JP2023158326A - grease composition - Google Patents

Abstract

To provide a grease composition excellent in load resistance and abrasion resistance.SOLUTION: The grease composition comprises base oil, a thickener, i.e., barium complex soap, and an organomolybdenum compound, with the content of the organomolybdenum compound being 0.25 to 10 mass% in terms of molybdenum. In the grease composition, the content of the organomolybdenum compound is preferably 0.6 to 5 mass% in terms of molybdenum, the content of the barium complex soap is preferably 15 to 45 mass%, the content of the barium complex soap is preferably 25 to 40 mass%, the kinetic viscosity of the base oil is preferably 15 to 100 mm2/s at 40°C, the fusion load measured according to ASTM D2596 is preferably 3900 N or greater, and the wear mark diameter measured according to ASTM D2266 is preferably 0.45 mm or smaller.SELECTED DRAWING: Figure 1

Description

The present invention relates to grease compositions.

Grease compositions are used as lubricants in various fields such as industrial machinery, transportation machinery, and general machinery. In particular, in applications where heavy loads are applied, such as reduction gear gears, ball screws, and bearings, a grease composition with excellent load resistance is required.

Patent Document 1 describes a grease composition for constant velocity joints containing a base oil, a thickening agent, a detergent-dispersing agent, a sulfur-phosphorus extreme pressure agent, an organic molybdenum compound, and a lignin compound, which improves load carrying capacity and reduces the coefficient of friction. It has been disclosed that it is highly effective. On the other hand, it is desirable that a grease composition used for lubricated locations subject to heavy loads not only have high load-bearing properties but also high wear resistance. However, it is generally difficult to achieve both load carrying capacity and wear resistance, and there is still a need for a grease composition that is sufficiently excellent in both of these properties.

Japanese Patent Application Publication No. 2014-189765

The present invention provides a grease composition that has excellent load carrying capacity and wear resistance.

The gist of the present invention is as follows.
[1] A grease composition containing a base oil, a thickener that is a barium complex soap, and an organic molybdenum compound, wherein the content of the organic molybdenum compound is 0.25 to 10% by mass in terms of molybdenum. .
[2] The grease composition according to [1], wherein the content of the organic molybdenum compound is 0.6 to 5% by mass in terms of molybdenum.
[3] The grease composition according to [1] or [2], wherein the content of the barium composite soap is 15 to 45% by mass.
[4] The grease composition according to any one of [1] to [3], wherein the base oil has a kinematic viscosity of 15 to 100 mm ² /s at 40°C.
[5] The grease composition according to any one of [1] to [4], wherein the fusion load measured according to ASTM D2596 is 3900 N or more, and the wear scar diameter measured according to ASTM D2266 is 0.45 mm or less.

According to the present invention, it is possible to provide a grease composition with excellent load-bearing properties and wear resistance.

1 is a semi-logarithmic plot showing the relationship between the molybdenum equivalent content of an organic molybdenum compound and the fusion load of a grease composition in Examples and Comparative Examples.

The grease composition of the present invention includes a base oil, a thickener that is a barium complex soap, and an organic molybdenum compound. The content of the organic molybdenum compound is 0.25 to 10% by mass in terms of molybdenum. Hereinafter, each component of the grease composition of the present invention will be explained in detail.

[Base oil]
The type of base oil contained in the grease composition of the present invention is not particularly limited, and examples include synthetic oil and mineral oil. Synthetic oils and mineral oils may be used alone or in combination.

Examples of the synthetic oil include hydrocarbon oils such as polyα-olefin, ethylene-α-olefin copolymer, polybutene (polyisobutylene), alkylbenzene, and alkylnaphthalene; diesters (esters of dicarboxylic acids and monoalcohols); polyols; Examples include, but are not limited to, ester oils such as esters and aromatic esters; ether oils such as alkyldiphenyl ethers; and the like. These synthetic oils may be used alone or in combination of two or more.

Among them, hydrocarbon oils are preferred, and polyα-olefins are more preferred. Here, the poly-α-olefin refers to one in which at least one α-olefin is multimerized (typically trimerized to octamerized). Further, an α-olefin refers to a straight chain alkene having three or more carbon atoms and a carbon-carbon double bond at the α position. As the α-olefin, those having 3 to 30 carbon atoms, preferably 4 to 20 carbon atoms, more preferably 6 to 16 carbon atoms are used, but are not limited thereto. Examples of α-olefins include, but are not limited to, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, and the like.

The kinematic viscosity of the base oil contained in the grease composition of the present invention is not particularly limited, but is preferably 5 to 200 mm ² /s at 40°C, preferably 15 to 100 mm ² /s at 40°C, More preferably, it is 20 to 50 mm ² /s at 40°C. When the kinematic viscosity of the base oil is within an appropriate range, it is possible to achieve higher levels of both load carrying capacity and wear resistance.

[Thickener]
The grease composition of the present invention includes a thickener that is a barium complex soap. The grease composition of the present invention can achieve both load-bearing properties and wear resistance by containing barium composite soap as a thickener together with a specific amount of an organic molybdenum compound. This effect is more remarkable than when other thickeners are selected as the thickener used together with the organic molybdenum compound.

Examples of barium complex soap include fatty acids such as stearic acid, oleic acid, and palmitic acid; hydroxy fatty acids with 12 to 24 carbon atoms having one or more hydroxyl groups in the molecule; aromatic carboxylic acids; Examples include those obtained by reacting at least two compounds selected from the group consisting of aliphatic dicarboxylic acids; and their esters or amides (especially carboxylic acid monoamides) with barium hydroxide. but not limited to. Note that the reaction may be performed in base oil. At this time, the at least two types of compounds may be reacted with barium hydroxide simultaneously, or one type at a time may be reacted with barium hydroxide. Alternatively, a plurality of barium soaps may be separately added to the base oil to form a barium composite soap in the base oil.

Examples of the hydroxy fatty acid having 12 to 24 carbon atoms include, but are not limited to, 12-hydroxystearic acid, 12-hydroxylauric acid, 16-hydroxypalmitic acid, and the like. Among these, 12-hydroxystearic acid is preferred. Examples of the aromatic carboxylic acids include, but are not limited to, benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, salicylic acid, and p-hydroxybenzoic acid.

Examples of the aliphatic dicarboxylic acids having 2 to 20 carbon atoms include oxalic acid, malonic acid, succinic acid, methylsuccinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, and decane. Examples include, but are not limited to, dicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, tridecanedicarboxylic acid, tetradecanedicarboxylic acid, pentadecanedicarboxylic acid, hexadecanedicarboxylic acid, heptadecanedicarboxylic acid, octadecanedicarboxylic acid, and the like. Among them, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, tridecanedicarboxylic acid, tetradecanedicarboxylic acid, pentadecanedicarboxylic acid, hexadecanedicarboxylic acid, Heptadecanedicarboxylic acid and octadecanedicarboxylic acid are preferred, and azelaic acid and sebacic acid are more preferred.

Examples of the carboxylic acid monoamide include, but are not limited to, those in which one carboxy group of the aliphatic dicarboxylic acid is amidated. Among these, azelaic acid or sebacic acid in which one carboxy group is amidated is preferred. Examples of amines used for amidation include aliphatic primary amines such as butylamine, amylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, laurylamine, myristylamine, palmitylamine, stearylamine, and behenylamine; Aliphatic secondary amines such as dipropylamine, diisopropylamine, dibutylamine, diamylamine, dilaurylamine, monomethyllaurylamine, distearylamine, monomethylstearylamine, dimyristylamine, dipalmitylamine; allylamine, diallylamine, oleylamine , aliphatic unsaturated amines such as dioleylamine; cycloaliphatic amines such as cyclopropylamine, cyclobutylamine, cyclopentylamine, cyclohexylamine; aniline, methylaniline, ethylaniline, benzylamine, dibenzylamine, diphenylamine, α-naphthylamine Examples include aromatic amines such as, but are not limited to. Among these, hexylamine, heptylamine, octylamine, nonylamine, decylamine, laurylamine, myristylamine, palmitylamine, stearylamine, behenylamine, dibutylamine, diamylamine, monomethyllaurylamine, monomethylstearylamine, and oleylamine are preferred.

The content of barium composite soap in the grease composition of the present invention is not particularly limited, but is preferably 3 to 50% by mass, more preferably 15 to 45% by mass, and 20 to 43% by mass. is more preferable, particularly preferably 25 to 40% by weight, and most preferably 30 to 35% by weight. By keeping the content of the barium composite soap within an appropriate range, it is possible to achieve both load-bearing properties and abrasion resistance to a higher degree.

The grease composition of the present invention may further contain other thickeners other than the barium complex soap as long as the effects of the present invention are achieved. Other thickeners include soap-based thickeners such as lithium soap, lithium complex soap, calcium soap, calcium complex soap, aluminum soap, and aluminum complex soap; urea-based thickeners such as diurea compounds, triurea compounds, and tetraurea compounds. Examples include, but are not limited to, thickening agent; bentonite; silica gel; fluororesin; and the like.

[Organic molybdenum compound]
The grease composition of the present invention contains an organic molybdenum compound. Examples of the organic molybdenum compound include, but are not limited to, molybdenum dithiocarbamate (MoDTC), molybdenum dithiophosphate (MoDTP), and the like. One type of organic molybdenum compound may be used alone, or two or more types may be used in combination.

The content of the organic molybdenum compound in the grease composition of the present invention is 0.25 to 10% by mass in terms of molybdenum. The grease composition of the present invention can achieve both load-bearing properties and wear resistance by using a barium composite soap as a thickener and containing an organic molybdenum compound in the above content.

The content of the organic molybdenum compound in terms of molybdenum can be calculated by multiplying the content of the organic molybdenum compound used by the mass percentage occupied by molybdenum in the organic molybdenum compound. For example, if the grease composition contains 5% by mass of an organic molybdenum compound and the mass proportion of molybdenum in the organic molybdenum compound is 10% by mass, the content of the organic molybdenum compound in the grease composition is expressed in terms of molybdenum. 5×(10/100)=0.5% by mass.

The content of the organic molybdenum compound in the grease composition of the present invention is preferably 0.6 to 5% by mass, more preferably 0.7 to 4% by mass, and 0.8 to 3% by mass in terms of molybdenum. More preferably, it is .5% by weight, particularly preferably from 1 to 3% by weight, and most preferably from 1.5 to 2.5% by weight. When the content of the organic molybdenum compound is within an appropriate range, it is possible to achieve both higher load resistance and wear resistance. Further, by setting the content of the organic molybdenum compound within an appropriate range, corrosion of metal due to molybdenum can be prevented.

In the grease composition of the present invention, the content of the organic molybdenum compound (in terms of molybdenum) is preferably 0.75 to 30 parts by mass, and preferably 1.5 to 15 parts by mass, based on 100 parts by mass of barium composite soap. The amount is more preferably 2 to 12 parts by weight, even more preferably 2.5 to 10 parts by weight, particularly preferably 3 to 8 parts by weight, and 5 to 7 parts by weight. Most preferably.

[Other ingredients]
The grease composition of the present invention may contain other components as long as the effects of the present invention are achieved. Examples of other components include, but are not limited to, extreme pressure agents other than organic molybdenum compounds, antioxidants, rust preventives, oiliness agents, viscosity index improvers, and the like.

Examples of extreme pressure agents other than organic molybdenum compounds include phosphorus compounds such as phosphate esters, phosphite esters, and phosphate ester amines; sulfur compounds such as sulfides and disulfides; and organic compounds such as metal dithiophosphates and metal dithiocarbamates. Examples include, but are not limited to, metal compounds (excluding organic molybdenum compounds).

Examples of the antioxidant include, but are not limited to, amine antioxidants, phenolic antioxidants, phosphorus antioxidants, and the like.
Examples of amine antioxidants include alkylated diphenylamine, triphenylamine, phenyl-α-naphthylamine, phenothiazine, alkylated α-naphthylamine, alkylated phenothiazine, and 4,4'-bis(α,α-dimethylbenzyl)diphenylamine. , N,N'-di-2-naphthyl-p-phenylenediamine, N,N'-diphenyl-p-phenylenediamine, N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine, Examples include, but are not limited to, N-phenyl-N'-isopropyl-p-phenylenediamine.

Examples of phenolic antioxidants include 2,6-di-tert-butyl-4-methylphenol, pentaerythritol tetrakis [3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], and octadecyl. -3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 1,3,5-tris(3,5-di-t-butyl-4-hydroxyphenylmethyl)-2,4, 6-trimethylbenzene, 1,3,5-tris(3,5-di-t-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)- Examples include, but are not limited to, trion and the like.

Examples of phosphorus antioxidants include alkyl phosphites, alkylaryl phosphites, and arylphosphites. Examples of arylphosphites include triphenyl phosphite, tricresyl phosphite, tris(ethylphenyl) phosphite, tris(nonylphenyl) phosphite, and tris(2,4-di-t-butylphenyl) phosphite. etc., but are not limited to these.

Examples of rust preventives include calcium salts or sodium salts of aromatic sulfonic acids or saturated aliphatic dicarboxylic acids, fatty acids, fatty acid amines, alkylsulfonic acid metal salts, alkylsulfonic acid amine salts, paraffin oxides, polyoxyalkyl ethers, etc. These include, but are not limited to:

Examples of the oily agent include, but are not limited to, fatty acids or esters thereof, higher alcohols, polyhydric alcohols or esters thereof, aliphatic esters, aliphatic amines, fatty acid monoglycerides, montan wax, and amide waxes.

Examples of the viscosity index improver include, but are not limited to, polymethacrylate, ethylene-propylene copolymer, polyisobutylene, polyalkylstyrene, hydrogenated styrene-isoprene copolymer, and the like.

The grease composition of the present invention can be manufactured by mixing the above-mentioned components using a known method. At that time, the order of mixing each component is not particularly limited.

The grease composition of the present invention preferably has a fusion load of 3900 N or more as measured in accordance with ASTM D2596, and a wear scar diameter of 0.45 mm or less as measured in accordance with ASTM D2266. The fusion load and wear scar diameter are evaluated by a four-ball test. Note that the fusion load and the wear scar diameter can be measured according to the conditions described in Examples.

The grease composition of the present invention preferably has a fusion load of 4000N or more, even more preferably 5000N or more, particularly preferably 6000N or more, and preferably 7000N or more, as measured in accordance with ASTM D2596. Most preferred. Further, the grease composition of the present invention preferably has a wear scar diameter of 0.42 mm or less, even more preferably 0.40 mm or less, and particularly 0.38 mm or less as measured in accordance with ASTM D2266. Preferably, it is most preferably 0.36 mm or less.

The grease composition of the present invention is suitable for lubricating applications where heavy loads are applied, such as reduction gear gears, ball screws, and bearings, but may also be used for other applications, such as office equipment such as copying machines and printers, as necessary. Parts: Reducers/speed increasers, gears, chains, power transmission devices such as motors, driving system parts, braking system parts such as ABS, steering system parts, drive system parts such as transmissions, steering devices, power window motors, Automotive parts such as power seat motors and sunroof motors; Hinge parts for electronic information equipment and mobile phones; Food and drug industries, steel, construction, glass industry, cement industry, chemical, rubber and resin industries such as film tenters, environment and It can be widely applied to various parts in power equipment, paper manufacturing/printing industry, wood industry, textile/apparel industry; and other mechanical parts that move relative to each other.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples in any way.

[Preparation of grease composition]
(1) Base oil (1a) Poly α-olefin 1 (PAO1): Synfluid PAO 6cSt (manufactured by Chevron Phillips Chemical), 40°C kinematic viscosity 30mm ² /s
(1b) Poly α-olefin 2 (PAO2): mixture of two commercially available poly α-olefin base oils, kinematic viscosity 100 mm ² /s at 40°C

(2) Thickener (2a) Barium complex soap (Ba-comp): 27.5% by mass of sebacic acid, 41.5% by mass of carboxylic acid monostearylamide, and 31% by mass of barium hydroxide are reacted in base oil. (2b) Lithium soap (Li soap): Lithium composite soap obtained by reacting 88% by mass of 12-hydroxystearic acid and 12% by mass of lithium hydroxide in base oil (2c) Lithium composite soap (Li-comp): Diurea compound obtained by reacting 63.5% by mass of 12-hydroxystearic acid, 19% by mass of azelaic acid, and 17.5% by mass of lithium hydroxide in base oil (2d) Diurea compound: Obtained by reacting 50% by mass of diphenylmethane diisocyanate and 50% by mass of octylamine in base oil

(3) Additives (additives containing organic molybdenum compounds)
(3a) Molybdenum dithiocarbamate 1 (MoDTC1): ADEKA Sakura Lube (registered trademark) 600 (manufactured by ADEKA Corporation), molybdenum content approximately 28% by mass
(3b) Molybdenum dithiocarbamate 2 (MoDTC2): ADEKA Sakura Lube (registered trademark) 525 (manufactured by ADEKA Corporation), molybdenum content approximately 10% by mass
(3c) Molybdenum dithiocarbamate 3 (MoDTC3): ADEKA Sakura Lube (registered trademark) 165 (manufactured by ADEKA Corporation), molybdenum content approximately 4.5% by mass
(3d) Molybdenum dithiophosphate (MoDTP): ADEKA Sakura Lube (registered trademark) 300 (manufactured by ADEKA Corporation), molybdenum content approximately 9% by mass

Additives were added to the above mixture of base oil and thickener so as to have the blending ratios shown in Tables 1 to 3, and the mixture was mixed to obtain uniform grease compositions (Examples 1 to 10, Comparative Examples 1-16). In addition, the numerical value of the compounding amount in each table is mass %. Note that "(Mo amount)" in each table represents the content of the organic molybdenum compound expressed in terms of molybdenum.

[Evaluation of grease composition]
The obtained grease composition was subjected to the following fusion load test and wear scar diameter test. The results are shown in Tables 1 to 3.

-Fusion load test According to ASTM D2596, it was measured by a four-ball test under the following conditions.
Rotation speed: 1770rpm
Time: 10 seconds Temperature: Room temperature

- Wear scar diameter test According to ASTM D2266, measurement was performed by a four-ball test under the following conditions.
Rotation speed: 1200rpm
Time: 60 minutes Temperature: 75℃

From the results of Examples 1 to 10, it was found that the composition contained a base oil, a thickener that is a barium complex soap, and an organic molybdenum compound, and the content of the organic molybdenum compound was 0.25 to 10% by mass in terms of molybdenum. It can be seen that the grease composition has excellent load-bearing properties and wear resistance.

From the results of Examples 2 to 6, in addition to the above, the content of the organic molybdenum compound is 0.6 to 5% by mass in terms of molybdenum, so that the grease composition has better load carrying capacity and wear resistance. It can be seen that both are highly compatible.

From the results of Examples 4 and 6, in addition to the above, by having a kinematic viscosity of the base oil of 15 to 50 mm ² /s at 40°C, the grease composition has higher load carrying capacity and wear resistance. I understand that both can be achieved.

From the results of Comparative Examples 1 to 5 and 12 to 16, it is found that when the content of the organic molybdenum compound is less than 0.25% by mass in terms of molybdenum, it is not possible to sufficiently achieve both load resistance and wear resistance. Recognize.

Comparing the results of Comparative Examples 6 and 7, when lithium soap is used as a thickener, the load carrying capacity is improved when the content of the organic molybdenum compound is 0.25 to 10% by mass in terms of molybdenum. However, it can be seen that the wear resistance does not improve, but rather decreases.

Comparing the results of Comparative Examples 8 and 9, when a lithium composite soap is used as a thickener, the load carrying capacity is improved when the content of the organic molybdenum compound is 0.25 to 10% by mass in terms of molybdenum. However, it can be seen that the wear resistance does not improve, but rather decreases.

Comparing the results of Comparative Examples 10 and 11, when a diurea compound is used as a thickener, the wear resistance is improved when the content of the organic molybdenum compound is 0.25 to 10% by mass in terms of molybdenum. However, it can be seen that the effect of improving load resistance is limited.

That is, from the results of Examples 1 to 10 and Comparative Examples 6 to 11, barium composite soap was used as the thickener, and the content of the organic molybdenum compound was 0.25 to 10% by mass in terms of molybdenum. It can be seen that in only certain cases, a grease composition can have both load carrying capacity and wear resistance.

FIG. 1 is a semi-logarithmic plot showing the relationship between the molybdenum equivalent content of an organic molybdenum compound and the fusion load of a grease composition in Examples and Comparative Examples. As can be seen from Figure 1, when barium composite soap is used as a thickener and the content of organic molybdenum compound is 0.25% by mass or more in terms of molybdenum, the fusion load is significantly improved. .

The grease composition of the present invention can be particularly suitably used for lubricating areas where heavy loads are applied, such as reduction gear gears, ball screws, and bearings.

Claims (5)

A grease composition comprising a base oil, a thickener which is a barium complex soap, and an organic molybdenum compound, wherein the content of the organic molybdenum compound is 0.25 to 10% by mass in terms of molybdenum. The grease composition according to claim 1, wherein the content of the organic molybdenum compound is 0.6 to 5% by mass in terms of molybdenum. The grease composition according to claim 1 or 2, wherein the content of the barium composite soap is 15 to 45% by mass. The grease composition according to claim 1 or 2, wherein the base oil has a kinematic viscosity of 15 to 100 mm ² /s at 40°C. The grease composition according to claim 1 or 2, wherein the fusion load measured according to ASTM D2596 is 3900 N or more, and the wear scar diameter measured according to ASTM D2266 is 0.45 mm or less.

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