Refrigerator oil and working fluid composition for refrigerator
In an aspect, the present invention provides a refrigerating machine oil comprising a poly(meth)acrylate as a base oil, wherein the poly(meth)acrylate comprises a hydrogenated poly(meth)acrylate, a content of a unit having a carbon-carbon double bond present at a terminal in the poly(meth)acrylate is 6% by mole or less relative to total units constituting the poly(meth)acrylate, and a kinematic viscosity at 40° C. of the hydrogenated poly(meth)acrylate is 1 to 1000 mm2/s, the refrigerating machine oil being used with a refrigerant comprising a refrigerant selected from difluoromethane, a mixture of difluoromethane and pentafluoroethane, a mixture of difluoromethane, pentafluoroethane, and 1, 1, 1, 2-tetrafluoroethane, a mixture of pentafluoroethane, 1, 1, 1, 2-tetrafluoroethane, and 1, 1, 1-trifluoroethane, an unsaturated hydrofluorocarbon, a hydrocarbon, and carbon dioxide.
1. A working fluid composition for a refrigerating machine, comprising:
a refrigerating machine oil comprising
a base oil,
wherein the base oil comprises
poly(meth)acrylate comprised of a hydrogenated poly(meth)acrylate, a content of a unit having a carbon-carbon double bond present at a terminal in the poly(meth)acrylate is 6% by mole or less relative to total units constituting the poly(meth)acrylate, and a kinematic viscosity at 40° C. of the hydrogenated poly(meth)acrylate is 1 to 1000 mm 2 /s, wherein an amount of the hydrogenated poly(meth)acrylate is 30% by mass or less based on the total amount of the poly(meth)acrylate, and
an oil other than the hydrogenated poly(meth)acrylate; and
a refrigerant comprising a refrigerant selected from the group consisting of
a mixture of difluoromethane, pentafluoroethane, and 1,1,1,2-tetrafluoroethane,
an unsaturated hydrofluorocarbon, and
a hydrocarbon,
wherein
a mass ratio of the refrigerating machine oil/the refrigerant is from 2/100 to 400/100,
a content of the base oil is 80% by mass or more, based on the total amount of the refrigerating machine oil, and
the hydrogenated poly(meth)acrylate has a structural unit represented by the following formula (1):
wherein R 1 , R 2 , and R 3 represent a hydrogen atom or a hydrocarbon group, and R 4 is an alkyl group having 1 to 4 carbon atoms.
2. The working fluid composition for a refrigerating machine according to claim 1 , wherein the refrigerant comprises a mixture of difluoromethane, pentafluoroethane, and 1,1,1,2-tetrafluoroethane.
3. The working fluid composition for a refrigerating machine according to claim 1 , wherein the refrigerant comprises an unsaturated hydrofluorocarbon.
4. The working fluid composition for a refrigerating machine according to claim 1 , wherein the hydrocarbon group represented by R 4 in the formula (1) is an alkyl group having 2 carbon atoms.
5. The working fluid composition for a refrigerating machine according to claim 1 , wherein R 1 and R 2 in the formula (1) each are a hydrogen atom and R 3 in the formula (1) is a hydrogen atom or a methyl group.
6. The working fluid composition for a refrigerating machine according to claim 1 , wherein the average degree of polymerization of the hydrogenated poly(meth)acrylate is 3 to 20.
7. The working fluid composition for a refrigerating machine according to claim 3 , wherein the unsaturated hydrofluorocarbon is selected from the group consisting of 1,2,3,3,3-pentafluoropropene (HFO-1225ye), 1,3,3,3-tetrafluoropropene (HFO-1234ze), 2,3,3,3-tetrafluoropropene (HFO-1234yf), 1,2,3,3-tetrafluoropropene (HFO-1234ye), and 3,3,3-trifluoropropene (HFO-1243zf).
8. The working fluid composition for a refrigerating machine according to claim 1 , wherein the refrigerant comprises a hydrocarbon selected from the group consisting of methane, ethylene, ethane, propylene, propane (R290), cyclopropane, normal butane, isobutane, cyclobutane, methylcyclopropane, 2-methylbutane, and normal pentane.
9. The working fluid composition for a refrigerating machine according to claim 1 , wherein a mass ratio of the refrigerating machine oil/the refrigerant is from 2/100 to 30/70.
10. The working fluid composition for a refrigerating machine according to claim 1 , wherein a mass ratio of the refrigerating machine oil/the refrigerant is from 10/90 to 30/70.
11. A method for improving a compatibility of a working fluid composition for a refrigerating machine comprising,
(a) preparing a refrigerating machine oil comprising a base oil consisting of a poly(meth)acrylate, and
(b) mixing a refrigerant and the refrigerating machine oil, wherein the poly(meth)acrylate has a structural unit represented by the following formula
wherein R 1 and R 2 each are a hydrogen atom and R 3 be a hydrogen atom or a methyl group, and R 4 is an alkyl group having 1 to 10 carbons, and
a content of a unit having a carbon-carbon double bond present at a terminal in the poly(meth)acrylate is 6% by mole or less relative to total units constituting the poly(meth)acrylate;
an amount of the hydrogenated poly(meth)acrylate is 30% by mass or less based on the total amount of the poly(meth)acrylate; and
the refrigerant comprises at least one refrigerant selected from the group consisting of a mixture of difluoromethane, pentafluoroethane, and 1,1,1,2-tetrafluoroethane, a mixture of pentafluoroethane, 1,1,1,2-tetrafluoroethane, and 1,1,1-trifluoroethane, an unsaturated hydrofluorocarbon, and a hydrocarbon.
12. The method for improving a compatibility of a working fluid composition for a refrigerating machine according to claim 11 , wherein the refrigerant comprising a refrigerant selected from the group consisting of a mixture of difluoromethane, pentafluoroethane, and 1,1,1,2-tetrafluoroethane, an unsaturated hydrofluorocarbon, and a hydrocarbon;
the unsaturated hydrofluorocarbon is selected from the group consisting of 1,3,3,3-tetrafluoropropene (HFO-1234ze), and 2,3,3,3-tetrafluoropropene (HFO-1234yf), 1,2,3,3-tetrafluoropropene (HFO-1234ye); and
the hydrocarbon is selected from the group consisting of propane (R290), normal butane, isobutane, and 2-methylbutane.
13. The method for improving a compatibility of a working fluid composition for a refrigerating machine according to claim 11 , wherein a mass ratio of the refrigerating machine oil/the refrigerant is from 2/100 to 30/70.
14. A working fluid composition for a refrigerating machine, comprising
a refrigerant; and
a refrigerating machine oil comprising a base oil consisting of a poly(meth)acrylate,
wherein the refrigerant comprising a refrigerant selected from the group consisting of
a mixture of difluoromethane, pentafluoroethane, and 1,1,1,2-tetrafluoroethane,
an unsaturated hydrofluorocarbon, and
a hydrocarbon,
the unsaturated hydrofluorocarbon is selected from the group consisting of 1,3,3,3-tetrafluoropropene (HFO-1234ze), and 2,3,3,3-tetrafluoropropene (HFO-1234yf), 1,2,3,3-tetrafluoropropene (HFO-1234ye), and
the hydrocarbon is selected from the group consisting of propane (R290), normal butane, isobutane, and 2-methylbutane,
a mass ratio of the refrigerating machine oil/the refrigerant is from 2/100 to 400/100; and the poly(meth)acrylate has a structural unit represented by the following formula (1):
wherein R 1 and R 2 each are a hydrogen atom and R 3 be a hydrogen atom or a methyl group, and R 4 is an alkyl group having 1 to 10 carbons,
the poly(meth)acrylate contains a hydrogenated poly(meth)acrylate, and
a content of a unit having a carbon-carbon double bond present at a terminal in the poly(meth)acrylate is greater than 1% by mole and 6% by mole or less relative to total units constituting the poly(meth)acrylate.
15. The working fluid composition for a refrigerating machine according to claim 14 , wherein a mass ratio of the refrigerating machine oil/the refrigerant is from 2/100 to 30/70.
16. The working fluid composition for a refrigerating machine according to claim 14 , wherein a mass ratio of the refrigerating machine oil/the refrigerant is from 10/90 to 30/70.
17. The working fluid composition for a refrigerating machine according to claim 14 , wherein R 4 in the formula (1) is an alkyl group having 1 to 4 carbons.
18. The working fluid composition for a refrigerating machine according to claim 14 , wherein an amount of the hydrogenated poly(meth)acrylate is 30% by mass or more based on the total amount of the refrigerating machine oil.
19. The working fluid composition for a refrigerating machine according to claim 14 , wherein an amount of the hydrogenated poly(meth)acrylate is 30% by mass or less based on the total amount of the poly(meth)acrylate.