Refrigerator oil, and working fluid composition for refrigerators
The refrigerating machine oil according to the present invention comprises a polyalkylene glycol represented by the following formula (1): R 1 —(OR 3 ) n —OR 2 (1) [R 1 and R 2 may be the same or different from each other and each represent a hydrogen atom, an alkyl group having from 1 to 5 carbon atoms, or an acyl group having from 2 to 5 carbon atoms, R 3 represents an alkylene group having from 2 to 4 carbon atoms, n represents an integer such that a number average molecular weight of the polyalkylene glycol represented by the formula (1) is from 1000 to 2500] the polyalkylene glycol having a ratio of the weight average molecular weight Mw to the number average molecular weight Mn, Mw/Mn, of from 1.00 to 1.15, the refrigerating machine oil being used with a mildly flammable hydrofluorocarbon refrigerant.
1. A refrigerating machine oil comprising a polyalkylene glycol represented by the following formula (1):
R 1 —(OR 3 ) n —OR 2 (1)
wherein R 1 and R 2 may be the same or different from each other and each represents a hydrogen atom, an alkyl group having from 1 to 5 carbon atoms, or an acyl group having from 2 to 5 carbon atoms, R 3 represents an alkylene group having from 2 to 4 carbon atoms, n represents an integer such that a number average molecular weight of the polyalkylene glycol represented by the formula (1) is from 1000 to 1500;
the polyalkylene glycol having a ratio of a weight average molecular weight Mw to the number average molecular weight Mn, Mw/Mn, of from 1.00 to 1.13, and a kinematic viscosity at 100° C. of from 7 to 16 mm 2 /s, wherein a ratio of an ethylene group in the alkylene groups represented by R 3 in the polyalkylene glycol represented by the formula (1) is 30 mol % or less;
wherein a flash point of the polyalkylene glycol is 220° C. or more.
2. The refrigerating machine oil according to claim 1 , wherein R 1 and R 2 represent a methyl group.
3. The refrigerating machine oil according to claim 1 , wherein an autoignition point of the polyalkylene glycol is 330° C. or more.
4. The refrigerating machine oil according to claim 1 , wherein the Mw/Mn of the polyalkylene glycol is from 1.02 to 1.13.
5. The refrigerating machine oil according to claim 1 , wherein the Mw/Mn of the polyalkylene glycol is from 1.04 to 1.13.
6. The refrigerating machine oil according to claim 1 , wherein the content of the polyalkylene glycol in the refrigerating machine oil is 80% by mass or more.
7. A working fluid composition for a refrigerating machine, comprising:
the refrigerating machine oil according to claim 1 and
a refrigerant consisting of at least one mildly flammable hydrofluorocarbon refrigerant included in the A2L classification in the flammability classification of ASHRAE (The American Society of Heating, Refrigerating and Air-conditioning Engineers) and selected from the group consisting of difluoromethane, 1,3,3,3-tetrafluoropropene, and 2,3,3,3-tetrafluoropropene.
8. The working fluid composition for a refrigerating machine according to claim 7 , wherein R 1 and R 2 represent a methyl group.
9. The working fluid composition for a refrigerating machine according to claim 7 , wherein an autoignition point of the polyalkylene glycol is 330° C. or more.
10. The working fluid composition for a refrigerating machine according to claim 7 , wherein the number average molecular weight of the polyalkylene glycol is from 1000 to 1500.
11. The working fluid composition for a refrigerating machine according to claim 7 , wherein the Mw/Mn of the polyalkylene glycol is from 1.02 to 1.13.
12. The working fluid composition for a refrigerating machine according to claim 7 , wherein the Mw/Mn of the polyalkylene glycol is from 1.04 to 1.13.
13. The working fluid composition for a refrigerating machine according to claim 7 , wherein the content of the polyalkylene glycol in the refrigerating machine oil is 80% by mass or more.
14. The working fluid composition for a refrigerating machine according to claim 7 , wherein the mildly flammable hydrofluorocarbon refrigerant consists of at least one selected from the group consisting of difluoromethane, 1,3,3,3-tetrafluoropropene, and 2,3,3,3-tetrafluoropropene.
15. A working fluid composition for a refrigerating machine comprising:
a refrigerant consisting of at least one mildly flammable hydrofluorocarbon refrigerant included in the A2L classification in the flammability classification of ASHRAE (The American Society of Heating, Refrigerating and Air-conditioning Engineers) and selected from the group consisting of difluoromethane, 1,3,3,3-tetrafluoropropene, and 2,3,3,3-tetrafluoropropene and
a refrigerating machine oil comprising a polyalkylene glycol represented by the following formula (1):
R 1 —(OR 3 ) n —OR 2 (1)
wherein R 1 and R 2 represent a methyl group, R 3 represents an alkylene group having from 2 to 4 carbon atoms, n represents an integer such that a number average molecular weight of the polyalkylene glycol is from 1000 to 1500, and wherein a ratio of an ethylene group in the alkylene groups represented by R 3 in the polyalkylene glycol is 30 mol % or less;
the polyalkylene glycol having a ratio of a weight average molecular weight Mw to the number average molecular weight Mn, Mw/Mn, of from 1.04 to 1.13 and a kinematic viscosity at 100° C. of from 7 to 16 mm 2 /s, and
a content of the polyalkylene glycol in the refrigerating machine oil being 80% by mass or more; and
wherein a flash point of the polyalkylene glycol is 220° C. or more.
16. The working fluid composition for a refrigerating machine according to claim 15 , wherein an autoignition point of the polyalkylene glycol is 330° C. or more.