FREEZER OIL FOR CARBON DIOXIDE-REFREGERANT AND FLUID COMPOSITION FOR FREEZER

摘要

PROBLEM TO BE SOLVED: To provide a freezer oil for a carbon dioxide-refregerant having a sufficiently high fluidity, lubricating property and stability at a low temperature and also a sufficiently wide compatible area toward a carbon dioxide cooling medium, and a fluid composition for the freezer by using the same oil. SOLUTION: This freezer oil for the carbon dioxide-refregerant is characterized by containing a polyalkylene glycol expressed by the following general formula (1): R1 -(OR3)n-OR2} (1) [wherein, R1 is a residue obtained by removing m hydroxyl groups from an organic compound having 3-10 hydroxyl groups; R2 is H, a 1-5C alkylene or a 1-5C acyl; R3 is a 2-4C alkylene; (m) is 3-10 integer; (n) is an integer so as to make 500-3000 number-average molecular weight of the polyalkylene glycol (1)] and also having 5-20 mm2/s dynamic viscosity at 100 deg.C.