JP2009161664A - Flame-retardant hydraulic fluid composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flame-retardant hydraulic fluid composition which is best for applications which have a high risk of fire and are used at high temperature under high pressure, can be applied to a high pressure pump, is excellent in abrasion resistance, seizure resistance and sludge suppression performance, and can be used for a long period of time. <P>SOLUTION: The flame-retardant hydraulic fluid composition includes: (A) at least one base oil selected from the group consisting of synthetic esters and greases; (B) bis(4-dialkylaminophenyl)methane antioxidant represented by formula (1) in an amount of 0.01-5.0 mass% based on the total amount of the composition; and (C) at least one antiwear agent selected from a sulfur-containing phosphoric acid ester, an alkyl acid phosphate, an alkyl acid phosphate amine salt, and a phosphite in an amount of 0.001-5 mass% based on the total amount of the composition. The composition has a flash point of not less than 280°C. In the formula, R<SP>1</SP>, R<SP>2</SP>, R<SP>3</SP>, and R<SP>4</SP>may be the same or different from each other and are each a 1-6C alkyl group. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a flame retardant hydraulic fluid composition, particularly high risk of fire occurrence, such as aluminum die-cast extrusion machine or steelworks premises work, optimal for use in high temperature and high pressure, and high pressure The present invention relates to a flame retardant hydraulic fluid composition that is applicable to a pump, is excellent in wear resistance, seizure resistance, sludge suppression performance, and can be used for a long period of time.

  Conventionally, hydraulic fluids used in places where there is a high risk of fire, such as aluminum die-cast extrusion processing machines or steelworks premises work, are made of flame retardant hydraulic fluids such as water glycols or fatty acid esters (liquids). ) Was used. Among them, water glycol is mainly used in places where there are regulations for the fourth oils due to regulations of the Fire Service Law, but it has drawbacks in terms of the complexity of use liquid management and wear resistance. However, as a result of the revision of the Fire Service Act in 2002, hydraulic oils based on fatty acid esters with a flash point of 250 ° C. or higher have been exempted from the Fire Service Act, and their uses have expanded.

The performance of the fatty acid ester varies depending on the composition of the fatty acid constituting the ester, and the ester of saturated fatty acid is excellent in oxidation stability. However, saturated fatty acids are expensive because they are produced by synthesizing from petroleum raw materials or hydrogenating unsaturated fatty acids obtained from animal and vegetable oils, and are not friendly to the global environment. For this reason, natural synthetic esters and fats and oils using fatty acids mainly composed of unsaturated fatty acids obtained from animal and plant oils that are environmentally friendly and advantageous in terms of cost are also used (Patent Documents 1 to 3). 3).
JP 2001-214187 A Japanese Patent No. 3548591 Japanese Patent No. 2888747

  On the other hand, the hydraulic system has recently been increased in pressure and maintenance-free, and hydraulic oil used in such an environment has been required to have a long life and excellent wear resistance. However, natural synthetic esters made from natural materials such as animal and vegetable oils are mainly fatty acids, which are unsaturated fatty acids. The disadvantage was that it was significantly inferior to synthetic esters and synthetic hydrocarbon oils.

  In conventional mineral oil-based hydraulic fluids or synthetic hydrocarbon-based hydraulic fluids, phenol-based antioxidants, amine-based antioxidants, ZnDTP (zinc dialkyldithiophosphate) and the like have been used as additives for oxidation resistance stability. However, ester hydraulic oils composed of saturated fatty acids or unsaturated fatty acids, when blended with conventional phenolic antioxidants and amine antioxidants, are prone to accumulation of sludge because the solubility of the generated sludge is poor, There is a problem of causing various problems. In particular, when a synthetic ester using an unsaturated fatty acid having inferior oxidative stability or animal or vegetable oil or fat is used as a base oil, the tendency is remarkable. Synthetic esters using unsaturated fatty acids as raw materials and additives that effectively act on animal and vegetable oils have not yet been found. Conventionally, synthetic esters using saturated fatty acids that have adverse effects on the global environment and are expensive. Or synthetic ester or animal and vegetable oils and fats made from unsaturated fatty acids with a short oil exchange interval had to be selected.

In addition, wear resistance additives such as ZnDTP (zinc dialkyldithiophosphate) and aromatic phosphate esters have been used in conventional mineral oil-based hydraulic fluids. However, when ester is used as a base oil, since the adsorption activity of the ester itself is high, there has been a problem that the effects of these additives are hardly exhibited as compared with mineral oil. For example, TCP (tricresyl phosphate), which is a typical phosphorus wear inhibitor, hardly exhibits its wear resistance effect in fatty acid esters.
As described above, the conventional technology is to develop a flame retardant hydraulic oil with long life and excellent wear resistance using synthetic esters and animal and vegetable oils and fats that are environmentally friendly and use relatively inexpensive natural raw materials. Was in a very difficult situation.

Ester oil has come to be used as a flame retardant hydraulic oil, but esters composed of unsaturated fatty acids have very poor oxidation stability. However, conventional phenol-based antioxidants and amine-based antioxidants that have been used for mineral oils and synthetic hydrocarbon oils do not provide sufficient antioxidant effect and wear resistance for ester oils.
The present invention has been made in view of such circumstances, and in synthetic esters or animal and vegetable oils and fats obtained from raw materials mainly composed of unsaturated fatty acids, it has sufficient antioxidant performance and wear resistance. The object is to provide a long-life, flame-retardant hydraulic fluid that supports high pressure and maintenance-free hydraulic systems.

  As a result of intensive studies on the above problems, the present inventors have found that specific amine-based antioxidants and specific compounds for synthetic esters and / or fats and oils, especially synthetic esters mainly composed of unsaturated fatty acids obtained from natural raw materials. The present inventors have found that the above-mentioned problems can be solved by blending the phosphorus compound, and have completed the present invention.

〔Ｒ^１，Ｒ^２，Ｒ^３及びＲ^４は、それぞれ同一でも異なっていてもよく、炭素数１〜６のアルキル基である。〕 That is, the present invention provides (B) a bis (4-dialkylaminophenyl) methane-based antioxidant represented by the formula (1) on at least one base oil selected from the group consisting of synthetic esters and fats and oils. 0.01 to 5.0% by mass based on the total amount of the composition, and (C) at least one type of wear selected from sulfur-containing phosphate esters, acidic phosphate esters, acidic phosphate amine salts and phosphite esters The present invention relates to a flame retardant hydraulic fluid composition comprising 0.001 to 5% by mass of an inhibitor based on the total amount of the composition and having a flash point of 280 ° C. or higher.

[R ¹ , R ² , R ³ and R ⁴ may be the same as or different from each other, and are each an alkyl group having 1 to 6 carbon atoms. ]

Further, the present invention is characterized in that the fatty acid constituting the synthetic ester is a fatty acid obtained from an animal and plant raw material, and the ratio of the unsaturated fatty acid to the fatty acid constituting the synthetic ester is 30 mol% or more. The present invention relates to a flame retardant hydraulic fluid composition.
Furthermore, the present invention relates to the flame retardant hydraulic fluid composition as described above, further comprising 0.01 to 5% by mass of a phenolic antioxidant as an antioxidant based on the total amount of the composition.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the flame retardant hydraulic fluid composition excellent in oxidation resistance stability and abrasion resistance in the ester oil of fatty acid mainly composed of unsaturated fatty acid. In addition, it is possible to provide a flame retardant hydraulic fluid composition having an acceptable stage of 10 or more in the FZG gear test or a biodegradation rate of 60% or more according to the OECD301C method.

Hereinafter, preferred embodiments of the present invention will be described in detail.
As the base oil used in the flame-retardant hydraulic fluid composition of the present invention, at least one selected from synthetic esters of fatty acids mainly composed of unsaturated fatty acids and natural animal and plant oils and fats is used as the base oil. Examples thereof include polyol esters, diesters, various vegetable oils and fats, animal fats and the like. Of these, esters such as polyol esters, rapeseed oil, sunflower oil, and soybean oil having a high oleic acid ratio are preferable, and those having a kinematic viscosity at 40 ° C. of 10 to 200 mm ² / s and a flash point of 280 ° C. or higher are particularly preferable. .

  Examples of synthetic esters include fatty acid esters, dibasic acid esters, polyol esters, complex esters, aromatic esters, carbonate esters, and mixtures thereof.

  Fatty acid esters include palmitoyl acid, oleic acid, vaccenic acid, linoleic acid, linolenic acid, elestearic acid, 8,11-icosadienoic acid and the like, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid A saturated fatty acid having a linear or branched alkyl group having 5 to 19 carbon atoms, such as decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, and nonadecanoic acid Carbon number having a linear or branched alkyl group such as methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, etc. Esters and mixtures thereof with monohydric alcohols to 15 is preferably used. Specifically, fatty acid esters such as oleyl stearate and oleyl laurate are preferred.

  As the dibasic acid ester, dibasic acid having 5 to 10 carbon atoms such as glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and the linear or branched alkyl group described in the fatty acid ester Are preferably used, and more specifically, for example, ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, diester -2-ethylhexyl sebacate, and mixtures thereof.

As the polyol ester, an ester of a polyol having 3 to 20 diols or hydroxyl groups and a fatty acid having 1 to 24 carbon atoms is preferably used.
Specific examples of the diol include ethylene glycol, 1,3-propanediol, propylene glycol, 1,4-butanediol, 1,2-butanediol, 2-methyl-1,3-propanediol, 1,5 -Pentanediol, neopentyl glycol, 1,6-hexanediol, 2-ethyl-2-methyl-1,3-propanediol, 1,7-heptanediol, 2-methyl-2-propyl-1,3-propane Diol, 2,2-diethyl-1,3-propanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, etc. Is mentioned.

Specific examples of the polyol include, for example, trimethylolethane, trimethylolpropane, trimethylolbutane, di- (trimethylolpropane), tri- (trimethylolpropane), pentaerythritol, di- (pentaerythritol), tri- (Pentaerythritol), glycerin, polyglycerin (2-20 mer of glycerin), 1,3,5-pentanetriol, sorbitol, sorbitan, sorbitol glycerin condensate, polyhydric alcohol such as adonitol, arabitol, xylitol, mannitol, Xylose, arabinose, ribose, rhamnose, glucose, fructose, galactose, mannose, sorbose, cellobiose, maltose, isomaltose, trehalose, sucrose, raffino Scan, gentianose, sugars such as melezitose, and their partially etherified products and methyl glucosides (glycosides) and the like.
Among these, polyols are more excellent in hydrolytic stability, so neopentyl glycol, trimethylol ethane, trimethylol propane, trimethylol butane, di- (trimethylol propane), tri- (trimethylol propane), penta Hindered alcohols such as erythritol and di- (pentaerythritol) are preferred.

  Examples of the fatty acid of the polyol ester include unsaturated fatty acids described in the fatty acid esters and saturated fatty acids having a linear or branched alkyl group having 5 to 19 carbon atoms, and particularly unsaturated fatty acids described in the fatty acid esters. Is preferably used. Or the neo acid etc. whose (alpha) carbon atom is quaternary are mentioned. Specific examples of branched saturated fatty acids include isopentanoic acid (3-methylbutanoic acid), 2-methylhexanoic acid, 2-ethylpentanoic acid, 2-ethylhexanoic acid, and 3,5,5-trimethylhexanoic acid. Can be mentioned.

  Specific examples of preferable polyol esters include valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, oleic acid, isopentanoic acid, 2-methylhexanoic acid, 2-ethylpentanoic acid, and 2-ethylhexanoic acid. A diester of one or more fatty acids selected from 3,5,5-trimethylhexanoic acid and each polyol of neopentyl glycol, trimethylol ethane, trimethylol propane, trimethylol butane and pentaerythritol, Triesters and tetraesters are mentioned.

  The ester with two or more fatty acids may be a mixture of two or more esters of one fatty acid and a polyol, or may be an ester of two or more mixed fatty acids and a polyol.

  Among polyol esters, since they are more excellent in hydrolytic stability, neopentyl glycol, trimethylol ethane, trimethylol propane, trimethylol butane, di- (trimethylol propane), tri- (trimethylol propane), penta More preferred are esters of hindered alcohols such as erythritol, di- (pentaerythritol), tri- (pentaerythritol), and even more preferred are esters of neopentyl glycol, trimethylol ethane, trimethylol propane, trimethylol butane and pentaerythritol. The ester of trimethylolpropane and pentaerythritol is most preferred because it is particularly excellent in hydrolysis stability. Specifically, trimethylolpropane oleate, pentaerythritol oleate, and the like are preferably used.

  The polyol ester may be a partial ester in which some hydroxyl groups remain without esterification of all hydroxyl groups of the polyol, or may be a complete ester in which all hydroxyl groups are esterified, A mixture of a partial ester and a complete ester may be used, but a complete ester is preferred.

  Complex esters are esters of fatty acids and dibasic acids with monohydric alcohols and polyols. Examples of fatty acids, dibasic acids, monohydric alcohols, and polyols are given in the description of dibasic acid esters and polyol esters. You can use the same ones.

As an aromatic ester, ester of 1-6 valent, preferably 1-4 valent, more preferably 1-3 valent aromatic carboxylic acid and C1-C18, preferably 1-12 aliphatic alcohol, etc. Is used. Specific examples of the monovalent to hexavalent aromatic carboxylic acid include benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, and mixtures thereof. Moreover, as a C1-C18 aliphatic alcohol, the C1-C15 monohydric alcohol which has the linear or branched alkyl group as described in the said fatty acid ester, a linear or branched hexadecanol is mentioned. , Linear or branched heptadecanol, linear or branched octadecanol, and mixtures thereof.
Specific examples of the aromatic ester include dibutyl phthalate, di (2-ethylhexyl) phthalate, dinonyl phthalate, didecyl phthalate, didodecyl phthalate, ditridecyl phthalate, tributyl trimellitic acid, trimethyl trimellitic acid ( 2-ethylhexyl), trinonyl trimellitic acid, tridecyl trimellitic acid, tridodecyl trimellitic acid, tritridecyl trimellitic acid, and the like. Of course, when a divalent or higher valent aromatic carboxylic acid is used, it may be a simple ester composed of one kind of aliphatic alcohol, or a complex ester composed of two or more kinds of aliphatic alcohol. May be.

The carbonate ester is a compound having a carbonate ester structure in the molecule. One carbonate ester structure or a plurality of carbonate ester structures may be included in one molecule.
As alcohol which comprises carbonate ester, the above-mentioned aliphatic alcohol, polyol, etc. can be used, and what added polyglycol to polyglycol and polyol can also be used. Moreover, you may use what used carbonic acid and a fatty acid, and / or a dibasic acid.

As a matter of course, the ester referred to in the present invention may be a single ester having a single structure or a mixture of two or more esters having different structures.
Among these ester base oils, a polyol ester is preferable because of excellent hydrolysis stability.
In the present invention, one of the above ester base oils may be used alone, or two or more may be used in combination.

  Examples of the oil used as the base oil of the flame retardant hydraulic fluid composition of the present invention include natural animal and vegetable oils and fats, such as rapeseed oil, sunflower oil, soybean oil, castor oil, coconut oil, corn oil, and cottonseed oil. Olive oil, rice bran oil, coconut oil, palm oil, palm kernel oil, peanut oil, tall oil, beef tallow, lard, or hydrogenated products thereof. Among the oils and fats, hyoleic acid type fats and oils having a high proportion of unsaturated fatty acids, particularly oleic acid, among fatty acids constituting the ester are preferable, and hyoleinized vegetable oil having a higher proportion of oleic acid is more preferable.

  As the base oil of the flame retardant hydraulic oil composition of the present invention, one kind selected from the group consisting of the above-mentioned synthetic ester and oil may be used alone, or two or more kinds may be used in combination.

In the synthetic ester and / or fat and oil, the constituent fatty acid may be a saturated fatty acid, an unsaturated fatty acid, a linear fatty acid, or a branched fatty acid, but the formula (1) used as the component (B) From the viewpoint of the effect of the bis (4-dialkylaminophenyl) methane-based antioxidant represented by (), a higher unsaturated fatty acid content is preferred. The ratio of the unsaturated fatty acid to the fatty acid constituting the ester is 30 mol% or more, preferably 50 mol% or more, more preferably 70 mol% or more.
When the ratio of unsaturated fatty acid in the fatty acid constituting the ester is less than 30 mol%, even if the component (B) is blended, the effect of suppressing the increase in viscosity and the increase in acid value is obtained at the initial stage of use of the hydraulic fluid. However, as the use proceeds, the deteriorated product tends to become sludge suddenly, and troubles may occur in the hydraulic system.

The kinematic viscosity of these base oils is not particularly limited and is arbitrary, but is usually 40 ° C. from the viewpoint of excellent flame retardancy, wear resistance, seizure resistance, and low friction loss due to stirring resistance. The kinematic viscosity in is preferably 10 to 200 mm ² / s, more preferably 15 to 150 mm ² / s, and still more preferably 20 to 100 mm ² / s. Moreover, although the viscosity index is also arbitrary, from the viewpoint of maintaining an oil film at a high temperature, the viscosity index is usually preferably 80 to 500, more preferably 100 to 300. Furthermore, although the pour point is also arbitrary, it is preferably −5 ° C. or less, more preferably −15 ° C. or less from the viewpoint of pump startability in winter.

The flame-retardant hydraulic fluid composition of the present invention contains a bis (4-dialkylaminophenyl) methane-based antioxidant represented by the general formula (1) as an essential component (B).

In the general formula (1), R ¹ , R ² , R ³ and R ⁴ may be the same or different and each represents a linear or branched alkyl group having 1 to 6 carbon atoms. When the number of carbon atoms in the alkyl group of R ¹ , R ² , R ³ and R ⁴ exceeds 6, the proportion of the functional group in the molecule is reduced, which may adversely affect the antioxidant effect. Specific examples of the alkyl group represented by R ¹ , R ² , R ³ and R ⁴ include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group and the like (these alkyl groups are Linear or branched).

Among the compounds represented by the general formula (1), R ¹ , R ² , R ³ and R ⁴ are a methyl group, an ethyl group, or a carbon number of 3 to 4 because a more excellent antioxidant effect can be obtained. A branched alkyl group is preferred, and a methyl group or an ethyl group is most preferred.

The upper limit of the content of the component (B) in the flame retardant hydraulic fluid composition of the present invention is 5% by mass, preferably 2% by mass, more preferably 1.5% by mass based on the total amount of the composition. is there. When the content exceeds 5% by mass, sludge is generated, which is not preferable.
On the other hand, the lower limit of the content of component (B) is 0.01% by mass, preferably 0.05% by mass, more preferably 0.1% by mass, based on the total amount of the composition. When the content of the component (B) is less than 0.01% by mass, the antioxidant effect is insufficient, which is not preferable.

  As the bis (4-dialkylaminophenyl) methane antioxidant represented by the general formula (1), a commercially available product may be used, or a synthesized product may be used.

  The flame-retardant hydraulic fluid composition of the present invention comprises (C1) a sulfur-containing phosphate ester, (C2) an acidic phosphate ester, (C3) an acidic phosphate amine salt, and (C4) as the component (C). Contains at least one antiwear agent selected from the group consisting of phosphites.

  (C1) Specific examples of the sulfur-containing phosphate ester include trialkyl phosphorothioates, trioleyl phosphorothioates, triphenyl phosphorothioates, tricresyls having an alkyl group of 4 to 18 carbon atoms. Phosphorothioate, trixylenyl phosphorothioate, cresyl diphenyl phosphorothioate, xylenyl diphenyl phosphorothioate, tris (n-propylphenyl) phosphorothioate, tris (isopropylphenyl) phosphorothioate , Tris (n-butylphenyl) phosphorothioate, tris (isobutylphenyl) phosphorothionate, tris (s-butylphenyl) phosphorothionate, tris (t-butylphenyl) phosphorothionate And the like.

  (C2) Specific examples of the acidic phosphate ester include alkyl acid phosphates having an alkyl group having 7 to 18 carbon atoms, dialkyl acid phosphates and dioleyl acid phosphates having an alkyl group having 4 to 18 carbon atoms, and the like. Is mentioned.

  (C3) As the acidic phosphate amine salt, specifically, the acidic phosphate ester, an amine having an alkyl group having 1 to 8 carbon atoms, an amine having two alkyl groups having 1 to 8 carbon atoms, And a salt with an amine having 3 alkyl groups having 1 to 8 carbon atoms.

  Specifically, as (C4) phosphite, dialkyl phosphite, dioleyl phosphite, diphenyl phosphite, dicresyl phosphite having 2 to 4 carbon atoms and 12 to 12 carbon atoms are used. And trialkyl phosphites having 3 alkyl groups, trioleyl phosphite, triphenyl phosphite, and tricresyl phosphite.

  As (C) component used by this invention, since the effect in synthetic ester and fats and oils is high especially, (C1) sulfur containing phosphate ester, (C2) acidic phosphate ester, (C3) acidic phosphate ester Amine salts are preferably used.

  The upper limit of the content of the component (C) in the flame-retardant hydraulic fluid composition of the present invention is 5% by mass, preferably 2% by mass, more preferably 1.5% by mass based on the total amount of the composition. is there. When the content exceeds 5% by mass, the thermal stability is inferior and sludge is generated, which is not preferable. On the other hand, the lower limit of the content of the component (C) is 0.001% by mass, preferably 0.005% by mass, more preferably 0.01% by mass based on the total amount of the composition. When the content of the component (C) is less than 0.001% by mass, the wear resistance and seizure resistance are insufficient, which is not preferable.

  The flame-retardant hydraulic fluid composition of the present invention can add higher antioxidant properties and sludge suppressive properties by using a phenolic antioxidant in combination. As the phenolic antioxidant, any alkylphenolic compound used as an antioxidant for lubricating oil can be used, and is not particularly limited. For example, hindered phenols such as alkylphenols and bisphenols The type is preferred, and those containing a sulfide group and an ester bond in the molecule are also preferably used.

  The upper limit of the content of the phenolic antioxidant in the flame retardant hydraulic fluid composition of the present invention is preferably 5% by mass, more preferably 2% by mass, and even more preferably 1.5% by mass based on the total amount of the composition. %. When the content exceeds 5% by mass, sludge is generated, which is not preferable. On the other hand, the lower limit of the content of the phenolic antioxidant is preferably 0.01% by mass, more preferably 0.05% by mass, and still more preferably 0.1% by mass based on the total amount of the composition. When the content of the phenolic antioxidant is less than 0.01% by mass, the antioxidant effect by the combined use is not added, which is not preferable.

  As the phenolic antioxidant, any alkylphenolic compound used as an antioxidant for lubricating oil can be used, and is not particularly limited. For example, the following general formula (2) or general formula One or more alkylphenol compounds selected from the compounds represented by (3) are preferred.

上記（２）式中、Ｒ^５は炭素数１〜４のアルキル基を示し、Ｒ^６は水素原子又は炭素数１〜４のアルキル基を示し、Ｒ^７は水素原子、炭素数１〜４のアルキル基、下記の一般式（ｉ）で表される基又は下記の一般式（ii）で表される基を示す。

In the formula (2), R ⁵ represents an alkyl group having 1 to 4 carbon atoms, R ⁶ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ⁷ represents a hydrogen atom, or an alkyl group having 1 to 4 carbon atoms. An alkyl group, a group represented by the following general formula (i) or a group represented by the following general formula (ii) is shown.

In the above formula (i), ^{R 8} is an alkylene group having 1 to 6 carbon atoms, ^{R 9} represents an alkyl or alkenyl group having 1 to 24 carbon atoms.
In the formula (ii), R ¹⁰ represents an alkylene group having 1 to 6 carbon atoms, R ¹¹ represents an alkyl group having 1 to 4 carbon atoms, and R ¹² represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. N represents an integer of 0 or 1.

上記（３）式中、Ｒ¹³及びＲ¹⁷は、それぞれ個別に、炭素数１〜４のアルキル基を示し、Ｒ¹⁴及びＲ¹⁸は、それぞれ個別に、水素原子又は炭素数１〜４のアルキル基を示し、Ｒ¹⁵及びＲ¹⁶は、それぞれ個別に、炭素数１〜６のアルキレン基を示し、Ｙは炭素数１〜１８のアルキレン基又は下記の一般式（iii）で表される基を示す。
−Ｒ¹⁹−Ｓ−Ｒ²⁰− （iii）
上記式（iii）中、Ｒ¹⁹及びＲ²⁰は、それぞれ個別に、炭素数１〜６のアルキレン基を示す。

In the above formula (3), R ¹³ and R ¹⁷ each independently represent an alkyl group having 1 to 4 carbon atoms, and R ¹⁴ and R ¹⁸ each independently represent a hydrogen atom or an alkyl having 1 to 4 carbon atoms. R ¹⁵ and R ¹⁶ each independently represents an alkylene group having 1 to 6 carbon atoms, and Y represents an alkylene group having 1 to 18 carbon atoms or a group represented by the following general formula (iii). Show.
—R ¹⁹ —S—R ²⁰ — (iii)
In the formula (iii), R ¹⁹ and R ²⁰ are each independently an alkylene group having 1 to 6 carbon atoms.

In formula (2), ^{R 5} represents an alkyl group having 1 to 4 carbon atoms. Of these, a tert-butyl group is preferred because it is more excellent in sludge resistance. R ⁶ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Among these, a hydrogen atom, a methyl group, or a tert-butyl group is preferable because it is more excellent in sludge resistance. R ⁷ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a group represented by the above formula (i), or a group represented by the above formula (ii). The alkyl group having 1 to 4 carbon atoms represented by R ⁷ is preferably a methyl group or an ethyl group from the viewpoint of superior sludge resistance.

In the case where R ⁷ in the general formula (2) is a group represented by the formula (i), the alkylene group having 1 to 6 carbon atoms represented by R ⁸ in the formula (i) may be linear or branched. Specifically, for example, a methylene group, a methylmethylene group, an ethylene group (dimethylene group) and the like are more preferable.
On the other hand, R ⁹ in the formula (i) represents an alkyl group having 1 to 24 carbon atoms (which may be linear or branched) or an alkenyl group (which may be linear or branched, and a double bond position). Is also optional). Among these, R ⁹ is preferably an alkyl group having 4 to 18 carbon atoms, more preferably a linear or branched alkyl group having 6 to 12 carbon atoms, and more preferably 6 carbon atoms. Particularly preferred are -12 branched alkyl groups.

Among the phenolic compounds represented by the general formula (2), as a compound when R ⁷ is a group represented by the formula (i), R ⁸ in the formula (i) is an alkylene having 1 to 2 carbon atoms. R ⁹ is more preferably a linear or branched alkyl group having 6 to 12 carbon atoms, R ⁸ in formula (i) is an alkylene group having 1 to 2 carbon atoms, and R ⁹ Is particularly preferably a branched alkyl group having 6 to 12 carbon atoms. In the case where R ⁷ in the general formula (2) is a group represented by the formula (ii), R ¹⁰ in the formula (ii) represents an alkylene group having 1 to 6 carbon atoms. The alkylene group may be linear or branched, and specific examples include various alkylene groups exemplified above for R ⁸ . Among these, as R ¹⁰ , an alkylene group having 1 to 3 carbon atoms, specifically, for example, methylene group, methylmethylene group, ethylene group (dimethylene group), ethylmethylene group, propylene group (methylethylene group), trimethylene Groups and the like are more preferable.

R ¹¹ in formula (ii) represents an alkyl group having 1 to 4 carbon atoms. Specifically, a tert-butyl group is preferable from the viewpoint of excellent sludge resistance. Moreover, as R < ¹² >, although a hydrogen atom or a C1-C4 alkyl group as mentioned above is mentioned, a hydrogen atom, a methyl group, or a tert-butyl group is preferable from the point which is excellent in sludge resistance. N in the formula (ii) represents an integer of 0 or 1. When n is 0, it takes a biphenyl structure in which two benzene rings are directly bonded.

In the general formula (2), as described above, R ⁷ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a group represented by the above formula (i), or a group represented by the above formula (ii). Among these, an alkyl group having 1 to 4 carbon atoms or a group represented by the above formula (ii) is preferable, and a methyl group, an ethyl group, or a group represented by the above formula (ii), ^A group in which ¹⁰ is an alkylene group having 1 to 3 carbon atoms, R ¹¹ is a tert-butyl group, R ¹² is a hydrogen atom, a methyl group or a tert-butyl group, and n is an integer of 0 or 1 It is more preferable that

As the compound represented by the general formula (2), various compounds are included as described above, and the compounds in the case where R ⁷ is an alkyl group having 1 to 4 carbon atoms are exemplified among these compounds. 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butyl-4-ethylphenol, etc .; as a compound when R ⁷ is a group represented by formula (i) N-hexyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) acetate, isohexyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) propionate, (3,5-di-tert -Butyl-4-hydroxyphenyl) acetate n-heptyl, (3,5-di-tert-butyl-4-hydroxyphenyl) propionate 2-ethylhexyl, (3,5-di-ter - butyl-4-hydroxyphenyl) isododecyl propionate; as compound when ^{R 7} is a group represented by the formula (ii), bis (3,5-di -tert- butyl-4-hydroxyphenyl) Bis (3,5-di-tert-butyl-4-hydroxyphenyl) methane, and the like; and mixtures thereof.

On the other hand, in the above general formula (3), R ¹³ and R ¹⁷ are each independently an alkyl group having 1 to 4 carbon atoms. Specifically, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group and the like are shown. A tert-butyl group is preferred. R ¹⁴ and R ¹⁸ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Examples of such an alkyl group include the groups described above. Among these, a hydrogen atom, a methyl group, or a tert-butyl group is preferable because they are more excellent in sludge resistance. Further, the alkylene group having 1 to 6 carbon atoms represented by R ¹⁵ and R ¹⁶ may be linear or branched, and specifically, various alkylene groups described above for R ⁸ individually. Is mentioned. R ¹⁵ and R ¹⁶ are each independently from the viewpoints that the compound represented by the general formula (3) can be produced by a reaction process with few compounds and that the raw materials are easy to obtain. An alkylene group, specifically, for example, a methylene group, a methylmethylene group, an ethylene group (dimethylene group) and the like are more preferable.

  In the general formula (3), Y represents an alkylene group having 1 to 18 carbon atoms or a group represented by the above formula (iii). The alkylene group having 1 to 18 carbon atoms represented by Y may be linear or branched. An alkylene group having 1 to 6 carbon atoms is more preferable from the viewpoint of easy availability of raw materials, and an ethylene group (dimethylene group), trimethylene group, linear butylene group (tetramethylene group), linear pentylene group (pentamethylene group), A linear alkylene group having 2 to 6 carbon atoms such as a linear hexylene group (hexamethylene group) is particularly preferred.

Of the alkylphenols represented by the general formula (3), a compound represented by the following formula (4) is particularly preferable as a compound when Y is an alkylene group having 1 to 18 carbon atoms.

In the case where Y in the general formula (3) is a group represented by the formula (iii), the alkylene group having 1 to 6 carbon atoms represented by R ¹⁹ and R ²⁰ in the formula (iii) is The chain may be branched or branched, and specific examples include various alkylene groups as described above for R ⁸ individually. As R ¹⁹ and R ²⁰ , among these, since raw materials for producing the compound of the general formula (3) are easy to obtain, each independently an alkylene group having 1 to 3 carbon atoms, specifically, for example, More preferred are a methylene group, a methylmethylene group, an ethylene group (dimethylene group), an ethylmethylene group, a propylene group (methylethylene group), a trimethylene group, and the like.

Among the alkylphenols represented by the general formula (3), a compound represented by the following formula (5) is particularly preferable as a compound when Y is a group represented by the formula (iii).

  In the present invention, as described above, it is possible to oxidize only by blending the component (B), the component (C), and further the phenolic antioxidant with at least one base oil selected from the group consisting of synthetic esters and fats and oils. Flame retardant hydraulic fluid with excellent anti-performance and wear resistance can be obtained, but for the purpose of further improving its performance, other antioxidants, rust inhibitors, metal deactivators, Various additives typified by antiwear agents, viscosity index improvers, pour point depressants, antifoaming agents, demulsifiers, stick slip inhibitors, oil agents and the like may be contained alone or in combination.

  In addition to the amine-based antioxidant of component (B), other amine-based antioxidants may be used in combination. Typical amine antioxidants include phenyl-α-naphthylamines represented by the following formula (6) or p, p'-dialkylated diphenylamine represented by the following formula (7).

In the general formula (6), R ²¹ represents a hydrogen atom or an alkyl group having 1 to 16 carbon atoms.
In General formula (7), R < ²² > and R < ²³ > show a C1-C16 alkyl group each independently.

Among the compounds represented by the general formula (6), when R ²¹ is an alkyl group, a more excellent sludge generation suppressing effect can be obtained. Therefore, R ²¹ is a branched alkyl group having 8 to 16 carbon atoms. Further, a branched alkyl group having 8 to 16 carbon atoms derived from an oligomer of an olefin having 3 or 4 carbon atoms is more preferable. Specific examples of the olefin having 3 or 4 carbon atoms include propylene, 1-butene, 2-butene and isobutylene, but propylene or isobutylene is preferable in order to obtain a more excellent sludge formation suppressing effect. In order to obtain a further excellent sludge generation inhibitory effect, R ²¹ is a branched octyl group derived from an isobutylene dimer, a branched nonyl group derived from a propylene trimer, or an isobutylene trimer. A branched dodecyl group derived from a propylene tetramer, a branched dodecyl group derived from a propylene tetramer, or a branched pentadecyl group derived from a propylene pentamer is more preferred, and a branch derived from a dimer of isobutylene. A branched dodecyl group derived from a branched octyl group, a trimer of isobutylene or a branched dodecyl group derived from a tetramer of propylene is more preferred, and a branched dodecyl group is most preferred.

R ²² and R ²³ of p, p′-dialkyldiphenylamine represented by the general formula (7) are each independently a branched alkyl group having 3 to 16 carbon atoms in order to obtain a more excellent sludge formation inhibiting effect. Further, a branched alkyl group having 3 to 16 carbon atoms derived from an olefin having 3 or 4 carbon atoms or an oligomer thereof is more preferable. Specific examples of the olefin having 3 or 4 carbon atoms include propylene, 1-butene, 2-butene, and isobutylene, and propylene or isobutylene is preferable in order to obtain a more excellent sludge generation suppressing effect.
Further, R ²² or R ²³ is most preferably a tert-butyl group derived from isobutylene or a branched octyl group derived from a dimer of isobutylene in order to obtain a better antioxidant effect.

  As the p, p'-dialkyldiphenylamine represented by the general formula (7), a commercially available product or a synthesized product may be used. Similar to the phenyl-α-naphthylamine represented by the general formula (6), the synthesized product is a halogenated alkyl compound having 1 to 16 carbon atoms and diphenylamine, or an olefin having 2 to 16 carbon atoms, or having 2 to 16 carbon atoms. Although it can be easily synthesized by reacting an olefin or an oligomer thereof with diphenylamine using a Friedel-Crafts catalyst, any synthesis method may be used.

  (B) As for the compounding quantity of amine antioxidant other than a component, 0.001-2.0 mass% is preferable on the basis of the composition whole quantity, More preferably, it is 0.05-1.5 mass%, Most preferably, it is 0. .1 to 1.0% by mass.

  Specific examples of rust inhibitors include amino acid derivatives, partial esters of polyhydric alcohols; esters such as lanolin fatty acid esters, alkyl succinic acid esters, and alkenyl succinic acid esters; sarcosine; polyhydric alcohol moieties such as sorbitan fatty acid esters. Esters; metal soaps such as fatty acid metal salts, lanolin fatty acid metal salts, and oxidized wax metal salts; sulfonates such as calcium sulfonate and barium sulfonate; oxidized wax; amines; phosphoric acid; It can be illustrated. Of these, amino acid derivatives are preferred because of their high rust prevention effect.

As said amino acid derivative, the compound shown by following General formula (8) is mentioned.

In the formula (8), A is a group represented by the formula (9) or the formula (10), and B is a residue of an alkyl group having 1 to 12 carbon atoms or a monovalent carboxylic acid ester represented by the formula (11). R ²⁴ is an alkyl group having 4 to 12 carbon atoms, and R ²⁵ is an alkyl group having 1 to 10 carbon atoms.
^{R 27 O-CO-R 26} - (9)
R ²⁹ O—CO—R ²⁸ —CO— (10)
-C-CO-O-R ³⁰ (11)
(In the formulas (9) to (11), R ²⁶ is an alkylene group having 1 to 12 carbon atoms, R ²⁸ is an alkylene group having 1 to 10 carbon atoms, and R ²⁷ and R ²⁹ are each a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, R ³⁰ is an alkyl group having 1 to 10 carbon atoms.)

R ²⁴ is an alkyl group having 4 to 12 carbon atoms, preferably an alkyl group having 4 to 10 carbon atoms, and more preferably an alkyl group having 6 to 10 carbon atoms. R ²⁵ and R ³⁰ are each independently an alkyl group having 1 to 10 carbon atoms, preferably an alkyl group having 1 to 8 carbon atoms, and more preferably an alkyl group having 1 to 6 carbon atoms. R ²⁹ is hydrogen or an alkyl group having 1 to 10 carbon atoms, preferably an alkyl group having 1 to 8 carbon atoms, and more preferably an alkyl group having 1 to 6 carbon atoms.

  In the present invention, one or two or more compounds arbitrarily selected from these rust inhibitors can be contained in the hydraulic fluid composition in any amount, but usually the content thereof Is preferably 0.001 to 2.0 mass%, more preferably 0.01 to 1.5 mass%, still more preferably 0.05 to 1 mass%, based on the total amount of the hydraulic fluid composition.

  Specific examples of the metal deactivator include benzotriazole, thiadiazole, and imidazole compounds. In the present invention, one or two or more compounds arbitrarily selected from these metal deactivators can be contained in any amount, but the content is usually determined by hydraulic operation. It is desirable that it is 0.001-1 mass% on the basis of the total amount of the oil composition.

  Specific examples of the viscosity index improver include a copolymer of one or more monomers selected from various methacrylates or a hydrogenated product thereof, an ethylene-α-olefin copolymer (as α-olefin). Can be exemplified by propylene, 1-butene, 1-pentene, etc.) or a hydride thereof, polyisobutylene or a hydrogenated product thereof, a hydride of a styrene-diene copolymer, and a so-called non-dispersed viscosity. An index improver etc. can be illustrated. In the present invention, one or two or more compounds arbitrarily selected from these viscosity index improvers can be contained in any amount, but the content is usually determined by hydraulic fluid. The content is desirably 0.01 to 10% by mass based on the total amount of the composition.

  Specific examples of the pour point depressant include copolymers of one or more monomers selected from various acrylic esters and methacrylic esters or hydrogenated products thereof. In the present invention, one or two or more compounds arbitrarily selected from these pour point depressants can be contained in any amount, but the content thereof is usually hydraulic oil. It is desirable that it is 0.01-5 mass% on the basis of the total amount of the composition.

Specific examples of the antifoaming agent include silicones such as dimethyl silicone and fluorosilicone. In the present invention, one or two or more compounds arbitrarily selected from these antifoaming agents can be contained in any amount, but the content is usually determined by the hydraulic fluid composition. It is desirable that it is 0.001-0.05 mass% on the basis of the total amount of things.
Examples of the demulsifier include polyoxyalkylene glycol, polyoxyalkylene alkyl ether, polyoxyalkylene alkylamide, polyoxyalkylene fatty acid ester and the like.
Specific examples of the stick-slip preventing agent include polyhydric alcohol esters (complete esters and partial esters).
Specific examples of the oily agent include fatty acids, esters, alcohols and the like. Usually, the content is desirably 0.01 to 0.5% by mass based on the total amount of the hydraulic fluid composition.

The flash point of the hydraulic fluid composition of the present invention is 280 ° C. or higher, preferably 300 ° C. or higher, and has excellent flame retardancy. In particular, fatty acid esters and fats and oils have a higher flash point than mineral oil, and the risk of fire is substantially reduced. In addition, since the flash point is 280 ° C. or higher, it becomes a flammable liquid by deviating from the designation of hazardous materials of the fourth petroleum of the Fire Service Act, and handling becomes easy.
Here, the flash point is a value measured in accordance with JIS K 2265 “Crude oil and petroleum products—flash point test method”.

  Hereinafter, the contents of the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these contents.

(Examples 1-4, Comparative Examples 1-4)
As shown in Table 1, a base oil and additives were blended to prepare a hydraulic fluid composition. The base oils and additives used in the examples and comparative examples are as follows.

<Base oil>
Base oil A1: oleic acid ester of trimethylolpropane (kinematic viscosity 47.2 mm ² / s (@ 40 ° C.), viscosity index 190)
Base oil A2: High oleic acid-containing rapeseed oil (kinematic viscosity 35 mm ² / s (@ 40 ° C.), viscosity index 190, ratio of oleic acid to all fatty acids constituting ester, 75 mol%, occupied by all fatty acids constituting ester Unsaturated fatty acid ratio 90 mol%)
Base oil A3: mixed fatty acid ester of pentaerythritol and octylic acid and decanoic acid (kinematic viscosity 34.2 mm ² / s (@ 40 ° C.), viscosity index 130)

<Antioxidant (B)>
B1: Bis (4-dimethylaminophenyl) methane B2: α-naphthylamine B3: 4,4′-methylenebis (2,6-di-tert-butylphenol)

<Abrasion inhibitor (C)>
C1: triphenylthiophosphate C2: 2-ethylhexyl acid phosphate C3: tricresyl phosphate

〔ここで、Ｒ^１はオクチル基、Ｒ^２はブチル基、Ｒ^３はブチレン基を示す。〕
Ｄ２：ソルビタンモノオレエート
Ｄ３：アルケニルコハク酸部分エステル <Rust preventive (D)>
D1: Amino acid derivative (compound represented by the following formula)

[Wherein R ¹ represents an octyl group, R ² represents a butyl group, and R ³ represents a butylene group. ]
D2: Sorbitan monooleate D3: Alkenyl succinic acid partial ester

<Other additives (E)>
E1: N methylbenzotriazole E2: Polymethacrylate (molecular weight 50,000)

  The prepared hydraulic fluid composition was subjected to flash point, dry toast test, four-ball test, FZG gear test, V104C vane pump test, rust test and biodegradability test. The results are shown in Table 1.

[Flash point]
JIS K 2265 “crude oil and petroleum products—flash point test method”.

[Dry toast test]
In accordance with the “Oxidation Stability Method” defined in JIS K 2514, 300 ml of sample oil is collected in a specified container, an iron and copper coiled catalyst is added, and an oxidation stability test is performed in a 95 ° C. water bath. Do not use water. During the test, sample oil was sampled little by little, and the acid value increase and the amount of sludge (filtered a certain amount of sample oil through a filter and measured from the residue weight) were measured.

[Four ball test]
It complies with lubricant extreme pressure performance measurement for a standard test method prescribed in ASTMD2783-88 (Four-Ball Method) [Standard Test Method for Measurement of Extreme-Pressure Properties of Lubricating Fluids (Four- Ball Method)], rotational speed 1200Min ^{- 1. The} test is carried out under the conditions of a load of 294 N, an oil temperature of 75 ° C., and a test time of 1 hour, and the average value of the wear scar diameter (mm) of the three fixed balls is measured.

[FZG gear test]
Gear test as defined in ASTM D5182. The test is started at 1500 rpm (rotation number 1500 rpm / min ⁻¹ ), test start oil temperature 90 ° C., the gear is loaded with the weight specified in each stage, and is operated for 15 minutes. The oil seizure resistance is evaluated on a stage where the gears burn. Report the stage of the load where the gear is burned as a failure.

[Vane pump test (V104C test)]
A vane pump test defined in ASTM D 2882 was conducted, the weight of the vane and the ring before and after the test was measured, and the amount of wear was measured. The test time was 100 hours.

[Rust prevention test]
Rust prevention test using general steel materials for polished steel bars specified in JISK2510. There are two types of test methods, distilled water and artificial seawater, depending on the water used, but this time the test was conducted with more severe artificial seawater. The test time is 24 hours and the test oil temperature wave is 60 ° C.

[Biodegradability test]
A biodegradability test was conducted by the OECD 301C method defined in the biodegradable hydraulic oil standard ISO15380. The biodegradability of the sample oil is evaluated using activated sludge collected from 10 or more sewage treatment plants. There are various test methods depending on the evaluation method. In this method, the decomposition rate is measured by the BOD (biochemical oxygen demand) of the sample oil. It is evaluated that there is biodegradability when it degrades by 60% in a 28-day test.

Claims (3)

(A) To at least one base oil selected from the group consisting of synthetic esters and fats and oils,
(B) 0.01 to 5.0% by mass of the bis (4-dialkylaminophenyl) methane antioxidant represented by the formula (1) based on the total amount of the composition, and
(C) 0.001 to 5% by mass of at least one antiwear agent selected from sulfur-containing phosphate ester, acidic phosphate ester, acidic phosphate amine salt and phosphite ester based on the total amount of the composition,
And a flame-retardant hydraulic fluid composition characterized by having a flash point of 280 ° C. or higher.

[R ¹ , R ² , R ³ and R ⁴ may be the same as or different from each other, and are each an alkyl group having 1 to 6 carbon atoms. ]   The flame retardant according to claim 1, wherein the fatty acid constituting the synthetic ester is a fatty acid obtained from an animal or plant raw material, and the ratio of the unsaturated fatty acid to the fatty acid constituting the synthetic ester is 30 mol% or more. Hydraulic fluid composition.   The flame retardant hydraulic fluid composition according to claim 1 or 2, further comprising 0.01 to 5 mass% of a phenolic antioxidant as an antioxidant based on the total amount of the composition.