Method for producing grease composition

Abstract

This method for producing a grease composition includes a reaction and mixing step for reacting and simultaneously mixing and dispersing a mixed solution A containing a thickener raw material A and a solvent A and a mixed solution B containing a thickener raw material B and a solvent B by means of a vibratory stirrer. In the reaction and mixing step, the mixed solution A and the mixed solution B are continuously supplied to the vibratory stirrer, and a spiral stirring blade provided in a container of the vibratory stirrer reciprocates in a direction along an axis of the stirring blade, thereby reacting and mixing the mixed solution A and the mixed solution B.

Description

Method for producing a grease composition 【0001】 The present invention relates to a method for producing a grease composition. This application claims priority based on Japanese Patent Application No. 2024-216404, filed in Japan on December 11, 2024, and incorporates its content herein by reference. 【0002】 Grease is a lubricant made by dispersing a solid thickener with strong lipophilicity in a base oil to make it semi-solid. Grease is more likely to adhere to the lubricated part and less likely to flow out compared to lubricating oil. Therefore, by using grease, the mechanical structure of the lubrication system can be simplified. In addition, grease has less leakage than lubricating oil, can achieve a clean environment, and can reduce the replenishment interval compared to lubricating oil. Grease is mainly used for lubricating mechanical elements such as rolling bearings, sliding bearings, ball screws, linear guides, and gears. Rolling bearings are widely used in the main shafts of machine tools, railway vehicle bodies, engine accessories such as alternators in automobiles, constant velocity joints, and wheels, etc. 【0003】 Grease is usually produced in batches. After mixing the base oil and the thickener, or reacting the thickener raw material in the base oil to obtain a mixture, the mixture is crushed by a mill processor to uniformly disperse the thickener. However, in conventional batch production, there are problems such as large fluctuations when changing from small-lot scale to large-lot scale and a large burden of cleaning during product switching. In addition, in the mill processor, there is a problem that coarse thickener particles remain and are not uniformly dispersed. 【0004】 In contrast, for example, Patent Document 1 discloses mixing base oil 1 containing thickener precursor 1 and base oil 2 containing thickener precursor 2 to form a mixed liquid, and applying a shear rate of 10 ２ s －１ or more to react while mixing and dispersing thickener precursor 1 and thickener precursor 2 to form a thickener. According to this method for producing grease, it is disclosed that large micelle particles (large lumps) composed of the thickener are unlikely to be generated. 【0005】Japanese Patent Publication No. 2015-030838 【0006】 In recent years, with the increasing demand for quieter automotive parts and improved cabin quietness, there is a need to reduce unwanted noises emitted from automotive parts that were not previously considered a problem in vehicles. Similarly, quiet operation is also a requirement for home appliances. It is known that acoustic properties can be improved by appropriately controlling the size of thickener particles in grease compositions. 【0007】 In conventional methods for producing grease compositions, such as those described in Patent Document 1, there is room for improvement in the dispersibility of the thickener in the grease composition. Furthermore, stable production may not be possible due to the effects of shear heat. 【0008】 The present invention has been made in view of the above circumstances, and aims to provide a method for producing a grease composition that can produce a grease composition with good acoustic properties. 【0009】To solve the above problems, the present invention employs the following configurations: [1] A method for producing a grease composition, comprising a reaction mixing step of reacting and mixing a mixed solution A containing a thickener raw material A and a solvent A with a mixed solution B containing a thickener raw material B and a solvent B using a vibrating stirrer, wherein the reaction mixing step is characterized in that the mixed solution A and the mixed solution B are continuously supplied to the vibrating stirrer, and a spiral stirring blade provided in the container of the vibrating stirrer reciprocates in a direction along the axis of the stirring blade to react and mix the mixed solution A and the mixed solution B. [2] A method for producing a grease composition, comprising a mixing step of mixing a mixed solution containing a thickener and a solvent using a vibrating stirrer, wherein the mixing step is characterized in that the mixed solution is continuously supplied to the vibrating stirrer, and a spiral stirring blade provided in the container of the vibrating stirrer reciprocates in a direction along the axis of the stirring blade to mix the mixed solution.[3] A method for producing a grease composition, comprising: mixing step A to produce an alkali metal soap solution A or alkaline earth metal soap solution A by mixing a mixed solution A1 containing solvent A1 and fatty acid A1 with a mixed solution A2 containing solvent A2 and alkali metal hydroxide or alkaline earth metal hydroxide; mixing step B to produce an alkali metal soap solution B or alkaline earth metal soap solution B by mixing a mixed solution B1 containing solvent B1 and fatty acid B1 with a mixed solution B2 containing solvent B2 and the alkali metal hydroxide or alkaline earth metal hydroxide; and mixing step C to produce an alkali metal complex soap or alkaline earth metal complex soap by mixing the alkali metal soap solution A or alkaline earth metal soap solution A with the alkali metal soap solution B or alkaline earth metal soap solution B. Mixing step A involves continuously supplying the mixed solution A1 and the mixed solution A2 to a vibrating agitator, and mixing the mixed solution A1 and the mixed solution A2 by causing a spiral stirring blade provided in the container of the vibrating agitator to reciprocate in a direction along the axis of the stirring blade. Mixing step B involves continuously supplying the mixed solution B1 and the mixed solution B2 to a vibrating agitator, and mixing the mixed solution B1 and the mixed solution B2 by causing a spiral stirring blade provided in the container of the vibrating agitator to reciprocate in a direction along the axis of the stirring blade. The mixing step C is a method for producing a grease composition, wherein the alkali metal soap solution A or the alkaline earth metal soap solution A and the alkali metal soap solution B or the alkaline earth metal soap solution B are continuously supplied to a vibrating agitator, and a spiral stirring blade provided in the container of the vibrating agitator moves back and forth in a direction along the axis of the stirring blade, thereby mixing the alkali metal soap solution A or the alkaline earth metal soap solution A and the alkali metal soap solution B or the alkaline earth metal soap solution B.[4] A method for producing a grease composition, comprising a mixing step of mixing a mixed solution A containing solvent A, fatty acid A, and fatty acid B, and a mixed solution B containing solvent B and alkali metal hydroxide or alkaline earth metal hydroxide to produce alkali metal complex soap or alkaline earth metal complex soap, wherein the mixing step is characterized in that the mixed solution A and the mixed solution B are continuously supplied to a vibrating agitator, and a spiral stirring blade provided in the container of the vibrating agitator reciprocates in a direction along the axis of the stirring blade to cause the mixed solution A and the mixed solution B to react and mix. 【0010】 According to the present invention, a method for producing a grease composition with good acoustic properties can be provided. 【0011】 This is a schematic diagram of a vibrating agitator used in the manufacturing method of the first grease composition. This is a schematic diagram of a vibrating agitator used in the manufacturing method of the second grease composition. 【0012】(Method for Manufacturing Grease Composition) The method for manufacturing the grease composition of this embodiment includes a mixing step in which the base oil and the thickener or thickener raw material are mixed using a vibrating stirrer. Here, whether the base oil and the thickener raw material are mixed, or the base oil and the thickener are mixed, depends on the type of thickener used. For example, when using a urea-based thickener (B1), a metal soap-based thickener (B2), etc., the thickener is produced by the chemical reaction of multiple thickener raw materials in the mixing step. Therefore, multiple thickener raw materials are reacted in the base oil using a vibrating stirrer and simultaneously mixed and dispersed. On the other hand, when using an inorganic thickener such as bentonite and silica gel (B3), the base oil and the thickener are mixed using a vibrating stirrer in the mixing step. A method for producing a grease composition having a reaction mixing step in which multiple thickening agent raw materials are reacted and mixed and dispersed in a base oil using a vibrating stirrer is referred to as the "first method for producing a grease composition," and a method for producing a grease composition having a mixing step in which a base oil and a thickening agent are mixed using a vibrating stirrer is referred to as the "second method for producing a grease composition," and these methods are described below. 【0013】 <Method for Producing the First Grease Composition> The method for producing the first grease composition is a method for producing a grease composition comprising a reaction mixing step in which a mixed solution A containing a thickening agent raw material A and a solvent A and a mixed solution B containing a thickening agent raw material B and a solvent B are reacted and mixed simultaneously in a vibrating stirrer, wherein the reaction mixing step is a method for producing a grease composition in which the mixed solution A and the mixed solution B are continuously supplied to the vibrating stirrer, and a spiral stirring blade provided in the container of the vibrating stirrer reciprocates in a direction along the axis of the stirring blade, thereby reacting and mixing the mixed solution A and the mixed solution B. 【0014】[Reaction and Mixing Process] The reaction and mixing process involves reacting and simultaneously mixing and dispersing a mixed solution A containing thickener raw material A and solvent A, and a mixed solution B containing thickener raw material B and solvent B, using a vibrating stirrer. In the reaction and mixing process, the mixed solution A and the mixed solution B are continuously supplied to the vibrating stirrer, and a spiral stirring blade provided in the container of the vibrating stirrer reciprocates in a direction along the axis of the stirring blade, thereby causing the mixed solution A and the mixed solution B to react and mix. 【0015】 Thickening agent raw material A, thickening agent raw material B, solvent A, and solvent B may each be a single type or two or more types. 【0016】 <(1) Thickener raw materials A and B> For example, when producing a urea-based thickener (B1), thickener raw materials A and B are a diisocyanate and a monoamine or diamine. Examples of urea-based thickeners (B1) include diurea compounds and polyurea compounds. A diurea compound is a compound obtained by the reaction of a diisocyanate and a monoamine, and is a compound having two urea groups (-NH-CO-NH-). In this specification, a polyurea compound is a compound obtained by the reaction of a diisocyanate and a monoamine or diamine, and is a compound having three or more urea groups (-NH-CO-NH-). 【0017】 Diisocyanates are compounds in which two hydrogen atoms of a hydrocarbon are replaced by isocyanate groups (-N=C=O). The hydrocarbon may be a cyclic hydrocarbon or a chain hydrocarbon. The hydrocarbon may also be an aromatic hydrocarbon or an aliphatic hydrocarbon. The number of carbon atoms in the hydrocarbon is preferably 4 to 20, and more preferably 8 to 18. In this invention, "number of carbon atoms 4 to 20" means having 4 to 20 carbon atoms. 【0018】Preferred examples of diisocyanates include phenylene diisocyanate, tolylene diisocyanate, biphenyl diisocyanate (diphenyl diisocyanate), diphenylmethane-4,4'-diisocyanate (MDI), octadecane diisocyanate, decanediisocyanate, and hexane diisocyanate. Diisocyanates may be used individually or in combination of two or more types. 【0019】 Monoamines are compounds that have one amino group in one molecule. Preferred monoamines include octylamine, dodecylamine, hexadecylamine, stearylamine (octadecylamine), oleylamine, aniline, p-toluidine, and cyclohexylamine. Monoamines may be cyclic or linear. They may also be alicyclic, aromatic, or aliphatic amines. The monoamine has 4 to 20 carbon atoms, and more preferably 8 to 18. 【0020】 Diamines are compounds having two amino groups in one molecule. Preferred diamines include ethylenediamine, propanediamine, butanediamine, hexanediamine, octanediamine, phenylenediamine, tolylenediamine, xylenediamine, and diaminodiphenylmethane. Diamines may be cyclic or linear. Diamines may also be alicyclic, aromatic, or aliphatic amines. The number of carbon atoms in the diamine is preferably 4 to 20, and more preferably 8 to 18. 【0021】≪(2) Thickener Raw Materials A and B≫ For example, when manufacturing a metal soap-based thickener (B2), thickener raw materials A and B consist of fatty acids or oils and fats, and alkali metal hydroxides or alkaline earth metal hydroxides. Examples of metal soap-based thickeners (B2) include single soaps and complex soaps. A single soap is a metal soap made by saponifying fatty acids or oils with alkali metal hydroxides or alkaline earth metal hydroxides, etc. A complex soap is made by combining the fatty acids used in single soaps with organic acids of different molecular structures. 【0022】 The fatty acid may be a fatty acid derivative having a hydroxyl group, etc. A monovalent or divalent aliphatic carboxylic acid is preferred as the fatty acid. A fatty acid having 6 to 20 carbon atoms is preferred, and a monovalent aliphatic carboxylic acid having 12 to 20 carbon atoms or a divalent aliphatic carboxylic acid having 6 to 14 carbon atoms is more preferred. Among the above, a monovalent aliphatic carboxylic acid containing one hydroxyl group is preferred as the fatty acid. As organic acids to be combined with the fatty acid in the complex soap, dibasic acids such as acetic acid, azelaic acid, or sebacic acid, or benzoic acid are preferred. 【0023】 As metal soap thickeners, alkali metals such as lithium and sodium, alkaline earth metals such as calcium, or amphoteric metals such as aluminum are used. 【0024】 <<Solvents A and B>> Examples of solvents A and B include water, synthetic oil, mineral oil, etc. 【0025】 <<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. Among the above, polyolefins are preferred as synthetic oils from the viewpoint of availability, cost, viscosity characteristics, and oxidation stability, and poly-α-olefins (PAO) are more preferred. 【0026】≪Mineral Oil≫ As mineral oil, 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 combining 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. 【0027】 <Optional Components> Mixed solutions A and B may contain optional components other than the thickener, thickener raw material, and solvent mentioned above. Examples of such optional components include solid lubricants, anti-wear agents or extreme pressure agents, antioxidants, oiliness agents, rust inhibitors, and corrosion inhibitors. 【0028】 Examples of solid lubricants include graphite, graphite fluoride, melamine cyanurate, polytetrafluoroethylene, molybdenum disulfide, antimony sulfide, boron nitride, and alkali (earth) metal borates. 【0029】 Examples of anti-wear or extreme pressure agents include organozinc compounds such as zinc dialkyldithiophosphate and zinc dialkyldithiocarbamate; sulfur-containing compounds such as molybdenum dialkyldithiocarbamate, 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. 【0030】 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. 【0031】Examples of oily agents include amines such as laurylamine, myristylamine, palmitylamine, stearylamine, and oleylamine; higher alcohols such as lauryl alcohol, myristyl alcohol, palmityl alcohol, stearyl alcohol, and oleyl alcohol; higher fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, and oleic acid; fatty acid esters such as methyl laurate, methyl myristate, methyl palmitate, methyl stearate, and methyl oleate; and oils and fats such as glycerin oleate and glycerin stearate. 【0032】 Examples of rust inhibitors include amines, neutral or overbasic petroleum-based or synthetic oil-based metal sulfonates, carboxylate metal salts, esters, phosphoric acid, and phosphates. 【0033】 As corrosion inhibitors, known corrosion inhibitors such as benzotriazole compounds, toltriazole compounds, thiadiazole compounds, and imidazole compounds can be used. 【0034】 [Flow Rate] For example, the flow rate when supplying solvents A and B to the vibrating stirrer is preferably 100 mL / min or more and 8000 mL / min or less. 【0035】 [Vibration Frequency] The vibration frequency of the helical stirring blade (the frequency of vibration when reciprocating along the axis of the stirring blade) is preferably 10 Hz or higher, more preferably 15 Hz or higher, and even more preferably 20 Hz or higher. The vibration frequency of the helical stirring blade is preferably 40 Hz or lower, more preferably 35 Hz or lower, and even more preferably 30 Hz or lower. If the vibration frequency of the helical stirring blade is above the above preferred lower limit, mixing and dispersion will be better, and the thickener particles will be more easily refined. If the vibration frequency of the helical stirring blade is below the above preferred upper limit, heat generation can be better prevented. For example, the vibration frequency of the helical stirring blade is preferably 10 Hz or higher and 40 Hz or lower, more preferably 15 Hz or higher and 35 Hz or lower, and even more preferably 25 Hz or higher and 30 Hz or lower. 【0036】[Temperature] For example, the temperature in the mixing process is preferably 60°C to 200°C. 【0037】 In addition to the above-mentioned control, control can be appropriately performed to further refine the thickener in the grease composition. Other control methods include the amplitude of vibration of the helical stirring blade (the amplitude when the blade moves back and forth along its axis). 【0038】 [Vibrating Agitator] The vibrating agitator used in the method for manufacturing the first grease composition will be described in detail with reference to the figures. Figure 1 shows a schematic diagram of the vibrating agitator used in the method for manufacturing the first grease composition. The vibrating agitator 1 comprises a cylindrical container 9 with its upper and lower end faces closed, an inlet A3 for mixed solution A provided on one of the lower end faces of the container 9, an inlet B5 for mixed solution B provided on the other lower end face of the container 9, an outlet 7 provided on the upper end face of the container 9, and a flow passage 6 through which mixed solution A and mixed solution B flow inside the container 9. 【0039】 The flow passage 6 is equipped with spiral stirring blades 11 that reciprocate in the flow direction of mixed solution A and mixed solution B. Furthermore, spiral partitions 8 are provided inside the flow passage 6. The spiral stirring blades 11 reciprocate between the partitions 8 in a direction along the axis of the spiral stirring blades 11. 【0040】 Mixed solution A is supplied to container 9 from tank 13, where it is stored, via pump 17. Mixed solution B is also supplied to container 9 from tank 15, where it is stored, via pump 19. 【0041】 The spiral stirring blade 11 moves back and forth in the flow direction of mixed solution A and mixed solution B. This mixes mixed solution A and mixed solution B. A grease composition is produced by mixing mixed solution A and mixed solution B. The produced grease composition is discharged from the outlet 7. 【0042】Similar to the "Method for Manufacturing the First Grease Composition" described above, in a method for manufacturing a grease composition having a reaction mixing step in which multiple thickening agent raw materials are reacted and mixed simultaneously in a base oil using a vibrating stirrer, if the thickening agent to be manufactured is a "complex soap", then either the "Method for Manufacturing the First Grease Composition A" or the "Method for Manufacturing the First Grease Composition B" described below may be used. The "Method for Manufacturing the First Grease Composition B" is a manufacturing method that is a sub-concept of the "Method for Manufacturing the First Grease Composition". The "Method for Manufacturing the First Grease Composition A" is a method for manufacturing a grease composition in which multiple thickening agent raw materials are reacted and mixed simultaneously in a base oil using a vibrating stirrer to produce a single soap, then multiple thickening agent raw materials are reacted and mixed simultaneously in a base oil using a vibrating stirrer to produce another single soap, and finally, the single soap and the other single soaps are reacted and mixed simultaneously in a vibrating stirrer to produce a complex soap. 【0043】<<Manufacturing Method of First A Grease Composition>>The manufacturing method of the first A grease composition includes a mixing step A of mixing a mixed solution A1 containing a solvent A1 and a fatty acid A1 with a mixed solution A2 containing a solvent A2 and an alkali metal hydroxide or an alkaline earth metal hydroxide to produce an alkali metal soap solution A or an alkaline earth metal soap solution A, a mixing step B of mixing a mixed solution B1 containing a solvent B1 and a fatty acid B1 with a mixed solution B2 containing a solvent B2 and the alkali metal hydroxide or the alkaline earth metal hydroxide to produce an alkali metal soap solution B or an alkaline earth metal soap solution B, and a mixing step C of mixing the alkali metal soap solution A or the alkaline earth metal soap solution A with the alkali metal soap solution B or the alkaline earth metal soap solution B to produce an alkali metal complex soap or an alkaline earth metal complex soap. The mixing step A is such that the mixed solution A1 and the mixed solution A2 are continuously supplied to a vibration stirrer, and a spiral stirring blade provided in the container of the vibration stirrer reciprocates in a direction along the axis of the stirring blade to mix the mixed solution A1 and the mixed solution A2. The mixing step B is such that the mixed solution B1 and the mixed solution B2 are continuously supplied to a vibration stirrer, and a spiral stirring blade provided in the container of the vibration stirrer reciprocates in a direction along the axis of the stirring blade to mix the mixed solution B1 and the mixed solution B2. The mixing step C is such that the alkali metal soap solution A or the alkaline earth metal soap solution A and the alkali metal soap solution B or the alkaline earth metal soap solution B are continuously supplied to a vibration stirrer, and a spiral stirring blade provided in the container of the vibration stirrer reciprocates in a direction along the axis of the stirring blade to mix the alkali metal soap solution A or the alkaline earth metal soap solution A and the alkali metal soap solution B or the alkaline earth metal soap solution B. It is a manufacturing method of a grease composition. 【0044】<<Manufacturing Method of First B Grease Composition>>The manufacturing method of the first B grease composition is a manufacturing method of a grease composition having a mixing step of mixing a mixed solution A containing a solvent A, a fatty acid A, and a fatty acid B with a mixed solution B containing a solvent B and an alkali metal hydroxide or an alkaline earth metal hydroxide to produce an alkali metal complex soap or an alkaline earth metal complex soap. In the mixing step, the mixed solution A and the mixed solution B are continuously supplied to a vibration stirrer, and a spiral stirring blade provided in the container of the vibration stirrer reciprocates in a direction along the axis of the stirring blade, thereby causing the mixed solution A and the mixed solution B to react and mix. This is a manufacturing method of a grease composition. 【0045】 The solvents, fatty acids, alkali metal hydroxides, alkaline earth metal hydroxides, etc. in the manufacturing methods of the first A and B grease compositions are the same as those of the solvents, fatty acids, alkali metal hydroxides, alkaline earth metal hydroxides, etc. in the manufacturing method of the first grease composition described above. 【0046】 <Manufacturing Method of Second Grease Composition>The manufacturing method of the second grease composition is a manufacturing method of a grease composition having a mixing step of mixing a mixed solution containing a thickener and a solvent with a vibration stirrer. In the mixing step, the mixed solution is continuously supplied to a vibration stirrer, and a spiral stirring blade provided in the container of the vibration stirrer reciprocates in a direction along the axis of the stirring blade, thereby causing the mixed solution to mix. This is a manufacturing method of a grease composition. In the mixing step, the mixed solution is continuously supplied to a vibration stirrer, and a spiral stirring blade provided in the container of the vibration stirrer reciprocates in a direction along the axis of the stirring blade, thereby causing the mixed solution to mix. 【0047】 [Mixing Step] The mixing step is a step of mixing a mixed solution containing a thickener and a solvent with a vibration stirrer. 【0048】 <<Thickener>> Examples of the thickener include inorganic thickeners such as bentonite and silica gel. 【0049】<Solvents> Examples include water, synthetic oils, and mineral oils as mentioned above. 【0050】 ≪Optional Components≫ The mixed solution in this embodiment may also contain the optional components described above. 【0051】 In the method for producing the second grease composition, the preferred flow rate, vibration frequency, and temperature in the mixing step are the same as those in the reaction mixing step in the method for producing the first grease composition described above. 【0052】 [Vibrating Agitator] The vibrating agitator used in the method for manufacturing the second grease composition will be described in detail with reference to the figures. Figure 2 shows a schematic diagram of the vibrating agitator used in the method for manufacturing the second grease composition. The vibrating agitator 2 comprises a cylindrical container 29 with its upper and lower end faces closed, an inlet 23 for the mixed solution provided on one of the lower end faces of the container 29, an outlet 27 provided on the upper end face of the container 29, and a flow passage 26 through which the mixed solution flows inside the container 29. 【0053】 The flow passage 26 is equipped with spiral stirring blades 22 that reciprocate in the direction of flow of the mixed solution. A partition 28 is also provided inside the flow passage 26. 【0054】 The mixed solution is supplied from the tank 25, where it is stored, to the container 29 via the pump 21. 【0055】 The spiral agitator blades 22 reciprocate in the direction of the flow of the mixed solution. This mixes the mixed solution. The mixing of the mixed solution produces a grease composition. The produced grease composition is discharged from the outlet 27. 【0056】 Examples of commercially available vibrating agitators include the VIBROMIXER manufactured by Reika Co., Ltd. 【0057】Grease composition A was produced by mixing the following raw materials using a vibrating stirrer with the configuration shown in Figure 1. Thickening agent raw material A: Diphenylmethane-4,4'-diisocyanate (4.0% by mass) Solvent A: Poly-α-olefin (46.4% by mass) Thickening agent raw material B: Stearylamine (octadecylamine), cyclohexylamine (5.9% by mass) Solvent B: Poly-α-olefin (43.7% by mass) 【0058】 Observation of the thickener in grease composition A using an optical microscope revealed that the diameter of the thickener particles in the grease composition was small and that it was uniformly dispersed. Therefore, it was confirmed that the manufacturing method of the grease composition according to this embodiment allows for better dispersion of the thickener in the grease composition. 【0059】 (Examples 1-3, Comparative Example 1) Grease compositions with the same composition as grease composition A were manufactured by changing the manufacturing conditions (vibration frequency). The manufacturing method for the grease composition of Comparative Example 1 was the same as the conventional method for manufacturing grease compositions, in which the raw materials were mixed in a mixer. The manufacturing conditions for the manufacturing methods of the grease compositions in each example are shown in Table 1. 【0060】 [Consistency Evaluation] Table 1 shows the mixed consistency of each example of grease composition, measured in accordance with JIS K2220:2013. 【0061】 [Evaluation of Acoustic Characteristics] A bearing vibration measuring instrument (manufactured by Sugawara Research Institute Co., Ltd., product name: Anderon Meter) was used to evaluate the acoustic characteristics. Specifically, a 608 bearing filled with each example grease composition was set up and rotated for 30 seconds at an axial load of 30 N and a rotational speed of 1800 rpm. The radial vibration of the outer ring during rotation was detected by a speed sensor, and the Anderon value was measured. The number of peak occurrences originating from coarse particles of the thickener during the measurement time was counted. A lower count indicates a grease composition with improved acoustic characteristics. Five measurements were performed, and the average values ​​are shown in Table 1. 【0062】 【0063】As shown in Table 1, the grease composition produced by the manufacturing method of the example had better acoustic properties than the grease composition produced by the manufacturing method of the comparative example. 【0064】 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. 【0065】 1, 2: Vibrating agitator 3, 23: Inlet A 5: Inlet B 6, 26: Flow path 7, 27: Outlet 8, 28: Partition 9, 29: Container 11, 22: Helical stirring blade 13: Tank 15, 25: Tank 17, 19, 21: Pump

Claims

1. A method for producing a grease composition, comprising a reaction mixing step of reacting and simultaneously mixing and dispersing a mixed solution A containing a thickening agent raw material A and a solvent A, and a mixed solution B containing a thickening agent raw material B and a solvent B, using a vibrating stirrer, wherein the reaction mixing step involves continuously supplying the mixed solution A and the mixed solution B to the vibrating stirrer, and causing the mixed solution A and the mixed solution B to react and mix by reciprocating a spiral stirring blade provided in the container of the vibrating stirrer in a direction along the axis of the stirring blade.

2. A method for producing a grease composition, comprising a mixing step of mixing a mixed solution containing a thickener and a solvent with a vibrating stirrer, wherein the mixing step is performed by continuously supplying the mixed solution to the vibrating stirrer, and causing a spiral stirring blade provided in the container of the vibrating stirrer to reciprocate in a direction along the axis of the stirring blade to mix the mixed solution.

3. A method for producing a grease composition, comprising: mixing step A to produce alkali metal soap solution A or alkaline earth metal soap solution A by mixing a mixed solution A1 containing solvent A1 and fatty acid A1 with a mixed solution A2 containing solvent A2 and alkali metal hydroxide or alkaline earth metal hydroxide; mixing step B to produce alkali metal soap solution B or alkaline earth metal soap solution B by mixing a mixed solution B1 containing solvent B1 and fatty acid B1 with a mixed solution B2 containing solvent B2 and the alkali metal hydroxide or alkaline earth metal hydroxide; and mixing step C to produce alkali metal complex soap or alkaline earth metal complex soap by mixing alkali metal soap solution A or alkaline earth metal soap solution A with alkali metal soap solution B or alkaline earth metal soap solution B. Mixing step A involves continuously supplying the mixed solution A1 and the mixed solution A2 to a vibrating agitator, and mixing the mixed solution A1 and the mixed solution A2 by causing a spiral stirring blade provided in the container of the vibrating agitator to reciprocate in a direction along the axis of the stirring blade. Mixing step B involves continuously supplying the mixed solution B1 and the mixed solution B2 to a vibrating agitator, and mixing the mixed solution B1 and the mixed solution B2 by causing a spiral stirring blade provided in the container of the vibrating agitator to reciprocate in a direction along the axis of the stirring blade. The mixing step C is a method for producing a grease composition, wherein the alkali metal soap solution A or the alkaline earth metal soap solution A and the alkali metal soap solution B or the alkaline earth metal soap solution B are continuously supplied to a vibrating agitator, and a spiral stirring blade provided in the container of the vibrating agitator moves back and forth in a direction along the axis of the stirring blade, thereby mixing the alkali metal soap solution A or the alkaline earth metal soap solution A and the alkali metal soap solution B or the alkaline earth metal soap solution B.

4. A method for producing a grease composition, comprising a mixing step of mixing a mixed solution A containing solvent A, fatty acid A, and fatty acid B, and a mixed solution B containing solvent B and alkali metal hydroxide or alkaline earth metal hydroxide to produce alkali metal complex soap or alkaline earth metal complex soap, wherein the mixing step involves continuously supplying the mixed solution A and the mixed solution B to a vibrating agitator, and causing a spiral stirring blade provided in the container of the vibrating agitator to reciprocate in a direction along the axis of the stirring blade to react and mix the mixed solution A and the mixed solution B.

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