JPH08295895A - Grease composition - Google Patents

Abstract

PURPOSE: To obtain a grease composition which is prepared by formulating prescribed amounts of a specific gelling agent and diphenyl hydrogen phosphite to a mineral base oil for lubricant and is useful for sliding parts because of its excellent fretting resistance. CONSTITUTION: This grease composition is given by formulating, as essential components, (A) 2-25wt.% of gelling agent composed of one or more selected from among ureas such as diurea of the formula (R<1> is a divalent 6-15C aromatic hydrocarbon; R<2> , R<3> are each cyclohexyl, a 7-12C cyclohexyl derivative, a 8-20C alkyl), urea-urethanes and urethanes and (B) 0.2-5.0wt.% of diphenyl hydrogen phosphite to (C) a synthetic lubricant base oil of mineral oil and/or n-paraffin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grease composition, and more specifically, to fretting wear generated in sliding parts, joints, etc. of parts intended to restrain relative motion or parts subjected to minute reciprocating motion ( The present invention relates to a grease composition for preventing fine movement wear).

[0002]

2. Description of the Related Art Shaft fit portions, bolt joints, rivet joints, taper joints, etc. for the purpose of restraining relative movement, or rolling bearings, slide bearings, ball bushes, spline shafts, flexible shaft joints, universal joints. In general, various mechanical parts such as leaf springs, coil springs, electric contacts, valves and valve seats, wire ropes, etc., which are accompanied by minute reciprocating motions, experience a phenomenon of wear called fretting. In particular, in automobiles, long-distance transportation by trailers or freight trains is performed, but fretting occurs on the bearing transfer surface due to micro-vibration during transportation, which is a problem.

Various methods have been proposed to prevent this fretting, one of which is a method of preventing fretting by selecting an appropriate lubricant. Among them, various reports on fretting prevention by grease lubrication have been made, but for example, for thickeners, there are cases where contradictory findings are obtained by the test method,
Further, regarding the additive, it is said that the one containing a phosphate is tentatively good, but the effect greatly differs depending on the structure. For this reason, it is the current situation that the fretting characteristics of grease have not been fully clarified.

On the other hand, the inventors of the present invention found a urea-based grease excellent in various properties and filed an application for it (Japanese Patent Publication No. 55-11156, Japanese Patent Publication No. 62-250097, and Japanese Patent Publication No. 64-9296). issue).

As a result of repeated studies, the inventors of the present invention have found that a grease containing a urea gelling agent and a specific compound is significantly higher in anti-fretting property than conventionally known greases. The present invention has been completed and the present invention has been completed.

[0006]

The present invention is excellent in the ability to prevent fretting wear that occurs in sliding parts and joints of parts for the purpose of restraining relative movement or parts that undergo minute reciprocating motion. It is an object to provide a grease composition.

[0007]

The present invention is a mineral oil system and / or
Or synthetic lubricant base oil, based on the total amount of the composition, (A)
2 to 25% by weight of a gelling agent comprising one compound or a mixture of two or more compounds selected from the group consisting of a urea compound, a urea-urethane compound, and a urethane compound, and (B) diphenyl hydrogen phosphite. 2 to
There is provided a grease composition characterized by being mixed with 5.0% by weight as an essential component.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The contents of the present invention will be described in more detail below. Mineral oil system used as the base oil of the present invention and /
Alternatively, as the synthetic lubricating oil, any oil that is usually used as a lubricating oil can be used. As the mineral oil-based lubricating oil, those which are appropriately combined and purified, such as vacuum distillation, solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, hydrodewaxing, sulfuric acid washing, clay refining, hydrorefining, etc., are used. , Specifically, for example, 70 pail oil, SAE1
0, SAE20, SAE30, SAE40, SAE5
There are various oils such as 0 and bright stock.

Specific examples of the synthetic lubricating oil include α-olefin oligomers such as normal paraffin, isoparaffin, polybutene, polyisobutylene and 1-decene oligomer; alkylbenzenes such as monoalkylbenzene, dialkylbenzene and polyalkylbenzene. Alkylnaphthalenes such as monoalkylnaphthalenes, dialkylnaphthalenes, polyalkylnaphthalenes; diesters such as di-2-ethylhexyl sebacate, dioctyl adipate, diisodecyl adipate, ditridecyl adipate, ditridecyl glutarate; trimethylolpropane caprylate, trimethylol Propane pelargonate, pentaerythritol-
2-Ethylhexanoate, pentaerythritol pelargonate, and other polyol esters; polyethylene glycol, polyethylene glycol monoether, polypropylene glycol, polypropylene glycol monoether, and other polyglycols; polyphenyl ether, tricresyl phosphate, silicone oil, perfluoro Examples thereof include alkyl ether. Further, two or more kinds of the above oils may be mixed and used. The preferred viscosity range of this mineral oil-based and / or synthetic lubricating base oil is
It is 10 to 200 cSt at 40 ° C.

As the component (A) of the present invention, one compound or a mixture of two or more compounds selected from the group consisting of a urea compound, a urea-urethane compound, and a urethane compound, a diurea compound, a triurea compound, What is known as a gelling agent of grease conventionally, such as a tetraurea compound, a polyurea compound, a urea-urethane compound, and a diurethane compound, may be used, but a particularly preferable one is the general formula (1).

[0011]

[Chemical 6]

(In the formula, R ¹ is a divalent aromatic hydrocarbon group having 6 to 15 carbon atoms, R ² and R ³ may be the same or different and each is a cyclohexyl group or 7 carbon atoms.
~ 12 cyclohexyl derivative group, or C8 ~
20 represents either an alkyl group or an alkenyl group of 20. Of at least one diurea compound having a cyclohexyl group or a derivative group thereof [{(number of cyclohexyl groups or derivative groups) / (number of cyclohexyl groups or derivative groups + alkyl group or alkenyl group) The number of groups)} × 100] is 20 to 90%, preferably 45 to 75%, and R ² is a cyclohexyl group or a derivative group thereof, and R ³ is an alkyl group or an alkenyl group. Mixture containing 10 mol% or more, general formula (2)

[0013]

[Chemical 7]

(In the formula, R ⁴ is a divalent aromatic hydrocarbon group having 6 to 15 carbon atoms, A and B may be the same or different, and R ⁵ —NH— (R ⁵ is A cyclohexyl group or a cyclohexyl derivative group having 7 to 12 carbon atoms, or an alkyl group or alkenyl group having 8 to 20 carbon atoms) or R ⁶ R ⁷ N-
(Wherein R ⁶ and R ^{7, which} may be the same or different, each represents a cyclohexyl group or a cyclohexyl derivative group having 7 to 12 carbon atoms) represents an amino group) At least 2
Consist of a mixture of higher species, and the amino group R ⁶ R ⁷ N-content of in the gellant [{amino group R ⁶ R ⁷ N-number / (amino group R ⁵ -NH- number + Number of amino groups R ⁶ R ⁷ N-)} ×
100] is 1 to 50%, preferably 5 to 40%,
Further, the ratio of the number of amino groups R ⁵ —NH— in which R ⁵ is a cyclohexyl group or a derivative group thereof to the number of amino groups R ⁵ —NH— in which R ⁵ is an alkyl group is 1/4 to 4/1. , Preferably a mixture of 3/7 to 7/3, and the general formula (3)
A diurea compound represented by 20 to 95 mol%, preferably 30 to 80 mol%,

[0015]

Embedded image

The urea-urethane compound represented by the general formula (4) is 4 to 30 mol%, preferably 10 to 30 mol%, and

[0017]

[Chemical 9]

Diurethane compound 1 represented by the general formula
˜50 mol%, preferably 10-40 mol%,

[0019]

[Chemical 10]

(In the formula, R ⁸ , R ¹¹ and R ¹⁴ may be the same or different, and a divalent aromatic hydrocarbon group having 6 to 15 carbon atoms is represented by R ⁹ , R ¹⁰ and R ^12; Cyclohexyl group or cyclohexyl derivative group having 7 to 12 carbon atoms, which may be the same or different, and R ¹³ , R ¹⁵ and R ^{16, which} may be same or different, are alkyl group or alkenyl group having 8 to 20 carbon atoms. Respectively have the composition of
And the amino groups R ⁹ NH-, R ¹⁰ NH- and R in the mixture
The total number of ¹² NH- and alkoxy groups R ¹³ O-, R ¹⁵ O
-, and R ¹⁶ Total number ratio of O- 95 / 5-40 / 6
The urea-urethane mixture is 0, preferably 85/15 to 60/40.

If the above mixture does not satisfy the above numerical values, it is disadvantageous in terms of performance such as thickening ability as a gelling agent.

In the above formulas (1) and (2), R ¹ , R ⁴ and R
⁸ , R ¹¹ and R ¹⁴ may be the same or different and each represents a divalent aromatic hydrocarbon group having 6 to 15 carbon atoms.
Specific examples of R ¹ , R ⁴ , R ⁸ , R ¹¹ and R ¹⁴ include aromatic hydrocarbon groups represented by the following structural formulas, but other ones are also divalent aromatics. If it is a hydrocarbon group, excellent performance such as thermal stability and oxidation stability is exhibited.

[0023]

[Chemical 11]

In the above formulas (1) and (2), R ² and R ³ may be the same or different and each is a cyclohexyl group or a cyclohexyl derivative group having 7 to 12 carbon atoms or 8 to 20 carbon atoms. An alkyl group or an alkenyl group is shown. R ⁵ is a cyclohexyl group, a cyclohexyl derivative group having 7 to 12 carbon atoms, or 8 carbon atoms.
~ 20 alkyl groups are shown. Also, R ⁶ , R ⁷ , R ⁹ , R ¹⁰
And R ¹² may be the same or different and each represents a cyclohexyl group or a cyclohexyl derivative group having 7 to 12 carbon atoms. Further, R ¹³ , R ¹⁵ and R ¹⁶ may be the same or different and each represents an alkyl group or an alkenyl group having 8 to 20 carbon atoms. Specific examples of the cyclohexyl group or the cyclohexyl derivative group having 7 to 12 carbon atoms include cyclohexyl group, methylcyclohexyl group, dimethylcyclohexyl group, ethylcyclohexyl group, diethylcyclohexyl group, propylcyclohexyl group, isopropylcyclohexyl group, 1- Methyl-
Examples thereof include a 3-propylcyclohexyl group, a butylcyclohexyl group, an amylcyclohexyl group, an amylmethylcyclohexyl group, and a hexylcyclohexyl group. Particularly preferred are a cyclohexyl group or a cyclohexyl derivative group having 7 to 8 carbon atoms, such as a methylcyclohexyl group and dimethyl. A cyclohexyl group and an ethylcyclohexyl group.

Specific examples of the alkyl group having 8 to 20 carbon atoms include octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group and heptadecyl group. , Octadecyl group, nonadecyl group, those having a linear structure or branched structure represented by eicosyl group and the like, and particularly preferred are alkyl groups having 16 to 19 carbon atoms, for example, hexadecyl group, heptadecyl group, octadecyl group. , A nonadecyl group.

Specific examples of the alkenyl group having 8 to 20 carbon atoms include octenyl group, nonenyl group,
A decenyl group, an undecenyl group, a dodecenyl group, a tridecenyl group, a tetradecenyl group, a pentadecenyl group, a hexadecenyl group, a heptadecenyl group, an octadecenyl group, a nonadecenyl group, those having a linear structure or a branched structure represented by an eicosenyl group, and the like, Particularly preferred are alkenyl groups having 16 to 19 carbon atoms, such as hexadecenyl group, heptadecenyl group, octadecenyl group and nonadecenyl group.

The method for producing the gelling agent which is the component (A) of the present invention is arbitrary, but in the case of a diurea compound, for example, by reacting an amine with diisocyanate,
In the case of a mixture of each compound of diurea, urea-urethane and diurethane, it can be produced in one step by reacting an amine and an alcohol with diisocyanate. At this time, volatile solvents such as benzene, toluene, xylene, hexane, naphtha, diisobutyl ether, carbon tetrachloride, petroleum ether and the like can be used. Further, a lubricating base oil can be used as a suitable solvent. The reaction temperature at this time is preferably 10 to 200 ° C.
In carrying out the reaction in this manner, sufficient mixing and stirring should be carried out so that a uniform grease is produced.

When a volatile solvent is used, the gelling agent produced in this manner is used as a grease by removing the solvent and adding an appropriate amount of a lubricating base oil. When a lubricating base oil is used as the solvent, it may be directly used as grease.

In the grease composition of the present invention, the content of the component (A) which is a gelling agent is 2 based on the total amount of the composition.
-25% by weight, preferably 3-20% by weight. (A)
If the content of the component does not reach the above range, there is no effect as a gelling agent, on the other hand, if the content of the component (A) exceeds the above range, it becomes too hard as a grease and exhibits sufficient lubricating performance. It is not preferable because it cannot be performed.

The component (B) of the present invention is diphenyl hydrogen phosphite represented by the following formula.

[0031]

[Chemical 12]

By incorporating diphenyl hydrogen phosphite, a grease having excellent fretting resistance can be obtained.

In the grease composition of the present invention, the content of the component (B) is 0.2 to 5.0% by weight, preferably 0.5 to 4.0% by weight, based on the total amount of the composition. If the content of the component (B) does not reach the above range, the effect is not sufficient. On the other hand, if the content of the component (B) exceeds the above range, various properties as a grease are adversely affected, which is not preferable.

The grease of the present invention can be added with an additive for further improving the performance without impairing its performance. Examples of the additive include metal soap, benton, other gelling agents such as silica gel, chlorine-based agents, sulfur-based agents, phosphorus-based agents, extreme pressure agents such as zinc dithiophosphate, and fatty agents such as fatty acids, animal oils and vegetable oils, Examples thereof include viscosity index improvers such as polymethacrylate, polybutene and polystyrene, amine-based, phenol-based, sulfur-based, antioxidants such as zinc dithiophosphate, and metal deactivators such as benzotriazole and thiadiazole.

[0035]

EXAMPLES The contents of the present invention will be described more specifically below with reference to examples and comparative examples. Synthesis Example 1 Diphenylmethane-4,4 'diisocyanate 8.08
6g in 174g of mineral oil (@ 40 ℃, 100cSt)
It was heated to 0 ° C. and uniformly dissolved. To this, 8.70 g of octadecylamine and 3.2 g of cyclohexylamine were mixed, heated and dissolved, and a vigorous stirring was carried out to form a gel-like substance immediately. 3 at 100 ° C with continuous stirring
After holding for 0 minutes, 6 g of the antioxidant was added, and the mixture was thoroughly stirred and then passed through a roll mill to obtain the target grease. The ratio of cyclohexyl group / octadecyl group of the produced diurea compound was 50/50. The gelling agent content is 10wt
%Met.

Synthesis Example 2 6.96 g of 2,4-2,6-tolylene diisocyanate
100 g of poly-α-olefin oil (@ 40 ° C, 44
cSt) and dissolved uniformly at room temperature. Add 1.97 g of cyclohexylamine and 11.10 of laurylamine.
When a mixture of g and g dissolved in the same poly-α-olefin oil was added and vigorously stirred, a gel-like substance was immediately produced. The mixture was kept for 30 minutes while continuing stirring, heated to raise the temperature to 80 ° C., and then passed through a roll mill to obtain the target grease. The produced diurea compound had a cyclohexyl group / dodecyl group ratio of 25/75 and a gelling agent content of 10 wt%.

Synthesis Example 3 11.96 g of vitrylene diisocyanate was added to 180 g of polyphenyl ether (@ 40 ° C., 67 cSt).
It was dissolved uniformly at 0 ° C. To this, 7.0 g of cyclohexylamine and 1.04 g of octylamine were mixed and homogenized, and when vigorously stirred, a gel-like substance was formed immediately. The temperature was raised to 120 ° C. while continuing stirring for 30 minutes, and the mixture was passed through a roll mill to obtain the target grease. The resulting diurea compound had a cyclohexyl group / octyl group ratio of 90/10 and a gelling agent content of 10 wt%.

Synthesis Example 4 Diphenylmethane-4,4'-diisocyanate 8.1
2 g was put into 120 g of mineral oil (@ 40 ° C., 100 cSt) and heated to 60 ° C. to dissolve it uniformly. To this, 6.11 g of octadecylamine, 2.25 g of cyclohexylamine and 3.52 g of dicyclohexylamine were added,
When g was dissolved in heat and added with vigorous stirring, a gel-like substance was immediately formed. After maintaining the temperature at 100 ° C. for 30 minutes while continuing stirring, the target grease was obtained by passing through a roll mill. The resulting diurea compound had an octadecylamino group / cyclohexylamino group / dicyclohexylamino group ratio of 35/35/30 and a gelling agent content of 10% by weight.

Synthesis example 5 2,4-2,6-tolylene diisocyanate 40.3 g
Was added to 100 g of mineral oil (@ 210 ° F, 10.5 cSt) and uniformly dissolved at room temperature. To this, 32.1 g of cyclohexylamine and 37.
A mixture of 6 g and 390 g of the same mineral oil dissolved therein was added, and when vigorously stirred, a gel-like substance was immediately produced. Hold the temperature for 30 minutes with continuous stirring, and heat to 10
After raising the temperature to 0 ° C., it was passed through a roll mill to obtain the target grease. The ratio of cyclohexylamino group / octadecyloxy group of the urea-urethane compound formed is 7
At 0/30, the content of gelling agent was 11% by weight.

Example 1 and Comparative Examples 1 to 6 The component (B) was blended with the base grease obtained in the above synthesis example to obtain a grease having the composition shown in Table 1 (Example 1).
For comparison, the above base grease was used (B)
Table 1 shows the compositions of greases containing no components (Comparative Examples 1 to 5) and commercial fretting-resistant urea grease (Comparative Example 6). The following evaluation tests were performed on these greases, and the results are also shown in Table 1. <Performance Evaluation Test> (Fretting Resistance Test) A performance evaluation test was conducted using a Faffner friction oxidation tester in accordance with ASTM G-III-12. As the bearing, 51204 was used, and the test time was 2 hours.

[0041]

[Table 1]

[0042]

As is clear from the results shown in Table 1, the composition of Example 1 according to the present invention has excellent fretting resistance. On the other hand, when the component (B) is not blended (Comparative Examples 1 to 5), the fretting resistance is significantly inferior to the composition of the present invention. Also, a grease that has been conventionally said to have excellent fretting resistance (Comparative Example 6)
Also has inferior fretting resistance compared to the composition of the present invention.

As described above, the grease composition of the present invention is
It is a grease composition having excellent fretting resistance as compared with conventionally known greases.

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Claims (4)

[Claims] 1. A mineral oil-based and / or synthetic lubricating base oil, and one compound or 2 selected from the group consisting of (A) a urea compound, a urea-urethane compound, and a urethane compound based on the total amount of the composition. A gelling agent comprising a mixture of two or more compounds, 2 to 25% by weight, and (B) diphenylhydrogen phosphite 0.2 to 5.0% by weight as essential components. Composition. 2. The gelling agent is represented by the general formula (1): (In the formula, R ¹ is a divalent aromatic hydrocarbon group having 6 to 15 carbon atoms, R ² and R ³ may be the same or different, and each is a cyclohexyl group or a cyclohexyl having 7 to 12 carbon atoms. A derivative group, or a diurea compound having at least one of an alkyl group or an alkenyl group having 8 to 20 carbon atoms) and having a content of a cyclohexyl group or its derivative group [{(cyclohexyl group or The number of derivative groups) / (the number of cyclohexyl groups or derivative groups + the number of alkyl groups or alkenyl groups)} × 100] is 20 to 90%, and R ² is a cyclohexyl group or a derivative group thereof, And 10 mol% of a compound in which R ³ is an alkyl group or an alkenyl group
The composition according to claim 1, comprising a mixture containing the above. 3. The gelling agent is represented by the general formula (2): (In the formula, R ⁴ is a divalent aromatic hydrocarbon group having 6 to 15 carbon atoms, A and B may be the same or different,
An amino group represented by R ⁵ —NH— (R ⁵ represents either a cyclohexyl group, a cyclohexyl group having 7 to 12 carbon atoms, or an alkyl group having 8 to 20 carbon atoms), or R ⁶ R ⁷ N- (R ⁶ and R ⁷ may be the same or different and each represents either a cyclohexyl group or a cyclohexyl derivative group having 7 to 12 carbon atoms). Consists of a mixture of at least two diurea compounds, and the content of amino group R ⁶ R ⁷ N- in the gelling agent.
[{Number of amino groups R ⁶ R ⁷ N-/ (number of amino groups R ⁵ -NH- + number of amino groups R ⁶ R ⁷ N-)} x 100] is 1 to 50
%, And the ratio of the number of amino groups R ⁵ —NH— in which R ⁵ is a cyclohexyl group or its derivative group to the number of amino groups R ⁵ —NH— in which R ⁵ is an alkyl group is 1/4. ~ 4 /
The composition of claim 1 which is 1. 4. The gelling agent, 20 to 95 mol% of a diurea compound represented by the general formula (3): Urea-urethane compound 4 represented by the general formula (4)
˜30 mol%, and Diurethane compounds 1 to 50 represented by the general formula (5)
Mol%, (In the formula, R ⁸ , R ¹¹ and R ¹⁴ may be the same or different and each represents a divalent aromatic hydrocarbon group having 6 to 15 carbon atoms;
⁹ , R ¹⁰ and R ¹² may be the same or different and may be a cyclohexyl group or a cyclohexyl derivative group having 7 to 12 carbon atoms, and R ¹³ , R ¹⁵ and R ¹⁶ may be the same or different and have 8 to 8 carbon atoms. 20 alkyl groups or alkenyl groups are shown respectively. It has the composition), and an amino group R ⁹ NH- in the mixture, R ¹⁰ NH-, and R ¹² the total number and the alkoxy group R ¹³ O-of NH-, R ¹⁵ O-and the sum of R ¹⁶ O- A composition according to claim 1 which comprises a urea-urethane mixture having a number ratio of 95/5 to 40/60.