Refrigerant compositions, refrigeration methods, refrigerators, and use of refrigerant compositions

Abstract

This disclosure provides a refrigerant composition that includes a novel refrigerant and exhibits excellent stability. [Solution] The refrigerant composition of the present disclosure is a composition containing a refrigerant, wherein the refrigerant contains trans-1,2-difluoroethylene and difluoromethane in total at a rate of 99.5% by mass or more relative to the total refrigerant, and the refrigerant contains trans-1,2-difluoroethylene in a rate of 11.2% by mass or more and 19.5% by mass or less relative to the total mass of trans-1,2-difluoroethylene and difluoromethane.

Description

Technical Field

[0001] The present disclosure relates to a refrigerant composition, a refrigeration method, a refrigerating machine, and use of the refrigerant composition.

Background Art

[0002] As a working medium for thermal cycle that can replace R410A, a working medium for thermal cycle containing trifluoroethylene (HFO-1123) and 1,2-difluoroethylene (HFO-1132) has been proposed (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of Invention

Problem to be Solved by the Invention

[0004] An object of the present disclosure is to provide a refrigerant composition containing a novel refrigerant and having excellent stability.

Means for Solving the Problem

[0005] The present disclosure includes the configurations described in the following items. Item 1 A composition comprising a refrigerant, wherein the refrigerant contains, trans-1,2-difluoroethylene and difluoromethane in a total amount of 99.5 mass% or more based on the entire refrigerant, wherein the refrigerant contains, 11.2 mass% or more and 19.5 mass% or less of trans-1,2-difluoroethylene based on the total mass of trans-1,2-difluoroethylene and difluoromethane, the refrigerant composition. Item 2 A composition comprising a refrigerant, wherein the refrigerant contains, It contains trans-1,2-difluoroethylene and difluoromethane in total at a rate of 99.5% by mass or more of the total refrigerant. The aforementioned refrigerant is (i), (ii), and (iii) below (i) The total mass of trans-1,2-difluoroethylene and difluoromethane is 33.4% or more and 37.5% or less of trans-1,2-difluoroethylene; (ii) The total mass of trans-1,2-difluoroethylene and difluoromethane is 40.8% or more and 49.5% or less of trans-1,2-difluoroethylene; (iii) The total mass of trans-1,2-difluoroethylene and difluoromethane is 52.0% or more and 58.2% or less of trans-1,2-difluoroethylene; A refrigerant composition that satisfies at least one of the following conditions. Section 3 A composition containing a refrigerant, The aforementioned refrigerant is It contains trans-1,2-difluoroethylene and difluoromethane in total at a rate of 99.5% by mass or more of the total refrigerant. The aforementioned refrigerant is The total mass of trans-1,2-difluoroethylene and difluoromethane is such that trans-1,2-difluoroethylene is present in an amount of 11.2% or more by mass and 60.0% or less by mass. The refrigerant contains 0.1% by mass or less of water relative to its total mass. A refrigerant composition in which the oxygen content is 0.35 mol% or less relative to the total amount of the refrigerant. Section 4 Among the aforementioned refrigerants, The total content of compounds selected from the group consisting of methylamine, acetylene, HFO-1141, HFO-1123, HFC-143a, HFC-134a, HFO-1132a, Z-HFO-1132, HFO-1243zf, HFC-245cb, HCFC-1122, HCFC-124, CFC-1113, and 3,3,3-trifluoropropyne is 0.5% by mass or less of the total mass of the refrigerant. A refrigerant composition as described in any one of items 1 to 3. Section 5 The refrigerant contains 0.1% by mass or less of water relative to its total mass. The refrigerant composition according to item 1 or 2, wherein the oxygen content is 0.35 mol% or less relative to the total amount of the refrigerant. Item 5´ Among the aforementioned refrigerants, The total content of compounds selected from the group consisting of methylamine, acetylene, HFO-1141, HFO-1123, HFC-143a, HFC-134a, HFO-1132a, Z-HFO-1132, HFO-1243zf, HFC-245cb, HCFC-1122, HCFC-124, CFC-1113, and 3,3,3-trifluoropropyne is 0.5% by mass or less of the total mass of the refrigerant. The refrigerant composition described in item 4. Section 6 A refrigerant composition according to any one of items 1 to 5 and 5', used as a substitute refrigerant for R32, R410A, or R404A. Section 7 A refrigeration method comprising the step of operating a refrigeration cycle using a refrigerant composition described in any one of items 1 to 5 and 5'. Section 8 A refrigerator comprising a refrigerant composition as described in any one of items 1 to 5 and 5' as a working fluid. Section 9 Use of any one of the refrigerant compositions described in items 1 to 5 and 5' as a working fluid in a refrigerator. [Effects of the Invention]

[0006] The refrigerant composition of this disclosure includes a novel refrigerant and exhibits excellent stability. [Modes for carrying out the invention]

[0007] The present inventors conducted extensive research to improve the stability of trans-1,2-difluoroethylene (HFO-1132(E)), and as a result, found that the above objective can be achieved by allowing a predetermined amount of difluoromethane (R32) to coexist therewith.

[0008] Hereinafter, embodiments included in the present disclosure will be described in detail. In the present specification, the expressions "contain" and "comprise" are intended to include the concepts of "contain", "comprise", "consist essentially of", and "consist only of".

[0009] In the numerical ranges described stepwise in the present specification, the upper limit or lower limit of a numerical range at one step can be arbitrarily combined with the upper limit or lower limit of a numerical range at another step. In the numerical ranges described in the present specification, the upper limit or lower limit of the numerical range may be replaced with a value shown in the Examples or a value that can be uniquely derived from the Examples. Further, in the present specification, numerical values connected by "~" mean a numerical range including the numerical values before and after "~" as the lower limit value and the upper limit value.

[0010] <Definition of Terms> In the present specification, the term "refrigerant" at least includes compounds assigned with refrigerant numbers (ASHRAE numbers) starting with R that represent refrigerant types, as defined by ISO817 (International Organization for Standardization), and further includes those that have equivalent characteristics as refrigerants even if they have not yet been assigned a refrigerant number. Refrigerants are roughly classified into "fluorocarbon-based compounds" and "non-fluorocarbon-based compounds" in terms of the structure of the compounds. "Fluorocarbon-based compounds" include chlorofluorocarbons (CFC), hydrochlorofluorocarbons (HCFC), and hydrofluorocarbons (HFC).

[0011] In the present specification, the term "composition containing a refrigerant" includes (1) the refrigerant itself (including mixtures of refrigerants), and (2) a composition that further contains other components and can be used to obtain a working fluid for refrigerators by being mixed with at least a refrigerator oil. (3) Working fluid for refrigerators containing refrigerant oil and This includes at least the following. In this specification, among these three embodiments, the compositions of (1) and (2) will be referred to as "composition containing a refrigerant" or "refrigerant composition." The working fluid for the refrigeration unit of (3) may also be referred to as "working fluid containing refrigeration oil."

[0012] In this specification, when the term “substitute” is used in the context of “substituting” a first refrigerant with a second refrigerant, the first type means that equipment designed to operate using the first refrigerant can be operated under optimal conditions using the second refrigerant with only minor changes to components (at least one of the following: refrigerant oil, gaskets, packings, expansion valves, dryers, and other components) and equipment adjustments as needed. In other words, this type refers to operating the same equipment with a “substitute” refrigerant. The forms of “substitution” in this type may be, in order of increasing degree of change or adjustment required when replacing with the second refrigerant, “drop-in substitution,” “nealy drop-in substitution,” and “retrofit.”

[0013] A second type of "substitution" includes using equipment designed to operate with a second refrigerant, but for the same existing applications as the first refrigerant, by installing the second refrigerant. This type refers to providing the same application by "substituting" a refrigerant.

[0014] In this specification, the term "refrigeration unit" refers to any device that removes heat from an object or space to a temperature lower than the surrounding ambient air and maintains that low temperature. In other words, a refrigerator is a conversion device that obtains energy from an external source, performs work, and converts energy in order to transfer heat from a lower temperature to a higher temperature.

[0015] Unless otherwise specified, the pressures described herein are in absolute pressure units.

[0016] In this specification, "non-flammable" means that the Worst case of formulation for flammability (WCF), which is the most flammable composition among the permissible concentrations of refrigerants, is classified as "Class 1" according to the US ANSI / ASHRAE 34-2013 standard.

[0017] In this specification, "slightly flammable" refrigerant means that its WCF composition is classified as "Class 2L" according to the US ANSI / ASHRAE 34-2013 standard.

[0018] In this specification, "low-flammability" of a refrigerant means that its WCF composition is classified as "Class 2" according to the US ANSI / ASHRAE 34-2013 standard.

[0019] In this specification, GWP(AR4) refers to a value based on the IPCC (Intergovernmental Panel on Climate Change) Fourth Assessment Report.

[0020] Furthermore, in this specification, when a refrigerant is described as ASHRAE low-flammability (WCF & WCFF low-flammability), it means that the WCF has a combustion rate of 10 cm / s or less, and the worst case of fractionation for flammability (WCFF), identified by performing storage, transport, and use leak tests based on ANSI / ASHRAE 34-2013 using WCF, has a combustion rate of 10 cm / s or less, and is judged to be in the "2L class" flammability category according to the US ANSI / ASHRAE 34-2013 standard.

[0021] 1. Refrigerant composition The refrigerant compositions of this disclosure are compositions comprising a refrigerant, wherein the refrigerant comprises at least trans-1,2-difluoroethylene and difluoromethane. Hereinafter, in accordance with convention, trans-1,2-difluoroethylene will be denoted as "E-HFO-1132" and difluoromethane as "R32".

[0022] In the refrigerant composition of this disclosure, the refrigerant contains E-HFO-1132 and R32 in total at a rate of 99.5% by mass or more relative to the total amount of refrigerant.

[0023] In particular, the refrigerant compositions of this disclosure are broadly classified into the following refrigerant composition 1, refrigerant composition 2a, refrigerant composition 2b, refrigerant composition 2c, and refrigerant composition 3, depending on the proportion of E-HFO-1132 and R32 contained in the refrigerant and the proportion of other components not included therein. • Refrigerant composition 1; The refrigerant is, relative to the total mass of E-HFO-1132 and R32, The E-HFO-1132 content is between 11.2% by mass and 19.5% by mass. • Refrigerant composition 2a; The refrigerant is, relative to the total mass of E-HFO-1132 and R32, E-HFO-1132 is present in amounts of 33.4% by mass or more and 37.5% by mass or less. • Refrigerant composition 2b; The refrigerant is, relative to the total mass of E-HFO-1132 and R32, E-HFO-1132 is present in amounts of 40.8% or more by mass and 49.5% or less by mass. • Refrigerant composition 2c; The refrigerant is, relative to the total mass of E-HFO-1132 and R32, E-HFO-1132 is present in amounts between 52.0% by mass and 58.2% by mass. • Refrigerant composition 3; The refrigerant is, relative to the total mass of E-HFO-1132 and R32, E-HFO-1132 is contained in an amount of 11.2% by mass or more and 60.0% by mass or less, The refrigerant contains 0.1% by mass or less of water relative to its total mass. The oxygen content is 0.35 mol% or less relative to the total amount of the refrigerant.

[0024] As described above, refrigerant composition 1 contains 99.5% by mass or more of E-HFO-1132 and R32 in total relative to the total refrigerant, and E-HFO-1132 is present in an amount of 11.2% by mass or more and 19.5% by mass or less relative to the total mass of E-HFO-1132 and R32. In refrigerant composition 1, if the content ratio of E-HFO-1132 relative to the total mass of E-HFO-1132 and R32 in the refrigerant is less than 11.2% by mass, the GWP will increase, specifically exceeding GWP 600. In refrigerant composition 1, if the content ratio of E-HFO-1132 relative to the total mass of E-HFO-1132 and R32 in the refrigerant is 19.5% by mass or less, the combustion rate of WCFF will be 10 cm / s or less, resulting in ASHRAE low combustion.

[0025] In refrigerant composition 1, the content ratio of E-HFO-1132 to the total mass of E-HFO-1132 and R32 in the refrigerant is preferably 12% by mass or more, more preferably 13% by mass or more, even more preferably 14% by mass or more, even more preferably 15% by mass or more, particularly preferably 16% by mass or more, and also preferably 19% by mass or less, and more preferably 18.5% by mass or less. In these cases, combustion of the refrigerant composition can be suppressed.

[0026] The inclusion of a predetermined amount of R32 in refrigerant composition 1 stabilizes E-HFO-1132 compared to the case where other HFCs are included, and also makes oxidation of E-HFO-1132 less likely to occur. In particular, as described later, when refrigerant composition 1 contains water, the intramolecular double bond of E-HFO-1132 is stabilized by water, and the oxidation of E-HFO-1132 is suppressed, and it is presumed that R32 further enhances these effects.

[0027] As described above, refrigerant composition 2a contains 99.5% by mass or more of E-HFO-1132 and R32 in total relative to the total refrigerant, and E-HFO-1132 is present in amounts of 33.4% by mass or more and 37.5% by mass or less relative to the total mass of E-HFO-1132 and R32. This allows for a low GWP and high refrigeration capacity.

[0028] The presence of a predetermined amount of R32 in the refrigerant composition 2a stabilizes E-HFO-1132 compared to the case where other HFCs are included, and also makes oxidation of E-HFO-1132 less likely to occur. In particular, as described later, when the refrigerant composition 1 contains water, the intramolecular double bond of E-HFO-1132 is stabilized by water, and the oxidation of E-HFO-1132 is suppressed, and it is presumed that R32 further enhances these effects.

[0029] As described above, refrigerant composition 2b contains 99.5% by mass or more of E-HFO-1132 and R32 in total relative to the total refrigerant, and E-HFO-1132 is present in 40.8% by mass or more and 49.5% by mass or less relative to the total mass of E-HFO-1132 and R32. This allows for a low GWP and high refrigeration capacity.

[0030] The presence of a predetermined amount of R32 in the refrigerant composition 2b stabilizes E-HFO-1132 compared to the case where other HFCs are included, and also makes oxidation of E-HFO-1132 less likely to occur. In particular, as described later, when the refrigerant composition 1 contains water, the intramolecular double bond of E-HFO-1132 is stabilized by water, and the oxidation of E-HFO-1132 is suppressed, and it is presumed that R32 further enhances these effects.

[0031] As described above, refrigerant composition 2c contains 99.5% by mass or more of E-HFO-1132 and R32 in total relative to the total refrigerant, and E-HFO-1132 is present in a proportion of 52.0% by mass or more and 58.2% by mass or less relative to the total mass of E-HFO-1132 and R32. This allows for a low GWP and high refrigeration capacity.

[0032] The presence of a predetermined amount of R32 in the refrigerant composition 2c stabilizes E-HFO-1132 compared to the case where other HFCs are included, and also makes oxidation of E-HFO-1132 less likely to occur. In particular, as described later, when the refrigerant composition 1 contains water, the intramolecular double bond of E-HFO-1132 is stabilized by water, and the oxidation of E-HFO-1132 is suppressed, and it is presumed that R32 further enhances these effects.

[0033] As described above, refrigerant composition 3 contains 99.5% by mass or more of E-HFO-1132 and R32 in total relative to the total refrigerant, and E-HFO-1132 is contained in an amount of 11.2% by mass or more and 60.0% by mass or less relative to the total mass of E-HFO-1132 and R32. In refrigerant composition 3, if the content ratio of E-HFO-1132 relative to the total mass of E-HFO-1132 and R32 in the refrigerant falls below 11.2% by mass, the GWP increases, specifically exceeding GWP 600. In refrigerant composition 3, if the content ratio of E-HFO-1132 relative to the total mass of E-HFO-1132 and R32 in the refrigerant exceeds 60.0% by mass, disproportionation reactions of E-HFO-1132 are more likely to occur, potentially leading to explosiveness.

[0034] In refrigerant composition 3, the content ratio of E-HFO-1132 to the total mass of E-HFO-1132 and R32 in the refrigerant is preferably 12% by mass or more, more preferably 15% by mass or more, even more preferably 17% by mass or more, even more preferably 35% by mass or more, even more preferably 56% by mass or less, even more preferably 50% by mass or less, and particularly preferably 45% by mass or less.

[0035] The presence of a predetermined amount of R32 in the refrigerant composition 3 stabilizes E-HFO-1132 compared to the case where other HFCs are included, and also makes oxidation of E-HFO-1132 less likely to occur. In particular, as described later, when the refrigerant composition 1 contains water, the intramolecular double bond of E-HFO-1132 is stabilized by water, and the oxidation of E-HFO-1132 is suppressed, and it is presumed that R32 further enhances these effects.

[0036] Refrigerant composition 3 contains, in addition to the refrigerant, 0.1% by mass or less of water relative to the total mass of the refrigerant. That is, refrigerant composition 3 contains 1000 ppm by mass or less of water relative to the total mass of the refrigerant. This stabilizes the intramolecular double bond of E-HFO-1132, an unsaturated fluorocarbon compound that may be contained in the refrigerant, and also makes oxidation of E-HFO-1132 less likely, thereby improving the stability of the refrigerant composition. Furthermore, when water is contained at 0.1% by mass or less relative to the total mass of the refrigerant, for example, the generation of solid matter in the refrigerant composition is also suppressed.

[0037] In refrigerant composition 3, the water content is preferably 500 ppm by mass or less, more preferably 100 ppm by mass or less, even more preferably 50 ppm by mass or less, and particularly preferably 20 ppm by mass or less, based on the total mass of the refrigerant. Furthermore, in refrigerant composition 3, the water content may be 10 ppm by mass or less, 9 ppm by mass or less, or 5 ppm by mass or less, based on the total mass of the refrigerant.

[0038] In the refrigerant composition 3, the water content is preferably 0.1 ppm by mass or more, more preferably 1 ppm by mass or more, even more preferably 2 ppm by mass or more, even more preferably 3 ppm by mass or more, particularly preferably 4 ppm by mass or more, and most preferably 5 ppm by mass or more, based on the total mass of the refrigerant.

[0039] In this disclosure, the water content can be measured using a commercially available Karl Fischer moisture analyzer, and the detection limit is typically 0.1 ppm by mass. Furthermore, in this disclosure, the total amount of refrigerant can be determined by gas chromatography. Therefore, by using a gas chromatograph and a moisture analyzer in combination, the water content can be measured based on the total mass of the refrigerant.

[0040] In refrigerant composition 3, water may be a liquid, a solid, a gas, or a mixture thereof. As used herein, the water content refers to the total amount of gas (water vapor), liquid (water), and solid (ice).

[0041] The refrigerant composition 3, by containing water, improves the stability of E-HFO-1132, and also makes it less likely for solid matter such as aggregates to form even after long-term storage.

[0042] The refrigerant composition 3 may further contain oxygen, specifically, the oxygen content is 0.35 mol% or less relative to the total amount of the refrigerant (i.e., based on the total number of moles of the refrigerant). The oxygen content in the refrigerant composition 3 refers to the oxygen content present in the liquid phase when the refrigerant composition 3 is sealed in a container.

[0043] In refrigerant composition 3, the oxygen content is more preferably 0.12 mol% or less based on the total number of moles of the refrigerant. Furthermore, in refrigerant composition 3, the oxygen content is more preferably 0.0001 mol% or more, and more preferably 0.001 mol% or more, based on the total number of moles of the refrigerant. If the oxygen content is within this range, the stability of E-HFO-1132 in the composition is improved. From this viewpoint, the lower the oxygen content in refrigerant composition 3, the better. However, as mentioned above, the composition contains water, so even if the amount of oxygen is within the above range, the stability of E-HFO-1132 can be maintained by the action of the water. In other words, the presence of oxygen generally destabilizes unsaturated fluorocarbon compounds such as E-HFO-1132, but in the refrigerant composition of this disclosure, the adverse effects on E-HFO-1132 that oxygen may cause are suppressed by water and R32. Therefore, despite containing oxygen, the refrigerant in refrigerant composition 3 of this disclosure has excellent stability.

[0044] In refrigerant composition 3, the oxygen content can be quantified by measuring the oxygen content in the gas phase using a commercially available gas chromatograph and then converting this measurement to determine the oxygen content in the liquid phase. Typically, the detection limit is less than 0.0001 mol%.

[0045] As described above, the refrigerant compositions of this disclosure include refrigerant composition 1, refrigerant composition 2a, refrigerant composition 2b, refrigerant composition 2c, and refrigerant composition 3. The components that may be optionally included in each composition will be described in detail below. In this specification, refrigerant composition 2a, refrigerant composition 2b, and refrigerant composition 2c will be collectively referred to as "refrigerant composition 2".

[0046] (Refrigerant composition 1 and refrigerant composition 2) Refrigerant composition 1 and refrigerant composition 2, like refrigerant composition 3, may contain water in addition to the refrigerant. Specifically, both refrigerant composition 1 and refrigerant composition 2 may contain 0.1% by mass or less of water relative to the total mass of the refrigerant. That is, both refrigerant composition 1 and refrigerant composition 2 may contain 1000 ppm by mass or less of water relative to the total mass of the refrigerant. This stabilizes the intramolecular double bond of E-HFO-1132, an unsaturated fluorocarbon compound that may be contained in the refrigerant, and also makes oxidation of E-HFO-1132 less likely, thereby improving the stability of the refrigerant composition. Furthermore, when water is contained at 0.1% by mass or less relative to the total mass of the refrigerant, for example, the generation of solid matter in the refrigerant composition is also suppressed.

[0047] In both refrigerant composition 1 and refrigerant composition 2, the water content is preferably 500 ppm by mass or less, more preferably 100 ppm by mass or less, even more preferably 50 ppm by mass or less, and particularly preferably 20 ppm by mass or less, relative to the total mass of the refrigerant. Furthermore, the water content may also be 10 ppm by mass or less, 9 ppm by mass or less, or 5 ppm by mass or less, relative to the total mass of the refrigerant.

[0048] In both refrigerant composition 1 and refrigerant composition 2, the water content is preferably 0.1 ppm by mass or more, more preferably 1 ppm by mass or more, even more preferably 2 ppm by mass or more, even more preferably 3 ppm by mass or more, particularly preferably 4 ppm by mass or more, and most preferably 5 ppm by mass or more, based on the total mass of the refrigerant.

[0049] The inclusion of water in refrigerant composition 1 and refrigerant composition 2 improves the stability of E-HFO-1132, and also reduces the formation of solids such as aggregates even after long-term storage.

[0050] Both refrigerant composition 1 and refrigerant composition 2 may further contain oxygen, specifically, the oxygen content is 0.35 mol% or less relative to the total amount of the refrigerant (i.e., based on the total number of moles of the refrigerant). In both refrigerant composition 1 and refrigerant composition 2, the oxygen content refers to the oxygen content present in the liquid phase when the refrigerant composition is sealed in a container.

[0051] In refrigerant composition 1 and refrigerant composition 2, the oxygen content is more preferably 0.12 mol% or less based on the total number of moles of the refrigerant. Furthermore, in refrigerant composition 1 and refrigerant composition 2, the oxygen content is preferably 0.0001 mol% or more, and more preferably 0.001 mol% or more, based on the total number of moles of the refrigerant. If the oxygen content is within this range, the stability of E-HFO-1132 in the composition is improved. From this viewpoint, the lower the oxygen content in refrigerant composition 1 and refrigerant composition 2, the better. However, as mentioned above, the composition contains water, so even if the amount of oxygen is within the above range, the stability of E-HFO-1132 can be maintained by the action of the water. In other words, the presence of oxygen generally destabilizes unsaturated fluorocarbon compounds such as E-HFO-1132, but in the refrigerant compositions of this disclosure, the adverse effects on E-HFO-1132 that oxygen may cause are suppressed by water and R32. Therefore, in both refrigerant composition 1 and refrigerant composition 2 of this disclosure, the refrigerant has excellent stability despite containing oxygen.

[0052] In refrigerant composition 1 and refrigerant composition 2, the oxygen content can be quantified by measuring the oxygen content in the gas phase using a commercially available gas chromatograph and then converting this measurement to determine the oxygen content in the liquid phase. Typically, the detection limit is less than 0.0001 mol%.

[0053] In refrigerant composition 1 and refrigerant composition 2, water may be in the form of a liquid, a gas, or a mixture thereof. As stated above, the water content refers to the total amount of both gas (water vapor) and liquid (water).

[0054] (Refrigerant composition) In this specification, the term "refrigerant composition" encompasses refrigerant composition 1, refrigerant composition 2, and refrigerant composition 3.

[0055] The refrigerant compositions of this disclosure may include other additional refrigerants, as long as they contain E-HFO-1132 and R32 in total at least 99.5% by mass of the total refrigerant. The type of additional refrigerant is not particularly limited as long as it is a refrigerant other than E-HFO-1132 and R32, and can broadly include known refrigerants, for example.

[0056] Additional refrigerants include at least one compound selected from the group consisting of methylamine, acetylene, HFO-1141, HFO-1123, HFC-143a, HFC-134a, HFO-1132a, Z-HFO-1132, HFO-1243zf, HFC-245cb, HCFC-1122, HCFC-124, CFC-1113, and 3,3,3-trifluoropropyne. The meanings of the abbreviations for these compounds are as follows: HFO-1141: Monofluoroethylene, HFO-1123: Trifluoroethylene, HFC-143a: 1,1,1-trifluoroethane HFC-134a: 1,1,1,2-tetrafluoroethane, HFO-1132a: 1,1-difluoroethylene, Z-HFO-1132: cis-1,2-difluoroethylene, HFO-1243zf: 3,3,3-trifluoropropene HFC-245cb: 1,1,1,2,2-pentafluoropropane HCFC-1122: 2-chloro-1,1-difluoroethylene, HCFC-124: 1-chloro-1,2,2,2-tetrafluoroethane, CFC-1113: Chlorotrifluoroethylene That is the case.

[0057] In particular, in the refrigerant composition of this disclosure, the total content of compounds selected from the group consisting of methylamine, acetylene, HFO-1141, HFO-1123, HFC-143a, HFC-134a, HFO-1132a, Z-HFO-1132, HFO-1243zf, HFC-245cb, HCFC-1122, HCFC-124, CFC-1113, and 3,3,3-trifluoropropyne in the refrigerant can be 0.5% by mass or less with respect to the total mass of the refrigerant.

[0058] Note that Z-HFO-1132 refers to cis-1,2-difluoroethylene.

[0059] The refrigerant composition of the refrigerant composition of the present disclosure preferably contains E-HFO-1132 and R32 in a total amount of 99.75% by mass or more, more preferably 99.9% by mass or more, even more preferably 99.999% by mass or more, and most preferably 99.9999% by mass or more, based on the total amount of refrigerant. The refrigerant composition of the present disclosure may consist substantially of E-HFO-1132 and R32 alone, for example, the refrigerant composition of the present disclosure may consist only of E-HFO-1132 and R32 and unavoidable impurities. The refrigerant composition of the present disclosure may consist only of E-HFO-1132 and R32, except when water and oxygen are included.

[0060] In the refrigerant composition of this disclosure, E-HFO-1132 and R32 contained in the refrigerant can be obtained, for example, by known manufacturing methods, or can be obtained from commercially available products.

[0061] When the refrigerant composition of this disclosure is used as a refrigerant or heat transfer medium, the refrigerant composition may contain a lubricating oil as a component other than the refrigerant. The lubricating oil is not particularly limited, and for example, any known lubricating oil used for refrigerants can be widely used.

[0062] Specific lubricants include one or more selected from the group consisting of polyalkylene glycol, polyol ester, and polyvinyl ether. Examples of polyalkylene glycol (PAG) include "SUNICE P56" manufactured by Nippon Sun Oil Co., Ltd. Examples of polyol ester (POE) include "Ze-GLES RB32" manufactured by JX Nippon Oil & Energy Corporation.

[0063] The lubricating oil may be present in the composition in an amount of 1 to 50% by mass, preferably 10 to 40% by mass, relative to the total amount of refrigerant contained in the composition, but this is not limited to this range as it depends on the specifications of the oil tank of the refrigeration unit. The refrigerant composition of this disclosure does not need to contain lubricating oil.

[0064] The refrigerant compositions of this disclosure may contain other components in addition to the refrigerant, such as tracers (additives added to the refrigerant compositions of this disclosure in a detectable concentration so that any changes to the refrigerant composition can be tracked if it is diluted, contaminated, or otherwise altered), ultraviolet fluorescent dyes, stabilizers, polymerization inhibitors, and the like.

[0065] The refrigerant composition of this disclosure may contain 50% by mass or more of refrigerant, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more. Furthermore, the refrigerant composition of this disclosure may contain 99% by mass or more of refrigerant. The remainder is, for example, water, oxygen, and the aforementioned lubricating oil or additives. Alternatively, the refrigerant composition of this disclosure may consist solely of refrigerant.

[0066] The refrigerant composition disclosed herein can be used in a variety of applications and is suitably used as a heat transfer medium, refrigerant, foaming agent, solvent, cleaning agent, propellant, fire extinguishing agent, etc. By containing the refrigerant composition disclosed herein, the quality of the heat transfer medium, refrigerant, foaming agent, solvent, cleaning agent, propellant, and fire extinguishing agent, etc., is maintained over a long period of time. The heat transfer medium, refrigerant, foaming agent, solvent, cleaning agent, propellant, and fire extinguishing agent, etc., can have the same composition as known materials, except that they contain the refrigerant composition disclosed herein.

[0067] The refrigerant compositions of this disclosure can also be applied to various thermal cycle systems. Examples of thermal cycle systems include room air conditioners, commercial package air conditioners, building package air conditioners, facility package air conditioners, split-type air conditioners in which one or more indoor and outdoor units are connected by refrigerant piping, window air conditioners, portable air conditioners, rooftop or central air conditioners that transport hot or cold air through ducts, car air conditioners, and other types of air conditioners; gas engine heat pumps; air conditioning systems such as train air conditioning systems and automobile air conditioning systems; display cases such as built-in display cases and separate display cases; commercial refrigerators and freezers, ice makers, integrated refrigerators, vending machines, refrigerators for cooling containers or refrigerators for maritime transport, chiller units, turbo refrigerators, and other types of refrigeration equipment; or dedicated heating cycle equipment. Examples of dedicated heating cycle equipment include hot water supply systems, floor heating systems, snow melting systems, and the like.

[0068] The method for preparing the refrigerant composition of this disclosure is not particularly limited. For example, a method for preparing the refrigerant composition of this disclosure can be a method of mixing E-HFO-1132 and R32 in a predetermined mixing ratio. Furthermore, if the refrigerant composition contains water, the method for adjusting the water content is not particularly limited, and for example, (1) a method of adjusting the water content by mixing water and refrigerant, (2) a method of adjusting the water content by maintaining the amount of water, or (3) a method of adjusting the water content by decreasing the amount of water. The method for decreasing the amount of water is not particularly limited, and a wide range of known methods can be employed, for example, a drying method using an adsorbent can be cited.

[0069] To summarize for clarity, the refrigerant composition of this disclosure is as follows: Refrigerant composition 1 contains 99.5% by mass or more of E-HFO-1132 and R32 in total relative to the total refrigerant, and E-HFO-1132 is contained in an amount of 11.2% by mass or more and 19.5% by mass or less relative to the total mass of E-HFO-1132 and R32.

[0070] Refrigerant composition 2 contains 99.5% by mass or more of E-HFO-1132 and R32 in total relative to the total refrigerant, and the following (i), (ii), and (iii) (i) E-HFO-1132 is present in a quantity of 33.4% or more and 37.5% or less of the total mass of E-HFO-1132 and R32; (ii) E-HFO-1132 is present in a quantity of 40.8% or more and 49.5% or less of the total mass of E-HFO-1132 and R32; (iii) E-HFO-1132 is present in a quantity of 52.0% or more and 58.2% or less of the total mass of E-HFO-1132 and R32; At least one of the following conditions is met. If refrigerant composition 2 satisfies (i), refrigerant composition 2 corresponds to refrigerant composition 2a; if refrigerant composition 2 satisfies (ii), refrigerant composition 2 corresponds to refrigerant composition 2b; and if refrigerant composition 2 satisfies (iii), refrigerant composition 2 corresponds to refrigerant composition 2c.

[0071] Refrigerant composition 3 contains 99.5% by mass or more of E-HFO-1132 and R32 in total relative to the total amount of refrigerant, and E-HFO-1132 is contained in an amount of 11.2% by mass or more and 60.0% by mass or less relative to the total mass of E-HFO-1132 and R32, water is contained in an amount of 0.1% by mass or less relative to the total mass of the refrigerant, and the oxygen content is 0.35 mol% or less relative to the total amount of the refrigerant.

[0072] 2. Working fluid containing refrigeration oil The refrigerant composition of this disclosure can be used as a working fluid containing refrigerant oil. This working fluid containing refrigerant oil comprises at least the refrigerant composition of this disclosure and refrigerant oil, and is used as a working fluid in a refrigerator. Specifically, the working fluid containing refrigerant oil of this disclosure is obtained by mixing refrigerant oil used in the compressor of a refrigerator with the refrigerant composition. The working fluid containing refrigerant oil generally contains 10% by mass or more of refrigerant oil. The working fluid containing refrigerant oil generally contains 50% by mass or less of refrigerant oil. The refrigerant oil may be contained alone or in combination of two or more types.

[0073] The refrigeration oil is not particularly limited and can be appropriately selected from commonly used refrigeration oils. In that case, a refrigeration oil that is superior in terms of compatibility with the mixture and its ability to improve the stability of the mixture can be appropriately selected as needed. As the base oil of the refrigeration oil, at least one selected from the group consisting of polyalkylene glycol (PAG), polyol ester (POE), and polyvinyl ether (PVE) is preferred. In addition to the base oil, the refrigeration oil may further contain additives.

[0074] For refrigeration oil, it is preferable that the kinematic viscosity at 40°C is between 5 cSt and 400 cSt, as this tends to improve lubricity.

[0075] The refrigerant oil-containing working fluid of this disclosure may optionally further contain at least one additive. Examples of additives include the following compatibilizers. The compatibilizer may be contained alone or in combination of two or more types.

[0076] The compatibilizer is not particularly limited and can be appropriately selected from commonly used compatibilizers. Examples of compatibilizers include polyoxyalkylene glycol ethers, amides, nitriles, ketones, chlorocarbons, esters, lactones, aryl ethers, fluoroethers, and 1,1,1-trifluoroalkanes. Polyoxyalkylene glycol ethers are particularly preferred as the compatibilizer.

[0077] 3. Alternative refrigerants The refrigerant compositions and refrigerant oil-containing working fluids of this disclosure include R12, R22, R134a, R404A, R407A, R407C, R407F, R407H, R410A, R413A, R417A, R422A, R422B, R422C, R422D, R423A, R424A, R426A, R427A, R430A, R43 It can be used as a substitute refrigerant for 4A, R437A, R438A, R448A, R449A, R449B, R449C, R452A, R452B, R454A, R454B, R454C, R455A, R465A, R474A, R479A, R502, R507, R513A, R1234yf, or R1234ze.

[0078] In particular, the refrigerant compositions of this disclosure are preferably used as substitute refrigerants for R32, R410A, or R404A.

[0079] 4. Method of using the refrigerant composition The refrigerant composition of this disclosure can be used in various refrigeration methods, refrigerators, etc., and can also be used as a working fluid in a refrigerator. For example, the refrigeration method may include a step of operating a refrigeration cycle using the refrigerant composition of this disclosure. Furthermore, the refrigerator may include the refrigerant composition of this disclosure as a working fluid.

[0080] 5. Method for stabilizing the refrigerant composition The refrigerant composition of this disclosure, by containing predetermined amounts of E-HFO-1132 and R32, is low GWP, ASHRAE mildly flammable (Class 2L), and has excellent refrigeration capacity, while also exhibiting excellent refrigerant stability (e.g., long-term storage stability) and being less prone to degradation. Therefore, including E-HFO-1132 and R32 in predetermined proportions, as in the refrigerant composition of this disclosure, is a suitable method for stabilizing the refrigerant composition. Furthermore, adjusting the amount of water in the refrigerant composition of this disclosure to an appropriate range further enhances the stabilizing effect of R32 on E-HFO-1132, so adjusting the amount of water in the composition is also a suitable stabilization method.

[0081] In identifying the inventions contained herein, the components (properties, structures, functions, etc.) described in each embodiment of this disclosure may be combined in any way. That is, this disclosure encompasses all subject matter consisting of any combination of the combinatable components described herein. [Examples]

[0082] The refrigerant compositions and the like of this disclosure will be described in more detail below with reference to examples, but the invention is not limited to the embodiments of these examples.

[0083] (Comparative Example 1a) A refrigerant consisting of difluoromethane (R32) was prepared according to the mixing ratios shown in Table 1.

[0084] (Comparative example 1b) A refrigerant consisting of R404A was prepared according to the mixing ratios shown in Table 1.

[0085] (Example 1-1) As shown in the mixing ratios in Table 1, a refrigerant was prepared containing 11.2% by mass of trans-1,2-difluoroethylene (E-HFO-1132) and 88.8% by mass of difluoromethane (R32) relative to the total mass of trans-1,2-difluoroethylene (E-HFO-1132) and difluoromethane (R32), and this refrigerant was obtained as a refrigerant composition.

[0086] (Examples 1-2, 1-3) A refrigerant composition was obtained in the same manner as in Example 1-1, except that the respective content ratios of E-HFO-1132 and R32 relative to the total mass were changed as shown in the blending ratios in Table 1.

[0087] (Comparative Example 1-1) A refrigerant composition was obtained in the same manner as in Example 1-1, except that the respective content ratios of E-HFO-1132 and R32 relative to the total mass were changed as shown in the blending ratios in Table 1.

[0088] (Example 2-1) As shown in the mixing ratios in Table 2, a refrigerant was prepared containing 33.4% by mass of E-HFO-1132 and 66.6% by mass of R32 relative to the total mass of E-HFO-1132 and R32, and this refrigerant was obtained as a refrigerant composition.

[0089] (Example 2-2) A refrigerant composition was obtained in the same manner as in Example 2-1, except that the respective content ratios of E-HFO-1132 and R32 relative to the total mass were changed as shown in the blending ratios in Table 2.

[0090] (Example 3-1) As shown in the mixing ratios in Table 2, a refrigerant was prepared containing 40.8% by mass of E-HFO-1132 and 59.2% by mass of R32 relative to the total mass of E-HFO-1132 and R32, and this refrigerant was obtained as a refrigerant composition.

[0091] (Example 3-2) A refrigerant composition was obtained in the same manner as in Example 3-1, except that the respective content ratios of E-HFO-1132 and R32 relative to the total mass were changed as shown in the blending ratios in Table 2.

[0092] (Example 4-1) As shown in the mixing ratios in Table 2, a refrigerant was prepared containing 52.0% by mass of E-HFO-1132 and 48.0% by mass of R32 relative to the total mass of E-HFO-1132 and R32, and this refrigerant was obtained as a refrigerant composition.

[0093] (Example 4-2) A refrigerant composition was obtained in the same manner as in Example 4-1, except that the respective content ratios of E-HFO-1132 and R32 relative to the total mass were changed as shown in the blending ratios in Table 2.

[0094] (Comparative Example 2-1) As shown in the mixing ratios in Table 2, a refrigerant was prepared containing 62.0% by mass of E-HFO-1132 and 38.0% by mass of R32 relative to the total mass of E-HFO-1132 and R32, and this refrigerant was obtained as a refrigerant composition.

[0095] (Example 5-1) Four refrigerant compositions prepared in Example 4-1 were prepared, and water was added to each refrigerant composition to adjust the water content relative to the total mass of the refrigerant to 0 ppm by mass (no addition), 10 ppm by mass, 100 ppm by mass, and 1000 ppm by mass. The four refrigerant compositions with adjusted water content were sealed in containers, and oxygen was blown into the containers to adjust the amount of oxygen relative to the total amount of refrigerant (total moles) to 0.01 mol%. In this way, four refrigerant compositions with water and oxygen content adjusted to predetermined ratios were obtained (sample numbers were designated as No. 26, No. 27, No. 28, and No. 29, respectively).

[0096] (Example 5-2) Four types of refrigerant compositions were obtained in which the water content and oxygen content were adjusted to predetermined ratios in the same manner as in Example 5-1, except that the amount of oxygen relative to the total amount of refrigerant (total moles) was adjusted to 0.15 mol% (these were designated as sample numbers No. 31, No. 32, No. 33, and No. 34, respectively).

[0097] (Example 5-3) Four types of refrigerant compositions were obtained in which the water content and oxygen content were adjusted to predetermined ratios in the same manner as in Example 5-1, except that the amount of oxygen relative to the total amount of refrigerant (total moles) was adjusted to 0.35 mol% (these were designated as sample numbers No. 36, No. 37, No. 38, and No. 39, respectively).

[0098] (Test Example 5-1) Five refrigerant compositions prepared in Example 4-1 were prepared, and water was added to each refrigerant composition to adjust the water content relative to the total mass of the refrigerant to 0 ppm by mass (no addition), 10 ppm by mass, 100 ppm by mass, 1000 ppm by mass, and 5000 ppm by mass. The five refrigerant compositions with adjusted water content were sealed in containers, and the amount of oxygen relative to the total amount of refrigerant (total moles) was adjusted to 0 mol% (below the detection limit) without blowing oxygen into the containers (deoxygenation treatment was performed). In this way, five refrigerant compositions with water content adjusted to predetermined ratios were obtained (sample numbers were designated as No. 21, No. 22, No. 23, No. 24, and No. 25, respectively).

[0099] (Test Example 5-2) A refrigerant composition was obtained in the same manner as in Example 5-1, except that the water content relative to the total mass of the refrigerant was adjusted to 5000 ppm by mass (sample number No. 30).

[0100] (Test Example 5-3) A refrigerant composition was obtained in the same manner as in Example 5-2, except that the water content relative to the total mass of the refrigerant was adjusted to 5000 ppm by mass (sample number No. 35).

[0101] (Test Example 5-4) A refrigerant composition was obtained in the same manner as in Example 5-3, except that the water content relative to the total mass of the refrigerant was adjusted to 5000 ppm by mass (sample number No. 40).

[0102] (Comparative Example 5-4) Five refrigerant compositions were obtained in the same manner as in Test Example 5-1, except that the refrigerant composition was changed to one consisting substantially only of E-HFO-1132, with the water content adjusted to a predetermined ratio (these were designated as Sample No. 1, No. 2, No. 3, No. 4, and No. 5, respectively).

[0103] (Comparative Example 5-5) Five refrigerant compositions consisting essentially of E-HFO-1132 were prepared. Water was added to each refrigerant composition to adjust the water content relative to the total mass of the refrigerant to 0 ppm (no addition), 10 ppm, 100 ppm, 1000 ppm, and 5000 ppm. These five refrigerant compositions with adjusted water content were sealed in containers, and oxygen was blown into the containers to adjust the oxygen content relative to the total amount of refrigerant (total moles) to 0.01 mol%. In this way, five refrigerant compositions with predetermined water and oxygen content were obtained (sample numbers No. 6, No. 7, No. 8, No. 9, and No. 10, respectively).

[0104] (Comparative Example 5-6) Five refrigerant compositions were obtained in which the water content and oxygen content were adjusted to predetermined ratios in the same manner as in Comparative Example 5-5, except that the oxygen content relative to the total amount of refrigerant (total moles) was adjusted to 0.15 mol% (these were designated as sample numbers No. 11, No. 12, No. 13, No. 14, and No. 15, respectively).

[0105] (Comparative Example 5-7) Four refrigerant compositions were obtained in which the water content and oxygen content were adjusted to predetermined ratios in the same manner as in Comparative Example 5-5, except that the oxygen content relative to the total amount of refrigerant (total moles) was adjusted to 0.35 mol% (these were designated as sample numbers No. 16, No. 17, No. 18, No. 19, and No. 20, respectively).

[0106] (Test Example 6-4) Five refrigerant compositions prepared in Example 1-2 were prepared, and water was added to each refrigerant composition to adjust the water content relative to the total mass of the refrigerant to 0 ppm by mass (no addition), 10 ppm by mass, 100 ppm by mass, 1000 ppm by mass, and 5000 ppm by mass. The five refrigerant compositions with adjusted water content were sealed in containers, and the amount of oxygen relative to the total amount of refrigerant (total moles) was adjusted to 0 mol% (below the detection limit) without blowing oxygen into the containers (deoxygenation treatment was performed). In this way, five refrigerant compositions with predetermined water content were obtained (sample numbers were designated as No. 41, No. 42, No. 43, No. 44, and No. 45, respectively).

[0107] (Example 6-1) Four refrigerant compositions prepared in Example 1-2 were prepared, and water was added to each refrigerant composition to adjust the water content relative to the total mass of the refrigerant to 0 ppm by mass (no addition), 10 ppm by mass, 100 ppm by mass, and 1000 ppm by mass. The four refrigerant compositions with adjusted water content were sealed in containers, and oxygen was blown into the containers to adjust the amount of oxygen relative to the total amount of refrigerant (total moles) to 0.01 mol%. In this way, four refrigerant compositions with water and oxygen content adjusted to predetermined ratios were obtained (sample numbers were designated as No. 46, No. 47, No. 48, and No. 49, respectively).

[0108] (Test Example 6-1) A refrigerant composition was obtained in the same manner as in Example 6-1, except that the water content relative to the total mass of the refrigerant was adjusted to 5000 ppm by mass (sample number No. 50).

[0109] (Example 6-2) Four refrigerant compositions prepared in Example 1-2 were prepared, and water was added to each refrigerant composition to adjust the water content relative to the total mass of the refrigerant to 0 ppm by mass (no addition), 10 ppm by mass, 100 ppm by mass, and 1000 ppm by mass. The four refrigerant compositions with adjusted water content were sealed in containers, and oxygen was blown into the containers to adjust the oxygen content relative to the total amount of refrigerant (total moles) to 0.15 mol%. In this way, four refrigerant compositions with water and oxygen content adjusted to predetermined ratios were obtained (sample numbers were designated as No. 51, No. 52, No. 53, and No. 54, respectively).

[0110] (Test Example 6-2) A refrigerant composition was obtained in the same manner as in Example 6-2, except that the water content relative to the total mass of the refrigerant was adjusted to 5000 ppm by mass (sample number No. 55).

[0111] (Example 6-3) Four refrigerant compositions prepared in Example 1-2 were prepared, and water was added to each refrigerant composition to adjust the water content relative to the total mass of the refrigerant to 0 ppm by mass (no addition), 10 ppm by mass, 100 ppm by mass, and 1000 ppm by mass. The four refrigerant compositions with adjusted water content were sealed in containers, and oxygen was blown into the containers to adjust the oxygen content relative to the total amount of refrigerant (total moles) to 0.35 mol%. In this way, four refrigerant compositions with water and oxygen content adjusted to predetermined ratios were obtained (sample numbers were designated as No. 56, No. 57, No. 58, and No. 59, respectively).

[0112] (Test Example 6-3) A refrigerant composition was obtained in the same manner as in Example 6-3, except that the water content relative to the total mass of the refrigerant was adjusted to 5000 ppm by mass (sample numbered No. 60).

[0113] (Comparative Example 7-1) A refrigerant was prepared containing 58% by mass of trans-1,2-difluoroethylene (E-HFO-1132) and 42% by mass of pentafluoroethane (R125) relative to the total mass of trans-1,2-difluoroethylene (E-HFO-1132) and pentafluoroethane (R125), and this refrigerant was obtained as a refrigerant composition. Five of these refrigerant compositions were prepared, and water was added to each composition to adjust the water content relative to the total mass of the refrigerant to 0 ppm by mass (no addition), 10 ppm by mass, 100 ppm by mass, 1000 ppm by mass, and 5000 ppm by mass. The five refrigerant compositions with adjusted water content were sealed in containers, and the amount of oxygen relative to the total amount of refrigerant (total moles) was adjusted to 0 mol% (below the detection limit) without blowing oxygen into the containers (deoxygenation treatment was performed). In this way, five types of refrigerant compositions were obtained in which the water content was adjusted to a predetermined ratio (the sample numbers were designated as No. 61, No. 62, No. 63, No. 64, and No. 65, respectively).

[0114] (Comparative Example 7-2) A refrigerant composition was obtained in the same manner as in Comparative Example 7-1, except that the amount of oxygen relative to the total amount (total number of moles) of refrigerant was adjusted to 0.01 mol% (sample numbers were No. 66, No. 67, No. 68, No. 69, and No. 70, respectively).

[0115] (Comparative Example 7-3) A refrigerant composition was obtained in the same manner as in Comparative Example 7-1, except that the amount of oxygen relative to the total amount (total number of moles) of refrigerant was adjusted to 0.15 mol% (the sample numbers were No. 71, No. 72, No. 73, No. 74, and No. 75, respectively).

[0116] (Comparative Example 7-4) A refrigerant composition was obtained in the same manner as in Comparative Example 7-1, except that the amount of oxygen relative to the total amount (total number of moles) of refrigerant was adjusted to 0.35 mol% (sample numbers were No. 76, No. 77, No. 78, No. 79, and No. 80, respectively).

[0117] (Evaluation method) GWP The GWP of E-HFO-1132 was set to 1, and the GWP of R32 was evaluated based on the values ​​from the IPCC (Intergovernmental Panel on Climate Change) Fourth Assessment Report.

[0118] (Evaluation method) COP The COP (Coefficient of Performance) and refrigeration capacity of the refrigerant composition were determined by performing theoretical calculations of the refrigeration cycle under the following conditions, using the National Institute of Science and Technology (NIST) Reference Fluid Thermodynamic and Transport Properties Database (Refprop 10.0). Note that the refrigeration cycle calculations required physical property data for E-HFO-1132, which was obtained through actual measurements. (Conditions for performance comparison with R32) Evaporation temperature: 5℃ Condensation temperature: 45℃ Superheating temperature: 5K Supercooling temperature: 5K Compressor efficiency: 70% (Conditions for performance comparison with R404A) Evaporation temperature: -40℃ Condensation temperature: 40℃ Superheating temperature: 20K Supercooling temperature: 0K Compressor efficiency: 70% The COP was calculated based on the formula "(refrigeration capacity or heating capacity) / energy consumption," and the ratio of R32 or R404A to the COP (hereinafter referred to as the "COP ratio") was calculated. In addition, the refrigeration capacity was calculated as the ratio of R32 or R404A to the refrigeration capacity (hereinafter referred to as the "refrigeration capacity ratio").

[0119] From here Combustion rate Combustion tests were conducted on each of the refrigerant compositions obtained in each example and comparative example, and the WCF combustion rate and WCFF combustion rate were measured. Specifically, the composition of each refrigerant composition was set to WCF, and leakage simulations were performed using NIST Standard Reference Data Base Refleak Version 4.0 under the conditions of Equipment, Storage, Shipping, Leak, and Recharge according to the ASHRAE 34-2013 standard, and the most flammable fraction was set to WCFF. Furthermore, the combustion rate was measured according to the ANSI / ASHRAE 34-2013 standard. Combustion rates of 10 cm / s or less for both WCF and WCFF were defined as "2L class (slightly flammable)". The combustion rate tests were conducted using known methods, specifically using the combustion test conditions and combustion apparatus disclosed in Japanese Patent Publication No. 2021-1325. If combustion did not occur, it was defined as "non-combustible".

[0120] Presence of disproportionation reaction The presence or absence of disproportionation reactions was investigated for the refrigerant compositions prepared in each example and comparative example. Specifically, the refrigerant composition was transferred and filled into a SUS test container (capacity 38cc), heated to 150°C to raise the internal pressure to 3MPa, and then 30J of energy was applied to the refrigerant composition by applying voltage to a Pt wire placed inside the container to melt it, and the pressure and temperature increases were observed. The presence or absence of disproportionation reactions was determined as "non-explosive" or "explosive" based on the presence or absence of a rapid increase in pressure and temperature inside the apparatus according to the following criteria. ≪Judgment criteria≫ "Non-explosive": The temperature or pressure after Pt wire cutting is less than twice the normal level, and no rapid disproportionation reaction has occurred. "Explosion": The temperature or pressure after the Pt wire cutting reached more than twice its original level, causing a rapid disproportionation reaction.

[0121] Stability test of refrigerant composition Stability tests were performed on each of the refrigerant compositions obtained in each example and comparative example as follows: E-HFO-1132 was added to a glass tube (ID 8 mmΦ × OD 12 mmΦ × L 300 mm) with one end sealed by heat, so that the content of E-HFO-1132 in the refrigerant was 0.01 mol. The tube was sealed by heat. This tube was left to stand in a constant temperature bath at 150°C and kept in this state for one week. After that, the tube was removed from the constant temperature bath and cooled, and the stability of the refrigerant composition was evaluated by checking its appearance and analyzing the acid content (acid component) in the gas inside the tube. In this stability test, the analysis of the acid content in the gas was performed by the following method: The gas remaining inside the cooled tube was completely solidified using liquid nitrogen. Then the tube was opened and gradually thawed, and the gas was collected in a Tedlar bag. 5 g of pure water was poured into this Tedlar bag, and the acid was extracted into the pure water while keeping it in good contact with the collected gas. The extract was detected by ion chromatography to find fluoride ions (F - The content (mass ppm) of ) was measured.

[0122] Tables 1 and 2 show the composition of the refrigerant in the refrigerant compositions prepared in each example and comparative example, as well as the evaluation results (GWP, COP ratio, refrigeration capacity ratio, presence or absence of disproportionation reaction). In Table 1, the COP ratio (vs. R32) refers to the ratio of the COP of the refrigerant composition when a refrigerant consisting only of R32 is set to 100%, and the COP ratio (vs. R404A) refers to the ratio of the COP of the refrigerant composition when a refrigerant consisting only of R404A is set to 100%. Furthermore, the refrigeration capacity ratio (vs. R32) refers to the ratio of the refrigeration capacity of the refrigerant composition when a refrigerant consisting only of R32 is set to 100%, and the refrigeration capacity ratio (vs. R404A) refers to the ratio of the refrigeration capacity of the refrigerant composition when a refrigerant consisting only of R404A is set to 100%.

[0123] Tables 1 and 2 show that the refrigerant compositions prepared in the examples had low GWP and, considering the results of refrigeration capacity and combustion rate, exhibited excellent performance as refrigerants. Furthermore, even the refrigerant composition of Example 4-2, which had a high content of E-HFO-1132, was "non-explosive" and demonstrated high safety.

[0124] Tables 3 and 4 (Table 3 contains samples No. 1 to 20, and Table 4 contains samples No. 21 to 40) show the water content, oxygen content, and evaluation results (acid content, appearance (presence or absence of solid matter)) for Examples 5-1 to 5-3, Comparative Examples 5-4 to 5-7 (Table 3), and test examples. Specifically, Table 3 (samples No. 1 to 20) shows the evaluation results of the stability test for refrigerant compositions consisting only of E-HFO-1132, and Table 4 shows the evaluation results of the stability test for refrigerant compositions consisting of 52% by mass of E-HFO-1132 and 48% by mass of R32.

[0125] Tables 3 and 4 show that in Test Example 5-1 (No. 21-25), the composition did not contain oxygen (it was below the detection limit), so E-HFO-1132 was stable regardless of the presence or absence of water. However, when the water content was too high, as in No. 25, the formation of solid matter in the composition was observed even in the absence of oxygen.

[0126] In each example, the refrigerant composition showed suppressed acid generation, E-HFO-1132 was stable, and no solid matter was visually observed. When the water content was too high, as in Nos. 30, 35, and 40, decomposition of E-HFO-1132 was less likely, but the generation of solid matter was observed.

[0127] Furthermore, as can be seen by comparing samples No. 7 with No. 27, No. 8 with No. 28, No. 12 with No. 32, No. 13 with No. 33, No. 17 with No. 37, No. 18 with No. 38, and No. 19 with No. 39, it was demonstrated that E-HFO-1132 is particularly remarkably stabilized when the refrigerant contains R32 and a predetermined amount of water.

[0128] Therefore, a refrigerant composition containing predetermined amounts of E-HFO-1132 and R32, and a predetermined amount of water, exhibited particularly improved stability as a refrigerant, and it was found that the stability-enhancing effect of E-HFO-1132 was enhanced by the combined action of R32 and water.

[0129] The results in Table 6 show that refrigerant compositions containing R125 were less stable than those containing R32.

[0130] [Table 1]

[0131] [Table 2]

[0132] [Table 3]

[0133] [Table 4]

[0134] [Table 5]

[0135] [Table 6]

Claims

1. A composition containing a refrigerant, The aforementioned refrigerant is It contains trans-1,2-difluoroethylene and difluoromethane in total at a concentration of 99.5% by mass or more of the total refrigerant. The aforementioned refrigerant is A refrigerant composition containing 11.2% by mass or more and 19.5% by mass or less of trans-1,2-difluoroethylene, relative to the total mass of trans-1,2-difluoroethylene and difluoromethane.

2. A composition containing a refrigerant, The aforementioned refrigerant is It contains trans-1,2-difluoroethylene and difluoromethane in total at a concentration of 99.5% by mass or more of the total refrigerant. The aforementioned refrigerant is (i), (ii), and (iii) below (i) The total mass of trans-1,2-difluoroethylene and difluoromethane is 33.4% or more and 37.5% or less of trans-1,2-difluoroethylene; (ii) The total mass of trans-1,2-difluoroethylene and difluoromethane is 40.8% or more and 49.5% or less of trans-1,2-difluoroethylene; (iii) Trans-1,2-difluoroethylene is contained in an amount of 52.0% by mass or more and 58.2% by mass or less relative to the total mass of trans-1,2-difluoroethylene and difluoromethane; A refrigerant composition that satisfies at least one of the following conditions.

3. A composition containing a refrigerant, The aforementioned refrigerant is It contains trans-1,2-difluoroethylene and difluoromethane in total at a rate of 99.5% or more by mass relative to the total amount of refrigerant. The aforementioned refrigerant is The total mass of trans-1,2-difluoroethylene and difluoromethane is such that trans-1,2-difluoroethylene is present in an amount of 11.2% or more by mass and 60.0% or less by mass. The refrigerant contains 0.1% by mass or less of water relative to its total mass. A refrigerant composition in which the oxygen content is 0.35 mol% or less relative to the total amount of the refrigerant.

4. Among the aforementioned refrigerants, The total content of compounds selected from the group consisting of methylamine, acetylene, HFO-1141, HFO-1123, HFC-143a, HFC-134a, HFO-1132a, Z-HFO-1132, HFO-1243zf, HFC-245cb, HCFC-1122, HCFC-124, CFC-1113, and 3,3,3-trifluoropropyne is 0.5% by mass or less of the total mass of the refrigerant. The refrigerant composition according to any one of claims 1 to 3.

5. The refrigerant contains 0.1% by mass or less of water relative to its total mass. The refrigerant composition according to claim 1 or 2, wherein the oxygen content is 0.35 mol% or less relative to the total amount of the refrigerant.

6. A refrigerant composition according to any one of claims 1 to 3, which is used as a substitute refrigerant for R32, R410A, or R404A.

7. A refrigeration method comprising the step of operating a refrigeration cycle using a refrigerant composition according to any one of claims 1 to 3.

8. A refrigerator comprising a refrigerant composition according to any one of claims 1 to 3 as a working fluid.

9. Use of the refrigerant composition according to any one of claims 1 to 3 as a working fluid in a refrigerator.

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