JP6512684B2 - Industrial hydraulic oil composition - Google Patents

Description

  INDUSTRIAL APPLICABILITY The present invention has excellent wear resistance to a hydraulic pump, is excellent in sludge generation suppressing effect, has good anti-emulsifiability, and is an industrial hydraulic pressure used for hydraulic equipment such as construction machines, injection molding machines and presses. It relates to a hydraulic oil composition.

  As industrial hydraulic equipment such as construction machines, injection molding machines, and presses become higher in speed, higher in pressure, and smaller in size, the machine elements of these industrial hydraulic equipment are operated under severe conditions. ing. Under such circumstances, the lubricating oil used for them, especially hydraulic oil, is not affected by the performance of the machine even if used for a long time under high pressure, high temperature, high speed and high load. It is required to have sufficient abrasion resistance and thermal oxidation stability. Correspondingly, anti-wear hydraulic fluid containing zinc dialkyl dithiophosphate (hereinafter sometimes referred to as ZnDTP) has been used conventionally. However, ZnDTP is susceptible to degradation due to thermal oxidation and to hydrolysis when it is mixed with water, so it tends to cause sludge. When sludge is generated in the hydraulic circuit, it adheres to various filter parts such as suction filter and line filter, various control valves such as direction control valve and relief valve, piping and tank, etc., causing malfunction of hydraulic equipment There is a case. Therefore, in the industrial oil hydraulic fluid with wear resistance that contains ZnDTP, it is required to suppress the formation of sludge due to thermal oxidation deterioration and to have the ability to quickly separate water when it is mixed with water.

  As industrial hydraulic fluid containing ZnDTP, a metal based detergent such as Ca salicylate is blended to suppress sludge (Patent Document 1), and an aryl phosphite is blended to suppress sludge (patent document 1) 2) The thing etc. which mix | blended phosphate ester amine salt etc. and suppressed the sludge (patent document 3) etc. are known.

Unexamined-Japanese-Patent No. 5-311187 Unexamined-Japanese-Patent No. 10-17882 Unexamined-Japanese-Patent No. 2000-219889

  As mentioned above, ZnDTP has the concern of becoming sludge by thermal oxidation, and there is also the concern of becoming sludge by hydrolysis as well, but since ZnDTP functions as both a load capacity additive and an antioxidant, it is industrial It is a very useful additive in hydraulic fluid.

  Then, although the method of mix | blending the additive which suppresses the above sludges is taken, it is not enough from the viewpoint of long life property and the sludge suppression at the time of water mixing until now. In addition, methods have been considered in which the compounding amount of ZnDTP is reduced within the range that does not impair the abrasion resistance and the performance is compensated by other additives, but in that case, the viewpoint of sufficiently securing the abrasion resistance of the hydraulic pump It was not enough. In particular, in industrial hydraulic fluids formulated with ZnDTP, the results may differ significantly in the wear tests of hydraulic pumps, even though the most common shell 4-ball testers that evaluate the wear resistance do not make a difference There has been a demand for industrial hydraulic fluids having good wear resistance in actual hydraulic pumps.

  Therefore, while the object of the present invention is to reduce the blending amount of ZnDTP, which is a load-bearing additive-antioxidant, the thermal oxidation stability, the sludge generation suppressing effect, the anti-emulsion property and the wear resistance of the hydraulic pump To provide a good industrial hydraulic fluid.

  As a result of intensive investigations in view of the above problems, the present inventors are made to contain a specific amount of ZnDTP of a specific structure, an overbased metal phenate, and a phosphorous acid ester, and contain zinc and phosphorus / zinc in the composition. By making ratio into a specific range, it discovered that thermal hydraulic stability, sludge generation | occurence | production suppression property, anti-emulsion property, and the abrasion resistance of a hydraulic pump were favorable, and found out that industrial hydraulic fluid was obtained, and completed this invention.

That is, the present invention provides (A) a base oil,
(B) 0.01 to 0.5% by mass of primary dialkyl dithiophosphate zinc,
(C) 0.03 to 1% by mass of an overbased metal phenate having a base number of 150 to 400 mg KOH / g ,
(D) 0.005 to 0.1% by mass of phosphite ester,
Contains
The content of zinc in the composition is 100 to 500 mass ppm,
The mass ratio of phosphorus content / zinc content in the composition is 0.75 to 2.0,
And providing an industrial hydraulic fluid composition characterized by

  According to the present invention, it is possible to provide an industrial hydraulic oil composition having excellent abrasion resistance, thermal oxidation stability, anti-sludge generation and anti-emulsification properties of a hydraulic pump while reducing the compounding amount of ZnDTP. it can. Therefore, the hydraulic fluid composition of the present invention is suitably used as industrial hydraulic fluid in various industrial hydraulic devices such as construction machines, injection molding machines and presses.

  The industrial hydraulic oil composition of the present invention comprises (A) a base oil, (B) 0.01 to 0.5% by mass of a primary dialkyl dithiophosphate zinc, (C) an overbased metal phenate of 0. 2%. A composition comprising 03 to 1% by mass and (D) a phosphite ester of 0.005 to 0.1% by mass, and the content of zinc in the composition is 100 to 500 mass ppm, It is an industrial hydraulic fluid composition characterized in that the mass ratio of phosphorus content to zinc content in the inside is 0.75 to 2.0.

  The (A) base oil contained in the industrial hydraulic oil composition of the present invention refers to the base oil portion of the hydraulic oil composition, and a base oil comprising a base oil component of one kind of mineral oil, 2 Mixed base oil consisting of various types of mineral oil base oil components, Base oil consisting of one kind of synthetic base oil component, mixed base oil consisting of two or more kinds of synthetic base oil components, or one or more kinds of mineral oil base A mixed base oil comprising an oil component and one or more synthetic base oil components. The base oil (A) is not particularly limited as long as it is a base oil generally used as a hydraulic fluid.

The kinematic viscosity of the base oil (A) at 40 ° C. measured by JIS K 2283 “Kinematic viscosity test method” is preferably 15 to 110 mm ² / s, more preferably 20 to 90 mm ² / s, and particularly preferably 28 to 28 It is 75 mm ² / s. In the present invention, the kinematic viscosity of the (A) base oil refers to the kinematic viscosity of the mixed base oil after mixing when two or more different base oil components are mixed. (A) When the kinematic viscosity of the base oil at 40 ° C. is in the above range, it is easy to ensure load-bearing capacity, and it is easy to suppress the decrease in volumetric efficiency of the pump, even when used for high pressure hydraulic equipment of 10 MPa or more The oil film can be easily held, the influence on the wear resistance can be suppressed, and the mechanical efficiency of the hydraulic device can be easily maintained in an appropriate range.

  (A) It is preferable that% CP in the ASTM D3238 “nd M ring analysis method” of base oil is 55 to 92,% CN is 8 to 40, and% CA is 10 or less, and% CP is 60 to 90 It is more preferable that% CN is 10 to 35 and% CA is 7 or less. When the% CP,% CN and% CA of the (A) base oil are in the above ranges, the thermal oxidation stability becomes high and it becomes easy to suppress the generation of sludge. In addition, when the% CP and% CN of the (A) base oil are in the above ranges, the solubility of various additives including (B) ZnDTP contained in the industrial hydraulic fluid composition can be easily ensured. .

  The viscosity index of the (A) base oil is preferably 95 or more, more preferably 98 or more. When the viscosity index of the base oil (A) is in the above range, the degree of purification of the base oil is increased, the thermal oxidation stability is increased, and the generation of sludge is easily suppressed.

  The aniline point in JIS K 2256 “Aniline point test method” of the base oil (A) is preferably 90 to 140 ° C., more preferably 95 to 130 ° C. (A) When the aniline point of the base oil is in the above range, the degree of purification of the base oil is increased, the thermal oxidation stability is increased, the generation of sludge is easily suppressed, and the solubility of the additive is easily ensured. , It becomes easy to ensure seal material compatibility.

  The base oil component constituting the base oil (A) is not particularly limited, and may be a mineral base oil component or a synthetic base oil component.

  As mineral oil base oil components, solvent refined mineral oil, hydrorefined mineral oil, hydrocracked mineral oil and the like can be mentioned. Among these, hydrorefined mineral oil and hydrocracked mineral oil are preferable. Although the manufacturing method of a hydrorefined mineral oil and a hydrocracked mineral oil is not specifically limited, As the preferable manufacturing method, the following method is mentioned. As a preferable method for producing a hydrorefined mineral oil, a method of subjecting a fraction obtained as a lubricating oil fraction to solvent extraction, hydrorefining and solvent dewaxing after vacuum distillation of a residue oil obtained by atmospheric distillation And then the method of performing the second hydrorefining. As a preferred method for producing hydrocracked mineral oil, first, the residual oil obtained by atmospheric distillation of crude oil is treated with a vacuum distillation apparatus, the vacuum gas oil obtained there is subjected to hydrotreating and hydrocracking, and thereafter The residue obtained by removing light components and fuel components with a vacuum stripper is obtained, and the residue is distilled under reduced pressure, and the resulting lubricating oil fraction is subjected to hydrodewaxing treatment or wax isomerization treatment to perform stabilization treatment In this case, a method of increasing viscosity index by wax isomerization is mentioned as a more preferable method. Furthermore, base oils obtained by hydrocracking treatment and hydroisomerization treatment of raw materials such as slack wax by solvent dewaxing are also included.

  Base oils obtained by subjecting raw materials such as waxes obtained by Fischer-Tropsch synthesis to hydrocracking treatment and hydroisomerization treatment as synthetic base oil components, poly α-olefin base oils, alkyl benzenes, alkyl naphthalenes, etc. Synthetic base oils such as aromatic synthetic oils, ester oils, alkylated phenyl ether oils, polyalkylene glycols and the like can be mentioned. As a suitable method for producing a poly-α-olefin base oil, an α-olefin having 6 to 18 carbon atoms is synthesized by low polymerization of ethylene or thermal decomposition of a wax, and 2 to 9 units of this α-olefin are polymerized and hydrogenated. The method of performing reaction is mentioned.

  Preferred examples of ester oils are diesters produced from monohydric alcohols and dicarboxylic acids, polyol esters produced from polyols and monocarboxylic acids, or polyols, monocarboxylic acids and polycarboxylic acids Complex ester etc. are mentioned. Examples of diesters include esters of dibasic acids such as adipic acid, azelaic acid, sebacic acid and dodecanedioic acid. As a dibasic acid, a C4-C36 aliphatic dibasic acid is preferable. The alcohol residue constituting the ester portion is preferably a monohydric alcohol residue having 4 to 26 carbon atoms. Moreover, specifically as a polyol used for a polyol ester or complex ester, the hindered alcohol which does not have (beta) hydrogen, such as trimethylolpropane, pentaerythritol, neopentyl glycol, is used suitably. Also, as monocarboxylic acids used for polyol esters and complex esters, straight chain saturated fatty acids such as coconut fatty acid, stearic acid, linear unsaturated fatty acids such as oleic acid, branched fatty acids such as isostearic acid, etc. are suitably used. As polycarboxylic acids, linear saturated polycarboxylic acids such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid and the like are suitably used. Preferred examples of the alkylated phenyl ether oil include alkylated diphenyl ether and (alkylated) polyphenyl ether. In addition, polyalkylene glycols include polyethylene glycol, polypropylene glycol, polybutylene glycol, or ethylene oxide-propylene oxide copolymer, propylene oxide-butylene oxide copolymer, and derivatives of these.

  In addition, as a base oil component used for (A) base oil, hydroisomerized base oil obtained from raw materials such as slack wax obtained by solvent dewaxing and wax obtained by Fischer-Tropsch synthesis, and aromatic hydrocarbon oil It is more preferable to use a mixture of solvent refined mineral oil, hydrorefined mineral oil, hydrocracked mineral oil and the like in order to adjust% CP and% CN to an appropriate range.

  The content of the (A) base oil (base oil portion) of the industrial hydraulic fluid composition of the present invention is preferably 90 to 99.8% by mass based on the total amount of the industrial hydraulic fluid composition. More preferably, it is 92 to 99.7% by mass, and particularly preferably 95 to 99.5% by mass.

The industrial hydraulic oil composition of the present invention contains (B) a primary dialkyl dithiophosphate zinc. (B) The primary dialkyl dithiophosphate zinc is a dialkyl dithiophosphate zinc wherein the alkyl group in the zinc dialkyl dithiophosphate is a primary alkyl group, and is represented by the following general formula (1).
General formula (1):

Each of R ^{1 to} R ⁴ in the general formula (1) is a primary alkyl group and preferably has 2 to 18 carbon atoms, more preferably 4 to 16 carbon atoms, and 6 to 12 carbon atoms. Is particularly preferred. In addition, with a primary alkyl group, general formula (3):
R ⁸ -CH _2- (3)
(In the formula, R ⁸ is a linear or branched alkyl group, and the carbon number is preferably 1 to 17, more preferably 3 to 15, and particularly preferably 5 to 11.)
It is an alkyl group represented by That is, the carbon bonded to the O atom is an alkyl group which is a primary carbon. If any one of R ^{1 to} R ⁴ is a secondary alkyl group (R ⁹ R ¹⁰ (CH)-(R ⁹ and R ¹⁰ is a linear or branched alkyl group)), thermal oxidation occurs The stability is poor and sludge is likely to be generated.

As a primary alkyl group of R ^{1 to} R ⁴ , methyl group, ethyl group, propyl group, butyl group, isobutyl group, pentyl group, hexyl group, heptyl group, octyl group, ethylhexyl group, nonyl group, decyl group, undecyl group And dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl and the like.

  In the hydraulic oil composition of the present invention, the content of (B) primary dialkyl dithiophosphate zinc is 0.01 to 0.5 mass%, preferably 0.05 to 0.4 mass%, 0.1 -0.4 mass% is the most preferable. The primary dialkyl dithiophosphate zinc is used as an antiwear agent and an antioxidant, and if the content of the (B) primary dialkyl dithiophosphate zinc is less than the above range, the abrasion resistance and the antioxidant property become insufficient. Moreover, when the said range is exceeded, the sludge generation inhibitory effect will become low.

  The industrial hydraulic fluid composition of the present invention contains (C) an overbased metal phenate. (C) Examples of the metal part of the overbased metal phenate include alkaline earth metals, preferably magnesium and calcium, and particularly preferably calcium. Further, the inorganic salt used to impart the overbasing property is preferably magnesium carbonate or calcium carbonate, particularly preferably calcium carbonate. (C) The base number of the overbased metal phenate is preferably 100 to 400 mg KOH / g, and more preferably 150 to 350 mg KOH / g. The calcium content of the (C) overbased metal phenate is preferably 3 to 20% by mass, more preferably 5 to 15% by mass, in terms of Ca atom. (C) Overbased metal phenate suppresses the generation of sludge due to ZnDTP. When the base number or calcium content of the (C) overbased metal phenate is less than the above range, the sludge generation suppressing effect tends to be low, and when the above range is exceeded, the demulsification properties may be deteriorated.

  The content of the (C) overbased metal phenate in the industrial hydraulic oil composition of the present invention is 0.03 to 1% by mass, preferably 0.06 to 0.6% by mass, and 0.08 -0.4% by weight is particularly preferred. (C) Since the overbased metal phenate suppresses the generation of sludge caused by ZnDTP, when the content of the (C) overbased metal phenate is less than the above range, the sludge generation suppressing effect is reduced, and If the above range is exceeded, the demulsibility will be worse.

The industrial hydraulic fluid composition of the present invention contains (D) a phosphite. (D) The phosphite ester is represented by the following general formula (2).
General formula (2):

In the general formula (2), R ⁵ , R ⁶ and R ^{7 each} represent a hydrocarbon group having 1 to 30 carbon atoms, and any of an aliphatic hydrocarbon group, an aromatic hydrocarbon group and an alicyclic hydrocarbon group And may be linear or branched, and may be saturated or unsaturated. When R ⁵ , R ⁶ and R ⁷ are aliphatic or alicyclic hydrocarbon groups, such aliphatic or alicyclic hydrocarbon groups are preferably saturated. When R ⁵ , R ⁶ and R ⁷ are aromatic hydrocarbon groups, the carbon number of such aromatic hydrocarbon groups is preferably 6 to 30, more preferably 7 to 24. It is preferably 8 to 20, and more preferably 8 to 18. When R ⁵ , R ⁶ and R ⁷ are aromatic hydrocarbon groups, such aromatic hydrocarbon groups are preferably monocyclic aromatic hydrocarbon groups. R ⁵ , R ⁶ and R ⁷ may be the same or different.

  In the industrial hydraulic oil composition of the present invention, the content of (D) phosphite ester is 0.005 to 0.1% by mass, and preferably 0.008 to 0.08% by mass. And 0.01 to 0.06% by mass is particularly preferable. (D) If the content of the phosphite ester is less than the above range, the anti-abrasion property, particularly the anti-abrasive property of the actual hydraulic pump becomes low, and the phosphite ester functions as an antioxidant When the above range is exceeded, dissolution is difficult and there is a possibility that sludge may be generated.

  In the industrial hydraulic fluid composition of the present invention, the content of zinc (atom) is 100 to 500 mass ppm, preferably 250 to 480 mass ppm, and more preferably 320 to 470 mass ppm. If the content of the zinc content in the composition is less than the above range, the abrasion resistance becomes low, and if it exceeds the above range, sludge tends to be generated.

  In the industrial hydraulic oil composition of the present invention, the mass ratio of phosphorus content (atoms) / zinc content (atoms) is 0.75 to 2.0, and further 0.8 to 1.5. preferable. If the mass ratio of phosphorus content / zinc content in the composition is less than the above range, the abrasion resistance of the hydraulic pump becomes low, and if it exceeds the above range, sludge tends to be generated or the anti-emulsion property Becomes lower.

  The mass ratio of calcium component (atom) to zinc component (atom) in the industrial hydraulic oil composition of the present invention is preferably 0.2 to 1.5, and is 0.25 to 1.0. Is more preferred. When the mass ratio of calcium content to zinc content in the composition is in the above range, the sludge generation suppressing effect is easily obtained, and the demulsification property is improved.

  The industrial hydraulic oil composition of the present invention may further contain neutral calcium sulfonate having a base number of 50 mg KOH / g or less. The industrial hydraulic oil composition of the present invention is preferable in that it contains a neutral calcium sulfonate having a base value of 50 mg KOH / g or less, in that the antirust property or the anti-emulsion property is enhanced. When the base number of neutral calcium sulfonate exceeds 50 mg KOH / g, it becomes easier to emulsify when mixed with water, or the effect of improving the rust resistance is not seen, so the base number of neutral calcium sulfonate is 50 mg KOH / g or less preferable. The content of neutral calcium sulfonate of 50 mg KOH / g or less in the industrial hydraulic fluid composition of the present invention is preferably 0.03 to 0.9 mass%, and 0.1 to 0.5 mass%. It is more preferable that When the content of the neutral calcium sulfonate of 50 mg KOH / g or less is within the above range, the antirust property or the anti-emulsifying property is enhanced. In addition, since 50 mg KOH / g or less of neutral calcium sulfonate is a calcium source in industrial hydraulic oil composition, the industrial hydraulic oil composition of the present invention contains neutral calcium sulfonate of 50 mg KOH / g or less In the above case, calcium content includes calcium content derived from neutral calcium sulfonate not more than 50 mg KOH / g in the calculation of the mass ratio of calcium content / zinc content.

  The industrial hydraulic fluid composition of the present invention can contain various known additives, as needed, as long as the object of the present invention is not impaired. As such additives contained as necessary, for example, antioxidants, antiwear agents, extreme pressure agents, ashless dispersants, rust inhibitors, metal deactivators, pour point depressants, A viscosity index improver, a friction modifier, an antifoamer etc. are mentioned.

  As an antioxidant, a single ring such as 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, etc. Phenolic antioxidant, 4,4'-bis (2,6-di-t-butylphenol), 4,4'-methylenebis (2,6-di-t-butylphenol), 4,4'-ethylenebis ( 2,6-di-tert-butylphenol), 4,4'-butylenebis (2,6-di-tert-butylphenol), 6,6'-methylenebis (2-di-tert-butyl-4-methylphenol), etc. Sulfur-containing antioxidants such as 4,5'-thiobis- (2,6-di-t-butyl-phenol) and 4,4'-thiobis- (2-methyl-6-t-butyl-phenol) Phenolic antioxidant, archi Examples include amine-based antioxidants such as fluorinated diphenylamine and alkylated phenyl-α-naphthylamine, and phosphorus-based antioxidants such as alkyl phosphite and aryl phosphites.

Antiwear agents and extreme pressure agents include sulfurized olefin or sulfur-phosphorus extreme pressure agents such as sulfurized olefins, polysulfides, sulfurized oils and fats, thiophosphoric acids and dithiophosphoric acid derivatives, phosphoric esters, acidic phosphoric acid esters or There may be mentioned phosphorus-based antiwear agents such as amine salts and the like, phosphorus-based extreme pressure agents, and organic metal-based extreme pressure agents such as ZnDTC.
As an ashless type dispersing agent, a succinimide compound is mentioned as an ashless type dispersing agent, Specifically polybutenyl bis succinimide and its boron-modified compound are mentioned.

  As rust inhibitors, metal soaps such as sulfonate metal salts and metal salts of naphthenic acid, alkylsuccinic acid derivatives, alkenylsuccinic acid derivatives, lanolin compounds, surfactants such as sorbitan monooleate and pentaerythritol monooleate, wax and the like Alkyl wax is used such as oxidized wax, petrolatum, N-oleyl sarcosine, rosin amine, alkylated amine compounds such as dodecylamine and octadecylamine, fatty acids such as oleic acid and stearic acid, phosphorus compounds such as phosphite, etc. Acid derivatives, alkenylsuccinic acid derivatives, surfactants, and alkylated amine compounds are preferably used, and alkylsuccinic acid derivatives and alkenylsuccinic acid derivatives are more preferable.

  As metal deactivators, benzotriazole and derivatives thereof, indazole and derivatives thereof, benzimidazole and derivatives thereof, indole and derivatives thereof, thiadiazole and derivatives thereof, etc. are used, and benzotriazole and derivatives thereof, thiadiazole and derivatives thereof Is preferably used.

  Examples of pour point depressants include polyalkyl methacrylates, polybutenes, polyalkyl styrenes, polyvinyl acetates and polyalkyl acrylates.

  Examples of the viscosity index improver include poly (meth) acrylate (hereinafter sometimes referred to as PMA) and olefin copolymer. Examples of poly (meth) acrylates include those having a weight average molecular weight of 30,000 to 200,000 and non-dispersive PMA having no polar group as a monomer and dispersive PMA using a monomer having a polar group It can be mentioned. Moreover, as an olefin copolymer, the thing of the weight average molecular weights 5000-100000 is mentioned, and if it is a copolymer of an olefin, what kind of thing may be used, for example, the copolymer of ethylene and monomers other than ethylene Can be mentioned.

  Examples of friction modifiers include half esters and / or full ester compounds of polyhydric alcohols, fatty acids, amide compounds, amine compounds, alcohol compounds, phosphoric acid ester compounds, acidic phosphoric acid ester amine salts, etc. Be Specifically, monooleyl glyceryl ester, oleic acid, oleic acid amine salt, oleic acid amide, oleyl amine, stearyl amide, stearyl amine, acidic phosphoric acid ester oleyl amine salt and the like can be mentioned.

  As an antifoamer, silicone type antifoamers, such as dimethyl silicone, an alkyl modified silicone, phenyl modified silicone, fluorine modified silicone, a polyacrylate type antifoamer etc. are mentioned.

40 ° C. The kinematic viscosity of industrial hydraulic fluid composition of the present invention, in the JIS K2283 kinematic viscosity test method, is preferably 9.00~110mm ² / s, in particular to be 18~100mm ² / s preferably, more preferably 25~75mm ² / s, and further preferably from 30 to 60 mm ² / s. The viscosity index of the industrial hydraulic fluid composition of the present invention is not particularly limited, but preferably 100 or more in the JIS K 2283 dynamic viscosity test method. When the viscosity index is in the above range, the fluidity at low temperature is improved, and the oil film retention at high temperature is improved.

  INDUSTRIAL APPLICABILITY The industrial hydraulic fluid composition of the present invention is applied to various industrial hydraulic fluids, but is preferably used particularly as a hydraulic fluid used in a hydraulic system. Furthermore, when the industrial hydraulic fluid composition of the present invention is used as high pressure as 7 MPa or more in the hydraulic system, the case where abrasion resistance is required or the oil temperature becomes high, or If the oil temperature is high due to the small oil tank, or if the hydraulic equipment is exposed to high temperatures in steel-related equipment, etc., or if the amount of hydraulic oil used is large and can not be replaced frequently, etc. It is particularly effective when it is necessary to

  Next, the present invention will be more specifically described by way of examples. The present invention is not limited at all by these examples.

1. Preparation of hydraulic oil composition As Examples 1-2 and Comparative Examples 1-6, industrial hydraulic oil compositions containing the base oils and additives shown below in the proportions shown in Tables 2 and 3 are used. Prepared.
(1) Mixed base oil: A mixed base oil of three base oil components A, B and C described in Table 1, wherein the proportion of the base oil component A is 50% by volume, and the kinematic viscosity at 40 ° C. is It was mixed so as to be 46 mm ² / s.

(2) ZnDTP: primary dialkyl dithiophosphate zinc wherein R ^{1 to} R ⁴ in the general formula (1) is 2-ethylhexyl group (3) overbased Ca phenate: base number by the perchloric acid method is 255 mg KOH / g, Ca Containing 9.2%.
(4) Phosphorous acid ester: those in which each of R ⁵ , R ⁶ and R ⁷ in the general formula (2) is an aromatic hydrocarbon group having 14 carbon atoms having two tertiary butyl groups as a substituent.
(5) Neutral Ca sulfonate: having a base number of 0.3 mg KOH / g and a Ca content of 2.0% according to the perchloric acid method.
(6) Phenolic antioxidant: 2,6-di-t-butyl-4-methylphenol (7) pour point depressant: polyalkyl methacrylate (8) antifoam: dimethyl silicone

2. Evaluation of hydraulic oil composition The hydraulic oil compositions of Examples 1 to 2 and Comparative Examples 1 to 6 were evaluated by the test methods shown below, and the results are shown in Tables 2 and 3.
(1) Elemental amount Measured by JPI-5S-38 "lubricant-additive element test method-inductively coupled plasma emission spectrometry".
(2) Thermal oxidation stability test 40 ml of a sample is put in a glass container with an inner diameter of 2.5 cm, the catalyst of steel and copper shown below is immersed and left in a thermostatic chamber with a rotating disc at 140 ° C. for 240 hours Sludge amount (using 0.75 μm Millipore filter) was measured (case with “catalyst” in the table).
Catalyst material / size:
Steel = SPCC-SB, Copper = C1100P, size is 1.0 mm x 20 mm x 50 mm
Similarly, the test was conducted under the condition that the steel and copper catalysts were not immersed (case of "no catalyst" in the table).
(3) Demulsification test Based on JISK 2520 "water separation test method 5. Demulsification test method", demulsibility was evaluated and the amount and time of oil layer-water tank-emulsification layer were measured.
(4) TOST
Based on JIS K 2514 "turbine oil oxidation stability test", the acid value change and the amount of sludge after 1000 hours were measured.
(5) Shell 4 ball test According to JPI-5S-32 "Abrasion resistance test method for lubricating oil (shell 4 ball type)", using the test conditions specified in JCMAS P 041, 294 N, 1200 rpm, 60 min, 75 The wear scar diameter at ° C. was measured.
(6) FZG test (load bearing test)
It implemented according to DIN 51354-2 "Mechanical testing by the FZG gear rig method" of German industrial standard using a FZG gear test machine. In other words, load the gear in accordance with the standard, and then test it until it reaches 21,700 rotations at a gear rotation speed of 1,440 rpm (one stage so far), gradually raise the load stage, and The total area width of wear and tear (scuffing and scoring) on the tooth surface was less than 20 mm as a pass, and the rejected stages were described in the table.
(7) Vickers V-104c pump test Based on ASTM D 7043-10 "Standard Test Method for Indicating Wear Characteristics of Non-Petroleum and Petroleum Hydraulic Fluids in a Constant Volume Vane Pump", with an operation time of 500 hours, cam rings and vanes The total amount of wear was evaluated.

＊表中、「残部」とは、全量が１００質量％になるように含有させたことを示す。

* In the table, "remainder" indicates that the total amount is 100% by mass.

＊表中、「残部」とは、全量が１００質量％になるように含有させたことを示す。
１）フィルター閉塞のため測定不可

* In the table, "remainder" indicates that the total amount is 100% by mass.
1) Impossible to measure due to filter blockage

  As shown in Table 2, in Examples 1 and 2 satisfying the constitution of the present invention, the amount of sludge is extremely small in the thermal oxidation stability test, the change in acid value in the TOST test is also small, the amount of sludge is small, and the oxidation stability is excellent. Know that Furthermore, the emulsion layer is 3 ml or less in 20 minutes or less in terms of the demulsibility as well, and the demulsibility is good. In addition, the wear mark in the shell 4 ball test is small, the Fail Lord Stage in the FZG gear test is high with 12 stages, and the extreme pressure property is excellent, and the wear amount in the V-104c vane pump test is extremely small. It turns out that it is very excellent in abrasion resistance.

On the other hand, as compared with Examples 1 and 2, Comparative Examples 1 and 2 which do not contain the overbased Ca phenate and do not contain any phosphite, have a very large amount of sludge in the thermal oxidation stability test. Further, in Comparative Example 1, the FZG test fails at 11 stages.
In Comparative Example 3, 0.05% by mass of the overbased Ca phenate is contained with respect to Comparative Example 1, but the amount of sludge in the thermal oxidation stability test is improved because it does not contain a phosphite ester. Not pass, FZG test also fails in 11 stages.
When the amount of the overbased Ca phenate is further increased based on Comparative Example 3, the amount of sludge in the thermal oxidation stability test is improved, but the FZG test is rejected in 11 stages, and the V-104c vane pump test is not performed. The amount of wear is also very high.
Further, in Comparative Example 5 in which the compounding amount of ZnDTP of Comparative Example 4 is increased within the range specified in the present invention, the amount of wear of the V-104c vane pump test is improved, but the wear resistance of hydraulic oil is improved. It is not enough for performance.
Therefore, in Comparative Example 6, when the compounding amount of ZnDTP was further increased to an amount exceeding the amount specified in the present invention than Comparative Example 5, although the wear resistance in the V-104c vane pump test could be sufficiently secured, the TOST test In the above, a large amount of sludge was generated, resulting in poor sludge control in the presence of water.

Claims (3)

(A) base oil,
(B) 0.01 to 0.5% by mass of primary dialkyl dithiophosphate zinc,
(C) 0.03 to 1% by mass of an overbased metal phenate having a base number of 150 to 400 mg KOH / g ,
(D) 0.005 to 0.1% by mass of phosphite ester,
Contains
The content of zinc in the composition is 100 to 500 mass ppm,
The mass ratio of phosphorus content / zinc content in the composition is 0.75 to 2.0,
An industrial hydraulic fluid composition characterized by   The industrial hydraulic oil composition according to claim 1, wherein the mass ratio of calcium to zinc in the composition is 0.2 to 1.5.   The industrial hydraulic oil composition according to any one of claims 1 and 2, wherein the overbased metal phenate is an overbased calcium phenate.