Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
  • B05D7/50—Multilayers
  • B05D7/52—Two layers
  • B05D7/53—Base coat plus clear coat type
  • B05D7/532—Base coat plus clear coat type the two layers being cured or baked together, i.e. wet on wet
• • 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
  • 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

Definitions

• the invention relates to a method for Mel rtiklacktechnik of substrates using Tahlungshärbare Beschichnrngsmi tel.
• the method can advantageously be used in vehicle and industrial painting, preferably in vehicle repair painting.
• UV technology has long been state of the art in coating and hardening.
• coating compositions curable by means of high-energy radiation 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.
• the use of heat-curable binders or coating agents can combine UV radiation with thermal treatment.
• the warming or ernischen treatment can be realized for example by means of hot air, heating plate or infrared radiation (IR radiation).
• the coating can be dried with IR radiation before the UV irradiation and thus different properties, such as the interlayer coating, weather resistance and optics can be improved in this way radiation-curing lacquer required flash-off times can be reduced.
• the flash-off phase is considerably shortened.
• a subsequent LR radiation is advantageous, for example, if the coating contains, in addition to the radiation-curable binders, further binders which crosslink via an additional mechanism. In such a case, complete curing can be achieved quickly with the subsequent IR radiation.
• a combination of UV and IR radiation during the curing process in the broader sense can be realized, for example, by continuously moving the UV radiation source or LR radiation source and / or the object to be irradiated past one another or by discontinuously UV radiation source and IR radiation source are placed alternately in front of the object to be irradiated.
• a disadvantage of the described procedures is that, on the one hand, at least two drying or hardening zones (UV zone and LR zone) to be passed through are present in the continuous process and UV and IR zones must be separated from one another, for example by glare protection, and on the other hand in the discontinuous mode of operation, UV and IR radiation sources, depending on the number of desired radiation intervals in front of the object to be irradiated, have to be exchanged mutually, the UV lamp generally not being operated during the IR drying phase.
• Radiation sources especially UV lamps, generally have a time-delaying effect on the entire painting process. Especially when using the discontinuous procedure e.g. In paint shops, the vehicle throughput and thus ultimately the profitability of the workshop can be impaired.
• the object of the invention was therefore to provide a process for multi-layer coating using at least partially curable coating compositions, which enables UV radiation and IR radiation to be combined in a simple, economical and time-saving manner without curing an undesirably high level equipment and thus costly effort to have to operate.
• the object is achieved by the method for forming an object of the invention Multi-layer coating by applying one or more fillers and / or further coating agent layers to an optionally pre-coated substrate and then from a top coat layer from a basecoat / clear coat structure or from a pigmented single-layer top coat, wherein at least one of the layers of the multi-layer structure is produced from a coating agent which is at least partially curable by means of high-energy radiation and this layer (s) are irradiated with UV radiation and IR radiation, which is characterized in that a UV radiation source is used for the irradiation with UV and IR radiation, which has an LR radiation component in its emission spectrum and that by alternating upstream of a UV filter and an IR filter and / or alternately upstream and omitting a UV filter or an IR filter in front of the UV radiation source, at least two radiation intervals are formed, during which different m it is irradiated with UV radiation, IR radiation or simultaneously with UV radiation and IR radiation.
• UV filters and IR filters When working according to the invention, it is possible to use UV filters and IR filters alternately. It is also possible to work with either a UV filter or an IR filter and alternately omit it so that UV and IR radiation are irradiated simultaneously. Both working methods can be combined with one another, so that alternating radiation intervals with UV radiation, IR radiation or together UV and IR radiation are formed.
• UV radiation sources that can be used in the method according to the invention and modified with an upstream filter can thus be used quickly and easily as pure LR radiators.
• UV radiation sources can be used as the UV radiation source, provided that they have an LR radiation component in their emission spectrum.
• Such UV radiation sources are known to the person skilled in the art and are generally accessible.
• the IR radiation component required in the emission spectrum of the UV radiation source is preferably a radiation component in the region of the short-wave IR radiation. This is the wavelength range from about 700 to about 2500 nm.
• UV radiation sources that can be used according to the invention are preferably from 800 to 2000 nm, for example, have an emission spectrum, including UV and LR emission components, in the range from 180 to 2500 nm, preferably from 200 to 2500 nm, particularly preferably from 200 to 2000 nm
• the UV radiation sources used in practice and known to the person skilled in the art generally have a UV radiation component in the emission spectrum of approximately 25%.
• a considerable LR radiation component in the emission spectrum can be, for example, up to approximately 60%.
• UV radiation sources which can be used well in the process according to the invention are, for example, high-pressure, medium-pressure and low-pressure mercury lamps. Lamps of between 5 and 200 cm in length are used. Depending on the specific application and the required radiation energy, the lamp and reflector geometry are matched to one another in the usual way. The respective lamp output can vary, for example, between 20 and 250 W / cm (watt per cm lamp length). cm used.
• the mercury lamps may also be doped by introducing metal halides. Examples of doped emitters are iron or gallium mercury lamps
• UV radiation sources are gas discharge tubes, such as xenon low-pressure lamps.
• discontinuous UV radiation sources can also be used. These are preferably so-called high-energy flash devices (short UV flash lamps).
• the UV flash lamps can have a plurality of flash tubes, for example quartz tubes filled with inert gas such as xenon. contain.
• the UV flash lamps for example, have 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 which can be used in the method according to the invention are modified by connecting a UV or IR filter upstream of the UV radiation source.
• a UV filter is to be understood as a filter which essentially does not contain any radiation in the Wavelength range of UV radiation, ie in particular in the range of about 180 to 380 nm, transmits, but is transparent to IR radiation.
• An IR filter is to be understood as a filter which essentially does not transmit any radiation in the wavelength range of the IR radiation, in particular in the range from about 700 to 2500 nm, but is transparent to UV radiation.
• the wavelength portion of the visible light can be completely or partially filtered out or passed through, depending on the choice of the corresponding filter
• conventional UV and / or IR filters can be used to modify the UV radiation source. They are known to the person skilled in the art and are commercially available.
• the filters can, for example, be foils, e.g. LR transmission foils, or glass filters with different transmission curves.
• the filters are available in different sizes, shapes and different thicknesses.
• the glass filter types GG e.g. GG 474 from Schott can be used. So-called LR transmission foils can also be used.
• the glass filter types FG e.g. FG 3, or BG, e.g. BG 26, BG 3, from Schott.
• the UV radiation sources that can be used in the method according to the invention can be equipped with the respective filter in any manner.
• 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 it is also possible to use only parts of the components of a UV system mentioned here.
• the process according to the invention for multi-layer coating can be carried out using the UV radiation sources which can be modified with a filter be carried out in different ways.
• Irradiation intervals with UV radiation, LR radiation or UV and LR radiation can be combined with one another as desired.
• the number and sequence of the respective irradiation intervals, the irradiation duration per irradiation interval and the total irradiation duration can be varied.
• the viewing agent which is at least partially curable by means of high-energy radiation
• Application is carried out in the usual way, for example by means of spray application.
• a drying phase or heating phase with LR radiation follows after a possibly allowed flash-off phase.
• the drying phase is intended to accelerate the flashing off, that is to say that the action of heat means that the organic solvents still present in the coating and / or in the case of water-based lacquers of the water are evaporated off in a relatively short time.
• the heating of the substrate surface achieved with the LR radiation also has a positive effect on the curing process by means of UV radiation, since a higher level in the case of binder systems curable by means of UV radiation
• Crosslinking density can be achieved if the crosslinking is started in the heat.
• the LR radiation is realized by, as already described above, a UV filter connected upstream of the UV radiation source used and irradiated accordingly. During this irradiation interval, the
• the irradiation time with LR radiation can be, for example, 1 to 20 min. If a UV flash lamp is used as the UV radiation source, the LR irradiation can also be carried out by triggering several flash discharges. The irradiation time depends, for example, on the type and amount of the solvents still present in the coating after application. Depending on the radiation duration and power of the radiation source, temperatures of, for example, 40 to 200 ° C. can be reached on the substrate surface. The settings should preferably be made so that temperatures of, for example, from 40 to 100 ° C can be reached on the substrate surface. When the desired temperature of the substrate surface has been reached or the intended exposure time has expired, the UV filter is removed. After removing the UV filter, UV crosslinking begins immediately in the case of continuously operating radiation sources. In the case of discontinuously operated UV flash lamps, the desired UV flashes are triggered after the UV filter has been removed.
• 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 curing can be carried out, 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 coupling of an LR radiation phase with a subsequent UV radiation phase using the UV radiation sources which can be used in the method according to the invention with an upstream UV filter offers, inter alia, the advantage that the stoving phase of a continuous UV radiation source is used for predrying or heating the substrate surface can. If, in addition to the binders curable by means of UV radiation, there are also binders in the coating agent which crosslink or harden according to an additional mechanism, there is the further advantage that a certain degree of crosslinking already takes place as a result of the LR radiation, which leads to improved stability, for example leads.
• the curing process with radiation intervals UV radiation and subsequent LR radiation is to be explained below.
• the coating agent which is at least partially curable by means of high-energy radiation is applied.
• the application can be carried out in the usual way, for example by means of spray application.
• the irradiation phase with UV radiation follows.
• the implementation of UV radiation corresponds to the statements already made above.
• the irradiation phase with LR radiation follows.
• the LR radiation is realized by, as already described above, a UV filter connected upstream of the UV radiation source used and irradiated accordingly.
• the subsequent LR irradiation phase can be, for example, 0.5 to 30 minutes. Otherwise, the statements made above regarding LR radiation apply.
• the coupling of a UV irradiation phase with a subsequent LR irradiation phase can be particularly advantageous if, in addition to the radiation-curable binders, the applied coating agent also contains other binders which crosslink via an additional mechanism and / or are physically drying. In these cases, the final LR drying phase quickly leads to the complete curing of the applied coating.
• any further combinations of UV, LR or UV and LR irradiation are of course possible.
• Other possible examples of combinations are: LR-BesttaMung-W-BesttaMung-IR-Bestta ⁇ ung; U irradiation-LR irradiation.
• the coating agent is subjected to LR irradiation and subsequent UV irradiation in one spraying step, subsequently the coating agent is applied in one or more further spraying steps, and again an LR and then UV radiation.
• one or more layers of a conventional multi-layer structure can be hardened in vehicle painting.
• This can be, for example, a mixed-coat structure consisting of primer, filler, basecoat, clearcoat or of primer, filler, one-coat topcoat.
• One or more layers of the multilayer structure can be created from at least partially radiation-curable coating agents.
• the coating agents which are at least partially curable by means of high-energy radiation in the process according to the invention are not subject to any restrictions; they can be aqueous, diluted with solvents or free from solvents and water. It can be fully or only partially curable by means of high-energy radiation, preferably by means of UV radiation. Visiting agents that can be cured by means of high-energy radiation are, in particular, cationic and / or free-radically curing agents known to the person skilled in the art. Radically curing coating compositions are preferred. When high-energy radiation acts on these coating agents, radicals are generated in the coating agent, 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 in combination with conventional reactive diluents, ie reactive liquid monomers.
• prepolymers or oligomers are (me) acrylic-functional (meth) acrylic copolymers, epoxy resin (meth) acrylates, polyester (meth) acrylates,
• Mn moderate average molecular weights
• (Meth) acrylic means mer 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.
• 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 all defined molecular compounds that can be mono-, di- or polyunsaturated. Examples of such
• Reactive thinners are: vIeth) 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) acrylic StyroL, vinyl toluene, divinylbenzene, pentaerythritol tri and
• the reactive diluents can be used individually or in a mixture.
• Preferred reactive diluents are diacrylates such as e.g. Dipropylene glycol diacrylate, tripropylene glycol diacrylate and / or hexanediol diacrylate are used.
• the free radical curing agents 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, TMoxanthone and
• acylphosphine oxides such as acylphosphine oxides.
• the photoinitiators can be used alone or in combination.
• other synergistic components for example tertiary amines, can be used become.
• the at least partially curable curatives that can be used in the process according to the invention can contain one or more other binders in addition to the binder system curable by high-energy radiation.
• the additional binders which may additionally be present can be, for example, customary binder systems curable by means of addition and / or condensation reactions and / or customary physically drying binder systems. It is also possible that the binder system, which is curable per se by means of high-energy radiation, has, in addition to the free-radically polymerizable double bonds, crosslinking by addition and / or condensation reactions.
• lacquer crosslinking reactions known to those skilled in the art, such as the ring-opening addition of an epoxy group to a carboxyl group to form an ester and a hydroxyl group, and the addition of a hydroxyl group to an isocyanate group to form one 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 UmurethaMs mecanicsreaction of a hydroxyl group with a carbamate group with alcohol elimination, the reaction of a carbamate group with an N-methylol ether group with elimination of the the
• the coating agents which can be used in the process according to the invention and are at least partially curable by means of high-energy radiation can contain additional components which are customary for the coating formulation.
• they can contain additives that are customary in paint.
• the additives are the usual additives that can be used in the paint sector. Examples of such additives are distribution agents, anti-adhesive agents, anti-foaming agents, catalysts, Adhesion promoter, rheology-influencing additives, thickeners, light stabilizers and emulsifiers.
• the additives are used in customary amounts known to the person skilled in the art.
• the spraying agents which can be used in the process according to the invention can contain small amounts of organic solvents and / or water.
• the solvents are conventional lacquer-technical solvents. These can originate from the production of the binders or are added separately.
• Examples of such solvents are monohydric or polyhydric alcohols, e.g. Propanol, butanol, hexanol; Glycol ethers or esters, e.g. Diethylene glycol dialkyl ether, dipropylene glycol dialkyl ether, each with Cl to C6 alkyl, ethoxypropanol, butyl glycol; Glycols, e.g. Ethylene glycol, propylene glycol and their
• Oligomers e.g. Butyl acetate and amyl acetate, N-methylpyrrolidone and ketones, e.g. Methyl ethyl ketone, acetone, cyclohexanone; aromatic or aliphatic hydrocarbons, e.g. Toluene, xylene or linear or branched aliphatic C6-C12 hydrocarbons.
• esters e.g. Butyl acetate and amyl acetate
• ketones e.g. Methyl ethyl ketone, acetone, cyclohexanone
• aromatic or aliphatic hydrocarbons e.g. Toluene, xylene or linear or branched aliphatic C6-C12 hydrocarbons.
• the spraying agents 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 anti-corrosion pigments that can be used in the paint industry. Examples of inorganic or organic color pigments are titanium dioxide, microsized titanium dioxide, iron oxide pigments, and carbon black.
• Azo pigments, phthalocyanine pigments, quinacridone and pyrrolopyrrole pigments are: metal pigments, e.g. made of AlumiMu, copper or other metals; interference pigments, e.g. metal oxide coated metal pigments, e.g. titanium dioxide coated or mixed oxide coated aluminum, coated mica, e.g. Titanium dioxide coated mica and graphite effect pigments.
• metal pigments e.g. made of AlumiMu, copper or other metals
• interference pigments e.g. metal oxide coated metal pigments, e.g. titanium dioxide coated or mixed oxide coated aluminum
• coated mica e.g. Titanium dioxide coated mica and graphite effect pigments.
• fillers are silicon dioxide, aluminum silicate, barium sulfate and talc.
• the general composition of the usable lubricants depends on which bad of the me- dium structure is to be created with the lubricants.
• the advantages of a combined UV / IR curing can be exploited in a simple manner without great expenditure on equipment and costs become.
• my radiation intervals with LR or UV radiation can alternate. It is not necessary to position more sources of radiation, which would be ineffective, particularly when repairing smaller damaged areas.
• the method according to the invention enables more economical work, in particular in a painting workshop, for example for refinishing.
• the invention is illustrated by the following example.
• a water-based lacquer (produced in accordance with DE-A-196 43 802, production example 4) was applied to filler-coated KTL sheet metal in a resulting dry film thickness of approximately 15 ⁇ m. IR irradiation then took place.
• a UV flash lamp power 3500 Ws, approx. 50% LR radiation component in the emission spectrum
• an attachable UV filter glass filter GG 475 from Schott, size: 50 x 50 mm 2 , thickness: 2 mm.
• 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.
• the UV-curable clearcoat produced as described above was applied in a resulting dry film thickness of about 50 ⁇ m.
• the applied clear lacquer was subjected to IR radiation.
• the above was modified with the UV filter UV flash lamp used. Irradiation was carried out with 20 flashes, which were triggered at intervals of approx. 4 s, at an object distance of approximately 20 cm. The UV irradiation then took place.
• the UV filter was removed from the UV flash lamp and an IR filter (glass filter FG 3 from Schott, size: 50 x 50 mm 2 , thickness: 2 mm) was attached. Irradiation was carried out with 20 flashes, which were triggered at intervals of approx. 4 s, at an object distance of approximately 20 cm.

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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)

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• 1998
  • 1998-12-16 DE DE19857940A patent/DE19857940C1/de not_active Expired - Fee Related
• 1999
  • 1999-11-24 AT AT99958117T patent/ATE246966T1/de not_active IP Right Cessation
  • 1999-11-24 WO PCT/EP1999/009062 patent/WO2000035597A1/fr active IP Right Grant
  • 1999-11-24 EP EP99958117A patent/EP1060029B1/fr not_active Expired - Lifetime
  • 1999-11-24 DE DE59906592T patent/DE59906592D1/de not_active Expired - Fee Related
  • 1999-11-24 JP JP2000587897A patent/JP2002532233A/ja active Pending
  • 1999-11-24 US US09/622,389 patent/US6528126B1/en not_active Expired - Fee Related
  • 1999-11-24 CA CA002320314A patent/CA2320314A1/fr not_active Abandoned
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