Polyalkylene oxides as dispersant for graphene material

Abstract

The present invention provides the use of a polyepoxide having at least one aromatic group as a dispersant for graphene materials; a method for dispersing graphene materials, wherein the aforementioned polyepoxide is used as a dispersant; and a composition comprising the aforementioned dispersant and graphene materials.

Description

Technical Field

[0001] This invention relates to polyepoxides as dispersants for graphene materials. Prior Technology

[0002] Graphene materials are used in a wide range of technical fields. Graphene and its production, properties and uses are discussed in detail in the technical literature (see Römpp online, https: / / roempp.thieme.de / lexicon / RD-07-02758; Angew. Chem. Int. Ed. 2014, 53, 7714-7718; Mater. Today 2012, 15(3) 86-97).

[0003] Graphene materials are commercially available in powder form and often have extremely low bulk densities, for example, in the range of 2 to 400 g / L. In addition to their low bulk density, graphene materials also exhibit poor flowability and / or generate high dust content when transferred by gravity-driven flow. This leads to poor handling properties, problems during weighing and metering, and must be considered critical from both environmental and occupational safety perspectives. Closed systems for loading solids also have limited effectiveness because, while they may address occupational safety issues, they do not solve the "bridging" problem during continuous or semi-continuous metering of graphene materials in dispersion containers, kneaders, or extrusion lines. Bridging is understood as the uniform metering of solids that leads to feeder blockage, requiring opening and mechanical clearing, which is undesirable. Therefore, volumetric metering is often completely impossible, and gravimetric metering is compromised.

[0004] For example, poor processing is evident when powdered graphene is incorporated into solvents and monomer resins used in thermal interface materials, sealants, and adhesives. Incorporating graphene into liquid systems is generally a challenge. For instance, the production of well-filled sealants and adhesives often depends on incorporating powdered fillers at the right time and during the right period. The shear forces acting on this mixing process break down filler agglomerates, thus aiding dispersion. Therefore, the maximum achievable filler content is essentially determined by the shear forces acting upon it. Solvents and resins themselves can only improperly attach to and stabilize newly formed surfaces and functional groups, leading to separation and sedimentation. This can prevent the acquisition of a usable, stable dispersion for one-step formulation. Furthermore, accurate and reliable metering is important for sealants and adhesives with easily controllable viscosity to achieve good interfacial contact during use, resulting in strong adhesion or high thermal and electrical conductivity. The properties of the adhesive or sealant, and the desired intensity of the effect, such as increased thermal or electrical conductivity, are highly dependent on the dispersibility of the filler and its influence on the overall formulation properties (e.g., viscosity). These considerations also apply to other liquid systems.

[0005] However, producing stable dispersions of graphene materials is difficult. Graphene materials have a tendency to aggregate. These aggregates lead to sedimentation, which is undesirable.

[0006] To improve the dispersibility of graphene materials in solid and liquid systems, previous techniques have proposed the use of dispersants.

[0007] WO 2012 / 059489 A1 discloses, for example, polymer compositions, particularly polymer compositions for thermoplastics or thermosets, comprising a conductive carbon substrate, such as carbon black, carbon fiber, graphite, graphene, and / or CNTs (carbon nanotubes), and salts having non-metallic cations or synergistic mixtures of such salts and metal salts, wherein they must be used in combination with a special dispersant. Such special dispersants are ester- or amide-based dispersants. Preferably, the dispersant is selected from the following: c1) A polyacrylate that can be produced by transesterification of a polyalkyl acrylate with the following, wherein the polyalkyl acrylate can be obtained by polymerization, and the alkyl group of the polyacrylate contains 1 to 3 carbon atoms. a) Saturated fatty alcohols having 4 to 50 carbon atoms and / or b) Unsaturated fatty alcohols with 4 to 50 carbon atoms, The amounts used in a) and b) can achieve transesterification of 30% to 100% of the ester groups. and / or c2) Polyester-polyamine condensation products that can be obtained by partial or complete reaction of the following. A) One or more amino-functionalized polymers containing at least four amino groups and B) Polyesters of one or more general formulas (I) / (Ia) C) One or more polyethers of general formula (II) / (IIa) in T is a hydrogen group and / or, where applicable, a substituted straight-chain or branched aryl, aralkyl, alkyl, or alkenyl group having 1 to 24 carbon atoms. A is a divalent group selected from straight-chain, branched, cyclic, and aromatic hydrocarbons. Z is at least one group selected from the group consisting of: sulfonic acids, sulfuric acids, phosphonic acids, phosphoric acids, carboxylic acids, isocyanates, epoxides, especially phosphoric acid and (meth)acrylic acid. B is a group of general formula (III) SO = -CH₂-CH(Ph)-O-, where Ph = phenyl. a, b, c are independent values ​​from 0 to 100. The condition is that the sum of a+b+c ≥ 0, preferably 5 to 35, especially 10 to 20, and the condition is that the sum of a+b+c+d > 0. d is ≥0, preferably 1 to 5. l, m, and n are independently ≥2, preferably 2 to 4. x and y are independently ≥2.

[0008] Examples of the dispersant c1) described are the commercially available products Tegoner® DA 100 N (Evonik), Tegoner® DA 102 (Evonik), and Tegoner® P121 (Evonik). Examples of the dispersant c2) mentioned are the commercially available product Tegoner® DA 626 (Evonik). Thus, many different dispersants have been disclosed, suitable for dispersing many different carbon substrates. Combinations of graphene materials with polyepoxides containing at least one aromatic group are not disclosed.

[0009] Other commercially available polyester-polyamine condensation products are also known from the prior art, such as Solsperse® 39000 (Lubrizol). Solsperse® 39000 does not contain aromatic groups.

[0010] EP 1078946 A1 describes a polyepoxide block copolymer containing styrene oxide obtained by alkoxylation, and its use as a low-foaming pigment wetting agent in aqueous pigment pastes, and water-based and low-solvent paints and printing inks, where applicable. Many inorganic and organic pigments are mentioned as pigments. It is particularly suitable as a dispersing additive for the production of aqueous (gas) carbon black pastes. Specifically, it describes a black paste containing carbon black (Raven® 1170) in addition to the polyepoxide. However, graphene materials are not disclosed.

[0011] Therefore, there remains a need for dispersants for graphene materials that possess at least one advantage over prior art. More specifically, such dispersants should allow for high filler content in the graphene material and permit stable dispersions with low viscosity. Furthermore, the dispersant should allow the graphene material to be dispersed in both polar and nonpolar, continuous, preferably liquid phases, wherein the continuous, preferably liquid phase should more particularly be a solvent, monomer, oligomer, or polymer composition.

[0012] Now, it has been surprisingly discovered that this objective is achieved by using a polyepoxide having at least one aromatic group as a dispersant for graphene materials. Summary of the Invention

[0013] Therefore, the present invention first provides the use of polyepoxides having at least one aromatic group as dispersants for graphene materials.

[0014] The present invention further provides a method for dispersing graphene materials, characterized in that the polyepoxide system used in the present invention is used as a dispersant.

[0015] The present invention further provides a composition comprising or consisting of the following: (a) Continuous phase, (b) Dispersants corresponding to the uses according to the present invention, and (c) Graphene materials.

[0016] The present invention further provides a composition comprising or consisting of the following: (i) a dispersant corresponding to the use according to the invention, and (j) Graphene materials.

[0017] Advantageous configurations of the subject matter of this invention can be inferred from the claims, embodiments, and specification. Furthermore, disclosures explicitly indicating their relevance to the subject matter include all combinations of the various features described in the invention and the claims. More specifically, a specific embodiment of one subject matter of this invention may be applied by analogy to specific embodiments of other subjects of this invention.

[0018] The inventors have determined that using polyepoxides having at least one aromatic group as dispersants for graphene materials has many advantages.

[0019] One advantage of this invention is the improved dispersibility of graphene materials in the following categories: both polar and nonpolar, continuous, preferably liquid phase, particularly selected from the group consisting of solvents, monomers, oligomers, or polymer compositions. Conversely, as is known from the prior art, dispersants used for graphene materials are only compatible with a very limited number of continuous phases, and even at extremely high dispersant concentrations, they are prone to stratification or low dispersion efficiency.

[0020] Another advantage of this invention is that it yields dispersions with a high filler content of graphene material. This high filler content allows for the achievement or improvement of electrical and thermal conductivity in the dispersion.

[0021] Another advantage of this invention is improved formulation handling and metering, especially compared to graphene powder.

[0022] Another advantage of this invention is improved safety of the process, especially compared to powdered graphene materials.

[0023] Another advantage of this invention is the selective adjustment of the viscosity of compositions containing graphene materials. This is because viscosity typically increases dramatically during the dispersion of graphene materials, potentially causing the composition to solidify and rendering it unusable. On the other hand, at extremely low viscosities, shear effects cannot be generated in a targeted manner during dispersion. This results in inefficient dispersion processes and insufficient dispersion of the graphene material. In contrast, the polyepoxide system used according to this invention acts as a viscosity modifier and allows for selective viscosity adjustment to enable effective dispersion at both low and high viscosities, resulting in stable, highly loaded dispersions of the graphene material.

[0024] Another advantage of this invention is that the polyepoxide used according to the invention does not adversely affect the intrinsic properties of the graphene material. Incorporating this dispersion into thermoplastic, thermosetting, or elastomeric polymer systems used as adhesives and sealants is significantly easier, or even possible from the outset. Implementation

[0025] The subject matter of this invention and its preferred embodiments are described below by way of example, and are not intended to limit the invention to these illustrative embodiments. Where scopes, formulas or compound categories are specified below, this is intended to include the corresponding scope or group of compounds explicitly mentioned, as well as all sub-scopes and subgroups of compounds that can be obtained by subtracting individual values ​​(scopes) or compounds. Any embodiment that can be obtained by combination of scopes / sub-scopes and / or groups / subgroups is fully within the scope of this disclosure and is considered to be explicitly, directly and clearly disclosed.

[0026] Unless otherwise stated, all average values ​​described below are numerical averages. Unless otherwise stated, all measured values ​​or material properties described below are obtained at 25°C and preferably at a pressure of 101,325 Pa (standard pressure). Room temperature (RT) is understood to mean a temperature of 25°C.

[0027] Where numerical ranges are described below in the form of "from X to Y" or "X to Y", where X and Y represent the boundaries of the range, this is synonymous with the description "from at least X to up to and including Y" unless otherwise stated. Therefore, unless otherwise stated, the range thus includes the boundaries of the range X and Y.

[0028] All possible isomers are included in this invention, provided that the molecule / molecular fragment has one or more stereocenters or can differentiate into isomers due to symmetry or other effects (e.g., restricted rotation).

[0029] The word "poly" contains compounds consisting of at least two monomer units.

[0030] The prefix "CxCy" indicates a compound or group having x to y carbon atoms. Therefore, naming a "C1-C20 organic group" signifies an organic group, i.e., an organic group having 1 to 20 carbon atoms. Similarly, naming a "C1-C8 acetyl" group indicates an acetyl group having 1 to 8 carbon atoms. Likewise, naming a "C1-C8 alkyl" group indicates an alkyl group having 1 to 8 carbon atoms. Finally, naming a "C6-C13 hydrocarbon" group refers to a hydrocarbon group having 6 to 13 carbon atoms.

[0031] The following chemical formulas describe compounds or structural units that may be composed of repeating units (e.g., repeating fragments, blocks, or monomers) and may have a molar mass distribution. The frequency of these repeating units is expressed exponentially. Unless otherwise stated, the corresponding exponent is the numerical average (number average) of all repeating units. Therefore, unless otherwise stated, the exponents used for these units in the chemical formula should be considered as statistical averages (numerical averages). Therefore, unless otherwise stated, the exponents used and the numerical range of the exponents described are understood as the average of the possible statistical distributions of actual structures and / or mixtures thereof. The repeating units in the following chemical formulas may have any desired distribution. The structure composed of these repeating units may have any number of blocks and any sequence of block structures, or may be randomly distributed; it may also have alternating structures or form a gradient along the chain, one of which exists; in particular, it may also form any mixed form, in which groups with different distributions may be followed by each other. A particular specific embodiment may result in a limited statistical distribution due to that specific embodiment. The statistical distribution remains unchanged for all regions unaffected by this restriction.

[0032] The present invention first provides the use of polyepoxides having at least one aromatic group as dispersants for graphene materials.

[0033] The plural "polyepoxide" here refers to one or more polyepoxides, preferably one or more polyepoxides.

[0034] The singular "graphene material" refers to one or more graphene materials, preferably one type of graphene material.

[0035] The use of "polyepoxides having at least one aromatic group as dispersants for graphene materials" is therefore synonymous with "polyepoxides having at least one or more aromatic groups as dispersants for one or more graphene materials".

[0036] The use of "polyepoxide having at least one aromatic group as a dispersant for graphene materials" is therefore synonymous with "at least one polyepoxide having at least one aromatic group as a dispersant for at least one graphene material".

[0037] Therefore, the polyepoxide is also referred to hereinafter as a dispersant. Thus, the dispersant is composed of a polyepoxide usable according to the present invention.

[0038] To achieve the objectives of this invention, the polyepoxides used according to this invention must have at least one aromatic group. Without being bound by any particular theory, it is assumed that the aromatic group improves the interaction between the polyepoxide and the graphene material.

[0039] The at least one aromatic group is preferably phenyl.

[0040] To achieve the best results, the mass percentage of all aromatic groups, based on the total mass of the dispersant, is preferably 2% to 40%, more preferably 5% to 25%, and especially 7% to 15%.

[0041] The polyepoxide includes the (A) unit. The groups RA, RB, RC, and RD are each independently an organic group or hydrogen (H). Each organic group can be independently linear or branched or cyclic, saturated or unsaturated, aliphatic or aromatic, substituted or unsubstituted, or combinations thereof, where possible (e.g., cycloaliphatic). The condition for this application is the presence of at least one unit in which at least one of the groups RA, RB, RC, and RD is an aromatic group. The organic group is preferably a heteroatom-free hydrocarbon group, particularly a C1-C8 hydrocarbon group. The polyepoxide preferably comprises units in which exactly one of the four groups RA, RB, RC, and RD is phenyl and the other three groups are hydrogen (H). Therefore, the polyepoxide preferably has at least one unit of the formula -O-CH2-CHPh- or -CH2-CHPh-O-, where Ph represents phenyl.

[0042] The polyepoxide is preferably selected from compounds of general formula (B). in: R1 is independently selected from the group of n-valent C1-C20 organic groups in all cases; R2 is independently selected from the group consisting of C1-C8 acetyl, C1-C8 alkyl, and hydrogen in various cases. SO = styrene oxide, PO = propylene oxide, BO = butane oxide, EO = ethylene oxide, n = 1 to 6, preferably 1 to 4, especially 1 to 3 a = 1 to 10, preferably 1 to 5, especially 1 to 3. b = 0 to 50, preferably 0 to 20, especially 0 to 15. c = 0 to 10, preferably 0 to 5, especially 0 to 3. d = 0 to 50, preferably 0 to 20, especially 0 to 15.

[0043] In equation (B), the preferred value is a+b+c+d≥3.

[0044] For example, the polyepoxide is preferably selected from compounds of general formula (C). in: R1 is independently selected from the group of monovalent C6-C13 hydrocarbon groups in all cases; R2 is independently selected from the group consisting of C1-C8 acetyl, C1-C8 alkyl, and hydrogen in various cases. SO = styrene oxide, PO = propylene oxide, BO = butane oxide, EO = ethylene oxide, a = 1 to 1.9, b = 0 to 3, c = 0 to 3, d=3 to 50, The condition is d≥a+b+c.

[0045] In equation (C), the preferred value is a+b+c+d≥3.

[0046] The polyepoxide is preferably selected from compounds of general formula (D). in: R1 is independently selected from the group of n-valent C1-C20 organic groups in all cases; R2 is independently selected from the group consisting of C1-C8 acetyl, C1-C8 alkyl, and hydrogen in various cases. SO = styrene oxide, PO = propylene oxide, BO = butane oxide, EO = ethylene oxide, n = 1 to 6, preferably 1 to 4, especially 1 to 3 a = 1 to 10, preferably 1 to 5, especially 1 to 3. b = 0 to 50, preferably 3 to 20, especially 3 to 15. c=0, d=0.

[0047] In equations (B), (C), and (D), it is preferred that a+b+c+d≥3, more preferably ≥4, and especially ≥5.

[0048] In formulas (B), (C), and (D), SO (styrene oxide) represents the unit of formula (A), wherein exactly one of the four groups RA, RB, RC, and RD is phenyl, and the other three groups are hydrogen (H).

[0049] In formulas (B), (C), and (D), EO (ethylene oxide) represents the unit of formula (A), in which all four groups RA, RB, RC, and RD are hydrogen (H).

[0050] In formulas (B), (C), and (D), PO (propylene oxide) represents the unit of formula (A), wherein exactly one of the four groups RA, RB, RC, and RD is a methyl group, and the other three groups are hydrogen (H).

[0051] In formulas (B), (C), and (D), BO (epoxybutane) represents the unit of formula (A), wherein exactly one of the four groups RA, RB, RC, and RD is ethyl, and the other three groups are hydrogen (H), or exactly two of the four groups RA, RB, RC, and RD are methyl, and the other two groups are hydrogen (H).

[0052] Compounds of the known formulas (B), (C) and (D) among those skilled in the art typically exist in the form of mixtures. Different alkylene oxide monomers and their proportions throughout the polymer enable control of the hydrophobic / hydrophilic balance, such that the dispersant can be selectively adapted to the graphene material and the continuous phase. The EO units are actually hydrophilic here, while the PO, BO and SO units are hydrophobic.

[0053] The arrangement of the alkylene oxide units can occur (for example) randomly or in block form. The alkylene oxide units are particularly preferably arranged in block form. Thus, the polyalkylene oxide is preferably a block copolymer. Thus, the polyalkylene oxide is preferably a block copolymer polyalkylene oxide. Thus, the polyalkylene oxide is preferably a styrene oxide-based polyalkylene oxide block copolymer. Here, the hydrophobic units (such as SO, PO or BO) and the hydrophilic EO units preferably form independent blocks. The hydrophilic EO units preferably form a block that is present in connection to R 2. R 2 is preferably hydrogen (H) here. The hydrophobic units SO, PO and BO are preferably present between the EO block and R 1. Thus, the groups R 1, SO, PO and BO units and the oxygen atom connecting R 1 to the alkylene oxide unit preferably form an adjacent part in the polyalkylene oxide, which is in turn connected to the EO unit capped with R 2. Thus, in one case, preferably d ≥ a + b + c in formulas (B), (C) and (D), and in another case, < a + b + c in formulas (B), (C) and (D). In the first case, the polyalkylene oxide is more hydrophobic, and in the second case, it is more hydrophilic.

[0054] In addition to carbon and hydrogen atoms, R 1 may also contain heteroatoms, which are selected from (for example) N and O, especially N. However, R 1 preferably does not contain SO units, does not contain PO units, does not contain BO units and does not contain EO units. Preferably, R 1 does not contain heteroatoms. R 1 is preferably independently selected from the group of monovalent C 6 - C 13 hydrocarbon groups in each case. Preferably, R 1 is independently linear (i.e., unbranched) or branched or cyclic, saturated or unsaturated, aliphatic or aromatic, or a combination thereof, where possible. More preferably, R 1 is independently a linear or branched saturated aliphatic group in each case. Even more preferably, R 1 is a linear or branched or cycloaliphatic group having 6 to 13 carbon atoms. Even more preferably, R 1 is a linear aliphatic group, which is particularly selected from the group consisting of: n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl and n-dodecyl. Suitable compounds of formulas (B), (C) and (D) and their synthesis are described in EP 1 078 946 A1 and are (for example) commercially available products under the name Tegomer® DA 646.

[0055] The group R1 is derived from the corresponding hydroxyl functional compound R1(OH)n, where n is as defined in formulas (B) and (D). A series of examples of suitable hydroxyl functional compounds R1(OH)n are provided in the examples (see Table 1). Other suitable hydroxyl functional compounds R1(OH)n may be selected from sugars and sugar alcohols, such as the group consisting of glucose, gulol, and sorbitol. Polyglycerol may also be used as the hydroxyl functional compound R1(OH)n.

[0056] R2 preferably does not contain SO, PO, BO, or EO units. R2 is preferably hydrogen (H).

[0057] The number average molecular weight (Mn) of the polyepoxide is preferably from 400 g / mol to 4000 g / mol, more preferably from 500 g / mol to 2500 g / mol, and particularly from 600 g / mol to 1500 g / mol. This number average molecular weight (Mn) is preferably determined by gel permeation chromatography (GPC).

[0058] In addition to oxygen atoms, the polyepoxide may also contain other heteroatoms, such as, for example, nitrogen atoms. However, the polyepoxide preferably does not contain any phosphorus atoms. More preferably, the polyepoxide does not contain any sulfur atoms. Therefore, the polyepoxide also preferably does not contain any other heteroatoms besides oxygen and, if applicable, nitrogen atoms. Therefore, the polyepoxide is preferably composed only of carbon, hydrogen, oxygen, and, if applicable, nitrogen atoms. Therefore, the polyepoxide is preferably composed of carbon, hydrogen, oxygen, and, if applicable, nitrogen atoms. The polyepoxide particularly preferably does not contain any other heteroatoms besides oxygen atoms. Therefore, the polyepoxide particularly preferably consists only of carbon, hydrogen, and oxygen atoms. Therefore, the polyepoxide particularly preferably consists of carbon, hydrogen, and oxygen atoms.

[0059] The graphene material is preferably a graphene material according to ISO-TS 80004-13, and is preferably selected from the group consisting of: single-layer graphene, bilayer graphene, triple-layer graphene, few-layer graphene, multilayer graphene, one-to-ten layer graphene, epitaxial graphene, exfoliated graphene, graphene nanoribbon, graphene nanoplate, graphene nanoplatelet, graphene nanosheet, graphene microsheet, and graphene nanoflake. Nanoflake), graphene quantum dots, graphene oxide, graphene oxide nanosheets, multilayer graphene oxide, and reduced graphene oxide and mixtures thereof, preferably graphene materials having one to ten layers of graphene.

[0060] The graphene material preferably has a carbon content of at least 80%, more preferably at least 90%, and especially at least 95% (carbon mass content based on the total mass of the graphene material).

[0061] The graphene material is preferably a single-layer or multi-layer graphene material, that is, a graphene material containing one or more layers of graphene. More preferably, a graphene material with two to ten layers of graphene is used as a multi-layer graphene material.

[0062] The thickness of the graphene material is preferably less than 10 nm, preferably less than 5 nm, and especially less than 3 nm.

[0063] The bulk density of the graphene material is preferably from 0.01 g / cm³ to 0.10 g / cm³, more preferably from 0.01 g / cm³ to 0.08 g / cm³, and particularly from 0.01 g / cm³ to 0.05 g / cm³.

[0064] The graphene material preferably exists in the form of particles, flakes, powders, films, sheets, plates, nanoribbons and / or fibers.

[0065] Further details about graphene materials and their production, properties and uses can be found in the technical literature (see Römpp online, https: / / roempp.thieme.de / lexicon / RD-07-02758; Angew. Chem. Int. Ed. 2014, 53, 7714-7718; Mater. Today 2012, 15(3), 86-97).

[0066] The graphene material can be dispersed in a continuous liquid phase using the aforementioned polyepoxide. The graphene material is preferably dispersed in a liquid continuous phase comprising compounds selected from the group consisting of: polyethers, especially polyether polyols; polyesters, especially polyester polyols; polycarbonates, especially polycarbonate polyols; polybutadiene, especially polybutadiene polyols; epoxy resins; polysiloxanes; silicone oils; vegetable oils; mineral oils; synthetic organic oils; silicone-modified polymers; silicone-modified reactive diluents; (meth)acrylic acid; (meth)acrylates; cyanoacrylates; dihydro-L-glucanone (Cyrene®); dimethylformamide (DMF); organic carbonates; acetone; ethylene glycol; dimethyl sulfoxide (DMSO); tetrahydrofuran (THF); methyl ethyl ketone (MEK); acetates; N-methyl-2-pyrrolidone (NMP); alcohols and diesters (DBE).

[0067] The preferred vegetable oil is selected from the group consisting of linseed oil, soybean oil, rapeseed oil, castor oil, epoxidized linseed oil, epoxidized soybean oil, epoxidized rapeseed oil, and epoxidized castor oil.

[0068] The silicon-modified polymer preferably has triethoxysilyl and / or trimethoxysilyl groups. The polymer backbone is preferably a polysiloxane (polysiloxane), polybutadiene, or polyether backbone.

[0069] The designation "(meth)acrylic acid" represents methacrylic acid and / or acrylic acid. The designation "(meth)acrylate" represents methacrylate and / or acrylate. (Meth)acrylate is preferably selected from the group consisting of: n-butyl methacrylate, isobutyl methacrylate, cyclohexyl methacrylate, 2-hydroxyethyl methacrylate, 2-ethylhexyl methacrylate, methyl methacrylate, ethyl methacrylate, vinyl methacrylate, n-butyl acrylate, isobutyl acrylate, cyclohexyl acrylate, 2-hydroxyethyl acrylate, 2-ethylhexyl acrylate, methyl acrylate, ethyl acrylate, and vinyl acrylate.

[0070] Organic carbonates are preferably selected from the group consisting of: dimethyl carbonate, propylene carbonate, allyl ethyl carbonate, vinyl carbonate, methyl ethyl carbonate, vinyl carbonate, fluoroethylene carbonate, butyl carbonate, diethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl isopropyl carbonate, dipropyl carbonate, dibutyl carbonate, and chloroethylene carbonate.

[0071] Ethylene glycol is preferably selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, and tetrapropylene glycol.

[0072] The preferred acetates are those selected from the group consisting of methyl acetate, ethyl acetate, n-propyl acetate, and n-butyl acetate.

[0073] The preferred alcohols are selected from the group consisting of ethanol, methanol, propanol, isoamyl alcohol, 1-butanol, isopropanol, phenoxyethanol, and 2-(2-phenoxyethoxy)ethanol.

[0074] Diesters (DBEs) are preferably selected from the group consisting of dimethyl succinate (DBE-4), dimethyl glutarate (DBE-5), and dimethyl adipate (DBE-6). Mixtures are typically used, such as DBE-9, which is a mixture of DBE-4 and DBE-5.

[0075] The continuous phase preferably contains a plasticizer selected from the group consisting of phthalates, citrates and adipates as the main component.

[0076] The continuous phase preferably includes a baking varnish, such as a silica-based baking varnish, as the main component.

[0077] The continuous phase preferably comprises unsaturated polyester resin (UPES) or vinyl ester resin as the main component.

[0078] The continuous phase preferably contains phenolic resin (UF, MUF) or amino resin as the main component.

[0079] The principal component of the continuous phase is understood to be the dominant component of the continuous phase in terms of its mass proportion. The mass proportion of the principal component, based on the total mass of the continuous phase, is preferably at least 50%, preferably at least 90%, particularly 100%, with a maximum of 100%.

[0080] The present invention further provides a method for dispersing graphene materials, characterized in that a polyepoxide as used in the present invention is used as a dispersant.

[0081] The method preferably includes the following indirect or direct sequential method steps, preferably direct sequential method steps: a) First, add the continuous phase; b) Add a dispersant corresponding to the intended use according to the invention; c) Add and disperse graphene materials.

[0082] The method may preferably include the following indirect or direct sequential method steps, preferably direct sequential method steps: i) First, add a dispersant corresponding to the intended use according to the present invention; j) Adding and dispersing graphene materials.

[0083] The term "dispersant" is understood herein to refer to the aforementioned polyepoxide. Therefore, the dispersant is composed of one or more polyepoxides usable according to the present invention.

[0084] This optimal dispersion occurs under shear stress, resulting in high energy input. This leads to polymer breakage and exfoliation, forming fresh, unsaturated surfaces. These attack points—functional groups (such as hydroxyl, carboxyl, aldehyde, ketone, epoxy, and amine groups) and conjugated systems—are suitable for attaching various dispersants and stabilizers. This in-situ addition makes dispersion highly efficient, resulting in higher filler contents and more stable dispersions. Higher filler contents then allow for greater flexibility in formulation for end-use applications such as adhesives, sealants, and thermal interface materials.

[0085] In the method according to the invention, particularly in steps c) and j), various dispersion techniques and equipment can be used, such as equipment selected from the group consisting of: ball mills, dissolvers (e.g., Dispermat® dissolvers), three-roll mills, Ultra-Turrax, wet-jet mills, conchier equipment, high-shear mixers, preferably high-speed mixers and hot mixers. Dispersion can also be accomplished by acoustic vibration. Dispersion is preferably accomplished using a Dispermat® dissolver or a ball mill.

[0086] It is preferable to introduce / apply the power / energy for a period of 0.1 min to 99 h, more preferably for a period of 0.1 min to 2 h, and even more preferably for a period of 1 min to 15 min.

[0087] The method according to the present invention has the advantage of being extremely easy to implement and thus producing a composition of graphene material with a high quality ratio.

[0088] The present invention also provides a composition comprising or consisting of the following: (a) Continuous phase, (b) Dispersants corresponding to the uses of the present invention, and (c) Graphene materials.

[0089] The dispersant is also understood herein to mean at least one of the aforementioned polyepoxides. Therefore, the dispersant is composed of one or more polyepoxides that can be used according to the present invention.

[0090] Based on the mass of the composition, the mass percentage of component (c) is preferably 0.1% to 90%, more preferably 5% to 60%, and particularly 25% to 40%. Therefore, the mass of component (c) divided by the mass of the composition is 0.1% to 90%, preferably 5% to 60%, and particularly 25% to 40%.

[0091] Based on the mass of component (c), the mass proportion of component (b) is preferably 0.01% to 200%, more preferably 30% to 150%, and particularly 50% to 100%. Therefore, the mass of component (b) divided by the mass of component (c) is 0.01% to 200%, more preferably 30% to 150%, and particularly 50% to 100%.

[0092] The present invention also provides a composition comprising or consisting of the following: (i) Dispersants corresponding to the uses according to the present invention, and (j) Graphene materials.

[0093] The dispersant is also understood herein to mean at least one of the aforementioned polyepoxides. Therefore, the dispersant is composed of one or more polyepoxides that can be used according to the present invention.

[0094] Based on the mass of the composition, the mass percentage of component (j) is preferably 0.1% to 90%, more preferably 5% to 60%, and particularly 25% to 40%. Therefore, the mass of component (j) divided by the mass of the composition is 0.1% to 90%, preferably 5% to 60%, and particularly 25% to 40%.

[0095] Based on the mass of component (j), the mass proportion of component (i) is preferably 0.01% to 200%, more preferably 30% to 150%, and particularly 50% to 100%. Therefore, the mass of component (i) divided by the mass of component (j) is 0.01% to 200%, more preferably 30% to 150%, and particularly 50% to 100%.

[0096] The composition of this invention may include other additives, such as fillers to improve electrical conductivity, preferably selected from the group consisting of poly(3,4-ethylenedioxythiophene) (PEDOT), polyaniline, carbon nanotubes, carbon black, carbon fibers, metal particles, metal fibers, silver nanowires, graphite (e.g., expanded graphite), and manganese oxides; fillers to improve thermal conductivity, preferably selected from the group consisting of hBN, AlN, Al₂O₃, SiO₂, ZnO, MgO, SiC, and nanodiamonds; flame retardants; impact modifiers; color pigments; UV stabilizers; viscosity modifiers; anti-caking agents; defoamers; ionic liquids; wetting agents; and / or anti-scratch agents.

[0097] The combination of components (a), (b) and (c) can provide a stable dispersion even with a high filler (c) content, and preferably a dispersion with low viscosity.

[0098] Therefore, the combination of components (i) and (j) also provides a stable dispersion with a high filler (j) content, preferably a dispersion with low viscosity.

[0099] The components of this invention (especially in paste form) are highly versatile and can be used in, for example, the automotive industry, heat exchangers, electronic applications, thermal management, antistatic protection, semiconductor industry, housings, packaging, 3D printing, injection molding components, hose systems, diaphragms, fuel cells, cable systems, for electromagnetic (EMV) shielding, thermal management of battery systems, adhesives and sealants, and potting compounds.

[0100] Furthermore, the composition of the present invention (especially in paste form) is suitable as an additive for the following materials: elastomers, thermosetting materials, thermoplastic materials, and thermoplastic elastomers.

[0101] The compositions of this invention (especially those in paste form) are particularly suitable as additives for the following materials / uses: - Adhesives and sealants (especially those for electrical and / or thermal conductivity), including epoxy resins, phenolic resins, polyurethanes, silane-modified polymers (silicone-modified polymers, SMP), acrylates, reactive hot melts, - Silicon oxide (RTV, HTV, LSR, HCR) - Acrylates, - Polyurethanes, such as thermoplastic polyurethanes, - Rubber, preferably SBR, BR, natural rubber, polybutadiene, or functionalized polybutadiene. - Thermosetting materials, preferably polyurethane, polyester resin, phenolic resin, epoxy resin, acrylate resin, and silicone resin. - Thermal interface materials: gap fillers, tapes, greases and phase change materials, potting compounds, encapsulations, underfills, castings, coatings, protective coatings. - Thermoplastic materials, selected from standard thermoplastics, preferably PE, PP, PS, PVC, α-olefins, butadiene derivatives, and Vestenamer® (Evonik). - Among technical thermoplastics, PET, PMMA, PC, POM, PA, PBT, PEBA, TPU, PU, ​​and TPE are preferred; among high-performance thermoplastics, PPS, PEEK, PES, PI, and PEI are preferred; among copolymers, - Semi-finished products, - In the automotive field: electric drive, thermal management of battery systems, vehicle and external charging infrastructure, electronic and power electronics, fuel cells, sensors, displays, cockpits, interactive surfaces, EMV shielding (electromagnetic shielding) - Electronic and power electronic equipment (connections), - Connections and heat dissipation for microchips, electronic components, displays, and indicators. - Connections and heat dissipation for LED headlamps / spotlights, LEDs, and surface lighting - Communication system connectivity and heat dissipation, - Hydrogen technologies and gas systems requiring antistatic and airtight properties (gaskets, fuel cells, tanks, connectors, plugs, pipes / cables) - Mineral oils, silica oils, processing oils, vegetable oils, modified vegetable oils, motor oils, hydraulic and drive oils, greases, gels, phase change materials, and oils used for electrical and thermal conductivity and to reduce sliding friction.

[0102] In the above-described uses / materials, the composition preferably results in at least one of the following effects: - (Improved) conductivity, - (Improved) thermal conductivity, - Reduce friction, - Improved mechanics, - High scratch resistance - Coloring / pigment, - Absorption of UV radiation, - Antibacterial / antiviral effects - Improved flame retardancy, - Lower breathability.

[0103] [Example] [] []

[0104] The embodiments cited below are merely illustrative of the implementation of the invention for those skilled in the art. They do not constitute any limitation on any of the claimed objectives.

[0105] Dispersant (dispersing additive or simply "additive")

[0106] The following polyepoxides, corresponding to the stoichiometry shown in Table 1, were prepared as dispersants for this invention. Here, the values ​​indicate the molar ratio of the epoxide (SO, PO, BO, EO) to the starting alcohol. Therefore, Additive 4 is based on 1 mol SO, 2 mol BO, 8 mol PO, and 0 mol EO, all calculated as 1 mol hexyl-1-ol in all cases. The starting alcohol and corresponding epoxide were synthesized as described in EP 1078946 A1. The group R1 of the additives in Table 1 is derived from the respective starting alcohol used (e.g., hexyl-1-ol results in R1 = hexyl). The following applies to all additives in Table 1: R2 = H.

[0107] Table 1: Chemical composition of dispersant additives 1 to 18 product Starting material (alcohol) SO PO BO EO Additive 1 Hex-1-ol 1 1 0 8 Additive 2 Hex-1-ol 1 0 1 6 Additive 3 Hex-1-ol 3 10 0 0 Additive 4 Hex-1-ol 1 8 2 0 Additive 5 Oct-1-ol 1 1 0 8 Additive 6 Oct-1-ol 1 0 2 10 Additive 7 Oct-1-ol 3 11 0 0 Additive 8 Oct-1-ol 2 12 1 0 Additive 9 Trimethylolpropane 2 2 0 8 Additive 10 Trimethylolpropane 2 8 0 0 Additive 11 Ethyl-1,2-diol 3 0 0 10 Additive 12 Ethyl-1,2-diol 3 12 0 0 Additive 13 Oct-1-ol 3 0 0 11 Additive 14 Surfynol® 104 (Evonik) (2,4,7,9-Tetramethyl-5-decyn-4,7-diol) 3 8 0 0 Additive 15 Diethylmonoethanolamine 2 15 2 0 Additive 16 Diethylmonoethanolamine 1.5 6 0 0 Additive 17 Hex-1-ol 0 0 0 6 Additive 18 Hex-1-ol 0 2 0 6

[0108] Dispersants that may be used according to the present invention are Additives 1 to 16 . These contain aromatic groups. Dispersants that cannot be used according to the present invention are Additives 17 and 18 and Solsperse® 39000 (Lubrizol) and Tegomer® DA 100 N (Evonik). These do not contain any aromatic groups.

[0109] filler

[0110] Graphene:

[0111] The graphene material used was graphene having the following properties: Dv50 = 20 μm (as measured by laser diffraction), surface resistance ≤10 ohm / square (four-point sample on a 25 μm thin film of this filter diaphragm), and a vibration density of 3 = 0.251 gcm-3 (according to ASTM D7481).

[0112] Carbon Black:

[0113] The filler that cannot be used according to the present invention is carbon black, which can be used to improve the conductivity. Its DBP absorption (DBP=dibutyl phthalate) measured according to ASTM D 2414 was 119 ml / 100 g and the body density measured according to ASTM D1513 was 300 g / dm The CTAB surface area measured for D3765 (CTAB = hexadecyltrimethylammonium bromide) was 135 m 2 / g.

[0114] Produce pastes using a Dispermat® dissolver

[0115] This paste is typically produced intermittently (batch operation) with the aid of a suitable dispersion unit and dissolver (Dispermat® CV4-Plus dissolver, VMA-Getzmann). The paste is produced using a 40 mm diameter dissolver disc in a 250 ml stainless steel container. For the 250 ml stainless steel container, a batch size of 100 g of paste is selected. The stainless steel container contains a defined amount of continuous phase (e.g., polyether polyol, polyester polyol, methyl methacrylate, polybutadiene glycol, etc.) added according to the specific experiment. If a dispersing additive is used, the additive is added to the continuous phase in a defined amount relative to the filler usage (additive on pigment = AoP [%]). "Pigment" and "filler" are understood to refer to graphene materials or carbon black. The following relationships apply to the mass of the continuous phase (mcontinuous phase), the total mass of the composition (mtotal), the mass of the filler (mfiller), the mass of the additive (madditive), the maximum filler content (max), and the mass of the additive relative to the mass of the filler (AoP, additive as pigment):

[0116] The container containing the continuous phase and dispersing additive is clamped in the Dispermat® dissolver assembly, and the stirrer is turned down so that the dissolver disc is present in the continuous phase but does not touch the bottom of the container. To prevent the dispersing additive from settling to the bottom of the stainless steel container, it is stirred into the continuous phase at 750 rpm for 1 minute. The filler is added gradually, part by part. During this addition, the stirrer is set between 750 rpm and 1000 rpm, depending on dust formation. The part-by-part addition is carried out over a period of approximately 5 minutes. At the end of the addition, the rotation speed of the Dispermat® dissolver stirrer is increased to 2000 rpm to 2500 rpm for ideal dispersion. This state is maintained for another 5 minutes until the graphene-based paste is completely dispersed.

[0117] Visually assess the storage stability of the paste.

[0118] 40 g of the paste was placed in a test tube with a bottom diameter of 2.5 cm and stored at room temperature for 12 h and 72 h, then examined. Another sample was stored at 50°C for 72 h and then examined. The examination included a visual inspection of the paste's dehydration and appearance by two people. The amount of paste flowing off a metal spatula was also examined. The following evaluation criteria were used: "unstable" or "stable":

[0119] Unstable (Stability: "None")

[0120] The paste forms a transparent slurry at least 2 mm thick on the surface. The paste appears gritty. The paste cannot flow evenly from the scraper.

[0121] Stable (Stability: "Yes")

[0122] The paste forms a transparent slurry less than 2 mm in diameter. The paste appears uniform and thick. It flows evenly from the spatula.

[0123] Viscosity (rheological study of the paste)

[0124] The viscosity of the paste was determined using a rheometer (Physica MCR 301 / Anton Paar). This study used a transducer-less D-CP / PP7 measuring shaft (Anton Paar) connected to a 25 mm disposable measuring plate (D-PP25 / AL / S07 D: 25 mm disposable measuring plate / Anton Paar). Before starting the measurement, the zero gap was set (here: 0.5 mm). This gap width is used to measure the paste described below. This completes the preparation of the rheometer for the measurement. A defined amount of paste was applied to the rheometer plate, and the preset measuring gap of 0.5 mm was adjusted. Excess paste at the edges was then removed (“trimming the sample”). Measurements were then performed. A linear ramp-up was performed at shear rates from 0.1 s⁻¹ to 1000 s⁻¹. The following conditions / parameters were used: Data points: Specifications: Number: 100 Variables: Shear rate Duration: Linear Slope Profile: Slope (Linear) Starting value: 5s Starting value: 0.1 [1 / s] Final value: 1s Final value: 1000 [1 / s]

[0125] A graphical evaluation is performed by plotting the viscosity against the shear rate. Then, for example, the curves of pastes with and without additives are compared. Typically, only the shear rate values ​​of 1 s⁻¹ and 10 s⁻¹ are compared.

[0126] Hergmann fineness test

[0127] Equipment used: Fineness gauge 25 (PD 1510) Fineness gauge 100 (PD 1512) Groove dimensions: 13 x 130 mm Number of grooves: 2 Scale: µm / Hergmann grade Range: 0 - 25 / 8 - 6 Groove dimensions: 13 x 130 mm Number of grooves: 2 Scale: µm / Hergmann grade Range: 0 - 100 / 8 - 0

[0128] The Hegmann fineness meter is used to determine the dispersibility of particles or agglomerates in a continuous liquid phase. It cannot determine the actual particle size or particle distribution.

[0129] This fineness gauge is a flat steel block with two shallow wedge-shaped grooves cut into its surface. Within these grooves, the depth smoothly progresses from a maximum depth at one end of the gauge to zero at the other end. This wedge depth can be read from a scale engraved on its side. The Hergmann number ranges from 0 to 8, with higher Hergmann numbers indicating smaller particles. The following Hergmann numbers and µm values ​​are specified: 0 Hergmann = 100 µm 4 Hergmann = 50 µm 8 Hergmann = 0 µm

[0130] Place the cleaned and dried fineness gauge on a level, non-slip surface. Fill the deepest point of the groove in the fineness gauge with the paste to be studied. The paste must slightly overflow the edge of the groove. Place the scraper blade parallel to the short side of the groove at the deepest point and quickly pull it vertically to the shallow end of the groove. After smoothing the sample, immediately examine the fineness gauge at an angle of right angle to the long side and 20° to 30° to its surface, lifting it up to light to make the surface structure of the paste in the groove visible. Determine the point where a relatively large number of particles or particle scratches are first seen in the groove and read the relevant scale value (Hegman scale).

[0131] Early disturbances occurring in the grooves (high Hegmann level) indicate that the paste contains, for example, residual agglomerates, or that the filler (i.e., graphene material or carbon black) is poorly dispersed in the continuous phase. Consequently, greater instability of the paste can be expected, as can other disadvantages mentioned above regarding incompletely dispersed graphene in this end use.

[0132] The fineness gauge test was evaluated in other processes as follows: qualified Hergmann Rank (8-7) Small particles, no agglomerates, well-dispersed, stable paste Unqualified Hergmann's rating (7-0) Large particles, agglomerates, poor dispersion, and unstable paste

[0133] Production of graphene paste

[0134] The graphene paste was produced according to the following examples: 1. Add the continuous phase to a 250 ml metal cup. 2. Add the dispersant (100% AoP). Gently stir with a spatula to prevent the additive from settling at the bottom. 3. Using a Dispermat® dissolver, the additive was stirred into the continuous phase at 750 rpm with a 40 mm dispersing disc for approximately 1 minute. 4. Add the filler gradually over a period of approximately 5 minutes at 750-1000 rpm. 5. When the addition of the filler is complete, stir for another 5 minutes at 2000-2500 rpm until the filler is completely dispersed.

[0135] Example 1: Paste based on polyether polyol

[0136] For the production of polyether polyol-based pastes, Desmophen® 1110 BD (Covestro) is used as the continuous phase (see Tables 2 and 3):

[0137]

[0138]

[0139] Example 2: Paste based on polyester polyol

[0140] For the production of polyester polyol-based pastes, Dynacoll® 7250 (Evonik) is used as the continuous phase (see Tables 4 and 5):

[0141]

[0142]

[0143] Example 3: Paste based on polybutadiene glycol

[0144] For the production of butadiene glycol-based pastes, Polyvest® HT (Evonik) is used as the continuous phase (see Tables 6 and 7):

[0145]

[0146]

[0147] Example 4: Epoxide-based paste

[0148] For the production of epoxide-based pastes, Epikote® Resin 828 (Hexion) is used as the continuous phase (see Tables 8 and 9):

[0149]

[0150]

[0151] Example 5: A paste based on methyl methacrylate

[0152] For the production of methyl methacrylate-based pastes, Meracryl® MMA (Röhm) is used as the continuous phase (see Tables 10 and 11):

[0153]

[0154]

[0155] Example 6: Paste based on vegetable oil

[0156] For the production of vegetable oil-based pastes, castor oil is used as the continuous phase (see Tables 12 and 13):

[0157]

[0158]

[0159] Example 7: Paste based on silicon-modified polymer (SMP)

[0160] For the production of pastes based on silicon-modified polymers (SMP), Tegopac® RDS 1 is used as the continuous phase (see Tables 14 and 15):

[0161]

[0162]

[0163] Only the combination of the polyepoxide and graphene materials that can be used according to the present invention results in a composition with high stability and low viscosity (not considering the continuous phase) and produces good results in the Hegmann fineness test.

Claims

1. Use of a polyepoxide having at least one aromatic group as a dispersant for graphene materials, wherein the polyepoxide is selected from compounds of general formula (B), wherein: R1 is independently selected from the group consisting of n-valent C1-C20 organic groups in all cases; R2 is independently selected from the group consisting of C1-C8 acetyl, C1-C8 alkyl and hydrogen in all cases, SO = styrene oxide, PO = propylene oxide, BO = butane oxide, EO = ethylene oxide, n = 1 to 6, a = 1 to 10, b = 0 to 50, c = 0 to 10, d = 0 to 50.

2. As claimed in claim 1, wherein the mass percentage of all aromatic groups is 2% to 40% based on the total mass of the dispersant.

3. As claimed in claim 1, wherein the mass percentage of all aromatic groups is 7% to 15% based on the total mass of the dispersant.

4. As per the purpose of request item 1, where n = 1 to 4, a = 1 to 5, b = 0 to 20, c = 0 to 5, d = 0 to 20.

5. According to the purpose of request item 1, wherein, n=1 to 3, a=1 to 3, b=0 to 15, c=0 to 3, d=0 to 15.

6. As claimed in claim 1, wherein the polyepoxide contains no other heteroatoms other than oxygen and, where appropriate, nitrogen atoms.

7. According to the purpose of claim 1, wherein the graphene material is a graphene material according to ISO-TS 80004-13, selected from the group consisting of: single-layer graphene, bilayer graphene, trilayer graphene, few-layer graphene, multilayer graphene, one-to-ten layer graphene, epitaxial graphene, exfoliated graphene, graphene nanoribbon, graphene nanoplate, graphene nanoplatelet, graphene nanosheet, graphene microsheet, graphene nanoflake, graphene quantum dot, graphene oxide, graphene oxide nanosheet, multilayer graphene oxide, and reduced graphene oxide and mixtures thereof.

8. According to the use of claim 1, wherein the graphene material is dispersed in a liquid continuous phase, the liquid continuous phase comprising compounds selected from the group consisting of: polyethers, polyether polyols, polyesters, polyester polyols, polycarbonates, polycarbonate polyols, polybutadiene, polybutadiene polyols, epoxy resins, polysiloxanes, vegetable oils, mineral oils, synthetic organic oils, silicone-modified polymers, silicone-modified reactive diluents, (meth)acrylates, cyanoacrylates, dihydro-L-glucanone (Cyrene®), dimethylformamide (DMF), organic carbonates, acetone, ethylene glycol, dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), acetates, N-methyl-2-pyrrolidone (NMP), alcohols, and diesters (DBE).

9. A method for dispersing graphene material, characterized in that a polyepoxide is used as a dispersant, wherein the requirements of any one of claims 1 to 8 are applied, wherein the method comprises the following indirect or direct continuous method steps: a) firstly adding a continuous phase as specified in claim 8, b) adding a dispersant as specified in any one of claims 1 to 6, c) adding and dispersing the graphene material as specified in claim 7.

10. The method according to request item 9, wherein the method steps are direct successive method steps.

11. A method for dispersing graphene material, characterized in that a polyepoxide is used as a dispersant, wherein the application of any one of claims 1 to 8 comprises the following indirect or direct sequential method steps: i) firstly adding the dispersant as specified in any one of claims 1 to 6, j) adding and dispersing the graphene material as specified in claim 7.

12. A composition obtained by means of the method according to claim 9 or 10, comprising or consisting of: (a) a continuous phase as specified in claim 8, (b) a dispersant as specified in any one of claims 1 to 6, and (c) a graphene material as specified in claim 7.

13. A composition obtained by the method according to claim 11, comprising or consisting of: (i) a dispersant as specified in any one of claims 1 to 6, and (j) a graphene material as specified in claim 7.

14. The composition according to claim 12 or 13, wherein the mass percentage of component (c) or (j) is from 0.1% to 90% based on the mass of the composition.

15. The composition according to claim 12 or 13, wherein the mass percentage of component (b) or (i) is from 0.01% to 200% based on the mass of component (c) or (j), respectively.