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
  • C10M133/00—Lubricating compositions characterised by the additive being an organic non-macromolecular compound containing nitrogen
  • C10M133/02—Lubricating compositions characterised by the additive being an organic non-macromolecular compound containing nitrogen having a carbon chain of less than 30 atoms
  • C10M133/38—Heterocyclic nitrogen compounds
  • C10M133/40—Six-membered ring containing nitrogen and carbon only
• • 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
  • C10M2207/281—Esters of (cyclo)aliphatic monocarboxylic acids
• • 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
  • C10M2215/00—Organic non-macromolecular compounds containing nitrogen as ingredients in lubricant compositions
  • C10M2215/22—Heterocyclic nitrogen compounds
  • C10M2215/221—Six-membered rings containing nitrogen and carbon only
• • 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
  • C10N2030/10—Inhibition of oxidation, e.g. anti-oxidants
• • 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
  • C10N2030/32—Light or X-ray resistance
• • 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
  • C10N2030/78—Fuel contamination
• • 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
  • C10N2040/25—Internal-combustion engines
  • C10N2040/252—Diesel engines

Definitions

• the present invention relates to a lubricating oil composition for particular use in the crankcase of a diesel (compression-ignited) internal combustion engine, wherein the internal combustion engine is fuelled at least in part with a biodiesel fuel, and to the improvement in resistance to oxidation of such lubricating oil compositions.
• FAAEs fatty acid alkyl esters
• FAMEs fatty acid methyl esters
• FAME fatty acid methyl esters
• FAME can be produced from various oil-derived feedstocks such as soybean, rapeseed, sunflower seed, coconut and used vegetable oils.
• FAAEs may be added for a variety of reasons, including to reduce the environmental impact of the fuel production and consumption process or to improve lubricity.
• the lubricant oil compositions used for lubricating an internal combustion engine can often become diluted with the biofuel which is used to fuel the engine.
• Biodiesel fuels include components of low volatility which are slow to vaporize after injection of the fuel into the engine.
• an unburnt portion of the biodiesel and some of the resulting partially combusted decomposition products become mixed with the lubricating oil composition on the cylinder wall and are washed down into the oil sump, thereby contaminating the crankcase lubricant.
• the biodiesel fuel in the contaminated lubricant may form further decomposition products due to the extreme conditions during lubrication of the engine.
• dilution of a lubricating oil composition with a FAAE can lead to an undesirable effect on a lubricating oil composition's ability to control oxidative stability.
• a FAAE such as a FAME
• the presence of olefinic double bonds and ester functionality in the biodiesel results in the biodiesel fuels being susceptible to oxidative degradation, and renders the lubricating oil composition oxidatively unstable and more susceptible to sludge and deposit formation.
• the higher the biodiesel contamination in the oil the lower the oxidative stability of the lubricating oil composition.
• a lubricating oil composition for use in the crankcase of an internal combustion engine which reduces the loss in oxidative stability which occurs when the internal combustion engine is fuelled with a biofuel such as a biodiesel.
• Hindered amines are chemical compounds containing an amine functional group surrounded by a crowded steric environment. They have uses such as gas scrubbing, as stabilizers against light-induced polymer degradation, and as reagents for organic synthesis. Hindered amine light stabilizers are typically derivatives of 2,2,6,6-tetramethyl piperidine and are extremely efficient stabilizers against light-induced degradation of most polymers.
• US2007/0151143 discloses stabilized biodiesel fuel compositions, which compositions comprise a biodiesel fuel, for example the methyl esters of the fatty acids of rapeseed or soy oil, and one or more additives selected from the group consisting of the 3-arylbenzofuranones and the hindered amine light stabilizers, and optionally, one or more hindered phenolic antioxidants.
• a biodiesel fuel for example the methyl esters of the fatty acids of rapeseed or soy oil
• additives selected from the group consisting of the 3-arylbenzofuranones and the hindered amine light stabilizers, and optionally, one or more hindered phenolic antioxidants.
• lubricating oil compositions comprising hindered amine light stabilizers.
• hindered amine light stabilizers can be used to reduce the loss in oxidative stability of a lubricating oil composition for the crankcase of an internal combustion engine, wherein the internal combustion engine is fuelled with a biofuel composition, in particular a biofuel composition which comprises a fatty acid alkyl ester.
• a lubricating oil composition for the crankcase of an internal combustion engine comprising (a) base oil; (b) hindered amine light stabilizer; and (c) an additional performance additive.
• the present invention is especially useful for the case wherein the lubricating oil composition is contaminated with at least 0.3 weight%, based on the total weight of the lubricating oil composition, of a biofuel or a decomposition product thereof, or mixtures thereof.
• a hindered amine light stabilizer for reducing the loss in oxidative stability of a lubricating composition for the crankcase of an internal combustion engine, when the internal combustion engine is fuelled with a biofuel composition, preferably wherein the biofuel composition comprises a fatty acid alkyl ester.
• a hindered amine light stabilizer for improving the oxidative stability of a lubricating oil composition for the crankcase of an internal combustion engine, when the internal combustion engine is fuelled with a biofuel composition, preferably wherein the biofuel composition comprises a fatty acid alkyl ester.
• a method for improving the resistance to oxidation of lubricating oil compositions used to lubricate engines fuelled with biofuels comprising adding to the lubricating oil composition an additive amount of one or more hindered amine light stabilizers.
• biofuel means a fuel derived at least in part from a renewable biological resource, preferably biodiesel fuel.
• a diesel fuel composition used to fuel a compression ignition engine may incorporate a fatty acid alkyl ester (FAAE) such as a fatty acid methyl ester (FAME) as a fuel component.
• FAAE fatty acid alkyl ester
• FAME fatty acid methyl ester
• the present invention is especially useful for the case wherein the lubricating oil composition is contaminated with at least 0.3 weight%, based on the total weight of the lubricating oil composition, of a biofuel or a decomposition product thereof, or mixtures thereof.
• reducing the loss in oxidative stability means reducing the loss in oxidative stability which is experienced when a lubricating oil composition is diluted with a biofuel, e.g. fatty acid alkyl ester (FAAE) such as a FAME.
• a biofuel e.g. fatty acid alkyl ester (FAAE) such as a FAME.
• the term "improving oxidative stability” means increasing the onset time to oxidation of a lubricating oil composition which has been diluted with a biofuel, e.g. fatty acid alkyl ester (FAAE) such as a FAME, as measured by ASTM D6186 which is a standard test method for measuring oxidation induction time of a lubricating oil composition by Pressure Differential Scanning Calorimetry (pDSC).
• FAAE fatty acid alkyl ester
• ASTM D6186 is a standard test method for measuring oxidation induction time of a lubricating oil composition by Pressure Differential Scanning Calorimetry (pDSC).
• the % improvement in oxidative stability provided by the lubricating oil compositions of the present invention is at least a 20% improvement in oxidative stability, more preferably at least a 30% improvement in oxidative stability, even more preferably at least a 50% improvement, especially at least a 60% improvement in oxidative stability, compared to the oxidative stability of an equivalent lubricating oil composition which has been diluted with FAME but which does not contain a hindered amine light stabiliser.
• the term "improving the resistance to oxidation” means (i) reducing the loss in oxidative stability which is experienced when a lubricating oil composition is diluted with a biofuel, and/or (ii) improving the oxidative stability of a FAME-diluted lubricating composition beyond that of an equivalent FAME-diluted lubricating composition which does not contain a hindered amine light stabiliser.
• the oxidative stability of the lubricating oil composition is measured according to ASTM D6186 which is a standard test method for measuring oxidation induction time of a lubricating oil composition by Pressure Differential Scanning Calorimetry (pDSC).
• the FAAE will typically be added to the fuel composition as a blend (i.e. a physical mixture), conveniently before the composition is introduced into an internal combustion engine or other system which is to be run on the composition.
• Other fuel components and/or fuel additives may also be incorporated into the composition, either before or after addition of the FAAE and either before or during use of the composition in a combustion system.
• the volume fractions v and v' must each have a value between 0 and 1.
• the actual volume fraction of FAAE, v is preferably at least 0.02 lower than the "linear" volume fraction v', more preferably at least 0.05 or 0.08 or 0.1 lower, most preferably at least 0.2, 0.3 or 0.5 lower and in cases up to 0.6 or 0.8 lower than v'.
• the actual volume fraction v is preferably 0.25 or less, more preferably 0.2 or less, yet more preferably 0.15 or 0.1 or 0.07 or less. It may for example be from 0.01 to 0.25, preferably from 0.05 to 0.25, more preferably from 0.05 or 0.1 to 0.2.
• the concentration of the FAAE in the overall fuel composition is preferably 25% v/v or less, more preferably 20% v/v or less, yet more preferably 15 or 10 or 7% v/v or less. As a minimum it may be 0.05% v/v or greater, preferably 1% v/v or greater, more preferably 2% or 5% v/v or greater, most preferably 7 or 10% v/v or greater.
• Fatty acid alkyl esters of which the most commonly used in the present context are the methyl esters, are already known as renewable diesel fuels (so-called “biodiesel” fuels). They contain long chain carboxylic acid molecules (generally from 10 to 22 carbon atoms long), each having an alcohol molecule attached to one end.
• Organically derived oils such as vegetable oils (including recycled vegetable oils) and animal fats can be subjected to a transesterification process with an alcohol (typically a C 1 to C 5 alcohol) to form the corresponding fatty esters, typically mono-alkylated.
• This process which is suitably either acid- or base-catalysed, such as with the base KOH, converts the triglycerides contained in the oils into fatty acid esters and free glycerol, by separating the fatty acid components of the oils from their glycerol backbone.
• the FAAE may be any alkylated fatty acid or mixture of fatty acids. Its fatty acid component(s) are preferably derived from a biological source, more preferably a vegetable source. They may be saturated or unsaturated; if the latter, they may have one or more double bonds. They may be branched or un-branched. Suitably they will have from 10 to 30, more suitably from 10 to 22 or from 12 to 22, carbon atoms in addition to the acid group(s) -CO 2 H. A FAAE will typically comprise a mixture of different fatty acid esters of different chain lengths, depending on its source.
• the commonly available rapeseed oil contains mixtures of palmitic acid (C 16 ), stearic acid (C 18 ), oleic, linoleic and linolenic acids (C 18 , with one, two and three unsaturated carbon-carbon bonds respectively) and sometimes also erucic acid (C 22 ) - of these the oleic and linoleic acids form the major proportion.
• Soybean oil contains a mixture of palmitic, stearic, oleic, linoleic and linolenic acids. Palm oil usually contains a mixture of palmitic, stearic and linoleic acid components.
• the FAAE used in the present invention is preferably derived from a natural fatty oil, for instance a vegetable oil such as rapeseed oil, soybean oil, coconut oil, sunflower oil, palm oil, peanut oil, linseed oil, camelina oil, safflower oil, babassu oil, tallow oil or rice bran oil. It may in particular be an alkyl ester (suitably the methyl ester) of rapeseed, soy, coconut or palm oil.
• the FAAE is preferably a C 1 to C 5 alkyl ester, more preferably a methyl, ethyl or propyl (suitably isopropyl) ester, yet more preferably a methyl or ethyl ester and in particular a methyl ester.
• RME rapeseed methyl ester
• SME soy methyl ester
• POME palm oil methyl ester
• CME coconut methyl ester
• the refined product is based on the crude but with some of the higher and lower alkyl chains (typically the C 6 , C 8 , C 10 , C 16 and C 18 ) components removed) and mixtures thereof.
• it may be either natural or synthetic, refined or unrefined ("crude").
• the FAAE suitably complies with specifications applying to the rest of the fuel composition, and/or to the base fuel to which it is added, bearing in mind the intended use to which the composition is to be put (for example, in which geographical area and at what time of year).
• the FAAE preferably has a flash point (IP 34) of greater than 101°C; a kinematic viscosity at 40°C (IP 71) of 1.9 to 6.0 centistokes, preferably 3.5 to 5.0 centistokes; a density from 845 to 910 kg/m 3 , preferably from 860 to 900 kg/m 3 , at 15°C (IP 365, EN ISO 12185 or EN ISO 3675); a water content (IP 386) of less than 500 ppm; a T95 (the temperature at which 95% of the fuel has evaporated, measured according to IP 123) of less than 360°C; an acid number (IP 139) of less than 0.8 mgKOH/g, preferably less than 0.5 mgKOH/g; and an
• It also preferably contains (eg, by NMR) less than 0.2% w/w of free methanol, less than 0.02% w/w of free glycerol and greater than 96.5% w/w esters.
• the FAAE may be preferred for the FAAE to conform to the European specification EN 14214 for fatty acid methyl esters for use as diesel fuels.
• the measured cetane number of the FAAE (ASTM D613) is suitably 55 or greater, preferably 58 or 60 or 65 or even 70 or greater.
• Two or more FAAEs may be added to the base fuel, either separately or as a pre-prepared blend, so long as their combined effect is to increase the cetane number of the resultant composition to reach the target number X.
• the total amount x' of the two or more FAAEs must be less than the amount of that same combination of FAAEs which would need to be added to the base fuel in order to achieve the target cetane number X if linear blending rules applied for both or all of the FAAEs.
• the FAAE preferably comprises (i.e. either is or includes) RME or SME.
• the FAAE may be added to the fuel composition for one or more other purposes in addition to the desire to increase cetane number, for instance to reduce life cycle greenhouse gas emissions, to improve lubricity and/or to reduce costs.
• the lubricating oil composition herein typically comprises a base oil and one or more performance additives, in addition to one or more hindered amine light stabilisers.
• base oil used in the lubricating oil compositions herein there are no particular limitations regarding the base oil used in the lubricating oil compositions herein, and various conventional mineral oils, synthetic oils as well as naturally derived esters such as vegetable oils may be conveniently used.
• the base oil used in the present invention may conveniently comprise mixtures of one or more mineral oils and/or one or more synthetic oils; thus, the term "base oil” herein may refer to a blend containing more than one base oil.
• Suitable base oils for use in the lubricating oil composition of the present invention are Group I-III mineral base oils (preferably Group III), Group IV poly-alpha olefins (PAOs), Group II-III Fischer-Tropsch derived base oils (preferably Group III), Group V base oils, and mixtures thereof.
• Group I lubricating oil base oils according to the definitions of American Petroleum Institute (API) for categories I, II, III, IV and V. These API categories are defined in API Publication 1509, 15th Edition, Appendix E, April 2002.
• API American Petroleum Institute
• Mineral oils include liquid petroleum oils and solvent-treated or acid-treated mineral lubricating oil of the paraffinic, naphthenic, or mixed paraffinic/naphthenic type which may be further refined by hydrofinishing processes and/or dewaxing.
• a preferred base oil for use in the lubricating oil compositions herein is a Fischer-Tropsch derived base oil.
• Fischer-Tropsch derived base oils are known in the art.
• Fischer-Tropsch derived is meant that a base oil is, or is derived from, a synthesis product of a Fischer-Tropsch process.
• a Fischer-Tropsch derived base oil may also be referred to as a GTL (Gas-To-Liquids) base oil.
• Suitable Fischer-Tropsch derived base oils that may be conveniently used as the base oil in the lubricating oil composition of the present invention are those as for example disclosed in EP 0 776 959 , EP 0 668 342 , WO 97/21788 , WO 00/15736 , WO 00/14188 , WO 00/14187 , WO 00/14183 , WO 00/14179 , WO 00/08115 , WO 99/41332 , EP 1 029 029 , WO 01/18156 and WO 01/57166 .
• the aromatics content of a Fischer-Tropsch derived base oil will typically be below 1 wt.%, preferably below 0.5 wt.% and more preferably below 0.1 wt.%.
• the base oil has a total paraffin content of at least 80 wt.%, preferably at least 85, more preferably at least 90, yet more preferably at least 95 and most preferably at least 99 wt.%. It suitably has a saturates content (as measured by IP-368) of greater than 98 wt.%.
• the saturates content of the base oil is greater than 99 wt.%, more preferably greater than 99.5 wt.%.
• the base oil preferably also has a content of naphthenic compounds of from 0 to less than 20 wt.%, more preferably of from 0.5 to 10 wt.%.
• the Fischer-Tropsch derived base oil or base oil blend has a kinematic viscosity at 100°C (as measured by ASTM D 7042) in the range of from 1 to 30 mm 2 /s (cSt), preferably from 1 to 25 mm 2 /s (cSt), and more preferably from 2 mm 2 /s to 12 mm 2 /s.
• the Fischer-Tropsch derived base oil has a kinematic viscosity at 100°C (as measured by ASTM D 7042) of at least 2.5 mm 2 /s, more preferably at least 3.0 mm 2 /s.
• the Fischer-Tropsch derived base oil has a kinematic viscosity at 100°C of at most 5.0 mm 2 /s, preferably at most 4.5 mm 2 /s, more preferably at most 4.2 mm 2 /s (e.g. "GTL 4").
• the Fischer-Tropsch derived base oil has a kinematic viscosity at 100°C of at most 8.5 mm 2 /s, preferably at most 8 mm 2 /s (e.g. "GTL 8").
• the Fischer-Tropsch derived base oil when present in the lubricating oil composition herein typically has a kinematic viscosity at 40°C (as measured by ASTM D 7042) of from 10 to 100 mm 2 /s (cSt), preferably from 15 to 50 mm 2 /s.
• a preferred Fischer-Tropsch derived base oil for use herein has a pour point (as measured according to ASTM D 5950) of below -30°C, more preferably below -40°C, and most preferably below -45°C.
• the flash point (as measured by ASTM D92) of the Fischer-Tropsch derived base oil is preferably greater than 120°C, more preferably even greater than 140°C.
• a preferred Fischer-Tropsch derived base oil for use herein has a viscosity index (according to ASTM D 2270) in the range of from 100 to 200.
• the Fischer-Tropsch derived base oil has a viscosity index of at least 125, preferably 130. Also it is preferred that the viscosity index is below 180, preferably below 150.
• Fischer-Tropsch derived base oil contains a blend of two or more Fischer-Tropsch derived base oils
• the above values apply to the blend of the two or more Fischer-Tropsch derived base oils.
• the lubricating oil composition herein preferably comprises 80 wt% or greater of Fischer-Tropsch derived base oil.
• Synthetic oils include hydrocarbon oils such as olefin oligomers (including polyalphaolefin base oils; PAOs), dibasic acid esters, polyol esters, polyalkylene glycols (PAGs), alkyl naphthalenes and dewaxed waxy isomerates.
• hydrocarbon oils such as olefin oligomers (including polyalphaolefin base oils; PAOs), dibasic acid esters, polyol esters, polyalkylene glycols (PAGs), alkyl naphthalenes and dewaxed waxy isomerates.
• Synthetic hydrocarbon base oils sold by the Shell Group under the designation "Shell XHVI" (trade mark) may be conveniently used.
• Poly-alpha olefin base oils PAOs
• Preferred poly-alpha olefin base oils that may be used in the lubricating oil compositions of the present invention may be derived from linear C 2 to C 32 , preferably C 6 to C 16 , alpha olefins.
• Particularly preferred feedstocks for said poly-alpha olefins are 1-octene, 1-decene, 1-dodecene and 1-tetradecene.
• the base oil contains more than 50 wt.%, preferably more than 60 wt.%, more preferably more than 70 wt.%, even more preferably more than 80 wt.%. most preferably more than 90 wt.% Fischer-Tropsch derived base oil.
• not more than 5 wt.%, preferably not more than 2 wt.%, of the base oil is not a Fischer-Tropsch derived base oil. It is even more preferred that 100 wt% of the base oil is based on one or more Fischer-Tropsch derived base oils.
• the total amount of base oil incorporated in the lubricating oil composition of the present invention is preferably in the range of from 60 to 99 wt.%, more preferably in the range of from 65 to 90 wt.% and most preferably in the range of from 70 to 85 wt.%, with respect to the total weight of the lubricating oil composition.
• the base oil (or base oil blend) as used according to the present invention has a kinematic viscosity at 100°C (according to ASTM D445) of above 2.5 cSt and up to 8 cSt.
• the base oil has a kinematic viscosity at 100°C (according to ASTM D445) of between 3.5 and 8 cSt.
• the base oil contains a blend of two or more base oils, it is preferred that the blend has a kinematic viscosity at 100°C of between 3.5 and 7.5 cSt.
• the lubricating composition herein preferably has a Noack volatility (according to ASTM D 5800) of below 15 wt.%.
• the Noack volatility (according to ASTM D 5800) of the composition is between 1 and 15 wt.%, preferably below 14.6 wt.% and more preferably below 14.0 wt.%.
• the lubricating oil composition herein comprises one or more hindered amine light stabilisers, preferably in an amount of from 0.01 wt% to 10 wt%, more preferably in an amount of from 0.25 wt% to 7 wt%, and even more preferably in an amount of from 0.1 wt% to 4 wt%, and especially in an amount of from 0.1 wt% to 2 wt%, by weight of the total lubricating oil composition.
• the hindered amine light stabiliser is a 2,2,6,6-tetraalkyl piperidine derivative which contains at least one moiety of formula: wherein R 1 , R 2 , R 3 , R 4 and R 5 are independently selected from C 1 -C 8 alkyl or R 1 and R 2 or R 3 and R 4 together are pentamethylene.
• Hindered amine light stabilisers are disclosed for example in US patent nos. 5004770 , 5204473 , 5096950 , 5300544 , 5112890 , 5124378 , 5145893 , 5216156 , 5844026 , 5980783 , 6046304 , 6117995 , 6271377 , 6297299 , 6392041 , 6376584 and 6472456 and US application Ser. Nos. 09/714717 and 10/485377 , and US patent application US2007/0151143 . The relevant disclosures of these patents and applications are incorporated herein by reference.
• Suitable hindered amine light stabilizers include, for example, 1-cyclohexyloxy-2,2,6,6-tetramethyl-4-octadecylaminopiperidine; bis(2,2,6,6-tetramethylpiperidin-4-yl) sebacate; bis(1-acetoxy-2,2,6,6-tetramethylpiperidin-4-yl) sebacate; bis(1,2,2,6,6-pentamethyl-4-yl) sebacate; bis(1-cyclohexyloxy-2,2,6,6-tetramethylpiperidin-4-yl) sebacate; bis(1-octyloxy-2,2,6,6-tetramethylpiperidin-4-yl) sebacate; bis(1-acyl-2,2,6,6-tetramethylpiperidin-4-yl) sebacate; bis(1,2,2,6,6-pentamethyl-4-piperidyl) n-butyl-3,5-di-tert-butyl-4
• N-H sterically hindered N-H, N-methyl, N-methoxy, N-propoxy, N-octyloxy, N-cyclohexyloxy, N-acyloxy and N-(2-hydroxy-2-methylpropoxy) analogues of any of the above mentioned compounds.
• N-H hindered amine replacing an N-H hindered amine with an N-methyl hindered amine would be employing the N-methyl analogue in place of the N-H.
• Preferred hindered amine light stabilizers for use herein are selected from bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, and pentamethyl piperidine, and mixtures thereof.
• the lubricating oil composition herein further comprises one or more performance additives, in addition to the hindered amine light stabiliser, such as anti-oxidants, anti-wear additives, dispersants, detergents, overbased detergents, extreme pressure additives, friction modifiers, viscosity index improvers, pour point depressants, metal passivators, corrosion inhibitors, demulsifiers, anti-foam agents, seal compatibility agents and additive diluent base oils, etc.
• performance additives in addition to the hindered amine light stabiliser, such as anti-oxidants, anti-wear additives, dispersants, detergents, overbased detergents, extreme pressure additives, friction modifiers, viscosity index improvers, pour point depressants, metal passivators, corrosion inhibitors, demulsifiers, anti-foam agents, seal compatibility agents and additive diluent base oils, etc.
• Conventional anti-oxidants that may be conveniently used in the lubricating oil compositions of the present invention, in addition to the hindered amine light stabilisers, include diphenylamines (such as "IRGANOX L-57" available from Ciba Specialty Chemicals) as e.g. disclosed in WO 2007/045629 and EP 1 058 720 B1 , phenolic anti-oxidants, etc.
• diphenylamines such as "IRGANOX L-57" available from Ciba Specialty Chemicals
• IRGANOX L-57 available from Ciba Specialty Chemicals
• Anti-wear additives that may be conveniently used include zinc-containing compounds such as zinc dithiophosphate compounds selected from zinc dialkyl-, diaryl- and/or alkylaryl- dithiophosphates, molybdenum-containing compounds, boron-containing compounds and ashless anti-wear additives such as substituted or unsubstituted thiophosphoric acids, and salts thereof.
• zinc-containing compounds such as zinc dithiophosphate compounds selected from zinc dialkyl-, diaryl- and/or alkylaryl- dithiophosphates, molybdenum-containing compounds, boron-containing compounds and ashless anti-wear additives such as substituted or unsubstituted thiophosphoric acids, and salts thereof.
• molybdenum-containing compounds may conveniently include molybdenum dithiocarbamates, trinuclear molybdenum compounds, for example as described in WO 98/26030 , sulphides of molybdenum and molybdenum dithiophosphate.
• Boron-containing compounds that may be conveniently used include borate esters, borated fatty amines, borated epoxides, alkali metal (or mixed alkali metal or alkaline earth metal) borates and borated overbased metal salts.
• the dispersant used is preferably an ashless dispersant. Suitable examples of ashless dispersants are polybutylene succinimide polyamines and Mannich base type dispersants.
• the detergent used is preferably an overbased detergent or detergent mixture containing e.g. salicylate, sulphonate and/or phenate-type detergents.
• viscosity index improvers which may conveniently be used in the lubricating oil composition of the present invention include the styrene-butadiene stellate copolymers, styrene-isoprene stellate copolymers and the polymethacrylate copolymer and ethylene-propylene copolymers (also known as olefin copolymers) of the crystalline and non-crystalline type.
• Dispersant-viscosity index improvers may be used in the lubricating oil composition of the present invention.
• the composition according to the present invention contains less than 1.0 wt.%, preferably less than 0.5 wt.%, of a Viscosity Index improver concentrate (i.e. VI improver plus "carrier oil” or “diluent”), based on the total weight of the composition.
• a Viscosity Index improver concentrate i.e. VI improver plus "carrier oil” or “diluent
• the composition is free of Viscosity Index improver concentrate.
• Viscosity Modifier as used hereafter (such as in Table 2) is meant to be the same as the above-mentioned term "Viscosity Index improver concentrate”.
• the composition contains at least 0.1 wt.% of a pour point depressant.
• a pour point depressant alkylated naphthalene and phenolic polymers, polymethacrylates, maleate/fumarate copolymer esters may be conveniently used as effective pour point depressants.
• compounds such as alkenyl succinic acid or ester moieties thereof, benzotriazole-based compounds and thiodiazole-based compounds may be conveniently used in the lubricating oil composition herein as corrosion inhibitors.
• seal fix or seal compatibility agents include, for example, commercially available aromatic esters.
• the lubricating oil compositions herein may be conveniently prepared by admixing the hindered amine light stabiliser(s) with the base oil(s), and one or more additional performance additives.
• the above-mentioned performance additives are typically present in an amount in the range of from 0.01 to 35.0 wt.%, based on the total weight of the lubricating oil composition, preferably in an amount in the range of from 0.05 to 25.0 wt.%, more preferably from 1.0 to 20.0 wt.%, based on the total weight of the lubricating oil composition.
• the composition contains at least 8.0 wt.%, preferably at least 10.0 wt.%, more preferably at least 11.0 wt% of an additive package comprising an anti-wear additive, a metal detergent, an ashless dispersant, an anti-oxidant, a friction modifier and an anti-foaming agent.
• an additive package comprising an anti-wear additive, a metal detergent, an ashless dispersant, an anti-oxidant, a friction modifier and an anti-foaming agent.
• PCMO Passenger Car Motor Oil
• Comparative Example 1 (Oil A) was a commercially available 5W-30 heavy duty diesel engine oil having a HTHS (High Temperature High Shear) at 150°C (as measured by ASTM D5481) of 3.5 and containing 16 wt% of additives (which includes salicylate detergent, dispersant, zinc-based anti-wear agent, a mixture of aminic and phenolic antioxidants and a corrosion inhibitor), up to 10 wt% of a polymeric viscosity modifier and the remainder a blend of Group III base oils.
• additives which includes salicylate detergent, dispersant, zinc-based anti-wear agent, a mixture of aminic and phenolic antioxidants and a corrosion inhibitor
• Comparative Example 2 (Oil B) was a blend of 90 wt% Oil A and 10 wt% FAME.
• Examples 1 and 2 were blends of Oil B with, respectively, 0.1 wt% and 0.5 wt%, of bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate (abbreviated in Table 1 to "Bis-1").
• Examples 3 and 4 were blends of Oil B with, respectively, 0.1 wt% and 0.5 wt%, of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate (abbreviated in Table 1 to "Bis-2").
• Examples 5 and 6 were blends of Oil B with, respectively, 0.1 wt% and 0.5 wt%, of pentamethyl piperidine.
• Comparative Example 3 was a blend of 99.9 wt% Oil B with 0.1 wt% of tetramethyl piperidine.
• Comparative Examples 4 and 5 were a blend of 99.9 wt% Oil B with, respectively, 0.1 wt% 2,2,6,6-tetramethylpiperidin-1-yl) oxy (abbreviated in Table 1 to "TEMPO”) and 0.1 wt% 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl (abbreviated in Table 1 to “TEMPOL”).
• TEMPO 2,2,6,6-tetramethylpiperidin-1-yl) oxy
• TEMPOL 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl
• compositions of the Examples and the Comparative Examples were obtained by mixing the oils (Oil A/Oil B) with said hindered amine light stabilizer using conventional lubricant blending procedures.
• each of the lubricating oil compositions were subjected to ASTM D6186 which is a standard test method for measuring oxidation induction time of a lubricating oil composition by Pressure Differential Scanning Calorimetry (pDSC).
• the pressure and temperature conditions which were used are as set out in Table 1.
• the results of these measurements are set out in Table 1.
• Example 5 demonstrates that the use of pentamethyl piperidine at a treat rate of 0.1 wt% reduces the loss in oxidative stability when a lubricating composition is diluted with 10wt% FAME.
• Example 6 of the present set of examples didn't show a benefit in terms of oxidative stability. While not wishing to be limited by theory, this could be attributed to solubility constraints of using pentamethyl piperidine at a higher treat rate, however the person skilled in the art would realise that this could be fixed by, for example, adjusting the temperature that is used to make the lubricating composition.
• Comparative Example 3 containing tetramethyl piperidine did not show any benefit in terms of reducing the loss in oxidative stability when a lubricating composition is diluted with FAME. This is believed to be due to the tetramethyl piperidine converting to the nitroxide (i.e. TEMPO), which itself doesn't appear to provide a benefit in terms of reducing the loss in oxidative stability when the lubricating composition is diluted with FAME (see Comparative Example 4).
• TEMPO nitroxide

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• 2013
  • 2013-06-18 EP EP13172545.9A patent/EP2816097A1/fr not_active Withdrawn

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