Hydrofluoroether composition

Abstract

Provided is a hydrofluoroether composition suppressed in flow electrification and excellent in stability even at a high temperature of 150°C. A hydrofluoroether composition according to the present invention contains 1,1,1,2,3,3-hexafluoro-3-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]propane and water, and has a water content of 5-600 ppm by mass.

Description

Hydrofluoroether composition

[0001] The present invention relates to a hydrofluoroether (HFE) composition useful as a heat transfer medium or the like.

[0002] Hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs) are non-flammable, have low toxicity, and are stable, and are therefore used as cleaning agents, solvents, foaming agents, aerosols, and heat transfer media for heat pipes and binary power generation using factory waste heat.

[0003] However, since HFCs and PFCs have a large global warming potential (GWP) and a large impact on the environment due to the greenhouse effect, there is a demand for the development of fluorine-containing compounds that have a smaller impact on the environment. As a fluorine-containing compound to replace HFCs and PFCs, for example, the use of HFEs such as 1,1,1,2,3,3-hexafluoro-3-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]propane (hereinafter abbreviated as HFE-77-12) as a heat transfer medium or the like is being considered (see, for example, Patent Document 1).

[0004] Special Publication No. 2007-524737

[0005] Fluorine-containing compounds have higher electrical insulation properties and tend to accumulate static electricity (become charged) more easily than compounds that do not contain fluorine atoms, such as hydrocarbon compounds. Charged fluorine-containing compounds may pose a risk of ignition due to sudden discharge. In particular, when fluorine-containing compounds are used as heat transfer media, a phenomenon known as flow electrification is likely to occur, in which fluorine-containing compounds flowing on the surface of non-conductive materials become statically charged. Charged heat transfer media may adversely affect the materials that make up the flow path of the heat transfer media due to partial discharge.

[0006] For this reason, it is preferable that fluorine-containing compounds do not generate flow electrification in industrial applications, particularly in the field of electronics. Furthermore, in order to stably use fluorine-containing compounds not only as heat transfer media but also in various applications such as cleaning agents, solvents, foaming agents, aerosols, etc., fluorine-containing compounds with excellent high-temperature stability (for example, stable use even in an environment of 150°C) are required.

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an HFE composition that suppresses flow electrification and has excellent stability even at temperatures as high as 150°C.

[0008] The present invention is based on the discovery that an HFE composition containing a predetermined small amount of water is less likely to cause flow electrification and remains stable even at a high temperature of 150°C.

[0009] The present invention provides the following means. [1] A hydrofluoroether composition comprising 1,1,1,2,3,3-hexafluoro-3-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]propane and water, wherein the water content is 5 to 600 ppm by mass. [2] The hydrofluoroether composition of [1], wherein the content of 1,1,1,2,3,3-hexafluoro-3-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]propane is 50% by mass or more. [3] A heat transfer medium which is the hydrofluoroether composition of [1] or [2]. [4] The heat transfer medium of [3], which is used for cooling or heating components in semiconductor manufacturing equipment.

[0010] According to the present invention, there is provided an HFE composition that suppresses flow electrification and has excellent stability even at a high temperature of 150° C. Therefore, the HFE composition of the present invention can be used stably and continuously as a heat transfer medium.

[0011] FIG. 1 is a schematic diagram of a flow electrification test device used in the examples.

[0012] The HFE composition according to an embodiment of the present invention (hereinafter also referred to as the present embodiment) contains 1,1,1,2,3,3-hexafluoro-3-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]propane (hereinafter abbreviated as HFE-77-12) and water, and has a water content of 5 to 600 ppm by mass.

[0013] HFE-77-12 has the chemical formula CF ３ CHFCF ２ OCH ２ CH ２ OCF ２ CHFCF ３HFE-77-12 has a high boiling point of 164°C, but a freezing point below -100°C, and is liquid over a wide temperature range, making it an excellent heat transfer medium.

[0014] HFE-77-12 has a GWP of approximately 100 to 500 (estimated value), which is lower than that of HFCs and PFCs. The GWP of the HFE composition of this embodiment is preferably 1,000 or less, more preferably 500 or less. Note that GWP is an estimated value obtained by integrating the intensity of the greenhouse effect (radiant energy given to the Earth) per concentration when a target substance is released into the atmosphere over 100 years, with carbon dioxide as the standard. The GWP (estimated value) of HFE-77-12 and the HFE composition can be determined based on their chemical structures from the GWP values ​​of known fluorine-based heat transfer media.

[0015] The water content in the HFE composition of the present embodiment is 5 to 600 ppm by mass, preferably 5 to 500 ppm by mass, and more preferably 10 to 100 ppm by mass, from the viewpoints of suppressing flow electrification and stability at a high temperature of 150°C.

[0016] By having a water content of 5 ppm by mass or more, flow electrification of the HFE composition is sufficiently suppressed. Furthermore, by having a water content of 600 ppm by mass or less, acid generation is suppressed even at a high temperature of 150°C, and the stability of the HFE composition is likely to be maintained. Therefore, when the HFE composition of this embodiment is used as a heat transfer medium, it can suppress corrosion of metal members and the like of a heat transfer medium circulating device due to acids derived from the HFE. Furthermore, since flow electrification is suppressed, adverse effects of partial discharge and the like on the flow path of the heat transfer medium are suppressed, and the HFE composition is particularly suitable for use as a heat transfer medium in the electronics field.

[0017] The content of HFE-77-12 in the HFE composition of this embodiment is preferably 30% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, still more preferably 70% by mass or more, and most preferably 80% by mass or more. When the HFE composition of this embodiment is used as a heat transfer medium, from the viewpoint of enabling HFE-77-12 itself to exhibit good properties as a heat transfer medium, the content of HFE-77-12 is preferably more than 98.0000% by mass and 99.9999% by mass or less, more preferably 99.0000% by mass or more and 99.9998% by mass or less, and even more preferably 99.9000% by mass or more and 99.9995% by mass or less.

[0018] When the HFE composition of the present embodiment is used as a heat transfer medium, from the viewpoint of stably exhibiting the properties of HFE-77-12 as a heat transfer medium, the total content of HFE-77-12 and water is preferably 99.0000% by mass or more, more preferably 99.5000% by mass or more, and particularly preferably 100% by mass.

[0019] The HFE composition of the present embodiment may consist only of HFE-77-12 and water, or may contain components other than HFE-77-12 and water (for example, fluorine-based solvents, stabilizers, impurities derived from the production method of HFE-77-12, etc.) for various purposes such as improving various properties, within a range that does not impair the effects of the present invention.

[0020] When the HFE composition contains a fluorine-based solvent, the content is preferably less than 70% by mass, more preferably less than 50% by mass, even more preferably less than 30% by mass, and even more preferably less than 20% by mass. Examples of the fluorine-based solvent include Galden (registered trademark) HT90 / 110 / 135 / 150 / 200 (all CF ３ - [OCF (CF ３ ) (CF ２ ) ｎ (OCF ２ ) ｍ ]-CF ３), ZV90, SVX, ZT-180; FTM-110 / 135 / 150 / 170 / 200 / 230 / 270 manufactured by Sanming Hexafluo Chemicals; Fluorinert (registered trademark) FC-75 (C ８ F ８ ) / 3283 ((C ３ F ７ ) ３ N) / 40 ((C ４ F ９ ) ３ N) / 43 ((C ４ F ９ ) ３ N) / 70 ((C ５ F １１ ) ３ N), FX-3300(C ８ F ８ ), Novec 7100 (CF ３ (CF ２ ) ３ OCH ３ and (CF ３ ) ２ CFCF ２ OCH ３ Mixture of CF ３ (CF ２ ) ３ O.C. ２ H ５ and (CF ３ ) ２ CFCF ２ O.C. ２ H ５ Mixture of CF ３ ) ２ CFCF (CF ２ CF ３ ) OCH ３ ) / 7500 (CF ３ CF ２ CF ２ CF (OCH ２ CH ３ )CF(CF ３ )CF ３ ) / 7600 (CF ３ CFHCF ２ OC (CH ３ )CF ２ CFHCF ３ ); Opteon (registered trademark) SF10 / 30 (CF３ CH=CHCF ３ and CClH = CClH mixture) / 33(CF ３ CH=CHCF ３ ) / 2P50; Asahiklin (registered trademark) AC-2000 (CF ３ CF ２ CF ２ CF ２ CF ２ CF ２ H) / 6000(CF ３ CF ２ CF ２ CF ２ CF ２ CF ２ CH ２ CH ３ ), Amorea (registered trademark) AS-300 (CF ２ Examples of commercially available products include HCl (HCF=CClH).

[0021] When the HFE composition contains a stabilizer, the content is preferably less than 5 mass%, more preferably less than 3 mass%, and even more preferably less than 1 mass%. Examples of the stabilizer include phenol compounds, unsaturated hydrocarbon group-containing aromatic compounds, aromatic amine compounds, aromatic thiazine compounds, terpene compounds, quinone compounds, nitro compounds, epoxy compounds, and orthoester compounds.

[0022] When the HFE composition contains impurities derived from the production method of HFE-77-12, the content thereof is preferably less than 1 mass%, more preferably less than 1000 mass ppm, even more preferably less than 500 mass ppm, and still more preferably less than 100 mass ppm. Examples of impurities derived from the production method of HFE-77-12 include 1,2,3,3,3-pentafluoro-1-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]-1-propene.

[0023] The HFE composition of this embodiment is obtained by mixing HFE-77-12 and water. The method for producing HFE-77-12 is not particularly limited. HFE-77-12 can be synthesized by a known method, such as an addition reaction of hexafluoropropene with ethylene glycol in the presence of an alkali catalyst such as potassium carbonate. Specifically, HFE-77-12 can be produced by the method described in the following examples.

[0024] Because the HFE composition of this embodiment has a small GWP, it can be suitably used in a wide range of applications, including as a cleaning agent, solvent, foaming agent, aerosol, heat transfer medium for heat pipes and binary power generation using factory waste heat, storage liquid for electronic components, and medium for gross leak tests, thermal shock tests, liquid burn-in tests, and voltage resistance tests for electronic components. Furthermore, as described above, since the composition can suppress acid generation and maintain stability even at temperatures as high as 150°C, it can be suitably used as a heat transfer medium. Examples of heat transfer mediums include those used for wafer temperature control in semiconductor manufacturing, cooling and heating of semiconductor elements and electronic components, cooling of servers, heat pumps, heat pipes, and thermostatic baths. The HFE composition of this embodiment is suitable as a heat transfer medium for cooling or heating components in semiconductor manufacturing equipment, and is also suitable as a heat transfer medium used continuously under harsh conditions of high electric fields and high temperatures, such as in dry etching processes using thermal plasma in semiconductor manufacturing.

[0025] The present invention will be specifically described below based on examples, but the present invention is not limited to the following examples. The reaction product was identified by proton nuclear magnetic resonance ( １ H NMR) spectrum, fluorine-19 nuclear magnetic resonance ( １９ F NMR) spectrum and gas chromatography mass spectrometry (GC-MS (column used: "DB-1301", length 60 m, inner diameter 250 μm, thickness 1 μm; manufactured by Agilent Technologies, Inc.)).

[0026] [Synthesis of HFE-77-12] 223 g of potassium carbonate (manufactured by Junsei Chemical Co., Ltd.), 200 g of ethylene glycol (manufactured by Junsei Chemical Co., Ltd.), and 400 g of anhydrous acetonitrile (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were placed in a stainless steel autoclave (internal volume 2.1 liters) equipped with a stirrer, and the mixture was kept sealed at 20 ° C. The contents of the autoclave were stirred, and 966 g of hexafluoropropene (manufactured by AGC Inc.) was added in a gaseous state over 6 hours. After maintaining the mixture at 20 ° C. for 1 hour to allow the reaction, the reaction crude liquid in the autoclave was recovered by filtration. The recovered reaction crude liquid contained 45% by mass of HFE-77-12. Next, 1000 g of the reaction crude liquid was placed in a Hastelloy (registered trademark) autoclave (internal volume 2.1 liters), and 100 g of anhydrous hydrogen fluoride (manufactured by AGC Inc.) was added and stirred for 1 hour. The resulting crude reaction liquid was phase-separated, washed with water, dried over molecular sieve 3A (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and then purified by distillation to obtain HFE-77-12.

[0027] [Examples 1 to 6] Preparation of HFE compositions Ion-exchanged water was added to the HFE-77-12 synthesized above to prepare HFE compositions containing the amount of water shown in each example in Table 1. Examples 2 to 5 are working examples, and Examples 1 and 6 are comparative examples. The water content in the HFE compositions was measured using a Karl Fischer moisture meter ("CA-100", manufactured by Nitto Seiko Analytech Co., Ltd.).

[0028] [Evaluation of Physical Properties] The following physical properties were evaluated for each of the HFE compositions of Examples 1 to 6. The evaluation results are shown in Table 1.

[0029] (Evaluation of Flow Electrification) Flow electrification was evaluated using a test apparatus as shown in FIG. 1 , using an HFE composition as a heat transfer medium. The test apparatus shown in FIG. 1 comprises a heat transfer medium reservoir 1, a pump 3 for circulating the heat transfer medium through a pipe 2, a metal rod 4 (made of SUS316), and an electrometer (not shown). A soft polyvinyl chloride hose ("Toyolon (registered trademark) TR-4", manufactured by Toyox Corporation; inner diameter 4 mm, length 15 cm) was used as the pipe 2. A digital electrostatic potential meter ("KSD-2000", manufactured by Kasuga Electric Co., Ltd.) was used as the electrometer. The heat transfer medium was circulated through the pipe 2 at a flow rate of 5.5 L / min in an atmosphere at room temperature (25°C), and the potential difference between the metal rod 4 and the heat transfer medium was measured after 10 minutes.

[0030] When a heat transfer medium is continuously circulated through a non-conductive pipe, flow electrification occurs, and the amount of charge tends to increase. The smaller the negative value of the potential difference (the larger the absolute value), the greater the amount of negative charge on the heat transfer medium. For example, when used as a heat transfer medium in a dry etching device in semiconductor manufacturing, according to the above evaluation method, a suitable standard for the potential difference is −0.5 kV or more, more preferably −0.45 kV or more, and even more preferably −0.41 kV or more.

[0031] (High-Temperature Stability Test) 100 g of the HFE composition was placed in a polytetrafluoroethylene (PTFE) container containing a test piece (25 mm x 30 mm, 2 mm thick) of general-purpose cold-rolled steel plate (SPCC), and the test piece was immersed and stored at 150°C for 7 days. After the test, the appearance of the test piece was visually observed, and the high-temperature stability of the HFE composition (presence or absence of acid generation) was evaluated according to the following evaluation criteria. <Evaluation Criteria> A: No change B: Loss of surface gloss C: Rust on the surface In the cases of ratings A and B, no rust was observed on the test piece, but in the cases of ratings B and C, it is presumed that the HFE composition generated acid at high temperatures.

[0032]

[0033] From the results shown in Table 1, it was found that when the water content in the HFE composition was 5 to 600 ppm by mass (Examples 2 to 5), the potential difference was −0.50 kV or more, flow electrification was suppressed, and the high-temperature stability was excellent.

[0034] 1 Liquid reservoir 2 Pipe 3 Pump 4 Metal rod

Claims

1. A hydrofluoroether composition comprising 1,1,1,2,3,3-hexafluoro-3-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]propane and water, wherein the water content is 5 to 600 ppm by mass.

2. The hydrofluoroether composition according to claim 1, wherein the content of 1,1,1,2,3,3-hexafluoro-3-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]propane is 50 mass% or more.

3. A heat transfer medium which is the hydrofluoroether composition according to claim 1 or 2.

4. The heat transfer medium according to claim 3, which is used to cool or heat components in semiconductor manufacturing equipment.

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