Classifications

• • 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
  • B05D7/544—No clear coat specified the first layer is let to dry at least partially before applying the second layer
• • 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
  • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D13/00—Electrophoretic coating characterised by the process
• • 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
  • B05D2451/00—Type of carrier, type of coating (Multilayers)

Definitions

• the present invention relates to a method for multi-layer coating of substrates with a primer layer made of electrocoat and a topcoat made of powder paint.
• the coating of primarily electrically conductive substrates with an electro-dip coating has been a process that has been common for many years.
• the electrocoat is in the form of an (aqueous) dispersion in a bath.
• the substrate to be coated is switched as one of two electrodes and immersed in this bath. This is followed by electrophoretic deposition of the electrocoat on the substrate. After a sufficiently thick layer of lacquer has been reached, the coating process is ended and the lacquer layer is dried and generally baked.
• Resins that can be electrodeposited on the cathode are e.g. in U.S. Patent 3,617,458. These are cross-linkable coating compounds that are deposited on the cathode. These coating compositions are derived from an unsaturated polymer which contains amine groups and carboxyl groups and an epoxidized material.
• US Pat. No. 3,663,389 describes cationically-electrodepositable compositions which are mixtures of certain amine-aldehyde condensates and a large number of cationic resinous materials, one of which is prepared by reacting an organic polyepoxide with a secondary amine and solubilizing with acid can be.
• aqueous dispersions are known which can be deposited electrically on the cathode and consist of an epoxy resin ester, water and tertiary amino salts.
• the epoxy diester is the reaction product of. a glycidyl polyether and a basic unsaturated oleic acid.
• the amine salt is the reaction product of an aliphatic carboxylic acid and a tertiary amine.
• Binder based on epoxy and polyurethane for the use of binder dispersions and pigment pastes are also known in numerous configurations. For example, reference is made to DE-27 01 002, EP-A-261 385, EP-A-004 090 and DE-PS 36 30 667.
• the coating of fabrics with powder coatings is also a common procedure.
• the powdered dry lacquer is applied evenly to the substrate to be coated.
• the paint is then melted and baked by heating the substrate.
• the special advantages of powder coatings include that they do not require solvents and that the losses associated with conventional coatings are avoided by overspray, since non-adhering powder coatings can be almost completely recycled.
• the powder coating is preferably applied to the substrate by electrostatic adhesion, which is generated by the application of high voltage or by frictional charging.
• the combination of the coating with electro-dip coating and with powder coating is also known from the prior art.
• a powder coating layer is first sintered on and then an electro-dipping coating is applied.
• an electrocoat layer is also known to apply an electrocoat and dry it at 110 ° C., to apply a powder coating and finally to bake both layers together.
• the product properties can be optimized through this two- or multi-layer coating. Priming with electrocoat can also be necessary for substrates that are made of materials or geometrical materials Reasons for powder coating are difficult to access.
• a typical application of this multi-layer coating is the coating of radiator radiators. The procedure is such that after the substrate has been coated with the electrocoating material, this lacquer is first baked in a dryer.
• the invention has set itself the task of developing a method for multi-layer coating of substrates with electrocoat and powder coating, which simplifies, saves energy and is more cost-effective for the same product qualities.
• This object is achieved according to the invention by a method in which a) at least one layer (2) of liquid lacquer, preferably of electrocoating lacquer, is applied to a substrate (1), preferably made of metal, in particular iron or zinc, b) optionally the substrate (1 ) is completely or partially dried after dipping, c) at least one layer of powder coating (3) is applied and d) electro-dipping coating and powder coating are baked together, the drying taking place at temperatures of ⁇ 100 ° C., preferably ⁇ 40 ° C.
• the method according to the invention accordingly dispenses with a separate drying and baking step for the electrocoat material before the powder coating is applied. Instead, both paints are baked in one step. This procedure considerably simplifies the coating process. By the Omitting a burn-in process reduces both investment and operating costs. Only a single baking oven needs to be made available and operated. This also saves heating energy. In addition, the total processing time for the coating process is shorter, so that the productivity of the system is increased.
• the substrate to be coated is preferably pre-primed with an electro-dip coating, this is primarily an electrically conductive substrate.
• it can be a metal, preferably iron or zinc.
• step a a liquid lacquer is applied to the substrate described according to the invention. All coating processes known from the prior art can be used for this.
• electrocoat materials can be used which contain epoxy resins, which are preferably amine-modified, and / or blocked aliphatic polyisocyanate, pigment paste and, if appropriate, further additives.
• the electrocoat layer is preferably dried by air drying, e.g. pre-dried using a blower.
• air drying e.g. pre-dried using a blower.
• the air can be dry air, e.g. Compressed air, act.
• temperatures of ⁇ 100 ° C are preferred.
• the drying process extends over a period of not more than 60 minutes.
• the drying time is preferably ⁇ 40 minutes, particularly preferably ⁇ 30 minutes, most preferably ⁇ 20 minutes.
• Pre-drying of the electrocoat layer is preferably carried out until its solvent content has decreased in such a way that, when it is subsequently baked, the substance of the layer decreases by less than 20%, preferably less than 13%. Because when baking an electrocoat, there is always a loss of substance due to the evaporation of residual solvents and the release of fission products that occur during the crosslinking of the paint. Outgassing of these substances can lead to the formation of bubbles, so that the lacquer layer as a whole is destroyed. However, if the predrying is carried out up to the maximum limits of the solvent content specified above, the outgassing of the remaining solvents and the cleavage products does not lead to a deterioration in the product quality.
• a powder coating is applied to the aforementioned electro-dip coating.
• the crosslinking temperatures of the powder coating are higher than those of the electrocoat.
• the Temperature difference at 5 to 60 ° C, more preferably at 10 to 40 ° C, most preferably at 10 to 30 ° C, most preferably at 10 to 20 ° C.
• the powder coating can consist of epoxy resins, including epoxidized novolaks, of crosslinking agents, preferably phenolic or amine hardeners or bicyclic guanidines, catalysts, fillers and optionally auxiliaries and additives.
• the powder coating materials used according to the invention preferably contain epoxy resins, phenolic crosslinking agents, catalysts, auxiliaries and, if appropriate, auxiliaries and typical powder additives, flow aids.
• Suitable epoxy resins are all solid epoxy resins with an epoxy equivalent weight between 400 and 3,000, preferably 600 to 2,000. These are mainly epoxy resins based on bisphenol A and bisphenol F. Expoxidized novolac resins are preferred. These preferably have an epoxy equivalent weight of 500 to 1,000.
• the epoxy resins based on bisphenol A and bisphenol F generally have a functionality of less than 2, which epoxidized
• Novolac resins have a functionality greater than 2. Epoxidized are particularly preferred in the powder coatings according to the invention.
• Epichlorohydrides are introduced into the molecule by epoxy groups.
• Epoxidized novolak resins can be produced by epoxidizing novolaks, which consist, for example, of 3 to 4 phenol cores which are connected to one another via methylene bridges. Alkyl-substituted phenols which are reacted with formaldehyde can also be used as novolak resins.
• Suitable epoxy resins are, for example, the products commercially available under the following names:
• Suitable epoxy functional binders for powder clearcoats are, for example, epoxy group-containing polyacrylate resins which can be prepared by copolymerizing at least one ethylenically unsaturated monomer which contains at least one epoxide group in the molecule with at least one further ethylenically unsaturated monomer which contains no epoxide group in the molecule, at least one of the monomers is an ester of acrylic acid or methacrylic acid.
• Polyacrylate resins containing epoxy groups are known (see e.g. EP-A-299420, DE-B-22 14 650, DE-B-27 49 576, US-A-4, 091,048 and US-A-3, 781, 379).
• Glycidyl acrylate, glycidyl methacrylate and allyl glycidyl ether are mentioned as examples of the ethylenically unsaturated monomers which contain at least one epoxy group in the molecule.
• Examples of ethylenically unsaturated monomers which do not contain an epoxy group in the molecule are alkyl esters of acrylic and methacrylic acid which contain 1 to 20 carbon atoms in the alkyl radical, in particular methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methyl acrylate, 2-ethylhexyl acrylate and Called 2-ethylhexyl methacrylate.
• Acids such as acrylic acid and methacrylic acid are further examples of ethylenically unsaturated monomers which contain no epoxide groups in the molecule.
• Acid amides such as, for example, acrylic acid and methacrylic acid amide, vinylaromatic compounds, such as styrene, methylstyrene and vinyltoluene, nitriles, such as acrylonitrile and methacrylonitrile, vinyl and vinylidene halides, such as vinyl chloride and vinylidene fluoride, vinyl esters, such as, for example, vinyl acetate and hydroxyl monomers containing groups such as hydroxyethyl acrylate and hydroxyethyl methacrylate.
• vinylaromatic compounds such as styrene, methylstyrene and vinyltoluene
• nitriles such as acrylonitrile and methacrylonitrile
• vinyl and vinylidene halides such as vinyl chloride and vinylidene fluoride
• vinyl esters such as, for example, vinyl acetate and hydroxyl monomers containing groups such as hydroxyethyl acrylate and
• the epoxy group-containing polyacrylate resin usually has an epoxy equivalent weight of 400 to 2,500, preferably 500 to 1,500, particularly preferably 600 to 1,200, a number average molecular weight (determined by gel permeation chromatography using a polystyrene standard) from 1,000 to 15,000, preferably from 1,200 to 7,000, particularly preferably from 1,500 to 5,000 and a glass transition temperature (TG) of 30 to 80, preferably from 40 to 70, particularly preferably from 50 to 70 ° C (measured with the aid of differential scanning calometry (DSC)).
• an epoxy equivalent weight 400 to 2,500, preferably 500 to 1,500, particularly preferably 600 to 1,200, a number average molecular weight (determined by gel permeation chromatography using a polystyrene standard) from 1,000 to 15,000, preferably from 1,200 to 7,000, particularly preferably from 1,500 to 5,000 and a glass transition temperature (TG) of 30 to 80, preferably from 40 to 70, particularly preferably from 50 to 70 ° C (measured with the aid
• the epoxy group-containing polyacrylate resin can be prepared by radical polymerization by generally well-known methods.
• Suitable hardeners for the epoxy group-containing polyacrylate resin are, for example, polyanhydrides of polycarboxylic acids or of mixtures of polycarboxylic acids, in particular polyanhydrides of dicarboxylic acids or of mixtures of dicarboxylic acids.
• Such polyanhydrides can be prepared by removing water from the polycarboxylic acid or the mixture of polycarboxylic acids, two carboxyl groups being converted into an anhydride group in each case. Such manufacturing processes are well known and therefore do not need to be explained in more detail.
• the powder coating according to the invention contains phenolic or amine hardeners. Bicyclic guanidines can also be used.
• phenolic resin Any phenolic resin can be used, for example, as long as it has the methylol functionality required for reactivity.
• Preferred phenolic resins are reaction products of phenol, substituted phenols and bisphenol A with formaldehyde, produced under alkaline conditions. Under such conditions, the methylol group is linked to the aromatic ring either ortho or para.
• preferred phenolic crosslinking agents are hydroxyl-containing bisphenol-A or bisphenol-F resins with a
• phenolic crosslinking agents are prepared by reacting bisphenol-A or bisphenol-F with components containing glycidyl groups, e.g. the diglycidyl ether of bisphenol-A.
• phenolic crosslinking agents are available, for example, under the trade names DEH 81, DEH 82 and DEH 87 from Dow DX 171 from Shell-Chemie and XB 3082 from Ciba Geigy.
• the epoxy resins and the phenolic crosslinking agents are used in such a ratio that the number of epoxy groups to the number of phenolic OH groups is approximately 1: 1.
• the powder coatings according to the invention contain one or more suitable catalysts for epoxy resin curing.
• Suitable catalysts are phosphonium salts of organic or inorganic acids, imidazole and imidazole derivatives, quaternary ammonium compounds and amines.
• the catalysts are generally used in proportions of 0.001% by weight to about 10% by weight, based on the total weight of the epoxy resin and the phenolic crosslinking agent.
• suitable phosphonium salt catalysts are ethyltriphenylphosphonium iodide, ethyltriphenylphosphonium chloride,
• Ethyltriphenylphosphoniumthiocyanat Ethyltriphenylphosphoniumthiocyanat
• Ethyltriphenylphosph ⁇ nium-acetate-acetic acid complex tetrabutylphosphonium iodide
• tetrabutylphosphonium bromide tetrabutylphosphonium acetate-acetic acid complex.
• suitable phosphonium catalysts are e.g. described in U.S. Patent Nos. 3,477,990 and 3,341,580.
• Suitable imidazole catalysts are, for example, 2-styrylimidazole, 1-benzyl-2-methylimidazole, 2-methylimidazole and 2-butylimidazole. These and other imidazole catalysts are e.g. described in Belgian Patent No. 756,693.
• Some commercial phenolic crosslinking agents already contain catalysts for epoxy resin crosslinking.
• Powder coatings based on carboxyl-containing polyesters and low molecular weight, epoxy-containing crosslinking agents are known in large numbers and are described, for example, in EP-A-389 926, EP-A-371 522, EP-A-326 230, EP-B-110 450, EP -A-110 451, EP-B-107 888, US 4,340,698, EP-B-119 164, WO 87/02043 and EP-B-10 805.
• Powder coatings according to DE 43 30 404.4 are particularly suitable, which are characterized in that they are used as film-forming material
• the carboxyl group-containing polyesters used as component A) have an acid number in the range from 10 to 150 mg KOH / g, preferably in the range from 30 to 100 mg KOH / g.
• the hydroxyl number of the polyester resins should be ⁇ 30 mg KOH / g.
• Polyesters with a carboxy functionality of> 2 are preferably used.
• the polyesters are produced according to the usual methods (compare e.g. Houben Weyl, Methods of Organic Chemistry, 4th edition, volume 14/2, Georg Thieme Verlag, Stuttgart 1961).
• Aliphatic, cycloaliphatic and aromatic di- and polycarboxylic acids are suitable as the carboxylic acid component for the production of the polyesters, e.g. Phthalic acid, terephthalic acid, isophthalic acid, trimellitic acid, pyromellitic acid, adipic acid, succinic acid, glutaric acid, pimelic acid, suberic acid,
• Cyclohexanedicarboxylic acid can also be used in the form of their esterifiable derivatives (e.g. anhydrides) or their transesterifiable derivatives (e.g. dimethyl ester).
• esterifiable derivatives e.g. anhydrides
• transesterifiable derivatives e.g. dimethyl ester
• Suitable alcohol components for the production of the carboxyl group-containing polyesters A) are the diols and / or polyols usually used, e.g. Ethylene glycol, propanediol-1, 2 and propanedio! -1, 3, butanediols, diethylene glycol, triethylene glycol, tetraethylene glycol, hexanediol-1, 6, neopentylglycol, 1, 4-
• polyesters suitable as component A) generally have one
• polyesters examples include the products commercially available under the following brand names.
• Unsaturated polyester resins containing carboxyl groups are also suitable as acidic polyester component A). These are obtained by polycondensation, for example of maleic acid, fumaric acid or other aliphatic or cycloaliphatic dicarboxylic acids with an ethylenically unsaturated double bond, optionally together with saturated polycarboxylic acids, as the polycarboxylic acid component.
• the unsaturated groups can also be replaced by the alcohol component, e.g. by
• Trimethylolpropane monoallyl ether into which polyester is introduced.
• the powder coating materials of the invention contain as component B) 0.8-20.1% by weight of low molecular weight epoxy groups
• triglycidyl isocyanurate triglycidyl isocyanurate
• TGIC is commercially available, for example, under the name Araldit PT 810 (manufacturer: Ciba Geigy).
• Other suitable low molecular weight curing agents containing epoxy groups are 1,2,4-triglycidyltriazolin-3,5-dione, diglycidyl phthalate and the diglycidyl ester of hexahydrophthalic acid.
• Polyacrylate resins (component C) containing epoxy groups are understood to mean polymers which are obtained by copolymerization of at least one ethylenically unsaturated monomer which contains at least one epoxy group in the molecule can be prepared with at least one further ethylenically unsaturated monomer which does not contain an epoxy group, at least one of the monomers being an ester of acrylic acid or methacrylic acid.
• Polyacrylate resins containing epoxy groups are known (see e.g. EP-A-299 420, DE-B-22 14650, US-A-4,091,048 and US-A-3, 781, 379).
• Glycidyl acrylate, glycidyl methacrylate and allyl glycidyl ether are mentioned as examples of ethylenically unsaturated monomers which contain at least one epoxy group in the molecule.
• ethylenically unsaturated monomers which do not contain an epoxy group in the molecule are alkyl esters of acrylic and methacrylic acid which contain 1 to 20 carbon atoms in the alkyl radical, in particular methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, isobutyl acrylate, t- Butyl acrylate and the corresponding methacrylates, 2-ethylhexyl acrylate and 2-ethylhexyl methacrylate called.
• acids such as e.g.
• Acrylic acid and methacrylic acid acid amides, e.g. Acrylic acid and methacrylic acid amide, vinyl aromatic compounds such as styrene, methyl styrene and vinyl toluene, nitriles such as acrylonitrile and methacrylonitrile, vinyl and vinylidene halides such as vinyl chloride and vinylidene fluoride, vinyl esters such as e.g. Vinyl acetate and vinyl propionate, and hydroxyl-containing monomers such as e.g. Hydroxyethyl acrylate and hydroxyethyl methacrylate.
• vinyl aromatic compounds such as styrene, methyl styrene and vinyl toluene
• nitriles such as acrylonitrile and methacrylonitrile
• vinyl and vinylidene halides such as vinyl chloride and vinylidene fluoride
• vinyl esters such as e.g. Vinyl acetate and vinyl propionate
• the polyacrylate resin (component C) containing epoxy groups has an epoxy equivalent weight of 350 to 2000.
• the polyacrylate resins containing epoxy groups have a number average molecular weight (determined by gel permeation chromatography using a polystyrene standard) from 1000 to 15000 and one Glass transition temperature (T G ) from 30 - 80 (measured using differential scanning calorimetry (DSC).
• the acrylate resin containing epoxy groups can be prepared by radical polymerization by generally well known methods.
• Polyacrylate resins containing such epoxy groups are commercially available, for example, under the names Almatex PD 7610 and Almatex PD 7690 (manufacturer: Mitsui Toatsu).
• the powder coating materials of the invention contain, as component D), 0.5-13.6% by weight of low molecular weight di- and / or polycarboxylic acids and / or di- and / or polyanhydrides as binders.
• Saturated, aliphatic and / or cycloaliphatic dicarboxylic acids are preferably used as component D), such as e.g. Glutaric acid, adipic acid, pimelic acid, suberic acid,fugic acid,
• Aromatic di- and polycarboxylic acids are also suitable as component D), e.g. Phthalic acid, terephthalic acid, isophthalic acid, trimellitic acid and pyromellitic acid, of course also in the form of their anhydrides, insofar as they exist.
• the amounts of the powder coating components A) to D) are chosen such that the ratio of the epoxy groups from B) and C) to the sum of the carboxyl and anhydride groups from A) and D) is 0.75-1, 25: 1. This ratio is preferably 0.9-1.1: 1.
• the powder coatings contain 50 to 90%, preferably 60 to 80% by weight of binder and 10 to 50% by weight, preferably 20 to 40% by weight of fillers.
• Silicic acid modifications into consideration. They are usually in the range from 10 to 50% by weight, based on the Total weight of the powder coating used. In some cases, however, filler contents of more than 50% by weight are also possible.
• the crystalline silica modifications include quartz, cristobalite, tridymite, keatite, stishovite, melanophlogite, coesite and fibrous silica.
• the crystalline silica modifications are glycidyl group functionalized, the glycidyl group functionalization being achieved by a surface treatment. These are, for example, silica modifications based on quartz, cristobalite and fused silica, which are produced by treating the crystalline silica modifications with epoxysilanes.
• the glycidyl group-functionalized silica modifications are available on the market for example under the names Silbond R 600 EST and Silbond R 6000 EST (manufacturer. Quarzwerke GmbH) and are produced by reacting crystalline silica modifications with epoxysilanes.
• the powder coatings advantageously contain 10 to 40% by weight, based on the total weight of the powder coating, of glycidyl group-functionalized crystalline silica modifications.
• the powder coatings can also contain other inorganic fillers, for example titanium oxide, barium sulfate and fillers based on silicate, such as e.g. Talc, kaolin, magnesium, aluminum silicates, mica and the like are included.
• the powder coatings may also contain auxiliaries and additives. Examples of these are leveling agents, trickling aids and degassing agents such as benzoin.
• degassing agents can be added to the powder coating to support non-destructive outgassing.
• concentrations of this degassing agent are preferably ⁇ 2% by weight, particularly preferably 0.1 to 0.8% by weight, very particularly preferably 0.2 to 0.5% by weight, most preferably £ 0.4% by weight .%.
• Compounds of the formula in particular come as degassing agents
• R is an alkanol with 1-6 C atoms.
• R T and R 2 are benzoyl or phenyl groups. Ri and R 2 can also be the same or different. Ie R, and R 2 can equally be benzoyl or phenyl groups. Likewise, one residue can be a benzoyl group, while the other residue is a phenyl group. Examples of preferred compounds are benzoylphenylmethanol (benzoin).
• the powder coatings are produced by known methods (see, for example, product information from the company BASF Lacke + Wegner AG, "Powder coatings", 1990) by homogenizing and dispersing, for example by means of an extruder, screw kneader, etc. After the powder coatings have been prepared, they are ground and, if necessary, adjusted to the desired particle size distribution by sifting and sieving.
• the powder coatings described are baked together with the electrodeposition coating after the application. During the baking of the electrocoat and powder coating layers there is a melting of the powder coating and thus its uniform distribution, as well as a hardening of the binders.
• the stoving is preferably carried out at temperatures of 150 to 220 ° C., very particularly preferably at 160 to 200 ° C.
• the baking process lasts 10 to 40 minutes, preferably 15 to 30 minutes.
• All common methods according to the state of the art can be used to apply the powder coating.
• Application by electrostatic adhesion preferably by applying a high voltage or by frictional charging, is particularly preferred.
• the method according to the invention is preferably used in the coating of radiators, car bodies and car accessories, machine parts, compressors, shelves, office furniture and comparable industrial products.
• the subject of the invention also includes a multi-layer coated substrate, which is characterized in that it is produced by first applying a layer of electro-dip lacquer to the substrate in an electro-immersion bath and then optionally drying, then applying a layer of powder lacquer and finally electro-dip lacquer and Powder coating can be baked together in one step.
• the electrocoat layer of the multi-coated substrate according to the invention preferably has a thickness of 5 to 35 ⁇ m, very particularly preferably 10 to 25 ⁇ m.
• the powder coating layer preferably has a thickness of 30 to 200 ⁇ m, very particularly preferably 50 to 120 ⁇ m.
• FIGS. 1 and 2 The implementation of the method according to the invention and the production of the substrate according to the invention is shown schematically in FIGS. 1 and 2.
• Figure 1 shows the layer structure of the substrate.
• Figure 2 shows the manufacturing steps.
• Figure 1 shows schematically the layer structure of the substrate according to the invention.
• the layer 2 of electro-dip lacquer which is usually covered by a layer 3 of powder lacquer which is 10 times thicker.
• the substrate is first coated in an electro-immersion bath 4. Then it will be produced.
• Electrodeposition bath removed and dried in a drying system 5 by blowing with air. Then, for example, creating a High voltage in a cabin 6 powder paint sprayed finely distributed on the surface of the substrate. This powder coating is then baked in the oven 7 together with the electrocoat layer at temperatures of approximately 150 to 220 ° C.
• Dodecylphenol and 105 g of xylene are initially charged and melted at 120 ° C. under a nitrogen atmosphere. Then, under a light vacuum
• the resin has a solids content of 70.2% and a base content of 0.97 milliequivalents / gram.
• reaction product After completion of the addition for a further 1 h stirred at 75 ⁇ C and then with 30 g of n-butanol diluted and cooled, the reaction product has a solids content of 79.6% (1 h at 130 ° C) and an amine number of less than 5 mg KOH / g
• Ethylene glycol monobutyl ether and 18 g of glacial acetic acid are then stirred in. Then 678 g of deionized water are added in 4 portions. Subsequently, the mixture is diluted with a further 1154 g of deionized water in small portions
• aqueous dispersion is freed of low-boiling solvents in a vacuum distillation and then diluted to a solids content of 33% by weight with deionized water 4.
• Parameter voltage between 100 and 400 V, preferably 150 to 300 V, temperature 24 to 35 ° C, preferably 28 to 32 ° C
• the heating element is then rinsed and blown off with air until no more liquid drips off.
• the heating element is then coated with powder from the outside and placed in a drying oven at 150 to 220 ° C., preferably at 160 to 200 ° C. for 10 to 40 minutes. preferably baked 15 to 30 mm
• the baking losses of the KTL should preferably be at most 15%, preferably at most 13% Powder example:
• the radiator is electrostatically coated with powder coating from the outside. Parameters gun voltage 50 to 90 kilovolts, distance gun / radiator 15 to 45 cm

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• Chemical & Material Sciences (AREA)
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• Organic Chemistry (AREA)
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• Electrochemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Wood Science & Technology (AREA)
• Paints Or Removers (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
• Production Of Multi-Layered Print Wiring Board (AREA)

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• 1996
  • 1996-02-23 DE DE19606706A patent/DE19606706A1/de not_active Ceased
• 1997
  • 1997-02-21 JP JP9514533A patent/JP2000505718A/ja active Pending
  • 1997-02-21 EP EP97903348A patent/EP0881955B1/fr not_active Revoked
  • 1997-02-21 DE DE59711545T patent/DE59711545D1/de not_active Expired - Fee Related
  • 1997-02-21 WO PCT/EP1997/000831 patent/WO1997030796A1/fr not_active Application Discontinuation
  • 1997-02-21 AT AT97903348T patent/ATE264720T1/de not_active IP Right Cessation
  • 1997-02-21 US US09/125,493 patent/US6254751B1/en not_active Expired - Fee Related
• 2001
  • 2001-01-26 US US09/770,902 patent/US20010011639A1/en not_active Abandoned

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