KR101412266B1 - Hydraulic oil composition - Google Patents

Abstract

The present invention relates to a base oil having a sulfur content of less than 0.03 mass%, a saturated fraction of 90 mass% or more, a viscosity index of 80 or more, and an absolute viscosity of 1 to 1000 mPa 에서 at 40 캜, (A) (C) 1 to 20% by mass of a polymethacrylate-based viscosity index improver for a specific acrylic acid ester, (B) 0.005 to 5% by mass of an acid amide compound, (C) 0.005 to 5% by mass of an acidic phosphorous acid ester compound, and (D) 0.005 to 5% by mass of at least one selected from polyhydric alcohol esters, alkanolamines, olefin sulfates and thiocarbamate compounds. will be. In addition, the present invention relates to a hydraulic operating oil composition that satisfactorily satisfies energy saving, heat stability (sludge resistance), abrasion resistance, skirting resistance, water separability and friction reduction property of a sliding part required for a hydraulic operating oil.

Hydraulic oil composition, energy saving, thermal stability, sludge resistance, abrasion resistance, scuffing resistance, water separability, friction reduction property

Description

HYDRAULIC OIL COMPOSITION [0001]

The present invention relates to a hydraulic fluid composition, and more particularly to a hydraulic fluid composition having good energy saving, thermal stability (sludge resistance), abrasion resistance, scuffing resistance, water separability and friction reducing properties , A hydraulic machine field, a machine tool field, an industrial machine field, and the like.

Hydraulic fluid is a power transmission fluid used for power transmission, power control, buffering, etc. of hydraulic systems such as hydraulic devices and devices, and also performs the lubrication function of sliding parts.

In the hydraulic circuit, there is a sliding part such as a metal-metal or metal-rubber (resin) in a pump, a control valve, a hydraulic cylinder and the like. The hydraulic operating fluid used in such a hydraulic circuit is required to have satisfactory friction characteristics such as abrasion resistance, abrasion resistance, and frictional reduction property in these sliding portions.

In recent years, the hydraulic operating system has become more and more sophisticated. In order to perform high-speed and precise control, a case for controlling the flow rate and direction of the hydraulic system by a spool valve or the like, and a servo valve The number of cases is increasing. Since the performance of the spool valve and the servo valve is significantly lowered when the sludge is generated in the hydraulic operating oil, the hydraulic operating oil used has excellent friction characteristics and hydraulic squeeze oil excellent in sludge which can suppress the formation of sludge It is strongly demanded.

Further, from the viewpoint of energy conservation, it has been required to reduce the resistance at the sliding portion and to improve the performance of the hydraulic oil, such as reduction of loss energy and suppression of increase of oil temperature.

Conventionally, zinc dithiophosphate (ZnDTP) has been widely used as an abrasion preventing agent for hydraulic operating oil. However, ZnDTP causes sludge generation and can not be used for a long time by mixing with hydraulic oil. Further, the effect of preventing wear due to the use of ZnDTP is due to the formation of a hard film such as iron phosphate on the metal surface. However, since the coefficient of friction of the sliding portion increases due to the formation of the film, it is preferable from the viewpoint of energy saving There is also something that can not be done.

Therefore, studies have been made on hydraulic oil using a so-called via-based abrasion preventing agent that does not use ZnDTP.

For example, there has been proposed a hydraulic operating oil in which an aromatic phosphoric acid ester, a phosphorous acid ester and an amine salt thereof, a thiophosphate, a? -Dithiophosphorylated propionic acid compound and the like are compounded as an abrasion preventing agent instead of ZnDTP (for example, Patent Document 1 , 2 and 3).

However, these hydraulic operating fluids do not sufficiently satisfy the friction characteristics such as sludge resistance (sludge suppressing property) and abrasion resistance, and they are not yet improved as hydraulic operating fluids that can cope with high performance and energy saving of the hydraulic operating system There is room for.

Further, a composition using an antioxidant, a phosphorus-based compound and / or a sulfur-based compound and N-oleyl sarcosine in combination (for example, see Patent Document 4) instead of ZnDTP, and a composition containing a phosphorus-containing carboxylic acid compound and a dispersion- (See, for example, Patent Document 5).

However, even these hydraulic operating oils can not sufficiently have friction characteristics such as sludge resistance (sludge suppressing property) and abrasion resistance.

Accordingly, it has been found that a satisfactory balance of energy saving, heat stability (resistance to sludge), abrasion resistance, abrasion resistance (skirting resistance), water separability and friction reducing property required for hydraulic operating oil are found It is a reality that can not be done.

Patent Document 1: JP-A-10-67993

Patent Document 2: JP-A-11-217577

Patent Document 3: Japanese Patent Application Laid-Open No. 2002-265971

Patent Document 4: JP-A-2002-129180

Patent Document 5: Japanese Patent Application Laid-Open No. 2005-307203

DISCLOSURE OF THE INVENTION <

[PROBLEMS TO BE SOLVED BY THE INVENTION]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a process for producing a hydraulic oil composition which satisfactorily satisfies energy saving, heat stability (resistance to sludge), abrasion resistance, resistance to abrasion (skirting resistance), water separability, And to provide a hydraulic oil composition.

MEANS FOR SOLVING THE PROBLEMS [

The inventors of the present invention have conducted intensive studies to develop a hydraulic operating fluid composition that satisfies the required performance of the hydraulic fluid in a balanced manner. As a result, it has been found that a polymethacrylate viscosity index improver having a specific molecular weight in a base oil having a specific property It has been found that the object can be attained by blending the acid amide compound, the specific phosphoric acid ester compound or the like and the specific lubricity improving agent at a predetermined ratio, respectively. The present invention has been completed based on this finding.

That is,

[1] A process for producing a base oil having a sulfur content of less than 0.03 mass%, a saturated fraction of 90 mass% or more, a viscosity index of 80 or more, and an absolute viscosity at 40 캜 of 1 to 1000 mPa 와,

(A) 1 to 20% by mass of a polymethacrylate-based viscosity index improver having a weight average molecular weight of 10,000 to 50,000 and

(B) 0.005 to 5% by mass of an acid amide compound and

(C) from 0.005 to 5% by mass of (c-1) an acidic phosphate ester compound represented by formula (IIa) and / or (c-2) an acidic phosphorous acid ester compound represented by formula

(D) 0.005 to 5% by mass of at least one selected from polyhydric alcohol esters, alkanolamines, olefin sulfates and thiocarbamate compounds, and

(Wherein R ¹ represents a hydrogen atom or a hydrocarbon group of 1 to 18 carbon atoms and R ² represents a hydrocarbon group of 1 to 18 carbon atoms)

(Wherein R ³ represents a hydrogen atom or a hydrocarbon group of 1 to 18 carbon atoms and R ⁴ represents a hydrocarbon group of 1 to 18 carbon atoms)

[2] The hydraulic fluid according to [1], further comprising 0.005 to 5% by mass of at least one selected from the amine salt of the acid phosphate ester compound (E) and the phosphoric acid triester compound represented by the formula (IV) Composition

.

(Wherein R ⁷ to R ⁹ each independently represent a hydrocarbon group of 1 to 18 carbon atoms)

EFFECTS OF THE INVENTION [

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a water-repellent and water-repellent film having good energy saving, heat stability (sludge resistance), abrasion resistance, It is possible to provide a hydraulic operating oil composition preferably used for industrial machinery fields and the like.

BEST MODE FOR CARRYING OUT THE INVENTION [

The hydraulic oil composition of the present invention comprises a base oil and at least one additive selected from the group consisting of (A) a polymethacrylate-based viscosity index improver, (B) an acid amide compound, (C) an acidic phosphate ester compound and / A phosphorus ester compound and (D) a lubricity improving agent.

The base oil used in the hydraulic fluid composition of the present invention requires a sulfur content of less than 0.03 mass%, a saturated content of 90 mass% or more, a viscosity index of 80 or more, and an absolute viscosity of 1 to 1000 mPa.s at 40 占 폚.

If the sulfur content of the base oil is 0.03 mass% or more or the saturated content is less than 90 mass%, the oxidation stability is poor, the acid value increases and the sludge is generated, and the corrosiveness against non-ferrous metals increases, It does not. The sulfur content is preferably 0.02 mass% or less, and more preferably 0.01 mass% or less. The saturated content is preferably 95 mass% or more, and more preferably 98 mass% or more.

The sulfur content is a value measured in accordance with JIS K 2541, and the saturated content is a value measured in accordance with ASTM D 2007.

If the viscosity index of the base oil is less than 80, there is a fear that the viscosity at low temperature is lowered and the lubricating performance is deteriorated. On the other hand, when the base oil is low temperature, the viscosity becomes high, From the viewpoint of widening the usable temperature range from low temperature to high temperature, the viscosity index is preferably 100 or more, more preferably 120 or more.

The viscosity index is a value measured in accordance with &quot; Petroleum Product Kinetic Viscosity Test Method &quot; specified in JIS K 2283.

If the absolute viscosity of the base oil at 40 캜 is less than 1 mPa s, the lubrication performance deteriorates and there is a possibility that abnormal wear or scorching may occur, and the risk of fire is high. On the other hand, if it exceeds 1000 mPa · s, the viscous resistance becomes large at low temperature and it becomes difficult to suck it into the pump, which may cause malfunction of the machine. The absolute viscosity at 40 캜 is preferably from 3 to 500 mPa 하고, more preferably from 5 to 300 mPa s, still more preferably from 10 to 150 mPa 가, from the viewpoint of friction characteristics, fire risk and viscous resistance at low temperatures More preferable.

As the base oil, both mineral oils and synthetic oils can be used as long as they have the above properties. Examples of the mineral oil include paraffinic mechanical mineral oil, intermediate mechanical mineral oil, and naphthenic mechanical mineral oil obtained by a conventional purification method such as solvent purification and hydrogenation purification, and the like. .

Examples of the synthetic oil include polybutene, polyolefin (? -Olefin (co) polymer), various esters (e.g., polyol ester, dibasic acid ester, phosphoric acid ester and the like), various ethers Etc.), and slack waxes or isomeric products of GTL WAX.

In the present invention, one or more of the above-mentioned mineral oils may be used as the base oil, or a combination of two or more thereof may be used. The above synthetic oils may be used alone or in combination of two or more. Further, at least one mineral oil and at least one synthetic oil may be used in combination.

In the hydraulic fluid composition of the present invention, the polymethacrylate-based viscosity index improver as the component (A) has a weight average molecular weight in the range of 10,000 to 50,000, and examples thereof include polymethacrylate, Polymethacrylates, and the like. When the weight average molecular weight is less than 10,000, the viscosity index improving effect may not be sufficiently exhibited. When the weight average molecular weight is more than 50,000, the polymer may be broken during use and the viscosity index improving effect may not be exhibited. A preferred weight average molecular weight is from 20,000 to 40,000.

The weight average molecular weight is a value measured in terms of polystyrene as measured by a gel permeation chromatography (GPC) method.

In the present invention, when dispersed polymethacrylate is used, there is no particular limitation, and for example, a copolymer of methacrylate and a nitrogen-containing monomer having an ethylenic unsaturated bond can be mentioned.

Examples of the nitrogen-containing monomer having an ethylenically unsaturated bond include dimethylaminomethyl methacrylate, diethylaminomethyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, 2-methyl-5-vinylpyridine , Morpholino methyl methacrylate, morpholino ethyl methacrylate, N-vinyl pyrrolidone, and mixtures thereof.

The copolymerization ratio of the methacrylate and the nitrogen-containing monomer having the ethylenically unsaturated bond is preferably from 80:20 to 95: 5 by mass ratio.

In the hydraulic fluid composition of the present invention, the polymethacrylate-based viscosity index improver of component (A) may be used singly or in combination of two or more. The blending amount thereof is selected in the range of 1 to 20% by mass based on the total amount of the composition. When the blending amount is less than 1% by mass, the effect of improving the viscosity index is not sufficiently exhibited. On the other hand, when the blending amount is more than 20% by mass, the effect is not improved in the distribution thereof.

The blending amount of the component (A) is preferably 1 to 15 mass%, and more preferably 2 to 10 mass%.

In the hydraulic fluid composition of the present invention, the acid amide compound of the component (B) is preferably a condensation reaction product of a fatty acid and a polyalkylene polyamine, and examples thereof include a fatty acid having 8 to 24 carbon atoms, And condensation reaction products with polyethylene polyamines.

H ₂ N (CH ₂ CH ₂ NH) _n H

(Wherein n represents the number of the average value of 2 to 6)

The fatty acids having 8 to 24 carbon atoms include straight chain or branched saturated and unsaturated fatty acids, and examples thereof include octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid, octadecanoic acid (Stearic acid), hydroxyoctadecanoic acid, icosanoic acid, hexanoic acid, docosanoic acid, tricoic acid, tetracosanoic acid, octenoic acid, decenoic acid, dodecenoic acid, tetradecenoic acid, hexadecenoic acid, ), Straight-chain saturated and unsaturated fatty acids such as nonadecenic acid, icosenic acid, hexenecosenic acid, docosenoic acid, tricosenic acid and tetracosenoic acid, and branched fatty acids corresponding thereto.

Of these, isostearic acid, which is a branched fatty acid having a total of 18 carbon atoms, is preferred.

On the other hand, specific examples of the polyethylenepolyamine represented by the above formula (I) include, for example, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine and the like.

The acid amide compound (B) used in the hydraulic oil composition of the present invention is preferably a reaction product comprising the fatty acid and the polyalkylene polyamine as reaction raw materials. The reaction product can be condensed with a fatty acid and a polyalkylene polyamine by a known method. For example, the reaction is carried out at a reaction temperature of 100 to 150 ° C and a reaction time of 1 to 5 hours. In this case, the ratio of the fatty acid as the reaction raw material to the polyalkylene polyamine is arbitrary, but it is preferable that the polyalkylene polyamine is slightly excessive.

In the present invention, the acid amide compounds of the component (B) may be used singly or in combination of two or more kinds. The amount of the component (B) is in the range of 0.005 to 5 mass%, preferably 0.01 to 5 mass%, and more preferably 0.02 to 3 mass%, based on the entire composition.

In the hydraulic oil composition of the present invention, the acidic phosphate ester compound (c-1) in the component (C) is a compound represented by the general formula (IIa).

<Formula IIa>

R ¹ in the above formula (IIa) is a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms, and R ² is a hydrocarbon group having 1 to 18 carbon atoms. Examples of the hydrocarbon group having 1 to 18 carbon atoms include an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, and an aralkyl group having 7 to 18 carbon atoms. The alkyl group and the alkenyl group may be any of linear, branched and cyclic, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n- butyl group, an isobutyl group, An allyl group, a propyl group, an isopropyl group, a butyl group, a pentyl group, various hexyl groups, various octyl groups, various decyl groups, various dodecyl groups, various tetradecyl groups, various hexadecyl groups, various octadecyl groups, cyclopentyl groups, A phenyl group, a butenyl group, various hexenyl groups, various octenyl groups, various decenyl groups, various dodecenyl groups, various tetradecenyl groups, various hexadecenyl groups, various octadecenyl groups, cyclopentenyl groups, cyclohexenyl groups And the like.

Examples of the aryl group having 6 to 18 carbon atoms include a phenyl group, a tolyl group, a xylyl group and a naphthyl group. Examples of the aralkyl group having 7 to 18 carbon atoms include a benzyl group, a phenethyl group, a naphthylmethyl group, A benzyl group, a methylphenethyl group, a methylnaphthylmethyl group and the like.

The total number of carbon atoms of R ¹ and R ² is preferably in the range of 3 to 36, and therefore it is preferable that R ¹ and R ² are each a suitable group so that the total carbon number thereof is in the range of 3 to 36.

The acidic phosphate ester compound of formula (IIa) is an acidic phosphate monoester or an acidic phosphate diester.

Examples of the acidic phosphoric acid mono and diesters include mono (di) n-propyl acid phosphate, mono (di) n-butyl acid phosphate, mono (di) -2- ethylhexyl acid phosphate, Mono (di) stearyl acid phosphate, mono (di) stearyl acid phosphate, mono (di) stearyl acid phosphate, mono Oleic acid phosphate, and the like.

Among the components (C), the acid phosphite ester compound (c-2) is a compound represented by the formula (IIb).

<Formula IIb>

R ³ in Formula (IIb) is the same as R ¹ in Formula (IIa), and R ⁴ in Formula (IIb) is Is the same as R &lt; ² &gt; in the above formula (IIa). The total carbon number of R ³ and R ⁴ is also the same as in the case of the acidic phosphate ester compound of formula (IIa).

Examples of the acidic phosphorous acid ester compound of the formula (IIb) include mono (di) -2-ethylhexyl hydrogenphosphite, mono (di) -decylhydrogenphosphite, mono (Di) -laurylhydrogenphosphite), mono (di) -octadecylhydrogenphosphite (mono (di) -stearylhydrogenphosphite), mono (Mono (di) -oleylhydrogenphosphite), mono (di) -phenylhydrogenphosphite, and the like.

In the present invention, as the component (C), the acidic phosphate ester compound (c-1) may be used singly or in combination of two or more. The acidic phosphorous acid ester compound (c-2) may be used singly or in combination of two or more. The at least one acidic phosphate ester compound (c-1) and at least one acidic phosphorous acid ester compound (c-2) may be used in combination. The amount of the component (C) is 0.005 to 5 mass%, preferably 0.01 to 3 mass%, and more preferably 0.02 to 2 mass%, based on the total amount of the composition. It is more preferable that the mass ratio of (B) / (C) is in the range of 0.1 to 4.0, more preferably in the range of 0.5 to 3.0 in view of the blending amount of the component (B). (B) / (C) has a mass ratio of 0.1 to 4.0, chattering (stick slip) between the cylinder and the rubber (resin) is prevented.

In the hydraulic oil composition of the present invention, at least one member selected from polyhydric alcohol partial esters, alkanolamines, olefin sulfides and dithiocarbamate compounds is used as the lubricity improver for the component (D).

In the polyhydric alcohol partial ester of the component (D), the polyhydric alcohol to be used as the raw material is not particularly limited, but an aliphatic polyol is preferable, and examples thereof include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol , Dihydric alcohols such as tetramethylene glycol and neopentyl glycol, trihydric alcohols such as glycerin, trimethylolethane and trimethylolpropane, diglycerin, triglycerin, pentaerythritol, dipentaerythritol, mannitol and sorbitol Of polyhydric alcohols.

The number of ester bonds in the partial ester may be one or more hydroxyl groups, and there is no particular limitation. The hydrocarbyl group constituting the ester bond is preferably an alkyl group or an alkenyl group having 6 to 20 carbon atoms, and examples thereof include a hexyl group, an octyl group, a decyl group, a dodecyl group, a tetradecyl group, a hexadecyl group, , A hexenyl group, an octenyl group, a decenyl group, a dodecenyl group, a tetradecenyl group, a hexadecenyl group and an octadecenyl group.

Specific examples of the above partial esters of polyhydric alcohols include neopentyl glycol monolaurate, neopentyl glycol monomyristate, neopentyl glycol monopalmitate, neopentyl glycol monostearate, neopentyl glycol monoisostearate, trimethylolpropane mono Trimethylolpropane mono- or di-palmitate, trimethylolpropane mono- or distearate, trimethylolpropane mono- or diisostearate, glycerin mono- or di-laurate, glycerol mono Or distearate, glycerin mono or diisostearate, but are not limited thereto.

The partial ester of the polyhydric alcohol as the component (D) may be used singly or in combination of two or more kinds.

Examples of the sulfurized olefin as the lubricity improver of the component (D) include a compound represented by the formula (III). This compound is obtained by reacting an olefin having 3 to 20 carbon atoms or a 2 to 4-member thereof with a sulfurizing agent such as sulfur or sulfur chloride. As the olefin, propylene, isobutene, diisobutene and the like are preferable.

R ⁵ -S _a -R ₆

(Wherein R ⁵ represents an alkenyl group having 3 to 20 carbon atoms, R ⁶ represents an alkyl group or an alkenyl group having 3 to 20 carbon atoms, and a represents an integer of 1 to 8)

In the present invention, the sulfurized olefin (D) may be used singly or in combination of two or more.

Examples of the alkanolamine in the lubricity improving agent of the component (D) include stearyl monoethanol amine, decyl monoethanol amine, hexyl monopropanol amine, benzyl monoethanol amine, phenyl monoethanol amine, Examples of the amines include monopropanolamine, monoethanolamine, dioleyl monoethanolamine, dilauryl monopropanolamine, dioctyl monoethanolamine, dihexyl monopropanol amine, dibutyl monopropanolamine, oleyl diethanolamine, stearyl Diethanolamine, octyldipropanolamine, butyldiethanolamine, benzyl. Diethanolamine, phenyldiethanolamine, tolyl-dipropanolamine, xylyl diethanolamine, triethanolamine, , Tripropanolamine and the like, and disubstituted amines having 4 to 60 carbon atoms.

These alkanolamines may be used singly or in combination of two or more.

Examples of the thiocarbamate compound in the lubricity improver of the component (D) include methylenebisdibutyldithiocarbamate, methylenebisdiodecyldithiocarbamate, methylenebistridecyldithiocarbamate, and the like. . These thiocarbamate compounds may be used singly or in combination of two or more.

In the hydraulic operating oil composition of the present invention, as the lubricity improving agent for the component (D), one kind of a polyhydric alcohol partial ester, an alkanolamine, an olefin sulfide and a dithiocarbamate compound may be used, It is possible. The amount of the component (D) is selected in the range of 0.005 to 5% by mass based on the total amount of the composition. When the blending amount is less than 0.005 mass%, it is difficult to sufficiently exhibit the effects of reduction of friction in the hydraulic pump sliding portion, reduction of friction between the rubber material and metal in the actuator installed in the hydraulic system, and improvement of wear resistance. On the other hand, if it is more than 5% by mass, the production of sludge increases or the water separability becomes worse. The preferred amount of the lubricity improver for the component (D) is 0.01 to 5% by mass, more preferably 0.03 to 3% by mass, and still more preferably 0.05 to 2% by mass.

In the hydraulic oil composition of the present invention, at least one selected from an amine salt of an acidic phosphate ester and a phosphoric acid triester compound may be blended as the lubricity improver (E), if necessary. Thereby, the effect of the lubricity improver may be further enhanced.

The amine salt of the acid phosphate can be an amine salt of the acid phosphate represented by the formula (IIa). As the amine compound constituting the amine salt, mono-substituted amine, disubstituted amine and tri-substituted amine having 4 to 60 carbon atoms can be used.

Examples of the mono-substituted amine include butylamine, pentylamine, hexylamine, cyclohexylamine, octylamine, laurylamine, stearylamine, oleylamine and benzylamine. Examples of the disubstituted amine include dibutylamine, Examples of the tri-substituted amine include tributylamine, tripentylamine, dibutylamine, dibutylamine, dibutylamine, dibutylamine, dibutylamine, Amine, trihexylamine, tricyclohexylamine, trioctylamine, trilaurylamine, tristearylamine, trioleylamine, tribenzylamine, and the like. Also, it is also possible to use alkanolamines such as stearyl monoethanol amine, decyl monoethanol amine, hexyl monopropanol amine, benzyl monoethanol amine, phenyl monoethanol amine, tolyl monopropanolamine, dioleyl monoethanol Amine, diureyl monopropanol amine, dioctyl monoethanol amine, dihexyl monopropanol amine, dibutyl monopropanol amine, oleyl diethanol amine, stearyl dipropanolamine, lauryl diethanolamine , Octyl · dipropanolamine, butyl · diethanolamine, benzyl · diethanolamine, phenyl · diethanolamine, tolyl · dipropanolamine, xylyl · diethanolamine, triethanolamine and tripropanolamine.

These amine compounds may be used alone or in combination of two or more.

The phosphoric acid triester compound is a compound represented by the general formula (IV), and examples thereof include triaryl phosphate, trialkyl phosphate, trialkyl aryl phosphate, triaryl alkyl phosphate, trialkenyl phosphate and the like. Examples thereof include triphenyl phosphate, (Ethylphenyl) phenylphosphate, di (ethylphenyl) phenylphosphate, ethyldiphenylphosphate, tributylphosphate, ethyldibutylphosphate, cresyldiphenylphosphate, dicresylphenylphosphate, ethylphenyldiphenylphosphate, di (Butylphenyl) phenylphosphate, tributylphenylphosphate, trihexylphosphate, tri (2-ethylhexyl) phenylphosphine, di (propylphenyl) phenylphosphate, triethylphenylphosphate, tripropylphenylphosphate, butylphenyldiphenylphosphate, ) Phosphate, tridecyl phosphate, triazole Phosphate, and the like tree myristyl phosphate, tri palmityl phosphate, tri-stearyl phosphate, tri-oleyl phosphate.

(IV)

[Wherein R ⁷ to R ⁹ are the same as R ² in the formula (II)

As the lubricity improving agent (E) which can be incorporated in the present invention as required, one type of the amine salt of the acidic phosphate ester may be used, or two or more kinds of the amine salts may be used in combination. The phosphoric acid triester compounds may be used singly or in combination of two or more. In addition, at least one amine salt of an acidic phosphate ester and at least one phosphoric acid triester compound may be used in combination. The blending amount of the component (E) is usually selected in the range of 0.005 to 5 mass%, more preferably 0.01 to 5 mass%, and still more preferably 0.02 to 2 mass%, based on the total amount of the composition.

In the hydraulic oil of the present invention, a clean dispersant may be added if necessary.

As the clean dispersant, an ashless clean dispersant and / or a metal cleaner can be used.

Examples of the ashless clean dispersant include succinic acid imides, boron-containing succinic acid imides, benzylamines, and boron-containing benzylamines.

Examples of the metal cleaner include neutral, basic or overbased metal sulfonates, metal phenates, metal salicylates, and metal phosphonates. These ashless cleaners and metal detergents may be used singly or in combination of two or more. The above-described clean dispersant is usually about 0.01 to 1% by mass based on the total amount of the composition.

The hydraulic oil composition of the present invention may contain an antioxidant, a rust inhibitor, a metal deactivator, a pour point depressant, a defoaming agent, an anti-emulsifier and the like within the range not impairing the object of the present invention.

As the antioxidant, a phenol-based antioxidant or an amine-based antioxidant can be preferably used.

The phenolic antioxidant is not particularly limited and any of the known phenolic antioxidants conventionally used as antioxidants for lubricating oils can be appropriately selected and used. Examples of the phenol-based antioxidant include 2,6-di-tert-butyl-4-methylphenol; 2,6-di-tert-butyl-4-ethylphenol; 2,4,6-tri-tert-butylphenol; 2,6-di-tert-butyl-4-hydroxymethylphenol; 2,6-di-tert-butylphenol; 2,4-dimethyl-6-tert-butylphenol; 2,6-di-tert-butyl-4- (N, N-dimethylaminomethyl) phenol; 2,6-di-tert-amyl-4-methylphenol; (4-hydroxy-3,5-di-tert-butylphenyl) propionate, ; 4,4'-isopropylidenebis (2,6-di-tert-butylphenol); 2,2'-methylenebis (4-methyl-6-tert-butylphenol); 4,4'-bis (2,6-di-tert-butylphenol); 4,4'-bis (2-methyl-6-tert-butylphenol); 2,2'-methylenebis (4-ethyl-6-tert-butylphenol); 4,4'-butylidenebis (3-methyl-6-tert-butylphenol); 2,2'-thiobis (4-methyl-6-tert-butylphenol); And polycyclic phenols such as 4,4'-thiobis (3-methyl-6-tert-butylphenol). Of these, monocyclic phenols are preferred from the standpoint of effectiveness.

The amine-based antioxidant is not particularly limited and any of the known amine-based antioxidants conventionally used as antioxidants for lubricating oils can be appropriately selected and used. Examples of the amine-based antioxidant include diphenylamine-based ones, specifically, diphenylamine and mono-octyldiphenylamine; Monononyldiphenylamine; 4,4'-dibutyl diphenylamine; 4,4'-dioctyldiphenylamine;4,4'-dioctyldiphenylamine;4,4'-dinonyldiphenylamine; Tetrabutyl diphenylamine; Tetrahexyldiphenylamine; Tetraoctyldiphenylamine; Alkylated diphenylamines having an alkyl group having 3 to 20 carbon atoms such as tetrahexyldiphenylamine, and naphthylamine-based ones, specifically? -Naphthylamine; Phenyl-α-naphthylamine, and also butylphenyl-α-naphthylamine; Hexylphenyl -? - naphthylamine; Octylphenyl -? - naphthylamine; Naphthylamine and alkyl-substituted phenyl- alpha -naphthylamine having 3 to 20 carbon atoms such as nonylphenyl- alpha -naphthylamine. Among them, a diphenylamine type is preferable to a naphthylamine type in view of the effect, and particularly an alkylated diphenylamine having an alkyl group having 3 to 20 carbon atoms, especially 4,4'-di (C ₃ to C ₂₀ alkyl) Diphenylamine is preferred.

In the present invention, the phenolic antioxidants may be used alone or in combination of two or more. The amine antioxidants may be used singly or in combination of two or more. It is also possible to use at least one phenol-based antioxidant and at least one amine-based antioxidant in combination.

In the present invention, the compounding amount of the antioxidant is usually 0.05 to 2.0% by mass, preferably 0.1 to 1% by mass, based on the total amount of the composition, from the viewpoints of oxidation stability and other physical properties.

Examples of the rust preventing agent include metal sulfonates and succinic acid esters. The amount of these rust preventives to be added is usually about 0.01 to 5% by mass, preferably 0.03 to 1% by mass, based on the total amount of the composition, from the viewpoint of compounding effect and other physical properties.

Examples of the metal deactivator include benzotriazole and thiadiazole. The preferable amount of these metal deactivating agents is generally 0.005 to 1% by mass, preferably 0.007 to 0.5% by mass, based on the total amount of the composition, from the viewpoint of compounding effect and other physical properties.

As the pour point depressing agent, polymethacrylate having a weight average molecular weight of about 50,000 to 150,000 may be used. The blending amount of the pour point depressant is usually 0.1 to 5% by mass, preferably 0.2 to 2% by mass, based on the total amount of the composition, from the viewpoint of compounding effect and other physical properties.

As the antifoaming agent, a polymeric silicone antifoaming agent is preferable, and by blending this antifoaming agent of silicone polymer, the antifoaming property is effectively exhibited.

Examples of the polymeric silicone antifoaming agents include organopolysiloxanes, and fluorine-containing organopolysiloxanes such as trifluoropropylmethyl silicone oil are particularly preferred. This polymeric silicone antifoaming agent is preferably blended in an amount of 0.0001 to 0.5 mass%, preferably 0.0005 to 0.3 mass%, based on the total amount of the composition, from the viewpoint of balancing the defoaming effect and economical efficiency.

Examples of the anti-emulsifier include conventionally known surfactants such as anionic surfactants such as sulfuric acid ester salts and petroleum sulfonic acid salts of castor oil, cationic surfactants such as quaternary ammonium salts and imidazoline type surfactants such as ethylene oxide, Condensation products of the seeds having a molecular weight of about 1500 to 10,000, specifically, polyoxyalkylene polyglycols and esters of dicarboxylic acids thereof, alkylene oxide adducts of alkylphenol-formaldehyde polycondensates, and the like.

As described above, the present invention is a hydraulic oil composition comprising a specific base oil, components (A) to (D), and a combination of these components and component (E), and usually contains a specific base oil and components (A) to And a hydraulic fluid composition comprising these components and component (E).

The hydraulic oil composition of the present invention has good energy saving, heat stability (sludge resistance), abrasion resistance, skirting ability, water separability and friction reduction of the sliding part. Therefore, it is preferably used as a hydraulic operating oil for use in hydraulic equipment such as an injection molding machine, a machine tool, a construction machine, a steel making facility, and the like. However, other hydraulic devices, for example, hydraulic actuators for hydraulic devices such as industrial robots and hydraulic elevators, Performance.

Next, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

All the characteristics were obtained according to the following methods.

(1) Characteristics of base oil

· Sulfur: Measured according to JIS K 2541.

Saturation: Measured in accordance with ASTM D 2007.

Absolute viscosity at 40 占 폚: Calculated from the kinematic viscosity and density at 40 占 폚 measured in accordance with JIS K 2283.

Viscosity index: Measured according to JIS K 2283.

(2) Performance of hydraulic oil composition

(A) High-pressure vane pump test

As a vane pump, a hydraulic circuit was formed using "TOKIMEC SQP2-12", and the operation was carried out under the conditions of an oil temperature of 60 ° C at a rotation speed of 1200 rpm and a pressure of 17.5 MPa, (kW) and machine efficiency were measured.

(B) Thermal Stability Test

The thermal stability test was conducted for 7 days in an air thermostat at 150 ° C in accordance with the "lubricating oil thermal stability method" prescribed in JIS K 2540, and the sample oil after the test was filtered with a filter to measure the amount of sludge in the sample oil.

(C) Insolubility by FZG gear test

The test was conducted under the conditions of 90 ° C, 1450 rpm, and 15 minutes in accordance with ASTM D 5182-91, and the results were indicated by a scuffing occurrence load stage.

(D) Water separability

A water separability test was carried out at a temperature of 54 占 폚 in accordance with JIS K 2520, and the time (in minutes) for the emulsified layer to reach 3 mL was measured.

(E) Coefficient of Friction

Using a Bowden-type reciprocating friction tester, the friction coefficient μ was measured under the following conditions.

Oil temperature: 25 ℃

Load: 19.6 N

Travel distance: 40 mm

Sliding speed: 60 mm / min

Number of sliding: 5 round trip

Friction material: Upper rubber material (U-801, manufactured by NOK)

A lower chromium-plated steel sheet (50 x 100 x 1 mm, manufactured by Testpieces Co., Ltd.)

The types of each component used in the production of the hydraulic oil composition are as follows.

(1) Base oil-1: paraffinic hydrotreated mineral oil corresponding to API classification group III, 0.01 mass% or less of sulfur, 99 mass% of saturation, viscosity index 121, absolute viscosity of 29.21 mPa · s

(2) Base oil-2: hydrotreated paraffinic mineral oil, 0.01 mass% or less of sulfur content, 98 mass% of saturated fraction, viscosity index of 118, absolute viscosity at 40 占 폚 of 34.96 mPa 占 퐏

(3) Viscosity index improver: Polymethacrylate having a weight average molecular weight of 37000

(4) Acid amide compound: A condensate of isostearic acid and tetraethylenepentamine

(5) Acid phosphate ester-1: oleyl acid phosphate

(6) Acidic phosphate ester-2: di (2-ethylhexyl) phosphate

(7) Acid phosphorous acid ester-1: oleylhydrogenphosphite

(8) Alkanolamine: N-alkyldiethanolamine

(9) Fatty acid glyceride: Glyceride oleate (60% by mass monoester, 20% by mass diacetate, 20% by mass triacetate)

(10) Sulfurized olefin: Sulfurized butene

(11) Thiocarbamate: Methylenebis (dibutyldithiocarbamate)

(12) Acid phosphate ester amine salt: mono (di) -methyl acid phosphate dodecylamine salt

(13) Phosphoric acid triester: Tricresyl phosphate

(14) Antioxidant: 2,6-di-tert-butyl-4-methylphenol

(15) Rust inhibitor: alkenylsuccinic acid polyhydric alcohol ester

(16) Metal deactivator: benzotriazole-based deactivator

(17) Anti-emulsifier: polyoxyethylene polyoxypropylene glycol

(18) Antifoaming agent: Polymethacrylate antifoaming agent

Examples 1 to 3, Reference Example 1, and Comparative Example 1

Each hydraulic oil composition having the composition shown in Table 1 was prepared, and the performance was evaluated for each. The results are shown in Table 1.

In Comparative Example 1, a Zn-based commercial oil (hydraulic operating oil) having a viscosity index of 108 was used.

From Table 1, the following can be found.

As a result of the high-pressure vane pump test, Examples 1 to 3 and Reference Example 1 both showed excellent power consumption and mechanical efficiency. As a result of the FZG test, Examples 1 to 3 and Reference Example 1 satisfied 10 stages or more of the ISO standard. As a result of the thermal stability, in Examples 1 to 3 and Reference Example 1, the precipitation amount of the sludge is significantly smaller than that of the Zn-based market oil of Comparative Example 1. [ As a result of the water separability test, it was confirmed that Examples 1 to 3 and Reference Example 1 can maintain good water separability. As a result of the Bowden test, the friction coefficients of the rubber materials in Examples 1 to 3 and Reference Example 1 were all reduced.

INDUSTRIAL APPLICABILITY The hydraulic oil composition of the present invention has excellent energy saving properties, heat stability (sludge resistance), abrasion resistance, abrasion resistance (skirting resistance), water separability and friction reducing property of sliding parts, Field, industrial machinery field, and the like.

Claims (5)

A base oil containing mineral oil having a sulfur content of less than 0.03 mass%, a saturated fraction of 90 mass% or more, a viscosity index of 80 to 121 and an absolute viscosity of 1 to 1000 mPa 占 퐏 at 40 占 폚, (A) 1 to 20% by mass of a polymethacrylate-based viscosity index improver having a weight average molecular weight of 10,000 to 50,000 and (B) a condensation reaction product of a fatty acid having 8 to 24 carbon atoms with a polyethylene polyamine represented by the following general formula (I): 0.005 to 3 mass% (C) from 0.005 to 2% by mass of (c-1) an acidic phosphate ester compound represented by the formula (IIa) and / or (c-2) an acidic phosphorous acid ester compound represented by the formula (D) 0.005 to 5% by mass of at least one selected from a polyhydric alcohol ester, an alkanolamine, an olefin sulfide and a thiocarbamate compound, and (E-1) an amine salt of an acidic phosphate ester compound and (e-2) a phosphoric acid triester compound represented by the general formula (IV) 2% by mass, Wherein the mass ratio of [component (B) / component (C)] is 0.1 to 4.0. (I) H ₂ N (CH ₂ CH ₂ NH) _n H (Wherein n represents the number of the average value of 2 to 6) <Formula IIa>

(Wherein R ¹ represents a hydrogen atom or a hydrocarbon group of 1 to 18 carbon atoms and R ² represents a hydrocarbon group of 1 to 18 carbon atoms) <Formula IIb>

(Wherein R ³ represents a hydrogen atom or a hydrocarbon group of 1 to 18 carbon atoms and R ⁴ represents a hydrocarbon group of 1 to 18 carbon atoms) (IV)

(Wherein R ⁷ to R ⁹ each independently represent a hydrocarbon group of 1 to 18 carbon atoms) The hydraulic fluid composition according to claim 1, wherein the fatty acid having 8 to 24 carbon atoms is isostearic acid. The hydraulic oil composition according to claim 1 or 2, wherein the polyethylene polyamine is any one selected from ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, and hexaethyleneheptamine. . The hydraulic fluid composition according to claim 1 or 2, wherein the component (D) is a fatty acid glyceride. The hydraulic fluid composition according to claim 1 or 2, wherein (e-2) the phosphoric acid triester compound represented by the general formula (IV) is tricresyl phosphate.