Coated metal sheet, coating compositions

Abstract

A coated metal sheet obtainable by a process for producing a coated metal sheet comprising the following steps: (i) providing a metal sheet; (ii) applying a coating composition to at least one side of the metal sheet; and (iii) baking the coating composition; wherein - the coating composition comprises a thermoplastic polymer; - the coating composition is a dispersion comprising the thermoplastic polymer in the form of dispersed particles; - the dispersed particles have an average particle diameter of at least 10 µm; - the coating composition does not comprise a fluorinated compound; and - the application of the coating composition comprises dip coating, knife coating, pouring, roll coating or a combination of two or more thereof.

Description

Field of the invention

[0001] The present invention relates to a method for producing a coated metal sheet. The present invention further relates to a coated metal sheet. The present invention further relates to coating compositions for producing a coated metal sheet. Finally, the invention relates to the use of the coated metal sheet. Background of the invention

[0002] PTFE coatings are known from the state of the art; they are usually applied as a triple coating for high-quality cookware. First, a base layer (inner layer), usually consisting of a binding resin dissolved in a solvent, for example, PAI dissolved in NMP, is wet-sprayed, dried, and pre-crosslinked. Subsequently, a transition layer and a top layer are sprayed wet-on-wet, with the top layer essentially containing fluoropolymer, usually PTFE. The entire coating is then baked for approximately 10 minutes at 420°C. These coatings can be modified with pigments and various fillers.

[0003] The use of fluoropolymers such as PTFE is disadvantageous in this context, primarily due to the fact that the curing temperature at which a PTFE-containing coating is applied to a substrate is significantly higher than the decomposition temperature of PTFE, which can result in the formation of hazardous substances, particularly per- and polyfluorinated alkyl substances (PFAS). The use of bisphenols and polyethersulfones in corresponding coatings can also be critical for health and environmental reasons. Object of the invention

[0004] It is therefore the object of the present invention to provide a coated metal sheet, a method for producing the same and coating compositions for producing the same which overcome the disadvantages of the prior art, in particular to provide a high-quality coating on metal sheets without the use of critical substances, in particular without fluoropolymers and without PFAS (per- or polyfluorinated alkyl substances), but preferably also without bisphenol or polyethersulfone. Disclosure of the invention

[0005] This object is achieved according to the subject matter of the independent claims. Preferred embodiments emerge from the subclaims and the following description.

[0006] The object is achieved in particular by a method for producing a coated metal sheet, which comprises the following steps: (i) providing a metal sheet; (ii) applying a coating composition to at least one side of the metal sheet; and (iii) baking the coating composition;wherein - the coating composition comprises a thermoplastic polymer; - the coating composition is a dispersion comprising the thermoplastic polymer in the form of dispersed particles; - the dispersed particles have an average particle diameter of at least 10 µm; - the coating composition does not comprise any fluorinated compound, in particular any fluoropolymer, any per- and polyfluoroalkyl substances, any polytetrafluoroethylene, any hexafluoropropylene oxide dimer acid (GenX), any bisphenol, any polyethersulfone, any N-methyl-2-pyrrolidone and any N-ethyl-2-pyrrolidone; and - the application of the coating composition comprises dip coating, knife coating, pouring, roll coating or a combination of two or more thereof.

[0007] The object is further achieved by a coated metal sheet which can be obtained by the process according to the invention, the coated metal sheet comprising - a metal sheet; and - a coating on at least one side of the metal sheet.

[0008] The object is further achieved by a coating composition for producing an inner partial layer of a coated metal sheet, comprising: - 100 parts by weight of a solvent, based on the total weight of the coating composition; and - 5 to 50 parts by weight of a solid mixture, based on the total weight of the coating composition, wherein the solid mixture is dispersed in the solvent mixture; where - the solid mixture contains 80 to 120 parts by weight of a thermoplastic polymer, wherein the thermoplastic polymer is selected from the group consisting of a polyaryletherketone (PAEK), a polyarylene sulfide, and a mixture of two or more thereof, based on the total weight of the solid mixture; and wherein the coating composition does not comprise a fluoropolymer and preferably does not comprise a bisphenol and / or polyethersulfone.

[0009] The object is further achieved by a coating composition for producing an outer partial layer of a coated metal sheet, comprising: - 40 to 100 parts by weight of a solvent, based on the total weight of the coating composition; and - 5 to 40 parts by weight of a silicone oil, a silicone resin or a mixture of two or more thereof; where - is an organic solvent with a boiling point of more than 100°C under normal pressure or consists of a mixture of two or more solvents each with a boiling point of more than 100°C under normal pressure; wherein the coating composition does not comprise a fluoropolymer and preferably does not comprise a bisphenol and / or polyethersulfone.

[0010] The object is further achieved by a coating composition for producing an outer partial layer of a coated metal sheet, comprising: - 100 parts by weight of a solvent, based on the total weight of the coating composition; and - 5 to 50 parts by weight of a solid mixture, based on the total weight of the coating composition, wherein the solid mixture is dispersed in the solvent mixture; where - the solvent is an organic solvent with a boiling point of more than 100°C under normal pressure or consists of a mixture of two or more solvents each with a boiling point of more than 100°C under normal pressure; - the solid mixture contains 70 to 100 parts by weight of a thermoplastic polymer, wherein the thermoplastic polymer is selected from the group consisting of a polyaryletherketone (PAEK), a polyarylene sulfide, a polyimide, and a mixture of two or more thereof, based on the total weight of the solid mixture; and wherein the coating composition does not comprise a fluoropolymer and preferably does not comprise a bisphenol and / or polyethersulfone.

[0011] Finally, the problem is solved by using the coated metal sheet as a component of a cooking or baking accessory, preferably a pan, a pot or a baking pan, a storage tray, a storage cage or as a component of a conveyor belt. Method for producing a coated metal sheet

[0012] A first aspect of the present invention relates to a method for producing a coated metal sheet. Surprisingly, it was found that the method according to the invention, as described in detail below with reference to preferred embodiments, leads to the production of a coated metal strip that was particularly easy to process. In particular, no significant detachment of the coating from the metal sheet was observed, and high scratch resistance was observed. In particular, in tests below 20 N using an Ericsson test bar, no detachment was observed, but only plastic indentations. Even with tight forming of the coated sheets with a radius of only 0.5 mm, no detachment occurred. In particular, the metal sheet coated in this way can be dry formed without the need to add oil or adhere an additional film.Bearings manufactured in this way from sheet metal coated according to the invention have particularly good wear properties.

[0013] In particular, the coated metal sheet according to the invention can be understood as a pre-coated metal sheet. In this context, a pre-coated metal sheet refers to a coated metal sheet that, after the coating has been applied to the metal sheet, is converted by forming into a product intended for use, such as a product with a storage function, baking or cooking accessory, preferably a pan or pot, with a non-stick effect. Surprisingly, it has been found that the coating in the coated metal sheet according to the invention survives subsequent forming without (significant) damage. The advantages of the coating are thus reflected in the properties of the formed material. The subsequent forming can be embossing, drawing, rolling, bending, punching, or a combination of two or more thereof.Within the scope of the invention described herein, corresponding products can be manufactured more cost-effectively and with higher quality than is possible with the prior art. For example, a king cake mold or a bearing with a layer thickness of 40-50 µm can be manufactured easily and cost-effectively. Providing a metal sheet

[0014] The method for producing the coated metal sheet comprises, as a first step, providing a metal sheet.

[0015] The metal sheet can be a metal strip, a metal sheet (such as a rolled-up metal sheet ("coil")), a pre-coated metal sheet, a round blank (round sheet metal cut), a square blank, for example, for the production of baking trays, or a Gastro-Norm container (BN container). Blanks, cut-outs, and GN containers can be coated while lying on a conveyor belt, for example. For blanks, especially pan blanks, the coating can be applied using pad printing.

[0016] The metal sheet may be single-layer or multi-layer, in the latter case the metal sheet comprises or consists of several metal layers in direct contact with one another, wherein the metal or metals forming the respective metal layers may be independently the same or different.

[0017] The metal sheet essentially comprises or (preferably) consists of one metal or a mixture of two or more metals. Preferably, the metal can be independently selected from the group consisting of aluminum, iron, especially stainless steel, aluminized steel, galvanized steel, chromated steel, nickel-plated steel, titanium, and copper, and mixtures thereof, especially multilayer materials such as steel / aluminum / steel.

[0018] The metal sheet may have a thickness in a range of 0.05 to 5 mm, preferably 0.1 to 3 mm. The metal sheet may be made of steel and have a thickness in a range of 0.1 to 1 mm, preferably 0.15 to 0.6 mm. The metal sheet may be made of aluminum, copper, titanium, or a mixture of two or more thereof, preferably made of aluminum, and have a thickness in a range of 1 to 3 mm, preferably 1.5 to 2.5 mm. The metal sheet may be a multi-layer material and have a total thickness of 0.9 to 2.6 mm, wherein the multi-layer material preferably has a steel / aluminum / steel structure and the steel layers each have a thickness of no more than 0.6 mm.

[0019] The thicknesses specified here, in particular of the metal sheet and the coating, are determined in accordance with the standard DIN EN ISO 2808:2019-12 in the version valid on the priority date. The specified coating thicknesses are averaged values ​​resulting from at least 3 measurements at one location and at least 3 different locations on a surface. The coating thickness is measured using a coating thickness gauge, e.g. the “QNIX 4500” device from Automation Dr. Nix GmbH & Co KG. For non-magnetic substrates and coatings, the measurement is carried out using eddy current (DIN EN ISO 2360 in the version valid on the priority date, ASTM D7091 in the version valid on the priority date). The principles of measurement technology are observed (DIN 1319, Part 1 and Part 3 in the version valid on the priority date). Applying a coating composition

[0020] In a next process step, a coating composition is applied to at least one side of the metal sheet. The coating composition can be applied to the entire corresponding side (entire corresponding surface) of the metal sheet or only to a portion of it.

[0021] According to the invention, the application of the coating composition comprises dip coating, knife coating, pouring, roll coating, or a combination of two or more thereof. Surprisingly, it has been found that the coating composition containing at least technically insoluble thermoplastics such as PEEK, PPS, etc., without soluble components such as PAI or PES, in an aqueous or substantially water-containing dispersion can be applied by these techniques, optionally dried, optionally tempered, and also baked above the liquidus temperature of the thermoplastics, resulting in a uniform and smooth coated metal sheet that can be used advantageously for non-stick, wear-resistant, anti-friction, and insulating applications. Other non-aqueous solvents are also possible, whereby the nature of the thermoplastic polymer powder particles remains unchanged.

[0022] The application can be done using the coil coating process.

[0023] It can be provided that the application comprises or is a step of dipping the metal sheet into the coating solution, followed by a step of rolling the resulting metal sheet wetted with the coating solution. This allows a particularly uniform coating to be achieved.

[0024] A dipping step for applying the coating composition is particularly advantageous because it does not produce any overspray and therefore no waste, and the metal sheet can be surrounded and wetted on all sides by the dispersion liquid.

[0025] For example, the coating composition can be applied using coating rollers. For example, at least two rollers, each running uniformly or in opposite directions, are used. The coating composition is applied to the first roller. From there, the coating composition is evenly transferred directly or indirectly to a second roller, the coating roller. From there, the coating composition is applied to the metal strip to be coated. This type of coating (roller application) is advantageous for coating both sides of the metal strip with different layer thicknesses or with different layer compositions. Single-sided coating is also easily possible.

[0026] In a preferred process step, the application can comprise one or more of the following sub-steps: A metal strip, preferably with a thickness of between 0.05 mm and 3 mm, is unwound and coated across its entire width or part of its width by co-rotating or counter-rotating coating rollers. Two or three rollers are used to evenly distribute the coating composition (“lacquer”). The coating composition is as defined herein. The coating composition is contained in a container from which the required amount is pumped out and poured onto the metering roller, so that a bead of lacquer is formed between the metering roller and coating roller or between the metering roller and transfer roller. The coating composition is then applied via the coating roller to the metal strip, which may have been previously cleaned, degreased and, if necessary, roughened and / or provided with an adhesion promoter.Titanates, zirconates, silanes, as well as metals and their oxides, for example chromium, nickel, aluminum, etc., serve as adhesion promoters.

[0027] The coated strip enters an oven chamber to vent the solvent and is dried, forming a powdery coating consisting of the solid substances in the dispersion. Upon further heating in a hotter oven zone, the thermoplastic material liquefies and spreads to form a uniform liquid film on the metal strip, thereby building up adhesion.

[0028] The strip is then cooled, and the applied material solidifies into a solid, uniform coating. Finally, the metal strip is coiled. For further processing, the coated metal strip is uncoiled at the customer's site and processed in conventional deep-drawing, forming, or stamping presses.

[0029] Surprisingly, the formation of a homogeneous and continuous coating in conjunction with the described roller application process is possible with very thin layers, namely thinner than the average particle size. Layer thicknesses in the range of 4-8 µm were achieved with powder grain sizes of D50 = 25 µm. This is important because grinding the thermoplastic high-performance polymers is very expensive, and the costs increase exponentially with decreasing grain size.

[0030] According to the invention, the coating composition is a dispersion comprising the thermoplastic polymer in the form of dispersed particles. The dispersed particles have an average particle size (particle diameter) D50 of at least 10 µm. It can be provided that the dispersed particles have an average particle diameter selected from the group consisting of at least 15 µm, at least 20 µm, at least 25 µm, and at least 30 µm. In this context, it can be provided that the particles have an average particle size (particle diameter) D50 of 60 µm or less, 50 µm or less, 40 µm or less, 30 µm or less, or 25 µm or less according to ISO 13320-1 in the version valid on the priority date. The particle size D50 is a statistical characteristic value derived from a particle size distribution.It describes the particle size below which 50% of the total mass of the particles lies.

[0031] It may be provided that a mixture of particles of different average particle sizes D50 is included in the dispersion.

[0032] The dispersion may have a solids content of at least 5 wt.%, at least 7.5 wt.%, or at least 10 wt.%, based on the total weight of the dispersion. The dispersion may have a solids content of at most 50 wt.%, at most 40 wt.%, or at most 30 wt.%, based on the total weight of the dispersion. By using appropriate amounts, the viscosity of the dispersion can be adjusted and a favorable coating thickness can be achieved.

[0033] The dispersion may be an aqueous dispersion. The aqueous dispersion may be completely aqueous, i.e., comprise water as the sole dispersant. Alternatively, the aqueous dispersion may contain, in addition to water, at least one solvent, preferably an alcohol, for example, ethylene glycol, propylene glycol, or isopropanol. Frost resistance for transport can be achieved, for example, by adding ethylene glycol, propylene glycol, or isopropanol.

[0034] The aqueous dispersion may further contain one or more coating additives. The coating additive may be selected from the group consisting of a thickener, a wetting agent, a defoamer, and an adhesion promoter (preferably zirconate, titanate, or silane). These can be decomposed during the tempering or baking process and are then no longer present in the final coating.

[0035] The thickener may be an acrylate. The acrylate may be an acrylate resin and / or an acrylic copolymer.

[0036] It may be provided that the acrylate resin has a viscosity of 400 to 1200 mPas·s, 500 to 1100 mPas·s, or 550 to 1070 mPas·s, according to DIN 51562-1 in the version valid on the priority date.

[0037] It can be provided that the acrylate resin has a weight-average molecular weight (Mw) of 100,000 to 500,000 g / mol, of 100,000 to 300,000 g / mol, of 100,000 to 200,000 g / mol, or of 120,000 to 160,000 g / mol, for example, about 140,000 g / mol, measured by GPC. For the corresponding GPC measurement, 8 mg of the sample was dissolved in 8 ml of 1,2,4-trichlorobenzene at 160°C for 90 min. Then, 200 µl of the sample solution was introduced into the high-temperature GPC equipped with IR5, an infrared detector (Polymer Char, Spain), at a flow rate of 0.5 ml / min at 145°C in the column zone and 160°C in the detector zone. injected. The data were processed using GPC One® software (Polymer Char, Spain).

[0038] It may be provided that the acrylic resin has a glass transition temperature of 30 to 40°C or of 32 to 36°C, for example about 34°C, according to ISO 11337-1 in the version valid on the priority date.

[0039] The coating composition may comprise an additive. The additive may be a dispersant, for example a multifunctional amino alcohol additive such as 2-amino-2-methyl-1-propanol, a lubricant such as titanium dioxide, or a crosslinking agent, in particular a crosslinking agent for crosslinking silicone oils and / or resins, or a mixture of two or more thereof.

[0040] It can be provided that the application is carried out multiple times. In this context, it can be provided that after one, after several or (preferably) after each application step, the coating composition thus applied is baked before the next coating composition is applied. In this case, it can be provided that the baking temperature in each subsequent step is the same as or preferably lower than each baking temperature in one of the preceding baking steps. In this way, the required layer thickness or the desired properties can be achieved. In particular, high coating thicknesses that are greater than the thickness of the metal sheet can be achieved and the metal sheet can be tightly sealed, i.e. a tight coating can be produced.

[0041] It can be provided that the application is carried out multiple times and that a different coating composition is used in at least one application step than in the remaining application steps. According to the invention, it is only necessary that at least one of the applied coating compositions, preferably the coating composition that is applied directly to the metal sheet, comprises the thermoplastic polymer, which is preferably selected from the group consisting of a polyaryletherketone (PAEK), a polyarylene sulfide, or a mixture of two or more thereof.In one or more further layer(s), preferably in layers which are not in direct contact with the metal sheet, a thermoplastic polymer may be comprised, which is preferably selected from the group consisting of a polyaryletherketone (PAEK), a polyarylene sulfide, a polyimide, a polyamideimide or a mixture of two or more thereof, preferably of a polyaryletherketone (PAEK), a polyarylene sulfide, a polyimide or a mixture of two or more thereof.

[0042] The coating does not comprise any fluoropolymer, in particular any PTFE, i.e., it is free of any fluoropolymer, in particular PTFE. According to the invention, this is particularly the case if the coating comprises a maximum of 1000 ppb, preferably a maximum of 100 ppb, particularly preferably a maximum of 25 ppb of total fluorides, measured by combustion ion chromatography (TOF-CIC).

[0043] Specifically, to perform the combustion ion chromatography (TOF-CIC) measurement method, coating samples are placed in ceramic boats and introduced into a furnace, where pyrohydrolysis takes place at 900–1000°C in a humid, O2-rich environment. Under these conditions, the samples are oxidized, the strong carbon-fluorine bond is broken, and the vapors are passed through an absorption solution containing Ar. The HF produced during the combustion of organic fluorine dissociates in the absorption solution to form H + - and F - -ions. The absorption solution samples, which also contain an internal standard for calibrating the analytical results, are then transferred to an ion chromatograph for analysis, where fluoride is measured.

[0044] It may be provided that all applied coating compositions do not contain bisphenol. Bisphenols are a group of chemical compounds consisting of two phenol groups linked together via a bridge structure—often via a carbon or other alkyl radical. It may be provided that all applied coating compositions do not contain substances used to produce bisphenols. It may be provided that all applied coating compositions do not contain polyethersulfone. It may be provided that the coating composition does not contain any fluoropolymer, per- and polyfluoroalkyl substances, polytetrafluoroethylene, hexafluoropropylene oxide dimer acid (GenX), PFSA, PFOA, bisphenol, and preferably also any substances for the production of which bisphenols are used, polyethersulfone, N-methyl-2-pyrrolidone, and N-ethyl-2-pyrrolidone.

[0045] The terms "free from," "does not contain," "does not comprise," and similar terms in this context do not exclude impurities that cannot be removed by conventional purification steps of the commercially available materials used. Impurities have no technical impact on the objective of the present invention.

[0046] The coating composition comprises a thermoplastic polymer. A thermoplastic polymer is a plastic that softens or melts when heated, allowing it to be shaped or processed, and solidifies again when cooled without undergoing any chemical change.

[0047] The thermoplastic polymer contained in the coating composition may be selected from the group consisting of a polyaryletherketone (PAEK), a polyarylene sulfide, and a mixture of two or more thereof. It may be provided that the thermoplastic polymer contained in the coating is selected from the group consisting of a polyaryletherketone (PAEK), a polyarylene sulfide, or a mixture of two or more thereof.

[0048] The preferred thermoplastics are for continuous temperature use above 220°C, preferably above 240°C, and then preferably selected from the group PAEK (PEEK, PEK, PEKK, PEKEKK etc. and their copolymers) and PPS.

[0049] Preferably, at least two PAEK polymers, or at least one PAEK polymer and PPS polymer can be included in the coating composition. Preferably, the at least two PAEK polymers, or at least one PAEK polymer and at least one PPS polymer, have different melting temperatures. Preferably, the two PAEK polymers, or at least one PAEK polymer and at least one PPS polymer, have different melt viscosities, measured according to ISO 11443 at 400°C in the version valid on the priority date. Preferably, the average melt viscosity of at least one thermoplastic polymer is more than 150 Pa.s, preferably 200-500 Pa.s, more preferably 300 to 500 Pa.s, measured according to ISO 11443 at 400°C in the version valid on the priority date. This primarily improves the adhesion of the second layer to the first layer.The average melt viscosity of at least one further thermoplastic polymer is preferably at most 150 Pa.s, preferably at most 120, more preferably at most 100 Pa.s, or especially preferably at most 90 Pa.s, measured according to ISO 11443 at 400°C in the version valid on the priority date. This allows the flow to be achieved much more smoothly upon heating on a surface to be coated. The non-stick effect of the coated surface is thereby improved. This applies even if the particles are large relative to the layer thickness (e.g., 25 µm grain size D50 for 25 µm layer thickness).

[0050] The coating composition preferably comprises at least two thermoplastic polymers, and preferably powder particles comprising a first thermoplastic polymer have a mass-related grain size distribution D50, measured by static image analysis according to ISO 13322-1:2014, of at most 70 µm, preferably at most 60 µm, more preferably at most 50 µm, even more preferably at most 40 µm, in particular at most 30 µm, and preferably powder particles comprising a second thermoplastic polymer have a mass-related grain size distribution D50, measured by static image analysis according to ISO 13322-1:2014, of at most 30 µm, preferably 25 µm, more preferably at most 20 µm, even more preferably at most 15 µm, particularly preferably 10 µm. This can increase the mechanical resistance.Even small mass-related concentrations of PEK and / or PEKK as the second thermoplastic polymer of at least 2 wt.%, preferably at least 5 wt.%, particularly preferably at least 10 wt.% result in a wear-reducing effect. Conversely, the use of PPS as the first thermoplastic polymer in an amount of up to 80 wt.%, 90 wt.%, or 95 wt.% can further reduce the baking temperature during coating production and further improve the non-stick effect of the resulting coating.

[0051] It can be provided that the thermoplastic polymer is at least one thermoplastic polymer with an average melt viscosity of more than 150 Pa.s, preferably 200-500 Pa.s, more preferably 300 to 500 Pa.s, and preferably also a thermoplastic polymer with an average melt viscosity of at most 150 Pa.s, preferably at most 120, more preferably at most 100 Pa.s or particularly preferably at most 90 Pa.s, measured according to ISO 11443 at 400°C in the version valid on the priority date. By using a thermoplastic polymer with an average melt viscosity greater than or equal to 150 Pa.s, the adhesion to the metal sheet as well as the mechanical strength and ductility are improved. By using another thermoplastic polymer with an average melt viscosity of at most 150 Pa.s, the leveling of the coating during production is improved.In addition, the production of a sufficiently fine-particle (relative to the solids) dispersion is facilitated.

[0052] The PAEK, preferably the PEEK, may have a density of 1.27 to 1.37 g / cm3, of 1.30 to 1.34 g / cm3, for example about 1.32 g / cm3, according to ISO 1183 in the version valid on the priority date.

[0053] The PAEK, preferably PEEK, can have a continuous service temperature of more than 250°C, from 250°C to 300°C, for example 260°C (or 260°C) or more. The continuous service temperature is the highest temperature at which a polymer or plastic can be used for a long period of time (typically ≥ 20,000 hours) without significant deterioration of its mechanical, electrical, or thermal properties.

[0054] The PAEK, preferably the PEEK, may have a glass transition temperature of 130°C to 160°C or of 140°C to 150°C, for example of about 143°C, as measured by DSC.

[0055] The PAEK, preferably the PEEK, may have a melting temperature of 300°C to 400°C, of ​​320°C to 360°C or of 340°C to 350°C, for example of about 343°C, as measured by DSC.

[0056] The PAEK, preferably the PEEK, may have a König hardness of 150 to 250 sec., of 180 to 220 sec., or of 190 to 210 sec., for example about 200 sec., according to ISO 1522 in the version valid on the priority date.

[0057] The PAEK, preferably the PEEK, can have a drying temperature of 100 to 200°C, for example of about 150°C, with a drying time of 1 to 5 h, for example about 3 h.

[0058] Corresponding PAEKs, in particular PEEKs, with one or preferably more of the properties described above have proven to be particularly suitable for producing a coating with similar or even better properties compared to a corresponding PTFE-containing coating.

[0059] It may be provided that the polyarylene sulfide is a polyphenylene sulfide (PPS).

[0060] It can be provided that the polyarylene sulfide, preferably polyphenylene sulfide, has a particle size (diameter of the particles) D10 of 1 to 15 µm, 3 to 12 µm, or 5 to 9 µm according to ISO 13320-1 in the version valid on the priority date. The particle size D10 is a statistical value derived from a particle size distribution. It describes the particle size below which 10% of the total mass of the particles lies.

[0061] It can be provided that the polyarylene sulfide, preferably polyphenylene sulfide, has a particle size (diameter of the particles) D50 of 5 to 30 µm, 7 to 26 µm, or 8.7 to 24 µm according to ISO 13320-1 in the version valid on the priority date. The particle size D50 is a statistical value derived from a particle size distribution. It describes the particle size below which 50% of the total mass of the particles lies.

[0062] It can be provided that the polyarylene sulfide, preferably polyphenylene sulfide, has a particle size (diameter of the particles) D90 of 10 to 100 µm, 12 to 70 µm, or 15 to 50 µm according to ISO 13320-1 in the version valid on the priority date. The particle size D90 is a statistical value derived from a particle size distribution. It describes the particle size below which 90% of the total mass of the particles lies.

[0063] It may be provided that the polyarylene sulfide, preferably the polyphenylene sulfide, has a maximum particle size (diameter of the particles) of 20 to 200 µm, of 40 to 150 µm or of 43 to 145 µm according to ISO 13320-1 in the version valid on the priority date.

[0064] It may be provided that the polyarylene sulfide, preferably the polyphenylene sulfide, has a density of 0.25 to 0.40 g / ml or of 0.28 to 0.34 g / ml according to ASTM D 1895 in the version valid on the priority date.

[0065] It may be provided that the polyarylene sulfide, preferably the polyphenylene sulfide, has a melt flow rate at 315°C / 5kg of 4000 to 5000 g / 10 min, of 4200 to 4800 g / 10 min or of 4400 to 4600 g / 10 min, for example about 4500 g / 10 min according to ISO 1133-1 in the version valid on the priority date.

[0066] It may be provided that the polyarylene sulfide, preferably the polyphenylene sulfide, has a melting temperature of 250 to 300°C, of ​​270 to 290°C or of 280 to 287°C, according to ISO 11337-1 in the version valid on the priority date.

[0067] It may be provided that the polyarylene sulfide, preferably the polyphenylene sulfide, has a glass transition temperature of 70 to 100°C, of ​​80 to 100°C or of about 90°C, according to ISO 11337-1 in the version valid on the priority date.

[0068] Corresponding polyarylene sulfides with high melt flow rate and / or narrow particle size distribution exhibit excellent properties for coating production, including high-temperature resistance, excellent corrosion protection and good flame retardancy.

[0069] It may be provided that the coating composition comprises polyarylene sulfide, preferably PPS, preferably in an amount of at least 10% by weight, based on the total weight of the coating composition.

[0070] It may be provided that the coating composition further contains at least one filler, preferably a mineral filler, a ceramic filler, or a mixture of two or more thereof, wherein the filler may be a dry lubricant. It may be provided that the filler is selected from the group consisting of graphite, MoS2, boron nitride, Al2O3, BaSO4, iron oxide, or a mixture of two or more thereof.

[0071] The coating composition may further comprise a dry lubricant. The dry lubricant may be graphite, MoS2, boron nitride, or a mixture of two or more thereof. This can further improve the cohesion of sublayers and wear resistance.

[0072] It may be provided that the coating composition comprises the dry lubricant in an amount of 0.1 to 20 wt.%, based on the total weight of the solid contained in the coating composition.

[0073] It may be provided that the graphite has a carbon content of 96 to 98 wt% and an ash content of 2 to 4 wt%.

[0074] It may be provided that the graphite has a grain distribution, min. 99.9%, of less than 60 µm, less than 50 µm or less than 40 µm.

[0075] The graphite can have a particle size (particle diameter) D50 of 1 to 10 µm, 2 to 7 µm, or 3 to 5 µm, measured by laser diffraction. The graphite can have a particle size (particle diameter) D50 of 2 to 15 µm, 5 to 10 µm, or 6 to 8.5 µm, measured by laser diffraction. The graphite can have a particle size (particle diameter) D90 of 10 to 50 µm, 15 to 25 µm, or 15 to 20 µm, measured by laser diffraction.

[0076] It can be provided that the boron nitride has a particle size (diameter of the particles) D50 of 0.5 to 50 µm, of 5 to 20 µm or of 10 to 15 µm, for example about 12 µm measured by laser diffraction according to ASTM B822.

[0077] It may be provided that the boron nitride has a specific surface area (BET) of 1 to 20 m2 / g or of 5 to 10 m2 / g, for example about 7 m2 / g.

[0078] It can be provided that the MoS2 has a particle size (diameter of the particles) D50 of 0.1 µm to 10 µm, of 0.5 µm to 5 µm or of 1 µm to 2 µm.

[0079] It may be provided that the coating composition further comprises an oil or resin.

[0080] The oil may be a silicone oil. The silicone oil may be selected from the group consisting of polyether-functionalized polydimethylsiloxane, polyethersiloxane copolymer, and polydimethylsiloxane.

[0081] It can be provided that the polyether-functionalized polydimethylsiloxane has a kinematic viscosity of 500 to 200 mm2 / s or of 600 to 1400 mm 2 / s according to DIN 51562-1 in the version valid on the priority date.

[0082] It may be provided that the polyether-functionalized polydimethylsiloxane has a refractive index of 1.4500 to 1.4550 according to DIN 51423 in the version valid on the priority date.

[0083] The polyether-functionalized polydimethylsiloxane may be intended to have a cloud point of 37 to 40°C.

[0084] It may be provided that the polyether-functionalized polydimethylsiloxane has a density of 1.00 to 1.10 g / cm3, for example approximately 1.04 g / cm3 according to DIN 51757 in the version valid on the priority date.

[0085] It may be provided that the polyether-functionalized polydimethylsiloxane has a volatility (5g / 2h / 150°C) of 0.0 to 3.0 wt.%.

[0086] It may be provided that the polydimethylsiloxane has a refractive index of 1.400 to 1.410, for example about 1.404.

[0087] It may be provided that the polydimethylsiloxane has a density of 0.9 to 1.0 g / cm 3 or from 0.95 to 0.99 g / cm3, for example about 0.97 g / cm 3 according to DIN 51757 in the version valid on the priority date.

[0088] It may be provided that the polydimethylsiloxane has a flash point of more than 300°C according to ISO 2592 in the version valid on the priority date.

[0089] Alternatively, it may be provided that the polydimethylsiloxane has a flash point of more than 250°C, of ​​270°C to 300°C or of 270°C to 280°C, for example approximately 274°C according to ISO 2719 in the version valid on the priority date.

[0090] It may be provided that the polydimethylsiloxane has an ignition temperature of 400 to 500°C or of 410 to 450°C according to DIN 51794 in the version valid on the priority date.

[0091] It can be provided that the polydimethylsiloxane has a kinematic viscosity of 500 mm2 / s up to 15000 mm2 or 1000 mm 2 / s up to 10000 mm2 at 25°C according to DIN 53019 in the version valid on the priority date.

[0092] It can be provided that the polydimethylsiloxane has a kinematic viscosity of 500 mm 2 / s up to 1500 mm2 or 800 mm 2 / s to 1200 mm2 / s, for example about 1000 mm 2 / s 25°C according to DIN 53019 in the version valid on the priority date.

[0093] Alternatively, the polydimethylsiloxane may have a kinematic viscosity of 5000 mm 2 / s up to 15000 mm2 or 8000 mm 2 / s up to 12000 mm2, for example about 10000 mm 2 / s 25°C according to DIN 53019 in the version valid on the priority date.

[0094] It may be intended that the resin is a silicone resin.

[0095] The silicone resin may have a weight-average molecular weight (Mw) of 2000 to 5000 g / mol, 2000 to 3000 g / mol, for example, approximately 2600 g / mol, as measured by GPC. For the corresponding GPC measurement, 8 mg of the sample was dissolved in 8 mL of 1,2,4-trichlorobenzene at 160°C for 90 min. Then, 200 µL of the sample solution was injected into a high-temperature GPC equipped with an IR5 infrared detector (Polymer Char, Spain) at a flow rate of 0.5 mL / min at 145°C in the column zone and 160°C in the detector zone. The data were processed using GPC One® software (Polymer Char, Spain).

[0096] It may be provided that the silicone resin has an OH content of 3.5 to 7 wt.%, based on the total weight of the silicone resin.

[0097] The silicone resin may be used in the form of flakes and / or granulated flakes and / or a powder for the production of the coating. Alternatively, the silicone resin may be used in the form of an emulsion or a solution.

[0098] It may be provided that the silicone resin has a bulk density of 500 to 700 kg / m3, 530 to 650 kg / m3 or 550 to 610 kg / m3 according to DIN 53466 in the version valid on the priority date.

[0099] It may be provided that the silicone resin has a carbon content of 15 to 20 wt.%, for example about 18 wt.%, based on the total weight of the silicone resin.

[0100] It may be provided that the silicone resin has a melting point of 30 to 60°C, preferably 35 to 55°C, measured by DSC.

[0101] It can be provided that the silicone resin is used in the form of a powder and has a particle size D10 of 5 to 10 µm or 6 to 8 µm, for example approximately 7.2 µm, a particle size D50 of 10 to 30 µm, or 15 to 25 µm, for example approximately 21.8 µm and a particle size D90 of 40 to 80 µm or 60 to 70 µm, for example approximately 58.7 µm, in each case according to ISO 13322 in the version valid on the priority date.

[0102] Alternatively, it can be provided that the silicone resin is used in the form of flakes and has a particle size D10 of 200 to 1000 µm or of 600 to 700 µm, for example about 750 µm, a particle size D50 of 1500 to 2500 µm, or of 2000 to 2200 µm, for example about 2100 µm and a particle size D90 of 2500 to 3500 µm or of 3000 to 3200 µm, for example about 3100 µm, in each case according to ISO 13322 in the version valid on the priority date.

[0103] It may be provided that the coating composition further comprises a pigment, preferably a black pigment. An exemplary corresponding black pigment is copper chromite or black spinel.

[0104] It can be provided that at least the last applied layer is applied with a coating composition that comprises an oil or resin, preferably a silicone oil or a silicone resin, particularly preferably a silicone oil, or consists of the silicone oil. It can be provided that this coating composition, with which the last applied layer is applied, is anhydrous and comprises one or more organic solvents, which is preferably xylene and / or toluene and / or butyl acetate and / or n-butanol. It can be preferred that the solvent is a mixture of xylene, butyl acetate and butanol, furthermore preferably in a weight ratio of 3:(0.5 to 1.5):(0.5 to 1.5), for example 60 xylene / 20 butyl acetate / 20 butanol. Alternatively, it is preferred that the solvent is a mixture of xylene and butyl acetate, more preferably in a weight ratio of 1:(0.5 to 1.5), for example 50 xylene / 50 butyl acetate.This coating composition, with which the final layer is applied, preferably contains silicone oil dissolved in an organic solvent, for example xylene or toluene, in a concentration of 1-10 wt.%, preferably 1-4 wt.%, for example about 1-3 wt.%, based on the total weight of the coating composition with which the final layer is applied. A coating produced in this way surprisingly exhibits non-stick properties just as good as a PTFE coating or a silicone coating, but exhibits much better mechanical and chemical resistance and durability. The improvement in the non-stick effect is permanent and clearly differs from simple oiling, where the oil can be subsequently washed off.

[0105] If the outer layer contains only oil and is baked on, the non-stick properties last much longer than if the surface is only cold-oiled.

[0106] In a further embodiment, the coating composition for applying the final applied layer contains a mixture of silicone oil and resin dissolved in a solvent at a total concentration of 10-40 wt.%, preferably 30-30 wt.%, for example about 23 wt.%, based on the total weight of the layer. In one embodiment, the coating composition for applying the final applied layer contains dissolved in a solvent at a concentration of 1-5 wt.%, preferably 2-4 wt.%, for example about 3 wt.%, based on the total weight of the layer. In a further embodiment, the coating composition for applying the final applied layer contains silicone resin dissolved in a solvent at a total concentration of 10-30 wt.%, preferably 15-25 wt.%, for example about 20 wt.%, based on the total weight of the layer.

[0107] Methyl, phenyl, methylphenyl resin, and mixtures of different resins can be used as silicone resins. The silicone resin may comprise methylpolysiloxane in an amount of 30 to 100 wt.%, based on the total weight of the silicone resin. This final applied layer (cover layer) is preferably clear without pigmentation or contains a maximum of 5% inorganic pigments. In another embodiment, a mixture of water and an organic solvent, for example, isopropanol, is used for the cover layer. Additionally, the cover layer may contain thickeners, defoamers, and wetting agents. The same applies to the dispersions of the underlying thermoplastic layer(s).The baking temperature of this uppermost, thermoplastic-free layer(s) is below that of the underlying layers, preferably below the liquidus temperature of the thermoplastic polymer or the mixture of thermoplastic polymers, but above the glass transition temperature thereof, for example at 230°C.

[0108] The process may further comprise a drying step between application and baking. Drying serves to remove solvents, particularly water and any organic solvents present. Drying may take place at a temperature in the range of 80 to 100 °C (atmospheric pressure). The drying step is optional and may be dispensable, especially when producing thin coatings.

[0109] The process may further comprise a tempering step between drying and baking. The tempering may be carried out for 1 to 30 minutes, for example, for 3 to 5 minutes. Baking the coating composition

[0110] In a further process step, the applied coating composition is baked.

[0111] It may be intended that the firing process takes place at a temperature higher than the liquidus temperature of the thermoplastic polymer. The liquidus temperature is the temperature at which a material is completely molten, i.e., no longer contains any solid components.

[0112] Burning can be done in an oven, by irradiating with infrared or near-infrared radiation, by irradiating with a laser, or a combination of two or more of these. Coated metal sheet

[0113] A second aspect of the present invention relates to a coated metal sheet. The coated metal sheet can be obtained by the inventive method for producing a coated metal sheet, as described in detail herein. The coating produced by the inventive method is largely pore-free and characterized by high uniformity. Surprisingly, it is possible to reshape the metal sheets coated in this way to produce baking pans, plain bearing shells, etc., without the coating flaking or cracking.

[0114] Embodiments of the coated metal sheet mentioned above in connection with the method for producing a coated metal sheet are also embodiments for the coated metal sheet according to the invention.

[0115] The coated metal sheet according to the invention comprises a metal sheet and a coating on at least one side of the metal sheet. The coating can be obtained from the coating composition as described in detail in connection with the process for producing the coated metal sheet.

[0116] The coating may have a layer thickness selected from the group consisting of at least 5 µm, at least 10 µm, at least 15 µm, and at least 20 µm. The coating may have a thickness in a range from 5 to 200 µm, from 50 to 150 µm, preferably from 50 µm to 100 µm.

[0117] The coating thickness can be approximately the same as the thickness of the metal sheet, thus completely and tightly covering the metal sheet. A coating thickness of approximately 50% to 100% of the thickness of the metal sheet is preferred.

[0118] The coating comprises a thermoplastic polymer. The thermoplastic polymer can preferably be one or more of the following, as described in detail in connection with the coating composition, in particular selected from the group consisting of polyaryletherketone (PAEK), in particular the aforementioned embodiments thereof, and a polyarylene sulfide, in particular the aforementioned embodiments thereof, or a mixture of two or more thereof. Further components of the coating are also preferably those, for example, fillers, dry lubricants, etc., as described in detail in connection with the coating composition.

[0119] The coated metal sheet preferably has a contact angle of the coating against water of at least 90°, preferably at least 95°, and particularly preferably between 100° and 120°. For measurement, water droplets are placed on the coating, and the contact angle is optically evaluated using a camera. The measurements are carried out according to DIN EN ISO 19403-2:2020-04 in the version valid on the priority date. With the help of the coating according to the invention, correspondingly very good non-stick properties can be achieved, which can even exceed those of PTFE.

[0120] It can be provided that the coating comprises the thermoplastic polymer in an amount of 60 to 99 wt.%, based on the total weight of the coating.

[0121] It may be provided that the coating comprises solvents in an amount of not more than 90% by weight, based on the total weight of the coating.

[0122] The coating according to the invention, based on thermoplastic polymers selected from polyaryletherketone (PAEK), a polyarylene sulfide, or a mixture of two or more thereof, enables the production of an environmentally friendly product that does not contain critical substances such as PFAS, fluoropolymers, bisphenols, etc., while still exhibiting comparable (or improved) properties to conventional products. In particular, the coatings thus obtained are more durable, mechanically robust, and water vapor-resistant.

[0123] It can be provided that the coating is obtainable by a simple application of an appropriate coating composition followed by suitable treatment (baking, drying, curing, etc.). Alternatively, it can be provided that the coating is obtainable by multiple applications of an appropriate coating composition followed by suitable treatment (baking, drying, curing, etc.), whereby the same or different coating compositions can be used independently for each application in order to obtain different undercoats and achieve the required layer thickness or the desired properties of the coating. It can be provided that the coating is obtainable by multiple applications of an appropriate coating composition followed by suitable treatment (baking, drying, curing, etc.).), with the thickness of the outermost sublayer ranging from 1 nm to 10 µm. The metal sheet is sealed tightly. It is not necessary for all sublayers (sublayers) obtained by multiple coatings to contain the thermoplastic polymer, as long as at least one of the sublayers contains the thermoplastic polymer.

[0124] The sublayers may also be indistinguishable, so that the coating appears as a single layer.

[0125] It can be provided that the coating comprises an inner sub-layer and an outer sub-layer, where - the inner sub-layer is obtainable by applying and baking a coating composition; and - the outer partial layer is obtainable by applying and baking a further coating composition.

[0126] It can be provided that the coating comprises an inner sub-layer and an outer sub-layer, wherein - the inner partial layer preferably comprises polyarylene sulfide in an amount of at least 10 wt.%, preferably at least 20 wt.%, more preferably at least 30 wt.%, further preferably at least 40 wt.%, most preferably at least 50 wt.%, based on the total weight of the inner partial layer; and / or - the outer sub-layer contains a silicone oil and / or a silicone resin and preferably does not comprise a thermoplastic polymer.

[0127] In this case, it can be provided that the inner sub-layer comprises the polyarylene sulfide, preferably polyphenylene sulfide, in an amount of at least 20 wt. %, of at least 30 wt. %, of at least 40 wt. %, or of at least 50 wt. %, based on the total weight of the inner sub-layer. It can be provided that the inner sub-layer consists of the polyarylene sulfide, preferably of polyphenylene sulfide. If the inner sub-layer consists only of polyaryletherketone(s), the surface of an inner sub-layer produced in this way will be disturbed when the outer sub-layer, which contains silicone oil and / or silicone resin, is fired above the liquidus temperature of the thermoplastic. In such a case, "fisheye" effects and uneven flow can be observed. If, on the other hand, the inner sub-layer contains polyarylene sulfide, preferably polyphenylene sulfide, in the aforementioned large amounts, the flow remains surprisingly undisturbed.This applies both to firing above the liquidus temperature of PPS and above the liquidus temperature of PEEK in blends, for example, at 280°C, 300°C, 340°C, 360°C, 400°C, and more. The use of PPS in the inner layer, especially in the aforementioned large quantities, therefore makes the coated metal sheet more flexible and improves the adhesion or impregnation with the silicone oil and / or silicone resin.

[0128] It may be provided that the inner sublayer comprises silicone oil, silicone resin, elastomer, in particular acrylate, polyester, and epoxy resin in an amount of no more than 5 wt.%, preferably in an amount of no more than 1 wt.%, based on the total weight of the inner sublayer. It may be provided that the inner sublayer is free of silicone oil, silicone resin, polyester, and epoxy resin, whereby the term "free of" does not exclude contaminants that cannot be prevented by conventional technical measures.

[0129] It may be provided that the outer partial layer comprises thermoplastic polymer in an amount of no more than 5 wt.%, preferably in an amount of no more than 1 wt.%, based on the total weight of the outer partial layer. It may be provided that the outer partial layer is free of thermoplastic, whereby the term "free of" does not exclude impurities that cannot be prevented by conventional technical measures.

[0130] It can be provided that the outer partial layer comprises at least one further component selected from the group consisting of a pigment, an acrylate, a polyester, an epoxy resin, an additive and a dry lubricant, preferably a dry lubricant as mentioned above.

[0131] It can be provided that the outer partial layer has a thickness of 0.01 µm to 20 µm, for example from 0.01 to 5 µm or from 10 to 20 µm. Coating composition

[0132] A third aspect of the present invention relates to a coating composition, or several different coating compositions, for producing the coated metal sheet by means of the method according to the invention, which is described in detail above. Coating composition for producing an inner sub-layer

[0133] The present invention relates, inter alia, to a coating composition for producing an inner sub-layer of a coated metal sheet, comprising: - 100 parts by weight of a solvent, based on the total weight of the coating composition; and - 5 to 50 parts by weight of a solid mixture, based on the total weight of the coating composition, wherein the solid mixture is dispersed in the solvent mixture; where - the solid mixture comprises 80 to 100 parts by weight of a thermoplastic polymer, wherein the thermoplastic polymer is selected from the group consisting of a polyaryletherketone (PAEK), a polyarylene sulfide, and a mixture of two or more thereof, based on the total weight of the solid mixture; and wherein the coating composition does not comprise a fluoropolymer and preferably does not comprise a bisphenol and / or polyethersulfone.

[0134] The coating composition may be an aqueous dispersion comprising the thermoplastic polymer in the form of dispersed particles.

[0135] The dispersed particles can have an average particle size (particle diameter) D50 of at least 10 µm. It can be provided that the dispersed particles have an average particle diameter selected from the group consisting of at least 15 µm and at least 20 µm. In this context, it can be provided that the particles have an average particle size (particle diameter) D50 of 60 µm or less, 50 µm or less, 40 µm or less, 30 µm or less, or 25 µm or less according to ISO 13320-1 in the version valid on the priority date. The particle size D50 is a statistical value derived from a particle size distribution. It describes the particle size below which 50% of the total mass of the particles lies.

[0136] The dispersion may have a solids content of at least 20 wt.%, based on the total weight of the dispersion.

[0137] The coating composition serves to produce an inner sublayer of a coated metal sheet. The coated metal sheet and the inner sublayer can, in particular, be the coated metal sheet and the inner sublayer described in detail above.

[0138] Embodiments mentioned above with respect to the coated metal sheet, the method for producing the coated metal sheet (particularly in connection with coating compositions described in the method for producing the coated metal sheet) and in the general context of a coating composition, concerning, for example, certain materials, substances, additional components, properties thereof, amounts thereof, etc., are also embodiments for the coating composition for producing an inner sub-layer of a coated metal sheet.

[0139] It may be provided that the solvent contains 30 to 100 parts by weight of water, based on the total weight of the solvent; and the solvent preferably contains 5 to 70 parts by weight of organic solvent, based on the total weight of the solvent.

[0140] It may be provided that the coating composition for producing an inner partial layer of a coated metal sheet comprises organic solvents in an amount of 5 to 50 percent by weight, based on the total weight of the solvent, for example in an amount of 5 to 15 percent by weight, for example about 10 percent by weight.

[0141] It may be provided that the solvent is water and organic solvent in a weight ratio of 20:1 to 1:1, of 15:1 to 5:1, of 12:1 to 8:1, or of 10:1 to 8:1, for example 9:1.

[0142] It may be provided that the organic solvent is selected from the group consisting of isopropanol, ethylene glycol, butyl glycol, propylene glycol, methoxypropanol, n-propoxypropanol, dipropylene glycol methyl ether (DPM) or methoxypropanol acetate and a mixture thereof, for example is isopropanol or a mixture of ethylene glycol and isopropanol, for example in a weight ratio of 2:1 to 1:1.

[0143] Alternatively, the solvent may be an organic solvent or a mixture of two or more organic solvents.

[0144] The solvent may consist of a mixture of two or more solvents, each with a boiling point of more than 100°C under normal pressure. The solvent may consist of a mixture of two solvents, each with a boiling point of more than 100°C under normal pressure.

[0145] The solvent may be an organic solvent. The solvent may have a boiling point in a range of more than 100°C to 200°C, or 110°C to 150°C.

[0146] It can be provided that the solvent is selected from the group consisting of xylene, n-butanol, and butyl acetate. It can be provided that the solvent is a mixture of two solvents selected from the group consisting of xylene, n-butanol, toluene, and butyl acetate. It can be provided that the solvent is a mixture of two solvents, one of the solvents being xylene and the other being n-butanol or butyl acetate, preferably n-butanol, preferably in a xylene:n-butanol weight ratio of 5:1 to 3:1, for example about 4:1.

[0147] It may be provided that the solvent is a mixture of xylene, n-butanol, and butyl acetate, preferably in a weight ratio of 6:(1 to 3):(1 to 3).

[0148] It is intended that the solvent and the solid mixture are contained in a weight ratio of 10:1 to 1:1 or of 10:1 to 3:1 in the coating composition for producing an inner partial layer of a coated metal sheet.

[0149] It may be provided that the solid mixture comprises the thermoplastic polymer in an amount of 80 to 99 parts by weight or 85 to 97 parts by weight or 90 to 95 parts by weight, based on the total weight of the solid mixture.

[0150] It can be provided that the thermoplastic polymer is selected from the group consisting of PEEK, PEK, PPS and a mixture of two or more thereof, It can be provided that the thermoplastic polymer is a mixture of PEEK and PPS, for example in a weight ratio of 2:1 to 1:1 or in a weight ratio of 1:6 to 1:10, preferably 1:8 to 1:10, PEK, or a mixture of two different PEEKs, for example in a weight ratio of 1:1 to 1:3.

[0151] It can be provided that the thermoplastic polymer is a mixture of PEEK and PPS, for example in a weight ratio of 2:1 to 1:1 or in a weight ratio of 1:8 to 1:10, wherein at least one of PEEK and PPS has a particle diameter D so of not more than 20 µm.

[0152] It may be provided that the thermoplastic polymer consists of a PEK.

[0153] It can be provided that the thermoplastic polymer is a mixture of a first PEEK and a second PEEK, for example in a weight ratio of 2:7 to 2:8, wherein at least one of the first PEEK and the second PEEK has a particle diameter D 50 of not more than 20 µm or of not more than 15 µm.

[0154] It may be provided that the solid mixture is in the form of a dispersed fine powder in the solvent.

[0155] It may be provided that the solid mixture further comprises a pigment, preferably a black pigment. It may be provided that the solid mixture comprises the pigment in an amount of 1 to 15 parts by weight or 5 to 10 parts by weight, based on the total weight of the solid mixture, for example in an amount of 4 to 6 parts by weight or 8 to 10 parts by weight.

[0156] It can be provided that the solid mixture further comprises a dry lubricant. It can be provided that the dry lubricant is graphite, MoS2, boron nitride, or a mixture of two or more thereof. It can be provided that the dry lubricant is present in the solid mixture in an amount of 0.2 to 5 parts by weight or 0.5 to 2 parts by weight, based on the total weight of the solid mixture. It can be provided that the dry lubricant is graphite, a mixture of graphite and MoS2, for example in a weight ratio of 2:1 to 1:2, or boron nitride.

[0157] It may be provided that the solvent further comprises a defoamer, a lacquer additive, a wetting agent, a thickener, an adhesion promoter (e.g., zirconate, titanate, or silane), or a mixture of two or more thereof. It may be provided that the solvent further comprises a defoamer, a lacquer additive, a wetting agent, a thickener, and an adhesion promoter. It may be provided that the defoamer, the lacquer additive, the wetting agent, the thickener, and the adhesion promoter (if present) are each present in the solvent in an amount of 0.5 to 2 parts by weight, for example, about 1 part by weight, based on the total weight of the solvent.

[0158] It can be provided that the coating composition for producing an inner partial layer of a coated metal sheet essentially comprises the solvent and the solid mixture. It can be provided that the coating composition for producing an inner partial layer of a coated metal sheet consists of the solvent and the solid mixture.

[0159] It may be provided that the solvent essentially comprises the listed components. It may be provided that the solvent consists of the listed components.

[0160] It may be provided that the solid mixture essentially comprises the listed components. It may be provided that the solid mixture consists of the listed components.

[0161] It can be provided that the coating composition for producing an inner partial layer of a coated metal sheet has a viscosity in a range of 10 to 100 s, 20 to 80 s, or 40 to 60 s, measured with the flow cup according to DIN 53211. Coating composition for producing an outer partial layer (first embodiment)

[0162] The following coating compositions are used to produce an outer sublayer of a coated metal sheet. The coated metal sheet and the outer sublayer can, in particular, be the coated metal sheet and the outer sublayer described in detail above.

[0163] Embodiments mentioned above with respect to the coated metal sheet, the method for producing the coated metal sheet (particularly in connection with coating compositions described in the method for producing the coated metal sheet) and in the general context of a coating composition, concerning, for example, certain materials, substances, additional components, properties thereof, amounts thereof, etc., are also embodiments for the coating composition for producing an outer partial layer of a coated metal sheet.

[0164] In this embodiment, the invention further relates to a coating composition for producing an outer partial layer of a coated metal sheet, comprising: - 40 to 100 parts by weight of a solvent, based on the total weight of the coating composition; and - 5 to 40 parts by weight of a silicone oil, a silicone resin or a mixture of two or more thereof; where - is an organic solvent with a boiling point of more than 100°C under normal pressure or consists of a mixture of two or more solvents each with a boiling point of more than 100°C under normal pressure; wherein the coating composition does not comprise a fluoropolymer and preferably does not comprise isphenol and / or polyethersulfone.

[0165] It may be provided that the solvent consists of a mixture of two solvents each with a boiling point of more than 100°C under normal pressure.

[0166] The solvent may be an organic solvent. The solvent may have a boiling point in a range of more than 100°C to 200°C, or 110°C to 150°C.

[0167] It can be provided that the solvent is selected from the group consisting of xylene, n-butanol, and butyl acetate. It can be provided that the solvent is a mixture of two solvents selected from the group consisting of xylene, n-butanol, toluene, and butyl acetate. It can be provided that the solvent is a mixture of two solvents, one of the solvents being xylene and the other being n-butanol or butyl acetate, preferably n-butanol, preferably in a xylene:n-butanol weight ratio of 5:1 to 3:1, for example about 4:1.

[0168] It may be provided that the coating composition comprises the solvent in an amount of 45 to 85 parts by weight or 50 to 80 parts by weight, based on the total weight of the coating composition, for example from 55 to 65 parts by weight, from 75 to 85 parts by weight, or from 45 to 55 parts by weight.

[0169] It may be provided that the coating composition for producing an outer partial layer of a coated metal sheet comprises the silicone oil, the silicone resin or the mixture of two or more thereof in an amount of 10 to 35 parts by weight or 15 to 33 parts by weight, based on the total weight of the coating composition, for example in an amount of 15 to 25 parts by weight, 20 to 25 parts by weight, or 22 to 24 parts by weight.

[0170] It can be provided that the coating composition comprises a silicone oil and a silicone resin, for example in a weight ratio of silicone oil:silicone resin of 1:1 to 1:15, 1:2 to 1:12, 1:4 to 1:8, or 1:5 to 1:7.

[0171] It may be provided that the coating composition comprises the silicone oil in an amount of 1 to 12 parts by weight or 1 to 5 parts by weight, based on the total weight of the coating composition, for example in an amount of 2 to 4 parts by weight.

[0172] It may be provided that the coating composition comprises the silicone resin in an amount of 8 to 32 parts by weight or 10 to 30 parts by weight, based on the total weight of the coating composition, for example in an amount of 15 to 25 parts by weight or 18 to 22 parts by weight.

[0173] It may be provided that the coating composition for producing an outer partial layer of a coated metal sheet further contains a thickener, preferably in an amount of 1 to 15 parts by weight or 5 to 10 parts by weight, based on the total weight of the coating composition. It may be provided that the thickener is an acrylate. It may be provided that the thickener is an acrylate resin, preferably a thermoplastic acrylate resin.

[0174] It may be provided that the coating composition for producing an outer partial layer of a coated metal sheet further comprises a wetting agent. It may be provided that the coating composition comprises the wetting agent in an amount of 1 to 5 parts by weight, 1 to 3 parts by weight, or 1.5 to 2.5 parts by weight, based on the total weight of the coating composition.

[0175] The coating composition may further comprise a dry lubricant. The dry lubricant may be graphite. The dry lubricant may be present in the coating composition in an amount of 0.2 to 5 parts by weight or 1 to 2 parts by weight, based on the total weight of the coating composition.

[0176] The coating composition may further comprise a pigment, preferably a black pigment. The coating composition may comprise the pigment in an amount of 1 to 15 parts by weight or 3 to 10 parts by weight, based on the total weight of the coating composition, for example in an amount of 2 to 4 parts by weight, 4 to 6 parts by weight, or 8 to 10 parts by weight.

[0177] It can be provided that the coating composition for producing an outer partial layer of a coated metal sheet has a viscosity in a range of 10 to 30 s. Coating composition for producing an outer partial layer (alternative embodiment)

[0178] The following coating compositions are used to produce an outer sublayer of a coated metal sheet. The coated metal sheet and the outer sublayer can, in particular, be the coated metal sheet and the outer sublayer described in detail above.

[0179] Embodiments mentioned above with respect to the coated metal sheet, the method for producing the coated metal sheet (particularly in connection with coating compositions described in the method for producing the coated metal sheet) and in the general context of a coating composition, concerning, for example, certain materials, substances, additional components, properties thereof, amounts thereof, etc., are also embodiments for the coating composition for producing an outer partial layer of a coated metal sheet.

[0180] In this alternative embodiment, the invention relates to a coating composition for producing an outer partial layer of a coated metal sheet, comprising: - 100 parts by weight of a solvent, based on the total weight of the coating composition; and - 5 to 50 parts by weight of a solid mixture, based on the total weight of the coating composition, wherein the solid mixture is dispersed in the solvent mixture; where - the solvent is an organic solvent with a boiling point of more than 100°C under normal pressure or consists of a mixture of two or more solvents each with a boiling point of more than 100°C under normal pressure; - the solid mixture contains 70 to 100 parts by weight of a thermoplastic polymer, wherein the thermoplastic polymer is selected from the group consisting of a polyaryletherketone (PAEK), a polyarylene sulfide, a polyimide, and a mixture of two or more thereof, based on the total weight of the solid mixture; and wherein the coating composition does not comprise a fluoropolymer and preferably does not comprise a bisphenol and / or polyethersulfone.

[0181] It may be provided that the coating composition comprises the solvent in an amount of 45 to 85 parts by weight or 50 to 80 parts by weight, based on the total weight of the coating composition, for example from 55 to 65 parts by weight, from 75 to 85 parts by weight, or from 45 to 55 parts by weight.

[0182] The solvent may consist of a mixture of two or more solvents, each with a boiling point of more than 100°C under normal pressure. The solvent may consist of a mixture of two solvents, each with a boiling point of more than 100°C under normal pressure.

[0183] The solvent may be an organic solvent. The solvent may have a boiling point in a range of more than 100°C to 200°C, or 110°C to 150°C.

[0184] It may be provided that the solvent is selected from the group consisting of xylene, n-butanol, and butyl acetate. It may be provided that the solvent is a mixture of two solvents selected from the group consisting of xylene, n-butanol, toluene, and butyl acetate. It may be provided that the solvent is a mixture of xylene, n-butanol, and butyl acetate, preferably in a weight ratio of 6:(1 to 3):(1 to 3).

[0185] It may be provided that the solid mixture comprises the thermoplastic polymer in an amount of 80 to 99 parts by weight or 90 to 95 parts by weight, based on the total weight of the solid mixture.

[0186] It may be provided that the thermoplastic polymer consists of a PEK.

[0187] It can be provided that the thermoplastic polymer is a mixture of a first PEEK and a second PEEK, for example in a weight ratio of 2:7 to 2:8, wherein at least one of the first PEEK and the second PEEK has a particle diameter D50 of not more than 20 µm or not more than 15 µm.

[0188] It may be provided that the solid mixture is in the form of a dispersed fine powder in the solvent.

[0189] It may be provided that the solid mixture further comprises a pigment, preferably a black pigment. It may be provided that the solid mixture comprises the pigment in an amount of 1 to 15 parts by weight or 5 to 10 parts by weight, based on the total weight of the solid mixture, for example in an amount of 4 to 6 parts by weight or 8 to 10 parts by weight.

[0190] It can be provided that the solid mixture further comprises a dry lubricant. It can be provided that the dry lubricant is graphite, MoS2, boron nitride, or a mixture of two or more thereof. It can be provided that the dry lubricant is present in the solid mixture in an amount of 0.2 to 5 parts by weight or 0.5 to 2 parts by weight, based on the total weight of the solid mixture. It can be provided that the dry lubricant is graphite, a mixture of graphite and MoS2, for example in a weight ratio of 2:1 to 1:2, or boron nitride.

[0191] It may be provided that the solvent further comprises a defoamer, a paint additive, a wetting agent, a thickener, an adhesion promoter, or a mixture of two or more thereof. It may be provided that the solvent further comprises a defoamer, a paint additive, a wetting agent, a thickener, and an adhesion promoter. It may be provided that the defoamer, the paint additive, the wetting agent, the thickener, and the adhesion promoter (if present) are each present in the solvent in an amount of 0.5 to 2 parts by weight, for example, about 1 part by weight, based on the total weight of the solvent.

[0192] It can be provided that the coating composition for producing an outer partial layer of a coated metal sheet has a viscosity in a range of 10 to 100 s, 20 to 80 s or 40 to 60 s. Use of coated metal sheet

[0193] A third aspect of the present invention relates to the use of the coated metal sheet as described in detail above as a component of a cooking or baking utensil, preferably a pan or pot, or as a grate. The above-mentioned embodiments of the coated metal sheet, the method according to the invention, and the coating composition according to the invention are also embodiments for the use according to the invention.

[0194] According to the invention, the term "cooking and baking accessories" encompasses any object shaped to hold food and subsequently cook and bake it. Therefore, in addition to pans, the above term also encompasses baking trays, baking pans, etc., as well as grill trays, grill containers, grill racks, etc. General definitions

[0195] Unless expressly stated otherwise, a feature stated in the singular (a, an...) also includes the plural. For example, if it is stated that the composition according to the invention contains a dye, this also includes the case where the composition contains a mixture of several dyes.

[0196] Unless expressly stated otherwise, terms such as "comprising", "containing", etc. include the meanings "essentially comprising", "essentially containing", or "consisting of". Substantially comprising here means comprising at least 70% by weight, comprising at least 80% by weight, comprising at least 90% by weight, comprising at least 95% by weight, comprising at least 98% by weight, or comprising at least 99% by weight, based on the total weight of the article, composition, etc. comprising the corresponding component.

[0197] The amounts given in percent add up to a total amount of 100% by weight and thus give the total amount.

[0198] Tests have shown that the properties can be specifically adjusted by selecting the thermoplastic polymers (the first layer(s), the amount of dry lubricant, and the selected thicknesses of the non-metallic sheet metal and the layer thicknesses of the first and, if applicable, the second layer). The more PEEK or even PEK the base layer contains, the more wear-resistant and temperature-resistant the coating is.

[0199] The sheets produced in this way were suitable for the production of all kinds of bearing parts, such as bearing shells, bearing cages, etc. Non-stick coated sheets could be used for the production of baking trays, pots, pans, etc., but also as high-quality conveyor belts, for example in plastics and food production.

[0200] The features of the invention disclosed in the above description and in the claims may be essential both individually and in any combination for the realization of the invention in its various embodiments. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited non-patent literature

[0000] DIN EN ISO 2808:2019-12

[0019] DIN EN ISO 2360

[0019] DIN 1319, Part 1 and Part 3

[0019] ISO 11443

[0049] ISO 13322-1:2014

[0050] DIN EN ISO 19403-2:2020-04

[0119]

Claims

[1] A coated metal sheet obtainable by a process for producing a coated metal sheet comprising the following steps: (i) providing a metal sheet; (ii) applying a coating composition to at least one side of the metal sheet; and (iii) baking the coating composition; wherein - the coating composition comprises a thermoplastic polymer; - the coating composition is a dispersion comprising the thermoplastic polymer in the form of dispersed particles; - the dispersed particles have an average particle diameter of at least 10 µm; - the coating composition does not comprise a fluorinated compound; and - the application of the coating composition comprises dip coating, knife coating, pouring, roll coating or a combination of two or more thereof. [2] The coated metal sheet according to claim 1, wherein the application is carried out by the coil coating process. [3] The coated metal sheet according to claim 1 or 2, wherein the thermoplastic polymer is selected from the group consisting of polyaryletherketone (PAEK), a polyarylene sulfide, and a mixture of two or more thereof. [4] The coated metal sheet according to any one of the preceding claims, wherein the polyaryletherketone (PAEK) is a polyaryletheretherketone (PEEK), a polyaryletherketoneketone (PEKK), a polyaryletherketoneetherketoneketone (PEKEKK), a copolymer of two or more thereof, or a mixture of two or more thereof. [5] The coated metal sheet according to any one of the preceding claims, wherein the polyarylene sulfide is a polyphenylene sulfide. [6] The coated metal sheet according to any one of the preceding claims, wherein the dispersed particles have an average particle diameter selected from the group consisting of at least 15 µm, at least 20 µm, at least 25 µm and at least 30 µm. [7] The coated metal sheet according to any one of the preceding claims, wherein the coating composition further contains at least one filler, preferably a mineral filler, a ceramic filler or a mixture of two or more thereof. [8] Coated metal sheet obtainable by a process according to any one of the preceding claims, comprising - a metal sheet; and - a coating on at least one side of the metal sheet. [9] Coated metal sheet according to claim 8, wherein the coating has a layer thickness selected from the group consisting of at least 5 µm, at least 10 µm, at least 15 µm and at least 20 µm. [10] Coated metal sheet according to claim 8 or 9, wherein the coating comprises an inner sub-layer and an outer sub-layer, wherein - the inner sub-layer is obtainable by applying and baking the coating composition; and - the outer partial layer is obtainable by applying and baking the further coating composition. [11] A coating composition for producing an inner sub-layer of a coated metal sheet, comprising: - 100 parts by weight of a solvent, based on the total weight of the coating composition; and - 5 to 50 parts by weight of a solid mixture, based on the total weight of the coating composition, wherein the solid mixture is dispersed in the solvent mixture; wherein - the solid mixture comprises 80 to 100 parts by weight of a thermoplastic polymer, wherein the thermoplastic polymer is selected from the group consisting of a polyaryletherketone (PAEK), a polyarylene sulfide, and a mixture of two or more thereof, based on the total weight of the solid mixture; and wherein the coating composition does not comprise a fluoropolymer and preferably does not comprise a bisphenol and / or polyethersulfone. [12] A coating composition for producing an outer sub-layer of a coated metal sheet, comprising: - 40 to 100 parts by weight of a solvent, based on the total weight of the coating composition; and - 5 to 40 parts by weight of a silicone oil, a silicone resin or a mixture of two or more thereof; where - is an organic solvent having a boiling point of more than 100°C under normal pressure or consists of a mixture of two or more solvents each having a boiling point of more than 100°C under normal pressure; wherein the coating composition does not comprise a fluoropolymer and preferably does not comprise bisphenol and / or polyethersulfone. [13] A coating composition for producing an outer sub-layer of a coated metal sheet, comprising: - 100 parts by weight of a solvent, based on the total weight of the coating composition; and - 5 to 50 parts by weight of a solid mixture, based on the total weight of the coating composition, wherein the solid mixture is dispersed in the solvent mixture; wherein - the solvent is an organic solvent with a boiling point of more than 100°C under normal pressure or consists of a mixture of two or more solvents each with a boiling point of more than 100°C under normal pressure; - the solid mixture contains 70 to 100 parts by weight of a thermoplastic polymer, wherein the thermoplastic polymer is selected from the group consisting of a polyaryletherketone (PAEK), a polyarylene sulfide, a polyimide, and a mixture of two or more thereof, based on the total weight of the solid mixture; and wherein the coating composition does not comprise a fluoropolymer and preferably does not comprise a bisphenol and / or polyethersulfone. [14] A component of a cooking or baking accessory, preferably a pan or a pot, or as a component of a conveyor belt comprising the coated metal sheet according to one of claims 1 to 11.