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JP-7857514-B2 - Foam inhibitor for refrigerant oil, method for suppressing foaming in refrigerant oil, use for suppressing foaming in refrigerant oil, refrigerant oil, and working fluid composition

JP7857514B2JP 7857514 B2JP7857514 B2JP 7857514B2JP-7857514-B2

Inventors

  • 関 由真
  • 木村 武史
  • 尾形 英俊
  • 川口 昌輝

Assignees

  • ＥＮＥＯＳ株式会社

Dates

Publication Date
20260512
Application Date
20250225
Priority Date
20240229

Claims (4)

  1. A method for suppressing foaming in refrigeration oil containing polyalkylene glycol, The process includes selecting a compound represented by the following formula (1) as the polyalkylene glycol, [In the formula, R1 and R2 are each independently a hydrogen atom or an alkyl group, R3 is an ethylene group or a propylene group, and m is an integer of 2 or more.] A method in which, in the compound represented by formula (1), the molar ratio of the hydrogen atom to the alkyl group is 40/60 or more and 60/40 or less, and the molar ratio of the ethylene group to the propylene group is 10/90 or less.
  2. The method according to claim 1, wherein the molar ratio of the ethylene group to the propylene group is 0/100.
  3. The use of the compound represented by the following formula (1) to suppress foaming in refrigerant oil, [In the formula, R1 and R2 are each independently a hydrogen atom or an alkyl group, R3 is an ethylene group or a propylene group, and m is an integer of 2 or more.] In the compound represented by formula (1) above, the molar ratio of the hydrogen atom to the alkyl group is 40/60 or more and 60/40 or less, and the molar ratio of the ethylene group to the propylene group is 10/90 or less.
  4. The use according to claim 3, wherein the molar ratio of the ethylene group to the propylene group is 0/100.

Description

This disclosure relates to foam inhibitors for refrigerant oil, methods for suppressing foaming in refrigerant oil, uses for suppressing foaming in refrigerant oil, refrigerant oil, and working fluid compositions. Refrigerant oil used in refrigerators, air conditioners, and other refrigeration equipment is used together with the refrigerant. As the refrigerant is compressed and vaporized, a problem called foaming can occur, where bubbles form in the refrigerant oil. When foaming occurs in refrigerant oil, it can lead to increased operating noise and cavitation in the refrigerant compressor. Conventionally, it has been common practice to suppress foaming by adding silicone oil as an antifoaming agent to the refrigerant oil (for example, Patent Document 1). Japanese Patent Publication No. 2005-162883 One embodiment of the present invention is a foaming inhibitor for refrigerant oil containing a compound represented by the following formula (1) (hereinafter also referred to as "PAG compound"). In the formula, R1 and R2 are each independently a hydrogen atom or an alkyl group, R3 is an ethylene group or a propylene group, and m is an integer of 2 or more. The alkyl groups represented by R1 and R2 may be linear or branched. The number of carbon atoms in the alkyl group may be 1 or more, 2 or more, or 3 or more, and may be 16 or less, 12 or less, 8 or less, or 5 or less, or 4. The alkyl group may preferably be an n-butyl group. In the PAG compound of this embodiment, the ratio of hydrogen atoms to alkyl groups in R1 and R2 (in other words, the ratio of terminal hydroxyl groups to terminal alkyl groups), and the ratio of ethylene groups to propylene groups in R3 (in other words, the ratio of ethylene oxide units (EO units) to propylene oxide units (PO units)) are within a specific range. As a result, when this PAG compound is used, foaming of refrigerant oil can be suppressed without the addition of an antifoaming agent. Specifically, with respect to R1 and R2 , the molar ratio of hydrogen atom/alkyl group (terminal hydroxyl group/terminal alkyl group) is 40/60 or more and 60/40 or less. The lower limit of this molar ratio may be 41/59 or more, 42/58 or more, 43/57 or more, 44/56 or more, 45/55 or more, 46/54 or more, or 47/53 or more. The upper limit of this molar ratio may be 59/41 or less, 58/42 or less, 57/43 or less, 56/44 or less, 55/45 or less, 54/46 or less, 53/47 or less, 52/48 or less, 51/49 or less, 50/50 or less, 49/51 or less, 48/52 or less, 47/53 or less, 46/54 or less, 45/55 or less, 44/56 or less, or 43/57 or less. Furthermore, with respect to R3 , the molar ratio of ethylene groups to propylene groups (molar ratio of EO units to PO units) is 10/90 or less. This molar ratio may also be 9/91 or less, 8/92 or less, 7/93 or less, 6/94 or less, or 5/95 or less, or 0/100 or less, 1/99 or more, 2/98 or more, 3/97 or more, 4/94 or more, or 5/95 or more, and from the viewpoint of further suppressing foaming of the refrigeration oil, it may also be 0/100 (i.e., R3 is all propylene groups). The molar ratio of hydrogen atom/alkyl group (terminal hydroxyl group/terminal alkyl group) and the molar ratio of ethylene group/propylene group (EO unit/PO unit) in PAG compounds can be determined by 13C -NMR measurement. Specifically, the molar ratio of hydrogen atom/alkyl group (terminal hydroxyl group/terminal alkyl group) can be determined by identifying the peaks originating from the carbon atoms constituting the hydrocarbon group having terminal hydroxyl groups and the peaks originating from the carbon atoms constituting the terminal alkyl group from the spectrum obtained by 13C -NMR measurement, and using the integral values of each peak as appropriate. The molar ratio of ethylene group/propylene group (EO unit/PO unit) can be determined by identifying the peaks originating from the carbon atoms constituting the EO unit and the peaks originating from the carbon atoms constituting the PO unit from the spectrum obtained by 13C-NMR measurement, and using the information on the EO unit and PO unit and the integral values of each peak as appropriate. The PAG compound may be at least one selected from the group consisting of compounds in which both R1 and R2 are hydrogen atoms (PAG compounds with hydroxyl groups at both ends), compounds in which both R1 and R2 are alkyl groups (PAG compounds with alkyl groups at both ends), and compounds in which one of R1 and R2 is a hydrogen atom and the other is an alkyl group (PAG compounds with a hydroxyl group at one end). It may contain two or more compounds selected from the group consisting of PAG compounds with hydroxyl groups at both ends, PAG compounds with alkyl groups at both ends, and PAG compounds with a hydroxyl group at one end, so as to satisfy the above-mentioned hydrogen atom/alkyl group molar ratio. When a single molecule of a PAG compound contains both structural units where R3 is an ethylene group (EO unit) and structural units where R3 is a propylene group (PO