| 摘要 |
PROBLEM TO BE SOLVED: To obtain the subject hydraulic fluid composition that is resistant to occurrence of sludge caused by the decomposition of zinc dithiophosphate even after use for a long time by using the base oil, zinc dithiophosphate, an alkyl or alkenyl phosphate in specific amounts. SOLUTION: This hydraulic fluid composition comprises (A) the base oil, for example, hydraulic fluid or the like, (B) 0.1-5 wt.%, based on the total weight of the composition, of zinc dithiophosphate, (C) 0.1-5 wt.% of a compound selected from (i) an alkyl or alkenyl phosphate, (for example, isodecyl acid phosphate or the like) or its amine salt, (ii) a condensate between a polyethylene- polyamine (for example, tetraethylenepentamine or the like) and a fatty acid (for example, isostearic acid or the like), and (iii) a condensate between a dialkanolamine (diethanolamine or the like) and a fatty acid (for example, oleic acid). In a preferred embodiment, a metallic detergent, an ash-free dispersant, an antioxidant and other known additives may be admixed in amounts of 0.05-25 wt.% based on the whole amount of the composition. |
