Patent Application
20090011963
The present disclosure relates to a lubricant system comprising an engine oil, a transmission fluid, and a gear oil. There is also disclosed a kit comprising the disclosed compositions. Moreover there is disclosed a method of improving fuel economy.
Over the years, the fuel economy of vehicles has been improving due to the collective effort of the automobile manufacturers, fuel suppliers, lubricant suppliers, and additive suppliers. As a result of government regulations, newer automobiles are being manufactured with an eye toward increasing fuel economy. Besides reducing the size and weight of the automobile, another way to improve fuel economy is to reduce friction in an engine. A reduction in engine friction can result in a decrease in the amount of fuel consumed by that engine. Also, new and advanced transmission systems often involve high energy requirements. The high speeds generated during engagement and disengagement of newer transmission systems mean that a friction material must be able to maintain a relatively constant friction throughout the engagement. It is important that frictional engagement be relatively constant over a wide range of speeds and temperatures in order to minimize “shuddering” of materials during transmission power shift from one gear to another. Hence, there is a need for transmission fluids that can provide improved fuel economy.
The lubricant industry has also recognized the need for enhanced gear lubricants to improve fuel economy. Current gear lubricants are exposed to severe operating conditions and longer drain intervals and should still provide the ability to cool, lubricate, and protect moving surfaces of gears.
Hence, what is needed is a multi-component approach that can provide improved fuel economy, such as a lubricant system comprising an engine oil, a transmission oil, and a gear oil.
In accordance with the disclosure, there is disclosed a lubricant system comprising an engine oil comprising at least one additive chosen from a viscosity index improver, a dispersant, a detergent, an antioxidant, and an antiwear compound; a transmission fluid comprising at least one additive chosen from a dispersant and a pour-point depressant; and a gear oil comprising at least one additive chosen from a viscosity index improver, an extreme pressure agent, and a dispersant.
According to another aspect, there is disclosed a method of improving fuel economy of a vehicle comprising providing to the vehicle a lubricant system comprising an engine oil comprising at least one additive chosen from a viscosity index improver, a dispersant, a detergent, an antioxidant, and an antiwear compound; a transmission fluid comprising at least one additive chosen from a dispersant and a pour-point depressant; and a gear oil comprising at least one additive chosen from a viscosity index improver, an extreme pressure agent, and a dispersant.
According to yet another aspect, there is disclosed a multi-component kit comprising a first component comprising an engine oil comprising at least one additive chosen from a viscosity index improver, a dispersant, a detergent, an antioxidant, and an antiwear compound; a second component comprising a transmission fluid comprising at least one additive chosen from a dispersant and a pour-point depressant; and a third component comprising a gear oil comprising at least one additive chosen from a viscosity index improver, an extreme pressure agent, and a dispersant.
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.
The present disclosure relates to a lubricant system comprising an engine oil, a transmission fluid, and a gear oil, wherein the engine oil comprises at least one additive chosen from a viscosity index improver, a dispersant, a detergent, an antioxidant, and an antiwear compound; the transmission fluid comprises at least one additive chosen from a dispersant and a pour-point depressant; and the gear oil comprises at least one additive chosen from a viscosity index improver, an extreme pressure agent, and a dispersant. In an aspect, the lubricant system can provide improved fuel economy as compared to a lubricant system devoid of at least one of the engine oil, the transmission fluid, and the gear oil.
The dispersant for use in the disclosed lubricant system can comprise at least one of succinimide, boron-containing succinimide, phosphorus-containing succinimide, succinic acid ester, succinic ester-amides, Mannich base, hydrocarbyl polyamine, polymeric polyamine, functionalized olefin copolymer, and polyalkyl (meth)acrylate copolymers. The phosphorus or boron-containing dispersants can be formed by phosphorylating or boronating a dispersant having basic nitrogen and/or at least one hydroxyl group in the molecule, such as a succinimide dispersant, succinic ester dispersant, succinic ester-amide dispersant, Mannich base dispersant, hydrocarbyl polyamine dispersant, or polymeric polyamine dispersant.
Succinimides such as hydrocarbyl-substituted succinimides can be made from hydrocarbyl-substituted succinic acylating agents. The hydrocarbyl-substituted succinic acylating agents can include, but are not limited to, hydrocarbyl-substituted succinic acids, hydrocarbyl-substituted succinic anhydrides, the hydrocarbyl-substituted succinic acid halides (for example, the acid fluorides and acid chlorides), and the esters of the hydrocarbyl-substituted succinic acids and lower alcohols (e.g., those containing up to 7 carbon atoms), that is, hydrocarbyl-substituted compounds which can function as carboxylic acylating agents.
Hydrocarbyl-substituted acylating agents can be made by reacting a polyolefin or chlorinated polyolefin of appropriate molecular weight with maleic anhydride. Similar carboxylic reactants can be used to make the acylating agents. Such reactants can include, but are not limited to, maleic acid, fumaric acid, malic acid, tartaric acid, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride, mesaconic acid, ethylmaleic anhydride, dimethylmaleic anhydride, ethylmaleic acid, dimethylmaleic acid, hexylmaleic acid, and the like, including the corresponding acid halides and lower aliphatic esters.
The molecular weight of the olefin can vary depending upon the intended use of the substituted succinic anhydrides. Typically, the substituted succinic anhydrides can have a hydrocarbyl group of from about 8 to about 500 carbon atoms. However, substituted succinic anhydrides used to make dispersants can typically have a hydrocarbyl group of about 40 to about 500 carbon atoms. With high molecular weight substituted succinic anhydrides, it is more accurate to refer to number average molecular weight (Mn) because the olefins used to make these substituted succinic anhydrides can include a mixture of different molecular weight components resulting from the polymerization of low molecular weight olefin monomers such as ethylene, propylene and isobutylene.
The mole ratio of maleic anhydride to olefin can vary widely. It can vary, for example, from about 5:1 to about 1:5, or for example, from about 1:1 to about 3:1. With olefins such as polyisobutylene having a number average molecular weight of about 500 to about 7000, or as a further example, about 800 to about 3000 or higher and the ethylene-alpha-olefin copolymers, the maleic anhydride can be used in stoichiometric excess, e.g. about 1.1 to about 3 moles maleic anhydride per mole of olefin. The unreacted maleic anhydride can be vaporized from the resultant reaction mixture.
Polyalkenyl succinic anhydrides can be converted to polyalkyl succinic anhydrides by using conventional reducing conditions such as catalytic hydrogenation. For catalytic hydrogenation, a suitable catalyst is palladium on carbon. Likewise, polyalkenyl succinimides can be converted to polyalkyl succinimides using similar reducing conditions.
The polyalkyl or polyalkenyl substituent on the succinic anhydrides employed herein can be generally derived from polyolefins which are polymers or copolymers of mono-olefins, particularly 1-mono-olefins, such as ethylene, propylene, and butylene. The mono-olefin employed can have about 2 to about 24 carbon atoms, or as a further example, about 3 to about 12 carbon atoms. Other suitable mono-olefins include propylene, butylene, particularly isobutylene, 1-octene, and 1-decene. Polyolefins prepared from such mono-olefins include polypropylene, polybutene, polyisobutene, and the polyalphaolefins produced from 1-octene and 1-decene.
In some aspects, the dispersant can include one or more alkenyl succinimides of an amine having at least one primary amino group capable of forming an imide group. The alkenyl succinimides can be formed by conventional methods such as by heating an alkenyl succinic anhydride, acid, acid-ester, acid halide, or lower alkyl ester with an amine containing at least one primary amino group. The alkenyl succinic anhydride can be made readily by heating a mixture of polyolefin and maleic anhydride to about 180°-220° C. The polyolefin can be a polymer or a copolymer of a lower monoolefin such as ethylene, propylene, isobutene, and the like, having a number average molecular weight in the range of about 300 to about 3000 as determined by gel permeation chromatography (GPC).
Amines which can be employed in forming the dispersant include any that have at least one primary amino group which can react to form an imide group and at least one additional primary or secondary amino group and/or at least one hydroxyl group. A few representative examples are: N-methyl-propanediamine, N-dodecylpropanediamine, N-aminopropyl-piperazine, ethanolamine, N-ethanol-ethylenediamine, and the like.
Suitable amines can include alkylene polyamines, such as propylene diamine, dipropylene triamine, di-(1,2-butylene)triamine, and tetra-(1,2-propylene)pentamine. A further example includes the ethylene polyamines which can be depicted by the formula H2N(CH2CH2—NH)nH, wherein n can be an integer from about one to about ten. These include: ethylene diamine, diethylene triamine (DETA), triethylene tetramine (TETA), tetraethylene pentamine (TEPA), pentaethylene hexamine (PEHA), and the like, including mixtures thereof in which case n is the average value of the mixture. Such ethylene polyamines have a primary amine group at each end so they can form mono-alkenylsuccinimides and bis-alkenylsuccinimides. Commercially available ethylene polyamine mixtures can contain minor amounts of branched species and cyclic species such as N-aminoethyl piperazine, N,N′-bis(aminoethyl)piperazine, N,N′-bis(piperazinyl)ethane, and like compounds. The commercial mixtures can have approximate overall compositions falling in the range corresponding to diethylene triamine to tetraethylene pentamine. The molar ratio of polyalkenyl succinic anhydride to polyalkylene polyamines can be from about 1:1 to about 3:1.
In some aspects, the dispersant can include the products of the reaction of a polyethylene polyamine, e.g. triethylene tetramine or tetraethylene pentamine, with a hydrocarbon substituted carboxylic acid or anhydride made by reaction of a polyolefin, such as polyisobutene, of suitable molecular weight, with an unsaturated polycarboxylic acid or anhydride, e.g., maleic anhydride, maleic acid, fumaric acid, or the like, including mixtures of two or more such substances.
Polyamines that are also suitable in preparing the dispersants described herein include N-arylphenylenediamines, such as N-phenylphenylenediamines, for example, N-phenyl-1,4-phenylenediamine, N-phenyl-1,3-phenylendiamine, and N-phenyl-1,2-phenylenediamine; aminothiazoles such as aminothiazole, aminobenzothiazole, aminobenzothiadiazole and aminoalkylthiazole; aminocarbazoles; aminoindoles; aminopyrroles; amino-indazolinones; aminomercaptotriazoles; aminopyrimidines; aminoalkyl imidazoles, such as 1-(2-aminoethyl)imidazole, 1-(3-aminopropyl)imidazole; and aminoalkyl morpholines, such as 4-(3-aminopropyl)morpholine. These polyamines are described in more detail in U.S. Pat. Nos. 4,863,623 and 5,075,383, the disclosures of which are hereby incorporated by reference herein.
Additional polyamines useful in forming the hydrocarbyl-substituted succinimides include polyamines having at least one primary or secondary amino group and at least one tertiary amino group in the molecule as taught in U.S. Pat. Nos. 5,634,951 and 5,725,612, the disclosures of which are hereby incorporated by reference herein. Non-limiting examples of suitable polyamines include N,N,N″,N″-tetraalkyldialkylenetriamines (two terminal tertiary amino groups and one central secondary amino group), N,N,N′N″-tetraalkyltrialkylenetetramines (one terminal tertiary amino group, two internal tertiary amino groups, and one terminal primary amino group), N,N,N′,N″, N′″-pentaalkyltrialkylenetetramines (one terminal tertiary amino group, two internal tertiary amino groups, and one terminal secondary amino group), tris(dialkylaminoalkyl)aminoalkylmethanes (three terminal tertiary amino groups and one terminal primary amino group), and like compounds, wherein the alkyl groups are the same or different and typically contain no more than about 12 carbon atoms each, and which can contain from about 1 to about 4 carbon atoms each. As a further example, these alkyl groups can be methyl and/or ethyl groups. Polyamine reactants of this type can include dimethylaminopropylamine (DMAPA) and N-methyl piperazine.
Hydroxyamines suitable for herein include compounds, oligomers or polymers containing at least one primary or secondary amine capable of reacting with the hydrocarbyl-substituted succinic acid or anhydride. Examples of hydroxyamines suitable for use herein include aminoethylethanolamine (AEEA), aminopropyldiethanolamine (APDEA), ethanolamine, diethanolamine (DEA), partially propoxylated hexamethylene diamine (for example HMDA-2PO or HMDA-3PO), 3-amino-1,2-propanediol, tris(hydroxymethyl)aminomethane, and 2-amino-1,3-propanediol.
The mole ratio of amine to hydrocarbyl-substituted succinic acid or anhydride can range from about 1:1 to about 3:1. Another example of a mole ratio of amine to hydrocarbyl-substituted succinic acid or anhydride may range from about 1.5:1 to about 2:1.
The foregoing dispersant can also be a post-treated dispersant made, for example, by treating the dispersant with maleic anhydride and boric acid as described, for example, in U.S. Pat. No. 5,789,353, or by treating the dispersant with nonylphenol, formaldehyde, and glycolic acid as described, for example, in U.S. Pat. No. 5,137,980, the disclosures of which are hereby incorporated by reference in their entirety.
The Mannich base dispersants can be a reaction product of an alkyl phenol, typically having a long chain alkyl substituent on the ring, with one or more aliphatic aldehydes containing from about 1 to about 7 carbon atoms (for example, formaldehyde and derivatives thereof), and polyamines (especially polyalkylene polyamines). For example, a Mannich base dispersant can be formed by condensing about one molar proportion of long chain hydrocarbon-substituted phenol with from about 1 to about 2.5 moles of formaldehyde and from about 0.5 to about 2 moles of polyalkylene polyamine.
Hydrocarbon sources for preparation of the Mannich polyamine dispersants can be those derived from substantially saturated petroleum fractions and olefin polymers, such as polymers of mono-olefins having from about 2 to about 6 carbon atoms. The hydrocarbon source generally contains, for example, at least about 40 carbon atoms, and as a further example, at least about 50 carbon atoms to provide substantial oil solubility to the dispersant. The olefin polymers having a GPC number average molecular weight range from about 600 to about 5,000 can be suitable. However, polymers of higher molecular weight can also be used. Suitable hydrocarbon sources can be isobutylene polymers and polymers made from a mixture of isobutene and a raffinate stream.
Suitable Mannich base dispersants can be Mannich base ashless dispersants formed by condensing about one molar proportion of long chain hydrocarbon-substituted phenol with from about 1 to about 2.5 moles of formaldehyde and from about 0.5 to about 2 moles of polyalkylene polyamine.
Polymeric polyamine dispersants suitable as the dispersants are polymers containing basic amine groups and oil solubilizing groups (for example, pendant alkyl groups having at least about 8 carbon atoms). Such materials are illustrated by interpolymers formed from various monomers such as decyl methacrylate, vinyl decyl ether or relatively high molecular weight olefins, with aminoalkyl acrylates and aminoalkyl acrylamides. Examples of polymeric polyamine dispersants are set forth in U.S. Pat. Nos. 3,329,658; 3,449,250; 3,493,520; 3,519,565; 3,666,730; 3,687,849; and 3,702,300. Polymeric polyamines can include hydrocarbyl polyamines wherein the hydrocarbyl group is composed of the polymerization product of isobutene and a raffinate stream as described above. PIB-amine and PIB-polyamines may also be used.
Methods for the production of dispersants as described above are known to those skilled in the art and are reported in the patent literature. For example, the synthesis of various dispersants of the foregoing types is described in such patents as U.S. Pat. Nos. 2,459,112; 2,962,442, 2,984,550; 3,036,003; 3,163,603; 3,166,516; 3,172,892; 3,184,474; 3,202,678; 3,215,707; 3,216,936; 3,219,666; 3,236,770; 3,254,025; 3,271,310; 3,272,746; 3,275,554; 3,281,357; 3,306,908; 3,311,558; 3,316,177; 3,331,776; 3,340,281; 3,341,542; 3,346,493; 3,351,552; 3,355,270; 3,368,972; 3,381,022; 3,399,141; 3,413,347; 3,415,750; 3,433,744; 3,438,757; 3,442,808; 3,444,170; 3,448,047; 3,448,048; 3,448,049; 3,451,933; 3,454,497; 3,454,555; 3,454,607; 3,459,661; 3,461,172; 3,467,668; 3,493,520; 3,501,405; 3,522,179; 3,539,633; 3,541,012; 3,542,680; 3,543,678; 3,558,743; 3,565,804; 3,567,637; 3,574,101; 3,576,743; 3,586,629; 3,591,598; 3,600,372; 3,630,904; 3,632,510; 3,632,511; 3,634,515; 3,649,229; 3,697,428; 3,697,574; 3,703,536; 3,704,308; 3,725,277; 3,725,441; 3,725,480; 3,726,882; 3,736,357; 3,751,365; 3,756,953; 3,793,202; 3,798,165; 3,798,247; 3,803,039; 3,804,763; 3,836,471; 3,862,981; 3,872,019; 3,904,595; 3,936,480; 3,948,800; 3,950,341; 3,957,746; 3,957,854; 3,957,855; 3,980,569; 3,985,802, 3,991,098; 4,006,089; 4,011,380; 4,025,451; 4,058,468; 4,071,548; 4,083,699; 4,090,854; 4,173,540; 4,234,435; 4,354,950; 4,485,023; 5,137,980, and Re 26,433, herein incorporated by reference.
An example of a suitable dispersant is a borated dispersant. Borated dispersants can be formed by boronating (“borating”) a dispersant having basic nitrogen and/or at least one hydroxyl group in the molecule, such as a succinimide dispersant, succinamide dispersant, succinic ester dispersant, succinic ester-amide dispersant, Mannich base dispersant, or hydrocarbyl amine or polyamine dispersant. Methods that can be used for borating the various types of dispersants described above are described in U.S. Pat. Nos. 3,087,936; 3,254,025; 3,281,428; 3,282,955; 2,284,409; 2,284,410; 3,338,832; 3,344,069; 3,533,945; 3,658,836; 3,703,536; 3,718,663; 4,455,243; and 4,652,387, the disclosures of which are hereby incorporated by reference in their entirety.
The borated dispersant can include a high molecular weight dispersant treated with boron such that the borated dispersant includes up to about 2 wt % of boron, for example from about 0.8 wt % or less of boron, as a further example from about 0.1 to about 0.7 wt % of boron, as an even further example, from about 0.25 to about 0.7 wt % of boron, and as a further example from about 0.35 to about 0.7 wt % of boron. The dispersant can be dissolved in oil of suitable viscosity for ease of handling. It should be understood that the weight percentages given here are for neat dispersant, without any diluent oil added.
A dispersant can be further reacted with an organic acid, an anhydride, and/or an aldehyde/phenol mixture. Such a process can enhance compatibility with elastomer seals, for example. The borated dispersant can further include a mixture of borated dispersants. As a further example, the borated dispersant can include a nitrogen-containing dispersant and/or may be free of phosphorus.
In an aspect, the dispersant for use in the disclosed lubricant composition can be an ethylene-propylene dispersant. In particular, the dispersant can be an ethylene-propylene copolymer grafted with maleic anhydride and reacted with n-phenyl phenylene diamine.
Low molecular weight ethylene-alpha-olefin succinic anhydride dispersants, as described in U.S. Pat. Nos. 5,075,383 and 6,117,825, the disclosures of which are hereby incorporated by reference, are also suitable for use herein. Also suitable in the present disclosure are ethylene alpha-olefin polymers as described in U.S. Pat. Nos. 5,266,223; 5,350,532; and 5,435,926, the disclosures of which are hereby incorporated by reference. Ethylene-propylene diene polymers, such as those described in U.S. Pat. Nos. 4,952,637, 5,356,999, 5,374,364, and 5,424,366, the disclosures of which are hereby incorporated by reference, are also suitable.
A cross-linked low molecular weight ethylene-propylene succinic anhydride dispersant can also be suitable for use in the present invention. These cross-linked dispersants are similar to the low molecular weight ethylene alpha-olefin succinic anhydride dispersants discussed above, but additionally contain a multifunctional polyamine to achieve advantageous cross linking, as described in U.S. Pat. No. 6,107,258, the disclosure of which is hereby incorporated by reference.
Suitable dispersants can be derived from ethylene-alpha-olefin polymers having a molecular weight of ranging from about 300 to about 25,000, for example from about 1000 to about 15,000; and as a further example from about 5,000 to about 15,000.
In an additional aspect, the dispersant can be a highly grafted, amine derivatized functionalized ethylene-propylene copolymer as described fully in U.S. Pat. Nos. 5,139,688 and 6,107,257, the disclosures of which are hereby incorporated by reference.
In an aspect, the dispersant can be a functionalized olefin copolymer. The polymer or copolymer substrate can be prepared from ethylene and propylene or it can be prepared from ethylene and at least one higher olefin within the range of C3 to C23 alpha-olefins.
Non-limiting examples of polymers for use herein include copolymers of ethylene and at least one C3 to C23 alpha-olefins. In an aspect, copolymers of ethylene and propylene can be used. Other alpha-olefins suitable in place of propylene to form the copolymer or to be used in combination with ethylene and propylene to form a terpolymer include 1-butene, 2-butene, isobutene, 1-pentene, 1-hexene, 1-octene and styrene; α,ω-diolefins such as 1,5-hexadiene, 1,6-heptadiene, 1,7-octadiene; branched chain alpha-olefins such as 4-methylbutene-1,5-methylpentene-1, and 6-methylheptene-1; and mixtures thereof.
More complex polymer substrates, often designated as interpolymers, can be prepared using a third component. The third component generally used to prepare an interpolymer substrate can be a polyene monomer selected from non-conjugated dienes and trienes. The non-conjugated diene component can be one having from 5 to 14 carbon atoms in the chain. For example, the diene monomer can be characterized by the presence of a vinyl group in its structure and can include cyclic and bicyclo compounds. Representative dienes include 1,4-hexadiene, 1,4-cyclohexadiene, dicyclopentadiene, 5-ethylidene-2-norbornene, 5-methylene-2-norborene, 1,5-heptadiene, and 1,6-octadiene. A mixture of more than one diene can be used in the preparation of the interpolymer. In an embodiment, a non-conjugated diene for preparing a terpolymer or interpolymer substrate can be 1,4-hexadiene.
The triene component can have at least two non-conjugated double bonds, and up to about 30 carbon atoms in the chain. Typical trienes useful in preparing the interpolymer of the invention can be 1-isopropylidene-3α,4,7,7α.-tetrahydroindene, 1-isopropylidenedicyclopentadiene, dihydro-isodicyclopentadiene, and 2-(2-methylene-4-methyl-3-pentenyl)[2.2.1]bicyclo-5-heptene.
Ethylene-propylene or higher alpha-olefin copolymers can comprise from about 15 to 80 mole percent ethylene and from about 85 to about 20 mole percent C3 to C23 alpha-olefin with, for example, mole ratios from about 35 to about 75 mole percent ethylene and from about 65 to about 25 mole percent of a C3 to C23 alpha-olefin, with for example proportions being from about 50 to about 70 mole percent ethylene and about 50 to about 30 mole percent C3 to C23 alpha-olefin, and as a further example proportions being from about 55 to about 65 mole percent ethylene and about 45 to about 35 mole percent C3 to C23 alpha-olefin.
Terpolymer variations of the foregoing polymers can comprise from about 0.1 to about 10 mole percent of a non-conjugated diene or triene.
The terms polymer and copolymer can be used generically to encompass ethylene copolymers, terpolymers, or interpolymers. These materials can comprise minor amounts of other olefinic monomers so long as the basic characteristics of the ethylene copolymers are not materially changed. One of ordinary skill in the art would understand how to make these functionalized olefin copolymers. For example, U.S. Pat. No. 6,107,257, the disclosure of which is hereby incorporated by reference, discloses methods for making functionalized olefin copolymers.
The dispersant can also be a polyalkyl (meth)acrylate copolymer comprising units derived from: (A) about 12 to about 18 weight percent methyl methacrylate; (B) about 75 to about 85 weight percent of C10-C15 alkyl (meth)acrylate(s); and (C) about 2 to about 5 weight percent of a nitrogen-containing dispersant monomer. The polyalkyl (meth)acrylate copolymers can comprise the reaction products of: (A) from about 12 to about 18 weight percent methyl methacrylate; (B) from about 75 to about 85 weight percent of C10-C15 alkyl (meth)acrylate(s); and (C) from about 2 to about 5 weight percent of a nitrogen-containing dispersant monomer.
As used herein, C10-C15 alkyl (meth)acrylate means an alkyl ester of acrylic or methacrylic acid having a straight or branched alkyl group of about 10 to about 15 carbon atoms per group including, but not limited to, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, lauryl (meth)acrylate, myristyl (meth)acrylate, dodecyl pentadecyl methacrylate, and mixtures thereof.
The alkyl (meth)acrylate comonomers containing about 10 or more carbon atoms in the alkyl group can generally be prepared by standard esterification procedures using technical grades of long chain aliphatic alcohols, and these commercially available alcohols are mixtures of alcohols of varying chain lengths in the alkyl groups. Consequently, for the purposes of this disclosure, alkyl (meth)acrylate is intended to include not only the individual alkyl (meth)acrylate product named, but also to include mixtures of the alkyl (meth)acrylates with a predominant amount of the particular alkyl (meth)acrylate named.
The nitrogen-containing dispersant monomers suitable for use herein include dialkylamino alkyl (meth)acrylamides such as, N,N-dimethylaminopropyl methacrylamide; N,N-diethylaminopropyl methacrylamide; N,N-dimethylaminoethyl acrylamide and N,N-diethylaminoethyl acrylamide; and dialkylaminoalkyl (meth)acrylates such as N,N-dimethylaminoethyl methacrylate; N,N-diethylaminoethyl acrylate and N,N-dimethylaminoethyl thiomethacrylate.
In an aspect, the polyalkyl (meth)acrylate copolymers consist essentially of the reaction products of (A), (B), and (C). However, those skilled in the art will appreciate that minor levels of other monomers, polymerizable with monomers (A), (B), and/or (C) disclosed herein, can be present as long as they do not adversely affect the low temperature properties of the fully formulated fluids. Typically additional monomers can be present in an amount of less than about 5 weight percent, for example in an amount of less than about 3 weight percent, and as a further example in an amount of less than about 1 weight percent. For example, the addition of minor levels of monomers such as C2-C9 alkyl (meth)acrylates, hydroxy- or alkoxy-containing alkyl (meth)acrylates, ethylene, propylene, styrene, vinyl acetate, and the like are contemplated within the scope of this disclosure. In an aspect, the sum of the weight percent of (A), (B), and (C) equals 100%.
The copolymers can be prepared by various polymerization techniques including free-radical and anionic polymerization.
Conventional methods of free-radical polymerization can be used to prepare the copolymers. Polymerization of the acrylic and/or methacrylic monomers can take place under a variety of conditions, including bulk polymerization, solution polymerization, usually in an organic solvent, preferably mineral oil, emulsion polymerization, suspension polymerization, and non-aqueous dispersion techniques.
The dispersant can be present in the lubricant system comprising an engine oil, a transmission fluid, and a gear oil in any desired or effective amount. In an aspect, the engine oil can comprise a dispersant in an amount from about 1% to about 15% by weight, for example from about 1% to about 12%, and as a further example from about 1% to about 10% by weight relative to the total weight of the engine oil. In another aspect, the transmission fluid can comprise a dispersant in an amount from about 1% to about 25% by weight, for example from about 2% to about 20%, and as a further example from about 3% to about 18% by weight relative to the total weight of the transmission fluid. In yet another aspect, the gear oil can comprise a dispersant in an amount from about 0.1% to about 5% by weight, for example from about 0.5% to about 3%, and as a further example from about 1% to about 2% by weight relative to the total weight of the gear oil. However, one of ordinary skill in the art would understand that any amount can be used.
In an aspect, the detergent for use in the disclosed lubricant system can be selected from the group consisting of sulfonates, phenates, sulfurized phenates, carboxylates, salicylates, thiophosphonates, naphthenates of a metal, and combinations thereof.
A suitable detergent can include an oil-soluble neutral or overbased salt of alkali or alkaline earth metal with one or more of the following acidic substances (or mixtures thereof): (1) a sulfonic acid, (2) a carboxylic acid, (3) a salicylic acid, (4) an alkyl phenol, (5) a sulfurized alkyl phenol, and (6) an organic phosphorus acid characterized by at least one direct carbon-to-phosphorus linkage. Such an organic phosphorus acid can include those prepared by the treatment of an olefin polymer (e.g., polyisobutylene having a molecular weight of about 1,000) with a phosphorizing agent such as phosphorus trichloride, phosphorus heptasulfide, phosphorus pentasulfide, phosphorus trichloride and sulfur, white phosphorus and a sulfur halide, or phosphorothioic chloride.
The term “overbased” in connection with metallic detergents is used to designate metal salts wherein the metal is present in stoichiometrically larger amounts than the organic radical. The commonly employed methods for preparing the overbased salts involve heating a mineral oil solution of an acid with a stoichiometric excess of a metal neutralizing agent such as the metal oxide, hydroxide, carbonate, bicarbonate, or sulfide at a temperature of about 50° C., and filtering the resultant product. The use of a “promoter” in the neutralization step to aid the incorporation of a large excess of metal likewise is known. Examples of compounds useful as the promoter include phenolic substances such as phenol, naphthol, alkyl phenol, thiophenol, sulfurized alkylphenol, and condensation products of formaldehyde with a phenolic substance; alcohols such as methanol, 2-propanol, octanol, 2-ethoxyethanol, diethylene glycol ethyl ether, ethylene glycol, stearyl alcohol, and cyclohexyl alcohol; and amines such as aniline, phenylene diamine, phenothiazine, phenyl-beta-naphthylamine, and dodecylamine. A particularly effective method for preparing the basic salts comprises mixing an acid with an excess of a basic alkaline earth metal neutralizing agent and at least one alcohol promoter, and carbonating the mixture at an elevated temperature such as about 60° C. to about 200° C.
Examples of suitable metal-containing detergents include, but are not limited to, neutral and overbased salts of such substances as neutral sodium sulfonate, an overbased sodium sulfonate, a sodium carboxylate, a sodium salicylate, a sodium phenate, a sulfurized sodium phenate, a lithium sulfonate, a lithium carboxylate, a lithium salicylate, a lithium phenate, a sulfurized lithium phenate, a calcium sulfonate, a calcium carboxylate, a calcium salicylate, a calcium phenate, a sulfurized calcium phenate, a magnesium sulfonate, a magnesium carboxylate, a magnesium salicylate, a magnesium phenate, a sulfurized magnesium phenate, a potassium sulfonate, a potassium carboxylate, a potassium salicylate, a potassium phenate, a sulfurized potassium phenate, a zinc sulfonate, a zinc carboxylate, a zinc salicylate, a zinc phenate, and a sulfurized zinc phenate. Further examples include a calcium, lithium, sodium, potassium, and magnesium salt of a hydrolyzed phosphosulfurized olefin having about 10 to about 2,000 carbon atoms or of a hydrolyzed phosphosulfurized alcohol and/or an aliphatic-substituted phenolic compound having about 10 to about 2,000 carbon atoms. Even further examples include a calcium, lithium, sodium, potassium, and magnesium salt of an aliphatic carboxylic acid and an aliphatic substituted cycloaliphatic carboxylic acid and many other similar alkali and alkaline earth metal salts of oil-soluble organic acids. A mixture of a neutral or an overbased salt of two or more different alkali and/or alkaline earth metals can be used, Likewise, a neutral and/or an overbased salt of mixtures of two or more different acids can also be used.
As is well known, overbased metal detergents are generally regarded as containing overbasing quantities of inorganic bases, generally in the form of micro dispersions or colloidal suspensions. Thus the term “oil-soluble” as applied to metallic detergents is intended to include metal detergents wherein inorganic bases are present that are not necessarily completely or truly oil-soluble in the strict sense of the term, inasmuch as such detergents when mixed into base oils behave much the same way as if they were fully and totally dissolved in the oil. Collectively, the various metallic detergents referred to herein above, are sometimes called neutral, basic, or overbased alkali metal or alkaline earth metal-containing organic acid salts.
Methods for the production of oil-soluble neutral and overbased metallic detergents and alkaline earth metal-containing detergents are well known to those skilled in the art, and extensively reported in the patent literature. See, for example, U.S. Pat. Nos. 2,001,108; 2,081,075; 2,095,538; 2,144,078; 2,163,622; 2,270,183; 2,292,205; 2,335,017; 2,399,877; 2,416,281; 2,451,345; 2,451,346; 2,485,861; 2,501,731; 2,501,732; 2,585,520; 2,671,758; 2,616,904; 2,616,905; 2,616,906; 2,616,911; 2,616,924; 2,616,925; 2,617,049; 2,695,910; 3,178,368; 3,367,867; 3,496,105; 3,629,109; 3,865,737; 3,907,691; 4,100,085; 4,129,589; 4,137,184; 4,184,740; 4,212,752; 4,617,135; 4,647,387; and 4,880,550, the disclosures of which are hereby incorporated by reference in their entirety.
The metallic detergents utilized in this invention can, if desired, be oil-soluble boronated neutral and/or overbased alkali or alkaline earth metal-containing detergents. Methods for preparing boronated metallic detergents are described in, for example, U.S. Pat. Nos. 3,480,548; 3,679,584; 3,829,381; 3,909,691; 4,965,003; and 4,965,004, the disclosures of which are hereby incorporated by reference.
The detergent can be present in the lubricant system comprising an engine oil, a transmission fluid, and a gear oil in any desired or effective amount. In an aspect, the engine oil can comprise a detergent in an amount from about 0.01% to about 5% by weight, for example from about 0.05% to about 4% by weight, and as a further example from about 0.1% to about 3% by weight relative to the total weight of the engine oil. A detergent can also be present in the transmission fluid and/or the gear oil. One of ordinary skill in the art would understand that any amount can be used in the transmission fluid and/or the gear oil.
In an aspect, the antioxidant for use in the disclosed lubricant system can be selected from the group consisting of phenolic antioxidants, hindered phenolic antioxidants, additional sulfurized olefins, aromatic amine antioxidants, secondary aromatic amine antioxidants, sulfurized phenolic antioxidants, oil-soluble copper compounds, and mixtures thereof Suitable exemplary compounds include but are not limited to 2,6-di-tert-butylphenol, liquid mixtures of tertiary butylated phenols, 2,6-di-tert-butyl-4-methylphenol, 4,4′-methylenebis(2,6-di-tert-butylphenol), 2,2′-methylenebis(4-methyl-6-tert-butylphenol), mixed methylene-bridged polyalkyl phenols, 4,4′-thiobis(2-methyl-6-tert-butylphenol), N,N′-di-sec-butyl-p-phenylenediamine, 4-isopropylaminodiphenyl amine, alkylated diphenylamine and phenyl-α-naphthyl amine.
In the class of amine antioxidants, oil-soluble aromatic secondary amines, aromatic secondary monoamines, and others can be used. Suitable aromatic secondary monoamines include diphenylamine, alkyl diphenylamines containing 1 to 2 alkyl substituents each having up to about 16 carbon atoms, phenyl-α-naphthylamine, alkyl- or aralkylsubstituted phenyl-α-naphthylamine containing one or two alkyl or aralkyl groups each having up to about 16 carbon atoms, alkyl- or aralkyl-substituted phenyl-α-naphthylamine containing one or two alkyl or aralkyl groups each having up to about 16 carbon atoms, alkylated ρ-phenylene diamines, and similar compounds.
In the class of phenolic antioxidants, suitable exemplary compounds include ortho-alkylated phenolic compounds, e.g. 2-tert-butylphenol, 2,6-di-tertbutylphenol, 4-methyl-2,6-di-tertbutylphenol, 2,4,6-tri-tertbutylphenol, and various analogs and homologs or mixtures thereof; one or more partially sulfurized phenolic compounds as described in U.S. Pat. No. 6,096,695, the disclosure of which is incorporated herein by reference; methylene-bridged alkylphenols as described in U.S. Pat. No. 3,211,652, the disclosure of which is incorporated herein by reference.
The antioxidant can be present in the lubricant system comprising an engine oil, a transmission fluid, and a gear oil in any desired or effective amount. In an aspect, the engine oil can comprise an antioxidant in an amount from about 0.3% to about 5% by weight, for example from about 0.5% to about 3.5% by weight, and as a further example from about 0.7% to about 2% by weight relative to the total weight of the engine oil. An antioxidant can also be present in the transmission fluid and/or the gear oil. One of ordinary skill in the art would understand that any amount can be used in the transmission fluid and/or the gear oil.
In an aspect, the lubricant system can comprise various lubrication compositions, such as an engine oil, a transmission fluid, and a gear oil. In an aspect, the lubricant system is understood to encompass all of the compositions that provide lubricating properties and can be provided to a machine, such as a vehicle. These lubricant compositions can each individually also comprise an antiwear compound. The antiwear compound can comprise zinc salts of dithioorganophosphates. The antiwear compound can be present in the lubrication compositions in any desired or effective amount. In an aspect, the engine oil can comprise an antiwear compound in an amount from about 0.5% to about 10% by weight, for example from about 1% to about 8%, and as a further example from about 1.5% to about 7.5% by weight relative to the total weight of the engine oil composition. An antiwear compound can also be present in the transmission fluid and/or the gear oil. One of ordinary skill in the art would understand that any amount can be used in the transmission fluid and/or the gear oil
In another aspect, the lubricant system comprising an engine oil, a transmission fluid, and a gear oil can comprise a pour-point depressant. The pour point depressant can comprise at least one of polymethacrylates; polyacrylates; condensation products of haloparaffin waxes and aromatic compounds; vinyl carboxylate polymers; and terpolymers of dialkylfumarates, vinyl esters of fatty acids, alkyl vinyl ethers, and mixtures thereof; ethylene-vinyl acetate copolymers, and alkyl phenol formaldehyde condensation resins. Techniques for preparing such polymers and their uses are disclosed in U.S. Pat. Nos. 2,387,501; 2,015,748; 2,655,479, 1,815,022; 2,191,498; 2,666,746; 2,721,877; 2,721,878; 3,250,715; 6,645,920; and 6,872,693, which are herein incorporated by reference for their relevant disclosures.
The pour-point depressant can be present in the lubricant system comprising an engine oil, a transmission fluid, and a gear oil in any desired or effective amount. In an aspect, the transmission fluid can comprise a pour point depressant in an amount from about 0.001% to about 1.5% by weight, for example from about 0.05% to about 1.2% by weight, and as a further example from about 0.1% to about 1% by weight relative to the total weight of the transmission fluid. A pour-point depressant can also be present in the engine oil and/or the gear oil. One of ordinary skill in the art would understand that any amount can be used in the engine oil and/or the gear oil.
In an aspect, the lubricant system comprising an engine oil, a transmission fluid, and a gear oil can comprise a viscosity index improver. The viscosity index improver can be selected from the group consisting of olefin (co) polymer(s), polyalkyl (meth) acrylate(s), vinyl aromatic-diene copolymers, and mixtures thereof,
The viscosity index improver can be present in the lubricant system comprising an engine oil, a transmission fluid, and a gear oil in any desired or effective amount. In an aspect, the engine oil can comprise a viscosity index improver in an amount from about 0.001% to about 30% by weight, for example from about 0.1% to about 25% by weight, and as a further example from about 0.5% to about 20% by weight relative to the total weight of the engine oil. In another aspect, the gear oil can comprise a viscosity index improver in an amount from about 0.001% to about 30% by weight, for example from about 0.01% to about 25% by weight, and as a further example from about 0.1% to about 20% by weight relative to the total weight of the gear oil. A viscosity index improver can also be present in the transmission fluid. One of ordinary skill in the art would understand that any amount can be used in the transmission fluid.
In an aspect, the lubricant system comprising an engine oil, a transmission fluid, and a gear oil can comprise an extreme pressure agent. The extreme pressure agent can comprise at least one of sulfur-containing additives, esters of boron acids, esters of phosphorus acids, amine salts of phosphorus acids and acid esters, higher carboxylic acids, and chlorine-containing additives. One of ordinary skill in the art would know that the extreme pressure agent can also comprise derivatives of higher carboxylic acids. In another aspect, the sulfur-containing additives can comprise a sulfur-organic compound comprising a sulfur-containing species bound directly to carbon or to more sulfur.
Typical sulfur-containing, extreme pressure agents and/or antiwear compounds comprise dihydrocarbyl polysulfides; sulfurized olefins; sulfurized fatty acid esters of both natural (e.g. sperm oil) and synthetic origins; trithiones; thienyl derivatives; sulfurized terpenes; sulfurized oligomers of C2-C8 monoolefins; xanthates of alkanols and other organo-hydroxy compounds such as phenols; thiocarbamates made from alkyl amines and other organo amines; and sulfurized Diels-Alder adducts such as those disclosed in U.S. Pat. No, Re. 27,331, the disclosure of which is hereby incorporated by reference. Specific examples include sulfurized polyisobutene of Mn 1,100, sulfurized isobutylene, sulfurized triisobutene, dicyclohexyl disulfide, diphenyl and dibenzyl disulfide, di-tert-butyl trisulfide, and dinonyl trisulfide, among others.
Esters of boron acids comprising borate, metaborate, pyroborate and biborate esters of monohydric and/or polyhydric alcohols and/or phenols, such as trioctyl borate, tridecyl borate, 2-ethylhexyl pyroborate, isoamyl metaborate, trixylyl borate, (butyl)(2,4-hexanediyl)borate, and the like can also be used as an extreme pressure agent.
Typical esters of phosphorus acids which may be used as extreme pressure agents and/or antiwear agent comprise trihydrocarbyl phosphites, phosphonates and phosphates, and dihydrocarbyl phosphites; such as tricresyl phosphate, tributyl phosphite, tris(2-chloroethyl)phosphate and phosphite, dibutyl trichloromethyl phosphonates, di(n-butyl)phosphite, triphenyl phosphite, and tolyl phosphinic acid dipropyl ester.
Among the amine salts of phosphorus acids and phosphorus acid-esters which can be employed are amine salts of partially esterified phosphoric, phosphorous, phosphonic, and phosphinic acids and their partial or total thio analogs such as partially esterified monothiophosphoric, dithiophosphoric, trithiophosphoric, and tetrathiophosphoric acids; amine salts of phosphonic acids and their thio analogs; and the like. Specific examples include the dihexylammonium salt of dodecylphosphoric acid, the diethyl hexyl ammonium salt of dioctyl dithiophosphoric acid, the octadecylammonium salt of dibutyl thiophosphoric acid, the dilaurylammonium salt of 2-ethylhexylphosphoric acid, the dioleyl ammonium salt of butane phosphonic acid, and analogous compounds.
Higher carboxylic acids and derivatives which can be used as extreme pressure agents and/or antiwear can be illustrated by fatty acids, dimerized and trimerized unsaturated natural acids (e.g., linoleic) and esters, amine, ammonia, and metal (particularly lead) salts thereof and amides and imidazoline salt and condensation products thereof oxazolines, and esters of fatty acids, such as ammonium di-(linoleic) acid, lard oil, oleic acid, animal glycerides, lead stearate, etc.
Suitable chlorine-containing additives include, but are not limited to, chlorinated waxes of both the paraffinic and microcrystalline type, polyhaloaromatics such as di- and trichlorobenzene, trifluoromethyl naphthalenes, perchlorobenzene, pentachlorophenol, and dichloro diphenyl trichloroethane. Also useful are chlorosulfurized olefins and olefinic waxes and sulfurized chlorophenyl methyl chlorides and chloroxanthates. Specific examples include chlorodibenzyl disulfide, chlorosulfurized polyisobutene of Mn 600, chlorosulfurized pinene and chlorosulfurized lard oil.
The extreme pressure agent can be present in the lubricant system comprising an engine oil, a transmission fluid, and a gear oil in any desired or effective amount. In an aspect, the gear oil can comprise an extreme pressure agent in an amount from about 0.01% to about 10% by weight, for example from about 0.05% to about 8% by weight, and as a further example from about 0.1% to about 5% by weight relative to the total weight of the gear oil. An extreme pressure agent can also be present in the engine oil and/or the transmission fluid. One of ordinary skill in the art would understand that any amount can be used in the engine oil and/or the transmission fluid.
In an aspect, the engine oil of the lubricant system can further comprise at least one of friction modifiers, anti-foamers, diluents, and pour-point depressants. In another aspect, the transmission fluid of the lubricant system can further comprise at least one of detergents, antiwear compounds, antioxidants, friction modifiers, anti-foamers, and diluents. In yet another aspect, the gear oil of the lubricant system can further comprise at least one of detergents, demulsifiers, antioxidants, friction modifiers, anti-foamers, diluents, and phosphorus-containing compounds. One of ordinary skill in the art would know that one or more of dispersants, detergents, demulsifiers, friction modifiers, extreme pressure agents, antiwear compounds, antioxidants, anti-foamers, diluents, pour-point depressants, diluents, viscosity index improvers, corrosion inhibitors, phosphorus-containing compounds can be present in the engine oil, the transmission fluid, and/or the gear oil of the lubricant system.
One of ordinary skill in the art would know that the engine oil can be blended to a lower viscosity grade, such as from SAE 15W-40 to SAE 10W-30, or even to SAE 5W-30. In order to make such a change, one could adjust the base oil blend viscosity, which could thereby change the viscosity index improver dosage. Exemplary base oil blend viscosities include, but are not limited to about 5.5 cSt to about 9 cSt for the SAE 15W-40 grade engine oil, about 5 cSt to about 8 cSt for the SAE 10W-30 grade engine oil, and about 4 cSt to about 6 cSt for the SAE 5W-30 grade engine oil. The dosages for the viscosity index improver can also be adjusted accordingly, such as, for example, the SAE 15W-40 grade engine oil can comprise a viscosity index improver in an amount from about 6.5% to about 10% by weight; the SAE 10W-30 grade engine oil can comprise a viscosity index improver in an amount from about 5% to about 8% by weight; and the SAE 5W-30 grade engine oil can comprise a viscosity index improver in an amount from about 6% to about 10% by weight.
In some embodiments, the disclosed lubricant system can comprise an engine lubricated with the engine oil, a transmission lubricated with the transmission fluid, and a gear set lubricated with the gear oil. In another embodiment, a class 8 over-the-road diesel truck can comprise the disclosed lubricant system. In a further embodiment, the transmission fluid of the disclosed lubricant system can be chosen from an automatic transmission fluid, a manual transmission fluid, a dual clutch transmission fluid, and a continuously variable transmission fluid.
In an aspect, there is a method of improving fuel economy of a vehicle comprising providing to the vehicle a lubricant system comprising an engine oil comprising at least one additive chosen from a viscosity index improver, a dispersant, a detergent, an antioxidant, and an antiwear compound; a transmission fluid comprising at least one additive chosen from a dispersant and a pour-point depressant; and a gear oil comprising at least one additive chosen from a viscosity index improver, an extreme pressure agent, and a dispersant.
In another aspect, there is a multi-component kit comprising a first component comprising an engine oil comprising at least one additive chosen from a viscosity index improver, a dispersant, a detergent, an antioxidant, and an antiwear compound; a second component comprising a transmission fluid comprising at least one additive chosen from a dispersant and a pour-point depressant; and a third component comprising a gear oil comprising at least one additive chosen from a viscosity index improver, an extreme pressure agent, and a dispersant.
A truck fleet A comprising 8 trucks, wherein each truck comprises Detroit Diesel engines, Eaton transmissions, and Meritor or Alliance axles can run on the disclosed lubricant system comprising an engine oil, a transmission fluid, and a gear oil. An exemplary disclosed lubricant system is shown in Table 1. A truck fleet B comprising 8 trucks, wherein each truck comprises Detroit Diesel engines, Eaton transmissions, and Meritor or Alliance axles can run on a commercially available engine oil, manual transmission fluid, and gear oil. The truck fleets A and B can be class 8 over-the-road diesel trucks, and in general freight hauler use. Furthermore, all the trucks could have about 100,000 miles before the beginning of the proposed test and could have no more than about 250,000 miles of service at the end of the proposed test.
It is hypothesized that a truck fleet comprising the disclosed lubricant system, such as proposed Truck Fleet A, could exhibit an improved fuel economy of about 2.5% to about 5% over about 100,000 miles of service as compared to a truck fleet devoid of the disclosed lubricant system, such as proposed truck fleet B.
At numerous places throughout this specification, reference has been made to a number of U.S. patents, published foreign patent applications and published technical papers. All such cited documents are expressly incorporated in full into this disclosure as if fully set forth herein.
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.
Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the disclosure are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Moreover, all ranges disclosed herein are to be understood to encompass any and all sub-ranges subsumed therein. For example, a range of “less than 10” can include any and all sub-ranges between (and including) the minimum value of zero and the maximum value of 10, that is, any and all sub-ranges having a minimum value of equal to or greater than zero and a maximum value of equal to or less than 10, e.g., 1 to 5.
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 one 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.
This invention is susceptible to considerable variation in its practice. Therefore the foregoing description is not intended to limit, and should not be construed as limiting, the invention to the particular exemplifications presented hereinabove. Rather, what is intended to be covered is as set forth in the ensuing claims and the equivalents thereof permitted as a matter of law.
Applicant does not intend to dedicate any disclosed embodiments to the public, and to the extent any disclosed modifications or alterations may not literally fall within the scope of the claims, they are considered to be part of the invention under the doctrine of equivalents.
