Hydraulic Fluid Compositions and Preparation Thereof

Abstract

A hydraulic fluid composition having excellent oxidation stability prepared from an isomerized base oil is provided. The composition comprising (i) 80 to 99.999 wt. % of a lubricating base oil having consecutive numbers of carbon atoms, less than 10 wt % naphthenic carbon by n-d-M; and (ii) 0.001-20 wt % of at least an additive package. The hydraulic fluid composition meets the performance specifications of at least one of the JCMAS HK and JCMAS HKB standard specifications issued by the Fuels and Lubricants Technical Committee of Japan Construction Mechanization Association (JCMA).

1 . A hydraulic fluid composition comprising (i) 80 to 99.999 wt. % of a lubricating base oil; and (ii) 0.001-20 wt % of at least an additive package; wherein 
 the lubricating base oil has consecutive numbers of carbon atoms, less than 10 wt % naphthenic carbon by n-d-M, less than 0.10 wt. % olefins and less than 0.05 wt. % aromatics, a wt % total molecules with cycloparaffinic functionality greater than 25 and a ratio of molecules with monocycloparaffinic functionality to molecules with multicyloparaffinic functionality greater than 10; and    wherein the hydraulic fluid composition meets at least one of JCMAS HK and JCMAS HKB 2005 standard specifications.    
   
   
       2 . The hydraulic fluid composition of  claim 1 , having a viscosity index (VI) of at least 140.  
   
   
       3 . The hydraulic fluid composition of  claim 1 , having a VI of at least 160.  
   
   
       4 . The hydraulic fluid composition of  claim 1 , having a flash point of at least 270° C.  
   
   
       5 . The hydraulic fluid composition of  claim 1 , having an air release by ASTM D 3427-06 of less than 0.8 minutes at 50 degrees C., and a sequence II foam tendency by ASTM D 892-03 of less than 50 ml.  
   
   
       6 . The hydraulic fluid composition of  claim 1 , having a kinematic viscosity variation of less than 5% over a period of 1000 hours in a JCMAS HK test.  
   
   
       7 . The hydraulic fluid composition of  claim 6 , having a kinematic viscosity variation of less than 2.5% over a period of 1000 hrs in a JCMAS HK test.  
   
   
       8 . The hydraulic fluid composition of  claim 6 , having a RPVOT as measured according to ASTM D2272-02 of greater than 600 minutes.  
   
   
       9 . The hydraulic fluid composition of  claim 8 , having a RPVOT as measured according to ASTM D2272-02 of greater than 1000 minutes.  
   
   
       10 . The hydraulic fluid composition of  claim 1 , having a kinematic viscosity at 40° C. from 10 to 800 mm 2 /s.  
   
   
       11 . The hydraulic fluid composition of  claim 1 , wherein the lubricating base oil has a molecular weight of 500-750.  
   
   
       12 . The hydraulic fluid composition of  claim 7 , wherein the lubricating base oil has a molecular weight of greater than 600.  
   
   
       13 . The hydraulic fluid composition of  claim 1 , wherein the lubricating base oil has an auto-ignition temperature of at least 360° C.  
   
   
       14 . The hydraulic fluid composition of  claim 1 , wherein the lubricating base oil has an OECD 301D biodegrability of >=60%.  
   
   
       15 . The hydraulic fluid composition of  claim 1 , wherein the lubricating base oil comprises at least a Fischer-Tropsch base oil and 5 to 50 wt. % of at least a lubricant base oil selected from vegetable oils and Group I, II, III, IV, and V lubricant base oils as defined in the API Interchange Guidelines, and mixtures thereof.  
   
   
       16 . The hydraulic fluid composition of  claim 1 , wherein the lubricating base oil has a kinematic viscosity at 100° C. in the range of 1 and 15 mm2/s and a Noack volatility less than an amount defined by the equation: 900×(kinematic viscosity at 100° C.) −2.8 −15.  
   
   
       17 . The hydraulic fluid composition of  claim 1 , wherein the lubricating base oil has an average molecular weight between 600 and 1100, and an average degree of branching in the molecules between 6.5 and 10 alkyl branches per 100 carbon atoms.  
   
   
       18 . The hydraulic fluid composition of  claim 1 , wherein the lubricating base oil has an auto-ignition temperature in ° C. (AIT) greater than an AIT in ° C. defined by: 1.6×(kinematic viscosity at 40° C., in mm2/s)+300.  
   
   
       19 . The hydraulic fluid composition of  claim 1 , wherein the lubricating base oil has a traction coefficient less than an amount calculated by: 0.009×Ln (kinematic viscosity in mm2/s)−0.001, wherein the kinematic viscosity is the viscosity of the oil during the measurement of the traction coefficient.  
   
   
       20 . The hydraulic fluid composition of  claim 1 , wherein the hydraulic fluid composition further comprises at least one of: Pour Point Reducing Blend Components; polymethacrylates; polyacrylates; polyacrylamides; condensation products of haloparaffin waxes and aromatic compounds; vinyl carboxylate polymers; terpolymers of dialkylfumarates, vinyl esters of fatty acids, and alkyl vinyl ethers; and mixtures thereof.  
   
   
       21 . The hydraulic fluid composition of  claim 21 , wherein the hydraulic fluid composition further comprises a Pour Point Reducing Blend Component having an average degree of branching within a range of 6.5 to 10 alkyl branches per 100 carbon atoms.  
   
   
       22 . The hydraulic fluid composition of  claim 1 , wherein the lubricating base oil is a Fischer-Tropsch base oil having 0.001 to 0.05 wt. % aromatics and a molecular weight of greater than 600 by ASTM D 2503-92 (Reapproved 2002).  
   
   
       23 . The hydraulic fluid composition of  claim 1 , wherein the lubricating base oil comprises Fischer-Tropsch base oil having a kinematic viscosity at 100° C. between 6 mm 2 /s and 20 mm 2 /S; a kinematic viscosity at 40° C. between 30 mm 2 /s and 120 mm 2 /s; a viscosity index between 150 and 165; cold crank viscosity in the range of 3,000-50,000 mPa·s at −30° C., 2,000-20,000 mPa·s at −25° C.; pour point in the range of −2 and −20° C.; molecular weight of 500-750; density in the range of 0.820 to 0.840; paraffinic carbon in the range of 92-95%; naphthenic carbon in the range of 5-8%; Oxidator BN of 30 to 50 hours; and Noack volatility in wt. % of 0.50 to 5.  
   
   
       24 . A method for operating a hydraulic pump, the method comprising using a hydraulic fluid composition comprising (i) 80 to 99.999 wt. % of a lubricating base oil; and (ii) 0.001-20 wt % of at least an additive package; wherein the lubricating base oil has consecutive numbers of carbon atoms, less than 10 wt % naphthenic carbon by n-d-M, less than 0.10 wt. % olefins and less than 0.05 wt. % aromatics, a wt % total molecules with cycloparaffinic functionality greater than 25 and a ratio of molecules with monocycloparaffinic functionality to molecules with multicyloparaffinic functionality greater than 10; and wherein the hydraulic fluid composition meets at least one of JCMAS HK and JCMAS HKB 2005 standard specifications.