EP1032475A1 - Method for multi-layered coating of substrates - Google Patents

Method for multi-layered coating of substrates

Info

Publication number
EP1032475A1
EP1032475A1 EP98961139A EP98961139A EP1032475A1 EP 1032475 A1 EP1032475 A1 EP 1032475A1 EP 98961139 A EP98961139 A EP 98961139A EP 98961139 A EP98961139 A EP 98961139A EP 1032475 A1 EP1032475 A1 EP 1032475A1
Authority
EP
European Patent Office
Prior art keywords
meth
coating
basecoat
radiation
binders
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.)
Ceased
Application number
EP98961139A
Other languages
German (de)
French (fr)
Inventor
Karin Maag
Helmut Löffler
Werner Lenhard
Christine Kurz
Frank-Jürgen Krumpolt
Volker Rekowski
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
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from DE1997151479 external-priority patent/DE19751479A1/en
Priority claimed from DE1997157083 external-priority patent/DE19757083A1/en
Application filed by EI Du Pont de Nemours and Co filed Critical EI Du Pont de Nemours and Co
Publication of EP1032475A1 publication Critical patent/EP1032475A1/en
Ceased legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D175/00—Coating compositions based on polyureas or polyurethanes; Coating compositions based on derivatives of such polymers
    • C09D175/04—Polyurethanes
    • C09D175/14—Polyurethanes having carbon-to-carbon unsaturated bonds
    • C09D175/16—Polyurethanes having carbon-to-carbon unsaturated bonds having terminal carbon-to-carbon unsaturated bonds
    • 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
    • B05D3/06—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 exposure to radiation
    • B05D3/061—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 exposure to radiation using U.V.
    • B05D3/065—After-treatment
    • B05D3/067—Curing or cross-linking the coating
    • 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
    • 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
    • B05D7/53—Base coat plus clear coat type
    • 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
    • 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
    • B05D7/56—Three layers or more
    • B05D7/57—Three layers or more the last layer being a clear coat

Definitions

  • the invention relates to a method for multi-layer painting of substrates with a coloring and / or effect basecoat and a clear coat, which is used in particular in the field of vehicle and vehicle parts painting and in particular for refinishing.
  • Multi-layer vehicle refinishes generally consist of one
  • Basecoat / clearcoat topcoat which is applied to substrates which may have been precoated with primers, fillers or other coating agents.
  • EP-A-000 407 describes radiation-curable coating compositions based on an OH-functional polyester resin esterified with acrylic acid, one Vinyl compound, a photoinitiator and a polyisocyanate.
  • a 1st hardening step the radiation is hardened by means of UV light and in a 2nd hardening step the coating gets its final hardness through the OH / NCO crosslinking.
  • the second curing step can take place at 130 - 200 ° C or over several days at room temperature.
  • EP-A-540 884 describes a process for the production of a multi-layer coating for automotive serial painting by applying a clear coat on a dried or hardened basecoat layer, the clearcoat coating agent containing curable binders by free-radical and / or cationic polymerization, and the curing being carried out by means of high-energy radiation becomes. After the clear layer has been irradiated, the stoving process takes place, the basecoat and clearcoat being used together in e.g. 80 - 160 C.
  • EP-A-247 563 describes clearcoats curable by means of UV radiation
  • ⁇ oly (meth) acryloyl-functional compound a polyol mono (meth) acrylate, a polyisocyanate, a light stabilizer and a photoinitiator.
  • Some of the radiation-curable binders here also contain hydroxyl functions which can react with the polyisocyanate present and offer an additional curing option.
  • US-A-4 668 529 describes a UV-curable 1K filler coating agent for refinishing.
  • the binder is based on tripropylene glycol triacrylate and trimethylpropane triacrylate.
  • an epoxy resin based on a bisphenol A diglycidyl ether is included.
  • the object of the invention was to provide a method for producing a multilayer coating, in particular refinishing coating, which enables a significant reduction in the solvent emission in the overall structure and has short drying times.
  • very good water resistance and hardness as well as very good interlayer adhesion and resistance to dissolving of the basecoat with respect to the lacquer layers below and above should be guaranteed.
  • the object is achieved by a process for producing a multilayer coating, in which a coloring and / or effect-imparting basecoat coating agent is applied to a substrate which may have been pre-coated with a primer and / or filler coating agent and / or further coating agents, and then onto the coloring and / or effect-imparting basecoat layer, a clearcoat layer is applied, characterized in that the coloring and / or effect-imparting basecoat coating agent used is one which contains, under the action of high-energy radiation, binders curable by free-radical and / or cationic polymerization.
  • the multi-layer coatings obtained with the process according to the invention show the same high level of properties required for a coating, in particular a refinishing coating, with respect to properties such as hardness, scratch resistance, water and chemical resistance as multi-layer coatings which were created with the basecoat / clearcoat layers customary for vehicle (repair) painting. It was also surprising that various properties, e.g. Interlayer adhesion, resistance to dissolving against layers of paint above or below, resistance to fuel, tree resin and pancreatin, could still be significantly improved.
  • the color and / or effect basecoats which can be used in the process according to the invention are coating compositions which crosslink by means of high-energy radiation via free-radical and / or cationic polymerization.
  • These can be aqueous systems with a high solids content, for example with a solids content of 50 to 95% by weight, which are present as an emulsion, but the systems can also be in a solvent-containing form. However, it can also be a 100% coating agent that can be applied without solvent and without water.
  • Basecoats which can be used according to the invention can be all of the customary radiation-curable binders or mixtures thereof which are known to the person skilled in the art and are described in the literature. They are either binders which can be crosslinked by free-radical polymerization or by cationic polymerization. In the former, radicals are generated by the action of high-energy radiation on the photoinitiators, which then trigger the crosslinking reaction. In the case of the cationically curing systems, Lewis acids are formed by the irradiation from initiators, which in turn trigger the crosslinking reaction.
  • the free-radically curing binders can e.g. to prepolymers or
  • Act oligomers which have free-radically polymerizable olefinic double bonds in the molecule.
  • prepolymers or oligomers are (meth) acrylic-functional (meth) acrylic copolymers, epoxy resin (meth) acrylates, polyester (meth) acrylates, polyether (meth) acrylates, polyurethane (meth) acrylates,, amino (meth) acrylates, silicone (meth) acrylates, melamine (meth) acrylates, unsaturated
  • Polyurethane or unsaturated polyester are Polyurethane or unsaturated polyester.
  • the number average molecular weight (Mn) of these compounds is preferably from 200 to 10,000.
  • the binders can be used individually or in a mixture.
  • the prepolymers can be used in combination with reactive diluents, i.e. reactive polymerizable liquid monomers.
  • the reactive diluents are generally used in amounts of 1-50% by weight, preferably 5-30% by weight, based on the total weight of prepolymer and reactive diluent.
  • the reactive diluents can be mono-, di- or polyunsaturated. Examples of monounsaturated reactive diluents are: (meth) acrylic acid and its esters,
  • unsaturated reactive diluents are: di (meth) acrylates such as alkylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, vinyl (meth) acrylate, allyl (meth) acrylate, divinylbenzene, dipropylene glycol di (meth) acrylate, hexanediol di (meth) acrylate.
  • di (meth) acrylates such as alkylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, vinyl (meth) acrylate, allyl (meth) acrylate, divinylbenzene, dipropylene glycol di (meth) acrylate, hexanediol di (meth) acrylate.
  • polyunsaturated reactive diluents are: glycerol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate.
  • the reactive diluents can be used individually or in a mixture.
  • Diacrylates such as dipropylene glycol diacrylate, tripropylene glycol diacrylate and / or hexanediol diacrylate are preferably used as reactive diluents.
  • binders known to the person skilled in the art and described in the literature can be used as binders for cationically polymerizable systems.
  • These can be, for example, polyfunctional epoxy oligomers which contain more than two epoxy groups in the molecule.
  • Glycidyl ether epoxy urethane resins, glycerol triglycidyl ether,
  • the number average molecular weight (Mn) of the polyepoxide compounds is preferably less than 10,000.
  • Reactive diluents such as e.g. Cyclohexene oxide, butene oxide, butanediol diglycidyl ether or hexanediol diglycidyl ether can be used.
  • the binder systems curing under the action of radiation contain photoinitiators.
  • Suitable photoinitiators are, for example, those which
  • Absorb wavelength range from 190 to 600 nm.
  • photoinitiators for radical curing systems are benzoin and derivatives, acetophenone and derivatives, such as e.g. 2,2-diacetoxyacetophenone, benzophenone and derivatives, thioxanthone and derivatives, anthraquinone, 1-
  • Benzoylcyclohexanol, organophosphorus compounds e.g. Acylphosphine oxides.
  • the photoinitiators are used, for example, in amounts of 0.1-7% by weight, preferably 0.5-5% by weight, based on the sum of free-radically polymerizable prepolymers, reactive diluents and photoinitiators.
  • the photoinitiators can be used individually or in combination.
  • Photoinitiators for cationic curing systems are substances known as onium salts, which release Lewis acids photolytically under the action of radiation. Examples include diazonium salts, sulfonium salts or iodonium salts. Triarylsulfonium salts are preferred.
  • the photoinitiators for cationically curing systems can be used individually or as mixtures in amounts of 0.5 to 5% by weight, based on the sum of cationically polymerizable prepolymers, reactive diluents and initiators.
  • free-radically curing systems various cationically curing systems or free-radically and cationically curing systems can be combined with one another to produce the basecoats which are curable by means of high-energy radiation. Radically curing systems are preferably used.
  • Preferred free-radically curing binders are those based on polyurethane (meth) acrylates, polyester (meth) acrylates and (meth) acrylic-functional poly (meth) acrylates. Those based on aliphatic polyurethane (meth) acrylates and / or aliphatic (meth) acrylic-functional poly (meth) acrylates are particularly preferred.
  • the basecoats which can be used in the process according to the invention can, in addition to the binders curable by means of high-energy radiation, also contain binders which harden or dry by other mechanisms. The amount of such additional
  • the binder is, for example, up to 50% by weight, based on the UV-curing binder.
  • physically drying binders or chemically crosslinkable binders can also be included.
  • the physically drying binders are, for example, polyurethane, polyurethane urea, polyester, polyester urethane and / or polyacrylate resins which are known to the person skilled in the art and which can optionally be present in combination with melamine resins or cellulose esters. Modifications of the resins mentioned may also be involved, for example acrylated or silicon-modified polyurethane resins and / or polyester resins or so-called lap polymers, ie acrylate copolymers prepared in the presence of, for example, polyesters or polyurethanes.
  • Two-component binder systems based on a hydroxy-functional and an isocyanate-functional component can be used as chemically crosslinkable binders hydroxy-functional and an anhydride component or a polyamine and an acryloyl-functional component can be used.
  • the additional binders that can be used can be aqueous or solvent-based.
  • the binder systems mentioned by way of example are known to the person skilled in the art and are described in detail in the literature. If, in addition to the radiation-curing binders, other binders are used in the basecoats, those based on a hydroxy-functional and an isocyanate-functional component can preferably be used.
  • the basecoat coating compositions which can be used in the process according to the invention contain coloring and / or effect pigments.
  • All paint-typical pigments of organic or inorganic nature are suitable as color pigments.
  • inorganic or organic color pigments are titanium dioxide, micronized titanium dioxide, iron oxide pigments, carbon black, azo pigments, phthalocyanine pigments, quinacridone and pyrrolopyrrole pigments.
  • effect pigments are particularly characterized by a platelet-like structure.
  • effect pigments are: metal pigments, e.g. made of aluminum, copper or other metals; Interference pigments, e.g. metal oxide coated metal pigments, e.g. Titanium dioxide coated or mixed oxide coated
  • the basecoat coating compositions which can be used in the process according to the invention can contain fillers and / or customary paint additives.
  • the additives are the usual additives that can be used in the paint sector.
  • Examples of such additives are leveling agents, for example based on (meth) acrylic homopolymers or silicone oils, rheology-influencing agents such as highly disperse silica or polymeric urea compounds, thickeners such as cross-linked polycarboxylic acid or polyurethane, anti-foaming agents, wetting and elasticizing agents and light stabilizers.
  • fillers are silicon dioxide, barium sulfate and talc. The additives and fillers are used in customary amounts known to the person skilled in the art.
  • the basecoats which can be used in the process according to the invention can be formulated without solvents. Their solids content is then 100% by weight. However, the basecoats can also contain small amounts of organic solvents and / or water. The solvents are common paint solvents.
  • solvents are monohydric or polyhydric alcohols, e.g. Propanol, butanol, hexanol; Glycol ethers or esters, e.g. Diethylene glycol dialkyl ether, dipropylene glycol dialkyl ether, each with Cl to C6 alkyl, ethoxypropanol, butyl glycol; Glycols, e.g. Ethylene glycol, propylene glycol and their oligomers, esters such as e.g. Butyl acetate, amyl acetate, alkyl pyrrolidones, e.g.
  • monohydric or polyhydric alcohols e.g. Propanol, butanol, hexanol
  • Glycol ethers or esters e.g. Diethylene glycol dialkyl ether, dipropylene glycol dialkyl ether, each with Cl to C6 alkyl, ethoxypropanol,
  • N-methylpyrrolidone and ketones e.g. Methyl ethyl ketone, acetone, cyclohexanone; aromatic or aliphatic hydrocarbons, e.g. Toluene, xylene or linear or branched aliphatic C6-C12 hydrocarbons.
  • the color and / or effect basecoat layer is applied in the method according to the invention to optionally precoated substrates.
  • Preferred substrates are metal or plastic substrates.
  • the basecoats are preferably applied to customary primer, filler or other intermediate layers, such as are used for multi-coat painting in the motor vehicle sector. In particular, they are based on a
  • Vehicle refinishing applied to pre-coated vehicle bodies or their parts.
  • the application takes place according to known methods, preferably by spray application.
  • the basecoat can, for example, be applied to customary solvent- or water-based filler, primer or other intermediate layers.
  • the Filler, primer or intermediate layers can already be cured or pre-dried or intermediate dried. That is, the basecoat can be applied, for example, to an old paint job, a cured refinish paint job, a pre-dried or wet-on-wet process using IR radiation, if necessary after a short airing, on a refinish job job of the type mentioned above.
  • the coating agents used to produce the filler, primer or intermediate layers can be based on the physically drying or chemically crosslinking fuel systems that are customary and suitable for vehicle painting.
  • physically drying binders are solvent-based or water-based polyurethane, polyurethane urea, polyester, polyester urethanes or polyacrylate resins, as well as their modifications.
  • solvent-based or water-based chemically crosslinking binders are systems based on oxidatively drying resins, peroxide-curing unsaturated polyesters and acid-curing polyvinyl butyrals and on the basis of binders containing hydroxyl groups, which are crosslinkable with isocyanate-, amino-functional or anhydride-functional components, based on epoxy / polyamine or acryloyl / Polyamine systems.
  • UV radiation sources are preferably those with emissions in the wavelength range from 180 to 420 nm, in particular from 200 to 400 nm.
  • UV radiation sources are optionally doped high-pressure mercury, medium-pressure and low-pressure lamps, gas discharge tubes, such as e.g. Xenon low-pressure lamps, pulsed and non-pulsed UV lasers, UV spotlights, such as UV emitting diodes and black light tubes. Irradiation is preferably carried out with pulsed UV radiation.
  • So-called high-energy electron flash devices (in short: UV flash lamps) are then particularly preferably used as the radiation source.
  • Preferred UV flash lamps emit light from one
  • UV flash lamps preferably contain a plurality of flash tubes, for example quartz tubes filled with inert gas such as xenon.
  • the UV flash lamps should have an illuminance of at least 10 megalux, preferably 10 - 80 megalux per flash discharge on the surface of the coating to be cured.
  • the electrical power per flash discharge should preferably be 1 - 10 kJoules.
  • UV flash lamps are preferably portable devices that can be positioned directly in front of a damaged area to be repaired. UV flash lamps that can be used are described, for example, in WO-A-9411123 and in EP-A-525 340. UV flash lamps are commercially available. Depending on the application conditions and requirements, one or more UV
  • the basecoat layers can be cured by a plurality of successive lightning discharges. 1 to 40 successive lightning discharges are preferably triggered. The distance between the UV flash lamp and the one to be irradiated
  • the substrate surface can be 5-50 cm, preferably 10-25 cm, particularly preferably 15-20 cm.
  • the shielding of the UV lamps to prevent radiation leakage can be e.g. by using an appropriately lined protective housing around the transportable lamp unit or with the help of other safety measures known to the person skilled in the art.
  • the total irradiation time is in the range of a few seconds, for example in the range from 3 milliseconds to 400 seconds, preferably from 4 to 160 seconds, depending on the number of flash discharges selected.
  • the flashes can be triggered, for example, every 4 seconds.
  • the UV flash lamps are ready for use at any time, i.e. they do not require a baking time and can remain switched off between two curing or irradiation processes that are somewhat separated in time, without the loss of time resulting from a baking phase during the renewed irradiation process.
  • the temperatures generated by means of UV radiation (UV flash lamps) on the coating are generally sufficient to cure the additional binders present.
  • a separate hardening step is not necessary.
  • a clear lacquer coating is applied to the basecoat film either after it has completely hardened or wet-on-wet, if appropriate after briefly flashing off.
  • Suitable clearcoats are all solvent-based or water-based clearcoats which are customary in vehicle painting, in particular repair painting, and are known to the person skilled in the art.
  • solvent-based or aqueous clear lacquers based on binders containing hydroxyl groups and / or amino groups and polyisocyanate crosslinkers and on binders based on amino groups and acryloyl-functional binders.
  • the clearcoat layer can be cured at room temperature or forced at, for example, 40-80 ° C. Solvent-based or aqueous are preferred in the process according to the invention
  • a further preferred embodiment of the process according to the invention consists in using as clearcoat one which contains binders curable by means of high-energy radiation. For those curable by means of high-energy radiation
  • Binders are, for example, the radiation-curable binders already described above, which can be used in the basecoat. Binders based on aliphatic polyurethane (meth) acrylates and / or (meth) acrylic-functional poly (meth) acrylates are particularly preferably used in the basecoat and in the clearcoat by means of high-energy radiation.
  • the clear lacquer can be applied wet-on-wet, if necessary after briefly flashing off, to the uncured base lacquer. Then the irradiation with UV rays takes place, with basecoat and clearcoat be hardened together in one work step.
  • UV radiation-curable clearcoats are used in the process according to the invention, special coated transparent fillers can advantageously be present in addition to the additives customary for a clearcoat to increase the scratch resistance.
  • Fillers that can be used here are, for example, micronized aluminum oxide or micronized silicon oxide. These transparent fillers are coated with compounds that contain UV-curable groups, for example with acrylic-functional silanes, and are therefore included in the radiation curing of the clear lacquer.
  • the fillers are available as commercial products, for example under the name AKTISIL * .
  • the process according to the invention gives multilayer coatings with great hardness, high scratch resistance and high gloss.
  • the individual layers of paint show very good interlayer adhesion and resistance to dissolving of the paint layers below or above. The latter properties are particularly pronounced if, in addition to the basecoat, the clearcoat layer also contains binders curable by means of high-energy radiation in the multilayer structure and the same radiation-curable binders and / or reactive thinners are used for both paint layers.
  • the coatings obtained with the method according to the invention otherwise meet the requirements for a refinish paint system in the field of vehicle painting.
  • the drying or hardening of the coatings, in particular the basecoat / clearcoat structure takes place in a greatly reduced time compared to repair lacquer structures which have been dried or hardened in the customary manner.
  • Multi-layer construction must or should be dispensed with, for example in the painting of vehicle interior areas, such as the engine compartment, trunk, door rebates, or in the Painting textured plastic surfaces, the clear coat can be easily omitted.
  • the basecoat hardened by means of high-energy radiation fulfills the function of the clearcoat easily and without any modification, for example with regard to hardness and scratch resistance.
  • the method according to the invention can advantageously be used in the
  • Vehicle refinishing especially of vehicle parts, smaller damaged areas and for spot repair.
  • HALS type 1 part of a commercially available light stabilizer (HALS type) 1 part of a commercially available UV absorber (benzotriazole type) Creation of a multilayer structure
  • the basecoat produced as described above was applied to KTL-primed and coated with customary solvent-based two-component polyurethane fillers in a resulting dry film layer thickness of approx. 60 ⁇ m.
  • Flash-off at room temperature exposes the basecoat to radiation from a UV flash lamp (3500 Ws). It is irradiated with 20 flashes (approx. 80 s).
  • the clear lacquer produced as described above is applied in a resulting dry film layer thickness of approximately 60 ⁇ m.
  • the clear lacquer layer is exposed to the radiation by a UV flash lamp (3500 Ws). It is irradiated with 20 flashes (approx. 80 s).
  • the cured basecoat is overcoated with a solvent-based, conventional 2-component polyurethane clearcoat and cured in the customary manner.

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)

Abstract

The invention relates to a method for multi-layered coating of substrates, whereby a colour and/or effect giving base enamel coating agent is applied to a substrate which has been optionally pre-coated with a ground coating agent and/or filler coating agent and/or other coating agents, whereupon a varnish coating is subsequently applied to the colour and/or effect giving base enamel coating. According to the inventive method, the colour and/or effect giving base enamel coating agent contains bonding agents which harden by means of radical and/or cationic polymerisation under the effect of high-power radiation.

Description

Verfahren zur mehrschichtigen Lackierung von Substraten Die Erfindung betrifft ein Verfahren zur mehrschichtigen Lackierung von Substraten mit einer färb- und/oder effektgebenden Basislack- und einer Klarlackschicht, welches insbesondere Anwendung findet auf dem Gebiet der Fahrzeug- und Fahrzeugteilelackierung und insbesondere zur Reparaturlackierung.The invention relates to a method for multi-layer painting of substrates with a coloring and / or effect basecoat and a clear coat, which is used in particular in the field of vehicle and vehicle parts painting and in particular for refinishing.
Mehrschichtige Fahrzeugreparaturlackierungen bestehen im allgemeinen aus einerMulti-layer vehicle refinishes generally consist of one
Basislack/Klarlack- Deckschichtlackierung, die auf gegebenenfalls mit Grundierungen, Füllern oder weiteren Beschichtungsmitteln vorbeschichtete Substrate aufgebracht wird.Basecoat / clearcoat topcoat which is applied to substrates which may have been precoated with primers, fillers or other coating agents.
Aus ökologischen Gründen ist man bestrebt, auch in der Fahrzeugreparaturlackierung die Lösemittelemission der Beschichtungsmittel zu reduzieren. Insbesondere eine Reduzierung des Lösemittelanteiles in Basislacken, speziell in Effektbasislacken, die mit etwa 80 Gew.-% einen hohen Anteil organischer Lösemittel aufweisen, bringt einen effektiven Beitrag zur Senkung der Lösemittelemission der Gesamtlackierung. Es sind bereits Wasserbasislacke für den Einsatz in der Fahrzeugreparaturlackierung entwickelt worden. Die mit diesen Wasserbasislacken erhaltenen Beschichtungen entsprechen jedoch noch nicht in allen Punkten dem Eigenschaftsniveau konventioneller Basislacke. Beispielsweise sind Wasserfestigkeit, Härte und Zwischenschichthaftung noch unzureichend ausgebildet. Außerdem muß beim Einsatz von Wasserbasislacken eine verlängerte Trockenzeit in Kauf genommen werden, was die Effektivität beispielsweise in einer Lackierwerkstatt beeinträchtigt.For ecological reasons, efforts are also being made to reduce the solvent emissions of the coating agents in vehicle refinishing. In particular, a reduction in the proportion of solvent in basecoats, especially in effect basecoats, which have a high proportion of organic solvents at about 80% by weight, makes an effective contribution to reducing the solvent emission of the overall coating. Water-based paints have already been developed for use in vehicle refinishing. However, the coatings obtained with these waterborne basecoats do not yet correspond in all points to the property level of conventional basecoats. For example, water resistance, hardness and interlayer adhesion are still insufficiently developed. In addition, an extended drying time must be accepted when using waterborne basecoats, which impairs the effectiveness, for example, in a paint shop.
Es ist bereits bekannt, in der Fahrzeuglackierung mittels energiereicher Strahlung härtbare Beschichtungsmittel einzusetzen.It is already known to use coating agents which can be hardened in vehicle painting by means of high-energy radiation.
In der EP-A-000 407 werden strahlenhärtbare Überzugsmittel beschrieben auf Basis eines mit Acrylsäure veresterten OH-funktionellen Polyesterharzes, einer Vinylverbindung, eines Photoinitiators und eines Polyisocyanates. In einem 1. Härtungsschritt erfolgt die Strahlenhärtung mittels UV-Licht und in einem 2. Härtungsschritt erhält der Überzug durch die OH/NCO- Vernetzung seine Endhärte. Der 2. Härtungsschritt kann bei 130 - 200 °C oder über mehrere Tage bei Raumtemperatur erfolgen.EP-A-000 407 describes radiation-curable coating compositions based on an OH-functional polyester resin esterified with acrylic acid, one Vinyl compound, a photoinitiator and a polyisocyanate. In a 1st hardening step the radiation is hardened by means of UV light and in a 2nd hardening step the coating gets its final hardness through the OH / NCO crosslinking. The second curing step can take place at 130 - 200 ° C or over several days at room temperature.
Die EP-A-540 884 beschreibt ein Verfahren zur Herstellung einer Mehrschichtlackierung für die Kraftfahrzeugserienlackierung durch Auftrag einer Klarlackschicht auf eine getrocknete bzw. gehärtete Basislackschicht, wobei das Klarlackbeschichtungsmittel durch radikalische und/oder kationische Polymerisation härtbare Bindemittel enthält, und die Härtung mittels energiereicher Strahlung durchgeführt wird. Nach Bestrahlung der Klaraickschicht erfolgt der Einbrennprozeß, wobei Basislack und Klarlack gemeinsam bei z.B. 80 - 160 C eingebrannt werden.EP-A-540 884 describes a process for the production of a multi-layer coating for automotive serial painting by applying a clear coat on a dried or hardened basecoat layer, the clearcoat coating agent containing curable binders by free-radical and / or cationic polymerization, and the curing being carried out by means of high-energy radiation becomes. After the clear layer has been irradiated, the stoving process takes place, the basecoat and clearcoat being used together in e.g. 80 - 160 C.
In der EP-A-247 563 werden mittels UV-Strahlung härtbare Klarlacke beschrieben aufEP-A-247 563 describes clearcoats curable by means of UV radiation
Basis einer ρoly(meth)acryloylfunktionellen Verbindung, eines Polyolmono(meth)acrylates, eines Polyisocyanates, eines Lichtstabilisators und eines Photoinitiators. Ein Teil der strahlenhärtbaren Bindemittel enthält hier noch Hydroxyfunktionen, die mit dem vorhandenen Polyisocyanat reagieren können und eine zusätzliche Härtungsmöglichkeit bieten.Basis of a ρoly (meth) acryloyl-functional compound, a polyol mono (meth) acrylate, a polyisocyanate, a light stabilizer and a photoinitiator. Some of the radiation-curable binders here also contain hydroxyl functions which can react with the polyisocyanate present and offer an additional curing option.
Die US-A-4 668 529 beschreibt ein mittels UV-Strahlung härtbares 1K- Füllerbeschichtungsmittel für die Reparaturlackierung. Das Bindemittel basiert auf Tripropylenglykoltriacrylat und Trimethylpropantriacrylat. Zusätzlich ist ein Epoxidharz auf Basis eines Bisphenol A-Diglycidy lethers enthalten.US-A-4 668 529 describes a UV-curable 1K filler coating agent for refinishing. The binder is based on tripropylene glycol triacrylate and trimethylpropane triacrylate. In addition, an epoxy resin based on a bisphenol A diglycidyl ether is included.
Aufgabe der Erfindung war es, ein Verfahren zur Herstellung einer mehrschichtigen Lackierung, insbesondere Reparaturlackierung bereitzustellen, welches im Gesamtaufbau eine erhebliche Reduzierung der Lösemittelemission ermöglicht und kurze Trockenzeiten aufweist. Außerdem sollen sehr gute Wasserfestigkeit und Härte sowie sehr gute Zwischenschichthaftung und Anlöseresistenz des Basislackes gegenüber darunter und darüber liegenden Lackschichten gewährleistet sein. Die Aufgabe wird gelöst durch ein Verfahren zur Herstellung einer mehrschichtigen Lackierung, bei dem auf ein gegebenenfalls mit einem Grundierungs- und/oder Füllerbeschichtungsmittel und/oder weiteren Beschichtungsmitteln vorbeschichtetes Substrat ein färb- und/oder effektgebendes Basislackbeschichtungsmittel aufgebracht wird und anschließend auf die färb- und/oder effektgebende Basislackschicht eine Klarlackschicht appliziert wird, dadurch gekennzeichnet, daß als färb- und/oder effektgebendes Basislackbeschichtungsmittel ein solches verwendet wird, das unter Einwirkung energiereicher Strahlung durch radikalische und/oder kationische Polymerisation härtbare Bindemittel enthält.The object of the invention was to provide a method for producing a multilayer coating, in particular refinishing coating, which enables a significant reduction in the solvent emission in the overall structure and has short drying times. In addition, very good water resistance and hardness as well as very good interlayer adhesion and resistance to dissolving of the basecoat with respect to the lacquer layers below and above should be guaranteed. The object is achieved by a process for producing a multilayer coating, in which a coloring and / or effect-imparting basecoat coating agent is applied to a substrate which may have been pre-coated with a primer and / or filler coating agent and / or further coating agents, and then onto the coloring and / or effect-imparting basecoat layer, a clearcoat layer is applied, characterized in that the coloring and / or effect-imparting basecoat coating agent used is one which contains, under the action of high-energy radiation, binders curable by free-radical and / or cationic polymerization.
Es war überraschend und aus dem Stand der Technik nicht herleitbar, daß die mit dem erfindungsgemäßen Verfahren erhaltenen Mehrschichtlackierungen bezüglich solcher Eigenschaften wie Härte, Kratzfestigkeit, Wasser- und Chemikalienbeständigkeit, das gleiche hohe für eine Lackierung, insbesondere eine Reparaturlackierung erforderliche, Eigenschaftsniveau zeigen, wie Mehrschichtlackierungen, die mit für die Fahrzeug(reparatur)lackierung üblichen Basislack/Klarlackschichten erstellt wurden. Ebenso überrachend war, daß verschiedene Eigenschaften, wie z.B. Zwischenschichthaftung, Anlöseresistenz gegenüber darunter- oder darüberliegenden Lackschichten, Kraftstoff-, Baumharz- und Pankreatinbeständigkeit, noch erheblich verbessert werden konnten.It was surprising and cannot be deduced from the prior art that the multi-layer coatings obtained with the process according to the invention show the same high level of properties required for a coating, in particular a refinishing coating, with respect to properties such as hardness, scratch resistance, water and chemical resistance as multi-layer coatings which were created with the basecoat / clearcoat layers customary for vehicle (repair) painting. It was also surprising that various properties, e.g. Interlayer adhesion, resistance to dissolving against layers of paint above or below, resistance to fuel, tree resin and pancreatin, could still be significantly improved.
Bei den im erfindungsgemäßen Verfahren einsetzbaren färb- und/oder effektgebenden Basislacken handelt es sich Beschichtungsmittel, die mittels energiereicher Strahlung über eine radikalische und/ oder kationische Polymerisation vernetzen. Es kann sich dabei um festkörperreiche wäßrige Systeme handeln, beispielsweise mit einem Festkörpergehalt von 50 bis 95 Gew.-%, die als Emulsion vorliegen, die Systeme können jedoch auch in lösemittelhaltiger Form vorliegen. Es kann sich jedoch auch um 100 %ige Beschichtungsmittel handeln, die ohne Lösungsmittel und ohne Wasser appliziert werden können.The color and / or effect basecoats which can be used in the process according to the invention are coating compositions which crosslink by means of high-energy radiation via free-radical and / or cationic polymerization. These can be aqueous systems with a high solids content, for example with a solids content of 50 to 95% by weight, which are present as an emulsion, but the systems can also be in a solvent-containing form. However, it can also be a 100% coating agent that can be applied without solvent and without water.
Als mittels energiereicher Strahlung härtbare Bindemittel können in den im erfindungsgemäßen Verfahren einsetzbaren Basislacken alle üblichen strahlenhärtbaren Bindemittel oder deren Mischungen eingesetzt werden, die dem Fachmann bekannt und in der Literatur beschrieben sind. Es handelt sich entweder um durch radikalische oder durch kationische Polymerisation vernetzbare Bindemittel. Bei ersteren entstehen durch Einwirkung von energiereicher Strahlung auf die Photoinitiatoren Radikale, die dann die Vernetzungsreaktion auslösen. Bei den kationisch härtenden Systemen werden durch die Bestrahlung aus Initiatoren Lewis-Säuren gebildet, die dann ihrerseits die Vernetzungsreaktion auslösen.As a hardenable by means of high-energy radiation binders in the Basecoats which can be used according to the invention can be all of the customary radiation-curable binders or mixtures thereof which are known to the person skilled in the art and are described in the literature. They are either binders which can be crosslinked by free-radical polymerization or by cationic polymerization. In the former, radicals are generated by the action of high-energy radiation on the photoinitiators, which then trigger the crosslinking reaction. In the case of the cationically curing systems, Lewis acids are formed by the irradiation from initiators, which in turn trigger the crosslinking reaction.
Bei den radikalisch härtenden Bindemitteln kann es sich z.B. um Prepolymere oderThe free-radically curing binders can e.g. to prepolymers or
Oligomere, die radikalisch polymerisierbare olefinische Doppelbindungen im Molekül aufweisen, handeln. Beispiele für Prepolymere oder Oligomere sind (meth)acrylfunktionelle (Meth)acrylcopolymere, Epoxidharz(meth)acrylate, Polyester(meth)acrylate, Polyether(meth)acrylate, Polyurethan(meth)acrylate, , Amino(meth)acrylate, Silikon(meth)acrylate, Melamin(meth)acrylate, ungesättigteAct oligomers which have free-radically polymerizable olefinic double bonds in the molecule. Examples of prepolymers or oligomers are (meth) acrylic-functional (meth) acrylic copolymers, epoxy resin (meth) acrylates, polyester (meth) acrylates, polyether (meth) acrylates, polyurethane (meth) acrylates,, amino (meth) acrylates, silicone (meth) acrylates, melamine (meth) acrylates, unsaturated
Polyurethane oder ungesättigte Polyester. Die zahlenmittlere Molmasse (Mn) dieser Verbindungen liegt bevorzugt bei 200 bis 10000. Die Bindemittel können einzeln oder im Gemisch eingesetzt werden.Polyurethane or unsaturated polyester. The number average molecular weight (Mn) of these compounds is preferably from 200 to 10,000. The binders can be used individually or in a mixture.
Die Prepolymere können in Kombination mit Reaktiv Verdünnern, d.h. reaktiven polymerisierbaren flüssigen Monomeren, vorliegen. Die Reaktivverdünner werden im allgemeinen in Mengen von 1 - 50 Gew.-%, bevorzugt 5 - 30 Gew.-%, bezogen auf das Gesamtgewicht von Prepolymer und Reaktivverdünner, eingesetzt. Die Reaktivverdünner können mono-, di- oder polyungesättigt sein. Beispiele für monoungesättigte Reaktivverdünner sind: (Meth)acrylsäure und deren Ester,The prepolymers can be used in combination with reactive diluents, i.e. reactive polymerizable liquid monomers. The reactive diluents are generally used in amounts of 1-50% by weight, preferably 5-30% by weight, based on the total weight of prepolymer and reactive diluent. The reactive diluents can be mono-, di- or polyunsaturated. Examples of monounsaturated reactive diluents are: (meth) acrylic acid and its esters,
Maleinsäure und deren Halbester, Vinylacetat, Vinylether, substituierte Vinylharnstoffe, Styrol, Vinyltoluol. Beispiele für diungesättigte Reaktivverdünner sind: Di(meth)acrylate wie Alkylenglykol-di(meth)acrylat, Polyethylenglykol- di(meth)acrylat, l,3-Butandiol-di(meth)acrylat, Vinyl(meth)acrylat, Allyl(meth)acrylat, Divinylbenzol, Dipropylenglykol-di(meth)acrylat, Hexandiol-di(meth)acrylat. Beispiel für polyungesättigte Reaktivverdünner sind: Glycerin-tri(meth)acrylat, Trimethylolpropan-tri(meth)acrylat, Pentaerythrit-tri(meth)acrylat, Pentaerythrit- tetra(meth)acrylat. Die Reaktivverdünner können einzeln oder im Gemisch eingesetzt werden. Bevorzugt werden als Reaktivverdünner Diacrylate wie z.B. Dipropylenglykoldiacrylat, Tripropylenglykoldiacrylat und/oder Hexandioldiacrylat eingesetzt.Maleic acid and its half esters, vinyl acetate, vinyl ether, substituted vinyl ureas, styrene, vinyl toluene. Examples of unsaturated reactive diluents are: di (meth) acrylates such as alkylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,3-butanediol di (meth) acrylate, vinyl (meth) acrylate, allyl (meth) acrylate, divinylbenzene, dipropylene glycol di (meth) acrylate, hexanediol di (meth) acrylate. Examples of polyunsaturated reactive diluents are: glycerol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate. The reactive diluents can be used individually or in a mixture. Diacrylates such as dipropylene glycol diacrylate, tripropylene glycol diacrylate and / or hexanediol diacrylate are preferably used as reactive diluents.
Als Bindemittel für kationisch polymerisierbare Systeme können die üblichen dem Fachmann bekannten und in der Literatur beschriebenen Bindemittel eingesetzt werden. Es kann sich dabei beispielsweise um polyfunktionelle Epoxyoligomere, die mehr als zwei Epoxygruppen im Molekül enthalten, handeln. Es handelt sich beispielsweise um Polyalkylenglykoldiglycidy lether, hydrierte Bisphenol-A-The usual binders known to the person skilled in the art and described in the literature can be used as binders for cationically polymerizable systems. These can be, for example, polyfunctional epoxy oligomers which contain more than two epoxy groups in the molecule. For example, polyalkylene glycol diglycidyl ether, hydrogenated bisphenol A
Glycidylether, Epoxyurethanharze, Glycerintriglycidylether,Glycidyl ether, epoxy urethane resins, glycerol triglycidyl ether,
Diglycidylhexahydrophthalat, Diglycidylester von Dimersäuren, epoxidierte Derivate des (Methyl)cyclohexens, wie z.B. 3,4-Epoxycyclohexyl-methyl(3,4- epoxycyclohexan)carboxylat oder epoxidiertes Polybutadien. Das Zahlenmittel der Molmasse (Mn) der Polyepoxidverbindungen liegt bevorzugt unter 10000. Es können auch Reaktivverdünner, wie z.B. Cyclohexenoxid, Butenoxid, Butandioldiglycidy lether oder Hexandioldiglycidy lether, eingesetzt werden.Diglycidyl hexahydrophthalate, diglycidyl ester of dimer acids, epoxidized derivatives of (methyl) cyclohexene, e.g. 3,4-epoxycyclohexylmethyl (3,4-epoxycyclohexane) carboxylate or epoxidized polybutadiene. The number average molecular weight (Mn) of the polyepoxide compounds is preferably less than 10,000. Reactive diluents, such as e.g. Cyclohexene oxide, butene oxide, butanediol diglycidyl ether or hexanediol diglycidyl ether can be used.
Die unter Strahleneinwirkung härtenden Bindemittelsysteme enthalten Photoinitiatoren. Geeignete Photoinitiatoren sind beispielsweise solche, die imThe binder systems curing under the action of radiation contain photoinitiators. Suitable photoinitiators are, for example, those which
Wellenlängenbereich von 190 bis 600 nm absorbieren.Absorb wavelength range from 190 to 600 nm.
Beispiele für Photoinitiatoren für radikalisch härtende Systeme sind Benzoin und - derivate, Acetophenon, und -derivate, wie z.B. 2,2-Diacetoxyacetophenon, Benzophenon und -derivate, Thioxanthon und -derivate, Anthrachinon, 1-Examples of photoinitiators for radical curing systems are benzoin and derivatives, acetophenone and derivatives, such as e.g. 2,2-diacetoxyacetophenone, benzophenone and derivatives, thioxanthone and derivatives, anthraquinone, 1-
Benzoylcyclohexanol, phosphororganische Verbindungen, wie z.B. Acylphosphinoxide. Die Photoinitiatoren werden beispielsweise in Mengen von 0,1-7 Gew.-%, bevorzugt 0,5 - 5 Gew.-% eingesetzt, bezogen auf die Summe von radikalisch polymerisierbaren Prepolymeren, Reaktivverdünnern und Photoinitiatoren. Die Photoinitiatoren können einzeln oder in Kombination eingesetzt werden.Benzoylcyclohexanol, organophosphorus compounds, e.g. Acylphosphine oxides. The photoinitiators are used, for example, in amounts of 0.1-7% by weight, preferably 0.5-5% by weight, based on the sum of free-radically polymerizable prepolymers, reactive diluents and photoinitiators. The photoinitiators can be used individually or in combination.
Außerdem können weitere synergistische Komponenten, z.B. tertiäre Amine, eingesetzt werden. Photoinitiatoren für kationisch härtende Systeme sind Substanzen, die als Oniumsalze bekannt sind, welche unter Strahleneinwirkung photolytisch Lewis-Säuren freisetzen. Beispiele hierfür sind Diazoniumsalze, Sulfoniumsalze oder Jodoniumsalze. Bevorzugt sind Triarylsulfoniumsalze. Die Photoinitiatoren für kationisch härtende Systeme können in Mengen von 0,5 bis 5 Gew.-%, bezogen auf die Summe von kationisch polymerisierbaren Prepolymeren, Reaktivverdünnern und Initiatoren, einzeln oder als Gemische eingesetzt werden.In addition, other synergistic components, for example tertiary amines, can be used. Photoinitiators for cationic curing systems are substances known as onium salts, which release Lewis acids photolytically under the action of radiation. Examples include diazonium salts, sulfonium salts or iodonium salts. Triarylsulfonium salts are preferred. The photoinitiators for cationically curing systems can be used individually or as mixtures in amounts of 0.5 to 5% by weight, based on the sum of cationically polymerizable prepolymers, reactive diluents and initiators.
Zur Herstellung der mittels energiereicher Strahlung härtbaren Basislacke können verschiedene radikalisch härtende Systeme, verschiedene kationisch härtende Systeme oder radikalisch und kationisch härtende Systeme miteinander kombiniert werden. Bevorzugt werden radikalisch härtende Systeme eingesetzt. Bevorzugte radikalisch härtende Bindemittel sind solche auf Basis von Polyurethan(meth)acrylaten, Polyester(meth)acrylaten und (meth)acrylfunktionellen Poly(meth)acrylaten. Besonders bevorzugt werden solche auf Basis von aliphatischen Polyurethan(meth)acrylaten und/oder aliphatischen (meth)acrylfunktionellen Poly(meth)acrylaten.Various free-radically curing systems, various cationically curing systems or free-radically and cationically curing systems can be combined with one another to produce the basecoats which are curable by means of high-energy radiation. Radically curing systems are preferably used. Preferred free-radically curing binders are those based on polyurethane (meth) acrylates, polyester (meth) acrylates and (meth) acrylic-functional poly (meth) acrylates. Those based on aliphatic polyurethane (meth) acrylates and / or aliphatic (meth) acrylic-functional poly (meth) acrylates are particularly preferred.
Die im erfindungsgemäßen Verfahren einsetzbaren Basislacke können neben den mittels energiereicher Strahlung härtbaren Bindemitteln noch Bindemittel enthalten, die nach anderen Mechanismen härten bzw. trocknen. Die Menge solcher zusätzlicherThe basecoats which can be used in the process according to the invention can, in addition to the binders curable by means of high-energy radiation, also contain binders which harden or dry by other mechanisms. The amount of such additional
Bindemittel liegt beispielsweise bei bis zu 50 Gew.-%, bezogen auf das UV-härtende Bindemittel. So können z.B. zusätzlich physikalisch trocknende Bindemittel oder chemisch vernetzbare Bindemittel enthalten sein. Bei den physikalisch trocknenden Bindemitteln handelt es sich beispielsweise um dem Fachmann geläufige Polyurethan-, Polyurethanharnstoff-, Polyester-, Polyesterurethan- und/oder Polyacrylatharze, die gegebenenfalls in Kombination mit Melaminharzen oder Celluloseestern vorliegen können. Es kann sich auch um Modifizierungen der genannten Harze handeln, z.B. um acrylierte oder siliziummodifizierte Polyurethanharze und/oder Polyesterharze oder um sogenante Schoßpolymerisate, d.h. um in Gegenwart von z.B. Polyestern oder Polyurethanen hergestellte Acrylatcopolymere. Als chemisch vernetzbare Bindemittel können beispielsweise zweikomponentige Bindemittelsysteme auf Basis einer hydroxy funktioneilen und einer isocyanatfunktionellen Komponente, einer hydroxyfunktionellen und einer Anhydridkomponente oder einer Polyamin- und einer acryloylfunktionellen Komponente eingesetzt werden. Bei den zusätzlich einsetzbaren Bindemitteln kann es sich um solche auf wäßriger oder Lösemittelbasis handeln. Die beispielhaft genannten Bindemittelsysteme sind dem Fachmann bekannt und in der Literatur ausführlich beschrieben. Werden in den Basislacken neben den strahlenhärtenden Bindemitteln noch weitere Bindemittel eingesetzt, dann können solche auf Basis einer hydroxyfunktionellen und einer isocyanatfunktionellen Komponente bevorzugt eingesetzt werden.The binder is, for example, up to 50% by weight, based on the UV-curing binder. For example, physically drying binders or chemically crosslinkable binders can also be included. The physically drying binders are, for example, polyurethane, polyurethane urea, polyester, polyester urethane and / or polyacrylate resins which are known to the person skilled in the art and which can optionally be present in combination with melamine resins or cellulose esters. Modifications of the resins mentioned may also be involved, for example acrylated or silicon-modified polyurethane resins and / or polyester resins or so-called lap polymers, ie acrylate copolymers prepared in the presence of, for example, polyesters or polyurethanes. Two-component binder systems based on a hydroxy-functional and an isocyanate-functional component, for example, can be used as chemically crosslinkable binders hydroxy-functional and an anhydride component or a polyamine and an acryloyl-functional component can be used. The additional binders that can be used can be aqueous or solvent-based. The binder systems mentioned by way of example are known to the person skilled in the art and are described in detail in the literature. If, in addition to the radiation-curing binders, other binders are used in the basecoats, those based on a hydroxy-functional and an isocyanate-functional component can preferably be used.
Die im erfindungsgemäßen Verfahren einsetzbaren Basislackbeschichtungsmittel enthalten färb- und/oder effektgebende Pigmente. Als farbgebende Pigmente sind alle lacküblichen Pigmente organischer oder anorganischer Natur geeignet. Beispiele für anorganische oder organische Farbpigmente sind Titandioxid, mikronisiertes Titandioxid, Eisenoxidpigmente, Ruß, Azopigmente, Phthalocyaninpigmente, Chinacridon- und Pyrrolopyrrolpigmente.The basecoat coating compositions which can be used in the process according to the invention contain coloring and / or effect pigments. All paint-typical pigments of organic or inorganic nature are suitable as color pigments. Examples of inorganic or organic color pigments are titanium dioxide, micronized titanium dioxide, iron oxide pigments, carbon black, azo pigments, phthalocyanine pigments, quinacridone and pyrrolopyrrole pigments.
Die Effektpigmente zeichnen sich insbesondere durch einen plättchenartigen Aufbau aus. Beispiele für Effektpigmente sind: Metallpigmente, z.B. aus Aluminium, Kupfer oder anderen Metallen; Interferenzpigmente, wie z.B. metalloxidbeschichtete Metallpigmente, z.B. titandioxidbeschichtetes oder mischoxidbeschichtetesThe effect pigments are particularly characterized by a platelet-like structure. Examples of effect pigments are: metal pigments, e.g. made of aluminum, copper or other metals; Interference pigments, e.g. metal oxide coated metal pigments, e.g. Titanium dioxide coated or mixed oxide coated
Aluminium, beschichteter Glimmer, wie z.B. titandioxidbeschichteter Glimmer und Graphiteffektpigmente. Vorteilhaft können, beispielsweise zur Verbesserung der Härte, UV-härthabe Pigmente und gegebenenfalls auch Füllstoffe eingesetzt werden. Es handelt sich hierbei um mit strahlenhärtbaren Verbindungen, z.B. acrylfunktionellen Silanen, gecoatete Pigmente/Füllstoffe, die somit in denAluminum, coated mica, e.g. titanium dioxide coated mica and graphite effect pigments. Pigments and, if appropriate, also fillers can advantageously be used, for example to improve the hardness. These are with radiation-curable compounds, e.g. acrylic functional silanes, coated pigments / fillers, which are thus in the
Strahlenhärteprozeß mit einbezogen werden.Radiation hardness process to be involved.
Die im erfmdungsgemäßen Verfahren einsetzbaren Basislackbeschichtungsmittel können Füllstoffe und/oder lackübliche Additive enthalten. Bei den Additiven handelt es sich um die üblichen auf dem Lacksektor einsetzbaren Additive. Beispiele für solche Additive sind Verlaufsmittel, z.B. auf der Basis von (Meth)acryl- Homopolymerisaten oder Silikonölen, rheologiebeeinflussende Mittel, wie hochdisperse Kieselsäure oder polymere Harnstoffverbindungen, Verdicker, wie anvernetzte Polycarbonsäure oder Polyurethane, Antischaummittel, Netz- und Elastifizierungsmittel sowie Lichtschutzmittel. Beispiele für Füllstoffe sind Siliciumdioxid, Bariumsulfat und Talkum. Die Additive und Füllstoffe werden in üblichen, dem Fachmann geläufigen Mengen eingesetzt.The basecoat coating compositions which can be used in the process according to the invention can contain fillers and / or customary paint additives. The additives are the usual additives that can be used in the paint sector. Examples of such additives are leveling agents, for example based on (meth) acrylic homopolymers or silicone oils, rheology-influencing agents such as highly disperse silica or polymeric urea compounds, thickeners such as cross-linked polycarboxylic acid or polyurethane, anti-foaming agents, wetting and elasticizing agents and light stabilizers. Examples of fillers are silicon dioxide, barium sulfate and talc. The additives and fillers are used in customary amounts known to the person skilled in the art.
Die im erfindungsgemäßen Verfahren einsetzbaren Basislacke können lösemittelfrei formuliert werden. Ihr Festkörpergehalt beträgt dann 100 Gew.-% . Die Basislacke können jedoch auch geringe Mengen organische Lösemittel und/oder Wasser enthalten. Bei den Lösemitteln handelt es sich um übliche lacktechnische Lösemittel.The basecoats which can be used in the process according to the invention can be formulated without solvents. Their solids content is then 100% by weight. However, the basecoats can also contain small amounts of organic solvents and / or water. The solvents are common paint solvents.
Diese können aus der Herstellung der Bindemittel stammen oder werden separat zugegeben. Beispiele für solche Lösemittel sind ein- oder mehrwertige Alkohole, z.B. Propanol, Butanol, Hexanol; Glykolether oder -ester, z.B. Diethylenglykoldialkylether, Dipropylenglykoldialkylether, jeweils mit Cl- bis C6- Alkyl, Ethoxypropanol, Butylglykol; Glykole, z.B. Ethylenglykol, Propylenglykol und deren Oligomere, Ester, wie z.B. Butylacetat, Amylacetat, Alkylpyrrolidone, z.B. N- Methylpyrrolidon sowie Ketone, z.B. Methylethylketon, Aceton, Cyclohexanon; aromatische oder aliphatische Kohlenwasserstoffe, z.B. Toluol, Xylol oder lineare oder verzweigte aliphatische C6-C12-Kohlenwasserstoffe.These can originate from the production of the binders or are added separately. Examples of such solvents are monohydric or polyhydric alcohols, e.g. Propanol, butanol, hexanol; Glycol ethers or esters, e.g. Diethylene glycol dialkyl ether, dipropylene glycol dialkyl ether, each with Cl to C6 alkyl, ethoxypropanol, butyl glycol; Glycols, e.g. Ethylene glycol, propylene glycol and their oligomers, esters such as e.g. Butyl acetate, amyl acetate, alkyl pyrrolidones, e.g. N-methylpyrrolidone and ketones, e.g. Methyl ethyl ketone, acetone, cyclohexanone; aromatic or aliphatic hydrocarbons, e.g. Toluene, xylene or linear or branched aliphatic C6-C12 hydrocarbons.
Der Auftrag der färb- und/oder effektgebenden Basislackschicht erfolgt im erfindungsgemäßen Verfahren auf gegebenenfalls vorbeschichtete Substrate. Bevorzugte Substrate sind Metall- oder Kunststoff Substrate. Bevorzugt werden die Basislacke auf übliche Grundierungs-, Füller- oder weitere Zwischenschichten, wie sie für die Mehrschichtlackierung auf dem Kraftfahrzeugsektor verwendet werden, appliziert. Insbesondere werden sie auf eine im Rahmen derThe color and / or effect basecoat layer is applied in the method according to the invention to optionally precoated substrates. Preferred substrates are metal or plastic substrates. The basecoats are preferably applied to customary primer, filler or other intermediate layers, such as are used for multi-coat painting in the motor vehicle sector. In particular, they are based on a
Fahrzeugreparaturlackierung bereits vorbeschichtete Fahrzeugkarosse bzw. deren Teile aufgebracht. Die Applikation erfolgt nach bekannten Methoden, bevorzugt mittels Spritzauftrag.Vehicle refinishing applied to pre-coated vehicle bodies or their parts. The application takes place according to known methods, preferably by spray application.
Der Basislack kann beispielsweise auf übliche lösemittel- oder wasserbasierende Füller-, Grundierungs- oder weitere Zwischenschichten aufgebracht werden. Die Füller-, Grundierungs- oder Zwischenschichten können dabei bereits ausgehärtet oder vorgetrocknet bzw. zwischengetrocknet sein. D.h. , der Basislack kann z.B. auf eine Altlackierung, eine ausgehärtete Reparaturlackierung, eine mittels IR-Strahlung vorgetrocknete oder naß-in-naß, gegebenenfalls nach kurzem Ab lüften, auf eine Reparaturlackierung der oben beispielhaft genannten Art aufgebracht werden.The basecoat can, for example, be applied to customary solvent- or water-based filler, primer or other intermediate layers. The Filler, primer or intermediate layers can already be cured or pre-dried or intermediate dried. That is, the basecoat can be applied, for example, to an old paint job, a cured refinish paint job, a pre-dried or wet-on-wet process using IR radiation, if necessary after a short airing, on a refinish job job of the type mentioned above.
Die zur Herstellung der Füller-, Grundierungs- oder Zwischenschichten eingesetzten Beschichtungsmittel können auf den für die Fahrzeuglackierung üblichen und geeigneten physikalisch trocknenden oder chemisch vernetzenden Bmdemittelsystemen basieren. Beispiele für physikalisch trocknende Bindemittel sind lösemittel- oder wasserbasierende Polyurethan-, Polyurethanharnstoff-, Polyester-, Polyesterurethane oder Polyacrylatharze, sowie deren Modifizierungen. Beispiele für lösemittel- oder wasserbasierende chemisch vernetzende Bindemittel sind Systeme auf Basis oxidativ trocknender Harze, peroxidhärtender ungesättigter Polyester und säurehärtender Polyvinylbutyrale sowie auf Basis hydroxylgruppenhaltiger Bindemittel, die mit isocyanat-, aminofunktionellen oder anhydridfunktionellen Komponenten vernetzbar sind, auf Basis von Epoxid/Polyamin- oder Acryloyl/Polyamin-Systemen.The coating agents used to produce the filler, primer or intermediate layers can be based on the physically drying or chemically crosslinking fuel systems that are customary and suitable for vehicle painting. Examples of physically drying binders are solvent-based or water-based polyurethane, polyurethane urea, polyester, polyester urethanes or polyacrylate resins, as well as their modifications. Examples of solvent-based or water-based chemically crosslinking binders are systems based on oxidatively drying resins, peroxide-curing unsaturated polyesters and acid-curing polyvinyl butyrals and on the basis of binders containing hydroxyl groups, which are crosslinkable with isocyanate-, amino-functional or anhydride-functional components, based on epoxy / polyamine or acryloyl / Polyamine systems.
Nach Applikation des im erfmdungsgemäßen Verfahren einsetzbaren Basislackes auf einen der vorstehend genannten Untergründe wird der Basislack, gegebenenfalls nach einer kurzen Ablüftphase, energiereicher Strahlung, bevorzugt UV-Strahlung ausgesetzt. UV-Strahlenquellen sind bevorzugt solche mit Emissionen im Wellenlängenbereich von 180 bis 420 nm, insbesondere von 200 bis 400 nm. Beispiele für derartige UV-Strahlungsquellen sind gegebenenfalls dotierte Quecksilberhochdruck-, Mitteldruck- und Niederdruckstrahler, Gasentladungsröhren, wie z.B. Xenonniederdrucklampen, gepulste und ungepulste UV-Laser, UV- Punktstrahler, wie z.B. UV-emittierende Dioden und Schwarzlichtröhren. Bevorzugt erfolgt die Bestrahlung mit gepulster UV-Strahlung. Als Strahlungsquelle werden dann besonders bevorzugt sogenannte Hochenergieelektronen-Blitzeinrichtungen (kurz : UV-Blitzlampen) eingesetzt. Bevorzugte UV-Blitzlampen emittieren Licht einerAfter application of the basecoat which can be used in the process according to the invention to one of the above-mentioned substrates, the basecoat is exposed to high-energy radiation, preferably UV radiation, if appropriate after a short flash-off phase. UV radiation sources are preferably those with emissions in the wavelength range from 180 to 420 nm, in particular from 200 to 400 nm. Examples of such UV radiation sources are optionally doped high-pressure mercury, medium-pressure and low-pressure lamps, gas discharge tubes, such as e.g. Xenon low-pressure lamps, pulsed and non-pulsed UV lasers, UV spotlights, such as UV emitting diodes and black light tubes. Irradiation is preferably carried out with pulsed UV radiation. So-called high-energy electron flash devices (in short: UV flash lamps) are then particularly preferably used as the radiation source. Preferred UV flash lamps emit light from one
Wellenlänge von 200 bis 900 nm mit einem Maximum bei etwa 300 bis 500 nm. Die UV-Blitzlampen enthalten bevorzugt einen Mehrzahl von Blitzröhren, beispielsweise mit inertem Gas, wie Xenon, gefüllte Quarzröhren. Die UV-Blitzlampen sollen an der Oberfläche des zu härtenden Überzuges eine Beleuchtungsstärke von mindestens 10 Megalux, bevorzugt von 10 - 80 Megalux pro Blitzentladung bewirken. Die elektrische Leistung pro Blitzentladung soll bevorzugt 1 - 10 kJoule betragen. Bei denWavelength from 200 to 900 nm with a maximum at about 300 to 500 nm UV flash lamps preferably contain a plurality of flash tubes, for example quartz tubes filled with inert gas such as xenon. The UV flash lamps should have an illuminance of at least 10 megalux, preferably 10 - 80 megalux per flash discharge on the surface of the coating to be cured. The electrical power per flash discharge should preferably be 1 - 10 kJoules. Both
UV-Blitzlampen handelt es sich bevorzugt um transportable Einrichtungen, die direkt vor einer auszubessernden Schadstelle positioniert werden können. Einsetzbare UV- Blitzlampen sind beispielsweise beschrieben in den WO-A-9411123 und in der EP-A- 525 340. UV-Blitzlampen sind im Handel erhältlich. Es können je nach anwendungstechnischen Gegebenheiten und Notwendigkeiten ein oder mehrere UV-UV flash lamps are preferably portable devices that can be positioned directly in front of a damaged area to be repaired. UV flash lamps that can be used are described, for example, in WO-A-9411123 and in EP-A-525 340. UV flash lamps are commercially available. Depending on the application conditions and requirements, one or more UV
Blitzlampen eingesetzt werden.Flash lamps are used.
Die Härtung der Basislackschichten kann durch eine Mehrzahl aufeinanderfolgender Blitzentladungen erfolgen. Bevorzugt werden 1 bis 40 aufeinanderfolgende Blitzentladungen ausgelöst. Der Abstand der UV-Blitzlampe zur zu bestrahlendenThe basecoat layers can be cured by a plurality of successive lightning discharges. 1 to 40 successive lightning discharges are preferably triggered. The distance between the UV flash lamp and the one to be irradiated
Substratoberfläche kann dabei 5 - 50 cm, bevorzugt 10 - 25 cm, besonders bevorzugt 15 - 20 cm betragen. Die Abschirmung der UV-Lampen zur Vermeidung von Strahlungsaustritt kann dabei z.B. durch Verwendung eines entsprechend ausgekleideten Schutzgehäuses um die transportable Lampeneinheit oder mit Hilfe anderer, dem Fachmann bekannter Sicherheitsmaßnahmen, erfolgen.The substrate surface can be 5-50 cm, preferably 10-25 cm, particularly preferably 15-20 cm. The shielding of the UV lamps to prevent radiation leakage can be e.g. by using an appropriately lined protective housing around the transportable lamp unit or with the help of other safety measures known to the person skilled in the art.
Die Bestrahlungsdauer liegt insgesamt im Bereich weniger Sekunden, beispielsweise im Bereich von 3 Millisekunden bis 400 Sekunden, bevorzugt von 4 bis 160 Sekunden, je nach Anzahl der gewählten Blitzentladungen. Die Blitze können beispielsweise ca. alle 4 Sekunden ausgelöst werden. Die UV-Blitzlampen sind jederzeit sofort einsetzbereit, d.h. sie bedürfen keiner Einbrennzeit und können zwischen zwei zeitlich etwas auseinanderliegenden Härtungs- bzw. Bestrahlungsvorgängen ausgeschaltet bleiben, ohne daß sich beim erneuten Bestrahlungsvorgang durch eine Einbrennphase Zeiteinbußen ergeben.The total irradiation time is in the range of a few seconds, for example in the range from 3 milliseconds to 400 seconds, preferably from 4 to 160 seconds, depending on the number of flash discharges selected. The flashes can be triggered, for example, every 4 seconds. The UV flash lamps are ready for use at any time, i.e. they do not require a baking time and can remain switched off between two curing or irradiation processes that are somewhat separated in time, without the loss of time resulting from a baking phase during the renewed irradiation process.
Sind in den erfindungsgemäß einsetzbaren Basislacken neben den strahlenhärtbaren Bindemitteln weitere physikalisch trocknende und/oder chemisch vernetzbare Bindemittel enthalten, so reichen die mittels der UV-Bestrahlung (UV-Blitzlampen) erzeugten Temperaturen auf der Beschichtung im allgemeinen aus, um die zusätzlichen vorhandenen Bindemittel auszuhärten. Ein separater Härtungsschritt ist nicht erforderlich. Im erfindungsgemäßen Verfahren wird auf die Basislackschicht entweder nach vollständiger Härtung oder naß-in-naß, gegebenenfalls nach kurzem Ablüften, ein Klarlacküberzug aufgebracht. Als Klarlacke sind alle in der Fahrzeuglackierung, insbesondere der Reparaturlackierung, üblichen und dem Fachmann bekannten lösemittel- oder wasserbasierenden Klarlacke geeignet. Beispiele hierfür sind lösemittelbasierende oder wäßrige Klarlacke auf Basis hydroxylgruppenhaltiger und/oder aminogruppenhaltiger Bindemittel und Polyisocyanatvernetzer sowie auf Basis aminogruppenhaltiger und acryloylfunktioneller Bindemittel. Die Härtung der Klarlackschicht kann bei Raumtemperatur oder forciert bei beispielsweise 40 - 80 °C erfolgen. Bevorzugt werden im erfindungsgemäßen Verfahren lösemittelbasierende oder wäßrigeIn addition to the radiation-curable binders, there are further physically drying and / or chemically crosslinkable in the basecoats which can be used according to the invention Containing binders, the temperatures generated by means of UV radiation (UV flash lamps) on the coating are generally sufficient to cure the additional binders present. A separate hardening step is not necessary. In the process according to the invention, a clear lacquer coating is applied to the basecoat film either after it has completely hardened or wet-on-wet, if appropriate after briefly flashing off. Suitable clearcoats are all solvent-based or water-based clearcoats which are customary in vehicle painting, in particular repair painting, and are known to the person skilled in the art. Examples of this are solvent-based or aqueous clear lacquers based on binders containing hydroxyl groups and / or amino groups and polyisocyanate crosslinkers and on binders based on amino groups and acryloyl-functional binders. The clearcoat layer can be cured at room temperature or forced at, for example, 40-80 ° C. Solvent-based or aqueous are preferred in the process according to the invention
Klarlackbeschichtungsmittel auf Basis von hydroxylgruppenhaltigen Bindemitteln und Polyisocyanatvernetzern eingesetzt.Clear coating compositions based on binders containing hydroxyl groups and polyisocyanate crosslinkers.
Besonders bevorzugt werden im erfϊndungsgemäßen Verfahren im Basislack radikalisch härtbare aliphatische Polyurethan(meth)acrylate und/oder aliphatische (meth)acrylfunktionelle Poly(meth)acrylate eingesetzt und als Klarlack auf Lösemittel basierende oder wäßrige Klarlacke auf Basis von hydroxylgruppenhaltigen Bindemitteln und Polyisocyanatvernetzern.In the process according to the invention, it is particularly preferred to use free-radically curable aliphatic polyurethane (meth) acrylates and / or aliphatic (meth) acrylic-functional poly (meth) acrylates and as clear lacquer based on solvent-based or aqueous clear lacquers based on binders containing hydroxyl groups and polyisocyanate crosslinkers.
Eine weitere bevorzugte Ausführungsform des erfindungsgemäßen Verfahrens besteht darin, als Klarlack einen solchen einzusetzen, der mittels energiereicher Strahlung härtbare Bindemittel enthält. Bei den mittels energiereicher Strahlung härtbarenA further preferred embodiment of the process according to the invention consists in using as clearcoat one which contains binders curable by means of high-energy radiation. For those curable by means of high-energy radiation
Bindemitteln handelt es sich beispielsweise um die vorstehend bereits beschriebenen strahlenhärtbaren Bindemittel, die im Basislack eingesetzt werden können. Besonders bevorzugt werden im Basislack und im Klarlack mittels energiereicher Strahlung härtbare Bindemittel auf Basis von aliphatischen Polyurethan(meth)acrylaten und/oder (meth)acrylfunktionellen Poly(meth)acrylaten eingesetzt. Der Klarlack kann naß-in- naß, gegebenenfalls nach kurzem Ablüften, auf den unausgehärteten Basislack aufgebracht werden. Dann erfolgt die Bestrahlung mit UV-Strahlen, wobei Basislack und Klarlack in einem Arbeitsschritt gemeinsam gehärtet werden. Es ist jedoch auch möglich, zunächst den Basislack mit der entsprechend notwendigen Anzahl von Blitzentladungen zwischenzuhärten oder vollständig zu härten, anschließend den Klarlack zu applizieren und der UV-Strahlung auszusetzen. Werden im erfindungsgemäßen Verfahren strahlenhärtbare Klarlacke eingesetzt, können vorteilhafterweise neben den für einen Klarlack üblichen Additiven zur Erhöhung der Kratzfestigkeit spezielle gecoatete transparente Füllstoffe enthalten sein. Als Füllstoffe kommen hier z.B. micronisiertes Aluminiumoxid oder micronisiertes Siliciumoxid in Frage. Diese transparenten Füllstoffe sind mit Verbindungen gecoatet, die UV-härtbare Gruppen enthalten, z.B. mit acrylfunktionellen Silanen, und werden somit bei der Strahlen ärtung des Klarlackes mit einbezogen . Die Füllstoffe sind als Handelsprodukte, z.B. unter dem Namen AKTISIL*, erhältlich. Mit dem erfindungsgemäße Verfahren erhält man Mehrschichtüberzüge mit großer Härte, hoher Kratzfestigkeit und hohem Glanz. Die einzelnen Lackschichten zeigen eine sehr gute Zwischenschichthaftung, und Anlöseresistenz gegenüber darunter bzw. darüberliegenden Lackschichten. Besonders gut ausgeprägt sind letztgenannte Eigenschaften, wenn im Mehrschichtaufbau neben dem Basislack auch die Klarlackschicht mittels energiereicher Strahlung härtbare Bindemittel enthält und für beide Lackschichten die gleichen strahlenhärtbaren Bindemittel und/oder Reaktivverdünner eingesetzt werden.Binders are, for example, the radiation-curable binders already described above, which can be used in the basecoat. Binders based on aliphatic polyurethane (meth) acrylates and / or (meth) acrylic-functional poly (meth) acrylates are particularly preferably used in the basecoat and in the clearcoat by means of high-energy radiation. The clear lacquer can be applied wet-on-wet, if necessary after briefly flashing off, to the uncured base lacquer. Then the irradiation with UV rays takes place, with basecoat and clearcoat be hardened together in one work step. However, it is also possible to first harden or completely harden the basecoat with the corresponding number of flash discharges, then apply the clearcoat and expose it to UV radiation. If radiation-curable clearcoats are used in the process according to the invention, special coated transparent fillers can advantageously be present in addition to the additives customary for a clearcoat to increase the scratch resistance. Fillers that can be used here are, for example, micronized aluminum oxide or micronized silicon oxide. These transparent fillers are coated with compounds that contain UV-curable groups, for example with acrylic-functional silanes, and are therefore included in the radiation curing of the clear lacquer. The fillers are available as commercial products, for example under the name AKTISIL * . The process according to the invention gives multilayer coatings with great hardness, high scratch resistance and high gloss. The individual layers of paint show very good interlayer adhesion and resistance to dissolving of the paint layers below or above. The latter properties are particularly pronounced if, in addition to the basecoat, the clearcoat layer also contains binders curable by means of high-energy radiation in the multilayer structure and the same radiation-curable binders and / or reactive thinners are used for both paint layers.
Die mit dem erfindungsgemäßen Verfahren erhaltenen Beschichtungen entsprechen ansonsten den Anforderungen an einen Reparaturlackaufbau auf dem Gebiet der Fahrzeuglackierung. Die Trocknung bzw. Härtung der Beschichtungen, insbesondere des Basislack/Klarlack-Aufbaus erfolgt im Vergleich zu in üblicher Weise getrockneten bzw. gehärteten Reparaturlackaufbauten in stark verkürzter Zeit.The coatings obtained with the method according to the invention otherwise meet the requirements for a refinish paint system in the field of vehicle painting. The drying or hardening of the coatings, in particular the basecoat / clearcoat structure, takes place in a greatly reduced time compared to repair lacquer structures which have been dried or hardened in the customary manner.
Beispielsweise ist es möglich, den Trocknungs- bzw. Härtungsprozeß für den Basislack/Klarlackaufbau innerhalb von ca. 5 - 15 Minuten, bevorzugt 5 - 10 Minuten, zu beenden. Ein weiterer Vorteil des erfindungsgemäßen Verfahrens besteht darin, daß in solchen Fällen, wo aus technologischen oder ökonomischen Gründen auf einen Klarlack imFor example, it is possible to end the drying or curing process for the basecoat / clearcoat structure within about 5 to 15 minutes, preferably 5 to 10 minutes. Another advantage of the method according to the invention is that in cases where, for technological or economic reasons, on a clear coat in
Mehrschichtaufbau verzichtet werden muß bzw. soll, z.B. bei der Lackierung von Fahrzeuginnenbereichen, wie Motorraum, Kofferraum, Türfalze, oder bei der Lackierung strukturierter Kunststoffoberflächen, problemlos der Klarlack weggelassen werden kann. Der mittels energiereicher Strahlung gehärtete Basislack erfüllt ohne weiteres und ohne jegliche Modifizierung die Funktion des Klarlackes, z.B. bezüglich Härte und Kratzfestigkeit. Das erfmdungsgemäße Verfahren kann vorteilhaft eingesetzt werden in derMulti-layer construction must or should be dispensed with, for example in the painting of vehicle interior areas, such as the engine compartment, trunk, door rebates, or in the Painting textured plastic surfaces, the clear coat can be easily omitted. The basecoat hardened by means of high-energy radiation fulfills the function of the clearcoat easily and without any modification, for example with regard to hardness and scratch resistance. The method according to the invention can advantageously be used in the
Fahrzeugreparaturlackierung, insbesondere von Fahrzeugteilen, kleineren Schadstellen und zum Spotrepair.Vehicle refinishing, especially of vehicle parts, smaller damaged areas and for spot repair.
Die Erfindung soll an Hand der folgenden Beispiele erläutert werden.The invention is illustrated by the following examples.
BeispieleExamples
Herstellung eines BasislackesProduction of a basecoat
Folgende Komponenten wurden miteinander vermischt und mittels Schnellrührer einige Minuten dispergiert (alle Angaben beziehen sich auf das Gewicht):The following components were mixed together and dispersed for a few minutes using a high-speed stirrer (all information relates to the weight):
476 Teile eines handelsüblichen aliphatischen Polyurethanacrylates 13 Teile eines handlsüblichen Verlaufsmittels 223 Teile Titandioxid476 parts of a commercially available aliphatic polyurethane acrylate 13 parts of a commercially available leveling agent 223 parts of titanium dioxide
25 Teile einer Mischung handelsüblicher Photoinitiatoren (Arylphosphinoxid- und Acetophenonderivate)25 parts of a mixture of commercially available photoinitiators (arylphosphine oxide and acetophenone derivatives)
110 Teile Butylacetat110 parts of butyl acetate
Herstellung eines KlarlackesProduction of a clear coat
Folgende Komponenten wurden miteinander vermischt und mittels Schnellrührer einige Minuten dispergiert (alle Angaben beziehen sich auf das Gewicht):The following components were mixed together and dispersed for a few minutes using a high-speed stirrer (all information relates to the weight):
114 Teile eines handelsüblichen aliphatischen Polyurethanacrylates 0,3 Teile eines handelsüblichen Verlaufsmittels114 parts of a commercially available aliphatic polyurethane acrylate 0.3 parts of a commercially available leveling agent
7,2 Teile einer Mischung handelsüblicher Photoinitiatoren (Arylphosphinoxid- und Acetophenonderivate) 44 Teile Butylacetat7.2 parts of a mixture of commercially available photoinitiators (arylphosphine oxide and acetophenone derivatives) 44 parts of butyl acetate
1 Teil eines handelsüblichen Lichtschutzmittels (HALS-Typ) 1 Teil eines handelsüblichen UV-Absorbers (Benztriazol-Typ) Erstellung eines Mehrschichtaufbaus1 part of a commercially available light stabilizer (HALS type) 1 part of a commercially available UV absorber (benzotriazole type) Creation of a multilayer structure
Der wie vorstehend beschrieben hergestellte Basislack wurde auf KTL-grundierte und mit üblichen lösemittelbasierenden 2K-Polyurethanfüllern beschichtete Bleche in einer resultierenden Trockenfilmschichtdicke von ca. 60 μm aufgebracht. Nach kurzerThe basecoat produced as described above was applied to KTL-primed and coated with customary solvent-based two-component polyurethane fillers in a resulting dry film layer thickness of approx. 60 μm. After short
Ablüftzeit bei Raumtemperatur wird die Basislackschicht der Bestrahlung durch eine UV-Blitzlampe (3500 Ws) ausgesetzt. Es wird mit 20 Blitzen (ca. 80 s) bestrahlt.Flash-off at room temperature exposes the basecoat to radiation from a UV flash lamp (3500 Ws). It is irradiated with 20 flashes (approx. 80 s).
Anschließend wird in einer ersten Variante der wie vorstehend beschrieben hergestellte Klarlack in einer resultierenden Trockenfilmschichtdicke von ca. 60 μm aufgebracht. Nach kurzer Ablüftzeit bei Raumtemperatur wird die Klarlackschicht der Bestrahlung durch eine UV-Blitzlampe (3500 Ws) ausgesetzt. Es wird mit 20 Blitzen (ca. 80 s) bestrahlt.Subsequently, in a first variant, the clear lacquer produced as described above is applied in a resulting dry film layer thickness of approximately 60 μm. After a short flash-off time at room temperature, the clear lacquer layer is exposed to the radiation by a UV flash lamp (3500 Ws). It is irradiated with 20 flashes (approx. 80 s).
In einer zweiten Varinate wird der ausgehärtete Basislack mit einem lösemittelbasierenden üblichen 2K-Polyurethan-Klarlack überlackiert und in üblicher Weise gehärtet.In a second varinate, the cured basecoat is overcoated with a solvent-based, conventional 2-component polyurethane clearcoat and cured in the customary manner.
Nachfolgend sind die Ergebnisse der lacktechnischen Untersuchungen dargestellt:The results of the paint tests are shown below:
Eigenschaft erfindungsgemäßer Mehr Schichtaufbau ausProperty of multi-layer structure according to the invention
UV-Basislack/UN-Klarlack UV-Basislack/2K-KlarlackUV basecoat / UN clearcoat UV basecoat / 2K clearcoat
Beständigkeit (1) gegenüber:Resistance (1) to:
Kraftstoff 0 3-4Fuel 0 3-4
Baumharz 0-1 2Tree resin 0-1 2
Pankreatin 3 4Pancreatin 3 4
HC1 0 0HC1 0 0
HsSO, 10 %ig 0 0HsSO, 10% 0 0
ΝaOH 0 0ΝaOH 0 0
Feucht/Warm-Test (2) (3) 0/0Wet / warm test (2) (3) 0/0
Haftung (4) 0-1Liability (4) 0-1
Haftung (4) nachLiability (4) after
Feucht/Warm-Test (2) 0 (1) VDA-Test entsprechend VDA-Prüfblatt 621/612Wet / warm test (2) 0 (1) VDA test according to VDA test sheet 621/612
(2) Feucht/Warm-Test nach DIN 50017(2) Wet / warm test according to DIN 50017
(3) Beurteilung der Blasenbildung nach DIN 53209(3) Assessment of blistering according to DIN 53209
(4) Gitterschnitt in Anlehnung an DIN 53151 (4) Cross-cut based on DIN 53151

Claims

Patentansprüche claims
1. Verfahren zur Herstellung einer mehrschichtigen Lackierung, bei dem auf ein gegebenenfalls mit einem Grundierungs- und/oder Füllerbeschichtungsmittel und/oder weiteren Beschichtungsmitteln vorbeschichtetes Substrat ein farb- und/oder effektgebendes Basislackbeschichtungsmittel aufgebracht wird und anschließend auf die färb- und/oder effektgebende Basislackschicht eine1. A process for producing a multi-layer coating, in which a color and / or effect basecoat coating agent is applied to a substrate which may have been precoated with a primer and / or filler coating agent and / or other coating agents and then onto the coloring and / or effect basecoat layer a
Klarlackschicht appliziert wird, dadurch gekennzeichnet, daß als färb- und/oder effektgebendes Basislackbeschichtungsmittel ein solches verwendet wird, das unter Einwirkung energiereicher Strahlung durch radikalische und/oder kanonische Polymerisation härtbare Bindemittel enthält.Clear lacquer layer is applied, characterized in that the coloring and / or effect-imparting basecoat coating agent used is one which contains binders curable under the action of high-energy radiation by radical and / or canonical polymerization.
2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß die Härtung mittels gepulster UV-Strahlung erfolgt.2. The method according to claim 1, characterized in that the curing is carried out by means of pulsed UV radiation.
3. Verfahren nach Anspruch 1 oder 2 dadurch gekennzeichnet, daß als durch radikalische Polymerisation härtbare Bindemittel aliphatische3. The method according to claim 1 or 2, characterized in that as a curable by radical polymerization binder aliphatic
Polyurethan(meth)acrylate und/oder aliphatische (meth)acrylfunktionelle (Meth)acrylcopolymere verwendet werden.Polyurethane (meth) acrylates and / or aliphatic (meth) acrylic functional (meth) acrylic copolymers can be used.
4. Verfahren nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß auch für die Klarlackschicht ein durch energiereiche Strahlung härtbares Bindemittel eingesetzt wird.4. The method according to any one of claims 1 to 3, characterized in that a binder curable by high-energy radiation is also used for the clear coat.
5. Verfahren nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß es zur Reparaturlackierung von Substraten durchgeführt wird.5. The method according to any one of claims 1 to 4, characterized in that it is carried out for the refinishing of substrates.
6. Verfahren nach Anspruch 5, dadurch gekennzeichnet, daß es zur6. The method according to claim 5, characterized in that it for
Reparaturlackierung von Kraftfahrzeugkarossen oder deren Teilen durchgeführt wird. Refinishing of vehicle bodies or their parts is carried out.
EP98961139A 1997-11-20 1998-11-05 Method for multi-layered coating of substrates Ceased EP1032475A1 (en)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
DE19751479 1997-11-20
DE1997151479 DE19751479A1 (en) 1997-11-20 1997-11-20 Multilayer coating system comprising base and clear lacquer layers cured by high energy radiation
DE1997157083 DE19757083A1 (en) 1997-12-20 1997-12-20 Multilayer coating system comprising base and clear lacquer layers cured by high energy radiation
DE19757083 1997-12-20
PCT/EP1998/007070 WO1999026732A1 (en) 1997-11-20 1998-11-05 Method for multi-layered coating of substrates

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EP1032475A1 true EP1032475A1 (en) 2000-09-06

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EP (1) EP1032475A1 (en)
JP (1) JP2001523572A (en)
CA (1) CA2310747A1 (en)
WO (1) WO1999026732A1 (en)

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US6534130B1 (en) 2003-03-18
CA2310747A1 (en) 1999-06-03
JP2001523572A (en) 2001-11-27
WO1999026732A1 (en) 1999-06-03

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