Non-stick film comprising a decoration, cooking element comprising the film, and methods for obtaining same
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- SEB SA
- Filing Date
- 2024-08-30
- Publication Date
- 2026-07-08
Smart Images

Figure EP2024074279_06032025_PF_FP_ABST
Abstract
Description
[0001] NON-STICK FILM COMPRISING A DECORATION, COOKING ELEMENT COMPRISING SAID FILM, AND METHODS FOR OBTAINING SAME
[0002] FIELD OF THE INVENTION
[0003] The present invention relates to the field of methods for obtaining cooking elements coated with a non-stick polymeric film comprising a decoration, as well as the coated cooking elements thus obtained.
[0004] STATE OF THE ART
[0005] In the cookware industry with non-stick cooking surfaces, the performance of non-stick coatings as well as their attractiveness are major concerns.
[0006] Conventionally, a metal substrate is first formed into a cookware, and then the interior surface of the cookware is coated with the non-stick coating; the metal substrate may also be coated before being formed. The non-stick coating generally comprises one or more primer and topcoat layers applied successively using a liquid spray coating process or a powder coating process.
[0007] Obtaining a non-stick coating with decoration(s) requires the implementation of additional steps for depositing the decoration(s).
[0008] The liquid spray coating process has several disadvantages. When the metal substrate has a curved shape, it is difficult to achieve a uniform coating thickness. The liquid spray coating process also involves the use of solvents or volatile organic compounds that evaporate during the process and must be recovered and recycled. From an environmental perspective, a solvent-free and volatile organic compound-free process is preferred. Furthermore, the coating thickness is limited. Cracking is likely to occur when the coating thickness is too thick.
[0009] The powder coating process also has disadvantages. The resulting coating has pinhead-like defects, which can lead to a reduction in non-stick properties. Coatings obtained using these two processes can have significant surface roughness, which can pose cleaning problems, as some cooking residue can persist on the surface of the coating even after several washes.
[0010] In order to overcome the above-mentioned drawbacks, the state of the art describes metal substrates coated with fluorinated films by rolling.
[0011] Application KR20160099388 describes the method for obtaining a metal substrate coated with a multilayer fluorinated film. The fluorinated film is obtained by successive deposition on a support of an aqueous dispersion of the constituents of the layer (fluorinated resin and optionally an inorganic filler) which is dried and sintered. The multilayer film is then removed from its support and positioned on the metal substrate before assembly. A laminated film comprising 3 layers is described in the application. The first layer comprises a mixture of PTFE and a fluorinated resin having good flow properties. The second layer comprises a fluorinated resin and an inorganic filler present at 5 to 50% by weight of the layer. Finally, a third layer comprises PTFE and 0 to 25% by weight of an inorganic filler. These inorganic fillers can be titanium oxide or graphite and are present within the layers, thus allowing the film to be colored.
[0012] This uniform, pattern-free mass-colouring of the film is not very attractive to the user. Furthermore, the inorganic pigments used do not provide any useful functionality for the user.
[0013] STATEMENT OF THE INVENTION
[0014] There remains a need to develop processes for obtaining cooking elements comprising a metal substrate coated with a non-stick coating which can have the following advantages: the coating obtained can be of high thickness, of controlled and homogeneous thickness, which makes it possible to improve its non-stick character and increase its durability; possibly, the coating has improved resistance to mechanical stresses; the process for obtaining the coated metal substrate is a process without solvent or volatile organic compound; the cooking element thus obtained has increased attractiveness and its use is easier for the user.
[0015] The applicant has thus developed a method for manufacturing a coated cooking element by assembling by hot pressing a metal substrate and a polymeric film comprising a decoration.
[0016] The presence of a decoration helps to enhance the attractiveness of the cooking element. The decoration can also play a role other than purely aesthetic, in particular by allowing the masking of pre-existing surface defects or by minimizing, for example, the visibility of scratches generated over time by the use of the cooking element.
[0017] The decor can also help guide the user of the cooking element in its use (for example, a thermochromic decor to optimize the cooking of food).
[0018] Summary of the invention
[0019] The invention thus relates to a method for manufacturing a coated cooking element (1) comprising the following steps: i. Providing a metal substrate (2) having a face (2a), intended to be coated with a film (3); ii. Providing said film (3), said film (3) comprising:
[0020] - a layer (3a) comprising one or more semi-crystalline or amorphous thermoplastic polymers, said layer (3a) being intended to be brought into contact with said face (2a) of said metal substrate (2);
[0021] - another layer (3b) forming a cooking face (4) opposite said layer (3a), said other layer (3b) comprising one or more polymers;
[0022] - a decoration (A) comprising a pigment composition, said decoration (A) being arranged between the layer (3a) and the other layer (3b) of the film (3); iii. Positioning said film (3) so that the layer (3a) faces said face (2a) of the metal substrate (2); iv. Carrying out the assembly of said metal substrate (2) and said film (3) by hot pressing. The invention also relates to a coated cooking element (1) obtainable according to the above method.
[0023] Other aspects of the invention are as described below.
[0024] Definitions
[0025] “Room temperature” means a temperature between 18 and 30°C.
[0026] The term "film" is understood to mean, within the meaning of the present invention, an assembly consisting of one or more superimposed layers intended to be assembled with the metal substrate. The term "film" also corresponds to said assembly once assembled with the metal substrate.
[0027] The term "layer" is understood to mean, within the meaning of the present invention, a continuous or discontinuous layer. A continuous layer (or also called a monolithic layer) is a single whole forming a total flat area completely covering the surface on which it is placed. A discontinuous layer (or non-monolithic layer) may comprise several parts, thus not being a single whole.
[0028] The term "decor" or "decorative layer" means one or more continuous or discontinuous layers comprising a pigment composition. The decor may be in the form of one or more patterns, one or more colors. A decor is clearly visible to the user with the naked eye and at a normal distance from the household item.
[0029] Overlapping layers are defined as partially or completely superimposed layers. These layers may be in the form of decoration with partially overlapping patterns, for example concentric discs.
[0030] "Adjacent layers" are understood to mean non-overlapping layers. These layers can be presented in the form of decoration with identical or different non-overlapping patterns, preferably distributed evenly.
[0031] The term "thermostable pigment, pigment compound or pigment composition" means a pigment, pigment compound or pigment composition which does not exhibit a change in color when subjected to an increase in temperature in a given temperature range or which exhibits a change in hue when subjected to an increase in temperature in a given temperature range which is so small that this change in hue is not visible to the user with the naked eye and at a conventional operating distance.
[0032] Preferably, the thermostable pigments have an AE* color difference between 25°C and 200°C of less than 10.
[0033] AE* being defined by the CIE1976 formula in the CIELAB color space:
[0034] Lï*, a^ and b^ characterizing the L*a*b* values of said compound at room temperature
[0035] L2*, a2* and b2* characterizing the L*a*b* values of said compound at 150°C.
[0036] By "the colors are identical" we mean indistinguishable by the user with the naked eye and at a normal viewing distance.
[0037] For the purposes of the present invention, the term "pigment, pigment compound or thermochromic pigment composition" means a pigment, pigment compound or pigment composition which changes color depending on the temperature in a given temperature range, this change being reversible. This color change is visible to the user with the naked eye and at a conventional operating distance.
[0038] By pigment composition is meant a composition comprising at least one pigment. The composition may be in the form of particles of said at least one pigment.
[0039] The expression "thermochromic compound" is understood to mean, within the meaning of the present invention, a mineral or organic compound, which exhibits a reversible change in color upon increasing temperature. The progressive and reversible thermochromic character of these semiconductor compounds is linked to the reduction in the width of the forbidden band of the semiconductor due to the expansion of the material. Indeed, the periodicity of the network of anions and cations leads to the gathering of energy levels into energy bands. The filled energy band with the highest energy is called the valence band and the empty energy band with the lowest energy is called the conduction band. Between these two bands, there is a forbidden band called the gap.The color of a semiconductor material can come from the presence of a charge transfer which corresponds to the passage of an electron either from a valence band to a conduction band on the same atom, or commonly from the orbital of an anion to the orbital of a cation (interatomic photonic absorption).
[0040] The term "temperature reference pigment composition" means a composition comprising a pigment which, at a given temperature, makes it possible to indicate to the user that the optimum operating temperature has been reached. Advantageously, this indication can be made by comparing the colours of a thermochromic pigment and the temperature reference pigment composition. Either the optimum operating temperature is reached when the colours are identical, or the optimum operating temperature is reached when the colours are visually very different.
[0041] The optimum operating temperature can be achieved when the color of the temperature reference pigment composition corresponds to a color indicated in the user guide for the household article or electrical appliance comprising a film according to the invention or to a color indicated on a color scale provided to the user with said article.
[0042] The temperature reference pigment composition can be thermochromic or thermostable.
[0043] The temperature reference pigment composition may be, for example, a cooking temperature reference pigment composition or an indication of the risk of overheating.
[0044] In the fields of application envisaged for the present invention, in the case of a culinary article, the optimal conditions are reached when the coated cooking element reaches a temperature suitable for cooking food, preferably between 100 and 250°C, preferably between 150°C and 200°C.
[0045] For the purposes of the present invention, the term "aluminum alloy" means an aluminum alloy of series 1000, 2000, 3000, 4000, 5000, 6000, 7000 and 8000.
[0046] DESCRIPTION OF THE FIGURES Figure 1: Example of embodiment of a coated cooking element (1) according to the method of the invention, comprising a film (3), a metal substrate (2) and a decoration (A) and another decoration (B), the decoration (A) and the other decoration (B) being in the form of adjacent non-overlapping patterns (Figure 1A); in the form of partially overlapping patterns (Figure 1B); in the form of overlapping patterns (Figure 1C).
[0047] In Figures 1A / B / C, the left views represent the decoration (A) and the other decoration (B) seen from above the coated cooking element (1) from the side of the film (3). The right views represent the coated cooking element (1) shown in section.
[0048] DETAILED DESCRIPTION OF THE INVENTION
[0049] Manufacturing process of a coated cooking element:
[0050] The inventors developed a manufacturing process that met the expressed needs.
[0051] The invention relates to a method for manufacturing a coated cooking element (1) comprising the following steps: i. Providing a metal substrate (2) having a face (2a), intended to be coated with a film (3); ii. Providing said film (3), said film (3) comprising: a layer (3a) comprising one or more semi-crystalline or amorphous thermoplastic polymers, said layer (3a) being intended to be brought into contact with said face (2a) of said metal substrate (2); another layer (3b) forming a cooking face (4) opposite said layer (3a), said other layer (3b) comprising one or more polymers; a decoration (A) comprising a pigmentary composition, said decoration (A) being arranged between the layer (3a) and the other layer (3b) of the film (3); iii. Positioning said film (3) so that the layer (3a) is opposite said face (2a) of the metal substrate (2); iv.Production of the assembly of said metal substrate (2) and said film (3) by hot pressing.
[0052] Metal substrate (2) used in step i of the process As metal substrates (2) which can be used in the context of the invention, mention may advantageously be made of substrates made of aluminum, stainless steel, cast iron or aluminum, or titanium or copper.
[0053] For the purposes of the present invention, aluminum means a metal consisting of 100% aluminum or an aluminum alloy.
[0054] Advantageously, the metal substrate (2) is an aluminum substrate, a stainless steel substrate or a multi-layer metal substrate. The metal substrate (2) may be a two-layer or three-layer substrate, these multi-layers being able to be obtained for example by co-rolling, by hot diffusion under load (solid state bonding) or by hot or cold impact bonding.
[0055] Preferably, the metal substrate (2) comprises alternating layers of metal and / or metal alloy.
[0056] According to one embodiment, the metal substrate (2) is an aluminum alloy substrate, a stainless steel substrate or a multi-layer metal substrate whose face (2a) is made of aluminum alloy or stainless steel.
[0057] Preferably, the metal substrate (2) is an aluminum substrate.
[0058] Advantageously, the thickness of the metal substrate (2) is between 0.5 mm and 10 mm.
[0059] Advantageously, the face (2a) of the metal substrate (2) has undergone a surface treatment prior to assembly with the film (3) making it possible to improve the adhesion of said film to said substrate.
[0060] According to one embodiment, the surface of the face (2a) of the metal substrate (2) has undergone a surface treatment, said surface treatment being a chemical attack, brushing, hydration, sandblasting, shot blasting, a physicochemical treatment of the plasma or corona or laser type, a chemical activation or a combination of these different techniques. Advantageously, the average arithmetic roughness Ra of the surface of the face (2a) of the metal substrate (2) is greater than or equal to 1 pm, preferably greater than or equal to 2 pm.
[0061] Advantageously, the average arithmetic roughness Ra of the surface of the face (2a) of the metal substrate (2) is less than or equal to 20 pm.
[0062] Advantageously, the average arithmetic roughness Ra of the surface of the face (2a) of the metal substrate (2) ranges from 2 pm to 10 pm.
[0063] The arithmetic mean roughness Ra is measured using a roughness meter according to ISO 4287. Ra represents the arithmetic mean of the deviations from the mean. The surface topography can be studied in particular with a profilometer with a probe equipped with a fine stylus equipped with a diamond tip, or with an optical metrology device such as Altisurf®, in which a chromatic confocal sensor allows a contactless measurement. The study of this surface topography makes it possible to define the arithmetic mean roughness Ra.
[0064] Film (3) used in step ii of the process
[0065] The film (3) comprises: a layer (3a) comprising one or more semi-crystalline or amorphous thermoplastic polymers, said layer (3a) being intended to be brought into contact with said face (2a) of said metal substrate (2); another layer (3b) forming a cooking face (4) opposite said layer (3a), said other layer (3b) comprising one or more polymers.
[0066] According to one embodiment, the semi-crystalline or amorphous thermoplastic polymer(s) of the layer (3a) are chosen from: polytetrafluoroethylene (PTFE), copolymers of tetrafluoroethylene and perfluoropropylvinylether (PFA), copolymers of tetrafluoroethylene and hexafluoropropene (FEP), polyvinylidene fluoride (PVDF), copolymers of tetrafluoroethylene and polymethylvinylether (MVA), terpolymers of tetrafluoroethylene, polymethylvinylether and fluoroalkylvinylether (TFE / PMVE / FAVE), ethylene tetrafluoroethylene (ETFE), and mixtures thereof, polyarylether ketones (PAEK), including polyether ketone (PEK), polyether ether ketone (PEEK), polyether ketone ketone (PEKK), polyether ether ketone ketone (PEEKK), polyether ketone ether ketone ketone (PEKEKK), preferably polyether ether ketone (PEEK), polyamideimide (PAI), polyimide (PI), polyetherimide (PEI), polybenzymidazole (PBI), poly(phenylene oxide) (PPO),poly(arylethersulfone) (PAES) polymers including polyethersulfone (PES), polyphenylene ether sulfone (PPSU), poly(arylene sulfides) (PAS) including polyphenylene sulfide (PPS), liquid crystal polymers, polyphthalamide (PPA), and mixtures thereof.,
[0067] According to one embodiment, the polymer(s) of the other layer (3b) are chosen from: polytetrafluoroethylene (PTFE), copolymers of tetrafluoroethylene and perfluoropropylvinylether (PFA), copolymers of tetrafluoroethylene and hexafluoropropene (FEP), polyvinylidene fluoride (PVDF), copolymers of tetrafluoroethylene and polymethylvinylether (MVA), terpolymers of tetrafluoroethylene, polymethylvinylether and fluoroalkylvinylether (TFE / PMVE / FAVE), ethylene tetrafluoroethylene (ETFE), and mixtures thereof;preferably PTFE, polyarylether ketones (PAEK), including polyether ketone (PEK), polyether ether ketone (PEEK), polyether ketone ketone (PEKK), polyether ether ketone ketone (PEEKK), polyether ketone ether ketone ketone (PEKEKK), preferably polyether ether ketone (PEEK), polyamideimide (PAI), polyimide (PI), polyetherimide (PEI), polybenzymidazole (PBI), poly(phenylene oxide) (PPO), poly(arylethersulfone) polymers (PAES) including polyethersulfone (PES), polyphenylene ether sulfone (PPSU), poly(arylene sulfides) (PAS) including polyphenylene sulfide (PPS), liquid crystal polymers, polyphthalamide (PPA), silicone resins, and mixtures thereof, preferably mixtures of PTFE and PEEK. The film (3) further comprises a decoration (A) comprising a pigmentary composition, said decoration (A) being arranged between the layer (3a) and the other layer (3b) of the film (3).;
[0068] According to one embodiment, the other layer (3b) is a continuous surface layer, transparent or translucent. By transparent is meant the characteristic of the other layer (3b) of allowing light to pass through it. By translucent is meant the characteristic of the other layer (3b) of allowing light to pass through it without clearly distinguishing the underlying decoration. The other layer (3b) thus leaves excellent visibility or partial visibility of the underlying decoration layer while protecting it from mechanical attack and conferring its non-stick properties to the coating of the coated cooking element (1).
[0069] The pigment composition of the decoration (A) is a thermostable or thermochromic composition. Advantageously, the pigment composition of the decoration (A) is a thermochromic composition as described in the 'definitions' section.
[0070] Advantageously, the film (3) further comprises another decoration (B) comprising another pigmentary composition, said other decoration (B) being arranged between the layer (3a) and the other layer (3b) of the film (3).
[0071] By other pigment composition, it is understood that the pigment composition of the decoration (B) is different from that of the decoration (A).
[0072] If decoration (A) and decoration (B) comprise a single pigment, the pigment of the pigment composition of decoration (B) is different from the pigment of the pigment composition of decoration (A).
[0073] If the decoration (A) and the decoration (B) comprise several pigments, the mixture of pigments of the pigment composition (B) differs by at least one pigment from the mixture of pigments of the pigment composition of the decoration (A).
[0074] According to one embodiment, the other pigment composition of the other decoration (B) is a thermochromic pigment composition and the pigment composition of the decoration (A) is a temperature reference pigment composition. Preferably, the thermochromic pigment(s) of the thermochromic pigment compositions are chosen from the group consisting of Bi2O3, Fe2O3, V2O5, WO3, CeO2, ln2O3, Yi )8 4Cao ) i6Tii ) 84Vo,i60i,84> Agi, (Bi 1.x HAS x )(V 1.y M y )O4with x is equal to 0 or x is between 0.001 and 0.999, y is equal to 0 or y is between 0.001 and 0.999,
[0075] A and M are selected from the group consisting of nitrogen, phosphorus, an alkali metal, a n-alkali metal, a transition metal, a poor metal, a metalloid or a lanthanide,
[0076] A and M are different from each other.
[0077] Knowing that A and M are different from each other, when:
[0078] - A is an alkali metal, it can be chosen from Li, Na, K, Rb, Cs,
[0079] - M is an alkali metal, it can be chosen from Li, Na, K, Rb, Cs,
[0080] - A is a noterous alkali metal, it can be chosen from Be, Mg, Ca, Sr, Ba,
[0081] - M is a noterous alkali metal, it can be chosen from Be, Mg, Ca, Sr, Ba,
[0082] - A is a transition metal, it can be chosen from Sc, Ti Cr, Mn, Fe, Co, Ni, Cu, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Ta, W, Ir,
[0083] - M is a transition metal, it can be chosen from Sc, Ti Cr, Mn, Fe, Co, Ni, Cu, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Ta, W, Ir,
[0084] - A is a poor metal, it can be chosen from Al, Zn, Ga, In, Sn,
[0085] - M is a poor metal, it can be chosen from Al, Zn, Ga, In, Sn,
[0086] - A is a metalloid, it can be chosen from B, Si, Ge, Sb,
[0087] - M is a metalloid, it can be chosen from B, Si, Ge, Sb,
[0088] - A is a lanthanide, it can be chosen from La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu,
[0089] - M is a lanthanide, it can be chosen from La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu.
[0090] Preferably, A and M different from each other are B and / or Mg.
[0091] Preferably, the pigment (Bi 1.x HAS x )(V 1.y M y )O4 has a monoclinic scheelite crystallographic form at room temperature.
[0092] Preferably, x and y are 0, i.e. the pigment (Bi 1.x HAS x )(V 1.y M y)O4 is Bismuth Vanadate (BiVO4). Advantageously, a BiVO4 with a monoclinic scheelite crystallographic structure at room temperature is used. Bismuth Vanadate is a yellow inorganic compound, with the formula BiVO4, widely used for its coloristic properties and its lack of toxicity. Registered in the Colour Index International database as QI Pigment Yellow 184, it is notably marketed by the companies Heubach (Vanadur®), BASF (Sicopal®), FERRO (Lysopac) and Bruchsaler Farbenfabrik (Brufasol®).
[0093] Preferably, the thermostable pigment(s) of the thermostable pigment compositions is / are chosen from the group consisting of:
[0094] - Yellow titanium rutile pigments,
[0095] - Yellow pigments derived from bismuth, for example selected from stabilized bismuth vanadates (Pyi84),
[0096] - Red pigments, for example selected from perylene red (for example PR149, PR178 and PR224), iron oxide,
[0097] - Orange pigments of the bismuth oxyhalides type (PO 85 ) ,
[0098] - Bismuth vanadate orange pigments (PO 86 ) ,
[0099] - Zinc tin titanium orange pigment (PO 82 ) ,
[0100] - Cerium sulfide orange pigment (PO 75 ; PO 78 ),
[0101] - Orange-yellow pigment of the antimony titanium chrome rutile type (PBr24),
[0102] - Orange-yellow pigment of tin and zinc rutile type (Py 216 ) ,
[0103] - Orange-yellow pigment of niobium oxide tin zinc sulfide (Py 227 ),
[0104] - Orange-yellow pigment of double oxides of tin and niobium,
[0105] - Co3(P04)2,
[0106] - LiCoP04,
[0107] ■ CoAl204,
[0108] ■ Cr2O3,
[0109] - TiO2,
[0110] - Black pigment PBk28 (Copper chromite black spinel),
[0111] - and their mixtures.
[0112] Each of the decoration (A) and the other decoration (B) can appear as adjacent, non-overlapping patterns. For example, each decoration is represented by different geometric patterns distributed uniformly over the entire surface and alternating with respect to each other (see Figure 1 A).
[0113] According to another embodiment, each of the decoration (A) and the other decoration (B) is in the form of overlapping or partially overlapping patterns. For example, each decoration is represented by different geometric patterns distributed uniformly over the entire surface and partially overlapping (see Figure 1B).
[0114] Preferably, the decoration (A) and the other decoration (B) are overlapping, either because one of the two decorations is a continuous layer and the other decoration covers it in the form of patterns, or because the decoration (A) and the other decoration (B) are in the form of two overlapping patterns (see Figure 1C).
[0115] The “temperature reference pigment composition” of the decoration (A) may comprise a pigment which has: the same colour as the thermochromic pigment of the other pigment composition of the other decoration (B), at the optimum temperature of use, o either because this pigment has at room temperature the same colour as the thermochromic pigment of the other decoration (B) at the optimum temperature of use, and does not change colour with the temperature, o either because this pigment has at room temperature a colour different from that of the thermochromic pigment of the other decoration (B) and which evolves to the same colour as the thermochromic pigment at the optimum temperature of use, a colour very different from that of the thermochromic pigment of the other decoration (B) at the optimum temperature of use, whether or not this pigment changes colour with the change in temperature.
[0116] According to one embodiment, the decoration (A) and the other decoration (B) have distinct colors at room temperature and the same color at a temperature between 100°C and 250°C, preferably between 150°C and 200°C.
[0117] According to another embodiment, the decoration (A) and the other decoration (B) have colors that cannot be distinguished at room temperature and different colors at a temperature between 100°C and 250°C, preferably between 150°C and 200°C.
[0118] The decor (A) and the other decor (B) optionally comprise one or more fluoropolymers. The decor (A) and the other decor (B) optionally comprise additives. Said additives are selected from the group consisting of solvents, thickeners, antifoam agents, pH adjusters, wetting agents and dispersants.
[0119] The additives are chosen to optimize the quality of the deposit on the polymer layer on which they are deposited.
[0120] Said solvents are preferably chosen from the group consisting of: water, alcohols, diols, glycols, esters.
[0121] Said thickeners are preferably chosen from the group consisting of acrylic-based or polyurethane-based copolymer, cellulose, fumed silica, silicone resin.
[0122] Said anti-foaming agents are preferably chosen from the group consisting of polysiloxane, modified polysiloxane, polyether-siloxane copolymer, amphiphilic polymers, silicone, aliphatic mineral oil.
[0123] The said pH adjusters are preferably chosen from the group consisting of Bronsted bases: ammonia, amines (triethylamine, triethanolamine, etc.), hydroxides (soda, potash, etc.), carbonates.
[0124] Said wetting agents and dispersants are preferably chosen from the group consisting of high molecular weight fatty acid derivatives, modified polyether, surfactants, modified polyacrylate.
[0125] According to one embodiment, the film (3) further comprises at least one intermediate layer (3c) positioned between the layer (3a) and the other layer (3b), said intermediate layer (3c) comprising one or more polymers chosen from:
[0126] - polytetrafluoroethylene (PTFE), copolymers of tetrafluoroethylene and perfluoropropylvinylether (PFA), copolymers of tetrafluoroethylene and hexafluoropropene (FEP), polyvinylidene fluoride (PVDF), copolymers of tetrafluoroethylene and polymethylvinylether (MVA), terpolymers of tetrafluoroethylene, polymethylvinylether and fluoroalkylvinylether (TFE / PMVE / FAVE), ethylene tetrafluoroethylene (ETFE), and mixtures thereof; preferably copolymers of tetrafluoroethylene and perfluoropropylvinylether (PFA) and PTFE; preferably PTFE, - polyarylether ketones (PAEK), including polyether ketone (PEK), polyether ether ketone (PEEK), polyether ketone ketone (PEKK), polyether ether ketone ketone (PEEKK), polyether ketone ether ketone ketone (PEKEKK), preferably polyether ether ketone (PEEK),
[0127] - polyamideimide (PAI), polyimide (PI), polyetherimide (PEI), polybenzymidazole (PBI),
[0128] - poly(phenylene oxide) (PPO), poly(arylethersulfone) polymers (PAES) including polyethersulfone (PES), polyphenylene ether sulfone (PPSU), poly(arylene sulfides) (PAS) including polyphenylene sulfide (PPS), liquid crystal polymers,
[0129] - polyphthalamide (PPA),
[0130] - silicone resins,
[0131] - and their mixtures, preferably mixtures of polyarylether ketones (PAEK) and PTFE, preferably mixtures of PEEK and PTFE, PTFE being particularly preferred.
[0132] Advantageously, the silicone resin(s) of the other layer (3b) and, where appropriate, of the intermediate layer (3c), is / are chosen from the group consisting of methyl silicone and / or phenyl silicone and / or methyl-phenyl-silicone resins, methyl silicone-polyester resin (copolymers), phenyl silicone-polyester resin (copolymers), methyl-phenyl-silicone-polyester resin (copolymers), silicone-alkyd resin (copolymers), modified silicone resin and mixtures thereof.
[0133] In the text of the description, the expression "silicone resin" is used interchangeably to refer to the silicone before its crosslinking or after its crosslinking. In the text of the description, the expression "silicone" designates an organopolysiloxane material. Crosslinking is the step which makes it possible to transform the silicone into an insoluble material, for example by polyaddition, polycondensation or dehydrogenation. Crosslinking is carried out from precursors which are generally silicone oils or resins, which crosslink to obtain a three-dimensional network forming a material called silicone resin, in the description.
[0134] This crosslinking can be done by thermal activation, or chemical activation using a catalyst, such as platinum. The silicone resins can be obtained from precursors, advantageously soluble in a solvent or in emulsion in water, such as oils or crosslinkable resins, in particular chosen from: a silicone hydride, a silicone oil resin comprising at least one vinyl group (-CH=CH2), a silicone or silicone-polyester resin (copolymer) comprising at least one alkoxy group, for example methoxy or ethoxy, and / or a silicone or silicone-polyester resin (copolymer) comprising at least one alkoxy group, in particular ethoxy, or a hydroxy group and mixtures thereof. These precursors have the capacity to crosslink in order to obtain a silicone resin which is characterized by its insolubility and its substantially solid form.
[0135] Advantageously, these precursors are polymeric or oligomeric, either in the form of silicone oils with a variable degree of branching, or in the form of silicone resins with a variable degree of pre-crosslinking or copolymers of silicone resins such as silicone-polyester, silicone-alkyd, silicone-polyurethane, silicone-epoxy resins, or in the form of a mixture of silicone oils, silicone resins and copolymers of silicone resins. The silicon atoms may be substituted by alkyl (in particular methyl) or aryl (in particular phenyl) groups or mixtures thereof. The oils or resins preferably comprise one or more (2, 3 or more) hydroxy or alkoxy (in particular methoxy, ethoxy, butoxy) functional groups as substituents of silicon atoms.
[0136] Advantageously, the silicone resin(s), obtained after crosslinking their precursors, i.e. crosslinked, is / are selected from the group consisting of methyl silicone and / or phenyl silicone and / or methyl-phenyl-silicone resins, methyl silicone-polyester resin (copolymers), phenyl silicone-polyester resin (copolymers), methyl-phenyl silicone-polyester resin (copolymers), silicone-alkyd resin (copolymers), modified silicone resin and their mixtures.
[0137] Advantageously, the silicone resin(s) is / are chosen from the group consisting of methyl silicone and / or phenyl silicone and / or methyl-phenyl-silicone resins, methyl silicone-polyester resin (copolymers), phenyl silicone-polyester resin (copolymers), methyl-phenyl silicone-polyester resin (copolymers), silicone-alkyd resin (copolymers), modified silicone resin and mixtures thereof.
[0138] Silicone resins can be obtained from precursors, notably chosen from: a silicone hydride, a silicone resin comprising at least one vinyl group (-CH=CH2), a silicone-polyester resin (copolymer) comprising at least one methoxy group, and / or a silicone-polyester resin (copolymer) comprising at least one ethoxy group, and mixtures thereof.
[0139] The silicone resin forms a network which may consist of a combination of 4 simple organosiloxane units called M, D, T and Q depending on the degree of substitution by oxygen of the silicon atom, as described in the following table, where R is an organic substituent described below.
[0140] [Table 1]
[0141] The organopolysiloxane material or polymer is obtained by crosslinking from precursors which can be monomeric or polymeric, or intermediately which can be oligomeric. The organopolysiloxane polymer can also be obtained from a mixture of these different kinds of precursors. When the network contains a higher number of T and Q units, than D, the crosslinking density is higher. The distribution between the M, D, T and Q units depends on the chemical structure of the precursors, in particular on this M, D, T, Q distribution within the precursors.
[0142] The polymeric precursors are organopolysiloxanes. These macromolecules are formed from M, D, T, and / or Q units as described in the table, where R is independently an alkyl group, in particular methyl, or aryl group, in particular phenyl, different natures of R being able to be present on the same macromolecule.
[0143] Organopolysiloxanes can be either linear or slightly branched (majority of D groups), or branched or highly branched (majority of T and Q groups). Linear or lightly branched organopolysiloxanes are generally liquid, more or less viscous at room temperature, and are called silicone oils. Branched or highly branched (pre-crosslinked) organopolysiloxanes form a network at the level of the individual macromolecule and are called silicone resins. At room temperature, the resins are substantially in solid form, or in liquid form, provided in particular that they have a fairly low molecular weight, in the form of a solution in a solvent or in the form of an aqueous emulsion. They can be copolymerized with organic polymers or oligomers not containing silicon, chosen in particular from polyesters, acrylics, alkyds, polyurethanes, epoxy resins.
[0144] When the crosslinking is a hydrolysis-polycondensation: it is carried out thanks to the reactive hydroxy or alkoxy functions, in particular methoxy, ethoxy or butoxy, present on the organopolysiloxane.
[0145] When the crosslinking is a polyaddition (or hydrosilylation): it is carried out by reaction between the reactive vinyl functions (-CH=CH2) present on one of the organopolysiloxanes and the reactive silyl hydride functions (Si-H) present on the other organopolysiloxane mixed with the first.
[0146] All these reactive functions are present on each organopolysiloxane in number of at least one and can be present in number of 2, 3, or more ... as much as the molecular structure allows. Silicone oils containing at least one reactive function are called "reactive oils". The reactive functions can be found either at the end of the macromolecular chain (termination), or distributed over the chain.
[0147] Silicone-polyester resins in particular have silicone / polyester mass ratios of, for example, 90 / 10, 80 / 20, 70 / 30, 60 / 40, 50 / 50, 40 / 50, 30 / 70, 20 / 80, 10 / 90, advantageously between 80 / 20 and 50 / 50.
[0148] Linear PDMS silicone oils, pure or pre-emulsified in water, are characterized firstly by their molecular mass, which is a direct increasing function of the viscosity of the pure oil. They are then characterized by the presence or absence of reactive functions, for example hydroxyls on the silicon atoms (silanol), their number and their location on the molecular chain. For example, reactive oils with viscosities between 50 and 20,000 mPa.s, and in particular between 300 and 5,000 mPa.s, can be used, having at least one reactive function, preferably at least 2, which can be placed at the end of the chain.
[0149] Polymer precursors reacting by polyaddition may include, for example, polymethylhydrosiloxane, vinylmethylsiloxane, vinyl-terminated polydimethylsiloxane (PDMS), in particular linear, vinyl-terminated diphenylsiloxane-dimethylsiloxane copolymers, hydride-terminated polydimethylsiloxanes, hydride-terminated polyphenylmethylsiloxanes, cyclic vinylmethylsiloxane, vinyl-MQ resin, trimethylsilyl-terminated polymethylhydrosiloxane, trimethylsiloxane-terminated dimethylsiloxane copolymer, MQ resin hydride, and the like, as well as combinations thereof.
[0150] Polymeric precursors reacting by hydrolysis-polycondensation, whether silicone resins or silicone oils, may include, for example, poly(methylsilsesquioxanes), poly(propylsilsesquioxanes), poly(phenylsilsesquioxanes), polydimethylsiloxane (PDMS), trimethylsilyl-terminated polydimethylsiloxane (PDMS), hydroxyl-terminated polydimethylsiloxane (PDMS), silanol-terminated polydimethylsiloxane (PDMS), silanol-terminated polyphenylsiloxane (PDMS), silanol-terminated diphenylsiloxane-dimethylsiloxane copolymer, poly(2-acetoxyethylsilsesquioxanes), organo-modified alkoxysilanes and their oligomers, and all similar macromolecules and their mixtures.
[0151] The organopolysiloxane material or polymer may also be obtained by crosslinking a mixture of one or more monomeric precursors and one or more polymeric precursors as described above, as well as one or more oligomeric precursors which may be linear, branched or cyclic. These oligomeric precursors have a lower molecular weight than the polymeric precursors. Polymeric and / or oligomeric precursors comprising a number of reactive functions as described above greater than 2, advantageously much greater than 2, may be added to the mixture as a “co-binder” in order to promote a high crosslinking density of the organopolysiloxane polymer finally obtained.
[0152] Monomeric, oligomeric and / or polymeric precursors, in particular silicone resins, copolymerized or not with an organic polymer, act as a polymeric binder in order to obtain the solid organopolysiloxane polymer combined with the thermoplastics of each layer. Organopolysiloxane precursors of the silicone oil type can be considered as additives if they are added in small quantities (generally between 0.1 and 5% in dry weight) in the entire formula of a layer, independently of the other components for the formation of the solid organopolysiloxane polymer.
[0153] Crosslinking may require a catalyst:
[0154] In the case of crosslinking organopolysiloxanes by hydrolysis-polycondensation, the formula may include a metal catalyst, such as, for example, metal complexes based on platinum, tin, zinc, zirconium and cerium, in particular platinum-cyclovinylmethyl-silxane complexes, tin ethyl hexanoate, zinc ethylhexanoate, zirconium ethylhexanoate, cerium ethylhexanoate, and tin dibutyl laurate.
[0155] In the case of crosslinking of organopolysiloxanes by hydrosylilation, the addition of a catalyst may be necessary: this may be, for example, platinum or a suitable platinum-based catalyst such as the Karstedt catalyst or the Ashbys catalyst.
[0156] A crosslinking agent, for example carrying Si-H bonds, may be present.
[0157] The decoration (A), and if applicable the other decoration (B), can be positioned between the layer (3a) and an intermediate layer (3c), or between two intermediate layers (3c), or between an intermediate layer (3c) and the other layer (3b).
[0158] The film (3) may also further comprise at least one filler and / or at least one reinforcement.
[0159] As fillers which can be used in the present invention, mention may in particular be made of metal oxides, metal carbides, metal oxynitrides, metal nitrides, silicas and their mixtures.
[0160] These fillers may be present in one or more layers of the film (3) or in each of the layers of the film (3).
[0161] Reinforcements that can be used in the present invention include mineral or metal reinforcement of the fiber type, metal mesh, fiberglass material or fabric. The reinforcement may also consist of a non-fluorinated polymer with high thermomechanical properties of the polyaryletherketone (PEAK) type, such as polyetheretherketone (PEEK), or polyamide-imide (PAI). The reinforcement may be in the form of a layer of film (3) positioned between the layer (3a) and the other layer (3b) forming the cooking face.
[0162] In order to improve the adhesion of the film (3) and the metal substrate (2), the layer (3a) of the film (3) coming into contact with the face (2a) of the metal substrate (2) during step (v) may have undergone a mechanical or chemical surface treatment. This surface treatment may be a chemical attack, brushing, hydration, sandblasting, shot blasting, a physicochemical treatment of the plasma or corona or laser type, a chemical activation or a combination of these different techniques.
[0163] According to one embodiment, the thickness of the layer (3a) and the thickness of the other layer (3b) are each between 5 pm and 500 pm, preferably between 25 pm and 150 pm.
[0164] The measurement of the thickness of the film layer(s) (3) is carried out at 20 random points on the film section. The average thickness is obtained by averaging these 20 measurements.
[0165] According to one embodiment, the thickness of the layer (3a) and the thickness of the other layer (3b), after assembly of the film (3) and the metal substrate (2), are each between 5 pm and 500 pm, preferably between 25 pm and 150 pm.
[0166] The measurement of the layer(s) of the film (3) of the coated cooking element (1) according to the invention is carried out at 20 random points on the section of the coated substrate. The average thickness is obtained by averaging these 20 measurements.
[0167] Generally, the film (3) of the coated cooking element (1) completely covers the face (2a) of the metal substrate (2), but it can be envisaged that only a part of the metal substrate (2) is covered.
[0168] In the embodiment illustrated in Figure 1, the film (3) comprises 2 layers (layer (3a) and the other layer (3b)).
[0169] The melting point of semi-crystalline thermoplastic polymers and the glass transition temperature (Tg) of amorphous thermoplastic polymers in the film (3) can be determined by thermal analysis methods such as Differential Thermal Analysis (DSC) or Dynamic Mechanical Analysis (DMA).
[0170] Step iii
[0171] Before assembly in step iv, the film (3) is positioned above the metal substrate (2) so that its layer (3a) faces the face (2a) of the metal substrate (2).
[0172] Step iv
[0173] Step iv. of assembling the metal substrate (2) and the film (3) is carried out by hot pressing.
[0174] Hot pressing means any method for assembling a metal substrate and a polymer film by applying a high temperature, generally higher than the lowest temperature among the melting points of the semi-crystalline thermoplastic polymers and the glass transition temperatures (Tg) of the amorphous thermoplastic polymers of the layer (3a) at the time of assembly, and a high pressure, generally higher than a few MPa, for a sufficient time, varying from less than one second to a few minutes.
[0175] The assembly can be carried out by thermal compression, in a static press or between rollers (roll-to-roll process). The pressures applied by thermal compression are generally a few MPa. The processing temperature is generally limited by the degradation temperature of the polymer film to be assembled.
[0176] The assembly can be carried out by hot stamping. In this case, the pressures applied are higher than with the thermal compression process, of the order of a few hundred MPa, and the stamping time is very short, typically of the order of a few seconds, which allows the implementation of higher temperatures.
[0177] Let us also mention, without being limiting, assembly by solid state bonding. Advantageously, the temperature of the film (3) at the end of step iv. of assembly of said film (3) and the metal substrate (2), that is to say when the assembly of the film (3) and the metal substrate (2) is no longer maintained under pressure, is lower than the lowest temperature among the melting points of the semi-crystalline thermoplastic polymers and the glass transition temperatures (Tg) of the amorphous thermoplastic polymers of the layer (3a).
[0178] After assembly, the metal substrate (2) coated with the film (3) is left to cool to room temperature in order to obtain maximum adhesion between the metal substrate (2) and the film (3).
[0179] The metal substrate (2) coated with the film (3) can then be shaped at the end of step iv.
[0180] Another object of the invention thus relates to a method of shaping a coated cooking element as described above comprising a step (E1) of stamping the coated cooking element (1) obtained at the end of step (iv).
[0181] The shaping method may further comprise a step (E2) of stretching the coated cooking element (1) obtained at the end of step (E1).
[0182] According to one embodiment, the coated cooking element (1) shaped has a base surrounded by a side wall and is such that the decoration (A) and where appropriate the other decoration (B) are arranged on said base.
[0183] Coated cooking element (1):
[0184] Another object of the invention relates to a coated cooking element (1) obtainable according to the method described above.
[0185] The coated cooking element (1) according to the method of the invention can form a cooking container in a culinary article chosen from the group consisting of saucepan, frying pan, skillets or fondue or raclette pots, stewpan, wok, sauté pan, crepe maker, grill, griddle, pot, casserole dish, cooking mold. The coated cooking element (1) according to the method of the invention can form a cooking container in an electric cooking appliance chosen from the group consisting of electric crepe maker, electric raclette appliance, electric fondue appliance, electric grill, electric griddle, electric cooker, food processor, bread maker. Thus the culinary article can form a cooking accessory for an electric cooking appliance.
Claims
CLAIMS 1. A method of manufacturing a coated cooking element (1) comprising the following steps: i. Providing a metal substrate (2) having a face (2a), intended to be coated with a film (3); ii. Providing said film (3), said film (3) comprising: - a layer (3a) comprising one or more semi-crystalline or amorphous thermoplastic polymers, said layer (3a) being intended to be brought into contact with said face (2a) of said metal substrate (2); - another layer (3b) forming a cooking face (4) opposite said layer (3a), said other layer (3b) comprising one or more polymers; - a decoration (A) comprising a pigment composition, said decoration (A) being arranged between the layer (3a) and the other layer (3b) of the film (3); iii. Positioning said film (3) so that the layer (3a) faces said face (2a) of the metal substrate (2); iv. Carrying out the assembly of said metal substrate (2) and said film (3) by hot pressing.
2. Method for manufacturing a coated cooking element (1) according to claim 1, characterized in that said film (3) further comprises another decoration (B) comprising another pigment composition, said other decoration (B) being arranged between the layer (3a) and the other layer (3b) of the film (3).
3. Method for manufacturing a coated cooking element (1) according to claim 2, characterized in that the other pigment composition of the other decoration (B) is a thermochromic pigment composition and in that the pigment composition of the decoration (A) is a temperature reference pigment composition.
4. Method of manufacturing a coated cooking element (1) according to claim 2 or claim 3, characterized in that the decoration (A) and the other decoration (B) have distinct colors at room temperature and the same color at a temperature between 100°C and 250°C, preferably between 150°C and 200°C.
5. Method of manufacturing a coated cooking element (1) according to any one of the preceding claims, characterized in that said metal substrate Tl (2) is an aluminum, stainless steel or multi-layer metal substrate.
6. Method for manufacturing a coated cooking element (1) according to any one of the preceding claims, characterized in that the surface of the face (2a) of the metal substrate (2) has undergone a surface treatment, said surface treatment being a chemical attack, brushing, hydration, sandblasting, shot blasting, a physicochemical treatment of the plasma or corona or laser type, a chemical activation or a combination of these different techniques.
7. Method for manufacturing a coated cooking element (1) according to any one of the preceding claims, characterized in that the semi-crystalline or amorphous thermoplastic polymer(s) of the layer (3a) are chosen from: polytetrafluoroethylene (PTFE), copolymers of tetrafluoroethylene and perfluoropropylvinylether (PFA), copolymers of tetrafluoroethylene and hexafluoropropene (FEP), polyvinylidene fluoride (PVDF), copolymers of tetrafluoroethylene and polymethylvinylether (MVA), terpolymers of tetrafluoroethylene, polymethylvinylether and fluoroalkylvinylether (TFE / PMVE / FAVE), ethylene tetrafluoroethylene (ETFE), and mixtures thereof, polyarylether ketones (PAEK), including polyether ketone (PEK), polyether ether ketone (PEEK), polyether ketone ketone (PEKK), polyether ether ketone ketone (PEEKK), polyether ketone ether ketone ketone (PEKEKK), preferably polyether ether ketone (PEEK), polyamideimide (PAI),polyimide (PI), polyetherimide (PEI), polybenzymidazole (PBI), poly(phenylene oxide) (PPO), poly(arylethersulfone) polymers (PAES) including polyethersulfone (PES), polyphenylene ether sulfone (PPSU), poly(arylene sulfides) (PAS) including polyphenylene sulfide (PPS), liquid crystal polymers, polyphthalamide (PPA), and mixtures thereof., 8. Method for manufacturing a coated cooking element (1) according to any one of the preceding claims, characterized in that the face (3a) of the film (3) coming into contact with the face (2a) of the metal substrate during step (iv) has undergone a mechanical or chemical surface treatment.
9. Method for manufacturing a coated cooking element (1) according to any one of the preceding claims, characterized in that the polymer(s) of the other layer (3b) forming the cooking face (4) are chosen from: polytetrafluoroethylene (PTFE), copolymers of tetrafluoroethylene and perfluoropropylvinylether (PFA), copolymers of tetrafluoroethylene and hexafluoropropene (FEP), polyvinylidene fluoride (PVDF), copolymers of tetrafluoroethylene and polymethylvinylether (MVA), terpolymers of tetrafluoroethylene, polymethylvinylether and fluoroalkylvinylether (TFE / PMVE / FAVE), ethylene tetrafluoroethylene (ETFE), and mixtures thereof;preferably PTFE, polyarylether ketones (PAEK), including polyether ketone (PEK), polyether ether ketone (PEEK), polyether ketone ketone (PEKK), polyether ether ketone ketone (PEEKK), polyether ketone ether ketone ketone (PEKEKK), preferably polyether ether ketone (PEEK), polyamideimide (PAI), polyimide (PI), polyetherimide (PEI), polybenzymidazole (PBI), poly(phenylene oxide) (PPO), poly(arylethersulfone) polymers (PAES) including polyethersulfone (PES), polyphenylene ether sulfone (PPSU), poly(arylene sulfides) (PAS) including polyphenylene sulfide (PPS), liquid crystal polymers, polyphthalamide (PPA), silicone resins, and mixtures thereof, preferably mixtures of PTFE and PEEK.; 10. Method for manufacturing a coated cooking element (1) according to any one of the preceding claims, characterized in that the thickness of the layer (3a) and the thickness of the other layer (3b) are each between 5 μm and 500 μm, preferably between 25 μm and 150 μm.
11. Method for manufacturing a coated cooking element (1) according to any one of the preceding claims, characterized in that the film (3) further comprises at least one intermediate layer (3c) positioned between the layer (3a) and the other layer (3b), said intermediate layer (3c) comprising one or more polymers chosen from: - polytetrafluoroethylene (PTFE), copolymers of tetrafluoroethylene and perfluoropropylvinylether (PFA), copolymers of tetrafluoroethylene and hexafluoropropene (FEP), polyvinylidene fluoride (PVDF), copolymers of tetrafluoroethylene and polymethylvinylether (MVA), terpolymers of tetrafluoroethylene, polymethylvinylether and fluoroalkylvinylether (TFE / PMVE / FAVE), ethylene tetrafluoroethylene (ETFE), and mixtures thereof; preferably copolymers of tetrafluoroethylene and perfluoropropylvinylether (PFA) and PTFE; preferably PTFE, - polyarylether ketones (PAEK), including polyether ketone (PEK), polyether ether ketone (PEEK), polyether ketone ketone (PEKK), polyether ether ketone ketone (PEEKK), polyether ketone ether ketone ketone (PEKEKK), preferably polyether ether ketone (PEEK), - polyamideimide (PAI), polyimide (PI), polyetherimide (PEI), polybenzymidazole (PBI), - poly(phenylene oxide) (PPO), poly(arylethersulfone) polymers (PAES) including polyethersulfone (PES), polyphenylene ether sulfone (PPSU), poly(arylene sulfides) (PAS) including polyphenylene sulfide (PPS), liquid crystal polymers, - polyphthalamide (PPA), - silicone resins, - and their mixtures, preferably mixtures of polyarylether ketones (PAEK) and PTFE, preferably mixtures of PEEK and PTFE, PTFE being particularly preferred.
12. Method for manufacturing a coated cooking element (1) according to claim 11 characterized in that the decoration (A) and where appropriate the other decoration (B) are positioned between the layer (3a) and an intermediate layer (3c), or between two intermediate layers (3c), or between an intermediate layer (3c) and the other layer (3b).
13. Method for shaping a coated cooking element (1) according to any one of the preceding claims comprising a step (E1) of stamping the coated cooking element (1) obtained at the end of step (iv).
14. Method of shaping according to claim 13 a coated cooking element (1) further comprising a step (E2) of stretching the coated cooking element (1) obtained at the end of step (E1).
15. Method of shaping according to claim 13 a coated cooking element (1), said coated cooking element (1) having a bottom surrounded by a side wall and being such that the decoration (A) and where appropriate the other decoration (B) are arranged on said bottom.
16. Coated cooking element (1) obtainable according to any one of claims 1 to 15.