EP2836312B1 - Assembly and method for compressed air controlled application of a porous coating material to a substrate - Google Patents

Description

The present invention relates to a system and a method for applying a liquid to pasty and porous coating material to a substrate, in particular by means of compressed air-controlled spraying of the coating material, as well as a part of the system which serves to control the promotion of the coating material so that its porosity making Properties are preserved. Furthermore, the present invention relates to the use of a porous coating material for spray application to a substrate.

In the prior art, liquid to pasty coating materials are known which contain highly porous solid particles which are based, for example, on aerogels or xerogels based on silica (silica). In addition, such coating materials may additionally contain gas bubbles which produce a foam-like structure. Such solid particles can be obtained by known sol-gel methods and special drying methods and are available commercially and industrially. Due to their large pore volumes of up to more than 90%, they are interesting as insulating materials, in particular for heat, cold or sound insulation. Liquid to pasty coating materials of the aforementioned type are also referred to below as porous coating materials.

For this purpose, the surfaces to be insulated are coated with the materials, so that the desired insulating effect is achieved, for. B. for roofs, exterior and interior walls of buildings or containers such as containers, tanks, pipelines, Vehicle parts, ship components, plant components of the chemical industry and other industries.

The application of coating materials is generally done by rolling, trowelling or spraying. In the latter method, the coating material is generally supplied from a reservoir via a suitable conduit to a spraying apparatus such as a spray gun, by means of which it is then applied to one or more surfaces (substrate) of an article.

When using porous coating materials, it has proved to be disadvantageous that the pressures occurring in the conveying of the material in installations which are suitable for the injection-molding of liquid to pasty materials on substrates according to the prior art, are so high that the porous and / or foam-like structure is impaired or even completely destroyed. This is accompanied by a corresponding loss of insulation performance. In addition, porous coating materials can not be adequately sprayed in systems which are suitable for the spray-applied application of liquid to pasty materials on substrates according to the prior art. The delivery rate is minimal and it comes after a short period of operation to blockages.

Thus, when using common pump sets for conveying a coating material from a reservoir to the inlet of a spray gun pressures in the range of 10 to about 180 bar occur, regardless of the pump type used such as pistons, diaphragm, centrifugal, worm, gear or Perestaltikpumpen ,

Furthermore, pressure vessel (pressure vessel) as a reservoir and for the promotion of coating material for an injection molding Application known. In this form of material conveyance, the coating material is filled into a container and pressurized with compressed air upon closure, thereby delivering material through an outlet from the container to a conduit connected thereto and devices connected thereto for processing and application of the material to substrates. It proves to be disadvantageous that forms a funnel or V-shaped space in the pressure vessel after pressurization, whereby the coating material is pressed against the container walls, which is associated with an undesirable compression and damage to the porous structure. In addition, the formation of the funnel or V-shaped space prevents the promotion of the coating material.

To avoid this disadvantage, the pressure vessel may be provided with a so-called pressure plate, also called a follower plate, which divides the container into a pressure medium space and a material space. In order to convey the coating material from the material space, the pressure medium space is pressurized and the pressure plate then presses the coating material uniformly in the direction of the outlet. However, in this variant too high pressures occur so that the porous structure is compressed, impaired or destroyed.

So far, therefore, the use of insulating materials of the aforementioned type was relatively limited or associated with the less efficient application methods of trowelling or rolling.

That's how it describes DE 20 2007 017 944 U1 a plastering machine with a pipeline for conveying the plastering material by means of a pump. In addition, the system has a compressed air circuit on. This serves to control valves on a spray lance and in the conveying line for the plastering material.

The DE 102 11 331 A1 describes a mechanically applicable sound or heat insulation and a method for applying the same. In the context of the task underlying the invention of this patent application, the creation of a sprayable thermal insulation is mentioned. It can be used as insulating filler airgel. The airgel can be conveyed in dry form by means of propellant air from a conveyor via a transport hose in the form of a so-called thin stream to a spraying device, which is located directly in front of a surface to be coated (application surface). Immediately before the spray nozzle of the spray device is a mixer in which the dry airgel mixed with binder and moved in a so-called dense stream on to the spray nozzle and the mixture is then applied under pressure from directly to the spray nozzle supplied compressed air to the application surface. Furthermore, it is mentioned that a ready-processed, airgel-containing insulation material can be provided in containers and processed from the container by machine or by hand, without, however, disclosing details regarding a method or a device therefor.

The DE 39 16 319 A1 relates to a spray head on a plastering machine for processing mortar. The mortar is conveyed by means of a mortar pump. The spray head has an air supply, is supplied via the compressed air in the mouth region of the spray head before leakage of the mortar.

US 4,117,551 relates to a spray gun for applying urethane foam. The individual components of the foam are supplied separately from storage containers of the spray gun and mixed within the spray gun and from there to a Substrate applied as a foam. The structure of the spray gun is particularly in the FIGS. 2 to 6 shown.

In view of the above background, it is an object of the present invention to provide a plant and a process which incorporates materials containing porous solids formed from airgel or xerogel particles of organic or inorganic materials, such as, in particular, aerogels and xerogels Of silica, can be applied efficiently to a variety of different substrates, without losing the decisive for the insulating effect porosity of the coating materials.

1. a) mindestens ein Druckbehälter über einen Einlass mit Beschichtungsmaterial beschickt wird, das poröse Festkörperteilchen enthält, die aus Aerogel- oder Xerogelteilchen aus organischen oder anorganischen Materialien gebildet sind,
2. b) das Beschichtungsmaterial durch einen Auslass des mindestens einen Druckbehälters in eine Leitung befördert wird, an die eine Spritzapparatur angeschlossen ist,
3. c) wobei das Beschichtungsmaterial durch eine Ventileinheit geleitet wird, die stromabwärts des mindestens einen Druckbehälters und stromaufwärts der Spritzapparatur angeordnet ist und in der das Beschichtungsmaterial mit Druckluft und gegebenenfalls Wasser oder wasserhaltigen Zusätzen vermischt wird,
4. d) das so behandelte Beschichtungsmaterial in einen Einlass der Spritzapparatur geleitet wird,
5. e) der Spritzapparatur über einen weiteren Einlass Druckluft zugeführt wird und
6. f) das Beschichtungsmaterial druckluftunterstützt zerstäubt und auf ein Substrat aufgebracht wird.

The object according to the invention is achieved by a system and a method for compressed air-controlled application of a porous coating material to a substrate, in which

1. a) charging at least one pressure vessel via an inlet with coating material containing porous solid particles formed from airgel or xerogel particles of organic or inorganic materials,
2. b) the coating material is conveyed through an outlet of the at least one pressure vessel into a conduit to which a spraying apparatus is connected,
3. c) wherein the coating material is passed through a valve unit which is arranged downstream of the at least one pressure vessel and upstream of the injection apparatus and in which the coating material is mixed with compressed air and optionally water or aqueous additives,
4. d) the coating material treated in this way is passed into an inlet of the injection apparatus,
5. e) the compressed air is supplied to the injection apparatus via a further inlet and
6. f) the coating material is atomized with compressed air and applied to a substrate.

• mindestens eine in Längsrichtung durch die Ventileinheit verlaufende Bohrung aufweist, die einen Durchlasskanal zum Transport des Beschichtungsmaterials bildet,
• mindestens eine seitliche Bohrung aufweist, die einen Einlass für die Zufuhr von Druckluft bildet, die gegebenenfalls mit Wasser oder wasserhaltigen Zusätzen versetzt ist, wobei die mindestens eine seitliche Bohrung mit der in Längsrichtung verlaufenden Bohrung so verbunden ist,
• dass das Beschichtungsmaterial im Durchlasskanal mit der Druckluft vermischt werden kann, wobei die seitlichen Bohrungen jeweils mit Rückschlagventilen versehen sind.

The inventive plant for compressed air controlled application of coating material containing porous solid particles, which are formed from airgel or xerogel particles of organic or inorganic materials, comprises on a substrate
at least one pressure vessel for charging with coating material, the pressure vessel having an inlet and an outlet for the coating material,
a spray apparatus for applying the porous coating material to a substrate, the injection apparatus having an inlet for the coating material, a further inlet for the supply of compressed air and a nozzle arrangement,
a conduit connecting the coating material outlet of the pressure vessel with the coating material inlet of the spraying apparatus,
a valve unit which is connected to the conduit and which is arranged downstream of the outlet of the pressure vessel and upstream of the inlet of the injection apparatus, wherein the valve unit

• has at least one longitudinally extending through the valve unit bore which forms a passageway for transporting the coating material,
• has at least one lateral bore forming an inlet for the supply of compressed air, optionally mixed with water or water-containing additives, the at least one lateral bore being connected to the longitudinal bore,
• that the coating material can be mixed in the passage with the compressed air, the lateral bores are each provided with check valves.

Another object of the invention is the use of a valve unit for controlling the delivery of a coating material containing porous solid particles formed from airgel or xerogel particles of organic or inorganic materials, the valve unit
has at least one longitudinally extending through the valve unit bore which forms a passageway for transporting the coating material,
has at least one lateral bore which forms an inlet for the supply of compressed air, which is optionally mixed with water or aqueous additives, wherein the at least one lateral bore is connected to the longitudinal bore such that the coating material in the passageway with the compressed air can be mixed, and
optionally has at least one further lateral bore which forms an inlet for water for cleaning purposes and which is also connected to the longitudinal bore, wherein the lateral bores are each provided with check valves.

Further, the invention relates to the use of a coating material as defined herein for spray application to a substrate as defined herein.

Finally, the invention relates to a method for the isolation of an article, in which as substrate one or more surfaces of the object to be insulated are coated by the method according to the invention as defined herein.

Preferred embodiments of the invention are disclosed in the following description, the figures and the dependent claims.

In certain embodiments, the method according to the invention and the system according to the invention comprise further features in addition to the features mentioned in the patent claims. In further embodiments, the method and the system according to the invention consist of the features disclosed in the patent claims and the present description. The same applies mutatis mutandis to the part of the system according to the invention, which serves to control the promotion of the coating material.

In particular, the system according to the invention does not comprise pumps for conveying the coating material. Instead, as disclosed above and also below, the porous coating material is conveyed by means of compressed air. It is in the valve unit according to the invention, which can also be referred to as a mixing unit, mixed with compressed air and, if necessary, water or water-containing additives. Thus, the porous structure of the coating material can be obtained.

Compared to the aforementioned prior art, the present invention is thus characterized in particular by the advantage that no pumps are used to convey the coating material. Instead, the coating material is conveyed with compressed air and, in particular, in the valve or mixing unit according to the invention with compressed air and, if necessary, water / water-containing Mixed additives before then the coating material is supported by compressed air applied by means of a spraying apparatus on a surface to be coated.

Brief description of the figures

• FIG. 1 shows an overall view of the system according to the invention.
• FIG. 2 shows a pressure vessel according to the invention with pressure plate, outlet and exhaust valve.
• FIG. 3 shows a valve unit according to the invention with passage channel for the coating material and lateral feeds for compressed air.
• FIG. 4 shows a side view of a spraying apparatus in the form of a handgun.
• FIG. 5 shows a sectional view of the handgun.
• FIG. 6 shows a front view, a side view and a top view of a system according to the invention, which is arranged on a trolley, and a picture of an operator with the system for illustrating a possible dimensioning.
• FIG. 7 shows a three-dimensional view of a system according to the invention with two pressure vessels, which is arranged on a trolley.

However, the invention is not limited to the embodiments shown in the above figures.

FIG. 1 shows an overall view of the system according to the invention, a pressure vessel 1 , a spraying apparatus 2 , a valve unit according to the invention 3 , a Druckregelventil- and Druckmesseinrichtungsanordnung (manometer) 5 for the regulation of compressed air supply and the corresponding lines 4a , 4b , 6, 7, 8 for compressed air - and coating material promotion includes. Not shown in FIG. 1 is another container for receiving liquid, especially water or water-containing liquids, and a conduit with which the container is connected to the compressed air line 7 , so that the compressed air supplied in the valve unit 3 can be moistened as required.

In step (a) of the method according to the invention, the pressure vessel 1 is charged via an inlet with porous coating material. The inlet can be formed, for example, by a removable lid of the container, which is closed again after being charged to the container with this pressure. Alternatively, the inlet may be in the form of an opening at a suitable location on the container provided with a suitable valve connected to a conduit through which coating material is supplied.

After charging the pressure vessel 1 , the coating material according to step (b) of the method according to the invention by pressurization via the outlet 1 d (see FIG. 2 ), which is provided with a valve for opening and closing the outlet, is conveyed from the container into the conduit ( 4a, 4b ) to which a spraying apparatus 2 is connected.

If an embodiment is used in the pressure vessel, the pressure plate 9 (see FIG. 2 ) , the pressure vessel is divided into a coating material space 1e and a pressure medium space 1f . By applying the pressure medium space With compressed air supplied via line 6 , this is set in motion, so that the coating material from the coating material space 1e in line 4a , 4b is conveyed. Alternatively, the pressure plate can be moved mechanically or hydraulically.

According to the invention more than one pressure vessel can be used and can be removed from this simultaneously or successively coating material. There are then other lines and valves that regulate the simultaneous or successive transport of the coating material from these containers.

After leaving the pressure vessel and entering line 4a , the coating material according to step (c) of the method according to the invention is passed through a valve unit 3 according to the invention. The valve unit has a longitudinal bore which forms a passageway 3a for the coating material. This is connected to lateral bores 3b and 3c , which form inlets for compressed air, so that the coating material is mixed in the passageway with the compressed air and swirled by them. The inlets are provided with check valves 3e, 3f .

The compressed air is optionally a liquid, in particular water or water-containing materials, added and optionally further additives to be added to the coating material and the compressed air can be transported. For this, a suitable nebulizer (not shown in FIG. 1 ) can be used.

By taking place in the valve unit 3 compressed air supply the coating material is loosened in the further promotion by line 4b to the spray apparatus such that damage or destruction of the porous structure or the components constituting the porous structure of the coating material are avoided or sufficiently reduced, so that the material is suitable as an insulating material after being applied to a substrate.

In the light of this disclosure, those skilled in the art will recognize, with respect to the length of leads 4a and 4b , that they are to be designed to achieve the above effect. Of course, the exact lengths depend on the overall dimensions of the system according to the invention. As well as in FIG. 1 illustrated, the valve unit 3 according to the invention can connect via a short line section 4a or directly to the pressure vessel.

After mixing and, if appropriate, moistening or addition of further materials which can be conveyed by means of compressed air in the valve unit 3 , the coating material is further conveyed by compressed air through line 4b to the injection apparatus. The line 4a, 4b may be wholly or partly formed of rigid or flexible pressure-resistant material.

For example, the conduit 4a may be made of stainless steel and the conduit 4b of a pressure-resistant flexible hose based on, for example, polyvinyl chloride. Furthermore, hoses based on mixtures of PVC and silicone are suitable, which are in particular double-walled. The tube materials are characterized in that they are smooth-walled and absorb moisture.

For example, for the downstream of the valve unit arranged line 4b , a commercially available from the company Petzetakis Germany GmbH flexible hose based on PVC with the trade name Helivyl Buna Super Soft is used, which can be used over a temperature range of -30 ° C to + 80 ° C. and required resistance to weathering (ozone and UV, water, acids, alkalis, aging resistance). Exemplary hose lengths are 1 to 50 m, preferably 10 to 40 m, z. B. 12 or 15 to 20 m.

The inner diameter of the lines of the system according to the invention can be in the range of a few mm to cm, depending on the overall dimensioning of the system. For the conduit 4a , 4b for conveying the coating material, the inner diameter is, for example, 10 to 20 mm. In particular, a tube of the above type can be used, wherein the inner diameter is 13 mm.

Cables used for compressed air supply have diameters within the same order of magnitude as described above. In particular, a line 8 for supplying compressed air to the injection apparatus from a conduit such as a hose having an inner diameter in the range of 5 to 20 mm, in particular 5 to 15 mm such as 9 mm exist.

In step (d) of the method according to the invention, the coating material is conducted into an inlet of a spraying apparatus 2 , which can be designed, for example, as a manual or automatic spray gun with a nozzle arrangement 2a , an actuating lever 2b and a pistol grip 2c . The injection apparatus has a further inlet 2d for the supply of compressed air.

In the injection apparatus, the compressed air is then brought into contact with the coating material in such a way that it can be atomized via the nozzle arrangement 2a and applied to the substrate to be coated in a suitable jet such as a flat jet or an omnidirectional jet.

By the pressure control valve and pressure gauge 5 , the pressures in the pressure vessel 1 , in the coating material line 4a , 4b and in the compressed air lines 7 to the valve unit and 8 to the injection apparatus separately controllable, so that in each case the desired operating conditions can be adjusted.

In the method according to the invention, the working pressures in the pressure vessel are generally in the range between 2 and 5 bar, in particular 2 to 4.5 bar, in the valve unit according to the invention in the range between 2 and 4 bar, in particular 2 to 3 bar, and in the injection apparatus in Range from 2 to 5 bar.

Depending on the viscosity of the coating material according to one embodiment of the invention, the working pressure in the pressure vessel and the pressure for the additional compressed air supply in the valve unit according to the invention between 1.5 and 3.0 bar, the pressure for the additional compressed air supply equal to or lower than the working pressure in Pressure vessel is.

The flow rate of the coating material is generally 0.25 to 10 kg / min., Which value depends on the pressures used in the individual plant areas and the dimensioning of the nozzle arrangement in the spraying apparatus.

When adding liquid for humidifying the compressed air, in particular water or water-containing liquid, in the compressed air supplied via a line 7 of the valve unit 3 , the liquid consumption in the above conditions is about 0.05 to 1 kg / hour, this value also from the Dimensioning of the system and the pressures used in the individual plant areas and the nozzle assembly depends.

The following two tables give typical compressed air consumption (in 1 / min) in spray gun type spraying equipment depending on the nozzle size used in the injection apparatus and the set pressure. Nozzle Ø mm Pressure in bar 2 bar 3 bar 4 bar 5 bar 6 bar 3.0 300 380 470 570 700 4.0 450 570 700 840 1000 5.0 640 840 1050 1270 1500 6.0 920 1250 1600 1950 2200 Nozzle Ø print 6mm 9mm 12 mm 3 bar 510 650 800 4 bar 530 670 825 5 bar 530 700 860

However, the above values are also dependent on the ambient temperature and the properties of the coating material and may vary depending thereon.

The process according to the invention is generally carried out at room temperature, i. H. carried out in a temperature range between 15 and 25 ° C. However, it may also be carried out at lower or higher temperatures as long as the conveyance of the coating material is given, e.g. in a temperature range of 5 to 15 ° C.

FIG. 2 shows an embodiment of the pressure vessel according to the invention with pressure plate 9 and outlet 1d, which leads into a coating material line 4a , which is connected to a valve 1b for controlling the outflow from the pressure vessel 1 . By using the pressure plate 9 , the pressure vessel is subdivided into a coating material space 1e and a pressure medium space 1f . By pressurizing the Pressure medium space 1f , the pressure plate is moved towards the outlet and so the coating material in line 4a transported.

FIG. 3 shows an enlarged view of an embodiment of the valve unit according to the invention, which is connected upstream via the valve 1b to a line 4a , in which the coating material from the outlet of the pressure vessel occurs. On the downstream side, the valve unit is connected to a conduit 4b leading to the injection apparatus. The valve unit has a passage 3 a , which is laterally connected to bores 3 b and 3 c , which are provided on their outer side respectively with check valves 3 e and 3 f , are connected to the lines 7 a and 7 b , takes place via the compressed air supply. In this case, the compressed air with liquid, especially water, water-containing materials or other additives, which are conveyed by compressed air, are added.

The lateral bores 3b and 3c are arranged so that the supply of compressed air, the promotion of the material downstream of the injection apparatus supports. For this purpose, the holes are arranged in particular at an angle <90 °, preferably at an angle in the range of 20 to 60 °, in particular 30 to 50 °, such as 35 to 45 °. Preferably, the lateral bores are arranged opposite one another. As a result, a particularly favorable mixing and loosening of the material is achieved.

Not shown in FIG. 3 is another connection that can be mounted on the top of the valve unit and the supply of detergent and / or water after the end of the operation of the system according to the invention, so that it can be cleaned and freed from coating material residues. This further supply line is also provided with a suitable valve such as a check valve.

FIG. 4 shows a side view of a spray gun in the form of a handgun, which is equipped with a nozzle assembly 2a , an actuating lever 2b, an inlet for the coating material 2c and another inlet for compressed air 2d . The handgun also has a suspension hook 2f .

FIG. 5 shows a side sectional view of the handgun after FIG. 4 , According to the invention, the atomization is carried out, for example, by means of commercially available spray guns known to the person skilled in the art, which have suitable nozzle arrangements with internal and external atomization.

FIG. 6 shows an embodiment of the system according to the invention, in which it is arranged on a trolley. A suitable embodiment of the trolley has a width 10 of 70 to 100 cm, a height 11 of 70 to 100 cm and a length 12 of 80 to 100 cm. On the bottom plate of the trolley, a housing is applied, within which the valve unit 3 according to the invention is housed. On the top of the housing, there are two pressure vessels, each having an outlet with adjoining material conduit, which are merged into a conduit connected to the valve unit (not shown in FIG FIG. 6 ).

In the front view of FIG. 6a a connection 14 can be seen, to which a line 4 for conveying the coating material can be connected to a spraying apparatus. Line 4 is in the in FIG. 6 shown embodiment designed as a flexible hose, which is shown in its storage position. Further, a container 15 is arranged on the trolley, in which a liquid such as water is stored for humidifying the compressed air and the to a compressed air line 7 (not shown in FIG FIG. 6 ) , which leads to the valve unit according to the invention.

In addition to a mobile embodiment, as shown for example in FIG. 6 , the installation according to the invention can also be designed to be stationary, ie permanently at a specific location.

In FIG. 7 is a three-dimensional view of the trolley according to FIG. 6 shown in particular inlet valves for the compressed air supply to the pressure vessels 1 are shown. The pressure vessels 1 have on their upper side also via pressure gauges, which indicate the pressure in the pressure medium space. Otherwise, the explanations to FIG. 6 to get expelled.

The equipment according to the invention has been described above with respect to its use for the application of a porous coating material. However, the system and in particular the arrangement of the valve unit according to the invention can also be used for other purposes in which a material delivery and compressed air supply are beneficial, as the plant of the invention allows. Thus, if desired, the system can also be used to apply non-porous materials to substrates or to treat surfaces with materials which can be conveyed and applied by the system according to the invention, even if no lasting connection between the material and the treated substrate is associated with the application. z. B. because there is only a cleaning or polishing effect to be achieved.

According to the invention, in addition to conventional compressed air, other gases and gas mixtures (compressed gases) for pressurizing and pressure-assisted transport and application can be used.

Porous coating materials which can be conveyed with the system according to the invention and applied to substrates, as well as their preparation are described, for example, in US Pat EP 1 697 671 A1 and the WO 2003/097227 A1 described. Other suitable materials are commercially available, e.g. From Worlee-Chemie GmbH, Hamburg, Germany.

The porous, liquid to pasty coating materials are generally aqueous dispersions of porous, i. Pore-containing solid particles before. In other words, a coating material according to the invention comprises a liquid phase in which porous solid particles dispersed in airgel or xerogel particles of organic or inorganic materials are dispersed. The consistency of this dispersion can be described as liquid to pasty, depending on the proportions of the solid and liquid components of the respective dispersion. In addition, these coating materials may additionally contain gas bubbles (e.g., air-filled or air-filled gas bubbles) which create a foam-like structure. The materials according to the invention described above are also referred to herein briefly as porous coating materials.

In particular, the coating material according to the invention has a viscosity of 10,000 to 100,000 mPas, in particular 30,000 to 100,000 mPas, preferably 50,000 to 90,000 mPas, measured with a haake VT 500 viscometer, measuring device E 100, shear stress about 91 S ^-1 .

Depending on the desired application, the coating materials, in addition to the constituents that make up the porosity, more solid or liquid ingredients are added to give the desired properties such. B. flame retardants for the flame retardant finishing of an insulating layer or corrosion protection agent prepared from the coating material for anti-corrosive equipment when applied to metal substrates.

The substrates to be coated may form or form part of items such as roofs, exterior and interior walls of buildings or containers such as containers, tanks, pipelines, vehicle parts, marine components, plant components of the chemical industry and other industries. They may have already been coated with other materials prior to applying the coating of the invention, e.g. with paints.

In particular, the substrate comprises or consists of a material selected from the group consisting of glass, wood and wood-based materials, metals, in particular iron, steel and aluminum, in particular anodized aluminum, mineral building materials such as concrete, cement materials, tiles, stones, such as eg Limestone, ytong stone, ceramics, and plastics, in particular polyethylene, and copolymers thereof, and polymers suitable for use as paints, such as alkyd resins, and combinations thereof.

The porous solid particles of the coating material of the invention are formed from airgel or xerogel particles of organic or inorganic materials, e.g. Resorcinol-formaldehyde or melamine-formaldehyde airgel particles or metal oxide airgel particles (e.g., silica, titania and alumina aerogels).

The porous coating material which can be processed according to the invention preferably contains porous solid particles based on silica aerogels or xerogels, which may optionally be chemically modified. In particular, the surface of the aerosols or xerogels is hydrophobically modified, in particular by silanization. In particular, silica-based aerogels are hereafter also short Silica aerogels, suitable according to the invention. These materials have a density in the range of 100 to 140 kg / m ³ and a porosity of> 80%, in particular of> 90%. The porosity is accompanied by a high internal surface area of about 600 to 800 g / m ² , measured as the BET surface area, and a high oil absorption of about 500 to 700 g of DBP (dibutyl phthalate) per 100 g of solid particles.

As is known to those skilled in the art, the porosity or degree of porosity means the percentage of pore volume in the total volume of the porous material. A porous coating material based on silica aerogels or xerogels which can be processed according to the invention preferably has the following parameters, which relate to the material as starting material, ie. H. before application to substrates by the method described herein and subsequent drying to form an insulating layer.

The density of the material is generally 0.3 to 0.8 g / cm ³ , in particular 0.4 to 0.6 g / cm ³ , in particular 0.5 g / cm ³ .

The pH is generally in the range of 7 to 10, preferably 8 to 10, especially 8.3 to 8.5. The Shore hardness (measured with a hardness tester according to DIN 53505) is generally in the range of A = 20 to 70, preferably 30 to 60, in particular 45.

The total solids content, ie the content of the dispersions of porous and non-porous solids, is generally in the range of about 50 to 90 wt .-%, preferably 60 to 80 wt .-%, in particular 65 to 75 wt .-% as about 67% by weight.

The content of porous solid particles is generally in the range of about 8 to 30 wt .-%, preferably 10 to 20 wt .-%, in particular 10 to 15 wt .-%.

The gas bubble content is generally in the range of 0 vol .-% to 50 vol .-%, preferably 10 vol .-% to 40 vol .-%, in particular 20 vol .-% to 30 vol .-%. The gas bubble content is calculated by subtracting from the volume of the total formulation (calculated from mass * density) the volume fraction of the formulation constituents and placing it in relation to the total volume.

The water content of the formulation of the coating material is generally in the range of 20 to 50 wt .-%, preferably 25 to 40 wt .-%, in particular 30 to 35 wt .-% such as 32 wt .-%.

In addition to the porous solid constituent and a dispersant, in particular water, the coating material generally contains as further constituents at least one polymer or copolymer, in particular acrylate-based, and optionally further constituents such as emulsifiers, stabilizers, surfactants, pigments, flame retardant additives, corrosion inhibitors, etc.

The porous coating material is applied by means of the method according to the invention generally in layer thicknesses of up to 30 mm on a substrate. Preferably, the layer thickness is in the range of 10 mm to 100 .mu.m, in particular 5 mm to 500 .mu.m, based on the dried state, which is generally achieved by drying at room temperature within 24 hours after application. It can also be dried at elevated temperatures, eg at temperatures up to 120 ° C. In the not yet dried, ie wet state, the layer thicknesses are usually about 10 to 20% larger.

embodiment

A coating material was prepared according to the following recipe. component amount Chem. Composition 1 WorléeCryl CH-X-2156 61% in water 48,20 acrylate 2 WorléeCryl CH-X 2157 59% in water 24.00 acrylate 3 WorléePaste W 931 (white) 50% in water 1.41 TiO ₂ paste 4 Fiberglass FGCS 316/3 3.29 glass fibers 5 WorléeAdd FR 5000 9.39 Flame retardant based on phosphorus compounds 6 Enova airgel 9.39 Silica airgel 7 WorléeAdd 8905 2.82 Alkaline ZnO solution 8th water 1.5 Σ 100.00

4 is available from STW - Schwarzwälder Textilwerke, the remaining components are available from Worlee Chemie GmbH, Hamburg.

To prepare the coating material, component 1 and component 2 were initially charged and homogenized with stirring. Then, constituent 3 and constituent 4 were slowly interspersed in portions with stirring and then dispersed with the dissolver under high shear. Thereafter, ingredient 5 was slowly interspersed in portions with slow stirring and homogenized using low gravitational forces. Subsequently, constituent 6 was slowly interspersed in portions with slow stirring and homogenized using low gravitational forces. Finally, ingredient 7 and ingredient 8 were allowed to flow in with slow stirring and homogenized using low gravitational forces.

Subsequently, an amount of about 5 kg of the coating material was placed in a pressure vessel of a plant as in FIG. 6 introduced and applied by means of this system to a steel sheet as a substrate.

Before the porous coating material was filled in the system, it was filled with water and rinsed. In addition to the pre-moistening of the pressure vessel 1 and the tubes 4a, 4b, the function of the individual components can be checked in this case.

The container or containers 1 were designed so that they could be filled with 2 liters of water each and then sealed. The containers were pressurized with 0.5 bar. The outlet valve 1b of the pressure vessels and the valve unit 3 according to the invention were opened and the lever 2b of the spray gun 2 was actuated. The water was pushed through the system and exited the gun nozzle.

In addition, the compressed air supply via line 7 was opened, also with 0.5 bar. The water was enriched with air from the nozzle. The atomizing air supply 8 was opened and also set at 0.5 bar. The air-enriched water sputtered out of the nozzle on the gun 2 . This process can serve both the pre-moistening of all relevant parts and the function check. After the container (s) were drained, the pressure was released.

Then, coating material was filled in the pressure vessel 2 . Thereafter, the pressure plate 9 was placed on the material and the container / 2 closed. The material pressure and the compressed air supply 7 were set to 2.5 bar. Thereafter, the exhaust valve 1b was opened and the gun lever 2b was operated. If the material comes out of the nozzle of the gun 2 , the atomizing air was adjusted to 3.0 bar and the material was applied to a substrate.

After completion of the work, the system was rinsed with water as described and cleaned.

Further, suitable specimens were prepared from the coating material and the heat transfer coefficient and the thermal conductivity were measured. To prepare the specimens, the coating material was applied to a non-adhesive surface (eg made of Teflon) (wet about 12 mm layer thickness, dry about 10 mm layer thickness). After drying, the coating was removed from the substrate and square test specimens with 29 cm edge length were cut.

The heat transfer coefficient indicates the amount of heat that passes through 1 m ^{2 of} a substance with a certain layer thickness when the temperature difference is 1 K. This value is thus layer thickness-dependent. It was measured according to the method described in DIN EN 12664. Thereafter, the heat transfer coefficient for a sample coated with a 10 mm thick layer of the above insulating material was 4.7 W / (m ² × K).

The thermal conductivity is the ability of a substance to transport thermal energy by means of heat conduction in the form of heat. As a substance constant, this value is independent of the layer thickness. The thermal conductivity of the sample layer mentioned above was 0.046 W / (m ² × K), measured according to the method described in DIN EN 12664.

LIST OF REFERENCE NUMBERS

1

pressure vessel

1a, 1b

Inlet valve or outlet valve pressure vessel

1c

Upper closure of the pressure vessel

1e

Coating material space

1d

Outlet pressure vessel

1f

Pressure fluid chamber

2

spraying equipment

2a

atomizer

2 B

actuating lever

2c

Spray apparatus handle

2d

Inlet compressed air spray apparatus

2e

Coating material supply Spray apparatus

2f

Grab handle sprayer

3

valve unit

3a

Passage passage valve unit

3b, 3c

lateral bores valve unit

3d, 3e

check valves

4

Line between pressure vessel and spraying equipment

4a, 4b

Downstream or upstream lines

5

Pressure control valve and manometer arrangement for compressed air supply

5a

Pressure control valve and manometer for compressed air supply pressure vessel

5b

Pressure control valve and manometer for compressed air supply Valve unit

5c

Pressure control valve and manometer for compressed air supply Spraying apparatus

6

Compressed air line pressure vessel

7

Compressed air line Valve unit

7a, 7b

Compressed air supply lines Valve unit

8th

Compressed air line spraying device

9

Pressure plate pressure vessel

10

Wide trolley

11

Height trolley

12

Length trolley

13

operator

14

Connection for line 4

15

liquid container

Claims (16)

1. Method for compressed air-controlled application of a porous coating material onto a substrate, characterised in that

   a) at least one pressure vessel is charged through an inlet with coating material that comprises porous solid particles that are formed from aerogel particles or xerogel particles made of organic or inorganic materials,

   b) the coating material is conveyed through an outlet of the at least one pressure vessel into a line that is connected to a spraying apparatus,

   c) wherein the coating material is conducted through a valve unit that is arranged downstream of the at least one pressure vessel and upstream of the spraying apparatus and in which the coating material is mixed with compressed air and optionally water or water-containing additives,

   d) the thus-treated coating material is conducted into an inlet of the spraying apparatus,

   e) the spraying apparatus is supplied with compressed air through a further inlet, and

   f) the coating material is atomised in a compressed air-assisted manner and applied onto a substrate.
2. Method according to claim 1, characterised in that the porosity of the coating material is such that it is suitable for use as an insulating material and the porosity of the coating material is preserved during the procedural steps a) to f).
3. Method according to claim 1 or 2, characterised in that the coating material comprises porous solid particles that exhibit a porosity of > 80 %.
4. Method according to one of the preceding claims, characterised in that the viscosity of the coating material is from 10 000 to 120 000 mPas, measured with a Haake viscometer VT 500, measuring system E 100, shear stress ca. 91 S^-1.
5. Method according to one of the preceding claims, characterised in that the pressure in the pressure vessel and the spray apparatus is from 2 to 5 bar and in the valve unit 2 to 3 bar.
6. Method according to one of the preceding claims, characterised in that the substrate contains or consists of a material that is selected from the group consisting of glass, wood and wood-based materials, metals, mineral building materials as well as plastic and combinations thereof.
7. Method according to one of the preceding claims, characterised in that the thickness of the coating material that is applied onto the substrate is from 50 µm to 30 mm, thereby producing an insulation layer.
8. Equipment for compressed air-controlled application of coating material that comprises porous solid particles that are formed from aerogel particles or xerogel particles made of organic or inorganic materials, characterised in that said equipment possesses
   at least one pressure vessel to be charged with coating material, wherein the pressure vessel possesses an inlet and an outlet for the coating material,
   a spray apparatus for applying the porous coating material onto a substrate, wherein the spray apparatus possesses an inlet for the coating material, a further inlet for the supply of compressed air and a nozzle arrangement,
   a line that connects the coating material outlet of the pressure vessel to the spray apparatus,
   a valve unit that is connected to the line and which is arranged downstream of the outlet of the pressure vessel and upstream of the inlet of the spraying apparatus, wherein the valve unit

   possesses at least one bore running longitudinally through the valve unit which forms a channel passage for transporting the coating material,

   possesses at least one lateral bore that forms an inlet for the supply of compressed air that is optionally transferred with water or water-containing additives, wherein the at least one lateral bore is connected to the longitudinally running bore in such a way that the coating material can be mixed with the compressed air in the channel passage,

   wherein the lateral bores are each equipped with non-return valves.
9. Equipment according to claim 8, characterised in that the line that connects the pressure vessel to the spray apparatus is designed in the form of a flexible tube upstream and/or downstream of the valve unit.
10. Equipment according to claim 9, characterised in that the tube is made of material that comprises polyvinyl chloride.
11. Equipment according to one of claims 8 to 10, characterised in that the valve unit possesses at least one further lateral bore that forms an inlet for water for cleaning purposes, and is likewise connected to the longitudinally running bore.
12. Equipment according to one of claims 8 to 11, characterised in that the valve unit
    possesses two lateral bores that each form inlets for the supply of compressed air, wherein the compressed air is optionally transferred with water or water-containing additives, and the lateral bores are in fluid communication with the longitudinally running bore, wherein both lateral bores are arranged on the right side and left side opposite one another,
    possesses a third lateral bore that forms an inlet for water for cleaning purposes, and which is also in fluid communication with the longitudinally running bore, wherein the third lateral bore is arranged on the upper or lower side.
13. Equipment according to claim 11 or claim 12, characterised in that the at least one or both lateral bores that each form inlets for the supply of compressed air, wherein the compressed air is optionally transferred with water or water-containing additives, said lateral bores being arranged at an acute angle, preferably at an angle between 20 to 60°, particularly 30 to 40°, relative to the upstream part of the longitudinally running bore that forms the channel passage for the coating material.
14. Use of a coating material as defined in one of claims 1 to 4 for the spray technological application onto a substrate according to one of claims 6 to 7 by means of a method as defined in one of claims 1, 2 and 5.
15. Method for insulating an article, characterised in that as the substrate, one or more surfaces of the article to be insulated, are coated according to the method according to one of claims 1 to 7.
16. Use of a valve unit for controlling the flow of a coating material that comprises solid particles formed from aerogel particles or xerogel particles made of organic or inorganic materials, wherein the valve unit is designed as defined in one of claims 8 and 11 to 13.

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