EP1791652B1 - Device and process for curing using energy-rich radiation in an inert gas atmosphere - Google Patents

Abstract

The invention relates to an apparatus and a method of producing molding materials and coatings on substrates by curing radiation-curable materials under an inert gas atmosphere by exposure to high-energy radiation.

Description

The invention relates to a device and a method for producing molding compositions and coatings on substrates by curing radiation-curable compositions under an inert gas atmosphere by irradiation with high-energy radiation.

In the radiation curing of radically polymerizable compounds, e.g. Of (meth) acrylate compounds or vinyl ether compounds, a strong inhibition of polymerization or curing by oxygen may occur. This inhibition results in incomplete surface hardening, e.g. to sticky coatings.

This oxygen inhibition effect can be achieved by the use of high amounts of photoinitiator, by co-using coinitiators, for. Amines, high energy, high dose UV radiation, e.g. be reduced with high pressure mercury lamps or by the addition of barrier-forming waxes.

It is also known to carry out the radiation curing under an inert protective gas, for example EP-A-540 884 , from Joachim Jung, RadTech Europe 99, Berlin 08. to 10.11.1999 in Berlin (UV-Applications in Europe Yesterday-Today Tomorrow).

Radiation curable compositions may include both volatile diluents, such as water or organic solvents, and processed in the absence of such diluents. The process of radiation curing is suitable for coatings, which are carried out in industrial applications or in medium or small crafts or in the domestic sector. So far, however, the complex implementation of the method and the devices required for this purpose, in particular the UV lamps, an application of radiation curing in the non-industrial areas prevented.

WO 01/39897 describes a method for radiation curing under an inert gas atmosphere that is heavier than air, preferably carbon dioxide. A preferred embodiment for curing described therein takes place in a dip tank.

There is a need to improve the method disclosed therein by further reducing protective gas losses and the contamination by atmospheric oxygen, which occur, for example, when the protective gas atmosphere is heated, for example because of the waste heat. Desired is a greater independence of heat sources in the irradiation room and thus to achieve more freedom with the choice of type, positioning and number of irradiation options.

In RadTech Conference Proceedings, November 3 - 5, 2003, Berlin, Germany, Dr. Ing. E-rich Beck, BASF AG, Germany; "UV Curing under Carbon Dioxide", p. 855-863; Volume II, ISBN 3-87870-152-7 , A method and a device for radiation curing under CO _{2 are} presented, which allows a continuous process for curing under inert gas. The disadvantage of this is that the consumption of inert gas is still relatively high.

The object of the invention was to provide a device with which a radiation curing can be performed and you can keep the consumption of inert gas as low as possible.

• seitliche Abdeckungen 2, 3, 4 und 5,
• obere und untere Abdeckungen 6 und 7, wobei 2, 3, 4, 5, 6 und 7 gemeinsam einen Innenraum umschließen,
• eine oder mehrere Trennwände 8, die den Innenraum unterteilen, wobei die Trennwände 8 mit der unteren Abdeckung 7 abschließen und einen Abstand d1 zur oberen Abdeckung 6 freilassen,
• eine oder mehrere Trennwände 9, die den Innenraum unterteilen, wobei die Trennwände 9 mit der oberen Abdeckung 6 abschließen und einen Abstand d2 zur unteren Abdeckung 7 freilassen,
• wobei 8 und 9 mit der jeweils benachbarten Trennwand 9 oder 8 und gegebenenfalls den seitlichen Abdeckungen 2 oder 3 einen unterteilten Innenraum (Kompartiment) bilden,
• mindestens eine innerhalb des Innenraums und/oder in den Innenraum hinein strahlende Strahlungsquelle 10,
• mindestens eine Gaszuführungsvorrichtung 11, mit der ein Gas oder Gasgemisch in den Innenraum geführt oder dort gebildet werden kann,
• mindestens eine Fördervorrichtung 12 für das Substrat S,
• Einlaß 13 und
• Auslaß 14,
• Wobei
• die Trennwände 8 im wesentlichen senkrecht auf die untere Abdeckung 7 stehen,
• die Trennwände 9 im wesentlichen senkrecht auf die obere Abdeckung 6 stehen,
• die Abstände d1 und d2 sowie die Breite b der Vorrichtung 1 so gewählt sind, daß sie größer sind als die Dimensionen des Substrats S entlang der Förderrichtung der Fördervorrichtung 12 und
• durch die Vorrichtungen 2, 3, 8 und 9 mindestens 4 Kompartimente ausgebildet werden.

The object has been achieved by a device 1 for carrying out a curing of coatings on a substrate S under an inert gas atmosphere containing

• side covers 2, 3, 4 and 5,
• upper and lower covers 6 and 7, wherein 2, 3, 4, 5, 6 and 7 together enclose an inner space,
• one or more partitions 8 that divide the interior, the partitions 8 being flush with the bottom cover 7 and leaving a distance d1 from the top cover 6 ,
• one or more partition walls 9 dividing the interior space, the partition walls 9 being flush with the top cover 6 and leaving a distance d2 from the bottom cover 7 ,
• wherein 8 and 9 with the respectively adjacent partition wall 9 or 8 and optionally the side covers 2 or 3 form a divided interior space (compartment),
• at least one radiation source 10 radiating within the interior space and / or into the interior space ,
• at least one gas supply device 11, with which a gas or gas mixture can be guided into the interior or formed there,
• at least one conveying device 12 for the substrate S,
• Inlet 13 and
• Outlet 14,
• In which
• the partitions 8 are substantially perpendicular to the lower cover 7 ,
• the partitions 9 are substantially perpendicular to the top cover 6 ,
• the distances d1 and d2 and the width b of the device 1 are chosen so that they are greater than the dimensions of the substrate S along the conveying direction of the conveying device 12 and
• by the devices 2, 3, 8 and 9 at least 4 compartments are formed.

Shielding gases which are heavier than air and those which are lighter than air can be used in the device according to the invention.

The molecular weight of an inert gas which is heavier than air is therefore greater than 28.8 g / mol (corresponds to the molecular weight of a gas mixture of 20% oxygen O ₂ and 80% nitrogen N ₂ ), preferably greater than 30 g / mol, more preferably at least 32 g / mol, in particular greater than 35 g / mol. Suitable examples include noble gases such as argon, hydrocarbons and halogenated hydrocarbons. Particularly preferred is carbon dioxide.

The supply of carbon dioxide may be from pressure vessels, filtered combustion gases, e.g. of natural gas or hydrocarbons, or preferably as dry ice. The supply of dry ice is considered advantageous, in particular for applications in the non-industrial or in the small industrial sector, since solid dry ice can be transported and stored as a solid in simple containers insulated with foams. The dry ice can be used as such, it is then in gaseous form at the usual temperatures of use. Another advantage of using dry ice is the cooling effect that can be used to condense and remove volatile paint components, such as solvents or water (see below).

Shielding gases which are lighter than air are those having a molecular weight of less than 28.8 g / mol, preferably not more than 28.5 g / mol, more preferably not more than 28.1 g / mol. Examples include molecular nitrogen, helium, neon, carbon monoxide, water vapor, methane or nitrogen-air mixtures (so-called lean air), particularly preferably nitrogen, water vapor and nitrogen-air mixtures, very particularly preferably nitrogen and nitrogen-air mixtures. Mixtures, in particular nitrogen.

The supply of inert gases, which are lighter than air, can preferably be carried out from pressure vessels or from oxygen-depleted exhaust gases, for example, from oxidations or coke oven exhaust gases or by separation of oxygen from gas mixtures, such. Air or combustion gases, over membranes.

The terms "protective gas" and "inert gas" are used interchangeably in this document and designate those compounds which, when irradiated with high-energy radiation, do not react significantly with the coating compositions and do not adversely affect their curing with respect to speed and / or quality. In particular, this is understood to mean a low oxygen content (see below). In it "does not mean Substantially react "that the inert gases under the applied in the process irradiation with high-energy radiation to less than 5 mol% per hour, preferably less than 2 mol% per hour and more preferably less than 1 mol% per hour with the coating materials or react with other substances present within the device.

The protective gas (mixture) is filled into the device and the air displaced from it.

The device now contains a protective gas atmosphere into which the substrate, which is coated with the radiation-curable composition, or the shaped body can be guided. Subsequently, the radiation hardening can take place.

During radiation curing, the average oxygen content (O ₂ ) in the inert gas atmosphere should be less than 15% by volume, preferably less than 10% by volume, more preferably less than 8% by volume, most preferably less than 6% by volume and especially less than 3% by volume %, in each case based on the total amount of gas in the protective gas atmosphere; With the method according to the invention, it is easy to set average oxygen contents below 2.5% by volume, preferably below 2.0% by volume and more preferably below 1.5% by volume. The particular difficulty to be considered is that three-dimensional substrates entrain oxygen into the device according to the invention (so-called scooping) and the oxygen content is therefore much more difficult to reduce than with two-dimensional objects such as films, webs or the like. In the guidance of two-dimensional substrates by the device according to the invention also lower oxygen contents than in three-dimensional to achieve, for example up to less than 1% by volume, preferably less than 0.5% by volume, more preferably less than 0.1% by volume, especially preferably less than 0.05% by volume and in particular less than 0.01% by volume.

A protective gas atmosphere is understood to mean the gas volume during the irradiation with high-energy radiation, which surrounds the substrate at a distance of up to 10 cm from its surface.

Another advantage of curing in a protective gas atmosphere is that the distances between the lamps and the radiation-curable composition can be increased in relation to the curing in air. Overall, lower radiation doses can be used and a radiator unit can be used to cure larger areas.

In the case of the use of dry ice as a protective gas, for example, a feed of the device, which may be storage containers for dry ice at the same time, easily done. The monitoring of carbon dioxide consumption is directly determined by the consumption of dry ice solids. Dry ice sublimates at -78.5 ° C directly to gaseous carbon dioxide. As a result, atmospheric oxygen is displaced upwards out of the basin in a basin without swirling.

The residual oxygen can be determined with commercially available atmospheric oxygen meters. Because of the oxygen-reduced atmosphere in the device according to the invention and the risk of suffocation associated with it, suitable safety measures should be taken. Similarly, adequate ventilation and inert gas drainage should be ensured in adjacent work areas.

• seitliche Abdeckungen 2, 3, 4 und 5,
• obere und untere Abdeckungen 6 und 7, wobei 2, 3, 4, 5, 6 und 7 gemeinsam einen Innenraum umschließen,
• eine oder mehrere Trennwände 8, die den Innenraum unterteilen, wobei die Trennwände 8 mit der unteren Abdeckung 7 abschließen und einen Abstand d1 zur oberen Abdeckung 6 freilassen,
• eine oder mehrere Trennwände 9, die den Innenraum unterteilen, wobei die Trennwände 9 mit der oberen Abdeckung 6 abschließen und einen Abstand d2 zur unteren Abdeckung 7 freilassen,
• wobei 8 und 9 mit der jeweils benachbarten Trennwand 9 oder 8 und gegebenenfalls den seitlichen Abdeckungen 2 oder 3 einen unterteilten Innenraum (Kompartiment) bilden,
• mindestens eine innerhalb des Innenraums und/oder in den Innenraum hinein strahlende Strahlungsquelle 10,
• mindestens eine Gaszuführungsvorrichtung 11, mit der ein Gas oder Gasgemisch in den Innenraum geführt oder dort gebildet werden kann,
• mindestens eine Fördervorrichtung 12 für das Substrat S,
• Einlaß 13 und
• Auslaß 14,

wobei

• die Trennwände 8 im wesentlichen senkrecht auf die untere Abdeckung 7 stehen,
• die Trennwände 9 im wesentlichen senkrecht auf die obere Abdeckung 6 stehen,
• die Abstände d1 und d2 sowie die Breite b der Vorrichtung 1 so gewählt sind, daß sie größer sind als die Dimensionen des Substrats S entlang der Förderrichtung der Fördervorrichtung 12 und
• durch die Vorrichtungen 2, 3, 8 und 9 mindestens 4 Kompartimente ausgebildet werden.

The device 1 according to the invention for carrying out a curing of coatings on a substrate S under an inert gas atmosphere contains

• side covers 2, 3, 4 and 5,
• upper and lower covers 6 and 7 , wherein 2, 3, 4, 5, 6 and 7 together enclose an inner space,
• one or more partitions 8 that divide the interior, the partitions 8 being flush with the bottom cover 7 and leaving a distance d1 from the top cover 6 ,
• one or more partition walls 9 dividing the interior space, the partition walls 9 being flush with the top cover 6 and leaving a distance d2 from the bottom cover 7 ,
• wherein 8 and 9 with the respectively adjacent partition wall 9 or 8 and optionally the side covers 2 or 3 form a divided interior space (compartment),
• at least one radiation source 10 radiating within the interior space and / or into the interior space ,
• at least one gas supply device 11, with which a gas or gas mixture can be guided into the interior or formed there,
• at least one conveying device 12 for the substrate S,
• Inlet 13 and
• Outlet 14,

in which

• the partitions 8 are substantially perpendicular to the lower cover 7 ,
• the partitions 9 are substantially perpendicular to the top cover 6 ,
• the distances d1 and d2 and the width b of the device 1 are chosen so that they are greater than the dimensions of the substrate S along the conveying direction of the conveying device 12 and
• by the devices 2, 3, 8 and 9 at least 4 compartments are formed.

An example of such a device is in the FIGS. 1 to 4 shown.

The outer walls of the device according to the invention, namely front 2 and rear 3 covers, upper 6 and lower 7 covers and side covers 4 and 5, together enclose the interior of the device first

The partition walls 8 and 9 of the device according to the invention enclose in each case together with adjacent partition walls 9 and 8 respectively with the front or rear cover 2 or 3 and with the side panels 4 and 5 and the upper and lower covers 6 and 7 compartments throughout the Divide interior of the device. A compartment is formed by enclosing this walls, which are thought to be extended over free spaces, if necessary, to close any gaps, for example, in the case of partitions 8, which are thought to be extended to the conceptual design of a compartment to the top cover 6 .

The number of compartments of the device according to the invention is at least 4, preferably at least 5 and more preferably at least 6. The number of compartments is not limited in principle, it is preferably up to 15, more preferably up to 12, most preferably up to 10 and in particular up to 8.

The partitions 8 and 9 are substantially perpendicular to the lower 7 and upper 6 cover. Therein, means essentially that the angle α1, the 8 and 7, and α 2, 9 and 6 include, by no more than 30 ° from vertical, preferably no more than 20 ° more preferably not more than 15 ° , in particular not more than 10 °, in particular not more than 5 ° and especially not at all, wherein in the construction of the device according to the invention in general the usual structural error limits are taken into account.

Advantage of such a vertical promotion is that the device according to the invention saves space and occupies the least possible footprint. In addition, the device allows at the same time a simple shielding against UV radiation to the outside, so that radiation sources without filters, e.g. against UV-C radiation, can be used for efficient radiation utilization.

The partitions 8 and 9 are up to the described deviation from the vertical parallel to the front 2 and rear 3 covers, which in turn can also deviate from the vertical.

All components of the device according to the invention are connected to each other so far that as little inert gas escapes, except from the input 12 or the output 13, from the interior, ie any cracks, gaps, slots or holes are sealed.

This also applies to the partitions, which, however, in the case of FIG. 8 need not be firmly connected to the lower cover 7 or, in the case of FIG. 9, to the upper cover 6 in order to possibly move the partitions. Here, between 8 and 7 or between 9 and 6, a narrow gap of preferably not more than 10 mm, particularly preferably not more than 7 mm, very particularly preferably not more than 5 mm, in particular not more than 3 mm and especially not more be tolerable as 1 mm.

On the other hand, the dividing wall 8 with the upper cover 6 and the dividing wall 9 with the lower cover 7 leave enough space to convey the substrate through this gap. The space between 8 and 6 leaves the space d1, the space between 9 and 7, the gap d2. The gaps d1 and d2 are designed so that they leave enough space for the dimensions of the substrate in the conveying direction of the conveyor 12 .

Of course, for the entire path through the device according to the invention along the conveying device 12, sufficient space is left for the dimensions of the substrate in the conveying direction without the substrate touching other components and / or substrates.

In principle, the substrate can be conveyed through the device according to the invention in any desired orientation, an orientation in which the flow resistance and the turbulence caused by the movement of the substrate is minimized is preferred. The projected in this orientation in the conveying direction cross-sectional area of the substrate is assumed in this document as the surface of the substrate. The dimensions present in this orientation of the substrate as conveyed by the apparatus of the invention are used herein as the characteristic dimensions of the substrate.

The substrate is preferably conveyed through the device according to the invention such that its projected cross-sectional area perpendicular to the conveying direction is as small as possible or at least not more than 25% more than this minimum, preferably not more than 20%, particularly preferably not more than 15%, especially preferably not more than 10% and in particular not more than 5%.

The cross-sectional area through which the substrate is conveyed through the individual compartments in the device according to the invention, ie the surface perpendicular to the conveyor 12 should, in a preferred embodiment according to the invention, be at least three times the projected cross-sectional area of the substrate in the conveying direction, preferably four times.

In a further preferred embodiment according to the invention, the cross-sectional area should not be more than six times the area of the substrate, preferably not more than five times.

This cross-sectional area is, for example, the cross-sectional area Q1 which leaves the partitions 8 with the top cover 6 , ie, in the case of a square opening, the area d1 · b, or the cross-sectional area Q2 which leaves the partitions 9 with the bottom cover 7, in the case a square opening the area d2 • b, or the cross-sectional area Q3 , which is formed between the partitions and optionally the walls 2 or 3 , so in the case of a square opening the area d3 • b.

The height h of the device according to the invention should be at least twice the diameter d1 or d2, whichever is the larger, preferably at least three times.

The partitions 8 and 9 are designed in a preferred embodiment so that they are displaceable parallel to the upper and lower covers 6 and 7 in order to adapt the device according to the invention to different characteristic substrate dimensions.

Such design options are known per se to the person skilled in the art. For example, the partitions may be slid in guide rails or fixed in fits or receptacles in the side and / or top and bottom covers.

The partitions 8 and 9 are designed in a further preferred embodiment so that the distance d1 or d2 to the lower or upper covers 7 and 6 is variable to adapt the device according to the invention to different characteristic substrate dimensions.

Such design options are known per se to the person skilled in the art. For example, a plurality of partitions may be arranged telescopically together, so that they can be extended or shortened by extending.

The distances d1, d2, d3 and b are preferably selected so that the distances between the substrate and the walls are as equal as possible in order to ensure the most uniform possible flow around the substrate in the inert atmosphere. The cross-sectional area formed thereby can be round, oval, ellipsoidal, quadrangular, trapezoidal, rectangular, square or irregular in shape. For the sake of simplicity, the cross-sectional area is preferably quadrangular and particularly preferably rectangular or square.

For the sake of simplicity, the inlet 13 and the outlet 14 can only be covers as openings in the front 2 or rear 3, or possibly also in a lateral 4 or 5 cover. Of course, input 13 and output 14 may also be mounted in the upper 6 or lower cover 7 .

In a preferred embodiment, input 13 and / or output 14 are made extended so that the substrate is conveyed a distance 15 of length f1 through the input 13 and / or a distance 16 of length f2 through the output 14 . These distances f1 and / or f2 may, for example, be 0 to 10 times the parameters d1 or d2, depending on which of these two parameters is the larger, preferably 0 to 5 times, particularly preferably 0 to 2-fold, most preferably 0.5 to 2-fold and especially 1 to 2-fold ( FIG. 1 ).

In a further preferred embodiment, the input 13 and / or output 14 are designed so that the substrate is enclosed as closely as possible. This can be achieved, for example, so that the openings of input and / or output come as close as possible to the dimensions of the substrate and not, as required above, form a multiple of the substrate cross-section. If the input and / or output are extended, the cross-sectional area of the extended version can taper towards the input or output.

In a further preferred embodiment, input 13 and / or output 14 are provided with devices which reduce leakage of the inert gas contained in the device from the input or output. Since the substrate at the entrance is usually coated with an uncured, so sticky coating mass, such devices should not touch the substrate at the entrance.

Examples of suitable devices are screens, brushes, curtains, curtain strips, fine meshes, springs, doors, sliding doors or locks. Of these, if desired, several can be connected in series. Pre-and post-flooders at the inputs and / or outputs are also suitable. Pre- and post-floods are inert gas-containing basins with the purpose of separating air vortex zones from the irradiation zone. For this purpose, the inert gas tank can be extended from the exposure zone both in the height and on both sides in the width. The dimensions of the receiving waters are primarily dependent on the rate of entry and exit and on the geometry of the substrate.

If both input and output are provided with such devices, it is a preferred embodiment to open and close the input and output simultaneously with these devices. That is, in the period in which a substrate passes through the entrance and the local device, such as a door, sliding door, Aperture or lock, is open, at the same time a hardened substrate passes through the output and the device located there is also open.

However, if the device according to the invention is set up in a drafty location, then it may be preferable to close the input and output reciprocally, since such a passage through the device according to the invention can be avoided.

In another preferred embodiment, the inlet and / or outlet can also be provided with devices which reduce turbulence or flow. These may be, for example, guide plates 17 or grids arranged along the conveying direction, a plurality of finely meshed nets connected in series, or guide plates 18 arranged transversely to the conveying direction, which preferably are adapted as close as possible to the substrate cross section. FIGS. 5 to 8 ).

In a preferred embodiment of the invention using an inert gas that is lighter than air, the inlet 13 and / or outlet 14 of the device according to the invention in the lower half of the device, relative to the height h of the device, attached, more preferably in the lower third and most preferably as far as possible down or in the lower cover 7 (FIG. FIG. 1 ).

In a preferred embodiment of the invention using an inert gas which is heavier than air, entry 13 and / or exit 14 of the apparatus according to the invention in the upper half of the apparatus, based on the height h of the device, mounted, particularly preferably in the upper third and most preferably as far as possible at the top or in the top cover 6 (FIG. FIG. 9 ).

The conveying mechanism 12 serves to convey the substrate S through the apparatus. Such funding mechanisms are known per se and not essential to the invention. The conveying mechanism can be arranged through the device above, below or laterally of the substrate. In a preferred embodiment, the substrate is moved through the device by a one-sided or two-sided laterally arranged conveying mechanism. This has the advantage that no abrasion from the conveying mechanism falls on the possibly still uncured substrate.

The promotion of the substrate can be done for example on conveyor belts, chains, ropes or rails. If desired, the substrate may also rotate within the device of the invention, but this is less preferred in the present invention.

If objects other than three-dimensional are conveyed through the device according to the invention, for example fibers, films or floor coverings, then the conveying device 12 can consist of rollers and / or rollers, via which the substrate is conveyed.

The device according to the invention contains at least one radiation source 10,

The radiation curing can be carried out with electron beams, X-rays or gamma rays, NIR, IR and / or UV radiation or visible light. It is an advantage of the inventive hardening under inert gas atmosphere that the radiation curing can be done with a wide variety of sources of radiation and low intensity.

Radiation sources which can be used according to the invention are those which are capable of emitting high-energy radiation. High-energy radiation is in this case electromagnetic radiation in the spectral NIR, VIS and / or UV range and / or electron radiation.

With NIR radiation here electromagnetic radiation in the wavelength range of 760 nm to 2.5 microns, preferably from 900 to 1500 nm is designated.

UV radiation or daylight comprises light in the wavelength range of λ = 200 to 760 nm, more preferably of λ = 200 to 500 nm and most preferably λ = 250 to 430 nm.

The radiation dose for UV curing, which is usually sufficient to cure the coating composition, is in the range from 80 to 5000 mJ / cm ² .

By electron radiation is meant irradiation with high-energy electrons (150 to 300 keV).

Preference according to the invention is given to NIR and / or UV radiation and particularly preferably to radiation having wavelengths below 500 nm. Very particular preference is given to radiation having a wavelength of less than 500 nm which has an exposure dose on the substrate of more than 100 mJ / sec within an exposure time of 10 seconds. cm ^{2 of} the substrate surface.

Can be considered lamps that have a line spectrum, that is radiate only at certain wavelengths, z. B. LEDs or lasers.

Also contemplated are broad band spectrum lamps, that is, a distribution of emitted light over a range of wavelengths. Intensity maxima are preferably in the range below 430 nm.

Suitable radiation sources for radiation curing are, for example, low-pressure mercury lamps, medium-pressure lamps with high-pressure lamps and fluorescent tubes, pulse emitters, Metallhaiogenidstrahler, electronic flash devices, which Radiation curing without photoinitiator is possible, or Exccimerstrahler. Mercury radiators can be doped with gallium or iron.

Radiation curing in the process according to the invention can also be effected with daylight or with lamps which serve as a substitute for daylight. These lamps emit in the visible range above 400 nm and have in comparison to UV lamps only little or no UV light components. Called e.g. Incandescent lamps, halogen lamps, xenon lamps.

Also suitable are pulsed lamps e.g. Photo flash lamps or high-power flash lamps (VISIT). A particular advantage of the method is the usability of low energy and low UV lamps, e.g. 500 watt halogen lamps, as they are used for general lighting purposes. As a result, both a high-voltage unit for power supply (in the case of mercury vapor lamps) and optionally light protection measures can be dispensed with. Also, there is no danger from ozone development in air with halogen lamps, as with short-wave UV lamps. This facilitates radiation hardening with portable irradiation equipment and enables "on-site" applications, ie independent of fixed industrial curing plants.

Any number of radiation sources can be used for the curing, each of which may be the same or different.

Optionally, a radiation source arrangement adapted to the substrate geometry and to the conveying speed is also possible in order to expose specific areas more intensively.

In order to expose difficult to access areas, especially of three-dimensional substrates, it is conceivable that at least a portion of the radiation sources and / or at least a part of existing reflectors is designed to be movable, for example on robot arms, so that, for example, shadow areas lying within substrates can also be exposed.

It may also be useful during the passage through the device according to the invention to treat the substrate first with NIR radiation and then with UV radiation.

The duration of the irradiation depends on the desired degree of hardening of the coating or of the shaped body. In the simplest case, the degree of hardening can be determined on the decoating or on the scratch resistance, for example against the fingernail or against other objects such as pencil, metal or plastic tips. Likewise, in the paint area usual resistance to chemicals, For example, solvents, inks, etc. suitable. In particular, spectroscopic methods, in particular Raman and infrared spectroscopy, or measurements of the dielectric or acoustic properties, etc., are suitable without damaging the painted surfaces.

Since the radiation sources usually provide a large amount of waste heat, which can be damaging to temperature-sensitive substrates, it may be useful not completely install the radiation sources within the interior of the device according to the invention, but to install the radiation sources so that cooling devices of the radiation sources outside the device according to the invention are mounted and illuminate the radiation sources in the device according to the invention.

This can be achieved, for example, by virtue of the fact that the radiation sources are embedded in the upper 6 or lower cover 7 and / or in the lateral covers 4 and / or 5 and the housings and / or cooling units are located outside the device according to the invention.

In a preferred embodiment of the invention, the radiation sources are completely mounted within the device according to the invention, so that the waste heat can be used for an optionally required drying of the coating composition on the substrate (see below).

Furthermore, in order to increase the utilization of the high-energy radiation, one or more reflectors may be provided in the device according to the invention, for example mirrors, aluminum or other metal foils or bare metal surfaces. In a preferred embodiment, the surfaces of the walls or covers 2, 3, 4, 5, 6, 7, 8 and / or 9 may themselves be designed as reflectors.

The at least one radiation source 10 may be positioned in the device according to the invention with respect to the total path length of the conveyor by the device according to the invention preferably in the range of 25% of the total path length up to 80% of the total path length, more preferably in the range of 33% up to 75 % of the total path length, most preferably in the range of 40% to 75%, and more preferably in the range of 50% to 75% of the total path length.

This information refers to the path length of the conveyor by the device according to the invention, i. at the entrance, this path length is 0%, at the exit 100% and in the middle 50% of the total path length.

The at least one radiation source can also be distributed over a wide range, so that a zone is formed within which is irradiated.

In a particularly preferred embodiment, at least one radiation source 10 is located in front of the gas supply device 11, viewed in the conveying direction of the conveying device 12, very particularly preferred is at least one radiation source 10 on the side covers 4 and / or 5 and / or on the partitions 8 and / or 9 ( FIG. 10 ).

This causes the flow of the inert gas, at least between the inlet 13 and the gas supply device 11 preferably in countercurrent to the conveying direction of the conveyor 12 extends.

The inert gas can be metered at any position by at least one gas supply means 11 in the inventive apparatus in principle.

The flow of inert gas can in principle be in cocurrent or countercurrent with respect to the conveying direction of the conveyor 12 move, preferably the inert gas is metered in so that the flow of inert gas between the inlet 13 and the distance at which the radiation curing of the substrate, moved in countercurrent to the conveying direction.

Preferably, the inert gas is metered in the region around and / or after the last radiation source, more preferably within a quarter of the total path length of the conveyor by the inventive device before and / or behind the zone within which is irradiated, most preferably in the range from to up to 15% of the total path length before and up to 25% behind the zone in which irradiation takes place and in particular within the range of up to 5% of the total path length before and up to 15% behind the zone within which irradiation takes place.

With the gas supply device 11 , a gas or gas mixture can be guided into the interior or formed there. The latter is of interest, for example, when the inert gas in solid, for example dry ice, or liquid form, for example as condensate or under pressure, is added to the device according to the invention and then sublimated or evaporated there.

In a preferred embodiment of the invention, the inert gas is flow and vortex low in the device according to the invention passed, for example by Strömungsvergleichmäßiger or flow straightener, such as perforated plates, sieves, sintered metal, lattice, frits, beds, honeycomb or tubular structures, preferably perforated plates or grids. By such Strömungsvergleichmäßiger or flow straightener an oblique flow or a twist are reduced.

The addition amount of the inert gas according to the invention is adapted so that it compensates for the losses of inert gas through any leaks or through the input and / or output. It is of course desirable to keep the consumption of inert gas as low as possible. In general, with the device according to the invention, the metered addition of inert gas to compensate for the loss of inert gas in addition to the conveyed material displaced and exhausted inert gas volume not more than twice the internal volume of the device according to the invention per hour, more preferably not more than the simple of the internal volume, most preferably not more than 0.5 times and in particular not more than 0.25 times the internal volume of the device according to the invention per hour.

In a preferred embodiment of the present invention using an inert gas that is lighter than air, the inert gas is fed via a gas supply device 11 in the upper third of the device according to the invention, based on the height h, more preferably in the upper quarter and most preferably in the upper cover 6.

In a further preferred embodiment of the present invention, when using an inert gas which is lighter than air, the inert gas is heated before, during or after the metered addition via a gas supply device 11 , for example to a temperature which corresponds at least to the temperature of the protective gas atmosphere to a temperature which is at least 10 ° C above the temperature of the protective gas atmosphere and very particularly preferably to a temperature which is at least 20 ° C above the temperature of the protective gas atmosphere.

In a preferred embodiment of the present invention when using an inert gas which is heavier than air, the inert gas is fed via a gas supply device 11 in the lower third of the device according to the invention, based on the height h, more preferably in the lower quarter and most preferably in the lower cover 7.

In a further preferred embodiment of the present invention when using an inert gas which is heavier than air, the inert gas before, during or after the addition is cooled via a gas supply device 11 , for example to a temperature which is below the temperature of the protective gas atmosphere, particularly preferred to a temperature which is at least 10 ° C below the temperature of the protective gas atmosphere and very particularly preferably to a temperature which is at least 20 ° C below the temperature of the protective gas atmosphere.

It represents a further preferred embodiment of the invention, in the device according to the invention to use nitrogen and carbon dioxide simultaneously as inert gases, with nitrogen via a gas supply device 11 in the upper third the device according to the invention, based on the height h, supplied, particularly preferably in the upper quarter and very particularly preferably in the upper cover 6 and carbon dioxide via a gas supply device 11 in the lower third of the device according to the invention, based on the height h, fed, particularly preferably in lower quarter and most preferably fed in the lower cover 7 , is. In a further embodiment of this embodiment, the nitrogen can be heated as described above and / or the carbon dioxide can be added cooled as described above. As a result, a density gradient of the inert gases can be achieved within the device according to the invention by overlaying.

The side covers 2, 3, 4 and / or 5, as well as the upper and lower covers 6 and / or 7 are in a preferred embodiment thermostatted or insulated designed to keep a temperature balance between the device according to the invention and the environment as low as possible , By equalizing the temperature over the outer walls, unwanted convection currents could occur within the device.

Of course, the device according to the invention can have one or more manholes or accesses, through which the interior is accessible, for example, to move partitions, to change the distances d1 and / or d2 or to replace lamps. Before entering the device, the inert gas should be removed from the interior for safety reasons and the radiation sources switched off.

Application, film formation, evaporation of Verdünnungsmittein and / or thermal pre-reactions of the coating composition is usually carried out outside the device according to the invention.

In this case, according to the invention, it generally does not matter in which temporal or spatial distance from the device according to the invention or in which way the application takes place.

The application can be applied for example by spraying, filling, doctoring, brushing, rolling, rolling, pouring, laminating, dipping, flooding, brushing, etc. on the substrate. The coating thickness is usually in a range of about 3 to 1000 g / m ² and preferably 5 to 200 g / m ² .

In a particularly preferred embodiment of the invention, the substrate coated with a coating composition is dried at least partially within the apparatus according to the invention, ie, volatile components of the coating composition are largely removed within the apparatus. Such volatile constituents may be, for example, in the coating composition contained solvents act. These may, for example, esters, such as butyl acetate or ethyl acetate, aromatic or (cyclo) aliphatic hydrocarbons, such as xylene, toluene or heptane, ketones, such as acetone, isobutyl methyl ketone, methyl ethyl ketone or cyclohexanone, alcohols such as ethanol, isopropanol, mono- or lower Oligoethylen- or -propylene glycols, mono- or di-etherified ethylene or propylene glycol ethers, glycol ether acetates such as methoxypropyl acetate, cyclic ethers such as tetrahydrofuran, carboxylic acid amides such as dimethylformamide or N-methylpyrrolidone and / or water. The evaporation and / or evaporation of solvents in the drying step within the device according to the invention has the advantage that the gaseous solvents within the dust-free device contribute to the inert atmosphere, which reduces the inert gas consumption, and additionally exerts a plasticizing effect on the coating during curing, thereby this becomes more flexible. Therefore, it is advantageous according to the invention if the inert gas atmosphere present in the device according to the invention contains at least 2.5% by volume, preferably at least 5, particularly preferably at least 7.5 and very particularly preferably at least 10% by volume a proportion of one or more Having solvents.

In a further particularly preferred embodiment, the device according to the invention additionally has a condensation possibility 19 (FIG. FIG. 11 ), in which the solvents located in the inert gas atmosphere within the device according to the invention can be condensed out. Such condensation options are preferably located at the input and / or output of the device according to the invention. These may be, for example, plate or shell-and-tube heat exchangers, cooling coils or cold fingers which are operated either with an external cooling medium in cocurrent or countercurrent, preferably in countercurrent to the conveying direction of the substrate, or preferably in the case of dry ice as the source of CO ₂ as the inert gas within the apparatus to be operated with dry ice, which is generated at the same time inert gas within the apparatus and the solvent can be recovered. The condensate is then collected and conveyed outside the device, for example by a siphon, effluent or spout, optionally with a siphon. Such condensation and optionally reuse of the solvent significantly reduces emissions and solvent consumption.

For drying the coating composition on the coated substrates within the device according to the invention, the inert gas atmosphere and / or the coating composition over a period of at least 1 minute, preferably at least 2 min, more preferably at least 3 min and most preferably at least 5 min to a temperature of at least 50 ° C, preferably at least 60 ° C, more preferably at least 70 ° C and most preferably at least 80 ° C heated.

The heat for the drying can be introduced, for example, by utilizing the waste heat of the at least one radiation source 10 or via at least one additional heating device 20 , which is located between the input and irradiation of the coated substrates. Such heaters 13 are known per se to those skilled in the art, it is preferably IR and / or NIR emitters that heat the coating composition. With NIR radiation is here electromagnetic radiation in the wavelength range of 760 nm to 2.5 microns, preferably from 900 to 1500 nm, with IR radiation, the wavelength range of 25 -1000 microns (far IR), and preferably 2.5 - 25 microns (middle IR). For drying, radiation with a wavelength of 1 to 5 μm is preferably used.

In a preferred embodiment, the radiation curing is at least partially preferably carried out completely when the coating composition on the coated substrates has a temperature of 50 ° C or more, preferably of at least 60 ° C, more preferably of at least 70 ° C and most preferably of at least 80 ° C. In this case, it is of minor importance how the coating composition is brought to this temperature, whether by heating the inert gas atmosphere and / or by radiation sources 10 and / or by additional heating devices 20 and / or in another way.

If the radiation curing is carried out at least partially at such an elevated temperature of the coating composition, the coating thus obtained has better properties. The reason for this is unclear, for example, could be a reduced viscosity of the heated coating composition.

The residence time within the device depends on whether or not additional drying is to take place within the device according to the invention. The residence time without drying within the device according to the invention, ie from the passage of the substrate through the entrance to the passage of the exit, is usually at least one minute, preferably at least 2 minutes, more preferably at least 3 minutes, most preferably at least 4 minutes and especially at least 5 minute The residence time without drying within the device according to the invention generally does not exceed 15 minutes, preferably it is not more than 12 minutes, particularly preferably not more than 10 minutes, very particularly preferably not more than 9 minutes and in particular not more than 7 minutes. Although a higher residence time usually has no adverse effect on the curing of the coating composition, but also has no positive effect and thus leads to unnecessarily large devices.

Contains the device according to the invention still an additional drying, so of course the time for drying must be added to the specified residence time.

The length of the Fördererinrichtung 12 by the device according to the invention and the speed of conveying the substrate is adapted accordingly to this residence time. The residence time of the substrate in the device depends, for example, on the substrate, as well as its size, weight and complexity of its structure, as well as reactivity, type (eg pigmentation), amount, thickness and area of the coating composition to be cured or of the coating containing it on the substrate from.

The conveying speed of three-dimensional objects through the device according to the invention can be, for example, 0.5 to 10 m / min, preferably 1 to 10 m / min, more preferably 2 to 8 m / min, most preferably 3 to 7 and in particular 5 m / min be. Objects with gas-producing parts, such as trim parts or housings for vehicles or machines, are conveyed similarly fast, but require additional measures to reduce the oxygen input, in particular by means of extended distances.

Three-dimensional objects are those whose coating with a coating composition could not be at least theoretically cured by direct irradiation from exactly one radiation source.

For sheet goods, such as films or flooring, the conveying speed can be up to about 100m / min and for the fibers to over 1000 m / min. In these cases, the conveyor 12 may include, for example, rollers and / or rollers.

It may be useful to provide within the device, two or more parallel conveyors, which promote the substrates by a common input and output but go through separate distances within the device. This has the advantage that the number of inputs and outputs over which most of the inert gas is lost is kept as low as possible.

In order to avoid the losses of inert gas, the device according to the invention should be set up in a draft-free location, since inert gas can already be sucked out of the device according to the invention by a slight flow which flows around the device. Of course, however, for safety reasons, attention must be paid to adequate ventilation of the location of the device, in order to avoid inertization of the environment, which could jeopardize the operating personnel.

In order to minimize the inert gas requirement in the device according to the invention, air flows which are present via air exchange at application and drying devices can be reduced by keeping corresponding distance to these application and drying devices or by redirecting or breaking these air flows with, for example, shielding walls.

Radiation-curable coating compositions contain radiation-curable compounds as binders. These are compounds with free-radically or cationically polymerizable ethylenically unsaturated groups. The radiation-curable composition preferably contains from 0.001 to 12, more preferably from 0.1 to 8, and very particularly preferably from 0.5 to 7, moles of radiation-curable ethylenically unsaturated groups per 1000 g of radiation-curable compounds.

As radiation-curable compounds come z. For example, (meth) acrylic compounds, vinyl ethers, vinylamides, unsaturated polyesters e.g. based on maleic acid or fumaric acid optionally with styrene as a reactive diluent or maleimide / vinyl ether systems into consideration.

Preferred are (meth) acrylate compounds such as polyester (meth) acrylates, polyether (meth) acrylates, urethane (meth) acrylates, epoxy (meth) acrylates, carbonate (meth) acrylates, silicone (meth) acrylates, acrylated polyacrylates.

Preferably, at least 40 mol%, more preferably at least 60%, of the radiation-curable ethylenically unsaturated groups are (meth) acrylic groups.

The radiation-curable compounds may contain other reactive groups, e.g. Melamine, isocyanate, epoxide, anhydride, alcohol, carboxylic acid groups for additional thermal cure, e.g. B. by chemical reaction of alcohol, carboxylic acid, amine, epoxy, anhydride, isocyanate or melamine groups containing (dual cure).

The radiation-curable compounds may be e.g. as a solution, e.g. in an organic solvent or water, as an aqueous dispersion, as a powder.

The radiation-curable compounds and thus also the radiation-curable compositions are preferably free-flowing at room temperature. The radiation-curable compositions preferably contain less than 20% by weight, in particular less than 10% by weight, of organic solvents and / or water. They are preferably solvent-free and anhydrous (so-called 100% systems). In this case, it is preferable to dispense with a drying step.

The radiation-curable compositions may contain other constituents in addition to the radiation-curable compounds as a binder. Consider, for example, Pigments, leveling agents, dyes, stabilizers etc.

For curing with UV light, photoinitiators are generally used.

Photoinitiators known to the person skilled in the art as photoinitiators can be used, for example those in " Advances in Polymer Science ", Volume 14, Springer Berlin 1974 or in KK Dietliker, Chemistry and Technology of UV and EB Formulation for Coatings, Inks and Paints, Volume 3; Photoinitiators for Free Radical and Cationic Polymerization, PKT Oldring (Eds), SITA Technology Ltd, London on, mentioned.

Suitable examples are phosphine oxides, benzophenones, α-hydroxy-alkyl-aryl ketones, thioxanthones, anthraquinones, acetophenones, benzoins and benzoin ethers, ketals, imidazoles or phenylglyoxylic acids.

Phosphine oxides are, for example, mono- or bisacylphosphine oxides, such as, for example, Irgacure® 819 (bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide), as described, for example, in US Pat EP-A 7 508 . EP-A 57 474 . DE-A 19618 720 . EP-A 495 751 or EP-A 615 980 are described, for example, 2,4,6-trimethylbenzoyldiphenylphosphine oxide (Lucirin ^® TPO), ethyl 2,4,6-trimethylbenzoylphenylphosphinate, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentyl,

Benzophenones are, for example, benzophenone, 4-aminobenzophenone, 4,4'-bis (dimethylamino) benzophenone, 4-phenylbenzophenone, 4-chlorobenzophenone, Michler's ketone, o-methoxybenzophenone, 2,4,6-trimethylbenzophenone, 4-methylbenzophenone, 2,4 Dimethylbenzophenone, 4-isopropylbenzophenone, 2-chlorobenzophenone, 2,2'-dichlorobenzophenone, 4-methoxybenzophenone, 4-propoxybenzophenone or 4-butoxybenzophenone

Examples of α-hydroxyalkyl-aryl ketones are 1-benzoylcyclohexan-1-ol (1-hydroxycyclohexyl-phenylketone), 2-hydroxy-2,2-dimethylacetophenone (2-hydroxy-2-methyl-1-phenyl) propan-1-one), 1-hydroxyacetophenone, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, polymer containing 2-hydroxy-2- contains methyl-1- (4-isopropen-2-yl-phenyl) -propan-1-one in copolymerized form (Esacure® KIP 150)

Xanthones and thioxanthones are, for example, 10-thioxanthenone, thioxanthen-9-one, xanthen-9-one, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, 2,4-dichlorothioxanthone, chloroxanthenone,

Anthraquinones are, for example, β-methylanthraquinone, tert- butylanthraquinone, anthraquinonecarbonyl acid ester, benz [de] anthracen-7-one, benz [a] anthracene-7,12-dione, 2-methylanthraquinone, 2-ethylanthraquinone, 2- tert- butylanthraquinone, 1 Chloroanthraquinone, 2-Amylanthraquinone

Acetophenones are, for example, acetophenone, acetonaphthoquinone, valerophenone, hexanophenone, α-phenylbutyrophenone, p-morpholinopropiophenone, dibenzosuberone, 4-morpholinobenzophenone, p-diacetylbenzene, 4'-methoxyacetophenone, α-tetralone, 9-acetylphenanthrene, 2-acetylphenanthrene, 3-acetylphenanthrene, 3-acetyllndole, 9-fluorenone, 1-indanone, 1,3,4-triacetylbenzene, 1-acetonaphthone, 2-acetonaphthone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1, 1-dichloroacetophenone, 1-hydroxyacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2,2-dimethoxy-1,2-diphenylethane-2 -on, 2-Benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one

Benzoins and benzoin ethers are, for example, 4-morpholinodeoxybenzoin, benzoin, benzoin isobutyl ether, benzoin tetrahydropyranyl ether, benzoin methyl ether, benzoin ethyl ether, benzoin butyl ether, benzoin isopropyl ether, 7-H-benzoin methyl ether,

Ketals are, for example, acetophenone dimethyl ketal, 2,2-diethoxyacetophenone, benzil ketals, such as benzil dimethyl ketal,

Phenylglyoxylic acids as in DE-A 198 26 712 . DE-A 199 13 353 or WO 98/33761 described or other photoinitiators, such as benzaldehyde, methyl ethyl ketone, 1-naphthaldehyde, triphenylphosphine, tri-o-tolylphosphine, 2,3-butanedione or mixtures thereof, such as
2-hydroxy-2-methyl-1-phenylpropan-2-one and 1-hydroxycyclohexyl phenyl ketone, Bls (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide and 2-hydroxy-2-methyl -1-phenyl-propan-1-one
Benzophenone and 1-hydroxycyclohexyl phenyl ketone,
Bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide and 1-hydroxycyclohexyl phenyl ketone,
2,4,6-trimethylbenzoyldiphenylphosphine oxide and 2-hydroxy-2-methyl-1-phenyl-propan-1-one,
2,4,6-trimethylbenzophenone and 4-methylbenzophenone,
2,4,6-trimethylbenzophenone and 4-methylbenzophenone and 2,4,6-trimethylbenzoyldiphenylphosphine oxide,

It is an advantage of the invention that the content of the photoinitiators in the radiation-curable composition can be low.

Preferably, the radiation-curable compositions contain less than 10 parts by weight, in particular less than 4 parts by weight, more preferably less than 1.5 parts by weight of photoinitiator per 100 parts by weight of radiation-curable compounds.

Sufficient is in particular an amount of 0 parts by weight to 1.5 parts by weight, in particular 0.01 to 1 part by weight of photoinitiator.

The radiation-curable composition can be applied by conventional methods to the substrate to be coated or brought into the appropriate form.

The radiation curing can then take place as soon as the substrate is surrounded by the protective gas.

The inventive method is suitable for the production of coatings on substrates and for the production of moldings.

Suitable substrates are, for example, wood, paper, textile, leather, fleece, plastic surfaces, glass, ceramics, mineral building materials, such as cement blocks and fiber cement boards, or metals or coated metals, preferably plastics or metals, which may for example also be present as films.

Plastics are, for example, thermoplastic polymers, in particular polymethyl methacrylates, polybutyl methacrylates, polyethylene terephthalates, polybutylene terephthalates, polyvinylidene fluorides, polyvinyl chlorides, polyesters, polyolefins, acrylonitrile ethylene propylene-diene copolymers (A-EPDM), polyetherimides, polyether ketones, polyphenylene sulfides, polyphenylene ethers or mixtures thereof.

Also mentioned are polyethylene, polypropylene, polystyrene, polybutadiene, polyesters, polyamides, polyethers, polycarbonate, polyvinyl acetal, polyacrylonitrile, polyacetal, polyvinyl alcohol, polyvinyl acetate, phenolic resins, urea resins, melamine resins, alkyd resins, epoxy resins or polyurethanes, their block or graft copolymers and blends thereof.

Preferred plastics include ABS, AES, AMMA, ASA, EP, EPS, EVA, E-VAL, HDPE, LDPE, MABS, MBS, MF, PA, PA6, PA66, PAN, PB, PBT, PBTP, PC, PE , PEC, PEEK, PEI, PEK, PEP, PES, PET, PETP, PF, PI, PIB, PMMA, POM, PP, PPS, PS, PSU, PUR, PVAC, PVAL, PVC, PVDC, PVP, SAN, SB, SMS, UF, UP plastics (abbreviated to DIN 7728) and aliphatic polyketones.

Particularly preferred plastics as substrates are polyolefins, e.g. PP (polypropylene) which may optionally be isotactic, syndiotactic or atactic and optionally non-oriented or oriented by uni- or bis-axial stretching, SAN (styrene-acrylonitrile copolymers), PC (polycarbonates), PMMA (polymethyl methacrylates), PBT (poly (Butylene terephthalate) e), PA (polyamides), ASA (acrylonitrile-Styroi-acrylic ester copolymers) and ABS (acrylonitrile-butadiene-styrene copolymers), as well as their physical mixtures (blends). Particularly preferred are PP, SAN, ABS, ASA and blends of ABS or ASA with PA or PBT or PC.

As molding may be mentioned z. B. composites z. B. containing radiation-curable composition impregnated fiber materials or fabric, or molded body for stereolithography.

Claims (25)

1. Apparatus 1 for effecting a cure of coatings on a substrate S under an inert gas atmosphere, comprising

   - side covers 2, 3, 4 and 5,

   - top and bottom covers 6 and 7, with 2, 3, 4, 5, 6 and 7 together enclosing an interior,

   - one or more dividing walls 8 which subdivide the interior, the dividing walls 8 finishing at the bottom cover 7 and leaving open a distance d1 from the top cover 6,

   - one or more dividing walls 9 which subdivide the interior, the dividing walls 9 finishing at the top cover 6 and leaving open a distance d2 from the bottom cover 7,

   - with 8 and 9, together with the respectively adjacent dividing wall 9 or 8 and, if appropriate, with the side covers 2 or 3, forming a subdivided interior (compartment),

   - at least one radiation source 10 radiating within the interior and/or into the interior,

   - at least one gas supply means 11, with which a gas or gas mixture can be passed into the interior or formed therein,

   - at least one conveying means 12 for the substrate S,

   - inlet 13 and

   - outlet 14,

   where

   - the dividing walls 8 stand substantially perpendicular to the bottom cover 7,

   - the dividing walls 9 stand substantially perpendicular to the top cover 6,

   - the distances d1 and d2 and also the breadth b of apparatus 1 being chosen such that they are greater than the dimensions of the substrate S along the conveying direction of the conveying means 12, and

   - means 2, 3, 8 and 9 form at least 4 compartments.
2. The apparatus according to claim 1, wherein the cross-sectional area through which the substrate is conveyed through the individual compartments in the apparatus are at least three times the projected cross-sectional area of the substrate in the conveying direction.
3. The apparatus according to claim 1 or 2, wherein the number of compartments is 4 to 15.
4. The apparatus according to claim 1 or 2, wherein the number of compartments is 6 to 8.
5. The apparatus according to any one of the preceding claims, wherein the inert gas atmosphere is composed predominantly of nitrogen and/or carbon dioxide.
6. The apparatus according to any one of the preceding claims, wherein the inert atmosphere has an oxygen content of below 3% by volume.
7. The apparatus according to any one of the preceding claims, wherein the height h of a compartment is at least twice as great as the greater of the distances d1 and d2.
8. The apparatus according to any one of the preceding claims, wherein the dividing walls 8 and 9 deviate not more than 30° from the perpendicular with the covers 7 and 6 respectively.
9. The apparatus according to any one of the preceding claims, wherein the cross-sectional areas, as defined in claim 2, are not more than six times as great as the projected cross-sectional area of the substrate S in the conveying direction.
10. The apparatus according to any one of the preceding claims, wherein the radiation source 10 comprises a UV wavelength λ of 200 nm to 760 nm.
11. The apparatus according to any one of the preceding claims, wherein the radiation source 10 comprises an NIR and/or IR wavelength λ of 760 nm to 25 µm.
12. The apparatus according to any one of the preceding claims, wherein the supply of gas via the gas supply means 11 takes place in a low-flow manner.
13. The apparatus according to any one of the preceding claims, wherein the entry 13 is formed over at least one length f1 which is 0 to 10 times the parameters d1 or d2, depending on which of these two parameters is the greater.
14. The apparatus according to any one of the preceding claims, wherein the exit 14 is formed over at least one length f2 which is 0 to 10 times the parameters d1 or d2, depending on which of these two parameters is the greater.
15. The apparatus according to any one of the preceding claims, wherein entry 13 and/or exit 14 are sealed with suitable means to prevent gas fluid loss.
16. The apparatus according to any one of the preceding claims, wherein the inert gas is heavier than air and the inert gas is supplied via a gas supply means 11 in the lower third of apparatus 1, based on its height h.
17. The apparatus according to claim 16, wherein the inert gas is metered in via a gas supply means 11 at a temperature which is below the temperature of the inert gas atmosphere.
18. The apparatus according to claim 16 or 17, wherein entry 13 and/or exit 14 of the apparatus are disposed in the upper half of the apparatus, based on the height h of the apparatus.
19. The apparatus according to any one of claims 1 to 15, wherein the inert gas is lighter than air and the inert gas is supplied via a gas supply means 11 in the upper third of apparatus 1, based on its height h.
20. The apparatus according to claim 19, wherein the inert gas is metered in via a gas supply means 11 at a temperature which is above the temperature of the inert gas atmosphere.
21. The apparatus according to claim 19 or 20, wherein entry 13 and/or exit 14 of the apparatus are disposed in the lower half of the apparatus, based on the height h of the apparatus.
22. The apparatus according to any one of the preceding claims, wherein the side covers 2, 3, 4 and/or 5 and also the top and bottom covers 6 and/or 7 are thermostated or insulated.
23. A method of effecting a cure of coatings on a substrate S under an inert gas atmosphere, wherein the cure is effected in apparatus according to any one of the preceding claims.
24. The method according to claim 23, wherein the temperature in the apparatus is at least partly 50°C or more.
25. The use of apparatus according to any one of claims 1 to 22 for effecting a cure of coating materials on a substrate S.

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