Patent ID: 8349206

Claim:
A process for lubricating a refrigerator, comprising: contacting moving parts of the refrigerator with a refrigerating machine oil; wherein the refrigerating machine oil comprises: a base oil comprising as a main component, at least one of: a polyvinyl ether, having a repeating unit of formula (I): wherein R 1 , R 2 and R 3 are respectively a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, and may be the same or different; R 4 is a divalent hydrocarbon group having 1 to 10 carbon atoms; R 5 is a hydrocarbon group having 1 to 20 carbon atoms; k is a number of 0 to 10 on average; R 1 to R 5 in one repeating unit may be respectively the same as or different from those in the other repeating units; and when k is 2 or more, a plurality of the R 40 groups may be the same or different, and a polyoxyalkylene glycol derivative of formula (II): R 6 —[(OR 7 ) m —OR 8 ] n (II) wherein R 6 is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an acyl group having 2 to 10 carbon atoms or an aliphatic hydrocarbon group having 1 to 10 carbon atoms which contain 2 to 6 bonding sites; R 7 is an alkylene group having 2 to 4 carbon atoms; R 8 is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or an acyl group having 2 to 10 carbon atoms; n is an integer of 1 to 6; and m is a number of more than 2 but not more than 20 on average; wherein the refrigerator comprises a hydrocarbon based refrigerant, a kinematic viscosity of the refrigerating machine oil is 1 to 8 mm 2 /s as measured at 40° C., and the refrigerator comprises a sliding portion which is made of an engineering plastic material, or provided thereon with an organic coating film.