Graphene superparticles, method for production thereof and use thereof

Abstract

The invention relates to a method for producing graphene superparticles by dispersing a graphene material having a particle diameter d50 of 0.5 m to 100 m in a solvent, preferably adding an additive to the dispersion, and at least partially removing the solvent from the dispersion thus obtained by spray drying to obtain graphene superparticles.

Description

Technical Field

[0001] This invention relates to a method for producing graphene superparticles, to the graphene superparticles themselves, and to their uses. Background Technology

[0002] There are various discussions in the technical literature regarding graphene and its production, properties and uses, such as Römpp Online (RÖMPP Editorial Team, Balgar T, Graphene, RD-07-02758 (2010), Böckler F., Dill B., Eisenbrand G., Faupel F., Fugmann B., Gamse T., Matissek R., Pohnert G., Rühling A., Schmidt S., Sprenger G., RÖMPP [Online], Stuttgart, Georg Thieme Publishers, [September 2022] https: / / roempp.thieme.de / lexicon / RD-07-02758).

[0003] Just as in graphite, each carbon atom in graphene is covalently linked to three adjacent atoms via σ bonds. The C-C bond length is 142 pm. These atoms are sp... 2 Hybridized, and the σ bonds lie in a single plane. Graphite therefore has a planar structure. Partially filled p z The orbitals are preserved on each atom. These p z The orbitals are orthogonal to the bond plane and form a delocalized π-electron system, which is the most important factor in determining the electronic properties of graphene.

[0004] In crystallographic terminology, graphene can be described by having unit cell vectors. = = 0.246 nm is described by two equivalent sublattices, with an angle of 60° between them. The unit cell is composed of the corresponding positions (0, 0) and ( a / 3, 2 b It consists of two carbon atoms at position / 3). Therefore, the atomic density is 38.2 nm. -2 .

[0005] The methods described below can be used with all graphenes specified below. The above definitions apply to these graphenes.

[0006] In this invention, "graphene material" refers to one or more materials according to ISO / TS 80004-13, namely graphene, graphene-type carbon materials, single-layer, double-layer and triple-layer graphene, epitaxial graphene, exfoliated graphene, few-layer graphene, multilayer graphene, few-layer nanoribbons, graphene nanoplates, graphene nanoplatelets, graphene nanosheets, graphene microsheets, graphene nanoflakes, graphene nanoribbons, graphene oxide, graphene oxide nanosheets, multilayer graphene oxide, graphene quantum dots, graphite, graphite nanoplates, graphite nanosheets, graphite nanoflakes, graphite oxide, reduced graphene oxide, or mixtures of these materials.

[0007] In this invention, fillers are understood to refer to boron nitride, nitrides in general, carbon-based materials (diamine), aluminum-based materials, metal particles and alloys, TiO2, ZnO, MgO, noble metals and their alloys and metal salts, silicon dioxide and silicates, SiC materials, layered materials (WS2, vanadium-based, silicon-based), composite components such as fibers, retarders, impact modifiers, pigments and UV stabilizers.

[0008] Graphene materials are used in many technological fields. This is illustrated, for example, in application EP 21150690. Materials composed of graphene, such as so-called composite materials, are also part of the prior art.

[0009] WO 2016078664 A1 discloses a composite material in which appropriately selected graphene is used and a binder material is used to provide a structure-giving substance for a given macroscopic surface.

[0010] The polynorbornene / graphene oxide composite material described in KR 1190014 B1 is used to modulate the gas barrier properties and various mechanical parameters in the layer structure.

[0011] KR 20190048574 provides an example of producing a composite material containing graphene oxide using a dispersion of 10 g / L in distilled water. Thus, only a 1% by weight of graphene material is achieved. The graphene oxide particles are partially aggregated into particles with an approximately spherical shape and a diameter of less than 30 µm. Another portion exists in sheet form with different topologies. A free-flowing composite material was not obtained here.

[0012] In the paper by S. Wintzheimer et al., "Supraparticles: Functionality from Uniform Structural Motifs", ACS NANO, 12 (2018), 5093-5120, nanoparticles form the building blocks of superparticles. Using the controlled agglomeration of entirely single nanoparticles, superparticles possessing certain electronic, plasmonic, magnetic, and / or photonic properties are obtained. To induce such agglomeration, the van der Waals or electrostatic forces present between the nanoparticles are utilized by spray drying, or alternatively, the nanoparticles are combined in an environment where nanoparticles are formed using a sol-gel process, or sonochemical methods are employed. Especially in the case of spray drying, the geometry of the apparatus used for this purpose or any relation to the properties of the resulting agglomerated products is not discussed.

[0013] Graphene materials are available as powders and often have very low bulk densities, for example, in the range of 2 to 400 g / L. In addition to their low bulk density, most graphene materials also exhibit poor flowability and / or generate significant amounts of dust during transfer via gravity-driven flow. This leads to undesirable handling properties and problems in weighing and metering processes, and is certainly considered critical in relation to aspects involving environmental protection and operator safety.

[0014] For example, when this powder is incorporated into an elastomer system, as is the case in rubber kneading, poor handling properties are evident. The production of well-filled rubber compounds depends on incorporating powdered fillers at the right time and for the right duration. These are poured into a mixing chamber using a hopper and then pushed along rotating rollers by a pneumatic piston. The shear forces at play in this mixing process break down filler agglomerates and thus facilitate their distribution. Therefore, the maximum achievable filler level depends essentially on the shear forces acting upon it. This is challenging in the case of particularly soft polymer mixtures, where it is impossible to establish any large shear forces for material-related reasons.

[0015] For example, it is known to form fine graphite or graphene agglomerates in electrode production. However, due to the size of the agglomerate particles, the free flowability of this conventional material is insufficient to enable its use in conventional compounding or extrusion machines.

[0016] It is also known that spray drying can be used to optimize powder systems, as spray drying of graphene dispersions, for example, results in spherical agglomerates. However, to date, no powders composed of graphene materials with improved flowability have been discovered.

[0017] To characterize the flowability of materials, various testing methods are employed in this invention, including the following measurements or determinations.

[0018] - According to the angle of repose in ISO 4324,

[0019] - Dynamic avalanche angle, and

[0020] - According to the Hausner factor of ASTM 527.

[0021] In the context of this invention, another measurement is the dust value according to DIN 55992.

[0022] The parameters described above are well known to those skilled in the art and have been determined using the test methods outlined below. The angle of repose and the angle of avalanche are expressed in degrees (°).

[0023] The better at least two, or even three, of these values ​​for the material, the better. This means...

[0024] - Low angle of repose

[0025] - Low dynamic avalanche angle,

[0026] - Low Hausner factor

[0027] The better the flowability of the material, the less dust is generated during the processing of the material used in this invention, i.e., the material proposed and claimed herein.

[0028] The terms "dust value" and "dust evolution" are synonymous in the context of this invention. Conventionally produced graphene powders are cohesive, which is synonymous with high measured values, and therefore only exhibit low flowability and high dust evolution. Such powders are difficult to process or can only be processed under cumbersome technical safety measures, and only achieve low bulk density when the dust value is high.

[0029] Therefore, there is a need for a technical solution that provides powdered graphene materials with improved flowability.

[0030] There is also a continuous need to reduce the amount of dust generated. This is because, firstly, dust causes pollution and makes it difficult to measure the amount of filler actually introduced into the matrix system. Secondly, for reasons related to occupational health and environmental protection, dust must be removed by suction or other means.

[0031] Furthermore, the dust and typically low bulk density of graphene materials increase the cost of introducing them into desired matrix systems. For example, problems arise when producing thermoplastic compounded materials filled with graphene in an extruder. For these reasons, it is difficult or impossible to ensure compliance with the necessary time sequence requirements for introducing powdered graphene materials during the production process of thermoplastic systems.

[0032] Furthermore, the electrical conductivity of graphene, as is known to those skilled in the art, limits its use in electrically insulating composites. Therefore, additional electrically insulating materials are needed. However, the use of such materials has the drawback of further limiting the thermal conductivity of graphene. Therefore, it is necessary to effectively connect graphene materials to insulators to achieve complete electrical insulation at high thermal conductivity. Summary of the Invention

[0033] Therefore, one object of the present invention is to improve a spray drying method for producing powders containing free-flowing graphene material, wherein the graphene material or its formulations or masterbatches have improved flowability and / or produce less dust during processing. The resulting graphene material is also thermally conductive and simultaneously electrically insulating.

[0034] This objective is achieved by providing a method for producing graphene supraparticles, the method comprising the following steps:

[0035] (a) Using at least one particle size diameter d from 0.5 µm to 100 µm 50 The graphene material is mixed into a solvent, and

[0036] (b) Add to the dispersion obtained in step (a) and any step (a1)

[0037] Based on the mass of the graphene material used, 0-100% by weight, preferably 0.1-100% by weight, of dispersants, emulsifiers, wetting agents, and / or defoamers.

[0038] and subsequently

[0039] (c) Remove at least part of the solvent from the dispersion obtained in step (b) by spray drying.

[0040] And thus obtained graphene superparticles.

[0041] Preferably, at least one other material (a1) is used simultaneously or successively, which is selected from graphene materials, or SiO2, alumina, TiO2, MgO, ZnO, SbO, organic fillers, or polymers, or phosphates (esters), chlorides, sulfates (esters), nitrites (esters).

[0042] And the particle diameter d of said at least one additional material 50 It is at least 10 times smaller than graphene material (a).

[0043] More preferably, (a1) the material is selected from graphene, alumina, TiO2, MgO, ZnO, SbO, organic fillers, or selected from phosphates (esters), chlorides, sulfates (esters), and nitrites (esters), wherein the particle diameter d of at least one of the additional materials is... 50 It is at least 10 times smaller than graphene material (a).

[0044] Surprisingly, it has been discovered that graphene dispersions containing additives can be spray-dried.

[0045] It has been found that a dispersion of the following graphene materials can be spray-dried, wherein additional materials selected from: other graphene materials, SiO2, alumina, TiO2, MgO, ZnO, SbO, organic fillers, polymers, or phosphates (esters), chlorides, sulfates (esters), nitrites (esters) can be optionally added to the dispersion.

[0046] Optionally contains dispersants or emulsifiers, or wetting agents and / or defoamers.

[0047] Simultaneously achieving improved flowability of spray-dried materials, as well as the desired thermal conductivity and electrical insulation properties.

[0048] During the drying process in an aqueous or alkanoic solution containing additives, the surface of the graphene material particles is wetted and stabilized with the additives, or has already been wetted and stabilized with additives. Spray drying provides graphene superparticles of graphene material through agglomeration.

[0049] The agglomerated graphene particles obtained after step (c) are superparticles of graphene particles. These are referred to as "graphene superparticles" or "superparticles" in this invention. These graphene superparticles preferably have a spherical or near-spherical shape and a particle diameter d of 1 µm to 500 µm, preferably 5 µm to 250 µm, more preferably 50 µm to 100 µm. 50 .

[0050] In this invention, particle diameter was measured using a Partica LA-950V2 laser scattering particle size analyzer from Rentsch Technology. All particles were analyzed in water. The pump circulation rate was set to 6, and the stirrer speed was set to 6. For analysis of the starting material, sonication was performed at level 6 for 1 minute. The graphene superparticles were measured in a 0.001 wt% soap solution to stabilize them.

[0051] The advantage of the method according to the invention is that the resulting graphene superparticles exhibit improved fluidity compared to conventional graphene particles. It has now been found that graphene superparticles only exhibit improved fluidity when the particle diameter d exceeds at least 40 µm. 50 It only exhibits good flowability at this stage. It has a particle diameter d of at least 50 µm, preferably at least 70 µm. 50 The graphene superparticles have particularly good fluidity.

[0052] The graphene superparticles of the present invention have a graphene content of at least 50% by weight.

[0053] In step (a), the amounts of graphene material and the other material (a1) are 50:50, preferably 60:40, and more preferably 80:20.

[0054] Graphene superparticles have a surface area of ​​400m as measured by Brunauer-Emmett-Teller (BET) surface area analysis. 2 / g BET or less, preferably 300 m 2 Surface area below / g BET.

[0055] In this context, the additives used, such as dispersants, emulsifiers, wetting agents, and / or defoamers, facilitate the operation of the dispersion without affecting the inherent properties of the graphene material.

[0056] In addition to improved flowability, the packing density of the resulting graphene superparticles is also increased. Furthermore, the material obtained by this method can be easily metered and added to any conventional matrix material. During the processing of the graphene superparticles obtained according to the present invention, the dust level is exceptionally low, thus improving operational safety. Moreover, the availability of the material for further processing is maintained. For example, in a conventional compounding machine, the graphene superparticles can be disintegrated into graphene material, retaining its original physical properties, using active shear force in a matrix material, preferably a polymer, monomer, or solvent.

[0057] This invention also provides graphene superparticles, characterized by having

[0058] - An angle of repose from 50° to 20°, preferably 40° to 25°, more preferably 37.5° to 30°, and especially preferably 37° to 27.5° according to ISO 4324.

[0059] - A dynamic avalanche angle of 65° to 30°, preferably 55° to 35°, and most preferably 45° to 40°, and / or

[0060] - 1.5 to 1, preferably 1.4 to 1.1, more preferably 1.3 to 1.2 of the Hausner factor according to ASTM 527, or

[0061] - A dust value of 10 to 0.001, preferably 5 to 0.01, more preferably 3 to 0.1 according to DIN 55992 Type I.

[0062] The graphene superparticles according to the present invention or obtained according to the present invention provide free-flowing yet still dust-free powder.

[0063] The graphene superparticles according to the invention preferably possess the claimed features. Therefore, these graphene superparticles have an angle of repose of 50° to 20° according to ISO 4324 and a dynamic avalanche angle of 65° to 30°, a Hausner factor of 1.5 to 1 according to ASTM 527, and a dust value of 10 to 0.001 according to DIN 55992 Type I. These graphene superparticles preferably have a diameter d of 1 µm to 500 µm. 50 .

[0064] For grading, the graphene superparticles according to the present invention or obtained according to the present invention can be collected in three different containers and thus divided into three sizes.

[0065] Following step (c) of the method according to the invention, the so-called "coarse material" can be vertically collected in a collection container downstream of the drying chamber. Powder comprising graphene superparticles composed of graphene particles according to the invention or obtained according to the invention undergoes a correspondingly low level of shear force during the process, meaning that very little fragmentation is obtained.

[0066] Downstream of the drying chamber, the powder can be introduced into a cyclone separator. Here, the so-called "fine fraction" is separated from the so-called "cyclone separator product." The cyclone separator product undergoes high shear forces due to centrifugal force, resulting in the graphene superparticles being particularly easy to disperse. The fine fraction can be collected in a filter pad downstream of the cyclone separator.

[0067] The present invention also provides the use of graphene superparticles according to the invention or obtained according to the invention in the following applications:

[0068] - Thermally conductive materials and adhesives, such as thin films, underflow materials, castable electronic materials, phase-change materials, thermal pastes, and encapsulation formulations, especially in the fields of batteries, sensors, ICs, and LEDs.

[0069] - Composite materials based on thermoplastics, thermosetting materials, and / or elastomers, which have increased electrical and / or thermal conductivity or are used for EMI shielding, particularly in the enclosures of electrical components, motors, battery packs, and pipes.

[0070] - Coatings and varnishes with thermal and / or electrical conductivity, or for applications in EMI shielding.

[0071] - Thermally and / or electrically conductive oil, coolant, or ink.

[0072] In particular, the graphene superparticles according to the present invention or obtained according to the present invention are suitable for use in thermoplastics selected from standard thermoplastics, preferably PE, PP, PS, PVC, α-olefins, butadiene derivatives and / or Vestenamer. ® ,

[0073] Industrial thermoplastics, preferably PET, PMMA, PC, POM, PA, PBT, PEBA, TPU, PU and / or TPE.

[0074] High-performance thermoplastics, preferably PPS, PEEK, PES, PI and / or PEI.

[0075] Copolymers, elastomers, preferably silicones, more preferably room temperature crosslinking (RTV) silicones, high temperature crosslinking (HTV) silicones, liquid silicone rubbers (LSR), heat-crosslinking rubbers (HCR), acrylates, and / or pastes containing polysiloxanes and oligosiloxanes.

[0076] Polyurethane, rubber, preferably styrene-butadiene rubber (SBR), butadiene rubber (BR) and / or natural rubber, thermosetting materials, preferably polyurethane, polyester resin, phenolic resin, epoxy resin, acrylate resin and / or silicone resin,

[0077] Solvents, preferably aprotic-nonpolar, aprotic-polar, and / or protic solvents.

[0078] Oil, preferably mineral oil, silicone oil and / or processing oil.

[0079] More preferably, the graphene superparticles according to the present invention or obtained according to the present invention can be used as additives in the plastics processing industry. They are preferably used in the compounding, extrusion or injection molding of plastics.

[0080] The advantage of the claimed uses is that, in some cases, it is practically possible to compound graphene. Furthermore, the uses of this invention allow for simple and reliable processing of graphene, as well as so-called "rapid injection molding" (RIM).

[0081] This application enables the efficient use of high-performance fillers, such as graphene, without compromising the high-performance properties of the matrix, as is the case with PA12.

[0082] When used as an additive, graphene superparticles enable improvements in thermal, electrical, and / or mechanical properties, such as improvements in the degree of extrusion of high-performance polymers for high-performance applications where filler content must be kept low to preserve the properties of the matrix.

[0083] The use of graphene superparticles according to the present invention also achieves a favorable lubrication effect, simplifying compounding and extrusion, which would otherwise be difficult when using fillers. Furthermore, electrical conductivity is improved.

[0084] Further advantages will emerge in the processing of masterbatches for thermoplastics, epoxy resins, and elastomers, and / or very often in the processing of concentrates known as masterbatches.

[0085] When used in gas membrane or gas conduction systems, the tendency to leak is also reduced.

[0086] The invention is described in more detail below.

[0087] The method according to the invention is schematically shown Figure 2 middle.

[0088] In step (a) of the method according to the invention, particles with a diameter d of 0.5 µm to 100 µm are... 50 The graphene material is mixed into the solvent. Optionally, other materials may be added (step (a1)). These materials may be, for example, other graphene materials, but are also selected from: SiO2, alumina, TiO2, MgO, ZnO, SbO, organic fillers, polymers, or phosphates (esters), chlorides, sulfates (esters), and nitrites (esters).

[0089] The particle dispersion obtained after step (b) preferably has a particle diameter d of 0.5 µm to 100 µm, more preferably 0.5 µm to 60 µm, and more preferably 2 µm to 40 µm. 50 .

[0090] The particle diameter d of the graphene material in step (a) 50 It is equal to the graphene material obtained in step (b).

[0091] The graphene particles in step (a) are at least an order of magnitude larger than the other graphene particles, alumina particles, SiO2 particles, TiO2 particles, MgO particles, ZnO particles, SbO particles, polymer particles, organic fillers, or phosphate (ester), chloride, sulfate (ester), and nitrite (ester) particles used in step (a1).

[0092] The diameter d of the additional graphene material, alumina particles, SiO2 particles, TiO2 particles, MgO particles, ZnO particles, SbO particles, polymer particles, organic fillers, or phosphates (esters), chlorides, sulfates (esters), and nitrites (esters) used in step (a1) of the method according to the invention 50 Smaller than the diameter d of the initial graphene particles 50 The diameter d of the material used in step (a1) of the method according to the invention 50 Further preferred is the diameter d of the graphene particles used in step (a). 50 The size is at least 10 times smaller, more preferably at least 20 times smaller, and most preferably at least 50 times smaller. The material used in step (a1) can advantageously have a diameter d of 500 nm or less. 50 .

[0093] According to a preferred embodiment of the invention, the material used in step (a1) is a hydrophobic material. The other graphene materials, alumina particles, SiO2 particles, TiO2 particles, MgO particles, ZnO particles, SbO particles, polymer particles, organic fillers, or phosphates (esters), chlorides, sulfates (esters), and nitrites (esters) used according to the invention are therefore preferably, unlike hydrophilic materials, do not have (surface) modifications that improve their water solubility.

[0094] Due to the improved material properties, the graphene superparticles obtained in step (c) can advantageously be disintegrated into graphene material in a mixing machine, in a matrix material, preferably a polymer, monomer, or solvent, using active shear force, while maintaining the original physical properties.

[0095] In step (a1), the organic filler used may be a polymer selected from the following: PE, PP, PS, PVC, α-olefins, butadiene derivatives, Vestenamer. ® (Rubber additives from Evonik, Essen, Germany), industrial thermoplastics, preferably PET, PMMA, PC, POM, PA, PBT, PEBA, TPU, PU, ​​TPE, high-performance thermoplastics, preferably PPS, PEEK, PES, PI, PEI.

[0096] In this invention, the inorganic filler is also considered to include salts that are insoluble in the solvent used in step (a).

[0097] It may be further advantageous to select the solvent in step (a) from water, distilled water, and alkanols (preferably ethanol).

[0098] Solvents can be selected from hexane, chlorobenzene, toluene, tetrachloromethane, dichloromethane, water, distilled water, ethanol, or mixtures of these solvents.

[0099] These and other solvents suitable for graphene materials and additives are known to those skilled in the art.

[0100] In the method according to the invention, it may be advantageous to produce the dispersion intermittently or continuously. In step (a), and if appropriate, in the case of intermittent preparation in step (a1), the graphene material or the material used in step (a1) can be weighed and gradually added to the solvent. A suitable stirring unit, such as an ultrasonic finger or Ultraturrax, can be used here. It has been observed that the viscosity of the dispersion increases with increasing mass proportion of the graphene material or the other material in step (a1).

[0101] More preferably, a uniform dispersion is obtained in step (a) and, if appropriate, step (a1). The properties of the dispersion are crucial to the progress of step (c) of the method. This is because the size of the graphene superparticles is influenced by the viscosity, surface tension, density, and mass ratio of the graphene material, as well as the geometry of the drying chamber.

[0102] As described above, in step (c) of the method according to the invention, the dispersion obtained in step (b) is subjected to spray drying. The drying method in step (c) preferably includes the following steps:

[0103] The dispersion obtained in step (b) is sprayed into an inert gas stream using a spray unit, wherein the solvent in the droplets formed by the spray evaporates at least partially.

[0104] In spray drying, a dispersion consisting of graphene material and any one or more additives is atomized by applying shear force. During this process, initial film formation and subsequent film separation into numerous droplets occur. These droplets surround a hot gas stream, preferably an inert gas, more preferably nitrogen, and the temperature is preferably in the range of 80 to 400°C. The temperature can be adjusted according to the solvent.

[0105] In the context of this invention, graphene particles according to the invention or obtained according to the invention are referred to as “superparticles” or “graphene superparticles” when they are in agglomerated form.

[0106] In step (c), the solvent in the droplet evaporates and is received by the gas stream. This cools the gas. The evaporation of the solvent causes a continuous decrease in the droplet volume. Therefore, as the droplet passes through the gas stream, the mass ratio of graphene material and any one or more additives in the droplet increases. The drying of the droplet and the thus decreasing volume are initially linear until a so-called “lock point” is reached. At the lock point, a hard shell forms, and the core of the formed graphene superparticle is wet, meaning that solvent residues, in addition to the additives, are also present in the core of the graphene superparticle. Further drying is slower because moisture must travel from the core to the surface. The drying rate can be adjusted by the temperature of the inert gas stream during step (c) of the method.

[0107] If this is very high, hollow graphene superparticles can be obtained.

[0108] If the drying rate is low, the result is usually solid graphene superparticles.

[0109] In this second case, attention must be paid to the required residence time in the drying chamber, otherwise the drying will be incomplete.

[0110] Furthermore, the particle diameter of graphene superparticles can be adjusted by the drying rate. Other means of influencing the size of graphene superparticles include the selection of the spray unit (preferably a two-phase nozzle) and the selection of the mass flow ratio of gas to the spray dispersion (called the gas-liquid ratio).

[0111] Not bound by any particular theory, but various routes 1-4 can exist for forming graphene superparticles during the process of carrying out the method according to the invention, as illustrated in the diagram. Figure 3 The route depends on factors including the temperature of the inert gas stream. Depending on the route followed after step (c), the graphene superparticles have their own distinct shapes. F、 J, P They have pairs of different properties.

[0112] The dispersion can be atomized, for example, via a two-phase nozzle. In this case, the required shear energy is applied by a gas stream that is greatly accelerated in the contraction section. Depending on the gas volumetric flow rate and therefore the gas velocity at the nozzle exit, either high or low shear force is applied. This alters the droplet size and droplet size distribution of the dispersion.

[0113] The mass percentage of graphene material can be from 5% to 50% by weight, based on the solvent. The mass percentage of additives used, expressed as a percentage by weight, is based on the mass of the graphene material used.

[0114] The additive can be dispersed using a suitable stirring unit. To prevent the mixture from separating, it is preferable to continuously stir the dispersion.

[0115] In the case of continuous preparation in step (a) and, if appropriate, step (a1), graphene material or other material from step (a1) can be added to the mixture of solvent and additives via a suitable machine, preferably by a conveying screw. If two phases are obtained, these can be pumped through a dispersion chamber. A suitable stirring unit is required to provide the necessary energy input. The selection of the dispersion chamber and the energy input to be established are known to those skilled in the art. The dispersion is then continuously fed into the stirring unit.

[0116] In step (b) of the method according to the invention, the additive (if any) may be selected from dispersants, emulsifiers or wetting agents and / or defoamers.

[0117] Based on the mass of the graphene material used, the at least one additive in step (b) may be used in a mass ratio of 0% to 100% by weight, preferably 0.1% to 100% by weight, more preferably 0.1% to 10% by weight of the respective additive.

[0118] The at least one wetting or dispersing agent is preferably selected from copolymers based on oxyalkylene glycol alkenyl ethers or polyepoxyalkylene alkenyl ethers and unsaturated dicarboxylic acid derivatives. Such copolymers are disclosed in patent specification EP 114292 B1 and ensure, for example, the production of binder-free, co-solvent-free, or VOC-free pigment concentrates based on transparent iron oxides.

[0119] In step (c) of the method according to the invention, the spray unit may be a device having at least one two-phase nozzle and / or the inert gas used may be nitrogen, preferably dry nitrogen, the temperature of the inert gas stream may be further preferably set in the range of 200°C to 400°C above the cooling limit temperature of the solvent, further preferably in the range of 220°C to 300°C, and / or the spray droplets may have a size of 30 to 1000 µm.

[0120] The size of the spray droplets is caused by the atomizer force, which is known to those skilled in the art and can be adjusted by the nitrogen flow rate or by the atomizer gas flow rate through a shear effect. Detailed Implementation

[0121] The invention is illustrated in detail by way of examples, but is not limited to the subject matter of the invention.

[0122] Using the JEOL NeoScope, the SEM images shown below were evaluated by spreading the powdered material to be examined onto an adhesive graphene film and carefully removing excess material using a set of bellows. The SEM images shown in this invention were recorded at 10 kV.

[0123] According to the Hausner factor of ASTM 527

[0124] The Hausner factor is determined according to ASTM 527. It is also a measure of powder compactability.

[0125] In the determination of the Hausner factor, the ratio between bulk density and compacted density is formed. This is done by introducing 100 g of powder material into a graduated cylinder. Depending on the bulk density, a 100 ml or 250 ml graduated cylinder can be used. The powder is introduced gradually and carefully. The volume of the loose bed is read, and this is the bulk volume. The quotient of the introduced powder mass and the bulk volume is the bulk density.

[0126] The powder is then compacted until no volume change is visible. The resulting volume is the compacted volume, which is then recorded.

[0127] The quotient of the introduced powder mass and the compacted volume is the compacted density.

[0128] The Hausner factor, calculated from bulk density and compaction density, can be classified into various evaluation levels, as shown in Table 1.

[0129] Table 1. Classification of Hausner Factor

[0130]

[0131] Dynamic avalanche angle, measured using a rotary powder analyzer.

[0132] The dynamic avalanche angle is also a measure of powder flowability and can be measured directly.

[0133] In this invention, a rotary powder analyzer from PS Prozesstechnik GmbH is used. Revolution Powder Analyzer (Model number Rev2015). For example... Figure 4a As shown, this involves loading a predetermined amount into a rotating drum and using a camera to determine the angle at which the material begins to form an avalanche. During the avalanche, the material forms on both the surface and the horizontal plane (where particles are formed). h The smaller avalanche angle between ) ava,h ) indicates better material flowability. The avalanche angle is mathematically positive upwards at ( ava ) and horizontal plane ( hMeasurements are taken between [variables]. The operating modes of the powder analyzer are known to those skilled in the art, as are the variables measured by it. Details can be found, for example, in the following article by Amado: "Advances in SLS powder characterization", 22nd Annual International Solid Freeform Fabrication Symposium - An Additive Manufacturing Conference, SFF, 2011, pp. 438-452.

[0134] 100 ml of powder material was weighed out and introduced into a glass chamber. The chamber rotated at 0.5 rpm, forming an angle. Upon reaching the maximum value of this angle (dynamic avalanche angle), the powder began to flow down the slope. A camera recorded the powder movement, thus continuously determining the dynamic avalanche angle. Furthermore, the avalanche energy of the downward-flowing powder was calculated.

[0135] The dynamic avalanche angle can vary from 70° for powders with very poor flow to 30° for powders with very efficient flow.

[0136] The measurement parameters for the flowability procedure correspond to the standard settings for dark powders:

[0137] 0.5 rpm

[0138] ·150 Avalanche Starting Point

[0139] • Avalanche threshold: 0.65%

[0140] • Camera: Shutter speed 6 ms, gain 6 dB (black powder), 10 frames per second

[0141] Uniformity and flow properties can be directly calculated using the standard deviation of dynamic avalanche angle and avalanche energy.

[0142] According to ISO 4324, the slope angle

[0143] The measurement of the slope angle provides further insight into the powder's flowability.

[0144] In this invention, 100 ml of powder material is introduced into a funnel with a 10 mm outlet. The outlet is closed. The funnel is fixed 7.5 cm away from a plate with a diameter of 10 cm and a height of 25 cm. The funnel outlet is opened, and the powder flows onto the plate. The powder thus forms a cone with a corresponding bevel angle.

[0145] The slope angle can be graded into various evaluation levels, as shown in Table 2.

[0146] Table 2. Slope Angle and Flow Assessment

[0147]

[0148] Scanning electron microscope (SEM)

[0149] For the SEM images disclosed herein, a FlexSEM 1000 II VP-SEM was used. To do this, the powder to be examined was dispersed onto a viscous graphene film. Excess material was carefully removed using a set of bellows. Images were recorded at 10 kV.

[0150] Electrical insulation

[0151] Electrical insulation was measured using an FE50 toroidal electrode and a Mili-TO 3-ohmmeter (Fischer Elektronik) according to ISO 62631.

[0152] thermal conductivity

[0153] According to ASTM E1530-19, thermal conductivity was determined in equilibrium using a two-dimensional sample approximately 10 mm thick in contact with a 120 silicone-type thermal joint compound (Wakefield-Vette) using a protected hot plate (Thermtest GHFM-02). The upper plate was set to 35°C, and the lower plate to 15°C. Measurements were taken after a 60-minute equilibration period.

[0154] The apparatus used in the embodiments:

[0155] Somakon MP-GL laboratory mixer, Büchi B290 spray dryer, UltraTurrax IKA T50. The spray dryers used are shown in schematic diagram. Figure 4b middle.

[0156] Example 1. Gamor GO

[0157] The graphene material used is Gamor GO (from Gamor Inc., Orlando, Florida (USA)).

[0158] Figure 5 This displays a SEM image of the graphene material. It is in the form of particles, some of which are in the form of agglomerates.

[0159] Figure 6 Displays the corresponding particle size distribution.

[0160] The following characteristic diameter is measured here: d 10 0.94 µm, d 50 2.42 µm, d 90 5.53 µm.

[0161] Production of dispersions:

[0162] The following describes the production of a dispersion consisting of ethanol and Gamor GO.

[0163] Gamor GO was stirred into ethanol until a 20% by weight ratio was achieved. The dispersion was then dispersed using an H7 ultrasonic fingertip. The device was set to 100% amplitude and 0.75 cycles. Dispersion was initially allowed to proceed for 5 minutes. The container was then closed and the device was shaken vigorously for 30 seconds. This procedure was repeated a total of 3 times.

[0164] Once a homogeneous dispersion is obtained, it is stirred to prevent segregation. This is done using a stirring plate and a soccer ball-shaped stirring rod at 600 rpm.

[0165] Even during step (c), the dispersion is stirred to prevent separation. The process parameters for step (c) are:

[0166] Inlet temperature: 100℃, outlet temperature: 70℃, nozzle gas flow rate: 366 l / min

[0167] Inspirator power 50% (approximately 20 m³ / h), pump power 50% (approximately 8 ml / min).

[0168] The gas-liquid ratio is approximately 0.9.

[0169] Since the obtained graphene superparticles appear as loose agglomerates held together only by van der Waals forces, these may be broken down under moderate shear forces. Such forces occur, for example, in the cyclone separator of a spray dryer. Therefore, the graphene superparticles are removed directly below the spray chamber, and any particles downstream of the cyclone separator are discarded. These are merely fragments of the graphene superparticles.

[0170] Figure 7 This displays a SEM image of the graphene superparticle.

[0171] Figure 8 This indicates the existence of a wide range of particle sizes, which do not adversely affect the processability of graphene materials.

[0172] The particle size distribution of the graphene superparticles produced according to the present invention is from Figure 7 and 8 This is evident. The graphene superparticle has a diameter on the order of 40 µm.

[0173] Example 2: First graphene pure graph 20

[0174] The graphene material used is First Graphene pure graph 20 (from First Graphene, Henderson, Australia).

[0175] Figure 9 This displays a SEM image of the graphene material. It is shown in the form of small plates, some of which are in the form of agglomerates.

[0176] Figure 10 Displays the corresponding particle size distribution.

[0177] The following characteristic diameter is measured here: d 10 13 µm, d 50 22 µm, d 90 40 µm.

[0178] Production of dispersions:

[0179] The following production process produces a dispersion consisting of water, First Graphene pure graph 20 (from First Graphene, Henderson, Australia) and AEROXIDE® Alu 65 (from Evonik, Essen, Germany).

[0180] Use appropriate additives TEGOMER ® DA 850 (from Evonik, Essen, Germany) was dissolved in water. First Graphene pure graph 20 was added with stirring until a 25% by weight ratio was achieved. The dispersion was then dispersed using an H7 ultrasonic fingertip. The device was set to 100% amplitude and 0.75 cycles. Dispersion was initially carried out for 5 minutes. The container was then closed and vigorously shaken for 30 seconds. This procedure was repeated a total of 3 times.

[0181] Once a homogeneous dispersion is obtained, it is stirred to prevent segregation. This is done using a stirring plate and a soccer ball-shaped stirring rod at 600 rpm.

[0182] Even during step (c), the dispersion is stirred to prevent separation. The process parameters for step (c) are:

[0183] Inlet temperature: 140℃, outlet temperature: 90℃, nozzle gas flow rate: 366 l / min

[0184] Inspirator power 50% (approximately 20 m³ / h), pump power 50% (approximately 8 ml / min).

[0185] The gas-liquid ratio is approximately 0.85.

[0186] Since the obtained graphene superparticles appear as loose agglomerates held together only by van der Waals forces, these may be broken down under moderate shear forces. Such forces occur, for example, in the cyclone separator of a spray dryer. Therefore, the graphene superparticles are removed directly below the spray chamber, and any particles downstream of the cyclone separator are discarded. These are merely fragments of the graphene superparticles.

[0187] Figure 11 This displays a SEM image of the graphene superparticle.

[0188] Figure 12 This indicates the existence of a wide range of particle sizes, which do not adversely affect the processability of graphene materials.

[0189] The particle size distribution of the graphene superparticles produced according to the present invention is from Figure 11 and 12 This is evident. The graphene superparticle has a diameter on the order of 80 µm.

[0190] Example 3: Avanzare av PLAT 2

[0191] The graphene material used is Avanzare av PLAT 2 (from Avanzare, LaRoija, Spain).

[0192] Figure 13 This displays a SEM image of the starting graphene material. It is shown in the form of small plates, some of which are in the form of agglomerates.

[0193] Figure 14 Displays the corresponding particle size distribution.

[0194] The following characteristic diameter is measured here: d 10 0.9 µm, d 50 2.7 µm, d 90 13 µm.

[0195] Production of dispersions:

[0196] The following production process produces a dispersion consisting of water and Avanzare av PLAT 2 (from Avanzare, LaRoija, Spain).

[0197] Use appropriate additives TEGOMER ®DA 850 (from Evonik, Essen, Germany) was dissolved in water. Avanzare av PLAT 2 (from Avanzare, LaRoija, Spain) was added with stirring until a 30% by weight ratio was achieved. The dispersion was then dispersed using an H7 ultrasonic fingertip. The device was set to 100% amplitude and 0.75 cycles. Dispersion was initially carried out for 5 minutes. The container was then closed and the device was shaken vigorously for 30 seconds. This procedure was repeated a total of 3 times.

[0198] Once a homogeneous dispersion is obtained, it is stirred to prevent segregation. This is done using a stirring plate and a soccer ball-shaped stirring rod at 600 rpm.

[0199] Even during step (c), the dispersion is stirred to prevent separation. The process parameters for step (c) are:

[0200] Inlet temperature: 220℃, outlet temperature: 95℃, nozzle gas flow rate: 366 l / min

[0201] Inspirator power 50% (approximately 20 m³ / h), pump power 30% (approximately 8 ml / min).

[0202] Since the obtained graphene superparticles appear as loose agglomerates held together only by van der Waals forces, these may be broken down under moderate shear forces. Such forces occur, for example, in the cyclone separator of a spray dryer. Therefore, the graphene superparticles are removed directly below the spray chamber, and any particles downstream of the cyclone separator are discarded. These are merely fragments of the graphene superparticles.

[0203] Figure 15 This displays a SEM image of the graphene superparticle.

[0204] Figure 16 This indicates the existence of a wide range of particle sizes, which do not adversely affect the processability of graphene materials.

[0205] The particle size distribution of the graphene superparticles produced according to the present invention is from Figure 11 and 12 This is evident. The graphene superparticle has a diameter on the order of 90 µm.

[0206] The particle has a diameter of 37.3 m. 2 / g of BET surface area.

[0207] Example 4: Avanzare av PLAT 2 and AEROXIDE® Alu 65

[0208] The graphene material used is Avanzare av PLAT 2 (from Avanzare, LaRoija, Spain).

[0209] Figure 13 This displays a SEM image of the graphene material. It is shown in the form of small plates, some of which are in the form of agglomerates.

[0210] Figure 14 Displays the corresponding particle size distribution.

[0211] The following characteristic diameter is measured here: d 10 0.9 µm, d 50 2.7 µm, d 90 13 µm.

[0212] Production of dispersions:

[0213] The following production process produces a dispersion consisting of water, Avanzare av PLAT 2 (from Avanzare, LaRoija, Spain) and AEROXIDE® Alu 65 (from Evonik, Essen, Germany).

[0214] Use appropriate additives TEGOMER ® DA 850 (from Evonik, Essen, Germany) was dissolved in water. First Graphene pure graph 20 was added with stirring until a 30% by weight ratio was achieved. The dispersion was then dispersed using an H7 ultrasonic fingertip. The device was set to 100% amplitude and 0.75 cycles. Dispersion was initially carried out for 5 minutes. The container was then closed and vigorously shaken for 30 seconds. This procedure was repeated a total of 3 times.

[0215] Once a homogeneous dispersion is obtained, it is stirred to prevent segregation. This is done using a stirring plate and a soccer ball-shaped stirring rod at 600 rpm.

[0216] Even during step (c), the dispersion is stirred to prevent separation. The process parameters for step (c) are:

[0217] Inlet temperature: 220℃, outlet temperature: 95℃, nozzle gas flow rate: 366 l / min

[0218] Inspirator power 50% (approximately 20 m³ / h), pump power 30% (approximately 8 ml / min).

[0219] Since the obtained graphene superparticles appear as loose agglomerates held together only by van der Waals forces, these may be broken down under moderate shear forces. Such forces occur, for example, in the cyclone separator of a spray dryer. Therefore, the graphene superparticles are removed directly below the spray chamber, and any particles downstream of the cyclone separator are discarded. These are merely fragments of the graphene superparticles.

[0220] Figure 17 This displays a SEM image of the graphene superparticle.

[0221] Figure 18 This indicates the existence of a wide range of particle sizes, which do not adversely affect the processability of graphene materials.

[0222] The particle size distribution of the graphene superparticles produced according to the present invention is from Figure 17 and 18 This is evident. The graphene superparticle has a diameter on the order of 90 µm.

[0223] The particle has a diameter of 137.1 m. 2 / g of BET surface area.

[0224] Example 5: Flowability and Dust Content

[0225] Liquidity

[0226] To quantitatively assess the flowability of the graphene superparticles obtained in Example 1, the following were measured in each case: Hausner factor according to ASTM 527, dynamic avalanche angle and slope angle according to ISO 4324.

[0227] Table 3 shows the compaction density and packing density associated with the Hausner factor from Example 1.

[0228] Table 3: Stretch density, bulk density, and Hausner factor of graphene materials and graphene superparticles produced according to the present invention.

[0229]

[0230] A comparison of the packing density and compacted density of the graphene superparticles produced according to the present invention with those of graphene-based materials shows a significant increase after spray drying.

[0231] In the case of graphene superparticles produced according to the present invention, a lower Hausner factor and therefore lower compatibility were found.

[0232] Table 4 shows the slope angle and dynamic avalanche angle of the graphene material used, according to ISO 4324, by comparing the values ​​with those of graphene superparticles.

[0233] Table 4: Slope Angle and Dynamic Avalanche Angle

[0234]

[0235] The graphene-based material exhibits such poor flow properties and significant smearing in the chamber that optical evaluation of the dynamic avalanche angle is impossible.

[0236] Therefore, it is clear that the method according to the present invention yields graphene superparticles with better fluidity.

[0237] Dust values ​​were determined according to DIN 55992-1 (June 2006 version).

[0238] In this invention, dust values ​​are measured using a Heubach Dustmeter Type I dust evolution apparatus via a rotation method according to DIN 55992 (June 2006 version), and are shown schematically. Figure 1 The construction details of this device are known to those skilled in the art.

[0239] For this determination, 5 g of powder material was introduced as the sample weight into the chamber of the Dustmeter. The chamber was equipped with paddles to keep the powder in motion. The filter unit was weighed before and after the measurement. A constant gas flow rate of 20 l / min was passed through the powder. The chamber rotated at 30 revolutions per minute.

[0240] The dust value is calculated as the ratio of the powder mass in the filter after the experiment to the initial powder mass loaded in the chamber. This means the mass of dust released from the sample weight by the dust evolution device with standard settings.

[0241] The mass of dust released from the sample weight by a dust evolution device with standard settings is reported as a percentage of weight based on the sample weight.

[0242] Table 5 shows the measured dust values.

[0243] Table 5: Graphene materials or materials produced therefrom according to the present invention

[0244] Dust levels of graphene superparticles

[0245]

[0246] It has been found that the graphene superparticles according to the invention have a lower dust value than untreated graphene-based materials. In the case of particles according to the invention, the stability of the graphene superparticles is improved, especially at the surface, because the gaps between the smaller particles of the graphene material used are filled.

[0247] Example 4: Effect of the alumina used

[0248] Graphene superparticles were produced according to Example 2, except that a different commercially available alumina was used. Measurements of the compaction density, bulk density, Hausner factor, slope angle, and dynamic avalanche angle of the functionalized superparticles according to Examples 3 and 5, performed according to Examples 2 and 4, did not show any significant changes compared to the measurements of the graphene superparticles according to Example 2.

[0249] Example 5: Thermal conductivity and electrical insulation

[0250] The graphene superparticles of the present invention according to Example 2, the First graphenepure graph 20 particles used in Example 2, and the alumina particles were each separately introduced into an epoxy resin matrix in an amount of 20% by weight. The thermal conductivity and electrical insulation of the resulting products were examined using the test methods described above. The results showed that... Figure 19 As can be seen from the figure, the superparticles according to the invention exhibit a thin-film resistance several orders of magnitude higher than that of uncoated First graphene pure graph 20, without a significant decrease in thermal conductivity. A significant improvement in thermal conductivity is achieved compared to pure alumina. Furthermore, it has been surprisingly found that electrical insulation is additionally improved compared to pure alumina.

[0251] Therefore, the superparticles produced by the method according to the invention have improved electrical insulation without poor thermal conductivity. Attached Figure Description

[0252] Figure 1 Heubach Dustmeter Type I Dust Evolution Device.

[0253] Figure 2 : A schematic diagram of a preferred method according to the present invention.

[0254] Figure 3 A schematic diagram of the hypothetical formation process of graphene superparticles F, J, and P according to the present invention after step c.

[0255] Figure 4a : Functional principle of a rotary powder analyzer (illustrated).

[0256] Figure 4b : A schematic diagram of the preferred spray dryer.

[0257] Figure 5 : Gamor GO starting materials.

[0258] Figure 6Particle size distribution of Gamor GO starting material measured in water, stirrer speed 6, sonication for 1 minute, circulation speed 6.

[0259] Figure 7 Spray-dried Gamor GO graphene superparticles.

[0260] Figure 8 Particle size distribution of Gamor GO superparticles measured in water, with a stirrer speed of 6, sonication for 1 minute, and a circulation speed of 6.

[0261] Figure 9 First Graphene pure graph 20 starting material.

[0262] Figure 10 Particle size distribution of the first graphene pure graph 20 starting material measured in water, with stirrer speed 6, sonication for 1 minute, and circulation speed 6.

[0263] Figure 11 Spray-dried First Graphene pure graph 20 60 wt% + 40 wt% AEROXIDE ® Alu 65 graphene superparticles.

[0264] Figure 12 First Graphene pure graph 20 60 wt% + 40 wt% AEROXIDE ® Particle size distribution of Alu 65 graphene superparticles.

[0265] Figure 13 : Avanzare av PLAT 2 starting materials.

[0266] Figure 14 : Avanzare av PLAT 2 Particle size distribution of starting material.

[0267] Figure 15 Spray-dried Avanzare av PLAT 2 superparticles.

[0268] Figure 16 : Avanzare av PLAT 2 superparticle particle size distribution.

[0269] Figure 17 Spray-dried Avanzare av PLAT 2 60 wt% + 40 wt% AEROXIDE ®Alu 65 graphene superparticles.

[0270] Figure 18 Avanzare av PLAT 2 60% by weight + 40% by weight AEROXIDE ® Particle size distribution of Alu 65 graphene superparticles.

[0271] Figure 19 The graphene superparticles (■) of the present invention and the primary particles of pure First Graphene 20 (■) ) and primary particles of pure alumina ( The comparison of the sheet resistance to thermal conductivity in each case for 20% by weight of particles in epoxy resin.

Claims

1. A method for producing graphene superparticles, which is carried out through the following steps: (a) mixing at least one graphene material having a particle diameter d 50 of 0.5 pm to 100 pm into a solvent, and (b) Add to the dispersion obtained in step (a) Based on the mass of the graphene material used, 0-100% by weight, preferably 0.1-100% by weight, of dispersing agents, wetting agents, emulsifiers, and / or defoamers. and subsequently (c) Remove at least part of the solvent from the dispersion obtained in step (b) by spray drying. And thus obtained graphene superparticles.

2. The method according to claim 1, wherein at least one additional material (a1) is used simultaneously or sequentially in step (a), which is selected from graphene materials, or SiO2, alumina, TiO2, MgO, ZnO, SbO, organic fillers, or polymers, or phosphates (esters), chlorides, sulfates (esters), nitrites (esters). and wherein the particle diameter d of the at least one further material is at least 10 times smaller than the particle diameter d of the at least one first material 50 at least 10 times smaller.

3. The method according to claim 2, wherein the amounts of graphene material and the other material (a1) in step (a) are 50:50, preferably 60:40, and more preferably 80:

20.

4. The method according to any one of the preceding claims, wherein the spray drying in step (c) comprises the following: The dispersion obtained in step (b) is sprayed into an inert gas stream using a spray unit, wherein the solvent in the droplets formed by the spray evaporates at least partially.

5. The method according to any one of the preceding claims, wherein the method further comprises step (d), said step (d) including... (d) The obtained graphene superparticles are depolymerized in a matrix material, preferably a polymer, monomer or solvent, by shear force, thereby making the graphene particles uniformly distributed in the matrix material.

6. The method according to any one of the preceding claims, wherein the solvent in step (a) is selected from water, distilled water and alkanols, preferably ethanol.

7. The method according to any one of the preceding claims, wherein step (c) yields a diameter d having a diameter of 1 µm to 500 µm, preferably 5 µm to 250 µm, more preferably 50 µm to 100 µm. 50 Graphene superparticles.

8. The method according to any one of the preceding claims, wherein the mass percentage of graphene in the dispersion used in step (b) is from 5% to 50% by weight.

9. The method according to any one of claims 1 to 8, wherein the spray unit in step (c) is a device having at least one two-phase nozzle. And / or the inert gas used is nitrogen, preferably dried nitrogen. The temperature of the inert gas stream is further preferably set between 200°C and 400°C, which is above the cooling limit temperature of the solvent. Further optimization is achieved within the temperature range of 220℃ to 300℃. And / or the sprayed droplets have a size of 30 to 1000 µm.

10. Graphene superparticles obtained according to at least one of claims 1-9, characterized in that... Angle of repose of 50° to 20°, preferably 40° to 25° according to ISO 4324. The dynamic avalanche angle from 65° to 30° according to ISO 4324. 1.5 to 1 according to the Hausner factor of ASTM 527, and / or Dust values ​​from 10 to 0.001 according to DIN 55992 Type I.

11. The graphene superparticles according to claim 10, wherein the amount of graphene in the graphene superparticles is at least 50% by weight.

12. Use of the graphene superparticles according to claim 10 or 11, or the graphene superparticles obtained according to at least one of claims 1 to 9, for use in... - Thermally conductive materials and adhesives, such as thin films, undercurrent materials, castable electronic materials, phase change materials, thermal pastes, and encapsulation formulations, especially in the fields of batteries, sensors, ICs, and LEDs. - Composite materials based on thermoplastics, thermosetting materials, and / or elastomers, which have increased electrical and / or thermal conductivity or are used for EMI shielding, particularly in the enclosures of electrical components, motors, battery packs, and pipes. - Coatings and varnishes with thermal and / or electrical conductivity, or for applications in EMI shielding. - Thermally and / or electrically conductive oil, coolant, or ink.

13. Use of the graphene superparticles according to claim 10 or 11, or the graphene superparticles obtained according to at least one of claims 1 to 9, for use in... - Thermoplastics selected from standard thermoplastics, preferably PE, PP, PS, PVC, α-olefins, butadiene derivatives and / or Vestenamer. ® , - Industrial thermoplastics, preferably PET, PMMA, PC, POM, PA, PBT, PEBA, TPU, PU and / or TPE. - High-performance thermoplastics, preferably PPS, PEEK, PES, PI and / or PEI. - Copolymers, elastomers, preferably silicones, more preferably room temperature crosslinking (RTV) silicones, high temperature crosslinking (HTV) silicones, liquid silicone rubbers (LSR), heat-crosslinking rubbers (HCR), acrylates, and / or pastes containing polysiloxanes and oligosiloxanes. - Polyurethane, rubber, preferably styrene-butadiene rubber (SVR), butadiene rubber (BR) and / or natural rubber, thermosetting materials, preferably polyurethane, polyester resin, phenolic resin, epoxy resin, acrylate resin and / or silicone resin. - Solvent, preferably aprotic-nonpolar, aprotic-polar, and / or protic solvents. - Oil, preferably mineral oil, silicone oil and / or processing oil.

14. The use of graphene superparticles according to claim 10 or 11, or graphene superparticles obtained according to at least one of claims 1 to 9, as an additive in the plastics processing industry, preferably in a mixing machine, in extrusion, or in injection molding.

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