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

Definitions

• the present invention relates to a method for producing a multi-layer refinish coating, in which
• the old paint is prepared by cleaning, sanding and, if necessary, applying a filler and / or filler material
• an aqueous base coating composition containing metal pigments and / or effect pigments is applied by spray application
• a polymer film is formed from the composition applied in step (2),
• the top layer is then dried together with the base layer at temperatures of up to 140 ° C., preferably at temperatures below 100 ° C. and particularly preferably at temperatures from 60 to 80 ° C.
• the substrates that can be used for refinishing are either old paint (factory paint or refinish), primed new parts (mostly ETL-primed, especially in the area of painting truck bodies) as well as steel, aluminum, galvanized sheet metal or plastic.
• old paint factory paint or refinish
• primed new parts mostly ETL-primed, especially in the area of painting truck bodies
• steel aluminum, galvanized sheet metal or plastic.
• suitable paint materials and the process used for the production of a refinish depends on the surface to be painted and the customer's requirements.
• a multilayer refinish coating is usually produced by thoroughly cleaning the damaged area, sanding, if necessary filling and applying a repair filler to the area to be coated. In the case of full coatings, the appropriate pretreatment of the entire old coating to be coated is carried out. The surface prepared in this way is then painted.
• the production of metallic refinish paints is problematic, since the color and brightness of the effect strongly depend on the processing.
• the nozzle width of the spray gun and the spray pressure play a decisive role.
• the type of dilution and the spray viscosity also influence the color and effect. Cloud formation and similar effects are frequently observed, in particular when aqueous base coating compositions are used.
• the present invention was therefore the object
• aqueous base coating composition is applied until a limit is reached on the prepared surface of the old paint
• step (a) the surface of the old coating coated in step (a) is then coated in a further spraying step with the aqueous base coating composition
• step (c) the process step (c) is carried out until the entire part to be coated is provided with a base layer.
• the process according to the invention can be used to obtain refinish coatings in which the problems which usually occur are avoided or at least significantly reduced.
• the cloud formation frequently observed in the conventional repair methods is avoided. It is important that these excellent results can also be achieved using aqueous metallic basecoats.
• Another advantage is the time saved, which is due to the fact that there is only a short flash-off time between the first and second spraying steps, and particularly preferably no flash-off time at all.
• the method according to the invention for producing a multi-layer refinish coating can be used on a wide variety of substrates. It is irrelevant whether it is conventional or water-dilutable structures that are to be provided with the repair paint.
• the old paint is first prepared to receive the repair paint, usually the old paint is first cleaned thoroughly, e.g. with a silicone remover and roughened with abrasive paste or sandpaper. Thereafter, the surface thus treated is usually cleaned and degreased again.
• a silicone remover and roughened with abrasive paste or sandpaper.
• the surface thus treated is usually cleaned and degreased again.
• an aqueous or water-thinnable or conventional coating agent can then be applied to the correspondingly prepared old coating.
• highly thinned clear lacquers are usually applied, which can be both aqueous, water-dilutable and conventional.
• pre-drying must be carried out before the basecoat is applied; this is usually done by heating the clear coat to a temperature below 140 ° C., preferably below 80 ° C., for a period of 5 -60 min.
• aqueous coating agents are used for this process step, a baking step may be omitted and after a short flash-off time of 5-50 min. directly the basecoat Composition can be applied.
• the old coating is pre-sprayed with such a clear lacquer, it may be possible to dispense with grinding the old coating. Usually, however, the pretreatment of the old paint described above is carried out by cleaning and sanding.
• Aqueous clearcoats suitable for this pretreatment of the old coating are described, for example, in DE-OS-40 09 000.
• the conventional clear lacquers usually used for this purpose such as those sold by Glasurit GmbH, can also be used.
• the aqueous base coating composition is first applied to the prepared old paint in a first spraying step until a limit is reached. Subsequently, the aqueous basecoat composition is applied directly (ie without intermediate drying) to the previously coated parts of the old coating in a second spraying step, again until the limit is reached.
• the entire roof of a car is first coated with the aqueous base coating composition in a first spraying step. The roof is then coated directly with the aqueous base coating composition in a second spraying step.
• the area of the old paint which is adjacent to the previously coated area of the old paint, is again coated with the aqueous base coating composition in two successive spray passes until a limit is reached in accordance with the previous statements.
• a fender of the car is first coated with the aqueous base coating composition in two successive spray passes.
• Process step (c) described above is carried out until the entire part to be coated is provided with a base layer.
• This process step of part-by-part coating with the base coating composition is repeated until the entire part to be coated is coated with the base layer.
• flash-off time of less than 30 min, particularly preferably a flash-off time of less than 20 min, between the first spray coat of the base coating composition and the subsequent second spray coat of the aqueous base coating composition. It is very particularly preferred to work between the first and the second spraying cycle without flash-off time.
• the application of the base coating composition is carried out under the usual conditions. This means that, for example, a normal or only a slightly reduced spray gun pressure is used.
• the spray gun inlet pressure is preferably between 3.0 and 4.5 bar.
• the spray gun outlet pressure varies depending on the one used
• Spray gun When using a HVLP (high volume, low pressure) gun, it is, for example, between 0.6 and 0.7 bar. All spray guns usually used for the application of basecoats are suitable for the application of the basecoat composition, for example the above-mentioned HVLP guns, but also normal pneumatic high-performance spray guns (e.g. SATA-Jet 1.4E).
• HVLP high volume, low pressure
• All spray guns usually used for the application of basecoats are suitable for the application of the basecoat composition, for example the above-mentioned HVLP guns, but also normal pneumatic high-performance spray guns (e.g. SATA-Jet 1.4E).
• aqueous base coating compositions which normally contain metal and / or effect pigments and are used for refinishing.
• Base coating compositions which contain at least one polyurethane resin as a binder are particularly suitable.
• the aqueous base coating compositions described in DE-OS-40 09 000 are suitable.
• the aqueous basecoat compositions prepared using a mixing system are also suitable.
• a suitable transparent top coat is applied to the base layer
• the dry film layer thickness of the cover layer is generally between 30 and 100 ⁇ m.
• the dry film layer thickness of the base layer is generally between 10 and 25 ⁇ m.
• the cover layer is then optionally together with the base layer at temperatures of up to 140 ° C., preferably at temperatures below 100 ° C., and particularly preferably at temperatures from 60 to 80 ° C dried for 5-120 min.
• a wide variety of substrates can be used as the substrate for the production of the multilayer refinish according to the invention, such as B. old paintwork (factory painting or refinishing primed) and primed new parts (mostly ETL primed, especially in the area of painting truck bodies).
• B. old paintwork factory painting or refinishing primed
• primed new parts mostly ETL primed, especially in the area of painting truck bodies.
• the process is used for whole-part refinishing.
• An electro-primed steel sheet serves as the substrate, which is coated with a commercially available, conventional filler material based on a melamine-crosslinked polyester resin (FC60-7133 from BASF Lacke + Weg, Weg; dry film thickness 40 ⁇ m), a commercially available, conventional metal base paint Based on cellulose acetobutyrate (AE54-9153 from BASF Lacke + Weg, Weg; dry film thickness 15 ⁇ m) and a conventional clearcoat based on isocyanate-crosslinked hydroxyl-containing acrylates (AF23-0185 from BASF Lacke + Weg, Weg; dry film thickness 60 ⁇ m) is provided.
• the coated sheet is additionally stored for several hours at an elevated temperature, for example 60 ° C, and the coating is thus aged.
• the old paintwork simulated in this way is first cleaned, then roughened with sandpaper and again cleaned.
• the commercially available 1-component primer Glassohyd® 76-86W from BASF Lacke + Maschinen AG, Weg, is then applied to the old paint prepared in this way with 2 spray passes in 2 spray passes and dried at 60 ° C for 30 min.
• the aqueous commercially available repair basecoat VW mintmet is then applied. VWL-B6 / 00U from BASF Lacke + Maschinen AG, Weg (dry film thickness 15 ⁇ m).
• the application is carried out by means of the HVLP spray gun (High Volume Low Pressure) spray gun SATA Jet B NR92
• the base layer is then dried for 10 minutes at 60 ° C. and allowed to cool for 5 minutes.
• the commercially available 2-component clear lacquer based on isocyanate-crosslinked acrylate-containing acrylates (AF 23-0185 plus SC 29-0173) is then applied to the base layer plus SV 41-0391 from BASF Lacke + Weg, Weg; mixing ratio 2: 1: 0.6) is applied, the clearcoat being applied with a dry film thickness of 60 ⁇ m and after a short flash-off time of 5 min then the top layer was dried at 60 ° C. for 30 minutes.
• the coating obtained in this way shows excellent surface properties.
• the one obtained Coating Advantages in terms of cloud formation compared to coatings in which the entire car body is first coated with the MetaUicbasisIack in one spray pass and the basecoat is only applied to the entire body in a second spray pass after the entire body has been finished .

Landscapes

• Application Of Or Painting With Fluid Materials (AREA)
• Paints Or Removers (AREA)
• Coating With Molten Metal (AREA)
• Road Signs Or Road Markings (AREA)

Applications Claiming Priority (3)

Publications (2)

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Family Applications (1)

Country Status (9)

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• 1993
  • 1993-11-20 DE DE4339612A patent/DE4339612A1/de not_active Withdrawn
• 1994
  • 1994-11-12 US US08/649,647 patent/US5871809A/en not_active Expired - Fee Related
  • 1994-11-12 DK DK95900722T patent/DK0729390T3/da active
  • 1994-11-12 EP EP95900722A patent/EP0729390B1/fr not_active Expired - Lifetime
  • 1994-11-12 ES ES95900722T patent/ES2124517T3/es not_active Expired - Lifetime
  • 1994-11-12 BR BR9408088A patent/BR9408088A/pt not_active IP Right Cessation
  • 1994-11-12 DE DE59406940T patent/DE59406940D1/de not_active Expired - Lifetime
  • 1994-11-12 AT AT95900722T patent/ATE171090T1/de active
  • 1994-11-12 JP JP7514792A patent/JPH09506292A/ja active Pending
  • 1994-11-12 WO PCT/EP1994/003755 patent/WO1995014540A1/fr active IP Right Grant

Non-Patent Citations (1)

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