JP5967138B2 - Grease composition and machine parts - Google Patents

Description

  The present invention relates to a grease composition, and more particularly to a grease composition excellent in rust prevention and a machine part using the grease composition, and particularly a bearing.

Represented in rolling bearing parts, compressors, blowers, etc. where rust due to intrusion of water, salt water, sea water, etc. on the road during driving, such as automobile electrical parts, engine auxiliary equipment, etc. represented by alternators and electromagnetic clutches, etc. Typical examples include rolling bearing parts, washing machine and refrigerator, bathroom ventilators and bathroom dryers seen in recent years. There are a variety of mechanical parts where rust is a problem, such as rolling bearing parts where rust due to a high humidity environment is a problem, such as motors for home appliances.
Such rolling bearings in which the occurrence of rust is a problem is prevented from being mixed with substances that cause rust by appropriate sealing and mechanical measures.
For example, in an automobile, measures are taken such as arranging it at a position where it is not directly exposed to muddy water or attaching mudguards or the like.
However, since the rolling bearing cannot be completely sealed due to its mechanism, the lubricating grease to be used must also have rust prevention performance.

For example, Patent Document 1 discloses a grease composition containing an oil-soluble organic inhibitor, a water-soluble inorganic passivating agent, and a nonionic surfactant as a rust inhibitor.
Patent Document 2 discloses a grease composition for encapsulating a bearing in which barium sulfonate is blended as a rust inhibitor.
However, it is known as a water-soluble inorganic passivating agent, and sodium nitrite, which has been widely used, is known to react with secondary amines to produce carcinogen N-nitrosamines, There are concerns about adverse effects on the human body.
Further, the antirust property of only organic sulfonates such as barium sulfonate widely used as an oil-soluble organic inhibitor is unsatisfactory particularly under severe conditions such as salt water conditions and sea water conditions.
In addition, as described in Non-Patent Document 1, barium sulfonate has a voluntary regulation in the industry as an environmental load substance.

Patent 2883134 Japanese Patent Laid-Open No. 5-140576

NTN TECHNICAL REVIEW No.73 (2005) P10-13

An object of the present invention is to provide a grease composition that is excellent in rust prevention properties and has a low environmental load.
Another object of the present invention is to provide a machine part, particularly a bearing, using the above grease composition.

The present invention provides the following grease composition and machine parts using the same.
1. A grease composition comprising a base oil, a thickener, and a rust inhibitor, wherein the rust inhibitor comprises an organic sulfonate and a fatty acid amine salt.
2. 2. The grease composition as described in 1 above, wherein the organic sulfonate is at least one selected from the group consisting of calcium sulfonate and zinc sulfonate.
3. 3. The grease composition according to 1 or 2 above, wherein the fatty acid amine salt is a salt of an amine and a fatty acid having 4 to 22 carbon atoms.
4). 4. The grease composition according to any one of items 1 to 3, which is for a rolling bearing.
5. A machine part using the grease composition according to any one of 1 to 4 above.

  The grease composition of the present invention has excellent rust prevention properties even under severe rust generation conditions.

The thickener used in the grease composition of the present invention is not particularly limited. For example, metal soaps containing lithium, sodium, and the like, benton, silica gel, urea compounds, non-soaps such as fluorine-based thickeners typified by polytetrafluoroethylene, and the like can be given. Particularly preferred are urea compounds and lithium soaps. These are practical thickeners because they have few drawbacks and are not expensive.
One type of thickener may be used alone, or two or more types may be used in combination.
The consistency of the grease composition of the present invention is preferably 200 to 400, and the content of the thickener is an amount necessary to obtain this consistency. Usually, it is preferably 3 to 30% by mass, more preferably 5 to 30% by mass, and most preferably 8 to 25% by mass with respect to the entire grease composition.

The base oil used in the grease composition of the present invention is a synthetic oil selected from the group consisting of ester synthetic oils and synthetic hydrocarbon oils. Examples thereof include ester-based synthetic oils typified by diesters and polyol esters; synthetic hydrocarbon oils typified by polyalphaolefins and polybutenes.
One type of base oil may be used alone, or two or more types may be used in combination.

The rust inhibitor used in the present invention contains an organic sulfonate and a fatty acid amine salt as essential components.
Examples of the sulfonic acid component of the sulfonate include petroleum sulfonic acid, dinonylnaphthalene sulfonic acid and the like, and the salt is preferably a metal salt, and in particular, calcium salt, magnesium salt, sodium salt, potassium salt, lithium Examples include salts and zinc salts. Particularly preferred salts are calcium salts or zinc salts.
In the grease composition of the present invention, the organic sulfonate may be used alone or in combination of two or more.
In the grease composition of the present invention, the content of the organic sulfonate is preferably 0.1 to 10% by mass, more preferably 0.1 to 8% by mass, and still more preferably 0.2% as an active ingredient. ˜5 mass%.

The fatty acid constituting the fatty acid amine salt is preferably a fatty acid having 4 to 22 carbon atoms, more preferably a fatty acid having 8 to 18 carbon atoms. The fatty acid may be a saturated fatty acid or an unsaturated fatty acid, and may be a linear fatty acid, a branched fatty acid, a cyclic fatty acid, or a hydroxy fatty acid. Specific examples include stearic acid, palmitic acid, myristic acid, lauric acid, isostearic acid, octylic acid, undecylenic acid, oleic acid, and hydroxystearic acid.
The amine constituting the fatty acid amine salt is not particularly limited, but is preferably a saturated or unsaturated amine having 1 to 42 carbon atoms, more preferably a saturated or unsaturated amine having 4 to 22 carbon atoms. .
Specifically, octylamine, laurylamine, myristylamine, stearylamine, behenylamine, oleylamine, beef tallow alkylamine, hardened tallow alkylamine, aniline, benzylamine, cyclohexylamine, diethylamine, dipropylamine, dibutylamine, diphenylamine, Examples include dibenzylamine, dicyclohexylamine, triethylamine, tributylamine, dimethyloctylamine, dimethyldecylamine, dimethylstearylamine, dimethyl beef tallow alkylamine, dimethyl-cured tallow alkylamine, and dimethyloleylamine.

In the grease composition of the present invention, the fatty acid amine salt may be used alone or in combination of two or more.
In the grease composition of the present invention, the content of the fatty acid amine salt is preferably 0.05 to 5% by mass, more preferably 0.05 to 3% by mass, and still more preferably 0.1 to 0.1% as an active ingredient. 2% by mass.

  In the grease composition of the present invention, in addition to the organic sulfonate and fatty acid amine salt, all additives usually used in the grease composition may be used alone or in combination of two or more as required. I can do it. Examples of these additives include antioxidants, metal deactivators, detergent dispersants, extreme pressure additives, defoamers, demulsifiers, oiliness improvers, antiwear agents, solid lubricants, and the like. .

Example Using the following components, a predetermined amount of an additive was added to the base grease and mixed well, and the mixture was kneaded with a three-roll mill to produce grease compositions shown in Tables 1 and 2.
Base grease:
A. Thickener: lithium 12-hydroxystearate
Base oil: Polyol ester 40 ° C. Kinematic viscosity 34.0 mm ² / s
Consistency: 250
B. Thickener: Diurea compound (reaction product of p-toluidine (2 mol) and diphenylmethane diisocyanate (1 mol))
Base oil: Poly α-olefin 40 ° C. Kinematic viscosity 48.0 mm ² / s
Consistency: 280
Rust inhibitor:
C. Calcium sulfonate (calcium dinonylnaphthalene sulfonate)
D. Zinc sulfonate (zinc dinonylnaphthalene sulfonate)
E. Fatty acid amine salt (a mixture of a fatty acid having 8 carbon atoms and an amine having 12 carbon atoms, and a mixture of two salts of a fatty acid having 18 carbon atoms and 12 to 20 carbon atoms (mixed) (mass ratio 2: 1) )

<Test method>
・ Rust prevention: Emcor rust prevention test (IP220) Artificial seawater use (ISO7120)
・ Judgment method: Observation of rusting state on outer ring transfer surface (n = 2)
Passed 0: No rusting Fail 1: Less than 3 small spot rusts
2: Rust area within 1%
3: Over 1% to 5% rust area
4: Rust area over 5% and within 10%
5: Over 10%

In Examples 1 to 6, in which organic sulfonates (rust inhibitors C and D) and fatty acid amine salts (rust inhibitors E) were combined and blended, no rusting occurred, and the rust prevention properties were good.
Comparative Examples 1 (compounding with rust inhibitor C), Comparative Example 2 (comprising rust inhibitor D), Comparative Example 3 (comprising rust inhibitors C and D), Comparative Example 4 (rust inhibitor) Rust generation was observed in all of the agents E), and the antirust property was inferior.
Rust generation was observed in Comparative Example 5 (compounding with rust inhibitors C and D), which was blended in the same amount as Example 6 and the rust inhibitor, and the rust preventive properties were inferior.
As is clear from the above examples, the grease composition of the present invention uses an organic sulfonate salt and a fatty acid amine salt in combination, and therefore has excellent rust preventive properties even under severe rusting conditions. It has been shown.

Claims (5)

A grease composition comprising a base oil, a thickener, and a rust inhibitor, wherein the base oil is a synthetic oil selected from the group consisting of ester synthetic oils and synthetic hydrocarbon oils, and the thickener is 12- A grease composition, wherein the grease composition is lithium hydroxystearate, and the rust inhibitor contains an organic sulfonate and a fatty acid amine salt.   The grease composition according to claim 1, wherein the organic sulfonate is at least one selected from the group consisting of calcium sulfonate and zinc sulfonate.   The grease composition according to claim 1 or 2, wherein the fatty acid amine salt is a salt of an amine and a fatty acid having 4 to 22 carbon atoms.   The grease composition according to any one of claims 1 to 3, which is used for a rolling bearing.   A machine part using the grease composition according to any one of claims 1 to 4.