JP2019137749A - Hydraulic oil composition - Google Patents

Abstract

To provide a hydraulic oil composition having a wear prevention effect in a medium load region and an oiliness effect in a small load region, which effects cannot be achieved by a hydraulic oil composition containing a known anti-wear agent such as TCP.SOLUTION: The hydraulic oil composition comprises lubricant base oil and a compound represented by the following general formula (1). [In the formula (1), Rrepresents a monovalent hydrocarbon group, and Rand Reach independently represent a hydrogen atom or an alkyl group.]SELECTED DRAWING: None

Description

  The present invention relates to a hydraulic fluid composition.

  Conventionally, in the field of construction machinery and the like, lubricating oil for hydraulic actuators (hereinafter referred to as “hydraulic hydraulic oil”) has been widely used. In recent years, with the improvement in performance of hydraulic actuators, hydraulic actuators have been operated under a wider load range. Therefore, further improvement in the lubricating performance is required for the hydraulic fluid used in the hydraulic actuator.

  Generally, in order to improve the lubricating performance of a lubricating oil, an additive is blended in the lubricating base oil according to desired characteristics. For example, Patent Literature 1 discloses a hydraulic fluid in which tricresyl phosphate (TCP) or the like is blended as a wear inhibitor in a lubricant base oil.

JP 2003-171684 A

  The hydraulic fluid containing TCP can improve the wear prevention effect to some extent by forming a phosphoric acid coating on the friction surface when the hydraulic actuator is operated in a medium load region. However, as described above, in recent years, hydraulic fluids are required to have load resistance under a wider load range. For example, oil hydraulic effects under a low load range where a phosphate coating is not formed are sufficiently exhibited. I can't do it.

  The present invention has been made in view of such a situation, and cannot be achieved by a hydraulic fluid composition containing a known antiwear agent such as TCP, and has a wear prevention effect in a middle load region and a low load region. It is an object of the present invention to provide a hydraulic fluid composition having an oily effect.

  The present invention provides a hydraulic fluid composition comprising a lubricating base oil and a compound represented by the following general formula (1).

［式（１）中、Ｒ^１は１価の炭化水素基を表し、Ｒ^２及びＲ^３はそれぞれ独立に水素原子又はアルキル基を表す。］

[In Formula (1), R ¹ represents a monovalent hydrocarbon group, and R ² and R ³ each independently represent a hydrogen atom or an alkyl group. ]

  ADVANTAGE OF THE INVENTION According to this invention, the hydraulic fluid composition which has the wear prevention effect in a medium load area | region and the oil-based effect in a low load area | region can be provided.

  The hydraulic fluid composition according to the present embodiment includes a lubricating base oil and a compound represented by the following general formula (1).

In formula (1), R ¹ represents a monovalent hydrocarbon group, and R ² and R ³ each independently represent a hydrogen atom or an alkyl group.

  The lubricating base oil is, for example, mineral oil, synthetic oil, or a mixture of both.

  As mineral oils, lubricating oil fractions obtained by atmospheric distillation and vacuum distillation of crude oil are removed from solvents, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrorefining, sulfuric acid washing, clay. Examples thereof include paraffinic and naphthenic mineral oils, normal paraffins, isoparaffins, and the like, which are purified by combining purification treatments such as treatment alone or in combination of two or more. These mineral oils may be used alone or in any combination of two or more.

Preferred base oils include the following base oils.
(1) Distilled oil obtained by atmospheric distillation of paraffin-based crude oil and / or mixed-base crude oil (2) Vacuum-distilled distilled oil (WVGO) of atmospheric distillation residue oil of paraffin-based crude oil and / or mixed-base crude oil )
(3) Wax obtained by a lubricant dewaxing step and / or a Fischer-Tropsch wax produced by a GTL process or the like (4) One or more mixed oils selected from the above (1) to (3) Mild hydrocracking oil (MHC)
(5) Mixed oil of two or more oils selected from the above (1) to (4) (6) Detachment of (1), (2), (3), (4) or (5) Oil (DAO)
(7) Mild hydrocracking treatment oil (MHC) of (6) above
(8) A mixed oil or the like of two or more kinds of oils selected from the above (1) to (7) is used as a raw oil, and this raw oil and / or a lubricating oil fraction recovered from this raw oil is usually used. Oil obtained by refining by the refining method and recovering the lubricating oil fraction

Here, as a normal refining method, a refining method used in base oil production can be arbitrarily adopted. Examples of normal purification methods include the following purification methods.
(A) Hydrorefining such as hydrocracking, hydrofinishing, etc. (b) Solvent refining such as extraction of furfural solvent (c) Dewaxing such as solvent dewaxing, catalytic dewaxing, etc. Purification (e) Chemical (acid or alkali) purification such as sulfuric acid washing and caustic soda washing These purification methods can be used singly or in combination of two or more and in any order.

  Synthetic oils include, for example, esters, ethers and hydrocarbon oils.

  The ester is preferably an ester of a fatty acid (monobasic acid) and an alcohol and an ester of a polybasic acid and an alcohol, more preferably an ester of a fatty acid and an alcohol.

  The fatty acid may be a saturated fatty acid or an unsaturated fatty acid, and is preferably an unsaturated fatty acid.

  The fatty acid is preferably a fatty acid having 2 to 24 carbon atoms. Specific examples of fatty acids having 2 to 24 carbon atoms include acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, Saturated fatty acids such as tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, icosanoic acid, henicosanoic acid, docosanoic acid, tricosanoic acid, tetracosanoic acid, acrylic acid, butenoic acid, pentenoic acid, hexenoic acid, heptene Acid, octenoic acid, nonenoic acid, decenoic acid, undecenoic acid, dodecenoic acid, tridecenoic acid, tetradecenoic acid, pentadecenoic acid, hexadecenoic acid, heptadecenoic acid, octadecenoic acid, nonadecenoic acid, icosenoic acid, heicosenoic acid, docosenoic acid, tricosenoic acid, Unsaturated fats such as tetracosenoic acid , And the like and mixtures thereof. These fatty acids may be linear or branched.

  Examples of polybasic acids include dibasic acids and tribasic acids. The polybasic acid may or may not have an unsaturated bond. The carbon number of the dibasic acid may be, for example, 2-16. Specific examples of the dibasic acid having 2 to 16 carbon atoms include ethanedioic acid, propanedioic acid, butanedioic acid, pentanedioic acid, hexanedioic acid, heptanedioic acid, octanedioic acid, nonanedioic acid, and decane. Diacid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, heptadecanedioic acid, hexadecanedioic acid, hexenedioic acid, heptenedioic acid, octenedioic acid, nonenedioic acid, decenedioic acid, heptadecenedioic acid , Hexadecenedioic acid and mixtures thereof. These dibasic acids having 2 to 16 carbon atoms may be linear or branched. Examples of the tribasic acid include trimellitic acid.

  The alcohol may be a monohydric alcohol or a polyhydric alcohol. Carbon number of monohydric alcohol becomes like this. Preferably it is 1-24, More preferably, it is 1-12, More preferably, it is 1-8. Specific examples of the alcohol having 1 to 24 carbon atoms include methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, Hexadecanol, heptadecanol, octadecanol, nonadecanol, icosanol, henycosanol, tricosanol, tetracosanol, and mixtures thereof can be mentioned. These monohydric alcohols may be linear or branched.

  The number of hydroxyl groups contained in the polyhydric alcohol (polyol) is preferably 2 to 10, more preferably 2 to 6. Specific examples of the polyhydric alcohol having 2 to 10 hydroxyl groups include ethylene glycol, diethylene glycol, polyethylene glycol (3 to 15 mer of ethylene glycol), propylene glycol, dipropylene glycol, and polypropylene glycol (of propylene glycol). 3 to 15-mer), 1,3-propanediol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,2-propanediol, 2-methyl- Dihydric alcohols such as 1,3-propanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5-pentanediol, neopentyl glycol; glycerin, polyglycerin (glycerin 2 to 8 mer, such as diglycerin Triglycerin, tetraglycerin, etc.), trimethylol alkanes (trimethylol ethane, trimethylol propane, trimethylol butane, etc.) and their 2- to 8-mer, pentaerythritol and their 2- to 4-mer, 1, 2, 4 -Butanetriol, 1,3,5-pentanetriol, 1,2,6-hexanetriol, 1,2,3,4-butanetetrol, sorbitol, sorbitan, sorbitol glycerin condensate, adonitol, arabitol, xylitol, mannitol Polyhydric alcohols such as xylose, arabinose, ribose, rhamnose, glucose, fructose, galactose, mannose, sorbose, cellobiose, maltose, isomaltose, trehalose, sucrose, etc., and mixtures thereof Etc., and the like.

  Examples of the ether include polyoxyalkylene glycol, dialkyl diphenyl ether, polyphenyl ether and the like.

  Examples of the hydrocarbon oil include poly α-olefin or a hydride thereof, isobutene oligomer or a hydride thereof, isoparaffin, alkylbenzene, alkylnaphthalene, and the like.

  These synthetic oils may be used individually by 1 type, and may be used combining 2 or more types by arbitrary ratios.

  Among the above, the lubricating base oil is preferably at least one selected from the group consisting of mineral oils and esters.

Kinematic viscosity at 40 ° C. of the lubricating base oil, the oil film component becomes sufficient, more excellent lubricity, in view of evaporation loss under high temperature conditions becomes smaller, preferably 20 mm 2 / ^s or more, more preferably 25 mm ² / S or more, more preferably 30 mm ² / s or more. The kinematic viscosity at 40 ° C. of the lubricating base oil is preferably 100 mm ² / s or less, more preferably 80 mm ² / s or less, and still more preferably 60 mm ² from the viewpoint of improving low-temperature viscosity characteristics and further improving fuel economy. / S or less.

Kinematic viscosity at 100 ° C. of the lubricating base oil, oil film formation becomes sufficient, more excellent lubricity, in view of evaporation loss under high temperature conditions becomes smaller, preferably 5 mm 2 / ^s or more, more preferably 6 mm ² / S or more, more preferably 7 mm ² / s or more. The kinematic viscosity at 100 ° C. of the lubricating base oil is preferably 20 mm ² / s or less, more preferably 15 mm ² / s or less, and still more preferably 10 mm ² from the viewpoint of improving low temperature viscosity characteristics and further improving fuel economy. / S or less.

  The kinematic viscosity in the present invention means a kinematic viscosity measured according to JIS K2283: 2000.

  The content of the lubricating base oil may be, for example, 50% by mass or more, 70% by mass or more, or 90% by mass or more based on the total amount of the lubricating oil composition.

  The hydraulic fluid composition according to the present embodiment includes a compound represented by the following general formula (1) in addition to the lubricating base oil.

In Formula (1), R ¹ represents a monovalent hydrocarbon group, preferably a linear or branched alkyl group, and more preferably a linear alkyl group. The carbon number of the monovalent hydrocarbon group or alkyl group represented by R ¹ is preferably 6 to 24, more preferably 8 to 18, and still more preferably 12 to 18. Examples of the monovalent hydrocarbon group or alkyl group represented by R ¹ include an octyl group, a stearyl group, a dodecyl group, a decyl group, and a hexyl group. Among them, the oily effect of the hydraulic fluid composition is exemplified. From the viewpoint of further improvement, R ¹ is preferably an octyl group, a stearyl group, or a dodecyl group.

In formula (1), R ² and R ³ each independently represent a hydrogen atom or an alkyl group. The alkyl group preferably has 1 to 8 carbon atoms, more preferably 1 to 3 carbon atoms. From the viewpoint of further improving the wear preventing effect of the hydraulic fluid composition, R ² and R ³ are each independently preferably a hydrogen atom, a methyl group, or an ethyl group.

  Examples of the compound represented by the general formula (1) include dimethyl stearyl phosphonate, ethyl stearyl phosphonate, diethyl stearyl phosphonate, diethyl octyl phosphonate, dimethyl dodecyl phosphonate, dimethyl decyl phosphonate, and the like.

  The compound represented by the general formula (1) can be obtained, for example, by reacting an olefin with a dialkylphosphonic acid.

  In the hydraulic fluid composition, the compound represented by the general formula (1) may be used singly or in combination of two or more. The content of the compound represented by the general formula (1) is preferably 0.05% by mass or more, more preferably 0.3% by mass or more, from the viewpoint of load resistance, based on the total amount of the hydraulic fluid composition. More preferably, it is 0.5% by mass or more. The content of the compound represented by the general formula (1) is preferably 1.0% by mass or less, more preferably 0.9% by mass or less, from the viewpoint of long life, based on the total amount of the hydraulic fluid composition. More preferably, it is 0.8 mass% or less. When the hydraulic fluid composition contains two or more compounds represented by the general formula (1), the above content is the total content of the two or more compounds.

  The hydraulic fluid composition according to this embodiment may further contain other additives as long as the effects of the present invention are not significantly impaired. Other additives include, for example, extreme pressure agents, antiwear agents, load bearing additives such as oiliness agents (friction modifiers) (excluding the compounds represented by the above general formula (1)), clean Dispersants, antioxidants, metal deactivators, viscosity index improvers, antifoaming agents, pour point depressants, corrosion inhibitors, rust inhibitors, demulsifiers, and the like.

  Examples of the load bearing additive include ashless friction modifiers and higher fatty acids. From the viewpoint of ensuring the long-term stability of the hydraulic fluid composition, the content of the load bearing additive is preferably 1.0% by mass or less based on the total amount of the hydraulic fluid composition, 0.5 The content is more preferably at most mass%, further preferably at most 0.3 mass%, particularly preferably not substantially contained.

  In addition, the content of the detergent dispersant is preferably 5.0% by mass or less based on the total amount of the hydraulic fluid composition, from the viewpoint of securing the demulsibility of the hydraulic fluid composition. The content is more preferably 0% by mass or less, further preferably 1.0% by mass or less, and particularly preferably substantially not contained.

The kinematic viscosity at 40 ° C. of the hydraulic fluid composition is preferably 20 mm ² / s or more, more preferably 25 mm, from the viewpoint of sufficient oil film formation, excellent lubricity, and smaller evaporation loss under high temperature conditions. ^{It is 2} / s or more, more preferably 30 mm ² / s or more. The kinematic viscosity at 40 ° C. of the hydraulic fluid composition is preferably 100 mm ² / s or less, more preferably 80 mm ² / s or less, and still more preferably 60 mm from the viewpoint of improving low-temperature viscosity characteristics and further improving fuel economy. ² / s or less.

The kinematic viscosity at 100 ° C. of the hydraulic fluid composition is preferably 5 mm ² / s or more, more preferably 6 mm from the viewpoint of sufficient oil film formation, excellent lubricity, and smaller evaporation loss under high temperature conditions. ^{It is 2} / s or more, more preferably 7 mm ² / s or more. The kinematic viscosity at 100 ° C. of the hydraulic fluid composition is preferably 20 mm ² / s or less, more preferably 15 mm ² / s or less, and still more preferably 10 mm, from the viewpoint of improving low-temperature viscosity characteristics and further improving fuel economy. ² / s or less.

  The phosphorus content in the hydraulic fluid composition is preferably 1000 ppm by mass or less, more preferably 800 ppm by mass or less, and even more preferably 600 ppm by mass or less, based on the total amount of the hydraulic fluid composition. The lower limit of the phosphorus content in the hydraulic fluid composition is not particularly limited, but is, for example, 100 ppm by mass or more, or 300 ppm by mass or more based on the total amount of the hydraulic fluid composition. The “phosphorus content” in the present invention means the content measured by ICP elemental analysis.

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to a following example.

(Lubricant base oil)
The following base oil A1 was used as the lubricating base oil.

A1: Mineral oil (Group III, kinematic viscosity at 40 ° C .: 35.7 mm ² / s)

(Additive)
As additives, the following additives B1 to B4 were used, respectively.

B1: Dimethylstearylphosphonate represented by the following formula (1-1) (DMSP, Mw: 362, phosphorus content: 8.56% by mass)

B2: Diethyl stearyl phosphonate represented by the following formula (1-2) (DESP, Mw: 390, phosphorus content: 7.94% by mass)

B3: Ethyl stearyl phosphonate represented by the following formula (1-3) (ESP, Mw: 362, phosphorus content: 8.56% by mass)

B4: tricresyl phosphate (TCP, phosphorus content: 8.4% by mass)

  A method for synthesizing the additives B1 to B3 will be described below.

(Synthesis of Additive B1)
1-dodecene (38 g, 0.226 mol) and dimethyl hydrogen phosphite (79.7 g, 0.69 mol) are collected in a vessel equipped with a stirrer, condenser and nitrogen sparger, and nitrogen is dispersed while stirring. Di-t-butyl peroxide (3 ml) was added. This mixture was stirred at room temperature for 10 minutes and then reacted at about 130 ° C. for 2 hours to obtain an additive B1 (dimethylstearyl phosphonate represented by the formula (1-1)).

(Synthesis of Additive B2)
In the same manner as additive B1, except that diethyl hydrogen phosphite (100 g, 0.69 mol) was used instead of dimethyl hydrogen phosphite (79.7 g, 0.69 mol), additive B2 (formula Diethyl stearyl phosphonate represented by (1-2) was obtained.

(Synthesis of Additive B3)
Additive B3 in the same manner as Additive B1, except that ethyl hydrogen phosphite (79.7 g, 0.69 mol) was used instead of dimethyl hydrogen phosphite (79.7 g, 0.69 mol). (Ethyl stearyl phosphonate represented by the formula (1-3)) was obtained.

  Using the base oil A1 and additives B1 to B4, a hydraulic fluid composition (composition based on the total amount of hydraulic fluid composition, mass%) having the composition shown in Table 1 was prepared.

(Evaluation of hydraulic fluid composition)
By the method shown below, the anti-wear effect in the middle load region and the oily effect in the low load region were evaluated.

<Evaluation of wear prevention effect>
Under the conditions shown below, a quaternary test (ASTM D 4172) was conducted, and the wear scar diameter (mm) was measured to evaluate the wear prevention effect. It can be said that the smaller the wear scar diameter, the better the anti-wear effect. The results are shown in Table 1.
Load: 294N
Rotation speed: 1200rpm
Temperature: 75 ° C
Test time: 1 hour

<Evaluation of oily effect>
Using a block-on-ring testing machine (LFW-1) described in ASTM D 2174, the friction coefficient (μ) of the hydraulic fluid composition was measured under the following conditions to evaluate the oily effect of the hydraulic fluid composition. . The results are shown in Table 1. In this test, the smaller the friction coefficient, the better the oily effect.
Test piece (ring): Falex S-10 Test Ring (SAE 4620 Steel)
Test piece (block): Falex H-60 Test Block (SAE01 Steel)
Oil temperature: 60 ° C
Load: 150N

  The test was carried out for 30 minutes at a peripheral speed (sliding speed) of 1 m / s, then the peripheral speed was reduced to 0.05 m / s, and the coefficient of friction for 5 minutes in the peripheral speed region was measured.

Claims (1)

A hydraulic fluid composition comprising a lubricating base oil and a compound represented by the following general formula (1).

[In Formula (1), R ¹ represents a monovalent hydrocarbon group, and R ² and R ³ each independently represent a hydrogen atom or an alkyl group. ]