JP2732245B2 - Grease composition - Google Patents

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 particularly, to fretting wear (e.g., fretting wear) generated on a sliding portion, a joint portion, etc. of a component for restraining relative motion or a component subjected to minute reciprocating motion. Grease composition for preventing fine movement abrasion).

[0002]

2. Description of the Related Art Shaft fittings, bolted joints, rivet joints, tapered joints, etc. for restraining relative motion, 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 have minute reciprocating movements, suffer from a wear phenomenon called fine movement wear (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 the fretting. One of the methods is to select an appropriate lubricant to prevent the fretting. Among them, various reports on fretting prevention by grease lubrication have been made, but for example, for thickeners, conflicting findings may be obtained by test methods,
As for the additives, those containing a phosphate salt are considered to be good, but the effect differs greatly depending on the structure. For this reason, at present, the fretting characteristics of grease have not been sufficiently elucidated.

On the other hand, the present inventors have found urea-based greases excellent in various performances and have already filed applications (JP-B-55-11156, JP-A-62-250097, JP-A-64-9296). issue).

As a result of repeated studies, the present inventors have found that grease containing a urea-based gelling agent and a specific compound added thereto has a remarkably high antifretting property as compared with conventionally known grease. And completed the present invention.

[0006]

DISCLOSURE OF THE INVENTION The present invention has an excellent performance for preventing fretting wear generated on sliding parts and joints of parts intended to restrain relative movement and parts subjected to minute reciprocating movement. It is intended to provide a grease composition.

[0007]

SUMMARY OF THE INVENTION The present invention provides a mineral oil based and / or
Or, in a synthetic lubricating base oil, (A)
2 to 25% by weight of a gelling agent comprising one compound selected from the group consisting of a urea compound, a urea / urethane compound, and a urethane compound or a mixture of two or more compounds; and (B) 0.1% of diphenyl hydrogen phosphite. Two
Provided is a grease composition characterized by comprising 5.0% by weight as an essential component.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the contents of the present invention will be described in more detail. Mineral oil used as the base oil of the present invention and / or
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 obtained by appropriately combining and purifying under reduced pressure, solvent dewaxing, solvent extraction, hydrocracking, solvent dewaxing, hydrodewaxing, sulfuric acid washing, clay refining, hydrorefining, etc. are used. Specifically, for example, 70 pale oil, SAE1
0, SAE20, SAE30, SAE40, SAE5
Various oils such as 0, bright stock and the like.

Specific examples of synthetic lubricating oils include α-olefin oligomers such as normal paraffin, isoparaffin, polybutene, polyisobutylene, and 1-decene oligomer; and alkylbenzenes such as monoalkylbenzene, dialkylbenzene, and polyalkylbenzene. Alkylnaphthalenes such as monoalkylnaphthalene, dialkylnaphthalene, and polyalkylnaphthalene; diesters such as di-2-ethylhexylsebacate, dioctyladipate, diisodecyladipate, ditridecyladipate, and ditridecylglutarate; trimethylolpropanecaprylate and trimethylol Propaneperargonate, pentaerythritol-
Polyol esters such as 2-ethylhexanoate and pentaerythritol pelargonate; polyglycols such as polyethylene glycol, polyethylene glycol monoether, polypropylene glycol and polypropylene glycol monoether; polyphenyl ether, tricresyl phosphate, silicone oil, perfluoro Alkyl ether and the like. Further, two or more kinds of the above oils may be used as a mixture. The preferred viscosity range of the mineral and / or synthetic lubricating base oil is
It is 10 to 200 cSt at 40 ° C.

The compound (A) of the present invention includes a urea compound, a urea / urethane compound, and one compound selected from the group consisting of urethane compounds, or a mixture of two or more compounds, such as a diurea compound, a triurea compound, Any of the compounds conventionally known as a grease gelling agent, such as a tetraurea compound, a polyurea compound, a urea / urethane compound, and a diurethane compound, may be used. Particularly preferred is a compound represented by the general formula (1)

[0011]

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(Wherein R ¹ is a divalent aromatic hydrocarbon group having 6 to 15 carbon atoms, and R ² and R ³ may be the same or different and each is a cyclohexyl group or a C 7
To 12 cyclohexyl derivative groups, or 8 to 8 carbon atoms
20 represents either an alkyl group or an alkenyl group. ), And the content of cyclohexyl group or its derivative group [{(number of cyclohexyl group or its derivative group) / (number of cyclohexyl group or its derivative group + alkyl group or alkenyl) The number of groups) {x100] is 20 to 90%, preferably 45 to 75%, and R ² is a cyclohexyl group or a derivative thereof, and R ³ is an alkyl group or an alkenyl group. A mixture containing 10 mol% or more, general formula (2)

[0013]

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(Wherein R ⁴ is a divalent aromatic hydrocarbon group having 6 to 15 carbon atoms, A and B may be the same or different, and each of R ⁵ -NH- (R ⁵ is An amino group represented by 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 may be the same or different and each represents either a cyclohexyl group or a cyclohexyl derivative group having 7 to 12 carbon atoms). 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%,
The ratio of the number of amino groups R ⁵ —NH— in which R ⁵ is a cyclohexyl group or a derivative thereof to the number of amino groups R ⁵ —NH— in which R ⁵ is an alkyl group is １ ／ to 4/1. And preferably a mixture of 3/7 to 7/3, and a compound represented by the general formula (3):
20 to 95 mol%, preferably 30 to 80 mol%, of a diurea compound represented by

[0015]

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4 to 30 mol%, preferably 10 to 30 mol% of a urea / urethane compound represented by the general formula (4), and

[0017]

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

[0019]

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(Wherein 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⁾ A cyclohexyl group or a cyclohexyl derivative group having 7 to 12 carbon atoms, which may be the same or different, and an alkyl group or an alkenyl group having 8 to 20 carbon atoms, wherein R ¹³ , R ¹⁵ and R ¹⁶ may be the same or different. Are respectively shown.)
And the amino groups R ⁹ NH—, R ¹⁰ NH— and R
¹² NH— and the alkoxy groups R ¹³ O— and R ¹⁵ O
-, and R ¹⁶ Total number ratio of O- 95 / 5-40 / 6
0, preferably a urea / urethane mixture having a ratio of 85/15 to 60/40.

If the above-mentioned numerical values are not satisfied in the above-mentioned mixture, 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 , 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, for example, aromatic hydrocarbon groups represented by the following structural formulas. If it is a hydrocarbon group, excellent performance such as thermal stability and oxidation stability will be exhibited.

[0023]

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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 a cyclohexyl derivative group having 8 to 20 carbon atoms. It represents an alkyl group or an alkenyl group. R ⁵ is a cyclohexyl group or a cyclohexyl derivative group having 7 to 12 carbon atoms, or
And represents an alkyl group of -20. 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. 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 a cyclohexyl group, a methylcyclohexyl group, a dimethylcyclohexyl group, an ethylcyclohexyl group, a diethylcyclohexyl group, a propylcyclohexyl group, an isopropylcyclohexyl group, and 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 and a cyclohexyl derivative group having 7 to 8 carbon atoms, such as a methylcyclohexyl group and dimethyl. A cyclohexyl group and an ethylcyclohexyl group.

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

The alkenyl group having 8 to 20 carbon atoms specifically includes, for example, an octenyl group, a nonenyl group,
Decenyl group, undecenyl group, dodecenyl group, tridecenyl group, tetradecenyl group, pentadecenyl group, hexadecenyl group, heptadecenyl group, octadecenyl group, nonadecenyl group, those having a linear structure or a branched structure represented by eicosenyl group, and the like. Particularly preferred are alkenyl groups having 16 to 19 carbon atoms, for example, 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 optional. For example, in the case of a diurea compound, an amine is reacted with a diisocyanate.
In the case of a mixture of each compound of diurea, urea / urethane, and diurethane, each can be produced in one step by reacting an amine and an alcohol with a 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 from 10 to 200 ° C.
In reacting in this manner, it is necessary to mix and stir well so that uniform grease is produced.

When a volatile solvent is used in the gelling agent thus produced, the solvent is removed and an appropriate amount of a lubricating base oil is added to form a grease. When a lubricating base oil is used as the solvent, it may be used as it is as grease.

In the grease composition of the present invention, the content of component (A) as 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, while if the content of the component (A) exceeds the above range, it becomes too hard as grease and exhibits sufficient lubrication 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]

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

[0034] The grease of the present invention can contain additives that further improve its performance without impairing its performance. As this additive, for example, metal soap, Benton, other gelling agents such as silica gel, chlorine-based, sulfur-based, phosphorus-based, extreme pressure agents such as zinc dithiophosphate, fatty acids, animal oils, oily agents such as vegetable oils, 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 Hereinafter, the contents of the present invention will be described more specifically with reference to examples and comparative examples. Synthesis Example 1 Diphenylmethane-4,4 ′ diisocyanate 8.08
g in 174 g of mineral oil (@ 40 ° C., 100 cSt)
The mixture was heated to 0 ° C. and uniformly dissolved. A mixture of 8.70 g of octadecylamine and 3.2 g of cyclohexylamine dissolved by heating was added thereto, and the mixture was stirred vigorously to immediately produce a gel-like substance. 3 at 100 ° C with continuous stirring
After holding for 0 minutes, adding 6 g of an antioxidant, stirring well, and then passing through a roll mill, the desired grease was obtained. 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
With 100 g of poly-α-olefin oil (@ 40 ° C., 44
cSt) and uniformly dissolved at room temperature. To this, 1.97 g of cyclohexylamine and 11.10 of laurylamine were added.
g was mixed and dissolved in the same poly-α-olefin oil, and the mixture was stirred vigorously to immediately produce a gel-like substance. When the temperature was raised to 80 ° C. by heating, the mixture was passed through a roll mill, and the desired grease was obtained. The ratio of cyclohexyl group / dodecyl group of the resulting diurea compound was 25/75, and the content of the gelling agent was 10 wt%.

Synthesis Example 3 11.96 g of vitriylene diisocyanate was placed in 180 g of polyphenyl ether (@ 40 ° C., 67 cSt), and
It was uniformly dissolved at 0 ° C. A mixture of 7.0 g of cyclohexylamine and 1.04 g of octylamine was added thereto, and the mixture was homogenized. A vigorous stirring produced a gel immediately. After the temperature was raised to 120 ° C. while stirring for 30 minutes, the mixture was passed through a roll mill to obtain the desired grease. The ratio of cyclohexyl group / octyl group of the produced diurea compound was 90/10, and the content of the gelling agent was 10% by weight.

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 be uniformly dissolved. 6.11 g of octadecylamine, 2.25 g of cyclohexylamine and 3.52 g of dicyclohexylamine were added to the mineral oil 60.
g was heated and dissolved, and the mixture was stirred vigorously. As a result, a gel-like substance was immediately formed. After maintaining at 100 ° C. for 30 minutes while continuing stirring, the desired grease was obtained by passing through a roll mill. The ratio of octadecylamino group / cyclohexylamino group / dicyclohexylamino group of the resulting diurea compound was 35/35/30, and the content of the gelling agent was 10% by weight.

Synthesis Example 5 40.3 g of 2,4-2,6-tolylene diisocyanate
In 100 g of mineral oil (@ 210 ° F., 10.5 cSt) and uniformly dissolved at room temperature. To this, 32.1 g of cyclohexylamine and octadecyl alcohol
6 g of the same mineral oil in 390 g of the same mineral oil was added, and the mixture was stirred vigorously to immediately produce a gel-like substance. Hold for 30 minutes while continuing to stir, and raise the temperature to 10.
After the temperature was raised to 0 ° C., the product was passed through a roll mill to obtain the desired grease. The ratio of cyclohexylamino group / octadecyloxy group of the formed urea / urethane compound is 7
At 0/30, the gelling agent content was 11% by weight.

Example 1, Comparative Examples 1 to 6 The component (B) was added to the base grease obtained in the above synthesis examples to obtain a grease having the composition shown in Table 1 (Example 1).
For further comparison, using the above base grease, (B)
Table 1 also 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 performed using a Fafner friction oxidation tester in accordance with ASTM G-III-12. 51204 was used as the bearing, 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) was not blended (Comparative Examples 1 to 5), the composition of the present invention was significantly inferior in fretting resistance. Grease conventionally known to have excellent fretting resistance (Comparative Example 6)
Are also inferior to the composition of the present invention in fretting resistance.

As described above, the grease composition of the present invention comprises:
It is a grease composition that is more excellent in fretting resistance than conventionally known greases.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location C10N 40:00 40:02 50:10

Claims (4)

(57) [Claims] 1. A compound or a compound 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, in a mineral oil-based and / or synthetic lubricating base oil. A grease comprising a gelling agent comprising a mixture of at least two kinds of compounds, 2 to 25% by weight, and (B) 0.2 to 5.0% by weight of diphenyl hydrogen phosphite as essential components. Composition. 2. The gelling agent according to the general formula (1) (Wherein, R ¹ is a divalent aromatic hydrocarbon group having 6 to 15 carbon atoms, and 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 diurea compound having a derivative group or an alkyl group or an alkenyl group having 8 to 20 carbon atoms), and a content of a cyclohexyl group or a derivative group thereof [{(cyclohexyl group or (The number of the derivative groups) / (the number of the cyclohexyl groups or the derivative groups + the number of the alkyl groups or the alkenyl groups)｝ × 100] is 20 to 90%, and R ² is a cyclohexyl group or a derivative group thereof; And a compound in which R ³ is an alkyl group or an alkenyl group is 10 mol%
The composition according to claim 1, comprising a mixture containing the above. 3. The gelling agent represented by the general formula (2): (Wherein, R ⁴ is a divalent aromatic hydrocarbon group having 6 to 15 carbon atoms, and A and B may be the same or different;
An amino group represented by R ⁵ —NH— (R ⁵ represents a cyclohexyl group, a cyclohexyl derivative group having 7 to 12 carbon atoms, or an alkyl group having 8 to 20 carbon atoms), or R ⁶ R ⁷ N- (wherein R ⁶ and R ⁷ may be the same or different and each represents a cyclohexyl group or a cyclohexyl derivative group having 7 to 12 carbon atoms). It consists of at least two or more of a mixture of diurea compounds, and amino group R ⁶ R ⁷ N-content of in the gellant
[{The number of amino groups R ⁶ R ⁷ N − / (the number of amino groups R ⁵ —NH— + the number of amino groups R ⁶ R ⁷ N −)} × 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 a derivative thereof to the number of amino groups R ⁵ —NH— in which R ⁵ is an alkyl group is １ ／. ~ 4 /
The composition according to claim 1, which is 1. 4. The method according to claim 1, wherein the gelling agent comprises 20 to 95 mol% of a diurea compound represented by the general formula (3): Urea / urethane compound 4 represented by the general formula (4)
３０30 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 a divalent aromatic hydrocarbon group having 6 to 15 carbon atoms is represented by R
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. And 20 alkyl groups or alkenyl groups, respectively. ) And the total number of amino groups R ⁹ NH—, R ¹⁰ NH—, and R ¹² NH— in the mixture and the sum of the alkoxy groups R ¹³ O—, R ¹⁵ O—, and R ¹⁶ O— The composition according to claim 1, comprising a urea / urethane mixture having a number ratio of 95/5 to 40/60.