Environmentally compatible hydraulic fluid

Abstract

Environmentally safe and compatible fluids that are useful as lubricants, and especially as hydraulic fluids, in mobile machinery are formulated to be non-contaminating when accidentally contacted with surrounding vegetation, and removable from vegetation by simply washing the vegetation with tap water. The fluids of the invention are polyalkylene glycol-based and having an ethylene oxide to propylene oxide ratio of from about 68:32 to about 78:22.

1 . An environmentally compatible lubrication and hydraulic fluid for machinery, comprising:
 a polyalkylene glycol base comprised of two polyalkylene glycols having different viscosities, which is characterized in that the ethylene oxide to propylene oxide ratio of the polyalkylene glycol component of the fluid is from between about 68:32 and 78:22 by weight, and polyethylene glycol in an amount by weight of between 22.0% and 45.0%.   
   
   
       2 . The environmentally compatible lubrication and hydraulic fluid of  claim 1  wherein one of the two polyalkylene glycols having different viscosities comprises a polyalkylene glycol having an EO:PO ratio of about 50:50 by weight with a viscosity of about 100 cst at 40°, in an amount of from about 40.0% to about 70.0%. 
   
   
       3 . The environmentally compatible lubrication and hydraulic fluid of  claim 2  wherein the one of said two polyalkylene glycols having different viscosities comprises a polyalkylene glycol having an EO:PO ratio of about 50:50 by weight with a viscosity of about 100 cst at 40°, in an amount of from about 51.0%. 
   
   
       4 . The environmentally compatible lubrication and hydraulic fluid of  claim 2  wherein one of said two polyalkylene glycols having different viscosities comprises a polyalkylene glycol having an EO:PO ratio of about 50:50 by weight with a viscosity of about 8 cst at 40° C. 
   
   
       5 . The environmentally compatible lubrication and hydraulic fluid of  claim 2  wherein the ethylene oxide to propylene oxide ratio of the polyalkylene glycol component of the fluid is about 72:28. 
   
   
       6 . The environmentally compatible lubrication and hydraulic fluid of  claim 2  further comprising at least one surfactant. 
   
   
       7 . The environmentally compatible lubrication and hydraulic fluid of  claim 6  further comprising a surfactant in an amount of from about at 2% to about 3.5%. 
   
   
       8 . The environmentally compatible lubrication and hydraulic fluid of  claim 6  wherein said at least one surfactant is a polyoxypropylene, polyoxyethylene blocked copolymer. 
   
   
       9 . The environmentally compatible lubrication and hydraulic fluid of  claim 6  wherein said surfactant is selected from the group consisting of non-ionic, anionic, cationic and amphoteric surfactants, and mixtures thereof. 
   
   
       10 . The environmentally compatible lubrication and hydraulic fluid of  claim 1  further comprising at least one antioxidant, anti-corrosive or EP/AW additive, or combinations thereof. 
   
   
       11 . The environmentally compatible lubrication and hydraulic fluid of  claim 10  wherein said fluid contains an EP/AW additive comprising amyl acid phosphate. 
   
   
       12 . A method of producing an environmentally compatible lubrication and hydraulic fluid for machinery, the method comprising:
 combining a first base fluid comprising a polyalkylene glycol having an EO:PO ratio of about 50:50 by weight and a viscosity of about 100 cst at 40° C. and a second base fluid comprising a polyalkylene glycol having a EO:PO ratio of about 50:50 by weight and a viscosity of about 8 cst at 40° C.; and   adding a third base fluid comprising PEG of about 100% EO to reach a desired final EO:PO ratio of between about 68:32 to about 78:22 by weight.   
   
   
       13 . The method according to  claim 12 , wherein combining a first base fluid comprising a polyalkylene glycol having an EO:PO ratio of about 50:50 by weight and a viscosity of about 100 cst at 40° C. with a second base fluid comprising a polyalkylene glycol having a EO:PO ratio of about 50:50 by weight and a viscosity of about 8 cst at 40 comprises adding the first base fluid in an amount of from about 40 to about 70 percent by weight of the final fluid. 
   
   
       14 . The method according to  claim 13 , wherein adding the first base fluid an amount of from about 51 percent by weight of the final fluid. 
   
   
       15 . The method according to  claim 12 , wherein adding a third base fluid comprising PEG of about 100% EO to reach a desired final EO:PO ratio of between about 68:32 to about 78:22 by weight comprises adding the third base fluid to reach a desired final EO:PO ratio of about 72:28 by weight. 
   
   
       16 . The method according to  claim 12 , wherein the first base fluid, the second base fluid and the third base fluid are mixed by adding the three base fluids together and stirring until a homogeneous fluid is achieved. 
   
   
       17 . The method according to  claim 16 , further comprising heating the resulting mixture to a maximum temperature of 50° C. for about 30-60 minutes to dissolve any any solids into solution. 
   
   
       18 . The method according to  claim 12 , further comprising adding at least one surfactant comprising a polyoxypropylene, or polyoxyethylene blocked copolymer. 
   
   
       19 . The method according to  claim 12 , further comprising adding at least one surfactant is selected from the group consisting of non-ionic, anionic, cationic and amphoteric surfactants, and mixtures thereof. 
   
   
       20 . The method according to  claim 12 , further comprising adding at least one antioxidant, anti-corrosive or EP/AW additive, or combinations thereof.