Electrical insulation oil composition

Abstract

To provide an electrical insulation oil composition having excellent electrical properties and high oxidation stability, which has minimal impact on organic materials in high-voltage electrical equipment and can preserve the natural environment.SOLUTION: An electrical insulation oil composition comprises a base oil (A), wherein the base oil (A) includes a hydrocarbon base oil (A1) having biomass-derived carbon, and the content of the biomass-derived carbon measured by ASTM D6866 is 20 mass% or more based on the total carbon in the electrical insulation oil composition.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an electrical insulating oil composition. [Background technology]

[0002] Electrical insulating oil compositions are compositions used for the purpose of insulating and cooling high-voltage electrical equipment such as transformers, high-voltage cables, high-voltage circuit breakers, and capacitors. Once these devices are put into commercial operation, they are required to be able to be used for a long period of time without maintenance. Therefore, it is necessary for electrical insulating oils to be able to maintain stable electrical properties for a long period of time.

[0003] In recent years, from the viewpoint of preserving the natural environment, there has been an increasing demand for the creation of a recycling-based society, and there is a desire to move away from fossil fuel resources and become so-called carbon neutral. For this reason, the use of raw materials derived from biomass has been attracting attention. Biomass is a renewable, organic resource derived from living organisms, excluding fossil resources. Since biomass-derived raw materials do not affect the concentration of carbon dioxide in the atmosphere, carbon neutrality can be achieved by using biomass-derived raw materials.

[0004] As an example of a composition containing a biomass-derived base oil, Patent Document 1 discloses a hydraulic oil containing a biomass-derived base oil and an antioxidant. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2015 / 192072 Summary of the Invention [Problem to be solved by the invention]

[0006] In the case of conventional hydraulic oils such as those described in Patent Document 1, studies have been conducted to reduce the environmental impact, but the functions required for an electrical insulating oil composition have not been verified. An electrical insulating oil composition is required to have high electrical properties and oxidation stability, and to have little effect on organic materials in high-voltage electrical equipment. An example of such organic materials is rubber used in sealing materials. Additionally, efforts are being made to reduce carbon emissions by using vegetable oil (ester oil). However, the vegetable oil has different properties from the mineral oil that has been widely used up until now, which poses the problem of requiring changes to equipment specifications.

[0007] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide an electrical insulating oil composition that has good electrical properties and high oxidation stability, has little effect on organic materials in high-voltage electrical equipment, and is capable of preserving the natural environment. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention employs the following configuration. [1] An electrical insulating oil composition containing a base oil (A), the base oil (A) comprising a hydrocarbon base oil (A1) having biomass-derived carbon, the content of biomass-derived carbon as measured by ASTM D6866 being 20 mass% or more based on the total carbon in the electrical insulating oil composition. [2] The electrical insulating oil composition according to [1], wherein the content of biomass-derived carbon as measured by ASTM D6866 is 40 mass% or more based on the total carbon in the electrical insulating oil composition. [3] The electrical insulating oil composition according to [1] or [2], further comprising an antioxidant. [4] The electrical insulating oil composition according to [3], wherein the antioxidant contains a phenol compound. Effect of the Invention

[0009] According to the present invention, it is possible to provide an electrical insulating oil composition which has good electrical properties, high oxidation stability, has little effect on organic materials in high-voltage electrical equipment, and is also environmentally friendly. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] (Electrical insulating oil composition) The electrical insulating oil composition of the present embodiment is a composition used for the purpose of insulating and cooling high-voltage electrical equipment such as transformers, high-voltage cables, high-voltage circuit breakers, and capacitors. In the electrical insulating oil composition of this embodiment, the content of biomass-derived carbon as measured by ASTM D6866 is 20 mass % or more, preferably 40 mass % or more, more preferably 60 mass % or more, and even more preferably 80 mass % or more, based on the total carbon in the electrical insulating oil composition. There is no upper limit for the content of carbon derived from biomass as measured by ASTM D6866, but it may be 100% by mass or less, or may be 99% by mass or less.

[0011] ASTM D6866 (Biobased Content Testing Standard) is a standard established to determine the biobased content of solids, liquids, and gases using radioactive carbon (C14) analysis. Since biomass contains a certain amount of radioactive carbon (C14), raw materials derived from biomass also contain radioactive carbon (C14). On the other hand, raw materials derived from fossil resources do not contain radioactive carbon (C14). Therefore, the amount of carbon derived from biomass can be calculated by measuring the concentration of radioactive carbon (C14) contained in an electrical insulating oil composition.

[0012] The electrical insulating oil composition of this embodiment has a kinetic viscosity of 1.0 mm at 40°C. 2 / s or more is preferable, and 3.0 mm 2 / s or more is more preferable, and 5.0 mm 2 It is even more preferable that the ratio is 1 / s or more. The electrical insulating oil composition of this embodiment has a kinetic viscosity of 60 mm at 40°C. 2 / s or less is preferable, and 30 mm 2 / s or less is more preferable, and 13 mm 2 It is even more preferable that the ratio is equal to or less than 1 / s. For example, the kinetic viscosity of the electrical insulating oil composition of this embodiment at 40°C is 1.0 mm 2 / s or more 60mm 2 / s or less is preferable, and 3.0 mm 2 / s or more 30mm 2 / s or less is more preferable, and 5.0 mm 2 / s or more 13mm 2 It is even more preferable that the ratio is equal to or less than 1 / s.

[0013] When the electrical insulating oil composition of this embodiment has a kinetic viscosity at 40° C. that is equal to or greater than the above-mentioned preferable lower limit, leakage of oil from electrical equipment can be further suppressed. When the kinetic viscosity at 40° C. of the electrical insulating oil composition of this embodiment is equal to or less than the above-mentioned preferable upper limit, the cooling properties are further improved.

[0014] In this specification, the kinematic viscosity at 40° C. means a value measured in accordance with JIS K2283:2000 “Crude oil and petroleum products-Determination of kinematic viscosity”.

[0015] The density of the electrical insulating oil composition of this embodiment at 15° C. is 0.50 g / cm 3 It is preferable that the content is 0.60 g / cm or more. 3 More preferably, it is 0.70 g / cm or more. 3 More preferably, it is equal to or greater than this. The density of the electrical insulating oil composition of this embodiment at 15° C. is 1.10 g / cm 3 It is preferable that the concentration is 1.00 g / cm or less. 3 More preferably, it is 0.91 g / cm or less. 3 It is even more preferable that: For example, the density of the electrical insulating oil composition of this embodiment at 15° C. is 0.50 g / cm 3 More than 1.10g / cm 3 It is preferable that the density is 0.60 g / cm or less.3 More than 1.00g / cm 3 More preferably, it is 0.70 g / cm or less. 3 More than 0.91g / cm 3 It is even more preferable that:

[0016] In this specification, the density at 15°C means a value measured in accordance with JIS K2249-1:2011.

[0017] The flash point (PM) of the electrical insulating oil composition of this embodiment is preferably 110° C. or higher, more preferably 120° C. or higher, and even more preferably 130° C. or higher. The upper limit of the flash point (PM) of the electrical insulating oil composition of this embodiment is not particularly limited, but is usually 300° C. or lower, and can be, for example, 280° C. or lower. When the flash point (PM) of the electrical insulating oil composition of this embodiment is equal to or higher than the above-mentioned preferable lower limit, the risk of fire is suppressed and safety is improved.

[0018] In this specification, the flash point (PM) refers to a value measured by the Pensky-Martens closed-cell method defined in JIS K2265-3:2007.

[0019] The pour point of the electrical insulating oil composition of this embodiment is preferably -20°C or lower, more preferably -25°C or lower, and even more preferably -27.5°C or lower.

[0020] When the pour point of the electrical insulating oil composition of the present embodiment is equal to or lower than the above preferred upper limit, deterioration of performance in winter or in cold regions can be further suppressed.

[0021] The lower limit of the pour point of the electrical insulating oil composition of the present embodiment is not particularly limited, but is usually -65°C or higher, and can be, for example, -40°C or higher.

[0022] In this specification, the pour point means a value measured in accordance with JIS K2269:1987.

[0023] The acid value of the electrical insulating oil composition of this embodiment is preferably 0.02 mgKOH / g or less, more preferably 0.01 mgKOH / g or less, and even more preferably 0.005 mgKOH / g or less.

[0024] When the acid value of the electrical insulating oil composition of the present embodiment is equal to or less than the above preferred upper limit, the stability over time is improved.

[0025] The acid value in this specification means a value measured in accordance with JIS K2501:2003.

[0026] The aniline point of the electrical insulating oil composition of this embodiment is preferably 80° C. or higher, more preferably 90° C. or higher, and even more preferably 100° C. or higher.

[0027] When the aniline point of the electrically insulating oil composition of the present embodiment is equal to or higher than the above-mentioned preferable lower limit, the effect on organic materials can be further reduced.

[0028] The upper limit of the aniline point of the electrical insulating oil composition of this embodiment is not particularly limited, but is, for example, preferably 140° C. or lower, more preferably 130° C. or lower, and even more preferably 120° C. or lower.

[0029] The aniline point in this specification means a value measured in accordance with JIS K2256:2013.

[0030] <Base oil (A)> The kinetic viscosity of base oil (A) at 40°C is 1.0mm 2 / s or more is preferable, and 1.5 mm 2 / s or more is more preferable, and 2.0 mm 2 It is even more preferable that the ratio is 1 / s or more. The kinetic viscosity of base oil (A) at 40°C is 60mm 2 / s or less is preferable, and 40 mm 2 / s or less is more preferable, and 25 mm2 It is even more preferable that the ratio is equal to or less than 1 / s. For example, the kinetic viscosity of base oil (A) at 40°C is 1.0 mm 2 / s or more 60mm 2 / s or less is preferable, and 1.5 mm 2 / s or more 40mm 2 / s or less is more preferable, and 2.0 mm 2 / s or more 25mm 2 It is even more preferable that the ratio is equal to or less than 1 / s.

[0031] When the base oil (A) of the electrical insulating oil composition of this embodiment has a kinetic viscosity at 40° C. of at least the above-mentioned preferable lower limit, leakage of oil from electrical equipment can be further suppressed. When the kinematic viscosity at 40° C. of the base oil (A) of the electrical insulating oil composition of this embodiment is equal to or less than the above preferred upper limit, the cooling properties are further improved.

[0032] The base oil (A) comprises a hydrocarbon base oil (A1) having carbon derived from biomass.

[0033] <Hydrocarbon base oil containing biomass-derived carbon (A1)> Specific examples of the hydrocarbon base oil (A1) having biomass-derived carbon (hereinafter also referred to as "component (A1)") include hydrocarbon base oils synthesized from vegetable oils such as palm oil, coconut oil, soybean oil, rapeseed oil, corn oil, and mixtures thereof. Specifically, the vegetable oil (ester) can be used as a raw material to produce a hydrocarbon base oil by chemical reactions (hydrolysis, hydrogenation, dehydration, dimerization, etc.).

[0034] Commercially available examples of the component (A1) include SynNova 4 Base Oil (manufactured by Novvi), SynNova 9 Base Oil (manufactured by Novvi), and NovaSolv 160 (manufactured by Novvi).

[0035] The (A1) component has a biomass-derived carbon content, as measured by ASTM D6866, of preferably 20 mass% or more, more preferably 60 mass% or more, even more preferably 80 mass% or more, and particularly preferably 100 mass%.

[0036] The kinetic viscosity of component (A1) at 40°C is 1.0mm 2 / s or more is preferable, and 1.5 mm 2 / s or more is more preferable, and 2.0 mm 2 It is even more preferable that the ratio is 1 / s or more. The kinetic viscosity of component (A1) at 40°C is 60mm 2 / s or less is preferable, and 40 mm 2 / s or less is more preferable, and 25 mm 2 It is even more preferable that the ratio is equal to or less than 1 / s. For example, the kinetic viscosity of component (A1) at 40°C is 1.0 mm 2 / s or more 60mm 2 / s or less is preferable, and 1.5 mm 2 / s or more 40mm 2 / s or less is more preferable, and 2.0 mm 2 / s or more 25mm 2 It is even more preferable that the ratio is equal to or less than 1 / s.

[0037] When the kinetic viscosity of the component (A1) at 40° C. is at least the above-mentioned preferable lower limit, oil leakage from electrical equipment can be further suppressed. When the kinetic viscosity of the component (A1) at 40° C. is no more than the above preferred upper limit, the cooling properties are further improved.

[0038] In the electrical insulating oil composition of this embodiment, the component (A1) may be used alone, or a plurality of components (A1) may be used in combination. The content of the (A1) component is preferably 50 mass % or more, more preferably 80 mass % or more, and even more preferably 90 mass % or more, based on the total amount of the base oil (A), and may be 100 mass %.

[0039] The base oil (A) may contain a base oil (A2) other than the above-mentioned component (A1).

[0040] <<Base oil (A2) other than component (A1)>> Specific examples of the base oil (A2) other than the above-mentioned component (A1) (hereinafter also referred to as "component (A2)") include synthetic oils and mineral oils.

[0041] ·Synthetic oil Examples of synthetic oils include polyolefins such as poly-α-olefins, alkylbenzenes, and alkylnaphthalenes.

[0042] Mineral oil As the mineral oil, a distillate oil obtained by atmospheric distillation of crude oil can be used. In addition, a lubricating oil fraction obtained by further distilling the distillate oil under reduced pressure and refining the distillate oil by various refining processes can also be used. The refining process may be a suitable combination of hydrorefining, solvent extraction, solvent dewaxing, hydrodewaxing, sulfuric acid washing, clay treatment, etc. Mineral oil can be obtained by combining these refining processes in a suitable order. In addition, a mixture of a plurality of refined oils having different properties obtained by subjecting different crude oils or distillate oils to a combination of different refining processes may be used.

[0043] As the component (A2), the above synthetic oils or mineral oils may be used alone, or a mixture of two or more synthetic oils or mineral oils may be used.

[0044] The content of the base oil (A) in the electrical insulating oil composition of this embodiment is preferably 90 mass % or more, more preferably 92 mass % or more, and even more preferably 95 mass % or more, based on the total amount of the electrical insulating oil composition. The upper limit of the content of the base oil (A) in the electrical insulating oil composition of this embodiment is not particularly limited, but may be, for example, 99 mass % or less, or 98 mass % or less.

[0045] The base oil (A) in the electrical insulating oil composition of this embodiment preferably consists solely of component (A1).

[0046] <Optional ingredients> The electrical insulating oil composition of the present embodiment may contain optional components other than the above-mentioned base oil (A), such as an antioxidant, an antistatic agent, and a pour point depressant. The electrical insulating oil composition in one embodiment is a composition consisting of only a base oil (A) and an antioxidant. The electrical insulating oil composition in one embodiment is a composition consisting only of a base oil (A), an antioxidant, an antistatic agent, and a pour point depressant.

[0047] <Antioxidants> The antioxidant includes an amine compound, a phenol compound, and the like.

[0048] Amine compounds Examples of the amine compound include phenyl-α-naphthylamine, diphenylamine, dialkyldiphenylamine, and p-alkylphenyl-α-naphthylamine.

[0049] Phenyl-α-naphthylamine Examples of phenyl-α-naphthylamine include compounds represented by the following general formula (1).

[0050] [ka] [In formula (1), R 1 represents a hydrogen atom or a linear or branched alkyl group having 1 to 16 carbon atoms.]

[0051] R 1Examples of the linear or branched alkyl group having 1 to 16 carbon atoms in the formula (I) include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, and a hexadecyl group (these alkyl groups may be linear or branched).

[0052] The phenyl-α-naphthylamine represented by the general formula (1) may be a commercially available product or a synthetic product. The synthetic product can be easily synthesized by reacting phenyl-α-naphthylamine with a halogenated alkyl compound having 1 to 16 carbon atoms, or by reacting phenyl-α-naphthylamine with an olefin having 2 to 16 carbon atoms or an olefin oligomer having 2 to 16 carbon atoms, using a Friedel-Crafts catalyst. Examples of the Friedel-Crafts catalyst that can be used include metal halides such as aluminum chloride, zinc chloride, and iron chloride; and acid catalysts such as sulfuric acid, phosphoric acid, phosphorus pentoxide, boron fluoride, acid clay, and activated clay.

[0053] Diphenylamine, dialkyldiphenylamine Specific examples of diphenylamine and dialkyldiphenylamine include compounds represented by the following general formula (2).

[0054] [ka] [In formula (2), R 2 and R 3 each independently represents a hydrogen atom or an alkyl group having 1 to 16 carbon atoms.]

[0055] R 2 and R 3Specific examples of the alkyl group represented by the formula (I) include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, and a hexadecyl group (these alkyl groups may be linear or branched). Among these, R 2 and R 3 As the C3 or C4 olefin, a branched alkyl group having 3 to 16 carbon atoms is preferred, and 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 preferred. Specific examples of the C3 or C4 olefin include propylene, 1-butene, 2-butene, and isobutylene, and propylene or isobutylene is preferred because of their excellent solubility. 2 or R 3 As the branched olefin group, an isopropyl group derived from propylene, a tert-butyl group derived from isobutylene, a branched hexyl group derived from a propylene dimer, a branched octyl group derived from an isobutylene dimer, a branched nonyl group derived from a propylene trimer, a branched dodecyl group derived from an isobutylene trimer, a branched dodecyl group derived from a propylene tetramer, or a branched pentadecyl group derived from a propylene pentamer are even more preferred, as they provide even better solubility, and a tert-butyl group derived from isobutylene, a branched hexyl group derived from a propylene dimer, a branched octyl group derived from an isobutylene dimer, a branched nonyl group derived from a propylene trimer, a branched dodecyl group derived from an isobutylene trimer, or a branched dodecyl group derived from a propylene tetramer are most preferred.

[0056] In the electrical insulating oil composition of the present embodiment, one amine compound may be used alone, or a mixture of multiple amine compounds may be used.

[0057] Phenolic compounds Specific examples of phenol compounds include 2,6-di-t-butyl-4-methylphenol (DBPC), 2,6-di-t-butylphenol, 4,4'-methylenebis(2,6-di-t-butylphenol), 4,4'-butylidenebis(3-methyl-6-t-butylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 2,2'-methylenebis(4-methyl-6-t-butylphenol), 4,4'-isopropylidenebisphenol, 2,4-dimethyl-6-t-butylphenol, tetrakis[methylene-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]methane, 1,1,3-tris(2-methyl-4-hydroxy- 5-t-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, 2,6-di-t-butyl-4-ethylphenol, 2,6-bis(2'-hydroxy-3'-t-butyl-5'-methylbenzyl)-4-methylphenol, bis[2-(2-hydroxy-5-methyl-3-t-butylbenzyl)-4-methyl-6-t-butylphenyl]terephthalate, triethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6-hexanediol-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate].

[0058] Of the above phenol compounds, the compound represented by the following general formula (3) is preferred.

[0059] [ka] [In formula (3), R 4 is a hydrocarbon group which may have a substituent.

[0060] R 4 The hydrocarbon group in is preferably a hydrocarbon group having 1 to 25 carbon atoms, more preferably a hydrocarbon group having 1 to 15 carbon atoms, and even more preferably a hydrocarbon group having 1 to 10 carbon atoms. The substituent that the hydrocarbon group may have may be, for example, a monovalent substituent such as a halogenated alkyl group, an amino group, or a hydroxy group, or a divalent substituent such as an oxygen atom (ether bond: -O-) or an ester bond (-C(=O)-O-).

[0061] R 4 As the hydrocarbon group in, among the above, an alkyl group having 1 to 5 carbon atoms is preferable, an alkyl group having 1 to 3 carbon atoms is more preferable, and a linear alkyl group having 1 to 3 carbon atoms is even more preferable.

[0062] In the electrical insulating oil composition of the present embodiment, a single type of phenol compound may be used alone, or a mixture of multiple phenol compounds may be used.

[0063] Of the above, the antioxidant in the electrical insulating oil composition of the present embodiment preferably contains a phenol compound, and more preferably contains a compound represented by the above general formula (3).

[0064] In the electrical insulating oil composition of the present embodiment, one type of antioxidant may be used alone, or a mixture of multiple antioxidants may be used. The content of the antioxidant is preferably 0.01 mass % or more, more preferably 0.03 mass % or more, and even more preferably 0.05 mass % or more, based on the total amount of the electrical insulating oil composition of this embodiment. The content of the antioxidant is preferably 1.0 mass % or less, more preferably 0.5 mass % or less, and even more preferably 0.3 mass % or less, based on the entire electrical insulating oil composition of this embodiment. For example, the content of the antioxidant is preferably 0.01 mass % or more and 1.0 mass % or less, more preferably 0.03 mass % or more and 0.5 mass % or less, and even more preferably 0.05 mass % or more and 0.3 mass % or less, based on the entire electrical insulating oil composition of this embodiment.

[0065] When the content of the antioxidant is equal to or more than the above preferable lower limit, the oxidation stability is further improved. When the content of the antioxidant is equal to or less than the above preferable upper limit, the electrical properties are further improved.

[0066] <Antistatic agent> The antistatic agent includes benzotriazole and benzotriazole derivatives.

[0067] In the electrically insulating oil composition of the present embodiment, one type of antistatic agent may be used alone, or a mixture of multiple antistatic agents may be used. The content of the antistatic agent is preferably 1 ppm by mass or more, more preferably 3 ppm by mass or more, and even more preferably 5 ppm by mass or more, based on the entire electrical insulating oil composition of this embodiment. The content of the antistatic agent is preferably 50 ppm by mass or less, more preferably 40 ppm by mass or less, and even more preferably 30 ppm by mass or less, based on the entire electrical insulating oil composition of this embodiment. For example, the content of the antistatic agent is preferably 1 ppm by mass or more and 50 ppm by mass or less, more preferably 3 ppm by mass or more and 40 ppm by mass or less, and even more preferably 5 ppm by mass or more and 30 ppm by mass or less, relative to the entire electrical insulating oil composition of this embodiment.

[0068] When the content of the antistatic agent is equal to or more than the above preferable lower limit, the antistatic effect is further improved. When the content of the antistatic agent is equal to or less than the above preferable upper limit, the electrical properties are further improved.

[0069] <Pour point depressant> The pour point depressant may, for example, be a polymethacrylate-based polymer that is compatible with the base oil (A).

[0070] In the electrical insulating oil composition of the present embodiment, one type of pour point depressant may be used alone, or a mixture of multiple pour point depressants may be used. The content of the pour point depressant is preferably 0.001 mass % or more, more preferably 0.003 mass % or more, and even more preferably 0.005 mass % or more, based on the entire electrical insulating oil composition of this embodiment. The content of the pour point depressant is preferably 0.1 mass % or less, more preferably 0.07 mass % or less, and even more preferably 0.05 mass % or less, based on the entire electrical insulating oil composition of this embodiment. For example, the content of the pour point depressant is preferably 0.001 mass % or more and 0.1 mass % or less, more preferably 0.003 mass % or more and 0.07 mass % or less, and even more preferably 0.005 mass % or more and 0.05 mass % or less, based on the entire electrical insulating oil composition of this embodiment.

[0071] When the content of the pour point depressant is equal to or more than the above preferable lower limit, the fluidity at low temperatures is further improved. When the content of the pour point depressant is equal to or less than the above preferable upper limit, the electrical properties are further improved. EXAMPLES

[0072] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0073] <Formulation of Electrical Insulating Oil Composition> (Examples 1 to 5) The electrical insulating oil compositions of Examples 1 to 5 were prepared by blending the components in the blending ratios shown in Tables 1 and 2. The numerical value for component (A) means the content ratio (mass%) of each base oil relative to the total amount of component (A), and the numerical values ​​for components other than component (A) mean the content (mass%) of each component relative to the total amount of the electrical insulating oil composition. Therefore, the content of component (A) relative to the total amount of the electrical insulating oil composition is the remainder obtained by subtracting the contents of components other than component (A) from 100 mass%.

[0074] (1) Base oil (A) A1-1: 100% plant-derived hydrocarbon-based lubricant base oil (100% plant-derived hydrocarbon-based lubricant base oil (product name "SynNova 4 Base Oil", manufactured by Novvi, 40°C kinematic viscosity: 19.74 mm 2 / s, 100℃ kinematic viscosity: 4.382mm 2 / s, viscosity index: 135, density: 0.8192g / cm 3 , flash point (PM): 220°C, pour point: <-45°C, aniline point: 123°C). A1-2: 100% plant-derived hydrocarbon lubricant base oil (product name "NovaSolv 160", manufactured by Novvi, kinematic viscosity at 40°C: 2.723 mm 2 / s, density: 0.7841g / cm 3 , flash point (PM): 136°C, pour point: -15°C, aniline point: 78.5°C). A1-3: 100% plant-derived hydrocarbon lubricant base oil (product name "NovaSolv 9", manufactured by Novvi, kinematic viscosity at 40°C: 57.15 mm 2 / s, 100℃ kinematic viscosity: 9.398mm 2 / s, density: 0.8337g / cm 3 , flash point: (PM): 258°C, pour point: -30°C, aniline point: 138.6°C).

[0075] (2) Additives X-1: 2,6-di-t-butyl-4-methylphenol X-2: Benzotriazole X-3: Polyalkyl methacrylate

[0076] (Comparative Examples 1 to 4) Comparative Example 1: A mineral oil having the physical properties shown in Table 1 was prepared. Comparative Example 2: A commercially available electrical insulating oil composition A containing at least a natural ester (rapeseed oil) and 2,6-di-t-butyl-4-methylphenol having the physical properties shown in Table 1 was prepared. Comparative Example 3: A commercially available electrical insulating oil composition B containing at least a synthetic ester oil and 2,6-di-t-butyl-4-methylphenol having the physical properties shown in Table 1 was prepared. Comparative Example 4: A commercially available electrical insulating oil composition C having the physical properties shown in Table 1 and containing at least a plant-derived ester and 2,6-di-t-butyl-4-methylphenol was prepared.

[0077] <Evaluation of electrical insulating oil composition properties> The electrical insulating oil compositions of Examples 1 to 5 and the electrical insulating oil compositions of Comparative Examples 1 to 4 are shown in Tables 1 and 2. The physical properties shown in Tables 1 and 2 were determined in accordance with the test methods shown below.

[0078] Biobased content: ASTM D6866 ·Density (15℃): JIS K2249-1:2011 Flash point (PM: Pensky Martens closed cup): JIS K2265-3:2007 ·Kinematic viscosity: JIS K2283:2000 ·Pour point: JIS K2269:1987 ·Acid value: JIS K2501:2003 Aniline point: JIS K2256:2013

[0079] Volume resistivity: JIS C2101:2010 -Dielectric tangent: JIS C2101:2010 Breakdown voltage (BDV): JIS C2101:2010 Oxidation stability: JIS C2101:2010

[0080] [Table 1]

[0081] [Table 2]

[0082] As shown in Tables 1 and 2, the electrical insulating oil compositions of the Examples containing the hydrocarbon base oil (A1) had a high bio-based degree and were able to protect the natural environment, while having less of an effect on the organic materials of high-voltage electrical equipment and also having better electrical properties than the electrical insulating oil compositions of Comparative Examples 2 to 4 containing the ester base oil. Furthermore, the electrical insulating oil compositions of the Examples had a high degree of bio-based content and were able to preserve the natural environment, while also satisfying the JIS C2320 Type 1 No. 4 standards for electrical properties and oxidation stability, maintaining levels equivalent to those of the electrical insulating oil composition of Comparative Example 1 which consisted of conventional mineral oil.

Claims

1. An electrical insulating oil composition containing a base oil (A), The base oil (A) comprises a hydrocarbon base oil (A1) having carbon derived from biomass, An electrical insulating oil composition, having a biomass-derived carbon content, as measured by ASTM D6866, of 20 mass% or more based on the total carbon content in the electrical insulating oil composition.

2. 2. The electrical insulating oil composition according to claim 1, wherein the content of biomass-derived carbon as measured by ASTM D6866 is 40 mass% or more based on the total carbon in the electrical insulating oil composition.

3. The electrical insulating oil composition according to claim 1 or 2, further comprising an antioxidant.

4. The electrical insulating oil composition of claim 3 , wherein the antioxidant comprises a phenolic compound.

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