JP6505451B2 - Urea grease - Google Patents

Description

  The present invention relates to urea grease.

It is known that grease, in particular diurea-based grease, is mixed with non-uniform particles generally called lumps. These include those that are believed to be derived from the reaction of isocyanate and amine, and contaminants that are introduced during the manufacturing process, storage process, etc., which degrade the acoustic properties of the grease.
In a usual method for producing urea grease, while heating and stirring a solution of base oil and thickener precursor 1 to about 60 ° C., a solution of base oil and thickener precursor 2 is added, and the temperature is raised to 160 ° C. Allow to cool to room temperature. However, this method requires several hours to manufacture and tends to form a nonuniform structure such as damas. Such dams are considered to reduce the acoustic characteristics.
Then, suppressing generation | occurrence | production of a dama, reducing dams, and improving acoustic characteristics is examined, and the manufacturing method of various urea grease is proposed (patent documents 1-6).

Unexamined-Japanese-Patent No. 2000-248290 Unexamined-Japanese-Patent No. 03-190996 JP 02-004895 A JP 2014-208851 A JP, 2013-535545, A JP, 2013-535546, A

However, in the method for producing urea grease described in Patent Document 1, the amine solution is formed into droplets of 300 μm or less by the spray nozzle and charged into the diphenylmethane-4,4'-diisocyanate (hereinafter referred to as MDI) solution. There are concerns about environmental pollution and drug damage caused by the scattering of amines and MDI. Moreover, in this method, there is a possibility that a non-uniform structure of 300 μm or less in droplet diameter is formed, and a lump of about several tens of μm in size is formed.
The method for producing urea grease described in Patent Document 2 is a method in which an amine solution and an isocyanate solution are pressurized to a predetermined pressure using a pressure device, and both solutions are collided and reacted to react. There is concern that environmental pollution and drug damage may be caused by the Moreover, in this method, a nonuniform structure equal to or less than the droplet diameter is formed, and there is a possibility that a lump of about several tens of μm in size may be formed.
The method of producing urea grease described in Patent Document 3 is a method of dispersing lumps by mechanical means such as a roll mill after or during formation of a thickener, but it takes time and effort. Since the reaction product-derived dams are hard and difficult to be dispersed, the method is not a sufficient method in terms of refining the dams.
In the method for producing urea greases described in Patent Documents 4 to 6, although the grease is produced by high-pressure jet mixing, it is costly in equipment and it is not a sufficient method in terms of refining of lumps. .

As described above, the methods for producing the urea greases described in Patent Documents 1 to 4 are all inadequate methods in terms of refining of the dams, and have not been methods that can sufficiently improve the acoustic characteristics. In addition, in the case of urea grease, from the viewpoint of long-term use, an improvement in the degree of centrifugal oil separation is also required.
The present invention provides a urea grease in which both the acoustic characteristics and the degree of centrifugal separation are improved when comparing greases of the same type and amount of base oil and thickener.

According to one aspect of the present invention, a mixture of a monoamine compound which is at least one of aliphatic monoamines and aromatic monoamines and a diisocyanate compound is subjected to shear at a minimum shear rate of 10 ² s ⁻¹ or more. A urea grease is provided which is characterized by being obtained by forming a thickener.

  According to the present invention, it is possible to provide a urea grease in which both the acoustic characteristics and the degree of centrifugal separation are improved when comparing greases in which the type and amount of base oil and thickener are the same.

BRIEF DESCRIPTION OF THE DRAWINGS In embodiment of this invention, the schematic sectional drawing which shows an example of the manufacturing apparatus of urea grease. The figure which shows the outline of a side, and the outline of an upper surface about the manufacturing apparatus of FIG. The figure which shows the outline of the side in the manufacturing apparatus of urea grease, and the outline of an upper surface in other embodiment of this invention. Schematic which shows the manufacturing method of the conventional urea grease.

[Urea grease]
Urea grease of the present embodiment (hereinafter, also referred to as "the grease.") Is a monoamine compound is at least one kind of the aliphatic monoamines and aromatic monoamine, a mixture of a diisocyanate compound, 10 ² s It is obtained by applying a shear at a minimum shear rate of ^-1 or more to cause a reaction. Hereinafter, the grease will be described in detail.
A mixed solution of a monoamine compound and a diisocyanate compound, which is at least one of an aliphatic monoamine and an aromatic monoamine, comprises a solution containing a monoamine compound in a base oil and a solution containing a diisocyanate compound in a base oil It becomes a liquid mixture by putting in a reaction vessel.
This grease is a urea grease in which a thickener is formed by reacting the above-mentioned mixed solution by giving a minimum shear rate of 10 ² s ⁻¹ or more.
Hereinafter, the grease will be described in detail.

(Base oil)
The base oil used in the present grease is not particularly limited, and examples thereof include mineral base oils and synthetic base oils used in general grease production. These can be used alone or as a mixture.
As the mineral oil-based base oil, one obtained by appropriately combining vacuum distillation, solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, sulfuric acid washing, clay refining, hydrorefining and the like can be used. Moreover, as synthetic base oils, polyalphaolefin (PAO) base oils, other hydrocarbon base oils, ester base oils, alkyl diphenyl ether base oils, polyalkylene glycol base oils (PAG), alkyl benzene bases Base oil etc. are mentioned. 40 ° C. The kinematic viscosity of the base oil is, 10 mm ² / preferably s or 600mm is ² / s or less, more preferably at most 20 mm ² / s or more 300 mm ² / s, 30 mm ² / s or more 100 mm ² / It is particularly preferable that it is s or less.

(Thickener)
The thickener used in the present grease is obtained by reacting a monoamine compound, which is at least one of an aliphatic monoamine and an aromatic monoamine, with a diisocyanate compound in a solution. In the present embodiment, the thickener is obtained by giving a minimum shear rate of 10 ² s ⁻¹ or more to the mixed solution at the time of reaction, from the viewpoint of achieving both acoustic characteristics and lubrication life. is necessary.
The aliphatic monoamine is not particularly limited and may be a chain type or an alicyclic type, but from the viewpoint of acoustic properties, a chain aliphatic monoamine is preferable. The carbon number of the chain aliphatic monoamine is preferably 6 or more and 24 or less, more preferably 6 or more and 20 or less, and particularly preferably 8 or more and 18 or less from the viewpoint of boiling point and solubility. The chain aliphatic monoamines include hexylamine, octylamine, dodecylamine, hexadecylamine, stearylamine and eicosylamine. These may be used alone or in combination of two or more.
Aromatic monoamines include tolylamine, aniline, and trimethylaniline, and the like. These may be used alone or in combination of two or more. Among these, tolylamine is preferred from the viewpoint of stability and safety.
Examples of the diisocyanate compound include diphenylmethane-4,4'-diisocyanate (MDI), tolylene diisocyanate, and naphthylene-1,5-diisocyanate. These isocyanates may be used alone, or a plurality of isocyanates may be mixed and used.

(Measurement value by FAG method)
In the present grease, it is preferable that the measured values by the FAG method satisfy the following conditions.
That is, the value obtained by measuring the level high 32-64s of the present grease according to the FAG method with respect to the present grease obtained by applying shear to the mixed liquid at a minimum shear rate of 10 ² s ⁻¹ or more and causing the reaction It is preferable that the ratio of V _S ) to the value (V _N ) obtained by measuring the Level High 32-64s of the urea grease produced by the conventional method satisfy the condition shown by the following equation.
V _S / V _N ≦ 0.9
The urea grease prepared by the conventional method is, for example, urea grease as described in (i) and (ii) below.
(I) Urea grease obtained by applying shear to the mixture at a minimum shear rate of less than 10 ² s ⁻¹ and reacting (ii) maximum shear rate (Max) and minimum shear rate (Min) for the mixture Urea grease obtained by reaction in such a way that the ratio (Max / Min) is 70 or more The maximum shear rate (Max) and the minimum shear rate (Min) will be described later.

Also, Peak High 32-64 s and Level High 32-64 s obtained according to the FAG method can be measured using a grease measuring instrument (Grease Test Rig Be Quiet +) manufactured by SKF. Specifically, an acoustic measurement dedicated bearing without grease is set in this acoustic measurement device, and while rotating at a predetermined speed, acoustic data from 32 seconds to 64 seconds after the start of rotation is obtained. Repeat this operation a total of six times without replacing the bearings. Further, a predetermined amount of sample (grease) is sealed in this bearing, and while rotating at a predetermined speed, acoustic data of 32 seconds after the start of rotation and 64 seconds after the start of rotation is obtained. Repeat this operation a total of six times without replacing the bearings. These are analyzed by a program built into the sound measurement instrument to obtain an average value of six measurements of Peak High and Level High.
Perform the same operation (6 times without grease filled, 6 times after grease filled) with another dedicated bearing and analyze with the program to obtain the average value as well. By obtaining the average value further from the average value measured by the two bearings, the values of Peak High and Level High can be obtained according to the FAG method.
Usually, in the FAG method, grease is sealed in a bearing and acoustic characteristics are evaluated using acoustic data from 32 seconds to 64 seconds after the first rotation. An acoustic peak may be observed, for example, due to the burst of air bubbles that may have been mixed in the grease from 32 seconds to 64 seconds after the first rotation. However, in a grease which is originally excellent in acoustic characteristics, the acoustic characteristics are unfavorably badly evaluated if a peak which is considered to be derived from bubble burst is generated. Even if it measures repeatedly by n = 3-5, an acoustic characteristic value with high reproducibility is not often obtained. Therefore, in the present invention, six measurements were performed with one dedicated bearing in order to improve the point. The peak that is considered to be derived from bubble bursting decreases after the second rotation, and by adopting the average value, good reproducible data can be obtained.

  In addition, as a means to make Peak High 32-64s and Level High 32-64s into the above-mentioned range according to FAG method, it is greased, for example, giving high shear uniformly like a manufacturing method of this grease mentioned below. Methods are included.

(Additive)
The grease may further contain various additives. Such additives include antioxidants, extreme pressure agents, and rust inhibitors.
Examples of antioxidants include amine-based antioxidants such as alkylated diphenylamine, phenyl-α-naphthylamine and alkylated-α-naphthylamine, 2,6-di-t-butyl-4-methylphenol, and 4, Phenolic antioxidants, such as 4-methylene bis (2, 6- di-t- butylphenol), etc. are mentioned. The preferable blending amount of these antioxidants is about 0.05% by mass or more and 5% by mass or less based on the total amount of the grease.

  Extreme pressure agents include zinc dialkyl dithiophosphates, molybdenum dialkyl dithiophosphates, ashless dithiocarbamates, zinc dithiocarbamates, thiocarbamic acids such as molybdenum dithiocarbamates, sulfur compounds (sulfurized fats and oils, sulfurized olefins, polysulfides, sulfided mineral oils, thiophosphorus Acids, thioterpenes, dialkylthiodipyropionates, etc.), phosphoric acid esters, phosphites (tricresyl phosphate, triphenyl phosphite, etc.), etc. may be mentioned. The preferable blending amount of the extreme pressure agent is about 0.1% by mass or more and 5% by mass or less based on the total amount of the grease.

Antirust agents include benzotriazole, zinc stearate, succinic acid esters, succinic acid derivatives, thiadiazole, benzotriazole, benzotriazole derivatives, sodium nitrite, petroleum sulfonate, sorbitan monooleate, fatty acid soap, amine compounds, etc. It can be mentioned. The preferable blending amount of the rust preventive agent is about 0.01% by mass or more and 10% by mass or less based on the total amount of the grease.
The various additives as described above may be blended singly or in combination of several types.

[Method of producing urea grease]
The present grease can be produced, for example, by the method for producing the present grease described below (hereinafter, also referred to as "the present production method"). In this production method, a base oil 1 containing a monoamine compound and a base oil 2 containing a diisocyanate compound are mixed liquid, and a minimum shear rate of 10 ² s ⁻¹ or more is given to the mixed liquid. That is, after the base oil 1 and the base oil 2 are placed in the reaction vessel, high speed shear is instantaneously imparted to the mixture. Then, while the monoamine compound and the diisocyanate compound are mixed and dispersed, they are reacted to form a thickener. Hereinafter, the present manufacturing method will be described in detail.

(Base oil)
The base oil 1 and the base oil 2 used in the present manufacturing method are not particularly limited, and the base oil used in the present grease can be used.
In view of the compatibility between the base oil 1 and the base oil 2, it is preferable to have similar polarity and further similar viscosity characteristics. Therefore, it is most preferable that the base oil 1 and the base oil 2 use the same base oil.

(Thickener)
In this production method, a thickener is formed from the monoamine compound and the diisocyanate compound.
As the monoamine compound and the diisocyanate compound, those used in the present grease can be used.
These diisocyanate compounds and monoamine compounds are continuously introduced into a reaction vessel (grease manufacturing apparatus) at a molar ratio of 1: 2, and, as described later, large dams are generated by mixing and reacting while giving high shear. It is possible to produce difficult diurea grease. In addition, a mixture of the diisocyanate compound and the monoamine compound described above is continuously introduced into the reaction vessel (grease manufacturing apparatus) so that the isocyanate group and the amino group become equal, and mixing and reaction are similarly performed while giving high shear. By doing this, it is possible to produce urea grease which is hard to form large lumps.

(Production method of grease)
In this production method, a base oil 1 containing a monoamine compound and a base oil 2 containing a diisocyanate compound are mixed liquid, and a minimum shear rate of 10 ² s ⁻¹ or more is given to this mixed liquid. That is, after the base oil 1 and the base oil 2 are placed in the reaction vessel, it is more important to apply high-speed shear to the mixture as instantaneously as possible than from the viewpoint of suppressing formation or coarsening of the lump.
Specifically, the time from when the base oil 1 and the base oil 2 are put in the reaction vessel to the application of the above-mentioned shear rate is preferably within 15 minutes, and more preferably within 5 minutes, It is particularly preferred that it is within 10 seconds. As the time is shorter, the reaction starts after the monoamine compound and the diisocyanate compound are well mixed and dispersed, so that the bundle of thickener molecules does not become thick and the size does not increase.

In addition, the minimum shear rate to be applied to the above-mentioned mixed solution is 10 ² s ⁻¹ or more as described above, preferably 10 ³ s ⁻¹ or more, and more preferably 10 ⁴ s ⁻¹ or more . The higher the shear rate, the better the dispersed state of the monoamine compound and diisocyanate compound, and the thickener formed, and a more uniform grease structure. That is, the bundle of thickener molecules does not become thick, and the size does not increase.
However, it is preferable that the minimum shear rate given to the above-mentioned liquid mixture is 10 < ⁷ > s <^-1> or less from the viewpoint of the safety | security of an apparatus, heat generation by shear etc., and its heat removal.
The shear rate can be applied, for example, by introducing the mixture into a reaction vessel that generates shear by relative motion between opposing wall surfaces.

As an apparatus (reaction container) for producing a grease capable of generating a high shear rate, for example, an apparatus having a structure as shown in FIG. 1 can be mentioned. FIG. 2 shows both the outline of the side and the outline of the top of the manufacturing apparatus of FIG.
The manufacturing apparatus shown in FIG. 1 has a structure capable of mixing high-speed shear uniformly in an extremely short time while mixing two types of base oils. High-speed shear is imparted to the mixture by the gap (gaps a, b) between the high-speed rotating part and the inner wall of the reaction vessel. The high-speed rotating portion may have a constant diameter in the rotation axis direction (a = b) and may have a different gap. Such a gap is adjusted by changing the diameter of the high speed rotating part in the direction of the rotation axis, or by making the high speed rotating part frusto-conical and moving the high speed rotating part up and down with respect to the inner wall of the reaction container provided with a taper. You may
Furthermore, the extrusion capability may be provided by forming a portion with a large gap into a continuously inclined screw or spiral shape.
Moreover, although FIG. 3 shows the reaction container (apparatus for manufacturing grease) of an aspect different from that of FIG. 1, the portions having different gaps are disposed in the rotational direction. In the case of this manufacturing apparatus, it is possible to provide a screw-like extrusion capability by inclining the portion having a large gap with respect to the rotation axis.

Here, the highest shear rate (Max) is the highest shear rate applied to the mixture, and the lowest shear rate (Min) is the lowest shear rate applied to the mixture For example, taking the reaction vessel described in FIG. 1 as an example, it is defined as follows.
Max = (Linear velocity of the high-speed rotating part surface at the portion where the gap between the high-speed rotating part surface and the container inner wall surface is minimized / relevant gap)
Min = (Linear velocity of the high speed rotating part surface at the portion where the gap between the high speed rotating part surface and the container inner wall surface is maximum / relevant gap)
In FIG. 1, the gap in the calculation of Max is a, and the gap in the calculation of Min is b. And if it is a reaction container of the type of FIG. 1, the value of ratio (Max / Min) will become small, if a high-speed rotation part is cylindrical form with a uniform diameter up and down.
On the other hand, as shown in FIG. 4, in the case of the conventional reaction container in which the high-speed rotating portion is disk-shaped or propeller-shaped (stirring blade), the gap in the calculation of Max is e, and the gap in the calculation of Min Is f. Then, since the value of the gap f is large, the value of Min becomes low and becomes 10 ² s ⁻¹ or less. That is, the above-mentioned mixed solution is sheared at a minimum shear rate of less than 10 ² s ⁻¹ and urea grease obtained by reaction is a conventional reaction container whose high-speed rotating part is disk-shaped or propeller-shaped. It is the urea grease obtained by making it react.
Also, the value of the ratio (Max / Min) is increased to 70 or more. In other words, the urea grease obtained by reacting it so that the ratio (Max / Min) of the maximum shear rate to the minimum shear rate to the above-mentioned mixed solution is 70 or more is that the high-speed rotating portion has a disk shape or propeller shape. It is a urea grease obtained by reacting in a conventional reaction vessel.

Therefore, in the present production method, the ratio (Max / Min) of the maximum shear rate (Max) to the minimum shear rate (Min) in the shear applied to the mixture in the reaction vessel described above is preferably 50 or less. It is more preferably 20 or less, still more preferably 10 or less, and particularly preferably 5 or less. Since the shear rate with respect to the liquid mixture is as uniform as possible, a lump does not become coarse and a uniform grease structure is obtained.
As described above, since Max / Min is preferably small, ideally a = b. That is, in the case of the reaction vessel of the type shown in FIG. 1, it is most preferable that the high-speed rotating part be cylindrical with a uniform diameter in the upper and lower directions.
In addition, when manufacturing urea grease, as a manufacturing apparatus, a structure like FIG. 3 may be sufficient.

  The present manufacturing method can be applied to any method of manufacturing a grease including the steps of placing a solution consisting of base oil 1 and a monoamine compound and a solution consisting of base oil 2 and a diisocyanate compound in a reaction vessel. Although the temperature conditions at the time of producing a thickener differ depending on the precursor to be used, when producing urea as a thickener, about 50 degreeC or more and 200 degrees C or less are preferable. When the temperature is 50 ° C. or more, the isocyanate is easily dissolved in the base oil, and when the temperature is 200 ° C. or less, deterioration of the base oil can be sufficiently suppressed. The solution temperature of the base oil and the amine before the introduction of the reaction vessel is preferably about 50 ° C. to 100 ° C., more preferably 60 ° C. to 90 ° C.

[Post-step in the method for producing urea grease]
In the present production method, the grease obtained by the above-described production method may be further kneaded. A roll mill generally used in grease production can be used for this kneading. The above-mentioned grease may be passed through a roll mill more than once.
Further, in the present manufacturing method, the grease obtained by the above-described manufacturing method may be further heated to a temperature of 70 ° C. or more and 250 ° C. or less. At a heating temperature of 250 ° C. or more, the base oil tends to deteriorate. The heating time at this time is preferably 30 minutes or more and 2 hours or less. Furthermore, in order to heat uniformly, you may knead | mix and stir. Note that a heating furnace or the like may be used at the time of heating.

Hereinafter, the present invention will be described in more detail by way of examples and comparative examples, but the present invention is not limited to these contents. Specifically, urea grease was manufactured under various conditions shown below, and the properties of the obtained grease were evaluated.
Example 1
The grease was manufactured by a urea grease manufacturing apparatus of the type shown in FIG. The specific manufacturing method is as follows.
PAO Keimotoyu heated to 70 ° C. (40 ° C. kinematic viscosity 63mm ² /s,MDI:6.98 wt% content) and, PAO Keimotoyu (40 ° C. kinematic viscosity heated again to 70 ° C. 63 mm ² / s, 216,000S and octylamine 18.4 wt% content) respectively flow 325 mL / min, was introduced continuously into the manufacturing apparatus in 120 mL / min, immediately the high-speed rotation portion, to a mixture at the gap passage ^- A maximum shear rate of ¹ was given. In addition, the lowest shear rate (Min) in passing the gap is 210,000 s ⁻¹ and the ratio (Max / Min) of the highest shear rate (Max) to the lowest shear rate (Min) in passing the gap is 1.03. Met. Also, the time from the mixing of the two solutions described above to the application of the maximum shear rate to the mixture was about 3 seconds. The grease discharged from the manufacturing apparatus was placed in a container preheated to 60 ° C., stirred at 250 rpm and immediately heated to 120 ° C. and held for 30 minutes, then heated to 160 ° C. and held for 1 hour. Thereafter, the mixture was allowed to cool while maintaining the stirring, and a roll mill was applied twice to obtain a grease. The amount of thickener obtained is 10% by mass with respect to the total amount of grease.

Comparative Example 1
Urea grease was prepared in the usual manner. Specifically, as shown in FIG. 4, the temperature is 60 ° C. with respect to a PAO-based base oil (containing 40 ° C. dynamic viscosity 63 mm ² / s, containing 9.09% by mass MDI) stirred with a stirring blade and kept at 60 ° C. of PAO Keimotoyu (40 ° C. kinematic viscosity of 63 mm ² / s, octylamine 12.4 wt% containing) was added dropwise. After the amine solution was dropped, the temperature was raised to 160 ° C. with stirring, and held for 1 hour. Thereafter, the mixture was allowed to cool while being stirred, and a roll mill was applied twice to obtain a grease. The amount of thickener obtained is 10% by mass with respect to the total amount of grease.
The maximum shear rate (Max) and the minimum shear rate (Min) during production are 100s ⁻¹ and 1.23s ⁻¹ respectively, and the maximum shear rate (Max) and the minimum shear rate (Min) during gap passage The ratio of (Max / Min) was 81.

Example 2
In Example 1, the 500N mineral oil heated to 70 ° C. (40 ° C. kinematic viscosity 90mm ² /s,MDI7.49 wt% content), 500N mineral oil (40 ° C. kinematic viscosity heated likewise to 70 ℃ 90mm ² / s And octylamine (containing 14.7% by mass) at a flow rate of 300 mL / min and 204 mL / min, respectively, in the same manner except that a maximum shear rate of 21,000 s ⁻¹ was applied. I got grease. The amount of thickener obtained is 10% by mass with respect to the total amount of grease.
The lowest shear rate (Min) during gap passage is 20,400 s ⁻¹ , and the ratio (Max / Min) of the highest shear rate (Max) to the lowest shear rate (Min) during gap passage is 1.03. Met.

Comparative Example 2
A grease was obtained in the same manner as in Comparative Example 1 except that the base oil was changed to 500 N mineral oil (40 ° C. kinematic viscosity is 90 mm ² / s). The amount of thickener obtained is 10% by mass with respect to the total amount of grease.
The maximum shear rate (Max) and the minimum shear rate (Min) during production are 100s ⁻¹ and 1.23s ⁻¹ respectively, and the maximum shear rate (Max) and the minimum shear rate (Min) during gap passage The ratio of (Max / Min) was 81.

[Example 3]
In Example 1, the base oil heated to 70 ° C. is ester-based synthetic oil (containing 40 ° C. kinematic viscosity 33 mm ² / s, containing 10.9 mass% MDI), and the ester-based synthetic oil (40 ° C.) similarly heated to 70 ° C. A grease was obtained in the same manner, except that dynamic viscosity was 33 mm ² / s and containing 28.9 mass% of tolylamine was continuously introduced into the production apparatus at a flow rate of 325 mL / min and 100 mL / min, respectively. The amount of thickener obtained is 15% by mass with respect to the total amount of grease.
The minimum shear rate (Min) during gap passage is 210,000 s ⁻¹ , and the ratio (Max / Min) of the maximum shear rate (Max) to the minimum shear rate (Min) during gap passage is 1.03. Met.

Comparative Example 3
In Comparative Example 1, an ester-based synthetic oil (40 ° C. dynamic viscosity maintained at 60 ° C.) was used for the ester-based synthetic oil maintained at 60 ° C. (40 ° C. kinematic viscosity 33 mm ² / s, containing 14.3 mass% MDI). A grease was obtained in the same manner as described above except that the viscosity was 33 mm ² / s and 15.9% by mass of tolylamine was added dropwise. The amount of thickener obtained is 15% by mass with respect to the total amount of grease.
The maximum shear rate (Max) and the minimum shear rate (Min) during production are 100s ⁻¹ and 1.23s ⁻¹ respectively, and the maximum shear rate (Max) and the minimum shear rate (Min) during gap passage The ratio of (Max / Min) was 81.

<Evaluation of grease>
Grease evaluation (mixed penetration, centrifugal oil removal, Peak High 32-64 s, Level High 32-64 s) was performed by the following method. The obtained results are shown in Table 1. Table 1 also shows the maximum shear rate, the ratio of the maximum shear rate (Max) to the minimum shear rate (Min) (Max / Min), and the amount of thickener at the time of production of each grease.
(1) Mixed penetration The mixed penetration was measured by the method according to the description of JIS K2220.
(2) Centrifugal oil separation degree The centrifugal oil separation degree when 20g of grease is put as a sample in a centrifugal separation tube using a centrifugal separator and an acceleration of 16,000 G is applied for 3 hours at 20 ° C is determined by the following equation. The
Centrifugal oil separation (% by weight) = (weight of oil separated / weight of prepared grease) × 100
(3) Peak High 32-64s and Level High 32-64s
It can be measured using an grease measuring instrument (Grease Test Rig Be Quiet +) manufactured by SKF. Specifically, an acoustic measurement dedicated bearing without grease is set in this acoustic measurement device, and while rotating at a predetermined speed, acoustic data from 32 seconds to 64 seconds after the start of rotation is obtained. Repeat this operation a total of six times without replacing the bearings. Further, a predetermined amount of sample (grease) is sealed in this bearing, and while rotating at a predetermined speed, acoustic data of 32 seconds after the start of rotation and 64 seconds after the start of rotation is obtained. Repeat this operation a total of six times without replacing the bearings. The values of Peak High and Level High are obtained by analyzing these with a program built in the sound measurement device.
Perform the same operation (6 times without grease filled, 6 times after grease filled) with another dedicated bearing and analyze with the program to obtain the values of Peak High and Level High.
The average of the two sets of Peak High and Level High values obtained with the two bearings is obtained by averaging them.

As shown in Table 1, the ratio (V _S / V _N ) between the value V _S of Level High 32 to 64 s of Example 1 and the value V _N of Level High 32 to 64 s of Comparative Example 1 is 0.86. It is. Similarly, the ratio (V _S / V _N ) in Example 2 and Comparative Example 2 is 0.89, and the ratio (V _S / V _N ) in Example 3 and Comparative Example 3 is determined. , 0.76. That is, the urea greases of Examples 1 to 3 satisfy the condition that the ratio (V _S / V _N ) is 0.9 or less.
And when Examples 1-3 and Comparative Examples 1-3 are compared, respectively, the urea grease of Examples 1-3 has an acoustic characteristic, although the kind and quantity of a base oil and a thickener are the same. It was confirmed that the urea grease was improved in both the centrifugal oil and the centrifugal oil separation.
The present invention includes the following aspects.
[1]
A mixture solution of a monoamine compound, which is at least one of aliphatic monoamines and aromatic monoamines, and a diisocyanate compound is sheared at a minimum shear rate of 10 ² s ⁻¹ or more to form a thickener. Urea grease characterized by being obtained by
[2]
In the urea grease described in [1] above,
A value (V _S ) obtained by measuring Level High 32 to 64 s of the urea grease according to the FAG method ,
The ratio of the value obtained by measuring the Level High32-64s urea grease obtained by reacting giving shear at the lowest shear rate of less than ¹⁰ 2 ^{s -1} to the mixed solution _{(V N)} is,
V _S / V _N ≦ 0.9
Urea grease characterized by satisfying.
[3]
In the urea grease described in [1] above,
A value (V _S ) obtained by measuring Level High 32 to 64 s of the urea grease according to the FAG method ,
Measured value of Level High 32-64s of urea grease obtained by making the ratio (Max / Min) of the maximum shear rate (Max) to the minimum shear rate (Min) to the mixture liquid be 70 or more The ratio to V _N ) is
V _S / V _N ≦ 0.9
Urea grease characterized by satisfying.
[4]
In the urea grease according to any one of the above [1] to [3],
The liquid mixture is a mixture of the base oil 1 containing the monoamine compound and the base oil 2 containing the diisocyanate compound.
Urea grease characterized by
[5]
In the urea grease according to any one of the above [1] to [4],
The aliphatic monoamine is a chain aliphatic monoamine having 6 to 20 carbon atoms.
Urea grease characterized by
[6]
In the urea grease according to any one of the above [1] to [5],
The aliphatic monoamine is octylamine
Urea grease characterized by
[7]
In the urea grease according to any one of the above [1] to [4],
The aromatic monoamine is tolylamine
Urea grease characterized by
[8]
In the urea grease according to any one of the above [1] to [7],
The minimum shear rate is less than 10 ⁷ s ⁻¹
Urea grease characterized by

Claims (6)

A base oil containing a monoamine compound which is at least one of a chain aliphatic monoamine and an aromatic monoamine, and a base oil containing a diisocyanate compound are introduced into a production apparatus for producing a grease, and a mixed liquid is prepared. age,
In the production apparatus, apply shear to the mixture at a minimum shear rate of 10 ² s ⁻¹ or more within 15 minutes,
A method for producing a grease, which comprises reacting while mixing and dispersing the monoamine compound and the diisocyanate compound to obtain a thickener. The method for producing a grease according to claim 1, wherein the chain aliphatic monoamine is a chain aliphatic monoamine having 6 to 20 carbon atoms . The method for producing a grease according to claim 1, wherein the chain aliphatic monoamine is octylamine.   The method for producing a grease according to any one of claims 1 to 3, wherein the aromatic monoamine is tolylamine. The method for producing a grease according to any one of claims 1 to 4, wherein the minimum shear rate is 10 ⁷ s ^-1 or less. The grease according to any one of claims 1 to 5, wherein the ratio (Max / Min) of the maximum shear rate (Max) to the minimum shear rate (Min) in the shear rate applied to the mixed solution is 50 or less. Method.

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