Grease composition

Abstract

A grease composition containing a base oil (A), a thickener (B), an organic molybdenum compound (C) and an organic zinc compound (D), wherein the base oil (A) contains a mineral oil (A1), the thickener (B) contains a lithium complex soap (B1), and the base oil (A) has a kinematic viscosity of 100 mm2 / s or more at 40°C.

Description

Grease composition

[0001] This invention relates to a grease composition. This application claims priority under Japanese Patent Application No. 2024-215421, filed in Japan on December 10, 2024, the contents of which are incorporated herein by reference.

[0002] Grease is a lubricant made by dispersing a highly lipophilic solid thickener in a base oil to create a semi-solid substance. Compared to lubricating oil, grease adheres more easily to the lubricating part and is less likely to leak. Therefore, using grease can simplify the mechanical structure of the lubrication system. In addition, grease leaks less than lubricating oil, creating a cleaner environment, and the replenishment interval can be shortened. Grease is mainly used to lubricate mechanical elements such as rolling bearings, sliding bearings, ball screws, linear guides, and gears. Rolling bearings are widely used in machine tool spindles, railway vehicles, engine accessories such as alternators in automobiles, constant velocity joints, and wheels.

[0003] For example, Patent Document 1 discloses a resin grease composition comprising (A) a lubricating oil base, (B) a thickener, and (C) at least one selected from the group consisting of organic molybdenum compounds and sulfur-based extreme pressure agents, wherein, when a sulfur-based extreme pressure agent is included, the content of the sulfur-based extreme pressure agent is 0.05% by mass or more and 2.5% by mass or less on a basis of the total amount of the composition, and substantially free of zinc dialkyldithiophosphate. It is disclosed that this resin grease composition does not degrade the resin it is in contact with, particularly acetal resin, even under high-temperature conditions.

[0004] Japanese Patent Publication No. 2022-092773

[0005] The properties required for a grease composition vary depending on its intended use, and the optimal base oil, thickener, and additives are selected according to the application. Therefore, there is a need for grease compositions that exhibit excellent properties not only under high-temperature conditions as described in Patent Document 1, but also under high-load conditions.

[0006] The present invention has been made in view of the above circumstances, and aims to provide a grease composition with high wear resistance and load-bearing capacity.

[0007] In order to solve the above problems, the present invention adopts the following configuration. [1] A grease composition containing a base oil (A), a thickener (B), an organic molybdenum compound (C), and an organic zinc compound (D), wherein the base oil (A) includes a mineral oil (A1), the thickener (B) includes a lithium complex soap (B1), and the base oil (A) has a kinematic viscosity at 40 °C of 100 mm ２ / s or more. [2] The grease composition according to [1], wherein the base oil (A) has a kinematic viscosity at 40 °C of 200 mm ２ / s or more and 250 mm ２ / s or less. [3] The grease composition according to [1] or [2], which is used for industrial machinery. [4] The grease composition according to any one of [1] to [3], wherein the organic molybdenum compound (C) includes molybdenum dithiocarbamate. [5] The grease composition according to any one of [1] to [4], wherein the organic zinc compound (D) includes one or more compounds selected from the group consisting of zinc dialkyldithiophosphate and zinc dithiocarbamate.

[0008] According to the present invention, a grease composition having high abrasion resistance and load-carrying capacity can be provided.

[0009] (Grease Composition) The grease composition of the present embodiment contains a base oil (A), a thickener (B), an organic molybdenum compound (C), and an organic zinc compound (D).

[0010] <Base Oil (A)> The grease composition of the present embodiment contains a base oil (A). The kinematic viscosity of the base oil (A) at 40 °C is 100 mm ２ / s or more, preferably 140 mm ２ / s or more, more preferably 180 mm ２ / s or more, and even more preferably 200 mm ２ / s or more. The kinematic viscosity of the base oil (A) at 40 °C is preferably 300 mm ２ / s or less, more preferably 280 mm ２ / s or less, and even more preferably 250 mm ２ / s or less.

[0011] The kinematic viscosity of the base oil (A) of the grease composition of this embodiment at 40°C is 100 mm². ２ If the kinematic viscosity is greater than or equal to / s, the wear resistance and load-bearing capacity will be higher. Furthermore, if the kinematic viscosity of the base oil (A) at 40°C is above the above preferred lower limit, the wear resistance and load-bearing capacity will be even higher. If the kinematic viscosity of the base oil (A) of the grease composition of this embodiment at 40°C is below the above preferred upper limit, the torque will be even lower.

[0012] For example, the kinematic viscosity of base oil (A) at 40°C is 100 mm². ２ / s or more 300mm ２ Preferably less than / s, and 140 mm ２ / s or more 300mm ２ / s or less is more preferable, and 180 mm ２ / s or more 280mm ２ A value of / s or less is even more preferable, and 200 mm ２ / s or more 250mm ２ A value of / s or less is particularly preferred.

[0013] The kinematic viscosity of base oil (A) at 100°C is 17 mm². ２ Preferably 18 mm / s or more. ２ / s or more is more preferable, and 19 mm ２ A value of 0 / s or higher is even more preferable. The kinematic viscosity of base oil (A) at 100°C is 35 mm². ２ Preferably less than / s, and 30 mm ２ / s or less is more preferable, and 25 mm ２ A value of / s or less is even more preferable.

[0014] If the kinematic viscosity of the base oil (A) of the grease composition of this embodiment at 100°C is above the above preferred lower limit, the wear resistance and load-bearing capacity will be higher. If the kinematic viscosity of the base oil (A) of the grease composition of this embodiment at 100°C is below the above preferred upper limit, the torque will be lower.

[0015] For example, the kinematic viscosity of base oil (A) at 100°C is 17 mm². ２ / s or more 35mm ２ Preferably less than / s, and 18 mm ２ / s or more 30mm ２Less than or equal to 19 mm / s is more preferable, and 19 mm / s or more is even more preferable. ２ / s or more is even more preferable.

[0016] The kinematic viscosities at 40 °C and 100 °C in this specification mean the kinematic viscosities measured in accordance with JIS K2283:2000.

[0017] The viscosity index of the base oil (A) of the grease composition of this embodiment is preferably 70 or more, more preferably 80 or more, and even more preferably 90 or more. The viscosity index of the base oil (A) is preferably 150 or less, more preferably 120 or less, and even more preferably 100 or less. For example, the viscosity index of the base oil (A) is preferably 70 or more and 150 or less, more preferably 80 or more and 120 or less, and even more preferably 90 or more and 100 or less.

[0018] The viscosity index in this specification means the value measured in accordance with JIS K 2283.

[0019] The aniline point of the base oil (A) of the grease composition of this embodiment is preferably 90 °C or more, more preferably 100 °C or more, and even more preferably 110 °C or more. The aniline point of the base oil (A) is preferably 140 °C or less, more preferably 130 °C or less, and even more preferably 120 °C or less. For example, the aniline point of the base oil (A) is preferably 90 °C or more and 140 °C or less, more preferably 100 °C or more and 130 °C or less, and even more preferably 110 °C or more and 120 °C or less.

[0020] The aniline point in this specification means the value measured in accordance with JIS K 2256.

[0021] The sulfur content of the base oil (A) of the grease composition of this embodiment is preferably 0.40% by mass or more, more preferably 0.45% by mass or more, and even more preferably 0.50% by mass or more. The sulfur content of the base oil (A) is preferably 0.70% by mass or less, more preferably 0.65% by mass or less, and even more preferably 0.60% by mass or less. For example, the density of the base oil (A) at 20 °C is preferably 1.30 or more and 1.60 or less, more preferably 1.35 or more and 1.55 or less, and even more preferably 1.40 or more and 1.50 or less.

[0022] In this specification, sulfur content refers to values ​​measured in accordance with JIS K 2541-6.

[0023] The %C of the base oil (A) of the grease composition of this embodiment Ｐ It is preferably 55 or higher, more preferably 60 or higher, and even more preferably 65 or higher. %C of base oil (A) Ｐ It is preferably 80 or less, more preferably 75 or less, and even more preferably 70 or less.

[0024] The %C of the base oil (A) of the grease composition of this embodiment Ｎ It is preferably 10 or more, more preferably 15 or more, and even more preferably 20 or more. %C of base oil (A) Ｎ It is preferably 35 or less, more preferably 30 or less, and even more preferably 25 or less.

[0025] The %C of the base oil (A) of the grease composition of this embodiment Ａ It is preferably 1 or more, more preferably 3 or more, and even more preferably 5 or more. %C of base oil (A) Ｎ It is preferably 15 or less, more preferably 10 or less, and even more preferably 8 or less.

[0026] For example, the base oil (A) of the grease composition of this embodiment is %C Ｐ , %C Ｎ and %C Ａ Of the total of 100, %C Ｐ The %C of base oil (A) is preferably 55 to 80, more preferably 60 to 75, and even more preferably 65 to 70. Ｎ The %C of the base oil (A) is preferably 10 to 35, more preferably 15 to 30, and even more preferably 20 to 25. Ａ It is preferably 1 to 15, more preferably 3 to 10, and even more preferably 5 to 8.

[0027] In this specification, %C Ｐ , %C Ｎ and %C Ａ These are determined by methods (n-d-M ring analysis) in accordance with ASTM D 3238-85. %C Ｎ This represents the percentage (mass ratio) of the number of naphthenic carbon atoms relative to the total number of carbon atoms. %C Ｐ This represents the percentage (mass ratio) of the number of carbon atoms in paraffin to the total number of carbon atoms. %C Ａ This represents the percentage of aromatic carbon atoms relative to the total number of carbon atoms. (See %C mentioned above.) Ｎ , %C Ｐ and %C Ａ The preferred range is based on the value obtained by the above method, and even for mineral oil-based base oils that do not contain naphthenes, the %C obtained by the above method is also applicable. Ｎ This can represent a value greater than 0.

[0028] For example, if the base oil (A) is mineral oil, the parameters of the base oil (A) described above can be controlled by precisely adjusting the pressure, temperature, reflux ratio, or the number of stages in the distillation column during the production of the mineral oil.

[0029] The base oil (A) of the grease composition of this embodiment includes mineral oil (A1).

[0030] ≪Mineral Oil (A1)≫ As mineral oil (A1), distillate obtained by atmospheric distillation of crude oil can be used. In addition, lubricating oil fractions obtained by further vacuum distillation of this distillate and then refined through various refining processes can also be used. As refining processes, hydrorefining, solvent extraction, solvent dewaxing, hydrodewaxing, sulfuric acid washing, and clay treatment can be combined as appropriate. Mineral oil can be obtained by processing these refining processes in an appropriate order. Alternatively, a mixture of multiple refined oils with different properties obtained by subjecting different crude oils or distillates to different refining process combinations may be used.

[0031] As the mineral oil (A1), you may use a Group I base oil (hereinafter referred to as "API Group I base oil"), a Group II base oil (hereinafter referred to as "API Group II base oil"), or a Group III base oil (hereinafter referred to as "API Group III base oil") according to the API base oil classification, or a mixture thereof. API Group I base oil is a mineral oil-based base oil with a sulfur content of more than 0.03% by mass and / or a saturation content of less than 90% by mass, and a viscosity index of 80 or more and less than 120. API Group II base oil is a mineral oil-based base oil with a sulfur content of 0.03% by mass or less, a saturation content of 90% by mass or more, and a viscosity index of 80 or more and less than 120. API Group III base oil is a mineral oil-based base oil with a sulfur content of 0.03% by mass or less, a saturation content of 90% by mass or more, and a viscosity index of 120 or more.

[0032] The base oil (A) of the grease composition in this embodiment may be a single mineral oil or a mixture of multiple mineral oils. In a mixture of multiple mineral oils, the API classifications of those mineral oils may be the same or different.

[0033] The base oil (A) of the grease composition of this embodiment may contain synthetic oil.

[0034] <<Synthetic Oils>> Examples of synthetic oils include polyolefins such as poly-α-olefins, ester base oils such as diesters and polyol esters, polyalkylene glycols, alkylbenzenes, and alkylnaphthalenes. The base oil (A) of the grease composition of this embodiment may be a single synthetic oil or a mixture of multiple synthetic oils.

[0035] The base oil (A) content of the grease composition of this embodiment is preferably 70% by mass or more, more preferably 75% by mass or more, and even more preferably 80% by mass or more, based on the total amount of the grease composition. The base oil (A) content of the grease composition of this embodiment is preferably 98% by mass or less, more preferably 95% by mass or less, and even more preferably 90% by mass or less, based on the total amount of the grease composition. For example, the base oil (A) content of the grease composition of this embodiment is preferably 70% by mass or more and 98% by mass or less, more preferably 75% by mass or more and 95% by mass or less, and even more preferably 80% by mass or more and 90% by mass or less, based on the total amount of the grease composition.

[0036] In the grease composition of this embodiment, the proportion of mineral oil (A1) in the total amount of base oil (A) is preferably 95% by mass or more, preferably 98% by mass or more, and more preferably 99% by mass or more. In particular, the base oil (A) of the grease composition of this embodiment is preferably composed solely of mineral oil (A1).

[0037] <Thickener (B)> The grease composition of this embodiment contains a thickener (B). The thickener (B) contains lithium complex soap (B1).

[0038] ≪Lithium Complex Soap (B1)≫ Lithium complex soap (B1) is a metallic soap made by saponifying multiple fatty acids or oils with lithium hydroxide, etc.

[0039] The fatty acid may be a fatty acid derivative having substituents such as a hydroxyl group. The fatty acid is preferably a monovalent or divalent fatty acid. The fatty acid is preferably a fatty acid having 6 to 20 carbon atoms, and more preferably a monovalent fatty acid having 12 to 20 carbon atoms or a divalent fatty acid having 6 to 14 carbon atoms. In this invention, "6 to 20 carbon atoms" means having 6 to 20 carbon atoms.

[0040] Among the above, a monovalent fatty acid containing one hydroxyl group is preferred as the fatty acid. Examples of dibasic acids to be combined with fatty acids in lithium complex soap (B1) include acetic acid, azelaic acid, and sebacic acid. Examples of aromatic carboxylic acids to be combined with fatty acids in lithium complex soap (B1) include benzoic acid.

[0041] Among the lithium complex soaps (B1) mentioned above, lithium complex soaps obtained by reacting lithium hydroxide with a monovalent fatty acid having 6 to 20 carbon atoms containing one hydroxyl group and a dibasic acid are preferred, lithium complex soaps obtained by reacting lithium hydroxide with a monovalent fatty acid having 12 to 20 carbon atoms containing one hydroxyl group and azelaic acid are more preferred, and lithium complex soaps obtained by reacting lithium hydroxide with 12-hydroxystearic acid and azelaic acid are even more preferred.

[0042] Lithium complex soap (B1) may be used alone or in combination with other types.

[0043] The thickener (B) may contain other thickeners besides lithium complex soap (B1). Examples of other thickeners include single soaps; metal complex soaps other than lithium; urea-based thickeners; bentonite; and inorganic thickeners such as silica gel. Examples of urea-based thickeners include diurea compounds and polyurea compounds. Diurea compounds are compounds obtained by the reaction of diisocyanate with a monoamine and have two urea groups (-NH-CO-NH-). In this specification, polyurea compounds are compounds obtained by the reaction of diisocyanate with a monoamine or diamine and have three or more urea groups (-NH-CO-NH-).

[0044] The thickener (B) may be used alone or in a mixture of several types. The content of the thickener (B) in the grease composition of this embodiment is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more, based on the total amount of the grease composition. The content of the thickener (B) in the grease composition of this embodiment is preferably 15% by mass or less, more preferably 12% by mass or less, and even more preferably 10% by mass or less, based on the total amount of the grease composition. For example, the content of the thickener (B) in the grease composition of this embodiment is preferably 1% by mass or more and 15% by mass or less, more preferably 3% by mass or more and 12% by mass or less, and even more preferably 5% by mass or more and 10% by mass or less, based on the total amount of the grease composition.

[0045] In this embodiment, the proportion of lithium complex soap (B1) in the total amount of thickener (B) of the grease composition is preferably 95% by mass or more, preferably 98% by mass or more, and more preferably 99% by mass or more. It is particularly preferable that the thickener (B) of the grease composition in this embodiment consists solely of lithium complex soap (B1).

[0046] <Organo-molybdenum compound (C)> The grease composition of this embodiment contains an organic-molybdenum compound (C). Examples of organic-molybdenum compound (C) include molybdenum dithiocarbamate (MoDTC), molybdenum dithiophosphate (MoDTP), and Mo-amine complex. Molybdenum dithiocarbamate is preferred as the organic-molybdenum compound, and molybdenum dithiocarbamate represented by the following formula (1) is more preferred.

[0047] [In the formula, R1 to R4 may be the same or different, and each is a hydrocarbon group having 1 to 30 carbon atoms, X １ ~X ４ These may be the same or different, and are either S or O, respectively.

[0048] In formula (1) above, the hydrocarbon groups in R1 to R4 have 1 to 30 carbon atoms, preferably 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and even more preferably 1 to 4 carbon atoms.

[0049] In formula (1) above, the hydrocarbon groups in R1 to R4 are preferably cyclic alkyl groups or linear alkyl groups, and more preferably linear alkyl groups.

[0050] The organic molybdenum compound (C) may be used alone or in a mixture of several. The content of the organic molybdenum compound (C) in the grease composition of this embodiment is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.15% by mass or more, based on the total amount of the grease composition. The content of the organic molybdenum compound (C) in the grease composition of this embodiment is preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 6% by mass or less, based on the total amount of the grease composition. For example, the content of the organic molybdenum compound (C) in the grease composition of this embodiment is preferably 0.05% by mass or more and 10% by mass or less, more preferably 0.1% by mass or more and 8% by mass or less, and even more preferably 0.15% by mass or more and 6% by mass or less, based on the total amount of the grease composition.

[0051] In the grease composition of this embodiment, the proportion of molybdenum dithiocarbamate in the total amount of organic molybdenum compound (C) is preferably 95% by mass or more, preferably 98% by mass or more, and more preferably 99% by mass or more. In the grease composition of this embodiment, it is particularly preferable that the organic molybdenum compound (C) consists solely of molybdenum dithiocarbamate.

[0052] <Organozinc Compound (D)> The grease composition of this embodiment contains an organozinc compound (D). Examples of organozinc compound (D) include zinc dialkyldithiophosphate and zinc dialkyldithiocarbamate. Zinc dialkyldithiophosphate is preferred as the organozinc compound (D), and zinc dialkyldithiophosphate represented by the following formula (2) is more preferred.

[0053] [In the formula, R19 to R22 may be the same or different, and each independently represents a hydrocarbon group having one or more carbon atoms.]

[0054] In formula (2) above, the hydrocarbon groups in R19 to R22 preferably have 1 to 30 carbon atoms, more preferably 1 to 10 carbon atoms, even more preferably 2 to 8 carbon atoms, and particularly preferably 3 to 6 carbon atoms.

[0055] In formula (2) above, the hydrocarbon groups in R19 to R22 are preferably cyclic alkyl groups or linear alkyl groups, and more preferably linear alkyl groups.

[0056] The organozinc compound (D) may be used alone or in a mixture of several. The content of the organozinc compound (D) in the grease composition of this embodiment is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.15% by mass or more, based on the total amount of the grease composition. The content of the organozinc compound (D) in the grease composition of this embodiment is preferably 10% by mass or less, more preferably 8% by mass or less, and even more preferably 6% by mass or less, based on the total amount of the grease composition. For example, the content of the organozinc compound (D) in the grease composition of this embodiment is preferably 0.05% by mass or more and 10% by mass or less, more preferably 0.1% by mass or more and 8% by mass or less, and even more preferably 0.15% by mass or more and 6% by mass or less, based on the total amount of the grease composition.

[0057] In the grease composition of this embodiment, the proportion of zinc dialkyldithiophosphate in the total amount of organozinc compound (D) is preferably 95% by mass or more, preferably 98% by mass or more, and more preferably 99% by mass or more. In particular, the organozinc compound (D) of the grease composition of this embodiment is preferably composed solely of zinc dialkyldithiophosphate.

[0058] <Optional Components> The grease composition of this embodiment may contain optional components other than the base oil (A), thickener (B), organic molybdenum compound (C), and organic zinc compound (D) described above. Examples of such optional components include solid lubricants, anti-wear agents or extreme pressure agents, antioxidants, rust inhibitors, and corrosion inhibitors.

[0059] Examples of solid lubricants include graphite, graphite fluoride, melamine cyanurate, polytetrafluoroethylene, molybdenum disulfide, antimony sulfide, boron nitride, and alkali (earth) metal borates. When the grease composition contains a solid lubricant, its content is, for example, 0.1 to 20% by mass of the total amount of the grease composition. The solid lubricant may be used alone or in a mixture of multiple solid lubricants.

[0060] Examples of anti-wear agents or extreme pressure agents include sulfur-containing compounds such as dihydrocarbyl polysulfide, sulfur esters, thiazole compounds, and thiadiazole compounds; and phosphorus-based extreme pressure agents such as phosphate esters, acidic phosphate esters, amine salts of acidic phosphate esters, and phosphite esters. When a grease composition contains an anti-wear agent or extreme pressure agent, its content is, for example, 0.1 to 10% by mass of the total amount of the grease composition. The anti-wear agent or extreme pressure agent may be used alone, or multiple anti-wear agents or extreme pressure agents may be used in mixture form.

[0061] Examples of antioxidants include phenolic compounds such as 2,6-di-t-butylphenol and 2,6-di-t-butyl-p-cresol; and amine compounds such as diphenylamine, dialkyldiphenylamine, phenyl-α-naphthylamine, and p-alkylphenyl-α-naphthylamine. When the grease composition contains an antioxidant, its content is, for example, 0.5 to 10% by mass of the total amount of the grease composition. The antioxidant may be used alone or in combination of multiple antioxidants.

[0062] Examples of rust inhibitors include amines, neutral or overbasic petroleum-based or synthetic oil-based metal sulfonates, carboxylate metal salts, esters, phosphoric acid, phosphates, and ester-based rust inhibitors. Examples of neutral or overbasic petroleum-based or synthetic oil-based metal sulfonates include alkaline earth metal salts of sulfonic acids, specifically dinonylnaphthalene sulfonate calcium salt. Examples of ester-based rust inhibitors include partial esters of polyhydric alcohols, esterified oxide waxes, esterified lanolin fatty acids, alkyl or alkenyl succinate esters. Examples of partial esters of polyhydric alcohols include sorbitan isostearate. When the grease composition contains a rust inhibitor, its content is, for example, 0.005 to 5% by mass of the total amount of the grease composition. The rust inhibitor may be used alone or in combination of multiple rust inhibitors.

[0063] As corrosion inhibitors, known corrosion inhibitors such as benzotriazole compounds, toltriazole compounds, thiadiazole compounds, and imidazole compounds can be used. When the grease composition contains a corrosion inhibitor, its content is, for example, 0.01 to 10% by mass of the total amount of the grease composition. The corrosion inhibitor may be used alone or in a mixture of multiple corrosion inhibitors.

[0064] The grease composition of this embodiment contains a base oil (A), a thickener (B), an organic molybdenum compound (C), and an organic zinc compound (D), wherein the base oil (A) contains mineral oil (A1), the thickener (B) contains lithium complex soap (B1), and the kinematic viscosity of the base oil (A) at 40°C is 100 mm². ２ The viscosity is 1 / s or more. The grease composition of this embodiment combines a relatively high viscosity base oil (A), a thickener lithium complex soap (B1), and specific additives (organo-molybdenum compound (C) and organo-zinc compound (D)), resulting in high load-bearing capacity and wear resistance.

[0065] [Applications] The grease composition of this embodiment has high load-bearing capacity and wear resistance, and is therefore particularly preferable for use in industrial machinery.

[0066] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0067] <Preparation of Grease Compositions> The grease compositions of Examples 1 to 9 and Comparative Examples 1 to 3 were prepared according to the blending ratios shown in Tables 2 and 3. The values ​​in Table 2 represent the percentage (by mass) of each component relative to the total grease composition.

[0068] (1) Base oil (A) ・(A)-1: Mineral oil with parameters shown in Table 1 ・(A)-2: Mineral oil with parameters shown in Table 1

[0069]

[0070] (2) Thickeners (B) ・(B)-1: Li complex soap (Li complex soap obtained by the reaction of lithium hydroxide, 12-hydroxystearic acid, and azelaic acid) ・(b)-1: Urea compound (Urea thickener obtained by the reaction of an amine compound and an isocyanate compound)

[0071] (3) Organic molybdenum compound (C) ・(C)-1:MoDTC (a molybdenum dithiocarbamate represented by the following formula (1), where the hydrocarbon groups in R1 to R4 are chain alkyl groups having 4 carbon atoms, MoDTC)

[0072]

[0073] (4) Organozinc compounds (D) • (D)-1: ZnDTP (a zinc dialkyldithiophosphate represented by formula (2) below, where the hydrocarbon groups in R19-22 are chain alkyl groups having 3 or 6 carbon atoms) • (D)-2: ZnDTC (zinc dithiocarbamate; zinc dithiocarbamate represented by formula (3) below: R39-42 are chain alkyl groups.)

[0074]

[0075]

[0076] (5) Additives: (X)-1: Thiadiazole, (X)-2: Sorbitan isostearate, (X)-3: Calcium dinonylnaphthalene sulfonate

[0077]

[0078]

[0079] [Evaluation of Load-Bearing Capacity] - High-Speed ​​Ball Test Following ASTM D2596, the maximum load that does not cause seizure when rotated at 1800 rpm for 10 seconds under a specified load (Last Non-Seizure Load: LNSL) was determined. The results obtained are shown in Tables 4 and 5. A higher maximum load value indicates better load-bearing capacity.

[0080] [Evaluation of wear resistance] A wear test was conducted using a high-speed four-ball tester under the following conditions, and the diameter of the wear marks (mm) after the test was measured. The results obtained are shown in Tables 4 and 5. Test piece: Steel ball for rolling bearings SUJ2 (1 / 2 inch) Grade 20 Test conditions: Rotation speed 1200 rpm, load 392 N, temperature 25 °C, test time 1 hour A lower value for the diameter of the wear marks indicates better wear resistance.

[0081]

[0082]

[0083] As shown in Tables 4 and 5, the grease compositions of the examples exhibit higher load-bearing capacity and wear resistance compared to the grease compositions of the comparative examples.

[0084] While preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments. Additions, omissions, substitutions, and other modifications are possible without departing from the spirit of the invention. The present invention is not limited by the foregoing description, but only by the scope of the appended claims.

Claims

1. The product contains a base oil (A), a thickener (B), an organic molybdenum compound (C), and an organic zinc compound (D), wherein the base oil (A) contains mineral oil (A1), the thickener (B) contains lithium complex soap (B1), and the base oil (A) has a kinematic viscosity of 100 mm at 40°C. ２ A grease composition having a coefficient of 1 / s or higher.

2. The base oil (A) has a kinematic viscosity of 200 mm at 40°C. ２ / s or more 250mm ２ The grease composition according to claim 1, wherein the ratio is less than or equal to / s.

3. The grease composition according to claim 1 or 2, for use in industrial machinery.

4. The grease composition according to claim 1 or 2, wherein the organic molybdenum compound (C) comprises a molybdenum dithiocarbamate.

5. The grease composition according to claim 1 or 2, wherein the organozinc compound (D) comprises one or more compounds selected from the group consisting of zinc dialkyldithiophosphate and zinc dithiocarbamate.

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