Cooking element coated with textured polymer film

Abstract

The invention relates to a coated cooking element (1) for a cooking appliance or an electric cooking appliance, comprising a metal substrate (2) coated on at least one face (2a) by a film (3) forming a cooking face (4), the film (3) comprising a layer (3a) arranged on the side opposite the cooking face (4), the layer (3a) comprising one or more semi-crystalline or amorphous thermoplastic polymers, the film (3) is assembled together with the metal substrate (2), the layer (3a) is in contact with the face (2a) of the metal substrate (2), and such that the cooking face (4) has a structure (5) constituting a projection characterized by a maximum profile height Rt of between 10 [mu] m and 500 [mu] m, preferably between 20 [mu] m and 100 [mu] m, measured according to the standard DIN 4768E on January 1, 19990. The invention also relates to a method for producing a coated cooking element, in which the cooking surface (4) has a structure (5), and to a cooking appliance or an electric cooking appliance comprising such a coated cooking element (1).

Description

Field of the Invention

[0001] The present invention relates to the field of cooking elements coated with a non-stick film having a surface structure, and to a method for obtaining such cooking elements.

[0002] The present invention also relates to cooking utensils and electric cooking appliances comprising such cooking elements. Background Art

[0003] In the industry of cooking utensils comprising a non-stick cooking surface, the performance of the non-stick coating and the development of methods for obtaining such a coating are important concerns.

[0004] Hitherto, in order to form a kitchen utensil, a metal substrate is first shaped, and then, on the inner surface of the kitchen utensil, a fluororesin having excellent heat resistance, such as polytetrafluoroethylene (PTFE), is coated by a liquid spraying method or a powder spraying method. An alternative consists in coating the substrate and then shaping the thus-coated substrate.

[0005] The liquid spraying method has a number of drawbacks. When the metal substrate has a curved shape, it is difficult to obtain a coating of uniform thickness. In addition, the liquid spraying method involves the use of solvents or volatile organic compounds, which evaporate in the method and must be recovered and recycled. From an environmental point of view, a method without solvents and without volatile organic compounds is preferred. In addition, the thickness of the coating is limited. If the coating thickness is too large, cracks may occur.

[0006] The powder coating method also has drawbacks. The obtained coating has defects of the needle type, which results in a reduction of the non-stick properties.

[0007] The coatings obtained according to these two methods may have a significant surface roughness, which can cause cleaning problems, and certain cooking residues may remain on the surface of the coating even after several washings. In addition, the metal substrate on which the coating is deposited usually also has a significant roughness in order to promote the adhesion of the coating. Thus, scratches affecting the coating in the protruding areas of the cooking surface may expose the metal substrate, which corresponds to a significant deterioration of the coating.

[0008] To overcome the above drawbacks, the prior art describes metal substrates coated by laminating a fluorinated film.

[0009] Patent application KR20150030719 describes a kitchen utensil comprising a body including a metal substrate on which a fluorinated resin film is laminated. A method for obtaining a kitchen utensil is also described. In Example 1, a multi-layer PTFE film is used without any information on the nature of the layers.

[0010] Application KR20160099388 describes a method of obtaining a metal substrate coated with a fluorinated film (a primer layer without organic compounds or binders). The fluorinated film is a multi-layer film obtained by continuously depositing an aqueous dispersion of the components (fluorinated resin and optional inorganic fillers) of a dried and sintered layer on a carrier. The multi-layer film is then removed from its carrier and positioned on the metal substrate before assembly. The fluorinated film layer in contact with the metal consists of FEP, PFA, TFM, MFA (or mixtures thereof), which have good flow properties and thus enable good adhesion. The metal substrate / fluorinated film assembly is prepared by hot pressing, in a static press or even between rollers (roll-to-roll method).

[0011] The non-stick cooking surface obtained from the polymer film enables the production of products with a high coating thickness, thus ensuring increased durability of the non-stick effect.

[0012] In addition, these surfaces have extremely smooth surfaces with few defects, enhancing their non-stick properties.

[0013] However, due to the very smooth surface of such cooking utensils, particularly obvious defects will appear over time. In fact, since the polymer material has relatively weak mechanical properties, especially when hot, using utensils such as spatulas will produce scratches, thus reducing the visual appearance of the surface. These scratches are more visible even if they are not very deep when the cooking surface is smooth.

[0014] In addition, the very smooth surface of such cooking utensils contributes to the propagation of scratches. Moreover, due to the very smooth and shiny surface of such cooking utensils, possible surface defects of the film polymer or defects occurring during the manufacturing process of the cooking utensils are particularly visible, which impairs the aesthetic appearance of the cooking utensils. Summary of the Invention

[0015] From an industrial perspective, there is still a need to develop cooking elements comprising a metal substrate coated with a polymer film that forms a cooking surface, which can delay the appearance of visible defects, such as scratches, on the cooking surface and limit the visualization of appearance defects of the cooking surface.

[0016] Therefore, the applicant has developed a cooking element comprising a metal substrate coated with a polymer film, the surface of which is textured, which makes it possible to limit the visualization of appearance defects and defects that occur during the service life of the cooking element, while enabling the non-stick performance to be maintained durably. The characteristics of the cooking element according to the invention facilitate the use of metal utensils to stir food and enable harder foods, such as shellfish, to be cooked more easily.

[0017] The applicant has also developed a method for obtaining such a cooking element, which includes the step of forming a structure constituting a protrusion on the cooking surface of the cooking element.

[0018] Subject matter of the invention

[0019] The inventors have found that by generating a structure constituting a protrusion on the cooking surface (4) of a cooking element (1) including an assembled metal substrate (2) and a film (3), the visual appearance of defects and defects such as scratches that may occur over time can be limited.

[0020] A first object of the present invention relates to a coated cooking element (1) for a cooking utensil or an electric cooking appliance, including a metal substrate (2) coated with a film (3) forming a cooking surface (4) on at least one surface (2a),

[0021] The film (3) includes a layer (3a) arranged on the opposite side of the cooking surface (4), and the layer (3a) includes one or more semi-crystalline or amorphous thermoplastic polymers,

[0022] The film (3) is assembled with the metal substrate (2), and the layer (3a) is in contact with the surface (2a) of the metal substrate (2),

[0023] and the cooking surface (4) has a structure (5) constituting a protrusion, and the protrusion is characterized in that the maximum profile height R measured according to the standard DIN 4768E of January 1, 1990 t is between 10 μm and 500 μm, preferably between 20 μm and 100 μm.

[0024] The present invention also relates to a method for manufacturing a coated cooking element (1) for a cooking utensil or an electric cooking appliance, the cooking element including a cooking surface (4) having a structure (5) constituting a protrusion, and the protrusion is characterized in that the maximum profile height R measured according to the standard DIN 4768E of January 1, 1990 t is between 10 and 500 μm, preferably between 20 and 100 μm,

[0025] The method includes the following consecutive steps i. to v.:

[0026] i. Provide a metal substrate (2),

[0027] ii. Optionally, pretreat the surface (2a) of the metal substrate (2) intended to be coated,

[0028] iii. Provide a film (3) forming the cooking surface (4), and the film includes a layer (3a) containing one or more semi-crystalline or amorphous thermoplastic polymers,

[0029] iv. Position the layer (3a) of the membrane (3) such that the layer (3a) faces the face (2a) of the metal substrate (2),

[0030] v. Perform the assembly of the metal substrate (2) and the membrane (3) by thermocompression,

[0031] The method further includes step vi. of forming the structure (5), and steps v. and vi. can be simultaneous or consecutive.

[0032] The present invention also relates to a cooking utensil (100) comprising a coated cooking element (1) obtained according to the present invention or by the method according to the present invention, and an electric cooking appliance (200) comprising a coated cooking element (1) and a heat source (210) configured to heat the coated cooking element (1), characterized in that the coated cooking element (1) is obtained according to the present invention or by the method according to the present invention.

[0033] Other aspects of the present invention are described in the claims below.

[0034] Definitions

[0035] The term "membrane" within the meaning of the present invention should be understood as a component consisting of one or more overlapping layers intended to be assembled with a metal substrate. The term "membrane" also corresponds to the said component once assembled with the metal substrate.

[0036] The term "layer" within the meaning of the present invention should be understood as a continuous layer. A continuous layer (or also called a monolithic layer) is a single monolith that forms a total solid that completely covers the flat surface on which it is placed or will be placed.

[0037] The term "thermocompression" within the meaning of the present invention should be understood as a method for assembling a preheated metal substrate (2) and a membrane (3) between a lower tool and an upper tool.

[0038] Within the meaning of the present invention, the term "aluminum alloy" should be understood as aluminum alloys of series 1000, 2000, 3000, 4000, 5000, 6000, 7000 and 8000.

[0039] The term "maximum profile height R measured according to the standard DIN 4768E of January 1, 1990 t " is understood to mean the distance between the line of the protrusion corresponding to the highest height and the line of the depression corresponding to the deepest depth in the measurement interval (reference section) of the filtered profile, according to the standard DIN 4768E of January 1, 1990.

[0040] The surface topography can be studied, in particular using a profilometer with a probe equipped with a stylus having a diamond tip, or equipped with an optical metrology instrument of type

[0041] The expression "cooking utensil" should be understood within the meaning of the present invention as an object for cooking. To this end, it is heated in order to cook or reheat food carried by or contained in a cooking element.

[0042] The expression "object intended to be heated in order to cook or reheat food carried by or contained in a cooking element" should be understood within the meaning of the present invention as an object that will be heated by an external heating system such as a cooking hob; such an object may in particular be a frying pan, a sauce pan, a wok, a sauté pan or a grill, and is capable of transferring the heat provided by this external heating system to the material or food in contact with said object.

[0043] The expression "electric cooking appliance" should be understood within the meaning of the present invention as an object intended for cooking. To this end, it is designed to generate heat.

[0044] The expression "object designed to generate heat" should be understood within the meaning of the present invention as a heating object having its own heating system. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 A cross-sectional view of an exemplary embodiment of a coated cooking element (1) including a film (3) and a metal substrate (2) before being assembled according to the method of the present invention is shown.

[0046] Figure 2 A cross-sectional view of an exemplary embodiment of a coated cooking element (1) according to the method of the present invention is shown, the cooking element including a film (3) and a metal substrate (2).

[0047] Figure 3 A schematic cross-sectional view of a coated cooking element (1) is shown, the cooking element including a metal substrate (2) coated with a film (3) forming a cooking surface (4), the cooking surface (4) having a periodic structure (5) of steps Ar.

[0048] Figure 4 A cross-sectional view of an exemplary embodiment of a coated cooking element (1) including a film (3) and a metal substrate (2) before being assembled according to the method of the present invention is shown, the method including a step of assembling the film (3) and the metal substrate (2) by pressing between a lower tool (12A) and an upper tool (12B) of a press such that a plane of the upper tool (12B) in contact with the cooking surface (4) has a texture (6).

[0049] Figure 5 Shows a cross-sectional view of an exemplary embodiment of a coated cooking element (1) including a film (3) and a metal substrate (2) before assembly according to the method of the present invention, said method comprising the step of assembling said film (3) and said metal substrate (2) by pressing between a lower tool (12A) and an upper tool (12B) of a press, and a texturing spacer (7) is positioned facing the cooking surface (4) during assembly.

[0050] Figure 6 Shows a coated cooking element (1) according to the present invention forming a cooking container.

[0051] Figure 7 Shows a cooking utensil (100) including a coated cooking element (1) according to Figure 6 of.

[0052] Figure 8 Shows an electric cooking appliance (200) including a coated cooking element (1) according to Figure 6 of. Detailed description

[0053] The inventors have developed a coated cooking element (1) for a cooking utensil or an electric cooking appliance to meet the said needs, and a method for obtaining such a coated cooking element (1).

[0054] Cooking element

[0055] The present invention also relates to a coated cooking element (1) for a cooking utensil or an electric cooking appliance, comprising a metal substrate (2) coated on at least one face (2a) with a film (3) forming a cooking surface (4),

[0056] said film (3) comprising a layer (3a) arranged on the opposite side of the cooking surface (4), said layer (3a) comprising one or more semi-crystalline or amorphous thermoplastic polymers,

[0057] said film (3) is assembled with said metal substrate (2), and said layer (3a) is in contact with the face (2a) of said metal substrate (2),

[0058] and such that said cooking surface (4) has a structure (5) constituting a protrusion, the protrusion being characterized in that the maximum profile height R measured according to the standard DIN 4768E of January 1, 1990 t is between 10 μm and 500 μm, preferably between 20 μm and 100 μm.

[0059] Metal substrate (2)

[0060] The metal substrate (2) that can be used in the present invention may advantageously comprise a substrate made of aluminum, stainless steel, cast iron or cast aluminum, titanium or copper.

[0061] Within the meaning of the present invention, aluminum should be understood as a metal consisting of 100% aluminum or an aluminum alloy.

[0062] Advantageously, the metal substrate (2) can be an aluminum or stainless steel substrate, or a multi-layer metal substrate, in particular a two-layer, three-layer or four-layer substrate, which multi-layers can be obtained, for example, by co-lamination, by thermal diffusion under load (solid-state bonding) or by bonding through thermal or cold shock.

[0063] Preferably, the metal substrate (2) comprises alternating layers of metal and / or metal alloy.

[0064] According to one embodiment, the metal substrate (2) is a substrate made of an aluminum or stainless steel alloy, or a multi-layer metal substrate whose face (2a) is an aluminum or stainless steel alloy.

[0065] Preferably, the metal substrate (2) is an aluminum substrate.

[0066] Advantageously, the thickness of the metal substrate (2) is between 0.5 mm and 10 mm.

[0067] Advantageously, the face (2a) of the metal substrate (2) has undergone a surface treatment before being assembled with the film (3) to improve the adhesion of the said film to the said substrate.

[0068] According to one embodiment, the surface of the face (2a) of the metal substrate (2) has undergone a surface treatment, which surface treatment is chemical etching, brushing, hydration, sandblasting, shot peening, physical-chemical plasma, corona or laser treatment, chemical activation or a combination of these different techniques.

[0069] Advantageously, the arithmetic mean roughness Ra of the surface of the face (2a) of the metal substrate (2) is greater than or equal to 1 μm.

[0070] The arithmetic mean roughness Ra is measured by a roughness meter according to the standard ISO 4287. Ra represents the arithmetic mean of the deviations from the mean value. The surface topography can be studied, in particular using a profilometer with a probe equipped with a fine pen with a diamond tip, or equipped with an optical metrology instrument of type, where a confocal color sensor enables non-contact measurement. Studying the surface topography data can determine the arithmetic mean roughness Ra.

[0071] Advantageously, the cooking element (1) does not include an intermediate layer of metal oxide between the metal substrate (2) and the following film (3).

[0072] Film (3)

[0073] The membrane (3) comprises a layer (3a) containing one or more semi-crystalline or amorphous polymers, and the layer (3a) is intended to be placed in contact with the face (2a) of the metal substrate (2).

[0074] According to one embodiment, one or more semi-crystalline or amorphous thermoplastic polymers of the layer (3a) are selected from:

[0075] - polytetrafluoroethylene (PTFE), copolymer of tetrafluoroethylene and perfluoropropyl vinyl ether (PFA), copolymer of tetrafluoroethylene and hexafluoropropylene (FEP), polyvinylidene fluoride (PVDF), copolymer of tetrafluoroethylene and poly(methyl vinyl ether) (MVA), terpolymer of tetrafluoroethylene, poly(methyl vinyl ether) and fluoroalkyl vinyl ether (TFE / PMVE / FAVE), ethylene tetrafluoroethylene (ETFE) and mixtures thereof,

[0076] - polyaryletherketone (PAEK), including polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetheretherketoneketone (PEEKK), polyetherketoneetherketoneketone (PEKEKK), preferably polyetheretherketone (PEEK),

[0077] - polyamideimide (PAI), polyimide (PI), polyetherimide (PEI), polybenzimidazole (PBI),

[0078] - and mixtures thereof.

[0079] The melting point of PTFE and semi-crystalline thermoplastic polymers and the glass transition temperature (Tg) of amorphous thermoplastic polymers can be determined by thermal analysis methods such as differential thermal analysis (DTA or DSC for differential scanning calorimetry) or even by dynamic mechanical analysis (DMA).

[0080] The membrane (3) can be constituted by a single layer (3a) that also forms the cooking surface (4).

[0081] According to another configuration, the membrane (3) further comprises an additional layer located above the layer (3a) as described above. In this case, the membrane (3) thus further comprises another layer (3b) that forms the cooking surface (4), and the another layer (3b) comprises one or more polymers selected from the following:

[0082] - Polytetrafluoroethylene (PTFE), copolymers of tetrafluoroethylene and perfluoropropyl vinyl ether (PFA), copolymers of tetrafluoroethylene and hexafluoropropylene (FEP), polyvinylidene fluoride (PVDF), copolymers of tetrafluoroethylene and poly(methyl vinyl ether) (MVA), terpolymers of tetrafluoroethylene, poly(methyl vinyl ether) and fluoroalkyl vinyl ether (TFE / PMVE / FAVE), ethylene tetrafluoroethylene (ETFE) and mixtures thereof; preferably PTFE;

[0083] - Polyaryletherketone (PAEK), including polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetheretherketoneketone (PEEKK), polyetherketoneetherketoneketone (PEKEKK), preferably polyetheretherketone (PEEK),

[0084] - Polyamideimide (PAI), polyimide (PI), polyetherimide (PEI), polybenzimidazole (PBI),

[0085] - And mixtures thereof, preferably a mixture of PTFE and PEEK.

[0086] According to one embodiment, the membrane (3) further comprises at least one intermediate layer (3c) located between the layer (3a) and another layer (3b), and the intermediate layer (3c) comprises one or more polymers selected from the following:

[0087] - Polytetrafluoroethylene (PTFE), copolymers of tetrafluoroethylene and perfluoropropyl vinyl ether (PFA), copolymers of tetrafluoroethylene and hexafluoropropylene (FEP), polyvinylidene fluoride (PVDF), copolymers of tetrafluoroethylene and poly(methyl vinyl ether) (MVA), terpolymers of tetrafluoroethylene, poly(methyl vinyl ether) and fluoroalkyl vinyl ether (TFE / PMVE / FAVE), ethylene tetrafluoroethylene (ETFE) and mixtures thereof; preferably a copolymer of tetrafluoroethylene and perfluoropropyl vinyl ether (PFA) and PTFE; preferably PTFE,

[0088] - Polyaryletherketone (PAEK), including polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetheretherketoneketone (PEEKK), polyetherketoneetherketoneketone (PEKEKK), preferably polyetheretherketone (PEEK),

[0089] - Polyamideimide (PAI), polyimide (PI), polyetherimide (PEI), polybenzimidazole (PBI),

[0090] - And mixtures thereof, preferably a mixture of polyaryletherketone (PAEK) and PTFE, preferably a mixture of PEEK and PTFE;

[0091] PTFE is particularly preferred.

[0092] The membrane (3) may further comprise at least one filler and / or at least one reinforcing material.

[0093] As fillers that can be used in the context of the present invention, mention may be made in particular of metal oxides, metal carbides, metal oxynitrides, metal nitrides and mixtures thereof.

[0094] These fillers may be present in one or more layers of the membrane (3) or in each layer of the membrane (3).

[0095] Reinforcing materials that can be used in the present invention include fibrous mineral or metallic reinforcing materials, metal meshes, glass fiber materials or fabrics. The reinforcing material may also consist of a non-fluorinated polymer of the polyaryletherketone (PAEK) type having high thermomechanical properties, such as polyetheretherketone (PEEK) or polyamide-imide (PAI). The reinforcing material may be in the form of a layer of the membrane (3) located between the layer (3a) and another layer (3b) forming the cooking surface.

[0096] In order to improve the adhesion of the membrane (3) to the metal substrate (2), the layer (3a) of the membrane (3) in contact with the face (2a) of the metal substrate (2) during step (v) may have undergone a mechanical or chemical surface treatment. The surface treatment may be chemical etching, brushing, hydration, sandblasting, shot peening, physicochemical plasma, corona or laser treatment, chemical activation or a combination of these different techniques.

[0097] According to another embodiment, the thickness of the membrane (3) is between 10 μm and 500 μm, preferably between 15 μm and 250 μm, and particularly preferably between 25 μm and 150 μm.

[0098] The thickness of one or more layers of the membrane (3) is measured at 20 random points on the cross-section of the membrane. The average thickness of the membrane (3) is obtained by taking the average of these 20 measurements.

[0099] The total thickness of the membrane (3) of the coated cooking element (1) according to the present invention, in other words, measured on the cooking element once the cooking element has been coated with the membrane (3), is between 10 μm and 500 μm, preferably between 15 μm and 250 μm, and particularly preferably between 25 μm and 150 μm.

[0100] The thickness of the membrane (3) of the coated cooking element (1) according to the present invention is measured at 20 random points on the cross-section of the coated substrate. The average thickness of the membrane (3) is obtained by taking the average of these 20 measurements.

[0101] Before assembly with the metal substrate (2), the film (3) can be obtained by depositing a first layer on a carrier, then optionally by successive deposition of other layers, and then by peeling off the film so as to separate it from the carrier. The layers of the film (3) can also be assembled by any other assembly method, such as lamination.

[0102] Advantageously, the film (3) of the coated cooking element (1) covers the entire face (2a) of the metal substrate (2).

[0103] In Figure 1 、 Figure 2 、 Figure 4 and Figure 5 In the exemplary embodiments shown, the film (3) comprises three layers: a layer (3a), another layer (3b) and an intermediate layer (3c).

[0104] Structure (5)

[0105] The cooking surface (4) of the cooking element (1) as described below has a structure (5) forming a protrusion, the protrusion being characterized by a maximum profile height R measured according to the standard DIN 4768E of 1 January 1990 t between 10 and 500 μm, preferably between 20 and 100 μm.

[0106] Generating the structure (5) on the cooking surface (4) enables the surface to be made less smooth and less shiny, and thus the visualization of defects, whether they are appearance defects or scratches that may occur during use, can be limited.

[0107] By generating protrusions with a maximum profile height R t greater than 10 μm, preferably greater than 20 μm, these defects and scratches can be visually masked.

[0108] However, the maximum profile height R t must remain limited so as not to degrade the performance as a cooking surface and thus avoid preferential contamination areas, such as in the depressions presented by the protrusions. Thus, it is less than 500 μm, preferably less than 100 μm.

[0109] Due to the presence of the structure (5) on the cooking surface (4), the film (3) of the coated cooking element (1) has a non-constant thickness. It has a non-zero minimum thickness or residual thickness denoted as E r such that the face (2a) of the metal substrate (2) is completely covered by the film (3).

[0110] This residual thickness E r maintains non-stickiness even in the case of scratching and progressive wear in the protrusion areas of the film (3).

[0111] According to one embodiment, the residual thickness E of the film (3) r is greater than or equal to 10 μm, and preferably greater than or equal to 20 μm.

[0112] The residual thickness E of the film (3) is measured on a part of the coated cooking element (1) r .

[0113] The maximum profile height R of the structure (5) t can be between 20% and 180% of the thickness of the film (3), preferably between 50% and 150%, and particularly preferably between 80% and 120%.

[0114] The thickness of the film (3) of the coated cooking element (1) is measured according to the above scheme.

[0115] The protrusions of the structure (5) include a pattern formed by a horizontal local change in the surface of the cooking surface (4).

[0116] According to one embodiment, the protrusions of the structure (5) include a periodic pattern or consist of a periodic pattern.

[0117] In this case, the protrusions of the structure (5) can include the same basic pattern repeated at regular intervals, or consist of the same basic pattern repeated at regular intervals.

[0118] Advantageously, the protrusions of the structure (5) are formed by patterns with a step Ar that are spaced apart from each other, where the distance between two protrusion patterns is greater than 100 μm, preferably greater than 150 μm, and more preferably greater than 200 μm.

[0119] Advantageously, the protrusions of the structure (5) do not include a periodic pattern, or are formed by patterns that are far apart from each other, with a step Ar corresponding to the distance between two protrusion patterns that is greater than 100 μm, preferably greater than 150 μm, and more preferably greater than 200 μm.

[0120] Figure 3 A schematic cross-sectional view of a coated cooking element (1) is shown, which includes a metal substrate (2) coated with a film (3) forming a cooking surface (4), and the cooking surface (4) has a periodic structure (5) with a maximum profile height R t and a periodic profile with a step Ar. The surface (2a) of the metal substrate (2) is shown to have surface roughness.

[0121] As Figure 3 shown, the point with the lowest height of the film (3) rises to a height higher than the height of the point with the highest height of the metal substrate (2). Thus, as Figure 3It can be clearly seen that the film (3) forms a continuous substrate (3d) above the metal substrate (2), and the structure (5) is formed above the continuous substrate (3d). In Figure 3 it is denoted as E r The minimum thickness or residual thickness corresponds to the thickness of the continuous substrate (3d). The residual thickness E of the film (3) r is less than the initial thickness E corresponding to the thickness of the above-mentioned film (3) f .

[0122] Therefore, the notch affecting the film (3) will first involve the structure (5) and then the continuous substrate (3d). The notch will require a greater depth to reach the metal substrate (2).

[0123] According to one embodiment, the protrusions of the structure (5) include or consist of an aperiodic pattern.

[0124] In an alternative, the protrusions of the structure (5) may include a periodic pattern and / or an aperiodic pattern.

[0125] The structure (5) produces an unevenness in the thickness of the film (3), which results in a change in scratch resistance on the surface, which can help prevent the formation of long scratches.

[0126] The structure (5) can be present on all or part of the cooking surface (4).

[0127] Manufacturing method

[0128] The invention also relates to a method for manufacturing a coated cooking element (1) for a cooking utensil or an electric cooking appliance, the cooking element comprising a cooking surface (4) having a structure (5) constituting a protrusion, the protrusion being characterized in that the maximum profile height R measured according to the standard DIN 4768E of January 1, 1990 t is between 10 and 500 μm, preferably between 20 and 100 μm,

[0129] The method comprises the following successive steps i. to v.:

[0130] i. Providing a metal substrate (2),

[0131] ii. Optionally, pretreating the surface (2a) of the metal substrate (2) intended to be coated,

[0132] iii. Providing a film (3) forming the cooking surface (4), the film comprising a layer (3a) containing one or more semi-crystalline or amorphous thermoplastic polymers,

[0133] iv. Position the layer (3a) of the membrane (3) such that the layer (3a) faces the face (2a) of the metal substrate (2),

[0134] v. Perform the assembly of the metal substrate (2) and the membrane (3) by thermocompression,

[0135] The method further comprises step vi. of forming the structure (5), and steps v. and vi. can be simultaneous or consecutive.

[0136] The structure (5) of the cooking element (1), the metal substrate (2), the membrane (3) and the cooking surface (4) is as described above.

[0137] Assembly step v)

[0138] Step v. of assembling the metal substrate (2) and the membrane (3) by thermocompression.

[0139] The term "thermocompression" refers to any method that can be used to perform the assembly of a metal substrate and a polymer membrane, by applying a high temperature during assembly, typically higher than the melting point of the semi-crystalline thermoplastic polymer and the lowest temperature of the glass transition temperature (Tg) of the amorphous thermoplastic polymer of the layer (3a), and at a high pressure, typically greater than several MPa, for a sufficient time, ranging from one second to several minutes.

[0140] The assembly can be prepared by thermocompression, in a static press or even between rollers (roll-to-roll method). The pressure applied by thermocompression is typically several MPa. The implementation temperature is usually limited by the degradation temperature of the polymer membrane to be assembled.

[0141] Assembly can be carried out by thermo-shock bonding. In this case, the pressure applied is greater than that in the thermocompression method, about several hundred MPa, and the shock bonding time is very short, typically about several seconds, which allows the use of a higher temperature.

[0142] Assembly by solid-state bonding can also be mentioned, without limitation.

[0143] Advantageously, at the end of step v. of the assembly of the membrane (3) and the metal substrate (2), in other words, when the assembly of the membrane (3) and the metal substrate (2) is no longer under pressure, the temperature of the membrane (3) is lower than the lowest temperature among the melting point of the semi-crystalline thermoplastic polymer and the glass transition temperature (Tg) of the amorphous thermoplastic polymer of the layer (3a).

[0144] After assembly, the metal substrate (2) coated with the membrane (3) is allowed to cool to ambient temperature to obtain the maximum adhesion between the metal substrate (2) and the membrane (3).

[0145] Step vi) of forming structure (5)

[0146] Step v) of assembling the metal substrate (2) and the film (3) and step vi) of producing the structure (5) can be simultaneous or consecutive.

[0147] According to a variant of the method, during the hot pressing step v) or during a cold pressing step following the hot pressing, the structure (5) can be formed on the cooking surface (4):

[0148] - either by the texture (6) of the surface of the pressing tool in contact with the cooking surface (4).

[0149] The texture of the tool can be produced by laser or chemical etching, electrical discharge machining or mechanical etching;

[0150] - or by a textured spacer (7) located between the face of the pressing tool and the film (3).

[0151] The spacer can be a textured metallic material, a metallic fabric, a welded metal mesh, a fiberglass woven fabric or even a carbon fiber woven fabric.

[0152] According to one embodiment, steps v. and vi. are simultaneous and are carried out using a hydraulic press or a mechanical press which includes a lower tool (12A) and an upper tool (12B), between which the metal substrate (2) and the film (3) are assembled, and such that the plane of the surface of the tool in contact with the cooking surface (4) has a texture (6) which can impart the said structure (5) to the said cooking surface (4).

[0153] Figure 4 An embodiment is shown according to which the upper tool (12B) has the said texture (6).

[0154] According to another embodiment, steps v. and vi. are simultaneous and are carried out using a hydraulic press or a mechanical press which includes a lower tool (12A) and an upper tool (12B), between which the metal substrate (2) and the film (3) are assembled,

[0155] and further includes step iv(a). of positioning a textured spacer (7) between step iv. and step v., such that the textured spacer faces the cooking surface (4) of the film (3) and is able to impart the said structure (5) to the said cooking surface (4) during the assembly step v.

[0156] Figure 5 Such an embodiment is shown.

[0157] According to another embodiment, steps v. and vi. are consecutive, and step vi. is performed using a hydraulic press or a mechanical press that includes a lower tool (12A) and an upper tool (12B), and the metal substrate (2) and the film (3) assembled during step v. are cold pressed between the lower tool and the upper tool, and the surface of the tool that contacts the cooking surface (4) during step vi. has a texture (6) that can impart the structure (5) to the cooking surface (4).

[0158] According to another embodiment, steps v. and vi. are consecutive, and step vi. is a step of cold pressing the metal substrate (2) and the film (3) assembled during step v., wherein a textured spacer (7) is positioned facing the cooking surface (4) and is capable of imparting the structure (5) to the cooking surface (4) during step vi).

[0159] During step vi., the film (3) flows into the pattern of the textured spacer (7) or into the recesses of the texture (6) on the surface of the pressing tool, thereby enabling the structure (5) to be produced.

[0160] According to the method implemented in step vi., according to the desired maximum profile height R t and the thickness of the film (3), deformation of the film (3) can be produced with or without deformation of the metal substrate (2).

[0161] Then, the metal substrate (2) coated with the film (3) can be shaped by stamping and then stretching if applicable, and its cooking surface (4) has the structure (5).

[0162] According to another variant of the method, the structure (5) of the cooking surface (4) can also be produced by mechanically grinding the surface of the film (3).

[0163] The structure (5) can be manufactured as follows:

[0164] - Directly after the film (3) and the metal substrate (2) are assembled.

[0165] - Or after the forming step of the cooking element (1).

[0166] According to one embodiment, steps v. and vi. are consecutive, and step vi. is a step of mechanically treating the cooking surface (4) of the metal substrate (2) and the film (3) assembled during step v).

[0167] The mechanical treatment can be brushing, emery grinding, sandblasting, shot peening, micro shot peening, shot peening hardening, or a combination of these techniques.

[0168] An abrasive for the mechanical treatment of a cooking surface (4), the characteristics (properties, shape, dimensions) of which are selected according to the desired structure (5) of the cooking surface (4).

[0169] For example, the element to be textured can be placed on a lathe to generate a structure (5) with a circular pattern.

[0170] Then, the metal substrate (2) coated with the film (3) can be shaped by stamping and then, if applicable, stretching.

[0171] Before shaping, the adhesion of the film (3) to the metal substrate (2) must be good enough to avoid any loss of adhesion during and after the shaping operation.

[0172] The metal substrate (2) coated with the film (3) can be shaped before step vi. of forming the structure (5) by mechanical treatment of the cooking surface (4).

[0173] According to one embodiment, the method thus further comprises, between step v. and step vi. of mechanical treatment, step v(a). of shaping by stamping and then, if applicable, stretching the metal substrate (2) and the film (3) assembled during step v.

[0174] Step vi. of forming the structure (5) is carried out on all or part of the cooking surface (4).

[0175] Figure 6 A coated cooking element (1) according to the invention for forming a cooking container is shown. The film (3) assembled with the metal substrate (2) forms a cooking surface (4) arranged inside the cooking container.

[0176] Cooking appliance

[0177] Another object of the invention relates to a cooking utensil (100) comprising, for example, a coated cooking element (1) as described above or obtained according to a method as described above.

[0178] The coated cooking element (1) according to the method of the invention can form a cooking container in a cooking utensil (100).

[0179] According to Figure 7 the embodiment shown, the cooking utensil (100) comprises a heating surface (8) for placement in contact with an external heat source, the heating surface (8) being opposite to the cooking surface (4) for placement in contact with food during cooking. The cooking utensil (100) is also equipped with a gripping member (9) fixed to the coated cooking element (1).

[0180] According to one embodiment, a cooking utensil (100) includes a coated cooking element (1) having a bottom (10) and side walls (11), and the cooking surface (4) has the structure (5) on the bottom.

[0181] According to a variant of this embodiment, only the bottom (10) has the structure (5).

[0182] According to another variant of this embodiment, the bottom (10) and the side walls (11) have the structure (5).

[0183] The structure (5) preferably extends over the entire bottom (10).

[0184] When the structure (5) is present on the side walls (11), it does not have to extend over the entire side walls (11).

[0185] According to a preferred embodiment, the entire cooking surface (4) of the coated cooking element (1) has the structure (5). Then the coated cooking element (1) is shaped by stamping and, where applicable, stretching, such that the bottom (10) and the side walls (11) have the structure (5).

[0186] According to a preferred embodiment, after stamping and, where applicable, stretching, only the bottom (10) of the cooking element (1) of the cooking utensil (100) has the structure (5).

[0187] The cooking utensil (100) according to the invention is selected from the group consisting of saucepans, frying pans, fondue or raclette pans or griddles, stewpans, woks, fry pans, pancake pans, grills, flat grills, cooking pots, casseroles, containers for cookers or bread machines, cooking molds.

[0188] Electric cooking appliance

[0189] Another object of the invention also relates to an electric cooking appliance (200) which includes a coated cooking element (1) according to the invention and a heat source (210) designed to heat the coated cooking element (1).

[0190] The coated cooking element (1) according to the method of the invention can form a cooking container in the electric cooking appliance (200).

[0191] According to Figure 8Another embodiment as shown, the electric cooking appliance (200) according to the present invention includes a coated cooking element (1) and a heat source (210) designed to heat the coated cooking element (1). The coated cooking element (1) forming the cooking container is arranged in a heating base (230), which heating base includes a heat source (210) composed of a plurality of heating elements (220). A surface (8) abuts against the heating element (220). If desired, the surface (8) can be rigidly connected to the heating element (220).

[0192] According to one embodiment, the electric cooking appliance (200) includes a coated cooking element (1), which coated cooking element includes a bottom (10) and a side wall (11), and such that a cooking surface (4) has the structure (5) on the bottom.

[0193] According to a variant of this embodiment, only the bottom (10) has the structure (5).

[0194] According to another variant of this embodiment, the bottom (10) and the side wall (11) have the structure (5).

[0195] The structure (5) preferably extends over the entire bottom (10).

[0196] When the structure (5) is present on the side wall (11), it does not have to extend over the entire side wall (11).

[0197] The electric cooking appliance (200) may be selected from the group consisting of an electric pancake maker, an electric raclette machine, an electric fondue machine, an electric grill, an electric griddle, an electric cooking appliance, a bread machine.

Claims

1. A coated cooking element (1) for a cooking utensil or an electric cooking appliance, comprising a metal substrate (2) coated on at least one face (2a) with a film (3) forming a cooking face (4). The film (3) comprises a layer (3a) arranged on the opposite side of the cooking face (4), the layer (3a) comprising one or more semi-crystalline or amorphous thermoplastic polymers. The film (3) is assembled with the metal substrate (2), and the layer (3a) is in contact with the face (2a) of the metal substrate (2). and causing the cooking surface (4) to have a structure (5) forming a protrusion, the protrusion being characterized in that the maximum profile height R measured according to the standard DIN 4768E of 1 January 1990 t is between 10 μm and 500 μm, preferably between 20 μm and 100 μm.

2. The coated cooking element (1) according to claim 1. Characterized in that The metal substrate (2) is a substrate made of aluminum, stainless steel or a multi-layer metal substrate.

3. The coated cooking element (1) according to any one of the preceding claims. Characterized in that Before assembling the film (3) with the face (2a) of the metal substrate (2), the face (2a) of the metal substrate (2) has undergone a surface treatment.

4. The coated cooking element (1) according to any one of the preceding claims. Characterized in that The thickness of the film (3) is between 10 μm and 500 μm, preferably between 15 μm and 250 μm, and particularly preferably between 25 μm and 150 μm.

5. The coated cooking element (1) according to any one of the preceding claims. Characterized in that The residual thickness E of the membrane (3) r is greater than or equal to 10 μm, and preferably greater than or equal to 20 μm.

6. The coated cooking element (1) according to any one of the preceding claims. Characterized in that The crystalline or amorphous thermoplastic polymer of the layer (3a) is selected from: - Polytetrafluoroethylene (PTFE), copolymers of tetrafluoroethylene and perfluoropropyl vinyl ether (PFA), copolymers of tetrafluoroethylene and hexafluoropropylene (FEP), polyvinylidene fluoride (PVDF), copolymers of tetrafluoroethylene and poly(methyl vinyl ether) (MVA), terpolymers of tetrafluoroethylene, poly(methyl vinyl ether) and fluoroalkyl vinyl ether (TFE / PMVE / FAVE), ethylene tetrafluoroethylene (ETFE) and mixtures thereof. - Polyaryletherketone (PAEK), including polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetheretherketoneketone (PEEKK), polyetherketoneetherketoneketone (PEKEKK), preferably polyetheretherketone (PEEK). - Polyamideimide (PAI), polyimide (PI), polyetherimide (PEI), polybenzimidazole (PBI). - And mixtures thereof.

7. The coated cooking element (1) according to any one of the preceding claims. Characterized in that The film (3) consists of a single layer (3a) that also forms the cooking face (4).

8. The coated cooking element (1) according to any one of claims 1 to 6. Characterized in that The film (3) further comprises another layer (3b) forming the cooking face (4), the another layer (3b) comprising one or more polymers selected from the following: - Polytetrafluoroethylene (PTFE), copolymers of tetrafluoroethylene and perfluoropropyl vinyl ether (PFA), copolymers of tetrafluoroethylene and hexafluoropropylene (FEP), polyvinylidene fluoride (PVDF), copolymers of tetrafluoroethylene and poly(methyl vinyl ether) (MVA), terpolymers of tetrafluoroethylene, poly(methyl vinyl ether) and fluoroalkyl vinyl ether (TFE / PMVE / FAVE), ethylene tetrafluoroethylene (ETFE) and mixtures thereof; preferably PTFE; - Polyaryletherketone (PAEK), including polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetheretherketoneketone (PEEKK), polyetherketoneetherketoneketone (PEKEKK), preferably polyetheretherketone (PEEK), - Polyamideimide (PAI), polyimide (PI), polyetherimide (PEI), polybenzimidazole (PBI), - And mixtures thereof, preferably a mixture of PTFE and PEEK.

9. The coated cooking element (1) according to claim 8, Characterized in that, The film (3) further comprises at least one intermediate layer (3c) located between the layer (3a) and the other layer (3b), and the intermediate layer (3c) comprises one or more polymers selected from the following: - Polytetrafluoroethylene (PTFE), copolymers of tetrafluoroethylene and perfluoropropyl vinyl ether (PFA), copolymers of tetrafluoroethylene and hexafluoropropylene (FEP), polyvinylidene fluoride (PVDF), copolymers of tetrafluoroethylene and poly(methyl vinyl ether) (MVA), terpolymers of tetrafluoroethylene, poly(methyl vinyl ether) and fluoroalkyl vinyl ether (TFE / PMVE / FAVE), ethylene tetrafluoroethylene (ETFE) and mixtures thereof; preferably a copolymer of tetrafluoroethylene and perfluoropropyl vinyl ether (PFA) and PTFE; preferably PTFE, - Polyaryletherketone (PAEK), including polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetheretherketoneketone (PEEKK), polyetherketoneetherketoneketone (PEKEKK), preferably polyetheretherketone (PEEK), - Polyamideimide (PAI), polyimide (PI), polyetherimide (PEI), polybenzimidazole (PBI), - And mixtures thereof, preferably a mixture of polyaryletherketone (PAEK) and PTFE, preferably a mixture of PEEK and PTFE; PTFE is particularly preferred.

10. The coated cooking element (1) according to any one of the preceding claims, Characterized in that, The structure (5) is present on all or part of the cooking surface (4).

11. A method for manufacturing a coated cooking element (1) for a cooking utensil or an electric cooking appliance, said cooking element comprising a cooking surface (4) having a structure (5) forming protrusions, the protrusions being characterized in that the maximum profile height R measured according to the standard DIN 4768E of 1 January 1990 t is between 10 μm and 500 μm, preferably between 20 μm and 100 μm, The method comprises the following successive steps i. to v.: i. Providing a metal substrate (2), ii. Optionally, pre-treating the surface (2a) of the metal substrate (2) intended to be coated, iii. Providing a film (3) forming the cooking surface (4), the film comprising a layer (3a) containing one or more semi-crystalline or amorphous thermoplastic polymers, iv. Position the layer (3a) of the membrane (3) such that the layer (3a) faces the face (2a) of the metal substrate (2), v. Perform the assembly of the metal substrate (2) and the membrane (3) by hot pressing, The method further includes step vi. of forming the structure (5), and steps v. and vi. can be simultaneous or consecutive.

12. The method according to claim 11, characterized in that, steps v. and vi. are simultaneous and are performed using a hydraulic press or a mechanical press including a lower tool (12A) and an upper tool (12B), with the metal substrate (2) and the membrane (3) assembled between the lower tool and the upper tool, and such that the plane of the surface of the tool in contact with the cooking surface (4) has a texture (6) that can impart the structure (5) to the cooking surface (4).

13. The method according to claim 11, characterized in that, steps v. and vi. are simultaneous and are performed using a hydraulic press or a mechanical press including a lower tool (12A) and an upper tool (12B), with the metal substrate (2) and the membrane (3) assembled between the lower tool and the upper tool, and the method further includes step iv(a). of positioning a textured spacer (7) between step iv. and step v. such that the textured spacer faces the cooking surface (4) of the membrane (3) and can impart the structure (5) to the cooking surface (4) during the assembly step v.

14. The method according to claim 11, characterized in that, steps v. and vi. are consecutive and step vi. is performed using a hydraulic press or a mechanical press, which includes a lower tool (12A) and an upper tool (12B), and cold presses the metal substrate (2) and the membrane (3) assembled during step v. between the lower tool and the upper tool, and such that the plane of the surface of the tool in contact with the cooking surface (4) during step vi. has a texture (6) that can impart the structure (5) to the cooking surface (4).

15. The method according to claim 11, characterized in that, steps v. and vi. are consecutive and step vi. is a step of cold pressing the metal substrate (2) and the membrane (3) assembled during step v., where a textured spacer (7) is positioned facing the cooking surface (4) and can impart the structure (5) to the cooking surface (4) during step vi.

16. The method according to claim 11, characterized in that, steps v. and vi. are consecutive and step vi. is a step of mechanically treating the cooking surface (4) of the metal substrate (2) and the membrane (3) assembled during step v.

17. The method according to claim 16, characterized in that, the mechanical treatment is brushing, emery grinding, sandblasting, shot peening, micro-shot peening, shot peening hardening or a combination of these techniques.

18. The method according to claim 16 or claim 17, characterized in that the method further comprises, between step v. and step vi., step v(a). of stamping and then, where applicable, stretching the metal substrate (2) and the film (3) assembled during step v.

19. The method according to any one of claims 11 to 18, characterized in that step vi. of forming the structure (5) is carried out on all or part of the cooking surface (4).

20. A cooking utensil (100) comprising a coated cooking element (1) obtained according to any one of claims 1 to 10 or according to any one of claims 11 to 19.

21. The cooking utensil (100) according to claim 20, characterized in that the cooking utensil comprises a heating surface (8) configured to be placed in contact with an external heat source, the heating surface (8) being opposite a cooking surface (4) configured to be placed in contact with food during cooking.

22. The cooking utensil according to claim 21, characterized in that the cooking element (1) comprises a bottom and a sidewall, and the cooking surface (4) has the structure (5) on the bottom.

23. The cooking utensil (100) according to any one of claims 20 to 22, selected from the group consisting of saucepans, frying pans, fondue or raclette pans or griddles, stew pans, woks, fry pans, pancake makers, grills, flat grills, cooking pots, casserole dishes, containers for cookers or bread machines, cooking moulds.

24. An electric cooking appliance (200) comprising a coated cooking element (1) and a heat source (210) configured to heat the coated cooking element (1), characterized in that the coated cooking element (1) is a cooking element according to any one of claims 1 to 10 or obtained according to any one of claims 11 to 19.

25. The electric cooking appliance (200) according to claim 24, characterized in that the cooking element (1) comprises a bottom and a sidewall, and the cooking surface (4) has the structure (5) on the bottom.

26. The electric cooking appliance (200) according to claim 24 or 25, selected from the group consisting of electric pancake makers, electric raclette machines, electric fondue machines, electric grills, electric flat grills, electric cooking appliances, bread machines.

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