JP2008056940A - High temperature lubricating oil composition - Google Patents

Abstract

（式中、Ｒ¹は炭素数６〜１６の直鎖状アルキル基を示し、ｎは１〜６の整数を示す。）で表される芳香族エステル化合物２０〜１００重量％及び（ｂ）その他の基油０〜８０重量％からなる基油組成物に、潤滑油組成物全量基準で、（ｃ）酸化防止剤０．１〜１０重量％を配合してなる高温用潤滑油組成物である。
【選択図】なしAn object of the present invention is to provide a lubricating oil composition for high temperature which has a thin film, the amount of evaporation at high temperature is suppressed, and the fluidity is maintained for a long time.
(A) The following general formula (I)

(Wherein R ¹ represents a linear alkyl group having 6 to 16 carbon atoms and n represents an integer of 1 to 6) and (b) other (C) 0.1 to 10% by weight of an antioxidant based on the total amount of the lubricating oil composition and a base oil composition comprising 0 to 80% by weight of the base oil of .
[Selection figure] None

Description

  The present invention relates to a high temperature lubricating oil composition, and more particularly to a high temperature lubricating oil composition used in chains, roller chains, chain conveyors, bearings, and the like.

Lubricating oils used in chains, roller chains, chain conveyors, bearings, etc. are exposed to high temperatures, and the amount of lubricating oil evaporated greatly affects the life of the equipment. Thus, under high temperature conditions, the lubricating oil loses its conventional viscosity and becomes a thin film, and the amount of evaporation must be suppressed under more severe conditions. As a conventional high-temperature lubricating oil, a high-viscosity and high-viscosity oil agent has been used in order to suppress evaporation. However, such an oil agent has a small amount of evaporation but a large power loss, which is not preferable when viewed as the total performance of the lubricating oil. In addition, when such oils are exposed to a thin film at a high temperature, they generally solidify although there is a large amount of residue, and not only lose their liquid properties, but they also become solidified sludge and reduce the flow of the oil. This will result in poor lubrication of the lubrication part. Therefore, there has been a demand for a high-temperature lubricating oil that has a thin film, the amount of evaporation at high temperature being suppressed, and the fluidity is maintained for a long time.

  The present invention has been made from the above viewpoint, and an object of the present invention is to provide a thin film, a high-temperature lubricating oil composition in which the amount of evaporation at high temperatures is suppressed and the fluidity is maintained for a long time. .

As a result of intensive studies, the present inventors have found that the object of the present invention can be effectively achieved by using a specific aromatic ester compound as a base oil, and have completed the present invention. That is, the gist of the present invention is as follows.
( 1 ) (a) The following general formula (I)

(In the formula, R ¹ represents a linear alkyl group having 6 to 16 carbon atoms, and n represents an integer of 1 to 6)
In the base oil composition comprising 20 to 100% by weight of the aromatic ester compound represented by the formula (b) and 0 to 80% by weight of the other base oil, (c) antioxidant 0. A high-temperature lubricating oil composition comprising 1 to 10% by weight.
( 2 ) The high temperature lubricating oil composition according to the above (1), wherein the base oil composition comprises (a) 30 to 80% by weight of the aromatic ester compound and (b) 20 to 70% by weight of the other base oil. object.
( 3 ) (a) The high temperature lubricating oil composition according to (1) or (2) above, wherein the aromatic ester compound is selected from trimellitic acid alkyl ester and pyromellitic acid alkyl ester.

( 4 ) (b) Any of the above (1) to (3), wherein the other base oil is one or more selected from α-olefin oligomers, ethylene-α-olefin oligomers, polybutenes and hydrides thereof. A high-temperature lubricating oil composition according to claim 1.
( 5 ) (c) The high temperature lubricating oil composition according to any one of the above (1) to (4), wherein the antioxidant contains sulfur and / or phosphorus in the molecule.
( 6 ) The lubricating oil composition for high temperature according to any one of (1) to (5), wherein the antioxidant is selected from dithiophosphates and thiophosphates.
( 7 ) The above (1) to ( 7 ), wherein the antioxidant is 2,6-di-tert-butyl-4- (4,6-bis (octylthio) -1,3,5-triazin-2-ylamino) phenol. (5) The lubricating oil composition for high temperature in any one of.

ADVANTAGE OF THE INVENTION According to this invention, the high temperature lubricating oil composition by which the evaporation amount under high temperature is suppressed and fluidity | liquidity is maintained for a long time can be provided.

The present invention is described in detail below. The base oil composition constituting the lubricating oil composition for high temperature of the present invention,
(A) 20 to 100% by weight of the aromatic ester compound represented by the general formula (I) and (b) 0 to 80% by weight of other base oils.

As for the aromatic carboxylic acid which comprises the aromatic ester compound of (a) component, the number of carboxylic acid couple | bonded with benzene has preferable 3 or 4, and especially trimellitic acid and pyromellitic acid are preferable. As the aliphatic alcohol used for the aromatic carboxylic acid ester, a linear or branched alcohol having 6 to 16 carbon atoms is preferable. Specifically, tri-n-hexyl trimellitate, tri-2-ethylhexyl trimellitate, tri-n-octyl trimellitate, tri-3,5,5-trimethylhexyl trimellitate, tetra-n-hexyl pyromellitate, Examples thereof include tetra-2-ethylhexyl pyromellitate, tetra n-octyl pyromellitate, and tetra 3,5,5-trimethylhexyl pyromellitate. In addition, the aromatic carboxylic acid ester may be used alone or in combination of two or more, and a partial ester may be included in the full ester.

(B) Other base oils are used as base oils for ordinary equipment oils and can be used regardless of mineral oil type or synthetic oil type. Mineral oil base oils include, for example, solvent oil removal, solvent extraction, hydrocracking of oil fractions obtained by atmospheric distillation or vacuum distillation of paraffinic, intermediate, and naphthenic crudes. Refined oil refined according to conventional methods such as solvent dewaxing, catalytic dewaxing, hydrorefining, sulfuric acid washing, and clay treatment can be used.

In addition, examples of the synthetic oil base oil include various kinds such as α-olefin oligomer, ethylene-α-oligomer, polybutene, dibasic acid ester, polyalkylene glycol, hindered ester, alkylbenzene, alkylnaphthalene, and polyether. Can be used. Among these, α-olefin oligomers, ethylene-α-oligomers, polybutenes or hydrides thereof are preferable in that fluidity can be maintained for a long period of time. In addition, (b) component may mix 1 type, or 2 or more types, and may mix and use mineral oil and synthetic oil.
The proportion of (a) aromatic carboxylic acid ester compound and (b) other base oil is (b) component 0 to 80% by weight with respect to component (a) 20 to 100% by weight, preferably component (a). It is 20-70 weight% of (b) component with respect to 30-80 weight%. When the component (a) is less than 20% by weight, the effect of the present invention cannot be obtained.

  Next, amine antioxidants and phenolic antioxidants can also be used as the antioxidant of the component (c) blended in the base oil, but those containing sulfur and / or phosphorus in the molecule in terms of effect. Is preferred. Examples of amine-based antioxidants include monooctyl diphenylamine; monoalkyldiphenylamines such as monononyldiphenylamine; 4,4′-dibutyldiphenylamine; 4,4′-dipentyldiphenylamine; 4,4′-dihexyldiphenylamine; 4,4′-dioctyldiphenylamine; dialkyldiphenylamines such as 4,4′-dinonyldiphenylamine; tetrabutyldiphenylamine; tetrahexyldiphenylamine; tetraoctyldiphenylamine; polyalkyldiphenylamines such as tetranonyldiphenylamine; α-naphthylamine; phenyl-α-naphthylamine; butylphenyl-α-naphthylamine; pentylphenyl-α-naphthylamine It can be mentioned naphthylamine such as nonylphenyl -α- naphthylamine; hexylphenyl -α- naphthylamine; heptylphenyl -α- naphthylamine; octylphenyl -α- naphthylamine.

  Examples of phenolic antioxidants include 2,6-di-tert-butyl-4-methylphenol; monophenols such as 2,6-di-tert-butyl-4-ethylphenol, and 4,4′-methylenebis. Examples include diphenols such as (2,6-di-tert-butylphenol); 2,2′-methylenebis (4-ethyl-6-tert-butylphenol).

  The antioxidant containing sulfur and / or phosphorus in the molecule may be any additive that contains sulfur and / or phosphorus in the molecule and has an antioxidant ability, and is added for other purposes. No problem. First, antioxidants containing sulfur in the molecule are described. For example, sulfurized fats and oils, sulfurized mineral oils, sulfurized fatty acids, sulfurized esters, sulfurized olefins, dihydrocarbyl polysulfides, thiadiazole compounds, alkylthiocarbamoyl compounds, triazine compounds, thioterpene compounds, dialkylthiols. Examples thereof include dipropionate compounds.

  Here, sulfurized fats and oils are obtained by reacting sulfur and sulfur-containing compounds with fats and oils (lard oil, whale oil, vegetable oil, fish oil, etc.), and the sulfur content is not particularly limited, but generally 5 to 30 weights. % Is preferred. Specific examples thereof include sulfurized lard, sulfurized rapeseed oil, sulfurized castor oil, sulfurized soybean oil, and sulfurized rice bran oil. Examples of the sulfurized fatty acid include sulfurized oleic acid, and examples of the sulfurized ester include sulfurized methyl oleate and sulfurized rice bran fatty acid octyl.

As the sulfurized olefin, for example, the following general formula (II)
R ² -S _a -R ³ (II)
(Wherein R ² represents an alkenyl group having 2 to 15 carbon atoms, R ³ represents an alkyl group or alkenyl group having 2 to 15 carbon atoms, and a represents an integer of 1 to 8), etc. Can be mentioned. This compound is obtained by reacting an olefin having 2 to 15 carbon atoms or a dimer or tetramer thereof with a sulfurizing agent such as sulfur or sulfur chloride, and propylene, isobutene, diisobutene and the like are preferable.

Dihydrocarbyl polysulfide is represented by the following general formula (III):
R ⁴ -S _b -R ⁵ (III)
(In the formula, R ⁴ and R ⁵ are each an alkyl group having 1 to 20 carbon atoms or a cyclic alkyl group, an aryl group having 6 to 20 carbon atoms, an alkylaryl group having 7 to 20 carbon atoms, or 7 to 20 carbon atoms. An arylalkyl group, which may be the same or different from each other, and b represents an integer of 2 to 8)
It is a compound represented by these. Here, when R ⁴ and R ⁵ are alkyl groups, they are referred to as alkyl sulfides.

Specific examples of R ⁴ and R ⁵ in the general formula (III) include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, Various pentyl groups, various hexyl groups, various heptyl groups, various octyl groups, various nonyl groups, various decyl groups, various dodecyl groups, cyclohexyl groups, cyclooctyl groups, phenyl groups, naphthyl groups, tolyl groups, xylyl groups, benzyl groups, Examples thereof include a phenethyl group.

  Preferred examples of the dihydrocarbyl polysulfide include dibenzyl polysulfide, various dinonyl polysulfides, various didodecyl polysulfides, various dibutyl polysulfides, various dioctyl polysulfides, diphenyl polysulfide, dicyclohexyl polysulfide, and the like. As the thiadiazole compound, for example, the following general formula (IV)

(Wherein R ⁶ and R ⁷ each represent a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, and c and d each represent an integer of 0 to 8, respectively) 1, 3, 4-thiadiazole and 1,2,4-thiadiazole compounds are preferably used. Specific examples of such thiadiazole compounds include 2,5-bis (n-hexyldithio) -1,3,4-thiadiazole, 2,5-bis (n-octyldithio) -1,3,4-thiadiazole. 2,5-bis (n-nonyldithio) -1,3,4-thiadiazole, 2,5-bis (1,1,3,3-tetramethylbutyldithio) -1,3,4-thiadiazole, 3, , 5-bis (n-hexyldithio) -1,2,4-thiadiazole, 3,5-bis (n-octyldithio) -1,2,4-thiadiazole, 3,5-bis (n-nonyldithio)- Preferred examples include 1,2,4-thiadiazole and 3,5-bis (1,1,3,3-tetramethylbutyldithio) -1,2,4-thiadiazole.
Examples of the alkylthiocarbamoyl compound include the following general formula (V)

(Wherein R ^{8 to} R ¹¹ each represents an alkyl group having 1 to 20 carbon atoms, and e represents an integer of 1 to 8) are preferably used. Specific examples of such alkylthiocarbamoyl compounds include bis (dimethylthiocarbamoyl) monosulfide, bis (dibutylthiocarbamoyl) monosulfide, bis (dimethylthiocarbamoyl) disulfide, bis (dibutylthiocarbamoyl) disulfide, and bis (diamil). Preferred examples include thiocarbamoyl) disulfide and bis (dioctylthiocarbamoyl) disulfide.

  Preferred examples of the triazine compound include 2,6-di-tert-butyl-4- (4,6-bis (octylthio) -1,3,5-triazin-2-ylamino) phenol. Furthermore, examples of the thioterpene compound include a reaction product of phosphorus pentasulfide and pinene, and examples of the dialkylthiodipropionate compound include dilauryl thiodipropionate and distearyl thiodipropionate.

  In addition, as containing sulfur and metal, zinc dialkyldithiocarbamate (Zn-DTC), molybdenum dialkyldithiocarbamate (Mo-DTC), lead dialkyldithiocarbamate, tin dialkyldithiocarbamate, sodium sulfonate, calcium sulfonate, etc. are used. You can also Next, an antioxidant containing phosphorus in the molecule will be described. Typical examples are phosphate esters and amine salts thereof.

  The phosphoric acid esters include phosphoric acid esters, acidic phosphoric acid esters, phosphorous acid esters, and acidic phosphorous acid esters represented by the following general formulas (VI) to (X).

In the above general formulas (VI) to (X), R ^{12 to} R ¹⁴ represent an alkyl group, alkenyl group, alkylaryl group and arylalkyl group having 4 to 30 carbon atoms, and R ^{12 to} R ¹⁴ are the same or different. May be. Examples of the phosphate ester include triaryl phosphate, trialkyl phosphate, trialkylaryl phosphate, triarylalkyl phosphate, and trialkenyl phosphate. Specifically, for example, triphenyl phosphate, tricresyl phosphate, benzyldiphenyl phosphate, Ethyl diphenyl phosphate, tributyl phosphate, ethyl dibutyl phosphate, cresyl diphenyl phosphate, dicresyl phenyl phosphate, ethyl phenyl diphenyl phosphate, diethyl phenyl phenyl phosphate, propyl phenyl diphenyl phosphate, dipropyl phenyl phenyl phosphate, triethyl phenyl phosphate, tripropyl phenyl phosphate , Butylphenyl Phenyl phosphate, dibutylphenyl phenyl phosphate, tributylphenyl phosphate, trihexyl phosphate, tri (2-ethylhexyl) phosphate, tridecyl phosphate, trilauryl phosphate, trimyristyl phosphate, tripalmityl phosphate, tristearyl phosphate, trioleyl phosphate, etc. Can be mentioned.

  Specific examples of the acidic phosphate ester include 2-ethylhexyl acid phosphate, ethyl acid phosphate, butyl acid phosphate, oleyl acid phosphate, tetracosyl acid phosphate, isodecyl acid phosphate, lauryl acid phosphate, tridecyl acid phosphate. , Stearyl acid phosphate, isostearyl acid phosphate, and the like.

  Specific examples of the phosphite ester include triethyl phosphite, tributyl phosphite, triphenyl phosphite, tricresyl phosphite, tri (nonylphenyl) phosphite, tri (2-ethylhexyl) phosphite, tri Examples thereof include decyl phosphite, trilauryl phosphite, triisooctyl phosphite, diphenylisodecyl phosphite, tristearyl phosphite, and trioleyl phosphite.

Specific examples of the acidic phosphite include dibutyl hydrogen phosphite, dilauryl hydrogen phosphite, dioleyl hydrogen phosphite, distearyl hydrogen phosphite, diphenyl hydrogen phosphite and the like.
Furthermore, examples of amines that form amine salts with these include, for example, the general formula (XI)
R ¹⁵ _m NH _3-m (XI)
(In the formula, R ¹⁵ represents an alkyl group or alkenyl group having 3 to 30 carbon atoms, an aryl group or arylalkyl group having 6 to 30 carbon atoms, or a hydroxyalkyl group having 2 to 30 carbon atoms, and m represents 1, 2 or 3 shows a. also, if R ¹⁵ is plural, R ¹⁵ is mono-substituted amine represented by the even may be different.) in the same, disubstituted amines or trisubstituted amines. The alkyl group or alkenyl group having 3 to 30 carbon atoms in R ¹⁵ in the general formula (XI) may be linear, branched or cyclic.

  Here, examples of the mono-substituted amine include butylamine, pentylamine, hexylamine, cyclohexylamine, octylamine, laurylamine, stearylamine, oleylamine, and benzylamine. Examples of the disubstituted amine include Dibutylamine, dipentylamine, dihexylamine, dicyclohexylamine, dioctylamine, dilaurylamine, distearylamine, dioleylamine, dibenzylamine, stearyl monoethanolamine, decyl monoethanolamine, hexyl monopropanolamine, benzyl Examples include monoethanolamine, phenyl monoethanolamine, tolyl monopropanol, and the like. Examples of tri-substituted amines include tributylamine, tripentylamine, trihexylamine, tricyclohexylamine, trioctylamine, trilaurylamine, tristearylamine, trioleylamine, tribenzylamine, dioleyl monoethanolamine, dilauryl.・ Monopropanolamine, dioctyl monoethanolamine, dihexyl monopropanolamine, dibutyl monopropanolamine, oleyl diethanolamine, stearyl dipropanolamine, lauryl diethanolamine, octyl dipropanolamine, butyl diethanolamine, benzyl diethanolamine , Phenyl diethanolamine, tolyl dipropanolamine, xylyl diethanolamine It may be mentioned triethanolamine, tripropanolamine and the like.

  Examples of those containing phosphorus and halogen atoms include chlorinated phosphates. Examples of antioxidants containing sulfur and phosphorus in the molecule include phosphosulfurized fats and oils, phosphosulfurized olefins, and thiophosphates (thiophosphites, thiophosphates). Among them, thiophosphites (alkyl type), Thiophosphate (alkylaryl type) is preferred.

  Dithiophosphates such as zinc dithiophosphate (Zn-DTP), molybdenum dithiophosphate (Mo-DTP), lead dithiophosphate, tin dithiophosphate, etc. can be mentioned as those containing sulfur, phosphorus, and metals, among which alkyl Those having an aryl group are preferred. Among the above-mentioned antioxidants, 2,6-tert-butyl-4- (4,6-bis (octylthio) -1,3,5-triazine-2 is effective in suppressing the amount of evaporation. -Ilamino) phenol, Zn-DTP (alkylaryl type), thiophosphite (alkyl type), thiophosphate (alkylaryl type) are preferred.

  Moreover, the above antioxidant can be used individually or in combination of 2 or more types. The preferable compounding amount of the above antioxidant is in the range of 0.1 to 10% by weight based on the total amount of the composition. If the blending amount is less than 0.1% by weight, the object of the present invention is not sufficiently exerted, and if the blending amount exceeds 10% by weight, the effect may not be improved for the amount. Oil solubility may be reduced. A more preferable blending amount is in the range of 1 to 7% by weight.

  In the lubricating oil composition for high temperature of the present invention, various known additives such as a rust preventive, a detergent / dispersant, a metal deactivator, and an antifoaming agent are added to the lubricating oil composition of the present invention as long as the purpose of the present invention is not impaired. It can mix | blend suitably. Examples of the rust inhibitor include metal sulfonates and succinates.

  Examples of the cleaning dispersant include metal sulfonate, metal salicylate, metal finate, and succinimide. Examples of the metal deactivator include benzotriazole and thiadiazole. Examples of antifoaming agents include methyl silicone oil, fluorosilicone oil, and polyacrylate.

In order to achieve the object, the high temperature lubricating oil composition of the present invention preferably has a kinematic viscosity at 40 ° C. adjusted to 10 to 500 mm ² / s. More preferably, it is the range of 50-320 mm < ² > / s. In addition, the lubricating oil composition for high temperature of this invention is used suitably, when it becomes the temperature exceeding 150 degreeC in 50% or more time during a use period.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
Examples 1 to 6 and Comparative Examples 1 and 2
As shown in Table 1, a lubricating oil composition was prepared by blending an antioxidant with the base oil. Regarding the viscosity of the composition, the kinematic viscosity at 40 ° C. was adjusted to 220 mm ² / s by adjusting and blending the viscosity of the α-olefin oligomer. About the composition, the thin film residue test was done in the following way. Further, the container was tilted, and the presence or absence of fluidity at that time was judged visually. The results are shown in Table 1.
Thin Film Residue Test Using the container and constant temperature air bath shown in the lubricating oil thermal stability test of JIS K 2540, the amount of residue at 200 ° C. for 24 hours was measured with a sample amount of 1 g. It was expressed as a percentage and used as the residue rate. During the measurement, air was constantly introduced at 10 liter / hr.

(note)
* 1 1-decene oligomer hydride (kinematic viscosity at 40 ° C. 30-63 mm ² / s)
* 2 Number average molecular weight: 2,300
* 3 Tri n-octyl trimellitate * 4 Tri n-octyl pyromellitate * 5 4,4'-methylenebis (2,6-di-tert-butylphenol)
* 6 4,4'-Dibutyldiphenylamine * 7 Alkyl aryl type Zn-DTP
* 8 Triisononylphenol thiophosphate * 9 2,6-di-tert-butyl-4- (4,6-bis (octylthio) -1,3,5-triazin-2-ylamino) phenol

  ADVANTAGE OF THE INVENTION According to this invention, the high temperature lubricating oil composition by which the evaporation amount under high temperature is suppressed and fluidity | liquidity is maintained for a long time can be provided.

Claims (7)

(A) The following general formula (I)

(Wherein R ¹ represents a linear alkyl group having 6 to 16 carbon atoms and n represents an integer of 1 to 6) and (b) other A high temperature lubricating oil composition comprising (c) 0.1 to 10% by weight of an antioxidant based on the total amount of the lubricating oil composition in a base oil composition consisting of 0 to 80% by weight of the base oil. The lubricating oil composition for high temperature according to claim 1, wherein the base oil composition comprises (a) 30 to 80% by weight of the aromatic ester compound and (b) 20 to 70% by weight of the other base oil. The lubricating oil composition for high temperature according to claim 1 or 2, wherein the aromatic ester compound (a) is selected from trimellitic acid alkyl ester and pyromellitic acid alkyl ester. (B) Other base oils are 1 type, or 2 or more types chosen from alpha-olefin oligomer, ethylene-alpha-olefin oligomer, polybutene, and these hydrides, For high temperature in any one of Claims 1-3 Lubricating oil composition. (C) Antioxidant is what contains sulfur and / or phosphorus in a molecule | numerator, The lubricating oil composition for high temperatures in any one of Claims 1-4. (C) Antioxidant is chosen from dithiophosphate and thiophosphate ester, The high temperature lubricating oil composition in any one of Claims 1-5. (C) The antioxidant is 2,6-di-tert-butyl-4- (4,6-bis (octylthio) -1,3,5-triazin-2-ylamino) phenol. The lubricating oil composition for high temperature according to any one of the above.