Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
  • C09D5/24—Electrically-conducting paints
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
  • C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
  • C23C18/31—Coating with metals
• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47J—KITCHEN EQUIPMENT; COFFEE MILLS; SPICE MILLS; APPARATUS FOR MAKING BEVERAGES
  • A47J36/00—Parts, details or accessories of cooking-vessels
  • A47J36/02—Selection of specific materials, e.g. heavy bottoms with copper inlay or with insulating inlay
• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47J—KITCHEN EQUIPMENT; COFFEE MILLS; SPICE MILLS; APPARATUS FOR MAKING BEVERAGES
  • A47J36/00—Parts, details or accessories of cooking-vessels
  • A47J36/02—Selection of specific materials, e.g. heavy bottoms with copper inlay or with insulating inlay
  • A47J36/025—Vessels with non-stick features, e.g. coatings
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D1/00—Processes for applying liquids or other fluent materials
  • B05D1/02—Processes for applying liquids or other fluent materials performed by spraying
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
  • B05D3/02—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by baking
  • B05D3/0254—After-treatment
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D5/00—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures
  • B05D5/12—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures to obtain a coating with specific electrical properties
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
  • B05D7/14—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
  • C08G77/48—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule in which at least two but not all the silicon atoms are connected by linkages other than oxygen atoms
  • C08G77/56—Boron-containing linkages
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/02—Elements
  • C08K3/04—Carbon
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/02—Elements
  • C08K3/08—Metals
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D1/00—Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D183/00—Coating compositions based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon, with or without sulfur, nitrogen, oxygen, or carbon only; Coating compositions based on derivatives of such polymers
  • C09D183/04—Polysiloxanes
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D183/00—Coating compositions based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon, with or without sulfur, nitrogen, oxygen, or carbon only; Coating compositions based on derivatives of such polymers
  • C09D183/14—Coating compositions based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon, with or without sulfur, nitrogen, oxygen, or carbon only; Coating compositions based on derivatives of such polymers in which at least two but not all the silicon atoms are connected by linkages other than oxygen atoms
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
  • C09D5/23—Magnetisable or magnetic paints or lacquers
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
  • C09D7/40—Additives
  • C09D7/60—Additives non-macromolecular
  • C09D7/61—Additives non-macromolecular inorganic
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D2203/00—Other substrates
  • B05D2203/30—Other inorganic substrates, e.g. ceramics, silicon
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D2301/00—Inorganic additives or organic salts thereof
  • B05D2301/30—Acids
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D2401/00—Form of the coating product, e.g. solution, water dispersion, powders or the like
  • B05D2401/20—Aqueous dispersion or solution
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D2518/00—Other type of polymers
  • B05D2518/10—Silicon-containing polymers
  • B05D2518/12—Ceramic precursors (polysiloxanes, polysilazanes)
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/02—Elements
  • C08K3/08—Metals
  • C08K2003/0806—Silver
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/02—Elements
  • C08K3/08—Metals
  • C08K2003/0812—Aluminium
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/02—Elements
  • C08K3/08—Metals
  • C08K2003/0843—Cobalt
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/02—Elements
  • C08K3/08—Metals
  • C08K2003/085—Copper
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/02—Elements
  • C08K3/08—Metals
  • C08K2003/0856—Iron
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/02—Elements
  • C08K3/08—Metals
  • C08K2003/0862—Nickel
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K2201/00—Specific properties of additives
  • C08K2201/001—Conductive additives
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K2201/00—Specific properties of additives
  • C08K2201/002—Physical properties
  • C08K2201/005—Additives being defined by their particle size in general
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K2201/00—Specific properties of additives
  • C08K2201/002—Physical properties
  • C08K2201/006—Additives being defined by their surface area
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K2201/00—Specific properties of additives
  • C08K2201/01—Magnetic additives

Definitions

• the present invention relates to the field of induction compatible cookware.
• induction compatible it is understood within the meaning of the invention the ability to be compatible with the technique of induction heating, in particular compatible with induction hobs. It is understood that the expression “inductive” has the same meaning as the expression “compatible induction”.
• An induction heating cooking station is generally made up of an inductor supplied by an alternating current. When a conductive material is placed above this inductor, it is traversed by a variable magnetic flux and becomes the seat of an electromotive force of induction. The currents induced in the conductive material, called eddy currents, cause it to heat up by the Joule effect. This effect is the thermal manifestation of the electrical resistance that occurs when current flows throughout the conductive material. Thermal energy is transmitted to food by thermal conduction and therefore allows it to be heated. A representation of this principle is shown in Figure 1.
• Cookware which are induction compatible either because their support is inductive by nature or because their support has been treated to make it inductive or because an inductive part has been added to the support.
• Media that are inductive in nature are, for example, ferritic metal media (for example steel, stainless steel or cast steel) which may or may not be coated with a coating, in particular a non-stick coating.
• the supports made inductive are, for example, aluminum, glass, ceramic or copper supports, the outer bottom of which comprises a ferromagnetic insert (for example a ferritic metal part assembled to the support by striking or gluing) or of which the outer bottom was treated by a plasma deposit consisting of ferromagnetic elements as in patent FR 2882240.
• non-inductive supports such as those made of aluminum, glass, ceramic or copper are not easily enamelable (poor adhesion of the coating, pitting of the coating) and are expensive.
• Patent application FR 2882240 describes a plasma deposit made up of ferromagnetic elements outside the culinary article, in order to make it compatible with induction.
• the deposition of powder on the article causes surface roughness which must be smoothed out by sanding or by depositing a topcoat, in order to make the outer surface less uneven, thereby making the production process complex and expensive.
• this process carried out at very high temperatures (between 200 and 800 ° C.) and using powder, is restrictive, generating problems of working conditions and the safety of people working on the production line. It is therefore also necessary to overcome these constraints in order to guarantee the safety of people.
• such articles are not very resistant to the phenomena of hydrolysis, encountered during dishwasher cycles.
• a magnetically conductive coating is applied to the exterior of a ceramic cookware, for electromagnetic heating application, and includes an epoxy resin as a binding agent.
• Bisphenol A is a compound of epoxy resin and during the resin curing process it is often poorly evacuated. Thus a part of bisphenol A persists in the resin used as a binding agent and is applied to the culinary article. There is therefore a risk of toxicity for the end user, especially during thermal cycles. of use, with the release of decomposition by-products harmful to health and / or bisphenol A, a recognized endocrine disruptor which poses problems for public health.
• the Applicant has developed a sol-gel coating composition intended to make a cookware compatible with induction.
• a subject of the present invention is therefore a sol-gel coating composition comprising conductive fillers, intended to make a cookware compatible with induction.
• the present invention also relates to a cookware comprising a support coated with the sol-gel coating according to the invention.
• a subject of the present invention is therefore a sol-gel coating composition comprising conductive fillers intended to render a cookware compatible with induction.
• conductive charge or conductive material it is understood within the meaning of the invention a charge or a material capable of conducting electric currents, such as eddy currents.
• M 1 , M 2 or M 3 denote an element chosen from Si, B, Zr, Ti, Al, V.
• sol-gel precursor of metal or metalloid alkoxylate type or of sol-gel precursor of metal or metalloid polyalkoxylate type which can be used in the sol-gel coating composition according to the invention, mention may be made, among others, of aluminates, titanates, zirconates, vanadates, borates, polyalkoxysilanes and their mixtures.
• the sol-gel precursor is advantageously chosen from methyltrimethoxysilane (MTMS), tetraethoxysilane (TEOS), methyltriethoxysilane (MTES) and dimethyldimethoxysilane or their mixtures.
• MTMS methyltrimethoxysilane
• TEOS tetraethoxysilane
• MTES methyltriethoxysilane
• the sol-gel precursor comprises tetraethoxysilane (TEOS) and / or methyltriethoxysilane (MTES).
• the sol-gel coating composition according to the invention may further comprise at least one inorganic filler.
• inorganic filler are, for example, fillers chosen from boron nitride, molybdenum sulphide, graphite and their mixtures.
• organo-mineral coating is meant, within the meaning of the present invention, a coating whose network is essentially inorganic, but which comprises organic groups, in particular because of the precursors used and of the coating temperature or due to the incorporation of organic fillers.
• the term “entirely inorganic coating” means a coating based on an entirely inorganic material, free of any organic group. Such a coating can be obtained by sol-gel route with a firing temperature of at least 400 ° C, or from precursors of metal or metalloid alkoxylate type and / or precursors of metal or metalloidal polyalkoxylate type with a temperature of cooking which may be less than 400 ° C.
• the sol-gel coating according to the invention comprises a sol-gel material comprising a matrix formed from at least one metal or metalloid alkoxylate or at least one metal or metalloid polyalkoxylate and at least 2% by mass per relative to the total mass of the coating of at least one colloidal oxide, preferably a metal or metalloid oxide, dispersed in said matrix.
• the sol-gel coating according to the invention can be arranged on a support either in a single layer or in several layers superimposed on one another.
• the sol-gel coating according to the invention can be in the form of a continuous or discontinuous layer, in particular if it comprises a decoration.
• the decoration is applied by screen printing or pad printing.
• the decoration can be applied according to the process described in French patent FR2576253.
• the coating according to the invention forms a single, continuous layer. It can be envisaged that the sol-gel coating according to the invention forms a discontinuous layer.
• the sol-gel coating according to the present invention has a resistivity between 5.0.10 7 and 7.5.10 5 Qm, preferably between 8.0.10 7 and 3.6.10 5 Qm.
• the sol-gel coating according to the invention occurs in a solid state.
• a subject of the present invention is also a cookware comprising a support coated with the sol-gel coating according to the invention.
• the present invention also relates to a cookware comprising a support coated with the sol-gel coating according to the invention after implementation of the sol-gel coating composition according to the invention. After heat treatment, the sol-gel coating according to the invention adheres to the support of the culinary article to form an article, the support of which is coated with a sol-gel coating.
• part of the cookware support is coated with the sol-gel coating according to the invention, but it can be envisioned that the entire cookware support is coated. Generally, only the part which is intended to be in contact with the induction heating means, in particular induction hobs, is coated.
• Stoneware and ceramic may also be suitable as coating supports for the culinary article according to the invention.
• So-called "all fires" ceramics generally use specific products, the shaping of which requires a lot of know-how.
• the advantage of these materials is to withstand high thermal shocks.
• These materials are preferably molded by gravity casting or by conventional or isostatic pressure for better productivity. Molding techniques make it possible to obtain various shapes and then the molded materials are dried and baked, for example in stages up to 1400 ° C. in 4 hours.
• These rough objects also called shards (because they are not coated) have a certain interesting roughness associated with molding and which it is preferable to control for the application of the sol-gel coating according to the invention.
• a first layer of sol-gel coating composition according to the invention or not can be applied by spray to the outside of the article in order to provide a better aesthetic appearance and especially to create an effective adhesion primer to the layer.
• This “primer” layer is not essential since direct deposition by screen printing of the inductive sol-gel layer according to the invention is also possible.
• Plastic may also be suitable as a coating support for the culinary article according to the invention.
• it will be plastic suitable for food contact.
• silicone it is possible to cite silicone but, this being relatively flexible, it will be considered to arm it.
• syndiotactic polystyrene -30% FV resistant to 250 ° C which possibly offers a correct solution for a heating system.
• the sol-gel coating composition according to the invention may optionally be adapted specifically to this support. For cookware with plastic supports, they can be used as a "keep warm" back-up system.
• the support of the cookware according to the invention has an inner face intended to receive food and an outer face intended to be disposed towards the induction heating means.
• the coating according to the invention is arranged on at least one of the two faces of the support of the cookware, preferably on the outer face.
• the outer face of the support of the culinary article is coated with the sol-gel coating according to the invention.
• culinary article is meant within the meaning of the present invention an object which will be heated by an external heating system, such as frying pans, saucepans, sauté pans, casseroles, pots, braisers, stews, woks, pastry molds, caquelons, and more generally any container with handles and which is able to transmit the heat energy provided by this external heating system to a material or food in contact with said container.
• the culinary article coated with the sol-gel coating according to the invention is induction compatible, in particular with induction hobs having a power range of 45 watts to 3.5 kilowatts.
• the subject of the invention is also a method of manufacturing an induction compatible cookware according to the invention comprising the following successive steps
• step (i) and (ii) is that described above.
• the method according to the invention may further comprise, prior to step i) a step of surface treatment of the face of the support intended to be coated.
• This surface treatment can consist of a chemical treatment (chemical pickling in particular) or mechanical (sandblasting, brushing, emery grinding, shot blasting for example) or even physical (in particular by plasma), in order to create a roughness which will be favorable to adhesion. of the sol-gel coating layer.
• the surface treatment can also advantageously be preceded by a degreasing operation intended to clean the surface.
• step (ii) of the method according to the invention can take place according to the following sub-steps:
• aqueous composition comprising at least one colloidal oxide, preferably a metal or metalloid oxide, a solvent comprising at least one alcohol, and optionally at least one silicone oil; • preparing a solution (B), preferably acidic, comprising conductive fillers and at least one sol-gel precursor chosen from sol-gel precursors of metallic or metalloid alkoxylate type and sol-gel precursors of metallic or metalloidal polyalkoxylate type;
• a solvent comprising at least one alcohol in the aqueous composition (A) makes it possible to improve the compatibility of the aqueous composition (A) with the solution (B).
• aqueous composition (A) of the invention an oxygenated alcoholic solvent or an ether-alcohol.
• the solution (B) used in step (ii) can further comprise an organic acid such as, for example, acetic acid, formic acid, citric acid, hydrochloric acid or else acid. tartaric or their mixtures.
• organic acid such as, for example, acetic acid, formic acid, citric acid, hydrochloric acid or else acid. tartaric or their mixtures.
• the preferred acids according to the invention are organic acids, and more particularly acetic acid or formic acid.
• compositions (A) and (B) are mixed together, to form a sol-gel coating composition (A + B).
• the respective amounts of each of the compositions (A) and (B) are preferably adjusted so that the amount of colloidal silica in the sol-gel coating composition represents 2 to 30%, percentage by mass based on the mass of the total dry extract.
• the sol-gel coating composition (A + B) according to the invention can be applied to the support by spraying or by any other method of application, such as by dipping, with a pad, with a brush, with a roller, by jet. ink, curtain, coating centrifugal or by screen printing.
• spraying for example by means of a gun, has the advantage of forming a homogeneous and continuous layer which, after curing, forms a continuous coating, of regular thickness and tight.
• the application to the support, in step (ii) of the method according to the invention can take place by screen printing, by roller, by ink jet, by spraying or by curtain.
• the application to the support, in step (ii) of the process according to the invention can take place by pyrolysis spraying comprising spraying or nebulization in the form of droplets of solution of the sol-gel coating composition.
• the application to the support, in step (ii) of the process according to the invention can also take place by flat coating techniques, which allow, on the one hand, a significant saving in coating consumption of a industrial point of view, and on the other hand the elimination of the problem of spraying outside the article (or “over spray” in English).
• step (iii) of the process according to the invention can take place at a temperature of 200 to 400 ° C, in particular at a temperature of 210 to 300 ° C, more particularly at a temperature of 220 to 280 ° C. , preferably at 250 ° C.
• This optional drying step can allow the solvents to evaporate and avoid the constraints associated with the densification / curing of the coating.
• the method further comprises, between step ii) of applying the sol-gel coating composition to the support and step iii) of heat treatment, the two successive steps following: ii-1) a step of pre-densification of the support thus coated to obtain a sol-gel coating layer having a pencil hardness in the range 4B to 4H; then
• ii-2) a step of stamping the coated support until the final shape of the culinary article is obtained, with an inner face suitable for receiving food and an outer face intended to be placed on the side of a heat source , the face stamped which may be either the face provided with the sol-gel coating layer, or the face which is opposite to it.
• the term “pencil hardness” is understood to mean the resistance of the coatings or lacquers to surface scratches. This hardness therefore indirectly reflects a state of progress in the condensation of the sol-gel.
• This step of pre-densification of the sol-gel coating layer can advantageously consist of a step of drying at a temperature between 20 ° C and 150 ° C, and more particularly by forced drying at a temperature of 80 ° C. at 150 ° C in a conventional baking oven.
• the drying time may be between 30 seconds and 5 minutes.
• step (iii) of the process according to the invention an article is obtained, the support of which is coated with a sol-gel coating according to the invention.
• the thickness of the coating after carrying out the process according to the invention can be between 1 and 2000 ⁇ m, in particular between 2 and 1000 ⁇ m, preferably between 2 and 150 ⁇ m.
• the thickness of the coating after carrying out the method according to the invention with paramagnetic or diamagnetic conductive fillers can be between 1 and 40 pm, in particular between 2 and 30 pm, preferably between 5 and 15 pm.
• the thickness of the coating after carrying out the method according to the invention with ferromagnetic conductive fillers can be between 50 ⁇ m and 2 mm, in particular between 70 ⁇ m and 1 mm, preferably between 70 ⁇ m and 500 ⁇ m.
• the thickness of the coating will be a function of the D100 of the particles and in particular of the conductive fillers, and that the D 100 generally cannot be greater than the thickness of the coating so that no element of the coating protrudes.
• the D100 may be greater than the thickness of the coating, the oblong particles being coated in the coating without protruding from the coating layer.
• the invention also relates to the use of conductive fillers to prepare a sol-gel coating in order to make induction compatible a cookware.
• the conductive charges make it possible to make a cookware compatible with induction, following the dissipation of the power by the Joule effect at the level of the coating, resulting from the currents induced by the generator of the heating means.
• the conductive charges implemented according to this use are those described above.
• FIG.1 is a schematic sectional representation of an example of an induction heating system.
• a container 1 containing water to be heated is placed on an induction hob.
• This hob includes a glass ceramic plate 4, induction coils 5 forming an electromagnet and a power supply 6.
• the coils generate a magnetic field 3 which pass through the plate 4 and the bottom of the container 1.
• the latter becomes the seat of induced currents 2 causing it to heat up, and thus cause the heating by thermal conduction of the water contained in the container 1.
• the particle size distribution and the particle size are measured by laser particle size distribution, for example using a Malvern MS2000 laser particle size analyzer.
• the measurement is carried out in a suitable medium, either wet (for example, in aqueous or solvent medium) or dry.
• the light source consists of a class 1 laser, with a red He-Ne light emission source and a blue diode.
• the optical model is that of Mie and the computation matrix is of Mie type.
• the apparatus is calibrated regularly using a standard sample (several different monodisperse latex powders) whose particle size curve is known. It is necessary to know the refractive index of each material used in order to make the necessary corrections during the analysis by laser diffraction. The alignment of the laser and the cleanliness of the analysis chambers are checked before measurements.
• the light intensity of the laser is at least equal to 80%, and that a decreasing exponential curve is obtained for the background noise. If not, the lenses in the cell should be cleaned.
• the sample is introduced to obtain an obscuration slightly greater than 10%.
• the measurement is carried out in the presence of ultrasound (to avoid agglomerates) with a duration of 10 s (acquisition time of 10,000 diffraction images analyzed).
• ultrasound to avoid agglomerates
• the particle size distribution curve obtained it must be taken into account that part of the population of the powder could be agglomerated.
• the measurement is repeated at least twice to check the stability of the result and the evacuation of any bubbles.
• a sol-gel coating composition according to the invention was obtained.
• This sol-gel coating composition according to the invention was obtained according to the protocol described in Example 1.
• Example 3 sol-gel coating composition according to the invention comprising an aluminum powder (acid route)
• This sol-gel coating composition according to the invention was obtained according to the protocol described in Example 1.
• a sol-gel coating composition according to the invention was obtained.
• Example 1 The sol-gel coating composition of Example 1 was applied to a ceramic pottery support (pan-type container) so as to obtain a support coated with a sol-gel coating according to the invention according to the following protocol:
• the sol-gel coating composition of Example 1 was applied with a brush in one or more layers until a thickness of 30 ⁇ m was obtained, followed slow drying at a temperature of 80 to 120 ° C;
• the cooking step was carried out at around 250 ° C, starting with a rise in temperature to 250 ° C in 5 minutes, then maintaining the temperature for 10 minutes at 250 ° C, then cooling in 5 minutes .
• the resistivity of the sol-gel coating composition applied to the support was measured with a SOLEMS SQOHM-1 4-point multimeter.
• the calculated resistivity is 5.10 6 .

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• Chemical & Material Sciences (AREA)
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• Organic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Wood Science & Technology (AREA)
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• Chemical Kinetics & Catalysis (AREA)
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• Food Science & Technology (AREA)
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• Induction Heating Cooking Devices (AREA)
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• 2019
  • 2019-01-21 FR FR1900511A patent/FR3091876A1/fr active Pending
• 2020
  • 2020-01-17 US US17/424,032 patent/US20220095829A1/en active Pending
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  • 2020-01-17 EP EP20701185.9A patent/EP3914652A1/de active Pending
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