Non-fluorinated hybrid sol-gel / silicone resin coating

Abstract

The present invention relates to a coated cooking element (1) for a kitchen utensil or electrical cooking appliance, comprising a metal substrate (2) coated, on at least one face (2a), with at least the following layers in this order, starting from the metal substrate (2): (3a) a sol-gel base layer; (3c) a sol-gel layer obtained from a sol-gel mixture (SG) comprising a metal alkoxide precursor having an aliphatic chain that comprises at least one unsaturated compound and / or is substituted by a thiol group; and (3d) a finishing layer in contact with the layer (3c) and comprising an elastomer silicone obtained from at least one organopolysiloxane bearing reactive vinyl functional groups (-CH=CH2) and at least one other organopolysiloxane bearing reactive hydrosilane functional groups (-Si-H) or reactive thiol functional groups (-S-H).

Description

[0001] DESCRIPTION

[0002] Non-fluorinated hybrid sol-gel / silicone resin coating

[0003] The field of the invention is that of culinary articles coated on one of their faces by a coating and more specifically, silicone resin-based coatings of these articles.

[0004] In the field of cookware, fluoropolymer-based coatings, and in particular polytetrafluoroethylene (PTFE), are widely known for their non-stick and temperature-resistant properties. However, these coatings have low mechanical strength.

[0005] Application WO 2020 / 144051 concerns a fluoropolymer-based coating whose mechanical resistance to abrasion is improved by the integration of inorganic (SiC) and mineral (Al2O3) fillers in the primer and topcoat layers. The performance gain achieved with regard to mechanical resistance is satisfactory but still not optimal.

[0006] To improve resistance to mechanical impacts, coatings with a hard base layer coated with a sol-gel coating are also known, as described in particular in patents EP 2 334444 and EP 2 334445. However, such coatings do not allow for sufficiently precise temperature control.

[0007] Fluoropolymer-based coatings are primarily intended for pans and pots, but other applications can be considered in the field of mold making (molds, cake tins, waffle irons, etc.) or small domestic equipment (rice cookers, fryer vats, electric crepe makers) due to their deep-drawing capability.

[0008] An alternative to PTFE coatings is the use of so-called "ceramic" coatings, developed via a sol-gel process and the use of tetraethyl orthosilicate (EP 2 806776 B1). These coatings are characterized by their hardness and resistance to mechanical wear, but exhibit brittle behavior and lower anti-adhesion properties compared to fluoropolymer-based coatings.

[0009] Furthermore, these coatings are poorly suited to mold making and small household appliances due to their lack of deep-drawing properties. In the mold making sector (consumer or industrial), fluoropolymer-based coatings are not as widespread because the temperature resistance requirements are lower (max 220°C), allowing the use of other types of coatings, such as silicone.

[0010] Pure silicone resins are described as non-stick and resistant to temperatures above 220-230°C. However, they are considered to have poor adhesion to the substrate.

[0011] Conversely, silicone-polyester resins are widely used in mold making because they are non-stick while still adhering to the substrate and are compatible with stamping processes. However, they degrade at temperatures above 230°C. Indeed, the operating temperature range for cookware is between 50 and 250°C, and it is not surprising to reach temperatures of 300°C or even 350°C in the case of items with induction bases. Therefore, the use of silicone-polyester resins is not compatible with the operating temperatures required for cookware.

[0012] Application WO 2024 / 023472 describes a hybrid sol-gel coating architecture with a sol-gel base coat, one or more intermediate coats comprising one or more colorants, and a top coat comprising a silicone resin. If the coating's performance is satisfactory, its durability could be increased by improving the adhesion of the top coat to the sol-gel base coat.

[0013] Thus, there is a need for cooking articles that guarantee good mechanical resistance, good thermal resistance, simple and flexible implementation - for example in terms of the variety of reagents that can be used - for reasonable industrial costs.

[0014] The present invention also addresses the technical problem of alternative solutions to PTFE-type fluorinated resin-based coatings.

[0015] The present invention proposes an alternative to coatings based primarily on PTFE, aiming to achieve good resistance to mechanical wear, particularly on kitchen utensils and cookware, thereby improving the durability of their mechanical resistance, especially when heated, and / or their cleanability, in order to extend the product's lifespan. SUMMARY OF THE INVENTION

[0016] A first object of the invention relates to a coated cooking element (1) for a cooking article or electric cooking appliance, comprising a metallic substrate (2) coated on at least one face (2a) by at least the following layers and in this order from the metallic substrate (2):

[0017] (3a) a sol-gel base layer;

[0018] (3b) optionally one or more intermediate layer(s) which may be decorations;

[0019] (3c) a sol-gel layer obtained from a sol-gel mixture (SG) comprising a metal alkoxide-type precursor having an aliphatic chain comprising at least one unsaturation and / or substituted by a thiol group, and

[0020] (3d) a top layer in contact with layer (3c) and comprising an elastomeric silicone obtained from at least one organopolysiloxane bearing vinyl reactive functions (-CH=CH2) and at least one other organopolysiloxane bearing silyl hydride reactive functions (-Si-H) or thiol reactive functions (-SH), wherein, when the elastomeric silicone of layer (3d) is obtained from at least one organopolysiloxane bearing thiol reactive functions (-SH), the metal alkoxide precursor of layer (3c) has an aliphatic chain comprising at least one unsaturation and which may further be substituted by a thiol group (-SH).

[0021] A second object of the invention relates to a method for manufacturing a coated cooking element (1) according to the first object of the invention comprising the following successive steps:

[0022] i. supply of a metallic substrate (2) comprising at least one face (2a) intended to be coated,

[0023] ii. possibly, pretreatment of the face (2a),

[0024] iii. application of a base layer (3a) on face (2a),

[0025] iv. possibly, drying of the base coat (3a),

[0026] v. where applicable, application of layer(s) (3b),

[0027] vi. possibly, drying of the layer(s) (3b),

[0028] vii. application of the sol-gel layer (3c),

[0029] viii. optionally, drying of layer (3c) and / or firing of layers (3a), (3c), and where applicable (3b),

[0030] ix. application of the topcoat (3d),

[0031] x. cooking of the layers and obtaining the element (1). Another object of the invention relates to a cooking article (100) or electric cooking appliance (200) comprising a coated cooking element (1) according to the first object of the invention or capable of being obtained according to the process corresponding to the second object of the invention.

[0032] The present invention offers at least one of the following advantages:

[0033] - the coating according to the invention exhibits significant thermal stability during temperature increases; it is stable up to approximately 400°C;

[0034] - the coating according to the invention has enhanced mechanical resistance due to the presence of a sol-gel base layer compared to a coating comprising layers of silicone only;

[0035] - the coating according to the invention has improved durability due to the specific nature of the metal alkoxide type precursors of the sol-gel composition of layer (3c) and of the composition of layer (3d) compared to coatings comprising a base-sol-gel layer and a silicone coating described in the prior art;

[0036] - the manufacturing process of the coating of the invention requires lower cooking temperatures than for a coating comprising PTFE-type fluorinated resins, which improves the environmental impact of the coating of the invention and the energy efficiency of its manufacturing process.

[0037] DEFINITIONS

[0038] The term "layer," as used in the present invention, refers to a continuous or discontinuous layer. A continuous layer (also called a monolithic layer) is a single unit forming a flat surface that completely covers the area on which it is laid. A discontinuous layer (or non-monolithic layer) may comprise several parts and is therefore not a single unit.

[0039] The terms "base coat," "primer coat," "bonding coat," or "bonding primer" refer to all layers from the first coat applied directly to the substrate (it is preferable that this coat adheres well to the substrate and provides all its mechanical properties to the coating: hardness, scratch resistance) to the last coat before the first intermediate or decorative coat, or the topcoat if the coating does not include an intermediate coat. The term "topcoat" or "finish" refers to one or more continuous surface layers applied after the intermediate coat(s) if the coating includes them, or after the primer coat.Typically, the final topcoat, or even all topcoats, are transparent. This allows perfect visibility of any decorative layer while protecting all underlying layers from mechanical damage and giving the coating its non-stick properties. Ideally, the final topcoat is intended to come into contact with food.

[0040] The term "decoration" or "decorative layer" refers to one or more continuous or discontinuous layers comprising a pigment composition. The decoration may take the form of one or more patterns, or one or more colors. A decoration is clearly visible to the user with the naked eye and at a typical viewing distance.

[0041] For the purposes of this invention, "sol-gel composition" or "sol-gel" refers to a composition synthesized via the sol-gel process from a liquid-phase precursor solution, which is transformed into a solid through a series of chemical reactions (hydrolysis and condensation) at low temperature. The resulting composition may be either organo-mineral or entirely mineral.

[0042] For the purposes of this invention, "organo-mineral composition" means a composition whose network is essentially inorganic, but which contains organic groups, particularly due to the precursors used and the coating's curing temperature. Such a composition is generally obtained by a sol-gel process.

[0043] For the purposes of this invention, an "all-mineral composition" means a composition consisting of a completely inorganic material, free from any organic group. Such a composition is generally obtained by sol-gel process with a firing temperature of at least 400°C, or from tetraethoxysilane (TEOS) type precursors with a firing temperature that may be lower than 400°C.

[0044] For the purposes of this invention, "thermochromic pigment or pigment composition" means a pigment or pigment composition that changes color with temperature within a given temperature range, this change being reversible. This color change is visible to the user with the naked eye at normal viewing distances. "Thermo-stable pigment" means a pigment that does not change color when subjected to a temperature increase within a given temperature range, or that changes color when subjected to a temperature increase within a given temperature range so small that it is not visible to the user with the naked eye at normal viewing distances.

[0045] The term "d50" means, in the context of the present invention, the maximum dimension that 50% of the particles have by number.

[0046] The term "coating" refers to all the layers covering and adhering to the metallic substrate.

[0047] The term “silicone resin-based coating” means a coating which includes one or more silicone resins in one or more of its layers.

[0048] The coating obtained according to the invention is advantageously solid. By "solid" we mean the characteristic of a cohesive material insoluble in water, in common solvents, or in food components such as aqueous or fatty mixtures, even if the material may exhibit high hardness or high flexibility like an elastomer.

[0049] The term "cooking article" should be understood, for the purposes of this invention, as an object intended for cooking. To this end, it is designed to receive heat treatment. The cooking article thus comprises at least one "inner surface" or "cooking surface," the coating of which is intended to come into contact with food during cooking.

[0050] The expression "object intended to receive heat treatment" should be understood in the context of the present invention as an object which will be heated by an external heating system such as pans, pots, sauté pans, woks, barbecue grills and which is capable of transmitting the heat energy supplied by this external heating system to a material or food in contact with said object.

[0051] For the purposes of this invention, the term "electric cooking appliance" refers to a heating object with its own heating system, such as an electric crepe maker, electric raclette grill, electric fondue set, electric grill, electric griddle, electric cooker, bread maker, or electric pressure cooker. The electric cooking appliance thus comprises at least one "cooking surface," the coating of which is intended to come into contact with food during cooking.

[0052] In the present invention, % by weight are expressed in dry weight, i.e. without solvent.

[0053] FIGURES

[0054] [Fig.1]: Diagram of cooking element (1) according to the invention

[0055] [Fig.2]: Schematic of cooking element (1) according to the invention with a layer (3b)

[0056] [Fig. 3]: Diagram of a cooking article according to the invention

[0057] [Fig. 4]: Diagram of an electric cooking appliance according to the invention

[0058] DETAILED DESCRIPTION OF THE INVENTION

[0059] The invention relates to a coated cooking element (1) for a cooking article or electric cooking appliance, comprising a metallic substrate (2) coated on at least one face (2a) by at least the following layers and in this order from the metallic substrate (2):

[0060] (3a) a sol-gel base layer,

[0061] (3b) optionally one or more intermediate layer(s) which may be decorations, (3c) a sol-gel layer obtained from a sol-gel composition (SG) comprising a metal alkoxide type precursor having an aliphatic chain comprising at least one unsaturation and / or substituted by a thiol group (-SH),

[0062] (3d) a finishing layer in contact with layer (3c) comprising a silicone elastomer obtained from at least one organopolysiloxane bearing reactive vinyl functions (-CH=CH2) and at least one other organopolysiloxane bearing reactive silyl hydride functions (-Si-H) or reactive thiol functions (-SH),

[0063] in which, when the silicone elastomer of layer (3d) is obtained from at least one organopolysiloxane bearing reactive thiol functions (-SH), the metal alkoxide-type precursor of layer (3c) has an aliphatic chain comprising at least one unsaturation and which may further be substituted by a thiol group (-SH).

[0064] Advantageously, layers (3a), optionally (3b), (3c), and (3d) form a coating (3) that covers the metallic substrate (2). This coating (3) has non-stick properties and forms a non-stick surface. Advantageously, layer (3a) is in contact with the metallic substrate (2) via its face (2a).

[0065] At least one coated face (2a) of the metallic substrate is therefore a cooking face. In other words, the coating of the cooking element (1) according to the invention is intended to come into contact with food.

[0066] Advantageously, the finishing layer (3d) is intended to come into contact, by one of its faces (5), with food during cooking.

[0067] The coating of the cooking element (1) according to the invention does not comprise a fluorinated polymer, also called a fluoropolymer. In other words, said coating is free of fluorinated polymers.

[0068] Figure 1 represents a coated cooking element (1) according to the invention.

[0069] METALLIC SUBSTRATE

[0070] Advantageously, said metallic substrate (2) is a substrate of aluminum, stainless steel, cast iron or aluminum, iron, titanium or copper, or a multilayer metallic substrate.

[0071] Aluminium, as used in the present invention, means a metal consisting of 100% aluminium or an aluminium alloy.

[0072] The metallic substrate (2) can be a multilayer substrate, for example, bilayer or trilayer. Such multilayer substrates can be obtained, for example, by co-lamination, hot diffusion under load (solid-state bonding), or hot or cold impact bonding. Preferably, the metallic substrate (2) comprises alternating layers of metal and / or metal alloy. Preferably, the metallic substrate is a multilayer substrate whose face (2a) is made of aluminum alloy or stainless steel.

[0073] Advantageously, the thickness of the metallic substrate (2) is between 0.5 mm and 10 mm. Advantageously, the face (2a) of the metallic substrate (2) has previously undergone a surface treatment to improve the adhesion of the coating to said substrate.

[0074] According to one embodiment, the surface of the face (2a) of the metallic substrate (2) has undergone a surface treatment, said surface treatment being a chemical attack, a brushing, a hydration, a sandblasting, a shot blasting, a physicochemical treatment of the plasma or corona or laser type, a chemical activation or a combination of these different techniques.

[0075] As examples of usable metallic substrates in the present invention, advantageous examples include substrates made of anodized or unanodized aluminum, possibly polished, brushed, sandblasted, shot-blasted or micro-beaded; substrates made of anodized or unanodized aluminum alloy, possibly polished, brushed, sandblasted or micro-beaded; substrates made of steel, possibly polished, brushed, sandblasted, shot-blasted or micro-beaded; substrates made of stainless steel, possibly polished, brushed, sandblasted or micro-beaded; substrates made of cast steel, aluminum or iron; and substrates made of copper, possibly hammered or polished.

[0076] Advantageously, the substrate can be chosen from substrates comprising layers of ferritic stainless steel / aluminum / austenitic stainless steel, substrates comprising layers of stainless steel / aluminum / copper / aluminum / austenitic stainless steel, cast aluminum caps, aluminum or aluminum alloy caps lined with an outer stainless steel base, metallic co-laminated substrates, for example two-layer co-laminated substrates comprising a stainless steel layer (for example intended to form the inner face of the article) and an aluminum or aluminum alloy layer, anodized or not (for example intended to form the outer face of the article).

[0077] Advantageously, the average arithmetic roughness Ra of the surface of the face (2a) of the metallic substrate (2) is greater than or equal to 1 pm.

[0078] 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. 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 for non-contact measurement. The study of this surface topography allows the arithmetic mean roughness Ra to be defined.

[0079] GOL-FREEZE LAYERS (3a) and (3c)

[0080] Sol-gel coatings are obtained from sol-gel mixtures. They are produced via the sol-gel process from metal polyalkoxylate precursors and preferentially have a hybrid network, generally silica with grafted alkyl groups. A sol-gel (SG) coating is generally obtained from a sol-gel (SG) mixture comprising at least one metal oxide and at least one metal alkoxide precursor.

[0081] The formation of sol-gel mixtures as described below (layers (3a) and (3c)) consists of mixing an aqueous composition A comprising at least one metal oxide and a solution B comprising at least one metal alkoxide precursor. The mixing is advantageously carried out in a ratio of 40 to 75% by weight of the aqueous composition A relative to the weight of the sol-gel composition (A + B), so that the amount of metal oxide represents 5 to 50% by weight of the sol-gel composition (A + B) in the dry state.

[0082] The aqueous composition A may further comprise a solvent, in particular a solvent comprising at least one alcohol. An alcohol is preferably a C1-C6 alcohol. A C1-C6 alcohol is defined as a saturated hydrocarbon chain, linear or branched, comprising 1 to 6 carbon atoms and including a hydroxyl group (-OH) attached to a carbon atom. Examples include ethanol, n-propanol, and isopropanol.

[0083] The aqueous composition A may further comprise at least one silicone resin, in particular as defined below.

[0084] The aqueous composition A may further include a coloring agent, for example a pigment, in particular as defined below.

[0085] The aqueous composition A may further include a charge, in particular as defined below.

[0086] Aqueous composition A may also include fumed silica, the function of which is to regulate the viscosity of the sol-gel composition and / or the gloss of the dry coating. Aqueous composition A typically includes:

[0087] i) 5 to 50% by weight relative to the total weight of the aqueous composition A of at least one colloidal metal oxide,

[0088] ii) 0 to 20% by weight relative to the weight of composition A of a solvent comprising at least one alcohol,

[0089] iii) possibly 0.05 to 3% by weight relative to the total weight of said aqueous composition A of at least one silicone resin,

[0090] (iv) 5 to 30% pigment, and

[0091] v) 2 to 30% load.

[0092] Solution B may further comprise a Brønsted or Lewis acid. Advantageously, the metal alkoxide precursor of solution B is mixed with one or more Lewis acids, organic or mineral, representing 0.01 to 10% by weight of the total weight of solution B.

[0093] Specific examples of acids that can be used for mixing with the metal alkoxide precursor include acetic acid, citric acid, hydrochloric acid, formic acid, maleic acid, tartaric acid, or oxalic acid.

[0094] Solution B may further comprise a solvent, in particular a solvent comprising at least one alcohol.

[0095] Solution B may further include at least one silicone resin, in particular as defined below.

[0096] Solution B may further comprise a coloring agent, such as glitter, preferably metallic, in particular as defined below.

[0097] According to an advantageous embodiment of the process of the invention, solution B may comprise a mixture of one of the alkoxysilanes as defined below and a metallic alkoxide (for example, of aluminium, zirconia, titanium...).

[0098] According to a preferred embodiment, the sol-gel mixture is synthesized via the sol-gel process from a sol-gel mixture comprising or consisting of a metal alkoxide precursor as described below, and optionally:

[0099] a colloidal metal oxide precursor, a solvent, preferably alcoholic,

[0100] a Brønsted or Lewis acid, preferably an acid selected from acetic acid, citric acid, hydrochloric acid, formic acid, maleic acid, tartaric acid or oxalic acid,

[0101] additives selected from at least one silicone resin, at least one pigment, at least one filler, glitter, including metallic glitter, fumed silica, or a mixture thereof, or

[0102] a mixture of these.

[0103] Thus, the sol-gel mixture is preferably mineral or organomineral, and may include at least one silicone resin, at least one pigment, at least one filler, glitter (particularly metallic), fumed silica, or a mixture thereof. The SG composition may also include a solvent, particularly an alcoholic solvent, especially in trace amounts, and / or an acid, preferably one selected from acetic acid, citric acid, hydrochloric acid, formic acid, maleic acid, tartaric acid, or oxalic acid.

[0104] Sol-gel base layer (3a)

[0105] The sol-gel base layer (3a) is obtained from a sol-gel mixture comprising a metal alkoxide type precursor preferably chosen from the group consisting of: - precursors corresponding to the general formula Mj(ORj) n ,

[0106] - precursors conforming to the general formula Mii(ORii)( n -1)Rii',

[0107] - precursors corresponding to the general formula Miii(ORiii)(n-2)Riii'2, and

[0108] - their mixtures,

[0109] with:

[0110] Ri, Rü, or Rin designating an alkyl group,

[0111] Rin' designates a saturated or unsaturated aliphatic chain

[0112] RÜ' designating a saturated or unsaturated aliphatic chain, or a phenyl group, n being an integer corresponding to the maximum valence of the metals Mj, Mu or Min, Mi, Mü or Mjü designating a metal chosen from Si, Zr, Ti, Sn, Al, Ce, V, Nb, Hf, Mg or Ln.

[0113] Advantageously, alkyl groups contain from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms. Advantageously, saturated or unsaturated aliphatic chains comprise from 1 to 14 carbon atoms.

[0114] Advantageously, the metal alkoxide type precursor is an alkoxysilane.

[0115] Examples of usable alkoxysilanes include methyltrimethoxysilane (MTMS), tetraethoxysilane (TEOS), methyltriethoxysilane (MTES), dimethyldimethoxysilane, and mixtures thereof.

[0116] Preferably, alkoxysilanes MTES and TEOS are used, as they have the advantage of not containing methoxy groups. Indeed, the hydrolysis of methoxy groups can lead to the formation of methanol in the sol-gel formulation, which, given its toxic classification, necessitates additional precautions during application. Conversely, the hydrolysis of ethoxy groups generates only ethanol, which has a more favorable classification and therefore less stringent usage requirements for the sol-gel coating.

[0117] The layer (3a) may comprise at least one metal oxide, preferably a colloidal metal oxide selected from colloidal silica and / or colloidal alumina and / or colloidal zirconia and / or colloidal titanium.

[0118] Layer (3a) may include a silicone oil.

[0119] Advantageously, the thickness of the layer (3a) is between 5 pm and 100 pm, preferably between 8 pm and 70 pm, particularly preferably between 10 pm and 30 pm.

[0120] Sol-frost layer (3c)

[0121] The sol-gel layer (3c) is obtained from a sol-gel mixture comprising a metal alkoxide type precursor having an aliphatic chain comprising at least one unsaturation and / or substituted by a thiol group.

[0122] A metal alkoxide chosen from the group consisting of: is preferably used as a precursor.

[0123] - precursors conforming to the general formula Mi (ORi )( n -i)Ri,

[0124] - precursors conforming to the general formula M2(OR2)( n -2)R2 R? ”, - the precursors responding to the general formula M3(OR3)( n -3)R3'R3''R3''',and

[0125] - their mixtures,

[0126] n being an integer corresponding to the maximum valence of the metals Mi, M? or M3, M1, M? or M3 denoting a metal chosen from Si, Zr, Ti, Sn, Al, Ce, V, Nb, Hf, Mg or Ln; with:

[0127] - Ri, R? or R3 designating an alkyl group,

[0128] - R designating an aliphatic chain comprising at least one unsaturation and / or substituted by a thiol group,

[0129] - R? designating an aliphatic chain comprising at least one unsaturation and / or substituted by a thiol group; and

[0130] R? designating an alkyl group, or designating an identical or different aliphatic chain comprising at least one unsaturation and / or substituted by a thiol group; - R3' designating an aliphatic chain comprising at least one unsaturation and / or substituted by a thiol group, and R3 and R3 designating an identical or different alkyl group; or

[0131] R3' designating an aliphatic chain comprising at least one unsaturation and / or substituted by a thiol group, and, independently, R3 designating an identical or different aliphatic chain comprising at least one unsaturation and / or substituted by a thiol group, and R3 designating an alkyl group; or

[0132] R3', R3 and R3 independently designate an aliphatic chain, identical or different, comprising at least one unsaturation and / or substituted by a thiol group.

[0133] Depending on the embodiments,

[0134] - R denotes an aliphatic chain comprising at least one unsaturation;

[0135] - R? denotes an aliphatic chain comprising at least one unsaturation; and

[0136] R? denotes an alkyl group or denotes an identical or different aliphatic chain comprising at least one unsaturation;

[0137] - R3' denotes an aliphatic chain comprising at least one unsaturation, and R3 and R3 denote an identical or different alkyl group; or

[0138] R3' denotes an aliphatic chain comprising at least one unsaturation, and, independently, R3 denotes an identical or different aliphatic chain comprising at least one unsaturation and R3 denotes an alkyl group; or

[0139] R3', R3 and R3 independently designate an aliphatic chain, identical or different, comprising at least one unsaturation.

[0140] According to some embodiments, -R denotes an aliphatic chain substituted by a thiol group;

[0141] - R? denotes an aliphatic chain substituted by a thiol group; and

[0142] R? denotes an alkyl group or denotes an identical or different aliphatic chain substituted by a thiol group;

[0143] - R3' denotes an aliphatic chain substituted with a thiol group, and R3 and R3 denote an identical or different alkyl group; or

[0144] R3' denotes an aliphatic chain substituted with a thiol group, and, independently, R3 denotes an identical or different aliphatic chain substituted with a thiol group, and R3 denotes an alkyl group; or

[0145] R3', R3 and R3 independently designate an aliphatic chain, identical or different, substituted by a thiol group.

[0146] Advantageously, alkyl groups contain from 1 to 12 carbon atoms, preferably from 1 to 8 carbon atoms.

[0147] Advantageously, aliphatic chains containing at least one unsaturation comprise from 2 to 14 carbon atoms. Aliphatic chains may include at least one terminal vinyl group or at least one unsaturated group -CH=CH-. Advantageously, aliphatic chains containing at least one unsaturation are linear chains. Advantageously, aliphatic chains containing at least one unsaturation are linear, comprise from 2 to 14 carbon atoms, and have a terminal vinyl group. Thus, advantageously, aliphatic chains containing at least one unsaturation have the formula CH2=CH-(CH2). n - with n ranging from 0 to 12.

[0148] Advantageously, thiol-substituted aliphatic chains comprise from 1 to 14 carbon atoms. These aliphatic chains include at least one terminal -SH group. Advantageously, thiol-substituted aliphatic chains are linear chains. Advantageously, thiol-substituted aliphatic chains are linear, comprise from 1 to 14 carbon atoms, and have a terminal -SH group. Thus, advantageously, thiol-substituted aliphatic chains have the formula -(CH2) n -SH with n ranging from 1 to 14.

[0149] Advantageously, M is silicon with a valence of 4 (n=4). In this case, the metal alkoxide precursor is an alkoxysilane having an aliphatic chain comprising at least one unsaturation and / or substituted by a thiol group. The alkoxysilane can be chosen from the group consisting of:

[0150] a trialcoxysilane bearing an aliphatic chain comprising at least one unsaturation and / or substituted by a thiol group,

[0151] a dialcoxysilane bearing one or two aliphatic chains comprising at least one unsaturation and / or substituted by a thiol group,

[0152] a monoalkoxysilane bearing one, two, or three aliphatic chains comprising at least one unsaturation and / or substituted by a thiol group, and

[0153] their mixtures.

[0154] Advantageously, alkoxysilane is chosen from the group consisting of:

[0155] - a trialcoxysilane carrying an aliphatic chain comprising at least one unsaturation, - a dialcoxysilane carrying one or two aliphatic chains comprising at least one unsaturation,

[0156] - a monoalkoxysilane bearing one, two or three aliphatic chains comprising at least one unsaturation,

[0157] - and their mixtures.

[0158] Advantageously, the precursor is a trialcoxysilane corresponding to the general formula Si(ORi)3Ri, a dialcoxysilane corresponding to the general formula Si(OR2 R2 R? or a monoalkoxysilane corresponding to the general formula Si(OR3)R3 R3 R3 or mixtures thereof, the R groups being as described above.

[0159] Advantageously, the alkoxysiloxane precursor is:

[0160] a trialcoxysilane corresponding to the general formula Si(ORi)3RI, where Ri is a methyl or ethyl group and R'1 is a linear aliphatic chain comprising 2 to 14 carbon atoms and a terminal vinyl function

[0161] a dialcoxysilane corresponding to the general formula Si(OR2)2R2 R2 ”, R2 being a methyl or an ethyl, R2 being a linear aliphatic chain comprising from 2 to 14 carbon atoms and a terminal vinyl function, and R2 being a methyl, an ethyl or a linear aliphatic chain comprising from 2 to 14 carbon atoms and a terminal vinyl function;

[0162] a monoalkoxysilane corresponding to the general formula Si(OR3)R3 R3 R3:

[0163] o R3 being a methyl or an ethyl,

[0164] o R3 being a linear aliphatic chain comprising from 2 to 14 carbon atoms and a terminal vinyl function, o R3 and R3 being independently of each other a methyl, an ethyl, or a linear aliphatic chain comprising from 2 to 14 carbon atoms and a terminal vinyl function; or

[0165] their mixtures.

[0166] Advantageously, in this embodiment, the linear aliphatic chains comprising from 2 to 14 carbon atoms and a terminal vinyl function are identical to each other.

[0167] Depending on the embodiment, the alkoxysiloxane precursor is:

[0168] a trialcoxysilane corresponding to the general formula Si(ORi )3RI, Ri being a methyl or an ethyl and R'1 being a linear aliphatic chain comprising 2 to 4 carbon atoms and a terminal vinyl function;

[0169] a dialcoxysilane corresponding to the general formula Si(OR2 R2 R? ”, R2 being a methyl or an ethyl, R2 being a linear aliphatic chain comprising 2 to 4 carbon atoms and a terminal vinyl function, and R2 being a methyl, an ethyl or a linear aliphatic chain comprising 2 to 4 carbon atoms and a terminal vinyl function;

[0170] a monoalkoxysilane corresponding to the general formula Si(OR3)R3 R3 R3:

[0171] o R3 being a methyl or an ethyl,

[0172] o R3 being a linear aliphatic chain comprising 2 to 4 carbon atoms and a terminal vinyl function,

[0173] o R3 and R3 being independently of each other a methyl, an ethyl, or a linear aliphatic chain comprising 2 to 4 carbon atoms and a terminal vinyl function; or

[0174] their mixtures.

[0175] Alkoxysilane may be vinyltrimethoxysilane (VTMO), vinyltriethoxysilane (VTEO), trivinylmethoxysilane (TVMO), trivinylethoxysilane (TVEO) or mixtures thereof.

[0176] When the alkoxysilane precursor has one or two aliphatic chains, each containing at least one unsaturation, it can be the only alkoxysilane in the sol-gel composition. It can therefore be:

[0177] a trialcoxysilane carrying an aliphatic chain comprising at least one unsaturation,

[0178] a dialcoxysilane carrying one or two aliphatic chains comprising at least one unsaturation

[0179] a monoalkoxysilane carrying one or two aliphatic chains comprising at least one unsaturation.

[0180] For example, the sol-gel composition may include vinyltrimethoxysilane or vinyltriethoxysilane as the sole alkoxysilane.

[0181] Such alkoxysilanes can also be considered in mixtures.

[0182] According to embodiments, an alkoxysilane precursor bearing one or two aliphatic chains comprising at least one unsaturation or a mixture of such precursors may be used in mixture with a trialcoxysilane bearing one aliphatic chain comprising at least one unsaturation.

[0183] For example, vinyltrimethoxysilane can be used in a mixture with trivinylmethoxysilane, or vinyltriethoxysilane can be used in a mixture with trivinylmethoxysilane.

[0184] The sol-gel mixture for layer (3c) may further include a metal alkoxide-type precursor not carrying unsaturation.

[0185] The sol-gel mixture for layer (3c) may comprise one or more alkoxysilane precursors bearing at least one aliphatic chain comprising at least one unsaturation in mixture with at least one metal alkoxide precursor not bearing an unsaturation.

[0186] Advantageously, the metal alkoxide precursor without unsaturation is chosen from the group consisting of methyltrimethoxysilane (MTMS), tetraethoxysilane (TEOS), methyltriethoxysilane (MTES), dimethyldimethoxysilane, and mixtures thereof. Thus, advantageously, layer (3c) is obtained from a sol-gel mixture comprising:

[0187] vinyltrimethoxysilane (VTMO) or vinyltriethoxysilane (VTEO), and,

[0188] trivinylmethoxysilane (TVMO) or trivinylethoxysilane (TVEO), and

[0189] of methyltrimethoxysilane (MTMS) or methyltriethoxysilane (MTES).

[0190] Examples of alkoxysilane mixtures for the sol-gel mixture for layer (3c) include the following mixtures:

[0191] vinyltrimethoxysilane and methyltrimethoxysilane,

[0192] vinyltrimethoxysilane and methyltriethoxysilane

[0193] trivinylmethoxysilane et methyltrimethoxysilane

[0194] trivinylmethoxysilane et methyltriethoxysilane

[0195] vinyltrimethoxysilane, trivinylmethoxysilane et methyltrimethoxysilane vinyltrimethoxysilane, trivinylmethoxysilane et methyltriethoxysilane vinyltriethoxysilane et methyltrimethoxysilane,

[0196] vinyltriethoxysilane et methyltriethoxysilane

[0197] trivinylethoxysilane et methyltrimethoxysilane

[0198] trivinylethoxysilane et methyltriethoxysilane

[0199] vinyltrimethoxysilane, trivinylethoxysilane et methyltrimethoxysilane vinyltrimethoxysilane, trivinylethoxysilane et methyltriethoxysilane vinyltriethoxysilane, trivinylmethoxysilane et methyltrimethoxysilane vinyltriethoxysilane, trivinylmethoxysilane et methyltriethoxysilane vinyltriethoxysilane, trivinylethoxysilane et methyltrimethoxysilane vinyltriethoxysilane, trivinylethoxysilane et methyltriethoxysilane

[0200] The layer (3c) may include at least one metal oxide, preferably a colloidal metal oxide selected from colloidal silica and / or colloidal alumina and / or colloidal zirconia and / or colloidal titanium.

[0201] Layer (3c) may include a silicone oil.

[0202] Advantageously, the thickness of layer (3c) is between 1 µm and 50 µm, preferably between 1.5 µm and 40 µm, and particularly preferably between 2 µm and 20 µm. LAYER (3d)

[0203] The top layer (3d) comprises a silicone elastomer obtained from at least one organopolysiloxane bearing vinyl reactive functions (-CH=CH2) and at least one other organopolysiloxane bearing silyl hydride reactive functions (-Si-H) or thiol reactive functions (-SH).

[0204] When the silicone elastomer of layer (3d) is obtained from at least one organopolysiloxane bearing reactive thiol (-SH) functions, the metal alkoxide-type precursor of layer (3c) has an aliphatic chain comprising at least one unsaturation and which may further be substituted by a thiol (-SH) group.

[0205] Advantageously, the top layer (3D) also includes:

[0206] - one or more thermoplastic polymers, and / or

[0207] - one or more additive(s), and / or

[0208] - one or more coloring agents.

[0209] At least one organopolysiloxane bearing vinyl reactive functions (-CH=CH2) and at least one other organopolysiloxane bearing silyl hydride reactive functions (-Si-H) or thiol reactive functions (-SH) are precursors which react to obtain an elastomeric silicone.

[0210] The silicone elastomer of the (3d) layer forms a network that can be composed of a combination of 4 simple organosiloxane units designated M, D, T and Q depending on the degree of substitution by the oxygen of the silicon atom, as described in the following table, where R is an organic substituent described later. [Table 1]

[0211] Degree of substitution

[0212] Structure Symbol by oxygen

[0213] R3Si–O– 1 M

[0214] R

[0215] 1

[0216] -O-Si-O- 2 D

[0217] 1

[0218] R

[0219] R

[0220] 1

[0221] -O-Si-O- 3 T

[0222] 1

[0223] 0

[0224] 1

[0225] 1

[0226] 0

[0227] 1

[0228] -O-Si-O- 4 Q

[0229] 1

[0230] 0

[0231]

[0232] 1

[0233] The precursors of the elastomer are organopolysiloxanes. These macromolecules are formed of M, D, T, and / or Q units as described in the table, where R is independently an alkyl group, in particular methyl, or aryl group, in particular phenyl, different natures of R being able to be present on the same macromolecule.

[0234] Organopolysiloxanes can be either linear or sparsely branched (the majority being D groups). Linear or sparsely branched organopolysiloxanes are generally liquid, more or less viscous at room temperature, and are called silicone oils.

[0235] Organopolysiloxanes bearing reactive (3d) layer functions are precursors that react via crosslinking, which is a polyaddition. This crosslinking occurs through a reaction between the reactive vinyl (-CH=CH2) functions present on one of the organopolysiloxanes and the reactive silyl hydride (-Si-H) or reactive thiol (-SH) functions present on the other organopolysiloxane mixed with the first.

[0236] This crosslinking can be achieved by thermal activation, UV irradiation, or chemical activation. Preferably, this crosslinking occurs in the presence of a catalyst or a radical initiator. In an embodiment whereby the silicone elastomer of the (3d) layer is obtained from at least one organopolysiloxane bearing reactive vinyl groups (-CH=CH2) and at least one other organopolysiloxane bearing reactive silyl hydride groups (-Si-H), the reaction preferably takes place in the presence of a metallic catalyst, for example platinum or a suitable platinum-based catalyst such as the Karstedt catalyst or the Ashbys catalyst.

[0237] In one embodiment, the silicone elastomer of the (3d) layer is obtained from at least one organopolysiloxane bearing reactive vinyl groups (-CH=CH2) and at least one other organopolysiloxane bearing reactive thiol groups (-SH), the reaction preferably takes place in the presence of a radical initiator. In one embodiment, this may be a thermally activated radical initiator such as 2,2'-Azobis(2-methylpropionamidine) dihydrochloride (or V50). In another embodiment, it may be a radical initiator activated by UV irradiation such as Irgacure®651 (2,2-Dimethoxy-2-phenylacetophenone).

[0238] Advantageously, organopolysiloxanes carrying reactive functions of the (3d) layer are silicone oils.

[0239] Reactive functional groups are present on each organopolysiloxane, with at least one and potentially two, three, or more, as much as the molecular structure allows. Silicone oils containing at least one reactive functional group are called "reactive oils." These reactive functional groups can be located either at the ends of the macromolecular chain (termination) or distributed along the chain.

[0240] Advantageously, the thickness of the topcoat (3d) is between 0.1 pm and 10 pm, preferably between 0.5 pm and 5 pm, particularly preferably between 1 pm and 2 pm.

[0241] LAYER(S) (3b)

[0242] In some embodiments, the coated substrate comprises one or more intermediate layers (3b), which may be decorative elements. In one embodiment, the layer(s) (3b) is / are continuous and covers the entire layer (3a) (see Figure 2).

[0243] According to another embodiment, the layer(s) (3b) do not cover the entire layer (3a) and form(s) at least one decoration.

[0244] Advantageously, the thickness of the layer(s) (3b) is between 1 pm and 100 pm, preferably between 2 pm and 30 pm, particularly preferably between 3 pm and 10 pm.

[0245] COATING

[0246] The different layers of the coating according to the invention may include other components such as thermoplastic polymers, fillers, additives, coloring agents and / or silicone resins.

[0247] THERMOPLASTIC POLYMERS

[0248] Advantageously, the thermoplastic polymer(s) is / are chosen from the group consisting of aromatic thermoplastic polymer(s) such as polyaryletherketone(s) (PAEK), poly(arylethersulfones) (PAES), poly(arylene sulfides) (PAS) or poly(phenylene oxide) (PPO), liquid crystal polymers, heterocyclic thermoplastic polymers and their mixtures.

[0249] Advantageously, the (3d) layer comprises one or more thermoplastic polymer(s), preferably in a weight proportion of said layer less than 15%, preferably 10%.

[0250] Heterocyclic thermoplastic polymers

[0251] As examples of suitable heterocyclic thermoplastic polymers according to the invention, polyetherimides (PEI), polyimides (PI), polyamideimides (PAI) and polybenzymidazole (PBI), or mixtures thereof, are cited.

[0252] Advantageously, the polyaryletherketone(s) (PAEK) is / are chosen from the group consisting of: polyetherketones (PEK), polyetheretherketone (PEEK), polyetherketoneketones (PEKK), polyetheretherketoneketones (PEEKK) and polyetherketoneetherketoneketones (PEKEKK), particularly preferably is / are PEEK.

[0253] CHARGES

[0254] The fillers described in the invention provide mechanical reinforcement and can also impart hydrophobic properties, while improving the mechanical strength and thermal conductivity of the coating. The fillers do not solely serve to add color to the coating, but can contribute to this function.

[0255] Advantageously, the filler(s) is / are chosen from the group consisting of ceramic fillers (SiO2, etc.) and / or mineral and / or metallic fillers (Al2O3, TiO2, etc.) and / or silica and / or diamond particles.

[0256] Preferably, the filler(s) is / are chosen from the group consisting of metal oxides, metal carbides, metal oxynitrides, metal nitrides, and mixtures thereof. Advantageously, said metal is boron or a transition metal, such as at least one of the elements chosen from Ni, Ti, Zr, or Hf.

[0257] Preferably, the charge(s) is / are chosen from the group consisting of:

[0258] - fillers for reinforcement: hard organic or inorganic fillers; the hard inorganic fillers are preferably particles of silicon carbide or alumina or zirconia or graphite, or ceramics, or carbonate, or hydrated alumina, aluminum trihydroxide or one or more metal oxide(s), graphite, graphene;

[0259] - other fillers for reinforcement chosen from among the metallic oxides: silica, micas, lamellar fillers, clays such as montmorillonite, sepiolite, gypsite, kaolinite and laponite, zinc dioxide, quartz, and zirconium phosphate, alumina, zirconia, zinc oxide, copper oxide, iron oxide;

[0260] - fillers selected from reinforcing fibers: glass or carbon or aramid fiber; - conductive fillers comprising a boron carbide and / or a boron nitride and / or a transition metal carbide and / or a transition metal nitride: characterized in that the transition metal is at least one of the elements selected from Ni, Ti, Zr or Hf; - lamellar fillers that can confer lubricating properties, such as clays, graphene, graphite or tungsten sulfide.

[0261] Preferably, the filler(s) is / are chosen from the group consisting of alumina, silicon carbide, tungsten carbide, boron nitride, quartz, and mixtures thereof.

[0262] Advantageously, the fillers present in the sol-gel layer (3a) or the optional intermediate layer(s) (3b) and the sol-gel layer (3c) are hard inorganic fillers, preferably oxides, carbides, metal nitrides, preferably alumina, silicon carbides or fumed silica.

[0263] Certain hard inorganic fillers, such as silicon carbide, in addition to their mechanical reinforcement properties, also offer the advantage of being conductive, thus providing excellent thermal conductivity. Adding this type of filler improves cooking performance by ensuring better heat distribution from the metallic substrate to the food in contact with the coating.

[0264] Advantageously, the average diameter d50 of the loads is between 0.1 and 50 pm, advantageously still between 5 and 15 pm.

[0265] Advantageously, the proportion of fillers in a layer is between 0.5 and 30% by dry weight relative to the total weight of said layer after baking, preferably between 5 and 20%.

[0266] Advantageously, the proportion of loads in layer (3a) is greater than 20% by weight, preferably greater than 30% by weight, relative to the total weight of said layer.

[0267] Advantageously, the proportion of charges in layers (3a) and (3c) can be identical or different.

[0268] Advantageously, the nature of the fillers in layers (3a) and (3c) can be identical or different. ADDITIVES

[0269] Advantageously, said additives are chosen from the group consisting of antifoaming agents, dispersing agents, wetting agents, thickeners, pH adjusters, reactive silicone oils.

[0270] The said antifoaming agent(s) (is) preferably chosen from the group consisting of mineral oils, diols, hydrocarbons, glycerides, oxyrane, emulsified fatty acids.

[0271] The surfactant(s) is / are preferably chosen from the group consisting of glycol ether, ethoxylated alcohol excluding alkyl phenol ethoxylates (APEs), gemini surfactants.

[0272] The dispersing agent(s) is / are preferentially chosen from the group consisting of anionic dispersants such as fatty acid derivatives.

[0273] The said thickeners are preferably chosen from the group consisting of acrylic-based or polyurethane-based copolymer, cellulose, fumed silica.

[0274] These pH adjusters are preferentially chosen from the group consisting of Brønsted bases: ammonia, amines (triethylamine, triethanolamine...), hydroxides (sodium hydroxide, potassium hydroxide...), carbonates.

[0275] Advantageously, the proportion of additives in layer (3a) is less than 1% by weight relative to the total weight of said layer.

[0276] Advantageously, the proportion of additives in the (3d) layer is less than 20% by weight relative to the total weight of said layer.

[0277] COLORING AGENTS

[0278] Advantageously, the coloring agent(s) is / are chosen from the group consisting of thermochromic pigments, heat-stable pigments, glitter, preferably holographic glitter, and mixtures thereof. TJ

[0279] Advantageously, the proportion of coloring agents in the layers (3a), optional (3b), (3c) and (3d) is between 0.5 and 50% by dry weight relative to the total weight of said layer after baking.

[0280] Advantageously, the proportion of coloring agents in the (3a), optional (3b) and (3c) layers ranges from 10 to 40% by weight relative to the total weight of said layer.

[0281] Advantageously, the proportion of coloring agents in the (3d) layer, when present, is less than 10% by weight relative to the total weight of said layer.

[0282] Advantageously, the proportion of coloring agents in layers (3a), optional (3b), (3c) and (3d) can be the same or different.

[0283] Advantageously, the nature of the coloring agents in layers (3a), optional (3b), (3c) and (3d) can be identical or different.

[0284] Advantageously, the (3D) layer is transparent. In this case, if it contains coloring agents, these coloring agents are glitter.

[0285] Thermochromic pigments

[0286] Preferably, the thermochromic pigment(s) is / are chosen from the group consisting of Bi2O3, Fe2O3, V2O5, WO3, CeO2, In2O3, Y 1,84 That 0,16 Ti 1,84 V 0,16 O 1,84 , AgI, (Bi 1-x HAS x (V) 1-y M y )O4with

[0287] x is equal to 0 or x is between 0.001 and 0.999,

[0288] y is equal to 0 or y is between 0.001 and 0.999,

[0289] A and M are chosen from the group consisting of nitrogen, phosphorus, an alkali metal, an alkaline earth metal, a transition metal, a post-oxidation metal, a metalloid, or a lanthanide.

[0290] A and M are different from each other.

[0291] Preferably, A and M, different from each other, are B and / or Mg.

[0292] Preferably, x and y are equal to 0, that is, the pigment (Bi 1-x HAS x (V) 1-y M y )O4 is Bismuth Vanadate (BiVO4). Advantageously, a BiVO4 with a monoclinic scheelite crystallographic structure is used at room temperature. Thermostable pigments

[0293] Preferably, the heat-stable pigment(s) is / are chosen from the group consisting of:

[0294] - Yellow pigment of the titanium rutile type,

[0295] - Yellow pigment derived from bismuth, for example selected from stabilized bismuth vanadates (Py 184 )

[0296] - Red pigment, for example selected from perylene red (e.g. PR149, PR178 and PR224), iron oxide,

[0297] - Orange pigment of the bismuth oxyhalide type (PO 85 ),

[0298] - Bismuth vanadate orange pigment (PO 86 )

[0299] - Zinc tin titanium orange pigment (PO 82 )

[0300] - Orange pigment of cerium sulfide (PO₄) 75 PO 78 )

[0301] - Yellow-orange pigment of the rutile type of antimony titanium chromium (PBr4)

[0302] - Yellow-orange pigment of the tin and zinc rutile type (Py?iô)

[0303] - Yellow-orange pigment of niobium oxide tin zinc sulfide (Py???)

[0304] - Yellow-orange pigment of double oxides of tin and niobium

[0305] - Co3(PO4)2

[0306] - LiCoPO4

[0307] - CoAl2O4

[0308] - Cr2O3

[0309] - TiO2

[0310] - Black pigment PBk28 (Copper chromite black spinel)

[0311] - and their mixtures.

[0312] Glitter

[0313] The glitter particles usable within the scope of the present invention can be independently selected from mica glitter, coated or uncoated, silica glitter, coated or uncoated, aluminum glitter, coated or uncoated, iron oxide glitter, coated or uncoated, or mica or silica glitter coated with titanium dioxide. The glitter particles usable within the scope of the present invention can be treated to give a particular color effect. Advantageously, the glitter particle(s) is / are particles selected from the group consisting of mica particles, aluminum particles, mica particles coated with titanium dioxide, or mixtures thereof. Holographic glitter particles

[0314] Advantageously, the glitter(s) is / are holographic glitter, that is to say a mixture of magnetizable and non-magnetic particles.

[0315] Magnetizable particles can advantageously be particles comprising at least one ferromagnetic metal. These magnetizable particles can be homogeneous, meaning they are made of the same material, or composite, meaning they have a core-shell structure in which the ferromagnetic metal is located in the core and / or the shell of the 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 corrosion protection during the coating application process; plastic flakes coated with iron oxide (Fe2O3); or flakes with a ferromagnetic metal core and a plastic or sol-gel material shell.

[0316] According to one embodiment, a portion of said magnetizable particles is oriented so as to form a three-dimensional decoration.

[0317] Advantageously, magnetizable and / or non-magnetizable particles are colored on the surface.

[0318] Advantageously, non-magnetizable particles are made of mica, aluminum, or mica coated with titanium dioxide.

[0319] Advantageously, magnetizable particles consist of iron, iron oxide, aluminum coated with iron, or mica coated with iron, the iron being in ferritic form.

[0320] SILICONE RESINS

[0321] In the description, the term "silicone resin" is used interchangeably to refer to silicone before or after crosslinking. In the description, "silicone" refers to an organopolysiloxane material. Crosslinking is the process that transforms silicone into an insoluble material, for example, through polyaddition, polycondensation, or dehydrogenation. Crosslinking is carried out using precursors, which are generally silicone oils or resins, that crosslink to form a three-dimensional network, creating a material referred to as silicone resin in the description.

[0322] This crosslinking can be achieved by thermal activation, or chemical activation using a catalyst, such as platinum.

[0323] Advantageously, the silicone resin(s), obtained after crosslinking of their precursors, i.e. crosslinked, is / are chosen from the group comprising methyl silicones and / or phenyl silicones and / or methyl-phenyl-silicones, methyl silicone-polyester resins (copolymers), phenyl silicone-polyester resins (copolymers), methyl-phenyl silicone-polyester resins (copolymers), silicone-alkyd resins (copolymers), modified silicone resins and their mixtures.

[0324] PROCESS

[0325] The invention also relates to a method for manufacturing a coated cooking element (1) according to the invention comprising the following successive steps:

[0326] i. supply of a metallic substrate (2) comprising at least one face (2a) intended to be coated,

[0327] ii. possibly, pretreatment of the face (2a),

[0328] iii. application of a base layer (3a) on face (2a),

[0329] iv. possibly, drying of the base coat (3a),

[0330] v. where applicable, application of layer(s) (3b),

[0331] vi. possibly, drying of the layer(s) (3b),

[0332] vii. application of the sol-gel layer (3c),

[0333] viii. optionally, drying of layer (3c) and / or baking of layers (3a), (3c) and where applicable (3b),

[0334] ix. application of the (3d) layer,

[0335] x. cooking of the layers and obtaining the element (1).

[0336] Step (iii) and step (vii) are implemented in particular as described above in relation to the sol-gel composition. According to one embodiment, at least one intermediate layer (3b) is applied on the base layer (3a) and a sol-gel layer (3c) is applied on the at least one intermediate layer (3b).

[0337] Advantageously, the steps of the process according to the invention allow the metallic substrate (2) to be coated with a coating (3) formed by at least three layers (3a), (3c), and (3d). Generally, these layers are wet during their application. For the purposes of this invention, a wet layer means a layer comprising all or part of its solvents.

[0338] Advantageously, the manufacturing process for a coated cooking element (1) according to the invention comprises one or more drying steps between 80 and 150°C after the application of each layer in order to remove all or part of the solvents from the wet layer. Drying can be carried out either naturally or by physical treatment (for example, by thermal drying (convection or infrared), by airflow drying, or by vacuum treatment).

[0339] The application of the coating according to the invention by the process according to the invention can be carried out on the shaped substrate or on a locally flat area of ​​the shaped substrate. Advantageously, the process for manufacturing a coated cooking element (1) according to the invention includes a shaping step of said substrate (2) before step iii. This shaping is also called stamping.

[0340] The process according to the invention comprises a step x. of baking the element obtained at the end of step ix. of the process. By baking the coated substrate, we mean, for the purposes of the present invention, a heat treatment which makes it possible to densify the coating layer(s) applied to the substrate and advantageously to crosslink the organopolysiloxane precursors of the layer (3d).

[0341] Without being bound by any particular theory, the cooking step x. would also allow reactive functions of layer (3c) and reactive functions of layer (3d) to react. For example, the following could react:

[0342] a portion of the silyl hydride functions provided by the at least one organopolysiloxane used for layer (3d) and the unsaturations introduced by the metal alkoxide precursor having an aliphatic chain comprising at least one unsaturation of the sol-gel layer (3c), or a portion of the thiol functions provided by the at least one organopolysiloxane used for layer (3d) and the unsaturations introduced by the metal alkoxide precursor having an aliphatic chain comprising at least one unsaturation of the sol-gel layer (3c), or

[0343] a part of the vinyl functions provided by the at least one organopolysiloxane used for the layer (3d) and the thiol functions introduced by the metal alkoxide type precursor having an aliphatic chain substituted by a thiol group of the sol-gel layer (3c).

[0344] The baking stage thus allows for a robust anchoring of the finishing layer (3d) on the sol-gel layer (3c), leading to a more durable non-stick coating.

[0345] In some embodiments, step viii includes a firing step following, where appropriate, a drying step as described above. The firing step may also be carried out without a prior drying step.

[0346] According to some embodiments, the process includes a single final co-baking step of the layers during step x. This single baking step is carried out simultaneously for all the applied layers.

[0347] In this case, the cooking during step x. is carried out at a temperature ranging from 150 °C to 350 °C, for a duration of 1 min to 45 min.

[0348] When a baking step of layers (3a), (3c), and where applicable (3b), is carried out during step viii, the baking step x is performed at a temperature ranging from 150°C to 300°C for a duration of 1 to 45 minutes. This process is advantageous compared to one comprising only a final baking step because it allows the temperature of the baking step x to be lowered.

[0349] According to an advantageous embodiment of the invention, the topcoat (3d) is applied to the coated substrate at a deposition rate of less than or equal to 5 g / m². 2 , preferably between 0.1 and 2.5 g / m 2 , even more preferentially between 0.2 and 2 g / m 2 .

[0350] Advantageously, the process according to the invention further includes a crosslinking step ix' of the topcoat (3d) subsequent to or simultaneous with step ix and preceding the baking step x. According to one embodiment, the crosslinking ix' of the composition of the layer (3d) can be activated, for example, by heat treatment, at a temperature between 50 and 400°C, preferably between 50 and 300°C, taking into account, of course, the maximum resistance of the substrate to heat.

[0351] Advantageously, the crosslinking of the (3d) layer composition is carried out at a temperature of 300°C for a duration of 10 min.

[0352] Advantageously, the higher the crosslinking temperature, the shorter the crosslinking time.

[0353] According to one embodiment, the crosslinking step ix' does not require heat treatment, in particular because the support is hot at the time of step ix.

[0354] Steps iii., vii. and ix. of application can be carried out by electrostatic powdering, by solvent-based or aqueous spray spraying, by screen printing, by roller or by digital printing.

[0355] Preferably, in particular step ix. is carried out by electrostatic powder coating, by spraying in solvent or aqueous phase.

[0356] Typically, the substrate has the final shape of the cooking article with a concave inner face 2a intended to be positioned on the side of the food likely to be introduced into said article, and a convex outer face intended to be positioned on the side of a heat source.

[0357] FAVORITE ARCHITECTURES

[0358] According to one embodiment, the invention relates to a coated cooking element (1) for a cooking article or electric cooking appliance, comprising a metallic substrate (2) coated on at least one face (2a) by, or exclusively by, the following three layers superimposed in this order from the metallic substrate (2):

[0359] (3a) a sol-frost layer,

[0360] (3c) a sol-gel layer obtained from a sol-gel mixture (SG) comprising a metal alkoxide precursor having an aliphatic chain comprising at least one unsaturation, (3d) a topcoat comprising a silicone elastomer obtained from at least one organopolysiloxane bearing vinyl reactive functions (-CH=CH2) and at least one other organopolysiloxane bearing silyl hydride reactive functions (-Si-H).

[0361] According to another embodiment, the invention relates to a coated cooking element (1) for a cooking article or electric cooking appliance, comprising a metallic substrate (2) coated on at least one face (2a) by, or exclusively by, the following three layers superimposed in this order from the metallic substrate (2):

[0362] (3a) a sol-frost layer,

[0363] (3c) a sol-gel layer obtained from a sol-gel mixture (SG) comprising a metal alkoxide-type precursor having an aliphatic chain comprising at least one unsaturation,

[0364] (3d) a topcoat comprising a silicone elastomer obtained from at least one organopolysiloxane bearing vinyl reactive functions (-CH=CH2) and at least one other organopolysiloxane bearing thiol reactive functions (-SH).

[0365] According to another embodiment, the invention relates to a coated cooking element (1) for a cooking article or electric cooking appliance, comprising a metallic substrate (2) coated on at least one face (2a) by, or exclusively by, the following three layers superimposed in this order from the metallic substrate (2):

[0366] (3a) a sol-frost layer,

[0367] (3c) a sol-gel layer obtained from a sol-gel mixture (SG) comprising a metal alkoxide type precursor having an aliphatic chain substituted by a thiol group (-SH),

[0368] (3d) a topcoat comprising a silicone elastomer obtained from at least one organopolysiloxane bearing vinyl reactive functions (-CH=CH2) and at least one other organopolysiloxane bearing silyl hydride reactive functions (-Si-H).

[0369] According to another embodiment, the invention relates to a coated cooking element (1) for a cooking article or electric cooking appliance, comprising a metallic substrate (2) coated on at least one face (2a) by, or exclusively by, the following three layers superimposed in this order from the metallic substrate (2):

[0370] (3a) a sol-gel layer, (3c) a sol-gel layer obtained from a sol-gel mixture (SG) comprising a metal alkoxide-type precursor having an aliphatic chain comprising at least one unsaturation and substituted by a thiol group (-SH),

[0371] (3d) a topcoat comprising a silicone elastomer obtained from at least one organopolysiloxane bearing vinyl reactive functions (-CH=CH2) and at least one other organopolysiloxane bearing silyl hydride reactive functions (-Si-H).

[0372] According to another embodiment, the invention relates to a coated cooking element (1) for a cooking article or electric cooking appliance, comprising a metallic substrate (2) coated on at least one face (2a) by, or exclusively by, the following three layers superimposed in this order from the metallic substrate (2):

[0373] (3a) a sol-frost layer,

[0374] (3c) a sol-gel layer obtained from a sol-gel mixture (SG) comprising a metal alkoxide type precursor having an aliphatic chain comprising at least one unsaturation and substituted by a thiol group (-SH),

[0375] (3d) a topcoat comprising a silicone elastomer obtained from at least one organopolysiloxane bearing vinyl reactive functions (-CH=CH2) and at least one other organopolysiloxane bearing thiol reactive functions (-SH).

[0376] According to a particular embodiment, the coating further comprises two intermediate layers (3b), of which at least one is a decorative layer.

[0377] Advantageously:

[0378] • the thickness of layer (3a) is between 5 pm and 100 pm, preferably between 10 pm and 30 pm,

[0379] • the thickness of layer(s) (3b), when present, is between 1 pm and 100 pm, preferably between 3 pm and 10 pm,

[0380] • the thickness of layer (3c) is between 1 pm and 50 pm, preferably between 2 pm and 20 pm, and

[0381] • The thickness of the topcoat (3d) is between 0.1 µm and 10 µm, preferably between 1 µm and 2 µm. ARTICLE

[0382] The invention also relates to a cooking article (100) comprising a coated cooking element (1).

[0383] According to an embodiment illustrated in Figure 3, the cooking article (100) comprises a heating surface (6) intended to be in contact with an external heat source, the heating surface (6) being opposite the cooking surface (2a) intended to be coated with the coating of the invention. The cooking surface (5) is typically the face of the coating according to the invention intended to come into contact with the food during cooking.

[0384] Advantageously, the culinary article (100) according to the invention is chosen from the group consisting of saucepan, frying pan, fondue or raclette pan, stockpot, wok, sauté pan, crepe pan, grill, plancha, pot, casserole dish, cooker or bread machine bowl, culinary mold.

[0385] The invention also relates to an electric cooking appliance (200) as illustrated in Figure 4 comprising a coated cooking element (1) according to the invention and a heating source (210) configured to heat said coated cooking element (1).

[0386] Advantageously, the electric cooking appliance (200) is chosen from the group consisting of electric crepe maker, electric raclette appliance, electric fondue appliance, electric grill, electric griddle, electric cooker, bread machine, electric pressure cooker, waffle makers, rice cookers and jam makers.

[0387] The culinary article according to the present invention may in particular be a culinary article in which one of the two opposite faces of the substrate is an inner face, possibly concave, intended to be disposed on the side of food likely to be introduced into or onto said article, and in which the other face of the substrate is an outer face, possibly convex, intended to be disposed towards a heat source.

[0388] By way of non-limiting examples of cookware conforming to the present invention, mention may be made in particular of cookware such as saucepans and frying pans, woks and sauté pans, stockpots and casseroles, crepe makers, baking molds and trays, barbecue griddles and grills, and preparation bowls. EXAMPLES

[0389] The aims, aspects and advantages of the present invention will be better understood from the description given below of a particular embodiment of the invention presented by way of non-limiting example.

[0390] Of course, the invention is in no way limited to the embodiment described and illustrated, which has been given only by way of example. Modifications remain possible, particularly with regard to the composition of the various elements or by substitution of technical equivalents, without departing from the scope of protection of the invention.

[0391]

[0392] and counter-examples of implementation:

[0393] Metallic substrate: this is an aluminum support that has been sandblasted or shot-blasted and then subjected to a suitable surface treatment to eliminate organic contaminants.

[0394] The raw materials for the different layers are detailed below.

[0395]

[0396] Preparation of a coating according to the invention

[0397] The coating in example 1 includes:

[0398] a sol-gel base layer (3a),

[0399] a sol-gel-based layer (3c) obtained with a metal alkoxide-type precursor having an aliphatic chain comprising at least one unsaturation, and

[0400] a finishing layer (3d1) comprising a silicone elastomer obtained in particular from an organopolysiloxane carrying silyl hydride reactive functions (-Si-H).

[0401] Base layer (3a)

[0402] The base coat formulation (3a) is prepared from a three-component system: part A, part B, and part C. Part A is colloidal silica with a particle size less than 200 nm. Part B incorporates the reactive silane MTMS and the acid catalyst. Part C incorporates the pigments, fillers, solvents, wetting agent, and PDMS oil. [Table 2]

[0403] Components of layer (3a) Part Mass in g.

[0404] Colloidal silica (30%) A 41.2

[0405] MTMS B 29.1

[0406] Acetic acid B 0.9

[0407] Isopropanol C 3.3

[0408] Butylglycol C 0.9

[0409] C 1,2 Hydroxylated PDMS Oil

[0410] Black pigment C 15.5

[0411] Micro C 7.8 alumina

[0412] Wetting agent C 0.1

[0413]

[0414] TOTAL 100

[0415] The process is as follows:

[0416] Part A is agitated with a shearing blade and a speed of 1000 rpm, sufficient to obtain a net vortex.

[0417] Part B is prepared separately by mixing the silane with the acid, then introduced under stirring into part A: the MTMS hydrolysis reaction then begins, and must continue for a minimum of 2 hours.

[0418] Next, part C is added to this mixture by incorporating the components one by one, while continuing to stir. It should be noted that we can also pre-mix all the components of part C separately before adding this paste to the A+B mixture after the 2-hour reaction period.

[0419] Once all the components are mixed, stirring continues for 30 minutes, then the formulation is stored in a closed glass bottle.

[0420] We should also note, in terms of mixing process, that we can also introduce the components of part C into part A first, leave 30 minutes of stirring, then introduce part B alone and mix for 2 hours for the sol-gel reaction.

[0421] The mixture is then left at room temperature for 24 hours before application. The shelf life of this formulation is at least 48 hours.

[0422] The mixture can also be kept in the refrigerator at 5°C: in this case, its shelf life is extended to at least 72 hours.

[0423] The resulting mixture is then filtered through a 50-micron filter before being sprayed onto a sandblasted and degreased aluminum substrate, preheated to 55°C to prevent any runs during coating. A drying step at a temperature below 100°C is then carried out for the base coat (3a).

[0424] The base layer (3a) has a dry thickness of 30 to 40 microns.

[0425] Sol-gel layer (3c) according to the invention

[0426] The wet compositions are obtained from 3 parts (A, B and C) as described for the sol-gel layer (3a).

[0427] [Table 3]

[0428] Layer components (3c) Part % wet % baked

[0429] Colloidal silica (30%) A 35.0 39.7

[0430] Water B 9.0 0

[0431] VTMO B 37.0 55.8

[0432] Acetic acid B2O

[0433] Isopropanol C 8.3 0

[0434] Butylglycol C 7.1 0

[0435] Silicone oil C 1.5 4.2

[0436] Wetting agent C 0.1 0.3

[0437]

[0438] TOTAL 100 100

[0439] The resulting mixture is filtered with a 50 micron filter before being sprayed onto layer (3a).

[0440] A drying step at 80°C is carried out on layer (3c). The thickness of layer (3c) thus obtained is 15 µm.

[0441] Top coat (3d1)

[0442] The (3d1) layer is obtained after crosslinking the following composition expressed as a relative proportion by dry mass:

[0443] an organopolysiloxane bearing reactive vinyl groups (-CH=CH2): 100 parts, another organopolysiloxane bearing reactive silyl hydride groups (Si-H): 8 parts, and

[0444] a metallic catalyst: 6 parts.

[0445] The above dry composition is mixed with a solvent to obtain a dry extract of approximately 50% to 60% by mass. The (3d1) layer is applied, and the assembly is then baked at 300°C for 45 minutes. The thickness of the (3d1) layer thus obtained is 4 µm.

[0446] Example 2: Preparation of a coating according to the invention

[0447] The coating in example 2 includes:

[0448] a base layer (3a) identical to that of example 1,

[0449] a layer (3c) identical to that of example 1, and

[0450] a finishing layer (3d2) comprising an elastomeric silicone obtained from in particular an organopolysiloxane carrying reactive thiol functions (-SH).

[0451] Topcoat (3d2)

[0452] The (3d2) layer is obtained after crosslinking the following composition expressed as a relative proportion by dry mass:

[0453] an organopolysiloxane bearing reactive vinyl groups (-CH=CH2): 100 parts, another organopolysiloxane bearing reactive thiol groups (-SH): 8 parts, and

[0454] a radical initiator: 15 shares.

[0455] This dry composition above is mixed with a solvent to obtain a dry extract of approximately 50% to 60% by mass.

[0456] The (3d2) layer is applied and then the assembly is baked at 300°C for 45 minutes. The thickness of the (3d2) layer thus obtained is 4 µm.

[0457] Counterexample 1: Preparation of a coating different from that of the invention

[0458] The coating for counterexample 1 includes:

[0459] a base layer (3a) identical to that of example 1,

[0460] a layer (3c') different from that of the invention, and

[0461] a finishing layer (3d 1) identical to that of example 1.

[0462] Sol-frost layer (3c')

[0463] The wet compositions are obtained from 3 parts (A, B and C) as described for example 1.

[0464] [Table 4]

[0465] Layer components (3c') Part % wet % baked

[0466] Colloidal silica (30%) A 35.0 41.4

[0467]

[0468] Water B 9.0 0 MTMS B 37.0 53.9

[0469] Acetic acid B2O

[0470] Isopropanol C 8.3 0

[0471] Butylglycol C 7.1 0

[0472] Silicone oil C 1.5 4.4

[0473] Wetting agent C 0.1 0.3

[0474]

[0475] TOTAL 100 100

[0476] The resulting mixture is filtered with a 50 micron filter before being sprayed onto layer (3a).

[0477] A drying step at 80°C of the layer (3c') is carried out. The thickness of the layer (3c') thus obtained is 15 µm.

[0478] Once the (3d1) layer is applied, the assembly is baked at 300°C for 45 minutes. The resulting (3d1) layer has a thickness of 4 µm.

[0479] Counterexample 2: Preparation of a coating different from the present invention. The coating of counterexample 2 comprises:

[0480] a base layer (3a) identical to that of example 1,

[0481] a layer (3c') identical to that of counterexample 1, and

[0482] a finishing layer (3d2) identical to that of example 2.

[0483] BOILING WATER TEST

[0484] In order to simulate aging due to aqueous cooking, we carry out a boiling water aging test.

[0485] The test procedure is as follows:

[0486] - Wash the pan before testing with warm water, the yellow side of the sponge and detergent.

[0487] - Fill with tap water and heat until boiling.

[0488] - When boiling occurs, maintain the heating and start the timer.

[0489] - After a 2-hour boiling period: wash the item with warm water, yellow side of the sponge and detergent to remove surface limescale.

[0490] - Evaluation of non-stickiness by cooking an egg.

[0491] - Clean and restart a boiling cycle if the egg comes loose. Repeat this boiling cycle as many times as necessary until the egg no longer comes loose.

[0492] The higher the number of cycles, and therefore the number of hours, the more durable the coating is considered to be in terms of anti-stick performance.

[0493] Comparative results

[0494] The table below summarizes the tests carried out and the results in terms of durability of the anti-stick properties through a cyclic boiling test described above.

[0495] [Table 5]

[0496] Water test result

[0497] Boiling hot in hours

[0498] Example 1 50

[0499] Example 2 50

[0500] Counter-example 1 15

[0501] Counter-example 2 15

[0502]

[0503] The coating according to the invention exhibits durable anti-stick properties while remaining adherent to the substrate.

Claims

DEMANDS 1. Coated cooking element (1) for a cooking article or electrical cooking appliance, comprising a metallic substrate (2) coated on at least one face (2a) by at least the following layers and in that order from the metallic substrate (2): (3a) a sol-gel base layer; (3b) optionally one or more intermediate layer(s) which may be decorations; (3c) a sol-gel layer obtained from a sol-gel mixture (SG) comprising a metal alkoxide-type precursor having an aliphatic chain comprising at least one unsaturation and / or substituted by a thiol group, and (3d) a top layer in contact with layer (3c) and comprising an elastomeric silicone obtained from at least one organopolysiloxane bearing vinyl reactive functions (-CH=CH2) and at least one other organopolysiloxane bearing silyl hydride reactive functions (-Si-H) or thiol reactive functions (-SH), wherein, when the elastomeric silicone of layer (3d) is obtained from at least one organopolysiloxane bearing thiol reactive functions (-SH), the metal alkoxide precursor of layer (3c) has an aliphatic chain comprising at least one unsaturation and which may further be substituted by a thiol group (-SH).

2. Coated baking element (1) according to claim 1 characterized in that the metal alkoxide-type precursor of the sol-gel mixture for layer (3c) is an alkoxysilane selected from the group consisting of: a trialcoxysilane bearing an aliphatic chain comprising at least one unsaturation and / or substituted by a thiol group, a dialkoxysilane bearing one or two aliphatic chains comprising at least one unsaturation and / or substituted by a thiol group, a monoalkoxysilane bearing one, two or three aliphatic chains comprising at least one unsaturation and / or substituted by a thiol group, and their mixtures.

3. Coated cooking element (1) according to claim 1 or claim 2 characterized in that the sol-gel mixture for layer (3c) further comprises a metal alkoxide type precursor not carrying unsaturation.

4. Coated cooking element (1) according to claim 3 characterized in that the metal alkoxide type precursor not carrying unsaturation is selected from the group consisting of methyltrimethoxysilane (MTMS), tetraethoxysilane (TEOS), methyltriethoxysilane (MTES), dimethyldimethoxysilane, and mixtures thereof.

5. Coated cooking element (1) according to any one of the preceding claims characterized in that the layer (3c) comprises at least one metal oxide, preferably a colloidal metal oxide selected from colloidal silica and / or colloidal alumina and / or colloidal zirconia and / or colloidal titanium.

6. Coated cooking element (1) according to any one of the preceding claims characterized in that the layer (3c) comprises a silicone oil.

7. Coated cooking element (1) according to any one of the preceding claims, characterized in that the organopolysiloxanes bearing reactive functions of the layer (3d) are silicone oils.

8. Coated cooking element (1) according to any one of the preceding claims, characterized in that: • the thickness of layer (3a) is between 5 pm and 100 pm, preferably between 10 pm and 30 pm, • the thickness of layer(s) (3b), when present, is between 1 pm and 100 pm, preferably between 3 pm and 10 pm, • the thickness of layer (3c) is between 1 pm and 50 pm, preferably between 2 pm and 20 pm, and • The thickness of the topcoat (3d) is between 0.1 pm and 10 pm, preferably between 1 pm and 2 pm.

9. A method for manufacturing a coated cooking element (1) according to any one of the preceding claims comprising the following successive steps: i. supply of a metallic substrate (2) comprising at least one face (2a) intended to be coated, ii. possibly, pretreatment of the face (2a), iii. application of a base layer (3a) on face (2a), iv. possibly, drying of the base coat (3a), v. where applicable, application of layer(s) (3b), vi. possibly, drying of the layer(s) (3b), vii. application of the sol-gel layer (3c), viii. optionally, drying of layer (3c) and / or firing of layers (3a), (3c), and where applicable (3b), ix. application of the topcoat (3d), x. cooking of the layers and obtaining the element (1).

10. Method according to claim 9, characterized in that step x. is carried out at a temperature ranging from 150°C to 350°C for a duration of 1 min to 45 min.

11. Cooking article (100) or electric cooking appliance (200) comprising a coated cooking element (1) conforming to any one of claims 1 to 8 or capable of being obtained according to claim 9 or claim 10.

12. Culinary article (100) according to claim 11, selected from the group consisting of saucepan, frying pan, fondue or raclette pan, stockpot, wok, sauté pan, crepe pan, grill, griddle, pot, casserole dish, cooker or bread machine bowl, cooking mold, molds and baking trays, barbecue trays and grills, preparation bowls.

13. Electric cooking appliance (200) according to claim 11, selected from the group consisting of electric crepe maker, electric raclette appliance, electric fondue appliance, electric grill, electric griddle, electric cooker, bread machine, electric pressure cooker, waffle makers, rice cookers and jam makers.

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