EP1801290A2 - Method and system for applying solid particles to a substrate - Google Patents

Abstract

The device for spraying particle-formed solid material (K) on a substrate (18) such as wood-panel or decorative paper coated with moistening- and/or adhesive resin layer, comprises a pipeline (4) having first end and second end exhibiting a free orifice (8), a container for the solid materials with a specific weight of more than 3.5 g/cm 3>, nozzle for producing a pressure difference, transfer means for transferring the substrate relative to the device and means for producing gas pressure arranged at the first end of the pipeline. The device for spraying particle-formed solid material (K) on a substrate (18) such as wood-panel or decorative paper coated with moistening- and/or adhesive resin layer, comprises a pipeline (4) having first end and second end exhibiting a free orifice (8), a container for the solid materials with a specific weight of more than 3.5 g/cm 3>, nozzle for producing a pressure difference, transfer means for transferring the substrate relative to the device and means for producing gas pressure arranged at the first end of the pipeline. The container and the nozzle are inserted into the line in such a way that in the operating condition by the pressure difference, the solid materials are transported from the containers into the line, are swirled into the pipeline and are transported up to the free orifice of the pipeline, from which the solid materials withdraw and are sprayed into the moistening- and/or the adhesive resin layer. The device shows hoses or pipes as a line and a plastic spray nozzle (10), which is located on the free orifice of the pipeline. The second end of the pipeline with the spray nozzle is stationarily or movably arranged in a plain parallel to the substrate or perpendicular to the substrate. Operating speed of the transfer means is up to 100 m/min. The solid particles have a diameter of 40-60 mu m. In the operating condition, 0.1 g/m 2> of the solid materials are sprayed on the substrate. Silanizing means for the solid materials are arranged in the line section between the container (12) and the free orifice of the line. An independent claim is included for a procedure for spraying particle-formed solid material on a substrate.

Description

The invention relates to a method and a system for introducing particulate solids into a substrate.

As a substrate mainly papers, especially carrier papers or decor papers, but especially plates and panels made of plastic, wood or wood material are referred to below, which are used on ceiling, wall or floor.

The application of particulate solids is particularly interesting when thin layers of particulate solids are to be applied to a substrate. The particulate solids are relatively heavy and hard. They have a specific gravity of more than 2 g / cm ³ , usually more than 3 g / cm ³ . The Mohs hardness is 8-10. The typical application for the present invention is the application of corundum, silicates or other particulate solids to a substrate to improve its surface properties. For example, the application of corundum improves the abrasion resistance of resin layers and surface coatings built therefrom. The essential requirement here is that the particulate solids do not form the surface of the substrate. They must be embedded in a near-surface layer to B. to achieve improved abrasion resistance. In synthetic resin layers interspersed silicates improve z. B. the scratch resistance of surface coatings.

For the application of such particulate solids, various technical solutions are known. One set of proposals is to incorporate the particulate solids into liquids from the start and to roll, lift or spread them. For example, this describes WO 00/44984 , the DE 196 04 907 or the DE 195 08 797 a dispersion containing particulate solids. These Dispersion is applied through a rinsing nozzle from below onto the respective substrate to be coated. It is also proposed to add additives to such dispersions which make the particulate solids easier to handle. As additives, fibers and / or spherical bodies (glass beads) are proposed. The disadvantage here is that the preparation and processing of the dispersion is very complex, because settling of the particulate solids must be avoided. Even in the case of brief interruptions of production, the application device must be completely cleaned, as otherwise the dispersion will add lines and nozzles. The order volume also fluctuates to a relatively high degree.

Alternatively, the beats WO 2005/042644 to scatter such particulate solids onto the substrate. Via a roller arrangement, under which the substrate is passed, particulate solids are scattered onto the substrate. This arrangement is mechanically easy to manufacture and operate, but the uniformity and accuracy of the job is not satisfactory and the mechanical wear is very high. In addition, in a second step, very expensive fibers have to be applied to the surface of the substrate and aligned in a targeted manner in order to ensure the embedding of the particulate solids.

All solutions must deal with the fact that the particulate solids such as corundum, silicates or other particles are usually very abrasive. The methods known in the art therefore attempt to minimize the contact between the particulate solids and the respective conveyors so as to minimize wear on the conveyors. The extremely complex embedding of the particulate solids in synthetic resin effectively veils the particles. Scattering via a roller arrangement avoids interfering friction wherever possible.

It is therefore an object of the invention to provide a device and a method can be applied with the particulate solids economically in a substrate and embedded in a near-surface layer.

The solution according to the invention provides a device which is suitable for spraying particulate solids onto a substrate containing a moist and / or sticky material Resin film is coated, is designed with a conduit at the first end means for generating gas pressure are arranged and the second end has a free mouth, which further comprises a reservoir for particulate solids and which is equipped with a nozzle for generating a pressure difference , wherein the reservoir and the nozzle are inserted into the conduit, that in the operating condition by the pressure difference generated by the nozzle particulate solids are transferred from the reservoir into the conduit and swirled, which are then transported to the free mouth of the line from the the particulate solids then exit and be sprayed into the moist and / or tacky synthetic resin layer.

Experiments have shown that - contrary to the previous opinion of the experts - a spraying of particulate solids on a substrate - and thus a spraying of the particles in the moist and / or sticky synthetic resin layer - is readily possible. The wear on the device is surprisingly low, especially if the solid particles are sufficiently fluidized. The device of the invention requires for spraying the particulate solids hardly moving components, which is very advantageous for industrial application. The fact that only the solid particles are sprayed, a particularly accurate distribution of the particulate solids is achieved.

The turbulence generated by the pressure difference among the solid particles is essential for uniformly spraying the particulate solid. A preferred embodiment of the device according to the invention provides that a Venturi nozzle is inserted into the conduit. It creates a negative pressure in the pipe. The Venturi nozzle is inserted into the line of the device according to the invention that, by the negative pressure which it generates, the particulate solids from the reservoir in the line tears, where the particles are swirled and carried in the gas stream until they are always still homogeneous gas-solid mixture impinge on the moist and / or tacky synthetic resin layer of the substrate, where the solid particles are deposited as a very uniform layer and sink into the wet resin layer. According to a further preferred embodiment of the device according to the invention, the particulate solids are fluidized in the operating state in the reservoir. They are preferably of air or another Inert gas flows through and are kept in this way in the reservoir in motion.

According to a further preferred embodiment, the device according to claim 1 is provided with at least one spray nozzle on the mouth. The spray nozzle makes it possible to control the coating of the substrate very precisely. Depending on the choice of nozzle, the shape of the spray cone can be adjusted as desired in order to achieve a predetermined spray result on the substrate. The shape of the spray nozzle, for example, also depends on whether the mouth of the line is stationary or movable (we will discuss this below). A wide range of nozzles or nozzle openings can be used for the device according to the invention, for example nozzles with an annular opening or nozzles with a slot-shaped opening. To broader substrates z. B. wood-based panels to coat, it is also possible to arrange several spray nozzles side by side. Several spray nozzles can communicate with the mouth of the pipe via a manifold without affecting the uniformity of the spraying process. In this case, a plurality of devices according to the invention can be arranged in parallel, which are each equipped with one or more nozzles. The nozzles are adjustable according to a further advantageous embodiment about their longitudinal and or transverse axes.

The lines of the device according to the invention can be selected depending on the application. They can be fixed pipes (pipes) or flexible pipes (hoses). Hoses are particularly advantageous when the mouth of the second end or possibly arranged thereon spray nozzle are designed to be movable. Lines and spray nozzles, but also the distributor can be made according to a preferred embodiment of the invention made of plastic. The device is thus assembled in a cost effective manner from lightweight components. It is also possible to combine components made of different materials. So z. B. the lines are each made in sections of metal and plastic. Also, ceramic components may be used for the production of the aforementioned lines, spray nozzles or manifolds.

It is preferred if the device according to the invention also has means for conveying the substrate. Depending on whether it is a decorative paper, the substrate Veneer or a wood-based material surface is simply placed on the conveyor or fixed there. It is then passed under the stationary or movable mouth or spray nozzle of the device and coated with the particulate solid. If necessary, the substrate can be fixed on the means for conveying, be it by negative pressure, be it z. B. by oppositely arranged rollers or conveyor belts. The provision of such conveying means enables the industrial-economical coating of the solid solid particle substrate.

It is regarded as a particular advantage of the invention that the device according to the invention can indeed certainly be used for itself. However, the device is preferably integrated in a system for surface coating. The application of synthetic resin or the painting of wood-based surfaces is usually carried out in impregnation or painting at working speeds of about 30 m / min to about 100 m / min, often between 40 m / min and 60 m / min. At these operating speeds, the spray device according to the invention can be readily integrated into these systems. Here, the compact design of the device proves to be very beneficial. In integrated devices conveying means are frequently provided which transport the substrates to be processed or coated through all stations of the complex coating installations.

It can be processed according to the invention, a wide range of particulate solids in the apparatus according to claim 1. Often corundum is used, but it is also conceivable the use of silicates, carbides or diamond dust. The particulate solids having a specific gravity of usually more than 2 g / cm ³ , often more than 3 g / cm ³ , are usually used in diameters of 30 to 100 .mu.m, preferably in diameters of 40 .mu.m to 60 .mu.m. They are embedded by the spraying in synthetic resin layers on the surface of carrier or decorative papers but also in synthetic resin layers directly on the surface of wood-based materials in order to improve the properties of the surface coating, typically to increase the abrasion resistance or the scratch resistance. It is preferred that the moist and / or tacky synthetic resin layer when spraying or spraying the particulate solids has a layer thickness which has at least half the average diameter of the particulate solids, so for example Layer thicknesses of 15 microns to 50 microns. When the particles are sprayed in, they are then largely enveloped by the synthetic resin by displacement of the synthetic resin. Alternatively, after the spraying process, a further synthetic resin layer can also be applied in order to complete the embedding of the particulate solids.

With the device according to the invention almost any amounts of solid particles can be applied to the substrate. It is amazing that tests have shown that even small amounts of particulate solids can be applied reliably and evenly. Quantities of up to 100 g / m ² , preferably of up to 80 g / m ² , more preferably of up to 50 g / m ² , advantageously of up to 30 g / m ² can by means of the device according to the invention with high uniformity on the Substrate are applied, and - as mentioned above - at high operating speed.

It is considered to be particularly advantageous that with the device according to the invention a high uniformity of the application of solid particles is achieved, which is clearly superior to the previously known methods. The uniformity of the particle application is important in several respects: on the one hand, an increasing application of solids adversely affects the transparency of the substrate surface. On the other hand, if there are high fluctuations in the uniformity of the order, significant safety measures must be taken when applying solid particles, if specified quantities are to be observed. This adversely affects the cost and leads to increased wear on application devices.

According to the invention, the solid particles can be scattered onto the substrate with an accuracy of up to ± 0.8 g / m ² , preferably of up to ± 0.5 g / m ² . Particularly preferably, the order accuracy is even narrower and according to the invention is up to ± 0.3 g / m ² . Advantageously, a job accuracy of up to ± 0.1 g / m ^{2 is} achieved. In known methods, the achievable distribution accuracy is greater than ± 2 g / m ² . The solution according to the invention therefore offers considerable economic and technical advantages.

The device according to the invention offers, according to an advantageous embodiment, various possibilities for individually setting the order of the particulate solids. Thus, the free mouth of the line, possibly with the attached spray nozzle, both parallel to the plane of the substrate to be coated to be arranged movable, for example, be moved on a rail over the substrate to be coated. Alternatively or additionally, the distance to the surface can also be changed. The movement of the free orifice relative to the substrate is matched to the feed rate of the conveying means, which transport the substrate through the device according to the invention. Alternatively, the device according to the invention can also be adapted to the respective substrate by the number of the spray nozzle. For example, groups of nozzles may be connected via manifolds to the mouth of the conduit to achieve a predetermined spread pattern. Due to these diverse adjustment possibilities, the application of the particulate solids can be adapted to a large extent to the substrate to be sprayed in a wide range. Application methods known from the prior art do not allow such an individual adjustment of application quantity and distribution of the particulate solids.

The device according to the invention is designed according to a preferred embodiment so that further means for modifying, in particular for coating the particulate solids in the line are provided. The modifying may be a coating, for example to impart better binding to the particulate solids on the substrate or to impart improved optical properties to the particulate solids. Often, the solid particles z. B. silanized to achieve better adhesion to the substrate. The modifying agents are inserted into the conduit between the reservoir and the mouth, the modifying agent is sprayed into the conduit or, preferably, entrained in the conduit in the same manner as the particulate solids by a pressure change, and then clad the particulate solids ,

The inventive device further allows due to the high accuracy in applying the particulate solids and applying varying amounts, ie a precise differentiation between areas where solid is applied to the substrate and areas where less, more or no solid on the substrate is applied. Substrates with discrete sections of varying amounts of particulate solids can be produced.

• Beschichten des Substrats mit einer feuchten und/oder klebrigen Kunstharzschicht
• Aufbauen von Gasdruck in einer Leitung
• Erzeugen eines Druckwechsels in der Leitung
• Verwirbeln und Mitreißen von partikelförmigen Feststoffen mit einem spezifischen Gewicht von mehr als 2 g/cm³ in die Leitung
• Einsprühen von verwirbelten, partikelförmigen Feststoffen aus der Leitung in die feuchte und/oder klebrige Kunstharzschicht des Substrats.

The inventive method provides that particulate solids are sprayed into a moist and / or tacky synthetic resin layer of a substrate with the steps:

• Coating the substrate with a moist and / or tacky synthetic resin layer
• Building gas pressure in a pipe
• Generating a pressure change in the line
• Swirling and entrainment of particulate solids having a specific gravity greater than 2 g / cm ³ into the conduit
• Spraying fluidized, particulate solids from the conduit into the moist and / or tacky resin layer of the substrate.

According to the invention, it is provided that particulate solids are sprayed into a synthetic resin layer with a moist and / or tacky surface of a substrate. The spraying of such a moist and / or tacky resin-coated substrate with particulate solids allows for very uniform coating of the substrate. Typically, it can be a substrate that has not yet reacted, or a substrate coated with paint or varnish. But it can also be a decorative paper soaked with not yet dried melamine resin. Embedding the sprayed particulate solids in the moist and / or sticky surface of the substrate requires much less use of such moist and / or tacky coating agents than conventional methods, e.g. those which apply the solid particles in the form of dispersions. The subsequent drying or curing of the moist and / or tacky coating additionally contributes to the fixation of the particulate solids. It is essential that the particulate solids penetrate as deeply as possible into the synthetic resin layer. They should not rest on the synthetic resin layer but be embedded in this layer.

It has proven to be advantageous to dry or cure the moist and / or tacky synthetic resin layer after introduction of the particulate solids. Usually, this is done in a dryer or oven, which passes through the coated substrate.

It is the object of the invention to introduce the sprayed-on particulate solid as completely as possible into the synthetic resin layer. Solid particles which do not penetrate into the synthetic resin layer or which do not adhere to the surface of the substrate can be returned to the reservoir via a suction system and subsequent sighting. If the process according to the invention is carried out in a manner in which the particulate solids do not penetrate deeply into the synthetic resin layer and are accordingly not completely enclosed by the synthetic resin, then it is advisable to subsequently apply at least one layer of synthetic resin containing the still exposed portions of the particulate Encloses solids.

The inventive method is implemented in the apparatus according to the invention described above. It is simple and straightforward in technical application, in particular it is insensitive to downtime. The special requirement of the deep penetration of the particulate solids in the resin layer is perfectly implemented. The relatively high specific gravity of the particulate solids in conjunction with the air flow causes a sufficiently deep penetration into the resin layer.

The gas pressure is built up by simple means, for example by a pump or by means of a connection to a centrally installed compressed air line. The change from the higher to the reduced pressure is expediently brought about by a nozzle, preferably by a Venturi nozzle. The particles are entrained from the reservoir due to the pressure drop generated by the nozzle in the line, about the principle of operation of the water jet pump.

According to a further advantageous embodiment of the method according to the invention, the spray cone for the solid to be sprayed onto the substrate is predetermined by a spray nozzle placed on the mouth of the pipe. The spray cone can-as described above in the description of the device according to the invention-be adapted to the individual requirements of the respective substrate by optimizing the type and orientation of the spray nozzle. The optimization of the spray nozzle is carried out by practical experiments.

For example, the spray nozzle can be designed so that the substrate is sprayed intermittently. There are then sections of the substrate z. B. web-shaped or in transverse stripes sprinkled with solid solids. For example, portions of a wall, ceiling or floor panel are sprinkled only where a particulate surface is also desired. There, where z. B. pitch saws after the scattering of the solid particles to set to separate the panels, a disturbing, wear on the saw causing coating with particulate solids can be omitted or at least significantly reduced.

The aforementioned application rates of up to 100 g / m ² and in particular the accuracy of the coating with up to 0.8 g / m ² , preferably up to 0.1 g / m ² can by tuning between gas flow, nozzle geometry, in particular the scattering nozzle and speed of the substrate moved relative to the device, but also by increasing or decreasing the distance between the substrate and the spray nozzle. It is within the usual scope to optimize such devices to achieve the optimum setting of these parameters, tailored to the particular application.

Furthermore, the invention relates to a particularly uniformly coated with solid particles substrate, wherein the particulate solid is introduced into a synthetic resin layer. Unlike previously, substrates, particularly decorative papers and panels, can be provided which are coated within close tolerances with particulate solids. The tolerance for the order quantity of the particulate solids amounts to a simple embodiment of the invention up to ± 0.8 g / m ² , according to a preferred embodiment, the tolerance is up to ± 0.5 g / m ² , more preferably up to ± 0.3 g / m ² , advantageously up to ± 0.1 g / m ² . The uniform layer distribution allows specified for the respective substrate abrasion, z. B. to achieve a certain abrasion resistance, with an overall lower use of solid particles to achieve than previously possible.

According to a preferred embodiment of the invention, the thus coated substrate is part of a multilayer surface coating. In particular, the synthetic resin layer according to the invention, which is coated particularly uniformly with corundum, is covered by a further synthetic resin layer.

Fig. 1

eine schematische Darstellung einer bevorzugten Ausführungsform der erfindungsgemäßen Vorrichtung;

Fig. 2

eine schematische Darstellung einer bevorzugten Ausführungsform der erfindungsgemäßen Vorrichtung mit mehreren Düsen;

Fig. 3

eine schematische Darstellung der Absaugung einer bevorzugten Ausführungsform der erfindungsgemäßen Vorrichtung.

Essential details of the invention are explained below using an exemplary embodiment. It shows:

Fig. 1

a schematic representation of a preferred embodiment of the device according to the invention;

Fig. 2

a schematic representation of a preferred embodiment of the device according to the invention with a plurality of nozzles;

Fig. 3

a schematic representation of the suction of a preferred embodiment of the device according to the invention.

Fig. 1 shows a device 2 for spraying particulate solids. The device 2 has a line 4, the first end 6 is connected to a here schematically indicated by "D" compressed air line. The line 4 (here with a line cross section of 6 mm) and thus also the Venturi nozzle is acted upon via the compressed air line D with an air flow volume of 1.5 m ³ / h. The second end, the free mouth 8 of the conduit 4 is provided with a spray nozzle 10. The line 4 passes through a reservoir 12 containing particulate corundum. The corundum has a specific gravity of 4 g / cm ³ . In the region of the reservoir 12 containing corundum, a Venturi nozzle 14 is inserted into the conduit 4. Due to the negative pressure generated in the venturi nozzle 14 in the operating state, corundum is sucked out of the reservoir 12 into the line via swirling via a suction line 16. The delivery air flow is 6 bar.

The container 12 is open to the environment, it is refilled regularly in accordance with the consumption of corundum. The line 4 is mainly made of stainless steel. However, it has a section 4a, which is made of flexible plastic. At least in areas where plastic components are used, the system is earthed to avoid static electricity. Due to the flexible plastic conduit 4a, the free mouth 8 can be aligned with the nozzle 10 attached thereto at exactly the desired distance from the substrate to be coated.

From the reservoir 12 occurs at the pressure ratios given above, an amount of 50 g / m ² corundum -schematisch shown with "K" - in the gas stream over and is sprayed from the spray nozzle 10. The corundum K has an average diameter of 60 microns. The corundum K is sprayed from the nozzle 10 onto the surface of the substrate 18. The substrate 18, here a high-density fiberboard (HDF board) is coated with a moist and sticky, not yet cured layer 20 of melamine resin (layer thickness 50 microns).

The spray cone 11 of the spray nozzle 10 is indicated in FIG. 1; it extends over the entire width of the HDF plate 18. The substrate 18 is passed over conveying means, which are indicated as a roller 22, under the spray nozzle 10 at a speed of 60 m / min.

In the melamine resin layer 20 50 g / m ² corundum K is sprayed with a distribution accuracy of 0.5 g / m ² . The corundum particles sink almost completely into the melamine resin layer 20. Following the spraying of the corundum particles, the melamine resin layer is dried. Since the corundum particles and the melamine resin have approximately equal refractive indices, a transparent layer is produced.

Further exemplary embodiments explain advantages of the invention:

example 1

An overlay paper with a sheet weight of 30 g / m ² and a web width of 210 cm is filled with liquid melamine resin in a squeegee-type impregnation unit. The applied amount of melamine resin is about 120 g / m ² . The solids content of the melamine resin is 50%. The impregnated overlay paper is referred to below as impregnate. 20 g / m ^{2 of} corundum powder (particle size 40 μm) are sprayed onto the impregnate on the top side of the moist impregnate using a spray device which has twelve spray heads of a width of 210 cm. The spraying devices correspond to the device shown in FIG. The web speed of the impregnate under the twelve fixed spray heads is about 80 m / min.

The corundum powder is applied with a distribution accuracy of 0.5 g / m ² on the surface of the impregnate. The corundum powder applied to the impregnate sinks into the melamine resin layer. The corundum powder is completely from the melamine resin envelops. The measured after drying thickness of the melamine resin corundum layer is about 100 microns. The extensive, if possible complete enveloping of the corundum powder by the melamine resin is a prerequisite for the desired here transparent coating.

The corundum-containing overlay paper is dried in a floating dryer to a residual moisture of 16 to 18% by weight, based on the dry content of the impregnate. Subsequently, an additional melamine layer of 30 g / m ² to 40 g / m ^{2 is} applied with a raster coater on the underside of the impregnate. When passing through further dryer zones of the suspended bed dryer, a residual moisture of from 6% by weight to 7% by weight of the impregnate is set.

The corundum-containing substrate is turned over and pressed onto a high-density fiberboard (HDF board) in combination with melamine resin-impregnated decor paper. The resulting panel can be used as a high-quality surface for laminate flooring in the abrasion class AC 4.

Example 2

An HDF plate is first decorated in direct printing in three-color printing on the top decorative. Subsequently, a melamine resin layer of 60 g / m ^{2 is} applied with a roller coater. In the still liquid melamine resin 15 g / m ² of corundum powder (grain size: 60 microns) are sprayed with a in Fig device schematically shown first.

The melamine coating with the corundum powder embedded therein is pre-dried in a hot-air dryer until the surface coating has a residual moisture content of about 15% by weight based on this. Subsequently, another protective layer of cellulose fibers and melamine resin is applied and this surface structure is precondensed with hot air so far that it is tack-free, but the melamine resin is not yet crosslinked.

The printed and coated with corundum plate is in a short-cycle press (16 sec. At 160 ° C at the plate surface, 3 N / mm ²⁾ is pressed. In this case, a melamine film is presented on the underside of the HDF plate in return, which ensures that the underside the plate is protected, and that the plate is flat. The finished panel is suitable as a panel for the decoration of walls, ceilings or floors.

Example 3

With reference to FIGS. 2 and 3, a preferred embodiment of the device according to the invention will be explained below. The same reference numerals in FIGS. 2, 3 designate the same components as in FIG. 1.

The container 12, which receives the corundum K, is provided with an air bottom 24. Through the air bottom 24, the container 12 is flowed through from its lower region by air, which fluidizes the corundum. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The assembly of venturi nozzle 14 and intake line 16 explained in more detail in FIG. 1 is shown here as an injector 26. The injector 26 supplies one or more lines 4, through which the fluidized corundum is conveyed to the spray nozzles 10. The pressure in the delivery lines is usually 0.2 to 4 bar, usually 1 to 3.5 bar.

The line or lines 4 open into a nozzle 28, which receives a plurality of nozzles 10, which are arranged distributed over the width of the substrate 18. The nozzle assembly 28 distributes the fluidized corundum K to the nozzles 10 via distributor lines 4b arranged in the nozzle assembly 28. The nozzle assembly 28 is freely adjustable in height above the substrate. Within the nozzle block 28, the nozzles 10 are freely adjustable about their axes.

The nozzle assembly 28 is surrounded by a housing 30, which is indicated in Fig. 2. To the housing 30, a suction 32 is connected. The suction unit 32 sucks the conveying air emerging from the nozzles 10 via the suction line 34. The air flow of the suction air is indicated by A in Fig. 2. This avoids unwanted turbulence over the substrate. In order to avoid the occurrence of a negative pressure, the housing 30 is open to the environment, preferably approximately at the level of the substrate 18. Thus, external air F can be sucked in to compensate for the pressure.

Fig. 3 shows a preferred embodiment of the spraying and suction device. In order to avoid deposits on the top of the nozzle block 28, an inner hood 36 is inserted into the housing 30. In addition, a cover plate 38 closes the side wall of the Nozzle stocks 28 to the inner hood 36 from. In this way, a suction channel 40, which is flowed through by the suction air A and possibly sucked external air F. The fan 32 generates through the suction line 34 this air flow. The embodiment of FIG. 3 effectively prevents deposits on the top of the nozzle block 28th

Claims (22)

Apparatus for spraying particulate solids (K) on a substrate (18) coated with a moist and / or tacky synthetic resin layer (20) with a duct (4) at the first end (6) of which (D) Generating gas pressure are arranged and the second end of a free mouth (8), with a reservoir (12) for particulate solids (K) having a specific gravity of more than 2 g / cm ³ and with a nozzle (14) for generating a pressure difference, wherein the reservoir (12) and the nozzle (14) are inserted into the conduit (4), that in the operating state by the pressure difference generated by the nozzle particulate solids (K) from the reservoir (12) in the line ( 4) transferred and swirled and transported to the free mouth (8) of the conduit (4), from which the particulate solids (K) then emerge and are sprayed into the moist and / or tacky synthetic resin layer (20). Apparatus according to claim 1, characterized in that the device (2) hoses (49) or tubes (4) as a line and possibly at least one spray nozzle (10) which is attached to the free mouth (8) of the line (4) , having. Apparatus according to claim 2, characterized in that the device (2) lines (4) and possibly at least one spray nozzle (10) made of plastic. Apparatus according to claim 1, characterized in that the second end (8) of the conduit with the optionally attached spray nozzle (10) is arranged stationary or movable, in a plane parallel to the substrate (18) and / or perpendicular to the substrate (18). , Apparatus according to claim 1, characterized in that means (22) are provided for conveying the substrate (18) relative to the device (2). Apparatus according to claim 5, characterized in that the means (22) for conveying for an operating speed of up to 30 m / min, preferably of up to 40 m / min, more preferably of up to 60 m / min, advantageously up to 100 m / min are designed. Apparatus according to claim 1, characterized in that it is designed for spraying particulate solids (K), in particular corundum, silicates, carbides, diamond dust or other metallic and / or ceramic hard material particles or mixtures of these solids. Apparatus according to claim 1, characterized in that it is designed for spraying particulate solids (K) having a diameter of 30 .mu.m to 100 .mu.m, preferably from 40 .mu.m to 60 .mu.m. Apparatus according to claim 2, characterized in that line (4), reservoir (12), nozzle (14) and possibly spray nozzle (10) are designed so that in the operating state particulate solid (K) in an amount of up to 30 g / m ² , preferably of up to 50 g / m ² , more preferably of up to 80 g / m ² , advantageously of up to 100 g / m ^{2 is} applied to the substrate (18). Apparatus according to claim 1, characterized in that line (4), reservoir (12), nozzle (14) and possibly spray nozzle (10) are designed so that in the operating state particulate solid (K) with an accuracy of up to ± 0 , 8 g / m ² , advantageously up to ± 0.5 g / m ² , preferably up to ± 0.3 g / m ² , more preferably up to ± 0.1 g / m ² onto the substrate ( 18) is applied. Apparatus according to claim 1, characterized in that the particulate solids (K) have a specific gravity of more than 3 g / cm ³ , preferably of more than 3.5 g / cm ³ . Apparatus according to claim 1, characterized in that in the conduit (4) further means for modifying, in particular coating of the particulate solid are arranged, in particular means for silanizing. Apparatus according to claim 12, characterized in that the means for modifying in the line section between the reservoir (12) and the free mouth (8) of the conduit (4) are arranged. A method of spraying particulate solids into a wet and / or tacky resin layer of a substrate comprising the steps Coating the substrate (18) with a moist and / or tacky synthetic resin layer, - Building gas pressure in a pipe (4) - generating a pressure change in the line (4) - Swirling and entrainment of particulate solids (K) with a specific gravity of more than 2 g / cm ³ in the line (4) spraying swirling, particulate solids (K) from the line (4) into the moist and / or sticky Synthetic resin layer (20) of the substrate (18). A method according to claim 14, characterized in that the moist and / or tacky synthetic resin layer is dried or hardened after introduction of the particulate solids. A method according to claim 14, characterized in that after the introduction of the particulate solids and optionally the drying or curing of the synthetic resin layer, a further synthetic resin layer is applied. A method according to claim 14, characterized in that the discharge of fluidized, particulate solids (K) from the conduit (4) by a spray nozzle (10) is adjustable. A method according to claim 14, characterized in that the fluidized, particulate solids (K) by means of a spray nozzle (10) are applied to the substrate ( 1 8), which is moved during spraying parallel and / or perpendicular to the surface of the substrate (18) , A method according to claim 14, characterized in that the particulate solid (K) in an amount of up to 100 g / m ^{2 is} applied to the substrate (18). A method according to claim 14, characterized in that the particulate solid (K) with an accuracy of up to ± 0.5 g / m ² , preferably of up to 0.1 g / m ^{2 is} applied to the substrate (18). Substrate, in particular wood-based panel or decor paper, at least partially coated with a synthetic resin, in which a particulate solid (K) is introduced, characterized in that the particulate solid (K) with an accuracy of up to ± 0.8 g / m ² , preferably of up to ± 0.5 g / m ² , more preferably of up to ± 0.3 g / m ² , preferably of up to 0.1 g / m ^{2 is} applied to the substrate. Substrate according to Claim 21, characterized in that a further synthetic resin layer is applied to the synthetic resin layer mixed with particulate solid.

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