DE102005060018A1 - Effect pigment for use in e.g. coatings, cosmetics, printing inks, plastics, papers, food dye, medicament coating and as tracers, comprises that it is based on structured plate-forming substrates - Google Patents

Abstract

Effect pigment (A) based on structured plate-forming substrates (where (A) on irradiation with electromagnetic radiation is retro-reflective). Independent claims are also included for the preparations of (A).

Description

The The present invention relates to effect pigments based on structured platelet-shaped substrates, wherein the effect pigments when irradiated with electromagnetic Radiation retroreflective, methods of making the retroreflective Pigments and their use in coatings, cosmetics, lacquers, Inks, inks, toners, in ceramic materials, glasses, paper, in Plastics, foils, in security printing, in security features, in documents and passports, for food coloring, as Tracer or in drug coatings as well for the preparation of pigment preparations and dry preparations.

Of the Use of luster or effect pigments is widespread. at Automotive paints, decorative coatings of all kinds and in the coloring of plastics, paints and inks, in particular paints for the Security printing, as well as in applications in decorative cosmetics are Such pigments have become indispensable. In the surrounding Matrix, these pigments are ideally aligned parallel to the surface of the Coating and unfold by a complicated interaction of refraction at boundary layers of different materials, interference, Reflection and absorption of the striking light their optical Effect. It stands for the different use cases a brilliant color scheme, change between different colors depending on Viewing angles, so-called color flops, or changing brightness impressions are the focus of attention Interest.

The optical effects are based on different interactions the incident light with the individual effect pigment particles. So part of the incident radiation, especially in metallic Effect pigments, smooth or diffusely reflected, that is reflect the surfaces of the pigments the incident light in one direction or in scattered form uniformly (diffused) in all directions. It only affects a small part of the reflected Light on an observer. There are also mixed forms of the individual Reflections, that is directed and diffuse reflection are equally present. Furthermore occur, especially with effect pigments of multi-coated Substrates, refractions of light at the interfaces between to the individual layers.

effect pigments The above types are common and long known. These include, in particular, metallic effect pigments and effect pigments based on layered materials, e.g. Mica coated with metal oxides. By the construction multilayer systems become at the interfaces of the individual layers, in addition to refraction phenomena, additional Creates reflection levels that can enhance the shine in the sum. Also but these are systems whose perceptible gloss primarily based on directional or diffuse reflection.

Another optical effect can be observed for pigments with uniformly arranged structures. Because of the wave nature of the light, diffraction occurs at these structures, which is also called diffraction. The size range of the structures is in the range of 1 μm and less. In particular, such diffraction phenomena can always be observed when the geometric structures have a size that is comparable to the wavelength of the irradiated radiation. The physical basis for the diffraction is the interference of waves, that is their superposition, which leads to a mutual reinforcement (constructive interference) or to a mutual attenuation (destructive interference) or even to extinction. With suitably selected sizes for the structures, optical effects associated with the appearance of rainbow colors can be observed. Diffractive pigments of this type are known and can be found, for example, in DE 102 51 534 , US 2003/0190473, US 2003/0224164 or US 6,692,830 ,

A special type of reflection is retroreflection. In retroreflection, also reflection called, the incident radiation is a large proportion reflected back towards the light source. Retroreflective body therefore reflect the light always back to the light source, regardless of the angle at which the light beam strikes the surface and the direction of the light beam. There is an observer near the light source, the illuminated material therefore appears special bright. Observers away from the light source take the illuminated one surface however, true as dark, since no light is reflected back to them becomes.

Retroreflective items are well known. These are generally films of several layers, usually on a reflective layer as possible, a large number of transparent balls, glass beads are applied in most cases. The balls break the incident light, focus the beam and pass it on to the underlying reflective layer. This layer reflects the collimated beam back, it is refracted on the glass beads and sent back to the light source. This arrangement has the disadvantage that when embedding the glass spheres in the usually polymeric matrix only one There is little difference between the refractive indices of the individual materials, which limits the functioning of the above materials. As a by-pass, alternative retroreflective systems have been proposed which also include a complex multilayer construction. The balls are only partially embedded, whereby an air / glass boundary layer is generated, which leads to an increase in the refractive index difference in the system glass / air.

retroreflective Paints describes WO 03/016964. This is based on a conventional layer of absorption or effect pigments a layer of microspheres applied. The retroreflective properties of the microspheres are combined with the color properties of the pigments.

Another approach to retroreflective systems is the use of triple mirrors. A triple mirror is a rectangular arrangement of three reflecting surfaces, for example mirrors, which because of the particular geometric arrangement throw the incident light rays back in the same direction from which they came. Due to the principle, a small lateral offset usually occurs. The amount of offset depends on the edge length of the mirrors. The functioning of a triple mirror can also be ensured without a highly reflective coating - usually aluminum or silver - if the geometric arrangement of the shape is changed, that the principle of total reflection is used. 1 shows the principal mode of operation of the triple mirrors.

ist, und die Brechzahl des ersten Mediums n₁ größer ist als die des zweiten Mediums n₂ n₁ > n₂ Total reflection is an optical phenomenon in which light is not refracted when hitting a boundary layer between two media with different refractive indices, but is completely reflected. Total reflection only occurs when the angle of the incident light to the incidence slot, the so-called angle of incidence θ, is greater than the so-called critical angle of total reflection

is, and the refractive index of the first medium n _{1 is} greater than that of the second medium n ₂ n ₁ > n ₂

For angles of incidence greater than θ _c , the angle of reflection would, according to Snell's law, have to be greater than 90 degrees, which, however, contradicts the essential premise that the outgoing beam always passes through the surface. Therefore, the light is completely reflected. In triple mirrors now incident on a more dense optically dense medium light (boundary layer air / glass) is prevented because of the total reflection at the exit from the optically denser medium and, due to the 90 degree arrangement of the cube corner, parallel to the incoming beam, reflected. 2 shows a two-dimensional representation of the total reflection in a retroreflector.

Out the prior art are retroreflective systems with triple mirrors known, e.g. in the field of passive safety the "cat's eyes", for example in guide posts to the road boundary. These moldings are mostly by injection molding of PMMA or other suitable polymers, z.T. also made of glass. With all these retroreflectors For the most part, the principle of total reflection is used, i. as highly effective Reflector layer serves the interface of the optically denser (polymer or glass) to the optically thinner Medium (air). If this interface is e.g. by condensation (precipitation finest Water droplets) disturbed, the effectiveness of this arrangement decreases z.T. very drastically because the refractive index difference by coupling a visually denser Medium - im Example water - now clearly becomes smaller. Even more dramatic consequences have the painting of such Parts.

For many Applications, it is therefore important to the back of the triple mirror too to seal. This can in principle purely mechanically by the installation in a housing, be realized by applying a protective film or the like. In principle, a vapor deposition with a highly reflective layer prevent this problem. For many applications is this extra Coating step, however, too expensive.

Out US 5,763,049 Reflection films are known with triple mirror characteristic. These films are based on microscopically small triple mirrors, often called microprisms, with an edge length of approx. 200 μm. The structure uses the already described total reflection at the polymer / air interface.

The are retroreflective sheeting described in the prior art subject to fundamental restrictions in their applications and processability. The films can be applied only on straight or at best 2-dimensional curved surfaces. 3-dimensional structures such as e.g. Balls or with depressions provided surfaces like For example, car plates are not reasonably coatable. Something more complex Structures can also be cut only by cutting larger sheets of paper Foils, e.g. with the help of a cutting plotter. These Procedure is u.a. For the production of traffic signs applied. It falls very much a lot of cutting waste and more complex structures, e.g. multiline Texts are very difficult to handle.

One Another problem is the polymeric structure of these films. Depending on the application, these materials of the weather, especially the Sunlight, mostly complete exposed. The organic materials used in the films can be used in the Degrade sunlight. The speed of the degradation is in principle the material used (polymer type), the optionally used stabilizers, such as. UV absorber, and the radiation intensity or duration dependent. Just through the use of very high quality raw materials and stabilizers Is it possible, Lifetime warranties of up to 10 years on these materials be given by the manufacturer. In many applications, however These lifetime guarantees too short. For example in the automotive industry for a car paint lifetime warranties of up to 30 years required.

The in WO 03/016964 also has some systemic disadvantages. For example, to make a retroreflective Coating a double coating necessary. First, it will be there the so-called "basecoat film "consisting from a coloring layer, e.g. a color pigment in a paint, applied. Subsequently In a second process step, a layer is applied to this layer applied glass beads with a diameter in the range of 10-100 microns. The resulting multilayer coating system is in the achievable efficiency The retroreflection severely limited, since it is the structure of the The simplest type of retroreflective sheeting resembles in principle.

It Therefore, the task was to give objects and moldings a to confer retroreflective effect without the above-mentioned disadvantages to have to accept. This object is surprising by pigments according to the present invention and solved in an advantageous manner.

object Accordingly, the present invention is based on effect pigments structured platelet-shaped substrates, characterized in that the effect pigments when irradiated are retroreflective with electromagnetic radiation.

In order to the effect pigments according to the present invention Invention retroreflective when irradiated with electromagnetic radiation are, is the surface the structured platelet-shaped substrates arranged from regularly Triple mirrors. The triple mirrors can be trigonal, tetragonal, square, be pentagonal or hexagonal faceted. The faceting in the sense The present invention means the shape of the individual mirror planes within a triple mirror. The shape of the mirror planes within a Triple mirror has an influence on the retroreflectivity (quotient from re-radiated and irradiated amount of light). Especially in the outdoor areas The triple mirror can - depending on selected Geometry - no light more retroreflective reflected become. These light components are then laterally, for example by simple reflection, emitted. Examples of the mentioned structuring can be found, for example, in US 2003/0133194, the disclosure of which hereby incorporated by reference.

The single triple mirror can be arranged arbitrarily to each other in the effect pigments, preferably the triple mirrors are trigonal, tetragonal, square, pentagonal or arranged hexagonally. Depending on the selection of the arrangement can be in closed structuring can be achieved, in particular in the hexagonal arrangement, in other cases, a non-opaque Arrangement can be achieved, that is between the triple mirrors There are unstructured areas that do not contribute to retroreflectivity. Preferably there is a hexagonal arrangement of the triple mirrors, because in this way the retroreflective effect can be optimized.

combinations from different faceting and arrangements are there also possible. So can square faceting with hexagonal arrangement under irradiation show a retroreflective effect.

The edge length the cusp mirror is in the range of 1 to 25 μm, preferably in the range of 1 to 10 μm and especially at 2 to 5 μm. At edge lengths below 1 μm increasingly diffractive effects are observed, which in the context of present invention undesirable are. Edge lengths over 25 μm lead to very rough structuring, which is the suitability of the resulting Effect pigments in the common ones Systems such as e.g. Paints or in the printing area, increasingly difficult.

The The structuring described above can only on one side of the substrates exist, that is one Page has the structuring, and that of the structured page opposing area is smooth.

Effect pigments of this type show retroreflectivity only when irradiated from one side. The radiation must radiate into the effect pigment on the unstructured side in order to show retroreflectivity on the structured side by total reflection at the pigment-surrounding medium interface. Moreover, it is also possible that both sides of the effect pigments according to the invention are structured. In this case, the structuring must but are offset from each other, that is, the areas of the surfaces that are structured on one side must be unstructured on the opposite side and vice versa. This ensures that retroreflection occurs on each side as light is received.

The effect pigments according to the present invention are based on structured platelet-shaped substrates, the substrates being able to consist of metal oxides, metal oxide hydrates, metal suboxides, metals, metal fluorides, metal nitrides, metal oxynitrides, polymers or mixtures of these materials. The substrates are preferably composed of metal oxides, in particular of glass, synthetic mica, Al ₂ O ₃ , SiO ₂ , TiO ₂ , ZrO ₂ , SnO ₂ , iron oxides, of metals, in particular aluminum, titanium, nickel, chromium, silver or alloys, or from metal fluorides, in particular magnesium fluoride or calcium fluoride, polymers or mixtures of these materials.

For use Polymers suitable as substrates are, for example, melamine-formaldehyde resins.

When glasses are all known in the art high or low refractive Glasses, e.g. E-glass or C-glass. Preferably, high-index glasses are used, to the highest possible Proportion of total reflection in the surrounding medium, e.g. a paint, to reach.

Of the Diameter of the substrates is usually between 1 and 250 μm, preferably between 2 and 150 microns. For automotive applications and industrial coatings, the diameter is preferably 5 to 45 μm, in the pressure range 10 to 25 μm and in cosmetics preferably 50 to 150 microns.

The Thickness of the pigment platelets can vary widely and is responsible for the effects that occur critical. Preferred is the thickness 0.3 to 2 microns. The mean aspect ratio the platelet-shaped substrates, this means The relationship from the mean length measurement, which here corresponds to the mean diameter, to the mean thickness measured value, is usually 5 to 200, preferably 20 to 150 and particularly preferably 30 to 120.

Structured effect pigments based on the above-mentioned materials exhibit retroreflectivity upon irradiation with electromagnetic radiation. The intensity of the retroreflectively reflected radiation depends not only on the type of structuring but also on the material used and the surrounding medium. For example, a low refractive index material such as SiO ₂ or MgF _2, is used, consisting of this material effect pigments are preferably used in the high refractive index coatings. Due to the refractive index difference between the pigment material and the surrounding medium, the desired total reflection at the triple mirrors and thus retroreflectivity occurs at the interface.

To enhance the retroreflective properties, the structured platelet-shaped substrates may additionally be coated. Accordingly, in a further embodiment of the present invention, the effect pigments are additionally coated with one or more transparent, semitransparent and / or opaque layers comprising metal oxides, metal oxide hydrates, metal suboxides, metals, metal fluorides, metal nitrides, metal oxynitrides or mixtures of these materials. The metal oxide, metal oxide hydrate, metal suboxide, metal, metal fluoride, metal nitride, metal oxynitride layers or mixtures thereof may be low (refractive index <1.8) or high refractive index (refractive index> 1.8). Suitable metal oxides and metal oxide hydrates are all metal oxides or metal oxide hydrates known to the person skilled in the art, such as, for example, Example, alumina, alumina hydrate, silica, Siliziumoxidhydrat, iron oxide, tin oxide, cerium oxide, zinc oxide, zirconium oxide, chromium oxide, titanium oxide, in particular titanium dioxide, titanium oxide and mixtures thereof, such as ilmenite or pseudobrookite. As metal suboxides, for example, the titanium suboxides can be used. Chromium, aluminum, nickel, silver, gold, platinum, lead, germanium, titanium, copper or alloys are suitable metals, for example, magnesium fluoride is suitable as the metal fluoride. As metal nitrides or metal oxynitrides, for example, the nitrides or oxynitrides of the metals titanium, zirconium and / or tantalum can be used. Preference is given to applying metal oxide, metal, metal fluoride and / or metal oxide hydrate layers and very particularly preferably metal oxide and / or metal oxide hydrate layers to the structured substrates. Furthermore, multi-layer constructions of high-refractive and low-refractive index metal oxide, metal oxide hydrate, metal or metal fluoride layers can also be present, alternating preferably high and low refractive index layers. Particularly preferred are layer packages of a high and a low-refractive layer, wherein one or more of these layer packages can be applied to the effect pigments. The order of the high- and low-index layers can be adapted to the material of the structured substrates in order to include the substrates in the multi-layer structure. In a further embodiment, the metal oxide, metal oxide hydrate, metal suboxide, metal, metal fluoride, metal nitride, metal oxynitride layers or mixtures thereof may be mixed or doped with colorants and / or other elements. Suitable colorants or other elements are, for example, organic or anorgani color pigments such as colored metal oxides, for example magnetite, chromium oxide or color pigments such as Berlin blue, ultramarine, bismuth vanadate, thenard blue, or organic color pigments such as indigo, azo pigments, phthalocyanines or carmine red or elements such as yttrium or antimony. Effect pigments containing these layers show a high color diversity with respect to their body color and in many cases can additionally show an angle-dependent change in color (color flop) due to interference.

The outer layer of the effect pigments in a preferred embodiment is a high refractive index metal oxide or a metal. This outer layer may additionally be part of a layer package on the abovementioned layer packages or, for high-index substrates, for example of TiO ₂ , titanium suboxides, Fe ₂ O ₃ , SnO ₂ , ZnO, ZrO ₂ , Ce ₂ O ₃ , CoO, Co ₃ O ₄ , V ₂ O ₅ , Cr ₂ O ₃ and / or mixtures thereof, such as ilmenite or pseudobrookite exist. TiO ₂ is particularly preferred. As metals, in particular chromium, aluminum, nickel, silver, gold, platinum, lead, germanium, titanium, copper, very particularly preferably chromium, aluminum, nickel, silver, gold are suitable.

The additional Coating can be at least on one side of the structured Substrate present. About that In addition, it is also possible that the additional applied one or more layers of the structured substrates envelop. The choice of coating materials and between a one-sided or enveloping Coating depends on the type of structuring and the selection of the medium into which the effect pigments are to be incorporated.

If, for example, low-index materials are used for the structured substrates, then an additional coating with a high-index material, eg TiO ₂ , can take place both on one side, eg on the structured side, and enveloping. In both cases, the refractive index differences necessary for the occurrence of total reflection are increased and the resulting retroreflective effect is enhanced. If metals are used for the additional coating, then a one-sided coating on the structured side is recommended. In this way, a kind of mirroring is produced, which leads to an increase in the retroreflectivity when irradiated on the unstructured side.

In a further embodiment of the present invention, the effect pigments have a uniform shape and size. The effect pigments may have a circular or elliptical shape or be a polygon V _n , with
n = the number of corners and
n ≥ 3.

The Effect pigments of this embodiment have a uniform particle size and geometry on, which allow the color strength and the hiding power to adjust the pigments individually. By in this embodiment present uniform size distribution the pigments account for the conventional ones elaborate classification operations, which allow only an insufficient separation of the size fractions. The uniform particle size prevents the blocking of filters, sieves and nozzles when using the pigments of the invention. About that In addition, the effect pigments of the invention show an improved gloss due to lack of light scattering on particles different size. Further let the pigments of the invention Produce in a simple way and in a variety of applications apply.

The effect pigments preferably have the shape of a polygon V _n , where n represents the number of corners and n ≥ 3. In this case, n represents an integer, wherein preferably n = 3, 4, 5, 6, 7 or 8. The polygons can be formed regularly or irregularly. Very particular preference is given to n = 4 (quadrilaterals) and n = 6 (hexagon), whereby all conceivable shapes such as square, trapezoid, rhombus, rhombus or rectangles with different edge lengths of the polygons are included for the quadrilateral. In addition, combinations of several shapes and sizes are conceivable, such as the combination of circles and diamonds.

In a further embodiment of the present invention, the effect pigments according to the invention can furthermore be provided with an additional stabilizing organic coating as outer layer. Examples of such coatings can be found, for example, in EP 0 632 109 . US 5,759,255 . DE 43 17 019 . DE 39 29 423 . DE 32 35 017 . EP 0 492 223 . EP 0 342 533 . EP 0 268 918 . EP 0 141 174 . EP 0 764 191 , WO 98/13426 or EP 0 465 805 , the disclosure of which is hereby incorporated by reference. Effect pigments containing an organic coating, for example of organosilanes or organotitanates or organozirconates, in addition to the optical properties already mentioned, additionally exhibit increased stability to weather influences, such as moisture and light, which is of particular interest for industrial coatings and in the automotive sector. The stabilization can be improved by inorganic components of the additional coating. Overall, the respective proportions for the additional stabilizing coating should be selected such that the optical properties of the effect pigments according to the invention are not significantly affected.

X

= OH, Halogen, Alkoxy, Aryloxy

Z

= Si

R

= Alkyl, Phenyl oder Wasserstoff

B

= organische, zumindest bifunktionelle Gruppe (Alkylen, Alkylenoxyalkylen)

Y

= Alkyl-, Amino-, substituierte Amino-, Hydroxy-, Hydroxyalkyl-, Siloxan-, Acetoxy, Isocyanat-, Vinyl-, Acryloyl-, Epoxy-, Epoxypropyloxy-, Imidazol- oder Ureidogruppe

n, m

= 0,1,2,3 mit n+m ≤ 3 bestehen.

Suitable organosilanes for the additional stabilizing coating are, for example, silanes of the general formula X _4-n ZR _nm (-BY) _m With

X

= OH, halogen, alkoxy, aryloxy

Z

= Si

R

= Alkyl, phenyl or hydrogen

B

= organic, at least bifunctional group (alkylene, alkyleneoxyalkylene)

Y

= Alkyl, amino, substituted amino, hydroxy, hydroxyalkyl, siloxane, acetoxy, isocyanate, vinyl, acryloyl, epoxy, epoxypropyloxy, imidazole or ureido group

n, m

= 0,1,2,3 with n + m ≤ 3.

The organosilanes consist of an anchor group (X _{4 nm} Z), the z. B. can bind to the surface of the pigment, at least one hydrophobic group (R, B) and one or more alkyl or functional groups (Y). Preferably, the anchor group consists of alkoxysilanes, which can be converted by hydrolytic reaction conditions into corresponding hydroxyl groups.

By the choice of suitable functional groups, the organosilane the Requirements are adjusted. In addition, depending by coating order, by reaction of the functional Groups with corresponding functionalities in the application media additional Bonds between pigment and medium via the organosilane produced become. In a particular embodiment becomes the surface the effect pigments of the invention with a combination of organic adapted to the feed functionalities modified. For this purpose, the use of mixtures is also suitable different organosilanes. The hydrophobicity of the particle surface can by integration of alkyl-containing coupling reagents, such as. As alkyl silanes, also be adjusted. In addition to the organosilanes is also the use of their hydrolysates and their homogeneous and heterogeneous oligomers and / or polymers are preferred, which also alone or in combination with the silanes already described can be used. in the Particular preference is given to mixtures of different organosilanes, in particular with mutually different functional groups Y, whose use ensures a special scope.

Examples of organosilanes are propyltrimethoxysilane, propyltriethoxysilane, isobutyltrimethoxysilane, n-octyltrimethoxysilane, i-octyltrimethoxysilane, n-octyltriethoxysilane, n-decyltrimethoxysilane, dodecyltrimethoxysilane, hexadecyltrimethoxysilane, vinyltrimethoxysilane, octadecyltrimethoxysilane, preferably vinyltrimethoxysilane. Suitable oligomeric, alcohol-free organosilane are, among others, those sold under the trade name "Dynasylan ^®" by the company. Sivento products, such. As Dynasylan HS 2926, Dynasylan HS 2909, Dynasylan HS2907, Dynasylan HS 2781, Dynasylan HS 2776, Dynasylan HS 2627. In addition, oligomeric vinylsilane and aminosilane hydrolyzate are suitable as organic coating.Functionalized organosilanes are, for example, 3-aminopropyltrimethoxysilane, 3-methacryloxytrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, beta- (3,4-epoxycyclohexyl) -ethyltrimethoxysilane, gamma-isocyanatopropyltrimethoxysilane, 1, 3-bis (3-glycidoxypropyl) -1,1,3,3-tetramethyldisiloxane, ureidopropyltriethoxysilane, preferred are 3-aminopropyltrimethoxysilane, 3-methacryloxytrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, beta- (3,4-epoxycyclohexyl) -ethyltrimethoxysilane, gamma- Isocyanatopropyltrimethoxysilane Examples of polymeric silane systems are described in WO 98/13426 and are described, for example, in US Pat B. sold by the company. Sivento under the trademark Hydrosil ^® .

Also The present invention relates to processes for the preparation the effect pigments according to the invention, wherein structuring into a platelet-shaped substrate by means of a structured body embossed is, with the structuring of the body is chosen such that the embossed Substrate upon irradiation with electromagnetic radiation retroreflective is.

When Substrates for the imprint The structuring is particularly suitable metals such. aluminum or titanium, or other materials that have sufficient moldability in particular glass, which is at a temperature around the softening point of the glass was or polymers. Suitable examples of the materials are already called in advance.

The embossing is done with a stamping tool, which has to be embossed structuring as a negative image. The stamping tool can have any shape, for example as a stamp or in the form of a roll or roller. Preferably, the embossing tool is a structured roller or roller with which large areas of the substrate can be provided with the structuring. Methods for direct embossing are generally known to the person skilled in the art and can be found, for example, in US Pat DE 101 34 362 or DE 101 58 347 , A detailed overview of the state of the art can be found in Peter Merz, "Production of microstructured surfaces in glass and polymer by replicative process technologies", Shaker-Verlag GmbH (ISBN 3-8322-1628-6).

• a) Aufbringung eines Films enthaltend einen Substratprecursor auf einen strukturierten Träger,
• b) Verfestigung des Films durch Trocknung,
• c) Entwicklung eines Substrates durch chemische Reaktion aus dem Substratprecursor,
• d) Abtrennung des Substrates vom strukturierten Träger und
• e) gegebenenfalls Waschen, Trocknung, Calcinierung, Zerkleinerung und/oder Klassierung des Substrates,

wobei die Strukturierung des Trägers derart gewählt ist, dass das abgetrennte Substrat bei Bestrahlung mit elektromagnetischer Strahlung retroreflektiv ist.In a further embodiment of the method according to the invention, the structured substrate is produced on a support. The present invention accordingly also provides processes for the preparation of effect pigments comprising the process steps:

• a) application of a film comprising a substrate precursor to a structured support,
• b) solidification of the film by drying,
• c) development of a substrate by chemical reaction from the substrate precursor,
• d) separation of the substrate from the structured support and
• e) optionally washing, drying, calcining, comminution and / or classification of the substrate,

wherein the structuring of the carrier is selected such that the separated substrate is retroreflective upon irradiation with electromagnetic radiation.

• a) Aufbringung eines Films enthaltend einen Substratprecursor auf einen strukturierten Träger,
• b) gegebenenfalls Verfestigung des Films durch Trocknung,
• c) ein- oder mehrmaliges Wiederholen der Schritte a) und b), wobei jeweils voneinander verschiedene Substratprecursor eingesetzt werden,
• d) Verfestigung des Films durch Trocknung,
• e) Entwicklung eines Substrates durch chemische Reaktion aus dem Substratprecursor,
• f) Abtrennung des Substrates vom strukturierten Träger und
• g) gegebenenfalls Waschen, Trocknung, Calcinierung, Zerkleinerung und/oder Klassierung des Substrates,

wobei die Strukturierung des Trägers derart gewählt ist, dass das abgetrennte Substrat bei Bestrahlung mit elektromagnetischer Strahlung retroreflektiv ist, ebenfalls Gegenstand der vorliegenden Erfindung.In addition, processes for the preparation of effect pigments comprising the process steps are:

• a) application of a film comprising a substrate precursor to a structured support,
• b) optionally solidifying the film by drying,
• c) repeating steps a) and b) one or more times, using mutually different substrate precursors,
• d) solidification of the film by drying,
• e) development of a substrate by chemical reaction from the substrate precursor,
• f) separation of the substrate from the structured support and
• g) optionally washing, drying, calcination, comminution and / or classification of the substrate,

wherein the structuring of the carrier is selected such that the separated substrate is retrorefleective upon irradiation with electromagnetic radiation, also subject of the present invention.

In this particular embodiment be in step c) steps a) and b) one or more times. hereby Substrates can be made of mutually different substrate precursors produce, e.g. first by using water glass and further by using alkoxysilanes. Alternatively, effect pigments based on substrates can be used from material mixtures, e.g. Silicon / aluminum, silicon / boron, aluminum / boron mixtures. The mixture can be used as a gradient or in the form of discrete layers available. In the latter case, the implementation of an intermediate drying according to step b) preferred.

analog Tape methods using unstructured tapes are known in the art and e.g. in WO 93/08237 and mentioned there References, which are hereby incorporated by reference in this application are included.

Of the structured carrier in the present invention may consist of all common materials, such as. Metals, plastics or other materials. Preferably is the carrier made of plastics, such as Polyethylene terephthalate, polyesters or Polyacrylates and is in the form of an endless belt that the Has structuring. Preference is given to polyethylene terephthalate used as a band material. The structuring of the structured carrier is a negative image of the structure of the effect pigment to be produced. The preparation of a suitable carrier usually also takes place by imprinting by means of a stamping tool. Here, the embossing tool but a positive image of the desired Structuring on. With this embossing tool is then the in the inventive method structured carriers to be used, which then has a negative image. The to be produced with the help of this carrier Pigments then show the desired Structuring as a positive.

Corresponding embossing tools are available in a variety of ways that are generally available to those skilled in the art. Thus, suitable embossing tools can be obtained by microstructuring or nanostructuring, for example by means of focused ion beams, by holographic methods or by laser structuring. Methods for producing correspondingly suitable embossing tools can be found, for example, in US 2003/0223830, US 2003/0133194, US 2003/0035231, US 2003/0058553, US 2003/0088946 or US 2003/0133194. Examples of the preparation of the structured supports can be found inter alia in WO 95/11464, US 5,691,846 , US 2004/0130057 or US 6,746,567 ,

When Substrate precursors in the above-mentioned methods may preferably solutions or suspensions containing one or more inorganic or organic compounds of the elements silicon, aluminum, boron, titanium, Zirconium and / or iron are used. As inorganic compounds can the corresponding salts, e.g. Halides, nitrates, sulfates, Phosphates, oxides or oxide hydrates, but also borates, aluminates and / or silicates be used. Organic compounds can e.g. alkoxy be the respective elements. Preferably, the substrate precursor contains inorganic Compounds of the elements silicon and / or aluminum and in particular Silicates, with water glass being particularly preferred.

Farther For example, the substrate precursor can be a network former, preferably in the form of soluble Salts, e.g. Aluminates and / or bristles that are beneficial on education and stability affect the substrates. Preferred network formers are sodium aluminate and / or sodium borate. The proportions of the network formers amount 0.1-30 Wt .-%, preferably 1-20 Wt .-%, based on the substrate.

When Wetting and wetting agents to improve the wetting of the structured carrier All the wetting agents known to the person skilled in the art come with the substrate precursor in question, which may be ionic and nonionic. Neither the type still the amount of wetting agent added is critical, but In general, the proportion of wetting agent is a maximum of up to 2% by weight, based on the substrate precursor.

On the structured carrier a film containing the Substratprecusor is applied, wherein the amount of deposited substrate precursor that was later obtained Thickness of the substrate can be varied. The application of the film can according to the above described band method, but also on alternative methods such as e.g. the immersion casting process be applied. Preferably, the resulting film is so thick that the structured carrier Completely and consistently covered with the film. The film features in this preferred form in Direction of the structured vehicle an image of the structuring and on the structuring opposite Side a smooth surface on.

The drying initiated chemical reaction leads to the development of a solid, structured substrate. The chemical reaction is preferably hydrolysis and condensation reactions, the leads to a crosslinking of the substrate precursor.

The Separation, washing, drying, calcination, comminution and / or classifying the method according to the invention the for the expert Methods such as e.g. are also described in WO 93/08327 and can in expert Be adapted to the respective system. Preferably the substrate by means of a liquid or gas jet separated. In this process step it can already come to a crushing of the substrates. Furthermore the comminution may also be carried out by grinding, e.g. by means of a ball mill. Other comminution methods or mills are well known to the person skilled in the art and can also be used. The classification is for size fractionation the pigments obtained and can be removed by sedimentation, decantation, Air classification and / or screening, depending on the desired grain size and size distribution.

retroreflective Pigments that are structuring on both sides of the platelets show are also produced by the above method. You can do this For example, structured substrates prepared by the tape method described and then structuring by embossing are applied on the unstructured side. Alternatively, pigments structured on both sides can be applied on both sides Produce embossing, the imprint the two sides simultaneously, e.g. by use of opposite structured rolls, or in successive steps can. It should be noted that the structuring each against each other offset occurs, that is, the areas of the surfaces, which are structured on one side, must be on the opposite Page unstructured and vice versa.

In a further embodiment, the structured carriers can have an additional superstructure for generating predetermined breaking edges. This superstructure has a circular or elliptical shape or is in the form of polygons V _n , with
n = the number of corners and
n ≥ 3.

The superstructure generates by predetermined elevations of individual edges in the structure predetermined breaking edges in the later effect pigments ( 3 ). In the method according to the invention, the comminution preferably takes place at the predetermined breaking edges occurring due to the over-structuring. For the purposes of this application, the latter are those edges which protrude into the substrate film due to the structuring. At these edges, the substrate is thinner than at the remaining locations of the substrate film. By structuring the carrier thus predetermined breaking points are introduced into the substrate. By external action such as a liquid jet in the separation of the substrate, it breaks at the predetermined breaking points and effect pigments of uniform shape and size are obtained.

In a further embodiment of the method according to the invention, the substrate can be coated with one or more layers comprising metal oxides, metal oxide hydrates, metal suboxides, metals, metal fluorides, metal nitrides, metal oxynitrides or mixtures of these materials. Examples of such materials have previously been described in the construction of the pigments of the invention. The coating can be carried out both wet-chemically, by means of a sol-gel process but also via CVD or PVD processes. The coating preferably takes place wet-chemically or by means of CVD or PVD processes and very particularly preferably wet chemically. In the wet-chemical processes, both precipitation reactions, for example corresponding metal oxides, and reduction reactions with deposition of, for example, metals on the surface of the effect pigments are suitable. Examples of the said processes and the compounds and precursors which can be used are found, for example, in US Pat EP 0 141 173 . EP 0 332 071 . DE 19 51 697 . DE 23 13 332 . DE 40 09 567 . EP 0 645 851 . EP 0 106 235 and EP 0 753 545 , The coating can completely cover the substrates or can be applied only partially on one or more sides. If, for example, the substrate is separated off from the carrier in accordance with the method according to the invention and then provided with a subsequent coating, in particular in the case of the wet-chemical coating, the coating material is preferably completely covered with the layer material. In contrast, the one or more layers can also be applied to the substrate on the carrier, which is subsequently separated from the carrier as a coated substrate. In this case, there is an occupancy of the substrates on only one side of the substrates, namely the side facing away from the carrier. By appropriate selection of the sequence of subsequent coating and separation from the carrier, the achievable optical effects can be further adapted to the needs of the user. In particular, the application of metal layers in combination with the substrate can lead to particularly interesting optical effects. Preferably, the application of the one or more layers after the separation of the substrate from the carrier.

In addition, in an inventive method also in addition as an outer layer, an organic coating can be applied. Examples of such coating methods can be found inter alia in EP 0 632 109 . US 5,759,255 . DE 43 17 019 . DE 39 29 423 . DE 32 35 017 . EP 0 492 223 . EP 0 342 533 . EP 0 268 918 . EP 0 141 174 . EP 0 764 191 , WO 98/13426 or EP 0 465 805 , Examples of organic coatings and the associated advantages have already been described in advance in the construction of the pigments according to the invention. The process step of applying the organic coating can be connected directly to the other steps of the method according to the invention.

The effect pigments of the invention are versatile. Accordingly, the use of the pigments of the invention in coatings, cosmetics, paints, inks, inks, toners, in ceramic materials, glasses, Paper, in plastics, foils, in security printing, in security features in documents and passports, for food coloring, as Tracer or in drug coatings as well for the preparation of pigment preparations and dry preparations also the subject of the present invention.

in the In the case of cosmetics, the effect pigments according to the invention are suitable especially for Products and formulations of decorative cosmetics, e.g. Nail polishes coloring powders, lipsticks or eyeshadows, soaps, toothpastes etc. Of course can the effect pigments of the invention in the formulations also with any kind of cosmetic raw and Excipients are combined. These include u.a. Oils, fats, waxes, film formers, Preservatives and general application properties determining adjuvants, e.g. Thickener and rheological additives such as bentonites, hectorites, silica, ca silicates, gelatin, high molecular weight carbohydrates and / or surface-active adjuvants, etc. The effect pigments of the invention containing formulations belong to the lipophilic, hydrophilic or hydrophobic type. at heterogeneous formulations with discrete aqueous and non-aqueous Phases can the particles of the invention in each case contain only one of the two phases or over both Be distributed phases.

The pH values of the aqueous Formulations can between 1 and 14, preferably between 2 and 11 and particularly preferred between 5 and 8 lie. The concentrations of the effect pigments of the invention There are no limits in the formulation. You can - depending on Use case - between 0.001 (rinse-off products, e.g., shower gels) - 99% (e.g., gloss effect article for special Applications) are. The effect pigments of the invention can furthermore can also be combined with cosmetic active ingredients. Suitable active ingredients are e.g. Insect Repellents, UV A / BC protection filters (e.g., OMC, B3, MBC), Anti-aging agents, Vitamins and their derivatives (e.g., vitamins A, C, E, etc.), self-tanner (e.g. DNA, erythrolose, etc.) as well as other cosmetic agents, such as e.g. Bisabolol, LPO, ectoine, emblica, allantoin, bioflavanoids and theirs Derivatives.

When using the effect pigments in paints and coatings, all applications known to the person skilled in the art are possible, such as, for example, powder coatings, automotive coatings, printing inks for gravure, offset, screen or flexographic printing and for coatings in outdoor applications. The inventively pigmented coatings can be applied to moldings of any shape, which is not possible with the known from the prior art retroreflective films. Thus, even strongly three-dimensionally curved surfaces, such as balls, fenders, coated and can be equipped with a retroreflective effect. The fields of application are widely scattered and include applications in passive safety, such as street signs, number plates, Reflectors for clothing or in road markings. The paints and paints can be, for example, radiation-curing, physically drying or chemically curing. For the production of printing inks or liquid coatings is a variety of binders, for example based on acrylates, methacrylates, polyesters, polyurethanes, nitrocellulose, ethylcellulose, polyamide, polyvinyl butyrate, phenolic resins, maleic resins, starch or polyvinyl alcohol, amine resins, alkyd resins, epoxy resins, polytetrafluoroethylene, Polyvinylidene fluorides, polyvinyl chloride or mixtures thereof, in particular water-soluble types. The paints may be powder paints or water- or solvent-based paints, the selection of the paint components is subject to the general knowledge of the skilled person. Common polymeric binders for powder coatings are, for example, polyesters, epoxies, polyurethanes, acrylates or mixtures thereof.

Furthermore can the effect pigments of the invention used in films and plastics, e.g. in agricultural films, infrared-reflective films and discs, gift foils, plastic containers and moldings for all known in the art applications. Infrared reflecting films containing effect pigments according to the present invention Invention are suitable for Applications in the field of thermal insulation and thermal management. The retroreflective coating appears except at looking at it with a light source pointing towards the viewer is gray-black, but is for the entire incident radiation IR and VIS highly reflective. Similar Effects can only be achieved with highly reflective surfaces (reflection) or white, highly dispersive surfaces to reach. By the property, infrared radiation to its starting point back to radiate, can retroreflective pigments also for coating heat insulators be used. This is the heat radiation, as opposed to a simple mirroring, reflected directly back to the source. Suitable plastics are all common plastics for incorporation the effect pigments according to the invention, e.g. Duromeric or thermoplastic plastics. The description the application possibilities and the applicable plastics, processing methods and additives can be found e.g. in RD 472005 or in R. Glausch, M. Kieser, R. Maisch, G. Pfaff, J. Weitzel, Pearlescent Pigments, Curt R. Vincentz Verlag, 1996, 83 ff., The disclosure content of which includes here is.

coatings containing effect pigments according to the present invention Invention are also advantageously suitable as projection surfaces. For projection surfaces, such as they are used for example in cinemas and video projection systems, a coating with retroreflective pigments is very advantageous. On the in the manufacturing process adjustable geometrical errors, i. the Deviation of the angles within the cube corners of the ideal value 90 °, can also the emission characteristics adapted to the necessary conditions become. Across from A diffusely reflecting screen becomes significant for the viewer get brighter projections. Also opposite projection screens the with glass ball coatings are a clear get a brighter projection image.

Furthermore the effect pigments of the invention are suitable also for the use in security printing and in safety-relevant features for e.g. tamper-proof Cards and passes, such as Tickets, identity cards, Banknotes, checks and check cards as well as other forgery-proof documents. In the food sector can the effect pigments for coloring Be used for food. For pigmentation of coatings in medicaments such as. Tablets or dragées are the effect pigments of the invention also usable.

The effect pigments according to the invention are also suitable for use in blends with organic dyes and / or pigments, such as transparent and opaque white, colored and black pigments and platelet-shaped iron oxides, organic pigments, holographic pigments, LCPs (Liquid Crystal Polymers) and conventional transparent, colored and black luster pigments on the basis of metal oxide-coated platelets based on mica, glass, Al ₂ O ₃ , Fe ₂ O ₃ , SiO ₂ , etc. The effect pigments of the invention can be used in any ratio with commercially available pigments and fillers be mixed.

When fillers are e.g. naturally and synthetic mica, nylon powder, pure or filled melanin resins, Talcum, glasses, Kaolin, oxides or hydroxides of aluminum, magnesium, calcium, zinc, BiOCl, barium sulfate, calcium sulfate, calcium carbonate, magnesium carbonate, Carbon, as well as physical or chemical combinations of these substances to call. In terms of the particle shape of the filler there are no restrictions. It can meet the requirements according to e.g. platy, spherical or acicular be.

The effect pigments according to the invention are furthermore suitable for the preparation of flowable pigment preparations and dry preparations containing one or more particles according to the invention, binders and optionally one or more additives. Dry preparations are also to be understood as preparations which contain from 0 to 8% by weight, preferably from 2 to 8% by weight, in particular from 3 to 6% by weight, of water and / or a solvent or solvent mixture. The dry preparations are preferably in the form of pellets, granules, chips, sausages or briquettes and have particle sizes of 0.2-80 mm. The dry preparations are used in particular in the production of printing inks and in cosmetic formulations.

A special application the effect pigments of the invention consists in its use as a tracer in mixtures with other organic and / or inorganic colorants, e.g. for marking colors, Paints, printing inks, plastics, textiles, cosmetic formulations, Food, pharmaceutical products, ceramic materials, glasses, Paper, safety materials, dry preparations, pigment preparations. This is especially true for Effect pigments according to the present invention Invention with uniform shape and size.

tracer are often used as identification means in modern products used. With their help, the authenticity of a product is demonstrated or the origin of a product can be reconstructed. Common tracers are based on fluorescent, radioactive or luminescent Substances to be protected Product may be added as a powder, suspension or liquid. These substances are often toxicologically and environmentally questionable or need for their traceability special equipment and devices.

The effect pigments of the invention can the colorants to be marked or products made therefrom, such as. Paints, powders, paints or suspensions under application all methods known in the art are added. The amount of the tracer in the product to be labeled is usually ≦ 5% by weight, based on the labeled product and preferably <2 wt .-% and completely particularly preferably 0.1-1% by weight.

ever according to size or Geometry of the effect pigments according to the invention The tracer in mixtures with pigments of other form can be very simple by means of a microscope or with the scanning electron microscope be detected. Chemically and toxicologically, these behave Tracers like other effect pigments and are thus chemically inert and toxicologically harmless. Particularly advantageous is the mixing the pigments of the invention with unstructured effect pigments, the same layer structure, but not the same shape or size. As for this Application to the customer requirements specially adapted effect pigments of the invention commercially not available are sufficient copy protection of the mixture to be marked guaranteed.

The full Disclosure of all the above-mentioned patent applications, patents and publications is incorporated by reference in this application.

The The following examples are intended to explain the invention in more detail without, however, limiting it.

Example 1: Preparation the pigment base

On one with triple mirror geometries (edge length 5μm) in hexagonal faceting provided structured film made of PET, is by dip casting a diluted one aqueous sodium silicate solution (about 20% sodium orthosilicate), which as wetting agent 0.1 wt .-% Contains Triton X-100, evenly distributed. The soda water glass film is dried in a circulating air oven at 50 ° C. and separated from the film. Subsequently, the obtained solid at 700 ° C annealed and gently crush the coarse pigment particles to 20-100 μm in a mortar.

Example 2: Mirroring the pigment base

The obtained in Example 1 is in a freshly prepared 0.1 molar ammoniacal silver nitrate solution suspended. To the suspension At room temperature, a 10 wt.% Glucose solution under gentle stirring given. This is due to the silver mirror reaction known to those skilled in the art released silver beats settling on the pigment particles. The mirrored pigment particles are filtered off with suction and washed with demineralized water

Example 3: Processing mirrored retroreflective pigments

100 mg of the pigment particles obtained in Example 2 are slowly stirred into 5 ml of Beckopox EP 140 (unmodified liquid epoxy resin from UCB). 0.5 ml of triethylenetetramine as curing agent are now added to the epoxy resin mixed with pigment particles and homogeneously distributed with the resin. Immediately after homogenization, black anodized aluminum test panels are lightly brushed with the resin / hardener / pigment mixture. To accelerate the curing process, the coated test specimens are stored at 85 ° C for 2 hours. The test panels show in the irradiation with a light source in a darkened room, in a wide angular range significantly retroreflective properties. It is important in the visual assessment that observers, light sources and test specimens on an imaginary line are located.

Example 4: Processing non-mirrored retroreflective pigments

100 mg of the pigment particles obtained from Example 1 are in the same As in Example 3 incorporated into the epoxy resin and the hardener. The Be test specimen processed in the same way. The resulting coating shows also retoreflective properties. The effect is however less strong than in example 3. The reason for this is in the relatively small difference of the refractive indices (delta n = ca. 0.1), which only at certain angles to a total reflection the interface Paint (high refractive index) leads to pigment (lower refractive index).

By higher refractive index Paints obtained, for example, by additions of high-index nanoparticles can be let yourself significantly increase retroreflection. In the same way one works Coating the pigment particles with a low-refractive layer, for example, magnesium fluoride. In this way it is possible the Retroreflection by total reflection of the paint at the interface to the Significantly increase pigment. It is advantageous here that pigment particles without metallic coating can be used.

Claims (22)

Effect pigments based on structured platelet-shaped substrates, characterized in that the effect pigments are retroreflective when irradiated with electromagnetic radiation. Effect pigments according to Claim 1, characterized that the surface the structured platelet-shaped substrates arranged from regularly Triple mirrors exists. Effect pigments according to claim 2, characterized in that that the triple mirrors trigonal, tetragonal, square, pentagonal or hexagonal faceted Effect pigments according to claim 2 or 3, characterized in that the triple mirrors are trigonal, tetragonal, square, pentagonal or hexagonal are arranged. Effect pigments according to claim 2 or 3, characterized characterized in that the edge length the triple mirror 1 to 25 microns is. Effect pigments according to one of claims 1 to 4, characterized in that the platelet-shaped substrates of metal oxides, Metal oxide hydrates, metal suboxides, metals, metal fluorides, metal nitrides, Metal oxynitrides, polymers or mixtures of these materials consist. Effect pigments according to Claim 1, characterized in that the platelet-shaped substrates consist of glass, synthetic mica, Al ₂ O ₃ , SiO ₂ , TiO ₂ , ZrO ₂ , iron oxides, aluminum, titanium or alloys, magnesium fluoride, calcium fluoride or mixtures of these materials , Effect pigments according to one of claims 1 to 6, characterized in that they additionally with one or more containing transparent, semi-transparent and / or opaque layers Metal oxides, metal oxide hydrates, metal suboxides, metals, metal fluorides, Metal nitrides, metal oxynitrides or mixtures of these materials are coated. Effect pigments according to claim 8, characterized in that that extra Coating on at least one side of the structured substrates is present. Effect pigments according to claim 8, characterized in that that extra Coating the structured substrates wrapped. Effect pigments according to claim 8, characterized in that that the one or more transparent, semi-transparent and / or opaque layers containing metal oxides, metal oxide hydrates, metal suboxides, Metals, metal fluorides, metal nitrides, metal oxynitrides and / or Mixtures of these materials with colorants and / or elements are doped. Effect pigments according to one of claims 1 to 11, characterized in that the effect pigments have a uniform Have shape and size. Effect pigments according to one of claims 1 to 12, characterized in that additionally as an outer layer of an organic Coating is applied. Process for the preparation of effect pigments according to claim 1, characterized in that a structuring in a platelet-shaped substrate by means of a structured body is coined being the structuring of the body chosen like that is that embossed Substrate upon irradiation with electromagnetic radiation retroreflective is. Process for the preparation of effect pigments according to claim 1 comprising the process steps: a) application of a film comprising a substrate precursor to a structured support, b) solidification of the film by drying, c) development of a substrate by chemical reaction from the substrate precursor, d) separation of the substrate from the structured support and e) optionally washing, drying, calcining, comminution and / or classification of the substrate, wherein the structuring of the support is selected such that the separated substrate is retrorefleqive upon irradiation with electromagnetic radiation. Process for the preparation of effect pigments according to Claim 1, comprising the method steps: a) application of a film containing a substrate precursor on a structured Carrier, b) optionally solidification of the film by drying, c) a or repeating steps a) and b) several times, each time different substrate precursors are used, d) Solidification of the film by drying, e) Development of a Substrate by chemical reaction from the substrate precursor, f) Separation of the substrate from the structured support and g) if necessary Washing, drying, calcination, comminution and / or classification of the substrate, wherein the structuring of the carrier is such is chosen, that the separated substrate upon irradiation with electromagnetic Radiation is retroreflective. Method according to claim 15 to 16, characterized in that the structured carrier a endless tape is. Method according to claim 15 to 17, characterized in that the structured carrier a additional superstructure for generating predetermined breaking edges. Method according to one the claims 14 to 18, characterized in that the effect pigments in addition to one or more transparent, semi-transparent and / or opaque Layers containing metal oxides, metal oxide hydrates, metal suboxides, Metals, metal fluorides, metal nitrides, metal oxynitrides or mixtures these materials are coated. Method according to claim 19, characterized in that the coating with one or more Layers wet-chemically, by sol-gel method or by CVD or PVD method. Method according to one the claims 14 to 20, characterized in that additionally as an outer layer of an organic Coating is applied. Use of effect pigments according to claim 1 in coatings, cosmetics, paints, inks, inks, toners, in ceramic materials, glasses, Paper, in plastics, foils, in security printing, in security features in documents and passports, for food coloring, as Tracer or in drug coatings as well for the preparation of pigment preparations and dry preparations.