Patent Application
20090075853
1. Technical Field
The present disclosure is directed to a release additive liquid concentrate and methods for use thereof in an oil filter system. More particularly, this disclosure is directed to a method for extending an oil drain interval of an engine having an oil filter including a release additive including at least one detergent; and at least one antioxidant.
2. Background and Summary
During the combustion process in internal combustion engines, mineral and organic acidic by-products are produced. Concurrently, other acidic products may be generated by the degradation of lubricants used in internal combustion engines. Such by-products may lead to the formation of high temperature deposits, low temperature sludge formation and corrosion of various engine parts which ultimately may lead to increased wear of lubricated engine components. Basic substances are typically included in lubricants to neutralize the acidic products in order to break the cycle of sludge and high temperature deposit formation and accelerated wear of engine parts.
However, the ability to retain the basicity of the lubricant composition throughout its useful life is a problem. Failure to maintain an oil's basicity may dramatically increase a vehicle's downtime, for example by requiring more frequent oil changes than the recommended oil change interval, or dramatically shorten an engine's life.
Accordingly, an ability to retain the basicity in a lubricant composition over an extended period of time may, for example, dramatically reduce the risk of sludge and high temperature deposit formation and corrosion plus reduce maintenance time and extend engine life.
With regard to the foregoing, and in accordance with exemplary embodiments of the disclosure, there is provided a slow release liquid additive concentrate for use in an engine oil filter and a method for extending an oil drain interval for an engine. The additive concentrate has therein at least one detergent and at least one antioxidant. The additive concentrate also has a tan delta of greater than about 5.
In another exemplary embodiment, the disclosure provides a method of increasing an oil drain interval in a vehicle. The method includes providing to the vehicle an oil filter having thereing a release additive liquid for predetermined periodic release into an engine oil. The release additive liquid includes at least one detergent and at least one antioxidant, and the release additive liquid has a tan delta of greater than about 5.
An advantage of the additives and methods of the disclosure is that an oil drain interval for an engine may be significantly enhanced without the need for specialized processing conditions for the additive concentrate. In other words, liquid rather than solid or semisolid additive concentrates may be advantageously used to provide a controlled release of the additive to a lubricant oil system through an oil filter. Additional objects and advantages of the disclosure will be set forth in part in the description which follows, and/or can be learned by practice of the disclosure. The objects and advantages of the disclosure may be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure, as claimed.
For the purposes of this disclosure, the “tan delta” of a fluid is a rheological property of the fluid and is defined as a ratio of loss modulus to storage modulus of a fluid as determined by small amplitude oscillatory shear testing of the fluid. Accordingly, the additive concentrate is substantially in liquid form and has a tan delta of about 5 or more.
In accordance with the present disclosure, the non-basic oils/acidic oils in engines may be decreased by using the liquid additive concentrate provided to the oil through a filter thereby effecting at least one of the following properties: reducing the risk of corrosion, reducing the maintenance time on a vehicle, and extending the engine life. Moreover, the basicity of the lubricating composition may be either maintained or increased by contacting the oil with a predetermined amount of the additive concentrate. It is believed, without being limited to any particular theory, that the use of the disclosed additive concentrate may achieve at least one of the above disclosed properties because a detergent in the additive concentrate is slowly released into the lubricating composition thereby retaining and/or increasing the TBN of the lubricating composition over the life of the lubricating composition. The detergent suitably has a TBN of at least about 100. One of ordinary skill in the art would understand that the life of the lubricating composition is dependent upon several factors including, but not limited to, engine operation, engine type, engine service, mileage of the vehicle, quality of the base oil in the lubricating composition, etc.
Engines that may benefit by the use the additive concentrate include, but are not limited to internal combustion engines, stationary engines, generators, diesel and/or gasoline engines, on highway and/or off highway engines, two-cycle engines, aviation engines, piston engines, marine engines, railroad engines, biodegradable fuel engines and the like. In one embodiment, the engine may be equipped with after-treatment devices, such as exhaust gas recirculation systems, catalytic converters, diesel particulate filters, NOx traps, and the like.
The term “release” as used herein is understood to mean that the components of the additive composition are released over an extended period of time, e.g., over the life of the lubricating composition. The release rate may be moderated by several factors, such as, the location of the additive composition in the lubrication system, the additive composition formulation, the form of the composition, and/or the mode of addition of the additive composition into a lubricating composition. One of ordinary skill in the art may modify any and/or all of the above factors in order to obtain the desired release rate of the additive composition.
The additive concentrate may be located anywhere within a lubrication system so long as the additive concentrate will be in contact with a lubricating composition. For example, the additive concentrate may be located in at least one of a filter, drain pan, oil bypass loop, canister, housing, reservoir, compartment of a filter, canister in a filter, canister in a bypass system, and the like. In an embodiment, the lubrication system comprises an oil filter and the oil filter includes additive concentrate disclosed herein.
In another embodiment, the oil filter may comprise a housing, such as a sleeve or cup, that may be partitioned, for example with a non-diffusable barrier, thereby creating at least one additive compartment. The filter may be a desirable location to place the additive concentrate because the additive composition and/or spent additive composition may easily be removed when the filter is removed and then replaced with a new and/or recycled additive composition.
Moreover, the additive concentrate may be present in an additive compartment of the oil filter, wherein the additive compartment comprises at least one additive metering hole for adding a predetermined amount of the additive concentrate to oil over a period of time. The at least one hole can be covered with a fatty substance, such as wax or other oil soluble or meltable material for shipping purposes The fatty substance may erode, degrade, or melt away over a period of time once it is in contact with hot oil so that the additive concentrate is released into a lubricant composition. It is envisioned that the fatty substance will not be detrimental to any and/or all of the properties of the additive concentrate or lubricant composition.
In yet another embodiment, the additive concentrate may be located in another location within the lubrication system. For example, the release additive may be located outside of an oil filter on the “dirty” side thereof or may be located outside of the oil filter on the “clean” side thereof. Regardless of the location of the additive concentrate, it contemplated that the additive concentrate is released into a lubricating composition over a predetermined period of time, such as over the life of the lubricating composition.
The amount additive concentrate that is released into the lubricating composition may be any effective amount so long as the TBN of the lubricating composition is maintained or increased over the life of the lubricating composition. For example, the TBN of the lubricating composition may be maintained and/or increased by combining/mixing/blending the disclosed additive concentrate with the lubricating composition. By maintaining or increasing the TBN of the lubricating composition, it is believed that the engine oil drain interval may be extended beyond current manufacturer's recommendations.
In an embodiment, for a passenger car, the engine oil drain interval may be extended beyond about 7,500 miles, such as beyond about 10,000 miles for normal service. In another embodiment, for a truck in a trucking fleet, the engine oil drain interval may be extended beyond about 15,000 miles, for example up to about 25,000, and as a further example beyond about 35,000 miles for normal fleet service.
A lubricating composition may comprise a minor amount of the additive concentrate. A “minor amount” as used herein is understood to mean less than about 50%, such as for example less than about 40%, and as a further example from less than about 30% by weight relative to the total weight in the lubricating composition. In an embodiment, the additive concentrate may be provided in an amount ranging from about 0.0001% to about 49.9% by weight relative to a total weight of the lubricating composition.
In accordance with the present disclosure, the additive concentrate may comprise at least one detergent having a TBN of at least about 100, at least one antioxidant, and optionally, at least one viscosity index improver. As used herein, the “detergent” is understood to mean a detergent chosen from sulfonates, phenates, salicylates, carboxylates, and combinations thereof, wherein the detergent has a TBN of at least about 100. Accordingly, the detergent may be selected from overbased calcium sulfonate detergents which are commercially-available, overbased detergents containing alkali and alkali earth metals such as Mg, Ba, Li, Sr, Na, Ca, and K, and mixtures thereof. Non-limiting examples of overbased alkali and alkali earth metal detergents include sodium sulfonates, sodium carboxylates, sodium salicylates, sodium phenates, sulfurized sodium phenates, calcium sulfonates, calcium carboxylates, calcium salicylates, calcium phenates, sulfurized calcium phenates, lithium sulfonates, lithium carboxylates, lithium salicylates, lithium phenates, sulfurized lithium phenates, magnesium sulfonates, magnesium carboxylates, magnesium salicylates, magnesium phenates, sulfurized magnesium phenates, potassium sulfonates, potassium carboxylates, potassium salicylates, potassium phenates, sulfurized potassium phenates.
Suitable detergents may also be selected from a metal salt of a Mannich condensation product. The Mannich condensation product that may be used as the detergent may be prepared using an alkyl phenol, a formaldehyde or an aldehyde and a nitrogen base selected from ammonia, a lower alkyl amine, a polyamine and mixtures thereof.
The alkyl group on the alkyl phenol used for the preparation of the Mannich condensation product may be a branched chain alkyl group, a linear chain alkyl group or mixtures thereof. Preferably the alkyl group is a branched chain alkyl group containing from about 4 carbon atoms to about 60 carbon atoms. More preferably 6 carbon atoms to about 40 carbon atoms and most preferably from about 8 carbon atoms to about 20 carbon atoms.
Each of the foregoing detergents may be used alone or combinations of two or more of the foregoing detergents may be used. Commercially-available overbased detergent products may be formed by reacting carbon dioxide with mixtures of lime (calcium hydroxide) and an alkyl benzene sulfonate soap to form calcium carbonate-containing micelles. More than an equivalent amount of lime and carbon dioxide may be used so that the product detergent becomes basic in character.
Such materials may be conveniently described in terms of a total base number (“TBN”), which is a measure of the base capacity of the detergent. Detergents suitable for use herein can have TBN's ranging from about 100 to about 600, for example from about 200 to about 500, and for example from about 300 to about 400. When mixtures of detergents are used, it is desirable for at least one of the detergents to have a TBN value of at least 300.
The detergent may be present in the additive concentrate in any effective amount, which may be readily determined by one of ordinary skill in the art, such as from about 60 wt. % to about 90 wt. %, and for example, from about 70 wt. % to about 80 wt. %, relative to a total weight of the additive concentrate. Moreover, the detergent may have an active ingredient content of about 60% or more. As used herein, the “active ingredient content” refers to an amount of detergent compound relative to inactive components in the detergent, such as process oils and diluents.
The additive concentrate may further comprise at least one antioxidant. There is no particular restriction on the type of antioxidant that can be used according to the present disclosure. Suitable antioxidants for use herein include, but are not limited to, alkyl-substituted phenols such as 2,6-di-tertiary butyl-4-methyl phenol, phenate sulfides, phosphosulfurized terpenes, sulfurized esters, aromatic amines, diphenyl amines, alkylated diphenyl amines, hindered phenols, and mixtures thereof.
In one exemplary embodiment, the antioxidant may be an amine, such as diarylamines and alky derivatives of diarylamines (e.g., diphenylamine, bis-nonylated diphenylamine, nonyl diphenylamine, octyl diphenylamine, bis-octylated diphenylamine, bis-decylated diphenylamine, decyl diphenylamine), and mixtures thereof.
In another exemplary embodiment, the antioxidant may be a sterically hindered phenol, such as 2,6-di-tert-butylphenol, 4-methyl-2,6-di-tert-butyl-phenol, 4-ethyl-2,6-di-tert-butylphenol, 4-propyl-2,6-di-tert-butylphenol, 4-butyl-2,6-di-tert-butylphenol 2,6-di-tert-butylphenol, 4-pentyl-2,6-di-tert-butylphenol, 4-hexyl-2,6-di-tert-butylphenol, 4-heptyl-2,6-di-tert-butylphenol, 4-(2-ethylhexyl)-2,6-di-tert-butylphenol, 4-octyl-2,6-di-tert-butylphenol, 4-nonyl-2,6-di-tert-butylphenol, 4-decyl-2,6-di-tert-butylphenol, 4-undecyl-2,6-di-tert-butylphenol, 4-dodecyl-2,6-di-tert-butylphenol, 4-tridecyl-2,6-di-tert-butylphenol, 4-tetradecyl-2,6-di-tert-butylphenol, methylene-bridged sterically hindered phenols such as 4,4-methylenebis(6-tert-butyl-o-cresol), 4,4-methylenebis(2-tert-amyl-o-cresol), 2,2-methylenebis(4-methyl-6-tert-butylphenol), 4,4-methylene-bis(2,6-di-tertbutylphenol), and mixtures thereof. Moreover, sterically hindered phenol derivatives may be suitable for use herein, including functionalized hindered phenols. Functional groups that can be used to functionalize hindered phenols can include, but are not be limited to, esters, thioesters, alkyl groups, amines, ketones, amides, sulfoxides, and sulfones.
Another suitable antioxidant may be a hindered, ester-substituted phenol, which may be prepared by heating a 2,6-dialkylphenol with an acrylate ester under base catalysis conditions, such as aqueous KOH.
The antioxidant may be present in the additive concentrate in any effective amount, such as from about 10 wt. % to about 40 wt. %, and for example from about 15 wt. % to about 30 wt. %, relative to the total weight of the release additive composition.
The additive concentrate may optionally include one or more viscosity modifiers (VM). Viscosity modifiers (VM) function to impart high and low temperature operability to a lubricating oil. Suitable viscosity modifiers are nitrogen-free viscosity modifiers that may be selected from polyisobutylene, copolymers of ethylene and propylene and higher alpha-olefins, polymethacrylates, polyalkylmethacrylates, methacrylate copolymers, copolymers of an unsaturated dicarboxylic acid and a vinyl compound, inter polymers of styrene and acrylic esters, and partially hydrogenated copolymers of styrene/isoprene, styrene/butadiene, and isoprene/butadiene, as well as the partially hydrogenated homopolymers of butadiene and isoprene and isoprene/divinylbenzene.
The amount of viscosity modifier in the additive concentrate may vary over a wide range. However, it is desirable to include an amount of viscosity modifier that is suitable to provide the predetermined amount of additive concentrate to the lubricant composition over a predetermined period of time. The amount of viscosity modifier should be less than an amount that causes the additive concentrate to exhibit gel, solid, or semi-solid properties. Accordingly, the additive concentrate may contain from about 0 to about 20 weight percent of the viscosity modifier based on the total weight of the additive concentrate.
Lubricating compositions, such as modern motor oils, may be made by combining a pre-formed additive package with a refined or synthetic base oil stock. A lubricating composition may comprise various different lubricant additive packages. Because lubricant additives may be easier to handle and measure in liquid form those additives which are normally solid are typically dissolved in small amounts of base oil stock. In an embodiment of the disclosure, the additive concentrate may comprise an oil content of less than about 50 wt. %, such as from about 5 wt. % to about 30 wt. % based on the total weight of the additive concentrate.
Base oils suitable for use in formulating the additive concentrates may be selected from any of the synthetic or mineral oils or mixtures thereof. Mineral oils include animal oils and vegetable oils (e.g., castor oil, lard oil) as well as other mineral lubricating oils such as liquid petroleum oils and solvent treated or acid-treated mineral lubricating oils of the paraffinic, naphthenic or mixed paraffinic-naphthenic types. Oils derived from coal or shale are also suitable. Further, oils derived from a gas-to-liquid process are also suitable.
The base oil may have any desired viscosity that is suitable for the intended purpose. Examples of suitable engine oil kinematic viscosities may range from about 2 to about 150 cSt and, as a further example, from about 5 to about 15 cSt at 100° C. Thus, for example, base oils may be selected to provide the additive concentrate with a viscosity ranging from about 10 to about 50 cSt at 100° C.
Non-limiting examples of synthetic oils include hydrocarbon oils such as polymerized and interpolymerized olefins (e.g., polybutylenes, polypropylenes, propylene isobutylene copolymers, etc.); polyalphaolefins such as poly(1-hexenes), poly-(1-octenes), poly(1-decenes), etc. and mixtures thereof, alkylbenzenes (e.g., dodecylbenzenes, tetradecylbenzenes, di-nonylbenzenes, di-(2-ethylhexyl)benzenes, etc.); polyphenyls (e.g., biphenyls, terphenyl, alkylated polyphenyls, etc.); alkylated diphenyl ethers and alkylated diphenyl sulfides and the derivatives, analogs and homologs thereof and the like.
Alkylene oxide polymers and interpolymers and derivatives thereof where the terminal hydroxyl moieties have been modified by esterification, etherification, etc., constitute another class of known synthetic oils that can be used. Such oils are exemplified by the oils prepared through polymerization of ethylene oxide or propylene oxide, the alkyl and aryl ethers of these polyoxyalkylene polymers (e.g., methyl-polyisopropylene glycol ether having an average molecular weight of about 1000, diphenyl ether of polyethylene glycol having a molecular weight of about 500-1000, diethyl ether of polypropylene glycol having a molecular weight of about 1000-1500, etc.) or mono- and polycarboxylic esters thereof, for example, the acetic acid esters, mixed C3-8 fatty acid esters, or the C13 Oxo acid diester of tetraethylene glycol.
Another class of synthetic oils that may be used includes the esters of dicarboxylic acids (e.g., phthalic acid, succinic acid, alkyl succinic acids, alkenyl succinic acids, maleic acid, azelaic acid, suberic acid, sebacic acid, fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkyl malonic acids, alkenyl malonic acids, etc.) with a variety of alcohols (e.g., butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether, propylene glycol, etc.) Specific examples of these esters include dibutyl adipate, di(2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl sebacate, the 2-ethylhexyl diester of linoleic acid dimer, the complex ester formed by reacting one mole of sebacic acid with two moles of tetraethylene glycol and two moles of 2-ethylhexanoic acid and the like.
Esters useful as synthetic oils also include those made from C5-12 monocarboxylic acids and polyols and polyol ethers such as neopentyl glycol, trimethylol propane, pentaerythritol, dipentaerythritol, tripentaerythritol, etc.
Hence, the base oil used which may be used to make the compositions as described herein can be selected from any of the base oils in Groups I-V as specified in the American Petroleum Institute (API) Base Oil Interchangeability Guidelines. Such base oil groups are as follows:
Group I contain less than 90% saturates and/or greater than 0.03% sulfur and have a viscosity index greater than or equal to 80 and less than 120; Group II contain greater than or equal to 90% saturates and less than or equal to 0.03% sulfur and have a viscosity index greater than or equal to 80 and less than 120; Group III contain greater than or equal to 90% saturates and less than or equal to 0.03% sulfur and have a viscosity index greater than or equal to 120; Group IV are polyalphaolefins (PAO); and Group V include all other basestocks not included in Group I, II, III or IV.
The test methods used in defining the above groups are ASTM D2007 for saturates; ASTM D2270 for viscosity index; and one of ASTM D2622, 4294, 4927 and 3120 for sulfur.
Group IV basestocks, i.e. polyalphaolefins (PAO) include hydrogenated oligomers of an alpha-olefin, the most important methods of oligomerisation being free radical processes, Ziegler catalysis, and cationic, Friedel-Crafts catalysis.
The polyalphaolefins typically have viscosities in the range of 2 to 100 cSt at 100° C., for example 4 to 8 cSt at 100° C. They can, for example, be oligomers of branched or straight chain alpha-olefins having from about 2 to about 30 carbon atoms, non-limiting examples include polypropenes, polyisobutenes, poly-1-butenes, poly-1-hexenes, poly-1-octenes and poly-1-decene. Included are homopolymers, interpolymers and mixtures.
Regarding the balance of the basestock referred to above, a “Group I basestock” also includes a Group I basestock with which basestock(s) from one or more other groups can be admixed, provided that the resulting admixture has characteristics falling within those specified above for Group I basestocks.
Exemplary basestocks include Group I basestocks and mixtures of Group TI basestocks with Group I bright stock.
Basestocks suitable for use herein may be made using a variety of different processes including but not limited to distillation, solvent refining, hydrogen processing, oligomerisation, esterification, and re-refining.
The base oil may be an oil derived from Fischer-Tropsch synthesized hydrocarbons. Fischer-Tropsch synthesized hydrocarbons can be made from synthesis gas containing H2 and CO using a Fischer-Tropsch catalyst. Such hydrocarbons typically require further processing in order to be useful as the base oil. For example, the hydrocarbons can be hydroisomerized using processes disclosed in U.S. Pat. No. 6,103,099 or 6,180,575; hydrocracked and hydroisomerized using processes disclosed in U.S. Pat. No. 4,943,672 or 6,096,940; dewaxed using processes disclosed in U.S. Pat. No. 5,882,505; or hydroisomerized and dewaxed using processes disclosed in U.S. Pat. No. 6,013,171; 6,080,301; or 6,165,949.
Unrefined, refined and rerefined oils, either mineral or synthetic (as well as mixtures of two or more of any of these) of the type disclosed hereinabove may be used in the base oils. Unrefined oils are those obtained directly from a mineral or synthetic source without further purification treatment. For example, a shale oil obtained directly from retorting operations, a petroleum oil obtained directly from primary distillation or ester oil obtained directly from an esterification process and used without further treatment would be an unrefined oil. Refined oils are similar to the unrefined oils except they have been further treated in one or more purification steps to improve one or more properties. Many such purification techniques are known to those skilled in the art such as solvent extraction, secondary distillation, acid or base extraction, filtration, percolation, etc. Rerefined oils are obtained by processes similar to those used to obtain refined oils applied to refined oils which have been already used in service. Such rerefined oils are also known as reclaimed or reprocessed oils and often are additionally processed by techniques directed to removal of spent additives, contaminants, and oil breakdown products.
The following example is illustrative of the invention and its advantageous properties. In this example as well as elsewhere in this application, all parts and percentages are by weight unless otherwise indicated. It is intended that this example is being presented for the purpose of illustration only and is not intended to limit the scope of the invention disclosed herein.
A additive concentrate was made by mixing 75 wt. % of an overbased detergent, such as a 500 TBN calcium sulfonate detergent having about 64% active ingredient content, with 25 wt. % of an antioxidant, such as an alkylated diphenylamine in an amount of base oil sufficient to provide the additive concentrate with less than about 30 weight percent base oil.
It is noted that, as used in this specification and the appended claims, the singular forms “a,” “an,” and “the,” include plural referents unless expressly and unequivocally limited to one referent. Thus, for example, reference to “an antioxidant” includes two or more different antioxidants. As used herein, the term “include” and its grammatical variants are intended to be non-limiting, such that recitation of items in a list is not to the exclusion of other like items that can be substituted or added to the listed items
For the purposes of this specification and appended claims, unless otherwise indicated, all numbers expressing quantities, percentages or proportions, and other numerical values used in the specification and claims, are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by the present disclosure. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.
While particular embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are or can be presently unforeseen can arise to applicants or others skilled in the art. Accordingly, the appended claims as filed and as they can be amended are intended to embrace all such alternatives, modifications variations, improvements, and substantial equivalents.
