WO2011080991A1

WO2011080991A1 - Base oil for cooling of device, device-cooling oil containing the base oil, device to be cooled by the cooling oil, and device cooling method using the cooling oil

Info

Publication number: WO2011080991A1
Application number: PCT/JP2010/071817
Authority: WO
Inventors: 坪内　俊之
Original assignee: 出光興産株式会社
Priority date: 2009-12-28
Filing date: 2010-12-06
Publication date: 2011-07-07
Also published as: CN102695782A; EP2520637A4; KR20120112666A; EP2520637A1

Abstract

Disclosed is a base oil for cooling a device, which contains 30 mass% or more of at least one compound selected from an oleyl ester (an oleic acid ester and an oleyl alcohol ester) and an oleyl ether, wherein each of the oleyl ester and the oleyl ether has a terminal methyl group, a methylene group and an ether group in the total number of 23 or more in the main chain thereof, the total number of methyl branches and ethyl branches in the oleyl ester and the oleyl ether is 1 or less, and the kinematic viscosity of the base oil is 4 to 30 mm²/s or less at 40˚C. A device-cooling oil containing the base oil has excellent electrical insulation properties and excellent heat conductivity and is therefore suitable for cooling a motor, a battery, an inverter, an engine, an electric cell or the like in an electric-powered car or a hybrid car.

Description

Equipment cooling base oil, equipment cooling oil blended with the base oil, equipment cooled by the cooling oil, and equipment cooling method using the cooling oil

The present invention relates to an equipment cooling base oil, equipment cooling oil obtained by blending the base oil, equipment cooled by the cooling oil, and equipment cooling method using the cooling oil.

Due to the high performance of electric and hybrid vehicles, the output density of motors has increased and the amount of heat generated has also increased. For this reason, various designs have been made in the motor design, such as not only improving the heat resistance of coils and magnets, but also reducing the amount of heat generated by increasing the efficiency of the motor.
Motor cooling methods can be broadly divided into air cooling, water cooling and oil cooling. Among these, the air cooling method is excellent in that it is not necessary to prepare a cooling medium, but it is difficult to ensure a large cooling capacity. The water-cooling method is excellent in cooling because of the high thermal conductivity of water, but because of the conductivity, the motor coil cannot be directly cooled, and the necessity to stretch the cooling pipes arises, so the cooling device becomes large There is.
In contrast to these cooling systems, the oil cooling system has excellent cooling efficiency and low electrical conductivity, so that the motor can be directly cooled and a compact design can be achieved. Therefore, if it is necessary to lubricate the rotating member at the same time, the motor cooling oil can be used as the dual-purpose oil by forming the same package. For example, in a hybrid vehicle, a mechanism for circulating a transmission oil and simultaneously cooling a motor has been put into practical use. In addition, the wheel drive motor of an electric vehicle has been devised in a design that serves as both lubrication of a planetary gear and motor coil cooling by circulating lubricating oil.

As the dual-purpose oil that simultaneously performs lubrication of the transmission and the motor cooling as described above, for example, (A) a hydrocarbon group-containing zinc dithiophosphate, (B) a triaryl phosphate, and ( C) A lubricating oil composition comprising at least one of triarylthiophosphates has been proposed (see Patent Document 1). The heat transfer coefficient using a lubricating base oil having a urea adduct value of 4% by mass or less, a kinematic viscosity at 40 ° C. of 25 mm ² / s or less, and a viscosity index of 100 or more is 720 W / m ^2. A lubricating oil composition (see Patent Document 2) having a temperature of ℃ or higher or an ester-based synthetic oil in an amount of 10% by mass to 100% by mass based on the total amount of the base oil, a kinematic viscosity at 40 ° C of less than 15 mm ² / s, a viscosity The same applies to a lubricating oil composition (see Patent Document 3) having a heat transfer coefficient of 780 W / m ² · ° C. or higher using a lubricating base oil having an index of 120 or higher and a density of 0.85 g / cm ³ or higher at 15 ° C. It has been proposed as a combined oil. In each of the above-mentioned documents, it is described that the proposed lubricating oil composition is excellent in electric insulation, cooling and lubricity, and can be suitably used for an electric motor-equipped vehicle such as an electric vehicle or a hybrid vehicle. is there.

WO2002 / 097017 JP 2009-161604 A JP 2009-242547 A

However, Patent Document 1 mentions only that the viscosity of the lubricating oil composition is low, and does not disclose any data regarding the cooling performance. Also, neopentyl glycol 2-ethylhexanoic acid diester and alkylbenzene described as base oils in the examples cannot be said to have low thermal conductivity and good cooling properties. Patent Document 2 describes in paragraph [0020] of the specification that “as a urea adduct, a component that deteriorates thermal conductivity is collected accurately and reliably”. . That is, although the urea adduct component is mentioned as a component that deteriorates the thermal conductivity, it is the opposite from the actual thermal conductivity aspect, and “a component with a long paraffin main chain has poor thermal conductivity”. This view seems to be wrong. Therefore, it remains doubtful whether Patent Document 2 discloses a lubricating oil composition having excellent cooling performance. Further, ester compounds specifically disclosed in Patent Document 3 are azelaic acid di-2-ethylhexyl, neopentyl glycol 2-ethylhexanoic acid diester, and oleic acid 2-ethylhexyl, which are not preferable because of low thermal conductivity. .

Therefore, an object of the present invention is to provide a base oil for equipment cooling excellent in electrical insulation and thermal conductivity, equipment cooling oil blended with the base oil, equipment cooled by the cooling oil, and equipment using the cooling oil It is to provide a cooling method.

There is a “heat transfer coefficient (unit area, unit temperature, amount of heat transfer per unit time)” as a scale indicating the cooling performance by the fluid, and the larger this value, the better the cooling performance. However, since the heat transfer coefficient is not a physical property value but a value that changes depending on conditions such as a flow velocity and a material, a design device has been devised to increase this value.
On the other hand, in order to increase the heat transfer coefficient with a device on the fluid side, the Nusselt number, Reynolds number, and Prandtl number are related, so the physical properties of the fluid are kinematic viscosity, thermal conductivity, specific heat, and density. Affect. Specifically, the smaller the kinematic viscosity, the greater the thermal conductivity, specific heat, and density, and the better the cooling performance as a fluid. Therefore, conventionally, it has been studied to improve the cooling performance by reducing the viscosity of the fluid (lubricating oil or the like). However, in the case of lubricating oil, the cooling performance improves when the viscosity is lowered, but a sufficient oil film thickness cannot be secured, resulting in poor lubrication. Therefore, the necessary minimum limit viscosity is determined by the condition of the lubrication part such as a transmission. Therefore, even with the same kinematic viscosity, a lubricating oil with higher thermal conductivity, specific heat, and density has better cooling performance. For example, the heat transfer coefficient due to forced convection of a plate with uniform temperature is proportional to the thermal conductivity of 2/3, specific heat of 1/3, and density of 1/3. Is the largest.

Therefore, a base oil with high thermal conductivity is desired as a cooling oil used in equipment such as motors. However, there have been no studies or knowledge on the correlation between the molecular structure of the base oil and the thermal conductivity. It was. Basic low molecular weight compounds are listed in the chemical handbook, that is, are known to have high thermal conductivity of alcohols such as glycerin, ethylene glycol, and methanol. However, polar compounds such as alcohol have a low volume resistivity (poor electrical insulation) and cannot be used as a cooling oil for directly cooling devices such as motors. Also, lubricity as a lubricating oil cannot be expected.
On the other hand, the present inventor has intensively studied from the viewpoint of molecular design, and found that a compound having a predetermined molecular structure is excellent in cooling property, electrical insulation property and lubricity.
That is, the present invention provides the following equipment cooling base oil, equipment cooling oil obtained by blending the base oil, equipment cooled by the cooling oil, and equipment cooling method using the cooling oil. .

(1) An equipment cooling base oil containing at least one of oleyl ester (oleic acid ester, oleyl alcohol ester) and oleyl ether in an amount of 30% by mass or more, wherein the oleyl ester and the oleyl ether are mainly The total number of terminal methyl groups, methylene groups and ether groups in the chain is 23 or more, the total number of methyl branches and ethyl branches in the oleyl ester and the oleyl ether is 1 or less, and the 40 ° C. kinematic viscosity of the base oil is 4 mm ² / s or more and 30 mm ² / s or less.
(2) The above-described base oil for motor cooling contains 50% by mass or more of the oleyl ester and the oleyl ether.
(3) An equipment cooling base oil containing at least one of aliphatic monoesters and aliphatic monoethers in an amount of 30% by mass or more in the main chain of the aliphatic monoesters and the aliphatic monoethers The total number of terminal methyl groups, methylene groups, and ether groups of is 18 or more, and the total number of methyl branches and ethyl branches in the aliphatic monoester and the aliphatic monoether is 2 or less. A base oil for equipment cooling having a viscosity of 4 mm ² / s or more and 30 mm ² / s or less.
(4) In the above-described base oil for equipment cooling, at least one of the aliphatic monoester and the aliphatic monoether has a chain structure.
(5) Equipment cooling base oil containing at least one of aliphatic diesters and aliphatic diethers in an amount of 30% by mass or more, and terminal methyl groups in the main chain of the aliphatic diesters and the aliphatic diethers The total number of methylene groups and ether groups is 20 or more, the total number of methyl branches and ethyl branches in the aliphatic diester and the aliphatic diether is 2 or less, and the 40 ° C. kinematic viscosity of the base oil is 4 mm ² / s. As mentioned above, it is 30 mm < ² > / s or less, The base oil for apparatus cooling characterized by the above-mentioned.
(6) Aliphatic triester, aliphatic triether, aliphatic tri (ether ester), aliphatic tetraester, aliphatic tetraether, aliphatic tetra (ether ester), aromatic diester, aromatic diether, and aromatic A base oil for equipment cooling containing 30% by mass or more of at least any one of di (ether esters), wherein each ester, each ether, and a terminal methyl group in the main chain in each ether ester, The total number of methylene groups and ether groups is 18 or more, the total number of methyl branches and ethyl branches in each ester, each ether and each ether ester is 1 or less, and the 40 ° C. kinematic viscosity of the base oil is 4 mm ² The base oil for equipment cooling characterized by being at least / s and not more than 30 mm ² / s.
(7) A base oil for equipment cooling, wherein the base oil for equipment cooling described above has a thermal conductivity at 25 ° C of 0.142 W / (m · K) or more.
(8) A base oil for equipment cooling, wherein the volume resistivity at 25 ° C. is 10 ¹⁰ Ω · cm or more in the base oil for equipment cooling described above.
(9) An equipment cooling oil comprising the equipment cooling base oil described above.
(10) A device that is cooled by the above-described device cooling oil.
(11) The above-described device is for an electric vehicle or a hybrid vehicle.
(12) The device described above, wherein the device is at least one of a motor, a battery, an inverter, an engine, and a battery.
(13) A device cooling method using the above-described device cooling oil.

The equipment cooling oil obtained by blending the equipment cooling base oil of the present invention is excellent in electrical insulation and thermal conductivity, so that motors, batteries, inverters, engines, batteries, etc. mounted on electric cars, hybrid cars, etc. Suitable for cooling.

Hereinafter, the base oil for equipment cooling in each embodiment of the present invention, the equipment cooling oil blended with the base oil, the equipment cooled by the cooling, and the equipment cooling method using the cooling oil will be described.

<First Embodiment>
The base oil for equipment cooling (hereinafter also simply referred to as “base oil”) according to the first embodiment of the present invention is based on at least one of oleyl ester (oleic acid ester, oleyl alcohol ester) and oleyl ether. Ingredients.
Further, in the oleyl ester and the oleyl ether, the total number of terminal methyl groups, methylene groups, and ether groups in the main chain is 23 or more, and the total number of methyl branches and ethyl branches in the molecule is 1 or less. Here, the main chain refers to the longest chain structure in the molecule.
The first embodiment of the present invention will be described in detail below.

In order to improve the thermal conductivity of liquid molecules, it is important to improve the transfer of thermal vibration energy due to collisions between molecules and to design the molecule so that vibration energy does not diffuse within the molecules. In order to increase the collision frequency between molecules, it is effective to lengthen the main chain of the molecule and widen the movable range of the molecule end by the rotational motion between carbon-carbon bonds. Specifically, short methyl branches and ethyl branches that diffuse vibrational energy are reduced so that vibrational energy is not diffused in the molecule and remains concentrated in the molecular main chain. The methyl group and ethyl group are also disadvantageous for collision (energy transfer) with adjacent molecules because of their small movable range. As a molecule having such a structure, an ester or ether having a long chain structure can be considered.

Therefore, in this embodiment, an oleyl ester or oleyl ether in which the total number of terminal methyl groups, methylene groups, and ether groups in the main chain is 23 or more, and the total number of methyl branches and ethyl branches in the molecule is 1 or less, Used as the main component of base oil. Further, from the viewpoint of improving the cooling performance, the number of methylene groups in the oleyl ester or oleyl ether described above is preferably 22 or more, and more preferably 24 or more.
Furthermore, the above oleyl ester and oleyl ether preferably have a chain structure as a whole from the viewpoint of improving the cooling performance as a base oil, and more preferably a linear structure.

Such an oleyl ester can be obtained by a generally known ester production method, and is not particularly limited. For example, dehydration condensation reaction between oleic acid and alcohol, dehydration condensation reaction between carboxylic acid and oleyl alcohol, condensation reaction between oleic acid halide and alcohol, condensation reaction between carboxylic acid halide and oleyl alcohol, or transesterification reaction Etc. For example, a raw material alcohol having a long linear alkyl chain or a raw material carboxylic acid having a long linear alkyl chain is used, and the total number of terminal methyl groups, methylene groups, and ether groups in the main chain, which is the longest chain portion of the molecule, is 23. As mentioned above, it is preferable to synthesize by reacting so that the total number of short alkyl side chains (methyl branch, ethyl branch) in the molecule is 1 or less.

Examples of the raw material carboxylic acid include oleic acid, n-hexanoic acid, n-heptanoic acid, n-octanoic acid, n-nonanoic acid, n-decanoic acid, n-undecanoic acid, n-dodecanoic acid, n-tridecanoic acid, n-tetradecanoic acid, and ethylhexane. Examples thereof include monocarboxylic acids such as acid, butyloctanoic acid, pentylnonanoic acid, hexyldecanoic acid, heptylundecanoic acid, octyldodecanoic acid, methylheptadecanoic acid, and benzoic acid.

Examples of the starting alcohol include oleyl alcohol, n hexanol, n heptanol, n octanol, n nonanol, n decanol, n undecanol, n dodecanol, n tridecanol, n tetradecanol, ethyl hexanol, butyl octanol, pentyl nonanol, Hexyl decanol, heptyl undecanol, octyl dodecanol, methyl heptadecanol, benzyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, Diethylene glycol monopropyl ether, diethylene glycol Monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, and triethylene glycol monobutyl ether.
As the esterification catalyst, a catalyst such as titanium tetraisopropoxide may be used, or no catalyst may be used.
The oleyl ether described above may be produced by a general ether production method such as an ordinary Williamson ether synthesis method, and is not particularly limited.

The base oil of the present embodiment contains 30% by mass or more of at least one of the above-described esters and ethers, but the content as the base oil is preferably 50% by mass or more, and 60% by mass or more. More preferably, it is more preferably 70% by mass or more, and particularly preferably 80% by mass or more. If a base oil having a total content of the above-described ester or ether of less than 30% by mass is used, the cooling performance may not be sufficiently exhibited. Of course, you may use the base oil of this embodiment independently (100 mass%) as a base oil for apparatus cooling.

The base oil of this embodiment has a kinematic viscosity at 40 ° C. of 4 mm ² / s or more and 30 mm ² / s or less, preferably 4 mm ² / s or more and 20 mm ² / s or less. When the 40 ° C. kinematic viscosity is less than 4 mm ² / s, for example, when used as a combined oil for a motor and a transmission, the lubricity may be insufficient. On the other hand, if the 40 ° C. kinematic viscosity exceeds 30 mm ² / s, the cooling performance may be insufficient, and there may be a problem in the system circulation as cooling oil for motors and the like.

The base oil of this embodiment preferably has a thermal conductivity at 25 ° C. of 0.142 W / (m · K) or more from the viewpoint of cooling properties, and more preferably 0.144 W / (m · K) or more. It is.
The base oil of the present embodiment is preferably a volume resistivity at 25 ° C. from the viewpoint of electrical insulation is ^{10 10} Omega · cm or more, more preferably ^{10 11} Omega · cm or more, ^{10 12} More preferably, it is Ω · cm or more, and particularly preferably 10 ¹³ Ω · cm or more.

As base oil of this embodiment, other components (base oil) can also be mixed and used for the above-mentioned ester and ether. In that case, there are no particular limitations on the types of other components, but components that do not impair the above-described viscosity range and that do not impair the cooling performance, insulating properties, and lubricity are mixed to such an extent that the effects of the present invention are not impaired. There is a need.
Preferred examples of such other components include mineral oil and synthetic oil. Examples of the mineral oil include naphthenic mineral oil, paraffinic mineral oil, GTL mineral oil, WAX isomerized mineral oil, and the like. Specific examples include light neutral oil, medium neutral oil, heavy neutral oil, bright stock and the like by solvent refining or hydrogenation refining.
Synthetic oils include polybutene or its hydride, poly α-olefin (1-octene oligomer, 1-decene oligomer, etc.) or its hydride, α-olefin copolymer, alkylbenzene, polyol ester, dibasic acid ester, poly Examples thereof include oxyalkylene glycol, polyoxyalkylene glycol ester, polyoxyalkylene glycol ether, hindered ester, and silicone oil.

The equipment cooling oil comprising the base oil of this embodiment described above can be suitably used for cooling motors, batteries, inverters, engines, batteries, and the like of electric vehicles and hybrid vehicles. Further, since the 40 ° C. viscosity of the base oil is also in a predetermined range, it is excellent in lubricity and is preferable as a dual-purpose oil that also lubricates planetary gears, transmissions, and the like.
In addition, various additives can be mix | blended with the apparatus cooling oil of this embodiment in the range which does not inhibit the objective of this invention. For example, viscosity index improvers, antioxidants, detergent dispersants, friction modifiers (oiliness agents, extreme pressure agents), antiwear agents, metal deactivators, pour point depressants, and antifoaming agents are required It can be blended accordingly. However, when equipment cooling oil is used as a dual-purpose oil, care should be taken so as to have a blended formulation that exhibits lubricating performance without impairing electrical insulation. Therefore, as equipment cooling oil, the thermal conductivity at 25 ° C. is 0.142 W / (m · K) or more, the volume resistivity at 25 ° C. is 10 ¹⁰ Ω · cm or more, and the kinematic viscosity at 40 ° C. It is desirable that the formulation is determined so that it is 4 mm ² / s or more and 30 mm ² / s or less.

Examples of the viscosity index improver include non-dispersed polymethacrylate, dispersed polymethacrylate, olefin copolymer (eg, ethylene-propylene copolymer), dispersed olefin copolymer, styrene copolymer. (For example, styrene-diene hydrogenated copolymer). The mass average molecular weight of these viscosity index improvers is preferably 5,000 or more and 300,000 or less for, for example, dispersed and non-dispersed polymethacrylates. In the case of an olefin copolymer, about 800 or more and 100,000 or less are preferable. These viscosity index improvers can be blended alone or in any combination of two or more, but the blending amount is preferably in the range of 0.1% by mass or more and 20% by mass or less based on the total amount of cooling oil. .

Antioxidants include amine-based antioxidants such as alkylated diphenylamine, phenyl-α-naphthylamine, alkylated phenyl-α-naphthylamine, 2,6-di-t-butylphenol, 4,4′-methylenebis (2, 6-di-t-butylphenol), isooctyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, n-octadecyl-3- (3,5-di-t-butyl-4- Phenol antioxidants such as hydroxyphenyl) propionate, sulfur antioxidants such as dilauryl-3,3′-thiodipropionate, phosphorus antioxidants such as phosphite, and molybdenum antioxidants. . These antioxidants can be contained alone or in any combination of two or more, but usually two or more combinations are preferable, and the blending amount is 0.01% by mass or more based on the total amount of the cooling oil. The mass% or less is preferable.

Examples of cleaning dispersants include metal detergents such as alkaline earth metal sulfonates, alkaline earth metal phenates, alkaline earth metal salicylates, alkaline earth metal phosphonates, alkenyl succinimides, benzyl amines, alkyl polyamines, alkenyl succinates. Examples include ashless dispersants such as acid esters. These detergent dispersants may be used alone or in combination of two or more. The blending amount is preferably 0.1% by mass or more and 30% by mass or less based on the total amount of cooling oil.

Examples of friction modifiers and antiwear agents include sulfur compounds such as sulfurized olefins, dialkyl polysulfides, diarylalkyl polysulfides, diaryl polysulfides, phosphate esters, thiophosphate esters, phosphite esters, alkyl hydrogen phosphites, phosphate esters. Phosphorus compounds such as amine salts and phosphite amine salts, chlorinated oils and fats, chlorinated paraffins, chlorinated fatty acid esters, chlorinated fatty acid and other chlorinated compounds, alkyl or alkenyl maleic acid esters, alkyl or alkenyl succinic acid esters Ester compounds such as alkyl, alkenyl maleic acid, organic acid compounds such as alkyl or alkenyl succinic acid, naphthenate, zinc dithiophosphate (ZnDTP), dithiocarbamine Zinc (ZnDTC), sulfurized oxymolybdenum organo phosphorodithioate (MoDTP), and an organic metal-based compounds such as sulfurized oxymolybdenum dithiocarbamate (MoDTC). The blending amount is preferably 0.1% by mass or more and 5% by mass or less based on the total amount of cooling oil.

Examples of the metal deactivator include benzotriazole, triazole derivatives, benzotriazole derivatives, thiadiazole derivatives, and the like, and the blending amount is preferably 0.01% by mass or less and 3% by mass or less based on the total amount of the cooling oil.
Examples of the pour point depressant include ethylene-vinyl acetate copolymer, condensate of chlorinated paraffin and naphthalene, condensate of chlorinated paraffin and phenol, polymethacrylate, polyalkylstyrene, etc. Methacrylate is preferably used. These blending amounts are preferably 0.01% by mass or more and 5% by mass or less based on the total amount of the cooling oil.
As the antifoaming agent, liquid silicone is suitable, for example, methyl silicone, fluorosilicone, polyacrylate and the like are suitable. A preferable blending amount of these antifoaming agents is 0.0005% by mass or more and 0.01% by mass or less based on the total amount of cooling oil.

<Example of the first embodiment>
Next, although a 1st embodiment is described still in detail by an example, this embodiment is not limited at all by these examples.
Specifically, various base oils as shown in Table 1 were prepared and subjected to various evaluations. The base oil preparation method and evaluation method (physical property measurement method) are as follows.

[Example 1]
In a four-necked flask equipped with a 500 mL Dean-Stark apparatus, 127 g of oleic acid (reagent manufactured by Tokyo Chemical Industry Co., Ltd.), 145 g of oleyl alcohol (reagent manufactured by Tokyo Chemical Industry Co., Ltd.), 100 mL of mixed xylene (reagent manufactured by Tokyo Chemical Industry Co., Ltd.) Then, 0.1 g of titanium tetraisopropoxide (a reagent manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the mixture was reacted at 140 ° C. for 2 hours while distilling off water while stirring under a nitrogen stream. Thereafter, washing with a saturated saline solution and washing with a 0.1 N aqueous sodium hydroxide solution were performed three times each, followed by drying over anhydrous magnesium sulfate (a reagent manufactured by Tokyo Chemical Industry Co., Ltd.). After filtering the magnesium sulfate, excess raw material alcohol was distilled off to obtain 215 g of oleyl oleate. Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of this compound were measured. The results are shown in Table 1. The results are also shown in Table 1 for the following examples and comparative examples.

[Example 2]
184 g of oleic acid n-dodecyl was obtained in the same manner as in Example 1 except that 101 g of n-dodecyl alcohol (a reagent manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of 145 g of oleyl alcohol. Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of this compound were measured.

Example 3
It carried out like Example 1 except having used 71 g of n octyl alcohol (Tokyo Chemical Industry Co., Ltd. reagent) instead of 145 g of oleyl alcohol, and obtained 162 g of n octyl oleates. Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of this compound were measured.

Example 4
16-Methylheptadecyl oleate in the same manner as in Example 1 except that 147 g of 16-methylheptadecanol (trade name: Isostearyl Alcohol EX manufactured by Higher Alcohol Industry Co., Ltd.) was used instead of 145 g of oleyl alcohol. 212 g were obtained. Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density ratio) of this compound were measured.

Example 5
The same procedure as in Example 1 was performed except that 65 g of n-octanoic acid (a reagent manufactured by Tokyo Chemical Industry Co., Ltd.) and 107 g of oleyl alcohol were used instead of 127 g of oleic acid and 145 g of oleyl alcohol, and 143 g of oleyl n-octanoate. Got. Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of this compound were measured.

Example 6
In a 1 L glass flask, 107 g of oleyl alcohol, 120 g of 1-bromooctane (reagent manufactured by Tokyo Chemical Industry Co., Ltd.), 10 g of tetrabutylammonium bromide (reagent manufactured by Tokyo Chemical Industry Co., Ltd.), 200 g of aqueous sodium hydroxide solution (60 g of sodium hydroxide) Was dissolved in 140 g of water) and stirred at 70 ° C. for 20 hours for reaction. After completion of the reaction, the reaction mixture was transferred to a separatory funnel, and the organic phase was washed 5 times with 300 mL of water, and then the organic phase was distilled to obtain 103 g of n-octyl oleyl ether. Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of this compound were measured.

Example 7
158 g of butoxyethyl oleate was obtained in the same manner as in Example 1 except that 65 g of ethylene glycol monobutyl ether (a reagent manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of 145 g of oleyl alcohol. Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of this compound were measured.

[Comparative Example 1]
The same procedure as in Example 1 was carried out except that 71 g of 2-ethylhexanol (a reagent manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of 145 g of oleyl alcohol to obtain 161 g of 2-ethylhexyl oleate. Various physical properties (thermal conductivity, kinematic viscosity, viscosity index, density, volume resistivity) of this compound were measured.

[Comparative Example 2]
Various physical properties (thermal conductivity, kinematic viscosity, viscosity index, density, volume resistivity) of Group II refined mineral oil (manufactured by Idemitsu Kosan Co., Ltd.) were measured.

[Method of measuring physical properties]
(1) Thermal conductivity Using a thermal characteristic meter KD2pro manufactured by Decagon Co., Ltd., it was measured at room temperature of 25 ° C. with a single needle sensor.

(2) Volume resistivity Measured at room temperature of 25 ° C. according to JIS C 2101 No. 24 (volume resistivity test).
(3) Kinematic viscosity It measured based on the "petroleum product kinematic viscosity test method" prescribed | regulated to JISK2283.
(4) Viscosity index It measured based on the "petroleum product kinematic viscosity test method" prescribed | regulated to JISK2283.
(5) Density The density was measured according to JIS K2249 “Crude oil and petroleum products—Density test method”.
(6) The total number of terminal methyl groups, methylene groups, and ether groups in the main chain, and the total number of methyl branches and ethyl branches in the molecule 6850 type gas chromatograph manufactured by Agilent Technologies and the target product by AL-400 type NMR manufactured by JEOL After confirming the formation of, it was determined from the structural formula.

〔Evaluation results〕
As can be seen from the results in Table 1, the base oils (compounds) of this embodiment shown in Examples 1 to 7 are predetermined esters or ethers, both of which are terminal methyl groups and methylene groups in the main chain. In addition, since the total number of ether groups is 23 or more and the total number of methyl branches and ethyl branches in the molecule is 1 or less, both thermal conductivity (cooling property) and electrical insulation are excellent. Furthermore, since the kinematic viscosity is within a predetermined range, the lubricating performance is excellent. Therefore, the equipment cooling oil using the base oil of this embodiment is a combined oil that also serves as a lubricant for transmissions and the like for cooling motors, batteries, inverters, engines and batteries for electric vehicles and hybrid vehicles. It can be understood that it is also suitable.
On the other hand, Comparative Example 1 is an ester with an alcohol having 8 carbon atoms as in Example 3, but is poor in thermal conductivity because the total number of terminal methyl groups, methylene groups and ether groups in the main chain is small. Moreover, although the comparative example 2 is a case where refined mineral oil is used, since it is a mixture of many types of isomers and the above-mentioned main chain and various parameters in the molecule are not within a predetermined range, it is inferior in thermal conductivity.

Second Embodiment
The base oil in the first embodiment has at least one of oleyl ester (oleic acid ester, oleyl alcohol ester) and oleyl ether as a basic component.
The equipment cooling base oil according to the second embodiment of the present invention contains at least one of an aliphatic monoester and an aliphatic monoether as a basic component.
The total number of terminal methyl groups, methylene groups and ether groups in the main chain in the monoester and the monoether is 18 or more, and the total number of methyl branches and ethyl branches in the monoester molecule and the monoether molecule. Are both 2 or less. Here, the main chain refers to the longest chain structure in the molecule.
The second embodiment of the present invention will be described in detail below.
In the present embodiment, the description of the same contents as those of the first embodiment described above is omitted or simplified.

In this embodiment, an aliphatic monoester and an aliphatic monoether are used as main components of the base oil. Further, from the viewpoint of improving cooling performance, the total number of terminal methyl groups, methylene groups and ether groups in the main chain in the above-mentioned ester or ether is 18 or more. Furthermore, the total number of methyl branches and ethyl branches in the above-described ester or ether molecules is 2 or less from the viewpoint of improving the cooling performance. Further, from the viewpoint of improving cooling performance, the number of methylene groups in the above-mentioned ester or ether is preferably 17 or more. From the viewpoint of cooling properties, the above-described ester or ether is preferably a chain structure, and more preferably a linear structure that does not include a branch.

Such an ester can be obtained by a generally known ester production method, and is not particularly limited. Examples thereof include a dehydration condensation reaction between a carboxylic acid and an alcohol, a condensation reaction between a carboxylic acid halide and an alcohol, or a transesterification reaction. For example, using a raw material with a long linear alkyl chain, the total number of terminal methyl groups, methylene groups, and ether groups in the main chain, which is the longest chain part of the molecule, is 18 or more, and short alkyl side chains (methyl) It is preferable to synthesize by reacting so that the total number of branches and ethyl branches is 2 or less.

Examples of the raw material carboxylic acid include n-hexanoic acid, n-heptanoic acid, n-octanoic acid, n-nonanoic acid, n-decanoic acid, n-undecanoic acid, n-dodecanoic acid, n-tridecanoic acid, n-tetradecanoic acid, oleic acid, and ethylhexane. Examples thereof include monocarboxylic acids such as acid, butyloctanoic acid, pentylnonanoic acid, hexyldecanoic acid, heptylundecanoic acid, octyldodecanoic acid, methylheptadecanoic acid, and benzoic acid. Moreover, as raw materials for ester production, carboxylic acid esters and carboxylic acid chlorides which are derivatives of these carboxylic acids can also be used.

Examples of the starting alcohol include n hexanol, n heptanol, n octanol, n nonanol, n decanol, n undecanol, n dodecanol, n tridecanol, n tetradecanol, oleyl alcohol, ethyl hexanol, butyl octanol, pentyl nonanol, Hexyl decanol, heptyl undecanol, octyl dodecanol, methyl heptadecanol, benzyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, Diethylene glycol monopropyl ether, diethylene glycol Monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, and include monools such as triethylene glycol monobutyl ether.
As the esterification catalyst, a catalyst such as titanium tetraisopropoxide may be used as in the above-described embodiment, or no catalyst may be used.
Moreover, the above-mentioned ether may be produced by a general ether production method such as a usual Williamson ether synthesis method as in the above-described embodiment, and there is no particular limitation.

The base oil of this embodiment contains 30% by mass or more of the above-described ester or ether, but the content as the base oil is preferably 50% by mass or more, more preferably 60% by mass or more, and 70 The content is more preferably at least mass%, particularly preferably at least 80 mass%. If a base oil having an ester or ether content of less than 30% by mass is used, the cooling performance may not be sufficiently exhibited. Of course, you may use the base oil of this embodiment independently (100 mass%) as a base oil for apparatus cooling.

The base oil of this embodiment has a 40 ° C. kinematic viscosity of 4 mm ² / s or more and 30 mm ² / s or less, preferably 4 mm ² / s or more and 20 mm ² / s or less, as in the embodiment described above. When the 40 ° C. kinematic viscosity is less than 4 mm ² / s, for example, when used as a combined oil for a motor and a transmission, the lubricity may be insufficient. On the other hand, if the 40 ° C. kinematic viscosity exceeds 30 mm ² / s, the cooling performance may be insufficient, and there may be a problem in the system circulation as cooling oil for motors and the like.

In the base oil of this embodiment, the thermal conductivity at 25 ° C. is preferably 0.142 W / (m · K) or more in the same manner as in the above-described embodiment, and more preferably 0.144 W. / (M · K) or more.
The base oil of the present embodiment is preferably a volume resistivity at 25 ° C. from the viewpoint of electrical insulation is ^{10 10} Omega · cm or more, more preferably ^{10 11} Omega · cm or more, ^{10 12} More preferably, it is Ω · cm or more, and particularly preferably 10 ¹³ Ω · cm or more.

As the base oil of this embodiment, the same other components (base oils) as described in the first embodiment can be mixed and used in the above-described ester or ether.

The equipment cooling oil composed of the base oil of the present embodiment described above can be suitably used for cooling motors, batteries, inverters, engines, batteries, and the like of electric vehicles and hybrid vehicles as in the above-described embodiments. Further, since the 40 ° C. viscosity of the base oil is also in a predetermined range, it is excellent in lubricity and is preferable as a dual-purpose oil that also lubricates planetary gears, transmissions, and the like.
In addition, the same additive as what was demonstrated in 1st Embodiment can be mix | blended with the equipment cooling oil of this embodiment in the range which does not inhibit the objective of this invention.

<Example of the second embodiment>
Next, the second embodiment will be described in more detail by way of examples. However, the present embodiment is not limited to these examples.
Specifically, each base oil as shown in Table 2 was prepared and subjected to various evaluations. The method for preparing the base oil is as follows.
In addition, about evaluation, it performed by the method similar to the physical-property measuring method in the Example of 1st Embodiment.

[Example 1]
In a 500 mL four-necked flask equipped with a Dean-Stark apparatus, 128 g of 16-methylheptadecanoic acid (trade name: isostearic acid EX manufactured by Higher Alcohol Industry Co., Ltd.) and 101 g of 1-dodecyl alcohol (reagent manufactured by Tokyo Chemical Industry Co., Ltd.) 100 ml of mixed xylene (reagent manufactured by Tokyo Chemical Industry Co., Ltd.) and 0.1 g of titanium tetraisopropoxide (reagent manufactured by Tokyo Chemical Industry Co., Ltd.) are added, and the reaction is carried out at 140 ° C. for 2 hours while distilling off water while stirring with a nitrogen stream. I let you. Thereafter, washing with a saturated saline solution and washing with a 0.1 N aqueous sodium hydroxide solution were performed three times each, followed by drying over anhydrous magnesium sulfate (a reagent manufactured by Tokyo Chemical Industry Co., Ltd.). After filtering the magnesium sulfate, excess raw material alcohol was distilled off to obtain 182 g of n-dodecyl 16-methylheptadecanoate. Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of this compound were measured. The results are shown in Table 2. The results are similarly shown in Table 2 for the following examples and comparative examples.

[Example 2]
180 g of 2-heptylundecanoic acid n-dodecyl was obtained in the same manner as in Example 1 except that 128 g of 2-heptylundecanoic acid (reagent manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of 128 g of 16-methylheptadecanoic acid. . Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of this compound were measured.

Example 3
16-methylheptadecanoic acid was prepared in the same manner as in Example 1 except that 134 g of 16-methylheptadecyl alcohol (trade name: Isostearyl Alcohol EX manufactured by Higher Alcohol Industry Co., Ltd.) was used instead of 101 g of 1-dodecyl alcohol. 206 g of 16-methylheptadecyl was obtained. Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of this compound were measured.

Example 4
Other than using 128 g of 16-methylheptadecanoic acid, 78 g of n-decanoic acid (a reagent manufactured by Tokyo Chemical Industry Co., Ltd.) instead of 101 g of 1-dodecyl alcohol, and 86 g of 1-decyl alcohol (a reagent manufactured by Tokyo Chemical Industry Co., Ltd.) Was carried out in the same manner as in Example 1 to obtain 132 g of n-decyl n-decanoate. Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of this compound were measured.

Example 5
128 g of 16-methylheptadecanoic acid, 72 g of n-octanoic acid (a reagent manufactured by Tokyo Chemical Industry Co., Ltd.) instead of 101 g of 1-dodecyl alcohol, and 119 g of 2-octyldodecanol (New Nippon Rika Co., Ltd., trade name: NJECOAL 200A) Except that was used, the same procedure as in Example 1 was performed to obtain 132 g of 2-octyldodecyl n-octanoate. Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of this compound were measured.

Example 6
To a 2 L glass flask, 300 g of 2-octyldodecanol (Shin Nippon Chemical Co., Ltd., trade name: NJECOAL 200A), 300 g of 1-bromooctane (reagent manufactured by Tokyo Chemical Industry Co., Ltd.), tetrabutylammonium bromide (Tokyo Chemical Industry Co., Ltd.) (Reagent) 30 g and sodium hydroxide aqueous solution 500 g (150 g of sodium hydroxide dissolved in 350 g of water) were added and stirred at 50 ° C. for 20 hours for reaction. After completion of the reaction, the reaction mixture was transferred to a separatory funnel, and the organic phase was washed 5 times with 500 mL of water, and then the organic phase was distilled to obtain 266 g of 2-octyldodecyl n octyl ether. Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of this compound were measured.

Example 7
128 g of 16-methylheptadecanoic acid, 144 g of n-octanoic acid (a reagent manufactured by Tokyo Chemical Industry Co., Ltd.) and 165 g of triethylene glycol monobutyl ether (a reagent manufactured by Tokyo Chemical Industry Co., Ltd.) were used instead of 101 g of 1-dodecyl alcohol. Was performed in the same manner as in Example 1 to obtain 188 g of n-octanoic acid ester of triethylene glycol monobutyl ether. Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of this compound were measured.

[Comparative Example 1]
128 g of 16-methylheptadecanoic acid, 79 g of 3,5,5-trimethylhexanoic acid (a reagent manufactured by Tokyo Chemical Industry Co., Ltd.) instead of 101 g of 1-dodecyl alcohol, and 2-octyldodecanol (Shin Nippon Rika Co., Ltd.) Name: Engecol 200A) 139 g of 2-octyldodecyl 3,5,5-trimethylhexanoate was obtained in the same manner as in Example 1 except that 119 g was used. Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of this compound were measured.

[Comparative Example 2]
128 g of 16-methylheptadecanoic acid, 114 g of 2,2,4,8,10,10-hexamethyl-5-undecanoic acid (a reagent manufactured by Tokyo Chemical Industry Co., Ltd.) instead of 101 g of 1-dodecyl alcohol, and 3,5 2,2,4,8,10,10-hexamethyl-5-undecanoic acid 3,5, except that 72 g of 1,5-trimethylhexanol (reagent manufactured by Tokyo Chemical Industry Co., Ltd.) was used. , 148 g of 5-trimethylhexyl was obtained. Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of this compound were measured.

[Comparative Example 3]
Various properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of 1-decanol (reagent manufactured by Tokyo Chemical Industry Co., Ltd.) were measured.

[Comparative Example 4]
Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of Group II refined mineral oil (Idemitsu Kosan Co., Ltd.) were measured.

〔Evaluation results〕
As can be seen from the results in Table 2, the base oils (compounds) of this embodiment shown in Examples 1 to 7 all have a total number of terminal methyl groups, methylene groups and ether groups in the main chain of 18 or more. In addition, since the total number of methyl branches and ethyl branches in the molecule is 2 or less, both thermal conductivity (cooling property) and electrical insulation are excellent. Furthermore, since the kinematic viscosity is within a predetermined range, the lubricating performance is excellent. Therefore, the equipment cooling oil using the base oil of this embodiment is a combined oil that also serves as a lubricant for transmissions and the like for cooling motors, batteries, inverters, engines and batteries for electric vehicles and hybrid vehicles. It can be understood that it is also suitable.
On the other hand, Comparative Example 1 is the same ester of 2-octyldodecanol as Example 5, but is inferior in thermal conductivity because of many methyl branches. Since the ester of Comparative Example 2 has very many methyl branches, the thermal conductivity is extremely poor. Since Comparative Example 3 is an alcohol, its thermal conductivity is good, but its electrical insulation is poor. Although the comparative example 4 is a case where refined mineral oil is used, since it is a mixture of many kinds of isomers and the above-mentioned main chain and various parameters in the molecule are not within a predetermined range, it is inferior in thermal conductivity.

<Third Embodiment>
The base oil in the first embodiment includes at least one of oleyl ester (oleic acid ester, oleyl alcohol ester) and oleyl ether as a basic component, and the base oil in the second embodiment includes an aliphatic monoester and a fat. At least one of the group monoethers was used as a basic component.
The base oil for equipment cooling according to the third embodiment of the present invention contains at least one of aliphatic dihydric carboxylic acid diester, aliphatic dihydric alcohol diester, and aliphatic dihydric alcohol diether as a basic component.
The total number of terminal methyl groups, methylene groups and ether groups in the main chain in the aliphatic diester and aliphatic diether is 20 or more, and the total number of methyl branches and ethyl branches in the aliphatic diester and aliphatic diether is 2 It is as follows. Here, the main chain refers to the longest chain structure in the molecule.
The third embodiment of the present invention will be described in detail below.
In the present embodiment, the description of the same contents as those of the first embodiment and the second embodiment described above will be omitted or simplified.

In this embodiment, the total number of terminal methyl groups, methylene groups and ether groups in the main chain is 20 or more, and the total number of methyl branches and ethyl branches in the molecule is 2 or less. At least one of them is used as the main component of the base oil. Further, from the viewpoint of improving the cooling performance, the number of methylene groups in the above-mentioned diester or diether is preferably 18 or more, and more preferably 19 or more.
Furthermore, the above-mentioned diesters and diethers are preferably linear from the viewpoint of improving the cooling performance as a base oil.

Such an aliphatic diester can be obtained by a generally known ester production method, and is not particularly limited. For example, a dehydration condensation reaction between a divalent carboxylic acid and an alcohol, a dehydration condensation reaction between a dihydric alcohol and a carboxylic acid, a condensation reaction between a divalent carboxylic acid dihalide and an alcohol, or a dihydric alcohol and a carboxylic acid halide. A condensation reaction, a transesterification reaction, etc. are mentioned. For example, using a raw material with a long linear alkyl chain, the total number of terminal methyl groups, methylene groups and ether groups in the main chain, which is the longest chain part of the molecule, is 20 or more, and short alkyl side chains (methyl) It is preferable to synthesize by reacting so that the total number of branches and ethyl branches is 2 or less.

Examples of the carboxylic acid as a raw material include dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, and 1,10-decamethylene dicarboxylic acid, n-butanoic acid, n-pentanoic acid, n-hexanoic acid, n-heptanoic acid, and n-octanoic acid. , N-nonanoic acid, n-decanoic acid, n-undecanoic acid, n-dodecanoic acid, n-tridecanoic acid, n-tetradecanoic acid, ethylhexanoic acid, butyloctanoic acid and the like. Moreover, as raw materials for ester production, carboxylic acid esters and carboxylic acid chlorides which are derivatives of these carboxylic acids can also be used.

Examples of the starting alcohol include n hexanol, n heptanol, n octanol, n nonanol, n decanol, n undecanol, n dodecanol, n tridecanol, n tetradecanol, oleyl alcohol, ethyl hexanol, butyl octanol, pentyl nonanol, Monols such as hexyl decanol, heptyl undecanol, octyl dodecanol, and methyl heptadecanol, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexane Examples include diols such as diol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, and polytetramethylene glycol.
As the esterification catalyst, a catalyst such as titanium tetraisopropoxide may be used as in the above-described embodiment, or no catalyst may be used.
Further, the above-mentioned diether may be produced by a general ether production method such as an ordinary Williamson ether synthesis method as in the above-described embodiment, and there is no particular limitation.

The base oil of the present embodiment contains 30% by mass or more of the above-mentioned diester or diether, but the content as the base oil is preferably 50% by mass or more, more preferably 60% by mass or more, and 70 The content is more preferably at least mass%, particularly preferably at least 80 mass%. If a base oil having a content of the above diester or diether of less than 30% by mass is used, the cooling performance may not be sufficiently exhibited. Of course, you may use the base oil of this embodiment independently (100 mass%) as a base oil for apparatus cooling.

In the base oil of this embodiment, the thermal conductivity at 25 ° C. is preferably 0.142 W / (m · K) or more in the same manner as in the above-described embodiment, and more preferably 0.144 W. / (M · K) or more.
The base oil of the present embodiment is preferably a volume resistivity at 25 ° C. from the viewpoint of electrical insulation is ^{10 10} Omega · cm or more, more preferably ^{10 11} Omega · cm or more, ^{10 12} More preferably, it is Ω · cm or more.

<Example of the third embodiment>
Next, the third embodiment will be described in more detail by way of examples. However, the present embodiment is not limited to these examples.
Specifically, various base oils as shown in Table 3 were prepared and subjected to various evaluations. The method for preparing the base oil is as follows.
In addition, about evaluation, it performed by the method similar to the physical-property measuring method in the Example of 1st Embodiment.

[Example 1]
In a 500 mL four-necked flask equipped with a Dean-Stark apparatus, 94 g of azelaic acid (reagent manufactured by Tokyo Chemical Industry Co., Ltd.), 156 g of 1-octanol (reagent manufactured by Tokyo Chemical Industry Co., Ltd.), 100 mL of mixed xylene (reagent manufactured by Tokyo Chemical Industry Co., Ltd.) ), 0.1 g of titanium tetraisopropoxide (reagent manufactured by Tokyo Chemical Industry Co., Ltd.) was added, and the mixture was reacted at 140 ° C. for 2 hours while distilling off water under stirring with a nitrogen stream. Thereafter, washing with a saturated saline solution and washing with a 0.1 N aqueous sodium hydroxide solution were performed three times each, followed by drying over anhydrous magnesium sulfate (a reagent manufactured by Tokyo Chemical Industry Co., Ltd.). After filtering the magnesium sulfate, excess raw material alcohol was distilled off to obtain 188 g of di-n-octyl azelate. Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of this compound were measured. The results are shown in Table 3. The results are also shown in Table 3 for the following examples and comparative examples.

[Example 2]
Example except that 94 g of azelaic acid and 75 g of azelaic acid, 53 g of 1-octanol (reagent manufactured by Tokyo Chemical Industry Co., Ltd.) and 65 g of 2-ethylhexanol (reagent manufactured by Tokyo Chemical Industry Co., Ltd.) were used instead of 94 g of azelaic acid and 156 g of 1-octanol. In the same manner as in Example 1, 145 g of a mixture composed of 30% by mass of di-n-octyl azelate, 45% by mass of n-octyl 2-ethylhexyl azelate, and 25% by mass of di-2-ethylhexyl azelate was obtained. Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of this mixture were measured.

Example 3
Various properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of dodecanedioic acid di-2-ethylhexyl (a reagent manufactured by Tokyo Chemical Industry Co., Ltd.) were measured.

Example 4
Example except that 94 g of azelaic acid and 81 g of sebacic acid, 53 g of 1-octanol (reagent manufactured by Tokyo Chemical Industry Co., Ltd.) and 65 g of 2-ethylhexanol (reagent manufactured by Tokyo Chemical Industry Co., Ltd.) were used instead of 94 g of azelaic acid and 156 g of 1-octanol. In the same manner as in Example 1, 147 g of a mixture of 32% by mass of di-n-octyl sebacate, 46% by mass of n-octyl 2-ethylhexyl sebacate and 22% by mass of di-ethylhexyl sebacate was obtained. Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of this mixture were measured.

Example 5
In a 1 L glass flask, 27 g of 1,4-butanediol (reagent manufactured by Tokyo Chemical Industry Co., Ltd.), 174 g of 1-bromooctane (reagent manufactured by Tokyo Chemical Industry Co., Ltd.), tetrabutylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) (Reagent) 10 g and 200 g of aqueous sodium hydroxide solution (60 g of sodium hydroxide dissolved in 140 g of water) were added and stirred at 70 ° C. for 20 hours for reaction. After completion of the reaction, the reaction mixture was transferred to a separatory funnel, and the organic phase was washed 5 times with 300 mL of water, and then excess 1-bromooctane was distilled off to obtain 76 g of bis-n-octyl 1,4-butanediether. . Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of this compound were measured.

Example 6
Example 1 except that 94 g of azelaic acid and 130 g of 2-ethylhexanoic acid (a reagent manufactured by Tokyo Chemical Industry Co., Ltd.) and 75 g of polytetrahydrofuran 250 (a reagent manufactured by Sigma-Aldrich) were used instead of 94 g of azelaic acid and 156 g of 1-octanol. And 126 g of 2-ethylhexanoic acid diester of polytetrahydrofuran 250 was obtained. Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of this ester were measured.

Example 7
The same procedure as in Example 1 was conducted, except that 94 g of azelaic acid and 180 g of n-octanoic acid (reagent manufactured by Tokyo Chemical Industry Co., Ltd.) and 75 g of triethylene glycol (reagent manufactured by Tokyo Chemical Industry Co., Ltd.) were used instead of 94 g of azelaic acid and 156 g of 1-octanol. As a result, 163 g of n-octanoic acid diester of triethylene glycol was obtained. Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of this ester were measured.

[Comparative Example 1]
Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of azelaic acid di-2-ethylhexyl (a reagent manufactured by Tokyo Chemical Industry Co., Ltd.) were measured.

[Comparative Example 2]
In the same manner as in Example 1 except that 94 g of azelaic acid and 173 g of n-octanoic acid (a reagent manufactured by Tokyo Chemical Industry Co., Ltd.) and 52 g of neopentyl glycol (a reagent manufactured by Tokyo Chemical Industry Co., Ltd.) were used instead of 94 g of 1-octanol. To obtain 160 g of neopentyl glycol n-octanoic acid diester. Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of this compound were measured.

[Comparative Example 3]
Example 1 except that 94 g of azelaic acid and 165 g of 2-ethylhexanoic acid (a reagent manufactured by Tokyo Chemical Industry Co., Ltd.) and 52 g of neopentyl glycol (a reagent manufactured by Tokyo Chemical Industry Co., Ltd.) were used instead of 156 g of azelaic acid In the same manner, 160 g of neopentyl glycol 2-ethylhexanoic acid diester was obtained. Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of this compound were measured.

[Comparative Example 4]
Various properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of group II refined mineral oil (manufactured by Idemitsu Kosan Co., Ltd.) were measured.

〔Evaluation results〕
As can be seen from the results in Table 3, the base oil (compound) of the present embodiment shown in Examples 1 to 7 is a predetermined ester or ether, both of which are terminal methyl groups and methylene groups in the main chain. In addition, since the total number of ether groups is 20 or more and the total number of methyl branches and ethyl branches in the molecule is 2 or less, both thermal conductivity (cooling property) and electrical insulation are excellent. Furthermore, since the kinematic viscosity is within a predetermined range, the lubricating performance is excellent. Therefore, the equipment cooling oil using the base oil of the present embodiment is also used for cooling motors, batteries, inverters, engines and batteries for electric vehicles and hybrid vehicles, and also for lubrication of transmissions, etc. It can be understood that the oil is also suitable.
On the other hand, the esters of Comparative Examples 1 and 2 are inferior in thermal conductivity because the main chain is short and the number of methylene groups is small. In addition, the ester of Comparative Example 3 has a short main chain and a small number of methylene groups, and is very inferior in thermal conductivity because of many methyl branches and ethyl branches. Although the comparative example 4 is a case where refined mineral oil is used, since it is a mixture of many kinds of isomers and the above-mentioned main chain and various parameters in the molecule are not within a predetermined range, it is inferior in thermal conductivity.

<Fourth embodiment>
The base oil in the first embodiment includes at least one of oleyl ester (oleic acid ester, oleyl alcohol ester) and oleyl ether as a basic component, and the base oil in the second embodiment includes an aliphatic monoester and a fat. The base oil according to the third embodiment includes at least one of the aliphatic monoethers as a basic component, and the base oil in the third embodiment is at least one of aliphatic dihydric carboxylic acid diesters, aliphatic dihydric alcohol diesters, and aliphatic dihydric alcohol diethers. Any one of them was used as a basic component.
The equipment cooling base oil according to the fourth embodiment of the present invention includes an aliphatic triester, an aliphatic triether, an aliphatic tri (ether ester), an aliphatic tetraester, an aliphatic tetraether, and an aliphatic tetra (ether ester). At least one of aromatic diester, aromatic diether, and aromatic di (ether ester) is used as the main component of the base oil.
In addition, the total number of terminal methyl groups, methylene groups and ether groups in the main chain in each of the above ester molecules, each ether molecule, and each ether ester molecule is 18 or more, and methyl in each of the above ester molecules and each ether molecule. The total number of branches and ethyl branches is 1 or less. Here, the main chain refers to the longest chain structure portion in a molecule that may pass through an aromatic ring. In addition, aliphatic tri (ether ester) refers to a compound having a total of three ether groups and ester groups, and aliphatic tetra (ether ester) refers to a compound having a total of four ether groups and ester groups, Aromatic di (ether ester) refers to a compound having a total of two ether groups and ester groups.
The fourth embodiment of the present invention will be described in detail below.
In the present embodiment, the description of the same contents as those of the first to third embodiments described above is omitted or simplified.

As described in the first embodiment, esters and ethers having a long chain structure are advantageous in order to improve thermal conductivity by liquid molecules and to increase the collision frequency between molecules. In addition, since the aromatic ring is very rigid and does not diffuse molecular vibration energy so much, even if long chain structures are connected via the aromatic ring, the thermal conductivity is not lowered so much. Therefore, in this embodiment, in the case of an aromatic compound, the longest chain structure via an aromatic ring is the main chain.

Therefore, in this embodiment, aliphatic triester, aliphatic triether, aliphatic tri (ether ester), aliphatic tetraester, aliphatic tetraether, aliphatic tetra (ether ester), aromatic diester, aromatic diether And at least any one compound of aromatic di (ether ester) is used as the main component of the base oil. Further, from the viewpoint of improving the cooling performance, the total number of terminal methyl groups, methylene groups and ether groups in the main chain in each of the above-mentioned esters, ethers and ether esters is 18 or more. Further, the total number of methyl branches and ethyl branches in the molecule of each ester, each ether and each ether ester is 1 or less from the viewpoint of improving the cooling performance. Moreover, it is preferable that neither the above-mentioned methyl branch and ethyl branch have from a viewpoint of a cooling improvement.

Such an ester can be obtained by a generally known ester production method, and is not particularly limited. Examples thereof include a dehydration condensation reaction between a carboxylic acid and an alcohol, a condensation reaction between a carboxylic acid halide and an alcohol, or a transesterification reaction. For example, using a raw material with a long linear alkyl chain, the total number of terminal methyl groups, methylene groups, and ether groups in the main chain, which is the longest chain part of the molecule, is 18 or more, and short alkyl side chains (methyl) It may be synthesized by reacting so that the total number of branches and ethyl branches is 1 or less.

Examples of the raw material carboxylic acid include aliphatic carboxylic acids and aromatic carboxylic acids. For example, n hexanoic acid, n heptanoic acid, n octanoic acid, n nonanoic acid, n decanoic acid, n undecanoic acid, n dodecanoic acid, n tridecanoic acid, n tetradecanoic acid, oleic acid, ethyl hexanoic acid, butyl octanoic acid, pentyl nonane Acids, hexyldecanoic acid, heptylundecanoic acid, octyldodecanoic acid, methylheptadecanoic acid, salicylic acid, 4-hydroxybenzoic acid, benzoic acid, phenylacetic acid and other monocarboxylic acids and phthalic acid, isophthalic acid, terephthalic acid and other dicarboxylic acids Etc. Moreover, as raw materials for ester production, carboxylic acid esters and carboxylic acid chlorides which are derivatives of these carboxylic acids can also be used.

Examples of the starting alcohol include n hexanol, n heptanol, n octanol, n nonanol, n decanol, n undecanol, n dodecanol, n tridecanol, n tetradecanol, oleyl alcohol, ethyl hexanol, butyl octanol, pentyl nonanol, Hexyl decanol, heptyl undecanol, octyl dodecanol, methyl heptadecanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether Ether, diethylene glycol monobutyl ether Monools such as triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, and triethylene glycol monobutyl ether, triols such as trimethylolpropane and trimethylolethane, tetraols such as pentaerythritol Is mentioned.
As the esterification catalyst, a catalyst such as titanium tetraisopropoxide may be used as in the above-described embodiment, or no catalyst may be used.
Moreover, the above-mentioned ether may be produced by a general ether production method such as a usual Williamson ether synthesis method as in the above-described embodiment, and there is no particular limitation.

The base oil of the present embodiment contains 30% by mass or more of the above-mentioned ester or ether, but the content as the base oil is preferably 50% by mass or more, more preferably 60% by mass or more. % Or more is more preferable, and 80% by mass or more is particularly preferable. If a base oil having an ester or ether content of less than 30% by mass is used, the cooling performance may not be sufficiently exhibited. Of course, you may use the base oil of this embodiment independently (100 mass%) as a base oil for apparatus cooling.

<Example of the fourth embodiment>
Next, the fourth embodiment will be described in more detail by way of examples. However, the present embodiment is not limited to these examples.
Specifically, various base oils as shown in Table 4 were prepared and subjected to various evaluations. The method for preparing the base oil is as follows.
In addition, about evaluation, it performed by the method similar to the physical-property measuring method in the Example of 1st Embodiment.

[Example 1]
In a four-necked flask equipped with a 500 ML Dean-Stark apparatus, 173 g of n-octanoic acid (reagent manufactured by Tokyo Chemical Industry Co., Ltd.), 34 g of pentaerythritol (reagent manufactured by Tokyo Chemical Industry Co., Ltd.), 100 ml of mixed xylene (manufactured by Tokyo Chemical Industry Co., Ltd.) Reagent) and 0.1 g of titanium tetraisopropoxide (reagent manufactured by Tokyo Chemical Industry Co., Ltd.) were added and reacted at 140 ° C. for 2 hours while distilling off water while stirring under a nitrogen stream. Thereafter, washing with a saturated saline solution and washing with a 0.1 N aqueous sodium hydroxide solution were performed three times each, followed by drying over anhydrous magnesium sulfate (a reagent manufactured by Tokyo Chemical Industry Co., Ltd.). After filtering the magnesium sulfate, excess raw material alcohol was distilled off to obtain 148 g of pentaerythritol tetra-n-octanoic acid ester. Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of this compound were measured. The results are shown in Table 4. The results are also shown in Table 4 for the following examples and comparative examples.

[Example 2]
Trimethylolpropane tri-n was prepared in the same manner as in Example 1 except that 173 g of n-octanoic acid, 159 g of n-octanoic acid instead of 34 g of pentaerythritol, and 40 g of trimethylolpropane (reagent manufactured by Tokyo Chemical Industry Co., Ltd.) were used. 139 g of octanoic acid ester was obtained. Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of this compound were measured.

Example 3
Example 1 except that 173 g of n-octanoic acid, 44 g of phthalic anhydride (a reagent manufactured by Tokyo Chemical Industry Co., Ltd.) and 149 g of 1-dodecanol (a reagent manufactured by Tokyo Chemical Industry Co., Ltd.) were used instead of 34 g of pentaerythritol To obtain 137 g of di-n-decyl phthalate. Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of this compound were measured.

Example 4
Example 1 except that 173 g of n-octanoic acid and 50 g of isophthalic acid (reagent manufactured by Tokyo Chemical Industry Co., Ltd.) and 104 g of 1-octanol (reagent manufactured by Tokyo Chemical Industry Co., Ltd.) were used instead of 34 g of pentaerythritol. To obtain 107 g of di-n-octyl isophthalate. Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of this compound were measured.

Example 5
In a 1 L glass flask, 34 g of trimethylolpropane (reagent manufactured by Tokyo Chemical Industry Co., Ltd.), 217 g of 1-bromooctane (reagent manufactured by Tokyo Chemical Industry Co., Ltd.), 10 g of tetrabutylammonium bromide (reagent manufactured by Tokyo Chemical Industry Co., Ltd.) 200 g of an aqueous sodium hydroxide solution (60 g of sodium hydroxide dissolved in 140 g of water) was added, and the mixture was stirred at 70 ° C. for 20 hours for reaction. After completion of the reaction, the reaction mixture was transferred to a separatory funnel, and the organic phase was washed 5 times with 300 mL of water, and then excess 1-bromooctane was distilled off and n-octanoic acid (reagent manufactured by Tokyo Chemical Industry Co., Ltd.) 50 g, 100 ml of mixed xylene (reagent made by Tokyo Chemical Industry Co., Ltd.), 0.1 g of titanium tetraisopropoxide (reagent made by Tokyo Chemical Industry Co., Ltd.) are put into a 500 mL four-necked flask equipped with a Dean-Stark device, and stirred with a nitrogen stream. The reaction was carried out at 140 ° C. for 2 hours while distilling off water to esterify the unreacted alcohol portion of trimethylolpropane. After washing with a saturated saline solution, excess n-octanoic acid was distilled off, and a 0.1 N aqueous sodium hydroxide solution was washed three times, followed by drying over anhydrous magnesium sulfate (a reagent manufactured by Tokyo Chemical Industry Co., Ltd.). After filtering the magnesium sulfate, the solvent was distilled off to obtain 24% of n-octyl triether of trimethylolpropane, n-octyl diether of trimethylolpropane, 58% of octanoic acid monoester, n-octyl monoether of trimethylolpropane. 102 g of a mixture of 18% octanoic acid diester was obtained. Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of this compound were measured.

[Comparative Example 1]
Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of trimethylolpropane 2-ethylhexanoic acid triester (a reagent manufactured by Tokyo Chemical Industry Co., Ltd.) were measured.

[Comparative Example 2]
Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of di-2-ethylhexyl phthalate (reagent manufactured by Tokyo Chemical Industry Co., Ltd.) were measured.

[Comparative Example 3]
Various physical properties (thermal conductivity, volume resistivity, kinematic viscosity, viscosity index, density) of Group II refined mineral oil (manufactured by Idemitsu Kosan Co., Ltd.) were measured.

〔Evaluation results〕
As can be seen from the results in Table 4, all of the base oils (compounds) of the present embodiment shown in Examples 1 to 5 have a total number of terminal methyl groups and methylene groups in the main chain of 18 or more. Since the total number of methyl branches and ethyl branches is 1 or less, both thermal conductivity (coolability) and electrical insulation are excellent. Furthermore, since the kinematic viscosity is within a predetermined range, the lubricating performance is excellent. Therefore, the equipment cooling oil using the base oil of this embodiment is a combined oil that also serves as a lubricant for transmissions and the like for cooling motors, batteries, inverters, engines and batteries for electric vehicles and hybrid vehicles. It can be understood that it is also suitable.
On the other hand, Comparative Example 1 is the same trimethylolpropane triester as in Example 2. However, since the main chain is short and there are many ethyl branches, the thermal conductivity is poor. Comparative Example 2 is the same phthalic acid ester as Example 3, but is inferior in thermal conductivity because the main chain is short and there are many ethyl branches. Although the comparative example 3 is a case where refined mineral oil is used, since it is a mixture of many types of isomers and the above-mentioned main chain and various parameters in the molecule are not within a predetermined range, it is inferior in thermal conductivity.

The present invention can be used for equipment cooling base oil, equipment cooling oil blended with the base oil, equipment cooled by the cooling oil, and equipment cooling method using the cooling oil.

Claims

A base oil for equipment cooling containing 30% by mass or more of at least one of oleyl ester (oleic acid ester, oleyl alcohol ester) and oleyl ether,
The oleyl ester and the oleyl ether have a total number of terminal methyl groups, methylene groups and ether groups in the main chain of 23 or more,
The total number of methyl and ethyl branches in the oleyl ester and the oleyl ether is 1 or less,
The base oil for equipment cooling, wherein the base oil has a kinematic viscosity at 40 ° C. of 4 mm 2 / s or more and 30 mm 2 / s or less.
In the base oil for equipment cooling according to claim 1,
A base oil for equipment cooling, comprising 50% by mass or more of the oleyl ester and the oleyl ether.
A base oil for equipment cooling containing 30% by mass or more of at least one of an aliphatic monoester and an aliphatic monoether,
The total number of terminal methyl groups, methylene groups and ether groups in the main chain of the aliphatic monoester and the aliphatic monoether is 18 or more;
The total number of methyl and ethyl branches in the aliphatic monoester and the aliphatic monoether is 2 or less;
The base oil for equipment cooling, wherein the base oil has a kinematic viscosity at 40 ° C. of 4 mm 2 / s to 30 mm 2 / s.
In the equipment cooling base oil according to claim 3,
A base oil for equipment cooling, wherein at least one of the aliphatic monoester and the aliphatic monoether has a chain structure.
A base oil for equipment cooling containing 30% by mass or more of at least one of an aliphatic diester and an aliphatic diether,
The total number of terminal methyl groups, methylene groups and ether groups in the main chain of the aliphatic diester and the aliphatic diether is 20 or more;
The total number of methyl and ethyl branches in the aliphatic diester and the aliphatic diether is 2 or less;
The base oil for equipment cooling, wherein the base oil has a kinematic viscosity at 40 ° C. of 4 mm 2 / s or more and 30 mm 2 / s or less.
Aliphatic triester, aliphatic triether, aliphatic tri (ether ester), aliphatic tetraester, aliphatic tetraether, aliphatic tetra (ether ester), aromatic diester, aromatic diether, and aromatic di (ether) A base oil for equipment cooling containing 30% by mass or more of at least one of ester),
The total number of terminal methyl groups, methylene groups, and ether groups in the main chain of each ester, each ether, and each ether ester is 18 or more, and methyl branching in each ester, each ether, and each ether ester And the total number of ethyl branches is 1 or less,
The base oil for equipment cooling, wherein the base oil has a kinematic viscosity at 40 ° C. of 4 mm 2 / s or more and 30 mm 2 / s or less.
In the base oil for apparatus cooling of any one of Claim 1- Claim 6,
A base oil for equipment cooling having a thermal conductivity at 25 ° C of 0.142 W / (m · K) or more.
In the base oil for apparatus cooling of any one of Claim 1- Claim 7,
The volume resistivity at 25 ° C. is 10 10 Ω · cm or more.
It consists of base oil for apparatus cooling of any one of Claim 1- Claim 8. The apparatus cooling oil characterized by the above-mentioned.
The apparatus is cooled by the apparatus cooling oil according to claim 9.
The device according to claim 10 is for an electric vehicle or a hybrid vehicle.
The device according to claim 10 or 11, wherein the device is at least one of a motor, a battery, an inverter, an engine, and a battery.
The equipment cooling oil according to claim 9 is used. The equipment cooling method characterized by things.