Polymeric sublayer - formulation based on resins with high thermomechanical properties (PEEK, PES, PAI, PBI, etc.) to enhance the mechanical resistance of the fluorocoating, especially its resistance to heat

Abstract

The present invention relates to a bonding auxiliary layer of a liquid repellent coating on a metal support, comprising: a) 20% by weight to 80% by weight of the total weight of said auxiliary layer of one or more polymers selected from the group consisting of polyaryletherketones (PAEK), polyethyleneimines (PEI), polyimides (PI), polyamideimides (PAI) and polybenzimidazoles (PBI), having a weight ratio PEAK:(PEI+PI+PAI+PBI) of 1:1 to 15:1; and b) at least 20% by weight of the total weight of said auxiliary layer, preferably The auxiliary layer is characterized by comprising at least 25% by weight of one or more polymers selected from the group consisting of phenylene polysulfide (PPS) and polyethylene sulfone (PES); c) a reinforcing inorganic filler that is less than 40% by weight, preferably less than 30% by weight, of the total weight of the auxiliary layer, and preferably between 5% and 25% by weight; d) one or more fluorocarbon or acrylic resins that are 0% to 5% by weight of the total weight of the auxiliary layer; and e) optionally one or more pigments.

Description

[Technical field]

[0001] The present invention finds application in the field of anti-stick coatings for cooking surfaces of cookware and electric cookware. [Background technology]

[0002] PTFE (Polytetrafluoroethylene) coated cookware is popular on the market because it allows cooking with little or no oil addition and is easy to maintain. However, an inherent weakness of these coatings is their low mechanical resistance, especially at high temperatures.

[0003] To overcome this, numerous technical solutions have been proposed, consisting in strengthening the coating with hard fillers or by the interposition of hard auxiliary layers of inorganic or organic type.

[0004] In the case of bases reinforced with hard organic or inorganic fillers, a significant improvement in abrasion resistance is indeed observed, but also an effect on metal when cooking foods such as pork ribs or when using metal spatulas.

[0005] In the case of hard inorganic bases, such as those made from enamel or metal oxides, the abrasion resistance is further improved, however the impact problems are limited without being eliminated.

[0006] Organic polymer auxiliary layers are also known. These auxiliary layers in fact make it possible to significantly reduce or even eliminate the appearance of scratches. This strategy is therefore of great interest. The polymers used are very often thermoplastics with high heat resistance and high melting points, such as, for example, polyaryletherketones, in particular oxy-1,4-phenylenephenylene-oxy-1,4-phenylene-carbonyl-1,4-phenylene or PEEK, or other phenylene sulfides.

[0007] PEEK polymer is of interest in culinary applications because it has a high melting point (343°C) and excellent thermal stability under service conditions at 260°C.

[0008] To obtain a sublayer from this type of polymer, the following coating techniques can be implemented: spray coating, roller coating, curtain coating, pad printing, screen printing, thermal projection, electrostatic spraying, inkjet.

[0009] WO 2000 / 54895 discloses the use of an auxiliary layer consisting solely of PEEK (particle size 5 μm to 100 μm, preferably d50 20 μm) deposited on a metal substrate, with a coverage of 60% to 95% of the surface of the article and then covered with a single or multi-layer anti-adhesive coating based on fluororesins and fluorocopolymers. The PEEK auxiliary layer is deposited either by pad or screen printing or by spraying in the form of a dispersion.

[0010] The thickness of this PEEK layer is comprised between 5 μm and 100 μm.

[0011] A drawback of the described method is that it requires a double baking of the fluorinated coating based on PEEK. The first cooking requires a temperature higher than the melting point of the polymer constituting the auxiliary layer (i.e. 380-400 ° C for PEEK) to allow adhesion to the metal substrate. The article must then be cooled substantially, which is very costly in terms of time and energy, but is essential to be able to apply the successive fluorinated layers, which are sintered during a second baking at high temperatures (> 420 ° C).

[0012] WO 2010 / 130954 describes a hard auxiliary layer that forms a continuous network discontinuously deposited on the inside bottom of the cookware. The material that constitutes this layer is ceramic (alumina-titanium mixture) or metal or polymer (PAI, PEI, PI, PES, PPS, PEK or PEEK). The surface of the cookware covered with this material is constituted by 30% to 80% and the dimensions between the deposited droplets are constituted by 2 μm to 50 μm. The surface of this hard layer has a roughness with Ra of 2 μm to 12 μm, preferably 4 μm to 8 μm.

[0013] This material is sprayed by the flame spray method in powder form, preferably with a particle size comprised between 20 μm and 45 μm. Prior to powder deposition by spray flame above 180°C, the metal substrate needs to be strongly preheated.

[0014] The deposit is then cooled to room temperature and a fluorinated layer is deposited by spray coating, followed by a single sintering at 430°C.

[0015] In patent 3 (FR 2 871 038) the use of a PEEK auxiliary layer is mentioned, whereby a PAI resin and a fluorinated resin are deposited on a metal substrate and then covered with one or more layers of an anti-adhesion coating, the upper layers of which are free of PEEK.

[0016] The auxiliary layer is composed of a mixture of PAI, PEEK and PTFE such that the PTFE is present at 9-15% / w and the PAI resin is present at 4-5% / w.

[0017] In all cases the level of PEEK in the dry matter in the final fluorinated film is of the order of 0.12% to 1.1% / w, preferably 0.12% to 0.9% / w.

[0018] The PEEK powder has a particle size of D50 between 5 and 35 μm.

[0019] In all cases, the first coating layer contains a fluoride resin.

[0020] This liquid coating is deposited by spraying. Then a top layer of a fluorinated coating, which also contains one or more primers, is deposited by spraying. Sintering of all these layers is done in a single bake at 400-420°C.

[0021] The drawback of this application method is that the level of PEEK resin in the first layer is too low to achieve sufficient mechanical performance to have a scratch resistant coating.

[0022] Patent document 4 (WO 00 / 054896) mentions the use of a PEEK auxiliary layer consisting of at least 50% by weight of PEEK powder, free of fluorinated resin, such that the surface covered with PEEK constitutes 60% to 95% of the surface of the article.

[0023] This primer containing at least 50% PEEK may also contain blends with other pure or mixed heat stable resins such as polyphenylene sulfide (PPS), polyetherimide (PEI), polyimide (PI), polyetherketone (PEK), polyethersulfone (PES), polyamideimide (PAI), etc.

[0024] It may also contain a filler selected from silica, mica, or metal oxides of lamellar fillers. It does not contain fluoride resins.

[0025] The first heating is carried out at a high temperature of at least 260° C., preferably 340° C. or higher, in order to melt the PEEK.

[0026] The PEEK is in powder form with a particle size of 4 μm to 80 μm and a d50 of preferably 20 μm. The thickness of this auxiliary layer is comprised between 5 μm and 100 μm.

[0027] This liquid coating is deposited by spraying. Then a top layer of a fluorinated coating, or even a primer with a fluorinated topcoat, is deposited by spraying. Sintering of all these layers is done in two bakes, the second bake sintering the fluorinated coating at 400°C to 420°C.

[0028] Patent document 5 (US Pat. No. 6,596,380) describes a scratch-resistant fluorinated coating in which the first layer contains at least 50% by weight (preferably 60% to 95%) of PEEK, mixed with a heat-stable polymeric resin such as PPS, PEI, PI, PAI and mixtures thereof, and fillers such as metal oxides, silica, mica, etc., in the absence of fluorinated resins. This first layer has a thickness comprised between 5 and 100 μm.

[0029] PEEK is a powder with a particle size of 4 μm to 80 μm, with a d50 of approximately 20 μm. However, the process for obtaining such a coating necessarily involves a double firing / sintering at between 400-420°C.

[0030] definition The expression "cooking utensil" must be understood within the meaning of the present invention as an object for cooking. Cooking utensils within the meaning of the present invention include objects intended to be heated in order to cook or reheat the food carried by the cooking element or contained in the cooking element and the electric cooker.

[0031] The expression "object intended to be heated in order to cook or reheat the food carried by or contained in the cooking element" must be understood in the sense of the present invention as an object capable of being heated by an external heating system, such as a cooking oven, and of transferring the thermal energy provided by this external heating system to the material or food in contact with said object. Such an object may in particular be a frying pan, a saucepan, a sauté pan, a pan or pot for fondue or raclette, a stewpot, a wok, a sauté pan, a crepe maker, a cooking pot, a casserole dish, a cooking mould.

[0032] The expression "electric cooking appliance" must be understood in the sense of the present invention as a cooking object arranged to generate heat.

[0033] The expression "object configured to generate heat" must be understood in the sense of the present invention as a heating object having its own heating system.

[0034] Such an object may be, inter alia, a grill, a plancha, a cooker or bread machine tank, an electric crepe maker, an electric raclette machine, an electric fondue machine, an electric grill, an electric plancha, an electric cooker, a bread machine. [Prior art documents] [Patent documents]

[0035] [Patent Document 1] International Publication No. 2000 / 54895 [Patent Document 2] International Publication No. 2010 / 130954 [Patent Document 3] French Patent No. 2871038 [Patent Document 4] WO 00 / 054896 [Patent Document 5] U.S. Patent No. 6,596,380 Summary of the Invention [Problem to be solved by the invention]

[0036] The present invention describes the production of cookware that is resistant to cold and hot scratches while still being a non-stick article.

[0037] To overcome all these problems, the inventors have identified an optimal tie help-layer.

[0038] This formulation of the auxiliary layers also allows the coating under standard conditions with a limited number of layers and only one sintering process, thus making the process industrializable without additional investments.

[0039] The upper fluorinated layer is then applied by spraying, obtaining an excellent release of the coating. The presence of reinforcing fillers (alumina, silicon carbide, etc.) is also possible in the fluorinated layer. The resulting coating is produced in just one sintering condition at 420-430 °C. Excellent scratch resistance performance is obtained while keeping the cost of the coating at an industrially acceptable price.

[0040] This type of coating can significantly improve the scratch resistance of the coating at both room temperature and elevated temperatures (180° C.), while minimizing process costs and maintaining excellent release and adhesion properties. [Means for solving the problem]

[0041] The first subject of the invention relates to a bonding aid layer for an anti-adhesion coating on a metal substrate, a) 20% to 80% by weight of the total weight of the auxiliary layer of one or more polymers selected from the group consisting of polyaryletherketone (PAEK), polyethyleneimine (PEI), polyimide (PI), polyamideimide (PAI) and polybenzimidazole (PBI), with a weight ratio PAEK:(PEI+PI+PAI+PBI) of 1:1 to 15:1; b) at least 20% by weight, preferably at least 25% by weight, of the total weight of the auxiliary layer of one or more polymers selected from the group consisting of polyphenylene sulfide (PPS) and polyethersulfone (PES); c) a reinforcing inorganic filler, which is less than 40% by weight, preferably less than 30% by weight, of the total weight of the auxiliary layer, and preferably 5 to 25% by weight; d) 0 to 5% by weight of one or more fluorocarbon or acrylic resins based on the total weight of the auxiliary layer; e) optionally one or more pigments; The present invention is characterized by comprising:

[0042] A second subject of the invention relates to a cookware (1) comprising a metal support (2) having an inner surface (21) intended for cooking food, covered with a bonding aid layer (3) according to the invention and then with one or more layers of an anti-adhesive coating.

[0043] A third subject of the invention relates to a method for manufacturing a cooking utensil (1) comprising a metal support (2) having an inner surface (21) intended for cooking food, covered with a bonding aid layer (3) and then with one or more anti-adhesive coatings, i. providing a metal support (2) with two opposing faces; ii. shaping said support (2) to give it the shape of a cap (3) comprising a base (211) and a side wall (212) rising from the base (211) and thus defining an inner concave surface (21) and a convex outer surface (22) adapted to receive a food product, said step being carried out either before step iv) of producing said bonding aid layer (3) or after step v) of producing said anti-adhesive coating; iii. Optionally, treating the inner surface (21) of the support (2) to obtain a treated inner surface that favors adhesion of the auxiliary layer (3) onto the support (2); iv. depositing one or more continuous layers of a bonding aid layer (3) on said inner surface (21) of said support (2), said bonding aid layer (3) comprising: a) 20% to 80% by weight of the total weight of the auxiliary layer of one or more polymers selected from the group consisting of polyaryletherketone (PAEK), polyethyleneimine (PEI), polyimide (PI), polyamideimide (PAI) and polybenzimidazole (PBI), with a weight ratio PAEK:(PEI+PI+PAI+PBI) of 1:1 to 15:1; b) at least 20% by weight, preferably at least 25% by weight, of the total weight of the auxiliary layer of one or more polymers selected from the group consisting of polyphenylene sulfide (PPS) and polyethersulfone (PES); c) a reinforcing inorganic filler, which is less than 40% by weight, preferably less than 30% by weight, of the total weight of the auxiliary layer, and preferably 5 to 25% by weight; d) optionally one or more fluorocarbon or acrylic resins; e) optionally one or more pigments; and v. depositing one or more layers, preferably two layers, of an anti-adhesion coating based on a fluorocarbon resin on the bonding support layer (3) deposited in step (iv); Characterized by After deposition of the various layers, the overall T > 400 °C Only one sintering step (vi) The present invention is characterized by comprising: [Brief description of the drawings]

[0044] [Figure 1] Photo of the hot blade test. Three rotating metal tips on the inner coating of a cookware placed over a heat source. [Diagram 2] FIG. 1 is a diagram of a cooking utensil according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0045] Accordingly, the present invention is directed to bonding aid layers, anti-adhesive coatings, culinary articles, and methods of making such articles that overcome the shortcomings of the prior art.

[0046] The first subject of the invention relates to a bonding aid layer for an anti-adhesion coating on a metal substrate, a) 20% to 80% by weight of the total weight of the auxiliary layer of one or more polymers selected from the group consisting of polyaryletherketone (PAEK), polyethyleneimine (PEI), polyimide (PI), polyamideimide (PAI) and polybenzimidazole (PBI), with a weight ratio PAEK:(PEI+PI+PAI+PBI) of 1:1 to 15:1; b) at least 20% by weight, preferably at least 25% by weight, of the total weight of the auxiliary layer of one or more polymers selected from the group consisting of polyphenylene sulfide (PPS) and polyethersulfone (PES); c) a reinforcing inorganic filler, which is less than 40% by weight, preferably less than 30% by weight, of the total weight of the auxiliary layer, and preferably 5 to 25% by weight; d) 0 to 5% by weight, preferably 0 to 4% by weight, particularly preferably 0 to 3% by weight, of one or more fluorocarbon or acrylic resins, based on the total weight of the auxiliary layer; e) optionally one or more pigments; The present invention is characterized by comprising:

[0047] Advantageously, when the polymer a) represents 20-40% of the auxiliary layer according to the invention, the weight ratio PAEK:(PEI+PI+PAI+PBI) is comprised between 6:1 and 12:1. Advantageously, when the polymer a) represents 40 to 80% of the auxiliary layer according to the invention, the weight ratio PAEK:(PEI+PI+PAI+PBI) is comprised between 12:1 and 15:1.

[0048] Advantageously, the polymer b) represents between 25 and 40% by weight, preferably between 25 and 35% by weight, of the total weight of the auxiliary layer. The weight ratio between polymer a) and polymer b) is advantageously between 2:5 and 2:3, preferably between 1:2 and 1:3. In a particular embodiment, the bonding aid layer of the anti-adhesive coating on a metal support according to the invention is free of fluorocarbon or acrylic resins, in particular free of fluorocarbon resins, and advantageously free of PTFE. Advantageously, the pigment e) represents less than 30% by weight, preferably less than 20% by weight, of the total weight of the auxiliary layer.

[0049] Advantageously, the polyaryletherketone (PAEK) is selected from the group consisting of polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetheretherketoneketone (PEEKK) and polyetherketoneetherketoneketone (PEKEKK), particularly preferably PEEK. Advantageously, the polymer (a) is selected from the group consisting of polyaryletherketones (PAEK) and polyamideimides (PAI) and mixtures thereof. Particularly preferably, the (a) part is a mixture of PAEK and PAI polymers.

[0050] Advantageously, the polymer (a) is selected from the group consisting of polyetheretherketone (PEEK) and polyamideimide (PAI) and mixtures thereof. Particularly preferably, the (a) part is a mixture of PEEK and PAI polymers.

[0051] Advantageously, the polymer (b) is a polyethersulfone (PES).

[0052] In a preferred embodiment of the invention, parts (a) and (b) are a blend of PEEK, PAI and PES polymers.

[0053] The reinforcing inorganic fillers are preferably selected from the group consisting of metal oxides, carbides, nitrides, preferably selected from the group consisting of alumina, silicon carbide, and fumed silica.

[0054] The fluorocarbon resin is advantageously selected from the group consisting of polytetrafluoroethylene (PTFE), copolymers of tetrafluoroethylene and perfluoropropyl vinyl ether (PFA), copolymers of tetrafluoroethylene and hexafluoropropylene (FEP), and mixtures thereof, particularly preferably comprising PTFE.

[0055] The acrylic resin is advantageously selected from the group consisting of polymers resulting from emulsion polymerization of different monomers with other acrylic monomers.

[0056] The organic or inorganic pigments are selected from the group consisting of pigment powders known to those skilled in the art, for example titanium dioxide, carbon black, graphite, certain thermochromic pigments (such as bismuth oxide, vanadium oxide, etc.) or organic perylene pigments.

[0057] The bonding auxiliary layer of the anti-adhesion coating on a metal support according to the present invention may further comprise one or more solvents, which are preferably polar aprotic, preferably unlabeled, such as N-formylmorpholine (NFM), N-methylimidazole (NMI), N-butylpyrrolidone (NBP), dimethylsulfoxide (DMSO), or alcoholic solvents, such as propylene glycol (PPG), diethylene glycol.

[0058] The bonding aid layer of the anti-adhesion coating on a metal support according to the present invention may further comprise one or more surfactants.

[0059] The bonding aid layer of the anti-adhesive coating on a metal support according to the invention may further comprise one or more defoamers.

[0060] In a preferred embodiment of the invention, the bonding aid layer according to the invention is a mixture of PEEK, PAI, PES, PTFE, and optionally fillers, acrylics and pigments.

[0061] A second subject of the invention relates to the coating of metal substrates of cookware, comprising a bonding aid layer according to the invention covered by one or more layers of an anti-adhesive coating.

[0062] The anti-adhesive coating is advantageously based on a fluorocarbon resin. The adhesive coating preferably comprises two layers.

[0063] A third subject of the invention relates to a cooking utensil (1), comprising a metal support (2) having an inner surface (21) intended for cooking food, covered with a bonding aid layer (3) according to the invention and then with one or more layers of an anti-adhesive coating.

[0064] Advantageously, said metal support (2) is a monolayer support made of aluminium or an aluminium alloy, cast aluminium, stainless steel, cast steel or copper, or a multilayer support comprising, from the outside to the inside, layers of ferritic stainless steel / aluminium / austenitic stainless steel or stainless steel / aluminium / copper / aluminium / austenitic stainless steel, or a cast aluminium cap backed by an outer substrate of stainless steel, aluminium or an aluminium alloy.

[0065] The metal support (2) (disc or moulding) to which the bonding aid layer according to the invention is applied may have a roughness obtained by sand blasting, shot blasting, stamping, brushing or chemical attack. The thickness of the bonding auxiliary layer (3) is advantageously comprised between 10 and 100 μm, preferably between 20 μm and 80 μm, and more preferably between 30 and 60 μm.

[0066] The cookware (1) according to the present invention is preferably a frying pan or a pot.

[0067] A third subject of the invention relates to a method for manufacturing a cooking utensil (1) comprising a metal support (2) having an inner surface (21) intended for cooking food, covered with a bonding aid layer (3) and then with one or more layers of an anti-adhesive coating, i. providing a metal support (2) with two opposing faces; ii. shaping said support (2) to give it the shape of a cap (3) comprising a base (211) and a side wall (212) rising from the base (211) and thus defining an inner concave surface (21) and a convex outer surface (22) adapted to receive a food product, said step being carried out either before step iv) of producing said bonding aid layer (3) or after step v) of producing said anti-adhesive coating; iii. Optionally, treating the inner surface (21) of the support (2) to obtain a treated inner surface that favors adhesion of the auxiliary layer (3) onto the support (2); iv. depositing one or more continuous layers of a bonding aid layer (3) on said inner surface (21) of said support (2), said bonding aid layer (3) comprising: a) 20% to 80% by weight of the total weight of the auxiliary layer of one or more polymers selected from the group consisting of polyaryletherketone (PAEK), polyethyleneimine (PEI), polyimide (PI), polyamideimide (PAI) and polybenzimidazole (PBI), with a weight ratio PAEK:(PEI+PI+PAI+PBI) of 1:1 to 15:1; b) at least 20% by weight, preferably at least 25% by weight, of the total weight of the auxiliary layer of one or more polymers selected from the group consisting of polyphenylene sulfide (PPS) and polyethersulfone (PES); c) a reinforcing inorganic filler, which is less than 40% by weight, preferably less than 30% by weight, of the total weight of the auxiliary layer, and preferably 5 to 25% by weight; d) optionally one or more fluorocarbon or acrylic resins; e) optionally one or more pigments; and v. depositing one or more layers, preferably two layers, of an anti-adhesion coating based on a fluorocarbon resin on the bonding support layer (3) deposited in step (iv); Characterized by After deposition of the various layers, the overall T > 400 °C Only one sintering step (vi) The present invention is characterized by comprising:

[0068] The method for producing a cookware (1) comprising a metal support (2) having an inner surface (21) intended for cooking food, covered with a bonding aid layer (3) and then with one or more layers of an anti-adhesive coating, does not include two sintering steps or two cooking steps. The method according to the invention does not include three sintering steps or three cooking steps. The method according to the invention comprises only one heating step by sintering.

[0069] In a preferred embodiment, the bonding aid layer (3) deposited in step iv comprises 0-5%, preferably 0-4%, particularly preferably 0-3% of one or more fluorocarbon or acrylic resins.

[0070] In certain embodiments, the bonding aid layer (3) deposited in step iv does not include any fluorocarbon resin, in particular PTFE.

[0071] Advantageously, the metal support (2) of step i is disc-shaped.

[0072] Advantageously, the bonding aid layer (3) is deposited by spraying, coating, screen printing or by roller.

[0073] Advantageously, the sintering temperature is comprised between 400°C and 440°C. EXAMPLES

[0074] 1) Performance tests carried out on the coating Mechanical durability evaluation test - scratch resistance The excellent mechanical performance of this coating is evaluated using a hot blade test.

[0075] This test method evaluates the scratch resistance of coatings using a mobility system consisting of three hard tips (ballpoint pens). This test, also known as the "Tiger Paw", induces a rotation around its axis, tracing an epicyclic movement on the coated surface. The test is carried out under heat. The degradation of the coating (appearance of spots on the metal, scratches, peeling of the coating) is visually evaluated after different time cycles.

[0076] A carbonized milk release test is performed after each of the previous cycles.

[0077] In this test, three output data can be finally evaluated. - Delamination of the fluorinated coating on the metal surface or on the fluorinated interlayer after the test time (duration). - Appearance of scratches on metal: scratches on metal after test time (duration). - Peel loss (AA=0) over the test time (duration).

[0078] Corrosion resistance evaluation of semi-finished or primer layers on shot-blasted aluminum substrates There will be an exam for point 3 above.

[0079] The corrosion resistance of anti-adhesion coatings on sandblasted aluminum substrates is evaluated by assessing their resistance to diffusion of salts into the corroded metal substrate.

[0080] To this end, we proceeded as follows. -Substrates coated with a fluorinated coating were immersed for 20 hours in boiling saline solution containing 10% by weight of sodium chloride. The protocol for this test is defined in the AFNOR NF D21-511 $3.3.5 standard. - At the end of each dip, a final visual inspection of the coating's appearance is carried out, which consists in noting the presence or absence of traces of corrosion (visual observation with the naked eye or binocular magnifier). In practice, this involves detecting the possible presence of traces, such as air bubbles with enlarged areas, white marks under the coating, etc. -After this observation, a grid test is carried out according to the ISO 2409 standard.

[0081] Evaluating the adhesion of semi-finish or primer layers on smooth aluminum substrates There is a standardized grid test according to the ISO 2409 standard, followed by immersion of the coated article for 18 hours (consisting of 3 cycles of 3 hours in boiling water alternating with 3 cycles of 3 hours in oil at 200°C), after which it is observed whether the anti-adhesive coating shows any peeling.

[0082] The rating is as follows: no delaminated squares earn a rating of 100 (excellent adhesion). In the event of delamination, the recorded value is equal to a rating of 100 reduced by the number of delaminated squares.

[0083] 2) Exemplary embodiments: support - The sandblasted or shot blasted aluminum support then undergoes an appropriate surface treatment to remove organic contaminants.

[0084] raw materials -Heterocyclic polymer resins: Polyamide-imide (PAI) resin with 29% dry extract in N-butylpyrrolidone (NBP) Resin in powder form: PolyAcide amic at 90% dry extract in N-methylpyrrolidone (NMP / water), reference from Solvay, grade TORLON AI10LS Resin in solvent: 9% polybenzimidazole (PBI) in dimethylacetamide (DMAc) -Other aromatic polymer resins: Polyetheretherketone (PEEK) powder resin, Vicote 704 from VICTREX, a polymer powder with a d50 of 10μm PEKK powder resin, KEPSTAN 7002 PT from ArKema, d50 20μm PEKK powder resin, KEPSTAN 6002 PT from Arkema, d50 of 50μm Polyethersulfone (PES) resin powder, finely divided grade from SOLVAY, polymer powder with d50 of 40μm -Fluorinated polymer resin (UltraTurrax, 20000 rpm, pre-dispersed at 20% in PPG): PTFE powder from 3M / DYNEON: TF9207Z, -FEP powder made by 3M / DYNEON: 6233PZ. - Non-indicated polar aprotic solvents (i.e. non-toxic within the meaning of the present invention): N-Formylmorpholine (NFM) N-Methylimidazole (NMI) N-Butylpyrrolidone (NBP) -Alcohol solvent Propylene glycol: PPG Diethylene glycol: Butyl diglycol -Surfactants and defoamers Tego foamex K7 from Evonik ·Genapol X08 from Clariant -Reinforcing fillers: Alumina, grade CAHP-F240 (particle size at d50: 50 μm) Silicon carbide, grades SIKA 400, SIKA 320 · Fumed Silica ·MICA MILL 200 / 325 -Pigments Black 100, Blue CM13, Perylene brick red (wear indicator) Titanium ·talc Graphite -Acrylic resin: Modarez PW336: 30% acrylic polymer solution in water phase Rohagit SD 15: 30% acrylic polymer solution in water phase

[0085] Example 1: A continuous layer SCD1 (SCD = bonding auxiliary layer) of Example 1 described below on a molded aluminum disc (diameter 30 cm), previously degreased and polished to obtain a roughness (Ra) of 4 to 7 μm.

[0086] Preparation of aqueous semi-finished composition SF1 based on a heterocyclic polymer with an amine and a non-indicated polar aprotic solvent.

[0087] An aqueous semi-finished composition SF1 was prepared containing the following compounds, the respective amounts of which are indicated below:

[0088] [Table 1]

[0089] The introduction of the PAI involves a step of transferring the polyamide-amino acid salt through the aqueous phase, which is carried out in a Discontimill® brand ball mill at room temperature in the presence of an amine.

[0090] The characteristics of the aqueous composition SF1 thus obtained are as follows: -Theoretical dry extract: 9.5% - Dry extract measured in the composition: 9.3%

[0091] Principle of operation of jar mill (mechanical grinding) principle Ball milling consists of placing the sample to be ground and the so-called mill balls in a jar and rotating the jar around its axis at a certain speed. The rotation of the jar is generally carried out using a roller machine. The sample can be ground in dry form or dispersed in a suitable solvent (e.g. in water, alcohol or solvent). The dispersion can also contain certain adjuvants (such as dispersants or antifoaming agents).

[0092] Preparation of semi-finished composition SF2 carried out in a ball mill for 20 minutes to obtain a ground paste, referenced SF2 below.

[0093] The alcohol (PPG) and PTFE powder are pre-dispersed at very high speed using the ultra-turax system before being incorporated into the mixture as follows:

[0094] [Table 2]

[0095] Composition of SCD1 Sublayer in Example 1 The last step is carried out in a Rayneri type disperser to obtain the following bonding aid layer:

[0096] [Table 3]

[0097] The auxiliary layer SCD1 of Example 1 thus obtained had the following characteristics. - The final weight ratio of the polymer resin mixture is: PEEK / PAI / PES / filler / PTFE: 19 / 3 / 23 / 25 / 30 -Theoretical dry extract: 40.7% - Viscosity measured with AFNOR CA6 cup: 50 seconds

[0098] The thickness of this layer SCD1 in the first embodiment is comprised between 50 μm and 100 μm, preferably between 40 μm and 60 μm.

[0099] The above mentioned substrate and successive auxiliary layers are coated with a multi-layer anti-adhesion coating consisting of an intermediate coat (6-8 μm) and a finish (14-18 μm) that are dried at 100 ° C for 4 minutes. The whole is finally heated at 430 ° C for 11 minutes, i.e. the process involves only one sintering step at T ° C > 400 ° C after the deposition of the various layers. The composition is as follows:

[0100] [Table 4]

[0101] [Table 5]

[0102] Example 2: On a molded aluminum disk (diameter 30 cm), previously degreased and polished to obtain a roughness (Ra) of 4 to 7 μm, a successive layer SCD2 of Example 2 is deposited as described below.

[0103] Principle of operation of jar mill (mechanical grinding) principle Ball milling consists of placing the sample to be ground and the so-called mill balls in a jar and rotating the jar around its axis at a certain speed. The rotation of the jar is generally carried out using a roller machine. The sample can be ground in dry form or dispersed in a suitable solvent (e.g. in water, alcohol or solvent). The dispersion can also contain certain adjuvants (such as dispersants or antifoaming agents).

[0104] Preparation of semi-finished composition SF3 carried out in a ball mill for 20 minutes to obtain a ground paste, referenced SF3 below.

[0105] [Table 6]

[0106] Composition of auxiliary layer SCD2 in Example 2 The last step is carried out in a Rayneri type disperser to obtain the following bonding aid layer:

[0107] [Table 7]

[0108] The properties of the SCD2 auxiliary layer of Example 2 thus obtained are as follows: - The final weight ratio of the polymer resin mixture is: PEEK / PAI / PES / filler / acrylic resin / pigment: 19 / 3 / 23 / 30 / 5 / 20 -Theoretical dry extract: 41.1% - Viscosity measured with AFNOR CA6 cup: 45 seconds

[0109] The thickness of this layer SCD2 in the second embodiment is comprised between 50 μm and 100 μm, preferably between 40 μm and 60 μm. The above mentioned substrate and successive auxiliary layers are coated with a multi-layer anti-adhesion coating consisting of an intermediate coat (6-8 μm) and a finish (14-18 μm) that are dried for 4 min at 100° C. The whole is finally heated for 11 min at 430° C., i.e. the method involves only one sintering step at T° C. >400° C. after the deposition of the various layers.

[0110] The midcoat and finish formulas are shown above.

[0111] Example 3: On a molded aluminum disk (diameter 30 cm), previously degreased and polished to obtain a roughness (Ra) of 4-7 μm, a successive layer SCD3 of Example 3 is deposited as described below.

[0112] Principle of operation of jar mill (mechanical grinding) principle Ball milling consists of placing the sample to be ground and the so-called mill balls in a jar and rotating the jar around its axis at a certain speed. The rotation of the jar is generally carried out using a roller machine. The sample can be ground in dry form or dispersed in a suitable solvent (e.g. in water, alcohol or solvent). The dispersion can also contain certain adjuvants (such as dispersants or antifoaming agents).

[0113] Preparation of semi-finished composition SF4 carried out in a ball mill for 20 minutes to obtain a ground paste, referenced SF4 below.

[0114] The alcohol (PPG) and PTFE powders are pre-dispersed at very high speed using the ultra-turax system before being incorporated into the mixture as follows:

[0115] [Table 8]

[0116] Composition of auxiliary layer SCD3 of Example 3 The last step is carried out in a Rayneri type disperser to obtain the following bonding aid layer:

[0117] [Table 9]

[0118] The auxiliary layer SCD3 of Example 3 thus obtained had the following characteristics: The final weight ratio of the polymer resin mixture is: PEEK / PAI / PES / filler / PTFE / pigment: 17 / 3 / 25 / 15 / 30 / 10: -Theoretical dry extract: 41.1% - Viscosity measured with AFNOR CA6 cup: 2.10 minutes

[0119] The thickness of this layer SCD3 in the third embodiment is comprised between 50 μm and 100 μm, preferably between 40 μm and 60 μm.

[0120] The above mentioned substrate and successive auxiliary layers are coated with a multi-layer anti-adhesion coating consisting of an intermediate coat (6-8 μm) and a finish (14-18 μm) that are dried for 4 min at 100° C. The whole is finally heated for 11 min at 430° C., i.e. the method involves only one sintering step at T° C. >400° C. after the deposition of the various layers.

[0121] The midcoat and finish formulas are shown above.

[0122] Example 4: On a molded aluminum disk (diameter 30 cm), previously degreased and polished to obtain a roughness (Ra) of 4-7 µm, a successive layer SCD4 of Example 4 is deposited as described below.

[0123] Principle of operation of jar mill (mechanical grinding) principle Ball milling consists of placing the sample to be ground and the so-called mill balls in a jar and rotating the jar around its axis at a certain speed. The rotation of the jar is generally carried out using a roller machine. The sample can be ground in dry form or dispersed in a suitable solvent (e.g. in water, alcohol or solvent). The dispersion can also contain certain adjuvants (such as dispersants or antifoaming agents).

[0124] Preparation of semi-finished composition SF5 carried out in a ball mill for 20 minutes to obtain a ground paste, referenced SF5 below.

[0125] [Table 10]

[0126] Composition of auxiliary layer SCD4 of Example 4 The last step is carried out in a Rayneri type disperser to obtain the following bonding aid layer:

[0127] [Table 11]

[0128] The properties of the thus obtained auxiliary layer SCD4 of Example 4 are as follows: - The final weight ratio of the polymer resin mixture is: PEEK / PAI / PES / filler / acrylic resin / pigment: 17 / 3 / 25 / 30 / 5 / 20 -Theoretical dry extract: 42.4% - Viscosity measured with AFNOR CA6 cup: 55 seconds

[0129] The thickness of this layer SCD4 in the fourth embodiment is comprised between 50 μm and 100 μm, and preferably between 40 μm and 60 μm. The above mentioned substrate and successive auxiliary layers are coated with a multi-layer anti-adhesion coating consisting of an intermediate coat (6-8 μm) and a finish (14-18 μm) that are dried for 4 min at 100° C. The whole is finally heated for 11 min at 430° C., i.e. the method involves only one sintering step at T° C. >400° C. after the deposition of the various layers.

[0130] The midcoat and finish formulas are shown above.

[0131] Example 5: On a molded aluminum disk (diameter 30 cm), previously degreased and polished to obtain a roughness (Ra) of 4-7 μm, a successive layer SCD5 of Example 5 is deposited as described below.

[0132] Principle of operation of jar mill (mechanical grinding) principle Ball milling consists of placing the sample to be ground and the so-called mill balls in a jar and rotating the jar around its axis at a certain speed. The rotation of the jar is generally carried out using a roller machine. The sample can be ground in dry form or dispersed in a suitable solvent (e.g. in water, alcohol or solvent). The dispersion can also contain certain adjuvants (such as dispersants or antifoaming agents).

[0133] Preparation of semi-finished composition SF6 carried out in a ball mill for 20 minutes to obtain a ground paste, referenced SF6 below.

[0134] The alcohol (PPG) and PTFE powder and FEP are pre-dispersed at very high speed using the ultra-turax system before being incorporated into the mixture as follows:

[0135] [Table 12]

[0136] Composition of auxiliary layer SCD5 of Example 5 The last step is carried out in a Rayneri type disperser to obtain the following bonding aid layer:

[0137] [Table 13]

[0138] The properties of the SCD5 auxiliary layer of Example 5 thus obtained are as follows: - The final weight ratio of the polymer resin mixture is: PEEK / PAI / PES / filler / PTFE / FEP: 19 / 3 / 23 / 25 / 25 / 5: - Theoretical dry extract: 41.0% - Viscosity measured with AFNOR CA6 cup: 1 min 50 sec

[0139] The thickness of this layer SCD5 in the fifth embodiment is comprised between 50 μm and 100 μm, preferably between 40 μm and 60 μm.

[0140] The above mentioned substrate and successive auxiliary layers are coated with a multi-layer anti-adhesion coating consisting of an intermediate coat (6-8 μm) and a finish (14-18 μm) that are dried for 4 min at 100° C. The whole is finally heated for 11 min at 430° C., i.e. the method involves only one sintering step at T° C. >400° C. after the deposition of the various layers.

[0141] The midcoat and finish formulas are shown above.

[0142] Example 6: On a molded aluminum disk (diameter 30 cm), previously degreased and polished to obtain a roughness (Ra) of 4-7 μm, a successive layer SCD6 of Example 6 is deposited as described below.

[0143] Preparation of semi-finished composition SF7 carried out in a ball mill for 20 minutes to obtain a ground paste, see SF7 below.

[0144] [Table 14]

[0145] Composition of auxiliary layer SCD6 of Example 6 The last step is carried out in a Rayneri type disperser to obtain the following hard sublayer:

[0146] [Table 15]

[0147] The properties of the thus obtained auxiliary layer SCD6 of Example 6 are as follows: The final weight ratio of the polymer resin mixture is: PEEK / PAI / PES / :75 / 5 / 20 - Theoretical dry extract: 38.5% - Viscosity measured with AFNOR CA6 cup: 1 minute 40 seconds

[0148] The thickness of this layer SCD6 in the sixth embodiment is comprised between 50 μm and 100 μm, preferably between 40 μm and 60 μm.

[0149] The above mentioned substrate and successive auxiliary layers are coated with a multi-layer anti-adhesion coating consisting of an intermediate coat (6-8 μm) and a finish (14-18 μm) that are dried for 4 min at 100° C. The whole is finally heated for 11 min at 430° C., i.e. the method involves only one sintering step at T° C. >400° C. after the deposition of the various layers.

[0150] The midcoat and finish formulas are shown above.

[0151] Example 7: On a molded aluminum disk (diameter 30 cm), previously degreased and polished to obtain a roughness (Ra) of 4 to 7 μm, a successive layer SCD7 of Example 7 is deposited as described below.

[0152] Preparation of semi-finished composition SF8 carried out in a ball mill for 20 minutes to obtain a ground paste, referenced SF8 below.

[0153] The alcohol (PPG) and PTFE powders are pre-dispersed at very high speed using the ultra-turax system before being incorporated into the mixture as follows:

[0154] [Table 16]

[0155] Composition of auxiliary layer SCD7 of Example 7 The last step is carried out in a Rayneri type disperser to obtain the following hard sublayer:

[0156] [Table 17]

[0157] The properties of the thus obtained auxiliary layer SCD7 of Example 7 are as follows: The final weight ratios of the polymer resin mixture are: PEEK / PAI / PES / filler / PTFE / pigment: 42 / 3 / 20 / 10 / 20 / 5 -Theoretical dry extract: 40.3% - Viscosity measured with AFNOR CA6 cup: 2 minutes 40 seconds

[0158] The thickness of this layer SCD7 in the seventh embodiment is comprised between 50 μm and 100 μm, preferably between 40 μm and 60 μm.

[0159] The above mentioned substrate and successive auxiliary layers are coated with a multi-layer anti-adhesion coating consisting of an intermediate coat (6-8 μm) and a finish (14-18 μm) that are dried for 4 min at 100° C. The whole is finally heated for 11 min at 430° C., i.e. the method involves only one sintering step at T° C. >400° C. after the deposition of the various layers.

[0160] The midcoat and finish formulas are shown above.

[0161] Counterexample 1: On a molded aluminum disc (30 cm diameter), previously degreased and polished to obtain a roughness (Ra) of 4-7 µm, deposit a successive layer SCD8 of counterexample 1, as described below.

[0162] Preparation of semi-finished composition SF9 carried out in a ball mill for 20 minutes to obtain a ground paste, see SF9 below.

[0163] The alcohol (PPG) and PTFE powder are pre-dispersed at very high speed using the ultra-turax system before being incorporated into the mixture as follows:

[0164] [Table 18]

[0165] The formulation of the sublayer SCD8 of counter example 1 is carried out in a Rayneri type disperser to obtain the following hard sublayer:

[0166] [Table 19]

[0167] The characteristics of the auxiliary layer SCD8 of counter example 1 thus obtained are as follows: The final weight ratios of the polymer resin mixture are: PEEK / PAI / filler / PTFE:42 / 3 / 20 / 35 -Theoretical dry extract: 41.2% - Viscosity measured with AFNOR CA6 cup: 1 min 0 sec

[0168] The thickness of this layer SCD8 in counter example 1 is comprised between 50 μm and 100 μm, preferably between 40 μm and 60 μm.

[0169] The above mentioned substrate and the successive auxiliary layers are coated with a multi-layer anti-adhesion coating consisting of an intermediate coat (6-8 μm) and a finish coat (14-18 μm) which are dried for 4 minutes at 100° C. The whole is finally heated at 430° C. for 11 minutes.

[0170] The midcoat and finish formulas are shown above.

[0171] Counterexample 2: On a molded aluminum disk (diameter 30 cm), previously degreased and polished to obtain a roughness (Ra) of 4-7 μm, a continuous layer SCD8 of the counter example 1 described above is deposited.

[0172] The thickness of this layer SCD8 in counter example 1 is comprised between 50 μm and 100 μm, preferably between 40 μm and 60 μm.

[0173] This sublayer is heated to 430°C for 11 minutes and then cooled to 25-30°C for coating with the following fluorinated layers: Anti-adhesion coating consisting of intermediate coat (6-8μm) and finish coat (14-18μm) dried at 100°C for 4 minutes. Finally the whole is heated at 430°C for 11 minutes.

[0174] The midcoat and finish formulas are shown above. The finished coating is subjected to two sintering cycles at 430°C.

[0175] Counterexample 3:

[0176] On a molded aluminum disk (diameter 30 cm), previously degreased and polished to obtain a roughness (Ra) of 4-7 µm, a successive layer SCD9 of the counterexample 3 described below is deposited.

[0177] Preparation of semi-finished composition SF10 carried out in a ball mill for 20 minutes to obtain a ground paste, referenced SF10 below.

[0178] [Table 20]

[0179] The formulation of the sublayer SCD9 of counter example 3 is carried out in a Rayneri type disperser to obtain the following hard sublayer:

[0180] [Table 21]

[0181] The characteristics of the auxiliary layer SCD9 of the counter example 3 thus obtained are as follows: The final weight ratios of the polymer resin mixture are as follows: -PEEK / PAI / filler / acrylic resin / pigment: 42 / 3 / 30 / 5 / 20 -Theoretical dry extract: 41.0% - Viscosity measured with AFNOR CA6 cup: 55 seconds

[0182] The layer thickness of this SCD 9 in counter example 3 is comprised between 50 μm and 100 μm, preferably between 40 μm and 60 μm.

[0183] The above mentioned substrate and the successive auxiliary layers are coated with a multi-layer anti-adhesion coating consisting of an intermediate coat (6-8 μm) and a finish coat (14-18 μm) which are dried for 4 minutes at 100° C. The whole is finally heated at 430° C. for 11 minutes.

[0184] The midcoat and finish formulas are shown above.

[0185] Counterexample 4: A continuous layer SCD10 of counter example 4 described below is deposited on a molded aluminum disk (diameter 30 cm), previously degreased and polished to obtain a roughness (Ra) of 4-7 μm.

[0186] Preparation of semi-finished composition SF11 carried out in a ball mill for 20 minutes to obtain a ground paste, see SF11 below.

[0187] [Table 22]

[0188] The formulation of the sublayer SCD10 of counter example 4 is carried out in a Rayneri type disperser to obtain the following hard sublayer:

[0189] [Table 23]

[0190] The characteristics of the auxiliary layer SCD10 of the counter example 4 thus obtained are as follows: The final weight ratios of the polymer resin mixture are: PEEK / filler / acrylic resin / pigment: 45 / 30 / 5 / 20 -Theoretical dry extract: 51.9% - Viscosity measured with AFNOR CA6 cup: 3 minutes 30 seconds

[0191] The thickness of this layer SCD8 in counter example 4 is comprised between 50 μm and 100 μm, preferably between 40 μm and 60 μm.

[0192] The above mentioned substrate and the successive auxiliary layers are coated with a multi-layer anti-adhesion coating consisting of an intermediate coat (6-8 μm) and a finish coat (14-18 μm) which are dried for 4 minutes at 100° C. The whole is finally heated at 430° C. for 11 minutes.

[0193] The midcoat and finish formulas are shown above.

[0194] Counterexample 6: On a molded aluminum disk (diameter 30 cm), previously degreased and polished to obtain a roughness (Ra) of 4-7 µm, a successive layer SCD11 of the counterexample 6 described below is deposited.

[0195] Preparation of semi-finished composition SF12 carried out in a ball mill for 20 minutes to obtain a ground paste, referenced SF12 below.

[0196] [Table 24]

[0197] The compounding of the sublayer SCD11 of counter example 6 is carried out in a Rayneri type disperser to obtain the following hard sublayer:

[0198] [Table 25]

[0199] The characteristics of the auxiliary layer SCD11 of the counter example 6 thus obtained are as follows. The final weight ratios of the polymer resin mixture are: PEEK / PAI / PES / filler / acrylic resin / pigment: 5 / 3 / 37 / 30 / 5 / 20 -Theoretical dry extract: 41.3% - Viscosity measured with AFNOR CA6 cup: 45 seconds

[0200] The thickness of this layer SCD11 in counter example 6 is comprised between 50 μm and 100 μm, preferably between 40 μm and 60 μm.

[0201] The above mentioned substrate and the successive auxiliary layers are coated with a multi-layer anti-adhesion coating consisting of an intermediate coat (6-8 μm) and a finish coat (14-18 μm) which are dried for 4 minutes at 100° C. The whole is finally heated at 430° C. for 11 minutes.

[0202] The midcoat and finish formulas are shown above.

[0203] 3) Benefits offered The following table shows: -Fluoride resin -Filling agent -Acrylic resin -Pigments The results clearly show the advantages brought about by the use of an auxiliary layer based on a blend of heat-stable polymer resins based on PEEK / PES / PAI, with or without the presence of

[0204] The complete coating anti-adhesion with an upper layer based on a fluorinated resin is good. The appearance of scratches, highlighted by the test used (hot blade at 180°C), is significantly postponed or even non-existent for configurations in which the thickness of the auxiliary layer is comprised between 50 μm and 100 μm, preferably between 40 μm and 60 μm.

[0205] The coating can be achieved in just one sintering step at 400-430 °C for 11 minutes while maintaining excellent adhesion to the metal substrate and interlayer adhesion.

[0206]

Table 26

Claims

1. A bonding aid layer of an anti-adhesion coating on a metal substrate, comprising: a) 20% to 80% by weight of the total weight of the auxiliary layer of one or more polymers selected from the group consisting of polyaryletherketone (PAEK), polyethyleneimine (PEI), polyimide (PI), polyamideimide (PAI) and polybenzimidazole (PBI), having a weight ratio PAEK:(PEI+PI+PAI+PBI) of 1:1 to 15:1; b) at least 20% by weight, preferably at least 25% by weight, of the total weight of the auxiliary layer of one or more polymers selected from the group consisting of polyphenylene sulfide (PPS) and polyether sulfone (PES); c) reinforcing inorganic fillers, which constitute less than 40% by weight, preferably less than 30% by weight, of the total weight of said auxiliary layer, and preferably between 5 and 25% by weight; d) 0 to 5% by weight of the total weight of the auxiliary layer of at least one fluorocarbon or acrylic resin; e) optionally one or more pigments; 1. A bonding aid layer for an anti-adhesion coating on a metal substrate, comprising:

2. 2. The bonding aid layer of an anti-adhesion coating on a metal support according to claim 1, wherein the polyaryletherketone (PAEK) is selected from the group consisting of polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetheretherketoneketone (PEEKK) and polyetherketoneetherketoneketone (PEKEKK).

3. 3. The bonding aid layer of an anti-adhesion coating on a metal substrate according to claim 1, wherein the polymer is selected from the group consisting of polyetheretherketone (PEEK) and polyamideimide (PAI).

4. 3. The bonding aid layer of an anti-adhesion coating on a metal substrate according to claim 1, wherein the polymer is polyethersulfone (PES).

5. 2. The bonding aid layer of an anti-adhesion coating on a metal support according to claim 1, wherein the parts (a) and (b) are a mixture of PEEK, PAI and PES polymers.

6. 2. The bonding aid layer of an anti-adhesion coating on a metal support according to claim 1, characterized in that the reinforcing inorganic filler is selected from the group consisting of metal oxides, carbides, nitrides, preferably alumina, silicone carbide or fumed silica.

7. 2. The bonding-aid layer of an anti-adhesion coating on a metal support according to claim 1, characterized in that the fluorocarbon resin is selected from the group consisting of polytetrafluoroethylene (PTFE), a copolymer of tetrafluoroethylene and perfluoropropyl vinyl ether (PFA), a copolymer of tetrafluoroethylene and hexafluoropropylene (FEP), and mixtures thereof.

8. 2. The bonding auxiliary layer of an anti-adhesion coating on a metal support according to claim 1, characterized in that the pigment is selected from the group consisting of titanium dioxide, carbon black, graphite, certain thermochromic pigments such as bismuth oxide, vanadium oxide, etc., or organic perylene pigments.

9. 2. The bonding aid layer of an anti-adhesion coating on a metal support according to claim 1, further comprising one or more solvents, said solvents being preferably aprotic and preferably non-transparent.

10. The bonding aid layer of an anti-adhesion coating on a metal substrate according to claim 1 , further comprising one or more surfactants.

11. The bonding aid layer of an anti-adhesion coating on a metal substrate according to claim 1, further comprising one or more anti-foaming agents.

12. A cooking utensil (1) comprising a metal support (2) having an inner surface (21) intended for cooking food, which is covered with a bonding aid layer (3) according to claim 1 and then with one or more layers of an anti-stick coating.

13. 13. The cooking utensil (1) according to claim 12, characterized in that the metal support (2) is a single layer support made of aluminum or an aluminum alloy, cast aluminum, stainless steel, cast steel or copper, or a multilayer support comprising, from the outside to the inside, layers of ferritic stainless steel / aluminum / austenitic stainless steel, or stainless steel / aluminum / copper / aluminum / austenitic stainless steel, or a cast aluminum cap, aluminum or an aluminum alloy backed on an outer substrate of stainless steel.

14. A cooking utensil (1) according to claim 12, characterized in that the thickness of the bonding aid layer (3) is comprised between 10 μm and 100 μm, preferably between 20 μm and 80 μm, preferably between 30 μm and 60 μm.

15. A cooking utensil (1) according to claim 12, characterized in that it is a frying pan or a saucepan.

16. 1. A method for manufacturing a cooking utensil (1) comprising a metal support (2) having an inner surface (21) intended for cooking food, covered with a bonding aid layer (3) and then with one or more layers of an anti-stick coating, comprising: i. Providing a metal support (2) having two opposite faces; ii. Moulding the support (2) to give it the shape of a cap having a bottom surface (211) and side walls (212) rising from said bottom surface (211), thus defining an inner concave surface (21) and an outer convex surface (22) adapted to receive food, which is carried out either before step iv) of producing the bonding aid layer (3) or after step v) of producing the anti-adhesive coating, iii. Optionally, treating the inner surface (21) of said support (2) to obtain a treated inner surface that favors adhesion of the auxiliary layer (3) onto said support (2); iv. depositing one or more continuous layers of the bonding auxiliary layer (3) on the inner surface (21) or the bottom surface (211) of the support (2), wherein the auxiliary layer (3) comprises: a) 20% to 80% by weight of the total weight of the auxiliary layer of one or more polymers selected from the group consisting of polyaryletherketone (PAEK), polyethyleneimine (PEI), polyimide (PI), polyamideimide (PAI) and polybenzimidazole (PBI), having a weight ratio PAEK:(PEI+PI+PAI+PBI) of 1:1 to 15:1; b) at least 20% by weight, preferably at least 25% by weight, of the total weight of the auxiliary layer of one or more polymers selected from the group consisting of polyphenylene sulfide (PPS) and polyethersulfone (PES); c) reinforcing inorganic fillers, which constitute less than 40% by weight, preferably less than 30% by weight, of the total weight of said auxiliary layer, and preferably between 5 and 25% by weight; d) optionally one or more fluorocarbon or acrylic resins; e) optionally one or more pigments; and v. depositing one or more layers, preferably two layers, of an anti-adhesion coating based on a fluorocarbon resin on the bonding aid layer (3) deposited in step (iv); is characterized by A method characterized in that it comprises, after the deposition of the various layers, only one sintering step (vi) at a total T°C > 400°C.

17. 17. The method according to claim 16, characterized in that the adhesion aid layer (3) is deposited by spraying, coating, screen printing or roller.

18. The method according to claim 16, characterized in that the sintering temperature is comprised between 400°C and 440°C.

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