JPH0565491A - Hydraulic working fluid - Google Patents

Abstract

(57) [Summary] [Structure] The hydraulic fluid of the present invention may be polyalkylene glycol alone or may have a viscosity of 170 to 30000 at 40 ° C.
A mixed oil of a high viscosity polyalkylene glycol having a cSt and a low viscosity oil having a viscosity of 5 to 170 cSt at 40 ° C., and a mixed oil of a polyalkylene glycol and a viscosity index improver having a higher viscosity than the polyalkylene glycol. The viscosity at 40 ° C. is 170 to 1000 cSt. [Effect] The hydraulic oil of the present invention can maintain high viscosity and have a high viscosity index, and can utilize the low temperature fluidity, wear resistance and oxidation stability of the synthetic lubricating oil itself. It can be regarded as a high-performance hydraulic fluid, and is suitable as a hydraulic fluid for door arc rotors, floor hinges, torque converters, and shock absorbers.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to hydraulic fluid, and more particularly to hydraulic fluid used for door rosers, floor hinges and the like.

[0002]

2. Description of the Related Art Hydraulic shock absorbers such as door rosers are widely used to smoothly open and close doors. For example, a door roser mainly consists of a cylinder, a piston, and hydraulic fluid.The operation of the cylinder and piston is made to pass the hydraulic fluid at a constant speed through an orifice provided in the cylinder section, and the door is opened and closed at a constant rate. It has the function of

In such a door roser,
Since the opening / closing performance of the door depends on the orifice passage speed of the hydraulic fluid, in order to keep the opening / closing performance of the door constant, the hydraulic fluid is required to have a small viscosity change due to temperature change, that is, a high viscosity index, Further, wear resistance to the gear portion of the door roser is also required.

At present, as a hydraulic fluid, a mineral oil to which a viscosity index improver is added is used. However, in order to achieve the above-mentioned problems in this type of hydraulic fluid, if a large amount of the viscosity index improver is added, the temperature will be low. Because it causes liquidity problems,
There are certain limits. Therefore, in the DOAR ROSER,
At present, a mechanism is provided for adjusting the diameter of the orifice to make the opening / closing property of the door constant.

However, with the recent miniaturization of door rosers, there is a demand for higher performance of hydraulic fluids, and even if the machining accuracy of the cylinders and pistons in the door rosers is low, the opening and closing properties of the door are improved. There is a demand for the provision of hydraulic fluid that can keep the oil pressure constant.

[0006]

Therefore, the present invention is
Suitable for various door rosers, floor hinges, etc.
An object is to provide a hydraulic fluid having a high viscosity index, low temperature fluidity, wear resistance, and oxidation stability.

[0007]

The first hydraulic fluid of the present invention is characterized by comprising polyalkylene glycol and having a viscosity at 40 ° C. of 170 to 1000 cSt.

The second hydraulic oil of the present invention is 40
Highly viscous polyalkylene glycol having a viscosity of 170 to 30,000 cSt at 5 ° C and a viscosity of 5 to 170 cS at 40 ° C.
It consists of a low viscosity oil that is t and has a viscosity of 170 at 40 ° C.
It is characterized by being ~ 1000 cSt.

Further, the third hydraulic fluid of the present invention comprises a polyalkylene glycol and a viscosity index improver having a viscosity higher than that of the polyalkylene glycol, and has a viscosity at 40 ° C. of 170 to 1000 cSt. Characterize.

Further, the hydraulic fluid of the present invention is characterized by adding at least one or more of an antiwear agent, an antioxidant and a corrosion inhibitor to the above hydraulic fluid.

The hydraulic oil of the present invention will be described in detail below.

First, the first hydraulic fluid of the present invention may be composed of polyalkylene glycol alone.

As such a polyalkylene glycol, the alkylene group has 2 to 5 carbon atoms, preferably 2 to 3 carbon atoms.
Is a ring-opening polymer or ring-opening copolymer of the linear or branched alkylene oxide. The alkylene oxide is ethylene oxide, propylene oxide, butylene oxide, or a mixture thereof, preferably propylene oxide. Preferably molecular weight 1000
The polyethylene glycol and the polypropylene glycol of -5000 can be mentioned. Both ends of the molecular chain are alkyl groups, one end is an alkyl group and the other end is a hydroxyl group, and both ends are hydroxyl groups. The terminal alkyl group has 1 to 18 carbon atoms.

The hydraulic fluid has a kinematic viscosity of 170 to 1000 at 40 ° C. obtained by adjusting the degree of polymerization.
cSt is used, and the viscosity index of such polyalkylene glycol is 190 to 300,
It has a high viscosity index suitable for hydraulic fluid. Further, it has been found that, because of its high viscosity, it is not significantly affected by downsizing of the doker and the processing accuracy, and has high wear resistance.

Further, these polyalkylene glycols also have a pour point of -20 ° C. or lower and are excellent in low temperature fluidity,
Furthermore, since it is excellent in oxidation stability, it satisfies various performances required for hydraulic fluid.

Next, the second hydraulic fluid of the present invention is the above-mentioned highly viscous polyalkylene glycol, further polyalkylene glycol having a higher molecular weight, having a viscosity of 170 to 30,000 cSt at 40 ° C. and a low viscosity. The viscosity index is further improved as compared with the case of using the above polyalkylene glycol alone, while mixing with oil and maintaining the viscosity at 40 ° C. at 170 to 1000 cSt.

Examples of such low-viscosity oils include low-viscosity olefin oligomers, alkylbenzenes and their derivatives,
Mineral oil, organic acid ester, phosphoric acid ester, low viscosity polyalkylene glycol, fluorinated oil and the like can be used. The kinematic viscosity of these low viscosity oils is 5 to 1 at 40 ° C.
A low viscosity oil of 70 cSt, preferably 10-100 cSt, may be used.

As the low-viscosity olefin oligomer, any one kind of homopolymer or two or more kinds selected from olefin hydrocarbons having or not having a branch having 2 to 14 carbon atoms, preferably having 4 to 12 carbon atoms. Which is obtained by the copolymerization of 1) and is selected from the products having an average molecular weight of 100 to about 2000, preferably 200 to about 1000, and the one in which the unsaturated bond is removed by hydrogenation is particularly preferable. Preferred olefin oligomers include, for example, polybutene, α-olefin oligomer, ethylene
Examples include α-olefin oligomers. As the polybutene, for example, one obtained mainly by isobutene and obtained by copolymerizing a monomer mixture of butene-1 and butene-2 is preferable.

As the α-olefin oligomer,
An α-olefin mixture having 6 to 12 carbon atoms obtained by thermal decomposition of hydrocarbon or trimerization to hexamerization of lower olefin, for example, hexene-1 is 25% to 50% by weight, octene-1 is 30% to 40% by weight. A copolymerized mixture of 25% by weight and 25% by weight to 40% by weight of decene-1 can be used.

Also suitable are oligomers obtained from a single monomer such as decene. Further, as the ethylene / α-olefin oligomer, ethylene is 40% by weight to 9%.
It is possible to use one obtained by mixing and polymerizing 0% by weight of an α-olefin, for example, 10% by weight to 60% by weight of a propylene monomer.

These olefin oligomers can be produced by using Friedel-Crafts type catalysts such as aluminum chloride and boron fluoride, Ziegler catalysts and oxide catalysts such as chromium oxide. In addition, hydrogenation of olefin oligomer is carried out by heating after removing the catalyst from the reaction product.
It can be carried out by contacting with a hydrogenation catalyst such as nickel-molybdenum / alumina under pressure.

Next, the alkylbenzene is mainly of the alkylbenzene type, which is a by-product when an aromatic hydrocarbon such as benzene or toluene is alkylated by the Friedel-Crafts reaction or the like to produce a detergent raw material. It is an oil containing a dialkylated aromatic hydrocarbon. As the alkyl group, either linear or branched ones belong to this group.

The mineral oil is a hydrocarbon oil fraction having a lubricating viscosity, for example, a raffinate obtained by subjecting a distillate under reduced pressure to an extraction treatment with a solvent such as phenol, furfural, or N-methylpyrrolidone to produce propane or methyl ethyl ketone. Hydrocarbon distillate obtained after solvent dewaxing with a solvent such as the above, and then subjecting it to further hydrorefining to improve the hue and remove unstable substances, or this hydrocarbon distillate Mixtures of oils with solvent extracted, solvent dewaxed and solvent dewaxed residual oils can be used. Further, catalytic dewaxing treatment may be performed instead of solvent dewaxing treatment. These refined mineral oils may be paraffinic oils, naphthenic oils or the like alone or mixed hydrocarbon oils in terms of composition.

Next, one of the organic acid esters is one obtained by reacting an aliphatic dibasic acid having 4 to 14 carbon atoms with an aliphatic alcohol having 4 to 14 carbon atoms.

The dibasic acid that can be used in the synthesis includes, for example, succinic acid, glutaric acid, adipic acid,
Piperic acid, suberic acid, azelaic acid, sebacic acid,
Undecanedioic acid, dodecanedioic acid, brassic acid, and tetradecanedioic acid, preferably adipic acid, azelaic acid,
Sebacic acid, dodecanedioic acid and the like can be mentioned,
Of these, adipic acid and sebacic acid are particularly preferable.

Examples of the aliphatic alcohol include n-butanol, isobutanol, n-amyl alcohol, isoamyl alcohol, n-hexanol, 2-ethylbutanol, cyclohexanol, n-heptanol, isoheptanol, methylcyclohexanol, n. -Octanol, dimethylhexanol, 2-ethylhexanol, 2,4,4-trimethylpentanol, isooctanol, 3,5,5-trimethylhexanol, isononanol, isodecanol, isoundecanol, 2
-Butyloctanol, tridecanol, isotetradecanol and the like can be mentioned, but 2-ethylhexanol, isodecanol and tridecanol are particularly preferable.

The diester can be synthesized from a dibasic acid and an alcohol by a conventional method, for example, dehydration condensation under an acidic catalyst. The diester thus obtained is, for example, di- (1-ethylpropyl) adipate, di- (3-methylbutyl) adipate, di-
(1,3-dimethylbutyl) adipate, di- (2-ethylbutyl) adipate, di (2-ethylhexyl)
Adipate, di- (isooctyl) adipate, di-
(Isononyl) adipate, di- (3,5,5 trimethylhexyl) adipate, di- (isodecyl) adipate, di- (undecyl) adipate, di- (tridecyl) adipate, di- (isotetradecyl) adipate, di- (2,2,4-trimethylpentyl) adipate, di- [mixed (2-ethylhexyl, isononyl)]
Adipate, di- (1-ethylpropyl) azelate,
Di- (2-ethylbutyl) azelate, di- (2-ethylhexyl) azelate, di (isooctyl) azelate, di- (isononyl) azelate, di- (3,5,5)
5 trimethylhexyl) azelate, di- (isodecyl) azelate, di- (tridecyl) azelate, di-
[Mixed (2-ethylhexyl, isononyl)] azelate, di- [mixed (2-ethylhexyl, decyl)] azelate, di- [mixed (2-ethylhexyl, isodecyl)] azelate, di- [mixed (2-ethylhexyl,
2-propylheptyl)] azelate, di- [mixture (2
-Ethylhexyl, decyl)] azelate, di- (n-
Butyl) sebacate, di- (isobutyl) sebacate,
Di- (1-ethylpropyl) sebacate, di- (3-methylbutyl) sebacate, di- (1,3-dimethylbutyl) sebacate, di- (2-ethylbutyl) sebacate, di- (2-ethylhexyl) sebacate, di -[2
-(2'-Ethylbutoxy) ethyl] sebacate, di-
(2,2,4-trimethylpentyl) sebacate, di-
(Isononyl) sebacate, di- (3,5,5 trimethylhexyl) sebacate, di- (isodecyl) sebacate, di- (isoundecyl) sebacate, di- (tridecyl) sebacate, di- (isotetradecyl) sebacate, di- [Mixed (2-ethylhexyl, isononyl)]
Sebacate, di- (2-ethylhexyl) glutarate, di- (isoundecyl) glutarate, di- (isotetradecyl) glutarate and the like can be mentioned.

Another type of organic acid ester is neopentyl polyol ester. The neopentyl polyol ester is produced by synthesizing a neopentyl polyol having 5 to 9 carbon atoms and an organic acid having 4 to 18 carbon atoms.

In the present invention, the neopentyl polyol is a polyhydric alcohol having a neopentyl group, such as 2,2-dimethylpropane-1,3-diol (ie neopentyl glycol), 2-ethyl-2-butyl. -Propane-1,3-diol, 2,2-diethylpropane-1,3-diol, 2,2-dibutylpropane-1,3-diol, 2-methyl-2-propylpropane-1,3-diol, 2-ethyl-2-butylpropane-1,3-diol, trimethylolethane, trimethylolpropane, trimethylolbutane, pentaerythritol, preferably neopentyl glycol, 2-
Methyl-2-propylpropane-1,3-diol, trimethylolpropane, pentaerythritol,
Particularly preferred are neopentyl glycol, trimethylolpropane and pentaerythritol.

The organic acids include, for example, n-butanoic acid, isobutanoic acid, n-pentanoic acid, isopentanoic acid, n-hexanoic acid, 2-ethylbutanoic acid, cyclohexanoic acid, n-heptanoic acid, isoheptanoic acid, methylcyclohexanoic acid,
n-octanoic acid, dimethylhexanoic acid, 2-ethylhexanoic acid, 2,4,4-trimethylpentanoic acid, isooctanoic acid, 3,5,5-trimethylhexanoic acid, n-nonanoic acid, isononanoic acid, isodecanoic acid, iso Undecanoic acid, 2-butyloctanoic acid, tridecanoic acid, tetradecanoic acid, hexadecanoic acid and octadecanoic acid are preferred, and heptanoic acid, n-octanoic acid and 2-ethylhexanoic acid are preferred.

The neopentyl polyol ester can be synthesized from the organic acid and neopentyl polyol by a conventional method, for example, a dehydration condensation method under an acidic catalyst.

Examples of the neopentyl polyol ester synthesized in this manner (hereinafter, neopentyl is referred to as NP
G, trimethylolpropane are abbreviated as TMP, and pentaerythritol is abbreviated as PE. ), For example, NPG.di- (heptanoate), NPG.di- (2-ethylbutyrate), NPG.di- (cyclohexanoate), NPG
-Di- (heptanoate), NPG-di- (isoheptanoate), NPG-di- (octylate), NPG-
Di- (2-ethylhexanoate), NPG.di- (isooctanoate), NPG.di- (isononylate), NPG.di- (isodecanoate), NPG.di- {mixed (hexanoate, heptanoate)} , NP
G-di- {mixed (hexanoate, octanoate)}, NPG-di- {mixed (hexanoate, nonylate)}, NPG-di- {mixed (heptanoate, octanoate)}, NPG-di- {mixed (heptanoate, nonylate) }, NPG / di- {mixed (heptanoate, isooctanoate)}, NPG / di- {mixed (heptanoate, isononilate)}, NPG / di-
{Mixed (isooctanoate, isononilate)}, N
PG-di- {mixed (butanoate, tridecanoate)}, NPG-di- {mixed (butanoate, tetradecanoate)}, NPG-di- {mixed (butanoate,
Hexadecanoate)}, NPG • di- {mixed (butanoate, octadecanoate)}, NPG • di- {mixed (hexanoate, isooctanoate, isononilate)}, NPG • di- {mixed (hexanoate, Isooctanoate, isodecanoate)}, NPG / di-
{Mixed (heptanoate, isooctanoate, isononylate)}, NPG / di- {mixed (heptanoate,
Isooctanoate, isodecanoate)}, NPG
Di- {mixed (octanoate, isononilate, isodecanoate)}, TMP-tri- (pentanoate),
TMP ・ Tri- (hexanoate), TMP ・ Tri-
(Heptanoate), TMP.tri- (octanoate), TMP.tri- (nonylate), TMP.tri-
(Isopentanoate), TMP.tri- (2-ethylbutyrate), TMP.tri- (isopentanoate), TMP.tri- (isooctanoate), TMP
-Tri- (2-ethylhexanoate), TMP-tri- (isononylate), TMP-tri- (isodecanoate), TMP-tri- [mixture (butyrate, octadecanoate)], TMP-tri- [mixture (Hexanoate, Hexadecanoate)], TMP · Tri- [Mixed (Heptanoate, Tridecanoate)], TMP · Tri- [Mixed (Octanoate, Decanoate)], TM
P. tri- [mixture (octanoate, nonylate)],
TMP tri- [mixed (butyrate, heptanoate,
Octadecanoate)], TMP-tri- [mixture (pentanoate, heptanoate, tridecanoate)],
TMP tri- [mixture (hexanoate, heptanoate, octanoate)], PE tetra (pentanoate), PE tetra (hexanoate), PE tetra (isopentanoate), PE tetra (2-ethyl butyrate) ), PE • tetra (isoheptanoate), PE • tetra (isooctanoate), PE • tetra (2-ethylhexanoate), PE • tetra (isononylate) and PE and a direct carbon number of 4 to 8 Esters with a mixture of chain or branched carboxylic acids. Also, N
Neopentyl polyol other than PG, TMP and PE,
That is, 2-methyl-2-propylpropane-1,3-diol, 2,2-diethylpropanediol, trimethylolethane and trimethylolhexane and the above-mentioned organic acid alone or a mixture with a polyol ester may be mentioned.

As the phosphoric acid ester, tricresyl phosphate, tritolyl phosphate, tri (2-ethylhexyl) phosphate, alkylphenyl phosphate, alkylphenylphenyl phosphate and the like can be used.

As the low-viscosity polyalkylene glycol, the high-viscosity polyalkylene glycol is the same as the above-mentioned high-viscosity polyalkylene glycol, but the low-viscosity polyalkylene glycol has a low viscosity by adjusting the degree of polymerization, and has a molecular weight range of 100 to 2,000. And preferably from 200 to 1000.

Further, as the fluorinated oil, polychlorotrifluoroethylene represented by the following formula:-(CF ₂ -CFCl) _n- (wherein, n is 4 to 18) having a molecular weight of 500 to 2000, _{F - [CF (CF 3)} -CF 2 -O] n -CF 2 CF 3 ( wherein, n ~) can be used as such a molecular weight from 1,500 to 7,000 represented by.

A second hydraulic fluid of the present invention is a hydraulic fluid having a viscosity at 40 ° C. of 170 to 1000 cSt by mixing the high viscosity polyalkylene glycol with the low viscosity oil. As a result, the hydraulic fluid can have a viscosity index in the range of 200 to 400 while maintaining high viscosity.

Next, the third hydraulic fluid of the present invention will be described.

The third hydraulic fluid of the present invention maintains a high viscosity by adding a viscosity index improver to polyalkylene glycol to obtain a hydraulic fluid having a viscosity range of 170 to 1000 cSt at 40 ° C. On the other hand, the viscosity index can be further improved.

By using a viscosity index improver having a viscosity higher than that of polyalkylene glycol, the viscosity index of the hydraulic fluid can be improved.

As such a viscosity index improver, α-
Olefin oligomer, polymethacrylate, polyisobutylene, polyalkylstyrene, ethylene-propylene copolymer, styrene-diene hydrogenated copolymer, styrene-maleic anhydride copolymer, etc. can be used.

As the α-olefin oligomer, any one kind of homopolymer or di-olefin selected from olefinic hydrocarbons having or not having a branch having 35 to 3,500, preferably 50 to 700 carbon atoms is used. It is obtained by the copolymerization of one or more species and has an average molecular weight of 500 to 5
It is selected from 50,000, preferably 700 to 10,000 products, particularly those having unsaturated bonds removed by hydrogenation are preferable. Preferred olefin oligomers are, for example, polybutene, α-olefin oligomer, ethylene / α-olefin oligomer and the like. Four
A kinematic viscosity at 0 ° C. of 10 to 10,000 cSt can be used.

As the polymethacrylate, an alkyl group having 1 to 18 carbon atoms is used as an ester component, and a homopolymer having a degree of polymerization of 5 or more such as polymethacrylate or polyacrylate, or methacrylic acid or acrylic acid is used as a copolymer component. Is a copolymer. As the non-dispersion type polymethacrylate, the alcohol component forming the ester is an alkyl group having 1 to 16 carbon atoms and an average molecular weight of 20,000 to 1
As for 500,000, dispersed polymethacrylate, the alcohol component forming the ester has 1 to 16 carbon atoms.
A copolymer of methacrylic acid, which is an alkyl group, and ethylene or propylene substituted with a polar group and having an average molecular weight of 20,000 to 1,500,000 can be used.

Although the hydraulic fluid of the present invention has been described above, the hydraulic fluid of the present invention has a high viscosity, is excellent in abrasion resistance by itself, and is itself excellent in oxidation resistance as a synthetic lubricating oil. However, it is desirable to add at least one or more of an antiwear agent, an antioxidant and a corrosion inhibitor.

As such an antiwear agent, as a phosphorus antiwear agent, a compound containing at least one of the following structures (1) to (29) in general formula is effective. In the following formula, R is hydrogen, an alkyl group, an aryl group, or a benzyl group, and may be the same or different.

[0045]

[Chemical 1]

[0046]

[Chemical 2]

Specific compounds are shown below.

Examples of the compound represented by the above structural formula (1) include triaryl phosphate and the like. Examples thereof include benzyl diphenyl phosphate, allyl diphenyl phosphate, triphenyl phosphate, tricresyl phosphate, ethyl diphenyl phosphate. ,
Tributyl phosphate, dibutyl phosphate,
Cresyl diphenyl phosphate, dicresyl phenyl phosphate, ethyl phenyl diphenyl phosphate, diethyl phenyl phenyl phosphate, propyl phenyl diphenyl phosphate, dipropyl phenyl phenyl phosphate, triethyl phenyl phosphate, tripropyl phenyl phosphate, butyl phenyl Phosphoric acid esters such as diphenyl phosphate, dibutyl phenyl phenyl phosphate, tributyl phenyl phosphate, propyl phenyl phenyl phosphate mixture, butyl phenyl phenyl phosphate mixture, lauryl acid phosphate, stearyl acid phosphate, di-
There are acidic phosphoric acid esters such as 2-ethylhexyl phosphate.

Examples of the compound represented by the structural formula (2) include di-n-butylhexylphosphonate.

The compound represented by the structural formula (3) includes n
-Butyl-n-dioctyl phosphinate and the like.

Examples of the compound represented by the structural formula (5) include triarylphosphorothionate and the like, and examples thereof include triphenylphosphorothionate and alkyl diary.
Such as ruphosphorothionate.

Examples of the compound represented by the structural formula (15) include triisopropyl phosphite and diisopropyl phosphite.

Examples of the compound represented by the structural formula (16) include trilauryl thiophosphite.

Examples of the compound represented by the structural formula (22) include hexamethylphosphoric triamide.

Examples of the compound represented by the structural formula (24) include dibutylphosphoroamidate.

Examples of the compound represented by the structural formula (28) include R
There is an octyl group.

Examples of the compound represented by the structural formula (29) include R
There is an octyl group.

As the sulfur-based antiwear agent, sulfides such as diphenyl sulfide, diphenyl disulfide, di-n-butyl sulfide, di-n-butyl disulfide, di-tert-dodecyl disulfide and di-tert-dodecyl trisulfide, Sulfurized palm oil,
Sulfurized dipentene and other sulfurized oils and fats, xanthic disulfide and other thiocarbonates, primary alkyl zinc thiophosphates, secondary alkyl zinc thiophosphates, alkyl-allyl thiophosphoric acid zinc, allyl thiophosphoric acid zinc anti-wear agents Can be used.

The proportion of the antiwear agent used is 0.01% to 5% by weight, preferably 0.1% to 3% by weight, based on the hydraulic fluid. The antiwear agents may be used alone or in combination of two or more.

Examples of the antioxidant include dioctyldiphenylamine, phenyl-α-naphthylamine, alkyldiphenylamine, N-nitrosodiphenylamine, phenothiazine, N, N'-dinaphthyl-p.
1. amine-based antioxidants such as phenylenediamine, acridine, N-methylphenothiazine, N-ethylphenothiazine, dipyridylamine, diphenylamine, phenolamine, 2,6-di-t-butyl-α-dimethylaminoparacresol, 2. A phenolic antioxidant such as 6-di-t-butylparacresol, 4.4'-methylenebis (2.6-di-t-butylphenol), 2.6-di-t-butylphenol and the like. In addition, organic iron salts such as iron octoate, ferrocene, iron naphthoate, organic cerium salts such as cerium naphthoate and cerium toluate, organometallic compounds such as organic zirconium salts such as zirconium octoate. It is recommended to use a system antioxidant. Further, the above antioxidants may be used alone, or may be used in combination of two or more so as to exert a synergistic effect.

The antioxidant may be used in an amount of 0.001 to 5% by weight, preferably 0.01 to 2% by weight, based on the hydraulic fluid.

As the corrosion inhibitors, benzotriazole and its derivatives, imidazoline and pyrimidine derivatives are used as nitrogen compounds, and 1,3,4-thiadiazole polysulfide, 1,3,3 are used as compounds containing sulfur and nitrogen.
4-thiadiazolyl-2,5-bisdialkyldithiocarbamate, 2- (alkyldithio) benzimidazole, etc., and β- (o-carboxybenzylthio) propionnitrile, propionic acid, etc. can be used. On the other hand, 0.001 to 5% by weight, preferably 0.01 to 1.0% by weight is used.

[0063]

The hydraulic fluid of the present invention is a polyalkylene glycol alone or has a viscosity of 170 at 40 ° C.
A mixture of a highly viscous polyalkylene glycol having a viscosity of up to 30,000 cSt and a low viscosity oil having a viscosity of 5 to 170 cSt at 40 ° C., and a mixture of a polyalkylene glycol and a viscosity index improver having a viscosity higher than that of the polyalkylene glycol. Oil with a viscosity of 170-1000 cSt at 40 ° C
As a result, the viscosity index can be made high and the high viscosity can be maintained, so it is possible to reduce the size and processing accuracy of the DOAR ROSER, and the synthetic lubricating oil itself has Since it has low-temperature fluidity, wear resistance, and oxidation stability, it is a high-performance hydraulic fluid.

As a result, the hydraulic fluid of the present invention is used as a door closer, a floor hinge, a general industrial machine and a construction machine, and is particularly suitable as a hydraulic fluid for a door closer, a floor hinge, a torque converter and a shock absorber. It is a thing.

The present invention will be described in detail below with reference to examples.

[0066]

Example 1 The following sample oil was prepared as a hydraulic fluid.

Sample oil 1 ... Polyoxypropylene glycol monobutyl ether (kinematic viscosity at 40 ° C. 330 cSt
) Sample oil 2 ... Polyoxyethylene oxypropylene glycol monobutyl ether {EO: PO 50:50
(Wt%)} (Kinematic viscosity at 40 ° C 412 cSt) Sample oil 3 ··· Kinematic viscosity at 40 ° C 945 cSt, viscosity index 2
A mixed oil of 80 parts by weight of 86 polyoxyethyleneoxypropylene glycol monobutyl ether {EO: PO 50:50 (wt%)} and 20 parts by weight of triethylene glycol monomethyl ether having a kinematic viscosity of 4 cSt at 40 ° C. (40 ° C. Kinematic viscosity at 380 cSt) Sample oil 4.Kinematic viscosity at 40 ° C 945 cSt, viscosity index 2
80 parts by weight of 86 polyoxyethylene oxypropylene glycol monobutyl ether {EO: PO 50:50 (wt%)} and a kinematic viscosity at 40 ° C. of 11.8 cSt,
Mixed oil with 20 parts by weight of diisooctyl azelate having a viscosity index of 169 (kinematic viscosity 415 cSt at 40 ° C) Sample oil 5 ··· Viscosity to polyoxypropylene glycol having a viscosity index of 24.3 cSt and viscosity index 136 of 136 Dispersion type polymethacrylate (molecular weight 4100
0) 40% by weight mixed oil (kinematic viscosity at 40 ° C. 424 cSt) Sample oil 6 ... Sample oil 1 with 0.5% by weight of dilauryl hydrogen phosphite as an anti-wear agent and as an antioxidant Mixed oil containing 0.2% by weight of 4,4-methylenebis (2,6-di-t-butylphenol) Sample oil 7 ... Mixing sample oil 2 with the same amount of additive as sample oil 6 Oil Sample oil 8 ... Mixed oil containing the same amount of additive as sample oil 6 in sample oil 3 Sample oil 9 ... Mixed oil containing the same amount of additive as sample oil 6 in sample oil 4 Sample Oil 10 ... Mixed oil containing the same amount of additive as sample oil 5 in sample oil 5 Comparative oil 1 ... Sample against 95 parts by weight of mineral oil (kinematic viscosity at 40 ° C., 20 cSt, viscosity index 108) A mixed oil containing 5% by weight of the viscosity index improver used in Oil 5 (at 40 ° C. Viscosity 32 cSt, viscosity index 190) Comparative oil 2 ... 20% by weight of the viscosity index improver used in sample oil 5 was added to 80 parts by weight of mineral oil (kinematic viscosity at 40 ° C., 20 cSt, viscosity index 108). Mixed oil (kinematic viscosity at 40 ° C, 110 cSt, viscosity index 250) The viscosity index of each of these sample oil comparative oils was measured in accordance with JIS K 2283 and the pour point in accordance with JIS K 2269, and the load resistance was measured by Falex. Using a testing machine, the seizure load (unit: pound) was measured by the extreme pressure evaluation method.

The test results are shown below.

[0069]

[Table 1]

As can be seen from the table, the hydraulic oil of the present invention is
It can be seen that it has excellent temperature-viscosity characteristics, low-temperature fluidity, and load resistance, and is suitable as a hydraulic fluid.

[0071]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location C10M 137: 04 129: 14) C10N 20:02 30:02 30:06 30:10 30:12 40 : 08 (72) Inventor Tetsuo Miyamoto 1-3-1 Nishitsurugaoka, Oi-cho, Iruma-gun, Saitama Tonen Co., Ltd.

Claims (4)

[Claims] 1. A polyalkylene glycol comprising 4
A hydraulic fluid having a viscosity of 170 to 1000 cSt at 0 ° C. 2. The viscosity at 40 ° C. is 170 to 30000 cS.
a high viscosity polyalkylene glycol of t and a low viscosity oil having a viscosity of 5 to 170 cSt at 40 ° C.
A hydraulic fluid having a viscosity of 170 to 1000 cSt at ° C. 3. A hydraulic fluid comprising a polyalkylene glycol and a viscosity index improver having a viscosity higher than that of the polyalkylene glycol, and having a viscosity at 40 ° C. of 170 to 1000 cSt. 4. The hydraulic fluid according to claim 1, further comprising at least one of an antiwear agent, an antioxidant and a corrosion inhibitor added to the hydraulic fluid. ..