Lubricant composition

Abstract

An object is to provide a lubricant oil composition excellent in biodegradability, lubricating property (extreme pressure property), stability against oxidation and demulsibility, having low toxicity and bioaccumulation property in an aquatic life, and excellent in stability against shearing even in the presence of water.A lubricant oil composition comprises 100 mass parts of the following ester compound (A), 0.1 to 1.5 mass parts of the following amine salt (B) of an acidic phosphoric acid ester, 0.3 to 2.0 mass parts of an amine-based oxidation preventing agent (C), and 0.3 to 2.0 mass parts of a phenol-based oxidation preventing agent (D),(A) the ester compound comprising a molar percentage of 20 to 30 mol % of a constituent component (a) derived from pentaerythritol, a molar percentage of 55 to 79 mol % of a constituent component (b) derived from a straight-chain fatty acid having a carbon number of 14 to 22, and a molar percentage of 1 to 15 mol % of a constituent component (c) derived from adipic acid, wherein a ratio [(c) mol %/(b) mol %] of the molar percentage of the constituent component (b) with respect to the molar percentage of the constituent component (c) is 0.02 to 0.25 and wherein the ester compound has a hydroxyl value of 10 to 100 mgKOH/g,(B) the amine salt of an acidic phosphoric acid ester represented by the following formula (1),(in the formula (1), n represents an integer of 1 or 2, R′ represents a straight-chain alkyl group having a carbon number of 4 to 6, and R″ represents hydrogen or an alkyl group having a carbon number of 11 to 14.).

1 . A lubricant oil composition comprising 100 mass parts of the following ester compound (A), 0.1 to 1.5 mass parts of the following amine salt (B) of an acidic phosphoric acid ester, 0.3 to 2.0 mass parts of an amine-based oxidation preventing agent (C), and 0.3 to 2.0 mass parts of a phenol-based oxidation preventing agent (D),
 (A) said ester compound comprising a molar percentage of 20 to 30 mol % of a constituent component (a) derived from pentaerythritol, a molar percentage of 55 to 79 mol % of a constituent component (b) derived from a straight-chain fatty acid having a carbon number of 14 to 22, and a molar percentage of 1 to 15 mol % of a constituent component (c) derived from adipic acid, wherein a ratio [(c) mol %/(b) mol %] of said molar percentage of said constituent component (b) derived from said straight-chain fatty acid with respect to said molar percentage of said constituent component (c) derived from adipic acid is 0.02 to 0.25 and wherein said ester compound has a hydroxyl value of 10 to 100 mgKOH/g,   (B) said amine salt of an acidic phosphoric acid ester represented by the following formula (1),   
       
         
           
           
               
               
           
         
         (in the formula (1),
 n represents an integer of 1 or 2, 
 R′ represents a straight-chain alkyl group having a carbon number of 4 to 6, and 
 R″ represents hydrogen or an alkyl group having a carbon number of 11 to 14.).