Hydraulic fluids properties

EPM is preferred for dynamic applications because its age resistance retains initial product design properties over time and environmental exposure. EPDM is preferred for its high resilience. EPM is resistant to acids, bases, and hot detergent solution. EPM and EMDM are resistant to salt solutions, oxygenated solvents, and synthetic hydraulic fluids. Properties are determined by the composition of the base compound. 

The silicone oils and silicone resins find application as (i) lubricants (their change of viscosity with temperature is small), (ii) hydraulic fluids (they are unusually compressible), (iii) dielectric fluids, (iv) for the pro duction of water-repellant surfaces, and (v) in the electrical industry (because of their high insulating properties). 

FLUOROTRIAZINES Riag-fluoriaated triaziaes are used ia fiber-reactive dyes. Perfluoroalkyl triaziaes are offered commercially as mass spectral markers and have been iatensively evaluated for elastomer and hydraulic fluid appHcations. Physical properties of representative fluorotriaziaes are listed ia Table 13. Toxicity data are available. For cyanuric fluoride, LD g =3.1 ppm for 4 h (iahalatioa, rat) and 160 mg/kg (skin, rabbit) (127). 

Sulfolene (2) is the next most commercially important sulfone after sulfolane. Besides its precursor role in sulfolane manufacture, 3-sulfolene is an intermediate in the synthesis of sulfolanyl ethers, which are used as hydrauHc fluid additives (see Hydraulic fluids). 3-Sulfolene or its derivatives also have been used in cosmetics (qv) and slimicides. Selected physical properties of 3-sulfolene are Hsted in Table 3. 

Hydraulic Fluids and Lubricants. The use of borate esters in hydrauHc fluids (qv) and lubricants (see Lubrication and lubricants) has been described in numerous patents (40,43,44). A variety of borate esters have been described that can be used as multiflinctional lubricant additives having antiwear and antifriction properties (45). 

Metal- Working and Hydraulic Fluids. In the preparation of fluids for metal-working and hydrauflcs, the trend has been to replace organic-based materials with aqueous-based materials. Neodecanoic acid has found apphcation in these newer fluids as a corrosion inhibitor and a viscosity improver. For example, neodecanoic acid is used in an aqueous hydrauflc fluid concentrate for corrosion inhibition and improved antiwear properties (101), in the preparation of a thickened aqueous hydrauflc fluid to reduce viscosity loss (102), and in a water-soluble metal working oil to reduce corrosion (103). In a similar vein, neodecanoic acid has been used in antifreeze concentrates for corrosion inhibition (104). 

Fluoroelastomer (Vitou, Fluorel 2141, Kel-F) 450 Can be used at high temperatures with many fuels, lubricants, hydraulic fluids, solvents, highly resistant to ozone, weathering. Good mechanical properties. 

Leather To 210 Good mechanical properties for sealing. Resistant to alcohol, gasobne, many oils and solvents, synthetic hydraulic fluids, water. 

Both the dipolymers and terpolymers have excellent resistance to hydrocarbons found m petroleum-based fuels and lubricants The 69 5% F terpolymer resists swellmg m blended fuels that contain metlianol and can be used in contact with certain phosphate ester-based hydraulic fluids Terpolymers are preferred for contact with aromatic solvents, although either type performs well in higher alcohols VDF-based elastomers dissolve m polar aprotic solvents such as ketones, esters, amides, and certam ethers These elastomers are therefore not suitable for contact with fluids that contain substantial amounts of these solvents because of excessive swell and consequent loss of mechanical properties... 

Many engineering thermoplastics (e.g., polysulfone, polycarbonate, etc.) have limited utility in applications that require exposure to chemical environments. Environmental stress cracking [13] occurs when a stressed polymer is exposed to solvents. Poly(aryl ether phenylquin-oxalines) [27] and poly(aryl ether benzoxazoles) [60] show poor resistance to environmental stress cracking in the presence of acetone, chloroform, etc. This is expected because these structures are amorphous, and there is no crystallinity or liquid crystalline type structure to give solvent resistance. Thus, these materials may have limited utility in processes or applications that require multiple solvent coatings or exposures, whereas acetylene terminated polyaryl ethers [13] exhibit excellent processability, high adhesive properties, and good resistance to hydraulic fluid. 

After the type of system has been selected, many of these same factors must be considered in selecting the fluid for the system. This chapter is devoted to hydraulic fluids. Included in it are sections on the properties and characteristics desired of hydraulic fluids types of hydraulic fluids hazards and safety precautions for working with, handling, and disposing of hydraulic liquids types and control of contamination and sampling. 

Viscosity is one of the most important properties of hydraulic fluids. It is a measure of a fluid s resistance to flow. A liquid such as gasoline which flows easily has a low viscosity, and a liquid such as tar which flows slowly has a high viscosity. The viscosity of a liquid is affected by changes in temperature and pressure. As the temperature of liquid increases, its viscosity decreases. That is, a liquid flows more easily when it is hot than when it is cold. The viscosity of a liquid will increase as the pressure on the liquid increases. 

In order to take into account the effect of surface tension and micro-channel hydraulic diameter, we have applied the Eotvos number Eo = g(pL — pG)d /(y. Eig-ure 6.40 shows the dependence of the Nu/Eo on the boiling number Bo, where Nu = hd /k] is the Nusselt number, h is the heat transfer coefficient, and k] is the thermal conductivity of fluid. All fluid properties are taken at the saturation temperature. This dependence can be approximated, with a standard deviation of 18%, by the relation ... 

Compound 1 is used as a solvent in the food, paint, resin/plastics, soap and woodpulp/paper industries, and as a plasticizer. Compound 2 is used as an intermediate for the manufacture of hydraulic fluid additives and cosmetics. Sulphonal (2 2-his(ethylsulphonyl)-propane), another important sulphone, is a colourless solid, stable to acids and alkalis, with hypnotic properties. 

These experts collectively have knowledge of hydraulic fluids s physical and chemical properties, toxicokinetics, key health end points, mechanisms of action, human and animal exposure, and quantification of risk to humans. All reviewers were selected in conformity with the conditions for peer review specified in Section 104(I)(13) of the Comprehensive Environmental Response, Compensation, and Liability Act, as amended. 

Physical and Chemical Properties of Hydraulic Fluid Products... 

No studies were located that examined the toxicokinetics of mineral oil, organophosphate ester, or polyalphaolefin hydraulic fluids in humans or animals, with the exception of a study examining absorption in rats after exposure to a hydraulic fluid containing 99.9% cyclotriphosphazene (Kinkead and Bashe 1987) and the absorption and metabolism of Reolube HYD46, another organophosphate hydraulic fluid (Ciba-Geigy 1985). This section, therefore, discusses available information on the toxicokinetics of major components of these classes of hydraulic fluids or of materials that maybe expected to display similar toxicokinetic properties based on similar physical and chemical characteristics. It should be emphasized that many hydraulic fluids are complex mixtures of chemicals that may include some chemicals which may not share toxicokinetic properties with the major components. 

No studies were located that examined the toxicokinetics of polyalphaolefins in humans or animals, but the similarities in physical and chemical properties between polyalphaolefins and hydrocarbons in mineral oil indicate that the toxicokinetics of polyalphaolefins may be similar to those of hydrocarbons in mineral oil hydraulic fluids. 

Organophosphate Ester Hydraulic Fluids. Neurotoxicity is a concern from acute dermal, inhalation, or oral exposure to organophosphate ester hydraulic fluids because of the well-established susceptibility of humans to the cholinergic and delayed neuropathic properties of certain organophosphate ester compounds... 

Comparative Toxicokinetics. The toxicokinetics database is wholly inadequate with respect to comparing toxicokinetics across species, largely because of the dearth of baseline data regarding absorption, distribution, metabolism, and excretion in any species after exposure to mineral oil hydraulic fluids, organophosphate ester hydraulic fluids, or polyalphaolefin hydraulic fluids. Also, no studies were located on the toxicokinetic properties of hydraulic fluids in humans. 

In the past, hydraulic fluids using mineral oils sometimes included such additives as PCBs to improve the thermal resistance or other properties of the resulting fluids. While such uses of PCBs have been discontinued, PCBs at NPL sites may be encountered as a component where hydraulic fluids are a site contaminant (ATSDR 1993b). 

Most hydraulic fluids contain additives that impart needed properties (Papay 1989, 1991 Wills 1980). 

Information regarding the physical and chemical properties of selected hydraulic fluid products is shown in Table 3-4. Physical and chemical properties of selected hydraulic fluid components are shown in Table 3-5. 

The physical properties important for the projected use of hydraulic fluids are viscosity, density, foaming behavior, and fire resistance. There is no generally recognized test method for measuring flammability of hydraulic fluids, although various test methods maybe utilized (Moller 1989). 

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