JP2019199575A - Turbine oil composition - Google Patents

Abstract

To provide the turbine oil composition excellent in biodegradability, thermal oxidation stability, and hydrolysis stability.SOLUTION: The turbine oil composition comprises: a base oil portion containing polyol ester, and 0.05% to 0.15 mass% of a carbodiimide compound as a hydrolysis inhibitor, wherein the polyol ester consists of an alcohol residue having neopentyl structure and a saturated fatty acid residue of a mixture of a linear saturated fatty acid having 7 to 11 carbon atoms and a branched saturated chain fatty acid having 16 to 20 carbon atoms, and has a kinematic viscosity at 40°C of 32 mm/s to 68 mm/s.SELECTED DRAWING: None

Description

  The present invention relates to a turbine oil composition.

In recent years, the importance of environmental conservation has increased, and lubricants used in equipment and facilities used outdoors or in the natural environment can be discharged into the natural environment during or after use. The number of cases where is required is increasing.
In recent years, turbine oil for generators used in facilities in the natural environment, such as hydroelectric power plants, geothermal power plants, and wind power plants near rivers or lakes, have been Degradability has been demanded.

In such a case, there is an Eco Mark certification standard established by the Japan Environment Association as an index indicating the biodegradability of lubricating oil. In the case of lubricating oil, Eco Mark product type No. Products that are classified into 110 and have acquired the Eco Mark in accordance with the certification standard “Biodegradable Lubricating Oil Version 2.6” are generally recognized as biodegradable lubricating oils and are widely used. According to this “Biodegradable Lubricating Oil Version 2.6”, in order to obtain the Eco Mark, the biodegradability must be 60% or more within 28 days by one of the following test methods. Is one of the requirements.
That is, in any one test method among OECD 301B, 301C, 301F, or ASTM D5864, D6731, the degree of biodegradation within 28 days is required to be 60% or more.

  In general, as a method for improving the biodegradability of a lubricating oil, there are many cases in which a base oil having a high biodegradability is used as the main component of the base oil, and a polyol ester base oil is used as a turbine oil for hydroelectric power generation. A technique for improving biodegradability is known (for example, see Patent Document 1).

  Turbine oil is replaced in many cases in accordance with regular repairs of power generation facilities that have been operating for a long period of time, so the oil renewal period may be as long as 10 years. Naturally, basic performances such as thermal oxidation stability, sludge prevention and hydrolysis stability, and corrosion resistance to metal materials used for turbine bearings are also emphasized.

  Therefore, when improving the biodegradability of turbine oil, it is necessary to pay attention to ensuring these basic performances.

Examples of turbine oil compositions having excellent biodegradability, low pour point, and excellent thermal oxidation stability include (A) polyhydric alcohol residues, linear saturated fatty acid residues, and linear saturated polycarboxylic acids. And a complex ester having a kinematic viscosity at 40 ° C. of ²⁰ to 100 mm ² / s and a pour point of −40 ° C. or less, and (B) an antioxidant. Moreover, the turbine oil composition characterized by the content rate of (A) in a base oil component being 60 mass% or more is disclosed (for example, refer patent document 2).
In addition, the base oil is (A) a trimethylolpropane residue, a C8 linear saturated fatty acid, a C10 linear saturated fatty acid, a C12 linear saturated fatty acid, a C14 linear saturated fatty acid, and a C16 linear saturated fatty acid. And a mixture of two or more of them, a linear saturated fatty acid residue and an adipic acid residue, a kinematic viscosity at 40 ° C. of 32 to 68 mm ² / s, and a pour point of −40 ° C. or less A turbine oil composition for a hydroelectric power generation facility of a hydroelectric power plant that is an ester and contains (B) an antioxidant is disclosed (for example, see Patent Document 3).

JP 2008-115301 A JP 2014-055284 A Japanese Patent No. 6114961

When an ester base oil is used to improve biodegradability in turbine oil, it may be difficult to ensure these basic performances.
In order to improve biodegradability as in Patent Documents 1 to 3, the mainstream is to use a fatty acid ester as the base oil of the lubricating oil. However, when water is mixed in the turbine oil, hydrolysis is performed. As a result, there is a concern that the acid value of the oil will increase and the life of the turbine oil will decrease, and further improvements are required.
Accordingly, an object of the present invention is to provide a turbine oil composition that is excellent in biodegradability, thermal oxidation stability, and hydrolysis stability in order to solve the above problems.

  As a result of intensive studies, the present inventors have found that the above-mentioned problems can be solved by including a specific polyol ester as the base oil, and have completed the present invention.

That is, the following embodiments are included in the means for solving the above problems.
<1> An alcohol residue having a neopentyl structure and a saturated fatty acid residue of a mixture of a linear saturated fatty acid having 7 to 11 carbon atoms and a branched saturated fatty acid having 16 to 20 carbon atoms, and at 40 ° C. kinematic viscosity comprises a polyol ester is 32mm ² / s~68mm ² / s, containing a base oil, and a carbodiimide compound 0.05% 0.15 wt% as a hydrolysis inhibitor, a turbine oil Composition.
<2> The turbine oil composition according to <1>, further comprising at least one selected from the group consisting of an antioxidant, a demulsifier, a rust inhibitor, and a corrosion inhibitor.
<3> The turbine oil composition according to <1> or <2>, wherein the degree of biodegradation according to the OECD301B method or the OECD301C method is 60% or more, and <1> to <3> for hydroelectric power generation equipment. The turbine oil composition according to any one of the above.

  According to the present invention, a turbine oil composition excellent in biodegradability, thermal oxidation stability, and hydrolysis stability can be provided.

Hereinafter, embodiments for carrying out the present invention will be described in detail.
In addition, in this specification, "-" showing a numerical range represents the range containing the numerical value each described as the upper limit and the minimum. In addition, when only the upper limit value is described in the numerical range represented by “to”, it means that the lower limit value is also the same unit.
In the numerical ranges described stepwise in this specification, the upper limit value or the lower limit value described in a numerical range may be replaced with the upper limit value or the lower limit value of another numerical range described.
In the present specification, the content rate or content of each component in the composition is such that when there are a plurality of substances corresponding to each component in the composition, the plurality of kinds present in the composition unless otherwise specified. It means the total content or content of substances.
In the present specification, a combination of preferred embodiments is a more preferred embodiment.

<Turbine oil composition>
The turbine oil composition of the present invention comprises an alcohol residue having a neopentyl structure and a saturated fatty acid residue of a mixture of a straight chain saturated fatty acid having 7 to 11 carbon atoms and a branched saturated fatty acid having 16 to 20 carbon atoms. and a base oil containing a polyol ester kinematic viscosity of 32mm ² / s~68mm ² / s at 40 ° C., and a carbodiimide compound 0.05% 0.15 wt% as a hydrolysis inhibitor, Containing.
The turbine oil composition of the present invention is excellent in biodegradability, thermal oxidation stability and hydrolysis stability by having the above-described configuration. The reason for this is not clear, or is presumed as follows.

Viscosity grade common turbine oils, VG46 (40 ° C. kinematic viscosity 41.4mm ² /s~50.6mm ² / s) is. In order to prepare a turbine oil having a high kinematic viscosity grade of about VG46 using a polyol ester base oil, it is necessary to increase the molecular weight of the ester. In this case, in order to ensure a low pour point while ensuring a high kinematic viscosity (that is, a large molecular weight), it is necessary to use a linear unsaturated fatty acid having a large molecular weight or a branched saturated fatty acid having a large molecular weight. . However, when linear unsaturated fatty acids are used, the biodegradability is good but the thermal oxidation stability is low. On the other hand, when branched saturated fatty acids are used, the thermal oxidation stability is low. Although there is a problem that the biodegradability is low, the biodegradability and thermal oxidation stability are in a trade-off relationship.
The turbine oil composition of the present invention is hydrolyzed while using a polyol ester that is a combination of an alcohol having a neopentyl structure and a linear saturated fatty acid having 7 to 11 carbon atoms and a branched saturated chain fatty acid having 16 to 20 carbon atoms. By adding a specific amount of a carbodiimide compound as an inhibitor, the biodegradability, thermal oxidation stability and hydrolysis stability are all excellent. In addition, the turbine oil composition of the present invention can ensure a high kinematic viscosity of about VG46 despite the fact that it contains a polyol ester as the base oil.
Hereinafter, each component which comprises the turbine oil composition of this invention is demonstrated.

<Base oil content>
The turbine oil composition of the present invention has, as a base oil, a saturated fatty acid residue of a mixture of an alcohol residue having a neopentyl structure, a linear saturated fatty acid having 7 to 11 carbon atoms and a branched saturated fatty acid having 16 to 20 carbon atoms. And a polyol ester (hereinafter also referred to as “specific polyol ester”).
In addition, in this specification, carbon number of a linear saturated fatty acid and a branched saturated fatty acid means the total carbon number including the carbon atom which forms the ester bond.

The specific polyol ester, which is the base oil component of the turbine oil composition of the present invention, is an ester produced by a reaction between an alcohol and a carboxylic acid or carboxylic acid derivative. That is, the specific polyol ester is an alcohol residue having a neopentyl structure in which an alcohol residue is a polyhydric alcohol residue, and the acid residue is composed of an alcohol residue derived from an alcohol and an acid residue derived from a carboxylic acid. A straight chain saturated fatty acid residue and a branched chain saturated fatty acid residue.
That is, the specific polyol ester is an ester having an alcohol residue having a neopentyl structure as an alcohol residue and having both a linear saturated fatty acid residue and a branched saturated fatty acid residue as an acid residue. .

By including an alcohol residue having a neopentyl structure as the alcohol residue, the specific polyol ester can easily obtain an appropriate viscosity and a low pour point as a base oil, and has biodegradability and thermal oxidation stability. Easy to balance.
In addition, the alcohol residue having a neopentyl structure is a hindered alcohol residue having a structure in which there is no hydrogen at the β-position of the ester group, so that thermal decomposition of the specific polyol ester hardly occurs.

In the specific polyol ester, the linear saturated fatty acid residue has 7 to 11 carbon atoms.
When the linear saturated fatty acid residue has 7 to 11 carbon atoms, the molecular weight of the specific polyol ester is not too small, the pour point and viscosity desired as turbine oil are obtained, and biodegradability is also obtained. Moreover, since the said linear fatty acid residue is a saturated fatty acid residue, it is excellent in thermal oxidation stability.

In the specific polyol ester, the valence of the linear saturated fatty acid residue is preferably 1.
Further, in this specification, the valence of the linear saturated fatty acid residue and the branched saturated fatty acid residue refers to the number of ester bonds formed by the linear saturated fatty acid residue or the branched saturated fatty acid residue. .

In the synthesis of the specific polyol ester, a carboxylic acid or a carboxylic acid derivative that becomes a linear saturated fatty acid residue having 7 to 11 carbon atoms by reaction with an alcohol having a neopentyl structure includes an acid residue by reaction with an alcohol having a neopentyl structure. Examples thereof include carboxylic acids or carboxylic acid derivatives such as straight chain saturated fatty acids, straight chain saturated fatty acid chlorides or straight chain saturated fatty acid esters having 7 to 11 carbon atoms.
The carboxylic acid or carboxylic acid derivative that becomes the linear saturated fatty acid residue may be used singly or in combination of two or more.

In the specific polyol ester, the branched saturated fatty acid residue has 16 to 20 carbon atoms. If the branched chain saturated fatty acid residue has 16 to 20 carbon atoms, the specific polyol ester has a large molecular weight, so that it is easy to obtain the pour point and viscosity desired as a turbine oil. Excellent prevention. Moreover, since the said branched chain fatty acid residue is a saturated fatty acid residue, it is excellent in thermal oxidation stability.
In the specific polyol ester, the valence of the branched chain saturated fatty acid residue is preferably 1.

Specific polyol ester, as long as the kinematic viscosity at 40 ° C. is a 32mm ² / s~68mm ² / s, the alcohol residue having a neopentyl structure, straight chain fatty acid residues and the number of carbon atoms of 7 to 11 carbon atoms. 16 The ratio of the 20 branched chain fatty acid residues and the molecular weight of the specific polyol ester are not particularly limited.
Moreover, kinematic viscosity at 40 ° C. for a specific polyol ^ester, if 32mm ² / s~68mm 2 / s, the kind of reaction conditions and processes of preparation of particular polyol ester is not particularly limited.

  In the specific polyol ester, the ratio of linear saturated fatty acid to branched saturated fatty acid (linear saturated fatty acid: branched saturated fatty acid) is from the viewpoint of appropriate kinematic viscosity, biodegradability, thermal oxidation stability and hydrolysis stability. 85-35: 15-35, more preferably 75-45: 25-55, and still more preferably 65-55: 35-45.

<Kinematic viscosity at 40 ° C.>
Kinematic viscosity at 40 ° C. in particular polyol ester ^is 32mm ² / s~68mm 2 / s. When the kinematic viscosity at 40 ° C. is in the above range, a sufficient oil film can be retained, and flow resistance and stirring are suppressed by suppressing an increase in viscosity when a turbine oil is prepared by blending additives. Since the resistance is reduced, power loss and temperature rise of the turbine bearing metal can be suppressed.
From the above viewpoint, the kinematic viscosity at 40 ° C. for a specific polyol ester is ^preferably 32mm ² / s~68mm 2 / s, more preferably from 39mm ² / s~57mm ² / s.
The kinematic viscosity at 40 ° C. can be determined according to JIS K 2283 (2000) “Kinematic Viscosity Test Method”.

<Kinematic viscosity at 100 ° C.>
Kinematic viscosity at 100 ° C. for a specific polyol ester ^is preferably 5mm ² / s~10mm 2 / s.
From the viewpoint of lubricity, kinematic viscosity at 100 ° C. for a specific polyol ester is ^preferably 6mm ² / s~9mm 2 / s, more preferably at 6.5mm ² /s~8.5mm ² / s .

The pour point of the specific polyol ester is preferably −40 ° C. or lower, more preferably −45 ° C. or lower.
When the pour point of the specific polyol ester is −40 ° C. or less, a sufficient oil film can be retained, and the increase in viscosity when the turbine oil is prepared by blending additives is Since the resistance and the stirring resistance are reduced, power loss and temperature increase of the turbine bearing metal can be suppressed.

Iodine value of a specific polyol ester is preferably _GI 2/100 g or less, and more preferably not more than _{1 gI} 2/100 g.
When the iodine value of the specific polyol ester is ₂ gI 2/100 g or less, the thermal oxidation stability is more excellent.

  The acid value of the specific polyol ester is preferably 5 mgKOH / g or less, more preferably 3 mgKOH / g or less, still more preferably 1 mgKOH / g or less. When the acid value of the specific polyol ester is in the above range, the anti-emulsifying property is increased, and corrosion of a metal material such as a bearing can be suppressed.

The turbine oil composition of the present invention may contain a base oil other than the specific polyol ester (hereinafter also referred to as “other base oil”) as a base oil component.
Other base oils are not particularly limited as long as they do not impair the biodegradability and thermal oxidation stability of the turbine oil composition.
Other base oils include, for example, monoesters, diesters and polyol esters, polyglycols and the like that do not have a linear saturated fatty acid residue having 7 to 11 carbon atoms and a branched saturated fatty acid residue having 16 to 20 carbon atoms. Can be mentioned.
Examples of the polyglycol include polyethylene oxide.

In the turbine oil of the present invention, the content ratio of the specific polyol ester in the base oil ((specific polyol ester content / total base oil content) × 100) is 60% by mass or more, preferably 70% by mass or more. Preferably it is 80 mass% or more, More preferably, it is 90% mass% or more, Most preferably, it is 95 mass% or more.
In addition, it is preferable that the content of other base oils is smaller in terms of favorable biodegradability and various performances as turbine oil, and the content ratio of the specific polyol ester in the base oil is 100% by mass. More preferably.

<Hydrolysis inhibitor>
The turbine oil composition of the present invention contains a carbodiimide compound as a hydrolysis inhibitor.
There is no restriction | limiting in particular as a carbodiimide compound, If it is a compound which contains a carbodiimide group in 1 molecule, there will be no restriction | limiting in particular, For example, a monocarbodiimide compound, a polycarbodiimide compound, a cyclic carbodiimide compound etc. are mentioned.
Among these, as the carbodiimide compound, a monocarbodiimide compound is preferable.
Examples of the monocarbodiimide compound include dicyclohexylcarbodiimide, bis-2,6-diisopropylphenylcarbodiimide, and the like.
From the viewpoint of superior hydrolysis resistance, the carbodiimide compound is preferably bis-2,6-diisopropylphenylcarbodiimide.

The content of the carbodiimide compound is 0.05% by mass to 0.15% by mass with respect to the total mass of the turbine oil composition. When the content of the carbodiimide compound is within the above range, the hydrolysis preventing effect can be exhibited without significantly reducing biodegradability.
From the above viewpoint, the content of the carbodiimide compound is 0.08% by mass to 0.00% with respect to the total mass of the turbine oil composition. It is preferably 12% by mass.

<Additives>
The turbine oil composition of the present invention preferably further contains at least one selected from the group consisting of antioxidants, demulsifiers, rust inhibitors and corrosion inhibitors.

(Antioxidant)
The antioxidant is preferably an ashless antioxidant because the antioxidant itself is less likely to sludge.
Ashless type antioxidants are chain terminators that absorb radicals, and examples thereof include alkylated aromatic antioxidants such as alkylbenzene and alkylnaphthalene, phenolic antioxidants, and amine-based antioxidants.
Among these, from the viewpoint of thermal oxidation stability, the antioxidant is preferably a phenol-based antioxidant and an amine-based antioxidant.
When the antioxidant is a phenolic antioxidant or an amine antioxidant, either a phenolic antioxidant or an amine antioxidant may be used, or a combination of these may be used.

  Examples of phenolic antioxidants include 2,6-di-t-butylphenol, 2,6-di-t-butyl-4-methylphenol, 2,6-di-t-butyl-4-ethylphenol, Monocyclic phenols such as 2,4,6-tri-methylphenol, 2,6-di-methyl-4-ethylphenol, 2,4-di-methyl-6-tert-butyl-phenol; -Bis (2,6-di-t-butylphenol), 4,4'-methylenebis (2,6-di-t-butylphenol), 4,4'-ethylenebis (2,6-di-t-butylphenol) Bisphenols such as 4,4′-butylenebis (2,6-di-t-butylphenol), 6,6′-methylenebis (2-di-t-butyl-4-methylphenol); (2,6-di-t- Butyl-phenol), sulfur-containing phenols such as 4,4′thiobis- (2-methyl-6-tert-butyl-phenol); ester group-containing phenols represented by the following general formula (1); Sulfur and ester group-containing phenols represented by (2) or the following general formula (3) are exemplified.

In General Formula (1), R ¹ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, R ² is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and R ³ is an alkyl group having 1 to 18 carbon atoms. An alkylene group, R ⁴ is an alkyl group having 1 to 20 carbon atoms, and n is an integer of 1 to 4;

In General Formula (2), R ⁵ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, R ⁶ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and R ⁷ is an alkyl group having 1 to 18 carbon atoms. an alkylene group, ^{a 1} is a sulfide group of the sulfur atom or a C 1 to 20, n is an integer of 1 to 4.

In General Formula (3), R ⁸ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, R ⁹ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and R ¹⁰ is an alkyl group having 1 to 20 carbon atoms. an alkyl group, ^{a 2} is a sulfide group of the sulfur atom or a C 1 to 20, n is an integer of 1 to 4.

Of these, the phenolic antioxidant is preferably a monocyclic phenolic antioxidant, a bisphenolic antioxidant, or an ester group-containing phenolic antioxidant.
When it is an ester group-containing phenolic antioxidant, in general formula (1), R ¹ and R ² are preferably an alkyl group having 1 to 4 carbon atoms, more preferably an isoalkyl group, and still more preferably a t-butyl group. In general formula (1), those in which both R ¹ and R ² are other than hydrogen atoms are easily stabilized when a radical is captured. R ³ is preferably an alkylene group having 1 to 18 carbon atoms. If the carbon number of R ³ is 18 or less, the solubility is excellent. R ⁴ is preferably an alkyl group having 1 to 18 carbon atoms. If the oxygen number of R ⁴ is 18 or less, the solubility is excellent. N is preferably 1 or 2. Oil solubility becomes high as n is 4 or less.
One type of phenolic antioxidant may be used alone, or two or more types may be used in combination.

  The content of the phenolic antioxidant in the turbine oil composition of the present invention is preferably 0.01% by mass to 3% by mass, more preferably 0.1% by mass to the total mass of the turbine oil composition. 2% by mass. When the content of the phenolic antioxidant in the turbine oil composition is within the above range, the generation of sludge can be suppressed, and the antioxidant effect can be exhibited while maintaining biodegradability.

  Specific examples of amine-based antioxidants include naphthylamine compounds such as phenyl-α-naphthylamine; diphenylamine compounds such as alkylated diphenylamine represented by the following general formula (4); N, N-di-t Phenylenediamine compounds such as -butyl-p-phenylenediamine; heteroatom-containing aromatic amine compounds such as phenothiazine, etc., which are hindered amine compounds in which the amino group is shielded by an aromatic ring, t-butyl group, is there.

In General Formula (4), R ¹¹ is a hydrogen atom or an alkyl group having 1 to 24 carbon atoms, and R ¹² is a hydrogen atom or an alkyl group having 1 to 24 carbon atoms.

Among these, as an amine antioxidant, a naphthylamine compound, a diphenylamine compound or a phenylenediamine compound is preferable, and a diphenylamine compound is more preferable.
When the amine-based antioxidant is a diphenylamine compound, in the general formula (4), R ¹¹ and R ¹² are each preferably an alkyl group having 1 to 18 carbon atoms, and both have 1 to 12 carbon atoms. The alkyl group is more preferably. When the carbon number of R ¹¹ or R ¹² is 24 or less, the fluidity is increased. R ¹¹ and R ¹² more preferably include an alkyl group having a branched chain.
One type of amine-based antioxidant may be used alone, or two or more types may be used in combination.

The content of the amine-based antioxidant is preferably 0.01% by mass to 3% by mass and more preferably 0.1% by mass to 2% by mass with respect to the total mass of the turbine oil composition.
When the content of the amine-based antioxidant in the turbine oil composition of the present invention is within the above range, the generation of sludge can be suppressed, and the antioxidant effect can be exhibited while maintaining biodegradability. .

  When the phenolic antioxidant and the amine antioxidant are used in combination, the content ratio of the phenolic antioxidant and the amine antioxidant is preferably 10: 1 to 1:10 in terms of mass ratio, and 5: 1. ˜1: 5 is more preferable, and 3: 1 to 1: 3 is still more preferable.

  When the turbine oil composition of the present invention contains an antioxidant, the total content of the antioxidant in the turbine oil composition is preferably 0.01% by mass to 3% with respect to the total mass of the turbine oil composition. % By mass, more preferably 0.1% by mass to 2% by mass.

(Demulsifier)
The main component of the demulsifier is a surfactant, and the demulsifier is preferably a nonionic surfactant, more preferably a polyalkylene glycol.
Examples of the polyalkylene glycol include a homopolymer obtained by polymerizing ethylene glycol, propylene glycol, or butylene glycol as monomers, or a copolymer obtained by polymerizing these in combination. The homopolymer and the copolymer may be used alone or in combination of two or more.
The nonionic surfactant is preferably a copolymer polymerized by combining ethylene glycol, propylene glycol or butylene glycol as monomers, and ethylene oxide-propylene oxide polymerized by combining ethylene glycol and propylene glycol. More preferably, it is a copolymer.

  As a weight average molecular weight of a demulsifier, 100-20,000 are preferable and 1,000-15,000 are more preferable. When the main component is an ethylene oxide-propylene oxide copolymer, the molar ratio of ethylene oxide: propylene oxide is preferably 20: 1 to 1:10, and more preferably 10: 1 to 1: 5.

The content of the demulsifier is preferably 0.001% by mass to 0.2% by mass and more preferably 0.005% by mass to 0.1% by mass with respect to the total mass of the turbine oil composition.
When the content of the demulsifier is within the above range, the demulsifying effect is easily obtained.

(Anti-rust agent)
It is preferable that the rust inhibitor is an oil-soluble rust inhibitor contained for the purpose of preventing rust at a location where an iron-based material is used.
As an oil-soluble rust inhibitor having a structure having an alkyl group responsible for oil solubility and a functional group adsorbed on a metal surface, for example, metal soaps such as sulfonate metal salts and metal salts of naphthenic acid, alkyl succinic acid derivatives, Surfactants such as alkenyl succinic acid derivatives, lanolin compounds, sorbitan monooleate and pentaerythritol monooleate, alkylated amines such as wax, oxidized wax, petrolatum, N-oleyl sarcosine, rosinamine, dodecylamine and octadecylamine Examples thereof include compounds, fatty acids such as oleic acid and stearic acid, and phosphorus compounds such as phosphite.

Among these, as the rust inhibitor, surfactants other than alkyl succinic acid derivatives, alkenyl succinic acid derivatives, demulsifiers, or alkylated amine compounds are preferable, and alkyl succinic acid derivatives or alkenyl succinic acid derivatives are more preferable. Preferably, alkenyl succinic acid half ester is more preferable.
When the rust inhibitor is alkenyl succinic acid half ester, the acid value is preferably 100 mgKOH / g or more.
These rust inhibitors may be used alone or in combination of two or more.

When the turbine oil composition of the present invention contains a rust inhibitor, the content of the rust inhibitor is preferably 0.001% by mass to 1% by mass, more preferably, relative to the total mass of the turbine oil composition. It is 0.01 mass%-0.5 mass%.
When the content of the rust inhibitor is within the above range, it is possible to suppress the generation of sludge and exhibit the rust inhibitory effect while maintaining biodegradability.

(Corrosion inhibitor)
The corrosion inhibitor is mainly a non-ferrous metal material and is added for the purpose of preventing corrosion at a place where a copper-based or lead-based material is used, and is also called a metal deactivator. Moreover, since the corrosion inhibitor suppresses the catalytic action of the metal, it also functions indirectly as an antioxidant.

The corrosion inhibitor is not particularly limited as long as it is a compound that exhibits a corrosion prevention effect by forming a film on a metal surface. For example, benzotriazole and its derivatives, indazole and its derivatives, benzimidazole and its derivatives , Indole and derivatives thereof, thiadiazole and derivatives thereof, and the like.
Among these, as the corrosion inhibitor, benzotriazole and its derivatives, and thiadiazole and its derivatives are preferable. Further, among the corrosion inhibitors, those having low oil solubility such as benzotriazole may be used as a mixture dissolved with a fatty acid, an amine compound, mineral oil or the like.
One type of corrosion inhibitor may be used alone, or two or more types may be used in combination.

When the turbine oil composition of the present invention contains a corrosion inhibitor, the content of the corrosion inhibitor is preferably 0.001% by mass to 0.5% by mass with respect to the total mass of the turbine oil composition. Preferably it is 0.01 mass%-0.2 mass%.
When the content of the corrosion inhibitor is within the above range, generation of sludge can be suppressed, and the corrosion prevention effect can be exhibited while maintaining biodegradability.

When the turbine oil composition of the present invention contains an antioxidant, a demulsifier, a rust inhibitor and a corrosion inhibitor, the total of the antioxidant, demulsifier, rust inhibitor and corrosion inhibitor in the turbine oil composition The content is preferably 0.1% by mass to 5% by mass and more preferably 0.5% by mass to 3% by mass with respect to the total mass of the turbine oil composition.
When the total content of the antioxidant, demulsifier, rust inhibitor and corrosion inhibitor in the turbine oil composition is within the above range, thermal oxidation is suppressed while suppressing sludge generation and maintaining biodegradability. Performances as turbine oil such as stability and corrosion resistance are easily obtained.

The turbine oil composition of the present invention contains an appropriate amount of other components as necessary within the range not impairing the effects of the present invention, in addition to the above-mentioned antioxidant, demulsifier, rust inhibitor and corrosion inhibitor component. be able to.
Other components include, for example, kerosene fraction, solvent refined mineral oil, hydrorefined mineral oil, hydrocracked mineral oil and other mineral oil base oils, poly-α-olefins and olefin copolymers, olefin base oils such as polybutene, Other base oils such as glycol base oils such as polyalkylene glycol and phenyl ether base oils may be mentioned.

  Further, as other components, for example, components used in ordinary lubricating oil compositions, detergents, dispersants, pour point depressants, viscosity index improvers, antifoaming agents, antiwear agents, friction modifiers, Other additives such as an extreme pressure agent, an oily agent, and a surfactant other than the above demulsifiers may be mentioned.

Examples of the detergent include sulfonate, phenate, salicylate, and the like.
Examples of the dispersant include alkenyl succinimides and boron compound derivatives of alkenyl succinimides.
Examples of the pour point depressant include polymethacrylate.
Examples of the viscosity index improver include polymethacrylate and olefin copolymer.

(Defoamer)
There is no restriction | limiting in particular as an antifoamer, For example, ester type antifoamers, such as silicone type antifoamers, such as a dimethyl silicone and a fluorine-modified silicone, polyacrylate, etc. are mentioned.
Among these, from the viewpoint of antifoaming properties, the antifoaming agent is preferably a silicone-based antifoaming agent, and more preferably dimethylsilicone.
As the antifoaming agent, it is ^preferable, 1,000mm ² / ^s~50,000mm 2 / s and more preferably a kinematic viscosity at 25 ° C. is 500mm ² / s~100,000mm ² / s.
When the turbine oil composition contains an antifoaming agent, the content of the antifoaming agent is preferably 1 ppm to 50 ppm, more preferably 2 ppm to 30 ppm, based on the total mass of the turbine oil composition. When the content of the antifoaming agent is within the above range, the defoaming effect can be obtained without causing aggregation and sedimentation.

Examples of the antiwear agent and extreme pressure agent include zinc dithiophosphate compounds (ZnDTP) and phosphate esters.
Examples of the friction modifier include fatty acids, acidic phosphate esters and their amine salts, organic molybdenum compounds, polyhydric alcohol half esters, amide compounds, and the like.
Examples of the surfactant include anionic surfactants such as Na alkylbenzene sulfonate, nonionic surfactants such as polyoxyethylene alkyl ether and sorbitan fatty acid ester, cationic surfactants, and amphoteric surfactants.

  When the turbine oil composition of the present invention contains other additives, the total content combined with the antioxidant, demulsifier, rust inhibitor and corrosion inhibitor is from the viewpoint of ensuring biodegradability, It is preferable that it is less than 10 mass%.

<Properties of turbine oil composition>
Kinematic viscosity at 40 ° C. of the turbine oil compositions of the present invention is preferably 20mm ² / s~100mm ² / s, more preferably 32mm ² / s~68mm ² / s, more preferably 41.4 mm ² / s to 50.6 mm ² / s.
The turbine oil composition of fatty acid ^esters, although 40 ° C. kinematic viscosity of 41.4mm ² /s~50.6mm 2 / s is a typical kinematic viscosity, fatty acid ester in the range of the kinematic viscosity turbine When trying to prepare an oil composition, as described above, with conventional polyol ester turbine oils, it was difficult to make all of biodegradability, thermal oxidation stability, and hydrolysis stability excellent. According to the present invention, this can be easily achieved.

(Biodegradable)
The turbine oil composition of the present invention preferably has a biodegradation degree of 60% or more according to the OECD 301B method or the OECD 301C method.
It can be said that higher biodegradability is exhibited when the degree of biodegradation of the turbine oil composition is 60% or more.

Since the turbine oil composition of the present invention is excellent in thermal oxidation stability, hydrolyzability and biodegradability, it may be used, for example, as a turbine oil composition for hydroelectric power generation facilities in hydroelectric power plants.
Further, the turbine oil composition of the present invention may be applied to sluice equipment.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to the following examples.

Table 1 shows the raw materials and physical properties of each ester base oil used in the turbine oils of Examples and Comparative Examples.
In addition, each property test was implemented based on the following test methods.
-Kinematic viscosity: JIS K 2283 (2000) "Kinematic viscosity test method"
Viscosity index: JIS K 2283 (2000) “Viscosity index calculation method”
Flash point: JIS K 2265-4 (2007) "Flash point test method (Cleveland open method)"
-Pour point: JIS K 2269 (1987) "Pour point test method"
Acid value: JIS K 2501 (2003) “Neutralization number test method”
・ Iodine value: JIS K 0070 (1992) “Testing methods for acid value, saponification value, ester value, iodine value, hydroxyl value and unsaponified product of chemical products”

A turbine oil composition was prepared by blending the ester base oil shown in Table 1 and the additives shown below in the proportions shown in Table 2 or Table 3.
<Additives>
Amine-based antioxidant: alkylated diphenylamine, a compound in which R ¹¹ and R ¹² in the general formula (4) are a mixture of 4 and 8 carbon atoms.
Phenolic antioxidant: isooctyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, R ¹ and R ² in the general formula (1) are both t-butyl groups, R ³ is an ethylene group, R ⁴ is an isooctyl group, and n is 1.
Demulsifier: A copolymer of ethylene oxide-propylene oxide as the main component. The weight average molecular weight is 5000 to 8000.
Rust inhibitor: alkenyl succinic acid half ester, acid value: 175 mg KOH / g
・ Corrosion inhibitor: benzotriazole derivative ・ Antifoaming agent: Polydimethylsiloxane (other additives)

Tables 2 and 3 show the general properties of the prepared turbine oil composition and the results of a biodegradability test as the composition.
-Evaluation-
<Biodegradability>
The test period was 28 days according to the OECD 301B method or the OECD 301C method specified in the Eco Mark certification standard “Biodegradable Lubricating Oil Version 2.6”. Based on this standard, in a 28-day test, when the degree of biodegradation was 60% or more, it passed, and when it was less than 60%, it was rejected.

<Thermal stability>
Using the turbine oil composition blended in the ratio shown in Table 2 or Table 3 as a sample, 40 ml is taken into a sample bottle and left in a constant temperature bath with a rotating plate at 120 ° C. for a predetermined time (1000 hours). The acid value (mgKOH / g) of the sample was measured, and the change in acid value was determined from the following formula.
Acid value change = acid value after test−acid value before test When the change value of the acid value is 0.1 mgKOH / g or less, it can be determined that the thermal stability is excellent.

<Hydrolysis stability>
ASTM D 2619-95 “Standard Test Method for Hydrodynamic Stability of Hydrodynamic Fluids (Beverage Bottle Method Hydrolysis Method Stabilization Method)” did. The test equipment, temperature, etc. conformed to the test method.
About the amount of sample, the ratio of moisture and the test time, in order to simulate the influence of moisture mixing in long-term use, the sample was stored at 93 ° C. for 480 hours at a moisture ratio of 2000 ppm with respect to 100 g of the sample. The acid value (mgKOH / g) was measured and the change in acid value was determined from the following formula.

Acid value change = acid value of the sample after storage-acid value of the sample before storage

When the change value of the acid value is 0.5 mgKOH / g or less, it can be determined that the hydrolysis stability is excellent.

As shown in Table 2, the turbine oil composition of Example 1 was excellent in all of thermal oxidation stability, hydrolyzability and biodegradability. Further, the biodegradability of the turbine oil composition of Example 1 was 60% or more even in the OECD 301C method.
On the other hand, the base oil consists of an alcohol residue having a neopentyl structure and a saturated fatty acid residue of a mixture of a C7-11 linear saturated fatty acid and a C16-20 branched saturated chain fatty acid. The turbine oil compositions of Comparative Examples 1 to 3 that did not contain a polyol ester did not satisfy all of thermal oxidation stability, hydrolyzability, and biodegradability.

  The turbine oil composition according to the present invention is excellent in thermal oxidation stability, hydrolyzability, and biodegradability, and can be suitably used as turbine oil for hydroelectric power generation facilities.

Claims (4)

It consists of an alcohol residue having a neopentyl structure and a saturated fatty acid residue of a mixture of a linear saturated fatty acid having 7 to 11 carbon atoms and a branched saturated fatty acid having 16 to 20 carbon atoms, and has a kinematic viscosity at 40 ° C. 32mm including ² / ^s~68mm polyol ester is a ² / s, and base oil,
0.05 mass% to 0.15 mass% of a carbodiimide compound as a hydrolysis inhibitor,
A turbine oil composition comprising:   The turbine oil composition according to claim 1, further comprising at least one selected from the group consisting of an antioxidant, a demulsifier, a rust inhibitor, and a corrosion inhibitor.   The turbine oil composition according to claim 1 or 2, wherein a degree of biodegradation according to the OECD 301B method or the OECD 301C method is 60% or more.   The turbine oil composition according to any one of claims 1 to 3, wherein the turbine oil composition is for hydroelectric power generation equipment.