JP2892066B2 - Manufacturing method of grease with excellent acoustic characteristics - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing grease having excellent performance in low noise characteristics, which is a required characteristic of grease used for small-diameter bearings and the like.

(Prior Art) Several methods have been proposed for improving the acoustic characteristics of grease. In order to improve the acoustic characteristics of grease, first, it is necessary to homogenize the grease microscopically. That is, it is required to disperse the thickener component as uniformly as possible in the grease. Next, removal of foreign matter in the grease can be mentioned.

During the manufacturing process, grease is roughly classified into those in which the thickener component is completely dissolved in the base oil depending on the temperature rise, that is, the temperature.

This is also true for urea greases using isocyanates and amines as thickener materials. A method of improving the acoustic characteristics of the urea grease which is completely dissolved is disclosed in JP-A-63-162790 by the present applicant. These ensured uniform dispersion of the thickener component by complete dissolution, and also enabled removal of foreign matter by passing through a mesh. On the other hand, with respect to a method for improving the acoustic properties of a material which does not completely dissolve during the manufacturing process, it has been a proposition to uniformly disperse the thickener component. Japanese Patent Application No. 63-153654 filed by the present applicant discloses a reaction. The effectiveness of milling at the end of the process is disclosed.

The same applies to soap-based greases that use carboxylic acids or fats and alkali metal hydroxides or alkaline earth metal hydroxides as raw materials for thickeners. Although it is possible to remove contaminants by passing through a mesh, it is not possible to improve the uniform dispersing of thickener components of those which do not completely dissolve, for example, lithium complex grease.

(Problems to be Solved by the Invention) However, the low noise required for recent greases has become even more severe, and the acoustic characteristics of grease that does not completely dissolve during the manufacturing process are described in Japanese Patent Application No. 63-153654. The described method has not been satisfactory. This is considered because the dispersion of the thickener of the grease is largely determined at the same time as the reaction, that is, at the time of forming the micelle of the thickener, and there is a limit to the dispersion by the subsequent milling treatment.

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

(Means for Solving the Problems) As a result of intensive studies to satisfy such problems, the present inventors have found that dispersion of the thickener component is extremely difficult if it is performed simultaneously with the formation of the thickener micelle. To be effective. This is a method in which the dispersion step of the thickener component is incorporated in the reaction step, that is, in the reaction step of grease, 1. The base oil in which isocyanate is dissolved or dispersed and the base oil in which amine is dissolved or dispersed are reacted. in a vessel, (b), respectively, and pressurized to 25~200kgf / cm ^2, or to collide mixed reaction or, (b), ^{respectively, 0.5kgf / cm 2 ~25kgf / cm} 2 in a stirring blade in the pressurized rotating A method for producing grease having excellent acoustic characteristics, characterized by being introduced into and reacting with grease.

2. An aqueous solution or dispersion of a base oil obtained by dissolving or decomposing a carboxylic acid or a fat and an alkali metal hydroxide or an alkaline earth metal hydroxide in a reaction vessel, (a) 25 to 200 kgf / pressurized to cm ^2, collide mixture is reacted or acoustic properties, characterized in that the reaction is introduced into (b), respectively, a stirring blade in the pressurized rotating in 0.5kgf / cm ² ~25kgf / cm ² It relates to a method for producing excellent grease. In (a), pressurization is 25-20
0 kgf / cm ² , and also in (b), preferably 1 to 5 k
gf / cm ² .

As described above, the reaction solution is pressurized to a high pressure in the reaction vessel and subjected to collision mixing and reaction, and the reaction solution is pressurized to a low pressure and introduced into a rotating stirring blade to perform the reaction. Using a device and a low-pressure foaming device can be done successfully. All of these react in a reaction vessel, preferably a vessel called a mixing head. A high-pressure foaming device is a device that impinges and mixes a reaction solution pressurized to a high pressure in a mixing head and performs a reaction. In the polyurethane industry, this reaction solution is discharged into a molding die, and the reaction proceeds in the mold in a short time. The polyurethane resin is molded by solidification. In the polyurethane industry, polyols and isocyanates are used as raw materials.
The most characteristic feature is that the reaction and dispersion can proceed very effectively by performing molecular order contact.
RIM (Reaction In)
jection Molding).

In the low-pressure foaming apparatus, a stirring blade called an agitator is installed in a mixing head, and this is rotated at a high speed to introduce the polyol and the isocyanate therein. The reaction / dispersion can also proceed very effectively by the mechanical stirring force of the agitator.

Next, the use of the high-pressure / low-pressure foaming apparatus is widely applied not only to the polyurethane industry but also to the plastics industry, but the application to the grease industry is unique to the present invention and is novel. Further, the present invention relates to a reaction step in producing grease, and steps before and after the reaction are not particularly limited. That is, the concentration and temperature of the isocyanate, amine and fatty acid and the fat and oil to be reacted with the base oil and the concentration and temperature of the hydroxide of the alkali metal and the hydroxide of the alkaline earth metal with respect to the water can be arbitrarily set. , Ie, heating, stirring, kneading, and a milling device can be arbitrarily set.

Further, the present invention provides, in a reaction step for producing grease, a base oil in which isocyanate is dissolved or dispersed and a base oil in which amine is dissolved or dispersed in a reaction vessel, (A) 25 to 200 kgf each. / cm ² pressurized, by impingement mixing is reacted or, (b), respectively, that react to introduce a stirring blade in the pressurized rotates in 0.5 kgf / cm ² ～25Kgf / cm ² and carboxylic acids or fats In a reaction vessel, an aqueous solution or dispersion of a base oil and an alkali metal hydroxide or an alkaline earth metal hydroxide in which the dissolved or dispersed base oil is dissolved, (a) each is pressurized to 25 to 200 kgf / cm ² , impingement mixing is allowed either by reaction or, (b), respectively, is characterized in that the reaction is introduced into the stirring blade in the pressurized rotating in ^{0.5kgf / cm 2 ~25kgf / cm 2} , · reaction under such conditions If it can be dispersed, a high pressure foaming device or low pressure Also under the designation of the device without the foam device that is available.

Further, while this method of manufacture is very effective for greases that do not completely dissolve, the reaction process is also applicable to those that completely dissolve, i.e., applicable to all urea-based and soap-based greases. Of course there is.

In the present invention, the base oil can be used irrespective of mineral oil or synthetic oil as long as it can be used as a grease base oil, and is not particularly limited. For example, mineral oils include paraffinic mineral oils, naphthenic mineral oils, and hydrorefined refined mineral oils. Examples of the synthetic oil include ester synthetic oils such as dioctyl sebacate, pentaerythritol ester, dipentaerythritol ester, synthetic hydrocarbon oils such as poly-α-olefin, and ether synthetic oils such as alkyl diphenyl ether. And silicone oils represented by dimethyl silicone.

Isocyanate is diphenylmethane-4,4 'diisocyanate (MDI), tolylene diisocyanate (T
DI), 3,3'dimethyldiphenyl 4,4 'diisocyanate (TODI) and the like, and the amine is an aromatic amine such as aniline, p-toluidine, p-chloroaniline, naphthylamine, hexylamine, octylamine, decylamine,
Aliphatic amines such as dodecylamine, hexadecylamine, octadecylamine and eicosylamine; and alicyclic amines such as cyclohexylamine.

Examples of the carboxylic acid include linear fatty acids such as caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, and behenic acid, 12-hydroxystearic acid, 12-hydroxylauric acid, 16-hydroxypalmitic acid, and the like. Dicarboxylic acids such as hydroxy fatty acids, sebacic acid, azelaic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, undecandioic acid, dodecandioic acid, and other dimer acids and trimer acids And the like. Examples of oils and fats include animal oils and fats such as beef tallow and lard, vegetable oils such as castor oil, rapeseed oil and coconut oil, and hydrogenated and further refined oils. The alkali metal hydroxide and alkaline earth metal hydroxide include lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide and the like.

Further, additives such as an antioxidant, a rust inhibitor, an oil agent, an abrasion resistance, an extreme pressure agent, and a solid lubricant can be added to the grease produced by the production method as required.

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

FIG. 1 schematically shows a high-pressure foaming apparatus used in the present invention. As shown in the figure, a work tank 1 for an isocyanate solution, a work tank 2 for an amine solution and a circulation line, and a diagonal axial piston pump 4 as a metering pump,
It comprises a mixing head 3 and a hydraulic unit 5.
The reaction and dispersion according to the present invention are performed in a mixing head.

Here, the isocyanate liquid and the amine liquid are liquids in which isocyanate is dissolved or dispersed in base oil, and the amine liquid is the liquid in which amine is dissolved or dispersed in base oil. That is when you do. The following describes the case of producing urea-based grease, but in the case of producing soap-based grease, a liquid obtained by dissolving or dispersing a carboxylic acid or a fat or oil in a base oil, a hydroxide of an alkali metal in work tanks 1 and 2 respectively. Alternatively, a liquid in which a hydroxide of an alkaline earth metal is dissolved or dispersed in water is charged.

Circulation is performed before the reaction. During the circulation, both liquids are pressurized in the mixing head, but return to the circulation line without contact by the control piston. During this circulation, fine adjustment of the discharge amount of both liquids is performed. During the reaction, the control piston is actuated, and the pressurized liquid is violently colliding and mixed in the chamber of the mixing head, and is discharged as a urea grease reactant.

The basic line of the low-pressure foaming apparatus is the same as that of the high-pressure foaming apparatus. However, the hydraulic unit as shown in FIG. 1 has a stirring blade called an agitator in the mixing head and rotates at high speed. During the reaction, both liquids are jetted from the nozzle toward this agitator. At this time, the two liquids are pressurized only by a pump and not at a high pressure as in a high-pressure foaming apparatus, but are vigorously mixed by rotation of an agitator and discharged as a urea grease reactant.

The grease manufacturing process using this high-pressure foaming apparatus is as follows.

The base oil and the isocyanate compound are added to the isocyanate liquid work tank, and the base oil and the amine compound are added to the amine liquid work tank. At this time, 60 ~
Heat to 80 ° C. Next, the dissolved or dispersed isocyanate liquid and amine liquid are sealed, and an N ₂ gas atmosphere is set.

Then circulate and warm the line. Determine the discharge amount so that the isocyanate liquid and the amine liquid have the same equivalent ratio from the measuring port,
At an arbitrary discharge pressure, the isocyanate liquid and the amine liquid are impact-mixed with a mixing head, that is, reacted and dispersed and discharged.

The discharged grease is liquid when passing through the nozzle,
The temperature is preferably 60-80 ° C. before the two-phase reaction, but immediately after being discharged, it becomes a cured block-like solid,
The temperature also continues to rise to 130-140 ° C over several hours.
When this reaction product was received in a container such as a drum, the temperature of the content was maintained at nearly 100 ° C. even after two days.

Grease was produced using a low-pressure foaming apparatus in the same manner as in the high-pressure foaming apparatus. The state of the discharged grease was the same as when the high-pressure foaming device was used.

Although these phenomena have not been theoretically established yet, they are presumed as follows.

In the case of using a high pressure foaming apparatus, the Ryoeki preferably 5 kgf / cm ² or more pressurized to ^{25kgf / cm 2 ~200kgf / cm 2} ,
After passing through the orifice, it becomes turbulent in the mixing head and violently collides and mixes. At this time, both components of the isocyanate and the amine are discharged from the discharge port on the assumption that they come into contact on the molecular order. Due to the short contact time, the reaction has not been completed yet at the time of discharge, and is therefore liquid in the state at the time of discharge. However, in the container, the isocyanate and the amine are in contact with each other on a molecular order, and the reaction proceeds even without stirring or the like, and the temperature continues to rise due to an exothermic reaction.
Thus, bringing the two phases into contact with each other at the molecular order during the reaction means that the reactant, that is, the thickener particles are dispersed in a form close to the molecular order. The hardness of grease depends largely on the form of the thickener particles, but the thickener form in the form close to this molecular order is considered to exhibit the ultimate thickening ability, which can explain the reason that it becomes a block-like solid. .

Also, when a low-pressure foaming device was used, it was considered that the same effect as when a high-pressure foaming device was used was obtained because the high-speed rotation of the agitator enabled contact on the order of molecules.

As is apparent from the actual behavior surfaces, respectively isocyanate solution and the amine solution as in the case of applying the high-pressure or low pressure foaming apparatus, or to 5 kgf / cm ² or more pressurized, by impingement mixing reaction or, each 0.5kgf / cm ² to 25kgf / cm ²
When pressure is applied to a rotating stirring blade to cause a reaction, both isocyanate and amine components can be brought into contact on the molecular order, and the resulting urea thickener particles are also greased in a form close to the molecular order. It was possible to make it exist inside. In addition, it is considered that the grease using the base grease obtained in this way can be a grease having excellent acoustic characteristics because the thickener component is uniformly dispersed in the grease.

(Examples and Comparative Examples) The present invention will be specifically described with reference to Examples and Comparative Examples.
In Examples, the contents of Comparative Examples are shown in Tables 1 and 2. Here, the test method is as follows.

(B) Consistency Based on JIS K 22220 5.3 (b) Optical microscope observation of grease (magnification: 100 times) (c) Bearing acoustic test The grease was tested with an Anderon meter.

Test conditions Bearing 608 Thrust load 2kgf Radial load 150gf Rotation speed 1800rpm Grease filling amount 0.35ml Test time 2min Evaluation Shown by the number of noises and Anderon level.

The following base oils were used as examples and comparative examples.

ADE: an alkyl diphenyl ether oil having a viscosity of 100 cSt at 40 ° C. PAO: a poly-α-olene fin oil having a viscosity of 100 cSt at 40 ° C. The method of adjusting the grease used in Examples and Comparative Examples is described below.

Example 1 5.53 kg of TDI, ADE1
Add 8.75 kg, add 5.95 kg of paratoluidine, 1.02 kg of parachloroaniline, and 18.75 kg of ADE to the amine liquid work tank.After heating both liquids to 70-80 ° C, set the discharge amount to 150 kgf / Adjust to equal reaction in cm ²
The reaction was performed using a high-pressure foaming apparatus shown in the figure. Since the reaction product became a block-like solid, it was kneaded to a hardness that can be used as grease to obtain the urea grease of Example 1. As a kneading apparatus, a colloid mill manufactured by Freema Co., Ltd. (the clearance between the rotor and the stator was 300 μm) was used. Less than,
Freema mill is abbreviated as Freema mill.

Example 2 A urea grease of Example 2 was obtained in the same manner except that the freema mill of Example 1 was changed to a three-roll mill.

Example 3 The grease after the reaction obtained in Example 1 was heated at a rate of 1 ° C./min, kept at 175 ° C. ± 5 ° C. for 30 minutes, and kneaded with a cooled freema mill (clearance between rotor and stator: 300 μm). The urea grease of Example 3 was obtained.

Example 4 A urea grease of Example 4 was obtained in the same manner as in Example 3 except that the freemer mill was changed to a three-roll mill.

Example 5 TDI 4.77 kg, ADE1
9.64 kg was added, and 5.08 kg of paratoluidine, 0.87 kg of parachloroaniline, and 19.64 kg of ADE were added to the amine liquid work tank. Hereinafter, the urea grease of Example 5 was obtained in the same manner as in Example 1.

Example 6 TDI 3.94 kg, ADE2
0.55 kg was added, and 4.24 kg of paratoluidine, 0.72 kg of parachloroaniline, and 20.55 kg of ADE were added to the work tank of the amine solution. Hereinafter, the urea grease of Example 6 was obtained in the same manner as in Example 1.

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

Example 8 TDI 5.38 kg, ADE2
0.002 kg, paratoluidine 4.62 kg and ADE 20.00 kg were added to the amine liquid work tank. Hereinafter, the urea grease of Example 8 was obtained in the same manner as in Example 1.

Example 9 A work tank for an isocyanate liquid in a low-pressure foaming apparatus was used.
5.53 kg of TDI, 18.75 kg of ADE, and 5.95 kg of paratoluidine and 1.02 K of parachloroaniline in the amine liquid work tank
g, 18.75 kg of ADE, and the mixture was heated to 70 to 80 ° C., and the reaction was carried out by adjusting the discharge amount so that the reaction became equivalent. The discharge pressure of both liquids at this time was 2 kgf / cm ² .

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

Comparative Example 1 In a first container, TDI (tolylene diisocyanate) 5.5
3kg and 18.75kg of ADE were added and heated to 70-80 ° C. 5.95 kg of paratoluidine, 1.02 k of parachloroaniline in the second container
g, 18.75 kg of ADE was heated to 70-80 ° C., added to the first vessel and stirred. This is a reaction method for producing urea grease which has been generally performed conventionally, and is described in Table 2 below as a conventional method. After the reaction, kneading was performed with a freemer mill (a clearance between the rotor and the stator of 300 μm) to obtain a urea grease of Comparative Example 1.

Comparative Example 2 The 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, cooled, and kneaded with a freemer mill (a clearance between the rotor and the stator of 300 μm). A urea grease of Comparative Example 2 was obtained.

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

Comparative Example 4 With the formulation of Comparative Example 1, the process of Comparative Example 2 was performed using a static mixer for the reactor to obtain a urea grease of Comparative Example 4.

Comparative Example 5 The base oil of Comparative Example 1 was changed to PAO and the process of Comparative Example 2 was performed to obtain a urea grease of Comparative Example 5.

As a result of this example and a comparative example, the introduction of a high-pressure foaming device or a low-pressure foaming device into the reactor resulted in a high score of 70 or more in the Anderon test, and markedly improved acoustic characteristics. In the embodiment, all the milling is performed after the reaction of the foaming apparatus, but this is used to make the block-like solid grease-like. In comparison with the comparative example, it is clear that the improvement of the acoustic characteristics is not due to the mill treatment, but to the effect of the reaction and dispersion by the foaming device. In addition, it was recognized that when the temperature raising step was added after the reaction / dispersion by the foaming device, the acoustic characteristics were slightly improved, but this was also an effect on the reaction / dispersion by the foaming device.

Although the reason for the improvement of the acoustic characteristics is that the thickener component is homogeneously dispersed as described above, optical micrographs (100 times) of the urea grease of Example 1 and Comparative Example 1 are representative examples of the urea grease. The particle structure is shown in FIG. 2 and FIG. As is apparent at first sight, the grease of Example 1 is:
It is homogeneous and does not have particles of 10 μm or more as seen in Comparative Example 1. This is the same in the other examples and comparative examples, and it can be seen that the use of the foaming device uniformly dispersed the thickener component and improved the acoustic characteristics.

(Effect of the Invention) 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 in a reaction vessel and subjected to collision mixing. is reacted or the (b), respectively, 0.5 kgf / cm ² to 25 kgf / cm ² was introduced into a stirring blade in the pressurized rotating it reacted to 2. base oil is dissolved or decomposed to carboxylic acids or fats An aqueous solution or dispersion of an alkali metal hydroxide or an alkaline earth metal hydroxide is charged in a reaction vessel to a pressure of 5 kgf / cm ² or more, and each of them is subjected to collision mixing and reaction, or ) respectively, by the present invention which comprises reacting by introducing a 0.5 kgf / cm ² to a stirring blade in the pressurized rotated in 25 kgf / cm ^2, compared with a grease obtained by conventional manufacturing methods, thickener A grease that guarantees uniform dispersion of components and improves the acoustic characteristics of bearings That it became possible.

[Brief description of the drawings]

FIG. 1 is a layout diagram schematically showing a high-pressure foaming apparatus 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, and FIG. 3 is Comparative Example 1. 4 is an optical micrograph showing a particle structure of urea grease of the present invention. 1. Work tank for isocyanate liquid 2. Work tank for amine liquid 3. Mixing head 4. Pump 5. Hydraulic unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C10N 10:04 40:14 50:10 70:00 (56) References Michihide Tokashiki, et al., “Tribology Series 8, Lubrication Grease” And Synthetic Lubricants "Published by Koshobo Co., Ltd. (1983-12-25), pp. 44, 54-66 (58) Fields investigated (Int. Cl. ⁶ , DB name) C10M 121 / 04,115,08 C10M 113 / 08,177 / 00 C10N 50:10

Claims (3)

(57) [Claims] 1. A base oil in which an isocyanate is dissolved or dispersed and a base oil in which an amine is dissolved or dispersed are pressurized to 25 to 200 kgf / cm ² in a reaction vessel, and the mixture is subjected to collision mixing to carry out reaction. or is (ii), respectively, 0.5 kgf / cm ² method for producing superior grease acoustic characteristics, characterized in that the reaction is introduced into ~25kgf / cm ² in a stirring blade in the pressurized rotating. 2. An aqueous solution or dispersion of a base oil obtained by dissolving or decomposing a carboxylic acid or a fat and an alkali metal hydroxide or an alkaline earth metal hydroxide in a reaction vessel. ~200kgf / cm ² pressurized, by impingement mixing is reacted or a comprises reacting by introducing into (b), respectively, a stirring blade in the pressurized rotating in 0.5kgf / cm ² ~25kgf / cm ² Method for producing grease with excellent acoustic characteristics. 3. The method for producing grease according to claim 1, wherein a mixing head is used as the reaction vessel.