Patent Application
20250019614
The invention relates to a lubricating grease comprising selected fluorine-free materials. The invention also relates to a process for producing the lubricating grease and its use for lubricating tribological systems, in particular tribological systems with high requirements in terms of energy efficiency even at low or high temperatures and/or tribological systems which are in contact with foodstuffs and/or drinking water.
For the lubrication of tribological systems with high requirements in terms of energy efficiency even at low or high temperatures, e.g. in the automotive industry, PTFE micropowders are often used as standard practice, as they can achieve very low friction levels.
As the PTFE micropowders also have a very high temperature stability, they are also often used as thickeners or additives in the lubrication of tribological systems at a high top service temperature, for example at operating temperatures of over 160° C. with no continuous relubrication option. The use of perfluorinated or polyfluorinated products, such as polyfluorinated polyethers or (fluorinated) silicon oils as base oils, is also common.
PTFE micropowders are also commonly used in applications involving contact with food or drinking water due to their low toxicity resulting from their chemical inertness. In principle, food contact lubricants are subject to legal regulations, such as certification according to NSF/H1 or NSF/H2. The classification “H1” has to be attained for lubricants that are in “incidental food contact”, i.e. in occasional, technically unavoidable contact with food. However, intentional or permanent contact must also be ruled out when using “H1” lubricants. Lubricants that are non-toxic and non-carcinogenic can attain an “H2” classification. When using “H2” lubricants, however, it is important to prevent any contact with food.
The PTFE powder can serve as both a thickening agent and an additive in consistent lubricants.
PTFE is known to have an excellent lubricating effect due to very low and constant coefficients of friction even under high loads, it can effectively prevent stick slip and shows good stability even when used under high shear stress. Additionally, it exhibits excellent chemical inertness to oxygen. This enables the prevention of oxidation-related deposits frequently occurring in lubricating greases due to the reaction of the thickener with atmospheric oxygen and the achievement of a uniform and long-lasting lubricating effect. The very favorable toxicological properties resulting from the good chemical and thermal stability of PTFE also ensure a high degree of safety in lubricant operation, even in applications with unavoidable food contact.
A disadvantage of the use of perfluorinated or polyfluorinated products is that they are problematic from an environmental point of view.
In an embodiment, the present disclosure provides a lubricating grease comprising:
In some embodiments, the lubricating grease is characterized in that the fluorine-free material is a fluorine-free polymer in accordance with option B1 and has a numerical ratio of aromatic carbon atoms and/or of carbon atoms contained in heteroaromatic structures of at least 20%, each based on the overall number of carbon atoms in the fluorine-free polymer.
In some embodiments, the lubricating grease is characterized in that the fluorine-free material is a fluorine-free polymer in accordance with option B1 and is selected from the group consisting of polyaryletherketone (PAEK), preferably polyetheretherketone (PEEK), even more preferably crosslinked PAEK, in particular crosslinked PEEK, polyphenylene sulfide (PPS), polyethersulphone (PES), poly(amide)imide (PAI), perylene imide, polycarbonate (PC), polyquinoline, polyquinoxaline, morpholine, in particular, phthalocyanine, melamine resin and blends thereof.
In some embodiments, the lubricating grease is characterized in that the fluorine-free material is crosslinked PAEK, in particular, crosslinked PEEK.
In some embodiments, the lubricating grease is characterized in that the fluorine-free material contains two or more of the fluorine-free materials of group B3 in combination, in particular talcum in combination with pyrogenic silicon dioxide, functionalized with organic groups; and/or contains at least one fluorine-free material selected from group B3 in combination with at least one fluorine-free material selected from group B6, in particular, pyrogenic silicon dioxide functionalized with organic groups, in combination with melamine cyanurate; and/or contains at least one fluorine-free material selected from group B3, in combination with at least one fluorine-free material selected from group B6, in combination with hexagonal boron nitride; and/or contains at least one fluorine-free material selected from group B3, in combination with hexagonal boron nitride.
In some embodiments, the lubricating grease is characterized in that the fluorine-free material contains pyrogenic silicon dioxide functionalized with organic groups, in combination with melamine cyanurate and in combination with hexagonal boron nitride.
In some embodiments, the lubricating grease is characterized in that the fluorine-free material contains pyrogenic silicon dioxide functionalized with organic groups, in combination with melamine cyanurate and in combination with hexagonal boron nitride.
In some embodiments, the lubricating grease is characterized in that the fluorine-free material and/or the lubricating grease is NSF/H1 approved.
In some embodiments, the lubricating grease is characterized in that the fluorine-free material functions as a thickener and the proportion of the fluorine-free material in relation to the overall weight of the lubricating grease is 10 to 55 wt. %.
In some embodiments, the lubricating grease is characterized in that the lubricating grease contains a further thickener, which is other than the fluorine-free material, preferably in a proportion of 3 wt. % to 30 wt. % based on the overall weight of the lubricating grease.
In some embodiments, the lubricating grease is characterized in that the fluorine-free material functions as an additive to reduce the coefficient of friction, wherein the proportion of the fluorine-free material, based on the overall weight of the lubricating grease, is from 1 wt. % to 10 wt. %.
In some embodiments, the lubricating grease is characterized in that the lubricating grease contains a thickening agent, which is other than the fluorine-free material, preferably in a proportion of 3 wt. % to 40 wt. % based on the overall weight of the lubricating grease.
In some embodiments, the lubricating grease is characterized in that the base oil is selected from group consisting of esters, preferably dipentaerythrite esters, trimellitic acid esters, hemimellitic acid esters, pyromellitic acid esters, estolides, pentaerythrite esters, dimer acid esters, trimer acid esters, trimethylol propane esters (TMP esters); ethers, preferably polyphenylene ethers, diaryl ethers, triaryl ethers, polyglycols, linear or branched perfluoro polyether oils (PFPE oils); synthetic hydrocarbons, preferably alkylzied naphthalines, polyalphaolefins (PAOs), metallocene polyalphaolefins (mPAOs); untreated and chemically modified vegetable oils, group III oils; gas-to-liquid (GTL) oils; dimethyl silicone oils; arylized silicone oils, preferably alcylaryl silicone oils, in particular, methyl-aryl silicone oils and completely arylized silicone oils, which can be used alone or in combination.
In some embodiments, the lubricating grease is characterized in that the fluorine-free material is inorganic layered silicate, preferably talcum, bentonite, mica, pyrogenic silicon dioxide, pyrogenic silicon dioxide functionalized with organic groups, and/or mixtures thereof, in combination with a layered solid lubricant that is not an inorganic layered silicate.
In another embodiment, the present disclosure provides a method of manufacturing a lubricating grease according to the invention, comprising mixing of the following components:
In another embodiment, the present disclosure provides a use of a lubricating grease for the lubrication of tribological systems, in particular, of tribological systems in applications in which a high top usage temperature of preferably more than 160° C., more preferably more than 180° C., in particular more than 200° C., is necessary, and/or for the lubrication of tribological systems in which an application spectrum is necessary in the temperature range from −40° C. to 160° C.
In some embodiments, the present disclosure provides a use of a lubricating grease for the lubrication of tribological systems, which are in contact with foodstuffs and/or drinking water, in particular, of working apparatus in food processing and/or for gas and (drinking) water fittings.
In some embodiments, the use is characterized in that the fluorine-free material is silicone resin, lignin and mixtures thereof (option B2) and the lubricating grease is used for the lubrication of working apparatus in food processing and/or for gas and (drinking) water fittings.
In some embodiments, the present disclosure provides a use of a lubricating grease for the lubrication of tribological systems, in particular, for the lubrication of tribological systems, which are in contact with foodstuffs and/or drinking water, for example working apparatus in food processing, such as chains for transport in freezing tunnels and conveyer belts, transmissions, antifriction and plain bearings, pneumatic cylinders, seals, installation pastes, valves and fittings, for gas and (drinking) water fittings; and/or for the lubrication of components in the automotive industry, such as ball-type linear drives in automotive steering applications, actuators; transmissions, plastic transmissions, seals, seals in sliding sunroofs, brake boosters and/or antifriction bearings, plain bearings and/or linear guides.
It is the object of the present invention to provide a lubricating grease in which the use of PTFE as a thickener or additive can be dispensed with and which nevertheless has low coefficients of friction. Furthermore, the lubricating grease is to be used for the lubrication of tribological systems with high requirements in terms of energy efficiency over a wide temperature range, e.g. in the automotive industry, and in addition is to be manufactured in compliance with NSF/H1.
The object is solved by a lubricating grease comprising
The content of polytetrafluoroethylene in the lubricating grease is preferably determined on the basis of the enthalpy of fusion of PTFE using the standard DIN EN ISO 11357-1, publication date 2008.04. The measurement is conveniently carried out as follows: The oil phase of the lubricating grease, including the soluble portions of additives, is separated from solid, insoluble components (e.g. thickeners, insoluble additives and/or solid lubricants) by extraction with a suitable solvent, as this increases the accuracy of the measurement. The polytetrafluoroethylene is part of the insoluble components. Depending on the base oil used, special petrol 80/110, ethanol and/or methyl perfluorobutyl ether are particularly suitable as solvents. Special petrol 80/110 is particularly suitable for lubricating greases whose base oils contain mineral oils, PAO, alkylated aromatics, phenyl ethers, esters, silicone oils and polyglycols with no or a low content of ethylene oxide and mixtures thereof. Ethanol is particularly suitable for lubricating greases that contain base oils made from polyglycols with a high ethylene oxide content. Methyl perfluorobutyl ether is particularly suitable for lubricating greases that contain perfluoropolyethers as base oils. Lubricating greases containing two immiscible oils should preferably be extracted twice. Such lubricating greases are usually referred to as hybrid lubricating greases. For example, such hybrid lubricating greases can contain both perfluoropolyethers and preferably esters. Such a hybrid lubricating grease is therefore preferably extracted with both special petrol 80/110 and methyl perfluorobutyl ether in order to separate both oils and the additives dissolved therein. The solvent residues are removed from the residue obtained. The resulting dried residue is then measured in relation to the amount of lubricating grease used. This gives the proportion of residue in weight %. 20 mg of the dry residue is weighed into an aluminum DSC crucible with 25 μI volume 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 (enthalpy sample) is proportional to the amount of PTFE in the residue. For calibration, a pure PTFE micropowder (particle size D50 according to ASTM D4894=5 μm, melt flow index at 372° C./2.16 kg/2,095 mm according to ASTM D1238)=0.5 g/10 min) is measured in an analogous fashion (enthalpy reference). The content of PTFE in the lubricating grease is calculated according to the following equation:
(enthalpy sample)/(enthalpy reference)*proportion of residue in wt. %=PTFE content in wt. %
The term “fluorine-free material” according to the invention is understood in the general sense. Thus, a fluorine-free material is understood to mean materials that do not contain any fluorine atoms in their chemical composition.
The term “fluorine-free polymer” according to the invention is understood in the general sense. Thus, a fluorine-free polymer is understood to mean polymers which are composed of monomers which do not contain any fluorine atoms in their chemical composition.
The term “lubricating grease” according to the invention is understood in the general sense. Thus, lubricating greases are understood to be solid to semi-fluid substances which can be produced by dispersing a thickening agent into a liquid lubricant. In addition to the thickening agent, lubricating greases can also contain other additives that give the lubricating grease special properties. Lubricating greases are explained in the standard ASTM D217-21, publication date 2021.07.
Surprisingly, it was found that the lubricating grease according to the invention can largely or even completely dispense with the use of PTFE as a thickening agent or as an additive while still maintaining very low coefficients of friction, making it suitable for lubricating tribological systems with high energy efficiency requirements, such as those found in the automotive industry and can be used over a wide temperature range. In addition, the lubricating grease can be manufactured to be NS/H1-compliant.
Particularly in practical tests, it was found that the fluorine-free materials used according to the invention can achieve a performance equivalent to PTFE and even in some cases superior to PTFE. In practical tests, for example, a thickening effect comparable to PTFE and in some cases with even significantly lower coefficients of friction and shear viscosities compared to PTFE were achieved, which enables even greater energy efficiency.
According to the invention, the lubricating grease preferably has at least one fluorine-free material.
In one embodiment of the invention, the fluorine-free material is a fluorine-free polymer which has aromatic, heteroaromatic and/or heterocyclic groups and a melting or decomposition point, measured according to DIN EN ISO 11357-1, publication date 2008.04, of higher than 200° C. (option B1). The fluorine-free polymer may be present as a single substance or as a mixture of different substances, as is generally understood.
In addition to their good lubricating effect, the advantage of using these materials is that they allow the lubricating grease to be used over a wide range of applications from low temperatures (−40° C.) to high-temperature lubrication (>160° C.).
In addition, it was found that the fluorine-free polymer can achieve a performance equivalent to PTFE and even superior in some cases. In practical tests, a thickening effect comparable to PTFE and even in some cases significantly lower coefficients of friction compared to PTFE were achieved, which enables even greater energy efficiency.
It was also found that oil separation values equivalent to or even significantly lower than PTFE can be achieved, even at temperatures above 160° C. This important parameter for consistent lubricants shows that the specific fluorine-free polymer used according to the invention can achieve a prolonged lubricating effect compared to PTFE, even at high temperatures.
It is further advantageous that the lubricating grease according to the invention can be manufactured to be NS/H1-compatible.
Particularly preferably, the fluorine-free polymer according to option B1 has a numerical proportion of aromatic carbon atoms and/or of carbon atoms contained in heteroaromatic structures of at least 20%, for example from 20% to 100%, even more preferably of at least 50%, for example from 50% to 100%, and in particular of at least 70%, for example from 70% to 100%, in each case based on the overall number of carbon atoms in the fluorine-free polymer. The high proportion of aromatic carbon atoms and/or of carbon atoms contained in heteroaromatic structures has a positive effect on the high-temperature stability of the lubricating grease.
Also particularly preferably, the fluorine-free polymer has a numerical ratio of aromatic carbon atoms and/or carbon atoms contained in heteroaromatic structures to aliphatic carbon atoms of at least 1:5, even more preferably of at least 1:1 and in particular of at least 5:1.
Preferred heteroaromatic groups and/or heterocyclic groups contain, independently of one another, nitrogen, oxygen and/or sulfur.
According to the invention, the fluorine-free polymer is particularly preferably selected from the group consisting of polyaryletherketone (PAEK), preferably polyetheretherketone (PEEK), even more preferably crosslinked PAEK, in particular crosslinked PEEK, polyphenylene sulfide (PPS), polyethersulphone (PES), poly(amide)imide (PAI), perylene imide, polycarbonate (PC), polyquinoline, polyquinoxaline, morpholine, phthalocyanine, melamine resin and blends thereof. Copolymers of the aforementioned groups are also conceivable.
According to the invention, the fluorine-free polymer is also particularly preferably selected from the group consisting of polyaryletherketone (PAEK), preferably polyetheretherketone (PEEK), even more preferably crosslinked PAEK, in particular crosslinked PEEK, polyphenylene sulfide (PPS), polyethersulphone (PES), poly(amide)imide (PAI), perylene imide, whereby perylene imide is to be understood as polymeric perylene diimide, polycarbonate (PC), polyquinoline, polyquinoxaline, polymorpholine, melamine resin and blends thereof. Copolymers of the aforementioned groups are also conceivable.
Particularly preferably, the fluorine-free polymer is selected from the group consisting of polyaryletherketone (PAEK), preferably polyetheretherketone (PEEK), even more preferably crosslinked PAEK, in particular crosslinked PEEK, polyphenylene sulfide (PPS), melamine resin, polyethersulphone (PES), perylene imide and blends thereof. Copolymers of the aforementioned groups are also conceivable.
The PAEK can, for example, be a polyether ether ketone (PEEK), a polyether ketone (PEK), a poly(ether ketone ketone) (PEKK), a poly(ether ether ether ketone) (PEEEK), a poly(ether ketone ether ketone ketone) (PEKEKK) and/or a poly(ether ether ketone ketone) (PEEKK). PEEK is preferred according to the invention.
Particularly preferably, the fluorine-free polymer is selected from the group consisting of polyaryletherketone (PAEK), preferably polyetheretherketone (PEEK), even more preferably crosslinked PAEK, in particular crosslinked PEEK, polyphenylene sulfide (PPS), melamine resin and blends thereof. Copolymers of the aforementioned groups are also conceivable.
Most particularly preferably, the fluorine-free polymer is selected from the group consisting of polyaryletherketone (PAEK), preferably polyetheretherketone (PEEK), even more preferably crosslinked PAEK, in particular crosslinked PEEK, polyphenylene sulfide (PPS) and blends thereof. Copolymers of the aforementioned groups are also conceivable.
In a particularly preferred embodiment, the fluorine-free polymer is crosslinked PAEK, in particular crosslinked PEEK. It has been found that crosslinked PAEK, and in particular crosslinked PEEK, has especially advantageous properties in terms of flexibility and temperature stability due to its increased glass transition range.
The crosslinked PAEK, preferably the crosslinked PEEK, is preferably obtained by crosslinking PAEK, preferably PEEK with at least one crosslinking agent, which is capable of thermal crosslinking with the keto groups of PAEK and/or PEEK whilst forming at least two imine groups per crosslinking agent molecule. The crosslinker is preferably selected from
The crosslinker under a) is preferred.
Further preferably, the crosslinker is selected from polyamides, polyimides, aminated dimer fatty acids, oligo-/polymers containing aminated dimer fatty acids in polymerised form and mixtures thereof.
Further preferably, the crosslinker is an oligo-/polymer having at least two amide groups, the oligo-/polymer comprising monomers in polymerised form 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 each preferably selected from unsubstituted or substituted phthalic acids, terephthalic acids, isophthalic acids, naphthalene dicarboxylic acids or diphenyl dicarboxylic 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 and 1,4-bisaminomethylcyclohexane, 5-amino-2,2, 4-trimethyl-1-cyclopentanemethylamine, 5-amino-1,3,3-trimethylcyclohexane methylamine (isophorone diamine), 3,3′-dimethyl-4,4′-diaminodicyclohexylmethane, [3-(aminomethyl)-2-bicyclo[2. 2.1]heptanyl]methaneamine, aminated dimer 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 6.1, PA 8.1, PA 9.1, PA 10.1, PA 12.1, PA 6.T/6, PA 6.T/10, PA 6.T/12, PA 6.T/6.I, PA6.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, PA6.T/6.1/12, PA6. T/6.1/6.10, PA6.T/6.1/6.12, PA 6. T/6.6, PA 6.T/6.10, PA 6.T/6.12, PA 10.T/6, PA 10.T/1 1, 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.I/46, PA 4.T/4.I/6.6, PA 5.T/5.I, PA 5.T/5.115.6, PA 5.T/5.116.6, PA 6.T/6.116.6, 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, PA 6.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 preferred is the crosslinker a saturated, alicyclic compound which has at least two primary amino groups, selected from aminized dimer fatty acids, oligo-/polymers which contain aminized dimer fatty acids in polymerized form and mixtures thereof, in particular, the compound
or oligo-/polymers containing this compound in polymerized form.
The amount of crosslinker can be adjusted with regard to the desired degree of crosslinking. Preferably, the proportion of crosslinker is 0.5 wt. % to 20 wt. %, preferably 1 wt. % to 10 wt. %, in particular 4 wt. % to 10 wt. %, in each case based on the overall weight of crosslinker and PAEK and in particular in each case based on the overall weight of crosslinker and PEEK. It was found that the stability of the product with such a crosslinker content can be particularly advantageous. In particular, by adjusting the amount of crosslinker in this range, particularly good flexibility and temperature stability can be achieved.
In a further preferred embodiment, the crosslinker is a di(aminophenyl) compound in which the two aminophenyl rings are linked to one another via an aliphatic group which has a carbocyclic residue. Most preferably, the crosslinker is a compound of the formula
The aromatic, heteroaromatic and/or heterocyclic groups can also be modified with heteroatoms, in particular with sulfur and/or phosphorus. Herein, the heteroatoms can be incorporated in the heteroaromatic and/or heterocyclic structure of the heteroaromatic and/or heterocyclic groups. However, the heteroatoms can also bridge the heteroaromatic and/or heterocyclic groups or be present as a substituent. Additionally, the heteroatoms may bridge the aromatic groups and/or be present as a substituent.
According to the invention, the fluorine-free polymer has a melting or decomposition point, measured according to DIN EN ISO 11357-1, publication date 2008.04, of higher than 200° C., more preferably 220° C. to 240° C., in particular 240° C. to 400° C.
Lubricating greases according to the invention, which contain a fluorine-free polymer according to option (B1), are well suited for the lubrication of tribological systems in applications in which a high top service temperature of preferably above 160° C., more preferably above 180° C., in particular above 200° C., is necessary, for example for the lubrication of plain bearings, in particular chains, antifriction bearings and/or for driving production plants in the chemical industry, which are operated at least intermittently at temperatures of above 160° C., more preferably above 180° C., in particular above 200° C.
In a preferred embodiment, the fluorine-free material is a fluorine-free phthalocyanine (B1). The phthalocyanine may be present as a single substance or as a mixture of different substances, as is common understanding.
In a further preferred embodiment (option B2), the fluorine-free material is silicone resin, lignin and/or mixtures thereof. The silicone resin and the lignin may be present as a single substance or as a mixture of different substances, as is common understanding.
Lubricating greases according to the invention, which contain silicone resin or lignin as a fluorine-free material, are particularly suitable for replacing PTFE-containing H1-approved metal soap lubricating greases and silicone-based products in drinking water fittings. The advantage here is the low hardness of these materials, which has a wear-protecting and damping effect when used in combination with the ceramic mating surfaces often found in drinking water fittings.
In a further preferred embodiment of the invention, the fluorine-free material is inorganic layered silicate, preferably talcum, bentonite, mica, pyrogenic silicon dioxide, pyrogenic silicon dioxide functionalized with organic groups, and/or mixtures thereof (option B3). The inorganic layered silicate and the pyrogenic silicon dioxide may be present as a single substance or as a mixture of different substances, as is common understanding. The advantage of these materials is that they can be used to achieve a friction level similar to that of PTFE, even under high tribological loads. Lubrication concepts can also be realized with significantly lower shear viscosities compared to PTFE products. This is an indication of excellent energy efficiency.
In a further preferred embodiment, the fluorine-free material is inorganic layered silicate, preferably talcum, bentonite, mica, pyrogenic silicon dioxide, pyrogenic silicon dioxide functionalized with organic groups, and/or mixtures thereof, in combination with a layered solid lubricant which is not an inorganic layered silicate, in particular with hexagonal boron nitride, graphite, graphene, M0S2 and/or mixtures thereof.
Suitable pyrogenic silicon dioxide is described, for example, in the technical journal “Technical Overview: Aerosil-Fumed Silicon dioxide from Evonic Industries” 03-2017. This journal also describes suitable pyrogenic silicon dioxide functionalized with organic groups.
In a particularly preferred embodiment, the fluorine-free material contains pyrogenic silicon dioxide functionalized with organic groups. Particularly preferably, the functionalized pyrogenic silicon dioxide has a BET surface area, measured according to ISO 9277 2014 01, of 10 to 500 m2/g, even more preferably of 50 to 400 m2/g, in particular of 50 to 200 m2/g. Further preferably, the functionalized pyrogenic silicon dioxide has a primary particle size, measured by transmission electron microscopy, of 5 to 50 nm. Further preferably, the functionalized pyrogenic silicon dioxide has a tamped density, measured according to ISO787/11 1995, of 50 g/I to 280 g/I, more preferably of 50 g/I to 200 g/I. Further preferably, the functionalized pyrogenic silicon dioxide has a carbon content, measured according to ISO-3262-20 2021, of 0.5 wt. % to 8.8 wt. %, preferably of 0.5 wt. % to 6 wt. %, in particular 0.5 wt. % to 2 wt. %.
Preferred organic groups are branched or unbranched aliphatic and/or aromatic groups with preferably 1 to 20 carbon atoms. Preferred aromatic groups have 6 to 10 carbon atoms. Preferred aliphatic groups have 1 to 10 carbon atoms. Particularly preferred organic groups are methyl, ethyl, propyl, vinyl, butyl, pentyl, hexyl, heptyl, octyl and/or phenyl. Very particularly preferred organic groups are methyl groups. The advantage of using these materials is that they provide a friction level comparable to PTFE, even under high tribological loads, and enable lubrication concepts with significantly lower shear viscosities as compared to PTFE products.
In a further preferred embodiment, the fluorine-free material is nanoparticulate silicon dioxide functionalized with organic groups (option B4). The nanoparticulate silicon dioxide can be a single substance or can be a mixture of various substances, as is generally understood. Preferred organic groups are branched or unbranched aliphatic and/or aromatic groups with preferably 1 to 20 carbon atoms. Preferred aromatic groups have 6 to 10 carbon atoms. Preferred aliphatic groups have 1 to 10 carbon atoms. Particularly preferred organic groups are methyl, ethyl, propyl, vinyl, butyl, pentyl, hexyl, heptyl, octyl and/or phenyl. The advantage of using these materials is that they provide a friction level comparable to PTFE, even under high tribological loads, and enable lubrication concepts with significantly lower shear viscosities as compared to PTFE products.
In a further preferred embodiment, the fluorine-free material is a phosphorus compound, in particular zinc pyrophosphate, calcium (pyro)phosphate and zirconium hydrogen phosphate and/or mixtures thereof (option B5). The phosphorus compound may be present as a single substance or as a mixture of different substances, as is common understanding. Lubricating greases containing these fluorine-free materials have very favorable friction coefficient levels and, at least in part (especially zirconium hydrogen phosphate), further improved wear protection properties compared to PTFE.
In a further preferred embodiment (option B6), the fluorine-free material is a melamine derivative, preferably melamine cyanurate, melamine phosphate, in particular melamine monophosphate and/or 1,3,5-triazine-2,4,6 (1H,3H,5H)-trithione. In one embodiment, the fluorine-free material is melamine phosphate, in particular melamine monophosphate and/or 1,3,5-triazine-2,4,6 (1H,3H,5H)-trithione. Melamine cyanurate is preferred. The melamine derivative and the 1,3,5-triazine-2,4,6 (1H,3H,5H)-trithione may be present as one substance or as a mixture of different substances, as is common understanding.
Lubricating greases containing these fluorine-free materials exhibit very favorable friction coefficient levels and, at least in part (especially melamine phosphate), further improved wear protection properties compared to PTFE. In particular, the use of melamine phosphate in a lubricant reduces shear viscosity compared to PTFE and thus leads to increased energy efficiency.
The lubricating grease according to the invention may contain fluorine-free materials selected from one or more of the groups B1, B2, B3, B4, B5 and/or B6. Thus, the lubricating grease according to the invention may only contain one of components B1, B2, B3, B4, B5 or B6. However, the lubricating grease according to the invention may also contain mixtures comprising two or more of the fluorine-free materials according to options B1, B2, B3, B4, B5 and/or B6.
In a preferred embodiment of the invention, the lubricating grease contains two or more of the fluorine-free materials of group B3 in combination, in particular talcum in combination with pyrogenic silicon dioxide functionalized with organic groups. A silicone oil is preferably used as a base oil. The silicone oil is preferably an alkylated, even more preferably a methylated silicone oil, in particular dimethyl silicone oil. Dimethyl silicone oil is also known as polydimethylsiloxane (PDMS). The silicone oil preferably has a kinematic viscosity at 25° C. determined according to DIN 53019, publication date 2008.09, of 20 mm2/sec to 2000000 mm2/sec, even more preferably from 50 mm2/sec to 10000 mm2/sec, even more preferably from 100 to 5000 mm2/sec, even more preferably from 500 to 3000 mm2/sec.
Thus, a particularly preferred embodiment according to the invention (embodiment I) comprises a lubricating grease comprising
Preferred embodiments of embodiment I in addition to those described according to the invention comprise in particular the following: A particularly preferred functionalized pyrogenic silicon dioxide is alkylated, in particular methylated pyrogenic silicon dioxide, most preferably pyrogenic silicon dioxide modified with dimethyldichlorosilane. The functionalized pyrogenic silicon dioxide preferably has a BET surface area, measured according to ISO 9277 2014 01, of 50 to 400 m2/g. The proportion of pyrogenic silicon dioxide functionalized with organic groups is, based on the overall weight of the lubricating grease, preferably 0.5 to 20 wt. %, more preferably 1 to 10 wt. %, in particular 2 to 10 wt. %. The talcum preferably has an average particle size D50 of 1 to 30 μm, preferably 2 to 15 μm, measured according to ISO 13320-1 (1999). The proportion of talcum, based on the overall weight of the lubricating grease, is preferably from 1 to 54 wt. %, more preferably from 4 to 54 wt. %, in particular from 10 to 54 wt. %. The proportion of fluorine-free material in total, based on the overall weight of the lubricating grease, is preferably 1 wt. % to 10 wt. %, more preferably 5 wt. % to 7 wt. %, in particular 1 wt. % to 5 wt. % or 10 to 55 wt. %, even more preferably 20 to 50 wt. %, in particular 30 to 50 wt. %. The proportion of base oil, based on the overall weight of the lubricating grease, is preferably 30 wt. % to 88 wt. %, more preferably 50 wt. % to 88 wt. %. A silicone oil is preferably used as the base oil. The silicone oil is preferably an alkylated, even more preferably a methylated silicon oil, in particular dimethyl silicone oil. The silicone oil preferably has a kinematic viscosity at 25° C. determined according to DIN 53019, publication date 2008.09, of 20 mm2/sec to 2000000 mm2/sec, even more preferably from 50 mm2/sec to 10000 mm2/sec, even more preferably from 100 to 5000 mm2/sec, even more preferably from 500 to 3000 mm2/sec.
In a preferred embodiment, the lubricating grease according to the invention comprises fluorine-free materials selected from two or more than two of groups B1, B2, B3, B4, B5 and/or B6 (option B7).
Thus, in a preferred embodiment, the fluorine-free material comprises at least one fluorine-free material selected from group B3 in combination with at least one fluorine-free material selected from group B6. Preferably, a silicone oil is used as the base oil. The silicone oil is preferably an alkylated, even more preferably a methylated silicone oil, in particular dimethyl silicone oil. The silicone oil preferably has a kinematic viscosity at 25° C., determined according to DIN 53019, publication date 2008.09, of 20 mm2/sec to 2000000 mm2/sec, even more preferably from 50 mm2/sec to 10000 mm2/sec, even more preferably from 100 to 5000 mm2/sec, even more preferably from 500 to 3000 mm2/sec.
Furthermore, the fluorine-free material preferably contains a) melamine derivative, in particular melamine cyanurate, melamine phosphate and/or 1,3,5-triazine-2,4,6 (1H,3H,5H)-trithione, in combination with b) inorganic layered silicate, preferably talcum, bentonite, mica, pyrogenic silicon dioxide, pyrogenic silicon dioxide functionalized with organic groups, and/or mixtures thereof. The combination of melamine cyanurate with pyrogenic silicon dioxide functionalized with organic groups is particularly preferred.
In a further preferred embodiment of the invention, the fluorine-free material comprises a) melamine derivative, in particular melamine cyanurate, melamine phosphate and/or 1,3,5-triazine-2,4,6 (1H,3H,5H)-trithione, in combination with b) inorganic layered silicate preferably talcum, bentonite, mica, pyrogenic silicon dioxide, pyrogenic silicon dioxide functionalized with organic groups and/or mixtures thereof and in combination with c) hexagonal boron nitride.
A particularly preferred embodiment of the invention (embodiment II) comprises a lubricating grease comprising
A further particularly preferred embodiment of the invention (embodiment III) comprises a lubricating grease comprising
Preferred embodiments of embodiments II and III comprise, in addition to those described according to the invention, in particular the following: Out of the fluorine-free materials melamine cyanurate, melamine phosphate and/or 1,3,5-triazine-2,4,6 (1H,3H,5H)-trithione (B6), melamine cyanurate is particularly preferred. The melamine cyanurate, melamine phosphate and/or 1,3,5-triazine-2,4,6 (1H,3H,5H)-trithione (B6) preferably has an average particle size D50 of 1 μm to 15 μm, in particular of 1 μm to 5 μm, according to ISO 13320-1 (1999). Out of the inorganic layered silicates, pyrogenic silicon dioxide functionalized with organic groups is particularly preferred. A particularly preferred functionalized pyrogenic silicon dioxide is alkylated, in particular methylated pyrogenic silicon dioxide, most preferably pyrogenic silicon dioxide modified with dimethyldichlorosilane. The functionalized pyrogenic silicon dioxide preferably has a BET surface area, measured according to ISO 9277 2014 01, of 50 to 400 m2/g. The proportion of inorganic layered silicate, in particular of pyrogenic silicon dioxide functionalized with organic groups, is preferably from 0.5 to 20 wt. %, more preferably from 1 to 10 wt. %, in particular from 2 to 10 wt. %, based on the overall weight of the lubricating grease. The proportion of melamine cyanurate, melamine phosphate and/or 1,3,5-triazine-2,4,6 (1H,3H,5H)-trithione, based on the overall weight of the lubricating grease, is preferably from 1 to 54 wt. %, more preferably from 4 to 30 wt. %, in particular from 10 to 30 wt. %. The proportion of fluorine-free material in total, based on the overall weight of the lubricating grease, is preferably 1.5 wt. % to 55 wt. %, more preferably from 4 wt. % to 40 wt. %, in particular from 10 to 30 wt. %. The proportion of base oil, based on the overall weight of the lubricating grease, is preferably 30 wt. % to 88 wt. %, more preferably 50 wt. % to 88 wt. %. A silicone oil is preferably used as the base oil. The silicone oil is preferably an alkylated, even more preferably a methylated silicone oil, in particular dimethyl silicone oil. The silicone oil preferably has a kinematic viscosity at 25° C., determined according to DIN 53019, publication date 2008.09, of 20 mm2/sec to 2000000 mm2/sec, even more preferably from 50 mm2/sec to 10000 mm2/sec, even more preferably from 100 to 5000 mm2/sec, even more preferably from 500 to 3000 mm2/sec.
In a further preferred embodiment of embodiment III, the hexagonal boron nitride has an average particle size D50 of from 0.2 μm to 30 μm, preferably from 0.5 μm to 20 μm, measured according to ISO 13320-1 (1999). The proportion of hexagonal boron nitride, based on the overall weight of the lubricating grease, is preferably from 10 to 30 wt. %, preferably from 15 to 30 wt. %.
In a further preferred embodiment of the invention, the fluorine-free material comprises at least one fluorine-free material selected from group B3 in combination with hexagonal boron nitride. Preferably, a silicone oil is used as the base oil. The silicone oil is preferably an alkylated, even more preferably a methylated silicone oil, in particular dimethyl silicone oil. The silicone oil preferably has a kinematic viscosity at 25° C., determined according to DIN 53019, publication date 2008.09, of 20 mm2/sec to 2000000 mm2/sec, even more preferably from 50 mm2/sec to 10000 mm2/sec, even more preferably from 100 to 5000 mm2/sec, even more preferably from 500 to 3000 mm2/sec.
A further particularly preferred embodiment of the invention (embodiment IV) comprises a lubricating grease comprising
Preferred embodiments of embodiment IV comprise, in addition to those described according to the invention, in particular the following: From among the inorganic layered silicates, pyrogenic silicon dioxide functionalized with organic groups is particularly preferred. A particularly preferred functionalized pyrogenic silicon dioxide is alkylated, in particular methylated, pyrogenic silicon dioxide, most preferably pyrogenic silicon dioxide modified with dimethyldichlorosilane. The functionalized pyrogenic silicon dioxide preferably has a BET surface area, measured according to ISO 9277 2014 01, of 50 to 400 m2/g. The proportion of inorganic layered silicate, in particular of pyrogenic silicon dioxide functionalized with organic groups, based on the overall weight of the lubricating grease, is preferably 0.5 to 20 wt. %, more preferably from 1 to 10 wt. %, in particular from 2 to 10 wt. %. The proportion of fluorine-free material in total, based on the overall weight of the lubricating grease, is preferably 1 wt. % to 10 wt. %, even more preferably from 5 wt. % to 7 wt. %, in particular from 1 wt. % to 5 wt. % or 10 to 55 wt. %, even more preferably from 20 to 50 wt. %, in particular from 30 to 50 wt. %. The proportion of base oil, based on the overall weight of the lubricating grease, is preferably 30 wt. % to 88 wt. %, more preferably 50 wt. % to 88 wt. %. A silicone oil is preferably used as the base oil. The silicone oil is preferably an alkylated, even more preferably a methylated, silicone oil, in particular dimethyl silicone oil. The silicone oil preferably has a kinematic viscosity at 25° C., determined according to DIN 53019, publication date 2008.09, of 20 mm2/sec to 2000000 mm2/sec, even more preferably from 50 mm2/sec to 10000 mm2/sec, even more preferably from 100 to 5000 mm2/sec, even more preferably from 500 to 3000 mm2/sec.
The hexagonal boron nitride preferably has an average particle size D50 of 0.2 μm to 30 μm, preferably from 0.5 μm to 20 μm, measured according to ISO 13320-1 (1999). The proportion of hexagonal boron nitride, based on the overall weight of the lubricating grease, is preferably from 10 to 30 wt. %, preferably from 15 to 30 wt. %.
In a further preferred embodiment of the invention, the fluorine-free material comprises
A further particularly preferred embodiment of the invention (embodiment V) comprises a lubricating grease comprising
A further particularly preferred embodiment of the invention (embodiment VI) comprises a lubricating grease comprising
Preferred embodiments of embodiments V and VI comprise those described according to the invention and, in particular, those described with respect to embodiments I to IV.
In a further preferred embodiment of the invention, the fluorine-free material is an at least proportionally inorganic material, preferably inorganic layered silicate, in particular talcum, bentonite, mica, pyrogenic silicon dioxide, pyrogenic silicon dioxide functionalized with organic groups, and/or mixtures thereof (B3); nanoparticulate silicon dioxide functionalized with organic groups (B4); a phosphorus compound, in particular zinc pyrophosphate, calcium (pyro)phosphate, zirconium hydrogen phosphate and/or mixtures thereof (B5); and/or mixtures thereof.
In a further preferred embodiment of the invention, the fluorine-free material is an organic material, preferably a fluorine-free polymer, which has aromatic, heteroaromatic and/or heterocyclic groups and a melting or decomposition point, measured according to DIN EN ISO 11357-1, publication date 2008.04, of higher than 200° C., fluorine-free phthalocyanine and mixtures thereof (B1); silicone resin, lignin and mixtures thereof (B2); a melamine derivative, in particular melamine cyanurate, melamine phosphate and/or 1,3,5-triazine-2,4,6 (1H,3H,5H)-trithione (B6); and/or mixtures thereof.
According to the invention, the fluorine-free material has an average particle size D50 of less than 80 μm, for example 1 μm to 80 μm, even more preferably from 1 μm to 50 μm, even more preferably from 1 μm to 20 μm, in particular from 1 μm to 15 μm, in each case measured according to ISO 13320-1, publication date 2020-01. Preferably, the samples are measured dry at a test pressure of 4 bar. A suitable measuring device is, for example, a Malvern Mastersizer 3000.
The advantage of using the fluorine-free material having an average particle size of less than 80 μm is that the material can be very easily and homogeneously distributed in the lubricating grease and, due to the increased specific surface area (BET surface area), it has an improved thickening effect and can easily reach the friction point.
According to the invention, the lubricating grease does not contain polytetrafluoroethylene, and/or contains polytetrafluoroethylene in a proportion of less than 4 wt. %, even more preferably less than 2 wt. %, even more preferably less than 1 wt. %, even more preferably less than 0.1 wt. %, in each case based on the overall weight of the lubricating grease. This is advantageous for environmental reasons.
According to the invention, the lubricating grease does not contain polytetrafluoroethylene, and/or contains polytetrafluoroethylene in a proportion of less than 4 wt. %, more preferably less than 2 wt. %, even more preferably less than 1 wt. %, even more preferably less than 0.1 wt. %, in each case in relation to the overall weight of the lubricating grease. This is advantageous for environmental reasons.
In a preferred embodiment, the lubricating grease further does not contain any per- or polyfluorinated products, and/or contains per- or polyfluorinated products only in a proportion of less than 4 wt. %, even more preferably less than 2 wt. %, even more preferably less than 1 wt. %, even more preferably less than 0.5 wt. % and, in particular, less than 0.1 wt. %, in each case based on the overall weight of the lubricating grease.
In a further preferred embodiment of the invention, the fluorine-free material is NSF/H1-approved. The fluorine-free material is thus preferably selected such that approval as a lubricant with food contact is possible. Particularly preferably, all raw materials of the lubricating grease are selected in such a way that approval according to NSF-H1 is possible. Consequently, the lubricating grease according to the invention can be used in applications involving contact with foodstuffs. This makes it ideal, for example, for lubricating tribological systems which are in contact with foodstuffs and/or drinking water, in particular tools used in food processing and/or for gas and (drinking) water fittings.
According to the invention, the proportion of fluorine-free material, based on the overall weight of the lubricating grease, is 1 to 55 wt. %. In a preferred embodiment, the fluorine-free material is used as a thickener. The fluorine-free material can also function as an additive to reduce the coefficient of friction. In this embodiment, the proportion of the fluorine-free material, based on the overall weight of the lubricating grease, is preferably from 10 to 55 wt. %, more preferably from 20 to 50 wt. %, in particular from 30 to 50 wt. %.
A subject matter of the invention is thus a lubricating grease comprising
Preferred embodiments of said lubricating grease comprise the preferred embodiments described within the scope of the invention mutatis mutandis.
In a further preferred embodiment, the fluorine-free material is used as an additive to reduce the coefficient of friction. The fluorine-free material can also function as a thickener. In this embodiment, the proportion of the fluorine-free material, based on the overall weight of the lubricating grease, is preferably from 1 wt. % to 10 wt. %, even more preferably from 5 wt. % to 7 wt. %, in particular from 1 wt. % to 5 wt. %.
It has been found that particularly consistent lubricants can be obtained using these proportions, which are comparable to the quantities generally used for PTFE.
According to the invention, the lubricating grease comprises 20 wt. % to 88 wt. %, preferably 30 wt. % to 88 wt. %, even more preferably 50 wt. % to 88 wt. %, in particular 60 wt. % to 88 wt. % of a base oil, based on the overall weight of the lubricating grease.
Preferably, the base oil is selected from the group consisting of esters, preferably dipentaerythritol esters, trimellitic acid esters, hemimellitic acid esters, pyromellitic acid esters, estolides, pentaerytritol esters, dimer acid esters, trimer acid esters, trimethylolpropane esters (TMP esters), dicarboxylic acid esters; ethers, preferably polyphenyl ethers, diaryl ethers, triaryl ethers, polyglycols, preferably homo- and/or copolymers of ethylene oxide, propylene oxide, 1,2-butylene oxide and/or tetrahydrofuran (THF), preferably started with monoalcohols, dialcohols and trialcohols, linear or branched perfluoropolyether oils (PFPE oils); synthetic hydrocarbons, preferably alkylated naphthalenes, polyalphaolefins (PAOs), metallocene polyalphaolefins (mPAOs); mineral oils, untreated and chemically modified vegetable oils, group III oils; gas-to-liquid (GTL) oils; reraffinates and recyclates, preferably obtained from mineral oils, group III oils, GTL oils and/or PAO, dimethyl silicone oils; arylated silicone oils, alkylaryl silicone oils, which can be used alone or in combination. Dimethyl silicone oil is also called polydimethylsiloxane (PDMS).
In a preferred embodiment of the invention, the base oil is selected from the group consisting of esters, preferably dipentaerythritol esters, trimellitic acid esters, hemimellitic acid esters, pyromellitic acid esters, estolides, pentaerytritol esters, dimeric acid esters, trimeric acid esters, TMP esters, dicarboxylic acid esters; ethers, preferably, diaryl ethers, polyglycols, preferably homo- and/or copolymers of ethylene oxide, propylene oxide, 1,2-butylene oxide and/or tetrahydrofuran (THF), preferably started with monoalcohols, dialcohols and trialcohols, synthetic hydrocarbons, preferably alkylated naphthalenes, polyalphaolefins (PAOs), metallocene polyalphaolefins (mPAOs); mineral oils, untreated and chemically modified vegetable oils, group III oils; reraffinates and recyclates, preferably obtained from mineral oils, group III oils, GTL oils and/or PAOs, dimethyl silicone oils, which can be used alone 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 ester, trimellitic acid ester, hemimellitic acid ester, pyromellitic acid ester, estolides, pentaerythritol ester, dimer acid ester, trimer acid ester, dicarboxylic acid ester; diaryl ether; polyglycols, preferably homo- and/or copolymers of ethylene oxide, propylene oxide, 1,2-butylene oxide and/or tetrahydrofuran (THF), preferably started with monoalcohols, dialcohols and trialcohols, synthetic hydrocarbons, preferably alkylated naphthalenes, polyalphaolefins (PAOs), metallocene polyalphaolefins (mPAOs); mineral oils, untreated and chemically modified vegetable oils, group III oils, dimethyl silicone oils, which can be used alone or in combination.
In a particularly preferred embodiment of the invention, the base oil is dimethyl silicone oil.
In a further preferred embodiment, the base oil has a kinematic viscosity, determined according to ASTM-D-7042, publication date September 2014, at 40° C. from 30 in mm2/sec to 2000 mm2/sec, even more preferably at 40° C. from 50 mm2/sec to 1200 mm2/sec, in particular at 40° C. from 50 mm2/sec to 400 mm2/sec.
In an also preferred embodiment of the invention, the base oil is selected from the group consisting of esters, preferably dipentaerythritol esters, trimellitic acid esters, hemimellitic acid esters, pyromellitic acid esters, estolides, pentaerytritol esters, dimeric acid esters, trimeric acid esters, TMP esters, dicarboxylic acid esters, each having a kinematic viscosity at 40° C., determined according to ASTM-D-7042, publication date September 2014, of 100 mm2/sec to 1200 mm2/sec; ethers preferably polyphenyl ether, diaryl ether, triaryl ether, linear or branched perfluoropolyether oils (PFPE oils), each having a kinematic viscosity at 40° C., determined according to ASTM-D-7042, publication date September 2014, of 20 mm2/sec to 1200 mm2/sec; polyglycols, preferably homo- and/or copolymers of ethylene oxide, propylene oxide, 1,2-butylene oxide and/or tetrahydrofuran (THF), preferably started with monoalcohols, dialcohols and trialcohols, in each case having a kinematic viscosity at 40° C., determined according to ASTM-D-7042, publication date September 2014, from 20 mm2/sec to 46000 mm2/sec; synthetic hydrocarbons, preferably alkylated naphthalenes, polyalphaolefins (PAOs), metallocene polyalphaolefins (mPAOs), each having a kinematic viscosity at 40° C., determined according to ASTM-D-7042, publication date September 2014, of 10 mm2/sec to 20000 mm2/sec; group III oils having a kinematic viscosity at 40° C., determined according to ASTM-D-7042, publication date September 2014, of 10 mm2/sec to 100 mm2/sec, dimethyl silicone oils, arylated silicone oils, preferably alkylaryl silicone oils, in particular methyl/aryl silicone oils and fully arylated silicone oils, each having a kinematic viscosity at 40° C., determined according to ASTM-D-7042, publication date September 2014, of 10 mm2/sec to 1200 mm2/sec and/or each having a kinematic viscosity at 25° C., determined according to DIN 53019, publication date 2008.09, of 20 to 2000000 mm2/sec, which can be used alone or in combination.
As explained above, in a preferred embodiment, the fluorine-free material is used as a thickener. The fluorine-free material can also function as an additive to reduce the coefficient of friction. In this embodiment, the lubricating grease can also have a further thickener that is different from the fluorine-free material used according to the invention. Preferably, the further thickener is selected from the group consisting of metal soaps, preferably metal simple soaps of the elements of the first and second main group of the periodic table, metal complex soaps of the elements of the first and second main group of the periodic table, in particular lithium soaps, lithium complex soaps, aluminum complex soaps, sodium complex soaps, calcium complex soaps, boron nitride, alkylated and/or arylated (oligo)ureas, wax, in particular polyethylene (PE), polypropylene (PP), polyamide (PA) wax, wherein the wax has a melting or decomposition point, measured according to DIN EN ISO 11357-1, publication date 2008.04, of higher than 100° C.; carbon black, graphite, metal sulphonate thickeners, in particular calcium sulphonate thickeners, metal chalcogenides, in particular molybdenum disulfide, tungsten disulfide, metal selenides, which can be used alone or in combination.
In a preferred embodiment, the further thickener is an (oligo)urea, in particular 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′-diisocyanatodi-phenyl, 4,4′-diisocyanato-3-3′-dimethylphenyl, 4,4-diisocyanato-3,3′-dimethylphenylmethane, which can be used alone 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, wherein R is an aryl, alkyl or alkylene rest having 2 to 22 carbon atoms and R′ is identical or different and is a hydrogen, an alkyl, alkylene or aryl rest, or with mixtures of amines and diamines.
In a further preferred embodiment, the further thickener is a calcium sulphonate thickener. Calcium sulphonate thickeners contain crystalline calcium carbonate in the form of calcite and calcium salts of acids, in particular aromatic sulphonic acids, most preferably alkyl benzene sulphonic acids, carboxylic acids, in particular stearic acid, 12-hydroxystearic acid, acetic acid, boric acid, and mixtures thereof.
In a further preferred embodiment, the further thickener is a metal soap, in particular a lithium soap and/or a lithium complex soap. A lithium soap is understood to mean lithium salts of monofunctional carboxylic acids. Particularly preferred are lithium salts of monofunctional carboxylic acids with 8 to 22 carbon atoms, even more preferably 14 to 20 carbon atoms. Particularly preferred lithium soaps are lithium salts of stearic acid, hydroxystearic acid, 12-hydroxystearic acid, monohydroxybenzoic acid, in particular salicylic acid and/or lithium salts of mixtures of the aforementioned acids. A lithium complex soap is understood to be mixtures of lithium salts of monofunctional carboxylic acids with lithium salts of dicarboxylic acids and/or tricarboxylic acids.
Preferably, the lithium complex soap comprises lithium salts of monofunctional carboxylic acids with 8 to 22 carbon atoms, more preferably 14 to 20 carbon atoms. Particularly preferably, the lithium complex soap includes lithium salts of stearic acid, hydroxystearic acid, 12-hydroxystearic acid, monohydroxybenzoic acid, in particular salicylic acid and/or lithium salts of mixtures of the aforementioned acids. Also particularly preferably, the lithium complex soap includes lithium salts of dicarboxylic acids with 2 to 20 carbon atoms, even 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 includes 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 further thickener is preferably present in a proportion from 3 wt. % to 30 wt. %, more preferably from 3 wt. % to 20 wt. % and in particular from 3 wt. % to 10 wt. %, in each case based on the overall weight of the lubricating grease.
As explained above, the fluorine-free material can also be used as an additive. In this embodiment, the lubricating grease preferably has a thickening agent that is different from the fluorine-free material used according to the invention.
Preferably, the thickening agent in this embodiment is selected from the group consisting of metal soaps, preferably metal simple soaps of the elements of the first and second main group of the periodic table, metal complex soaps of the elements of the first and second main group of the periodic table, in particular lithium soap, lithium complex soaps, aluminum complex soaps, sodium complex soaps, calcium complex soaps, boron nitride, alkylated and/or arylated (oligo)ureas, wax, in particular polyethylene (PE)-, polypropylene (PP)-, polyamide (PA)-wax, wherein the wax has a melting or decomposition point, measured according to DIN EN ISO 11357-1, publication date 2008.04, of higher than 100° C.; carbon black, graphite, metal sulphonate thickeners, in particular calcium sulphonate thickeners, metal chalcogenides, in particular molybdenum disulfide, tungsten disulfide, metal selenides, which can be used alone or in combination.
In a preferred embodiment, the thickening agent is an (oligo)urea, in particular 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′-diisocyanatodi-phenyl, 4,4′-diisocyanato-3-3′-dimethylphenyl, 4,4-diisocyanato-3,3′-dimethylphenylmethane, which can be used alone 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, wherein R is an aryl, alkyl or alkylene rest having 2 to 22 carbon atoms and R′ is identical or different and is a hydrogen, an alkyl, alkylene or aryl rest, or with mixtures of amines and diamines.
In a further preferred embodiment, the thickening agent is a calcium sulphonate thickener. Calcium sulphonate thickeners contain crystalline calcium carbonate in the form of calcite and calcium salts of acids, in particular aromatic sulphonic acids, most preferably alkyl benzene sulphonic acids, carboxylic acids, in particular stearic acid, 12-hydroxystearic acid, acetic acid, boric acid and mixtures thereof.
In a further preferred embodiment, the thickening agent is a metal soap, in particular a lithium soap and/or a lithium complex soap. A lithium soap is understood to be lithium salts of monofunctional carboxylic acids. Particularly preferred are lithium salts of monofunctional carboxylic acids with 8 to 22 carbon atoms, even more preferably 14 to 20 carbon atoms. Particularly preferred lithium soaps are lithium salts of stearic acid, hydroxystearic acid, 12-hydroxystearic acid, monohydroxybenzoic acid, in particular salicylic acid and/or lithium salts of mixtures of the aforementioned acids.
A lithium complex soap is understood to be mixtures of lithium salts of monofunctional carboxylic acids with lithium salts of dicarboxylic acids and/or tricarboxylic acids. Preferably, the lithium complex soap includes lithium salts of monofunctional carboxylic acids with 8 to 22 carbon atoms, more preferably 14 to 20 carbon atoms. Particularly preferably, the lithium complex soap includes lithium salts of stearic acid, hydroxystearic acid, 12-hydroxystearic acid, monohydroxybenzoic acid, in particular salicylic acid and/or lithium salts of mixtures of the aforementioned acids. Also particularly preferably, the lithium complex soap includes lithium salts of dicarboxylic acids with 2 to 20 carbon atoms, even 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 thickening agent is a combination of two or more of the aforementioned further thickeners.
Preferably, the thickening agent is a metal soap. Preferred metal soaps are the metal soaps described above in relation to the further thickener.
Preferably, the thickener is present in a proportion of 3 wt. % to 40 wt. %, more preferably from 6 wt. % to 30 wt. % and in particular from 8 wt. % to 25 wt. %, in each case based on the overall weight of the lubricating grease.
A subject matter of the invention is thus a lubricating grease comprising
Preferred embodiments of said lubricating grease comprise the embodiments described within the scope of the invention mutatis mutandis.
Preferably, the lubricating grease is a consistent lubricating grease. In a further preferred embodiment, the high-temperature lubricating grease is a lubricating grease of NLGI class 1 to 3, preferably 2, in accordance with DIN 51818, publication date 1981.12. In a further preferred embodiment, the lubricating grease has a worked penetration, measured in accordance with DIN-ISO 2137, publication date 12/2016, of 200 1/10 mm to 400 1/10 mm, preferably from 220 1/10 mm to 340 1/10 mm, even more preferably from 250 to 340 1/10 mm, in particular from 265 1/10 mm to 295 1/10 mm.
In a preferred embodiment of the invention, the lubricating grease comprises additives against wear, oxidation, corrosion and/or additives for reducing friction and/or improving the high-pressure characteristics, the pour point and/or the viscosity.
If used, the additives are preferably present in a proportion from 1 wt. % to 10 wt. %, even more preferably from 1 wt. % to 8 wt. %, and in particular from 1 wt. % to 5 wt. %, in each case based on the overall weight of the lubricating grease.
The antioxidants used are, in particular, antioxidants selected from the group comprising aromatic aminic antioxidants, such as alkylated phenyl-alpha-naphthylamine, dialkyl diphenylamine, aralkylated diphenylamine, sterically hindered phenols, such as butylhydroxytoluene (BHT), which can be used alone or in combination.
The wear protection agent is preferably selected from the group comprising amine-neutralized phosphates, alkylated and non-alkylated triaryl phosphates, alkylated and non-alkylated triaryl thiophosphates, zinc or Mo or W-dialkyl dithiophosphates, carbamates, thiocarbamates, zinc or Mo or W-dithiocarbamates, dimercapto-thiadiazole, which are used alone or in combination.
The corrosion protection agent is preferably selected from the group comprising additives based on calcium sulfonates, preferably “overbased” Ca-sulfonates with a base number (TBN) of 100 to 500 mg KOH/g, amine-neutralized phosphates, alkylated Ca-naphthalene sulfonates, oxazoline derivatives, imidazole derivatives, succinic acid half esters, N-alkylated benzotriazoles, benzotriazole which are used alone or in combination.
Preferred high pressure additives are selected from the group comprising thiophosphates, sulfurized compounds, preferably sulfurized fatty acid esters, alkylated polysulfides, which can be used alone or in combination.
Preferred additives for improving the pour point and/or viscosity are selected from the group comprising linear or branched, alkylated, acrylated and/or aliphatic polymers, copolymers, which can be used alone or in combination.
The invention also relates to a method for producing the lubricating grease according to the invention comprising a mixing of the following components:
Preferred embodiments for the method according to the invention comprise the embodiments described with reference to the lubricating grease according to the invention.
The invention also relates to the use of the lubricating grease according to the invention for lubricating tribological systems, in particular tribological systems in applications in which a wide usage temperature range, from below −60° C. to above 160° C. and/or from −60° C. to 160° C., is required.
In a preferred embodiment of the invention, the lubricating grease according to the invention is used to lubricate plain bearings, in particular chains, valves, fittings, actuators, antifriction bearings, and/or to drive production plants in the chemical industry.
In a particularly preferred embodiment of the invention, the lubricating grease according to the invention is designed as a high-temperature grease for antifriction bearing applications. In this context, a high-temperature grease for antifriction bearing applications is understood to be a grease which, following DIN 51825:2004-06, reaches its top usage temperature at 3000 rpm, 1500 N load and installation position B at a temperature of at least 160° C., e.g. 160° C. to 240° C. and/or at 160° C. to 200° C. The top usage temperature is achieved when at least 50% of a group of bearings (at least 5 test bearings) has achieved a running time of at least 100 h at the test temperature.
In a particularly preferred embodiment of the invention, the lubricating grease according to the invention is designed as a lubricating grease for antifriction bearing applications. In this context, a lubricating grease for antifriction bearing applications is understood to be a grease which, following DIN 51825:2004-06, reaches its top usage temperature at 3000 rpm, 1500 N load and installation position B in a temperature range of 100° C. to 160° C. and/or 120° C. to 160° C. The top usage temperature is achieved when at least 50% of a group of bearings (at least 5 test bearings) achieves a running time of at least 100 h at the test temperature.
A preferred embodiment of the invention comprises the use of the lubricating grease according to the invention for the lubrication of plain bearings, preferably fittings, in particular gas fittings, pneumatic cylinders, seals, valves, actuators, linear guides, regulating and control flaps in the intake manifold, couplings, screws, bolts, fittings, conveyor belts, chains for transport in freezing tunnels for the food industry and/or for driving production plants in the chemical industry. The plain bearings, antifriction bearings and/or production plants in the chemical industry are preferably operated at temperatures of −60° C. to 160° C. at least intermittently.
Preferred embodiments for the use according to the invention comprise the embodiments described with reference to the lubricating grease according to the invention.
The invention also relates to the use of the lubricating grease according to the invention for the lubrication of tribological systems which are in contact with foodstuffs, for example working apparatus in food processing containing gears, antifriction and plain bearings, such as chains for transportation in freezing tunnels and conveyor belts, pneumatic cylinders, seals. The invention also relates to the use of the grease according to the invention for the lubrication of tribological systems that are in contact with drinking water, such as valves and fittings, for gas and (drinking) water fittings; and/or for the lubrication of tribological systems in which an application spectrum in the temperature range from below −60° C. to above 160° C. is required and/or for the lubrication of components in the automotive industry which have antifriction or plain bearings, such as ball-type linear drives in automotive steering applications, actuators, transmissions, plastic transmissions, seals, seals in sliding sunroofs, brake boosters and/or linear guides.
Preferred embodiments for use according to the invention comprise the embodiments described with reference to the lubricating grease according to the invention.
The invention is explained in more detail below using experiments that do not limit the invention. Mixing at 1500 rpm for 10 min is carried out with a Hauschild DAC 700.1 FVZ SpeedMixer.
Six lubricating greases according to the invention are produced as follows:
Example grease 1: In a container, 9.0 g Lithium 12-hydroxystearate in 51.9 g PAO 6 of viscosity 30 mm2/sec at 40° C. is heated to a temperature of 205° C. under stirring, and cooled slowly. After the addition of 0.5 g of an aminic antioxidant Irganox L 150 and 2.1 g of disodium sebacate, the mixture is homogenized using a three-roll mill, 36.5 g of mica having an average particle size of D50=15 μm is added and stirred at 1500 rpm for 10 min. The mixture is homogenized again using a three-roll mill to obtain a lubricating grease of NLGI class 2 (worked penetration 280 1/10 mm).
Example grease 2: In a container, 9.0 g of Lithium hydroxystearate in 52.2 g of PAO 6 with a viscosity of 30 cst at 40° C. is heated to a temperature of 205° C. under stirring, and cooled slowly. After the addition of 0.5 g of an aminic antioxidant Irganox L 150 and 2.1 g of disodium sebacate, the mixture is homogenized using a three-roll mill, 36.2 g of zirconium hydrogen phosphate and mean particle size D50=1.7 μm are added and stirred at 1500 rpm for 10 min. The mixture is homogenized again using a three-roll mill to obtain a lubricating grease of NLGI class 1 (worked penetration 330 1/10 mm).
Example grease 3: In a container, 7.9 g of Lithium hydroxystearate in 45.3 g of PAO 6 of viscosity 30 cst at 40° C. are heated to a temperature of 205° C. under stirring, and cooled slowly. After the addition of 0.4 g of an aminic antioxidant Irganox L 150 and 1.8 g of disodium sebacate, the mixture is homogenized using a three-roll mill, 44.6 g of melamine monophosphate and mean particle size D50=10 μm are added and stirred at 1500 rpm for 10 min. The mixture is homogenized again using a three-roll mill to obtain a lubricating grease of NLGI class 1 (worked penetration 330 1/10 mm).
Example grease 4: In a container, 8.3 g of Lithium hydroxystearate in 48.0 g of PAO 6 of viscosity 30 cst at 40° C. are heated to a temperature of 205° C. under stirring, and cooled slowly. After the addition of 0.5 g of an aminic antioxidant Irganox L 150 and 1.9 g of disodium sebacate, the mixture is homogenized using a three-roll mill, 41.3 g of 1,3,5-triazine-2,4,6 (1H,3H,5H)-trithione and mean particle size D50=10 μm are added and stirred at 1500 rpm for 10 min. The mixture is homogenized again using a three-roll mill to obtain a lubricating grease of NLGI class 2 (worked penetration 280 1/10 mm).
Comparative grease 5 (comparison example): In a container, 9.1 g of Lithium hydroxystearate in 53.3 g of PAO 6 of viscosity 30 cst at 40° C. are heated to a temperature of 205° C. under stirring, and cooled slowly. After the addition of 0.7 g of an aminic antioxidant Irganox L 150 and 1.9 g of disodium sebacate, the mixture is homogenized using a three-roll mill, 35.0 g of PTFE micropowder having a melting point of 330° C. and an average particle size of D50=4 μm is added and stirred at 1500 rpm for 10 min. The mixture is homogenized again using a three-roll mill to obtain a lubricating grease of NLGI class 2 (worked penetration 290 1/10 mm).
Example grease 10: In a container, 8.1 g Li-12-hydroxystearate in 47.6 g PAO 6 of viscosity 30 mm2/sec at 40° C. is heated to a temperature of 205° C. under stirring, and cooled slowly. After adding 0.6 g of an aminic antioxidant Irganox L 150 and 1.7 g of disodium sebacate, the mixture is homogenized using a three-roll mill, 42.0 g of PPS micropowder having a melting point of 280° C. and an average particle size of D50=5 μm is added and stirred at 1500 rpm for 10 min. The mixture is homogenized again using a three-roll mill to obtain a lubricating grease of NLGI class 2 (worked penetration 295 1/10 mm).
Example grease 11: In a container, 7.9 g of Lithium hydroxystearate in 46.2 g of PAO 6 of viscosity 30 cst at 40° C. are heated to a temperature of 205° C. under stirring, and cooled slowly. After adding 0.6 g of an aminic antioxidant Irganox L 150 and 1.7 g of disodium sebacate, the mixture is homogenized using a three-roll mill, 43.6 g of PEEK micropowder having a melting point of 340° C. and an average particle size of D50=10 μm is added and stirred at 1500 rpm for 10 min. The mixture is homogenized again using a three-roll mill to obtain a lubricating grease of NLGI class 2 (worked penetration 295 1/10 mm).
The tribological properties of the lubricating greases produced in Example 1 are examined on the Tannert sliding friction test rig. This is a testing device commonly used in tribotechnology, described for example in T. Mang (Editor), Encyclopedia of Lubricants and Lubrication, Springer, Berlin, Heidelberg 2014, and is used to test the frictional behavior during slow oscillating movements. A sliding tongue of ST37 steel greased with 0.5 g is oscillated back and forth at room temperature between two cylindrical rollers (100Cr6 steel, diameter 10 mm, length 10 mm) in linear geometry at a speed of 0.243 mm/s. In the first cycle, a normal force of 100 N is applied. After each movement cycle of 200 mm, the normal force is increased by 50 N until stick-slip occurs or the maximum load of 1200 N is reached. At the same time, the average friction force is determined continuously over each movement cycle. The tests are preferably carried out at 25° C.
As can be seen from
The rheological properties of the lubricating greases produced in Example 1 are determined on the Anton Paar MCR 300 rheometer in accordance with DIN 53019 at a test temperature of 25° C. and a shear rate of 300 s−1. The shear viscosities determined after a measuring period of 90 s are compared with the shear viscosity of the comparative grease containing PTFE:
According to Table 1 below, it can be seen surprisingly that the shear viscosity of the zirconium hydrogen phosphate-containing lubricating grease 2 according to the invention is only about half that of the PTFE-containing comparative grease 5. The melamine monophosphate-containing lubricating grease 3 according to the invention also has a significantly lower shear viscosity than the PTFE-containing comparative grease.
The lubricating greases 6 to 8 according to the invention and the comparative grease 9 are produced as follows:
Example grease 6: In a container, 71.5 g of perfluoropolyether oil consisting of perfluoropropylene oxide as a monomer, available as Aflunox 400 V of viscosity 430 mm2/sec at 40 cst is mixed with 26.5 g PPS micropowder having a melting point at 280° C. and an average particle size D50=5 μm and 2 g disodium sebacate as an anti-corrosion additive at 1000 rpm for 5 min in a speed mixer and homogenized using a three-roll mill, to obtain a lubricating grease of NLGI class 2-3 (worked penetration 250 1/10 mm).
Example grease 7: In a container, 71.7 g perfluoropolyether oil type Aflunox 400 V of viscosity 430 mm2/sec at 40 cst is mixed with 26.3 g PEEK micropowder having a melting point at 340° C. and an average particle size D50=10 μm and 2 g disodium sebacate at 1000 rpm for 5 min in a speed mixer and homogenized using a three-roll mill, to obtain a lubricating grease of NLGI class 2 (worked penetration 280 1/10 mm).
Example grease 8: In a container, 82.4 g of perfluoropolyether oil type Aflunox 400 V of viscosity 430 mm2/sec at 40 cst is mixed with 15.6 g of 1,3,5-triazine-2,4,6 (1H,3H,5H)-trithione of average particle size D50=10 μm and 2 g of disodium sebacate at 1000 rpm for 5 min in a speed mixer and homogenized using a three-roll mill, to obtain a lubricating grease of NLGI class 2 (worked penetration 275 1/10 mm).
Comparative grease 9 (comparison example): In a container, 70.0 g perfluoropolyether oil type Aflunox 400 V of viscosity 430 mm2/sec at 40 cst is mixed with 28.0 g PTFE micropowder having a melting point at 330° C. and an average particle size D50=4 μm and 2 g disodium sebacate at 1000 rpm for 5 min in a speed mixer and homogenized using a three-roll mill, to obtain a lubricating grease of NLGI class 2 (worked penetration 275 1/10 mm).
Comparative grease 12 (comparative example): In a container, 72.0 g of perfluoropolyether oil is mixed with 28.0 g of PTFE micropowder having a melting point at 330° C. and an average particle size D50=4 μm and 2.0 g of disodium sebacate at 1000 rpm for 5 min and homogenized using a three-roll mill, to obtain a lubricating grease of NLGI class 2 (worked penetration 280 1/10 mm).
As Table 2 shows, the example greases according to the invention exhibit significantly lower oil separation at 100° C. and 200° C. with comparable low-temperature behavior (flow pressure results), so that the perfluoropolyether oil is better retained in the grease. In the high-temperature service life test (FE 9), example grease 6 shows a significant extension of the L 50 service life and example grease 7 a significantly improved extension of the L 10 service life.
Example grease 13: In a container, 72.0 g of perfluoropolyether oil consisting of perfluoropropylene oxide as a monomer, available as Aflunox 400 V of viscosity 430 mm2/sec at 40 cst is mixed with 26.0 g of 1,3,5-triazine-2,4,6 (1H,3H,5H)-trithione, particle size D50=10 μm, and 2 g disodium sebacate as an anti-corrosion additive, at 1000 rpm for 5 min in a speed mixer and homogenized using a three-roll mill to obtain a lubricating grease of NLGI class 2 (worked penetration 259 1/10 mm).
Example grease 14: In a container, 71.0 g of perfluoropolyether oil consisting of perfluoropropylene oxide as monomer, available as Aflunox 400 V of viscosity 430 mm2/sec at 40 cst is mixed with 27.0 g of melamine phosphate, particle size D50=6.7 μm, and 2 g disodium sebacate as an anti-corrosion additive at 1000 rpm for 5 min in a speed mixer and homogenized using a three-roll mill to obtain a lubricating grease of NLGI class 2 (worked penetration 271 1/10 mm).
The greases according to the invention show a reduction in oil separation by half at 100° C. compared to the comparative grease; at 200° C. there is only a slight increase. The low-temperature behavior (flow pressure) is to be regarded as essentially equivalent. The friction behavior (Tannert) is significantly improved. Example grease 13 exhibits improved service life in the FE 9 test. Example grease 14 also very reliably fulfills the requirements of the service life test (FE 9).
The lubricating greases 15 to 18 according to the invention, containing fluorine-free materials of group B3 and partially fluorine-free materials of group B6, are produced. The procedure is as follows: The silicone oil is placed in a container and heated to 120-130° C. under stirring. Then the Aerosil, dimethyl dichlorosilane is modified, BET surface area approx. 110 m2/g, is added, and the mixture is stirred for 1 hour. After cooling, the silicone oil/Aerosil preparation is mixed with the other formulation components according to the table and stirred at 1500 rpm for 10 min. The mixtures are homogenized using a three-roll mill to obtain the example greases listed in the table.
The tribological properties of the lubricating greases produced in Example 4 are determined on the Tannert sliding friction test rig. The coefficients of friction obtained are compared with the coefficients of friction of a PTFE-containing grease (comparative grease 9):
As can be seen in
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/EP2022/082624, 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 2023/094322 A1 under PCT Article 21(2).
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/082624 | 11/21/2022 | WO |
