Non-fire-spreading grease composition

Abstract

The present invention provides a non-fire-spreading grease composition which contains: (a) as a thickening agent, a diurea compound that is represented by formula (1) R1-NHCONH-R2-NHCONH-R3 (wherein R2 represents an aromatic hydrocarbon group having 6 to 15 carbon atoms, R1 and R3 may be the same or different and each represent an aliphatic hydrocarbon group having 8 to 20 carbon atoms or an aromatic hydrocarbon group having 6 to 15 carbon atoms, and the proportion of the aliphatic hydrocarbon group in the total of R1 and R3 is 50-100 mol%); (b) a base oil that has a kinematic viscosity at 40°C of 300 mm2 / s or more; (c) at least one substance that is selected from the group consisting of rice wax, carnauba wax, and montanic acid derivatives; and (c) at least one substance that is selected from the group consisting of organic sulfonic acid metal salts, sodium sebacate, and glycerol.

Description

Non-fire-spreading grease composition

[0001] The present invention relates to a non-fire-spreading grease composition that can be used for bearings and gears in steelmaking equipment, etc. More specifically, the present invention relates to a non-fire-spreading grease composition that can be used in locations where there is a risk of fire caused by hot scale, etc., that peels off from the surface during steel processing and scatters, igniting and spreading the fire in the grease, or where water is used during rolling and processing of steel materials.

[0002] Grease is used to lubricate bearings and gears in steelmaking equipment, forging equipment, and other plastic processing equipment. Because bearings in steelmaking or rolling equipment in the steelmaking process process hot steel, the heat can cause grease to soften and leak from the bearings or deteriorate due to heat. To address these issues, heat-resistant greases are selected and grease is frequently replenished to bearings via centralized lubrication. Furthermore, because water cooling is required for steel processing in the rolling process, bearings are also exposed to water. Grease must be water-washable to prevent the grease sealed in the bearings from being washed away by water. Grease must also have water-containing shear stability, meaning it will not soften even when subjected to shear forces together with water within the bearings. Furthermore, fires caused by grease draining from bearings dripping and accumulating on the equipment, where scattered high-temperature scale can come into contact with the accumulated grease, igniting and spreading the fire, are a major concern. To prevent such fires, it is usually necessary to remove the drained grease. However, grease that has dripped into narrow spaces or that cannot be accessed during normal operations due to the processing of high-temperature steel can only be removed during scheduled maintenance when the equipment is shut down. Maintaining a constant state free of accumulated grease is difficult. Even if a fire breaks out, it is easy to extinguish it if it is discovered immediately. However, in highly automated facilities, the manpower is limited and fires are not always discovered immediately. Delayed detection of a fire can make extinguishing difficult, so greases are required to have fire-resistant properties to prevent the spread of fire. Conventional fire-resistant greases use high-viscosity mineral oil as the base oil, lithium soap as the thickener, and additives that are resistant to thermal decomposition (Non-Patent Document 1). However, lithium greases do not provide sufficient heat resistance for equipment exposed to high temperatures or for the piping that supplies grease to such equipment. Therefore, switching to urea greases, which have better heat resistance than lithium soap greases, is being considered. However, in urea grease, the thermal decomposition temperature of the thickener itself is lower than that of lithium soap, making it difficult to make non-flame-spreading grease even when blending base oils and additives that are difficult to evaporate.For example, Patent Document 1 discloses a urea grease for equipment that has load-bearing properties and non-flammability.

[0003] Lubrication Economy 2016 November Issue No. 619 46

[0004] Japanese Patent Application Laid-Open No. 2022-030575

[0005] An object of the present invention is to provide a non-fire-spreading grease composition that has excellent fire-spreading properties and water resistance. Another object of the present invention is to provide a bearing or gear that contains the non-fire-spreading grease composition.

[0006] 1. (a) A diurea compound represented by the following formula (1), R 1 -NHCONH-R 2 -NHCONH-R 3 (1) (wherein, R 2 represents an aromatic hydrocarbon group having 6 to 15 carbon atoms, and R 1 and R 3 may be the same or different and represent an aliphatic hydrocarbon group having 8 to 20 carbon atoms or an aromatic hydrocarbon group having 6 to 15 carbon atoms; R 1 and R 3 The proportion of aliphatic hydrocarbon groups in the total of (a) and (b) is 50 to 100 mol %. 2 / s or more, (c) at least one selected from the group consisting of rice wax, carnauba wax, and montanic acid derivatives, and (d) at least one selected from the group consisting of organic sulfonic acid metal salts, sodium sebacate, and glycerin. 2. The grease composition according to 1 above, wherein the content of (c) is 0.1 to 2.0 mass% relative to the total mass of the grease composition. 3. The grease composition according to 1 above, wherein the content of (d) is 0.1 to 1.0 mass% relative to the total mass of the grease composition. 4. The grease composition according to 1 above, wherein the organic sulfonic acid metal salt is a zinc salt or a calcium salt. 5. The grease composition according to 1 above, wherein the content of (a) is 2.5 to 8.0 mass% relative to the total mass of the grease composition. 6.0°C, shear rate 10 S -16. The grease composition according to 1 above, which has an apparent viscosity of 150 Pa·s or less at 100°C. 7. The grease composition according to 1 above, which is for centralized lubrication. 8. A bearing or gear in which the grease composition according to any one of 1 to 7 above is packed.

[0007] The urea grease composition of the present invention has excellent fire-resistance and water resistance. Particular embodiments of the present invention also have excellent pumpability through centralized lubrication. Without wishing to be bound by any theory, the reason why the grease composition of the present invention has fire-resistance is believed to be explained as follows. Specifically, even if a conventional urea grease contains a high-viscosity mineral oil with a high flash point as its base oil, it is believed to burn due to thermal decomposition of the thickener, the generated decomposition gas igniting and igniting the base oil. The addition of a compound having functional groups such as sulfonic acid groups, carboxyl groups, and hydroxyl groups, such as component (d) of the present invention, promotes the thermal decomposition of the urea thickener, thereby consuming the thickener decomposition gas, which causes continued combustion, in the early stages of combustion immediately after ignition. As the heat source temperature drops, the supply of decomposition gas decreases, thereby extinguishing the fire. However, compounds having functional groups such as sulfonic acid groups, carboxyl groups, and hydroxyl groups emulsify the grease in the presence of water, accelerating the softening of the grease by water. In particular, the thickener aliphatic urea softens when sheared in the presence of water. By adding component (c) of the present invention, component (c) protects the urea compound thickener, suppressing contact between the thickener and water, thereby improving water-containing shear stability. Component (c) is a polymeric compound and does not easily ignite.

[0008] [(a) Thickener] The thickener used in the present invention is a diurea compound represented by the following formula (1): R 1 -NHCONH-R 2 -NHCONH-R 3 (1) In the formula, R 2 represents an aromatic hydrocarbon group having 6 to 15 carbon atoms, and R 1 and R 3may be the same or different and represent an aliphatic hydrocarbon group having 8 to 20 carbon atoms or an aromatic hydrocarbon group having 6 to 15 carbon atoms; R 1 and R 3 The ratio of aliphatic hydrocarbon groups to the total of the above is 50 to 100 mol %. A diurea compound is a reaction product of a diisocyanate and a monoamine, and the thickener used in the present invention is an aliphatic urea compound in which the raw amine is an aliphatic amine, or an aromatic-aliphatic urea compound in which the raw amine is a mixture of an aromatic amine and an aliphatic amine (more specifically, a mixture of aromatic-aromatic urea, aromatic-aliphatic urea, and aliphatic-aliphatic urea, in other words, a mixture of diurea compounds represented by the following formulas (1-1), (1-2), and (1-3) R 1 -NHCONH-R 2 -NHCONH-R 3 (1-1) R 1 -NHCONH-R 2 -NHCONH-R 3 (1-2) R 3 -NHCONH-R 2 -NHCONH-R 3 (1-3) In the formula, R 1 ~R 3 is as defined above. An aromatic-aliphatic urea compound is more preferred. A diurea compound represented by formula (1), R 1 and R 3 may be the same or different and represent an aliphatic hydrocarbon group having 8 to 20 carbon atoms (preferably a linear alkyl group having 8 to 20 carbon atoms, more preferably a linear alkyl group having 8 or 18 carbon atoms) or an aromatic hydrocarbon group having 6 to 15 carbon atoms (preferably an aryl group having 6 or 7 carbon atoms); R 1 and R 3 Preferably, the diurea compound has an aliphatic hydrocarbon group ratio of 50 to 100 mol % based on the total of R 1 and R 3 It is more preferable that the diurea compound is a diurea compound in which the ratio of aliphatic hydrocarbon groups to the total of R 1 and R 3may be the same or different and represent a linear alkyl group having 8 carbon atoms or an aryl group having 6 carbon atoms, R 2 is a group derived from diphenylmethane-4,4'-diisocyanate, and R 1 and R 3 It is most preferred that the thickener is a diurea compound in which the proportion of linear alkyl groups having 8 carbon atoms in the total of the above is 80 mol %. The content of the thickener in the composition of the present invention may be any content that achieves the desired consistency depending on the application. For example, when the grease composition of the present invention is used as a grease for centralized lubrication, the content is preferably 2.0 to 9.0 mass %, more preferably 2.5 to 8.0 mass %, and even more preferably 3.0 to 8.0 mass %, based on the total mass of the composition. By setting the content within this range, non-flammability, pumpability, and water resistance can be more satisfactorily achieved. When the grease composition is not for centralized lubrication, the content is preferably 6.0 to 17.0 mass %, more preferably 6.0 to 12.0 mass %, and even more preferably 6.0 to 10.0 mass %. By setting the content within this range, water resistance and lubrication life of bearings can be further improved.

[0009] [(b) Base Oil] The base oil used in the present invention has a kinematic viscosity of 300 mm at 40°C. 2 The kinematic viscosity of the base oil of the present invention at 40°C is preferably 300 to 1000 mm 2 / s, more preferably 400 to 550 mm 2 / s. The kinematic viscosity at 40 ° C is 300 mm 2 / s or more, sufficient flame resistance can be achieved. Mineral oil, synthetic oil, or a mixture thereof can be used as the base oil. Examples of mineral oils include paraffinic mineral oil and naphthenic mineral oil. Examples of synthetic oils include ester-based synthetic oils such as diesters and polyol esters; synthetic hydrocarbon oils such as poly-α-olefins and polybutene; ether-based synthetic oils such as alkyl diphenyl ether and polypropylene glycol; silicone oil; and fluorinated oil. Synthetic oils may also be so-called biomass oils produced from biological resources derived from animals and plants. For example, biomass ester oils synthesized from various fatty acids and alcohols derived from vegetable oils, or biomass hydrocarbon oils derived from vegetable oils such as palm oil, corn oil, and soybean oil, can also be used. Among these, when the grease composition of the present invention is used as a grease for centralized lubrication, mineral oils are preferred from an economical standpoint. When not for centralized lubrication, synthetic hydrocarbon oils, ester oils, or ether oils are preferred from the standpoint of improving the lubrication life of bearings. When used as a grease for centralized lubrication, the base oil content in the grease composition of the present invention is preferably 75.0 to 97.0% by mass, and more preferably 82.0 to 96.0%. A base oil content within this range is preferred in terms of pumpability and non-fire spread. When not used for centralized lubrication, the base oil content in the grease composition of the present invention is preferably 70.0 to 93.0% by mass, and more preferably 75.0 to 93.0%. A base oil content within this range is preferred in terms of pumpability and non-fire spread.

[0010] [(c) Rice wax, carnauba wax, montanic acid derivatives] At least one selected from the group consisting of rice wax, carnauba wax, and montanic acid derivatives used in the present invention is classified as a wax. In this specification, wax refers to an organic substance having an alkyl group that is solid or semi-solid at room temperature (25°C), melts in a temperature range of approximately 35°C to 110°C (without dissolving in a base oil), and has a low melt viscosity. Rice wax refers to a wax obtained by refining wax oil separated during the refining of rice bran and rice bran oil, and has a CAS number of 8016-60-2. Rice wax is primarily composed of esters of fatty acids (C16 (approximately 5%), C22 (approximately 20%), C24 (approximately 60%), and the remainder being others) with alcohol. The rice wax preferably has an acid value of 10 mgKOH / g or less (e.g., 7 mgKOH / g or less, 5 mgKOH / g or less, or 3 mgKOH / g or less), a saponification value of 70 to 95 mgKOH / g, and a melting point of 77 to 83°C. A saponification value of 80 to 95 mgKOH / g is more preferable for improved flame resistance. Partially saponified rice wax (e.g., the CAS number for Ca partially saponified rice wax is 1850357-57-1) can also be used as the rice wax. The partially saponified rice wax preferably has an acid value of 6 to 15 mgKOH / g or less, a saponification value of 63 to 85 mgKOH / g, and a melting point of 96 to 107°C. The ratio of the fatty acids can be measured by gas chromatography. The acid value can be measured in accordance with ISO 2114. The saponification value can be measured according to ISO 3681. As the rice wax, it is preferable to use unsaponified rice wax.

[0011] Carnauba wax refers to wax extracted and refined from the leaves of the carnauba palm tree, and its CAS number is 8015-86-9. Carnauba wax is primarily composed of esters of fatty acids (C20 (approximately 7%), C22 (approximately 7%), C24 (approximately 25%), C26 (approximately 10%), C28 (approximately 15%), C30 (approximately 4%), C32 (approximately 6%), and the remainder being others) with alcohol. Carnauba wax preferably has an acid value of 12 mg KOH / g or less, a saponification value of 78 to 95 mg KOH / g, and a melting point of 80 to 86°C. The ratio of the fatty acids can be measured by gas chromatography. The acid value can be measured according to ISO 2114. The saponification value can be measured according to ISO 3681.

[0012] Montanic acid derivatives are waxes derived from Montanic acid and are classified as mineral oil-based waxes. They primarily contain long-chain esters and include free higher alcohols, resins, sulfur compounds, and other components. Examples of these include acid waxes with an acid value of 110 to 160 mgKOH / g, ester waxes with both non-polar and polar moieties, partially saponified ester waxes that are mixtures of Montanic acid ester compounds and saponified products with calcium hydroxide, saponified waxes of Montanic acid sodium salts and calcium salts, and Montan waxes to which ethylene oxide has been added. From the viewpoint of heat resistance, the dropping point is preferably 75°C or higher, more preferably 80°C or higher. From the viewpoint of solubility in base oil, the dropping point is preferably 105°C or lower. The acid value is preferably 0 to 160 mgKOH / g, more preferably 0 to 40 mgKOH / g. An acid value within this range is preferred because it minimizes the impact of oxidative degradation of the grease caused by the acid component. Commercially available products include LICOWAX OP FLAKES manufactured by Clariant Japan Co., Ltd.

[0013] Rice wax is preferred as component (c) of the present invention. Unsaponified rice wax is more preferred. Rice wax with a saponification value of 80 to 95 mgKOH / g is more preferred, and unsaponified rice wax is particularly preferred. Rice wax with an acid value of 2 to 3 mgKOH / g and a saponification value of 80 to 95 mgKOH / g is even more preferred, and unsaponified rice wax is particularly preferred. As described above, component (c) of the present invention protects the urea thickener from water in the grease, improves the grease's water-containing shear stability, and prevents the grease from softening. Rice wax is particularly preferred in terms of pumpability and water-containing shear stability. Two or more types may be used in combination. In this case, it is preferable to include rice wax, especially unsaponified rice wax. The contents of rice wax, carnauba wax, and montanic acid derivative are each 0.1 to 3.0% by mass, more preferably 0.1 to 2.0% by mass. In this range, pumpability, fire resistance, and water shear stability are more satisfactory. When two or more types are used in combination, it is preferable from the viewpoint of pumpability to set the total amount to 0.2 to 2.0 mass%.

[0014] [(d) Organic Sulfonate Metal Salt, Sodium Sebacate, Glycerin] As described above, the component (d) of the present invention promotes the thermal decomposition of the thickener urea, thereby suppressing the fire even if the grease catches fire. Among these, organic sulfonate metal salts are preferred. Examples of organic sulfonate metal salts used in the present invention include organic sulfonate metal salts such as sodium organic sulfonate, lithium organic sulfonate, barium organic sulfonate, zinc organic sulfonate, and calcium organic sulfonate. Zinc organic sulfonate and calcium organic sulfonate are preferred. As the organic sulfonic acid constituting the organic sulfonate metal salt, alkyl sulfonic acid and dinonylnaphthalene sulfonic acid are preferred, and dinonylnaphthalene sulfonic acid is preferred from the viewpoint of non-flammability. Therefore, as the organic sulfonate metal salt of the present invention, zinc alkyl sulfonate, calcium alkyl sulfonate, zinc dinonylnaphthalene sulfonate, and calcium dinonylnaphthalene sulfonate are particularly preferred. Zinc dinonylnaphthalene sulfonate is especially preferred.

[0015] When the composition of the present invention contains an organic metal sulfonate, the content thereof is preferably 0.1 to 3.0 mass %, more preferably 0.1 to 1.0 mass %, based on the total mass of the composition, in order to achieve more satisfactory flame resistance and water-containing shear stability.

[0016] When the composition of the present invention contains sodium sebacate, the content thereof is preferably 0.1 to 3.0 mass %, more preferably 0.1 to 1.0 mass %, based on the total mass of the composition, because within such a range, the non-flammability and water-containing shear stability are more satisfactory.

[0017] When the composition of the present invention contains glycerin, the content is preferably 0.1 to 5.0% by mass, more preferably 0.1 to 1.0% by mass, based on the total mass of the composition. Within these ranges, the fire resistance and hydrous shear stability are more satisfactory. Two or more types may be used in combination. In this case, it is preferable to use an organic sulfonate metal salt, particularly a zinc organic sulfonate or a calcium organic sulfonate, more particularly a zinc alkylsulfonate, a calcium alkylsulfonate, a zinc dinonylnaphthalenesulfonate, or a calcium dinonylnaphthalenesulfonate. When two or more types are used in combination, a total content of 0.2 to 1.0% by mass is preferred in terms of hydrous shear stability.

[0018] The ratio of component (c) to component (d) is not particularly limited, but for example, a mass ratio of (c):(d) of 3:10 to 5:1 is preferred from the viewpoint of water-containing shear stability, and a ratio of 2:1 to 4:1 is more preferred.

[0019] [Other Additives] The grease composition of the present invention may further contain conventional additives such as antioxidants, metal corrosion inhibitors, rust inhibitors, anti-wear agents, extreme pressure agents, solid lubricants, or oiliness agents. Examples of antioxidants include phenolic antioxidants and amine antioxidants. Examples of phenol-based antioxidants include 2,6-di-tert-butyl-p-cresol (BHT), 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 4,4'-butylidenebis(3-methyl-6-tert-butylphenol), 2,6-di-tert-butylphenol, 2,4-dimethyl-6-tert-butylphenol, tert-butylhydroxyanisole (BHA), 4,4'-butylidenebis(3-methyl-6-tert-butylphenol), 4,4'-methylenebis(2,3-di-tert-butylphenol), 4,4'-thiobis(3-methyl-6-tert-butylphenol), etc. Examples of amine-based antioxidants include N-n-butyl-p-aminophenol, 4,4'-tetramethyl-diaminodiphenylmethane, α-naphthylamine, N-phenyl-α-naphthylamine, phenothiazine, etc. Metal corrosion inhibitors include thiadiazoles, benzimidazoles, benzotriazoles, etc. Benzotriazoles include N,N-bis(2-ethylhexyl)-(4 or 5)-methyl-1H-benzotriazole 1-methylamine, etc. Rust inhibitors include succinic acid derivatives, etc. Succinic acid derivatives include alkenylsuccinic anhydrides, alkenylsuccinic acid esters, alkenylsuccinimides, etc.

[0020] Examples of anti-wear agents and extreme pressure agents include phosphorus-based compounds (tricresyl phosphate, tri-2-ethylhexyl phosphate, etc.), sulfur-based compounds (dibenzyl disulfide, various polysulfides, etc.), sulfur-phosphorus-based compounds (triphenyl phosphorothioate), organometallic extreme pressure agents (dialkyldithiophosphate salts of zinc, molybdenum, tin, bismuth, etc., dialkyldithiocarbamate salts of zinc, molybdenum, tin, nickel, copper, bismuth, etc.), and others (ashless dithiocarbamates). Examples of solid lubricants include organic molybdenum, molybdenum disulfide, graphite, polytetrafluoroethylene, and melamine cyanurate. Examples of oiliness agents include higher alcohols and ester oils. Examples of higher alcohols include stearyl alcohol. The content of such optional additives is, for example, 0.1 to 15.0 mass%, preferably 0.1 to 10.0 mass%, based on the total mass of the composition.

[0021] The grease composition of the present invention particularly includes: (a) a mixture of diurea compounds represented by the following formulas (1-1), (1-2), and (1-3) as a thickener; 1 -NHCONH-R 2 -NHCONH-R 3 (1-1) R 1 -NHCONH-R 2 -NHCONH-R 3 (1-2) R 3 -NHCONH-R 2 -NHCONH-R 3 (1-3) (wherein, R 2 represents a group derived from diphenylmethane-4,4'-diisocyanate, and R 1 is a linear alkyl group having 8 carbon atoms, and R 3 is an aryl group having 6 carbon atoms, and R 1 and R 3 The proportion of linear alkyl groups having 8 carbon atoms in the total of (a) and (b) is 80 mol %. 2A grease composition containing (a) a mineral oil having an acid value of 2 to 3 mgKOH / g and a saponification value of 80 to 95 mgKOH / g, (b) a rice wax having an acid value of 2 to 3 mgKOH / g and a saponification value of 80 to 95 mgKOH / g, and (c) zinc dinonylnaphthalenesulfonate is particularly preferred. In particular, a grease composition in which the content of (c) is 0.1 to 2.0 mass% relative to the total mass of the grease composition and / or the content of (d) is 0.1 to 1.0 mass% relative to the total mass of the grease composition is preferred.

[0022] [Consistency] The consistency of the grease composition of the present invention is adjusted according to the intended use, but is preferably 220 to 430, more preferably 280 to 430. When the grease composition of the present invention is used as a grease for centralized lubrication of bearings in steel and forging equipment, a consistency of 310 to 385 is preferred from the viewpoints of facilitating pressure-feeding of the grease and preventing grease leakage. When the grease composition of the present invention is used for purposes other than centralized lubrication, a consistency of 265 to 385, more preferably 285 to 365, is preferred from the viewpoints of improving water resistance and the lubrication life of the bearings. In this specification, the term "consistency" refers to 60-stroke worked consistency. The consistency can be measured in accordance with JIS K2220 7.

[0023] The composition of the present invention is -1 It is preferable that the apparent viscosity at 150 Pa s or less is used. This allows the grease to be pumped smoothly regardless of the outside temperature, especially during cold weather when the fluidity of the grease tends to decrease. The apparent viscosity can be adjusted by the kinematic viscosity of the base oil and / or the amount of thickener.

[0024] The non-fire-spreading grease composition of the present invention can be produced by reacting an amine and an isocyanate in a base oil, followed by heating and dispersing the mixture. Furthermore, additives can be added during the production process. The non-fire-spreading grease composition of the present invention can be enclosed in bearings or gears for use. It is particularly suitable for use as a grease composition for centralized lubrication, and is particularly suitable for use as a grease composition for steelmaking equipment. Furthermore, it is preferable to enclose the non-fire-spreading grease composition in bearings or gears for use in steelmaking equipment.

[0025] The components used to prepare the test greases are as follows: (b) Base oil: Mineral oil: Kinematic viscosity at 40°C: 460 mm 2 / s Mineral oil: kinematic viscosity at 40 ° C: 300 mm 2 / s Mineral oil: kinematic viscosity at 40 ° C: 132 mm 2 / s

[0026] (c) Additives Rice wax A: TOWAX 3F17 (Toa Kasei Co., Ltd.) Acid value 5.4 mg KOH / g, saponification value 77.3 mg KOH / g, melting point 80.1°C Rice wax B: Rice wax A-1 (Cerarica NODA Co., Ltd.) Acid value 2.6 mg KOH / g, saponification value 81.1 mg KOH / g, melting point 79.1°C Ca partially saponified rice wax: LICOCARE RBW300 (Clariant Japan Co., Ltd.) Acid value 11.0 mg KOH / g, saponification value 75.0 mg KOH / g, melting point 102°C Carnauba wax: Carnauba WAX2 (Toa Kasei Co., Ltd.) Acid value 11.6 mg KOH / g, saponification value 91.2 mg KOH / g, melting point 82.3°C Montanic acid derivative: LICOWAX OP FLAKES (Clariant Japan Co., Ltd.) Acid value 12 mg KOH / g, saponification value 112 mg KOH / g, melting point 100°C Lanolin wax: Industrial lanolin TSC (Nippon Fine Chemical Co., Ltd.) Acid value 125 mg KOH / g, saponification value 175 mg KOH / g, melting point 60°C Oxidized polyethylene wax: LICOWAX PED522 (Clariant Japan Co., Ltd.) Acid value 25 mg KOH / g, melting point 101°C

[0027] (d) Additives Organic sulfonic acid metal salts Calcium alkylsulfonate: Sulfol Ca-45 (Moresco Corporation) Zinc dinonylnaphthalenesulfonate: NA-SUL ZS (King Industries) Calcium dinonylnaphthalenesulfonate: NA-SUL 729 (King Industries) Sodium sebacate: Irgacor DSSG (BASF Japan Ltd.) Glycerin: Seisei Glycerin V (Kao Corporation)

[0028] [Urea Grease] 1 mole of diphenylmethane-4,4'-diisocyanate was reacted with 2 moles of aniline and octylamine in a base oil, and the mixture was heated. During cooling, at least one selected from the group consisting of rice wax, carnauba wax, and montanic acid derivatives was added in the proportions shown in the table below to obtain a base grease. Additives and additional base oil were added to the base grease in the proportions shown in the table to obtain the desired thickener amount, and the mixture was dispersed using a three-roll mill to obtain grease compositions of the examples and comparative examples. The respective blending ratios are as shown in the table below. The numbers in the table indicate the molar ratio of the aromatic amine (aniline) to the aliphatic amine (octylamine) for the thickener; all other values ​​indicate mass % based on the total mass of the composition. The kinematic viscosity of the base oil at 40°C was measured in accordance with JIS K2220 23. The grease compositions obtained above were tested using the methods described below. The results are shown in the table below.

[0029] [Lithium soap grease] 12OH stearic acid was dissolved in base oil by heating, and lithium hydroxide dissolved in warm water was added and reacted. The grease was heated until the water in the grease was removed, and then cooled to obtain a base grease. Additives were blended into the base grease, and additional base oil was added to achieve the desired thickener amount. Additives were added and dispersed using a three-roll mill to prepare a grease composition.

[0030] <Test Method> ○ Water-containing roll stability test (based on ASTM D 1831) This test involves applying shear to a grease composition in an environment containing moisture. This test was used to evaluate the water-containing shear stability (water resistance) of the grease composition. [Test conditions] - Amount of grease filled: 45 g - Ion-exchanged water: 5 g - Rotation speed: 165 rpm - Test temperature: 80°C - Test time: 24 hours [Evaluation] ◎: Worked penetration after test: 400 or less ○: Worked penetration after test: 401 to 415 △: Worked penetration after test: 416 to 439 or less ×: Worked penetration after test: 440 or more (liquefaction)

[0031] ◯ Evaluation of non-flame spread property 100 g of the grease composition was placed in a metal container (stainless steel tray) measuring 155 mm wide x 126 mm long x 27 mm deep, and a steel ball (diameter 26.98 mm) heated to a specified temperature (950°C) was placed in the container to ignite and burn, and the time from ignition to extinguishing of the flame was measured as the burning time. If the burning time exceeded 300 seconds, it was determined that there was no non-flame spread property, and the fire was extinguished and the test was stopped. [Evaluation] ◎: Burning time was within 150 seconds ◯: Burning time was more than 150 seconds but not more than 180 seconds △: Burning time was more than 180 seconds but not more than 300 seconds ×: Continuous burning was more than 300 seconds

[0032] Pumpability evaluation (JIS K 2220 19.) This test is conducted at 0°C and a shear rate of 10S. -1 This is a test to evaluate the pumpability of a grease composition by measuring the apparent viscosity of the grease composition in the following manner. [Evaluation] ◎: Apparent viscosity is 120 Pa·s or less ○: Apparent viscosity is more than 120 to 150 Pa·s or less ×: Apparent viscosity is more than 150 Pa·s

[0033]

[0034]

[0035]

[0036]

Claims

1. (a) A diurea compound represented by the following formula (1), R 1 -NHCONH-R 2 -NHCONH-R 3 (1) (wherein, R 2 represents an aromatic hydrocarbon group having 6 to 15 carbon atoms, and R 1 and R 3 may be the same or different and represent an aliphatic hydrocarbon group having 8 to 20 carbon atoms or an aromatic hydrocarbon group having 6 to 15 carbon atoms; R 1 and R 3 The proportion of aliphatic hydrocarbon groups in the total of (a) and (b) is 50 to 100 mol %. 2 (c) at least one member selected from the group consisting of rice wax, carnauba wax, and montanic acid derivatives; and (d) at least one member selected from the group consisting of organic metal sulfonates, sodium sebacate, and glycerin.

2. A grease composition according to claim 1, wherein the content of (c) is 0.1 to 2.0 mass % based on the total mass of the grease composition.

3. A grease composition according to claim 1, wherein the content of (d) is 0.1 to 1.0 mass % based on the total mass of the grease composition.

4. The grease composition according to claim 1, wherein the metal salt of organic sulfonic acid is a zinc salt or a calcium salt.

5. A grease composition according to claim 1, wherein the content of (a) is 2.5 to 8.0 mass % based on the total mass of the grease composition.

6. 0℃, shear rate 10S -1 2. The grease composition according to claim 1, having an apparent viscosity of 150 Pa·s or less at 1000 kJ / min.

7. The grease composition according to claim 1, which is for centralized lubrication.

8. A bearing or gear in which the grease composition according to any one of claims 1 to 7 is packed.

Images