Patent Application
20250051677
The present disclosure relates to lubricating compositions having improved cold properties. More particularly, the present application concerns the use of a specific polymer to improve the cold thickening properties of a lubricating composition.
Lubricating compositions comprise numerous additives and in particular additives of detergent type. A change in type of detergent can have a major impact on the performance of lubricating compositions and in particular on the Gelation Index. For example, it has been shown that a partial change in the type of detergent (e.g. calcium detergent) by a magnesium detergent (the formula being equivalent) generates a failed Gelation Index test, indicating thickening of the lubricating composition at very low temperature). Yet, successful passing of this test is compulsory in particular to obtain approval by the American Petroleum Institute (API).
In general, for successful passing of this Gelation Index, it is known to act on conventional parameters of viscosity. It is therefore necessary to seek to decrease viscosity by acting on conventional parameters such as choice of base oil or choice of polymer as pour point depressant (PPD). However, in some cases these changes do not allow passing of this test.
There would therefore an advantage in providing a solution and in identifying additives allowing an improvement in the cold thickening properties of lubricating compositions.
It is one objective of the present invention to provide additives allowing an improvement in the cold thickening properties of lubricating compositions, in particular when changes are made to the type of detergents contained in lubricating compositions.
A further objective of the present invention is to provide a lubricating composition having good cold thickening properties.
Other objectives will become apparent on reading the following description of the invention.
These objectives are met with the present application which concerns the use of a comb polymer comprising repeating units that are able to be obtained by polymerization of monomers (a) of formula (I):
Improvement in cold thickening properties is determined in relation to the same lubricating composition but not containing the comb polymer.
In the present invention, cold thickening corresponds to the Gelation Index. The Gelation Index and the method for measuring the same are described in particular in standard ASTM D1533-20a (2020). The Gelation Index corresponds to measurement of the apparent viscosity of the engine oil at low temperature. The resulting measurement of this test is the maximum rate of increase in viscosity.
Grade (X)W—(Y) corresponds herein to the grade of the final lubricating composition, and not to that of the base oil alone.
Preferably, in the present invention, the comb polymer also comprises units derived from monomers (b) of formula (II):
Preferably, R1 is a methyl group.
Among the examples of C2-C4 alkylene groups, mention can be made in particular of an ethylene group, a 1,2- or 1,3-propylene group, or a 1,2, 1,3- or 1,4-butylene group. Preferably, m is an integer ranging from 0 to 4, more preferably from 0 to 2.
If m is higher than or equal to 2, each A can be the same or different, and the fragments (AO)m can be bonded randomly or in blocks.
Preferably, group X1 is a group —O— or —O(AO)m—, more preferably a group —O— or —O(CH2CH2O)—.
R2 is a polybutylene group.
By «polybutylene group», in the meaning of the invention, it is meant a group obtained by removal of a hydrogen atom from a hydrocarbon polymer having as essential structural unit at least one monomer of 1,2 butylene or isobutylene type.
As an example of hydrocarbon polymer suitable for preparing a polybutylene group R2, particular mention can be made of a copolymer comprising units derived from isobutylene and/or from 1,2-butylene, or a polymer obtained by hydrogenation of the terminal double bond of a polybutadiene obtained by 1,2 addition of buta-1,3-diene monomers.
The hydrocarbon polymer can be a block polymer or a statistical polymer.
The hydrocarbon polymer may further contain at least one structural repeating unit differing from the isobutylene or 1,2-butylene repeating units.
The hydrocarbon polymer may for example comprise one or more of the following repeating units:
If the hydrocarbon polymer has a double bond, this double bond can be fully or partially hydrogenated by hydrogenation.
Preferably, the isobutylene and 1,2-butylene repeating units represent at least 30 mole % of the total number of structural units forming the hydrocarbon polymer, preferably at least 40 mole %, preferably at least 50 mole %, preferably at least 60 mole %.
The total number of butylene units (isobutylene and/or 1,2 butylene), relative to the total number of structural units of the hydrocarbon polymer can be determined by analyzing the hydrocarbon polymer under 13C nuclear magnetic resonance spectroscopy and using the following equation:
The 13C nuclear magnetic resonance spectrum shows a peak derived from a methyl group of isobutylene at 30-32 ppm (integration value A), and a peak derived from a branched methylene group (—CH2—CH(CH2CH3)—) of 1,2-butylene at 26-27 ppm in integrated value (integration value B). The total number of isobutylene and 1,2-butylene units can be determined from the integration values of the peaks and from an integration value (integration value C) of the peaks of all the carbon atoms of the hydrocarbon polymer.
The monomers (a) are typically obtained by esterification or amidation of a (co)polymer (Y) containing a hydroxyl group or an amine group.
Among the examples of (co)polymers (Y) (i.e. the (co)polymer containing a hydroxyl group or an amine group), mention can be made as examples of the (co)polymers (Y1) to (Y4) containing a hydroxyl group, and the (co)polymers (Y5) containing an amine group such as defined below.
Alkylene oxide adducts (Y1): (co)polymers able to be obtained by contacting an alkylene oxide, for example ethylene oxide or propylene oxide, with a polymer chosen from among: (1) a hydrocarbon polymer obtained by polymerization of an unsaturated aliphatic hydrocarbon; (2) an unsaturated alicyclic hydrocarbon; (3) an unsaturated aromatic hydrocarbon chosen in particular from among C2-C36 olefins and derivatives thereof in the presence of an ionic polymerization catalyst e.g. a sodium catalyst.
The products obtained by hydroboration (Y2): (co)polymer able to be obtained by hydroboration of hydrocarbon polymers in particular the one described in U.S. Pat. No. 4,316,973.
Adducts of maleic anhydride-ene-amino alcohol type (Y3): (co)polymers able to be obtained by imidization of the product obtained by Alder-ene reaction between a hydrocarbon polymer having a double bond and maleic anhydride in the presence of an amino alcohol.
The products able to be obtained by hydroformylation and hydrogenation (Y4): (co)polymer(s) able to be obtained by hydroformylation of a hydrocarbon polymer having a double bond, followed by a hydrogenation step. Mention can be made for example of the products described in JP-A 63-175096.
Maleic anhydride-ene-ethylene diamine adducts (Y5): (co)polymers able to be obtained by imidization of a product obtained by Alder-ene reaction between a hydrocarbon polymer having a double bond and maleic anhydride in the presence of ethylenediamine.
Preferably, the (co)polymer (Y) is chosen from among the (co)polymers (Y1), (Y2), and (Y3), more preferably from among the (co)polymers (Y) and (Y1).
The number average molecular weight (Mn) of each of the (co)polymers (Y) is preferably from 1 000 to 25 000 g·mol−1, more preferably from 2 000 to 20 000 g·mol−1, particularly preferably from 3 000 to 15 000 g·mol−1, further preferably from 4 000 to 10 000 g·mol−1.
Advantageously, the crystallization temperature of (co)polymer (Y) is lower than or equal to −40° C., more preferably lower than or equal to −50° C., in particular lower than or equal to −55° C., typically lower than or equal to −60° C.
The crystallization temperature of (co)polymer (Y) or of (co)polymer (A) can be measured by differential scanning calorimetry of “Unix® DSC7» type (PerkinElmer). The crystallization temperature is measured at the time of isothermal cooling of a sample (5 mg) of (co)polymer (Y) or of (co)polymer (A) from 100° C. to −80° C. at a rate of 10° C./min.
In one embodiment, the copolymer also comprises repeating units able to be obtained by polymerization of monomers (b) of formula (II):
Preferably, R3 is a methyl group.
Preferably, X2 is a group —O—.
As examples of C2-C4 alkylene groups, particular mention can be made of ethylene, isopropylene, 1,2- or 1,3-propylene, isobutylene and 1,2-, 1,3- or 1,4-butylene.
Preferably, q is 1 or 2.
When q is equal to or higher than 2, each R4 can be the same or different, and the fragments (R4O)q can be bonded randomly or in blocks.
As examples of C1-C8 alkyl groups, particular mention can be made of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-heptyl, isoheptyl, n-hexyl, 2-ethylhexyl, n-pentyl and n-octyl groups.
Among these C1-C8 alkyl groups, preference is given to C1-C6alkyl groups, more preferably to C1-C5 alkyl groups, typically C4 alkyl groups.
Among the examples of monomers (b), mention can be made of methoxypropyl (meth)acrylate, methoxybutyl (meth)acrylate, methoxyheptyl (meth)acrylate, methoxyhexyl (meth)acrylate, methoxypentyl (meth)acrylate, methoxyoctyl (meth)acrylate, ethoxyethyl (meth)acrylate, ethoxypropyl (meth)acrylate, ethoxybutyl (meth)acrylate, ethoxyheptyl (meth)acrylate, ethoxyhexyl (meth)acrylate, ethoxypentyl (meth)acrylate, ethoxyoctyl (meth)acrylate, propoxymethyl (meth)acrylate, propoxyethyl (meth)acrylate, propoxypropyl (meth)acrylate, propoxybutyl (meth)acrylate, propoxyheptyl (meth)acrylate, propoxyhexyl (meth)acrylate, propoxypentyl (meth)acrylate, propoxyoctyl (meth)acrylate, butoxymethyl (meth)acrylate, butoxyethyl (meth)acrylate, butoxypropyl (meth)acrylate, butoxybutyl (meth)acrylate, butoxyheptyl (meth)acrylate, butoxyhexyl (meth)acrylate, butoxypentyl (meth)acrylate, butoxyoctyl (meth)acrylate and the esters of (meth)acrylic acid and C1-C8 alcohols with 2 to 20 moles of ethylene oxide, propylene oxide or butylene oxide.
In the meaning of the present invention, the term «(meth)acrylate» designates a methacrylate or an acrylate. By analogy in the meaning of the present invention, the term «(meth)acrylamide» designates a methacrylamide or an acrylamide.
Advantageously, the monomers (b) are chosen from among ethoxyethyl (meth)acrylate and butoxyethyl (meth)acrylate.
In one preferred embodiment, monomers (b) differ from monomers (a).
In one embodiment the copolymer of the invention, in addition to the units derived from monomers (a) and (b), may also comprise additional repeating units able to be obtained by polymerization of monomers chosen from among:
As examples of monomers (c), particular mention can be made of: methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate and butyl (meth)acrylate.
Preferably, monomers (c) are chosen from among methyl (meth)acrylate and butyl (meth)acrylate, more preferably from among butyl (meth)acrylates.
As examples of monomers (d), particular mention can be made of: n-dodecyl (meth)acrylate, n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, n-pentadecyl (meth)acrylate, n-hexadecyl (meth)acrylate, n-octadecyl (meth)acrylate, n-icosyl (meth)acrylate, n-tetracosyl (meth)acrylate, n-triacontyl (meth)acrylate and n-hexatriacontyl (meth)acrylate.
Preferably the monomers (d) are chosen from among alkyl (meth)acrylates having a C12-C28 linear alkyl group, more preferably from among alkyl (meth)acrylates having a C12-C22 linear alkyl group.
The (co)polymer of the invention may also contain repeating units able to be obtained by polymerization of monomers (e) represented by following formula (III):
Preferably, R6 is a methyl group.
Preferably, X3 is a group —O—.
As examples of C2-C4 alkylene groups, particular mention can be made of ethylene, isopropylene, 1,2- or 1,3-propylene, isobutylene and the 1,2-, 1,3- or 1,4-butylene groups. Preferably, r is an integer ranging from 0 to 5, more preferably from 0 to 2.
When r is higher than or equal to 2, the groups R7 can be the same of different, and the fragments (R7O) can be bonded randomly or in blocks.
As examples of C4-C24 linear alkyl groups, particular mention can be made of n-butyl, n-heptyl, n-hexyl, n-pentyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tetradecyl, n-hexadecyl, n-octadecyl, n-eicosyl and n-tetracosyl groups.
Preferably, the groups R8 and R9 are each independently chosen from among C6-C24 linear alkyl groups, more particularly from among C6-C20 linear alkyl groups, typically from among C8-C16 linear alkyl groups.
As examples of monomers (e), particular mention can be made of: 2-octyldecyl (meth)acrylate, an ester of ethylene glycol mono-2-octylpentadecyl ether and (meth)acrylic acid, 2-octyldodecyl (meth)acrylate, 2-n-decyltetradecyl (meth)acrylate, 2-n-(meth)acrylate, 2-tetradecyloctadecyl (meth)acrylate, 2-dodecylhexadecyl dodecylpentadecyl (meth)acrylate, 2-tetradecylheptadecyl (meth)acrylate, 2-hexadecylheptadecyl (meth)acrylate, 2-heptadecyleicosyl (meth)acrylate, 2-hexadecyldocosyl (meth)acrylate, 2-eicosyldocosyl (meth)acrylate, 2-tetracosylhexacosyl (meth)acrylate and N-2-octyldecyl (meth)acrylamide.
Preferably, monomers (e) are chosen from among alkyl (meth)acrylates in which the alkyl group is chosen from among C12-C36 branched alkyl groups, more preferably C14-C32, typically C16-C28.
Monomers (b) to (e) are obtained by reacting a terminal hydroxy group or an amine group of a compound comprising a hydrocarbon group with a (meth)acrylic acid, but not by modifying a hydrocarbon polymer. Therefore, the monomers (b) to (e) are not polyolefin-based monomers. Also, those obtained through the addition of 2 to 20 moles of ethylene oxide, propylene oxide or butylene oxide to C1-C8 alcohols, and those obtained through the addition of 1 to 20 moles of ethylene oxide, propylene oxide or butylene oxide to alcohols containing C10-C50 branched alkyl groups are not obtained either by modifying hydrocarbon polymers. Therefore, these monomers are not polyolefin-based monomers.
In one embodiment, the (co)polymer of the invention, in addition to the units derived from monomers (a) to (e), comprise repeating units obtained by polymerization of monomers chosen from the group formed by:
Among the examples of monomers (f), mention can be made of the following monomers (f1) to (f4):
Examples of monomers (f1): (meth)acrylamides; monoalkyl (meth)acrylamides, in particular those in which a C1-C4 alkyl group is bonded to a nitrogen atom such as for example N-methyl (meth)acrylamide, N-ethyl (meth)acrylamide, N-isopropyl (meth)acrylamide, N-n-butyl (meth)acrylamide and N-isobutyl (meth)acrylamide]; N—(N′-monoalkylaminoalkyl)(meth)acrylamides in particular those having a C2-C6 aminoalkyl group in which a C1-C4 alkyl group is bonded to a nitrogen atom such as for example N—(N′-methylaminoethyl)(meth)acrylamide, N—(N′-ethylaminoethyl)(meth)acrylamide, N—(N′-isopropylamino-n-butyl)(meth)acrylamide, N—(N′-n-butylamino-n-butyl)(meth)acrylamide, and N—(N′-isobutylamino-n-butyl)(meth)acrylamide; dialkyl (meth)acrylamides in particular those in which two C1-C4 alkyl groups are bonded to a nitrogen atom such as for example N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, N,N-diisopropyl (meth)acrylamide and N,N-di-n-butyl (meth)acrylamide; N—(N′,N′-dialkylaminoalkyl)(meth)acrylamides in particular those comprising a C2-C6 aminoalkyl group in which two C1-C4 alkyl groups are bonded to a nitrogen atom of an aminoalkyl group such as for example N—(N′,N′-dimethylaminoethyl)(meth)acrylamide, N—(N′,N′-diethylaminoethyl)(meth)acrylamide, N—(N′,N′-dimethylaminopropyl)(meth)acrylamide, and N—(N′,N′-di-n-butylaminobutyl)(meth)acrylamide; the amides of N-vinylcarboxylic acids such as for example N-vinylformamide, N-vinylacetamide, the amide of N-vinyl-n-isopropionic acid, the amide of N-vinyl-isopropionic acid and N-vinylhydroxyacetamide.
Example of monomer (f2): 4-nitrostyrene.
Examples of monomers (f3):
Example of monomer containing a nitrile group (f4): (meth)acrylonitrile.
Preferably, the monomers (f) are chosen from among monomers (f1) and (f3), more preferably from among N—(N′,N′-diphenylaminoethyl)(meth)acrylamide, N—(N′,N′-dimethylaminoethyl)(meth)acrylamide, N—(N′,N′-diethylaminoethyl)(meth)acrylamide, N—(N′,N′-dimethylaminopropyl)(meth)acrylamide, N,N-dimethylaminoethyl (meth)acrylate and N,N-diethylaminoethyl (meth)acrylate.
As examples of monomers (g), particular mention can be made of:
The monomers (h) are chosen in particular from among the following monomers (h1) and (h2).
Examples of monomers (h1): C2-C4 esters of (meth)acryloyloxyalkyl phosphate such as for example (meth)acryloyloxyethyl phosphate and (meth)acryloyloxyisopropyl phosphate; alkenyl phosphate esters such as for example vinyl phosphate, allyl phosphate, propenyl phosphate, isopropenyl phosphate, butenyl phosphate, pentenyl phosphate, octenyl phosphate, decenyl phosphate and dodecenyl phosphate. The term “(meth)acryloyloxy” designates acryloyloxy or methacryloyloxy.
Examples of monomers (h2): C2-C4 alkyl (meth)acryloyloxy phosphonic acids such as for example (meth)acryloyloxyethyl phosphonic acid; C2-C12 alkenyl phosphonic acids such as for example vinylphosphonic acid, allylphosphonic acid and octenylphosphonic acid.
Preferably, monomers (h) are chosen from among monomers (h1), more preferably from among the C2-C4 esters of (meth)acryloyloxyalkyl phosphate, advantageously monomers (h) are (meth)acryloyloxyethyl phosphate.
In one embodiment, the (co)polymer of the invention, in addition to the units derived from monomers (a) to (h), comprises repeating units obtained by polymerisation of monomers (i) comprising at least two unsaturated groups.
Among the examples of monomers (i), mention can be made of divinylbenzene; C4-C12 alkadienes such as for example butadiene, isoprene, 1,4-pentadiene, 1,6-heptadiene and 1,7-octadiene; (di)cyclopentadiene; vinylcyclohexene and ethylidene-bicycloheptene, limonene, ethylene di(meth)acrylate, the di(meth)acrylate of polyalkylene oxide glycol, pentaerythritol triallyl ether, trimethylolpropane tri(meth)acrylate, and the esters disclosed in WO 01/009242 such as for example a glycol ester of an unsaturated carboxylic acid having a number average molecular weight (Mn) higher than or equal to 500 g·mol−1 or an ester of an unsaturated alcohol and a carboxylic acid.
The (co)polymer of the invention, in addition to the units derived from monomers (a) to (i), may also comprise repeating units obtained by polymerisation of monomers chosen from among:
Examples of monomer (j): C2-C20 alkenes such as for example ethylene, propylene, butene, isobutylene, pentene, heptene, diisobutylene, octene, dodecene and octadecene.
Examples of monomer (k): cyclopentene, cyclohexene, cycloheptene, cyclooctene and pinene.
Examples of monomers (l): styrene, α-methylstyrene, vinyltoluene, 2,4-dimethylstyrene, 4-ethylstyrene, 4-isopropylstyrene, 4-butylstyrene, 4-phenylstyrene, 4-cyclohexylstyrene, 4-benzylstyrene, 4-crotylbenzene, indene and 2-vinylnaphthalene.
Examples of monomers (m): C2-C12 vinyl esters of saturated fatty acids such as for example vinyl acetate, vinyl propionate, vinyl butyrate and vinyl octanoate; C1-C12 ethers of alkyls, or aryls or of alkoxyalkylvinyls (methylvinyl ether, ethylvinyl ether, propylvinyl ether, butyl vinyl ether; 2-ethylhexyl vinyl ether; phenyl vinyl ether; vinyl-2-methoxyethyl ether; and vinyl-2-butoxyethyl ether); and C1-C8 alkyl or aryl vinyl ketones (such as for example methyl vinyl ketone, ethyl vinyl ketone, and phenyl vinyl ketone).
Examples of monomers containing an epoxy group (n): glycidyl (meth)acrylate and (meth)allyl glycidyl ether.
Examples of monomers containing a halogen (o): vinyl chloride, vinyl bromide, vinylidene chloride, (meth)allyl chloride and halogenated styrenes such as for example dichlorostyrene.
Examples of monomers of unsaturated polycarboxylic acid ester type (p): the alkyl, cycloalkyl or aralkyl esters of unsaturated polycarboxylic acids [C1-C8 alkyl diesters (dimethyl maleate, dimethyl fumarate, diethyl maleate and dioctyl maleate) of unsaturated dicarboxylic acids (such as maleic acid, fumaric acid and itaconic acid)].
The composition of the copolymer can be determined by proton nuclear magnetic resonance spectroscopy (1H NMR) or by gas phase chromatography coupled with mass spectrometry (GC-MS).
Preferably, monomers (a) represent from 1% to 50% by weight relative to the total weight of the (co)polymer, more preferably from 5% to 40% by weight, in particular from 8% to 40% by weight, typically from 10% to 30% by weight.
Preferably, monomers (b) represent from 1% to 80% by weight relative to the total weight of the (co)polymer, more preferably from 5% to 60% by weight, in particular from 10% to 35% by weight, typically from 10% to 30% by weight.
Preferably, monomers (a) and (b) together represent at least 10% by weight of the total weight of the (co)polymer, more preferably from 15% to 90% by weight, in particular from 20% to 80% by weight, typically from 20% to 50% by weight.
Preferably, monomers (c) represent from 1% to 80% by weight relative to the total weight of the (co)polymer, more preferably from 20% to 70% by weight, in particular from 30% to 65% by weight.
Preferably, monomers (d) represent from 1% to 40% by weight relative to the total weight of the (co)polymer, more preferably from 1% to 35% by weight, in particular from 2% to 30% by weight.
Preferably, monomers (e) represent from 0% to 40% by weight relative to the total weight of the (co)polymer, more preferably from 1% to 30% by weight, in particular from 1% to 25% by weight.
Preferably, monomers (f), (h) and (h) each represent from 0% to 15% by weight relative to the total weight of the (co)polymer, more preferably from 1% to 12% by weight, in particular from 2% to 10% by weight.
Preferably, monomers (i) represent from 0.01 ppm to 200 ppm by weight relative to the total weight of the (co)polymer, more preferably from 0.005 ppm to 50 ppm by weight, in particular from 0.1 ppm to 20 ppm by weight.
Preferably, monomers (j) to (p) each represent from 0 ppm to 10% by weight relative to the total weight of the (co)polymer, more preferably from 1% to 7% by weight, in particular from 2% to 5% by weight.
Preferably, the (co)polymer has a weight average molecular weight (Mw) of 5 000 g·mol−1 to 2 000 000 g·mol−1, more preferably from 150 000 g·mol−1 to 1 000 0000 g·mol−1, in particular from 230 000 g·mol−1 to 1 000 000 g·mol−1, more particularly from 300 000 g·mol−1 to 800 000 g·mol−1. The weight average molecular weight can be determined by size exclusion chromatography with poly(methyl methacrylate) (PMMA) calibrations.
The (co)polymer preferably has a crystallization temperature lower than or equal to −30° C., more preferably lower than or equal to −40° C., in particular lower than or equal to −50° C., typically lower than or equal to −60° C.
The (co)polymer used in the invention can be synthesized using any method well known to persons skilled in the art, or can be obtained commercially.
Specific examples comprise a method in which the monomers are subjected to solution polymerisation in a solvent in the presence of a polymerisation catalyst.
Among examples of solvent, mention can be made of toluene, xylene, C9-C10 alkylbenzenes, methylethylketone and mineral oils.
Examples of polymerisation catalysts: azo catalysts (such as 2,2′-azobis(2-methylbutyronitrile) and 2,2′-azobis(2,4-dimethylvaleronitrile)), peroxide catalysts (such as benzoyl peroxide, cumyl peroxide and lauryl peroxide) and redox catalysts (such as mixtures of benzoyl peroxide and tertiary amines). If necessary, a known chain transfer agent (such as C2-C20 alkylmercaptans) can also be used.
The polymerisation temperature is preferably from 25° C. to 140° C., more preferably from 50° C. to 120° C.
The comb polymer of the invention (or (co)polymer) can also be obtained by bulk, emulsion, or suspension polymerisation.
When the (co)polymer is a copolymer, it can be one of the following types: a random addition polymer, an alternating copolymer, a graft copolymer, and a block copolymer.
The comb polymer of the invention is used in the lubricating composition, preferably in an amount ranging from 1 to 20%, preferably from 4 to 16%, by weight relative to the total weight of the lubricating composition.
The lubricating composition of the invention may comprise one or more friction modifiers comprising molybdenum, so that the amount of molybdenum in the lubricating composition ranges from 100 ppm to 1500 ppm by weight, preferably from 300 ppm to 1000 ppm by weight, more preferably from 500 ppm to 1000 ppm by weight, relative to the total weight of the lubricating composition.
The quantity of molybdenum element, in particular of MoDTC compounds, in the lubricating composition of the invention can be measured in accordance with standard ASTM D5185.
In one embodiment, the lubricating composition comprises from 0.01% to 10% by weight, preferably from 0.1% to 5% by weight, more preferably from 0.5% to 3% by weight of molybdenum friction modifiers, relative to the total weight of the lubricating composition.
Preferably, the friction modifier(s) comprising molybdenum are chosen from among organomolybdenum compounds, in particular from among dithiocarbamate derivatives of molybdenum (MoDTC), dithiophosphate derivatives of molybdenum (MoDTP) or sulfur-free molybdenum complexes, further preferably from among dithiocarbamate derivatives of molybdenum (MoDTC).
The dithiocarbamate compounds of molybdenum (MoDTC compound) are complexes formed of a metal core bonded to one or more ligands independently chosen from among alkyl dithiocarbamate groups. The MoDTC compound of the compositions of the invention may comprise from 1% to 40%, preferably from 2% to 30%, more preferably from 3% to 28%, further preferably from 4% to 15% by weight of molybdenum relative to the total weight of the MoDTC compound.
The MoDTC compound used in the invention can be chosen from among compounds having a core comprising two molybdenum atoms (dimeric MoDTCs) and compounds having a core comprising three molybdenum atoms (trimeric MoDTCs).
Trimeric MoDTC compounds generally have the formula Mo3SkLn where:
As examples of trimeric MoDTC compounds, mention can be made of the compounds and methods for preparing the same described in patent application WO-98-26030.
Preferably, the MoDTC compound used in the lubricating composition of the invention is a dimeric MoDTC compound. As examples of dimeric MoDTC compounds, mention can be made of the compounds and methods for preparing the same described in patent application EP-0757093.
Dimeric MoDTC compounds are generally of formula (A):
Advantageously, R1, R2, R3 and R4, the same or different, are each independently an alkyl group having 4 to 18 carbon atoms or an alkenyl group having 2 to 24 carbon atoms.
Also advantageously, X1, X2, X3 and X4 can be the same and can represent a sulfur atom, or can be the same and represent an oxygen atom. Also advantageously, X1 and X2 can represent a sulfur atom and X3 and X4 can represent an oxygen atom. Also advantageously, X1 and X2 can represent an oxygen atom and X3 and X4 can represent a sulfur atom.
The MoDTC compound of formula (A) can also be chosen from among at least one symmetric MoDTC compound, at least one asymmetric MoDTC compound and combinations thereof. By symmetric MoDTC compound, it is particularly meant a MoDTC compound of formula (A) in which the groups R1, R2, R3 and R4 are the same, or a compound of formula (A) in which the groups R1 and R3 are the same and the groups R2 and R4 are the same. By asymmetric MoDTC compound, it is meant a MoDTC compound of formula (A) in which the groups R1 and R2 are the same, the groups R3 and R4 are the same, and the groups R1 and R2 differ from groups R3 and R4.
Advantageously, the lubricating composition of the invention may comprise a mixture of at least one symmetric MoDTC compound and at least one asymmetric MoDTC compound. More advantageously, R1 and R2, the same, then represent an alkyl group having 5 to 15 carbon atoms, and R3 and R4 the same and differing from R1 and R2 represent an alkyl group having 5 to 15 carbon atoms. Preferably, R1 and R2, the same, represent an alkyl group having 6 to 10 carbon atoms, and R3 and R4 represent an alkyl group having 10 to 15 carbon atoms.
Similarly, R1 et R2, the same, can represent an alkyl group having 10 to 15 carbon atoms, and R3 and R4 can represent an alkyl group having 6 to 10 carbon atoms.
Also, R1 and R2, R3 and R4, the same, can represent an alkyl group having 5 to 15 carbon atoms, preferably 8 to 13 carbon atoms.
Advantageously, the MoDTC compound is chosen from among the compounds of formula (A) in which:
Therefore, advantageously, the MoDTC compound can be chosen from among the compounds of formula (A1):
Advantageously, the MoDTC compound is a mixture of:
The (S/O) ratio of the number of sulfur atoms relative to the number of oxygen atoms in the MoDTC compound can generally vary from (1:3) to (3:1).
As particular examples of MoDTC compounds, mention can be made of the products Molyvan L®, Molyvan 807® or Molyvan 822® marketed by R.T Vanderbilt Company, or the products Sakuralube 200®, Sakuralube 165®, Sakuralube 525® or Sakuralube 600® marketed by Adeka.
The lubricating composition used in the invention may also be used with an organomolybdenum compound chosen from among the MoDTC compounds described in patent application WO-2012-141855.
Similarly, it can be used with a complex organomolybdenum compound or a MoDTP compound chosen from among the compounds described in patent applications WO-2014-076240 and FR-3014898.
Advantageously, the MoDTP compound is chosen from among the compounds of formula (B):
As examples of MoDTP compounds, mention can be made of the product Molyvan L® marketed by R.T Vanderbilt Company, or the products Sakura-lube 300® or Sakura-lube 310G® marketed by Adeka.
The invention can also be used with a complex organomolybdenum compound free of sulfur and phosphorus. This organomolybdenum complex free of sulfur and phosphorus can be obtained by means of ligands of amide type, chiefly prepared by reaction of a molybdenum source e.g. molybdenum trioxide with a derivative of amine and fatty acids having for example 4 to 28 carbon atoms, preferably 8 to 18 carbon atoms. Examples of fatty acids are derived from vegetable or animal oils. This organomolybdenum complex can be prepared following methods described in patents U.S. Pat. No. 4,889,647, EP-0546357, U.S. Pat. No. 5,412,130, EP-1770153. One preferred organomolybdenum complex is obtained by reaction between:
Preferably, the organomolybdenum complex comprises at least one compound of formula (D) or of formula (E), or mixture thereof:
This organomolybdenum complex can be prepared by reaction between:
More preferably, the organomolybdenum complex comprises at least one compound of formula (D1) or formula (D2), or mixture thereof:
in which Q1 is independently a saturated or unsaturated, linear or branched alkyl group having 3 to 30 carbon atoms, preferably 3 to 20 carbon atoms, advantageously 7 to 17 carbon atoms.
The lubricating composition of the invention may further comprise at least one calcium-based detergent and at least one magnesium-based detergent.
Preferably, the calcium-based detergent is chosen from among calcium salicylates, sulfonates, carboxylates, phenates, preferably salicylate.
Preferably, the magnesium-based detergent is chosen from among magnesium salicylates, sulfonates, carboxylates, phenates, preferably sulfonate.
Preferably, the lubricating composition of the invention comprises a calcium-based detergent such as to obtain from 1200 to 2000 ppm of calcium relative to the total weight of the lubricating composition and/or comprises a magnesium-based detergent such as to obtain from 0 to 600 ppm of magnesium, relative to the total weight of the lubricating composition.
The lubricating composition of the invention comprises one or more base oils. This base oil can be chosen from among numerous oils. The base oil of the lubricating composition of the invention can be chosen in particular from among oils of mineral or synthetic origin belonging to Groups I to V of the classes defined in the API classification (or equivalents thereof in the ATIEL classification) (Table A), or mixtures thereof.
Mineral base oils able to be used in the invention include all types of bases obtained by atmospheric or vacuum distillation of crude oil, followed by refining operations such as solvent extraction, deasphalting, solvent dewaxing, hydrotreatment, hydrocracking, hydroisomerization and hydrofinishing. Mixtures of synthetic and mineral oils can also be used.
There is generally no limit as to the use of different lubricants to prepare the lubricating compositions of the invention, other than that they must have properties in particular of viscosity, viscosity index, sulfur content and oxidation resistance that are adapted for use in engines.
The base oils of the lubricating compositions used in the invention may also be chosen from among synthetic oils, such as some esters of carboxylic acids and alcohols, polyalkylene glycols (PAG), and from among polyalphaolefins.
In one embodiment of the invention, the lubricating composition of the invention comprises at least one oil from Group II and/or at least one oil from Groupe III.
Typically, the base oil(s) represent at least 50% by weight, preferably at least 60% by weight, more preferably at least 70% by weight, further preferably at least 75% by weight of the total weight of the lubricating composition.
Therefore, in one embodiment, the lubricating composition comprises from 50% to 99.89% by weight, preferably from 70% to 99.5% by weight, more preferably from 80% to 99% by weight of base oil(s), preferably including at least one oil from Group II and/or at least one oil from Group Ill and/or at least one oil from Group IV and/or at least one oil from Group V.
In one particular embodiment, the lubricating composition further comprises one or more other additives.
The preferred other additives for the lubricating composition of the invention are chosen from among detergent additives, antiwear additives, friction modifying additives with the exception of molybdenum-based friction modifiers, extreme pressure additives, dispersants differing from the borated dispersants defined above, pour point improvers, viscosity index improvers, defoaming agents, thickeners and mixtures thereof.
Preferably, if any, the additives chosen from among detergent additives, antiwear additives, friction modifying additives with the exception of molybdenum-based friction modifiers, extreme pressure additives, dispersants differing from the borated dispersants defined above, pour point improvers, viscosity index improvers, defoaming agents, thickeners and mixtures thereof, represent up to 20% by weight, preferably from 0.1% to 15% by weight, more preferably from 1% to 10% by weight of the total weight of the lubricating composition.
In one embodiment, the lubricating composition further comprises at least one detergent. Detergent additives generally allow a decrease in the formation of deposits on the surface of metal parts by dissolving secondary oxidation and combustion products. The detergent additives able to be used in the lubricating composition of the invention are generally known to skilled persons. The detergent additives can be anionic compounds comprising a long lipophilic hydrocarbon chain and a hydrophilic head. The associated cation can be a metal cation of an alkali or alkaline-earth metal. The detergent additives are preferably chosen from among the alkali metal or alkaline-earth metal salts of carboxylic acids, sulfonates, salicylates, naphthenates, and phenate salts. The alkali and alkaline-earth metals are preferably calcium, magnesium, sodium, or barium. These metal salts generally comprise the metal in stoichiometric amount or else in excess, hence in an amount greater than the stoichiometric amount. In this case they are overbased detergents: the excess metal imparting the overbased nature to the detergent additive is then generally in the form of an oil-insoluble metal salt e.g. a carbonate, hydroxide, an oxalate, acetate, a glutamate, preferably a carbonate.
In one particular embodiment, the lubricating composition comprising at least one detergent is chosen from among calcium-based detergents, magnesium-based detergents, and mixture thereof. In one particular embodiment, the lubricating composition of the invention comprises at least one calcium-based detergent and at least one magnesium-based detergent.
Advantageously, the lubricating composition of the invention may comprise from 2 to 4% by weight of detergent additive(s) relative to the total weight of the lubricating composition.
Advantageously, the lubricating composition of the invention may further comprise at least one non-borated dispersing agent. The non-borated dispersing agent can be chosen from among Mannich bases, succinimides and derivatives thereof. In one embodiment, the non-borated dispersant(s) can be chosen from among non-borated polyisobutene succinimides and mixtures thereof.
Also advantageously, the lubricating composition of the invention may comprise from 0.2% to 10% by weight of non-borated dispersing agent, relative to the total weight of the lubricating composition.
The lubricating composition used in the invention may comprise at least one pour point depressant (PPD). By slowing the formation of paraffin crystals, pour point depressant agents generally provide an additional improvement in the cold start behavior of the lubricating composition used in the invention. As examples of pour point depressant agents, mention can be made of alkyl polymethacrylates (differing from the copolymer of the invention), polyacrylates (differing from the copolymer of the invention), polyarylamides, polyalkylphenols, polyalkylnaphthalenes, alkylated polystyrenes.
The lubricating composition of the invention may also comprise at least one antiwear additive, at least one extreme pressure additive or mixtures thereof. Preferably, the lubricating composition used in the invention comprises at least one antiwear additive.
Antiwear additives and extreme pressure additives protect rubbing surfaces by forming a protective film adsorbed on these surfaces. There exists a wide variety of antiwear additives. Preferably for the lubricating composition of the invention, the antiwear additives are chosen from among sulfur-phosphorus additives such as metal alkylthiophosphates in particular zinc alkylthiophosphates, and more specifically zinc dialkyldithiophosphates or ZnDTP. The preferred compounds have the formula Zn((SP(S)(ORa)(ORb))2, where Ra and Rb, the same or different, are each independently an alkyl group, preferably an alkyl group having 1 to 18 carbon atoms. Amine phosphates are also antiwear additives which can be used in the lubricating composition used in the invention. However, the phosphorus contributed by these additives can act as poison for the catalytic systems of automotive vehicles since these additives generate ash. These effects can be minimized by partially substituting the amine phosphates by additives not contributing phosphorus such as polysulfides for example, in particular sulfur-containing olefins.
Advantageously, the lubricating composition of the invention may comprise from 0.01 to 6% by weight, preferably from 0.05 to 4% by weight, more preferably from 0.1 to 2% by weight relative to the total weight of the lubricating composition of antiwear additives and extreme pressure additives.
Advantageously, the lubricating composition of the invention may comprise at least one friction modifying additive differing from the molybdenum friction modifier defined in the present invention. The friction modifying additive can be chosen from among a compound contributing metal elements and an ash-free compound. Among compounds contributing metal elements, mention can be made of complexes of transition metals such as Sb, Sn, Fe, Cu, Zn having ligands which can be hydrocarbon compounds comprising oxygen, nitrogen, sulfur or phosphorus atoms. Ash-free friction modifying additives are generally of organic origin and can be chosen from among monoesters of fatty acids and polyols, alkoxylated amines, alkoxylated fatty amines, fatty epoxides, borate fatty epoxides; fatty amines or fatty acid glycerol esters. In the invention, the fatty compounds comprise at least one hydrocarbon group having 10 to 24 carbon atoms.
Advantageously, the lubricating composition of the invention may comprise from 0.01% to 2% by weight, or from 0.01% to 5% by weight, preferably from 0.1% to 1.5% by weight or from 0.1% to 2% by weight of friction modifying additive relative to the total weight of the lubricating composition.
Advantageously, the lubricating composition of the invention may comprise at least one antioxidant additive. The antioxidant additive generally allows delayed degradation of the lubricating composition in service. This degradation can particularly translate as the formation of deposits, the presence of sludge or an increase in the viscosity of the lubricating composition. Antioxidant additives particularly act as radical inhibitors or hydroperoxide decomposers. Among antioxidant additives routinely used, mention can be made of antioxidant additives of phenolic type, antioxidant additives of amine type, sulfur-phosphorus antioxidant additives. Some of these antioxidant additives, for example those comprising sulfur and phosphorus can generate ash. Phenolic antioxidant additives can be ash-free or can be in the form of neutral or basic metal salts. The antioxidant additives can be chosen in particular from among sterically hindered phenols, sterically hindered phenol esters, and sterically hindered phenols comprising a thioether bridge, diphenylamines, diphenylamines substituted by at least one C1-C12 alkyl group, N,N′-dialkyl-aryl-diamines and mixtures thereof. Preferably, in the invention, the sterically hindered phenols are chosen from among compounds comprising a phenol group in which at least one vicinal carbon of the carbon atom carrying the alcohol function is substituted by at least one C1-C10, alkyl group, preferably a C1-C6 alkyl group, preferably a C4 alkyl group, preferably a tert-butyl group. Amine compounds are another class of antioxidant additives which can be used, optionally in combination with phenolic antioxidant additives. Examples of amine compounds are aromatic amines e.g. aromatic amines having the formula NRcRdRe in which Rc is an optionally substituted aliphatic group or aromatic group, Rd is an optionally substituted aromatic group, Re is a hydrogen atom, an alkyl group, an aryl group or a group of formula RfS(O)zRg in which Rf is an alkylene group or an alkenylene group, Rg is an alkyl group, an alkenyl group or an aryl group, and z is 0, 1 or 2. Sulfurized alkyl phenols or the alkali or alkaline-earth metal salts thereof can also be used as antioxidant additives. Another class of antioxidant additives includes copper-containing compounds, for example copper thio- or dithio-phosphates, the salts of copper and carboxylic acids, dithiocarbamates, sulfonates, phenates, copper acetylacetonates. The salts of copper I and II, the salts of succinic acid or anhydride can also be used. The lubricating composition used in the invention may contain all types of antioxidant additives known to skilled persons. Advantageously the lubricating composition comprises at least one ash-free antioxidant additive. Also advantageously, the lubricating composition used in the invention comprises from 0.5 to 2% by weight of at least one antioxidant additive relative to the total weight of the composition.
Advantageously, the lubricating composition may also comprise at least one polymer improving the viscosity index, differing from the copolymer defined in the present invention. As examples of polymer improving the viscosity index, mention can be made of polymer esters, hydrogenated or non-hydrogenated homopolymers or copolymers, styrene, butadiene and isoprene, polymethacrylates (PMA). Also advantageously, the lubricating composition of the invention may comprise from 0.1 to 15% by weight of polymer improving the viscosity index differing from the copolymer defined in the present invention, relative to the total weight of the lubricating composition.
The present invention also allows mitigated pre-ignition whilst preferably maintaining good engine cleanliness. Measurement of the pre-ignition parameter is carried out with the LSPI engine test (sequence IX, ASTMD8291).
By engine, it is preferably meant an engine of an automotive vehicle, in particular a 2-stroke or 4-stroke engine.
Preferably the use of the invention allows a lubricating composition to be obtained having a Gelation Index according to standard ASTM D5133 of less than 6, measured in particular by gradual lowering of temperature down to −40° C.
The present invention also concerns a method for improving the cold thickening properties of a lubricating composition of Grade (X)W—(Y) according to standard SAEJ 300 in which x=0, 5 or 10 and y=8, 16, 20, 30 or 40, comprising at least one base oil, comprising the addition to said lubricating composition of at least one polymer comprising repeating units able to be obtained by polymerisation of monomers (a) of formula (I):
The comb polymer, the lubricating composition are such as defined above.
The present application also concerns a lubricating composition of Grade (X)W—(Y) according to standard SAEJ 300 in which x=0, 5 or 10 and y=8, 16, 20, 30 or 40, comprising at least one base oil, a calcium-based detergent and a magnesium-based detergent and at least one polymer comprising repeating units able to be obtained by polymerisation of monomers (a) of formula (I):
The comb polymer, the lubricating composition are such as defined above.
The present application is now described and illustrated with the aid of nonlimiting examples.
The lubricating compositions (CC1 comparative compositions, CL1 to CL4 compositions of the invention), all of Grade OW-20, were prepared by mixing the compounds described in Table 2, at a temperature in the region of 60° C. The indicated percentages correspond to weight percentages relative to the total weight of the composition.
The following results were obtained after analysis of the lubricating compositions in Example 1, Tables 3 and 4.
These examples show that the addition of the comb polymer of the invention allows passing of the Gelation temperature test, i.e. the obtaining of a score of less than 6.
| Number | Date | Country | Kind |
|---|---|---|---|
| FR21 09231 | Sep 2021 | FR | national |
The present application is a U.S. National Phase Application under 35 U.S.C. § 371 of International Patent Application No. PCT/EP2022/074489 filed Sep. 2, 2022, which claims priority of French Patent Application No. 21 09231 filed Sep. 3, 2021. The entire contents of which are hereby incorporated by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/074489 | 9/2/2022 | WO |
