Method of manufacturing a coated cooking element with a hybrid surface

Abstract

The present invention relates to a method for manufacturing a coated cooking element, characterized in that it comprises the following steps and in this order: a) Providing a metal support (2) in the form of a substantially flat disc (20) having a face (2a) intended to be coated; b) Optionally pre-treating said face (2a) of said support; c) Applying at least one non-stick coating A (4; 8; 41, 42; 43, 44) and at least one coating B (3; 5; 51, 52; 53, 54; 57, 56, 55) to said optionally treated face (2a) of said support (2), B being different from A, neither A nor B comprising fluorocarbon resin, A covering only a central part of the support (2) in the form of a disc (4; 8) and B covering at least the peripheral part (3) of the disc (4) not covered by the coating A; and d) Possible deposit of at least one additional layer of coating, in particular decoration or finishing.The invention also relates to a culinary article or an electrical cooking appliance, comprising a coated cooking element obtained by said method. (Figure 5 to be attached).

Description

Title of the invention: Method for manufacturing a coated cooking element with a hybrid surface FIELD OF THE INVENTION

[0001] The invention relates to a method for manufacturing a coated cooking element with a hybrid surface. By "hybrid" is meant that said element comprises a support (or substrate) provided with at least two different coatings on the same face. According to the invention, neither of these two coatings of the cooking element comprises fluorocarbon resin. The invention relates in particular to a method comprising a shaping step carried out after the application of the coatings to the support.

[0002] The field targeted is primarily that of kitchenware and electrical cooking appliances. STATE OF THE ART

[0003] For several years, sol-gel coatings have been used to produce non-stick coatings for cookware. These coatings are called "sol-gel" because they are based on sol-gel chemistry. They are also called "ceramic". This makes it possible to gradually replace coatings based on fluorocarbon resins such as polytetrafluoroethylene (PTFE). However, on an industrial level, sol-gel coatings are always applied to previously shaped items. Indeed, the inorganic network that constitutes the sol-gel coating cannot deform without cracking. Such deformation results in a significant reduction in adhesion to the support, as well as less resistance to grease penetration in the case of a cookware in use. Sol-gel coatings cannot therefore be applied using the many flat coating techniques (screen printing, roller, inkjet, curtain, etc.).) and are generally spray-coated with a pneumatic gun. This results in a significant loss of product during spraying (depending on the shape of the part, the loss can represent between 30 and 70% of the applied sol-gel composition), and a problem of "overspray" (i.e. unavoidable but unwanted spraying outside the article), generally on the face opposite the coated face.

[0004] This is not the case for fluorocarbon coatings which have a capacity for deformation, in particular stretchability, and which can be deformed and shaped, and therefore be applied to flat supports by flat coating processes, before being heat treated and then shaped.

[0005] To overcome these drawbacks, patent application WO 2015 / 092332 describes a method in which the shaping of an article is carried out by a step of shaping shape of a metal part previously coated on at least one of its faces with a sol-gel coating, thanks to a suitable pre-condensation treatment of the sol-gel layer preceding shaping.

[0006] However, this solution is complicated to implement and expensive.

[0007] There therefore remains a need to remedy these drawbacks, in order to be able to shape a metal part previously coated on at least one of its faces with at least one sol-gel coating, without a significant reduction in adhesion to the support of the sol-gel coating, and having good resistance to the penetration of grease in the case of a culinary article in use. Statement of the invention

[0008] More particularly, the present invention proposes to produce a coated cooking element free of fluorocarbon resin, without complicating its manufacturing process, while retaining its essential qualities, namely good resistance, good durability and good cleanability. Summary of the invention

[0009] The subject of the invention is a method for manufacturing a coated cooking element (10, 10'), characterized in that it comprises the following steps and in this order: a. Provision of a metal support (2) in the form of a substantially flat disc (20) having a face (2a) intended to be coated; b. Possible prior treatment of said face (2a) of said support; c. Application of at least one non-stick coating A (4; 8; 41, 42; 43, 44) and at least one coating B (3; 5; 51, 52; 53, 54; 57, 56, 55) on said optionally treated face (2a) of said support (2), B being different from A, neither A nor B comprising fluorocarbon resin, A covering only a central part of the support (2) in the form of a disc (4; 8) and B covering at least the peripheral part (3) of the disc (4) not covered by the coating A; and d. Possible deposit of at least one additional layer of coating, in particular decoration or finishing.

[0010] The invention also relates to a culinary article comprising a coated cooking element obtained by the method of the invention.

[0011] The invention also relates to an electrical cooking appliance comprising a coated cooking element obtained by the method of the invention. DEFINITIONS

[0012] For the purposes of the present invention, the term "cooking element" means an element capable of being heated, and is capable of transmitting (or conducting) heat to an object in contact with said element. The heat (or heat energy) is provided either by its own heating system, either by an external heating system or by contact with a previously heated element.

[0013] For the purposes of the present invention, the term “cooking article” means a kitchen article intended for cooking and capable of coming, at least partially, into contact with food. To do this, it is intended to receive heat treatment.

[0014] The expression "object intended to receive heat treatment" is understood to mean, within the meaning of the present invention, an object which will be heated by an external heating system such as a frying pan, a saucepan, a sauté pan, a casserole dish, a wok, a barbecue grill or griddle, a crepe maker, a stew pot, a pot, a waffle iron, a grill, a baking pan or griddle, a bread machine bowl, a cooker bowl, a preparation bowl, or a frying pan or caquelon for fondue or raclette, and which is capable of transmitting the heat energy provided by this external heating system to a material or food in contact with said object.

[0015] The expression "electric cooking appliance" is understood to mean, 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, an electric griddle, an electric cooker, a bread machine, or an electric pressure cooking appliance.

[0016] For the purposes of the present invention, the term "coating" means a continuous layer, i.e. a single whole forming a total flat area covering the desired surface. Such a coating may be single-layer or comprise at least two layers.

[0017] For the purposes of the present invention, the term “sol-gel coating” means a coating synthesized by sol-gel method from a solution based on precursors in the liquid phase, which transforms into a solid by a series of chemical reactions (in particular hydrolysis and condensation) at low temperature. The coating thus obtained can be either organo-mineral or entirely mineral.

[0018] For the purposes of the present invention, the term "organo-mineral coating" means a coating whose network is essentially inorganic, but which comprises organic groups, in particular due to the precursors used for producing said coating and the baking temperature of the coating or due to the incorporation of organic fillers.

[0019] For the purposes of the present invention, the term "fully mineral coating" means a coating made of a completely inorganic material, free of any organic group. Such a coating can also be obtained by sol-gel method with a baking temperature of at least 400°C, or from precursors of the tetraethoxysilane (TEOS) type with a baking temperature which can be lower than 400°C.

[0020] For the purposes of the present invention, the term "base coat" (or "primer coat") means all coats excluding decoration and / or finishing: from the first coat applied directly to the support to the last coat applied before the first decoration coat or before the first finishing coat, when one of them is present.

[0021] For the purposes of the present invention, 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, of one or more colors. A decor is generally clearly visible to the user with the naked eye and at a conventional distance from which the article is used.

[0022] For the purposes of the present invention, the term "finish layer" or "finish" means a continuous and most often transparent surface layer. A finishing layer protects any underlying layer from mechanical attack and gives the coating its non-stick properties. A finishing layer is intended to be in contact with food in the case of food use.

[0023] For the purposes of the present invention, 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.

[0024] For the purposes of the present invention, 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. In general, the adjacent layers are in contact with each other over a delimitation zone, for example circular. As will be explained below, a slight overlap is possible in the delimitation zone.

[0025] By "wet layer", it is understood within the meaning of the present invention that the layer comprises all or part of its solvents.

[0026] For the purposes of the present invention, the term "alkyl" means a saturated, linear or branched monovalent hydrocarbon chain, generally comprising 1 to 10, preferably 1 to 6, carbon atoms. By way of example, mention may be made of methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl or pentyl groups.

[0027] For the purposes of the present invention, the term "alkoxy" means an alkyl group as defined above, linked to the rest of the molecule via an oxygen atom. By way of example, mention may be made of the methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, iso-butoxy, sec-butoxy, t-butoxy, or n-pentoxy groups.

[0028] For the purposes of the present invention, the term “aryl” means an aromatic hydrocarbon group, preferably comprising from 6 to 10 carbon atoms, and comprising one or more attached cycles, such as a phenyl or naphthyl group. Advantageously, it is phenyl.

[0029] For the purposes of the present invention, the term “alkenyl” means a hydrocarbon chain comprising at least one double unsaturation, terminal or in the chain, and preferably comprising from 6 to 10 carbon atoms, such as a vinyl or allyl group.

[0030] For the purposes of the present invention, the term “alkynyl” means a hydrocarbon chain comprising at least one triple unsaturation, terminal or in the chain, and preferably comprising from 6 to 10 carbon atoms.

[0031] By the term “D50” is meant, within the meaning of the present invention, the maximum dimension presented by 50% of the particles in number.

[0032] By the term “D90” is meant, within the meaning of the present invention, the maximum dimension presented by 90% of the particles in number.

[0033] By "X and / or Y" is meant according to the invention either X, or Y, or X and Y. DETAILED DESCRIPTION OF THE INVENTION Method

[0034] Step b) is optional, particularly if in step a) a metal support is provided which has been previously treated on its face intended to be coated.

[0035] In step b) of the method according to the invention, the face of the metal support on which the coatings will be applied can undergo a surface treatment making it possible to improve the adhesion of the coating(s) to said support. The support and the surface treatments are described in detail below.

[0036] Step c) is carried out after step a) or after steps a) and b). Step c) of applying coatings A and B is preferably carried out by contactless deposition such as spray or precision spray technologies, with pneumatic or digital control, for each of the two coatings A and B. The step of applying coating B can also be carried out by roller. The composition to be coated is generally in liquid or powder form.

[0037] The layers can be applied wet on wet or drying can be applied between each layer.

[0038] The coating formula to be coated is generally in aqueous form, the polymers of the continuous phase being generally in suspension form. Non-aqueous solvents may also be suitable.

[0039] The application of the coatings is carried out according to the invention by depositing the coatings A and B, or even according to step d) by depositing at least one additional layer, in particular decorative and / or finishing.

[0040] Generally speaking, as is known to those skilled in the art, it is preferable for any first layer applied directly to the support to be well adherent to said support and to provide all of its mechanical properties to the coating (hardness, scratch resistance). This first layer comprises only coatings A and / or B, in particular according to the two preferred embodiments described below.

[0041] The central part and the peripheral part of the support generally complement each other to correspond to the entire surface of the support. Thus, the support is coated with coating A, in the form of a disc, in its central part and with coating B in its peripheral part, most often in the form of a disc or ring, the two coatings being substantially complementary (a slight overlap being possible in the delimitation zone) and being able to be covered with one or more other layers, in particular finishing layers.

[0042] The coating A is not present in the peripheral part (3; 5) of the support.

[0043] Coating B may be present in the central part (8) of the support. In this case, it is covered by coating A.

[0044] According to one embodiment, coating B covers the entire support below coating A or coating B covers the peripheral part of the support not covered by coating A. The term “covers the peripheral part of the support not covered by coating A” means that coating B strictly covers the peripheral part of the support not covered by coating A or that coating B covers the peripheral part of the support not covered by coating A with a slight overlap of coating A on coating B or of coating B on coating A. The term “slight overlap” means an overlap between 0 mm and 10 mm.

[0045] Coatings A and B, as well as their architecture, are described in detail below.

[0046] The optional step d) of applying at least one layer, in particular decorative and / or finishing, is well known to those skilled in the art.

[0047] Any coating or decorative layer is generally applied in wet form. Indeed, the composition of the layer may further comprise at least one solvent, typically polar protic or aprotic such as esters or amides. This solvent may be non-toxic. The solvent may advantageously comprise at least one alcohol, and may preferably be chosen from isopropanol, methanol, ethanol and mixtures thereof.

[0048] Preferably, all or part of the solvents in the wet layer are removed at the end of the process, either naturally or by physical treatment, for example by thermal drying, by air flow drying or by vacuum treatment.

[0049] Thus, any step of applying coating or decoration or finishing can be advantageously followed by a drying step, as is well known in the art. skilled person. Advantageously, the manufacturing method according to the invention comprises a drying step between 80 and 150°C after application of each of the layers. Drying can be carried out by convection or infrared (IR).

[0050] Preferably, a drying step is carried out after the application of each layer, then the possible baking of the coated support is carried out after application of the last coating layer.

[0051] According to a preferred embodiment, the method of the invention further comprises the following step:

[0052] e) Heat treatment of the coated support after step c) or d) leading to obtaining the coated cooking element.

[0053] The optional step e) of heat treatment of the coated support makes it possible to densify the coating layers applied to the support. This step is also known as the baking step or even the sintering step in certain cases. When it is carried out, it is carried out after step c) or even after steps c) and d). It is generally carried out simultaneously for all of the applied layers. This embodiment makes it possible to filmify, fuse and crosslink all of the layers together so that they form only one. The coatings of the support thus form a single layer, even if this single layer is not homogeneous, that is to say it has heterogeneity of composition and / or architecture.

[0054] Generally the curing temperature of step e) is from 230°C to 430°C. The advantageous curing temperature of step e) is from 230 to 300°C in the presence of organopolysiloxane polymers in the continuous phase, preferably from 230 to 280°C, even more preferably from 230 to 250°C. The advantageous curing temperature of step e) is from 230 to 430°C in the presence of thermoplastic polymers in the continuous phase, preferably from 250 to 400°C, even more preferably from 280 to 380°C.

[0055] According to a preferred embodiment, the method of the invention further comprises the following step:

[0056] f) Shaping the coated cooking element resulting from step c), d) or e) to obtain a coated cooking element in a concave shape on said face, defining a bottom and a lateral edge extending from the bottom, the change in curvature between the bottom and the lateral edge being located in a part of the peripheral part of the support coated with coating B.

[0057] Advantageously, this step of shaping the coated support makes it possible to preserve the properties, in particular the mechanical properties, of coating A for the base, while allowing shaping after the deposition of coatings A and B, because coating B is chosen so as to be more capable of deforming than coating A and therefore to undergo shaping without cracking.

[0058] Preferably, the change in curvature generated by the shaping is carried out at the delimitation zone between the coating A and the coating B. In other words, the central part constitutes the bottom and the peripheral part constitutes the lateral edge (or skirt) of the hollow coated cooking element. By "hollow", according to the invention, is meant a concave shape on the coated face or to be coated.

[0059] The change in curvature is also carried out in a portion of the coated cooking element comprising only coating B, not coating A. In this case, preferably, the central portion and a portion of the peripheral portion constitute the bottom and the other portion of the peripheral portion constitutes the side edge (or skirt) of the hollow coated cooking element.

[0060] Shaping is also called stamping. It makes it possible to obtain a final shape of hollow coated cooking element, generally with an inner face capable of receiving food and an outer face intended to be arranged on the side of a heat source, the inner face being the face provided with coatings A and B, and the shaping being carried out by deformation of a part of the cooking element which includes coating B and which most often does not include coating A.

[0061] The possibility of being able to shape a cooking article coated with a coating A and a coating B, thanks to the method according to the invention, brings numerous advantages both on an industrial level and in terms of the aesthetic possibilities conferred on the hollow cooking elements and therefore on the articles containing them.

[0062] Thus, thanks to the method according to the invention, it is possible to use, for carrying out step c) of applying coatings A and B, flat coating techniques, which allow on the one hand a significant saving in coating consumption from an industrial point of view, and on the other hand the elimination of the problem of spraying outside the article (or "overspray").

[0063] In addition, working on flat metal before applying the coatings simplifies the possible step b) of surface preparation (sandblasting, degreasing, chemical stripping, etc.). From an aesthetic point of view, it is also very advantageous to apply coatings A and B using flat techniques, because these techniques give access to greater decoration possibilities. Indeed, it is much easier to create decoration on flat discs (by flexography, roller, inkjet, or using several layers of screen printing, etc.), than with the spraying technique (which requires the use of covers), or the technique of inserting decoration by pad printing on the bottom of the article, etc.).

[0064] Finally, the process makes it possible to obtain a coated cooking element with good non-stick performance, even without the presence of fluorocarbon resin. Architecture

[0065] According to one embodiment, each of the coatings A and B according to the invention comprises one or more layers applied to the support.

[0066] Thus, the coating A is single-layer (i.e. formed of a single layer) or multi-layer (i.e. formed of at least two layers). According to a preferred embodiment, the coating A is two-layer, i.e. formed of two layers, for example a base layer and a decorative or finishing layer, or three-layer, i.e. formed of three layers. All the layers may have an identical composition. All the layers may also have a different composition from one another.

[0067] Similarly, coating B is single-layer (i.e. formed of a single layer) or multi-layer (i.e. formed of at least two layers). According to a preferred embodiment, coating B is two-layer or three-layer. The first layer is generally a base layer. The last layer (2nd if two-layer, 3rd if three-layer) may be a decorative or finishing layer. All the layers may have an identical composition. All the layers may also have a different composition from one another.

[0068] When the coating A or B is multi-layer, the different layers have been applied successively. Advantageously, the coating A or B comprises one to three layers, preferably two, applied to the support.

[0069] It is possible for the coating A or B to comprise at least one intermediate layer, preferably two intermediate layers which may be decorative layers.

[0070] According to one embodiment, the decorative layer is continuous and covers the entire surface of the support, regardless of the layer on which it is deposited. According to another embodiment, the decorative layer does not cover this entire surface and forms at least one decoration.

[0071] The finishing layer may cover the entire surface of the support, regardless of the layer on which it is deposited. Preferably, each of the coatings A and B comprises a finishing layer, these two finishing layers being different from each other.

[0072] According to a first preferred embodiment of the invention, coatings A and B are deposited in step c) in adjacent layers, coating A being deposited in the center of the support in the form of a disc, preferably according to a given radius, and coating B being deposited on the part of the support not covered by coating A. The coating order (A then B or B then A) is generally not important.

[0073] According to a second preferred embodiment of the invention, distinct from the first preferred embodiment of the invention, the coatings A and B are deposited in step c) in overlapping layers, the coating B being deposited over the entire support, then coating A being deposited in the center of the support in the form of a disc, preferably according to a given radius, above coating B. Metal support

[0074] The metal support provided for step a) according to the invention is generally a support made of aluminum, stainless steel, cast iron or aluminum, iron, titanium, copper, or mixtures thereof.

[0075] For the purposes of the present invention, the term “aluminum” means a metal consisting of 100% aluminum or an aluminum alloy.

[0076] Advantageously, the metal support is an aluminum support, a stainless steel support or a multi-layer metal support, the face on which the coatings will be applied is made of aluminum alloy or stainless steel. Preferably, the metal support comprises alternating layers of metal and / or metal alloy. More preferably, the metal support is an aluminum support.

[0077] The metal support may be a two-layer or three-layer support, 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.

[0078] Advantageously, the thickness of the metal support is between 0.5 mm and 10 mm.

[0079] According to one embodiment, the surface of the face of the metal support on which the coatings will be applied 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.

[0080] Advantageously, the face of the support on which the coatings will be applied can be treated so as to increase its specific surface area; for an aluminum support, 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 projection (flame, plasma or arc spray). Other metal supports can also be polished, sandblasted, brushed, micro-blasted or receive an addition of material by means of a technology such as thermal projection (flame, plasma or arc spray).

[0081] As metal supports whose surface has been treated and which can be used in the present invention, mention may advantageously be made of supports made of anodized or non-anodized aluminum, optionally polished, brushed, sandblasted, shot-blasted or micro-blasted, supports made of anodized or non-anodized aluminum alloy, optionally polished, brushed, sandblasted or micro-blasted, supports made of steel, optionally polished, brushed, sandblasted, shot-blasted or micro-blasted, stainless steel supports, possibly polished, brushed, sandblasted or micro-blasted, cast steel, aluminum or iron supports, and copper supports, possibly hammered or polished.

[0082] According to one embodiment, the surface of the face to be coated with the metal substrate 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.

[0083] Advantageously, the support may be chosen from supports comprising ferritic stainless steel / aluminum / austenitic stainless steel layers, supports comprising stainless steel / aluminum / copper / aluminum / austenitic stainless steel layers, supports made of cast aluminum, aluminum or aluminum alloys lined with an outer base of stainless steel, metallic co-laminated supports, for example two-layer co-laminated supports 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).

[0084] Advantageously, the average arithmetic roughness Ra of the surface of the face of the metal support on which the coatings will be applied is greater than or equal to 1 μm.

[0085] The arithmetic mean 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 fitted 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 arithmetic mean roughness Ra. Coatings

[0086] The coatings according to the invention do not comprise fluorocarbon resin.

[0087] Advantageously, the coating A obtained according to the invention is a non-stick coating, that is to say that the food does not adhere substantially to said coating.

[0088] The coating A or B obtained according to the invention is advantageously solid after drying. According to the invention, the term "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.

[0089] According to a preferred embodiment, the coating A comprises at least one material chosen from the following materials, alone or as a mixture: the compositions sol-gels, polyarylether ketones (PAEK), aromatic thermoplastic polymers other than PAEK, heterocyclic thermoplastic polymers, and organopolysiloxane polymers; preferably coating A comprises a sol-gel composition.

[0090] Such a material constitutes the continuous phase of coating A.

[0091] Advantageously, the coating A consists of: - a material chosen from the following materials, alone or in a mixture: sol-gel compositions, polyarylether ketones (PAEK), aromatic thermoplastic polymers other than PAEK, heterocyclic thermoplastic polymers, and organopolysiloxane polymers, - fillers, - coloring agents, - additives.

[0092] According to a preferred embodiment, the coating B comprises at least one material chosen from the following materials, alone or in a mixture: polyarylether ketones (PAEK), aromatic thermoplastic polymers other than PAEK, heterocyclic thermoplastic polymers, and organopolysiloxane polymers; preferably the coating B comprises a polyarylether ketone or an aromatic thermoplastic polymer other than PAEK, even more preferably the coating B is a polyether ether ketone PEEK and / or a polyether sulfone PES and / or an organopolysiloxane polymer. The coating B may comprise a sol-gel composition but only in a mixture with at least one other of the materials listed above, not alone.

[0093] Such a material constitutes the continuous phase of coating B.

[0094] Advantageously, the coating B consists of: - a material chosen from the following materials, alone or in a mixture: polyarylether ketones (PAEK), aromatic thermoplastic polymers other than PAEK, heterocyclic thermoplastic polymers, and organopolysiloxane polymers, - fillers, - coloring agents, - additives. Continuous phase

[0095] The continuous phase is an essential component of the coating. In general, the coating comprises at least 20% by weight of continuous phase in the wet state, relative to the total weight of the coating. As a corollary, this means that other components which do not materially affect the essential characteristics of the coating may be present (typically fillers and / or additives and / or agents colorants), generally these other components are present at no more than 50% by weight in the wet state, relative to the total weight of the coating. Sol-gels (SG)

[0096] The sol-gel composition is organo-mineral or entirely mineral. Coatings synthesized by sol-gel method from precursors of the metal polyalkoxylate type have a hybrid network, generally of silica with grafted alkyl groups. A sol-gel composition generally comprises at least one colloidal metal oxide and at least one precursor of the metal alkoxide type.

[0097] The metal oxide is preferably a colloidal metal oxide chosen from colloidal silica and / or colloidal alumina and / or colloidal zirconia or / or colloidal titanium.

[0098] Preferably, a metal alkoxide chosen from the group consisting of:

[0099] - precursors corresponding to the general formula Mi(0Ri)n,

[0100] - the precursors corresponding to the general formula M2(OR2)(ni)R2-, and

[0101] - the precursors corresponding to the general formula M3(OR3)(n 2)R32, with:

[0102] Ri, R2, R3 or R3' denoting an alkyl group,

[0103] R2' denoting an alkyl or aryl or alkenyl or alkynyl group such as a phenyl, vinyl or allyl,

[0104] n being an integer corresponding to the maximum valence of the metals Mb M2 or M3,

[0105] Mi M2 or M3 designating a metal chosen from Si, Zr, Ti, Sn, Al, Ce, V, Nb, Hf, Mg or Ln.

[0106] Advantageously, the metal alkoxide of the sol-gel solution is an alkoxysilane.

[0107] As alkoxysilanes which can be used in the sol-gel solution of the process of the invention, mention may in particular be made of methyltrimethoxysilane (MTMS), tetraethoxysilane (TEOS), methyltriethoxysilane (MTES), dimethyldimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, and mixtures thereof.

[0108] Preferably, the alkoxysilanes MTES and TEOS are used, because they have the advantage of not containing methoxy groups. Indeed, the hydrolysis of methoxy leads to the formation of methanol in the sol-gel formulation, which, given its toxic classification, requires additional precautions during application. Conversely, the hydrolysis of ethoxy groups only generates ethanol with a more favorable classification and therefore less restrictive usage requirements.

[0109] The formation of the sol-gel coating consists of mixing an aqueous composition X comprising the colloidal metal oxide and a solution Y comprising the alkoxide metallic. The mixture is advantageously carried out in a ratio of 40 to 75% by weight of the aqueous composition relative to the weight of the sol-gel composition (X + Y), so that the quantity of colloidal metal oxide represents 5 to 50% by weight of the sol-gel composition (X + Y) in the dry state.

[0110] The aqueous composition X may further comprise a solvent, in particular a solvent comprising at least one alcohol.

[0111] The aqueous composition X may further comprise at least one silicone oil.

[0112] The aqueous composition X may further comprise a pigment.

[0113] The aqueous composition X may further comprise a mineral filler.

[0114] The aqueous composition X may also comprise fumed silica, the function is the regulation of the viscosity of the sol-gel composition and / or the gloss of the dry coating.

[0115] Solution Y may further comprise an acid in Bronsted or Lewis terms. Advantageously, the metal alkoxide precursor of solution B is mixed with an organic, mineral Lewis acid which represents 0.01 to 10% by weight of the total weight of solution Y.

[0116] Particular examples of acids which can be used for mixing with the metal alkoxide precursor are acetic acid, citric acid, hydrochloric acid or formic acid.

[0117] Solution Y may further comprise a solvent, in particular a solvent comprising at least one alcohol.

[0118] Solution Y may further comprise at least one silicone oil.

[0119] Solution Y may further comprise metallic flakes.

[0120] According to an advantageous embodiment of the process of the invention, the solution Y may comprise a mixture of one of the alkoxysilanes as defined above and an aluminum alcoholate. PAEK

[0121] Polyarylether ketones (PAEK) are generally selected from the group consisting of: polyether ketones (PEK), polyether ether ketones (PEEK), polyether ketone ketones (PEKK), polyether ether ketone ketones (PEEKK) and polyether ketone ether ketone ketones (PEKEKK). PAEK most often comprises, preferably are, PEEK or PEKK. Even more preferably, PAEK are PEEK.

[0122] Aromatic thermoplastic polymers other than PAEK

[0123] Aromatic thermoplastic polymers other than PAEK are generally chosen from poly(phenylene oxide) (PPO), polyaryl ether sulfones (PAES), and in particular polyether sulfone (PES), polyphenylene ether sulfone (PPSU), polyphenylene sulfide (PPS), poly(arylene sulfide) (PAS), liquid crystal polymers and their mixtures.

[0124] The aromatic thermoplastic polymers other than PAEK preferably comprise PES or PPS. Even more preferably, the aromatic thermoplastic polymers other than PAEK are PES.

[0125] An amorphous, non-crystalline aromatic thermoplastic polymer, such as PPSU / PES (Polyethersulfone), makes it possible to improve the film formation of the coating because its glass transition temperature is much lower than the melting temperature of PAEK, which improves adhesion to the support. This also advantageously makes it possible to improve the ductility of the material and to promote its capacity to be stretched and stamped. Heterocyclic thermoplastic polymers

[0126] The heterocyclic thermoplastic polymers are generally chosen from polyether imide (PEI), polyimides (PI), polyamide imides (PAI) and polybenzymidazoles (PBI). Organopolysiloxane polymers

[0127] In 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.

[0128] This crosslinking can be done by thermal activation, or chemical activation using a catalyst, such as platinum.

[0129] 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.

[0130] Advantageously, these precursors are polymeric or oligomeric, either in the form of silicone oils of variable degree of branching, or in the form of resins. silicones of varying 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.

[0131] 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.

[0132] 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.

[0133] The silicone resin forms a network which can be made up of a combination of 4 simple organosiloxane units designated 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.

[0134] [Tables 1] Structure Degree of substitution by oxygen Symbol 1 M ? '"OSrO"" R 2 0 R Ô ï 3 T ô è 4 Q

[0135] The organopolysiloxane material or polymer is obtained by crosslinking from precursors which may be monomeric or polymeric, or intermediately which may 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.

[0136] The polymeric precursors are organopolysiloxanes. These macromolecules are formed from 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, it being possible for different natures of R to be present on the same macromolecule.

[0137] 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 lightly branched organopolysiloxanes are generally liquid, more or less viscous at room temperature, and are called silicone oils. Branched or highly branched (pre-crosslinked) organopolysiloxanes constitute a network at the scale 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.

[0138] 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.

[0139] 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.

[0140] All these 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 comprising 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.

[0141] 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.

[0142] 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 of 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.

[0143] Polymer precursors reacting by polyaddition may include, for example, polymethylhydrosiloxane, vinylmethylsiloxane, vinyl-terminated polydimethylsiloxane (PDMS), in particular linear, vinyl-terminated diphenylsiloxane-dimethylsiloxane copolymers, hydride-terminated polydimethylsiloxanes, hydride-terminated polyphenylmethylsiloxanes, cyclic vinylmethylsiloxane, vinyl-MQ resin, trimethylsilyl-terminated polymethylhydrosiloxane, trimethylsiloxane-terminated dimethylsiloxane copolymer, MQ resin hydride, and the like, as well as combinations thereof.

[0144] The polymeric precursors reacting by hydrolysis-polycondensation, whether they are 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 alkoxy-silanes and their oligomers, and all similar macromolecules and their mixtures.

[0145] 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.

[0146] Monomeric, oligomeric and / or polymeric precursors, in particular silicone resins, copolymerized or not with an organic polymer, play the role of polymeric binder in order to obtain the solid organopolysiloxane polymer combined with the thermoplastics of each layer.

[0147] Silicone oil type organopolysiloxane precursors can be considered as additives if they are added in small quantity (generally between 0.1 and 10% dry) in the whole formula of a layer, independently of the other components for the formation of the solid organopolysiloxane polymer.

[0148] Crosslinking may require a catalyst:

[0149] - In the case of crosslinking of 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 tin dibutyl laurate.

[0150] - In the case of the crosslinking of organopolysiloxanes by hydrosylilation, the addition 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.

[0151] A crosslinking agent, for example carrying Si-H bonds, may be present.

[0152] The advantage of using the above polymers of very high thermal stability, in particular PAEKs, for continuous use conditions at 260°C, is also to benefit from their very high mechanical properties (Young's modulus, tribology, low coefficient of friction, low surface energy, etc.) and their chemical resistance properties (in acidic and basic conditions, excellent resistance to many solvents), their biocompatibility, their biostability and their recyclability.

[0153] According to a preferred embodiment, the pairs of coatings A and B are chosen from the following pairs (coating A; coating B): (sol-gel coating; ethoxy functionalized polyester silicone resin and / or methoxy polyester silicone and / or methyl phenyl silicone and / or methyl silicone), (sol-gel coating; polyether ether ketone PEEK and / or polyether sulfone PES). Other possible coating component(s)

[0154] Each of the coatings A and B advantageously comprises at least one other optional component, typically chosen from fillers, additives, coloring agents and their mixtures.

[0155] According to another embodiment, the coating A or B comprises at least one layer comprising:

[0156] - a continuous phase;

[0157] - possibly one or more charge(s);

[0158] - possibly one or more additive(s);

[0159] - optionally one or more coloring agent(s).

[0160] According to another embodiment, the coating A or B comprises at least one layer consisting of:

[0161] - a continuous phase;

[0162] - possibly one or more charge(s);

[0163] - possibly one or more additive(s);

[0164] - optionally one or more coloring agent(s).

[0165] According to another embodiment, all the layers of coating A or B comprise:

[0166] - a continuous phase;

[0167] - possibly one or more charge(s);

[0168] - possibly one or more additive(s);

[0169] - optionally one or more coloring agent(s).

[0170] According to another embodiment, all the layers of coating A or B consist of:

[0171] - a continuous phase;

[0172] - possibly one or more charge(s);

[0173] - possibly one or more additive(s);

[0174] - optionally one or more coloring agent(s). Charges

[0175] The possible presence of at least one filler makes it possible to provide mechanical reinforcement and also, where appropriate, lubricating properties, hydrophobicity properties, while improving the mechanical resistance and thermal conductivity of the coating.

[0176] Fillers can help to add color to the coating.

[0177] Advantageously, if it is present, the charge is chosen from the group consisting of ceramic fillers (SiO2, etc.), mineral and / or metallic fillers (A12O3, TiO2, etc.) and / or hydrophobic silicas and / or diamond particles and their mixtures.

[0178] Preferably, the filler is 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.

[0179] Preferred fillers in combination with organopolysiloxanes are:

[0180] - reinforcing fillers: silica or carbonates with filler levels of minimum 10-15% by weight and up to 60% by weight, relative to the total weight of the coating,

[0181] - alumina, hydrated alumina, aluminum trihydroxide, silicon carbides (SiC),

[0182] - silica (precipitated or pyrogenic) with a D50 less than 0.1 pm and a surface BET specific greater than 30 m2 / g and preferably between 30 and 500 m2 / g,

[0183] - 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.

[0184] Advantageously, the average diameter D50 of the charges is between 0.1 and 50 pm, advantageously still between 5 and 15 pm.

[0185] Advantageously, the proportion of fillers in a layer is between 0.5 and 60%, preferably between 5 and 50%, by dry weight relative to the total weight of said layer after cooking. Additives

[0186] Advantageously, if present, the additive is chosen from the group consisting of anti-foaming agents, dispersing agents, wetting agents, thickening agents, pH adjusters and mixtures thereof.

[0187] Anti-foaming agents are generally chosen from the group consisting of mineral oils, diols, hydrocarbons, glycerides, oxirane (or ethylene oxide), emulsified fatty acids and their mixtures.

[0188] The surfactants are generally chosen from the group consisting of glycol ethers, ethoxylated alcohol excluding alkyl phenol ethoxylates (APE), gemini surfactants and mixtures thereof.

[0189] The dispersing agents are generally chosen from the group consisting of anionic dispersants such as fatty acid derivatives, and mixtures thereof.

[0190] The thickening agents are generally chosen from the group consisting of acrylic-based or polyurethane-based copolymers, cellulose and its derivatives, fumed silica, and mixtures thereof.

[0191] pH adjusters are generally chosen from the group consisting of Brônsted bases: ammonia, amines (triethylamine, triethanolamine, etc.), hydroxides (soda, potash, etc.), carbonates and their mixtures.

[0192] A preferred adhesion promoter in combination with the organopolysiloxanes is an organosilane or organopolysiloxane having three silicon-bonded hydrolyzable groups per molecule.

[0193] Advantageously, the proportion of additives in each coating layer A or B is less than 20% by weight relative to the total weight of said coating. Coloring agents

[0194] Advantageously, the coating may comprise at least one coloring agent.

[0195] Advantageously, the coloring agent(s) is / are chosen from the group consisting of thermochromic pigments, thermostable pigments, glitter and mixtures thereof. Thermochromic pigments

[0196] Preferably, the thermochromic pigment(s) is / are chosen from the group consisting of Bi2O3, Fe2O3, V2O5, WO3, CeO2, In2O3, Yi^CaojeTii^Vo.ieCW Agi, (Bii x Ax)(VryMy)O4with: - x is equal to 0 or x is between 0.001 and 0.999, - y is equal to 0 or y is between 0.001 and 0.999, - A and M are chosen 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.

[0197] Knowing that A and M are different from each other, when:

[0198] - A is an alkali metal, it can be chosen from Li, Na, K, Rb, Cs,

[0199] - M is an alkali metal, it can be chosen from Li, Na, K, Rb, Cs,

[0200] - A is an alkaline earth metal, it can be chosen from Be, Mg, Ca, Sr, Ba,

[0201] - M is an alkaline earth metal, it can be chosen from Be, Mg, Ca, Sr, Ba,

[0202] - 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,

[0203] - 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,

[0204] - A is a poor metal, it can be chosen from Al, Zn, Ga, In, Sn,

[0205] - M is a poor metal, it can be chosen from Al, Zn, Ga, In, Sn,

[0206] - A is a metalloid, it can be chosen from B, Si, Ge, Sb,

[0207] - M is a metalloid, it can be chosen from B, Si, Ge, Sb,

[0208] - A is a lanthanide, it can be chosen from La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu,

[0209] - M is a lanthanide, it can be chosen from La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu.

[0210] Preferably, A and M different from each other are B and / or Mg.

[0211] Preferably, the pigment (Bii.xAx)(Vi.yMy)04 has a monoclinic scheelite crystallographic form at room temperature.

[0212] Preferably, x and y are 0, i.e. the pigment (Bii_xAx)(Vi yMy)O4 is Bismuth Vanadate (BiVO4). Advantageously, a BiVO4 with a monoclinic scheelite crystallographic structure at room temperature is used.

[0213] Bismuth Vanadate is a yellow inorganic compound with the formula BiVO4, widely used for its color properties and its lack of toxicity. Registered in the Colour Index International database as QI Pigment Yellow 184, it is marketed by Heubach (Vanadur®), BASF (Sicopal®), FERRO (Lysopac) and Bruchsaler Farbenfabrik (Brufasol®). Thermostable pigments

[0214] Preferably, the thermostable pigment(s) is / are chosen from the group consisting of:

[0215] - Yellow titanium rutile pigment,

[0216] - Yellow pigment derived from bismuth, for example selected from vanadates of stabilized bismuth (Py i84)

[0217] - Red pigment, for example selected from perylene red (for example PR149, PR178 and PR224), iron oxide,

[0218] - Orange pigment of bismuth oxyhalides type (PO85),

[0219] - Bismuth vanadate orange pigment (PO86)

[0220] - Zinc tin titanium orange pigment (PO82)

[0221] - Cerium sulfide orange pigment (PO75; PO78)

[0222] - Orange-yellow pigment of the antimony titanium chrome rutile type (PBr24)

[0223] - Orange-yellow pigment of tin and zinc rutile type (Py2i6)

[0224] - Niobium tin zinc sulfide orange-yellow pigment (Py227)

[0225] - Orange-yellow pigment of double oxides of tin and niobium

[0226] - Co3(PO4)2

[0227] - LiCoPO4

[0228] - CoA12O4

[0229] - Cr2O3

[0230] - TiO2

[0231] - Black pigment PBk28 (Copper chromite black spinel)

[0232] - and their mixtures. Sequins

[0233] 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 that can be used in the context of the present invention can be treated to give a particular color effect.

[0234] 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 sequins

[0235] Advantageously, the glitter(s) is / are hologram glitter, that is to say a mixture of magnetizable particles and non-magnetizable particles.

[0236] The magnetizable particles may advantageously be particles comprising at least one ferromagnetic metal. These magnetizable particles may 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 steps of implementing the coating, or else 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.

[0237] According to one embodiment, a portion of said magnetizable particles is oriented so as to form a three-dimensional decoration.

[0238] 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.

[0239] 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.

[0240] Advantageously, the magnetizable particles have a dimension D50 less than or equal to 23 pm.

[0241] Advantageously, the non-magnetizable particles have a dimension D90 of between 20% and 250% of the dimension D90 of the magnetizable particles.

[0242] Advantageously, the magnetizable particles and / or the non-magnetizable particles are colored on the surface.

[0243] Advantageously, the non-magnetizable particles consist of mica, aluminum, or mica coated with titanium dioxide.

[0244] Advantageously, the magnetizable particles consist of iron, iron oxide, iron-coated aluminum, or iron-coated mica, the iron being in ferritic form. Article

[0245] The invention relates to a culinary article comprising a coated cooking element obtained by the method according to the invention.

[0246] Such a culinary article is capable of receiving food on the coated face of said coated cooking element.

[0247] Advantageously, the culinary article is chosen from the group consisting of saucepans, frying pans, skillets or fondue or raclette pots, stewpots, woks, sauté pans, crepe makers, grills, barbecue plates and grills, pots, casseroles, cooker bowls, bread machine bowls, waffle irons, barbecue plates and grills, baking molds and plates, and preparation bowls, preferably from the group consisting of saucepans, frying pans, skillets or fondue or raclette pots, stewpots, woks, sauté pans, pots, casseroles, cooker bowls, bread machine bowls, baking molds and plates, and preparation bowls.

[0248] The invention also relates to an electrical cooking appliance comprising a coated cooking element obtained by the method according to the invention.

[0249] Such an electrical cooking appliance is capable of receiving food on the coated face of said coated cooking element, said appliance comprising a heating source configured to heat said coated cooking element.

[0250] Advantageously, the electric cooking appliance is chosen from the group consisting of electric crepe makers, electric raclette appliances, electric fondue appliances, electric grills, electric griddles, electric cookers, bread makers, and electric pressure cooking appliances, preferably from the group consisting of electric raclette appliances, electric fondue appliances, electric cookers, bread makers, and electric pressure cooking appliances. DESCRIPTION OF FIGURES

[0251] Other advantages and particularities of the present invention will result from the description which follows, given by way of non-limiting example and made with reference to the examples and the corresponding appended figures.

[0252] [Fig. 1] schematically represents a method for obtaining a cooking element (10) comprising monolayer coatings A (4) and B (3) in adjacent layers.

[0253] [Fig.2] schematically represents the hollow cooking element (1) obtained by the method of [Fig.l].

[0254] [Fig.3] schematically represents a method for obtaining a cooking element (10') comprising single-layer coatings A (8) and B (5) in overlapping layers.

[0255] [Fig.4] schematically represents the hollow cooking element (1') obtained by the method of [Fig.3].

[0256] [Fig.5] schematically represents a hollow cooking element (100) obtained by a production process similar to that of [Fig.l], with the sole difference that the coatings A and B in adjacent layers are each bilayer (41, 42; 51, 52).

[0257] [Fig.6] schematically represents a hollow cooking element (100') obtained by a process close to the process of [Fig.3], with the only difference that the coatings A and B in overlapping layers are both two-layer (43, 44; 53, 54).

[0258] [Fig.7] schematically represents a hollow cooking element (100”) close to the element (100') obtained in [Fig.6], with the difference that the angle due to the shaping, between the bottom and the lateral edge, is higher, and that the coating B is three-layer (55, 56, 57).

[0259] Identical elements shown in Figures 1 to 7 are identified by identical reference numerals.

[0260] [Fig.l] schematically represents the manufacture of a coated cooking element (10) according to the invention according to a first architecture (adjacent layers). A metal support (20) in the form of a flat disc is provided (step a)), which has a face (2a) intended to be coated. The surface of the face (2a) has undergone or is undergoing a possible surface treatment (step b)) (not shown). A coating A is applied in a central layer (4) then a coating B is applied in a peripheral layer (3) (step c)). A heat treatment step is carried out (step e)). A substantially flat cooking element (10) is obtained. It is also noted, although this is not illustrated in [Fig.l], that the coating B could have been applied before the coating A.

[0261] As shown in [Fig.2], after shaping (step f)), a hollow cooking element (1) is obtained. Only a part of the peripheral part of the cooking element coated with coating B constitutes the side edge (or wall) or skirt of the hollow element (1), and has undergone shaping: the central part comprising only coating A and the other part of the peripheral part constitute the bottom of the hollow element (1).

[0262] [Fig. 3] schematically represents the manufacture of a coated cooking element (10') according to the invention according to a second architecture (overlapping layers). The metal support (20) in the form of a flat disc is provided (step a)), and comprises the face (2a) intended to be coated. The surface of the face (2a) has undergone or is undergoing a possible surface treatment (step b)) (not shown). A coating B is applied in a layer (5) which covers the entire face (2a), then a coating A is applied in a layer (8) in the central part (step c)). A heat treatment step is carried out (step e)). A substantially flat cooking element (10') is thus obtained.

[0263] As shown in [Fig.4], after shaping (step f)), a hollow cooking element (U) is obtained. Only a part of the peripheral part of the support, coated only with coating B, constitutes the side edge (or wall) or skirt of the hollow element (U), and has undergone shaping: the central part comprising coating A above a central part of coating B and the other part of the peripheral part constitute the bottom of the hollow element (U).

[0264] [Fig. 5] schematically represents a hollow cooking element (100) of architecture similar to that obtained by the method for obtaining [Fig. 1] (architecture of adjacent layers), with the sole difference that the coatings A and B are each two-layer. Thus, the coating A comprises two layers, a base layer (42) and a finishing layer (41) which may comprise a first decorative element (decor not shown). Similarly, the coating B comprises two layers, a base layer (52) and a finishing layer (51) which may comprise a second decorative element (decor not shown).

[0265] [Fig. 6] schematically represents a hollow cooking element (100') of architecture similar to that obtained by the method for obtaining [Fig. 3] (overlapping layer architecture), with the only difference that coatings A and B are each two-layer and that two-layer coating A covers more surface area since the forming was carried out substantially at the delimitation between coatings A and B. Thus, coating B comprises two layers, a base layer (54) and a finishing layer (53) which may comprise a first decorative element on the periphery (decor not shown). Similarly, coating A comprises two layers, a base layer (44) and a finishing layer (43) which may comprise a second decorative element (decor not shown).

[0266] [Fig.7] schematically represents a hollow cooking element (100”) of architecture similar to that of [Fig.6] (overlapping layer architecture), with the difference that the angle due to shaping, between the bottom and the lateral edge, is of a higher value, and that the coating B is three-layer. Thus, the coating B comprises three layers, a base layer (57), an intermediate layer (56) and a finishing layer (55), which may include a decorative element on the periphery (decor not shown). The coating A comprises the two layers (44) and (43).

[0267] In Figures 2 and 4 to 7, the coatings are present on the concave face.

[0268] The invention is illustrated in more detail in the following examples.

[0269] In these examples, unless otherwise indicated, all percentages and parts are expressed as mass percentages. EXAMPLES

[0270] Example 1: Coating A = sol-gel / coating B = polyester silicone -coatings A and B adjacent

[0271] This example is illustrated in [Fig.5].

[0272] The manufacture of a hollow coated cooking element 100 was carried out according to the following sequence of phases: 1. Supply of a flat aluminum disc with a thickness of 3.4 mm and a diameter of 340 mm. It is made of an annealed 4006 alloy. 2. Surface preparation by sandblasting. 3. Spray coating of a first layer 42 of coating A on a central area of ​​the disc, 35 pm thick and 205 mm in diameter. 4. Spray coating of the second layer 41 of coating A on the same central area of ​​the disc, 15 μm thick and 205 mm in diameter. 5. Tunnel drying up to 100°C for 5 min. 6. Screen-printing coating of a first layer 52 of coating B on the peripheral zone of the disc, in an adjacent layer relative to coating A, with a thickness of 17 μm and a width (ring) of 200 mm. 7. Tunnel drying up to 80°C for 5 min. 8. Screen-printing of a second layer 51 of coating B on the same peripheral area, with a thickness of 13 μm and a width (ring) of 200 mm. 9. Tunnel drying up to 80°C for 5 min. 10. Final cooking of the 2 coatings A and B in an oven at 250°C including a stage of 15 min. 11. Final shaping by stamping.

[0273] Step a) consists of phase L, step b) consists of phase 2., step c) consists of phases 3. to 9., and step e) consists of phase 10. Step f) consists of phase 10.

[0274] The compositions of coating layers A and B are given as follows.

[0275] The composition of the first layer 42 of coating A is as follows:

[0276] (% wet, total 100%).

[0277] [Tables2] Layer 1 (primer) % wet % baked colloidal silica 41 24 MTMS 29 27.6 Acetic acid 1 0 Pigment 15 30 inorganic filler 8 15.2 Isopropanol 3 0 Butyl glycol 1.4 0 Silicone oil 1.5 3 wetting agent 0.1 0.2 Total A+B+C 100 100

[0278] The composition of the second layer 41 of coating A is as follows:

[0279] (% wet, total 100%)

[0280] [Tables3] Layer 2 (Primer) % wet % cooked colloidal silica 35.00 41.4 Water 9.00 0 MTMS 37.00 53.9 Acetic acid 2.00 0 Isopropanol 8.30 0 Butyl glycol 7.10 0 Silicone oil 1.5 4.4 wetting agent 0.10 0.3 Total A+B+C 100.0 100.0

[0281] The composition of the first layer 52 of coating B is as follows:

[0282] (% wet, total 100%; % cooked, total 100%)

[0283] [Tables4] Chemical nature Role in the formula % wet % cured Ethoxy functionalized polyester silicone resin or Methoxy polyester silicone or Methyl Phenyl Silicone 1 or mix of 2 or 3 resins listed above Binders 30 59.6 Di propylene Glycol Butyl Ether Co-solvent 3 0 Fatty Acid Ester Additive (Wetting Agent) 3 0.5 Cr / Fe Oxide Pigment 10 33.1 Deionized Water Solvent 41.40 0 Fatty Alcohol Polyglycol Ether Additive (Emulsifier) ​​4.60 0.6 Mineral Oil Based Antifoam Additive (Antifoam) 2 0.7 Silica Additive 5 5 2-Amino-2-methyl-1-Propanol Additive (Buffering Agent) 0.5 0 Thickener Additive (Thickener) 0.5 0.5 TOTAL 100 100

[0284] The composition of the second layer 51 of coating B is as follows:

[0285] (% wet, total 100%; % cooked, total 100%)

[0286] [Tables5] Chemical Nature Role in Formula % Wet % Cured Polyester Silicone Resin Functional Ethoxy Resin (80% Silicone / 20% Polyester) Binders 35 91.5 Di Propylene Glycol Butyl Ether Co-solvent 6 0 Special Anionic Ester in Ethanol / Water Additive (Wetting Agent) 1 0.1 Mineral Oil Based Antifoam Additive (Antifoam) 1 0.4 Polyether Modified Polysiloxane Silicone Oil 0.5 2.2 Polydimethylsiloxane Fluid Silicone Oil 1 4.4 Deionized Water Solvent 50.50 0 Fatty Alcohol Polyglycol Ether Additive (Emulsifier) ​​4 0.7 2-Amino-2-Methyl-1-Propanol Buffering Agent 0.5 0 Acrylic thickener Additive (thickener) 0.5 0.7 TOTAL 100 100

[0287] Example 2: Coating A = sol-gel / coating B = thermoplastic(s) including PEEK - coatings A and B superimposed

[0288] This example is illustrated in [Fig.7].

[0289] The manufacture of a 100” hollow coated cooking element was carried out according to the following sequence of phases: 1. Supply of a flat aluminum bar with a thickness of 3.4 mm and a diameter of 340 mm. It is made of an annealed 4006 alloy. 2. Surface preparation: sandblasting. 3. Screen-printing of a first layer 55 of coating B over the entire disc, 10 μm thick. 4. Tunnel drying up to 50°C for 5 min. 5. Screen-printing of a second layer 54 of coating B over the entire disc, 10 μm thick. 6. Tunnel drying up to 50°C for 5 min 7. Screen-printing of a third layer 53 of coating B over the entire disc, 10 μm thick. 8. Tunnel drying up to 50°C for 5 min. 9. Bake coating B in an oven at 420°C for 15 minutes. 10. Spray coating of a first layer 42 of coating A on a central area of ​​the disc, 35 μm thick and 205 mm in diameter. 11. Spray coating of a second layer 41 of coating A on the same central area of ​​the disc, 15 μm thick and 205 mm in diameter. 12. Tunnel drying up to 100°C for 5 min. 13. Final cooking of the 2 coatings A and B in an oven at 250°C including a stage of 15 minutes. 14. Final shaping by stamping.

[0290] Step a) consists of phase L, step b) consists of phase 2., step c) consists of phases 3. to 12., and step e) consists of phase 13. Step f) consists of phase 14.

[0291] The compositions of the coating layers A were given in Example 1.

[0292] Each of the coating layers B has the same composition which is as follows:

[0293] (% wet, total 100%)

[0294] [Tableauxô] % wet % cooked PEEK (Poly Ether Ether Ketone) Aqueous Dispersion 70.5 79.5 MPG 9.5 — Wetting Agent 4.8 4.5 Mineral Oil Based Antifoam 1.9 5.3 Silica 9.5 8.1 Acrylic Thickener 2.9 2.6 Buffering Agent 0.9 — Total 100 100

Claims

Claims

1. Method for manufacturing a coated cooking element (10, 10'), characterized in that it comprises the following steps and in this order: a) Providing a metal support (2) in the form of a substantially flat disc (20) having a face (2a) intended to be coated; b) Optionally prior treatment of said face (2a) of said support; c) Application of at least one non-stick coating A (4; 8; 41, 42; 43, 44) and at least one coating B (3; 5; 51, 52; 53, 54; 57, 56, 55) on said face (2a) possibly treated with said support (2), B being different from A, neither A nor B comprising fluorocarbon resin, A covering only a central part of the support (2) in the form of a disc (4; 8) and B covering at least the peripheral part (3) of the disc (4) not covered by the coating A; d) Optional deposition of at least one additional layer of coating, in particular decorative or finishing;e) Heat treatment of the coated support after step c) or d) leading to obtaining the coated cooking element (10, 10'); and f) Shaping the coated cooking element (10, 10') resulting from step c), d) or e) to obtain a coated cooking element in a concave shape on said face (2a) (1, 1', 100, 100', 100”), defining a bottom (7, 70) and a lateral edge (6, 60) extending from the bottom (7, 70), the change in curvature between the bottom and the lateral edge being located in a part of the peripheral part (3, 5) of the support (2) coated with coating B.;

2. Method according to claim 1, such that the coating B covers (5) the entire support (2) below the coating A or such that the coating B covers the peripheral part (3) of the support (2) not covered by the coating A.

3. Method according to claim 1 or 2, such that the coating A comprises at least one material chosen from the following materials, alone or as a mixture: sol-gel compositions, polyarylether ketones (PAEK), aromatic thermoplastic polymers other than PAEK, thermoplastic polymers heterocyclic, and organopolysiloxane polymers; preferably coating A comprises a sol-gel composition.

4. Method according to one of claims 1 to 3, such that coating B comprises at least one material chosen from the following materials, alone or as a mixture: polyarylether ketones (PAEK), aromatic thermoplastic polymers other than PAEK, heterocyclic thermoplastic polymers, and organopolysiloxane polymers; preferably coating B comprises a polyarylether ketone or an aromatic thermoplastic polymer other than PAEK, even more preferably coating B is a polyether ether ketone (PEEK) or a polyether sulfone (PES).

5. Method according to one of claims 1 to 4, such that the pairs of coatings A and B are chosen from the following pairs (coating A; coating B): (sol-gel coating; ethoxy functionalized polyester silicone resin and / or methoxy polyester silicone and / or methyl phenyl silicone and / or methyl silicone), (sol-gel coating; polyether ether ketone PEEK and / or polyether sulfone PES).

6. Method according to one of claims 1 to 5, such that the coatings A and B are deposited in step c) in adjacent layers, the coating A being deposited only in the form of a disc in the center of the support (4; 41, 42), preferably according to a given radius, and the coating B being deposited on the peripheral part of the support (3; 51, 52) not covered by the coating A.

7. Method according to one of claims 1 to 5, such that coatings A and B are deposited in step c) in overlapping layers, coating B being deposited over the entire support (5; 53, 54; 55, 56, 57), then coating A being deposited in the center of the support (43, 44) in the form of a disc, preferably according to a given radius, above coating B.

8. Method according to one of claims 1 to 7, such that the coating A is two-layer or three-layer.

9. Method according to one of claims 1 to 8, such that the coating B is two-layer or three-layer.

10. Culinary article comprising a coated cooking element (1) obtained by the method according to one of claims 1 to 9.

11. Culinary article according to claim 10, chosen from the group consisting of saucepans, frying pans, skillets or fondue pots for fondue or raclette, casseroles, woks, sauté pans, crepe makers, grills, barbecue plates and grills, pots, casseroles, cooker bowls, bread machine bowls, waffle irons, barbecue plates and grills, baking pans and trays, and preparation bowls.

12. Electric cooking appliance comprising a cooking element coated (1) obtained by the method according to one of claims 1 to 9.

13. Electric cooking appliance according to claim 12, chosen in the group consisting of electric crepe makers, electric raclette machines, electric fondue machines, electric grills, electric griddles, electric cookers, bread machines, and electric pressure cooking appliances.

Images