Polyalkylene oxides as dispersants for graphene materials

Abstract

The subject of the present invention is the use of a polyalkylene oxide having at least one aromatic group as a dispersing agent for graphene material; a method for dispersing graphene material, which uses said polyalkylene oxide as a dispersing agent; and a composition comprising said dispersing agent and a graphene material.

Description

[Technical field]

[0001] The present invention relates to polyalkylene oxides as dispersants for graphene materials.

[0002] Graphene materials are used in many technological fields. Graphene and its production, properties and applications are discussed in detail in the technical literature (Roempp 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 as powders and often have a very low bulk density, for example in the range of 2-400 g / l. In addition to the low bulk density, graphene materials either have poor flowability or generate a high dust content when conveyed by gravity flow. This results in poor handling and problems during weighing and metering, which must also be considered critical from the standpoint of environmental protection and occupational safety. Here, closed systems for dosing the solids are likewise of limited effectiveness, since, although they do indeed address the occupational safety issues, they do not solve the so-called bridging problems during continuous or semi-continuous metering of graphene materials in dispersion vessels, kneaders or extrusion lines. Bridging is understood to mean an uneven metering of solids, which can lead to blockage of the feeder, which can then require mechanical release by opening the feeder, which is undesirable. As a result, volumetric metering is often not possible at all and gravimetric metering is impaired.

[0004] The poor handling is also evident, for example, when incorporating powdered graphene materials into solvents or monomer resins of so-called thermal interface materials, sealants, and adhesives. Incorporating graphene materials into liquid systems is generally difficult. For example, in the production of well-filled sealants and adhesives, it is usually important to incorporate the powdered filler at the right time and for the right amount of time. The shear forces acting during the mixing process break up the filler agglomerates and contribute to their dispersion. The maximum achievable loading level is therefore substantially determined by the shear forces acting on it. The solvent or resin by itself does not adequately attach to or stabilize the freshly formed surfaces or functional groups, resulting in separation or settling. As a result, a stable dispersion that can be used for further processing in the formulation may not be obtained. Furthermore, for sealants and adhesives whose viscosity can be easily controlled, accurate and reliable metering is important to achieve good interfacial contact and thus strong adhesion or even thermal or electrical conductivity during use. The quality of an adhesive or sealant and the strength of the effect to be achieved, e.g., improved thermal or electrical conductivity, strongly depends on the dispersion of the filler and its influence on the overall properties of the formulation (e.g., viscosity). The above considerations also apply to other liquid systems.

[0005] However, producing stable dispersions of graphene materials is problematic because graphene materials tend to agglomerate, which can lead to undesirable settling.

[0006] To improve the dispersibility of graphene materials in solid and liquid systems, the prior art has proposed the use of dispersants.

[0007] WO 2012 / 059489 for example discloses polymer compositions, in particular for thermoplastic or thermosetting resins, which comprise electrically conductive carbon substrates, such as carbon black, carbon fibres, graphite, graphene and / or CNTs (carbon nanotubes), and salts with non-metallic cations or synergistic mixtures of such salts with metal salts, in which the combination with specific dispersants is essential. These specific dispersants are ester or amide based dispersants. Here, it is preferred that the dispersants are selected from: c1) a polyacrylic acid alkyl ester obtained by polymerization, the alkyl group of which has 1 to 3 carbon atoms, and a) saturated aliphatic alcohols having 4 to 50 carbon atoms and / or b) Unsaturated aliphatic alcohols having 4 to 50 carbon atoms polyacrylic acid esters which can be prepared by transesterification with and / or c2) Below: A) one or more amino-functional polymers having at least four amino groups; B) General formula (I) / (Ia) TC(O)-[OAC(O)] x -OH (I) TO-[C(O)-AO-] y -Z (Ia) and one or more polyesters C) General formula (II) / (IIa) TC(O)-BZ (II) TOBZ (IIa) and one or more polyethers 1. A polyester-polyamine condensation product obtained by partial or complete reaction of T is a hydrogen group and / or an optionally substituted linear or branched aryl, arylalkyl, alkyl or alkenyl group having 1 to 24 carbon atoms; A is at least one divalent group selected from the group consisting of linear, branched, cyclic and aromatic hydrocarbons; Z is at least one radical selected from the group of sulfonic acid, sulfuric acid, phosphonic acid, phosphoric acid, carboxylic acid, isocyanate, epoxide, in particular phosphoric acid and (meth)acrylic acid, B is a group represented by the general formula (III) -(C l H 2l O) a -(C m H 2m O) b -(C n H 2n O) c -(SO) d (III) Based on SO=-CH2-CH(Ph)-O-, where Ph=phenyl group; a, b, and c are each independently a value between 0 and 100. with the proviso that the sum of a+b+c is ≧0, preferably 5 to 35, in particular 10 to 20, and the sum of a+b+c+d is >0; d≧0, advantageously 1 to 5, l, m and n are independently ≧2, preferably from 2 to 4, A polyester-polyamine condensation product, wherein x, y are, independently of each other, ≧2.

[0008] As examples of dispersants c1), the commercial products TEGOMER® DA 100 N (Evonik), TEGOMER® DA 102 (Evonik) and TEGOMER® P121 (Evonik) are given. As an example of dispersants c2), the commercial product TEGOMER® DA 626 (Evonik) is also given. Thus, a large number of different dispersants are disclosed, which are also suitable for dispersing a large number of different carbon substrates. The combination of a graphene material with a polyalkylene oxide having at least one aromatic group is 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 1 078 946 A1 describes styrene oxide-containing polyalkylene oxide block copolymers obtained by alkoxylation and their use as low-foaming pigment wetting agents in aqueous, optionally cosolvent-containing pigment pastes, aqueous and low-solvent lacquers and printing inks. As pigments, a large number of inorganic and organic pigments are mentioned. Particularly preferred are dispersing additives for producing aqueous (gas) carbon black pastes. In particular, a black paste is described which contains carbon black (Raven® 1170) in addition to the aforementioned polyalkylene oxides. However, no graphene materials are disclosed.

[0011] Therefore, there remains a need for a dispersant for graphene materials having at least one advantage over the prior art. In particular, such a dispersant is desirable to enable a stable dispersion of low viscosity while allowing high loading levels of graphene materials. Furthermore, the dispersant is desirable to enable the dispersion of graphene materials in polar and non-polar continuous phases, preferably liquid phases, where the continuous phase, preferably liquid phase, is in particular a solvent composition, a monomer composition, an oligomer composition or a polymer composition.

[0012] It has now surprisingly been found that this problem is solved by the use of a polyalkylene oxide having at least one aromatic group as a dispersing agent for graphene materials.

[0013] A first subject of the present invention is therefore the use of a polyalkylene oxide carrying at least one aromatic group as a dispersing agent for graphene materials.

[0014] A further subject of the invention is a method for dispersing graphene material, characterized in that the polyalkylene oxide used according to the invention is used as dispersing agent.

[0015] Another subject of the invention is a method for producing a composition comprising: (a) a continuous phase; (b) a dispersant suitable for use according to the invention; (c) Graphene material and A composition comprising or consisting of:

[0016] Yet another subject of the invention is a method for producing a composition comprising: (i) a dispersant suitable for use according to the invention; (j) Graphene materials and A composition comprising or consisting of:

[0017] Advantageous configurations of the subject matter of the present invention can be obtained from the claims, the examples and the detailed description of the invention. Moreover, it is expressly pointed out that the disclosure of the subject matter of the present invention includes all combinations of the individual features of the detailed description of the invention and the claims. In particular, the embodiment of one subject matter according to the present invention also applies mutatis mutandis to the embodiment of other subject matter according to the present invention.

[0018] The present inventors have determined that the use of a polyalkylene oxide having at least one aromatic group as a dispersing agent for graphene materials has many advantages.

[0019] One advantage of the present invention is the improved dispersibility of graphene materials in polar and non-polar continuous phases, advantageously liquid phases, in particular selected from the group consisting of solvent compositions, monomer compositions, oligomer compositions and polymer compositions. In contrast, dispersants for graphene materials known from the prior art are compatible with only a very small number of continuous phases and tend to cause segregation or inefficient dispersion even at very high dispersant concentrations.

[0020] Another advantage of the present invention is that dispersions with high loading levels of graphene material can be obtained, which allows achieving or enhancing electrical and thermal conductivity in the dispersion.

[0021] A further advantage of the present invention is the improved handling and metering properties in formulations, especially compared to graphene powder.

[0022] Similarly, one advantage of the present invention is that it is safer to handle, especially compared to powdered graphene material.

[0023] Yet another advantage of the present invention is that the viscosity of the composition containing the graphene material can be tailored, since the viscosity usually increases significantly during the dispersion of the graphene material, which can lead to solidification of the composition and, as a result, the composition can no longer be used. On the other hand, a very low viscosity does not allow the targeted shear effect to occur during dispersion, which leads to an inefficient dispersion process and an insufficient dispersion of the graphene material. In contrast, the polyalkylene oxide used according to the present invention acts as a viscosity modifier, allowing the targeted adjustment of the viscosity, thereby allowing effective dispersion at low and high viscosities, and thus allowing stable and highly loaded dispersions of the graphene material to be obtained.

[0024] A further advantage of the present invention is that the polyalkylene oxides used according to the present invention do not adversely affect the inherent properties of the graphene material, making the incorporation of the dispersions into thermoplastic, thermosetting or elastomeric polymer systems of adhesives and sealants significantly easier or even possible.

[0025] The subject matter according to the invention and its preferred embodiments are described below by way of example, without the intention of limiting the invention to these exemplary embodiments. When ranges, general formulae or compound classes are specified below, these are intended to include not only the corresponding ranges or compound groups explicitly mentioned, but also all subranges and subcompound groups that can be obtained by selecting individual values ​​(ranges) or compounds. Any embodiments that can be obtained by combining ranges / subranges and / or groups / subgroups fall completely within the disclosure of the present invention and are considered to be explicitly, directly and unambiguously disclosed.

[0026] Where average values ​​are given below, these are numerical averages, unless otherwise stated. Where measured values ​​or material properties are given below, these are measured values ​​or material properties measured at 25° C., preferably at a pressure of 101325 Pa (normal pressure), unless otherwise stated. Room temperature (RT) means a temperature of 25° C.

[0027] Where numerical ranges of the form "from X to Y" or "X~Y" are given below, X and Y represent the limits of the numerical range, which is equivalent to saying "at least from X to Y, inclusive," unless otherwise indicated. Thus, range data includes the range limits X and Y, unless otherwise indicated.

[0028] When a molecule or molecular fragment has one or more stereocenters or can be distinguished into isomers by reason of symmetry or other effects, such as restricted rotation, all possible isomers are included in the present invention.

[0029] The term "poly" includes compounds composed of at least two monomeric units.

[0030] "C" for a compound or group x ~C y The phrase "C1-C" refers to a compound or group having x to y carbon atoms. 20 The term "organyl group" refers to an organyl group, i.e., an organic group, having 1 to 20 carbon atoms. Similarly, the term "C1-C8 acyl group" refers to an acyl group having 1 to 8 carbon atoms. Similarly, the term "C1-C8 alkyl group" refers to an alkyl group having 1 to 8 carbon atoms. Similarly, the term "C6-C 13 The term "hydrocarbon radical" refers to a hydrocarbon radical having 6 to 13 carbon atoms.

[0031] The following formulae represent compounds or structural units that may be composed of repeat units, such as repeat fragments, repeat blocks or repeat monomer units, and may have a molar mass distribution. The frequency of these repeat units is indicated by the subscripts. The corresponding subscripts are the numerical average (number average) of all repeat units, unless otherwise stated. The subscripts of these units used in the formulae should therefore be considered as statistical averages (numerical averages), unless otherwise stated. The subscript values ​​used and the range of subscript values ​​stated are therefore understood to be the average values ​​of the possible statistical distributions of the structures and / or their mixtures that actually exist, unless otherwise stated. The repeat units in the following formulae can have any distribution. The structures composed of repeat units may be organized in blocks, with any number of blocks and any sequence, or may follow a randomized distribution, or may be organized alternately, or may form a gradient along the chain, if a chain is present, or in particular any mixed form in which groups with any different distributions may follow each other. In certain embodiments, the statistical distribution may be limited by the embodiment. For all ranges not affected by the limits, the statistical distribution remains unchanged.

[0032] A first subject of the present invention is the use of a polyalkylene oxide carrying at least one aromatic group as a dispersing agent for graphene materials.

[0033] Here, the plural form "polyalkylene oxides" denotes one or more, advantageously several, polyalkylene oxides.

[0034] The singular form "graphene material" denotes one or more, advantageously one, graphene material.

[0035] Thus, "use of a polyalkylene oxide having at least one aromatic group as a dispersant for graphene materials" is synonymous with "use of one or more polyalkylene oxides having at least one aromatic group as a dispersant for one or more graphene materials."

[0036] Therefore, "use of a polyalkylene oxide having at least one aromatic group as a dispersant for graphene materials" is also synonymous with "use of at least one polyalkylene oxide having at least one aromatic group as a dispersant for at least one graphene material."

[0037] The polyalkylene oxides are therefore also referred to below as dispersants. The dispersant therefore consists of the polyalkylene oxides that can be used according to the invention.

[0038] In order to achieve the objectives of the present invention, the polyalkylene oxide usable according to the present invention must have at least one aromatic group. Without being bound to a particular theory, it is assumed that the aromatic group improves the interaction of the polyalkylene oxide with the graphene material.

[0039] It is preferred that at least one aromatic group is a phenyl group.

[0040] To achieve optimum effectiveness it is further preferred that the weight percentage of total aromatic groups relative to the total weight of the dispersant is from 2% to 40%, advantageously from 5% to 25%, especially from 7% to 15%.

[0041] The polyalkylene oxide is represented by the formula (A): [ka] where the group R A , R B , R C and R D are each, independently of one another, an organic group or hydrogen (H), where the organic group may each, independently of one another, be linear or branched or cyclic, saturated or unsaturated, aliphatic or aromatic, substituted or unsubstituted, or combinations thereof, where possible (e.g., alicyclic), provided that the group R A , R B , RC and R D At least one unit in which at least one of the groups R is an aromatic group is included. The organic group is preferably a hydrocarbon group containing no heteroatoms, in particular a C1-C8 hydrocarbon group containing no heteroatoms. The polyalkylene oxide is preferably a polyalkylene oxide having four groups R A , R B , R C and R D It is preferred that the polyalkylene oxide comprises units in which exactly one of the groups is a phenyl group and the other three groups are hydrogen (H). It is therefore preferred that the polyalkylene oxide has at least one unit of the formula -O-CH2-CHPh- or -CH2-CHPh-O-, where Ph represents a phenyl group.

[0042] The polyalkylene oxide is represented by the general formula (B) R 1 [O(SO) a (PO) b (BO) c (EO) d R 2 ] n (B) It is further preferred that the compound is selected from the group consisting of: R 1 are each independently n-valent C1 to C 20 is selected from the group of organyl groups, R 2 are each independently selected from the group consisting of a C1-C8 acyl group, a C1-C8 alkyl group, and hydrogen; SO = styrene oxide; PO=propylene oxide; BO=butylene oxide; EO = ethylene oxide; n=1 to 6, advantageously 1 to 4, in particular 1 to 3, a=1 to 10, advantageously 1 to 5, in particular 1 to 3, b=0 to 50, preferably 0 to 20, in particular 0 to 15, c=0 to 10, advantageously 0 to 5, in particular 0 to 3, d=0-50, advantageously 0-20, in particular 0-15.

[0043] In formula (B), it is preferable that a+b+c+d≧3.

[0044] For example, the polyalkylene oxide may be represented by the general formula (C): R 1 O(SO) a (PO) b (BO) c (EO) d R 2 (C) Preferably, the compound is selected from the group consisting of R 1 are each independently a monovalent C6-C 13 is selected from the group of hydrocarbon groups, R 2 are each independently selected from the group consisting of a C1-C8 acyl group, a C1-C8 alkyl group, and hydrogen; SO = styrene oxide; PO=propylene oxide; BO=butylene oxide; EO = ethylene oxide; a=1~1.9, b=0 to 3; c=0 to 3, d=3~50, However, d≧a+b+c.

[0045] In formula (C), it is preferable that a+b+c+d≧3.

[0046] The polyalkylene oxide is represented by the general formula (D) R 1 [O(SO) a (PO) b (BO) c (EO) d R 2 ] n (D) It is further preferred that the compound is selected from the group consisting of: R1 are each independently n-valent C1 to C 20 is selected from the group of organyl groups, R 2 are each independently selected from the group consisting of a C1-C8 acyl group, a C1-C8 alkyl group, and hydrogen; SO = styrene oxide; PO=propylene oxide; BO=butylene oxide; EO = ethylene oxide; n=1 to 6, advantageously 1 to 4, in particular 1 to 3, a=1 to 10, advantageously 1 to 5, in particular 1 to 3, b=0 to 50, preferably 3 to 20, in particular 3 to 15, c=0, d=0.

[0047] In formula (B) or (C) or (D), it is preferred that a+b+c+d≧3, advantageously ≧4 and in particular ≧5.

[0048] In formula (B) or (C) or (D), SO (styrene oxide) is a compound having four groups R A , R B , R C and R D is a phenyl group and the other three groups are hydrogen (H).

[0049] In formula (B) or (C) or (D), EO (ethylene oxide) is a group having four R A , R B , R C and R D represents a unit of formula (A) in which all are hydrogen (H).

[0050] In formula (B) or (C) or (D), PO (propylene oxide) is a compound having four groups R A , R B , R C and R Dwhere exactly one of the groups is a methyl group and the other three groups are hydrogen (H).

[0051] In formula (B) or (C) or (D), BO (butylene oxide) is a compound having four groups R A , R B , R C and R D Exactly one of the groups is an ethyl group and the other three groups are hydrogen (H), or there are four groups R A , R B , R C and R D where exactly two of the groups are methyl groups and the other two groups are hydrogen (H).

[0052] Those skilled in the art know that compounds of formula (B) or (C) or (D) usually exist as a mixture. The hydrophobic / hydrophilic balance can be controlled by the various alkylene oxide monomers and their ratio to the whole polymer, and in particular, the dispersant can be tailored to the graphene material and the continuous phase. Here, the EO units exhibit hydrophilic behavior, and the PO, BO and SO units exhibit hydrophobic behavior.

[0053] The arrangement of the alkylene oxide units can be, for example, statistical or block-like. Particularly preferably, the alkylene oxide units are arranged in blocks. The polyalkylene oxide is therefore advantageously a block copolymer. The polyalkylene oxide is therefore advantageously a polyalkylene oxide block copolymer. It is therefore preferred that the polyalkylene oxide is a styrene oxide-based polyalkylene oxide block copolymer. Here, it is preferred that the hydrophobic units, such as SO, PO or BO, and the hydrophilic EO units form separate blocks. It is preferred that the hydrophilic EO units are of the formula R 2 Preferably, R is bonded to the 2 is advantageously hydrogen (H). The hydrophobic units SO, PO and BO are advantageously in combination with the EO block and R1 exists between them. Therefore, the radical R 1 , SO, PO and BO units, and the oxygen atoms bonding R 1 to the alkylene oxide units form a continuous portion in the polyalkylene oxide, to which the EO units terminated with R 2 are preferably bonded. Therefore, in one case, it is preferable that d ≧ a + b + c in formula (B) or (C) or (D), and in other cases, it may be preferable that d < a + b + c in formula (B) or (C) or (D). In the first case, the polyalkylene oxide is more hydrophobic, and in the second case, they are more hydrophilic.

[0054] R 1 can further contain heteroatoms selected, for example, from N and O, especially N, in addition to carbon atoms and hydrogen atoms. However, it is preferable that R 1 does not contain SO units, PO units, BO units and EO units. Preferably, R 1 does not contain heteroatoms. Advantageously, R 1 are each independently selected from the group of monovalent C6-C 13 hydrocarbon groups. Advantageously, R 1 are each independently linear (i.e., unbranched), or branched or cyclic, saturated or unsaturated, aliphatic or aromatic, or a combination thereof if possible. More preferably, R 1 are each independently linear or branched saturated aliphatic groups. Even more preferably, R 1 are linear or branched or alicyclic groups having 6 to 13 carbon atoms. Even more preferably, R 1 are linear aliphatic groups especially selected from the group consisting of n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl and n-dodecyl. Suitable compounds of formula (B) or (C) or (D) and their synthesis are described in European Patent Application Publication No. 1078946 and are commercially available, for example, under the name TEGOMER® DA 646.

[0055] base R 1 is the corresponding hydroxy-functional compound R 1 (OH) n where n is as defined in formula (B) or (D). 1 (OH) n Examples of suitable hydroxy-functional compounds R are given in the Examples (see Table 1). 1 (OH) n can be selected from the group of sugars and sugar alcohols, such as glucose, gulose and sorbitol. Furthermore, the hydroxy-functional compound R 1 (OH) n It is also possible to use polyglycerol as the binder.

[0056] R 2 It is preferred that R does not contain SO, PO, BO and EO units. 2 is advantageously hydrogen (H).

[0057] The number average molecular weight (M n ) is preferably 400 g / mol to 4000 g / mol, advantageously 500 g / mol to 2500 g / mol, in particular 600 g / mol to 1500 g / mol. n ) is advantageously determined by gel permeation chromatography (GPC).

[0058] Besides oxygen atoms, the polyalkylene oxide may contain further heteroatoms, such as nitrogen atoms. However, it is preferred here that the polyalkylene oxide does not contain phosphorus atoms. It is even more preferred here that the polyalkylene oxide does not contain sulfur atoms. It is therefore also preferred that the polyalkylene oxide does not contain other heteroatoms other than oxygen atoms and optionally nitrogen atoms. Therefore, preferably, the polyalkylene oxide is composed only of carbon atoms, hydrogen atoms, oxygen atoms and optionally nitrogen atoms. Therefore, preferably, the polyalkylene oxide is composed of carbon atoms, hydrogen atoms, oxygen atoms and optionally nitrogen atoms. It is particularly preferred that the polyalkylene oxide is not composed of other heteroatoms other than oxygen atoms. Therefore, particularly preferably, the polyalkylene oxide is composed only of carbon atoms, hydrogen atoms and oxygen atoms. Therefore, particularly preferably, the polyalkylene oxide is composed of carbon atoms, hydrogen atoms and oxygen atoms.

[0059] It is further preferred that the graphene material is a graphene material according to ISO-TS 80004-13, which is advantageously selected from the group consisting of monolayer graphene, bilayer graphene, trilayer graphene, few layer graphene, multilayer graphene, 1-10 layer graphene, epitaxial graphene, exfoliated graphene, graphene nanoribbons, graphene nanoplates, graphene nanoplatelets, graphene nanosheets, graphene microsheets, graphene nanoflakes, graphene quantum dots, graphene oxide, graphene oxide nanosheets, multilayer graphene oxide and reduced graphene oxide, and mixtures thereof, with graphene materials having in particular 1-10 graphene layers being preferred.

[0060] It is preferred that the graphene material has a carbon proportion (weight proportion of carbon relative to the total weight of the graphene material) of at least 80%, advantageously at least 90%, in particular at least 95%.

[0061] The graphene material is preferably a single-layer or multi-layer graphene material, i.e. a graphene material comprising one or more graphene layers. As multi-layer graphene material, a graphene material having 2 to 10 graphene layers is preferably used.

[0062] It is preferred that the graphene material has a thickness of less than 10 nm, advantageously less than 5 nm, in particular less than 3 nm.

[0063] The graphene material is 0.01 g / cm 3 ~0.10g / cm 3 , advantageously 0.01 g / cm 3 ~0.08g / cm 3 , especially 0.01 g / cm 3 ~0.05g / cm 3 It is preferred that the powder has a bulk density of 0.1 to 1.0 μm.

[0064] Advantageously, the graphene material is present as granules, flakes, powders, films, sheets, platelets, nanoribbons and / or fibers.

[0065] Further details regarding graphene material, its production, properties and applications can also be found in the technical literature (Roempp 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 above polyalkylene oxides allow the graphene material to be dispersed in a liquid continuous phase. It is preferable to disperse the graphene material in a liquid continuous phase mainly composed of a compound selected from the group consisting of polyethers, particularly polyether polyols, polyesters, particularly polyester polyols, polycarbonates, particularly polycarbonate polyols, polybutadienes, particularly polybutadiene polyols, epoxy resins, polysiloxanes, silicone oils, vegetable oils, mineral oils, organic synthetic oils, silyl-modified polymers, silyl-modified reactive diluents, (meth)acrylic acid, (meth)acrylates, cyanoacrylates, dihydrolevoglucosenone (Cyrene®), dimethylformamide (DMF), organic carbonates, acetone, glycols, dimethylsulfoxide (DMSO), tetrahydrofuran (THF), methyl ethyl ketone (MEK), acetates, N-methyl-2-pyrrolidone (NMP), alcohols and dibasic acid esters (DBE).

[0067] Advantageously, the 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 silyl-modified polymer advantageously carries triethoxysilyl and / or trimethoxysilyl groups. It is preferred that the polymer backbone is a polysiloxane backbone (silicone backbone), a polybutadiene backbone or a polyether backbone.

[0069] The term "(meth)acrylic acid" refers to methacrylic acid and / or acrylic acid. The term "(meth)acrylate" refers to methacrylic acid esters and / or acrylic acid esters. The (meth)acrylates are advantageously 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] The organic carbonate is advantageously selected from the group consisting of dimethyl carbonate, propylene carbonate, allyl ethyl carbonate, vinylene carbonate, methyl ethyl carbonate, ethylene carbonate, fluoroethylene carbonate, butylene carbonate, diethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl isopropyl carbonate, dipropyl carbonate, dibutyl carbonate and chloroethylene carbonate.

[0071] The glycol is advantageously 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 acetate is advantageously selected from the group consisting of methyl acetate, ethyl acetate, n-propyl acetate and n-butyl acetate.

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

[0074] The dibasic ester (DBE) is advantageously selected from the group consisting of dimethyl succinate (DBE-4), dimethyl glutarate (DBE-5) and dimethyl adipate (DBE-6), where mixtures are usually used, for example DBE-9, which is a mixture of DBE-4 and DBE-5.

[0075] It is further preferred that the continuous phase comprises a major proportion of a plasticizer selected from the group consisting of phthalates, citrates and adipates.

[0076] It is further preferred that the continuous phase comprises as a main component a baking lacquer, for example a silicone-based baking lacquer.

[0077] It is further preferred that the continuous phase comprises a major component of an unsaturated polyester resin (UPES) or a vinyl ester resin.

[0078] It is further preferred that the continuous phase comprises a phenolic resin (UF, MUF) or an amino resin as a main component.

[0079] The main component of the continuous phase is understood to mean the main component of the continuous phase with respect to its weight proportion, which is preferably at least 50%, advantageously at least 90% and in particular 100% based on the total weight of the continuous phase, with the upper limit being 100%.

[0080] A further subject of the invention is a method for dispersing graphene material, characterized in that the polyalkylene oxide used according to the invention is used as dispersing agent.

[0081] The method comprises the following indirectly or directly successive, advantageously directly successive, process steps: a) the process steps of charging the continuous phase; b) a process step of adding a dispersant corresponding to the use according to the invention, c) A process step of adding and dispersing the graphene material It is preferred that the compound contains

[0082] The method also comprises the following indirectly or directly successive, advantageously directly successive, process steps: i) a process step of charging a dispersant corresponding to the use according to the invention, j) Process step of adding and dispersing graphene material It is preferred that the compound contains

[0083] Here, the term "dispersant" is understood to mean the polyalkylene oxides defined above. The dispersant therefore consists of one or more polyalkylene oxides that can be used according to the invention.

[0084] Here, the dispersion is advantageously carried out under shear. This achieves a high energy input. This leads to the breakage and exfoliation of agglomerates and the creation of new unsaturated surfaces. These attack points, i.e. functional groups such as hydroxy, carboxy, aldehyde, keto, epoxy and amino groups, as well as conjugated systems, are suitable for the attachment of various dispersing and stabilizing agents. This in situ addition makes the dispersion very effective, resulting in higher loading levels and more stable dispersions. Higher loading levels allow for wider clearances in the formulation for end uses such as adhesives, sealants and thermal interface materials.

[0085] In the process according to the invention, in particular in step c) or j), various dispersion techniques and devices can be used, such as bead mills, dissolvers (e.g. DISPERMAT® dissolvers), three-roll mills, Ultra-Turrax, wet jet mills, Conchier devices, high-shear mixers, preferably devices selected from the group consisting of high-speed mixers, high-speed mixers and thermomixers. Dispersion can also be carried out by ultrasonication. Particularly preferably, dispersion is carried out using dissolvers (e.g. DISPERMAT® dissolvers) or bead mills.

[0086] Here, it is preferred that the power or energy is introduced or applied for 0.1 minutes to 99 hours, preferably 0.1 minutes to 2 hours, and particularly preferably 1 minute to 15 minutes.

[0087] The method according to the invention has the advantage that it is very easy to carry out and therefore makes it possible to produce compositions with a high weight proportion of graphene material.

[0088] Yet another subject of the invention is a method for producing a composition comprising: (a) a continuous phase; (b) a dispersant suitable for use according to the invention; (c) Graphene material and A composition comprising or consisting of:

[0089] Here, dispersant is understood to mean in this case also at least one polyalkylene oxide as defined above. The dispersant therefore consists of one or more polyalkylene oxides that can be used according to the invention.

[0090] The weight proportion of component (c) relative to the weight of the composition is preferably 0.1% to 90%, advantageously 5% to 60%, and in particular 25% to 40%. Thus, the weight of component (c) divided by the weight of the composition is 0.1% to 90%, advantageously 5% to 60%, and in particular 25% to 40%.

[0091] The weight ratio of component (b) to the weight of component (c) is preferably 0.01% to 200%, advantageously 30% to 150%, and particularly preferably 50% to 100%. Thus, the weight of component (b) divided by the weight of component (c) is 0.01% to 200%, advantageously 30% to 150%, and particularly preferably 50% to 100%.

[0092] Yet another subject of the invention is a method for producing a composition comprising: (i) a dispersant suitable for use according to the invention; (j) Graphene materials and A composition comprising or consisting of:

[0093] Here, dispersant is understood to mean in this case also at least one polyalkylene oxide as defined above. The dispersant therefore consists of one or more polyalkylene oxides that can be used according to the invention.

[0094] The weight proportion of component (j) relative to the weight of the composition is preferably 0.1% to 90%, advantageously 5% to 60%, and in particular 25% to 40%. Thus, the weight of component (j) divided by the weight of the composition is 0.1% to 90%, advantageously 5% to 60%, and in particular 25% to 40%.

[0095] The weight ratio of component (i) to the weight of component (j) is preferably 0.01% to 200%, advantageously 30% to 150%, and particularly preferably 50% to 100%. Thus, the weight of component (i) divided by the weight of component (j) is 0.01% to 200%, advantageously 30% to 150%, and particularly preferably 50% to 100%.

[0096] The composition according to the invention may still comprise further additives, for example fillers for improving electrical conductivity, advantageously selected from the group consisting of poly-3,4-ethylenedioxythiophene (PEDOT), polyaniline, carbon nanotubes, carbon black, carbon fibres, metal particles, metal fibres, silver nanowires, graphite (e.g. expanded graphite) and manganese oxide; fillers for improving thermal conductivity, advantageously selected from the group consisting of hBN, AlN, Al2O3, SiO2, ZnO, MgO, SiC, nanodiamonds; flame retardants; impact modifiers; colour pigments; UV stabilizers; viscosity modifiers; flow aids; antifoaming agents; ionic liquids; wetting agents; and / or scratch protection agents.

[0097] The combination of components (a), (b) and (c) results in stable, advantageously low viscosity dispersions, even at high loading levels of (c).

[0098] Similarly, the combination of components (i) and (j) also results in stable, advantageously low viscosity dispersions at high loading levels of (j).

[0099] The compositions according to the invention, especially in the form of a paste, can be universally used, for example in the automotive sector, heat exchangers, electronic applications, thermal management, antistatic, the semiconductor industry, housings, sealing, 3D printing, injection molded parts, tube systems, membranes, fuel cells, cable systems, electromagnetic shielding (EMV), thermal management of battery systems, adhesives and sealants, and potting compounds.

[0100] The compositions according to the invention, especially in the form of a paste, are furthermore suitable as additives for the following materials: elastomers, thermosets, thermoplastics, thermoplastic elastomers.

[0101] The composition according to the invention, especially in the form of a paste, is particularly suitable as an additive for the following materials / applications: - adhesives and sealants (especially electrically and / or thermally conductive), including epoxy resins, phenolic resins, polyurethanes, silane-modified polymers (silyl-modified polymers, SMPs), acrylates, reactive hot melts; - Silicone (RTV, HTV, LSR, HCR), - acrylates, Polyurethanes, for example thermoplastic polyurethanes, rubber, preferably SBR, BR, natural rubber, polybutadiene, functionalized polybutadiene; thermosetting resins, preferably polyurethanes, polyester resins, phenolic resins, epoxy resins, acrylate resins, silicone resins, - Thermal Interface Materials: gap fillers, tapes, greases, phase change materials, potting, packaging, underfills, castings, coatings, protective coatings, - standard thermoplastics, advantageously selected from PE, PP, PS, PVC, α-olefins, butadiene derivatives, Vestenamer® (Evonik), in technical thermoplastics, preferably PET, PMMA, PC, POM, PA, PBT, PEBA, TPU, PU, ​​TPE, in high performance thermoplastics, preferably PPS, PEEK, PES, PI, PEI, copolymers, - semi-finished products, - In the automotive sector: electric drives, thermal management of battery systems, on-board and off-board charging infrastructure, electronics and power electronics, fuel cells, sensors, displays, cockpits, interactive surfaces, EMV shielding (electromagnetic shielding), - Electronics and power electronics (connections), - Connection and heat dissipation of microchips, electronic components, displays and indicators, - LED headlights / spotlights, LED, surface lighting connection and heat dissipation, - Communication system connection and heat dissipation, - Hydrogen technology and gas systems where anti-static and gas-tightness are required (seals, fuel cells, tanks, connectors, plugs, tubes / cables), - Mineral oils, silicone oils, process oils, vegetable oils, modified vegetable oils, motor oils, hydraulic oils, driveline oils, greases, gels, phase change materials for electrical conductivity, thermal conductivity and reducing sliding friction.

[0102] In the above applications / materials, the composition advantageously provides at least one of the following effects: - (Improvement of) electrical conductivity, - (Improvement of) thermal conductivity, - Reduced friction, - Improved mechanics, - Improved scratch resistance, - Colours / pigments, - Absorption of radiation (ultraviolet rays), - Antibacterial / antiviral effects, - Improved flame retardancy, - Reduced gas permeability.

[0103] Working Example The following examples are presented merely to illustrate embodiments of the present invention to one of ordinary skill in the art and are not intended to limit the claimed subject matter in any way.

[0104] Dispersants (dispersion additives, or simply "additives") The following polyalkylene oxides are prepared as dispersants according to the invention, corresponding to the stoichiometry shown in Table 1, where the numbers indicate the molar ratio of alkylene oxide (SO, PO, BO, EO) to the starting alcohol. Thus, additive 4 is based on 1 mol SO, 2 mol BO, 8 mol PO and 0 mol EO, respectively, to 1 mol hexan-1-ol. The synthesis of the starting alcohols and the corresponding alkylene oxides is carried out as described in EP 1 078 946 A1. The groups R of the additives in Table 1 are 1 are derived from the starting alcohol used (e.g., hexane-1-ol gives R 1 = hexyl). The following applies to all additives in Table 1: 2 =H.

[0105] [Table 1]

[0106] Here, dispersants usable according to the invention are additives 1 to 16, which have aromatic groups. Dispersants that cannot be used according to the invention are additives 17 and 18, as well as Solsperse® 39000 (Lubrizol) and TEGOMER® DA 100 N (Evonik), which do not have aromatic groups.

[0107] Filler Graphene: As the graphene material, graphene with the following properties was used: Dv50=20 μm (measured by laser diffraction method), surface resistance ≦10 Ω / sq. (four samples on a 25 μm film from a filter membrane), tap density 3 =0.251gcm -3 (According to ASTM D7481).

[0108] Carbon Black: Carbon black is used as a filler that cannot be used according to the invention, which can be used to improve electrical conductivity. This carbon black has a DBP absorption (DBP=dibutyl phthalate) of 119 ml / 100 g as determined according to ASTM D2414 and a DBP absorption of 300 g / dm3 as determined according to ASTM D1513. 3 Bulk density of less than 250 ppm on a 325 mesh sieve, and a 135 mm diameter sieve thickness determined in accordance with ASTM D3765. 2 It is characterized by its CTAB surface area in g / g (CTAB = cetyltrimethylammonium bromide).

[0109] Making Pastes with DISPERMAT® Dissolvers Essentially, the paste is produced discontinuously (batchwise) using a suitable dispersing unit, a dissolver (DISPERMAT® dissolver CV4-Plus, VMA-GETZMANN). The paste is produced in a 250 mL stainless steel vessel using a dissolver disc with a diameter of 40 mm. Here, a batch size of 100 g paste is selected for the 250 mL stainless steel vessel. The stainless steel vessel is charged with a defined amount of continuous phase (for example polyether polyols, polyester polyols, methyl methacrylate, polybutadiene diols, etc.) depending on the experiment. If a dispersing additive is used, a defined amount of additive (additive to pigment = AoP [%]) relative to the amount of filler used is added to the continuous phase. "Pigment" or "filler" is understood to mean graphene material or carbon black. The weight of the continuous phase m konti.Phase , the total weight of the composition m gesamt , weight of filler m Fuellstoff , weight of additive mAdditiv , Maximum filling level Fuellgrad max and the weight of additive to the weight of filler amount AoP (additive to pigment) the following relationship holds:

number

[0110] The vessel with the continuous phase and the dispersing additive is clamped to the DISPERMAT® dissolver device and the stirring tool is lowered so that the dissolver disc is in the continuous phase but does not touch the bottom of the cup. The dispersing additive is introduced into the continuous phase by stirring at 750 rpm (rpm = revolutions per minute) for 1 minute to prevent it from settling to the bottom of the stainless steel vessel. The filler is then added very slowly and in small portions, with the stirrer set at 750 rpm to 1000 rpm depending on the dust generation. The addition is carried out in small portions over a period of about 5 minutes. After the addition is complete, the speed of the stirrer of the DISPERMAT® dissolver is increased to 2000 rpm to 2500 rpm to ensure an ideal dispersion. This condition is maintained for another 5 minutes until the graphene-based paste is completely dispersed.

[0111] Visual evaluation of paste storage stability Glass test vessels with a base diameter of 2.5 cm are filled with 40 g of paste and examined after 12 and 72 hours of storage at room temperature. Further samples are examined after 72 hours of storage at 50°C. Examination includes visual inspection by two people with the naked eye for syneresis and appearance of the paste. Also examined is the flow of the paste on a metal spatula. The following evaluation criteria "unstable" or "stable" are used: Unstable (Stability: None): The paste forms at least 2 mm of clear serum on the surface. The paste appears granular. The paste does not flow evenly from the spatula. Stable (Stability: Yes): The paste forms a clear serum less than 2 mm. The paste appears homogenous and creamy. The paste flows evenly from the spatula.

[0112] Viscosity - Rheological Testing of Pastes The viscosity of the paste is measured using a rheometer (Physica MCR 301 / Anton Paar). For the tests, a measuring shaft without transponder D-CP / PP7 (Anton Paar) is used, connected to a 25 mm disposable measuring plate (D-PP25 / AL / S07 D: 25 mm disposable measuring plate / Anton Paar). Before starting the measurement, a zero gap (here 0.5 mm) is set. With this gap width, the subsequent pastes are measured. The rheometer is now ready for the measurement. A defined amount of paste is applied to the rheometer plate and the pre-set measuring gap of 0.5 mm is adjusted. Afterwards, the excess paste at the edges is removed ("Trimming the sample"). Only then can the measurement be started. Shear rate 0.1 s -1 ~1000s -1 Run a linear ramp with the following conditions / parameters: [ka]

[0113] For graphical evaluation, the viscosity is plotted against the shear rate. The course of the curve for a paste with additive is then compared with that for a paste without additive. Shear rate 1s -1 and 10s -1 It is also common to compare only values ​​at

[0114] Hegman Grindometer Test [Table 2]

[0115] The Hegman Grindometer is used to measure the dispersion of particles or aggregates in a liquid continuous phase, but does not measure actual particle size or size distribution.

[0116] The grindometer is a flat steel block with two shallow wedge-shaped grooves cut into its surface. These grooves run uniformly from the maximum depth at one end of the grindometer to the zero point at the other end of the steel block. The depth of the wedge can be read off a scale cut into the side. The Hegman scale ranges from 0 to 8, with higher Hegman numbers (Hegman values) indicating smaller particles. Here, the following Hegman number and µm assignments apply: 0 Hegman = 100 μm 4 Hegman = 50 μm 8 Hegman = 0 μm

[0117] The cleaned and dried grindmeter is placed on a horizontal, non-slip surface. The grindmeter is filled with the test paste at the deepest point of the groove. The paste should now flow slightly over the edge of the groove. The scraper is placed parallel to the short side of the grindmeter at the deepest point of the groove and drawn quickly vertically towards the shallow end of the grindmeter groove. Immediately after levelling the sample, the grindmeter is observed at right angles to its long side and at an angle of 20° to 30° to the surface, while being held up to a light so that the surface structure of the paste in the groove is visible. The position where a relatively large number of particles or scratch marks of particles are first visible in the groove is identified and the scale value (Hegman scale) associated with it is read off.

[0118] Early failures in the grooves (high Hegman number) mean that the paste contains e.g. residual agglomerates or a poorer dispersion of the filler (i.e. graphene material or carbon black) in the continuous phase, and therefore a greater paste instability and the other drawbacks mentioned above of incomplete graphene dispersion in the final application can be expected.

[0119] The grindometer test is further rated as follows: [Table 3]

[0120] Graphene paste production The preparation of graphene paste according to the following examples is carried out as follows: 1. Place the continuous phase into a 250 ml metal cup. 2. Add the dispersion additive (100% AoP) and stir briefly with a spatula to prevent the additive from settling to the bottom. 3. Using a DISPERMAT® dissolver, introduce the additives into the continuous phase by stirring with a 40 mm dispersing disc at 750 rpm for approximately 1 minute. 4. Slowly add the filler in small amounts over a period of approximately 5 minutes at 750-1000 rpm. 5. After the filler addition is complete, mix for an additional 5 minutes at 2000-2500 rpm until the filler is completely dispersed.

[0121] Example 1: Paste based on polyether polyol For the preparation of pastes based on polyether polyols, Desmophen® 1110 BD (Covestro) is used as the continuous phase (see Tables 2 and 3): [Table 4]

[0122] [Table 5]

[0123] Example 2: Paste based on polyester polyol For the preparation of pastes based on polyester polyols, Dynacoll® 7250 (Evonik) is used as the continuous phase (see Tables 4 and 5): [Table 6]

[0124] [Table 7]

[0125] Example 3: Paste based on polybutadiene diol For the preparation of pastes based on polybutadiene diol, Polyvest® HT (Evonik) is used as the continuous phase (see Tables 6 and 7): [Table 8]

[0126] [Table 9]

[0127] Example 4: Epoxide-based paste For the preparation of epoxide-based pastes, Epikote® Resin 828 (Hexion) is used as the continuous phase (see Tables 8 and 9): [Table 10]

[0128] [Table 11]

[0129] Example 5: Methyl methacrylate based paste For the preparation of pastes based on methyl methacrylate, MERACRYL® MMA (Roehm) is used as the continuous phase (see Tables 10 and 11): [Table 12]

[0130] [Table 13]

[0131] Example 6: Vegetable oil based paste For the preparation of vegetable oil based pastes, castor oil is used as the continuous phase (see Tables 12 and 13): [Table 14]

[0132] [Table 15]

[0133] Example 7: Paste based on silyl-modified polymer (SMP) For the preparation of pastes based on silyl-modified polymers (SMPs), TEGOPAC® RDS 1 is used as the continuous phase (see Tables 14 and 15): [Table 16]

[0134] [Table 17]

[0135] Only the combination of polyalkylene oxide and graphene material usable according to the invention (irrespective of the continuous phase) results in compositions with high stability, low viscosity, and good results in the Hegman Grindometer test.

Claims

1. Use of a polyalkylene oxide having at least one aromatic group as a dispersant for a graphene material.

2. The use according to claim 1, wherein the at least one aromatic group is a phenyl group.

3. The use according to claim 1 or 2, wherein the weight ratio of all aromatic groups to the total weight of the dispersant is 2% to 40%.

4. wherein the polyalkylene oxide has at least one unit of the formula -O-CH ２ -CHPh- or of the formula -CH ２ -CHPh-O-, where Ph represents a phenyl group, Use according to claim 1.

5. The polyalkylene oxide is selected from compounds of the general formula (B) R １ [O(SO) ａ (PO) ｂ (BO) ｃ (EO) ｄ R ２ ｎ (B)​ where R １ is, independently of each other, selected from the group of n-valent C １ to C ２０ organic groups, R ２ is, independently of one another, selected from the group consisting of C １ to C ８ acyl group, C １ to C ８ alkyl group and hydrogen, SO = styrene oxide, PO = propylene oxide, BO = butylene oxide, EO = ethylene oxide, n = 1 to 6, a = 1 to 10, b = 0 to 500 to 15, c = 0 to 100 to 3, d = 0 to 50, the use according to claim 1.

6. The use according to claim 1, wherein the polyalkylene oxide does not contain heteroatoms other than oxygen atoms and optionally nitrogen atoms.

7. The use according to claim 1, wherein the graphene material is a graphene material compliant with ISO-TS 80004-13.

8. Dispersing the graphene material in a liquid continuous phase mainly containing a compound selected from the group consisting of polyethers, polyesters, polycarbonates, polybutadienes, epoxy resins, polysiloxanes, vegetable oils, mineral oils, synthetic organic oils, silyl-modified polymers, silyl-modified reactive diluents, (meth)acrylates, cyanoacrylates, dihydrolevoglucosenone (Cylene®), dimethylformamide (DMF), organic carbonates, acetone, glycols, dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), acetates, N-methyl-2-pyrrolidone (NMP), alcohols and dibasic acid esters (DBE), the use according to claim 1.

9. A method for dispersing a graphene material, characterized in that a polyalkylene oxide is used as a dispersant and the provisions according to claim 1 apply.

10. The following indirectly or directly continuous process steps: a) A process step of charging a continuous phase, b) A process step of adding a dispersant according to the provisions of claim 1, c) A process step of adding and dispersing a graphene material The method according to claim 9, comprising.

11. The following indirectly or directly continuous process steps: i) A process step of loading a dispersant according to the provisions recited in claim 1 j) A process step of adding and dispersing a graphene material The method according to claim 9, comprising: **Claim 12** A composition, comprising: (a) A continuous phase, (b) A dispersant according to the provisions recited in claim 1, (c) A graphene material The composition comprising or consisting of the foregoing. **Claim 13** A composition, comprising: (i) A dispersant according to the provisions recited in claim 1, (j) A graphene material The composition comprising or consisting of the foregoing. **Claim 14** The composition according to claim 12 or 13, wherein the weight ratio of the component (c) or (j) to the weight of the composition is 0.1% to 90%. **Claim 15** The composition according to claim 12 or 13, wherein the weight ratio of the component (b) or (i) to the weight of the component (c) or (j) is 0.01% to 200%.