Hydrolytically stable hydraulic lubricant
Lubricant compositions may provide corrosion resistance, oxidation resistance, and reduced wear for hydraulic systems. A lubricant composition may comprise an ashless dithiophosphate in an amount sufficient to provide a concentration of phosphorus ranging from 10 ppm to 250 ppm to the lubricant composition, a metal dialkyl dithiophosphate such as zinc dialkyl dithiophosphate (ZDDP) in an amount sufficient to provide a concentration of phosphorus ranging from 50 ppm to 1000 ppm to the lubricant composition, a corrosion inhibitor comprising an alkyltriazole derivative in an amount sufficient to provide a concentration of nitrogen ranging from 0.75 ppm to 100 ppm to the lubricant composition, and a major amount of a base oil.
1 . A lubricant composition comprising:
an ashless dithiophosphate;
a metal dialkyl dithiophosphate;
a corrosion inhibitor comprising an alkyltriazole derivative in an amount sufficient to provide a concentration of nitrogen ranging from 0.75 ppm to 100 ppm to the lubricant composition;
a major amount of a base oil; and
wherein the corrosion inhibitor is substantially free of benzotriazole and benzotriazole derivatives and substantially free of tolyltriazole and tolyltriazole derivatives.
2 . The lubricant composition of claim 1 , wherein the ashless dithiophosphate comprises 3-[[bis(2-methylpropoxy)phosphinothioyl]thio]-2-methyl-propanoic acid, ethyl 3-[[bis(1-methylethoxy)phosphinothioyl]thio]propionate, or a combination thereof.
3 . The lubricant composition of claim 1 , wherein the ashless dithiophosphate is present in an amount sufficient to provide a concentration of phosphorus ranging from 10 ppm to 40 ppm to the lubricant composition.
4 . The lubricant composition of claim 1 , wherein the metal dialkyl dithiophosphate comprises a primary zinc dialkyl dithiophosphate (ZDDP), a secondary ZDDP, or a combination thereof.
5 . The lubricant composition of claim 1 , wherein the metal dialkyl dithiophosphate is present in an amount sufficient to provide a concentration of phosphorus ranging from 50 ppm to 300 ppm to the lubricant composition.
6 . The lubricant composition of claim 1 , wherein the corrosion inhibitor comprises 1H-1,2,4-Triazole-1-methanamine, N,N-bis(2-ethylhexyl).
7 . The lubricant composition of claim 1 , wherein the corrosion inhibitor is present in an amount sufficient to provide a concentration of nitrogen ranging from 0.75 ppm to 15 ppm to the lubricant composition.
8 . The lubricant composition of claim 1 , wherein the composition has a copper weight loss in the hydrolytic stability test of 0.2 mg/cm 2 or less as measured according to ASTM D2619-21 over 96 hours.
9 . The lubricant composition of claim 1 , wherein the composition has a Rotating Pressure Vessel Oxidation Test (RPVOT) value of at least 350 mins as measured according to ASTM D2272-22.
10 . The lubricant composition of claim 1 , wherein the composition has a 4-ball wear value of less than 0.60 mm as measured according to ASTM D4172-21.
11 . The lubricant composition of claim 1 , further comprising a dispersant, a detergent, a friction modifier, or combinations thereof.
12 . A hydraulic system comprising the lubricant composition of claim 1 .
13 . A method for lubricating a hydraulic component comprising lubricating the component with the lubricant composition according to claim 1 .
14 . The method of claim 13 , wherein the hydraulic component is used in a vehicular application, a mobile application, or an industrial application.
15 . The method of claim 14 , wherein the mobile application comprises construction equipment.
16 . The method of claim 15 , wherein the construction equipment comprises wheel loaders, excavators, backhoes, bulldozers, graders, skid steers, articulated trucks, compact track loaders, or compactors.
17 . The method of claim 14 , wherein the industrial application comprises off-shore oil and gas, cement manufacturing, off-road, assembly plant, sub-sea hydraulics, pulp and paper, glass, dockyards, food processing, marine, power generation, rubber and plastics, or metal manufacturing.
18 . A method of making a lubricant composition comprising:
combining an ashless dithiophosphate, a metal dialkyl dithiophosphate, a corrosion inhibitor comprising an alkyltriazole derivative, and a major amount of a base oil to produce the lubricant composition of claim 1 .