JP2003013083A - Grease composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grease composition having excellent water-resistance and extreme-pressure lubricity. SOLUTION: The grease composition contains at least one kind of base oil selected from mineral oil lubricating base oil and synthetic lubricating base oil, 0.1-40 mass% one or more thickeners selected from calcium or lithium soap-based thickener, composite lithium soap-based thickener and urea-based thickener and 0.1-30 wt.% ultrafine calcium carbonate powder having an average particle diameter of 0.01-0.5 μm.

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 water resistance which can be applied to lubricated parts such as automobiles and industrial machines.

[0002]

2. Description of the Related Art Automobiles, trucks, industrial machines and the like are used in all environments. For example, automobiles and trucks are exposed to rainwater and seawater (saltwater) when traveling on the beach. Further, also in the industrial machine, there is a possibility that this water may enter in the part where the cooling water is used in the equipment process. When used in such an environment, there is a problem that water easily mixes with grease. Therefore, in the grease used in such places, even if water is mixed, the performance of suppressing the softening of the grease, that is, the so-called water resistance is further improved, and the performance such as the extreme pressure property of the grease is sufficiently improved. It is demanded that it can be demonstrated.

[0003]

An object of the present invention is to provide a grease composition having excellent water resistance and extreme pressure resistance. Further, it is an object of the present invention to provide a grease composition having excellent water resistance and extreme pressure, as well as excellent rust prevention and adhesion.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies in order to achieve the above object, and as a result, have found that a specific thickener and an average particle size of 0.01 to 0.5 μm are added to a base oil. It was found that the above problems can be solved by adding a specific amount of ultrafine calcium carbonate, and further by adding a specific amount of a specific rust inhibitor or a specific polyisobutylene to this composition, and the present invention is completed. Came to.

That is, the present invention relates to at least one base oil selected from mineral oil base oils and synthetic base oils, calcium or lithium soap base thickeners, and complex soap base thickeners thereof. And at least one thickener selected from urea-based thickeners in an amount of 0.1 to 4
The present invention provides a grease composition containing 0% by mass and 0.1 to 30% by mass of ultrafine calcium carbonate having an average particle size of 0.01 to 0.5 μm. Further, the present invention further comprises, in the grease composition, 0.1 to 3% by mass of zinc dithiophosphate, 0.05 to at least one rust preventive selected from zinc naphthenate, thiadiazole and oxyethylene alkylamine.
A grease composition containing 10 to 10 mass% is provided. The present invention also provides the above grease composition,
The present invention provides a grease composition containing 1 to 20% by mass of polyisobutylene having a number average molecular weight of 1,000 to 70,000. The present invention will be described in detail below.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The base oil used in the grease composition of the present invention includes mineral oil type lubricating base oils, synthetic type lubricating base oils, and mixed type oils thereof which are usually used for greases. Various lubricating base oils are used, but 40 ℃
The value of kinematic viscosity in is preferably 1 to 1000 mm ² / s, particularly preferably 1 to 500 mm ² / s. Examples of the mineral oil-based lubricating base oil include those obtained by refining a lubricating oil fraction of crude oil by appropriately combining solvent refining, hydrorefining, and the like.

Examples of synthetic lubricating base oils include α-olefin oligomers, which are polymers of α-olefins having 3 to 12 carbon atoms, 2-ethylhexyl sebacate, sebacates such as dioctyl sebacate, azelates, and the like.
Dialkyl diesters having 4 to 12 carbon atoms such as adipate, 1-trimethylolpropane, polyols including esters obtained from pentaerythritol and monobasic acid having 3 to 12 carbon atoms, alkyl group having 9 to 40 carbon atoms Alkyl benzenes having ## STR7 ##, 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. Examples thereof include ethers. The mineral base lubricating oil base oil and the synthetic base lubricating oil base oil may be used alone or in combination of two or more. The amount of the base oil can be appropriately selected according to the required characteristics, but is usually in the range of 60 to 95 mass% with respect to the grease consisting of the base oil and the thickener, and preferably 80 to
It is in the range of 90% by mass.

The thickener used in the grease composition of the present invention is at least one thickener selected from calcium or lithium soap thickeners, complex soap thickeners thereof and urea thickeners. It is a thickener. Examples of the calcium soap thickener include aliphatic carboxylic acid calcium salts having a hydroxyl group such as calcium-12-hydroxystearate.
As a lithium soap thickener, lithium-12
Examples thereof include a lithium salt of an aliphatic carboxylic acid having a hydroxyl group such as hydroxystearate, a lithium salt of an aliphatic carboxylic acid such as lithium stearate, or a mixture thereof. Examples of the complex lithium soap-based thickener include the above-mentioned complex of lithium salt of aliphatic carboxylic acid and lithium salt of dibasic acid. Examples of suitable dibasic acids include succinic acid, malonic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid and the like. Especially preferred are azelaic acid and sebacic acid. Examples of the urea thickener include reaction products of diisocyanate and amine. As the diisocyanate, diphenylmethane-4,4-diisocyanate is preferable. Examples of the amine include alicyclic amine, aromatic amine, and aliphatic amine. Examples of the alicyclic amine include cyclohexylamine and the like, examples of the aromatic amine include paratoluidine and benzylamine, and examples of the aliphatic amine include octylamine and laurylamine. These thickeners may be used alone or in combination of two or more. The content ratio of the thickener is 0.1 to 40% by mass, preferably 1 to 30% by mass, and particularly preferably 2 to 20% by mass, based on the grease composition.

The ultrafine calcium carbonate used in the grease composition of the present invention has an average particle size of 0.01.
To 0.5 μm, more preferably 0.01 to 0.3
μm, more preferably 0.01 to 0.2 μm, and particularly preferably 0.01 to 0.17 μm. If the average particle size is too large, the desired consistency cannot be obtained and the water resistance becomes insufficient. The content of ultrafine calcium carbonate is 0.1 to 30 mass% with respect to the grease composition, and preferably,
0.5 to 20% by mass, more preferably 1 to 15% by mass, and particularly preferably 2 to 12% by mass. If the amount of ultrafine calcium carbonate is too small, the water resistance will be insufficient, that is, the softening prevention property will be insufficient, and if it is too large, the grease will be too hard.

The grease composition of the present invention preferably contains zinc dithiophosphate. Examples of the zinc dithiophosphate include those represented by the general formula (1).

[Chemical 1] In the general formula (1), R ¹ , R ² , R ³ and R ⁴ are alkyl groups, preferably alkyl groups having 1 to 20 carbon atoms.
These may be the same or different. The alkyl group is preferably a primary alkyl group or a secondary alkyl group, and particularly preferably a primary alkyl group. 2-14 are preferable and, as for carbon number of an alkyl group, 3-10 are especially preferable.
Preferable alkyl groups include a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group and a decyl group. The said zinc dithiophosphate can be used individually by 1 type or in combination of 2 or more types. The content of zinc dithiophosphate is preferably 0.1 to 3% by mass, more preferably 0.1 to 2% by mass, still more preferably 0.2 to 1.5% by mass, and particularly It is preferably 0.5 to 1.2% by mass. If the content of zinc dithiophosphate is too small, the rust resistance will be poor, while if it is too large, the rust resistance will be poor.

Further, the grease composition of the present invention preferably contains at least one rust preventive selected from zinc naphthenate, thiadiazole and oxyethylene alkylamine. Zinc naphthenate is represented by the following formula (2).

[0012]

[Chemical 2] (In the formula, R ⁵ and R ⁶ are alkyl groups having 1 to 16 carbon atoms and 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 the carbon number thereof is preferably 1 to 16,
It is more preferably 3 to 16, and particularly preferably 8 to 16. Specific examples of the alkyl 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 group and the like. Can be mentioned. j and k are preferably 1 to 16, and particularly preferably 1 to 9. The zinc naphthenate may be used alone or in combination of two or more. 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. If the content of zinc naphthenate is too low, the rust preventive property becomes poor. On the other hand, if too much, the effect is saturated. Thiadiazole is represented by the following formula (3)
It is represented by.

[0013]

[Chemical 3] (In the formula, R ⁷ and R ⁸ are alkyl groups having 1 to 12 carbon atoms and may be the same or different.) In the above formula, the alkyl groups R ⁷ and R ⁸ are linear or branched. The number of carbon atoms is preferably 1 to 10,
Especially preferably, it is 1-8. Specific examples of the alkyl group include, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, isopentyl group, hexyl group, 2
Examples thereof include an ethylhexyl group and an octyl group. Specific preferred 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 the specifications of P2719125, 2719126 and the like. Thiadiazole may be used alone or in combination of two or more. The content ratio of thiadiazole is preferably 0.05 to 3.0% by mass, more preferably 0.1 to 2.
It is 0% by mass, more preferably 0.3 to 2.0% by mass, and particularly preferably 0.5 to 1.5% by mass. If the content of thiadiazole and its derivative is too small, the desired anticorrosive property cannot be obtained. On the other hand, if too much, the effect is saturated.
The oxyethylene amine is represented by the following formula (4).

[0014]

[Chemical 4] (In the formula, R ⁹ is a hydrocarbon group, and x and y are integers.) In the above formula, the hydrocarbon group represented by R ⁹ may be linear or branched, and the carbon number thereof is 8-18 are preferable, and 8
-16 are more preferable, and 8-12 are especially 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 0-5,
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 further preferably 0.3.
To 2.0% by mass, particularly preferably 0.5 to 1.5% by mass
Is. If the content of oxyethylene alkylamine is too small or too large, the rust preventive property will be deteriorated.

The grease composition of the present invention preferably contains polyisobutylene (hereinafter, also referred to as PIB) having a number average molecular weight of 1,000 to 70,000. The number average molecular weight of polyisobutylene is more preferably 1,000 to 55,000, and particularly preferably 100.
It is 0 to 35000. If the number average molecular weight is too small,
If the number average molecular weight is too large, the adhesion of grease may be deteriorated. The content ratio of polyisobutylene is preferably 1 to 20% by mass, more preferably 2 to 20% by mass,
More preferably 3 to 18% by mass, particularly preferably 3 to 1
It is 5% by mass. If the polyisobutylene content is too low, the adhesion of grease tends to deteriorate, and if the polyisobutylene content is too high, the effect is saturated.
The grease composition of the present invention can be prepared by mixing the above components.

The mixing order of the respective components is not particularly limited and may be appropriately added. However, the grease consisting of the base oil and the thickener is adjusted in advance in the 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 the precursor of the thickener is mixed and dispersed in the base oil, the precursor is reacted and the thickener is reacted. It is preferable to use a method in which an agent is formed and the thickener is dispersed in the base oil. The grease composition of the present invention may contain an antioxidant. Further, the grease composition of the present invention, within the range not impairing the object of the present invention,
Other additives can be blended. The grease composition of the present invention can be used in any lubrication location such as bearings, rolling bearings, sliding bearings, sliding surfaces, and gears, as well as any lubrication location to which grease can be applied. The grease composition of the present invention is most suitable for a site where rainwater, seawater, etc. may be mixed. For example, it can be used for automobiles, trucks, industrial machines and the like.

[0017]

EXAMPLES Next, the present invention will be specifically described with reference to Examples and Comparative Examples. However, the present invention is not limited to these examples. The evaluations in Examples and Comparative Examples of the present invention were performed by the following methods. <Evaluation Method> (1) A water resistant shell roll test (ASTM D 1831) was performed. The test conditions are 50 g of grease and 50 of ion-exchanged water.
g in a test container, test temperature 80 ℃, rotation speed 165r
pm, test time 5 h. The evaluation was performed by the rate of change in consistency before and after the test, and the results were within ± 10%. (2) An extreme pressure shell four-ball test (based on ASTM D 2596) was performed. The test was carried out by mixing 25% by mass of ion-exchanged water with grease, and using this, at a rotation speed of 1800 rpm, oil temperature; duration, time: 10 seconds, load; step load. The evaluation was performed with a fusion load, and 2450 N or more was regarded as acceptable. (3) Anti-rust property (rust prevention test) Prepare four JIS K2246 wet test pieces (# 240 polished finish), apply grease to both sides, and sandwich the two wet test pieces sandwiched in the middle with the grease application surface on one side and On the grease application surface of the wet test piece placed at the lower end, 3 drops of salt water (sodium chloride 5% by mass) were dropped in a horizontal state, and in this state, 4 wet test pieces were stacked and laminated, 5
After leaving at 0 ° C for 24 hours, visually inspect for rust,
It evaluated by the following criteria. ◯: There is no rust on the test piece. (Pass) x: The test piece has rust. (Failure) (4) Adhesion (Adhesion test) Two pieces of JIS K2246 wet test pieces (# 240 polished finish) are prepared, and a rectangular seal material test (JIS K6301) is provided between the two wet test pieces. The same volume of grease as the test piece was applied and laminated horizontally. Next, place a 1 kg weight on the upper wet test piece and leave it for 3 hours at room temperature.
Pull the top with only a spring. The load at this time was defined as the adhesive load. ◯: Adhesive load is 50 kg or more. (Pass) x: The adhesive load is less than 50 kg. (failure)

Preparation of Grease The grease used in the examples and comparative examples of the present invention was prepared by the following production examples. (Production Example 1) Hydrorefined mineral oil (1
A kinematic viscosity at 00 ° C .: 6 mm ² / s) is used, 12-hydroxystearate is added as a thickener, and the mixture is heated. Next, an aqueous lithium hydroxide solution is added at about 70 ° C. to produce lithium-12-hydroxystearate by a saponification reaction. Further, this was heated, dissolved, and quenched with base oil to optimize the crystals of lithium-12-hydroxystearate, and lithium-12-hydroxystearate was uniformly mixed and dispersed in the base oil. A lithium grease was prepared. (Production Example 2) A as a base oil and 12-hydroxystearate as a thickener are put into a heat-resistant container and heated. Next, a lithium hydroxide aqueous solution is added at about 80 ° C. to generate lithium-12-hydroxystearate by a saponification reaction. Further, lithium hydroxide and azelaic acid are added at about 90 ° C. and reacted for about 2 hours to form lithium complex soap. After that, this is heated, semi-molten and then rapidly cooled to optimize the crystals of the lithium complex soap, and the lithium complex soap of lithium-12-hydroxystearate / azelaic acid lithium salt is added to the base oil. A lithium grease that was uniformly mixed and dispersed was prepared.

(Examples 1 to 14 and Comparative Examples 1 to 4) Examples 1 to 4, 8 to 14 and Comparative Examples 1 to 3 are shown in Tables 1 to 3 in the lithium grease prepared in Production Example 1. Add various additives and heat and stir at 60 to 85 ° C for about 2 hours,
After dispersing, degassing is performed and the consistency is No. 1. A two-grade (JISK 2220) grease composition was obtained. In Example 5, calcium-1 was used as a thickener.
2-hydroxystearate was used and calcium hydroxide was used in place of lithium hydroxide in the preparation of the grease. Further, in Example 6, in the preparation of the grease, cyclohexylamine 8.0 was added to the base oil.
Mass% and 10.0 mass% of diphenylmethane-4,4-diisocyanate were mixed and heated to 110 ° C. with stirring to synthesize diurea represented by the following formula (5) to obtain a grease. Further, in Example 7, the lithium grease prepared in Production Example 2 was used instead of the lithium grease prepared in Production Example 1.

[Chemical 5] The units for the amounts of various additives shown in Tables 1 to 3 are parts by mass. Tables 1 and 2 show the component compositions of the greases prepared in Examples 1 to 14 and the results of their performance evaluations, and Table 3 shows the component compositions of the greases prepared in Comparative Examples 1 to 4 and their performance evaluations. The results are shown below.

[0020]

[Table 1]

[0021]

[Table 2]

[0022]

[Table 3]

In Table 1, A is 57.5 parts by mass of hydrogen refined oil and synthetic oil (PAO) (kinematic viscosity at 100 ° C .: 6 mm ² /
s) 17.0 parts by mass of mixture. In addition, Table 1 to Table 3
The subscripts are shown below. * 1. Calcium carbonate with an average particle size of 0.04 μm * 2. Calcium carbonate with an average particle size of 0.15 μm * 3. Zinc dithiophosphate (primary type with alkyl group C = 8) * 4. Zinc naphthenate Zinc naphthenate wherein R ⁵ and R ⁶ of the formula (2) are a mixture of alkyl groups having 8 to 16 carbon atoms * 5. Oxyethylene dodecylamine formula (4) R ⁹ has 12 carbon atoms, x is 0, and y
Is 1 oxyethylene dodecylamine * 6. Thiadiazole Thiadiazole * 7, wherein R ⁷ and R ⁸ of the formula (3) are alkyl groups having 8 carbon atoms. Calcium carbonate having an average particle size of 2.00 μm * 8. Calcium oxide * 9. Sorbitan monooleate * 10. Oleyl sarcosine * 11. Amino alcohol (dibutyl ethanolamine) * 12. Oxidized wax (partial ester B of oxidized wax B
a salt) Introducing a carboxyl group by oxidizing paraffin wax, microlisterin wax, petrolatum and the like obtained during the purification of petroleum fraction * 13. Calcium sulfonate with a Ca sulfonate base number of 300 mg KOH / g was used. The base number is a value measured according to JIS-K-2501-6. * 14. Ba sulphonate Barium sulphonate with a base number of 20 mg KOH / g was used. The base number is a value measured according to JIS-K-2501-6. * 15. Alkenyl succinimide Bis-type polyalkenyl succinimide having a butenyl group molecular weight of about 2000 was used.

From the descriptions in Tables 1 to 3 above, the grease composition containing the specific thickener and the specific ultrafine calcium carbonate is excellent in water resistance and extreme pressure. It can be seen that the grease composition in which a specific rust preventive agent and polyisobutylene are combined has excellent rust preventive properties and adhesion properties as well as water resistance and extreme pressure properties.

[0025]

The grease composition of the present invention has excellent water resistance and extreme pressure resistance. Therefore, the grease composition of the present invention is extremely useful in practice.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C10M 125/10 C10M 125/10 129/58 129/58 133/08 133/08 135/36 135/36 137 / 10 137/10 A 143/06 143/06 149/14 149/14 // C10N 10:02 C10N 10:02 10:04 10:04 20:04 20:04 20:06 20:06 Z 30:00 30:00 C 30:06 30:06 30:12 30:12 40:02 40:02 40:04 40:04 50:10 50:10 F-term (reference) 4H104 AA13C BB17B BB18B BB19B BB26C BE04C BE13B BG19C BH07C CA04C CE19C DA02A EA03C EA08C EB02 FA01 FA02 LA03 LA06 LA13 PA01 PA02 QA18

Claims (3)

[Claims] 1. At least one base oil selected from mineral oil base oils and synthetic base oils, calcium or lithium soap base thickeners, complex lithium soap base thickeners and urea base thickeners. 0.1 to 40 mass% of at least one thickener selected from the agents, and ultrafine calcium carbonate having an average particle diameter of 0.01 to 0.5 μm are added in an amount of 0.1.
A grease composition containing 1 to 30% by mass. 2. A zinc dithiophosphate is further added to the.
1 to 3% by mass, 0.05 to 10% by mass of at least one rust preventive selected from zinc naphthenate, thiadiazole and oxyethylene alkylamine.
The grease composition described. 3. A number average molecular weight of 1,000 to 7,000.
The grease composition according to claim 1 or 2, containing 0 to 20% by mass of polyisobutylene.