Manufacturing method of urea grease

Abstract

To provide a production method of urea grease excellent in acoustic characteristics and fretting resistance.SOLUTION: A production method of urea grease comprises a step of mixing a fluid containing at least one monoamine compound selected from chain aliphatic monoamines, alicyclic monoamines, and aromatic monoamines, and a diisocyanate compound, using a mixer equipped with flow paths that can merge and mix fluids, and guide vanes.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for producing a urea grease. [Background technology]

[0002] It is known that grease, especially urea grease, contains non-uniform particles generally called lumps, including those thought to be derived from the reaction product of isocyanate and amine. Since lumps deteriorate the acoustic properties of the grease, various methods for producing urea grease to suppress the generation of lumps have been investigated.

[0003] In Patent Document 1, a mixture of a monoamine compound and a diisocyanate compound is added to a 10 2 s -1 It is described that by applying shear at the minimum shear rate above, a urea grease with few lumps and excellent acoustic properties can be produced. However, this method has problems such as a slow processing speed, and is not necessarily a satisfactory method for commercial production.

[0004] Furthermore, rolling bearings and the like are required to have excellent fretting resistance, high-temperature and high-speed durability, reduced rotational torque, and the like, depending on their applications. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6609243 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention aims to provide a method for producing a novel urea grease which has improved acoustic properties and fretting resistance when compared with greases having the same types and amounts of base oil and diurea compound. [Means for solving the problem]

[0007] The present inventors have found that the above-mentioned problem can be solved by mixing fluids containing a predetermined monoamine compound and a diisocyanate compound using a mixer equipped with a flow path and guide vanes capable of mixing fluids, and have completed the present invention.

[0008] That is, the present invention provides [1] A method for producing a urea grease, comprising a step of mixing a fluid containing at least one monoamine compound selected from a chain aliphatic monoamine, an alicyclic monoamine, and an aromatic monoamine, and a diisocyanate compound, using a mixer equipped with a flow path and guide vanes capable of merging and mixing fluids; [2] A method for producing the urea grease described in [1] above, comprising a step of passing at least one of a base oil 1 containing at least one monoamine compound selected from the group consisting of a chain aliphatic monoamine, an alicyclic monoamine, and an aromatic monoamine, and a base oil 2 containing a diisocyanate compound through the guide vane, and a step of joining the base oil 1 and the base oil 2; [3] A method for producing a urea grease according to the above [1] or [2], wherein the mixer has at least two of the flow paths that join upstream of the guide vane, and the step of mixing the fluids includes a step of joining a base oil 1 containing at least one of the monoamine compounds selected from a chain aliphatic monoamine, an alicyclic monoamine, and an aromatic monoamine, and a base oil 2 containing a diisocyanate compound, upstream of the guide vane, and a step of passing the fluid obtained by joining the base oil 1 and the base oil 2 through the guide vane. [4] A method for producing a urea grease according to any one of the above [1] to [3], wherein, when a distance from a confluence of two flow paths where the base oil 1 and the base oil 2 are joined to a downstream end of the guide vane is X (mm), and an average flow velocity of the fluid from the confluence of the flow paths to the downstream end of the guide vane is Vx (mm / s), X / Vx is 1.0 or less. [5] The method for producing a urea grease according to [4] above, wherein the Vx is 100 mm / s or more. [6] A method for producing a urea grease according to the above [1] or [2], comprising a step of: the guide vane has a plurality of independent inlets for introducing fluids; and the base oil 1 containing at least one monoamine compound selected from the group consisting of a chain aliphatic monoamine, an alicyclic monoamine, and an aromatic monoamine, and the base oil 2 containing a diisocyanate compound are passed through the guide vane via the respective independent inlets, and merged downstream of the guide vane; [7] The method for producing a urea grease according to any one of the above [1] to [6], wherein, when a distance from a downstream end of the guide vane to a discharge port of the mixer is Y (mm) and an average flow velocity of the fluid from the downstream end of the guide vane to the discharge port of the mixer is Vy (mm / s), Y / Vy is 0.0005 or more. [8] The method for producing a urea grease according to any one of the above [1] to [7], wherein the mixer further has a protruding impact body on the inner wall of the flow passage downstream of the guide vane. [9] The method for producing a urea grease according to any one of [1] to [8] above, wherein the urea grease further contains a detergent dispersant.

[10] A method for producing a urea grease according to any one of [1] to [9] above, wherein the content of the base oil in the urea grease is 50 to 95 mass%.

[11] The present invention relates to a method for producing a bearing, a gear, or a spindle, the method including a step of applying a urea grease produced by the production method according to any one of the above [1] to

[10] . Effect of the Invention

[0009] According to the present invention, it is possible to produce a urea grease that has improved acoustic properties and fretting resistance when compared with greases containing the same types and amounts of base oil and diurea compound. [Brief description of the drawings]

[0010] [Figure 1] 1 is a partial cross-sectional view of a pipe of a mixer according to an embodiment of the present invention, taken along the longitudinal direction of the pipe. [Diagram 2] FIG. 4 is a partial cross-sectional view showing another embodiment of the mixer. [Diagram 3] FIG. 4 is a partial cross-sectional view showing another embodiment of the mixer. [Figure 4] FIG. 4 is a partial cross-sectional view showing another embodiment of the mixer. [Diagram 5] FIG. 4 is a partial cross-sectional view showing another embodiment of the mixer. [Figure 6] 6 is a cross-sectional view taken along line AA in FIG. 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The method for producing the urea grease according to this embodiment is characterized by including a step of mixing a fluid containing at least one monoamine compound selected from a chain aliphatic monoamine, an alicyclic monoamine, and an aromatic monoamine, and a diisocyanate compound, using a mixer equipped with a flow path and guide vanes capable of joining and mixing fluids.

[0012] The method for producing the urea grease according to this embodiment preferably includes a step of passing at least one of a base oil 1 containing at least one monoamine compound selected from among a chain aliphatic monoamine, an alicyclic monoamine, and an aromatic monoamine, and a base oil 2 containing a diisocyanate compound through the guide vane, and a step of merging the base oil 1 and the base oil 2.

[0013] It is more preferable that the method for producing the urea grease according to this embodiment includes a step in which the mixer has at least two flow paths that join upstream of the guide vane, and includes a step of joining a base oil 1 containing at least one monoamine compound selected from among a chain aliphatic monoamine, an alicyclic monoamine, and an aromatic monoamine, and a base oil 2 containing a diisocyanate compound, upstream of the guide vane, and a step of passing the joined fluid of the base oil 1 and the base oil 2 through the guide vane.

[0014] A method for producing a urea grease according to one embodiment of the present invention will be described in detail below. However, the following description is an example for explaining the present invention, and is not intended to limit the technical scope of the present invention to only this described range. In this specification, when a numerical range is indicated using "~", the numerical values ​​at both ends are included.

[0015] <Urea grease and its manufacturing method> The urea grease according to the present embodiment contains a diurea compound obtained by reacting at least one monoamine compound selected from a chain aliphatic monoamine, an alicyclic monoamine, and an aromatic monoamine with a diisocyanate compound, and a base oil. In addition, the urea grease may contain components other than the above components (other components) within a range that does not impair the effects of the present invention.

[0016] (Diurea compounds) The diurea compound according to the present embodiment can be obtained by reacting at least one monoamine compound selected from the group consisting of chain aliphatic monoamines, alicyclic monoamines, and aromatic monoamines with a diisocyanate compound.

[0017] From the viewpoints of boiling point and solubility, the number of carbon atoms in the chain aliphatic monoamine is preferably 6 to 24, more preferably 6 to 20, and further preferably 8 to 18. Specific examples of the chain aliphatic monoamine include hexylamine, octylamine, dodecylamine, hexadecylamine, stearylamine, and eicosylamine. These chain aliphatic monoamines may be used alone or in combination of two or more.

[0018] Specific examples of alicyclic monoamines include cycloalkylamines or substituted alkylcycloalkylamines having 4 to 12 carbon atoms, specifically cyclohexylamine, 4-alkyl-substituted cyclohexylamine, cyclobutylamine, cyclopentylamine, cycloheptylamine, etc. These alicyclic monoamines may be used alone or in combination of two or more.

[0019] Specific examples of aromatic monoamines include tolylamine, aniline, trimethylaniline, etc. These aromatic monoamines may be used alone or in combination of two or more.

[0020] As the diisocyanate compound, aromatic diisocyanates are preferably used because the heat resistance of the grease is good, and examples thereof include diphenylmethane-4,4'-diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, a mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, 3,3'-dimethyldiphenyl-4,4'-diisocyanate, etc. In particular, diphenylmethane-4,4'-diisocyanate and 2,6-tolylene diisocyanate are preferred because of their good availability, and diphenylmethane-4,4'-diisocyanate is more preferred because of its good heat resistance.

[0021] The diurea compound, which is the reaction product obtained by the above reaction, is represented by the following general formula (I): 2 is a hydrocarbon group derived from the diisocyanate compound. 1 and R 3 are each independently a hydrocarbon group derived from the chain aliphatic amine, the alicyclic amine, or the aromatic amine. [ka]

[0022] The content of the diurea compound can be appropriately adjusted so that the urea grease has the desired worked penetration, and can be, for example, in the range of 1 to 40 mass%, 2 to 30 mass%, 3 to 25 mass%, or 4 to 20 mass% in the urea grease.

[0023] (Base oil) The base oil is not particularly limited, and examples thereof include mineral oil-based base oils and synthetic base oils used in normal grease manufacturing. Mineral oil-based base oils can be those refined by an appropriate combination of vacuum distillation, solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, sulfuric acid washing, clay refining, and hydrorefining. Synthetic base oils can include polyalphaolefin (PAO)-based base oils, other hydrocarbon-based base oils, ester-based base oils, alkyl diphenyl ether-based base oils, polyalkylene glycol-based base oils (PAG), and alkyl benzene-based base oils.

[0024] The kinematic viscosity of the base oil at 40°C is not particularly limited as long as it is within the range of viscosity usually used for grease, but is preferably 5 to 3300 mm 2 / s is preferable, and 10 to 2000 mm 2 / s is more preferable, and 15 to 1000 mm 2 / s is more preferable, and 20 to 500 mm 2 / s is particularly preferred.

[0025] The content of the base oil in the urea grease is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and particularly preferably 75% by mass or more. If the content of the base oil is less than 50% by mass, the mixed consistency of the grease composition tends to decrease, and the torque tends to increase. In addition, the content of the base oil is preferably 95% by mass or less, more preferably 94% by mass or less, and even more preferably 93% by mass or less. If the content of the base oil exceeds 95% by mass, excessive oil separation tends to occur, and leakage, scattering, etc. from the place of use tend to occur.

[0026] The urea grease according to this embodiment may contain various additives such as detergent dispersants, antiwear agents, antioxidants, extreme pressure additives, dyes, color stabilizers, thickeners, structure stabilizers, metal deactivators, viscosity index improvers, and rust inhibitors in appropriate amounts, provided that the effects of the present invention are not impaired. When these various additives are contained, the total content of the additives in the urea grease is preferably 10% by mass or less, more preferably 8.0% by mass or less, even more preferably 6.0% by mass or less, and particularly preferably 4.0% by mass or less.

[0027] Examples of detergent dispersants include overbased metal sulfonates, metal sulfonates, metal phenates, metal salicylates, metal phosphanates, and succinimides, and metal sulfonates and succinimides are preferred.Examples of overbased metal sulfonates, metal sulfonates, metal phenates, metal salicylates, and metal phosphanates include calcium and magnesium, and calcium is preferred.By using the detergent dispersant, the generation of clumps can be more effectively suppressed.

[0028] The content of the detergent dispersant can be appropriately adjusted so as to suppress the generation of lumps, and can be, for example, in the range of 0.1 to 5.0 mass %, 0.2 to 3.0 mass %, or 0.3 to 1.5 mass % in the urea grease.

[0029] Examples of the anti-wear agent include methylenebisdithiocarbamate, polycarboxylate, zinc-based anti-wear agents, sulfur-based anti-wear agents, and phosphorus-based anti-wear agents.

[0030] The antioxidant is not particularly limited as long as it is one that is generally added to grease compositions, but aromatic amine-based antioxidants are preferred, such as diphenylamine, alkylated diphenylamine, phenothiazine, N-phenyl-α-naphthylamine, p,p'-diaminodiphenylmethane, aldol-α-naphthylamine, and p-dodecylphenyl-1-naphthylamine.

[0031] Examples of the extreme pressure additives include ashless extreme pressure additives such as ashless dithiocarbamate (ashless DTC), sulfurized oils and fats, phosphates, ashless dithiophosphates (ashless DTP), and SP-based extreme pressure additives; and extreme pressure additives other than ashless extreme pressure additives such as antimony dithiocarbamate (SbDTC), bismuth dibutyldithiocarbamate (BiDTC), and zinc dithiocarbamate (ZnDTC).

[0032] The worked penetration of the urea grease according to this embodiment is not particularly limited and can be adjusted according to the application, and is preferably adjusted to, for example, 220 to 385. Note that the worked penetration in this specification is determined in accordance with JIS K 2220 7 and refers to a value calculated by multiplying the depth (mm) of penetration over 5 seconds by 10 when a cone attached to a penetration meter is dropped into the grease composition in an environment of 25°C.

[0033] The urea grease according to the present embodiment can be applied to various parts and mechanical parts that move relative to each other in the following: power transmission devices such as reducers, speed increasers, gears, chains, and motors; driving system parts; control system parts such as ABS; steering system parts; drive system parts such as transmissions, automotive reinforcement parts such as power window motors, power seat motors, and sunroof motors; hinge parts for electronic information devices and mobile phones; food industry, pharmaceutical industry, steel industry, construction industry, glass industry, cement industry, chemical, rubber, and resin industries such as film tenters, environmental and power equipment, paper and printing industries, wood industry, and textile and apparel industries. It can also be applied to bearings such as rolling bearings, thrust bearings, dynamic pressure bearings, resin bearings, and linear motion devices. The urea grease according to the present embodiment is preferably applied to bearings, gears, spindles, and the like, because it has excellent acoustic properties and fretting resistance.

[0034] [Method of producing urea grease] The method for producing the urea grease according to this embodiment is characterized by including a step of mixing a fluid containing at least one monoamine compound selected from aliphatic monoamines, alicyclic monoamines, and aromatic monoamines, and a diisocyanate compound, using a mixer equipped with a flow path and guide vanes capable of joining and mixing fluids.

[0035] The mixer used for producing the urea grease according to this embodiment is not particularly limited as long as it is a mixer equipped with a flow path and guide vanes that can join and mix the fluids. The mixing of the fluids is performed by a step of joining the fluids, a step of stirring the fluids by a spiral flow after passing through the guide vane 12, and a step of finely atomizing the fluid by colliding it with the collision body 16, if necessary.

[0036] In this specification, the term "guide vane" refers to a mechanism that has an inlet for introducing a fluid and generates a spiral flow by changing the angle from the inlet.

[0037] FIG. 1 is a cross-sectional view showing the configuration of a mixer according to an embodiment of the present invention, but the present invention is not limited to such an embodiment. The mixer 1 includes a guide vane 12 provided in a pipe, and flow paths 2a and 2b that join upstream of the guide vane 12. The flow paths 2a and 2b may be formed by two different pipes that join each other (see FIGS. 1 to 4), or may be formed by separating one pipe by a partition or the like. The mixer 1 merges the base oil 1 containing the predetermined monoamine compound that has passed through one of the flow paths 2a and 2b and the base oil 2 containing the diisocyanate compound that has passed through the other of the flow paths 2a and 2b at a joining point in the flow paths (for example, a point where the axes of the flow paths 2a and 2b intersect), and passes the guide vane 12 provided in the flow paths. When the joined fluid passes through the guide vane 12, the fluid is converted into a spiral flow, and a strong centrifugal force is generated. At this time, due to the difference in specific gravity between the fluids, the heavy fluid is distributed to the radially outer side of the flow path, and the light fluid is distributed to the radially inner side of the flow path, and the boundary layer separation generates intense turbulence, stirring the fluids. Then, the microparticles of the heavy fluid and the microparticles of the light fluid continuously collide and react with each other violently due to centrifugal force and centripetal force, and the generated urea grease is thought to be further broken down into fine particles.

[0038] In order to further promote the fine particle formation of the urea grease, the mixer 1 may further provide a protruding collision body 16 on the inner wall of the flow passage downstream of the guide vane 12. The collision body 16 protrudes radially inward from the inner wall of the flow passage (the inner surface of the pipe). In this embodiment, a plurality of collision bodies 16 are provided in the axial direction of the pipe. The number, shape, and height of the collision bodies 16 are not particularly limited and can be changed arbitrarily. The height of the collision bodies 16 may be set so that there is a gap between the tips of the collision bodies 16 when viewed in the axial direction of the pipe body of the mixer 1 as shown in FIG. 1, or may be set so that the collision bodies 16 overlap or intersect (i.e., the length of the collision body 16 is longer than the radius of the inner surface of the pipe) when viewed in the axial direction of the pipe of the mixer 1 as shown in FIG. 3.

[0039] The piping of the flow passages 2a and 2b located upstream of the guide vane 12 is not particularly limited, but may be, for example, as shown in Fig. 1, a first pipe having a flow passage 2a extending coaxially with the flow passage downstream of the guide vane, and a second pipe having a flow passage 2b extending at an angle to the flow passage 2a and joining the flow passage 2a, or as shown in Fig. 2, a Y-shaped pipe having a first pipe having a flow passage 2a inclined with respect to the flow passage downstream of the guide vane 12, and a second pipe having a flow passage 2b inclined on the opposite side to the first flow passage with respect to the flow passage downstream of the guide vane 12. In this way, when the flow passages 2a and 2b are joined upstream of the guide vane 12, there is an advantage that (1) in addition to the shearing action caused by the guide vane converting the laminar flow to a spiral flow, (2) the dispersion of the urea grease is promoted by the boundary layer separation caused by the impact body.

[0040] 4, the flow path 2b led from the upstream side of the mixer 1 may be made to penetrate the central axis of the guide vane 12. In this way, when the flow paths 2a and 2b are joined downstream of the guide vane 12, the fluid passing through the flow path 2b is not subjected to the shearing action of the guide vane, and therefore the micronization effect is inferior. However, since the reaction starts under the intense turbulence generated by the impactor 16, there is an advantage that the aggregation of the generated urea grease is suppressed.

[0041] Also, each of the flow paths 2a and 2b may be independently connected to a plurality of inlets of the guide vane 12, and the base oil 1 containing the predetermined monoamine compound and the base oil 2 containing the diisocyanate compound may be passed through the guide vane 12 via independent flow paths and inlets, and may be joined downstream of the guide vane 12 to start the reaction (see FIG. 5). In this case, the base oil 1 and the base oil 2 are each subjected to a shearing action by the guide vane, so there is no reduction in the micronization effect, and the reaction is started under the intense turbulence generated by the impact body 16, so there is an advantage that the aggregation of the generated urea grease is suppressed. In addition, in FIG. 5 and FIG. 6, the pipe is radially divided into two by the partition plate 15 on the upstream side of the guide vane 12, thereby forming the flow paths 2a and 2b. The base oil 1 flowing through the flow path 2a flows along the surface of the elliptical disk 13 of the guide vane 12 to the downstream side of the guide vane 12, and the base oil 2 flowing through the flow path 2b flows along the surface of the elliptical disk 13 of the guide vane 12 to the downstream side of the guide vane 12. 2 is , and flows along the surface of the elliptical disk 14 of the guide vane 12 to the downstream side of the guide vane 12 .

[0042] The guide vane 12 shown in Fig. 1 has a structure in which the chord side edges 13a, 14a of a pair of split elliptical disks 13, 14 cross in an X-shape. The guide vane 12 also has a structure in which the chord side edges 13a, 14a upstream of the crossing are closed by a partition plate 15 that divides the inside of the mixer 1 in the axial direction. The shape of the partition plate 15 is not particularly limited, but a triangle is preferable. The arc side edges 13b, 14b of the pair of split elliptical disks 13, 14 are disposed in the mixer 1 so as to be joined to the inner wall of the flow path.

[0043] The base oils constituting base oil 1 and base oil 2 are not particularly limited and the above-mentioned base oils can be used, but in consideration of the compatibility between base oil 1 and base oil 2, it is preferable that base oil 1 and base oil 2 have similar polarity or viscosity characteristics. For this reason, it is more preferable to use the same base oil for base oil 1 and base oil 2.

[0044] From the viewpoint of the solubility of the monoamine compound, the temperature of the base oil 1 containing the predetermined monoamine compound is preferably from room temperature to 120° C. In addition, the mass ratio of the monoamine compound to the base oil in the base oil 1 is preferably 2 kg or less of the monoamine compound per 1 kg of the base oil.

[0045] From the viewpoint of the solubility of the diisocyanate compound, the temperature of the base oil 2 containing the diisocyanate compound is preferably 50 to 100° C. In addition, the mass ratio of the diisocyanate compound to the base oil in the base oil 2 is preferably 2 kg or less of the diisocyanate compound per 1 kg of the base oil.

[0046] The reaction temperature between the monoamine compound and the diisocyanate compound is not particularly limited and may be the same as that of a typical reaction of this type. From the viewpoint of the solubility and volatility of the monoamine compound and the diisocyanate compound, the reaction temperature is preferably 50 to 170°C, more preferably 60 to 150°C.

[0047] The reaction between the amino group of the monoamine compound and the isocyanate group of the diisocyanate compound is considered to proceed quantitatively. The molar ratio of the monoamine compound to the diisocyanate compound is preferably 1.0 to 1.1 moles of the diisocyanate compound per 2 moles of the total amount of the monoamine compound.

[0048] When the distance from the junction of the two flow paths where the base oil 1 and the base oil 2 join to the downstream end of the guide vane 12 is X (mm), and the average flow velocity of the fluid from the junction of the flow paths to the downstream end of the guide vane 12 is Vx (mm / s), X / Vx (s) is preferably 1.0 or less, more preferably 0.75 or less, and even more preferably 0.50 or less. Since the reaction between the monoamine compound and the diisocyanate compound is very fast, if the arrival time from the junction of the base oil 1 and the base oil 2 to the guide vane 12 becomes long, the reaction between the monoamine compound and the diisocyanate compound progresses, and the urea grease aggregates and tends to generate lumps. By setting X / Vx in the above range and passing the fluid through the guide vane 12 before the reaction between the monoamine compound and the diisocyanate compound is completed, the shearing of the urea grease is promoted, and the urea grease can be effectively finely divided. The lower limit of X / Vx is not particularly limited.

[0049] In this specification, the "junction of two flow paths where base oil 1 and base oil 2 join" refers to the intersection of the cross-sectional center lines (axial centers) of flow paths 2a and 2b. The average flow velocity Vx (mm / s) is calculated based on the volume of the fluid discharged from outlet 17 per unit time and the cross-sectional area of ​​the pipe in the length X region (i.e., the region from the junction of the flow paths to the downstream end of guide vane 12).

[0050] From the viewpoint of suppressing the generation of lumps due to aggregation of the urea grease and from the viewpoint of enhancing the mixability of the fluid by the turbulent flow effect, it is preferable to increase the average flow velocity Vx, which can be, for example, 100 mm / s or more, 300 mm / s or more, 500 mm / s or more, 700 mm / s or more, 900 mm / s or more, or 1100 mm / s or more. The upper limit of the average flow velocity Vx is not particularly limited as long as the pump capacity and the durability of the flow path allow, but can be, for example, 3000 mm / s or less, 2500 mm / s or less, or 2000 mm / s or less.

[0051] When the distance from the downstream end of the guide vane to the outlet 17 of the mixer is Y (mm) and the average flow velocity of the fluid from the downstream end of the guide vane to the outlet 17 of the mixer is Vy (mm / s), Y / Vy(s) is preferably 0.0005 or more, more preferably 0.001 or more, and even more preferably 0.002 or more. By setting Y / Vy in the above range and ensuring the arrival time from the downstream end of the guide vane to the outlet 17 of the mixer, the reaction between the monoamine compound and the diisocyanate compound can be completed and the urea grease can be effectively made into fine particles. In addition, Y / Vy(s) is preferably 0.10 or less, more preferably 0.050 or less, and even more preferably 0.030 or less. If Y / Vy(s) exceeds 0.10, the fine particle formation is insufficient and coarse particles are easily generated.

[0052] The reaction rate with the diisocyanate compound varies depending on the type of monoamine compound. Therefore, it is preferable to increase Y / Vy within an appropriate range for monoamine compounds with a slow reaction rate, and it is preferable to decrease Y / Vy within an appropriate range for monoamine compounds with a fast reaction rate. Examples of monoamine compounds with a slow reaction rate include behenylamine, paradodecylamine, and toluidine. On the other hand, examples of monoamine compounds with a fast reaction rate include octylamine and cyclohexylamine.

[0053] The average flow velocity Vy may be, for example, 1000 mm / s or more, 3000 mm / s or more, 5000 mm / s or more, 7000 mm / s or more, 9000 mm / s or more, or 11000 mm / s or more. The upper limit of Vy is not particularly limited as long as the pump capacity and the durability of the flow path allow, but may be, for example, 30000 mm / s or less, 25000 mm / s or less, or 20000 mm / s or less.

[0054] The average flow velocity Vy (mm / s) is calculated based on the volume of the fluid discharged from the discharge port 17 per unit time and the cross-sectional area of ​​the discharge port 17.

[0055] The urea grease according to the present embodiment can be obtained by holding the urea grease discharged from the mixer 1 at, for example, 120 to 250°C for 10 to 60 minutes, then cooling it to about 100°C and homogenizing it using a homogenizer. The obtained grease may be further homogenized using a roll mill that is commonly used in grease production. EXAMPLES

[0056] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these.

[0057] In this example, the following raw materials were used: MDI: Diphenylmethane-4,4'-diisocyanate Mineral oil: 500N mineral oil (40℃ kinematic viscosity: 97.5mm 2 / s)

[0058] Urea grease was produced using the mixer shown in Figure 1. The distance X from the junction of two flow paths where the below-mentioned base oil 1 and the below-mentioned base oil 2 join to the downstream end of the guide vane is 140 (mm), and the distance Y from the downstream end of the guide vane to the discharge port of the mixer is 45 (mm). The specific production method is as follows.

[0059] (Examples 1 to 3) Base oil 1 (500N mineral oil containing the amine mixture described in Examples 1 to 3 heated to 60 ° C., the mass ratio of the amine mixture to the 500N mineral oil is 1:11) and base oil 2 (500N mineral oil containing MDI heated to 60 ° C., the mass ratio of MDI to the 500N mineral oil is 1:11) were joined upstream of the guide vane and passed through the guide vane continuously at the flow rate shown in Table 1. The urea grease discharged from the mixer was held at 160 ° C. for 30 minutes, cooled to about 100 ° C., and homogenized using a homogenizer. The properties of the obtained urea grease were evaluated by the method described below, and the results are shown in Table 1. The molar ratio of MDI indicates the molar ratio of MDI to the total amount of 2 moles of monoamine compounds.

[0060] Example 4 Base oil 1 (500N mineral oil containing the amine mixture described in Example 4 heated to 60 ° C, the mass ratio of the amine mixture to the 500N mineral oil is 1:5) and base oil 2 (500N mineral oil containing MDI heated to 60 ° C, the mass ratio of MDI to the 500N mineral oil is 1:5) were joined upstream of the guide vane and passed through the guide vane continuously at the flow rate shown in Table 1. The urea grease discharged from the mixer was held at 160 ° C for 30 minutes, cooled to about 100 ° C, and homogenized using a homogenizer. The properties of the obtained urea grease were evaluated by the method described below, and the results are shown in Table 1. The molar ratio of MDI indicates the molar ratio of MDI to the total amount of 2 moles of monoamine compounds.

[0061] (Comparative Examples 1 and 2) A urea grease was produced by a normal method. Specifically, according to the recipe in Table 1, the mixture of amine compounds was mixed with the same mass part of base oil, and dissolved by heating to 60 ° C. to prepare solution A. Separately, according to Table 1, the same mass part of MDI was mixed with base oil, calcium sulfonate was added, and solution B was prepared by heating to 60 ° C. to prepare solution B. Next, the remaining base oil was heated to 60 ° C., mixed with the above solution A, and solution B was gradually added while stirring the mixture. After holding at 160 ° C. for 30 minutes, it was cooled to about 100 ° C. and homogenized using a homogenizer. The properties of the obtained urea grease were evaluated by the method described below, and the results are shown in Table 1. The molar ratio of MDI indicates the molar ratio of MDI to the total amount of 2 moles of monoamine compounds.

[0062] <Measurement of worked penetration> In accordance with JIS K 2220 7, a cone attached to a penetration meter was dropped into the grease at 25°C, and the depth (mm) of penetration was measured over 5 seconds. The measured value was multiplied by 10 to obtain the worked penetration.

[0063] <Amount of wear on the fastener> A fretting resistance test was conducted in accordance with ASTM D4170, and the amount of fretting wear (mg) was measured from the difference in mass before and after the test. The smaller the amount of fretting wear, the better the fretting resistance. The performance target value is 10mg or less.

[0064] <Acoustic Test> Acoustic testing was conducted in accordance with the More Quiet method (MQ method) of ISO 21250-3:2020. Ungreased bearings designed for acoustic measurement were placed in an SKF grease-specific acoustic measurement device (Grease Test Rig Be Quiet+), and acoustic data was obtained from 32 to 64 seconds after the start of rotation while rotating at a specified speed. Next, a specified amount of sample (grease) was injected into these bearings, and acoustic data was obtained from 32 to 64 seconds after the start of rotation while rotating at a specified speed. These operations were performed five times, and the grease noise class was determined by analyzing the data using a program built into the acoustic measurement device.

[0065] [Table 1]

[0066] The results in Table 1 show that the urea grease of the present invention, obtained by mixing a fluid containing a specified monoamine compound and a diisocyanate compound using a mixer equipped with a flow path and guide vanes capable of mixing fluids, has improved acoustic properties and fretting resistance when compared with greases containing the same types and amounts of base oil and diurea compound. [Explanation of symbols]

[0067] 1. Mixer 2a, 2b, 2c... Flow path 12 Guide vane 13, 14: Two-piece elliptical disk 13a, 14a... Chord side edge 13b, 14b... Arc side edge 15... Partition plate 16···Conflict Body 17···Spit out

Claims

1. A method for producing urea grease using a mixer, comprising the steps of: The mixer includes a flow passage for passing a fluid, a guide vane, and a protruding impact body on an inner wall of the flow passage downstream of the guide vane, The fluid includes a base oil, at least one monoamine compound selected from a chain aliphatic monoamine, an alicyclic monoamine, and an aromatic monoamine, and a diisocyanate compound; The method includes a step of mixing the monoamine compound and the diisocyanate compound in the fluid.

2. a step of passing one of a base oil 1 containing at least one monoamine compound selected from the group consisting of a chain aliphatic monoamine, an alicyclic monoamine, and an aromatic monoamine, and a base oil 2 containing a diisocyanate compound through the guide vane; and 2. The method for producing a urea grease according to claim 1, further comprising a step of passing the other of the base oil 1 and the base oil 2 through a flow passage penetrating the central axis of the guide vane, and merging the base oil 1 and the base oil 2 downstream of the guide vane and upstream of the collision body.

3. the mixer having at least two of the flow paths joining together upstream of the guide vanes; A step of joining a base oil 1 containing at least one monoamine compound selected from the group consisting of a chain aliphatic monoamine, an alicyclic monoamine, and an aromatic monoamine, and a base oil 2 containing a diisocyanate compound upstream of the guide vane; and The method for producing a urea grease according to claim 1 , further comprising a step of passing a fluid obtained by joining the first base oil and the second base oil through the guide vane.

4. 4. The method for producing a urea grease according to claim 3, wherein, when a distance from a confluence of two flow paths where the base oil 1 and the base oil 2 are confluent to a downstream end of the guide vane is X (mm), and an average flow velocity of the fluid from the confluence of the flow paths to the downstream end of the guide vane is Vx (mm / s), X / Vx is 1.0 or less.

5. The method for producing a urea grease according to claim 4, wherein the Vx is 100 mm / s or more.

6. Each of the plurality of flow paths is independently connected to a plurality of inlets of the guide vane, 2. A method for producing a urea grease according to claim 1, comprising a step of passing a base oil 1 containing at least one monoamine compound selected from the group consisting of a chain aliphatic monoamine, an alicyclic monoamine, and an aromatic monoamine, and a base oil 2 containing a diisocyanate compound through the guide vane via the flow paths and the inlets, each of which is independent of the other, and allowing the two oils to join downstream of the guide vane.

7. The method for producing a urea grease according to any one of claims 1 to 6, wherein Y / Vy is 0.0005 or more, where Y is a distance (mm) from the downstream end of the guide vane to the discharge port of the mixer, and Vy is an average flow velocity of the fluid from the downstream end of the guide vane to the discharge port of the mixer.

8. The method for producing a urea grease according to any one of claims 1 to 7, wherein the urea grease further contains a detergent dispersant.

9. The method for producing a urea grease according to any one of claims 1 to 8, wherein the content of the base oil in the urea grease is 50 to 95 mass%.

10. A method for manufacturing a bearing, a gear, or a spindle, comprising a step of applying a urea grease manufactured by the manufacturing method according to any one of claims 1 to 9.

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