Patent Application
20050261142
The present invention relates to a composition containing a polymeric dispersant viscosity modifier; and an amine salt of a phosphorus compound. The invention further provides a process for making the composition and a method for lubricating a gear or bearing surface with the composition.
Oxidation of an oil of lubricating viscosity, especially an organic petroleum fluid, occurs in the presence of oxygen which leads to increased viscosity and sludge and/or deposit formation. Sludge and/or deposit formation is produced by a number of different mechanisms such as degradation of oil and decomposition products of lubricant additives. Using known lubricant additives containing an amine salt of a phosphorus compound such as many antiwear agents and friction modifiers are believed to contribute to the formation of sludge and/or deposit formation. The presence of sludge and other deposits interferes with seal performance leading to leakage and ultimately equipment failure for gears or bearings.
Polymeric dispersant viscosity modifier are added to lubricating compositions to impart resistance to rust, improved cleanliness, improved viscosity modifying properties and decreased sludge accumulation. The polymeric dispersant viscosity modifier is generally a nitrogen containing poly(meth)acrylate, a nitrogen containing polyolefin or a nitrogen containing esterified styrene-maleic anhydride interpolymer.
U.S. Pat. No. 6,124,249 (Seebauer et al.) discloses a dispersant viscosity improving copolymer derived from (a) a nitrogen containing monomer; and (b) methacrylic acid esters containing from about 9 to about 25 carbon atoms in the ester group.
U.S. Pat. No. 6,586,375 (Gahagan et al.) discloses a lubricant composition containing a nitrogen containing polyacrylate salted with a phosphorus acid ester. The lubricant composition provides improved dispersant, viscosity improver and antiwear properties.
It is desirable to have a composition capable of decreasing sludge accumulation. The present invention provides a composition capable of decreasing sludge accumulation.
It is desirable to have a composition with deposit control. The present invention provides a composition with deposit control.
The present invention is a composition comprising:
The invention further provides a method comprising lubricating a surface while imparting deposit control, the method employing a composition comprising:
The invention further provides a process for the preparation of a composition comprising mixing:
The use of the composition of the invention is capable of imparting one or more performance characteristics including deposit control, reduced carbon varnish, decreased wear, low temperature viscometrics, high temperature viscometrics or mixtures thereof.
A composition comprising:
The lubricating oil composition includes natural or synthetic oils of lubricating viscosity, oil derived from hydrocracking, hydrogenation, hydrofinishing, unrefined, refined and re-refined oils or mixtures thereof. Natural oils include animal oils, vegetable oils, mineral oils or mixtures thereof. Synthetic oils include a hydrocarbon oil, a silicon-based oil, a liquid esters of phosphorus-containing acid. Synthetic oils may be produced by Fischer-Tropsch reactions and typically may be hydroisomerised Fischer-Tropsch hydrocarbons or waxes Oils of lubricating viscosity may also be defined as specified in the American Petroleum Institute (API) Base Oil Interchangeability Guidelines. In one embodiment the oil of lubricating viscosity comprises an API Group I, II, III, IV, V, VI or mixtures thereof, and in one embodiment API Group I, II, III or mixtures thereof. If the oil of lubricating viscosity is an API Group II, III, IV, V or VI oil there may be up to about 40 wt % and in another embodiment up to a maximum of about 5 wt % of the lubricating oil an API Group I oil.
The oil of lubricating viscosity is present at up to about 99.9 wt % of the composition, in another embodiment up to about 98.9 wt % of the composition, in another embodiment up to about 96.8 wt % of the composition and in yet another embodiment up to about 94.8 wt % of the composition. In one embodiment of the invention the oil of lubricating viscosity is present from about 30 wt % to about 99.9 wt % of the composition, in another embodiment about 45 wt % to about 94.8 wt % and in another embodiment about 60 wt % to about 90 wt % of the composition.
In one embodiment the invention is in the form of a concentrate (which can be combined with additional oil to form, in whole or in part, a finished lubricant), the ratio of each of the above-mentioned polymeric dispersant viscosity modifier and an amine salt of a phosphorus compound, as well as other components, to diluent oil in the range from about 80:20 to about 10:90 by weight.
Amine Salt of Phosphorus Compound
The invention further includes an amine salt of a phosphorus compound. The amine salt of a phosphorus compound includes an extreme pressure agent, a wear preventing agent, a friction modifier or mixtures thereof. In one embodiment of the invention the amine salt of a phosphorus compound further comprises a sulphur atom in the molecule. In one embodiment of the invention the amine salt of a phosphorus compound is ashless i.e. metal-free.
The amine includes a primary amine, a secondary amine, a tertiary amine or mixtures thereof. The amine includes those with at least one hydrocarbyl group, in another embodiment about two hydrocarbyl groups and in another embodiment about three hydrocarbyl groups. The hydrocarbyl group contains a number of carbon atoms including those in the range from about 2 to about 30, in another embodiment about 8 to about 26, in another embodiment about 10 to about 20, and in yet another embodiment about 13 to about 19.
Primary amines include ethylamine, propylamine, butylamine, 2-ethylhexylamine, octylamine and dodecylamine. Also suitable primary fatty amines which include n-octylamine, n-decylamine, n-dodecylamine, n-tetradecylamine, n-hexadecylamine, n-octadecylamine and oleyamine. Other useful fatty amines include commercially available fatty amines such as “Armeen®” amines (products available from Akzo Chemicals, Chicago, Ill.), such as Armeen C, Armeen O, Armeen O L, Armeen T, Armeen H T, Armeen S and Armeen S D, wherein the letter designation relates to the fatty group, such as coco, oleyl, tallow, or stearyl groups.
Examples of suitable secondary amines include dimethylamine, diethylamine, dipropylamine, dibutylamine, diamylamine, dihexylamine, diheptylamine, methylethylamine, ethylbutylamine and ethylamylamine. The secondary amines may be cyclic amines such as piperidine, piperazine and morpholine.
The amine may also be a tertiary-aliphatic primary amine. The aliphatic group includes an alkyl group containing a number of carbon atoms from 2 to 30, in another embodiment 6 to 26 and in another embodiment 8 to 24. The tertiary alkyl amines include a monoamine such as tert-butylamine, terthexylamine, 1-methyl-1-amino-cyclohexane, tert-octylamine, tert-decylamine, tertdodecylamine, tert-tetradecylamine, tert-hexadecylamine, tert-octadecylamine, terttetracosanylamine, or tert-octacosanylamine.
The amine salt of a phosphorus compound also includes phosphoric acid esters or salt thereof; dialkyldithiophosphoric acid esters or salt thereof; phosphites; and phosphorus-containing carboxylic esters, ethers, and amides or mixtures thereof.
Mixtures of amines may also be used in the invention. In one embodiment a useful mixture of amines is “Primene® 81R” and “Primene® JMT.” Primene® 81R and Primene® JMT (both produced and sold by Rohm & Haas) are mixtures of C11 to C14 tertiary alkyl primary amines and C18 to C22 tertiary alkyl primary amines respectively.
In one embodiment of the invention the amine salt of a phosphorus compound is a friction modifier. Examples of a suitable friction modifier include amine salts of alkylphosphoric acids other than the wear preventing agent.
The amine salt of a phosphorus compound is present in one embodiment in range from about 0 wt % to about 30 wt % of the composition, in another embodiment from about 0.001 wt % to 30 wt % of the composition, in another embodiment from about 0.1 wt % to about 20 wt % of the composition, in another embodiment from about 0.5 wt % to about 15 wt % of the composition and in another embodiment from about 1 wt % to about 10 wt % of the composition.
Polymeric Dispersant Viscosity Modifier
As used hereinafter the term “(meth)acrylate” is used to refer to a methacrylate and a acrylate; and “(meth)acrylamide” is used to refer to a acrylamide and a methacrylamide.
The polymeric dispersant viscosity modifier includes a (co)polymer with a nitrogen containing monomer, a nitrogen containing compound capable of reacting with a functionalised polymer backbone or mixtures thereof. The polymeric dispersant viscosity modifier includes those derived from at least one polymer including a poly(meth)acrylate copolymer, a functionalised polyolefin, an esterified polymer derived from: (i) a vinyl aromatic monomer; and (ii) an unsaturated carboxylic acid or derivatives thereof; or mixtures thereof.
The nitrogen containing monomer includes a vinyl substituted nitrogen heterocyclic monomer, a dialkylaminoalkyl (meth)acrylate monomer, a dialkylaminoalkyl (meth)acrylamide monomer, a tertiary-(meth)acrylamide monomer and mixtures thereof. The alkyl contains 1 to about 8, or from 1 to about 3 carbon atoms.
Useful nitrogen containing monomers include vinyl pyridine, N-vinyl imidazole, N-vinyl pyrrolidinone, and N-vinyl caprolactam, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, dimethylaminobutylacrylamide dimethylamine propyl methacrylate, dimethylaminopropylacrylamide, dimethylaminopropylmethacrylamide, dimethylaminoethylacrylamide, tertiary butyl acrylamide or mixtures thereof.
The nitrogen containing compound includes an amine such as a monoamine, a polyamine or mixtures thereof. The amine includes primary functionality, secondary functionality or mixtures thereof. The amine includes cyclic, linear or branched and examples include an alkylenemonoamine, a heterocyclic monoamine, an alkylenepolyamine, a heterocyclic polyamine or mixtures thereof. In one embodiment the amine contains not more than one primary or secondary amino group, for example N,N-dimethylaminopropylamine.
In one embodiment the amine may be a hydroxy-substituted hydrocarbyl amine such as a hydroxyalkyl amine. Examples of a suitable hydroxy-substituted hydrocarbyl amine include aminoethyl ethanolamine, aminopropyl ethanolamine, aminobutyl ethanolamine or mixtures thereof. In one embodiment the amine includes compounds that are represented by the formula:
wherein
When R3 or R4 is a hydrocarbyl group, the number of carbon atoms present is in the range from 1 to about 8, in another embodiment in the range from 1 to about 5 and in another embodiment in the range from 1 to about 3. Examples of a hydrocarbyl group include methyl, ethyl, propyl, butyl, pentyl or mixtures thereof.
Formula (I) represents a compound that includes a mononuclear cyclic structure, a polynuclear cyclic structure or mixtures thereof. When formula (I) represents a mononuclear structure, w in one embodiment ranges from about 5 to about 8 and in another embodiment about 6 to about 7. When formula (I) represents a polynuclear cyclic structure w in one embodiment ranges from about 8 to about 16 and in another embodiment about 10 to about 12. The cyclic ring includes aromatic, non-aromatic or mixtures thereof, although a non-aromatic ring is especially useful.
Suitable cyclic amines include 4-aminodiphenylamine, 4-(3-aminopropyl) morpholine, 4-(2-aminoethyl) morpholine or mixtures thereof. In one embodiment the cyclic amine is 4-(3-aminopropyl) morpholine or mixtures thereof.
The polymeric dispersant viscosity modifier is also derived from at least one polymer including a poly(meth)acrylate, a functionalised polyolefin, an esterified polymer derived from: (i) a vinyl aromatic monomer; and (ii) an unsaturated carboxylic acid or derivatives thereof; or mixtures thereof. In one embodiment the poly(meth)acrylate further contains a nitrogen containing monomer.
The poly(meth)acrylate polymeric dispersant viscosity modifier includes a copolymer derived from a (meth)acrylate monomer containing an alkyl group with 1 to 30 carbon atoms, in another embodiment 1 to 26 carbon atoms and in another embodiment 1 to 20 carbon atoms. The alkyl group includes mixtures derived from an alcohol containing 1 to about 4 carbon atoms, about 8 to about 10 carbon atoms, about 12 to about 14 carbon atoms, about 12 to about 15 carbon atoms, about 16 to about 18 carbon atoms or about 16 to about 20 carbon atoms. Examples of commercially available alcohol mixtures include the following products sold under the brand names of Dobanol™ 25, Neodol™ 25, Lial™ 125, and Alchem™ 125. In one embodiment the alcohol is a single alcohol i.e. not a mixture.
The (meth)acrylate monomer includes those derived from natural or synthetic sources. When derived by synthetic sources the (meth)acrylate monomer may be prepared using known direct esterification and/or transesterification processes.
In one embodiment the poly(meth)acrylate polymeric dispersant viscosity modifier is derived from a methyl (meth)acrylate monomer and at least one other (meth)acrylate monomer including an alkyl group with about 8 to about 20 carbon atoms, in another embodiment about 10 to about 18 carbon atoms and in another embodiment about 12 to about 15 carbon atoms. The methyl (meth)acrylate monomer is in the range from about 1 wt % or more of the poly(meth)acrylate, in another embodiment in the range from about 8 wt % or more of the poly(meth)acrylate and in another embodiment in the range from about 10 wt % or more of the poly(meth)acrylate. Upper limits on the amount of methyl (meth)acrylate include about 40 wt % of the poly(meth)acrylate, in another embodiment about 30 wt % of the poly(meth)acrylate and in another embodiment about 20 wt % of the poly(meth)acrylate.
In one embodiment the composition containing the polymeric dispersant viscosity modifier excludes copolymers derived from (a) a nitrogen containing monomer; and (b) methacrylic acid esters containing from about 9 to about 25 carbon atoms in the ester group. In another embodiment the composition containing the polymeric dispersant viscosity modifier further excludes a salt of a phosphorus acid ester and a nitrogen containing polyacrylate.
As described hereinafter the molecular weight of the polymeric dispersant viscosity modifier has been determined using known methods, such as GPC analysis using a polystyrene standard.
The poly(meth)acrylate has a molecular weight (Mw) including from about 5000 to about 350,000, in another embodiment about 10,000 to about 150,000, in another embodiment about 15,000 to about 120,000, in another embodiment about 10,000 to about 50,000 and in yet another embodiment about 15,000 to about 35,000.
The polymeric dispersant viscosity modifier derived from a functionalised polyolefin and/or an esterified polymer contain an unsaturated carboxylic acid or derivatives thereof. The carboxylic acid or derivatives thereof includes a mono-acid, a di-acid or mixtures thereof. Optionally the unsaturated carboxylic acid or derivatives thereof is further substituted with a hydrocarbyl group. The hydrocarbyl group includes substituted, unsubstituted, branched, unbranched or mixtures thereof, although, unsubstituted is especially useful.
The unsaturated carboxylic acid anhydride or derivatives thereof may be wholly esterified, partially esterified or mixtures thereof. When partially esterified other derivatives include acids, salts or mixtures thereof. Suitable salts include alkali metals, alkaline earth metals or mixtures thereof. The salts include lithium, sodium, potassium, magnesium, calcium or mixtures thereof.
The unsaturated carboxylic acid or derivatives thereof includes an acrylic acid, a methyl acrylate, a methacrylic acid, a maleic acid or anhydride, a fumaric acid, an itaconic acid or anhydride or mixtures thereof.
Suitable examples of the unsaturated dicarboxylic acid anhydride or derivatives include itaconic anhydride, maleic anhydride, methyl maleic anhydride, ethyl maleic anhydride, dimethyl maleic anhydride or mixtures thereof. The unsaturated carboxylic acid anhydride or derivatives thereof functionality may be used alone or in combination.
In one embodiment the polymeric dispersant viscosity modifier is a functionalised polyolefin. In one embodiment the functionalised polyolefin further contains a nitrogen derived from a nitrogen containing compound capable of reacting with a functionalised polymer backbone.
In one embodiment the functionalised polyolefin is derived from an ethylene monomer and at least one other comonomer derived from an alpha-olefin having the formula H2C═CHR5, wherein R5 is a hydrocarbyl group, especially an alkyl radical containing 1 to about 18 carbon atoms, in another embodiment 1 to about 10 carbon atoms, in another embodiment 1 to about 6 carbon atoms and in yet another embodiment 1 to about 3 carbon atoms. The hydrocarbyl group includes an alkyl radical that has a straight chain, a branched chain or mixtures thereof. Examples of a comonomer include propylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene, 1-decene or mixtures thereof. In one embodiment the comonomer includes 1-butene, propylene or mixtures thereof. Examples of the olefin copolymers include ethylene-propylene copolymers, ethylene-1-butene copolymers or mixtures thereof.
In another embodiment the alpha-olefin includes a comonomer with about 6 to about 40 carbon atoms, in another embodiment about 10 to about 34 carbon atoms, and in another embodiment about 14 to about 22 carbon atoms. Examples of an alpha-olefin include 1-decene 1-undecene, 1-dodecene, 1-tridecene, 1-butadecene, 1-pentadecene, 1-hexadecene, 1-heptadecene 1-octadecene, 1-nonadecene, 1-eicosene, 1-doeicosene, 2-tetracosene, 3-methyl-1-henicosene, 4-ethyl-2-tetracosene or mixtures thereof. Useful examples of an alpha-olefin include 1-pentadecene, 1-hexadecene, 1-heptadecene 1-octadecene, 1-nonadecene or mixtures thereof. The alpha-olefin is often commercially available as mixtures especially as C16-C18.
In one embodiment the polymeric dispersant viscosity modifier is derived from functionalised polyolefin, functionalised with an unsaturated carboxylic acid anhydride or derivatives thereof (described above). The functionalised polyolefin has a molecular weight (Mw) in the range including from about 600 to about 300,000, in another embodiment about 600 to about 100,000, in another embodiment about 1000 to about 50,000 and in another embodiment about 2000 to about 20,000.
The unsaturated carboxylic acid anhydride or derivatives thereof may be incorporated into olefin polymer backbone and/or grafted on to the backbone. In one embodiment the unsaturated carboxylic acid anhydride or derivatives thereof is grafted on to the backbone. In one embodiment the unsaturated carboxylic acid anhydride or derivatives thereof is incorporated into olefin polymer backbone.
In one embodiment the polymeric dispersant viscosity modifier is an esterified polymer derived from monomers comprising: (i) a vinyl aromatic monomer; and (ii) an unsaturated carboxylic acid or derivatives thereof. The polymer prior to esterification is generally referred to as an interpolymer. In one embodiment the esterified polymer is substantially free of to free of a (meth)acrylate ester. In one embodiment the interpolymer is a styrene-maleic anhydride copolymer. In one embodiment the esterified polymer contains a nitrogen derived from a nitrogen containing compound capable of reacting with a functionalised polymer backbone to form an amidated polymer.
The molecular weight of the interpolymer may also be expressed in terms of the “reduced specific viscosity” of the polymer which is recognized means of expressing the molecular size of a polymeric substance. As used herein, the reduced specific viscosity (abbreviated as RSV) is the value obtained in accordance with the formula RSV=(Relative Viscosity—1)/Concentration, wherein the relative viscosity is determined by measuring, by means of a dilution viscometer, the viscosity of a solution of about 1 g of the polymer in about 10 cm3 of acetone and the viscosity of acetone at about 30° C. For purpose of computation by the above formula, the concentration is adjusted to about 0.4 g of the interpolymer per 10 cm3 of acetone. A more detailed discussion of the reduced specific viscosity, also known as the specific viscosity, as well as its relationship to the average molecular weight of an interpolymer, appears in Paul J. Flory, Principles of Polymer Chemistry, (1953 Edition) pages 308 et seq. The interpolymer polymer of the invention has a RSV from about 0.05 to about 2 in one embodiment about 0.06 to about 1 and in another embodiment about 0.06 to about 0.8. In one embodiment the RSV is about 0.69. In another embodiment the RSV is about 0.12. In one embodiment the Mw of the interpolymer is about 10,000 to about 300,000.
Examples of a vinyl aromatic monomer include styrene (often referred to as ethenylbenzene), substituted styrene or mixtures thereof. Substituted styrene monomers include functional groups such as a hydrocarbyl group, halo-, amino-, alkoxy-, carboxy-, hydroxy-, sulphonyl- or mixtures thereof. The functional groups include those located at the ortho, meta or para positions relative to the vinyl group on the aromatic monomer, the functional groups are located at the ortho or para position being especially useful. In one embodiment the functional groups are located at the para position. Halo-functional groups include chlorine, bromine, iodine or mixtures thereof. In one embodiment the halo functional group is chlorine or mixtures thereof. Alkoxy functional groups may contain 1 to about 10 carbon atoms, in another embodiment 1 to about 8 carbon atoms, in another embodiment 1 to about 6 carbon atoms and in yet another embodiment 1 to about 4 carbon atoms. Alkoxy functional groups containing 1 to about 4 carbon atoms is referred to as lower alkoxy styrene.
The hydrocarbyl group includes ranges from 1 to about 30 carbon atoms, in another embodiment 1 to about 20 carbon atoms, in another embodiment 1 to about 15 carbon atoms and in yet another embodiment 1 to about 10 carbon atoms. Examples of a suitable hydrocarbyl group on styrene monomers include alpha-methylstyrene, para-methylstyrene (often referred to as vinyl toluene), para-tert-butylstyrene, alpha-ethylstyrene, para-lower alkoxy styrene or mixtures thereof.
The polymeric dispersant viscosity modifier is known in the art and commercially available from a number of corporations, including The Lubrizol Corporation, Degussa AG and Rohmax GmbH.
The polymeric dispersant viscosity modifier is present in the range from about 0.001 wt % to about 60 wt % of the composition, in another embodiment about 1 wt % to about 50 wt % of the composition, in another embodiment about 2 wt % to about 40 wt % of the composition and in another embodiment about 5 wt % to about 35 wt % of the composition.
Other Performance Additive
The composition of the invention optionally includes at least one other performance additive. The other performance additive includes a metal deactivator, a detergent, a dispersant, an extreme pressure agent, an antiwear agent, an antioxidant, a corrosion inhibitor, a foam inhibitor, a demulsifiers, a pour point depressant, a seal swelling agent or mixtures thereof.
The total combined amount of the other performance additive present on an oil free basis is present in the range from about 0 wt % to about 25 wt %, in another embodiment about 0.01 wt % to about 20 wt %, in another embodiment about 0.1 wt % to about 15 wt % and in yet another embodiment about 0.5 wt % to about 10 wt % of the composition. Although one or more of the other performance additives may be present, it is common for the other performance additives to be present in different amounts relative to each other.
Antiwear Agent
Optionally, the composition includes an antiwear agent. The antiwear agent may also act as an extreme pressure agent for example a sulphurised olefin. The antiwear agent may be used alone or in combination. In one embodiment the antiwear agent includes a thiocarbamate-containing compound such as thiocarbamate esters, thiocarbamate amides, thiocarbamic ethers, alkylene-coupled thiocarbamates, or bis(S-alkyldithiocarbamyl) disulphides. In one embodiment the thiocarbamate-containing compound is present. In one embodiment the thiocarbamate-containing compound is not present.
The dithiocarbamate containing compounds may be prepared by reacting a dithiocarbamate acid or salt with an unsaturated compound. The dithiocarbamates containing compounds may also be prepared by simultaneously reacting an amine, carbon disulphide and an unsaturated compound. Generally, the reaction occurs at a temperature from 25° C. to 125° C. U.S. Pat. Nos. 4,758,362 and 4,997,969 describe dithiocarbamate compounds and methods of making them.
In one embodiment the antiwear agent includes a fatty amine. Useful fatty amine compounds include those commercially available as “Armeen” (RTM) amines (products available from Akzo Chemicals, Chicago, Ill.), such as Akzo's, Armeen C, Armeen O, Armeen O L, Armeen T, Armeen H T, Armeen S and Armeen S D, wherein the letter designation relates to the fatty group, such as coco, oleyl, tallow, or stearyl groups. In one embodiment the fatty amine is present. In one embodiment the fatty amine is not present.
In one embodiment the antiwear agent includes a sulphurised olefin. Examples of the sulphurised olefin include an olefin derived from propylene, isobutylene, pentene, an organic sulphide and/or polysulphide including benzyldisulphide; bis-(chlorobenzyl) disulphide; dibutyl tetrasulphide; di-tertiary butyl polysulphide; and sulphurised methyl ester of oleic acid, a sulphurised alkylphenol, a sulphurised dipentene, a sulphurised terpene, a sulphurised Diels-Alder adduct, an alkyl sulphenyl N′N-dialkyl dithiocarbamates; or mixtures thereof. In one embodiment the sulphurised olefin includes an olefin derived from propylene, isobutylene, pentene or mixtures thereof. In one embodiment the sulphurised olefin is present. In one embodiment the sulphurised olefin is not present.
In one embodiment the antiwear agent includes a phosphosulphurised hydrocarbon. Examples include a dithiophosphate, the reaction product of phosphorus sulphide with turpentine and/or methyl oleate; a phosphorus ester including a dihydrocarbon and/or a trihydrocarbon phosphite, e.g., dibutyl phosphite, diheptyl phosphite, dicyclohexyl phosphite, pentylphenyl phosphite; dipentylphenyl phosphite, tridecyl phosphite, distearyl phosphite and polypropylene substituted phenol phosphite; or mixtures thereof.
In one embodiment the antiwear agent includes phosphorus antiwear compounds similar to the amine salt of a phosphorus compound described above, except the amine salt has been replaced partially or wholly by a valence of a metal to form a metal salt. The valence of metal includes an alkali metal, alkaline earth-metal, a transition metal or mixtures thereof. Examples of a metal include sodium, potassium, lithium, calcium, magnesium, barium, zinc or mixtures thereof.
In one embodiment the antiwear agent includes a metal hydrocarbyl dithiophosphate. Examples of a metal hydrocarbyl dithiophosphate include zinc dihydrocarbyl dithiophosphates (often referred to as ZDDP, ZDP or ZDTP). Examples of suitable zinc hydrocarbyl dithiophosphates compounds may include the reaction product(s) of heptyl or octyl or nonyl dithiophosphoric acids with ethylene diamine, morpholine or mixtures thereof. The antiwear agent is present in ranges including from about 0 wt % to about 30 wt % of the composition, in another embodiment about 0.001 wt % to 30 wt % of the composition, in another embodiment from about 0.05 wt % to about 20 wt % of the composition, in another embodiment from about 1 wt % to about 15 wt % of the composition and in another embodiment from about 0.5 wt % to about 10 wt % of the composition.
Dispersant
In one embodiment of the invention the composition further includes a dispersant. The dispersant may be used alone or in combination with other dispersant additives. The dispersant includes those derived from a N-substituted long chain alkenyl succinimide.
The N-substituted long chain alkenyl succinimide has a variety of chemical structures and includes a mono-succinimide and/or a di-succinimide. The long chain alkenyl group includes those with a number average molecular weight of about 350 to about 10,000, in another embodiment about 400 to about 7000, in another embodiment about 500 to about 5000 and in yet another embodiment about 500 to about 4000. In one embodiment the long chain alkenyl group is a polyisobutylene group, which has a number average molecular weight from 800 to 1600 and in another embodiment from about 1600 to about 3000. The succinimide includes those prepared by the condensation of a hydrocarbyl-substituted acylating agent (e.g., hydrocarbyl-substituted succinic anhydride) with a polyamine or an amino alcohol, a polyalkylene polyamine or poly(ethyleneamine) such as triethylene tetramine, tetraethylene pentamine, pentaethylene hexamine, still bottoms (often described as HPAX™) or mixtures thereof. In one embodiment the polyamine is still bottoms.
The N-substituted long chain alkenyl succinimide dispersant additives and their preparation are disclosed, for instance, in U.S. Pat. Nos. 3,361,673, 3,401,118 and 4,234,435.
Another class of dispersant includes Mannich bases, which are the reaction products of alkyl phenols in which the alkyl group includes at least about 30 carbon atoms with aldehydes (especially formaldehyde) and amines (especially polyalkylene polyamines) and are described in more detail in U.S. Pat. No. 3,634,515.
Another class of ashless dispersant is high molecular weight esters. These materials are similar to the above-described succinimides except that they may be seen as having been prepared by reaction of a hydrocarbyl acylating agent and a polyhydric aliphatic alcohol such as glycerol, pentaerythritol, or sorbitol. Such materials are described in more detail in U.S. Pat. No. 3,381,022.
The dispersant may also be post-treated by reaction with any of a variety of agents. Among these are urea, thiourea, dimercaptothiadiazoles, carbon disulfide, aldehydes, ketones, carboxylic acids, hydrocarbon-substituted succinic anhydrides, nitriles, epoxides, boron compounds, and phosphorus compounds. References detailing such treatment are listed in U.S. Pat. No. 4,654,403. In one embodiment the dispersant is borated dispersant especially a borated N-substituted long chain alkenyl succinimide or mixtures thereof. In one embodiment of the invention the borated dispersant is not present.
The dispersant is present in a ranges from about 0 wt % to about 25 wt % of the composition, in another embodiment about 0.01 wt % to about 15 wt % of the composition, in another embodiment about 0.1 wt % to about 8 wt % of the composition and in yet another embodiment about 0.5 wt % to about 4 wt % of the composition.
Detergent
The composition may further include a detergent. Detergent compounds are known and include neutral or overbased, Newtonian or non-Newtonian, basic salts of alkali, alkaline earth and transition metals with one or more of a phenate, a sulphurised phenate, a sulphonate, a carboxylic acid, a phosphorus acid, a mono- and/or a di-thiophosphoric acid, a saligenin, a salixarate, an alkylsalicylate or mixtures thereof. Commonly used metals include sodium, potassium, calcium, magnesium lithium or mixtures thereof. Most commonly used metals include sodium, magnesium and calcium. In one embodiment of the invention the detergent include a phenate, a sulphurised phenate or mixtures thereof. In one embodiment of the invention the detergent is a sulphurised phenate.
Antioxidant
The composition of the invention may further include an antioxidant. The antioxidant compounds are known and include a molybdenum dithiocarbamate, a sulphurised olefin, a hindered phenol, a diphenylamine or mixtures thereof. The antioxidant can be used alone or in combination. In one embodiment the antioxidants includes a hindered phenol, a diphenylamine or mixtures thereof.
The diphenylamine antioxidant includes those with a mono- or a di-alkylated phenyl ring. Examples of suitable diphenylamine antioxidant include bis-nonylated diphenylamine, nonyl diphenylamine, octyl diphenylamine, bis-octylated diphenylamine, bis-decylated diphenylamine, decyl diphenylamine or mixtures thereof.
The hindered phenol antioxidant includes a secondary butyl and/or a tertiary butyl group as a sterically hindering group. The phenol group optionally further includes a substituted hydrocarbyl group and/or a bridging group linking to a second aromatic group. Examples of suitable hindered phenol antioxidant include 2,6-di-tert-butylphenol, 4-methyl-2,6-di-tert-butylphenol, 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 or mixtures thereof. In one embodiment the hindered phenol antioxidant is an ester, for example, Irganox®L-135 a commercially available product from Ciba. Specialty Chemicals.
Suitable examples of molybdenum dithiocarboamate include commercial materials sold under the trade names such as Vanlube 822™ and Molyvan™ A from R. T. Vanderbilt Co., Ltd., and Adeka Sakura-Lube™ S-100 and S-165 and S-600 from Asahi Denka Kogyo K. K.
The other performance additive compounds such as a metal deactivator include a benzotriazole; a 1,2,4-triazole, a thiadiazole; a corrosion inhibitor include octylamine octanoate, condensation products of dodecenyl sliccinic acid or anhydride and a fatty acid such as oleic acid with a polyamine; a foam inhibitor include a copolymer of (a) ethyl acrylate; (b) 2-ethylhexylacrylate and (c) optionally vinyl acetate; a demulsifier include trialkyl phosphates, polyethylene glycols, polyethylene oxides, polypropylene oxides and (ethylene oxide-propylene oxide) polymers; a pour point depressant include polyacrylamides or polymers other than component (b) of the invention such as esters of maleic anhydride-styrene, poly(meth)acrylates, polyacrylates; and a seal swell agent include Exxon Necton-37™ (FN 1380) and Exxon Mineral Seal Oil (FN 3200); may also be used in the composition of the invention.
The invention further provides a method comprising lubricating a surface while imparting deposit control, the method employing a composition comprising:
The surface is usually metallic and in one embodiment ferrous. In one embodiment of the method, the wear preventing agent is present. Deposit control includes sludge and other deposits. In one embodiment deposit control is reduced sludge accumulation.
Process
The invention further provides a process for the preparation of a composition comprising mixing:
Components (a)-(c) are mixed sequentially and/or separately to form the composition of the invention. The mixing conditions include a temperature in the range from about 15° C. to about 130° C., in another embodiment about 20° C. to about 120° C. and in another embodiment about 25° C. to about 110° C.; and for a period of time in the range about 30 seconds to about 48 hours, in another embodiment about 2 minutes to about 24 hours, in another embodiment about 5 minutes to about 16 hours and in yet another embodiment about 10 minutes to about 5 hours; and at pressures in the range about 86 kPa to about 266 kPa (about 650 mm Hg to about 2000 mm Hg), in another embodiment about 91 kPa to about 200 kPa (about 690 mm Hg to about 1500 mm Hg), and in another embodiment about 95 kPa to about 133 kPa (about 715 mm Hg to about 1000 mm Hg).
The process optionally includes mixing other optional performance additives as described above. In one embodiment the process provides a process for the preparation of a concentrate. The optional performance additives may be added sequentially, separately or as a concentrate.
The composition of the present invention is useful for a gear or bearing lubricant. The use of the composition described above is capable of imparting one or more performance characteristics including deposit control, reduced carbon varnish, decreased wear, low temperature viscometrics, high temperature viscometrics or mixtures thereof. In one embodiment the composition of the invention is capable of improving one or more of the performance characteristics listed above.
The following examples provide an illustration of the invention. These examples are non exhaustive and are not intended to limit the scope of the invention.
A container is charged with about 120.1 parts methyl methacrylate, about 722.4 parts C12-C15 alkylmethacrylate, about 6 parts n-dodecylmercaptan, 6 parts t-butylperoctoate (Akzo Trigonox-21) and about 242.0 parts of Total 85N oil, followed by stirring for about 0.25 hours. A reactor equipped with a stirrer, thermocouple reaching into the charged reaction mixture, N2 inlet atop an addition funnel attached to a subsurface tube, and water condenser is charged with about ⅓ of the monomer-initiator solution and about 15.4 parts dimethylaminopropylmethacrylamide. The remainder of the monomer-initiator mixture is placed in the addition funnel. With N2 addition at about 0.3 litres per hour and stirring, the mixture is heated to about 110° C. over about 0.3 hour, heating is stopped and an exotherm to about 143° C. over about 0.1 hours is observed. The temperature begins to drop and dropwise addition of the remaining solution is begun. Addition time is about 90 minutes; about 0.4 hours after the peak exothermic temperature, the temperature is about 110° C. The temperature during addition is maintained at about 110° C. The reaction is held at about 110° C. for one hour about 1.5 parts of t-butylperoctoate and about 3.5 parts of Total 85N oil is charged to the reaction, the reaction is held at about 110° C. for one hour. Another about 1.5 parts of t-butylperoctoate and about 3.5 parts of Total 85N oil is charged and the reaction is held at about 110° C. for two hours. The resulting product has Mw=68,800 and polydispersity (Mw/Mn)=1.90.
Prepared in same process as Preparative Example of PMA DVM except Dimethylaminopropylmethacrylamide is not added.
A Polymeric Dispersant Viscosity Modifier derived from a maleic anhydride-styrene interpolymer is prepared in a reactor charged with about 2498.7 parts of about 11.6% solids in toluene slurry of a maleic anhydride/styrene (1:1 mole ratio) copolymer having a RSV=0.08, and about 500.3 parts Alfol 1218 (a mixture of predominantly straight chain primary alcohols having from 12 to 18 carbon atoms). The materials are heated to about 120° C. with N2 blowing while removing toluene. A mixture of about 15.8 parts methane sulphonic acid and about 82.8 parts Alfol 810 (a mixture of predominantly straight chain primary alcohols having from 8 to 10 carbon atoms), is added over about 0.5 hour, heating is begun while removing water and excess toluene, stabilising at about 135° C. The reaction is continued for about 18 hours, removing water as toluene-water azeotrope. An aliquot has total acid number=6.1 and strong acid number=3.7, net=2.4, about 98% esterified. The temperature is raised to about 150° C. The strong acid is neutralized with about 5.6 parts 50% aqueous NaOH added dropwise and held for about 0.5 hour. Then about 3.0 parts aminopropylmorpholine are added over about 0.2 hour followed by heating for 1 hour. An alkylated diphenylamine is added (3.0 parts) and the materials are stripped to 150° C. and at about 2.5 kPa (equivalent to about 20 mm Hg pressure). A light mineral oil (S0-44) (218 parts) is added and after mixing, the oil solution is filtered to yield 870 parts (80.0% of theory) of product.
Prepared in same process as Preparative Example of esterified Maleic anhydride Styrene DVM except aminopropylmorpholine is not added.
Example 1 (Ex 1) was prepared by mixing in about 78.5 wt % of EMERY® 3008 PAO oil of lubricating viscosity about 14.5 wt % of a dispersant polymethacrylate of Preparative Example 1 and about 6.4 wt % of a mixture of a sulphurised isobutylene and an alkylamine salt of a phosphoric acid (Primene® 81R). Example 2 (Ex 2) is prepared the same way as Example 1 except about 1.6 wt % of a borated dispersant is added. Reference Examples 1 and 2 (Ref 1 and Ref 2) were prepared the same way as Example 1 and 2 respectively, except the dispersant polymethacrylate is replaced with a non-dispersant polymethacrylate.
Examples 3 (Ex 3) and 4 (Ex 4) were prepared by the process of Examples 1 and 2. The only exception is the dispersant polymethacrylate is replaced by 11 wt % of dispersant polyolefin (PA-1160, commercially available from DSM) and EMERY® 3008 PAO oil of lubricating viscosity is present at about 82 wt %. Reference Examples 3 (Ref 3) and 4 (Ref 4) were prepared by the same process as Examples 3 and 4 except, the PA-1160 was replaced by about 7.5 wt % of polyolefin (Lucantg HC-2000 commercially available from Mitsui Chemicals America, Inc.).
Examples 5 (Ex 5) and 6 (Ex 6) were prepared by were prepared by the process of Examples 1 and 2. The only exception is the dispersant polymethacrylate is replaced by about 22 wt % of a dispersant esterified styrene-maleic anhydride interpolymer and the EMERY® 3008 PAO oil of lubricating viscosity at about 71 wt %. Reference Examples 5 (Ref 5) and 6 (Ref 6) were prepared by the same process as Examples 5 and 6 except, the dispersant esterified styrene-maleic anhydride interpolymer is replaced by a non-dispersant esterified styrene-maleic anhydride interpolymer.
Test 1: Oxidation Stability Test
The Oxidation Stability test was carried out based on a modified Coordinating European Council (CEC) test method CEC-L-48-A-00. The modified test conditions used were a test tube is filled with about 90 g sample and heated to about 160° C. for a period of about 72 hours with an air flow of about 83 cc min−1. The test procedure measures a tube rating, % viscosity increase (at 40° C. and 100° C.) and spot rating. A lighter tube rating indicates decreased deposit formation on the tube. Higher spot ratings indicate reduced amounts of particulate matter being produced. The results obtained were:
The analysis of the experimental data obtained for the following combinations of reference examples and invention examples Ex 1 with Ref 1; Ex 2 with Ref 2; Ex 3 with Ref 3; Ex 4 with Ref 4; Ex 5 with Ref 5; and Ex 6 with Ref 6 shows that the composition of the invention produces decreased amounts of deposit formation over the corresponding reference example.
In summary the composition of the invention is capable of imparting one or more performance characteristics including deposit control, reduced carbon varnish, decreased wear, low temperature viscometrics, high temperature viscometrics or mixtures thereof.
While the invention has been explained, it is to be understood that various modifications thereof will become apparent to those skilled in the art upon reading the specification. Therefore, it is to be understood that the invention disclosed herein is intended to cover such modifications as fall within the scope of the appended claims.
