JPH0737627B2 - Hydraulic oil composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention uses low molecular weight polyethylene glycol as a base oil, to which a high molecular weight polyoxyethylene / oxypropylene copolymer is added as a thickener. The present invention relates to a hydraulic oil composition that does not give an unpleasant odor when used for a long time as well as when used as a new oil.

[Conventional technology]

In recent years, the industry is making more and more efforts to improve the work environment.However, when using conventional mineral oil-based hydraulic oil for hydraulic systems, the odor generated from the hydraulic oil may deteriorate the work environment. However, it has become an important problem for occupational health.

In addition, the hydraulic drive of elevators has become
Introducing a hydraulic system into the home (for example, opening and closing doors,
With the deepening of the involvement of the hydraulic system in daily life such as automatic raising and lowering of the underfloor storage, movement of beds for the elderly and the sick, etc. Giving pleasure is a major bottleneck in the spread of hydraulic systems.

The deterioration of the work environment / living environment due to the leakage of hydraulic oil is one of the important measures to be taken to prevent leakage of hydraulic oil from the hydraulic system. Despite the improvements and improvements made to, no leak-free device has been developed to date.

[Problems to be solved by the invention]

Therefore, if the unpleasant odor can be solved by the hydraulic oil itself, it can be said that it is the best method as a whole and is extremely economically advantageous. Therefore, it is extremely useful to develop a hydraulic oil that does not give an unpleasant odor not only when it is a new oil but also when it is used for a long time.

The present inventors have conducted extensive studies in view of the above points, and by using a polyalkylene glycol as a base oil, paying attention to the fact that the hydraulic oil is less deteriorated, and that the unpleasant odor upon deterioration is small. It was found that polyethylene glycol does not give an unpleasant odor.

The present invention has been made based on the above findings, and in order to solve the drawback that the pour point of the hydraulic oil becomes too high to be put to practical use when trying to obtain an appropriate viscosity as the hydraulic oil only with polyethylene glycol. By using low molecular weight polyethylene glycol with a low pour point as a base oil and adding a thickener to this until it reaches an appropriate viscosity, there is no unpleasant odor when using new oil, and when using it for a long period of time. Another object of the present invention is to provide a hydraulic oil composition in which the hydraulic oil is not easily deteriorated and does not give an unpleasant odor even when deteriorated.

Furthermore, by predicting that the housing environment will become more cultural and comfortable in the future, and by making the public and welfare facilities fields non-polluting, non-marked, and fragrant, housing and silver It is intended to provide an elegant hydraulic oil composition suitable for the industrial field.

[Means and Actions for Solving Problems]

The hydraulic oil composition of the present invention comprises 90 to 99.9 wt% of a base oil consisting of polyethylene glycol having a number average molecular weight of 100 to 300 and 10 to 0.1 wt% of a polyoxyethylene / oxypropylene copolymer having a number average molecular weight of 3,000 to 200,000. It is characterized by having as a main component.

That is, a hydraulic oil composition is characterized in that a low molecular weight polyethylene glycol is used as a base oil, and a specific high molecular weight polyoxyethylene / oxypropylene copolymer is added as a thickener to the base oil. The base oil, polyethylene glycol, has a number average molecular weight (hereinafter, abbreviated as molecular weight Mw) of about 100 to 300. The thickener is a random copolymer or block copolymer of ethylene oxide and propylene oxide, or a derivative thereof, and has a molecular weight Mw of about 3,
000-200,000, ethylene oxide unit content is 50wt%
About 0.1-10 wt% of the above is added.

In the present invention, polyethylene glycol is used as the base oil. Viscosity number VG32 (viscosity at 40 ℃, 28.8-35.2cSt) determined by International Organization for Standardization (ISO) as a hydraulic oil, V
If polyethylene glycol is used as the base oil for G46 (41.1 to 50.6 cSt) and VG68 (61.2 to 74.8 cSt) products, the molecular weight Mw of polyethylene glycol is 300.
Must be in the range of ~ 1,000. However, in this molecular weight range, the pour point of the product is -10 to + 30 ° C, which does not satisfy the required pour point requirement of -15 ° C or lower for hydraulic oil. Therefore, generally, as a base oil, it has been conventionally performed to lower the pour point by using a copolymer of ethylene oxide and propylene oxide, but such a composition cannot solve the problem of unpleasant odor.

In the present invention, such a low molecular weight that does not reach the proper viscosity of the hydraulic oil by itself, i.e., a polyethylene glycol having a molecular weight Mw of about 300 or less is used as a base oil, and the lack of viscosity is set to satisfy the proper viscosity VG32 to VG68. About 0.1-10w thickener
t% is added. If the viscosity of the thickener is less than about 0.1 wt%, the viscosity does not fall within the required range, and if the viscosity of the thickener exceeds about 10 wt%, the viscosity becomes larger than the required property, which is not preferable.

The base oil used in the present invention is polyethylene glycol represented by the formula (I) and has a molecular weight Mw of about 100 to 300, preferably about 100.
The range of 130 to 280, especially about 200, is preferable. In the formula (I), n is a positive integer. The content of this polyethylene glycol in the hydraulic fluid composition of the present invention is 90 to 99.9 wt%.

_{HO- (CH 2 -CH 2 -O)} n-H ...... (I) · Polyoxyethylene high molecular weight as thickener (b)
An oxypropylene copolymer is used. Such copolymers are known as thickeners for hydraulic fluids such as water-glycol type nonflammable hydraulic fluids and brake fluids, and these copolymers include, for example, water, monohydric alcohols and polyhydric alcohols. It is prepared by copolymerizing ethylene oxide and propylene oxide with a compound having active hydrogen such as alcohol, polyalkylene polyamine and polyamide. Examples of this polyoxyethylene / oxypropylene copolymer include (II)
Polyoxyalkylene glycol by copolymerization of ethylene oxide and propylene oxide as shown in the general formula, its alkyl ether, and derivatives of polyoxyalkylene glycol, such as polyhydric alcohol,
Examples thereof include polyoxyalkylene polyols obtained by copolymerizing ethylene oxide and propylene oxide using polyalkylene polyamine, polyamide, etc. as starting materials.

R ₁ O- (C ₂ H ₄ O) m- (C ₃ H ₆ O) n-H (II) (wherein m and n are positive integers, R ₁ is hydrogen or 1 to carbon atoms)
Represents 20 alkyl groups. ) These copolymers may be used as a mixture of one or more kinds. Specific examples of these polyoxyethylene / oxypropylene copolymers include polyoxyalkylene glycols; monohydric alcohol polyoxyalkylene glycols; polyhydric alcohol polyoxyalkylene polyols such as Newpol 75H90000 (Sanyo Chemical Co., Ltd.) and Unilube 75DE.
Polyoxyalkylene glycols such as 3800 (Nippon Oil and Fats), polyoxyalkylene triols such as Newpol V-10-C (Sanyo Kasei), Carpol GH-10 (Adeka), JP-A-54-105653 Polyoxyalkylene polyols described; alkylene polyamines and polyoxyalkylene polyols of polyalkylene polyamines,
Examples thereof include polyoxyalkylene polyols described in JP-A-54-129256; polyoxyalkylene polyols of polyamides, such as polyoxyalkylene polyols described in JP-B-51-44275 (JP-A-57-105492). Issue). Examples of starting materials for these copolymers are monohydric alcohols such as butyl alcohol, octyl alcohol, lauryl alcohol, oleyl alcohol; polyhydric alcohols such as ethylene glycol, propylene glycol, glycerin, diethylene glycol, dipropylene glycol, trimethylolpropane. , Polyhydric alcohols such as pentaerythritol, dipentaerythritol and polyglycerin, sugars such as glucose, galactose, saccharose and sorbit; alkylene polyamines and polyalkylene polyamines such as ethylenediamine, diethylenetriamine, tetraethylenepentamine, pentaethylenehexamine and dipropylene. Triamines, poly (hexamethylene) polyamines, etc .; Polyamides, such as dimer acid and phenol Acid amides of data hexamine include acid amides of succinic acid and diethylenetriamine. These polyoxyethylene / oxypropylene copolymers generally use an alkali catalyst such as sodium hydroxide or potassium hydroxide at a temperature of about 60 to 180 ° C. and ethylene oxide and propylene oxide as starting materials having active hydrogen. Is produced by addition polymerization. The terminal hydroxyl group may be etherified. The polyoxyethylene / oxypropylene copolymer in the present invention may be a random copolymer of ethylene oxide and propylene oxide or a block copolymer.

The polyoxyethylene / oxypropylene copolymer used as the thickener in the present invention may be any of the above-mentioned types, but those having a number average molecular weight of about 3,000 to 200,000, preferably about 5,000 to 100,000 are used. . A suitable content of ethylene oxide units in the thickener is not less than about 50 wt%, preferably about 50 to 90 wt%, particularly preferably about 65 to 85 wt%. If the molecular weight is too low, the thickening effect is low, and if the molecular weight is too high, it is difficult to manufacture and is difficult to obtain.If too high a propylene oxide unit content is used, the hydraulic oil has a problem of unpleasant odor. . Further, the blending amount of the high molecular weight polyoxyethylene / oxypropylene copolymer used as the thickener is appropriately about 0.1 to 10 wt%, preferably about 0.5 to 8 wt% based on the final composition.

To the hydraulic oil of the present invention, additives such as ordinary lubricants, antioxidants, rust preventives, anticorrosives, defoamers, pour point depressants, and viscosity index improvers may be added as necessary. it can.

Any lubricant can be used as long as it can be dissolved in the composition of the present invention. Examples thereof include fatty acids such as palmitic acid, stearic acid and oleic acid, lard oil, olive oil, fats such as castor oil and rapeseed oil. Higher alcohols, higher fatty acid esters, mineral oil lubricants, synthetic lubricants,
Tricresyl phosphate / trixylenyl phosphate / monooctyl phosphate / dioctyl phosphate / trioctyl phosphate / trioctyl phosphite / trioctyl thiophosphate / phosphoric acid ester such as tricresyl tricresyl ester / thiophosphoric acid Phosphorus additives of esters, phosphorus-based esters obtained by neutralizing the residual OH groups of these phosphorus additives with amines, hydrocarbon salts such as dioctyl polysulfide, terpene sulfides, terpenes and C _{6 -20} unsaturated hydrocarbons and phosphorus sulfide (P ₂ S ₅ , P ₂ S ₄
Etc.), which are reaction products with sulfur-phosphorus additives, zinc dialkyldithiophosphates, chlorinated hydrocarbon additives such as chlorinated paraffins, sulfide additives such as sulfurized fats and oils, sulfide mineral oils, dimer acid Fatty acid amides such as amides, amine oleate, potassium oleate, aluminum stearate, copper naphthenate, aliphatic soaps such as lead stearate, solid lubricants such as molybdenum dichloride and graphite (which do not dissolve) Dispersed (used in gear oils and cutting oils) Sulfur chloride-based additives that combine sulfur chloride with fatty acids. Lubricants (oiliness improvers, antiwear agents, extreme pressure agents) particularly suitable for hydraulic oils and gear oils are fatty acids, fatty acid soaps, sulfur-based additives, phosphorus-based additives, sulfur-phosphorus-based additives, among the above -Zinc-based additives and fats and oils, and additives particularly suitable for cutting oils are sulfur-based additives, chloride-based additives, fatty acids, oils and fats, fatty acid soaps, and phosphorus-based additives. Any rust preventive and anticorrosive may be used as long as they are soluble in the composition of the present invention, and examples thereof include rosins such as abietic acid, ethanolamines, benzothiazoles, benzotriazoles, amines, amides, and the like. Carboxylic acid soaps such as lead naphthenate and aluminum stearate, calcium sulfonate,
Barium sulfonates and other sulfonic acid soaps, sulfonates, naphthenates, alkenyl succinic acids, polyoxyalkylene alkyl ethers, polyoxyalkylene alkyl phenol ethers, sorbitan fatty acid esters, polyoxyalkylene sorbitan fatty acid esters, polyoxy There are nonionic surfactants such as alkylene esters. Examples of antioxidants include bisphenols such as methylene-4,4-bis (2,6-ditertiary butylphenol), alkylphenols such as ditertiary butylcresol, naphthylamines, zinc diallyldithiophosphate. There are kinds. Examples of the defoaming agent include a silicone-based defoaming agent and a polymethylmethacrylate defoaming agent.

As an example of the amount of these additives added, the lubricant is about 0.
01 ~ 2wt%, antioxidant about 0.01 ~ 1wt%, rust preventive / corrosion inhibitor about 0.01 ~ 0.5wt%, defoamer about 0.0005 ~ 0.01wt%,
Pour point depressant is about 0.01-0.1wt%, viscosity index improver is about
0.01 to 2 wt%.

〔Example〕

 Next, examples and comparative examples of the present invention will be described.

Example 1 Polyethylene glycol having a molecular weight of Mw200 (referred to as PEG200) 96.9 wt%, polyoxyalkylene glycol (polyethylene-oxypropylene copolymer, content of ethylene oxide unit 75 wt%, molecular weight Mw≈15,000, trade name of NOF Corporation) : Unilube 75DE3800) 2.5 wt%, 2,6-ditertiary butyl-paracresol 0.5 as an additive
wt%, alkenylsuccinic acid 0.05 wt% and benztriazole 0.05 wt% were mixed to prepare a hydraulic oil composition.

Measurement of properties of this hydraulic oil composition, forced deterioration test (JIS K2
514 Based on the oxidation stability test of lubricating oil, only the point that water is not added to the sample oil (commonly called the waterless TOST method) has been changed. ), And a vane pump test (ASTM D2882 vane pump test) was performed. The results are as shown in the following table.

Example 2 93.9% by weight of polyethylene glycol having a molecular weight of Mw200, 5.5% by weight of the same polyoxyalkylene glycol as in Example 1,
A hydraulic oil composition was prepared by mixing the same additives as in Example 1. As a result of conducting the test of the same measurement items as in Example 1, the values shown in the following table were obtained.

Example 3 Polyethylene glycol having a molecular weight of Mw300 (PEG300) 93.4w
t%, polyoxyalkylene glycol (polyoxyethylene / oxypropylene copolymer, content of ethylene oxide unit 50 wt%, number average molecular weight 15,000) 6.0 wt%,
A hydraulic oil composition was prepared by mixing the same additives as in Example 1. As a result of conducting the test of the same measurement items as in Example 1, the values shown in the following table were obtained.

Comparative Example 1 Polyether (polyoxyethylene / oxypropylene copolymer, content of ethylene oxide unit 50 wt%, molecular weight Mw≈1,000, NOF Corporation trade name: Unilube 50MB
-11) A hydraulic oil composition was prepared by mixing 99.4 wt% of the same additive as in Example 1. As a result of conducting the test of the same measurement items as in Example 1, the values shown in the following table were obtained.

Comparative Example 2 Mineral oil lubricating oil (viscosity 46 cSt (40 ° C)) 99.4 wt%, Example 1
A hydraulic oil composition was prepared by mixing the same additives as described above. As a result of conducting the test of the same measurement items as in Example 1, the values shown in the following table were obtained.

[Effects of the Invention] Since the hydraulic oil composition of the present invention uses polyethylene glycol as a base oil as described above, it is unpleasant not only when the hydraulic oil is fresh, but also when the hydraulic oil is deteriorated due to long-term use. The odor can be minimized. Therefore, the hydraulic oil composition of the present invention can be used not only as an industrial lubricating oil, but also as a hydraulic oil for hydraulic systems used in a living environment such as hydraulic systems for homes, homes, and public facilities. It is a hydraulic oil that has been improved and has improved work / living environment and pollution problems.

In addition, since both the base oil and the thickener are water-soluble, there is an advantage that leaked operating oil can be easily removed with a cloth or waste cloth, and even if it adheres to clothes, it can be removed by washing with water. Especially, it will be a great advantage in spreading the hydraulic system to homes and public facilities.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location C10N 30:00 G 30:02 40:08 (72) Inventor Yoshiaki Kurachi 6 Nononoshita, Nagareyama City, Chiba Prefecture −613−99 (72) Inventor Yasuo Iwamiya 8-chome 8-27 Hanada, Koshigaya City, Saitama Prefecture (72) Inventor Yuichi Takagi 732 Hanaguri Town, Soka City, Saitama Cosmo Oil Company Housing 4-206 (56) References JP 48 -55185 (JP, A) JP 58-29898 (JP, A) JP 54-105653 (JP, A) JP 54-129256 (JP, A)

Claims (1)

[Claims] 1. A base oil consisting of polyethylene glycol having a number average molecular weight of 100 to 300 and 90 to 99.9 wt% and a number average molecular weight of 3,000.
A hydraulic fluid composition comprising 0 to 200,000 polyoxyethylene / oxypropylene copolymer 10 to 0.1 wt% as a main component.