JP2001247888A - Grease composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a grease composition having excellent rust resistance and abrasion resistance. SOLUTION: This grease composition contains at least one base oil selected from mineral oil-based lubricating oil base oils and synthetic lubricating oil base oils, an abrasion-resisting agent comprising molybdenum dithiophosphate, a thickening agent, at least one rust preventive selective from zinc naphthenate, thiadiazole and oxyethylene amine and polyisobutylene.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grease composition having excellent rust prevention and applicable to lubricated parts of automobiles and the like.

[0002]

2. Description of the Related Art Vehicles such as automobiles, trucks, and bicycles are used in various environments, and are exposed to, for example, rainwater or seawater (salt water) when traveling on the seaside.
When used in such an environment, there is a problem that bearings and the like of automobiles and the like are easily rusted and easily worn. Also,
There are similar problems with fishing gear and those used in similar environments. Therefore, rust prevention plays a very important role not only in components such as automobiles, but also in grease used for them. Several greases have been developed for the purpose of improving rust resistance. However, these greases reduce the rust resistance of bearings and other parts due to the ingress of rainwater or seawater (brine) from the outside. There are problems such as easy wear.

[0003]

SUMMARY OF THE INVENTION The present invention has excellent rust prevention and abrasion resistance, and can protect lubricated parts of various parts of automobiles and the like even if rainwater, seawater or the like is mixed. It is intended to provide a grease composition.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies in order to achieve the above object, and as a result, a specific molybdenum dithiophosphate (hereinafter referred to as MoDTP)
Also called. ), Thickener, Zn naphthenate, at least one selected from thiadiazole or oxyethyleneamine and polyisobutylene, when applied to lubricated parts such as automobiles, their rust resistance and wear resistance It has been found that the performance can be improved, and the present invention has been completed. That is, the present invention relates to at least one base oil selected from a mineral oil-based lubricating base oil and a synthetic lubricating base oil, an antiwear agent comprising molybdenum dithiophosphate, a thickener, zinc naphthenate, thiadiazole and oxyethylene amine. A grease composition characterized by containing at least one kind of rust inhibitor selected from the group consisting of: and a polyisobutylene.

The present invention also provides a grease composition wherein the thickener is at least one selected from the group consisting of calcium grease, lithium grease, lithium complex grease, and urea grease. Further, the present invention provides a grease composition wherein the thickener is at least one selected from calcium grease and urea grease, and the rust inhibitor is zinc naphthenate. Hereinafter, the present invention will be described in detail.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The base oil used in the grease composition of the present invention includes mineral lubricating base oils, synthetic lubricating base oils, and mixtures thereof, which are usually used in greases. Various lubricating base oils are used.
The value of the kinematic viscosity at the, 1 to 1000 mm ² / s are preferred, particularly preferably 1 to 500 mm ² / s. Examples of the mineral oil-based lubricating base oil include those obtained by appropriately combining a lubricating oil fraction of crude oil with solvent refining, hydrorefining, or the like.

The synthetic lubricating base oils include, for example, α-olefin oligomers which are polymers of α-olefins having 3 to 12 carbon atoms, sebacates including 2-ethylhexyl sebacate, dioctyl sebacate, azelates, and the like.
C4 to C12 dialkyl diesters such as adipate, 1-trimethylolpropane, polyols including esters obtained from pentaerythritol and C3 to C12 monobasic acids, C9 to C40 alkyl groups Alkyl benzenes having the formula (I), polyglycols such as polyglycol obtained by condensing butyl alcohol with propylene oxide, phenyl such as polyphenyl ether having about 2 to 5 ether chains and about 3 to 6 phenyl groups Ethers and the like. The mineral oil-based lubricating base oil and the synthetic lubricating base oil can be used alone or in combination of two or more. The amount of the base oil can be appropriately selected according to the required properties, but is usually in the range of 60 to 95% by mass, preferably 80 to 95% by mass based on the grease composed of the base oil and the thickener.
The range is 90% by mass.

The thickener used in the grease composition of the present invention is preferably a thickener used for greases such as calcium grease, lithium grease, lithium complex grease and urea grease, and is preferably used for calcium grease and urea grease. The thickeners obtained are particularly preferred. These thickeners may be used alone or in a combination of two or more. The content of the thickener is not particularly limited, but is usually 1 to 1 with respect to the grease composition.
It is 30% by mass, preferably 2 to 20% by mass.
The molybdenum dithiophosphate used in the grease composition of the present invention is represented by the following formula (1).

[0009]

Embedded image

(Wherein R ¹ , R ² , R ³ and R ⁴ are alkyl or alkenyl groups having 1 to 24 carbon atoms, which may be the same or different, and n and m are 1 to 3; And the sum of n and m is 4. In the above formula, the alkyl group or alkenyl group represented by R ¹ , R ² , R ³ , and R ⁴ may be linear or branched, and has the same number of carbon atoms. Is preferably 3 to 24, more preferably 6 to
18, particularly preferably 6 to 16. Specific examples of the alkyl group or alkenyl group include, for example, propyl group, butyl group, pentyl group, isopentyl group, hexyl group, 2-ethylhexyl group, octyl group, nonyl group, decyl group, dodecyl group, tridecyl group, lauryl And the like. Preferred specific examples of molybdenum dithiophosphate include those represented by the following formula (2).

[0011]

Embedded image (In the formula, R ¹ , R ² , R ³ and R ⁴ are the same as described above.) These molybdenum dithiophosphates may be used alone or in combination of two or more. Good. The content ratio of molybdenum dithiophosphate is preferably 0.1 to 20% by mass in the grease composition, and is preferably 0.1 to 20% by mass.
5-15 mass% is more preferable, 1-10 mass% is still more preferable, and 2-8 mass% is especially preferable. If the content of molybdenum dithiophosphate is too small, the abrasion resistance will be insufficient, and the performance will be saturated even if the content of molybdenum dithiophosphate is too large. In the grease composition of the present invention, a rust inhibitor comprising at least one selected from zinc naphthenate, thiadiazole and oxyethyleneamine is used. Of these, zinc naphthenate is preferred. Zinc naphthenate has excellent demulsifying properties when calcium grease or urea grease is used as a thickener. These rust inhibitors are:
Species may be used alone or in combination of two or more. Zinc naphthenate is represented by the following formula (3).

[0012]

Embedded image (Wherein, R ⁵ and R ⁶ are alkyl groups having 1 to 16 carbon atoms, which may be the same or different, and j and k are 1
To 16 and may be the same or different. In the above formula, the alkyl group of R ⁵ and R ⁶ may be linear or branched, and preferably has 1 to 16 carbon atoms.
More preferably, it is 3 to 16, particularly preferably 8 to 16. Specific examples of the alkyl group include, for example, propyl, butyl, pentyl, isopentyl, hexyl, 2-ethylhexyl, octyl, nonyl, decyl, dodecyl, tridecyl, lauryl, and the like. No. j and k are each preferably 1 to 16, and particularly preferably 1 to 9. Only one zinc naphthenate may be used, or two or more zinc naphthenates may be used in combination. The content ratio of zinc naphthenate is preferably 0.1 to 10% by mass, more preferably 0.1 to 7% by mass, further preferably 0.3 to 5% by mass, particularly preferably 0.5 to 4% by mass. is there. Thiadiazole is represented by the following formula (4).

[0013]

Embedded image (In the formula, R ⁷ and R ⁸ are alkyl groups having 1 to 12 carbon atoms, which may be the same or different.) In the above formula, the alkyl group of R ⁷ and R ⁸ may be linear or branched. And the number of carbon atoms is preferably 1 to 10,
Particularly preferred is 1 to 8. Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, an isopentyl group, a hexyl group,
-Ethylhexyl group, octyl group and the like. Preferred specific examples of thiadiazole include, for example, 2,5
-Bis (tertiary octyldithio) 1,3,4-thiadiazole and the like. Thiadiazole is, for example, US
It can be obtained by the production method disclosed in P2719125, P2719126 and the like. One type of thiadiazole may be used alone, or two or more types may be used in combination. The content ratio of thiadiazole is preferably 0.05 to 3.0% by mass, more preferably 0.1 to 2.
0 mass%, more preferably 0.3 to 2.0 mass%, particularly preferably 0.5 to 1.5 mass%. Oxyethyleneamine is represented by the following formula (5).

[0014]

Embedded image (In the formula, R ⁹ is a hydrocarbon group, and x and y are integers.) In the above formula, the hydrocarbon group as R ⁹ may be linear or branched, and the number of carbon atoms is 8 to 18 are preferable, and 8
To 16 are more preferable, and 8 to 12 are particularly preferable. Examples of the hydrocarbon group include an alkyl group, an alkenyl group, an aromatic group, an alicyclic group, and a combination thereof. An alkyl group and an alkenyl group are preferable, and an alkyl group is particularly preferable. Specific examples of the hydrocarbon group include a 2-ethylhexyl group, an octyl group, a decyl group, a dodecyl group, a tridecyl group, a phenyl group, and a cyclohexyl group. x is preferably 0 to 5,
It is more preferably 0 to 3, and particularly preferably 0 to 2. y is preferably 1 to 5, more preferably 1 to 3, and particularly preferably 1 to 2. Oxyethyleneamine may be used alone or in combination of two or more. The content ratio of oxyethyleneamine is preferably 0.05 to 3.0% by mass, more preferably 0.1 to 2.0% by mass, and still more preferably 0.3 to 2.0% by mass.
To 2.0% by mass, particularly preferably 0.5 to 1.5% by mass
It is. Polyisobutylene (hereinafter, also referred to as PIB) used in the grease composition of the present invention is represented by the following formula (6).

[0015]

Embedded image (In the formula, p is an integer.) The number average molecular weight of the polyisobutylene is preferably 30,000 to
It is 100,000, more preferably 30,000 to 80,000, and particularly preferably 30,000 to 70,000. If the number average molecular weight is too small, the adhesion of the grease may be deteriorated, and if the number average molecular weight is too large, the wear resistance may be deteriorated. The content ratio of polyisobutylene is preferably 1 to
It is 30% by mass, more preferably 2 to 20% by mass, further preferably 3 to 18% by mass, particularly preferably 3 to 15% by mass. If the content of polyisobutylene is too low, the adhesion of grease tends to be poor, and if the content of polyisobutylene is too high, wear resistance tends to be poor. The grease composition of the present invention can be adjusted by mixing the above components.

The mixing order of each component is not particularly limited, and may be appropriately added. Grease composed of a base oil and a thickener is adjusted in advance in a grease pot, and the other components are added thereto. Is preferably added and mixed. The grease may be adjusted by a method of simply mixing the base oil and the thickener, but after mixing and dispersing the precursor of the thickener in the base oil, the precursor is reacted to increase the grease. It is preferable to use a method in which a thickener is formed and a thickener is dispersed in a base oil. The grease composition of the present invention preferably contains an antioxidant. Examples of the antioxidant include 2,6-di-tert-butylparacresol, octylated diphenylamine, and phenyl-
α-naphthylamine, 4,4′-tetramethyldiaminodiphenylmethane and the like. The content of the antioxidant is preferably 0.01 to 10% by mass, more preferably 0.05 to 5% by mass, and particularly preferably 0.1 to 3% by mass. Further, other additives can be added to the grease composition of the present invention as long as the object of the present invention is not impaired. The grease composition of the present invention can be used for any lubricating point to which grease can be applied, including lubricating points such as bearings, rolling bearings, sliding bearings, sliding surfaces, and gears. The grease composition of the present invention is most suitable for a site where there is a possibility of mixing rainwater, seawater, and the like. For example, it can be used for bicycles, fishing gear, and the like, in addition to automobiles, trucks, and industrial machines.

[0017]

Next, the present invention will be specifically described with reference to examples and comparative examples. However, the present invention is not limited by these examples. The evaluation in Examples and Comparative Examples of the present invention was performed by the following method. (1) Emulsification test An appropriate amount of grease is put in a transparent plastic container, and water is gently put on the grease layer so that the lower layer becomes a grease layer and the upper layer becomes an aqueous layer, and is heated at 30 ° C for 240 hours. The mixture was allowed to stand, the presence or absence of emulsification was visually observed, and evaluated according to the following criteria. ：: There is no cloudiness on the grease surface. (Pass) ×: There is cloudiness on the grease surface. (Fail) (2) Abrasion resistance test (evaluation of wear characteristics) The test was performed by the LFW-1 test. The test conditions were oil temperature 30
The friction coefficient after 5 minutes under a load of 650 N at 5 ° C. was measured and evaluated according to the following criteria. ：: The coefficient of friction is 0.10 or less. (Pass) ×: The coefficient of friction exceeds 0.10. (Fail) When the friction coefficient is reduced under these conditions, the wear resistance is improved. (The LFW-1 test is generally used as a friction and wear test for lubricating oil.) (3) Rust prevention test Prepare four JIS K2246 wet test specimens (# 240 polished), apply grease to both sides, and apply Three drops of salt water (5% by mass of sodium chloride) were dropped horizontally on the grease-coated surface of one of the two wet test pieces and the grease-coated surface of the wet test piece placed at the lower end of the two wet test pieces. In this state, four wet test pieces are stacked and laminated, and 50
After standing at 24 ° C. for 24 hours, the presence or absence of rust was visually observed and evaluated according to the following criteria. : There is no rust on the test piece. (Pass) ×: The test piece has rust. (Fail) (4) Adhesion test Two JIS K2246 wet test pieces (# 240 polished finish) were prepared, and the same as the rectangular test piece of the seal material test (JIS K6301) between the two wet test pieces. A volume of grease was applied, leveled and laminated. Next, a 1 kg weight is placed on the upper wet test piece, left at room temperature for 3 hours, and the upper part is pulled with a spring. The load at this time was defined as an adhesive load. ：: The adhesive load is 100 kg or more. (Pass) ×: The adhesive load is less than 100 kg. (failure)

(Production Example) Preparation of Grease Grease used in Examples and Comparative Examples of the present invention was prepared by the following method. Hydrogen-refined mineral oil (kinematic viscosity at 100 ° C .: 6 mm ² / s) is used as a base oil in a heat-resistant container, and 12-hydroxystearic acid is added as a thickener and heated. Next, an aqueous solution of lithium hydroxide is
C., and lithium-12-hydroxystearate is produced by a saponification reaction. This is further heated and dissolved, and quenched with base oil to obtain lithium-
The crystals of 12-hydroxystearate were optimized. Then, at about 90 ° C., various additives were added, mixed by stirring, dispersed, and degassed in vacuo to form lithium-12-.
A lithium grease in which hydroxystearate was uniformly mixed and dispersed in a base oil was prepared.

(Examples 1 to 5 and Comparative Examples 1 to 17) In Examples 1 to 5 and Comparative Examples 1 to 17, various additives shown in Tables 1 to 4 were added to the prepared grease. 60-8
After heating and stirring at 5 ° C. for about 2 hours to disperse the mixture, the mixture was defoamed. 2 grade (JIS K 222
0) was obtained. In addition, in Example 1 and each comparative example, calcium-12-hydroxystearate was used as a thickener, and calcium hydroxide was used instead of lithium hydroxide in the preparation of the grease. In Example 3, 8.0% by mass of cyclohexylamine and 10.0% by mass of diphenylmethane-4,4-diisocyanate were mixed with the base oil, and heated to 110 ° C. while stirring to synthesize diurea, And The units of the amounts of the various additives shown in Tables 1 to 4 are parts by mass. Table 1 shows the component compositions of the greases prepared in Examples 1 to 5 and the results of performance evaluation thereof,
Tables 2 to 4 show the component compositions of the greases prepared in Comparative Examples 1 to 17 and the results of performance evaluation.

[0020]

[Table 1] In Table 1, A represents 57.5 parts by mass of hydrogen refined oil and synthetic oil (P
AO) (kinematic viscosity at 100 ° C .: 6 mm ^{2 / s) is} 17.0 parts by mass.

[0021]

[Table 2]

[0022]

[Table 3]

[0023]

[Table 4]

The subscripts in the table indicate the following. * 1: MoDTP Molybdenum dithiophosphate in which R ¹ , R ² , R ³ and R ^{4 in the} formula (2) are an alkyl group having 8 carbon atoms * 2: Molybdenum dithiocarbamate R ¹⁰ , R ¹² , R ¹³ , R ¹⁴ is an octyl group,
Molybdenum dithiocarbamate which is a mixture of tridecyl groups

Embedded image

* 3: Molybdenum disulfide * 4: Acidic phosphate (C ₈ H ₁₇ O) ₂ P (O) OH * 5: Tricresyl phosphate * 6: Zinc naphthenate R ⁵ , R of formula (3) ⁶ is a mixture of an alkyl group having 8 to 16 carbon atoms; zinc naphthenate * 7: oxyethylene dodecylamine * 8: thiadiazole thiadiazo group in which R ⁷ and R ^{8 in} the formula (4) are alkyl groups having 8 carbon atoms * 9: Sorbitan monooleate * 10: Oleyl sarcosine * 11: Amino alcohol (dibutylethanolamine) * 12: Oxidized wax (partial ester B of oxidized wax)
a salt) a carboxyl group introduced by oxidizing paraffin wax, microlistarine wax, petrolatum, etc. obtained in the refinement of petroleum fraction * 13: Ca sulfonate Calcium sulfonate having a base number of 300 mg KOH / g (base number Is a value measured according to JIS-K-2501-6.)

* 14: Magnesium sulfonate Magnesium sulfonate having a base number of 300 mg KOH / g (The base number is a value measured according to JIS-K-2501-6.) * 15: Ba sulfonate Barium having a base number of 20 mg KOH / g Sulfonate (base number is a value measured according to JIS-K-2501-6) * 16: Alkenyl succinic acid derivative (manufactured by Lubrizol Co., trade name "859") * 17 and * 18: Dialkyldithiophosphoric acid Zinc (Primary type, Secondary type) As the primary type, those in which all alkyl groups are primary alkyl groups and have 8 carbon atoms were used. As the secondary type, an alkyl group having a secondary alkyl group and having 3 and 6 carbon atoms mixed in an equal amount was used. * 19: PIB1: polyisobutylene (number average molecular weight (Mn) = 50,000) * 20: PIB2: polyisobutylene (Mn = 80,0)
00) * 21: PIB3: polyisobutylene (Mn = 120,
* 22) DBPC: 2,6-di-tert-butylparacresol * 23: Commercial SP package (Lubrizol Corp., trade name "Anglamol 99A")

From the description in Tables 1 to 4, the thickener,
A grease composition combining a specific molybdenum dithiophosphate, a specific rust inhibitor and polyisobutylene,
It can be seen that the rust prevention and abrasion resistance are remarkably good.

[0028]

The grease composition of the present invention has excellent rust prevention and abrasion resistance. Therefore, the grease composition of the present invention is extremely useful in practical use.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C10M 135/36 C10M 135/36 137/10 137/10 A 143/06 143/06 // C10N 10:02 C10N 10:02 10:04 10:04 10:12 10:12 30:06 30:06 30:12 30:12 40:02 40:02 50:10 50:10 F term (reference) 4H104 BB17B BB26C BE04C BE13B BG19C BH07C CA04C DA02A EB02 EB06 FA01 FA02 FA06 LA03 LA06 PA01 QA18

Claims (3)

[Claims] (1) at least one base oil selected from a mineral lubricating base oil and a synthetic lubricating base oil, an antiwear agent comprising molybdenum dithiophosphate, a thickener, zinc naphthenate, thiadiazole and oxyethylene amine A grease composition comprising at least one selected rust inhibitor and polyisobutylene. 2. The grease composition according to claim 1, wherein the thickener is at least one selected from calcium grease, lithium grease, lithium complex grease and urea grease. 3. The grease composition according to claim 1, wherein the thickener is at least one selected from calcium grease and urea grease, and the rust inhibitor is zinc naphthenate.