, but the amount of heat generated tends to increase as the contact area increases.

The lubricating oil base oil for power transmission is preferably one having a high traction coefficient in order to enhance the power transmission ability, and an alicyclic hydrocarbon compound or the like has been proposed. For example, dicyclohexyl compounds typified by 2-methyl-2,4-dicyclohexylpentane, dimerized norbornanes and the like can be mentioned (Patent Documents 1 and 2).

However, alicyclic hydrocarbon compounds typified by 2-methyl-2,4-dicyclohexylpentane tend to have a low flash point of 200 ° C or lower, and heat resistance and safety for which large traction drives and the like are adopted. Was not always sufficient in areas where is important.

Further, an ester compound has been proposed as a lubricating oil base oil for power transmission having a high flash point. For example, an alicyclic diester compound typified by 1,2-cyclohexanedicarboxylic acid di (cyclohexylmethyl) and the like can be mentioned (Patent Document 3).

However, alicyclic diester compounds typified by 1,2-cyclohexanedicarboxylic acid di (cyclohexylmethyl) tend to have a high pour point of -20 ° C or higher, and are operable at low temperatures such as aircraft, helicopters, and automobiles. It was not always enough in the field where the importance was placed.

Japanese Unexamined Patent Publication No. 47-7664 Japanese Unexamined Patent Publication No. 3-95295 International publication number WO2018 / 008667

An object of the present invention is to provide a power transmission lubricating oil base oil (particularly, a traction drive lubricating oil base oil) having a high traction coefficient and ignition point and good low temperature fluidity.

The present inventors have found that a specific ester compound has a high traction coefficient and flash point, and has good low temperature fluidity. The present invention has been completed by further studying based on such findings.

That is, the present invention provides a lubricating oil base oil for power transmission (particularly, a lubricating oil base oil for traction drive) having the following items.

［式中、Ｒ^１は、炭素数４〜１２の分岐鎖状アルキル基（該分岐鎖状アルキル基は主鎖である直鎖状アルキル基とこれに結合した２個若しくは３個以上の炭素数１〜３のアルキル基（分枝）とからなる）を表し、Ｘは、下記の（ａ）又は（ｂ）

を表す。］
で表されるエステル化合物を含有する動力伝達用潤滑油基油。 [Item 1]
General formula (1)

[In the formula, R ¹ is a branched chain alkyl group having 4 to 12 carbon atoms (the branched chain alkyl group is a linear alkyl group which is a main chain and has two or three or more carbon atoms bonded thereto. Represents (consisting of 1 to 3 alkyl groups (branches)), where X is the following (a) or (b).

Represents. ]
Lubricating oil base oil for power transmission containing an ester compound represented by.

[Item 2]
The lubricating oil base oil for power transmission according to [Item 1], wherein ^{R 1 according} to the general formula (1) has 7 to 10 carbon atoms.

[Item 3]
The lubricating oil base oil for power transmission according to [Item 1] or [Item 2], wherein ^{R 1 according} to the general formula (1) has 8 carbon atoms.

[Item 4]
The lubricating oil base oil for power transmission according to any one of [Item 1] to [Item 3], wherein the ester compound is an ester compound represented by the following general formula (2) or general formula (3).

[Item 5]
Item 2. The power transmission item according to any one of [Item 1] to [Item 4], wherein the content of the ester compound represented by the general formula (1) is 70% by mass or more in the power transmission lubricating oil base oil. Lubricating oil base oil.

[Item 6]
Item 2. The power transmission item according to any one of [Item 1] to [Item 5], wherein the content of the ester compound represented by the general formula (1) is 90% by mass or more in the power transmission lubricating oil base oil. Lubricating oil base oil.

[Item 7]
The power transmission lubricating oil base oil according to any one of [Item 1] to [Item 6], wherein the power transmission lubricating oil base oil is a traction drive lubricating oil base oil.

[Item 8]
The power transmission lubricating oil containing the power transmission lubricating oil base oil according to any one of [Item 1] to [Item 7].

[Item 9]
A power transmission lubricating oil, which comprises the power transmission lubricating oil base oil and the antioxidant according to any one of [Item 1] to [Item 7].

[Item 10]
Item 9. The lubricating oil for power transmission according to [Item 9], wherein the antioxidant is a phenolic antioxidant and / or an amine-based antioxidant.

Since the specific ester compound of the present invention has high traction coefficient and ignition point and good low temperature fluidity, it is a lubricating oil base oil for power transmission (particularly, a lubricating oil for traction drive). It can be suitably used as a base oil).

［式中、Ｒ^１は、炭素数４〜１２の分岐鎖状アルキル基（該分岐鎖状アルキル基は主鎖である直鎖状アルキル基とこれに結合した２個若しくは３個以上の炭素数１〜３のアルキル基（分枝）とからなる）を表し、Ｘは、下記の（ａ）又は（ｂ）

を表す。］
で表される特定のエステル化合物を含有していることを特徴とする。 The lubricating oil base oil for power transmission of the present invention is of the general formula (1).

[In the formula, R ¹ is a branched chain alkyl group having 4 to 12 carbon atoms (the branched chain alkyl group is a linear alkyl group which is a main chain and has two or three or more carbon atoms bonded thereto. Represents (consisting of 1 to 3 alkyl groups (branches)), where X is the following (a) or (b).

Represents. ]
It is characterized by containing a specific ester compound represented by.

^{R 1} described in the general formula (1) is a branched alkyl group having 4 to 12 carbon atoms (the branched alkyl group is a linear alkyl group which is a main chain and two or three bonded to the linear alkyl group. It is composed of the above alkyl groups (branches) having 1 to 3 carbon atoms), and preferably a branched chain alkyl group having 7 to 10 carbon atoms.

Further, a branched chain alkyl group composed of a linear alkyl group which is a main chain and two or three or more methyl groups (branches) bonded thereto is preferable.

Specific examples of R ¹ include a 1,1-dimethylethyl group, a 1,1-dimethylpropyl group, a 1,2-dimethylpropyl group, a 2,2-dimethylpropyl group, and a 1,1,2-trimethylpropyl group. Group, 1,2,2-trimethylpropyl group, 1,1-dimethylbutyl group, 1,2-dimethylbutyl group, 1,3-dimethylbutyl group, 2,2-dimethylbutyl group, 2,3-dimethylbutyl Group, 3,3-dimethylbutyl group, 1,1,2-trimethylbutyl group, 1,1,3-trimethylbutyl group, 1,2,2-trimethylbutyl group, 2,2,3-trimethylbutyl group, 1,3,3-trimethylbutyl group, 2,3,3-trimethylbutyl group, 1,2,3-trimethylbutyl group, 1,1-dimethylpentyl group, 1,2-dimethylpentyl group, 1,3- Dimethylpentyl group, 1,4-dimethylpentyl group, 2,2-dimethylpentyl group, 2,3-dimethylpentyl group, 2,4-dimethylpentyl group, 3,3-dimethylpentyl group, 3,4-dimethylpentyl group Group, 4,4-dimethylpentyl group, 1,1,2-trimethylpentyl group, 1,1,3-trimethylpentyl group, 1,1,4-trimethylpentyl group, 1,2,2-trimethylpentyl group, 2,2,3-trimethylpentyl group, 2,2,4-trimethylpentyl group, 1,3,3-trimethylpentyl group, 2,3,3-trimethylpentyl group, 3,3,4-trimethylpentyl group, 1,4,4-trimethylpentyl group, 2,4,4-trimethylpentyl group, 3,4,4-trimethylpentyl group, 1,2,3-trimethylpentyl group, 1,2,4-trimethylpentyl group, 1,3,4-trimethylpentyl group, 2,3,4-trimethylpentyl group, 1,1-dimethylhexyl group, 1,2-dimethylhexyl group, 1,3-dimethylhexyl group, 1,4-dimethylhexyl Group, 1,5-dimethylhexyl group, 2,2-dimethylhexyl group, 2,3-dimethylhexyl group, 2,4-dimethylhexyl group, 2,5-dimethylhexyl group, 3,3-dimethylhexyl group, 3,4-dimethylhexyl group, 3,5-dimethylhexyl group, 4,4-dimethylhexyl group, 4,5-dimethylhexyl group, 5,5-dimethylhexyl group, 1,1,2-trimethylhexyl group, 1,1,3-trimethylhexyl group, 1,1,4-trimethylhexyl group, 1,1,5-trimethylhexyl group, 1,2,2-trimethylhexyl group, 2,2,3-trimethylhexyl group, 2,2,4-trimethylhexyl group, 2,2,5-trimethylhexyl group, 1,3,3-trimethylhexyl group, 2,3,3-trimethylhexyl group, 3,3,4-trimethylhexyl group, 3,3,5-trimethylhexyl group, 1,4,4-trimethylhexyl group, 2,4,4-trimethylhexyl group, 3,4,4-trimethylhexyl group, 4,4,5-trimethylhexyl group, 1,5,5-trimethylhexyl group, 2,5,5-trimethylhexyl group, 3,5,5-trimethylhexyl group, 4,5,5-trimethylhexyl group, 1,2,3-trimethylhexyl group, 1,2,4-trimethylhexyl group, 1,2,5-trimethylhexyl group, 1,3,4-trimethylhexyl group, 1,3,5-trimethylhexyl group, 1,4,5-trimethylhexyl group, 2,3,4-trimethylhexyl group, 2,3,5-trimethylhexyl group, 2,4,5-trimethylhexyl group, 3,4,5-trimethylhexyl group, 1,1-dimethylheptyl group, 1,2-dimethylheptyl group, 1,3-dimethylheptyl group, 1,4-dimethylheptyl group, 1,5-dimethylheptyl group, 1,6-dimethylheptyl group, 2, 2-Dimethylheptyl group, 2,3-dimethylheptyl group, 2,4-dimethylheptyl group, 2,5-dimethylheptyl group, 2,6-dimethylheptyl group, 3,3-dimethylheptyl group, 3,4- Dimethylheptyl group, 3,5-dimethylheptyl group, 3,6-dimethylheptyl group, 4,4-dimethylheptyl group, 4,5-dimethylheptyl group, 4,6-dimethylheptyl group, 5,5-dimethylheptyl group Group, 5,6-dimethylheptyl group, 6,6-dimethylheptyl group, 1,1,2-trimethylheptyl group, 1,1,3-trimethylheptyl group, 1,1,4-trimethylheptyl group, 1, 1,5-trimethylheptyl group, 1,1,6-trimethylheptyl group, 1,2,2-trimethylheptyl group, 2,2,3-trimethylheptyl group, 2,2,4-trimethylheptyl group, 2, 2,5-trimethylheptyl group, 2,2,6-trimethylheptyl group, 1,3,3-trimethylheptyl group, 2,3,3-trimethylheptyl group, 3,3,4-trimethylheptyl group, 3, 3,5-trimethylheptyl group, 3,3,6-trimethylheptyl group, 1,4,4-trimethylheptyl group, 2,4,4-trime Chilheptyl group, 3,4,4-trimethylheptyl group, 4,4,5-trimethylheptyl group, 4,4,6-trimethylheptyl group, 1,5,5-trimethylheptyl group, 2,5,5-trimethyl Heptyl group, 3,5,5-trimethylheptyl group, 4,5,5-trimethylheptyl group, 5,5,6-trimethylheptyl group, 1,6,6-trimethylheptyl group, 2,6,6-trimethyl Heptyl group, 3,6,6-trimethylheptyl group, 4,6,6-trimethylheptyl group, 5,6,6-trimethylheptyl group, 1,2,3-trimethylheptyl group, 1,2,4-trimethyl Heptyl group, 1,2,5-trimethylheptyl group, 1,2,6-trimethylheptyl group, 1,3,4-trimethylheptyl group, 1,3,5-trimethylheptyl group, 1,3,6-trimethyl Heptyl group, 1,4,5-trimethylheptyl group, 1,4,6-trimethylheptyl group, 2,3,4-trimethylheptyl group, 2,3,5-trimethylheptyl group, 2,3,6-trimethyl Heptyl group, 3,4,5-trimethylheptyl group, 3,4,6-trimethylheptyl group, 4,5,6-trimethylheptyl group, 1,1-dimethyloctyl group, 1,2-dimethyloctyl group, 1 , 3-Dimethyloctyl group, 1,4-dimethyloctyl group, 1,5-dimethyloctyl group, 1,6-dimethyloctyl group, 1,7-dimethyloctyl group, 2,2-dimethyloctyl group, 2,3 -Dimethyloctyl group, 2,4-dimethyloctyl group, 2,5-dimethyloctyl group, 2,6-dimethyloctyl group, 2,7-dimethyloctyl group, 3,3-dimethyloctyl group, 3,4-dimethyl Octyl group, 3,5-dimethyloctyl group, 3,6-dimethyloctyl group, 3,7-dimethyloctyl group, 4,4-dimethyloctyl group, 4,5-dimethyloctyl group, 4,6-dimethyloctyl group , 4,7-dimethyloctyl group, 5,5-dimethyloctyl group, 5,6-dimethyloctyl group, 5,7-dimethyloctyl group, 6,6-dimethyloctyl group, 6,7-dimethyloctyl group, 7 , 7-Dimethyloctyl group, 1,1,2-trimethyloctyl group, 1,1,3-trimethyloctyl group, 1,1,4-trimethyloctyl group, 1,1,5-trimethyloctyl group, 1,1 , 6-trimethyloctyl group, 1,1,7-trimethyloctyl group, 1,2,2-trimethyloctyl group, 2,2,3 -Trimethyloctyl group, 2,2,4-trimethyloctyl group, 2,2,5-trimethyloctyl group, 2,2,6-trimethyloctyl group, 2,2,7-trimethyloctyl group, 1,3,3 -Trimethyloctyl group, 2,3,3-trimethyloctyl group, 3,3,4-trimethyloctyl group, 3,3,5-trimethyloctyl group, 3,3,6-trimethyloctyl group, 3,3,7 -Trimethyloctyl group, 1,4,4-trimethyloctyl group, 2,4,4-trimethyloctyl group, 3,4,4-trimethyloctyl group, 4,4,5-trimethyloctyl group, 4,4,6 -Trimethyloctyl group, 4,4,7-trimethyloctyl group, 1,5,5-trimethyloctyl group, 2,5,5-trimethyloctyl group, 3,5,5-trimethyloctyl group, 4,5,5 -Trimethyloctyl group, 5,5,6-trimethyloctyl group, 5,5,7-trimethyloctyl group, 1,6,6-trimethyloctyl group, 2,6,6-trimethyloctyl group, 3,6,6 -Trimethyloctyl group, 4,6,6-trimethyloctyl group, 5,6,6-trimethyloctyl group, 6,6,7-trimethyloctyl group, 1,7,7-trimethyloctyl group, 2,7,7 -Trimethyloctyl group, 3,7,7-trimethyloctyl group, 4,7,7-trimethyloctyl group, 5,7,7-trimethyloctyl group, 6,7,7-trimethyloctyl group, 1,2,3 -Trimethyloctyl group, 1,2,4-trimethyloctyl group, 1,2,5-trimethyloctyl group, 1,2,6-trimethyloctyl group, 1,2,7-trimethyloctyl group, 1,3,4 -Trimethyloctyl group, 1,3,5-trimethyloctyl group, 1,3,6-trimethyloctyl group, 1,3,7-trimethyloctyl group, 1,4,5-trimethyloctyl group, 1,4,6 -Trimethyloctyl group, 1,4,7-trimethyloctyl group, 1,5,6-trimethyloctyl group, 1,5,7-trimethyloctyl group, 1,6,7-trimethyloctyl group, 2,3,4 -Trimethyloctyl group, 2,3,5-trimethyloctyl group, 2,3,6-trimethyloctyl group, 2,3,7-trimethyloctyl group, 2,4,5-trimethyloctyl group, 2,4,6 -Trimethyloctyl group, 2,4,7-trimethyloctyl group, 2,5,6-trimethyloctyl group, 2,5,7-trimethyloctyl group, 2, 6,7-trimethyloctyl group, 3,4,5-trimethyloctyl group, 3,4,6-trimethyloctyl group, 3,4,7-trimethyloctyl group, 3,5,6-trimethyloctyl group, 3, 5,7-trimethyloctyl group, 3,6,7-trimethyloctyl group, 4,5,6-trimethyloctyl group, 4,5,7-trimethyloctyl group, 4,6,7-trimethyloctyl group, 5, 6,7-trimethyloctyl group, 1,1-dimethylnonyl group, 1,2-dimethylnonyl group, 1,3-dimethylnonyl group, 1,4-dimethylnonyl group, 1,5-dimethylnonyl group, 1, 6-dimethylnonyl group, 1,7-dimethylnonyl group, 1,8-dimethylnonyl group, 2,2-dimethylnonyl group, 2,3-dimethylnonyl group, 2,4-dimethylnonyl group, 2,5- Dimethylnonyl group, 2,6-dimethylnonyl group, 2,7-dimethylnonyl group, 2,8-dimethylnonyl group, 3,3-dimethylnonyl group, 3,4-dimethylnonyl group, 3,5-dimethylnonyl Group, 3,6-dimethylnonyl group, 3,7-dimethylnonyl group, 3,8-dimethylnonyl group, 4,4-dimethylnonyl group, 4,5-dimethylnonyl group, 4,6-dimethylnonyl group, 4,7-dimethylnonyl group, 4,8-dimethylnonyl group, 5,5-dimethylnonyl group, 5,6-dimethylnonyl group, 5,7-dimethylnonyl group, 5,8-dimethylnonyl group, 6, 6-dimethylnonyl group, 6,7-dimethylnonyl group, 6,8-dimethylnonyl group, 7,7-dimethylnonyl group, 7,8-dimethylnonyl group, 8,8-dimethylnonyl group, 1,1, 2-trimethylnonyl group, 1,1,3-trimethylnonyl group, 1,1,4-trimethylnonyl group, 1,1,5-trimethylnonyl group, 1,1,6-trimethylnonyl group, 1,1,1 7-trimethylnonyl group, 1,1,8-trimethylnonyl group, 1,2,2-trimethylnonyl group, 2,2,3-trimethylnonyl group, 2,2,4-trimethylnonyl group, 2,2 5-trimethylnonyl group, 2,2,6-trimethylnonyl group, 2,2,7-trimethylnonyl group, 2,2,8-trimethylnonyl group, 1,3,3-trimethylnonyl group, 2,3 3-trimethylnonyl group, 3,3,4-trimethylnonyl group, 3,3,5-trimethylnonyl group, 3,3,6-trimethylnonyl group, 3,3,7-trimethylnonyl group, 3,3 8-trimethylnonyl group, 1,4,4-trimethyl Nonyl group, 2,4,4-trimethylnonyl group, 3,4,4-trimethylnonyl group, 4,4,5-trimethylnonyl group, 4,4,6-trimethylnonyl group, 4,4,7-trimethyl Nonyl group, 4,4,8-trimethylnonyl group, 1,5,5-trimethylnonyl group, 2,5,5-trimethylnonyl group, 3,5,5-trimethylnonyl group, 4,5,5-trimethyl Nonyl group, 5,5,6-trimethylnonyl group, 5,5,7-trimethylnonyl group, 5,5,8-trimethylnonyl group, 1,6,6-trimethylnonyl group, 2,6,6-trimethyl Nonyl group, 3,6,6-trimethylnonyl group, 4,6,6-trimethylnonyl group, 5,6,6-trimethylnonyl group, 6,6,7-trimethylnonyl group, 6,6,8-trimethyl Nonyl group, 1,7,7-trimethylnonyl group, 2,7,7-trimethylnonyl group, 3,7,7-trimethylnonyl group, 4,7,7-trimethylnonyl group, 5,7,7-trimethyl Nonyl group, 6,7,7-trimethylnonyl group, 7,7,8-trimethylnonyl group, 1,8,8-trimethylnonyl group, 2,8,8-trimethylnonyl group, 3,8,8-trimethyl Nonyl group, 4,8,8-trimethylnonyl group, 5,8,8-trimethylnonyl group, 6,8,8-trimethylnonyl group, 7,8,8-trimethylnonyl group, 1,2,3-trimethyl Nonyl group, 1,2,4-trimethylnonyl group, 1,2,5-trimethylnonyl group, 1,2,6-trimethylnonyl group, 1,2,7-trimethylnonyl group, 1,2,8-trimethyl Nonyl group, 1,3,4-trimethylnonyl group, 1,3,5-trimethylnonyl group, 1,3,6-trimethylnonyl group, 1,3,7-trimethylnonyl group, 1,3,8-trimethyl Nonyl group, 1,4,5-trimethylnonyl group, 1,4,6-trimethylnonyl group, 1,4,7-trimethylnonyl group, 1,4,8-trimethylnonyl group, 1,5,6-trimethyl Nonyl group, 1,5,7-trimethylnonyl group, 1,5,8-trimethylnonyl group, 1,6,7-trimethylnonyl group, 1,6,8-trimethylnonyl group, 1,7,8-trimethyl Nonyl group, 2,3,4-trimethylnonyl group, 2,3,5-trimethylnonyl group, 2,3,6-trimethylnonyl group, 2,3,7-trimethylnonyl group, 2,3,8-trimethyl Nonyl group, 2,4,5-trimethylnonyl group, 2,4,6-trimethylnonyl group, 2,4 , 7-trimethylnonyl group, 2,4,8-trimethylnonyl group, 2,5,6-trimethylnonyl group, 2,5,7-trimethylnonyl group, 2,5,8-trimethylnonyl group, 2,6 , 7-trimethylnonyl group, 2,6,8-trimethylnonyl group, 2,7,8-trimethylnonyl group, 3,4,5-trimethylnonyl group, 3,4,6-trimethylnonyl group, 3,4 , 7-trimethylnonyl group, 3,4,8-trimethylnonyl group, 3,5,6-trimethylnonyl group, 3,5,7-trimethylnonyl group, 3,5,8-trimethylnonyl group, 3,6 , 7-trimethylnonyl group, 3,6,8-trimethylnonyl group, 3,7,8-trimethylnonyl group, 4,5,6-trimethylnonyl group, 4,5,7-trimethylnonyl group, 4,5 , 8-trimethylnonyl group, 4,6,7-trimethylnonyl group, 4,6,8-trimethylnonyl group, 4,7,8-trimethylnonyl group, 5,6,7-trimethylnonyl group, 5,6 , 8-trimethylnonyl group, 5,7,8-trimethylnonyl group, 6,7,8-trimethylnonyl group, 1,1-dimethyldecyl group, 1,2-dimethyldecyl group, 1,3-dimethyldecyl group , 1,4-dimethyldecyl group, 1,5-dimethyldecyl group, 1,6-dimethyldecyl group, 1,7-dimethyldecyl group, 1,8-dimethyldecyl group, 1,9-dimethyldecyl group, 2 , 2-Dimethyldecyl group, 2,3-dimethyldecyl group, 2,4-dimethyldecyl group, 2,5-dimethyldecyl group, 2,6-dimethyldecyl group, 2,7-dimethyldecyl group, 2,8 -Dimethyldecyl group, 2,9-dimethyldecyl group, 3,3-dimethyldecyl group, 3,4-dimethyldecyl group, 3,5-dimethyldecyl group, 3,6-dimethyldecyl group, 3,7-dimethyl Decyl group, 3,8-dimethyldecyl group, 3,9-dimethyldecyl group, 4,4-dimethyldecyl group, 4,5-dimethyldecyl group, 4,6-dimethyldecyl group, 4,7-dimethyldecyl group , 4,8-dimethyldecyl group, 4,9-dimethyldecyl group, 5,5-dimethyldecyl group, 5,6-dimethyldecyl group, 5,7-dimethyldecyl group, 5,8-dimethyldecyl group, 5 , 9-dimethyldecyl group, 6,6-dimethyldecyl group, 6,7-dimethyldecyl group, 6,8-dimethyldecyl group, 6,9-dimethyldecyl group, 7,7-dimethyldecyl group, 7,8 -Dimethyldecyl group, 7,9-dimethyldecyl group, 8,8-dimethylde Examples thereof include a syl group, an 8,9-dimethyldecyl group, a 9,9-dimethyldecyl group, and the like. Among them, a 2,2-dimethylpropyl group and a 2,4,4-trimethylpentyl group are preferable, and a 2,4,4-trimethylpentyl group is particularly preferable.

Specific examples of the ester compound represented by the general formula (1) include, for example, 2- (1,3,3-trimethylbutyl) -5,7,7-trimethyl-1-octyl, 3, pivalate. 2- (1,3,3-trimethylbutyl) -5,7,7-trimethyl-1-octyl 3-dimethylbutanoate, 2- (1,3,3-trimethylbutyl) 3,5,5-trimethylhexanoic acid ) -5,7,7-trimethyl-1-octyl, 2- (1,3,3-trimethylbutyl) -5,7,7-trimethyl-1-octanoate 1,2-dimethylpropyl, 2- (1) , 3,3-trimethylbutyl) -5,7,7-trimethyl-1-octanoate 2,2-dimethylpropyl, 2- (1,3,3-trimethylbutyl) -5,7,7-trimethyl-1 -2,2-dimethylbutyl octanate, 2- (1,3,3-trimethylbutyl) -5,7,7-trimethyl-1-octanoate 2,3-dimethylbutyl, 2- (1,3,3) -Trimethylbutyl) -5,7,7-trimethyl-1-octanoic acid 3,3-dimethylbutyl, 2- (1,3,3-trimethylbutyl) -5,7,7-trimethyl-1-octanoic acid 3 , 3-Dimethyl-2-butyl, 2- (1,3,3-trimethylbutyl) -5,7,7-trimethyl-1-octanoate 4-methyl-2-pentyl, 2- (1,3,3) -Trimethylbutyl) -5,7,7-trimethyl-1-octanoic acid 1,2,2-trimethylpropyl, 2- (1,3,3-trimethylbutyl) -5,7,7-trimethyl-1-octane Acid 4,4-dimethyl-2-pentyl, 2- (1,3,3-trimethylbutyl) -5,7,7-trimethyl-1-octanoate 2,4-dimethyl-3-pentyl, 2- (1) , 3,3-trimethylbutyl) -5,7,7-trimethyl-1-octanoate 2-methyl-3-hexyl, 2- (1,3,3-trimethylbutyl) -5,7,7-trimethyl- 5-Methyl-3-heptyl 1-octanoate, 2- (1,3,3-trimethylbutyl) -5,7,7-trimethyl-1-octate 6-methyl-3-heptyl, 2- (1,1, 3,3-trimethylbutyl) -5,7,7-trimethyl-1-octanoate 2,2-dimethyl-3-hexyl, 2- (1,3,3-trimethylbutyl) -5,7,7-trimethyl -1-octanoate 2,5-dimethyl-3-hexyl, 2- (1,3,3-trimethylbutyl) -5,7,7-trimethyl-1-octanoate 2-methy Ru-3-octyl, 2- (1,3,3-trimethylbutyl) -5,7,7-trimethyl-1-octanoate 2,4-dimethyl-4-heptyl, 2- (1,3,3- Trimethylbutyl) -5,7,7-trimethyl-1-octanoate 2,6-dimethyl-4-heptyl, 2- (1,3,3-trimethylbutyl) -5,7,7-trimethyl-1- 3,5,5-trimethylhexyl octanate, 2- (1,3,3-trimethylbutyl) -5,7,7-trimethyl-1-octanoate 3,7-dimethyloctyl group,
2,6,8-trimethyl-4-nonyl, in particular 2- (1,3,3-trimethylbutyl) -5,7,7-trimethyl-1-octyl 3,5,5-trimethylcaproate. , 2- (1,3,3-trimethylbutyl) -5,7,7-trimethyl-1-octanoate 3,5,5-trimethylhexyl is preferred.

The above ester compound can also be used as a lubricating oil base oil for power transmission as a mixture of two or more kinds.

The method for producing an ester compound is not particularly limited as long as the compound is obtained.

For example, an esterification reaction of 2- (1,3,3-trimethylbutyl) -5,7,7-trimethyloctanol with the corresponding branched aliphatic monocarboxylic acid, 2- (1,3,3-trimethyl). Esterification reactions of butyl) -5,7,7-trimethyloctanoic acid with the corresponding branched chain fatty alcohols can be mentioned.

The acid value of the ester compound is preferably 0.1 mgKOH / g or less, more preferably 0.05 mgKOH / g or less. When the acid value is 0.1 mgKOH / g or less, the heat resistance of the ester compound itself tends to be further improved, and in such a preferable range, it also has a positive effect on the improvement of the heat resistant oxidation stability of the base oil of the present invention. .. As a method of reducing the acid value, a method of sufficiently advancing the reaction, a method of neutralizing and washing with an alkaline component in the post-treatment step (a step of washing with an alkaline aqueous solution (neutralization) and a step of washing with water), and the like. , A method of adsorption treatment with activated alumina and the like are exemplified.

The hydroxyl value of the ester compound is preferably 2 mgKOH / g or less, more preferably 1 mgKOH / g or less. When the hydroxyl value is 2 mgKOH / g or less, the hygroscopicity of the ester compound itself tends to be lower and the heat resistance tends to be further improved. It also has a positive effect on the improvement of. As a method for reducing the hydroxyl value, a method for sufficiently advancing the reaction and a method for distilling off the raw material alcohol component in the post-treatment step under reduced pressure (distilling excess distillable raw material under reduced pressure or normal pressure). Steps to be performed) and the like are exemplified.

The traction coefficient (60 ° C.) of the power transmission lubricating oil base oil is usually 0.080 or more, preferably 0.090 or more. The traction coefficient (60 ° C.) in the present specification and claims is a value measured by the method described in Examples described later.

The low temperature fluidity of the power transmission lubricating oil base oil can be evaluated, for example, by the pour point. The pour point of the lubricating oil base oil is usually −30 ° C. or lower, preferably −40 ° C. or lower, from the viewpoint of low temperature operability. In the present specification and claims, the pour point is a value measured by the method described in Examples described later.

The flash point of the power transmission lubricating oil base oil is usually 185 ° C. or higher, preferably 200 ° C. or higher, from the viewpoint of storage stability and handleability. If the temperature is lower than 185 ° C., there are many restrictions on handling due to ignition. The flash point in the present specification and claims is a value measured by the method described in Examples described later.

The power transmission lubricating oil base oil includes a power transmission lubricating oil base oil having a traction coefficient (60 ° C.) of 0.090 or more, a flow point of -30 ° C or less, and a ignition point of 185 ° C. or more, and a traction coefficient (60 ° C.) of 0. Power transmission lubricating oil base oil with 080 or more, flow point -40 ° C or less, ignition point 185 ° C or more, traction coefficient (60 ° C) 0.090 or more, flow point -30 ° C or less, ignition point 200 ° C or more Lubricating oil base oil for power transmission is preferable, and in particular, a lubricating oil base oil for power transmission having a traction coefficient (60 ° C.) of 0.090 or more, a flow point of -40 ° C. or less, and an ignition point of 185 ° C. or more, and a traction coefficient (60 ° C.) of 0. Power transmission lubricating oil base oil with 090 or more, flow point -30 ° C or less, ignition point 200 ° C or more, traction coefficient (60 ° C) 0.090 or more, flow point -40 ° C or less, ignition point 185 ° C or more Lubricating oil base oil for power transmission is more preferable, and particularly preferable is a lubricating oil base oil for power transmission having a traction coefficient (60 ° C.) of 0.090 or more, a flow point of −40 ° C. or less, and a ignition point of 200 ° C. or more.

The lubricating oil base oil for power transmission of the present invention has a high traction coefficient and ignition point, and has good low-temperature fluidity, and is therefore suitable as a lubricating oil base oil for power transmission, particularly a lubricating oil base oil for traction drive. Used for.

The lubricating oil base oil for power transmission of the present invention can include other base oils that can be used in combination (hereinafter referred to as "combined base oil"). That is, the lubricating oil base oil for power transmission of the present invention includes only the ester compound and a mixture of the ester compound and the combined base oil. Hereinafter, the lubricating oil base oil for power transmission may be referred to as "base oil".

The combined base oil includes mineral oil (hydrocarbon oil obtained by refining petroleum), poly-α-olefin, polybutene, alkylbenzene, alkylnaphthalene, alicyclic hydrocarbon oil, animal and vegetable oil, and organic acid ester (in the present invention). (Excluding such ester compounds), base oils such as polyalkylene glycols, polyvinyl ethers, polyphenyl ethers, alkylphenyl ethers and silicone oils can be mentioned. At least one of these can be used in combination as appropriate.

Mineral oils, solvent refined mineral oils, hydrotreated mineral oil, but wax isomerized oil and the like, is usually, 100 kinematic viscosity at ℃ is 1 to 25 mm ² / s, in the range of preferably 2 to 20 mm ² / s Things are used.

Examples of the poly-α-olefin include α-olefins having 2 to 16 carbon atoms (for example, ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene). Etc.), wherein the kinematic viscosity at 100 ° C. is 1 to 25 mm ² / s and the viscosity index is 100 or more, and the kinematic viscosity at 100 ° C. is 1.5 to ^{20 mm 2} It is preferable that the viscosity index is 120 or more at / s.

Examples of polybutene include those obtained by polymerizing isobutylene and those obtained by copolymerizing isobutylene with normal butylene, and generally include those having a kinematic viscosity of ² to 40 mm 2 / s at 100 ° C.

Examples of the alkylbenzene include monoalkylbenzene, dialkylbenzene, trialkylbenzene, tetraalkylbenzene and the like having a molecular weight of 200 to 450 substituted with a linear or branched alkyl group having 1 to 40 carbon atoms.

Examples of the alkylnaphthalene include monoalkylnaphthalene substituted with a linear or branched alkyl group having 1 to 30 carbon atoms, dialkylnaphthalene and the like.

Examples of the alicyclic hydrocarbon oil include naphthenic hydrocarbon oils and the like, which generally have a kinematic viscosity of 1 to 40 mm ² / s at 100 ° C.

Examples of animal and vegetable oils include beef fat, pork fat, palm oil, palm oil, rapeseed oil, castor oil, sunflower oil and the like.

Examples of the organic acid ester include fatty acid monoesters (excluding the ester compounds according to the present invention), aliphatic dibasic acid diesters, aliphatic dihydric alcohol diesters, polyol esters and other esters.

The fatty acid monoester is an ester of an aliphatic linear or branched monocarboxylic acid having 5 to 22 carbon atoms and a linear or branched saturated or unsaturated fatty alcohol having 3 to 22 carbon atoms. Can be mentioned. However, the ester compound according to the present invention is excluded.

Examples of the aliphatic dibasic acid diester include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelli acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonamethylenedicarboxylic acid, and 1,10-deca. Examples thereof include a diester of an aliphatic dibasic acid such as methylenedicarboxylic acid or an anhydride thereof and a linear or branched saturated or unsaturated aliphatic alcohol having 3 to 22 carbon atoms.

Examples of the aliphatic dihydric alcohol diester and the polyol ester include neopentyl glycol, 2,2-diethylpropanediol, 2-butyl-2-ethylpropanediol, trimethylolethane, trimethylolpropane, pentaerythritol, ditrimethylolpropane and di. Neopentyl-type polyols such as pentaerythritol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octane Glycol, 1,9-nonanediol, 1,10-decanediol, 1,2-propanediol, 2-methyl-1,3-propanediol, 1,3-butanediol, 2-methyl-1,4-butane Glycol, 1,4-pentanediol, 2-methyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,5-hexanediol, 2-methyl-1,6-hexanediol, 3 -Methyl-1,6-hexanediol, 1,6-heptanediol, 2-methyl-1,7-heptanediol, 3-methyl-1,7-heptanediol, 4-methyl-1,7-heptanediol, 1,7-octanediol, 2-methyl-1,8-octanediol, 3-methyl-1,8-octanediol, 4-methyl-1,8-octanediol, 1,8-nonanediol, 2-methyl -1,9-nonanediol, 3-methyl-1,9-nonanediol, 4-methyl-1,9-nonanediol, 5-methyl-1,9-nonanediol, 2-ethyl-1,3-hexane Non-neopentyl-type polyols such as diols, 2,4-diethyl-1,5-pentanediol, glycerin, polyglycerin, and sorbitol, and linear and / or branched-chain saturated or unsaturated with 3 to 22 carbon atoms. It is possible to use full esters with the fatty acids of.

Other esters include polymerized fatty acids such as dimer acid and hydrogenated dimer acid, or hydroxy fatty acids such as condensed castor oil fatty acid and hydrogenated condensed castor oil fatty acid, and linear or branched chains having 3 to 22 carbon atoms. Examples include esters with saturated or unsaturated fatty acids.

Examples of the polyalkylene glycol include a ring-opening polymer of an alcohol and a linear or branched alkylene oxide having 2 to 4 carbon atoms. Examples of the alkylene oxide include ethylene oxide, propylene oxide, and butylene oxide, and a polymer using one of these or a copolymer using a mixture of two or more can be used. Further, a compound in which the hydroxyl groups at one end or both ends are etherified can also be used. The kinematic viscosity of the polymer is preferably 5 to 1000 mm ² / s (40 ° C), more preferably 5 to 500 mm ² / s (40 ° C).

The polyvinyl ether is a compound obtained by polymerizing a vinyl ether monomer, and the monomers are methyl vinyl ether, ethyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, sec-butyl vinyl ether, tert-butyl vinyl ether, and n-pentyl vinyl ether. , N-Hexyl vinyl ether, 2-methoxyethyl vinyl ether, 2-ethoxyethyl vinyl ether and the like. The kinematic viscosity of the polymer is preferably 5 to 1000 mm ² / s (40 ° C), more preferably 5 to 500 mm ² / s (40 ° C).

Examples of the polyphenyl ether include compounds having a structure in which the meta positions of two or more aromatic rings are connected by an ether bond or a thioether bond, and specific examples thereof include bis (m-phenoxyphenyl) ether and m-bis (. Examples thereof include m-phenoxyphenoxy) benzene and thioethers (commonly known as C-ether) in which one or more of these oxygens are replaced with sulfur.

Examples of the alkyl phenyl ether include compounds in which polyphenyl ether is substituted with a linear or branched alkyl group having 6 to 18 carbon atoms, and an alkyl diphenyl ether substituted with one or more alkyl groups is particularly preferable.

Examples of the silicone oil include modified silicones such as dimethyl silicone and methyl phenyl silicone, as well as long-chain alkyl silicones and fluorosilicones.

The content of the ester compound in the power transmission lubricating oil base oil of the present invention is usually 70% by mass or more, preferably 90% by mass or more.

The content of the combined base oil in the power transmission lubricating oil base oil of the present invention is usually 30% by mass or less, preferably 10% by mass or less.

The present invention also provides a power transmission lubricating oil containing the power transmission lubricating oil base oil. In order to improve the performance of the power transmission lubricating oil, for example, antioxidants, metal detergents, ashless dispersants, oily agents, anti-wear agents, extreme pressure agents, metal deactivators, and anti-corrosion agents are used as base oils. It is also possible to appropriately add at least one of additives such as a rust agent, a viscosity index improver, a flow point lowering agent, a defoaming agent, a hydrolysis inhibitor, a thickener, a corrosion inhibitor, and a hue stabilizer. .. The blending amounts thereof are not particularly limited as long as the effects of the present invention are exhibited, but specific examples thereof are shown below.

Antioxidants include 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-p-cresol, 4,4'-methylenebis (2,6-di-tert-butylphenol), 4, 4'-butylidenebis (3-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 2,2'-methylenebis (4-methyl-6-tert-butylphenol) ), 4,4'-Isopropylidenebisphenol, 2,4-dimethyl-6-tert-butylphenol, tetrakis [methylene-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane, 1 , 1,3-Tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-) 4-Hydroxybenzyl) benzene, 2,2'-dihydroxy-3,3'-di (α-methylcyclohexyl) -5,5'-dimethyl-diphenylmethane, 2,2'-isobutylidenebis (4,6--) Dimethylphenol), 2,6-bis (2'-hydroxy-3'-tert-butyl-5'-methylbenzyl) -4-methylphenol, 1,1'-bis (4-hydroxyphenyl) cyclohexane, 2, 5-Di-tert-amylhydroquinone, 2,5-di-tert-butylhydroquinone, 1,4-dihydroxyanthraquinone, 3-tert-butyl-4-hydroxyanisole, 2-tert-butyl-4-hydroxyanisole, 2 , 4-Dibenzoylresorcinol, 4-tert-butylcatechol, 2,6-di-tert-butyl-4-ethylphenol, 2-hydroxy-4-methoxybenzophenone, 2,4-dihydroxybenzophenone, 2,2'- Dihydroxy-4-methoxybenzophenone, 2,4,5-trihydroxybenzophenone, α-tocopherol, bis [2- (2-hydroxy-5-methyl-3-tert-butylbenzyl) -4-methyl-6-tert- Butylphenyl] terephthalate, triethylene glycol bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5-di-tert) -Butyl-4-hydroxyphenyl) propionate], diphenylamine, mono Butyl (including linear and branched chains) diphenylamine, monopentyl (including linear and branched chains) diphenylamine, monohexyl (including linear and branched chains) diphenylamine, monoheptyl (including linear and branched chains) diphenylamine, mono Monoalkyldiphenylamines such as octyl (including linear and branched) diphenylamines, especially mono (C _4- C ₉ alkyl) diphenylamines (ie, one of the two benzene rings of diphenylamine is an alkyl group, especially C _4- C _9). Diphenylamine mono-substituted with an alkyl group), dibutyl (including linear and branched chains) diphenylamine, dipentyl (including linear and branched chains) diphenylamine, dihexyl (including linear and branched chains) diphenylamine, diheptyl (directly) and branched chain containing) diphenylamine, including dioctyl (straight and branched chain) diphenylamine, including dinonyl (linear and branched) di such diphenylamine (alkylphenyl) amines, in particular, di (C ₄ -C ₉ alkylphenyl) amine (i.e., each of the two benzene rings of diphenylamine, alkyl group, especially a diphenylamine which is mono-substituted by C ₄ -C ₉ alkyl group, those two alkyl groups are identical), Di (mono-C _4- C ₉ alkylphenyl) amine, in which the alkyl group on one benzene ring is different from the alkyl group on the other benzene ring, di (di-C _4- C ₉ alkylphenyl) amine. At least one of the four alkyl groups on the two benzene rings differs from the remaining alkyl groups: N-phenyl-1-naphthylamine, N-phenyl-2-naphthylamine, 4-octylphenyl-1. -Nuftylamines such as naphthylamine, 4-octylphenyl-2-naphthylamine, p-phenylenediamine, N-phenyl-N'-isopropyl-p-phenylenediamine, N-phenyl-N'-(1,3-dimethylbutyl) Examples thereof include phenylenediamines such as −p-phenylenediamine.

Among these, in particular, dioctyl (including linear and branched chains) diphenylamine, dinonyl (including linear and branched chains) diphenylamine, N-phenyl-1-naphthylamine, di (n-dodecyl) thiodipropionic acid, and thiodi Examples thereof include thiodipropionic acid esters such as di (n-octadecyl) propionic acid, and sulfur compounds such as phenothiazine. These antioxidants can be used alone or in combination of two or more as appropriate. When an antioxidant is used, it is usually desirable to add 0.01 to 5% by mass, preferably about 0.05 to 3% by mass, based on the base oil.

Here, in the present specification and claims, the blending amount of the additive is used by using the expression "relative to the base oil" such as "0.01 to 5% by mass with respect to the base oil". May specify the range of. The "base oil" used in this case is a base oil consisting only of the ester compound represented by the general formula (1) or a mixture of the ester compound represented by the general formula (1) and the combined base oil according to the present invention. It is used in the sense of any of the base oils. Further, in the example of "0.01 to 5% by mass with respect to the base oil", it is synonymous with the meaning of 0.01 to 5 parts by mass with respect to 100 parts by mass of the base oil.

Examples of the metal detergent include Ca-petroleum sulphonate, perbasic Ca-petroleum sulphonate, Ca-alkylbenzene sulphonate, perbasic Ca-alkylbenzene sulphonate, Ba-alkylbenzene sulphonate, and hyperbasic Ba-alkylbenzene sulphonate. Phonate, Mg-alkylbenzene sulphonate, hyperbasic Mg-alkylbenzene sulphonate, Na-alkylbenzene sulphonate, hyperbasic Na-alkylbenzene sulphonate, Ca-alkylnaphthalen sulphonate, hyperbasic Ca- Metal sulphonate such as alkylnaphthalene sulphonate, metal sulphonate such as Ca-phenate, hyperbasic Ca-phenate, Ba-phenate, metal phenate such as hyperbasic Ba-phenate, metal salicylate such as Ca-salicylate, hyperbasic Ca-salicylate. , Ca-phosphonate, hyperbasic Ca-phosphonate, Ba-phosphonate, metal phosphonate such as hyperbasic Ba-phosphonate, hyperbasic Ca-carboxylate and the like can be used. .. When a metal detergent is used, it is usually desirable to add about 1 to 10% by mass, preferably about 2 to 7% by mass, based on the base oil.

Examples of the ashless dispersant include polyalkenylsuccinimide, polyalkenylsuccinamide, polyalkenylbenzylamine, polyalkenylsuccinate and the like. These ashless dispersants may be used alone or in combination, and when they are used, it is usually desirable to add 1 to 10% by mass, preferably about 2 to 7% by mass, based on the base oil.

Examples of the oily agent include aliphatic saturated and unsaturated monocarboxylic acids such as stearic acid and oleic acid, polymerized fatty acids such as dimer acid and hydrogenated dimer acid, hydroxy fatty acids such as ricinoleic acid and 12-hydroxystearic acid, and lauryl alcohols. Aliper saturated and unsaturated monoalcohols such as oleyl alcohols, aliphatic saturated and unsaturated monoamines such as stearylamine and oleylamine, aliphatic saturated and unsaturated monocarboxylic acid amides such as lauric acid amides and oleic acid amides, batyl alcohols, Glycerin ethers such as chimil alcohol and ceracyl alcohol, alkyl or alkenyl polyglyceryl ethers such as lauryl polyglycerin ether and oleyl polyglyceryl ether, alkyl or alkenyl amines such as di (2-ethylhexyl) monoethanolamine and diisotridecyl monoethanolamine. Poly (alkylene oxide) adducts and the like are exemplified. These oily agents may be used alone or in combination, and when they are used, they are usually added in an amount of 0.01 to 5% by mass, preferably about 0.1 to 3% by mass, based on the base oil. Is desirable.

As anti-wear / extreme pressure agents, tricresyl phosphate, cresyl diphenyl phosphate, alkyl phenyl phosphates, tributyl phosphate, phosphoric acid esters such as dibutyl phosphate, tributyl phosphite, dibutyl phosphite, triisopropyl phosphite, etc. Phosphorus-based substances such as phosphites and amine salts thereof, sulfided fatty acids such as sulfide oils and fats and oleic acid sulfide, sulfur-based substances such as dibenzyl disulfide, olefin sulfide and dialkyl disulfide, Zn-dialkyldithiophosphate, Zn- Examples thereof include organic metal compounds such as dialkyl dithiophosphate, Mo-dialkyldithiophosphate, and Mo-dialkyldithiocarbamate. These anti-wear agents may be used alone or in combination, and when used, they are usually added in an amount of 0.01 to 10% by mass, preferably about 0.1 to 5% by mass, based on the base oil. Is desirable.

Examples of the metal deactivator include benzotriazole-based compounds, thiadiazole-based compounds, and gallic acid ester-based compounds. These metal deactivating agents may be used alone or in combination, and when used, they are usually 0.01 to 0.4% by mass, preferably 0.01 to 0.2, based on the base oil. It is desirable to add about% by mass.

Anti-rust agents include alkyl or alkenyl succinic acid derivatives such as dodecenyl succinic acid half ester, octadecenyl succinic anhydride, dodecenyl succinic acid amide, sorbitan monooleate, glycerin monooleate, pentaerythritol monooleate and the like. Alcohol Partial Ester, Ca-Petite Sulfonate, Ca-alkylbenzene Sulfonate, Ba-alkylbenzene Sulfonate, Mg-alkylbenzene Sulfonate, Na-alkylbenzene Sulfonate, Zn-alkylbenzene Sulfonate, Ca-alkylnaphthalenzul Examples thereof include metal sulfonates such as phonates, rosinamines, amines such as N-oleylzalkosine, and dialkylphosphiteamine salts. These rust preventives may be used alone or in combination, and when they are used, they are usually added in an amount of 0.01 to 5% by mass, preferably about 0.05 to 2% by mass, based on the base oil. Is desirable.

Examples of the viscosity index improver include olefin copolymers such as polyalkyl methacrylate, polyalkyl styrene, polybutene, ethylene-propylene copolymer, styrene-diene copolymer, and styrene-maleic anhydride copolymer. .. These viscosity index improvers may be used alone or in combination, and when they are used, they are usually added in an amount of 0.1 to 15% by mass, preferably about 0.5 to 7% by mass, based on the base oil. It is desirable to do.

Examples of the pour point lowering agent include a condensate of chlorinated paraffin and alkylnaphthalene, a condensate of chlorinated paraffin and phenol, and the above-mentioned viscosity index improvers such as polyalkylmethacrylate, polyalkylstyrene, and polybutene. These pour point lowering agents may be used alone or in combination, and when they are used, they are usually added in an amount of 0.01 to 5% by mass, preferably about 0.1 to 3% by mass, based on the base oil. It is desirable to do.

Liquid silicone is suitable as the defoaming agent, and when it is used, the amount added thereof is usually about 0.0005 to 0.01% by mass with respect to the base oil.

Examples of the hydrolysis inhibitor include alkyl glycidyl ethers, alkyl glycidyl esters, alkylene glycol glycidyl ethers, alicyclic epoxys, epoxy compounds such as phenyl glycidyl ether, di-tert-butyl carbodiimide, 1,3-di-. A carbodiimide compound such as p-tolylcarbodiimide can be used, and it is usually about 0.05 to 2% by mass with respect to the base oil.

A "grease" can be obtained by appropriately combining a thickener with the power transmission lubricating oil base oil of the present invention.

Examples of the thickener include a metal soap-based thickener, a complex metal soap-based thickener, and a non-soap-based thickener.

Examples of the metal soap-based thickener include sodium soap, calcium soap, and lithium soap, in particular, an aliphatic carboxylic acid lithium salt having a hydroxyl group such as lithium-12-hydroxystearate, and an aliphatic carboxylic acid lithium salt such as lithium stearate. Or a mixture thereof and the like are exemplified.

Examples of the complex metal soap-based thickener include a complex of a monovalent aliphatic carboxylic acid metal salt having a hydroxyl group and a divalent aliphatic carboxylic acid metal salt, and specifically, complex lithium soap and the like. Composite aluminum soap is exemplified.

Non-soap-based thickeners include bentonite, silica airgel, sodium terephthalamate, polytetrafluoroethylene, boron nitride, and urea compounds (alicyclic, aromatic, aliphatic, diurea, triurea, tetraurea, and urea-urethane compounds). Etc.), etc. are exemplified.

Among the above, lithium soap, lithium complex soap, and urea compounds are suitable as thickeners from the viewpoints of heat resistance, water resistance, and shear stability, and urea compounds are particularly preferable.

These thickeners can be used alone or in combination of two or more as appropriate, and the amount added thereof is not particularly limited as long as a predetermined effect is obtained.

Examples of the corrosion inhibitor include sodium sulfonate and sorbitan ester, which are usually added in an amount of about 0.1 to 3.0% by mass with respect to the base oil.

Examples of the hue stabilizer include substituted hydroquinone and furfural azine, which are usually added in an amount of about 0.01 to 0.1% by mass with respect to the base oil.

As described above, the power transmission lubricating oil of the present invention thus obtained is suitable as a traction drive lubricating oil because it contains a base oil having a high traction coefficient and a high ignition point and excellent low temperature fluidity.

The power transmission lubricating oil base oil of the present invention and the ester compound represented by the general formula (1) can be added to the power transmission lubricating oil (particularly, the traction drive lubricating oil) to obtain the power transmission lubricating oil. The traction coefficient can be improved. Therefore, it can be used as a traction coefficient improving agent.

The lubricating oil for power transmission of the present invention has high power transmission ability, less generation of vibration and noise, and a high ignition point. Therefore, it is used as a lubricating oil for a traction drive, that is, a power transmission device composed of two or more rotating bodies. be able to. Examples of the device that employs the traction drive include motors such as automobiles, ships, aircraft, precision equipment, and robots, transmissions, generators, and reduction gears.

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. In addition, the physical characteristics and chemical characteristics of the lubricating oil base oil and the lubricating oil composition in each example were evaluated by the following methods. Reagents were used for compounds not specifically mentioned.

<Compounds used>
2- (1,3,3-trimethylbutyl) -5,7,7-trimethyl-1-octanoic acid: "Product name" Stearic Acid "manufactured by Tokyo Chemical Industry Co., Ltd."
2- (1,3,3-trimethylbutyl) -5,7,7-trimethyl-1-octanol: manufactured by Nissan Chemical Industries, Ltd. Product name "Fineoxocol 180"
3,5,5-trimethyl-1-hexaneic acid: KH Neochem Co., Ltd. Product name "Kyowanoic-N"
3,5,5-trimethyl-1-hexanol: KH Neochem Co., Ltd. Product name "Nonanol"
1-Pelargonic acid: Made by Tokyo Chemical Industry Co., Ltd. Product name "Nonanoic Acid"
2-Hexyl-1-decanol: Made by Tokyo Chemical Industry Co., Ltd. Product name "2-Hexyl-1-decanol"
Diisodecyl adipic acid: Made by Shin Nihon Rika Co., Ltd. Product name "Sun Sizar DIDA"
Mineral oil Y: Made by NOF CORPORATION Product name "Polybutene 0N"

(A) Acid value (AV)
Measured according to JIS K2501 (2003). The detection limit is 0.01 KOHmg / g.

(B) Hydroxyl value (OHV)
Measured according to JIS K0070 (1992). The detection limit is 0.1 KOHmg / g.

[Measurement of physical properties of lubricating oil base oil]
(C) Traction coefficient The maximum traction coefficient when tested with the following equipment and conditions was measured and used as the traction coefficient (60 ° C.).
[Measurement condition]
Equipment: Ball-on-ring type friction tester (TE54 type manufactured by Phoenix Tribology)
Specimen shape: Upper test piece (ball with a diameter of 25 mm), lower test piece (ring with a diameter of 50 mm)
Specimen material: SUJ2
Slip rate: 5%
Sample temperature: 60 ° C
Load: 150N
<Evaluation of traction coefficient>
A: 0.090 or more B: 0.080 or more and less than 0.090 C: less than 0.080

(D) Low temperature fluidity test (pour point)
The pour point was measured according to JIS-K-2269 (1987).
<Evaluation of low temperature fluidity>
A: -40 ° C or less B: Over -40 ° C -30 ° C or less C: Over -30 ° C

(E) Flash point Measured according to JIS K2265 (Cleveland open type).
<Evaluation of flash point>
A: 200 ° C or higher B: 185 ° C or higher and lower than 200 ° C C: 185 ° C (f) Evaluation of lubricating oil base oil for power transmission Evaluation of lubricating oil base oil for power transmission includes evaluation of traction coefficient and low temperature fluidity. In the results of the evaluation of and the evaluation of the ignition point, if C is 1 or more, it is unsuitable, if B is 2 or less (other evaluation is A), it is good, and if B is 1 or less (other evaluation is A). It is evaluated as particularly good.

[Example 1]
278.5 g (1.76 mol) of 3,5,5-trimethyl-1-hexaneic acid as carboxylic acid in a 1 liter four-necked flask equipped with a stirrer, a thermometer, and a water fractionator with a condenser, alcohol. 2- (1,3,3-trimethylbutyl) -5,7,7-trimethyl-1-octanol 432.8 g (1.60 mol), 0.7 g tin oxide as an esterification catalyst, and 30 g xylene as an entrainer. After charging and replacing the inside of the flask with nitrogen, the temperature was gradually raised to 230 ° C. The esterification reaction was carried out while adjusting the degree of decompression so that xylene was refluxed, and removing the generated water distilled out with the theoretical amount of produced water (28.8 g) by a fractional distillation receiver. After completion of the reaction, the remaining 3,5,5-trimethyl-1-hexaneic acid and xylene were removed by distillation under reduced pressure to obtain an esterified crude product. Then, after neutralizing with an aqueous solution of caustic soda having an equivalent amount of 1.5 times the acid value of the obtained crude esterified product, washing with water was repeated until it became neutral. Magnesium sulfate was added to the obtained crude esterified product to dehydrate it, and then magnesium sulfate was removed by filtration to obtain 2- (1,3,3-trimethylbutyl) of 3,5,5-trimethyl-1-hexaneate. -5,7,7-trimethyl-1-octyl 545.4 g (1.33 mol) was obtained. The acid value of the obtained compound was 0.01 mgKOH / g or less, and the hydroxyl value was 1 mgKOH / g or less. Table 1 shows each physical property when the compound is evaluated as a lubricating oil base oil (A) for power transmission.

[Example 2]
Add 3,5,5-trimethyl-1-hexaneic acid to 2- (1,3,3-trimethylbutyl) -5,7,7-trimethyl-1-octanoic acid 455.2 g (1.60 mol), 2- Example 1 except that (1,3,3-trimethylbutyl) -5,7,7-trimethyl-1-octanol was changed to 277.0 g (1.92 mol) of 3,5,5-trimethyl-1-hexanol. The esterification reaction was carried out in the same manner as in the above. After completion of the reaction, the remaining 3,5,5-trimethyl-1-hexanol and xylene were removed by distillation under reduced pressure to obtain an esterified crude product. Then, after neutralizing with an aqueous solution of caustic soda having an equivalent amount of 1.5 times the acid value of the obtained crude esterified product, washing with water was repeated until it became neutral. Magnesium sulfate is added to the obtained crude esterified product to dehydrate it, and then magnesium sulfate is removed by filtration to remove 2- (1,3,3-trimethylbutyl) -5,7,7-trimethyl-1-octane. 558.6 g (1.36 mol) of acid 3,5,5-trimethyl-1-hexyl was obtained. The acid value of the obtained compound was 0.01 mgKOH / g or less, and the hydroxyl value was 1 mgKOH / g or less. Table 1 shows each physical property when the compound is evaluated as a lubricating oil base oil (B) for power transmission.

[Comparative Example 1]
Table 2 shows the physical property values when diisodecyl adipate was evaluated as the lubricating oil base oil (a) for power transmission.

[Comparative Example 2]
Table 2 shows each physical property when the mineral oil Y is evaluated as the lubricating oil base oil (b) for power transmission.

[Comparative Example 3]
In the same manner as in Example 1 except that 3,5,5-trimethyl-1-hexaneic acid was changed to 278.5 g (1.76 mol) of 1-nonanoic acid, 1-nonanoic acid 2- (1,3). 3-trimethylbutyl) -5,7,7-trimethyl-1-octyl 552.0 g (1.34 mol) was obtained. The acid value of the obtained compound was 0.01 mgKOH / g or less, and the hydroxyl value was 1 mgKOH / g or less. Table 2 shows each physical property when the compound is evaluated as a lubricating oil base oil (c) for power transmission.

[Comparative Example 4]
The amount of 3,5,5-trimethyl-1-hexaneic acid charged was 299.4 g (1.89 mol), and 2- (1,3,3-trimethylbutyl) -5,7,7-trimethyl-1-octanol. In the same manner as in Example 1 except that 2-hexyl-1-decanol was changed to 417.0 g (1.72 mol), 3,5,5-trimethyl-1-hexanoate 2-hexyl-1- A decyl 566.0 g (1.48 mol) was obtained. The acid value of the obtained compound was 0.01 mgKOH / g or less, and the hydroxyl value was 1 mgKOH / g or less. Table 2 shows each physical property when the compound is evaluated as a lubricating oil base oil (d) for power transmission.

From Table 1, the power transmission lubricating oil base oil of the present invention described in Example 1 and Example 2 has a high traction coefficient of 0.090 or more, a pour point of −40 ° C. or less, and a flash point. It can be seen that the coefficient is as high as 185 ° C or higher.

Since the power transmission lubricating oil base oil of the present invention has a high traction coefficient, a high ignition point and good low temperature fluidity, the power transmission lubricating oil base oil for automobiles, ships, aircraft and precision equipment (particularly). It can be suitably used as a lubricating oil base oil for traction drive).

Claims (5)

General formula (1)

[In the formula, R ¹ is a branched chain alkyl group having 4 to 12 carbon atoms (the branched chain alkyl group is a linear alkyl group which is a main chain and has two or three or more carbon atoms bonded thereto. Represents (consisting of 1 to 3 alkyl groups (branches)), where X is the following (a) or (b).

Represents. ]
Lubricating oil base oil for power transmission containing an ester compound represented by. The lubricating oil base oil for power transmission according to claim 1, wherein the ester compound is an ester compound represented by the following general formula (2) or general formula (3).

The power transmission lubricating oil base oil according to claim 1 or 2, wherein the content of the ester compound represented by the general formula (1) is 70% by mass or more in the power transmission lubricating oil base oil. The power transmission lubricating oil base oil according to any one of claims 1 to 3, wherein the power transmission lubricating oil base oil is a traction drive lubricating oil base oil. A power transmission lubricating oil containing the power transmission lubricating oil base oil according to any one of claims 1 to 4.