초록 ▼

The present invention proposes a lubricating oil for refrigerators comprising, as the base oil, a polyester-based derivative or a polyvinyl ether derivative and a polycarbonate-based oxygenated compound; a polyoxyalkylene glycol derivative; or a polyester-based derivative or a polyvinyl ether deriva

The present invention proposes a lubricating oil for refrigerators comprising, as the base oil, a polyester-based derivative or a polyvinyl ether derivative and a polycarbonate-based oxygenated compound; a polyoxyalkylene glycol derivative; or a polyester-based derivative or a polyvinyl ether derivative and a polyoxyalkylene glycol derivative. The lubricating oil exhibits excellent miscibility with a refrigerant having one carbon atom and no chlorine atoms and, in particular, with difluoromethane and provides a hydraulic fluid composition exhibiting excellent antiwear, lubricity and stability.

대표청구항 ▼

1. A hydraulic fluid composition which comprises (A) a refrigerant consisting of difluoromethane and (B) a lubricating oil which comprises, as a base oil, a polyoxyalkylene glycol derivative with a kinematic viscosity of 3 to 2,000 mm2/s at 40° C. and, as a main component thereof, having at least on

1. A hydraulic fluid composition which comprises (A) a refrigerant consisting of difluoromethane and (B) a lubricating oil which comprises, as a base oil, a polyoxyalkylene glycol derivative with a kinematic viscosity of 3 to 2,000 mm2/s at 40° C. and, as a main component thereof, having at least one constituting unit represented by general formula (III): wherein R7 to R10 each independently represent hydrogen atom, a monovalent hydrocarbon group having 1 to 10 carbon atoms or a group represented by general formula (IV): wherein R11 and R12 each independently representing hydrogen atom, a monovalent hydrocarbon group having 1 to 20 carbon atoms or an alkoxyalkyl group having 2 to 20 carbon atoms, R13 representing an alkylene group having 2 to 5 carbon atoms, a substituted alkylene group having an alkyl group as a substituent and 2 to 5 carbon atoms in an entire group or a substituted alkylene group having an alkoxyalkyl group as a substituent and 4 to 10 carbon atoms in an entire group, R14 representing a monovalent hydrocarbon group having 1 to 10 carbon atoms and n representing an integer of 0 to 20; and at least one of R7 to R10 represents a group represented by general formula (IV). 2. The hydraulic fluid according to claim 1, wherein a kinematic viscosity at 40° C. of said lubricating oil is 7 to 200 mm2/s and a viscosity index of said lubricating oil is 40 or greater. 3. The hydraulic fluid according to claim 1, which further comprises an acid catcher. 4. The hydraulic fluid according to claim 1, which further comprises at least one additive selected from a group consisting of extreme pressure agents, oiliness agents and antioxidants. 5. The hydraulic fluid composition according to claim 1, which comprises said (A) and said (B) in amounts such that a ratio of an amount by weight of said (A) to an amount by weight of said (B) is in a range of 5:95 to 99:1. 6. The hydraulic fluid according to claim 1, wherein one of R7 and R9 represents a group represented by the general formula (IV), and the other of R7 and R9, R8 and R10 each represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms. 7. The hydraulic fluid according to claim 1, wherein the polyalkylene glycol derivative is a homopolymer comprising constituting units represented by the general formula (III). 8. The hydraulic fluid according to claim 1, wherein the polyalkylene glycol derivative is a copolymer comprising two or more different constituting units represented by the general formula (III). 9. The hydraulic fluid according to claim 1, wherein the polyalkylene glycol derivative is a copolymer comprising constituting units represented by the general formula (III) and other constituting units represented by general formula (XVIII): wherein R63 to R66 each represent hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 10. The hydraulic fluid according to claim 7, wherein the homopolymer comprises 1 to 200 constituting units A represented by the general formula (III) and having an hydroxyl group, an acyloxyl group having 1 to 10 carbon atoms, an alkoxyl group having 1 to 10 carbon atoms or an aryloxyl group at each chain end. 11. The hydraulic fluid according to claim 8, wherein the copolymer comprises two constituting units A and B each represented by the general formula (III) each in a number of 1 to 200, and having an hydroxyl group, an acyloxyl group having 1 to 10 carbon atoms, an alkoxyl group having 1 to 10 carbon atoms or an aryloxyl group at each chain end. 12. The hydraulic fluid according to claim 9, wherein the copolymer comprises 1 to 200 constituting units A represented by general formula (III) and 1 to 200 constituting units C represented by general formula (XVIII), and having an hydroxyl group, an acyloxyl group having 1 to 10 carbon atoms, an alkoxyl group having 1 to 10 carbon atoms or an aryloxyl groups at each chain end. 13. The hydraulic fluid according to claim 6, wherein the polyalkylene glycol derivative is a homopolymer comprising constituting units represented by the general formula (III). 14. The hydraulic fluid according to claim 6, wherein the polyalkylene glycol derivative is a copolymer comprising two or more different constituting units represented by the general formula (III). 15. The hydraulic fluid according to claim 6, wherein the polyalkylene glycol derivative is a copolymer comprising constituting units represented by the general formula (III) and other constituting units represented by general formula (XVIII): wherein R63 to R66 each represent hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 16. The hydraulic fluid according to claim 13, wherein the homopolymer comprises 1 to 200 constituting units A represented by the general formula (III) and having an hydroxyl group, an acyloxyl group having 1 to 10 carbon atoms, an alkoxyl group having 1 to 10 carbon atoms or an aryloxyl group at each chain end. 17. The hydraulic fluid according to claim 14, wherein the copolymer comprises two constituting units A and B each represented by the general formula (III) each in a number of 1 to 200, and having an hydroxyl group, an acyloxyl group having 1 to 10 carbon atoms, an alkoxyl group having 1 to 10 carbon atoms or an aryloxyl group at each chain end. 18. The hydraulic fluid according to claim 15, wherein the copolymer comprises 1 to 200 constituting units A represented by general formula (III) and 1 to 200 constituting units C represented by general formula (XVIII), and having an hydroxyl group, an acyloxyl group having 1 to 10 carbon atoms, an alkoxyl group having 1 to 10 carbon atoms or an aryloxyl groups at each chain end.