Polyester insulation materials, HFC refrigerants and ester lubricants

A range of polyester motor insulation films is examined for compatibility with the ozone benign hydrofluorocarbon (HFC) refrigerants HFC 32, HFC 134a and HFC 125 and with mixed acid polyester lubricants. The results indicate that the HFC 134a-ester lubricant mixture is considerably more aggressive in terms of oligomer extraction to standard polyethylene terephthalate (PET) film than the chlorofluorocarbon (CFC) 12-mineral oil or HCFC 22-mineral oil standard refrigerant-lubricant mixtures. However, long oligomer PET film shows similar behavior in CFC 12, HCFC 22 or HFC 134a based refrigerant-lubricant systems.