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EP1192013B1 - Method for refinishing defects in stoved enamels with powder coatings - Google Patents

Method for refinishing defects in stoved enamels with powder coatings Download PDF

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Publication number
EP1192013B1
EP1192013B1 EP00938741A EP00938741A EP1192013B1 EP 1192013 B1 EP1192013 B1 EP 1192013B1 EP 00938741 A EP00938741 A EP 00938741A EP 00938741 A EP00938741 A EP 00938741A EP 1192013 B1 EP1192013 B1 EP 1192013B1
Authority
EP
European Patent Office
Prior art keywords
defects
process according
powder coating
nir
powder
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP00938741A
Other languages
German (de)
French (fr)
Other versions
EP1192013A2 (en
Inventor
Armin Rettig
Olaf Thiele
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
EIDP Inc
Original Assignee
EI Du Pont de Nemours and Co
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Filing date
Publication date
Application filed by EI Du Pont de Nemours and Co filed Critical EI Du Pont de Nemours and Co
Publication of EP1192013A2 publication Critical patent/EP1192013A2/en
Application granted granted Critical
Publication of EP1192013B1 publication Critical patent/EP1192013B1/en
Anticipated expiration legal-status Critical
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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
    • B05D5/00—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures
    • B05D5/005—Repairing damaged 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
    • B05D2401/00—Form of the coating product, e.g. solution, water dispersion, powders or the like
    • B05D2401/30—Form of the coating product, e.g. solution, water dispersion, powders or the like the coating being applied in other forms than involving eliminable solvent, diluent or dispersant
    • B05D2401/32—Form of the coating product, e.g. solution, water dispersion, powders or the like the coating being applied in other forms than involving eliminable solvent, diluent or dispersant applied as powders
    • 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
    • B05D3/0263—After-treatment with IR heaters

Definitions

  • the invention relates to the refinishing of defects within burned-in Coating layers with powder coating agents.
  • a particular problem in the refinishing of outer, visible, from Powder-coated topcoats with liquid coatings are the ones To carry out refinishing in such a way that the repaired area is not noticeable, for example, with regard to color matching or gloss.
  • Repair of burned-on powder clearcoat layers is also not essential Deviation between the refractive indices of the baked powder clearcoat and the result in hardened repair clearcoat
  • DE-A-38 33 225 and DE-A-197 20 894 Process for repairing defects in lacquer layers while avoiding the usual thermal curing by convection or ordinary IR radiation are known from DE-A-38 33 225 and DE-A-197 20 894.
  • the ones described there Processes work with laser light as an energy source for curing the Repair paint.
  • DE-A-197 20 946 describes a method for repairing Flaws in an enamel finish, the flaw being ready for repair is coated with a lacquer coating agent and then the applied lacquer by irradiation with a laser beam source in the form of an Nd: YAG laser, the one Near infrared radiation is generated, cured.
  • EP-A-0 842 710 describes a method for repairing defects Powder coating layers known, in which prepared for repair, for example a milled or milled defect and a filler is inserted is connected.
  • the filler preferably corresponds to the dimensions of the prepared defect.
  • EP-A-0 887 118 improves that from EP-A-0 842 710 known methods with regard to the achievable quality of the repaired defect, by carrying out the method known from EP-A-0 842 710 so that the Filler and defect are connected under the influence of pressure.
  • EP-A-0 842 710 and EP-A-0 887 118 avoid the disadvantages the repair of imperfections in powder coatings using liquid coatings but still complex due to the necessary provision of the packing, especially in the dimension adapted to the defect to be repaired.
  • the object of the invention is, based on DE-A-197 20 894, an improved method for refinishing Flaws in stove enamels, especially when used stoving paint produced by powder coatings to provide the avoids disadvantages of the prior art described.
  • the procedure is supposed to be particularly suitable for touch-up painting of series-painted, industrially manufactured objects, in particular motor vehicles and their parts, for example in the context of or following a series painting.
  • the invention therefore relates to a method for repairing defects in a stove enamel, which is characterized in that the for Faulty areas ready for refinishing are coated with a clearcoat coating agent and the applied powder coating is then irradiated with near infrared radiation (NIR), which is generated with NIR emitters, melted and cured.
  • NIR near infrared radiation
  • the one or more defects become within a stove enamelling, especially within one of a Powder coating agent applied stove enamel using a Powder coating agent repainted.
  • Stove enamels can be, for example, single-coat top coats or are paint layers arranged within a multilayer paint system, for example primers, filler layers and preferably outer, visible color and / or effect or in particular transparent Topcoats.
  • the method according to the invention can preferably be used when repairing defects within burned-in powder coatings, especially powder clearcoats of coated layers. Can be particularly preferred the method according to the invention can be used in the repair of defects within applied to motor vehicles and their parts Baking finishes.
  • imperfections means that there are locally limited, for example up to a few square centimeters large, for example 1 mm 2 to 100 cm 2 large, defective areas within stoving lacquers.
  • the defects can be, for example, damage such as scratches, for example assembly scratches, coating defects such as craters or dents, or inclusions of dirt.
  • Powder coating compositions aqueous preparations of powder coating compositions, include so-called aqueous powder coating slurries. Are preferred in However, the process according to the invention uses powder coatings themselves.
  • the powder coatings used as refinish coatings in the process according to the invention contain a thermally curable self or externally cross-linking Binder system, preferably a crosslinking binder / hardener combination.
  • the film-forming higher molecular component is one thermosetting powder coating, which is generally at least 50% by weight of the underlying binder / hardener combination, while the Hardener component generally a maximum of 50 wt .-% within this combination is.
  • the binder base is not subject to any fundamental restrictions.
  • conventional binders used for powder coatings are suitable. Examples are polyester resins, (meth) acrylic copolymers, epoxy resins, phenolic resins, Polyurethane resins, siloxane resins.
  • the binders have, for example Glass transition temperatures of 30 to 120 ° C, preferably below 90 ° C, on and have, for example, number-average molar masses (Mn) of 500 to 20,000, preferably less than 10,000.
  • the hardeners have e.g. number average molar masses (Mn) from 84 to 3000, preferably less than 2000. Different binders and hardeners can be used be mixed together.
  • Binders and hardeners have complementary reactive functionalities Groups that allow a thermal crosslinking reaction of the powder coating, for example by condensation reactions and / or addition reactions.
  • functional groups carboxyl groups, epoxy groups are aliphatic or aromatically bound hydroxyl groups, isocyanate groups Isocyanate groups, anhydride groups, primary or secondary amino groups, blocked amino groups, N-heterocyclic groups capable of ring-opening addition Groups such as Oxazoline groups, (meth) acryloyl groups, CH-acidic groups such as e.g. Acetoacetate.
  • the selection of the groups which react with one another is familiar to the person skilled in the art. It can optionally combine different reactive groups with each other become. This can be done using binders that are different reactive functional Wear groups, or mixtures of different hardeners and / or Binders used.
  • the different functional groups can be on the binder and / or Be harder.
  • the binders and hardeners contain on average at least 2 functional groups per molecule.
  • the ratio of binder to Hardener is generally, for example, 98: 2 to 50:50. It is preferably between 95: 5 and 70: 30.
  • binder / hardener systems customary in powder coatings are polyester resins with low molecular weight epoxy or hydroxyalkylamide hardeners, epoxy / polyester hybrid systems, Epoxy resins with dicyandiamide hardener, carboxylic acid hardeners or phenolic hardeners, hydroxy-functional polyesters or (meth) acrylic copolymers with blocked polyisocyanates, epoxy-functional (meth) acrylic copolymers with Carboxylic acid or carboxylic anhydride hardeners.
  • Refinish paints are preferably used in powder clearcoats that are used as binders epoxy-functional (meth) acrylic copolymers, in particular Glycidyl (meth) acrylate copolymers with an epoxy equivalent weight between 250 and 700 and one or more low molecular weight and / or polymeric hardeners Compounds with an average of 2 or more carboxyl functions per molecule and / or anhydrides thereof.
  • Solid aliphatic hardeners are preferred Dicarboxylic acids and / or their anhydrides such as in particular dodecanedicarboxylic acid, which can also be used in a mixture with carboxyl-functional polyesters.
  • the powder coating materials used in the process according to the invention can be customary Powder coating additives in the usual proportions of, for example, 0.1 to 5% by weight contain.
  • additives are leveling agents, degassing agents such as e.g. Benzoin, antioxidants, light stabilizers, matting agents, color and / or effect-giving inorganic and / or organic pigments and / or fillers, Dyes, adhesion promoters, lubricants, catalysts and rheology control agents.
  • Powder coatings can be made using the usual methods for producing powder coatings done, for example, by extruding the dry mix of all required components of the formulated powder coating in the form of a pasty Melt, cooling of the melt, coarse comminution, fine grinding and optionally subsequent sieving to the desired fineness, for example to average particle sizes from 10 to 90 ⁇ m.
  • the process according to the invention can be carried out using fine-grained Powder coating, for example with average particle sizes of 1 to 40 microns become.
  • Fine-grained powder coating or powder coating fine grain can be produced in a targeted manner but falls, for example, in powder coating production or in Powder coating application as an undesirable material per se and can therefore in methods according to the invention can be used sensibly.
  • the powder coatings can also be used as an aqueous powder coating slurry.
  • a powder coating melt or organic powder coating solution in water be converted into an aqueous powder coating slurry, which if necessary by Organic solvent can be removed by distillation.
  • the powder coatings used in the process according to the invention preferably have the same solid composition as that previously used to manufacture the repairing varnish with stoving lacquer layer used. This is preferably a repair of defects in the burned-in area Powder coating layers. Both the initial painting and the Repair coating according to the invention powder coatings with identical Composition used. This is particularly advantageous when repairing Defects in outer, visible, baked clear lacquer layers. For example soft intrinsic color and refractive index of the initial and refinishing paint do not differ from each other.
  • imperfections are found in a stove enamelling repaired using powder coatings as refinish.
  • the missing parts can be ready for refinishing directly or they will be used Prepared refinish, for example by grinding, milling or Machining the defects with a laser. Generally the flaws at least cleaned before applying the powdered refinish.
  • the flawlessly coated surface portions of the surface in front of one To protect contamination for example by covering, masking or by Applying a peeling varnish around the defects to be repaired.
  • the defects that are ready for refinishing can be irrespective of whether they are on horizontal or vertical surfaces with the Powder coating agents are coated, for example mechanically, for example by sprinkling, brushing or brushing or application is carried out by spraying with the usual application equipment.
  • the mechanical application is particularly suitable for fine-grained powder coating material.
  • the spraying can be carried out, for example, with electrostatic assistance, e.g. With With the help of corona or tribo spray organs.
  • the powder coating composition applied to the defect is melted and cured by exposure to NIR radiation, preferably high-intensity NIR radiation.
  • MR radiation is short-wave infrared radiation in the wavelength range from approximately 760 to approximately 1500 nm, preferably 760 to 1200 nm.
  • NIR emitters are commercially available (for example from Industrie SerVis). These are, for example, high-performance halogen lamps with a radiation density of generally more than 1 W / cm 2 , preferably more than 10 W / cm 2 , for example up to 15 MW / m 2 .
  • the emitters for example, reach an emitter surface temperature (filament temperature) of between 2000 and 3000 K.
  • Suitable emitters for example, have an emission spectrum with a maximum between 750 and 1200 nm.
  • the irradiation period in the method according to the invention is, for example, 1 up to 300 seconds. When irradiated, it melts to repair the defect applied powder coating and hardens, for example, within 1 to 300 Seconds, preferably within 5 to 60 seconds.
  • the radiation can be equipped with one or more NIR emitters Conveyor system or with a NIR emitter that is in front of the object to be irradiated or the position to be irradiated is carried out.
  • the first option is available, for example, for refinishing of individual parts or objects in which several defects are present in one step to be repaired.
  • the belt speed and thus the Irradiation time can be varied.
  • belt speeds of 1 to 7 m / min can be set, which for example irradiation times from 2 to 20 Seconds.
  • the distance between the NIR emitter and Object surface can e.g. 1 to 60 cm, preferably 4 to 20 cm.
  • the NIR emitter is placed in front of the object to be irradiated or the position to be irradiated.
  • the radiation duration can e.g. 1 to 300 seconds, the object distance e.g. 1 to 60 cm, preferably 4 to 20 cm.
  • the different radiation parameters such as belt speed or Irradiation time, object distance, radiation power of the NIR emitter used can by the specialist according to the needs of each Repair task to be adjusted.
  • the powder coating applied to repair defects has hardened by means of NIR radiation, it may be expedient to smooth the repaired area, for example by polishing.
  • the method according to the invention permits the refinishing of defects in Stove enamels, especially within using Powder coatings produced stove enamels.
  • the ones described at the beginning Disadvantages of the prior art can be avoided.
  • the procedure is suitable for touch-up painting of mass-produced, industrially manufactured Items, in particular it is suitable for repairing imperfections within generated in the context of automotive or automotive parts series painting Powder coating layers, in particular powder topcoat and powder clearcoat layers.
  • the dirt particle is removed by sanding without penetrating the basecoat.
  • An approx. 0.5 cm 2 defect in the powder clear coat layer ready for repair is created.
  • the area to be repaired is separated from the flawless surface by masking with heat-unstable film.
  • the defect that is ready for repair is removed by electrostatic spraying same powder clearcoat applied as that used to produce the first coat powder clearcoat used.
  • An NIR emitter from Industrie SerVis is positioned at a distance of 100 mm from the flaw coated with powder clear lacquer. It is irradiated for 8 seconds with a power of 400 kW / m 2 , within which the powder clear lacquer melts and hardens completely.

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  • Application Of Or Painting With Fluid Materials (AREA)
  • Paints Or Removers (AREA)

Abstract

Method of repairing defective areas in a stoving lacquer coating, in which the defective area ready for repair lacquering is coated with a powder coating composition or with an aqueous powder coating slurry, and the applied powder coating is then melted and cured by irradiation with near infrared radiation (NIR).

Description

Die Erfindung betrifft die Reparaturlackierung von Defekten innerhalb eingebrannter Überzugsschichten mit Pulverüberzugsmitteln.The invention relates to the refinishing of defects within burned-in Coating layers with powder coating agents.

Lackdefekte wie beispielsweise Krater. Delien. Kratzer oder Schmutzeinschlüsse innerhalb von Einbrennüberzugsschichten. beispielsweise innerhalb von aus Pulverlacken hergestellten eingebrannten Überzugsschichten können mit Flüssiglacken repariert werden. Der Reparaturvorgang ist zeitaufwendig und arbeitsintensiv. Beispielsweise bedingt die Aushärtung des Reparaturlacks die Einwirkung erhöhter Temperaturen während eines ausreichend langen Zeitraums. Handelt es sich bei den reparaturzulackierenden Substraten um temperaturempfindliche Substrate, so kann die Objekttemperatur nicht beliebig hoch gewählt werden. Im Falle reparaturzulackierender Substrate mit einem gemischten Aufbau aus temperaturempfindlichen und temperaturunermpfindlichen Bauteilen wird im allgemeinen so verfahren, daß die temperaturempfindlichen Bauteile vor der Temperatureinwirkung, beispielsweise im Einbrennofen abgebaut und anschließend wieder angebaut werden. Diese Maßnahmen behindern und verteuern insbesondere Serienlackierprozesse, beispielsweise die Lackierung von Automobilen mit Füller-, Deck- oder Klarlacken.Lack defects such as craters. Delien. Scratches or dirt inclusions within baked coating layers. for example inside of Powder-coated baked coating layers can be made with liquid paints be repaired. The repair process is time consuming and labor intensive. For example, the curing of the refinish increases the exposure Temperatures for a sufficiently long period. Is it the substrates to be repaired to temperature sensitive substrates, so the Object temperature cannot be chosen arbitrarily high. In the event of repairable substrates with a mixed structure Temperature sensitive and temperature resistant components are used in the generally proceed in such a way that the temperature-sensitive components before Exposure to temperature, for example degraded in the baking oven and then to be grown again. These measures hinder and make them more expensive Series painting processes, for example painting automobiles with filler, Topcoats or clear coats.

Ein besonderes Problem bei der Reparaturlackierung von äußeren, sichtbaren, aus Pulverlacken hergestellten Einbrenndecklackierungen mit Flüssiglacken ist es, die Reparaturlackierung so auszuführen, daß die reparierte Stelle optisch nicht auffällt, beispielsweise hinsichtlich Farbtonübereinsammung oder Glanz. Im Fall der Reparatur eingebrannter Pulverklarlackschichten darf sich zudem keine wesentliche Abweichung zwischen den Brechzahlen des eingebrannten Pulverklarlacks und des ausgehärteten Reparaturklarlacks ergeben A particular problem in the refinishing of outer, visible, from Powder-coated topcoats with liquid coatings are the ones To carry out refinishing in such a way that the repaired area is not noticeable, for example, with regard to color matching or gloss. In the case of Repair of burned-on powder clearcoat layers is also not essential Deviation between the refractive indices of the baked powder clearcoat and the result in hardened repair clearcoat

Verfahren zur Reparatur von Fehlstellen in Lackschichten unter Vermeidung der üblichen thermischen Aushärtung durch Konvektion oder gewöhnliche IR-Bestrahlung sind aus den DE-A-38 33 225 und DE-A-197 20 894 bekannt. Die dort beschriebenen Verfahren arbeiten mit Laserlicht als Energiequelle für die Aushärtung des Reparaturlacks. Die DE-A-197 20 946 beschreibt ein Verfahren zur Reparatur von Fehlstellen in einer Einbrennlackierung, wobei die zur Reparatur bereite Fehlstelle mit einem Lacküberzugsmittel beschichtet wird und der aufgebrachte Lack anschließend durch Bestrahlen mit einer Laserstrahlquelle in der Form eines Nd:YAG-Lasers, der eine Nahinfrarot-Strahlung erzeugt, ausgehärtet wird.Process for repairing defects in lacquer layers while avoiding the usual thermal curing by convection or ordinary IR radiation are known from DE-A-38 33 225 and DE-A-197 20 894. The ones described there Processes work with laser light as an energy source for curing the Repair paint. DE-A-197 20 946 describes a method for repairing Flaws in an enamel finish, the flaw being ready for repair is coated with a lacquer coating agent and then the applied lacquer by irradiation with a laser beam source in the form of an Nd: YAG laser, the one Near infrared radiation is generated, cured.

Aus der EP-A-0 842 710 ist ein Verfahren zur Reparatur von Fehlstellen in Pulverlackschichten bekannt, bei dem in die zur Reparatur vorbereitete, beispielsweise ausgeschliffene oder ausgefräste Fehlstelle ein Füllkörper eingesetzt und damit verbunden wird. Bevorzugt entspricht der Füllkörper dabei den Abmessungen der vorbereiteten Fehlstelle. Die EP-A-0 887 118 verbessert das aus EP-A-0 842 710 bekannte Verfahren hinsichtlich der erreichbaren Qualität der reparierten Fehlstelle, indem das aus EP-A-0 842 710 bekannte Verfahren so ausgeführt wird, daß die Verbindung von Füllkörper und Fehlstelle unter Einwirkung von Druck erfolgt. Die Verfahren der EP-A-0 842 710 und EP-A-0 887 118 vermeiden zwar die Nachteile der Reparatur von Fehlstellen in Pulverlackschichten mittels flüssigen Lacken, sind aber dennoch aufwendig aufgrund der notwendigen Bereitstellung der Füllkörper, insbesondere in der der zu reparierenden Fehlstelle angepaßten Abmessung.EP-A-0 842 710 describes a method for repairing defects Powder coating layers known, in which prepared for repair, for example a milled or milled defect and a filler is inserted is connected. The filler preferably corresponds to the dimensions of the prepared defect. EP-A-0 887 118 improves that from EP-A-0 842 710 known methods with regard to the achievable quality of the repaired defect, by carrying out the method known from EP-A-0 842 710 so that the Filler and defect are connected under the influence of pressure. The Methods of EP-A-0 842 710 and EP-A-0 887 118 avoid the disadvantages the repair of imperfections in powder coatings using liquid coatings but still complex due to the necessary provision of the packing, especially in the dimension adapted to the defect to be repaired.

In dem Beitrag "Sekundenschnelle Aushärtung von Pulverlack'' (Kai Bär, JOT 2/98, Seite 26 bis 29) wird beschrieben, daß sich Pulverlacke mit Hilfe von Nahinfrarot-Strahlung (NIR) hoher Intensität aushärten lassen, ohne daß es zu einer wesentlichen Erwärmung des Substrates kommt. Die NIR-Technologie erlaubt das Aufschmelzen und die Aushärtung von Pulverlacküberzügen in einem einzigen Prozeßschritt. In the article "Fast curing of powder coating '' (Kai Bär, JOT 2/98, Pages 26 to 29) describe that powder coatings with the help of near infrared radiation Allow high intensity (NIR) to cure without becoming essential Heating of the substrate comes. The NIR technology allows melting and the curing of powder coatings in a single process step.

Aufgabe der Erfindung ist es, ausgehend von DE-A-197 20 894, ein verbessertes Verfahren zur Reparaturlackierung von Fehlstellen in Einbrennlackierungen, insbesondere innerhalb von unter Verwendung von Pulverlacken hergestellten Einbrennlackierungen bereitzustellen, das die beschriebenen Nachteile des Standes der Technik vermeidet. Das Verfahren soll insbesondere auch geeignet sein zur Ausbesserungslackierung serieniackierter, industriell hergestellter Gegenstände, insbesondere Kraftfahrzeuge und deren Teile, beispielsweise im Rahmen einer bzw, im Anschluß an eine Serienlackierung.The object of the invention is, based on DE-A-197 20 894, an improved method for refinishing Flaws in stove enamels, especially when used stoving paint produced by powder coatings to provide the avoids disadvantages of the prior art described. The procedure is supposed to be particularly suitable for touch-up painting of series-painted, industrially manufactured objects, in particular motor vehicles and their parts, for example in the context of or following a series painting.

Gegenstand der Erfindung ist daher ein Verfahren zur Reparatur von Fehlstellen in einer Einbrennlackierung, das dadurch gekennzeichnet, ist, daß die zur Reparaturlackierung bereite Fehlstelle mit einem Purverlacküberzugsmittel beschichtet wird und der aufgebrachte Pulverlack anschließend durch Bestrahlen mit Nahinfrarot-Strahlung (NIR), die mit NIR-Strahlern erzeugt wird, aufgeschmolzen und ausgehärtet wird.The invention therefore relates to a method for repairing defects in a stove enamel, which is characterized in that the for Faulty areas ready for refinishing are coated with a clearcoat coating agent and the applied powder coating is then irradiated with near infrared radiation (NIR), which is generated with NIR emitters, melted and cured.

Beim erfindungsgemäßen Verfahren werden die ein oder mehreren Fehlstellen innerhalb einer Einbrennlackierung, insbesondere innerhalb einer aus einem Pulverlacküberzugsmittel aufgebrachten Einbrennlackierung unter Verwendung eines Pulverlacküberzugsmittels reparaturlackiert. Bei den Fehlstellen aufweisenden Einbrennlackierungen kann es sich beispielsweise um Einschichtdecklackierungen oder um innerhalb einer mehrschichtigen Lackierung angeordnete Lackschichten handeln, beispielsweise um Grundierungen, Füllerschichten und bevorzugt um äußere, sichtbare farb- und/oder effektgebende oder insbesondere transparente Decklackschichten. Bevorzugt kann das erfindungsgemäße Verfahren eingesetzt werden bei der Reparatur von Fehlstellen innerhalb eingebrannter, aus Pulverlacken, insbesondere Pulverklarlacken erstellter Überzugsschichten. Besonders bevorzugt kann das erfindungsgemäße Verfahren eingesetzt werden bei der Reparatur von Fehlstellen innerhalb von auf Kraftfahrzeuge und deren Teile aufgebrachten Einbrennlackierungen.In the method according to the invention, the one or more defects become within a stove enamelling, especially within one of a Powder coating agent applied stove enamel using a Powder coating agent repainted. In the case of defects Stove enamels can be, for example, single-coat top coats or are paint layers arranged within a multilayer paint system, for example primers, filler layers and preferably outer, visible color and / or effect or in particular transparent Topcoats. The method according to the invention can preferably be used when repairing defects within burned-in powder coatings, especially powder clearcoats of coated layers. Can be particularly preferred the method according to the invention can be used in the repair of defects within applied to motor vehicles and their parts Baking finishes.

Der Ausdruck Fehlstellen bedeutet, daß es sich um lokal begrenzte, beispielsweise bis zu einige Quadratzentimeter große, beispielsweise 1 mm2 bis 100 cm2 große, fehlerhafte Stellen innerhalb von Einbrennlackierungen handelt. Bei den Fehlstellen kann es sich beispielsweise um Beschädigungen wie Kratzer, beispielsweise Montagekratzer, um Beschichtungsstörnngen wie Krater oder Dellen oder um Schmutzeinschlüsse handeln.The term imperfections means that there are locally limited, for example up to a few square centimeters large, for example 1 mm 2 to 100 cm 2 large, defective areas within stoving lacquers. The defects can be, for example, damage such as scratches, for example assembly scratches, coating defects such as craters or dents, or inclusions of dirt.

Es sei darauf hingewiesen, daß die zur Reparaturlackierung eingesetzten Pulverlacküberzugsmittel wäßrige Zubereitungen der Pulverlacküberzugsmittel, sogenannte wäßrige Pulverlackslurries einschließen. Bevorzugt werden im erfindungsgemäßen Verfahren jedoch Pulverlacke selbst eingesetzt.It should be noted that those used for refinishing Powder coating compositions aqueous preparations of powder coating compositions, include so-called aqueous powder coating slurries. Are preferred in However, the process according to the invention uses powder coatings themselves.

Die im erfindungsgemäßen Verfahren als Reparaturlacke eingesetzten Pulverlacke enthalten ein thermisch aushärtbares selbst- oder fremdvernetzendes Bindemittelsystem, bevorzugt eine fremdvemetzende Bindemittel/Härter-Kombination. Unter Bindemittel ist die filmbildende höhermolekulare Komponente eines duroplastischen Pulverlackes zu verstehen, die im allgemeinen mindestens 50 Gew.-% der zugrundeliegenden Bindemittel/Härter-Kombination ausmacht, während die Härterkomponente im allgemeinen maximal 50 Gew.-% innerhalb dieser Kombination beträgt. Die Bindemittelbasis unterliegt keinen prinzipiellen Beschränkungen. Geeignet sind beispielsweise übliche für Pulverlacke eingesetzte Bindemittel. Beispiele sind Polyesterharze, (Meth)acrylcopolymere, Epoxidharze, Phenolharze, Polyurethanharze, Siloxanharze. Die Bindemittel weisen beispielsweise Glasübergangstemperaturen von 30 bis 120°C, bevorzugt unter 90°C, auf und besitzen beispielsweise zahlenmittlere Molmassen (Mn) von 500 bis 20000, bevorzugt unter 10000. Die Härter besitzen z.B. zahlenmittlere Molmassen (Mn) von 84 bis 3000, bevorzugt unter 2000. Es können verschiedene Bindemittel und Härter miteinander gemischt werden.The powder coatings used as refinish coatings in the process according to the invention contain a thermally curable self or externally cross-linking Binder system, preferably a crosslinking binder / hardener combination. Under binder, the film-forming higher molecular component is one thermosetting powder coating, which is generally at least 50% by weight of the underlying binder / hardener combination, while the Hardener component generally a maximum of 50 wt .-% within this combination is. The binder base is not subject to any fundamental restrictions. For example, conventional binders used for powder coatings are suitable. Examples are polyester resins, (meth) acrylic copolymers, epoxy resins, phenolic resins, Polyurethane resins, siloxane resins. The binders have, for example Glass transition temperatures of 30 to 120 ° C, preferably below 90 ° C, on and have, for example, number-average molar masses (Mn) of 500 to 20,000, preferably less than 10,000. The hardeners have e.g. number average molar masses (Mn) from 84 to 3000, preferably less than 2000. Different binders and hardeners can be used be mixed together.

Bindemittel und Härter tragen untereinander komplementär reaktive funktionelle Gruppen, die eine thermische Vernetzungsreaktion des Pulverlackes erlauben, beispielsweise durch Kondensationsreaktionen und/oder Additionsreaktionen. Beispiele für solche funktionelle Gruppen sind Carboxylgruppen, Epoxidgruppen, aliphatisch oder aromatisch gebundene Hydroxylgruppen, Isocyanatgruppen, blockierte Isocyanatgruppen, Anhydridgruppen, primäre oder sekundäre Aminogruppen, geblockte Aminogruppen, zur ringöffnenden Addition befähigte N-heterocyclische Gruppen, wie z.B. Oxazolingruppen, (Meth)acryloylgruppen, CH-acide Gruppen wie z.B. Acetoacetatgruppen.Binders and hardeners have complementary reactive functional functionalities Groups that allow a thermal crosslinking reaction of the powder coating, for example by condensation reactions and / or addition reactions. Examples for such functional groups, carboxyl groups, epoxy groups are aliphatic or aromatically bound hydroxyl groups, isocyanate groups Isocyanate groups, anhydride groups, primary or secondary amino groups, blocked amino groups, N-heterocyclic groups capable of ring-opening addition Groups such as Oxazoline groups, (meth) acryloyl groups, CH-acidic groups such as e.g. Acetoacetate.

Die Auswahl der miteinander reagierenden Gruppen ist dem Fachmann geläufig. Es können gegebenenfalls verschiedene reaktive Gruppen miteinander kombiniert werden. Das kann über Bindemittel geschehen, die verschiedene reaktive funktionelle Gruppen tragen, oder es werden Gemische von unterschiedlichen Härtern und/oder Bindemitteln eingesetzt.The selection of the groups which react with one another is familiar to the person skilled in the art. It can optionally combine different reactive groups with each other become. This can be done using binders that are different reactive functional Wear groups, or mixtures of different hardeners and / or Binders used.

Die verschiedenen funktionellen Gruppen können zugleich am Bindemittel und/oder Härter vorhanden sein. Die Bindemittel sowie auch Härter enthalten im Mittel mindestens 2 funktionelle Gruppen pro Molekül. Das Verhältnis von Bindemittel zu Härter beträgt im allgemeinen beispielsweise 98 : 2 bis 50 : 50. Bevorzugt liegt es zwischen 95 : 5 und 70 : 30.The different functional groups can be on the binder and / or Be harder. The binders and hardeners contain on average at least 2 functional groups per molecule. The ratio of binder to Hardener is generally, for example, 98: 2 to 50:50. It is preferably between 95: 5 and 70: 30.

Beispiele für in Pulverlacken übliche Bindemittel/Härter-Systeme sind Polyesterharze mit niedermolekularen Epoxid- oder Hydroxyalkylamidhärtern, Epoxy/Polyester-Hybridsysteme, Epoxidharze mit Dicyandiamidhärtem, Carbonsäurehärtern oder phenolischen Härtern, hydroxyfunktionelle Polyester oder (Meth)acrylcopolymere mit blockierten Polyisocyanaten, epoxidfunktionelle (Meth)acrylcopolymere mit Carbonsäure- oder Carbonsäureanhydrid-Härtern.Examples of binder / hardener systems customary in powder coatings are polyester resins with low molecular weight epoxy or hydroxyalkylamide hardeners, epoxy / polyester hybrid systems, Epoxy resins with dicyandiamide hardener, carboxylic acid hardeners or phenolic hardeners, hydroxy-functional polyesters or (meth) acrylic copolymers with blocked polyisocyanates, epoxy-functional (meth) acrylic copolymers with Carboxylic acid or carboxylic anhydride hardeners.

Insbesondere im Falle der Reparatur von Fehlstellen in äußeren, sichtbaren, eingebrannten Klarlacküberzügen werden im erfindungsgemäßen Verfahren als Reparaturlacke bevorzugt solche Pulverklarlacke eingesetzt, die als Bindemittel epoxidfunktionelle (Meth)acrylcopolymere, insbesondere Glycidyl(meth)acrylatcopolymere mit einem Epoxidäquivalentgewicht zwischen 250 und 700 und als Härter ein oder mehrere niedermolekulare und/oder polymere Verbindungen mit durchschnittlich 2 oder mehr Carboxylfunktionen pro Molekül und/oder Anhydride davon enthalten. Bevorzugte Härter sind feste aliphatische Dicarbonsäuren und/oder deren Anhydride wie insbesondere Dodecandicarbonsäure, die auch im Gemisch mit carboxylfunktionellen Polyestern verwendet werden können.Especially in the case of the repair of defects in external, visible, baked clear lacquer coatings are in the process according to the invention as Refinish paints are preferably used in powder clearcoats that are used as binders epoxy-functional (meth) acrylic copolymers, in particular Glycidyl (meth) acrylate copolymers with an epoxy equivalent weight between 250 and 700 and one or more low molecular weight and / or polymeric hardeners Compounds with an average of 2 or more carboxyl functions per molecule and / or anhydrides thereof. Solid aliphatic hardeners are preferred Dicarboxylic acids and / or their anhydrides such as in particular dodecanedicarboxylic acid, which can also be used in a mixture with carboxyl-functional polyesters.

Die im erfindungsgemäßen Verfahren eingesetzten Pulverlacke können übliche Pulverlackadditive in üblichen Mengenanteilen von beispielsweise 0,1 bis 5 Gew.-% enthalten. Beispiele für solche Additive sind Verlaufsmittel, Entgasungsmittel wie z.B. Benzoin, Antioxidantien, Lichtschutzmittel, Mattierungsmittel, farb- und/oder effektgebende anorganische und/oder organische Pigmente und/oder Füllstoffe, Farbstoffe, Haftvermittler, Gleitmittel, Katalysatoren sowie rheologiesteuernde Mittel.The powder coating materials used in the process according to the invention can be customary Powder coating additives in the usual proportions of, for example, 0.1 to 5% by weight contain. Examples of such additives are leveling agents, degassing agents such as e.g. Benzoin, antioxidants, light stabilizers, matting agents, color and / or effect-giving inorganic and / or organic pigments and / or fillers, Dyes, adhesion promoters, lubricants, catalysts and rheology control agents.

Werden deckende Pigmente oder Effektpigmente eingesetzt, so handelt es sich um zur Reparatur von Fehlstellen in farb- und/oder effektgebenden Lackschichten einsetzbare Pulverlacküberzugsmittel. Werden keine oder farblose Pigmente, z.B. mikronisiertes Titandioxid oder Siliciumdioxid, eingesetzt, so handelt es sich um zur Reparatur von Fehlstellen in Klarlackschichten einsetzbare Pulverklarlacküberzugsmittel.If opaque pigments or effect pigments are used, they are used for Repair of defects in color and / or effect paint layers can be used Powder paint coating agent. If no or colorless pigments, e.g. micronized Titanium dioxide or silicon dioxide, is used to repair Defects in clear coat layers of powder clearcoat that can be used.

Die Herstellung der im erfindungsgemäßen Verfahren als Reparaturlack eingesetzten Pulverlacke kann nach den üblichen Methoden zur Herstellung von Pulverlacken erfolgen, beispielsweise durch Extrudieren des durch trockenes Mischen aller benötigten Komponenten fertig formulierten Pulverlackes in Form einer pastösen Schmelze, Abkühlen der Schmelze, Grobzerkleinerung, Feinmahlung und gegebenenfalls nachgeschaltetes Sieben auf gewünschte Kornfeinheit, beispielsweise auf mittlere Teilchengrößen von 10 bis 90 µm.The production of the repair paint used in the process according to the invention Powder coatings can be made using the usual methods for producing powder coatings done, for example, by extruding the dry mix of all required components of the formulated powder coating in the form of a pasty Melt, cooling of the melt, coarse comminution, fine grinding and optionally subsequent sieving to the desired fineness, for example to average particle sizes from 10 to 90 µm.

Das erfindungsgemäße Verfahren kann unter Verwendung von feinkörnigem Pulverlack, beispielsweise mit mittleren Teilchengrößen von 1 bis 40 µm durchgeführt werden. Feinkörniger Pulverlack oder Pulverlackfeinkorn kann gezielt hergestellt werden, fällt aber beispielsweise bei der Pulverlackproduktion oder bei der Pulverlackapplikation als an sich unerwünschtes Material an und kann somit im erfindungsgemäßen Verfahren sinnvoll verwendet werden.The process according to the invention can be carried out using fine-grained Powder coating, for example with average particle sizes of 1 to 40 microns become. Fine-grained powder coating or powder coating fine grain can be produced in a targeted manner but falls, for example, in powder coating production or in Powder coating application as an undesirable material per se and can therefore in methods according to the invention can be used sensibly.

Die Pulverlacke können auch als wäßrige Pulverlackslurry verwendet werden. Dazu können sie beispielsweise durch Trocken- oder Naßvermahlung oder durch intensives Dispergieren einer Pulverlackschmelze oder organischen Pulverlacklösung in Wasser in eine wäßrige Pulverlackslurry überführt werden, die gegebenenfalls durch Abdestillieren von organischem Lösemittel befreit werden kann.The powder coatings can also be used as an aqueous powder coating slurry. To you can, for example, by dry or wet grinding or by intensive Disperse a powder coating melt or organic powder coating solution in water be converted into an aqueous powder coating slurry, which if necessary by Organic solvent can be removed by distillation.

Bevorzugt weisen die im erfindungsgemäßen Verfahren eingesetzten Pulverlacke die gleiche Festkörperzusammensetzung auf wie der zuvor zur Herstellung der zu reparierenden, Fehlstellen aufweisenden Einbrennlackschicht eingesetzte Lack. Bevorzugt handelt es sich dabei um eine Reparatur von Fehlstellen in eingebrannten Pulverlackschichten. Dabei werden sowohl bei der Erstlackierung als auch bei der erfindungsgemäßen Reparaturlackierung Pulverlacke mit identischer Zusammensetzung verwendet. Dies ist insbesondere vorteilhaft bei der Reparatur von Fehlstellen in äußeren, sichtbaren, eingebrannten Klarlackschichten. Beispielsweise weichen Eigenfarbe und Brechungsindex von Erst- und Reparaturlackierung dann nicht voneinander ab.The powder coatings used in the process according to the invention preferably have the same solid composition as that previously used to manufacture the repairing varnish with stoving lacquer layer used. This is preferably a repair of defects in the burned-in area Powder coating layers. Both the initial painting and the Repair coating according to the invention powder coatings with identical Composition used. This is particularly advantageous when repairing Defects in outer, visible, baked clear lacquer layers. For example soft intrinsic color and refractive index of the initial and refinishing paint do not differ from each other.

Im erfindungsgemäßen Verfahren werden Fehlstellen in einer Einbrennlackierung unter Verwendung von Pulverlacken als Reparaturlacke repariert. Die Fehlstellen können direkt zur Reparaturlackierung bereit sein oder sie werden zur Reparaturlackierung vorbereitet, beispielsweise durch Schleifen, Fräsen oder Bearbeitung der Fehlstellen mit einem Laser. Im allgemeinen werden die Fehlstellen vor Auftrag des pulverförmigen Reparaturlacks zumindest gereinigt. Außerdem ist es zweckmäßig, die fehlerfrei beschichteten Flächenanteile der Oberfläche vor einer Verunreinigung zu schützen, beispielsweise durch Abdecken, Abkleben oder durch Aufbringung eines Abziehlackes um die zu reparierenden Fehlstellen.In the method according to the invention, imperfections are found in a stove enamelling repaired using powder coatings as refinish. The missing parts can be ready for refinishing directly or they will be used Prepared refinish, for example by grinding, milling or Machining the defects with a laser. Generally the flaws at least cleaned before applying the powdered refinish. Besides, it is Appropriately, the flawlessly coated surface portions of the surface in front of one To protect contamination, for example by covering, masking or by Applying a peeling varnish around the defects to be repaired.

Die zur Reparaturlackierung bereiten Fehlstellen können unabhängig davon, ob sie sich auf horizontalen oder vertikalen Flächen befinden mit dem Pulverlacküberzugsmittel beschichtet werden, beispielsweise mechanisch, beispielsweise durch Aufstreuen, Aufbürsten oder Aufpinseln oder die Applikation erfolgt durch Aufspritzen mit den dafür üblichen Applikationseinrichtungen. Das mechanische Aufbringen eignet sich insbesondere für feinkörniges Pulverlackmaterial. Das Aufspritzen kann beispielsweise elektrostatisch unterstützt erfolgen, z.B. mit Hilfe von Corona- oder Tribo-Sprühorganen.The defects that are ready for refinishing can be irrespective of whether they are on horizontal or vertical surfaces with the Powder coating agents are coated, for example mechanically, for example by sprinkling, brushing or brushing or application is carried out by spraying with the usual application equipment. The mechanical application is particularly suitable for fine-grained powder coating material. The spraying can be carried out, for example, with electrostatic assistance, e.g. With With the help of corona or tribo spray organs.

Im erfindungsgemäßen Verfahren wird nach der Applikation des Pulverlacks oder nach Applikation und Trocknung der wäßrigen Pulverlackslurry die auf die Fehlstelle aufgebrachte Pulverlackzusammensetzung durch Bestrahlen mit NIR-Strahlung, bevorzugt mit NIR-Strahlung hoher Intensität, aufgeschmolzen und ausgehärtet. Bei MR-Strahlung handelt es sich um kurzwellige Infrarot-Strahlung des Wellenlängenbereichs von etwa 760 bis etwa 1500 nm, bevorzugt 760 bis 1200 nm. Erfindungsgemäß werden übliche energiereuhe NIR-Strahler verwendet die flächig, oder linien- oder punktförmig fokussiert abstrahlen können. Derartige NIR-Strahler sind kommerziell erhältlich (beispielsweise von der Firma Industrie SerVis). Es handelt sich beispielsweise um Hochleistungshalogenstrahler mit einer Strahlungsdichte von im allgemeinen mehr als 1 W/cm2, bevorzugt mehr als 10 W/cm2, bis beispielsweise 15 MW/m2. Die Strahler erreichen beispielsweise eine Strahleroberflächentemperatur (Glühwendeltemperatur) zwischen 2000 und 3000 K. Geeignete Strahler weisen beispielsweise ein Emissionsspektrum mit einem Maximum zwischen 750 und 1200 nm auf.In the process according to the invention, after the application of the powder coating or after application and drying of the aqueous powder coating slurry, the powder coating composition applied to the defect is melted and cured by exposure to NIR radiation, preferably high-intensity NIR radiation. MR radiation is short-wave infrared radiation in the wavelength range from approximately 760 to approximately 1500 nm, preferably 760 to 1200 nm. Such NIR emitters are commercially available (for example from Industrie SerVis). These are, for example, high-performance halogen lamps with a radiation density of generally more than 1 W / cm 2 , preferably more than 10 W / cm 2 , for example up to 15 MW / m 2 . The emitters, for example, reach an emitter surface temperature (filament temperature) of between 2000 and 3000 K. Suitable emitters, for example, have an emission spectrum with a maximum between 750 and 1200 nm.

Der Bestrahlungszeitraum beträgt im erfindungsgemäßen Verfahren beispielsweise 1 bis 300 Sekunden. Bei der Bestrahlung schmilzt der zur Ausbesserung der Fehlstelle aufgebrachte Pulverlack auf und härtet zum Beispiel innerhalb von 1 bis 300 Sekunden, bevorzugt innerhalb von 5 bis 60 Sekunden aus.The irradiation period in the method according to the invention is, for example, 1 up to 300 seconds. When irradiated, it melts to repair the defect applied powder coating and hardens, for example, within 1 to 300 Seconds, preferably within 5 to 60 seconds.

Die Bestrahlung kann in einer mit einem oder mehreren NIR-Strahlern ausgerüsteten Bandanlage oder mit einem NIR-Strahler, der vor dem zu bestrahlenden Objekt bzw. der zu bestrahlenden Stelle positioniert wird, durchgeführt werden.The radiation can be equipped with one or more NIR emitters Conveyor system or with a NIR emitter that is in front of the object to be irradiated or the position to be irradiated is carried out.

Die erstgenannte Möglichkeit bietet sich beispielsweise an bei der Reparaturlackierung von Einzelteilen oder von Objekten, bei denen in einem Schritt mehrere Fehlstellen repariert werden sollen. Dabei können die Bandgeschwindigkeit und damit die Bestrahlungsdauer variiert werden. Beispielsweise können Bandgeschwindigkeiten von 1 bis 7 m/min eingestellt werden, was beispielsweise Bestrahlungszeiten von 2 bis 20 Sekunden entsprechen kann. Der Abstand zwischen NIR-Strahler und Objektoberfläche kann z.B. 1 bis 60 cm, bevorzugt 4 bis 20 cm betragen.The first option is available, for example, for refinishing of individual parts or objects in which several defects are present in one step to be repaired. The belt speed and thus the Irradiation time can be varied. For example, belt speeds of 1 to 7 m / min can be set, which for example irradiation times from 2 to 20 Seconds. The distance between the NIR emitter and Object surface can e.g. 1 to 60 cm, preferably 4 to 20 cm.

Bei der zweiten Möglichkeit wird der NIR-Strahler vor dem zu bestrahlenden Objekt bzw. der zu bestrahlenden Stelle positioniert. Die Bestrahlungsdauer kann z.B. 1 bis 300 Sekunden betragen, der Objektabstand z.B. 1 bis 60 cm, bevorzugt 4 bis 20 cm. In the second option, the NIR emitter is placed in front of the object to be irradiated or the position to be irradiated. The radiation duration can e.g. 1 to 300 seconds, the object distance e.g. 1 to 60 cm, preferably 4 to 20 cm.

Die verschiedenen Bestrahlungsparameter, wie Bandgeschwindigkeit bzw. Bestrahlungsdauer, Objektabstand, Strahlungsleistung des verwendeten NIR-Strahlers können vom Fachmann entsprechend den Bedürfnissen der jeweiligen Reparaturaufgabe angepaßt werden.The different radiation parameters, such as belt speed or Irradiation time, object distance, radiation power of the NIR emitter used can by the specialist according to the needs of each Repair task to be adjusted.

Es ist auch möglich zur Aushärtung eine Kombination aus NIR-Bestrahlung und Wärmezufuhr mittels konventionellen Wärmequellen wie Konvektionsöfen oder gewöhnlichen längerwelligen Infrarotstrahlern einzusetzen.It is also possible to use a combination of NIR radiation and curing Heat supply using conventional heat sources such as convection ovens or use ordinary longer-wave infrared radiators.

Nach der Aushärtung des zur Ausbesserung von Fehlstellen aufgebrachten Pulverlacks durch NIR-Bestrahlung kann es zweckmäßig sein, die reparierte Stelle zu glätten, beispielsweise durch Polieren.After the powder coating applied to repair defects has hardened by means of NIR radiation, it may be expedient to smooth the repaired area, for example by polishing.

Mit dem erfindungsgemäßen Verfahren können Fehlstellen in einschichtigen Einbrennlackierungen repariert werden. Ebenso können mit dem erfindungsgemäßen Verfahren auch Fehlstellen in einer innerhalb einer Mehrschichtlackierung angeordneten Einbrennlackschicht repariert werden. Dabei können zumindest zwei Fälle unterschieden werden:

  • 1. Applikation einer oder mehrerer unterer (substratnäherer) Lackschichten, gegebenenfalls Trocknung oder Härtung dieser, erfindungsgemäße Applikation von Pulverreparaturlack (oder wäßriger Pulverreparaturlackslurry), Aufschmelzen und Aushärtung der (getrockneten) Pulverlackschicht durch NIR-Bestrahlung, gegebenfalls Überlackierung mit weiteren Überzugsschichten. Beispielsweise im Falle einer zu reparierenden Fehlstelle innerhalb einer Klarlackschicht einer farb- und/oder effektgebenden Basislack-Klarlack-Zweischichtlackierung kann zunächst die farb- und/oder effektgebende Basislackschicht aus einem Basislacküberzugsmittel auf die zur Reparaturlackierung bereite Fehlstelle der Einbrennlackierung aufgetragen, gegebenenfalls abgelüftet und/oder eingebrannt und danach ein Pulverklarlack aufgebracht und durch NIR-Bestrahlung aufgeschmolzen und ausgehärtet werden.
  • 2. Erfindungsgemäße Applikation von Pulverreparaturlack (oder Pulverreparaturlackslurry), Aufschmelzen und Aushärtung der (getrockneten) Pulverlackschicht durch NIR-Bestrahlung, gegebenfalls Überlackierung mit weiteren Überzugsschichten. Beispielsweise im Falle einer zu reparierenden Fehlstelle innerhalb einer Füllerschicht wird ein Pulverfüller aufgebracht und durch NIR-Bestrahlung aufgeschmolzen und ausgehärtet, bevor beispielsweise mit Basislack und Klarlack überlackiert wird. Beispielsweise kann das Überlackieren mit Basislack und Klarlack im Rahmen der Erstlackierung oder im Rahmen einer Reparaturlackierung am fertig erstlackierten Objekt stattfinden. Ein anderes Beispiel ist eine zu reparierende Fehlstelle innerhalb einer Klarlackschicht einer farb- und/oder effektgebenden Basislack-Klarlack-Zweischichtlackierung. Hier kann auf die zur Reparatur bereite Fehlstelle, beispielsweise eine nicht bis auf die Basislackschicht oder noch tiefer ausgeschliffene Fehlstelle ein Pulverklarlack aufgebracht und durch NIR-Bestrahlung aufgeschmolzen und ausgehärtet werden.
    • With the method according to the invention, defects in single-layer stove enamels can be repaired. Defects in a stoving lacquer layer arranged within a multi-layer coating can also be repaired with the method according to the invention. At least two cases can be distinguished:
  • 1. Application of one or more lower (closer to the substrate) lacquer layers, optionally drying or hardening them, application of powder repair lacquer (or aqueous powder repair lacquer slurry) according to the invention, melting and hardening of the (dried) powder lacquer layer by NIR radiation, optionally overcoating with further coating layers. For example, in the event of a defect to be repaired within a clear lacquer layer of a color and / or effect basecoat-clearcoat two-layer coating, the color and / or effect basecoat layer can first be applied from a basecoat coating agent to the defect in the stoving lacquer ready for refinishing, if necessary ventilated and / or baked and then a clear powder coating is applied and melted and cured by NIR radiation.
  • 2. Application of powder repair lacquer (or powder repair lacquer slurry) according to the invention, melting and curing of the (dried) powder lacquer layer by NIR radiation, optionally overpainting with further coating layers. For example, in the case of a defect to be repaired within a filler layer, a powder filler is applied and melted and hardened by NIR radiation before, for example, overcoating with basecoat and clearcoat. For example, overpainting with basecoat and clearcoat can take place as part of the initial painting or as part of a refinish on the object that has already been painted. Another example is a defect to be repaired within a clear coat of a color and / or effect basecoat-clearcoat two-coat system. Here, a powder clear coat can be applied to the flaw that is ready for repair, for example a flaw that is not ground down to the basecoat layer or deeper, and melted and cured by NIR radiation.

    • Das erfindungsgemäße Verfahren gestattet die Reparaturlackierung von Fehlstellen in Einbrennlackierungen, insbesondere innerhalb von unter Verwendung von Pulverlacken hergestellten Einbrennlackierungen. Die eingangs beschriebenen Nachteile des Standes der Technik können vermieden werden. Das Verfahren ist geeignet zur Ausbesserungslackierung serienlackierter, industriell hergestellter Gegenstände, insbesondere ist es geeignet zur Reparatur von Fehlstellen innerhalb von im Rahmen der Automobil- oder Automobilteileserienlackierung erzeugten Pulverlackschichten, insbesondere Pulverdeck- und Pulverklarlackschichten.The method according to the invention permits the refinishing of defects in Stove enamels, especially within using Powder coatings produced stove enamels. The ones described at the beginning Disadvantages of the prior art can be avoided. The procedure is suitable for touch-up painting of mass-produced, industrially manufactured Items, in particular it is suitable for repairing imperfections within generated in the context of automotive or automotive parts series painting Powder coating layers, in particular powder topcoat and powder clearcoat layers.

    Beispielexample

    Auf einer Motorhaube mit einem typischen Serienlackierungsaufbau aus kathodisch abgeschiedener Grundierung, Füller-, Basislack- und abschließender Pulverklarlackschicht befindet sich ein Schmutzpartikel innerhalb der Pulverklarlackschicht. On a bonnet with a typical serial painting structure made of cathodic deposited primer, filler, basecoat and final There is a dirt particle inside the powder clear coat Powder clear coat layer.

    Das Schmutzpartikel wird durch Schleifen beseitigt, ohne in die Basislackschicht einzudringen. Es entsteht eine ca. 0,5 cm2 große, zur Reparatur bereite Fehlstelle in der Pulverklarlackschicht. Der zu reparierende Bereich wird von der fehlerfreien Oberfläche durch Abkleben mit hitzeslabiler Folie abgegrenzt.The dirt particle is removed by sanding without penetrating the basecoat. An approx. 0.5 cm 2 defect in the powder clear coat layer ready for repair is created. The area to be repaired is separated from the flawless surface by masking with heat-unstable film.

    Auf die zur Reparatur bereite Fehlstelle wird durch elektrostatisches Spritzen der gleiche Pulverklarlack aufgetragen, wie der zuvor zur Herstellung der Erstlackierung eingesetzte Pulverklarlack.The defect that is ready for repair is removed by electrostatic spraying same powder clearcoat applied as that used to produce the first coat powder clearcoat used.

    Im Abstand von 100 mm von der mit Pulverklarlack beschichteten Fehlstelle wird ein NIR-Strahler der Fa. Industrie SerVis positioniert. Es wird 8 Sekunden mit einer Leistung von 400 kW/m2 bestrahlt, innerhalb derer der Pulverklarlack aufschmilzt und vollständig aushärtet.An NIR emitter from Industrie SerVis is positioned at a distance of 100 mm from the flaw coated with powder clear lacquer. It is irradiated for 8 seconds with a power of 400 kW / m 2 , within which the powder clear lacquer melts and hardens completely.

    Anschließend wird die Abdeckfolie entfernt und die reparierte Stelle wird unter Verwendung einer handelsüblichen Schleifpaste kleinflächig poliert.Then the cover film is removed and the repaired area is under Use a commercially available grinding paste, polished over a small area.

    Claims (9)

    1. Process for the repair of defects in a stoved enamel, wherein the defect ready for refinishing is coated with a powder coating compound or an aqueous powder coating slurry and the applied powder coating is then melted and cured by irradiation with near infrared radiation (NIR), generated by NIR radiators.
    2. Process according to claim 1, characterised in that it is performed to repair defects within stoved coatings produced from powder coatings.
    3. Process according to claim 1 or 2, characterised in that it is performed to repair defects within stoved enamels applied to motor vehicles and components thereof.
    4. Process according to one of claims 1 to 3, characterised in that it is performed to repair defects in external, visible, stoved clear coats.
    5. Process according to one of claims 1 to 4, characterised in that the defects are prepared for refinishing, in particular by grinding, milling, machining the defects with a laser and/or cleaning.
    6. Process according to one of claims 1 to 5, characterised in that irradiation takes place with NIR radiation in the wavelength range from 760 to 1500 nm.
    7. Process according to one of claims 1 to 6, characterised in that NIR radiators are used which can radiate with a plane, linear or point-like focus for adjustment to the defect to be repaired.
    8. Process according to one of claims 1 to 7, characterised in that the NIR irradiation is performed in combination with conventional heat sources.
    9. Process according to one of claims 1 to 8, characterised in that it is performed with a powder coating or an aqueous powder coating slurry displaying the same solids composition as the lacquer previously used to produce the stoved enamel coating displaying defects to be repaired.
    EP00938741A 1999-06-14 2000-06-05 Method for refinishing defects in stoved enamels with powder coatings Expired - Lifetime EP1192013B1 (en)

    Applications Claiming Priority (3)

    Application Number Priority Date Filing Date Title
    DE19927041A DE19927041A1 (en) 1999-06-14 1999-06-14 Process for refinishing defects in stoving paints with powder coatings
    DE19927041 1999-06-14
    PCT/EP2000/005092 WO2000076678A2 (en) 1999-06-14 2000-06-05 Method for refinishing defects in stoved enamels with powder coatings

    Publications (2)

    Publication Number Publication Date
    EP1192013A2 EP1192013A2 (en) 2002-04-03
    EP1192013B1 true EP1192013B1 (en) 2003-10-01

    Family

    ID=7911158

    Family Applications (1)

    Application Number Title Priority Date Filing Date
    EP00938741A Expired - Lifetime EP1192013B1 (en) 1999-06-14 2000-06-05 Method for refinishing defects in stoved enamels with powder coatings

    Country Status (8)

    Country Link
    US (1) US7018682B1 (en)
    EP (1) EP1192013B1 (en)
    JP (1) JP2003501260A (en)
    AT (1) ATE250985T1 (en)
    AU (1) AU5401100A (en)
    DE (2) DE19927041A1 (en)
    ES (1) ES2203485T3 (en)
    WO (1) WO2000076678A2 (en)

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    US6280800B1 (en) * 2000-01-18 2001-08-28 E. I. Du Pont De Nemours And Company Process for coating metallic substrate surfaces
    US6743466B2 (en) * 2001-08-03 2004-06-01 E. I. Du Pont De Nemours And Company Process for repairing coated substrate surfaces
    US20040219385A1 (en) * 2002-08-23 2004-11-04 Rene Mattern Process for curing powder coatings
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    Also Published As

    Publication number Publication date
    JP2003501260A (en) 2003-01-14
    US7018682B1 (en) 2006-03-28
    WO2000076678A2 (en) 2000-12-21
    WO2000076678A3 (en) 2001-08-02
    DE19927041A1 (en) 2000-12-21
    ES2203485T3 (en) 2004-04-16
    ATE250985T1 (en) 2003-10-15
    DE50003913D1 (en) 2003-11-06
    AU5401100A (en) 2001-01-02
    EP1192013A2 (en) 2002-04-03

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