Water-glycol hydraulic fluid compositions
View Patent ↗A morpholine-free water-hydraulic liquid composition includes water, a glycol, a polyglycol such as a polyalkylene glycol, an aliphatic carboxylic acid that contains from six to 14 carbon atoms, and a combination of amines and alkanolamines.
1. A morpholine-free water-hydraulic liquid composition, consisting of:
water, a glycol, a polyglycol, decanoic acid, a combination of amines and alkanolamines, and optionally a primary alkanolamine selected from the group consisting of monoethanolamine, 2-amino-1,3-propanediol, 2-amino-2-methyl-1,3-propanediol, 2-amino-2-ethyl-1,3-propanediol, tris(hydroxymethyl)-aminomethane and 2-amino-1-butanol,
wherein the combination of amines and alkanolamines comprises 2-amino-2-methyl-1-propanol, N,N-dimethylethanolamine, and N,N-diethylethanolamine, wherein the composition has a pH equal to or greater than 9, and wherein the composition yields a total weight loss of ring and vanes in a modified Vickers Vane V104C pump test of less than 20 milligrams per 100 hours as measured in accord with ASTM D-7043 modified by using a one gallon reservoir, rather than a five gallon reservoir according to ASTM D-7043, stripping the pump subsequent to each test run and cleaning the stripped parts and rebuilding the pump, and conducting wear testing at a pressure of 2000 psig (14 MPa), a rotary speed of 1200 revolutions per minute (rpm), a bulk fluid temperature of 65° C. and a test duration of 100 hours, and wherein the composition has an initial reserve alkalinity from 145 milliliters to 200 milliliters,
and
wherein the polyglycol is a random copolymer of ethylene oxide and propylene oxide with an ethylene oxide content within a range of from 50 weight-percent to 90 weight-percent and a complementary content of propylene oxide within a range of from 10 weight-percent to 50 weight-percent in each case based upon total weight of ethylene oxide and propylene oxide, with complimentary amount of propylene oxide, when added to amount of ethylene oxide, equaling 100 percent by weight and wherein the composition has a water content from 30 to 54 percent by weight based upon total composition weight and wherein the composition has a polymer content from 10 to 20 percent by weight based upon total composition weight; and wherein the composition has from 0.5 to 1 percent by weight of 2-amino-2-methyl-1-propanol, from 0.1 to 2 percent by weight combined N,N-dimethylethanolamine, and N,N-diethylethanolamine; and from 0.5 to 2.5 percent by weight decanoic acid, all based upon total composition weight.
2. The composition of claim 1 wherein the decanoic acid is present in an amount sufficient to form an equilibrium acid-base salt complex with at least one amine.
3. The composition of claim 1 , wherein the primary alkanolamine is at least one of monoethanolamine and 2-amino-1-butanol.
4. The composition of claim 1 wherein the glycol is selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, a “bottom glycols” fraction produced during manufacture of diethylene glycol, and butylene glycol, and the alkylene glycol is present in an amount within a range of from 30 percent by weight to 50 percent by weight, based upon total weight composition.
5. The composition of claim 1 wherein the polyglycol is prepared from a random mixed feed of ethylene oxide and propylene oxide onto an initiator selected from glycerol, pentaerythritol, trimethylolpropane or diethylene glycol.