Compressor, method for manufacturing compressor, and method for evaluating coating material for compressor

A method for manufacturing a compressor including a casing that accommodates a compression mechanism configured to compress a refrigerant and an electric motor configured to drive the compression mechanism, the method comprising:

• selecting a coating material for coating an outer surface of the casing, the selecting comprising:
• measuring a gas permeability rate of a coating film formed from the coating material at a plurality of temperatures including a first temperature below 0° C., or
• obtaining the gas permeability rate exhibited by the coating film at the plurality of temperatures, and
• selecting the coating material such that the gas permeability rate at each of the plurality of temperatures falls within a predetermined range.

A method for evaluating a coating material used for coating a compressor including a casing that accommodates a compression mechanism configured to compress a refrigerant and an electric motor configured to drive the compression mechanism, the method comprising:

• preparing a sample formed into a film from the coating material;
• measuring a gas permeability rate of the sample at a plurality of temperatures including a first temperature below 0° C., the gas permeability rate indicating the amount of gas permeating the sample per unit time;
• and
• evaluating a performance of the coating film formed from the coating material based on the gas permeability rate measured at each of the plurality of temperatures.