JP2014065908A - Grease base oil and grease composition containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aromatic ester-based grease base oil having inexpensive price and deterioration (increase of oxidation) at high temperature as same as, or less than conventional polyol esters, and excellent in viscosity index and low temperature fluidity, and to provide a grease composition using the same.SOLUTION: A grease composition having preferable performance balance as a grease can be obtained by using a mixture of benzene dicarboxylic acid diester having a specific structure as grease oil excellent in oxidation stability and a viscosity index.

Description

The present invention relates to a grease base oil and a grease composition containing the same.

In recent years, equipment has become smaller, longer service life, and maintenance-free. As a result, lubricants such as grease are less likely to deteriorate even under harsh conditions (high temperature, high speed, high load), from low to high temperatures. There is a demand for good performance over a wide temperature range. Further, it is desired to reduce the torque by smoothly starting the mechanical device, that is, by reducing the viscosity of the base oil in the grease. In addition, from the perspective of environmental issues, factories, transportation companies, etc. are required to reduce power and fuel consumption more than ever. The grease used in various industrial machines and automobiles also has a power and fuel saving effect. Is required. As one of means for obtaining a power saving and fuel saving effect, it is effective to use a base oil having a low viscosity and a high viscosity index base oil. Mineral oil-based grease is generally used as grease, but demand for higher-performance synthetic oil-based grease is increasing. Ester-based, synthetic hydrocarbon-based, polyglycol-based, phenyl ether-based, silicone-based, fluorine-based synthetics Oil grease etc. are used according to the purpose.

Among the synthetic oils used in these grease base oils, ester compounds are generally superior in lubricity, temperature-viscosity characteristics (viscosity index), low-temperature fluidity, and heat resistance compared to mineral oil systems (Patent Document 1). .

Among them, aliphatic diester greases are particularly excellent in low temperature properties and are used as greases for low temperature or high speed rotary bearings (Patent Document 2). Polyol ester grease is excellent in thermal stability and oxidation stability at high temperatures, and also has good performance in a low temperature region, and is therefore preferably used as a long-life multipurpose grease (Patent Documents 3 and 4). ).

Recently, however, the use conditions are becoming more severe, and from the standpoint of extending the life of the grease and making it maintenance-free, there is an increasing demand for grease that is resistant to oxidative degradation. On the other hand, in the polyol ester grease currently used, the base oil deteriorates due to use at high temperature or continuous operation for a long time, and further, the base oil and the thickener are separated, and the grease properties change ( Patent Document 1). As a result, abnormal wear occurs in the lubricated portion, resulting in a problem of machine failure.

JP-A-10-88158 Japanese Patent Laid-Open No. 04-357318 Japanese Patent Laid-Open No. 04-236298 JP 2001-3070 A

The present invention is an aromatic ester-based grease base that is inexpensive and has little deterioration at a high temperature (an increase in acid value) as much as or more than that of a conventional polyol ester, and is excellent in viscosity index and low-temperature fluidity. An object is to provide an oil and a grease composition using the oil.

In general, aromatic esters are considered to be relatively unsuitable as grease base oils because they have a high pour point and a low viscosity index, and are not currently used as grease base oils. However, since the aromatic ester is relatively inexpensive and has heat resistance, the present inventors have improved the fluidity and the viscosity index while taking advantage of the characteristics of the aromatic ester, We thought we could get a base oil.
Therefore, as a result of intensive studies to achieve the above problems, the present inventors have achieved a predetermined effect including a grease base oil composed of an aromatic ester having a specific structure, a thickener, and an antioxidant. As a result, the present invention has been completed based on this finding.

That is, this invention provides the grease base oil of the following items, and the grease composition containing it.

(Claim 1)
General formula (1)
[Wherein, R ¹ and R ² are the same or different and each represents a linear or branched alkyl group having 4 to 12 carbon atoms. ]
Benzenedicarboxylic acid diester represented by the formula (2), and the two or more benzenedicarboxylic acid diesters include at least ^one of R ¹ and R ² represented by an n-nonyl group Grease base oil containing diester.

(Section 2)
Ratio of benzene dicarboxylic acid diester R ¹ and R ² at least one is represented by n- nonyl group, at least 50 wt% based on the total weight of the benzene dicarboxylic acid diesters, grease according to claim 1 Base oil.

(Section 3)
Item 2 or 2, wherein the two or more benzenedicarboxylic acid diesters include a benzenedicarboxylic acid diester in which at least ^one of R ¹ and R ² in the general formula (1) is a branched alkyl group having 9 carbon atoms. Item 3. The grease base oil according to Item 2.

(Section 4)
The benzenedicarboxylic acid diester represented by the general formula (1)
General formula (2)
[Wherein, R ¹ and R ² are the same or different and each represents a linear or branched alkyl group having 4 to 12 carbon atoms. ]
Item 4. The grease base oil according to any one of Items 1 to 3, which is a phthalic acid diester represented by:

(Section 5)
Item 5. The grease base oil according to any one of Items 1 to 4, wherein two or more benzenedicarboxylic acid diesters have a viscosity index of 80 to 130.

(Claim 6)
General formula (3)
[Wherein, R ³ and R ⁴ are the same or different and each represents a hydrogen atom or an alkyl group having 1 to 2 carbon atoms. ]
A benzenedicarboxylic acid derivative or phthalic anhydride represented by
A grease base oil containing a benzenedicarboxylic acid diester obtained by reacting n-nonanol and a linear or branched aliphatic alcohol having 4 to 12 carbon atoms (excluding n-nonanol).

(Claim 7)
Item 7. A grease composition comprising the grease base oil according to any one of Items 1 to 6, a thickener, and an antioxidant.

(Section 8)
The total content of the grease base oil, thickener and antioxidant does not exceed 100% by weight in the grease composition, and 60 to 95% by weight of grease base oil, 2 to 40% by weight of thickener and Item 8. The grease composition according to Item 7, comprising 0.1 to 10% by weight of an antioxidant.

(Claim 9)
Item 7 or further containing one or more of a metal detergent, an ashless dispersant, an extreme pressure agent, a metal deactivator, a corrosion inhibitor, a hue stabilizer, a rust inhibitor, a thickener, and an oily agent Item 9. The grease composition according to Item 8.

ADVANTAGE OF THE INVENTION According to this invention, the grease base oil excellent in heat-resistant oxidation stability, low-temperature fluidity | liquidity, and a viscosity-temperature characteristic, and a grease composition with favorable heat resistance, oxidation stability, and abrasion resistance can be obtained.

The grease base oil of the present invention contains two or more benzenedicarboxylic acid diesters represented by the above general formula (1), and the two or more benzenedicarboxylic acid diesters include R ¹ in the general formula (1). And R ² comprises an ester compound containing a benzenedicarboxylic acid diester represented by an n-nonyl group, and the grease composition further comprises a grease base oil, a thickener and an antioxidant according to the present invention. It is characterized by containing.

[Benzene dicarboxylic acid diester]
The benzene dicarboxylic acid diester used in the grease base oil of the present invention contains two or more benzene dicarboxylic acid diesters represented by the general formula (1), and the two or more benzene dicarboxylic acid diesters have a general formula. In (1), at least ^one of R ¹ and R ² is a mixture containing a benzenedicarboxylic acid diester represented by an n-nonyl group.

The content ratio of benzene dicarboxylic acid diester in which at least ^one of R ¹ and R ² in general formula (1) is represented by an n-nonyl group is preferably relative to the total amount of two or more benzene dicarboxylic acid diesters. 50% or more, more preferably 50 to 98%, particularly 70 to 95% is recommended.

The substitution positions of ^two alkyloxycarbonyl groups (that is, —COOR ¹ , —COOR ² : alkyl ester groups) on the benzene ring in the general formula (1) are 1,2-position, 1,3-position and 1, There is a 4-position, preferably the 1,2-position (adjacent position) is recommended. By adopting the 1,2-position (adjacent position) as the substitution position, a tendency to further improve the hydrolysis resistance of the benzenedicarboxylic acid diester itself is recognized, and further, the grease base oil of the present invention, It also has a positive effect on improving the water resistance of the grease composition.

R ¹ and R ^{2 in} the general formula (1) are the same or different and are each a linear or branched alkyl group having 4 to 12 carbon atoms, preferably a linear chain having 7 to 11 carbon atoms. Or a branched alkyl group, especially an n-nonyl group or a branched alkyl group having 9 carbon atoms is recommended.

As the alkyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group Linear alkyl group, 2-methyl-1-propyl group, 2-butyl group, 2-methyl-2-propyl group having 4 carbon atoms; 3-methyl-1-butyl group, 2- Pentanol, 3-pentyl group, 2-methyl-1-butyl group, 2-methyl-2-butyl group, 3-methyl-2-butyl group, 2,2-dimethyl-1-propyl group having 5 carbon atoms Branched alkyl group; branched chain having 6 carbon atoms such as 4-methyl-1-pentyl group, 2-hexyl group, 3-hexyl group, 2-methyl-1-pentyl group, 2-ethyl-1-butyl group Alkyl group; 5-methyl-1-hexyl group, 2-hexyl C7 branched alkyl groups such as til, 3-heptyl, 4-heptyl, 2-methyl-1-hexyl, 2-methyl-3-hexyl, 2-ethyl-1-pentyl A branched alkyl group having 8 carbon atoms such as 6-methyl-1-heptyl group, 2-octyl group, 3-octyl group, 2-methyl-1-heptyl group, 2-ethyl-1-hexyl group; 7 -Methyl-1-octyl group, 2-nonyl group, 3-nonyl group, 2-methyl-1-octyl group, 3-methyl-1-octyl group, 4-methyl-1-octyl group, 5-methyl-1 -Octyl group, 6-methyl-1-octyl group, 2-ethyl-1-heptyl group, 2,4-dimethyl-1-heptyl group, 2,5-dimethyl-1-heptyl group, 4,6-dimethyl- 1-heptyl group, 2,6-dimethyl-4-heptyl group, , 5,5-trimethyl-1-hexyl group, 2,5,5-trimethyl-1-hexyl group and the like, a branched alkyl group having 9 carbon atoms; 8-methyl-1-nonyl group, 2-decyl group, 3-decyl group, 2-methyl-1-nonyl group, 2-ethyl-1-octyl group, 2-propyl-1-heptyl group, 2,7-dimethyl-1-octyl group, 2,6-dimethyl-2 -Octyl group, 2,4-dimethyl-1-octyl group, 3,7-dimethyl-1-octyl group, 3,6-dimethyl-3-octyl group, 4-methyl-2-propyl-1-hexyl group, 5-methyl-2-propyl-1-hexyl group, 2- (1-methylethyl) -4-methyl-1-hexyl group, 2- (1-methylethyl) -5-methyl-1-hexyl group, etc. Examples thereof include a branched alkyl group having 10 carbon atoms.

The production method of the benzenedicarboxylic acid diester according to the present invention is not particularly limited to the production method as long as the target product is obtained. For example, (i) a predetermined benzenedicarboxylic acid component (phthalic acid, isophthalic acid, terephthalic acid, their anhydrides, chlorides, etc.) and a predetermined alcohol component (C4-C12 aliphatic saturated alcohol, ester formation thereof) And (ii) an ester according to a conventional method, preferably in an inert gas atmosphere such as nitrogen, in the presence of an esterification catalyst or in the absence of a catalyst with heating and stirring. Heating in the presence of a transesterification catalyst in a conventional manner, preferably in an inert gas atmosphere such as nitrogen, with a predetermined acidic component (a C4-C12 aliphatic saturated alcohol, its ester-forming derivative) as a forming derivative Examples thereof include a method of adjusting by carrying out a transesterification reaction while stirring.

As the predetermined alcohol component used for obtaining the benzenedicarboxylic acid diester according to the present invention, n-nonanol and a linear or branched aliphatic saturated alcohol having 4 to 12 carbon atoms (excluding n-nonanol) are excluded. The linear or branched aliphatic saturated alcohol having 4 to 12 carbon atoms is preferably a linear aliphatic saturated alcohol having 7 to 11 carbon atoms, more preferably a branched chain having 9 carbon atoms. An embodiment in which an aliphatic saturated alcohol is included as an essential component is recommended.

Specific examples of the linear or branched aliphatic saturated alcohol having 4 to 12 carbon atoms (excluding n-nonanol) include n-butanol, n-pentanol, n-hexanol, n-heptanol, n-octanol, n-decanol, n-undecanol, n-dodecanol linear aliphatic saturated alcohol, 2-methyl-1-propanol, 2-butanol, 2-methyl-2-propanol branched chain of 4 carbon atoms A saturated aliphatic alcohol; 3-methyl-1-butanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 2-methyl-2-butanol, 3-methyl-2-butanol, 2, 5-dimethyl branched aliphatic saturated alcohol of 2-dimethyl-1-propanol; 4-methyl-1-pentanol, 2-hexanol, -C6-C6 branched aliphatic saturated alcohols such as hexanol, 2-methyl-1-pentanol, 2-ethyl-1-butanol; 5-methyl-1-hexanol, 2-heptanol, 3-heptanol, 4 -C7 branched aliphatic saturated alcohols such as heptanol, 2-methyl-1-hexanol, 2-methyl-3-hexanol, 2-ethyl-1-pentanol; 6-methyl-1-heptanol, 2 -C8 branched aliphatic saturated alcohols such as octanol, 3-octanol, 2-methyl-1-heptanol, 2-ethyl-1-hexanol; 7-methyl-1-octanol, 2-nonanol, 3- Nonanol, 2-methyl-1-octanol, 3-methyl-1-octanol, 4-methyl-1-octanol, 5-methyl- -Octanol, 6-methyl-1-octanol, 2-ethyl-1-heptanol, 2,4-dimethyl-1-heptanol, 2,5-dimethyl-1-heptanol, 4,6-dimethyl-1-heptanol, 2 Branched aliphatic saturated alcohols having 9 carbon atoms such as 1,6-dimethyl-4-heptanol, 3,5,5-trimethyl-1-hexanol, 2,5,5-trimethyl-1-hexanol; 1-nonanol, 2-decanol, 3-decanol, 2-methyl-1-nonanol, 2-ethyl-1-octanol, 2-propyl-1-heptanol, 2,7-dimethyl-1-octanol, 2,6- Dimethyl-2-octanol, 2,4-dimethyl-1-octanol, 3,7-dimethyl-1-octanol, 3,6-dimethyl-3-oct Tanol, 4-methyl-2-propyl-1-hexanol, 5-methyl-2-propyl-1-hexanol, 2- (1-methylethyl) -4-methyl-1-hexanol, 2- (1-methylethyl) And C10 branched aliphatic saturated alcohols such as -5-methyl-1-hexanol.

As the aliphatic saturated alcohol, commercially available products, reagents, those prepared by known synthesis methods, and the like can be used. For example, as a known synthesis method of a linear aliphatic saturated alcohol, a method of producing a fatty acid (or methyl ester) by hydrogen reduction, or a hydroformylation reaction from an α-olefin, carbon monoxide and hydrogen to form an aldehyde And a method in which the aldehyde is hydrogenated and reduced to an alcohol.

Examples of commercially available products include “Conol 10WS” and “Conol 1098” (product name, manufactured by Shin Nippon Rika Co., Ltd.). Also, a mixture such as “lineball 9” (product name, manufactured by Shell Chemicals, composition: a mixture of 70% or more of n-nonanol and 30% or less of 2-methyl-1-octanol), which is mainly composed of n-nonanol. Alcohol is a commercially available product that can be directly used for the esterification reaction. For example, a mixed alcohol mainly composed of a linear aliphatic saturated alcohol such as the above-mentioned “lineball 9” is (1) an aldehyde having 9 carbon atoms by hydroformylation reaction of 1-octene, carbon monoxide and hydrogen. It can be produced by a production process comprising a production step and (2) a step of hydrogenating an aldehyde having 9 carbon atoms to reduce it to an alcohol. In the hydroformylation reaction as the step (1), for example, an aldehyde having 9 carbon atoms can be produced by reacting 1-octene, carbon monoxide and hydrogen in the presence of a cobalt catalyst or a rhodium catalyst. In addition, the hydrogenation in step (2) may be reduced to an alcohol by hydrogenating an aldehyde having 9 carbon atoms with hydrogen pressurization in the presence of a noble metal catalyst such as a nickel catalyst or a palladium catalyst. it can.

Known synthetic methods for branched aliphatic saturated alcohols include, for example, a method in which propylene is hydroformylated to form butyraldehyde and hydrogenated after the aldol condensation reaction to prepare 2-ethylhexanol, or isobutylene is a dimer. Hydroformylation of diisobutylene obtained by hydrogenation (dimerization reaction) followed by hydrogenation to prepare 3,5,5-trimethyl-1-hexanol, and hydroformylation obtained by trimerization of propylene (Oxo method) followed by hydrogenation to prepare a branched decanol (wherein the decanol is a mixture of a plurality of isomers having methyl branches, including 8-methyl-1-nonanol, In the case of such a mixture, it is called “isodecanol” and represents a branched saturated aliphatic alcohol. That.), And the like.

In other words, starting from lower olefins such as propylene, n-butylene and isobutylene, dimerization reaction, trimerization reaction, hydroformylation reaction (oxo method), aldol condensation reaction, hydrogenation reaction (reduction of olefin, aldehyde group, etc.) ) And the like, as appropriate, to prepare a branched saturated aliphatic alcohol having a relatively large total carbon number (for example, 8 or more carbon atoms). Depending on the combination of starting materials and reaction method, it may not be a single compound but a mixture of branched saturated aliphatic monoalcohol isomers having the same carbon number and different branched states, such as “isodecanol”. is there. When the obtained alcohol is a mixture of isomers, the isomers can be obtained by separation using a separation method such as rectification.

Examples of main commercial products include 3-methyl-1-hexanol, 5-methyl-1-hexanol, 3-methyl-1-heptanol, 5-methyl-1-heptanol, 2-ethyl-1-hexanol, “ "Octanol" (product name, manufactured by KH Neochem), 3,5,5-trimethyl-1-hexanol, "Nonanol" (product name, manufactured by KH Neochem), 7-methyl-1-octanol, "oxocol 900" ( Product name, manufactured by KH Neochem), “Diadol 9” (product name, manufactured by Mitsubishi Chemical), “Isononanol” (product name, manufactured by Mitsubishi Chemical), “Exaal 9” (product name, manufactured by Exxon), 2 -Ethyl-1-octanol, 8-methyl-1-nonanol, “decanol” (product name, manufactured by KH Neochem) and the like.

Among commercially available products that are industrially available, there is a mixture of a plurality of isomers having methyl branches. In that case, in the present specification and claims, “iso” is added to express the alcohol. And R ¹ and R ² in the general formula (1) of the corresponding alcohol are referred to as “isoalkyl groups” to express the phthalic acid diester. For example, in the case of “isononanol”, it means a mixture of isomers having a total carbon number of 9 and different branching states (a mixture containing a plurality of isomers having different positions where methyl branches are present). R ¹ and R ^{2 in} the formula (1) are represented as “isononyl group”.

In addition to the aliphatic saturated alcohol having 4 to 12 carbon atoms, the alcohol component may be an ester-forming derivative such as an alcohol component in an ester form of a lower fatty acid and the saturated aliphatic alcohol (for example, acetate ester, propionate ester). Etc.) can also be used to obtain the benzenedicarboxylic acid diester according to the present invention by a transesterification reaction. In the esterification reaction or transesterification reaction, the saturated aliphatic monoalcohol or the ester-forming derivative may be used alone or in combination of two or more.

In addition to the benzenedicarboxylic acid, the acid component may be an ester-forming derivative such as an anhydride or chloride of benzenedicarboxylic acid, an active ester such as an ester of benzenedicarboxylic acid and a lower alcohol, or an aryl ester. Ingredients are exemplified. In the esterification reaction or transesterification reaction, the benzenedicarboxylic acid or ester-forming derivative can be used alone or in combination of two or more.

When the esterification reaction is performed between the alcohol component and the acid component, the alcohol component is, for example, 2 to 5 mol, preferably 2.01 to 3 mol, particularly 2.02 to 2 mol per mol of the acid component. It is preferably used in a range of 5 moles (in other words, 1 to 2.5 equivalents, preferably 1.005 to 1.5 equivalents, particularly 1.01 to 1.25 equivalents per 1 equivalent of the acid component). Preferably used).

Examples of the catalyst used in the esterification reaction or transesterification reaction include mineral acids, organic acids, Lewis acids, and alkali metals. More specifically, examples of the mineral acid include sulfuric acid, hydrochloric acid, and phosphoric acid, examples of the organic acid include p-toluenesulfonic acid and methanesulfonic acid, and examples of the Lewis acid include aluminum derivatives, tin derivatives, and titanium. Derivatives, lead derivatives, and zinc derivatives are exemplified. Examples of alkali metals include sodium alkoxide, potassium alkoxide, sodium hydroxide, potassium hydroxide, and the like, and one or more of these can be used in combination. .

Among them, p-toluenesulfonic acid, tetraalkyl titanate having 3 to 8 carbon atoms, titanium oxide, titanium hydroxide, sodium alkoxide having 1 to 4 carbon atoms, sodium hydroxide, tin having 3 to 12 carbon atoms, oxidation Tin, tin hydroxide, zinc oxide, zinc hydroxide, lead oxide, lead hydroxide, aluminum oxide and aluminum hydroxide are particularly preferred. The amount used thereof is, for example, 0.01 wt% to 5.0 wt%, preferably 0.02 wt% to 4.0 wt%, particularly with respect to the total weight of the acid component and alcohol component that are raw materials for ester synthesis. It is preferable to use 0.03% to 3.0% by weight.

Examples of the reaction temperature include 100 ° C to 230 ° C, and the reaction is usually completed in 3 hours to 30 hours.

In the esterification reaction, if necessary, water entraining agents (azeotropic action, entraining action, etc.) such as benzene, toluene, xylene, cyclohexane, etc. are used to promote the distillation of water produced as a by-product of the reaction. It is possible to use.

Also, when oxygenated organic compounds such as oxides, peroxides, and carbonyl compounds are produced by oxidative degradation of raw materials, produced esters and organic solvents (water entraining agents) during the esterification reaction, the heat resistance, weather resistance, etc. are adversely affected. For this reason, it is desirable to carry out the reaction under normal or reduced pressure in an inert gas atmosphere such as nitrogen gas or in an inert gas stream.

The following steps are exemplified as the step of post-treating the “esterified crude product” obtained after the reaction. For example, a step of distilling off excess raw materials that can be distilled under reduced pressure or normal pressure under reduced pressure or normal pressure, washing with an aqueous alkali solution (neutralization) when the raw material-derived carboxylic acid component remains, and Examples include a step of washing with water, a step of purification by extraction operation such as liquid-liquid extraction, a step of adsorption purification using an adsorbent, and the like. It is preferable to combine these steps as appropriate and purify the esterified crude product by post-treatment.

In the case of performing washing (neutralization) with the alkaline aqueous solution, examples of the washing liquid include alkaline aqueous solutions such as sodium hydroxide, potassium hydroxide, lithium hydroxide, and sodium carbonate. The alkali concentration is not particularly limited, but is preferably about 0.5 to 20% by weight. The amount of the alkaline aqueous solution used is recommended to be equivalent to the total acid value of the esterified crude product after completion of the reaction or an amount that is appropriately excessive. And it is preferable to repeat washing | cleaning operation by water with respect to the washing | cleaning material after alkali washing (neutralization) until the water layer of washing water becomes neutral.

Examples of the adsorbent used for the adsorption purification include activated carbon, activated clay, activated alumina, hydrotalcite, silica gel, silica alumina, zeolite, magnesia, calcia, and diatomaceous earth.

The acid value of the benzenedicarboxylic acid diester (mixture) 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, a tendency to further improve the heat resistance of the benzenedicarboxylic acid diester itself is recognized. In such a preferable range, the heat resistance oxidation stability of the lubricating oil of the present invention is also positively affected. give. As a method of reducing the acid value, a method of sufficiently advancing the reaction, a method of neutralizing and washing with an alkali component in a post-treatment step (a step of washing with the above alkaline aqueous solution (neutralization) and washing with water) And the like.

The hydroxyl value of the benzenedicarboxylic acid diester (mixture) 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 hygroscopic property of the benzenedicarboxylic acid diester itself is lowered and the heat resistance tends to be further improved. In such a preferable range, the water resistance and heat oxidation resistance of the lubricating oil of the present invention are observed. It also has a positive effect on stability. As a method of reducing the hydroxyl value, a method of sufficiently advancing the reaction or a method of distilling off a monoalcohol component in a post-treatment step under reduced pressure (the above distillable excess raw materials etc. under reduced pressure or normal pressure) And the like).

As described above, the grease base oil of the present invention uses two or more benzene dicarboxylic acid diesters, and at least one of the two alkyl ester groups is an n-nonyl ester group ( That is, it is essential to include a benzenedicarboxylic acid diester represented by n-nonyloxycarbonyl group.

Examples of the benzene dicarboxylic acid diester in which at least one of the two alkyl ester groups is represented by an n-nonyl ester group include, for example, di (n-nonyl) phthalate, di (n-nonyl) isophthalate, and terephthalate. Acid di (n-nonyl), mixed ester obtained from phthalic acid and n-nonanol and 2-methyl-1-propanol, mixed group obtained from phthalic acid and n-nonanol and 3-methyl-1-butanol Ester, mixed ester obtained from phthalic acid and n-nonanol and 4-methyl-1-pentanol, mixed group ester obtained from phthalic acid and n-nonanol and 5-methyl-1-hexanol, phthalic acid and Mixed ester obtained from n-nonanol and 2-methyl-1-hexanol, phthalic acid and n-nonanol and 6 Mixed group ester obtained from methyl-1-heptanol, mixed group ester obtained from phthalic acid and n-nonanol and 2-ethyl-1-hexanol, phthalic acid and n-nonanol and 7-methyl-1-octanol Mixed ester obtained from phthalic acid, n-nonanol and 2-methyl-1-octanol, mixed ester obtained from phthalic acid, n-nonanol and isononanol, phthalic acid and n- From mixed ester obtained from nonanol and 8-methyl-1-nonanol, mixed ester obtained from phthalic acid and n-nonanol and isodecanol, from phthalic acid and n-nonanol and 3,5,5-trimethylhexanol The resulting mixed ester, isophthalic acid and n-nonanol and 2-methyl-1- Mixed ester obtained from ropanol, mixed ester obtained from isophthalic acid and n-nonanol and 3-methyl-1-butanol, obtained from isophthalic acid and n-nonanol and 4-methyl-1-pentanol Mixed group ester, mixed group ester obtained from isophthalic acid and n-nonanol and 5-methyl-1-hexanol, mixed group ester obtained from isophthalic acid, n-nonanol and 2-methyl-1-hexanol, isophthalic acid , N-nonanol and 6-methyl-1-heptanol, mixed ester obtained from isophthalic acid and n-nonanol and 2-ethyl-1-hexanol, isophthalic acid and n-nonanol and 7 -Mixyl ester obtained from methyl-1-octanol, isophthalic acid and mixed ester obtained from n-nonanol and 2-methyl-1-octanol, mixed ester obtained from isophthalic acid and n-nonanol and isononanol, isophthalic acid and n-nonanol and 8-methyl-1-nonanol Mixed group ester obtained from isophthalic acid and n-nonanol and isodecanol, mixed group ester obtained from isophthalic acid and n-nonanol and 3,5,5-trimethylhexanol, terephthalic acid and n Mixed ester obtained from nonanol and 2-methyl-1-propanol, mixed ester obtained from terephthalic acid and n-nonanol and 3-methyl-1-butanol, terephthalic acid and n-nonanol and 4-methyl -1-pentanol and a mixed group ester obtained from Mixed group ester obtained from phthalic acid and n-nonanol and 5-methyl-1-hexanol, mixed group ester obtained from terephthalic acid and n-nonanol and 2-methyl-1-hexanol, terephthalic acid and n-nonanol And 6-methyl-1-heptanol, mixed ester obtained from terephthalic acid and n-nonanol and 2-ethyl-1-hexanol, terephthalic acid and n-nonanol and 7-methyl-1 -Mixed ester obtained from octanol, mixed ester obtained from terephthalic acid and n-nonanol and 2-methyl-1-octanol, mixed ester obtained from terephthalic acid, n-nonanol and isononanol, terephthalic acid And n-nonanol and 8-methyl-1-nonanol Mixed ester obtained from terephthalic acid and n-nonanol and isodecanol, mixed ester obtained from terephthalic acid and n-nonanol and 3,5,5-trimethylhexanol, phthalic acid and n-nonanol And a mixed ester obtained from n-butanol, a mixed ester obtained from phthalic acid and n-nonanol and n-pentanol, a mixed ester obtained from phthalic acid, n-nonanol and n-hexanol, phthalate Mixed ester obtained from acid and n-nonanol and n-octanol, Mixed ester obtained from phthalic acid and n-nonanol and n-decanol, Mixed obtained from phthalic acid and n-nonanol and n-undecanol From the base esters, phthalic acid and n-nonanol and n-dodecanol Mixed ester obtained, mixed ester obtained from isophthalic acid and n-nonanol and n-butanol, mixed ester obtained from isophthalic acid and n-nonanol and n-pentanol, isophthalic acid and n-nonanol and Mixed ester obtained from n-hexanol, mixed ester obtained from isophthalic acid and n-nonanol and n-octanol, mixed ester obtained from isophthalic acid, n-nonanol and n-decanol, isophthalic acid and Mixed ester obtained from n-nonanol and n-undecanol, Mixed ester obtained from isophthalic acid and n-nonanol and n-dodecanol, Mixed ester obtained from terephthalic acid, n-nonanol and n-butanol Terephthalic acid and n-nonanol and n-pen Mixed ester obtained from terephthalic acid, mixed ester obtained from terephthalic acid and n-nonanol and n-hexanol, mixed ester obtained from terephthalic acid, n-nonanol and n-octanol, terephthalic acid and n- Mixed ester obtained from nonanol and n-decanol, Mixed ester obtained from terephthalic acid and n-nonanol and n-undecanol, Mixed ester obtained from terephthalic acid, n-nonanol and n-dodecanol, etc. Is exemplified. Moreover, as a specific example of the benzene dicarboxylic acid diester represented by an alkyl group in which neither of the two alkyl ester groups contains an n-nonyl ester group among the benzene dicarboxylic acid diester, for example, phthalic acid di (2- Methylpropyl), di (3-methylbutyl) phthalate, di (4-methylpentyl) phthalate, di (5-methylhexyl) phthalate, di (6-methylheptyl) phthalate, di (2-ethylhexyl) phthalate ), Di (7-methyloctyl) phthalate, di (2-methyloctyl) phthalate, di (isononyl) phthalate, di (8-methylnonyl) phthalate, di (isodecyl) phthalate, di (3 phthalate) , 5,5-trimethylhexyl), di (2-methylpropyl) isophthalate, di (3-methylbutyl) isophthalate, isophthalate Di (4-methylpentyl) acid, di (5-methylhexyl) isophthalate, di (6-methylheptyl) isophthalate, di (2-ethylhexyl) isophthalate, di (isononyl) isophthalate, di (isodecyl) isophthalate ), Di (3,5,5-trimethylhexyl) isophthalate, di (2-methylpropyl) terephthalate, di (3-methylbutyl) terephthalate, di (4-methylpentyl) terephthalate, di (5 terephthalate) -Methylhexyl), di (6-methylheptyl) terephthalate, di (2-ethylhexyl) terephthalate, di (isononyl) terephthalate, di (isodecyl) terephthalate, di (3,5,5-trimethylhexyl terephthalate) ), Di (n-butyl) orthophthalate, di (n-pentyl) orthophthalate, orthophthalate Di (n-hexyl) acid, di (n-heptyl) orthophthalate, di (n-octyl) orthophthalate, di (n-decyl) orthophthalate, di (n-undecyl) orthophthalate, di (n-undecyl) orthophthalate Dodecyl), di (n-butyl) isophthalate, di (n-pentyl) isophthalate, di (n-hexyl) isophthalate, di (n-heptyl) isophthalate, di (n-octyl) isophthalate, isophthalic acid Di (n-decyl), di (n-undecyl) isophthalate, di (n-dodecyl) isophthalate, di (n-butyl) terephthalate, di (n-pentyl) terephthalate, di (n-hexyl) terephthalate ), Di (n-heptyl) terephthalate, di (n-octyl) terephthalate, di (n-decyl) terephthalate, di (n-undecyl) terephthalate , Terephthalic acid di (n-dodecyl), mixed ester obtained from phthalic acid and n-octanol and 2-methyl-1-propanol, phthalic acid obtained from n-octanol and 3-methyl-1-butanol Mixed group ester, mixed group ester obtained from phthalic acid and n-octanol and 4-methyl-1-pentanol, mixed group ester obtained from phthalic acid, n-octanol and 5-methyl-1-hexanol, phthalate Mixed ester obtained from acid and n-octanol and 2-methyl-1-hexanol, mixed ester obtained from phthalic acid and n-octanol and 6-methyl-1-heptanol, phthalic acid and n-octanol and Mixed ester obtained from 2-ethyl-1-hexanol, phthalic acid and n-octanol and 7 Mixed ester obtained from methyl-1-octanol, mixed ester obtained from phthalic acid and n-octanol and 2-methyl-1-octanol, mixed ester obtained from phthalic acid, n-octanol and isononanol Mixed ester obtained from phthalic acid and n-octanol and 8-methyl-1-nonanol, mixed ester obtained from phthalic acid and n-octanol and isodecanol, phthalic acid and n-octanol and 3,5,5 From mixed ester obtained from 5-trimethylhexanol, mixed ester obtained from isophthalic acid and n-octanol and 2-methyl-1-propanol, from isophthalic acid and n-octanol and 3-methyl-1-butanol The resulting mixed ester, isophthalic acid and n-octano And 4-methyl-1-pentanol, mixed ester obtained from isophthalic acid and n-octanol and 5-methyl-1-hexanol, isophthalic acid and n-octanol and 2-methyl- Mixed group ester obtained from 1-hexanol, mixed group ester obtained from isophthalic acid and n-octanol and 6-methyl-1-heptanol, obtained from isophthalic acid, n-octanol and 2-ethyl-1-hexanol Mixed ester obtained from isophthalic acid and n-octanol and 7-methyl-1-octanol, mixed ester obtained from isophthalic acid and n-octanol and 2-methyl-1-octanol, isophthalic acid Mixed groups obtained from acids and n-octanol and isononanol Esters, mixed ester obtained from isophthalic acid and n-octanol and 8-methyl-1-nonanol, mixed ester obtained from isophthalic acid and n-octanol and isodecanol, isophthalic acid and n-octanol and 3,5 , 5-trimethylhexanol and mixed ester obtained from terephthalic acid and n-octanol and 2-methyl-1-propanol, terephthalic acid and n-octanol and 3-methyl-1-butanol Mixed group ester obtained from terephthalic acid, n-octanol and 4-methyl-1-pentanol, mixed group ester obtained from terephthalic acid, n-octanol and 5-methyl-1-hexanol Esters, terephthalic acid and n-octanol and 2- Mixed group ester obtained from til-1-hexanol, mixed group ester obtained from terephthalic acid and n-octanol and 6-methyl-1-heptanol, terephthalic acid and n-octanol and 2-ethyl-1-hexanol Mixed ester obtained from terephthalic acid, n-octanol and 7-methyl-1-octanol, mixed ester obtained from terephthalic acid, n-octanol and 2-methyl-1-octanol A mixed ester obtained from terephthalic acid and n-octanol and isononanol, a mixed ester obtained from terephthalic acid and n-octanol and 8-methyl-1-nonanol, obtained from terephthalic acid and n-octanol and isodecanol Mixed group ester, terephthalic acid and Mixed ester obtained from octanol and 3,5,5-trimethylhexanol, mixed ester obtained from phthalic acid and n-decanol and 2-methyl-1-propanol, phthalic acid and n-decanol and 3- Mixed group esters obtained from methyl-1-butanol, mixed group esters obtained from phthalic acid and n-decanol and 4-methyl-1-pentanol, phthalic acid and n-decanol and 5-methyl-1-hexanol Mixed ester obtained from phthalic acid, mixed ester obtained from n-decanol and 2-methyl-1-hexanol, mixed group obtained from phthalic acid and n-decanol and 6-methyl-1-heptanol Ester, mixed group ester obtained from phthalic acid and n-decanol and 2-ethyl-1-hexanol, Mixed group ester obtained from phthalic acid and n-decanol and 7-methyl-1-octanol, Mixed group ester obtained from phthalic acid and n-decanol and 2-methyl-1-octanol, phthalic acid and n-decanol And mixed ester obtained from isononanol, mixed ester obtained from phthalic acid and n-decanol and 8-methyl-1-nonanol, mixed ester obtained from phthalic acid and n-decanol and isodecanol, phthalic acid And n-decanol and 3,5,5-trimethylhexanol, mixed ester obtained from isophthalic acid and n-decanol and 2-methyl-1-propanol, isophthalic acid and n-decanol and Mixed ester obtained from 3-methyl-1-butanol, isophthalic acid Mixed ester obtained from n-decanol and 4-methyl-1-pentanol, mixed ester obtained from isophthalic acid and n-decanol and 5-methyl-1-hexanol, isophthalic acid and n-decanol and 2 -Mixyl ester obtained from methyl-1-hexanol, mixed ester obtained from isophthalic acid and n-decanol and 6-methyl-1-heptanol, isophthalic acid, n-decanol and 2-ethyl-1-hexanol A mixed group ester obtained from isophthalic acid, n-decanol and 7-methyl-1-octanol, a mixed group ester obtained from isophthalic acid, n-decanol and 2-methyl-1-octanol Mixtures obtained from esters, isophthalic acid and n-decanol and isononanol Esters, mixed ester obtained from isophthalic acid and n-decanol and 8-methyl-1-nonanol, mixed ester obtained from isophthalic acid and n-decanol and isodecanol, isophthalic acid and n-decanol and 3,5 , 5-trimethylhexanol and mixed ester obtained from terephthalic acid and n-decanol and 2-methyl-1-propanol, terephthalic acid and n-decanol and 3-methyl-1-butanol Mixed ester obtained from terephthalic acid, n-decanol and 4-methyl-1-pentanol, mixed ester obtained from terephthalic acid, n-decanol and 5-methyl-1-hexanol Esters, terephthalic acid and n-decanol and 2-methyl-1-hex Mixed ester obtained from sanol, mixed ester obtained from terephthalic acid and n-decanol and 6-methyl-1-heptanol, mixed obtained from terephthalic acid and n-decanol and 2-ethyl-1-hexanol A mixed ester obtained from a base ester, terephthalic acid and n-decanol and 7-methyl-1-octanol, a mixed ester obtained from terephthalic acid and n-decanol and 2-methyl-1-octanol, terephthalic acid and Mixed group ester obtained from n-decanol and isononanol, Mixed group ester obtained from terephthalic acid and n-decanol and 8-methyl-1-nonanol, Mixed group ester obtained from terephthalic acid and n-decanol and isodecanol Terephthalic acid and n-decanol and 3,5,5- Mixed group ester obtained from limethylhexanol, mixed group ester obtained from phthalic acid and 2-methyl-1-octanol and n-butanol, obtained from phthalic acid and 2-methyl-1-octanol and n-pentanol Mixed group ester, mixed group ester obtained from phthalic acid and 2-methyl-1-octanol and n-hexanol, mixed group ester obtained from phthalic acid and 2-methyl-1-octanol and n-heptanol, phthalic acid and 2 A mixed ester obtained from methyl-1-octanol and n-undecanol, a mixed ester obtained from phthalic acid and 2-methyl-1-octanol and n-dodecanol, phthalic acid and 2-methyl-1-octanol and 2 -Mixed ester obtained from methyl-1-propanol, phthalic acid and 2-methyl Mixed ester obtained from ru-1-octanol and 4-methyl-1-pentanol, mixed ester obtained from phthalic acid and 2-methyl-1-octanol and 2-methyl-1-hexanol, phthalic acid Group ester obtained from 2-methyl-1-octanol and 5-methyl-1-hexanol, and mixed ester obtained from phthalic acid and 2-methyl-1-octanol and 2-ethyl-1-pentanol A mixed ester obtained from phthalic acid and 2-methyl-1-octanol and 2-ethyl-1-hexanol, a mixture obtained from phthalic acid and 2-methyl-1-octanol and 2-methyl-1-heptanol Group ester, phthalic acid, mixed ester obtained from 2-methyl-1-octanol and isooctanol, and phthalic acid Mixed ester obtained from 2-methyl-1-octanol and isononanol, mixed ester obtained from phthalic acid and 2-methyl-1-octanol and 3,5,5-trimethyl-1-hexanol, phthalic acid and Mixed group ester obtained from 2-methyl-1-octanol and isodecanol, Mixed group ester obtained from phthalic acid and 2-methyl-1-octanol and isoundecanol, Isophthalic acid and 2-methyl-1-octanol And a mixed group ester obtained from n-butanol, a mixed group ester obtained from isophthalic acid and 2-methyl-1-octanol and n-pentanol, obtained from isophthalic acid and 2-methyl-1-octanol and n-hexanol Mixed group esters, isophthalic acid and 2-methyl-1-octanol and n A mixed ester obtained from heptanol, a mixed ester obtained from isophthalic acid and 2-methyl-1-octanol and n-undecanol, a mixed ester obtained from isophthalic acid and 2-methyl-1-octanol and n-dodecanol, Mixed ester obtained from isophthalic acid and 2-methyl-1-octanol and 2-methyl-1-propanol, mixed group obtained from isophthalic acid and 2-methyl-1-octanol and 4-methyl-1-pentanol Esters, mixed ester obtained from isophthalic acid and 2-methyl-1-octanol and 2-methyl-1-hexanol, obtained from isophthalic acid and 2-methyl-1-octanol and 5-methyl-1-hexanol Mixed ester, isophthalic acid and 2-methyl-1-octanol Mixed ester obtained from 2-ethyl-1-pentanol, mixed ester obtained from isophthalic acid and 2-methyl-1-octanol and 2-ethyl-1-hexanol, isophthalic acid and 2-methyl- Mixed ester obtained from 1-octanol and 2-methyl-1-heptanol, Mixed ester obtained from isophthalic acid and 2-methyl-1-octanol and isooctanol, Isophthalic acid and 2-methyl-1-octanol And isononanol, a mixed group ester obtained from isophthalic acid and 2-methyl-1-octanol and 3,5,5-trimethyl-1-hexanol, isophthalic acid and 2-methyl-1-octanol And isodecanol, mixed ester, isophthalic acid and 2-methyl Mixed ester obtained from -1-octanol and isoundecanol, mixed ester obtained from terephthalic acid and 2-methyl-1-octanol and n-butanol, terephthalic acid and 2-methyl-1-octanol and n -Mixed ester obtained from pentanol, mixed group ester obtained from terephthalic acid and 2-methyl-1-octanol and n-hexanol, mixed group obtained from terephthalic acid, 2-methyl-1-octanol and n-heptanol Esters, mixed group esters obtained from terephthalic acid and 2-methyl-1-octanol and n-undecanol, mixed group esters obtained from terephthalic acid, 2-methyl-1-octanol and n-dodecanol, terephthalic acid and 2-methyl -1-octanol and 2-methyl-1-propano Mixed ester obtained from terephthalic acid, mixed ester obtained from terephthalic acid and 2-methyl-1-octanol and 4-methyl-1-pentanol, terephthalic acid, 2-methyl-1-octanol and 2-methyl- Mixed group ester obtained from 1-hexanol, mixed group ester obtained from terephthalic acid and 2-methyl-1-octanol and 5-methyl-1-hexanol, terephthalic acid and 2-methyl-1-octanol and 2- Mixed group ester obtained from ethyl-1-pentanol, mixed group ester obtained from terephthalic acid and 2-methyl-1-octanol and 2-ethyl-1-hexanol, terephthalic acid and 2-methyl-1-octanol And 2-methyl-1-heptanol, mixed ester, terephthalic acid and 2-methyl Mixed ester obtained from 1-octanol and isooctanol, mixed ester obtained from terephthalic acid and 2-methyl-1-octanol and isononanol, terephthalic acid and 2-methyl-1-octanol and 3,5,5 A mixed group ester obtained from trimethyl-1-hexanol, a mixed group ester obtained from terephthalic acid and 2-methyl-1-octanol and isodecanol, terephthalic acid, 2-methyl-1-octanol and isoundecanol And mixed group esters obtained from the above.

In the present specification and claims, the “mixed ester” means a diester in which R ¹ and R ² are composed of different alkyl groups as described in the general formula (1). For example, in the above example of “mixed ester obtained from phthalic acid and n-nonanol and 2-methyl-1-octanol”, in general formula (1), ^one of R ¹ and R ² is an n-nonyl group. And the other is a diester represented by a 2-methyloctyl group. In the present specification and claims, it may be expressed as phthalic acid (2-methyloctyl) (n-nonyl).

The kinematic viscosity at 100 ° C. of the grease base oil of the present invention is preferably 1.5 to 40 mm ² / s, more preferably 2.5 to 30 mm ² / s.

The viscosity index of the grease base oil of the present invention is preferably 80 to 160, more preferably 90 to 160.

The pour point of the grease base oil of the present invention is preferably −10 ° C. or less, more preferably −15 ° C. or less, and particularly preferably −20 ° C. or less.

The flash point of the grease base oil of the present invention is preferably 200 ° C or higher, more preferably 230 ° C or higher.

[Thickener]
Examples of the thickener used in the grease composition of the present invention include soaps such as sodium soap, lithium soap, calcium soap, calcium complex soap, aluminum complex soap, lithium complex soap, bentonite, silica airgel, sodium terephthala. Non-soap type such as mate, urea compound, polytetrafluoroethylene, boron nitride and the like can be mentioned.

Examples of the metal soap thickener include an aliphatic carboxylic acid lithium salt having a hydroxyl group such as lithium-12-hydroxystearate, an aliphatic carboxylic acid lithium salt such as lithium stearate, or a mixture thereof.

Examples of the complex metal soap thickener include a complex of a monovalent aliphatic carboxylic acid metal salt having a hydroxyl group and a divalent aliphatic carboxylic acid metal salt. Specifically, a complex lithium soap or A composite aluminum soap is exemplified.

Examples of urea compounds include alicyclic, aromatic, aliphatic, diurea, triurea, tetraurea, urea / urethane compounds and the like.

Among these, as the thickener, lithium soap, lithium complex soap and urea compound are preferable, and urea compound is particularly preferable from the viewpoint of heat resistance.

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

[Antioxidant]
Antioxidants according to the present invention include 2,6-di-tert-butyl-p-cresol, 2-tert-butyl-4-hydroxyanisole, 2,5-di-tert-butylhydroquinone, 4-hydroxymethyl -2,6-di-tert-butylphenol, 4,4'-methylenebis-2,6-di-tert-butylphenol, 2,2'-methylenebis-4-methyl-6-tert-butylphenol, tetrakis [methylene-3 -(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] phenol-based such as methane, amine-based such as N-phenyl-α-naphthylamine, p, p'-dioctyldiphenylamine, p, p'- Sulfur compounds such as dinonyldiphenylamine, mixed dialkyldiphenylamine, phenothiazine, etc. Selenium compounds such as diallyl selenide, zinc dialkyl dithiophosphate, dialkyl dithiocarbamates, quinolines, triazoles, and the like.

Among the above, 2,6-di-tert-butyl-p-cresol, 4,4′-methylenebis-2,6-di-tert-butylphenol, tetrakis [methylene-3- (3,5) are used as antioxidants. -Di-tert-butyl-4-hydroxyphenyl) propionate] methane, N-phenyl-α-naphthylamine, p, p′-dioctyldiphenylamine are preferred, and N-phenyl-α-naphthylamine, p, in particular in terms of heat resistance p′-Dioctyldiphenylamine is preferred.

These antioxidants may be used alone or in combination of two or more as appropriate, and the amount added is not particularly limited as long as a predetermined effect is exhibited.

The grease composition of the present invention is characterized by containing the grease base oil according to the present invention, a thickener and an antioxidant. The content of the grease composition is such that the total of the grease base oil, the thickener and the antioxidant does not exceed 100% by weight, and preferably, the grease base oil is 60 to 95% by weight, and the thickener 2 40% by weight and 0.1 to 10% by weight of antioxidant, more preferably 65 to 90% by weight of grease base oil, 4 to 35% by weight of thickener and 0.3 to 8% by weight of antioxidant are recommended. The

In addition to the benzenedicarboxylic acid diester according to the present invention, the grease base oil of the present invention can be used in combination with another conventionally known base oil (hereinafter referred to as “combined base oil”).

When the combined base oil is used, the amount used is 50% by weight or less, more preferably 30% by weight or less, more preferably 10%, based on the total weight of the benzenedicarboxylic acid diester according to the present invention and the combined base oil. A range of weight percent or less is recommended.

As the above-mentioned combined base oil, mineral oil (hydrocarbon oil obtained by refining petroleum), poly-α-olefin, polybutene, alkylbenzene, alkylnaphthalene, alicyclic hydrocarbon oil, synthetic hydrocarbon obtained by Fischer-Tropsch process Examples include synthetic hydrocarbon oils such as isomerized oils, animal and vegetable oils, organic acid esters other than phthalic acid diesters according to the present invention, polyalkylene glycols, polyvinyl ethers, polyphenyl ethers, alkylphenyl ethers, silicone oils, and the like. Such combined base oils can be used alone or in combination of two or more.

Examples of the mineral oil include solvent refined mineral oil, hydrorefined mineral oil, and wax isomerized oil. Usually, the kinematic viscosity at 100 ° C. is 1.0 to 25 mm ² / s, preferably 2.0 to 20.0 mm ^2. Those in the range of / s 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. ) And a copolymer having a kinematic viscosity at 100 ° C. of 1.0 to 25 mm ² / s and a viscosity index of 100 or more. Those having a viscosity index of 120 mm or more at 0.0 mm ² / s are preferable.

Examples of polybutene include those obtained by polymerizing isobutylene and those obtained by copolymerizing isobutylene with normal butylene, and generally include a wide range of those having a kinematic viscosity at 100 ° C. of 2.0 to 40 mm ² / s.

Examples of the alkyl benzene include monoalkyl benzene, dialkyl benzene, trialkyl benzene, and tetraalkyl benzene having a molecular weight of 200 to 450, which are substituted with a linear or branched alkyl group having 1 to 40 carbon atoms.

Examples of the alkyl naphthalene include monoalkyl naphthalene and dialkyl naphthalene substituted with a linear or branched alkyl group having 1 to 30 carbon atoms.

Examples of animal and vegetable oils include beef tallow, lard, palm oil, coconut oil, rapeseed oil, castor oil, sunflower oil and the like.

Examples of organic acid esters other than the benzenedicarboxylic acid diester according to the present invention include fatty acid monoesters, aliphatic dibasic acid diesters, and polyol esters.
The fatty acid monoester is obtained from an aliphatic linear or branched monocarboxylic acid having 5 to 22 carbon atoms and a linear or branched saturated or unsaturated aliphatic alcohol having 3 to 22 carbon atoms. And monoesters that can be used. Aliphatic dibasic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, nonanedioic acid, decanedioic acid Examples thereof include diesters obtained from an acid and a linear or branched saturated or unsaturated aliphatic alcohol having 3 to 22 carbon atoms. Further, as the polyol ester, neopentyl glycol such as neopentyl glycol, trimethylolpropane, pentaerythritol, ditrimethylolpropane, dipentaerythritol and the like, and linear and / or branched saturated or 3 to 22 carbon atoms or Examples thereof include polyol esters obtained from unsaturated fatty acids.
Examples of the esters other than the above 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 chain having 3 to 22 carbon atoms. Examples thereof include ester compounds with saturated or unsaturated aliphatic alcohols.

Examples of the polyalkylene glycol include a ring-opening polymer of 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 two or more types can be used. A compound in which one or both hydroxyl groups are etherified or esterified can also be used. The kinematic viscosity (40 ° C.) of the polymer is usually 5 to 1000 mm ² / s, preferably 5 to 500 mm ² / s.

Polyvinyl ether is a compound obtained by polymerization of a vinyl ether monomer, and monomers include methyl vinyl ether, ethyl vinyl ether, 2-propyl vinyl ether, 1-butyl vinyl ether, 2-methyl-1-propyl vinyl ether, 2-butyl vinyl ether, 2 -Methyl-2-propyl vinyl ether, 1-pentyl vinyl ether, 1-hexyl vinyl ether, 2-methoxyethyl vinyl ether, 2-ethoxyethyl vinyl ether and the like. The kinematic viscosity (40 ° C.) of the polymer is usually 5 to 1000 mm ² / s, preferably 5 to 500 mm ² / s.

Examples of polyphenyl ether include compounds having a structure in which meta positions of two or more aromatic rings are connected by an ether bond or a thioether bond. Specifically, bis (m-phenoxyphenyl) ether, m-bis ( m-phenoxyphenoxy) benzene, and thioethers (commonly referred to as C-ether) in which one or more of these oxygens are substituted 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 alkyl diphenyl ether substituted with one or more alkyl groups is particularly preferable.

Examples of the silicone oil include dimethyl silicone and methylphenyl silicone, and modified silicones such as long-chain alkyl silicone and fluorosilicone.

In addition to the essential components of the grease base oil, thickener and antioxidant, the grease composition according to the present invention further includes a metal detergent, an ashless dispersant, an extreme pressure agent, One or more additives such as a metal deactivator, a corrosion inhibitor, a hue stabilizer, a rust inhibitor, a thickener, and an oily agent can be appropriately blended. Although the said additive is not specifically limited as long as there exists a predetermined effect, The specific example is shown below.

Metal detergents include Ca-petroleum sulfonate, overbased Ca-petroleum sulfonate, Ca-alkyl benzene sulfonate, overbased Ca-alkyl benzene sulfonate, Ba-alkyl benzene sulfonate, over-based Ba-alkyl benzene sulfonate. Phonate, Mg-alkylbenzenesulfonate, overbased Mg-alkylbenzenesulfonate, Na-alkylbenzenesulfonate, overbased Na-alkylbenzenesulfonate, Ca-alkylnaphthalenesulfonate, overbased Ca- Metal sulfonates such as alkyl naphthalene sulfonates, Ca-phenates, overbased Ca-phenates, Ba-phenates, overbased Ba-phenates and other metal phenates, Ca-salicylate, overbased C Metal salicylates such as salicylates, Ca-phosphonates, overbased Ca-phosphonates, Ba-phosphonates, overbased Ba-phosphonates and other metal phosphonates, overbased Ca-carboxylates Etc. are exemplified. These metal detergents can be used individually or in combination of 2 or more types as appropriate. When these metal detergents are used, it is recommended that the amount used is usually 1 to 10 parts by weight, preferably 2 to 7 parts by weight, based on 100 parts by weight of the grease composition.

Examples of the ashless dispersant include polyalkenyl succinimide, polyalkenyl succinamide, polyalkenyl benzylamine, polyalkenyl succinate and the like. These ashless dispersants can be used alone or in combination of two or more. When these ashless dispersants are used, the amount used is usually 1 to 10 parts by weight, preferably 2 to 7 parts by weight, based on 100 parts by weight of the grease composition.

Examples of oily agents 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, lauryl alcohol, Aliphatic saturated and unsaturated monoalcohols such as oleyl alcohol, aliphatic saturated and unsaturated monoamines such as stearylamine and oleylamine, aliphatic saturated and unsaturated monocarboxylic amides such as lauric acid amide, oleic acid amide, batyl alcohol, Glycerol ethers such as chimyl alcohol and ceralkyl alcohol, alkyl or alkenyl polyglyceryl ethers such as lauryl polyglyceryl ether and oleyl polyglyceryl ether, di (2-ethylhexyl) monoethanolamine , Poly (alkylene oxide) alkyl or alkenyl amines such as diisotridecyl monoethanolamine adduct and the like. These oily agents may be used alone or in appropriate combination of two or more. When using these oil-based agents, it is usually recommended that the amount used be 0.01 to 5 parts by weight, preferably 0.1 to 3 parts by weight, based on 100 parts by weight of the grease composition.

Antiwear / extreme pressure agents include tricresyl phosphate, cresyl diphenyl phosphate, alkylphenyl phosphates, phosphate esters such as tributyl phosphate, dibutyl phosphate, tributyl phosphate, dibutyl phosphate, triisopropyl phosphate, etc. Phosphorous esters of these and phosphorus salts such as amine salts thereof, sulfurized fatty acids such as sulfurized fats and oils, sulfurized oleic acid, sulfurous systems such as dibenzyl disulfide, sulfurized olefin and dialkyl disulfide, Zn-dialkyldithiophosphate, Zn- Examples thereof include organometallic compounds such as dialkyldithiophosphate, Mo-dialkyldithiophosphate, and Mo-dialkyldithiocarbamate, lead naphthenate, molybdenum disulfide, and graphite. These antiwear agents can be used alone or in combination of two or more. When using these antiwear / extreme pressure agents, the amount used is usually 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the grease composition. Is desirable.

Examples of the metal deactivator include benzotriazole-based, thiadiazole-based, and gallic acid ester-based compounds. These metal deactivators can be used alone or in appropriate combination of two or more. When these metal deactivators are used, the amount used is usually 0.01 to 0.4 parts by weight, preferably 0.01 to 0.2 parts by weight, based on 100 parts by weight of the grease composition. It is recommended.

Antirust 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 Partial alcohol ester, Ca-petroleum sulfonate, Ca-alkyl benzene sulfonate, Ba-alkyl benzene sulfonate, Mg-alkyl benzene sulfonate, Na-alkyl benzene sulfonate, Zn-alkyl benzene sulfonate, Ca-alkyl naphthalene sulphate Examples thereof include metal sulfonates such as phonates, amines such as rosinamine and N-oleylsarcosine, dialkyl phosphiteamine salts, sodium nitrite and the like. These rust inhibitors can be used alone or in combination of two or more. When using these rust preventives, it is recommended that the amount used is usually 0.01 to 5 parts by weight, preferably 0.05 to 2 parts by weight, based on 100 parts by weight of the grease composition. .

Examples of the corrosion inhibitor include sodium sulfonate and sorbitan ester, and usually 0.1 to 3.0% by weight is added to the grease composition.

Examples of the hue stabilizer include substituted hydroquinone and furfural azine, and are usually added in an amount of 0.01 to 0.1% by weight in the grease composition.

The grease composition according to the present invention can be prepared by mixing a grease base oil, a thickener and an antioxidant, and, if necessary, the above additives.
For example, first a grease base oil and a thickener are simply mixed, or a thickener is formed by reacting a thickener precursor in the grease base oil, and then the thickener is added to the grease base oil. A grease base oil containing a thickener is prepared by, for example, a method of dispersing in a thickener. Next, there is exemplified a method of appropriately adding an antioxidant and, if necessary, an additive to a grease base oil containing a thickener at an appropriate temperature without any particular restriction on the order of addition.

Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited only to these examples. In Examples and Comparative Examples, various properties of the ester compound (grease base oil) and various properties of the grease composition were measured or evaluated by the following methods. Reagents were used for compounds not specifically mentioned.

(A) Composition analysis of ester compound The composition analysis of the ester compound was conducted using gas chromatography under the following conditions. The simple area ratio of the obtained gas chromatogram was used as the composition ratio of the ester compound.
<Measurement conditions>
Equipment: GC-2010 manufactured by Shimadzu Corporation
Column used: J & W TC-5 30m x 0.25mm
Column temperature: 100 to 300 ° C. (temperature rising rate 20 ° C./min)
Injection temperature / detection temperature: 300 ° C / 300 ° C
Detector: FID
Carrier gas: Helium gas flow rate: 0.97 mL / min
Split ratio: 1/50

(B) Acid value It measured based on JISK2501 (2003).

(C) Kinematic viscosity Kinematic viscosity at 40 ° C and 100 ° C was measured according to JIS K2283 (2000). However, the 0 ° C. kinematic viscosity was calculated from the viscosity-temperature relationship defined in JIS K2283 (2000).

(D) Viscosity index Calculated according to JIS K2283 (2000).
(E) Pour point Measured according to JIS K2269 (1987).

(F) Flash point Measured according to JIS K2265-4 (Cleveland open type) (2007).

(G) Heat-resistant oxidation stability test To 100 parts by weight of the grease base oil described in Table 1, 1.0 parts each of 2,6-di-tert-butyl-p-cresol and p, p′-dioctyldiphenylamine as antioxidants The grease base oil for evaluation formed by adding parts was prepared. Since the test is usually performed by adding an additive such as an antioxidant, the same additive was blended in the examples and comparative examples, and a comparative test was performed. Insert a glass test tube with an inner diameter of 33 mm and a height of 85 mm into a glass test tube with 0.2 g of the lubricating oil and steel, aluminum, and copper wires cut to a length of 2 mm, and cover the stopper. The lid does not open. A clasp was attached. The test tube was placed in an oven and heated at 190 ° C. for 20 hours. The acid value of the grease base oil for evaluation after the test was measured to determine the difference from the acid value before the oxidation test, and the difference was defined as the acid value increase value. It is determined that the smaller the acid value increase value (mgKOH / g), the better the thermal oxidation stability.
Increase in acid value (mgKOH / g) = acid value after test-acid value before test

(H) Mixed consistency The mixed consistency of the grease composition was measured under the conditions of 60 W and 25 ° C. in accordance with JIS K2220 (2003) 5.3.

(I) Dropping point The dropping point of the grease composition was measured according to JIS K2220 (2003) 5.4.

(J) Oil separation degree The oil separation degree of the grease composition was measured in accordance with JIS K2220 (2003) 5.7 under the conditions of 100 ° C and 24 hours.

(K) Acid Value Stability The oxidation stability of the grease composition was measured under the conditions of 99 ° C., 7.7 kgf / cm 2 and 100 h in accordance with JIS K2220 (2003) 5.8.

(L) Abrasion resistance The abrasion resistance of the grease composition was measured under the conditions of 40 kgf / cm ² , 1200 rpm, and 30 min in accordance with ASTM D2596-87.

[Production Example 1]
In a four-necked flask equipped with a stirrer, thermometer, and Dean-Stark water separator, 222 g (1.5 mol) of phthalic anhydride as an acid component as a raw material to be charged, and “LINEVOL9” as an alcohol component (Shell Chemicals product) 475.2 g (3.3 mol), xylene as a water entraining agent, an amount corresponding to 5% by weight (23.8 g) with respect to the raw material, and a raw material charged with a tin oxide catalyst as an esterification catalyst The amount corresponding to 0.2% by weight (0.95 g) was charged, and after nitrogen substitution, the temperature was gradually raised to 210 ° C. in a nitrogen atmosphere. While removing water produced as a by-product during the esterification reaction with a water separator, the esterification reaction is performed at normal pressure for 4 hours, and the reaction is continued for 5 hours under reduced pressure (0.02 MPa) while maintaining 210 ° C. The acid value of the reaction mixture was 1 mg KOH / g or less, and an esterified crude product was obtained. Next, post-treatment of the esterified crude product was performed. First, xylene and excess monoalcohol components are distilled off from the esterified crude product under reduced pressure conditions of 180 ° C. and 1330 Pa, 30 g of 5% aqueous sodium hydroxide solution is added to the resulting liquid residue, and the mixture is stirred at 80 ° C. for 2 hours. Neutralization. The neutralized product was repeatedly washed with water until the water layer of the washing water became neutral to obtain a liquid material. Subsequently, activated alumina was added and stirred for adsorption treatment, followed by suction filtration to obtain 595 g of benzenedicarboxylic acid diester (hereinafter referred to as “ester A”) according to the present invention. The acid value of ester A was 0.01 mgKOH / g, and the hydroxyl value was less than 1 mgKOH / g. The composition of ester A was as follows from the gas chromatogram.
Ester A;
(A) Di (2-methyloctyl) phthalate
(B) Phthalic acid (2-methyloctyl) (n-nonyl)
(C) Di (n-nonyl) phthalate
(A) / (b) / (c) = 6.6 / 11.3 / 82.1 (area%)

[Production Example 2]
In the same manner as in Production Example 2, except that the alcohol component of the raw material was replaced with 429 g (3.3 mol) of 2-ethyl-1-hexanol (manufactured by KH Neochem, product name “octanol”), phthalate di ( 2-ethylhexyl) (hereinafter referred to as “ester a”) 553 g. The acid value of ester a was 0.01 mgKOH / g, and the hydroxyl value was less than 1 mgKOH / g.

[Production Example 3]
Di (n-undecyl) phthalate was prepared in the same manner as in Production Example 2, except that the alcohol component of the raw material was replaced with 521.4 g (3.3 mol) of n-undecanol (manufactured by Tokyo Chemical Industry Co., Ltd .: Reagent). 690 g (hereinafter referred to as “ester b”) was obtained. The acid value of ester b was 0.01 mgKOH / g, and the hydroxyl value was less than 1 mgKOH / g.

[Properties of ester compound]
Table 1 shows the measurement results of the kinematic viscosity, viscosity index, flash point and pour point, and oxidation stability test of each ester compound of the above Production Example.

[Example 1]
Using ester A obtained in Production Example 1 as a grease base oil, diphenylmethane-4,4′-diisocyanate (manufactured by Tokyo Chemical Industry Co., Ltd .: Reagent) and octylamine (manufactured by Tokyo Chemical Industry Co., Ltd.): Reagent) in grease base oil to prepare a urea compound as a thickener. The urea compound was uniformly dispersed in the grease base oil so that the content of the urea compound was 30% by weight in the final grease composition. N-phenyl-α-naphthylamine (manufactured by Tokyo Kasei Kogyo Co., Ltd .: Reagent) and p, p′-dioctyldiphenylamine (manufactured by Vanderbilt, product name “Vanrube81”) are added to the thickener-containing grease. By adding 1% by weight, the grease composition of the present invention was obtained.

[Example 2]
Using ester A obtained in Production Example 1 as a grease base oil, a precursor of a thickener, 12-hydroxystearic acid (manufactured by Tokyo Chemical Industry Co., Ltd .: Reagent), and lithium hydroxide are reacted in the grease base oil. Thus, a lithium soap as a thickener was prepared. The lithium soap was uniformly dispersed in the grease base oil so that the content of the lithium soap was 12% by weight in the final grease composition. 1% by weight of N-phenyl-α-naphthylamine and p, p′-dioctyldiphenylamine was added as an antioxidant to the thickener-containing grease base oil to obtain a grease composition of the present invention.

[Example 3]
The grease composition of the present invention was prepared in the same manner as in Example 1 except that 2,6-di-t-butyl-p-cresol (manufactured by Tokyo Chemical Industry Co., Ltd .: reagent) was used as an antioxidant. Prepared.

The same method as in Example 3, except that 0.05% by weight of a benzotriazole-based compound (manufactured by BASF, product name “Irgamet39”) was added as a metal deactivator, and the ester A was changed by 67.95% by weight. Thus, the grease composition of the present invention was prepared.

[Comparative Example 1]
A grease composition outside the present invention was prepared in the same manner as in Example 1 except that the ester a obtained in Production Example 2 was used as a grease base oil.

[Comparative Example 2]
A grease composition outside the present invention was prepared in the same manner as in Example 1 except that the ester b obtained in Production Example 3 was used as a grease base oil.

[Composition and properties of grease composition]
Table 2 shows the compositions and composition ratios of the respective grease compositions of the above Examples and Comparative Examples, and the measurement results of the mixing consistency, dropping point, oil separation degree, oxidation stability and abrasion resistance.

From Table 1, it can be seen that ester A has a high viscosity index of 90 or more, has a small increase in viscosity at low temperature, and is excellent in fluidity and oxidation stability at low temperature, and is suitable as a grease base oil. Recognize. Furthermore, it can be seen from Table 2 that the use of ester A as the grease base oil improves the dropping point (heat resistance) and oxidation stability of the grease composition.

In addition to providing an aromatic ester-based grease base oil excellent in viscosity index and low-temperature fluidity, a grease composition using the same has a suitable performance balance and is optimal for grease applications.

Claims (8)

General formula (1)
[Wherein, R ¹ and R ² are the same or different and each represents a linear or branched alkyl group having 4 to 12 carbon atoms. ]
Benzenedicarboxylic acid diester represented by the formula (2), and the two or more benzenedicarboxylic acid diesters include at least ^one of R ¹ and R ² represented by an n-nonyl group Grease base oil containing diester. The ratio of the benzene dicarboxylic acid diester in which at least ^one of R ¹ and R ² is represented by an n-nonyl group is 50% by weight or more based on the total weight of the benzene dicarboxylic acid diester. Grease base oil. The benzene dicarboxylic acid diester in which at least ^one of R ¹ and R ² in the general formula (1) is represented by a branched alkyl group having 9 carbon atoms is included in the two or more kinds of benzene dicarboxylic acid diesters. Or the grease base oil of Claim 2. The benzenedicarboxylic acid diester represented by the general formula (1)
General formula (2)
[Wherein, R ¹ and R ² are the same or different and each represents a linear or branched alkyl group having 4 to 12 carbon atoms. ]
The grease base oil according to claim 1, which is a phthalic acid diester represented by the formula: The grease base oil according to any one of claims 1 to 4, wherein two or more kinds of benzenedicarboxylic acid diesters have a viscosity index of 80 to 130. A grease composition comprising the grease base oil according to any one of claims 1 to 5, a thickener and an antioxidant. The total content of the grease base oil, thickener and antioxidant does not exceed 100% by weight in the grease composition, and 60 to 95% by weight of grease base oil, 2 to 40% by weight of thickener and The grease composition according to claim 6, comprising 0.1 to 10% by weight of an antioxidant. Furthermore, it contains one or more of a metal detergent, an ashless dispersant, an extreme pressure agent, a metal deactivator, a corrosion inhibitor, a hue stabilizer, a rust inhibitor, a thickener, and an oily agent. Or the grease composition of Claim 7.