Lubricating composition containing ionic liquids

Abstract

The present invention relates to a lubricant composition comprising a lubricant, in particular containing a non-polar base oil, a first ionic liquid soluble in polyalphaolefin, and a second ionic liquid insoluble in polyalphaolefin. The use of the two different ionic liquids allows for improvements to the technical properties of the lubricant composition.

Description

[0001] The present invention relates to a lubricant composition containing ionic liquids and its use.

[0002] It is known that ionic liquids can be used as additives in lubricants such as greases and oils. This allows tribologically relevant properties such as friction, wear, and electrical conductivity to be favorably influenced. However, a disadvantage is that ionic liquids are either insoluble or only very sparingly soluble, particularly in lubricants that predominantly contain base oils or base oil mixtures with low polarity.

[0003] EP2164934B1 describes the use of selected ionic liquids (ILs) with fluorine-containing anions in lubricant compositions to reduce lubricant aging and electrical resistance. The ionic liquids described therein are particularly suitable for polar base oils such as esters and polyglycols. Based on this publication, it would be desirable to extend this effect to lubricants based on low-polarity base oils or base oil mixtures.

[0004] AE Somers et al., Appl. Mater. Interfaces 2013, 5, 11544–11553 (dx.doi.org / 10.1021 / am4037614) describe the use of ionic fluids as a wear-reducing additive in base oils. The study investigates the influence of the structure on miscibility and the wear-protective effect when used as a lubricant for steel on aluminum. In summary, mixtures of non-polar base oils and ILs withstood higher wear test loads than mixtures of polar base oils and ILs, with the best results achieved with mixtures of mineral oil and ILs containing the (i < C8)phosphinate cation.

[0005] US2013331305A1 describes wear- and / or friction-reducing formulations containing a mixture of at least one first ionic liquid and at least one ashless, wear-reducing compound. The ashless compound may be a second ionic liquid or an ashless thiophosphate compound. The first ionic liquid may be a monocationic or a dicationic ionic liquid. The second ionic liquid (IL) is a dicationic ionic liquid.

[0006] US20100105586A1 describes lubricating grease compositions comprising a base oil mixture based on oils with viscosities common for industrial lubricants (ISO VG 2 to ISO VG 1500), an ionic liquid, a thickener, e.g. based on a polyurea compound, and common additives, which are suitable for use at common operating temperatures from more than 120°C to 260°C, as well as at low temperatures down to -60°C.

[0007] William C. Barnhill, Huimin Luo, Harry M. Meyer III, Cheng Ma, Miaffang Chi, Brian L. Papke, Jun Qu, Tertiary and quaternary Ammonium-Phosphate Ionic Liquids as lubricant additives, Tribology letters (2016) 63:22, DOI 10.1007 / s11249-016-0707-6 describes the solubility and friction and wear properties of, for example, trioctylmethylammonium bis(2-ethylhexyl)-phosphate (abbreviation: N1888 dehp) and trioctylammonium bis(2-ethylhexyl)phosphate (N888H dehp) in a model engine oil.

[0008] EP1970432A1 describes IL with ammonium or phosphonium cations, combined with a large number of anions as additives in lubricants, especially for internal combustion engines.

[0009] US20160024421A1 describes IL with quaternary phosphonium cations, combined with branched carboxylate anions, which are said to show improved solubility in nonpolar oils.

[0010] US20150232777A1 describes IL with symmetrical phosphonium cations, combined with phosphate anions as substances and as additives for lubricants to reduce friction and wear.

[0011] The ionic liquids with phosphate and carboxylate anions mentioned in the four aforementioned documents do show improved solubility in lubricants that predominantly contain base oils with low polarity, but only a slight reduction in electrical resistance is observed.

[0012] The object of the present invention is to provide lubricant compositions that exhibit reduced electrical resistance, even when they include base oils with low polarity.

[0013] A first object of the invention is a lubricant composition comprising a) a lubricant comprising a base oil selected from the group consisting of mineral oils, polyalphaolefins, alkylated naphthalenes, alkylated diphenyl ethers, alkylated benzenes, copolymers of alkenes and mixtures thereof; b) a first ionic liquid, the anion of which is selected from the group consisting of dialkyl phosphate, dialkyl phosphinate, carboxylate and docusate and mixtures thereof; c) a second ionic liquid, the anion of which is selected from the group consisting of bis(perfluoroalkylsulfonyl)imide, tris(perfluoroalkylsulfonyl)methide, tris(perfluoroalkyl)trifluorophosphate, bisfluorosulfonylimide and mixtures thereof. wherein the first and second ionic liquids independently contain cations selected from the group of symmetrical and unsymmetrical ammonium ions NR 1 R 2 R 3 R 4 +< and phosphonium ions PR 1 R 2 R 3 R 4 +< , wherein the residues R 1 to R 4 can be independently branched or unbranched, substituted or unsubstituted C 1 - to C 24 alkyl groups, and wherein the proportion of the first ionic liquid, based on the total weight of the lubricant composition, is 0.5 to 10 wt.%, and the proportion of the second ionic liquid, based on the total weight of the lubricant composition, is 0.25 to 5 wt.%.

[0014] A preferred embodiment comprises a lubricant composition a) a lubricant containing a base oil selected from the group consisting of polyalphaolefins and alkylated diphenyl ethers and mixtures thereof, b) a first ionic liquid, the anion of which is selected from the group consisting of bis(2-ethylhexyl) phosphate, bis(2,4,4-trimethylpentyl)phosphinate, decanoate, and docusate and mixtures thereof, c) a second ionic liquid, the anion of which is selected from the group consisting of bis(perfluoroalkylsulfonyl)imide, tris(perfluoroalkylsulfonyl)methide, tris(perfluoroalkyl)trifluorophosphate, bisfluorosulfonylimide, and mixtures thereof.

[0015] A further object of the invention is the use of a lubricant composition, as defined above and below, for the treatment of surfaces of drive elements, preferably rolling bearings, gears, plain bearings and / or chains, wherein the drive elements are preferably located in plants and machines for the production and conveying of food, in wind turbines, in automobiles, in pulley bearings, in rail vehicles, in ships, in electric motors, generators, auxiliary units and / or joints.

[0016] Within the scope of the invention, the term lubricant refers to a composition comprising a base oil and optionally at least one additive. Suitable additives are defined in more detail below. Preferably, the additive is selected from corrosion inhibitors, antioxidants, agents for protection against metallic influences, radical scavengers, UV stabilizers, reaction film formers, friction inhibitors, rheology modifiers, solid lubricants, and mixtures thereof.

[0017] Suitable base oils are selected from synthetic oils, mineral oils, virgin oils, and mixtures thereof. The base oil can consist of a single base oil (in which case the terms are synonymous) or contain two or more base oils.

[0018] Preferably, the lubricant contains a non-polar base oil.

[0019] In the context of the invention, a nonpolar base oil is understood to be a base oil with a dipole moment of at most 3.00 D. The dipole moments of the base oils can be calculated according to the method described in A. Naveira Suárez, M. Grahn, R. Pasaribu and R. Larsson, The influence of base oil polarity on the tribological performance of zinc dialkyl dithiophosphate additives, Tribology International, 2010, 43 (12), pages 2268-2278.

[0020] Polyalphaolefins are commercially available and can be catalytically synthesized from ethylene using known methods, initially yielding alpha olefins with longer chain lengths as intermediates. From these, the polyalphaolefins are synthesized primarily by oligomerization, typically resulting in isoparaffins with varying numbers of side chains of equal length. The synthesis can proceed via acid-catalyzed (conventional) or metallocene-catalyzed olefin polymerization. Conventional and metallocene-catalyzed PAOs differ in their structure and the resulting product properties. Conventional PAO products exhibit a high degree of isomerization, resulting from ionic oligomerization to form charged intermediates that readily undergo carbocation rearrangements.In metallocene oligomerization, the olefin is inserted into a metal-carbon bond without the formation of charged intermediates, and the resulting products are free of isomerization. Suitable polyalphaolefins are, for example, the oligomers, preferably the dimers, trimers, tetramers, pentamers, and higher oligomers with more than five repeating units of alpha olefins, and mixtures of these oligomers. The alpha olefins used to produce the polyalphaolefins are preferably selected from C8-C14 alpha olefins, in particular 1-octene, 1-decene, 1-dodecene, and mixtures thereof. In a preferred embodiment, 1-decene- and 1-decene-containing alpha olefin mixtures are used to produce the polyalphaolefins. Technically available polyalphaolefins are generally in the form of a mixture. A typical decene dimer can consist of, for example, 80 to 99.8 wt% decene dimer, 0.1 to 19.8 wt% decene monomer, and 0.1 to 19.8 wt%-% decene trimer is included. The use of polyalphaolefin copolymers and polyalphaolefin mixtures made from alpha olefins with different numbers of carbon atoms is also possible, e.g., decene / dodecene copolymers or mixtures of decene homopolymer and dodecene homopolymer. By selecting suitable compositions of these copolymers and mixtures, the properties of the polyalphaolefins can be adjusted over a wide range depending on the specific requirements.

[0021] PAO 400 / 40, which can be used as a base oil and for determining the solubility of ionic liquids, is commercially available, e.g., under the name Synton® PAO 40 from Lanxess. PAO 400 / 40 is a polyalphaolefin with a kinematic viscosity of 40 mm² / s (= 40 cSt) at 100°C. The measurement accuracy is ±5%, and ±10% for mineral oils.

[0022] An ionic liquid is soluble in polyalphaolefin, in particular in PAO 400 / 40, made from 1-decene as the monomer component, if, in a turbidity measurement according to DIN EN ISO 7027 at 25°C, the turbidity value of a mixture of 1 wt% of the ionic liquid and 99 wt% polyalphaolefin, in particular PAO 400 / 40, made from 1-decene as the monomer component, is no more than 1 FNU higher than that of pure polyalphaolefin, in particular PAO 400 / 40, made from 1-decene as the monomer component. Polyalphaolefin was used as a reference because it is a nonpolar base oil with very low turbidity.

[0023] An ionic liquid is insoluble in polyalphaolefin, in particular in PAO 400 / 40, made from 1-decene as a monomer component, if, in a turbidity measurement according to DIN EN ISO 7027 at 25°C, the turbidity value of a mixture of 1 wt.% of the ionic liquid and 99 wt.% polyalphaolefin, in particular PAO 400 / 40 made from 1-decene as a monomer component, is more than 1 FNU higher than that of pure polyalphaolefin, in particular PAO 400 / 40, made from 1-decene as a monomer component.

[0024] Surprisingly, it was found that when a lubricant is combined with a first ionic liquid soluble in polyalphaolefin and a second ionic liquid insoluble in polyalphaolefin, the solubility of the second ionic liquid increases, and the electrical resistance of the lubricant composition is disproportionately reduced. This is particularly true for lubricant compositions containing a nonpolar base oil.

[0025] Without specifying a mechanism, it is hypothesized that in lubricant compositions containing a nonpolar base oil, the mobility of charge carriers is improved, resulting in less strong bonding of the charge carriers in the second ionic liquid due to its chemical nature. This leads to a greater reduction in electrical resistance in the nonpolar base oil when the solubility of the second ionic liquid is increased by the combination with the first. It is further hypothesized that the improved solubility of the second ionic liquid is due to an interaction with the first ionic liquid in the nonpolar base oil.

[0026] In a preferred embodiment of the invention, the first ionic liquid is soluble in the base oil, preferably nonpolar, contained in the lubricant composition, and the second ionic liquid is insoluble in this base oil. The solubility of the ionic liquid in the base oil is determined analogously to the method described in the chapter on test methods, using the base oil contained in the lubricant composition as a reference.

[0027] The increase in the solubility of the second ionic liquid was unexpected, since nonpolar base oils typically have a limited capacity to absorb ionic substances, and salting-out effects are observed when the concentration of ionic substances is increased.

[0028] Furthermore, this altered solubility behavior also has a positive effect on other lubricant properties, such as the friction and wear behavior of the lubricant composition.

[0029] According to the invention, the lubricant composition comprises a base oil as defined in the claims, preferably a non-polar base oil.

[0030] The base oil can consist of a base oil selected from synthetic oils, mineral oils, and virgin oils, or a combination of synthetic oils, mineral oils, and / or virgin oils. These oils can be used individually or in any combination, depending on the application.

[0031] Synthetic base oils include esters of an aliphatic or aromatic di-, tri-, or tetracarboxylic acid with one or more C7 to C22 alcohols present in the mixture; esters of trimethylolpropane, pentaerythritol, or dipentaerythritol with aliphatic C7 to C22 carboxylic acids; C18 dimer esters with C7 to C22 alcohols; as well as complex esters and estolides. Polyalphaolefins, also referred to here as PAOs, are also suitable base oils. These can be produced via acid catalysis or metallocene catalysis. Other suitable base oils include alkylated naphthalenes, alkylated benzenes, polyglycols, silicone oils, perfluoropolyethers, as well as polyphenyl ethers or alkylated di- or triphenyl ethers. Further synthetic base oils are copolymers of LAOs (linear alpha olefins) with unsaturated esters.

[0032] The mineral oils can be selected from paraffin-based, naphthenic, and aromatic hydrocracked oils, as well as gas-to-liquid (GTL) liquids. GTL describes a process for producing liquid hydrocarbons from natural gas. Triglycerides from animal or plant sources, refined using known processes such as hydrogenation, can be used as native oils. The preferred triglyceride oils are those with a high oleic acid content. Typical high-oleic vegetable oils used here include safflower oil, corn oil, rapeseed oil, sunflower oil, soybean oil, linseed oil, peanut oil, lessquerella oil, meadowfoam oil, and palm oil.

[0033] Preferably, the lubricant composition according to the invention comprises a lubricant containing a base oil, and the base oil comprises a first base oil selected from the group consisting of mineral oils, PAOs, alkylated diphenyl ethers and mixtures thereof, in combination with a second base oil selected from the group consisting of native and synthetic esters, polyglycols and mixtures thereof. Preferably, the weight ratio of the first base oil to the second base oil is 90:10 to 50:50, particularly preferably 85:15 to 60:40, and especially 80:20 to 70:30.

[0034] The base oil preferably comprises a base oil selected from the group consisting of mineral oils, polyalphaolefins, alkylated naphthalenes, alkylated diphenyl ethers, alkylated benzenes, copolymers of alkenes, especially linear alphaolefins (LAO) with unsaturated esters and mixtures thereof, in particular selected from the group consisting of polyalphaolefins and alkylated diphenyl ethers and mixtures thereof.

[0035] The base oil preferably comprises a base oil selected from the group consisting of copolymers of alkenes, preferably LAOs with unsaturated esters and mixtures thereof. Particularly preferably, the base oil comprises a copolymer of decene and / or dodecene and dec-9-enecarboxylic acid methyl ester, in particular Elevance Aria WTP 40 ©< , and / or mixtures thereof.

[0036] Preferred nonpolar base oils according to the invention contain a nonpolar base oil selected from the group consisting of mineral oils, polyalphaolefins, alkylated naphthalenes, alkylated diphenyl ethers, alkylated benzenes, copolymers of alkenes, in particular LAO (linear alphaolefins) with unsaturated esters, in particular a copolymer of decene and dec-9-enecarboxylic acid methyl ester, and mixtures thereof. According to the invention, preferably nonpolar base oils contain a nonpolar base oil, in particular one or more of the aforementioned nonpolar base oils, in a mixture with other base oils, in particular with polar base oils, preferably esters and polyglycols, i.e., base oils with a calculated dipole moment of over 3.00 D. The nonpolar base oil is present in a proportion of more than 50 wt.%, preferably in a proportion of more than 60 wt.%, in particular in a proportion of more than 70 wt.%, based on the total weight of the base oil.In a particular embodiment, the non-polar base oil is present in a proportion of 50 to 90 wt.%, preferably 60 to 85 wt.%, in particular 70 to 85 wt.%, based on the total weight of the base oil.

[0037] Preferably, the first ionic liquid comprises anions selected from dialkyl phosphate, dialkyl phosphinate, carboxylate, and mixtures thereof. Particularly preferably, the first ionic liquid comprises anions selected from the group consisting of bis(2-ethylhexyl) phosphate, bis(2,4,4-trimethylpentyl) phosphinate, decanoate, docusate, and mixtures thereof. Docusate refers to the anion bis(2-ethylhexyl)sulfosuccinate.

[0038] According to the invention, the second ionic liquid comprises anions selected from bis(perfluoroalkylsulfonyl)imides, tris(perfluoroalkylsulfonyl)methides, tris(perfluoroalkyl)trifluorophosphates, bis(fluorosulfonyl)imide, and mixtures thereof. In a particular embodiment, the second ionic liquid comprises anions selected from bis(perfluoroalkylsulfonyl)imides, tris(perfluoroalkylsulfonyl)methides, tris(perfluoroalkyl)trifluorophosphates, and mixtures thereof.

[0039] The second ionic liquid preferably comprises anions selected from the group consisting of bis(trifluoromethylsulfonyl)imide, tris(trifluoromethylsulfonyl)methide, tris(pentafluoroethyl)trifluorophosphate, bis(fluorosulfonyl)imide, and mixtures thereof. In a particular embodiment, the second ionic liquid comprises anions selected from the group consisting of bis(trifluoromethylsulfonyl)imide, tris(trifluoromethylsulfonyl)methide, tris(pentafluoroethyl)trifluorophosphate, and mixtures thereof. The anion bis(trifluoromethylsulfonyl)imide (bta) of the second ionic liquid is particularly preferred.

[0040] In a preferred embodiment, the second ionic liquid comprises bis(fluorosulfonyl)imide or a mixture containing bis(fluorosulfonyl)imide as the anion. In a particular embodiment, the second ionic liquid comprises bis(fluorosulfonyl)imide as the sole anion. In a further particular embodiment, the second ionic liquid comprises a mixture of bis(fluorosulfonyl)imide and at least one other anion selected from bis(perfluoroalkylsulfonyl)imides, tris(perfluoroalkylsulfonyl)methides, tris(perfluoroalkyl)trifluorophosphates, and mixtures thereof.

[0041] According to the invention, the first and second ionic liquids contain, independently of one another, cations selected from the group consisting of the respective symmetrical and unsymmetrical ammonium ions NR1R2R3R4+< and phosphonium ions PR1R2R3R4+<. The residues R1 to R4 are independently selected from among branched or unbranched, substituted or unsubstituted C1 to C24 alkyl groups. Particularly preferably, the residues R1 to R4 are independently selected from among branched or unbranched, substituted or unsubstituted C1 to C18 alkyl groups. In particular, the residues R1 to R4 are independently selected from among branched or unbranched, substituted or unsubstituted C6 to C18 alkyl groups. Preferred substituents are alkoxy, carboxy, amido, amino, thiocarboxy, carbamoyl, oxo, thioxo and / or hydroxy.

[0042] In a preferred embodiment of the invention, the residues R 1 to R 4 are selected such that they have a total of at least 10 carbon atoms, preferably at least 20 carbon atoms, and more preferably at least 25 carbon atoms.

[0043] The first ionic liquid selected from the group consisting of is particularly preferred. (Trihexyltetradecylphosphonium) bis(2-ethylhexyl)phosphate (P66614 dehp), available from IoLiTec under product number IN-0036-HP (Trihexyltetradecylphosphonium) docusate, (P66614 docusate), available from IoLiTec under product number IN-0042-HP (Trihexyltetradecylphosphonium) bis(2,4,4-trimethylpentyl)phosphinate (P66614 phosphinate) is available from IoLiTec under product number IN-0009-TG (Trihexyltetradecylphosphonium) decanoate (P66614 decanoate), available from IoLiTec under product number IN-0008-TG and their mixtures.

[0044] The second ionic liquid is particularly preferred, selected from the group consisting of (Trihexyltetradecylphosphonium) bis(trifluoromethylsulfonyl)imide (P66614 bta), available from IoLiTec under product number IN-0021-HP (Tetraoctylphosphonium) bis(trifluoromethylsulfonyl)imide (P8888 bta), available from IoLiTec under product number IN-0043-HP (Methyltrioctylammonium) bis(trifluoromethylsulfonyl)imide (N1888 bta), available from IoLiTec under product number IL-0017-HP IL-0017-HP, (Trihexyltetradecylphosphonium) bis(fluorosulfonyl)imide (P66614 fsi), available from IoLiTec. and their mixtures.

[0045] In a particular embodiment, the second ionic liquid is selected from (trihexyltetradecylphosphonium) bis(trifluoromethylsulfonyl)imide, (tetraoctylphosphonium) bis(trifluoromethylsulfonyl)imide, (methyltrioctylammonium) bis(trifluoromethylsulfonyl)imide and mixtures thereof.

[0046] Particularly preferred is the combination of (Trihexyltetradecylphosphonium) bis(2-ethylhexyl)phosphate (P66614 dehp) as the first ionic liquid with (Tetraoctylphosphonium) bis(trifluoromethylsulfonyl)imide (P8888 bta) as the second ionic liquid.

[0047] Also particularly preferred is the combination of (trihexyltetradecylphosphonium) bis(2-ethylhexyl)phosphate (P66614 dehp) as the first ionic liquid with (trihexyltetradecylphosphonium) bis(trifluoromethylsulfonyl)imide (P66614 bta) as the second ionic liquid.

[0048] Also particularly preferred is the combination of (trihexyltetradecylphosphonium) bis(2-ethylhexyl)phosphate (P66614 dehp) as the first ionic liquid with (trihexyltetradecylphosphonium) bis(fluorosulfonyl)imide (P66614 fsi) as the second ionic liquid.

[0049] In a preferred embodiment, the proportion of the first ionic liquid, based on the total weight of the lubricant composition, is 1 to 5 wt.%, in particular 2 to 5 wt.%.

[0050] In a further preferred embodiment, the proportion of the second ionic liquid, based on the total weight of the lubricant composition, is 0.5 to 2.5 wt.%, in particular 1 to 2.5 wt.%.

[0051] The weight ratio of the first ionic liquid to the second ionic liquid is preferably 1:1 to 4:1, more preferably 1.5:1 to 3:1, even more preferably 1.5:1 to 2.5:1, in particular 1.9:1 to 2.1:1.

[0052] Preferably, the proportion of the lubricant based on the total weight of the lubricant composition is 99.25 wt.% to 80 wt.%, preferably 99.25 wt.% to 85 wt.%.

[0053] Furthermore, the lubricant may contain common additives for corrosion and oxidation prevention, as well as for protection against metallic influences, such as chelating agents, radical scavengers, UV stabilizers, and reaction film formers. Additives in the form of phosphorus- and sulfur-containing compounds, e.g., zinc dialkyldithiophosphate, are preferably used as anti-wear / extreme pressure agents. Aromatic amines or substituted phenols can be used as antioxidants. Metal salts, carboxylic acids, esters, nitrogen-containing compounds, and heterocyclic compounds can be used as corrosion inhibitors, glycerol mono- or diesters as friction inhibitors, and polyisobutylene, polymethacrylate, and olefin copolymers as viscosity improvers.

[0054] The lubricant may also contain a thickening agent. This transforms the lubricant into a grease. Preferably, the thickening agent is selected from urea, aluminum complex soaps, metal simple soaps of elements from groups 1 and 2 of the periodic table, metal complex soaps of elements from groups 1 and 2 of the periodic table, bentonite, sulfonate, silicate, polyimide or PTFE, or a mixture of the aforementioned thickening agents.In the case of urea, a reaction product is meant consisting of a diisocyanate, preferably 2,4-diisocyanatotoluene, 2,6-diisocyanatotoluene, 4,4'-diisocyanatodiphenylmethane, 2,4'-diisocyantodiphenylmethane, 4,4'-diisocyanatodiphenyl, 4,4'-diisocyanato-3,3'-dimethyldiphenyl, 4,4'-diisocyanato-3,3'-dimethylphenylmethane, which can be used individually or in combination, with an amine / diamine of the general formula (H₂N) x R, where x = 1 or 2, and R is an aryl, alkyl or alkylene residue with 2 to 22 carbon atoms, which are present individually or in combination.

[0055] The lubricant may also contain inorganic or organic solid lubricants. Preferred solid lubricants are selected from the group consisting of polytetrafluoroethylene (PTFE), molybdenum disulfide, graphite, graphene, hexagonal boron nitride, tin(IV) sulfide, zinc(II) sulfide, tungsten disulfide, metal sulfides, phosphates such as calcium phosphate, carbonates such as calcium carbonate, metal oxides such as amorphous silicon dioxide, silicates and layered silicates, talc, mica, and mixtures thereof.

[0056] Another object of the present invention comprises a lubricant composition comprising a) a lubricant comprising a base oil selected from the group consisting of polyalphaolefins and alkylated diphenyl ethers and mixtures thereof, b) a first ionic liquid, the anion of which is selected from the group consisting of bis(2-ethylhexyl) phosphate, bis(2,4,4-trimethylpentyl)phosphinate, decanoate, and docusate and mixtures thereof, c) a second ionic liquid, the anion of which is selected from the group consisting of bis(perfluoroalkylsulfonyl)imide, tris(perfluoroalkylsulfonyl)methide,

[0057] Tris(perfluoroalkyl)trifluorophosphate, bisfluorosulfonylimide and their mixtures.

[0058] In a particular embodiment, the lubricant a) contains as a base oil a copolymer of alkenes selected from LAOs with unsaturated esters and mixtures thereof. In another particular embodiment, the lubricant a) contains a base oil selected from polyalphaolefins, alkylated diphenyl ethers and mixtures thereof.

[0059] In a particular embodiment, the first ionic liquid comprises b) anions selected from the group consisting of bis(2-ethylhexyl) phosphate, bis(2,4,4-trimethylpentyl)phosphinate, decanoate, docusate and mixtures thereof.

[0060] In a particular embodiment, the second ionic liquid c) comprises anions selected from the group consisting of bis(perfluoroalkylsulfonyl)imide, tris(perfluoroalkylsulfonyl)methide, tris(perfluoroalkyl)trifluorophosphate, and mixtures thereof. Bis(trifluoromethylsulfonyl)imide, tris(trifluoromethylsulfonyl)methide, tris(pentafluoroethyl)trifluorophosphate, and mixtures thereof are preferred.

[0061] With regard to the lubricant, the non-polar base oil, the first and the second ionic liquid and in particular with regard to their preferred embodiments, what has been said above and below applies mutatis mutandis.

[0062] A further object of the present invention is the use of the lubricant composition according to the invention for the treatment of surfaces of drive elements, preferably rolling bearings, gears, plain bearings and / or chains, wherein the drive elements are preferably located in plants and machines for the production and conveying of food, in wind turbines, in automobiles, in pulley bearings, in rail vehicles, in ships, in electric motors, generators, auxiliary units and / or joints.

[0063] Another object of the present invention is the use of drive elements whose surfaces have been treated with the lubricant composition according to the invention, preferably rolling bearings, gears, plain bearings and / or chains, wherein the drive elements are preferably located in plants and machines for the production and conveying of food, in wind turbines, in automobiles, in pulley bearings, in rail vehicles, in ships, in electric motors, generators, auxiliary units and / or joints.

[0064] The invention will be explained in more detail below using several examples. Examples I: Production of several lubricant compositions according to the invention and comparisons in the form of lubricating oils

[0065] To prepare the compositions according to the invention, the base oil listed in Table 1 below (copolymer of decene and dec-9-enecarboxylic acid methyl ester) was used as a nonpolar base oil. The two ionic liquids listed in the table, the second of which contains a symmetrical phosphonium cation, were added, and the mixture was stirred at 60°C for 10 minutes using a magnetic stirrer. After cooling to room temperature, the mixtures were visually inspected, and the electrical resistance was determined.

[0066] For the comparative samples, only an ionic liquid was added, but otherwise the procedure was identical. The base oil without IL was measured without further treatment. Table 1 Example P8888bta [%] (insoluble in PAO second IL) P66614dehp [%] (soluble in PAO, first IL) ARIA WTP 40 ©< [%] nonpolar base oil Specific resistance [Mohm*cm] #< Look Example 1 according to the invention 2 4 94 5,40E+01 slightly cloudy Example 2 according to the invention 1 2 97 5,89E+02 clear Example 3 Comparison 2 0 98 4,20E+03 murky Example 4 Comparison 0 4 98 3,80E+03 clear Example 5 Comparison 0,00 0,00 100,00 1,70E+06 clear #< The specific resistance is given in an exponential way, i.e., for example, the value 5.40E+01 MOhm*cm stands for 5.40*10 1< MOhm*cm.

[0067] As can be seen from Table 1, the solubility of the otherwise insoluble IL P8888bta could be increased by combining the two ILs, since examples 1 and 2 according to the invention exhibit lower turbidity compared to comparative example 3. Furthermore, examples 1 and 2 according to the invention show reduced resistance compared to comparative example 3. In addition, surprisingly, example 2 according to the invention has a lower resistance than comparative example 4, even though the ionic liquid content of example 2 according to the invention is lower than that of comparative example 4. While comparative examples 4 and 5 are clear because they do not contain any insoluble ILs, they do not solve the stated problem because they exhibit high specific resistances. Examples II: Production of several lubricant compositions according to the invention and comparative lubricant compositions in the form of lubricating oils.

[0068] To prepare the compositions according to the invention, the base oil listed in Table 2 below (copolymer of decene and dec-9-enecarboxylic acid methyl ester) was used as a nonpolar base oil. The two ionic liquids listed in the table, the second of which contains an unsymmetrical ammonium cation, were added, and the mixture was stirred at 60°C for 10 minutes using a magnetic stirrer. After cooling to room temperature, the mixtures were visually inspected, and the electrical resistance was determined.

[0069] For the comparative samples, only an ionic liquid was added, but otherwise the procedure was identical. The base oil without IL was measured without further treatment. Table 2 Example N1888 bta [%] second IL P66614dehp [%] first IL Aria WTP 40 ©< [%] Specific resistance [Mohm*cm] Look Example 6 according to the invention 2 4 94 8,02E+02 slightly cloudy Example 7 according to the invention 1 2 97 1,68E+03 slightly cloudy Example 4 Comparison 0 4 98 3,80E+03 clear Example 8 Comparison 2 0 98 3,48E+04 murky Example 5 Comparison 0 0 100 1,70E+06 clear

[0070] As can be seen from Table 2, the solubility of the otherwise insoluble IL N1888 bta could be increased by combining the two ILs, since examples 6 and 7 according to the invention exhibit lower turbidity compared to comparative example 8. Furthermore, examples 6 and 7 according to the invention show reduced resistance compared to comparative example 8. In addition, surprisingly, example 7 according to the invention exhibits lower resistance than comparative example 4, even though the ionic liquid content of example 7 according to the invention is lower than that of comparative example 4. Examples III : Production of several lubricant compositions according to the invention and comparisons in the form of lubricating greases

[0071] To produce examples 9 to 13, a fat broth was first prepared.

[0072] The composition was 93.5% Aria WTP 40 ©< 0.5% dioctyldiphenylamine (antioxidant) 6% lithium 12-hydroxystearate.

[0073] For this purpose, 30 wt% of the base oil listed in the following table (copolymer of decene and dec-9-enecarboxylic acid methyl ester; Aria WTP 40 ©<) was placed in a vessel equipped with a planetary agitator as a nonpolar base oil. 6% lithium 12-hydroxystearate was added, and the mixture was heated to 215°C while stirring. A clear melt was obtained. The heat was stopped, and 63.5 wt% of Aria WTP 40 ©< was added for cooling. At 110°C, 0.5 wt% dioctyldiphenylamine was added. The mixture was then allowed to cool to room temperature. The resulting slurry was not homogenized.

[0074] To prepare the compositions according to the invention, the two ionic liquids listed in Table 3, both of which contain an asymmetric phosphonium cation, were added to the slurry. The mixtures were blended with a spatula and homogenized twice using a three-roll mill. For the preparation of the comparative examples, only one ionic liquid was added, but the procedure was otherwise identical. Comparative example 13, without ionic liquids, was also homogenized twice using a three-roll mill. Table 3 Example P66614bta [%] P66614dehp [%] Fat broth with Aria WTP 40 ©< as non-polar base oil [%] Specific resistance [Mohm*cm] Example 9 according to the invention 2 4 96 7,10E+01 Example 10 according to the invention 1 2 97 6,78E+02 Example 11 Comparison 0 4 96 1,60E+03 Example 12 Comparison 2 0 98 1,81E+04 Example 13 Comparison 0 0 100 1,20E+06

[0075] As can be seen from Table 3, examples 9 and 10 according to the invention exhibit reduced resistance compared to comparative examples 11 to 13. Furthermore, surprisingly, example 10 according to the invention has a lower resistance than comparative example 11, even though the content of ionic liquids in example 10 according to the invention is lower than in comparative example 11.

[0076] This suggests that the results of the oil analyses can also be applied to a grease and are comparable to the measured values ​​from pure oil formulations using the same raw materials. Examples IV: Production of several lubricant compositions according to the invention and comparisons in the form of lubricating oils

[0077] To prepare the compositions according to the invention, the base oil listed in the following table, a pure hydrocarbon oil with a very low dipole moment, was used as a nonpolar base oil. The two ionic liquids listed in Table 4, both containing an asymmetric phosphonium cation, were added, and the mixture was stirred at 60°C for 10 minutes using a magnetic stirrer. For the preparation of the comparative examples, only one ionic liquid was added, but the procedure was otherwise identical. The base oil without ionic liquid was measured without further treatment.

[0078] After cooling to room temperature, the mixtures were visually inspected and the electrical resistance was determined. Table 4 Examples P66614bta [%] second IL P66614dehp [%] first IL Base oil: PAO 6 [%] Specific resistance [Mohm*cm] Look Example 14 according to the invention 0,67 5 94,33 4,65E+02 slightly cloudy Example 15 Comparison 0 5 95 9,99E+02 clear Example 16 Comparison 0,67 0 99,33 2,73E+05 clear Example 17 Comparison 0 0 100 2,20E+06 clear

[0079] As can be seen from Table 4, the example 14 according to the invention shows a reduced resistance compared to comparative examples 15 to 17. Examples V: Production of several lubricant compositions according to the invention and comparisons in the form of lubricating oils

[0080] To prepare the nonpolar base oil, base oil PAO 6 was mixed with a polar base oil, hexanedicarboxylic acid 1,6-diisotridecyl ester, at room temperature with stirring in a weight ratio of 80 wt% PAO 6 and 20 wt% hexanedicarboxylic acid 1,6-diisotridecyl ester (CAS number 26401-35-4). The two ionic liquids listed in Table 5, both containing an unsymmetrical phosphonium cation, were added to the resulting base oil, and the mixture was stirred at 60°C for 10 minutes using a magnetic stirrer. For the comparative samples, only one ionic liquid was added, but the procedure was otherwise identical. After cooling to room temperature, the mixtures were visually inspected, and the electrical resistance was determined. The base oil without ionic liquid was measured without further treatment. Table 5 Example Base oil: PAO 6 / Hexanedicarboxylic acid -1,6-diisotridecyl ester in a weight ratio of 80:20 [%] P66614dehp [%] first IL P66614bta [%] second IL specific resistance [Mohm*cm] Look Example 18 according to the invention 94 4,00 2,00 1,57E+01 clear Example 19 according to the invention 95 4,00 1,00 3,87E+01 clear Example 20 according to the invention 94 2,00 2,00 1,60E+02 slightly cloudy Example 21 according to the invention 97 2,00 1,00 1,14E+02 clear Example 22 Comparison 98 0,00 2,00 7,52E+03 murky Example 23 Comparison 99 0,00 1,00 5,62E+03 murky Example 24 Comparison 96 4,00 0,00 1,65E+03 clear Example 25 Comparison 98 2,00 0,00 1,18E+04 clear Example 26 Comparison 100 0,00 0,00 5,92E+06 clear

[0081] As can be seen from Table 5, the solubility of the otherwise insoluble IL P66614bta could be increased by combining the two ILs, since examples 18 and 21 according to the invention exhibit lower turbidity compared to comparative examples 22 and 23, respectively. Furthermore, examples 18 to 21 according to the invention show reduced resistance compared to comparative examples 23 to 26. In addition, surprisingly, example 21 according to the invention exhibits lower resistance than comparative example 24, even though the ionic liquid content of example 21 according to the invention is lower than that of comparative example 24. Examples VI: Production of several lubricant compositions according to the invention and comparisons in the form of lubricating oils

[0082] To prepare the nonpolar base oil, base oil PAO 6 was mixed with a polar base oil, hexanedicarboxylic acid 1,6-diisotridecyl ester, at room temperature with stirring in a weight ratio of 70 wt% PAO 6 and 30 wt% hexanedicarboxylic acid 1,6-diisotridecyl ester (CAS No. 26401-35-4). The two ionic liquids listed in Table 6, both containing an asymmetric phosphonium cation, were added to the resulting base oil, and the mixture was stirred at 60°C for 10 minutes using a magnetic stirrer. For the comparative samples, only one ionic liquid was added, but the procedure was otherwise identical. After cooling to room temperature, the mixtures were visually inspected, and the electrical resistance was determined. The base oil without ionic liquid was measured without further treatment. Table 6 Example Base oil: PAO 6 / Hexanedicarboxylic acid-1,6-diisotridecyl ester in a weight ratio of 70:30 P66614dehp [%] first IL P66614bta [%] second IL specific resistance [Mohm*cm] Look Example 26 according to the invention 94,00 4 2 1,05E+01 clear Example 27 according to the invention 96,00 2 2 2,24E+01 clear Example 28 according to the invention 95,00 4 1 3,29E+01 clear Example 29 according to the invention 97,00 2 1 6,62E+01 clear Example 30 Comparison 98,00 0 2 9,30E+02 murky Example 31 Comparison 96,00 4 0 1,28E+03 clear Example 32 Comparison 98,00 2 0 7,60E+03 clear Example 33 Comparison 100 0 0 4,50E+06 clear

[0083] As can be seen from Table 6, the solubility of the otherwise insoluble IL P66614bta could be increased by combining the two ILs, since examples 27 and 26 according to the invention exhibit lower turbidity compared to comparative example 30. Furthermore, examples 26 to 29 according to the invention show reduced resistance compared to comparative examples 30 to 33. In addition, surprisingly, example 29 according to the invention exhibits lower resistance than comparative example 31, even though the ionic liquid content of example 29 according to the invention is lower than that of comparative example 31. Examples VII: Production of several lubricant compositions according to the invention and comparisons in the form of lubricating oils

[0084] To prepare the compositions according to the invention, the base oil listed in Table 7 below (copolymer of decene and dec-9-enecarboxylic acid methyl ester) was used as a nonpolar base oil. The two ionic liquids listed in the table, both containing an unsymmetrical phosphonium cation, were added, and the mixture was stirred at 60°C for 10 minutes using a magnetic stirrer. After cooling to room temperature, the mixtures were visually inspected, and the electrical resistance was determined.

[0085] For the comparative samples, only an ionic liquid was added, but otherwise the procedure was identical. The base oil without IL was measured without further treatment. Table 7 Example P66614 dehp First IL [%] P66614bta Second IL [%] Aria WTP 40 ©< [%] specific resistance [Mohm*cm] Look Kinematic viscosity at 40°C Kinematic viscosity at 100°C VI Example 34 according to the invention 1,00 1,00 98,00 1,11E+03 clear 346,1 39,12 164 Example 35 according to the invention 1,50 0,50 98,00 2,50E+03 clear 348,7 35,91 165 Example 37 Comparison 0,00 2,00 98,00 1,09E+04 murky - - - Example 38 Comparison 2,00 0,00 98,00 3,00E+04 clear 348,1 39,36 164 VI = Viscosity Index

[0086] As can be seen from Table 7, all considered compositions have a total ionic liquid content of 2 wt.%. By combining the two ILs in a weight ratio of 1:1 in Example 34 and 1.5:1 in Example 35, a lower resistance was obtained than in the two comparative examples 37 and 38, which contain only one ionic liquid. However, the kinematic viscosity changes only slightly; there is no influence of viscosity on the observed differences in electrical resistance. Examples VIII: Production of several lubricant compositions according to the invention and comparisons in the form of lubricating oils

[0087] To prepare the nonpolar base oil, the base oil PAO 6 was mixed with a polar base oil, hexanedicarboxylic acid 1,6-diisotridecyl ester, at room temperature with stirring in a weight ratio of 50 wt% PAO 6 and 50 wt% hexanedicarboxylic acid 1,6-diisotridecyl ester (CAS No. 26401-35-4). The two ionic liquids listed in the table, both containing an unsymmetrical phosphonium cation, were added, and the mixture was stirred at 60°C for 10 minutes using a magnetic stirrer. After cooling to room temperature, the mixtures were visually inspected, and the electrical resistance was determined. For the comparison samples, only one ionic liquid was added, but the procedure was otherwise identical. The base oil without ionic liquid was measured without further treatment. Table 8 Example Base oil: PAO 6 / Hexanedicarboxylic acid-1,6-diisotridecyl ester in a weight ratio of 50:50 [%] P66614 dehp [%] first IL P66614 bta [%] second IL specific resistance [Mohm*cm] Look Kinematic viscosity at 40°C Kinematic viscosity at 100°C VI Example 39 according to the invention 96,00 2,00 2,00 1,09E+01 clear 29,36 5,73 140 Example 40 according to the invention 95,00 4,00 1,00 1,85E+01 clear 29,38 5,74 141 Example 41 according to the invention 97,00 2,00 1,00 3,43E+01 clear 28,54 5,62 140 Example 42 Comparison 99,00 0,00 1,00 1,31E+02 clear 27,74 5,51 140 Example 43 Comparison 96,00 4,00 0,00 8,54+02 clear 29,05 5,67 140 Example 44 Comparison 98,00 2,00 0,00 2,93E+03 clear 27,93 5,54 140 Example 45 Comparison 100,00 0,00 0,00 7,92+05 clear 27,23 5,48 140 VI = Viscosity Index

[0088] As can be seen from Table 8, examples 39 to 41 according to the invention exhibit reduced resistance compared to all comparative examples 42 to 45. Furthermore, surprisingly, example 41 according to the invention has a lower resistance than comparative example 43, even though the ionic liquid content of example 41 according to the invention is lower than that of comparative example 43. Examples 39 and 40 according to the invention exhibit the highest kinematic viscosity and the lowest specific resistance of all examples 39 to 45 at 40°C. Therefore, the observed differences in specific resistances are not attributable to changes in kinematic viscosity. Examples IX: Production of several lubricant compositions according to the invention and comparisons in the form of lubricating oils

[0089] To prepare the compositions according to the invention, the base oil listed in Table 9 below (copolymer of decene and dec-9-enecarboxylic acid methyl ester) was used as a nonpolar base oil. The two ionic liquids listed in the table, both containing an unsymmetrical phosphonium cation, were added, and the mixture was stirred at 60°C for 10 minutes using a magnetic stirrer. After cooling to room temperature, the mixtures were visually inspected, and the electrical resistance was determined.

[0090] For the comparative samples, only an ionic liquid was added, but otherwise the procedure was identical. The base oil without IL was measured without further treatment. Table 9 Example P66614fsi [%] second IL P66614dehp [%] first IL Aria WTP 40 ©< [%] Specific resistance [Mohm*cm] Look Example 46 according to the invention 2 4 94 1,76E+02 murky Example 47 according to the invention 1 2 97 5,04E+02 clear Example 48 Comparison 0 4 96 3,80E+03 clear Example 49 Comparison 2 0 98 3,39E+04 murky Example 5 Comparison 0 0 100 1,70E+06 clear

[0091] As can be seen from Table 9, examples 46 and 47 according to the invention exhibit reduced resistance compared to all comparative examples 5, 48 and 49. Furthermore, surprisingly, example 47 according to the invention has a lower resistance than comparative example 48, even though the ionic liquid content of example 47 according to the invention is lower than that of comparative example 48. Testing methods

[0092] Unless otherwise stated, the standards described refer to the version valid at the time of registration. Determination of the solubility of ionic liquids in polyalphaolefin

[0093] An ionic liquid is soluble in polyalphaolefin, in particular in PAO 400 / 40 made from 1-decene as a monomer component, if, in the turbidity measurement according to DIN EN ISO 7027 at 25°C, the turbidity value of a mixture of 1 wt.% of the ionic liquid and 99 wt.% polyalphaolefin, in particular PAO 400 / 40 made from 1-decene as a monomer component, is no more than 1 FNU higher than that of pure polyalphaolefin, in particular PAO 400 / 40 made from 1-decene as a monomer component.

[0094] An ionic liquid is insoluble in polyalphaolefin, in particular in PAO 400 / 40, made from 1-decene as a monomer component, if, in the turbidity measurement according to DIN EN ISO 7027 at 25°C, a mixture of 1 wt.% of the ionic liquid and 99 wt.% polyalphaolefin, in particular PAO 400 / 40, made from 1-decene as a monomer component, yields a turbidity value more than 1 FNU higher than that of pure polyalphaolefin, in particular PAO 400 / 40, made from 1-decene as a monomer component.

[0095] A Hach 2100 AN IS measuring instrument is used. PAO 400 / 40 is a polyalphaolefin with a mean kinematic viscosity of 400 mm² / sec at 40°C. The FNU value is below 0.2.

[0096] The ionic liquids are added to PAO 400 / 40, heated to 100°C on a magnetic stirrer while stirring, then the resulting mixture is poured into the measuring cuvettes and measured after cooling to 25°C. Synton PAO 40, made from 1-decene, was used as the PAO 400 / 40, with a kinematic viscosity at 40°C, measured according to ASTM D-445, between 38 and 42 mm² / sec. Evaluation of the appearance of lubricant compositions

[0097] To assess appearance, the lubricant compositions, in the form of lubricating oils, are carefully poured into transparent, cylindrical glass screw-top containers, 12 cm high and 1.25 cm in radius, and left undisturbed for two hours. The containers filled with lubricant compositions containing IL are compared to the container containing the corresponding non-polar base oil without IL. If a difference is observed when viewing the two samples parallel to the bottom of the container, the sample is classified as slightly cloudy or cloudy. Determination of the specific resistance of lubricating oils according to DIN 51412-1 in the version of August 1979

[0098] For the determination, a high-resistance liquid electrode FSE 3 (Fischer Elektronik, 15749 Mittenwalde, Germany) is used, and a Milli-TO 3 (Fischer Elektronik, 15749 Mittenwalde, Germany) serves as the voltage source. An average value is calculated from three individual measurements. The measuring voltage is 10 V DC. A reading is taken one minute after applying the measuring voltage. If no measurements can be obtained at 10 V, the measuring voltage is increased to 100 V, and the procedure is then repeated. This is typically required for samples with high resistivity (> 10⁴ Mohm*cm). Determination of the specific resistance of lubricating greases according to DIN 53482 (version May 1983)

[0099] For this purpose, a circular plate electrode according to section 5.3, figure 2 of the aforementioned DIN standard is modified with a 1 mm thick PTFE ring between electrode 2 and the guide piece 4. This creates a cylindrical cavity between electrode 1 (measuring electrode) and electrode 2 (counter electrode) with a height of 1 mm and an area of ​​20 mm². The cell constant is thus 200. The measured value [ohms] must be multiplied by this constant to obtain the resistivity. The lubricating grease is applied to the cavity as described above using a spatula and placed onto electrode 1. The measuring cell assembled in this way is placed in a shielded chamber (TOM 300-2, Fischer Elektronik, 15749 Mittenwalde, Germany). A Milli-TO 3 (Fischer Elektronik, 15749 Mittenwalde, Germany) is used as the voltage source. A DC voltage of 10 V is applied, and the measured value [in ohms] is read after 1 minute.The measurement is repeated three times, with fresh grease being applied to the cavity each time. The average of the three individual measurements is multiplied by the cell constant to obtain the specific resistance. If necessary, the measuring voltage can be increased as described above. Determination of the kinematic viscosity at 40°C, at 100°C and the viscosity index (VI)

[0100] Unless otherwise specified, the determination is carried out according to ASTM D7042, July 2016 edition, using a Stabinger viscometer. Determining the polarity of the base oil

[0101] The polarity of a base oil was determined according to the invention via the dipole moment. For this purpose, the dipole moments were calculated according to Trib. Int. 43, 2010, 2268 - 2278, The influence of base oil polarity on the tribological performance of zinc dialkyl dithiophosphate, AN Suarez et al., using the Hyperchem program. In the first step, the molecular structure was calculated using force field analysis ("Molecular Mechanics Force Field" with "BIO+(CHARMM)"). Subsequently, the semi-empirical model ("Semi-empirical Method") was applied with the selection "RM1". Optimizations were performed until convergence occurred (RMS gradient less than 0.01 kcal / Å mol). For base oils representing oligomeric mixtures, such as polyalphaolefins, published lead structures were used for the calculation (Exxon Mobil Chemical, in Researchgate, Harrington, BA & Reid-Peters, S. & Han, WW (2014)).The influence of molecular structure on the properties of polyalphaolefins (PAO). 61. 14-18). When the base oil is composed of different base oils, the dipole moment was summed from the mass fractions of the individual base oils and multiplied by the dipole moment calculated for each individual base oil.

[0102] The table below shows some exemplary results. Base oil calculated dipole moment [D] PAO 400 0,13 Pyromelitic acid tetra(2-ethylhexanoate) 3,35 Trimelithic acid didecyloctyl ester 3,42 PAO 6 0,09 Alkylated diphenyl ether (viscosity 100 cst at 40°C) 1,21 Pyromelithic acid tetra(2-ethylhexanoate) / alkylated diphenyl ether (weight ratio 1 : 1) 2,28 Aria WTP 40 ©< 1,82 Hexanedicarboxylic acid 1,6-diisotridecyl ester 4,79 PAO 6 / Hexanedicarboxylic acid-1,6-diisotridecyl ester (weight ratio 8 : 2) 1,03 PAO 6 / Hexanedicarboxylic acid-1,6-diisotridecyl ester (weight ratio 7 : 3) 1,50 PAO 6 / Hexanedicarboxylic acid-1,6-diisotridecyl ester (weight ratio 1 : 1) 2,44

[0103] According to the invention, a non-polar base oil is understood to be a base oil with a dipole moment of at most 3.00 D as calculated above.

Claims

1. Lubricant composition, comprising a) a lubricant containing a basic oil, selected from the group consisting of mineral oils, polyalphaolefins, alkylated naphthalenes, alkylated diphenyl ethers, alkylated benzenes, copolymers of alkenes, and mixtures thereof, b) a first ionic liquid whose anion is selected from the group consisting of dialkyl phosphate, dialkyl phosphinate, carboxylate, docusate and mixtures thereof, c) a second ionic liquid whose anion is selected from the group consisting of bis(perfluoroalkylsulfonyl)imide, tris(perfluoroalkylsulfonyl)methide, tris(perfluoroalkyl)trifluorophosphate, bis(fluorosulfonyl)imide and mixtures thereof, wherein the first and second ionic liquid independently of one another contain cations selected from the group containing symmetrical and asymmetrical ammonium ions NR1R2R3R4+ and phosphonium ions PR1R2R3R4+, wherein the radicals R1 to R4 are each independently of one another branched or unbranched, substituted or unsubstituted C1 to C24 alkyl groups, and wherein the proportion of the first ionic liquid, based on the total weight of the lubricant composition, is 0.5 to 10% by weight, and the proportion of the second ionic liquid, based on the total weight of the lubricant composition, is 0.25 to 5% by weight.

2. Lubricant composition according to claim 1, characterised in that the lubricant comprises a first base oil selected from the group consisting of mineral oils, PAO, alkylated diphenyl ethers and mixtures thereof in combination with a second base oil, selected from the group consisting of native and synthetic esters, polyglycols and mixtures thereof.

3. Lubricant composition according to claim 2, characterised in that the weight ratio of the first base oil to the second base oil is 90:10 to 50:50, more preferably 85:15 to 60:40, in particular 80:20 to 70:30.

4. Lubricant composition according to one or more of the preceding claims, characterised in that the basic oil contains a copolymer of LAO (linear alphaolefins) with unsaturated esters, in particular a copolymer of decene and dec-9-ene carboxylic acid methyl ester, and mixtures thereof.

5. Lubricant composition according to one or more of the preceding claims, characterised in that the basic oil comprises as non-polar base oil a copolymer of LAO (linear alphaolefins) with unsaturated esters, in particular a copolymer of decene and dec-9-ene carboxylic acid methyl ester and mixtures thereof in a mixture with esters and polyglycols as other base oils, wherein the non-polar base oil is in a proportion of more than 50% by weight, preferably in a proportion of more than 60% by weight, in particular in a proportion of more than 70% by weight, based on the total weight of the basic oil.

6. Lubricant composition according to one or more of the preceding claims, characterised in that the basic oil comprises a base oil, selected from the group consisting of copolymers of LAO (linear alphaolefins) with unsaturated esters, in particular a copolymer of decene and dec-9-ene carboxylic acid methyl ester.

7. Lubricant composition according to one or more of the preceding claims, characterised in that the first ionic liquid contains anions selected from the group consisting of bis(2-ethylhexyl)phosphate, bis(2,4,4-trimethylpentyl)phosphinate, decanoate and mixtures thereof.

8. Lubricant composition according to one or more of the preceding claims, characterised in that the first and second ionic liquid independently of one another contain cations selected from the group containing symmetrical and asymmetrical ammonium ions NR1R2R3R4+ and phosphonium ions PR1R2R3R4+, wherein the radicals R1 to R4 are each independently of one another branched or unbranched, substituted or unsubstituted C1 to C18 alkyl groups, more preferably C6 to C18 alkyl groups.

9. Lubricant composition according to one or more of the preceding claims, characterised in that the first ionic liquid is selected from the group consisting of - (trihexyltetradecylphosphonium) bis(2-ethylhexyl)phosphate - (trihexyltetradecylphosphonium) docusate - (trihexyltetradecylphosphonium) bis(2,4,4-trimethylpentyl)phosphinate - (trihexyltetradecylphosphonium) decanoate and mixtures thereof.

10. Lubricant composition according to one or more of the preceding claims, characterised in that the second ionic liquid is selected from the group consisting of - (trihexyltetradecylphosphonium) bis(trifluormethylsulfonyl)imide - (tetraoctylphosphonium) bis(trifluormethylsulfonyl)imide - (methyltrioctylammonium) bis(trifluormethylsulfonyl)imide - (trihexyltetradecylphosphonium) bis(fluorsulfonyl)imide and mixtures thereof.

11. Lubricant composition according to one or more of the preceding claims, characterised in that the lubricant composition comprises (trihexyltetradecylphosphonium) bis(2-ethylhexyl)phosphate as the first ionic liquid and (tetraoctylphosphonium) bis(trifluormethylsulfonyl)imide as the second ionic liquid or (trihexyltetradecylphosphonium) bis(2-ethylhexyl)phosphate as the first ionic liquid and (trihexyltetradecylphosphonium) bis(trifluormethylsulfonyl)imide as the second ionic liquid or (trihexyltetradecylphosphonium) bis(2-ethylhexyl)phosphate as the first ionic liquid and (trihexyltetradecylphosphonium) bis(fluorsulfonyl)imide as the second ionic liquid.

12. Lubricant composition according to one or more of the preceding claims, characterised in that the proportion of the first ionic liquid, based on the total weight of the lubricant composition, is 1 to 5% by weight, in particular 2 to 5% by weight and / or the proportion of the second ionic liquid, based on the total weight of the lubricant composition, is 0.5 to 2.5% by weight, in particular 1 to 2.5% by weight.

13. Lubricant composition according to one or more of the preceding claims, characterised in that the weight ratio of the first ionic liquid to the second ionic liquid is 1:1 to 4:1, preferably 1.5:1 to 3:1, more preferably 1.5:1 to 2.5:1, in particular 1.9:1 to 2.1:1.

14. Lubricant composition, containing a) a lubricant containing a basic oil, selected from the group consisting of polyalphaolefins, alkylated diphenyl ethers and mixtures thereof, b) a first ionic liquid whose anion is selected from the group consisting of bis(2-ethylhexyl) phosphate, bis(2,4,4-trimethylpentyl) phosphinate, decanoate, docusate and mixtures thereof, c) a second ionic liquid whose anion is selected from the group consisting of bis(perfluoralkylsulfonyl)imide, tris(perfluoralkylsulfonyl)methide, tris(perfluoralkyl)trifluorphosphate, bisfluorsulfonylimide and mixtures thereof.

15. Use of a lubricant composition as defined in any of claims 1 to 14 for the treatment of the surfaces of drive elements, preferably roller bearings, gears, slide bearings and / or chains, where the drive elements are preferably present in plants and machines for manufacturing and conveying food, in wind power plants, in automobiles, in pulley bearings, in rail vehicles, in ships, in electric motors, generators, auxiliary units and / or joints.

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