Method for manufacturing coated cooking elements with mixed surfaces

Abstract

This invention relates to a method for manufacturing a coated cooking element having a mixed surface. The invention also relates to a cooking article or electric cooking appliance comprising a coated cooking element obtainable according to the method of this invention.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a coated cooking element having a hybrid surface. "Hybrid" can be understood as the coated cooking element comprising a substrate having at least two different coatings on the same surface. The invention also relates to a cooking article or electric cooking appliance comprising a coated cooking element obtainable according to the method of this invention. Background Technology

[0002] For many years, sol-gel coatings have been used to achieve non-stick coatings for cooking items. These coatings are called "sol-gel" because they are based on sol-gel chemistry. They are also referred to as "ceramics." This allows for the gradual replacement of coatings based on fluorocarbon resins such as polytetrafluoroethylene (PTFE). However, in industrial applications, sol-gel coatings are always applied to pre-formed items. In fact, the inorganic network that makes up the sol-gel coating will not deform without cracking. This deformation manifests as a significant reduction in adhesion to the substrate and less-than-ideal resistance to grease penetration in the case of use in cooking items. Therefore, sol-gel coatings cannot be applied using many planar coating techniques (screen printing, rollers, inkjet, curtains, etc.) and are typically applied by pneumatic spray guns. This results in significant product loss during spraying (depending on the shape of the part, the loss can be between 30% and 70% of the applied sol-gel formulation) and the problem of "overspraying" (i.e., unavoidable but undesirable spraying on the outside of the item), usually on the surface opposite the coated surface.

[0003] The situation is different with fluorocarbon coatings. Fluorocarbon coatings are deformable, especially stretchable, and can be deformed and shaped. Therefore, they are applied to a flat substrate by a planar coating process before heat treatment and then shaped.

[0004] To overcome these drawbacks, patent application WO2015 / 092332 describes a method in which an article is formed by a step of forming a metal part that has been previously coated with a sol-gel coating on at least one surface by means of a proper pre-cooling treatment of the sol-gel layer prior to molding.

[0005] However, this solution is complex and expensive to implement.

[0006] Therefore, it is still necessary to overcome these drawbacks so that it is possible to mold metal parts that have been previously coated with at least one sol-gel coating on at least one surface without significantly reducing the adhesion of the sol-gel coating to the substrate and exhibiting good resistance to grease penetration in the case of use in cooking items. Summary of the Invention

[0007] More specifically, the present invention proposes to realize a coated cooking element comprising a substrate having at least two different and overlapping coatings coated on the same surface, without complicating its manufacturing method, maintaining its basic properties, namely good strength, good durability and good cleanability, and having good mechanical properties in the overlapping area of ​​the coatings.

[0008] This invention relates to a method for manufacturing coated cooking elements, comprising the following steps in the following order: a) Provide a metal substrate (2) in the form of a substantially flat disk, the metal substrate (2) having a surface (2a) for coating. b) Apply coating A and coating B to the surface (2a); c) Perform heat treatment on the coated substrate (2) obtained after step b); in: - The coating B is different from the coating A; - The coating A covers only the central portion of the surface (2a) in the form of a disc, and the coating B covers at least the peripheral portion of the surface (2a) not covered by the coating A; - The coating A and the coating B overlap in the overlap region (X); - The coating A includes a layer A1, which includes a sol-gel material; - The coating B includes a layer B1, which comprises a material selected from aromatic thermoplastic polymers or heterocyclic thermoplastic polymers and organopolysiloxane polymers; - Layer A1 and layer B1 are in contact in the overlapping region (X); and - The layers A1 and B1 are applied as wet layers to wet layers, unless when the layer A1 is applied first and the layer B1 comprises an organopolysiloxane polymer, then step b) further includes the step of drying the layer A1 before applying the layer B1.

[0009] The present invention also relates to a cooking article or an electric cooking device, comprising a coated cooking element (1) that can be obtained by the method of the present invention.

[0010] definition In the context of this invention, a "cooking element" can be understood as an element capable of being heated and capable of transferring (or conducting) heat to an object in contact with the element. The heat (or thermal energy) is provided either through its own heating system, through an external heating system, or through contact with a previously heated element.

[0011] In the context of this invention, "cooking article" can be understood as a kitchen article used for cooking and capable of at least partially contacting food. For this purpose, the kitchen article is intended to undergo heat treatment.

[0012] The phrase "object for receiving heat treatment" should be understood in the context of this invention as an object that will be heated by an external heating system, such as a long-handled frying pan, a pan with handle, a frying pan, a stew pot, a wok, a grill plate or grill, a crepe maker, a double-handled lidded pot, a pressure cooker, a waffle maker, a grill, a mold and plate for pastry, a bread machine container, a cooking pot container, a preparation bowl, or a small frying pan or casserole dish with handle for cheese fondue or lacrete, and that the object is capable of transferring the heat energy provided by the external heating system to the material or food in contact with the object.

[0013] In the context of this invention, the term "electric cooking equipment" should be understood as a heated object having its own heating system, such as an electric crepe maker, a lacrete appliance, a cheese fondue appliance, an electric grill, an electric barbecue grill, an electric steamer, a bread maker, or a pressure cooking appliance.

[0014] In the context of this invention, a "coating" can be understood as a continuous layer, that is, a single, integral layer that forms a surface covering the entire plane of the desired surface. Such a coating can be a single layer or multiple layers, that is, it may include at least two layers.

[0015] In the context of this invention, "sol-gel coating" or "sol-gel material" can be understood as a coating or material synthesized from a solution based on a liquid-phase precursor via a sol-gel process, which is then transformed into a solid at low temperatures through a series of chemical reactions, particularly hydrolysis and condensation. The resulting coating or material can be either organic-mineral or entirely mineral-based.

[0016] In the sense of this invention, "organic-mineral coating (or material)" can be understood as a coating (or material) whose network is substantially inorganic but includes organic groups, especially due to the precursors used to achieve the coating (or material) and the baking temperature of the coating (or material) or due to the addition of organic fillers.

[0017] In the context of this invention, "completely mineral coating (or material)" can be understood as a coating (or material) composed of completely inorganic materials that do not contain any organic groups. Such a coating (or material) can be obtained by sol-gel at a baking temperature of at least 400°C, or from tetraethoxysilane (TEOS) type precursors at a baking temperature that can be lower than 400°C.

[0018] In the sense of this invention, “base layer” (or “bottom layer”) can be understood as all layers other than decoration and / or finish: from the first layer applied directly to the substrate to the last layer applied before the first decorative layer or before the first finish layer, when one of the first decorative layer and the first finish layer is present.

[0019] In the context of this invention, "decoration" or "decorative layer" can be understood as comprising one or more continuous or discontinuous layers of pigment composition. Decoration can be presented in the form of one or more patterns and one or more colors. Decoration is generally clearly visible to the naked eye and at normal usage distances of the article.

[0020] In the context of this invention, a "finishing layer" or "final coating" can be understood as a continuous and most often transparent surface layer. The finishing layer protects any underlying layer from mechanical damage and imparts its anti-adhesive properties to the coating. The finishing layer is intended to come into contact with food in cases where it is used in food applications.

[0021] In the context of this invention, "overlapping layer" can be understood as a partially or completely overlapping layer.

[0022] In the context of this invention, "wet layer" can be understood as a layer comprising all or part of its solvent. In other words, it is understood that the layer of interest has neither undergone drying nor baking after its application.

[0023] In the context of this invention, "alkyl" can be understood as a straight-chain or branched saturated monovalent hydrocarbon chain that typically comprises 1 to 10, preferably 1 to 6, carbon atoms. Examples include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, or pentyl.

[0024] In the context of this invention, "alkoxy" can be understood as an alkyl group as defined above, which is attached to the remainder of the molecule by an oxygen atom. Examples include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, or n-pentoxy.

[0025] In the context of this invention, "aryl" can be understood as an aromatic hydrocarbon group preferably comprising 6 to 10 carbon atoms and including one or more coupled rings, such as phenyl or naphthyl. Advantageously, it is phenyl.

[0026] In the context of this invention, "alkenyl" can be understood as a hydrocarbon chain comprising at least one terminal or chain that is doubly unsaturated and preferably comprises 6 to 10 carbon atoms, such as vinyl or allyl.

[0027] In the context of this invention, "alkynyl group" can be understood as a hydrocarbon chain comprising at least one terminal or chain triple unsaturation and preferably containing 6 to 10 carbon atoms.

[0028] In the context of this invention, the term "D50" can be understood as the maximum size of 50% of the particles.

[0029] In the context of this invention, the term "D90" can be understood as the maximum size of 90% of the particles.

[0030] According to the present invention, "X and / or Y" can be understood as either X, or Y, or X and Y.

[0031] Detailed description of the invention Manufacturing method This invention relates to a method for manufacturing coated cooking elements (1), comprising the following steps in the following order: a) Provide a metal substrate (2) in the form of a substantially flat disk, the metal substrate (2) having a surface (2a) for coating. b) Apply coating A and coating B to the surface (2a); c) Perform heat treatment on the coated substrate (2) obtained after step b); in: - The coating B is different from the coating A; - The coating A covers only the central portion of the surface (2a) in the form of a disc, and the coating B covers at least the peripheral portion of the surface (2a) not covered by the coating A; - The coating A and the coating B overlap in the overlap region (X); - The coating A includes a layer A1, which includes a sol-gel material; - The coating B includes a layer B1, which comprises a material selected from aromatic thermoplastic polymers or heterocyclic thermoplastic polymers and organopolysiloxane polymers; - Layer A1 and layer B1 are in contact in the overlapping region (X); and - The layers A1 and B1 are applied as wet layers to wet layers, unless when the layer A1 is applied first and the layer B1 comprises an organopolysiloxane polymer, then step b) further includes the step of drying the layer A1 before applying the layer B1.

[0032] The method according to the invention may optionally include an additional step of pretreating the surface (2a) of the substrate (2) between step a) and step b). This step is optional, especially if a metal substrate (2) is provided in step a) and the metal substrate (2) has already been pretreated on its surface (2a) for coating.

[0033] In this pretreatment step, the surface (2a) of the metal substrate (2) to which the coating is to be applied may undergo a surface treatment that allows for improved adhesion of one or more coatings to the substrate (2), for example by sandblasting, degreasing, chemical stripping, etc. The substrate (2) and the surface treatment are described in detail below.

[0034] Step b) of applying coating A and coating B is performed after step a) or after step a) and the pretreatment step.

[0035] Any layer of the coating is typically applied in a wet form. In fact, the formulation of the layer to be coated may be aqueous or may include at least one solvent, typically a polar protic solvent or a polar aprotic solvent, such as an ester or amide. This solvent may be non-toxic. The solvent may advantageously include at least one alcohol, and may preferably be selected from isopropanol, methanol, ethanol, and mixtures thereof. All or part of the solvent in the wet layer may be removed during or at the end of the process, either naturally or by physical treatment, such as by thermal drying, air drying, or vacuum treatment.

[0036] Unless otherwise specified, particularly with regard to the application of coatings A and B for contact, these layers may be applied as wet layers to wet layers, or may be applied between the application of some or all layers, in which case they may be applied as wet layers to dry layers.

[0037] Therefore, unless otherwise stated, any layer application step can advantageously be followed by a drying step, as is known to those skilled in the art. Advantageously, the manufacturing method according to the invention includes one or more drying steps between 70°C and 150°C after applying each layer or only certain layers. Drying can be carried out, for example, by convection or infrared (IR).

[0038] The layers of coating A and coating B obtained according to the invention are advantageously solid after drying. According to the invention, "solid" can be understood as the property of a viscous material that is insoluble in water, common solvents, and food components such as aqueous or fatty mixtures, even if the material may have high hardness or high flexibility (e.g., an elastomer).

[0039] According to the present invention, when the layer of coating B comprises a thermoplastic polymer and is used to contact the layer of coating A in the overlap region (X), the layer is applied in the form of wet layer to wet layer.

[0040] Therefore, according to one embodiment of the present invention, when the layer B1 comprises an aromatic thermoplastic polymer or a heterocyclic thermoplastic polymer, the layer A1 and the layer B1 are applied in the form of a wet layer to a wet layer.

[0041] According to the present invention, when the layer of coating B comprises an organopolysiloxane polymer and is used to contact the layer of coating A in the overlap region (X) and is applied before the layer of coating A, the layer is applied in the form of a wet layer on a wet layer.

[0042] Therefore, according to one embodiment of the present invention, when layer B1 comprises an organopolysiloxane polymer and is applied first, layer A1 and layer B1 are applied in the form of wet layer to wet layer.

[0043] According to the present invention, when the layer of coating B comprises an organopolysiloxane polymer and is used to contact the layer of coating A in the overlap region (X) and is applied after the layer of coating A, the layer of coating A is dried before the layer of coating B is applied.

[0044] Therefore, according to another embodiment of the invention, when the layer B1 comprises an organopolysiloxane polymer and is applied after the layer A1, step b) further includes the step of drying the layer A1 before applying the layer B1.

[0045] The following describes coating A and coating B and their structure in detail.

[0046] The method according to the invention may further include the step of applying at least one layer, particularly a decorative and / or finishing layer, onto coatings A and B between step b) of applying coatings A and B and the heat treatment step c). This step is well known to those skilled in the art.

[0047] The heat treatment step c) of coating the substrate (2) allows the layers applied to the substrate (2) to be densified. This step is also referred to in some cases as a baking step or a sintering step. This step is performed after step b). This step is usually performed simultaneously on all applied layers. This embodiment allows all layers to be filmed, merged and crosslinked with each other, so that they form only one layer. Thus, the coating of the substrate (2) forms a single layer, even if the single layer is not homogeneous, i.e., the single layer has heterogeneity in composition and / or structure.

[0048] According to one embodiment, heat treatment step c) is carried out at a temperature between 230°C and 430°C, preferably between 230°C and 300°C.

[0049] Advantageously, the method according to the invention may also include a step of shaping the coated substrate (2). This step allows the properties of coating A for the substrate, especially the mechanical properties, to be maintained, while allowing shaping to be performed after coating A and coating B are applied, since coating B is chosen to be more deformable than coating A and therefore able to undergo shaping without cracking.

[0050] Forming is also known as stamping. This allows for the final shape of a hollow coated cooking element, which typically has an inner surface capable of holding food and an outer surface for placement on the heat source side. The inner surface is equipped with coatings A and B, and forming is performed by deforming a portion of the cooking element that includes coating B but does not include coating A.

[0051] According to the present invention, a “hollow element” can be understood as an element having a concave shape on the coated or uncoated surface (2a) of the substrate (2).

[0052] According to one embodiment, the curvature change caused by molding occurs in the demarcation zone between the overlapping area and coating B. In other words, the central portion and the overlapping area constitute the bottom of the hollow coated cooking element, and the peripheral portion constitutes the side edges (or skirt) of the hollow coated cooking element.

[0053] According to another embodiment, the curvature change caused by molding occurs in a portion of a coated cooking element that includes only coating B and not coating A. In this case, preferably, a portion of the central portion, the overlapping area, and optionally a portion of the peripheral portion constitutes the bottom of the hollow coated cooking element, and another portion of the peripheral portion constitutes the side edge (or skirt) of the hollow coated cooking element.

[0054] The possibility of forming cooking elements coated with coatings A and B using the method according to the invention offers numerous advantages, both industrially and aesthetically, in terms of the potential for creating hollow cooking elements and thus articles containing such hollow cooking elements.

[0055] Therefore, using the method according to the invention, it is possible to perform the application steps b) of coating A and coating B using planar coating techniques. These planar coating techniques allow for significant savings in coating consumption from an industrial perspective on the one hand, and eliminate the problem of spraying (or “over-spraying”) on the outside of components on the other hand.

[0056] Aesthetically, applying coatings A and B using planar coating techniques is also highly advantageous, as these techniques offer greater decorative possibilities. In fact, creating decorations on a flat plate (through flexographic printing, roller printing, inkjet printing, or using multi-layer screen printing, etc.) is much easier than using spraying techniques (which require the use of a covering) or inserting decorations on the bottom of an item via pad printing.

[0057] Furthermore, processing the flat metal before applying the coating simplifies the optional step of pretreating the surface (2a) of the substrate (2) for coating.

[0058] Finally, this method allows for the production of coated cooking elements with good anti-adhesion properties, even in the absence of fluorocarbon resin.

[0059] structure Each of coating A and coating B according to the invention comprises one or more layers applied to a substrate (2). Coating A comprises at least one layer A1, and coating B comprises at least one layer B1, wherein layer A1 and layer B1 are in contact.

[0060] Therefore, coating A can be a single layer (i.e., formed by a single layer) or multiple layers (i.e., formed by at least two layers). According to a preferred embodiment, coating A can be a double layer (i.e., formed by two layers) or a triple layer (i.e., formed by three layers). All layers of coating A can have the same composition. All layers of coating A can also have compositions that are different from each other.

[0061] Similarly, coating B can be a single layer (i.e., formed by a single layer) or multiple layers (i.e., formed by at least two layers). According to a preferred embodiment, coating B is a double or triple layer. All layers of coating B may have the same composition. All layers of coating B may also have compositions that differ from each other.

[0062] When coating A or coating B is multilayered, the different layers of the coating are applied sequentially.

[0063] It is possible that coating A or coating B includes at least one intermediate layer, preferably two intermediate layers, which may be decorative layers.

[0064] According to one embodiment, the decorative layer is continuous and covers the entire surface of the substrate (2), regardless of the layer on which it is applied. According to another embodiment, the decorative layer does not cover the entire substrate and forms at least one decoration.

[0065] It is possible that coating A or coating B includes at least one finishing layer. The finishing layer may cover the entire surface of the substrate, regardless of the layer in which it is applied. Preferably, each of coating A and coating B includes a finishing layer, and the two finishing layers are different from each other.

[0066] The central and peripheral portions of the substrate (2) are generally complementary to correspond to the entire surface of the substrate (2). Therefore, according to the invention, the surface (2a) of the substrate (2) is coated with a coating A in the form of a disc in its central portion and with a coating B at least in its peripheral portion which is not coated with coating A.

[0067] According to the present invention, coating A and coating B overlap in the overlap region (X). According to the present invention, the "overlap region" can be understood as the area where some or all of the layers of coating A and coating B overlap each other.

[0068] According to one implementation, “coating A and coating B overlap” means that all layers of coating A overlap with all layers of coating B in the overlap region (X), or conversely, all layers of coating B overlap with all layers of coating A in the overlap region (X).

[0069] According to another embodiment, “coating A and coating B overlap” means that at least one layer of coating A overlaps with at least one layer of coating B in the overlap region (X), or conversely, at least one layer of coating B overlaps with at least one layer of coating A in the overlap region (X).

[0070] According to a first embodiment of the invention, coating A and coating B are applied as partially overlapping layers in step b). In this embodiment, coating A preferably exists along a given radius at the center of the surface (2a) of the substrate (2) in the form of a disk, and coating B exists on at least a portion of the disk not covered by coating A and on a portion of the central portion of the surface (2a) covered by coating A. Preferably, according to a particular embodiment of this first embodiment of the invention, in the overlapping area (X): - All layers of coating A overlap with all or some layers of coating B; or - All layers of coating B overlap with all or some layers of coating A; or - All layers of coating A overlap with some layers of coating B, and the other layers of coating B overlap with all layers of coating A; or - All layers of coating B overlap with some layers of coating A, and the other layers of coating A overlap with all layers of coating B; or - Some layers of coating A overlap with some layers of coating B, and other layers of coating B overlap with some layers of coating A; or - Some layers of coating B overlap with some layers of coating A, and other layers of coating A overlap with some layers of coating B.

[0071] In this first embodiment, the overlapping region (X) has a ring shape. Preferably, according to this first embodiment of the invention, the overlapping region (X) is a ring with a width greater than 0 mm and less than or equal to 10 mm, and even more preferably between 0.1 mm and 10 mm.

[0072] According to a second embodiment of the invention, coatings A and B are applied in step b), with each layer either completely or partially overlapping. In this embodiment, coating A preferably exists along a given radius at the center of the surface (2a) of the substrate (2) in the form of a disk, coating B exists on at least a portion of the disk not covered by coating A, and all or some layers of coating B exist in the entire central portion of the surface (2a) below coating A. Preferably, according to a particular embodiment of this second embodiment of the invention, in the overlapping area (X): - All layers of coating A overlap with all or some layers of coating B; or - All layers of coating A overlap with some layers of coating B, and other layers of coating B overlap with all or some layers of coating A; or - All layers of coating A overlap with some layers of coating B, and some other layers of coating B overlap with some layers of coating A and are also overlapped by other layers of coating A; or - All layers of coating A overlap with some layers of coating B, and some layers of coating A also overlap with some other layers of coating B and are overlapped by other layers of coating B.

[0073] In this second embodiment, the overlapping area (X) has a disk shape, preferably having the same radius as the disk formed by coating A.

[0074] Within the scope of this invention, coating A includes layer A1, which includes a sol-gel material, and coating B includes layer B1, which includes a material selected from aromatic thermoplastic polymers or heterocyclic thermoplastic polymers and organopolysiloxane polymers.

[0075] Within the scope of this invention, layer A1 and layer B1 are in contact in the overlap region (X).

[0076] The materials of coating A and coating B have very different properties. However, the method according to the invention, particularly the step in which coating A and coating B are applied to each other, allows for increased mechanical strength of the coatings in the overlap region (X). Tearing and / or peeling in this overlap region (X) are reduced.

[0077] metal substrate The metal substrate provided in step a) according to the present invention is typically made of aluminum, stainless steel, cast iron, or cast aluminum, iron, titanium, copper, or a mixture thereof.

[0078] In the context of this invention, “aluminum” can be understood as a metal composed of 100% aluminum or aluminum alloys.

[0079] Advantageously, the metal substrate is a substrate made of aluminum or stainless steel, or a multilayer metal substrate on which the coating is to be applied is made of aluminum alloy or stainless steel. Preferably, the metal substrate comprises alternating metal layers and / or metal alloy layers. More preferably, the metal substrate is an aluminum substrate.

[0080] The metal substrate can be a two- or three-layer substrate, and these multilayers can be obtained, for example, by lamination, by thermal diffusion under load (“solid-state bonding”), or by thermal or cold shock (“shock bonding”).

[0081] Advantageously, the thickness of the metal substrate is between 0.5 mm and 10 mm.

[0082] According to one embodiment, the surface of the metal substrate to which the coating is to be applied has undergone a surface treatment, which is a combination of various techniques such as chemical etching, brushing, hydration, sandblasting, shot peening, plasma or corona or laser physicochemical treatment, chemical activation, or chemical activation.

[0083] Advantageously, the surface of the substrate to which the coating is to be applied can be treated to increase its specific surface area; for aluminum substrates, the coating can be applied by techniques such as anodizing (forming a tubular alumina structure), chemical etching, sandblasting, brushing, shot peening, or thermal spraying (flame, plasma, or arc spraying). Other metal substrates can also be treated by techniques such as polishing, sandblasting, brushing, microbead blasting, or thermal spraying (flame, plasma, or arc spraying) to accept the addition of materials.

[0084] Advantageously exemplified as surface-treated metal substrates that can be used in this invention are: aluminum substrates that are anodized or non-anodized, optionally polished, brushed, sandblasted, shot-peened, or microbead-peened; aluminum alloy substrates that are anodized or non-anodized, optionally polished, brushed, sandblasted, or microbead-peened; steel substrates that are optionally polished, brushed, sandblasted, shot-peened, or microbead-peened; stainless steel substrates that are optionally polished, brushed, sandblasted, or microbead-peened; cast steel, cast aluminum, or cast iron substrates; and copper substrates that are optionally forged or polished.

[0085] According to one embodiment, the surface of the metal substrate to be coated has undergone a surface treatment, which is a combination of various techniques such as chemical etching, brushing, hydration, sandblasting, shot peening, plasma or corona or laser physicochemical treatment, chemical activation, or chemical activation.

[0086] Advantageously, the substrate can be selected from: substrates including ferritic stainless steel / aluminum / austenitic stainless steel layers, substrates including stainless steel / aluminum / copper / aluminum / austenitic stainless steel layers, cast aluminum, aluminum or aluminum alloy substrates with an inner stainless steel outer bottom, metal laminate substrates, such as bilayer laminate substrates including a stainless steel layer (e.g. for constituting the inner surface of an article) and an anodized or non-anodized aluminum or aluminum alloy layer (e.g. for constituting the outer surface of an article).

[0087] Advantageously, the average arithmetic roughness Ra of the surface of the metal substrate to which the coating is to be applied is greater than or equal to 1 μm.

[0088] The average arithmetic roughness Ra is measured using a roughness meter according to standard ISO 4287. Ra represents the arithmetic mean of the average deviations. Surface topography can be studied, in particular, using a profilometer with a detector equipped with a fine stylus fitted with a diamond tip, or also using an Altisurf® type optical metrology device, in which a color confocal sensor allows for non-contact measurement. The study of this surface topography allows for the determination of the average arithmetic roughness Ra.

[0089] coating Preferably, the coating according to the invention does not contain fluorocarbon resin. According to one embodiment, coating A and / or coating B do not contain fluorocarbon resin.

[0090] Advantageously, the coating A obtained according to the invention is an anti-stick coating, meaning that food will not substantially adhere to the coating.

[0091] Advantageously, coating B has greater deformability than coating A, and the deformability is measured either according to standard NF EN ISO 1519 or according to standard NF EN ISO 1519 applicable to coatings inside folds.

[0092] Typically, materials can be characterized by a curve (C), which gives the stress σ (Pa) as a function of deformation (ε), such as... Figure 10 As shown. As those skilled in the art will know, the three zones are identifiable: elastic deformation (C1), plastic deformation (C2), and fracture zone (R).

[0093] In the presence of a coating on a substrate, the coating is considered "deformable" as long as it remains within its elastic or plastic deformation zone. Direct measurement of the coating is complex, and this "deformability" is quantified using standard NF EN ISO 1519 or standard NF EN ISO 1519 applicable to coatings located inside folds.

[0094] The NF EN ISO1519 standard specifies an empirical test method that allows for the evaluation of the crack resistance and / or peel resistance of paint, varnish or similar product layers on metal or plastic substrates when folded on a cylindrical mandrel under standardized conditions.

[0095] According to a preferred embodiment, coating A includes at least one layer A1, which comprises a sol-gel material. This composition constitutes a continuous phase of coating A.

[0096] According to one embodiment, coating A is multilayered, comprising layers A1 and A2, wherein layer A1 comprises a sol-gel material, and layer A2 comprises a sol-gel material. The materials of layers A1 and A2 may be the same or different. The sol-gel material constitutes a continuous phase of coating A.

[0097] Advantageously, coating A includes layer A1, which is composed of the following: - At least one sol-gel material; - At least one type of filler; - At least one colorant; and - At least one additive.

[0098] According to a preferred embodiment, coating B includes at least one layer B1, which comprises a material selected from aromatic thermoplastic polymers or heterocyclic thermoplastic polymers and organopolysiloxane polymers. This material constitutes a continuous phase of coating B.

[0099] According to one embodiment, coating B is multilayered and includes layers B1 and B2 as defined above. Layer B2 comprises a material selected from aromatic thermoplastic polymers or heterocyclic thermoplastic polymers, organopolysiloxane polymers, and mixtures thereof. The materials of layers B1 and B2 may be the same or different. The materials constitute a continuous phase of coating B.

[0100] Preferably, the aromatic thermoplastic polymer of layer B1 and, if necessary, the aromatic thermoplastic polymer of layer B2 are selected from polyaryletherketone (PAEK), poly(phenylene ether) (PPO), polyarylether sulfone (PAES), especially polyethersulfone (PES), polyphenylene ether sulfone (PPSU), polyphenylene sulfide (PPS), poly(arylene sulfide) (PAS), liquid crystal polymers, and mixtures thereof.

[0101] Preferably, the organopolysiloxane polymer of layer B1 and, if necessary, the organopolysiloxane polymer of layer B2 are selected from methyl silicone resin and / or phenyl silicone resin and / or methylphenyl silicone resin, methyl silicone polyester resin (copolymer), phenyl silicone polyester resin (copolymer), methylphenyl silicone polyester resin (copolymer), silyl alkyd resin (copolymer), modified silicone resin, and mixtures thereof.

[0102] Advantageously, coating B includes layer B1, which is composed of the following: - At least one aromatic thermoplastic polymer or heterocyclic thermoplastic polymer or at least one organopolysiloxane polymer; - At least one type of filler; - At least one colorant; and - At least one additive.

[0103] continuous phase The continuous phase is an important component of the coating. Typically, the coating includes at least 20% by weight of the continuous phase relative to the total weight of the coating in the wet state. By extension, this means that other components (typically fillers and / or additives and / or colorants) that do not substantially affect the inherent properties of the coating may be present, and these other components are typically present in the wet state at most 50% by weight relative to the total weight of the coating.

[0104] Sol-gel (SG) Sol-gel materials are either organic-mineral or entirely mineral-based. Materials synthesized from metal polyalkoxylate-type precursors via sol-gel processes possess a hybrid network, typically silica with grafted alkyl groups. Sol-gel formulations that allow the production of sol-gel materials generally comprise at least one colloidal metal oxide and at least one metal alkoxide-type precursor.

[0105] The metal oxide is preferably a colloidal metal oxide selected from colloidal silica and / or colloidal alumina and / or colloidal zirconium or / or colloidal titanium.

[0106] Preferably, a metal alkoxide selected from the group consisting of: - Corresponds to the general formula M1(OR1) n The precursor, - Corresponds to the general formula M2(OR2) (n-1) R 2’ The precursor, - Corresponds to the general formula M3(OR3) (n-2) R 3’ The precursor of, wherein: R1, R2, R3 or R 3’ Indicates alkyl group, R 2’ Indicates alkyl, aryl, alkenyl, or alkynyl, such as phenyl, vinyl, or allyl. n is an integer corresponding to the maximum valence of metals M1, M2, or M3. M1, M2, or M3 represent metals selected from Si, Zr, Ti, Sn, Al, Ce, V, Nb, Hf, Mg, or Ln.

[0107] Advantageously, the metal alkoxide is an alkoxysilane.

[0108] Examples of alkoxysilanes that can be used in the methods of the present invention include, in particular, methyltrimethoxysilane (MTMS), tetraethoxysilane (TEOS), methyltriethoxysilane (MTES), dimethyldimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, and mixtures thereof.

[0109] Preferably, alkoxysilanes MTES and TEOS are used because they have the advantage of not containing methoxy groups. In fact, the hydrolysis of methoxy groups leads to the formation of methanol in sol-gel formulations, which requires additional precautions during application given their toxicity classification. On the other hand, the hydrolysis of ethoxy groups only produces ethanol, which has a more favorable classification and therefore less restrictive usage regulations.

[0110] The formation of the sol-gel material involves mixing an aqueous composition X comprising colloidal metal oxides and a solution Y comprising metal alkoxides. This mixing is advantageously carried out at a ratio of 40% to 75% by weight of the aqueous composition relative to the weight of the sol-gel formulation (X+Y), such that the amount of colloidal metal oxides is 5% to 50% by weight of the dry sol-gel formulation (X+Y).

[0111] The aqueous composition X may also include a solvent, particularly a solvent comprising at least one alcohol.

[0112] The aqueous composition X may also include at least one silicone oil.

[0113] The aqueous composition X may also include pigments.

[0114] The aqueous composition X may also include mineral fillers.

[0115] The aqueous composition X may also include pyrolytic silica, which functions to adjust the viscosity of the sol-gel composition and / or the gloss of the dry coating.

[0116] Solution Y may also include Brönsted acid or Lewis acid. Advantageously, the metal alkoxide precursor of solution B is mixed with a mineral-organic Lewis acid comprising 0.01% to 10% by weight of the total weight of solution Y.

[0117] Specific examples of acids that can be used to mix with metal alkoxide precursors are acetic acid, citric acid, hydrochloric acid, or formic acid.

[0118] Solution Y may also include a solvent, particularly a solvent comprising at least one alcohol.

[0119] Solution Y may also include at least one silicone oil.

[0120] Solution Y may also include metallic flakes.

[0121] According to an advantageous embodiment of the method of the present invention, solution Y may comprise a mixture of one of the alkoxysilanes as defined above and an aluminum alkoxide.

[0122] Aromatic thermoplastic polymers PAEK Polyaryletherketone (PAEK) is generally selected from the group consisting of: polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetheretherketoneketone (PEEKK), and polyetherketoneetherketoneketone (PEKEKK). Preferably, PAEK is PEEK or PEKK. Even more preferably, PAEK is PEEK.

[0123] Unlike PAEK, aromatic thermoplastic polymers Aromatic thermoplastic polymers that differ from PAEK are typically selected from poly(phenylene ether) (PPO), polyarylene ether sulfone (PAES), and especially polyether sulfone (PES), polyphenylene ether sulfone (PPSU), polyphenylene sulfide (PPS), poly(arylene sulfide) (PAS), liquid crystal polymers and mixtures thereof.

[0124] The aromatic thermoplastic polymers that differ from PAEK preferably include PES or PPS. Even more preferably, the aromatic thermoplastic polymers that differ from PAEK are PES.

[0125] An amorphous, non-crystalline aromatic thermoplastic polymer such as PPSU / PES allows for improved film formation of the coating because its glass transition temperature is much lower than the melting temperature of PAEK, which improves adhesion to the substrate. This also advantageously allows for increased ductility of the material and promotes its stretchability and stamping capabilities.

[0126] Heterocyclic thermoplastic polymers Heterocyclic thermoplastic polymers are typically selected from polyetherimide (PEI), polyimide (PI), polyamideimide (PAI), and polybenzimidazole (PBI).

[0127] Organopolysiloxane polymers In the text of the specification, the terms "silicone resin" and "organopolysiloxane polymer" may be used interchangeably to refer to silicon before or after its crosslinking. In the text of the specification, the term "silicone" refers to an organopolysiloxane material. Crosslinking is a step that allows silicon to be transformed into an insoluble material, for example, through addition polymerization, condensation polymerization, or dehydrogenation. Crosslinking occurs from precursors, typically silicone oils or silicone resins, which are crosslinked to obtain a three-dimensional network that forms a material referred to as a silicone resin or organopolysiloxane polymer.

[0128] This crosslinking can be achieved through thermal activation or chemical activation with the aid of a catalyst such as platinum.

[0129] Silicone resins can be obtained from precursors and are advantageously soluble in emulsions in solvents or water, such as oils or crosslinkable resins, particularly selected from: hydrides, silicone oil resins comprising at least one vinyl group (-CH=CH2), silicone resins or silicone polyester resins (copolymers) comprising at least one alkoxy group, such as a methoxy group or an ethoxy group, and / or silicone resins or silicone polyester resins (copolymers) comprising at least one alkoxy group, particularly an ethoxy group or a hydroxyl group, and mixtures thereof. These precursors have the ability to crosslink in order to obtain a silicone resin characterized by its insolubility and its substantially solid form.

[0130] Advantageously, these precursors are polymeric or oligomeric, either in the form of silicone oils with variable branching, or in the form of silicone resins or silicone copolymers with variable pre-crosslinking, such as silicone polyester resins, silicone alkyd resins, silicone polyurethane resins, silicone epoxy resins, or in the form of mixtures of silicone oils, silicone resins, and silicone copolymers. Silicon atoms may be substituted with alkyl (especially methyl) or aryl (especially phenyl) groups or mixtures thereof. The oil or resin preferably includes one or more (2, 3, or more) hydroxyl or alkoxy (especially methoxy, ethoxy, butoxy) functional groups as substituents for the silicon atoms.

[0131] Advantageously, one or more silicone resins, in the case of crosslinking after their precursors are crosslinked, are selected from the group consisting of methyl silicone resins and / or phenyl silicone resins and / or methylphenyl silicone resins, methyl silicone polyester resins (copolymers), phenyl silicone polyester resins (copolymers), methylphenyl silicone polyester resins (copolymers), silyl alkyd resins (copolymers), modified silicone resins, and mixtures thereof.

[0132] Advantageously, one or more silicone resins are selected from the group consisting of methyl silicone resins and / or phenyl silicone resins and / or methylphenyl silicone resins, methyl silicone polyester resins (copolymers), phenyl silicone polyester resins (copolymers), methylphenyl silicone polyester resins (copolymers), silyl alkyd resins (copolymers), modified silicone resins, and mixtures thereof.

[0133] Silicone resins form a network that can be composed of a combination of four simple organosiloxane units, designated M, D, T, and Q according to the degree of oxygen substitution of silicon, as shown in the table below, where R is an organic substituent as described below.

[0134] [Table 1] Organopolysiloxane materials or polymers are obtained from precursors through crosslinking. These precursors can be monomeric or polymeric, or oligomers as intermediates. Organopolysiloxane polymers can also be obtained from mixtures of these different types of precursors. The crosslinking density is higher when the network contains a higher number of T and Q units than D. The distribution among M, D, T, and Q units depends on the chemical structure of the precursors, and particularly on this distribution of M, D, T, and Q within the precursors.

[0135] The polymer precursors are organopolysiloxanes. These macromolecules are formed from the M, D, T and / or Q units described in the table, wherein R is independently an alkyl group, particularly methyl, or an aryl group, particularly phenyl, and different properties of R can exist on the same macromolecule.

[0136] Organopolysiloxanes can be linear or slightly branched (mostly D-groups), or branched or highly branched (mostly T and Q-groups). Linear or slightly branched organopolysiloxanes are typically liquids, more or less viscous at room temperature, and are referred to as silicone oils. Branched or highly branched (pre-crosslinked) organopolysiloxanes form a network of individual macromolecules and are referred to as silicone resins. At room temperature, the resins are essentially solid or liquid, especially under conditions of relatively low molecular weight, in solution form in a solvent or as an aqueous emulsion. These resins can be copolymerized with non-silicone organic polymers or oligomers, particularly selected from polyesters, acrylics, alkyds, polyurethanes, and epoxy resins.

[0137] When crosslinking is hydrolysis-condensation: this is due to the presence of reactive hydroxyl or alkoxy functional groups, especially methoxy, ethoxy, or butoxy functional groups, on the organopolysiloxane.

[0138] When crosslinking is addition polymerization (or hydrosilanization): this is carried out by a reaction between a reactive vinyl functional group (-CH═CH2) present on one of the organopolysiloxanes and a reactive hydromethionide functional group (Si-H) present on another organopolysiloxane mixed with the first.

[0139] All these reactive functional groups are present on each organopolysiloxane in at least one quantity, and may be present in quantities of two, three or more, within the limits allowed by the molecular structure. Silicone oils containing at least one reactive functional group are called "reactive oils". Reactive functional groups may be located at the ends (terminals) of the macromolecular chain or distributed throughout the entire chain.

[0140] Silicone polyester resins are particularly characterized by silicone / polyester mass ratios, such as 90 / 10, 80 / 20, 70 / 30, 60 / 40, 50 / 50, 40 / 50, 30 / 70, 20 / 80, and 10 / 90, with an advantage between 80 / 20 and 50 / 50.

[0141] Linear PDMS silicone oils, pure or pre-emulsified in water, are characterized firstly by their molecular weight, which changes directly with increasing viscosity of the pure oil. These silicone oils are then characterized by the presence of reactive functional groups, such as hydroxyl functional groups on silicon atoms (silanols), their number, and their positions on the molecular chain. For example, reactive oils with viscosities between 50 mPa·s and 20,000 mPa·s, and particularly between 300 mPa·s and 5,000 mPa·s, can be used. These reactive oils have at least one reactive functional group, preferably at least two, which can be located at the chain ends.

[0142] Polymer precursors obtained by addition polymerization may include, for example, polymethylhydrosiloxanes, vinylmethylsiloxanes, particularly linear vinyl-terminated polydimethylsiloxanes (PDMS), vinyl-terminated diphenylsiloxane-dimethylsiloxane copolymers, hydride-terminated polydimethylsiloxanes, hydride-terminated polyphenylmethylsiloxanes, cyclic vinylmethylsiloxanes, vinyl MQ resins, trimethylsilyl-terminated polymethylsiloxanes, trimethylsiloxane-terminated methylhydrosiloxane and dimethylsiloxane copolymers, resin hydrides MQ, and combinations thereof.

[0143] Polymer precursors obtained through hydrolysis-condensation reactions, whether silicone resins or silicone oils, may include, for example: poly(methylsilsesquioxane), poly(propylsilsesquioxane), poly(phenylsilsesquioxane), 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-acetoxyethylsiloxane), organically modified alkoxysilanes and their oligomers, and all similar macromolecules and mixtures thereof.

[0144] Organopolysiloxane materials or polymers can also be obtained by crosslinking one or more monomer precursors and one or more polymer precursors as described above, and a mixture of one or more oligomer precursors that may be linear, branched, or cyclic. These oligomer precursors have a lower molecular weight than the polymer precursors. Polymer precursors and / or oligomer precursors comprising more than two, advantageously much more than two, reactive functional groups as described above can be added to the mixture as "co-adhesives" to promote a high crosslinking density of the final organopolysiloxane polymer.

[0145] Monomer precursors, oligomer precursors, and / or polymer precursors, particularly silicone resins, whether or not copolymerized with organic polymers, act as polymer adhesives to obtain solid organopolysiloxane polymers bonded to each layer of thermoplastic plastic.

[0146] Silicone oil-based organopolysiloxane precursors, if added in small amounts (typically between 0.1% and 5% by dry weight) throughout a single-layer formulation, can be considered additives, independent of other components used to form solid organopolysiloxane polymers.

[0147] Crosslinking may require a catalyst: - In the case of crosslinking organopolysiloxanes via hydrolysis condensation, the formulation may include metal catalysts, such as metal complexes based on platinum, tin, zinc, zirconium and cerium, particularly platinum-cyclovinylmethylsiloxane complexes, tin ethylhexanoate, zinc ethylhexanoate, zirconium ethylhexanoate, cerium ethylhexanoate and dibutyltin laurate.

[0148] - In the case of crosslinking organopolysiloxanes by hydrogenation acylation, it may be necessary to add a catalyst: this can be, for example, platinum or a suitable platinum-based catalyst, such as Karstedt catalyst or Ashbys catalyst.

[0149] Crosslinking agents, such as those carrying Si-H bonds, may be present.

[0150] The advantages of using the above-mentioned polymers with very high thermal stability, especially PAEK, under continuous use conditions at 260°C also lie in their very high mechanical properties (Young's modulus, tribology, low coefficient of friction, low surface energy, etc.) and their chemical resistance (excellent resistance to many solvents under acidic and alkaline conditions), their biocompatibility, their biostability, and their recyclability.

[0151] Other optional components of the coating Each of coating A and coating B advantageously includes at least one other optional component, typically selected from fillers, additives, colorants and mixtures thereof.

[0152] According to another embodiment, coating A or coating B includes at least one layer, the layer comprising: - Continuous phase; - Optionally one or more fillers; - Optionally one or more additives; - Optionally one or more colorants.

[0153] According to another embodiment, coating A or coating B includes at least one layer composed of the following: - Continuous phase; - Optionally one or more fillers; - Optionally one or more additives; - Optionally one or more colorants.

[0154] According to another embodiment, all layers of coating A or coating B include: - Continuous phase; - Optionally one or more fillers; - Optionally one or more additives; - Optionally one or more colorants.

[0155] According to another embodiment, all layers of coating A or coating B consist of the following: - Continuous phase; - Optionally one or more fillers; - Optionally one or more additives; - Optionally one or more colorants.

[0156] filler The possible presence of at least one filler allows for mechanical reinforcement and may also provide lubrication and hydrophobic properties when necessary, while improving the mechanical strength and thermal conductivity of the coating.

[0157] Fillers can help provide color to coatings.

[0158] Advantageously, if fillers are present, the fillers are selected from the group consisting of ceramic fillers (SiO2, etc.), mineral fillers and / or metal fillers (Al2O3, TiO2, etc.) and / or hydrophobic silica and / or diamond particles and mixtures thereof.

[0159] Preferably, the filler is selected from the group consisting of metal oxides, metal carbides, metal oxynitrides, metal nitrides, and mixtures thereof. Advantageously, the metal is a transition metal, for example, at least one element selected from B, Ni, Ti, Zr, or Hf.

[0160] Preferred fillers for use with organopolysiloxanes are: - Reinforcing filler: The filler content is at least 10-15% by weight relative to the total weight of the coating and can reach 60% by weight of silica or carbonate; - Alumina, hydrated alumina, aluminum hydroxide, silicon carbide (SiC); - D50 is less than 0.1 μm and specific surface area BET is greater than 30 m² 2 / g and preferably between 30m 2 / g and 500m 2Silicon dioxide (precipitated or pyrolyzed) between / g; - Or a mixture of quartz and silica, diatomaceous earth or ground quartz, titanium, mica, talc, kaolin, barium sulfate, quicklime, zinc oxide, expanded vermiculite, non-expanded vermiculite, calcium carbonate, etc.

[0161] Advantageously, the average diameter D50 of the packing is between 0.1 μm and 50 μm, and more advantageously between 5 μm and 15 μm.

[0162] Advantageously, the proportion of filler in a layer is between 0.5% and 60% of the total dry weight of the layer after baking, preferably between 5% and 50%.

[0163] additive Advantageously, if an additive is present, the additive is selected from the group consisting of defoamers, dispersants, wetting agents, thickeners, pH adjusters, and mixtures thereof.

[0164] Defoamers are typically selected from a group consisting of mineral oil, glycols, hydrocarbons, glycerides, ethylene oxide (also known as ethylene oxide), emulsified fatty acids, and mixtures thereof.

[0165] Surfactants are typically selected from the group consisting of glycol ethers, ethoxylated alcohols excluding alkylphenol ethoxylates (APE), Gemini surfactants, and mixtures thereof.

[0166] Dispersants are typically selected from the group consisting of anionic dispersants, such as fatty acid derivatives and mixtures thereof.

[0167] Thickeners are typically selected from the group consisting of acrylic or polyurethane copolymers, cellulose and its derivatives, pyrolytic silica and mixtures thereof.

[0168] pH adjusters are usually selected from Brönsted bases: a group consisting of ammonia, amines (triethylamine, triethanolamine, etc.), hydroxides (sodium hydroxide, potassium hydroxide, etc.), carbonates and their mixtures.

[0169] Preferred adhesion promoters for use with organopolysiloxanes are organosilanes or organopolysiloxanes having three hydrolyzable groups linked to silicon per molecule.

[0170] Advantageously, the proportion of the additive in each layer A or B is less than 20% by weight relative to the total weight of the coating.

[0171] Colorant Advantageously, the coating may include at least one colorant.

[0172] Advantageously, one or more colorants are selected from the group consisting of thermochromic pigments, thermally stable pigments, glitter and mixtures thereof.

[0173] Thermochromic Pigments Preferably, one or more thermochromic pigments are selected from Bi2O3, Fe2O3, V2O5, WO3, CeO2, In2O3, and Y. 1, 84 Ca 0,16 Ti 1,84 V 0,16 O 1,84 AgI, (Bi 1x A x (V) 1y M y The group consists of O4, where: - x equals 0 or x is between 0.001 and 0.999; - y equals 0 or y is between 0.001 and 0.999; - A and M are selected from groups composed of nitrogen, phosphorus, alkali metals, alkaline earth metals, transition metals, depleted metals, metalloids, or lanthanides; - A and M are different from each other.

[0174] Given that A and M are different from each other, when: - When A is an alkali metal, it can be selected from Li, Na, K, Rb, and Cs; - When M is an alkali metal, it can be selected from Li, Na, K, Rb, and Cs; - When A is an alkaline earth metal, it can be selected from Be, Mg, Ca, Sr, and Ba; - When M is an alkaline earth metal, it can be selected from Be, Mg, Ca, Sr, and Ba; - When A is a transition metal, it can be selected from Sc, Ti, Cr, Mn, Fe, Co, Ni, Cu, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Ta, W, and Ir; - When M is a transition metal, it can be selected from Sc, Ti, Cr, Mn, Fe, Co, Ni, Cu, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Ta, W, Ir; - When A is a metal-poor element, it can be selected from Al, Zn, Ga, In, and Sn; - When M is a metal-poor element, it can be selected from Al, Zn, Ga, In, and Sn; - When A is a metalloid, it can be selected from B, Si, Ge, and Sb; - When M is a metalloid, it can be selected from B, Si, Ge, and Sb; - When A is a lanthanide element, it can be selected from La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu; - When M is a lanthanide element, it can be selected from La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu.

[0175] Preferably, the different A and M are B and / or Mg.

[0176] Preferably, pigment (Bi) 1x A x (V) 1y M y O4 has the monoclinic alum crystallographic form at room temperature.

[0177] Preferably, x and y equal 0, that is, the pigment (Bi) 1x A x (V) 1y M y Bis(VO4) is bismuth vanadate. Advantageously, BiVO4 with a monoclinic jussite crystal structure is used at room temperature.

[0178] Bismuth vanadate is a yellow inorganic compound with the molecular formula BiVO4, widely used for its coloring properties and non-toxicity. Registered in the International Color Index Database as Qi Pigment Yellow 184, it is particularly marketed by Heubach (Vanadur®), BASF (Sicopal®), FERRO (Lysopac), and Bruchsaler Farbenfabrik (Brufasol®).

[0179] Heat-stable pigments Preferably, one or more thermally stable pigments are selected from the group consisting of: - Titanium redstone type yellow pigment; - Yellow pigments derived from bismuth, such as those selected from stabilized bismuth vanadate (Py 184 ); - Red pigments, such as those selected from perilla red (e.g., PR149, PR178 and PR224), iron oxide; - Bismuth oxyhalide type orange pigment (PO 85 ); - Bismuth vanadate orange pigment (PO) 86 ); - Zinc-tin-titanium orange pigment (PO) 82 ); - Cerium sulfide orange pigment (PO) 75 ;PO 78 ); - Antimony-titanium-chromium rutile orange-yellow pigment (PBr) 24 ); - Tin and zinc rutile orange-yellow pigments (Py 216 ); - Niobium tin oxide zinc sulfide orange-yellow pigment (Py 227 ); - A tin and niobium bioxide orange-yellow pigment; - Co3(PO4)2; - LiCoPO4; - CoAl2O4; - Cr2O3; - TiO2; - Black pigment PBk28 (black spinel copper chromite); - and its mixtures.

[0180] sequins The glitter usable within the scope of this invention can be independently selected from coated or uncoated mica glitter, coated or uncoated silica glitter, coated or uncoated aluminum glitter, and coated or uncoated iron oxide glitter. Mica or silica glitter coated with titanium dioxide may also be used. The glitter usable within the scope of this invention can be processed to give specific color effects.

[0181] Advantageously, one or more glitter particles are selected from the group consisting of mica particles, aluminum particles, mica particles coated with titanium dioxide, or mixtures thereof.

[0182] Holographic sequins Advantageously, one or more sequins are holographic sequins, that is, a mixture of magnetizable and non-magnetizable particles.

[0183] Magnetizable particles can advantageously be particles comprising at least one ferromagnetic metal. These magnetizable particles can be homogeneous, i.e., composed of the same material, or composite, i.e., having a core-shell structure in which the ferromagnetic metal is located in the core and / or shell of the particle. Examples of composite magnetizable particles include, in particular, mica flakes coated with iron oxide (Fe2O3) or stainless steel fibers coated with a sol-gel material as corrosion protection during the coating process; or plastic flakes coated with iron oxide (Fe2O3); or flakes with a core made of a ferromagnetic metal and a shell formed of plastic or sol-gel material.

[0184] According to one embodiment, a portion of the magnetizable particles is oriented to form a three-dimensional decoration.

[0185] Advantageously, the mixture of magnetizable and non-magnetizable particles accounts for between 1% and 5% of the layer weight, preferably between 2% and 3% by weight.

[0186] Advantageously, the percentage of non-magnetizable particles in the mixture of magnetizable and non-magnetizable particles is between 15% by weight and 40% by weight relative to the total weight of the mixture of magnetizable and non-magnetizable particles.

[0187] Advantageously, the magnetizable particles have a size D50 of less than or equal to 23 μm.

[0188] Advantageously, the non-magnetizable particles have a size D90 that is between 20% and 250% of the size D90 of the magnetizable particles.

[0189] Advantageously, magnetizable and / or non-magnetizable particles are colored on the surface.

[0190] Advantageously, the non-magnetizable particles are composed of mica, aluminum, or mica coated with titanium dioxide.

[0191] Advantageously, the magnetizable particles consist of iron, iron oxide, iron-coated aluminum, or iron-coated mica, with the iron present in ferrite form.

[0192] thing The present invention relates to a cooking article comprising a coated cooking element (1) obtained by the method according to the invention.

[0193] This cooking item is able to hold food on the coated surface of the coated cooking element (1).

[0194] Advantageously, the cooking items are selected from the following groups: pans with handles, long-handled frying pans, small pans with handles for cheese fondues or lacretes, double-handled lidded pans, frying pans, frying pans, crepe makers, grills, grill plates and grills, pressure cookers, stew pots, steaming pot containers, bread machine containers, waffle makers, grill plates and grills, molds and plates for pastry making, and preparation bowls.

[0195] The present invention also relates to an electrical cooking device comprising a coated cooking element (1) obtained by the method according to the present invention.

[0196] This electric cooking device is capable of holding food on the coated surface of the coated cooking element (1), the device including a heating source configured to heat the coated cooking element (1).

[0197] Advantageously, the electric cooking equipment is selected from a group consisting of electric crepe makers, lacrete appliances, cheese fondue appliances, electric grills, electric barbecue grills, electric cookers, bread makers, and pressure cooking appliances. Attached Figure Description

[0198] Other advantages and particularities of the invention will become apparent from the following description, which is given by way of non-limiting example and with reference to the examples and the accompanying drawings.

[0199] Figure 1 The method according to the invention for obtaining a coated cooking element (1) comprising coating A and coating B according to the invention is illustrated, wherein coating B overlaps coating A.

[0200] Figure 1 The diagram schematically illustrates the manufacture of a coated cooking element (1) according to the invention, based on a first configuration in which coating B overlaps coating A. A metal substrate (2) in the form of a flat disc is provided (step a) of the method according to the invention. The disc has a surface (2a) for coating. The surface (2a) has undergone or may undergo surface treatment (not shown). Coating A is applied in disc form to the central portion of the surface (2a), and then coating B is applied in ring form to at least the peripheral portion of the surface (2a) (step b) of the method according to the invention). A heat treatment step is performed (step c) of the method according to the invention). A substantially flat coated cooking element (1) is obtained.

[0201] Figure 2 The method for obtaining a coated cooking element (1) according to the invention, comprising coating A and coating B, is illustrated schematically, wherein coating A overlaps coating B.

[0202] Figure 2 The diagram schematically illustrates the manufacture of a coated cooking element (1) according to the invention, based on a second construction in which coating A overlaps with coating B. A metal substrate (2) in the form of a flat disc is provided (step a) of the method according to the invention. The disc has a surface (2a) for coating. The surface (2a) has undergone or may undergo surface treatment (not shown). Coating B is applied to the entire surface of the surface (2a), and then coating A is applied in disc form to the central portion of the surface (2a) (step b) of the method according to the invention. A heat treatment step is performed (step c) of the method according to the invention). A substantially flat coated cooking element (1) is obtained.

[0203] Figure 3 The method for obtaining a coated cooking element (1) according to the invention, comprising coating A and coating B, is illustrated schematically, wherein coating A overlaps coating B.

[0204] Figure 3The diagram schematically illustrates the manufacture of a coated cooking element (1) according to the invention, based on a first configuration in which coating A overlaps with coating B. A metal substrate (2) in the form of a flat disc is provided (step a) of the method according to the invention. The disc has a surface (2a) for coating. The surface (2a) has undergone or may undergo surface treatment (not shown). Coating B is applied in a ring form to at least the peripheral portion of the surface (2a) (step b) of the method according to the invention), and then coating A is applied in a disc form to the central portion of the surface (2a). A heat treatment step is performed (step c) of the method according to the invention). A substantially flat coated cooking element (1) is obtained.

[0205] Figure 4 Schematic illustration of passing through Figure 1 or Figure 3 The method used to obtain coated cooking elements (1).

[0206] Figures 5 to 9 The overlapping area (X) of the coated cooking element (1) according to different embodiments of the present invention described below is schematically shown.

[0207] Figure 10 The stress-deformation curve of the material is shown. Detailed Implementation

[0208] Example Example 1: This example is in Figure 5 As shown in the figure. In this example, in the overlap region (X), all layers of coating A (A1 and A′) overlap with all layers of coating B (B1, B′, and B′′). In the overlap region, layer B1 is in contact with layer A1.

[0209] The manufacturing of the coated cooking element (1) has been performed in the following steps in sequence: 1. Provide a substrate in the form of an aluminum disc with a thickness of 3.4 mm and a diameter of 340 mm (2); 2. Prepare the surface (2a) of the substrate (2) for coating by brushing and hydration; 3. The material coated on the peripheral portion of surface (2a) is a continuous phase of PES layer B′; 4. Dry at 100℃; 5. The material on which the continuous phase is coated on layer B′ is PES layer B′′; 6. Dry at 100℃; 7. Layer B1, which is an organopolysiloxane polymer, is coated onto layer B′′ by spraying. 8. A layer A1 of a sol-gel material is coated by spraying a continuous phase material onto the central portion of the surface (2a), such that layer A1 overlaps with layer B in the overlap region (X); 9. Dry at 70℃; 10. Layer A′, on which a continuous phase is coated, is a sol-gel material; 11. Heat treat the coated pan at 300°C for 45 min to obtain coated cooking elements (1).

[0210] Applying layer A1 onto layer B1 is done in a wet-to-wet manner (step 8).

[0211] Comparison Example 1: The method is the same as in Example 1, but also includes a drying step between the application layer B1 and the application layer A1 (steps 7 and 8).

[0212] Example 2: This example is in Figure 6 As shown in the figure. In this example, in the overlap region (X), all layers of coating B (B1, B′, and B′′) overlap with all layers of coating A (A1 and A′). In the overlap region, layer A1 is in contact with layer B1.

[0213] The manufacturing of the coated cooking element (1) has been performed in the following steps in sequence: 1. Provide a substrate in the form of an aluminum disc with a thickness of 3.4 mm and a diameter of 340 mm (2); 2. Prepare the surface (2a) of the substrate (2) for coating by brushing and hydration; 3. The material coated on the central portion of surface (2a) is a sol-gel material layer A′; 4. Dry at 70℃; 5. Layer A1, on which a continuous phase material is sprayed onto layer A′, is a sol-gel material; 6. A continuous phase material, PES, is coated by spraying onto the peripheral portion of surface (2a) such that layer B1 overlaps with layer A in the overlap region (X). 7. Dry at 100℃; 8. The material on which the continuous phase is coated on layer B1 is layer B′ of PES; 9. Dry at 100℃; 10. The material coated on layer B′ is an organopolysiloxane polymer layer B′′; 11. Heat treat the coated pan at 300°C for 45 min to obtain coated cooking elements (1).

[0214] Applying layer B1 onto layer A1 is done in a wet-to-wet manner (step 6).

[0215] Comparison Example 2: The method is the same as in Example 2, but also includes a drying step between the application layer A1 and the application layer B1 (steps 5 and 6).

[0216] Example 3: This example is in Figure 7 As shown in the figure. In this example, coating A comprises two layers (A1 and A2), and coating B comprises three layers (B1, B2, and B'). In the overlap region (X), layer A1 overlaps with and contacts layer B' and layer B1, and layer B2 overlaps with and contacts layer A1 and layer A2.

[0217] The manufacturing of the coated cooking element (1) has been performed in the following steps in sequence: 1. Provide a substrate in the form of an aluminum disc with a thickness of 3.4 mm and a diameter of 340 mm (2); 2. Prepare the surface (2a) of the substrate (2) for coating by brushing and hydration; 3. The material coated on the peripheral portion of surface (2a) is a continuous phase of PES layer B'; 4. Dry at 100℃; 5. The material on which the continuous phase is coated by spraying is layer B1 of PES; 6. A layer A1 of a sol-gel material is coated by spraying a continuous phase material onto the central portion of the surface (2a) such that layer A1 overlaps with layer B' and layer B1 in the overlapping region (X); 7. Dry at 70℃; 8. Layer A2, on which a continuous phase material is coated by spraying, is a sol-gel material; 9. Dry at 70℃; 10. In the overlapping region (X), a layer B2 of an organopolysiloxane polymer is sprayed onto layer A1 and layer B1, such that layer B2 overlaps with layer A in the overlapping region (X). 11. Heat treat the coated pan at 300°C for 45 min to obtain coated cooking elements (1).

[0218] Applying layer A1 onto layer B1 is done in a wet-to-wet manner, and then applying layer B2 onto layer A2 is done in a wet-to-dry manner.

[0219] Compare Example 3: The method is the same as in Example 3, but also includes a drying step at 100°C between the application layer B1 and the application layer A1 (steps 5 and 6).

[0220] Compare example 3bis: The method is the same as in Example 3, but does not include the drying step (step 9) between applying layer A2 and applying layer B2 (steps 8 and 10).

[0221] Example 4: This example is in Figure 8 As shown in the figure. In this example, coating A comprises two layers (A1 and A'), and coating B comprises three layers (B1, B2, and B'). In the overlap region (X), layer A1 overlaps with and contacts layer B' and layer B1, and layer B2 overlaps with and contacts layer A1.

[0222] The manufacturing of the coated cooking element (1) has been performed in the following steps in sequence: 1. Provide a substrate in the form of an aluminum disc with a thickness of 3.4 mm and a diameter of 340 mm (2); 2. Prepare the surface (2a) of the substrate (2) for coating by brushing and hydration; 3. The material coated on the peripheral portion of surface (2a) is a continuous phase of PES layer B'; 4. Perform tunnel drying to 100°C; 5. The material on which the continuous phase is coated by spraying is layer B1 of PES; 6. A layer A1 of a sol-gel material is coated by spraying a continuous phase material onto the central portion of the surface (2a) such that layer A1 overlaps with layer B' and layer B1 in the overlapping region (X); 7. Dry at 70℃; 8. In the overlapping region (X), layer B2 of an organopolysiloxane polymer is coated by spraying onto layer A1 and layer B1, such that layer B2 overlaps with layer A1 in the overlapping region (X); 9. The material coated on the central portion of surface (2a) is a sol-gel material layer A'; 10. Heat-treat the coated pan at 300°C for 45 min to obtain coated cooking elements (1).

[0223] Layer A1 is applied to layer B1 in a wet-on-wet manner. Layer B2 is applied to layer A1 in a wet-on-dry manner.

[0224] Compare Example 4: The method is the same as in Example 4, but does not include the drying step (step 7) between applying layer A1 and applying layer B2 (steps 6 and 8).

[0225] Example 5: This example is in Figure 9 As shown in the figure. In this example, coating A comprises two layers (A1 and A2), and coating B comprises three layers (B1, B', and B''). In the overlap region (X), layer A1 overlaps with and contacts layer B' and layer B1, and layer A2 overlaps with and contacts layer B1.

[0226] The manufacturing of the coated cooking element (1) has been performed in the following steps in sequence: 1. Provide a substrate in the form of an aluminum disc with a thickness of 3.4 mm and a diameter of 340 mm (2); 2. Prepare the surface (2a) of the substrate (2) for coating by brushing and hydration; 3. The material coated on the peripheral portion of surface (2a) is a continuous phase of PES layer B'; 4. Dry at 100℃; 5. The material on which the continuous phase is coated by spraying is layer B1 of PES; 6. A continuous phase material, a sol-gel material, is sprayed onto the central portion of surface (2a) such that layer A1 partially overlaps with layers B' and B1 in the overlap region (X); 7. In the overlapping region (X), the material coated on layer B1 and layer A1 is a sol-gel material, layer A2, such that layer A2 overlaps with layer B' and layer B1 in the overlapping region (X); 8. Dry at 70℃; 9. The material coated on layer B1 is an organopolysiloxane polymer layer B''; 10. Heat-treat the coated pan at 300°C for 45 min to obtain coated cooking elements (1).

[0227] Applying layer A1 to layer B1 and layer A2 to layer B1 is done in the form of wet layer to wet layer.

[0228] Compare Example 5: The method is the same as in Example 5, but also includes a drying step between the application layer B1 and the application layer A2 (steps 5 and 7).

[0229] result: The following table shows the results obtained through visual observation of the mechanical strength of the coating in the overlapping area. When large cracks, delamination, blistering, powder appearance, complete peeling and / or crack detailing problems are observed, the test coating is evaluated as an unqualified coating (abnormal), or in other cases as a qualified coating (normal).

[0230] [Table 2] [Table 3]

Claims

1. A method for manufacturing a coated cooking element (1), comprising the following steps in the following order: a) Provide a metal substrate (2) in the form of a substantially flat disk, the metal substrate (2) having a surface (2a) for coating. b) Apply coating A and coating B to the surface (2a); c) Perform heat treatment on the coated substrate (2) obtained after step b); in: - The coating B is different from the coating A; - The coating A covers only the central portion of the surface (2a) in the form of a disc, and the coating B covers at least the peripheral portion of the surface (2a) not covered by the coating A; - The coating A and the coating B overlap in the overlap region (X); - The coating A includes a layer A1, which includes a sol-gel material; - The coating B includes a layer B1, which comprises a material selected from aromatic thermoplastic polymers or heterocyclic thermoplastic polymers and organopolysiloxane polymers; - Layer A1 and layer B1 are in contact in the overlapping region (X); and - The layers A1 and B1 are applied as wet layers to wet layers, unless when the layer A1 is applied first and the layer B1 comprises an organopolysiloxane polymer, then step b) further includes the step of drying the layer A1 before applying the layer B1.

2. The method for manufacturing a coated cooking element (1) according to any one of the preceding claims, wherein, The coating A is a two- or three-layer coating.

3. A method for manufacturing a coated cooking element (1) according to any one of the preceding claims, wherein, The coating B is a two- or three-layer coating.

4. A method for manufacturing a coated cooking element (1) according to any one of the preceding claims, wherein, The coating A and / or the coating B do not include fluorocarbon resin.

5. A method for manufacturing a coated cooking element (1) according to any one of the preceding claims, wherein, The overlapping area (X) is a ring with a width greater than or equal to 0 mm and less than or equal to 10 mm.

6. A method for manufacturing a coated cooking element (1) according to any one of the preceding claims, wherein, The coating B includes layer B2, which comprises a material selected from aromatic thermoplastic polymers or heterocyclic thermoplastic polymers, organopolysiloxane polymers, and mixtures thereof.

7. The method for manufacturing a coated cooking element (1) according to claim 6, wherein, The materials of layer B1 and layer B2 may be the same or different.

8. A method for manufacturing a coated cooking element (1) according to any one of the preceding claims, wherein, The aromatic thermoplastic polymer of layer B1 and, if necessary, the aromatic thermoplastic polymer of layer B2 are selected from polyaryletherketone (PAEK), poly(phenylene ether) (PPO), polyarylether sulfone (PAES), polyphenylene ether sulfone (PPSU), polyphenylene sulfide (PPS), poly(arylene sulfide) (PAS), liquid crystal polymers, and mixtures thereof.

9. A method for manufacturing a coated cooking element (1) according to any one of the preceding claims, wherein, The organopolysiloxane polymer of layer B1 is selected from methyl silicone resin and / or phenyl silicone resin and / or methylphenyl silicone resin, methyl silicone polyester resin (copolymer), phenyl silicone polyester resin (copolymer), methylphenyl silicone polyester resin (copolymer), silyl alkyd resin (copolymer), modified silicone resin and mixtures thereof.

10. A method for manufacturing a coated cooking element (1) according to any one of the preceding claims, wherein, The coating A further includes a layer A2, which comprises a sol-gel material.

11. The method for manufacturing a coated cooking element (1) according to claim 10, wherein, The materials of layer A1 and layer A2 may be the same or different.

12. A method for manufacturing a coated cooking element (1) according to any one of the preceding claims, wherein, Heat treatment step c) is carried out at a temperature between 230°C and 300°C.

13. A cooking article or an electric cooking appliance comprising a coated cooking element (1) capable of being obtained by the method according to claims 1 to 12.

14. The cooking article of claim 13, wherein the cooking article is selected from the group consisting of a frying pan with handle, a long-handled frying pan, a small frying pan or casserole dish with handle for cheese fondue or lacrete, a double-handled lidded pan, a frying pan, a frying pan, a crepe maker, a grill, a grill plate and grill, a pressure cooker, a stew pot, a steamer container, a bread machine container, a waffle maker, a grill plate and grill, molds and plates for pastry making, and a preparation bowl.

15. The electric cooking apparatus according to claim 13, wherein the electric cooking apparatus is selected from the group consisting of an electric crepe maker, a lacrete appliance, a cheese fondue appliance, an electric grill, an electric grill plate, an electric steamer, a bread maker, and a pressure cooking appliance.

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