Applicator for applying coating medium to substrate

Abstract

The invention relates to an applicator (1) for coating a substrate (2) with a coating medium (3), the applicator (1) having at least one supply line (4) for the coating medium, an end plate (9) having at least one nozzle (5) for applying the coating medium to the substrate (2), and a chamber (6) in which the coating medium can be distributed before being applied to the substrate (2), wherein at least one nozzle (5) is inclined laterally. The invention also relates to applicator systems, devices, methods and uses associated with the applicator.

Description

[0001] The present invention relates to an applicator and to a system, a device and a method for applying a coating medium to a substrate. The substrate itself is used, for example, for catalytic exhaust gas aftertreatment, in particular for the automotive industry. Prior art

[0002] In the chemical industry, substrates or substrate monoliths are used as catalyst supports. They also play an important role in automobile exhaust treatment. In order to remove emissions that are harmful to the environment and health from the exhaust of motor vehicles, a variety of catalytic exhaust purification technologies have been developed, the basic principle of which is generally based on guiding the exhaust gas to be purified over a substrate (e.g. a flow-through or wall-flow honeycomb or monolith) on which a catalytically active coating is applied. The catalyst promotes the chemical reaction of various exhaust gas components to form harmless products (such as carbon dioxide and water).

[0003] The flow-through or wall-flow monoliths described above are also referred to as catalyst supports, supports or substrate monoliths, because they carry a catalytically active coating on their surface or in the pores of the wall forming the surface. The catalytically active coating is usually applied to the catalyst support in the form of a suspension (usually referred to as a washcoat in the case of catalysts for exhaust gas purification) in a coating process. Many such processes have been published in the past by manufacturers of automotive exhaust gas catalysts (WO9947260A1, EP2521618B1, EP1136462B1, EP1900442A1).

[0004] Although these methods are known in the prior art, uniform coating of substrate monoliths remains a challenge. For example, due to the high cost of precious metals and rare earths, different coating amounts should be avoided as much as possible. From a catalytic point of view, a uniform coating is also preferred. Dripping of the coating medium after its application to the substrate also poses a challenge to the production of the substrate.

[0005] Important aspects of this method are the precise and uniform coating of the channel interior of such a catalyst support with the coating medium (washcoat), in particular with regard to, for example, the coating length in the substrate opening, the amount of coating applied, the uniformity of the coating thickness, the uniformity of the coating length or the uniformity of the coating gradient along the longitudinal axis of the catalyst support, and the production of layered or zoned coating designs.

[0006] Producing precise and uniform coatings is particularly challenging because the channels of the catalyst support that uniformly introduces the coating are very narrow. For example, typical catalyst supports for exhaust aftertreatment have approximately 31 and 140 cells / cm 2(200 and 900 cells / square inch, cpsi), so that the opening of the catalyst channel is generally within the range of one tenth of a millimeter. Uniform coating is also complicated because the coating medium is a suspension of inorganic particles, which generally has a relatively high viscosity. In principle and especially when the process changes are small, there is a risk that each channel is unevenly loaded with the coating medium. This causes the penetration depth of the coating medium in the catalyst support to vary greatly in the local area. The uneven distribution of the catalytic coating may cause the performance of the coated catalyst to deteriorate when used as expected. However, since this coating method is performed on a plurality of substrates on an industrial scale, high uniformity and precision are required. Since the coating contains precious metals (such as platinum and palladium) and rare earths, it is also necessary to use it effectively for cost reasons.

[0007] EP2415522A1 discloses a coating method for a catalyst carrier, in which a coating medium is applied to a substrate from above. Via a die, the coating medium is guided into a cavity via a supply line and then applied to the substrate through a nozzle of an end plate. First, the entire amount of the coating medium for the catalyst carrier is introduced into a zone above the substrate and then sucked into a channel by applying negative pressure. The zone above the catalyst carrier can be defined laterally by a housing. In order to obtain multiple uniformly coated substrates in industrial production, it is required to always apply the same amount of coating medium uniformly distributed in the zone above the substrate.

[0008] Another difficulty with this method is that the coating medium is discharged from the end plate at a positive pressure. In this way, a precisely predetermined amount of a relatively viscous coating medium can be uniformly applied and distributed in the area above the substrate. If the pressure is too low, undesirable variations in the amount and distribution can result, because, for example, a portion of the coating medium remains in the nozzle of the end plate, drips in an undesirable manner or may accumulate under the end plate. In contrast, if the coating medium is discharged at a positive pressure, a predetermined amount can be precisely metered and evenly distributed. However, discharge under positive pressure may have the undesirable effect that the impact of the coating medium on the substrate and the subsequent filling of the area above the substrate may produce irregularities, which in turn lead to an uneven coating.

[0009] This undesirable effect is particularly problematic on an industrial scale where the catalyst support is coated in a short time. In practice, such an automated coating process typically takes less than 20 seconds, and typically only about 4 to 10 seconds.

[0010] In industrial processes, if exactly the same amount of coating medium is not always used, if the coating medium is not uniformly sucked into the channels or does not arrive uniformly down in the channels, the coated substrates may deviate from each other and have considerable irregularities in coating thickness, uniformity and depth in the channels. In practice, even with precise control of metering, uniform suction and drying of the coating medium, coated substrates with considerable variations in the coating in the channels may be obtained. Figure 7 The cross section of the catalyst carrier coated with the typical method according to the prior art is shown by way of example. Although the coating medium is uniformly applied and sucked into the channel of the substrate from the end plate, the channel is not uniformly coated. Therefore, the darker coating medium has deeply penetrated into the channel in some areas, but in other areas where the light-colored uncoated area is much larger, the coating medium penetrates very little. In general, an irregular zigzag pattern can be seen. Too much coating medium is usually introduced into the channels and areas coated too deeply. This also causes the coating thickness in such channels to be greater than expected. Therefore, the catalyst channel is tapered, which reduces the flow rate of the tail gas. When used as expected, this local variation of catalyst performance and flow rate causes the catalyst performance to decrease. In the area where the coating depth is too low, the tail gas is not fully purified, and in the area where the penetration depth is too high, the flow rate is reduced, and the coating medium usually containing rare and expensive metals is wasted.

[0011] Another challenge is that many products require area coating from both sides of the substrate. For technical reasons, the areas with different catalytic coatings must be as close to each other as possible, but must not overlap at the same time. Therefore, in the case of such multiple coatings, flat and straight area profiles are particularly important.

[0012] Therefore, there is a need for improved apparatus and methods for coating catalyst supports that overcome the aforementioned disadvantages.

[0013] Purpose of the Invention

[0014] The object of the present invention is to provide a device and a method by means of which a precise and uniform coating of a substrate with a coating medium can be achieved. In particular, a uniform application of the coating medium into parallel channels of a catalyst support for an exhaust gas purification device is to be achieved so that the channels can be coated as uniformly as possible and with a defined length. These methods can be carried out in an efficient and timely manner and with high throughput on an industrial scale.

[0015] Subject matter of the invention

[0016] The basic object of the invention is achieved by an applicator, a method and a use according to the claims. The subject matter of the invention comprises an applicator for coating a substrate with a coating medium, wherein the applicator has at least one supply line for the coating medium, an end plate with at least one nozzle for applying the coating medium to the substrate, and a cavity in which the coating medium can be distributed before being applied to the substrate, characterized in that at least one nozzle is laterally inclined.

[0017] First, the coating medium is introduced into the cavity of the applicator through a supply line, and then the coating medium is pushed out of the cavity under pressure through the nozzle of the end plate. The applicator allows the coating medium to be accurately metered onto a substrate, such as a substrate monolith for automobile exhaust aftertreatment. With the aid of the applicator, a predetermined amount of coating medium to be applied to the substrate is applied to the zone above the substrate. The zone above the substrate can be defined, for example, at the bottom by the end face of the substrate (with an opening of a channel) and on the side by a collar. During discharge from the applicator, the coating medium remains in the zone above the substrate without applying negative pressure and the coating medium is sucked in. Only when the coating medium of the entire amount of the substrate to be coated has been introduced into the zone, it is sucked into the substrate from the zone by applying negative pressure.

[0018] It has proven advantageous that the applicator is designed to have the approximate diameter and / or shape of the end face of the substrate to be coated. Large diameter substrates require larger applicators than small diameter substrates. Generally speaking, the diameter of the applicator ranges from 50-400mm, more preferably from 75-350mm.

[0019] Preferably, the cross section of the zone corresponds to the cross section of the substrate and the cross section of the end plate. In this way, a uniform loading of the zone can be achieved and subsequently the coating medium can be uniformly sucked into the substrate.

[0020] When viewed in a vertical view from the direction of discharge of the coating medium, the end plate preferably has a symmetrical cross section. For example, the end plate can have a circular, oval, trapezoidal, square, rectangular or polygonal (e.g. hexagonal) cross section. The shape of the end plate is preferably adapted to the cross section of the catalyst support.

[0021] Preferably, the cross section of the end plate is circular or oval. This is advantageous on the one hand because catalyst supports usually have a circular or oval cross section. In addition, it has been found that with a circular end plate having laterally inclined nozzles, the coating medium can be applied particularly uniformly to the catalyst support. In particular, with a plurality of laterally inclined nozzles, a particularly uniform circular application pattern can be obtained.

[0022] Preferably, the geometry of the nozzle arrangement corresponds substantially to the cross section of the plate. For example, the nozzles are preferably arranged in a circular pattern on a circular end plate. This facilitates optimal use of the space in the applicator and prevents the coating medium from not being applied or only being applied unevenly to a sub-area of ​​the catalyst support.

[0023] The thickness of the end plate is preferably 2 to 10 mm, more preferably 4 to 5 mm. The end plate preferably has a disc shape. Preferably, the cross section of the end plate is circular, wherein the shape is preferably cylindrical. This circular design enables a particularly uniform or symmetrical arrangement of the nozzles, so that the coating medium is applied uniformly to the substrate.

[0024] The coating medium is discharged from the applicator through the nozzle of the end plate. Preferably, the end plate includes a plurality of nozzles. The term "nozzle" refers to the component of the end plate from which the coating solution is applied to the substrate. The nozzle includes a flow channel with openings on the inlet side and the outlet side of the end plate. On the inlet side, the coating solution can be pushed out of the cavity of the applicator into the channel of the nozzle. On the outlet side, the coating medium is discharged and applied to the substrate.

[0025] According to the invention, at least one nozzle is inclined. Here, "inclined" means that the nozzle is not arranged perpendicularly to the end plate as in the case of conventional plates, but is inclined relative to the end plate. If the plate is not planar, the nozzle is inclined relative to a vertical view of the end plate from the bottom side (i.e. from the discharge side).

[0026] According to the invention, the inclination of the nozzle is lateral. In this context, "lateral" means that in a vertical view of the end plate (from below), the nozzle is not only inclined towards the center of the end plate or (outwardly) away from the center of the end plate. The lateral direction is therefore a direction at right angles to the direction towards the center. The lateral inclination of the nozzle causes the coating medium to be discharged from the nozzle at a lateral inclination, i.e. at least partially in a direction that is not towards the center or away from the center.

[0027] If the end plate has a circular or oval cross section, "laterally inclined" means that the nozzle is inclined exclusively or especially in a tangential direction when viewed from a vertical view of the end plate (from below). The tangential direction is at right angles to the radial direction of the circular or oval end plate.

[0028] In a preferred embodiment, at least one nozzle is substantially laterally inclined. This means that the nozzle is only laterally (tangentially) inclined, or the inclination is only slightly deviated from the lateral direction (in the case of a circular or elliptical plate: the tangential direction), for example less than 10 °, particularly less than 5 °. Therefore, the nozzle will not or only slightly tilt toward the center of the plate or outward (in the radial direction). In these embodiments, the coating medium is discharged substantially or only toward the side, and not toward or only slightly toward the center or edge of the coated plate. This has the following advantages: the coating solution will not accumulate on the substrate at any point, especially if most of the nozzles are aligned in the same way. In contrast, if the nozzle is tilted toward the center, more coating medium is applied toward the center. If the nozzle is tilted outward, more coating medium is applied outward, while less coating medium is discharged toward the center. The slight tilt of the laterally inclined nozzle toward the center may also be advantageous for uniform application, so that each nozzle is slightly tilted toward the adjacent nozzle.

[0029] The lateral inclination of the nozzle causes the coating medium to be discharged from the nozzle obliquely toward the side, rather than being discharged from the end plate in a vertical jet. Surprisingly, it has been found that a particularly uniform coating can be obtained if the nozzle of the end plate is laterally inclined. Assuming that in this embodiment, it is particularly advantageous that the coating medium hits the substrate laterally. On the one hand, this reduces the impact force. Applying the coating medium in the form of an inclined jet may also make it more evenly distributed on the substrate. Another advantage seems to be that the coating medium does not penetrate or only slightly penetrates into the channel of the substrate before the coating medium is specifically sucked into the channel with negative pressure. The laterally inclined nozzle may also have the following effect: the coating medium is quickly distributed on the substrate in the lateral direction after the impact, thereby even further weakening the impact force of the jet during the further application process. In general, with the help of the applicator according to the present invention, a single channel of the substrate can be coated particularly evenly, wherein in particular a particularly uniform penetration depth can be achieved.

[0030] The nozzle need not be laterally inclined along its entire length. Only the lower region needs to be inclined toward the outlet opening. For example, a laterally inclined nozzle may include a straight hole in the end plate and a laterally inclined connector on the outlet side.

[0031] In a preferred embodiment, the inclination angle of at least one nozzle is between 2° and 50°, preferably between 10° and 40°, and particularly preferably between 15° and 30°. The inclination is defined relative to a vertical view of the plate from below. It has been found that with such an inclination angle, the advantages in terms of the uniformity of the coated product can be particularly pronounced.

[0032] Preferably, the majority of the nozzles in the end plate have a lateral inclination. According to the invention, it is preferred that at least 80% (in particular at least 90% or at least 95%) of the nozzles in the end plate are laterally inclined. In a preferred embodiment, the nozzles are not or only slightly inclined towards the center or outwards (in radial direction).

[0033] The end plate according to the invention preferably comprises a plurality of nozzles. Preferably, the end plate comprises 10 to 500 nozzles, in particular 60 to 320 nozzles, or particularly preferably 95 to 225 nozzles. Such a high number of nozzles enables uniform application of the coating medium and reduces local variations in the coating.

[0034] Preferably, nozzles are arranged as evenly as possible and the distances between each other are as equal as possible. In a preferred embodiment, all nozzles are equal to the distances of their adjacent nozzles. This arrangement is advantageous in order to realize the uniform introduction as much as possible of the coating medium and the uniform coating as much as possible of the substrate.

[0035] In a preferred embodiment, the end plate comprises laterally inclined nozzles and optionally a central nozzle. The central nozzle may be inclined or non-inclined. Preferably, all nozzles are laterally inclined, while the central nozzle is non-inclined. With this arrangement, a particularly uniform application of the coating medium to the substrate can be achieved, since all nozzles except the applicable central nozzle discharge the coating medium in the form of an inclined jet. With this arrangement, a particularly uniformly coated substrate can be obtained.

[0036] In another embodiment, the end plate has at least one inclined nozzle instead of a central nozzle, which directs the jet obliquely toward the center of the catalyst support body (in a vertical view). In this way, even without a central nozzle in the end plate, the coating medium can be applied uniformly to the center of the catalyst support body.

[0037] In a preferred embodiment, all nozzles of the end plate are arranged symmetrically, in particular rotationally symmetrically. Preferably, the laterally inclined nozzles are arranged in concentric circles around a central non-inclined nozzle. Preferably, the plate comprises a central nozzle and 2 to 9 hole rings, each hole ring having 6 to 54 nozzles on the periphery. The nozzles are arranged at a distance from each other that is as uniform as possible. The arrangement in concentric circles is particularly advantageous because a uniform distribution of the nozzles is possible in a structurally simple manner. In a preferred embodiment, the nozzles of the concentric circles are aligned in the same manner. Each nozzle can be inclined tangentially or towards an adjacent nozzle in the same manner. Thus, a particularly uniform distribution of the coating medium to the substrate is achieved.

[0038] In a preferred embodiment, the nozzles are arranged in a spiral. The nozzles are directed spirally outward from the center of the plate. With this arrangement, a uniform application of the coating medium to the substrate can also be achieved.

[0039] In a preferred embodiment, the nozzles are at a distance of between 4 and 20 mm, preferably between 6 and 10 mm, from one another relative to the center of the discharge opening in each case. Preferably, all distances of adjacent nozzles in the end plate, in each concentric circle and / or in the spiral arrangement are identical.

[0040] The diameter of the discharge opening of the nozzle is preferably between 0.5 and 5 mm, particularly preferably between 1.6 and 3 mm. Preferably, all nozzles in the plate have discharge openings of the same diameter. This enables a particularly uniform application and coating of the substrate. With such a nozzle, the coating medium can be applied particularly effectively to a substrate, which is a catalyst support for an exhaust gas purification device having fine parallel channels.

[0041] Alternatively, the coating medium may be applied unevenly to the substrate. In this way, a coating having a gradient may be achieved. Thus, for a specific application, it may be advantageous to adjust a higher concentration of the catalytic coating in the inner or outer channels. For example, a gradient may be achieved if the outlet openings of the nozzles differ from one another in the sub-zones of the plate and / or if the inclination of the nozzles varies so that more coating solution is discharged in some zones than in other zones.

[0042] Preferably, the nozzles are designed in the form of connecting pieces. This means that they protrude from the end plate towards the discharge side. The design as connecting pieces is advantageous because the lateral inclination can be adjusted relatively simply and stably in construction and makes gluing of the plates from below difficult. Preferably, the nozzles have a length of 5 to 15 mm, more preferably a length of 6 to 8 mm. The height of the protrusion above the edge of the end plate is about 0.5 to 2.9 mm, more preferably 1.5 to 2.5 mm. In a preferred embodiment, the connecting piece of the nozzle has a concave or countersunk nozzle facing the outflow direction. The distance between the nozzles is preferably in the range of 5 to 20 mm, most preferably 8 to 14 mm. In another embodiment, the nozzles can be channels that do not protrude from the plate, for example in the form of holes.

[0043] The nozzles in the end plates, preferably in the form of connectors, can have any shape and cross-section (e.g., channels, slots, circular, spiral, etc.). In the simplest case, the nozzles are channels of circular cross-section. The nozzles and / or outlet openings of the end plates are preferably of the same size.

[0044] The chamber, the end plate with the nozzles are preferably matched to one another in terms of their dimensions and their design, so that the coating medium is distributed evenly on the substrate to be coated.

[0045] The entire applicator is preferably made of plastic. However, it can also be made completely of metal. The material is selected to withstand catalytically active coatings for automobile exhaust aftertreatment. The material PE-HD 1000 is preferably used as plastic. Parts made of metal are preferably made of stainless steel that is equal to or similar to material number 1.4571 (X6CrNiMoTi17-12-2).

[0046] In a preferred embodiment, a baffle is arranged in the cavity and blocks the coating medium from flowing from the supply line to at least one opening. The coating medium is preferably metered into the applicator by a pump. The baffle may be fixedly arranged. Alternatively, the baffle may be reversibly movable. In this case, the baffle preferably blocks the flow of the coating medium in an unpressurized state, and allows the coating medium to flow from the supply line to at least one opening when the coating medium applies pressure on the baffle. The pressure established via the coating medium is used to displace the baffle of the applicator so that the path to the end plate is opened. The coating suspension can then be pressed into the cavity of the applicator, for example, by a nozzle in the baffle. Since the baffle inside the applicator is closed in an unpressurized state, dripping of the coating medium onto the end face of the substrate does not occur. With this displaceable baffle, the metering accuracy of the coating medium on the substrate can be even further improved.

[0047] Applicators and methods can be used to coat multiple substrates. Preferably, the interior of the coating substrate. Preferably, the substrate has multiple channels, which are particularly parallel to each other and are particularly loaded with the coating medium from one side (particularly by suction). Particularly preferably, the substrate is a catalyst carrier for exhaust gas aftertreatment. The channels are preferably filled so that their interior is coated, but not completely filled, so that after the coating is dried, they are still permeable to fluids (such as exhaust gases).

[0048] It is advantageous to use an applicator to produce substrate monoliths with a catalytically active coating for automobile exhaust aftertreatment. The coating medium used here is usually a suspension (slurry, washcoat), which can have an acidic or alkaline nature, but at least has a strong abrasive effect (see below). This must be appropriately taken into account in the advantageous design of the applicator according to the invention. The coating medium to be used is well known to the person skilled in the art.

[0049] The substrate is preferably a wall-flow or flow-through catalyst carrier, in particular in the form of a monolith. In the prior art, flow-through monoliths are common catalyst carriers, which may be composed of metals (corrugated carriers, for example WO17153239A1, WO16057285A1, WO15121910A1 and the literature cited therein) or ceramic materials. Preferably, refractory ceramics such as cordierite, silicon carbide or aluminum titanate are used. The number of nozzles per unit area is characterized by the cell density, which is generally between about 1,300 and 5,800 cells / cm2 (200 to 900 cells per square inch, cpsi). For ceramics, the nozzle wall thickness is between 0.5 and 0.05 mm.

[0050] All common ceramic materials in the prior art can be used as wall-flow monoliths or wall-flow filters. Preferably, a porous wall-flow filter substrate made of cordierite, silicon carbide or aluminum titanate is used. These wall-flow filter substrates have an inlet opening and an outlet opening, wherein the outlet-side end of the inlet opening and the inlet-side end of the outflow opening are closed with an airtight "plug" in a manner offset from each other. In this case, the exhaust gas to be purified flowing through the filter substrate is forced to pass through the porous wall between the inlet opening and the outflow opening, which results in an excellent particle filtering effect. The porosity, pore / radius distribution and thickness of the wall allow the filtration properties to be designed for the particles. The porosity of uncoated wall-flow filters is generally greater than 40%, generally 40% to 75%, in particular 50% to 70% (measured according to the latest version of DIN 66133 on the date of submission). The average pore size (diameter) of the uncoated filter is at least 7 μm, e.g. 7 to 34 μm, preferably greater than 10 μm, particularly more preferably 10 to 25 μm, or most preferably 15 to 20 μm (measured according to the latest version of DIN 66134 at the filing date).

[0051] The coating medium is preferably a suspension. The solvent is preferably water. Such a coating medium is referred to as a washcoat in the technical field. Preferably, the coating medium is shear-thinning (https: / / de.wikipedia.org / wiki / Strukturviskosit%C3%A4t). At a shear rate of 1001 / s, the viscosity is preferably 1.0087 to 1000 mPas, preferably 100 to 780 mPas. The viscosity can be measured, for example, with a viscometer according to EN ISO 3219. The coating medium (particularly in the form of a washcoat) comprises a solid and contains a catalytically active component or its precursor and an inorganic oxide, such as aluminum oxide, titanium dioxide, zirconium oxide, cerium oxide or a combination thereof, wherein the oxide may be doped with, for example, silicon or lanthanum. Oxides of vanadium, chromium, manganese, iron, cobalt, copper, zinc, nickel or rare earth metals such as lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium or combinations thereof can be used as catalytically active components. Precious metals such as platinum, palladium, gold, rhodium, iridium, osmium, ruthenium and combinations thereof can also be used as catalytically active components. These metals can also be present as alloys with each other or with other metals or as oxides. In the liquid coating medium, the metal can also be present as a precursor, such as nitrates, sulfites or organic compounds of the mentioned precious metals and mixtures thereof; in particular, palladium nitrate, palladium sulfite, platinum nitrate, platinum sulfite or Pt(NH3)4(NO3)2 can be used. The catalytically active component can then be obtained from the precursor by calcination at about 400°C to about 700°C.

[0052] For example, metal ions from the group of platinum metals (in particular platinum, palladium and rhodium) have been shown to be suitable for the oxidation of hydrocarbons, while the SCR reaction has been shown, for example, to be most effective for zeolites or zeolite types (molecular sieves with other or additional elements as cations in the framework compared to zeolites) exchanged with iron ions and / or copper ions. Therefore, the material causing the catalytic activity (washcoat) may also contain zeolites or zeolite types. All types or mixtures of these types that are considered by the skilled person for the corresponding application range can in principle be used as zeolites or zeolite types. This includes naturally occurring but preferably synthetically produced zeolites. These zeolites may include framework types, for example from the group consisting of beta zeolite, ferrierite, Y zeolite, USY zeolite, ZSM-5 zeolite, ITQ zeolite. Examples of synthetically produced small pore zeolites and zeolite types contemplated herein are those belonging to the following structural types: ABW, ACO, AEI, AEN, AFN, AFT, AFX, ANA, APC, APD, ATN, ATT, ATV, AWO, AWW, BIK, BRE, CAS, CDO, CHA, DDR, DFT, EAB, EDI, EPI, ERI, ESV, GIS, GOO, IHW, ITE, ITW, JBW, KFI, LEV, LTA, LTJ, MER, MON, MTF, NSI, OWE, PAU, PHI, RHO, RTE, RTH, SAS, SAT, SAV, SIV, THO, TSC, UEI, UFI, VNI, YUG and ZON. Preferred for use are those small pore types derived from the structural types consisting of CHA, LEV, AFT, AEI, AFI, AFX, KFI, ERI, DDR. Particularly preferred here are those derived from CHA, LEV, AEI, AFX, AFI or KFI frameworks. In this context, AEI or CHA type zeolites are most particularly preferred. Mixtures of the substances mentioned are also possible. The SAR value of the zeolite or the corresponding value of the zeolite type (e.g. SAPO-> (Al+P) / 2Si) should be in the range of 5 to 50, preferably 10 to 45, most preferably 20 to 40. In order to obtain corresponding good activity, for example in SCR reactions, zeolites or zeolite types (especially small-pore zeolites) need to be exchanged with metal ions (especially transition metal ions). Here, those skilled in the art can use metal ions (especially copper ions) preferably used for corresponding reactions. Those skilled in the art know how this ion exchange occurs (e.g. WO2008 / 106519A1). The exchange level (number of ions at the exchange site / total number of exchange sites) should be between 0.3 and 0.5. The exchange site here is the site where the positive ions compensate for the negative charge of the lattice. Preferably, further non-exchanged metal ions may also be present in the finished SCR catalyst, in particular Fe ions and / or Cu ions.The ratio of exchanged ions to unexchanged ions is >50:50, preferably 60:40 to 95:5, and highly preferably 70:30 to 90:10. The ions located at the exchange sites are visible in electron spin resonance analysis and can be quantitatively determined (Quantitative EPR, Gareth R.Eaton, Sandra S.Eaton, David P.Barr, Ralph T.Weber, Springer Science & Business Media, 2010). All non-ion exchange cations are located elsewhere inside or outside the zeolite / zeolite type. These non-ion exchange cations do not compensate for any negative charge of the zeolite / zeolite type framework. These non-ion exchange cations are invisible in EPR, so they can be calculated according to the difference between the total metal loading (e.g., determined by ICP) and the value determined in EPR. Control the addition of corresponding ions to the coating mixture so that the total amount of metal ions (particularly Fe ions and / or Cu ions) in the final total catalyst is 0.5 to 10 weight % of the coating amount, preferably 1 to 5 weight %.

[0053] In addition to the components discussed above, the coating medium may also contain other ingredients. These components may further support the catalytic function of the catalytically active material, but they themselves do not actively participate in the reaction. The material used here is, for example, a so-called binding agent. The binding agent especially ensures that the materials and components participating in the reaction can be sufficiently firmly adhered to the corresponding substrate. In this context, the binding agent selected from aluminum oxide, titanium dioxide, zirconium dioxide, silicon dioxide or their oxide hydroxides (such as boehmite) or their mixture has been shown to be a favorable component. Advantageously, high surface aluminum oxide is used in the present case. The binding agent is used in a certain amount in the coating. Based on the solid material used in the coating suspension, the consumption of the other components (such as binding agents) is a maximum of 25 weight %, preferably a maximum of 20 weight %, and most particularly preferably 5 weight % to 15 weight %.

[0054] The substrate monolith produced in this way and having catalytic activity in exhaust gas aftertreatment can in principle be used in all exhaust gas aftertreatments known to those skilled in the art for the automotive exhaust industry. Preferably, the catalytic coating of the substrate monolith can be selected from the group consisting of a three-way catalyst, an SCR catalyst, a nitrogen oxide storage catalyst, an oxidation catalyst, a soot ignition coating. With regard to the individual catalytic activities discussed and their explanations, reference is made to the statements in WO2011151711A1.

[0055] The subject matter of the present invention also includes a method for coating a substrate with a coating medium by means of an applicator according to the invention, comprising the following steps:

[0056] (a) applying a coating medium to the substrate through nozzles of the end plate, and

[0057] (b) The coating medium is drawn into the substrate.

[0058] The application of coating medium in step (a) occurs in the zone above substrate. Due to the at least partial tilted arrangement of nozzle, coating medium is applied to substrate with tilted jet, thereby produces particularly uniform coating. Only when the coating medium of the whole amount for substrate has been supplied in this zone, coating medium is just sucked into substrate in step (b). Suction is carried out by applying negative pressure (particularly vacuum). In step (a), coating medium is preferably applied by pressure (for example, between 0.3 domain 10 bar, particularly between 1.5 and 3.5 bar). In step b), suction is preferably carried out with negative pressure (for example, between 10 and 500 millibars, particularly between 50 and 200 millibars). Utilizing this arrangement, particularly effective and timely production of coated substrates can be achieved.

[0059] Preferably, the method is carried out in an automated manner and with high throughput, preferably in a continuous process in predetermined quantities. In an automated method, the coating medium is applied in step (a) at high speed, for example in a time period between 200 μs and 6 s, in particular between 500 μs and 3 s. Preferably, the suction in step (b) occurs in a time period between 10 μs and 10 s, in particular between 20 μs and 2.5 s.

[0060] In the method according to the invention, a particularly uniform coating of the fine channels of the catalyst support can advantageously be achieved. Due to the particularly uniform penetration depth of the coating medium in the catalyst substrate, the method is particularly suitable for automated production in which a large number of substrates are coated in rapid succession.

[0061] In a preferred embodiment, the method is used to apply two or more coatings to the same substrate, usually in a defined sub-zone (region) of different catalytic effects. In the prior art, it is particularly complicated to provide a catalyst substrate with multiple coatings in a sub-zone. Special attention must be paid to ensure that these regions are relatively clearly positioned. Since the penetration depth can be accurately controlled using the method according to the present invention, this method is particularly suitable for applying and combining regions. For example, the catalyst substrate can be provided with a region of the first coating medium from one side, and the penetration depth is, for example, 10 to 90% of the channel length, and then the second coating medium is applied to the second region from the other side of the catalyst substrate, and the penetration depth is, for example, also 10 to 90% of the channel length. This region can be applied in different zones of the substrate and / or one on another, so as to optimize a specific catalytic reaction.

[0062] The subject of the present invention also includes a kind of applicator system for coating substrate with coating medium, and this applicator system comprises applicator according to the present invention and control unit, and a predetermined amount of coating medium can be discharged from applicator by this control unit.Control unit can preferably be arranged to discharge the coating medium of same predetermined amount repeatedly.Preferably, this system comprises the member for metering, such as tank, supply line and valve.Therefore, a series of similar substrates can be coated in the same way in the automation process.For example, the predetermined amount of coating medium is selected and set according to the size of substrate and passage and desired coating.For example, this predetermined amount is between 20ml and 5000ml, particularly between 60ml and 1500ml, particularly preferably between 120ml and 800ml.The applicator system can contain other common members, such as tank, piston pump, valve and monitoring unit for coating medium so that monitoring process.

[0063] The subject matter of the invention also includes a device for coating a substrate with a coating medium, comprising

[0064] (i) an applicator and / or an applicator system according to the invention,

[0065] (ii) means for securing the substrate beneath the applicator,

[0066] (iii) a zone above the fixed substrate for introducing the coating medium from the applicator, and

[0067] (iv) Means for drawing the coating medium into the substrate.

[0068] The coating method described above can be performed with this device. The member for fixing the substrate is preferably a bracket, in which the substrate can be received, fixed and removed again after coating, preferably in an automated process. After the substrate is fixed, a region (iii) can be temporarily formed, for example, by attaching the housing to the upper edge of the substrate, and the outer body prevents the coating medium from flowing out toward the side. The member for suction can be a vacuum pump, which is connected to the substrate from below via a pipeline. The device can preferably coat multiple substrates one by one in an automatic manner, without external intervention in the process.

[0069] The subject matter of the present invention also includes the use of an applicator, an applicator system and / or a device according to the invention for producing substrate monoliths with a catalytically active coating for automobile exhaust gas aftertreatment.

[0070] The subject matter of the present invention also includes the use of an applicator, an applicator system and / or a device according to the invention for increasing the uniformity of a coating in a substrate monolith.

[0071] In the mentioned methods and uses, preferably an applicator of the invention is used, as described above.

[0072] Figures 1 to 8 Embodiments of the invention are shown schematically and by way of example, as well as objects according to the prior art for comparison.

[0073] Figure 1 A cross section through a device according to the invention for coating a substrate by means of an applicator is shown schematically and by way of example.

[0074] Figure 2 A side view from below of an end plate of an applicator according to the invention is shown schematically and by way of example.

[0075] Figure 3 A cross section through an end plate with laterally inclined nozzles is shown.

[0076] Figure 4 Shown according to Figure 2 Vertical view of the discharge side of the end plate.

[0077] Figure 5 Shown according to Figure 4 A vertical view showing the concentric circles of the nozzle and the radial direction of the plate.

[0078] Figure 6 A detail view of a cross section of an end plate with laterally inclined nozzles and vertical nozzles and a jet of coating medium impinging on a substrate is shown.

[0079] Figure 7 is a photograph of a cross section of a catalyst support which has been coated in a conventional manner with an end plate having vertical nozzles.

[0080] Figure 8 is a photograph of a catalyst support body coated according to the invention, which has been coated according to the invention with an end plate with an inclined nozzle. Figure 7 Direct comparison.

[0081] Hereinafter, exemplary embodiments of the present invention and objects according to the related art for comparison are explained with reference to the accompanying drawings.

[0082] Figure 1A cross section of an apparatus for coating a substrate 2 by an applicator 1 according to the present invention is shown schematically and by way of example. The substrate 2 to be coated is fixed with a member 15 (such as a bracket) for the coating process. The coating medium is metered onto the end face of the substrate 2, which is a catalyst carrier having a plurality of parallel fine channels 14. A type of collar 11 is placed / inserted around the end face and prevents the coating medium from flowing out from the end face and the sides of the substrate 2. The end face of the substrate 2 and the collar 11 define a zone 10 into which the coating medium is introduced before the substrate 2 is coated. The coating medium is first supplied to the cavity 6 above the end plate 9 via a supply line 4. The end plate 9 includes a plurality of laterally inclined nozzles 5. Through the nozzles, the coating medium is introduced from the cavity 6 into the zone 10 above the substrate 2. The precise amount of coating medium required for coating a specific substrate is introduced. After the coating medium is introduced, a negative pressure is applied below the substrate 2 by a member 13 such as a pump, thereby sucking the coating medium from above into the parallel channels 14. The amount, thickness and penetration depth of the coating medium can be controlled in particular via the amount and viscosity of the coating medium, the structure of the substrate 2 and the negative pressure. The method can be adjusted so that the coating penetrates into the channel 14 up to the zone boundary 16. The coating medium can be introduced to the zone boundary 16. This means that the method is controlled so that the coating medium is applied only above the zone boundary 16, so that the catalyst support 1 is coated only on one side. The zone boundary 16 is shown as a line, thus showing an ideal route. In practice, the zone boundary is irregular. With the aid of the applicator 1 according to the invention, the uniformity can be significantly improved (see Figure 7 and Figure 8 ).

[0083] Figure 2 , Figure 3 and Figure 5 An applicator 1 according to the invention is shown schematically and by way of example, having an end plate 9 with a plurality of laterally inclined nozzles 5 . Figure 2 A side elevation view of the applicator 1 is shown, Figure 4 A vertical bottom view is shown, and Figure 5 Shown according to Figure 4 , with the concentric circles and radial directions of the nozzles pointing outward from the center of the plate. The end plate 9 is circular, which allows the nozzles 5 to be arranged in concentric circles at uniform distances. The inclination of the nozzles 5 in the concentric circles is only lateral and tangential, as in Figure 5. This means that the nozzles 5 in the concentric circles are not tilted inwards or outwards in the indicated radial direction. This allows the coating medium to be applied uniformly. The nozzles 5 have a regular arrangement and are at equal distances from each other. This allows the coating medium to be discharged uniformly into the zone 10 above the substrate. The nozzles 5 in each concentric circle are substantially tilted toward the adjacent nozzles. This achieves a regular discharge pattern. Additionally, the jet of the coating medium from the nozzle 5 is prevented from vertically impinging on the substrate and from undesirably penetrating into the channel before the negative pressure is applied. Figures 2 to 5 The nozzle in has a connection piece 12 protruding from the end plate. Figure 3 A cross section through an end plate 9 with a laterally inclined nozzle 5 with a connection piece 12 is shown.

[0084] Figure 6 It is shown schematically and by way of example how the coating medium 3 is discharged from the laterally inclined nozzle 7 and, for comparison, from the vertical nozzle 8 into the region 10 above the substrate 2. An oblique jet is generated from the laterally inclined nozzle 7, which weakens the effect of the impingement on the upwardly open thin channel 14 of the substrate 2. In this way, an undesired penetration of the coating medium 3 into the channel 14 before suction can be prevented or at least significantly reduced, resulting in a more uniform coating.

[0085] Figure 7 and Figure 8 A photograph of a cross section of a coated catalyst support is shown and illustrates the advantages of the invention. Figure 7 A cross section of a coated catalyst support according to the prior art is shown, which is produced by means of an applicator with an outlet plate with a vertical nozzle. The upper coated area is dark and the lower uncoated area is light. The coating penetrates irregularly into the channels. Considerable random fluctuations across a large range can be seen. Particularly noticeable are smaller areas in which the coating medium unexpectedly penetrates into relatively deep channels. Figure 8 A cross section of a catalyst support coated according to the invention is shown. Support and resolution Figure 7 Corresponding, so that the products are comparable. Figure 8 In the figure, it can be seen that the area boundary between the dark coated area and the light uncoated area is uniform and straight. Figure 7 It should be noted that the slightly darker shading of some parts below the zone boundaries is caused by shadowing and not by the coating medium that has penetrated. Figure 8 The loose components visible in the are caused by the cracking process and are also not considered for comparison of the coatings. Figure 7 and Figure 8A comparison of shows that a significant improvement in the coating uniformity can be achieved with the aid of an applicator according to the invention having a laterally inclined nozzle.

[0086] The applicator, applicator system, device, method and use according to the present invention achieve the basic purpose of the present invention. According to the present invention, substrates, such as catalyst carriers for exhaust gas purification devices, can be coated with high precision. This can be achieved by simple design measures, so that the method can be carried out in an effective and timely manner and with high production on an industrial scale. In particular, fine channels of catalyst carriers for exhaust gas purification devices can be coated with high precision, wherein clearly defined areas can be obtained. This makes it possible to significantly save expensive catalytic materials, in particular precious metals or rare earths, and to provide particularly powerful exhaust gas purification devices and further catalytic devices.

[0087] List of reference numerals:

[0088] 1 Applicator

[0089] 2 Substrate to be coated

[0090] 3 Coating medium

[0091] 4 Supply area within the applicator (1)

[0092] 5 Nozzle in end plate (9)

[0093] 6 Cavity in the applicator (1)

[0094] 7 Tilt nozzle

[0095] 8 straight nozzle

[0096] 9 End plate

[0097] 10 Area above the base

[0098] 11 Ring defining the area (10)

[0099] 12 Connectors

[0100] 13 Components for sucking in coating media

[0101] 14 Parallel channels in the substrate (2)

[0102] 15 Member for fixing the base

[0103] 16 Regional boundaries

Claims

1. An applicator (1) for coating a substrate (2) with a coating medium (3), wherein the applicator (1) has at least one supply line (4) for the coating medium, an end plate (9) having at least one nozzle (5) for applying the coating medium to the substrate (2), and a cavity (6) in which the coating medium can be distributed before being applied to the substrate (2), Features At least one nozzle (5) is laterally inclined.

2. The applicator (1) according to claim 1, characterized in that The inclination angle of the laterally inclined nozzle is 2° to 50°, preferably 15° to 30°.

3. Applicator (1) according to at least one of the preceding claims, characterized in that The end plate (9) has a circular or oval cross section.

4. Applicator (1) according to claim 3, characterized in that The at least one nozzle (5) is not substantially inclined inwardly or outwardly in a radial direction.

5. Applicator (1) according to at least one of the preceding claims, characterized in that The nozzles are arranged at a uniform distance from each other.

6. Applicator (1) according to at least one of the preceding claims, characterized in that The end plate (9) comprises a plurality of laterally inclined nozzles and a central nozzle.

7. Applicator (1) according to at least one of the preceding claims, characterized in that The laterally inclined nozzles (5) are arranged in concentric circles around the central nozzle.

8. Applicator (1) according to claim 7, characterized in that The nozzles (5) in each concentric circle are aligned and / or tilted in the same way.

9. Applicator (1) according to at least one of the preceding claims, characterized in that The nozzles (5) are arranged in a spiral shape.

10. Applicator (1) according to at least one of the preceding claims, characterized in that A baffle in the chamber (6) blocks the coating medium (3) from flowing from the supply line (4) to the at least one nozzle (5) in an unpressurized state, and allows the coating medium (3) to flow from the supply line (4) to the at least one nozzle (5) when the coating medium (3) exerts pressure on the baffle.

11. An applicator system for coating a substrate (2) with a coating medium (3), comprising an applicator (1) according to at least one of the preceding claims and a control unit which can be configured to discharge a predetermined amount of coating medium (3) from the applicator (1).

12. A device for coating a substrate (2) with a coating medium (3), comprising (i) An applicator (1) and / or an applicator system according to at least one of the preceding claims, (ii) means for fixing the substrate (2) below the applicator (1), (iii) a zone (10) above the fixed substrate (2) for introducing the coating medium (3) from the applicator (1), and (iv) means for sucking the coating medium (3) into the substrate (2).

13. A method for coating a substrate with a coating medium by means of an applicator (1), an applicator system and / or a device according to at least one of the preceding claims, comprising the following steps: (a) applying the coating medium (3) to the substrate (2) through the nozzle (5) of the end plate (9), and (b) Absorbing the coating medium (3) into the substrate (2).

14. Use of an applicator (1), an applicator system and / or a device according to one of claims 1 to 12 for producing substrate monoliths with a catalytically active coating for automobile exhaust gas aftertreatment.

Images