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
  • C10M107/00—Lubricating compositions characterised by the base-material being a macromolecular compound
  • C10M107/02—Hydrocarbon polymers; Hydrocarbon polymers modified by oxidation
  • C10M107/10—Hydrocarbon polymers; Hydrocarbon polymers modified by oxidation containing aliphatic monomer having more than 4 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
  • C10M111/00—Lubrication compositions characterised by the base-material being a mixture of two or more compounds covered by more than one of the main groups C10M101/00 - C10M109/00, each of these compounds being essential
  • C10M111/04—Lubrication compositions characterised by the base-material being a mixture of two or more compounds covered by more than one of the main groups C10M101/00 - C10M109/00, each of these compounds being essential at least one of them being a macromolecular organic compound
• • 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
  • C10M2203/00—Organic non-macromolecular hydrocarbon compounds and hydrocarbon fractions as ingredients in lubricant compositions
  • C10M2203/06—Well-defined aromatic compounds
  • C10M2203/065—Well-defined aromatic compounds 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
  • 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
  • C10M2205/0285—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 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
  • C10M2207/00—Organic non-macromolecular hydrocarbon compounds containing hydrogen, carbon and oxygen as ingredients in lubricant compositions
  • C10M2207/28—Esters
  • C10M2207/282—Esters of (cyclo)aliphatic oolycarboxylic acids
  • C10M2207/2825—Esters of (cyclo)aliphatic oolycarboxylic acids 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
  • C10M2207/00—Organic non-macromolecular hydrocarbon compounds containing hydrogen, carbon and oxygen as ingredients in lubricant compositions
  • C10M2207/28—Esters
  • C10M2207/283—Esters of polyhydroxy compounds
  • C10M2207/2835—Esters of polyhydroxy compounds 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
  • C10M2207/00—Organic non-macromolecular hydrocarbon compounds containing hydrogen, carbon and oxygen as ingredients in lubricant compositions
  • C10M2207/28—Esters
  • C10M2207/285—Esters of aromatic polycarboxylic acids
  • C10M2207/2855—Esters of aromatic polycarboxylic acids used as base material
• • 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
  • C10N2030/68—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
  • C10N2040/04—Oil-bath; Gear-boxes; Automatic transmissions; Traction drives

Definitions

• the present invention relates to oil compositions and processes for making the same.
• the present invention relates to shear-stable lubricating oil compositions comprising a hydrocarbon base stock and a co-base stock or an additive.
• the present invention is useful, e.g., in making lubricant base stock blends with enhanced shear stability particularly suitable for use as gear box oils or other oils subject to repeated high shear stress during normal use.
• Lubricants in commercial use today are prepared from a variety of natural and synthetic base stocks admixed with various additive packages and solvents depending upon their intended application.
• the base stocks can include, e.g., Groups I, II and III mineral oils, gas-to-liquid base oils (GTL), Group IV polyalpha-olefins (PAO) including but not limited to PAOs made by using metallocene catalysts (mPAOs), Group V alkylated aromatics (AA) which include but are not limited to alkylated naphthalenes (ANs), silicone oils, phosphate esters, diesters, polyol esters, and the like.
• GTL gas-to-liquid base oils
• PAO Group IV polyalpha-olefins
• mPAOs metallocene catalysts
• AA alkylated aromatics
• ANs alkylated naphthalenes
• silicone oils phosphate esters, diesters, polyol esters, and the like
• Shear stability of the lubricating oil composition affects the oil drain life of the lubricating oil composition, especially those experiencing high-shear stress events during normal use such as gear box oils. Oxidative degradation of lubricating oil composition can lead to damage of metal machinery in which the lubricating oil composition is used. Such degradation may result in deposits on metal surfaces, the presence of sludge, or a viscosity decrease or change in the lubricating oil composition. For gear box oils, significant loss of viscosity during life of the oil can lead to reduced efficacy in lubrication, and hence premature wear and failure of the gears.
• the kinematic viscosity of a lubricating oil composition is partly related to the antioxidation performance and degree of oxidation of the lubricating oil composition.
• a lubricating oil composition being used in machinery has experienced oxidative degradation when the kinematic viscosity of lubricating oil composition reaches a certain level, and the lubricating oil composition needs to be replaced at that level. Improving the oxidation stability and antioxidation performance of the lubricating oil composition improves the oil drain life by increasing the amount of time the lubricating oil composition can be used before being replaced.
• Various approaches are used to improve the antioxidation performance and extend the oil drain life of Group IV/Group V lubricating oil compositions. The approaches typically involve increasing the antioxidant additive concentrations of the lubricating oil composition.
• US 2013/210996 discloses a PAO having a kinematic viscosity at 100°C of 135 cSt or greater that is derived from not more than 10 mol% ethylene and characterized by a high shear stability demonstrated by, after being subjected to twenty hours of a taper roller bearing testing, having a kinematic viscosity loss of less than 9%.
• the PAO comprises no more than 5.0 wt% of the polymer having molecular weight of greater than 45,000.
• a low concentration of large PAO molecules e.g., those having molecular weight of at least 45,000
• PAO base stock characterized by a low kinematic viscosity loss after severe shear stability tests.
• the above reference is primarily concerned with the shear stability of a single base stock material put into a lubricant oil composition.
• a first aspect of the present invention relates to oil composition
• oil composition comprising a first component and a second component differing from the first component, and free of a third component.
• the first component is a base stock comprising multiple molecules of a first type each having multiple pendant groups, where (i) the average pendant group length of the longest 5%, by mole, of the pendant groups of all of the molecules of the first type have an average pendant group length of Lpg(5%), where Lpg(5%) > 5.0; and (ii) a portion of the molecules of the first type have molecular weight greater than or equal to 20,000.
• the second component comprises multiple molecules of a second type each of which individually is capable of adjoining no more than one molecule of the first type via van der Waals force between straight carbon chains to form a stable first complex structure.
• the first complex structures may comprise a first heavy fraction thereof having an equivalent molecular weight of at least 45,000.
• the third component comprises molecules of a third type each comprising two terminal carbon chains, where (a) the number average molecular weight of the third component is no greater than 2,000; and (b) the two terminal carbon chains have chain lengths equal to or greater than 5.0 and do not share a common carbon atom.
• a single molecule of the third type is capable of adjoining two molecules of the first type via van der Waals force between the pendant groups of the molecules of the first type and the two terminal carbon chains in the single molecule of the third type to form a second complex structure.
• the second complex structures may comprise a second heavy fraction thereof having an equivalent molecular weight of at least 45,000.
• a second aspect of the present invention relates to process for making the above oil composition.
• FIG. 1 is a chart showing shear loss (SSI 92) of a series of oil compositions comprising multiple different types of base stocks at different concentrations.
• a "lubricant” refers to a substance that can be introduced between two or more moving surfaces and lower the level of friction between two adjacent surfaces moving relative to each other.
• a lubricant “base stock” is a material, typically a fluid at the operating temperature of the lubricant, used to formulate a lubricant by admixing it with other components.
• base stocks suitable in lubricants include API Group I, Group II, Group III, Group IV, Group V and Group VI base stocks.
• Fluids derived from Fischer-Tropsch process or Gas-to-Liquid (“GTL”) processes are examples of synthetic base stocks useful for making modern lubricants. GTL base stocks and processes for making them can be found in, e.g., WO 2005/121280 Al and U.S. Patent Nos. 7,344,631 ; 6,846,778; 7,241,375; 7,053,254.
• the shear stability of an oil is measured by using the KRL Tapered Roller Bearing Test (CEC L45-A99). Shear stability at 20 hours, 100 hours, and 192 hours may be measured, and reported as SS20, SSlOO, and SSI 92 (as percentages of viscosity loss), respectively. This test is especially useful for determining the amount of shear viscosity loss resulting from the high molecular weight components contained in the oil composition.
• the length of a pendant group or a side chain group means the total number of carbon atoms in a carbon chain starting from the first carbon atom therein directly bonded to a carbon backbone (e.g., in the case of a PAO molecule) or a nucleus (e.g., in the case of an alkyl naphthalene molecule) or a heteroatom (e.g., in the case of an ester molecule) of the molecule in question, and ending with the final carbon atom therein connected to no more than one carbon atom, without taking into consideration of any substituents on the chain.
• a carbon backbone e.g., in the case of a PAO molecule
• a nucleus e.g., in the case of an alkyl naphthalene molecule
• a heteroatom e.g., in the case of an ester molecule
• the pendant group or the side chain group is free of substituents comprising more than 2 carbon atoms (or more than 1 carbon atom), or is free of any substituent.
• the length of a terminal carbon chain means the total number of carbon atoms in a carbon chain starting from the terminal carbon atom therein and ending at any arbitrary non-terminal carbon atom in the molecule in question, without taking into consideration of any substituents on the chain.
• a terminal carbon atom is a carbon atom that is connected to one carbon atom and three hydrogen atoms.
• the terminal carbon chain is free of substituents comprising more than 2 carbon atoms (or more than 1 carbon atom), or is free of any substituent.
• a molecule may comprise two or more terminal carbon chains that do not share a common carbon atom.
• the two chains are said to extend in directions that form an angle theta.
• Each terminal carbon chain is said to have an axis assuming that the molecule takes the conformation with the lowest energy at 25°C, which is a hypothetical straight line that has the least total squares of distances to all of the carbon atoms in the terminal carbon chain in question.
• the two chains are said to form an angle theta of 0°.
• the two chains When parallel and the directions from the terminal to the non-terminal carbon atoms along the axes in the two chains are opposite to each other, the two chains are said to form an angle theta of 180°.
• the two axes When non-parallel and extending from the terminal carbon atom ends to the non-terminal carbon atom ends, the two axes form an angle that is smaller than 180°, which is regarded as the angle theta between the two chains.
• the unit of all molecular weight data is g-mol "1 .
• the "equivalent molecular weight” is the total molar mass of a complex structure formed by multiple molecular components via van der Waals force between parts of the molecular components.
• Molecular weight of oligomer or polymer materials (including conventional, non-metallocene-catalyzed and metallocene-catalyzed PAO materials) in the present disclosure are measured by using Gel Permeation Chromatography (GPC) equipped with a multiple-channel band filter based Infrared detector ensemble IR5 (GPC-IR).
• GPC Gel Permeation Chromatography
• IR5 Infrared detector ensemble IR5
• Carbon- 13 NMR ( 1 C-NMR) is used to determine tacticity of the PAOs of the present invention.
• Carbon-13 NMR can be used to determine the concentration of the triads, denoted (m,m)-triads (i.e., meso, meso), (m,r)- (i.e., meso, racemic) and (r,r)- (i.e., racemic, racemic) triads, respectively.
• concentrations of these triads defines whether the polymer is isotactic, atactic or syndiotactic.
• the concentration of the (m,m)- triads in mol% is recorded as the isotacticity of the PAO material.
• Spectra for a PAO sample are acquired in the following manner. Approximately 100-1000 mg of the PAO sample is dissolved in 2-3 ml of chloroform-d for 1 C-NMR analysis. The samples are run with a 60 second delay and 90° pulse with at least 512 transients. The tacticity was calculated using the peak around 35 ppm (CH 2 peak next to the branch point). Analysis of the spectra is performed according to the paper by Kim, I.; Zhou, J.-M.; and Chung, H. Journal of Polymer Science: Part A: Polymer Chemistry 2000, 38 1687-1697.
• the calculation of tacticity is mm*100/(mm+mr+rr) for the molar percentages of (m,m)-triads, mr* 100/(mm+mr+rr) for the molar percentages of (m,r)-triads, and rr*100/(mm+mr+rr) for the molar percentages of (r,r)-triads.
• the (m,m)-triads correspond to 35.5 - 34.55 ppm, the (m,r)-triads to 34.55 - 34.1 ppm, and the (r,r)-triads to 34.1 - 33.2 ppm.
• the present invention concerns with an oil composition (preferably a lubricating oil composition) comprising a first component and a second component, but free of a third component.
• an oil composition preferably a lubricating oil composition
• Each of these three components can be a base stock, a co-base stock, or an additive component.
• the molecules of these components desirably form a substantially homogeneous mixture such as a solution, where they interact with each other via forces such as ionic bonds, covalent bonds, hydrogen bonds, van der Waals force, and the like.
• the interaction of the molecules can impart many desirable properties to the mixture, e.g., enhanced performances in oxidation stability, thermal stability, rust inhibition, performance, viscosity index, anti-wear, and the like.
• the first component of the oil component of the present invention can be an oil base stock, a blend of multiple oil base stocks, an additive component typical of an oil composition, or the like.
• the first component comprises multiple molecules, which may be the same or different, each having multiple pendant groups on the structures thereof.
• a preferred, non-limiting example of the first component is a Group IV PAO base stock useful in lubricating oil compositions.
• Other base stocks, such as Group I, II, III, or V base stocks, may form a part or the entirety of the first component.
• PAOs are oligomeric or polymeric molecules produced from the polymerization reactions of alpha-olefin monomer molecules in the presence of a catalyst system, optionally further hydrogenated to remove residual carbon-carbon double bonds therein.
• Each PAO molecule has a carbon chain with the largest number of carbon atoms, which is designated the carbon backbone of the molecule. Any group attached to the carbon backbone other than to the carbon atoms at the very ends thereof is defined as a pendant group. The number of carbon atoms in the longest carbon chain in each pendant group is defined as the length of the pendant group.
• the backbone typically comprises the carbon atoms derived from the carbon- carbon double bonds in the monomer molecules participating in the polymerization reactions, and additional carbon atoms from monomer molecules that form the two ends of the backbone.
• a typical, hydrogenated PAO molecule can be represented by the following formula (F-l):
• R , R , R each of R" and R , R°, and R independently represents a hydrogen or a substituted or unsubstituted hydrocarbyl (preferably an alkyl) group, and n is a non-negative integer corresponding to the degree of polymerization.
• n 0
• (F-1) represents a dimer produced from the reaction of two monomer molecules after a single addition reaction between two carbon-carbon double bonds.
• (F-1) represents a molecule produced from the reactions of m+2 monomer molecules after m steps of addition reactions between two carbon-carbon double bonds.
• (F-1) represents a trimer produced from the reactions of three monomer molecules after two steps of addition reactions between two carbon-carbon double bonds.
• R 2 , R 3 , each of R 4 and R 5 , and R 6 which can be substituted or unsubstituted hydrocarbyl (preferably alkyl) groups, are pendant groups (if not hydrogen).
• R , R , R , all R and R , R , and R would be hydrogen
• R , R , and R would be a methyl, and about half of groups R , R , R , all R and R 5 , R 6 , and R 7 would be hydrocarbyl groups introduced from the alpha-olefin monomer molecules.
• the longest 5%, 10%, 20%, 40%, 50%, and 100% of the pendant groups have average pendant group length of Lpg(5%) of 8, Lpg(10%) of 8, Lpg(20%) of 8, Lpg(50%) of 8, and Lpg(100%) of 7.22, respectively.
• the longest 5%, 10%, 20%, 40%, 50%, and 100% of the pendant groups have average pendant group lengths of Lpg(5%) of 7, Lpg(10%) of 7, Lpg(20%) of 7, Lpg(50%) of 6.3, and Lpg(100%) of 3.67, respectively.
• one skilled in the art can determine the Lpg(5%), Lpg(10%), Lpg(20%), Lpg(50%), and Lpg(100%) values of a given PAO base stock material by using separation and characterization techniques available to polymer chemists. For example, gas chromatography/mass spectroscopy machines equipped with boiling point column separator can be used to separate and identify individual chemical species and fractions; and standard characterization methods such as NMR, IR, and UV spectroscopy can be used to further confirm the structures.
• PAO base stocks useful for the oil composition of the present invention may be a homopolymer made from a single alpha-olefin monomer or a copolymer made from a combination of two or more alpha-olefin monomers.
• Preferable PAO base stocks useful for the oil composition of the present invention are produced from an alpha-olefin feed comprising one or more alpha-olefin monomers having an average number of carbon atoms in the longest carbon chain thereof in a range from Ncl to Nc2, where Ncl and Nc2 can be, e.g., 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 10.5, 11.0, 11.5, 12.0, 12.5, 13.0, 13.5, 14.0, 14.5, 15.0, 15.5, or 16.0, as long as Ncl ⁇ Nc2.
• the "alpha-olefin feed” may be supplied to the polymerization reactor continuously or batch- wise.
• Each of the alpha-olefin monomer may comprise from 4 to 32 carbon atoms in the longest carbon chain therein.
• at least one of the alpha-olefin monomer is a linear alpha-olefin (LAO).
• LAO monomers have even number of carbon atoms.
• Non-limiting examples of the LAOs include but are not limited to 1-butene, 1-pentene, 1- hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1- tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1- eicosene, 1-heneicosene, 1-docosene, 1-tricosene, 1-tetracosene in yet another embodiment.
• Preferred LAO feeds are 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1- hexadecene and 1-octadecene.
• the alpha-olefin feed comprises ethylene at a concentration not higher than 1.5 wt% based on the total weight of the alpha-olefin feed.
• the alpha-olefin feed is essentially free of ethylene.
• Examples of preferred LAO mixtures as monomers for making the PAO useful in the oil composition of the present invention include, but are not limited to: C6/C8; C6/C10; C6/C12; C6/C14; C6/C16; C6/C8/C10; C6/C8/C12; C6/C8/C14; C6/C8/C16; C8/C10; C8/C12; C8/C14; C8/C16; C8/C10/C12; C8/C10/C14; C8/C10/C16; C10/C12; C10/C14; C10/C16; C10/C12/C14; C10/C12/C14; C10/C12/C16; and the like.
• the alpha-olefin monomer molecules react with components in or intermediates formed from the catalyst system and/or each other, resulting in the formation of covalent bonds between carbon atoms of the carbon-carbon double bonds of the monomer molecules, and eventually, an oligomer or polymer formed from multiple monomer molecules.
• the catalyst system may comprise a single compound or material, or multiple compounds or materials.
• the catalytic effect may be provided by a component in the catalyst system per se, or by an intermediary formed from reaction(s) between components in the catalyst system.
• the catalyst system may be a conventional catalyst based on a Lewis acid such as BF 3 or AICI 3 , or a Friedel-Crafts catalyst.
• the carbon-carbon double bonds in some of the olefin molecules are activated by the catalytically active agent, which subsequently react with the carbon-carbon double bonds of other monomer molecules. It is known that the thus activated monomer and/or oligomers may isomerize, leading to a net effect of the shifting or migration of the carbon-carbon double bonds and the formation of multiple short-chain pendant groups, such as methyl, ethyl, propyl, and the like, on the carbon backbone of the final oligomer or polymer macromolecules. Therefore, the average pendant group length of PAOs made by using such conventional Lewis acid-based catalysts can be relatively low.
• the catalyst system may comprise a non-metallocene Ziegler-Natta catalyst.
• the catalyst system may comprise a metal oxide supported on an inert material, e.g., chromium oxide supported on silica.
• Such catalyst system and use thereof in the process for making PAOs are disclosed in, e.g., U.S. Patent Nos. 4,827,073 (Wu); 4,827,064 (Wu); 4,967,032 (Ho et al); 4,926,004 (Pelrine et al); and 4,914,254 (Pelrine), the relevant portions thereof are incorporated herein by reference in their entirety.
• the catalyst system comprises a metallocene compound and an activator and/or co-catalyst.
• a metallocene catalyst system and method for making metallocene mPAOs using such catalyst systems are disclosed in, e.g., WO 2009/148685 Al, the content of which is incorporated herein by reference in its entirety.
• PAO base stocks made by using metallocene catalysts or supported chromium oxide catalysts are preferred, assuming the same monomer(s) is used.
• the PAO base stock comprises a plurality of oligomeric and/or polymeric PAO molecules, which may be the same or different.
• Each PAO molecule comprises a plurality of pendant groups, which may be the same or different, and the longest 5%, 10%, 20%, 40%, 50%, and 100% of the pendant groups of all of the molecules of the PAO base stock have an average pendent group length of Lpg(5%), Lpg(10%), Lpg(20%), Lpg(40%), Lpg(50%), and Lpg(100%), respectively. It is preferred that at least one of the following conditions are met:
• al and a2 can be, independently, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 10.5, 11.0, 11.5, or 12.0, as long as al ⁇ a2;
• bl ⁇ Lpg(10%) ⁇ b2 where bl and b2 can be, independently, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 10.5, 11.0, 11.5, or 12.0, as long as bl ⁇ b2;
• fl ⁇ Lpg(100%) ⁇ f2 where fl and f2 can be, independently, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, or 9.0, as long as fl ⁇ f2.
• At least 60% of the pendent groups on the PAO molecules in the PAO base stock are straight chain alkyls having at least 6 carbon atoms.
• at least 90% of the pendent groups on the PAO molecules in the PAO base stock are straight chain alkyls having at least 6 carbon atoms.
• at least 60% of the pendent groups on the PAO molecules in the PAO base stock are straight chain alkyls having at least 8 carbon atoms.
• at least 90% of the pendent groups on the PAO molecules in the PAO base stock are straight chain alkyls having at least 8 carbon atoms.
• the PAO base stock useful in the present invention may have various levels of regio-regularity.
• each PAO molecule may be substantially atactic, isotactic, or syndiotactic.
• the PAO base stock can be a mixture of different molecules, each of which can be atactic, isotactic, or syndiotactic.
• regio-regular PAO molecules, especially the isotactic ones due to the regular distribution of the pendant groups, especially the longer ones, tend to align better with the AA base stock molecules, as discussed below, and therefore preferred.
• PAO base stock molecules are regio-regular. It is further preferred that at least 50%, or 60%, or 70%, or 80%, or 90%, or even 95%, by mole, of the PAO base stock molecules are isotactic.
• PAO base stocks made by using metallocene catalysts can have such high regio-regularity (syndiotacticity or isotacticity), and therefore are preferred.
• a metallocene-based catalyst system can be used to make PAO molecules with over 70%, 75%, 80%, 85%, 90%, 95%, or even substantially 100% isotacticity.
• the PAO base stock useful for the present invention can have various viscosity.
• it may have a KV100 in a range from 1 to 5000 cSt, such as 1 to 3000 cSt, 2 to 2000 cSt, 2 to 1000 cSt, 2 to 800 cSt, 2 to 600 cSt, 2 to 500 cSt, 2 to 400 cSt, 2 to 300 cSt, 2 to 200 cSt, or 5 to 100 cSt.
• the exact viscosity of the PAO base stock can be controlled by, e.g., monomer used, polymerization temperature, polymerization residence time, catalyst used, concentration of catalyst used, distillation and separation conditions, and mixing multiple PAO base stocks with different viscosity.
• the PAO base stock used in the oil composition of the present invention has a bromine number in a range from Nb(PAO)l to Nb(PAO)2, where Nb(PAO)l and Nb(PAO)2 can be, independently, 0, 0.2, 0.4, 0.5, 0.6, 0.8, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, as long as Nb(PAO)l ⁇ Nb(PAO)2.
• the PAO used in the oil composition of the present invention has been subjected to a step of hydrogenation where the PAO has been in contact with a H2- containing atmosphere in the presence of a hydrogenation catalyst, such as one containing Co, Ni, Ru, Rh, Ir, Pt, and combinations thereof, such that at least a portion of the residual carbon-carbon double bonds present on the PAO molecules become saturated.
• a hydrogenation catalyst such as one containing Co, Ni, Ru, Rh, Ir, Pt, and combinations thereof, such that at least a portion of the residual carbon-carbon double bonds present on the PAO molecules become saturated.
• PAO base stocks useful for the oil composition of the present invention include, but are not limited to: SpectraSynTM synthetic non-metallocene PAO base stocks, SpectraSyn UltraTM series chromium oxide-based PAO base stocks, and SpectraSyn EliteTM series mPAO base stocks, all available from ExxonMobil Chemical Company located at Houston, Texas, U.S.A.
• Molecular structures of exemplary mPAO made from a mixture of 1-octene and 1- dodecene alpha-olefin monomers at a molar ratio of 4: 1 can be schematically represented as follows, where n can be any integer.
• the two CIO pendant groups are shown to be next to each other. In real molecules, they may be randomly distributed among all of the pendant groups.
• the structure shows 100% isotacticity, i.e., 100 mol% of (m,m)-triads in the structure. In real molecules, a small fraction may be (m,r) or (r,r) triads. Nonetheless, the highly regular pendant groups can extend to form a substantially straight chain in a solution, and interact with other long straight carbon chains from other mPAO molecules, co-base stock molecules, or additive molecules.
• the second component in the oil compositions of the present invention contrary to the third component, comprises multiple molecules of the second type that are capable of adjoining no more than one molecule of the first type via van der Waals force to form a stable complex structure.
• the second type component may comprise any Group I, II, III, IV, or V base stocks and additive components for lubricating oil compositions.
• the second component may comprise, in part or in whole, a PAO base stock or an AA base stock described above or below in connection with the first component or the third component.
• a molecule of the second component may comprise two terminal carbon chains such as long-chain alkyl groups that are substantially sterically hindered, such that only one of them may align with a pendant group of a molecule of the first type described above to form a complex structure via van der Waals force. Where the angle theta between the two terminal carbon chains is no more than 45°, the steric hindrance is so severe that one can consider the molecule to be substantially incapable of adjoining two molecules of the first type through interaction with two pendant groups of the two molecules of the first type via van der Waals force.
• the second component may comprise just one straight long-chain alkyl group on its molecular s (F-4).
• PAO molecules though typically containing two or more long straight carbon chains, tend not to form strong complex structures with each other via van der Waals force between the carbon chains. Without intending to be bound by a particular theory, this is believed to be due to the relatively large molecular sweep volume, and therefore inefficient and relatively weak coupling between the molecules. Therefore, PAO base stocks are preferred for the second component in the oil composition of the present invention.
• the molecules of the second type contained in the second component desirably have a number average molecular weight of no more than 2000, preferably no more than 1500, 1,000, 800, 600, or even 500. Small molecules of the second type are less likely to interact with molecules of the first type to form shearable complex structures having a large equivalent molecular weight.
• a molecule of the second type of the second component comprises one or more terminal carbon chain having at least 5 carbon atoms
• multiple such molecules of the second type may interact with multiple pendant groups of a single molecule of the first type to form a large first complex structure.
• the first complex structure may contain sufficient number of molecules of the second type to reach a large equivalent molecular weight, such as at least 30,000, 40,000, 45,000, 50,000, 55,000, or even 60,000, which may become shearable, akin to the second complex structure that may be formed between two molecules of the first type and a single molecule of the third type described below.
• the oil composition of the present invention is advantageously free of the third component described below.
• free of the third component is meant comprising the third component at a total concentration of at most 3 wt%, 2 wt%, 1 wt%, 0.5 wt%, 0.1 wt%, 0.05 wt%, or 0.01 wt%), based on the total weight of the oil composition.
• the third component comprises multiple molecules of the third type each comprising at least two terminal carbon chains that do not share a common carbon atom, wherein at least two of the terminal carbon chains have chain lengths equal to or greater than 5.0.
• terminal carbon chain is meant a carbon chain that ends with a carbon atom that is not connected to more than one carbon.
• the at least two terminal carbon chains are each capable of forming sufficiently strong bonding with pending groups of two or more separate molecules of the first type, thereby forming a complex structures comprising at least two molecules of the first type and at least one molecule of the third type. Desirably both of the terminal carbon chains are free of substitution on the carbon chain having a length of at least 5.0.
• the complex structure is significantly larger than each of the molecules of the first type and the third component before they join together. Where the underlying constituent molecules of the first type and the third component are sufficiently large, the complex structure can become so large that, when experiencing exceedingly high shear stress events, such as passing through high-pressure contact points between surfaces typically seen in gear boxes, vulnerable portions in the complex structure can be torn apart.
• the third component can be a base stock, a co-base stock, or an additive component that is normally intended for blending together with the first component in an oil composition.
• the third component is typically not an aliphatic hydrocarbon or mixtures thereof (e.g., PAOs).
• PAO molecules though typically containing two or more long straight carbon chains, tend not to form strong complex structures with each other via van der Waals force between the carbon chains. Without intending to be bound by a particular theory, this is believed to be due to the relatively large molecular sweep volume, and therefore inefficient and relatively weak coupling between the molecules.
• a preferred hydrocarbon type third component comprises an aromatic ring structure, such as benzene, naphthalene, and the like, in its molecular structure.
• Other preferred types of the third component include esters, and other Group V base stocks for lubricant oil compositions.
• a specific type of the third component is an alkylated aromatic base stock typically used in lubricant oils, described below.
• Alkylated aromatic base stocks typically comprise molecules that may be represented by the following formula (F-5):
• circle A represents an aromatic ring structure such as the substituted or unsubstituted ring structure, single or fused, of benzene, biphenyl, triphenyl, naphthalene, anthracene, phenanthrene, benzofuran, and the like
• R s the same or different at each occurrence, independently represents a substituted or unsubstituted hydrocarbyl group (preferably an alkyl group) attached to the aromatic ring structure
• m is a positive integer.
• m For AA base stocks for the purpose of the third component of the oil compositions of the present invention, m > 2.
• Each R s is defined as a side chain group, which would constitute terminal carbon chains that do not share a common atom.
• the total number of carbon atoms in the longest carbon chain with one end attaching to the aromatic ring in each R s is defined as the length of the side chain group or the length of the terminal carbon chain.
• 2-n-dodecyl-7-n-dodecyl-naphthalene (F-6) below) would have an average side chain group length of 12
• l-methyl-7-n-dodecyl-naphthalene (F-4 above)) would have an average side chain group length of 6.5. (F-6).
• the (F-6) molecule would be an example of the third component to be avoided in the oil composition of the present invention because each terminal carbon chain has more than 5 carbon atoms.
• the (F-4) molecule shown above would not be considered as a third component in the oil component of the present invention because one terminal carbon chain has fewer than 5 carbon atoms therein, and it has only one terminal carbon chain having more than 5 carbon atoms therein.
• Exemplary AA base stocks include alkylated naphthalenes base stock ("AN base stock") having a naphthalene ring to which one or more substituted or non-substituted alkyl side chain group(s), the same or different, is attached.
• AN base stock alkylated naphthalenes base stock
• an exemplary AN base stock comprises a mixture of n-C16-alkyl substituted naphthalenes, l-methyl-n-C15-alkyl substituted naphthalenes at the one or more locations on the naphthalene nucleus.
• Such AN base stock is commercially available from ExxonMobil Chemical Company, Houston, Texas, U.S.A., as SynessticTM AN.
• the n-C16-alkyl side chain group is considered to have a side group length (Lsc) of 16, and the l-methyl-C15-alkyl is considered to have an Lsc of 15.
• Lsc side group length
• the average Lsc of the longest 5%, 10%, 20%, 40%, 50%, and 100% of the side chain groups which are referred to as Lsc(5%), Lsc(10%), Lsc(20%), Lsc(40%), Lsc(50%), and Lsc(100%), respectively, are 16, 16, 16, 16, 16, 16. 15.5, respectively.
• the AA base stock molecules for the purpose of the various components relating to the oil compositions of the present invention have an average side chain group length of the longest 5% of the side chain groups of Lsc(5%) in a range from Lsc(5%)l to Lsc(5%)2, where Lsc(5%)l and Lsc(5%)2 can be, independently, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, as long as Lsc(5%)l ⁇ Lsc(5%)2.
• the AA base stock molecules for the purpose of the various components relating to the oil compositions of the present invention have an average side chain group length of the longest 10% of the side chain groups of Lsc(10%) in a range from Lsc(10%)l to Lsc(10%)2, where Lsc(10%)l and Lsc(10%)2 can be, independently, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, as long as Lsc(10%)l ⁇ Lsc(10%)2.
• the AA base stock molecules for the purpose of the various components relating to the oil compositions of the present invention have an average side chain group length of the longest 20% of the side chain groups of Lsc(20%) in a range from Lsc(20%)l to Lsc(20%)2, where Lsc(20%)l and Lsc(20%)2 can be, independently, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, as long as Lsc(20%)l ⁇ Lsc(20%)2.
• the AA base stock molecules for the purpose of the various components relating to the oil compositions of the present invention have an average side chain group length of the longest 40% of the side chain groups of Lsc(40%) in a range from Lsc(40%)l to Lsc(40%)2, where Lsc(40%)l and Lsc(40%)2 can be, independently, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, as long as Lsc(40%)l ⁇ Lsc(40%)2.
• the AA base stock molecules for the purpose of the various components relating to the oil compositions of the present invention have an average side chain group length of the longest 50% of the side chain groups of Lsc(50%) in a range from Lsc(50%)l to Lsc(50%)2, where Lsc(50%)l and Lsc(50%)2 can be, independently, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, as long as Lsc(50%)l ⁇ Lsc(50%)2.
• the AA base stock molecules for the purpose of the various components relating to the oil compositions of the present invention have an average side chain group length of all of the side chain groups of Lsc(100%) in a range from Lsc(100%)l to Lsc(100%)2, where Lsc(100%)l and Lsc(100%)2 can be, independently, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, as long as Lsc(100%)l ⁇ Lsc(100%)2.
• one skilled in the art can determine the Lsc(5%), Lsc(10%), Lsc(20%), Lsc(50%), and Lsc(100%) values of a given AA base stock material by using separation and characterization techniques available to organic chemists.
• separation and characterization techniques available to organic chemists.
• gas chromatography/mass spectroscopy machines equipped with boiling point column separator can be used to separate and identify individual chemical species and fractions; and standard characterization methods such as NMR, IR, and UV spectroscopy can be used to further confirm the structures.
• the alkylated aromatic base stock has a bromine number in the range from Nb(AA)l to Nb(AA)2, where Nb(AA)l and Nb(AA)2 can be, independently, 0, 0.2, 0.4, 0.5, 0.6, 0.8, 1.0, 1.5, 2.0, 2.5, 3.0, as long as Nb(AA)l ⁇ Nb(AA)2.
• the AA base stock for the purpose of the various components relating to the oil compositions of the present invention may be produced by, e.g., alkylating an aromatic compound by an alkylating agent in the presence of an alkylation catalyst.
• alkylbenzene base stocks can be produced by alkylation of benzene or substituted benzene by a LAO, alkyl halides, alcohols, and the like, in the presence of a solid acid such as zeolites.
• alkylated naphthalene bases stocks can be produced by alkylation of naphthalene or substituted benzene by a LAO, alkyl halides, alcohols, and the like, in the presence of a solid acid such as zeolites.
• esters regarded as the third component relating to the oil compositions of the present invention include ester-type base stocks comprising two or more long straight alkyl chains in the molecules thereof.
• Such esters can be, but are not limited to: long-chain carboxylic acid esters of polyalcohols or long-chain alcohol esters of polyacids; phosphates, sulphates, and sulphonates of long-chain alcohols.
• Exemplary esters regarded as the third component are:
• the three long straight terminal alkyl chains in (F-7), when extended and relaxed, can align with the pendant groups of one or more molecules of the first type, described above. When completely relaxed, the three alkyl groups extend in directions that form an angle theta of about 109° relative to each other.
• the two long straight terminal alkyl chains in (F-9), when extended and relaxed, can align with the pendant groups of one or more molecules of the first type as well. When completely relaxed, the two alkyl groups extend in directions that form an angle theta of about 60° relative to each other.
• the two long straight terminal alkyl chains in formula (F-8), when completely relaxed, extend in directions that form an angle theta of about 180° relative to each other.
• the third type of molecules contained in the third component desirably have a number average molecular weight of no more than 2000, preferably no more than 1500, 1,000, 800, 600, or even 500. Small molecules of the third type tend to interact more effectively with two or more molecules of the first type to form large equivalent molecular weight, shearable complex structures.
• Different types of base stocks may be blended to form a formulated lubricant composition to provide desired properties of the lubricant composition.
• the molecules of these different types of base stocks may interact to produce a synergistic effect.
• conventional PAO base stocks when mixed with alkylated naphthalene base stocks, enhanced oxidation stability can be achieved. Such effect is described in, e.g., U.S. Patent No. 5,602,086.
• the oil composition of the present invention comprises a first component such as a PAO base stock, a second component, but is essentially free of a third component, each described in detail above.
• Shear stability of a lubricating oil composition indicates the viscosity change of the oil composition after having been exposed to high shear stress events for a prolonged period of time.
• Lubricating oil compositions used to lubricate surfaces in close contact such as the surfaces of gears in gear boxes, automotive transmissions, differentials, clutch boxes, and the like, may be subjected to repeated high-shear stress events.
• the bond energy of C-C single bond is about 346 kJ-mol "1 . It is known that, small hydrocarbon molecules, or those with a very slim structure (such as a completely linear structure with no pendant groups), can slip through the surface contact during transient high shear stress event before a C-C bond breaks.
• Very large hydrocarbon molecules such as those with large molecular weight of higher than 60,000 and multiple pendant groups leading to large size of the molecules, can be subjected to extraordinarily large shear stress during normal use thereof that is sufficient to break a covalent C-C single bond in the molecule, leading to the formation of smaller molecules, and eventually loss of components with the highest molecular weight, and consequently, reduction of viscosity of the oil composition. Therefore, shear stability of a lubricating oil composition has traditionally been measured in terms of viscosity loss under a controlled measurement condition featuring predetermined high shear stress events under a given temperature for a predetermined duration, such as 20 hours, 100 hours, or 192 hours.
• the oil composition of the present invention is substantially free of the third component which comprises multiple molecules of the third type each comprising two terminal carbon chains that do not share a common carbon atom, where (i) the number average molecular weight of the third component is no greater than 2,000; and (ii) the two terminal carbon chains have chain lengths equal to or greater than 5.0; wherein a single molecule of the third type is capable of adjoining two molecules of the first type via van der Waals force between the pendant groups of the molecules of the first type and the two terminal carbon chains in the single molecule of the third type to form a second complex structure, the second complex structures comprising a heavy fraction thereof having an equivalent molecular weight of at least 45,000.
• the molecules of the second type of the second component of the oil composition of the present invention do contain one or more terminal carbon chains having an average chain length of at least 5.0; and each of the molecules of the first type is capable of adjoining multiple molecules of the second type through the interaction between the multiple pendant groups and the terminal carbon chains of the molecules of the second type via van der Waals force to form a stable first complex structure, the first complex structures comprising a first heavy fraction thereof having an equivalent molecular weight of at least 45,000; and the total maximum theoretical concentration of the first heavy fraction of the first complex structure, based on the total weight of the first component and the second component, is Cl l wt%.
• Cl l ⁇ 10 preferably Cl l ⁇ 8, Cl l ⁇ 6, Cl l ⁇ 5, Cl l ⁇ 4, Cl l ⁇ 3, Cl l ⁇ 2, or Cl l ⁇ 1.
• the total maximum theoretical concentration of the first heavy fraction of the first complex structure can be determined from the molecular weight distributions of the first component and the third component.
• a given value e.g. 45,000
• all molecules of the first type and all molecules of the second type capable of forming such complex structure having such high molecular weight indeed form such structure to the extent either all molecules of the first type or all molecules of the second type available for such formation are consumed.
• the maximum theoretical concentration is a good indicator of the shear stability of the oil comprising a mixture of the first component and the second component.
• the second component is a small molecule base stock material (e.g., with an average number average molecular weight not exceeding 500)
• the total weight of the first heavy fraction of the first complex structure depends partly on the total weight of the heavy fraction in the first component that has molecular weight of at least 22,500.
• the second component is also an oligomeric or polymeric base stock material (e.g., a PAO material differing from the first component)
• the total weight of the first heavy fraction of the first complex structure depends on the total weight of the heavy fraction in the first component and the heavy fraction in the second component.
• the ability of the two chains to attach to two pendant groups of two different molecules of the first type may be affected by the steric hindrance depending on the angle theta.
• the larger the angle theta i.e., the closer it is to 180°
• the smaller the angle theta i.e., the closer it is to 0°
• the angle theta is no more than 45°, the steric hindrance is so severe that one can consider the molecule to be substantially incapable of adjoining two molecules of the first type through interaction with two pendant groups of the two molecules of the first type via van der Waals force.
• the pendant groups especially the longest 5%, 10%, 15%, or 20%, of the side chains or terminal carbon chains of the molecules of the first type and the third type are relatively long, e.g., where they comprise at least 5 carbon atoms (or at least 6, 7, 8, 9, 10, 11 , 12, 13, 14, 15, 16, 17, 18, 19, 20, 21 , 22, 23, 24, 25, 26, 27, 28, 29, or 30 carbon atoms) in the longest carbon chain thereof
• the interaction of the long chains can result in intimate alignment of relatively long chains, resulting in relatively strong total van der Waals force between them.
• the interacting pendant groups, side chains or terminal carbon chains of the molecules of the first type and the third type have comparative lengths, for example, where the ratio of the total number of carbon atoms in the carbon chain in the pendant group, side chain, or terminal carbon chain in a molecule of the first type to that in a molecule of the third type is in the range from rl to r2, where rl and r2 can be, independently, 0.50, 0.60, 0.70, 0.80, 0.90, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, as long as rl ⁇ r2, strong van der Waals link can be formed relatively easily.
• improvement in oxidation stability can be achieved by blending a PAO base stock with an AA base stock, if the pendant group length (Lpg) of pendant groups, especially the longer pendant groups (e.g., the longest 5%, 10%, 20%, 40%, or 50%), attached to the carbon backbone of the PAO molecules are comparable to the side chain group length (Lsc) of the side chain groups, especially the longer side chain groups (e.g., the longest 5%, 10%, 20%, 40%, or 50%), attached to the aromatic ring structure of the AA molecules.
• Lpg pendant group length
• Lsc side chain group length
• the longer side chain groups e.g., the longest 5%, 10%, 20%, 40%, or 50%
• the longest 5% of the pendant groups of all of the molecules of the PAO base stock have an average pendent group length of Lpg(5%); the longest 5% of all of the side chain groups of all of the molecules of the alkylated aromatic base stock have an average side chain group length of Lsc(5%); and
• the longest 10% of the pendant groups of all of the molecules of the PAO base stock have an average pendent group length of Lpg(10%); the longest 10% of all of the side chain groups of all of the molecules of the alkylated aromatic base stock have an average side chain group length of Lsc(10%); and
• Lsc(10%) Preferably Lsc(10
• the longest 20% of the pendant groups of all of the molecules of the PAO base stock have an average pendent group length of Lpg(20%); the longest 20% of all of the side chain groups of all of the molecules of the alkylated aromatic base stock have an average side chain group length of Lsc(20%); and
• Lsc(20%) Preferably Lsc(20)
• the longest 40% of the pendant groups of all of the molecules of the PAO base stock have an average pendent group length of Lpg(40%); the longest 40% of all of the side chain groups of all of the molecules of the alkylated aromatic base stock have an average side chain group length of Lsc(40%); and
• Lsc(40%) Preferably Lsc(40)
• the longest 50% of the pendant groups of all of the molecules of the PAO base stock have an average pendent group length of Lpg(50%); the longest 50% of all of the side chain groups of all of the molecules of the alkylated aromatic base stock have an average side chain group length of Lsc(50%); and
• Lsc(50%) Preferably Lsc(50%)
• the entirety of the pendant groups of all of the molecules of the PAO base stock have an average pendent group length of Lpg(100%); the entirety of all of the side chain groups of all of the molecules of the alkylated aromatic base stock have an average side chain group length of Lsc(100%); and
• Lsc(100%) >
• LAOs linear alpha olefins
• mPAOs metallocene PAOs
• isomerization of the LAOs and oligomers causing mobility of the carbon-carbon double bonds can be avoided or reduced.
• conventional non-metallocene catalyst systems such as Lewis acid-based catalysts (such as Friedel-Crafts catalysts) are used in the polymerization step, appreciable isomerization can occur.
• mPAOs tend to have significantly fewer short pendant groups (methyl, ethyl, C3, C4, and the like) attached to the carbon backbone thereof, in contrast to the large quantities of such short pendant groups on the carbon backbone of conventional PAOs (cPAOs).
• cPAOs conventional PAOs
• mPAOs tend to have significantly longer Lpg(10%), Lpg(20%), Lpg(40%), Lpg(50%), and even Lpg(100%) than cPAOs.
• Lsc(10%) > Lpg(10%)
• Lsc(20%) > Lpg(20%)
• Lsc(40%) > Lpg(40%)
• Lsc(50%) > Lpg(50%)
• Lsc(l 00%) > Lsc(l 00%)
• an mPAO blend would be preferred over a cPAO base stock for the purpose of the present invention.
• a regio-regular structure of the PAO used for the oil composition of the present invention can also facilitate the alignment, interaction and affinity of the pendant groups, the side chain groups, and the terminal carbon chains.
• the weight percentage of the first component (such as a PAO base stock) relative to the total weight of the first component and the second component (such as an AA base stock(s)) in the oil composition can range from: (I) PI wt% to P wt%, where PI and P2 can be, independently, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 92, 94, 95, 96, 98, or 99, as long as PI ⁇ P2; (II) preferably from 25 wt% to 95 wt%; (III) more preferably from 30 wt% to 90 wt%; (IV) still more preferably from 35 wt% to 90 wt%; (V) still more preferably from 40% to 90 wt%; and (VI) most preferably from 50 wt% to 85 wt%.
• PI and P2 can be, independently, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55,
• the mole percentage of the first component (such as a PAO base stock) relative to the total moles of all first component and the second component (such as an AA base stock) in the blend can range from (I) P3 mol% to P4 mol%, where P3 and P4 can be, independently, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 92, 94, 95, 96, 98, or 99, as long as P3 ⁇ P4; (II) preferably from 20 mol% to 90 mol%; (III) more preferably from 25 mol% to 90 mol%; (IV) still more preferably from 30 mol% to 90 mol%; (V) still more preferably from 40 mol% to 90 mol%; and (VI) most preferably from 50 mol% to 80 mol%.
• P3 and P4 can be, independently, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80,
• molar ratio of PAO molecules to AN molecules is in a range from R(l) to R(2), where R(l) and R(2) can be, independently, 1, 1.2, 1.4, 1.5, 1.6, 1.8, 2.0, 2.2, 2.4, 2.5, 2.6, 2.8, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 7.0, 8.0, 9.0, 10.0, as long as R(l) ⁇ R(2).
• the lubricant oil composition can also include any one or more additives as is common in the art.
• the lubricant comprises one or more additives, such as oxidation inhibitors, antioxidants, dispersants, detergents, corrosion inhibitors, rust inhibitors, metal deactivators, anti-wear agents, extreme pressure additives, anti-seizure agents, non-olefin based pour point depressants, wax modifiers, viscosity index improvers, viscosity modifiers, fluid-loss additives, seal compatibility agents, friction modifiers, lubricity agents, anti-staining agents, chromophoric agents, defoamants, demulsifiers, emulsifiers, densifiers, wetting agents, gelling agents, tackiness agents, colorants, and blends thereof.
• additives such as oxidation inhibitors, antioxidants, dispersants, detergents, corrosion inhibitors, rust inhibitors, metal deactivators, anti-wear agents, extreme pressure additives, anti-s
• a lubricant composition incorporating the blend would have improved oxidation stability while maintaining the same quantity of antioxidants added therein. This can reduce the overall cost of the lubricant and negative effect on the overall performance of the lubricant as a result of the use of high concentrations of antioxidants. Alternatively, the life of the lubricant, and hence drain interval thereof, can be extended while maintaining the same quantity of antioxidant included therein.
• the blend may comprise an antioxidant at a concentration in the range from C(ao)l ppm to C(ao)2 ppm, based on the total weight of the PAO base stock and the AA base stock, where C(ao)l and C(ao)2 can be, independently, 0, 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, as long as C(ao)l ⁇ C(ao)2.
• the oil composition of the present invention has an overall bromine number in the range from Nb(bl)l to Nb(bl)2, where Nb(bl)l and Nb(bl)2 can be, independently, 0, 0.2, 0.4, 0.5, 0.6, 0.8, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, as long as NB(bl)K Nb(bl)2.
• oil compositions were made and tested for SS20, SS100, and SS192.
• the oil compositions as specified, comprise one or more of the following:
• a First Base Stock (BS l): an mPAO base stock made from a monomer mixture of 1- octene and 1-dodecene at a weight ratio of 70:30 (molar ratio of about 78:22) in the presence of a metallocene catalyst system, having a typical KV100 of about 300 cSt, a number average molecular weight (Mn) of about 6660, and molecular weight distribution as follows:
• the BS l mPAO base stock comprises macromolecules that are primarily isotactic, and a structure schematically illustrated by (F-3a) above.
• each of the molecules of BS l comprises multiple C8 pendant groups and multiple CIO pendant groups.
• a Second Base Stock (BS2): an NA-type base stock comprising about 90 mol% of n-pentadecylnaphthalene (single-alkyl portion, BSfirst) and about 10 mol% of alpha,beta-di- n-pentadecylnaphthalene (two-alkyl portion (BS2-2), where alpha, beta denotes the two different benzene rings in the naphthalene ring).
• BS2-2 is considered as a candidate for the third component of the oil composition of the present invention given that the two long, linear C15 alkyl can interact with pendant groups of multiple molecules of the first type (such as BS1 above) of the oil composition;
• BSfirst is considered as a candidate for the second component of the oil composition of the present invention given that the single, linear C15 alkyl can interact with a pendant group of a single molecule of the first component (such as BS1 above) of the oil composition.
• a Third Base Stock (BS3): an ester base stock represented by formula (F-8) above.
• Each molecule of BS3 comprises two C8 terminal carbon chains that extend in directions that form an angle theta of 180°, enabling it to link to pendant groups of two molecules of the first type of the oil composition (such as BS 1 above) via sufficiently strong van der Waals force to form a relatively stable and strong second complex structure, functioning as a potent third component of the oil composition of the present invention.
• a Fourth Base Stock an ester base stock comprising molecules having structure that can be approximately represented by formula (F-7) above.
• Each molecule of BS4 comprises three CIO terminal carbon chains that extend in directions that form an angle theta of about 109° between any two of them. Theoretically, each of the CIO terminal carbon chain is capable of linking with a pendant group of two a molecule of the first type of the first component of the oil composition (such as BS1 above) via van der Waals force.
• molecules of BS4 may function as a third component of the oil composition of the present invention, but its efficacy is multiplied by a factor of tan(theta/4), which is about 0.52.
• a Fifth Base Stock (BS5) an ester base stock represented by formula (F-9) above.
• Each molecule of BS5 comprises two C8 terminal carbon chains that extend in directions that form an angle theta of about 60°.
• each of the C8 terminal carbon chain is capable of linking with a pendant group of a molecule of the first type of the first component of the oil composition (such as BS1 above) via van der Waals force.
• a pendant group of a molecule of the first type of the first component of the oil composition such as BS1 above
• van der Waals force steric hindrance of any two molecules of the first type (such as BS 1 above), especially when they are large, connected to two of C8 terminal carbon chains can be significant enough to reduce the stability of such second complex structure. Therefore, molecules of BS4 may function as a third component of the oil composition, but its efficacy is multiplied by a factor of tan(theta/4), which is about 0.27.
• a Sixth Base Stock (BS6): a non-metallocene PAO base stock available from ExxonMobil Chemical Company, Houston, Texas, U.S.A., having a typical KV100 of about 6 cSt and a number average molecular weight of no more than 800; the BS6 PAO molecules typically comprise two long terminal carbon chain at the end of the carbon backbone, and multiple short-chain pendant groups such as methyl, ethyl, propyl, and the like, attached to the carbon backbone thereof; long, pendant groups having five or more carbon atoms may be present on their molecules as well.
• BS6 a non-metallocene PAO base stock available from ExxonMobil Chemical Company, Houston, Texas, U.S.A., having a typical KV100 of about 6 cSt and a number average molecular weight of no more than 800; the BS6 PAO molecules typically comprise two long terminal carbon chain at the end of the carbon backbone, and multiple short-chain pendant groups such as methyl
• AdPak additive packages
• Additive packages are typically added to formulated lubricant oil compositions in addition to base stocks, for multiple purposes such as enhanced performances in oxidation resistance, wear resistance, foaming, and the like.
• the Adpak for different oil compositions may be very different.
• the following lubricating oil compositions were formulated and tested for various properties, especially shear stability (SS20, SS100, and SS192). These oil compositions correspond to AGO 90 grade. The same typical Adpak- 1 for this grade was used in these examples at the same treat rate (concentration in weight percents). BS1 was used at appropriately the same treat rates in all these compositions. In Examples A2, A3, A4, and A5, four different co-base stocks, BS2, BS3, BS4, and BS5, were included at the same treat rate of about 20 wt%, and a same co-base stock, BS6, was included essentially as a low- viscosity diluent at very close treat rates.
• Example Al only BS6 was used as the co-base stock. These examples showed differing SSI 92 of the compositions, which are due to the interaction between the molecules of BS1 (especially the large molecular-weight fraction, such as those having molecular weight of at least 22,500) and the molecules of BS2, BS3, BS4, and BS5.
• BS2 comprises about 90% by mole of molecules having a single long terminal carbon chain (side chain connected to a naphthalene nucleus), which are substantially incapable of joining two BSl molecules through interaction with long pendant groups via van der Waals force. BS2 further comprises about 10% by mole of molecules having two long terminal carbon chains that are spread at an angle theta of about 180°.
• Example A3 Similar to BS3 molecules, these two-arm BS2 molecules have strong ability to join two BS l molecules to form stable complex structures. However, because of the significantly smaller concentration of such two-arm molecules than in Example A3, the oil of Example A2 demonstrated much smaller SS 192 than Example A3.
• Example A4 comprises three terminal carbon chains spread at an angle theta of about 109° relative to each other in the space. While theoretically it is possible that all three may interact with the long, pendant groups in BSl to form shearable complex structures, because of the closeness of these three long arms, once one of them aligns with a long pendant group of one BSl molecule, the possibility of a second long arm aligning with a second pendant group of the same or different BSl molecule is very significantly reduced. Therefore, the oil composition of Example A4 demonstrated a SS192 similar but smaller than that of Example A2, and much smaller than that of Example A3.
• Example A5 comprises two terminal carbon chains spread at an angle theta of about 60° relative to each other (considering the rotational possibility of the O-C linkage in the ester linkages). While theoretically it is possible that both may interact with the long, pendant groups in BS l to form shearable complex structures, because of the closeness of the two long terminal carbon chains, once one of them aligns with a long pendant group of one BS l molecule, the possibility of a second long terminal carbon chain aligning with a second pendant group of the same or different BSl molecule is very significantly reduced due to significant steric hindrance. Therefore, the oil composition of Example A5 demonstrated a SSI 92 lower than that of Examples A2, A3, and A4.
• Example Al because no additional base stock materials having two arms capable of attaching to two BSl molecules are included, other than BS6 and BS l per se, the oil composition demonstrated the lowest SSI 92 among all Examples Al, A2, A3, A4, and A5.
• Example Al also shows that the interaction between and among the molecules of SBl and molecules of SB7 are negligible compared to the molecules of SBl and molecules of BS2, BS3, BS4, and BS5 with respect to contribution to SS192. Because SB7 and BS2, BS3, BS4, and BS5 are all fairly stable, small molecules per se, it is believed that their interaction will not result in complex structures sufficiently large and stable to result in significant shear breakage under the testing conditions.
• oil formulations B1-A5 were formed from the same base stocks and tested for properties including SSI 92. These oil compositions correspond to industrial grease oil IGO VG100 grade. A differing additive package (Adpak- 2) for this grade was used. Composition and properties Data are included in TABLE II.
• Example B3 comprising BS3 as the co-base stock demonstrated the highest SS192
• Example B5 comprising BS5 demonstrated the lowest SS 192
• Examples B2 and B5 demonstrated similar SS 192 between Examples B3 and B5.
• Example Bl showed significantly higher SSI 92 compared to Example Al, showing that the Adpak-2 resulted in significant SS 192 in Example Bl where no co-base stock other than BS l and BS6 are present.
• the effective of Adpak-2 became largely invisible, because the interaction between the large molecules of SB1 and the molecules of BS2, BS3, BS4, and BS5 dominates.
• the SS192 remains substantially stable from 5 wt% to 10 wt%, and then to 15 wt%. This is because the total amount of shearable, large complex structures between large BSl molecules and the BS5 molecules remains substantially constant given the locations of the two-arms on the BS5 molecules - only a small portion of the BS l molecules are cross-linked before 15 wt%.

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