JPS5811920B2 - Urea-based grease composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel urea-based grease composition, and more specifically, an aliphatic grease composition having two urea groups in one molecule and whose terminal ends are the base oil components of the lubricating grease. Concerning a urea-based grease composition characterized by long service life at high temperatures, consisting of hydrocarbons, alicyclic hydrocarbons, and aromatic hydrocarbons, in which the groups are in the same ratio as the components constituting the base oil. It is.

Some of the machines currently in widespread use operate at high speeds, high temperatures, and loads, and some have special lubrication requirements.

Various known all-purpose greases conventionally used in these machines are unsatisfactory because they cause poor lubrication and have a short lifespan.

One of the reasons for this is that the metal soaps used as thickeners in many known all-purpose greases act as oxidation catalysts on the base oil, thereby deteriorating the lubricating grease and significantly shortening its life.

This necessitates the use of various additives.

Synthetic resin-based thickeners, particularly urea-based compounds, are being used as thickeners that have recently attracted attention.

Lubricating grease enriched with urea compounds has heat resistance, water resistance, oxidation resistance, etc., and is therefore attracting attention as a high-temperature, long-life grease.

However, commercially available urea-based greases have problems with hardening phenomena and shear stability at high temperatures.

Therefore, it cannot be said that the grease has a sufficiently long life.

In addition, when naphthenic oils or some synthetic oils are used as base oils, there are disadvantages such as the need to use a large amount of thickener to make grease with a certain consistency, and poor heat resistance and shear stability. be.

An object of the present invention is to provide a stable, high-temperature, long-life grease that compensates for the drawbacks of known all-purpose greases and urea-based greases and can be enriched with many base oils.

Lubricating grease consists of a base oil and a thickener, and from a microscopic perspective, the molecules of the thickener are not simply dispersed in the base oil, but the molecules of the thickener interact with each other due to weak forces such as Coulomb force and van der Waals force. Large molecular aggregates are formed by the attraction force.

Normally, molecular aggregates are called micelles and form a non-Newtonian fluid that envelops the base oil in a sponge-like manner.

Also, the molecules on the surface of the micelles attract oil molecules due to van der Waals forces, etc., and work to prevent the oil from escaping from the mesh-like micelles.

Therefore, there is a close relationship between thickener molecules and base oil molecules, and not all substances that form micelles can be used as thickeners.

Furthermore, the molecules of the thickener must have intermolecular attraction and have a molecular structure that is compatible with oil molecules in order to form micelles.

In the present invention, since the end of the thickener molecule and the base oil molecule have the same shape, the connection, compatibility, and affinity between both molecules are improved, and the ability of the micelles to retain oil is high. You can now make hard grease.

This is economically very advantageous. In addition, there is no sudden oil separation from the grease at high temperatures, and the oil held in the micelles can be supplied little by little to the lubricated surface over a long period of time.

As described above, in the present invention, by satisfying the above conditions, it has become possible to significantly extend the service life of the grease at high temperatures.

Mineral oil, which is generally used as a base oil for lubricating grease, is structurally made up of a complex mixture of aliphatic hydrocarbons, alicyclic hydrocarbons, and aromatic hydrocarbons, but there are several methods for analyzing them. Ring analysis is currently widely used as a method of analysis, and the nd-N method of K. VAN NES et al. and the ri-VGC method proposed by KURTZ et al. of SUN oil CO. AST
It has been adopted as MD-2140.

In either method, a lot of data is collected and analyzed, such as the relationship between the physical constants of pure hydrocarbons and their structure, or the relationship between the physical constants of lubricating oil fractions before and after hydrogenation and their structure, and the analysis of the data results in the actual lubricating oil. The physical constants and structures of fractions are related using mathematical formulas or nomographs.

The numbers obtained from these analyzes are expressed as percentages of aliphatic hydrocarbons (paraffinic components), alicyclic hydrocarbons (naphthenic components), and aromatic hydrocarbons (aromatic components). It is something.

The urea-based grease composition of the present invention has the following formula: where R is a divalent hydrocarbon compound having 2 to 20 carbon atoms and a derivative thereof, and R' is a monovalent hydrocarbon compound having 1 to 20 carbon atoms and a derivative thereof. Furthermore, R' is a combination of several types of compounds in the same group as each component of the base oil analyzed by ring analysis in the same ratio as each component of the base oil.

Examples of groups that can be used include R tolylene, diphenylmethane, citrylene, and naphthalene; R' include octyl, dodecyl, hexadecyl, octadecyl, cyclohexyl, ethylcyclohexyl,
There are dicyclohexyl group, phenyl group, diphenyl group, ethylphenyl group, and ethoxyphenyl group.

Furthermore, other similar compounds can be used, but these exhibit the best properties.

The method for producing the urea compound of the present invention is shown in the following reaction formula. In the derivative, R' is a compound of the same family as the constituent components of the base oil used, and is combined in the same proportion as the base oil.

Although the above two formulas can be considered for synthesizing the urea compound of the present invention, formula (1) will be used for explanation.

When using a base oil whose structural analysis values are 70% aliphatic components, 20% alicyclic components, and 10% aromatic components, 2 moles of monoamine and 1 mole of diisocyanate are reacted. Make the following combinations of monoamines.

The proportions are 70% aliphatic monoamine, 20% alicyclic monoamine, and 10% aromatic monoamine.

Although the synthesized urea-based compound is not a single one, an ideal compound with a structure most similar to that of base oil and good compatibility can be obtained.

The reaction can also be carried out in a solvent or in a base oil in combination.

Examples of the solvent used include n-hexane, benzene, toluene, and xylene.

When the reaction is carried out in a solvent, diisocyanate dissolved in the solvent is placed in a reaction vessel, a solution containing dissolved amines is gradually added, the reaction is carried out, and the mixture is refluxed.

After completion of the reaction, the solvent is removed, and after drying, it is added to the base oil, uniformly dispersed, kneaded and adjusted to obtain a grease.

When reacting in base oil, as with the reaction in a solvent, each raw material is dissolved in the base oil and slowly added, and after the reaction is heated to raise the temperature to about 130 to 200 ° C to complete the reaction and kneaded. adjust.

The content of urea compounds in the lubricating grease of the present invention is 2
Approximately 40% or so is suitable, and outside this range it does not exhibit the properties of grease.

Furthermore, various additives may be added to further improve the performance of this lubricating grease.

Base oils used in the urea-based grease composition of the present invention include paraffinic mineral oils, naphthenic mineral oils, and other stratified hydrogen oils, and synthetic oils include alkylene polymers, alkylene oxide polymers, carboxylic acid esters, phosphoric acid esters, Alkylbenzenes, polyphenyl ethers, alkyl biphenyl ethers, silicone polymers, fluorine oils, and the like can be used alone or in combinations thereof.

In the case of mineral oils, the raw materials and raw material composition are determined by the ring analysis described above, but in the case of synthetic oils, the structure of each base oil is analyzed to determine the ratio of aliphatic components, alicyclic components, and aromatic components. The composition must be decided based on the results.

Next, the present invention will be explained in more detail with reference to examples.

Comparative examples are also listed to demonstrate the superiority of the urea-based grease of the present invention.

Example 1 Paraffinic mineral oil containing 70% aliphatic components, 20% alicyclic components, and 10% aromatic components (14% at 98.9°C
．． Add 33.6 g of 44'-diphenylmethane diisocyanate to 500 g of (viscosity: 4 cst) and heat to 50° C. to dissolve.

To this, 31.7 g of octadecylamine, 10.0 g of cyclohexylamine, and 4.7 g of aniline were added to the mineral oil 42 g.
While gradually adding a solution heated and dissolved to 0 g, stir vigorously.

When the grease becomes uniform, start heating to 150 ml.
The reaction is completed by heating and stirring to ℃.

After cooling to room temperature, knead and adjust.

Test results: immiscible consistency 252, miscible consistency 268, dropping point 2
It was a lubricating grease with properties of 61°C.

In addition, the immiscible consistency and the miscible consistency are JIS-2560,
The dropping point was measured according to JIS-2561.

Example 2 500 g of naphthenic mineral oil (having a viscosity of 8.6 cst at 989°C) containing 38.5% aliphatic components, 45% alicyclic components, and 165% aromatic components was mixed with vitriol. 42.2 g of diisocyanate is placed in a reaction vessel and heated to 80°C to dissolve.

Next, 22.8 g of dodecylamine, 26.1 g of P-bicyclohexylamine, and 8.9 g of P-biphenylamine are heated and dissolved in 400 g of naphthenic mineral oil, and the mixture is gradually added to the reaction vessel while stirring vigorously.

When the mixture becomes uniformly grease-like, heating is started and the reaction is completed by heating and stirring to 150°C.

After cooling to room temperature, knead and adjust.

The properties of the resulting grease were as follows. Immiscibility consistency 2
64, mixing consistency 279, dropping point 268°C.

Example 3 30% bisphenoxybiphenyl and polyα- as base oil
A mixed oil containing 70% olefin was used.

Add 66% of vitolylene diisocyanate to 500g of this mixed oil.
．． Dissolve 5g by heating to 80°C and put into a reaction vessel.

Next, 58.5 g of octadecylamine was added to 350 g of mixed oil.
Dissolve 26.0 g of aniline by heating to make a homogeneous solution, and gradually add it to the reaction vessel while stirring vigorously.

When the mixture becomes uniformly grease-like, heating is started and the reaction is completed by heating and stirring to 150°C.

After cooling to room temperature, knead and adjust.

The properties of the resulting grease were an immiscible consistency of 265, a miscible consistency of 273, and a dropping point of 280°C.

Example 4 Paraffinic mineral oil containing 90% aliphatic components, 5% alicyclic components, and 5% aromatic components (12.1% at 98.9°C)
cst viscosity) to 500g and 12.8g of octylamine.
Add and mix well.

Next, 400 g of the above mineral oil was placed in a reaction vessel and 40.4 g of tolylene diisocyanate was dissolved therein.

The above-mentioned mixture of amines is gradually added to this solution while stirring vigorously.

When it becomes a uniform grease-like state, it is heated to 150°C to complete the reaction.

After cooling to room temperature, knead and adjust.

The resulting grease had properties such as an immiscible consistency of 247, a miscible consistency of 262, and a dropping point of 282°C.

Example 5 46.9 g of naphthalene diisocyanate was dissolved in 300 ml of methyl ethyl ketone, and the aliphatic component was 70 ml.
%, paraffinic mineral oil with 20% alicyclic components and 10% aromatic components (viscosity 8
Mix with 80g.

Next, 41.9 g of hexadecylamine, 16.7 g of cyclohexylamine, and 14.5 g of ethoxyphenylamine.
was dissolved in 300 g of methyl ethyl ketone and gradually added to the above solution.

When it became a homogeneous grease, it was heated to distill off the methyl ethyl ketone and the temperature was raised to 180°C to complete the reaction.The whole was allowed to cool and then kneaded and adjusted to obtain a grease containing 12% of urea compound.

Next, a comparative grease was manufactured using the same base oil as in the example.

As comparative examples, commercially available urea-based greases represented by patent publications Sho 39-3114, Sho 45-22407, and Sho 47-4210 were used, and greases were produced as follows according to examples of these production methods. .

Comparative example 1 44'-diphenylmethane diisocyanate 141.5
A mixture of g and 350 ml of methyl ethyl ketone is heated to 65°C.

Paraffinic mineral oil 108 used in Example 1 was added to this mixture.
Add 9 g of methylene dianiline to this mixture and add 56 g of methylene dianiline.
A solution of 1 g and 152.2 g of octadecylamine dissolved in 350 ml of warm methyl ethyl ketone is added with stirring.

This is heated to 150°C, further raised to 200°C, and 752g of the above-mentioned paraffinic mineral oil is added.

After the whole was cooled, it was kneaded and adjusted to obtain a lubricating grease containing 19% of a urea compound.

In Comparative Example 2, the naphthenic mineral oil used in Example 2 was used instead of the paraffinic mineral oil used as the base oil in Comparative Example 1.

Comparative Example 3 used the same mixture of bisphenoxybiphenyl and polyα-olefin used in Example 3.

The above examples and comparative examples are summarized in Table 1 and shown on the next page.

To explain Table 1, Example 1 and Comparative Example 1 are lubricating greases thickened with the same paraffinic mineral oil, but Comparative Example 1 has a higher thickening agent content and has poor shear stability and high temperature curing phenomenon. It's bad.

Next, in Example 2 and Comparative Example 2, although the thickener content in the Comparative Example is lower, the dropping point for evaluating heat resistance is significantly lower, and curing at high temperatures is greater.

Comparing Example 3 and Comparative Example 3, Comparative Example 3 has a soft consistency and a low dropping point despite having the same thickener content.

Other properties are not worth evaluating. Looking at the lifespan of Federal, overall, Examples have better shear stability and curing at high temperatures, and have a much longer lifespan.

In addition, although Examples 4 and 5 were made with paraffin mineral oil, various base oils with different ring analysis ratios and different viscosities can be thickened by using the urea compound of the present invention. We were able to make high quality grease.

As described above, although the urea-based grease of the comparative example can be made into a grease depending on the type of base oil, its properties are significantly deteriorated.

As mentioned above, since the urea-based grease of the present invention uses raw materials having groups similar to those of the base oil used, any base oil used in the grease can be made into a grease with a small amount of thickener. It is very economical.

In terms of properties, heat resistance and shear stability are improved, and the curing phenomenon at high temperatures, which was a drawback of urea-based greases, can be greatly improved.

Furthermore, in the relationship between the base oil and the thickener involved in the composition of lubricating grease, a feature of the present invention is that if a chemical reaction is carried out to obtain a thickening effect using either of them as a main ingredient according to the method of the present invention, high temperature, It is possible to provide an extremely useful urea-based grease composition that is endowed with the characteristics of a long-life lubricating grease.

Claims (1)

[Claims] 1. In a urea-based grease composition containing 2 to 40% of a grease thickener using mineral oil or synthetic oil as a base oil, R is any one of a tolylene group, a diphenylmethane group, a citrylene group, or a naphthalene group; ' is an alkyl group, a cycloalkyl group, an aryl group, or a combination thereof, where the alkyl group is an octyl group, a dodecyl group, a hexadecyl group, or an octadecyl group, and the cycloalkyl group is a cyclohexyl group, an ethylcyclohexyl group, or a dicyclohexyl group. The aryl group is a phenyl group, diphenyl group, ethylphenyl group, or ethoxyphenyl group, and the ratio of alkyl groups, cycloalkyl groups, and aryl groups is a paraffinic component that was analyzed by ring analysis of the components that make up the base oil of grease. , a naphthenic component, and an aromatic component in proportions corresponding to each other.