DE102005001714A1 - Production of nanoparticle platelets by PVD involves impacting a low temperature gas onto a multilayered intermediate to cause embrittlement and break up - Google Patents

Abstract

Production of nanoparticle platelets by PVD at better than 1 Pa vacuum of more than 10 layers with alternating separation agent layers comprises: (a) applying as liquid a 5-250 mu meltable organic gloss layer on a carrier turning on its axis; (b) applying the required layers; and (c) feeding a gas at less than -25[deg]C under pressure from one or more nozzles such that the gloss layer is embrittled and the multilayer coating is released as small particles. An independent claim is also included for apparatus for the process comprising a vapor deposition chamber, a side chamber for use in part of stage (c) and a vacuum-tight lock for use in stage (c), the apparatus operating such that a first carrier is introduced into the side chamber while a second carrier is simultaneously subjected to deposition in the vapor deposition chamber.

Description

Platelet-shaped nanoparticles, which can be prepared by the PVD process from various materials such as metals, oxides, fluorides, and multi-layer combinations thereof, are characterized by a precisely controllable thickness and are produced by vapor deposition in a dry vacuum process. The thickness range is between 20 and 1000 nanometers, depending on the application. They serve as a security pigment on banknotes with a layer system consisting of chromium-magnesium fluoride-aluminum-magnesium fluoride-chromium EP 0227423 (R. Phillips)) or in the decorative area as aluminum platelets of about 30 nanometers thickness, with dimensions of about 10 × 10 microns.

For their preparation, numerous PVD methods have been disclosed, such as DE19844357 (Weinert), in which a metal strip circulating under vacuum is steamed with release agent and product layers, which are then peeled off in a zone of 20-50 mbar by water as platelets. The vacuum-dried tape runs back into the evaporation zone. US 6398999 (Josephy et al.) Use vaporized polymers such as polystyrene or acrylates as release agents. The entire layer package is removed from the vacuum chamber, and in a strong solvent, the release agent is dissolved between the layers. After a multi-step washing process with fresh solvents, the nanoplates are available as a suspension. DE 500024920 (J. Weinert) uses a rotating body, on which both alternating layers are vapor-deposited under vacuum, which are then peeled off or melted together. As an alternative, both a release agent and a product layer can be vapor-deposited in one revolution, followed by liquid detachment at a further angle of rotation of the body. US 4168986 (Venis) uses a polyester film as a carrier with likewise vapor-deposited release agent to produce interference layers of TiO 2 -MgF 2 -TiO 2. WO 03068868 (Bujard et al.) Describes the preparation of nanosheets from silicon suboxides with subsequent partial conversion into silicon carbide ., US 3,123,489 (Bolomey) evaporates alternating layers of salts, eg borax and zinc sulfide on a rotating plate. The plate is then removed from the vacuum space and dissolved in water, the intermediate layers of salt, wherein the product layers also disintegrate into small platelets.

Common to the said method is that either a painted plastic film is used as a carrier or a metal-coated with a soluble release agent carrier. For replacement, either organic solvents, such as acetone, toluene or ethyl acetate are used, or, if the vapor-deposited release agent is water-soluble, such as salts and some organic substances, including water. Patents, which cite a number of organic release agents for the production of PVD nanoplates, describe the properties and their application in WO 02/094945 (Weinert) and EP 1273358 (Moosheimer).

Of the common disadvantage of this known method is that in the replacement from the carrier always a wet process must be used. As long as it is a layer composite consisting of only a single layer Separation layer and a product layer, the replacement is easy and fast possible. Such wet process fail when layers of hundreds of layers of vapor deposited on one another and Product layers exist, are exposed. The solvent must be successively each dissolve a release agent layer before the liquid can get to the lower lying. Such layer packages but are of great economic interest, since this makes it possible, in a continuous Vapor deposition more than a thousand layers on a rotating, cooled surface of Apply a few square meters before a replacement is performed.

US 6376018 (Kittler) dissolves product layers and release coatings dry under vacuum by applying a wax layer and a metal layer, eg aluminum, to one rotating roller per revolution. The roller runs past a scraper, which, without touching the roller skin, continuously scrapes material in layer form. The resulting mixture of wax and aluminum flakes is separated from each other in a further operation in the atmosphere by means of a strong wax solvent, for example by hot toluene or in a pressure vessel of over 36 bar by the action of liquid carbon dioxide. Since the scraped material no longer forms a coherent film, there are already flake-shaped particles that can be attacked by the solvent from all sides. However, the wax-aluminum mixture is extremely flammable when atmospheric oxygen is added. Such mixtures are known to be a component of incendiary bombs and solid propellants for rockets. After detachment, the product in the suspension must be cleaned of the release agent by numerous rinses of wax residues before it can be further processed.

The known method of blasting surfaces with carbon dioxide pellets, which is used for paint stripping of aircraft and other sensitive surfaces, proved to be useless for this application. Although the abrasive action is present, as well as the high speed of the removal, the process is accompanied by a layered ablation. The platelets embedded between layers of organic material experience undesirable roughening when exposed by the solid pellets. Another reason is that normally compressed air is used as the propellant gas of about 600 m ³ / h. The resulting risk of dust explosions due to a mixture of organic particles and atmospheric oxygen can not be ruled out. Replacing this large amount of propellant gas with nitrogen gas would prove uneconomical. Likewise, CO2 pellets do not embrittle the organic layers sufficiently. The temperature difference is about 100 ° C to the carrier is too low, as is the heat transfer between two solid phases, the CO2 pellets and the layer composite.

• a) Lackierprozesse am Träger unnötig macht
• b) Auch bei Vielfachschichten von mehreren hundert Lagen eine rasche Ablösung und Vereinzelung der Nanoplättchen ermöglicht
• c) Die Schichten aus Trennmittel und Produkt sollen schon vor dem Auswaschen des Trennmittels soweit vereinzelt werden, daß das in der Weiterverarbeitung angewandte Lösungsmittel nur Wege von wenigen Zehntel Millimeter zurückzulegen hat.

The object of the invention is to provide a device, a method and a product

• a) makes painting processes on the carrier unnecessary
• b) Even with multilayers of several hundred layers a rapid detachment and separation of the nanoplates allows
• c) The layers of release agent and product should be isolated before washing the release agent so far that the solvent used in further processing has only paths of a few tenths of a millimeter to cover.

These The object is achieved by a method according to claim 1, device according to the claims 13 to 17 and nanoparticles according to claims 18 to 21 solved. Inventive developments are the subject of the dependent claims.

• 1. Ablösung der Schichten in der selben Anlage in welcher die Herstellung der Viefachschichten erfolgt und Zerkleinern der Schichten auf wenige Zehntel Millimeter am selben Ort
• 2. Durchführung der Ablöseprozesses unter Inertgas
• 3. Vermeidung von Flüssigkeiten als Lösungsmittel in der Vakuumkammer. Erfahrungsgemäß lassen sich Feuchtigkeitsspuren nur durch langwieriges Evakuieren beseitigen und führen auch dann noch zu beträchtlichen Ausgasungen der Kammerwände.
• 4. Schaffung einer spiegelglatten, leicht erneuerbaren Glanzfläche, die als Konden-sations- Unterlage dient

To solve this problem, the fact was exploited that embrittle at temperatures of -196 ° C, all organic substances. Taking advantage of this effect on the production of nanoplates in the PVD process, this means that a way had to be found which fulfilled the following initial conditions:
mechanical detachment of the multilayers of organic release agent and product by a dry mechanical process with good, rapid action, without erosion of the carrier

• 1. separation of the layers in the same plant in which the production of the multiple layers takes place and crushing of the layers to a few tenths of a millimeter in the same place
• 2. Carrying out the removal process under inert gas
• 3. Avoidance of liquids as solvents in the vacuum chamber. Experience has shown that traces of moisture can be removed only by protracted evacuation and then still lead to significant outgassing of the chamber walls.
• 4. Creation of a mirror-smooth, easily renewable glossy surface, which serves as a condensation pad

The Invention will be described below with reference to the accompanying drawings, in which:

1 a device according to the invention for the production of nanoparticles in platelet form according to a first embodiment shows, and

2 a device according to the invention for the production of nanoparticles in platelet form according to a second embodiment shows.

The found solution is based on the methods described in Examples 1 and 2 and single steps:

First embodiment

In an apparatus after 1 First, a gloss layer on the support ( 2 ) which is applied in liquid form by known methods, such as pouring on rotation, rolling, spraying, knife coating and on the cooled carrier ( 2 solidified as a layer. Thereafter, a layer package consisting of release agent and product layers is applied by vapor deposition in up to several hundred alternating layers. In a subsequent step, the evaporation chamber ( 1 ) by a movable separation ( 3 ) from the evaporator sources ( 4 ) separated to prevent contamination of these by detached particles. The evaporator sources ( 4 ) are turned off and allowed to cool to about 800 ° C before the stripping process can begin. A reaction with atmospheric oxygen does not occur because during the detachment process only inert gas, which is preferably nitrogen, with the internals in the evaporation chamber ( 1 ) comes into contact.

m:

Menge an flüssigem Stickstoff in kg

η:

Anteil des auf den Träger wirksamen flüssigen Stickstoffs

r:

Verdampfungswärme kJ/kg

In the next step, liquid nitrogen is passed through one or more nozzles ( 5 ) as fine jets under high liquid pressure of up to 100 bar from a storage tank ( 6 ) via a commercial cryogenic pump ( 7 ) on the carrier ( 2 ) shot. Due to the high heat transfer coefficient of the evaporating liquid nitrogen with up to 3.6 × 10 ³ kJ / m ² ° C occurs a sudden cooling of the layer package and the applied below the gloss layer. The heat capacity of a 0.3 mm thick composite layer, which corresponds to about 1000 layers, depending on the thickness ratio of the release agent and the product layers is not more than 0.40 kJ / m ² ° C. The cooling of the layer package at the point of impact of the liquid jet is therefore in the range of milliseconds, without the carrier itself substantially cools. The reason for this is also to be sought in that by the larger by about the factor 3-6 larger thermal expansion coefficient of the organic intermediate layers at faster. Cooling the layers loosen and the desired cracking arises, which form an increased heat barrier to the wearer. The evaporating nitrogen simultaneously increases the pressure in the vapor-deposition chamber ( 1 ), starting from about 1 mbar. The heat of vaporization of the injected per cycle liquid nitrogen is Q = m × η × r = 60 × 0.8 × 199 = 9552 kJ

m:

Amount of liquid nitrogen in kg

η:

Proportion of liquid nitrogen acting on the carrier

r:

Heat of evaporation kJ / kg

As a result, 1500 to 3000 kJ / sm ^{2 are} extracted from the steel beam by heat conduction across the layer composite depending on the nozzle arrangement.

The organic release agent layers, in particular the underlying gloss layer, which was applied in liquid form and onto the support ( 2 ) solidifies, embrittles and shrinks due to the sudden cooling and cracking. The jet effect of the liquid nitrogen together with that of the outflowing cold gas breaks up the layer package into small particles. These are provided by the carrier ( 2 ) blown away. The resulting gas stream is directed by suitable internal internals, which surround the support ( 2 ) and in a filter ( 8th ) or cyclone. There, the particles separate, before the freed of solids nitrogen gas via an overflow valve ( 9 ) flows to the atmosphere. The entire removal process takes place at 1 bar internal pressure in the evaporation chamber ( 1 ).

The luster layer and its thickness has several functions: it forms a very smooth surface after solidification because it solidified from the melt phase. It also covers the surface roughness of the support ( 2 ), provided that its Rz value is less than half the layer thickness of the gloss layer. As materials for the gloss layer, a solvent-free and wax-free shellac have proven particularly suitable for application thicknesses of 10 to 100 micrometers. Higher thicknesses are possible, but not economical. The application of the gloss layer from the melt phase can take place both at 1 bar pressure and up to a partial vacuum of 10 mbar.

• a) Schmelzpunkte zwischen 120° und 240°C
• b) Ausreichende Versprödung und Verlust der Adhäsion am metallischen Unterlagen bei Temperaturen von weniger als –100°C, zu prüfen durch einen vergleichenden Kugelfalltest einer 20 mm Stahlkugel aus 0,2 Meter Höhe auf eine beschichtete metallische Unterlage. Im Auftreffpunkt soll mindestens eine Zone mit 4 mm Durchmesser zersplittert sein und sich von der metallischen Unterlage abgelöst haben.
• c) Nachweis des Oberflächenglanzes durch bekannte Meßmethoden der Glanzmessung
• d) Dampfdruck von kleiner 10^–5 mbar bei 25°C

Materials that are suitable as a glossy layer must meet the following requirements:

• a) Melting points between 120 ° and 240 ° C
• b) Sufficient embrittlement and loss of adhesion to metallic substrates at temperatures less than -100 ° C, to be tested by a comparative falling ball test of a 20 mm steel ball from a height of 0.2 meters onto a coated metallic substrate. At the point of impact, at least one zone of 4 mm diameter should be fragmented and detached from the metallic base.
• c) Verification of the surface gloss by known measuring methods of gloss measurement
• d) vapor pressure of less than 10 ^-5 mbar at 25 ° C

After the carrier ( 2 ) is freed from all adhering layers and a new application of the gloss layer has taken place, the separation between the evaporator sources ( 4 ) and the carrier ( 2 ) opened again, the Aufdampfvakuum is generated again and again alternating release agent and product layers are evaporated. The evaporation chamber ( 1 ) has not come in contact with any moisture in the stripping process, so that the evacuation process to the evaporation vacuum of about 10-4 mbar is completed in a few minutes. A new sputtering sequence can begin.

to increase the effect of the liquid Nitrogen jet settles Nitrogen gas of the liquid add in variable amount of 10 to 50 mole percent. Even more effective is to introduce dry ice pellets into the jet, however with a certain reduction in quality the surface the nanoplates. The surface of the carrier is not affected. As a metallic surface of the carrier is a commercially available Polishing of stainless steel or a hard chrome plating with a Roughness Rz <0.3 μ.

A further increase in the blasting effect can be achieved by the nozzles ( 5 ) are brought up to 3-5 mm to the support surface and with suitable, parallel to the surface of the support ( 2 ) mounted baffles ( 10 ) are equipped. As a result, the droplets are thrown back onto the carrier surface several times until they have evaporated. The radially from the nozzle ( 5 ) in the gap between supports ( 2 ) and the baffle plate ( 10 ) High-velocity gas additionally uses parts of the enthalpy of the gas for precooling.

The process of dry release under cold and jet exposure is already started shortly after the vapor deposition has been completed and all the vacuum valves have been closed. The resulting by evaporation of the liquid nitrogen gas expands at 1 mbar to 560,000 liters per liter of liquid nitrogen introduced. The flow velocity along the carrier surface is correspondingly high. In a typical industrial plant with a 3-meter plate and a chamber volume of 14,000 liters, at a supply of 6 liters per minute, after only 3.6 minutes of jet time, 1 bar of internal pressure arises in the vacuum chamber. The pressure in excess of 1.2 bar is released via the overflow valve ( 9 ) filtered filtered off.

By leave this dry process Many products are produced as nanoplates and also produce solvent-free in the course of processing. It is possible, the interspersed with organic release agent particles in one dry method, without using a solvent after cleaning WO 02/094945. Here are the collected particles in another Vacuum chamber heated by radiant heater up to 350 ° C at the same time Move. The release agent contained in the particles evaporates Completely and is chilled on a Condenser precipitated and disposed of. A removal of the release agent from the particles is also possible by dissolving in one Solvent, which in some cases can also be water. Particles derived from the material of the gloss layer, can be separated by known methods of flotation or together dissolved with the release agent become. The solvent to be covered Paths are only about half the particle size, about 0.1 to 0.3 millimeters. No superimposed Product layers that act as barriers hinder the dissolution of the Liners made of release agent. The particles can dry until further processing be stored, and they can then with a selected solvent which can be treated in the product to be produced, e.g. one Lack, in any case exists. This solvent may be from product to vary while product the methods according to the cited prior art to certain solvents are bound.

Second embodiment

Other variants of the method are with a device according to 2 possible:
In order to avoid dead times, which are due to the cooling of the evaporator sources, detachment of the layer composite, subsequent new evacuation and reheating the evaporator sources, it is advisable that the carrier 90 ° transversely to the evaporation under vacuum in a side chamber ( 11a ) is moved. At the same time, from an opposite side chamber ( 11b ) a purified carrier ( 2 ) in the evaporation chamber ( 1 ). The two side chambers ( 11a . 11b ) are sealed by vacuum-tight locks ( 12a . 12b ) from the vapor deposition chamber ( 1 ) separated. The detachment and the application of the gloss layer takes place in each case in the left or the right side chamber while at the same time the evaporation of a carrier ( 2 ) takes place in the middle chamber. Two porters in a total of three chambers take their positions alternately and simultaneously in two chambers.

The Structural arrangement of the disc-shaped carrier can be with horizontal axis or with vertical axis or any Rotary axis executed be just as the carrier a roller another body is. The evaporation direction can therefore be directed upwards as also done laterally.

Example I: (Laboratory experiment with a device according to the first embodiment of FIG 1 )

In a high-vacuum vapor deposition unit of 900 mm chamber diameter, which is equipped with a water-cooled support ( 2 ) of 800 mm diameter, are two 180 ° opposite Verdamp sources ( 4 ) at a distance of 700 mm below the turntable. A device consisting of a melting device for glossy layer material ( 14 ) and a delivery pump ( 15 ) brings an organic material, here dewaxed shellac as a brightener via an outlet nozzle ( 16 ) on the rotating support ( 2 ). It forms, depending on the feed pump ( 15 ) set a smooth spin-coated film on the support ( 2 ). The water cooling of the carrier ( 2 ) causes a rapid solidification of shellac. The desired layer thickness is 20 microns. The application of shellac takes place here at 40-100 mbar. Thereafter, the evaporation sources ( 4 ) heated to working temperature. By suitable barriers ( 3 ) between the sources prevents the materials from both sources from mixing. The sources are independently controllable at up to 18 kW output power and 0-10 V. Evaporation Source I is filled with an organic release agent, phenolphthalein, which vaporizes at about 250 ° C. The heating is done by radiation. The evaporation source II is an electrically heated graphite crucible of about 200 cm ³ capacity. This takes up 200 grams of granular magnesium fluoride. Its working temperature is 1450 ° C

The evaporation area per source is 120 cm ² each. After generating a vacuum of 3 × 10 ^-4 mbar, the still covered by a panel evaporation sources I and II are heated to 250 ° C and 1450 ° C. The temperature is measured by an electrically isolated tungsten-rhenium thermocouple (W5Re-W26Re) at the magnesium fluoride evaporation source and by a NiCr-Ni element at the phenolphthalein source, while the rotating support (Fig. 2 ) rotates at 50 rpm. The dependence of the amount evaporated per unit time of the evaporator flow was determined in preliminary experiments for both sources.

After heating both evaporator sources I and II ( 4 ) successively opens the aperture associated with the source I, then the aperture above the evaporation source II. The rotating support ( 2 ) is coated per revolution with one layer of phenolphthalein according to WO 02/094945 of about 150 nanometers and a magnesium fluoride layer of 120 nanometers. The carrier ( 2 ) is internally cooled with water at + 5 ° C to avoid self-heating during evaporation. After 250 revolutions turn off both barriers ( 3 ), the sources are turned off and cool off. Close the vacuum valves on the evaporation chamber.

To at this point, the process corresponds to the prior art, e.g. simultaneous vapor deposition from two sources.

To 3 Minutes cooling time is a on a via a vacuum-tight implementation of externally operated nozzle ( 5 ) at a distance of 10 mm from the turntable liquid nitrogen from a storage tank ( 6 ) of 200 liters via a booster pump ( 7 ) with 60 bar on the rotating support ( 2 ), whereby the nozzle is moved within 2 minutes from the radius r1 = 0 to the radius r2 = 450 mm. The gas-tight movement over 450 mm is achieved by the liquid nitrogen line is located within a 800 mm long highly flexible compensator of known design, which allows 500 mm stroke. After 40 seconds, the overflow valve ( 9 ), which opens at 1.2 bar chamber internal pressure. The gaseous nitrogen blows through a filter ( 8th ). This keeps the particles moving away from the carrier ( 2 ), back. To 2 Minutes of jet time, the supply of liquid nitrogen was shut off and the vacuum chamber opened by loosening the locks.

Theoretically, on the carrier ( 2 ) a total layer thickness of 67.5 μ evaporated after 250 alternating layers. The magnesium fluoride content corresponds to the theoretical value of 22.6 g, evaporated in 5 minutes. The from the filter ( 8th ) and from the evaporation chamber ( 1 ) were stirred in a bath of 20 ° C warm ethanol, filtered and rinsed with sufficient ethanol. The shellac applied as a liquid glossy dissolves also in ethanol.

Of the entire dissolution process of the release agent took place in less than a minute. Because phenolphthalein a very accurate indicator of basic pH values, no discoloration was observed after 6-step cascade rinsing Dropping a sodium carbonate solution can be seen more.

The The material thus obtained showed a platelet size in the x, y direction under the microscope between 20 and 80 μ. Further reductions are made by known milling techniques, e.g. by ultrasound in a liquid possible. The use of many other organic release agents is the same Procedure feasible. Information on this can be found in the patent disclosure WO 02094945 A1.

A repetition of the experiment without the use of the liquid applied brightener shows only an incomplete detachment of the layer composite from the carrier ( 2 ). The cause is to be found in that the vapor-deposited release coatings due to their very small thickness does not sufficiently penetrate through all layers breaking lines. This task is performed by the brightener layer, which is applied directly to the metallic support ( 2 ) is applied.

Example II: (Laboratory experiment with a device according to the first embodiment of 1 )

It the same arrangement was used as in Example I. The source II was this time filled with 500 g of silver granules.

The for silver elected Vapor thickness was determined in preliminary tests to 200 nanometers.

The replacement was done with the same cryotechnology.

The The result was 62 g of silver plates the size of 0.2 to 0.5 mm as a suspension in ethanol. The won platelets were about 10 times bigger than that of example I. The reason is probably to look into it that silver at low temperature still has a good ductility and comminution by embrittlement less effective.

• – Nanoplättchen aus Aluminium, Aluminium mit beidseitigem transparenten Schutzschichten aus Siliziumoxid, Magnesiumfluorid zur Herstellung von Lacken und Druckfarben
• – Nanoplättchen aus Siliziumoxid, Aluminiumoxid, Magnesiumfluorid als Träger-plättchen für die Weiterverarbeitung zu Effektpigmenten durch chemische Beschichtung mit Titanoxiden.
• – Plättchenförmige Nanopartikel aus Gold, Silber, Kupfer, Zinn zur Herstellung von elektrische leitenden Lacken oder Pasten
• – Plättchenförmige Nanopartikel aus Siliziumoxid oder Aluminiumoxid mit nachfolgender chemischen Behandlung zur Verwendung in Lacken mit erhöhter Oberflächenhärte, z.B. nach WO 02/094945. Solche Plättchen können zur Steigerung ihrer Härte einer Wärmebehandlung an Luft bei 400 bis 1000°C unterworfen werden, danach mit oberflächen- aktiven Substanzen im CVD- Verfahren gasförmig oder in chemischen Naßverfahren weiter behandelt werden.
• – Plättchenförmige Produkte aus Siliziumoxid, Magnesiumfluoprid, Kupfer, Silber und anderen Metallen, welche hergestellt werden durch Aufdampfen einer sich wiederholenden Schichtfolge von organischem Trennmittel, gefolgt vom einem sich im Dampfstrahl überdeckenden Gemisch aus Trennmitteldampf und dem Dampf des Produktes. In einem Folgeprozeß unter Vakuum wird das Trennmittel der Zwischen-schichten und das im Gemisch mit der Produktschicht kondensierte Trennmittel ausgedampft. Die notwendigen Temperaturen hierfür liegen im Bereich von 200°C bis 300°C. Die Ergebnis sind rückstandsfreie Hohlräume in den Plättchen mit extrem großer inneren spezifischen Oberfläche. Solche Plättchen können durch van der Waalsche Kräfte große Mengen an anderen organischen Substanzen an den Oberflächen der Hohlräume anlagern.
• – Es ist möglich, Wechselschichten aus zwei organischen Materialien aufzudampfen, wobei ein Material, welches das Trennmittel darstellt, in einem nachfolgenden Schritt außerhalb der Aufdampfanlage ausgewaschen wird und das andere als plättchenförmiges, unlösliches Nanopartikel erhalten bleibt. Mit dieser Methode ist es möglich, organische Plättchen im Bereich ab 40 Nanometer Dicke herzustellen. Solche Plättchen, zum Beispiel aus der Familie der Perylene, Benzimidazolone, Diketopyrrolopyrrole, Phthalocyanine, Quinacridone, Isoindolinone, Thiazine und Phenoxazine sind thermisch stabil, nicht oder nur wenig löslich. Sie sind von Interesse als Träger weiterer, auf ihnen angelagerten Substanzen.

Products which can be produced according to this invention in a specially prepared vapor deposition unit with multiple evaporators and a rotating support in a large number of alternating release agent and product layers are:

• - Nanoplates of aluminum, aluminum with double-sided transparent protective layers of silicon oxide, magnesium fluoride for the production of paints and printing inks
• - Nanoplates of silicon oxide, aluminum oxide, magnesium fluoride as carrier platelets for further processing into effect pigments by chemical coating with titanium oxides.
• - Platelet-shaped nanoparticles of gold, silver, copper, tin for the production of electrical conductive paints or pastes
• - Platelet-shaped nanoparticles of silica or alumina with subsequent chemical treatment for use in paints with increased surface hardness, for example according to WO 02/094945. Such platelets can be subjected to a heat treatment in air at 400 to 1000 ° C to increase their hardness, then further treated with surface-active substances in the CVD process in gaseous or chemical wet process.
• - Platelet products of silicon oxide, magnesium fluoride, copper, silver and other metals, which are prepared by vapor deposition of a repetitive layer sequence of organic release agent, followed by a vapor jet covering mixture of release agent vapor and the vapor of the product. In a subsequent process under vacuum, the release agent of the intermediate layers and the release agent condensed in a mixture with the product layer are evaporated. The necessary temperatures for this are in the range of 200 ° C to 300 ° C. The result is residue-free cavities in the platelets with an extremely large internal surface area. Such platelets can accumulate large amounts of other organic substances on the surfaces of the cavities by van der Waals forces.
• - It is possible to evaporate alternating layers of two organic materials, wherein a material which is the release agent is washed out in a subsequent step outside the vapor deposition and the other is retained as platelet-shaped, insoluble nanoparticles. With this method, it is possible to produce organic platelets in the range from 40 nanometers thick. Such platelets, for example from the family of perylenes, benzimidazolones, diketopyrrolopyrroles, phthalocyanines, quinacridones, isoindolinones, thiazines and phenoxazines are thermally stable, not or only slightly soluble. They are of interest as carriers of other substances deposited on them.

The physical limit of the possible number of such alternating layers is given by the limited heat dissipation through the layer package. As a result, the surface temperature increases and suppressed from a maximum value, which is between 80-120 ° C in organic release agents, the condensation. This temperature is strongly dependent on material and must be determined empirically. For the production of nanoparticles in platelet form, inorganic release agents can also be used in special cases. Numerous substances suitable for this purpose are known from the patent literature, such as Nacl, NaF, borax, for example, which do not react with magnesium fluoride or silicon oxide as the product layer and can be washed out with water. It is also possible to evaporate as a release agent substances with high vapor pressure. These can be removed residue-free in a further operation in a suitable vacuum distillation plant. This leaves platelet-shaped nanoparticles, which can be brought to the desired size in further operations by grinding and classifying. An advantage of this method is that the Next Processing only in dry processes.

It Thus, a device for the production of nanoparticles in platelet form by vapor deposition of a number of more than 10 alternating organic Release agent layers and product layers in the PVD process at a vacuum of better than 1 Pa, characterized in that that in the Step a) with a continuously rotating about an axis carrier one in liquid Shape on the carrier applied applied meltable, organic gloss layer becomes alternate with a thickness of 5 to 250 microns in step b) Release agent and Product layers are vapor-deposited in step c) the evaporation sources from carrier spatial are separated and in step d) liquid gas of less than -25 ° C over one or several nozzles under pressure on the wearer flows, thereby the applied in step a) gloss layer under cracking brittle and the layer package itself from the carrier replaces, is separated into small particles and blown away from the carrier, wherein the entrained in the gas stream, separated particles in a filter or in a cyclone deposited and are collected and subsequently step a) is repeated in step e) the separation between the evaporator sources and the carrier Undone is generated, the Aufdampfvakuum again and again alternating Release agent and product layers are evaporated.

A Device according to the first aspect is according to the second Aspect characterized in that the separation according to, step c is formed as a respective vacuum-tight lock, which each one Side chamber locks, wherein the step d each in one of Side chambers take place and at the same time in the evaporation chamber the evaporation a second carrier according to step b takes place.

A Device according to the first aspect is corresponding to a third Aspect characterized in that the separation as part of the Evaporating chamber is formed and the processes of vapor deposition and the replacement in chronological order.

A Apparatus according to the first to third aspects is accordingly A fourth aspect, characterized in that the liquid gas to increase the Separating action the same or another gas or pellets of solid carbon dioxide supplied become.

A Device according to the first to fourth aspects according to a fifth Aspect, characterized in that the liquid gas has a temperature of less than -25 ° C or is chemically reactive neither with the release agent nor with the product

A Apparatus according to the first to fifth aspects is accordingly the sixth aspect, characterized in that liquid nitrogen as liquid gas is used

A Device according to the first to sixth aspects is accordingly the seventh aspect, characterized in that the filter or cyclone of the Step 1 d over has an emptying device, which deposited particles are continuous or discontinuous discharges.

A Apparatus according to the first to seventh aspects is accordingly an eighth aspect, characterized in that the carrier is a cooled to its axis of symmetry is rotating roller, disc or cone

A Apparatus according to the first to eighth aspects is accordingly a ninth aspect, characterized in that the nozzles support the carrier in a time / space grid brush, change their angle of attack to the carrier and operated pulsating can be.

One Products made after one or more of the first to the next Aspect for use as platelet-shaped nanoparticles made of aluminum, aluminum with transparent layers on both sides of silicon oxide, magnesium fluoride for the production of paints, printing inks and for incorporation in thermoplastics

One Products made after one or more of the first to ninth Aspect for use as platelet-shaped nanoparticles made of silicon oxide, aluminum oxide, magnesium fluoride as carrier platelets for further processing to effect pigments by subsequent chemical coating or by a CVD method with titanium tetrachloride with titanium oxides.

A product prepared according to one or more of the first to ninth aspects for use as platelet-shaped nanoparticles containing gold, silver, copper, tin or indium for the production of electrical conductive paints or pastes

One Products prepared according to one or more of claims 1 to 9 for use as platelet-shaped nanoparticles of silica or alumina followed by chemical Treatment with surface active organic substances for use in paints with increased surface hardness

product manufactured according to one or more of the first to ninth aspects for use as platelets with big ones inner surface by simultaneous evaporation of the product layer and the same release agent in an overlapping Steam jet, followed by heating and moving under vacuum of the detached one Layer package to more than 200 ° C, wherein the release agent evaporates and platelets with cavities as Product leaves behind

product manufactured according to one or more of the first to ninth aspects for use as platelets made of organic material, by evaporation of a contrary to Release agent insoluble, in a vacuum of an undiminished vaporizable substance from the group of perylenes, Benzimidazolones, diketopyrrolopyrroles, phthalocyanines, quinacridones, Isoindolinones, thiazines and the phenoxazines, wherein in a subsequent Procedure the release agent is washed out

LIST OF REFERENCE NUMBERS

Claims (21)

Process for the production of nanoparticles in platelet form by vapor deposition of a number of more than 10 layers, of which alternately a layer of a release agent, followed by one or has multiple product layers, in the PVD process at a better vacuum as 1 Pa, characterized by the steps a) Apply one fusible, organic glossy layer in liquid form with a thickness from 5 to 250 microns on a turning axis Carrier, b) Vapor deposition of a layer having the release agent, and the further layers comprising the product on the gloss layer to form a layer package and c) passing liquid gas with less than -25 ° C over one or more nozzles under pressure on the wearer in in such a way that the gloss layer applied in step a) under cracking brittle, the layer package itself from the carrier detaches and isolated into small particles The method of claim 1, wherein the liquid gas in step c) is directed onto the carrier in such a way that the Gloss layer and the vapor-deposited on it release layers and Product layers from the carrier are blown off and wherein the carrier in step a) continuously turns around its axis. The method of claim 1 or 2, comprising a step d) performed after step c) is and in which the entrained particles in the gas stream deposited in a filter or in a cyclone and collected and then in a further process outside the evaporation chamber be further processed by dissolving the glossy layer material and the release agent material, followed by a milling process. Method according to claim 3, wherein after step d) the steps a) to d) are repeated. Method according to claim 4, being in step c) before passing liquid Gas on the carrier in sub-step c.2) in a step c.1) the evaporator sources from the carrier spatial be disconnected and being after depositing and collecting in Sub-step d.1) of step d) in a sub-step d.2) the separation reversed between the evaporator sources and the carrier is and the Aufdampfvakuum is generated again. Method according to one of the preceding claims, wherein the liquid Gas in step c) to increase the detachment effect the same or another gas or pellets of solid carbon dioxide supplied become. Method according to one of the preceding claims, wherein the liquid Gas in step c) has a temperature of less than -25 ° C. and is not chemically reactive with either the release agent or the product Method according to one of the preceding claims, wherein as a liquid Gas more fluid Nitrogen is used Method according to one of the preceding claims, wherein in step b) a layer comprising a release agent, and a Layer comprising the product, are applied by vapor deposition, to create the more than 10 layers. Method according to one of the steps 1 to 8, wherein in step b) a layer comprising a release agent, and a Layer containing the product and a material with high vapor pressure and those from overlapping steam jets can be generated simultaneously, vapor-deposited, and in one step e) carried out after step c) and in which the detached Layer package in another Valkuumkammer heated to more than 200 ° C. and agitated so that the material evaporates out with high vapor pressure and platelets with big ones inner surface to be obtained. The method of claim 10, wherein in step e) also evaporates the release agent and wherein the release agent the Has material with high vapor pressure. Method according to one of the steps 1 to 8, wherein in step b) the product is insoluble in contrast to the release agent Has substance that is evaporable without decomposition in vacuo and the from the group of perylenes, benzimidazolones, diketopyrrolopyrroles, Phthalocyanines, quinacridones, isoindolinones, thiazines and phenoxazines and step e) performed after step c) and in which the release agent is washed out of the layer package, around tiles to produce from organic material. Apparatus for carrying out the method according to claim 5 with a vapor deposition chamber for carrying out step b), one Side chamber for execution from step c.2) a vacuum tight lock, with which the spatial Separation in step c.1) takes place, to shut off a side chamber, in which the device is designed in such a way that step c.2) a first carrier executed in a side chambers and at the same time in the evaporation chamber, the vapor deposition of a second carrier according to step b) executed becomes. Apparatus for carrying out the method according to one of claims 1 to 12, with a vapor Chamber for the execution of step b) and c) in chronological order. Apparatus for carrying out the method according to one the claims 3 to 5 and 6 to 8, when dependent on claim 3, wherein the filter or cyclone from step d) an emptying device for continuous or discontinuous discharging of deposited Particles. Device according to one of claims 13 to 15, wherein the carrier is a cooled, rotating roller or disc or a roller rotating about its axis of symmetry its symmetry axis is rotating other body. Device according to one of claims 13 to 15, wherein the carrier by the nozzles in a time / path grid bestreichbar, their angle of attack to the carrier changeable is and these are pulsating operable. Platelet-shaped nanoparticles, manufactured according to one of the methods of claims 1 to 9, for the production of paints, printing inks and for incorporation in thermoplastic Plastics, where the nanoparticles aluminum, aluminum with bilateral transparent layers of silicon oxide, magnesium fluoride have. Platelet-shaped nanoparticles, manufactured according to one of the methods of claims 1 to 9, for use as carrier platelets for further processing to effect pigments by subsequent chemical coating or by a CVD method with titanium tetrachloride with titanium oxides, wherein the nanoparticles silica, alumina, magnesium fluoride exhibit. Platelet-shaped nanoparticles, manufactured according to one of the methods of claims 1 to 9, for the production of electrical conductive paints or pastes, wherein the nanoparticles comprise gold, silver, copper, tin or indium. Platelet-shaped nanoparticles for use in paints with elevated Surface hardness, where the nanoparticles have silica or alumina and these after production according to one of the methods of claims 1 to 9 of a chemical treatment with surface-active organic substances are unterziehbar.