PTFE reduced structures for powder coating

Abstract

The present invention relates to PTFE-reduced or PTFE-free compositions that can be added to powder coating formulations to improve the roughness / structuring of powder coatings. The invention also relates to a method for preparing such a composition. The invention further relates to a PTFE-reduced or PTFE-free powder coating having improved structural properties, and to a method for producing such a powder coating.

Description

Technical Field

[0001] The present invention relates to PTFE-reducing additives for powder coatings to produce powder coatings having a structured surface. Background Art

[0002] Powder coatings are used for solvent-free metal coatings (35%), household appliances (21%), facades (20%), furniture (13%) and motor vehicles. In many applications, structured coatings are desired. This is achieved by adding polytetrafluoroethylene ("PTFE") or modifying individual components with PTFE.

[0003] In addition, additives for modifying the surface and properties of powder coatings are known. Therefore, individual components of the composition according to the invention have been described as additives for powder coatings. However, these components are not used as structuring agents without PTFE, but rather modify other properties of the powder coating.

[0004] Document CN112724799A discloses a powder coating comprising a modified polyethylene wax in a structuring additive that should give the powder coating a sandy surface and unmodified bentonite. Bentonite is added to the powder coating to adjust the gloss. The type of modification of the polyethylene wax is not disclosed.

[0005] CN103160192 discloses a powder coating comprising a PTFE-modified polyethylene wax in micronized form, a micronized organophilic modified bentonite and a variety of other components. Therefore, the inventors believe that PTFE modification is necessary for the structural properties. Modification of the polyethylene wax with α,β-unsaturated carboxylic acids and / or their derivatives is not considered.

[0006] JP 4818822 B2 discloses thixotropic agents consisting of oxidized polyethylene wax and bentonite, and coatings containing these thixotropic agents.

[0007] Fluorinated compounds are persistent substances (POPs, EU Regulation 2019 / 1021) that are increasingly criticized and regulated. These can be produced as by-products in the production or further processing of PTFE. Therefore, there is a need for PTFE-poor or PTFE-free alternatives for structuring powder coating surfaces. It is also advantageous when different strengths of structuring effects can be adjusted with structuring additives. Summary of the invention

[0008] Surprisingly, it has now been found that the surface of powder coatings can be significantly structured without the addition of PTFE when a mixture of a wax modified with an α,β-unsaturated carboxylic acid and a modified bentonite is added to the coating before baking.

[0009] As a measure of the structuring of the powder coating surface, the roughness value (Rz) can be determined, which gives the average roughness of the surface in accordance with EN ISO 4287: 1997. The higher the value of the roughness value, the more strongly the surface is structured.

[0010] Therefore, a subject of the present invention is a composition (C) comprising as an essential component

[0011] (a) at least one wax (mW) modified by grafting α,β-unsaturated carboxylic acids and / or derivatives thereof; and

[0012] (b) modified layered silicates (mP), preferably organophilically modified layered silicates (omP),

[0013] The composition ensures structuring of the surface of the powder coating without the need to add a PTFE-containing structuring agent.

[0014] The use of composition (C) for the structuring of powder coatings is therefore also a subject of the present invention.

[0015] Another subject of the present invention is a process for preparing the composition (C) according to the invention, wherein the modified and optionally micronized phyllosilicate (mP), the wax (mW) modified by grafting α,β-unsaturated carboxylic acids and / or derivatives thereof and optionally micronized and optionally further components are mixed and optionally micronized by hot mixing, extrusion, grinding or vibration.

[0016] The present invention also provides a powder coating composition (PC) comprising

[0017] a) at least one thermoplastic or, after baking, thermosetting polymer,

[0018] b) at least one wax (mW) modified by grafting α,β-unsaturated carboxylic acids and / or derivatives thereof; and

[0019] c) at least one modified layered silicate (mP),

[0020] And a process for preparing such a powder coating composition (PC), wherein all the components essential for a powder coating are extruded together with (i) composition (C) or (ii) the components of composition (C) and subsequently ground. Alternatively, (i) micronized composition (C) or (ii) the micronized components of composition (C) can be mixed with a ground and optionally sieved powder coating composition. DETAILED DESCRIPTION

[0021] Modified wax(mW)

[0022] The modified wax as a component of the composition (C) can in principle be any wax. For example, the wax (W) can be selected from the group consisting of synthetic organic waxes, semi-synthetic organic waxes, natural waxes (bio-based waxes) and mixtures thereof, wherein the wax is chemically modified. The modification of the unmodified wax is carried out by grafting α,β-unsaturated carboxylic acids and / or derivatives thereof, such as acrylic acid or maleic anhydride.

[0023] As wax components, synthetic hydrocarbon waxes, for example polyolefin waxes, are suitable. These can be prepared by thermal decomposition of branched or unbranched polyolefin plastics or by direct polymerization of olefins. As polymerization methods, for example free radical methods are considered, in which olefins, usually ethylene, are converted into more or less branched polymer chains under high pressure and temperature; in addition, methods are considered in which ethylene and / or higher 1-olefins, for example propylene, 1-butene, 1-hexene, etc. are polymerized to unbranched or (short-chain) branched waxes by means of organometallic catalysts, for example Ziegler-Natta or metallocene catalysts.

[0024] Corresponding processes for preparing olefin homopolymer waxes and olefin copolymer waxes are described, for example, in Ullmann's Encyclopedia of Industrial Chemistry, 5th edition, Volume A 28, Weinheim 1996, Chapters 6.1.1. / 6.1.2. (High-pressure polymerization (waxes), Chapter 6.1.2. (Ziegler-Natta polymerization, polymerization with metallocene catalysts) and Chapter 6.1.4. (Thermal decomposition).

[0025] For such waxes, sustainably produced polyolefins can also be used, which have been obtained from renewable or recycled materials. For example, EP2352772 describes how to produce polypropylene polymers from renewable raw materials. US2022098490 describes a method for preparing polyolefins from plastic waste.

[0026] Furthermore, so-called Fischer-Tropsch waxes can be used. These waxes are prepared catalytically using synthesis gas and differ from polyethylene waxes by having a lower average molar mass, a narrower molar mass distribution and a lower melt viscosity.

[0027] In addition, bio-based waxes can be used, wherein it is generally an ester wax. Generally, bio-based waxes are understood to be those waxes based on renewable raw materials. In this case, it can be either natural or chemically modified ester waxes. Typical natural bio-based waxes are described in Ullmann's Encyclopedia of Industrial Chemistry, Fifth Edition, Volume A 28, 1996, Chapter 2. Among them are palm waxes such as carnauba wax, grass waxes such as candelilla wax, sugarcane wax and straw wax, beeswax, rice wax, etc.

[0028] Chemically modified waxes are usually produced from ester waxes or vegetable oil-based fatty acids by oxidation (e.g. by a mixture of CrO3 and H2SO4), esterification, transesterification, amidation, hydrogenation, etc. Examples of these also include metathesis products of vegetable oils.

[0029] Bio-based waxes furthermore include montan waxes in unmodified or refined or derivatized form. Details of waxes of this type are found, for example, in Ullmann's Encyclopedia of Industrial Chemistry, 5th edition, volume A 28, 1996, chapter 3 (waxes).

[0030] In a preferred embodiment, the modified wax (mW) is selected from the group consisting of polyolefin waxes, montan wax, rice wax, beeswax, sunflower wax, corn wax, carnauba wax, oxides of rice wax, sunflower wax, corn wax or carnauba wax, Fischer-Tropsch wax, paraffin wax, ester wax and amide wax.

[0031] Among these waxes, polyethylene wax, polypropylene wax, poly(ethylene-co-propylene) wax and oxides of rice bran wax, corn wax or sunflower wax are particularly suitable because they are waxes with a relatively high melting point and have a light intrinsic color. Such waxes are particularly suitable for powder coatings because they are optically neutral and chemically stable, which is important for the preparation method of powder coatings.

[0032] Particularly preferred are polyethylene wax, polypropylene wax, poly(ethylene-co-propylene) wax, since these are phase mediating materials (having polar grafted non-polar polymer backbones) for interaction between the binder and the filler, and are particularly suitable for modification by grafting with α,β-unsaturated carboxylic acids and / or their derivatives, and undergo almost no undesirable side reactions.

[0033] Modified layered silicate (mP)

[0034] Layered silicates are silicates whose silicate anions consist of layers of SiO4 tetrahedra connected at their vertices. These layers or double layers are not connected to one another to form a framework via further Si-O bonds.

[0035] Such layered silicates are contained in naturally occurring clays. Clays are classified according to the predominant mineral component (e.g., kaolinite clay, smectite-rich clay). Clays in which the predominant clay mineral is a layered silicate are accordingly classified according to the layered silicate.

[0036] Sheet silicates in the sense of the present invention therefore include both pure clay minerals as sheet silicates and clays whose predominant clay mineral is a sheet silicate.

[0037] Likewise, organic three-layer minerals in the sense of the present invention include both pure clay minerals as organic three-layer minerals and clays in which the predominant clay mineral is an organic three-layer mineral.

[0038] The same definition applies to all clay minerals or clay mineral classes listed.

[0039] One type of clay with industrial importance is bentonite. In geology, the term "bentonite" is used for a type of clay rock type (clay rock, not clay mineral) that consists primarily of montmorillonite (a clay mineral of the smectite family). However, in commercial and industrial applications, the term "bentonite" is more generally used for all swellable clays that consist primarily of montmorillonite clay minerals (montmorillonite, bebeauite, nontronite) and that additionally contain additional components such as mica, illite, cristobalite and zeolites. This definition of bentonite also applies to the invention described in this patent application. Industrially important bentonites require a montmorillonite content of 60-80%.

[0040] The layered silicates can be modified by cation or anion ion exchange. Preferably, the interlayer cations are exchanged with other cations. For example, the interlayer cation sites can be exchanged with Na+ ions by alkaline activation.

[0041] Preference is given to three-layer minerals (2:1 phyllosilicates), the crystallographic structure of which consists of three superimposed tetrahedron-octahedron-tetrahedron layers (TOT layer unit).

[0042] The 2:1 layer structure (TOT) shows two tetrahedral (T) silicon dioxide (SiO2) layers electrostatically cross-linked via an octahedral (O) middle layer of Al2O3 or Fe2O3. The TOT base layers are not rigidly connected to each other, but are separated by an independent space: the middle layer containing hydrated cations and water molecules.

[0043] Particularly suitable are three-layer minerals from the smectite group. These include, for example, saponite, hectorite, montmorillonite, beibolite and nontronite. Preference is given to dioctahedral smectites, with particular preference being given to montmorillonite-containing minerals such as those found in bentonites.

[0044] The properties of three-layer minerals, in particular those of the smectite group and more preferably of bentonites, can be modified by exchanging the cations of the middle layer.

[0045] Active bentonite is for example initially calcium bentonite, wherein the original cation position of the middle layer has been exchanged by Na+ ions by means of alkali activation. In principle, calcium bentonite is converted into sodium bentonite. With regard to its physical properties, it is very similar to natural sodium bentonite. Such alkali-activated bentonite can be used in alternative embodiments of the present invention.

[0046] Preferred embodiments relate to organophilic modified three-layer minerals. Such organic three-layer minerals are prepared by embedding organic molecules into the middle layer or exchanging the cations of the interlayer with organic molecules. For the organic modification, the organic molecules considered are selected from the group consisting of polymers (nonionic, cationic or anionic), alkylammonium compounds, alcohols such as ethylene glycol, methanol or glycerol, and carbohydrates.

[0047] Preferably, the modification is carried out with alkylammonium compounds, particularly preferably with quaternary alkylammonium compounds. As a result of this hydrophobization, the composition (C) in the powder coating exhibits better structuring properties than in the case of an organophilic modification of the composition (C) without the layered silicate.

[0048] As the alkyl quaternary ammonium compound, a dimethyldialkylammonium ion or a trimethylalkylammonium ion is preferably used.

[0049] Modified three-layer minerals are preferably modified montmorillonite or modified hectorite. Particularly preferred are organophilic modified montmorillonite or hectorite. It is preferably carried out with an alkyl ammonium compound, and it is particularly preferred to be modified with an alkyl quaternary ammonium compound. Preferred examples are dimethyl distearyl ammonium hectorite, dimethyl distearyl ammonium bentonite, and montmorillonite modified with dimethyl distearyl ammonium. Commercially available materials are BENTONE 38V CG (dimethyl distearyl ammonium hectorite) and BENTONE 34 (dimethyl distearyl ammonium bentonite), both of which are available from Elementis Specialties, and Claytone-40 (stearin derivative of bentonite) of Byk Company. One, two or more of these organophilic modified bentonites can be used.

[0050] Very particularly preferably, as the organophilic modified montmorillonite, an organophilic modified bentonite is used. The organophilic modified bentonite is prepared by exchanging the cations of the intermediate layer for alkylammonium ions, preferably alkylquaternary ammonium ions. By this hydrophobization, the bentonite can swell in non-polar liquids. These bentonites are also referred to as "organic bentons (Bentone)" or "organoclays". By using organo-bentonite as a rheology modifier, the typical application areas of such organo-bentonite are the thickening of greases and lubricants and the thickening of coatings. Preferred examples are BENTONE 34 (dimethyl distearyl ammonium bentonite) of Elementis Specialties, and Claytone-40 (stearin derivative of bentonite) of Byk. One, two or more of these organo-modified bentons can be used.

[0051] Physical supply form

[0052] The two main components of composition (C), modified wax (mW) and modified layered silicate (mP), can be added to the powder coating in various forms. They can be present as granules or powders.

[0053] Preferably, the modified wax (mW) and the modified layered silicate (mP) are present in micronized form in the composition (C).

[0054] The expression "micronized" means in the present context that the (average) particle size of the substance in question has been reduced compared to the original state and that less than 1% by volume of the particles have a particle size of 1000 μm or more.

[0055] The particle size distribution can be measured, for example, by laser diffraction, as described, for example, in "A Guidebook to Particle Size Analysis" (Horiba Instruments, Inc., 2019). Suitable measuring instruments for this are, for example, the LA-960 from Horiba Instruments, Inc., which can measure particle sizes in the range of 10 nm to 5 mm, or the Mastersizer 3000 from Malvern Panalytical, which can measure particle sizes in the range of 10 nm to 3.5 mm.

[0056] The micronized composition (C) has a higher surface area than the non-micronized composition (C) and can be homogenized more easily and more quickly with the powder coating in an extruder than the non-micronized composition (C), so that the powder coating manufacturer has to consume less energy to prepare the powder coating.

[0057] Preference is given to compositions (C) in which the modified phyllosilicates (mP) and the modified waxes (mW) have a volume median D50 of the particle size of 500 μm or less, particularly preferably 300 μm or less.

[0058] In an alternative embodiment, the micronized, modified layered silicate (mP) is fully or partially coated with a modified wax.

[0059] The micronized, modified phyllosilicate particles can be mixed particularly efficiently with the modified wax (mW) by heat, thereby producing a free-flowing micronized product coated with the modified wax.

[0060] In this embodiment, the modified sheet silicate (mP) preferably has a volume median D50 of the particle size of ≤500 μm, particularly preferably ≤300 μm.

[0061] This embodiment is particularly preferred, since the preparation of the powder coating composition (PC) according to the invention by extrusion of all components of the powder coating and subsequent grinding necessarily consumes less energy than the addition of the essential micronized components of the composition (C) alone or in one of other ways mixed into the powder coating composition (PC) according to the invention. The preparation of the powder coating according to the invention is described in further detail below.

[0062] Preferred composition

[0063] PTFE-free compositions are particularly environmentally compatible, so that PTFE-free compositions (C) which produce a sufficient structuring effect in the baked powder coating are clearly preferred over PTFE-containing compositions in terms of environmental considerations.

[0064] In a preferred embodiment, the composition (C) comprises the modified wax (mW) and the modified bentonite (mB), preferably the organophilic modified bentonite (omB), in a ratio of between 4:1 and 1:3, preferably between 3.5:1 and 1:2, particularly preferably between 3:1 and 1:1.5 and very particularly preferably between 3:1 and 1:1.

[0065] The composition (C) comprises, in addition to the modified wax (mW) and modified layered silicate (mP) components necessary for structuring, an inorganic additive, preferably one or more alkaline metal compounds from the group consisting of (semi)metal oxides, (semi)metal sulfates, (semi)metal hydroxides, preferably semi-metal oxides, semi-metal sulfates, semi-metal hydroxides, more preferably selected from sulfates of alkaline earth metals or oxides of metals of the fourth subgroup, particularly preferably selected from barium sulfate, fumed silica and titanium dioxide. The composition (C) is particularly effective because such a composition also enhances the structuring effect.

[0066] The composition (C) according to the invention may additionally contain stabilizers, additives and / or flow aids, for example primary and secondary antioxidants (for example HALS compounds) or fumed silica.

[0067] Preparation method and use of the composition according to the invention

[0068] The composition (C) according to the invention is prepared by mixing the components by hot mixing, extrusion, grinding or vibration and in this case optionally simultaneously micronizing according to an aspect, wherein micronizing is understood to be comminuting to an average particle size of ≤ 1000 μm. Therefore, another subject of the present invention relates to a method for preparing the composition (C) according to the invention, comprising the following steps:

[0069] a) providing a modified, optionally micronized phyllosilicate (mP), an optionally micronized wax (mW) and optionally further components

[0070] b) The components provided in step a) are mixed and optionally micronized, preferably by blending, hot mixing, extrusion or grinding.

[0071] Blending is understood to mean physical mixing, for example by stirring, shaking or vortexing.

[0072] Hot mixing involves a preferred method for preparing composition (C) comprising the following steps:

[0073] a) providing and mixing a micronized, modified layered silicate (mP) and a modified wax (mW);

[0074] b) warming the modified wax (mW) to a temperature within the melting range of the wax while stirring;

[0075] c) Mix the components by stirring.

[0076] Another subject of the present invention is the use of the composition (C) according to the invention for structuring powder coatings. By using the composition (C) in powder coatings, the surface of the powder coating can be structured with a reduced amount or no PTFE-containing component.

[0077] Powder coating composition (PC)

[0078] Another subject of the present invention is a powder coating composition (PC) comprising

[0079] a) at least one thermoplastic or, after baking, thermosetting polymer,

[0080] b) at least one wax (mW) modified by grafting α,β-unsaturated carboxylic acids and / or derivatives thereof; and

[0081] c) at least one optionally micronized, modified phyllosilicate (mP).

[0082] Component a) is a binder.

[0083] Preferably, the powder coating composition (PC) comprises as binder a polymer which is thermoplastic after baking, selected from the group consisting of epoxy resins, epoxy / polyester hybrid systems, reactive polyesters or reactive acrylates, preferably from the group consisting of epoxy / polyester hybrid systems and hydroxyalkylamides.

[0084] In thermosetting powder coatings, the structure produced by composition (C) is stable even at elevated temperatures, whereas thermoplastic structured powder coatings can be deformed into a coating above the melting temperature.

[0085] The structuring of the surface can be further enhanced by adding one or more basic metal compounds from the group of (semi)metal oxides, (semi)metal sulfates or (semi)metal hydroxides, more preferably from the group of alkaline earth metal sulfates or oxides of metals of the fourth subgroup, particularly preferably from the group of barium sulfate, fumed silica and titanium dioxide, to the powder coating composition (PC). These basic metal compounds can already be present in the powder coating composition as pigments or fillers, or can be additionally added thereto.

[0086] By adding the composition (C) to the powder coating composition (PC), high roughness values ​​Rz (average roughness) and thus a strong structuring effect can be achieved.

[0087] By selecting an addition amount in the range of between 0.5% and 10% by weight, preferably between 2 and 8% by weight, based on the mass of the total powder coating composition (PC), the intensity of the structuring effect can be adjusted in a more favorable manner than in the case of PTFE-containing structuring additives. In the case of PTFE-containing structuring additives, by contrast, even in the case of very small addition amounts, a strong structuring effect is produced without such good adjustability.

[0088] For the roughness of the surface of the powder coating composition (PC), the ratio in which the essential components of the composition (C) are present is important. High roughness values ​​are obtained when the ratio of wax (mW) to bentonite (omB) is between 4:1 and 1:3, preferably between 3.5:1 and 1:2, particularly preferably between 3:1 and 1:1.5, very particularly preferably between 3:1 and 1:1.

[0089] Powder coatings containing small amounts of PTFE are more environmentally compatible than powder coatings with a higher PTFE content. Therefore, a preferred subject matter of the present invention is a powder coating composition (PC) containing less than 1% by weight of PTFE, preferably 0.5% by weight, particularly preferably 0.1% by weight and very particularly preferably no PTFE.

[0090] The powder coating composition (PC) according to the present invention is prepared by a method for preparing a powder coating composition (PC) comprising the following steps:

[0091] a) providing all the essential components of the powder coating composition and composition (C) or the individual components comprised by composition (C);

[0092] b) mixing the components provided in step a) by extrusion;

[0093] c) grinding the powder coating composition extruded in step b).

[0094] The ground powder coating composition from c) can optionally subsequently be sieved.

[0095] In an alternative embodiment, (i) composition (C) or (ii) individual components of composition (C) may be added to the powder coating composition (PC) and blended therewith after process step c).

[0096] Experimental part:

[0097] The examples illustrate some preferred embodiments of the invention.

[0098] Table 1: Methods used to determine the given parameters

[0099]

[0100]

[0101]

[0102]

[0103] Components W and B from Table 2 were mixed by shaking and then added to the powder coating composition. Alternatively, the components were added directly to the powder coating composition.

[0104] Preparation of the powder coating composition (PC) and the corresponding coating according to the present invention:

[0105] The various components listed in Tables 3 to 5 were premixed in a mixer at maximum power for 3 min and then mixed in an extruder at about 110° C. (extruder temperature). In this case, it was ensured that the product temperature did not exceed 140° C.

[0106] Extruder settings:

[0107] A) Primid system

[0108]

[0109] B) Mixed system

[0110]

[0111] Subsequently, the powder coating was ground and sieved to less than 125 μm. In this case, the D50 value should be about 40-45 μm. Subsequently, the powder coating composition was sprayed on a metal substrate (aluminum).

[0112] The powder coating was baked at 180°C for 15 min.

[0113] Table 3: Formulation of pigmented mixed system L1

[0114]

[0115] Table 4: Structuring components (SC) in L1 (Mixed Blue)

[0116]

[0117] Table 4 shows that the composition (C) consisting of the MA-grafted wax and the organo-modified bentonite combination produces a roughness value Rz (Examples 4-9) higher than the two components (Examples 2 and 3) alone. The composition containing additional modified bentonite instead of organo-modified bentonite produces a smaller structuring effect (Examples 10-12). As shown in Examples 13 and 14, the functionality of the wax used plays a special role in the generation of structuring. The embodiment 13 containing unfunctionalized wax and the embodiment 14 containing polar polyolefins do not show a structuring effect. Therefore, the modification type of polyolefin plays a decisive role in the generation of structuring. When the composition (C) contains a certain amount of PTFE in addition, a particularly strong structuring can be achieved.

[0118] The graph of the roughness values ​​of the powder coating composition (PC) in L1 without PTFE is shown in Figure 1 .

[0119] Table 5: Formulation of white mixed system L2

[0120] Element 1.0% share 2.0% share 4.0% share Crylcoat 1770-0 420.50 416.2 407.9 DER663U-E 180.20 178.4 174.8 Additol P 896 39.60 39.2 38.4 Benzoin 3.30 3.2 3.2 Blancfixe F 86.60 85.8 84.0 Kronos 2160 259.80 257.2 252.0 W+B or Z (see Table 8) 10 20 40

[0121] Table 6: Structuring component (SC) in L2 (mixed white)

[0122]

[0123] In white mixed coatings, by adding 4% by weight of the composition Z2 according to the invention, a stronger structuring effect can be achieved than with conventional amounts of PTFE-containing additives (see Table 6).

[0124] Table 7: Formulation of Primid system L3

[0125] Element none 1.0% share 2.0% share 4.0% share Crylcoat 2617-3 584.0g 575.0g 566.0g 560.64 Primid XL 552 31.0g 30.5g 30.0g 29.76 Additol P 824 30.0g 29.5g 29.1g 28.8 Benzoin 5.0g 5.0g 4.9g 4.8 Kronos 2310 340.0g 340.0g 340.0g 340 Hostaperm-Blau A4R 10.0g 10.0g 10.0g 10 W+B or Z (see Table 4) -- 10.0 g 20.0g 40

[0126] Table 4: Structural component (SC) in L3 (Primid Blue)

[0127]

[0128] It is clear from Table 4 that structuring of the powder coating can be achieved by adding composition (C), and this can be adjusted according to the amount of composition (C) added. In addition, it was observed that in the case of a ratio of modified wax (mW) to modified bentonite (mB) of 2:1 (Example 1, Z1), a stronger structuring effect can be achieved compared to the case of a composition (C) with a lower ratio (Examples 2-3).

Claims

1. A structured composition (C) for powder coatings, comprising (a) at least one wax (mW) modified by grafting α,β-unsaturated carboxylic acids and / or derivatives thereof; and (b) Modified layered silicates (mP), preferably organophilically modified layered silicates (omP).

2. The composition (C) according to claim 1, characterized in that The modified phyllosilicate (mP) is a modified three-layer mineral, preferably a modified smectite or a modified hectorite, particularly preferably a modified bentonite (mB), very particularly preferably an organophilic modified bentonite (omB).

3. The composition (C) according to claim 1 or 2, characterized in that The modified layered silicates (mP) are organophilically modified, preferably with alkylammonium compounds, particularly preferably with quaternary alkylammonium compounds.

4. Composition (C) according to any one of the preceding claims, characterized in that The modified wax (mW) and the modified phyllosilicate (mP) are present in micronized form, or the modified phyllosilicate (mP) is completely or partially coated with the modified wax (mW).

5. A composition (C) according to any one of the preceding claims, wherein The modified wax (mW) is selected from the group consisting of synthetic organic waxes, semi-synthetic organic waxes, natural waxes and mixtures thereof, preferably selected from polyolefin waxes, montan waxes, rice bran waxes, beeswax, sunflower waxes, corn waxes, carnauba waxes, Fischer-Tropsch waxes, paraffin waxes, ester waxes and amide waxes, more preferably selected from polyethylene waxes, polypropylene waxes, poly(ethylene-co-propylene) waxes, rice bran waxes, corn waxes and sunflower waxes, more preferably selected from polyethylene waxes, polypropylene waxes, poly(ethylene-co-propylene) waxes.

6. Composition (C) according to any one of the preceding claims, characterized in that The weight ratio of the modified wax (mW) to the modified phyllosilicate (mP), preferably to the modified bentonite (mB), particularly preferably to the organophilic modified bentonite (omB) is between 4:1 and 1:3, preferably between 3.5:1 and 1:2, particularly preferably between 3:1 and 1:1.5, very particularly preferably between 3:1 and 1:

1.

7. Composition (C) according to any one or more of the preceding claims, characterized in that The composition comprises an inorganic additive, preferably one or more alkaline metal compounds from the group of (semi)metal oxides, (semi)metal sulfates or (semi)metal hydroxides, more preferably selected from alkaline earth metal sulfates or oxides of metals of the fourth subgroup, particularly preferably selected from barium sulfate, fumed silica and titanium dioxide.

8. Composition (C) according to any one or more of the preceding claims, characterized in that The composition (C) contains less than 1% by weight of PTFE, preferably 0.5% by weight, particularly preferably 0.1% by weight and very particularly preferably no PTFE.

9. A method for preparing a composition (C) according to any one of claims 1 to 8, comprising the following steps: a) providing an optionally micronized, modified phyllosilicate (mP), a modified, optionally micronized wax (mW) and optionally further components b) The components provided in step a) are mixed and optionally micronized, preferably by blending, hot mixing, extrusion or grinding.

10. The method for preparing composition (C) according to claim 9, comprising the following steps: a) providing and mixing a micronized, modified layered silicate (mP) and a modified wax (mW); b) warming the modified wax (mW) to a temperature within the melting range of the wax while stirring; c) Mix the components by stirring.

11. Use of a composition (C) according to any one of the preceding claims for structuring powder coatings.

12. A powder coating composition (PC) comprising a) at least one thermoplastic or, after baking, thermosetting polymer, b) the composition (C).

13. The powder coating composition (PC) according to claim 12, characterized in that The polymer which is thermosetting after baking is selected from the group consisting of epoxy resins, epoxy resin / polyester hybrid systems, reactive polyesters or reactive acrylates, preferably selected from the group consisting of epoxy resin / polyester hybrid systems and hydroxyalkylamides.

14. Powder coating composition (PC) according to any one or more of claims 12 to 13, characterised in that The composition comprises an inorganic additive, preferably one or more alkaline metal compounds from the group of (semi)metal oxides, (semi)metal sulfates or (semi)metal hydroxides, more preferably selected from sulfates of alkaline earth metals and oxides of metals of the fourth subgroup, particularly preferably selected from barium sulfate, fumed silica and titanium dioxide.

15. Powder coating composition (PC) according to any one or more of claims 12 to 14, characterised in that The amount of the composition (C) in the powder coating composition (PC) is between 0.5 and 10 wt.-%, preferably between 2 and 8 wt.-%, based on the mass of the total powder coating composition (PC).

16. Powder coating composition (PC) according to any one or more of claims 12 to 15, characterised in that The weight ratio of the modified wax (mW) to the modified phyllosilicate (mP), preferably to the modified bentonite (mB), particularly preferably to the organophilic modified bentonite (omB) is between 4:1 and 1:3, preferably between 3.5:1 and 1:2, particularly preferably between 3:1 and 1:1.5, very particularly preferably between 3:1 and 1:

1.

17. Powder coating composition (PC) according to any one or more of claims 12 to 16, characterised in that The powder coating composition (PC) contains less than 1% by weight of PTFE, preferably 0.5% by weight, particularly preferably 0.1% and very particularly preferably no PTFE.

18. A method for preparing a powder coating composition (PC) according to any one of claims 12 to 17, comprising the following steps: a) providing all the essential components of the powder coating composition and (i) composition (C) or (ii) the individual components comprised by composition (C); b) mixing the components provided in step a) by extrusion; c) grinding the powder coating composition extruded in step b), d) optionally sieving the ground powder coating composition from c).

19. A method for preparing a powder coating composition (PC) according to any one of claims 12 to 17, comprising the following steps: a) providing a ground and optionally sieved powder coating composition which does not comprise composition (C), b) mixing the powder coating composition with (i) the micronized composition (C) or (ii) the individual micronized components comprised by the composition (C).

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