JPS63179998A - Production of lubricant containing urea compound - Google Patents

Abstract

PURPOSE:To obtain a lubricant in a labor-saving and economical way, outstanding in lubricating performance, by mechanically kneading at room temperature a specific urea compound and specified amount of lubricant oil or grease. CONSTITUTION:The objective lubricant can be obtained by kneading at room temperature (A) 1-30(pref., 3-25)wt.% of an urea compound of formula (U is urea; R1 is alkyl as a residue of isocyanate, aryl, etc.; R2 is alkyl as a residue of 6-20C monoamine, aryl, alicycle, etc.) and (B) a lubricant oil or grease using a kneader such as three-stage roller mill.

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention can be used in the same way as solid lubricants added to lubricating oils and greases used in lubricated parts of various mechanical parts. The present invention also relates to a method for producing a lubricant containing a urea compound, which can be used in the same way as other additives that improve lubricity, such as extreme pressure additives, oil agents, and friction modifiers.

(Prior art) Conventionally, urea grease was produced by
This method uses a urea compound, which is obtained by reacting the raw materials isocyanate and amine while heating, as a thickener. On the other hand, urea compounds have been widely used as grease thickeners, but in order to reduce the coefficient of friction, various lubrication additives are used.

(Problems to be Solved by the Invention) Conventionally, urea compounds have been extremely effective as thickeners for urea grease, and have been widely used in recent years.
This remains an unexamined issue. Therefore, in order to improve the lubricity of urea grease, various additives are currently being used in the same way as greases using metal soap as a thickener. However, these additives become extremely active at high temperatures, resulting in adverse effects such as destruction of the thickener. For example, ZIITP (zinc dithiophosphate), which is extremely effective as an extreme pressure additive, decomposes at 130°C, cutting the thickener micelles in grease and reducing its thickening ability. A phenomenon that seems to be occurring occurs. On the other hand, since urea grease has excellent oxidation stability and heat resistance, it is mostly used under high-temperature lubrication conditions. Under such conditions and when load resistance is required, solid lubricants such as molybdenum disulfide or organic molybdenum are currently added. However, these solid lubricants are expensive, and of course grease is also expensive, making it difficult to put them into practical use.

On the other hand, the amount of urea compounds synthesized during the production of urea grease is small compared to the base oil, and when producing grease using it as a thickener, urea compounds are synthesized in the base oil. After that, heating and temperature raising steps must be performed, which poses a problem in that large-scale equipment such as heating equipment is required.

(Means for solving the problem) As mentioned above, urea compounds are widely used as grease thickeners, but the lubrication mechanism of urea greases has a short history, so there are many unknowns. There are many fields. However, when observing lubricated parts used in various applications in which urea grease was used, many phenomena are observed that hint at the elucidation of the lubrication mechanism. For example, when we observe the transfer surfaces of bearings that have been using urea-based grease for a long period of time, we find that there is less wear, an oxide layer has formed, and urea compounds have formed compared to the transfer surfaces of bearings that have used conventional metallic soap grease. It appears to be attached to a metal surface. On the other hand, in the case of greases with thickeners such as lithium soap, the phenomenon seen with urea greases is hardly observed, and in most cases, abrasion progresses and the appearance of metallic luster occurs. In extreme cases,
In some cases, the condition is such that it can be detected by touch, that is, it is in a state of stepped wear. As a result of extensive research into the more effective use of urea compounds, which have these characteristics, not only as grease thickeners, but also as solid lubricants, we have found that specific urea compounds can be used in advance. It has been found that a lubricant obtained by first synthesizing the compound, adding it to a lubricating oil or urea grease, and mechanically kneading the compound has significantly improved lubricity.

That is, the method for producing a lubricant of the present invention is based on the following general formula % formula % (1) (in which U is a urea (-Nll-Co-N)l-) group,
R1 is an isocyanate residue, an alkyl group, an aryl group, or a derivative thereof; R2 has 6 to 20 carbon atoms;
an alkyl group, an aryl group, which is a residue of a monoamine,
A urea compound represented by (representing an alicyclic group or each derivative) is synthesized in advance, and this urea compound is
It is characterized in that 0 weight Mχ, preferably 3 to 25% by weight, and lubricating oil or grease are mixed using a kneading device at room temperature.

In the present invention, the mixing amount of the above urea compound is 1 to 3.
However, if the mixing amount is less than 1% by weight, the resulting mixture will be close to a liquid, and if this is used for various mechanical parts, it will leak due to defects in the sealing mechanism, etc., making it difficult to put it into practical use. do not.

In other words, the lubricant obtained by the production method of the present invention is
No matter how soft it is, it needs to be semi-fluid. On the other hand, if the amount of the mixture exceeds 30% by weight, the cost of the urea compound in the cost of the mixture increases significantly, and the resulting mixture naturally becomes expensive, which is also not practical.

According to the production method of the present invention, in addition to adding a pre-synthesized urea compound to lubricating oil and kneading it, a pre-synthesized urea compound is added to urea grease produced by a conventional method. The same effect can be obtained by adding and kneading.

The number of carbon atoms in the monoamine compound used is preferably 6 to 20. Monoamine compounds with less than 6 carbon atoms are difficult to handle during synthesis, and the polyaddition reaction does not proceed sufficiently, making it difficult to obtain a sufficient amount of urea compound. cannot be put to practical use.

Furthermore, amine compounds having a carbon number greater than 21 are difficult to obtain industrially at low cost, and are also not of practical use. On the other hand, the present applicant reported in JP-A No. 48-55902 that urea grease can also be obtained by dispersing a pre-synthesized urea compound in base oil, heating it, and then kneading it. and JP-A-49-132103, the urea compound synthesized in advance is subjected to heat treatment in the same manner as in the production of metal soap grease, and the lubrication of the grease obtained by these methods is improved. The lubricity is inferior to that of the lubricant obtained by the production method of the present invention.

This is because a pre-synthesized urea compound is dispersed in lubricating oil, heated, and kneaded.The thickener micelle structure formed by the urea compound changes, and the urea compound is produced in the base oil. This is thought to be due to the fact that the condition is the same as that of thickener micelles that are formed.

The kneading device used in the present invention can be a device used in the production of grease, such as a three-roll mill, a fryer mill, or a Montton-Gaulin mill.

However, when mixing and kneading a pre-synthesized urea compound with urea grease, using a Montton-Gorlin mill may cause the thickener micelles in the urea grease to be cut, resulting in a softening of the consistency. Negative effects such as oil separation may occur and caution is required. However, even when mixing with lubricating oil, if manual stirring is performed, the kneading effect is slow and the urea compound aggregates or forms into lumps, making uniform dispersion impossible. not reach the goal. In other words, mechanical kneading is essential as a method for dispersing pre-synthesized urea compounds in lubricating oils and greases. Therefore, by incorporating the above-mentioned kneading device in front of the lubricating part, it becomes possible for the user to mix the urea compound and lubricating oil, which was conventionally done by lubricant manufacturers. Furthermore, the mixing amount can also be varied according to each purpose and request, which can bring benefits such as integration of lubricants used up until now and labor savings.

The present invention provides a lubricant that can be obtained simply by mechanically mixing a pre-synthesized urea compound into a lubricating oil or grease, which is superior to the lubricating performance of urea grease obtained through the conventional urea grease manufacturing process. It was discovered that the lubricating performance of the agent is superior to that of the other agents. Furthermore, similar effects can be obtained even if the lubricant obtained by the present invention contains various lubricants such as antioxidants and rust preventives.

(Function) The urea compounds used in the present invention are shown in formula (1), and these urea compounds are preferable in the production of lubricants in view of the cost and availability of raw materials.

The urea compound is obtained by a polyaddition reaction between a diisocyanate and a monoamine in a polar solvent such as dimethylformamide. The isocyanate used here is commonly known as T,
Tolylene diisocyanate, called D,I, M,D
, diphenylmethane diisocyanate, called I
11. These include hexamethylene diisocyanate called D and I, and orthotoluidine diisocyanate called T, O, D and I, and R8 in the above formula (1) is a residue thereof. A monoamine is an amine compound in which an Nl2 group is bonded to R2 in formula (1), and R2
are residues of various monoamines.

The reason why the lubricant obtained by the production method of the present invention has such effects has not been confirmed, but it is generally thought as follows. A lubricant obtained by mixing a pre-synthesized urea compound and a lubricating oil is obtained by synthesizing the urea compound in a base oil through a polyaddition reaction of isocyanate and amine, then heating and kneading the mixture. It is difficult to imagine that the urea compound has the micellar structure (network structure) necessary for forming the grease structure, like the urea compound that acts as a thickener for urea grease. In other words, it is thought that the urea compound contained in the lubricant obtained by the production method of the present invention is simply a mixture of lubricating oil and fine urea compound, and the urea compound is used as a thickener for grease. It is thought that the affinity with lubricating oil is poorer than when it is. Therefore, when the lubricant obtained by the manufacturing method of the present invention is evaluated on the lubricated parts of various machines or on various lubricity evaluation test machines, the urea compounds present near the lubricated parts are more than normal urea grease. Also, it easily separates from lubricating oil. It is thought that the released urea compound actively adheres to the metal surface due to the adsorption effect of the metal surface and the action of the lone electron pair of the nitrogen atom, preventing direct contact between the metals. On the other hand, with regard to wear resistance, urea compounds are thought to have the effect of actively promoting the formation of an oxide layer on metal surfaces in such lubricated parts. The mechanism of this oxide layer formation is considered as follows. Compared to metal soaps such as lithium soap, urea compounds are more stable against oxidative deterioration due to their molecular structure, and
Unlike metal soaps, it does not contain metals that act as catalysts for promoting oxidative deterioration. In other words, during use in the actual lubricating part,
Metal soap decomposes into metals and organic acids mainly due to oxidation by atmospheric oxygen and accelerated oxidation by high temperature conditions.
The generated organic acid reacts with the metal surface to generate metal soap (for example, iron soap in the case of steel), and the generated metal soap undergoes oxidative deterioration and decomposes again. This is a chain reaction. This is a process in which the wear of the metal surface progresses as the metal surface is repeatedly worn. On the other hand, urea compounds are unlikely to undergo the same oxidation and decomposition process as metal soaps, and the mechanism is that excess oxygen near lubricated parts reacts with the metal surface to form a surface oxide film. . Furthermore, urea compounds are thought to have a stronger effect of dissolving atmospheric air (oxygen) in lubricants containing urea compounds than metal soaps.

In other words, about 80% of the atmosphere is composed of nitrogen, and some kind of interaction occurs with the nitrogen atoms contained in the urea group, resulting in air being contained in greases and lubricants containing urea compounds. The idea is that it will be easier. Therefore, it is thought that when the lubricant containing the atmosphere enters the lubricating part, it reacts with the metal surface and forms an oxide film due to the high temperature of the lubricating part due to microscopic high surface pressure conditions. However, urea compounds are thought to exhibit phenomena different from those of metal soaps due to their unique characteristics of adsorption to metal surfaces and the action of lone pairs of electrons in nitrogen atoms. As a result, it is expected that the urea compound attached to the metal surface will have a similar effect, and oxygen will be actively guided to the attached metal surface, and as a result,
The mechanism is to form an oxide film on the metal surface.

Regarding the lubricity of the oxide layer formed on the metal surface, it is said that the formation of iron oxides such as Fe30a (magnetite) in the lubricated area between the steels reduces the friction coefficient of the lubricated area. It is said.

It is believed that the lubricant obtained according to the present invention has the ability to promote the formation of these metal surface oxides.

The various phenomena of urea compounds, such as the adhesion of urea compounds to metal surfaces and the formation of oxidized layers, as described above, are similar to those often observed in bearings where urea grease has been used in various equipment. It is possible that the lubricant obtained by the present invention has this phenomenon (effect) more activated, and as a means of confirmation, FT4R
(Fourier Transform Infrastructure
red 5pectroscopy), AES
(8ugerElectron 5pectrosco
py), ESCA (Electron 5pectr-
Oscopy for Chemical Analysis
sis) etc. Such a phenomenon is not found in conventional greases using metal soap as a thickener, but in the lubricant obtained by the present invention, surface analysis was performed on the test piece subjected to the Bowden test in Example 1. As a result, the formation of an oxide film was confirmed.

(Effects of the Invention) The lubricant obtained by the production method of the present invention has the following advantages:
It was confirmed that the object of the present invention was achieved by exhibiting good lubricity.

(Examples and Comparative Examples) Examples and comparative examples are shown below, and the properties and results in the table will be briefly explained.

Regarding consistency, JIS K 22205.3
Measured based on. Further, in Examples and Comparative Examples, the state of dispersion of the urea compound in the obtained lubricants was observed using an optical microscope (100x magnification). Furthermore, using a Bauden-Siepen friction tester, the load was 3.0 kg, the sliding speed was 15 cm/sec, the material of the plate was 5 pcc, and the material of the ball was 5 U.
The test was conducted under the conditions of J-2 and test time of 10 minutes, and the dynamic friction coefficient μ and surface roughness (referred to as Ra) were measured using a roughness meter.

Step 1 Side 1- In a reactor, 540 g of N,N-dimethylformaldehyde (hereinafter referred to as DMF) and hexylamine (C6
Add 26.82g of HI3NHz), stir and heat.
The temperature was 0-80°C. Next, 33.18 g of tolylene diisocyanate (hereinafter referred to as TDT) was gradually added and reacted. After 30 to 60 minutes had passed from the start of the reaction, stirring and heating were stopped and the mixture was allowed to cool. 3000m of water when it cools down to room temperature
The mixture was placed in RO, uniformly dispersed using a glass rod, and filtered under reduced pressure using a suction bottle to remove DMF and water. Next, the filtered residue was poured into a stainless steel vat and left in an oven at 80°C for 72 hours to dry thoroughly. After drying, the synthesized white powder was ground with an agate mortar to obtain a white powder of 100 μW or less. In this way, 50g of the synthesized white powder was mixed with polyalphaolefin oil (40°C1
About 20 cS t) After uniformly mixing in 200 g, the sample was kneaded by passing it through a three-roll machine three times.

Flame 1 White powder 50 synthesized in the same manner as in Example 1 using dodecylamine instead of hexylamine in Example 1.
g, polyalphaolefin oil (40'C2 approx. 20
cS t) After uniformly mixing in 200 g, the mixture was kneaded using a three-roll machine to prepare a sample. The synthesis formulation is shown below.

DMF 540g Dodecylamine 40.8g TDI 19.2g White powder 5 synthesized in the same manner as in Example 1, using eicosylamine instead of hexylamine in Example 1.
0g of polyalphaolefin oil (40'C1 approx.
After uniformly mixing in 200 g of 0 cS t), the mixture was kneaded using a three-roll machine to prepare a sample. The synthesis formulation is shown below.

DMF 540g Eicosylamine 46.44g TDI 13.56g Jishin LiLL 50g of white powder synthesized in the same manner as in Example 1 using aniline instead of hexylamine in Example 1,
Polyalphaolefin oil (40°C1 approx. 20cS
t) After uniformly mixing in 200 g, the mixture was kneaded using a three-roll machine to prepare a sample. The synthesis formulation is shown below.

D MF 540g Aniline 3102g T D 1 28.98g Example 7. White powder synthesized in the same manner as in Example 1 except that p-toluidine was used in place of hexylamine in Example 1.
5g of polyalphaolefin oil (40°C1 approx.
After uniformly mixing in 242.5 g of 0cSt), the mixture was kneaded using a three-roll machine to prepare a sample. The synthesis formulation is shown below.

DMF 540g p-Toluidine 33.12g T D 1 26.88g 50g of white powder synthesized in the same manner as in Example 5 was mixed with polyalphaolefin oil (40°C2 about 20cSt)
After uniformly mixing in 200 g, the mixture was kneaded using a three-roll machine to prepare a sample.

, polyalphaolefin oil (40°C1 approx. 20c
After uniformly mixing in 187.5 g of S t), the mixture was kneaded using a three-roll machine to prepare a sample.

50 g of a white powder synthesized in the same manner as in Example 2 except that diphenylmethane diisocyanate (hereinafter referred to as MDI) was used in place of TDI in Example 2 was mixed with polyalphaolefin oil (approximately 20 cSt at 40°C). ) 20
After uniformly mixing the mixture into 0 g, it was kneaded using a three-roll machine to prepare a sample. The synthesis formulation is shown below.

DMF 540g Dodecylamine 35.82g MDI 24.18g Summation 50g of white powder synthesized in the same manner as in Example 4 using MDI instead of TDI in Example 4 was mixed with polyalphaolefin oil (40g). °C1 approx. 20cSt) 200g
After uniformly mixing the mixture, a sample was prepared using a three-roll machine.

The synthesis formulation is shown below.

D MF 540g aniline
25.62g M DI 34.38g Actual 11 Juice Rule To 180g of the grease of Comparative Example 3, which was made into a grease using TDI and dodecylamine as a thickener, 20g of the synthesized product of Example 2, which synthesized TDI and dodecylamine, was added.
After uniformly mixing, the mixture was kneaded using a three-roll machine and used as a sample.

Implementation ■u 50g of white powder synthesized in the same manner as in Example 2 was added to polyalphaolefin oil (40'C1 about 20cSt) 2
After uniformly mixing the mixture in 00g, the mixture was kneaded in a fryer mill to prepare a sample.

In the same manner as in Comparative Flame Example 5, 1.25 g of the synthesized white powder was heated in polyalphaolefin oil (40°C, about 20 cS
t) 248 was uniformly mixed in 75 g, and then kneaded with a three-roll machine to prepare a sample.

Kitakinen I 80 g of white powder synthesized from Nishi in the same manner as in Example 5 was mixed with polyalphaolefin oil (40°C, about 20 cSt) 1
After uniformly mixing in 70 g, the mixture was kneaded using a three-roll machine to prepare a sample.

Weigh out 400g of polyalphaolefin oil and 136g of dodecylamine into a stainless steel mug, and add 44g of polyalphaolefin oil to a stainless steel mug.
00 g and 70,164 g were weighed and stirred and heated to 70-80°C. Next, B was added to 8 and reacted for 30 minutes with stirring. Next, the temperature was raised to 180°C while stirring for about 2 hours, then held at 180±5°C for about 1 hour, then allowed to cool to room temperature, and then kneaded with a three-roll machine. It was used as a sample.

A sample was prepared by preparing a grease in the same manner as in Comparative Example 3 except that p-toluidine was used instead of dodecylamine in Comparative Example 3. The formulation is shown below.

p-) Luizine 110.4gTDI
89.6 g polyalphaolefin oil 800 g This 1 d I Using MDI in place of TDI in Comparative Example 3, Comparative Example 3
The sample was made into grease in the same manner as above. The formulation is shown below.

Dodecylamine 119.4gMDI
80.6 g polyalphaolefin oil 800 g Comparative example 3 Using MDI instead of TDIO in Comparative example 4
The sample was made into grease in the same manner as above. The formulation is shown below.

1)-) Luizine 107.8gMDI
92.2g polyalphaolefin oil 800g Beikianen 1 In the same manner as in Example 2, 50g of the synthesized white powder was uniformly mixed in 200g of polyalphaolefin oil, and then kneaded with a glass rod to prepare a sample.

Comparative Example 1 50 g of white powder synthesized in the same manner as in Example 6 and 200 g of polyalphaolefin oil were weighed in a stainless steel cake, and heated at 180° while stirring for about 2 hours.
The mixture was heated to 180±5°C for about 1 hour, then allowed to cool to room temperature, and kneaded using a three-roll machine to prepare a sample.

A sample was prepared by uniformly mixing 50 g of lithium stearate, commercially available from Kokki Iko, into 200 g of polyalphaolefin oil, and then kneading it with a three-roll machine.

The structural formulas of the urea compounds in the samples obtained in Examples 1 to 11 and Comparative Examples 1 to 9 are shown below, and the properties and test results are summarized in the table below.

Proceedings of the 1980s, Amendment of Procedures, March 3, 1988, Commissioner of the Japan Patent Office, Black 1) Akira A.1, Indication of the case, Patent Application No. 11365, filed in 1988, 2, Title of the invention: Lubricant containing urea compound Manufacturing method 3, Relationship with the case of the person making the amendment Patent applicant Kyodo Yushi Co., Ltd. 4, Agent 5, Subject of amendment Column 1 of "Detailed description of the invention" of the specification
, page 3, line 16 of the specification, ``At present, agents are added.'' [In some cases, agents are added to cope with the problem.'' ”
Correct to.

2. Delete page 3, line 19 to page 4, line 5.

3. Lines 13 to 15 of page 6, "The mixture also becomes expensive, which is also not practical." was changed to "The mixture also becomes expensive. Furthermore, the amount of lubricating oil to be kneaded is insufficient." Because of this, it is not always possible to obtain good lubrication performance.
This is also not practical. ”.

4. On page 12, line 8, "wear" is corrected to "abrasion."

5. In the 14th page, line 12, "in Example 1" is corrected to "as shown in the example."

6. In the summary of the manufacturing method of Comparative Example 7 in the table on page 27 of the same page, "Adding a urea compound to a lubricating oil and kneading with a glass rod" was changed to "Adding a urea compound to a lubricating oil and kneading with a glass rod." hand,
Knead the glass. ”.

Procedural amendment Written by the Commissioner of the Patent Office, March 30, 1988 Black 1) Mr. Akio 1, Indication of the case 1988 Patent Application No. 11365 2, Name of the invention Method for producing lubricant containing urea compound 3 , Relationship with the case of the person making the amendment Patent applicant Kyodo Yushi Co., Ltd. 4, Agent 5, Subject of amendment 1, Procedural amendment submitted on March 3, 1988, Page 2, No. 1
Line 7 [Knead the glass. ” [Knead with a glass rod.

”.

Claims (1)

[Claims] 1. The following general formula R_2-U-R_1-U-R_2 (1) synthesized in advance (in the formula, U is a urea (-NH-CO-NH-) group, R_1 is Represented by an alkyl group, an aryl group or a derivative thereof, which is a residue of an isocyanate; R_2 represents an alkyl group, an aryl group, an alicyclic group, or a derivative thereof, which is a residue of a monoamine having 6 to 20 carbon atoms. A method for producing a lubricant containing a urea compound, which comprises mixing 1 to 30% by weight of a urea compound and a lubricating oil or grease at room temperature using a kneading device.