Patent Application
20250019615
The invention relates to a high-temperature lubricant grease including selected fluorine-free materials. The invention further relates to a process for producing the high-temperature lubricant grease and to the use thereof for lubrication of tribological systems, especially of tribological systems in applications in which a high upper use temperature is needed.
In the lubrication of tribological systems at a high upper use temperature, for example at operating temperatures above 160° C. and with no possibility of continuous relubrication, per- or polyfluorinated products with high thermal stability are typically used, for example polyfluorinated polyethers or (fluorinated) silicone oils as base oils and polytetrafluoroethylene (PTFE) micropowder as thickener.
Even in applications with food contact or drinking water contact, PTFE micropowders are often employed in practice because of their low toxicological effects as a result of chemical inertness. In principle, food-compatible lubricants are subject to legal regulations, such as NSF/H1 or NSF/H2 certification. The “H1” classification has to be achieved by lubricants for incidental food contact, i.e. occasional, technically unavoidable contact with foods. However, intentional or sustained contact also has to be ruled out in the case of use of “H1” lubricants. An “H2” classification can be achieved by lubricants that are nontoxic and noncarcinogenic. In the case of use of “H2” lubricants, nevertheless, any contact with food has to be ruled out.
PTFE is known to have excellent lubricant action as a result of very low and constant friction values even under high stresses, can effectively prevent stick-slip, and shows good stability even when used under high shear stress. In addition, it has good chemical inertness with respect to oxygen. It is thus possible to prevent the oxidation-related deposits that frequently occur in the case of lubricant greases as a result of reaction of the thickener with atmospheric oxygen, and to achieve uniform and long-lasting lubricity. There is also a high degree of reliability in lubricant operation as a result of the very favorable toxicological properties by virtue of the good chemical and thermal stability of PTFE, and even applications with unavoidable food contact can be operated therewith.
A disadvantage of the use of per- or polyfluorinated products is that they are problematic for environmental reasons.
In an embodiment, the present disclosure provides a high-temperature lubricant grease comprising
In another embodiment, the high-temperature lubricant grease is characterized in that the fluorine-free polymer has a numerical proportion of aromatic carbon atoms and/or of carbon atoms present in heteroaromatic structures of at least 20%, based on the total number of carbon atoms in the fluorine-free polymer.
In some embodiments, the high-temperature lubricant grease is characterized in that the fluorine-free material, especially the fluorine-free polymer and/or the high-temperature lubricant grease meets NSF/H1 grade.
In some embodiments, the high-temperature lubricant grease is characterized in that the fluorine-free material, especially the fluorine-free polymer, functions as thickener and the proportion of the fluorine-free material, especially the fluorine-free polymer, based on the total weight of the high-temperature lubricant grease, is 10% to 55% by weight.
In some embodiments, the high-temperature lubricant grease is characterized in that the high-temperature lubricant grease contains a further thickener other than the fluorine-free material used in accordance with the invention, preferably in a proportion of 3% by weight to 30% by weight, based on the total weight of the lubricant grease.
In some embodiments, the high-temperature lubricant grease is characterized in that the fluorine-free material, especially the fluorine-free polymer, functions as additive for lowering the friction value, where the proportion of the fluorine-free material, especially of the fluorine-free polymer, based on the total weight of the high-temperature lubricant grease, is from 1% by weight to 10% by weight.
In some embodiments, the high-temperature lubricant grease is characterized in that the high-temperature lubricant grease contains a thickener other than the fluorine-free material used in accordance with the invention, preferably in a proportion of 3% by weight to 40% by weight, based on the total weight of the lubricant grease.
In some embodiments, the high-temperature lubricant grease is characterized in that the base oil is selected from the group consisting of esters, preferably dipentaerythritol esters, trimellitic esters, hemimellitic esters, pyromellitic esters, estolides, pentaerythritol esters, dimeric acid esters, trimeric acid esters, trimethylolpropane esters (TMP esters); ethers, preferably polyphenyl ethers, diaryl ethers, triaryl ethers, polyglycols, linear or branched perfluoropolyetherols (PFPE oils); synthetic hydrocarbons, preferably alkylated naphthalenes, polyalphaolefins (PAOs), metallocene polyalphaolefins (mPAOs); untreated and chemically modified vegetable oils; group III oils; gas to liquid (GTL) oils; dimethylsilicone oils; arylated silicone oils, preferably alkyl aryl silicone oils, especially methyl/aryl silicone oils and fully arylated silicone oils, which may be used individually or in combination.
In some embodiments, the high-temperature lubricant grease is characterized in that the base oil has a kinematic viscosity, determined to ASTM-D-742 September 2014 edition, at 40° C. of 30 mm2/sec to 2000 mm2/sec, more preferably at 40° C. of 50 mm2/sec to 1200 mm2/sec, especially at 40° C. of 50 mm2/sec to 400 mm2/sec.
In another embodiment, the present disclosure provides a process for producing a high-temperature lubricant grease as claimed in one or more of the preceding claims, comprising the blending of the following components:
In some embodiments, the present disclosure provides the use of a high-temperature lubricant grease in accordance with any of the embodiments herein, where the high-temperature lubricant grease is used for lubrication of slide bearings, especially of chains or ball bearings and/or for driving of production plants in the chemical industry that are operated at least temporarily at temperatures of more than 160° C.
In some embodiments, the present disclosure provides the use of a high-temperature lubricant grease in accordance with any of the embodiments herein, where the high-temperature lubricant grease is used for lubrication of slide bearings, especially gas fittings, actuators, linear guides, closed-loop and open-loop control flaps in the intake manifold, couplings, screws, bolts, fittings, chains for the food industry, especially in bread and waffle baking machines; of ball bearings, especially ball bearings for wood pressing plants or corrugated cardboard plants and/or for driving of production plants in the chemical industry, where the slide bearings, the ball bearings and/or the production plants in the chemical industry are operated preferably at least temporarily at temperatures of above 160° C.
It is an object of the present invention to provide a high-temperature lubricant grease that can dispense with the use of PTFE and nevertheless shows low and constant friction values even under high stresses, can effectively prevent stick-slip, and has good stability even when used under high shear stress.
In addition, it should be possible to manufacture the lubricant grease to meet NSF/H1 grade.
This object is achieved by a high-temperature lubricant grease comprising
The expression “fluorine-free material” is understood in the customary manner in accordance with the invention. Thus, a fluorine-free material means materials containing no fluorine atoms in their chemical composition.
The expression “fluorine-free polymer” is likewise understood in the customary manner in accordance with the invention. Thus, a fluorine-free polymer means polymers formed from monomers that do not contain any fluorine atoms in their chemical composition.
The term “lubricant grease” is likewise understood in the customary manner in accordance with the invention. Thus, lubricant greases mean solid to semisolid materials that can be produced by dispersing a thickener into a liquid lubricant. Lubricant greases may, as well as the thickener, also contain other additives that impart particular properties to the lubricant grease. Lubricant greases are elucidated in standard ASTM D217-21, 2021.07 edition. The expression “high-temperature grease” is likewise understood in the customary manner in accordance with the invention. In particular, a high-temperature grease means a grease which, in accordance with DIN 58397-1, July 2011 edition, in the course of storage over 168 h at a test temperature of at least 160° C., has an evaporation loss of not more than 10% by weight.
It has been found that, surprisingly, the high-temperature lubricant grease of the invention makes it possible to dispense with the use of PTFE and nevertheless to achieve low and constant friction values even under high stresses, that stick-slip can be effectively prevented and good stability can be obtained even in the case of use under high shear stress.
In particular, it has been found that the fluorine-free material used in the high-temperature lubricant grease of the invention can achieve a performance equivalent to and even in some cases superior to PTFE. Thus, in practical tests, a thickener effect comparable to PTFE and friction values that are actually distinctly lower compared to PTFE were achieved, which enables another increase in energy efficiency.
In addition, it has been found that oil deposition values that are equivalent to or even distinctly lower than PTFE can be achieved, even at temperatures of 160° C. This parameter for consistent lubricants shows that the specific fluorine-free material used in accordance with the invention, compared to PTFE, can actually achieve prolonged lubricant efficacy even at high temperatures.
It is further advantageous that the high-temperature lubricant grease of the invention can be manufactured so as to meet NS/H1 grade, and that it can be used for lubrication of tribological systems in applications where a high upper use temperature is necessary.
In a preferred embodiment, the fluorine-free material is a fluorine-free polymer that has aromatic, heteroaromatic and/or heterocyclic groups and a melting point or decomposition point, measured to DIN EN ISO 11357-1, 2008.04 edition, of higher than 200° C. (option B1). The fluorine-free polymer may take the form of one substance or of a mixture of different substances, in accordance with customary understanding.
More preferably, the fluorine-free polymer has a numerical proportion of aromatic carbon atoms and/or of carbon atoms present in heteroaromatic structures of at least 20%, for example of 20% to 100%, even more preferably of at least 50%, for example of 50% to 100%, and in particular of at least 70%, for example of 70% to 100%, based in each case on the total number of carbon atoms in the fluorine-free polymer. The high proportion of aromatic carbon atoms and/or of carbon atoms present in heteroaromatic structures has a positive effect on the high-temperature stability of the lubricant grease.
In a preferred embodiment of the invention, the fluorine-free polymer has a numerical ratio of aromatic carbon atoms and/or of carbon atoms present in heteroaromatic structures to aliphatic carbon atoms of at least 1:5, more preferably of at least 1:1 and especially of at least 5:1.
Preferred heteroaromatic groups and/or heterocyclic groups independently contain nitrogen, oxygen and/or sulfur.
The aromatic, heteroaromatic and/or heterocyclic groups may also be modified with heteroatoms, especially with sulfur and/or phosphorus. The heteroatoms may be incorporated in the heteroaromatic and/or heterocyclic structure of the heteroaromatic and/or heterocyclic groups. The heteroatoms may also form a bridge across the heteroaromatic and/or heterocyclic groups and/or be present as a substituent. In addition, the heteroatoms may form a bridge across the aromatic groups and/or be present as a substituent.
More preferably in accordance with the invention, the fluorine-free polymer is selected from the group consisting of polyaryletherketone (PAEK), preferably polyetheretherketone (PEEK), even more preferably crosslinked PAEK, especially crosslinked PEEK, polyphenylsulfide (PPS), polyethersulfone (PES), poly(amide)imide (PAI), peryleneimide, polycarbonate (PC), polyquinoline, polyquinoxaline, morpholine, phthalocyanine, melamine resin and blends thereof. Likewise conceivable are copolymers of the aforementioned groups.
Likewise more preferably in accordance with the invention, the fluorine-free polymer is selected from the group consisting of polyaryletherketone (PAEK), preferably polyetheretherketone (PEEK), even more preferably crosslinked PAEK, especially crosslinked PEEK, polyphenylsulfide (PPS), polyethersulfone (PES), poly(amide)imide (PAI), peryleneimide, where peryleneimide means polymeric perylene diimide, polycarbonate (PC), polyquinoline, polyquinoxaline, polymorpholine, melamine resin and blends thereof. Likewise conceivable are copolymers of the aforementioned groups.
More preferably, the fluorine-free polymer is selected from the group consisting of polyaryletherketone (PAEK), preferably polyetheretherketone (PEEK), even more preferably crosslinked PAEK, especially crosslinked PEEK, polyphenylsulfide (PPS), melamine resin, polyethersulfone (PES), peryleneimide and blends thereof. Likewise conceivable are copolymers of the aforementioned groups.
The PAEK may, for example, be a polyetheretherketone (PEEK), a polyetherketone (PEK), a poly(etherketone-ketone) (PEKK), a poly(etheretheretherketone) (PEEEK), a poly(etherketoneetherketoneketone) (PEKEKK) or a poly(etheretherketoneketone) (PEEKK). Preference is given in accordance with the invention to PEEK.
Most preferably, the fluorine-free polymer is selected from the group consisting of polyaryletherketone (PAEK), preferably polyetheretherketone (PEEK), even more preferably crosslinked PAEK, especially crosslinked PEEK, polyphenylsulfide (PPS), melamine resin and blends thereof. Likewise conceivable are copolymers of the aforementioned groups.
Most preferably, the fluorine-free polymer is selected from the group consisting of polyaryletherketone (PAEK), preferably polyetheretherketone (PEEK), even more preferably crosslinked PAEK, especially crosslinked PEEK, polyphenylsulfide (PPS) and blends thereof. Likewise conceivable are copolymers of the aforementioned groups.
In a particularly preferred embodiment, the fluorine-free polymer is crosslinked PAEK, especially crosslinked PEEK. It has been found that crosslinked PAEK and especially crosslinked PEEK has particularly advantageous properties with regard to flexibility and thermal stability on account of its elevated glass transition range.
The crosslinked PAEK, preferably the crosslinked PEEK, is preferably obtainable from the crosslinking of PAEK, preferably of PEEK, with at least one crosslinker capable of thermal crosslinking with the keto groups of the PAEK and/or PEEK with formation of at least two imine groups per crosslinker molecule. The crosslinker is preferably selected from
The crosslinker a) is preferred.
Further preferably, the crosslinker is selected from polyamides, polyimides, aminated dimeric fatty acids, oligo-/polymers containing aminated dimeric fatty acids in copolymerized form, and mixtures thereof.
Further preferably, the crosslinker is an oligo-/polymer having at least two amide groups, where the oligo-/polymer contains monomers in copolymerized form that are selected from unsubstituted or substituted aromatic dicarboxylic acids and derivatives of unsubstituted or substituted aromatic dicarboxylic acids and aliphatic or cycloaliphatic diamines.
The aromatic dicarboxylic acids are preferably selected from respectively unsubstituted or substituted phthalic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acids or diphenyldicarboxylic acids, and the derivatives and mixtures of the aforementioned aromatic dicarboxylic acids.
The aliphatic or cycloaliphatic diamines are preferably selected from ethylenediamine, propylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, 2-methyl-1,8-octamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2-methylpentamethylenediamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 5-methylnonamethylenediamine, 2,4-dimethyloctamethylenediamine, 5-methylnonanediamine, bis(4-aminocyclohexyl) methane, 2,2-bis(4-aminocyclohexyl) propane, 1,3-bis-(aminomethyl)cyclohexane 1,4-bisaminomethylcyclo-hexane, 5-amino-2,2,4-trimethyl-1-cyclopentanemethylamine, 5-amino-1,3,3-trimethylcyclohexanemethylamine (isophoronediamine), 3,3′-dimethyl-4,4′-diamino-dicyclohexylmethane, [3-(aminomethyl)-2-bicyclo[2.2.1]heptanyl]methanamine, aminated dimeric fatty acids and mixtures thereof.
In particular, the crosslinker is selected from PA 4.T, P 5.T, PA 6.T, PA 9.T, PA8.T, PA 10.T, PA 12.T, PA 6.I, PA 8.I, PA 9.I, PA 10.I, PA 12.I, PA 6.T/6, PA 6.T/10, PA 6.T/12, PA 6.T/6.I, PA 6.T/8.T, PA 6.T/9.T, PA 6.T/10T, PA 6.T/12.T, PA 12.T/6.T, PA 6.T/6.1/6, PA 6.T/6.I/12, PA 6.T/6.1/6.10, PA 6.T/6.I/6.12, PA 6.T/6.6, PA 6.T/6.10, PA 6.T/6.12, PA 10.T/6, PA 10.T/11, PA 10.T/12, PA 8.T/6.T, PA 8.T/66, PA 8.T/8.I, PA 8.T/8.6, PA 8.T/6.I, PA 10.T/6.T, PA 10.T/6.6, PA 10.T/10.I, PA 10T/10.I/6.T, PA 10.T/6.I, PA 4.T/4.1/46, PA 4.T/4.I/6.6, PA 5.T/5.I, PA 5.T/5.I/5.6, PA 5.T/5.I/6.6, PA 6. T/6.1/6.6, PA MXDA.6, PA 6.T/IPDA.T, PA 6.T/MACM.T, PA T/PACM.T, PA 6.T/MXDA.T, PA 6.T/6.I/8.T/8.I, PA 6.T/6.1/10.T/10.1, PA 6.T/6.I/IPDA.T/IPDA.I, PA 6.T/6.I/MXDA.T/MXDA.I, PA 6.T/6.I/MACM.T/MACM.I, PA 6.T/6.I/PACM.T/PACM.I, PA 6.T/10.T/IPDA.T, PA 6.T/12.T/IPDA.T, PA 6.T/10.T/PACM.T, PA6.T/12.T/PACM.T, PA 10.T/IPDA.T, PA 12.T/IPDA.T, PA 4.6, PA 6.6, PA 6.12, PA 6.10 and copolymers and mixtures thereof.
Further preferably, the crosslinker is a saturated alicyclic compound having at least two primary amino groups, selected from aminated dimeric fatty acids, oligo-/polymers containing aminated dimeric fatty acids in copolymerized form, and mixtures thereof, especially the compound
or oligo-/polymers containing that compound in copolymerized form.
The amount of the crosslinker may be adjusted with regard to the desired degree of crosslinking. Preferably, the proportion of the crosslinker is 0.5% by weight to 20% by weight, preferably 1% by weight to 10% by weight, especially 4% by weight to 10% by weight, based in each case on the total weight of crosslinker and PAEK. It has been found that the stability of the product with such a crosslinker content can be particularly advantageous. In particular, in the case of setting of the amount of crosslinker within this range, particularly good flexibility and thermal stability can be achieved.
In a further preferred embodiment, the crosslinker is a di(aminophenyl) compound in which the two aminophenyl rings are bonded to one another via an aliphatic group having a carbocyclic radical. Most preferably, the crosslinker is a compound of the formula
According to the invention, the fluorine-free polymer has a melting point or decomposition point, measured to DIN EN ISO 11357-1, 2008.04 edition, of higher than 200° C., for example of 200° C. to 400° C., even more preferably of 220° C. to 400° C., especially of 240° C. to 400° C.
In a further preferred embodiment, the fluorine-free material is a phthalocyanine (option B1). In this case, the phthalocyanine may take the form of one substance or a mixture of different substances, in accordance with customary understanding.
In a further preferred embodiment, the fluorine-free material is a melamine derivative, preferably melamine cyanurate, melamine phosphate, especially melamine monophosphate, and/or 1,3,5-triazine-2,4,6 (1H,3H,5H)-trithione (option B2). Particular preference is given here to melamine phosphate, especially melamine monophosphate, and/or 1,3,5-triazine-2,4,6 (1H,3H,5H)-trithione. The melamine derivative and/or 1,3,5-triazine-2,4,6 (1H,3H,5H)-trithione may take the form of one substance or a mixture of different substances, in accordance with customary understanding. Lubricant greases containing these fluorine-free materials have very favorable friction value levels and, at least to some degree (especially melamine phosphate), improved antiwear properties once again by comparison with PTFE. In particular, the use of melamine phosphate in a lubricant leads to reduced shear viscosity compared to PTFE and, consequently, to elevated energy efficiency.
In a further preferred embodiment, the fluorine-free material is a mixture containing a fluorine-free polymer having aromatic, heteroaromatic and/or heterocyclic groups and a melting point or decomposition point, measured to DIN EN ISO 11357-1, 2008.04 edition, of higher than 200° C. and/or fluorine-free phthalocyanine (option B1) and a melamine derivative, especially melamine cyanurate, melamine phosphate and/or 1,3,5-triazine-2,4,6 (1H,3H,5H)-trithione (option B3).
According to the invention, the fluorine-free material has a median particle size D50 of less than 80 μm, for example of 1 μm to 80 μm, more preferably of 1 μm to 50 μm, more preferably of 1 μm to 20 μm, in particular of 1 μm to 15 μm, in each case measured to ISO 13320-1, 2020-01 edition.
The samples are preferably measured in dry form at a test pressure of 4 bar. An example of a suitable test instrument is a Malvern Mastersizer 3000.
An advantage of the use of the fluorine-free material having a median particle size of below 80 μm is that the material has very good and homogeneous distributability in the high-temperature lubricant grease, since, because this results in an elevated specific surface area (BET surface area), it has improved thickener action and can be delivered particularly efficiently to the friction site.
According to the invention, the high-temperature lubricant grease includes no polytetrafluoroethylene and/or includes polytetrafluoroethylene in a proportion of less than 6% by weight, even more preferably less than 4% by weight, even more preferably less than 2% by weight, even more preferably less than 1% by weight, even more preferably less than 0.5% by weight and in particular less than 0.1% by weight, based in each case on the total weight of the high-temperature lubricant grease. This is advantageous for environmental reasons.
In a preferred embodiment, the high-temperature lubricant grease also includes no per- or polyfluorinated products and/or includes per- or polyfluorinated products only in a proportion of less than 6% by weight, even more preferably less than 4% by weight, even more preferably less than 2% by weight, even more preferably less than 1% by weight, even more preferably less than 0.5% by weight and in particular less than 0.1% by weight, based in each case on the total weight of the high-temperature lubricant grease.
The polytetrafluoroethylene content in the high-temperature lubricant grease is preferably determined with reference to the enthalpy of fusion of PTFE using standard DIN EN ISO 11357-1, 2008.04 edition. The measurement is appropriately conducted as follows: the oil phase of the high-temperature lubricant grease including the soluble additive components is separated by extraction with a suitable solvent from solid insoluble constituents (e.g. thickener, insoluble additives and/or solid lubricants), since this increases measurement accuracy. The polytetrafluoroethylene is part of the insoluble constituents. Suitable solvents, depending on the base oil used, are in particular 80/110 special boiling point gasoline, ethanol and/or methyl perfluorobutyl ether. 80/110 special boiling point gasoline is especially suitable for lubricant greases wherein the base oil contains mineral oils, PAOs, alkylated aromatics, phenyl ethers, esters, silicone oils and polyglycols having a low ethylene oxide content, if any, and mixtures thereof. Ethanol is especially suitable for lubricant greases containing base oils composed of polyglycols having a high ethylene oxide content. Methyl perfluorobutyl ether is especially suitable for lubricant greases containing perfluoropolyethers as base oils. Lubricant greases containing two immiscible oils are preferably subjected to two extractions. Such greases are usually referred to as hybrid greases. For example, such hybrid greases may contain both perfluoropolyethers and preferably esters. Such a hybrid grease is therefore preferably extracted both with 80/110 special boiling point gasoline and with methyl perfluorobutyl ether in order to separate off both oils and the additives soluble therein. The solvent residues are drawn off from the resultant residue. The resultant dried residue is expressed relative to the amount of high-temperature lubricant grease used. The proportion of the residue is obtained in % by weight. 20 mg of the dry residue is weighed into an aluminum DSC crucible with capacity 25 μl and heated to 600° C. at a heating rate of 10 K/min. The endothermic signal between 30° and 450° C. is integrated; the area of the peak (sample enthalpy) is proportional to the amount of PTFE in the residue. For calibration, a pure PTFE micro powder (particle size D50 to ASTM D4894=5 μm, melt flow index at 372° C./2.16 kg/2.095 mm to ASTM D1238=0.5 g/10 min) is measured in an analogous manner (reference enthalpy). The PTFE content in the high-temperature lubricant grease is calculated by the following equation:
(sample enthalpy)/(reference enthalpy)*proportion of residue in % by weight=PTFE content in % by weight.
In a preferred embodiment of the invention, the fluorine-free material, especially the fluorine-free polymer and/or the high-temperature lubricant grease, meets NSF/H1 grade. The fluorine-free material, especially the fluorine-free polymer, is therefore preferably selected such that approval as a lubricant for contact with foods is possible. More preferably, all raw materials in the high-temperature lubricant grease are selected such that NSF/H1 approval is possible. This makes it possible to use the high-temperature lubricant grease of the invention in applications where it is in occasional technically unavoidable contact with foods.
According to the invention, the proportion of the fluorine-free material, based on the total weight of the high-temperature lubricant grease, is 1% by weight to 55% by weight. In a preferred embodiment, the fluorine-free material functions as thickener. The fluorine-free material may additionally function as an additive for lowering the friction value. In this embodiment, the proportion of the fluorine-free material, based on the total weight of the high-temperature lubricant grease, is preferably from 10% to 55% by weight, more preferably from 20% to 50% by weight, especially from 25% to 50% by weight.
The invention therefore provides a high-temperature lubricant grease comprising
Preferred embodiments of the aforementioned high-temperature lubricant grease embrace the preferred embodiments described in the context of the invention mutatis mutandis.
In a preferred embodiment, a high-temperature lubricant grease including the fluorine-free material as thickener includes a further thickener other than the fluorine-free material used in accordance with the invention. The further thickener is preferably selected from the group consisting of metal soaps, preferably simple metal soaps of the elements of the first and second main groups of the Periodic Table, complex metal soaps of the elements of the first and second main groups of the Periodic Table, especially lithium soap, lithium complex soaps, aluminum complex soaps, sodium complex soaps, calcium complex soaps, boron nitride, amorphous silicon dioxide, preferably aerosil, silicates, preferably bentonite, talc, mica, alkylated and/or arylated (oligo) ureas, wax, especially polyethylene (PE) wax, polypropylene (PP) wax, polyamide (PA) wax, where the wax has a melting point or decomposition point, measured to DIN EN ISO 11357-1, 2008.04 edition, of higher than 100° C.; carbon black, graphite, metal sulfonate thickeners, especially calcium sulfonate thickeners, metal chalcogenides, especially molybdenum disulfide, tungsten disulfide, metal selenides, metal phosphates, especially zinc pyrophosphate, calcium phosphate, zirconium hydrogenphosphate, which may be used individually or in combination.
In a preferred embodiment, the further thickener is an (oligo) urea, especially an alkylated and/or arylated (oligo) urea. (Oligo) ureas are reaction products of a diisocyanate, preferably 2,4-diisocyanatotoluene, 2,6-diisocyanatotoluene, 4,4′-diisocyanatodiphenylmethane, 2,4′-diisocyanatophenylmethane, 4,4′-diisocyanatodiphenyl, 4,4′-diisocyanato-3,3′-dimethylphenyl, 4,4′-diisocyanato-3,3′-dimethylphenylmethane, which may be used individually or in combination, with an amine of the general formula R′2-N—R, or a diamine of the general formula R′2-N—R—NR′2, where R is an aryl, alkyl or alkylene radical having 2 to 22 carbon atoms and R′ is identical or different and is a hydrogen, an alkyl, alkylene or aryl radical, or with mixtures of amines and diamines.
In a further preferred embodiment, the further thickener is a calcium sulfonate thickener. Calcium sulfonate thickeners contain crystalline calcium carbonate in the form of calcite and calcium salts of acids, especially aromatic sulfonic acids, most preferably alkylbenzenesulfonic acids, carboxylic acids, especially stearic acid, 12-hydroxystearic acid, acetic acid, boric acid and mixtures thereof.
In a further preferred embodiment, the further thickener is a metal soap, especially a lithium soap and/or a lithium complex soap. A lithium soap means lithium salts of monofunctional carboxylic acids. Particular preference is given to lithium salts of monofunctional carboxylic acids having 8 to 22 carbon atoms, more preferably 14 to 20 carbon atoms. Particularly preferred lithium soaps are lithium salts of stearic acid, hydroxystearic acid, 12-hydroxystearic acid, monohydroxybenzoic acid, especially salicylic acid, and/or lithium salts of mixtures of the aforementioned acids.
A lithium complex soap means mixtures of lithium salts of monofunctional carboxylic acids with lithium salts of dicarboxylic acids and/or tricarboxylic acids. The lithium complex soap preferably includes lithium salts of monofunctional carboxylic acids having 8 to 22 carbon atoms, more preferably 14 to 20 carbon atoms. More preferably, the lithium complex soap includes lithium salts of stearic acid, hydroxystearic acid, 12-hydroxystearic acid, monohydroxybenzoic acid, especially salicylic acid, and/or lithium salts of mixtures of the aforementioned acids. Likewise more preferably, the lithium complex soap includes lithium salts of dicarboxylic acids having 2 to 20 carbon atoms, more preferably 8 to 12 carbon atoms. Most preferably, the lithium complex soap includes lithium salts of azelaic acid, sebacic acid, dodecanedioic acid and/or lithium salts of mixtures of the aforementioned acids. In addition, the lithium complex soap may include further components, for example lithium salts of short-chain carboxylic acids such as acetic acid and lactic acid and/or phosphorus-containing acids and/or boric acid.
In a further preferred embodiment, the further thickener is a combination of two or more of the aforementioned further thickeners.
If used, the proportion of the further thickener is preferably from 3% by weight to 30% by weight, more preferably from 3% by weight to 20% by weight and in particular from 3% by weight to 10% by weight, based in each case on the total weight of the lubricant grease.
In a further preferred embodiment, the fluorine-free material functions as an additive for lowering the friction value. The material, depending on the amount present, may additionally function as a thickener. In this embodiment, the proportion of the fluorine-free material, based on the total weight of the high-temperature lubricant grease, is preferably from 1% by weight to 10% by weight, more preferably from 5% by weight to 7% by weight, especially from 1% by weight to 5% by weight.
In this embodiment, in which the fluorine-free material functions as additive for lowering the friction value, the high-temperature lubricant grease preferably includes a thickener other than the fluorine-free material used in accordance with the invention. The thickener is preferably selected from the group consisting of metal soaps, preferably simple metal soaps of the elements of the first and second main groups of the Periodic Table, complex metal soaps of the elements of the first and second main groups of the Periodic Table, especially lithium soap, lithium complex soaps, aluminum complex soaps, sodium complex soaps, calcium complex soaps, boron nitride, amorphous silicon dioxide, preferably aerosil, silicates, preferably bentonite, talc, mica, alkylated and/or arylated (oligo) ureas, wax, especially polyethylene (PE) wax, polypropylene (PP) wax, polyamide (PA) wax, where the wax has a melting point or decomposition point, measured to DIN EN ISO 11357-1, 2008.04 edition, of higher than 100° C.; carbon black, graphite, metal sulfonate thickeners, especially calcium sulfate thickeners, metal chalcogenides, especially molybdenum disulfide, tungsten disulfide, metal selenides, metal phosphates, especially zinc pyrophosphate, calcium phosphate, zirconium hydrogenphosphate, which may be used individually or in combination.
(Oligo) ureas are reaction products of a diisocyanate, preferably 2,4-diisocyanatotoluene, 2,6-diisocyanatotoluene, 4,4′-diisocyanatodiphenylmethane, 2,4′-diisocyanatophenylmethane, 4,4′-diisocyanatodiphenyl, 4,4′-diisocyanato-3,3′-dimethylphenyl, 4,4′-diisocyanato-3,3′-dimethylphenylmethane, which may be used individually or in combination, with an amine of the general formula R′2-N—R, or a diamine of the general formula R′2-N—R—NR′2, where R is an aryl, alkyl or alkylene radical having 2 to 22 carbon atoms and R′ is identical or different and is a hydrogen, an alkyl, alkylene or aryl radical, or with mixtures of amines and diamines.
In a further preferred embodiment, the thickener is a calcium sulfonate thickener. Calcium sulfonate thickeners contain crystalline calcium carbonate in the form of calcite and calcium salts of acids, especially aromatic sulfonic acids, most preferably alkylbenzenesulfonic acids, carboxylic acids, especially stearic acid, 12-hydroxystearic acid, acetic acid, boric acid and mixtures thereof.
In a further preferred embodiment, the thickener is a metal soap, especially a lithium soap and/or a lithium complex soap. A lithium soap means lithium salts of monofunctional carboxylic acids. Particular preference is given to lithium salts of monofunctional carboxylic acids having 8 to 22 carbon atoms, more preferably 14 to 20 carbon atoms. Particularly preferred lithium soaps are lithium salts of stearic acid, hydroxystearic acid, 12-hydroxystearic acid, monohydroxybenzoic acid, especially salicylic acid, and/or lithium salts of mixtures of the aforementioned acids.
A lithium complex soap means mixtures of lithium salts of monofunctional carboxylic acids with lithium salts of dicarboxylic acids and/or tricarboxylic acids. The lithium complex soap preferably includes lithium salts of monofunctional carboxylic acids having 8 to 22 carbon atoms, more preferably 14 to 20 carbon atoms. More preferably, the lithium complex soap includes lithium salts of stearic acid, hydroxystearic acid, 12-hydroxystearic acid, monohydroxybenzoic acid, especially salicylic acid, and/or lithium salts of mixtures of the aforementioned acids. Likewise more preferably, the lithium complex soap includes lithium salts of dicarboxylic acids having 2 to 20 carbon atoms, more preferably 8 to 12 carbon atoms. Most preferably, the lithium complex soap includes lithium salts of azelaic acid, sebacic acid, dodecanedioic acid and/or lithium salts of mixtures of the aforementioned acids. In addition, the lithium complex soap may include further components, for example lithium salts of short-chain carboxylic acids such as acetic acid and lactic acid and/or phosphorus-containing acids and/or boric acid.
In a further preferred embodiment, the thickener is a combination of two or more of the aforementioned further thickeners.
The thickener is preferably a metal soap. Preferred metal soaps are the metal soaps described above in relation to the further thickener.
The proportion of the thickener is preferably from 3% by weight of 40% by weight, more preferably from 6% by weight to 30% by weight and in particular from 8% by weight to 25% by weight, based in each case on the total weight of the lubricant grease.
The invention therefore provides a high-temperature lubricant grease comprising
Preferred embodiments of the aforementioned high-temperature lubricant grease embrace the embodiments described in the context of the invention mutatis mutandis.
It has been found that particularly consistent lubricants can be obtained with the preferred amounts of fluorine-free material, which are comparable to the amounts customarily used in the case of PTFE.
According to the invention, the high-temperature lubricant grease includes 20% to 88% by weight, preferably 30% by weight to 88% by weight, more preferably 50% by weight to 88%, especially 60% by weight to 88% by weight, of a base oil, based in each case on the total weight of the high-temperature lubricant grease.
The base oil is preferably selected from the group consisting of esters, preferably dipentaerythritol esters, trimellitic esters, hemimellitic esters, pyromellitic esters, estolides, pentaerythritol esters, dimeric acid esters, trimeric acid esters, trimethylolpropane esters (TMP esters); ethers, preferably polyphenyl ethers, diaryl ethers, triaryl ethers, polyglycols, linear or branched perfluoropolyetherols (PFPE oils); synthetic hydrocarbons, preferably alkylated naphthalenes, polyalphaolefins (PAOs), metallocene polyalphaolefins (mPAOs); untreated and chemically modified vegetable oils; group III oils; gas to liquid (GTL) oils; dimethylsilicone oils; arylated silicone oils, preferably alkyl aryl silicone oils, especially methyl/aryl silicone oils and fully arylated silicone oils, which may be used individually or in combination.
Further preferably, the base oil is selected from the group consisting of dipentaerythritol esters, trimellitic esters, hemimellitic esters, pyromellitic esters, estolides, pentaerythritol esters, dimeric acid esters, trimeric acid esters, trimethylolpropane esters (TMP esters); polyphenyl ethers, diaryl ethers, triaryl ethers, polyglycols, linear or branched perfluoropolyetherols (PFPE oils); alkylated naphthalenes, metallocene polyalphaolefins (mPAOs); untreated and chemically modified vegetable oils; group III oils; gas to liquid (GTL) oils; dimethylsilicone oils; arylated silicone oils, preferably alkyl aryl silicone oils, especially methyl/aryl silicone oils and fully arylated silicone oils, which may be used individually or in combination.
In a preferred embodiment of the invention, the base oil is selected from the group consisting of esters, preferably dipentaerythritol esters, trimellitic esters, hemimellitic esters, pyromellitic esters, estolides, pentaerythritol esters, dimeric acid esters, trimeric acid esters; ethers, preferably polyphenyl ethers, diaryl ethers, triaryl ethers, linear or branched perfluoropolyetherols (PFPE oils); synthetic hydrocarbons, preferably alkylated naphthalenes, polyalphaolefins (PAOs), metallocene polyalphaolefins (mPAOs); group III oils; arylated silicone oils, preferably alkyl aryl silicone oils, especially methyl/aryl silicone oils and fully arylated silicone oils, which may be used individually or in combination.
In a further preferred embodiment of the invention, the base oil is a fluorine-free base oil, preferably selected from the group consisting of dipentaerythritol esters, trimellitic esters, hemimellitic esters, pyromellitic esters, estolides, pentaerythritol esters, dimeric acid esters, trimeric acid esters; polyphenyl ethers, diaryl ethers, triaryl ethers; synthetic hydrocarbons, preferably alkylated naphthalenes, polyalphaolefins (PAOs), metallocene polyalphaolefins (mPAOs); arylated silicone oils, preferably alkyl aryl silicone oils, especially methyl/aryl silicone oils and fully arylated silicone oils, which may be used individually or in combination.
Further preferably, the base oil is selected from the group consisting of linear or branched perfluoropolyetherols (PFPE oils), preferably branched perfluoropolyetherols (PFPE oils), polyalphaolefins (PAOs) and mixtures thereof.
In a further preferred embodiment, the base oil has a kinematic viscosity, determined to ASTM D-742 September 2014 edition, at 40° C. of 30 mm2/sec to 2000 mm2/sec, more preferably at 40° C. of 50 mm2/sec to 1200 mm2/sec, especially at 40° C. of 50 mm2/sec to 400 mm2/sec.
In a likewise preferred embodiment of the invention, the base oil is selected from the group consisting of esters, preferably dipentaerythritol esters, trimellitic esters, hemimellitic esters, pyromellitic esters, estolides, pentaerythritol esters, dimeric acid esters, trimeric acid esters, each with a kinematic viscosity determined at 40° C. to ASTM D-742 September 2014 edition, of 50 mm2/sec to 1200 mm2/sec; ethers, preferably polyphenyl ethers, diaryl ethers, triaryl ethers, linear or branched perfluoropolyetherols (PFPE oils), each with a kinematic viscosity determined at 40° C. to ASTM D-742 September 2014 edition, of 30 mm2/sec to 1200 mm2/sec; synthetic hydrocarbons, preferably alkylated naphthalenes, polyalphaolefins (PAOs), metallocene polyalphaolefins (mPAOs), each with a kinematic viscosity determined at 40° C. to ASTM D-742 September 2014 edition, of 30 mm2/sec to 20 000 mm2/sec; group III oils, arylated silicone oils, preferably alkyl aryl silicone oils, especially methyl/aryl silicone oils and fully arylated silicone oils, each with a kinematic viscosity determined at 40° C. to ASTM D-742 September 2014 edition, of 30 mm2/sec to 1200 mm2/sec and/or each with a kinematic viscosity determined at 25° C. to DIN 53019, 2008.09 edition, of 30 to 2 000 000 mm2/sec, which may be used individually or in combination.
In a preferred embodiment of the invention, the high-temperature lubricant grease includes additives to counteract wear, oxidation, corrosion, additives to reduce friction, additives to improve high-pressure properties, pour point and/or viscosity.
If used, the additives are preferably present in a proportion of 1% by weight to 10% by weight, more preferably from 1% by weight to 8% by weight and especially from 1% by weight to 5% by weight, based in each case on the total weight of the high-temperature lubricant grease.
Antioxidants used are especially antioxidants selected from the group consisting of aromatic aminic antioxidants, such as alkylated phenyl-alpha-naphthylamine, dialkyldiphenylamine, aralkylated diphenylamine, sterically hindered phenols, such as butylhydroxytoluene (BHT), which may be used individually or in combination.
The antiwear agent is preferably selected from the group consisting of amine-neutralized phosphates, alkylated and nonalkylated triaryl phosphates, alkylated and nonalkylated triaryl thiophosphates, zinc dialkyldithiophosphates, molybdenum dialkyldithiophosphates or tungsten dialkyldithiophosphates, carbamates, thiocarbamates, zinc dithiocarbamates, molybdenum dithiocarbamates or tungsten dithiocarbamates, dimercaptothiadiazole, which may be used individually or in combination.
The anticorrosion agent is preferably selected from the group consisting of additives based on calcium sulfonates, preferably overbased calcium sulfonates having a base number (TBN) of 100 to 500 mg KOH/g, amine-neutralized phosphates, alkylated calcium naphthalene-sulfonates, oxazoline derivatives, imidazole derivatives, succinic monoesters, N-alkylated benzotriazoles, benzotriazole, which may be used individually or in combination.
Preferred high-pressure additives are selected from the group consisting of thiophosphates, sulfated compounds, preferably sulfated fatty acid esters, alkylated polysulfides, which may be used individually or in combination.
Preferred additives for improving the pour point and/or viscosity are selected from the group consisting of linear or branched, alkylated, acrylated and/or aliphatic polymers, copolymers, which may be used individually or in combination.
In a preferred embodiment, the high-temperature lubricant grease has a worked penetration measured to DIN ISO 2137, December 2016 edition, of 200 1/10 mm to 400 1/10 mm, preferably of 220 1/10 mm to 340 1/10 mm, more preferably of 250 to 340 1/10 mm, in particular of 265 1/10 mm to 295 1/10 mm.
The lubricant grease is preferably a consistent lubricant grease. In a further preferred embodiment, the high-temperature lubricant grease is a lubricant grease of NLGI class 1 to 3, preferably 2, according to DIN 51818, 1981.12 edition.
The invention also relates to a process for producing the high-temperature lubricant grease, comprising the blending of the following components:
Preferred embodiments of the aforementioned process embrace the embodiments described in the context of the invention in relation to the high-temperature grease of the invention mutatis mutandis.
The invention further relates to the use of the high-temperature lubricant grease of the invention for lubrication of tribological systems, especially of tribological systems in applications where a high upper use temperature of preferably above 160° C., more preferably above 180° C., especially above 200° C., is necessary.
In a preferred embodiment of the invention, the high-temperature lubricant grease of the invention is used for lubrication of slide bearings, especially of chains, ball bearings and/or for driving of production plants in the chemical industry that are operated at least temporarily at temperatures of above 160° C., more preferably above 180° C., especially above 200° C.
In a particularly preferred embodiment of the invention, the high-temperature lubricant grease of the invention is designed as a high-temperature grease for ball bearing applications. A high-temperature grease for ball bearing applications is understood here to mean a grease which, in accordance with DIN 51825:2004-06 at 3000 rpm, a load of 1500 N and installation position B, reaches its upper use temperature at at least 160° C., for example from 160° C. to 240° C., and/or at 160° C. to 200° C. The upper use temperature has been attained when at least 50% of a collective of bearings (at least 5 test bearings) reaches a service life of at least 100 h at the test temperature.
A preferred embodiment of the invention encompasses the use of the high-temperature lubricant grease of the invention for lubrication of slide bearings, especially gas fittings, actuators, linear guides, closed-loop and open-loop control flaps in the intake manifold, couplings, screws, bolts, fittings, chains for the food industry, especially in bread and waffle baking machines; of ball bearings, especially ball bearings for wood pressing plants or corrugated cardboard plants and/or for driving of production plants in the chemical industry. The slide bearings, the ball bearings and/or the production plants in the chemical industry are operated preferably at least temporarily at temperatures of above 160° C., more preferably above 180° C., especially above 200° C.
Preferred embodiments for the use of the invention encompass the embodiments described in relation to the high-temperature lubricant grease of the invention.
There follows a detailed elucidation of the invention with reference to experiments that do not restrict the invention. The greases described hereinafter are produced using the Hauschild Speedmixer DAC 700.1 FVZ. Mixing is always effected at 1000 rpm for 5 min.
Two inventive high-temperature lubricant greases are produced as follows:
Example Grease 1: In a vessel, 71.5 g of perfluoropolyetherol consisting of perfluoropropylene oxide as monomer, available as Aflunox 400 V, of viscosity 430 mm2/sec at 40 cst, was stirred together with 26.5 g of PPS micropowder having melting point 280° C. and median particle size D50=5 μm and 2 g of disodium sebacate as anticorrosion additive at 1000 rpm for 5 min in a Speedmixer, and the mixture was homogenized using a three-roll mill, giving a lubricant grease of NLGI class 2 (worked penetration 250 1/10 mm).
Example Grease 2: In a vessel, 71.7 g of perfluoropolyetherol was stirred together with 26.3 g of PEEK micropowder having melting point 340° C. and median particle size D50=10 μm and 2 g of disodium sebacate at 1000 rpm for 5 min in a Speedmixer, and the mixture was homogenized using a three-roll mill, giving a lubricant grease of NLGI class 2 (worked penetration 280 1/10 mm).
The tribological properties of the high-temperature lubricant greases produced in Example 1 are examined using a Tannert sliding friction testbed. This is a test instrument which is customary in tribological technology, described, for example, in T. Mang (editor), Encyclopedia of Lubricants and Lubrication, Springer, Berlin, Heidelberg 2014, and is used to examine friction characteristics in the case of slow oscillating movements. A sliding tab made of ST 37 steel with thickness 4.5 mm that has been greased with 0.5 g is moved back and forth at room temperature between two cylinder rolls (100Cr6 steel, diameter 10 mm, length 10 mm) in linear geometry in an oscillating manner at a speed of 0.243 mm/s. In the first cycle, the load was a normal force of 100 N. After each movement cycle of 200 mm, the normal force is increased by 50 N until occurrence of stick-slip or attainment of the maximum load of 1200 N. At the same time, the average friction force is ascertained continuously over each movement cycle. The studies are preferably conducted at 25° C.
The load stage obtained on occurrence of stick-slip and the average coefficient of friction present in the corresponding movement cycle are compared with the load stage and the coefficient of friction on occurrence of stick-slip of a PTFE-containing grease of the following composition:
Comparative Grease 3 (comparative example): In a vessel, 72.0 g of perfluoropolyetherol was stirred together with 28.0 g of PTFE micropowder having melting point 330° C. and median particle size D50=4 μm and 2.0 g of disodium sebacate at 1000 rpm for 5 min, and the mixture was homogenized using a three-roll mill, giving a lubricant grease of NLGI class 2 (worked penetration 280 1/10 mm).
It is found, as apparent from
As Table 1 shows, the example greases of the invention, with comparable low-temperature characteristics (flow pressure results), have much smaller oil depositions at 100° C. and 200° C., and so the perfluoropolyetherol is better retained in the grease. In the high-temperature lifetime test (FE 9), Example Grease 1 shows a distinct extension of the L 50 lifetime, and Example Grease 2 a distinctly improved extension of the L 10 lifetime.
The inventive high-temperature lubricant greases 4 and 5 are produced as follows:
Example Grease 4: In a tank, 8.1 g of lithium 12-hydroxystearate in 47.6 g of PAO 6 of viscosity 30 mm2/sec at 40° C. is brought to a temperature of 205° C. while stirring and cooled down gradually. After addition of 0.6 g of Irganox L 150, an aminic antioxidant, and 1.7 g of disodium sebacate, the mixture is homogenized using a three-roll mill, 42.0 g of PPS micropowder with melting point 280° C. and median particle size D50=5 μm is added, and the mixture is stirred at 1500 rpm for 10 min. The mixture is homogenized again using a three-roll mill, giving a lubricant grease of NLGI class 2 (worked penetration 295 1/10 mm).
Example Grease 5: In a tank, 7.9 g of lithium hydroxystearate in 46.2 g of PAO 6 of viscosity 30 cst at 40° C. is brought to a temperature of 205° C. while stirring and cooled down gradually. After addition of 0.6 g of Irganox L 150, an aminic antioxidant, and 1.7 g of disodium sebacate, the mixture is homogenized using a three-roll mill, 43.6 g of PEEK micropowder with melting point 340° C. and median particle size D50=10 μm is added, and the mixture is stirred at 1500 rpm for 10 min. The mixture is homogenized again using a three-roll mill, giving a lubricant grease of NLGI class 2 (worked penetration 290 1/10 mm).
The tribological properties of the high-temperature lubricant greases produced in Example 3 are determined using a Tannert sliding friction testbed. The resultant coefficients of friction are compared with the coefficients of friction of a PTFE-containing grease of the following composition:
Comparative Grease 6 (comparative example): In a tank, 9.1 g of lithium hydroxystearate in 53.3 g of PAO 6 of viscosity 30 cst at 40° C. is brought to a temperature of 205° C. while stirring and cooled down gradually. After addition of 0.7 g of Irganox L 150, an aminic antioxidant, and 1.9 g of disodium sebacate, the mixture is homogenized using a three-roll mill, 35.0 g of PTFE micropowder with melting point 330° C. and median particle size D50=4 μm is added, and the mixture is stirred at 1500 rpm for 10 min. The mixture is homogenized again using a three-roll mill, giving a lubricant grease of NLGI class 2 (worked penetration 280 1/10 mm).
It is found that the coefficients of friction of the inventive PPS-containing high-temperature lubricant grease are surprisingly lower than those of the PTFE-containing comparative grease. In addition, it is found that the coefficients of friction of the inventive PEEK-containing high temperature lubricant grease are only slightly higher than those of the PTFE-containing comparative grease. While the PTFE-containing comparative grease leads to stick-slip under a load of 300 N, the inventive PPS-containing high-temperature lubricant grease does not show any propensity at all with respect to stick-slip up to the maximum possible load of 1200 N.
In a vessel, 72.0 g of perfluoropolyetherol consisting of perfluoropropylene oxide as monomer, available as Aflunox 400 V, of viscosity 430 mm2/sec at 40 cst, was stirred together with 26.0 g of 1,3,5-triazine-2,4,6 (1H,3H,5H)-trithione, particle size D50=10 μm, and 2 g of disodium sebacate as anticorrosion additive at 1000 rpm for 5 min in a Speedmixer, and the mixture was homogenized using a three-roll mill, giving a lubricant grease of NLGI class 2 (worked penetration 259 1/10 mm).
In a vessel, 71.0 g of perfluoropolyetherol consisting of perfluoropropylene oxide as monomer, available as Aflunox 400 V, of viscosity 430 mm2/sec at 40 cst, was stirred together with 27.0 g of melamine phosphate, particle size D50=6.7 μm, and 2 g of disodium sebacate as anticorrosion additive at 1000 rpm for 5 min in a Speedmixer, and the mixture was homogenized using a three-roll mill, giving a lubricant grease of NLGI class 2 (worked penetration 271 1/10 mm).
The oil deposition of the greases of the invention, at 100° C., shows halving of the oil deposition compared to the comparative grease; at 200° C., there is only a slight increase. Low-temperature characteristics (flow pressure) are considered equivalent.
Friction characteristics (Tannert) are distinctly improved. Example Grease 7 shows improved lifetime in the FE 9 test. Example Grease 8 also meets the demands in the lifetime test (FE 9) very efficiently.
While subject matter of the present disclosure has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. Any statement made herein characterizing the invention is also to be considered illustrative or exemplary and not restrictive as the invention is defined by the claims. It will be understood that changes and modifications may be made, by those of ordinary skill in the art, within the scope of the following claims, which may include any combination of features from different embodiments described above.
The terms used in the claims should be construed to have the broadest reasonable interpretation consistent with the foregoing description. For example, the use of the article “a” or “the” in introducing an element should not be interpreted as being exclusive of a plurality of elements. Likewise, the recitation of “or” should be interpreted as being inclusive, such that the recitation of “A or B” is not exclusive of “A and B,” unless it is clear from the context or the foregoing description that only one of A and B is intended. Further, the recitation of “at least one of A, B and C” should be interpreted as one or more of a group of elements consisting of A, B and C, and should not be interpreted as requiring at least one of each of the listed elements A, B and C, regardless of whether A, B and C are related as categories or otherwise. Moreover, the recitation of “A, B and/or C” or “at least one of A, B or C” should be interpreted as including any singular entity from the listed elements, e.g., A, any subset from the listed elements, e.g., A and B, or the entire list of elements A, B and C.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2021 130 746.5 | Nov 2021 | DE | national |
| 21210197.6 | Nov 2021 | EP | regional |
This application is a U.S. National Phase application under 35 U.S.C. § 371 of International Application No. PCT/EP2022/082623, filed on Nov. 21, 2022, and claims benefit to German Patent Application No. DE 10 2021 130 746.5, filed on Nov. 24, 2021 and European Patent Application No. EP 21210197.6, filed on Nov. 24, 2021. The International Application was published in German on Jun. 1, 2023 as WO 2023/094321 A1 under PCT Article 21 (2).
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/082623 | 11/21/2022 | WO |
