JP2000129279A - Lubricating oil composition for chain - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lubricating oil composition which has a high heat resistance, a low tar content and a good property as a lubricating oil for chains, i.e., an inhibitory effect on decrease in the lubricating property caused by oil shortage. SOLUTION: Based on the total weight of a lubricating oil composition, from 0.1 to 5 wt.% one or more amine antioxidants and from 0.01 to 20 wt.% solid lubricant are dispersed in a base oil containing an aromatic carboxylic ester obtained by completely esterifying one or more aromatic carboxylic acids and a monohydric alcohol which contains 50 mol% or more 3,5,5- trimethylhexanol and has a 4-18C straight-chained or branched alkyl group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating oil composition having excellent heat resistance and stability, and more particularly, to a solid lubricant-dispersed aromatic ester suitable for use as a lubricating oil for chains of various mechanical devices. The present invention relates to a lubricating oil composition for a system chain.

[0002]

2. Description of the Related Art In recent years, with high speed, high load, high efficiency, energy saving, maintenance free, low cost, etc. of machinery, heat resistance to lubricating oil is high, and long life is achieved. There is a demand for a performance that has a wide use temperature range and a small amount of tar even when deteriorated, which is advantageous for maintenance. Therefore, synthetic oil-based lubricating oils having good performance have been used in place of conventional mineral oil-based lubricating oils.

[0003] Synthetic oils include synthetic hydrocarbons such as poly-α-olefins, polybutenes, alkylbenzenes, and alkylnaphthalenes, organic acid esters (hereinafter abbreviated as “esters”), phosphate esters, polyalkylene glycols, polyphenyl ethers, alkyl There are phenyl ether, silicone oil, etc., especially esters have longer life (good heat resistance), wide operating temperature range (low pour point, high viscosity index) and good lubricity compared to mineral oil base oils. It has advantages such as low volatility. At present, the main stream of ester base oils is polyol ester, jet engine oil,
It has come to be used favorably in the fields of gas turbine oil, compressor oil, chain oil, hydraulic oil, gear oil, bearing oil, grease base oil and the like.

[0004] However, the use conditions are becoming more severe, and the polyol ester has an increased acid value due to deterioration at a high temperature and has a tar content (sludge, varnish, coke).
This has become a problem in terms of heat resistance, such as the formation of heat. For example, lubricating oil for a chain is used under a high temperature condition of 230 to 250 ° C. Under such circumstances, even if a polyol ester-based lubricating oil is used, tar components are generated due to the oxidative deterioration of the oil, which imposes a heavy burden on maintenance, such as cleaning work, and work due to the generation of odor. Oil is likely to run out due to deterioration of the environment and evaporation loss of the oil due to volatilization, so the frequency of refueling is increased and the effect on cost is increased. Further, from the viewpoint of lubricity, running out of oil causes squeak noise of the chain and wear progresses, which affects the life of the apparatus.

On the other hand, recently, aromatic carboxylic acid esters containing 3,5,5-trimethylhexanol as an alcohol component have excellent chemical properties (heat resistance, low tar property) and physical properties as a lubricating base oil. It is reported that the properties (viscosity index, pour point) are also excellent (Japanese Patent Laid-Open No. 10-130).
No. 673). However, when used as a lubricating oil for chains, since the lubricant is usually used in an open system, there is still room for improvement in terms of volatility.

[0006]

DISCLOSURE OF THE INVENTION The present invention is to provide a conventional aromatic carboxylic acid 3,5,5-trimethylhexyl ester lubricating oil while maintaining its chemical properties (heat resistance and low tar resistance). It is still another object of the present invention to provide a lubricating oil composition having good properties as a lubricating oil for chains, that is, effective in suppressing a decrease in lubricity due to oil shortage.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, have found that aromatic carboxylic acid 3,3
When a lubricating oil composition in which an amine antioxidant is blended with a 5,5-trimethylhexyl ester base oil and fine powder of a solid lubricant is further dispersed is used as a lubricating oil for a chain, a conventional fragrance is used. It has been found that they have a remarkably superior effect as compared with aromatic carboxylic acid esters. Furthermore, when a specific solid lubricant is used, it has been found that more excellent lubrication performance can be obtained by using a dispersant and / or a dispersion stabilizer in combination, and the present invention has been completed based on such findings.

That is, the lubricating oil composition for chains according to the present invention comprises one or more aromatic carboxylic acids,
Aromatic carboxylic acid esters obtained by completely esterifying a monohydric alcohol having a linear or branched alkyl group having 4 to 18 carbon atoms and containing at least 50 mol% of 5,5-trimethylhexanol (hereinafter referred to as an aromatic carboxylic acid ester) , "The present ester"), one or more amine antioxidants in an amount of 0.1 to 2 parts by weight based on the total weight of the lubricating oil composition.
5% by weight and 0.01 to 20% by weight of a solid lubricant are dispersed.

[0009]

DETAILED DESCRIPTION OF THE INVENTION The aromatic carboxylic acids used in the present invention include phthalic acid, 4-t-butylphthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, trimesic acid, pyromellitic acid, naphthalenedicarboxylic acid, biphenyl Aromatic carboxylic acids such as dicarboxylic acid, 4,4'-oxybisbenzoic acid and 4,4'-thiobisbenzoic acid or anhydrides thereof, and aromatic carboxylic acids and lower alcohols having 1 to 4 carbon atoms such as methanol and ethanol Esters are exemplified.

Among these aromatic carboxylic acids, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, trimesic acid and pyromellitic acid are particularly recommended, and are used under extremely severe high-temperature conditions as chain lubricating oils. It is preferable to use trimellitic acid, trimesic acid or pyromellitic acid which provides an ester having a high viscosity and a small evaporation loss.

The monohydric alcohol constituting the present ester is an aliphatic monohydric alcohol having a linear or branched alkyl group having 4 to 18 carbon atoms (provided that 3,5,5
Contains at least 50 mol% of 5-trimethylhexanol. More specifically, in addition to 3,5,5-trimethylhexanol, n-butyl alcohol, isobutyl alcohol, n-amyl alcohol, isoamyl alcohol, n-hexanol, isohexanol, n-heptanol, isoheptanol Nol, n-octanol, isooctanol, 2-ethylhexanol, n-nonanol, isononanol, n-decanol, isodecanol, n-undecanol, isoundecanol, n-dodecanol, isododecanol, n-tridecanol,
Isotridecanol, n-tetradecanol, isotetradecanol, n-pentadecanol, isopentadecanol, n-hexadecanol, isohexadecanol, n-octadecanol, isooctadecanol, etc. Is exemplified. It is also possible to use lower alkyl esters such as acetates of these alcohols instead of these alcohols.

The monohydric alcohol constituting the present ester is
Although 3,5,5-trimethylhexanol is contained in an amount of 50 mol% or more, the content is preferably 70 mol% or more, and more preferably 3,5,5-trimethylhexanol alone. If the amount is less than 50 mol%, the heat resistance tends to decrease and the tendency to generate tar is recognized.

On the other hand, a lubricating oil having a higher viscosity index may be required for some applications. In this case, it is preferable to use a linear or branched aliphatic monohydric alcohol having 4 to 18 carbon atoms as the monohydric alcohol,
Among them, a linear monohydric alcohol having 8 to 14 carbon atoms is particularly recommended.

Preferred esters for use in the present invention include di (3,5,5-trimethylhexyl) phthalate,
Di (3,5,5-trimethylhexyl) isophthalate,
Tri (3,5,5-trimethylhexyl) trimellitate, tri (3,5,5-trimethylhexyl) trimesate and tetra (3,5,5-trimethylhexyl) pyromellitate are exemplified, and among these, Tri (3,5,5-trimethylhexyl) trimellitate, tri (3,5,5-trimethylhexyl) trimesate and tetra (3,5,5-trimethylhexyl) pyromellitate are recommended.

As the amine-based antioxidant used in the present invention, one or two selected from the group of compounds represented by the following general formulas (1), (2) and (3): Species or more.

[0016] [Wherein, R ¹ , R ² , R ³ and R ⁴ are the same or different and each represent a hydrogen atom or a linear or branched alkyl group having 1 to 18 carbon atoms. ]

[0017] [In the formula, R ⁵ , R ⁶ , R ⁷ and R ⁸ are the same or different and each represent a hydrogen atom or a linear or branched alkyl group having 1 to 18 carbon atoms. ]

[0018] [Wherein R ⁹ , R ¹⁰ and R ¹¹ are the same or different,
Represents a hydrogen atom or a linear or branched alkyl group having 1 to 18 carbon atoms. ]

Specific examples of the amine-based antioxidant represented by the general formula (1) include N-phenyl-α-naphthylamine, N-butylphenyl-α-naphthylamine, N-pentylphenyl-α-naphthylamine, -Hexylphenyl-α-naphthylamine, N-heptylphenyl-
α-naphthylamine, N-octylphenyl-α-naphthylamine, N-nonylphenyl-α-naphthylamine and the like. Of these, N-phenyl-α-naphthylamine and N-octylphenyl-α-naphthylamine are particularly preferred.

Specific examples of the amine antioxidant represented by the general formula (2) include diphenylamine, p, p'-dibutyldiphenylamine, p, p'-dipentyldiphenylamine, p, p'-dihexyldiphenylamine,
In addition to p, p'-diheptyldiphenylamine, p, p'-dioctyldiphenylamine, p, p'-dinonyldiphenylamine, a mixed alkyldiphenylamine having 4 to 9 carbon atoms and the like can be mentioned. Of these, p, p'-dioctyldiphenylamine is particularly preferred.

Specific examples of the amine antioxidant represented by the general formula (3) include p-phenylenediamine, N-phenyl-N'-isopropyl-p-phenylenediamine, N-phenyl-N '-( 1,3-dimethylbutyl)
-P-phenylenediamine and the like.

The amine type antioxidant represented by the above general formula (1), general formula (2) or general formula (3) is used in an amount of 0.1 to 5% by weight based on the total weight of the lubricating oil composition. Preferably 0.
3 to 3% by weight is blended. If the amount added is less than 0.1% by weight, the antioxidant properties are poor, and if it exceeds 5% by weight, no significant improvement in the antioxidant properties is observed.

Further, the lubricating oil composition for a chain according to the present invention is characterized in that a solid lubricant is dispersed therein.
As the solid dispersant, a compound that is effective in reducing wear at the time of running out of oil at a high temperature, preventing seizure, and reducing squeak noise is selected. Specifically, boron nitride, molybdenum disulfide, graphite, polytetrafluoroethylene (PTF
E), carbon fluoride, cerium fluoride, antimony sulfide,
Examples thereof include borates of alkali metals and alkaline earth metals, and among them, boron nitride or molybdenum disulfide is recommended.

Since molybdenum disulfide is black,
Depending on the type of business, products may be colored due to scattering of lubricant,
Also, the workplace may be contaminated. In this case, it is particularly preferable to use boron nitride which is white, has good dispersibility, and further has excellent lubrication performance at high temperatures. As for boron nitride, those belonging to various crystal systems such as cubic, rhombohedral, hexagonal, etc. are known. However, in the present invention, hexagonal or rhombohedral nitride having cracking property, that is, slipping performance is known. A layered structure such as boron is used.

The solid lubricant to be dispersed is preferably in the form of fine powder. The finer the powder, the better the dispersibility.
Those having a diameter of from 01 to 10 μm, preferably from 0.05 to 5 μm are exemplified.

The amount of the solid dispersant to be used is 0.01 to 20% by weight, preferably 0.05 to 5% by weight, based on the total weight of the lubricating oil composition. If the amount is less than 0.01% by weight, the effect of the addition is not sufficient,
Even if added in an amount exceeding 20% by weight, no significant improvement in the friction reducing effect is observed.

The method of dispersing the solid dispersant in the lubricating oil includes, for example, a method of dispersing the solid dispersant by high-speed stirring with a homogenizer or the like, but is not particularly limited, and includes a tube mill, a media mill, a static mixer, and a super mixer. Conventionally known materials such as acoustic dispersion may be used. or,
When the solid lubricant is dispersed, a dispersant and / or a dispersion stabilizer can be used for the purpose of improving dispersibility and dispersion stability.

Specific dispersants include succinimides having an alkyl or alkenyl substituent, succinamides having an alkyl or alkenyl substituent, benzylamine having an alkyl or alkenyl substituent, and alkyl or alkenyl substituents. Ashless dispersants such as succinates and derivatives obtained by treating these with a boron compound are exemplified. Examples of the dispersion stabilizer include fatty acid amides having 12 to 22 carbon atoms, ethylene propylene copolymer, polyethylene oxide, and the like.
5% by weight, preferably 0.1 to 3% by weight.

In particular, when boron nitride is used as the solid dispersant, it is very effective to disperse the solid dispersant using a dispersant and / or a dispersion stabilizer.

Among the above dispersants and / or dispersion stabilizers, succinimide having an alkyl or alkenyl substituent, benzylamine having an alkyl or alkenyl substituent, stearylamide, polyethylene oxide, and the like are preferred. One or more of these can be used in combination.

An aromatic carboxylic acid ester according to the present invention,
More preferred combinations among amine-based antioxidants, solid lubricants, dispersants and / or dispersion stabilizers are as follows: tri (3,5,5-trimethylhexyl) trimellitate, N-phenyl-α-naphthylamine And trinitrate trimellitate (3,5,5-trimethylhexyl), p, p'-dioctyldiphenylamine and boron nitride, tritrimesate (3,5,5-trimethylhexyl), N- Phenyl-α-naphthylamine and boron nitride; tri (3,5,5-trimethylhexyl) trimesate, p, p′-dioctyldiphenylamine and boron nitride; tetrapyrimellitate (to 3,5,5-trimethyl) Xyl), N-phenyl-α-naphthylamine and boron nitride, tetrapyromellitic acid tetra (3,5,5-trime Hexyl), p, p'-dioctyldiphenylamine and boron nitride, tetra (3,5,5-trimethylhexyl) pyromellitate, N-phenyl-α-naphthylamine and boron nitride, 3,5,5-trimethylhexyl), N-phenyl-α-naphthylamine, boron nitride and benzylamine-based dispersant Tritrimellitic acid (3,5,5-trimethylhexyl), p, p′-dioctyl Diphenylamine, boron nitride and benzylamine dispersants; tri (3,5,5-trimethylhexyl) trimesate, N-phenyl-α-naphthylamine, boron nitride and benzylamine dispersants; 5,5-trimethylhexyl), p, p'-dioctyldiphenylamine, boron nitride and benzyl Min-based dispersants, Tetra pyromellitic acid (3,5,5-trimethylhexyl), N-phenyl-α-naphthylamine, boron nitride and benzylamine-based dispersants, Tetra pyromellitic acid (3,5,5) -Trimethylhexyl), p, p'-dioctyldiphenylamine, boron nitride and benzylamine dispersants.

Further, the lubricating oil composition according to the present invention can improve the abrasion resistance by incorporating a phosphate ester as an anti-wear agent, and can greatly improve the performance of the lubricating oil.

The phosphate used in the present invention includes:
One or more selected from phosphoric acid triesters represented by the general formula (4) are used.

[0034] [Wherein, R ¹² , R ¹³ and R ¹⁴ are the same or different and are each a linear or branched alkyl group having 3 to 18 carbon atoms, or a linear or branched alkyl group having 3 to 18 carbon atoms. Represents an alkenyl group or an aryl group which may have an alkyl substituent. ]

Specific examples of the phosphate represented by the general formula (4) include tributyl phosphate, triisopropyl phosphate, trioctyl phosphate, tri (2-ethylhexyl) phosphate, trilauryl phosphate, and tritriphosphate. Stearyl, trialkyl phosphate such as trioleyl phosphate, phenyl dibutyl phosphate, phenyl diisopropyl phosphate, phenyl dioctyl phosphate, phenyl di (2-ethylhexyl) phosphate, phenyl dilauryl phosphate,
Phenyldistearyl phosphate, phenyldioleyl phosphate, diphenylbutyl phosphate, diphenylisoproppropyl phosphate, diphenyloctyl phosphate, diphenyl-2-ethylhexyl phosphate, diphenyllauryl phosphate, diphenylstearyl phosphate, diphenyloleyl phosphate Alkyl-aryl phosphate mixed ester such as triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, phenyl dicresyl phosphate, phenyl dixylenyl phosphate, diphenyl cresyl phosphate, diphenyl xylenyl phosphate, Examples include triaryl phosphate esters such as phenyl-di (propylphenyl) phosphate, diphenyl-propylphenyl phosphate, and tri (propylphenyl) phosphate. Of these, tributyl phosphate, trioctyl phosphate and tricresyl phosphate are preferred.

The phosphates represented by the above general formula (4) are blended in an amount of 0.1 to 10% by weight, preferably 0.5 to 7% by weight, based on the total weight of the lubricating oil composition. If the amount is less than 0.1% by weight, the wear resistance is poor, and if it exceeds 10% by weight, no significant improvement in the wear resistance is observed.

On the other hand, the lubricating oil composition for a chain according to the present invention may be used in addition to the present ester, as well as mineral oil, poly-α-olefin, polybutene, alkylbenzene, as long as the performance as a lubricating base oil is not hindered. Selected from the group consisting of synthetic hydrocarbons such as alkylnaphthalenes, isomerized oils of synthetic hydrocarbons obtained by the Fischer-Tropsch method, organic acid esters other than the present ester, polyalkylene glycols, polyphenylethers, alkylphenylethers, and silicone oils. One or two or more of these compounds can be used as a mixed base oil in appropriate combination. The proportion of the present ester in the mixed base oil is 5% by weight or more, and a suitable mixing ratio varies depending on the type of oil used in combination, but is usually 10% by weight or more, more preferably 20% by weight.
The above ratio is recommended.

The mineral oil base oil includes solvent refined mineral oil, hydrorefined mineral oil, and wax isomerized oil.
Those having a kinematic viscosity at 00 ° C. in the range of 1.5 to 40 mm ² / s, preferably 3 to 30 mm ² / s are used.

As the poly-α-olefin, a compound having 2 carbon atoms
Α-olefins (eg, ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, etc.) at 100 ° C. Kinematic viscosity of 1.5 to 40 mm ² / s and a viscosity index of 100 or more are exemplified.
Those having a viscosity index of 120 or more at ² / s are preferred.

Polybutene includes those obtained by polymerizing isobutylene and those obtained by copolymerizing isobutylene with normal butylene. Generally, the kinematic viscosity at 100 ° C. is 2 to 6000 mm.
There is a wide range of ² / s.

As the alkylbenzene, one having 1 to 4 carbon atoms
Monoalkylbenzenes, dialkylbenzenes, trialkylbenzenes, tetraalkylbenzenes, and the like, having a molecular weight of 200 to 450, substituted with 0 linear or branched alkyl groups are exemplified.

As the alkylnaphthalene, a compound having 1 to 1 carbon atoms is used.
Monoalkylnaphthalene and dialkylnaphthalene substituted with 30 linear or branched alkyl groups are exemplified.

Organic acid esters other than the present ester include straight-chain or branched-chain saturated or unsaturated fatty acids having 10 to 22 carbon atoms, such as palmitic acid, stearic acid and oleic acid, and straight-chain fatty acids having 3 to 22 carbon atoms. Monoesters with linear or branched saturated or unsaturated aliphatic alcohols; aliphatic dicarboxylic acids having 6 to 12 carbon atoms such as adipic acid, azelaic acid, sebacic acid, dodecane-2 acid, and 3 carbon atoms To 22 linear or branched saturated or unsaturated aliphatic alcohols; aromatic polycarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, and pyromellitic acid; Full ester of an anhydride and a linear or branched saturated or unsaturated aliphatic alcohol having 3 to 22 carbon atoms; cyclohexenedicarboxylic acid Diesters of cyclohexanedicarboxylic acids and their anhydrides with straight-chain or branched-chain saturated or unsaturated aliphatic alcohols having 3 to 22 carbon atoms; dimer acids and straight-chain or branched chains having 3 to 22 carbon atoms Alicyclic polycarboxylic acid esters such as esters with saturated or unsaturated aliphatic alcohols; and polyols such as neopentyl glycol, trimethylolpropane, pentaerythritol, ditrimethylolpropane, dipentaerythritol, and polyglycerin. Carbon number 3
It is possible to use up to 22 linear or branched saturated or unsaturated fatty acids, castor oil fatty acids, condensed castor oil fatty acids, full esters or partial esters with 12-hydroxystearic acid, and the like.

As the polyalkylene glycol, a ring-opened polymer of an alcohol and a linear or branched alkylene oxide having 2 to 4 carbon atoms is exemplified. Examples of the alkylene oxide include ethylene oxide, propylene oxide, and butylene oxide, and a polymer using one of these, or a copolymer using a mixture of two or more thereof can be used. Further, a compound in which the hydroxyl group at one or both ends is etherified or esterified can also be used.

Examples of the polyphenyl ether include compounds having a structure in which meta positions of two or more aromatic rings are connected by an ether bond or a thioether bond. Specifically, bis (m-phenoxyphenyl) ether, m -Bis (m-phenoxyphenoxy) benzene, and thioethers (commonly called C-ether) in which one or two or more of these oxygens are substituted with sulfur are exemplified.

Examples of the alkyl phenyl ether include compounds in which polyphenyl ether is substituted by a linear or branched alkyl group having 6 to 18 carbon atoms, and in particular, alkyl substituted by one or more alkyl groups. Diphenyl ether is preferred.

Examples of the silicone oil include dimethyl silicone, methylphenyl silicone, and modified silicones such as long-chain alkyl silicone and fluorosilicone.

In order to improve the performance of the lubricating oil composition according to the present invention, antioxidants other than amines, oil agents / friction modifiers, antiwear agents / extreme pressure agents, metal detergents, viscosity One or two of known additives such as an index improver, a pour point depressant, a metal deactivator, a metal corrosion inhibitor, a rust inhibitor, and a defoamer.
It is also possible to appropriately mix more than one species. The amount of such an additive is not particularly limited as long as it exhibits a predetermined effect, but the amount (% by weight based on the total weight of the lubricating oil composition) preferably applied is shown together with specific examples of the above-mentioned respective additives. .

Examples of the antioxidants other than the amine type include phenol type, phosphorus type and sulfur type antioxidants.
Phenols include 2,6-di-t-butylparacresol and 4,4′-methylenebis (2,6-di-t-
Butylphenol), 4,4'-bis (2,6-di-t
-Butylphenol), 4,4'-bis (2-methyl-
6-t-butylphenol), 2,2′-methylenebis (4-ethyl-6-t-butylphenol), 2,2 ′
-Methylenebis (4-methyl-6-t-butylphenol), 4,4'-butylidenebis (3-methyl6-t-
Butylphenol), 4,4′-thiobis (2-methyl-t-butylphenol) and the like. Examples of the phosphorus-based compound include di-t-butylphenylphosphite, triphenylphosphorothionate, and alkylated triphenylphosphorothionate. As a sulfur system,
Examples thereof include phenothiazine, sulfurized oil and fat, sulfurized olefin, dibenzyl disulfide, dicetyl sulfide, and the like. The amount of these additives may be 0.1 to 5% by weight.

Examples of the oily agent and friction modifier include aliphatic monocarboxylic acids such as stearic acid and oleic acid; aliphatic dibasic acids such as sebacic acid and dodecane-2-acid; alcohols such as stearyl alcohol and oleyl alcohol;
Examples thereof include amines such as oleylamine and organic molybdenum such as molybdenum dithiocarbamate. The amount of addition is 0.1 to 5.0% by weight.

Examples of the antiwear agent / extreme pressure agent include organic sulfur compounds such as olefin polysulfide, sulfurized oil and fat, dialkyl polysulfide, chlorinated paraffin, alkyl and aryl phosphites, zinc dialkyldithiophosphate, zinc dialkyldithiocarbamate. , A long-chain fatty acid-based compound is exemplified, and the addition amount thereof is 0.05 to
10% by weight.

The metal detergents include metal sulfonates,
Examples thereof include overbased metal sulfonates, metal phenates, overbased metal phenates, metal phosphonates, salicylates, carboxylates, and the like.
1 to 10% by weight.

Examples of the viscosity index improver include polyalkyl methacrylate, polyisobutylene, polyalkylstyrene, ethylene-propylene copolymer, and styrene-
Examples thereof include a butadiene copolymer-based compound and a styrene-maleic anhydride copolymer-based compound, and the added amount thereof is 1 to 20% by weight.

Examples of the pour point depressant include polyalkyl methacrylate, polyalkyl acrylate, condensate of chlorinated paraffin and naphthalene, condensate of chlorinated paraffin and phenol, polybutene, polyalkylstyrene, polyvinyl acetate and the like. The amount may be 0.1 to 1% by weight.

The metal deactivator used in the present invention includes benzotriazole which may have an alkyl substituent.
Benzotriazoles such as tetrahydrobenzotriazole, 2,5-bis (n-dodecyldithio) -1,3,3
Examples include thiadiazole-based compounds such as 4-thiadiazole, and benzotriazole is particularly preferred. The addition amount may be 0.01 to 0.4% by weight.

Examples of the rust preventive include sulfonate-based compounds, carboxylic acid-based compounds, organic amine soap-based compounds, and sorbitan partial ester-based compounds.
３3% by weight.

Examples of the antifoaming agent include silicone compounds such as polydimethylsilicone, and the amount of the defoaming agent is 1 to 100 ppm.

Since the lubricating oil composition according to the present invention has good oxidation stability and excellent abrasion resistance, it is suitable for use at high temperatures, and is particularly effective for lubricating oils for chains and the like.

[0059]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to the examples. The performance of various ester or lubricating oil compositions was evaluated by the following methods.

[Kinematic viscosity] JI was measured using an Ubbelohde viscometer.
The measurement was performed according to SK 2283.

[Pour point] The pour point was measured according to JIS K 2269.

[Oxidation stability test] Inside diameter: 33 mm, height: 8
0.1 g of sample oil and steel, aluminum, and copper wires each cut into 2 mm lengths are placed in a 5 mm glass test tube, and the stopper is closed. A stopper is attached so that the lid is not opened. Was. The test tube was placed in an oven and heated at 218 ° C. for 48 hours. The acid value of the sample oil after the test was measured, compared with the acid value before the oxidation test, and the increase value of the acid value was measured. Further, n-hexane (10 ml) was added to the sample oil after the test to dilute the oil, and the insoluble portion was changed to tar (% by weight). It is determined that the smaller the acid value increase value and the smaller the amount of tar generated, the better the oxidation stability.

[Volatility resistance test] Inner diameter 60 mm, height 4 m
1.0 g of the sample oil is placed in an aluminum dish of m and heated in an oven at 230 ° C. for 5 hours. The weight after the test was compared with that before the test, and the volatilization loss (%) was measured. The smaller the volatilization loss, the better the volatility resistance.

[Dispersion stability] After the solid dispersant is dispersed, the dispersion is allowed to stand for 7 days. The dispersion stability was evaluated by visually observing the state after 7 days. ◎: very good dispersibility ○: good dispersibility

Production Examples Esters AE were synthesized using the aromatic carboxylic acid components and monohydric alcohols shown in Table 1. Table 1 shows the kinematic viscosity, viscosity index and pour point of each ester.

[0066]

Example 1 The following components were dispersed in a mediamil to obtain a prototype oil A. Oxidation stability, volatility resistance, and dispersion stability of the prototype oil A were evaluated. The results are shown in Table 2. Base oil Ester A 94.7% by weight Additive N-phenyl-α-naphthylamine 1.0% by weight p, p′-dioctyldiphenylamine 1.0% by weight Tricresyl phosphate 1.0% by weight Benzotriazole 0.1% by weight Solid lubricant Boron nitride A (average particle diameter: 0.1 to 0.5 μm) 2.0% by weight Dispersant Benzylamine-based dispersant 0.2% by weight

[0068]

Example 2 The following components were dispersed in a medium mill to obtain a prototype oil B. Oxidation stability, volatilization resistance and dispersion stability of this prototype oil B were evaluated. The results are shown in Table 2. Base oil ester B 94.7% by weight Additive N-phenyl-α-naphthylamine 1.0% by weight p, p'-dioctyldiphenylamine 1.0% by weight Tricresyl phosphate 1.0% by weight Benzotriazole 0.1% by weight Solid lubricant Boron nitride A (average particle diameter: 0.1 to 0.5 μm) 2.0% by weight Dispersant Benzylamine-based dispersant 0.2% by weight

Example 3 The following components were dispersed with a mediadiamil to obtain a prototype oil C. Oxidation stability, volatilization resistance and dispersion stability of this prototype oil C were evaluated. The results are shown in Table 2. Base oil ester C 94.7% by weight Additive N-phenyl-α-naphthylamine 1.0% by weight p, p′-dioctyldiphenylamine 1.0% by weight Tricresyl phosphate 1.0% by weight Benzotriazole 0.1% by weight Solid lubricant Boron nitride A (average particle diameter: 0.1 to 0.5 μm) 2.0% by weight Dispersant Benzylamine-based dispersant 0.2% by weight

Example 4 The following components were dispersed in a mediamil to obtain a prototype oil D. Oxidation stability, volatilization resistance and dispersion stability of this prototype oil D were evaluated. The results are shown in Table 2. Base oil ester B 94.7% by weight Additive N-phenyl-α-naphthylamine 1.0% by weight p, p'-dioctyldiphenylamine 1.0% by weight Tricresyl phosphate 1.0% by weight Benzotriazole 0.1% by weight Solid lubricant Boron nitride B (average particle diameter: 18 to 22 μm) 2.0% by weight Dispersant Benzylamine-based dispersant 0.2% by weight

Example 5 The following components were dispersed in a mediamil to obtain a prototype oil E. Oxidation stability, volatility resistance, and dispersion stability of this prototype oil E were evaluated. The results are shown in Table 2. Base oil ester B 94.9% by weight Additive N-phenyl-α-naphthylamine 1.0% by weight p, p'-dioctyldiphenylamine 1.0% by weight Tricresyl phosphate 1.0% by weight Benzotriazole 0.1% by weight Solid lubricant Boron nitride A (average particle size: 0.1-0.5 μm) 2.0% by weight

Comparative Example 1 The following components were dispersed in a mediamil to obtain a prototype oil a. Oxidation stability, volatility resistance and dispersion stability of this comparative oil a were evaluated. The results are shown in Table 2. Base oil Ester D 94.7% by weight Additive N-phenyl-α-naphthylamine 1.0% by weight p, p'-dioctyldiphenylamine 1.0% by weight Tricresyl phosphate 1.0% by weight Benzotriazole 0.1% by weight Solid lubricant Boron nitride A (average particle diameter: 0.1 to 0.5 μm) 2.0% by weight Dispersant Benzylamine-based dispersant 0.2% by weight

Comparative Example 2 The following components were dispersed in a mediamil to obtain a prototype oil b. Oxidation stability, volatility resistance and dispersion stability of this comparative oil b were evaluated. The results are shown in Table 2. Base oil Ester 94.7% by weight Additive N-phenyl-α-naphthylamine 1.0% by weight p, p′-dioctyldiphenylamine 1.0% by weight Tricresyl phosphate 1.0% by weight Benzotriazole 0.1% by weight Solid lubricant Boron nitride A (average particle diameter: 0.1 to 0.5 μm) 2.0% by weight Dispersant Benzylamine-based dispersant 0.2% by weight

Comparative Example 3 The following components were dispersed in a mediamil to obtain a prototype oil c. Oxidation stability, volatility resistance and dispersion stability of this comparative oil c were evaluated. The results are shown in Table 2. Base oil Ester F 94.7% by weight Additive N-phenyl-α-naphthylamine 1.0% by weight p, p′-dioctyldiphenylamine 1.0% by weight Tricresyl phosphate 1.0% by weight Benzotriazole 0.1% by weight Solid lubricant Boron nitride A (average particle diameter: 0.1 to 0.5 μm) 2.0% by weight Dispersant Benzylamine-based dispersant 0.2% by weight

Comparative Example 4 The following components were mixed to obtain a prototype oil d. Oxidation stability and volatility resistance of this trial oil d were evaluated. The results are shown in Table 2. Base oil Ester A 96.9% by weight Additive N-phenyl-α-naphthylamine 1.0% by weight p, p'-dioctyldiphenylamine 1.0% by weight Tricresyl phosphate 1.0% by weight Benzotriazole 0.1% by weight

As is clear from the above Examples and Comparative Examples, the lubricating oil composition for chains comprising the present ester, an amine-based antioxidant and a solid lubricant has excellent heat stability at high temperatures, Since the stability is also good, it has become clear that a high-performance chain lubricating oil can be provided. In particular, in Comparative Example 4, the chain oil prepared without using a solid lubricant had poorer volatility than that of Example 1, indicating the importance of the solid lubricant. On the other hand, in Comparative Example 1, an ester D (polyol ester) was used as the base oil, and the same additives and solid lubricant as in Example 1 were mixed and dispersed, but the thermal stability was significantly poor. Comparative Example 2 was 3, 5,
This is a case where an aromatic ester containing a monohydric alcohol other than 5-trimethylhexanol as a component is used, but is significantly inferior in heat stability.

[0078]

Industrial Applicability The lubricating oil composition for chains according to the present invention has excellent heat stability at high temperatures and good volatility resistance.
Therefore, even under the condition of being exposed to a high temperature of 200 ° C. or more, the function as a chain lubricant can be sufficiently exhibited, and a high effect can be achieved in reducing lubrication and preventing seizure.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C10N 30:08 40:32 (72) Inventor Kazunari 13-13 Yoshishima Yakuracho, Fushimi-ku, Kyoto-shi, Kyoto New F-term (reference) in Nippon Rika Co., Ltd. 4H104 AA26C BB32A BB34A BE07C BH03C EA08C EB03 EB04 LA04 LA05 PA37

Claims (8)

[Claims] 1. One or two or more aromatic carboxylic acids and 50 mol% of 3,5,5-trimethylhexanol.
The total weight of the lubricating oil composition is added to a base oil containing an aromatic carboxylic acid ester obtained by completely esterifying the monohydric alcohol having a linear or branched alkyl group having 4 to 18 carbon atoms contained above. A lubricating oil composition for a chain, wherein 0.1 to 5% by weight of one or more amine antioxidants and 0.01 to 20% by weight of a solid lubricant are dispersed. . 2. The chain according to claim 1, wherein the one or more aromatic carboxylic acids are one or more selected from the group consisting of trimellitic acid, trimesic acid and pyromellitic acid. Lubricating oil composition. 3. The method according to claim 1, wherein the monohydric alcohol having a linear or branched alkyl group having 4 to 18 carbon atoms is 3, 5, 5
The lubricating oil composition for a chain according to claim 2, wherein the composition is trimethylhexanol alone. 4. An amine-based antioxidant comprising N-phenyl-
A compound selected from the group consisting of α-naphthylamine, N-octylphenyl-α-naphthylamine and p, p′-dioctyldiphenylamine.
The lubricating oil composition for a chain according to claim 3. 5. The solid lubricant has an average particle size of 0.01 to 0.01.
The lubricating oil composition for a chain according to any one of claims 1 to 4, which is 10 µm. 6. The lubricating oil composition according to claim 1, wherein the solid lubricant is boron nitride. 7. The method of dispersing a solid lubricant, wherein the dispersant and / or dispersion stabilizer is used in an amount of 0.01 to 5% by weight based on the total weight of the lubricating oil composition to disperse the solid lubricant. The lubricating oil composition for a chain according to claim 6, wherein 8. The lubricating oil composition according to claim 1, further comprising 0.1 to 10% by weight of one or more phosphate esters based on the total weight of the lubricating oil composition. Lubricating oil composition for chains.