water glycol hydraulic pump free sample

Industrial fluid power applications have increased worldwide over the years. Hydraulic fluid performance demands have increased in operating pressures, safety and reliability. As operating pressures increase, the risk of fire from ruptured lines also increases. It is necessary to balance management’s regulatory and insurance interests with equipment requirements for effective lubrication, wear and corrosion protection.

Fire-resistant fluids include synthetics such as phosphate esters or ester-mineral blends and water-based formulas such as water-oil emulsions or water-glycols. Water glycol fluids have proven to be an excellent fire-resistant hydraulic fluid option.

The fire-resistance of these fluids depends upon the vaporization of the water and the smothering effect of the steam. The other performance characteristics important to these fluids are viscosity, lubrication quality, operating temperature range, corrosion resistance, system compatibility and fluid maintenance. Excellent fire-resistance coupled with good cost and performance makes water glycol fluids the right choice for many industrial applications.

Water glycol fluids consist of a solution of water, ethylene or diethylene glycol, a high molecular weight polyglycol and an additive package. The water-to-glycol mixture typically contains 38 to 45 percent water. These fluids usually contain red or pink dye to aid in their identification.

With water in the fluids’ formulation, evaporation is ongoing and upper operating temperature limits must be considered. Checks must be made periodically of the water content. The fluids’ typical operating temperatures should be kept below 150°F.

The polyglycol is a water-soluble polymer thickener, which can be formulated to cover a wide range of viscosities. The resulting viscosity-temperature properties are Newtonian and give water glycols good low-temperature cold-start pump wear protection as well as minimizing cavitation.

The additive package imparts corrosion resistance, metal passivation, seal and hose compatibility, oxidation resistance, antimicrobial properties and antiwear properties. With a density of about 1.0, mineral oil contaminants may float on the fluid surface and be skimmed off. Finally, water glycol fluids have better thermal transfer properties over other fire-resistant fluids.

Water glycol fluids usually have an operating range up to 2000 psi at less than 150°F. Their lubricating quality is very good where loads are moderate and where only hydrodynamic lubrication is involved. When the application has high bearing loads and extreme boundary lubrication conditions, higher wear rates should be expected. Typical applications include:

There are some application limitations due to compatibility when using water glycol fluids. Regarding metals, the fluid is corrosive to zinc, cadmium and nonanodized aluminum, and the reaction with these metals causes rapid deterioration of the fluid.

Synthetic rubber seal and gasket compatibility is good, however polyurethane, leather or cork materials should be avoided. Typical paints will soften in the presence of water glycols; therefore painted surfaces should be painted with epoxy resin paints.

Testing should be conducted initially to measure the water glycol fluid’s ability to meet performance specifications. When charged to a system and during use, water glycol should be periodically tested as part of a maintenance condition-monitoring program.

Given that fluid performance results may differ significantly, as shown in Table 2, fluid performance based on standardized (ASTM) tests should have a major influence in product selection. A Midwestern steel plant recently requested five major commercially available water glycol fluids be evaluated for lubrication performance. Table 2 shows that significant variation is possible. The fifth fluid is unqualified for use.

Note the apparent lack of correlation in Table 2 between the vane pump test (combination boundary and hydrodynamic lubrication) and the boundary lubrication measurement of the Four-ball Wear Test. Figure 1 shows the sample specimen for ASTM D2882 vane pump testing on fluids A (left) and E (right). Fluid E clearly shows the excessive metal scuffing and wear.

The most common fluid faults noted in samples tested from water glycol users are particle contamination, contamination with other fluids and water loss or accumulation shifting the viscosity.

Particle and dirt contamination is a problem for water glycols more than mineral oils because of the affinity of the polymers to hold the fine particles in suspension. Good maintenance practices and filter management is required.

Contamination from mineral oils is readily observable by visual appearance (pink milky emulsion sample) or FTIR. Figure 2 shows a used normal fluid and a used contaminated fluid. The milky appearance and the layer of mineral oil on the top of the sample fluid suggest an oil/water emulsion condition. Contamination often occurs due to the widespread use of mineral oils near or on the equipment using the water glycols, or as a result of direct contamination resulting from poor reservoir top-up practices.

Water loss due to evaporation or accumulation due to the intrusion of free water such as cooling water can be measured accurately by Karl Fischer titration or a refractometer. Make-up water must be distilled or deionized (DI), such as from boiler feed water condensate. Water concentrations should be maintained according to guidelines provided by the OEM. This may mean adding either glycol concentrate or DI water to systems during the lifecycle of the product. This is done to retain proper viscosity and fire-resistance properties.

Water glycols must not be mixed with nonwater-based hydraulic fluids and preferably not with other brands of water glycols. Additive packages in various brands may conflict, resulting in loss of fluid performance. The alkalinity reserve additive does deplete by evaporation. The manufacturer can help users manage fluid alkalinity by supplying supplemental additive.

Water glycol fire-resistant hydraulic fluids are a reliable, cost-effective option for hydraulic power. When maintained properly, they give long, predictable life.

Hydraulic fluid performance, including water-glycols (W/G), depends on the chemical composition of the fluid and cleanliness. This article presents an overview of the effect of W/G fluid chemistry on pump wear. An overview of recommended analytical procedures to assure adequate long-term hydraulic and lubrication performance is provided. These procedures can result in substantial improvements in hydraulic pump longevity and performance.

Many industrial applications such as steel making, die casting, etc. require the use of hydraulic fluids that offer greater fire safety than that achievable with mineral oil. One of the most common alternatives to mineral oil for use in these applications is a water-glycol hydraulic fluid.

The performance of all hydraulic fluids, including W/G hydraulic fluids, depends on the composition of the fluid and on fluid cleanliness. Although there are numerous references describing analysis procedures for petroleum oil-derived hydraulic fluid, similar references describing the analysis of water-glycol hydraulic fluid are relatively rare.

Water-glycol hydraulic fluid formulations typically contain water (for fire protection), glycol (for freeze point protection), polyalkylene glycol (PAG) thickener, an additive package to provide corrosion and antiwear protection, antifoam/air release additive and dye for leak detection.

The performance of a hydraulic fluid depends on the particular additive and concentration used in the formulation. Substances that exhibit a marked effect on hydraulic pump wear, according to the ASTM D2882 test, are water, amines and antiwear additives. The ASTM D2882 test is conducted at 2,000 psi (13.8 MPa) for 100 hours and eight gallons per minute (30.6 L/min) in a Sperry Vickers V-104C vane pump.

Water content creates one of the most significant influences on hydraulic pump wear rate. Figure 1 shows that wear rates increase with increasing water content. Thus, it is critically important to control the water content of W/G hydraulic fluids if both fire-resistance and antiwear performance is to be maintained.

The primary function of the amine is to provide corrosion protection. Vapor and liquid phase inhibitory properties of an amine can be determined using the 200-hour Corrosion Test. This test is conducted by aerating the heated hydraulic fluid at 70 ± 2°C in contact with metal test coupons for 200 hours. The test coupons that are immersed in the fluid are: steel (SAE-1010, low carbon), cast aluminum (SAE-329), copper (CA-110) and brass (SAE-70C). Vapor phase corrosion effects are also determined using coupons of cast iron (G-3500) and steel (SAE-1010) which are suspended above the solution. Figure 3 illustrates a typical corrosion test cell.

Figure 3. Corrosion Test Apparatus is Convenient for Corrosion-Inhibitor Studies of Water-Glycol Hydraulic Fluids Under Laboratory Conditions. Immersed Metal Specimens are Separated by a Glass “Z-bar” in the Specific Order Shown. Vapor-Space Test Specimens are Hung from the Top of the Glass Test Cell. Fluid Temperature is Monitored with an Immersion Thermometer, Air is Blown into the Mixture Using an Aeration Tube, and a Cold-Water Condenser is Used to Reduce Fluid by Evaporation.

Fortunately, as shown in Figure 4, it is possible to formulate a W/G hydraulic fluid so that there will be minimal impact on wear with the inevitable loss of additive over time. Nevertheless, once the critical level is achieved there is a dramatic increase in wear rates with further decreases in antiwear additive concentration.

Hydraulic pump lubrication depends not only on fluid chemistry but also on both liquid and solid contamination. In W/G fluids, the most common liquid contamination is usually petroleum oils, which may enter the hydraulic system from numerous sources. Because petroleum oils are insoluble in the W/G they may be simply skimmed from the fluid reservoir. In practice, removal is often neglected for long enough periods that some of the additives adsorb into the mineral oil and are removed from the working fluid when that oil is skimmed from the surface of the reservoir. Every effort should be made to prevent this form of contamination.

Water contained in a W/G fluid can be lost through evaporation during normal hydraulic operation. Water loss increases the fluid’s viscosity. Water must therefore be added back to the system to maintain fire-resistance and to assure proper viscosity and system operation.

The most common methods for determining water content of a W/G hydraulic fluid are refractive index, viscosity and Karl Fischer analysis. Refractive index is the most commonly used and is readily determined using a portable temperature-compensated refractometer that provides readings in degrees Brix.

The principal limitation of water determination by refractive index is that refractive index is affected by any material, including contaminants, that may be present in the hydraulic fluid. Thus, it is advisable to crosscheck water analyses obtained by refractive index against at least one other analytical method. After the water concentration is determined, additional water should be added if necessary. Some suppliers provide tables such as Table 1, which provide water make-up levels without the use of the calibration plot represented by Figure 5.

Only distilled or deionized water with a conductance of less than 15 µmhos/cm (or a maximum total water hardness of 5 ppm has also been recommended), should be added to a W/G hydraulic fluid system. This is critically important because polyvalent metal ions such as Ca+2, Mg+2, Mn+2, etc. will react with the antiwear additive, usually an organic carboxylic acid, to form a polyelectrolyte complex salt (Formula 1) which appears as a white, soapy solid. This process must be prevented for two reasons. The first is that it will lead to continuous depletion of the critically important antiwear additive. Second, the presence of such precipitates, like any solid material, will increase wear.

The water content of a hydraulic fluid may also be determined by viscosity measurement. One common method of viscosity measurement is to follow the ASTM D445 procedure for kinematic viscosity.

By using the chart in Figure 6, viscosity vs. water content, the amount of water can be easily maintained within the necessary range for the fluid. Alternatively, a water make-up table based on viscosity, as shown in Table 2, may be obtained from the W/G hydraulic fluid supplier for the specific fluid being used.

The load-bearing capacity of a fluid film depends on fluid viscosity. Oxidative and thermal degradation processes will result in a decrease of fluid viscosity. Thus routine viscosity measurement is one of the best methods of monitoring fluid stability. However, such comparative measurements must be made at the same total water content.

The third, and most unambiguous, method of water determination is by Karl Fischer Titration (ASTM D1744). The advantage of Karl Fischer analysis is that it is a direct measure of water content, while viscosity and refractive index are both indirect measurements which are substantially affected by either contamination (refractive index) or fluid degradation (viscosity).

Amine concentration in a W/G hydraulic fluid is designated as reserve alkalinity and is conventionally reported as the volume in milliliters of 0.1N hydrochloric acid (HCl) required to titrate 100 ml of W/G fluid to pH 5.5. A typical titration plot is shown in Figure 7.

Figure 8. Two-dimensional Contour Plot - Effect of Formic Acid and Reserve Alkalinity on ASTM D2882 Wear Rates of a Conventional W/G Hydraulic Fluid. Wear Rate is Affected by Both Formic Acid Content and Alkalinity.

It has thus far been shown that hydraulic fluid quality and performance depends on fluid cleanliness and chemistry variation. On occasion, it is necessary to troubleshoot fluid performance in malfunctioning systems. In addition to the chemical and physical analyses described, it is often valuable to analyze any wear debris. Ferrography is one of the principal wear debris analysis methods. It can be used to determine the concentration and distribution of wear particles contained in the hydraulic fluid.

It has been shown that W/G hydraulic fluid performance, like all other hydraulic fluids, depends on both fluid cleanliness and fluid formulation chemistry.

Water, antiwear additive and corrosion inhibitor concentrations must be monitored to assure optimum fluid antiwear performance. Recommended analytical methods include:

While analysis by ion chromatography and ferrography are specialized procedures and may be conducted as required, analysis for water content, reserve alkalinity, viscosity as well as visual observations are critical and must be conducted regularly (usually by the fluid supplier).

If the hydraulic system is properly maintained and fluid performance is adequately monitored, excellent long-life hydraulic and lubrication performance with water-glycol fluids is achievable.

Ciekurs, P. Ropar, S. and Kelley, V. "Prediction of Hydraulic Pump Failures Through Wear Debris Analysis." Naval Air Engineering Center Report, NAEC-92-171. July 19, 1983.

Castrol AnvolTM WG 46 is an HF-C type water-glycol fire-resistant hydraulic fluid, containing anti-wear additives and corrosion inhibitors. It provides excellent protection against rust and vapor phase corrosion. In hydraulic pump tests, Anvol WG 46 has shown high levels of anti-wear performance. Its foam resistance, low temperature flow, emulsion stability and storage stability are also excellent.

Anvol WG 46 is for use in hydraulic systems where, in the event of fluid leakage, there is a significant risk of ignition. Examples of applications include furnace doors, die-casting machines, forging machinery and mining equipment. It can be used in vane, gear or piston-type pumps with pressures up to 3000 PSI. As with any water containing fluid, continuous high temperature leads to excessive evaporation. The water content should be checked regularly in service and any corrections made by addition of distilled or de-ionized water. Occasional monitoring of alkalinity is recommended to ensure the correct level of corrosion inhibition. Care should be taken to ensure the hydraulic system is designed for using water glycol-based fluids. Care should also be taken to ensure the compatibility of Anvol WG 46 with paints, seals and metals, and also ensure that the hydraulic pumps and filters used are suitable. A thorough draining and flushing procedure should be followed when converting from other fluids to water glycol-based solutions. Anvol WG 46 is fully compatible with nitrile, neoprene, silicone, nylon, butyl rubber and fluropolymer seal materials. Anvol WG 46 meets the fire resistance requirements of: 7th Luxembourg Report FM Global 6930

This invention relates generally to water-glycol hydraulic fluid compositions and more particularly to such compositions that are substantially morpholine-free.

U.S. Pat. No. 4,855,070 to Lewis discloses a water-glycol energy transmitting fluid that comprises a) from 30 percent by weight (wt %) to 40 wt % water, b) diethylene glycol, c) from 0.8 wt % to 5.0 wt % of an aliphatic carboxylic acid having 9 to 12 carbon atoms (C9-C12) inclusive, d) a water-soluble polymeric viscosity control agent, e) a corrosion inhibiting amount of at least one corrosion inhibitor, and f) a metal deactivator, each wt % being based upon total fluid weight. Illustrative corrosion inhibitors include alkyl amines such as propylamine and dimethylaminopropylamine; alkanolamines such as monoethanolamine, N,N-dimethylethanolamine or an arylamine such as aminotoluene; another amine-type corrosion inhibitor such as ethylenediamine, morpholine or pyridine; or mixtures thereof. The metal deactivator functions as a chelating agent for copper and copper alloys. Illustrative water-soluble polymeric viscosity control agents include poly(alkylene oxide) polymers, alkylene oxide adducts of alkyl phenols, polyalkyl methacrylates, urethane polymers, polyamide esters, and polyamide alkoxylates, with poly(alkylene oxide) polymers being preferred.

Modern water/glycol hydraulic fluids constitute highly engineered products and comprise a complex mixture of components. Key components of such fluids, in addition to water and glycol, include a high molecular weight (e.g., a number average molecular weight of more than 6,000) polyglycol (also known as an “alkylene glycol”) as a thickener or water-soluble polymeric viscosity control agent, vapor phase corrosion inhibitors and solution corrosion inhibitors. Such fluids often contain one or more additives including an anti-wear additive that forms a surface film between moving metal parts in an apparatus such as a pump, especially during start-up activities for the pump. Vapor phase corrosion inhibitors typically provide a measure of protection for ferrous surfaces, such as steel and cast iron, both commonly found in alloys used to fabricate hydraulic equipment. Solution corrosion inhibitors inhibit corrosion of metals often used in hydraulic circuits including cast iron, stainless steel, aluminum, brass and copper. Hydraulic fluids that come in contact with a yellow metal, such as brass, typically contain an additive such as tolyltriazole for yellow metal passivation.

Water/glycol hydraulic fluids find use in automotive, steel and mining industrial applications that typically require reliable, preferably sustained, performance in operation of hydraulic equipment as well as a measure of fire resistance. Fire resistance takes on increasing importance in an environment where there is a significant risk of fire due to fluid leakage. Resistance to fire does not, however, mean complete freedom from fire as skilled artisans recognize that organic fluids, such as glycols, do burn when present in sufficient concentration and exposed to sufficient oxygen, heat and a flame source to ignite at least volatile components of such organic fluids.

A number of regional standards for fire resistance ratings of hydraulic fluids exist. For example, in North America, Factory Mutual certifies fluids according to fire resistance ratings in which the fluids are given a rating of “Product Specified” or “Product Approved”, with top tier fluids being certified with a “Product Approved” rating. In Europe, current legal requirements mandate sale of fire resistant fluids that have 7thLuxembourg accreditation, a combination of fire resistance and hydraulic wear performance. The latter standard appears to be gaining ground as a global norm for fire resistance ratings.

A general purpose water/glycol hydraulic fluid (sometimes referred to as a “hydrolube”) marketed by The Dow Chemical Company under the trade designation UCON™ Hydrolube DG-746 finds use in vane, gear and piston pump hydraulic equipment, all of which operate at a outlet pressure of up to 3500 pounds per square inch gauge (psig) (24 megapascals (MPa). Higher outlet pressures typically use an alternate hydrolube such as UCON™ Hydrolube HP-5046 which is recommended for hydraulic pumps operating at pressures up to 5000 psig (34 MPa). These hydrolubes are among many marketed by producers of hydrolubes that contain morpholine.

As industrial demands increase, particularly for hydraulic equipment that both has a size smaller than current hydraulic equipment and operates under a pressure in excess of 5000 psig (30 MPa), hydraulic equipment under construction or development, tends to have a smaller fluid reservoir size than hydraulic equipment in use in the 1990"s or even early 2000"s. A smaller fluid reservoir translates, in turn, to an increased number of times that a hydraulic fluid circulates around a hydraulic circuit within such equipment, thereby effectively exposing such fluid to a higher stress environment than that present in earlier hydraulic equipment. The higher stress environment usually includes higher bulk fluid temperatures than those experienced in such earlier hydraulic equipment. The higher stress environment can lead to one or more of viscosity loss, possibly because of shear instability at the higher pressures, degradation of the hydraulic fluid sufficient to produce degradation products such as thermo-oxidative degradation products that increase hydraulic equipment component wear rates relative to hydraulic fluids that lack such degradation products. Totten and Sun, in Handbook of Hydraulic Fluid Technology, (2000) note, at page 917, that degradation products such as formic acid have been shown to significantly increase hydraulic wear rates in water glycol hydraulic fluids at levels in excess of 0.15 percent by weight (wt %), based upon total weight of fluid. Smaller hydraulic equipment leads, in turn, to a requirement for hydraulic fluids that withstand operating in such a higher stress environment.

Legislation in certain countries, primarily those located in Europe, designates secondary amines, such as morpholine, as restricted materials because of a potential to form nitrosamines when in contact with sodium nitrite, a commonly used corrosion inhibitor in fluid and lubricant formulations. As such, compounds that contain morpholine (e.g. morpholine-containing fire resistant water/glycol hydraulic fluids) also fall in a class of restricted materials. Elimination of morpholine from fire resistant water/glycol hydraulic fluids should take such fluids out of the class of restricted materials.

An aspect of an invention embodied in appended claims is a substantially morpholine-free water-hydraulic liquid composition, the liquid composition comprising water, a glycol, a polyglycol, an aliphatic carboxylic acid that contains from six to 14 carbon atoms, and a combination of amines and alkanolamines.

Compositions of the present invention include an amount of polyglycol or alkylene glycol. The amount preferably lies within a range of from 30 percent by weight to 50 percent by weight, based upon total composition weight.

Illustrative alkylene glycols include those selected from a 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.

The alkylene glycol is preferably a polyalkylene glycol selected from a group consisting of random copolymers of ethylene oxide and propylene oxide, more preferably a random copolymer of ethylene oxide and propylene oxide with an ethylene oxide content within a range of from 50 wt % to 90 wt % and a complementary propylene oxide content within a range of from 10 wt % to 50 wt %, in each case based upon total weight of ethylene oxide and propylene oxide, with complementary amount of propylene oxide, when added to amount of ethylene oxide, equalling 100 percent by weight. The random copolymer of ethylene oxide and propylene oxide more preferably has an ethylene oxide content within a range of from 70 wt % to 80 wt %, with a complementary propylene oxide content within a range of from 20 wt % to 30 wt %. The random copolymer of ethylene oxide and propylene oxide still more preferably has an ethylene oxide content within a range of from about 74 wt % to 76 wt %, with complementary propylene oxide content within a range of from 26 wt % to 24 wt %. The random copolymer of ethylene oxide and propylene most preferably has an ethylene oxide content of about 75 wt % and a complementary propylene oxide content of about 25 wt %.

The polyglycols used in water-liquid compositions of the present invention function as a viscosity modifier or thickening agent and have a number average molecular weight that is preferably within a range of from 6,000 to 40,000, more preferably within a range of from 8,000 to 30,000, and still more preferably within a range of from about 10,000 to 25,000. Skilled artisans understand that a viscosity modifier increases composition viscosity, or thickens it, relative to an identical composition save for absence of the viscosity modifier. Without a viscosity modifier, composition viscosity of a water-glycol hydraulic fluid may be low enough to lead to problems such as excess apparatus (e.g. pump) wear or fluid leakage through or past apparatus seals.

In preparing such polyglycols, react a random mixed feed of ethylene oxide and propylene oxide onto an initiator such as glycerol, pentaerythritol, trimethylolpropane or diethylene glycol. Paul Matlock and William R. Brown describe such preparation in a chapter devoted to polyalkylene glycols in Synthetic Lubricants& High Performance Functional Fluids, (1993), chapter 4, p. 101-123, edited by Ronald Shubkin.

Substantially morpholine-free water-hydraulic liquid compositions of the present invention include water to promote fire resistance, diethylene glycol for low temperature control, a short chain (six to fourteen carbon atoms (C6to C14)) aliphatic carboxylic acid such as decanoic acid (sometimes referred to as “capric acid”) or nonanoic acid (sometimes known as perlagonic acid) as an anti-wear component for pump start and boundary lubrication, tolyltriazole for yellow metal passivation and polyalkylene glycol as a high molecular weight viscosity modifier for hydrodynamic lubrication.

The aliphatic carboxylic acid is present in an amount sufficient to form an equilibrium acid-base salt complex with at least one amine. By way of illustration, when the aliphatic carboxylic acid is decanoic acid, the amount is preferably within a range of from 0.5 percent by weight (wt %) to 2.5 wt %, based upon total water-hydraulic liquid composition weight.

By way of illustration, but not by limitation, preparation of substantially morpholine-free, preferably completely morpholine-free, water-hydraulic liquid compositions of the present invention suitably involves mixing or stirring together a combination of water, glycol (e.g. diethylene glycol), primary amine and tertiary amine (also referred to herein as “alkanolamine”) at, for example, ambient temperature (nominally 25° C.). Stirring at this temperature preferably continues until the combination appears as a visually clear, homogeneous solution. Add the aliphatic carboxylic acid with continued stirring, preferably until the solution once again appears as a visually clear, homogeneous solution. If one chooses to add a yellow metal passivator such as tolyl triazole, add it next with stirring to facilitate dissolution of the yellow metal passivator. Mild (up to 50° C.) heating may enhance dissolution of the yellow metal passivator. Following dissolution of the yellow metal passivator, or following addition of the aliphatic carboxylic acid if one omits a yellow metal passivator, add a polyglycol or polymeric thickening agent with continued stirring until the solution once again takes on appearance as a visually clear, homogeneous solution.

The illustrative preparation of water-hydraulic liquid compositions of the present invention employs “mild” temperatures of no more than 50° C. While higher temperatures may be used if desired, such higher temperatures need not be employed. One should, however, avoid temperatures in excess of 160° C. to substantially preclude formation of amides. Amides are neither needed nor desired in compositions of the present invention.

The substantially morpholine-free water-hydraulic liquid compositions of the present invention preferably yield a total weight loss of ring and vanes in a Vickers Vane V104C pump test of less than 100 milligrams as measured in accord with ASTM D7043 as described below. The total weight loss is preferably less than 50 milligrams.

The substantially morpholine-free water-hydraulic liquid compositions of the present invention have a water content that is greater than 0 wt %, preferably greater than 40 wt %, more preferably more than 44 wt %, in each case based upon total composition weight. The amount of water is preferably less than that which leads to a total ring and vane weight loss more than 100 milligrams, more preferably but no more than 54% by weight, based upon total composition weight.

Measure corrosion performance of a water/glycol hydraulic solution, both solution phase and vapour phase, using a modification of American Standard for Testing and Materials (ASTM) G31-72. Immerse steel, cast iron, copper, brass and aluminium coupons in the hydraulic fluid, the fluid being contained in a Pyrex vessel (approximately 50 centimeters (cm) in length by 8 cm in diameter) fitted with air inlet and outlet ports. In addition, suspend cast iron and steel coupons above the fluid level to assess vapor phase corrosion. Heat the hydraulic fluid to a set point temperature of 70° C. and maintain the fluid at that for 200 hours while blowing air through the fluid at a rate of 100 milliliters per minute (ml/min). After each 24 hour period that the fluid is at 70° C., top the fluid off with de-ionised water to replace any evaporated fluid.

Upon completion of the 200 hours, allow the fluid to return to ambient temperature (nominally 25° C.), then dry the coupons and wash them with acetone. Visually inspect each coupon and rate it on a scale of 1 to 5, where a rating of 5 indicates no staining or corrosion, a rating of 4 indicates surface corrosion in excess of 0 percent (%) up to 10%, a rating of 3 indicates surface corrosion of at least 10% up to 50%, a rating of 2 indicates surface corrosion of at least 50% up to 80% and a rating of 1 indicates severe staining or corrosion as in more than 80% up to 100%. Assess both the front side and the back side of each coupon is assessed and report measurements. A score of 4 or more for all metals tested, except for aluminium where a score of 3 may be used, constitutes an acceptable corrosion performance. A lower acceptable score for aluminium relates to its nature as an amphoteric metal that is susceptible to staining in water-based lubricants with a pH in excess of 9. As most hydraulic equipment contains limited amounts of aluminium, a score of 3 or more is acceptable as scores for other metals that appear in greater abundance in hydraulic equipment merit greater attention. Wear Testing

Use a Vickers Vane V-104C pump and a variation of ASTM D-7043 to evaluate potential lubrication properties of hydraulic fluids. For the variation, use a one gallon reservoir, rather than a five gallon reservoir according to ASTM D-7043, and implement a comprehensive cleaning procedure subsequent to each test run to effectively eliminate contamination from one test run to a succeeding test run. In the comprehensive cleaning procedure, strip the machine, clean the stripped parts and rebuild the machine, replacing worn parts as needed. Conduct wear testing at a pressure of 2000 psig (14 MPa), a rotary speed of 1200 revolutions per minute (rpm), a hulk fluid temperature of 65° C. and a test duration of 100 hours. Determine weight loss of pump vanes and ring and report combined weights as total weight loss during testing for each test run. Reserve Alkalinity (RA) Testing

Dilute approximately 10 ml (weighed to the nearest 0.1 ml) of a sample fluid in 50 ml of deionized water to yield a dilute fluid solution. Use an autotitrator to potentiometrically titrate the dilute fluid solution with standardized 0.100 Normal (0.100 N) aqueous hydrochloric acid (HCl). Calculate RA using the following equation:

Prepare a plurality of glycol/water solutions having compositions as shown in Table 1 below using the following procedure: to a 1000 ml beaker, add water, then diethylene glycol, followed by amine and alkanolamine, either separately together or in any order. Stir contents of the beaker at ambient temperature (nominally 25° C.) until the contents have a visual appearance of a clear, homogeneous solution. Add decanoic acid with continued stirring at ambient temperature until the contents regain the visual appearance. Add tolyltriazole with continued stirring until the tolyltriazole appears to be fully dissolved. While ambient temperature typically suffices, mild heating (e.g. up to 50° C.) may enhance dissolution of the tolyltriazole. Finally, add polyglycol (polyalkylene glycol) with continued stirring at ambient temperature until contents of the beaker regain the appearance of a clear, homogeneous solution.

In Tables 1-4 below, AMP=2-amino-2-methyl-1-propanol (commercially available from Angus Chemical under the trade designation “AMP-95”); MIPA=mono-isopropanolamine; TEA=triethanolamine; DMEA=N,N-dimethylethanolamine; DEEA N,N-diethylethanolamine; DEG=diethylene glycol; and PAG=polyalkylene glycol (also known as “d-PAG-A”, a developmental glycerol initiated polyalkylene glycol having an ethylene oxide content of 75 percent by weight (wt %) and a propylene oxide content of 25 wt %, in each case based upon total PAG weight, a molecular weight of approximately 25,300, a hydroxyl group (OH) percentage of 0.2, and a viscosity, at 210 degrees Fahrenheit ((° F.) (93.3 degrees centigrade (° C.)), of 11800 centistokes (cSt) (0.012 square meters per second (m2/s)).

Longer term testing than that summarized in Table 1 above suggests that, by maintaining RA within a range of from 150 ml to 200 ml, one realizes better pump performance than that provided by water/glycol fluids that contain the same components, but have a reserve alkalinity of less than 150 ml or greater than 200 ml. Values less than 150 ml trend toward rapid depletion of the reserve amine levels and in turn, ferrous corrosion problems and higher pump wear rates, whereas values in excess of 200 ml provide poor aluminium compatibility. Ex 3-8 and Comp Ex N-T

Replicate Ex 1 above with formulation changes as shown in Table 2 below. The formulations contain fixed amounts of water, PAG (d-PAG-A), decanoic acid and tolyltriazole, and varying amounts of AMP-95, DEEA and/or DMEA, and DEG as shown in Table 2. Table 2 also contains corrosion performance, pH and reserve alkalinity test data.

Replicate Ex 5 with changes to prepare a plurality of water/glycol fluid compositions with varying water and DEG contents as shown in Table 3 below. Reduce the amount of tolyltriazole from 0.1 wt % to 0.06 wt % and add 0.04 wt % of an ethylene oxide/propylene oxide (EO/PO) copolymer having an ethylene oxide content of 28 wt %, based upon copolymer weight (UCON™ Lub 1281, commercially available from The Dow Chemical Company) to counter the reduction in tolyltriazole amount, each wt % being based upon total water/glycol fluid composition weight.

Subject those formulations that have water contents of 48 wt %, 50 wt %, 52 wt % and 54 wt %, to wear testing to determine total ring and vane wear, pH measurement, before and after wear testing, alkalinity (ml) before and after wear testing, and kinematic viscosity at 40° C. (KV40), before and after wear testing. Summarize test results in Table 4 below.

Replicate Ex 9-14 and CEx U-V with changes to replace d-PAG-A with d-PAG-B (Table 5 hydraulic performance data), d-PAG-C (Table 6 hydraulic performance data) and PAG-D (Table 7 hydraulic performance data). “d-PAG-B is a trimethylolpropane-based, developmental PAG with the same wt % of ethylene oxide and propylene oxide as d-PAG-A, but molecular weight of approximately 42630 and a viscosity at 210° F. (99° C.) of 11525 cSt (0.012 m2/s). “d-PAG-C is a pentaerythritol-based, developmental FAG with the same wt % of ethylene oxide and propylene oxide as d-PAG-A, but a molecular weight of approximately 46625 and a viscosity at 210° F. (99° C.) of 12025 cSt (0.012 m2/s). PAG-D is a PAG (commercially available from The Dow Chemical Company under the trade designation UCON™ lubricant 75H-380,000) with the same wt % of ethylene oxide and propylene oxide as d-PAG-A, but a molecular weight of approximately 25,000 and a viscosity at 210° F. (99° C.) of approximately 11800 cSt (0.012 m2/s).

The data presented in Tables 4-7 demonstrate very desirable (less than 100 mg, preferably less than 50 mg) total ring and wear performance for water-glycol hydraulic fluids representative of the present invention based upon a combination of amines and alkanolamines with a variety of thickeners at various water contents. Ex 11-25 all show the very desirable total ring and wear performance at water levels in excess of 44 wt %, with Ex 11, Ex 15 and Ex 20 at 46 wt %, Ex 13, Ex 17, Ex 22 and Ex 24 at 50 wt %, Ex 25 at 51 wt %, Ex 14 and Ex 18 at 52 wt % and Ex 19 at 54 wt %. Conventional water-glycol hydraulic fluids that yield a less than 100 mg total ring and wear performance contain water at no more than 40 wt %. Skilled artisans recognize that results such as those presented for CEx X-CEx Z, all of which have the same composition, are typical as one exceeds a total ring and wear performance of 250 mg. One possible explanation for such erratic results is that particulate debris generated during wear testing further accelerates wear. Ex 26-34 and CEx AD-AG

Replicate Ex 15-25 and CEx W-AC with changes to substitute a higher viscosity developmental PAG, either d-PAG-E (glycerol-based), d-PAG-F (trimethylolpropane-based) or PAG-G, for d-PAG-A and increase the amount of PAG, whether d-PAG-E, d-PAG-F or PAG-G, from 11.75 wt % to 16.6 wt %, with a complementary decrease in amount of DEG relative to formulations having the same water content as those shown in Table 3 above. For example, a formulation that has a water content of 50 wt % has a d-PAG-A content of 11.75 wt % and a DEG content of 34.95 wt % whereas a formulation with the same water content has a d-PAG-D content of 16.5 wt % and a DEG content of 30.2 wt %. In other words, as d-PAG content increases by a set amount, DEG content decreases by the set amount. d-PAG-E and d-PAG-F both have the same wt % of ethylene oxide and propylene oxide, but d-PAG-D has a viscosity at 104° F. (40° C.) of 15900 cSt (0.016 m2/s) and a molecular weight of approximately 22,000, and d-PAG-E has a viscosity at 104° F. (40° C.) of approximately 19180 cSt (0.019 m2/s) and a molecular weight of approximately 22,000. PAG-G is a PAG (commercially available from The Dow Chemical Company under the trade designation UCON™ lubricant 75H-90,000) with the same wt % of ethylene oxide and propylene oxide as d-PAG-A, but a molecular weight of approximately 12,000 and a viscosity at 210° F. (99° C.) of 2500 cSt (0.002 m2/s). Tables 8 through 10 below summarize test data for formulations that contain, respectively, d-PAG-E, d-PAG-F and PAG-G, with water contents as shown. The test data presented in Tables 8 through 10 include initial viscosity measurements as well as viscosity measurements after elapsed times of 24 hours, 48 hours, 72 hours and 100 hours.

The data presented in Tables 8 through 10 show similar trends to that shown in Tables 4-7. The data also show that compositions of the present invention have a greater range of potential water contents that deliver very desirable total ring and vane wear performance with a glycerol-based PAG viscosity modifier (d-PAG-D) than with a trimethylolpropane-based PAG viscosity modifier (d-PAG-E). Even with d-PAG-E, total ring and wear vane performance of less than 100 mg occurs at water contents of 40 wt % and 44 wt %. A water content in excess of 44 wt %, but less than 50 wt % for d-PAG-E-containing formulations, should also produce a total ring and vane wear performance of less than 100 mg.

Morpholine-free water-hydraulic liquid compositions within the scope of appended claims, but not expressly illustrated in this example section, should produce comparable results, some with relatively narrow water content range, as in Table 9, some with an intermediate water content range, as in Table 10, and some with a broader water content range, as in Table 8.

This invention relates generally to water-glycol hydraulic fluid compositions and more particularly to such compositions that are substantially morpholine-free.

United States Patent (USP) 4,855,070 to Lewis discloses a water-glycol energy transmitting fluid that comprises a) from 30 percent by weight (wt%) to 40 wt% water, b) diethylene glycol, c) from 0.8 wt% to 5.0 wt% of an aliphatic carboxylic acid having 9 to 12 carbon atoms (Cy-Cp) inclusive, d) a water-soluble polymeric viscosity control agent, e) a corrosion inhibiting amount of at least one corrosion inhibitor, and f) a metal deactivator, each wt% being based upon total fluid weight. Illustrative corrosion inhibitors include alkyl amines such as propylamine and dimethylaminopropylamine; alkanolamines such as monoethanolamine, N, N-dimelhylethanolamine or an arylamine such as aminotoluene; another amine-type corrosion inhibitor such as ethylenediamine, morpholine or pyridine; or mixtures thereof. The metal deactivator functions as a chelating agent for copper and copper alloys. Illustrative water-soluble polymeric viscosity control agents include poly( alkylene oxide) polymers, alkylene oxide adducts of alkyl phenols, polyalkyl methacrylates. urethane polymers, polyamidc esters, and polyamidc alkoxylates, with poly( alkylene oxide) polymers being preferred.

Modern water/glycol hydraulic fluids constitute highly engineered producls and comprise a complex mixture of components. Key components of such fluids, in addition to water and glycol, include a high molecular weight (e.g., a number average molecular weight of more than 6,000) polyglycol (also known as an ""alkylene glycol") as a thickener or water-soluble polymeric viscosity control agent, vapor phase corrosion inhibitors and solution corrosion inhibitors. Such fluids often contain one or more additives including an anti-wear additive that Tonus a surface film between moving metal paits in an apparatus such as a pump, especially during start-up activities for the pump. Vapor phase corrosion inhibitors typically provide a measure of protection for ferrous surfaces, such as steel and cast iron, both commonly found in alloys used to fabricate hydraulic equipment. Solution corrosion inhibitors inhibit corrosion ol metals ottcn used in hydraulic circuits including cast iron, stainless steel, aluminum, brass and copper. Hydraulic fluids that come in contact with a yellow metal, such as brass, typically contain an additive such as tolyltriazole for yellow metal passivation.

Watcr/glycol hydraulic fluids find use in automotive, steel and mining industrial applications that typically require reliable, preferably sustained, performance in operation of

hydraulic equipment as well as a measure of hie iesistance Fire resistance takes on increasing importance in an envnonment whete there is a significant risk of hie due to f luid leakage Resistance to hie does not, however, mean complete heedom from fire as skilled artisans recognize that organic fluids such as glycols, do burn when piesent in suf ficient concentration and exposed to sufficient oxygen, heat and a flame source to ignite at least volatile components ol such organic f luids

A numbei of regional standards foi f ire iesistance ratings of hydraulic fluids exist Foi example, in Noith Ameπca, Factoiy Mutual ccitif ics fluids accoiding to lire resistance iatings in which the fluids aie given a iating of "Pioduct Specified" 01 "Pioduct Approved" with top tiei fluids being certified w ith a "Pioduct Appioved rating In Euiope, cuirent legal lequirements mandate sale of hie iesistant fluids that have 7th Luxembouig accteditation, a combination ol hie resistance and hydraulic wear performance The lattei standard appears to be gaining giound as a global norm foi fire resistance iatings

A geneial purpose water/glycol hydiauhc fluid (sometimes ieferied to as a "hydrolube") marketed by The Dow Chemical Company under the tiade designation UCON I M Hydiolube DG-746 finds use in vane, geai and piston pump hydraulic equipment, all of which operate at a outlet piessuie of up to 3500 pounds pei squaie inch gauge (psig) (24 megapascals (MPa) Higher outlet pressuies typically use an alternate hydrolube such as UC0N I M Hydrolube HP-5046 which is recommended for hydraulic pumps opeiating at pressures up to 5000 psig (34 MPa) I hcsc hydiolubcs arc among many marketed by produc-eis of hydrolubes that contain moipholinc

As industrial demands inciease, paiticularly foi hydraulic equipment that both has a size smaller than cuπent hydraulic equipment and operates under a pressuie in excess ol 5000 psig (30 MPa), hydiauhc equipment under constiuction oi development, tends to have a smallei fluid leservon size than hydiauhc equipment in use in the 199()"s oi even early 2000"s A smaller fluid reseivou tianslates, in turn, to an increased numbei ol times that a hydraulic fluid circulates around a hydraulic ciicuit within such equipment, thereby effectively exposing such fluid to a higliei slicss cnvnoniiicnt than that present in earlier hvdrauhc equipment The higher stress environment usually includes higher bulk fluid temperatures than those expeπenced in such eai hei hydiaulie equipment The highei stiess envnonment can lead to one or more ol viscosity loss, possibly because of sheai instability at the higher picssuics dcgiadation of the hydiauhc fluid sufficient to produce degiadation pioducts such as thei mo-oxidative degiadation pioducts that inciease hydiauhc equipment

component weai rates relative to hydiauhc fluids that lack such degiadation pioducts Totten and Sun in Handbook ot Hydiaulic Fluid Technology, (2000) note, at page 917, that degradation pioducts such as toimic acid have been shown to significantly increase hydraulic wear iates in water glycol hydraulic fluids at levels in excess ol 0 15 pei cent by weight (wt%), based upon total weight ol fluid Smallei hydraulic equipment leads in turn to a lcqunement foi hydiauhc f luids that withstand opeiating in such a highei stiess envnonment

Legislation in certain countries, pπmαπlv those located in Europe, designates secondary amines, such as moiphohne, as iestricted materials because of a potential to form nitrosamines when in contact with sodium nitrite, a commonly used coiiosion inhibitor in f luid and lubπcant formulations As such compounds that contain morphohnc (e g morphohne containing lire iesistant water/glycol hydraulic fluids) also fall in a class ot resliicted inateiials Elimination of morphohne f rom f lie resistant water/glycol hydraulic fluids should take such f luids out of the class of iesti icted matenals

An aspect of an invention embodied in appended claims is a substantially moiphohne-tree water-hydraulic liquid composition, the liquid composition compiising water, a glycol, a polyglycol, an aliphatic caiboxyhc acid that contains from six to 14 caibon atoms, and a combination of amines and alkanolamincs

Compositions of the present invention include an amount of polyglycol or alkylene glycol. The amount preferably lies within a range of from 30 percent by weight to 50 percenl by weight, based upon total composition weight.

Illustrative ulkylene glycols include those selected from a group consisting of ethylene glycol, propylene glycol, diethylene glycol, trielhylene glycol, dipropylene glycol, tripropylene glycol, a "bottom glycols" fraction produced during manufacture of diethylene glycol, and butylene glycol.

The alkylene glycol is preferably a polyalkylene glycol selected from a group consisting of random copolymers of ethylene oxide and propylene oxide, more preferably a random copolymer of ethylene oxide and propylene oxide with an ethylene oxide content within a range of from 50 wt% to 90 wt% and a complementary propylene oxide content within a range of from 10 wt% to 50 wt%, in each case based upon total weight of ethylene oxide and propylene oxide, with complementary amount of propylene oxide, when added lo amount of ethylene oxide, equalling 100 percent by weight. The random copolymer of ethylene oxide and propylene oxide more preferably has an ethylene oxide content within a range of from 70 wt% to 80 wt%, with a complementary propylene oxide content within a range of from 20 wt% to 30 wt%. The random copolymer of ethylene oxide and propylene oxide still more preferably has an ethylene oxide content within a range ol from about 74 wt% to 76 wt %, with complementary propylene oxide content within a range of from 26 wtf7r to 24 wl%. The random copolymer of ethylene oxide and propylene most preferably has an ethylene oxide content of about 75 wl% and a complementary propylene oxide content of about 25 wt%.

The polyglycols used in water-liquid compositions of the present invention function as a viscosity modifier or thickening agent and have a number average molecular weight that is preferably within a range of from 6.000 to 40,000, more preferably within a range of from 8,000 to 30,000, and still moie prefeiably within a iange of from aboul 10.000 to 25,000. Skilled artisans understand that a viscosity modifier increases composition viscosity, or thickens it, relative Io an identical composition save for absence of the viscosity modifier. Without a viscosity modifier, composition viscosity of a water-glycol

In prepaπng such polyglycols, react a random mixed teed ot ethylene oxide and propylene oxide onto an initiatoi such as glycerol pentaerythπtol tπmethylolpropane 01 dicthylenc glycol Paul Matlock and William R Brown describe such pieparation in a chapter dev oted to polyalkylene glycols in Synthetic Lubricants & High Perlormance Functional Fluids ( 1991 ) chaptei 4 p 101 123 edited by Ronald Shubkin

Substantially moipholine tiee watei -hydraulic liquid compositions ot the piesent inv ention include watei to piomote tue iesistance diethylene glycol toi low tempeiatuie contiol, a shoi t chain (six to fouiteen caibon atoms (Q to Cu)) aliphatic carboxylic acid such as decanoic acid (sometimes ielerred to as " capi ic acid") or nonanoic acid (sometimes know n as pci lagonic ac id) as an anti weai component tor pump start and boundary lubi ication tolyltπa/ole lor yellow metal passivation and polyalkylene gl>col as a high molecular weight viscosity modifier toi hydrodynamic lubt icalion

By way of illustration, but not by limitation, preparation of substantially morpholine-free, preferably completely morpholine-free, water-hydraulic liquid compositions of the present invention suitably involves mixing or stirring together a combination of water, glycol (e.g. dielhylene glycol), primary amine and tertiary amine (also referred to herein as ""alkanolamine") at, for example, ambient temperature (nominally 25 0C). Stirring at this temperature preferably continues until the combination appears as a visually clear, homogeneous solution. Add the aliphatic carboxylic acid with continued stirring, preferably until the solution once again appears as a visually clear, homogeneous solution. If one chooses to add a yellow metal passivator such as tolyl triazolc, add it next with stirring to facilitate dissolution of the yellow metal passivator. Mild (up to 50 °C) heating may enhance dissolution of the yellow metal passivator. Following dissolution of the yellow metal passivator, or following addition of the aliphatic carboxylic acid if one omits a yellow metal passivator, add a polyglycol or polymeric thickening agent with continued stirring until the solution once again takes on appearance as a visually clear, homogeneous solution.

The illustrative preparation of water-hydraulic liquid compositions of the present invention employs ""mild"" temperatures of no more than 50 0C. While higher temperatures may be used if desired, such higher temperatures need not be employed. One should, however, avoid temperatures in excess of 160 0C to substantially preclude formation of amides. Amides are neither needed nor desired in compositions of the present invention.

The substantially morpholine-free water-hydraulic liquid compositions of the present invention preferably yield a total weight loss of ring and vanes in a Vickers Vane V 104C pump test of less than 100 milligrams as measured in accord with ASTM D7043 as described below. The total weight loss is preferably less than 50 milligrams.

The substantially morpholinc-frcc water-hydraulic liquid compositions of the present invention have a water content that is greater than 0 wt%. preferably greater than 40 wt%, more preferably more than 44 wl%. in each case based upon total composition weight. The amount of water is preferably less than that which leads to a total ring and vane weight

Measure coriosion perfoi mance of a water/glyeol hydraiilrc solution both solution phase and vapour phase using a modification of American Standard loi Testing and Matenals (ASTM) G ^ l -72 Immeise steel, cast iron, copper brass and aluminium coupons in the hvdiauhc fluid the fluid being contained in a Pyiex \essel (approximately 50 centimeters (cm) in length by 8 cm in diametei ) fitted w ith an inlet and outlet ports In addition, suspend cast uon and steel coupons above the fluid level to assess vapor phase coiiosion Heat the hydiaulic fluid to a set point temperatuie of 70 C and maintain the fluid at that lor 200 houis while blow ing air through the tlurd at a iate of 100 milliliters pet minute (ml/min) After each 24 hour peπod that the fluid is at 70 C, top the fluid oil with de ionised water to replace any evaporated fluid

Upon completion of the 200 houis, allow the lluid to return to ambient tempeiatuie (nominally 25 0C) then diy the coupons and wash them with acetone Visually inspect each coupon and rate it on a scale of I to 5, where a iating of 5 indicates no staining or coiiosion, a rating ol 4 indicates surface coirosion in excess of 0 percent (%) up to 10% a iating of λ indicates surface coriosion of at least 10% up to 50% a rating of 2 indicates surface coirosion of at least 50% up to 80% and a rating of I indicates seveie staining oi corrosion as in moie than 80% up to 100% Assess both the lronl side and the back side of each coupon is assessed and report measurements A score of 4 oi more foi all metals tested except lor alunrrnrum w here a score ot 3 ma> be used constitutes an acceptable coriosion pciloimance A lowei acceptable scoie lor aluminium relates to its nature as an amphoteiic metal that is susceptible to staining in water-based lubricants with a pi I in excess ol 9 As most hydraulic equipment contains limited amounts ot aluminium a score of 3 or moie is acceptable as scores foi other metals that appeal in greatci abundance in hydraulic equipment merit gieatei attention

Use a Vickcrs Vane V- 104C pump and a variation of ASTM D-7043 to evaluate potential lubrication properties of hydraulic fluids. For the variation, use a one gallon reservoir, rather than a five gallon reservoir according to ASTM D-7043, and implement a comprehensive cleaning procedure subsequent to each test run to effectively eliminate contamination from one test i un to a succeeding test run. In the compiehensive cleaning piocedure, strip the machine, clean the sti ipped paits and iebuild the machine, ieplacing worn paits as needed. Conduct wear testing at a pressure of 2000 psig ( 14 MPa), a iotai y speed of 1200 revolutions per minute (rpm), a bulk fluid temperature of 65 0C and a test duration of 100 hours Determine weight loss of pump vanes and ring and report combined weights as total weight loss during testing foi each test run Reserve Alkalinity (RA) Testing

Piepare a pluiahty of glycol/watei solutions having compositions as shown in Table 1 below using the following pioceduie to a 1000 ml beakei, add water, then diethylene glycol, followed by amine and alkanolamine, either separately together oi in any oidei Stii contents of the beakei at ambient tempeiatuie (nominally 25 0C) until the contents have a visual appeal ance of a clcai, homogeneous solution Add decanoic acid with continued stiiπng at ambient tempeiature until the contents regain the visual appeal ance Add tolylti iazole with continued Stirl ing until (he (olyltiiazole appears to be fully dissolved While ambient lerπpeiatuie typically sullices, mild heating (e g up to 50 0C) may enhance dissolution of the tolyltπa/ole Finally, add polyglycol (pυlyalkylene glycol) with continued storing at ambient tempeiatuie until contents of the beakei iegain the appeal ance of a cleai, homogeneous solution

In Tables 1 -4 below, AMP = 2-amino-2-methyl- l -propanol (commeicially available from Angus Chemical undci the tiade designation "AMP-95"),, MIPA = mono- lsopiopanolamine, TEA = tπethanolamine DMEA = N, N-dimcthylcthanolamine, DEEA = N, N diethylethanolamine, DFG = diethylene glycol, and PAG = polyalkylene glycol (also known as "d PAG A", a developmental glycerol initiated polyalkylene glycol having an ethylene oxide content of 75 peicent by weight (wt%) and a propylene oxide content of 25 wt%, in each case based upon total PAG weight, a moleculai weight ot approximately 25,300, a hydioxyl group (OH) percentage ot 0 2, and a viscosity, at 210 degiees Fahienheit ((0F) (93 3 degrees centigrade (°C)),of 1 1800 centistokes (cSt) (0 012 squaie meteis pei second (πr/s))

Longer term testing than that summarized in Table 1 above suggests that, by maintaining RA within a range ot from 150 ml to 200 ml, one realizes better pump performance than that piovidcd by water/glycol fluids that contain the same components, but have a reserve alkalinity of less than 150 ml or greater than 200 ml. Values less than 150 ml trend toward rapid depletion of the reserve amine levels and in turn, ferrous coπosion pioblems and higher pump weai rales, whereas values in excess ot 200 ml provide pooi aluminium compatibility. Ex 3-8 and Comp Ex N-T

Replicate Ex 5 with changes to prepaie a plurality of water/glycol fluid compositions with varying water and DEG contents as shown in Table 3 below. Reduce the amount of tolyltriazole from 0. 1 wt% to 0.06 wt% and add 0.04 wt% of an ethylene oxide/propylene oxide (EO/PO) copolymer having an ethylene oxide content of 28 wf/t , based upon copolymer weight (UCON " M Lub 1281 , commercially available from The Dow Chemical Company) to counter the reduction in tolyltriazole amount, each wt% being based upon total water/glycol lluid composition weight.

Subject lhose foπnulaύυns that have water contents of 48 wt%, 50 wl%, 52 wlΨc and 54 wt%, to wear testing to determine total ring and vane wear, pH measurement, before and after wear testing, alkalinity (ml) before and after wear testing, and kinematic viscosity at 40 °C (KV40), before and after wear testing. Summarize test results in Table 4 below.

Replicate Kx 9- 14 and CHx U-V with changes to replace d-PAG-A with d-FAG-B (Table 5 hydraulic performance data), d-PAG-C (Table 6 hydraulic performance data) and PAG-D (Table 7 hydraulic performance data). "d-PAG-B is a trimethylolpropane-based, developmental PAG with the same wt% of ethylene oxide and propylene oxide as d-PAG- A, bυt-a molecular weight of approximately 42630 and a viscosity at 210 "F (99 0C) of 1 1525 cSt (0.012 πr/s). ""d-PAG-C is a pentaerythπtol-based, developmental PAG with the same wt% of ethylene oxide and propylene oxide as d-PAG-A, but a molecular weight of approximately 46625 and a viscosity at 2 K) 0F (99 "C) of 12025 cSl (0.012 πr/s). PAG-D is a PAG (commercially available from The Dow Chemical Company under the trade designation UCON 1 M lubricant 75H-380,000) with the same wt% of ethylene oxide and propylene oxide as d-PAG-A, but a molecular weight of approximately 25.000 and a viscosity at 210 0F (99 0C) of approximately 1 1800 cSt (0.012 πr/s).

The ddld piesenled in T ables 4 7 demonstiate veiy desirable (less than 100 mg pieteiably less than 50 mg) total nng and weai peitoimance foi watei-glycol hydraulic fluids repiesentative of the piesent invention based upon a combination ol amines and alkanolamines with a variety of thickeners at various watei contents Ex 1 1-25 all show the vei y desirable total ring and weai peifoimance at water levels in excess of 44 w

1 1 , Ex 15 and Ex 20 at 46 wt%, Ex 13, Ex 17. Ex 22 and Ex 24 at 50 wt%, Ex 25 al 51 wt%, Ex 14 and Ex 18 at 52 wt% and Ex 19 at 54 wt%. Conventional water-glycol hydraulic fluids that yield a less than 100 mg total ring and wear performance contain water at no more than 40 wt%. Skilled artisans recognize that results such as those presented for CEx X - CEx Z, all of which have the same composition, are typical as one exceeds a total ring and wear performance of 250 mg. One possible explanation for such erratic results is that particulate debris generated during wear testing further accelerates wear. Ex 26-34 and CEx AD-AG

Replicate Ex 15-25 and CEx W-AC with changes to substitute a higher viscosity developmental PAG, cither d-PAG-E (glycerol-based), d-PAG-F (trimethylolpropane- based) or PAG-G, for d-PAG-A and increase the amount of PAG, whether d-PAG-E, d- PAG-F or PAG-G, from 1 1.75 wt% to 16.6 wt%, with a complementary decrease in amount of DEG relative to formulations having the same water content as those shown in Table 3 above. For example, a formulation that has a water content of 50 wt% has a d-PAG-A content of 1 1.75 wt% and a DEG content of 34.95 wt% whereas a formulation with the same water content has a d-PAG-D content of 16.5 wt%> and a DEG content of 30.2 wt"/o. In other words, as d-PAG content increases by a set amount, DEG content decreases by the set amount. d-PAG-E and d-PAG-F both have the same wt% of ethylene oxide and propylene oxide, but d-PAG-D has a viscosity at 104 °F (400C) of 15900 cSt (0.016 nr/s) and a molecular weight of approximately 22,000, and d-PAG-E has a viscosity at 10