Production of thickened lubricating greases with polyurea having improved lubricating properties.

Abstract

The invention relates to a method for producing a polyurea-thickened lubricating-grease intermediate product, consisting of or comprising the following steps: a) providing at least one first thickener precursor; b) providing at least one second thickener precursor; c) metering the provided thickener precursors from steps a) and b) into a mixing chamber, optionally additionally adding at least one additive; d) mixing the at least two thickener precursors and the optional at least one further additive in the mixing chamber, and reacting the two thickener precursors; e) obtaining at least one polyurea-thickened lubricating-grease intermediate product, wherein, in order to achieve cooling during the reaction in step d), at least one of the thickener precursors provided in steps a) and b) and / or the at least one additive from step c) has a temperature in a range of 0°C to less than 40°C, preferably in a range of 10°C to less than 40°C.

Description

1 / 25 “PRODUCTION OF POLYUREA-THICKENED LUBRICATING GREASES WITH IMPROVED LUBRICATING PROPERTIES”

[001] The present invention is in the field of the production of lubricating greases, especially the production of polyurea-thickened lubricating greases. The invention provides a process for the production of the input stages of lubricating greases, as well as for the production of the final lubricating grease. In addition, the use of a device for the production of a lubricating grease according to the invention and a lubricating grease according to the invention is provided.

[002] For tribosystems, as employed in many technical applications, it is important to use lubricants to reduce friction and wear on the contact surfaces of moving parts. In this case, depending on the field of application, lubricants of different consistencies can be used. Lubricating oils have a liquid and fluid consistency, while lubricating greases have a semi-solid to solid consistency – often gelatinous.

[003] A characteristic of a lubricating grease is that a liquid oil element is received and retained by a thickening component. The gelatinous nature of a lubricating grease and its property of being easily deformable with plasticity and spreading capacity, together with the property of being adhesive, causes the lubricating grease to wet the lubrication point and the lubricating effect to unfold on the tribologically stressed surfaces.Lubricating greases comprise, in addition to additives, essentially a thickening agent, which is present in a base oil.

[004] Among the most important rheological properties of a lubricating grease are its consistency or yield point, the avoidance of post-hardening and excessive oil separation under heat and mechanical treatment, as well as stable behavior. Petition 870250081392, dated 10 / 09 / 2025, page 8 / 48 2 / 25 viscosity temperature and cross-viscosity behavior. To create a high-value lubricating grease, based on application requirements, many practical experiments are necessary.

[005] In the field of lubricating greases, it is important that the thickener is present distributed in small and uniform particle sizes and, at the same time, that the thickener molecules are produced with high selectivity and very reduced secondary chemical reactions, in order to produce lubricating greases that are stable during aging and compatible with the material. Lubricating greases produced in this way lead to extended bearing life, greater storage stability, very good noise behavior, less harm to the health of users and better environmental compatibility.

[006] The production of polyurea-thickened lubricating greases is a central research topic. Thus, document GB 776548A discloses a process for producing metallic soap-thickened lubricating greases, which can also be applied to polyurea greases by the principle of processes in which the reaction mixture is strongly sheared in a reaction zone. Alternatively, a reaction mixture can be circulated, totally or partially, with the addition of a reagent between a sheared and an unsheared zone.

[007] Document EP 1062307B1 discloses a batch production process which describes, in addition to soap-thickened greases, also polyurea lubricating greases. For this, a polyurea lubricating grease is conducted, during its production, in circulation via a harmonizing device in accordance with verification using the SKF BeQuiet method.

[008] Document EP 1322732B1 discloses the discontinued production of a low-noise lubricating grease with a size of Petition 870250081392, dated 10 / 09 / 2025, p. 9 / 48 3 / 25 of the thickener particles are defined as 95% smaller than 100 μm. To achieve this, the thickener is initially produced through the reaction of diisocyanates and amines. Then, a mixture of the thickener and a base oil is sheared for a period of time at a temperature of 35°C to 55°C to the desired particle size, then heated to a temperature of 150°C to 175°C and subsequently cooled to a temperature of 25°C to 105°C. Finally, the grease is milled to obtain a homogeneous grease.

[009] US patent 2010 / 0029526A1 discloses the production of low-noise polyurea lubricating greases through the sequential addition of two or more oil-predisposed amines to an oil-predisposed isocyanate found in the reactor.

[0010] Document EP1322732B1 discloses the continuous production of polyurea lubricating greases through “Reactive Injection Molding”. In this case, the amine and isocyanate reaction partners are diluted / dissolved separately in a solvent and then, under high pressure, injected simultaneously into a high-pressure injection unit, where the thickener is formed.

[0011] Document US8703671B2 discloses the continuous production of polyurea lubricating greases using a twin-screw (reactive) extruder. The characteristic, in this case, is that reaction components, such as isocyanates and amines, are added at various points in the extruder, while at other points in the extruder, base oil can be dosed. The feeding of reaction components pre-dissolved in oil is also described. In addition, temperatures in the individual reaction zones ("mixing-cooling zone") are described.

[0012] EP3031888B1 describes the production of polyurea lubricating greases by simultaneously introducing oil-pre-dissolved amines and oil-dissolved isocyanates at a shear point with a defined shear rate greater than 1021 / s. In this case Petition 870250081392, dated 10 / 09 / 2025, page 10 / 48 4 / 25 The shear rate is defined as the coefficient of the reaction rate between a rotating internal component and the inner wall of the shear cell and the smallest distance between these two components. The shearing of the reaction components pre-dissolved in oil occurs within 15 min after their joining. The isocyanate-amine reaction occurs at 60-120°C.

[0013] Document EP3255130A1 describes the production of a low-noise lubricating grease based on at least one aromatic amine and other amines according to the process in document EP 3031888, in which this is applied in such a way that the average particle size of the lubricating grease thickener produced accordingly has an arithmetic mean of <1.6 μ. The determination of the average particle size is carried out according to the static light scattering method.

[0014] Document EP 3150688 B1 describes the production of an isocyanate-based lubricating grease and a mixture of alicyclic and aliphatic amines according to process EP3031888. The noise requirements for the correspondingly produced lubricating grease are a “Peak High 32-64s of < 1.5 and a Level High 32-64s of < 10°C” and are defined via the FAG method (also known as ISO 21250-3 “Method MQ”).

[0015] Document JP 201711519A describes a special embodiment of the Rotor / Stator shear cell mentioned in EP 3031888, in which, by varying the width and shear gap, the shear rate can be adjusted for oil-predisposed amines and oil-predisposed isocyanates, independently of the number of rotations of the rotating component.

[0016] The tested technique does not lead to the reaction temperature playing an important role in the quality of the lubricating grease obtained. The currently known production processes for greases Petition 870250081392, dated 10 / 09 / 2025, page 11 / 48 5 / 25 Polyurea lubricants describe either continuous production processes, which can be used in the widely used stirred reactors for batch production of lubricating greases, or discontinuous processes, in which no solution has been found for the problem of shear heating that occurs at high shear rates, and the exothermic reaction of amines, alcohols and isocyanates. This leads to the formation of undesirable secondary or decomposition chemicals in thickener synthesis and, therefore, to disadvantageous lubricating grease properties.

[0017] Thus, when a temperature-conditioned dissociation of the urea group occurs, regressively formed free resins can lead to high compatibility with synthetic material and skin compatibility. Free amines can also represent a high odor nuisance. Free amines also represent a toxicological risk to the user's health. In addition, a high reaction temperature could eventually cause easily volatile amines or alcohols (such as cyclohexylamine / cyclohexanol) not yet reacted with isocyanate to evaporate and thus not lead to the desired polyurea thickener and its properties (e.g., thickening capacity).It could also occur that, due to very high temperatures and possibly residual moisture present in oils, isocyanates that have not yet reacted with amines and alcohols decompose equally into free aromatic amines via carbamic acid formed intermediately and subsequent decarboxylation, which, as described above, brings with it a series of disadvantages. Free isocyanates also represent a toxicological risk to the health of users. Furthermore, a possible oligomerization of isocyanates (formation of urethdione, formation of isocyanates) or the formation of biride oligomers or allophthalate oligomers could lead to reduced thickening capacity and a... Petition 870250081392, dated 10 / 09 / 2025, page 12 / 48 6 / 25 High thermal and oxidative aging of lubricating greases. Free amines, alcohols or isocyanates often lead, according to the invention, to unintentional post-solidification of polyurea lubricating greases during storage or application.

[0018] Therefore, the objective of the present invention was to provide a process for producing a polyurea-thickened lubricating grease, which has high quality and aging stability, as well as limiting the formation of secondary products in the thickener production step.

[0019] This objective was achieved, according to the invention, in a first aspect, by providing a process for producing at least one polyurea-thickened lubricating grease intermediate product, consisting of or comprising the following steps: a) provision of at least one thickening precursor; b) provision of at least one thickening precursor; c) Dosing of the two precursors obtained from steps a) and b) in a mixing chamber, optionally with the addition of at least one additive; d) mixing of the two thickening precursors as well as, optionally, at least one other additive in the chamber and mixing and reaction of the two thickening precursors; (e) obtain at least one intermediate product of lubricating grease thickened with polyurea; wherein, in order to achieve cooling during the reaction in step d), at least one of the thickening precursors provided in steps a) and b) and / or said at least one additive from step c), a temperature in a range of 0°C to less than 40°C, preferably in a range of 10°C to less than 40°C. Petition 870250081392, dated 10 / 09 / 2025, page 13 / 48 7 / 25

[0020] The present invention generally relates to the production of lubricating greases based on various base oils and thickeners in urea and / or urethane molecules with aliphatic, cycloaliphatic and aromatic hydrocarbon groups. Corresponding lubricating greases are called polyurea or polyurethane greases, due to the presence of several urea or urethane groups at the same time, or also polyurea / polyurethane lubricating greases as a mixed form. As a generic term, polyurea lubricating grease or polyurea-thickened lubricating grease is generally used.

[0021] An “intermediate lubricating grease product” within the scope of the present invention is a product that forms the basis for a lubricating grease, but is further processed so that it can be used in grease-lubricated tribosystems. The intermediate lubricating grease product is usually a thickener that may already be present along with at least one base oil and / or at least one additive and is transformed into a final product through other process steps, such as, for example, heating and / or grinding. In addition, the intermediate lubricating grease product or thickener may preferably be a polyurea thickener, which is then transformed into a final product of polyurea-thickened lubricating grease with the addition of other base oils and other additives, in other process steps.

[0022] The thickener precursors provided in steps a) and b) are edutums which, in the mixing and reaction step d), react to form the thickener or to form the intermediate product of lubricating grease. They are preferably amines and / or alcohols and isocyanates as described below.

[0023] The additive added in step c) is an optional component in the production of lubricating grease and may be added to improve or achieve certain properties of the lubricating grease. Petition 870250081392, dated 10 / 09 / 2025, page 14 / 48 8 / 25

[0024] In one embodiment, the intermediate product of lubricating grease is a polyurea thickener derived from reaction products from amines and isocyanates. According to one embodiment, the polyurea thickener can be obtained as a reaction product of diisocyanates with C6- to C20 hydrocarbyl monoamines. However, reaction products of monoisocyanates, possibly additionally diisocyanates, with diamines may also be present. The polyurea thickeners preferably do not have a polymeric character, but rather, for example, dimer, trimer, tetramer or other oligomers. In addition to polyisocyanates, R-NCO type isocyanates (monoisocyanate) may also be used, where R represents a hydrocarbon residue with preferably 5 to 20 carbon atoms.

[0025] Preferably, di-ureas are obtained from di-isocyanates and monoamines or tetraureas are obtained from di-isocyanates, monoamines and diamines, respectively as defined above. In a particularly preferred manner, di-ureas are based on 4,4'-diphenylmethanediisocyanate (MDI) or toluene-2,4-diisocyanate (TDI) and primary aliphatic, aromatic and / or cyclic monoamines or tetraureas based on MDI or TDI and aliphatic, aromatic and / or cyclic mono- and diamines.

[0026] Step d), in which the two thickener precursors provided in steps a) and b) are mixed together, is responsible for producing the intermediate lubricating grease product, preferably the polyurea thickener. For this, an amine provided preferably and / or an alcohol provided react with an isocyanate exothermically to form urea or urethane.

[0027] The desired concentrations of urea / urethane molecules and unwanted byproducts that arise from the reaction of polyurea thickeners depend considerably on their reaction rates and equilibrium position. The position of Petition 870250081392, dated 10 / 09 / 2025, page 15 / 48 9 / 25 The equilibrium shifts towards the products due to the exothermic nature of the reactions. The reaction rate depends on the reaction kinetics and the transport of substances. The reaction kinetics increase with increasing temperature. The transport of substances depends considerably on the concentration of the edutums and the flow behavior (e.g., mixing / viscosity) and is thus also directly linked to temperature. As a rule, reactions with high reaction kinetics are limited by substance transfer, while substance transfer in kinetically limited reactions is often of less importance. The kinetics of urea / urethane formation through the reaction of amines / alcohols with isocyanates is very high. Therefore, it is more limited by substance transfer, which is why shearing is frequently performed during the reaction in the state of the art.The kinetics of undesirable side reactions are slow relative to the urea formation reaction and, therefore, are often kinetically limited. Increasing the reaction temperature increases the kinetics of side reactions, but the urea / urethane formation reaction is not significantly altered by limiting the transfer of matter. Therefore, increasing the reaction temperature leads to a higher formation of byproducts.

[0028] It has been surprisingly found, according to the invention, that the emergence of secondary products can be limited by adding at least one of the thickening precursors and / or at least one additive at a temperature between 0°C and less than 40°C, preferably from 10°C to less than 40°C, especially preferably in a range of 10°C to less than 35°C. This is especially surprising since, in the prior art, for temperature control, especially in a stirred reactor, the reactor shell is cooled. This cooling via the reactor shell, however, is not sufficient to adjust the temperature in the reactor in such a way that the Petition 870250081392, dated 10 / 09 / 2025, page 16 / 48 10 / 25 formation of secondary products is minimized. Insufficient cooling via the reactor casing should be observed, especially when the thickening effect of the lubricating grease intermediate product is employed and heat transfer by convection is greatly reduced. Unlike the prior art described above, which often does not contain information regarding the influence of temperature or cooling, a particularly advantageous process is defined according to the invention across the indicated temperature range.

[0029] Preferably, in step c) an additive is added cooled to a temperature of 0°C to 40°C, preferably to a temperature of 10°C down to less than 40°C, and especially preferably to a temperature of 10°C down to less than 35°C. It is especially preferred that the additive be a cooled base oil.

[0030] Preferably, the said at least one additive may be added at a temperature below 0°C in step d), to achieve cooling. Preferably, with addition at a temperature below 0°C, the formation of condensation moisture is avoided by means of measures known to a person skilled in the art, for example, by the use of a dry atmosphere or inert gas.

[0031] Preferably, the present invention relates to a process according to the invention, in which the first thickener precursor provided in step a) is selected from the group consisting of primary amines, preferably monoamino-hydrocarbyl-, di- or polyamino-hydrocarbyl compounds with 6 to 20 carbon atoms or alcohols with hydrocarbyl- or hydrocarbylene groups with 6 to 20 carbon atoms, or mixtures thereof, wherein the first thickener precursor is present as pure matter or as a mixture with at least one base oil.

[0032] Suitable amines as a first thickener precursor Petition 870250081392, dated 10 / 09 / 2025, p. 17 / 48 11 / 25 are mentioned, for example, in document EP 0508115 A1. Suitable alcohols may also have hydrocarbyl- or hydrocarbylene groups, preferably with 6 to 10 carbon atoms, especially 6 to 18 carbon atoms. The hydrocarbylene group preferably has aliphatic groups, especially alkyl or alkylene groups. Aromatic groups may also be used. They may be monoalcohols, diols or polyols. Preferably they are monoalcohols and D-alcohols, especially monoalcohols with a chain length of 6 to 18 carbon atoms.

[0033] Base oil can be classified as mineral oil or synthetic oil. Mineral oils include, for example, naphthene-based mineral oils and paraffin-based mineral oils, according to API Group I classification. Chemically modified aromatic or low-sulfur mineral oils with a small percentage of saturated compounds and improved viscosity / temperature behavior compared to API Group I oils, classified according to API Groups II and III, are also suitable.

[0034] Synthetic oils are understood to be especially polyethers, esters, polyalphaolefins, polyglycols and alkylaromatics and their mixtures, as well as silicone oils. The polyether compound may have free hydroxyl groups, but may also be etherified or esterified and / or produced from a starting compound with one or more hydroxyl and / or carboxyl groups (-COOH). Polyphenylethers, possibly alkylated, are also possible as single components or, better yet, as mixture components. Suitablely employable are esters of a di-, tri- or tetracarbolic acid, with or in mixture with C2-C22 alcohols, adipic acid ester, sebacic acid, trimethylolpropane, neopentyl glycol, pentaerythrite or dipentaerythrite present with saturated or unsaturated C2 to C22 carbolic acid, branched Petition 870250081392, dated 10 / 09 / 2025, p. 18 / 48 12 / 25 or unbranched, aliphatic, C18-dimer acid ester with C2 to C22 alcohols, complex ester, as individual components or in a mixture.

[0035] Furthermore, preferably the invention relates to a process such that said second thickener precursor provided in step b) is selected from the group consisting of: isocyanates, preferably mono- and / or poly-isocyanates with 5 to 20, especially preferably 6 to 15 carbon atoms, or mixtures of the aforementioned, wherein the second thickener precursor is present as a pure substance or as a mixture of at least one base oil.

[0036] As an isocyanate component (second thickener precursor), mono- and / or poly-isocyanates are suitable, wherein the poly-isocyanates are preferably hydrocarbons with two isocyanate groups. Isocyanates have 5 to 20, preferably 6 to 15 carbon atoms and preferably contain aromatic groups.

[0037] Preferably, within the scope of the present invention is a process in accordance with the invention, wherein said at least one additive is selected from the group consisting of base oils, volatile hydrocarbons, cooled or liquefied gases, amines, alcohols, isocyanates, antioxidants, wear protection agents, corrosion protection agents, detergents, dyes, lubrication enhancers, adhesion enhancers, viscosity additives, friction reducers, high-pressure additives or metal deactivators, simple and / or complex soaps, preferably present as lithium, sodium, magnesium, calcium, aluminum or titanium soaps, water or a mixture thereof.

[0038] These soaps can be added either as additives or, alternatively, formed during the in situ production of greases. Preferably, the intermediate product of lubricating grease thickened with polyurea, or the polyurea thickener and the soap thickener or complex, is used in common and further processed for Petition 870250081392, dated 10 / 09 / 2025, page 19 / 48 13 / 25 to form a final product, wherein lithium soaps, aluminum soaps or aluminum complex soaps, calcium sulfate or calcium sulfate complex soaps, calcium soaps or calcium complex soaps are especially preferred, preferably in a mixing ratio of 10:1 to 1:10, especially 5:1 to 1:5 (respectively mass : mass). Soap or complex soap thickeners and polyurea thickeners are then employed, preferably together at 5 to 25% by weight relative to the polyurea-thickened lubricating grease (final product), wherein the polyurea-thickened lubricating grease intermediate product or the polyurea thickener is employed at least at 1% by weight, preferably at least at 1.5% by weight, respectively relative to the polyurea-thickened lubricating grease (final product).

[0039] Preferably, solid lubricants may be used as additives, such as polymer powder, preferably polyamide, polyimide or PTFE, melamine cyanide, graphite, metal oxides, boron nitride, silicates, for example, magnesium silicate hydrate (talc), sodium tetraborate, potassium tetraborate, metal sulfides such as, for example, molybdenum sulfide, tungsten sulfide or sulfides in mixtures based on tungsten, molybdenum, bismuth, tin and zinc, aromatic salts, for example, of alkali and alkaline earth metals, such as, for example, calcium carbonate, sodium and calcium phosphate. Also preferably, soot or other carbon-based solid lubricating substances, such as, for example, nanotubes, may be added as additives.Similarly, lignin derivatives, such as alkaline or alkaline earth sulfonates, especially calcium lignin sulfonates, can be used to achieve specific properties, for example, 2 to 15% by weight (according to document WO2011095155A1 or US 8507421 B2).

[0040] In addition, additives may be added Petition 870250081392, dated 10 / 09 / 2025, page 20 / 48 14 / 25 organic carbonates, which improve the service properties of polyurea-thickened lubricating greases according to the invention, as well as improving the compatibility of polyurea-thickened lubricating greases with fluorinated elastomers through the use of organic carbonates. The organic carbonates preferably have 4 to 8 carbon atoms. The residues or component parts of the organic carbonates are hydrocarbons (apart from the carbonate group itself), i.e., the carbonate is not substituted by a heteroatom. Preferably they are cyclic carbonates, especially with 4 to 8, especially 4 or 5 carbon atoms. The organic cyclic carbonate can be added as an additive to the polyurea-thickened lubricating grease according to the invention during production, but preferably after manufacturing the intermediate product of polyurea-thickened lubricating grease in a cooling phase.

[0041] Other additives, which may preferably be added within the scope of the present invention, are preferably selected from: • primary oxidizing agents, such as amine compounds (e.g., alkylamine or 1-phenylaminonaphthalene), aromatic amines, such as phenylnaphthylamines or diphenylamines, or polymeric hydroxyquinolines (e.g., TMQ), phenolic compounds (e.g., 2,6-di-tert-butyl-4-methylphenol), zinc dithiocarbamate, or zinc dithiophosphate; • Antioxidants such as phosphites, for example, tris(2,4-di-tert-butylphenylphosphite) or bis(2,4-di-tert-butylphenyl)-pentaerythritol diphosphate or thio ether (for example, cresol thioether); • High-pressure additives and / or wear protection additives, such as sulfur or organic sulfur compounds, for example, polysulfide or sulfur olefins, superbasic calcium sulfonates, thiophosphates, phosphorus compounds, for example, phosphates Petition 870250081392, dated 10 / 09 / 2025, page 21 / 48 15 / 25 alkyl groups neutralized with amine; • Inorganic or organic boron compounds, zinc dialkyl dithiophosphate, organic bismuth compounds; thiophosphonates such as triphenylthiophosphate, phosphonates (phosphites) such as dioctyl thiophosphate, alkyl sulfonates, thiocarbanates such as methylene-bis(dibutyldithiocarbamates) and dithiocarbamates; Substances that improve "oiliness," such as polyols, C2 to C6 fatty acids, fatty acid esters, or animal or vegetable oils; Anticorrosive agents such as sulfonates, for example, petroleum sulfonate, di-nonyl-naphthalene sulfonate or sorbitan ester; calcium sulfonates, magnesium sulfonates, sodium sulfonates, calcium and sodium naphthalene sulfonates, sulfonic acid esters, disodium sebacate, calcium salicylates, amine phosphate, succinates; Metal deactivators such as benzotriazoles, for example, methylbenzyltriazoldialkylamine, sterically inhibited phenols, sodium nitrite: • viscosity improvers, such as polymethacrylate, polyisobutylene, oligodec-1-enes, polystyrenes; • friction reducers partially possessing wear-protective properties, such as organomolybdenum complexes (OMCs), molybdenum dialkyl dithiophosphates, molybdenum dialkyl dithiocarbamates, especially molybdenum di-n-butyl-dithiocarbamate and molybdenum dialkyl dithiocarbamate (Mo: m2nSn(dialkylcarbamate)2 with m = 0 to 3 and n = 4 to 1), zinc dithiocarbamate or zinc dithiophosphate; or a three-nucleus molybdenum compound, which corresponds to the formula MosSkLnQz in which L are independently selected ligands, which have organic groups with carbon atoms, as they are Petition 870250081392, dated 10 / 09 / 2025, page 22 / 48 16 / 25 disclosed in document US 617203 B1, to make the compound soluble or dispersible in oil, where n ranges from 1 to 4, k from 4 to 7, Q is selected from the group of neutral electron-donating compounds, consisting of amines, alcohols, phosphines and ethers, ez is in the range of 0 to 5 and comprises non-stoichiometric values ​​(compare DE 102007048091); • organic acids, such as isostearic acid, functional polymers, such as oleylamides, polyether and amide-based organic compounds, for example, tetra-decylene glycol-alkylpolyethylene glycol ether, PIBSI (polyisobutylenesuccinic acid imide), PIBSA (polyisobutylenesuccinic acid anhydride), partial glycerides, dialkyl hydrogen phosphonate, alkyl succinate.

[0042] A process according to the invention is also preferred, in which cooling of the reaction in step d) is further achieved by the fact that evaporating components are added as additives in step c).

[0043] When using components that evaporate, cooling occurs through the use of the enthalpy of evaporation of these components. Preferably, the boiling point of this component is below the reaction temperature that matches the two thickening precursors.

[0044] Still preferable within the scope of the present invention is a process according to the invention, in which a cooling of the reaction in step d) occurs further by the fact that sublimed components are added as additives in step c).

[0045] Preferably, the process according to the invention is such that the base oil has a kinematic viscosity of 12 to 2500 mm2 / s, preferably 30 to 500 mm2 / s at a temperature of 40°C.

[0046] Within the scope of the present invention, it is also preferred that Petition 870250081392, dated 10 / 09 / 2025, page 23 / 48 17 / 25 the mixing in step d) in the mixing chamber occurs under shear.

[0047] Preferably, when sheared in the mixing chamber, poorly soluble or insoluble eductuaries in base oil can be transformed into an intermediate product of lubricating grease. Preferably, such eductuaries can be transformed by shearing, as described herein, which are poorly soluble or insoluble in base oil at temperatures below 20°C.

[0048] In the reaction to form the intermediate product of polyurea-thickened lubricating grease from amines (or alcohols) and isocyanate, di- or tetra-urea can be formed, for example, regardless of the raw materials chosen and their stoichiometry.

[0049] In a particularly preferred manner, shearing occurs with a shear rate of at least 1021 / s, preferably with a maximum shear rate of 1071 / s, and especially preferably in a range of at least 2021 / s to a maximum of 1061 / s.

[0050] Preferably, the shear rate is determined from a ratio between the velocity difference of adjacent rotating or non-rotating components (e.g., rotor and stator) and their distance from each other.

[0051] Likewise, preferably within the scope of the present invention, it is preferred that the shearing occurs by means of at least one of the following: - rotor-rotor shearing device, that is, for example and preferably a homogenizing device with two rotating shearing elements arranged within a housing or container, which can be actuated in opposite directions or in the same direction, as indicated, for example, in a European patent with the Petition 870250081392, dated 10 / 09 / 2025, page 24 / 48 18 / 25 number EP 1125625 or EP 1825 907; - rotor-stator shear device, that is, for example, a homogenizing device with a rotating shear element disposed within a housing or container, which can be moved relative to a stationary stator, as indicated, for example, in European patent EP3031888B1 or EP3255130A1; - rotor-stator shear device, that is, for example and preferably, a homogenizing device with two rotating shear elements arranged within a housing or container, which can be actuated in opposite directions or in the same direction, and an additional stationary stator, as indicated, for example, in a European patent mentioned with the number EP 1125625 or EP 1825907; - high-pressure injection chamber, - static mixer, - extruder, especially screw extruder, - pump / pump assembly.

[0052] In a particularly preferred manner, the shearing occurs in a rotor-rotor-stator system, as described in document EP 1125625 or EP 1825907. In a preferred embodiment, the process according to the invention may be a process for producing a polyurea-thickened lubricating grease, consisting of or comprising the steps as described above and additionally comprising the steps: f) heating the intermediate product obtained in step e) to a temperature above 100°C under stirring; g) cooling the heated intermediate product from step f) to a temperature below 100°C, preferably below 80°C; h) obtaining a lubricating grease thickened with polyurea.

[0053] The polyurea-thickened lubricating grease obtained must be Petition 870250081392, dated 10 / 09 / 2025, page 25 / 48 19 / 25 preferably considered a terminal product for application in tribosystems.

[0054] Another aspect of the present invention is a process for producing at least one polyurea-thickened lubricating grease intermediate product, consisting of or comprising the following steps: a) provide at least one first thickening precursor; b) provide at least one second thickening precursor; c) to dose the thickening precursors provided from steps a) and b) in a mixing chamber, optionally adding at least one additional additive; d) mix said at least two thickening precursors as well as said optionally at least one other additive in the mixing and reaction chamber of the two thickening precursors; (e) to obtain an intermediate product of polyurea-thickened lubricating grease, in which, as the first thickening precursor, a pure amine or a mixture of a pure amine and / or alcohol is provided.

[0055] Pure amine and / or a thickener precursor is understood to be completely or substantially free of base oils and / or additives, as described herein.

[0056] Preferably, and as already described in step a), the first thickener precursor provided is selected from at least one amine, preferably selected from the group consisting of primary amines, preferably monoaminohydrocarbyl-, di- or polyaminohydrocarbylene compounds with 6 to 20 carbon atoms, or mixtures thereof, and / or, in step a), the first thickener precursor provided is selected from at least one alcohol, preferably selected from Petition 870250081392, dated 10 / 09 / 2025, page 26 / 48 20 / 25 group consisting of alcohols with hydrocarbyl or hydrocarbylene groups with 6 to 20 carbon atoms, or mixtures thereof, and the second precursor provided in step b) is selected from the group consisting of isocyanates, preferably mono- and / or poly-isocyanates with 5 to 20, especially preferably 6 to 15 carbon atoms, or mixtures thereof, wherein the first and / or second thickener precursor(s) is / are present as a pure substance or as a mixture with at least one base oil.

[0057] Preferably, the process according to the invention comprises, as described above, additionally the following steps: f) heating the intermediate product obtained in step e) to a temperature above 100°C under stirring; g) cooling the heated intermediate product from step f) to a temperature below 100°C, preferably below 80°C; h) obtaining lubricating grease thickened with polyurea.

[0058] A polyurea-thickened lubricating grease, obtained within the scope of the present invention, is, as already described, the process product of the in situ reaction of the amines and isocyanates described herein, preferably in the base oil, which is heated after the production of an intermediate product and then cooled again to obtain, as the final product, the polyurea-thickened lubricating grease.

[0059] The invention is described above with reference to a process. In another aspect, the invention relates to a device or the use of a device. The invention achieves the objective initially stated in relation to the device or use by making the device comprise a mixing chamber for mixing the thickening precursors and a stirring reactor. The mixing chamber Petition 870250081392, dated 10 / 09 / 2025, p. 27 / 48 21 / 25 preferably features a shear element and at least two dosing inlets for dosing the thickener precursors. Preferably, the mixing chamber is connected to the agitator reactor via a line. The agitator reactor has an agitator. In addition, the agitator reactor preferably has a cooling casing designed to cool the agitator reactor. According to one embodiment, the agitator reactor is connected to the mixing chamber via a connection.

[0060] The device and its use enjoy the same advantages and preferred embodiments as the process according to the invention and vice versa. In this sense, reference is made to the above embodiments, and their content is incorporated herein.

[0061] Another aspect of the present invention is the provision of a polyurea-thickened lubricating grease, preferably obtained or obtainable through a process according to one of the preceding embodiments, containing: a) 55 to 95% by weight, preferably 70 to 90% by weight of base oil b) 1 to 20% by weight, preferably 1.5 to 15% by weight of polyurea thickener; and optionally at least one other component c) 0.5% by weight to 40% by weight, preferably 2% to 10% by weight of additives; d) 0 to 20% by weight, preferably 0 to 5% by weight, of inorganic thickener, preferably silicon oxide; f) 0 to 20% by weight, preferably 0.1 to 15% by weight, of solid lubricants; (g) 0 to 20% by weight, especially 1 to 15% by weight, of other organic thickeners, preferably soap thickeners or complex soap thickeners based on calcium, lithium or aluminum soaps; Petition 870250081392, dated 10 / 09 / 2025, page 28 / 48 22 / 25 h) 1 to 15% by weight of lignin derivatives, wherein the polyurea-thickened lubricating grease is substantially free of biuret.

[0062] Biuret is formed as an undesirable byproduct, for example, as biuret oligomers when free and / or partially converted isocyanates react with amines. This is undesirable because it can lead to reduced thickening performance as well as increased thermal and oxidative aging of lubricating greases. Furthermore, biuret can dissociate during the process in such a way that a free amine group is present. As described above, in the case of temperature-conditioned urea group dissociation, regressively evolved free amines can lead to incompatibility with synthetic material and / or elastomer and incompatibility with skin. Free amines can also represent a significant odor nuisance.

[0063] “Substantially free of” in the context of the present invention means values ​​for certain substances that are present within a verification limit or in an amount of, at most, 2000 ppm, preferably 1000 ppm, especially preferably 500 ppm.

[0064] Preferably, the polyurea-thickened lubricating grease according to the invention has a cone penetration value of 200 to 400 mm / 10, preferably 265 to 385 mm / a0, determined in accordance with DIN ISO 2137.

[0065] By “penetration of a lubricating grease” is meant the depth of penetration - measured in 0.1 mm - of a standard cone under defined conditions.

[0066] It is preferable that a soap or complex soap thickener be present as component g) in the polyurea-thickened lubricating grease. If this is the case, the addition of the thickener of Petition 870250081392, dated 10 / 09 / 2025, page 29 / 48 23 / 25 Soap or complex soap grease preferably occurs after the production of the base grease during the cooling curve at the appropriate temperature (for example, by adding the soap or complex soap thickener, especially calcium soap or calcium complex soap, at a temperature of 140 to 115°C).

[0067] Preferably, for the production of base grease, heating is carried out at temperatures above 100°C or, especially preferably, above 130°C. Heating occurs after the reaction of thickener precursors to form the intermediate product of lubricating grease. The transformation into base grease takes place in a heated reactor, which can also be carried out as an autoclave or vacuum reactor.

[0068] Next, in a second stage, the formation of the thickener structure is completed through cooling, and eventually other components such as additives and / or base oil are added to adjust the desired consistency or property profile. The second stage can be carried out in a reactor from the first stage, but preferably the base grease is transferred from the reactor to a separate stirring boiler for cooling and mixing of any other components.

[0069] The invention is described in more detail below with the aid of a preferred embodiment with reference to the accompanying figure.

[0070] In this case, Figure 1 shows an example of an embodiment of an installation 2 for the process according to the invention, as well as its use according to the invention. The installation 2 has a mixing chamber 16 for mixing the thickener precursors, as well as an agitator reactor 11. The mixing chamber 16 has a shear element 17 and a dosing inlet 18 for dosing the thickener precursors. The figure shows, for example, Petition 870250081392, dated 10 / 09 / 2025, page 30 / 48 24 / 25 four separate dosing inlets AD, where for the process proposed here especially three inlets are sufficient. The mixing chamber 16 is connected to the agitator reactor 11 via a line 13. The agitator reactor 11 has an agitator 12 and a cooling casing 14. The agitator reactor 11 is connected to the mixing chamber 15 via a connection 15.

[0071] The mixing chamber 16 has the shear element 17, wherein the shear element 17 - as represented - may be configured as a rotary shear element 17 or as a rotor-stator-rotor shear device, high-pressure injection chamber, static mixer, extruder, especially screw extruder or as a pump / pump assembly.

[0072] With reference to Figure 1, the process according to the invention can be described as follows: the first thickener precursor and the second thickener precursor are dosed into the mixing chamber 16 via dosing inlets 18, for example, dosing inlets A and B. The thickener precursors are mixed in the mixing chamber 16 with reaction of the thickener precursors and sheared by means of the shearing element 17. Optionally, for example, via dosing inlet C, an additive can be dosed into the mixing chamber 16. At least one of the thickener precursors and / or the additive is then fed, according to the invention, at a temperature in a range of 0°C to less than 40°C. The mixture can be transferred to the agitator reactor 13 via line 13 and agitated there by means of the agitator 12. Furthermore, the fluid contained in the agitator reactor 11 can be cooled by means of the cooling casing 14.Through connection 15 the fluid can be transferred from the agitator reactor 11 to the mixing zone 16. To obtain polyurea-thickened lubricating grease from the urea-thickened lubricating grease intermediate product, the intermediate product is heated to... Petition 870250081392, dated 10 / 09 / 2025, p. 31 / 48 25 / 25 a temperature above 100°C in the agitator reactor 11, then cooled, and finally, the polyurea-thickened lubricating grease is obtained. Petition 870250081392, dated 10 / 09 / 2025, p. 32 / 48

Claims

1 / 6 CLAIMS 1.A process for producing an intermediate product of polyurea-thickened lubricating grease, characterized in that it consists of or comprises the following steps: a) providing at least one first thickener precursor; b) providing at least one second thickener precursor; c) dosing the thickener precursors from steps a) and b) into a mixing chamber, optionally with the additional addition of at least one additive; d) mixing said at least two precursors as well as said at least one other additive in the mixing chamber and reacting the two thickener precursors; e) obtaining at least one intermediate product of polyurea-thickened lubricating grease, wherein, to achieve cooling during the reaction in step d), at least one of the thickener precursors provided in steps a) and b) and / or said at least one additive from step c) has a temperature in a range of 0°C to less than 40°C, preferably in a range of 10°C to less than 40°C.

2. Process according to claim 1, characterized in that the first thickener precursor provided in step a) is selected from the group consisting of primary amines, preferably monoamino-hydrocarbyl-, di- or polyamino-hydrocarbylene compounds with 6 to 20 carbon atoms or alcohols with hydrocarbyl or hydrocarbylene groups with 6 to 20 carbon atoms, or mixtures thereof, wherein the first thickener precursor is present as a pure substance or as a mixture with at least one base oil.

3. Process according to claim 1 or 2, characterized in that the first thickener precursor provided in Petition 870250081392, dated 10 / 09 / 2025, page 33 / 48 2 / 6 step b) is selected from: isocyanates, preferably mono- and / or polyisocyanates with 5 to 20, especially preferably 6 to 15 carbon atoms, or mixtures thereof, wherein the thickener precursor being present as a pure substance or as a mixture of at least one base oil.

4. A process according to any of the preceding claims, characterized in that said at least one additive is selected from the group consisting of base oils, volatile hydrocarbons, cooled or liquefied gases, amines, alcohols, isocyanates, anti-oxidation agents, anti-wear protection agents, anti-corrosion agents, detergents, dyes, lubrication capacity enhancers, adhesion enhancers, viscosity additives, friction reducers, high-pressure additives and metal activators, simple soaps and / or complex soaps, preferably present as lithium, sodium, magnesium, calcium, aluminum or titanium soaps, water or mixtures thereof.

5. A process according to any one of the preceding claims, characterized in that cooling of the reaction in step d) is achieved further by the fact that components that evaporate or sublime are added as additives in step c).

6. Process according to any of the preceding claims, characterized in that the base oil has a kinematic viscosity of 12 to 2500 mm2 / s, preferably 30 to 500 mm2 / s at a temperature of 40°C.

7. Process according to any of the preceding claims, characterized in that the mixing in step d) occurs in the mixing chamber under shear.

8. Process according to claim 7, characterized in that the shearing occurs with a shear rate of at least 102 l / s, preferably with a maximum shear rate of 102 l / s, especially preferably in a range of at least 102 to at most 104 l / s.

9. Process according to claim 7 or 8, characterized in that the shearing occurs by means of at least one of the following: - rotor-rotor shearing device, - rotor-stator-rotor shearing device, - high-pressure injection chamber, - static mixer, - extruder, especially screw extruder, - pump / pump assembly.

10. Process for producing a polyurea-thickened lubricating grease, characterized in that it consists of or comprises the steps as defined in any of the preceding claims and additionally the steps: f) heating the intermediate product obtained in step e) to a temperature above 100°C under agitation; g) cooling the heated intermediate product from step f) to a temperature below 100°C, preferably below 80°C; h) obtaining a urea-thickened lubricating grease.

11. Process for producing a polyurea-thickened intermediate product, characterized in that it consists of or comprises the following steps: a) providing at least one first thickener precursor; b) providing at least one second thickener precursor; c) dosing the thickener precursors provided from steps a) and b) into a mixing chamber, optionally with the additional addition of at least one additive; d) mixing said at least two thickener precursors as well as said at least one other additive in the mixing chamber and reaction of the two thickener precursors; e) obtaining a urea-thickened lubricating grease intermediate product, in which, as the first thickener precursor, pure amine or a mixture of pure amines and / or alcohol is provided.

12. Process according to claim 11, characterized in that, in step (a), as the first thickening precursor provided, at least one amine is selected, preferably selected from the group consisting of primary amines, preferably monoaminohydrocarbyl, di- or polyaminohydrocarbylene compounds with 6 to 20 carbon atoms, or mixtures thereof, and / or in that, in step (a), as the first thickening precursor provided, at least one alcohol is selected, preferably selected from the group consisting of alcohols with 6 to 20 carbon atoms, or mixtures thereof, and in that the second thickening precursor provided in step (b) is selected from the group consisting of isocyanates, preferably mono- and / or polyisocyanates with 5 to 20, especially preferably 6 to 15 carbon atoms, or mixtures thereof,where the first and / or second thickening precursor is present as a pure substance or as a mixture of at least one base oil.

13. Process for producing a polyurea-thickened lubricating grease, characterized in that it consists of or comprises the steps as defined in any one of claims 11 or 12 and additionally the steps: f) heating the intermediate product obtained in step e) to a temperature above 100°C under agitation; g) cooling the heated intermediate product from step f) to a temperature below 100°C, preferably below 80°C; h) obtaining a polyurea-thickened lubricating grease.

14. Use of a device, characterized in that it comprises: - a mixing chamber (16) for mixing the thickening precursors, - an agitator reactor (11), wherein the mixing chamber (16) has a shear element (17) and at least two metering inlets (18) for metering the thickening precursors and is connected to the agitator reactor via a line (13), especially wherein the agitator reactor (11) has an agitator (12) and a cooling casing (14) and, optionally, is connected to the mixing zone (16) via a connection (15), for producing a polyurea-thickened lubricating grease (10) or a polyurea-thickened lubricating grease intermediate product with a process as defined in any of the preceding claims.

15. Polyurea-thickened lubricating grease, preferably obtained or obtainable by a process as defined in any of the preceding claims, characterized in that it contains: a) 55 to 95% by weight, preferably 70 to 90% by weight of base oil; b) 1 to 20% by weight, preferably 1.5 to 15% by weight of polyurea thickener; and optionally at least one other component; c) 0.5% by weight to 40% by weight, preferably 2 to 10% by weight of additives; Petition 870250081392, dated 10 / 09 / 2025, p.37 / 48 6 / 6 d) 0 to 20% by weight, preferably 0 to 5% by weight, of inorganic thickeners, preferably silicon dioxide; f) 0 to 20% by weight, preferably 0.1 to 15% by weight, of solid lubricants; g) 0 to 20% by weight, in particular 1 to 15% by weight, of other organic thickeners, preferably soap thickeners or complex soaps based on calcium, lithium or aluminum soaps; h) 1 to 15% by weight of lignin derivatives, the polyurea-thickened lubricating grease being essentially biuret-free.

16. Polyurea-thickened lubricating grease according to claim 15, characterized in that the polyurea-thickened lubricating grease has a cone penetration value of 200 to 400 mm / 10, preferably in the range of 265 to 385 mm / 10, determined in accordance with DIN ISO 2137. Petition 870250081392, dated 10 / 09 / 2025, pp. 38 / 48

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