Synergistic polyether thickeners for water-based hydraulic fluids

A hydraulic fluid or metalworking fluid concentrate capable of imparting to water the properties of a lubricant such as resistance to extreme pressure and corrosion inhibition, said concentrate consisting essentially of:

• A. a water-soluble polyoxyethylated aliphatic ester consisting of esters of ethoxylated aliphatic monohydric and polyhydric alcohols and ethoxylated aliphatic acids wherein at least one of said acids or alcohols have about 5 to about 20 moles of ethylene oxide added per mole of acid or alcohol and wherein said alcohols and acids have carbon chain lengths of 8 to 36 carbon atoms and wherein said esters are produced by first polyoxyethylating at least one of said acids or alcohols and second, obtaining the ester reaction product thereof,
• B. a sulfurized metallic compound of the formula:
• ##STR3## wherein M is molybdenum or antimony and wherein R is selected from the group consisting of alkyl, aryl, alkylaryl radicals and mixtures thereof having 3 to 20 carbon atoms in the alkyl group and wherein the ratio of said water-soluble ester to said sulfurized metallic compound is from 5:1 to 2:1 by weight based upon the weight of the sulfur in said metallic compound,
• C. a phosphate ester salt selected from the group consisting of ##STR4## and mixtures thereof, wherein EO is ethylene oxide;
• R is selected from the group consisting of linear or branched chain alkyl groups having about 6 to 30 carbon atoms or alkylaryl groups wherein said alkyl groups have 6 to 30 carbon atoms;
• X is selected from the residue of ammonia, an amine and an alkali or alkaline earth metal or mixtures thereof, n is a number from 1 to 50 and wherein the proportion of said phosphate ester to said sulfurized metallic compound is about 0.1:1 to about 2:1 based upon the weight of the sulfur in said metallic compound,
• D. a polyether polyol thickener having a molecular weight of about 1000 to about 75,000, prepared by reacting ethylene oxide or ethylene oxide and at least one lower alkylene oxide having 3 to 4 carbon atoms with at least one active hydrogen-containing compound containing at least two active hydrogens and subsequently at least one alpha-olefin oxide having a carbon chain length of about 12 to about 18 aliphatic carbon atoms and wherein said alpha-olefin oxide is present in the amount of 1 to about 20 percent by weight based upon the total weight of said thickener, and optionally
• E. a corrosion inhibitor and a metal deactivator.