JPH0737624B2 - Urea grease manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a urea grease having excellent mechanical stability, low thermosetting property, and excellent shear stability when containing water.

[Conventional technology]

As a conventional method for producing urea grease, there is a method for producing urea grease excellent in shear stability when containing water, which was previously proposed by the present applicant in Japanese Patent Laid-Open No. 59-124997.

[Problems to be solved by the invention]

However, in the above method, a diisocyanate is added to a part of the base oil to dissolve it, and an aromatic monoamine and an aliphatic monoamine are added to the rest of the base oil to dissolve and mix, and then both are mixed and reacted to produce a urea grease. The urea grease produced by this method is unsatisfactory in mechanical stability and thermosetting property, and there is an urgent need for improvement.

[Means for solving problems]

As a result of conducting a study for the purpose of improving the mechanical stability and decreasing the thermosetting property in order to solve such a problem, it is unavoidable to mix the aromatic monoamine and the aliphatic monoamine in the conventional production method described above. Without reacting the diisocyanate with the aromatic monoamine alone in the base oil at a temperature of 20 to 120 ° C, and separately reacting the diisocyanate with the aliphatic monoamine only in the base oil at a temperature of 20 to 120 ° C. After these reactions, the urea grease manufactured by the manufacturing method in which the mixed composition of both reaction products and the base oil is uniformly mixed at 60 to 150 ° C to manufacture urea grease is mechanically stable and thermosetting. Was found to be significantly improved.

Next, the urea grease thus obtained was added at 0.3 ° C / min.
A twisted micelle fiber structure is formed in the same manner as described in the above-mentioned Japanese Patent Publication by allowing the temperature to rise to 170 to 200 ° C. at the above temperature rising rate and further maintaining the temperature range for 0 to 180 minutes. The present invention has led to the present invention by finding that a urea grease having the above is obtained, and that the mechanical stability and the thermosetting property are remarkably improved and the shear stability when containing water is also excellent. That is, the present invention adds diisocyanate and aromatic monoamine to base oil
After keeping the temperature at 120 ℃ and reacting, separately adding diisocyanate and aliphatic monoamine to the base oil and keeping the temperature at 20 to 120 ℃ to react, both reaction compositions are kept at 60 to 150 ℃ and mixed uniformly. Of the urea grease having a twisted micellar fiber structure, which is characterized in that the temperature is raised to 170 to 200 ° C. at a temperature rising rate of 0.3 ° C. or more per minute, and the temperature is maintained for 0 to 180 minutes. The present invention relates to a manufacturing method.

[Work]

In the production method of the present invention, the diisocyanate and the aromatic monoamine are reacted only in the base oil to form a diurea compound having only an aromatic end group and dispersed in the base oil to form a grease, and the diisocyanate and the fat are separately added in the base oil. Diurea compound having only aliphatic end groups is generated by reacting with group monoamine only, dispersed in base oil to form a grease, and then both urea greases are kept at a temperature of 60 to 150 ° C to uniformly mix them. The gist lies in that it is a urea grease composition.

In the production method described in the above-mentioned Japanese Patent Laid-Open, since a diisocyanate, a mixture of an aromatic monoamine and an aliphatic monoamine are reacted in a base oil, a diurea compound having only an aromatic terminal group, a diurea having only an aliphatic terminal group. A compound and a diurea compound having an aromatic end group and an aliphatic end group are formed. Therefore, the grease obtained by such a method, in which the diurea compound is dispersed in the base oil, is clearly different from the urea grease of the present invention in the molecular structure of the thickener.

As a result of research, the inventors of the present invention only produced a diurea compound grease having only aromatic end groups and a diurea compound grease having only aliphatic end groups, and then mixing them in a specific mixing temperature range. It has been found that a desired urea grease having excellent mechanical stability and low thermosetting property can be obtained, which is a constitution and effect which cannot be easily corresponded from the prior application. Here, the mixing temperature range needs to be in the range of 60 to 150 ° C, which can also be known as a result of research. The reason why an excellent effect can be obtained only by such a manufacturing method has not been confirmed, but it is generally considered as follows.

In the case where a diurea compound having only an aromatic terminal group and a diurea compound having only an aliphatic terminal group coexist in the base oil in a dispersed state and the temperature range is 60 to 150 ° C. at a relatively low temperature, each diurea compound It is considered that the compound does not yet have a stable micelle structure, and both are mixed and reacted to form a complex. By stabilizing such a complexed micelle-structured composition by a high temperature treatment in the next step, a urea grease having the desired excellent properties can be obtained. When the mixing temperature is less than 60 ° C, the dispersion of each diurea compound is not uniform,
When the temperature exceeds 150 ° C., a stable micelle structure is mostly formed only by each diurea compound, so that no complex is formed and neither of the objects of the present invention can achieve the object. This mixing temperature
It is necessary to stir and mix uniformly at 60 to 150 ° C. Mixing time is usually 10 to 60 minutes. As a result, a complex micelle structure is obtained, and then the temperature of 170 to 200 ° C. is reached at a temperature rising rate of 0.3 ° C. or more per minute, whereby the micelle structure is almost twisted and stabilized.

Here, twisting is a phenomenon in which, when the grease is observed with an electron microscope, part or all of the ordinary ribbon-like or rod-like fiber structure is converted into a twisted fiber structure like a rope.

If the temperature rise rate is less than 0.3 ℃ / min, twisting will not occur and it is not appropriate. If the temperature is 0.3 ° C. or more per minute, twisting occurs at all temperatures, but in consideration of mass production, the preferable temperature is within the range of 0.3 to 5 ° C. per minute. The composition thus heated to raise the temperature was added to the above 170
When the temperature is kept in the temperature range of 200 ° C for 0 to 180 minutes, the twisting of the micelle structure is practically sufficient. Even if the holding time is 0, it is almost twisted, so there is no problem in practical use, but it is more preferable to apply a holding time of 30 to 180 minutes to complete the twisting. If it is longer than 180 minutes, the grease is oxidized, which is not preferable.

By carrying out such a temperature raising step and a temperature holding step, the water-containing shear stability can be remarkably improved. Also, it was confirmed that the twisted micelle fibers grow remarkably and become longer when the alcohol having 6 to 20 carbon atoms is added to the composition just before the temperature raising step and then the above step is passed.
It was also found that the grease in this state has further improved water-containing shear stability. When such an alcohol is added, the amount added is in the range of 0.3 to 3% by weight. Next, the composition after the temperature holding step is cooled, and other additives are added and kneaded at around room temperature to defoam to obtain a product.

The base oil used in the present invention is a refined mineral oil or a synthetic oil,
Diisocyanates are diphenylmethane-4,4'-diisocyanate, tolylene diisocyanate, naphthylene-
1,5-diisocyanate and the like, the aromatic monoamine is aniline, p-toluidine, naphthylamine and the like,
Aliphatic monoamines include hexylamine, octylamine,
Dodecylamine, hexadecylamine, eicosylamine and the like. The alcohol having 6 to 20 carbon atoms is n-hexanol, n-octanol, n-decanol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, eicosanol and the like.

Other additives include rust preventives such as N-alkyltrimethylene diamine dioleate and sorbitan dioleate, phenyl alpha naphthyl amine, antioxidants such as 2,6-ditertiarybutyl 4-methylphenol, and dialkyl dithiocarbamic acid. An extreme pressure additive such as molybdenum or zinc dialkyldithiophosphate may be added if necessary.

〔Example〕

The configurations and effects of the present invention will be specifically described with reference to Examples and Comparative Examples shown in Tables 1 and 2.

The test methods for the mechanical stability test, thermosetting test, and water-containing shear stability test described in Tables 1 and 2 are as follows.

1. Mechanical stability test This is a method based on the shell roll test of ASTM D 1831. It was operated at a temperature of 150 ° C for 72 hours, and the merit of mechanical stability was judged by the difference in the consistency of grease before and after the test.

2. Thermosetting test This is a method of measuring the immiscible consistency by leaving it at a predetermined temperature for 24 hours using a container for measuring the 1/2 scale of JIS K 2220 and then allowing it to cool to room temperature. The superiority or inferiority of the thermosetting property was judged by the percentage of the consistency difference between the front and rear grease.

3. Hydrous Shear Stability Test A. This is a method based on the ASTM D 1831 shell roll test, in which 10% water in grease is used as a sample, and it is operated at a temperature of 80 ° C for 24 hours. The superiority or inferiority of the water-containing shear stability was judged by the difference in the consistency of the grease before and after.

B. All judgments were made in the same way as in the previous section, except that grease containing 20% water was used as the sample.

4. Oil separation degree test method JIS K 2220 was used to determine the superiority or inferiority of the oil separation degree based on the percentage of the mass of oil separated after the test.

Further, the blending amounts of the respective raw materials of the urea grease used in each of the examples and comparative examples are as follows.

Mineral oil Viscosity 130 cSt (40 ° C) 90.99% by weight Viscosity index 105 Diphenylmethane-4,4'-diisocyanate 4.52% by weight Octylamine 3.82% by weight Aniline 0.67% by weight Example 1 37.715% by weight of the amount of mineral oil blended in the reactor A Preparation 80 ℃
Then, 3.64% by weight of the compounding amount of diphenylmethane-4,4'-diisocyanate was added to the reaction kettle A and stirred and mixed. Separately, 37.715% by weight of the blended amount of mineral oil is melted in pot A.
The octylamine was added to the melting pot A.
Was added to the reaction vessel A and stirred to cause a reaction.

At this time, the reaction product became about 9% by weight of the total amount. On the other hand, 7.78% by weight of the blended amount of mineral oil was charged into the reaction kettle B and heated to 80 ° C., and 0.88% by weight of the remaining amount of diphenylmethane-4,4'-diisocyanate was added to the reaction kettle B and mixed.

Separately, the remaining amount of mineral oil, 7.78% by weight, was charged into the melting pot B and heated to 80 ° C., and the entire amount of aniline was added to the melting pot B and stirred, and this was added to the reaction pot B and stirred to react. Also at this time, the amount of the reaction product was about 9% of the total amount. The temperature rose to 100 ° C due to the heat of co-reaction in the reaction kettles A and B. Set the temperature of each pot to 100
When the infrared absorption of each reaction composition was measured 30 minutes after the stirring was kept constant at 0 ° C., no absorption of isocyanate was observed. Therefore, all the reaction composition in the reaction vessel B was added to the reaction vessel A and mixed. Stirring was continued for 30 minutes at ° C.

After that, the temperature was raised to 190 ° C. by heating with stirring.
At this time, the temperature rising rate was set to 0.5 ° C. per minute to 190 ° C., the temperature was maintained at 190 ° C. for 60 minutes, then cooled and kneaded with a roll mill to obtain a sample.

Example 2 A sample was prepared in the same manner as in Example 1, except that the temperature rising rate was changed to 1.5 ° C./min.

Examples 3 to 5 The same method as in Example 1 was performed, and the mixing time was 30 minutes (Example 3), 20 minutes (Example 4), and 60 minutes (Example 5), and the temperature rising rate was 5.0 per minute. The sample was manufactured at a temperature of ℃.

Example 6 The same procedure as in Example 1 was carried out to terminate the reaction and to add the whole amount of the reaction composition in the reaction kettle B to the reaction kettle A, and after mixing, the mixture was cooled to 60 ° C., and stirring was continued at this temperature for 30 minutes. Subsequent operations were carried out in the same manner as in Example 1 except that the temperature rising rate was changed to 1.5 ° C./min to manufacture a sample.

Examples 7 to 9 and Comparative Examples 1 to 2 The reaction was completed in the same manner as in Example 1, the whole amount of the reaction composition in the reaction kettle B was added to the reaction kettle A, and the mixture was cooled to 80 ° C. (Example 7 ), Heated to 130 ° C. (Example 8), heated to 150 ° C. (Example 9), heated to 190 ° C. (Comparative Example 1), 25
The mixture was cooled to ℃ (Comparative Example 2), and stirring was continued at this temperature for 30 minutes.

Subsequent operations were carried out in the same manner as in Example 1, except that the temperature rising rate was 1.5 ° C./min and the samples were manufactured.

Comparative Example 3 Half the amount of mineral oil was charged into a reaction kettle and heated to 80 ° C., and the entire amount of diphenylmethane-4,4′-diisocyanate was added to the reaction kettle and mixed by stirring.

Separately, the remaining amount of mineral oil was charged into a dissolution tank, heated to 80 ° C., and the whole amount of octylamine and aniline was added to the dissolution tank and stirred, and dissolved, and this was added to a reaction tank and stirred to react. At this time, the heat of reaction increased the temperature to 100 ° C. The temperature was kept constant at 100 ° C. and stirring was continued. After 30 minutes, infrared absorption of the reaction composition was measured and no absorption of isocyanate was observed. Therefore, the temperature was raised to 190 ° C. while stirring. The rate of temperature rise at this time is set to 0.5 ℃ per minute, and it is increased to 190 ℃.
After maintaining the temperature at 190 ° C. for 60 minutes, it was cooled and kneaded with a roll mill to obtain a sample.

Comparative Example 4 A sample was prepared in the same manner as in Comparative Example 3, except that the temperature rising rate was changed to 5.0 ° C. per minute.

The properties of the grease, the mechanical stability test, the thermosetting test, the water-containing shear stability test, and the oil separation degree test were performed on these samples, respectively, and the effects were confirmed. Each of the greases of the examples has both mechanical stability and thermosetting property as compared with Comparative Examples 3 and 4 in which the grease of the prior application is used and also as compared with Comparative Examples 1 and 2 in which the mixing temperature is out of the range in the production method of the present invention. The water-containing shear stability was also excellent at the same level. In Examples 6 to 7 in which the mixing temperature was changed, the mechanical stability and the thermosetting property were excellent at about the same level, and Comparative Examples outside the mixing temperature range were used.
A clear difference was observed between 1 and 2. Comparative Example 1 mixed at 190 ° C. and Comparative Example 2 mixed at 25 ° C. resulted in poor mechanical stability and large oil separation. This is 190 ° C as described above
In the case of, a stable micelle structure was formed only with each urea compound, and the complex formation due to mixing was incomplete.In the case of 25 ° C, each urea compound was not dispersed and did not become complex. It is thought that it was because of it. Regarding the mechanical stability of Examples 3 to 5 in which the mixing time was changed, Example 3 was slightly superior to Example 3 in which the mixing time was 30 minutes, but all had high mechanical stability and thermosetting properties.

Next, the manufacturing method and effects of each example are shown in Tables 1 and 2 as a list.

[Effects of the Invention] As shown in Tables 1 and 2, after separately producing the urea compound having only the aromatic terminal group and the urea compound having only the aliphatic terminal group of the present invention in the base oil, The urea grease obtained by the production method characterized in that both reaction compositions are mixed at a specific temperature, and then the temperature is raised and the temperature is maintained at a high level is excellent in mechanical stability and has little thermosetting property. Shear stability was also excellent, and it was confirmed that the object of the present invention could be achieved.

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Claims (1)

[Claims] 1. A diisocyanate and an aromatic monoamine are added to a base oil and reacted at a temperature of 20 to 120 ° C., and a diisocyanate and an aliphatic monoamine are added to a base oil to be added to 20 to 12
After the reaction was maintained at a temperature of 0 ° C, both reaction compositions were heated to a temperature of 60
Twisted micelles, characterized in that they are mixed by keeping them at ~ 150 ° C, then reach a temperature of 170-200 ° C at a temperature rising rate of 0.3 ° C / min or more, and further hold in the temperature range for 0-180 minutes. A method for producing a urea grease having a fiber structure.