An aspect of the present invention provides a refrigerating machine oil containing: a lubricating base oil; a phosphorus-containing additive; and a polymer comprising an unsaturated carboxylic acid ester as a monomer unit.

An aspect of the present invention provides a refrigerating machine oil containing: a lubricating base oil; a phosphorus-containing additive; and a polymer comprising an unsaturated carboxylic acid ester as a monomer unit.

A defoaming agent obtainable by a process that includes: polymerizing (A) at least one polymerizable monomer in a composition, the composition comprising (C) a solvent and (B) at least one non-polymerizable polysiloxane dissolved in the (C) solvent, wherein the component (A) optionally comprises at least one Si-atom-containing monomer in an amount of less than 10 mass % on the basis of the total mass of the component (A).

A defoaming agent obtainable by a process that includes: polymerizing (A) at least one polymerizable monomer in a composition, the composition comprising (C) a solvent and (B) at least one non-polymerizable polysiloxane dissolved in the (C) solvent, wherein the component (A) optionally comprises at least one Si-atom-containing monomer in an amount of less than 10 mass % on the basis of the total mass of the component (A).

An aspect of the present invention provides a refrigerating machine oil containing a mixed base oil of a first hydrocarbon base oil having a kinematic viscosity at 40° C. of less than 6 mm.sup.2/s and a second hydrocarbon base oil having a kinematic viscosity at 40° C. of 6 mm.sup.2/s or more, wherein a (A)/(B) ratio is more than 1 and 1.5 or less, wherein (A) is a kinematic viscosity at 40° C. of the mixed base oil, and (B) is the kinematic viscosity at 40° C. of the first hydrocarbon base oil.

An aspect of the present invention provides a refrigerating machine oil containing a mixed base oil of a first hydrocarbon base oil having a kinematic viscosity at 40° C. of less than 6 mm.sup.2/s and a second hydrocarbon base oil having a kinematic viscosity at 40° C. of 6 mm.sup.2/s or more, wherein a (A)/(B) ratio is more than 1 and 1.5 or less, wherein (A) is a kinematic viscosity at 40° C. of the mixed base oil, and (B) is the kinematic viscosity at 40° C. of the first hydrocarbon base oil.

A method for the preparation of a sulfur-free copolymer proceeds by solution polymerization in the presence of a radical initiator, wherein the copolymer contains at least one alkyl methacrylate and maleic anhydride having a number average molecular weight of 3000 to 9000 g/mol.

A method for the preparation of a copolymer containing at least one alkyl methacrylate and maleic anhydride having a number average molecular weight of 4000 to 18000 g/mol proceeds by solution polymerization in the presence of a radical initiator.

A method for the preparation of a copolymer containing at least one alkyl methacrylate and maleic anhydride having a number average molecular weight of 4000 to 18000 g/mol proceeds by solution polymerization in the presence of a radical initiator.

There is provided an ultraviolet curable resin composition for a self-lubricating liner, including: a (meth)acrylate compound having an isocyanuric acid ring; at least one of (meth)acrylate having a phosphoric acid ester group and (meth)acrylate having a silane group: a polythiol compound; and a polytetrafluoroethylene resin as a solid lubricant.