WO2023190238A1

WO2023190238A1 - Lubricant

Info

Publication number: WO2023190238A1
Application number: PCT/JP2023/011986
Authority: WO
Inventors: 知晃岡野; 康平吉田; 聡中島; 俊亮小矢
Original assignee: 出光興産株式会社
Priority date: 2022-03-31
Filing date: 2023-03-24
Publication date: 2023-10-05
Also published as: TW202344674A; JP2023151663A

Abstract

A lubricant having a halogen atom content of 0.1 mass% or less and containing a deep eutectic solvent composed of a hydrogen bond acceptor and a hydrogen bond donor, whereby there is provided a lubricant that contains a carbon-neutral component, exhibits excellent lubricity, and has low metal corrosiveness.

Description

lubricant

The present invention relates to a lubricant.

In recent years, as environmental awareness has increased, efforts to move away from petrochemicals have been accelerated, as exemplified by declarations of carbon neutrality. However, in the lubricating oil field, mineral oils obtained by refining petroleum fractions continue to be widely used as lubricant base oils used as base materials for various lubricating oil compositions, and studies on carbon-neutral materials are ongoing. It is desired.

Patent Document 1 discloses a lubricating oil composition containing an ionic liquid as a component.

JP 2021-161309 Publication

However, there is a concern that the lubricating oil composition containing the ionic liquid described in Patent Document 1 may be corrosive to metals. Thus, it has been difficult to achieve both carbon neutrality and low corrosion resistance.

The present invention was made in view of the above problems, and an object of the present invention is to provide a lubricant that contains a carbon-neutral component, exhibits good lubricity, and is less corrosive to metals.

The present inventors have discovered that a lubricant containing a deep eutectic solvent consisting of a hydrogen bond acceptor and a hydrogen bond donor and having a halogen atom content of 0.1% by mass or less can solve the above problems. , completed the present invention.
That is, the present invention provides the following [1] to [3].
[1] A lubricant containing a deep eutectic solvent consisting of a hydrogen bond acceptor and a hydrogen bond donor, and having a halogen atom content of 0.1% by mass or less.
[2] A lubrication method using the lubricant according to [1] above.
[3] The method for producing a lubricant according to [1] above, comprising the step of mixing a hydrogen bond acceptor and a hydrogen bond donor to obtain a deep eutectic solvent.

According to the present invention, it is possible to provide a lubricant that contains a carbon-neutral component, exhibits good lubricity, and is less corrosive to metals.

A photograph of the surface of the steel plate (SPCC-SD) after performing the reciprocating friction test in Example 1. A photograph of the surface of the steel plate (SPCC-SD) after performing the reciprocating friction test in Comparative Example 1. A photograph of the surface of the steel plate (SPCC-SD) after performing the reciprocating friction test in Comparative Example 2. A photograph of the surface of the steel plate (SPCC-SD) after performing the reciprocating friction test in Comparative Example 3.

In this specification, the lower and upper limits described in stages for preferred numerical ranges (for example, ranges of content, etc.) can be independently combined. For example, from the description "preferably 10 to 90, more preferably 30 to 60," the "preferred lower limit (10)" and "more preferable upper limit (60)" are combined to give "10 to 60." You can also do that. Similarly, in this specification, the terms "more than", "less than", "less than", and "greater than" in the description of numerical ranges are numerical values that can be combined arbitrarily.

[lubricant]
The lubricant of this embodiment contains a deep eutectic solvent consisting of a hydrogen bond acceptor and a hydrogen bond donor, and has a halogen atom content of 0.1% by mass or less.
If the content of halogen atoms in the lubricant exceeds 0.1% by mass, the corrosivity to metals will increase.
Each component contained in the lubricant of this embodiment will be explained below.

<Deep eutectic solvent>
The deep eutectic solvent contained in the lubricant of this embodiment is different from an ionic liquid consisting of cationic species and anionic species, and consists of a hydrogen bond acceptor and a hydrogen bond donor, and by mixing these two components, A eutectic melting point depression occurs.
The deep eutectic solvent may be liquid or solid at room temperature (25°C), but from the perspective of handling as a lubricant, one that is liquid at room temperature (25°C) is preferable. preferable.

When the lubricant of this embodiment uses a deep eutectic solvent as a base, it preferably contains 50% by mass or more, and preferably 70% by mass or more of the deep eutectic solvent based on the total amount of the lubricant. More preferably, the content is more preferably 90% by mass or more.
On the other hand, when the deep eutectic solvent is used as an additive, the deep eutectic solvent may be contained in an amount of about 0.1 to 10% by mass based on the total amount of the lubricant.

<Hydrogen bond acceptor>
The hydrogen bond acceptor contained in the lubricant of this embodiment may be any hydrogen bond acceptor as long as it forms a eutectic with the hydrogen bond donor. However, as mentioned above, since the content of halogen atoms in the lubricant of this embodiment needs to be 0.1% by mass or less, the hydrogen bond acceptor must not contain halogen atoms. A preferred example thereof is betaine.

More specifically, the betaine represented by the following general formula (1) is preferable.

(In the formula, R ¹ to R ³ are each independently a hydrocarbon group having 1 to 5 carbon atoms, and n is an integer of 1 to 3.)
The above R ¹ to R ³ are each independently preferably an alkyl group having 1 to 3 carbon atoms, more preferably an alkyl group having 1 or 2 carbon atoms.
The above n is preferably 1 or 2.
A specific example of betaine represented by the above general formula (1) is N,N,N-trimethylglycine.
As the hydrogen bond acceptor, one type of the above-described ones may be used alone, or two or more types may be used in combination.

<Hydrogen bond donor>
The hydrogen bond donor contained in the lubricant of this embodiment may be any hydrogen bond donor that forms a eutectic with the hydrogen bond acceptor. However, as mentioned above, since the content of halogen atoms in the lubricant of this embodiment needs to be 0.1% by mass or less, the hydrogen bond donor must not contain halogen atoms. Preferably, more specifically, one or more selected from alcohols, carboxylic acids, and nitrogen-containing compounds.

The alcohol preferably has 1 to 20 carbon atoms, more preferably 2 to 6 carbon atoms.
Specific examples of the alcohol include ethylene glycol, triethylene glycol, glycerin, pentaerythritol, dipentaerythritol, hexanediol, 1,4-butanediol, glucose, sucrose, xylose, mannitol, sorbitol, xylitol, D-sorbitol, Examples include polyhydric alcohols such as fructose, and aromatic alcohols such as phenol, cresol, resorcinol, hydroquinone, and phloroglucinol.

The above carboxylic acid preferably has 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and even more preferably 2 to 6 carbon atoms.
Specific examples of the above carboxylic acids include formic acid, acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, dodecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, and heptadecanic acid. fatty acids such as octadecanoic acid, eicosanoic acid, docosanoic acid, tetracosanoic acid, hexacosanoic acid, octacosanoic acid, triacontanic acid; hydroxy acids such as lactic acid, tartaric acid, malic acid, ascorbic acid, citric acid; adipic acid, malonic acid , dicarboxylic acids such as oxalic acid, succinic acid, suberic acid, itaconic acid; tricarboxylic acids such as 1,2,3-propanetricarboxylic acid; benzoic acid, phenylacetic acid, 3-phenylpropionic acid, 4-hydroxybenzoic acid, coffee Examples include aromatic carboxylic acids such as p-coumaric acid, trans-cinnamic acid, and gallic acid; keto acids such as levulinic acid.

The nitrogen-containing compound preferably has 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, and even more preferably 1 to 6 carbon atoms.
Specific examples of the nitrogen-containing compounds include urea, thiourea, 1-methylurea, 1,3-dimethylurea, 1,1-dimethylurea, acetamide, benzamide, imidazole, benzimidazole, and the like.
As the hydrogen bond donor, one type of the above-described ones may be used alone, or two or more types may be used in combination.

Preferably, in the lubricant of the present embodiment, the content of the hydrogen bond acceptor is 25 to 75% by mass based on the total amount of the lubricant, and the content of the hydrogen bond donor is 25 to 75% by mass based on the total amount of the lubricant. 75% by mass, more preferably, the content of the hydrogen bond acceptor is 35 to 65% by mass based on the total amount of lubricant, and the content of the hydrogen bond donor is 35% by mass based on the total amount of lubricant. ~65% by mass, more preferably, the content of the hydrogen bond acceptor is 40 to 60% by mass based on the total amount of lubricant, and the content of the hydrogen bond donor is 40% by mass based on the total amount of lubricant. ~60% by mass.

Further, the molar ratio between the content of the hydrogen bond acceptor and the content of the hydrogen bond donor in the lubricant of the present embodiment is 0.1 to 20 mol of the hydrogen bond donor to 1 mol of the hydrogen bond acceptor. The amount is preferably from 0.2 to 5.0 mol, even more preferably from 0.5 to 4.0 mol, and particularly preferably from 0.8 to 3.0 mol.

<Mineral oil and synthetic oil>
The lubricant of this embodiment is preferably composed only of the deep eutectic solvent from the viewpoint of carbon neutrality, but it may also contain one or more selected from mineral oil and synthetic oil. , mineral oil and synthetic oil. Even when lubricating oils contain one or more selected from mineral oils and synthetic oils, the amount of mineral oils and synthetic oils used can be reduced in proportion to the amount of deep eutectic solvent blended compared to conventional lubricating oils. Therefore, it can contribute to achieving carbon neutrality.
Therefore, from the viewpoint of carbon neutrality, the total content of mineral oil and/or synthetic oil in the lubricant of this embodiment is preferably 0 to 50% by mass, and 0 to 50% by mass, based on the total amount of the lubricant. It is more preferably 30% by mass, and even more preferably from 0 to 10% by mass.

Mineral oils include, for example, atmospheric residual oils obtained by atmospheric distillation of crude oils such as paraffinic crude oils, intermediate base crude oils, and naphthenic crude oils; and distillate oils obtained by vacuum distillation of these atmospheric residual oils. Examples include mineral oils obtained by subjecting the distillate to one or more refining treatments such as solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, and hydrorefining.

Examples of synthetic oils include polyα-olefins such as α-olefin homopolymers and α-olefin copolymers (for example, α-olefin copolymers having 8 to 14 carbon atoms such as ethylene-α-olefin copolymers). -Olefin; Isoparaffin; Various esters such as polyol esters and dibasic acid esters; Various ethers such as polyphenyl ether; Polyalkylene glycol; Alkylbenzene; Alkylnaphthalene; Wax produced from natural gas by the Fischer-Tropsch process etc. Examples include GTL base oil obtained by isomerizing (GasToLiquidsWAX)).

There are no particular limitations on the kinematic viscosity and viscosity index of the lubricant of this embodiment, but for example, the kinematic viscosity at 100°C is preferably 1.0 mm ² /s or more, more preferably 2.0 mm ^{2 /} s. s or more, more preferably 2.5 mm ² /s or more, preferably 50.0 mm ² /s or less, more preferably 30.0 mm ² /s or less, still more preferably 20. It is 0 mm ² /s or less. Further, these upper limit values and lower limit values can be arbitrarily combined, and specifically, preferably 1.0 to 50.0 mm ² /s, more preferably 2.0 to 30.0 mm ² /s, More preferably, it is 2.5 to 20.0 mm ² /s.
The viscosity index of the lubricant is preferably 80 or more, more preferably 90 or more, and still more preferably 100 or more.
Note that in this specification, kinematic viscosity and viscosity index mean values measured or calculated in accordance with JIS K 2283:2000.

The lubricant of this embodiment may further contain a lubricant additive in addition to the deep eutectic solvent.
As the lubricant additives, those conventionally used as lubricant additives can be selected, such as antioxidants, detergent dispersants, extreme pressure agents, oiliness agents, pour point depressants, and viscosity index. One or more selected from the group consisting of improvers, rust preventives, copper deactivators, and antifoaming agents may be mentioned.
In addition, in this specification, additives such as pour point depressants, viscosity index improvers, and antifoaming agents are used in consideration of handling properties and solubility in lubricants, and additives such as pour point depressants, viscosity index improvers, and antifoaming agents are used in the above lubricants or other base oils, etc. It may be in the form of a solution that is diluted and dissolved in a portion of diluted oil.

When the lubricant of the present embodiment contains a lubricant additive, the content of the deep eutectic solvent is not particularly limited, but is preferably 60 to 99% based on the total amount (100% by mass) of the lubricant. % by weight, more preferably 70-98% by weight, even more preferably 80-97% by weight, particularly preferably 85-95% by weight.

Furthermore, the lubricant of this embodiment may be in the form of a grease composition that further contains a thickener in addition to the above lubricant additives.

[Lubrication method]
The lubrication method of this embodiment uses the lubricant, and more specifically, is a method of lubricating metal members with the lubricant interposed therebetween.

[Lubricant manufacturing method]
The method for producing a lubricant of this embodiment includes a step of mixing a hydrogen bond acceptor and a hydrogen bond donor to obtain a deep eutectic solvent.
Details of the hydrogen bond acceptor and hydrogen bond donor are the same as described above.

The lubricant manufacturing method of the present embodiment includes the step of obtaining a deep eutectic solvent in the above lubricant manufacturing method, and the step of mixing a lubricant additive at at least one of the timings after the step. It is something that you have.
Details of the lubricant additive are the same as those described above.

[Uses of lubricant]
Applications of the lubricant of this embodiment include, for example, internal combustion engines, drive systems, hydraulic oil, automatic transmission oil, manual transmission oil, shock absorber oil, gear oil, fluid bearing oil, rolling bearing oil, and oil-impregnated bearing oil. Examples include oil, sliding surface oil, refrigeration machine oil, cutting oil, metal working oil such as plastic working oil, heat treatment oil, heat transfer oil, and the like.

Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to these examples in any way. In addition, various properties of each component and the obtained lubricant used in Examples and Comparative Examples were measured by the following methods.

<Kinematic viscosity, viscosity index>
Measured or calculated in accordance with JIS K 2283:2000.

Example 1
11.7 g of solid N,N,N-trimethylglycine, which is a hydrogen bond acceptor, and 18.4 g of viscous liquid glycerin, which is a hydrogen bond donor, were placed in a beaker equipped with a stirring bar and stirred at 80° C. for 1 hour. However, the entire mixture became a homogeneous and transparent liquid.
The kinematic viscosity and viscosity index at 40° C. of the obtained lubricant were measured, and a reciprocating friction test was conducted under the conditions shown below to measure the coefficient of kinetic friction at the 30th sliding reciprocation.

[Reciprocating friction test]
・Ball material: SUJ2 1/2 inch ・Sliding material: Stainless steel (SUS304), steel plate (SPCC-SD)
・Test temperature: 30℃
・Sliding number: 30 reciprocations ・Sliding speed: 5mm/s
・Stroke width: 20mm
・Load: 1.0kgf

Example 2
11.7 g of solid N,N,N-trimethylglycine, which is a hydrogen bond acceptor, and 13.4 g of solid malic acid, which is a hydrogen bond donor, were placed in a beaker equipped with a stirring bar and stirred at 80°C for 1 hour. As a result, the entire mixture became a homogeneous and transparent liquid.
The obtained lubricant was measured for its kinematic viscosity and viscosity index at 40°C, and also subjected to a reciprocating friction test to measure the coefficient of kinetic friction at the 30th sliding reciprocation.

Comparative example 1
The kinematic viscosity and viscosity index at 40°C were measured for mineral oil with a neutral fraction of 500, and a reciprocating friction test was conducted to measure the coefficient of kinetic friction at the 30th sliding reciprocation.

Comparative example 2
A lubricant was prepared in the same manner as in Example 1, except that 27.8 g of tetrabutylammonium chloride (TBAC) was used as the hydrogen bond acceptor and 20.0 g of dodecanoic acid was used as the hydrogen bond donor.
Regarding the obtained lubricant, the 40° C. kinematic viscosity and viscosity index were measured, and a reciprocating friction test was conducted to measure the kinetic friction coefficient at the 30th sliding reciprocation.

Comparative example 3
A lubricant was prepared in the same manner as in Example 1, except that 13.9 g of choline chloride was used as the hydrogen bond acceptor and 13.4 g of glycerin was used as the hydrogen bond donor.
The obtained lubricant was measured for its kinematic viscosity and viscosity index at 40°C, and also subjected to a reciprocating friction test to measure the coefficient of kinetic friction at the 30th sliding reciprocation.

It was confirmed that the lubricants prepared in Examples 1 and 2 had low friction coefficients in the reciprocating friction test and had excellent lubricity.

Claims

A lubricant containing a deep eutectic solvent consisting of a hydrogen bond acceptor and a hydrogen bond donor, and having a halogen atom content of 0.1% by mass or less.
The lubricant according to claim 1, wherein the hydrogen bond acceptor is betaine.
The lubricant according to claim 2, wherein the betaine is represented by the following general formula (1).

(In the formula, R 1 to R 3 are each independently a hydrocarbon group having 1 to 5 carbon atoms, and n is an integer of 1 to 3.)
The lubricant according to any one of claims 1 to 3, wherein the hydrogen bond donor is one or more selected from alcohols, carboxylic acids, and nitrogen-containing compounds.
The lubricant according to any one of claims 1 to 4, wherein the hydrogen bond donor is glycerin or malic acid.
The lubricant according to any one of claims 1 to 5, further comprising one or more selected from the group consisting of mineral oil and synthetic oil.
The lubricant according to any one of claims 1 to 6, which contains the deep eutectic solvent in an amount of 50% by mass or more based on the total amount of the lubricant.
Any one of claims 1 to 7, wherein the content of the hydrogen bond acceptor is 25 to 75% by mass based on the total amount of the lubricant, and the content of the hydrogen bond donor is 25 to 75% by mass based on the total amount of the lubricant. The lubricant according to item 1.
The lubricant according to any one of claims 1 to 8, further comprising a lubricant additive.
A lubrication method using the lubricant according to any one of claims 1 to 9.
The method for producing a lubricant according to any one of claims 1 to 9, comprising the step of mixing a hydrogen bond acceptor and a hydrogen bond donor to obtain a deep eutectic solvent.
The method for producing a lubricant according to claim 11, further comprising the step of obtaining the deep eutectic solvent and the step of further mixing a lubricant additive at at least one of the timings after the step.