Pes-based non-fluorinated coating

Abstract

The invention relates to a coated heating element (1) for a household article, comprising a metal substrate (2) coated on at least one surface (2a) with a coating (3) free of fluorocarbon resin and comprising at least the following layers and in this order starting from the metal substrate (2): (3a) a primer layer consisting of polyethersulfone (PES) or a mixture of polyethersulfone (PES) and one or more silicone resins, and optionally: - one or more fillers and / or - one or more additives, and / or - one or more colorants; (3b) one or more intermediate layers consisting of polyethersulfone (PES) or a mixture of polyethersulfone (PES) and one or more silicone resins, and optionally: - one or more fillers and / or - one or more additives, and / or - one or more colorants; (3c) a finishing layer consisting of polyethersulfone (PES), or consisting of a mixture of polyethersulfone (PES) and one or more silicone resins, or consisting of one or more silicone resins, and optionally: - one or more fillers and / or - one or more additives, and / or - one or more colorants; it being understood that the layer (3a), the layer (3c) and at least one of the layers (3b) are different.

Description

[0001]Non-fluorinated coating based on PES The invention applies to the field of non-stick coatings for household items, which are heated or can be heated, in particular for cookware and electrical cooking appliances. Cookware coated with PTFE (polytetrafluoroethylene) is popular on the market because it allows food to be cooked without, or with little, added fat and is easy to maintain. However, an inherent weakness of these coatings is their low mechanical strength, especially when hot. Another inherent weakness of PTFE is its ductility, which results in coatings that are easy to mark, scratch, or wear with metal utensils (spatulas, forks, spoons, blender sticks, etc.). To overcome this, many technical solutions have been proposed, which consist of reinforcing the coating with hard fillers or by interposing hard sub-layers of inorganic or organic type.In the case of primers reinforced with hard organic or inorganic fillers, significant improvements in abrasion resistance are indeed observed, but impacts to metal are also observed when cooking foods such as pork chops or when using metal spatulas. In the case of hard inorganic bases such as those made from enamel or metal oxides, abrasion resistance is further improved and the impact problem is limited without being eliminated. Organic polymer undercoats are also known. These undercoats can indeed considerably reduce the appearance of scratches or even eliminate them. This strategy is therefore very interesting.The polymers used are very often thermoplastic polymers with high thermal resistance and a high melting point, such as polyaryletherketone, particularly oxy-1,4-phenylenephenylene-oxy-1,4-phenylene-carbonyl-1,4-phenylene or PEEK, or phenylene sulfides. Pure silicone resins are described as relatively non-stick and resistant to temperatures above 220-230°C. However, they are considered to have poor adhesion to the substrate. Conversely, silicone-polyester resins are widely used in molding because they are non-stick while adhering to the substrate and compatible with stamping processes. However, they degrade at temperatures above 230°C.Indeed, the temperature range of use of cookware is between 50 and 250°C and it is not surprising to rise to temperatures of 300°C or even 350°C in the case of articles with induction bases. Their use is therefore not compatible with the temperatures of use in the field of cookware. The present invention deals with the technical problem of improving the non-stick properties of a coating with high thermo-mechanical properties as well as, where appropriate, its suitability for drawing. The present invention also deals with the technical problem of replacement solutions for coatings based on fluororesin of the PTFE type.The present invention provides an alternative to predominantly PTFE-based coatings in order to obtain good resistance to mechanical wear of the coatings, in particular by kitchen utensils for culinary articles and thus improve the durability of their mechanical resistance, in particular when hot and / or their cleanability, in order to extend the life of the article. DEFINITIONSBy the term "layer", it is necessary to understand within the meaning of the present invention a continuous or discontinuous layer. A continuous layer (or also called monolithic layer) is a single whole forming a total flat area completely covering the surface on which it is placed. A discontinuous layer (or non-monolithic layer) may comprise several parts which are not thus a single whole.The term "base coat", "primer coat", "bonding coat" or "bonding primer" refers to all the layers from the first layer applied directly to the substrate (it is preferable that this layer adheres well to the substrate and provides all its mechanical properties to the coating: hardness, scratch resistance) to the last layer before the first intermediate or decorative layer or the finishing layer if the coating does not include an intermediate layer. The first layer of the coating is a primer coat. The term "intermediate layer" refers to the layers inserted between the primary layer(s) and the finishing layer(s). The intermediate layer(s) may be "decorations" or "decorative layers". The intermediate layer(s) is / are not intended to be in contact with food.The term "finish coat" or "finish" means one or more continuous surface layers applied after the intermediate layer(s) if the coating comprises one or more intermediate layer(s) or after the primary layer(s). The last layer of the coating is a finishing layer. Usually, at least the last finishing layer, or even all finishing layers, is / are transparent to allow visibility of the underlying layers, in particular when the underlying layers are decorative layers. The finishing layer(s) protect the underlying layers from mechanical attack and give the coating its non-stick properties. Preferably, in the case of a cookware or electrical cooking appliance, the last finishing layer is intended to be in contact with food.The term "decor" or "decorative layer" means one or more continuous or discontinuous layers comprising a pigment composition. The decor may be in the form of one or more patterns, in one or more colors. A decor is clearly visible to the user with the naked eye and at a conventional distance for using the household item. The term "overlapping layers" means partially or completely superimposed layers. These layers may be in the form of partially overlapping patterns, for example concentric discs. The term "adjacent layers" means non-superimposed layers. These layers may be in the form of identical or different non-superimposed patterns, preferably uniformly distributed.The term "temperature reference pigment composition" means a composition comprising a pigment which, at a given temperature, makes it possible to indicate to the user that the optimum use temperature has been reached. This indication is made by comparing the colours of the thermochromic pigment composition and the temperature reference pigment composition. Either the optimum use temperature is reached when the colours are identical, or the optimum use temperature is reached when the colours are visually very different. The "temperature reference pigment composition" may comprise a pigment which has: - the same colour as the thermochromic pigment composition, at the optimum use temperature, * or because this pigment has the same colour at room temperature as the thermochromic pigment composition at the optimum use temperature. ,and does not change color with temperature, * either because this pigment has a color at room temperature that is different from that of the thermochromic pigment composition which evolves to the same color as the thermochromic pigment composition at the optimal use temperature, - a color very different from that of the thermochromic pigment composition at the optimal use temperature, whether or not this pigment changes color with the evolution of the temperature. The optimal use temperature can be reached when the color of the temperature reference pigment composition corresponds to a color indicated in the user guide of the household article comprising the coating of the invention or to a color indicated on a color scale provided to the user with said article. The temperature reference pigment composition is thermochromic or thermostable.The temperature reference pigment composition may be, for example, a cooking temperature reference pigment composition or an indication of the risk of overheating. The expression "thermochromic semiconductor" is understood to mean, within the meaning of the present invention, a mineral or organic compound which exhibits a reversible change in coloration upon an increase in temperature. The progressive and reversible thermochromic nature of these semiconductor compounds is linked to the reduction in the width of the forbidden band of the semiconductor due to the expansion of the material. Indeed, the periodicity of the network of anions and cations leads to the grouping of energy levels into energy bands. The filled energy band with the highest energy is called the valence band and the empty energy band with the lowest energy is called the conduction band. Between these two bands, there is a forbidden band called the gap.The color of a semiconductor material may come from the presence of a charge transfer which corresponds to the passage of an electron either from a valence band to a conduction band on the same atom, or commonly from the orbital of an anion to the orbital of a cation (interatomic photonic absorption). In the fields of application envisaged for the present invention, the optimal conditions are reached when the coating reaches a temperature suitable for cooking food, preferably between 100 and 250°C. By "thermochromic pigment or pigmentary composition", it is necessary to understand, within the meaning of the present invention, a pigment or a pigmentary composition which changes color depending on the temperature in a given temperature range, this change being reversible. This change of color is visible to the user with the naked eye and at a conventional operating distance.The term "thermostable pigment" means a pigment which does not exhibit a change in color when subjected to an increase in temperature in a given temperature range or which exhibits a change in hue when subjected to an increase in temperature in a given temperature range so small that it is not visible to the user with the naked eye and at a conventional operating distance. Preferably, the thermostable pigments exhibit a color difference ΔE* between 25°C and 200°C of less than 10, ΔE* being defined by the CIE1976 formula in the colorimetric space. CIELAB : L1*, a1* and b1* characterizing the L*a*b values ​​of said compound at room temperature L2*, a2* and b2* characterizing the L*a*b values ​​of said compound at 200°C. By "the colors are identical" is meant indistinguishable by the user with the naked eye and at a conventional operating distance. By the expression "cooking article", it is necessary to understand within the meaning of the present invention an object intended to cook and to be heated by an external heating system such as frying pans, saucepans, sauté pans, woks, barbecue grills. A cooking article is capable of transmitting the heat energy provided by this external heating system to a material or food in contact with said article. By the expression "electric cooking appliance", it is necessary to understand within the meaning of the present invention a heating object having its own heating system such as an electric crepe maker, an electric raclette appliance, an electric fondue appliance, an electric grill, a griddleelectric, electric cooker, bread maker, electric pressure cooking appliance. The term "coating" means all the layers adhering to the metal substrate and covering this substrate. The coating according to the invention obtained is advantageously solid, "solid" means the characteristic of a cohesive material insoluble in water, in usual solvents, in food components such as aqueous or fatty mixtures, even if the material may have great hardness or great flexibility such as an elastomer. In the present invention, the % by weight are expressed in dry weight, i.e. without solvent. SUMMARY OF THE INVENTION A first subject of the invention relates to a coated heating element (1) for household article, comprising a metal substrate (2) coated on at least one face (2a) with a coating (3) free of fluorocarbon resin and comprising at least the following layers and in this order from the metal substrate (2): (3a) aprimer layer consisting of polyethersulfone (PES) or a mixture of polyethersulfone (PES) and one or more silicone resins, and optionally:- one or more fillers and / or- one or more additives, and / or- one or more coloring agents (3b) one or more intermediate layer(s) consisting of polyethersulfone (PES) or a mixture of polyethersulfone (PES) and one or more silicone resins, andoptionally:- one or more fillers, and / or- one or more additives, and / or- one or more coloring agents (3c) topcoat consisting of polyethersulfone (PES), or consisting of a mixture of polyethersulfone (PES) and one or more silicone resins, or consisting of one or more silicone resins, and optionally:- of one or more fillers and / or- of one or more additives, and / or- of one or more coloring agent(s);it being understood that the layer (3a), the layer (3c) and at least one of the layers (3b) aredifferent.Another subject of the invention relates to a method of manufacturing a household article comprising a heating element coated (1) with a coating (3) according to the invention, characterized by the following steps:a) a step of providing a metal substrate (2) in the form of a substantially flat metal substrate comprising two opposite faces or a support (2) of convex or hollow shape defining a concave inner face (21) and a convex outer face (22); b) where appropriate, when a metal substrate in the form of a substantially flat metal substrate is provided during step (a), a step of shaping said substrate to give it the shape of a support (2) of convex or hollow shape defining a concave inner face (21) and a convex outer face (22), said step (b) being carried out either before step (a), or before step (d) of producing the layers (3a), (3b) and (3c) of the coating (3), or after step (f) of bakingand before the optional step (g) of producing a layer (3d) or after step (g);c) optionally, a step of treating at least one face (2a) of the metal substrate (2), to obtain a treated face (2a) promoting the adhesion of a primer layer (3a) to the support (2);d) a step of applying the layers (3a), (3b) and (3c) of the coating (3);e) optionally a drying step between 50°C and 150°C after applying each of the layers (3a) (3b) and (3c); f) optionally a step of baking the element obtained in step d) or e) at a temperature between 250°C and 420°C;g) optionally, a step of applying the layer (3d) to the element obtained in step d), e) or f);h) optionally a step of baking the element obtained in step g) at a temperature between 250°C and 420°C. Another subject of the invention relates to a household article comprising a coated heating element (1) according to the invention or capable of being coatedobtained according to the method of the invention. FIGURES [Fig.1]: diagram of heating element according to the invention with layer (3b) is continuous and covers the entire layer (3a) [Fig.2]: diagram of heating element according to the invention with layer (3b) does not cover the entire layer (3a) and forms a decoration [Fig.3]: diagram of heating element according to the invention with layer (3b) consists of two decorations (i) and (j) [Fig.4]: diagram of distribution of the patterns. 4A = adjacent non-overlapping patterns. 4B = partially overlapping patterns. 4C = overlapping patterns. [Fig.5]: diagram of a cooking article according to the invention [Fig.6]: diagram of an electrical cooking appliance according to the invention DETAILED DESCRIPTION A first subject of the invention relates to a coated heating element (1) for a household article, comprising a metal substrate (2) coated on at least one face (2a) with a coating (3) free of fluorocarbon resin and comprising at least the following layers and inthis order from the metal substrate (2): (3a) a primer layer consisting of polyethersulfone (PES), or a mixture of polyethersulfone (PES) and one or more silicone resins, and optionally: - one or more fillers and / or - one or more additives, and / or - one or more coloring agents (3b) one or more intermediate layers consisting of polyethersulfone (PES) or a mixture of polyethersulfone (PES) and one or more silicone resins, and optionally: - one or more fillers, and / or - one or more additives, and / or - one or more coloring agents (3c) finishing layer consisting of polyethersulfone (PES), or a mixture of polyethersulfone (PES) and one or more silicone resins, or consisting of one or more silicone resins, and optionally:- one or more filler(s) and / or- one or more additive(s), and / or- one or more coloring agent(s);it being understood that the layer (3a),the layer (3c) and at least one of the layers (3b) are different. Advantageously, the layers (3a), (3b) and (3c) form a coating (3) which covers the metal substrate (2). This coating (3) has non-stick properties and forms a non-stick coating. Advantageously, the layer (3a) is in contact by one of its faces with the metal substrate (2) by its face (2a). When the household item is a culinary item or an electrical cooking appliance, the coated face (2a) of the metal substrate forms a cooking face. In other words, the coating (3) according to the invention is then intended to be in contact with food. Advantageously, the finishing layer (3c) is then in contact by one of its faces with food and thus forms a cooking face (5). The coating (3) according to the invention does not comprise fluorocarbon resin, also called fluorinated polymer or fluoropolymer. In other words, said coating (3) is free of fluorocarbon resin.Thus, the coating (3) does not comprise or emit perfluoroalkyl and polyfluoroalkyl compounds. Advantageously, the thickness of each of the coating layers (3a), (3b) and (3c) is from 5 µm to 15 µm. At least one intermediate layer (3b) is present in the coating (3) according to the invention. The at least one intermediate layer (3b) is different from at least one primer layer (3a) and from at least one finishing layer (3c). More preferably, in this case, all the intermediate layers (3b) are different from the primer layer(s) (3a) and from the finishing layer(s) (3c).PESAdvantageously, the PES is micronized. The PES may have a d50 ranging from 5 µm to 20 µm, preferably from 8 µm to 18 µm. The term "D50" is understood to mean, within the meaning of the present invention, the maximum dimension that 50% of the particles have by number. According to embodiments, the PES content in the primer layer (3a) is lower than the content ofPES in layer(s)(3b). In this case, advantageously, the PES content increases from the primer layer (3a) to the finishing layer (3c). Thus, advantageously, the PES content of the primer layer (3a) represents from 50% to less than 75% by weight of the primer layer (3a), preferably from 55% to 70%. Advantageously, the PES content of the intermediate layer (3b) represents from 75 to less than 85% by weight of the intermediate layer (3b), preferably from 75% to 80%. Advantageously, the PES content of the finishing layer (3c) represents from 85% to 98% by weight of the finishing layer (3c), preferably from 85% to 95%. In these embodiments, advantageously, the layers (3a) to (3c) are made of polyethersulfone (PES) and optionally: - one or more fillers and / or- one or more additive(s), and / or- one or more coloring agent(s).In these embodiments, advantageously, the layers (3a) to (3c) areconsisting of polyethersulfone (PES) and:- one or more fillers;- one or more additives;- and one or more coloring agents.In these embodiments, advantageously, the filler content decreases from the primer layer (3a) to the finishing layer (3c). According to other embodiments, the PES content in the primer layer (3a) is higher than the PES content in the layer(s) (3b). In this case, advantageously, the PES content decreases from the primer layer (3a) to the finishing layer (3c). Thus, advantageously, the PES of the primer layer (3a) represents from 25% to 30% by weight of the primer layer. Advantageously, the PES of the intermediate layer (3b) represents from 20% to less than 25% by weight of the intermediate layer. Advantageously, the PES of the finishing layer (3c) represents from 10% to less than 20% by weight of the finishing layer, preferably from 15% to less than 20%. In these embodimentsembodiment, advantageously, the layers (3a) to (3c) consist of polyethersulfone (PES) and silicone resins, and optionally: - one or more fillers and / or - one or more additives, and / or - one or more coloring agents. In these embodiments, advantageously, the layers (3a) to (3c) consist of polyethersulfone (PES) and silicone resins and: - one or more fillers; - one or more additives; - and one or more coloring agents. In these embodiments, advantageously, the silicone resin content increases from the primer layer (3a) to the finishing layer (3c). In these embodiments, advantageously, the PES content decreases from the primer layer (3a) to the finishing layer (3c) and the silicone content increases from the primer layer (3a) to the finishing layer (3c). In these embodiments, advantageously, the (PES+silicone resin) content of the layers (3a),(3b) and (3c) ranges from 40% to 90% or from 50% to 90%, preferably from 60% to 90%, even more preferably from 70% to 90% by weight of each layer. In these embodiments, the presence of silicone resins and PES makes it possible to confer both the non-stick character of the coating as well as its ability to be drawn in the case where the coated heating element is shaped after deposition of the coating (3). These embodiments are thus particularly suitable in the case of shaping the heating element to give it a convex shape such as for a frying pan for example. According to other embodiments, in particular when the coated heating element is shaped by stamping after deposition of the coating (3) and the coating (3) is subjected to high stresses during this stamping step, the layer (3c) may be made of polyethersulfone (PES) and silicone resins and:- one or more fillers;- one or moreadditive(s);- and one or more coloring agent(s).the PES content being between 60% and 80% by weight of the layer (3c), the silicone resin content being between 5% and 30% by weight of the layer (3c) and the (PES+silicone resin) content being between 70% and 98%, preferably between 80% and 98%, even more preferably between 90% and 98% by weight of the layer (3c).In this case, the layers (3a) and (3b) may consist of PES and:- one or more filler(s);- one or more additive(s);- and one or more coloring agent(s).Advantageously, the PES of the primer layer (3a) represents from 50% to less than 75% by weight of the primer layer, preferably from 55% to 70%. %. Advantageously, the PES of the intermediate layer (3b) represents from 75 to less than 85% by weight of the intermediate layer, preferably from 75% to 80%. The high PES content of the layer (3c) as well as of the layers (3a) and (3b) makes it possible to ensuregood drawability under high stress. The presence of silicone resin in the layer (3c) also ensures good non-stick properties. These embodiments are thus particularly suitable in the case of shaping the heating element to give it a hollow shape for a saucepan, for example. FILLERSAdvantageously, the primer layer(s) (3a) and / or the intermediate layer(s) (3b) and / or the layer(s) (3c) comprises / comprise one or more fillers. According to this embodiment, the primer layer(s) (3a) and / or the intermediate layer(s) (3b) and / or the layer(s) (3c) comprises / comprise less than 40%, preferably less than 30%, by weight of fillers relative to the total weight of said layer, preferably between 5 and 25% by weight. The fillers within the meaning of the invention make it possible to provide mechanical reinforcement and can also provide hydrophobicity properties, while improving themechanical strength and thermal conductivity of the coating. The fillers do not only have the function of providing color to the coating, but can contribute to it. Advantageously, the filler(s) is / are chosen from the group consisting of ceramic fillers (SiO2, etc.) and / or mineral and / or metallic fillers (Al2O3, TiO2, etc.) and / or silicas and / or diamond particles. Preferably, the filler(s) is / are chosen from the group consisting of metal oxides, metal carbides, metal oxynitrides, metal nitrides, and mixtures thereof. Advantageously, said metal is a transition metal, such as at least one of the elements chosen from B, Ni, Ti, Zr or Hf. More preferably, the filler(s) is / are chosen from the group consisting of:- fillers for reinforcement: organic or inorganic hard fillers; the inorganic hard fillers are preferably particles of silicon carbide or alumina or zirconiaor graphite, or ceramics, or carbonate, or hydrated alumina, aluminum trihydroxide or one or more metal oxide(s), graphite, graphene;- other fillers for reinforcement chosen from metal oxides: silica, micas, lamellar fillers, clays such as montmorillonite, sepiolite, gypsite, kaolinite and laponite, zinc dioxide, quartz, and zirconium phosphate, alumina, zirconia, zinc oxide, copper oxide, iron oxide;- fillers chosen from reinforcing fibers: glass or carbon or aramid fiber;- conductive fillers comprising a transition metal carbide and / or a transition metal nitride: characterized in that the transition metal is at least one of the elements chosen from B, Ni, Ti, Zr or Hf, for example: Boron Nitride cubic, diamond particles, metallic particles; - lamellar fillers which can provide lubricating properties, such as for exampleclays, graphene or graphite. Among the fillers in combination with silicone resins, the preferred fillers are:- reinforcing fillers: silica or carbonates with filler rates of at least 10-15% / wt and up to 60% / wt,- alumina, hydrated alumina, aluminum trihydroxide,- silica (precipitated or pyrogenic) with a d50 < 0.1 µm and a BET specific surface area > 30 m2 / g and preferably between 30 and 500 m2 / g,- or mixture of quartz and silica, diatomaceous earth or ground quartz, titanium, mica, talc, kaolin, barium sulfate, slaked lime, zinc oxide, expanded vermiculite, unexpanded vermiculite, calcium carbonate etc. More preferably, the filler(s) is / are chosen from the group consisting of alumina, silicon carbide, tungsten carbide, boron nitride, quartz, and mixtures thereof. Advantageously, the fillers present in the primer layer(s) (3a) or the intermediate layer(s)(3b) are inorganic hard fillers, preferably metal oxides, carbides, nitrides, preferably alumina, silicon carbides or fumed silica. Some inorganic hard fillers such as silicon carbide, in addition to their mechanical reinforcement performance, also have the advantage of being conductive fillers and therefore provide excellent thermal conductivity. The addition of this type of filler makes it possible to improve the culinary rendering with better diffusion of heat from the metal substrate to the food in contact with the coating. Advantageously, the average diameter d50 of the fillers is between 0.1 and 50 µm, advantageously still between 5 and 15 µm. Advantageously, the proportion of fillers in a layer is between 0.5 and 30% by dry weight relative to the total weight of said layer after cooking, preferably between 5 and 20%. Advantageously, the proportion of fillers in the layer (3a) is greater than 20%by weight, preferably greater than 30% by weight, relative to the total weight of said layer. Advantageously, the proportion of fillers in layer (3c) is less than 10% by weight relative to the total weight of said layer. Advantageously, the proportion of fillers in layers (3a), (3b) and (3c) may be identical or different. Advantageously, the nature of the fillers in layers (3a), (3b) and (3c) may be identical or different. ADDITIVES Advantageously, the primer layer(s) (3a) and / or the intermediate layer(s) (3b) and / or the layer(s) (3c) comprises / comprise one or more additives. Advantageously, the additive(s) is / are chosen from the group consisting of anti-foaming agents, dispersing agents, wetting agents, thickeners, pH adjusters, reactive silicone oils. Said anti-foaming agent(s) are preferably chosen from the group consisting of mineral oils, diols, hydrocarbons, glycerides,oxyrane, emulsified fatty acids. The surfactant(s) is(are) preferably chosen from the group consisting of glycol ether, ethoxylated alcohol excluding alkyl phenol ethoxylates (APE), gemini surfactants. The dispersing agent(s) is(are) preferably chosen from the group consisting of anionic dispersants such as fatty acid derivatives. Said thickeners are preferably chosen from the group consisting of acrylic-based or polyurethane-based copolymer, cellulose, fumed silica. Said pH adjusters are preferably chosen from the group consisting of Bronsted bases: ammonia, amines (triethylamine, triethanolamine, etc.), hydroxides (soda, potash, etc.), carbonates. Advantageously, the primer layer(s) (3a) and the intermediate layer(s) (3b) comprise one or more acrylic resin(s). The acrylic resin(s) is / are advantageously chosen from the group consisting ofpolymers resulting from an emulsion polymerization of different monomers with other acrylic-based monomers. Advantageously, the primer layer(s) (3a) or the intermediate layer(s) (3b) comprises / comprise one or more surfactants. Advantageously, the primer layer(s) (3a) or the intermediate layer(s) (3b) further comprises / comprise one or more anti-foaming agents. Advantageously, the primer layer(s) (3a) or the intermediate layer(s) (3b) further comprises / comprise water and / or one or more solvents, preferably unlabeled, for example propionamide, or alcoholic, for example dipropylene glycol butyl ether (DPNB). Other solvents are possible if necessary, such as N-formylmorpholine (NFM), N-Methyl Imidazole (NMI), N-ButylPyrrolidone (NBP), dimethyl sulfoxide (DMSO), Propylene Glycol (PPG), Diethylene glycol. Advantageously, the finishing layer (3c) comprises an oilsilicone.Advantageously, the silicone oil represents from 1 to 5% by weight of the finishing layer (3c), preferably from 2% to 4%.COLOURING AGENTS Advantageously, the primer layer(s) (3a) or the intermediate layer(s) (3b) comprises / comprise one or more colouring agent(s). Advantageously, the primer layer(s) (3a) or the intermediate layer(s) (3b) comprises / comprise less than 30%, preferably less than 20%, by weight of one or more colouring agent(s) of the total weight of said layer. Advantageously, the colouring agent(s) is / are chosen from the group consisting of thermochromic pigments, thermostable pigments, glitter, preferably hologram glitter, and mixtures thereof. Advantageously, the proportion of coloring agents in layers (3a), (3b) and (3c) is between 0.5 and 50% by dry weight relative to the total weight of said layer after cooking. Advantageously, the proportion of coloring agentsin layers (3a) and (3b) ranges from 10% to 40% by weight relative to the total weight of said layer. Advantageously, the proportion of coloring agents in layer (3c), when present, is less than 10% by weight relative to the total weight of said layer. Advantageously, the proportion of coloring agents in layers (3a), (3b) and (3c) may be identical or different. Advantageously, the nature of the coloring agents in layers (3a), (3b) and (3c) may be identical or different. Advantageously, layer (3c) is transparent. In this case, if it comprises coloring agents, these coloring agents are flakes. Thermochromic pigments Preferably, the thermochromic pigment(s) is / are chosen from the group consisting of Bi2O3, Fe2O3, V2O5, WO3, CeO2, In2O3, Y 1,84 That 0,16 You 1,84 V 0,16 O 1,84 , AgI, (Bi 1-x HAS x )(V 1- y M y)O4with -x is equal to 0 or x is from 0.001 to 0.999,- y is equal to 0 or y is from 0.001 to 0.999,- A and M are selected from the group consisting of nitrogen, phosphorus, an alkali metal, an alkaline earth metal, a transition metal, a poor metal, a metalloid or a lanthanide, -A and M are different from each other.Knowing that A and M are different from each other, when:- A is an alkali metal, it can be selected from Li, Na, K, Rb, Cs,- M is an alkali metal, it can be selected from Li, Na, K, Rb, Cs,- A is an alkaline earth metal, it can be selected from Be, Mg, Ca, Sr, Ba,- M is an alkaline earth metal, it can be selected from Be, Mg, Ca, Sr, Ba,- A is a transition metal, it can be chosen from Sc, Ti Cr, Mn, Fe, Co, Ni, Cu, Y, Zr,Nb, Mo, Ru, Rh, Pd, Ag, Ta, W, Ir,- M is a transition metal, it can be chosen from Sc, Ti Cr, Mn, Fe, Co, Ni, Cu, Y, Zr,Nb, Mo, Ru, Rh, Pd, Ag, Ta, W, Ir,- A is a poor metal,it can be chosen from Al, Zn, Ga, In, Sn,- M is a poor metal, it can be chosen from Al, Zn, Ga, In, Sn,- A is a metalloid, it can be chosen from B, Si, Ge, Sb,- M is a metalloid, it can be chosen from B, Si, Ge, Sb,- A is a lanthanide, it can be chosen from La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho,Er, Tm, Yb, Lu,- M is a lanthanide, it can be chosen from La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho,Er, Tm, Yb, Lu. Preferably, A and M different from each other are B and / or Mg. Preferably, the pigment (Bi, 1-x HAS x )(V 1-y M y )O4has a monoclinic scheelite crystallographic form at room temperature. Preferably, x and y are 0, i.e. the pigment (Bi 1-x HAS x )(V 1-y M y)O4 is Bismuth Vanadate (BiVO4). Advantageously, a BiVO4 with a monoclinic scheelite crystallographic structure at room temperature is used. Bismuth Vanadate is a yellow inorganic compound, with the formula BiVO4, widely used for its coloristic properties and its lack of toxicity. Registered in the Colour Index International database as QI Pigment Yellow 184, it is notably marketed by the companies Heubach (Vanadur®), BASF (Sicopal®), FERRO (Lysopac) and Bruchsaler Farbenfabrik (Brufasol®).Thermostable pigments Preferably, the thermostable pigment(s) is / are selected from the group consisting of:- Yellow pigment of titanium rutile type,- Yellow pigment derived from bismuth, for example selected from stabilized bismuth vanadates (Py184)- Red pigment, for example selected from perylene red (for example PR149, PR178 and PR224), iron oxide,- Orange pigment of bismuth oxyhalides type (PO85),- Orange pigment of bismuth vanadate (PO86)- Orange pigment of zinc tin titanium (PO82)- Orange pigment of cerium sulfide (PO75; PO78)- Orange yellow pigment of antimony titanium chromium rutile type (PBr24)- Orange yellow pigment of zinc tin rutile type (Py216)- Niobium tin zinc sulfide orange yellow pigment (Py227)- Orange yellow pigment of double oxides of tin and niobium- Co3(PO4)2. - LiCoPO4 - CoAl2O4 - Cr2O3 - TiO2- Black pigment PBk28 (Copper chromite black spinel) - and mixtures thereof. Decorations According to one embodiment, the layer(s) (3b) is(are) continuous and covers the entire layer (3a) (see Figure 1). According to another embodiment, the layer(s) (3b) does(do) not cover the entire layer (3a) and forms(form) at least one decoration (see Figure 2). Advantageously, the layer(s) (3b) compose(s) several decorations, one (i) comprising one or more thermochromic pigment(s) and the other (j) comprising at least one temperature reference pigment composition (see Figure 3). According to one embodiment, each of the two decorations (i) and (j) is in the form of adjacent non-overlapping patterns. For example, each decoration is represented by different geometric patterns distributed evenly over the entire surface and alternating with each other (see Figure 4A).According to another embodiment, the two decorations (i) and (j) are partially overlapping. For example, each decoration is represented by different geometric patterns distributed uniformly over the entire surface and partially overlapping (see Figure 4B). Preferably, the two decorations (i) and (j) are overlapping, either because one of the two decorations is a continuous layer and the other decoration covers it in the form of patterns, or because the two decorations (i) and (j) are in the form of overlapping patterns (see Figure 4C). Flakes The flakes that can be used in the context of the present invention can be independently chosen from mica flakes, coated or not, silica flakes, coated or not, aluminum flakes, coated or not, iron oxide flakes, coated or not. Mica or silica flakes coated with titanium dioxide.The flakes usable in the context of the present invention can be treated to give a particular color effect. Advantageously, the flake(s) is / are particles chosen from the group consisting of particles of mica, aluminum, mica coated with titanium dioxide or mixtures thereof. Hologram flakes Advantageously, the flake(s) is / are hologram flakes, i.e. a mixture of magnetizable particles and non-magnetizable particles. The magnetizable particles can advantageously be particles comprising at least one ferromagnetic metal. These magnetizable particles can be of a homogeneous nature, i.e. made of the same material, or of a composite nature, i.e. these magnetizable particles have a core-shell structure, in which the ferromagnetic metal is found in the core and / or in the shell of said particles.Examples of composite magnetizable particles include mica flakes coated with iron oxide Fe2O3 or stainless steel fibers coated with a sol-gel material, as protection against corrosion during the coating application steps, or plastic flakes coated with iron oxide Fe2O3, or flakes whose core is made of ferromagnetic metal and the shell is formed of a plastic material or a sol-gel material. According to one embodiment, a portion of said magnetizable particles is oriented so as to form a three-dimensional decoration. Advantageously, the mixture of magnetizable particles and non-magnetizable particles represents between 1% and 5% by weight of the weight of the layer, preferably between 2% and 3% by weight.Advantageously, the percentage of non-magnetizable particles in the mixture of magnetizable particles and non-magnetizable particles is between 15% and 40% by weight relative to the total weight of the mixture of magnetizable particles and non-magnetizable particles. Advantageously, the magnetizable particles have a dimension D50 of less than or equal to 23 µm. The term "D50" is understood to mean, for the purposes of the present invention, the maximum dimension that 50% of the particles have by number. Advantageously, the non-magnetizable particles have a dimension D90 of between 20% and 250% of the dimension D90 of the magnetizable particles. The term "D90" is understood to mean, for the purposes of the present invention, the maximum dimension that 90% of the particles have by number. Advantageously, the magnetizable particles and / or the non-magnetizable particles are surface-colored.Advantageously, the non-magnetizable particles consist of mica, aluminum, or mica coated with titanium dioxide. Advantageously, the magnetizable particles consist of iron, iron oxide, iron-coated aluminum, or iron-coated mica, the iron being in ferritic form. SILICONE RESINSIn the text of the description, the expression "silicone resin" is used interchangeably to refer to the silicone before its crosslinking or after its crosslinking. In the text of the description, the expression "silicone" designates an organopolysiloxane material. Crosslinking is the step which makes it possible to transform the silicone into an insoluble material, for example by polyaddition, polycondensation or dehydrogenation. Crosslinking is carried out from precursors which are generally silicone oils or resins, which crosslink to obtain a three-dimensional network forming a material called silicone resin, in the description.This crosslinking can be done by thermal activation, or chemical activation using a catalyst, such as platinum. The silicone resins can be obtained from precursors, advantageously soluble in a solvent or in emulsion in water, such as oils or crosslinkable resins, in particular chosen from: a silicone hydride, a silicone oil resin comprising at least one vinyl group (-CH=CH2), a silicone or silicone-polyester resin (copolymer) comprising at least one alkoxy group, for example methoxy or ethoxy, and / or a silicone or silicone-polyester resin (copolymer) comprising at least one alkoxy group, in particular ethoxy, or a hydroxy group and mixtures thereof. These precursors have the capacity to crosslink in order to obtain a silicone resin which is characterized by its insolubility and its substantially solid form.Advantageously, these precursors are polymeric or oligomeric, either in the form of silicone oils with a variable degree of branching, or in the form of silicone resins with a variable degree of pre-crosslinking or copolymers of silicone resins such as silicone-polyester, silicone-alkyd, silicone-polyurethane, silicone-epoxy resins, or in the form of a mixture of silicone oils, silicone resins and copolymers of silicone resins. The silicon atoms may be substituted by alkyl (in particular methyl) or aryl (in particular phenyl) groups or mixtures thereof. The oils or resins preferably comprise one or more (2, 3 or more) hydroxy or alkoxy (in particular methoxy, ethoxy, butoxy) functional groups as substituents of silicon atoms.Advantageously, the silicone resin(s), obtained after crosslinking their precursors, i.e. crosslinked, is / are chosen from the group consisting of methyl silicone and / or phenyl silicone and / or methyl-phenyl-silicone resins, methyl silicone-polyester resin (copolymers), phenyl silicone-polyester resin (copolymers), methyl-phenyl silicone-polyester resin (copolymers), silicone-alkyd resin (copolymers), modified silicone resin and mixtures thereof. Advantageously, the silicone resin(s) is / are chosen from the group consisting of methyl silicone and / or phenyl silicone and / or methyl-phenyl-silicone resins, methyl silicone-polyester resin (copolymers), phenyl silicone-polyester resin (copolymers), methyl-phenyl silicone-polyester resin (copolymers), silicone-alkyd resin (copolymers), modified silicone resin and mixtures thereof.Silicone resins can be obtained from precursors, in particular chosen from: a silicone hydride, a silicone resin comprising at least one vinyl group (-CH=CH2), a silicone-polyester resin (copolymer) comprising at least one methoxy group, and / or a silicone-polyester resin (copolymer) comprising at least one ethoxy group, and mixtures thereof. The silicone resin forms a network which can be made up of a combination of 4 simple organosiloxane units called M, D, T and Q depending on the degree of substitution by oxygen of the silicon atom, as described in the following table, where R is an organic substituent described below. The organopolysiloxane material or polymer is obtained by crosslinking from precursors which can be monomeric or polymeric, or intermediately which can be oligomeric.The organopolysiloxane polymer can also be obtained from a mixture of these different kinds of precursors. When the network contains a higher number of T and Q units than D, the crosslinking density is higher. The distribution between the M, D, T and Q units depends on the chemical structure of the precursors, in particular on this M, D, T, Q distribution within the precursors. The polymeric precursors are organopolysiloxanes. These macromolecules are formed of M, D, T, and / or Q units as described in the table, where R is independently an alkyl group, in particular methyl, or aryl, in particular phenyl, different natures of R can be present on the same macromolecule. Organopolysiloxanes can be either linear or slightly branched (majority of D groups), or branched or highly branched (majority of T and Q groups).Linear or slightly branched organopolysiloxanes are generally liquid, more or less viscous at room temperature, and are called silicone oils. Branched or highly branched (pre-crosslinked) organopolysiloxanes form a network at the level of the individual macromolecule and are called silicone resins. At room temperature, the resins are substantially in solid form, or in liquid form, provided in particular that they have a fairly low molecular weight, in the form of a solution in a solvent or in the form of an aqueous emulsion. They can be copolymerized with organic polymers or oligomers not containing silicon, chosen in particular from polyesters, acrylics, alkyds, polyurethanes, epoxy resins. When the crosslinking is a hydrolysis-polycondensation: it is carried out thanks to the reactive hydroxy or alkoxy functions, in particular methoxy, ethoxy or butoxy, present on the organopolysiloxane.When the crosslinking is a polyaddition (or hydrosilylation): it is carried out by reaction between the reactive vinyl functions (-CH=CH2) present on one of the organopolysiloxanes and the reactive silyl hydride functions (Si-H) present on the other organopolysiloxane mixed with the first. All these reactive functions are present on each organopolysiloxane in number of at least one and can be present in number of 2, 3, or more… as much as the molecular structure allows. Silicone oils containing at least one reactive function are called “reactive oils”. The reactive functions can be found either at the end of the macromolecular chain (termination), or distributed over the chain. Silicone-polyester resins in particular have silicone / polyester mass ratios of, for example, 90 / 10, 80 / 20, 70 / 30, 60 / 40, 50 / 50, 40 / 50, 30 / 70, 20 / 80, 10 / 90, advantageously between 80 / 20 and 50 / 50.Linear PDMS silicone oils, pure or pre-emulsified in water, are characterized firstly by their molecular mass, which is a direct increasing function of the viscosity of the pure oil. They are then characterized by the presence or absence of reactive functions, for example hydroxyls on the silicon atoms (silanol), their number and their location on the molecular chain. For example, reactive oils with viscosities between 50 and 20,000 mPa.s, and in particular between 300 and 5,000 mPa.s, can be used, having at least one reactive function, preferably at least 2, which can be placed at the end of the chain.Polymer precursors reacting by polyaddition may include, for example, polymethylhydrosiloxane, vinylmethylsiloxane, polydimethylsiloxane (PDMS) terminated with vinyl, in particular linear, diphenylsiloxane-dimethylsiloxane copolymers with vinyl termination, hydride terminated polydimethylsiloxanes, hydride terminated polyphenylmethylsiloxanes, cyclic vinylmethylsiloxane, vinyl-MQ resin, trimethylsilyl terminated polymethylhydrosiloxane, copolymer of methylhydrosiloxane and trimethylsiloxane terminated dimethylsiloxane, hydride of MQ resin, and the like, as well as combinations thereof.Polymeric precursors reacting by hydrolysis-polycondensation, whether silicone resins or silicone oils, may include, for example, poly(methylsilsesquioxanes), poly(propylsilsesquioxanes), poly(phenylsilsesquioxanes), polydimethylsiloxane (PDMS), trimethylsilyl-terminated polydimethylsiloxane (PDMS), hydroxyl-terminated polydimethylsiloxane (PDMS), silanol-terminated polydimethylsiloxane (PDMS), silanol-terminated polyphenylsiloxane (PDMS), silanol-terminated diphenylsiloxane-dimethylsiloxane copolymer, poly(2-acetoxyethylsilsesquioxanes), organo-modified alkoxysilanes and their oligomers, and all similar macromolecules and their mixtures.The organopolysiloxane material or polymer may also be obtained by crosslinking a mixture of one or more monomeric precursors and one or more polymeric precursors as described above, as well as one or more oligomeric precursors which may be linear, branched or cyclic. These oligomeric precursors have a lower molecular weight than the polymeric precursors. Polymeric and / or oligomeric precursors comprising a number of reactive functions as described above greater than 2, advantageously much greater than 2, may be added to the mixture as a “co-binder” in order to promote a high crosslinking density of the organopolysiloxane polymer finally obtained.Monomeric, oligomeric and / or polymeric precursors, in particular silicone resins, copolymerized or not with an organic polymer, act as a polymeric binder in order to obtain the solid organopolysiloxane polymer combined with the thermoplastics of each layer. Organopolysiloxane precursors of the silicone oil type can be considered as additives if they are added in small quantities (generally between 0.1 and 5% in dry weight) in the entire formula of a layer, independently of the other components for the formation of the solid organopolysiloxane polymer.Crosslinking may require a catalyst:- In the case of crosslinking organopolysiloxanes by hydrolysis-polycondensation, the formula may include a metal catalyst, such as, for example, metal complexes based on platinum, tin, zinc, zirconium and cerium, in particular platinum-cyclovinylmethyl-silxane complexes, tin ethylhexanoate, zinc ethylhexanoate, zirconium ethylhexanoate, cerium ethylhexanoate, and dibutyl tin laurate.- In the case of crosslinking organopolysiloxanes by hydrosylilation, the addition of a catalyst may be necessary: ​​this may be, for example, platinum or a suitable platinum-based catalyst such as the Karstedt catalyst or the Ashbys catalyst. A crosslinking agent, for example, carrying Si-H bonds, may be present. OTHER ARCHITECTURES According to a particular embodiment, the coating comprises two intermediate layers (3b), including at least one decorative layer.Advantageously, the layer(s) (3b) compose several decorations, one (i) comprising one or more thermochromic pigment(s) and the other (j) comprising at least one temperature reference pigment composition. Preferably, the intermediate layer(s) (3b) only partially cover the base layer (3a). According to one embodiment, the finishing layer (3c) consists of one or more silicone resins, and optionally: - one or more filler(s) and / or - one or more additive(s), and / or - one or more coloring agent(s).According to one embodiment, the coated heating element (1) further comprises a layer (3d) which will be the last layer of the coating (3) when it is present, consisting of: - an elastomer silicone obtained from at least one organopolysiloxane bearing reactive vinyl functions (-CH=CH2) and at least one other organopolysiloxane bearing reactive silyl hydride functions (Si-H) or reactive thiol functions (SH); and optionally: - one or more thermoplastic polymers, and / or - one or more additive(s), and / or - one or more coloring agent(s). The organopolysiloxanes bearing reactive functions of the layer (3d) are precursors which react by a crosslinking which is a polyaddition.This crosslinking is carried out by reaction between the reactive vinyl functions (-CH=CH2) present on one of the organopolysiloxanes and the reactive silyl hydride functions (Si-H) or the reactive thiol functions (Si-H) present on the other organopolysiloxane mixed with the first. This crosslinking can be carried out by thermal activation, activation by UV irradiation or chemical activation. Preferably, this crosslinking is carried out in the presence of a catalyst or a radical initiator. According to one embodiment, when the crosslinking is carried out by reaction between the reactive vinyl functions (-CH=CH2) present on one of the organopolysiloxanes and the reactive silyl hydride functions (Si-H) present on the other organopolysiloxane mixed with the first, the reaction is preferably carried out in the presence of a metal catalyst, for example platinum or a suitable platinum-based catalyst such as the Karstedt catalyst or the Ashbys catalyst.According to one embodiment, when the crosslinking is carried out by reaction between the vinyl reactive functions (-CH=CH2) present on one of the organopolysiloxanes and the thiol reactive functions (SH) present on the other organopolysiloxane mixed with the first, the reaction is preferably carried out in the presence of a radical initiator. According to one embodiment, it may be a thermally activated radical initiator such as, for example, 2,2′-Azobis(2-methylpropionamidine) dihydrochloride (or V50). According to one embodiment, it may be a radical initiator activated by UV irradiation such as, for example, Irgacure®651 (2,2-Dimethoxy-2-phenylacetophenone). Advantageously, the organopolysiloxanes carrying reactive functions of layer (3c) are silicone oils.Reactive functions are present on each organopolysiloxane in the number of at least one and can be present in the number of 2, 3, or more… as much as the molecular structure allows. Silicone oils containing at least one reactive function are called “reactive oils”. The reactive functions can be found either at the end of the macromolecular chain (termination), or distributed over the chain.Advantageously, the thermoplastic polymer(s) is / are chosen from the group consisting of polyethersulfone (PES), polyphenylene ether sulfone (PPSU), polyamideimide (PAI), polyimide (PI), poly(phenylene oxide) (PPO), poly(arylene sulfide) (PAS), polyetherimide (PEI), and polybenzymidazole (PBI), liquid crystal polymers (LCP), polyphenylene sulfide (PPS), polyarylether ketone (PAEK) including polyether ketone (PEK), polyether ether ketone (PEEK), polyether ketone ketone (PEKK), polyether ether ketone ketone (PEEKK), polyether ketone ether ketone ketone (PEKEKK) and mixtures thereof. Examples of heterocyclic thermoplastic polymers suitable according to the invention are polyetherimides (PEI), polyimides (PI), polyamideimides (PAI) and polybenzymidazole (PBI), or mixtures thereof.Advantageously, the polyaryletherketone(s) (PAEK) is (are) chosen from the group consisting of: polyetherketones (PEK), polyetheretherketone (PEEK), polyetherketoneketones (PEKK), polyetheretherketoneketones (PEEKK) and polyetherketoneetherketoneketones (PEKEKK), particularly preferably is (are) PEEK. The additives and coloring agents are as described above. Advantageously, the thickness of the finishing layer (3d) is from 0.1 µm to 10 µm, preferably from 0.5 µm to 5 µm, particularly preferably from 1 µm to 2 µm. METALLIC SUBSTRATE Advantageously, said metallic substrate (2), also called support, is a substrate made of aluminum, stainless steel, cast iron or aluminum, iron, titanium or copper. By aluminum in the sense of the present invention is meant a metal consisting of 100% aluminum or an aluminum alloy.Advantageously, the metal substrate (2) is an aluminum substrate, a stainless steel substrate or a multilayer metal substrate. The metal substrate (2) may be a two-layer or three-layer substrate, these multilayers being able to be obtained for example by co-lamination, by hot diffusion under load (solid state bonding) or by hot or cold impact bonding. Preferably, the metal substrate (2) comprises alternating layers of metal and / or metal alloy. According to one embodiment, the metal substrate (2) is an aluminum alloy substrate, a stainless steel substrate or a multilayer metal substrate whose face (2a) is made of aluminum alloy or stainless steel. Preferably, the metal substrate (2) is an aluminum substrate. Advantageously, the thickness of the metal substrate (2) is between 0.5 mm and. 10 mm.Advantageously, the face (2a) of the metal substrate (2) has previously undergone a surface treatment to improve the adhesion of the coating to said substrate. According to one embodiment, the surface of the face (2a) of the metal substrate (2) has undergone a surface treatment, said surface treatment being a chemical attack, brushing, hydration, sandblasting, shot blasting, a physicochemical treatment of the plasma or corona or laser type, a chemical activation or a combination of these different techniques. Advantageously, the face of the substrate (2a) on which the coating (3) according to the invention will be applied can be treated so as to increase its specific surface area; for an aluminum substrate, this treatment can be done by anodization (creation of a tubular alumina structure), by chemical attack, by sandblasting, by brushing, by shot blasting or by adding material by means of a technology such as thermal spraying (flame,plasma or arc spray). The other metal substrates can also be polished, sandblasted, brushed, microblasted or have material added by means of a technology such as thermal projection (flame, plasma or arc spray). As metal substrates that can be used in the present invention, mention may advantageously be made of anodized or non-anodized aluminum substrates, optionally polished, brushed, sandblasted, shot-blasted or microblasted, anodized or non-anodized aluminum alloy substrates, optionally polished, brushed, sandblasted or microblasted, steel substrates, optionally polished, brushed, sandblasted, shot-blasted or microblasted, stainless steel substrates, optionally polished, brushed, sandblasted or microblasted, cast steel, aluminum or iron substrates, and copper substrates, optionally hammered or polished. Advantageously, the substrate can be chosen from substrates comprising ferritic stainless steel / aluminum / austenitic stainless steel layers,substrates comprising stainless steel / aluminum / copper / aluminum / austenitic stainless steel layers, cast aluminum, aluminum or aluminum alloy caps lined with a stainless steel outer base, metal co-laminated substrates, for example two-layer co-laminated substrates comprising a stainless steel layer (for example intended to constitute the inner face of the article) and a layer of aluminum or aluminum alloy, anodized or not (for example intended to constitute the outer face of the article). Advantageously,the average arithmetic roughness Ra of the surface of the face (2a) of the metal substrate (2) is greater than or equal to 1 µm. The average arithmetic roughness Ra is measured using a roughness meter according to ISO 4287. Ra represents the arithmetic mean of the deviations from the mean. The surface topography can be studied in particular with a profilometer with a probe equipped with a fine stylus equipped with a diamond tip, or with an optical metrology device such as Altisurf®, in which a chromatic confocal sensor allows a contactless measurement. The study of this surface topography makes it possible to define the average arithmetic roughness Ra. METHOD The invention also relates to a method for manufacturing a heating element coated (1) with a coating (3) for a household article according to the invention, characterized by the following steps: a) a step of providing a metal substrate (2) comprising two opposite faces; c) optionally,a step of treating at least one face (2a) of the metal substrate (2), to obtain a treated face (2a) promoting the adhesion of a primer layer (3a) on the support (2); d) a step of applying the layers (3a), (3b) and (3c) of the coating (3); e) optionally a drying step between 50°C and 150°C after application of each of the layers (3a) (3b) and (3c); f) optionally a step of baking the element obtained in step d) or e) at a temperature between 250°C and 420°C g) optionally, a step of applying the layer (3d) on the element obtained in step d),e) or f); h) optionally a step of baking the element obtained in step g) at a temperature between 250°C and 420°C. The invention also relates to a method for manufacturing a household article comprising a heating element coated (1) with a coating (3) according to the invention, characterized by the following steps: a) a step of providing a metal substrate (2) in the form of a substantially flat metal substrate comprising two opposite faces or a support (2) of convex or hollow shape defining a concave inner face (21) and a convex outer face (22); b) where appropriate, when a metal substrate in the form of a substantially flat metal substrate is provided during step (a), a step of shaping said substrate to give it the shape of a support (2) of convex or hollow shape defining a concave inner face (21) and a convex outer face (22), said step (b) being carried out either before step (a),either before step (d) of producing the layers (3a), (3b) and (3c) of the coating (3), or after step (f) of baking and before the optional step (g) of producing the layer (3d) or after step (g);c) optionally, a step of treating at least one face (2a) of the metal substrate (2), to obtain a treated face (2a) promoting the adhesion of a primer layer (3a) to the support (2);d) a step of applying the layers (3a), (3b) and (3c) of the coating (3); e) optionally a drying step between 50°C and 150°C after application of each of the layers (3a) (3b) and (3c);f) optionally a step of baking the element obtained in step d) or e) at a temperature between 250°C and 420°C g) optionally, a step of applying the layer (3d) to the element obtained in step d), e) or f)h) optionally a step of baking the element obtained in step g) at a temperature between 250°C and 420°C.Advantageously,during step d), the layer(s) (3a), (3b) and (3c) is / are applied by pad printing, electrostatic powdering, spray spraying, screen printing, roller application or digital printing, preferably by spraying. Advantageously, the spraying is carried out in a solvent-based or aqueous phase. Advantageously, during step g), the layer (3d) is applied by electrostatic powdering, spraying, screen printing, spray gun, doctor blade, coating cylinder, brush, roller application or digital printing, preferably by spraying. According to an advantageous arrangement of the invention, the finishing layer (3d) is applied to the coated support at a deposition rate of less than or equal to 5 g / m, 2 , preferably between 0.1 and 2.5 g / m 2 , even more preferably between 0.2 and 2 g / m 2Advantageously, the method according to the invention comprises a step of crosslinking g') of the finishing layer (3d) subsequent to or simultaneous with step g). According to a variant, the crosslinking of the finishing layer (3d) can generally be activated by heat treatment, at a temperature between 50 and 400°C, preferably between 50 and 300°C, obviously taking into account the maximum resistance of the support to heat. Advantageously, the crosslinking (g') of the finishing layer (3d) is carried out at a temperature of 300°C for a period of 10 min. Advantageously, the higher the crosslinking temperature, the shorter the crosslinking time. According to one embodiment, the crosslinking step g') does not require heat treatment, in particular because the support is hot at the time of step g).Advantageously, the steps of the method according to the invention make it possible to coat the metal support (2) with a coating (3) formed by the layers (3a), (3b) and (3c), optionally (3d). Generally, these layers are wet when they are applied. By wet layer, it is understood within the meaning of the present invention that the layer comprises all or part of its solvents. The shaping is also called stamping. When the shaping step precedes the application d) of the coating, the coating is preferably carried out by spraying. When this shaping step is subsequent to the application d) of the coating, the coating is preferably carried out by screen printing or by roller. ARTICLE The invention also relates to a household article comprising a heating element coated according to the invention or capable of being obtained according to the method of the invention.According to one embodiment, this household item is a cooking item or an electrical cooking appliance and the layer (3c) forms a cooking face. In this case, the layer (3c) is advantageously transparent. In this case, the coloring agent of the layer (3c) is advantageously glitter. Advantageously, the cooking item (100) according to the invention is chosen from the group consisting of saucepan, frying pan, skillets or pots for fondue or raclette, stewpot, wok, sauté pan, crepe maker, grill, griddle, pot, casserole dish, cooker or bread machine bowl, cooking mold, molds and plates for pastry, barbecue plates and grills, preparation bowls. According to one embodiment, the cooking item (100) comprises a heating face (6) intended to be placed in contact with an external heating source, the heating face (6) being opposite the cooking face (5) intended to be placed in contact with the food during cooking.According to embodiments, the layer (3c) or the layer (3d), when present, is intended to be placed in contact with a heating source. The culinary article according to the present invention may in particular be a culinary article of which one of the two opposite faces of the substrate is an inner face, possibly concave, intended to be arranged on the side of food likely to be introduced into or onto said article, and of which the other face of the substrate is an outer face, possibly convex, intended to be arranged towards a heat source. Advantageously, the electric cooking appliance (200) is chosen from the group consisting of electric crepe maker, electric raclette appliance, electric fondue appliance, electric grill, electric griddle, electric cooker, bread machine, electric pressure cooking appliance, waffle makers, rice cookers and jam makers.The electrical cooking appliance (200) comprises a coated cooking element (1) according to the invention and a heating source (210) configured to heat said coated cooking element (1). According to one embodiment, the household item according to the invention is a small heating household appliance. It may be an iron and the coated heating element is the soleplate of the iron or a hair care item and the coated heating element is one of the heating plates of said item. EXAMPLES The aims, aspects and advantages of the present invention will be better understood from the description given below of a particular embodiment of the invention presented as a non-limiting example. Of course, the invention is in no way limited to the embodiment described and illustrated which has been given only as an example.Modifications remain possible, in particular from the point of view of the constitution of the various elements or by substitution of technical equivalents, without departing from the scope of protection of the invention.1) Examples of embodiment:Materials:- PESo resin PolyEtherSulfone (PES) powder resin, micronized grade from SUMITOMO, polymer powder with a d50 between 11 and 15 µm.- Solvents:o propionamide- Reinforcing fillers:o Alumina,o Silicon Carbideo Pyrogenic silica,o Colloidal silicao Colloidal alumina. o Mica- Thickener:o 50% acrylic polymer solution in watero hydrogenated castor oil- Silicone resins:o Methyl-phenyl silicone resin, in flakeso Methyl silicone resin, in flakes- Solvent Alcoholo di propylene glycol butyl ether (DPNB),o MPG propylene glycol- Surfactant:o Fatty alcohol polyglycol ether- Anti-foaming agento Mineral oil- Pigments:o Mica or flakeso Carbon black:- Silicone oil:o A: non-reactiveo B: reactive- Other additives:o buffering agento anionic ester in ethanol / water, wetting agent,o aqueous dispersion of polydimethylsiloxane gum, surface tension agentExamples of the production of a cookware item according to the invention:On a flat aluminum disc (30 cm in diameter), previously degreased and sandblasted to obtain a roughness of 4 to 7 µm (Ra), is deposited by screen printing a continuous layer 3 chosen from the base layer compositions (3a1 and 3a2) as described above dessous :Layers 3a: Layer 3a1: Material Nature % wet % in cooked film Solvent DEMINERALIZED WATER 29.57 0.00 Solvent PROPIONAMIDE 22.18 0.00 Polymer PES 18.48 59.19 thermoplastic Wetting agent Fatty alcohol polyglycol ether 0.52 0.07 Acrylic thickener Acrylic polymer solution (50% in 5.48 1.95 water) Buffering agent Amino alcohol 1.05 0.00 Pigment Carbon black 4.13 4.14 Antifoam Mineral oil 1.24 0.20 Reinforcing filler Colloidal silica 4.13 4.01 Reinforcing filler Colloidal alumina 9.50 18.41 Reinforcing filler Silicon carbide 3.72 12.03100.00 100Layer 3a2: Material Nature % wet % in cooked film Silicone resin Methyl or methyl-phenyl silicone resin 18.75 45.07Solvent Alcohol Glycol ether 18.75 0.00Thickener Hydrogenated castor oil 0.62 1.45Reinforcing filler Mica 1.87 4.79Reinforcing filler Pyrogenic silica 1.25 3.20Pigment Carbon black 3.75 2.97Reinforcing filler Alumina 1.87 4.79Wetting agent Fatty alcohol polyglycol ether 1.19 0.12Solvent DEMINERALIZED WATER 14.56 0.00Solvent PROPIONAMIDE 10.92 0.00Polymer PES 10.92 27.66thermoplasticAcrylic thickener 50% acrylic polymer solution in 0.73 0.21water Buffering agent Amino alcohol 0.11 0.00Stretching agent Anionic ester in ethanol / water 1.25 1.12Solvent Alcohol Propylene glycol 5.94 0.00Reinforcing filler Colloidal alumina 3.75 5.74Reinforcing filler Colloidal silica 3.75 2.88100.00 100The thickness of this base layer 3a of the example is between 5 µm and 15 µm.The substrate, on which is applied the continuous base layer 3a as described above, is coated with a multi-layer non-stick coating consisting of an intermediate layer 3b (5-15µm) which is dried at 80°C and a top layer 3c (5-15µm). The whole being finally heated to 300°C for about 10 min, i.e. the process comprises only one baking step,after the deposition of the different layers. Layers 3b: The compositions of the intermediate layers 3b deposited by screen printing are as described below (layer 3b1 and layer 3b2). Layer 3b1: Material Nature %% in cooked wet film Solvent DEMINERALIZED WATER 33.63 0.00 Solvent PROPIONAMIDE 25.22 0.00 Polymer PES 21.02 79.52 thermoplastic Wetting agent Fatty alcohol polyglycol ether 0.59 0.09 Acrylic thickener 50% acrylic polymer solution in 6.23 2.62 water Buffering agent Amino alcohol 1.19 0.00 Pigment Carbon black 4.70 5.57 Antifoam Mineral oil 1.41 0.27 Reinforcing filler Colloidal silica 4.14 4.75 Reinforcing filler Mica 1.40 5.35 Glitter pigment 0.48 1.83100.00 100 Layer 3b2: Material Nature %% in cooked wet film Silicone resin Methyl or methyl-phenyl silicone resin 21.62 51.39 Solvent Alcohol Glycol ether 21.62 0.00 Thickener Hydrogenated castor oil 0.72 1.66 Reinforcing filler Mica 1.08 2.73 Reinforcing filler Pyrogenic silica 1.44 3.65Pigment Carbon black 4.32 3.39Wetting agent Fatty alcohol polyglycol ether 1.08 0.11Solvent DEMINERALIZED WATER 11.19 0.00Solvent PROPIONAMIDE 8.40 0.00PolymerPES 8.40 21.02thermoplastic Acrylic thickener 50% acrylic polymer solution in, 0,56 0,16 Water Buffering Agent Amino alcohol 0.09 0.00 Spreading Agent Anionic Ester in Ethanol / Water 1.44 1.28 Tensioning Agent Aqueous Dispersion of Gum 0,72 0,97polydimethylsiloxane surface Solvent Alcohol Propylene glycol 6.49 0.00 Reinforcing filler Colloidal alumina 7.21 10.92 Reinforcing filler Colloidal silica 3.60 2.73100.00 100 The compositions of the 3c top coats deposited by screen printing are as described below (coats 3c1 to 3c4):Top coat (3c)Coat 3c1:Material Nature %wet % in filmcooked Solvent DEMINERALIZED WATER 39.4 0.00Solvent PROPIONAMIDE 29.55 0.00Polymer PES 24.62 91.15thermoplastic Wetting agent Fatty alcohol polyglycol ether 0.69 0.10Acrylic thickener 50% acrylic polymer solution 3.44 1.42 in water Buffering agent Amino alcohol 0.3 0.00 Silicone oil A 2.00 7.33 100 100Layer 3c2: Material Nature %% in cooked wet film Silicone resin Methyl or methyl-phenyl silicone resin 30.00 70.62Solvent Alcohol Glycol ether 39.60 0.00Reinforcing filler Pyrogenic silica 1.00 2.50Thickener Hydrogenated castor oil 1.70 3.87Wetting agent Fatty alcohol polyglycol ether 1.65 0.17Solvent DEMINERALIZED WATER 8.54 0.00Solvent PROPIONAMIDE 6.41 0.00PolymerPES 6.41 15.89thermoplastic Acrylic thickener 50% acrylic polymer solution in 0,43 0,12 Water Buffering Agent Amino alcohol 0.06 0.00 Spreading Agent Anionic Ester in Ethanol / Water 1.50 1.31 Tensioning Agent Aqueous Dispersion of Gum 1,00 1,33polydimethylsiloxane surface Silicone oil B 1.00 2.45Silicone oil A 0.50 1.23Pigment Glitter 0.20 0.50100.00 100Layer 3c3:Material Nature %% in cooked wet film Silicone resin Methyl or methyl-phenyl silicone resin 7.1 23.44Solvent Alcohol Glycol ether 7.1 0.00Thickener Hydrogenated castor oil 0.1 0.32Reinforcing filler Pyrogenic silica 0.2 0.70Wetting agent Fatty alcohol polyglycol ether 0.4 0.06Solvent Alcohol Propylene glycol 12.82 0.00Spreading agent Anionic ester in ethanol / water 0.35 0.43Antifoam Mineral oil 0.7 0.12Solvent DEMINERALIZED WATER 27.3 0.00Solvent PROPIONAMIDE 20.48 0.00Polymer PES 20.48 71.21thermoplastic Wetting agent Fatty alcohol polyglycol ether 0.48 0.07Acrylic thickener 50% acrylic polymer solution in 1.39 0.54water Buffering agent Amino alcohol 0.2 0.00Silicone oil A 0.7 2.41Pigment Glitter 0.2 0.70 100 100Layer 3c4: Material Nature %% in cooked wet film Silicone resin Methyl or methyl-phenyl silicone resin 30.00 84.33 Solvent Alcohol Glycol ether 41.70 0.00 Thickener Hydrogenated castor oil 1.60 4.35 Reinforcing filler Pyrogenic silica 1.00 2.99 Wetting agent Fatty alcohol polyglycol ether 1.50 0.18 Solvent Alcohol Propylene glycol 20.00 0.00 Spreading agent Anionic ester in ethanol / water 1.50 1.57 Tensioning agent Aqueous dispersion of gum 1,00 1,58 polydimethylsiloxane surface Silicone oil B 1.00 2.93Silicone oil A 0.50 1.47Pigment Glitter 0.20 0.60100.00 100Examples of construction / architecture of heating elements according to the invention: 1 2 3 Base layer a1 a2 a1Layer b1 b2 b1 intermediate Top coat c1 c2 c3

Claims

CLAIMS 1 . Elément de chauffe revêtu (1) pour article ménager, comportant un substrat métallique (2) revêtu sur au moins une face (2a) par un revêtement (3) dépourvu de résine fluorocarbon and comprising at least the following layers and in this order from substrat métallique (2) : (3a) une couche de primaire constituée de polyéthersulfone (PES) ou d’un mélange de polyéthersulfone (PES) et d’une ou plusieurs résines silicones, et éventuellement : - d’une ou plusieurs charge(s) et / ou - d’un ou plusieurs additif(s), et / ou - d’un ou plusieurs agent(s) colorant(s) (3b) one or more intermediate layer(s) consisting of polyethersulfone (PES) or a mixture of polyethersulfone (PES) and one or more silicone resins, and éventuellement : - d’une ou plusieurs charge(s), et / ou - d’un ou plusieurs additif(s), et / ou - d’un ou plusieurs agent(s) colorant(s) (3c) topcoat consisting of polyethersulfone (PES), or consisting of a mixture of polyéthersulfone (PES) et d’une ou plusieurs résines silicones, ou constituée d’une ou plusieurs résines silicone, et éventuellement : - d’une ou plusieurs charge(s) et / ou - d’un ou plusieurs additif(s), et / ou - d’un ou plusieurs agent(s) colorant(s); it being understood that layer (3a), layer (3c) and at least one of layers (3b) are different. 2 . Elément de chauffe revêtu (1) selon la revendication 1, caractérisé en ce que layer (3a), layer (3c) and all layers (3b), when there are several, are all different. 3 . Elément de chauffe revêtu (1) selon la revendication 1 ou 2, caractérisé en ce that the PES content in the primer layer (3a) is lower than the PES content in the layer(s) (3b). 4 . Elément de chauffe revêtu (1) selon la revendication 3, caractérisé en ce quethe PES content increases from the primer layer (3a) to the top coat (3c).

5. Elément de chauffe revêtu (1) selon l’une quelconque des revendications précédentes, caractérisé en ce que la teneur en PES de la couche de primaire (3a) représente de 50 % à moins de 75 % en poids de la couche de primaire (3a).

6. Elément de chauffe revêtu (1) selon l’une quelconque des revendications previous, characterized in that the PES content of the intermediate layer (3b) représente de 75 % à moins de 85 % en poids de la couche intermédiaire (3b).

7. Elément de chauffe revêtu (1) selon l’une quelconque des revendications previous, characterized in that the PES content of the finishing layer (3c) represents de 85 % à 98 % en poids de la couche de finition (3c).

8. Elément de chauffe revêtu (1) selon l’une quelconque des revendications preceding, characterized in that the thickness of each of the layers of the coating (3a), (3b) and (3c) is between 5 µm and 15 µm. 9 . Elément de chauffe revêtu (1) selon l’une quelconque des revendications previous, characterized in that it further comprises a layer (3d) which will be the last couche du revêtement (3), lorsqu’elle est présente, constituée : - d’un silicone élastomère obtenu à partir d’au moins un organopolysiloxane porteur de reactive vinyl functions (-CH=CH2) and at least one other organopolysiloxane carrying fonctions réactives hydrure de silyle (Si-H) ou de fonctions réactives thiol (S-H); et possibly : - d’un ou plusieurs polymères thermoplastiques, et / ou - d’un ou plusieurs additif(s), et / ou - d’un ou plusieurs agent(s) colorant(s).

10. Procédé de fabrication d’un article ménager comprenant un élément de chauffe revêtu (1) d’un revêtement (3) selon l’une quelconque des revendications précédentes caractérisé par les étapes suivantes :a) a step of providing a metal substrate (2) in the form of a substantially flat metal substrate comprising two opposite faces or a support (2) of convex or hollow shape defining a concave inner face (21) and a convex outer face (22); b) where appropriate, when a metal substrate in the form of a substantially flat metal substrate is provided during step (a), a step of shaping said substrate to give it the shape of a support (2) of convex or hollow shape defining a concave inner face (21) and a convex outer face (22), said step (b) being carried out either before step (a), or before step (d) of producing the layers (3a), (3b) and (3c) of the coating (3), or after step (f) of baking and before the optional step (g) of producing the layer (3d) or after step (g); c) optionally, a step of treating at least one face (2a) of the metal substrate (2), to obtain a treated face (2a) promoting the adhesion of a layer of primaire (3a) sur le support (2) ;d) a step of applying the layers (3a), (3b) and (3c) of the coating (3); e) optionally a drying step between 50°C and 150°C after application of each of the layers (3a) (3b) and (3c); f) optionally a step of baking the element obtained in step d) or e) at a temperature between 250°C and 420°C g) optionally, a step of applying the layer (3d) to the element obtained in l'étape d), e) ou f) h) optionally a step of cooking the element obtained in step g) at a temperature comprise entre 250°C et 420°C.

11. Article ménager comprenant un élément de chauffe revêtu (1) selon l’une any of claims 1 to 9 or obtainable according to claim 10. 1 2. Article ménager selon la revendication 11 caractérisé en ce qu’il s’agit d’un kitchen article or an electrical cooking appliance and in that the layer (3c) or the layer (3d), when present, forms a cooking face.

3. Article ménager selon la revendication 12, caractérisé en ce que l’agent colorant of layer (3c) or layer (3d), when present, is glitter. 1 4. Article ménager selon la revendication 11, caractérisé en ce qu’il s’agit d’unculinary article or electrical cooking appliance and in that the layer (3c) or the layer (3d), when present, is intended to be placed in contact with a heating source.

5. Article culinaire (100) selon l’une quelconque des revendications 12 à 14, chosen from the group consisting of saucepan, frying pan, skillets or pots for fondue or raclette, stewpot, wok, sauté pan, crepe pan, grill, griddle, pot, casserole dish, bowl of cuiseur ou de machine à pain, moule culinaire, moules et plaques pour la pâtisserie, les barbecue plates and grills, preparation bowls. 1 6. Appareil électrique de cuisson (200) selon l’une quelconque des Claims 12 to 14, chosen from the group consisting of electric crepe maker, electric raclette machine, electric fondue machine, electric grill, electric griddle, electric cooker, bread machine, electric pressure cooking machine, waffle makers, rice cookers and jam makers. 1 7. Article ménager selon la revendication 11 caractérisé en ce qu’il s’agit d’un small household heating equipment. 1 8. Article ménager selon la revendication 17 caractérisé en ce qu’il s’agit d’un fer à repasser et que l’élément de chauffe revêtu (1) est la semelle du fer à repasser ou un hair care article and that the coated heating element is one of the heating plates of said article.

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