WO2003091367A1

WO2003091367A1 - Grease composition

Info

Publication number: WO2003091367A1
Application number: PCT/JP2003/005114
Authority: WO
Inventors: Hirotsugu Kinoshita; Souichi Nomura; Takashi Arai; Kiyomi Sakamoto
Original assignee: Nippon Oil Corporation
Priority date: 2002-04-26
Filing date: 2003-04-22
Publication date: 2003-11-06
Also published as: JP2003321692A; EP1500693A1; US20060052257A1; AU2003235354A1; EP1500693A4

Abstract

A grease composition comprising a lube base oil, three diurea compounds, and an organomolybdenum compound, wherein the contents of the three diurea compounds satisfy a specific requirement and the content of the organomolybdenum compound is 0.1 to 20 wt.% based on the whole grease composition.

Description

Itoda »

Grease composition

Technical field

The present invention relates to a grease composition, and more particularly, to a grease composition suitably used for constant velocity joints, bearings for continuously variable transmissions, bearings for automobiles and railway vehicles, and the like.

Background art

Lubricants are used for various mechanical parts where metals come into contact with each other, such as constant velocity joints for transmitting driving force from the mission of automobiles to tires, bearings for continuously variable transmissions such as automobiles, and axle bearings for automobiles and railway vehicles. As grease.

The grease used for these various mechanical parts is required to suppress the temperature rise, especially at the beginning of use, from the viewpoint of extending the life, and to reduce the friction from the viewpoint of extending the life and saving energy.

As a method for suppressing the temperature rise, it is generally used to lower the kinematic viscosity of the grease base oil. As a method for reducing friction, various additives such as an organic molybdenum compound and an organic zinc compound are used. It is known to use.

Disclosure of the invention

However, it is very difficult to achieve both the suppression of temperature rise in the initial stage of use and the reduction of friction at the same time by the above-mentioned conventional method. For example, if the kinematic viscosity of the base oil is reduced to suppress the temperature rise at the beginning of use, the oil film becomes thinner and the metals are more likely to come into contact with each other, which tends to increase friction and wear. In addition, there is a concern that the service life will decrease at high temperatures.

In addition, especially in the situation where the load is increasing due to the recent increase in performance and miniaturization of various mechanical parts such as constant velocity joints, bearings for continuously variable transmissions, and axles for automobiles and railway vehicles. However, the characteristics required for grease in terms of suppressing the temperature rise in the initial stage of use and reducing friction are increasing more and more. The present invention has been made in view of the above-mentioned problems of the related art, and an object of the present invention is to provide a grease composition capable of suppressing a rise in temperature in an early stage of use and reducing friction at a high level.

The present inventors have conducted intensive studies to achieve the above object, and as a result, a grease composition in which a specific diurea compound and an organic molybdenum compound are blended in a lubricating base oil in a predetermined blending ratio, respectively, has a constant velocity joint. The present inventors have found that bearings for stepped transmissions, bearings for axles for automobiles and railway vehicles, suppress the temperature rise in the initial stage of use and reduce friction, and have completed the present invention.

That is, the grease composition of the present invention contains a lubricating base oil, a diurea compound represented by the following general formulas (1) to (3), and an organic molybdenum compound, and the following general formula (1) to ( The content of each of the diurea compounds represented by 3) satisfies the conditions represented by the following formulas (4) and (5), and the content of the organic molybdenum compound is 0.1 to 20 based on the total amount of the grease composition. % By mass.

0 o

— HC II (2)

R _Λ ¹ — NH— R ₂ ² —— NHC IINH— R ³ ,

O O

(3)

R ³ —— HCNH— R ² HCHC R ³

[In the formulas (1) to (3), R ¹ represents an aromatic ring-containing hydrocarbon group, R ² represents a divalent hydrocarbon group, and R ³ represents an alicyclic ring-containing hydrocarbon group.]

0.1 ≤ (Wj + 0.5 x W ₂ ) / (W ₁ + W ₂ + W ₃ ) ≤ 1.0 (5) [In the formulas (4) and (5), W ₂ and W ₃ are the content ratios of the diurea compounds represented by the general formulas (1) to (3), respectively, based on the total amount of the grease composition. % By mass). ]

BRIEF DESCRIPTION OF THE FIGURES

1A and 1B are a perspective view and a top view showing a test piece used for a friction test, respectively.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, preferred embodiments of the present invention will be described in detail.

The lubricating base oil used in the grease composition of the present invention includes mineral oil and z or synthetic oil.

Examples of such mineral oils include those obtained by a method usually used in a lubricating oil production process in the petroleum refining industry, and more specifically, a lubricating oil fraction obtained by subjecting crude oil to atmospheric distillation and vacuum distillation. Solvent dewaxing, solvent extraction, hydrocracking, solvent dewaxing, contact dewaxing, hydrorefining, sulfuric acid washing, and purification by performing one or more treatments such as clay treatment.

Further, polybutene Specific examples of the synthetic oils, 1-OTA Ten oligomer, 1 over de Sen'ori sesame Chief of Helsingborg _a Orefin or hydrides thereof; Jitorideshirugu Rutareto, Kishiruaji Bae over preparative to di-2 Echiru, Jiisodeshiruaji base one DOO Diesters such as dito-V-decyl adipate and di-3-ethylhexyl sebacate; trimethylolpropane caprylate, trimethylolpropaneperargonate, pentaerythritol, 2-ethylinohexanoate, and pentaerythri tonoleperanoregone Polyesters such as phosphates; Aromatic ester oils such as trioctyl trimellilate, tridecyl trimellilate, and tetraoctyl viromellitate; Complexes that are esters of mixed fatty acids of dibasic acids and monobasic acids with polyhydric alcohols Stearyl / Les; § Honoré Kino Les naphthalene; § Honoré Kino Les benzene; poly O xylene polyalkylene glyceryl Konore; polyphenyl ether; dialkyl diphenyl Eni Honoré ether Honoré; silicone oil; Or a mixture thereof.

The kinematic viscosity at 100 ° C. of these lubricating base oils is preferably ² to 40 mm ² / s, more preferably 3 to 2 Omm ² / s. The viscosity index of the base oil is preferably 90 or more, and more preferably 100 or more.

In the present invention, the diurea compounds represented by the following general formulas (1) to (3) are added to the lubricating base oil as a thickener. o o

R ₁ ¹ —— HC IINH— R ₂ ² —— N II, (1)

HCNH- R ¹

0 o

(2)

R ¹ —— HCNH— R ² HCHC—— R ³

O O

R _{³ 3} NHC I! NH one R ² one NH II, (3)

CNH in one R ³ above formula (1) ~ (3), R 1 represents an aromatic ring-containing hydrocarbon group. Examples of such a group include a phenyl group, a naphthyl group, and an alkylaryl group in which these groups are substituted with one or more alkyl groups, and an aryl group such as a phenyl group and a naphthyl group. And an arylalkyl group substituted with a group.

The number of carbon atoms in the aromatic ring-containing hydrocarbon group represented by R ¹ is not particularly limited, but those having 7 to 12 carbon atoms are preferably used. Specific examples of the aromatic ring-containing hydrocarbon group having such a carbon number include a tolyl group, a xylyl group, a monophensyl group, a t-butylphenyl group, a dodecylphenyl group, a benzinole group, a methylbenzyl group, and the like. Can be

Further, R ² in the general formulas (1) to (3) represents a divalent hydrocarbon group (preferably a divalent hydrocarbon group having 6 to 20, and particularly preferably 6 to 15 carbon atoms). This Examples of such a hydrocarbon group include a linear or branched alkylene group, a linear or branched alkenylene group, a cycloalkylene group, and an aromatic group. Of these, an ethylene group, a 2,2-dimethyl-4-methylhexylene group and groups represented by the following formulas (6) to (14) are preferable, and groups represented by the formulas (7) and (9) are preferable. Particularly preferred.

H ₃ C, / CH ₃

(8)

(9)

(12)

In general formulas (2) and (3), R ³ represents an alicyclic ring-containing hydrocarbon group. The number of carbon atoms of the alicyclic ring-containing hydrocarbon group represented by R ³ is not particularly limited, but those having 7 to 12 are preferably used.

As the alicyclic ring-containing hydrocarbon group represented by R ³ , a cyclohexyl group or an alkylcyclohexyl group is preferably used. Specifically, methylcyclohexyl group, dimethylcyclohexyl group, ethynolecyclohexyl group, ethylcyclohexyl group, propylcyclohexyl group, isopropylcyclohexyl group, 1-methyl-3-propylpropyl group Hexyl group, butylcyclohexyl group, pliers / resin mouth, hexyl group, pentylmethylcyclohexyl group, hexylcyclohexyl group, etc., among them, cyclohexyl group, methylcyclohexyl group, dimethyl mouth Hexyl group and ethylcyclohexyl group are more preferable.

The content ratio of each of the diurea compounds represented by the general formulas (1) to (3) needs to satisfy the conditions represented by the following formulas (4) and (5).

5≤W + W ₂ + W ₃ ≤ 30 (4)

0.1 ≤ (Wj + O. 5 XW ₂ ) / (W ^ W ^ Ws) ≤ 1-0 (5)

[In the formulas (4) and (5), W ₂ and W ₃ are the content ratios of the diurea compounds represented by the general formulas (1) to (3) based on the total amount of the grease composition. % By mass). ]

As shown in the formula (4), the sum of the content of the diurea compounds represented by the general formulas (1) to (3) + W ₂ + W ₃ is 5 to 30% by mass based on the total amount of the grease composition. so is there. If Wi + Ws + Ws is less than 5% by mass, the effect as a thickening agent is small and the grease will not be sufficient, for the same reason.

Is preferably 10% by mass or more. On the other hand, if Wi + Ws + Wg exceeds 30% by mass, the grease becomes too hard to exhibit sufficient lubrication performance, and for the same reason, it is ^ + Ws + W ^ S 0 mass. / ₀ or less is preferable.

Also, 5 XW ₂ ) /

If the value is less than 0.1, the effect of suppressing the temperature rise in the initial stage of use becomes small. For the same reason, (W _x +0.5 XW ₂ ) / (W _x + W ₂ + W3) is preferably 0.2 or more, more preferably 0.3 or more, and 0.4 or more. Is more preferable. From the viewpoint of the effect of suppressing similarly used initial temperature _{rise, + 5 XW 2) / (} W ^ W ^ Wa) is preferably is 0.7 or less, more preferably that it is a less than 0.55 , More preferably less than 0.5.

The urea thickening agent generally has the property of becoming hard with time, but the grease composition of the present invention is relatively hard to harden. However, (W + 0.5 XW ₂ ) / (W _x + W ₂ + W ₃ ) in the equation (5) is preferably 0.3 or more because it becomes harder to harden. It is more preferably at least, more preferably at least 0.4, particularly preferably at least 0.45.

These diurea compounds include, for example, a diisocyanate represented by the general formula OCN—R ² —NCO and an amine represented by the general formula R ¹ —NH ₂ and / or R ³ —NH ₂ in a base oil. 0-200. It is obtained by reacting with C. At this time, RR ² and R ³ correspond to R ¹ R ² and R ³ in the general formulas (1) to (3).

Also, +5 XW ₂ ) Z in the general formula (5)

If the value of is not 1, the mixture of the reaction of diisocyanate with the amine represented by R ¹ — NH ₂ and the reaction of diisocyanate with the amine represented by R ³ — NH May be a thing, Amin and R ³ represented by Jiisoshianeto and R 1 one NH ₂ - or may be obtained by reacting a mixture of amines represented by NH _2.

The grease composition of the present invention further contains an organic molybdenum compound in addition to the lubricating base oil and the diurea compound. Examples of such an organic molybdenum compound include a derivative of phosphoric acid or thiophosphoric acid ester represented by the following general formula (15), and a derivative of a dithiopotamyl ester represented by the following general formula (16). .

Mo _b X _c (15)

_{R s} -so _b X _c (16)

In the general formulas (15) and (16), R may be the same or different, each represents a hydrocarbon group having 1 or more carbon atoms, and c Xs may be the same or different, Each represents an oxygen atom or a sulfur atom, and a, b, and c each represent an integer of 1 to 6.

In the above formulas (15) and (16), examples of the hydrocarbon group represented by R include an alkyl group having 1 to 24 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, and a carbon atom having 6 to 11 carbon atoms. An alkylaryl group having 6 to 18 carbon atoms, an alkylaryl group having 7 to 24 carbon atoms, and an arylalkyl group having 7 to 12 carbon atoms.

Examples of the alkyl group include a methyl group, an ethyl group, a propyl group (including all branched isomers), a butyl group (including all branched isomers), a pentyl group (including all branched isomers). Hexyl group (including all branched isomers), heptyl Tyl group (including all branched isomers), octyl group (including all branched isomers), nonyl group (including all branched isomers), decyl group (including all branched isomers) ), Decyl group (including all branched isomers), dodecyl group (including all branched isomers), tridecyl group (including all branched isomers), tetradecyl group (including all branched isomers) Pentadecyl group (including all branched isomers), hexadecyl group (including all branched isomers), heptadecyl group (including all branched isomers), octadecyl group (including all branched isomers) Nonadecyl group (including all branched isomers), icosyl group (including all branched isomers), henicosyl group (including all branched isomers), docosyl group (including all branched isomers) All branched isomers Including), including tricosyl (all branched isomers), including tetracosyl group (all branched isomers), etc. can be mentioned.

Specific examples of the cycloalkyl group include a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group.

Specific examples of the alkylcycloalkyl group include a methylcyclopentyl group (including all substituted isomers), an ethylcyclopentyl group (including all substituted isomers), and a dimethylcyclopentyl group (including all substituted isomers). Protyl cyclopentyl group (including all branched and substituted isomers), methylethylcyclopentyl group (including all substituted isomers), trimethylcyclopentyl group (including all substituted isomers) ), Butylcyclopentyl group (including all branched and substituted isomers), methylpropyl cyclopentyl group (including all branched and substituted isomers), getylcyclopentyl group (including all substituted isomers) ), Dimethylethyl pentyl group (including all substituted isomers), Hexyl group (including all substituted isomers), ethyl-hexyl group (including all substituted isomers), dimethyl-cycle hexyl group (including all substituted isomers), propyl-cycle hexyl Group (including all branched isomers and substituted isomers), methylethylcyclohexyl group (including all substituted isomers), trimethylcyclohexyl group (including all substituted isomers) ), Butylcyclohexyl group (including all branched and substituted isomers), methylpropyl cyclohexyl group (including all branched and substituted isomers), Xyl group (including all substituted isomers), dimethylethylcyclohexyl group Xyl group (including all substituted isomers), methylcycloheptyl group (including all substituted isomers), ethylcycloheptyl group (all Dimethyl heptyl group (including all substituted isomers), propyl cyclyl heptyl group (including all branched isomers and substituted isomers), methylethylcyclo Heptyl group (including all substituted isomers), trimethylcyclyl heptyl group (including all substituted isomers), butylcycloheptyl group (all branched isomers, substituted isomers) ), Methylpropylcycloheptyl group (including all branched isomers and substituted isomers), getylcycline heptyl group (including all substituted isomers), and dimethylethylcycloheptyl group (including all isomers). And all substituted isomers).

Specific examples of the aryl group include a phenyl group and a naphthyl group.

Specific examples of the alkylaryl group include a tolyl group (including all substituted isomers), a xylyl group (including all substituted isomers), and an ethylfuryl group (including all substituted isomers). ), Propylfuryl group (including all branched and substituted isomers), methylethylphenyl group (including all substituted isomers), trimethylphenyl group (including all substituted isomers) , Butylphenyl group (including all branched isomers and substituted isomers), methylpropylphenyl group (including all branched isomers and substituted isomers), getylphenyl group (including all substituted isomers) , Dimethylethyl phenyl group (including all substituted isomers), pentylphenyl group (including all branched isomers and substituted isomers), hexylphenyl group (including all branched isomers) Isomers, substituted isomers), heptyl (including all branched and substituted isomers), octylphenyl (including all branched and substituted isomers), nonylphenyl (including all isomers) Branched isomers and substituted isomers), decylphenyl group (all branched isomers) Didecylphenyl group (including all branched isomers and substituted isomers), dodecylphenyl group (including all branched isomers and substituted isomers), tride Silphenyl group (including all branched and substituted isomers), tetradecinolefuunyl group (including all branched and substituted isomers), pentadecylphenyl group (including all branched and substituted isomers) Hexadecylphenyl group (including all branched and substituted isomers), heptadecylphenyl group (including all branched and substituted isomers), octadecylphenyl group (including All branched isomers and substituted isomers).

Examples of the arylalkyl group include a benzyl group, a phenethyl group, a phenylpropyl group (including all branched isomers), and a phenylbutyl group (including all branched isomers).

Specific examples of the compounds represented by the general formulas (15) and (16) include molybdenum phosphate, molybdenum thiophosphate, molybdenum dithiophosphate, molybdenum dithiocarbamate, and the like.

Phosphoric acid or thiophosphoric acid ester derivatives represented by the following general formula (15) and dithiol rubamic acid ester derivatives represented by the following general formula (16) are usually phosphoric acid esters or thiophosphoric acid esters. It is a compound obtained by reacting dithiocarbamic acid ester with an inorganic molybdenum compound (molybdenum trioxide, molybdic acid or a salt thereof), if necessary, together with a sulfur source.

Since molybdenum can have various valences, usually, the compound obtained by the above reaction is a mixture. Among them, the most typical compounds include compounds represented by the following formulas (17) and (18).

X X ,, X X

X ヽ

R-X ---- I PI-X- I-Re M IIo- X- I PI-X-R (17)

I I \ / I I

R-XX-R

Further, as the organic molybdenum compound in the present invention, only the compound represented by the general formula (15) may be used, or only the compound represented by the general formula (16) may be used. However, both may be used as a mixture. However, when used as a ballast for bearings, the compound represented by the above general formula (16) is preferable because of its superior thermal stability.

The content ratio of the organic molybdenum compound in the present invention is 0.1% by mass or more, preferably 0.5% by mass / ₀ or more based on the total amount of the Darryce composition. The content is 20% by mass or less, preferably 10% by mass or less. When the content of the organic molybdenum compound is less than 0.1% by mass, the effect of reducing the friction of the grease is not sufficient, and when it exceeds 20% by mass, the effect of reducing the friction is commensurate with the amount added. I can't get it.

Further, in the grease composition of the present invention, in order to improve fretting resistance, it is preferable to mix one or more compounds selected from the group consisting of paraffin oxides and phosphorus compounds. When these compounds are blended, a higher level of fretting resistance can be achieved over a long period of time, particularly in constant velocity joints in which fine movement wear (fretting) is likely to be a problem due to minute reciprocating movement.

Examples of the oxidized paraffin used in the present invention include oxidized paraffin, oxidized paraffin salts, and oxidized paraffin esters. As the oxidized paraffin mentioned here, no. Examples thereof include those obtained by oxidizing petroleum waxes such as raffin wax, microcrystalline wax and slack wax, and synthetic waxes such as polyolefin wax. Examples of the salt of paraffin oxide include alkali metal salts, alkaline earth metal salts, and amine salts of the above paraffin oxide. I can do it. Examples of the ester of oxidized paraffin include an ester of an alcohol (most preferably methanol) having 1 to 24 (preferably 1 to 12, more preferably 1 to 6) carbon atoms and the above paraffin oxide. The properties of the oxidized paraffins used in the present invention are arbitrary, but from the viewpoint of fretting resistance, the melting point is preferably 25 ° C or higher, more preferably 30 ° C, and preferably 110 ° C. It is below 70 ° C, more preferably below 70 ° C. The total acid value is preferably at least 0.2 mg KOH / g, more preferably at least 1 mg KOH / g, and at most 65 mg KOHZg, more preferably at most 40 mg KOH / g. Specific examples of the phosphorus compound include a phosphoric acid ester, an acidic phosphoric acid ester, an amine salt of an acidic phosphoric acid ester, a chlorinated phosphoric acid ester, a phosphite, and a thiophosphoric acid ester. These phosphorus compounds are esters of phosphoric acid, phosphorous acid or thiophosphoric acid with alkanols, polyether alcohols or derivatives thereof.

More specifically, the phosphoric acid esters include tributyl phosphate, tripentinole phosphate, trihexyl phosphate, triheptinole phosphate, tri-octinole phosphate, trinoel phosphate, and tridecino. Rephosphate, tridecyl phosphate, tridodecyl phosphate, tritridecyl phosphate, tritetradecyl phosphate, tripentadecinolephosphate, trihexadecyl phosphate, trihexadecyl phosphate, trioctadecyl phosphate, trioctadecyl phosphate , Trioleyl phosphate, triphenyl phosphate, tricresinole phosphate, trixyleninole phosphate, cresinole diphenyl phosphate, xylenyl diphenyl phosphate and the like. It is.

Examples of the acidic phosphoric acid ester include monobutyl acid phosphate, monopentinoleic acid phosphate, monohexinoleic acid phosphate, monoheptyl acid phosphate, monooctinoleic acid phosphate, monononinoleic acid phosphate, monodecinoleic acid phosphate, Monoundecyl acid phos Fate, monododecylacid phosphate, monotridecylacid phosphate, monotetradecylacid phosphate, monopentadecylacid phosphate, monohexadecinoleate acid phosphate, monoheptadecyl acid phosphate, monoacid acid phosphate. , Mono-leinoreacid phosphate, dibutinoreacid phosphate, dipentinoreacid phosphate, dihexylacid phosphate, diheptylacid phosphate, dioctylacid phosphate, dinonylacid phosphate, didecylacid phosphate, didecyl phosphate acid phosphate Didodecyl acid phosphate, ditridecyl acid phosphate, Tiger decyl acid phosphate Feto, di pentadecyl Acid phosphatase We over preparative, Kisadeshiruashi' to di Dohosu Hue Ichito, di heptadecyl § Sit Dohosufueto, di O Kuta Desi Honoré § Cid phosphite Feto, Jioreiruashi' Dohosufeto and the like.

Examples of the acid phosphate ester amine salt include the above-mentioned acid phosphate methylamine, ethylamine, propynoleamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, dimethylamine, getylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine. And diheptylamine, dioctylamine, trimethylamine, triethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, triheptylamine, trioctylamine, and other salts with an amine such as trioctylamine. Examples of the chlorinated phosphoric acid ester include tris'dichloropropyl phosphate, tris'chloroethynolephosphate, tris.chlorophenophosphate, polyoxyalkylene bis [di (chloroalkyl)] phosphate, and the like. Can be Examples of phosphites include dibutyl hydrogen phosphite, dipentyl hydrogen phosphite, dihexyl hydrogen phosphite, diheptinol hydrogen phosphite, dioctinole hydrogen phosphite, and dinoninoleno. Didrogen phosphite, didecinole hydrogen phosphite, didecylha Phosphorous diesters such as idrogen phosphite, didodecyl hydrogen phosphite, dioleno hydrogen phosphite, diphenyl hydrogen phosphite, digrezinole hydrogen phosphite, tributyl phosphite, tripentyl Phosphite, trihexyl phosphite, triheptyl phosphite, trioctyl phosphite, trinonyl phosphite, tridecyl phosphite, triundecyl phosphite, tridodecyl phosphite, trioleyl Examples include phosphites, such as phosphites, triphenyl phosphites, and tricresyl phosphites.

Phosphorothionates include tributylphosphorochonate, tripentinolephosphorochonate, trihexynolefosfolotionate, triheptinolephosphorochonate, trioctinolephosphorochonate, and trinonylphosphonate. Forotionate, Tridecinolephosphorochonate, Tridindecylphosphorochonate, Tridodecylphosphorochonate, Tritridecylphosphorochonate, Tritetradecylphosphorochonate, Tripentadecinophorosphorotionate Nitrate, trihexadecinolephosphorotionate, triheptadecinolephosphorochonate, trioctadecylphosphorochonate, trioleylphosphorochonate, triffe Binorefosfolonate, Tricresinolefofofonate, Trixyleninolefosfofonate, Cresinoresifenorenofofofonate, Xyleninores phen-norefosfofonate, Tris (n-propinolephenyl) phosphorofonate Enil) Phosphorothionate, Tris (n-butynolephenol) Phosphorotionate, Tris (Isoptinolephenyl) Phosphorotionate, Tris (s-Butylphenylenole) Phosphorotionate, Tris (t-butylphenyl) Phosphoro Forotionate and the like. One of the above phosphorus compounds may be used alone, or two or more thereof may be used in combination. Of these, phosphites are preferred, phosphite diesters are more preferred, and diphenylhydrogen phosphites are even more preferred, because they are more excellent in fretting resistance.

The content of one or more compounds selected from the group consisting of oxidized paraffins and phosphorus compounds is preferably 0.5 mass based on the total amount of the grease composition. / ₀ or more, more preferably 1.0% by mass or more. If the content is less than 0.5% by mass, the fretting resistance of the grease tends to be insufficient. The content ratio is preferably 15% by mass or less, more preferably 10% by mass. If the content ratio exceeds 15% by mass, fretting resistance cannot be obtained in proportion to the added amount.

Further, in order to further improve the fretting resistance, it is necessary to obtain (W ₁ +0.5 XW ₂ ) /

+ Wg) is preferably ◦.3 or more, more preferably 0.35 or more, still more preferably 0.4 or more, even more preferably 0.45 or more, Further, it is preferably 0.7 or less, more preferably 0.6 or less, and even more preferably less than 0.5.

In the grease composition of the present invention, solid lubricants, extreme pressure agents, antioxidants, oil agents, rust inhibitors, A viscosity index improver or the like can be contained.

Specific examples of the solid lubricant include graphite, graphite fluoride, polytetrafluoroethylene, molybdenum disulfide, antimony sulfide, and alkali (earth) metal borate.

Specific examples of the extreme pressure agent include organic zinc compounds such as zinc dialkyldithiophosphate and zinc diaryldithiophosphate; sulfur-containing compounds such as dihydrocarbyl polysulfide, sulfurating ester, thiazole compound, and thiadiazole compound. And the like. Specific examples of the antioxidant include phenolic compounds such as 2,6-di-t-butylphenol and 2,6-di-t-butyl-p-cresol; dialkyldiphenylenoamine, phenyl- _α -naphthylamine, and ρ-a. Examples include amine compounds such as nolequinolefeninolehina phthylamine; sulfur compounds; phenothiazine compounds.

Specific examples of the oil decaying agent include amines such as laurylamine, myristylamine, palmitylamine, stearylamine, oleylamine, etc .; Higher alcohols such as oleic acid, oleyl alcohol; higher fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid; methyl laurate, methyl myristate, methyl palmitate, methyl stearate, oleic acid Fatty acid esters such as methyl; amides such as lauryl amide, myristinoleamide, palmityl amide, stearyl amide and oleyl amide; oils and fats.

Specific examples of the stopping agent include metal soaps; polyhydric alcohol partial esters such as sorbitan fatty acid esters; amines; phosphoric acid; and phosphates.

Specific examples of the viscosity index improver include polymethacrylate, polyisobutylene, and polystyrene.

To prepare the grease composition of the present invention, for example, a lubricating base oil may be prepared by adding a compound represented by the general formula (1)

It can be obtained by mixing and stirring the diurea compound and the organic molybdenum compound represented by the following formulas (3) and, if necessary, other additives, and passing through a roll mill or the like. Also, the raw material components of the diurea compounds represented by the general formulas (1) to (3) are added to a lubricating base oil in advance, melted, stirred and mixed to prepare the diurea compound, and then the organic molybdenum compound is added. It can also be manufactured by mixing and stirring other additives according to the conditions and passing through a roll mill or the like. Since the grease composition of the present invention is excellent in suppressing temperature rise and reducing friction, grease for various gears for constant velocity joints, constant velocity gears, transmission gears, and various bearings for ball bearings, roller bearings, and the like. It is particularly preferably used for constant velocity joints, bearings for continuously variable transmissions, gears and bearings for steelmaking facilities, and axle bearings for automobiles and railway vehicles.

[Example]

Hereinafter, the content of the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

(Examples 1 to 7 and Comparative Examples 1 to 5)

Using poly-α-olefin (kinematic viscosity at 40 ° C: 48 mm ² Zs) as a lubricating base oil, diphenylmethane-1,4'-diisocyanate (MDI) is heated and dissolved in the base oil. To this was added a monoamine described in Table 1 or Table 2 which was dissolved by heating in the same base oil. After adding the various additives shown below to the formed gel substance so as to have the compositions shown in Table 1 or Table 2, respectively, stirring the mixture, the mixture was passed through a roll mill, and Examples 1 to 7 and Comparative Examples 1 to 5 were added. Grease composition was obtained. The value of W + Ws + Ws and in each grease composition _{_{(W x + 0. 5 XW 2}} ) / (W x + W 2 + W 3) shown in Table 1 and Table 2. In Table 2, the column of Wi + Ws + Wg in Comparative Examples 4 and 5 shows not the total amount of Wi + Ws + Wg but the total amount of increasing agent.

Additive:

MoDTC (Molybdenum Dioctyl Dicarbamate)

Mo DTP (Molybdenum Dioctyl Phosphate)

Mo P (Molybdenum dibutyltin phosphate)

Boron friction modifier (boric acid-based friction modifier)

Oxidized paraffins (Oxidized paraffin esters (esters of oxidized paraffin and methanol obtained by oxidizing slack wax, total acid value: 33 mg KOHZnig, saponification value: 130 kg KOH / g)) Zinodidrogen phosphite (diphenyl hydrogen phosphite). The grease compositions of Examples 1 to 7 and Comparative Examples 1 to 6 were subjected to the following temperature rise test and friction test.

(Temperature rise test)

4.0 g of grease is filled in a deep groove ball bearing of inner ring ψ 55 mm, outer ring ψ 90 mm, width 11 mm, and the bearing is rotated under the conditions of inner ring rotation speed of 9000 rpm and axial load of 500 ON. The temperature of the bearing outer ring was measured and the temperature rise Δ 上昇 was determined. The obtained results are shown in Tables 1 and 2. 1A and 1B are a perspective view and a top view showing a test piece used for a friction test, respectively. As shown in the figure, after filling 1 g of the grease composition into the needle holder 2 (14 mm X 1 OmmX 2.5 mm) formed in the center of the lower disc 1 (<i> 24 mm X 7.9 mm), Three 21 dollars (φ 3 mm X 13.8 mm) were stored in the holder 2, and the upper disk 4 (2 O mm X 13 mm) was placed thereon. The angle 0 [deg] between the straight line 1 passing through the center O of the upper surface of the lower disk 1 and perpendicular to the direction of movement of the upper disk 4 and the straight line 1 ₂ passing through the center O and parallel to the longitudinal direction of the needle 3 These test pieces were set on a SRV friction tester so that the set angle was 3 Odeg, and a friction test was performed under the conditions of a frequency of 40 Hz, an amplitude of 3 mm, a load of 1000 N, and a temperature of 80 ° C. . Tables 1 and 2 show the coefficient of friction after 10 minutes when each grease composition was used.

(Fretting resistance test)

Fuff ^ "Fretting resistance test was performed using a friction oxidation tester in accordance with ASTM D4170, and the amount of wear was measured. Thrust bearing 51204 (manufactured by Nippon Seie Co., Ltd.) The test time was 2 hours and the test temperature was room temperature, and in this test, one day after production of each grease composition was used as a sample. See Table 2. (Measurement of consistency)

The consistency of each of the dalyce compositions of Examples 1 to 7 and Comparative Examples 1 to 6 was measured after one day of production and three months after production. Tables 1 and 2 show the obtained results.

[Table 2]

As shown in Table 1, it was confirmed that the grease compositions of Examples 1 to 8 were excellent in friction characteristics and suppression of temperature rise. Further, the grease compositions of Examples 7 and 8 in which paraffin oxides and phosphorus compounds were combined exhibited a very high level of fretting resistance.

In contrast, the grease composition of Comparative Example 1 shown in Table 2 had insufficient friction characteristics, and the temperature rise was large when the grease compositions of Comparative Examples 2 and 3 were used. .

Industrial applicability '

As described above, according to the grease composition of the present invention, the diurea compound represented by any of the general formulas (1) to (3) and the organic molybdenum compound are blended in the lubricating base oil in a specific blending ratio. Accordingly, it is possible to achieve a high level of suppression of temperature rise in the initial stage of use and reduction of friction.

Claims

Scope of word blue

1. It contains a lubricating base oil, a diurea compound represented by the following general formulas (1) to (3), and an organic molybdenum compound, and is a diurea represented by the following general formulas (1) to (3). A grease composition in which the content of each compound satisfies the conditions represented by the following formulas (4) and (5), and the content of the organic molybdenum compound is 0-1 to 20% by mass based on the total amount of the grease composition. object.

ο ο

R, ¹ —— II ₂ II ₃ (2)

HCNH- R ² one HCNH one R ³

≤ 1.0 (5)

[In formulas (4) and (5), W ₂ and W ₃ represent the content (% by mass) of the diurea compound represented by the general formulas (1) to (3), respectively, based on the total amount of the grease composition. Represents ]