WO2000035598A1 - Method for multi-layer varnishing - Google Patents

Method for multi-layer varnishing Download PDF

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Publication number
WO2000035598A1
WO2000035598A1 PCT/EP1999/009064 EP9909064W WO0035598A1 WO 2000035598 A1 WO2000035598 A1 WO 2000035598A1 EP 9909064 W EP9909064 W EP 9909064W WO 0035598 A1 WO0035598 A1 WO 0035598A1
Authority
WO
WIPO (PCT)
Prior art keywords
radiation
irradiation
layer
curable
energy radiation
Prior art date
Application number
PCT/EP1999/009064
Other languages
German (de)
French (fr)
Inventor
Helmut Löffler
Karin Maag
Wolfgang Feyrer
Christine Kimpel
Jens Zeyen
Original Assignee
E.I. Du Pont De Nemours And Company, Inc.
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
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=7891216&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=WO2000035598(A1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by E.I. Du Pont De Nemours And Company, Inc. filed Critical E.I. Du Pont De Nemours And Company, Inc.
Priority to DK99962155T priority Critical patent/DK1152841T3/en
Priority to EP99962155A priority patent/EP1152841B2/en
Priority to CA002347868A priority patent/CA2347868C/en
Priority to JP2000587898A priority patent/JP2002532234A/en
Priority to AT99962155T priority patent/ATE219392T1/en
Priority to DE59901829T priority patent/DE59901829D1/en
Publication of WO2000035598A1 publication Critical patent/WO2000035598A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • 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
    • B05D7/574—Three layers or more the last layer being a clear coat at least some layers being let to dry at least partially before applying the next layer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
    • B05D3/02—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by baking
    • B05D3/0209—Multistage baking
    • 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
    • B05D7/577—Three layers or more the last layer being a clear coat some layers being coated "wet-on-wet", the others not
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
    • B05D3/02—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by baking
    • B05D3/0254—After-treatment
    • B05D3/0263—After-treatment with IR heaters
    • 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
    • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
    • B05D7/50—Multilayers
    • B05D7/52—Two layers
    • B05D7/54—No clear coat specified
    • B05D7/544—No clear coat specified the first layer is let to dry at least partially before applying the second layer

Definitions

  • the invention relates to a method for multi-layer coating of substrates using radiation-curable coating agents.
  • the method can advantageously be used in vehicle and industrial painting, preferably in vehicle refinishing.
  • UV technology for coating and hardening has long been state of the art, particularly in the wood coating industry. However, it has also become known in other fields of application, such as in vehicle painting, to use coating compositions curable by means of high-energy radiation.
  • the advantages of radiation-curable coating agents are also used here, e.g. the very short curing times, the low solvent emissions of the coating agents and the very good hardness of the coatings obtained from them.
  • DE-A-196 35 447 describes a process for the production of a multi-layer refinish, a coating agent being applied as a clear coat or pigmented top coat which contains binders which can only be polymerized by UV radiation.
  • the applied coating agent is UV-irradiated with UV flash lamps.
  • EP-A-0 540 884 describes a process for the production of a multi-layer finish for automotive serial painting by applying a clear coat to a dried or hardened basecoat, the clearcoat containing free-radical curing curable binders and the clearcoat being cured by means of UV radiation .
  • the Klariack is applied when illuminated with light with a wavelength of over 550 "nm or in the absence of light.
  • Coating agents which can be cured by means of high-energy radiation and which contain binders which can cure by means of high-energy radiation and additionally via a further crosslinking mechanism have also been described.
  • DE-A-28 09 715 specifies binders curable by means of high-energy radiation which are based on an NCO- and acryloyl-functional urethane compound, prepared from a hydroxyalkyl ester of (meth) acrylic acid and a polyisocyanate, and on a polyfunctional hydroxyl compound.
  • EP-A-0 000 407 describes coating compositions curable by means of high-energy radiation based on an OH-functional polyester resin esterified with acrylic acid, a vinyl compound and a polyisocyanate.
  • a first curing step the irradiation with UV light takes place and in a second curing step, the final curing takes place at temperatures of 130 to 200 ° C.
  • German patent application P 198 18 735 proposes coating compositions which are curable by means of high-energy radiation and which contain, as binders, compounds A) with free-radically polymerizable double bonds and other functional groups which are reactive in the sense of an addition and / or condensation reaction, and compounds B) with radicals polymerizable double bonds and other functional groups reactive in the sense of an addition and / or condensation reaction, the latter being said to be reactive towards the additional reactive groups of the compounds A).
  • the coatings obtained can be heated to higher temperatures, e.g. Exposed to 30 to 120 ° C.
  • the object of the invention was therefore to provide a process for multi-layer vehicle painting, in particular for multi-layer vehicle refinishing, using at least partially radiation-curable coating agents, with which coatings are obtained which are free from cracks and have good adhesion to the substrate.
  • the coatings obtained are said to have very good chemical and weather resistance and good sandability. They should also show sufficient flexibility even with a high degree of networking.
  • the coatings should also show a perfect optical appearance.
  • the object is achieved by the process for multi-layer painting, which forms an object of the invention, by applying one or more filler layers and / or further layers, which can be conventional intermediate layers, for example, to a possibly precoated substrate, and then applying a top coat layer from one Basecoat / clearcoat structure or from a pigmented single-layer topcoat, at least one of the layers of the multi-layer structure being produced from a coating agent which is at least partially curable by means of high-energy radiation, which is characterized in that after application of the coating agent or agents which are at least partially curable by means of high-energy radiation (see ) first exposure to infrared radiation (TR radiation) and then exposure to high-energy radiation, preferably ultraviolet radiation (UN radiation), the exposure to IR radiation Radiation can at least partially overlap the subsequent irradiation with high-energy radiation.
  • "UV radiation in particular, but also, for example, electron radiation can be used as high-energy radiation.
  • a flash-off phase is preferably granted.
  • it can be a venting of 5 to 15 minutes, preferably 5 to 10 minutes at room temperature. Irradiation is then carried out.
  • the coating compositions which are at least partially curable by means of high-energy radiation in the process according to the invention can be aqueous, diluted with solvents or free from solvents and water.
  • the coating compositions can be completely or only partially curable by means of high-energy radiation, preferably by means of UV radiation.
  • Coating agents curable by means of high-energy radiation are, in particular, cationically and / or radically curing coating agents known to the person skilled in the art. Radically curing coating compositions are preferred. When high-energy radiation acts on these coating compositions, radicals are generated in the coating composition, which trigger crosslinking by radical polymerization of olefinic double bonds.
  • the free-radically curing coating compositions which can be used preferably contain customary prepolymers, such as poly- or oligomers, which have free-radically polymerizable olefinic double bonds, in particular in the form of (meth) acryloyl groups in the molecule.
  • the prepolymers can be used in combination with conventional reactive diluents, i.e. reactive liquid monomers.
  • prepolymers or oligomers are (meth) acrylic-functional (meth) acrylic copolymers, epoxy resin (meth) acrylates, polyester (meth) acrylates, polyether (meth) acrylates, polyurethane (meth) acrylates, unsaturated polyesters, unsaturated polyurethanes or silicone (meth) acrylates with number average molecular masses (Mn) preferably in the range from 200 to 10,000, particularly preferably from 500 to 3000 and with an average of 2 to 20, preferably 3 to 10, radically polymerizable, olefinic double bonds per molecule.
  • Mn number average molecular masses
  • (Meth) acrylic here means acrylic and / or methacrylic.
  • reactive diluents are used, for example, in amounts of 1 to 50% by weight, preferably 5 to 30% by weight, based on the total weight of prepolymers and reactive diluents. These are defined low-molecular compounds that can be mono-, di- or polyunsaturated.
  • reactive diluents are: (meth) acrylic acid and its esters, maleic acid and its half esters, vinyl acetate, vinyl ether, substituted vinyl ureas, ethylene and propylene glycol di (meth) acrylate, 1,3- and 1,4-butanediol di (meth) acrylate, Vinyl (meth) acrylate, allyl (meth) acrylate, glycerol tri, di and mono (meth) acrylate, trimethylolpropane tri, di and mono (meth) acrylate, styrene, vinyl toluene, divinyl benzene, pentaerythritol tri and - tetra (meth) acrylate, di- and tripropylene glycol di (meth) acrylate, hexanediol di (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 thinners.
  • the free radical curing coating compositions contain photoinitiators, e.g. in amounts of 0.1 to 5% by weight, preferably 0.5 to 3% by weight, based on the sum of free-radically polymerizable prepolymers, reactive diluents and photoinitiators.
  • photoinitiators such as benzoin and derivatives, acetophenone and derivatives, e.g. 2,2-diacetoxyacetophenone, benzophenone and derivatives, thioxanthone and derivatives, anthraquinone, 1-benzoylcyclohexanol, organophosphorus compounds, e.g. Acylphosphine oxides.
  • the photoinitiators can be used alone or in combination.
  • other synergistic components e.g. tertiary amines can be used.
  • the coating compositions which can be at least partially hardened by means of high-energy radiation in the process according to the invention preferably contain one or more further binders in addition to the binder system which is curable by means of high-energy radiation.
  • the other binders which may additionally be present, are preferably conventional binder systems which can be hardened by means of addition and / or condensation reactions. However, they can also be conventional physically drying binder systems or combinations of the two binder systems mentioned. It is also possible that this is by means of high energy Radiation-curable binder system in addition to the radically polymerizable double bonds for crosslinking by addition and / or condensation reactions has groups.
  • lacquer chemical crosslinking reactions known to the person skilled in the art, such as, for example, the ring-opening addition of an epoxy group to a carboxyl group to form an ester and a hydroxyl group, the addition of a hydroxyl group to an isocyanate group to form a Urethane group, the reaction of a hydroxyl group with a blocked isocyanate group to form a urethane group and elimination of the blocking agent, the reaction of a hydroxyl group with an N-methylol group with elimination of water, the reaction of a hydroxyl group with an N-methylol ether group with elimination of the etherification alcohol, the transesterification reaction of a hydroxyl group with an ester group with elimination of the esterification alcohol, the re-uramation reaction of a hydroxyl group with a carbamate group with alcohol elimination, the reaction of a carbamate group with an N-methylo lether group with elimination of
  • Functional groups are preferably contained in the binder system, which enable crosslinking at low temperatures, for example at 20 to 80 ° C. It can particularly preferably be hydroxyl and isocyanate groups.
  • the functional groups, in particular the hydroxyl groups and isocyanate groups, can each be present in the binder curable by means of high-energy radiation and / or in a separate binder.
  • polyurethane (meth) acrylates, polyester (meth) acrylates and / or (meth) acryloyl-functional poly (meth) acrylates can be used in the clear coat, basecoat or single-layer topcoat and in the filler or other layers, such as intermediate layers, preferably epoxy (meth) acrylates.
  • Particularly good results are obtained if the (meth) acryloyl-functional binders mentioned above are combined with binders which are based on a crosslinking mechanism between hydroxyl and isocyanate groups.
  • the hydroxyl and / or isocyanate groups can also be present in the (meth) acryloyl-functional binder (s).
  • Binder systems which contain (meth) acryloyl and OH-functional components and polyisocyanates are particularly preferred and advantageously to be used, it being possible for the (metfriacryloyl and OH groups to be present in one and / or different binder components, and also binder systems comprising A ) one or more compounds which have free-radically polymerizable double bonds and which additionally contain at least one further functional group which is reactive in the sense of an addition and / or condensation reaction, and B) one or more compounds which have free-radical polymerizable double bonds which additionally contain at least one further in the sense of an addition and / or contain a condensation reaction reactive functional group, the additional reactive functional group being complementary or reactive towards the additional reactive functional groups of component A).
  • one or more monomeric, oligomeric and / or polymeric compounds with at least one functional group from component A) or component B) which is present in addition to the radical-polymerizable double bonds can optionally also be reactive in the sense of an addition and / or condensation reaction Group.
  • the at least partially curable coating compositions which can be used in the process according to the invention can contain additional components which are customary for the coating formulation.
  • the additives are the usual additives that can be used in the paint sector. Examples of such additives are leveling agents, anti-cratering agents, anti-foaming agents, catalysts, adhesion promoters, rheology-influencing additives, thickeners, light stabilizers and emulsifiers.
  • the additives are used in customary amounts known to the person skilled in the art.
  • the coating compositions which can be used in the process according to the invention can contain proportions of organic solvents and / or water.
  • the solvents are common paint solvents. These can come from the manufacture of the binders ' originate or are added separately. Examples of such solvents are monohydric or polyhydric alcohols, for example propanol, butanol, hexanol; Glycol ethers or esters, for example diethylene glycol dialkyl ether, dipropylene glycol dialkyl ether, in each case with C1 to C6 alkyl, ethoxypropanol, butyl glycol; Glycols, for example ethylene glycol, propylene glycol and their oligomers, esters, for example butyl acetate and amyl acetate, N-methylpyrrolidone and ketones, for example methyl ethyl ketone, acetone, cyclohexanone; aromatic or aliphatic hydrocarbons, for example toluene,
  • the coating compositions which can be used in the process according to the invention can contain pigments and / or fillers. These are the usual fillers and organic or inorganic color and / or effect pigments and corrosion protection pigments that can be used in the paint industry.
  • 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: metal pigments, for example made of aluminum, copper or other metals; Interference pigments, such as metal oxide-coated metal pigments, for example titanium dioxide-coated or ischoxide-coated aluminum, coated mica, such as titanium dioxide-coated mica and graphite effect pigments.
  • fillers are silicon dioxide, aluminum silicate, barium sulfate and talc.
  • the coating compositions can advantageously contain special coated fillers to increase the scratch resistance.
  • Fillers that can be used here are, for example, micronized aluminum oxide or micronized silicon oxides. These fillers are coated with compounds which contain UV-curable groups, for example with acrylic-functional silanes, and are therefore included in the radiation curing of the coating composition.
  • UV-curable groups for example with acrylic-functional silanes
  • Such suitable particularly for clearcoats transparent fillers are available as commercial products, for example under the name AKTISIL ® available.
  • the general composition of the coating agents that can be used depends on which layer of the multilayer structure is to be created with the respective coating agent, ie whether it is, for example a clear coat, a basecoat or a filler or another common intermediate layer.
  • the coating compositions can be applied to various substrates in the process according to the invention.
  • Preferred substrates are metal or
  • Plastic substrates The application in the multilayer structure is carried out by customary methods, preferably by spray application.
  • the substrates can be precoated, for example provided with a customary primer layer.
  • TR radiators which are known to the person skilled in the art and are customary for drying the paint can be used.
  • the IR radiator is positioned in front of the substrate surface to be irradiated, for example at a distance of 20 to 70 cm.
  • the radiation duration with TR radiation can be, for example, 1 to 20 minutes. Depending on the radiation duration and
  • temperatures of, for example, 40 to 200 ° C. can be achieved on the substrate surface.
  • the settings should be made so that temperatures of, for example, 40 to 100 ° C are reached on the substrate surface.
  • Particularly good results are achieved if, after application, the radiation is not irradiated directly with TR radiation, but rather one
  • Flash-off phase follows. For example, it can be a venting of 5 to 15 minutes, preferably 5 to 10 minutes at room temperature.
  • the irradiation can be carried out with high-energy radiation, preferably with UV radiation.
  • the curing of the coating which is curable at least partially by means of high-energy radiation, preferably UV radiation, can preferably be carried out with UV radiation sources with emissions in the wavelength range from 180 to 420 nm, in particular from 200 to 400 nm.
  • UV radiation sources that can be used include high-pressure, medium-pressure and low-pressure mercury lamps.
  • the lamp length can vary. For example, lamps between 5 and 200 cm in length are common. Depending on the specific application and the radiation energy required, the lamp and reflector geometry can be coordinated with one another in the usual way.
  • the respective lamp power can vary, for example, between 20 and 250 W / cm (watts per cm lamp length). Lamps with powers between 80 and 120 W / cm are preferably used.
  • the mercury lamps can also be doped by introducing metal halides. Examples of doped emitters are iron or gallium mercury lamps.
  • UV radiation sources are gas discharge tubes, e.g. Xenon low pressure lamps, UV lasers, UV spot lamps, e.g. UV emitting diodes and black light tubes.
  • discontinuous UV radiation sources can also be used. These are preferably so-called high-energy flash devices (in short: UV flash lamps).
  • the UV flash lamps can contain a plurality of flash tubes, for example quartz tubes filled with inert gas such as xenon.
  • the UV flash lamps have, for example, an illuminance of at least 10 megalux, preferably from 10 to 80 megalux per flash discharge.
  • the energy per flash discharge can be, for example, 1 to 10 kJoules.
  • the UV radiation sources are generally integrated in a UV system, which normally consists of the UV radiation sources, the reflector system, the power supply, electrical controls, the shielding, the cooling system and the ozone extraction.
  • a UV system normally consists of the UV radiation sources, the reflector system, the power supply, electrical controls, the shielding, the cooling system and the ozone extraction.
  • Other arrangements are of course also possible, and individual components can also be omitted.
  • the exposure time to UV radiation can be, for example, in the range from 1 millisecond 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 Hardening can, for example, by. 1 to 40 successive lightning discharges.
  • the irradiation time can range, for example, from a few seconds to about 5 minutes, preferably less than 5 minutes.
  • the distance between the UV radiation sources and the substrate surface to be irradiated can be, for example, 5 to 60 cm.
  • the shielding of the UV radiation sources to avoid radiation leakage can e.g. by using an appropriately lined protective housing around a transportable lamp unit or with the help of other safety measures known to the person skilled in the art.
  • the process according to the invention for multi-layer painting which is characterized in that after application of the coating agent (s) at least partially curable by means of high-energy radiation, radiation with IR radiation and then radiation with high-energy radiation is carried out in various embodiments.
  • the UV radiation phase it is possible to connect the UV radiation phase to the completed IR radiation phase or to start the UV radiation with continuous IR radiation.
  • the IR and UV radiation phases can partially or completely overlap, i.e. the IR irradiation phase can be completed before or simultaneously with the termination of the UV irradiation phase.
  • IR radiation phase can be, for example, 0.5 to 30 minutes. Otherwise, the statements made above regarding IR radiation apply.
  • IR, UV and IR irradiation can be carried out in sequence, or the IR irradiation phase extends over the entire irradiation time, ie the IR irradiation is carried out before, during and also carried out after the UV irradiation phase.
  • the irradiation phases IR radiation and subsequent UV radiation can also be repeated several times as required.
  • the radiation duration per radiation interval and the total radiation duration can be varied.
  • Coupled radiation intervals IR and UV radiation in connection with the implementation of several spray coats, several work steps or in connection with the radiation curing of several successive layers of the multi-layer structure.
  • intermediate curing with IR irradiation and subsequent UV irradiation can take place in one spray pass, subsequently the coating agent is applied in one or more further spray passes and again IR and then UV Radiation.
  • This method of operation is, for example, when applying thicker layers, e.g. up to 400 ⁇ m, desired filler layers are particularly advantageous.
  • an at least partially radiation-curable basecoat in the multi-layer structure It is also possible to first apply an at least partially radiation-curable basecoat in the multi-layer structure and first to subject it to IR and then UV radiation. An at least partially radiation-curable clear lacquer can then be applied and again subjected to IR and then UV radiation. If necessary, a further TR irradiation can follow the UV irradiation in both cases.
  • the radiation curing of the individual layers of the multilayer structure and of the layers applied by means of a plurality of spray coats can each be carried out individually with different radiation intensities and with different irradiation times for each layer or together for two or more layers.
  • IR and UV lamps can be arranged alternately side by side in the device.
  • one or more layers of a customary multi-layer structure which can be at least partially hardened by means of high-energy radiation, can be hardened in the vehicle painting.
  • This can be, for example, a multilayer structure consisting of primer, filler, basecoat and clearcoat
  • One or more layers of the multilayer structure can be created from at least partially radiation-curable coating agents.
  • a filler layer (binder-based: 2-component polyurethane, solvent-based) was applied to a sheet coated by cathodic electrocoating (KTL) in a resulting dry film thickness of approx. 80 ⁇ m and cured at 60 ° C for 30 minutes after a short flash-off time at room temperature.
  • KTL cathodic electrocoating
  • a water-based lacquer (produced in accordance with DE-A-196 43 802, production example 4) was applied to the filler layer in a resulting dry film layer thickness of 13 to 15 ⁇ m. After a flash-off phase of 20 minutes at room temperature, the UV-curable clearcoat produced as described above was applied in a resulting dry film layer thickness of 40-50 ⁇ m.
  • the applied clear lacquer was subjected to IR radiation.
  • the irradiation time was 5 minutes.
  • the UV radiation was then carried out using a UV flash lamp (power 3500 Ws).
  • the irradiation was carried out with 30 flashes, which were triggered at intervals of approximately 4 s, at an object distance of approximately 20 cm.
  • Example 2 The procedure was analogous to Example 1, with the difference that after application of the clear lacquer, after a flash-off phase of 30 minutes at room temperature, the UV radiation was carried out directly with a UV flash lamp (power 3500 Ws). The UV radiation was carried out with 30 flashes, which were triggered at intervals of approx. 4 s, at an object distance of approx. 20 cm. Comparison of the paint results

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)
  • Paints Or Removers (AREA)
  • Medicinal Preparation (AREA)
  • Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
  • Nitrogen And Oxygen Or Sulfur-Condensed Heterocyclic Ring Systems (AREA)

Abstract

The invention relates to a method for multi-layer varnishing by applying filler layers and/or additional coating agent layers and by subsequently applying a coating layer of base coat/clear lacquer texture or of a pigmented finishing coat consisting of one layer onto a substrate. At least one of the layers is produced by a coating agent which is at least partially hardenable by means of radiation of high energy. After application of said coating agent, exposure to IR radiation and then to radiation of high energy are carried out.

Description

Verfahren zur MehrschichtiackierungMulti-layer painting process
Die Erfindung betrifft ein Verfahren zur Mehrschichtiackierung von Substraten unter Verwendung strahlungshärtbarer Beschichtungsmittel. Das Verfahren kann vorteilhaft Anwendung finden in der Fahrzeug- und Industrielackierung, bevorzugt in der Fahrzeugreparaturlackierung.The invention relates to a method for multi-layer coating of substrates using radiation-curable coating agents. The method can advantageously be used in vehicle and industrial painting, preferably in vehicle refinishing.
Die UV-Technologie bei der Beschichtung und Härtung ist insbesondere in der Holzbeschichtungsindustrie seit längerem Stand der Technik. Aber auch in anderen Anwendungsgebieten, so auch in der Fahrzeuglackierung, ist es bekannt geworden, mittels energiereicher Strahlung härtbare Beschichtungsmittel einzusetzen. Man nutzt auch hier die Vorteile strahlungshärtbarer Beschichtungsmittel, wie z.B. die sehr kurzen Härtungszeiten, die geringe Lösemittelemission der Beschichtungsmittel sowie die sehr gute Härte der daraus erhaltenen Beschichtungen.UV technology for coating and hardening has long been state of the art, particularly in the wood coating industry. However, it has also become known in other fields of application, such as in vehicle painting, to use coating compositions curable by means of high-energy radiation. The advantages of radiation-curable coating agents are also used here, e.g. the very short curing times, the low solvent emissions of the coating agents and the very good hardness of the coatings obtained from them.
Neben geeigneten strahlungshärtbaren Bindemitteln und Photoinitiatoren sind auch verschiedene Arten von Strahlungsquellen bekannt worden.In addition to suitable radiation-curable binders and photoinitiators, various types of radiation sources have also become known.
So beschreibt beispielsweise die DE-A- 196 35 447 ein Verfahren zur Herstellung einer mehrschichtigen Reparaturlackierung, wobei als Klarlack oder pigmentierter Decklack ein Beschichtungsmittel appliziert wird, das auschließlich durch UV-Strahlung radikalisch polymerisierbare Bindemittel enthält. Die UV-Bestrahlung des appiizierten Beschichtungsmittels erfolgt mit UV-Blitzlampen.For example, DE-A-196 35 447 describes a process for the production of a multi-layer refinish, a coating agent being applied as a clear coat or pigmented top coat which contains binders which can only be polymerized by UV radiation. The applied coating agent is UV-irradiated with UV flash lamps.
Die EP-A-0 540 884 beschreibt ein Verfahren zur Herstellung einer Mehrschichtiackierung für die Kraftfahrzeugserienlackierung durch Auftrag einer Klarlackschicht auf eine getrocknete bzw. gehärtete Basislackschicht, wobei das Klarlackbeschichrungsmittel durch radikalische Polymerisation härtbare Bindemittel enthält und die Härtung der Klarlackschicht mittels UV- Strahlung durchgeführt wird. Der Auftrag des Klariackes erfolgt bei Beleuchtung mit Licht einer Wellenlänge von über 550 "nm oder unter Ausschluß von Licht.EP-A-0 540 884 describes a process for the production of a multi-layer finish for automotive serial painting by applying a clear coat to a dried or hardened basecoat, the clearcoat containing free-radical curing curable binders and the clearcoat being cured by means of UV radiation . The Klariack is applied when illuminated with light with a wavelength of over 550 "nm or in the absence of light.
Es sind auch mittels energiereicher Strahlung härtbare Beschichtungsmittel beschrieben worden, welche Bindemittel enthalten, die mittels energiereicher Strahlung und zusätzlich über einen weiteren Vernetzungsmechanismus aushärten können.Coating agents which can be cured by means of high-energy radiation and which contain binders which can cure by means of high-energy radiation and additionally via a further crosslinking mechanism have also been described.
Zum Beispiel werden in der DE-A-28 09 715 mittels energiereicher Strahlung härtbare Bindemittel genannt, die auf einer NCO- und acryloylfunktionellen Urethanverbindung, hergestellt aus einem Hydroxyalkylester der (Meth)acrylsäure und einem Polyisocyanat, und auf einer polyfunktionellen Hydroxylverbindung basieren.For example, DE-A-28 09 715 specifies binders curable by means of high-energy radiation which are based on an NCO- and acryloyl-functional urethane compound, prepared from a hydroxyalkyl ester of (meth) acrylic acid and a polyisocyanate, and on a polyfunctional hydroxyl compound.
Die EP-A-0 000 407 beschreibt mittels energiereicher Strahlung härtbare Beschichtungsmittel auf Basis eines mit Acrylsäure veresterten OH-funktionellen Polyesterharzes, einer Vinylverbindung und eines Polyisocyanates. In einem ersten Härtungsschritt erfolgt die Bestrahlung mit UV-Licht und einem zweiten Härtungsschritt erfolgt die Endhärtung bei Temperaturen von 130 bis 200°C.EP-A-0 000 407 describes coating compositions curable by means of high-energy radiation based on an OH-functional polyester resin esterified with acrylic acid, a vinyl compound and a polyisocyanate. In a first curing step, the irradiation with UV light takes place and in a second curing step, the final curing takes place at temperatures of 130 to 200 ° C.
In der noch nicht offengelegten deutschen Patentanmeldung P 198 18 735 werden mittels energiereicher Strahlung härtbare Beschichtungsmittel vorgeschlagen, die als Bindemittel Verbindungen A) mit radikaiisch polymerisierbaren Doppelbindungen und weiteren im Sinne einer Additions- und/oder Kondensationsreaktion reaktiven funktioneilen Gruppen enthalten sowie Verbindungen B) mit radikalisch polymerisierbaren Doppelbindungen und weiteren im Sinne einer Additions- und/oder Kondensationsreaktion reaktiven funktionellen Gruppen, wobei letztere reaktiv sein sollen gegenüber den zusätzlichen reaktiven Gruppen der Verbindungen A). Zur vollständigen Aushärtung können die erhaltenen Beschichtungen nach der UV-Bestrahlung höheren Temperaturen von z.B. 30 bis 120°C ausgesetzt werden.German patent application P 198 18 735, which has not yet been disclosed, proposes coating compositions which are curable by means of high-energy radiation and which contain, as binders, compounds A) with free-radically polymerizable double bonds and other functional groups which are reactive in the sense of an addition and / or condensation reaction, and compounds B) with radicals polymerizable double bonds and other functional groups reactive in the sense of an addition and / or condensation reaction, the latter being said to be reactive towards the additional reactive groups of the compounds A). For complete curing, the coatings obtained can be heated to higher temperatures, e.g. Exposed to 30 to 120 ° C.
Mit den vorstehend genannten Verfahren zur mehrschichtigen Fahrzeuglackierung unter Verwendung mittels energiereicher Strahlung härtbarer Bindemittel werden jedochHowever, with the above-mentioned processes for multi-layer vehicle painting using binders curable by means of high-energy radiation
Beschichtungen erhalten, die in verschiedener Hinsicht noch verbesserungsbedürftig sind. Die Beschichtungen zeigen noch Schwächen bezüglich Bewitterungs- und Chemikalienbeständigkeit und weisen eine unbefriedigende Schleifbarkeit auf. Des Weiteren kommt es bei den mittels energiereicher Strahlung härtbaren Beschichtungsmitteln durch den Härtungsprozeß zu einem Volumenschrumpf der aufgebrachten Beschichtung, was zu Spannungen und Rißbildung im Film fuhrt. Enthaftungserscheinungen zum Untergrund können die Folge sein. Das Problem der Rißbildung und mangelnden Zwischenschichthaftung ist noch nicht zufriedenstellend gelöst worden.Get coatings that need to be improved in various ways. The coatings still show weaknesses with regard to weathering and chemical resistance and have unsatisfactory sandability. Of Furthermore, in the case of the coating compositions curable by means of high-energy radiation, the curing process leads to a volume shrinkage of the applied coating, which leads to tension and crack formation in the film. This can result in signs of release from the substrate. The problem of cracking and lack of interlayer adhesion has not yet been satisfactorily resolved.
Aufgabe der Erfindung war es daher, ein Verfahren zur mehrschichtigen Fahrzeuglackierung, insbesondere zur mehrschichtigen Fahrzeugreparaturlackierung, unter Verwendung zumindest teilweise strahlungshärtbarer Beschichtungsmittel bereitzustellen, mit welchem Beschichtungen erhalten werden, die frei sind von Rißbildungen und eine gute Haftung zum Untergrund aufweisen. Die erhaltenen Beschichtungen sollen eine sehr gute Chemikalien- und Witterungsbeständigkeit sowie eine gute Schleifbarkeit aufweisen. Sie sollen auch bei hoher Vernetzungsdichte eine ausreichende Flexibilität zeigen. Die Beschichtungen sollen außerdem ein einwandfreies optisches Aussehen zeigen.The object of the invention was therefore to provide a process for multi-layer vehicle painting, in particular for multi-layer vehicle refinishing, using at least partially radiation-curable coating agents, with which coatings are obtained which are free from cracks and have good adhesion to the substrate. The coatings obtained are said to have very good chemical and weather resistance and good sandability. They should also show sufficient flexibility even with a high degree of networking. The coatings should also show a perfect optical appearance.
Die Aufgabe wird gelöst durch das einen Gegenstand der Erfindung bildende Verfahren zur Mehrschichtiackierung durch Auftrag einer oder mehrerer Füllerschichten und/oder weiterer Schichten, bei denen es sich beispielsweise um übliche Zwischenschichten handeln kann, auf ein gegebenenfalls vorbeschichtetes Substrat, und anschließenden Auftrag einer Decklackschicht aus einem Basislack/Klarlack-Aufbau oder aus einem pigmentierten Einschichtdecklack, wobei mindestens eine der Schichten des Mehrschichtaufbaus aus einem mittels energiereicher Strahlung zumindest teilweise härtbaren Beschichtungsmittel erstellt wird, welches dadurch gekennzeichnet ist, daß nach Applikation des oder der mittels energiereicher Strahlung zumindest teilweise härtbaren Beschichtungsmittel(s) zunächst eine Bestrahlung mit Infrarot- Strahlung (TR- Strahlung) und anschließend eine Bestrahlung mit energiereicher Strahlung, bevorzugt Ultraviolett- Strahlung (UN- Strahlung) erfolgt, wobei die Bestrahlung mit IR- Strahlung die anschließende Bestrahlung mit energiereicher Strahlung zumindest teilweise überlappen kann. "Als energiereiche Strahlung kann insbesondere UV-Strahlung, aber auch beispielsweise Elektronenstrahlung eingesetzt werden.The object is achieved by the process for multi-layer painting, which forms an object of the invention, by applying one or more filler layers and / or further layers, which can be conventional intermediate layers, for example, to a possibly precoated substrate, and then applying a top coat layer from one Basecoat / clearcoat structure or from a pigmented single-layer topcoat, at least one of the layers of the multi-layer structure being produced from a coating agent which is at least partially curable by means of high-energy radiation, which is characterized in that after application of the coating agent or agents which are at least partially curable by means of high-energy radiation (see ) first exposure to infrared radiation (TR radiation) and then exposure to high-energy radiation, preferably ultraviolet radiation (UN radiation), the exposure to IR radiation Radiation can at least partially overlap the subsequent irradiation with high-energy radiation. "UV radiation, in particular, but also, for example, electron radiation can be used as high-energy radiation.
Bevorzugt wird nach Applikation des oder der mittels energiereicher Strahlung zumindest teilweise härtbaren Beschichtungsmittel(s) eine Ablüftphase gewährt. Es kann sich beispielsweise um ein Ablüften von 5 bis 15 Minuten, bevorzugt 5 bis 10 Minuten bei Raumtemperatur handeln. Erst anschließend erfolgt die Bestrahlung mit IR- Strahlung.After the application of the coating agent (s) which is at least partially curable by means of high-energy radiation, a flash-off phase is preferably granted. For example, it can be a venting of 5 to 15 minutes, preferably 5 to 10 minutes at room temperature. Irradiation is then carried out.
Die im erfindungsgemäßen Verfahren verwendeten mittels energiereicher Strahlung zumindest teilweise aushärtbaren Beschichtungsmittel können wäßrig, mit Lösemitteln verdünnt oder frei von Lösemitteln und Wasser sein. Es kann sich um mittels energiereicher Strahlung, bevorzugt mittels UV- Strahlung, vollständig oder nur teilweise aushärtbare Beschichtungsmittel handeln. Bei mittels energiereicher Strahlung aushärtbaren Beschichtungsmitteln handelt es sich insbesondere um dem Fachmann bekannte kationisch und/oder radikalisch härtende Beschichtungsmittel. Bevorzugt sind radikalisch härtende Beschichtungsmittel. Bei Einwirkung energiereicher Strahlung auf diese Beschichtungsmittel entstehen im Beschichtungsmittel Radikale, die eine Vernetzung durch radikalische Polymerisation olefinischer Doppelbindungen auslösen.The coating compositions which are at least partially curable by means of high-energy radiation in the process according to the invention can be aqueous, diluted with solvents or free from solvents and water. The coating compositions can be completely or only partially curable by means of high-energy radiation, preferably by means of UV radiation. Coating agents curable by means of high-energy radiation are, in particular, cationically and / or radically curing coating agents known to the person skilled in the art. Radically curing coating compositions are preferred. When high-energy radiation acts on these coating compositions, radicals are generated in the coating composition, which trigger crosslinking by radical polymerization of olefinic double bonds.
Die bevorzugt einsetzbaren radikalisch härtenden Beschichtungsmittel enthalten übliche Prepolymere, wie Poly- oder Oligomere, die radikalisch polymerisierbare olefinische Doppelbindungen, insbesondere in Form von (Meth)acryloylgruppen im Molekül aufweisen. Die Prepolymere können in Kombination mit üblichen Reaktiwerdünnern, d.h. reaktiven flüssigen Monomeren, vorliegen.The free-radically curing coating compositions which can be used preferably contain customary prepolymers, such as poly- or oligomers, which have free-radically polymerizable olefinic double bonds, in particular in the form of (meth) acryloyl groups in the molecule. The prepolymers can be used in combination with conventional reactive diluents, i.e. reactive liquid monomers.
Beispiele für Prepolymere oder Oligomere sind (meth)acrylfunktionelle (Meth)acrylcopolymere, Epoxidharz(meth)acrylate, Polyester(meth)acrylate, Polyether(meth)acrylate, Polyurethan(meth)acrylate, ungesättigte Polyester, ungesättigte Polyurethane oder Silikon(meth)acrylate mit zahlenmittleren Molekularmassen (Mn) bevorzugt im Bereich von 200 bis 10000, besonders bevorzugt von 500 bis 3000 und mit durchschnittlich 2 bis 20, bevorzugt 3 bis 10 radikalisch polymerisierbaren, olefinischen Doppelbindungen pro Molekül. Unter (Meth)acryl ist hier Acryl und/oder Methacryl zu verstehen. Werden Reaktivverdünner verwendet, so werden sie beispielsweise in Mengen von 1 bis 50 Gew.-%, bevorzugt von 5 bis 30 Gew.-%, bezogen auf das Gesamtgewicht von Prepolymeren und Reaktivverdünnern, eingesetzt. Es handelt sich um niedermolekulare definierte Verbindungen, die mono-, di- oder polyungesättigt sein können. Beispiele für solche Reaktivverdünner sind: (Meth)acrylsäure und deren Ester, Maleinsäure und deren Halbester, Vinylacetat, Vinylether, substituierte Vinylharnstoffe, Ethylen- und Propylenglykoldi(meth)acrylat, 1,3- und l,4-Butandioldi(meth)acrylat, Vinyl(meth)acrylat, Allyl(meth)acrylat, Giycerintri- , -di- und -mono(meth)acrylat, Trimethylolpropantri-, -di- und -mono(meth)acrylat, Styrol, Vinyltoluol, Divinylbenzol, Pentaerythrittri- und - tetra(meth)acrylat, Di- und Tripropylenglykoldi(meth)acrylat, Hexandioldi(meth)acrylat. Die Reaktiwerdünner können einzeln oder im Gemisch eingesetzt werden. Bevorzugt werden als Reaktiwerdünner Diacrylate wie z.B. Dipropylenglykoldiacrylat, Tripropylenglykoldiacrylat und/oder Hexandioldiacrylat eingesetzt.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, unsaturated polyesters, unsaturated polyurethanes or silicone (meth) acrylates with number average molecular masses (Mn) preferably in the range from 200 to 10,000, particularly preferably from 500 to 3000 and with an average of 2 to 20, preferably 3 to 10, radically polymerizable, olefinic double bonds per molecule. (Meth) acrylic here means acrylic and / or methacrylic. If reactive diluents are used, they are used, for example, in amounts of 1 to 50% by weight, preferably 5 to 30% by weight, based on the total weight of prepolymers and reactive diluents. These are defined low-molecular compounds that can be mono-, di- or polyunsaturated. Examples of such reactive diluents are: (meth) acrylic acid and its esters, maleic acid and its half esters, vinyl acetate, vinyl ether, substituted vinyl ureas, ethylene and propylene glycol di (meth) acrylate, 1,3- and 1,4-butanediol di (meth) acrylate, Vinyl (meth) acrylate, allyl (meth) acrylate, glycerol tri, di and mono (meth) acrylate, trimethylolpropane tri, di and mono (meth) acrylate, styrene, vinyl toluene, divinyl benzene, pentaerythritol tri and - tetra (meth) acrylate, di- and tripropylene glycol di (meth) acrylate, hexanediol di (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 thinners.
Die radikalisch härtenden Beschichtungsmittel enthalten Photoinitiatoren, z.B. in Mengen von 0,1 bis 5 Gew.-%, bevorzugt von 0,5 bis 3 Gew.-%, bezogen auf die Summe von radikalisch polymerisierbaren Prepolymeren, Reaktivverdünnern und Photoinitiatoren. Geeignet sind die üblichen Photoinitiatoren, wie beispielsweise Benzoin und -derivate, Acetophenon und -derivate, z.B. 2,2-Diacetoxyacetophenon, Benzophenon und -derivate, Thioxanthon und -derivate, Anthrachinon, 1-Benzoylcyclohexanol, phosphororganische Verbindungen, wie z.B. Acylphospinoxide. Die Photoinitiatoren können allein oder in Kombination eingesetzt werden. Außerdem können weitere synergistische Komponenten, z.B. tertiäre Amine, eingesetzt werden.The free radical curing coating compositions contain photoinitiators, e.g. in amounts of 0.1 to 5% by weight, preferably 0.5 to 3% by weight, based on the sum of free-radically polymerizable prepolymers, reactive diluents and photoinitiators. The usual photoinitiators, such as benzoin and derivatives, acetophenone and derivatives, e.g. 2,2-diacetoxyacetophenone, benzophenone and derivatives, thioxanthone and derivatives, anthraquinone, 1-benzoylcyclohexanol, organophosphorus compounds, e.g. Acylphosphine oxides. The photoinitiators can be used alone or in combination. In addition, other synergistic components, e.g. tertiary amines can be used.
Die im erfindungsgemäßen Verfahren einsetzbaren mittels energiereicher Strahlung zumindest teilweise härtbaren Beschichtungsmittel enthalten bevorzugt neben dem mittels energiereicher Strahlung härtbaren Bindemittelsystem ein oder mehrere weitere Bindemittel. Bei den weiteren Bindemitteln, die zusätzlich vorliegen können, handelt es sich bevorzugt um übliche mittels Additions- und/oder Kondensationsreaktionen aushärtbare Bindemittelsysteme. Es kann sich aber auch um übliche physikalisch trocknende Bindemittelsysteme oder um Kombinationen beider genannter Bindemittelsysteme handeln. Es ist auch möglich, daß das an sich mittels energiereicher Strahlung härtbare Bindemittelsystem zusätzlich zu den radikalisch polymerisierbaren Doppelbindungen zur Vernetzung durch Additions- und/oder Kondensationsreaktionen fähige Gruppen aufweist.The coating compositions which can be at least partially hardened by means of high-energy radiation in the process according to the invention preferably contain one or more further binders in addition to the binder system which is curable by means of high-energy radiation. The other binders, which may additionally be present, are preferably conventional binder systems which can be hardened by means of addition and / or condensation reactions. However, they can also be conventional physically drying binder systems or combinations of the two binder systems mentioned. It is also possible that this is by means of high energy Radiation-curable binder system in addition to the radically polymerizable double bonds for crosslinking by addition and / or condensation reactions has groups.
Bei den Additions- und/oder Kondensationsreaktionen im vorstehend genannten Sinne handelt es sich um dem Fachmann bekannte lackchemische Vernetzungsreaktionen wie beispielsweise die ringöffnende Addition einer Epoxidgruppe an eine Carboxylgruppe unter Bildung einer Ester- und einer Hydroxylgruppe, die Addition einer Hydroxylgruppe an eine Isocyanatgruppe unter Bildung einer Urethangruppe, die Reaktion einer Hydroxylgruppe mit einer blockierten Isocyanatgruppe unter Ausbildung einer Urethangruppe und Abspaltung des Blockierungsmittels, die Reaktion einer Hydroxylgruppe mit einer N-Methylolgruppe unter Wasserabspaltung, die Reaktion einer Hydroxylgruppe mit einer N-Methylolethergruppe unter Abspaltung des Veretherungsalkohols, die Umesterungsreaktion einer Hydroxylgruppe mit einer Estergruppe unter Abspaltung des Veresterungsalkohols, die Umurethamsierungsreaktion einer Hydroxylgruppe mit einer Carbamatgruppe unter Alkoholabspaltung, die Reaktion einer Carbamatgruppe mit einer N-Methylolethergruppe unter Abspaltung des Veretherungsalkohols .The addition and / or condensation reactions in the abovementioned sense are lacquer chemical crosslinking reactions known to the person skilled in the art, such as, for example, the ring-opening addition of an epoxy group to a carboxyl group to form an ester and a hydroxyl group, the addition of a hydroxyl group to an isocyanate group to form a Urethane group, the reaction of a hydroxyl group with a blocked isocyanate group to form a urethane group and elimination of the blocking agent, the reaction of a hydroxyl group with an N-methylol group with elimination of water, the reaction of a hydroxyl group with an N-methylol ether group with elimination of the etherification alcohol, the transesterification reaction of a hydroxyl group with an ester group with elimination of the esterification alcohol, the re-uramation reaction of a hydroxyl group with a carbamate group with alcohol elimination, the reaction of a carbamate group with an N-methylo lether group with elimination of the etherification alcohol.
Bevorzugt sind im Bindemittelsystem funktionelle Gruppen enthalten, die eine Vernetzung bei niedrigen Temperaturen, beipielsweise bei 20 bis 80 °C ermöglichen. Besonders bevorzugt kann es sich um Hydroxyl- und Isocyanatgruppen handeln. Die funktioneilen Gruppen, insbesondere die Hydroxylgruppen und Isocyanatgruppen können dabei jeweils im mittels energiereicher Strahlung härtbaren Bindemittel und/oder in einem separaten Bindemittel vorliegen.Functional groups are preferably contained in the binder system, which enable crosslinking at low temperatures, for example at 20 to 80 ° C. It can particularly preferably be hydroxyl and isocyanate groups. The functional groups, in particular the hydroxyl groups and isocyanate groups, can each be present in the binder curable by means of high-energy radiation and / or in a separate binder.
Bevorzugt können im Klarlack, Basislack oder Einschichtdecklack Polyurethan(meth)acrylate, Polyester(meth)acrylate und/oder (meth)acryloylfunktionelle Poly(meth)acrylate und im Füller oder weiteren Schichten, wie Zwischenschichten, bevorzugt Epoxid(meth)acrylate eingesetzt werden. Besonders gute Ergebnisse werden erhalten, wenn die vorstehend genannten (meth)acryloylfunktionellen Bindemittel mit Bindemitteln kombiniert werden, die auf einem Vernetzungsmechanismus zwischen Hydroxyl- und Isocyanatgruppen basieren. Die Hydroxyl- und/oder Isocyanatgruppen können dabei auch in dem oder den (meth)acryloylfunktionellen Bindemittel(n) vorhanden sein. Es ist nur zu beachten, daß die jeweiligen Komponenten mit Hydroxylgruppen und die jeweiligen Komponenten mit Isocyanatgruppen getrennt gelagert werden müssen und erst kurz vor der Applikation miteinander vermischt werden dürfen. Besonders bevorzugt und vorteilhaft einzusetzen sind Bindemittel Systeme, die (meth)acryloyl- und OH- funktionelle Komponenten und Polyisocyanate enthalten, wobei die (Metfriacryloyl- und OH-Gruppen in einer und/oder verschiedenen Bindemittelkomponenten enthalten sein können, und auch Bindemittelsysteme, enthaltend A) ein oder mehrere radikalisch polymerisierbare Doppelbindungen aufweisende Verbindungen, die zusätzlich mindestens eine weitere im Sinne einer Additions- und/oder Kondensationsreaktion reaktive funktionelle Gruppe enthalten und B) ein oder mehrere radikalisch polymerisierbare Doppelbindungen aufweisende Verbindungen, die zusätzlich mindestens eine weitere im Sinne einer Additions- und/oder Kondensationsreaktion reaktive funktionelle Gruppe enthalten, wobei die zusätzliche reaktive funktionelle Gruppe komplentär bzw. reaktiv ist gegenüber den zusätzlichen reaktiven funktioneilen Gruppen der Komponente A).Preferably, polyurethane (meth) acrylates, polyester (meth) acrylates and / or (meth) acryloyl-functional poly (meth) acrylates can be used in the clear coat, basecoat or single-layer topcoat and in the filler or other layers, such as intermediate layers, preferably epoxy (meth) acrylates. Particularly good results are obtained if the (meth) acryloyl-functional binders mentioned above are combined with binders which are based on a crosslinking mechanism between hydroxyl and isocyanate groups. The hydroxyl and / or isocyanate groups can also be present in the (meth) acryloyl-functional binder (s). It should only be noted that the respective components with hydroxyl groups and the respective components with isocyanate groups must be stored separately and may only be mixed with one another shortly before application. Binder systems which contain (meth) acryloyl and OH-functional components and polyisocyanates are particularly preferred and advantageously to be used, it being possible for the (metfriacryloyl and OH groups to be present in one and / or different binder components, and also binder systems comprising A ) one or more compounds which have free-radically polymerizable double bonds and which additionally contain at least one further functional group which is reactive in the sense of an addition and / or condensation reaction, and B) one or more compounds which have free-radical polymerizable double bonds which additionally contain at least one further in the sense of an addition and / or contain a condensation reaction reactive functional group, the additional reactive functional group being complementary or reactive towards the additional reactive functional groups of component A).
Gegebenenfalls können im letzteren Fall noch eine oder mehrere monomere, oligomere und/oder polymere Verbindung mit mindestens einer gegenüber den zusätzlich zu den radikalisch polymerisierbaren Doppelbindungen vorhandenen funktioneilen Gruppen aus Komponente A) oder Komponente B) im Sinne einer Additions- und/oder Kondensationsreaktion reaktiven funktioneilen Gruppe enthalten sein.In the latter case, one or more monomeric, oligomeric and / or polymeric compounds with at least one functional group from component A) or component B) which is present in addition to the radical-polymerizable double bonds can optionally also be reactive in the sense of an addition and / or condensation reaction Group.
Die im erfindungsgemäßen Verfahren einsetzbaren mittels energiereicher Strahlung zumindest teilweise härtbaren Beschichtungsmittel können zusätzliche, für die Lackformulierung übliche Komponenten enthalten. Sie können z.B. lackübliche Additive enthalten. Bei den Additiven handelt es sich um die üblichen auf dem Lacksektor einsetzbaren Additive. Beispiele für solche Additive sind Verlaufsmittel, Antikratermittel, Antischaummittel, Katalysatoren, Haftvermittler, rheologiebeeinflussende Additive, Verdicker, Lichtschutzmittel und Emulgatoren. Die Additive werden in üblichen, dem Fachmann geläufigen Mengen eingesetzt.The at least partially curable coating compositions which can be used in the process according to the invention can contain additional components which are customary for the coating formulation. You can e.g. customary paint additives included. The additives are the usual additives that can be used in the paint sector. Examples of such additives are leveling agents, anti-cratering agents, anti-foaming agents, catalysts, adhesion promoters, rheology-influencing additives, thickeners, light stabilizers and emulsifiers. The additives are used in customary amounts known to the person skilled in the art.
Die im erfindungsgemäßen Verfahren einsetzbaren Beschichtungsmittel können Anteile an organischen Lösemitteln und/oder Wasser enthalten. Bei den Lösemitteln handelt es sich um übliche lacktechnische Lösemittel. 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 und Amylacetat, 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.The coating compositions which can be used in the process according to the invention can contain proportions of organic solvents and / or water. The solvents are common paint solvents. These can come from the manufacture of the binders ' originate or are added separately. Examples of such solvents are monohydric or polyhydric alcohols, for example propanol, butanol, hexanol; Glycol ethers or esters, for example diethylene glycol dialkyl ether, dipropylene glycol dialkyl ether, in each case with C1 to C6 alkyl, ethoxypropanol, butyl glycol; Glycols, for example ethylene glycol, propylene glycol and their oligomers, esters, for example butyl acetate and amyl acetate, N-methylpyrrolidone and ketones, for example methyl ethyl ketone, acetone, cyclohexanone; aromatic or aliphatic hydrocarbons, for example toluene, xylene or linear or branched aliphatic C6-C12 hydrocarbons.
Die im erfindungsgemäßen Verfahren einsetzbaren Beschichtungsmittel können Pigmente und/oder Füllstoffe enthalten. Es handelt sich dabei um die üblichen in der Lackindustrie einsetzbaren Füllstoffe und organischen oder anorganischen färb- und/oder effektgebenden Pigmente und Korrosionsschutzpigmente. Beispiele für anorganische oder organische Farbpigmente sind Titandioxid, mikronisiertes Titandioxid, Eisenoxidpigmente, Ruß, Azopigmente, Phthalocyaninpigmente, Chinacridon- und Pyrrolopyrrolpigmente. Beispiele für Effektpigmente sind: Metallpigmente, z.B. aus Aluminium, Kupfer oder anderen Metallen; Interferenzpigmente, wie z.B. metalloxidbescbichtete Metallpigmente, z.B. titandioxidbeschichtetes oder ischoxidbeschichtetes Aluminium, beschichteter Glimmer, wie z.B. titandioxidbeschichteter Glimmer und Graphiteffektpigmente. Beispiele für Füllstoffe sind Siliciumdioxid, Aluminiumsilikat, Bariumsulfat und Talkum. In den Beschichtungsmitteln können vorteilhafterweise neben den üblichen Additiven spezielle gecoatete Füllstoffe zur Erhöhung der Kratzfestigkeit enthalten sein. Als Füllstoffe kommen hier z.B. micronisiertes Aluminiumoxid oder micronisierte Siliciumoxide in Frage. Diese Füllstoffe sind mit Verbindungen gecoatet, die UV-härtbare Gruppen enthalten, z.B. mit acrylfunktionellen Silanen, und werden somit bei der Strahlenhärtung des Beschichtungsmittels mit einbezogen. Derartige besonders für Klarlacke geeignete transparente Füllstoffe sind als Handelsprodukte, z.B. unter dem Namen AKTISIL® , erhältlich.The coating compositions which can be used in the process according to the invention can contain pigments and / or fillers. These are the usual fillers and organic or inorganic color and / or effect pigments and corrosion protection pigments that can be used in the paint industry. 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. Examples of effect pigments are: metal pigments, for example made of aluminum, copper or other metals; Interference pigments, such as metal oxide-coated metal pigments, for example titanium dioxide-coated or ischoxide-coated aluminum, coated mica, such as titanium dioxide-coated mica and graphite effect pigments. Examples of fillers are silicon dioxide, aluminum silicate, barium sulfate and talc. In addition to the usual additives, the coating compositions can advantageously contain special coated fillers to increase the scratch resistance. Fillers that can be used here are, for example, micronized aluminum oxide or micronized silicon oxides. These fillers are coated with compounds which contain UV-curable groups, for example with acrylic-functional silanes, and are therefore included in the radiation curing of the coating composition. Such suitable particularly for clearcoats transparent fillers are available as commercial products, for example under the name AKTISIL ® available.
Die generelle Zusammensetzung der einsetzbaren Beschichtungsmittel, beispielsweise die Art der Pigmentierung, richtet sich danach, welche Schicht des Mehrschichtaufbaus mit dem jeweiligen Beschichtungsmittel erstellt werden soll, d. h. ob es sich beispielsweise um einen Klarlack, einen Basislack oder einen Füller oder eine weitere übliche Zwischenschicht handelt.The general composition of the coating agents that can be used, for example the type of pigmentation, depends on which layer of the multilayer structure is to be created with the respective coating agent, ie whether it is, for example a clear coat, a basecoat or a filler or another common intermediate layer.
Der Auftrag der Beschichtungsmittel im erfindungsgemäßen Verfahren kann auf verschiedene Substrate erfolgen. Bevorzugte Substrate sind Metall- oderThe coating compositions can be applied to various substrates in the process according to the invention. Preferred substrates are metal or
Kunststoffsubstrate. Die Applikation im Mehrschichtaufbau erfolgt nach üblichen Verfahren, bevorzugt mittels Spritzauftrag. Die Substrate können vorbeschichtet, beispielsweise mit einer üblichen Grundierungsschicht versehen sein.Plastic substrates. The application in the multilayer structure is carried out by customary methods, preferably by spray application. The substrates can be precoated, for example provided with a customary primer layer.
Nach Applikation des oder der mittels energiereicher Strahlung zumindest teilweise härtbaren Beschichtungsmittel erfolgt die Bestrahlung mit TR-Strahlung. Es können dem Fachmann bekannte und für die Lacktrocknung übliche TR-Strahler eingesetzt werden. Der IR-Strahler wird vor der zu bestrahlenden Substratoberfläche, beispielsweise in einem Abstand von 20 bis 70 cm, positioniert. Die Bestrahlungsdauer mit TR-Strahlung kann beispielsweise 1 bis 20 min betragen. In Abhängigkeit von Bestrahlungsdauer undAfter application of the coating agent or agents at least partially curable by means of high-energy radiation, irradiation with TR radiation takes place. TR radiators which are known to the person skilled in the art and are customary for drying the paint can be used. The IR radiator is positioned in front of the substrate surface to be irradiated, for example at a distance of 20 to 70 cm. The radiation duration with TR radiation can be, for example, 1 to 20 minutes. Depending on the radiation duration and
Leistung der Strahlungsquelle können dabei an der Substratoberfläche Temperaturen von beispielsweise 40 bis 200°C erreicht werden. Günstigerweise sollten die Einstellungen so vorgenommen werden, daß Temperaturen von beispielsweise von 40 bis 100°C an der Substratoberfläche erreicht werden. Besonders gute Resultate werden erzielt, wenn nach der Applikation nicht direkt mit TR-Strahlung bestrahlt wird, sondern sich einePower of the radiation source, temperatures of, for example, 40 to 200 ° C. can be achieved on the substrate surface. Conveniently, the settings should be made so that temperatures of, for example, 40 to 100 ° C are reached on the substrate surface. Particularly good results are achieved if, after application, the radiation is not irradiated directly with TR radiation, but rather one
Ablüftphase anschließt. Es kann sich beispielsweise um ein Ablüften von 5 bis 15 Minuten, bevorzugt 5 bis 10 Minuten bei Raumtemperatur handeln.Flash-off phase follows. For example, it can be a venting of 5 to 15 minutes, preferably 5 to 10 minutes at room temperature.
Wenn mittels der IR-Bestrahlung die gewünschte Temperatur der Substratoberfläche erreicht bzw. die vorgesehene Bestrahlungsdauer abgelaufen ist, kann die Bestrahlung mit energiereicher Strahlung, bevorzugt mit UV- Strahlung erfolgen.When the desired temperature of the substrate surface has been reached by means of IR irradiation or the intended irradiation time has expired, the irradiation can be carried out with high-energy radiation, preferably with UV radiation.
Die Härtung der zumindest teilweise mittels energiereicher Strahlung, bevorzugt UV- Strahlung härtbaren Beschichtung kann bevorzugt mit UV- Strahlungsquellen mit Emissionen im Wellenlängenbereich von 180 bis 420 nm, insbesondere von 200 bis 400 nm erfolgen. 'Beipiele für einsetzbare UV-Strahlungsquellen sind z.B. Quecksilberhochdruck-, mitteldruck- und -niederdruckstrahier. Die Lampenlänge kann variieren. Gebräuchlich sind beispielsweise Lampen zwischen 5 und 200 cm Lampenlänge. In Abhängigkeit vom speziellen Anwendungsfall und von der benötigten Strahlungsenergie können Lampen- und Reflektorgeometrie in üblicher Weise aufeinander abgestimmt sein. Die jeweilige Lampenleistung kann beispielsweise zwischen 20 und 250 W/cm (Watt pro cm Lampenlänge) variieren. Bevorzugt werden Lampen mit Leistungen zwischen 80 und 120 W/cm eingesetzt. Gegebenenfalls können die Quecksilberlampen durch Einbringen von Metallhalogeniden auch dotiert sein. Beispiele dotierter Strahler sind Eisen- oder Galliumquecksilberlampen.The curing of the coating, which is curable at least partially by means of high-energy radiation, preferably UV radiation, can preferably be carried out with UV radiation sources with emissions in the wavelength range from 180 to 420 nm, in particular from 200 to 400 nm. ' Examples of UV radiation sources that can be used include high-pressure, medium-pressure and low-pressure mercury lamps. The lamp length can vary. For example, lamps between 5 and 200 cm in length are common. Depending on the specific application and the radiation energy required, the lamp and reflector geometry can be coordinated with one another in the usual way. The respective lamp power can vary, for example, between 20 and 250 W / cm (watts per cm lamp length). Lamps with powers between 80 and 120 W / cm are preferably used. If appropriate, the mercury lamps can also be doped by introducing metal halides. Examples of doped emitters are iron or gallium mercury lamps.
Weitere Beispiele für UV- Strahlungsquellen sind Gasentladungsröhren, wie z.B. Xenonniederdrucklampen, UV-Laser, UV-Punktstrahler, wie z.B. UV-emittierende Dioden und Schwarzlichtröhren. Neben diesen kontinuierlich arbeitenden UV- Strahlungsquellen können jedoch auch diskontinuierliche UV-Strahlungsquellen eingesetzt werden. Bevorzugt handelt es sich hierbei um sogenannte Hochenergieblitzeinrichtungen (kurz: UV-Blitzlampen). Die UV-Blitzlampen können eine Mehrzahl von Blitzröhren, beispielsweise mit inertem Gas, wie Xenon, gefüllte Quarzröhren, enthalten. Die UV- Blitzlampen weisen beispielsweise eine Beleuchtungsstärke von mindestens 10 Megalux, bevorzugt von 10 bis 80 Megalux pro Blitzentladung auf. Die Energie pro Blitzentladung kann beispielsweise 1 bis 10 kJoule betragen.Other examples of UV radiation sources are gas discharge tubes, e.g. Xenon low pressure lamps, UV lasers, UV spot lamps, e.g. UV emitting diodes and black light tubes. In addition to these continuously operating UV radiation sources, discontinuous UV radiation sources can also be used. These are preferably so-called high-energy flash devices (in short: UV flash lamps). The UV flash lamps can contain a plurality of flash tubes, for example quartz tubes filled with inert gas such as xenon. The UV flash lamps have, for example, an illuminance of at least 10 megalux, preferably from 10 to 80 megalux per flash discharge. The energy per flash discharge can be, for example, 1 to 10 kJoules.
Die UV- Strahlungsquellen sind im allgemeinen in eine UV- Anlage integriert, die normalerweise aus den UV- Strahlungsquellen, dem Reflektorsystem, der Stromversorgung, elektrischen Steuerungen, der Abschirmung, dem Kühlsystem und der Ozonabsaugung besteht. Andere Anordnungen sind natürlich auch möglich, ebenso können einzelne der genannten Bestandteile weggelassen werden.The UV radiation sources are generally integrated in a UV system, which normally consists of the UV radiation sources, the reflector system, the power supply, electrical controls, the shielding, the cooling system and the ozone extraction. Other arrangements are of course also possible, and individual components can also be omitted.
Die Betrahlungsdauer mit UV-Strahlung kann beim Einsatz von UV-Blitzlampen als UV- Strahlungsquelle beispielsweise im Bereich von 1 Millisekunde bis 400 Sekunden, bevorzugt von 4 bis 160 Sekunden, je nach Anzahl der gewählten Blitzentladungen, liegen. Die Blitze können beispielsweise etwa alle 4 Sekunden ausgelöst werden. Die Härtung kann beispielsweise durch. 1 bis 40 aufeinanderfolgende Blitzentladungen erfolgen.When using UV flash lamps as the UV radiation source, the exposure time to UV radiation can be, for example, in the range from 1 millisecond 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 Hardening can, for example, by. 1 to 40 successive lightning discharges.
Beim Einsatz kontinuierlicher UV- Strahlungsquellen kann die Bestrahlungsdauer beispielsweise im Bereich von einigen Sekunden bis etwa 5 Minuten, bevorzugt unter 5 Minuten liegen.When using continuous UV radiation sources, the irradiation time can range, for example, from a few seconds to about 5 minutes, preferably less than 5 minutes.
Der Abstand der UV- Strahlungsquellen zur zu bestrahlenden Substratoberfläche kann beispielsweise 5 bis 60 cm betragen. Die Abschirmung der UV- Strahlungsquellen zur Vermeidung von Strahlungsaustritt kann z.B. durch Verwendung eines entsprechend ausgekleideten Schutzgehäuses um eine transportable Lampeneinheit oder mit Hilfe anderer, dem Fachmann bekannter Sicherheitsmaßnahmen, erfolgen.The distance between the UV radiation sources and the substrate surface to be irradiated can be, for example, 5 to 60 cm. The shielding of the UV radiation sources to avoid radiation leakage can e.g. by using an appropriately lined protective housing around a transportable lamp unit or with the help of other safety measures known to the person skilled in the art.
Das erfindungsgemäße Verfahren zur Mehrschichtiackierung, welches dadurch gekennzeichnet ist, daß nach Applikation des oder der mittels energiereicher Strahlung zumindest teilweise härtbaren Beschichtungsmittel(s) zunächst eine Bestrahlung mit IR- Strahlung und anschließend eine Bestrahlung mit energiereicher Strahlung erfolgt, kann in verschiedenen Ausführungsformen durchgeführt werden.The process according to the invention for multi-layer painting, which is characterized in that after application of the coating agent (s) at least partially curable by means of high-energy radiation, radiation with IR radiation and then radiation with high-energy radiation is carried out in various embodiments.
So ist es beispielsweise möglich, die UV-Bestrahlungsphase an die beendete IR- Bestrahlungsphase anzuschließen oder die UV-Bestrahlung bei fortlaufender IR- Bestrahlung zu beginnen. Im letzteren Fall können IR- und UV-Bestrahlungsphase teilweise oder ganz überlappen, d.h. die IR-Bestrahlungsphase kann vor oder gleichzeitig mit Beendigung der UV-Bestrahlungsphase abgeschlossen werden.For example, it is possible to connect the UV radiation phase to the completed IR radiation phase or to start the UV radiation with continuous IR radiation. In the latter case, the IR and UV radiation phases can partially or completely overlap, i.e. the IR irradiation phase can be completed before or simultaneously with the termination of the UV irradiation phase.
Ebenso ist es möglich, an die abgeschlossene UV-Bestrahlungsphase eine weitere IR- Bestrahlungsphase anzuschließen. Die nachgeschaltete IR-Bestrahlungsphase kann beispielsweise 0,5 bis 30 Minuten betragen. Ansonsten gelten die vorstehend bereits gemachten Aussagen bezüglich der IR-Bestrahlung. Im Falle einer sich an die UV- Bestrahlungsphase anschließenden IR-Bestrahlungsphase können in Reihenfolge IR-, UV- und IR-Bestrahlung nacheinander durchgeführt werden oder die IR-Bestrahlungsphase erstreckt sich über die gesamte Bestrahlungszeit, d.h. die IR-Bestrahlung wird vor, während und auch nach der UV-Bestrahlungsphase durchgeführt. Die Bestrahlungsphasen IR-Bestrahlung und anschließende UV-Bestrahlung können je nach Bedarf auch mehrmals hintereinander wiederholt werden.It is also possible to connect a further IR radiation phase to the completed UV radiation phase. The subsequent IR radiation phase can be, for example, 0.5 to 30 minutes. Otherwise, the statements made above regarding IR radiation apply. In the case of an IR irradiation phase following the UV irradiation phase, IR, UV and IR irradiation can be carried out in sequence, or the IR irradiation phase extends over the entire irradiation time, ie the IR irradiation is carried out before, during and also carried out after the UV irradiation phase. The irradiation phases IR radiation and subsequent UV radiation can also be repeated several times as required.
Bei jeder der genannten Ausführungsformen können die Bestrahlungsdauer pro Bestrahlungsintervall und die Gesamtbestrahlungsdauer variiert werden.In each of the above-mentioned embodiments, the radiation duration per radiation interval and the total radiation duration can be varied.
Desweiteren ist es auch möglich die miteinander gekoppelten Bestrahlungsintervalle IR- und UV-Bestrahlung im Zusammenhang mit der Durchführung mehrerer Spritzgänge, mehrerer Arbeitsgänge oder im Zusammenhang mit der Strahlungshärtung mehrerer aufeinander folgender Schichten des Mehrschichtaufbaues anzuwenden.Furthermore, it is also possible to use the coupled radiation intervals IR and UV radiation in connection with the implementation of several spray coats, several work steps or in connection with the radiation curing of several successive layers of the multi-layer structure.
Beispielsweise kann nach Applikation des zumindest teilweise strahlungshärtbaren Beschichtungsmittels in einem Spritzgang zunächst eine Zwischenhärtung mit IR- Bestrahlung und eine anschließende UV-Bestrahlung erfolgen, nachfolgend wird das Beschichtungsmittel in einem oder mehreren weiteren Spritzgängen aufgebracht und es erfolgt wiederum zunächst eine IR- und anschließend eine UV-Bestrahlung. Diese Arbeitsweise ist beispielsweise bei der Applikation von in höheren Schichtdicken, z.B. bis 400 μm, gewünschten Füllerschichten besonders vorteilhaft.For example, after application of the at least partially radiation-curable coating agent, intermediate curing with IR irradiation and subsequent UV irradiation can take place in one spray pass, subsequently the coating agent is applied in one or more further spray passes and again IR and then UV Radiation. This method of operation is, for example, when applying thicker layers, e.g. up to 400 μm, desired filler layers are particularly advantageous.
Ebenso ist es möglich, im Mehrschichtaufbau zunächst einen zumindest teilweise strahlungshärtbaren Basislack zu applizieren und zunächst einer IR- und nachfolgend einer UV-Bestrahlung zu unterwerfen. Danach kann ein zumindest teilweise strahlungshärtbarer Klarlack appliziert und wieder zunächst einer IR- und nachfolgend einer UV-Bestrahlung unterworfen werden. Gegebenenfalls kann sich in beiden Fällen eine weitere TR- Bestrahlung an die UV-Bestrahlung anschließen. Die Strahlungshärtung der einzelnen Schichten des Mehrschichtaufbaues sowie der mittels mehrerer Spritzgänge aufgetragenen Schichten kann dabei jeweils mit unterschiedlicher Strahlungsintensität und unterschiedlicher Bestrahlungsdauer für jede Schicht einzeln oder für zwei oder mehrere Schichten gemeinsam erfolgen.It is also possible to first apply an at least partially radiation-curable basecoat in the multi-layer structure and first to subject it to IR and then UV radiation. An at least partially radiation-curable clear lacquer can then be applied and again subjected to IR and then UV radiation. If necessary, a further TR irradiation can follow the UV irradiation in both cases. The radiation curing of the individual layers of the multilayer structure and of the layers applied by means of a plurality of spray coats can each be carried out individually with different radiation intensities and with different irradiation times for each layer or together for two or more layers.
Zur erfindungsgemäßen Bestrahlung der lackierten Substratoberflächen ist es beispielsweise möglich, TR-Strahler und UV-Strahler nebeneinander zu positionieren und ' entsprechend zu schalten oder die Strahier gegebenenfalls wechselseitig vor der zu bestrahlenden Substratoberfläche zu positionieren. Es besteht auch die Möglichkeit einen sogenannten Kombi- Strahl er einzusetzen, der IR- und UV- Strahlungsquelle in einem Gerät beinhaltet. Beispielsweise können in letzterem Fall IR- und UV-Lampen in dem Gerät abwechselnd nebeneinander angeordnet sein.For the irradiation of the coated substrate surfaces according to the invention, it is possible, for example, to position TR emitters and UV emitters next to one another ' to switch accordingly or, if necessary, to position the beams alternately in front of the substrate surface to be irradiated. There is also the option of using a so-called combi beam that contains the IR and UV radiation source in one device. For example, in the latter case, IR and UV lamps can be arranged alternately side by side in the device.
Mit dem erfindungsgemäßen Verfahren können ein oder mehrere zumindest teilweise mittels energiereicher Strahlung aushärtbare Schichten eines üblichen Mehrschichtaufbaus in der Fahrzeuglackierung gehärtet werden. Dabei kann es sich beispielsweise um einen Mehrschichtaufbau aus Grundierung, Füller, Basislack und Klarlack oder ausWith the method according to the invention, one or more layers of a customary multi-layer structure, which can be at least partially hardened by means of high-energy radiation, can be hardened in the vehicle painting. This can be, for example, a multilayer structure consisting of primer, filler, basecoat and clearcoat
Grundierung, Füller und Einschichtdecklack handeln. Es können dabei ein oder mehrere Schichten des Mehrschichtaufbaus aus zumindest teilweise strahlungshärtbaren Beschichtungsmitteln erstellt werden.Act primer, filler and one-coat top coat. One or more layers of the multilayer structure can be created from at least partially radiation-curable coating agents.
Mit dem erfindungsgemäßen Verfahren werden rißbildungsfreie Beschichtungen mit sehr guter Haftung zum Untergrund und sehr guter Zwischenschichthaftung erhalten. Die applizierten Beschichtungen zeigen eine ausreichende Standfestigkeit und nach Härtung ein einwandfreies optisches Aussehen. Chemikalien-und Bewitterungsbeständigkeit sind sehr gut. Die erhaltenen Beschichtungen zeigen bei hoher Vernetzungsdichte gleichzeitig eine ausreichende Flexibilität. Mit dem erfindungsgemäßen Vefahren erstellte Füllerbeschichtungen sind sehr gut schleifbar.With the method according to the invention, crack-free coatings with very good adhesion to the substrate and very good interlayer adhesion are obtained. The applied coatings show sufficient stability and after curing have a perfect optical appearance. Chemical and weather resistance are very good. The coatings obtained also show sufficient flexibility with a high crosslinking density. Filler coatings created with the method according to the invention are very easy to sand.
Die Erfindung soll an Hand der folgenden Beispiele näher erläutert werden.The invention is illustrated by the following examples.
Beispiel 1example 1
Zunächst wurde ein mittels UV- Strahlung härtbarer Klarlack hergestellt. Dazu wurden folgende Komponenten miteinander vermischt und mittels Schnellrührer einige Minuten homogenisiert:First of all, a clear lacquer curable by means of UV radiation was produced. The following components were mixed together and homogenized for a few minutes using a high-speed stirrer:
55 g eines handelsüblichen OH- und acryloylfünktionellen Bindemittels (Jägalux 5154) 10 g eines handelsüblichen Polyisocyanates (Desmodur N 75)55 g of a commercially available OH and acryloyl functional binder (Jägalux 5154) 10 g of a commercially available polyisocyanate (Desmodur N 75)
3,8 g eines handelsüblichen Photoinitiators auf Basis Arylphosphinoxid (Lucirin TPO)3.8 g of a commercially available photoinitiator based on arylphosphine oxide (Lucirin TPO)
0,5 g eines handelsüblichen Verlaufsmittels (Byketol OK) " 2,5 g Butylacetat0.5 g of a standard leveling agent (Byketol OK) "2.5 g butyl acetate
Erstellung eines MehrschichtaufbausCreation of a multilayer structure
Auf ein durch kathodische Elektrotauchlackierung (KTL) beschichtetes Blech wurde eine Füllerschicht (Bindemittelbasis: 2K-Polyurethan, lösemittelbasierend) in einer resultierenden Trockenfilmschichtdicke von ca. 80 μm aufgebracht und nach kurzer Ablüftzeit bei Raumtemperatur 30 Minuten bei 60°C gehärtet.A filler layer (binder-based: 2-component polyurethane, solvent-based) was applied to a sheet coated by cathodic electrocoating (KTL) in a resulting dry film thickness of approx. 80 μm and cured at 60 ° C for 30 minutes after a short flash-off time at room temperature.
Auf die Füllerschicht wurde ein Wasserbasislack (hergestellt entsprechend DE-A-196 43 802 , Herstellungsbeispiel 4 ) in einer resultierenden Trockenfilmschichtdicke von 13 bis 15 μm appliziert. Nach einer Ablüftphase von 20 Minuten bei Raumtemperatur, wurde der wie vorstehend beschrieben hergestellte mittels UV- Strahlung härtbare Klarlack in einer resultierenden Trockenfilmschichtdicke von 40-50 μm appliziert.A water-based lacquer (produced in accordance with DE-A-196 43 802, production example 4) was applied to the filler layer in a resulting dry film layer thickness of 13 to 15 μm. After a flash-off phase of 20 minutes at room temperature, the UV-curable clearcoat produced as described above was applied in a resulting dry film layer thickness of 40-50 μm.
Nach einer Ablüftphase von 5 Minuten bei Raumtemperatur erfolgte eine IR-Bestrahlung des applizierten Klarlackes. Die Bestrahlungszeit betrug 5 Minuten. Anschließend erfolgte die UV-Bestrahlung mit einer UV-Blitzlampe (Leistung 3500 Ws). Die Bestrahlung erfolgte mit 30 Blitzen, die im Abstand von etwa 4 s ausgelöst wurden, bei einem Objektabstand von ca. 20 cm.After a flash-off phase of 5 minutes at room temperature, the applied clear lacquer was subjected to IR radiation. The irradiation time was 5 minutes. The UV radiation was then carried out using a UV flash lamp (power 3500 Ws). The irradiation was carried out with 30 flashes, which were triggered at intervals of approximately 4 s, at an object distance of approximately 20 cm.
Beipiel 2Example 2
Es wurde analog Beispiel 1 vorgegangen, nur mit dem Unterschied, daß an die UV- Bestrahlung eine weitere IR-Bestrahlung (5 Minuten Bestrahlungszeit) angeschlossen wurde.The procedure was analogous to Example 1, with the difference that a further IR irradiation (5 minutes irradiation time) was connected to the UV irradiation.
Vergieichsbeispiel 1Comparative Example 1
Es wurde analog Beispiel 1 vorgegangen mit dem Unterschied, daß nach Applikation des Klarlackes nach einer Ablüftphase von 30 Minuten bei Raumtemperatur direkt die UV- Bestrahlung mit einer UV-Blitzlampe (Leistung 3500 Ws) erfolgte. Die UV-Bestrahlung erfolgte mit 30 Blitzen, die im Abstand von ca. 4 s ausgelöst wurden, bei einem Objektabstand von ca. 20 cm. Vergleich der lacktechnischen ErgebnisseThe procedure was analogous to Example 1, with the difference that after application of the clear lacquer, after a flash-off phase of 30 minutes at room temperature, the UV radiation was carried out directly with a UV flash lamp (power 3500 Ws). The UV radiation was carried out with 30 flashes, which were triggered at intervals of approx. 4 s, at an object distance of approx. 20 cm. Comparison of the paint results
Figure imgf000017_0001
Figure imgf000017_0001
(1) Feucht/Warm-Test nach DIN 50017(1) Wet / warm test according to DIN 50017
(2) Beurteilung der Blasenbildung nach DIN 53209(2) Assessment of blistering according to DIN 53209
(3) Gitterschnitt in Anlehnung an DIN 53151 i.O. in Ordnung (3) Cross cut based on DIN 53151 OK okay

Claims

Patentansprüche: Claims:
1. Verfahren zur Mehrschichtiackierung durch Auftrag einer oder mehrerer Füllerund/oder weiterer Überzugsmittelschichten auf ein gegebenenfalls vorbeschichtetes Substrat und anschließend einer Decklackschicht aus einem Basislack/Klarlacl^ufbau oder aus einem pigmentierten Einschichtdecklack, wobei mindestens eine der Schichten des Mehrschichtaufbaus aus einem mittels energiereicher Strahlung zumindest teilweise härtbaren Beschichtungsmittel erstellt wird, dadurch gekennzeichnet, daß nach Applikation des oder der mittels energiereicher Strahlung zumindest teilweise härtbaren Beschichtungsmittel(s) zunächst eine Bestrahlung mit TR- Strahlung und anschließend eine Bestrahlung mit energiereicher Strahlung erfolgt, wobei die Bestrahlung mit IR- Strahlung die anschließende Bestrahlung mit energiereicher Strahlung zumindest teilweise überlappen kann.1.Method for multi-layer coating by applying one or more filler and / or further coating agent layers to an optionally precoated substrate and then a top coat layer from a basecoat / clear coat structure or from a pigmented single-layer topcoat, at least one of the layers of the multi-layer structure comprising at least one using high-energy radiation partially curable coating agent is created, characterized in that after application of the coating agent (s) at least partially curable by means of high-energy radiation, irradiation with TR radiation and then irradiation with high-energy radiation is carried out, the irradiation with IR radiation being followed by Irradiation with high-energy radiation can at least partially overlap.
2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß nach Applikation der mittels energiereicher Strahlung zumindest teilweise härtbaren Beschichtungsmittel eiine Ablüftphase bei Raumtemperatur durchgeführt wird, worauf die Bestrahlung mit der IR- Strahlung erfolgt.2. The method according to claim 1, characterized in that after application of the coating agent at least partially curable by means of high-energy radiation, a flash-off phase is carried out at room temperature, whereupon the irradiation with the IR radiation takes place.
3. Verfahren nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß als zumindest teilweise durch energiereiche Strahlung härtbare Schicht eine Füller Schicht, eine pigmentierte Decklackschicht, eine Basislackschicht und/oder eine Klarlackschicht appliziert wird. 3. The method according to claim 1 or 2, characterized in that a filler layer, a pigmented top coat layer, a basecoat layer and / or a clear coat layer is applied as at least partially curable layer by high-energy radiation.
4. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß die mittels energiereicher Strahlung härtbaren Beschichtungsmittel zusätzlich mittels Additions- und/oder Kondensationsreaktionen aushärtbare Bindemittelsysteme enthalten. 4. The method according to any one of the preceding claims, characterized in that the coating compositions curable by means of high-energy radiation additionally contain curable binder systems by means of addition and / or condensation reactions.
5. Verfahren nach Anspruch 4, dadurch gekennzeichnet, daß es sich bei den zusätzlich enthaltenen Bindemittelsystemen um solche auf der Basis von OH-funktionellen und5. The method according to claim 4, characterized in that the binder systems additionally contained are those based on OH-functional and
NCO-funktionellen Bindemittelkomponenten handelt. NCO-functional binder components.
6. Verfahren nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß die durch energiereiche Strahlung härtbaren Beschichtungsmittel (meτh)acryloylfunktionelle Bindemittel enthalten, die zusätzlich reaktive funktionelle Gruppen aufweisen.6. The method according to any one of claims 1 to 3, characterized in that the coating agents curable by high-energy radiation (meτh) contain acryloyl-functional binders which additionally have reactive functional groups.
7. Verfahren nach Anspruch 6, dadurch gekennzeichnet, daß es sich bei den zusätzlichen funktionellen Gruppen um OH- und/oder NCO-Gruppen handelt.7. The method according to claim 6, characterized in that the additional functional groups are OH and / or NCO groups.
8. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß anschließend an die Bestrahlung mit energiereicher Strahlung noch eine TR-Bestrahlung durchgeführt wird.8. The method according to any one of the preceding claims, characterized in that a TR irradiation is carried out subsequent to the irradiation with high-energy radiation.
9. Verfahren nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß es zur Reparaturlackierung, insbesondere von Fahrzeugen durchgeführt wird. 9. The method according to any one of the preceding claims, characterized in that it is carried out for refinishing, in particular vehicles.
PCT/EP1999/009064 1998-12-16 1999-11-24 Method for multi-layer varnishing WO2000035598A1 (en)

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Application Number Priority Date Filing Date Title
DK99962155T DK1152841T3 (en) 1998-12-16 1999-11-24 Process for multilayer coating
EP99962155A EP1152841B2 (en) 1998-12-16 1999-11-24 Method for multi-layer varnishing
CA002347868A CA2347868C (en) 1998-12-16 1999-11-24 Multilayer lacquer coating process
JP2000587898A JP2002532234A (en) 1998-12-16 1999-11-24 Multi-layer lacquer coating method
AT99962155T ATE219392T1 (en) 1998-12-16 1999-11-24 MULTI-LAYER PAINT PROCESS
DE59901829T DE59901829D1 (en) 1998-12-16 1999-11-24 MULTI-LAYER PAINTING METHOD

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DE19857941.1 1998-12-16
DE19857941A DE19857941C2 (en) 1998-12-16 1998-12-16 Process for multi-layer painting

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US6528126B1 (en) 1998-12-16 2003-03-04 E. I. Du Pont De Nemours And Company Method for multi-layer varnishing with radiation hardenable coating agents
JP2003093967A (en) * 2001-09-25 2003-04-02 Kansai Paint Co Ltd Repair painting method
EP2222762B1 (en) 2007-12-20 2019-03-27 Coatings Foreign IP Co. LLC Process for producing a multilayer coating

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JP6540178B2 (en) * 2015-04-13 2019-07-10 コニカミノルタ株式会社 Method of manufacturing electrophotographic photosensitive member
PL233241B1 (en) * 2017-09-06 2019-09-30 Politech Spolka Z Ograniczona Odpowiedzialnoscia Method for decoration of cosmetic package elements, made from plastics

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JP2003093967A (en) * 2001-09-25 2003-04-02 Kansai Paint Co Ltd Repair painting method
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ES2176040T3 (en) 2002-11-16
DK1152841T3 (en) 2002-07-29
EP1152841B2 (en) 2008-02-13
ES2176040T5 (en) 2008-07-01
JP2002532234A (en) 2002-10-02
DE19857941A1 (en) 2000-06-21
PT1152841E (en) 2002-11-29
EP1152841A1 (en) 2001-11-14
EP1152841B1 (en) 2002-06-19
DE19857941C2 (en) 2002-08-29
CA2347868C (en) 2009-07-14
CA2347868A1 (en) 2000-06-22
ATE219392T1 (en) 2002-07-15

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