Coolant composition

Abstract

To provide a cooling liquid composition which can maintain insulation properties even when water is mixed, and which has high work efficiency when replacing the cooling liquid by reducing odor.SOLUTION: A cooling liquid composition of the present disclosure contains mineral oil and / or synthetic oil, and boric acid ester. A conductivity of the cooling liquid composition is less than 0.1 μS / cm.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to coolant compositions. [Background technology]

[0002] Patent Document 1 discloses a non-aqueous coolant composition having excellent insulating and heat transfer properties, which contains at least one carboxylic acid ester compound and is substantially free of water. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-31597 Summary of the Invention [Problem to be solved by the invention]

[0004] When a coolant composition is used to cool, for example, a battery of an electric vehicle, the coolant composition must be replaced. Therefore, a coolant composition that is easy to use is desired. Furthermore, water may be mixed into the coolant composition due to condensation or the like, which may result in a decrease in insulating properties. For example, insulating properties are required to a degree that can prevent the coolant from coming into contact with the battery terminals and causing a short circuit when the coolant leaks due to an accident involving an electric vehicle or the like.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a coolant composition that can maintain insulating properties even when water is mixed in, reduces odor, and improves workability when replacing the coolant. [Means for solving the problem]

[0006] In order to solve the above problems and achieve the above objects, the following coolant composition is provided. The coolant composition according to the present disclosure contains a mineral oil and / or a synthetic oil and a borate ester, and the conductivity of the coolant composition is less than 0.1 μS / cm.

[0007] According to the coolant composition of the present disclosure, by adding a borate ester to oil, even if water is mixed in, the borate ester (B(OR)3: R is each independently an organic group) is hydrolyzed to ROH and HOB(OR)2 or (HO)2B(OR). As a result, water is absorbed and insulation properties are maintained. Furthermore, because borate esters do not have a molecular structure that causes odor, odor can be significantly reduced. As a result, the workability when replacing the coolant composition can be significantly improved.

[0008] In the above disclosure, the boric acid ester is preferably represented by the general formula B(OR)3, where R is each independently an organic group having an alkyl group and / or an aromatic ring, and the total number of carbon atoms of the three R is preferably 18 to 54.

[0009] This can improve the dispersibility of the borate ester in mineral oils and / or synthetic oils. [Effects of the Invention]

[0010] The coolant composition according to the present disclosure has the excellent effect of being able to provide a coolant composition that can maintain insulating properties even when water is mixed in, and that has reduced odor and improves workability when replacing the coolant. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present disclosure will be described in detail below. It goes without saying that other embodiments are also included in the scope of the present disclosure as long as they conform to the spirit of the present disclosure.

[0012] The coolant composition according to the embodiment is applied to coolants for batteries, inverters, oil coolers, radiators, and the like provided in electric vehicles, for example, and has excellent insulating properties.

[0013] The coolant composition according to the embodiment contains a mineral oil and / or a synthetic oil and a borate ester. The conductivity of the coolant composition according to the embodiment is less than 0.1 μS / cm. The borate ester is preferably a compound represented by the following formula: Formula: B(OR)3 In the formula, each R is independently an organic group. R is preferably a hydrocarbon group, but may contain heteroatoms such as oxygen atoms and nitrogen atoms. Examples of hydrocarbon groups include chain (including linear and branched) or alicyclic aliphatic groups, aromatic groups, and groups formed by any combination thereof. R may have a substituent. Examples of the substituent include a hydroxyl group, an amino group, a carboxyl group, and a halogen atom. As described above, the three R in the above formula may be different, but are preferably the same.

[0014] Specific examples of borate esters include trimethyl borate, triethyl borate, tripropyl borate, triisopropyl borate, tributyl borate, triisobutyl borate, tripentyl borate, trihexyl borate, trioctyl borate, triisooctyl borate, trinonyl borate, tridecyl borate, tridodecyl borate, trihexadecyl borate, trioctadecyl borate, triphenyl borate, and tricyclyl borate. hexyl, tribenzyl borate, triethanolamine borate, tris-o-phenylene bisborate, bis-o-phenylene pyroborate, bis-2,3-dimethylethylenephenylene pyroborate, bis-2,2-dimethyltrimethylene pyroborate, tris(2-ethylhexyloxy)borane, bis(1,4,7,10-tetraoxaundecyl)(1,4,7,10,13-pentaoxatetradecyl)( 1,4,7-trioxaundecyl)borane, 2-(β-dimethylaminoisopropoxy)-4,5-dimethyl-1,3,2-dioxaborolane, 2-(β-diethylaminoethoxy)-4,4,6-trimethyl-1,3,2-dioxaborinane, 2-(β-dimethylaminoethoxy)-4,4,6-trimethyl-1,3,2-dioxaborinane, 2-(β-diisopropylaminoethoxy)-1,3,2-dioxaborinane borinane, 2-(β-diisopropylaminoethoxy)-4-methyl-1,3,2-dioxaborinane, 2-(γ-dimethylaminopropoxy)-1,3,6,9-tetrapyrrolidone-2-boracycloundecane, and 2-(β-dimethylaminoethoxy)-4,4-(4-hydroxybutyl)-1,3,2-dioxaborinane, 2,2-oxybis(5,5-dimethyl-1,3,2-dioxabonaline).

[0015] From the viewpoint of improving the dispersibility of the boric acid ester in mineral oils and / or synthetic oils, it is preferable that each R in the general formula B(OR)3 is independently an organic group having an alkyl group and / or an aromatic ring. It is also preferable that the total number of carbon atoms of the three R is 18 to 54. It is more preferable that each R is an alkyl group having 6 to 18 carbon atoms and / or a group having an aromatic ring.

[0016] The coolant composition according to the embodiment can trap water by hydrolysis of the borate ester contained therein, even if water is mixed in due to condensation or the like during use in an electric vehicle. This allows the desired insulating properties to be maintained. The desired insulating properties are those that can prevent the coolant from coming into contact with the battery terminals and causing a short circuit, for example, in the event of a coolant leak due to an electric vehicle accident. The coolant composition according to the embodiment can achieve the desired insulating properties by having an electrical conductivity of less than 0.1 μS / cm. It is more preferable that the electrical conductivity of the coolant composition be less than 0.0009 μS / cm.

[0017] The coolant composition according to the embodiment may contain other additives in addition to the borate ester, such as antioxidants, rust inhibitors, viscosity index improvers, pour point lowering agents, dispersants, surfactants, anti-wear additives, antifoaming agents, and flow antistatic agents.

[0018] When the coolant composition according to the embodiment is used by forced convection using a pump or the like, the viscosity of the coolant composition is 10 mm at 40°C. 2 In this case, the viscosity of the coolant composition may be adjusted by, for example, lowering the viscosity of the mineral oil to be contained or by adjusting the content by mass % of the mineral oil to be contained.

[0019] The cooling system includes, for example, a refrigerant pipe through which the coolant composition flows, a reserve tank for storing the coolant composition, a circulation device for circulating the coolant composition within a circulation path, or a cooling device for lowering the temperature of the coolant composition. Examples of the circulation device include an electric pump. Examples of the cooling device include a radiator, a chiller, or an oil cooler. The cooling system is intended to cool heat-generating devices such as inverters, converters, generators, motors, or batteries.

[0020] The configuration of the cooling system is not particularly limited. The cooling system may include, for example, a refrigerant pipe, a reserve tank, an electric pump, a radiator, and a cooling unit provided in the heat-generating equipment. The cooling unit is a part that receives heat from the heat-generating equipment. For example, the coolant composition is pumped from the reserve tank by the electric pump, cools the heat-generating equipment in the cooling unit, and then returns to the reserve tank via the downstream radiator. After cooling the cooling unit, the temperature of the coolant composition rises, so the temperature of the coolant composition is lowered by the radiator. Alternatively, an oil cooler may be placed midway in the refrigerant pipe, and the motor may be cooled by this oil cooler. [Example]

[0021] The present embodiment will be described in more detail below using examples.

[0022] <Raw materials> Tributyl borate (boric acid ester) Trihexyl borate (boric acid ester) Trioctyl borate (boric acid ester) Tritetradecyl borate (boric acid ester) Trioctadecyl borate (boric acid ester) Ethyl n-octanoate Mineral oil: kinematic viscosity (20°C) 0.1 to 10 mm 2 / s LLC concentrate (Toyota genuine product, product name: Super Long Life Coolant, contains ethylene glycol and additives) Ethylene glycol (Tokyo Chemical Industry Co., Ltd.) Ion-exchanged water

[0023] Example 1 A coolant composition according to Example 1 was prepared by mixing 90 mass % of mineral oil and 10 mass % of trihexyl borate as a base oil.

[0024] (Examples 2 to 4, Comparative Examples 1 to 5) The coolant compositions according to each example were prepared in the same manner as in Example 1, except that the compositions and contents were changed as shown in Table 1.

[0025] (conductivity) The conductivity of each coolant composition was measured by adjusting the temperature of each coolant composition to 20°C using a conductivity measuring device (manufactured by Yokogawa Electric Corporation, personal SC meter SC72, ​​detector: SC72SN-11).

[0026] (Check whether water remains) To each coolant composition, 0.3% by mass of water was added, and the mixture was heated and stirred for 15 minutes at 50° C. Thereafter, the presence or absence of water droplets was visually confirmed to determine whether or not water remained.

[0027] (cooling property) Using each example of the coolant composition as a refrigerant, the cooling performance of the radiator was calculated using the following formula. The results are shown in Table 1. The refrigerant was adjusted so that its inlet temperature was 65°C. Other conditions were as follows: airflow rate to the radiator: 4.5 m / sec, refrigerant flow rate: 10 L / min, temperature difference between the refrigerant and the outside air: 40°C (coolant: 65°C, outside air: 25°C).

number

[0028] (Odor Intensity) The odor of each coolant composition was evaluated according to the following criteria in accordance with the Offensive Odor Prevention Law. 0: Odorless. 1: Detection threshold concentration (smell that can just be detected). 2: Recognition threshold concentration (weak odor that allows you to identify what the odor is). 3: An easily detectable smell. 4: Strong smell. 5: Strong smell.

[0029] [Table 1]

[0030] The coolant compositions of all Examples had electrical conductivity of less than 0.0009 μS / cm, demonstrating excellent insulating properties. The cooling performance of the radiators using the coolant compositions of all Examples was 190 W / K or higher, demonstrating sufficient cooling performance for practical use. It was also confirmed that no water droplets were observed in any of the coolant compositions of the Examples. The odor level was also confirmed to be 2, which is within the perceptible threshold concentration. On the other hand, the coolant compositions of Comparative Examples 1 to 3 had electrical conductivities of 7000 μS / cm, 0.6 μS / cm, and 0.3 μS / cm, respectively, demonstrating insufficient insulating properties. The coolant compositions of Comparative Examples 4 and 5 had electrical conductivities of less than 0.0009 μS / cm, demonstrating excellent insulating properties. However, in Comparative Example 4, water droplets were visually observed in the above-mentioned test, and in Comparative Example 5, the odor level was 4, demonstrating workability issues when replacing the coolant.

[0031] The above results demonstrate that the coolant compositions according to this embodiment (the coolant compositions of Examples 1 to 4) have excellent insulating properties, and can maintain their insulating properties even when water gets mixed in due to condensation or the like when used in an electric vehicle, and can also reduce odors.

Claims

[Claim 1] mineral oil and / or synthetic oil; and a boric acid ester, The conductivity is less than 0.1 μS / cm; The boric acid ester is represented by the general formula B(OR) 3 , The coolant composition has three R's each independently representing an alkyl group and / or an organic group having an aromatic ring, and the total number of carbon atoms of the three R's is 18 to 54.

Images