Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M177/00—Special methods of preparation of lubricating compositions; Chemical modification by after-treatment of components or of the whole of a lubricating composition, not covered by other classes
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  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M169/00—Lubricating compositions characterised by containing as components a mixture of at least two types of ingredient selected from base-materials, thickeners or additives, covered by the preceding groups, each of these compounds being essential
  • C10M169/04—Mixtures of base-materials and additives
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  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M171/00—Lubricating compositions characterised by purely physical criteria, e.g. containing as base-material, thickener or additive, ingredients which are characterised exclusively by their numerically specified physical properties, i.e. containing ingredients which are physically well-defined but for which the chemical nature is either unspecified or only very vaguely indicated
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2205/00—Organic macromolecular hydrocarbon compounds or fractions, whether or not modified by oxidation as ingredients in lubricant compositions
  • C10M2205/02—Organic macromolecular hydrocarbon compounds or fractions, whether or not modified by oxidation as ingredients in lubricant compositions containing acyclic monomers
  • C10M2205/026—Butene
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2205/00—Organic macromolecular hydrocarbon compounds or fractions, whether or not modified by oxidation as ingredients in lubricant compositions
  • C10M2205/02—Organic macromolecular hydrocarbon compounds or fractions, whether or not modified by oxidation as ingredients in lubricant compositions containing acyclic monomers
  • C10M2205/028—Organic macromolecular hydrocarbon compounds or fractions, whether or not modified by oxidation as ingredients in lubricant compositions containing acyclic monomers containing aliphatic monomers having more than four carbon atoms
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2205/00—Organic macromolecular hydrocarbon compounds or fractions, whether or not modified by oxidation as ingredients in lubricant compositions
  • C10M2205/04—Organic macromolecular hydrocarbon compounds or fractions, whether or not modified by oxidation as ingredients in lubricant compositions containing aromatic monomers, e.g. styrene
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2205/00—Organic macromolecular hydrocarbon compounds or fractions, whether or not modified by oxidation as ingredients in lubricant compositions
  • C10M2205/17—Fisher Tropsch reaction products
  • C10M2205/173—Fisher Tropsch reaction products used as base material
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2209/00—Organic macromolecular compounds containing oxygen as ingredients in lubricant compositions
  • C10M2209/02—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • C10M2209/08—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing monomers having an unsaturated radical bound to a carboxyl radical, e.g. acrylate type
  • C10M2209/084—Acrylate; Methacrylate
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2020/00—Specified physical or chemical properties or characteristics, i.e. function, of component of lubricating compositions
  • C10N2020/01—Physico-chemical properties
  • C10N2020/02—Viscosity; Viscosity index
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2020/00—Specified physical or chemical properties or characteristics, i.e. function, of component of lubricating compositions
  • C10N2020/01—Physico-chemical properties
  • C10N2020/04—Molecular weight; Molecular weight distribution
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2030/00—Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2030/00—Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
  • C10N2030/02—Pour-point; Viscosity index
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2030/00—Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
  • C10N2030/08—Resistance to extreme temperature
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2030/00—Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
  • C10N2030/18—Anti-foaming property
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2030/00—Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
  • C10N2030/68—Shear stability
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2040/00—Specified use or application for which the lubricating composition is intended
  • C10N2040/08—Hydraulic fluids, e.g. brake-fluids
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2070/00—Specific manufacturing methods for lubricant compositions

Definitions

• This invention is directed to processes to make shock absorber fluids having improved performance properties.
• the present invention provides a process to make a shock absorber fluid, comprising: a. selecting a base oil fraction having: consecutive numbers of carbon atoms, a kinematic viscosity at 100°C between 1.5 and 3.5, and less than 10 wt% naphthenic carbon; and b. blending the base oil fraction with less than 4.0 wt% combined viscosity index improver and pour point depressant, based on the total shock absorber fluid, to produce the shock absorber fluid having an air release after 1 minute by DIN 51381 of less than 0.8 vol%.
• the current invention provides a process to make a shock absorber fluid, comprising: a. selecting a Fischer-Tropsch derived base oil that is an XLN grade, an XXLN grade, or a mixture of XLN grade and XXLN grade; b. blending the Fischer-Tropsch derived base oil with an effective amount of at least one additive; wherein the shock absorber fluid meets the specifications for Kayaba 0304- 050-0002 or VW TL 731 class A.
• FIGURE 1 illustrates the plot of Kinematic Viscosity at 100 °C in mm 2 /s vs. viscosity index, providing the equations for calculation of the lower limits for viscosity index of:
• FIGURE 3 illustrates the plots of Kinematic Viscosity at 100°C vs. Noack Volatility, in Weight percent, providing the equations for calculation of the upper limits of wt% Noack Volatility of:
• Dispersed air pockets in oil can increase compressibility and therefore cause shock absorbers to fail DfN 51381 is the test method used to measure air release.
• the sample is heated to a specified test temperature, 50°C . and blown with compressed air. After the air flow is slopped, the time required for the air entrained in the oil to reduce in volume to 0,2% is the air bubble separation time. In the case of our air release testing we measured the volume percent of entrained air at different time periods of 30 seconds, 1 minute, 1 minute 30 seconds, and 2 minutes.
• the shock absorber fluid has a high viscosity index.
• the viscosity index of the shock absorber fluid is greater than or equal to 129. In other embodiments the viscosity index is greater than 150 or 175.
• the shock absorber fluid has a Brookfield viscosity at -30°C that is low. In one embodiment the Brookfield viscosity at -30°C is less than 1,000 mPa.s. In other embodiments the Brookfield viscosity at -30°C is less than 750 mPa.s, less than 500 mPa.s, or less than 250 mPa.s.
• the shock absorber fluid comprises an XLN grade of base oil or an XXLN grade. In another embodiment the shock absorber fluid comprises a mixture of XLN and XXLN grades of base oil.
• An XXLN grade of base oil when referred to in this disclosure, is a base oil having a kinematic viscosity at 100°C between about 1.5 mm 2 /s and about 3.0 mm 2 /s, or between about 1.8 mm 2 /s and about 2.3 mm 2 /s.
• An XLN grade of base oil is a base oil having a kinematic viscosity at 100°C between about 1.8 mm 2 /s and about 3.5 mm 2 /s, or between about 2.3 mm 2 /s and about 3.5 mm 2 /s.
• a LN grade of base oil is a base oil having a kinematic viscosity at 100°C between about 3.0 mm 2 /s and about 6.0 mm 2 /s, or between about 3.5 mm 2 /s and about 5.5 mm 2 /s.
• the shock absorber fluid has an aniline point greater than 88°C.
• the shock absorber fluid comprises a base oil having a kinematic viscosity at 100°C less than 3.0 mm /s, consecutive numbers of carbon atoms, less than 10 wt% naphthenic carbon, and a viscosity index greater than 121.
• the shock absorber fluid has a kinematic viscosity at 100°C less than 5 mm 2 /s and an aniline point greater than or equal to 95°C.
• the shock absorber fluid has an aniline point greater than 100, 105, or 110 0 C.
• the shock absorber fluid has an air release after 1 minute by DIN 51381 of less than 0.8 vol% or less than 0.5 vol%.
• waxy feed refers to a feed having a high content of normal paraffins (n-paraffins).
• a waxy feed will generally comprise at least 40 wt% n-paraffins, greater than 50 wt% n-paraffins, greater than 75 wt% n-paraffins, or greater than 85 wt% n-paraffins.
• the waxy feed has low levels of nitrogen and sulfur, generally less than 25 ppm total combined nitrogen and sulfur, or less than 20 ppm total combined nitrogen and sulfur.
• the Fischer-Tropsch synthesis product usually comprises hydrocarbons having 1 to 100, or even more than 100 carbon atoms, and typically includes paraffins, olefins and oxygenated products. Fischer Tropsch is a viable process to generate clean alternative hydrocarbon products, including Fischer-Tropsch waxes.
• Slack wax can be obtained from conventional petroleum derived feedstocks by either hydrocracking or by solvent refining of the lube oil fraction. Typically, slack wax is recovered from solvent dewaxing feedstocks prepared by one of these processes. Hydrocracking is usually preferred because hydrocracking will also reduce the nitrogen content to a low value. With slack wax derived from solvent refined oils, deoiling may be used to reduce the nitrogen content. Hydrotreating of the slack wax can be used to lower the nitrogen and sulfur content. Slack waxes posses a very high viscosity index, normally in the range of from about 140 to 200, depending on the oil content and the starting material from which the slack wax was prepared. Therefore, slack waxes are suitable for the preparation of base oils made from a waxy feed used in shock absorber fluids.
• the waxy feed has less than 25 ppm total combined nitrogen and sulfur.
• Nitrogen is measured by melting the waxy feed prior to oxidative combustion and chemiluminescence detection by ASTM D 4629-02. The test method is further described in US 6,503,956, incorporated herein.
• Sulfur is measured by melting the waxy feed prior to ultraviolet fluorescence by ASTM D 5453-00. The test method is further described in US 6,503,956, incorporated herein.
• Determination of normal paraffins (n-paraffins) in wax-containing samples is performed using a method that determines the content of individual C7 to C110 n-paraffins with a limit of detection of 0.1 wt%.
• the method used is gas chromatography, described later in this disclosure.
• Fischer-Tropsch derived base oils made from substantially paraffinic waxy feeds, and thus the shock absorber fluids comprising them, will be less expensive than lubricants made with other synthetic oils such as polyalphaolefins or esters.
• Fischer-Tropsch derived means that the product, fraction, or feed originates from or is produced at some stage by a Fischer-Tropsch process.
• Syncrude prepared from the Fischer-Tropsch process comprises a mixture of various solid, liquid, and gaseous hydrocarbons.
• Those Fischer-Tropsch products which boil within the range of lubricating base oil contain a high proportion of substantially paraffinic wax which makes them ideal candidates for processing into base oil. Accordingly, Fischer-Tropsch wax represents an excellent feed for preparing high quality base oils.
• Fischer-Tropsch wax is normally solid at room temperature and, consequently, displays poor low temperature properties, such as pour point and cloud point.
• Fischer-Tropsch derived base oils having excellent low temperature properties are prepared. Hydroisomerizing a waxy feed produced a product with increased branching and lower pour point.
• a general description of suitable hydroisomerization dewaxing processes may be found in US Patent Nos. 5,135,638 and 5,282,958; and US Patent Application 20050133409, incorporated herein.
• the hydroisomerization is achieved by contacting the waxy feed with a hydroisomerization catalyst in an isomerization zone under hydroisomerizing conditions.
• the hydroisomerization catalyst in some embodiments comprises a shape selective intermediate pore size molecular sieve, a noble metal hydrogenation component, and a refractory oxide support.
• the shape selective intermediate pore size molecular sieve may be selected from the group consisting of SAPO-11 , SAPO-31, SAPO-41 , SM-3, ZSM-22, ZSM-23, ZSM-35, ZSM-48, ZSM-57, SSZ-32, offretite, ferrierite, and combinations thereof.
• SAPO-11 , SM-3, SSZ-32, ZSM-23, ZSM-48, and combinations thereof are used in one embodiment.
• the noble metal hydrogenation component is platinum, palladium, or combinations thereof.
• the hydroisomerizing conditions depend on the waxy feed used, the hydroisomerization catalyst used, whether or not the catalyst is sulfided, the desired yield, and the desired properties of the base oil.
• the hydroisomerizing conditions include temperatures of 260 degrees C to about 413 degrees C (500 to about 775 degrees F), a total pressure of 15 to 3000 psig, and a hydrogen to feed ratio from about 2 to 30 MSCF/bbl, from about 4 to 20 MSCF/bbl (about 712.4 to about 3562 liter H 2 /liter oil), from about 4.5 or 5 to about 10 MSCF/bbl, or from about 5 to about 8 MSCF/bbl.
• the base oil produced by hydroisomerization dewaxing may be hydrofinished.
• the hydrofinishing may occur in one or more steps, either before or after fractionating of the base oil into one or more fractions.
• the hydrofinishing is intended to improve the oxidation stability, UV stability, and appearance of the product by removing aromatics, olefins, color bodies, and solvents.
• a general description of hydrofinishing may be found in US Patent Nos. 3,852,207 and 4,673,487, incorporated herein.
• the hydrofinishing step may be used to reduce the weight percent olefins in the base oil to less than 10, or even as low as less than 0.01.
• the hydrofinishing step may also be used to reduce the weight percent aromatics to less than 0.3, less than 0.1 , or even as low as less than 0.01.
• the base oil produced by hydroisomerization dewaxing may be treated with an adsorbent such as bauxite or clay to remove impurities and improve the color and biodegradability.
• the lubricating base oil is typically separated into fractions.
• one or more of the fractions will have a pour point less than 0°C, less than -9°C, less than -15°C, less than -2O°C, less than -30°C, or less than - 35 0 C. Pour point is measured by ASTM D 5950-02.
• the one or more fractions have a total weight percent of molecules with cycloparaffinic functionality greater than 5, 10, 20 or greater than or equal to 30.
• the one or more fractions have a ratio of weight percent molecules with monocycloparaffinic functionality to weight percent molecules with multicycloparaffinic functionality greater than 3, greater than 5, greater than 10, greater than 15, greater than 20, or even greater than 100.
• the lubricating base oil is optionally fractionated into different viscosity grades of base oil.
• the fractionating can be done at various stages of manufacture, including before hydroisomerization dewaxing, following hydroisomerization dewaxing, before hydrofinishing, or following hydrofinishing, for example.
• "different viscosity grades of base oil” is defined as two or more base oils differing in kinematic viscosity at 100 degrees C from each other by at least 0.5 mm 2 /s. Kinematic viscosity is measured using ASTM D 445-06. Fractionating is done using a vacuum distillation unit to yield cuts with pre selected boiling ranges. One of the fractions may be a distillation bottoms product.
• the base oil fractions have measurable quantities of unsaturated molecules measured by FIMS.
• the hydroisomerization dewaxing and fractionating conditions are tailored to produce one or more selected fractions of base oil having greater than 10 weight percent total molecules with cycloparaffinic functionality, for example greater than 20 weight percent, greater than 35 or greater than 40; and a viscosity index greater than 150.
• the one or more selected fractions of base oils will usually have less than 70 weight percent total molecules with cycloparaffinic functionality.
• the one or more selected fractions of base oil will additionally have a ratio of molecules with monocycloparaffinic functionality to molecules with multicycloparaffinic functionality greater than 2.1. In some embodiments there may be no molecules with multicycloparaffinic functionality, such that the ratio of molecules with monocycloparaffinic functionality to molecules with multicycloparaffinic functionality is greater than 100.
• the base oil fractions have less than 10 wt% or less than 5 wt% naphthenic carbon. In another embodiment the base oil fractions have between about 1 or 2 wt% and about 5 or 10 wt% naphthenic carbon. In one embodiment, the base oil fraction has a kinematic viscosity of 1.5 mm 2 /s to about 3.0 mm 2 /s at 100°C and 2-3 % naphthenic carbon.
• a kinematic viscosity of 1.8 mm 2 /s to about 3.5 mm 2 /s at 100°C and 2.5 - 4 % naphthenic carbon In a third embodiment, a kinematic viscosity of 3 mm 2 /s to about 6 mm 2 /s at 100°C and 2.7 - 5 % naphthenic carbon.
• Noack Volatility Factor 160-40(Kinematic Viscosity at 100°C).
• the base oil fraction has a kinematic viscosity at 100 0 C between 1.5 and 4.0 mm 2 /s.
• the plot of the Noack Volatility Factor is shown in FIG. 3.
• the kinematic viscosity at 100°C of the base oil fraction is between 2.4 and 3.8 mm 2 /s and the Noack volatility of the base oil fraction is less than an amount calculated by the equation: 900 x (kinematic viscosity at 100°C) -2.8 - 15.
• the plot of this alternative upper limit for Noack volatility is shown in FIG. 3.
• the viscosity index of the lubricating base oil fraction of the shock absorber fluid is high.
• the viscosity index of the base oil fraction is greater than 28 x Ln(Kinematic Viscosity at 100°C) + 80.
• an oil with a kinematic viscosity of 2.5 mm 2 /s at 100°C will have a viscosity index greater than 105, 115, or 120; and a 5 mm 2 /s oil will have a viscosity index greater than 125, 135, or 140.
• the plots of these three alternative lower limits for viscosity index are shown in FIG. 1.
• the lubricating base oil fraction has a pour point of less than -8°C; a kinematic viscosity at 100°C of at least 1.5 mm 2 /s; and a viscosity index greater than an amount calculated by the equation: 22 x Ln (Kinematic Viscosity at 100°C.) + 132.
• an oil with a kinematic viscosity of 2.5 mm 2 /s at 100°C will have a viscosity index greater than 152.
• Base oils with these properties are described in US Patent Publication US20050077208. A plot of this embodiment of the lower limit for viscosity index is shown in FIG. 2.
• the presence of predominantly cycloparaffinic molecules with monocycloparaffinic functionality in the base oil fractions provides excellent oxidation stability, low Noack volatility, as well as desired additive solubility and elastomer compatibility.
• the base oil fractions have a weight percent olefins less than 10, less than 5, less than 1 , and in other embodiments less than 0.5, less than 0.05, or less than 0.01. In some embodiments, the base oil fractions have a weight percent aromatics less than 0.1 , less than 0.05, or less than 0.02.
• the base oil fractions have a traction coefficient less than 0.015 or 0.011, when measured at a kinematic viscosity of 15 mm 2 /s and at a slide to roll ratio of 40 percent. Examples of these base oil fractions with low traction coefficients are taught in U.S. Patent Number 7,045,055 and U.S. Patent Application 11/400570, filed April 7, 2006. Shock absorber fluids made with base oil fractions having low traction coefficients give low wear and extended service life.
• the olefin and aromatics contents are significantly low in the lubricant base oil fraction of the lubricating oil
• Oxidator BN of the selected base oil fraction will be greater than 25 hours, such as greater than 35 hours or even greater than 40 hours.
• the Oxidator BN of the selected base oil fraction will typically be less than 70 hours.
• Oxidator BN is a convenient way to measure the oxidation stability of base oils.
• the Oxidator BN test is described by Stangeland et al. in U.S. Patent 3,852,207.
• the Oxidator BN test measures the resistance to oxidation by means of a Dornte-type oxygen absorption apparatus. See R. W. Dornte Oxidation of White Oils," Industrial and Engineering Chemistry, Vol. 28, page 26, 1936. Normally, the conditions are one atmosphere of pure oxygen at 340°F.
• the results are reported in hours to absorb 1000 ml of O2 by 100 g. of oil.
• 0.8 ml of catalyst is used per 100 grams of oil and an additive package is included in the oil.
• the catalyst is a mixture of soluble metal naphthenates in kerosene.
• the mixture of soluble metal naphthenates simulates the average metal analysis of used crankcase oil.
• the additive package is 80 millimoles of zinc bispolypropylenephenyldithio-phosphate per 100 grams of oil, or approximately 1.1 grams of OLOA 260.
• the Oxidator BN test measures the response of a lubricating base oil in a simulated application. High values, or long times to absorb one liter of oxygen, indicate good oxidation stability. Shock absorber fluid comprising a base oil fraction having good oxidation stability will also have improved oxidation stability.
• OLOATM is an acronym for Oronite Lubricating Oil Additive, which is a registered trademark of Chevron Oronite.
• the one or more lubricating base oil fractions will have excellent biodegradability. With suitable hydro-processing and/or adsorbent treatment they are readily biodegradable by the OECD 301 B Shake Flask Test (Modified Sturm Test). When the readily biodegradable base oil fractions are blended with suitable biodegradable additives, such as selected low-ash or ashless additives, the lubricants will provide rapid biodegradation of spills in sensitive areas with minimal non-biodegradable residue and will prevent costly environmental clean-up.
• suitable biodegradable additives such as selected low-ash or ashless additives
• the aniline point of a lubricating base oil is the temperature at which a mixture of aniline and oil separates.
• ASTM D 611-01 b is the method used to measure aniline point. It provides a rough indication of the solvency of the oil for materials which are in contact with the oil, such as additives and elastomers. The lower the aniline point the greater the solvency of the oil.
• the aniline point of the lubricating base oil will tend to vary depending on the kinematic viscosity of the lubricating base oil at 100°C in mm 2 /s.
• the aniline point of the lubricating base is less than a function of the kinematic viscosity at 100°C.
• the function for aniline point is expressed as follows: Aniline Point, °F ⁇ 36 x Ln (Kinematic Viscosity at 100°C) + 200.
• the aniline point of the shock absorber fluid is greater than 88 0 C, or greater than or equal to 95 0 C.
• Foam tendency and stability are measured by ASTM D 892-03.
• ASTM D 892- 03 measures the foaming characteristics of a lubricating base oil or finished lubricant at 24 degrees C and 93.5 degrees C. It provides a means of empirically rating the foaming tendency and stability of the foam.
• the test oil maintained at a temperature of 24 degrees C, is blown with air at a constant rate for 5 minutes then allowed to settle for 10 minutes.
• the volume of foam, in ml is measured at the end of both periods (sequence I).
• the foaming tendency is provided by the first measurement, the foam stability by the second measurement.
• the test is repeated using a new portion of the test oil at 93.5 degrees C (sequence II); however the settling time is reduced to one minute.
• shock absorber fluid has a much lower foaming tendency than typical shock absorber fluids. In some embodiments they have a sequence I foam tendency less than 50 ml; they have a sequence Il foam tendency less than 50 ml, or less than 30 ml; and in some embodiments they have a sequence III foam tendency less than 50 ml.
• shock absorber fluids are blended with little to no antifoam agent, typically less than 0.2 wt%. However, shock absorber fluids of a higher viscosity or additionally comprising other base oils may exhibit foaming. Examples of antifoam agents are silicone oils, polyacrylates, acrylic polymers, and fluorosilicones.
• the additives for use in base oils to provide functional fluids include additives selected from the group consisting of viscosity index improvers, pour point depressants, detergents, dispersants, fluidizing agents, friction modifiers, corrosion inhibitors, rust inhibitors, antioxidants, detergents, seal swell agents, antiwear additives, extreme pressure (EP) agents, thickeners, friction modifiers, colorants, color stabilizers, antifoam agents, corrosion inhibitors, rust inhibitors, seal swell agents, metal deactivators, deodorizers, demulsifiers, and mixtures thereof.
• an effective amount of at least one additive is blended with a base oil to make the functional fluid.
• An "effective amount" is an amount required to achieve a desired effect.
• the additives may be in the form of a lubricant additive package, which comprises several additives to provide a shock absorber fluid with desirable properties.
• Lubricant additive packages for use in base oils to provide shock absorber fluids include lubricant additive packages selected from the group consisting of viscosity index improvers, pour point depressants, detergent- inhibitor (Dl) packages, and mixtures thereof. VISCOSITY INDEX IMPROVERS
• Viscosity index improvers modify the viscometric characteristics of lubricants by reducing the rate of thinning with increasing temperature and the rate of thickening with low temperatures. Viscosity index improvers thereby provide enhanced performance at low and high temperatures. In many applications, viscosity index improvers are used in combination with detergent-inhibitor additive packages to provide a shock absorber fluid.
• the viscosity index improvers can be selected from the group consisting of olefin copolymers, co-polymers of ethylene and propylene, polyalkylacrylates, polyalkylmethacrylat.es, styrene esters, polyisobutylene, hydrogenated styrene- isoprene copolymers, star polymers, including those having tetrablock copolymer arms of hydrogenated polyisoprene-polybutadiene-polyisoprene with a block of polystyrene, or hydrogenated asymmetric radial polymers having molecules with a core composed of the remnant of a tetravalant silicon coupling agent, a plurality of rubbery arms comprising polymerized diene units and a block copolymer arm having at least one polymerized diene block and a polymerized monovinyl aromatic compound block, hydrogenated styrene- butadienes, and mixtures thereof.
• the viscosity index improver is an ethylene/a-olefin interpolymer as described in WO2006102146, wherein the ethylene/a-olefin interpolymer is a block copolymer having at least a hard block and at least a soft block.
• the soft block comprises a higher amount of comonomers than the hard block.
• the viscosity index improver is an acrylic acid ester polymer comprising a copolymer derived from 1-4C acrylic acid ester monomer, 12-14C acrylic acid ester monomer and 16-20C acrylic acid ester monomer, as described in US20060252660, wherein the copolymer has weight average molecular weight of 20,000-100,000 deltons, and contains 1 wt% or less of unreacted monomer.
• pour point depressants used in shock absorber fluids modify the wax crystal morphology such as to reduce interlocking of the wax crystals with consequent viscosity increase or gellation.
• pour point depressants are alkylated naphthalene and phenolic polymers, polymethacrylates, alkylated bicyclic aromatics, maleate/fumarate copolymer esters, methacrylate-vinyl pyrrolidone copolymers, styrene esters, polyfumerates, vinyl acetate-fumarate co-polymers, dialkyl esters of phthalate acid, ethylene vinyl acetate compolyers, and other mixed hydrocarbon polymers from commercial additive suppliers such as LUBRIZOL, the ETHYL Corporation, or ROHMAX, a Division of Degussa.
• a base oil pour point reducing blend component may be used.
• pour point reducing blend component refers to an isomerized waxy product with relatively high molecular weights and a specified degree of alkyl branching in the molecule, such that it reduces the pour point of lubricating base oil blends containing it. Examples of a pour point reducing blend component are disclosed in U.S. Patent Nos. 6,150,577 and 7,053,254, and Patent Publication No. US 2005-0247600 A1.
• a pour point reducing blend component can be: 1) an isomerized Fischer-Tropsch derived bottoms product; 2) a bottoms product prepared from an isomerized highly waxy mineral oil, or 3) an isomerized oil having a kinematic viscosity at 100°C of at least about 8 mm 2 /s made from polyethylene plastic.
• the 10 percent point of the boiling range of the pour point reducing blend component that is a vacuum distillation bottoms product is between about 850 °F - 1050°F (454 - 565 °C).
• the pour point reducing blend component is derived from either Fischer-Tropsch or petroleum products, having a boiling range above 950°F (510°C), and contains at least 50 percent by weight of paraffins.
• the pour point reducing blend component has a boiling range above 1050°F (565°C)
• the pour point reducing blend component is an isomerized petroleum derived base oil containing material having a boiling range above about 1050°F.
• the isomerized bottoms material is solvent dewaxed prior to being used as a pour point reducing blend component. The waxy product further separated during solvent dewaxing from the pour point reducing blend component were found to display excellent improved pour point depressing properties compared to the oily product recovered after the solvent dewaxing.
• the pour point reducing blend component is an isomerized oil having a kinematic viscosity at 100°C of at least about 8 mm 2 /s made from polyethylene plastic.
• the pour point reducing blend component is made from waste plastic.
• the pour point reducing blend component is made from steps comprising pyrolysis of polyethylene plastic, separating out a heavy fraction, hydrotreating the heavy fraction, catalytic isomerizing the hydrotreated heavy fraction, and collecting the pour point reducing blend component having a kinematic viscosity at 100°C of at least about 8 mm 2 /s.
• the pour point reducing blend component derived from polyethylene plastic and has a boiling range above 1050°F.
• the pour point reducing blend component has an average degree of branching in the molecules within the range of from 6.5 to 10 alkyl branches per 100 carbon atoms. In another embodiment, the pour point reducing blend component has an average molecular weight between 600 - 1100. In a third embodiment it has an average molecular weight between 700 - 1000.
• the pour point reducing blend component has a kinematic viscosity at 100°C of 8 - 30 mm 2 /s, with the 10% point of the boiling range of the bottoms falling between about 850 - 1050°F In yet another embodiment, the pour point reducing blend component has a kinematic viscosity at 100°C of 15- 20 mm 2 /s and a pour point of -8 to -12°C.
• the pour point reducing blend component is an isomerized oil having a kinematic viscosity at 100°C of at least about 8 mm 2 /s made from polyethylene plastic.
• the pour point reducing blend component is made from waste plastic.
• the pour point reducing blend component is made from steps comprising pyrolysis of polyethylene plastic, separating out a heavy fraction, hydrotreating the heavy fraction, catalytic isomerizing the hydrotreated heavy fraction, and collecting the pour point reducing blend component having a kinematic viscosity at 100°C of at least about 8 mm 2 /s.
• the pour point reducing blend component derived from polyethylene plastic has a boiling range above 1050°F (565°C), or even a boiling range above 1200°F (649°C).
• Detergent-inhibitor packages serve to suspend oil contaminants, as well as to prevent oxidation of the shock absorber fluids with the resultant formation of varnish and sludge deposits.
• the detergent-inhibitor (Dl) package useful in shock absorber fluids contains one or more conventional additives selected from the group consisting of dispersants, fluidizing agents, friction modifiers, corrosion inhibitors, rust inhibitors, antioxidants, detergents, seal swell agents, extreme pressure additives, antiwear additives, deodorizers, antifoam agents, demulsifiers, colorants, and color stabilizers.
• the detergent-inhibitor package is present in an amount of from 2 to 25 weight percent, based on the total weight of the shock absorber fluid composition.
• Detergent-inhibitor packages are readily available from additive suppliers such as LUBRIZOL, ETHYL, Oronite, and INFINEUM. A number of detergent-inhibitor additives are described in EP0978555A1.
• DISPERSANTS Dispersants are used in shock absorber fluids to disperse wear debris and products of lubricant degradation within the equipment being lubricated, such as in the power steering equipment or shock absorber.
• the ashless dispersants commonly used contain a lipophilic hydrocarbon group and a polar functional hydrophilic group.
• the polar functional group can be of the class of carboxylate, ester, amine, amide, imine, imide, hydroxyl, ether, epoxide, phosphorus, ester carboxyl, anhydride, or nitrile.
• the lipophilic group can be oligomeric or polymeric in nature, usually from 70 to 200 carbon atoms to ensure good oil solubility.
• Hydrocarbon polymers treated with various reagents to introduce polar functions include products prepared by treating polyolefins such as polyisobutene first with maleic anhydride, or phosphorus sulfide or chloride, or by thermal treatment, and then with reagents such as polyamine, amine, ethylene oxide, etc.
• shock absorber fluids include N-substituted polyisobutenyl succinimides and succinates, alkyl methacrylate-vinyl pyrrolidinone copolymers, alkyl methacrylate- dialkylaminoethyl methacrylate copolymers, alkylmethacrylate-polyethylene glycol methacrylate copolymers, and polystearamides.
• Some oil-based dispersants that are used in shock absorber fluids include dispersants from the chemical classes of alkylsuccinimide, succinate esters, high molecular weight amines, and Mannich base and phosphoric acid derivatives.
• polyisobutenyl succinimide-polyethylencpolyamine polyisobutenyl succinic ester
• polyisobutenyl hydroxybenzyl- polyethylencpolyamine bis-hydroxypropyl phosphorate.
• Commercial dispersants suitable for shock absorber fluid are for example, LUBRIZOL 890 (an ashless PIB succinimide), LUBRIZOL 6420 (a high molecular weight PIB succinimide), and ETHYL HITEC 646 (a non-boronated PIB succinimide).
• the dispersant may be combined with other additives used in the lubricant industry to form a dispersant-detergent (Dl) additive package for shock absorber fluid, e.g., LUBRIZOL 9677MX, and the whole Dl package can be used as the dispersing agent.
• Dl dispersant-detergent
• a surfactant or a mixture of surfactants with low HLB value typically less than or equal to 8
• nonionic preferably nonionic
• a mixture of nonionics and ionics may be used as the dispersants in the shock absorber fluid.
• the dispersants selected should be soluble or dispersible in the liquid medium or additive diluent oil.
• the dispersant can be in a range of up from 0.01 to 30 percent and all sub-ranges therebetween, for example in a range of from between 0.5 percent to 20 percent, a range of from between 1 to 15 percent, or in a range of from between 2 to 13 percent as active ingredient in the shock absorber fluid
• Fluidizing agents are sometimes used in shock absorber fluids.
• Suitable fluidizing agents include oil-soluble diesters.
• diesters include the adipates, azelates, and sebacates of C8-C13 alkanols (or mixtures thereof), and the phthalates of C4-C13 alkanols (or mixtures thereof).
• Mixtures of two or more different types of diesters e.g., dialkyl adipates and dialkyl azelates, etc. can also be used.
• esters which are used as fluidizing agents in shock absorber fluids are polyol esters such as EMERY 2918, 2939 and 2995 esters from the EMERY Group of Henkel Corporation and HATCOL 2926, 2970 and 2999.
• thickeners besides viscosity index improvers, which can be used in the shock absorber fluid include: acrylic polymers such as polyacrylic acid and sodium polyacrylate, high-molecular-weight polymers of ethylene oxide such as Polyox WSR from Union Carbide, cellulose compounds such as carboxymethylcellulose, polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), xanthan gums and guar gums, polysaccharides, alkanolamides, amine salts of polyamide such as DtSPARLON AQ series from King Industries, hydrophobically modified ethylene oxide urethane (e.g., ACRYSOL series from Rohmax), silicates, and fillers such as mica, silicas, cellulose, wood flour, clays (including organoclays) and clays, and resin polymers such as polyvinyl butyral resins, polyurethane resins, acrylic resins and epoxy resins.
• acrylic polymers such as polyacrylic acid and sodium polyacryl
• thickeners are polyisobutylene, high molecular weight complex ester, butyl rubber, olefin copolymers, styrene-diene polymer, polymethacrylate, styrene-ester, and ultra high viscosity PAO.
• An example of a high molecular weight complex ester is Priolube® 3986.
• an ultra high viscosity PAO may also be used in the formulation.
• an "ultra high viscosity PAO" has a kinematic viscosity between about 150 and 1 ,000 mm 2 /s or higher at 100 degrees C.
• One group of friction modifiers is comprised of the N-aliphatic hydrocarbyl- substituted diethanol amines in which the N-aliphatic hydrocarbyl-substituent is at least one straight chain aliphatic hydrocarbyl group free of acetylenic unsaturation and having in the range of about 14 to about 20 carbon atoms.
• Another group of friction modifiers is comprised of esters of fatty acids, for example CENWAXTM TGA-185 and glycerol esters of selected fatty acids such as UNIFLEXTM 1803, both made by Arizona Chemical.
• Friction modifiers will sometimes include a combination of at least one N- aliphatic hydrocarbyl-substituted diethanol amine and at least one N-aliphatic hydrocarbyl-substituted trimethylene diamine in which the N-aliphatic hydrocarbyl-substituent is at least one straight chain aliphatic hydrocarbyl group free of acetylenic unsaturation and having in the range of about 14 to about 20 carbon atoms. Further details concerning this friction modifier combination are set forth in U.S. Pat. Nos. 5.372,735 and 5,441,656.
• Another example of a mixture of friction modifiers is based on the combination of (i) at least one di(hydroxyalkyl) aliphatic tertiary amine in which the hydroxyalkyl groups, being the same or different, each contain from 2 to about 4 carbon atoms, and in which the aliphatic group is an acyclic hydrocarbyl group containing from about 10 to about 25 carbon atoms, and (ii) at least one hydroxyalkyl aliphatic imidazoline in which the hydroxyalkyl group contains from 2 to about 4 carbon atoms, and in which the aliphatic group is an acyclic hydrocarbyl group containing from about 10 to about 25 carbon atoms. Further details concerning this friction modifier system are found in U.S. Pat. No. 5,344,579.
• Corrosion inhibitors are another class of additives suitable for inclusion in shock absorber fluids.
• Such compounds include thiazoles, triazoles and thiadiazoles.
• Examples of such compounds include benzotriazole, tolyltriazole, octyltriazole, decyltriazole, dodecyltriazole, 2-mercapto benzothiazole, 2,5- dimercapto-1 ,3,4-thiadiazole, 2-mercapto-5-hydrocarbylthio-1 ,3,4-thiadiazoles, 2-mercapto-5- hydrocarbyldithio-1 ,3,4-thiadiazoles, 2,5-bis(hydrocarbylthio)- 1,3,4-thiadiazoles, and 2,5-bis(hydrocarbyldithio)-1 ,3,4-thiadiazoles.
• Corrosion inhibitors of these types that are available on the open market include Cobratec TT-100 and HITEC® 3
• Rust inhibitors comprise another type of inhibitor additive for use in this invention. Some rust inhibitors are also corrosion inhibitors. Examples of rust inhibitors useful in shock absorber fluids are monocarboxylic acids and polycarboxylic acids. Examples of suitable monocarboxylic acids are octanoic acid, decanoic acid and dodecanoic acid. Suitable polycarboxylic acids include dimer and trimer acids such as are produced from such acids as tall oil fatty acids, oleic acid, linoleic acid, or the like.
• rust inhibitor for use in shock absorber fluid is comprised of the alkenyl succinic acid and alkenyl succinic anhydride corrosion inhibitors such as, for example, tetrapropenylsuccinic acid, tetrapropenylsuccinic anhydride, tetradecenylsuccinic acid, tetradecenylsuccinic anhydride, hexadecenylsuccinic acid, hexadecenylsuccinic anhydride, and the like.
• Suitable rust or corrosion inhibitors include ether amines; acid phosphates; amines: polyethoxylated compounds such as ethoxylated amines, ethoxylated phenols, and ethoxylated alcohols; imidazolines; aminosuccinic acids or derivatives thereof, and the like. Materials of these types are available as articles of commerce. Mixtures of rust inhibitors can be used.
• ANTIOXIDANTS ANTIOXIDANTS
• Suitable antioxidants include phenolic antioxidants, aromatic amine antioxidants, sulfurized phenolic antioxidants, hindered phenolic antioxidants, molybdenum containing compounds, zinc dialkyldithiophosphates, and organic phosphites, among others. Mixtures of different types of antioxidants are often used.
• phenolic antioxidants include ionol derived hindered phenols, 2,6-di-tert-butylphenol, liquid mixtures of tertiary butylated phenols, 2,6-di-tert-butyl-4-methylphenol, 4,4'- methylenebis(2,6-di-tert-butylphenol), 2,2'-methylenebis(4-methyl-6-tert-butylphenol), mixed methylene-bridged polyalkyl phenols, 4,4'-thiobis(2-methyl-6-tert-butylphenol), and sterically hindered tertiary butylated phenols.
• N,N'-di-sec-butyl-p-phenylenediamine, 4- isopropylaminodiphenyl amine, phenyl-naphthyl amine, phenyl-naphthyl amine, styrenated diphenylamine, and ring-alkylated diphenylamines serve as examples of aromatic amine antioxidants.
• the antioxidant is a catalytic antioxidant comprising one or more oil soluble organo metallic compound(s) and/or organo metallic coordination complexes such as metal(s) or metal cation(s) having more than one oxidation state above the ground state complexed, bonded or associated with two or more anions, one or more bidentate or tridentate ligands and/or two or more anions and ligand(s), as described in US20060258549.
• seal swell agents useful in shock absorber fluids are described in US Patent Publication US20030119682A1 and US20070057226A1.
• seal swell agents are aryl esters, long chain alkyl ether, alkyl esters, vegetable based esters, sebacate esters, sulfolanes, substituted sulfolane, other sulfolane derivatives, phenates, adipates, glyceryl tri(acetoxystearate), epoxidized soybean oil, epoxidized linseed oil, N, n-butyl benzene sulfonamide, aliphatic polyurethane, polyester glutarate, triethylene glycol caprate/caprylate, dialkyl diester glutarate, monomeric, polymer , and epoxy plasticizers, phthalate plasticizers, such as dioctyl phthalate, dinonly phthalate or dihexylpthalate, or oxygen-, sulfur-,
• plasticizers which may be substituted for and/or used with the above plasticizers including glycerine, polyethylene glycol, dibutyl phthalate, and 2,2,4-trimethyl-1 ,3-pentanediol monoisobutyrate, and diisononyl phthalate all of which are soluble in a solvent carrier.
• seal swelling agents such as LUBRIZOL 730 can also be used.
• sulfur-containing antiwear and/or extreme pressure additives can be used in shock absorber fluids.
• examples include dihydrocarbyl polysulfides; sulfurized olefins; sulfurized fatty acid esters of both natural and synthetic origins; trithiones; sulfurized thienyl derivatives; sulfurized terpenes: sulfurized oligomers of C2-C8 monoolefins; and sulfurized Diels-Alder adducts such as those disclosed in U.S. reissue patent Re 27,331.
• Specific examples include sulfurized polyisobutene, sulfurized isobutylene, sulfurized diisobutylene, sulfurized triisobutylene, dicyclohexyl polysulfide, diphenyl polysulfide, dibenzyl polysulfide, dinonyl polysulfide, and mixtures of di-tert- butyl polysulfide such as mixtures of di-tert-butyl trisulfide, di-tert-butyl tetrasulfide and di-tert-butyl pentasulfide, among others.
• Combinations of such categories of sulfur-containing antiwear and/or extreme pressure agents can also be used, such as a combination of sulfurized isobutylene and di-tert-butyl trisulfide, a combination of sulfurized isobutylene and dinonyl trisulfide, a combination of sulfurized tall oil and dibenzyl polysulfide.
• a component which contains both phosphorus and sulfur in its chemical structure is deemed a phosphorus-containing antiwear and/or extreme pressure agent rather than a sulfur-containing antiwear and/or extreme pressure agent.
• phosphorus-containing oil-soluble antiwear and/or extreme pressure additives such as the oil-soluble organic phosphates, organic phosphites, organic phosphonates, organic phosphonites, etc., and their sulfur analogs.
• phosphorus-containing antiwear and/or extreme pressure additives that may be used in shock absorber fluids include those compounds that contain both phosphorus and nitrogen.
• Phosphorus-containing oil-soluble antiwear and/or extreme pressure additives useful in shock absorber fluids include those compounds taught in U.S. Patent Nos. 5,464,549; 5,500,140; and 5,573,696.
• phosphorus- and nitrogen-containing antiwear and/or extreme pressure additives which can be used in shock absorber fluids are the phosphorus- and nitrogen-containing compositions of the type described in G.B. 1 ,009,913; G.B. 1 ,009,914; U.S. 3,197,405 and/or U.S. 3,197,496.
• these compositions are formed by forming an acidic intermediate by the reaction of a hydroxy-substituted triester of a phosphorothioic acid with an inorganic phosphorus acid, phosphorus oxide or phosphorus halide, and neutralizing a substantial portion of said acidic intermediate with an amine or hydroxy-substituted amine.
• phosphorus- and nitrogen-containing antiwear and/or extreme pressure additive that may be used in shock absorber fluids include the amine salts of hydroxy-substituted phosphetanes or the amine salts of hydroxy-substituted thiophosphetanes and the amine salts of partial esters of phosphoric and thiophosphoric acids.
• antifoam agents examples include antifoam agents that when blended into the shock absorber fluid will exhibit spreading coefficients of at least 2 mN/m at both 24 degrees C and 93.5 degrees C.
• Various types of antifoam agents are taught in US 6, 090,758. When used, the antifoam agents should not significantly increase the air release time of the shock absorber fluid.
• suitable antifoam agents are high molecular weight polydimethyl siloxane, a type of silicone antifoam agent, acrylate antifoam agents (as they are less likely to adversely effect air release properties compared to lower molecular weight silicone antifoam agents), polydimethylsiloxanes and polyethylene glycol ethers and esters.
• Colorants or dyes are used to impart color or to fluoresce under particular types of light. Fluorescent dyes facilitate leak detection. Colored oils help distinguish between different lubricant products. Examples of these colorants or dyes are anthraquinones, azo compounds, triphenyl-methane, perylene dye, naphthalimide dye, and mixtures thereof. Particular types of fluorescent dyes are taught in U.S. Patent No. 6,165,384.
• Diluent oil is often used in the different types of additive packages to effectively suspend or dissolve the additives in a liquid medium.
• the maximum amount of diluent oil in all of the additive packages used to make the shock absorber fluid should be within 0 to 40 volume%.
• the diluent oil is an extra light hydrocarbon liquid derived from highly paraffinic wax, described in US20060201852A, wherein the diluent oil has a viscosity of between about 1.0 and 3.5 mm 2 /s at 100° C and a Noack volatility of less than 50 weight %, and also having greater than 3 weight % molecules with cycloparaffinic functionality and less than 0.30 weight percent aromatics.
• a method to use a shock absorber fluid comprising selecting a shock absorber fluid having an auto ignition temperature greater than 329 °C (625 °F) and a viscosity index greater than 28 x Ln(Kinematic Viscosity at 100°C) +80, wherein the shock absorber fluid comprises a base oil made from a waxy feed, providing the shock absorber fluid to a mechanical system, and transferring heat in the mechanical system from a heat source to a heat sink.
• Wt% boiling points are determined by ASTM D6352-04.
• Wt% Naphthenic Carbon by n-d-M ASTM D 3238-95(Reapproved 2005) is used to determine wt% naphthenic carbon by n-d-M, % C N .
• GC gas chromatography
• the waxy feed is melted to obtain a 0.1 g homogeneous sample.
• the sample is immediately dissolved in carbon disulfide to give a 2 wt% solution. If necessary, the solution is heated until visually clear and free of solids, and then injected into the GC.
• the methyl silicone column is heated using the following temperature program:
• the column then effectively separates, in the order of rising carbon number, the normal paraffins from the non-normal paraffins.
• a known reference standard is analyzed in the same manner to establish elution times of the specific normal-paraffin peaks.
• the standard is ASTM D2887 n-paraffin standard, purchased from a vendor (Agilent or Supelco), spiked with 5 wt% Polywax 500 polyethylene (purchased from Petrolite Corporation in Oklahoma). The standard is melted prior to injection. Historical data collected from the analysis of the reference standard also guarantees the resolving efficiency of the capillary column.
• normal paraffin peaks are well separated and easily identifiable from other hydrocarbon types present in the sample. Those peaks eluting outside the retention time of the normal paraffins are called non-normal paraffins.
• the total sample is integrated using baseline hold from start to end of run. N-paraffins are skimmed from the total area and are integrated from valley to valley. All peaks detected are normalized to 100%. EZChrom is used for the peak identification and calculation of results.
• the Wt% Olefins in the base oil is determined by proton-NMR by the following steps, A-D:
• the wt% olefins by proton NMR 100 times the number of double bonds times the number of hydrogens in a typical olefin molecule divided by the number of hydrogens in a typical test substance molecule.
• the wt% olefins by proton NMR calculation procedure, D works best when the % olefins result is low, less than about 15 weight percent.
• the olefins must be "conventional" olefins; i.e. a distributed mixture of those olefin types having hydrogens attached to the double bond carbons such as: alpha, vinylidene, cis, trans, and trisubstituted. These olefin types will have a detectable allylic to olefin integral ratio between 1 and about 2.5. When this ratio exceeds about 3, it indicates a higher percentage of tri or tetra substituted olefins are present and that different assumptions must be made to calculate the number of double bonds in the sample.
• Aromatics Measurement by HPLC-UV The method used to measure low levels of molecules with at least one aromatic function in the lubricant base oils uses a Hewlett Packard 1050 Series Quaternary Gradient High Performance Liquid Chromatography (HPLC) system coupled with a HP 1050 Diode-Array UV-Vis detector interfaced to an HP Chem-station. Identification of the individual aromatic classes in the highly saturated Base oils was made on the basis of their UV spectral pattern and their elution time. The amino column used for this analysis differentiates aromatic molecules largely on the basis of their ring- number (or more correctly, double-bond number). Thus, the single ring aromatic containing molecules elute first, followed by the polycyclic aromatics in order of increasing double bond number per molecule. For aromatics with similar double bond character, those with only alkyl substitution on the ring elute sooner than those with naphthenic substitution.
• HPLC Hewlett Packard 1050 Series Quaternary Gradient High Performance Liquid Chromatography
• Quantitation of the eluting aromatic compounds was made by integrating chromatograms made from wavelengths optimized for each general class of compounds over the appropriate retention time window for that aromatic. Retention time window limits for each aromatic class were determined by manually evaluating the individual absorbance spectra of eluting compounds at different times and assigning them to the appropriate aromatic class based on their qualitative similarity to model compound absorption spectra. With few exceptions, only five classes of aromatic compounds were observed in highly saturated API Group Il and III lubricant base oils.
• HPLC-UV is used for identifying these classes of aromatic compounds even at very low levels.
• Multi-ring aromatics typically absorb 10 to 200 times more strongly than single-ring aromatics.
• Alkyl-substitution also affected absorption by about 20%. Therefore, it is important to use HPLC to separate and identify the various species of aromatics and know how efficiently they absorb.
• alkyl-cyclohexylbenzene molecules in base oils exhibit a distinct peak absorbance at 272nm that corresponds to the same (forbidden) transition that unsubstituted tetralin model compounds do at 268nm.
• concentration of alkyl-1-ring aromatic naphthenes in base oil samples was calculated by assuming that its molar absorptivity response factor at 272nm was approximately equal to tetralin's molar absorptivity at 268nm, calculated from Beer's law plots. Weight percent concentrations of aromatics were calculated by assuming that the average molecular weight for each aromatic class was approximately equal to the average molecular weight for the whole base oil sample.
• This calibration method was further improved by isolating the 1-ring aromatics directly from the lubricant base oils via exhaustive HPLC chromatography. Calibrating directly with these aromatics eliminated the assumptions and uncertainties associated with the model compounds. As expected, the isolated aromatic sample had a lower response factor than the model compound because it was more highly substituted.
• the substituted benzene aromatics were separated from the bulk of the lubricant base oil using a Waters semi-preparative HPLC unit. 10 grams of sample was diluted 1 :1 in n-hexane and injected onto an amino-bonded silica column, a 5cm x 22.4mm ID guard, followed by two 25cm x 22.4mm ID columns of 8-12 micron amino- bonded silica particles, manufactured by Rainin Instruments, Emeryville, California, with n-hexane as the mobile phase at a flow rate of I8mls/min.
• the weight percent of all molecules with at least one aromatic function in the purified mono-aromatic standard was confirmed via long-duration carbon 13 NMR analysis. NMR was easier to calibrate than HPLC UV because it simply measured aromatic carbon so the response did not depend on the class of aromatics being analyzed. The NMR results were translated from % aromatic carbon to % aromatic molecules (to be consistent with HPLC-UV and D 2007) by knowing that 95-99% of the aromatics in highly saturated lubricant base oils were single-ring aromatics.
• the standard D 5292-99 method was modified to give a minimum carbon sensitivity of 500:1 (by ASTM standard practice E 386).
• A15-hour duration run on a 400-500 MHz NMR with a 10-12 mm Nalorac probe was used.
• Acorn PC integration software was used to define the shape of the baseline and consistently integrate.
• the carrier frequency was changed once during the run to avoid artifacts from imaging the aliphatic peak into the aromatic region. By taking spectra on either side of the carrier spectra, the resolution was improved significantly.
• the lubricant base oils were characterized by Field Ionization Mass Spectroscopy (FIMS) into alkanes and molecules with different numbers of unsaturations. The distribution of the molecules in the oil fractions was determined by FIMS.
• the samples were introduced via solid probe, preferably by placing a small amount (about 0.1 mg.) of the base oil to be tested in a glass capillary tube.
• the capillary tube was placed at the tip of a solids probe for a mass spectrometer, and the probe was heated from about 40 to 50°C up to 500 or 600X at a rate between 50°C and 100°C per minute in a mass spectrometer operating at about 10 -6 torr.
• the mass spectrometer was scanned from m/z 40 to m/z 1000 at a rate of 5 seconds per decade.
• the mass spectrometer used was a Micromass Time-of-Flight. Response factors for all compound types were assumed to be 1.0, such that weight percent was determined from area percent. The acquired mass spectra were summed to generate one "averaged" spectrum.
• the lubricant base oils were characterized by FIMS into alkanes and molecules with different numbers of unsaturations.
• the molecules with different numbers of unsaturations may be comprised of cycloparaffins, olefins, and aromatics. If aromatics were present in significant amounts in the lubricant base oil they would be identified in the FIMS analysis as 4-unsaturations. When olefins were present in significant amounts in the lubricant base oil they would be identified in the FIMS analysis as 1 -unsaturations.
• the total of the 1- unsaturations, 2-unsaturations, 3-unsaturations, 4-unsaturations, 5- unsaturations, and 6-unsaturations from the FIMS analysis, minus the wt% olefins by proton NMR, and minus the wt% aromatics by HPLC-UV is the total weight percent of molecules with cycloparaffinic functionality in the lubricant base oils. Note that if the aromatics content was not measured, it was assumed to be less than 0.1 wt% and not included in the calculation for total weight percent of molecules with cycloparaffinic functionality.
• Molecules with cycloparaffinic functionality mean any molecule that is, or contains as one or more substituents, a monocyclic or a fused multicyclic saturated hydrocarbon group.
• the cycloparaffinic group may be optionally substituted with one or more substituents.
• Representative examples include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, decahydronaphthalene, octahydropentalene, (pentadecan-6- yl)cyclohexane, 3,7,10-tricyclohexylpentadecane, decahydro-1-(pentadecan-6- yl)naphthalene, and the like.
• Molecules with monocycloparaffinic functionality mean any molecule that is a monocyclic saturated hydrocarbon group of three to seven ring carbons or any molecule that is substituted with a single monocyclic saturated hydrocarbon group of three to seven ring carbons.
• the cycloparaffinic group may be optionally substituted with one or more substituents. Representative examples include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, (pentadecan-6-yl) cyclohexane, and the like.
• Molecules with multicycloparaffinic functionality mean any molecule that is a fused multicyclic saturated hydrocarbon ring group of two or more fused rings, any molecule that is substituted with one or more fused multicyclic saturated hydrocarbon ring groups of two or more fused rings, or any molecule that is substituted with more than one monocyclic saturated hydrocarbon group of three to seven ring carbons.
• the fused multicyclic saturated hydrocarbon ring group in one embodiment is of two fused rings.
• the cycloparaffinic group may be optionally substituted with one or more substituents.
• Hydraulic Shock Absorber octahydropentalene, 3,7,10-tricyclohexylpentadecane, decahydro-1- (pentadecan-6-yl) naphthalene, and the like.
• Improved hydraulic shock absorbers are made and operated with the shock absorbers having improved performance disclosed herein.
• the shock absorbers are mounted on equipment, such as passenger cars, sport utility vehicles, or trucks.
• the shock absorbers with improved performance are also useful on racing cars, where demands on the shock absorber may be extreme.
• Two base oils were prepared by hydroisomerization dewaxing a Co-based Fischer-Tropsch wax and a Fe-based Fischer-Tropsch wax over a Pt/SAPO-11 catalyst at 1000 psi, 0.5-1.5 LHSV, and between 660-690 °C. They were subsequently hydrotreated to reduce the level of aromatics and olefins, then vacuum distilled into fractions.
• the FIMS analysis was conducted on a Micromass Time-of-Flight spectrophotometer.
• the emitter on the Micromass Time-of-Flight was a Carbotec 5um emitter designed for Fl operation.
• a constant flow of pentaflourochlorobenzene, used as lock mass, was delivered into the mass spectrometer via a thin capillary tube.
• the probe was heated from about 50°C up to 600°C at a rate of 100°C per minute.
• Test data on the two Fischer- Tropsch derived lubricant base oils are shown in Table II, below. Table Il
• SAFA, SAFB, and SAFC all have less than 4 wt% combined viscosity index improver and pour point depressant, with SAFC only having 0.4 wt%.
• shock absorber fluids were blended using the FT-XXL-2 and FT-XL-2 base oils described above.
• a comparison commercial formulation of shock absorber fluid made using petroleum derived naphthenic and paraffinic base oils was prepared (COMP SAFD).
• a second comparison blend of shock absorber fluid was blended using a petroleum derived paraffinic base oil (deeply dewaxed mineral oil) and similar additives as those used in the other shock absorber fluids (COMP SAFE). Viscosity index improver was added as needed to obtain kinematic viscosities at 100°C of about 2.4 mm 2 /s or greater.
• Table Vl The formulations and properties of the different shock absorber fluids are summarized in Table Vl, below.
• shock absorber fluids of this example showed exceptional viscometrics, highly desired high aniline points, excellent oxidation stability, improved 4-ball wear, good to excellent shear stability, low evaporation loss, high flash points, exceptionally fast air release, high flash points, and very low foaming. They required significantly lower amounts of additive package and friction modifier than the commercial shock absorber fluid, COMP SAFD. All three of the shock absorber fluids of this example had excellent low air release results considering that they only included base oils with average molecular weights less than 475 and with viscosity indexes less than 140.
• Stroke is defined as twice the amplitude of the oscillating movement of the dampers.
• the dampers were also submitted to a constant side load of 100 N by means of a compressed air piston to enable consistent wearing.
• the temperatures of the individual dampers were monitored by means of temperature sensors. The temperatures were monitored on a continuous basis and were automatically adjusted to maintain temperatures between 95 and 105°C by means of pressurized air flows.
• the dampers were adjusted to a damping force of 1150 N at a velocity of 0.22 m/s in rebound phase before testing to ensure consistency.
• the damping curve was measured before and after the endurance test, and the peak area increase was calculated.
• the quality of the oil was evaluated and the hardware of the damper was checked for wear. The duration of the test was 280 hours and 1 ,008,000 cycles.

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