EP0286140B1 - Lubricant or lubricant concentrate - Google Patents

Abstract

A lubricant or lubricant concentrate based on mineral and/or synthetic oil with improved lubricating properties, in particular improved load-bearing, sliding and anticorrosion properties, contains a) one or more mineral and/or synthetic oils as the basic oil, b) at least one quadrivalent to octavalent alcohol with at least one quaternary carbon atom and at least one ether bond per molecule and having a density d20 of at least 0.900 and an enthalpy H of at least 350 kcal/kg, c) at least one asymmetric organaometallic compound, d) at least one phosphorus carrier, and e) at least one sulphur carrier, as well as f) other usual additives.

Description

The invention relates to a new lubricant or lubricant concentrate based on mineral oil and / or synthetic oil with improved lubricating properties, in particular improved load bearing, sliding and corrosion protection properties.

Over the past few decades, numerous processes and lubricant systems have been developed to reduce friction and wear on moving machine parts, thus reducing energy and spare parts costs and extending the life of the lubricants and materials. The ideal lubricant is the "Lifetime Lubricant", which also meets the ever more pressing ecological requirements.

On the way to long-term and high-performance lubricants, lubrication systems and lubrication processes, the so-called chemical wear lubrication was developed in the first stage. With their help, the application of chemically reactive cover layers to surfaces or the introduction of chemically reactive compounds in basic lubricants largely prevented metal-metal contact by salt formation on the surfaces of moving parts of the micro-mountains. This prevented the machine parts from seizing. At the same time, however, the ongoing wear was promoted by shearing off the salt layers when the metal parts moved against each other. The service life of the materials therefore remained relatively short. In a further step, solid lubricants were developed which were introduced between the moving metal parts, such as graphite, MoS₂, TiO₂, Ca₃ (PO₄) ₂, Teflon and the like, which were introduced as lubricious outer layers, suspensions, pastes or greases. Thereby the friction partners were better separated and their resilience increased. With centripetal movements of higher peripheral speed and at higher temperature, however, the solid lubricants and carrier media separate sooner or later due to their different specific densities. This limited the long-term lubrication. In a further step, it was possible to apply suitable metal cations to rubbing surfaces during operation from chemical complexes dissolved in a lubricant. Under pressure and temperature, they form the friction partners of the eutectics with the metal edge layers, which smoothly fill up the roughness valleys and partly flatten the roughness peaks tribochemically, partly microplastically. The anionic part of the organometallic compounds forms lubricating and adhesive reaction layers in situ on the freshly formed eutectoid friction surfaces

In addition to a running-in phase that is still too long, an excessively high coefficient of friction and abrasion, the control of the reaction process has proven to be problematic in these lubrication systems. Either there were material-independent eutectics and reaction layers that no longer sufficiently fine-tuned manufacturing-related material unevenness in narrow fits, so that overload areas were created at these points, which led to later metal breakouts on the sliding surfaces, or the aggressive component of the organometallic compounds was reinforced and this brought you back into the phase of chemical wear lubrication with a too high removal rate and therefore a short service life.

DE-PS 941 678, for example, discloses lubricating oils containing soluble reaction products of phosphorus pentasulfide with liquid or solid aliphatic hydrocarbons or terpene hydrocarbons. From DE-PS 923 984 a lubricating oil is known which contains metal-containing alkylphenol sulfide esters in combination with zinc sulfonates. From DE-AS 1 444 892 a lubricating oil is known which contains a salt of an aromatic zinc dithiophosphate and a zinc carboxylic acid salt in the presence of water. While the first two products are lubricating oil detergents, the latter product is intended to prevent corrosion of silver bearing surfaces. From DE-AS 1 296 730 a lubricating oil is known which contains a salt of a substituted succinic acid, optionally together with a salt of an alkylated or esterified phosphoric acid. It is an antioxidant with a detergent effect. A combination of dithiophosphate and dithiophosphinate salts is known from DE-AS 1 271 878. From DE-OS 15 94 555 cutting oils containing free sulfur, a dialkyldithiophosphate and a chlorinated hydrocarbon are known. Lubricating oils containing zinc or antimondithiocarbamate are known from US Pat. No. 3,462,367. Lubricating oils are known from US Pat. No. 2,758,087 which contain a sulfur-phosphorus compound which is obtained by reacting phosphorus pentasulfide with an olefin at a higher temperature and which contains zinc phthalate. All of these known lubricating oil additives are sufficient no longer meet today's requirements, in particular they lead to strong oxidic deposits in the area of the lubrication point and cause excessive abrasion. From US Pat. No. 2,734,865 it is known to use a lubricating oil additive which is formed from a dithiophosphate of the alkaline earth metal salts in combination with a complex reaction product of phosphorus sulfides, tall oil fatty acid alcohol esters, zinc chloride and barium hydroxide. However, the friction coefficients and abrasion values that can be achieved are too high for today's requirements, and their surface pressure value is too low. Lubricating oil additives are also known from US Pat. No. 2,734,864, which are formed from a dithiophosphate of the alkaline earth metal salts in combination with a complex reaction product of phosphorus sulfides, wool fat and alcohol esters. The undefined product contains considerable amounts of barium and zinc. Such a lubricating oil additive cannot be used in practice because of its unbearable odor, which also endangers the people who come into contact with it. From DE-PS 1 954 452, lubricants based on mineral oil or synthetic oil are known which, in addition to the mineral or synthetic oil, contain an ester of an epoxidized fatty acid having 10 to 18 carbon atoms with mono- or polyhydric alcohols, an alkyl -, Aralkyl- or aryldithiophosphate of zinc, lead, tin, tungsten, molybdenum, niobium or lanthanum and optionally contain a sulfur phosphorus compound. From DE-PS 2 108 780 lubricants based on mineral or synthetic oil or lubricant concentrates are known which in addition to a lead, tungsten, molybdenum and / or vanadium dithiophosphate esterified with alkyl, aryl or aralkyl groups, also contain at least one zinc dialkyldithiophosphate and a metal-free sulfur-phosphorus compound. These last-mentioned lubricants, which have found widespread use, no longer meet all of the requirements placed on modern long-term and high-performance lubricants. Their coefficient of friction and abrasion are too high, their shelf life is inadequate, and long-term use reveals a too high complaint rate in the area of lubrication technology

The object of the invention was therefore to create a new lubricant or lubricant concentrate based on mineral or synthetic oil, which is further improved with regard to its lubricating properties, in particular its friction and wear properties, thus noticeably reducing the need for energy and spare parts and thus also meets the highest requirements.

It has now been found that this object can surprisingly be achieved according to the invention by a lubricant or lubricant concentrate according to claim 1.

The lubricants or lubricant concentrates according to the invention have significantly improved properties compared to the known lubricants or lubricant concentrates, in particular with regard to friction and wear and thus a reduced need for energy and spare parts. It is believed that this is due to the fact that when they are used in the rubbing and sliding area, metallic glass surfaces are formed from amorphously solidified metal melts, which no longer have metal crystal lattice structures. The glass-like smooth friction and sliding surfaces, which are presumably produced with the lubricant or lubricant concentrate according to the invention, significantly improve the entire lubrication process, since the coefficient of friction and with it the abrasion, oxidation and corrosion are significantly reduced. The so-called fretting rust is also prevented by the lubricant or lubricant concentrate according to the invention. In addition, the lubricants or lubricant concentrates according to the invention are extremely environmentally friendly since they contain no lead, no sulfurized whale sperm oil and hardly any phosphorus. This has been shown by fish tests and bacterial growth tests which were carried out with the lubricants or lubricant concentrates according to the invention. It was also found that they are 60% biodegradable in normal soil within 3 to 4 months, so that they can also be described as extremely environmentally friendly. They are particularly well suited for use in comokinetic joints for vehicles, ie small joints with a high speed and a high load, and they come much closer to the "lifetime lubricant" considered to be the ideal lubricant than all previously known lubricants. In addition, the quaternary carbon atom-containing polyol ether compounds used according to the invention are thermally very stable and therefore allow high operating temperatures of up to 300 ° C. They therefore open up the possibility of lifetime lubrication of highly loaded motors, turbines, roller bearings, constant velocity joints and other high-performance machine elements.

The term "lubricant or lubricant concentrate based on mineral and / or synthetic oil" used here means both lubricating oils and lubricating greases based on mineral and / or synthetic oil.

Compounds containing quaternary carbon atoms are to be understood here as those compounds in which the four main valences of at least one carbon atom per molecule are occupied by four carbon atoms. Such compounds are mono-, di- and trimeric pentaerythritheres, other polyol ethers, pentaerythritol ethoxyethers and telomeric acid pentaerythritheres and the corresponding ethoxylated ethers.

The lubricants or lubricant concentrates according to the invention have significantly improved properties compared to the known lubricants or lubricant concentrates, as the examples below show. The glass-like smooth friction and sliding surfaces produced by the lubricant according to the invention save drive energy and lower the coefficient of friction per se and by building up a very adhesive boundary lubrication film which enables elastohydrodynamic lubrication even under point loads. As a result, the friction temperature of the lubricant and lubrication point is reduced, the oxidation resistance of both is extended and the metallic friction partners are subjected to less specific alternating loads and temperatures.
Overall, these effects greatly reduce wear and significantly increase the service life of the friction partners and the lubricant. According to the invention, these improvements are achieved within a very wide viscosity range, so that oils with low viscosity can now also be used where previously high or medium viscosity grades were considered to be absolutely necessary, for example in gearboxes, differential gearboxes or turbine reduction gearboxes. The thermal stability of the lubricant or lubricant concentrate according to the invention also allows it to be used at lubrication points at high operating temperatures, for example in diesel engines and aircraft turbines.

According to a preferred embodiment of the invention, the lubricant or lubricant concentrate contains, as component (b), mono-, di- or tripentaerythritol, the alcoholic hydroxyl group (s) of which is preferably an unbranched or branched alkyl, aralkyl or aryl group having 6 to 18 carbon atoms 6 to 12 carbon atoms, in particular 8 to 12 carbon atoms, is (are) etherified or ethoxy-etherified.

According to the invention, the lubricant or lubricant concentrate additionally contains a component with at least one free hydroxyl group.

According to a further preferred embodiment of the invention, the lubricant or lubricant concentrate according to the invention contains component (b) in an amount of 0.1 to 40% by weight, preferably 0.1 to 20% by weight, in particular 1 to 12 % By weight, especially from 2 to 6% by weight, based on the weight of the mineral and / or synthetic oil.

According to a further preferred embodiment of the invention, the lubricant or lubricant concentrate according to the invention contains as component (b) an ether and / or ethoxylated ether derivative of mono-, di- or tripentaerythritol and / or a telomeric acid pentaerythrity ether or an ethoxylated derivative thereof.

The lubricant or lubricant concentrate according to the invention preferably contains beet oil, natural oil and / or a synthetic oil with a viscosity in the range from 1.0 mPa.s at 20 ° C to 2.10⁶ mPa.s at 20 ° C. The use of a mineral oil with a viscosity is particularly preferred from 1.0 mPa.s at 20 ° C to 540 mPa.s at 50 ° C as a natural oil and the use of an aromatic or aliphatic dicarboxylic acid ester, in particular poly-α-olefin-dicarboxylic acid ester, especially butyl ester, with a molecular weight in the range of 1000 to 3000, preferably of diisocyanate phthalate, trimethyladipate and dioctyl sebacate, a polyisobutylene with a molecular weight of 1000 to 100,000 and a viscosity of 200 to 43,000 mPa.s at 100 ° C, a polymethacrylate with a. Viscosity of 1000 mPa.s at. 100 ° C, a non-water-soluble polyglycol with a \ viscosity of 5 to 60 mPa.s at 100 ° C, an isoparaffin oil and / or alkylbenzene with a flash point of over 50 ° C and a viscosity in the range of 1.0 mPa. s at 20 ° C to 2,000,000 mPa.s at 20 ° C and a telomeric acid ester, preferably a neopentyl glycol or trimethylol propane ester of telomeric acid.

As a further addition of lubricant according to the invention and lubricant concentrate preferably contains a sulfur carrier, particularly a thiazole, at least one metal dialkyldithiocarbamate and / or a metal dialkyldithiophosphate and / or a phosphor carrier, in particular a Organnophosphit, preferably a Dialkylarylphosphit, particularly didecyl or Didodecylphenylphosphit, and / or a metal dialkyldithiophosphate .

The sulfur carrier is preferably present in the lubricant or lubricant concentrate in an amount of 0.5 to 10% by weight, in particular 1 to 3% by weight, while the phosphorus carrier is preferably present in an amount of 0.1 to 10 % By weight, in particular from 0.1 to 5% by weight, especially from 0.5 to 2% by weight.

According to a preferred embodiment of the invention, the lubricant or lubricant concentrate according to the invention can contain conventional antioxidants, metal deactivators, detergents, dispersants, antifoams and / or viscosity index improvers as further conventional additives.

Further features and advantages of the invention result from the following description.

The polyol ether compounds used according to the invention with at least one quaternary carbon atom in the molecule include the following compounds:

a) ether and ethoxylated ether of mono-, di- and tripentaerythritol.

in denen die Hydroxylgruppen teilweise oder vollständig veräthert sind, deren Äthergruppen vorzugsweise gerade oder verzweigte Alkyl-, Aralkyl- oder Arylgruppen mit 6 bis 18, vorzugsweise 8 bis 12, Kohlenstoffatome darstellen.The underlying mono- and dipentaerythritol has the structure:

in which the hydroxyl groups are partially or completely etherified, the ether groups of which are preferably straight or branched alkyl, aralkyl or aryl groups having 6 to 18, preferably 8 to 12, carbon atoms.

These compounds are easy to make and numerous representatives of these compounds are commercially available.

Examples of suitable Pentaerythritäther are pentaerythritol monohexyläther, pentaerythritol monooctyläther, pentaerythritol monononyläther, pentaerythritol monodecyläther, pentaerythritol monododecyl, pentaerythritol monomyristyläther, pentaerythritol monohexadecyläther, pentaerythritol monostearyläther, pentaerythritol monooleyläther, pentaerythritol monoisostearyl- and -isopalmitinsäureäther; the corresponding dihexyl, dioctyl, dinonyl, didecyl, didodecyl, dimyristyl, dihexadecyl, distearyl, dioleyl, diisostearyl and diisopalmitic acid ether of pentaerythritol; the corresponding trihexyl, trioctyl, trinonyl, tridecyl, tridodecyl, trimyristyl, trihexadeyl, tristearyl, trioleyl, triisostearyl and triisopalmitic acid ethers of pentaerythritol, and the corresponding tetrahexyl, tetraadctyl, tetranonyl, tetranonyl , Tetradodecyl, tetramyristyl, tetrahexadecyl, tetrastearyl, tetraoleyl, tetraisostearyl and tetraisopalmitic acid ether of pentaerythritol.

b) Pentaerythrittelomeric acid derivatives with the following basic structure

worin bedeuten:
T = Telomer,
R = T oder Alkyl.

in which mean:
T = telomer,
R = T or alkyl.

As is known, telomeric acids are compounds with relatively high molecular weights and Long-chain, star-branched structures, which can be etherified in the usual way and whose ethers are valuable lubricants.

Mineral oils which can be used according to the invention are all the usual mineral oils, from isoparaffin oil with a viscosity of 1.0 mPa.s at 20 ° C to thin spindle oil with a viscosity of 12 mPa.s at 20 ° C to highly viscous bright stock and cylinder oil with a viscosity of 540 mPa .s at 50 ° C.

worin R jeweils eine geradkettige, verzweigte oder cyclische Alkylgruppe mit 6 bis 12 Kohlenstoffatomen oder in o- oder p-Stellung durch einen niederen Alkylrest mit 1 bis 6 Kohlenstoffatomen substituierte Phenylgruppe bedeuten.Many of the synthetic oils which can be used according to the invention are commercially available, for example from BP under the trade name "Hyvis 10" (a polyisobutylene with a viscosity at 100 ° C. of 200 mPa.s), "Hyvis 200" (a polyisobutylene with a viscosity of 100 ° C of 4300 mPa.s) and "Hyvis 2000" (a polyisobutylene with a viscosity at 100 ° C of 43 000 mPa.s), Viscoplex 4-95 from Röhm. (a polymethacrylate) with a viscosity of 1000 mPa.s at 100 ° C, Ucolub N9 with a viscosity of 5.7 mPa.s at 100 ° C, Ucolub N36A with a viscosity of 18 mPa.s at 100 ° C, Ucolub N 120A with a viscosity of 55 NPa.s at 100 ° C (all non-water-soluble polyglycols) from Union Carbide, and "Isopar J" from Esso (an isoparaffin oil) with a viscosity at 20 ° C of 1.0 mPa .s.
The organophosphorus compounds which can be used as phosphorus supports according to the invention are compounds of the formula

in which R in each case denotes a straight-chain, branched or cyclic alkyl group having 6 to 12 carbon atoms or phenyl group substituted in the o- or p-position by a lower alkyl radical having 1 to 6 carbon atoms.

Preferred examples of organophosphorus compounds of the above formula are monodecyl diphenyl phosphite, didecylphenyl phosphite, Triphenyl phosphite, dioctyl phenyl phosphite, dihexyl phenyl phosphite, diisodecyl phenyl phosphite, diisooctyl phenyl phosphite, didecyl-o-methylphenyl phosphite and didecyl p-methylphenyl phosphite.

worin Me ein Metall aus der Gruppe Kupfer, Silber, Zink, Cadmium, Bor, Titan, Zirkonium, Zinn, Blei, Vanadin, Tantal, Antimon, Chrom, Molybdän, Wolfram, Mangan, Kobalt und Nickel, vorzugsweise Bor, Nickel, Kobalt oder Molybdän, bedeutet.The metal dialkyldithiocarbamates which can be used according to the invention as sulfur carriers are compounds of the formula

wherein Me is a metal from the group copper, silver, zinc, cadmium, boron, titanium, zirconium, tin, lead, vanadium, tantalum, antimony, chromium, molybdenum, tungsten, manganese, cobalt and nickel, preferably boron, nickel, cobalt or Molybdenum means.

worin Me für ein Metall aus der Gruppe Kupfer, Silber, Zink, Cadmium, Bor, Titan, Zirkonium, Zinn, Blei, Vanadin, Tantal, Antimon, Chrom, Molybdän, Wolfram, Mangan, Kobalt und Nickel, vorzugsweise für Zink, Nickel, Titan, Vanadin, Molybdän, Wolfram und Mangan, steht.The metal dialkyldithiophosphates which can be used according to the invention both as a sulfur carrier and as a phosphorus carrier are compounds of the formula

wherein Me for a metal from the group copper, silver, zinc, cadmium, boron, titanium, zirconium, tin, lead, vanadium, tantalum, antimony, chromium, molybdenum, tungsten, manganese, cobalt and nickel, preferably for zinc, nickel, Titanium, vanadium, molybdenum, tungsten and manganese.

The alkyl group in the above-mentioned metal dialkyldithiocarbamate and metal dialkyldithiophosphates each preferably contain 4 to 8 carbon atoms, so that the metal salts mentioned are still soluble in the commercially available base oils. Examples of particularly advantageous alkyl groups include the diene, i- and tert-butyl group, the n- and i-amyl group, the n- and i-hexyl group, the n- and i-heptyl group and the 2-ethylhexyl group. The i-butyl group, the n- and i-amyl group and the 2-ethylhexyl group are very particularly preferred.

Examples of metal dialkyldithiocarbamates which can be used according to the invention with particular advantage are the following: copper dialkyldithiocarbamates and copper bisdialkyldithiocarbamates; Silver dialkyldithiocarbamates; Zinc and cadmium bisdialkyldithiocarbamates; Boron trisdialkyldithiocarbamate; Titanium, zirconium, tin and lead tetrakisdialkyldithiocarbamates as well as tin and lead bisdialkyldithiocarbamates; Antimony, vanadium and tantalum tris dialkyldithiocarbamates, tetrakis and pentakis dialkyldithiocarbamates and the dialkyldithiocarbamates in which these metals are present in mixed oxidation states; Chromium, chromium tris, chromium tetrakis and chromium hexakisdialkyldithiocarbamates, molybdenum and tungsten tetrakis, hexakis and oxybis and oxytetrakisdialkyl dithiocarbamates; Manganese bis, tris and hexakisdialkyldithiocarbamates; and cobalt and nickel bis and tris dialkyldithiocarbamates.

Particularly preferred among these compounds are the boron trisdialkyldithiocarbamates, the nickeltrisdialkyldithiocarbamates and the molybdenum tetrakis and molybdenum oxytetrakisdialkyldithiocarbamates.

Metal dialkyldithiophosphates which can be used with particular advantage according to the invention are the dialkyldithiophosphates of the same metals in the same oxidation states as those above for the metal dialkyldithiocarbamates have been enumerated.

Zinc bisdialkyldithiophosphates, nickel bis and tris dialkyl dithiophosphates, titanium and vanadium tetrakis dialkyl dithiophosphates, molybdenum and tungsten tetrakis dialkyl dithiophosphates and molybdenum and tungsten oxytetrakis dialkyl dithiophosphates are very particularly advantageous.

Particularly preferred representatives of the metal dialkyldithiocarbamates used according to the invention are:

Bortrisdiiosbutyldithiocarbamat, Brotrisdiamyldithiocarbamat, Bortrisdi-2-ethylhexyldithiocarbamat, Nickeltrisdiisobutyldithiocarbamat, Nickeltrisdiamyldithiocarbamat, Nickeltrisdi-2-ethylhexyldithiocarbamat, Molybdäntetrakisdi-2-ethylhexyldithiocarbamat, Molybdänoxytetrakisdi-2-ethylhexyldithiocarbamat and Kobaltbisdiisobutyldithiocarbamat.

Particularly preferred representatives of the metal dialkyldithiophosphates used in accordance with the invention are zinc bisdi-2-ethylhexyldithiophosphate, nickel bis- and trisdi-2-ethylhexyldithiophosphate, titanium and vanadium tetrakisdi-2-ethylhexyldithiophosphate as well as molybdenum and tungsten tetrakis and molybdenum oxyethyldithiophosphate.

Claims (9)

1. A lubricant and lubricant concentrate, respectively, on a mineral oil base and/or a synthetic oil base, comprising a compound having at least one quaternary carbon atom and at least one ether bond in its molecule as well as further common additives,
   characterized in that it contains

   a) at least one tetravalent to octavalent alcohol having at least one quaternary carbon atom and at least one ether bond in its molecule which compound has a density d₂₀ of at least 0,900 and an enthalpy ΔH of at least 350 kcal/kg and is selected from the group consisting of the mono-, di- and tri-pentaerythritols the alcoholic hydroxyl groups of which are etherified or ethoxyetherified by straight or branched alkyl, aralkyl or aryl groups having from 6 to 18 carbon atoms,

   b) an additional component having at least one free hydroxyl group in its molecule,

   c) at least one metal dialkyldithiocarbamate of general formula

   

   wherein

   Me   is a metal selected from the group consisting of copper, silver, zinc, cadmium, boron, titanium, zirconium, tin, lead, vanadium, tantalum, antimony, chromium, molybdenum, tungsten, manganese, cobalt and nickel, and

   Alkyl is an alkyl group having from 4 to 8 carbon atoms,

   d) at least one dialkylaryl-, monoalkyldiaryl-, trialkyl- or triarylphosphite wherein the alkyl group is straight, branched or cyclic and has from 8 to 12 carbon atoms and wherein the aryl group is a phenyl group substituted in o-or p-position by C₁-C₆-alkyl,

   e) a thiazole and

   f) antioxidants, metal deactivators, detergents, dispersants, anti-foam agents and/or viscosity index improving agents as further commonly used additives known per se.
2. The lubricant and lubricant concentrate, respectively, according to claim 1, characterized in that it comprises as a further component

   (g) at least one metal dialkyldithiophosphate of general formula

   

   wherein

   Me   is a metal selected from the group consisting of copper, silver, zinc, cadmium, boron, titanium, zirconium, tin, lead, vanadium, tantalum, antimony, chromium, molybdenum, tungsten, manganese, cobalt and nickel and

   Alkyl is an alkyl group having from 4 to 8 carbon atoms.
3. The lubricant and lubricant concentrate, respectively, according to claim 1 or 2, characterized in it contains at least one dialkyl-dithiocarbamate of boron, nickel, cobalt and molybdenum and/or at least one dialkyl-dithiophosphate of zinc, nickel, molybdenum, tungsten, titanium, vanadium and manganese.
4. The lubricant and lubricant concentrate, respectively, according to claim 3, characterized in that it contains boron tris-diisobutyl-dithiocarbamate and/or boron tris-di-2-ethylhexyl-dithiocarbamate in combination with nickel tris-diisobutyl-dithiocarbamate, nickel tris-diamyl-dithiocarbamate and/or nickel tris-di-2-ethylhexyl-dithiocarbamat as well as zinc bis-di-2-ethylhexyl-dithiophosphate, nickel tris-di-2-ethylhexyl-dithiophosphat, titanium tetrakis-di-2-ethylhexyl-dithiophosphate, vanadium tetrakis-di-2-ethylhexyl-dithiophosphate, molybdenum tetrakis- or molybdenum oxytetrakis-di-2-ethylhexyl-dithiophosphate, tungsten tetrakis- and/or tungsten oxytetrakis-di-2-ethylhexyl-dithiophosphate.
5. The lubricant and lubricant concentrate, respectively, according to any of claims 1 to 3, characterized in that it contains said component (a) in an amount of from 0,1 to 40 % by weight, preferably from 0,1 to 20 % by weight, in particular from 1 to 12 % by weight, especially from 2 to 6 % by weight, based on the weight of said mineral oil and/or said synthetic oil.
6. The lubricant and lubricant concentrate, respectively, according to any of claims 1 to 5, characterized in that it contains as said base oil a beet oil, a natural oil and/or a synthetic oil having a viscosity in the range of from 1,0 to 2.10⁶ mPa.s at 20°C.
7. The lubricant and lubricant concentrate, respectively, according to claim 6, characterized in that it contains as said natural oil a mineral oil having a viscosity of from 1,0 mPa.s at 20°C to 540 mPa.s at 50°C and/or as said synthetic oil an aromatic or aliphatic dicarboxylic acid ester, in particular a poly-α-olefin-dicarboxylic acid ester, especially -butylester, having a molecular weight in the range of from 1000 to 3000, preferably phthalic acid diisodecylester, trimethyladipic acid didecylester and sebacic acid dioctylester, a polyisobutylene having a molecular weight of from 1000 to 100 000 and a viscosity of from 200 to 43 000 mPa.s at 100°C, a polymethacrylate having a viscosity of 1000 mPa.s at 100°C, a water-insoluble polyglycol having a viscosity of from 5 to 60 mPa.s at 100°C, an isoparaffine oil and/or an alkyl benzene having an inflammation point of higher than 50°C and a viscosity in the range of from 1,0 to 2 000 000 mPa.s at 20°C.
8. The lubricant and lubricant concentrate, respectively, according to any of claims 1 to 7, characterized in that it contains said sulfur containing compound(s) in an amount of from 0,5 to 10 % by weight, preferably from 1 to 3 % by weight.
9. The lubricant and lubricant concentrate, respectively, according to any of claims 1 to 8, characterized in that it contains said phosphorus containing compound(s) in an amount of from 0,1 to 5 % by weight, preferably from 0,5 to 2 % by weight.