JP2015512331A - Method and apparatus for producing cured coating film - Google Patents

Abstract

The subject of the present invention is a portable spray gun that can initiate radiation curing without the need to protect the operator from radiation. This spray gun is a needle that can be used to seal the feed channel 2 for the radiation curable coating composition and the outlet 13 of the feed channel 2 that can move longitudinally and form an annular gap around itself. 1 and the needle 1 is designed to transmit electromagnetic radiation that can be used to initiate curing of the at least one radiation curable coating composition and / or the supply line Reference numeral 12 is designed to transmit electromagnetic radiation, and an illumination device 10 is mounted on the supply line 12.

Description

  The present invention relates to a method and apparatus for producing a cured coating on a substrate surface.

  Conventional spray guns usually allow coating material to be carried from the reservoir into the spray gun, where the coating material travels along the needle through a channel in the shape of an annular gap, It is sprinkled by a nozzle formed by the needle tip and casing by a flow of gas, inert gas, or compressed air (called jet air). It is possible to widen the shape of the spray cone, for example by sending further gas to the nozzle by so-called horn air. A paint spraying method using airless atomization is also known. In this method, in contrast to air atomization, the coating composition is atomized only by the pressure of the material. For this purpose, the coating composition or coating material is pressurized by passing through the nozzle holes and becomes a spray jet. Usually, with a spray gun, the coating material is simply applied to the substrate. Then, following the application, it is cured in a separate process, for example, by baking the coating material or by radiation curing.

  US313233 describes a method of applying a coating material to a large substrate such as the body of an automobile. In that method, the coating material is activated before application to the substrate.

  The disadvantage is that the device is stationary and cannot be easily miniaturized.

  JP 61-098740, JP 07-227567, EP 393407, and JP 2007-083166 describe the general possibility of exposing the coating material before passing through a spray gun, It does not disclose details about what the exposure is and the location of the exposure.

  DE 19961990 describes a method of forming a part by pre-pressing a material to be cured into a mold and starting curing.

  DE 3702999 describes the curing of UV (ultraviolet) reactive resin materials. The material passes through the channel exposed by the light guide from the outside (FIG. 1 of the publication) or from the back (FIG. 2 of the publication). A resin material is used for adhesion (adhesion). Under the conditions described, the UV-reactive resin material can be cured only because of the relatively long residence time in the exposure apparatus. As a result of the low exposure intensity of commercially available equipment, the achievable volume flow is low.

  The disadvantage of the latter case is that UV light may penetrate outside along the channel. This can result in additional cost and complexity for UV protection measures and can result in undesirable cured deposits at the channel edges. Further, in each of the explicitly disclosed examples, exposure times of 5 seconds and 10 seconds are disclosed. Thus, the disclosed system (consisting of exposure apparatus and coating material) is unsuitable for a spray gun. Furthermore, it is not envisaged to spray the adhesive resin material by spraying, nor is it possible in view of the high viscosity of such a resin material.

  EP 1002587A discloses the exposure of a radiation curable coating material in a spray gun and thus the curing of the applied coating material during application to a substrate, or the initiation of curing.

  The disadvantage of the solution presented there is that the spray gun has to be modified by mounting a light guide at the outlet opening of the nozzle in an expensive and inconvenient operation.

  Known from EP 159299 is to modify a commercially available spray gun to have an extension directed onto the substrate, ie in the same direction as the spray jet. In this way, an external exposure of the spray jet and / or the coated substrate can be performed, and thus curing can be performed or initiated.

  The disadvantage is that the coating operator must be protected from ultraviolet radiation as a result of external exposure. Furthermore, the spray gun becomes difficult to handle as a result of the irradiation device being mounted on the injection port. Furthermore, extensive UV irradiation of the drop mist is expensive and inconvenient, and the substrate irradiation is not uniform.

SUMMARY OF THE INVENTION AND MODE FOR CARRYING OUT THE INVENTION

  Therefore, an object of the present invention is to develop a portable spray gun that can be used to initiate radiation curing without the need to protect the operator from radiation. Commercially available spray guns can be easily modified in simple form.

The object could be achieved by the following spray gun. That is,
At least one, preferably one, supply channel 2 for at least one, preferably one radiation curable coating composition;
At least one, preferably one optional supply channel 3 for the gas;
A needle 1 that can be used to seal the outlet 13 of the at least one supply channel 2 that can move longitudinally and forms an annular gap around it,
The at least one optional supply channel 3 for the gas and the at least one supply channel 2 include the at least one radiation curable coating composition that has passed from the at least one supply channel 2 through the outlet 13. Provided to be atomized by gas from the at least one optional supply channel 3, or in the absence of the optional supply channel 3, by physical force;
Furthermore, the reservoir 11 for the at least one coating composition has a supply line 12 from the reservoir 11 to the supply channel 2;
The needle 1 is designed to transmit electromagnetic radiation that can be used to initiate curing of the at least one radiation curable coating composition, and / or
The portable spray gun is characterized in that the supply line 12 is designed to transmit electromagnetic radiation, and the illumination device 10 is mounted on the supply line 12.

  In one embodiment, the electromagnetic radiation is introduced into the spray gun through the needle 1 of the present invention.

  An advantage of the present invention is that the needle 1 of the present invention is transparent to electromagnetic radiation through the existing needles of commercially available spray guns which are commercially available, i.e. commercially available spray guns, which are usually made of metal. By replacing it, it can be easily modified.

  The needle 1 of the present invention capable of transmitting electromagnetic radiation is preferably manufactured to have the same diameter and the same tip structure (shape, etc.) as the original conventional needle. If desired, the tip structure can be slightly changed, for example, by changing the cone angle or incorporating one or more shoulders or grooves in the tip.

  In other respects, the dimensions of the needle 1 and the needle tip are based on the original needle. The diameter of the needle (shown as e in FIG. 1) is preferably 0.5-10 mm, more preferably 2-5 mm. In some cases, smaller diameters are possible.

  It is essential for the present invention that the needle 1 is made of a material that is transparent to electromagnetic radiation in the wavelength range necessary to initiate curing in the at least one radiation curable coating material. is there.

  This type of transmissive material is, for example, quartz, polymethylmethacrylate (Plexiglas®) or other transparent plastics, for example polycarbonate (PC), polyethylene (PE), polypropylene (PP), sapphire glass , Calcite, glass, hollow body having an input surface and an output surface, and a preferred material is quartz. When UV light is used, there should be significant (substantial) transparency (transparency) for the wavelength region below 450 nm.

  In general and preferably, it is sufficient that only the surface of the tip of the needle 1 (indicated by 6 in FIG. 1) is designed to transmit electromagnetic radiation. Accordingly, in the spray gun of the present invention, the portion f in FIG. 1 is exposed (irradiated) and can be used for activation of the photoinitiator in the at least one coating composition.

  The length of the part f is preferably 1 to 30 mm, more preferably 2 to 20 mm, and very preferably 4 to 15 mm.

  In a preferred embodiment of the invention, the surface 7 of the supply channel 2 facing the surface 6 in the exposed portion f is reflective to the radiation used. The effect of this is that electromagnetic radiation can be used more efficiently.

  The main body of the needle 1 is transparent (that is, has transparency) to the radiation to be used, and acts as a radiation guide. Therefore, if the outer surface of the cylindrical portion of the needle 1 represented by reference numeral 5 in FIG. 1 also transmits electromagnetic waves, there is no additional advantage. This is usually accompanied by drawbacks. This is because areas of very little flow of material are exposed and harden inside the spray gun.

  On the back side, the needle 1 is connected to a lighting device (not shown in FIG. 1). This illumination device emits electromagnetic radiation in at least a desired wavelength region into the radiation guide of the needle 1.

  The illumination device may be mounted directly on the needle 1, but is preferably connected to the needle 1, more preferably connected to the needle 1 by a light guide.

  Examples of suitable lighting devices are low pressure mercury lamps, intermediate pressure mercury lamps or high pressure mercury lamps, fluorescent tubes, pulsed emitters, metal halide lamps, excimer emitters, light emitting diodes (LEDs), laser diodes, and other laser systems. Radiation curing is carried out by irradiating with high energy radiation, in other words IR (infrared), NIR (near infrared), UV radiation, daylight (sunlight), preferably UV radiation (ultraviolet).

  The desired wavelength region λ emitted from the illumination device must include the wavelength region for performing radiation curing. This wavelength region should preferably also include the absorption spectrum, particularly preferably the activation spectrum, of at least one photoinitiator I used in the coating composition (see below). For example, the desired wavelength region includes 200-2500 nm, preferably 200-2000 nm, more preferably 200-1500 nm, very preferably 200-1000 nm, more specifically 200-780 nm, especially 340-500 nm.

The dose of radiation introduced should be in the range of 80-30000 mJ / cm ^{2 in} the case of UV curing.

  In a preferred embodiment of the invention, the lighting device comprises one or more LEDs that emit in the UV region, more preferably LEDs or LED systems that emit UV light in the wavelength region of 365-450 nm. When using two or more LEDs, for example 2 to 100, preferably 2 to 50, more preferably 3 to 25, very preferably 3 to 16 LEDs, the illumination diameter of the illumination device is set to the needle 1 You may need to adapt to the diameter of. This can be achieved preferably by an adapter device or a converging lens.

  A special advantage of LEDs is that, thanks to their small physical size, they can be mounted directly on the needle or on the body of the spray gun and do not need to be connected to the needle 1 via a light guide. .

  The needle 1 is configured to be movable in the longitudinal direction, so that its movement causes at least one supply channel 2 for at least one coating composition to the outlet 13 having a diameter d. Can thus be closed and thus the spraying (spraying) of the coating composition can be adjusted or prevented. It will be appreciated that in order to close the outlet 13, the diameter e must be greater than d, especially in the region of the outlet 13.

  The supply channel 2 is usually provided in the form of an annular gap around the needle 1, but its arrangement of the supply channel 2 is not essential (essential) for the present invention, other arrangements are conceivable, in which case If there is, it will have the same effect.

  The width of the supply channel 2 between the needle 1 and the wall 4 (represented by a in FIG. 1) can be 0.05-5 mm, preferably 0.1-1.5 mm, more preferably 0.00. 1 to 1 mm.

  Optionally, at least one spray gas is supplied via the at least one further supply channel 3 on the side of the outlet 13 remote from the needle 1. The effect of this spray gas is to atomize the at least one coating composition.

  As an option, it is possible to provide the spray gun of the present invention with an outlet for so-called horn air in the injection direction. This additional outlet allows the resulting spray cone to be shaped to create a specific spray pattern after exiting the nozzle 14.

  Further, as an option, it is possible to give the spray gun an airless configuration. That is, there is no need for a supply channel 3 for spray gas and the coating composition is atomized or atomized without sending gas. Instead of sending the gas, the liquid coating composition in the supply channel 2 is vigorously rotated and atomized as it exits the outlet 13.

  However, in a preferred embodiment, there is at least one supply channel 3 through which the spray gas is supplied.

  The supply channel 3 is usually arranged in the form of an annular gap around the jet of at least one coating composition emerging from the outlet 13, but this arrangement of the supply channel 3 is not essential to the invention. Other arrangements of the supply channel 3 are also conceivable and can have an equivalent effect.

  The width of the supply channel 3 is represented by b in FIG. 1 and can be 0.1-5 mm, preferably 0.2-4 mm, more preferably 0.3-3 mm.

  The at least one gas supplied through the supply channel 3 is preferably air, but it is also conceivable to use a different gas, for example an inert gas such as nitrogen or carbon dioxide.

  At least one gas supplied through the supply channel 3 is supplied via a line from a reservoir external to the spray gun to the supply channel 3, preferably in a compressed manner. The at least one gas is usually sent into the spray gun with a superatmospheric pressure of up to 5 bar, preferably up to 3 bar, more preferably 2 bar.

  The two supply channels 2 and 3 are separated from each other by a wall 4.

  The design of the nozzle 14 having the width c is not essential (essential) for the present invention. The decisive factor is the effect from the point of view of atomizing the at least one coating composition so that the coating composition can be applied to the substrate in the desired manner.

  In a further embodiment of the invention, the coating composition is exposed in the portion between the reservoir 11 and the spray gun outlet. This may be done in addition to or in lieu of the embodiment in which electromagnetic radiation is introduced into the spray gun through the needle 1 of the present invention. It is preferred to expose the coating composition in the area between the reservoir 11 and the spray gun outlet (exit).

  At least one radiation curable coating composition supplied via the supply channel 2 may be supplied via a line from a reservoir external to the spray gun into the supply channel 2 or directly connected to the spray gun. May be supplied via the reservoir 11. In both cases, the supply line 12 from the external reservoir or reservoir 11 to the supply channel 2 is made transparent to electromagnetic radiation over the part h, so that further electromagnetic radiation is transmitted via the illumination device 10 to the at least one coating composition. It can be introduced into things.

  The illumination device 10 that performs exposure from one side of the supply line 12, exposure from both sides of the supply line 12, or exposure in an annular arrangement surrounding the supply line 12, for example, as a flat connection member between the reservoir tank and the spray gun itself Can be installed in between. This connecting member can be molded or injection molded from a transparent polymer, for example, and can be designed to be replaceable due to baking of the coating composition, alteration or deterioration of the transparent material. Such connecting members can have various diameters i. This is because the penetration depth of electromagnetic radiation into the radiation curable coating composition is sufficient to initiate curing, depending on the different photoinitiators and the different concentrations and / or different volume flow rates of the photoinitiator. This is to achieve a proper penetration depth.

  The size of the illumination area of the illuminating device may vary, and therefore a different number of light sources, eg LEDs, can be mounted. There may be a plurality of lighting devices arranged in a circle around the supply line 12. If reservoir 11 is not directly attached to the spray gun and the coating composition is supplied from a further reservoir facility, the supply line may be illuminated and take the form of a hose. Another embodiment comprises a hose as the supply line 12, which comprises a plurality of replaceable, preferably parallel, transparent windows, preferably made of transparent injection molded plastic, LEDs are attached to these windows. With this configuration, when a window is attached, the window can be easily replaced and the LED can be reused.

  Accordingly, the supply line 12 has a length of several millimeters to several meters, and the illuminated portion h covers a part of the entire length of the supply line 12 to the entire length thereof.

  This allows for various residence times at practical volume flow rates. Furthermore, the static mixer housed in the illuminated part can homogenize the residence time of the coating composition near the one-sided zone where the exposure intensity is higher, and the unexposed volume element can be jetted and subsequently coated. It can be prevented that non-crosslinked regions of the material are generated.

  The illumination device 10 preferably emits light having the same wavelength region as the electromagnetic radiation supplied via the needle 1. However, it is also conceivable to irradiate in different wavelength regions. However, in that case, the condition is that the at least one coating composition contains a photoinitiator I that can be activated in the different wavelength regions.

  In the spray gun of the present invention, the two embodiments of the present invention (exposure through the needle 1 and / or exposure between the reservoir 11 and the spray gun) may be used together or separately. It can also be used. Preference is given to exposing between the reservoir 11 and the spray gun and optionally supplementing with exposure through the needle 1.

  In order to increase the dose of electromagnetic radiation, optionally, at least one further illumination device 8 is arranged to irradiate the supply channel 2 from outside to inside. For this purpose, the wall 4 in the region of the illumination device 8 is provided with a transparent window 9 of length g that transmits electromagnetic radiation emitted by the illumination device 8 in a wavelength region suitable for the photoinitiator. It is necessary.

  When the penetration depth of the curing radiation is reduced, the channel shape for the coating material can be wide and thin. For this purpose, the supply channel 2 is divided into thin individual channels, each of which is illuminated. Further, the channel 2 may be provided with a thin layer structure.

  Preferably, the illumination device 8 emits light in the same wavelength region as the electromagnetic radiation supplied via the needle 1. However, it is also conceivable to irradiate in different wavelength regions. However, in that case, the condition is that the at least one coating composition contains a photoinitiator I that can be activated in the different wavelength regions.

  Said at least one coating composition (e.g. 1 to 3, preferably 1 or 2, more preferably only 1 coating composition) can be cured by electromagnetic radiation or at least initiates curing Of a kind that can

  Here, “curing” means polymerization of a low molecular weight component in the coating composition, and a high molecular weight compound is produced. This polymerization is preferably radical polymerization or polycondensation.

  In one preferred embodiment of the invention, the coating composition comprises at least one photoinitiator that can be activated by irradiated electromagnetic radiation to form activated ethylenically unsaturated double bonds and radicals that initiate radical polymerization. Of the kind provided with I.

  The activated ethylenically unsaturated double bond is preferably selected from the group consisting of acrylate groups, methacrylate groups and vinyl ether groups, more preferably from the group consisting of acrylate groups and methacrylate groups.

  An advantageous coating composition is of the type described in WO 2005/119208 A1, page 5, line 7 to page 7, line 21 (corresponding to paragraphs [0033] to [0046] of US2008 / 0032037A1). , Expressly incorporated herein by reference.

  The photoinitiator I present for the activation of the coating composition can be activated, for example, by UV radiation, IR radiation and / or MIR radiation and / or by daylight, preferably by UV radiation.

  Such photoinitiators that can be activated by UV radiation are known, for example, from WO 2005/119208 A1, page 7, line 23 to page 9, line 10 (corresponding to paragraphs [0047] to [0059] of US2008 / 0032037A1). Which is expressly incorporated by reference and is part of this disclosure.

  This type of photoinitiator that can be activated by NIR or IR radiation is, for example, WO 2005 / 085372A1, page 3, line 24 to page 5, line 18 (corresponding to paragraphs [0013] to [0023] of US2007 / 277700A1) Which is expressly incorporated by reference and is part of this disclosure.

  One photoinitiator can be used in the coating composition, or two or more photoinitiators can be used in combination. The latter is particularly preferred when electromagnetic radiation is input in different wavelength regions via the needle 1 and optional illumination devices 8 and / 10 in the device according to the invention.

  For example, a UV active photoinitiator and a NIR active photoinitiator may be used in combination. Alternatively, two UV active photoinitiators may be used as long as they are activated in sufficiently different wavelength regions.

  In a particularly preferred embodiment of the invention, the coating composition comprises a two-component polyurethane coating composition, and their polycondensation is initiated by a Lewis acid that is released upon irradiation with electromagnetic radiation.

  Said two-component polyurethane coating composition is preferably a coating composition comprising at least one polyisocyanate and at least one binder.

  Said polyisocyanate preferably comprises an aliphatic or cycloaliphatic polyisocyanate having at least two NCO functional groups, which is generally from 5% to 25% by weight, calculated as NCO = 42 g / mol. Has an NCO content.

  Examples of the binder include polyacrylate polyol, polyester polyol, polyether polyol, polyurethane polyol; polyurea polyol; polyester polyacrylate polyol; polyester polyurethane polyol; polyurethane polyacrylate polyol, polyurethane-modified alkyd resin; fatty acid-modified polyester polyurethane polyol, allyl Copolymers with ethers, graft polymers of the aforementioned compounds (for example having different glass transition temperatures), and mixtures of the aforementioned binders. Preference is given to polyacrylate polyols, polyester polyols and polyurethane polyols.

  Preferred OH values measured according to DIN 53240-2 (by potentiometric method) are 40 to 350 mg KOH / g, preferably 80 to 180 mg KOH / g for polyester, 15 to 250 mg KOH / g for polyacrylate-ol, preferably Is 80-160 mg KOH / g.

  The binder may also have an acid value of up to 200 mg KOH / g, preferably up to 150 mg KOH / g, more preferably up to 100 mg KOH / g, according to DIN EN ISO 3682 (potentiometric method). Good.

  Particularly preferred binders are polyacrylate polyols and polyesterols.

  These types of coating compositions are described, for example, in WO2009 / 050115A1, page 30, line 22 to page 33, line 20, which is expressly incorporated herein by reference.

Lewis acids released by electromagnetic radiation are, for example, WO2009 / 050115A1, page 2, line 4 to page 28, line 34, WO2011 / 032837A1, page 1, line 35 to page 18, line 9, WO2011 / 032875A1, page 1 42. From line 14 to page 14, line 4, each of which is expressly incorporated herein by reference.

  Suitable in the present invention is photo-induced polymerization with a long dark reaction (eg, a two-component reaction or a cationic reaction for the coating composition to be colored).

  “Long” here means the time before the viscosity of the coating composition suddenly increases (the result of this rapid increase is that the coating composition is no longer treated with a spray gun), preferably the spray gun It means that the residence time of the coating composition in the inside, that is, the time from the exposure to the exit of the nozzle 14 is 10 times.

  In this case, the layer thickness of the coating composition at the location of the illumination device 6, 8 and / or 10 during exposure is preferably selected to be less than 1 mm, more preferably less than 100 μm, very preferably less than 10 μm. preferable.

  A single Lewis acid may be used as the photoinitiator I in the coating composition, or two or more Lewis acids may be used as the photoinitiator. The latter is particularly preferred when electromagnetic radiation is input in different wavelength regions via the needle 1 and optional illumination devices 8 and / or 10 in the device of the invention.

  For example, a UV active photoinitiator and a NIR active photoinitiator may be used in combination. Alternatively, two UV active photoinitiators may be used as long as they are activated in sufficiently different wavelength regions.

  Furthermore, typical coating additives in coating compositions include, for example, antioxidants, antioxidants, stabilizers, activators (accelerators), dyes, degassers, brighteners, antistatic agents, difficult Flame retardants, thickeners, thixotropic agents, flow control agents, binders, antifoaming agents, fragrances, surfactants, viscosity modifiers, plasticizers, softeners, tackifier resins (tackifiers) tackifiers, chelates It is possible to add an agent or a compatibilizing agent (compatibilizing agent).

  Colored coating compositions may be used. This is particularly possible when the pigment is at least partially transparent to the irradiated electromagnetic length region that activates the photoinitiator I. This is common for photoinitiators I that can be activated in the IR or NIR region. However, even a colored coating composition that absorbs radiation in this wavelength region can be activated in the spray gun if the quantum yield of the photoinitiator in the spray gun of the present invention is sufficiently high. This can be further supported by providing a static mixer. Static mixers increase the layer thickness that can be exposed by spinning the coating composition around in the exposed area.

  It must be ensured that the coating composition to be applied has a viscosity that can be applied by a spray gun. This coating viscosity can be obtained by mixing in a solvent until the desired viscosity is reached.

  Generally speaking, the viscosity of the radiation curable coating composition is 10 to 10000 mPas, preferably 10 to 1000 mPas at 25 ° C.

  The advantage of the present invention is that, as a result of the exposure in the spray gun, no electromagnetic radiation goes out, only a small if any, and instead the radiation is almost completely contained in the spray gun. Because it is absorbed, there is no need to protect the workplace from UV radiation for painters.

  The dose of electromagnetic radiation introduced into the coating composition can be increased by adjusting the surface so that the surface opposite the illumination device is reflective.

  The lighting devices 8 and 10 preferably include a housing 15 so that electromagnetic radiation cannot penetrate (transmit) to the outside. The present invention represents an advance over the prior art. This is because, in the spray gun of the present invention, exposure occurs only in the short portions f, g, h, and the coating composition is only exposed to electromagnetic radiation for much less than 1 second in that portion. First, it is now possible to initiate polycondensation in a two-component polyurethane coating composition with the last mentioned Lewis acid. If the long connecting member 10 is used between a reservoir 11 and a spray gun with a number of light sources such as LEDs, the residence time can be in the second range. This is surprising as long as the prior art DE 3702999 explicitly discloses exposure times of 5 and 10 seconds for the initiation of the polymerization. Compared to this long exposure time known from the prior art, with a short exposure time as in the apparatus of the present invention, it is possible that the radiation is fully contained in the coating composition to initiate curing of the coating composition. It ’s amazing.

  Thus, in a preferred combination of the invention, the portable spray gun described above is used to apply a two-component polyurethane coating composition to a substrate. The polycondensation of the two-component polyurethane coating composition is then initiated by the Lewis acid released upon exposure to electromagnetic radiation.

  The present invention further provides a method of applying a coating composition to a substrate with a spray gun. The spray gun is a spray gun according to the present invention, and the coating composition is a type of coating composition that can be cured by electromagnetic radiation, or at least can initiate curing, A two-component polyurethane coating composition in which polycondensation is initiated by a Lewis acid released upon exposure to electromagnetic radiation.

  The present invention further provides the use of a spray gun according to the present invention for applying such a coating composition to a substrate. Curing of the coating composition can be performed by electromagnetic radiation, or at least initiated, and the coating composition is preferably polycondensed by a Lewis acid released by exposure to electromagnetic radiation. A two-component polyurethane coating composition that is initiated.

  The method of the present invention can be applied to wood, plywood, paper, cardboard, woven fabric, membrane, foil, leather, non-woven fabric, plastic surface, glass, ceramic, mineral building materials such as molded cement block, fiber cement slab, or metal, etc. Suitable for coating substrates. Each of these may be pre-coated and / or pre-treated as an option, preferably for wood, plastic, metal, more preferably for plastic and metal.

  The present invention is particularly applicable to automobiles, (large) vehicles, aircraft, industrial applications, agricultural and construction utility vehicles, decorative coatings, bridges, buildings, transmission towers, tanks, containers, pipelines, power plants, chemical plants. Suitable for coatings for ships, cranes, piles, seat piles, valves, pipes, fittings, flanges, couplings, halls, roofs, structural steel, furniture, windows, doors, flooring, especially preferred Automotive, (large) vehicles, aircraft, multi-purpose vehicle coatings, very preferably automotive coatings, especially for repair applications.

1 Needle 2 Supply channel for at least one coating composition 3 Supply channel for at least one gas (optional)
4 Wall 5 The outer surface 6 of the needle 1 The surface 7 at the tip of the needle 1 The surface 8 of the wall 4 facing the surface 6 Further illumination device (optional)
9 Wall 4 window (optional)
10 further illumination device 11 reservoir 12 supply line 13 outlet 14 nozzle 15 illumination device housing a width of supply channel 2 b width of supply channel 3 c width of nozzle 14 d width of outlet 13 e diameter of needle 1 f of exposed part 6 Length g Length of exposed portion 9 h Length of exposed portion 12 Diameter of supply line 12

Claims (11)

At least one, preferably one, supply channel 2 for at least one, preferably one radiation curable coating composition;
At least one, preferably one optional supply channel 3 for the gas;
A needle 1 that can be used to seal the outlet 13 of the at least one supply channel 2 that can move longitudinally and forms an annular gap around it,
The at least one optional supply channel 3 for the gas and the at least one supply channel 2 include the at least one radiation curable coating composition that has passed from the at least one supply channel 2 through the outlet 13. Provided to be atomized by gas from the at least one optional supply channel 3, or in the absence of the optional supply channel 3, by physical force;
Furthermore, the reservoir 11 for the at least one coating composition has a supply line 12 from the reservoir 11 to the supply channel 2;
The needle 1 is designed to transmit electromagnetic radiation that can be used to initiate curing of the at least one radiation curable coating composition, and / or
The portable spray gun is characterized in that the supply line 12 is designed to transmit electromagnetic radiation, and the illumination device 10 is mounted on the supply line 12.   The apparatus according to claim 1, wherein the needle is made of a material selected from the group consisting of quartz, polymethylmethacrylate, sapphire glass, and calcite.   The device according to claim 1 or 2, wherein the surface (7) facing the surface (6) of the needle (1) is reflective.   The device according to claim 1, wherein at least one UV-emitting LED or at least one LED system is mounted directly on the needle 1.   Furthermore, at least one further lighting device 8 is mounted to emit electromagnetic radiation from outside to inside through the window 9 into the supply channel 2, the window 9 being located in the region of the lighting device 8. The device according to claim 1, wherein the device has transparency to the wavelength region.   6. The supply line 12 according to any one of the preceding claims, wherein the supply line 12 has a diameter i that allows a penetration depth of electromagnetic radiation into the radiation curable coating composition to be sufficient to initiate curing. The apparatus according to 1.   7. A device according to any one of the preceding claims, characterized in that the supply line (12) is replaceable and is at least partially made of transparent plastic. A method of applying a coating composition to a substrate with a spray gun,
The spray gun according to any one of claims 1 to 7, wherein the coating composition can be cured by electromagnetic radiation, or at least can start curing. A method characterized by being an object.   The coating composition is of the type comprising an activated ethylenically unsaturated double bond and at least one photoinitiator I that can be activated by irradiated electromagnetic radiation to form radicals that initiate radical polymerization. The method according to claim 8, wherein:   9. The method of claim 8, wherein the coating composition is a two-component polyurethane coating composition in which polycondensation is initiated by a Lewis acid released upon exposure to electromagnetic radiation.   Use of a spray gun according to any one of claims 1 to 7 for applying a coating composition to a substrate, wherein the curing of the coating composition can be carried out by electromagnetic radiation, or Usage characterized by being able to start at least.

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