Cooking elements coated with textured polymer film

Abstract

The present invention relates to a coated cooking element (1) for a cookware or electric cookware, comprising a metal substrate (2) coated on at least one surface (2a) by a film (3) forming a cooking surface (4), wherein the film (3) includes a layer (3a) positioned on the opposite side of the cooking surface (4), the layer (3a) comprises one or more semicrystalline or amorphous thermoplastic polymers, the film (3) is assembled with the metal substrate (2), the layer (3a) is in contact with the surface (2a) of the metal substrate (2), and as a result the cooking surface (4) has a structure (5) that constitutes a projection characterized by a maximum profile height Rt of 10 to 500 μm, preferably 20 to 100 μm, as measured according to the standard DIN 4768E of January 1, 1990.

Description

Technical Field

[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 a cooking element.

[0002] The present invention also relates to culinary items and electric cooking appliances comprising such a cooking element.

Background Art

[0003] Prior Art In the industry of culinary items comprising a non-stick cooking surface, the performance of non-stick coatings and the development of methods for obtaining such coatings are important issues of concern.

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

[0005] The liquid spray coating method has a number of drawbacks. When the metal substrate has a curved shape, it is difficult to obtain a coating of uniform thickness. Furthermore, the liquid spray coating method involves the use of solvents or volatile organic compounds that evaporate during the process and must be recovered and recycled. From an environmental point of view, a method that does not contain solvents and does not contain volatile organic compounds is preferred. Furthermore, the thickness of the coating is limited. If the coating thickness is too large, cracks may appear.

[0006] The powder coating process also has its drawbacks. The resulting coating may have pinhead-type defects, which can lead to a decrease in non-stick properties.

[0007] The coatings obtained through these two processes may have significant surface roughness, which can cause cleaning problems, and some cooking residue may remain on the coating surface even after several washes. Furthermore, the metal substrate on which the coating is deposited also typically has significant roughness to facilitate coating attachment. Therefore, scratches affecting the coating in protruding areas of the cooking surface may expose the metal substrate, which corresponds to significant degradation of the coating.

[0008] To overcome the aforementioned drawbacks, the prior art describes a metal substrate coated by lamination with a fluorinated film.

[0009] Patent Document 1 describes a kitchen utensil that includes a body containing a metal substrate on which fluorinated resin films are laminated. A method for obtaining the kitchen utensil is also described. In Example 1, a multilayer PTFE film is used without any information regarding the properties of the layers.

[0010] Patent Document 2 describes a method for obtaining a metal substrate coated with a fluorinated film (without a primer layer containing an organic compound or adhesive). The fluorinated film is a multilayer film obtained by sequentially depositing aqueous dispersions of layer components (fluorinated resin and optionally inorganic fillers) onto a support, which is then dried and sintered. The multilayer film is then removed from its support and placed on a metal substrate before assembly. The layer of the fluorinated film in contact with the metal consists of PTFE and a resin selected from FEP, PFA, TFM, MFA (or mixtures thereof) having good flow properties, thus enabling good adhesion that PTFE does not allow. The metal substrate / fluorinated film assembly is manufactured by thermal compression, static pressing, or even roll-to-roll process.

[0011] Non-stick cooking surfaces derived from polymer films allow for products with high coating thicknesses, ensuring improved durability of the non-stick effect.

[0012] Furthermore, these surfaces have a very smooth surface with few defects, which enhances their non-stick properties.

[0013] However, because the surfaces of such cooking utensils are very smooth, visible defects can appear over time. In fact, polymer materials have relatively weak mechanical properties, especially at high temperatures, so the use of utensils like spatulas can create scratches that degrade the visual appearance of the surface. These scratches, even if not very deep, are all the more noticeable on a smooth cooking surface.

[0014] Furthermore, the extremely smooth surface of such cookware contributes to the easy propagation of scratches. Moreover, because the surface of such cookware is so smooth and glossy, any potential surface defects in the film polymer or defects that occur during the manufacture of the cookware are particularly visible and detract from the aesthetic appearance of the cookware. [Prior art documents] [Patent Documents]

[0015] [Patent Document 1] Korean Patent Application No. 20150030719 (KR20150030719) [Patent Document 2] Korean Patent Application No. 20160099388 (KR20160099388) [Overview of the project] [Problems that the invention aims to solve]

[0016] From an industrial perspective, there remains a need to develop cooking elements that include a metal substrate coated with a polymer film forming the cooking surface, which can delay the appearance of visible defects on the cooking surface, such as scratches, and limit the visualization of cosmetic defects on the cooking surface. [Means for solving the problem]

[0017] Accordingly, the applicant has developed a cooking element comprising a metal substrate coated with a polymer film, the surface of which is textured, which allows for the limitation of the visualization of cosmetic defects and defects that appear during the service life of the cooking element, and enables the sustained maintenance of nonstick performance. The features of the cooking element according to the present invention facilitate the use of metal utensils for stirring food and facilitate the cooking of hard foods such as shellfish.

[0018] The applicant has also developed a method for obtaining such a cooking element, which includes the step of creating a structure that constitutes a relief on the cooking surface of the cooking element.

[0019] Summary of the Invention The inventors have discovered that by generating a structure that forms a relief on the cooking surface (4) of a cooking element (1) which includes an assembled metal substrate (2) and a film (3), it is possible to limit the visualization of cosmetic defects and defects such as scratches that may appear over time.

[0020] A first object of the present invention relates to a coated cooking element (1) for cooking utensils or electric cooking appliances, comprising a metal substrate (2) coated on at least one surface (2a) by a film (3) forming a cooking surface (4), The film (3) includes a layer (3a) positioned on the opposite side of the cooking surface (4), and the layer (3a) includes 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 surface (2a) of the metal substrate (2). As a result, the cooking surface (4) has a structure (5) that constitutes a relief characterized by a maximum profile height Rt of 10 to 500 μm, preferably 20 to 100 μm, as measured according to the standard DIN 4768E of January 1, 1990.

[0021] The present invention also relates to a method for manufacturing a coated cooking element (1) for a cookware or electric cookware, comprising a cooking surface (4) having a structure (5) constituting a relief characterized by a maximum profile height Rt of 10 to 500 μm, preferably 20 to 100 μm, as measured according to the standard DIN 4768E of January 1, 1990. The method described above involves the following sequence of steps i through v: i. Supply a metal substrate (2), ii. Optionally, pretreatment of the surface (2a) of the metal substrate (2) that is intended to be coated. iii. Supplying a film (3) that forms a cooking surface (4) including a layer (3a) containing one or more semi-crystalline or amorphous thermoplastic polymers, iv. Positioning the layer (3a) of the film (3) such that the layer (3a) of the film (3) faces the surface (2a) of the metal substrate (2), v. Executing the assembly of the metal substrate (2) and the film (3) by hot pressing, including, The method further includes step vi. of creating the structure (5), and steps v. and vi. may be simultaneous or sequential.

[0022] The present invention also relates to a cooking article (100) comprising not only a coated cooking element (1) obtained according to the present invention or according to the method of the present invention, but also an electric cooking appliance (200) comprising the 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 according to the method of the present invention.

[0023] Another aspect of the present invention is as described in the claims below.

[0024] Definitions The term "film" is to be understood in the context of the present invention as an assembly composed of one or more superposed layers intended to be assembled with a metal substrate. Once assembled with a metal substrate, the term "film" also applies to the resulting assembly.

[0025] The term "layer" is to be understood in the context of the present invention as meaning a continuous layer. A continuous layer (also called a monolithic layer) is a single entity that forms a completely flat area that completely covers the surface on which it is placed or is intended to be placed.

[0026] In the context of this invention, the term "hot press" is understood to mean a method for assembling a preheated metal substrate (2) and a film (3) between a lower tool and an upper tool.

[0027] In the context of this invention, the term "aluminum alloy" is understood to refer to aluminum alloys of the Series 1000, 2000, 3000, 4000, 5000, 6000, 7000, and 8000.

[0028] The term "Maximum profile height Rt measured according to standard DIN 4768E of January 1, 1990" is understood to mean the distance between the line and the line hollows corresponding to the deepest depth within the measurement interval (reference section) of the filtered profile, according to standard DIN 4768E of January 1, 1990.

[0029] Surface topography can be studied, in particular, using a profile meter equipped with a probe featuring a thin stylus with a diamond tip, or by Altisurf® type optical measuring instruments where a confocal chromatic sensor enables non-contact measurement.

[0030] In the context of this invention, the term "cooking utensil" shall be understood as an object intended for cooking. To this end, it is intended to be heated to cook or reheat food carried by a cooking element or contained within a cooking element.

[0031] The expression "an object intended to be heated to cook or reheat food carried by or contained within a cooking element" is understood in the sense of the present invention to mean an object heated by an external heating system such as a cooking hob, which may in particular be a frying pan, saucepan, sauté pan, wok, or barbecue grill, and which can transfer the heat provided by the external heating system to materials or food in contact with the object.

[0032] In the context of this invention, the term "electric cooking appliance" shall be understood as an object intended for cooking. To do so, it is designed to generate heat.

[0033] In the context of this invention, the phrase "an object designed to generate heat" is understood to mean a heating object having its own heating system. [Brief explanation of the drawing]

[0034] [Figure 1] The image 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. [Figure 2] A cross-sectional view of an exemplary embodiment of a coated cooking element (1) according to the method of the present invention, including a film (3) and a metal substrate (2), is shown. [Figure 3] The diagram shows a schematic cross-sectional view of a coated cooking element (1), which includes 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. [Figure 4]The diagram shows a cross-sectional view of an exemplary embodiment of a coated cooking element (1) comprising a film (3) and a metal substrate (2) prior to assembly according to the method of the present invention, the method comprising the 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 the plane of the upper tool (12B) that contacts the cooking surface (4) has a texture (6). [Figure 5] The diagram shows a cross-sectional view of an exemplary embodiment of a coated cooking element (1) including a film (3) and a metal substrate (2) prior to assembly according to the method of the present invention, the method including the step of assembling the film (3) and the metal substrate (2) by pressing them between a lower tool (12A) and an upper tool (12B) of a press, the textured spacer (7) being positioned facing the cooking surface (4) during assembly. [Figure 6] The coated cooking element (1) according to the present invention, which forms a cooking receptacle, is shown. [Figure 7] Figure 6 shows a cooking utensil (100) equipped with a coated cooking element (1). [Figure 8] Figure 6 shows an electric cooking appliance (200) equipped with a coated cooking element (1). [Modes for carrying out the invention]

[0035] The inventors have developed a coated cooking element (1) for cooking utensils or electric cooking appliances that meets the described needs, and a method for obtaining such a coated cooking element (1).

[0036] Cooking element The present invention also relates to a coated cooking element (1) for cooking utensils or electric cooking appliances, comprising a metal substrate (2) coated on at least one surface (2a) by a film (3) forming a cooking surface (4), The film (3) includes a layer (3a) located on the opposite side of the cooking surface (4), and the layer (3a) includes one or more semicrystalline or amorphous thermoplastic polymers. 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). As a result, the cooking surface (4) has a structure (5) that constitutes a relief characterized by a maximum profile height Rt of 10 to 500 μm, preferably 20 to 100 μm, as measured according to the standard DIN 4768E of January 1, 1990.

[0037] Metal substrate (2) The metal substrate (2) that can be used in the context of the present invention may, advantageously, include a substrate made of aluminum, stainless steel, cast iron, or aluminum, titanium, or copper.

[0038] In the context of this invention, aluminum is understood to be a metal composed of 100% aluminum or an aluminum alloy.

[0039] Advantageously, the metal substrate (2) may be made of aluminum or stainless steel, or it may be a multilayer metal substrate, particularly a two-layer, three-layer, or four-layer substrate, where these multiple layers can be obtained, for example, by co-lamination, by thermal diffusion under load (solid bonding), or by hot or cold impact bonding.

[0040] Preferably, the metal substrate (2) comprises alternating layers of metal and / or metal alloy.

[0041] According to one embodiment, the metal substrate (2) is a substrate made of aluminum or a stainless steel alloy, or a multilayer metal substrate in which the surface (2a) is made of aluminum or a stainless steel alloy.

[0042] Preferably, the metal substrate (2) is an aluminum substrate.

[0043] Advantageously, the thickness of the metal substrate (2) is between 0.5 mm and 10 mm.

[0044] Advantageously, the surface (2a) of the metal substrate (2) is surface-treated to improve the adhesion of the film (3) to the substrate before assembly.

[0045] According to one embodiment, the surface (2a) of the metal substrate (2) is surface-treated, and the surface treatment is chemical etching, brushing, hydration, sandblasting, shot peening, physicochemical plasma, corona or laser treatment, chemical activation, or a combination of these different techniques.

[0046] Advantageously, the arithmetic mean roughness Ra of the surface (2a) of the metal substrate (2) is 1 μm or greater.

[0047] 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. Surface topography can be studied, in particular, using a profile meter with a probe equipped with a thin stylus having a diamond tip, or by an Altisurf® type optical measuring instrument where a confocal chromatic sensor enables non-contact measurement. Studying this surface topography data makes it possible to define the arithmetic mean roughness Ra.

[0048] Advantageously, the cooking element (1) does not include a metal oxide intermediate layer between the metal substrate (2) and the film (3) described below.

[0049] Film (3) The film (3) comprises a layer (3a) containing one or more semicrystalline or amorphous polymers, the layer (3a) being intended to be positioned in contact with the surface (2a) of the metal substrate (2).

[0050] According to one embodiment, one or more semicrystalline or amorphous thermoplastic polymers of layer (3a) are - Polytetrafluoroethylene (PTFE), copolymers of tetrafluoroethylene and perfluoropropyl vinyl ether (PFA), copolymers of tetrafluoroethylene and hexafluoropropene (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), ethylenetetrafluoroethylene (ETFE), and mixtures thereof. - Polyaryl ether ketones (PAEK), preferably polyether ether ketone (PEEK), include polyether ether ketone (PEK), polyether ether ketone (PEEK), polyether ketone ketone (PEKK), polyether ether ketone ketone (PEEKK), and polyether ketone ether ketone ketone (PEKEKK). - Polyamide-imide (PAI), polyimide (PI), polyetherimide (PEI), polybenzymidazole (PBI), - and mixtures thereof, Selected from.

[0051] The melting points of PTFE and semicrystalline thermoplastic polymers, as well as the glass transition temperatures (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 otherwise by dynamic mechanical analysis (DMA).

[0052] The film (3) may also consist of a single layer (3a) that forms the cooking surface (4).

[0053] According to another configuration, the film (3) may also include an additional layer placed on top of the layer (3a), as described above. In this case, the film (3) further includes another layer (3b) that forms the cooking surface (4), and the other layer (3b) is - Polytetrafluoroethylene (PTFE), copolymers of tetrafluoroethylene and perfluoropropyl vinyl ether (PFA), copolymers of tetrafluoroethylene and hexafluoropropene (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), ethylenetetrafluoroethylene (ETFE), and mixtures thereof, preferably PTFE. - Polyaryl ether ketones (PAEK), preferably polyether ether ketone (PEEK), include polyether ether ketone (PEK), polyether ether ketone (PEEK), polyether ketone ketone (PEKK), polyether ether ketone ketone (PEEKK), and polyether ketone ether ketone ketone (PEKEKK). - Polyamide-imide (PAI), polyimide (PI), polyetherimide (PEI), polybenzmidazole (PBI), - and mixtures thereof, preferably a mixture of PTFE and PEEK, It contains one or more polymers selected from the following.

[0054] According to one embodiment, the film (3) further includes at least one intermediate layer (3c) disposed between layer (3a) and other layers (3b), the intermediate layer (3c) is - Polytetrafluoroethylene (PTFE), copolymer of tetrafluoroethylene and perfluoropropyl vinyl ether (PFA), copolymer of tetrafluoroethylene and hexafluoropropene (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), ethylenetetrafluoroethylene (ETFE), and mixtures thereof, preferably copolymer of tetrafluoroethylene and perfluoropropyl vinyl ether (PFA) and PTFE, preferably PTFE, - Polyether ketone (PEK), polyether ether ketone (PEEK), polyether ketone ketone (PEKK), polyether ether ketone ketone (PEEKK), polyether ketone ether ketone ketone (PEKEKK), preferably polyaryl ether ketone (PAEK) containing polyether ether ketone (PEEK), - Polyamide-imide (PAI), polyimide (PI), polyetherimide (PEI), polybenzmidazole (PBI), - and mixtures thereof, preferably a mixture of polyarylether ketone (PAEK) and PTFE, preferably a mixture of PEEK and PTFE; It comprises one or more polymers selected from, PTFE is particularly preferred.

[0055] The film (3) may further include at least one filler and / or at least one reinforcing material.

[0056] Fillers that may be used in the context of the present invention include, in particular, metal oxides, metal carbides, metal oxynitrides, metal nitrides, silica, and mixtures thereof.

[0057] These fillers may be present in one or more layers of the film (3) or in each of the layers of the film (3).

[0058] Reinforcements that may be used in the context of the present invention include fibrous mineral or metal reinforcements, metal meshes, glass fiber materials, or fabrics. The reinforcement may also consist of a non-fluorinated polymer having high thermomechanical properties, such as polyetheretherketone (PEEK) or polyaryletherketone (PEAK) type polyamideimide (PAI). The reinforcement may also be in the form of a layer of film (3) placed between layer (3a) and other layers (3b) that form the cooking surface.

[0059] To improve the adhesion between the film (3) and the metal substrate (2), the layer (3a) of the film (3) that contacts the surface (2a) of the metal substrate (2) in step (v) may be subjected to 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.

[0060] According to another embodiment, the thickness of the film (3) is 10 μm to 500 μm, preferably 15 μm to 250 μm, and particularly preferably 25 μm to 150 μm.

[0061] The thickness of one or more layers of the film (3) is measured at 20 random points on the cross-section of the film. The average thickness of the film (3) is obtained by taking the average of these 20 measurements.

[0062] The total thickness of the film (3) of the coated cooking element (1) according to the present invention, in other words, the thickness measured on the cooking element once it has been coated with the film (3), is 10 μm to 500 μm, preferably 15 μm to 250 μm, and particularly preferably 25 μm to 150 μm.

[0063] The thickness of the film (3) of the coated cooking element (1) according to the present invention is measured at 20 random points on a section of the coated substrate. The average thickness of the film (3) is obtained by taking the average of these 20 measurements.

[0064] The film (3) can be obtained by depositing a first layer onto a support, then optionally depositing other layers sequentially, and then by exfoliation of the film to separate it from the support, before assembling it with the metal substrate (2). The layers of the film (3) can also be assembled by any other assembly method, such as lamination.

[0065] Advantageously, the film (3) of the coated cooking element (1) covers the entire surface (2a) of the metal substrate (2).

[0066] In the exemplary embodiments shown in Figures 1, 2, 4, and 5, the film (3) comprises three layers: a layer (3a), another layer (3b), and an intermediate layer (3c).

[0067] Structure (5) The cooking surface (4) of the cooking element (1) described below has a structure (5) that constitutes a relief characterized by a maximum profile height Rt measured according to the standard DIN 4768E of January 1, 1990, which is 10 to 500 μm, preferably 20 to 100 μm.

[0068] The creation of structures (5) on the cooking surface (4) makes the surface less smooth and less glossy, and thus can limit the visibility of defects, whether they are cosmetic defects or scratches that may appear during use.

[0069] The generation of reliefs characterized by a maximum profile height Rt exceeding 10 μm, preferably 20 μm, allows for the visual masking of these defects and flaws.

[0070] However, the maximum profile height Rt must remain limited so as not to degrade the performance as a cooking surface, and therefore must avoid, for example, preferential soiling areas in the hollow presented by the relief. Thus, it is less than 500 μm, preferably less than 100 μm.

[0071] The film (3) of the coated cooking element (1) has a non-uniform thickness due to the structure (5) present on the cooking surface (4). It has a non-zero minimum thickness or residual thickness, indicated as Er, such that the surface (2a) of the metal substrate (2) is completely covered by the film (3).

[0072] This residual thickness Er maintains the nonstick properties even in the case of scratches or progressive wear in the relief area of ​​the film (3).

[0073] According to one embodiment, the residual thickness Er of the film (3) is 10 μm or more, preferably 20 μm or more.

[0074] The residual thickness Er of the film (3) is measured on a section of the coated cooking element (1).

[0075] The maximum profile height Rt of structure (5) may be 20% to 180%, preferably 50% to 150%, and particularly preferably 80% to 120%, of the thickness of the film (3).

[0076] The thickness of the film (3) of the coated cooking element (1) is measured according to the protocol described above.

[0077] The relief of structure (5) includes a pattern formed by local variations in the surface level of the cooking surface (4).

[0078] According to one embodiment, the relief of structure (5) includes or is composed of a periodic pattern.

[0079] In this case, the relief of structure (5) may include the same basic pattern repeated at regular intervals, or may consist of the same basic pattern repeated at regular intervals.

[0080] Advantageously, the relief of structure (5) is composed of patterns having a step Ar at a distance from each other, corresponding to the distance between two relief patterns of more than 100 μm, preferably more than 150 μm, and even more preferably more than 200 μm.

[0081] Advantageously, the relief of structure (5) does not contain a periodic pattern or consists of patterns that are far apart from each other by step Ar, corresponding to the distance between two relief patterns of more than 100 μm, preferably more than 150 μm, and even more preferably more than 200 μm.

[0082] Figure 3 shows a schematic cross-sectional view of a coated cooking element (1) including a metal substrate (2) coated with a film (3) forming a cooking surface (4), the cooking surface (4) having a periodic structure (5) with a maximum profile height Rt and having a periodic profile of step Ar. The surface (2a) of the metal substrate (2) is shown to have surface roughness.

[0083] As shown in Figure 3, the point on the film (3) with the lowest elevation rises to a higher elevation than the point on the metal substrate (2) with the highest elevation. Thus, as is clearly seen in Figure 3, the film (3) forms a continuous base (3d) on the metal substrate (2), and the structure (5) is formed on the continuous base (3d). In Figure 3, the minimum thickness or residual thickness indicated by Er corresponds to the thickness of the continuous base (3d). The residual thickness Er of the film (3) is smaller than the initial thickness Ef, which corresponds to the thickness of the film (3) as defined above.

[0084] Therefore, the notch affecting the film (3) is first related to the structure (5) and then to the continuous base (3d). The notch requires a greater depth to reach the metal substrate (2).

[0085] According to one embodiment, the relief of structure (5) includes or is composed of a non-periodic pattern.

[0086] In the alternative, the relief of structure (5) may include periodic patterns and / or non-periodic patterns.

[0087] Structure (5) generates inequalities in the thickness of the film (3), which results in variations in scratch resistance on the surface, which may contribute to preventing the formation of long scratches.

[0088] Structure (5) may be present on all or part of the cooking surface (4).

[0089] Manufacturing method The present invention also relates to a method for manufacturing a coated cooking element (1) for a cookware or electric cookware, comprising a cooking surface (4) having a structure (5) constituting a relief characterized by a maximum profile height Rt of 10 to 500 μm, preferably 20 to 100 μm, as measured according to the standard DIN 4768E of January 1, 1990, The above method involves the following sequential steps i. to v. i. Supply a metal substrate (2), ii. Optionally, pretreatment of the surface (2a) of the metal substrate (2) that is intended to be coated. iii. To supply a film (3) that forms a cooking surface (4) comprising a layer (3a) containing one or more semicrystalline or amorphous thermoplastic polymers, iv. Positioning the layer (3a) of the film (3) such that the layer (3a) of the film (3) faces the surface (2a) of the metal substrate (2), v. The assembly of the metal substrate (2) and the film (3) is carried out by hot pressing. Includes, The method further includes step vi. of creating the structure (5), wherein steps v. and vi. may be simultaneous or sequential.

[0090] The structure (5) of the cooking element (1), metal substrate (2), film (3), and cooking surface (4) is as described above.

[0091] Assembly step v) Step v., in which the metal substrate (2) and film (3) are assembled, is performed by hot pressing.

[0092] The term "hot pressing" refers to any method that can be used to assemble metal substrates and polymer films by applying high temperatures, generally higher than the lowest melting point of the semicrystalline thermoplastic polymer and the glass transition temperature (Tg) of the amorphous thermoplastic polymer of layer (3a), for a sufficient period of time ranging from one second to several minutes, generally at high pressures exceeding several MPa.

[0093] The assemblies can be manufactured by thermal compression, static pressing, or even roll-to-roll (roll-to-roll process). The pressure applied by thermal compression is generally several MPa. The operating temperature is generally limited by the degradation temperature of the polymer film being assembled.

[0094] Assembly can be performed by hot impact bonding. In this case, the pressure applied is greater than in the thermal compression method, on the order of several hundred MPa, and the impact bonding time is very short, typically on the order of a few seconds, which allows for the use of higher temperatures.

[0095] Assembly using solid joints can also be mentioned, though not as an exclusive method.

[0096] Advantageously, the temperature of the film (3) at the end of assembly step v. of the film (3) and the metal substrate (2), in other words, the temperature of the film (3) 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 point of the semicrystalline thermoplastic polymer and the glass transition temperature (Tg) of the amorphous thermoplastic polymer of the layer (3a).

[0097] After assembly, in order to obtain maximum adhesion between the metal substrate (2) and the film (3), the metal substrate (2) coated with the film (3) is allowed to cool to ambient temperature.

[0098] Step (vi) to create structure (5) Step v) of assembling the metal substrate (2) and the film (3), and step vi) of creating the structure (5), may be simultaneous or sequential.

[0099] According to a modified version of the method, structure (5) is used during the hot press in step v) or during the cold press following this hot press. - Texture (6) of the surface of the press tool that comes into contact with the cooking surface (4), The texture of the tool can be manufactured by laser or chemical etching, electrical discharge machining, or mechanical etching. - Or, a textured spacer (7) placed between the surface of the press tool and the film (3), The spacer may be a textured metal material, metal cloth, welded metal mesh, fiberglass fabric, or carbon fiber fabric. It can be created on the cooking surface (4) by any of the following means.

[0100] According to one embodiment, steps v. and vi. are performed simultaneously using a hydraulic or mechanical press including a lower tool (12A) and an upper tool (12B) in which a metal substrate (2) and a film (3) are assembled between them, so that the plane of the surface of the tool that contacts the cooking surface (4) has a texture (6) that can impart the structure (5) to the cooking surface (4).

[0101] Figure 4 shows an embodiment in which the upper tool (12B) has the texture (6).

[0102] According to another embodiment, steps v. and vi. are performed simultaneously and using a hydraulic or mechanical press including a lower tool (12A) and an upper tool (12B) in which the metal substrate (2) and film (3) are assembled between them. Between step iv. and step v., step iv(a) further comprises positioning the textured spacer (7) so that the textured spacer (7) faces the cooking surface (4) of the film (3) and the structure (5) can be applied to the cooking surface (4) during assembly step v.

[0103] Figure 5 shows such an embodiment.

[0104] According to another embodiment, steps v. and vi. are continuous, and step vi. is performed using a hydraulic or mechanical press including a lower tool (12A) and an upper tool (12B), between them, the metal substrate (2) and film (3) assembled in step v. are cold-pressed, and as a result, the planes of the surface of the tools that come into contact with the cooking surface (4) in step vi. have a texture (6) that can impart the structure (5) to the cooking surface (4).

[0105] According to another embodiment, steps v. and vi. are sequential, and step vi. is a step in which the metal substrate (2) and film (3) assembled in step v. are cold-pressed in step vi. with a textured spacer (7) which is positioned facing the cooking surface (4) and can impart the structure (5) to the cooking surface (4).

[0106] During step vi., the film (3) flows into the pattern of the textured spacer (7) or into the hollows of the texture (6) on the surface of the press tool, thus enabling the creation of the structure (5).

[0107] According to the method carried out in step vi., deformation of the film (3) can be generated with or without deformation of the metal substrate (2), depending on the desired maximum profile height Rt and the thickness of the film (3).

[0108] Next, the metal substrate (2), whose cooking surface (4) is coated with a film (3) having a structure (5), can be molded by stamping and, if applicable, stretching.

[0109] According to another modification of this method, the structure (5) of the cooking surface (4) can also be manufactured by mechanical wear of the surface of the film (3).

[0110] The aforementioned structure (5) is, - Immediately after the assembly of the film (3) and the metal substrate (2), - Or, after the shaping step of the cooking element (1), It can be generated in one of the following ways.

[0111] According to one embodiment, steps v. and vi. are sequential, and step vi. is a mechanical processing step of the cooking surface (4) of the metal substrate (2) and the film (3) assembled in step v. The mechanical treatment may be brushing, emery grinding, sandblasting, shot blasting, microshot blasting, shot peening, or a combination of these techniques.

[0112] The mechanical treatment may be brushing, emery grinding, sandblasting, shot blasting, microshot blasting, shot peening, or a combination of these techniques.

[0113] Abrasives are used for the mechanical treatment of the cooking surface (4), and their properties (nature, shape, size) are selected as a function of the desired structure (5) of the cooking surface (4).

[0114] For example, it is possible to place the elements to be textured on a lathe and thus generate a structure (5) having a circular pattern.

[0115] Next, the metal substrate (2) coated with the film (3) can be formed by stamping and, if applicable, by stretching.

[0116] The adhesion of the film (3) to the metal substrate (2) before molding must be sufficient to avoid loss of adhesion during and after the molding operation.

[0117] The shaping of the metal substrate (2) coated with the film (3) may be performed before step vi., in which the structure (5) is created by mechanical treatment of the cooking surface (4).

[0118] According to one embodiment, the method thus further includes, between steps v. and vi. of mechanical processing, a step v(a) of forming the metal substrate (2) and film (3) assembled in step v. by stamping and, if applicable, stretching.

[0119] Step vi., which creates the structure (5), is performed on all or part of the cooking surface (4).

[0120] Figure 6 shows a coated cooking element (1) according to the present invention that forms a cooking container. The metal substrate (2) and assembled film (3) form a cooking surface (4) located on the inside of the cooking container.

[0121] cooking supplies Another object of the present invention relates to a cooking utensil (100) comprising a coated cooking element (1) obtained as described above or by the method described above.

[0122] A cooking element (1) coated by the method of the present invention can form a cooking container within a cooking utensil (100).

[0123] According to one embodiment shown in Figure 7, the cooking utensil (100) has a heating surface (6) intended to be positioned in contact with an external heat source, and the heating surface (6) is on the opposite side of a cooking surface (5) intended to be positioned in contact with food during cooking. The cooking utensil (100) further comprises a gripping member (9) fixed to the coated cooking element (1).

[0124] According to one embodiment, the cooking utensil (100) comprises a coated cooking element (1) including a bottom (10) and side walls (11), the cooking surface (4) having the structure (5) on the bottom.

[0125] According to a modified example of this embodiment, only the bottom (10) has the structure (5).

[0126] According to another modification of this embodiment, the bottom (10) and the side wall (11) have a structure (5).

[0127] The structure (5) preferably extends over the entire bottom (10).

[0128] When it is located on the side wall (11), the structure (5) does not necessarily extend across the entire side wall (11).

[0129] According to a preferred embodiment, the entire cooking surface (4) of the coated cooking element (1) has a structure (5). The coated cooking element (1) is then formed by stamping and, if applicable, stretching, such that the bottom (10) and side walls (11) have a structure (5).

[0130] According to a preferred embodiment, after stamping and, if applicable, after stretching, only the bottom (10) of the cooking element (1) of the cooking utensil (100) has the structure (5).

[0131] Cooking utensils (100) may be selected from the group consisting of saucepans, frying pans, fondue or raclette pans or pots, stew pots, woks, sauté pans, crepe makers, grills, plancha grills, cooking pots, casseroles, containers for cooking appliances or bread-making machines, and cooking molds.

[0132] Electric cooking appliances Another object of the present invention relates to an electric cooking appliance (200) comprising a coated cooking element (1) obtained by or by the above-described method, and a heating source (210) designed to heat the coated cooking element (1).

[0133] A cooking element (1) coated by the method of the present invention can form a cooking container inside an electric cooking appliance (200).

[0134] According to the embodiment shown in Figure 8, the electric cooking appliance (200) according to the present invention comprises a coated cooking element (1) and a heating source (210) designed to heat the coated cooking element (1). The coated cooking element (1) forming a cooking container is placed on a heating base (230) which comprises a heating source (210) consisting of a plurality of (220). The surface (8) rests on the heating element (220). If necessary, the surface (8) can be rigidly attached to the heating element (220).

[0135] According to one embodiment, the electric cooking appliance (200) comprises a coated cooking element (1) including a bottom (10) and side walls (11), the cooking surface (4) having the structure (5) on the bottom.

[0136] According to a modified example of this embodiment, only the bottom (10) has the structure (5).

[0137] According to another modification of this embodiment, the bottom (10) and the side wall (11) have a structure (5).

[0138] The structure (5) preferably extends over the entire bottom (10). When it is located on the side wall (11), the structure (5) does not necessarily extend across the entire side wall (11).

[0139] The electric cooking appliance (200) may be selected from the group consisting of an electric crepe maker, an electric raclette appliance, an electric fondue appliance, an electric grill, an electric plancha grill, an electric rice cooker, and a bread maker.

Claims

1. A coated cooking element (1) for cooking utensils or electric cooking appliances, comprising a metal substrate (2) coated on at least one surface (2a) by a film (3) that forms a cooking surface (4), The film (3) includes a layer (3a) located on the opposite side of the cooking surface (4), and the layer (3a) includes one or more semicrystalline or amorphous thermoplastic polymers. 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). As a result, the cooking surface (4) is a coated cooking element (1) having a structure (5) that constitutes a relief characterized by a maximum profile height Rt of 10 to 500 μm, preferably 20 to 100 μm, as measured according to the standard DIN 4768E of January 1, 1990.

2. The coated cooking element (1) according to claim 1, characterized in that the metal substrate (2) is a substrate made of aluminum or stainless steel, or a multilayer metal substrate.

3. The coated cooking element (1) according to claim 1 or 2, characterized in that the surface (2a) of the metal substrate (2) is surface-treated before the film (3) is assembled with the surface (2a) of the metal substrate (2).

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

5. The coated cooking element (1) according to any one of claims 1 to 4, characterized in that the residual thickness Er of the film (3) is 10 μm or more, preferably 20 μm or more.

6. The crystalline or amorphous thermoplastic polymer in the layer (3) is - Polytetrafluoroethylene (PTFE), copolymers of tetrafluoroethylene and perfluoropropyl vinyl ether (PFA), copolymers of tetrafluoroethylene and hexafluoropropene (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), ethylenetetrafluoroethylene (ETFE), and mixtures thereof. - Polyaryl ether ketone (PAEK), preferably polyether ether ketone (PEEK), containing polyether ether ketone (PEK), polyether ether ketone (PEEK), polyether ether ketone (PEKK), polyether ether ketone (PEKEKK), - Polyamide-imide (PAI), polyimide (PI), polyetherimide (PEI), polybenzmidazole (PBI), - and mixtures thereof, A coated cooking element (1) according to any one of claims 1 to 5, characterized in that it is selected from among.

7. The coated cooking element (1) according to any one of claims 1 to 6, characterized in that the film (3) is also composed of a single layer (3a) that forms the cooking surface (4).

8. The film (3) further includes another layer (3b) that forms the cooking surface (4), and the other layer (3b) is - Polytetrafluoroethylene (PTFE), copolymer of tetrafluoroethylene and perfluoropropyl vinyl ether (PFA), copolymer of tetrafluoroethylene and hexafluoropropene (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), ethylenetetrafluoroethylene (ETFE), and mixtures thereof, preferably PTFE. - Polyaryl ether ketone (PAEK), preferably polyether ether ketone (PEEK), containing polyether ether ketone (PEK), polyether ether ketone (PEEK), polyether ether ketone (PEKK), polyether ether ketone (PEKEKK), - Polyamide-imide (PAI), polyimide (PI), polyetherimide (PEI), polybenzmidazole (PBI), - and mixtures thereof, preferably a mixture of PTFE and PEEK, A coated cooking element (1) according to any one of claims 1 to 6, characterized by comprising one or more polymers selected from the following.

9. The film (3) further includes at least one intermediate layer (3c) disposed between the layer (3a) and the other layer (3b), the intermediate layer (3c) is - Polytetrafluoroethylene (PTFE), copolymer of tetrafluoroethylene and perfluoropropyl vinyl ether (PFA), copolymer of tetrafluoroethylene and hexafluoropropene (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), ethylenetetrafluoroethylene (ETFE), and mixtures thereof, preferably copolymer of tetrafluoroethylene and perfluoropropyl vinyl ether (PFA) and PTFE, preferably PTFE, - Polyaryl ether ketone (PAEK), preferably polyether ether ketone (PEEK), containing polyether ether ketone (PEK), polyether ether ketone (PEEK), polyether ether ketone (PEKK), polyether ether ketone (PEKEKK), - Polyamide-imide (PAI), polyimide (PI), polyetherimide (PEI), polybenzmidazole (PBI), - and mixtures thereof, preferably a mixture of polyarylether ketone (PEEK) and PTFE, preferably a mixture of PEEK and PTFE, The coated cooking element (1) according to claim 8, characterized by comprising one or more polymers selected from, with PTFE being particularly preferred.

10. The coated cooking element (1) according to any one of claims 1 to 9, 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 electric cooking appliance, comprising a cooking surface (4) having a structure (5) that constitutes a relief characterized by a maximum profile height Rt measured according to the standard DIN 4768E of January 1, 1990, of 10 to 500 μm, preferably 20 to 100 μm, the cooking element (1), The above method consists of the following sequential steps i. to v.: i. Supplying a metal substrate (2), ii. Optionally, pretreatment of the surface (2a) of the metal substrate (2) that is intended to be coated. iii. To supply a film (3) that forms a cooking surface (4) including a layer (3a) containing one or more semicrystalline or amorphous thermoplastic polymers, iv. Arranging the layer (3a) of the film (3) such that the layer (3a) faces the surface (2a) of the metal substrate (2), v. The assembly of the metal substrate (2) and the film (3) is carried out by hot pressing. Includes, A method for producing a coated cooking element (1), further comprising step vi. of creating the structure (5), wherein steps v. and vi. may occur simultaneously or sequentially.

12. Steps v. and vi. are performed simultaneously and are carried out using a hydraulic or mechanical press including a lower tool (12A) and an upper tool (12B) in which the metal substrate (2) and the film (3) are assembled between them. The method according to claim 11, characterized in that, as a result, the flat surface of the tool that comes into contact with the cooking surface (4) has a texture (6) that can impart the structure (5) to the cooking surface (4).

13. Steps v. and vi. are performed simultaneously and using a hydraulic or mechanical press including a lower tool (12A) and an upper tool (12B) to assemble the metal substrate (2) and the film (3) between them. The method according to claim 11, further comprising step iv(a) between step iv. and step v., in which a textured spacer (7) is positioned such that the textured spacer (7) faces the cooking surface (4) of the film (3) and the structure (5) can be applied to the cooking surface (4) during assembly step v.

14. The method according to claim 11, wherein steps v. and vi. are continuous, and step vi. is performed using a hydraulic or mechanical press including a lower tool (12A) and an upper tool (12B), between them, the metal substrate (2) and film (3) assembled in step v. are cold-pressed, and as a result, the plane of the surface of the tool that comes into contact with the cooking surface (4) in 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 continuous, and step vi. is a step of cold pressing the metal substrate (2) and film (3) assembled in step v. using a textured spacer (7) which is positioned in step vi. facing a cooking surface (4) and which can give the cooking surface (4) the structure (5).

16. The method according to claim 11, characterized in that steps v. and vi. are continuous, and step vi. is a step of mechanical treatment of the cooking surface (4) and the film (3) of the metal substrate (2) assembled in step v.

17. The method according to claim 16, characterized in that the mechanical treatment is brushing, emery grinding, sandblasting, shot blasting, microshot blasting, shot peening, or a combination thereof.

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

19. The method according to any one of claims 11 to 18, characterized in that step vi., which creates the structure (5), is performed 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 the method described in any one of claims 11 to 19.

21. A cooking utensil (100) according to claim 20, comprising a heating surface (8) intended to be positioned in contact with an external heat source, wherein the heating surface (8) is on the opposite side of a cooking surface (4) intended to be positioned in contact with food during cooking.

22. The cooking utensil according to claim 21, characterized in that the cooking element (1) includes a bottom and side walls, and the cooking surface (4) has the structure (5) at the bottom.

23. Cooking utensils (100) according to any one of claims 20 to 22, selected from the group consisting of pots, pans, fondue or raclette pots or pans, stew pots, woks, sauté pans, crepe makers, grills, plancha grills, cooking pots, pans, containers for cooking appliances or bread makers, and cooking molds.

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), wherein the coated cooking element (1) is as described in any one of claims 1 to 10 or obtained according to the method described in any one of claims 11 to 19.

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

26. An electric cooking appliance (200) according to claim 24 or 25, characterized in that it is selected from the group consisting of an electric crepe maker, an electric raclette appliance, an electric fondue appliance, an electric grill, an electric plancha grill, an electric rice cooker, and a bread maker.

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