JP2012136649A - Grease composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grease composition which has long life, excellent low volatility and non-combustibility even in use under high-temperature environment, and hardly corrodes metal at high temperature.SOLUTION: The grease composition includes a base oil and a thickener. The base oil is an ion liquid represented by general formula (1): ZA, (Zmeans a cation, and Ameans an anion), wherein Zis a cyclic quaternary ammonium ion having two different side chains, and Ais a conjugate amide ion.

Description

  The present invention relates to a grease composition.

With the advancement of machines and the increased awareness of maintenance-free operation, the usage conditions for lubrication with grease have become increasingly severe. In particular, a grease composition that is stable for a long period of time in a high-temperature environment is directly related to extending the life of the machine, and thus its performance has been required to be improved.
Further, in electronic device parts and manufacturing facilities that have made remarkable progress in recent years, low evaporative grease has been demanded because contamination due to grease decomposition products becomes a problem.
Under these circumstances, greases based on perfluoroalkyl polyether (hereinafter referred to as “PFAE”) have been proposed as long-lived greases even in high-temperature environments, but fluorinated oils decompose under high-temperature friction environments. Therefore, the use conditions are limited. Therefore, currently, the grease replenishment cycle is shortened or the replacement cycle of the parts is shortened.

On the other hand, in recent years, it has been reported that an ionic liquid composed of a cation and an anion has excellent thermal stability and low evaporation property, and becomes a stable liquid even in air (for example, see Non-Patent Document 1). . And various applications, such as electrolytes for solar cells, extraction, etc., taking advantage of its features such as thermal stability (hardly volatile, flame retardant), high ion density (high ionic conductivity), large heat capacity, and low viscosity Application research is actively conducted as a separation solvent, a reaction solvent, a lubricating oil (see, for example, Patent Document 1), and the like.
And the grease composition which used such ionic liquid as base oil is proposed (for example, refer patent document 2). Since ionic liquids are not linked by intermolecular attractive forces like molecular liquids but by strong ionic bonds, ionic liquids are difficult to volatilize and are flame retardant, and are resistant to heat and oxidation. It is a stable liquid. Therefore, grease compositions based on ionic liquids have long life even when used in high temperature environments, have excellent low evaporation properties, and are nonflammable. It can exhibit excellent lubricity and can meet the demand for maintenance-free.

International Publication No. 2005/035702 JP 2006-291011 A

“J. Chem. Soc., Chem. Commun.”, 1992, p. 965

  However, the ionic liquid described in the example of Patent Document 2 is not sufficient in that it easily corrodes a metal in a high temperature environment. Moreover, in patent document 2, it is not clear about what kind of ionic liquid is optimally selected as an ionic liquid used for a grease composition.

  Therefore, the present invention has been made in view of the above circumstances, and has a long life even when used in a high temperature environment, has excellent low evaporation properties, is nonflammable, and does not corrode metals at high temperatures. An object is to provide a composition.

  As a result of intensive studies to solve the above problems, the present inventor has found that the above object can be achieved by using an ionic liquid comprising a specific anion and cation as a base oil in a grease composition. It was. The present invention has been completed based on such findings.

That is, the grease composition of the present invention (hereinafter also referred to as “the present composition”) is a grease composition containing a base oil and a thickener, and the base oil has the following general formula (1):
Z ⁺ A ⁻ (1)
(Z ⁺ means a cation, and A ⁻ represents an anion.)
Wherein Z ⁺ is a cyclic quaternary ammonium ion having two different side chains, and A ⁻ is a conjugated amide ion.

In the grease composition of the present invention, the thickener is preferably at least one selected from the group consisting of a urea compound, bentonite, and polytetrafluoroethylene (hereinafter referred to as PTFE).
The grease composition of the present invention preferably has a dropping point of 230 ° C. or higher.

In the grease composition of the present invention, A ⁻ in the ionic liquid represented by the general formula (1) is the following general formula (2):

(In general formula (2), n is an integer from 1 to 4, m is an integer from 1 to 4, and they may be the same or different.)
It is preferable that it is chosen from the anions which have a structure represented by these.

In the grease composition of the present invention, Z ⁺ in the ionic liquid represented by the general formula (1) is the following general formula (3):

(In General Formula (3), n is 1 or 2, X is methylene or oxygen, and R ¹ and R ² are carbon atoms that may have an ether group, an ester group, a nitrile group, or a silyl group. It is a group selected from 1 to 12 alkyl groups.)
It is preferable that it is chosen from the cations which have a structure represented by these.

In the grease composition of the present invention, the molecular weight of the ionic liquid is preferably 410 or more and 570 or less.
In the grease composition of the present invention, it is preferable that the ionic liquid has a 40 ° C. kinematic viscosity of 1 mm ² / s to 100 mm ² / s.

In the grease composition of the present invention, the pour point of the ionic liquid is preferably 0 ° C. or lower.
In the grease composition of the present invention, the thickener is preferably contained in an amount of 3% by mass to 50% by mass with respect to the total amount of the grease composition.
The grease composition of the present invention is preferably used for lubrication of vacuum equipment or semiconductor manufacturing equipment.

  According to the present invention, it is possible to provide a grease composition that has a long life even when used in a high temperature environment, has an excellent low evaporation property, is nonflammable, and hardly corrodes metals at high temperatures.

The grease composition of the present invention comprises a base oil and a thickener.
Base oil has the general formula:
Z ⁺ A ⁻ (4)
(Z ⁺ means a cation and A ⁻ means an anion.)
Wherein Z ⁺ is a cyclic quaternary ammonium ion having two different side chains, and A ⁻ is a conjugated amide ion.
In the case of cyclic quaternary ammonium ions having the same side chain, the quaternary ammonium ion becomes solid at room temperature and the lubricity as a grease is impaired, so that it cannot be used in a wide temperature range.

A ⁻ in the general formula (4) is preferably selected from conjugated amide ions having a structure represented by the following general formula (5).

  In the general formula (5), n is an integer from 1 to 4, and is preferably 1 or 2 from the viewpoint of the molecular weight of the ionic liquid. M is an integer from 1 to 4, and is preferably 1 or 2 from the viewpoint of the molecular weight of the ionic liquid. m and n may be the same or different.

  Examples of the conjugated amide ion having the structure represented by the general formula (5) include bis (trifluoromethanesulfonyl) amide, bis (pentafluoroethanesulfonyl) amide, bis (heptafluoropropanesulfonyl) amide, and bis (nona). Fluorobutanesulfonyl) amide, trifluoromethanesulfonyl (pentafluoroethanesulfonyl) amide, pentafluoroethanesulfonyl (heptafluoropropanesulfonyl) amide, heptafluoropropanesulfonyl (nonafluorobutanesulfonyl) amide, trifluoromethanesulfonyl (heptafluoropropanesulfonyl) Amides, pentafluoroethanesulfonyl (nonafluorobutanesulfonyl) amide, and trifluoromethanesulfonyl (nonafluorobutane) Ruhoniru) amide.

  Among these, bis (trifluoromethanesulfonyl) amide, bis (pentafluoroethanesulfonyl) amide, and trifluoromethanesulfonyl (pentafluoroethanesulfonyl) amide are preferable from the viewpoint of setting the molecular weight of the ionic liquid within a specific range described later. Bis (trifluoromethanesulfonyl) amide is particularly preferred.

As anions other than the general formula (5), Cl ⁻ , Br ⁻ , I ⁻ , RSO ₃ ⁻ , R0SO ₃ ⁻ , RCO ₂ ⁻ , NO ₃ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , SCN ⁻ , N (CN) _{^{2 -, C (CN) 3}} -, PF 3 (C 2 F 5) 3 -, B (C 2 O 4) 2 - molecules, but such is known, which is highly conjugated ^-, B _{(CN) 4} Since it is not a structure, it has a drawback of being inferior in thermal stability as compared with the general formula (5).

On the other hand, Z ⁺ is preferably selected from cations (cyclic quaternary ammonium ions) having a structure represented by the following general formula (6).

In the general formula (6), n is 1 or 2, and X is methylene or oxygen. R ¹ and R ² are groups selected from an alkyl group having 1 to 12 carbon atoms which may have an ether group (ether bond), an ester group (ester bond), a nitrile group, or a silyl group. The number of carbon atoms of such an alkyl group is more preferably from 1 to 6, more preferably from 1 to 4, from the viewpoint of reducing the viscosity of the ionic liquid and improving the heat resistance (high-temperature oxidation stability). Particularly preferred.

  Examples of the cyclic quaternary ammonium ion having the structure represented by the general formula (6) include 1-butyl-1-methylpyrrolidinium, 1-pentyl-1methylpyrrolidinium, 1-hexyl-1-methylpyrrole. Dinium, 1-heptyl-1 methylpyrrolidinium, 1-octyl-1 methylpyrrolidinium, 1-nonyl-1 methylpyrrolidinium, 1-decyl-1 methylpyrrolidinium, 1-undecyl-1 methylpyrrole Dinium, 1-dodecyl-1 methylpyrrolidinium, 1- (2-methoxyethyl) -1-methylpyrrolidinium, 1- (2-methoxy-2-oxoethyl) -1-methylpyrrolidinium, 1- Cyanomethyl-1-methylpyrrolidinium, 1-trimethylsilylmethyl-1-methylpyrrolidinium, 1-butyl-1-methylpiperidinium, 1-pentyl-1-methylpiperidinium, 1-hexyl-1-methylpiperidinium, 1-heptyl-1-methylpiperidinium, 1-octyl-1-methylpiperidinium, 1-nonyl-1- Methylpiperidinium, 1-decyl-1-methylpiperidinium, 1-undecyl-1-methylpiperidinium, 1-dodecyl-1-methylpiperidinium, 1- (2-methoxyethyl) -1-methyl Piperidinium, 1- (2-methoxy-2-oxoethyl) -1-methylpiperidinium, 1-cyanomethyl-1-methylpiperidinium, 1-trimethylsilylmethyl-1-methylpiperidinium, 1-butyl- 1-methylmorpholinium, 1-pentyl-1-methylmorpholinium, 1-hexyl-1-methylmorpholinium, 1-heptyl-1- Methylmorpholinium, 1-octyl-1-methylmorpholinium, 1-nonyl-1-methylmorpholinium, 1-decyl-1-methylmorpholinium, 1-undecyl-1-methylmorpholinium, 1 -Dodecyl-1-methylmorpholinium, 1- (2-methoxyethyl) -1-methylmorpholinium, 1- (2-methoxy-2-oxoethyl) -1-methylmorpholinium, 1-cyanomethyl-1 -Methylmorpholinium, 1-trimethylsilylmethyl-1-methylmorpholinium and the like.

  Among these, 1-butyl-1-methylpyrrolidinium, 1-pentyl-1methylpyrrolidinium, 1-hexyl- from the viewpoint of lowering the viscosity of the ionic liquid and improving heat resistance (high-temperature oxidation stability). 1-methylpyrrolidinium, 1- (2-methoxyethyl) -1-methylpyrrolidinium, 1-butyl-1-methylpiperidinium, 1- (2-methoxyethyl) -1-methylpiperidinium, 1- (2-methoxyethyl) -1-methylmorpholinium is preferred, 1-butyl-1-methylpyrrolidinium, 1- (2-methoxyethyl) -1-methylpyrrolidinium, and 1- (2 -Methoxyethyl) -1-methylpiperidinium is particularly preferred.

  As cations other than the general formula (6), imidazolium, pyridinium, guanidinium, aliphatic quaternary ammonium, aliphatic quaternary phosphonium, aliphatic sulfonium and the like are known. However, since the Lewis acidity is high, the general formula ( Compared with 6), it has a drawback of high-temperature metal corrosivity.

The molecular weight of the ionic liquid is preferably 410 or more and 570 or less, more preferably 410 or more and 470 or less, and particularly preferably 420 or more and 440 or less. When the molecular weight is within the above range, the charge density and the alkyl chain of the cation are in an appropriate range, and the viscosity of the ionic liquid can be reduced and the heat resistance (high-temperature oxidation stability) can be improved.
The kinematic viscosity at 40 ° C. of the ionic liquid is preferably 1 mm ² / s to 100 mm ² / s, preferably 10 mm ² / s to 70 mm ² from the viewpoint of suppressing evaporation loss and power loss due to viscous resistance. / S or less is more preferable, and 20 mm ² / s or more and 40 mm ² / s or less is particularly preferable.
Furthermore, the pour point of the ionic liquid is preferably 0 ° C. or less, more preferably −10 ° C. or less, and preferably −20 ° C. or less from the viewpoint of suppressing increase in viscous resistance at low temperatures. Particularly preferred.

The acid value of the ionic liquid is preferably 1 mgKOH / g or less, more preferably 0.5 mgKOH / g or less, and 0.3 mgKOH / g or less from the viewpoint of preventing corrosion of metals and the like. Particularly preferred.
The flash point of the ionic liquid is preferably 200 ° C. or higher, more preferably 250 ° C. or higher, and particularly preferably 300 ° C. or higher, from the viewpoint of reducing the evaporation amount of the base oil.
The viscosity index of the ionic liquid is preferably 80 or more, more preferably 100 or more, and particularly preferably 120 or more from the viewpoint of preventing the viscosity change with respect to temperature from becoming too large.

In the ionic liquid preferably has ion concentration measured at 20 ° C. is 1 mol / dm ³ or more, more preferably 1.5 mol / dm ³ or more, particularly preferably 2 mol / dm ³ or more. Here, the ion concentration is a value calculated by [density (g / cm ³ ) / molecular weight Mw (g / mol)] × 1000 in the ionic liquid. When the ion concentration of the ionic liquid is less than 1 mol / dm ³ , the low evaporation property and heat resistance, which are the characteristics of the ionic liquid, are lowered, which is not preferable.

The dropping point of the grease composition of the present invention is preferably 230 ° C. or higher, more preferably 260 ° C. or higher, and particularly preferably 300 ° C. or higher.
Examples of the thickener used for obtaining the dropping point include at least one selected from the group consisting of a urea compound, bentonite, and PTFE. Lithium soap, calcium soap, and the like make it difficult to grease the ionic liquid represented by the general formula (4), and even if it can be made, the dropping point of the grease composition is 230 ° C. or less, and the heat resistance is insufficient. . In the case of a silica compound, the friction and wear of the grease composition increases, and in some cases, seizure may occur and lubrication becomes impossible.

  Furthermore, in the grease composition of the present invention, the thickener is preferably 3% by mass or more and 50% by mass or less with respect to the total amount of the grease composition. If the amount of the thickener is too small, it may be too soft and not greased, and if it is too much, it may become hard and cause poor lubrication. From the balance of hardness and softness, it is more preferably 5% by mass or more and 45% by mass or less, and particularly preferably 10% by mass or more and 40% by mass or less.

The grease composition of the present invention can be used in various applications as a grease composition by blending predetermined additives. Examples of the additive include an antioxidant, an oily agent, an extreme pressure agent, a cleaning dispersant, a viscosity index improver, a rust inhibitor, a metal deactivator, and an antifoaming agent. These can be used alone or in combination of two or more. Depending on the application, the grease composition may be used as it is without adding an additive.
As the antioxidant, amine-based antioxidants, phenol-based antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants used in conventional grease compositions can be used. These antioxidants can be used alone or in combination of two or more. Examples of the amine antioxidant include monoalkyl diphenylamine compounds such as monooctyl diphenylamine and monononyl diphenylamine, 4,4′-dibutyldiphenylamine, 4,4′-dipentyldiphenylamine, 4,4′-dihexyldiphenylamine, Dialkyldiphenylamine compounds such as 4,4′-diheptyldiphenylamine, 4,4′-dioctyldiphenylamine, 4,4′-dinonyldiphenylamine, polybutyldiphenylamine, tetrahexyldiphenylamine, tetraoctyldiphenylamine, tetranonyldiphenylamine, etc. Alkyldiphenylamine compounds, α-naphthylamine, phenyl-α-naphthylamine, butylphenyl-α-naphthylamine, pentylphenyl-α- Fuchiruamin, hexylphenyl -α- naphthylamine, heptylphenyl -α- naphthylamine, octylphenyl -α- naphthylamine, and naphthylamine-based compounds such as nonylphenyl -α- naphthylamine.

Examples of the phenolic antioxidant include monophenolic compounds such as 2,6-di-tert-butyl-4-methylphenol and 2,6-di-tert-butyl-4-ethylphenol, 4,4 ′ Examples include diphenolic compounds such as -methylenebis (2,6-di-tert-butylphenol) and 2,2'-methylenebis (4-ethyl-6-tert-butylphenol).
Examples of the sulfur-based antioxidant include 2,6-di-tert-butyl-4- (4,6-bis (octylthio) -1,3,5-triazin-2-ylamino) phenol, phosphorus pentasulfide and Examples thereof include thioterpene compounds such as a reaction product with pinene, and dialkylthiodipropionates such as dilauryl thiodipropionate and distearyl thiodipropionate.
Examples of phosphorus antioxidants include triphenyl phosphite, diethyl [3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] phosphonate, and the like.
The blending amount of these antioxidants is usually about 0.01% by mass or more and 10% by mass or less, and preferably 0.03% by mass or more and 5% by mass or less, based on the total amount of the grease composition.

  Examples of the oily agent include fatty alcohols, fatty acid compounds such as fatty acids and fatty acid metal salts, ester compounds such as polyol esters, sorbitan esters, and glycerides, and amine compounds such as aliphatic amines. The blending amount of these oiliness agents is usually 0.1% by mass or more and 30% by mass or less, and preferably 0.5% by mass or more and 10% by mass or less, based on the total amount of the grease composition, from the viewpoint of the blending effect. .

Examples of the extreme pressure agent include a sulfur-based extreme pressure agent, a phosphorus-based extreme pressure agent, an extreme pressure agent containing sulfur and a metal, and an extreme pressure agent containing phosphorus and a metal. These extreme pressure agents can be used alone or in combination of two or more. Any extreme pressure agent may be used as long as it contains at least one of a sulfur atom and a phosphorus atom in the molecule and can exhibit load resistance and wear resistance. Examples of extreme pressure agents containing sulfur in the molecule include sulfurized fats and oils, sulfurized fatty acids, sulfurized esters, sulfurized olefins, dihydrocarbyl polysulfides, thiadiazole compounds, alkylthiocarbamoyl compounds, triazine compounds, thioterpene compounds, dialkylthiodipropionate compounds, etc. Can be mentioned.
As extreme pressure agents containing sulfur, phosphorus and metals, zinc dialkylthiocarbamate (Zn-DTC), molybdenum dialkylthiocarbamate (Mo-DTC), lead dialkylthiocarbamate, tin dialkylthiocarbamate, dialkyldithiophosphate Examples include zinc (Zn-DTP), molybdenum dialkyldithiophosphate (Mo-DTP), sodium sulfonate, calcium sulfonate, and the like. Typical examples of extreme pressure agents containing phosphorus in the molecule are phosphate esters such as tricresyl phosphate and amine salts thereof. The blending amount of these extreme pressure agents is usually 0.01% by mass or more and 30% by mass or less, more preferably 0.01% by mass or more and 10% by mass or more based on the total amount of the grease composition from the viewpoint of blending effect and economy. % Or less.

Examples of the cleaning dispersant include metal sulfonate, metal salicylate, metal finate, and succinimide. The blending amount of these detergent dispersants is usually 0.1% by mass or more and 30% by mass or less, and preferably 0.5% by mass or more and 10% by mass or less based on the total amount of the composition from the viewpoint of the blending effect.
Examples of the viscosity index improver include polymethacrylate, dispersed polymethacrylate, olefin copolymer (for example, ethylene-propylene copolymer), dispersed olefin copolymer, styrene copolymer (for example, Styrene-diene hydrogenated copolymer, etc.). The blending amount of these viscosity index improvers is usually 0.5% by mass or more and 35% by mass or less, and preferably 1% by mass or more and 15% by mass or less based on the total amount of the lubricating oil from the viewpoint of the blending effect.
Examples of the rust inhibitor include metal sulfonates, alkyl succinates, sorbitan monoesters, metal carboxylates, alkanolamines such as alkylamines and monoisopropanolamine. The blending amount of these rust preventives is usually 0.01% by mass or more and 10% by mass or less, preferably 0.05% by mass or more and 5% by mass or less, based on the total amount of the grease composition, from the viewpoint of the blending effect. .
Examples of the metal deactivator include benzotriazole and thiadiazole. The preferred compounding amount of these metal deactivators is usually 0.01% by mass or more and 10% by mass or less, preferably 0.01% by mass or more and 1% by mass or less, based on the total amount of the lubricating oil, from the viewpoint of the blending effect. It is.
Examples of the antifoaming agent include methyl silicone oil, fluorosilicone oil, and polyacrylate. The blending amount of these antifoaming agents is usually 0.0005% by mass or more and 0.01% by mass or less based on the total amount of the grease composition from the viewpoint of blending effect.

In the grease composition of the present invention, as the base oil, in addition to the above ionic liquid, other base oils can be used in combination as long as the object of the present invention is not impaired. Other base oils can be appropriately selected from, for example, mineral oil and synthetic oil. Examples of mineral oils include distillate oils obtained by atmospheric distillation of paraffinic crude oil, intermediate crude oil or naphthenic crude oil, or by distilling atmospheric distillation residue oil under reduced pressure. Refined oils obtained by refining, specifically solvent refined oils, hydrogenated refined oils, dewaxed oils, clay-treated oils, and the like.
Synthetic oils include, for example, low molecular weight polybutene, low molecular weight polypropylene, α-olefin oligomers having 8 to 14 carbon atoms and hydrides thereof, polyol esters (eg, fatty acid ester of trimethylolpropane, fatty acid of pentaerythritol). Ester), dibasic acid ester, aromatic polycarboxylic acid ester (eg trimellitic acid ester, pyromellitic acid ester, etc.), ester compound such as phosphoric acid ester, alkyl aroma compound such as alkylbenzene and alkylnaphthalene, silicone Examples thereof include oils and fluorine-based oils (for example, fluorocarbon, perfluoropolyether, etc.).
These other base oils can be used singly or in combination of two or more.
However, in order to exert the effect as the grease composition of the present invention, the ratio of the ionic liquid in the base oil in the grease composition is preferably 50% by mass or more, and preferably 70% by mass or more. More preferably, it is still more preferably 90% by mass or more, and particularly preferably 100% by mass.

  In the grease composition of the present invention, the amount of moisture mixed is preferably 3000 ppm by mass or less, more preferably 500 ppm by mass or less, and particularly preferably from the viewpoint of preventing viscosity reduction and corrosion. Is 100 mass ppm or less.

The grease composition of the present invention has a long life even when used in a high temperature environment, exhibits low evaporability, is nonflammable, and is difficult to corrode metals at high temperatures, and thus can be applied to various fields.
For example, it is suitable for lubrication of vacuum equipment or semiconductor manufacturing equipment.

  The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Various characteristics of the base oil and the grease composition were measured according to the following methods.

Characteristic evaluation of base oil (1) Kinematic viscosity Measured according to "Petroleum product kinematic viscosity test method" defined in JIS K2283.
(2) Viscosity index It measured based on the "petroleum product kinematic viscosity test method" prescribed | regulated to JISK2283.
(3) Pour point Measured according to the method described in JIS K2269.
(4) 5% mass reduction temperature Using a differential thermal analyzer, the temperature was increased at a rate of 10 ° C./min, and the temperature reduced by 5 mass% from the initial mass was measured. It can be said that the higher the 5% mass loss temperature, the better the evaporation resistance and heat resistance.
(5) Friction characteristics (friction coefficient and wear width)
Using a ball-on-disk type reciprocating friction tester (Bauden-Leven type), the friction coefficient and the wear width were measured under the conditions of a load of 20 N, a temperature of 80 ° C., a sliding speed of 30 mm ² / s, and a stroke of 15 mm. The material of the ball is SUJ2, the diameter of the ball is 10 mm, and the material of the disk is SUJ2. It can be said that the smaller the friction coefficient and the wear width, the better the lubricity and wear resistance.
(6) Metal corrosivity In 8 mL of ionic liquid, iron-based (iron content is 99% by mass or more) and copper-based (copper content is 93% by mass to 98% by mass, tin content is 2% by mass to 7% by mass) Each of the other sintered bearings having a metal content of 1% by mass or less) was simultaneously immersed and allowed to stand at 140 ° C. for 240 hours, and then the appearance of the ionic liquid was observed. The bearing has an outer diameter of 12 mm and a thickness of 4 mm. And metal corrosivity was evaluated based on the criteria shown below.
○: No metal elution and no corrosion.
Δ: Slightly brown or black eluate is observed (slightly corroded).
X: There is a brownish brown or black eluate (corrosion).

Characterization of grease composition (1) Consistency number:
Conforms to the classification based on JIS K2220-2003 Table 1.
(2) Dropping point:
JIS K2220-2003 8. Measured in accordance with the test method specified in 1.
(3) Long-term stability at high temperature:
JIS K2220-2003 21. After the SPCC steel plate for (wetting test) was washed with a solvent, the grease composition was applied to a thickness of 2.0 mm, and the state of the grease after heating at 250 ° C. for 12 hours was evaluated.
○: Grease is maintained.
X: Solidified.
(4) 5% mass loss temperature:
Using a differential thermal analyzer, the temperature was increased at a rate of 10 ° C./min, and the temperature decreased by 5 mass% from the initial mass was measured. It shows that it is excellent in evaporation resistance and heat resistance, so that 5% mass loss temperature is high.
(5) High temperature metal corrosivity:
JIS K2220-2003 21. After the SPCC steel plate for (wetting test) was washed with a solvent, the grease composition was applied to a thickness of 1.0 mm, and the surface state of the SPCC steel plate after heating at 200 ° C. for 30 minutes was evaluated.
○: There is no corrosion.
X: The surface is changed to dark brown or black (corrosion occurs).

[Preparation of base oil and grease composition]
(1) Ionic liquid grease 1: Ionic liquid 1 (1-butyl-1-methylpyrrolidinium bis (trifluoromethanesulfonyl) amide) + PTFE
To a 1 L flask, 1-methylpyrrolidine (50 g, 0.585 mol) and 2-propanol 70 mL were added under a nitrogen atmosphere. 1-Bromobutane (96.5 g, 0.705 mol) was added dropwise thereto, and then the mixture was heated to 40 ° C. and reacted for 6 hours. After completion of the reaction, recrystallization was performed with acetic ether, and the crystals obtained by filtration were washed several times with acetic ether. Then, 1-butyl-1-methylpyrrolidinium bromide (halogen) was obtained by drying at 40 ° C. for several hours while reducing the pressure with a vacuum pump (113 g, 0.510 mol).
Next, the halogen body (113 g, 0.510 mol) and 110 mL of pure water were prepared in a 1 L flask, and an aqueous solution in which lithium bis (trifluoromethanesulfonyl) imide (151 g, 0.525 mol) was dissolved in 150 mL of pure water. Was dripped. The reaction mixture was stirred at room temperature for about 1 hour, transferred to a 1 L separatory funnel, extracted by adding 230 mL of methylene chloride, and the collected methylene chloride solution was washed several times with pure water. After washing, 1 to 2 mL of an aqueous layer was collected and reacted with about 1 mL of 0.5 M aqueous silver nitrate solution to confirm the presence or absence of precipitation (if white precipitate was observed, bromide ions were not completely removed. The washing was repeated until it disappeared.) After completion of water washing, the mixture was concentrated with a rotary evaporator, a small amount of activated carbon was added, and the mixture was stirred at room temperature for 1 day. The mixture was passed through a column of neutral alumina, and heated and stirred under reduced pressure (60 ° C., 4 hours) with a vacuum pump to obtain ionic liquid 1 (212 g, 0.50 mol).
Next, the ionic liquid 1 (204 g, 0.482 mol) was prepared in a 300 mL separable flask, and PTFE (Sumitomo 3M TF9207Z, 96 g) was slowly added under strong stirring. Furthermore, this reaction mixture was passed through a three-roll mill several times to obtain ionic liquid grease 1 (300 g).

(2) Ionic liquid grease 2: Ionic liquid 1 + bentonite Ionic liquid 1 (160 g, 0.378 mol) was prepared in a 300 mL separable flask, and bentonite (Toshin Kasei Benton 27, 40 g) was slowly added under strong stirring. . Furthermore, this reaction mixture was passed through a three-roll mill several times to obtain ionic liquid grease 2 (200 g).

(3) Ionic liquid grease 3: Ionic liquid 1 + Diurea Add ionic liquid 1 (156 g, 0.369 mol) and MDI (Cosmonate PH, 21.97 g, 0.088 mol) manufactured by Mitsui Chemicals to a 300 mL separable flask and stir. The temperature was raised to 80 ° C. After normal octylamine (22.03 g, 0.170 mol) was added dropwise, the temperature was further raised to 160 ° C. and held for 1 hour. After cooling, this reaction mixture was passed through a three-roll mill several times to obtain ionic liquid grease 2 (200 g).

(4) Ionic liquid grease 4: Ionic liquid 2 (1- (2-methoxyethyl) -1-methylpyrrolidinium bis (trifluoromethanesulfonyl) amide) + PTFE
In the synthesis of ionic liquid 1, instead of using 1-bromobutane, the same operation was performed except that 2-iodoethyl methyl ether (131 g, 0.705 mol) was used, and 1- (2-methoxyethyl) -1- Methylpyrrolidinium iodide (146 g, 0.538 mol) was obtained. Furthermore, in the synthesis of ionic liquid 1, 1- (2-methoxyethyl) -1-methylpyrrolidinium iodide (146 g, 0.538 mol) was used instead of 1-butyl-1-methylpyrrolidinium bromide. Ionic liquid 2 (212 g, 0.500 mol) was obtained in the same manner except that.
Subsequently, in the synthesis of the ionic liquid grease 1, the ionic liquid was operated in the same manner except that the ionic liquid 2 (131 g, 0.309 mol) was used instead of the ionic liquid 1 and PTFE (TF9207Z) (62 g) was used. Grease 4 (193 g) was obtained.

(5) Ionic liquid grease 5: Ionic liquid 3 (1- (2-methoxyethyl) -1-methylpiperidinium bis (trifluoromethanesulfonyl) amide) + PTFE
In the synthesis of ionic liquid 2, instead of using 1-methylpyrrolidine, 1-methylpiperidine (58 g, 0.585 mol) was used in the same manner as in 1- (2- Methoxyethyl) -1-methylpiperidinium iodide (161 g, 0.563 mol) was obtained. Further, in the synthesis of ionic liquid 2, instead of using 1- (2-methoxyethyl) -1-methylpyrrolidinium iodide, 1- (2-methoxyethyl) -1-methylpiperidinium iodide (161 g, 0 .Ionic liquid 3 (241 g, 0.549 mol) was obtained in the same manner except that .563 mol) was used.
Subsequently, in the synthesis of the ionic liquid grease 1, the ionic liquid was operated in the same manner except that the ionic liquid 3 (141 g, 0.322 mol) was used instead of the ionic liquid 1 and PTFE (TF9207Z) (59 g) was used. Grease 5 (200 g) was obtained.

(6) Ionic liquid grease 6: Ionic liquid 4 (1- (2-methoxyethyl) -1-methylmorpholinium bis (trifluoromethanesulfonyl) amide) + PTFE
In the synthesis of ionic liquid 3, instead of using 1-methylpiperidine, 1-methylmorpholine (59 g, 0.585 mol) was used in the same manner as in 1- (2- Methoxyethyl) -1-methylmorpholinium iodide (145 g, 0.505 mol) was obtained. Further, in the synthesis of ionic liquid 3, instead of using 1- (2-methoxyethyl) -1-methylpiperidinium iodide, 1- (2-methoxyethyl) -1-methylmorpholinium iodide (145 g, 0 The ionic liquid 4 (202 g, 0.460 mol) was obtained in the same manner except that.
Subsequently, in the synthesis of the ionic liquid grease 1, the ionic liquid was operated in the same manner except that the ionic liquid 4 (142 g, 0.322 mol) was used instead of the ionic liquid 1 and PTFE (TF9207Z) (58 g) was used. Grease 6 (200 g) was obtained.

(7) Ionic liquid grease 7: Ionic liquid 5 (1-butylpyridinium bis (trifluoromethanesulfonyl) amide) + PTFE
In the synthesis of ionic liquid 1, instead of using 1-methylpyrrolidine, pyridine (46 g, 0.585 mol) was used and the same procedure was followed except that isopropanol was changed to 200 mL of acetonitrile and reacted at 80 ° C. Butylpyridinium bromide (125 g, 0.579 mol) was obtained. Further, in the synthesis of the ionic liquid 1, the same operation was performed except that 1-butylpyridinium bromide (125 g, 0.579 mol) was used instead of 1-butyl-1-methylpyrrolidinium bromide. 234 g, 0.562 mol).
Subsequently, in the synthesis of the ionic liquid grease 1, the ionic liquid was operated in the same manner except that the ionic liquid 5 (137 g, 0.329 mol) was used instead of the ionic liquid 1 and PTFE (TF9207Z) (63 g) was used. Grease 7 (200 g) was obtained.

(8) Ionic liquid grease 8: Ionic liquid 6 (N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium bis (trifluoromethanesulfonyl) amide) + PTFE
Subsequently, in the synthesis of the ionic liquid grease 1, the ionic liquid was operated in the same manner except that the ionic liquid 6 (133 g, 0.312 mol) was used instead of the ionic liquid 1 and PTFE (TF9207Z) (67 g) was used. Grease 8 (200 g) was obtained.

(9) Ionic liquid grease 9: Ionic liquid 7 (1-butyl-3-methylimidazolium bis (trifluoromethanesulfonyl) amide) + PTFE
1-Methylimidazole (173 g, 2.100 mol) and 1-chlorobutane (234 g, 2.528 mol) were added to a 1 L flask under a nitrogen atmosphere and reacted at 90 ° C. for several hours. After completion of the reaction, recrystallization was performed with ether acetate and acetonitrile, and the crystals obtained by filtration were dried at 40 ° C. for several hours while reducing the pressure with a vacuum pump, whereby 1-butyl-1-methylimidazolium chloride (352 g) was obtained. 2.016 mol). An ionic liquid 7 (837 g, 1.996 mol) was obtained in the same manner as in the synthesis of the ionic liquid 1, except that this quaternary salt was used instead of 1-butyl-1-methylpyrrolidinium bromide.
Subsequently, in the synthesis of ionic liquid grease 1, the same operation was performed except that ionic liquid 7 (138.8 g, 0.331 mol) was used instead of ionic liquid 1, and PTFE (TF9207Z) (61.2 g) was used. Thus, ionic liquid grease 9 (200 g) was obtained.

[Examples 1-6, Comparative Examples 1-3]
The result measured about each characteristic of the obtained base oil and grease is shown to Tables 1-2.

  From the evaluation results shown in Tables 1 and 2, since the ionic liquids of Examples 1 to 6 hardly corrode metals at high temperatures and have good heat resistance, the grease composition has a long life even when used in a high temperature environment. Yes, it exhibits low evaporation, is nonflammable, and does not corrode metals at high temperatures. On the other hand, although the ionic liquids as in Comparative Examples 1 to 3 are excellent in heat resistance and lubricity, they are inferior in metal corrosion resistance at high temperatures, and are not suitable as grease compositions.

Claims (10)

A grease composition comprising a base oil and a thickener,
The base oil is
The following general formula (1):
Z ⁺ A ⁻ (1)
(Z ⁺ means a cation, and A ⁻ represents an anion.)
A grease composition comprising: an ionic liquid represented by the formula: wherein Z ⁺ is a cyclic quaternary ammonium ion having two different side chains, and A ⁻ is a conjugated amide ion. The grease composition according to claim 1,
The grease composition, wherein the thickener is at least one selected from the group consisting of a urea compound, bentonite, and polytetrafluoroethylene (PTFE). In the grease composition according to claim 1 or 2,
A grease composition having a dropping point of 230 ° C or higher. In the grease composition according to any one of claims 1 to 3,
A ⁻ in the ionic liquid represented by the general formula (1) is the following general formula (2):

(In general formula (2), n is an integer from 1 to 4, m is an integer from 1 to 4, and they may be the same or different.)
A grease composition characterized by being selected from anions having a structure represented by: In the grease composition according to any one of claims 1 to 4,
Z ⁺ in the ionic liquid represented by the general formula (1) is the following general formula (3):

(In the formula (3), n is 1 or 2, X is methylene or oxygen, and R ¹ and R ^{2 each} have an ether group, an ester group, a nitrile group, or a silyl group. To a group selected from alkyl groups of 1 to 12.)
A grease composition characterized by being selected from cations having a structure represented by: In the grease composition according to any one of claims 1 to 5,
A grease composition, wherein the molecular weight of the ionic liquid is 410 or more and 570 or less. In the grease composition according to any one of claims 1 to 6,
A grease composition, wherein the ionic liquid has a kinematic viscosity at 40 ° C. of 1 mm ² / s to 100 mm ² / s. In the grease composition according to any one of claims 1 to 7,
A grease composition having a pour point of the ionic liquid of 0 ° C. or lower. In the grease composition according to any one of claims 1 to 8,
3. The grease composition according to claim 1, wherein the thickener is contained in an amount of 3% by mass to 50% by mass with respect to the total amount of the grease composition. A grease composition, wherein the grease composition according to any one of claims 1 to 9 is used for lubrication of vacuum equipment or semiconductor manufacturing equipment.