Classifications

• • 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
  • A47J27/00—Cooking-vessels
  • A47J27/002—Construction of cooking-vessels; Methods or processes of manufacturing specially adapted for cooking-vessels
• • 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
  • 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
  • B05D5/08—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures to obtain an anti-friction or anti-adhesive surface
• • 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
• • 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
  • B05D7/50—Multilayers
  • B05D7/52—Two layers
  • B05D7/54—No clear coat specified
  • B05D7/542—No clear coat specified the two layers being cured or baked together
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B33/00—Silicon; Compounds thereof
  • C01B33/02—Silicon
  • C01B33/021—Preparation
  • C01B33/027—Preparation by decomposition or reduction of gaseous or vaporised silicon compounds other than silica or silica-containing material
  • C01B33/029—Preparation by decomposition or reduction of gaseous or vaporised silicon compounds other than silica or silica-containing material by decomposition of monosilane
• • 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
  • C08G77/02—Polysilicates
• • 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
  • C08G77/04—Polysiloxanes
  • C08G77/06—Preparatory processes
• • 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
  • C08G77/04—Polysiloxanes
  • C08G77/14—Polysiloxanes containing silicon bound to oxygen-containing groups
  • C08G77/16—Polysiloxanes containing silicon bound to oxygen-containing groups to hydroxy groups
• • 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
  • C08K5/00—Use of organic ingredients
  • C08K5/54—Silicon-containing compounds
  • C08K5/541—Silicon-containing compounds containing oxygen
  • C08K5/5415—Silicon-containing compounds containing oxygen containing at least one Si—O bond
• • 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
  • C08K5/00—Use of organic ingredients
  • C08K5/54—Silicon-containing compounds
  • C08K5/544—Silicon-containing compounds containing nitrogen
• • 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
  • C09D183/02—Polysilicates
• • 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
  • C09D183/04—Polysiloxanes
  • C09D183/06—Polysiloxanes containing silicon bound to oxygen-containing groups
• • 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)
• • 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

Definitions

• the present invention relates generally to the field of household articles comprising a surface covered with a non-stick coating. More precisely, the present invention applies to the field of non-stick coatings for cooking surfaces of culinary articles and electrical cooking appliances. The present invention also relates to a method of manufacturing such articles.
• a non-stick coating including this sol-gel finishing layer according to the invention are that a household article provided with such a coating will retain its non-stick coating longer than other sol-gel coatings. 'use. The user will be able to keep their item for several additional years. Besides the obvious gain from an economic point of view and ecological, the user will obtain a greatly improved level of satisfaction during use, while potentially using less fat.
• finishing layer has optical properties compatible with the presence of visual attributes in the coating.
• finishing coat which is a surface layer; this layer leaving perfect visibility of the decorative layer while protecting it from abrasion and giving the coating its non-stick properties.
• Sol-gel coating means, for the purposes of the present invention, a coating synthesized by sol-gel method from a sol-gel composition.
• the coating thus obtained can be either organomineral or entirely mineral.
• sol-gel route it is understood within the meaning of the present invention, the principle of synthesis comprising the transformation of a solution based on precursors in the liquid phase into a solid, by a set of chemical reactions (hydrolysis and condensation) at low temperature.
• the coating thus obtained can be either organo-mineral, or entirely mineral.
• organo-mineral coating is meant, within the meaning of the present invention, a coating whose network is essentially inorganic, but which contains organic groups, in particular due to the precursors used and the baking temperature of the coating or due to the incorporation of organic fillers.
• entirely mineral coating is meant, within the meaning of the present invention, a coating based on an entirely inorganic material, free from any organic group.
• a coating can be obtained by sol-gel process with generally a baking temperature of at least 400°C, or from precursors of the metal alkoxylate type and/or precursors of the metal polyalkoxylate type with generally a baking temperature which can be lower than 400°C.
• the finishing coat according to the invention is obtained from a sol-gel composition.
• This composition comprises at least one sol-gel precursor, of the metal alkoxide precursor type.
• a sol-gel precursor suitable for the finishing layer according to the invention mention may be made of precursors of the metal alkoxylate type or of sol-gel precursors of the metal polyalkoxylate type, among others, aluminates, titanates, zirconates, vanadates, borates, polyalkoxysilanes and their mixtures.
• These compositions, synthesized by the sol-gel route from precursors of the metal polyalkoxylate type preferably have a hybrid network, generally of silica with grafted alkyl groups.
• the sol-gel (SG) composition of the finishing layer is generally obtained from a sol-gel (SG) mixture comprising at least one precursor of the metal alkoxide type.
• a metal alkoxide chosen from the group consisting of:
• Mi M2 or M3 designating a metal chosen from Si, Zr, Ti, Sn, Al, Ce, V, Nb, Hf, Mg B or Ln.
• the sol-gel finishing layer according to the invention is advantageously obtained from a sol-gel precursor which is a polyalkoxysilane.
• the sol-gel precursor is an alkoxysilane chosen from the group consisting of methyltrimethoxysilane (MTMS), methyltriethoxysilane (MTES), dimethyldimethoxysilane, and mixtures thereof.
• the sol-gel precursor is methyltrimethoxysilane (MTMS).
• MTMS methyltrimethoxysilane
• the sol-gel precursor of the finishing layer is not tetraethoxysilane (TEOS).
• the sol-gel composition of the finishing coat according to the invention is free of tetraethoxysilane (TEOS).
• the sol-gel composition of the finishing layer may further comprise a solvent, in particular a solvent comprising at least one alcohol.
• a solvent comprising at least one alcohol is hereinafter referred to as an “alcoholic solvent”.
• An alcohol is preferably a C1-C6 alcohol.
• a C1 -C6 alcohol means a saturated hydrocarbon chain, linear or branched, comprising 1 to 6 carbon atoms and comprising a hydroxy group (-OH) attached to a carbon atom.
• -OH hydroxy group
• the finishing layer according to the invention may also comprise a hydroxylated silicone oil.
• the composition of the finishing layer is obtained by hydrolysis of the sol-gel precursor by adding water and an acid or basic catalyst, then by condensation reaction leading to obtaining a sol-gel non-stick coating composition.
• composition of the sol-gel finishing layer may include an acid catalyst such as for example acetic acid, formic acid, citric acid, hydrochloric acid, tartaric acid or mixtures thereof.
• an acid catalyst such as for example acetic acid, formic acid, citric acid, hydrochloric acid, tartaric acid or mixtures thereof.
• composition of the sol-gel finishing layer may include a basic catalyst such as, for example, sodium hydroxide NaOH, potassium hydroxide KOH, ammonia Nh or mixtures thereof.
• a basic catalyst such as, for example, sodium hydroxide NaOH, potassium hydroxide KOH, ammonia Nh or mixtures thereof.
• the composition of the sol-gel finishing layer may also include a pigment filler.
• pigment fillers which can be used in the context of the present invention, mention may in particular be made of coated or uncoated mica, titanium dioxide, mixed oxides (spinels), alumino-silicates, iron oxides, carbon black. carbon, perylene red, metallic flakes, pigments, organic thermochromic dyes or mixtures thereof.
• These pigment fillers have the main effect of providing color, and in addition of improving the diffusion of heat, of improving the hardness (and durability) of the sol-gel non-stick coating and of having lubricating properties.
• composition of the sol-gel finishing layer may also comprise at least one inorganic filler.
• inorganic filler are, for example, fillers chosen from boron nitride, molybdenum sulphide, graphite and their mixtures.
• composition of the sol-gel finishing layer may also include at least one organic filler.
• the term household article means an object intended to meet the domestic needs of everyday life, in particular an article intended to receive heat treatment or intended to produce heat. In particular, it may be a culinary item or a household appliance item.
• an object which will be heated by an external heating system in particular a culinary article such as frying pans, saucepans, sauté pans, woks, crepe makers, stewpots, pots, casserole dishes, braising pans, daubines, barbecue grills, baking molds, fondue pots and which is capable of transmitting the heat energy provided by this external heating system to a material or food in contact with said object.
• an external heating system in particular a culinary article such as frying pans, saucepans, sauté pans, woks, crepe makers, stewpots, pots, casserole dishes, braising pans, daubines, barbecue grills, baking molds, fondue pots and which is capable of transmitting the heat energy provided by this external heating system to a material or food in contact with said object.
• a heating object having its own heating system in particular a household appliance, such as electrical cooking appliances such as a saucier.
• electric cooking appliance within the meaning of the present invention, we must understand a heating object having its own heating system such as an electric crepe maker, an electric raclette appliance, an electric fondue appliance, an electric grill, electric plancha, electric cooker, bread maker, electric pressure cooking appliance.
• the household article according to the invention comprising a support coated with a sol-gel non-stick coating. After heat treatment, the sol-gel coating adheres to the support of the household article according to the invention to form an article whose support is coated with a sol-gel coating.
• the support of the household item can be made of inorganic material, such as glass or ceramic, or of organic material such as plastic, or of metallic material, or of terracotta.
• the support may be metallic and may be made of aluminum or aluminum alloy, anodized or not, optionally polished, brushed, sandblasted or microblasted, or of steel optionally polished, brushed, sandblasted or microblasted, or of steel stainless steel possibly polished, brushed, sandblasted or microblasted, or in cast steel, aluminum or iron, or in copper possibly hammered or polished.
• the glass suitable as a coating support for the household item according to the invention can be tempered borosilicate or glass ceramic which have the advantage of good mechanical strength and good resistance to thermal shock.
• This type of supports can be obtained from glassmakers with expertise in formulations, molding and tempering.
• the molding operation and application of the coating composition can be separated, which can be advantageous for implementing a batch process.
• a chemical or mechanical treatment of the surface may possibly be useful to obtain a reinforced bond between the sol-gel coating and the glass support.
• the sol-gel non-stick coating of the household article according to the invention is placed on at least one of the two faces of the support of the culinary article, preferably on the interior face in contact with the food .
• the exterior face of the support of the household item according to the invention is coated with a sol-gel coating, in this case the entire support of the culinary item is coated.
• the sol-gel non-stick coating covering the support of the household article according to the invention comprises at least two layers, a first sol-gel layer in contact with the support (primary layer), and a second sol-gel layer free of silica or colloidal metal oxide.
• the first layer of the sol-gel non-stick coating of the household article according to the invention is also called the primer layer (sometimes referred to as “adhesion primer” or “primer”).
• This primer layer is intended to be in contact with the surface of the support of the article on which the coating will be deposited.
• this primer layer allows successive layers of the coating to adhere to the support.
• the sol-gel non-stick coating of the household item according to the invention may also comprise an intermediate layer (sometimes referred to as "midcoat”) between the primer layer and the finishing layer.
• the composition of the first sol-gel layer may comprise a solution based on precursors in the liquid phase comprising sol-gel precursors of the metal alkoxylate type and/or sol-gel precursors of the metal polyalkoxylate type.
• a metal alkoxylate chosen from the group consisting of:
• the first layer which is intended to be applied to the support may advantageously comprise methyltrimethoxysilane (MTMS) as a sol-gel precursor.
• MTMS methyltrimethoxysilane
• the composition of the first sol-gel layer comprises at least one sol-gel precursor of the metal alkoxylate type as described above and at least 2% by mass relative to the total mass of the composition. of at least one colloidal metal oxide dispersed in said composition.
• the composition of the first sol-gel layer is obtained by hydrolysis of the sol-gel precursor by adding water and an acid or basic catalyst, then by condensation reaction leading to obtaining a composition of sol-gel non-stick coating.
• composition of the first sol-gel layer may comprise a basic catalyst such as, for example, sodium hydroxide NaOH, potassium hydroxide KOH, ammonia NH4 or mixtures thereof.
• a basic catalyst such as, for example, sodium hydroxide NaOH, potassium hydroxide KOH, ammonia NH4 or mixtures thereof.
• the composition of the first sol-gel layer may further comprise a pigmentary filler.
• pigment fillers which can be used in the context of the present invention, mention may in particular be made of coated or uncoated mica, titanium dioxide, mixed oxides (spinels), alumino-silicates, iron oxides, carbon black. carbon, perylene red, metallic flakes, pigments, organic thermochromic dyes or mixtures thereof.
• These pigment fillers have the main effect of providing color, and in addition of improving the diffusion of heat, of improving the hardness (and durability) of the sol-gel non-stick coating and of having lubricating properties.
• composition of the first sol-gel layer may also comprise at least one organic filler.
• composition of the first sol-gel layer may further comprise at least one reactive or non-reactive silicone oil, for example a polydimethylsiloxane oil (PDMS oil).
• PDMS oil polydimethylsiloxane oil
• R2' designating an alkyl or phenyl group
• n being an integer corresponding to the maximum valence of the metals M2 or M3,
• the metal alkoxylate of the sol-gel solution of the second layer is an alkoxysilane.
• alkoxysilanes mention may in particular be made of methyltrimethoxysilane (MTMS), methyltriethoxysilane (MTES), dimethyldimethoxysilane, and mixtures thereof.
• the composition of the second sol-gel layer does not include tetraethoxysilane (TEOS) as sol-gel precursors.
• TEOS tetraethoxysilane
• the invention also relates to a method of manufacturing a household article according to the invention comprising the following successive steps: i. have a support comprising two opposite faces; he. shape the support to obtain a concave face and a convex face; ill. successively apply to the concave face of the support a sol-gel coating composition then a finishing coat according to the invention; iv. apply a heat treatment to the article from step (iii) at a temperature of 200 to 400°C; v. obtain a household item whose support is coated with a non-stick sol-gel coating.
• 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 stripping in particular) or mechanical (sanding, brushing, grinding, shot blasting for example) or even physical (in particular by plasma), in order to create a roughness of the surface of the support which will be favorable to the adhesion of the sol-gel coating layer.
• the surface treatment can also be advantageously preceded by a degreasing operation intended to clean the surface.
• the support is optionally cleaned and heated before application of the composition according to step (iii).
• the heating temperature can be between 40 and 80°C, this preheating prevents dripping during application.
• step (iii) of the process according to the invention may comprise an intermediate drying step which takes place after the application of the sol-gel coating composition and before the application of the finishing coat.
• the sol-gel coating composition can be applied to the support by spraying or by any other method of application, such as by dipping, by pad, by brush, by roller, by ink jet, by curtain , by centrifugal coating or by screen printing.
• spraying for example by means of a gun, has the advantage of forming a homogeneous and continuous layer, which, after cooking, forms a continuous coating, of regular and waterproof thickness.
• the application to the support, in step (iii) of the process 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 (iii) 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 (iii) 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 removal of the issue of spraying outside the article (or “over spray” in English).
• step (iv) of the process according to the invention can take place at a temperature of 200 to 400°C, in particular at a temperature of 220 to 350°C, more particularly at a temperature of 250 to 400°C. 320°C, preferably 300°C.
• a drying step can be considered between step (iii) and (iv). Any drying means can be considered, drying in an oven, drying by ultraviolet or infrared radiation, plasma drying, drying in the open air or a combination of these heating means. [0107] This optional drying step can allow the solvents to evaporate and avoid the constraints linked to the densification/cooking of the coating.
• the method further comprises, between step iii) of applying the sol-gel coating composition to the support and step iv) of heat treatment, the two successive steps: iii-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 iii-2) a step of stamping the coated support until obtaining the final shape of the culinary article, with an interior face capable of receiving food and an exterior face intended to be placed on the side of a source of heat, the stamped face being able to be either the face provided with the sol-gel coating layer, or the face opposite it.
• step ii) of formatting is deleted.
• pencil hardness means the resistance of coatings or lacquers to surface scratches. This hardness therefore indirectly reflects a state of progress of the condensation of the sol-gel.
• This step of pre-densification of the sol-gel coating layer can advantageously consist of a drying step at a temperature of 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 could be between 30 seconds and 5 minutes.
• step (v) of the process according to the invention an article is obtained whose support is coated with a sol-gel coating.
• the total thickness of the coating after implementation of the process according to the invention can be between 1 and 200 ⁇ m, in particular between 2 and 100 pm, preferably between 2 and 80 pm.
• Example 1 Preparation of a coating having a black sol-gel primer and glittery finishing layer:
• the formulation of the black primer (first layer) is prepared from a three-component system: part A, part B and part C.
• Part A is a colloidal silica, with a particle size less than 200 nm, which can optionally be impregnated with a hydrophobic compound such as PDMS oil.
• Part B integrates the MTMS reactive silane and the acid catalyst.
• Part C integrates the pigments, fillers, solvents, wetting agent, and PDMS oil.
• Example 1 black primary
• the formulation of the finish (finishing coat or second layer) according to the invention is also prepared from a three-component system, except that in part A there is only demineralized water, and it is free of colloidal silica.
• Part B comprises the MTMS reactive silane and the acid catalyst.
• Part C includes the solvents, the wetting agent, the flakes, and the PDMS oil.
• Example 1 glitter finishing layer according to the invention
• Part A (colloidal silica for the primary or demineralized water for the finish) is stirred with a shearing blade and a speed of 1,000 rpm, sufficient to obtain a clean vortex.
• Part B is prepared separately by mixing the silane with the acid, then introduced with stirring into part A: the MTMS hydrolysis reaction then begins, and must continue for at least 2 hours.
• part C is introduced into this mixture by incorporating the components one by one, still with stirring. It should be noted that we can also pre-mix all the components of part C separately, before introducing this paste into mixture A+B after the 2 hours of reaction.
• the mixture can also be stored in the refrigerator at 5°C: in this case, its shelf life is increased to at least 72 hours.
• the primary mixture is then filtered with a 50 micron filter before being applied by spray to a sandblasted and degreased aluminum support and previously shaped. The support is preheated to 55°C to avoid any sagging during coating.
• the finish is then filtered with a 90 micron filter, and applied to the wet primary layer.
• the primer will have a dry thickness of 30 to 40 microns, and the finish will have a dry thickness of 3 to 10 microns.
• Comparative Example 2 preparation of a coating including a black sol-gel primer and glitter topcoat with colloidal silica:
• the formulations based on MTMS are included, with a composition and process identical to Example 1 for the primer layer, but with a finishing layer containing colloidal silica.
• Comparative example glitter finishing layer containing silica

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Life Sciences & Earth Sciences (AREA)
• Wood Science & Technology (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
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• Application Of Or Painting With Fluid Materials (AREA)
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• 2022
  • 2022-08-30 FR FR2208659A patent/FR3139142B1/fr active Active
• 2023
  • 2023-08-29 KR KR1020257009377A patent/KR20250057827A/ko active Pending
  • 2023-08-29 CN CN202380062032.1A patent/CN119768094A/zh active Pending
  • 2023-08-29 EP EP23772300.2A patent/EP4580472A1/de active Pending
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