| abstract |
At temperatures above 200 °C, polyoxyalkylene glycol lubricants decompose to form water and other products. This is undesirable in refrigeration and air-conditioning systems because the presence of water causes corrosion of metallic parts in the system, freezes out and blocks expansion valves upon refrigerant cooling, and reacts with poly(ethylene terephthalate) films which insulate electric motor parts in hermetic systems so that eventually the film is destroyed and the water contacts the electric motor parts. The present invention provides a stabilized composition which substantially reduces the decomposition of polyoxyalkylene glycols. The stabilized polyoxyalkylene glycols comprise: (a) polyoxyalkylene glycol and (b) a composition comprising: (i) at least one component selected from the group consisting of phenol and trivalent phosphorus compound and (ii) at least one epoxide selected from the group consisting of aromatic epoxide and fluorinated alkyl epoxide. |