JPH03190996A - Production of grease having excellent acoustic property - Google Patents

Abstract

PURPOSE:To obtain a grease suitable for bearing having small diameter, etc., having noise-suppressing property by reacting a base oil dissolving or dispersing an isocyanate with a base oil dissolving or dispersing an amine in a specific condition. CONSTITUTION:(A) A base oil dissolving or dispersing an isocyanate and (B) a base oil dissolving or dispersing an amine are respectively pressed at <=5kg/cm<2> (preferably 25-200kgf/cm<2>) and reacted by impinging mixing, or respectively pressed at 0.5-25kgf/cm<2> (preferably 1-5kgf/cm<2>) and reacted with introducing to a stirring wing in rotating to afford the aimed grease.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for producing a grease that has excellent low noise characteristics, which are required characteristics of a grease used in small diameter bearings.

(Prior Art) Several proposals have been made for methods of improving the acoustic characteristics of grease. In order to improve the acoustic properties of grease, it is first necessary to homogenize it microscopically. That is, it is required that the thickener component be dispersed as uniformly as possible in the grease. The next step is to remove impurities in the grease.

Greases are broadly classified into those whose thickener components are completely dissolved in the base oil and those whose thickener components are not completely dissolved due to temperature rise during the manufacturing process.

This also applies to urea grease that uses isocyanate and amine as thickener raw materials. Among these urea greases, a method for improving the acoustic characteristics of completely soluble ones is disclosed in Japanese Patent Application Laid-Open No. 63-16279 by the present applicant.
It is disclosed in Publication No. 0.

These ensured uniform dispersion of the thickener components by completely dissolving them, and also made it possible to remove foreign substances by passing through the mesh. On the other hand, regarding a method for improving the acoustic properties of materials that are not completely dissolved during the manufacturing process, it is essential to uniformly disperse the thickener component, and Japanese Patent Application No. 63153654 filed by the present applicant states that The effectiveness of milling at times is disclosed.

The same is true for soap-based greases that use carboxylic acids or oils and fats and alkali metal hydroxides or alkaline earth metal hydroxides as thickener raw materials, and those that completely dissolve will require uniform dispersion of the thickener components. It is also possible to remove impurities by passing through a mesh, but no method has been found to improve uniform dispersion of thickener components in lithium complex greases that do not dissolve completely.

(Problem to be Solved by the Invention) However, the low-noise properties required of recent greases have become even more stringent, and the acoustic characteristics of greases that do not completely dissolve during the manufacturing process are described in Japanese Patent Application No. 153,654/1983. Even the described methods are not yet satisfactory. This is thought to be because the dispersion of the thickener in the grease is largely determined during the reaction, that is, at the same time as the thickener micelles are formed, and there is a limit to the dispersion by the subsequent milling process.

Therefore, the problem to be solved by the present invention is to provide a method for improving the acoustic properties of a grease that does not completely dissolve during the manufacturing process, that is, to more uniformly disperse a thickener component in the grease.

(Means for Solving the Problems) As a result of intensive research to satisfy the above problems, the present inventors found that dispersion of the thickener component is extremely difficult if it is carried out at the same time as the formation of the thickener micelles. The conclusion was reached that it is effective. This is a method that incorporates the dispersion process of the thickener component into the reaction process. In other words, in the grease reaction process, in a reaction vessel, (a) pressurize each to 5 kgf/cyn2 or more and cause them to collision mix and react; or (b) each from 0.5 kgf/cm2 to 25 kg.
A patented manufacturing method characterized in that the material is pressurized to f/cm2 and introduced into a rotating stirring blade for reaction.

2. In a reaction vessel, an aqueous solution or dispersion of base oil in which carbonic acid or oil or fat is dissolved or dispersed and an alkali metal hydroxide or alkaline earth metal hydroxide, (a) 5 kgf / cm of each. Pressure is applied to the mixture, and the reaction mixture is caused to mix by impact, or (1) 0.5 kgf/cm2 to 25 kg each.
The present invention relates to a method for producing grease with excellent acoustic properties, which is characterized in that the grease is introduced into a rotating stirring blade under pressure of f/cm2 and reacted. In (a), each pressurization was set to 0.5 kgf/cm2 or more, but preferably 25 to 200 kgf/cm2, and also preferably 1 to 5 kgf/cm2 in (b).

In this way, pressurizing the reaction liquid to high pressure in the reaction container and causing collision mixing to cause the reaction, and pressurizing the reaction liquid to low pressure and introducing it into a rotating stirring blade to cause the reaction, are two methods of high-pressure foaming that have already been put into practical use in the polyurethane industry. This can be done successfully using equipment and low pressure foaming equipment. All of these reactions are carried out in a reaction vessel, preferably a vessel called a mixing head. A high-pressure foaming device collides and reacts a highly pressurized reaction liquid in a mixing head.In the polyurethane industry, this reaction liquid is discharged into a mold and the reaction proceeds in a short time within the mold. , mold the polyurethane resin by solidifying it. In the polyurethane industry, reaction and dispersion can proceed extremely effectively by using polyol and isocyanate I as raw materials, or by collision-mixing both liquids under high pressure to bring about molecular order contact. is the biggest feature.

A typical example of this high-pressure foaming device is RIM (Reac
tion injection molding).

Low-pressure foaming equipment has a stirring blade called an agitator installed in the mixing head, which rotates at high speed.
Polyol and isocyanate are introduced here. reaction·
The dispersion can also proceed very effectively by the mechanical stirring force of this agitator.

Next, although the use of high-pressure/low-pressure foaming equipment is widely applied not only to the polyurethane industry but also to the plastic industry, the present invention is unique and new in its application to the grease industry. Further, since the present invention relates to a reaction step in producing grease, there are no particular restrictions on the steps before and after the reaction step. In other words, the concentrations and temperatures of isocyanates, amines, fatty acids, and fats and oils relative to the base oil to be reacted, as well as the concentrations and temperatures of alkali metal hydroxides and alkaline earth metal hydroxides relative to water, can be set arbitrarily. The process of heating, stirring,
The kneading and milling equipment can also be set arbitrarily.

Furthermore, in the reaction step of producing grease, the present invention provides a method in which a base oil in which an isocyanate is dissolved or dispersed and a base oil in which an amine is dissolved or dispersed are heated in a reaction vessel at a rate of (a) each of 5 kgf/cm2. (b) 0.5 kgf/cm2 to 25 kg each
An aqueous solution of a base oil and an alkali metal hydroxide or an alkaline earth metal hydroxide in which a carboxylic acid or oil or fat is dissolved or dispersed is introduced into a rotating stirring blade under pressure at f/cm2 and reacted. The dispersion liquid is placed in a reaction container at (a) 5 kgf each.
/cm2 or more to react by colliding and mixing, or (b) 0.5 kgf /c+n" to 25k, respectively.
gf/cm2 and introduced into a rotating stirring blade for reaction; however, any device capable of reaction and dispersion under such conditions will meet the purpose of the present invention, and therefore a high-pressure foaming device may be used. Alternatively, it is also possible to use a device that is not called a low-pressure foaming device.

Furthermore, although this manufacturing method is very effective for greases that do not completely dissolve, this reaction process can also be applied to those that completely dissolve, i.e., all urea-based and soap-based greases. Of course there is.

In the present invention, any base oil that can be used as a grease base oil can be used, including mineral oil and synthetic oil, and there are no particular limitations. For example, mineral oils include paraffinic mineral oils, naphthenic mineral oils, and hydrorefined refined mineral oils. Synthetic oils include dioctyl sebacate,
Ester-based synthetic oils such as penquerythritol ester and dipentaerythritol ester, synthetic hydrocarbon oils such as poly-α-olefins, ether-based synthetic oils such as alkyldiphenyl ethers, silicone oils such as dimethyl silicone, etc. It is.

Further, the isocyanate is diphenylmethane-44' diisocyanate (MDl, These include aromatic amines such as p-chloroaniline and naphthylamine, aliphatic amines such as hexylamine, octylamine, decylamine, dodecylamine, hexadecylamine, octadecylamine, and eicosylamine, and alicyclic amines such as cyclohexylamine.

Carboxylic acids include caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, hehenic acid, etc., straight chain fatty acids, 12-hydroxystearic acid, 12-hydroxylauric acid, 16
- Hydroxy fatty acids such as hydroxypalmitic acid, sebacic acid, azelaic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, speric acid,
These include dicarboxylic acids such as undecanoic acid and dodecanoic acid, and polycarboxylic acids such as dimer acid and trimer acid.

Examples of fats and oils include animal fats and oils such as beef tallow and lard, vegetable oils such as castor oil, rapeseed oil, and coconut oil, and hydrogenated and further refined products thereof. Furthermore, the alkali metal hydroxide and alkaline earth metal hydroxide are lithium hydroxide.

These include sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, etc.

In addition, the grease manufactured using the wood manufacturing method may contain antioxidants, rust inhibitors, oil-based agents, anti-wear agents, extreme pressure agents,
Additives such as solid lubricants can be added.

Next, the present invention will be explained with reference to the drawings.

FIG. 1 schematically shows a high-pressure foaming device used in the present invention. As shown in the figure, a work tank 1 for isocyanate 1 to liquid, a work tank 2 for amine liquid and a circulation line, a diagonal shaft type axial piston pump 4 as a metering pump,
It consists of a mixing head 3 and hydraulic units 1-5. The reaction and dispersion according to the invention takes place within the mixing head.

Here, isocyanate liquid and amine liquid are liquids in which isocyanate is dissolved or dispersed in base oil, and amine liquid is liquid in which amine is dissolved or dispersed in base oil.
This is used when manufacturing urea-based grease. The following is
We will discuss the case of manufacturing urea-based grease, but when manufacturing soap-based grease, work tanks 1 and 2 are filled with liquids in which carboxylic acids or fats and oils are dissolved or dispersed in base oil, alkali metal hydroxides, or alkaline earths. A liquid prepared by dissolving or dispersing a similar metal hydroxide in water is prepared.

Circulate before starting the reaction. Both liquids are pressurized within the mixing head during circulation, but the control piston returns them to the circulation line without contact. During this circulation, the discharge amounts of both liquids are finely adjusted. During the reaction, the control piston operates and both pressurized liquids collide and mix vigorously in the mixing head chamber, and are discharged as a urea grease reactant.

The basic line of the low-pressure foaming device is the same as that of the high-pressure foaming device. However, there is no hydraulic unit as shown in Figure 1,
There is also a stirring blade called an agitator inside the mixing head, which rotates at high speed. During the reaction, both liquids are injected from the nozzle toward this agitator. At this time, both liquids are pressurized only by a pump, and are not at high pressure as in a high-pressure foaming device, but they are mixed vigorously by the rotation of an agitator and are discharged as a urea grease reactant.

The process of producing grease using this high-pressure foaming device is as follows.

Add the base oil and isocyanate compound to the isocyanate liquid work tank, and add the base oil and amine compound to the amine liquid work tank. At this time, depending on the requirements, 60~
Warm to 80°C. Next, the dissolved or dispersed isocyanate liquid and amine liquid are sealed to create an N2 gas atmosphere.

Then it circulates and warms the line. The amount of isocyanate liquid and amine liquid to be discharged from the metering port is determined so as to have an equal equivalent ratio, and the isocyanate liquid and amine liquid are collidingly mixed, that is, reacted and dispersed, with a mixing head at an arbitrary discharge pressure, and then discharged.

The discharged grease is in a liquid state when it passes through the nozzle, and its temperature is preferably 60 to 80°C before the two-phase reaction, but after discharge it immediately becomes a hardened block solid, and the temperature remains unchanged for several hours. The temperature continues to rise to 130-140°C. When this reactant was received in a container such as a drum, the temperature of the contents remained close to 100°C even after two days.

Furthermore, when producing grease using a low-pressure foaming device, the same procedure as in the case of a high-pressure foaming device was carried out.

3-4 The condition of the discharged grease was similar to that when a high-pressure foaming device was used.

Although these phenomena have not yet been established logically, they are estimated as follows.

When using a high pressure foaming device, 5kgf/Cm
2 or more hours, preferably 25 kgf/cm2 to 200 kgf
Both liquids pressurized to /cm2 pass through the orifice and become turbulent in the mixing head, where they collide and mix violently.

At this time, both the isocyanate and amine components are thought to come into contact on a molecular order and are discharged from the discharge port.

Since the contact time is short, the reaction is not yet completed at the time of discharge, and therefore the liquid is in a liquid state while waiting for discharge. However, the isocyanate and amine in the container are in contact on a molecular order, and the reaction proceeds even without stirring, and the temperature continues to rise due to the exothermic reaction. In this way, when the two phases are brought into contact on a molecular order during the reaction, the reactants, that is, the thickener particles, are dispersed in a form close to the molecular order. The hardness of grease largely depends on the shape of its thickener particles, and it is thought that this form of thickener in a form close to the molecular order exhibits the ultimate thickening ability, which explains why it becomes a block-shaped solid. .

In addition, when using a low-pressure foaming device, the high-speed rotation of the agitator enables contact on the molecular order.
It is thought that the same effect as when using a high-pressure foaming device was obtained.

As is clear from this actual phenomenon, when a high-pressure type or low-pressure type foaming device is applied, isocyanate-1 liquid and amine liquid are each pressurized to 5 kgf/cm2 or more, mixed by collision, and reacted. or 0.5 kgf each
/c+n2 to 25 kgf/cm2 and introduced into a rotating stirring blade and reacted, it is possible to bring both the isocyanium-+- and amine components into contact on the molecular order, and as a result, the urea thickener produced. It has become possible for agent particles to exist in grease in a form close to the molecular order. Furthermore, it is thought that in a grease using the Haas grease obtained in this manner, the thickener component is uniformly dispersed in the grease, and as a result, the grease can have excellent acoustic properties.

(Examples and Comparative Examples) The present invention will be specifically explained using Examples and Comparative Examples. The contents of Examples and Comparative Examples are shown in Table 1.2, and the test methods used here are as follows.

(a) Consistency Based on JIS K 222205.3 (b) Optical microscope observation of grease (100x magnification)
Test conditions: Bearing 608 Thrust load: 2 kgf Radial load: 150 gf Rotation speed: 1.80 Qrpm Grease filling amount: 0.35 ml Test time: 2 minutes A score (out of 100) is given based on the results of noise count and anzolone level.

The following base oils were used in Examples and Comparative Examples.

Evaluation A D E-----Viscosity at 40°C is 100cS
Alkyldiphenyl ether oil P A 0---Poly-alpha olefin oil having a viscosity of 100 cSt at 40°C Also, the method for preparing the grease used in Examples and Comparative Examples is shown below.

TD15.53kg in the work tank of the isocyanate liquid on the practical side
, put 18.75 kg of ADE, 5.95 h of paratoluidine, 1.02 kg of parachloroaniline, and 18.75 kg of ADE in the amine liquid work tank, and after heating both liquids to 70 to 80°C, reduce the discharge amount. The reaction was carried out using the high-pressure foaming apparatus shown in FIG. 1, which was adjusted to have an equal amount of reaction under the set pressure of 150 kgf/cm2 in both tanks. Since the reaction product became a block-like solid, it was kneaded to a hardness that could be used as a grease to obtain the urea grease of Example 1. The kneading device is a colloid mill manufactured by Freema (
A clearance of 300 μm between the rotor and the stake was used. Hereinafter, the colloid mill manufactured by Freema will be abbreviated as Freema Mill.

7 ] 8 Practical Example A urea grease of Example 2 was obtained in the same manner as in Example 1 except that the free mill was changed to a three-roll mill.

The reacted grease obtained in Example 1 was heated at a rate of 1° (:/min), held at 175°C ± 5°C for 30 minutes, and after cooling was heated in a freema mill (rotor-stake clearance 3
00 μm) to obtain the urea grease of Example 3.

Actual Fence Example No. L Urea grease of Example 4 was obtained in the same manner as in Example 3 except that the freemer mill of Example 3 was changed to a three-roll mill.

Akira Sashi - TDI4.77kg in the isocyanate liquid work tank
, put 19.64 kg of ADB, 5.08 kg of paratoluidine, 0.87 kg of parachloroaniline, and 19.64 kg of ADE into the amine liquid work tank.
I added g. Thereafter, the urea grease of Example 5 was obtained in the same manner as in Example 1.

Actual Journey Example” - TDI 3.94 kg in isocyanate liquid work tank
, put 20.55 kg of ADE, 4.24 kg of paratoluidine, 0.72 kg of parachloroaniline, 20.55 kg of ADE into the amine liquid work tank.
I put in kg. Thereafter, the urea grease of Example 6 was obtained in the same manner as in Example 1.

Urea grease of Example 7 was obtained in the same manner as in Example 1 except that the base oil of Example 1 was changed to PAO.

Mikikuko” - MDI5.3f1k in the isocyanate liquid work tank
g, A D E 20.00 kg, paratoluidine 4.62 kg in the amine liquid work tank, △D E
I put 20.00kg in it. Thereafter, the urea grease of Example 8 was obtained in the same manner as in Example 1.

T D I 5.53 kg, A D E 1.8 in the isocyanate-1 liquid work tank of the n-degree low-pressure foaming device.
．． Put 75kg of paratoluidine and 1.02kg of parachloroaniline into the amine liquid work tank.
, Add 18.75Kg of ADE and bring both liquids to 70~
After heating to 80°C, the reaction was carried out by adjusting the discharge amount so that an equal amount of reaction occurred. The discharge pressure of both liquids at this time is 2kgf/c
It was rR.

The reaction product became a block-like solid as in the case of using a high-pressure foaming device, so it was kneaded in a freema mill.

This JL (LL) In the first container, TDI (1-lylene diisocyanate)
5.53kg, A D Snake 1.8.75kg 7
Warmed to 0-80°C. 5.95 kg of paratoluidine and 1.02 kg of parachloroaniline in the second container =
18.75 kg of ADE was taken, heated to 70-80°C, added to the first container, and stirred. This is a conventional reaction method for producing urea grease, and is also described in Table 2 below as a conventional method. After the reaction, freemer mill (rotor and stator clearance 30
0 μm) to obtain urea grease of Comparative Example 1.

↓Exchange -% Grease after the reaction performed in Comparative Example 1 was heated at a rate of 1°C/min, held at 175 ± 5°C for 30 minutes, and after cooling was heated in a freemer mill (rotor-stator clearance 30
0 μm) to obtain Comparative Example 2 1/Agelise.

Urea grease of Comparative Example 3 was obtained in the same manner as in Comparative Example 2 except that the freemer mill of Comparative Example 2 was changed to a three-roll mill.

Kitakairan↓ Urea grease of Comparative Example 4 was obtained by carrying out the process of Comparative Example 2 using the formulation of Comparative Example 1 and using a Statenk mixer as a reaction apparatus.

Urea grease of Comparative Example 5 was obtained by changing the base oil of Comparative Example 1 to PAO and carrying out the process of Comparative Example 2.

1 2 24 As a result of the present example and comparative example, by introducing a high-pressure foaming device or a low-pressure foaming device into the reaction device, a high score of 70 points or more was obtained in the anzolone test, and the acoustic properties were significantly improved. In the examples, milling was carried out after the reaction in the foaming device, and this was used to make a bronch-like solid into a grease-like state. In comparison with the comparative example, it is clear that this improvement in acoustic properties is not due to the milling process, but is due to the reaction and dispersion effect by the foaming device.

It was also observed that when a temperature raising step was added after the reaction and dispersion using the foaming device, the sound characteristics were slightly improved, but this was also an effect of the reaction and dispersion using the foaming device.

In addition, as mentioned above, the reason for this quantitative ratio of acoustic characteristics is the homogeneous dispersion of the thickener component. The particle structure of is shown in FIGS. 2 and 3. -As can be seen, the grease of Example 1:
It is homogeneous, and there are no particles larger than 10 μm as seen in Comparative Example 1. This is the same in other Examples and Comparative Examples, and it is recognized that the use of the foaming device uniformly dispersed the thickener component and improved the acoustic properties.

(Effects of the invention) (i) A base oil in which isocyanate-1. is dissolved or dispersed and a base oil in which an amine is dissolved or dispersed are each pressurized to 5 kgf/cm2 or more in a reaction vessel, (b) 0.5 kgf 70m2 to 25kg each
2. Aqueous solution of base oil and alkali metal hydroxide or alkaline earth metal hydroxide in which carboxylic acid or oil or fat is dissolved or dispersed by pressurizing it to f/cm2 and introducing it into a rotating stirring blade. or (a) pressurize each dispersion liquid to 5 kgf/cm2 or more and react by colliding and mixing the dispersion liquid in a reaction container, or (b) 0.5 kgf 70 m2 to 25 kg each
The present invention, which is characterized in that it is pressurized to f/cm25 6 and introduced into a rotating stirring blade for reaction, ensures uniform dispersion of the thickener component compared to grease obtained by conventional manufacturing methods, and improves bearing performance. It has become possible to obtain a grease that can improve the acoustic characteristics of.

[Brief Description of the Drawings] Fig. 1 is a layout diagram showing the outline of a high-pressure foaming device used in the method of the present invention; Fig. 2 is an optical micrograph showing the particle structure of the urea grease of Example 1; FIG. 3 is an optical micrograph showing the particle structure of the urea grease of Comparative Example 1. 1...Isocyanate liquid work tank 2...Amine liquid work tank 3...Mixing head 4...Pump 5...
hydraulic unit. 7

Claims (1)

[Claims] 1. In a reaction vessel, a base oil in which isocyanate is dissolved or dispersed and a base oil in which amine is dissolved or dispersed are each pressurized to 5 kgf/cm^2 or more and collided. Mix and react, or (b) 0.5 kgf/cm^2 to 25 kgf, respectively.
A method for producing grease with excellent acoustic properties, which comprises pressurizing the grease to /cm^2 and introducing it into a rotating stirring blade to cause a reaction. 2. An aqueous solution or dispersion of base oil in which carboxylic acid or oil or fat is dissolved or dispersed and alkali metal hydroxide or alkaline earth metal hydroxide in a reaction vessel, (a) 5 kgf/cm^ of each 2 or more to react by colliding and mixing, or (b) 0.5 kgf/cm^2 to 25 kgf each.
A method for producing grease with excellent acoustic properties, which comprises pressurizing the grease to /cm^2 and introducing it into a rotating stirring blade to cause a reaction. 3. The method for producing grease according to claim 1 or 2, characterized in that a mixing head is used as the reaction vessel.