LUBRICANT COMPOSITION FOR REFRIGERATION COMPRESSOR CAPABLE OF SUPPRESSING NOISE OF THE REFRIGERATION COMPRESSOR

摘要

PROBLEM TO BE SOLVED: To obtain a subject lubricant composition capable of suppressing generation of an abnormal noise caused by an irregularity of foam cells formed while operating a compressor by blending a specific foaming agent with a lubricant oil composition for refrigeration compressor containing hydrofluorocarbon-based refrigerating medium and containing no chloride. SOLUTION: The subject lubricant is obtained by blending (E) 0.001-0.01wt.% silicone-based oil preferably dimethylpolysiloxane of the formula [(n) is 2-4,000]} as a foaming agent with a lubricant composition for refrigeration compressor comprising (A) hydrofluorocarbon-based refrigeration medium containing no chloride (preferably 1,1,1,2-tetrafluoroethane), (B) an ester oil having two or more ester bonds as a lubricant, (C) a hydrolytic stabilizer and (D) an oxidation stabilizer. The component B is preferably the one obtained by performing an esterifying reaction of a 2-10C branched fatty acid with a polyfunctional alcohol such as neopentyl glycol. Generally, an epoxy-base stabilizer is used as the component C and di-tert-butyl-p-cresol is used as the component D.