Patent ID: 7507348

Claim:
A refrigeration lubricant composition comprising an ester obtained from a mixed alcohol and a mixed carboxylic acid, wherein the mixed alcohol consists of 65 to 99.95 mol % of pentaerythritol and 0.05 to 35 mol % of dipentaerythritol, the mixed carboxylic acid consists of n-pentanoic acid, n-heptanoic acid, and isononanoic acid, the molar ratio of the n-pentanoic acid to the n-heptanoic acid is 0.3 or more and 10 or less, and the isononanoic acid is contained in the mixed carboxylic acid at a ratio of 10 mol % or more and less than 45 mol %, and wherein an average number of carbon atoms in a main chain of the mixed carboxylic acid that is calculated based on the molar ratio of the n-pentanoic acid, n-heptanoic acid isononanoic acid in the mixed carboxylic acid, and an average number of hydroxyl groups of the mixed alcohol that is calculated based on the molar ratio of the pentaerythritol and dipentaerythritol in the mixed alcohol satisfy the following relation: 1.2 ≤ Average ⁢ ⁢ number ⁢ ⁢ of ⁢ ⁢ carbon ⁢ ⁢ atoms ⁢ ⁢ in ⁢ ⁢ a ⁢ ⁢ main ⁢ ⁢ chain of ⁢ ⁢ the ⁢ ⁢ mixed ⁢ ⁢ carboxylic ⁢ ⁢ acid Average ⁢ ⁢ number ⁢ ⁢ of ⁢ ⁢ hydroxyl ⁢ ⁢ groups of ⁢ ⁢ the ⁢ ⁢ mixed ⁢ ⁢ alcohol ≤ 1.5 .