JP6602876B2 - Grease composition - Google Patents

Description

  The present invention relates to a grease composition. Specifically, the present invention relates to a grease composition that can exhibit good lubricating performance and wear resistance at various temperatures and loads.

  Lubricants generally include base oils and various additives. Base oils include mineral oils obtained from crude oils, chemically synthesized ester oils, fluorine oils, poly-α-olefin oils, and the like. Among these, ester oils are suitably used for jet aircraft, automobile engine oils, greases and the like because of their low pour point, high viscosity index, high flash point, good lubricating performance, biodegradability, and the like.

  It is known that ester oils are used as base oils or additives. For example, monoester obtained from reaction of aliphatic monocarboxylic acid and monool; diester obtained from reaction of aliphatic dibasic acid and monool; ester obtained from reaction of aromatic polycarboxylic acid and monool Polyol polyol obtained from reaction of polyhydric alcohol and aliphatic carboxylic acid; complex ester obtained from reaction of polyhydric alcohol, polybasic acid, aliphatic monocarboxylic acid; polyhydric alcohol, polybasic acid, monool Various esters such as complex esters obtained from the reaction with (Patent Documents 1 to 7) are disclosed.

JP 2002-097482 A JP 2005-154726 A JP 2005-232434 A JP 2005-213377 A JP 2005-232470 A JP-T-2002-530476 JP 2011-89106 A

A grease composition can be obtained by mixing the ester oil as described above with a thickener. In recent years, with the diversification and sophistication of the industrial field, grease compositions are required to have high lubrication performance. Specifically, it is required to develop good friction characteristics (lubricating performance) at various temperatures and load regions. In addition, the grease composition is also required to suppress wear on the sliding surface of an apparatus or the like.
However, in the conventional grease composition, lubrication performance and wear resistance may not be sufficiently exhibited, and further improvement is demanded.

  The problem to be solved by the present invention is to provide a grease composition that can exhibit good friction characteristics (lubricating performance) and wear resistance at various temperatures and loads.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the grease composition contains a specific complex ester, a base oil, and a thickener, so that various temperatures and loads can be obtained. It was found that both good friction characteristics (lubricating performance) and wear resistance can be exhibited.
In addition, the present inventors have determined that the oil-based lubricant composition (lubricating oil) and the grease composition do not necessarily have the same configuration capable of exhibiting a preferable function, and particularly preferable lubricating performance in the grease composition. The present inventors have found a structure that can exhibit wear resistance and have completed the present invention.
Specifically, the present invention has the following configuration.

[1] The composite ester A includes a base ester and a thickener, and the composite ester A includes a trihydric or higher polyhydric alcohol a1, a polyhydric carboxylic acid a2 having 5 or more carbon atoms, and a carbon number of 6 or more. A grease composition comprising an ester condensed with monool a3.
[2] The grease composition according to [1], further including a compound having at least one selected from zinc, molybdenum, and phosphorus.
[3] The grease composition according to [1] or [2], wherein the content of the complex ester A is 0.1 to 15% by mass with respect to the total mass of the grease composition.
[4] The grease composition according to any one of [1] to [3], wherein the content of the complex ester A is 0.1 to 6% by mass with respect to the total mass of the grease composition.
[5] The grease composition according to any one of [1] to [4], wherein the polyvalent carboxylic acid a2 has 12 or more carbon atoms.
[6] The grease composition according to any one of [1] to [5], wherein the polyvalent carboxylic acid a2 has 36 or more carbon atoms.
[7] The grease composition according to any one of [1] to [6], wherein the monool a3 has 8 or more carbon atoms.
[8] The grease composition according to any one of [1] to [7], wherein the monool a3 has an oxyalkylene structure.
[9] The grease composition according to any one of [1] to [8], wherein the monool a3 has an alkyl group having 6 or more carbon atoms.
[10] The grease composition according to any one of [1] to [9], wherein the thickener is at least one selected from metal soaps, metal composite soaps, and urea compounds.
[11] The grease composition according to any one of [1] to [10], wherein the content of the base oil is 60 to 95% by mass with respect to the total mass of the grease composition.
[12] The grease composition according to any one of [1] to [11], wherein the base oil contains at least one selected from mineral oil and poly-α-olefin oil.

  According to the present invention, it is possible to obtain a grease composition that can exhibit good friction characteristics (lubricating performance) and wear resistance at various temperatures and load regions.

  Hereinafter, the present invention will be described in detail. The constituent elements described below may be described based on representative embodiments and specific examples, but the present invention is not limited to such embodiments. In the present specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

  In addition, examples of the substituent in the present specification include an alkyl group (for example, methyl, ethyl, all of which are linear or branched, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, Undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, eicosyl, heneicosyl, docosyl, tricosyl, or tetracosyl); an alkenyl group (eg, propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, , Undecenyl, dodecenyl); cycloalkyl groups (eg cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl); aromatic ring groups (eg phenyl, naphthyl, biphenyl) Preferably a heterocyclic residue containing at least one heteroatom selected from a nitrogen atom, an oxygen atom, and a sulfur atom, such as pyridyl, pyrimidyl, triazinyl, Thienyl, furyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, thiazolyl, imidazolyl, oxazolyl, thiadialyl, oxadiazolyl, quinolyl, isoquinolyl); or a combination thereof. If possible, these substituents may further have one or more substituents. Examples of the substituents include alkoxy groups, alkoxycarbonyl groups, halogen atoms, ether groups, alkylcarbonyl groups, cyano groups. Group, thioether group, sulfoxide group, sulfonyl group, amide group and the like.

(Grease composition)
The present invention relates to a grease composition comprising complex ester A, a base oil and a thickener. The composite ester A includes an ester in which a trihydric or higher polyhydric alcohol a1, a polyhydric carboxylic acid a2 having 5 or more carbon atoms, and a monool a3 having 6 or more carbon atoms are condensed at least.

  The grease composition of the present invention is obtained by mixing a complex ester A containing a specific ester with a base oil and a thickener. For this reason, the grease composition of the present invention has a low coefficient of friction and a reduced amount of wear at various temperatures and load regions. That is, the grease composition of the present invention has good lubricating performance and is excellent in wear resistance.

  The content of the composite ester A is preferably 0.1 to 15% by mass, more preferably 0.1 to 12% by mass, and 0.1 to 6% by mass with respect to the total mass of the grease composition. % Is more preferable, 0.1 to 5% by mass is still more preferable, and 0.5 to 3% by mass is particularly preferable. By setting the content of the composite ester A within the above range, the lubricating performance and wear resistance of the grease composition can be improved more effectively. In addition, the grease composition of the present invention can exhibit excellent lubricating performance and wear resistance even when the content of the complex ester A is small.

  The blending degree of the grease composition of the present invention measured by JIS K 2220.7 method is preferably 85 to 475, more preferably 130 to 430, and particularly preferably 175 to 385. By making the penetration of the grease composition within the above range, the lubricating performance and wear resistance of the grease composition can be more effectively enhanced.

(Composite ester A)
The composite ester A includes an ester in which a trihydric or higher polyhydric alcohol a1, a polyhydric carboxylic acid a2 having 5 or more carbon atoms, and a monool a3 having 6 or more carbon atoms are condensed at least.

<Trivalent or higher polyhydric alcohol a1>
Examples of the trihydric or higher polyhydric alcohol a1 include compounds containing three or more alcoholic hydroxyl groups and / or phenolic hydroxyl groups in the molecule. Among these, the trihydric or higher polyhydric alcohol a1 is preferably a compound containing three or more alcoholic hydroxyl groups, and more preferably a compound having 3 to 6 alcoholic hydroxyl groups.
The trihydric or higher polyhydric alcohol is preferably an alcohol represented by the following general formula (a1-1a).

  In general formula (a1-1a), Z represents an m1-valent linking group, and m1 represents an integer of 3 or more.

The alcohol represented by the general formula (a1-1a) is an m1-valent alcohol.
In general formula (a1-1a), Z is an m1-valent linking group, and in other words, Z means a polyhydric alcohol mother nucleus formed by removing m1 hydroxyl groups from an m1-valent alcohol.

Z is an m1-valent linking group containing at least one trivalent or higher linking group. The trivalent or higher valent linking group is not particularly limited, and preferred examples thereof include a trivalent linking group containing a tertiary carbon atom and a quaternary carbon atom.
The trivalent linking group containing a tertiary carbon atom preferably has the following structure, and R ^c in the following structure represents a hydrogen atom or a substituent. * Represents a binding site with a linking chain.

  A quaternary carbon atom has the following structure:

Z represents an alkylene group, an arylene group and a structure in which a plurality of these are a single bond, or an alkylene group, an arylene group and a plurality of these are a divalent linking group (preferably -O-, -C (=) O-,- OC (=) O -, - S -, - SO 2 -, - C (= O) -, - C (= O) NR b - (R b represents a hydrogen atom, an alkyl group, an aryl group)) or trivalent It is preferably an m1 valent linking group containing a structure linked by the above linking groups and containing at least one trivalent or higher linking group. Z may have other substituents.
Among them, Z is preferably a residue obtained by removing a hydroxyl group from a preferable example of a trihydric or higher polyhydric alcohol described later.

  m1 should just be an integer greater than or equal to 3, Preferably it is 3-6, More preferably, it is 3 or 4.

Specific examples of the trihydric or higher polyhydric alcohol include glycerin, 1,2,3-butanetriol, 1,2,4-butanetriol, 1,2,3-pentanetriol, 1,2,4- Pentanetriol, 2-methyl-1,2,3-propanetriol, 2-methyl-2,3,4-butanetriol, 2-ethyl-1,2,3-butanetriol, 2,3,4-pentanetriol 3-methylpentane-1,3,5-triol, 2,4-dimethyl-2,3,4-pentanetriol, 2,3,4-hexanetriol, 4-propyl-3,4,5-heptanetriol Trivalent alcohols such as 1,3,5-cyclohexanetriol, pentamethylglycerin, trimethylolethane, trimethylolpropane;
Tetrahydric alcohols such as 1,2,3,4-butanetetraol, pentaerythritol, diglycerin, sorbitan, ribose, arabinose, xylose, lyxose, ditrimethylolethane, ditrimethylolpropane;
Pentahydric alcohols such as arabitol, xylitol, glucose, fructose, galactose, mannose, allose, gulose, idose, talose;
Hexavalent alcohols such as dipentaerythritol, sorbitol, galactitol, mannitol, allitol, iditol, taritol, inositol, quercitol;
Mention may be made of octavalent alcohols such as tripentaerythritol.
Among these, trimethylolethane, trimethylolpropane, glycerol, pentaerythritol, ditrimethylolethane, ditrimethylolpropane, dipentaerythritol, and tripentaerythritol are more preferable, and trimethylolpropane, trimethylolethane, ditrimethylolpropane, glycerol, penta Erythritol and dipentaerythritol are particularly preferred.

As the trihydric or higher polyhydric alcohol a1, a compound obtained by adding alkylene oxide to at least one of the hydroxyl groups of the trihydric or higher polyhydric alcohol (compound having an alkyleneoxy structure) can also be preferably used. . As the added alkylene oxide, ethylene oxide, propylene oxide, butylene oxide and a plurality of combinations thereof are preferable, and ethylene oxide and propylene oxide are more preferable. In this case, the trihydric or higher polyhydric alcohol a1 is preferably a compound obtained by adding an independent alkylene oxide to all hydroxyl groups of the trihydric or higher polyhydric alcohol.
The average number of alkylene oxides (oxyalkylene structures) contained in the trihydric or higher polyhydric alcohol a1 is preferably 1 to 200, and more preferably 1 to 100. More preferable addition number of alkylene oxide is 1 to 20 times the average number of hydroxyl groups of polyhydric alcohol a1 having a valence of 3 or more, more preferably 2 to 10 times, particularly preferably. The number is 3 to 7 times.

  The trihydric or higher polyhydric alcohol a1 having an oxyalkylene structure is preferably a compound represented by the following general formula (a1-1b).

In general formula (a1-1b), Z represents an m1-valent linking group, m1 represents an integer of 3 or more, R ¹¹ represents an alkylene group, and n1 represents an integer of 1 to 100.

  Z and m1 in general formula (a1-1b) are synonymous with Z and m1 in general formula a1-1a, respectively. Preferred Z is a residue obtained by removing a hydroxyl group from the preferred examples of the trihydric or higher polyhydric alcohol described above.

R ¹¹ is an alkylene group, preferably an ethylene group, a propylene group or a butylene group, more preferably an ethylene group or a propylene group. A plurality of R ¹¹ may be the same or different.
n1 is preferably an integer of 1 to 100, more preferably 1 to 20, still more preferably 2 to 10, and particularly preferably 3 to 7. A plurality of n1 may be the same or different.

  Specific examples of the trihydric or higher polyhydric alcohol a1 that can be used in the present invention are shown below, but the present invention is not limited thereto.

The compound a1-e has a number average molecular weight (Mn) of 450 and an average value of y ¹¹ + y ¹² + y ¹³ is 7.
The compound a1-f has a number average molecular weight (Mn) of 797, and the average value of y ³¹ + y ³² + y ³³ + y ³⁴ is 15 compounds.

<Polyvalent carboxylic acid a2 having 5 or more carbon atoms>
The polyvalent carboxylic acid a2 is a polyvalent carboxylic acid having 5 or more carbon atoms. In the present specification, the polyvalent carboxylic acid a2 includes a carboxylic acid precursor. That is, the polyvalent carboxylic acid a2 is a compound having two or more carboxyl groups or carboxylic acid precursor structures, preferably 2 to 4 carboxyl groups or carboxylic acid precursor structures, more preferably 2 or 3, More preferably, it is a compound having two. Here, the carboxylic acid precursor structure represents a structure capable of reacting with a trihydric or higher polyhydric alcohol a1 or a monool a3 alcohol to form an ester bond. As the carboxylic acid precursor, a carboxylic acid halide, Mixed anhydride of carboxylic acid ester (preferably methyl ester, ethyl ester), carboxylic acid anhydride, carboxylic acid and other acids (preferably sulfonic acid such as methanesulfonic acid and toluenesulfonic acid, substituted carboxylic acid such as trifluoroacetic acid) A thing can be illustrated preferably. Hereinafter, the carboxylic acid precursor is also included in the detailed description of the polyvalent carboxylic acid a2.

  The carboxyl group in the molecule of the polyvalent carboxylic acid a2 having 5 or more carbon atoms is linked with a chain or cyclic divalent or higher aliphatic hydrocarbon or aromatic hydrocarbon. One or more carbon atoms not adjacent to each other of the carbon atoms of the aliphatic hydrocarbon or aromatic hydrocarbon linking group may be substituted with oxygen atoms. The aliphatic hydrocarbon or aromatic hydrocarbon linking group may have a substituent, and in this case, the substituent is preferably a halogen atom, an alkyl group, or an alkenyl group, and is an alkyl group. Is more preferable. The polyvalent carboxylic acid a2 preferably has a branched alkyl group from the viewpoint of lubricating performance.

  The polyvalent carboxylic acid a2 may have 5 or more carbon atoms, preferably 8 or more, more preferably 12 or more, still more preferably 22 or more, and particularly preferably 26 or more. Preferably, it is more preferably 36 or more. The carbon number of the polyvalent carboxylic acid a2 is preferably 70 or less, more preferably 66 or less, and even more preferably 59 or less. In the present specification, the carbon number of the polyvalent carboxylic acid a2 represents the number of carbon atoms including the carbon atom constituting the carboxyl group. Thus, by making the carbon number of polyvalent carboxylic acid a2 into the said range, the lubrication performance and abrasion resistance of a grease composition can be improved more.

  Examples of the polyvalent carboxylic acid a2 that can be used in the present invention include terephthalic acid, phthalic acid, glutaric acid, alkyl-substituted succinic acid, alkenyl-substituted succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, and dodecanedione. Acid, trimellitic acid, dimer acid (dimer of unsaturated carboxylic acid having 18 carbon atoms), hydrogenated dimer acid, trimer acid (trimer of unsaturated carboxylic acid having 18 carbon atoms), carbon number 22 dimers (for example, erucic acid dimer) of unsaturated carboxylic acid. Among these, dimer acid, hydrogenated dimer acid, trimer acid, and erucic acid dimer are preferably used from the viewpoint of solubility in base oil.

Here, the dimer acid refers to an acid containing an aliphatic or alicyclic dicarboxylic acid as a main component, which is generated by dimerization of an unsaturated fatty acid (usually 18 carbon atoms) by polymerization or Diels-Alder reaction. A trimer having a main component is defined as trimer acid. Here, a main component means the component contained 75 mass% or more. For example, dimer acids often contain several mole% of trimer, monomer, etc. in addition to the main component dimer.
Specific examples of the dimer acid include Tsunodim (registered trademark) 205, 216, 228, and 395 manufactured by Tsukino Food Industry Co., Ltd., and specific examples of the trimer acid include Tsunodim 345 and the like. Other examples of dimer acid or trimer acid include products of Cognis and Unikema.

  Specific examples of the polyvalent carboxylic acid a2 having 5 or more carbon atoms that can be used in the present invention are shown below, but the present invention is not limited thereto.

<Monool a3 having 6 or more carbon atoms>
Monool a3 having 6 or more carbon atoms is represented by R—OH, and R is a monovalent aliphatic, alicyclic or aromatic ring group having 6 or more carbon atoms. One or more carbon atoms not adjacent to each other in R may be substituted with oxygen atoms. R may have 6 or more carbon atoms, more preferably 8 or more. By setting the carbon number of the monool a3 within the above range, the solubility of the composite ester A in the base oil can be improved, and the lubricating performance can be improved. Furthermore, by making the carbon number of the monool a3 within the above range, the monool a3 can be prevented from being volatilized during the condensation reaction of the composite ester A.

The monool a3 having 6 or more carbon atoms is preferably a monool a3 having an aliphatic group having 6 or more carbon atoms. Examples of the aliphatic group include an alkyl group, alkenyl group, alkynyl group, cycloalkyl group, cycloalkenyl group, alkylene group, alkenylene group, alkynylene group, cycloalkylene group, and cycloalkenylene group. Among these, monool a3 is more preferably monool a3 having an alkyl group having 6 or more carbon atoms. Furthermore, the monool a3 having 6 or more carbon atoms preferably has a branched alkyl group. Here, the branched alkyl group is an alkyl group having a branched chain.
Furthermore, the monool a3 preferably has an oxyalkylene structure. When the monool a3 has such a structure, the lubricating performance and wear resistance of the grease composition can be improved. Among these, monool a3 preferably has a branched alkyl group having 6 or more carbon atoms and has an oxyalkylene structure.

  Examples of the monool a3 having 6 or more carbon atoms include 2-ethylhexanol, heptanol, octanol, decanol, dodecanol, hexadecanol, octadecanol, 2-heptylundecanol, eicosadecanol, phytosterol, isoform Examples include stearyl alcohol, stearol, cetol, behenol, and alkylene oxide adducts (compounds having an oxyalkylene structure) of these monools.

The monool a3 used in the present invention preferably has an oxyalkylene structure, and the monool a3 having an oxyalkylene structure is more preferably represented by the following general formula (3).

Here, in the general formula (3), Ra represents an alkyl group which may have ^a substituent, ^a cycloalkyl group which may have a substituent, an alkenyl group which may have a substituent, or a substituent. An aryl group which may have or a heteroaryl group which may have a substituent, and X ^a1 and X ^a2 each independently represent a hydrogen atom, a halogen atom or an alkyl group; Na1 represents an integer of 2 to 4, and na2 represents an integer of 1 to 20. A plurality of X ^a1 may be the same or different, and a plurality of X ^a2 may be the same or different. When na2 is 2 or more, a plurality of —O (CX ^a1 X ^a2 ) _na1 — may be the same or different.

R ^a number of carbon atoms in the alkyl group moiety of the alkyl group which may have a substituent represented by is preferably 1 to 32 is, more preferably from 4 to 32, 6 to 20 Is more preferable. The alkyl group represented by R ^a may be linear or branched, but is preferably branched from the viewpoint of lubrication performance and from the viewpoint of solubility in the base oil. R ^a may be a cycloalkyl group which may have ^a substituent.

The number of carbon atoms of the alkenyl group moiety alkenyl group which may have a substituent represented by R ^a is preferably 2 to 32, more preferably from 4 to 32, 6 to 20 Is more preferable. The alkyl group represented by R ^a may be linear, branched or cyclic.

The number of carbon atoms of the aryl group part of the aryl group or heteroaryl group which may have a substituent represented by ^Ra is preferably 6 to 32, and more preferably 6 to 24. Examples of the aryl group represented by ^Ra include a phenyl group and a naphthyl group, and among them, a phenyl group is particularly preferable. Examples of the heteroaryl group represented by ^Ra include imidazolyl group, pyridyl group, quinolyl group, furyl group, thienyl group, benzoxazolyl group, indolyl group, benzimidazolyl group, benzthiazolyl group, carbazolyl group, azepinyl group Can be illustrated. The hetero atom contained in the heteroaryl group is preferably an oxygen atom, a sulfur atom, or a nitrogen atom, and more preferably an oxygen atom.

Among the above, in general formula (3), R ^a is more preferably an alkyl group which may have ^a substituent. Here, the alkyl group is preferably a branched alkyl group.

In the general formula (3), X ^a1 and X ^a2 each independently represent a hydrogen atom, a halogen atom or an alkyl group, and more preferably a hydrogen atom or an alkyl group.

  In general (3), na1 represents an integer of 2 to 4, more preferably an integer of 2 or 3, and still more preferably 2. Na2 represents an integer of 1 to 20, more preferably an integer of 1 to 15, further preferably an integer of 1 to 10, and particularly preferably an integer of 1 to 5.

  Specific examples of monool a3 that can be used in the present invention are shown below, but the present invention is not limited thereto.

In the compound MA-43, y ¹ is preferably an integer of ¹ to 12, and the compound MA-43 is preferably a compound having an average value of y ¹ of 2 to 7.
In the compound MA-44, y ² is preferably an integer of 1 to 12, and the compound MA-44 is preferably a compound having an average value of y ² of ² to 7.
In the compound MA-42, y ³ is preferably an integer of 1 to 12, and the compound MA-42 is preferably a compound having an average value of y ³ of 2 to 7.

<Other ingredients>
The composite ester A may be obtained by further condensing other components in addition to the a1 to a3 components described above. Other components include dihydric alcohols (preferably aliphatic dihydric alcohols having 2 to 50 carbon atoms), monovalent or polyvalent amines that can be condensed with carboxylic acids to form amide bonds, and monovalent carboxylic acids. Can be mentioned.

(Method for producing complex ester A)
The composite ester A is obtained by at least condensing a trihydric or higher polyhydric alcohol a1, a polyhydric carboxylic acid a2 having 5 or more carbon atoms, and a monool a3 having 6 or more carbon atoms.

  As the charging ratio when performing the condensation reaction, the polyhydric alcohol a1, the polyhydric carboxylic acid a2, and the monool a3 are 2/1 to 1/2 in terms of the molar ratio of carboxyl groups / hydroxyl groups of all carboxylic acids and all alcohols. It is preferably 1.5 / 1 to 1 / 1.5, more preferably 1/1 to 1 / 1.3, and further preferably 1/1 to 1 / 1.2. It is particularly preferred. By setting the charging ratio within the above range, the acid value of the condensate can be lowered, and damage to the member to which the grease composition is applied can be suppressed.

The composite ester A is obtained by subjecting the mixture prepared as described above to a condensation reaction in the presence or absence of a catalyst or a condensing agent.
In the condensation, it is desirable to heat or to make an appropriate amount of a solvent azeotropic with water or a low molecular alcohol. Thereby, the reaction proceeds smoothly without coloring the product. This solvent is preferably a hydrocarbon solvent having a boiling point of 100 to 200 ° C, more preferably a hydrocarbon solvent having a boiling point of 100 to 170 ° C, and most preferably a hydrocarbon solvent having a boiling point of 110 to 160 ° C. Examples of these solvents include toluene, xylene, mesitylene and the like. The addition amount is preferably 1 to 25% by mass, more preferably 2 to 20% by mass, particularly preferably 3 to 15% by mass, and also preferably 5 to 12% by mass with respect to the total amount of raw materials. By setting the addition amount within the above range, the condensation reaction can be more smoothly advanced.

  Although the reaction is accelerated by using the catalyst, it is also desirable not to use it because the post-treatment of removing the catalyst is complicated and causes coloring of the product. However, when used, normal conditions and procedures are used with normal catalysts. In this regard, reference can be made to Japanese Patent Publication Nos. 2001-501989, 2001-500499, 2001-507334, and 2002-509563.

  After completion of the preparation, the reaction is carried out at a liquid temperature of 120 to 250 ° C, preferably 130 to 230 ° C, more preferably 150 to 230 ° C, and particularly preferably 170 to 230 ° C. As a result, a solvent containing water or a low molecular alcohol is azeotroped, cooled at the cooling site, and separated into a liquid. This water may be removed. After reacting at a low temperature, the reaction may be performed at a higher temperature.

  As for the reaction time, since the theoretically generated water amount is calculated from the number of moles charged, it is preferable to carry out the reaction until the water amount is obtained, but it is difficult to complete the reaction completely. Even when the reaction is terminated when the theoretical water generation amount is 60 to 90%, the lubricating performance and wear resistance of the obtained grease composition containing the composite ester A are good. The reaction time is 1 to 24 hours, preferably 3 to 18 hours, more preferably 5 to 18 hours, and most preferably 6 to 15 hours.

  After completion of the reaction and the treatment after the reaction, it is preferable to perform filtration to remove dust and the like. When the composite ester A becomes a solid, it can be melted and taken out or taken out as a powder by reprecipitation.

(Physical properties of composite ester A)
The composite ester A is a product obtained by randomly condensing at least a trihydric or higher polyhydric alcohol a1, a polyhydric carboxylic acid a2 having 5 or more carbon atoms, and a monool a3 having 6 or more carbon atoms. The ester A contains an ester obtained by condensing at least the components a1, a2, and a3.

  The complex ester A may contain an unreacted a3 component. The content of the unreacted a3 component with respect to the total amount of the complex ester A is preferably 10% or less, more preferably 6% or less, and particularly preferably 4% or less. The content of the unreacted a3 component can be calculated using the area ratio of the molecular weight peak corresponding to a3 in GPC measurement. The GPC measurement conditions may be those described later.

The kinematic viscosity at 40 ° C. of the composite ester A is preferably 50 to 2000 mm ² / s. The kinematic viscosity at 40 ° C. of the composite ester A is preferably 50 mm ² / s or more, more preferably 70 mm ² / s or more, and further preferably 100 mm ² / s or more. The kinematic viscosity at 40 ° C. of the composite ester A is preferably 2000 mm ² / s or less, more preferably 1500 mm ² / s or less, and still more preferably 1000 mm ² / s or less. By setting the kinematic viscosity of the composite ester A within the above range, the friction coefficient of the grease composition can be kept low, thereby improving the lubrication performance. In this specification, the kinematic viscosity at 40 ° C. of the composite ester A is specifically a value measured in a constant temperature water bath at 40.0 ° C. using an Ubbelohde viscometer.

The molecular weight of the complex ester A is preferably a weight average molecular weight in terms of standard polystyrene using gel permeation chromatography (GPC), preferably from 1,000 to 100,000, more preferably from 2,000 to 20,000, and even more preferably from 3,000 to 10,000. By setting the molecular weight within the above range, the lubricating performance of the grease composition can be improved. The value measured on condition of the following is employ | adopted for the weight average molecular weight of polystyrene conversion of the composite ester A in this specification.
“HLC-8220GPC (manufactured by Tosoh Corporation)” is used as the apparatus. Columns are “TSKgel, SuperHZM-H (manufactured by Tosoh Corporation, 4.6 mm ID × 15 cm)”, “TSKgel, SuperHZ4000 (manufactured by Tosoh Corporation, 4.6 mmID × 15 cm)”, TSKgel, SuperHZ2000 (Tosoh Corporation) 3 ", 4.6 mm ID x 15 cm)" is used.

The following conditions are adopted as GPC conditions.
・ Eluent THF (tetrahydrofuran)
・ Flow rate 0.35ml / min
・ Measurement temperature: 40 ° C. (column, inlet, RI (Refractive Index))
・ Analysis time 20 minutes ・ Sample concentration 0.1%
・ Sample injection volume 10μl

  In the present invention, an unreacted COOH group may remain in the composite ester A, or an OH group may exist. When the OH group and the COOH group remain, the hydroxyl value and the acid value are reduced. Depending on the application, it may not be preferable. In such a case, OH group and COOH group can be eliminated by separate acylation and / or esterification treatment, and the hydroxyl value and acid value can be reduced.

The ratio of the unreacted OH group of the complex ester A can be determined by measuring ¹³ C-NMR (Nuclear Magnetic Resonance). The residual ratio of OH groups in the composite ester A is preferably 0 to 40%, more preferably 0 to 35%, and further preferably 0 to 30%.

  The acid value of complex ester A (mg number of KOH required to neutralize 1 g of sample) is preferably 0 to 50 mg KOH, more preferably 0 to 30 mg KOH, and 0 to 20 mg KOH. More preferably. In the present specification, specifically, the acid value of the complex ester A (the number of mg of KOH required to neutralize 1 g of the sample) can be a value measured according to the JIS K 2501 method.

(Base oil)
The grease composition of the present invention contains a base oil.
Base oils include mineral oils, fat compounds, polyolefin oils (eg, poly-α-olefin oils), silicone oils, ether oils (eg, perfluoropolyether oils, diphenyl ether derivatives), and ester oils (eg, aromatic ester oils, Monovalent fatty acid ester, divalent fatty acid diester, polyol ester lubricating oil). Among these, the base oil is preferably at least one selected from mineral oil, polyolefin oil and ester oil, and particularly preferably contains at least one selected from mineral oil and poly-α-olefin oil.

In the present invention, the type of mineral oil is not particularly defined, but preferably, the lubricating oil fraction obtained by atmospheric distillation and vacuum distillation of crude oil is subjected to solvent removal, solvent extraction, hydrocracking. And mineral oils such as paraffinic or naphthenic oils obtained by applying a suitable combination of one or more purification means such as solvent dewaxing, catalytic dewaxing, hydrorefining, sulfuric acid washing, and clay treatment. .
Preferred examples of the poly-α-olefin oil include polybutene, polyhexene, polyoctene, and polydecene.
Preferred examples of the ester oil include bis (2-ethylhexyl) sebacate and trimethylolpropane trifatty acid ester.

Kinematic viscosity at 40 ° C. of the base oil is preferably 1 to 500 mm ² / s, more preferably from 10 to 200 mm ² / s, more preferably 20 to 100 mm ² / s. By setting the kinematic viscosity of the base oil at 40 ° C. within the above range, the lubricating performance and wear resistance are further improved.

The viscosity index of the base oil is preferably 90 or more, more preferably 105 or more, and even more preferably 110 or more. Further, the viscosity index of the base oil is preferably 160 or less. By setting the viscosity index within the above range, viscosity-temperature characteristics, thermal / oxidative stability, and volatilization prevention properties are improved, and wear resistance is further improved.
In addition, the viscosity index as used in the field of this invention means the viscosity index measured based on JISK2283-1993.

  The content of the base oil is preferably 60 to 95% by mass and more preferably 70 to 90% by mass with respect to the total mass of the grease composition. By setting the content of the base oil within the above range, the lubricating performance and the wear resistance can be further improved.

(Thickener)
The grease composition of the present invention includes a thickener.
Examples of the thickener include soap-based thickeners, urea-based thickeners, organic thickeners, bentonite, and silica gel. Among them, it is preferable to use a soap-based thickener and a urea-based thickener, and it is more preferable that the thickener is at least one selected from a metal soap, a metal composite soap, and a urea compound.

<Soap thickener>
Examples of the soap thickener include metal soaps and metal composite soaps obtained by a saponification reaction between a fatty acid and an alkali metal hydroxide or alkaline earth metal. As the fatty acid, lauric acid, myristic acid, palmitic acid, stearic acid, 12-hydroxystearic acid, isostearic acid, oleic acid, linoleic acid, linolenic acid, eicosanoic acid and the like are preferable. Examples of the alkali metal in the alkali metal hydroxide include lithium, sodium, and potassium, and examples of the alkaline earth metal include calcium and magnesium. Among these, a lithium soap thickener is preferably used.
In addition, the metal soap has a single fatty acid part, and the metal composite soap has two or more fatty acid parts.

A complex soap thickener is also preferably used as the soap thickener. A composite soap is a soap saponified by combining different fatty acids. The composite soap is preferably a metal composite soap containing the above-described metal soap and a metal salt of the second fatty acid in a composite manner.
As the composite soap thickener, a lithium composite soap thickener is preferably used. Here, the lithium composite soap contains a metal salt of a second acid in addition to a lithium salt of a fatty acid. Specifically, what mix | blended 12-hydroxy lithium stearate and azelaic acid lithium etc. are mentioned. As another composite soap thickener, it is also preferable to use an aluminum composite soap thickener, and examples of the aluminum composite soap include aluminum stearate benzoate.

<Urea-based thickener>
The urea-based thickener is a thickener containing a urea bond, and is preferably a urea compound. The urea compound may be a monourea compound having one urea bond or a polyurea compound having a plurality of urea bonds. As the urea compound, it is preferable to use a polyurea compound, and it is particularly preferable to use a diurea compound having two urea bonds.

  The urea compound can be obtained, for example, by a reaction between an isocyanate and an amine. For example, a monourea compound can be obtained by reaction of monoisocyanate and monoamine. Diurea compounds can be obtained by the reaction of diisocyanates and monoamines. A polyurea compound having three or more urea bonds can be obtained by reaction of diisocyanate, diamine and monoamine.

Examples of the diisocyanate include diphenylmethane diisocyanate, tolylene diisocyanate, bitolylene diisocyanate, meta (m) -xylene diisocyanate, phenylene diisocyanate, diphenyl diisocyanate, and phenyl diisocyanate. Aliphatic diisocyanates are mentioned.
As monoamines, aromatic amines such as aniline, para (p) -chloroaniline, benzylamine, meta (m) -xylidine, para (p) -toluidine, ortho (o) -toluidine, octylamine, dodecylamine, Examples include aliphatic amines such as hexadecylamine, octadecylamine, oleylamine, cyclohexylamine, and furfurylamine.

<Organic thickener>
Examples of organic thickeners include terephthalate metal salts. Examples of the terephthalamate metal salt include sodium terephthalate and lithium terephthalate, and sodium terephthalate is preferably used.

  As the thickener, two or more of the above-described thickeners may be used in combination. The total content of the thickener is preferably 1 to 30% by mass, more preferably 3 to 25% by mass, and 5 to 20% by mass with respect to the total mass of the grease composition. Further preferred.

(Other additives)
The grease composition of the present invention preferably further contains a compound having at least one selected from zinc, molybdenum and phosphorus. Especially, it is more preferable that a grease composition contains the compound which has at least 1 type chosen from zinc and molybdenum. Such compounds have functions such as friction modifiers, antiwear agents, and antioxidants. The compound containing at least one of zinc, molybdenum, and phosphorus as a constituent element means a compound that may contain zinc, molybdenum, and phosphorus in any state. Specific examples include compounds containing zinc, molybdenum, and phosphorus as simple substances (oxidation number 0), ions, complexes, and the like. Examples of such compounds include organic molybdenum compounds, inorganic molybdenum compounds, organic zinc compounds, and (phosphorous) phosphoric acid derivatives. Of these, organic molybdenum compounds and organic zinc compounds are preferred.

  Only one compound containing at least one selected from zinc, molybdenum and phosphorus as a constituent element may be added to the grease composition of the present invention, and two or more compounds may be added to the grease composition of the present invention. Also good. When using in combination of two or more compounds containing at least one selected from zinc, molybdenum, and phosphorus as constituent elements, two of organic molybdenum compounds, inorganic molybdenum compounds, organic zinc compounds, and (sub) phosphoric acid derivatives It is preferable to combine the above, and it is more preferable to combine an organic molybdenum compound and an organic zinc compound.

  Hereinafter, preferred embodiments of the organic molybdenum compound, the inorganic molybdenum compound, the organic zinc compound, and the (phosphorous) derivative will be described.

Examples of the organic molybdenum compound used as an additive in the grease composition include organic molybdenum compounds containing phosphorus such as molybdenum dithiophosphate (sometimes referred to as MoDTP). As another organic molybdenum compound, an organic molybdenum compound containing sulfur such as molybdenum dithiocarbamate (sometimes referred to as MoDTC) can be given. Examples of the organic molybdenum compound containing sulfur include sulfurized oxymolybdenum-N, N-di-octyldithiocarbamate (C ₈ -Mo (DTC)), sulfurized oxymolybdenum-N, N-di-tridecyldithiocarbamate ( C ₁₆ -Mo (DTC)) and the like are preferable.

Examples of other sulfur-containing organic molybdenum compounds include complexes of inorganic molybdenum compounds and sulfur-containing organic compounds. Examples of the inorganic molybdenum compound used in the organic molybdenum compound that is a complex of an inorganic molybdenum compound and a sulfur-containing organic compound include molybdenum oxide such as molybdenum dioxide and molybdenum trioxide, orthomolybdic acid, paramolybdic acid, and (poly) sulfuric acid. Molybdic acid such as molybdic acid, metal salts of molybdic acid, molybdate such as ammonium salt, molybdenum disulfide, molybdenum trisulfide, molybdenum pentasulfide, molybdenum sulfide such as polysulfide molybdenum, molybdenum sulfide, molybdenum sulfide Examples thereof include metal salts or amine salts, and molybdenum halides such as molybdenum chloride. Examples of the sulfur-containing organic compound used in the organic molybdenum compound, which is a complex of an inorganic molybdenum compound and a sulfur-containing organic compound, include alkyl (thio) xanthate, thiadiazole, mercaptothiadiazole, thiocarbonate, tetrahydrocarbyl thiuram disulfide. Bis (di (thio) hydrocarbyl dithiophosphonate) disulfide, organic (poly) sulfide, sulfurized ester and the like.
Examples of other organic molybdenum compounds containing sulfur include complexes of sulfur-containing molybdenum compounds such as molybdenum sulfide and sulfurized molybdenum acid with alkenyl succinimides.

  As the organic molybdenum compound, an organic molybdenum compound that does not contain phosphorus or sulfur as a constituent element can be used. Specific examples of organic molybdenum compounds that do not contain phosphorus or sulfur as constituent elements include molybdenum-amine complexes, molybdenum-succinimide complexes, molybdenum salts of organic acids, and molybdenum salts of alcohols. Amine complexes, molybdenum salts of organic acids and molybdenum salts of alcohols are preferred.

  Examples of the inorganic molybdenum compound used as an additive in the grease composition include those similar to those exemplified as the inorganic molybdenum compound used in the organic molybdenum compound that is a complex of the inorganic molybdenum compound and the sulfur-containing organic compound. it can.

  As the organic zinc compound used as an additive in the grease composition, zinc dithiophosphate (ZDTP) zinc diphosphate (ZDP) represented by the following formula is preferable.

In the above formula, Q ¹ , Q ² , Q ³ and Q ⁴ may be the same or different and are each independently isopropyl, butyl, isobutyl, pentyl, isopentyl, neopentyl, hexyl, heptyl. Represents an alkyl group having 8 to 20 carbon atoms such as a group, an octyl group, a 2-ethylhexyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, an isotridecyl group, a misty group, a palmityl group, and a stearyl group.

Specific examples of zinc dithiophosphate (ZDTP) represented by the above formula include zinc n-butyl-n-pentyldithiophosphate (C ₄ / C ₅ ZnDTP) and zinc di-2-ethylhexyldithiophosphate (C ₈ ZnDTP). Alternatively, zinc isopropyl-1-ethylbutyldithiophosphate (C ₃ / C ₆ ZnDTP) is preferable.

When the organic molybdenum compound is used in the grease composition of the present invention, the organic molybdenum compound is preferably contained in an amount of 10 to 5000 mg / L as the molybdenum content with respect to the total mass of the grease composition, and is preferably 50 to 2000 mg / L. L is more preferable, and 100 to 1000 mg / L is more preferable.
Moreover, when using an organic zinc compound, it is preferable that 50-10000 mg / L of zinc content is contained as a zinc content with respect to the grease composition total mass, and it is contained 100-5000 mg / L. More preferably, it is more preferably 200 to 1500 mg / L.
By setting the content of the organometallic compound such as the organomolybdenum compound and the organozinc compound in the grease composition within the above range, the stability of the grease composition can be enhanced. Further, it is possible to improve lubrication characteristics under severe conditions such as high temperature and / or high pressure, and to further exhibit wear resistance.

  Examples of the (sub) phosphoric acid derivative include, in addition to the above-mentioned zinc dithiophosphate (ZDTP) and zinc diphosphate (ZDP), phosphites, phosphate esters, tricresyl phosphate and other aromatic phosphate esters, phosphorus Aliphatic phosphate esters such as trialkyl acids can be exemplified as preferred examples. Of these, aromatic phosphate esters such as tricresyl phosphate and aliphatic phosphate esters such as trialkyl phosphate are more preferable.

The grease composition of the present invention may contain various additives in addition to the above components.
The grease composition of the present invention has, for example, an organic sulfur compound (polysulfides are preferred, dialkyl polysulfide is more preferred), a viscosity index improver (preferably polyalkyl (meth) acrylate, alkyl (meth) acrylate-polar group). (Meth) acrylate copolymers, butadiene, olefin or alkylated styrene polymers and copolymers), antioxidants (preferably hindered phenol compounds, sulfurized alkylphenol compounds, aromatic amine compounds, low sulfur peroxide decomposers, oils) Soluble copper compounds), detergents (sulfate, phenate, carboxylate, phosphate and salicylate alkali metal or alkaline earth metal salts, (boric acid modified) succinimides, succinates), dispersants (preferably phenates, Sulfonates, sulfurized phenates, salicylates, naphthenates, stearates, carbamates, thiocarbamates, phosphorus derivatives, succinic acid derivatives (eg long chain substituted alkenyl succinic acid derivatives, succinimide derivatives, hydrocarbyl substituted succinic acid compounds, succinic acid esters, succinic acid Esteramides), Mannich bases), pour point depressants (preferably polymethacrylates, polyacrylates, polyarylamides, condensation products of haloparaffin waxes and aromatic compounds, vinyl carboxylate polymers and dialkyl fumarate, vinyl esters of fatty acids and Terpolymers of allyl vinyl ether), corrosion inhibitors (preferably thiadiazole), seal compatibilizers (preferably organic phosphates, aromatic esters, aromatic hydrocarbons, esters ( For example, butylbenzyl phthalate), polybutenyl succinic anhydride), antifoaming agent (preferably polydimethylsilicone), rust inhibitor, friction modifier, and antiwear agent may be used. it can.
By adding such an additive, it is possible to enhance functions such as wear resistance. For the additives that can be used in the present invention, the description in paragraphs 0098 to 0165 of JP2011-89106A can be referred to.

  The grease composition can also include a solid lubricant as an additive. Examples of the solid lubricant include polytetrafluoroethylene, boron nitride, fullerene, graphite, fluorinated graphite, melamine cyanurate, molybdenum disulfide, antimony sulfide, and alkali (earth) metal borate.

  The grease composition can also contain a wax as an additive. Examples of the wax include natural waxes, mineral oil-based and synthetic waxes. Specific examples include montan wax, carnauba wax, amide compounds of higher fatty acids, paraffin wax, microcrystalline wax, polyethylene wax, polyolefin wax, ester wax and the like.

  Other additives include metal deactivators. Examples of the metal deactivator include benzotriazole, benzimidazole, thiadiazole and the like.

(Grease composition production method)
The grease composition of the present invention is preferably prepared by synthesizing a thickener in a base oil or a liquid lubricating oil composition containing a base oil and various additives. The complex ester A may be contained in the liquid lubricating oil composition or may be mixed after the thickener is first synthesized in the base oil to form a grease. It is preferable to mix the composition after synthesizing the lubricant to make it grease.
The grease composition of the present invention is preferably produced through a process selected from dehydration, heating, cooling, milling and defoaming.

(Use)
The grease composition of the present invention can be used for machines, bearings, gears and the like. Specifically, rolling bearings used in general-purpose motors such as automotive bearings, home appliances, OA (Office Automation) equipment, industrial machinery, steel, bearings in industrial machinery equipment, various known ball bearings and roller bearings, machine tools It can be suitably used for all grease lubrication locations such as ball screws, linear guides, various sliding parts of construction machines, and gears. The amount of grease composition enclosed at these locations can be changed as appropriate according to the type and dimensions of the locations.

  Hereinafter, the features of the present invention will be described more specifically with reference to Examples and Comparative Examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

(Preparation of base grease)
Base grease was prepared by the following method.

<Base grease G1>
A base grease G1 was prepared by synthesizing lithium soap (thickener) of 12-hydroxystearic acid in mineral oil (kinematic viscosity at 40 ° C .: 68 mm ² / s) to 10% by mass.

<Base grease G2>
Base grease prepared by synthesizing a lithium composite soap (thickener) of azelaic acid and 12-hydroxystearic acid in poly-α-olefin oil (40 ° C. viscosity: 46 mm ² / s) to 15% by mass. G2 was prepared.

<Base grease G3>
Diphenylmethane diisocyanate and octylamine were reacted in poly-α-olefin oil (40 ° C. viscosity: 46 mm ² / s) to synthesize a diurea thickener to a content of 15% by mass to prepare a base grease G3.

<Base grease G4>
Base grease G4 was prepared by reacting diphenylmethane diisocyanate with p-toluidine in an ester oil (40 ° C. viscosity: 32 mm ² / s) to synthesize a diurea thickener to a content of 15% by mass.

(Synthesis of complex esters)
Composite esters A-1 to A-5 were synthesized by the following method.

<Synthesis of Complex Ester A-1>
Trimethylolpropane (manufactured by Wako Pure Chemical Industries) as the polyhydric alcohol a1, sebacic acid as the polycarboxylic acid a2, and 2-ethylhexanol (manufactured by Wako Pure Chemical Industries) as the monool a3 have a molar ratio of 1 / 2.56 / The reaction vessel equipped with a Dean-Stark dewatering device was charged so as to be 3. This mixture was reacted under a nitrogen stream of 0.3 L / min at 190 ° C. for 5 hours and further at 220 ° C. for 4 hours. Water generated during the reaction was removed. The reaction product was allowed to cool to room temperature to obtain a yellow transparent liquid compound ester A-1.

<Synthesis of Complex Esters A-2 to A-5>
Except having decided to use the component a1-a3 shown in Table 1, the composite ester A-2 to A-5 of this invention was obtained using the same method as the synthesis | combination of composite ester A-1.

Each component in Table 1 is as follows.
TMP: Trimethylolpropane (Wako Pure Chemical Industries)
EO-TMP: Ethylene oxide modified trimethylolpropane number average molecular weight (Mn) 450 (manufactured by Aldrich)
SA: Sebacic acid (manufactured by Wako Pure Chemical Industries, Ltd.)
DA: Dimer acid (Tsunodim 395 manufactured by Tsukino Foods, Inc., C36 dicarboxylic acid content 95%)
ED: erucic acid dimer (manufactured by Croda, Prepol 1004)
DDSA: Dodecenyl succinic anhydride (DDSA manufactured by Shin Nippon Chemical Co., Ltd.)
EH: 2-ethylhexanol (manufactured by Wako Pure Chemical Industries, Ltd.)
EHO: 2- (2-ethylhexyloxy) ethanol (manufactured by Wako Pure Chemical Industries, Ltd.)
EHO2: 2- (2-ethylhexyloxy) ethoxyethanol (manufactured by Wako Pure Chemical Industries, Ltd.)

<Synthesis of Comparative Complex Esters X-1 to X-3>
Except having used the component shown in Table 2, and having changed preparation ratio as Table 2, the composite ester X-1 to X-3 of this invention was obtained using the same method as the synthesis | combination of composite ester A-1. .

Each component in Table 2 is as follows.
PE: Pentaerythritol (Wako Pure Chemical Industries, Ltd.)
SU: Succinic anhydride TAGE: Triethylene glycol monoethyl ether BU: 1-butanol

  Further, bis (2-ethylhexyl) sebacate (manufactured by Wako Pure Chemical Industries, Ltd.) was prepared as the comparative ester X-4.

(Preparation of grease composition)
Compound esters and the like were added to the base grease so as to have the compositions shown in Tables 3 to 7, and grease compositions of Examples and Comparative Examples were prepared.

(Evaluation methods)
<Friction coefficient>
About the grease composition of each Example and the comparative example, the friction coefficient was measured using the vibration-type friction-wear tester (The product made by Optimol Instruments Prueftechnik GmbH, SRV 4). The measurement conditions were the following (Condition 1) and (Condition 2) for a 1 hour frictional wear test, and the coefficient of friction was measured after 30 minutes.
(Condition 1) Temperature 80 ° C., frequency 50 Hz, load 200 N
(Condition 2) Temperature 120 ° C., frequency 50 Hz, load 400 N
A SUJ-2 ball having a diameter of 10 mm was used for the upper test piece of the frictional wear test, and a SUJ-2 disk having a diameter of 24 mm was used for the lower test piece. The observed coefficient of friction was evaluated according to the following criteria.
In Table 3, other evaluation results were normalized by setting the friction coefficient of Condition 2 of Comparative Example 1 to 100%, and evaluated as follows. In Tables 4 to 7, other evaluation results were normalized by setting the friction coefficient of the condition 2 of the comparative example listed in each table to 100%, and evaluated as follows.
A smaller value means a smaller coefficient of friction and better lubrication characteristics. The following evaluation criteria a, b, and c were judged to have good lubrication characteristics because the friction coefficient was greatly reduced. In the tests of conditions 1 and 2, an evaluation of c or higher was regarded as a pass evaluation.
a: Less than 40% b: 40% or more and less than 60% c: 60% or more and less than 80% d: 80% or more and less than 90% e: 100% or more

<Abrasion resistance>
About the grease composition of each Example and the comparative example, the wear scar diameter was measured using the four-ball test method of ASTM D4172 method. Measurement conditions were the following (Condition 1) and (Condition 2) for 1 hour test, and the average of the wear scar diameters of the three lower test balls was defined as the wear scar diameter.
(Condition 1) Temperature 75 ° C, rotation speed 1200rpm, load 392N
(Condition 2) Temperature 120 ° C., rotation speed 1200 rpm, load 500 N
In Table 3, other evaluation results were normalized by setting the wear scar diameter of Condition 2 of Comparative Example 1 to 100%, and evaluated as follows. In Tables 4 to 7, other evaluation results were normalized by setting the friction coefficient of the condition 2 of the comparative example listed in each table to 100%, and evaluated as follows.
Smaller values mean less wear and better wear resistance. In the following evaluation criteria, a, b, and c were judged to have good wear resistance because the wear scar diameter was greatly reduced. In the tests of conditions 1 and 2, an evaluation of c or higher was regarded as a pass evaluation.
a: Less than 40% b: 40% or more and less than 60% c: 60% or more and less than 80% d: 80% or more and less than 90% e: 100% or more

  Compared with the comparative example, it can be seen that in the example, the friction coefficient is small, the lubrication characteristics are good, and the wear resistance is good. As can be seen from Tables 3 to 7, in the present invention, the lubricating performance and the wear resistance are improved by containing the specific composite ester A.

Claims (12)

Containing complex ester A, base oil and thickener,
The complex ester A is a trivalent or higher-valent alcohols a1, and the number of carbon atoms 5 or higher polycarboxylic acid a2, and a monool a3 having a carbon number of 6 or more, viewed contains at least fused ester,
The base oil is at least one selected from mineral oil, poly-α-olefin oil and ester oil,
The thickening agent is a grease composition which is at least one selected from metal soaps, metal composite soaps, and urea compounds .   The grease composition according to claim 1, further comprising a compound having at least one selected from zinc, molybdenum, and phosphorus.   The grease composition according to claim 1 or 2, wherein the content of the complex ester A is 0.1 to 15% by mass with respect to the total mass of the grease composition.   The grease composition according to any one of claims 1 to 3, wherein a content of the complex ester A is 0.1 to 6% by mass with respect to a total mass of the grease composition.   The grease composition according to claim 1, wherein the polyvalent carboxylic acid a2 has 12 or more carbon atoms.   The grease composition according to any one of claims 1 to 5, wherein the polyvalent carboxylic acid a2 has 36 or more carbon atoms.   The grease composition according to any one of claims 1 to 6, wherein the monool a3 has 8 or more carbon atoms.   The grease composition according to any one of claims 1 to 7, wherein the monool a3 has an oxyalkylene structure.   The grease composition according to claim 1, wherein the monool a3 has an alkyl group having 6 or more carbon atoms. The grease composition according to any one of claims 1 to 9 , wherein a content of the base oil is 60 to 95 mass% with respect to a total mass of the grease composition. The grease composition according to any one of claims 1 to 10 , wherein the base oil contains at least one selected from mineral oil and poly-α-olefin oil.   The content of the complex ester A is 0.1 to 6% by mass with respect to the total mass of the grease composition,
  The content of the base oil is 70 to 90% by mass with respect to the total mass of the grease composition,
  The grease composition according to any one of claims 1 to 11, wherein a content of the thickener is 5 to 20% by mass with respect to a total mass of the grease composition.