WO2006018094A1 - Pigments based on cylinders or prisms - Google Patents

Abstract

The invention relates to pigments which are based on cylinders or prisms, the height of the cylinders or prisms ranging from 100 nm to 500 ?m and the diameter of the base of the cylinders or the shortest diagonal of the base of the prisms ranging from 100 nm to 500 ?m, whereby the cylinders or prisms consist of tubes and/or rods arranged one next to the other and in a lying position with respect to the height axis of the cylinders or prisms. The invention also relates to methods for preparing said pigments and to the use thereof in paints, lacquers, printing inks, plastic materials, films, cosmetic or pharmaceutical formulations, ceramic materials, glasses, paper, for laser marking, in security materials, in thermally insulating materials, for dyeing seeds, for coloring food, in coatings for drugs, in dry preparations, in pigment preparations, for analytical purposes, as switches or as tracers.

Description

 Pigments based on cylinders or prisms

The present invention relates to pigments based on cylinders or prisms, wherein the height of the cylinders or prisms is 100 nm to 500 μm and the diameter of the base area of the cylinders or the shortest diagonal of the prism base is 100 nm to 500 μm and the cylinders or prisms of juxtaposed and lying in the direction of the height axis of the cylinder or the prisms tubes and / or rods. Furthermore, the present invention relates to processes for the preparation of these pigments and their use in paints, coatings, printing inks, plastics, films, cosmetic or pharmaceutical formulations, ceramic materials, glasses, paper, for laser marking, in safety materials, in thermal protection, for seed coloring, food coloring , in drug coatings, in dry preparations, in pigment preparations, for analytical purposes, as a switch or as a tracer.

The color design of everyday objects has always been of great importance. In addition to the dyes, pigments are an important source of colorants that can be used to color materials and objects. In many cases, the pigments are inorganic pigments, e.g. White, colored or effect pigments. Especially the latter are increasingly gaining economic importance, e.g. in automotive coatings, powder coatings, printing or cosmetics.

In addition to the inherent color of the effect pigments, additional effects such as e.g. Gloss, interference phenomena or diffraction phenomena play a role in the choice of pigments.

In order to meet the requirements of the manufacturers in the above-mentioned areas and to always allow new color creations, there is a ongoing need for new pigments. These new pigments should be easy to prepare, stable, ecologically and toxicologically harmless or chemically inert and should allow special colors and effects in the applications mentioned.

The present invention therefore an object of the invention to provide novel pigments that can be displayed in a simple manner.

Surprisingly, it has been found that pigments according to the present invention fulfill this requirement profile. The present invention accordingly provides pigments based on cylinders or prisms, wherein the height of the cylinders or prisms is 100 nm to 500 μm, and that the diameter of the base area of the cylinders or the shortest diagonal of the base area of the prisms is 100 nm to 500 μm and the cylinders or prisms consist of juxtaposed tubes and / or rods lying in the direction of the height axis of the cylinders or of the prisms. The present invention furthermore relates to processes for the preparation of pigments based on cylinders or prisms and to the use of the pigments of the invention in paints, coatings, printing inks, plastics, films, cosmetic or pharmaceutical formulations, ceramic materials, glasses, paper, for laser marking. in safety materials, in thermal protection, for seed coloring, for coloring food, in drug coatings, in dry preparations, in pigment preparations, for analytical purposes, as a switch or as a tracer.

The pigments of the invention are novel alternatives to the previously known pigments and can be used in many ways. Due to the great variability of the microstructure of the pigments and the materials used in the pigments, the pigments can be adapted for the respective application with regard to their optical properties become. Thus, by suitable choice of the size dimensions of the tubes and / or rods in relation to the size dimensions of the pigments, suitable pigments can be provided for each wavelength range of the light. For example, by interacting with visible light, the pigments can show color effects that are suitable for use in

Objects of everyday use can be used advantageously. In many cases, the pigments of the invention show opalescence, which gives the articles a particularly visually appealing appearance. Moreover, with appropriately adjusted pigments, interaction with non-visible radiation, e.g. UV radiation or infrared radiation, occur. This interaction can be used as a security feature, since the presence of the pigments of the invention can be detected by irradiation with light of appropriate wavelength. In addition, pigments are toxicologically and ecologically harmless and accessible in the simplest case by methods established in the art. Thus, the pigments can be obtained by the established in the art top-down approach, that is, the structures are very easy to produce macroscopically, for example, by bundling tubes or rods with diameters in the cm range in the desired, arbitrary form. By thermal drawing processes, these systems can then be accurately and reproducibly reduced to structures in the nanometer range. Due to this "mechanical nanotechnology", the adjustment, planning and reproducibility is much better than in the case of the ordered nanostructures produced according to previously customary methods.

The pigments of the invention are based on cylinders or prisms. The cylinders or prisms may be straight or oblique, preferably straight. If the pigments are those based on prisms, they may have a base area in the form of a polygon V _n with n as the number of corners of the polygon V _n and n> 3. Preferably n is equal to 3, 4, 5, 6, 7, 8, 9 or 10. The Edge lengths of the polygons V _n can be the same size or unequal size, that is, the prisms can be regular or irregular. Preferably, the edge lengths of the polygons V _{n are the} same size, so that they are pigments based on regular prisms.

The height of the prisms or cylinders and thus the length of the pigments can be 100 nm to 500 μm, preferably in the range of 5 to 300 μm and very particularly preferably in the range of 0.5 μm to 50 μm.

The diameter of the base area of the cylinders or the shortest diagonal of the base area of the prisms can be 100 nm to 500 μm, preferably 2 μm to 200 μm and very particularly preferably 0.5 μm to 70 μm. Ideally, the diagonal of the base of the prisms means the straight line passing through two opposite corners of the prism

Polygon V _n runs. In addition, it is also possible that the diagonal is the line that intersects two opposite edges of the polygon V _n at right angles.

The prisms or cylinders consist of tubes and / or rods, the prisms or cylinders consisting of an array of at least two tubes and / or rods. Preferably, there are a plurality of tubes and / or rods, wherein the upper limit of the number per se is not limited. Preferably, the prisms and / or cylinders are made of tubes. The tubes can also have the shape of a cylinder or any prism, in the simplest case are cylindrical tubes. The geometries of the cylinder or prism outer walls of the tubes and the corresponding inner walls are independent of each other. For example, a tube in the form of a prism having a hexagonal geometry with respect to the outside of the prism wall may have a round geometry with respect to the prism inner wall and vice versa. Regarding the individual Geometries or the individual combinations there are no restrictions. Preferably, the tubes are prisms with trigonal, tetragonal, hexagonal, octagonal or decagonal, in particular with hexagonal geometry of the base surface for the outside and with round geometry for the inside. Tubes of the preferred geometry provide in a particularly simple manner pigments of the invention based on prisms with a hexagonal base. The surface of the tubes and / or rods or the prisms or cylinders can also be structured. The structuring can be based, for example, on regularly arranged grooves, spheres or pyramids. Due to the regular structuring, additional diffractive effects can be produced, as are known in the case of pigments, for example from WO 03/053674 and WO 03/102084, the disclosure content of which is hereby included by reference.

The difference in refractive indices between the wall material of the tubes and the tube interior, preferably air, leads to the preferred optical effects of the resulting pigments. The tubes and / or rods may be in the form of a densest packing, preferably a hexagonal closest packing. A hexagonal closest packing is most easily achieved by packing hexagonal tube prisms or cylindrical tubes. But it can also be targeted flaws are generated, that is, individual tubes and / or rods may be missing in the arrangement. Defects of this kind can be caused by diffraction or

Interference phenomena cause special color effects. The tubes and / or rods are preferably fixedly connected to one another, the connection taking place in particular by adhesion or by a fusion of the outer walls of the tubes and / or rods to one another. In this way, bundles of tubes and / or rods are obtained, which dictate the shape of the prisms or cylinders. The tubes and / or rods of the cylinders or prisms can be made of glass, SiO ₂ , B ₂ O ₃ , Al ₂ O ₃ , metals, plastics or mixtures of these materials. Alternatively, the cylinders or prisms as well as tubes and / or rods may contain these materials, any combination of materials being conceivable. For example, tubes and / or rods of glass or SiO _{2 may be combined} with tubes and / or rods of metals. The tubes and / or rods are preferably made of glass, SiO ₂ or metals.

The outer diameters of the tubes and / or rods in the pigments according to the invention can vary between 20 nm and 250 μm, preferably between 70 nm and 2 μm and in particular between 90 nm and 800 nm. In the case of tubes, the diameters of the tube walls can be enclosed pores are 1 nm to 2 microns, in particular 20 nm to 1 micron. The distances of the pore centers are in the range of 1.5 nm to 2.5 μm. Moreover, the diameters of the tubes and / or rods or the pores in the pigments enclosed by the tube walls can be the same size or not the same size. In this way, the variety of achievable effects can be extended. Due to interference or diffraction effects, pigments of this type can show an interesting play of colors that is similar in appearance to that of opals.

Any glass known to those skilled in the art, eg E glass, A glass, E CR glass, C glass, D glass, R glass or S glass, is suitable as the glass. Glasses of these types are known and described, for example, in Ullmann's Encyclopedia of Industrial Chemistry, under Fibers, Synthetic Inorganic, Glass Fibers. In addition to the glasses, SiO _{2 is} also a preferred material. Both the glasses and SiO ₂ may be doped with elements, eg germanium, gold, silver, platinum, lead, boron, silicon,

Lanthanides, actinides, trivalent cations of rare earth metals, such as Eu ³⁺ , fluorine and / or phosphorus, with respect to the doping no - J -

Restrictions exist. By doping the glass or SiO ₂ , the refractive properties of the materials can be varied and adapted to the needs.

The plastics may preferably be selected from the group of

Polyacrylates, polycarbonates, polystyrenes, siloxanes, fluoropolymers, polyesters and / or mixtures thereof. Suitable fluoropolymers are, for example, fluoroacrylates, fluoroacrylate esters, fluorinated polyimides, polytetrafluoroethylene or fluorosilicones. Like the glasses, the plastics can be doped with elements in order to vary the optical properties of the plastics in particular.

Suitable metals for the tubes and / or rods of the cylinders or prisms are, for example, germanium, gold, platinum, silver, lead or silicon.

In one embodiment of the present invention, the cylinders or prisms include tubes and / or rods of glass and metals. The tubes and / or rods of metals may be statistically distributed or ordered over the prisms or cylinders. With both variants, additional effects can be achieved, which are based on the reflection of the light at the tubes and / or rods made of metals. In the case of a defined arrangement of tubes and / or rods made of metals, any type of arrangement is included in the present invention. For example, the tubes and / or rods may be made of metals along one or more diagonals of the base of the cylinders or prisms, the diagonals not having to pass through the base center. Ideally, the diagonal of the base of the prisms means the straight line passing through two opposite corners of the polygon V _n . In addition, it is also possible that the diagonal is the line that intersects two opposite edges of the polygon V _n at right angles. The diagonals can be parallel and not parallel to each other - S -

be arranged. By incorporating tubes and / or rods of metal along one or more diagonals, additional levels acting as mirrors are created which can further increase the gloss and variety of effects. By an appropriate arrangement of several diagonals, the desired effect can be independent of the

Alignment of the pigment can be achieved in the application medium.

In a further embodiment, the tubes and / or rods or the resulting bundles thereof can be 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, Alumina, alumina hydrate, silica, silica oxide, iron oxide, tin oxide, ceria, zinc oxide, zirconia, chromia, titania, especially titania, titania hydrate and mixtures thereof, e.g. Ilmenite or pseudobrookite. As metal suboxides, for example, the titanium suboxides can be used. Suitable metals are e.g. Chromium, aluminum, nickel, silver, gold, platinum, lead, germanium, titanium, copper or alloys, 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 tubes and / or rods. You can also continue

Multilayer structures of high and low refractive index metal oxide, metal oxide hydrate, metal or metal fluoride layers are present, wherein preferably alternate high and low refractive 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 tubes and / or rods. The order of the high and low refractive layers can be adapted to the material of the tubes and / or rods, to include the tubes and / or rods 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 inorganic color pigments such as colored metal oxides, eg 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 else

Carmine or elements such as e.g. Yttrium or antimony. Tubular and / or rod-based pigments containing these layers exhibit a high color diversity with respect to their body color and, in many cases, can show an angle-dependent change of color (color flop) due to interference.

The outer layer on the tubes and / or rods in a preferred embodiment is a high refractive index metal oxide. This outer layer may additionally be part of a layer package on the abovementioned layer packages or, for high-index carriers, 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.

In the case of tubes, these can be attached to the prism or

Cylinder base surfaces closed or open, preferably closed so that solvents or other compounds when incorporated into Formulations or applications can not penetrate into the tubes. In this way, a change in the refractive index differences between the tube materials and the component enclosed in the tubes, eg air, is prevented. This ensures an unchanged color and Effektgestallung when incorporated into the corresponding

Application systems.

However, the cavities between the rods and / or tubes or in the tubes can also be filled with any substances, the degree of filling need not be complete. The infiltration or impregnation of the cavities with substances can be carried out from the gas phase or in solution or dispersion. The cavities may be infiltrated, for example, from the gas phase with vapors of metals or gaseous precursors for metals, semiconductors (eg III-V semiconductors such as GaN, AlN, InN or mixed crystals thereof, GaAs, InAs, InP) or insulators. Furthermore, the cavities can be filled by means of solution impregnation by utilizing capillary effects, for example with dispersed nanoparticles or soluble precursors for metals, semiconductors or insulators. A filling of the cavities with phosphors is also conceivable, for example, with Eu ³⁺ : Y ₂ θ ₃ , wherein the absorption and

Emission properties of the phosphors can be influenced by the modulated difference in the refractive index of the arrangement of the tubes and / or rods. In addition, the cavities can be loaded with dyes, for example with laser-active dyes for the construction of microlasers. Suitable dyes are known in the art and can be used in the context of the present invention. In addition, the cavities can be loaded with liquid crystalline mixtures. As a result, the optical properties can be influenced by external influences, such as by changing the temperature or by the influence of electrical or magnetic fields. For example, it is possible to realize pigments for switchable coatings in which the influence of external electric fields, the wavelength of the reflection colors shifted or the transparency can be changed.

In a further embodiment of the present invention, the pigments may additionally be coated with one or more transparent, semi-transparent 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 one or more transparent ones , 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 may be doped with colorants and / or elements. Examples and possible arrangements for the above-mentioned materials are already mentioned in advance.

Furthermore, the pigments according to the invention can be provided with a secondary coating. Suitable materials for the post-coating are, for example, organosilanes and / or polymers, wherein the said materials may be present mixed in one layer or separately in several layers.

Suitable organosilanes are, for example, silanes of the general formula

X _4-n- mZ-R _n (-BY) _rn

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 exist.

The organosilanes consist of an anchor group (X ₄ .. _n . _M Z), which can bind, for example, to the surface of the pigment, at least one hydrophobic group (R ₁ 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 choosing suitable functional groups, the organosilane can be adapted to the requirements. In addition, depending on the coating sequence, additional bonds between the pigment and the medium can be generated via the organosilane by reaction of the functional groups with corresponding functionalities in the application media. In a particular embodiment, the surface of the particles according to the invention is modified with a combination of organic functionalities adapted to the feed medium. For this purpose, the use of mixtures of different organosilanes is also suitable. The hydrophobicity of the particle surface can also be adjusted by integration of alkyl-containing coupling reagents, such as alkyl silanes. In addition to the organosilanes, it is also preferable to use their hydrolyzates and their homogeneous and heterogeneous oligomers and / or polymers which can likewise be used alone or in combination with the silanes already described. Particular preference is given to mixtures of different organosilanes, in particular with mutually different functional groups Y, the use of which ensures a particular range of application. Examples of organosilanes are propyltrimethoxysilane, propyltriethoxysilane, isobutyltrimethoxysilane, n-octyltrimethoxysilane, i-octyltrimethoxysilane, n-octyltriethoxysilane, n-decyltrimelhoxysilane, dodecyltrimethoxysilane, hexadecyltrimetrioxysilane, vinyltrimethoxysilane, octadecyltrimethoxysilane, preferably vinyltrimethoxysilane. As oligomerere, non-alcoholic

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 In addition, oligomeric vinylsilane and aminosilane hydrolyzate are suitable as organic coatings Functionalized organosilanes are, for example, 3-aminopropyltrimethoxysilane.

Methacryloxytrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, beta- (3,4-epoxycyclohexyl) -ethyltrimethoxysilane, gamma-isocyanatopropyltrimethoxysilane, 1,3-bis (3-glycidoxypropyl) -1,3,3,3-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. B. sold by the company. Sivento under the trademark Hydrosil ^® .

The polymers may be selected, for example, from the group of polyethers, polyesters, polyacrylates, polyvinylcaprolactams, cellulose, polystyrenes, polyvinyl alcohols, polyvinyl acetates, polysiloxanes, derivatives of the polymers mentioned or from mixtures thereof. The polymers are preferably crosslinked melamine-formaldehyde resins, LCST and / or UCST polymers or polymers with solvolyzable groups. The crosslinked melamine-formaldehyde resins are prepared by precipitating crosslinking melamine-formaldehyde resins on the pigments and then curing or crosslinking the melamine-formaldehyde resins. Resins formed. Further examples and embodiments of this process can be found in WO 03/074614.

LCST polymers or UCST polymers are polymers that are soluble in low or high temperatures in a solvent and in

Increasing or lowering the temperature and reaching the so-called LCST or UCST (lower or upper critical solution temperature) are separated from the solution as a separate phase. Such polymers are e.g. in the literature in "Polymere", H.G. Elias, Hüthig and Wepf-Verlag, Zug, 1996, pages 183 et seq.) In the case of polymers with solvolyzable groups, these are eliminated during solvolysis, the polymer precipitating on the substrate.

Suitable LCST polymers for the present invention are, for example, those described in WO 01/60926 and WO 03/014229. Particularly suitable LCST polymers are polyalkylene oxide derivatives, preferably polyethylene oxide (PEO) derivatives, polypropylene oxide (PPO) derivatives, olefinically modified PPO-PEO block copolymers, with acrylate-modified PEO-PPO-PEO triblock copolymers, and US Pat Polymers or their derivatives from the class of polymethyl vinyl ethers, poly-N-vinylcaprolactams, ethyl (hydroxyethyl) - celluloses, poly (N-isopropylacrylamide) and polysiloxanes. Particularly preferred LCST polymers are siloxane polymers or polyethers modified with olefinic or silanolic groups.

Suitable UCST polymers are in particular polystyrene, polystyrene copolymers and polyethylene oxide copolymers.

Preference is given to using LCST or UCST polymers with solvolyzable or functional groups which can undergo strong interactions and / or chemical bonds with the substrate or the application medium, for example the lacquer matrix. All known to the expert functional groups are suitable, especially silanol, amino, hydroxyl, olefin, hydroxyl, epoxy, acid anhydride and acid groups.

The LCST or UCST polymers preferably have molar masses in the range from 300 to 500,000 g / mol, in particular from 500 to 20,000 g / mol.

The post-coatings may additionally contain additives which additionally increase or decrease the chemical and / or mechanical stability of the pigments or impart UV-filtering properties or a coloring effect to the pigments. Suitable additives are e.g. Nanoparticles of all kinds, plasticizers, antioxidants, radical scavengers, UV filters, dyes, microtitanium or mixtures thereof. The additives are preferably admixed to the solution of the polymer as a dispersion, preferably using the same solvent as that of the polymer solution. By the inclusion of foreign matter, such as Nanoparticles, plasticizers or dyes, the properties of the pigments can be adapted to the individual needs of the user, or it can be several functionalities, such as. Coloring and UV filters, combined with each other in a variety of pigment.

The pigments of the invention are accessible in a simple manner. Thus, processes for the preparation of the pigments of the invention are also the subject of the present invention.

An embodiment of the method according to the invention comprises the following method steps: a) arranging tubes and / or rods in the form of cylinders or prisms, b) thermally drawing the cylinders or prisms obtained in a) so that the diameter of the base surface of the cylinders or the shortest Diagonal of the base of the prisms is 100 nm to 500 microns and c) reduce the cylinder or prisms obtained in b), so that the height of the cylinders or prisms is 100 nm to 500 μm

The cylinders or prisms obtained in process steps a) and b) may in the simplest case be so-called photonic crystals

Fibers act. Materials of this kind are known and methods of making photonic crystal fibers have been widely described, e.g. in WO 00/49436, EP 1 234 806, WO 03/012500, WO 02/101430, WO 03/086738, US 2002/0031319 or US 2003/0056550, the disclosure contents of which are hereby incorporated by reference in this application. The process variants mentioned in the individual disclosures, e.g. for the thermal drawing of the cylinders or prisms, are also used in the inventive method.

In a further embodiment of the method according to the invention, cylinder or prisms containing tubes and / or rods made of glass and metal are produced according to method step a) and processed according to the abovementioned method steps b) and c). Here, the tubes and / or rods of metal may be randomly distributed or distributed over the cylinders or prisms, preferably they are arranged along one or more diagonals of the base of the cylinder or prisms. By means of the processing steps b) and c), these structure patterns are correspondingly reduced and found again in the pigments thus produced.

In a further embodiment of the method according to the invention, the tubes and / or rods or the bundles resulting therefrom are provided in advance 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 thereof Coated materials. Corresponding materials are already in the description of the pigments according to the invention called. The coating can be carried out by all methods known to those skilled in the art, for example wet-chemically, by hydrolytic decomposition of suitable precursors or by CVD or PVD.

In addition, in a further embodiment of the process according to the invention, the pigments can be 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. Suitable materials and processes for their preparation are already mentioned in advance.

Furthermore, the pigments can be provided with a post-coating in a further embodiment of the inventive method. Suitable postcoats are already mentioned in the description of the pigments according to the invention. The application of the post-coating can be carried out by all methods known to the person skilled in the art, e.g. by precipitation in solution, by application in the melt, by solvolysis processes or by surface polymerizations.

The comminution mentioned in process step c) can likewise be carried out by customary methods, for example by milling, cutting and / or chopping. Process variants of this type and suitable apparatuses are known, for example, from US 4,319,506, US 2003/0231845, WO 02/42814, EP 0 229 500, EP 0 640 570, EP 0 563 687 or WO 03/097543. In the simplest case, the crushing is done by a hot cleaver, which splits the prisms or cylinders by melting. Furthermore, the crushing can also be done with a laser cutting beam. Furthermore, the tubes can be closed at the prism or cylinder bases. The tubes can be closed by melting, capping, grafting and / or by polymerization reactions. In the simplest case, the closure is carried out by melting the tube ends, which can be done simultaneously in the process step of crushing or separately in a separate step. Other process variants include the capping, the grafting or filling of the tubes at the ends, for example with polymerizable compounds, which at the tube ends by polymerization a solid bond with the

Enter tube ends. Examples of this can be found inter alia in US 2003/0068150, the disclosure of which is hereby incorporated by reference.

In a further embodiment of the method according to the invention, the cavities between the rods and / or tubes or in the tubes can be filled with substances. This can be done by subsequent infiltration or impregnation via the gas phase or by solution or dispersion loading. Examples of suitable substances are already mentioned in advance.

The pigments according to the invention are suitable for a wide range of applications because of their advantageous properties. The invention therefore also relates to the use of the pigments according to the invention in paints, lacquers, printing inks, plastics, films, cosmetic or pharmaceutical formulations, ceramic materials, glasses, paper, for laser marking, in security materials, in thermal protection, for seed coloring, for food coloring Drug coatings, in dry preparations, in pigment preparations, for analytical purposes, as a switch or as a tracer. In the case of cosmetic formulations, the pigments of the invention are particularly suitable for products and formulations of decorative cosmetics, such as nail polishes, coloring powders, lipsticks or eye shadows, soaps, toothpastes, etc. Of course, the pigments of the invention in the formulations with any type of cosmetic raw - And excipients are combined. These include oils, fats, waxes, film formers, preservatives and general performance properties determining adjuvants, such as thickeners and rheological additives such as bentonites, hectorites, silica, Ca silicates, gelatin, high molecular weight carbohydrates and / or surface-active aids, etc. The formulations containing pigments according to the invention may belong to the lipophilic, hydrophilic or hydrophobic type. In the case of heterogeneous formulations with discrete aqueous and nonaqueous phases, the pigments according to the invention may each contain only one of the two phases or may also be distributed over both phases.

The pH values of the formulations may be between 1 and 14, preferably between 2 and 11 and more preferably between 5 and 8. There are no limits to the concentrations of the interference pigments according to the invention in the formulation. Depending on the application, they can range from 0.001 (rinse-off products, eg shower gels) to 99% (eg glossy effect items for special applications). The pigments according to the invention can furthermore also be combined with cosmetic active ingredients. Suitable active ingredients are, for example, insect repellents, UVA / BC protective filters (eg OMC, B3, MBC), anti-aging active ingredients, vitamins and their derivatives (eg vitamin A, C, E, etc.), self-tanning agents (eg DHA, eryolose and others) such as bisabolol, LPO, ectoine, emblica, allantoin, bioflavanoids and their derivatives. When using the pigments in paints and coatings, all applications known to the person skilled in the art are possible, for example powder coatings, automotive coatings, printing inks for gravure, offset, screen or flexographic printing and for coatings in outdoor applications. For the production of printing inks is a variety of binders, especially water-soluble

Types suitable, e.g. based on acrylates, methacrylates, polyesters, polyurethanes, nitrocellulose, ethylcellulose, polyamide, polyvinyl butyrate, phenolic resins, maleic resins, starch or polyvinyl alcohol. The paints may be water- or solvent-based paints, the selection of the paint components is subject to the general knowledge of the skilled person. If, for example, they contain liquid-crystalline substances in their cavities, the pigments can be used for switchable lacquers, e.g. used for automotive applications. In the simplest case, an electric field is built up, with the sheet metal body as an electrode and a conductive coating, e.g. an ITO particle-containing layer as a counter electrode. Alternatively, the control of the liquid-crystalline substances can also be effected by the ambient temperature.

In addition, the pigments of the invention for

Pigmentation of films and plastics are used, such as for agricultural films, infrared-reflective films and discs, gift wrap, plastic containers and moldings for all known in the art applications. Suitable plastics are all common plastics for the incorporation of the moldings of the invention, for example thermosets or thermoplastics. The description of the possible applications and the usable plastics, processing methods and additives can be found, for example, 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 of which is included here. Because of the special angle-dependent color effects in combination with the background, body or LuminesΣenΣ color pigments of the invention are also suitable for use in security applications, such as Σ.B. in security printing and in security-relevant features for eg counterfeit-proof cards and

ID cards, such as Tickets, identity cards, banknotes, checks and check cards, as well as other forgery-proof documents. In the field of agriculture, the pigments can be used to color seed and other raw materials, and in the food industry to pigment

Food. For pigmentation of coatings in medicaments such as e.g. Tablets or dragees, the pigments of the invention are also useful, e.g. in DE 198 31 869 or US 6,627,212.

Furthermore, the pigments according to the invention are suitable for use in switchable systems, in particular when the voids between the rods and / or in the tubes are filled with substances, e.g. liquid crystalline substances are filled. By the action of external influences, e.g. electric fields can be controlled in this way the transparency and / or the reflectivity.

In addition, the pigments obtained according to the present invention are suitable for analytical purposes, for example in microanalysis or sensor systems. Thus, it is conceivable that the specific analyte changes the refractive index contrast by entering the pores. This leads to a change in the optical properties which can be detected. Here, for example when SiO _{2 is selected} as the pigment material, it is also conceivable to dock special functional groups on the silanol-containing surface in the cavities, which makes possible a specific detection. The pigments of the invention are also suitable for use in blends with organic and / or inorganic colorants, for example organic or inorganic dyes and / or pigments, such as transparent and opaque white, colored and black pigments and with platelet-shaped iron oxides, organic

Pigments, holographic pigments, LCPs (Liquid Crystal Polymers) and conventional transparent, colored and black luster pigments based on metal oxide-coated platelets based on mica, metal, glass, Al ₂ O ₃ , Fe ₂ O, SiO ₂ , etc. The pigments according to the invention can be mixed in any ratio with commercial pigments and fillers.

As fillers are e.g. natural and synthetic mica, nylon powder, pure or filled melanin resins, talc, glasses, kaolin, oxides or hydroxides of aluminum, magnesium, calcium, zinc, BiOCl, barium sulfate, calcium sulfate, calcium carbonate, magnesium carbonate, carbon, and physical or chemical combinations of these substances to call. There are no restrictions on the particle shape of the filler. It can meet the requirements according to e.g. be platy, spherical or needle-shaped.

The pigments according to the invention are furthermore suitable for the preparation of flowable pigment preparations and dry preparations comprising one or more pigments according to the invention, binders and optionally one or more additives. Dry preparations are also to be understood as preparations which contain 0 to 8% by weight, preferably 2 to 8% by weight, in particular 3 to 6% by weight, of water and / or of 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 particular application of the pigments of the invention consists in their use as tracers in mixtures with other organic and / or inorganic colorants. Tracers are widely used as a means of identification in modern products. With their

Help should prove the authenticity of a product or reconstruct the origin of a product. Common tracers are based on fluorescent, radioactive or luminescent substances which are added to the product to be protected as a powder, suspension or liquid. These substances are often toxicologically and environmentally questionable or require for their traceability special equipment and devices.

The pigments of the invention may be added to the colorants to be labeled or products made therefrom, e.g. Varnishes, powders, paints or suspensions may be added using all methods known to those skilled in the art. The proportion of the tracer in the product to be labeled is usually <5 wt .-%, based on the labeled product and preferably <2 wt .-% and most preferably 0.1-1 wt .-%.

Depending on the size of the pigments of the invention, the tracer in the mixtures can be detected very easily by means of a microscope or with the scanning electron microscope. Chemically and toxicologically, these tracers behave like effect pigments and are thus chemically inert and toxicologically harmless. The pigments of the invention can be mixed in very small doses, so that the coloristics in the application is not significantly affected. Since the pigments of the invention specially adapted to the customer's requirements for this application are not commercially available, sufficient copy protection of the mixture to be marked is ensured. Because of the stability and the chemically inert character, the pigments according to the invention can be used simply and without problems and processed in the abovementioned applications or formulations. Paints, lacquers, printing inks, plastics, films, cosmetic or pharmaceutical formulations, ceramic materials, glasses, paper,

Safety materials, seeds, food, pharmaceuticals, analysis systems, switches, dry preparations or pigment preparations containing the pigments according to the invention are accordingly also the subject of this invention.

The following examples are intended to illustrate the invention without, however, limiting it. Further examples are accessible in an analogous manner.

Example: AR glass tubes (composition: 69% by weight SiO ₂ , 1% by weight B ₂ O ₃ , 4

Wt% Al ₂ O ₃ , 13 wt% Na ₂ O, 3 wt% K ₂ O, 5 wt% CaO, 3 wt% MgO, 2 wt% BaO) with outside diameters of 1.7 mm and inner diameters of 1,204 mm are arranged hexagonally so that the overall diameter of the assembly is about 4 mm. The hexagonal arrangement is introduced at a feed rate of 1.5 mm / min in a 3-zone oven (zone height 10 mm) with a temperature of 700 ⁰ C. The drawing speed during drawing is 400 mm / min. The stretching is repeated until fibers with a diameter of 100 μm are obtained. After comminution of the resulting fibers cylindrical pigments are obtained, which have viewing angle-dependent color play from red to yellow to green when viewed.

Claims

claims 1. Pigments based on cylinders or prisms, characterized in that the height of the cylinder or prisms is 100 nm to 500 microns and that the diameter of the base of the Cylinder or the shortest diagonal of the base of the prisms is 100 nm to 500 microns and the cylinders or prisms of juxtaposed and lying in the direction of the height axis of the cylinder or the prisms tubes and / or rods. 2. Pigments according to claim 1, characterized in that the prisms have a base area in the form of a polygon V _n with n as the number of corners of the polygon V _n and n> 3. 3. Pigments according to claim 2, characterized in that n = 3, 4, 5, 6, 7, 8, 9 or 10. 4. Pigments according to one of claims 2 or 3, characterized in that the edge lengths of the polygons V _{n are the} same or not equal. 5. Pigments according to one of claims 1 to 4, characterized in that the cylinders or prisms are straight or inclined cylinders or prisms. 6. Pigments according to one of claims 1 to 5, characterized in that the surface of the tubes and / or rods or the prisms or cylinders is structured. 7. pigments according to one of claims 1 to 6, characterized in that the tubes and / or rods of the cylinder or prisms made of glass, SiO ₂ , B ₂ O ₃ , Al ₂ O ₃ , metals, plastics or mixtures of these materials or that the cylinders or prisms as well as tubes and / or rods contain these materials. 8. Pigments according to claim 7, characterized in that the cylinders or prisms contain tubes and / or rods of glass and metals. 9. Pigments according to claim 7 or 8, characterized in that the metal is germanium, gold, platinum, silver, lead or silicon. 10. Pigments according to claim 8, characterized in that the tubes and / or rods of metals along one or more Diagonals of the base of the cylinder or prisms lie. 11. pigments according to any one of claims 7 to 10, characterized in that the tubes and / or rods or the resulting bundles with one or more transparent, semitransparent and / or opaque layers containing metal oxides, metal oxide hydrates, metal suboxides, metals, metal fluorides, Metal nitrides, metal oxynitrides or mixtures of these materials are coated. 12. Pigments according to claim 11, characterized in that the one or more transparent, semitransparent and / or opaque layers doped with metal oxides, metal oxide hydrates, metal suboxides, metals, metal fluorides, metal nitrides, metal oxynitrides and / or mixtures of these materials doped with colorants and / or elements are. 13. Pigments according to one of claims 1 to 12, characterized in that the tubes and / or rods have outer diameters of 40 nm and 250 microns. 14. Pigments according to one of claims 1 to 13, characterized in that the diameters of the tubes and / or rods or of the tube walls enclosed pores in the pigments are the same size or not equal. 15. Pigments according to one of claims 1 to 14, characterized in that the pigments are additionally coated with 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 of these materials , 16. Pigments according to claim 15, characterized in that the one or more transparent, semitransparent and / or opaque layers containing metal oxides, metal oxide hydrates, metal suboxides, metals, metal fluorides, metal nitrides, metal oxynitrides and / or Blends of these materials are doped with colorants and / or elements. 17. Pigments according to one of claims 1 to 16, characterized in that the tubes to the prism or Cylinder bases are closed. 18. Pigments according to one of claims 1 to 17, characterized in that the cavities between the rods and / or tubes or in the tubes are filled with substances. 19. Pigments according to one of claims 1 to 18, characterized in that the pigments are provided with a secondary coating. 20. Pigments according to claim 19, characterized in that the Postcoating consists of organosilanes and / or polymers. 21.A process for the preparation of pigments according to claim 1, comprising the process steps a) arranging tubes and / or rods in the form of cylinders or prisms, b) thermally drawing the cylinders or prisms obtained in a), so that the diameter of the base of the Cylinder or the shortest diagonal of the base of the prisms is 100 nm to 500 microns and c) crushing the cylinder or prisms obtained in b), so that the height of the cylinder or prisms is 100 nm to 500 microns. 22. The method according to claim 21, characterized in that it is in the obtained in the process steps a) and b) cylinders or Prisms around Photonic Crystal Fibers. 23. The method according to claim 21, characterized in that the tubes and / or rods of the cylinder or prisms of glass, SiO ₂ , B ₂ O ₃ , Al ₂ O ₃ , metals, plastics or mixtures thereof Materials or that the cylinders or prisms contain tubes and / or rods of these materials. 24. The method according to claim 23, characterized in that the cylinders or prisms tubes and / or rods made of glass and metals. 25. The method according to claim 24, characterized in that the tubes and / or rods of metals along one or more diagonals of the base surface of the cylinder or prisms are arranged. 26. The method according to any one of claims 21 to 25, characterized in that the tubes and / or rods or the resulting bundles in advance with one or more transparent, semitransparent and / or opaque layers containing metal oxides, metal oxide hydrates, metal suboxides, metals, metal fluorides , Metal nitrides, Metal oxynitrides or mixtures of these materials are coated. 27. The method according to any one of claims 21 to 26, characterized in that the pigments additionally with one or more transparent, semitransparent and / or opaque layers containing metal oxides, metal oxide hyd rate, metal suboxides, metals, metal fluorides, metal nitrides, metal oxynitrides or mixtures of these materials be coated. 28. The method according to any one of claims 21 to 27, characterized in that the pigments are provided with a post-coating. 29. The method according to any one of claims 21 to 28, characterized in that the crushing is done by milling, cutting and / or chopping. 30. The method according to any one of claims 21 to 29, characterized in that the tubes to the prism or Cylinder bases are closed. - 3ö - 31. The method according to claim 30, characterized in that the closure is effected by melting, capping, grafting and / or by polymerization. 32. The method according to any one of claims 21 to 31, characterized in that the cavities between the rods and / or tubes or in the tubes are filled with substances. 33. Use of pigments according to claim 1 in paints, lacquers, printing inks, plastics, films, cosmetic or pharmaceutical formulations, ceramic materials, glasses, paper, for laser marking, in security materials, in heat protection, for seed coloring, for food coloring, in drug coatings, in Dry preparations, in pigment preparations, for analytical purposes, as a switch or as a tracer. 34. Use according to claim 33, characterized in that the pigments are mixed with organic and / or inorganic colorants. 35. paints, lacquers, printing inks, plastics, films, cosmetic or pharmaceutical formulations, ceramic materials, glasses, paper, safety materials, seeds, food, pharmaceuticals, analysis systems, switches, dry preparations or pigment preparations containing one or more pigments according to Claim 1.